development of a power unit using the human power

Mansoura University Faculty of Agriculture Dept. of Agric. Engineering

DEVELOPMENT OF A POWER UNIT USING THE HUMAN POWER BY WAEL MOHAMMED FAHMY FATH ABO TALEB EL KOLALLY B.Sc. in Agriculture Science, Tanta University, 2003 THESIS Submitted in the Partial Fulfillment of the Requirements for the Degree of MASTER OF SCIENCE IN AGRICULTURAL SCIENCE (AGRICULTURAL ENGINEERING) Supervisors Prof. Dr. Mohamed A. El-Sheikha Prof. Dr. Hesham N. Abd-Elmageed Prof. of Agric. Engineering, Prof. of Agricultural Engineering, and Faculty of Agriculture, Dean Faculty of Agriculture Mansoura University Mansoura University Dr. Mohamed A. Mostafa Lecturer of Agric. Mech. Faculty of Agriculture, Mansoura University

2008

Mansoura University Faculty of Agriculture Agric. Eng. Department

SUPERVISION Thesis Title

: DEVELOPMENT OF A POWER UNIT USING THE HUMAN POWER

The Researcher: WAEL MOHAMMED FAHMY FATH ABO TALEB EL KOLALLY

Thesis Supervised by: No.

Name

1

Prof. Dr. M. A. EL SHIEKHA

2

Prof. Dr. H.N. Abd-Elmageed

3

Dr. M.A. Mostafa

Position

Signature

Prof. of Agric. Eng. Faculty of Agric. Mansoura University Prof. of Agric. Eng., and Dean Faculty of Agric Mansoura University Lecturer of Agric. Eng. Faculty of Agric., Mansoura University

Date: 17 / 10 / 2008

Head of Dept

Vice Dean for Postgraduates

Dean

S. M. Abdellatif

El-S. M. El-hadidy

H.N. Abd-Elmageed

Mansoura University Faculty of Agriculture Agric. Eng. Department

APPROVAL SHEET Thesis Title

: DEVELOPMENT OF A POWER UNIT USING THE HUMAN POWER

The Researcher: WAEL MOHAMMED FAHMY FATHY ABO TALEB EL KOLALLY Approved Committee:

No.

Name

Position

1

Prof. Dr. M. M. MOSTAFA

2

Prof. Dr. M. M. IBRAHIM

3

Prof. Dr. M. A. EL SHIEKHA

4

Prof. Dr. H.N. Abd-Elmageed

Signature

Prof. of Agric. Eng. Faculty of Agric. Ain Shams University Prof. of Agric. Eng. Faculty of Agric. Mansoura University Prof. of Agric. Eng. Faculty of Agric. Mansoura University Prof. of Agric. Eng., and Dean Faculty of Agric Mansoura University

Date: 17 / 10 / 2008

Head of Dept

Vice Dean for Postgraduates

Dean

S. M. Abdellatif

El-S. M. El-hadidy

H.N. Abd-Elmageed

‫سبحانك ال علم لنا إال ما علمتنا‬ ‫إنك أنت العليم الحكيم‪.‬‬ ‫صدق اهلل العظيم‬ ‫اآلية (‪ )23‬سورة البقرة‬

CONTENTS Page 1- INTRODUCTION

1

2- REVIEW OF LITERATURE

3

2-1- Human power:

3

2-1-1- Human-powered vehicles

3

2-1-2- The human engine

3

2-2- The Mechanization systems

5

2-2-1- An overview of farm power in Africa.

5

2-2-2- Constraints and opportunities of power sources

7

2-3- Analysis of muscle coordination pedaling

8

2-3-1- Coordination between the two lower limbs

8

2-3-2- Coordination of muscles of the lower limb

10

2-4- Forces operating on a bicycle moving

14

2-5- Small tractor in developing countries

16

2-5-1- Tractor Development

16

2-5-2- Tractor Conformation

17

2-5-3- Traction characteristics of agricultural tractor

19

2-5-4- Mechanical aids for small farmer

21

I

2-6- Comparing between tractor tires

26

2-6-1- Air filed tire

28

2-7- Effect of tire inflation pressure on slippage

29

2-8- Effect of adding weights and tracted ones on drive wheel slippage

32

2-9- Effect of adding weights to tractor on its traction ability on paved road

32

2-10- Mathematical Analysis

33

2-10-1- Determination of forward speed of prone cart

33

2-10-2- Determination of slip percentage of prone cart

33

2-10-3- Determination of traction force of prone cart

34 35

3- MATERIALS AND METHODS 3-1- Materials

35

3-2- Equipments

35

3-2-1- Developed human power prone cart

35

3-2-1-1- Structure of the prototype.

36

3-2-1-2- Specifications of the prototype

36

3-2-1-3- Components of the prototype

36

3-2-1-4- Transmission System

42

3-2-1-4-1- Variable pulleys and V-belt drive

II

43

3-2-1-4-2- Gears and chain

43

3-2-1-4-3- Flywheel

43

3-3- Experimental procedure

44

3-3-1- Pre-experimental procedure

44

3-3-2- Field experimental design

44

3-3-3- Treatments

45

3-4- Instruments

48

3-4-1- Mechanical dynamometer (double spring balance)

48

3-4-2- Stop watch

48

3-4-3- Pressure gauge

49

3-4-4- Road type

49

3-5- Methods

50

3-5-1- Traction force measurement by wooden trailer

50

3-5-2- Human power unit performance

51

3-5-2-1- Determination of forward speed of prone cart

51

3-5-2-2- Determination of slip percentage of prone cart

52

3-5-2-3- Determination of traction force of prone cart:

53 54

4- RESULTS AND DISCUSSION 4-1- Machine Performance and Evaluation

III

54

4-1-1- The paved road

54

4-1-1-1- Forward speed

54

4-1-1-2- Slippage

64

4-1-1-3- Drawbar pull

73

4-1-1-4- Optimum operational conditions at paved road. 82 4-1-2-The unpaved road

83

4-1-2-1- Forward speed

83

4-1-2-2- Slippage

92

4-1-2-3- Drawbar pull

101

4-1-2-4- Optimum operational conditions at unpaved road.

110

5- SUMMARY AND CONCLUSION

111

6- REFRENCES

117

APPENDICES

128

ARABIC SUMMARY

141

IV

LIST OF FIGURES Fig, No

Page

2.1

Human Powered Vehicle

4

2.2

Coordination between the two lower limbs.

8

2.3

Couple pedaling measured at 120 W at the unilateral pedaling without (A) and back Information (B). To condition B, the subjects could see on a screen the intensity of Cp. The Hatched curve corresponds to Cp obtained at the unilateral pedaling

9

2.4

Model coordination of pedaling.

11

2.5

Illustration management's control of the force applied on the pedal

11

The forces operating on a bicycle moving up in a straight line.

15

The results of measuring bicycle velocity on a decline in units of km/hr as a function of time (seconds).

15

The treads of the tires are quite different; from left to right R-1, R-4 and R.3.

28

3.1

Schematic diagram of the human power unit (prototype).

40

3.2

The photograph of human powered prone cart.

41

3.3

Photograph of the power prone cart transmission system.

42

3.4

The different locally pulley used

43

2.6 2.7 2.8

V

3.5

Sketch of transmission system.

43

3.6

: The experimental design in paved road.

46

3.7

The experimental design in unpaved road.

47

3.8

Dynamometer (Double spring)

48

3.9

Stop watch.

48

3.10

Pressure gauge

49

3.11

The wooden trailer

50

4.1

Effect of drawbar height and adding weights on forward speed at three different tire inflation pressures (TIP) at reduction ratio of (1:4.5).

56


58


60

Effect of tire inflation pressures (TIP) on forward speed at three drawbar heights and three reduction ratios (RR) at three traction weights (A) 75 kg, (B) 100 kg and (C) 125 kg.

63

Effect of drawbar height and adding weights on slippage at three different tire inflation pressures (TIP) at reduction ratio of (1:4.5).

65


67

4.2

4.3

4.4

4.5

4.6

VI

4.7

4.8

4.9

4.10

4.11

4.12

4.13

4.14

4.15

Effect of drawbar height and adding weights on slippage at three different tire inflation pressures (TIP) at reduction ratio of (1:2.5). Effect of tire inflation pressures (TIP) on slippage at three drawbar heights and three reduction ratios (RR) at three traction weights (A) 75 kg, (B) 100 kg and (C) 125 kg

69

72

Effect of drawbar height and adding weights on drawbar pull at three different tire inflation pressures (TIP) at reduction ratio of (1:4.5).

74


76


78

Effect of tire inflation pressures (TIP) on drawbar pull at three drawbar heights and three reduction ratios (RR) at three traction weights (A) 75 kg, (B) 100 kg and (C) 125 kg

81


84


86


88

VII

4.16

4.17

4.18

4.19

4.20

4.21

4.22

4.23

4.24

Effect of tire inflation pressures (TIP) on forward speed at three drawbar heights and three reduction ratios (RR) at three traction weights (A) 75 kg, (B) 100 kg and (C) 125 kg.

91


93


95


97

Effect of tire inflation pressures (TIP) on slippage at three drawbar heights and three reduction ratios (RR) at three traction weights (A) 75 kg, (B) 100 kg and (C) 125 kg

100


102


104


106

Effect of tire inflation pressures (TIP) on drawbar pull at three drawbar heights and three reduction ratios (RR) at three traction weights (A) 75 kg, (B) 100 kg and (C) 125 kg

109

VIII

1- INTRODUCTION In agricultural mechanization the mainly power used now is the mechanical power. As a source of power it is most expensive, polluted the environment and need a wide road. In Egypt the agricultural road is narrow especially in the village and between fields. From century ago, farmers all over the world began the field work depending mainly on animal power. But the human was the safe power. The farmers can use safe mechanical mechanisms to do some agricultural operation such as transporting the seeds, chemicals, nurslings and some tools to the field and any other things from field and plowing planting and harvesting the small fields...etc. The aims of the present study are to develop, fabricate, and evaluate a power unit using the human power prone cart to suit the Egyptian farming conditions, such as the small farms using the human power to provide job opportunities for youth. The prototype machine was developed. To achieve the purpose of the developed machine, the following points were considered: The machine should be simple in design and easy to operate. It should be constructed by available and local materials to decrease its costs. It should be safety operating power, to provide job opportunities for youth that it was made with at pest two young people.

It should be small with high efficiency to be suitable for small farms as that it can move easily between the crops rows and turns in small area. It should use standard components to reduce repair and maintenance. It can be used for transport from house to field seeds, chemicals, nurslings and some tools …etc. It can be used for planting, chemical spraying, dusting, cultivating and harvesting the small fields. The objective of the present study was planned to be realized through the following stages: Determining the basic data which are considered as engineering parameter for developing specific power unit "prone cart" or working principles. Develop, and fabricate the human power unit to meet the small farmer needs for small farms. Studying, testing and evaluating some of the important engineering factors that affect the mechanical performance of the developed human power unit.

2

2- REVIEW OF LITERATURE 2-1- Human power: 2-1-1- Human-Powered Vehicles Joseph A. Paradiso (2003) Human-powered vehicles may be used under the following conditions: a.

All riders and passengers must wear protective equipment as required.

b.

Stunt riding of any type on any vehicle requires the use of a suitable

helmet. c.

No riding in areas that might block or impede foot or vehicular traffic

or create a hazard to others. d.

No sketching or other riding in close proximity to a moving vehicle.

e.

All vehicles must be operated in a safe manner.

f.

All vehicles must be parked in a safe manner when they are not in use.

2-1-2- The Human Engine Malewicki (1983) gave a landmark paper at the International Human Powered Vehicle Association Scientific Symposium, in which he presented a graph showing the maximum duration of human effort for various steady power levels. This graph has been reproduced below for convenience. Notice from the graph that an average "healthy human" can produce a steady 0.1 horsepower for a full eight hour period, while a "first class athlete" can produce 0.4 horsepower

for a similar period. Note that each data point on the curves represents an exhausted human. No more power is available without some rest and recovery. Thus at 0.4 hp the "healthy human" becomes exhausted within 10 minutes.

Fig. (2.1): Human Powered Vehicle. Note that in the power equation the units of power is watts (W), however we can apply the conversion 0.1 hp = 75 W (approximately) in reading the graph. Once you have decided the steady power level that you can comfortably apply at the pedals, it would be of interest to know the velocity that you will achieve at steady state when all other parameters are maintained at constant values. Hanna (1976) The Farmers when work in agriculture considering the man power equals 0.1 hp, Animal power (is 0.15 hp./Fadden) and Mechanical power (is 0.12 hp./fadden). It can be noticed that the available mechanical power on the Egyptian farms is lower than the minimum value (0.21 hp/fadd.) required achieving ideal agricultural production. We still need 540000 hp to get the

4

minimum value of 0.21 hp./Fadden. This means that we require tractors with almost power of 90000 hp. We must provide our agricultural production with suitable size tractors suitable for farm size. We can express the size of a tractor by its weight, its ‎power, and implements capacity. Brian G. Sims (2005) tested the human being can haul a load of almost unlimited size given unlimited time theoretically. Then practically the most people can comfortably pull 137 kg with a typical mountain bike and cargo trailer or cargo trike. A person can move load of that weight will depend on his or her physical condition. Someone in reasonable physical condition can generally pull 137 kg load at (16 km/hr) on level ground if there's no wind. A person exerting the same effort could pull a load of 275 kg at a speed of (11 - 13 km/hr). He added that a lower gear ratio is preferred when accelerating, pulling heavy loads, climbing hills, or riding into the wind to reduce the amount of pedaling effort required.

2-2- The Mechanization systems 2-2-1- An overview of farm power in Africa. Josef Kienzle et al. (2006) stated that mechanization systems are categorized into human, animal and mechanical technologies. Based on the source of power, the technological levels of mechanization have been broadly classified as hand-tool technology, draught animal technology and mechanical power technology.

5

A series of studies on farm power conducted by FAO in Africa in the years 2002–2004 have shown that the principal labour-demand peaks in the farming cycle are for land preparation and subsequent weeding. The constraints to increased farm production are due, to a large extent, to three factors: • An excessive reliance on human power; • The low productivity of human labour; • A decrease in the labour available. Human power: With human power, productivity is generally low because of the lack of physical energy available and the limited range of hand tools. The situation has been exacerbated by the Human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) pandemic and other factors, such as migration, which reduce the numbers of young, healthy people available for farm work. Draught animal power (DAP): Draught animal power is generally considered to be an affordable and sustainable source of power for small scalefarms. Oxen and sometimes cows are the animals of choice, but in some African cultures it is unacceptable for women to use bovines. Donkeys and horses are increasingly being used, as are camels and mules in some areas. Apart from tillage, transport and other field operations, work animals can also be used for logging, pond excavation, and rural road maintenance. Tractor power: Government-run tractors hire schemes in Africa, never widely effective, are now in a state of collapse following a reduction in government expenditure on services that could, theoretically, be provided by the

6

private sector. Private sector tractors have been profitable on large landholdings, but they have seldom proved viable for the smallholder sector in Africa, whether in individual or group ownership, or in private hire services.

2-2-2- Constraints and opportunities of power sources Josef Kienzle et al. (2006) Stated that the human muscles still contribute about 65 percent of the power for land preparation in Africa. A typical farm family that is reliant solely on human power can only cultivate in the region of 1.5 ha per year. This will rise to 4 ha if draught animal power (DAP) is available, and to over 8 ha if tractor power can be accessed. It is quite common to combine available power sources in order to increase the area farmed, or to reduce the burden on humans. Tractors or draught animals can be hired for primary tillage and subsequent planting, and weeding can also be done with a combination of power sources and technologies. Application of these alternative power sources can relieve pressure on human labour at critical times of heavy demand. Making more efficient use of human power, together with the efficient application of draught animal power, provides the best immediate strategy for reducing the problem of farm power shortage in Africa, thereby increasing agricultural productivity and improving the livelihoods of millions of families in the shortest time.

7

2-3- Analysis of muscle coordination pedaling 2-3-1- Coordination between the two lower limbs Fregly et al. (1996) Generate a couple pedaling; central nervous system must enable the most of the muscles of the lower limb. Fig. 2.2 shows the main pre-and post muscles of the lower limbs that are active during the pedaling motion.

Fig. (2.2): Coordination between the two lower limbs. Ting et al. (1998) Indicated that in other such locomotion's biped walking and running, Central nervous system must coordinate when pedaling movements of the two Lower limbs, for example, during the descent of the pedal, while one performs extension, the other must realize bending. Such coordination in opposition phase is facilitated by the fact that cranks are diametrically opposed

8

on the pedals. The study showed that the muscle coordination of unilateral pedaling Different from the pedals bilateral. The subjects are seeking more For the hip flexor (RF) and knee (BF) to overcome the weight of a member Since lower

back-pedal

is

no

longer

assured

by

the

member

opposite.

The negative Cp product during the recovery phase is decreased by 86%. Subjects moreover do not reproduce the same amount of Cp negative even if they can view the intensity of Cp on a screen (see Fig. 2.3). The authors suggested that flexor activity is inhibited when bilateral pedaling by the Information from relevant zones and neuromuscular Mechanoreceptors knee extensor opposed. As they are inactive When pedaling unilateral no force being generated, this inhibition would delete. The driver does not therefore differ between universities and pedal ages Bilateral; it is only his speech to be altered.

Fig. 2.3: Couple pedaling measured at 120 W at the unilateral pedaling without (A) and back Information (B). To condition B, the subjects could see on a screen the intensity of Cp. The Hatched curve corresponds to Cp obtained at the unilateral pedaling (Ting et al. 1998).

9

2-3-2- Coordination of muscles of the lower limb Raasch et al. (1997) showed that the movement is essentially pedaling generated from the activation of three pairs of two muscle groups antagonists (see fig. 2.4). According to these authors, a muscle can generate, absorb and transfer of energy by acting as a rigid link to accelerate the member lower. In this model, the pair ext / flex, formed by the extensor gouty of the hip (GM) and knee (VL, VM, VI) and the flexor gouty of the hip (PS) and knee (BFcc), produces the energy needed to propel the crank, respectively, during the descent and the ascent of the pedal. The Two other pairs, on the one hand, by plantar flexors and backbones of ankle (pair plant / dorsi), and on the other hand, by the bi-muscles and joints RF IJ (pair ant / post), generate energy to propel the crank at a standstill Low (BFlc, SM, ST, GAS, SOL) and the top dead (RF, TA) to ensure the continuity of pedaling. The muscles BFlc, SM & GAS also transfer energy produced by the extensor during the descent of the pedal. The TA transfer energy produced during the rise of the pedal by mono-articular flexor. This model reduces the number of degrees of freedom control movement since the central nervous system has more than three pairs of two opposing muscle groups to coordinate to generate the pedal. It may also be applied to analyze the coordination of pedaling backward (Ting et al. 1999, Neptune et al. 2000). In this case, only the coordination of the pair ant / post is reversed: the IJ are active during the passage of top dead and RF is activated at the low point death (see fig. 2.4). The function of the six muscle groups is not changed.

10

Fig. 2.4. Model coordination of pedaling. Ting et al. (2000) have suggested that muscles bi-articulaires Control the direction of the applied force on the pedal. According to this theory, The force applied on the pedal either towards the front at the first Part of the descent of the pedal, the RF must be co-active with the extensor To decrease the hip extensor moment of the hip and to increase the When the knee extensor (see Fig. 2.5 a). On the other hand, if the force applied the pedal will be directed down at second part of the descent of the Pedal, this time the IJ that must be enabled to increase the time Extensor of the hip and to decrease the time of the knee extensor (see Fig. 2.5 b).

Fig. 2.5: Illustration management's control of the force applied on the pedal

11

Clarys et al. (1988) have developed other hypotheses to explain the activity of Flexor during phase thrust: - First, it is unlikely that the IJ are activated during the second part The descent of the pedal to reduce the time created by the expanders The knee since the vast demands are no longer beyond 130 ° . - Secondly, IJ may work in concentric at the extension of Lower limb since opening angles of the hip and knee Change simultaneously. - Finally, by their nature bi-articulaires, these muscles may be solicited during the first part of the descent of the pedal, to achieve the extension the hip, and at the second part, to make the bending of the knee. From this point of view, there is therefore no paradox because their Lombard Activity is not opposed at the time net. Ericson (1988) has also suggested the muscles bi- articulaires (BFlc, SM, ST, GAS) provide as a priority two anatomical features: 

Extension of the hip for BFlc.



Bending the knee for the muscles SM, and ST GAS l.



