PERPETUAL CALENDAR

Jan. 25, 1944.

J. Q. STEWART

2,340,153

PERPETUAL CALENDAR

Filed oct. 15, 19211

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INVENToR

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Jay/v o. .srEwA/zr BY

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ATTORNEY

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Jan. 25, 1944.

_1_ Q, STEWART

2,340,153

PERPETUAL CALENDAR Filed Oct. 15, 1941

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ATTORNEY „

Patented Jan. 25, 1944

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2,340,152

UNITED STATES l¿mii-NT 2,340,153Y

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I’ERPE TUAL vCAÍLÈIÑÍDAR

John Q. stewart, Pr'i?cetonl N. J. Application October 15, 1941, .Serial No. ,414,989 3 Claims. (Cl. ‘l0-1079 The present invention relates generally to cal endars and more particularly to improvements in perpetual calendars. The principal object of my invention is to pro

data which ,the .user requires >to 4set kthem .corr-ï

rectly. Mydevice is lparticularly advantageous in .its economy ,of space, .becausetheratio ,i?rarea of .the effective >face .of the îcalendary..pronerfto >the

vide a calender which in itspattern of associa

supplementary >scales is relativelyflarge.

tion >of the days of the week with the days of a month presents the appearance .of an ordinary

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With `the aboveobjects in view, theinvention consists .oj'f `certain novel features, ,as _hereinaft ,rE

simple familiar calendar, whether showing ,a sin

shown anddescribedand then specifically-pointed.

gle month of the current year or a sequence yof

out in the claims.

months; and which, unlike the ordinary calen

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In the .accompanying drawings:

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dars in common use, does not expire at the end of a year or other period but, Without recoursetoV any data not a part o_f the various scales of the

Figures la and lb taken ,together illustrate >the invention .embodied ,in the form fof .a plurality..ofl

apparatus itself, expeditiouslycan he set month after month, year after year, never becoming >ob

Figure _2 illustrates ,the manner lwhich „one of the year-cardsshown in Figure 1b cooperates" with one of the month-'cards shownfinl-Figure '1c

solete.

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year-cards and month cards;

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Another object, implicit; in the accomplishment

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to'produce a familiar ,calendarpattelìm

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of the ñrst, is to provide a perpetual calendar similar in appearance to any ordinary calendar

Figure 3 illustratesV va s_amplemonth .cardof ‘ another embodiment wherein the _current ,mo'iitfhli which readily can be set. for any month Ain vthe 20 is shown with .theneXt preceding y month , and `_the

near or far past `or future, thus vdetermining the day of the week corresponding Vto any date,

next succeeding month;

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Figure 4 shows a sample ,year cardarrangedfto.

whether New Style or `¿Gregorian (our common cooperate withl the vtype of ymonth cards ,shown reckoning), or Old Style or Julian. Although various numerical tables and mechanical devices» 25 inr‘igure Figure 53;illustrates and the manner in lwhich Ka year; already exist for finding the day of the Week cor card such as snownin Figure f1 cooperates with. responding to any date, the `method of operation a month-.card suchas ¿shown inf-:ligure topm-l of my device is of particular ease, Yand since the duce a familiar calendar .pattern kshown-1g, the scales when set have the familiar appearance ofv current or desired .montlnthe previousmonth, an ordinary calendar this device vividly'presents and the following month. y A Y x , Y to unskilled users the whole chronological en vironment of the required date.