Plantar flexion for the GAS m. He said that the DSA could be solicited during the second part of the descent

of the Pedal to continue the extension of the lower limb to a standstill bottom since the extension of the knee during this period is not due to the activity of Extensor but only the consequence of the mechanical fixing the foot on the pedal. The plantar flexor of the ankle (GAS, SOL) are activated at the same time That extensor of the hip and knee in the middle of the descent of the pedal (See Fig. 2.4).

12

Raasch et al. (1997) and Zajac et al. (2002) hypothesized that these Muscles are activated during the phase of power to pass The energy generated by the extensor of the hip and knee at the crank Since it is provided in large part to the lower limb (see Fig. 2.2). These the authors have shown that 56% of the energy generated during an exercise maximum by extensor mono joints of the hip and knee, is returned to the Crank through the GAS. Other authors (Clarys et al. 1988) by against suggested that the GAS is activated at the second part of the descent of the

Pedal

to

help

achieve

IJ

bending

of

the

knee.

So it is still unclear whether the paradox of Lombard really exists in cycling. Andrew (1987): concluded that "It is not easy, even in the simplest circumstances, to make a final judgment the presence or absence of an eccentric cycling." This problem therefore remains relevant Where: Cp: couple pedaling Cp delta: amplitude of the couple pedaling Cp max: maximum torque pedaling Cp min: minimum torque pedaling MS: mechanical efficiency FE: effective force FI: unnecessary force FN: normal force FR :resultant force FT: tangential force Fx: horizontal force applied on the pedal Fy: sagittal force applied on the pedal Fz: vertical force applied on the pedal

13

θc angle of the pedal θp: angle bracket ω: angular velocity of the pedal BB: biceps brachii BF: biceps femoris BFCC: biceps femoris short head BFlc: long head biceps femoris GAS :gastrocnemius GM: gluteus maximus ES: erector spinae IJ: ischios-leg PS: psoas-iliacus

FP: Cadence HFX: horizontal force applied on the handlebars HFZ: vertical force applied on the handlebars IRP: inertia reported to pedal ECP: mechanical power Ra: air resistance Rg: resistance of gravity Rr: rolling resistance Vd: speed

RA: rectus abdominis RF: rectus femoris SM :Semi membranosus SOL: soleus ST: Semi tendinosus TA: tibialis anterior TB: triceps brachii VL: vatus lateralis VM: vastus medialis

2-4- Forces operating on a bicycle moving Gil Baran (2005) resulted that the system of a bicycle and rider moving in a straight line is affected by a number of forces. It should be noted that this system cannot be represented as a simple point-like body and there is great importance to understand the background of how these forces operate. By pushing the pedals the cyclist created the rotational momentum that turns the front chain ring which via the chain turns the rear chain ring, attached to the rear wheel itself. The rear wheel turns and creates the frictional force on the ground which is directed backwards. According to Newton’s Third Law of Motion, the ground exerts an equal but opposite force on the bicycle, which is the force that actually propels the bike. (Fig. 2.6) illustrates the forces operating on a bicycle moving up an incline in a straight path. There are two main friction forces; the first is the rolling friction which dominates at low speeds while the air drag is dominates at high speeds in (Fig 2.7) presents a sample curve showing how velocity changes with time for a riding mass of 106.4 kg. From the curve one sees how the increase of speed of the bike gets

14

smaller and smaller, i.e. its acceleration decreases, until it reaches its terminal velocity of about 42 km/hr and zero acceleration. The displacement as a function of time can be obtained by time integration of the speed. There are two main friction forces; the first is the rolling friction which dominates at low speeds while the air drag is dominates at high speeds.

Fig. 2.6: The forces operating on a bicycle moving up in a straight line.

Fig. 2.7: The results of measuring bicycle velocity on a decline in units of km/hr as a function of time (seconds).

15

He resulted that for coasting experiment the bicycle moves under a continuously decreasing acceleration, due to air drag, which increases with speed. After about 50 second the net forces operating on the bike cancel out, with the bicycle, in this case, continuing to move at a fixed velocity of about 42 km/hr. According to the experiment described in the curve the total rider-bike mass was 106.4 kg.

2-5- Small Tractor in Developing Countries: 2-5-1- Tractor Development: ‎Barger et al. (1967) stated that the early steam engine furnished belt power but had to be pulled from place to place by horses or oxen, the next step in the evolution in Farm power was the conversion of the ‎steam engine into a selfpropelled tractor engine. Successful steam plows were developed in the decade of the 1850's and continuous development occurred during the ‎next 50 years. ‎They also showed that inadequate traction played the inventors of the large heavy tractors who tried to solve the problem by making the diving wheels wider and wider, one big-wheeled tractor was made in 1900, and ‎two wood convened drive wheels, each 15 ft. wide and ‎9 ft, in diameter. The outfit weighted 41 tons. Other attempts to solve the problem of traction resulted in the development of track - type agricultural tractor about 1900. ‎They indicated that the early attempts to develop gasoline. Tractors were stimulated by the need to reduce ‎the number of men required to attend the steam

16

tractors, both when plowing and when operating threshing machines. Early gasoline tractors resembled steam ‎tractors. ‎They showed that the development was needed before a reasonably successful internal combustion engine did not assume much importance until after the expiration of the Otto patents in 1890, also the first Winnipeg tractor trails were held in 1900 giving the public an opportunity to compare field operations of steam and gas tractors. ‎Succeeding trails were held each year through when they were discontinued. The first United States tractor demonstration, held at Omaha, Nebraska in 1911, was conducted as an exhibition, an‎d not as a competition between machines. The tractor test law, passed in 1919, which attained worldwide recognition, has provided standards for rating tractors, have speeded improvements and have eliminated were inferior in design and performance. ‎They also cleared that tractors sizes have increased with increasing farm sizes. In 1950- 90.8% of all wheeled tractors manufactured have less than 35 hp, while by 1960 the percentage of tractors of this size being made was reduced to 17%.

2-5-2- Tractor Conformation: ‎Gray (1954), showed that the first tractors were large and cumbersome and were suited mainly for plowing and threshing. Adaptations were made to use it as a motor cultivator, after which came the general purpose tractor to perform major farm operations. Rubber tires which greatly increased the tractor's flexibility were adopted in the decade of the 1930's.

17

‎He added that one descriptive classification of the tractor is based on the arrangement of the form and traction members; the means being descriptive of the general conformation or use of that type. Utility; Row-crop; standard wheel; Crawler; Front-wheel drivel four wheel drive, wheel steering, ‎Four wheel-drive Frame steering, Implement carrier, and Garden two - wheeled tractors ‎He also indicated that row-crop tractors in addition to being suitable for traction work are especially adapted for use on row crops, incorporating easy provision for quick attachment of various tillage and cultivation tools as well as implements for such takes mowing and handling forages. ‎He stated that the "tool carrier frame" tractor has especially been further development by German and the Soviet. As the name implies this tractor is an attempt to make one power perform a number of tasks. Prime consideration is given to the case with which various tools can be attached and to the versatility of the unit., The "implement carrier frame" tractor is an attempt to extend even further than the "tool carrier frame" the use of ‎the power unit. The design in such as to permit reasonably rapid exchange of complete machines such as a combine or cornier. ‎He stated, although garden tractors have been available in one form or another almost since the development of the internal combustion engine, it is only since World-War II that they have come into widespread use. The ready availability of small inexpensive, and compact engines, and the urbanization of homes

18

encouraged dozens of new manufacturers to enter this market. There are extensive lines of attachments available for many.

2-5-3- Traction Characteristics of Agricultural Tractor: Pripps ( 2001) told that the self-propelled agricultural vehicles have been used for over 100 years to replace animals to provide power to perform agricultural tasks. Steam engines were used in farming starting after the Civil War; however these massive machines were soon replaced. The first gasoline-powered tractor was made in 1892 by John Froehlich, a blacksmith from Iowa. Shortly thereafter in 1901, the first mass-produced tractors were sold by C.W. Hart and C.H. Parr of Charles City, Iowa. He added that observing the progression of the tractor through history, the trend has been towards larger and greater vehicles in large-scale production agriculture. In 1941, one could buy a Farm all HD, a large tractor for its time, which weighed approximately 5300 lb. Similarly, a 1947 Allis-Chalmers WF was 3500 lb and sold for around $1200. Deere, (2004) said that the range of size of the modern tractor has since grown significantly. Today, the largest row crop tractor made by John Deere weighs in at 23,050 lb and has a base price of $175,000. The benefits of large agricultural vehicles are obvious from the standpoint of conventional operatorcontrolled farming operations. The larger, more powerful tractors can pull larger implements to cover more land than smaller tractors that need more operators, thus minimizing human labor as much as can be done with human operated machinery.

19

Time, however, is not the only cost incurred by this type of operation. Research has shown that soil compaction by the driven wheel can reduce crop yield and have overall negative effects on soil. Soil compaction has several detrimental effects on crop growth. Soil density is increased, hindering root growth and limiting overall nutrient uptake. When soil porosity is significantly decreased, nitrogen availability can decrease due to denitrification. Furthermore, potassium uptake may be reduced if respiration within the root is reduced (Wolkolski, 1990). Chamen et al. (1992) tested a tracked gantry system, which applied no wheel pressure on the soil surface. They found that yield was up to 14% higher with no wheel pressure than with a conventional system with wheel pressure. Taylor and Williams (1959) indicated that the differences in the performance a low speeds and high drawbar pulls of wheeled tractor are due to different conditions of friction between the tires and the ‎track surface, for friction is the major factor in determining the maximum coefficient of friction of a‎‎tire on a hard surface. They stated that the magnitude of the maximum traction coefficient for an agricultural tractor tire depends on many factors. The most important of which are the shape and profile of the tread bars, the tire loading and contact area and the materials, finish and general state of the surface on which the tire is running; particles of rubber Worn off the tire, dust or other unwanted substances affect the state of the surface and the traction coefficient by affording what way be called a degree of Lubrication between drawbar pull and wheel slip of a tractor obtained both on the treadmill and on the concrete track show that the gaps

20

between adjacent blocks of the treadmill tracks have a negligible effect on the tire performance. Reed et. al. (1953) indicated that traction of ‎a rubber tire can be increased by decreasing its pressure because the contact area of the tire will then increase. They also stated that rolling resistance of a wheel will increase as the sinkage increases; the decreasing of the air pressure will decrease the sinkage. He added that as tire inflation pressure increases, the traction of a tire will decrease where sinkage would be large on sand surface.

2-5-4- Mechanical Aids for Small Farmer: Hill (1965) stated that many examples attempts exist for introducing the benefits of large scale mechanization to the small Farmer, notably in the form, group Farms, block Farms, or tractor hire services. There is an increasing reaction though; that many opportunities exist for extending the efficiency‎ of the small Farmer by the introduction of ‎simple mechanical additions and that is often neglected in countries where tractors mechanization makes overwhelming demands on resources. Akilimali (1966) showed that progress is being made in the study of agronomics of hand cultivations. This could obviously result in the development of improved hand tools and techniques, apart from enabling a more precise assessment to be made of the ‎, limitations of hand power in agricultural production. Chalmers (1962) stated that even more spectacular has been the progress in the development of ox equipment and techniques, ranging from improved ox

21

handling and management techniques, to quite out standing achievement in the development of ox toolbars and tool frames. Cogge (1966) mentioned that real progress can ultimately only be attained after the conversion of rural communities through extension, to a more enlightened outlook as exemplified by the rural development project at Borgo a Mazzano in Italy. He also showed that the first phase of development efforts, with an advocating of the simplest of new practices for direct agricultural farmer content, which should follow in a subsequent phase. Pothgray (1969) indicated that the small tractor may be defined as being any tractor unit of 20 hp, or under designed to carry out of farm operations including transportation. He classified world tractors within these small tractors into some five groups as follows:  Conventional four-wheel agricultural tractors of 20 hp. And below.  Two-wheel agricultural/horticultural tractors of 5 hp. and upwards.  Smaller two-wheel tractors of under 5 hp.  Four-wheel specialized garden tractors of up to 7 or 8 hp. He stated that the fact remains that no developing country other than Taiwan and, to a lesser extent, India has based its mechanization program on tractor in this low horsepower class, in spite of the diversity of models available on the world ‎market. He added that the success story of Japan seems unlikely to be repeated elsewhere, and the reasons for this are investigation so as to better understand the

22

place of the small tractor in the Future. Japanese success may be attributed to the flowing: The climate, which is relatively temperature with soils and crops suited to the working of low horsepower units. Predominance of small holdings which are highly ‎productive per core per annum. The countryside, which has been tailored for use of small tractors particularly as regards farm access and transportation. The farming population, who are individualistic with an aptitude for machinery at farm and village level. The fact that Japan is an industrial nation and ‎although highly populated there has been a drift to the towns and many Farmers are Daly part timers. Japanese industry, which has seized the opportunity of vast home market where has been great competition to design low-cost machinery to meet local conditions. He also studied another case namely, that of India, where something of revolution is taken place in small farm mechanization. There, in spite of much government propaganda in Favor of the introduction and manufacture of two-wheel tractors, a major success has attended the introduction of 15 - 20hp. Four-wheel tractors mainly of East European and ‎Russian origin. The case of India is doubly interesting because it could well be the forerunner of development elsewhere, where conditions are similar. Morris and pollard (1981) pointed out that the main problem for small farmer is shortage of land, not of labor. That's why inputs which raise yields per

23

acre are a better buy than tractor which raise yield per worker. It is now largely agreed that the new and improved technologies to be adopted by the less developed countries must be both appropriate and acceptable. They indicated that small tractors have been viewed by their promoters as one stage in the dynamic process of farm mechanization. Critical questions in small tractor development must concern the mechanization needs of less developed farmer, and his ability to pay additional power inputs, as determined by: 1. Power requirements and the extent to which existing power supply is a constant to improvement. 2. His net income and expected net income with a small tractor. 3. The machine's price and associated ownership and ‎use costs. 4. The prices and net benefits of alternative power ‎sources. 5. The opportunity cost of the small tractor investment, would it be better spent on other items. ‎They added that within these factors other variables are important - the availability and cost of credit, the relationships .Between the price of small tractors on one hand and the price, availability and productivity of other farm inputs and the price rec1ievied for agricultural procure on the other hand, and the present level of farm mechanization technology. They indicated how these factors influence the demand for small tractor. A major variable is farm size. Some 80 - 90% of less developed countries holdings are below Five hectares, which combined with small Fragmented plots and

24

complex tendril patterns, limit the market for individual ownership and use of tractor farm power. Here the small tractor is only one alternative. As it stands ‎at present, its probably an inferior one both technically and financially. ‎They stated that of prime importance is the requirement that farmers be better off a result of using small tractors. However, low prices and low yields within a predominantly subsistence agriculture in the less developed countries restrict the Farmer's ability to adopt new and therefore "risky" technology. Josef Kienzle et al. (2006) ) said that there are several reasons people choose to transport cargo using a bike or trike:  Low equipment cost - A new cargo bike or trike usually costs substantially less than a motorized vehicle.  Non-polluting - The only pollution produced by a human-powered cargo vehicle is the carbon dioxide exhaled by the rider.  Usable indoors or outdoors - Because a human-powered vehicle produces no poisonous fumes, it can be used inside or outside.  Easily parked - A bike or trike doesn't require the amount of parking space as a car or truck, and can generally be parked anywhere.  Always available - A human-powered vehicle doesn't need to be refueled or recharged like gasoline or electric vehicles, so it is always ready to be used.  Great exercise - Transporting cargo using your own power is, of course, an especially good form of aerobic exercise. People who regularly haul cargo by bike are rarely fat.

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2-6- Comparing between tractor tires: ‎James H. Taylor (1976) reported that Since World War II there has been a

steady decline in United States farm population with an accompanying increase in farm size. Many farmers have purchased land scattered over a large area, and they drive their tractors on hard-surface roads between these farms, As a result the tread bars on the R-I tires. which are not designed for hard -surface operation, have worn rapidly. ‎The tires for driving wheels on agricultural tractors are classified in four categories: as shown in Fig.2.8: The treads of the tires R-1, regular tread; R-2, rice and cane or deep tread; R-3, shallow tread; and R-4, industrial tractor or intermediate tread. Total tire production figures for the industry for 1972-74 show that 83 percent of the drive tires produced were R-1tires. ‎The farm tire industry has long been aware of the rapid wear of R-1 tires on hard surfaces, and they have made some changes in tread design and rubber compounds in an attempt to partially alleviate the problem. However. the basic design of an R-I tread is conducive to rapid wear on hard surfaces because of the flexing and scrubbing of the long, narrow tread bar. A broad base. Shallow depth tread bar should wear much longer on hard surfaces, ‎The R-1trire has proved successful in most agricultural field conditions‎‎but the cost of rapid wear on hard surface has become a major economic factor for many American farmers. While theR-3 and R·4 tires have proven in the manufacturer's tests that they wear less than R-1 tires on ‎hard surfaces, the

26

farmer needs to know how much traction performance he could expect to give up in the field if he considered switching to the R-3 or R-4 tire design. ‎Several articles have been published which discussed the effects of tire tread variables (Taylor 1973. Taylor 1974) and the shape of the contact area Taylor and Burt 1975), However. Those articles referred to experimental devices which were not available to the farmer. The objective of this study was to compare the traction performance of three tires (R-1 R-3 and R-4). All in production and readily available, in a variety of soil conditions. And he concluded that: 1-Most farmers will need to ‎continue using the R-l tire because of the wide range of their traction conditions. ‎2-Those farmer's experiencing rapid wear on hard-~surface roads and who have few extremely difficult field conditions might consider the R-4 tire. ‎3- I n good traction conditions (travel reduction below 20 percent). the R-4 and even the R-3 tires are as effective as the R-I, based on the coefficient of traction. ‎4- An increase in the width to depth ratio of the R-I bar lug (bringing the design closer to the R-4) should improve tread wear characteristics on hard surfaces without seriously affecting the tire's traction performance. This report of traction performance studies shows that both the R-3 and the R-4 tires are only slightly less effective than the R-1tire below 20 percent travel

27

reduction. The tread of the R-4 tire will wear twice as long as the tread of the RI tire when both are operated on hard-surface roads.

Fig.2.8: The treads of the tires are quite different; from left to right R-1, R-4 and R.3.

2-6-1- Air filed tire McMullan et al. (1988) stated that: 

The inflation pressure of conventional tires may be reduced for

lightly loaded applications without the danger of tire collapse in situation where the tire is non-rolling and subjected to large side load. 

The aspect is not the critical factor when considering tire collapse.



Substantial lateral tire deflection may occur when tires at low

inflation pressure, are subjected to large side loads may have a significant effect on the roll stability of the vehicle. 

Further investigation is needed to determine the effect of both side

and tractive forces on a rolling tire before recommendations can be made on the use of conventional tires at low pressure.

28

Raper et al. (1995) reported that, increased inflation pressure decreased rut width but had little effect on deformed soil cross - sectional area. Increased inflation pressure decreased both the total contact length and the total contact area of the tire, while increased dynamic load increased both of these parameters.

2-7- Effect of tire inflation pressure on slippage: Abou- Elmagd (1982) resulted that the contact area of the tire with the ground will then increase by decreasing tire inflation. Increases of slippage percentage are due to increasing of rolling resistance of the drive-wheel as the sink age increases. Obviously by decreasing the air percentage in the tire, the sink age will decrease which in turn will decrease which in turn will decrease the rolling resistance. Bailey et al. (1991) concluded that, tractor tire inflation pressure affected stresses in soil beneath the tire in sandy load soil, while the same could not be concluded in clay loam soil. Bailey et al. (1995) showed that, higher inflation pressure tended to shrink the tire footprint and increase pressure across the tire. Decreasing inflation pressure increased the size of the footprint and decreased the pressure. In all cases pressure tended to be higher near the edge of tire footprint than at the center.

29

Bailey et al. (1996) found that, increasing dynamic load at a constant inflation pressure caused increasing soil stresses and bulk density. Burt and Bailey (1982) carried out an experiment to determine the effects of load and inflation pressure on tire. Results showed that, tractive efficiency at constant net traction can be maximized by selecting appropriates levels of dynamic load and inflation pressure. Bolling (1986) stated that, increasing tire diameter reduces the soil pressure because the constant area of such a tire is larger than that of one with a small diameter; larger constant area causes lower contact pressures and lower sinkage. Culpin (1981) mentioned that, the slippage of tractor drive wheel always wastes power fuel and with pneumatic tires this wastage may be serious, even if the wheels do not spin. A simple method of determining when a tractor is working is to make a mark on the tractor wheel and then measure the distance the tractor wheel moves forward in, say 10 revolutions of the wheel, first under load then on the same surface with no-load the slip percentage can be estimated. Domir (1978) and Abou sabe and Henein (1964) said that: 1-The most important factors affecting the drawbar performance are the soil itself and the weight that the tire carries. 2-Traction with high power to weight ratio have to travel faster to utilize the available horsepower or use added weight to operate at lower speeds 3-Inflaction pressure has an effect, lower pressures being advantageous on loosed, sandy soil. This disadvantage disappears in firmer soil.

30

4-despite advances in traction technology, the load to the power ratio and the speed of travel are still the main factors affecting maximum tractive efficiency Burt et al. (1982) stated that tractive efficiency was experimentally optimized for a radial-ply tractor tire. Resulted show that tractive efficiency can be significantly improved by selecting appropriate levels of inflation pressure and dynamic load for particular soil condition. The potential gains in tractive efficiency which could result from the application of automatic controls to field traction situations are explored. Kllefoth (1966) and Zombori (1967) showed that a decrease at inflation pressure increased the drawbar pull at constant travel reduction. Czako (1974) showed an increase in drawbar pull on loam soil of up to 20% when the inflation pressure was reduced from 240 to 103 kpa. El Sheikha (1995), stated that the tractor drawbar pull increases with increasing the drawbar height. This increase is attributed to the weight transferred due to the increase of the drawbar height. He added that increasing the drawbar height increased the weight transferred to the rear axle and soil reaction on it and this decreased the slip percentage, the lower the tire inflation pressure the larger will be the tire contact surface area of the tire with the ground, and consequently, the more will be the tire-ground grip, and vice versa so that the producers recommend lowering of the tire inflation pressure. The

31

traction coefficient gave the maximum values at the lower tire inflation pressures and the higher drawbars.

2-8- Effect of adding weights and tracted ones on drive wheel slippage: Abou- Elmagd (1982) indicated that the slippage percent increased with the increases of tracted weight, and decreased with the increases of ballast at the tractor. He added that the percent of slippage is lower on paved road than that on unpaved road. On other friction surface when the coefficient of friction increases the percent of slippage increase. He resulted that increasing the contact area of the drive-wheel with the ground decreased wheel slippage, on other words slippage percent decreased when the tire inflation was decreased.

2-9- Effect of adding weights to tractor on its traction ability on paved road: Abou- Elmagd (1982) said that the dynamometer readings increased linearly as the tractive weights increased. It is apparent that adding ballast weights to the tractor has positive effect on its tracted ability on the paved roads. It is apparent that traction force is affected by both area and weight on normal roads are cohesive and frictional. He said that it is apparent that sensible variation happened in rolling resistance force of the drive-wheel by the variation of the load on it. It is clear that rolling resistance force increased as the total weight on the drive-wheel increased. He concluded that the traction force

32

produced by the small tractor is mainly affected by the tractive weight, traction surface and the values of traction force were increased the coefficient of friction. He concluded that the drive-wheel slippage is highly affected by both adding ballast and tire inflation. It was observed that increasing the ballast decreased the drive-wheel slippage percent and concluded that the power requirements are affected by the values of traction force, rolling resistance and slippage percent.

2-10- Mathematical Analysis: 2-10-1- Determination of forward speed of prone cart: Forward speed could be calculated from the following equation by (John Willey 1997):

V

L …………………………………………..[2-1] T

Where: V= forward speed (m/sec.) L= distance from beginning of the line to its end, m T = Time consumed for this distance, sec

2-10-2- Determination of slip percentage of prone cart: The slip percentage is one of the parameters affecting the horsepower required from the power unit. Travel reclusion for any given weight is

33

determined using the following equation. Drive-wheel slippage could be calculated from the following equation, (Barger et. al. 1963)::  R  r  ……………………………[2-2] Percent slip 100    R 

Where:

R= total drive wheel revolution count to traverse the drawbar runway under load. r = total drive wheel revolution count to traverse the drawbar test runway

2-10-3- Determination of traction force of prone cart: The drawbar pull could be calculated from the following equation, (Barger et. al. 1963):

Tan  

difference s between the height degree …………………[2-3] horizontal distance

The corrected force = the obtained force Χ cos α Where: α = Angle between the horizontal axe and dynamometer hitch, degree.

34

3- MATERIALS AND METHODS 3-1- Materials: The present study was carried out at farms in Mansoura University. The procedure of this study involved four testing group: a- Determine the basic data necessary for develop the power unit prone cart. b- Fabricating and manufacturing the human power unit at local workshops in Mansoura University c- Preliminary tests were carried out at the same farms during season of 2006, to find out the mechanical defects of the developed machine and for further improvements. d- Field experiments were carried out at the same mentioned farms during season of 2007, to test human power unit criteria, such as design parameters operating performance, the forward speed, slippage and drawbar pull. The area allocated for the experiment two types of road were used, which were namely, paved (Asphalt) and unpaved roads.

3-2- Equipments: 3-2-1- Developed human power prone cart: Fig. 3.1 shows a schematic diagram of the prototype of the human power unit "prone cart" and Figs. 3.2 represents its features.

3-2-1-1- Structure of the prototype: The power unit (prone cart) was proposed as: 1- Using the local materials in all parts that can be constructed in Egypt. 2- Using small number of important parts. 3- Constructing the power unit suitable for the small farms that can move between the crop rows easily and turns in small areas. 4- Using the human power to provide job opportunities for youth that it was made with two people. 5- It can be used at transporting the seeds, chemicals, nurslings and some tools to the field. 6- It can be used to plant and harvesting the small fields.

3-2-1-2- Specifications of the prototype: The designed human power prone cart specifications are: 1- Total weight was 90 kg.

2- Wheel base was 143 cm

3- Total width averaged from 110 -130 cm. 4- Total length was 190 cm 5- Total height was 132 cm

3-2-1-3- Components of the prototype: The human power prone cart consists of the main parts frame, quadric bent, two seats, four pedal, two handle bars and transmission system are as followed:

36

1- Frame: The main frame consists nine parts (Figs. 3.1and3.2) which are rectangle shape, it was made from steel as two of the horizontal top tubes (1): were steel tubes 4 cm diameter and 110 cm length to connect forward with head tube (2) and vertical seat tube (3) in the side of the horizontal top tube, and it carry flywheel (4) and a seat (5). Big connected tube: steel tube 7.95 cm diameter and 110-130 cm length link between the two side tubes. Small connected tube (6): steel tube 4 cm diameter and 110-130 cm length, its ends linked a (u) shape parts to allow the vertical movement freedom of the powered prone cart sides. The other parts are supporting with the main frame. That vertical bar (7) supporting with the front corner of the main frame the nearest end of the middle part. These consist three parts: the lower part name is Steering Fork: this part as a (U) shape, was made from steel bar of 30 cm length, 7 cm width and 1 cm thickness and connecting with hub of the front wheel from its lower end and from its upper plate supported the middle part. The middle part was steel tube 4 cm diameter and 37 cm length connected with horizontal top tube, the bottom rectangle bar, handlebars (8) and a steering fork. Also, the two vertical beams (9) supporting at the rear corner of the main frame: steel tube 4 cm diameter and 85 cm length connected with horizontal top tube. 2- Quadric-bent: The quadric-bent consists of four wheels 45 × 11 cm size of each. These wheels are fixed with the body by means of two tubs. These wheels proved

37

successful in most agricultural field conditions and has an increase in the width to depth ratio of the regular tread (R-1) bar lag should improve tread wear characteristics on hard surfaces without seriously affecting the tire's traction performance. 3- Seat: The seat dimensions are 350 × 350 mm and hinder 350 × 350 mm, it made from wood and it was put on the top tube. The most striking feature in the seat is the adjust went of its position for riders in the longitudinal and vertical axes relative to the pedals the seat design was affected by three important followed points, 1. Angle determination. 2. Adjustability solution 3. Weight distribution. To design a comfortable and easily adjustable seat. First the reclining angle at which rider felt relaxed and able to produce as much pedaling power as possible. 4- Pedal: The four bicycle pedals were used to transmit the human motion to the quadric bent by the driving sprocket. Its damnations are 200 mm length and 150 mm width. It was made from rubber.

38

5- Handle Bars: The handle bar was made from steel tube 1.4 cm diameter and 350 mm length. The handle designed to provide a comfortable position to the worker and can control in the height within 6 cm so as not to cause additional strain on the workers. The both end of the tube the rubber tube as a hand. Connected tube steel tube 1.4 cm diameter length of 110-130 cm link between the two units.

39

5

2 1

3

9 4

8

7

6

1 Horizontal Top Tube 4 Flywheel 7 Small Connected Tube 2 Head Tube 5 Seat 8 Steering Fork 3 Vertical Seat Tube 6 Big Connected Tube 9 Middle Part Fig 3.1: Schematic diagram of the human power unit (prototype).

40

Fig. 3.2: The photograph of human powered prone cart.

41

3-2-1-4- Transmission System: The transmission system has two functions in addition to transmitting the power by pedal to the wheel. The first, storage the power by the flywheel. The second, controlling to the speed of machine. The human prone cart transmission system (Fig 3.3) consists of variable pulleys diameter, V- belt, sprockets and chain. The main force can be increased by decreasing the speed rate. The components of the power train designed (Transmission system) can be cleared showing in fig.(3.3). 1 6 2 7 8 3 9

4

10

5 1 Flywheel

6

Driving pulleys

2 Small pulleys

7

Pedal

3 Wheel

8

Big pulleys

4 Steering Fork

9

Driven sprocket

5 Driven sprocket

10 Driven pulleys

Fig. 3.3 Photograph of the power prone cart transmission system.

42

3-2-1-4-1- Variable pulleys and V-belt drive: There are six pulleys designed to transmit the speed of pedal by ratios of (1 to 4.5), (1 to 3.5), (1 to 2.5). The diameter of these pulleys are 210, 160, 110 mm (Fig. 3.4). Therefore, there are two pulleys (270 and 60 mm diameter) designed to transmit the motion from pedal to the flywheel by ratios of (1 to 4.5). To transmit the motion between pulleys, suitable V- belts were used.

Fig. 3.4: The different locally pulley used.

Fig. 3.5: Sketch of transmission system.

3-2-1-4-2- Gears and chain:Two pair of gears and chain were used to transmit the motion between the pulleys and wheel. The first gear specification is 60 mm diameter and 14 teeth, and then the other gear is 180 mm diameter and 42 teeth. The gears specification selected to gave a reduction ratio of (3 to 1). These parts were bought from the local markets. 3-2-1-4-3- Flywheel:Flywheel (Fig 3.5) made of steel of 30 cm diameter and 3 cm thickness. It takes its motion from pedal by two steel pulleys. The flywheel was designed to

43

take its motion from pedal with ratio of 5 to 1. The drive pulley is 27 cm diameter is a drive and the second 6 cm diameter is driven. Then the V-belt was used to transmit the motion between the two pulleys.

3-3- Experimental procedure: 3-3-1- Pre-experimental procedure A pre-experimental study was done to determine the suitable constants of the human power prone cart, which were employed to determine the different redaction ratio R

The speed of pedal ………………………………………..[3-1] The speed of wheel

The variations of the reduction ratio were obtained by using different pulley diameter 110,160,210 mm.

3-3-2- Field experimental design The split split plot design in three replicates was used in this study. The experiments of the human power unit "prone cart" included 162 treatments three reduction ratio (1 : 2.5, 1 : 3.5 and 1 : 4.5),three traction weights in paved road (75, 100 and 125 kg),three traction weights in unpaved road (25, 50 and 75 kg),three drawbar heights (30, 35 and 40 cm), three tire inflation pressure (1.0, 1.5 and 2 bar) and two types of roads (paved Asphalt and unpaved road)each experiment required three plots each of 100 m length.

44

3-3-3- Treatments: Field experimental trails involved the following stages: 1- Road type (S): Paved (S1) and unpaved (S2) road are used to evaluate the prone cart 2- The traction weight (W): a- In paved road the unit power was used to pull the traced weights (Wp 1, Wp2 and Wp3) 125, 100 and 75 kg. b- In unpaved road the unit power was used to pull the traced weights (Wu 1, Wu2 and Wu3) 75, 50 and 25 kg. 3- Tire inflation pressure (P): The tire inflation pressure variable (P1, P2 and P3) of 2, 1.5 and 1 bar in the rear wheels. 4- Drawbar high (H): The drawbar height (H1, H2 and H3) of 40, 35 and 30 cm of the hitching point were used. 5- Redaction ratio (R): The most important factor affecting the drawbar-pull is the redaction ratio. the power unit has three ratios of redactions. The traction force was measured for the designed power unit having ratios of redactions (R 1, R2 and R3) of 1:4.5, 1:3.5 and 1:2.5. Figs. (3.6) and (3.7) shows the experimental design in paved and unpaved roads, respectively of the above variable to test and evaluate the prone cart performance.

45

variables H1

R1 Wp1

Wp2

R2 Wp3

Wp1

Wp2

R3 Wp3

Wp1

Wp2

100

P1 H2 H3 H1 S1 P2 H2 H3 H1 P3 H2 H3 H1 P1 H2 H3 H1 S2 P2 H2 H3 H1 P3 H2 H3 R= S=

Redaction ratio Road type

Wp = traction weight in paved road P = Tire inflation pressure H = Drawbar high

Fig. 3.6: The experimental design in paved road.

46

Wp3

variables H1 P1

R1

R2

R3

Wu1 Wu2 Wu3 Wu1 Wu2 Wu3 Wu1 Wu2 Wu3 100

H2 H3 H1

S1

P2

H2 H3 H1

P3

H2 H3 H1

P1

H2 H3 H1

S2

P2

H2 H3 H1

P3

H2 H3

R= S=

Redaction ratio Road type

Wu = traction weight in unpaved road P = Tire inflation pressure H = Drawbar high

Fig. 3.7: The experimental design in unpaved road.

47

3-4- Instruments 3-4-1- Mechanical dynamometer (double spring balance):Mechanical dynamometer (Fig 3.8) with a double spring of 110 mm length for each, steel discs and a slider were designed to measure traction force. The dynamometer has an accuracy of 1 kg. The spring which shortens under compression represents the value of traction force at the slider.

3-4-2- Stop watch:A stop watch (Fig 3.9) having an accuracy of 0.01 second was used to measure the time during each operation.

Fig. 3.8: Dynamometer (Double spring).

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Fig. 3.9: Stop watch.

3-4-3- Pressure gauge:The pressure gauge (Fig 3.10) is used in this study to measure the rear tire inflation pressure. It is used to adjust the pressure percentage.

Fig. 3.10: Pressure gauge

3-4-4- Road type:In traction experiments two road types were used. Namely, paved (Asphalt) and unpaved roads. The traction characteristics was of (0.4) for coefficient of friction between the wooden trailer and the paved road, and is (0.06) as a value of the factor of rolling resistance for drive-wheel. Whereas it is (0.6) for coefficient of friction and (0.183) as a factor or rolling resistance on the second road type (unpaved road). The values of coefficient of friction and the rolling resistance factor were determined according to Hamaad (1962).

49

3-5- Methods:3-5-1- Traction force measurement by wooden trailer:To test the prone cart traction force the wooden trailer (Fig 3.11) of 770 × 650 mm dimension was designed. Different weights were put in the wooden trailer. The wooden trailer is attached with a hitching system (drawbar pull) by a chain. The drawbar was manufactured locally from steel angle fixed with horizontal points. The draw-bar angle of 1100 mm length, 30 mm width. It is fixed at the rear side of frame back to the prone cart wheel. The drawbar height is variable (300, 350 and 400 mm) from the ground surface.

Fig. 3.11: The wooden trailer

50

3-5-2- Human power unit performance: To evaluate the performance of the designed human power unit (prone cart) the slippage percentage, forward speed and traction force were measured.

3-5-2-1- Determination of forward speed of prone cart: The experimental field more than 120 m long in the first stage was measured. The working race 100 m long has to be measured in the middle of all lengths by marking tow lines, one on the beginning and the other one at the end of 100 m (i.e. 10 m long of the race was left in both the starting or the ending of the run) these 10 m was sufficient to reach the steady state of the tilling speed. The tillage time was computed between the pass of a certain point on the power unit from the line of staring to the pass of the same point at the dead line. The speed was then computed by dividing the 100 m travel distance on its counted time. Forward speed could be calculated from the following equation:

V

L …………………………………………..[3-2] T

Where: V= forward speed (m/sec.) L= distance that the unit made from beginning of the line to end of this line, m T = Time made for this distance, sec

51

3-5-2-2- Determination of slip percentage of prone cart: The slip percent is one of the parameters affecting the horsepower required from the power unit. A marked was put at the drive wheel, and measured the advance of the power unit per ten revolution without any attached weights, also we measured its advanced per ten revolution with the attached weights mentioned before. The experiments were carried out on pave and unpaved road using the wooden trailer using. In every level of attached load the advance of the power unit per ten revolutions of the wheel was determined comparison was made between it and the advance without attached weight. Travel reclusion for any given weight is determined using the following equation. Drive-wheel slippage could be calculated from the following equation, (Barger et. al. 1963)::  R -r  Slip percentage     R 

……………………………[3-3]

Where: R= total drive wheel revolution count to traverse the drawbar runway under load. R r = total drive wheel revolution count to traverse the drawbar test runway

52

3-5-2-3- Determination of traction force of prone cart: For measuring the drawbar pull, the double spring dynamometer that mentioned previously was used. The height of the hitch points were as follows: The power unit (prone cart) hitch points heights = 30, 35 and 40 cm. The wooden trailer hitch point height = 5 cm from the ground. The horizontal distance between the two hitch point = 50 cm. Tan  

difference s between the heights degrees …………………[3-4] horizontal distance

The corrected force = the obtained force Χ cos α

53

4- RESULTS AND DISCUSSIONS 4-1- Machine Performance and Evaluation The tables in appendix presents the data produced for measuring machine performance. The proposed forward speed, slippage and drawbar pull were tested using two roads types (paved (Asphalt) and unpaved road). These parameters were tested at various reduction ratios, traction weights, drawbar heights and tire inflation pressures. The performance criteria may be defined as follows: a) Forward speed. b) Slippage. c) Drawbar pull.

4-1-1-The paved road 4-1-1-1- Forward speed Fig. (4.1) and table (7.1) in appendix shows that the effect of drawbar height on forward speed at three adding weights and three different tire inflation pressures and reduction ratio of (1:4.5). It can be seen that forward speed decreased with increasing the drawbar height, this trend was due to the increase of the moment arm that of the rear wheel axe to the center of gravity distance.

Forward speed was 1.47, 1.45 and 1.43 km/h for drawbar height 30, 35 and 40 cm height from the ground, respectively at traction weight of 75 kg. These results were obtained using tire inflation pressures of 2 bar. The result showed the same trend at traction weight of 100 and 125 kg with reduction ratio of (1:4.5). At tire inflation pressure 1.5 bar. The forward speed was 1.41, 1.35 and 1.33 km/h for drawbar height 30, 35 and 40 cm height with the ground. And at tire inflation pressure 1.0 bar the forward speed were 1.39, 1.341, and 1.3 Km/ hr for drawbar height 30, 35 and 40 cm height at the same conditions. By the increase in tracted weight from 75 to 125 kg the forward speed decreased from 1.47 to 1.27, 1.41 to 1.23 and 1.39 to 1.25 km/h at tire inflation pressure 2, 1.5, 1.0 bar respectively. From theses results it was indicated that, increasing in the drawbar height decreased the forward speed, and with increasing the tracted weights the forward speed decreased also at reduction ratio of 1:4.5.

55

(TIP 2.0 bar) kg 75

kg 100

kg 125

Forward speed (Km/h)

1.5 1.4 1.3 1.2 1.1 1 30


1.5

35

40

(TIP 1.5 bar)

1.4

1.3

1.2

1.1

1 30


1.5

35

40

(TIP 1.0 bar)

1.4

1.3

1.2

1.1

1 30

35 Drawbar height (cm)

40

Fig. (4.1): Effect of drawbar height and adding weights on forward speed at three different tire inflation pressures (TIP) at reduction ratio of (1:4.5).

56

Fig. (4.2) and table (7.1) in appendix shows that the effect of drawbar height on forward speed at three added weights, three different tire inflation pressures and reduction ratio of (1:3.5). Forward speed was 2.57, 2.31 and 2.1 km/h for drawbar height 30, 35 and 40 cm height from the ground, respectively at traction weight of 75 kg. These results were obtained by using tire inflation pressures of 2 bar. The results showed the same trend at traction weights of 100 and 125 kg with reduction ratio of (1:3.5). At tire inflation pressure of 1.5 bar the forward speed was 2.34, 2.12 and 1.88 km/h for the drawbar heights of 30, 35 and 40 cm. At tire inflation pressure of 1.0 bar the forward speeds were 1.43, 1.38 and 1.36 Km/ hr for drawbar height 30, 35 and 40 cm at the same conditions. By the increase in tracted weight from 75 to 125 kg the forward speed decreased from 2.57 to 1.69, 2.34 to 1.58 and 1.43 to 1.29 km/h at tire inflation pressure 2, 1.5, 1.0 bar respectively. From these results it was indicated that, increasing the drawbar height leeds to decrease the forward speed and with increasing the traced weights the forward speed decreased also at redaction ratio of 1:3.5.