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The invention YKwill, be y.clari?ed ifethe relevant> chronological :theory ,is `recalled The succession'

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A further object is to attain the objects already

0fl `days of `the .weekfisin .a y:regular?cycle ofseveny

mentioned by means simple and cheap yet elegant’_ , while .the successioni'of calendardat'es-»inv(living-`~ and compact. That previous devices have not the century, the :yeaivin »the- century, the-«monthi

succeeded in this is indicated by their _failure to displace from common use any appreciable num

ber of the ordinary calendars, notwithstanding the drawback of early obsolescence which these

in the year, .and the .day of - the vmenta-wis. given-l

by .certain -arithmetical rules. With vevery -da'y >ofà . the year,-beginmng-everyyea with January a-î

have. The various types of continuing calendars frequently found on the market arenot to `be con--` fused with a true perpetual calendar, since >they do not include within their own scalesall Ithe 45 ~

letter ‘can »-be«'associated,> A», B, repeating for consecutive days in1cyclical order, so that January v8 is always A again; January!! is"A B and so Won. ~ Only- ',ebruary 1129, .whenit occurs," hasno letter. 'Consequentlmin'a' non-leap-year

2,340,153 the other month cards are marked is believed to be apparent from the drawings. Each one of the year masks H10-|06 inclusive is provided with an opening |01 which is prefer ably rectangular in shape. The openings |01 are preferably of the same size in all the masks being indeed just large enough to expose all the rows

all the Sundays have the same letter, and this letter is called the “dominical letter” or “Sunday letter” of the year. The day of the week corre

4Sponding to any given date, whether Gregorian or Julian, can be computed by adding four in tegers, each no greater than seven, and taking the remainder, after the integral sevens have been removed from the said sum, to designate the day

of any successive seven of the thirteen columns or positions of day numbers marked on the month 10 cards hereinbefore described. '1 for Saturday. The opening of each successive year card is I shall call four such integers the “character staggered by the width of one column of the istic integers.” One of them is a function of the month cards; thus, opening |01 of year card |00 century year, differing in old and new styles. if the year card is placed properly over any one Another is a. function of the year in the century. Another is a function of the month, but for Jan 15 of the month cards will expose all of the rows of the first seven columns of day numbers; the open uary and February is changed by unity in leap ing |01 of year card |0| will expose the second, years from its ordinary values (unless, as is some of the week: as 1 for Sunday, 2 for Monday . . .

third, fourth, ñfth, sixth, seventh, and eighth col

times done, the leap-year difference is put on the characteristic integer for the year, this being then

umns; the opening |01 of year card |02 will ex

considered changed by unity during January and 20 pose the third through the ninth columns; the opening |01 of year card |03 will expose the February of "a leap-year as compared with its fourth through the tenth columns; opening |01 value during- the remainder of the same year).

The other integer is merely the day-number in _Y _ of year card |04 will expose the fifth through the -~ eleventh columns; opening |01 of year card |05 the month, or this number after the integral

sevens have been removed, as 3 for the 17th of the 25' will expose the sixth through the twelfth col month. The dominical letter for a given year __ a umns; and, opening |01 of year card |05` will ex pose the seventh through the thirteenth columns. corresponds to the sum of the characteristic in Each mask carries a scale |08 of days of the tegers for the century and the year in the century. » ` week in the normal order immediately adjacent With this arithmetical situation it is clear that any mechanical method of designating the four 30 one side of its opening |01. Each scale may com prise the ñrst letter of each day of the week; characteristic integers and adding them-.as step namely, S, M, T, W, T, F, S and the letters are by step by'a succession of sliders-will determine arranged so that the first letter registers with the day'of the week corresponding to a given date; the first exposed column of its year card, the sec WhileV a variety ,of devices for the purpose have been> described, Ysome ofl them many years ago, 35 ond letter registers with the second exposed col umn and so on. Instead of single letter abbrevi noneof them has all the advantages of compact ations, longer abbreviations or the full names of ness 4combined in> my device with the elimination the days of the week may be used in similar regis off-mental operations ‘and the preservation in all tration with the exposed columns. ' settings of the exact form of the kordinary `cal-’ It is preferable to mark each month card with' . .40 endar.