57


(TIP 2.0 bar) 2.7 2.6 2.5 2.4 2.3 2.2 2.1 2 1.9 1.8 1.7 1.6 1.5 1.4

kg 75

30 2.4

kg 100

kg 125

35

40

(TIP 1.5 bar)

2.3


2.2 2.1 2 1.9 1.8 1.7 1.6 1.5 1.4 1.3 30


1.5

35

40

(TIP 1.0 bar)

1.4

1.3

1.2

1.1

1 30


40


58

Fig. (4.3) and table (7.1) in appendix shows that the effect of drawbar height on forward speed at three added weights, three different tire inflation pressures and reduction ratio of (1:2.5). Forward speed was 3.7, 3.2 and 2.81 km/h for drawbar height 30, 35 and 40 cm height from the ground, respectively at traction weight of 75 kg. These results were obtained by using tire inflation pressures of 2 bar. The results showed the same trend at traction weights of 100 and 125 kg with reduction ratio of (1:2.5). At tire inflation pressure of1.5 bar the forward speed was 3.3, 2.9 and 2.51 km/h for draw bar heights of 30, 35 and. At tire inflation pressure of1.0 bar the forward speeds were 1.44, 1.41 and 1.4 Km/ hr for the drawbar heights of 30, 35 and 40 cm at the same conditions. By the increase in tracted weight from 75 to 125 kg the forward speed decreased from 3.7 to 2.1, 3.3 to 1.89 and 1.44 to 1.3 km/h at tire inflation pressure 2, 1.5, 1.0 bar respectively. From these results it was indicated that, increasing the drawbar height leeds to decrease the forward speed and with increasing the traced weights the forward speed decreased also at redaction ratio of 1:2.5.

59


(TIP 2.0 bar)

4 3.8 3.6 3.4 3.2 3 2.8 2.6 2.4 2.2 2 1.8 1.6 1.4

kg 75

30

3.4

kg 100

35

kg 125

40

(TIP 1.5 bar)


3.2 3 2.8 2.6 2.4 2.2 2 1.8 1.6 1.4 30


1.5

35

40

(TIP 1.0 bar)

1.45 1.4 1.35 1.3 1.25 1.2 30


40


60

Fig. (4.4) and tabulated in table (7.1) shows the effect of tire inflation pressures on forward speed at three drawbar heights ,three reduction ratios and three traction weights (75, 100 and 125 kg). At traction weight of 75 kg as shown in fig. (4.4 A) The figure indicated that increasing tire inflation pressure increased the forward speed with 1.39, 1.41 and 1.47 km/h for tire inflation pressures of 1.0, 1.5 and 2.0 bar, respectively at 30 cm drawbar height with the ground. These results were obtained by using the reduction ratio of (1:4.5). The result showed that the same trend at 35 and 40 cm drawbar height. Forward speed was 1.43, 2.34 and 2.57 km/h for tire inflation pressures of 1.0, 1.5 and 2.0 bar respectively at reduction ratio (1:3.5). And the forward speed was 1.44, 3.3 and 3.7 km/h for tire inflation pressure of 1.0, 1.5 and 2.0 bar respectively at reduction ratio (1:2.5) with the same conditions. On the other hand increasing the drawbar height from 30 to 40 cm height from the ground decreased the forward speed from 1.39 to 1.3, 1.43 to 1.36 and 1.44 to 1.4 at reduction ratio of 1:4.5, 1:3.5 and 1:2.5 respectively at tire inflation pressure of 1.0 bar. At traction weight 100 kg as shown on fig. (4.4 B) Forward speed was 1.35, 1.38 and 1.39 km/h for tire inflation pressures of 1.0, 1.5 and 2.0 bar, respectively with 30 cm drawbar height. These results were obtained by using the reduction ratio of (1:4.5). The result showed the same trend at 35 and 40 cm drawbar height. Forward speed were 1.39, 1.91 and 2.13km/h for tire inflation pressures of 1.0, 1.5 and 2.0 bar at reduction ratio of (1:3.5) and the forward

61

speed were 1.41, 2.4 and 2.9 km/h for tire inflation pressures of 1.0, 1.5 and 2.0 bar at reduction ratio of (1:2.5) with the same conditions. On the other hand increasing the drawbar height from 30 to 40 cm decreased the average forward speed from 1.35 to 1.195, 1.39 to 1.29 and 1.41 to 1.35 at reduction ratios of 1:4.5, 1:3.5 and 1:2.5 respectively at tire inflation pressure of1.0 bar. At traction weight of 125 kg as shown in fig. (4.4 C) Forward speed was 1.25, 1.23 and 1.27 km/h for tire inflation pressure of 1.0, 1.5 and 2.0 bar, respectively with 30 cm drawbar height. There results were obtained by using the reduction ratio (1:4.5). The result showed the same trend at 35 and 40 cm drawbar height. Forward speed were 1.29, 1.58 and 1.69 km/h for tire inflation pressure of 1.0, 1.5 and 2.0 bar at reduction ratio (1:3.5) and the forward speed were 1.3, 1.89 and 2.1 km/h for tire inflation pressures of 1.0, 1.5 and 2.0 bar at reduction ratio of (1:2.5) with the same conditions. On the other hand increasing the drawbar height from 30 to 40 cm decreased the forward speed from 1.25 to 1.12, 1.29 to 1.16 and 1.3 to 1.23 km/h at reduction ratios of 1:4.5, 1:3.5 and 1:2.5 respectively at tire inflation pressure of 1.0 bar. From these results it was indicated that forward speed increased with increasing the tire inflation pressures, this trend was due to the decrease of surface fraction resistance.

62

30 cm

Forward speed (km/h)

2

35 cm

1.5

40 cm

1.5

35 cm

40 cm

1

1

0.5

0.5

35 cm

40 cm

0.5 0

1 3


30 cm

30 cm

1.5

1

0 1.5

0

1

2 2.5

(RR 1:3.5)

2.5

1.5

2

1 2

(RR 1:3.5)

2

1.5

2

(RR 1:3.5)

1.5

2 1.5 1

1.5 1

1 0.5

0.5

0.5 0

0

1 4 Forward speed (km/h)

(RR 1:4.5)

(RR 1:4.5)

(RR 1:4.5)

1.5

2

0

1 3.5

(RR 1:2.5)

3.5

3

3

2.5

2.5

1.5

2

1 2.5

(RR 1:2.5)

1.5

2

(RR 1:2.5)

2

1.5

2

2 1.5

1

1.5 1

1

0.5

0.5

0.5

0

0 1

1.5 TIP (bar)

2

0

1

1.5 TIP (bar)

(A)

2

(B)

1

1.5 TIP (bar)

2

(C)

Fig. (4.4) Effect of tire inflation pressures (TIP) on forward speed at three drawbar heights and three reduction ratios (RR) at three traction weights (A) 75 kg, (B) 100 kg and (C) 125 kg.

63

4-1-1-2- Slippage Fig. (4.5) and tabulated in table (7.2) in appendix shows that the effect of drawbar height on slippage at three adding weights and three different tire inflation pressures and reduction ratio of (1:4.5). It can be seen that slippage decreased with increasing the drawbar height, and it was found that increasing the drawbar height increased the weight transferred to the rear axle and reaction and this decreased the slip percentage. Slippage was 2.09, 1.09 and 0.96 % for drawbar height 30, 35 and 40 cm height from the ground, respectively at traction weight of 75 kg. These results were obtained by using tire inflation pressures 2 bar. The result showed that the same trend at traction weight of 100 and 125 kg with reduction ratio of (1:4.5). At tire inflation pressure 1.5 bar the slippage was 0.96, 0.83 and 0.6% for drawbar height 30, 35 and 40 cm height with the ground. And at tire inflation pressure 1.0 bar the slippage was 0.81, 0.66 and 0.33 % for drawbar height 30, 35 and 40 cm height at the same conditions. By the increase in tracted weight from 75 to 125 kg the slippage increasing from 2.08597 to 2.71, 0.96 to 1.70and 0.81 to 1.62 at tire inflation pressure 2.0, 1.5, 1.0 bar respectively. From this results it indicate that, at increasing in the drawbar height due to decreasing in the slippage and with increase in tracted weights the slippage increase at in reduction ratio 1:4.5.

64

(TIP 2.0 bar) 3 75

100

125

Slipage %

2.5 2 1.5 1 0.5 0 30

35

40

Fig. (4.5): Effect of drawbar height and adding weights on slippage at three different tire inflation pressures (TIP) at reduction ratio of (1:4.5).

65

Fig. (4.6) and tabulated in table (7.2) in appendix shows that the effect of drawbar height on slippage at three adding weights and three different tire inflation pressures and reduction ratio of (1:3.5). Slippage was 2.55, 1.76 and 1.625 % for drawbar height 30, 35 and 40 cm height from the ground, respectively at traction weight of 75 kg. These results were obtained by using tire inflation pressures 2 bar. The result showed that the same trend at traction weight of 100 and 125 kg with reduction ratio of (1:3.5). At tire inflation pressure 1.5 bar the slippage was 1.93, 1.54 and 1.29 % for drawbar height 30, 35 and 40 cm height with the ground. And at tire inflation pressure 1.0 bar the slippage was 1.9, 1.29 and 1.14 % for drawbar height 30, 35 and 40 cm height at the same conditions. By the increase in tracted weight from 75 to 125 kg the slippage increasing from 2.55 to 3.64, 1.93 to 3.37 and 1.97 to 3.143 at tire inflation pressure 2.0, 1.5, 1.0 bar respectively. From this results it indicate that, at increasing in the drawbar height due to decreasing in the slippage and with increase in tracted weights the slippage increase at in reduction ratio 1:3.5.

66

(TIP 2.0 bar)

4 3.5

kg 75

kg 100

kg 125

Slipage %

3 2.5 2 1.5 1 0.5 0 30 4

35

40

(TIP 1.5 bar)

3.5

Slipage %

3 2.5 2 1.5 1 0.5 0 30 3.5

35

40

(TIP 1.0 bar)

3

Slipage %

2.5 2 1.5 1 0.5 0 30


40


67

Fig. (4.7) and tabulated in table (7.2) in appendix shows that the effect of drawbar height on slippage at three adding weights and three different tire inflation pressures and reduction ratio of (1:2.5). Slippage was 3.05, 2.46 and 2.32 % for drawbar height 30, 35 and 40 cm height from the ground, respectively at traction weight of 75 kg. These results were obtained by using tire inflation pressures 2 bar. The result showed that the same trend at traction weight of 100 and 125 kg with reduction ratio of (1:2.5). At tire inflation pressure 1.5 bar the slippage was 2.98, 2.29 and 2.01 % for drawbar height 30, 35 and 40 cm height with the ground. And at tire inflation pressure 1.0 bar the slippage was 1.29, 1.98 and 1.92 % for drawbar height 30, 35 and 40 cm height at the same conditions. By the increase in tracted weight from 75 to 125 kg the slippage increasing from 3.05 to 4.99, 2.94 to 4.544 and 2.974 to 4.624 at tire inflation pressure 2.0, 1.5, 1.0 bar respectively. From this results it indicate that, at increasing in the drawbar height due to decreasing in the slippage and with increase in tracted weights the slippage increase at in reduction ratio 1:2.5.

68

(TIP 2.0 bar)

5 4.5

kg 75

kg 100

kg 125

4

Slipage %

3.5 3 2.5 2 1.5 1 0.5 0 30 6

35

40

(TIP 1.5 bar)

5

Slipage %

4 3 2 1 0 30

5

35

40

(TIP 1.0 bar)

4.5 4

Slipage%

3.5 3 2.5 2 1.5 1 0.5 0 30


40


69

Fig. (4.8) and tabulated in table (7.2) shows the effect of tire inflation pressures on slippage at three drawbar heights ,three reduction ratios and three traction weights (75, 100 and 125 kg). At traction weight of 75 kg as shown on fig. (4.8 A) The figure indicated that increasing tire inflation pressure increased the slip percentage with 0.81, 0.96 and 2.09% for tire inflation pressures of 1.0, 1.5 and 2.0 bar, respectively at 30 cm drawbar height with the ground. These results were obtained by using the reduction ratio of (1:4.5). The result showed that the same trend at 35 and 40 cm drawbar height. Slippage was 1.9, 1.93 and 2.55% for tire inflation pressure of 1.0, 1.5 and 2.0 bar respectively at reduction ratio of (1:3.5). And the slippage was 2.97, 2.94 and 3.05 % for tire inflation pressure of 1.0, 1.5 and 2.0 bar respectively at reduction ratio of (1:2.5) with the same conditions. On the other hand increase the drawbar height from 30 to 40 cm height decreased the slippage from 0.81 to 0.33, 1.9 to 1.14 and 2.97 to 1.92 % at reduction ratio 1:4.5, 1:3.5 and 1:2.5 respectively at tire inflation pressure of 1.0 bar. At traction weight 100 kg as shown on fig. (4.8 B) slippage was 0.93, 1.22 and 2.27 % for tire inflation pressure of 1.0, 1.5 and 2.0 bar, respectively with 30 cm drawbar height. These results were obtained by using the reduction ratio of (1:4.5). The result showed the same trend at 35 and 40 cm drawbar height. Slippage was 2.22, 2.5 and 3.04 % for tire inflation pressure of 1.0, 1.5 and 2.0 bar at reduction ratio (1:3.5) and the slippage was 3.48, 3.74 and 3.85% for tire inflation pressures of 1.0, 1.5 and 2.0 bar at reduction ratio of (1:2.5) with the same conditions.

70

On the other hand increasing the drawbar height from 30 to 40 cm decreased the average slippage from 0.93 to 0.42, 2.22 to 1.14 and 3.48 to 1.82% at reduction ratios of 1:4.5, 1:3.5 and 1:2.5 respectively at tire inflation pressure of 1.0 bar. At traction weight of 125 kg as shown in fig. (4.8 C) Slippage was 1.62, 1.7 and 2.71 % for tire inflation pressure of 1.0, 1.5 and 2.0 bar, respectively with 30 cm drawbar height. There results were obtained by using the reduction ratio (1:4.5). The result showed the same trend at 35 and 40 cm drawbar height. Slippage was 3.143, 3.37 and 3.64 % for tire inflation pressures of 1.0, 1.5 and 2.0 bar at reduction ratio of (1:3.5) and the slippage was 4.63, 4.99 and 4.54% for tire inflation pressures of 1.0, 1.5 and 2.0 bar at reduction ratio of (1:2.5) with the same conditions. On the other hand increasing the drawbar height from 30 to 40 cm decreased the slippage from 1.62 to 0.64, 3.143 to 1.63 and 4.63 to 2.65 % at reduction ratios of 1:4.5, 1:3.5 and 1:2.5 respectively at tire inflation pressure of 1.0 bar. From these results it was found that increasing the drawbar height increased the weight transferred to the rear axle and resulted in higher rear axle reaction and this decreased the slip percentage. The lower curves were due to the lower tire inflation pressure which led to larger contact surface with the ground i.e. decreasing the slip. On the other side the higher slip curves were due to the higher tire inflation pressures, which decreased the contact surface area i.e. led to higher slip percentage resulted.

71

2.5

(RR 1:4.5) 30 cm

Slipage %

2

35 cm

(RR 1:4.5)

2.5

(RR 1:4.5) 3

30 cm

40 cm

35 cm

40 cm

30 cm

35 cm

40 cm

2.5

2

2

1.5

1.5

1.5

1

1

1

0.5

0.5

0

0

0

1 3

1.5

2

(RR 1:3.5)

1

3.5

2.5

Slipage %

0.5

1.5

4

(RR 1:3.5)

1.5

2

(RR 1:3.5)

3.5

3

2

1

2

3

2.5

2.5

2

1.5

2

1.5

1

1.5

1 1

0.5

0.5

0

0.5

0

1 3.5

1.5

2

0

1 4.5

(RR 1:2.5)

1.5

2

(RR 1:2.5)

4

3

1

6

1.5

2

(RR 1:2.5)

5

3.5 Slipage %

2.5

4

3

2

2.5

1.5

2

3 2

1.5

1

1

1

0.5 0.5

0

0

0

1

1.5 TIP (bar)

2

(A)

1

1.5 TIP (bar)

(B)

2

1

1.5

2

TIP (bar)

(C)

Fig. (4.8) Effect of tire inflation pressures (TIP) on slippage at three drawbar heights and three reduction ratios (RR) at three traction weights (A) 75 kg, (B) 100 kg and (C) 125 kg.

72

4-1-1-3- Drawbar pull Fig. (4.9) and table (7.3) in appendix shows the effect of drawbar height on drawbar pull at three adding weights and three different tire inflation pressures at reduction ratio of (1:4.5). It can be seen that drawbar pull increased with increasing the drawbar height, this increase is attributed to the weight transferred due to the increase of drawbar height, and this trend was due to the increase of the moment arm to that of the rear wheel axe to the center of gravity distance which affect the moment of the tractor weight. Drawbar pull was 35, 40 and 45 kg for drawbar height of 30, 35 and 40 cm, respectively at traction weight of 75 kg. These results were obtained using tire inflation pressure 2 bar. The result showed that the same trend at traction weights of 100 and 125 kg with reduction ratio of (1:4.5). At tire inflation pressure of 1.5 bar the drawbar pull was 40, 45 and 50 kg for drawbar heights of 30, 35 and 40 cm. And at tire inflation pressure of 1.0 bar, the drawbar pull was 42.5, 50 and 55 kg for drawbar heights of 30, 35 and 40 cm at the same conditions. By the increase in tracted weight from 75 to 125 kg the drawbar pull increased from 35 to 50, 40 to 55 and 42.5 to 65 Kg at tire inflation pressures of 2, 1.5, 1.0 bar respectively. From these results it was indicated that, at increasing in the drawbar height due to increase in drawbar pull and with the increase in tracted weights the drawbar pull increased also at reduction ratio of 1:4.5.

73

(TIP 2.0 bar)

70 75

100

125

Drawbar pull (Kgf)

60 50 40 30 20 10 0 30

35

40

Fig. (4.9): Effect of drawbar height and adding weights on drawbar pull at three different tire inflation pressures (TIP) at reduction ratio of (1:4.5).

74

Fig. (4.10) and table (7.3) in appendix shows the effect of drawbar height on drawbar pull at three adding weights and three different tire inflation pressures at reduction ratio of (1:3.5). Drawbar pull was 32.5, 37.5 and 42.5 kg for drawbar heights of 30, 35 and 40 cm, respectively at traction weight of 75 kg. These results were obtained at tire inflation pressure 2 bar. The result showed the same trend at traction weights of 100 and 125 kg with reduction ratio of (1:3.5). At tire inflation pressure of 1.5 bar the drawbar pull was 35.5, 42.25 and 45.25 kg for drawbar heights of 30, 35 and 40 cm. And at tire inflation pressure of 1.0 bar the drawbar pull was 40, 45.25 and 55.5 kg for drawbar heights of 30, 35 and 40 cm height at the same conditions. By the increase in tracted weight from 75 to 125 kg the drawbar pull increasing from 32.5 to 50, 35.5 to 52.5 and 40 to 60 kg at tire inflation pressures of 2, 1.5, 1.0 bar respectively. From these results it was indicated that, at increasing in the drawbar height due to increase in drawbar pull and with the increase in tracted weights the drawbar pull increased also at reduction ratio of 1:3.5.

75

(TIP 2.0 bar) 70 kg 75

kg 100

kg 125

Drawbar pull (Kgf)

60 50 40 30 20 10 0 30 70

35

40

(TIP 1.5 bar)

Drawbar pull (Kgf)

60 50 40 30 20 10 0 30 80

35

40

(TIP 1.0 bar)

Drawbar pull (Kgf)

70 60 50 40 30 20 10 0 30


40


76

Fig. (4.11) and tabulated in table (7.3) in appendix shows the effect of drawbar height on drawbar pull at three adding weights and three different tire inflation pressures and reduction ratio of (1:2.5). Drawbar pull was 30, 35 and 40 kg for drawbar heights of 30, 35 and 40 cm, respectively at traction weight of 75 kg. These results were obtained by using tire inflation pressure of 2 bar. The result showed the same trend at traction weight of 100 and 125 kg with reduction ratio of (1:2.5). At tire inflation pressure of 1.5 bar the drawbar pull was 32.5, 37.5 and 42.5 kg for drawbar heights of 30, 35 and 40 cm. And at tire inflation pressure of 1.0 bar the drawbar pull were 35, 42.5 and 52.5 kg for drawbar heights of 30, 35 and 40 cm height at the same conditions. By the increase in tracted weight from 75 to 125 kg the drawbar pull increased from 30 to 50, 32.5 to 52.5 and 35 to 57.5 kg at tire inflation pressures of 2, 1.5, 1.0 bar respectively. From these results it was indicated that, at increasing in the drawbar height due to increase in drawbar pull and with the increase in tracted weights the drawbar pull increased also at reduction ratio of 1:2.5.

77

(TIP 2.0 bar) 70

kg 75

kg 100

kg 125

Drawbar pull (Kgf)

60 50 40 30 20 10 0 30

70

35

40

(TIP 1.5 bar)

Drawbar pull (Kgf)

60 50 40 30 20 10 0 30 80

35

40

(TIP 1.0 bar)

Drawbar pull (Kgf)

70 60 50 40 30 20 10 0 30


40


78

Fig. (4.12) and table (7.3) shows the effect of tire inflation pressures on drawbar pull at three drawbar heights ,three reduction ratios and three traction weights (75, 100 and 125 kg). At traction weight of 75 kg as shown in fig. (4.12 A) it was indicated that increasing tire inflation pressure decreased the drawbar pull to 42.5, 40 and 35 kg for tire inflation pressure of 1.0, 1.5 and 2.0 bar, respectively at 30 cm drawbar height from the ground. These results were obtained by using the reduction ratio of (1:4.5). The result showed the same trend at 35 and 40 cm drawbar height. Drawbar pull was 40, 35.5 and 32.5 kg for tire inflation pressures of 1.0, 1.5 and 2.0 bar at reduction ratio of (1:3.5). And the drawbar pulls were 35, 32.5 and 30 kg for tire inflation pressures of 1.0, 1.5 and 2.0 bar at reduction ratio of (1:2.5) with the same conditions. On the other hand increasing the drawbar height from 30 to 40 cm increased the drawbar pull from 42.5 to 55, 40 to 55.5 and 30 to 52.5 kg at reduction ratios of 1:4.5, 1:3.5 and 1:2.5 respectively at tire inflation pressure of 1.0 bar. At traction weight 100 kg as shown on fig. (4.12 B) drawbar pull was 45, 45 and 40 kg for tire inflation pressure of 1.0, 1.5 and 2.0 bar, respectively with 30 cm drawbar height. These results were obtained using reduction ratio of (1:4.5). The result showed the same trend at 35 and 40 cm drawbar height. Drawbar pull was 42.5, 40 and 37.5 kg for tire inflation pressure of 1.0, 1.5 and 2.0 bar at reduction ratio of (1:3.5). The drawbar pull was 37.5, 35 and 35 kg at tire inflation pressures of 1.0, 1.5 and 2.0 bar at reduction ratio of (1:2.5) with

79

the same conditions. On the other hand increasing the drawbar height from 30 to 40 cm increased the average drawbar pull from 45 to 70, 42.5 to 65 and 37.5 to 60 kg at reduction ratios of 1:4.5, 1:3.5 and 1:2.5 respectively at tire inflation pressure of 1.0 bar. At traction weight of 125 kg as shown on fig. (4.12 C) the drawbar pull was 65, 55 and 50 kg for tire inflation pressures of 1.0, 1.5 and 2.0 bar, respectively at 30 cm drawbar height. There results were obtained using reduction ratio of (1:4.5). The result showed the same trend at 35 and 40 cm drawbar height. Drawbar pull were 60, 52.5 and 50 kg for tire inflation pressures of 1.0, 1.5 and 2.0 bar at reduction ratio of (1:3.5). The drawbar pull were 57.5, 52.5 and 50 kg for tire inflation pressures of 1.0, 1.5 and 2.0 bar at reduction ratio of (1:2.5) with the same conditions. On the other hand increasing the drawbar height from 30 to 40 cm increased the drawbar pull from 65 to 80, 60 to 75 and 57.5 to 70 kg at reduction ratios of 1:4.5, 1:3.5 and 1:2.5 respectively at tire inflation pressure of 1.0 bar. From these results it was found that increasing the drawbar height increased the weight transferred to the rear axle and resulted in higher rear axle reaction which led to larger contact surface and this increased the drawbar pull.

80

Drawbar pull (Kgf)

60

30 cm

35 cm

80 40 cm

90 30 cm

70

50

60

40

50

35 cm

40 cm

30 cm

80

35 cm

40 cm

70 60 50

40

30

40

30

30

20 20

10

10

0

0

1

60

1.5

2

20 10 0

1

70

(RR 1:3.5)

1.5

2

1.5

2

(RR 1:3.5)

70 60

50

40

1

80

(RR 1:3.5)

60

50 Drawbar pull (Kgf)

(RR 1:4.5)

(RR 1:4.5)

(RR 1:4.5)

50

40

30

40

30 30

20

20

10

20

10

0

10

0

1

1.5

2

0

1

70

60

1.5

2

80

(RR 1:2.5)

(RR 1:2.5)

1

60

70

50

60

1.5

2

(RR 1:2.5)

Drawbar pull (Kgf)

50 40

50

40

40

30 30

30

20

20

10

20

10

0

10 0

0

1

1.5 TIP (bar)

2

1

(A)

1.5 TIP (bar)

(B)

2

1

1.5 TIP (bar)

2

(C)

Fig. (4.12) Effect of tire inflation pressures (TIP) on drawbar pull at three drawbar heights and three reduction ratios (RR) at three traction weights (A) 75 kg, (B) 100 kg and (C) 125 kg.

81

4-1-1-4- Optimum operational conditions at paved road. The maximum forward speed of the power unit prone cart was 3.7 km/h, obtained at reduction ratio of (1:2.5), tire inflation pressure of 2 bar, traction weight 75 kg and drawbar height 30 cm. At this condition the value of slippage recorded 3.05%, and the value of drawbar pull was 30 kg. On the other hand the best value as minimum slippage of the power unit was 0.33 %, obtained at reduction ratio of (1:4.5), tire inflation pressure of 1.0 bar, traction weight 75 kg and drawbar height 40 cm. While the forward speed was 1.3 km/h and drawbar pull was 55 kg were recorded at this condition. The maximum drawbar pull of the power unit prone cart was 80 kg, obtained at reduction ratio of (1:4.5), tire inflation pressure of 1.0 bar, traction weight of 125 kg and drawbar height of 40 cm. While the forward speed was 1.12 km/h as minimum value and slippage was 0.64% was recorded at this condition.

82

4-1-2-The unpaved road 4-1-2-1- Forward speed Fig. (4.13) and table (7.4) in appendix shows the effect of drawbar height on forward speed at three adding weights, three different tire inflation pressures and reduction ratio of (1:4.5). It can be seen that forward speed decreased with increasing the drawbar height, this trend was due to the increase of the moment arm which transferred the weight to the rear wheel axe across into distance from the center of gravity distance. The forward speed was 1.14, 1.04 and 0.99 km/h for drawbar height 30, 35 and 40 cm, respectively at traction weight of 25 kg. These results were obtained by using tire inflation pressures of 2 bar. The result showed that the same trend at traction weight of 50 and 75 kg with a reduction ratio of (1:4.5). At tire inflation pressure of 1.5 bar the forward speed was 1.01, 0.99 and 0.9 km/h for drawbar heights of 30, 35 and 40 cm. And at tire inflation pressure of 1.0 bar the forward speeds were 0.99, 0.94 and 0.87 Km/ hr for drawbar heights of 30, 35 and 40 cm at the same conditions. By the increase in tracted weight from 25 to 75 kg the forward speed decreased from 1.14 to 0.89, 1.01 to 0.84 and 0.99 to 0.81 km/h at tire inflation pressures of 2, 1.5, 1.0 bar respectively. From these results it was indicated that, at increasing the drawbar height leads to decrease the forward speed, increasing the in tracted weights the forward speed decreased also at reduction ratio of 1:4.5.

83

(TIP 2.0 bar) 1.2


kg 25

kg 50

kg 75

1.1 1 0.9 0.8 0.7 0.6 0.5 30 1.1

35

40

(TIP 1.5 bar)


1 0.9 0.8 0.7 0.6 0.5 30


1.1

35

40

(TIP 1.0 bar)

1 0.9 0.8 0.7

c

0.6 0.5 30


40


84

Fig. (4.14) and table (7.4) in appendix shows the effect of drawbar height on forward speed at three adding weights, three different tire inflation pressures and reduction ratio of (1:3.5). Forward speed was 2.43, 2.33 and 2.14 km/h for drawbar heights of 30, 35 and 40 cm, respectively at traction weight of 25 kg. These results were obtained using tire inflation pressure of 2 bar. The result showed that the same trend at traction weight of 50 and 75 kg with reduction ratio of (1:3.5). At tire inflation pressure 1.5 bar the forward speeds were 2.11, 1.92 and 1.795 km/h for drawbar heights of 30, 35 and 40 cm. At tire inflation pressure 1.0 bar the forward speeds were 1.97, 1.66 and 1.47 Km/ hr for drawbar heights of 30, 35 and 40 cm height at the same conditions. By the increase in tracted weight from 25 to 75 kg the forward speed decreased from 2.43 to 1.84, 2.11 to 1.69 and 1.97 to 1.42 km/h at tire inflation pressures of 2, 1.5, 1.0 bar respectively. From these results it was indicated that, at increasing the drawbar height leads to decrease the forward speed, increasing the in tracted weights the forward speed decreased also at reduction ratio of 1:3.5.

85

(TIP 2.0 bar)

2.6


2.4

kg 25

kg 50

kg 75

2.2 2 1.8 1.6 1.4 1.2 1 30

2.6

35

40

(TIP 1.5 bar)


2.4 2.2 2 1.8 1.6 1.4 1.2 1 30


3

35

40

(TIP 1.0 bar)

2.5 2

1.5 1 0.5 30


40


86

Fig. (4.15) and table (7.4) in appendix shows the effect of drawbar height on forward speed at three adding weights, three different tire inflation pressures and reduction ratio of (1:2.5). Forward speeds were 3.76, 3.6 and 3.3 km/h for drawbar heights of 30, 35 and 40 cm, respectively at traction weight of 25 kg. These results were obtained by using tire inflation pressure of 2 bar. The result showed that the same trend at traction weights of 50 and 75 kg with reduction ratio of (1:2.5). At tire inflation pressure of 1.5 bar the forward speed were 3.2, 2.82 and 2.67 km/h for drawbar heights of 30, 35 and 40 cm height with the ground. And at tire inflation pressure of 1.0 bar the forward speeds were 2.93, 2.37 and 2.02 Km/ hr for drawbar heights of 30, 35 and 40 cm height at the same conditions. By the increase in tracted weight from 25 to 75 kg the forward speed decreased from 3.76 to 2.8, 3.2 to 2.54 and 2.93 to 2.02 km/h at tire inflation pressures of 2, 1.5, 1.0 bar respectively. From these results it was indicated that, at increasing the drawbar height leads to decrease the forward speed, increasing the in tracted weights the forward speed decreased also at reduction ratio of 1:2.5.

87

(TIP 2.0 bar) kg 25


4

kg 50

kg 75

3.5 3 2.5 2 1.5 1 0.5 30 3.5

35

40

(TIP 1.5 bar)


3.2 2.9 2.6 2.3 2 1.7 1.4 1.1 0.8 0.5 30


3.5

35

40

(TIP 1.0 bar)

3 2.5 2 1.5 1 0.5 30


40


88

Fig. (4.16) and table (7.4) shows the effect of tire inflation pressures on forward speed at three drawbar heights ,three reduction ratios and three traction weights of (25, 50 and 75 kg). At traction weight of 25 kg as shown on fig. (4.16 A) The figure indicated that increasing tire inflation pressure increased the forward speeds to, 0.99, 1.01 and 1.14 km/h for tire inflation pressures of 1.0, 1.5 and 2.0 bar, respectively at 30 cm drawbar height. These results were obtained by using the reduction ratio of (1:4.5). The results showed the same trend at 35 and 40 cm drawbar height. Forward speed was 1.97, 2.11 and 2.43 km/h for tire inflation pressure of 1.0, 1.5 and 2.0 bar at reduction ratio of (1:3.5). And the forward speed was 2.93, 3.2 and 3.76 km/h for tire inflation pressures of 1.0, 1.5 and 2.0 bar at reduction ratio (1:2.5) with the same conditions. On the other hand increasing the drawbar height from 30 to 40 cm height decreased the forward speed from 0.99 to 0.87, 1.97 to 1.472 and 2.93 to 2.02 at reduction ratios of 1:4.5, 1:3.5 and 1:2.5 respectively at tire inflation pressure 1.0 bar. At traction weight 50 kg as shown in fig. (4.16 B) Forward speeds were 0.86, 0.9 and 0.93 km/h for tire inflation pressures of 1.0, 1.5 and 2.0 bar, respectively with 30 cm drawbar height. These results were obtained by using the reduction ratio of (1:4.5). The result showed the same trend at 35 and 40 cm drawbar height. Forward speeds were 1.59, 1.89 and 2.02 km/h for tire inflation pressures of 1.0, 1.5 and 2.0 bar at reduction ratio of (1:3.5) The forward speeds

89

were 2.32, 2.86 and 3.1 km/h for tire inflation pressures of 1.0, 1.5 and 2.0 bar at reduction ratio of (1:2.5) with the same conditions. On the other hand increasing the drawbar height from 30 to 40 cm height from the land decreased the average forward speed from 0.86 to 0.81, 1.59 to 1.36 and 2.32 to 1.89 at reduction ratios of 1:4.5, 1:3.5 and 1:2.5 respectively at tire inflation pressure of 1.0 bar. At traction weight 75 kg as shown on fig. (4.16 C) Forward speeds were 0.81, 0.84 and 0.89 km/h for tire inflation pressures of 1.0, 1.5 and 2.0 bar, respectively with 30 cm drawbar height. These results were obtained by using the reduction ratio of (1:4.5). The result showed the same trend at 35 and 40 cm drawbar height. Forward speeds were 1.41, 1.69 and 1.84 km/h for tire inflation pressures of 1.0, 1.5 and 2.0 bar at reduction ratio of (1:3.5) and the forward speed were 2.02, 2.54 and 2.8 km/h for tire inflation pressures of 1.0, 1.5 and 2.0 bar at reduction ratio of (1:2.5) with the same conditions. On the other hand increasing the drawbar height from 30 to 40 cm decreased the forward speeds from 0.81 to 0.69, 1.41 to 1.27 and 2.02 to 1.82 km/h at reduction ratios of 1:4.5, 1:3.5 and 1:2.5 respectively at tire inflation pressure of 1.0 bar. From these results it was indicated that forward speed increased with increasing the tire inflation pressure, this trend was due to the leas contact area and the decrease of surface fraction resistance.

90

(RR 1:4.5)

(RR 1:4.5) (RR 1:4.5) 30 cm


1.2

35 cm

1

1 0.8 0.6 0.4 0.2 0 1

3

30 cm

1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0

40 cm

1.5

40 cm

30 cm

35 cm

40 cm

0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0

1

2

2.5

(RR 1:3.5)

35 cm

1.5

2

1

2

(RR 1:3.5)

2

(RR 1:3.5)

1.5


1.8

2.5

2

1.6 1.4

2

1.5

1.2

1

0.8

1.5

1

1

0.6

0.5

0.5

0.4 0.2

0

0

1 4

1.5

2 3.5

(RR 1:2.5)

3.5 Forward speed (km/h)

0

1

1.5

2

3

(RR 1:2.5)

3

3

1

1.5

2

(RR 1:2.5)

2.5

2.5

2

2.5

2

2

1.5

1.5

1.5

1

1

0.5

0.5

1 0.5

0 1

1.5 TIP (bar)

2

0

0 1

(A)

TIP1.5 (bar)

(B)

2

1

1.5 TIP (bar)

2

(C)

Fig. (4.16) Effect of tire inflation pressures (TIP) on forward speed at three drawbar heights and three reduction ratios (RR) at three traction weights (A) 25 kg, (B) 50 kg and (C) 75 kg.

91

4-1-2-2- Slippage Fig. (4.17) and table (7.5) in appendix shows that the effect of drawbar height on slippage at three adding weights, three different tire inflation pressures and reduction ratio of (1:4.5). It can be seen that the slippage decreased with increasing the drawbar height, and increasing the drawbar height increased the weight transferred to the rear axle and its reaction which decreased the slip percentage. Slip percentages were 3.62, 3.13 and 2.11 % for drawbar heights of 30, 35 and 40 cm, respectively at traction weight of 25 kg. These results were obtained using tire inflation pressure 2 bar. The result showed the same trend at traction weights of 50 and 75 kg with reduction ratio of (1:4.5). At tire inflation pressure of 1.5 bar the slip percentages were 3.03, 2.11 and 1.98 % for drawbar heights of 30, 35 and 40 cm. At tire inflation pressure of 1.0 bar the slip percentages values were 2.11, 1.67 and 1.12 % for drawbar heights of 30, 35 and 40 cm at the same conditions. By the increase in tracted weights from 25 to 75 kg the slippage increased from 3.2 to 5.62, 3.03 to 4.91 and 2.11 to 3.66 at tire inflation pressures of 2.0, 1.5 and 1.0 bar respectively. From these results it was indicated that, increasing the drawbar height leads to decreasing of the slippage and with increasing in tracted weights the slippage increased at reduction ratio of 1:4.5.

92

(TIP 2.0 bar) 6

kg 25

kg 50

kg 75

Slipage %

5 4 3 2 1 0 30 6

35

40

(TIP 1.5 bar)

5

Slipage %

4 3 2 1 0 30

4

35

40

(TIP 1.0 bar)

3.5

Slipage %

3 2.5 2 1.5 1 0.5 0 30


40


93

Fig. (4.18) and table (7.5) in appendix shows that the effect of drawbar height on slippage at three adding weights, three different tire inflation pressures and reduction ratio of (1:3.5). Slippage values were 5.51, 4.27 and 3.57 % for drawbar heights of 30, 35 and 40 cm, respectively at traction weight of 25 kg. These results were obtained using tire inflation pressure 2 bar. The result showed the same trend at traction weights of 50 and 75 kg with reduction ratio of (1:3.5). At tire inflation pressure 1.5 bar the slippage value were 4.33, 3.8 and 2.67% for drawbar heights of 30, 35 and 40 cm. At tire inflation pressure 1.0 bar the slippage values were 3.92, 2.93 and 2.44 % for drawbar heights of 30, 35 and 40 cm at the same conditions. By the increase in tracted weights from 25 to 75 kg the slippage increased from 5.51 to 7.76, 4.33 to 6.48 and 3.92 to 5.797 at tire inflation pressures of 2.0, 1.5, 1.0 bar respectively. From these results it was indicated that, increasing the drawbar height leads to decreasing of the slippage and with increasing the tracted weights the slippage increased at reduction ratio of 1:3.5.

94

9

(TIP 1.5 bar)

8 7

Slipage %

6 5 4 3 2 1 0 30 9

35

40

(TIP 1.0 bar)

8

Slipage %

7 6 5 4 3 2 1 0 30


95

40

Fig. (4.18): Effect of drawbar height and adding weights on slippage at three different tire inflation pressures (TIP) at reduction ratio of (1:3.5). Fig. (4.19) and table (7.5) in appendix shows the effect of drawbar height on slippage at three adding weights, three tire inflation pressures and reduction ratio of (1:2.5). Slippage values were 7.41, 5.49 and 5.03% for drawbar heights of 30, 35 and 40 cm, respectively at traction weight of 25 kg. These results were obtained using tire inflation pressure 2 bar. The result showed the same trend at traction weights of 50 and 75 kg with reduction ratio of (1:2.5). At tire inflation pressure 1.5 bar the slippage values were 5.73, 5.41 and 3.76 % for drawbar heights of 30, 35 and 40 cm. At tire inflation pressure 1.0 bar the slippage values were 5.62, 4.19 and 3.35% for drawbar heights of 30, 35 and 40 cm at the same conditions. By the increase in tracted weight from 25 to 75 kg the slippage increased from 7.41 to 9.91, 5.73 to 8.06 and 5.62 to 7.93 at tire inflation pressures of 2.0, 1.5, 1.0 bar respectively. From these results it was indicated that, increasing the drawbar height leads to decreasing of the slippage and with increasing in tracted weights the slippage increased at reduction ratio of 1:2.5.