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the name of the month it represents and to arf range such marking so that the name of the

Referring particularly to'Figures'la. andj 1b of the- drawings, it' will be noted that` a` calendar ‘in corporating- the features of my invention may beA

month will be exposed through the opening of any one of the year masks.

made in the vform of'~ a‘plurality of cards;"more'

particularly, twenty-oneL cards, seven >of' which,

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month card in correct registration, it is preferable

|-00=|06 inclusive; are lyear-cards 'which' will 'be’

to make all of the cards of the same size. In this way when any year card is »placed face up exactly

referred to "herein" as "masks, and Ífourteen' lof-

which, |09;` |09','||0, llû’and lll-'|20 inclusive, are monthcards. `- The group of month-“cards |09,

|_|~0"‘and` ill-'|20 -inclusive lrepresent the/twelve’

over any one of the month cards seven columns 50 of day numbers will be exposed through the year

cardwindowv |01, said exposed seven columns. being designated by the seven days of the week marked on the mask while the unwanted six col-v

months of vany year other thandeap years while’

theV group of cards |09', Y»||||' and |||-|20 in#

clusive represent' in this particular embodiment, the-twelve months of any leap year.

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Each of the month cards is -provided with thirteen columns and six (December has seven) rows of Vday numbers, -the order of numbers, in cluding blanks, beingdiiîerent on each card,‘but4

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In order to simplify placing a year card on a

umns of day numbers are hidden. 55

. Each of the masks can be marked with theV

years for which it represents the correct setting, in other words, the correct designations of days of the monthA as days of the week. Since the Gregorian calendar repeats identically every 400 theïspacings being the same. ‘ Thus, month card 60 years, 2000 A., D.Vhaving the same calendaras |09> which is the card for January of all years 1600 A.‘D., 2001 as 1601, etc., it suffices for the except leap years, has no» day numbers in the Gregorian calendar to indicate only a consecutive first row positions of `the first seven columns,

series of 40o years.

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Below are shown the' years appropriate for each columns are numberedl through 6 respectively.A 65 year'maskfrom 1600 A. D. t'o ’2000 A.'D. inclusive in the Gregorian'system’; The appropriate year’ The_second row positions. of the thirteen columns. markingsV for each year card lmay be printed ‘on' are__numbered l14 through 13 respectively. The. however, . the . ñrst . row> positions of the` last »- six

third positions are numbered ,8 through ,20 re-. specti'viely and the Y fourth row- positions are

numbered 15 through 27 respectively. Theñfth

the -front and/or back of the card.

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- Each mask corresponds to all years which have 70 a certain one of the seven dominical letters, and

row positions, of the A first ten vcolumns are

numbered 22 through` 31 respectively and the sixth row positions of the ñrst three columns are numbered 29,r 30 'and' 31 respectively.

vThe manner 'in_which'the'bolumns of each'of . 75..

the proper letter. can be marked on eachyear`

mask. This marking has been shown in Figure. 1b on the left hand top corner of each year mask.E

The following table covers the years which are appropriateïqr eaçh'rear mask,

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2,840,153 Years appropriate for year

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above -table is placed over the 'month card |113 which is good for the month vof January 4o‘l‘ïïa'll

[Leap years-_are underlined]

those years except leap years.

1600 1651 1702 1

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Year mask 100.

standing thereof; it being only necessary to state that each ¿one vof the seven year masks,`only one

of which is shown at |2| in Figure 4, isprovided 10 with three openings |22, |23, and |24 represent ing a month, the preceding month, and .the :suc ceeding month, respectively; and -that each of

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YearmasklOl.

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the month cards |25 only one of which is shown

in Figure 3, is provided with three day number 15 charts |26, |21, and |28 representing> the >day numbers forone of the monthsk and the .day num bers for the preceding month and the succeeding month respectively. Obviously more than three 20

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Itis believed that a detailed description of vthe second embodiment of the invention `shown ¿in Figures 3, 4., and 5 is not necessary to an underf

1623 1673 1724 1775 1826 1876 1922

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months Because may of beexposed the overlapsiffrom desired. December . through ~

March there are four special month cardsfor leap-years, or sixteen month cards in allin the

Year mask 192.

embodiment In Figure> 5illustrated. there is‘shown the ' appearanceiof . '

25 acalendarsusing the- type of year masks and (D) f

Year mask 103. ‘ 1846

monthcardszshown in Figures 3 and 4. The Vexact arrangement is, of course, not significant; in# stead of showing the current month in larger type, a series of consecutive months printed in 30 the same sized type andimmediately adjacent each to each could be shown simultaneously ì through a large opening in a mask appropriate

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for the year.