96

12

(TIP 2.0 bar) kg 25

10

kg 50

kg 75

Slipage %

8 6 4 2 0 30 9

35

40

(TIP 1.5 bar)

8 7

Slipage %

6 5 4 3 2 1 0 30 9

35

40

(TIP 1.0 bar)

8

Slipage %

7 6 5 4 3 2 1 0 30

35

40

Drawbar height (cm)


97

Fig. (4.20) and table (7.5) in appendix show the effect of tire inflation pressures on slippage at three drawbar heights ,three reduction ratios and three traction weights (25, 50 and 75 kg). At traction weight of 25 kg as shown on fig. (4.20 A) it was indicated that increasing in tire inflation pressure increased the slippage to 2.11, 3.03 and 3.62% for tire inflation pressures of 1.0, 1.5 and 2.0 bar, respectively at 30 cm drawbar height. These results were obtained using reduction ratio of (1:4.5). The results showed that the same trend was noticed at 35 and 40 cm drawbar height. Slippage values were 3.92, 4.33 and 5.51 % for tire inflation pressures of 1.0, 1.5 and 2.0 bar at reduction ratio of (1:3.5). And the slippage values were 5.62, 5.73 and 7.41% for tire inflation pressures of 1.0, 1.5 and 2.0 bar at reduction ratio of (1:2.5) with the same conditions. On the other hand increasing the drawbar height from 30 to 40 cm decreased the slippage from 2.11 to 1.12, 3.92 to 2.44 and 5.62 to 3.35 % at reduction ratios of 1:4.5, 1:3.5 and 1:2.5 respectively at tire inflation pressure of 1.0 bar. At traction weight of 50 kg as shown in fig. (4.20 B) slippage values were 2.64, 3.27 and 4.05 % for tire inflation pressures of 1.0, 1.5 and 2.0 bar, respectively with 30 cm drawbar height. These results were obtained using the reduction ratio of (1:4.5). The result showed the same trend was noticed at 35 and 40 cm drawbar height. Slippage values were 4.67, 5.63 and 6.31 % for tire inflation pressures of 1.0, 1.5 and 2.0 bar at reduction ratio of (1:3.5) and the slippage values were 6.69, 7.98 and 8.57 % for tire inflation pressures of 1.0, 1.5 and 2.0 bar at reduction ratio of (1:2.5) with the same conditions.

98

On the other hand increasing the drawbar height from 30 to 40 cm decreased the average slippage from 2.64 to 2.34, 4.67 to 3.42 and 6.69 to 4.496% at reduction ratios of 1:4.5, 1:3.5 and 1:2.5 respectively at tire inflation pressure of 1.0 bar. At traction weight 75 kg as shown on fig. (4.20 C) slippage values were 3.66, 4.91 and 5.62 % for tire inflation pressures of 1.0, 1.5 and 2.0 bar, respectively with 30 cm drawbar height. These results were obtained using the reduction ratio of (1:4.5). The result showed the same trend was noticed at 35 and 40 cm drawbar height. Slippage were 5.797, 6.48 and 7.76 % for tire inflation pressures of 1.0, 1.5 and 2.0 bar at reduction ratio of (1:3.5) and the slippage were 7.93, 8.06 and 9.91 % for tire inflation pressures of 1.0, 1.5 and 2.0 bar at reduction ratio of (1:2.5) with the same conditions. On the other hand increasing the drawbar height from 30 to 40 cm decreased the slippage from 3.66 to 3.1, 5.797 to 4.26 and 7.93 to 5.41 % at reduction ratios of 1:4.5, 1:3.5 and 1:2.5 respectively at tire inflation pressure of 1.0 bar. From these results it was found that increasing the drawbar height increased the weight transferred to the rear axle and resulted in higher rear axle reaction and this decreased the slip percentage the lower curves were due to the lower tire inflation pressure which led to larger contact surface area i.e. decreasing the slip, while on the other side the higher slip curves were due to the higher tire inflation pressures, which decreased the contact surface area with the ground.

99

(RR 1:4.5)

(RR 1:4.5) 4

30 cm

35 cm

40 cm

30 cm

4

3.5

35 cm

6

40 cm

3

2.5

30 cm

35 cm

40 cm

5

3.5

3 Slipage %

(RR 1:4.5)

4.5

4

2.5

2 1.5

2

3

1.5

2

1

1

0.5

0.5

1

0

0

0

1

1.5

2

1

1

2

1.5

9

7

6

1.5

(RR 1:3.5)

(RR 1:3.5)

(RR 1:3.5)

2

8

6 7

5

Slipage %

5

6

4 3

4

5

3

4 3

2

2 2

1

1

0

0

1

8

1.5

2

1 0

1

2

1.5

2

(RR 1:2.5)

(RR 1:2.5)

8

7

1

12

9

(RR 1:2.5)

1.5

10

7

6

8

Slipage %

6

5

5

6

4

4

3

3

2

2

1

1

4

2

0

0 1

1.5 TIP (bar)

2

1

(A)

1.5 TIP (bar)

(B)

2

0 1

1.5 TIP (bar)

2

(C)

Fig. (4.20) Effect of tire inflation pressures (TIP) on slippage at three drawbar heights and three reduction ratios (RR) at three traction weights (A) 25 kg, (B) 50 kg and (C) 75 kg.

100

4-1-2-3- Drawbar pull Fig. (4.21) and table (7.6) in appendix shows that the effect of drawbar height on drawbar pull at three added weights, three tire inflation pressures and reduction ratio of (1:4.5). It can be seen that drawbar pull increased with increasing the drawbar height, this increase is attributed to the weight transferred due to the increase of drawbar height, and this trend was due to the increase of the moment arm against that of the rear wheel axe to the center of gravity distance. Drawbar pull values were 15, 20 and 30 kg for drawbar heights of 30, 35 and 40 cm, respectively at traction weight of 25 kg. These results were obtained using tire inflation pressure 2 bar. The results showed the same trend at traction weights of 50 and 75 kg with reduction ratio of (1:4.5). At tire inflation pressure of 1.5 bar the drawbar pull values were 17.5, 22.5 and 32.5 kg for drawbar heights of 30, 35 and 40 cm. At tire inflation pressure of 1.0 bar the drawbar pull values were 20, 25 and 35 kg for drawbar heights of 30, 35 and 40 cm. By the increase in tracted weight from 25 to 75 kg the drawbar pull increased from 15 to 50, 17.5 to 45 and 20 to 40 Kg at tire inflation pressures of 2, 1.5, 1.0 bar respectively. From these results it was indicated that, increasing the drawbar height leads to increasing the drawbar pull and with increasing the tracted weights the drawbar pull increased also at reduction ratio of 1:4.5.

101

(TIP 2.0 bar)

60 kg 25

kg 50

kg 75

Drawbar pull (Kgf)

50 40 30 20 10 0 30 60

35

40

(TIP 1.5 bar)

Drawbar pull (Kgf)

50 40 30 20 10 0 30 70

35

40

(TIP 1.0 bar)

Drawbar pull (Kgf)

60 50 40 30 20 10 0 30

35 Drawbar height (Kg)

40


102

Fig. (4.22) and table (7.6) in appendix shows that the effect of drawbar height on drawbar pull at three added weights, three tire inflation pressures and reduction ratio of (1:3.5). Drawbar pull values were 15, 20 and 27.5 kg for drawbar heights of 30, 35 and 40 cm, respectively at traction weight of 25 kg. These results were obtained using tire inflation pressure of 2 bar. The results showed the same trend at traction weights of 50 and 75 kg with reduction ratio of (1:3.5). At tire inflation pressure of 1.5 bar the drawbar pull values were 15.5, 20 and 30 kg for drawbar heights of 30, 35 and 40 cm. At tire inflation pressures of 1.0 bar the drawbar pull values were 17.5, 25 and 32.5 kg for drawbar heights of 30, 35 and 40 cm. By the increase in tracted weight from 25 to 75 kg the drawbar pull increased from 15 to 37.5, 15.5 to 42.5 and 17.5 to 47.5 Kg at tire inflation pressures of 2, 1.5, 1.0 bar respectively. From these results it was indicated that, increasing the drawbar height leads to increasing the drawbar pull and with increasing the tracted weights the drawbar pull increased also at reduction ratio of 1:3.5.

103

(TIP 2.0 bar) 50 kg 25

Drawbar pull (Kgf)

45

kg 50

kg 75

40 35 30 25 20 15 10 5 0 30

50

35

40

(TIP 1.5 bar)

45

Drawbar pull (Kgf)

40 35 30 25 20 15 10 5 0 30 50

35

40

(TIP 1.0 bar)

45

Drawbar pull (Kgf)

40 35 30 25 20 15 10 5 0 30

35 Drawbarheight (cm)

40


104

Fig. (4.23) and table (7.6) in appendix shows that the effect of drawbar height on drawbar pull at three added weights, three tire inflation pressures and reduction ratio of (1:2.5). It can be seen that drawbar pull increased with increasing the drawbar height, this increase is attributed to the weight transferred due to the increase of drawbar height. Drawbar pull values were 15, 15 and 25 kg for drawbar heights of 30, 35 and 40 cm, respectively at traction weight of 25 kg. These results were obtained using tire inflation pressure of 2 bar. The results showed the same trend at traction weights of 50 and 75 kg with reduction ratio of (1:2.5). At tire inflation pressure of 1.5 bar the drawbar pull values were 15, 17.5 and 27.5 kg for drawbar heights of 30, 35 and 40 cm. At tire inflation pressure of 1.0 bar the drawbar pull values were 15, 20 and 30 kg for drawbar heights of 30, 35 and 40 cm height at the same conditions. By the increase in tracted weight from 25 to 75 kg the drawbar pull increased from 15 to 35, 15 to 40 and 15 to 45 kg at tire inflation pressures of 2, 1.5, 1.0 bar respectively. From these results it was indicated that, increasing the drawbar height leads to increasing the drawbar pull and with increasing the tracted weights the drawbar pull increased also at reduction ratio of 1:2.5.

105

(TIP 2.0 bar)

50 45

kg 25

kg 50

kg 75

Drawbar pull (Kgf)

40 35 30 25 20 15 10 5 0 30

60

35

40

(TIP 1.5 bar)

Drawbar pull (Kgf)

50 40 30 20 10 0 30

60

35

40

(TIP 1.0 bar)

Drawbar pull (Kgf)

50 40 30 20 10 0 30


40


106

Fig. (4.24) and table (7.6) shows the effect of tire inflation pressures on drawbar pull at three drawbar heights ,three reduction ratios and three traction weights of (25, 50 and 75 kg). At traction weights of 25 kg as shown on fig. (4.24 A) the figure indicated that the increase in tire inflation pressure decreased the drawbar pull to 20, 17.5 and 15 kg for tire inflation pressures of 1.0, 1.5 and 2.0 bar, respectively at 30 cm drawbar height with the ground. These results were obtained by using reduction ratio of (1:4.5). The results showed the same trend at 35 and 40 cm drawbar height. Drawbar pull were 17.5, 15.5 and 32.5 kg for tire inflation pressures of 1.0, 1.5 and 2.0 bar at reduction ratio of (1:3.5). And the drawbar pull were 15, 15 and 15 kg for tire inflation pressures of 1.0, 1.5 and 2.0 bar at reduction ratio of (1:2.5) at the same conditions. On the other hand increasing the drawbar height from 30 to 40 cm increased the drawbar pull from 20 to 35, 17.5 to 32.5 and 15 to 30 kg at reduction ratios of 1:4.5, 1:3.5 and 1:2.5 respectively at tire inflation pressure of 1.0 bar. At traction weight 50 kg as shown in fig. (4.24 B) drawbar pull were 35, 32.5 and 30 kg for tire inflation pressures of 1.0, 1.5 and 2.0 bar, respectively with 30 cm drawbar height. These results were obtained using the reduction ratio of (1:4.5). The result showed the same trend at 35 and 40 cm drawbar height. Drawbar pull were 35, 30 and 30 kg for tire inflation pressures of 1.0, 1.5 and 2.0 bar at reduction ratio of (1:3.5) and the drawbar pull were 30, 27.5

107

and 25 kg for tire inflation pressures of 1.0, 1.5 and 2.0 bar at reduction ratio of (1:2.5) with the same conditions. On the other hand increasing the drawbar height from 30 to 40 cm increased the average drawbar pull from 35 to 45, 35 to 42.5 and 30 to 40 kg at reduction ratios of 1:4.5, 1:3.5 and 1:2.5 respectively at tire inflation pressure of 1.0 bar. At traction weight of 75 kg as shown on fig. (4.24 C) Drawbar pull values were 50, 45 and 40 kg for tire inflation pressures of 1.0, 1.5 and 2.0 bar, respectively with 30 cm drawbar height. These results were obtained by using the reduction ratio of (1:4.5). The results showed the same trend at 35 and 40 cm drawbar height. Drawbar pull were 47.5, 42.5 and 37.5 kg for tire inflation pressures of 1.0, 1.5 and 2.0 bar at reduction ratio of (1:3.5) and the drawbar pull were 45, 40 and 35 kg for tire inflation pressures of 1.0, 1.5 and 2.0 bar at reduction ratio of (1:2.5) with the same conditions. On the other hand increasing the drawbar height from 30 to 40 cm increased the drawbar pull from 50 to 60, 47.5 to 55 and 45 to 52.5 kg at reduction ratios of 1:4.5, 1:3.5 and 1:2.5 respectively at tire inflation pressure of 1.0 bar. From these results it was found that increasing the drawbar height increased the weight transferred to the rear axle and result in higher rear axle reaction and this increased the drawbar pull which led to larger contact surface with the ground, while increasing the weight transferred.

108

(RR 1:4.5)

(RR 1:4.5)

(RR 1:4.5)

70

40

30 cm

35 cm

Drawbar pull (Kgf)

35 30 25 20 15 10 5 0 1

35

1.5

2

Drawbar pull (Kgf)

35 cm

30 cm

40 cm

35 cm

40 cm

60 50 40 30 20 10 0

1

45

(RR 1:3.5)

1.5

2

1

60

(RR 1:3.5)

1.5

2

(RR 1:3.5)

40

30

50

35

25

30

20

25

15

20

40 30

15

10

20

10

5

10

5

0

0

1 35

1.5

2

0

1

45

(RR 1:2.5)

1.5

2

1

60

(RR 1:2.5)

40

30 Drawbar pull (Kgf)

30 cm

50 45 40 35 30 25 20 15 10 5 0

40 cm

1.5

2

(RR 1:2.5)

50

35

25

40

30

20

25

15

20

30 20

15

10

10

5

5

0

0

1

1.5 TIP (bar)

2

(A)

10 0

1

1.5 TIP (bar)

(B)

2

1

1.5

2

TIP (bar)

(C)

Fig. (4.24) Effect of tire inflation pressures (TIP) on drawbar pull at three drawbar heights and three reduction ratios (RR) at three traction weights (A) 25 kg, (B) 50 kg and (C) 75 kg.

109

4-1-2-4- Optimum operational conditions at unpaved road. The maximum forward speed of the power unit prone cart was 3.76 km/h, obtained at reduction ratio of (1:2.5), tire inflation pressure of 2 bar, traction weight of 25 kg and drawbar height of 30 cm. At this condition the slippage value of recorded 7.41 %, and the value of drawbar pull was 15 kg. On the other hand the best value as minimum slippage of the power unit prone cart was 1.12 %, obtained at reduction ratio of (1:4.5), tire inflation pressure of 1.0 bar, traction weight of 25 kg and drawbar height of 40 cm. While the forward speed was 0.87 km/h and drawbar pull was 35 kg were recorded at this condition. When the maximum drawbar pull of the power unit prone cart was 60 kg, obtained at reduction ratio of (1:4.5), tire inflation pressure of 1.0 bar, traction weight of 75 kg and drawbar height of 40 cm. While the forward speed was 0.69 km/h as minimum value and slippage was 3.1 % were recorded at this condition.

110

5- SUMMARY AND CONCLUSION The main results gained from the present study may be summarized as follows: 1- Evaluation of the human power unit at paved road: a) Forward speed: *

The maximum Forward speed reached at a reduction ratio, 1:4.5, tire

inflation pressures of, (1.0, 1.5 and 2.0 bar), traction weight of 75 kg and drawbar height of 30cm, were 1.39, 1.41 and 1.47 km/hr respectively. *


inflation pressures, (1.0, 1.5 and 2.0 bar), traction weight of 75 kg and drawbar height of 30cm, were 1.43, 2.34 and 2.57 km/hr respectively. *


inflation pressures of, (1.0, 1.5 and 2.0 bar), traction weight of 75 kg and drawbar height of 30cm, were 1.44, 3.30 and 3.70 km/hr respectively. b) Slippage: *

The minimum value of slippage reached at a reduction ratio, 1:4.5, tire

inflation pressures of, (1.0, 1.5 and 2.0 bar, traction weight of 75 kg and drawbar height of 40cm, were 0.33, 0.60247 and 0.96 %) respectively.

*

The minimum value of slippage was reached at a reduction ratio of, 1:3.5,

tire inflation pressures of, (1.0, 1.5 and 2.0 bar) were 1.14, 1.29 and 1.62 % respectively, with traction weight of 75 kg and drawbar height of 40cm. *


tire inflation pressure, (1.0, 1.5 and 2.0 bar) were 1.98, 2.296 and 2.46 % respectively, at traction weight of 75 kg and drawbar height of 40cm. c) Drawbar pull: *

The maximum value of drawbar pull was reached at a reduction ratio of,

1:4.5, tire inflation pressure, (1.0, 1.5 and 2.0 bar) were 80, 70 and 65 kg respectively, at traction weight of 125 kg and drawbar height of 40cm. *


1:3.5, tire inflation pressure, (1.0, 1.5 and 2.0 bar) were 75, 65.5 and 62.5 kg respectively, at traction weight of 125 kg and drawbar height of 40cm. *


1:2.5, tire inflation pressure, (1.0, 1.5 and 2.0 bar) were 70, 62.5 and 60 kg respectively, at traction weight of 125 kg and drawbar height of 40cm. The optimum operational condition at paved road: The maximum forward speed of the power unit prone cart was 3.7 km/hr, obtained at reduction ratio of (1:2.5), tire inflation pressure of 2 bar, traction weight 75 kg and drawbar height 30 cm. At this condition the value of slippage recorded 3.05%, and the value of drawbar pull was 30 kg.

112

On the other hand the best value as minimum slippage of the power unit prone cart was 0.33 %, obtained at reduction ratio of (1:4.5), tire inflation pressure of 1.0 bar, traction weight 75 kg and drawbar height 40 cm. While the forward speed was 1.3 km/hr and drawbar pull was 55 kg were recorded at this condition. When the maximum drawbar pull of the power unit prone cart was 80 kg, obtained at reduction ratio of (1:4.5), tire inflation pressure of 1.0 bar, traction weight 125 kg and drawbar height 40 cm. While the forward speed was 1.12 km/hr as minimum value and slippage was 0.64% were recorded at this condition. 2- Evaluation of the human power unit at unpaved road: *

The maximum Forward speed was reached at a reduction ratio of, 1:4.5,

tire inflation pressures of, (1.0, 1.5 and 2.0 bar) were 0.99, 1.01 and 1.14 km/hr respectively, at traction weight of 25 kg and drawbar height of 30cm. *


tire inflation pressures of, (1.0, 1.5 and 2.0 bar) were 1.97, 2.107 and 2.43 km/hr respectively, at traction weight of 25 kg and drawbar height of 30cm. *


tire inflation pressures of, (1.0, 1.5 and 2.0 bar) were 2.93, 3.20 and 3.76 km/hr respectively, at traction weight of 25 kg and drawbar height of 30cm.

113

b) Slippage: *


tire inflation pressures of, (1.0, 1.5 and 2.0 bar) were 1.12, 1.98 and 2.11 % respectively, at traction weight of 25 kg and drawbar height of 40cm. *


tire inflation pressures of, (1.0, 1.5 and 2.0 bar) were 2.44, 2.67 and 3.57 % respectively, at traction weight of 25 kg and drawbar height of 40cm. *


tire inflation pressures of, (1.0, 1.5 and 2.0 bar) were 3.76, 3.35 and 5.03 % respectively, at traction weight of 25 kg and drawbar height of 40cm. c) Drawbar pull: *


1:4.5, tire inflation pressures of, (1.0, 1.5 and 2.0 bar) were 60, 55 and 50 kg respectively, at traction weight of 75 kg and drawbar height of 40cm. *

The maximum value of drawbar pull reached at a reduction ratio of, 1:3.5,

tire inflation pressures of, (1.0, 1.5 and 2.0 bar) were 55, 52.5 and 50 kg respectively, at traction weight of 75 kg and drawbar height of 40cm. *


1:2.5, tire inflation pressures of, (1.0, 1.5 and 2.0 bar) , were 52.5, 50 and 45 kg respectively, at traction weight of 75 kg and drawbar height of 40cm. The optimum operational condition at unpaved road:

114

The maximum forward speed of the power unit was 3.76 km/hr, obtained at reduction ratio of (1:2.5), tire inflation pressure of 2 bar, traction weight of 25 kg and drawbar height 30 cm. At this condition the value of slippage recorded 7.41 %, and the value of drawbar pull was 15 kg. On the other hand the best value as minimum slippage of the power unit prone cart was 1.12 %, obtained at reduction ratio of (1:4.5), tire inflation pressure of 1.0 bar, traction weight 25 kg and drawbar height 40 cm. While the forward speed was 0.87 km/hr and drawbar pull was 35 kg were recorded at this condition. When the maximum drawbar pull of the prone cart was 60 kg, obtained at reduction ratio of (1:4.5), tire inflation pressure of 1.0 bar, traction weight 75 kg and drawbar height 40 cm. While the forward speed was 0.69 km/hr as minimum value and slippage was 3.11 % were recorded at this condition.