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It is to be understood that none of the embodi~

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35 ments of the invention described are confined to

Year mask 104.

the system of chronological reckoning which pro-vides only one characteristic integer 0r dominical letter for a leap year while providing special

alternate characteristic integers for January and 40 February in leap years.

With equal mechanical

ease the system of a special integer for the ñrst two months of a leap year and another for the

(F) Year mask 105. 1946

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remaining ten can be used, with January and February always appearing with the same in-'g 45 teger. Suche, system permits reduction of the number of month scales from fourteen to twelvei but requires a double marking of the year cards as respects leap years.

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(G) Year mask 105A 1855 1900 1951

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The number of month scales can be further 50 reduced-to seven-if certain month scales are marked with the names of additional months ac

cording tothe following scheme-_Referring to

Figure la, let the card for January (common years) be marked also October; let January (leap `-'From the above it will be noted that in the em 55 years) be marked also April and July; let Febru ary (common years) be marked also March and bodiment shown in Figures 1a and 1b, the whole November; let February (leap years) be marked arrangement reduces to a pack of specially con also August; let May be marked May only; June, structed cards, therebeing fourteen month cards, June only; let September be marked also Decem and seven year cards, all of the same size if so ber; and omit thecards marked in Figure la, desired. When the proper year card is placed March, April, July, August, October, November, exactly over the proper month card, the opening and December. „This arrangement has, however, in the year card exposes the correct number of the disadvantage that day numbers 1-31 inclu, days for that month and year, in sequence, and sive are exposed for every month. l' having their correct designation as‘days of the 65 Of course, a reduction in the number of month week-the visible effect being exactly that of the 1962

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ordinary calendar.

The size of the resulting perpetual calendar ls

cards-but not in the number of scales-can be ' made by the obvious expedient of printing scales

not greatly increased as compared with an ordi

nary calendar having the same size printing or marking, and this is a special advantage of this embodiment.

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on both sides of the cards. Furthermore, the mask appropriate for years of dominical letter A, if reversed, is suitable for the G years; maskvB reversed for F years; mask C reversed for E1

years-Which device of turning the masks upside Figure 2 shows the way the calendar appears down reduces the required number to four. Only when the year card or mask |03 which is good ¿for the years noted in the fourth group of the 75 one mask indeed. is absolutely essential, if it lbe usable in' seven diiïerent positions so as to make

2,340# 53 ular position in one scale be designated as Sun day, the next one in order Monday, and so on through Saturday, .then if Vthese same designa tions are applied to the corresponding positions in certain others ofthe plurality of scales, the indications which result of the days of the week of all the months so treated will be correct in

its'opening expose any required consecutive seve'n columns of day numbers on'` the month scales; And again the role of the masks and the cards can be interchanged Without the loss ot all the

advantages of my invention-the masks being marked in the appropriate order, respectively,

with the combinations of months enumerated in years which have a certain dominical letter. ` the preceding paragraph, for example; and each 2. In a perpetual calendar, a series of seven card carrying a scale of vday numbers as already described marked not with a month or months 10 equi-sized templates, one for each dominical let ter, each marked at seven equally-spaced posi but instead with the years for which it is appro tions with the days of the week, in order Sunday, priate in combination with the masks Vwith mark ings thus altered.

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Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, without repetition, said scale of “days

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Furthermore, devices of this same general

character could be used, with appropriate 15 of the Week” on each template being adjacent to a Window which is the same size on all the tem changes, for any calendar that might be devised plates but differently placed in accordance with at all along the lines of the present Gregorian the dominical letter of the year for which the calendar. Say one with seventeen months of template is appropriate; and a series of at least Widely varying lengths and an .altered rule for 20 14 cards, each marked at thirteen equally-spaced leap years.

positions or columns with a scale'of “days of the

. It should be understood also that for Julian

month,” the interval between successive positions

dates the years would fall into diîferent sets, as compared with the Gregorian sets `already enu

being the same as between the positions of the days of the week on the templates: the size and merated. The Julian sets of years likewise can positions on the template of the window being be marked on the appropriate year masks, or 25 such that each template when placed in a stand indicated in a formula or table or correspon ard manner above any card hides six of the thir dences.

teen columns of Aday-numbers and exposes seven The number of patterns of each of the month consecutive columns thereof: the position of the cards shown in Figure la can be altered together in the following manner withouty essential dif 30 window from template to template in the series being different by the constant interval between ference; strike out the right-hand or thirteenth columns, so that each of the seven templates ex column of day numbers, and'substitute at the poses a different combination of seven columns, extreme left a new -column of day numbers hav but the same combination on every card, hiding :lng numbers less by unity than the present ñrst column of the respective month. For example, 35 all other columns on all the cards.3. In a perpetual calendar, a series of seven January (Figure la.) for common years when so substantially equi-sized templates, one for each altered becomes: dominical letter, a Window formed in each tem _ _

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plate, each template being marked adjacent its

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40 Window with “days of the week” indicia, in order

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Sunday, Monday, Tuesday, Wednesday, Thurs day, Friday and Saturday without repetition, all

of said Windows being of substantially the same size but diiïerently positioned on said templates repeated as many times as desired, provided all 45 in accordance with the dominical letter of the year for which the template is apropriate; and a the month cards are -changed together, and pro series of fourteen cards, there being an indi vided the cooperating change is made in the vidual card for each of the months of March, markings of the year masks; i. e., with the pattern April, May, June, July, August, September, Oc for January shown just above mask |00 (Figure 50 tober, November and December adapted for use' la) must be lettered G instead of A, and the years in any year, an individual card for each of the of its appropriate use are changed to correspond; months of January and February adapted for use masklûl must be lettered A instead of B; and so in leap years only and an individual card for on, mask |06 being lettered` F instead of G. each of the months of January and February ' What I claim is: . 55 adapted for use in common years only, each of » 1. In a perpetual calendar, a plurality of mem-v said fourteen cards being marked at thirteen bers bearing scales of “days of the month,” each equally spaced columns with “days of the month” scale being appropriate for a particular month indicia, the interval between successive positions and comprising at least thirteen positions of of said columns being the same as the interval day-numbers, a plurality of masking members cooperating with said scales each of,'said mask 60 between the successive positions of the “days of the week” indicia on the templates, the size and ing members being marked in a different position position of the window on each template being'v with a scale of “days of the week” and having-an such that each template when placed in a stand-Ä aperture adjacent to said scale for exposing seven ard manner above any one of said cards hides six_ successive positions of said- day-numbers,~l the seven markings of each of said scales of “days of 65 of the thirteen columns of day numbers and ex poses seven consecutive columns thereof, the po-A the wee ” registering respectively with the ex sition of the window from template to template posed seven successive positions of day-numbers, in the series being different by the constant in said thirteen positions of day-numbers being so terval between columns, so that each of the seven patterned that any seven successive positions in c_lude all the day-numbers of the respective month 70 templates exposes a different combination of seven columns, but the same Vcombination on4 and no other numbers and that successive day every card. , ' ' numbers in a single column differ by seven: the JOHN Q. STEWART. relation to each other of the number-patterns for

which thus agrees'in all respects >with the card

marked May in Figure 1a.

This process can be ,

individual months being suchthatl if. any partic- ’