* Recommendation:

115

1- The proposed human power unit can be manufactured with local material at local workshops. 2- Using the human power unit to provide job opportunities for youth. 3- The unit must be used under optimum operation condition at paved road to maximum drawbar pull of the power unit of 80 kg, at reduction ratio of (1:4.5), tire inflation pressure of 1.0 bar, traction weight 125 kg and drawbar height 40 cm with forward speed was 1.12 km/hr. 4- The unit must be used under optimum operation condition at unpaved road to maximum drawbar pull of the power unit of 60 kg, at reduction ratio of (1:4.5), tire inflation pressure of 1.0 bar, traction weight 75 kg and drawbar height 40 cm with forward speed was 0.69 km/hr.

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Taylor .J.H and E.C Burt (1975). Track and tire performance in agricultural soil. Taylor, H. James (1976). comparative traction performance of R - 1, R - 3 and R -4 tractor tires TRANSACTION of the A.S.A.E. 19(1).14-16. Taylor, James H., Eddie C. Burt, Alvin. C. Bailey (1976). Radial tire performance in firm and soft soils .TRANSACTION of the ASAE 19(6)1005-1007. Taylor , J . H.:A.C. Trouse ;E.C.Burt and A.C.Bailley ,(1982). Multi – passes behavior of pneumatic tire in tilled soil . TRANSACTION of ASAE , 25 ; pp.1229 – 1231 , 1236. Ting LH., Raasch CC., Brown DA., et al. (1998). Sensor motor state of the contralateral leg affects psilateral muscle coordination of pedaling. J.Neurophysiol., 1998, 80, p. 1341-1351. Ting LH., Kautz SA., Brown DA., et al. (1999). Phase reversal of biomechanical functions and muscle activity in backward pedaling. J. Neurophysiol., 1999, 81, p. 544-551. Ting LH., Kautz SA., Brown DA., et al.(2000). Contra lateral movement and extensor force generation alter flexion phase muscle coordination in pedalling. J. Neurophysiol., 2000, 83, p. 3351-3365. Willey J., R. Walker. F. Edition and Halliday K. (1997). "Fundamentals of physics" sons. Wilson, D. G. (2004). Bicycling Science, Third Edition. The MIT Press, Cambridge, Massachusetts.

126

Wolkolski, R. P. (1990). "Relationship between wheel-traffic induced soil compaction, nutrient, availability, and crop growth: a review." Journal of Production Agriculture, 3(4), 460-469. Zombori, J. (1967).Drawbar pull tests of various traction devices on sandy soils .J. Cited by Burt and Baily (1982). Zombori ,J.(1997).Drawbar pull tests of various traction devices on sandy soils .J. Terramech . 4(1) : 9 – 17. ‫المراجع العربية‬ –

‫ دار المعاار‬- ‫) الميكنا والجاراراا الاراةيا كليا الاراةا –جامعا الاااةر‬6791 ‫جورج باسيلى حناا‬ ‫جمهوري مصر العربي‬

127

Table (7.1): Effect of drawbar height on forward speed at three adding weights and three different tire inflation pressures and three reduction ratio on paved road. Traction weight 75 kg Reduction ratio

1: 4.5

1: 3.5

1: 2.5

Tire inflation pressures (bar)

Traction weight 100 kg


Drawbar height cm 30

35

40

30

35

40

30

35

40

1

1.39

1.341

1.3

1.35

1.295

1.195

1.25

1.17

1.12

1.5

1.41

1.35

1.33

1.38

1.31

1.26

1.23

1.19

1.15

2

1.47

1.45

1.43

1.39

1.38

1.36

1.27

1.26

1.2

1

1.425

1.3805

1.36

1.39

1.3475

1.2925

1.295

1.24

1.155

1.5

2.335

2.105

1.875

1.91

1.675

1.62

1.58

1.56

1.52

2

2.565

2.305

2.1

2.125

1.85

1.69

1.695

1.625

1.585

1

1.44

1.41

1.4

1.41

1.36

1.35

1.3

1.27

1.23

1.5

3.3

2.9

2.51

2.4

2

1.94

1.89

1.89

1.87

2

3.7

3.2

2.81

2.9

2.3

1.98

2.1

1.97

1.93

Table (7.2): Effect of drawbar height on slippage at three adding weights and three different tire inflation pressures and three reduction ratio on paved road. Traction weight 75 kg Reduction ratio

Tire inflation pressures (bar) 1

1: 4.5 1.5 2 1 1: 3.5 1.5 2 1 1: 2.5 1.5 2




35

40

30

35

40

30

0.81235 0.65988 0.33333 0.93333 0.79661 0.41667 1.62037 0.96482 0.83333 0.60247 1.22105 1.02222 0.83333

1.7037

35

40

1.2

0.64444

1.34753 1.04321

2.08597 1.09568 0.95926 2.27099 1.52593 1.30059 2.71173 2.15556 1.77778 1.90132 1.29972 1.13774 2.21851 1.68954 1.13593 3.14265 2.39928 1.62694 1.93151 1.54491 1.28776 2.50071 1.86652 1.77208 3.36773 2.68428 2.52212 2.54557

1.7563

1.62124 3.03916 2.18859 1.96294 3.63713

2.6264

2.39939

2.9703

1.97956 1.92214 3.48368 2.54248 1.81518 4.62492 3.55855 2.64943

2.93821 2.29648 2.01305 3.74037 2.67082 2.67082 4.99175 3.98102 3.98102 3.04517 2.45691 2.32322 3.84733 2.83126 2.58529 4.54254 3.07725 2.98099

Table (7.3): Effect of drawbar height on drawbar pull at three adding weights and three different tire inflation pressures and reduction ratio on paved road. Traction weight 75 kg Reduction ratio


1: 4.5

1.5 2 1

1: 3.5

1.5 2 1

1: 2.5

1.5 2




35

40

30

35

40

30

35

40

42.5

50

55

45

55

70

65

70

80

40

45

50

45

50

60

55

60

70

35

40

45

40

45

55

50

55

65

40

45.25

55.5

42.5

52.25

65

60

65.5

75

35.5

42.25

45.25

40

47.55

57.5

52.5

57.5

65.5

32.5

37.5

42.5

37.5

42.5

52.5

50

55

62.5

35

42.5

52.5

37.5

47.5

60

57.5

62.5

70

32.5

37.5

42.5

35

45

57.5

52.5

57.5

62.5

30

35

40

35

40

50

50

55

60

Table (7.4): Effect of drawbar height on forward speed at three adding weights and three different tire inflation pressures and three reduction ratio on unpaved road. Traction weight 25 kg Reduction ratio


1: 4.5

1.5 2 1

1: 3.5

1.5 2 1

1: 2.5

1.5 2




35

40

30

35

40

30

35

40

0.99

0.94

0.87

0.86

0.84

0.81

0.81

0.75

0.69

1.01

0.99

0.9

0.9

0.85

0.81

0.84

0.8

0.75

1.14

1.04

0.99

0.93

0.84

0.83

0.89

0.8

0.78

1.97

1.657

1.472

1.589

1.435

1.36

1.414

1.299

1.265

2.107

1.915

1.795

1.89

1.679

1.577

1.689

1.349

1.317

2.43

2.33

2.144

2.017

1.869

1.625

1.844

1.499

1.379

2.93

2.37

2.02

2.32

2.01

1.89

2.02

1.85

1.82

3.2

2.82

2.67

2.86

2.51

2.34

2.54

2.3

1.88

3.76

3.6

3.3

3.1

2.9

2.4

2.8

2.2

1.98

Table (7.5): Effect of drawbar height on slippage at three adding weights and three different tire inflation pressures and three reduction ratio on unpaved road. Traction weight 25 kg Reduction ratio


1: 4.5

1.5 2 1

1: 3.5

1.5 2 1

1: 2.5

1.5 2




35

2.11201

1.66778

3.02913

40

30

35

40

30

35

1.12324 2.64222

2.49892

2.33819

3.65964 3.27274 3.10078

2.11201

1.98338 3.27274

2.55624

2.49892

4.90635 3.70263 3.27274

3.61665

3.12944

2.11201 4.04655

3.70263

2.47026

5.62285 4.84903 3.87459

3.92158

2.93222

2.44339 4.66531

4.09693

3.41502

5.79674 4.89892 4.25509

4.32652

3.80093

2.67081 5.63007

4.17602

3.58079

6.4811

5.51403

4.26942

3.57302 6.30592

5.69552

4.68658

7.76438 6.70916 5.48859

5.72716

4.19265

3.75953 6.69241

5.68694

4.49584

7.92583 6.51709 5.40541

5.61991

5.48584

3.35425 7.97941

5.78781

4.65466

8.05985 6.15616 5.00116

7.40741

5.40541

5.03003 8.56928

7.69241

6.90691

9.90991 8.56928

4.9334

40

4.13495

7.0946

Table (7.6): Effect of drawbar height on drawbar pull at three adding weights and three different tire inflation pressures and reduction ratio on unpaved road. Traction weight 25 kg Reduction ratio


1: 4.5

1.5 2 1

1: 3.5

1.5 2 1

1: 2.5

1.5 2




35

40

30

35

40

30

35

40

20

25

35

35

40

45

50

55

60

17.5

22.5

32.5

32.5

37.5

42.5

45

50

55

15

20

30

30

35

40

40

45

50

17.5

25

32.5

35

37.5

42.5

37.5

52.5

55

15.5

20

30

30

35

40

42.5

47.5

52.5

15

20

27.5

30

35

37.5

47.5

45

50

15

20

30

30

35

40

35

50

52.5

15

17.5

27.5

27.5

32.5

37.5

40

45

50

15

15

25

25

30

35

45

40

45

ANOVA tables keys: S. V

: Source of variance.

D. F

: Degree of freedom.

S. S

: Squares of Standard deviations.

M. S

: Mean of Standard deviations squares.

F cal

: F value calculated from data.

Fsh 5 %

: F value from Stedecor Tables at 5 % significant.

Fsh 1 %

: F value from Stedecor Tables at 1 % .

A

: Reduction ratio.

B

: Tire inflation pressure.

C

: Drawbar height.

D

: Traction weight.

AB

: Interaction between A and B.

AC

: Interaction between A and C.

AD

: Interaction between A and BD.

BC

: Interaction between B and C.

BD

: Interaction between B and D.

CD

: Interaction between C and D.

ABCD

: Interaction between A, B, C and D.

Table (7.7): ANOVA for Forward speed on paved road. S .V

dF

SS

M S

F calc

F sh 5%

F sh 1%

Treat Blocks A B C D AB AC AD BC BD CD ABCD Error Total

80

66.0265

0.8253

281.34**

1.56

1.37

2

0.0058

0.0029

0.99

5.3

4.61

2

26.2659

13.1330

4476.73**

5.3

4.61

2

10.2634

5.1317

1749.28**

5.3

4.61

2

1.7168

0.8584

292.61**

5.3

4.61

2

6.3432

3.1716

1081.13**

5.3

4.61

4

11.7270

2.9318

999.37**

3.72

3.32

4

0.6620

0.1655

56.41**

3.72

3.32

4

3.7603

0.9401

320.45**

3.72

3.32

4

0.2168

0.0542

18.47**

3.72

3.32

4

0.9498

0.2374

80.94**

3.72

3.32

4

0.2146

0.0537

18.29**

3.72

3.32

16

3.9067

0.2442

83.23**

2.19

2.04

160

0.4694

0.0029

242

66.5017

0.2748

Table (7.8): ANOVA for Slippage on paved road. S .V

dF

SS

M S

F calc

F sh 5%

F sh 1%


80

275.6912

3.4461

1230.37**

1.56

1.37

2

0.2174

0.1087

38.82**

5.3

4.61

2

170.3344

85.1672

30407.17**

5.3

4.61

2

18.2905

9.1452

3265.11**

5.3

4.61

2

30.0520

15.0260

5364.71**

5.3

4.61

2

31.2453

15.6226

5577.73**

5.3

4.61

4

7.0044

1.7511

625.19**

3.72

3.32

4

4.9026

1.2257

437.59**

3.72

3.32

4

5.6927

1.4232

508.12**

3.72

3.32

4

0.5804

0.1451

51.80**

3.72

3.32

4

0.9026

0.2257

80.57**

3.72

3.32

4

1.1321

0.2830

101.05**

3.72

3.32

16

5.5543

0.3471

123.94**

2.19

2.04

160

0.4481

0.0028

242

276.3568

1.1420

Table (7.9): ANOVA for Drawbar pull on paved road. S .V

dF

SS

M S

F calc

F sh 5%

F sh 1%


80

30975.0000

387.1875

46.21**

1.56

1.37

2

96.9136

48.4568

5.78**

5.3

4.61

2

1338.8889

669.4444

79.90**

5.3

4.61

2

3105.5556

1552.7778

185.33**

5.3

4.61

2

8734.7222

4367.3611

521.25**

5.3

4.61

2

16238.8889

8119.4444

969.06**

5.3

4.61

4

151.3889

37.8472

4.52**

3.72

3.32

4

5.5556

1.3889

0.17

3.72

3.32

4

55.5556

13.8889

1.66

3.72

3.32

4

222.2222

55.5556

6.63**

3.72

3.32

4

155.5556

38.8889

4.64**

3.72

3.32

4

605.5556

151.3889

18.07**

3.72

3.32

16

361.1111

22.5694

2.69**

2.19

2.04

160

1340.5864

8.3787

242

32412.5000

133.9360

Table (7.10): ANOVA for Forward speed on unpaved road. S .V

dF

SS

M S

F calc

F sh 5%

F sh 1%


80

137.2491

1.7156

3477.38**

1.56

1.37

2

0.0201

0.0100

20.33**

5.3

4.61

2

112.1931

56.0966

113702.16**

5.3

4.61

2

3.8732

1.9366

3925.33**

5.3

4.61

2

2.8090

1.4045

2846.76**

5.3

4.61

2

7.2244

3.6122

7321.56**

5.3

4.61

4

3.9997

0.9999

2026.74**

3.72

3.32

4

1.9805

0.4951

1003.59**

3.72

3.32

4

3.0432

0.7608

1542.04**

3.72

3.32

4

0.0259

0.0065

13.13**

3.72

3.32

4

0.4623

0.1156

234.26**

3.72

3.32

4

0.0012

0.0003

0.61

3.72

3.32

16

1.6365

0.1023

207.32**

2.19

2.04

160

0.0789

0.0005

242

137.3481

0.5676

Table (7.11): ANOVA for Slippage on unpaved road. S .V

dF

SS

M S

F calc

F sh 5%

F sh 1%


80

926.4833

11.5810

36759.22**

1.56

1.37

2

0.0011

0.0006

1.81

5.3

4.61

2

546.8255

273.4127

867835.57**

5.3

4.61

2

87.9455

43.9728

139573.30**

5.3

4.61

2

115.9375

57.9687

183997.72**

5.3

4.61

2

114.1725

57.0863

181196.67**

5.3

4.61

4

7.4406

1.8602

5904.30**

3.72

3.32

4

13.2746

3.3186

10533.65**

3.72

3.32

4

8.4812

2.1203

6729.99**

3.72

3.32

4

2.6334

0.6584

2089.68**

3.72

3.32

4

6.0311

1.5078

4785.84**

3.72

3.32

4

2.9023

0.7256

2303.03**

3.72

3.32

16

20.8391

1.3024

4134.06**

2.19

2.04

160

0.0504

0.0003

242

926.5348

3.8287

Table (7.12): ANOVA for Drawbar pull on unpaved road. S .V

dF

SS

M S

F calc

F sh 5%

F sh 1%


80

34325.4630

429.0683

68.06**

1.56

1.37

2

3.8580

1.9290

0.31**

5.3

4.61

2

939.3519

469.6759

74.50**

5.3

4.61

2

1653.2407

826.6204

131.13**

5.3

4.61

2

5224.0741

2612.0370

414.35**

5.3

4.61

2

25892.1296

12946.0648

2053.62**

5.3

4.61

4

7.8704

1.9676

0.31

3.72

3.32

4

12.0370

3.0093

0.48

3.72

3.32

4

14.8148

3.7037

0.59

3.72

3.32

4

6.4815

1.6204

0.26**

3.72

3.32

4

205.0926

51.2731

8.13**

3.72

3.32

4

259.2593

64.8148

10.28**

3.72

3.32

16

111.1111

6.9444

1.10

2.19

2.04

160

1008.6420

6.3040

242

35337.9630

146.0246

‫‪ -4‬لىادت ي(ب من خ لل عند م‬ ‫قىت وذل عند نسةث خ في‬

‫ل ظروف ي لطريق لوير ملهد عند مع‬

‫قىت شد لآللبث ‪ 61‬ك(بو‬

‫‪ )5.4.5‬و ضو ع(ل خ بل ر ب) ج ‪ 5.1‬بب) و مالب)ا م ب) ث ‪55‬‬

‫ك(و و خف)ج ر ‪ 41‬سو و ذل عند سرعث خقدميث ‪ 1.6.‬كو‪ /‬س)عث‪.‬‬

‫‪5‬‬

‫‪ -2‬حقل نسبة انلزالق لآلللة عنلد نسلبة تخفلٌض ي‪ 1:3.5‬وضلغوط الواء داخلل الوجلل ي‪2.0 ،1.5,1.0‬‬ ‫بار علً التوالً وح مال مضا ة ‪ 25‬كجآل و ارتفاع جر ‪ 40‬سآل كان ي‪،2.62302 ،2.44331‬‬ ‫‪. % 3.52302‬‬ ‫‪ -3‬حقل نسبة انلزالق لآلللة عنلد نسلبة تخفلٌض ي‪ 1:2.5‬وضلغوط الواء داخلل الوجلل ي‪2.0 ،1.5,1.0‬‬ ‫بار على التوالً وح مال مضا ة ‪ 25‬كجآل وارتفاع جر ‪ 40‬سلآل كانل ي‪،3.35425 ،3.25153‬‬ ‫‪. % 5.03003‬‬

‫ج‪ -‬قوة الشد‪:‬‬ ‫‪ -1‬حعلى قوة شد لآللة عند نسبة تخفٌض ي‪ 1:4.5‬وضلغوط الواء داخلل الوجلل ي‪ 2.0 ،1.5,1.0‬بلار‬ ‫على التوالً وح مال مضا ة ‪ 25‬كجآل وارتفاع جر ‪ 40‬سآل كان ي‪ 50 ،55، 60‬كجآل ‪.‬‬ ‫‪ -2‬حعلى قوة شد لآللة عند نسبة تخفٌض ي‪ 1:3.5‬وضلغوط الواء داخلل الوجلل ي‪ 2.0 ،1.5,1.0‬بلار‬ ‫على التوالً وح مال مضا ة ‪ 25‬كجآل وارتفاع جر ‪ 40‬سآل كان ي‪ 50 ،52.5، 55‬كجآل ‪.‬‬ ‫‪ -3‬حعلى قوة شد لآللة عند نسبة تخفٌض ي‪ 1:2.5‬وضغوط اواء داخلل الوجلل ي‪ 2.0 ،1.5,1.0‬بلار‬ ‫على التوالً وح مال مضا ة ‪ 25‬كجآل وارتفاع جر ‪ 40‬سآل كان ي‪ 35 ،50، 52.5‬كجآل ‪.‬‬

‫*التوصيات‪:‬‬ ‫‪ -5‬يلكن خصنيع وادت لقد ت ي لى ش لصويرت ب)سد د م )م)ج مح يث‪.‬‬ ‫‪ -2‬سد د م وادت لقد ت لدى ير رص علل م‬ ‫‪ -3‬لىادت ي(ب من خ لل عند م‬ ‫وذلب عنبد نسبةث خ فبي‬

‫ل ل شة)ب‪.‬‬

‫ل ظروف ي لطريق لللهد عند مع‬

‫قىت شد لآللبث ‪ 01‬ك(بو قبىت‬

‫‪ )5.4.5‬و ضبو ع(بل خ بل ر ب) ج ‪ 5.1‬بب) و مالب)ا م ب) ث ‪525‬‬

‫ك(و و خف)ج ر ‪ 41‬سو و ذل عند سرعث خقدميث ‪ 5.52‬كو‪ /‬س)عث‪.‬‬

‫‪6‬‬

‫‪-1‬‬

‫حعلى قوة شد لآللة عنلد نسلبة تخفلٌض ي‪ 1:4.5‬وضلغوط الواء داخلل الوجلل ي‪2.0 ،1.5,1.0‬‬ ‫بار على التوالً وح مال مضا ة ‪ 125‬كجآل وارتفاع جر ‪ 40‬سآل كان ي‪ 65 ،20، 80‬كجآل ‪.‬‬

‫‪-2‬‬

‫حعلى قوة شد لآللة عنلد نسلبة تخفلٌض ي‪ 1:3.5‬وضلغوط الواء داخلل الوجلل ي‪2.0 ،1.5,1.0‬‬ ‫بللار علللى التللوالً وح مللال مضللا ة ‪ 125‬كجللآل وارتفللاع جللر ‪ 40‬سللآل كان ل ي‪62.5 ،65.5، 25‬‬ ‫كجآل ‪.‬‬

‫‪-3‬‬

‫حعلى قوة شد لآللة عنلد نسلبة تخفلٌض ي‪ 1:2.5‬وضلغوط الواء داخلل الوجلل ي‪2.0 ،1.5,1.0‬‬ ‫بار على التوالً وح مال مضا ة ‪ 125‬كجآل وارتفاع جر ‪ 40‬سآل كان ي‪ 60 ،62.5، 20‬كجآل ‪.‬‬

‫ثانيا‪ :‬تقييم أداء وحدة القدرة باستخدام الطاقة البشرية في الطريق الغير ممهد‪:‬‬ ‫أ‪ -‬السرعة التقدمية‪:‬‬ ‫‪ -1‬حعلى سرعة تقدمٌة لآللة عند نسبة تخفٌض ي‪ 1:4.5‬وضغوط اواء داخلل الوجلل ي‪2.0 ،1.5,1.0‬‬ ‫بلار علللى التللوالً وح مللال مضللا ة ‪ 25‬كجلآل وارتفللاع جللر ‪ 30‬سللآل كانل ي‪1.14 ،1.01، 0.11‬‬ ‫كآل‪/‬ساعة ‪.‬‬ ‫‪ -2‬حعلى سرعة تقدمٌة لآللة عند نسبة تخفٌض ي‪ 1:3.5‬وضغوط اواء داخلل الوجلل ي‪2.0 ،1.5,1.0‬‬ ‫بار على التوالً وح مال مضلا ة ‪ 25‬كجلآل وارتفلاع جلر ‪ 30‬سلآل كانل ي‪2.43 ،2.102، 1.12‬‬ ‫كآل‪/‬ساعة ‪.‬‬ ‫‪ -3‬حعلى سرعث خقدميث لآللث عنبد نسبةث خ فبي‬ ‫ببب) ) ع ب‬

‫‪ )5.2.5‬وضبوى وبى د خ بل ل (بل ‪2.1 ,5.5,5.1‬‬

‫لدببى لي ومالبب)ا م بب) ث ‪ 25‬ك(ببو و خفبب)ج ببر ‪ 31‬سببو ك)نببح ‪3.56 ,3.21, 2..3‬‬

‫كو‪/‬س)عث)‪.‬‬

‫ب‪ -‬نسبة االنزالق‪:‬‬ ‫‪ -1‬حقل نسبة انلزالق لآلللة عنلد نسلبة تخفلٌض ي‪ 1:4.5‬وضلغوط الواء داخلل الوجلل ي‪2.0 ،1.5,1.0‬‬ ‫بار على التوالً وح مال مضا ة ‪ 25‬كجآل وارتفاع جر ‪ 40‬سلآل كانل ي‪،1.18338 ،1.12324‬‬ ‫‪. % 2.11201‬‬

‫‪5‬‬

‫أوال‪ :‬تقييم أداء وحدة القدرة باستخدام الطاقة البشرية في الطريق الممهد‪:‬‬ ‫أ‪-‬‬

‫السرعة التقدمية‪:‬‬

‫‪ -1‬حعلى سرعة تقدمٌة لآللة عند نسبة تخفٌض ي‪ 1:4.5‬وضغوط اواء داخل الوجلل ي‪2.0 ،1.5,1.0‬‬ ‫بلار علللى التللوالً وح مللال مضللا ة ‪ 25‬كجلآل وارتفللاع جللر ‪ 30‬سللآل كانل ي‪1.42 ،1.41، 1.31‬‬ ‫كآل‪/‬ساعة ‪.‬‬ ‫‪ -2‬حعلى سرعة تقدمٌة لآللة عند نسبة تخفٌض ي‪ 1:3.5‬وضغوط اواء داخل الوجلل ي‪2.0 ،1.5,1.0‬‬ ‫بار على التوالً وح مال مضا ة ‪ 25‬كجآل وارتفاع جر ‪ 30‬سآل كان ي‪2.565 ،2.335، 1.425‬‬ ‫كآل‪/‬ساعة ‪.‬‬ ‫‪ -3‬حعلى سرعث خقدميث لآللث عند نسبةث خ فبي‬

‫‪ )5.2.5‬وضبوى وبى د خ بل ل (بل ‪2.1 ,5.5,5.1‬‬

‫ببب) ) ع بي لدببى لي ومالبب)ا م بب) ث ‪ 55‬ك(ببو و خفبب)ج ببر ‪ 31‬سببو ك)نببح ‪3.51 ,3.31, 5.44‬‬ ‫كو‪/‬س)عث)‪.‬‬

‫ب‪-‬‬

‫نسبة االنزالق‪:‬‬

‫‪ -1‬حقل نسبة انلزالق لآلللة عنلد نسلبة تخفلٌض ي‪ 1:4.5‬وضلغوط الواء داخلل الوجلل ي‪2.0 ،1.5,1.0‬‬ ‫بار على التوالً وح مال مضا ة ‪ 25‬كجآل وارتفاع جر ‪ 40‬سلآل كانل ي‪،0.60242 ،0.33333‬‬ ‫‪. % 0.15126‬‬ ‫‪ -2‬حقل نسبة انلزالق لآلللة عنلد نسلبة تخفلٌض ي‪ 1:3.5‬وضلغوط الواء داخلل الوجلل ي‪2.0 ،1.5,1.0‬‬ ‫بار على التوالً وح مال مضا ة ‪ 25‬كجآل وارتفاع جر ‪ 40‬سلآل كانل ي‪،1.28226 ،1.13224‬‬ ‫‪. % 1.62124‬‬ ‫‪ -3‬حقل نسبة انلزالق لآلللة عنلد نسلبة تخفلٌض ي‪ 1:2.5‬وضلغوط الواء داخلل الوجلل ي‪2.0 ،1.5,1.0‬‬ ‫بار علً التوالً وح مال مضا ة ‪ 25‬كجآل وارتفاع جر ‪ 40‬سلآل كانل ي‪،2.01305 ،1.12214‬‬ ‫‪. % 2.32322‬‬

‫ج‪ -‬قوة الشد‪:‬‬

‫‪4‬‬

‫لت قٌق األاداف السابقة تآل استخداآل و دة قدرة تومل بواسطة الطاقة البشرٌة وكذلك استخداآل و دة‬ ‫ت مٌل خلف ا لة المختبرة وقد حجرٌ التجلارب لً موسلآل ‪ 2002 -2006‬آل بمزرعلة كلٌلة الزراعلة ـل‬ ‫جاموة المنصورة‪.‬‬

‫متغيرات الدراسة‪:‬‬ ‫‪-1‬‬ ‫‪-2‬‬

‫تآل اختبار نوعٌن من الطرق يطرٌق ممهد – طرٌق رٌر ممهد ‪.‬‬ ‫تآل اختبار ثالث نسب تخفٌض ي ‪1:2.5 ،1:3.5 ،1:4.5‬‬

‫‪.‬‬

‫‪-3‬‬

‫تآل اختبار ثالث ضغوط اواء مختلفة للوجل ي‪ 2.0 ،1.5 ،1.0‬بار ‪.‬‬

‫‪-4‬‬

‫تآل اختبار ثالث مستوٌا للجر على ارتفاعا ي‪ 40 ،35 ،30‬سآل من سطح األرض‪.‬‬

‫‪-5‬‬

‫تآل اختبار ثالث ح مال مضا ة ى كل نوع من الطرقي ً الطرٌق الممهد ‪125 ،100، 25‬‬ ‫كجآل ي ً الطرٌق الغٌر ممهد ‪ 25 ،50 ،25‬كجآل ‪.‬‬

‫القياسات واالختبارات المبدئية والحقلية‪:‬‬ ‫تآل تقسٌآل الدراسة إلى مر لتٌن‪:‬‬

‫أوال‪ :‬دراسة مبدئية‪:‬‬ ‫تلآل دراسللة االرتفاعللا المال مللة للجللر وكللذلك الضلغوط المال ملة وكللذلك نسللب التخفللٌض المناسللبة‬ ‫لوروف الومل وح مال المضا ة سب كل نوع من حنواع الطرق‪.‬‬

‫ثانيا‪ :‬قياسات خاصة باالختبارات الحقلية لآللة وشملت ما يلي‪:‬‬ ‫‪-1‬‬

‫السرعة التقدمٌة لآللة‪.‬‬

‫‪-2‬‬

‫نسبة االنزالق‪.‬‬

‫‪-3‬‬

‫قوة الشد لآللة‪.‬‬

‫وتتلخص أهم النتائج المتحصل عليها كما يلي‪:‬‬

‫‪3‬‬

‫و قد اشتملت الدراسة على‪:‬‬ ‫‪ -1‬تجارب مبد ٌة تهدف إلى ت دٌد انسب نسب تخفٌض لآللة و اختٌار االرتفاعا المال مة لنقاط الشلبك‬ ‫وت دٌد األوزان الممكن جرالا بواسلطة الو لدة وكلذلك الضلغوط المال ملة للوجلل‪ .‬باإلضلا ة إللى تجمٌلع‬ ‫البٌانا الالزمة إلتماآل الجزء الثانً من الدراسة‪.‬‬ ‫‪ -2‬تجارب قلٌة تهدف إلى تقٌٌآل حداء ا لة ت‬

‫الوروف ال قلٌة المختلفلة بهلدف دراسلة حكثلر الوواملل‬

‫تأثٌرا على قوى الشد ل تقلٌل نسبة االنزالق مع ت دٌد ح ضل السرعا الناتجة من ا لة‪.‬‬ ‫وقد تآل إجراء التجارب على نوعٌن من األسطح ي طرٌق ممهد – طرٌق رٌلر ممهلد ملع اسلتخداآل ثلالث‬ ‫نسب تخفٌض وثالث مستوٌا من ضغط اإلطارا وثالث مستوٌا للجر وكلذلك ثلالث ح ملال مضلا ة‬ ‫ً كل طرٌق على دة ٌث حن كل نوع من األسلطح تجربلة مسلتقلة وتقٌلٌآل تلأثٌر ذللك عللى قلوى الشلد‬ ‫واالنزالق وسرعة ا لة التقدمٌة‪.‬‬

‫الهدف من الدراسة‪:‬‬ ‫تهدف الدراسة إلى تطوٌر وتصنٌع واختبار وتقٌٌآل و دة قدرة تومل بواسطة الطاقة البشرٌة تناسب‬ ‫مالكً ال ٌازا الصغٌرة من ٌث ال جآل و التكلفة وتلو ر لر‬ ‫ٌها ما ٌلً‪:‬‬ ‫‪-1‬‬

‫حن تكون بسٌطة التصمٌآل وسهلة التشغٌل والصٌانة‪.‬‬

‫‪-2‬‬

‫حن تصنع من الخاما الم لٌة المتا ة لتقلٌل التكالٌف ‪.‬‬

‫‪-3‬‬

‫حن تكون صغٌرة ال جآل ذا كفاءة عالٌة‪.‬‬

‫‪-4‬‬

‫حن تستخدآل األجزاء القٌاسٌة لتو ٌر التكالٌف والوق ‪.‬‬

‫‪-5‬‬

‫حن تكون رخٌصة الثمن لتشجٌع المزارعٌن على اقتنا ها‪.‬‬

‫‪-6‬‬

‫حن تو ر ر‬

‫عمل ح ضل للشباب‪.‬‬

‫‪2‬‬

‫عملل ح ضلل للشلباب عللى حن ٌراعلى‬

‫الملخص العربي‬ ‫تطوير وحدة قدرة باستخدام الطاقة البشرية‬ ‫عاش المصرٌون منذ زمن طوٌل على الشرٌط األخضر بطول النٌلل‪ .‬وبملرور الوصلور حصلب‬ ‫رقوة األرض ال تتسع مع عدد السكان المتنامً مما حدى ذلك إلى ز ف الومران عللى األرض الزراعٌلة‬ ‫الخصلبة‪ .‬وملع تفتل ال ٌلازا الزراعٌللة لً مصلر اضللطر المزارعلون إلللى اسلتخداآل ا ال الزراعٌللة‬ ‫الصغٌرة و التً تتمٌز بانخفاض حثمانها حو اللجوء إلى عملٌا اإلٌجار للمودا‬

‫الزراعٌلة الكبٌلرة ‪ ،‬وقلد‬

‫حدى ذلك إلى زٌادة تكالٌف الوملٌا الزراعٌة ً ال قل‪ ،‬وللذالك كانل ال اجلة إللى تصلمٌآل آللة زراعٌلة‬ ‫تومل بواسطة الشباب تقوآل ببوض األعمال ال قلٌة مثل عملٌلا‬ ‫ا تٌاجا‬

‫ٌلزمها ال قل‪ ،‬مع األخلذ لً اعتبلارا‬

‫لتقدآل مساامة ً تو ٌر لر‬

‫نقلل البلذور والكٌماوٌلا واألسلمدة وحى‬

‫تشلغٌل الذة ا للة حن توملل بواسلطة اثنلٌن ملن الشلباب‬

‫عملل للشلباب وٌمكلن حن تتضلاعف الذة المسلاامة لتوملل بمنووملة عملل‬

‫مكونة من ثالث إلى حربع شباب‪.‬‬ ‫لللذلك توتبللر دراسللة و تطللوٌر و للدة قللدرة باسللتخداآل الطاقللة البشللرٌة ذا حامٌللة خاصللة لمُصللنوً‬ ‫و ُمصللممً ا ال الزراعٌللة بكا للة حنواعهللا‪ ،‬وكللذا الوللاملون للً مج لال الهندسللة الزراعٌللة مللن بللا ثٌن‬ ‫ومدٌري م طا المٌكنة الزراعٌة‪ ،‬وذلك لتووٌآل االستفادة من الذة ا للة وتطلوٌر اسلتخدامها لتوملل لً‬ ‫مجاال حخرى مثل إضا ة و دة عزٌق لها حو إضا ة و دة رش للمبٌدا ‪.‬‬ ‫لللذا للذن اللذا الب للث ٌهللتآل بدراسللة حكثللر الووامللل المل ثرة علللى حداء و للدة الجللر و تقٌللٌآل حدا ل للً‬ ‫األراضللً المختلفللة ي طرٌللق ممهللد حسللفلتً‪ -‬طرٌللق رٌللر ممهللد زراعللً وكللذلك دراسللة قللوى الشللد و‬ ‫االنزالق للوجل و كذلك السرعا التقدمٌة لآللة‪ .‬اذا باإلضا ة إلً دراسة تأثٌر زٌلادة اللوزن عللى ا للة‬ ‫ٌث تآل إجراء اختبارا على قوى الشد و االنزالق و السرعة األمامٌة لآللة‪.‬‬

‫جامعة المنصـورة‬ ‫كلٌة الزراعة‬ ‫قسم الهندسة الزراعٌة‬

‫أعضاء لجنة المناقشة والحكم‬ ‫عنوان الرسالة‪ :‬تطوير وحدة قدرة باستخدام الطاقة البشرية‪.‬‬ ‫إســم البـاحـث‪ :‬وائل محمد فهمً فتح أبو طالب القللً‪.‬‬ ‫لجنة المناقشة والحكم‪:‬‬ ‫االسم‬

‫م‬

‫التوقٌع‬

‫الوظٌفة‬ ‫أستاذ الهندسة الزراعٌة‬

‫‪1‬‬

‫أ‪.‬د ‪ /‬مبارك محمد مصطفى‬

‫‪2‬‬

‫أ‪.‬د‪ /‬ماهر محمد إبراهٌم عبد العال‬

‫‪3‬‬

‫أ‪.‬د ‪ /‬محمد أحمد الشٌخة‬

‫‪4‬‬

‫أ‪.‬د ‪ /‬هشام ناجى عبد المجٌد‬

‫كلٌة الزراعة ‪ -‬جامعة عٌن شمس‬ ‫أستاذ الهندسة الزراعٌة‬ ‫كلٌة الزراعة ‪ -‬جامعة المنصورة‬ ‫أستاذ الهندسة الزراعٌة‬ ‫كلٌة الزراعة ‪ -‬جامعة المنصورة‬ ‫أستاذ الهندسة الزراعٌة و عمٌد الكلٌة‬ ‫كلٌة الزراعة ‪ -‬جامعة المنصورة‬

‫تارٌخ المناقشة‪2118/ 11 / 11 :‬‬ ‫رئٌس القسم‬ ‫أ‪.‬د‪ /‬صالح مصطفى عبد اللطٌف‬

‫وكٌل الكلٌة لشئون الدراسات العلٌا‬ ‫أ‪.‬د‪ /‬السٌد محمود الحدٌدي‬

‫عمٌد الكلٌة‬ ‫أ‪.‬د‪ /‬هشام ناجى عبد المجٌد‬


‫المشرفون ومساعدوهم‬

‫عنوان الرسالة‪ :‬تطوير وحدة قدرة باستخدام الطاقة البشرية‪.‬‬ ‫إســم البــاحـث‪ :‬وائل محمد فهمً فتح أبو طالب القللً‪.‬‬ ‫لجنة اإلشراف‪:‬‬ ‫م‬

‫الوظٌفة‬

‫اإلسم‬

‫التوقٌع‬

‫أستاذ الهندسة الزراعٌة‬

‫‪1‬‬

‫أ‪.‬د ‪ /‬محمد أحمد الشٌخة‬

‫‪2‬‬

‫أ‪.‬د ‪ /‬هشام ناجى عبد المجٌد‬

‫‪3‬‬

‫د ‪ /‬محمد عبد الفتاح مصطفً‬

‫كلٌة الزراعة ‪ -‬جامعة المنصورة‬ ‫أستاذ الهندسة الزراعٌة و عمٌد الكلٌة‬ ‫كلٌة الزراعة ‪ -‬جامعة المنصورة‬ ‫مدرس الهندسة الزراعٌة‬ ‫كلٌة الزراعة ‪ -‬جامعة المنصورة‬

‫تارٌخ المناقشة‪ 2118/ 11 / 11 :‬م‬ ‫رئٌس القسم‬ ‫أ‪.‬د‪ /‬صالح مصطفى عبد اللطٌف‬

‫وكٌل الكلٌة لشئون الدراسات العلٌا‬

‫عمٌد الكلٌة‬

‫أ‪.‬د‪ /‬السٌد محمود الحدٌدي‬

‫أ‪.‬د‪ /‬هشام ناجى عبد المجٌد‬


‫تطوير وحدة قدرة باستخدام الطاقة البشرية‬ ‫رسالة مقدمة من‬

‫وائل محمد فهمي فتح أبو طالب القللي‬ ‫بكالوريوس علوم زراعية‪ -‬كلية الزراعة ‪ -‬جامعة طنطا ‪3002‬م‬ ‫كجزء من متطلبات الحصول على درجة‬ ‫( الماجستير)‬ ‫فى‬ ‫العلوم الزراعٌة‬ ‫(هندسة زراعية )‬ ‫اإلشراف‬ ‫األستاذ الدكتور محـمد أحـمد الشيخــة‬ ‫أستاذ الهندسة الزراعــٌة‬ ‫كلٌة الزراعة ‪ -‬جامعة المنصورة‬

‫األستاذ الدكتور‪/‬هشام ناجى عبد المجيد‬ ‫أستاذ الهندسة الزراعــٌة و عمٌد‬ ‫كلٌة الزراعة ‪ -‬جامعة المنصورة‬

‫الدكتور‪ /‬محمد عبد الفتاح مصطفى‬ ‫مدرس المٌكنة الزراعٌة‬ ‫كلٌة الزراعة ‪ -‬جامعة المنصورة‬

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development of a power unit using the human power

development of a power unit using the human power

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