US2146340A - Automatic calendar - Google Patents

Description

Feb. 7, 1939. z. JISKRA AUTMATIC CALENDAR Filed July 14, 1936 2 Sheets-Sheet l Feb. 7, 1939. f

Z. JSKRA.

AUTOMATIC CALENDAR Filed July 14', 193e 2 Sheets-Sheet 2 s K oRNEYs.

Patented Feb. 7, 1939 PATENT GFFICE AUTOMATIC CALENDAR Zdenk Jiskra, Prague-Strasnice, Czechoslovakia Application July 14, 1936, Serial No. 90,509

In Czechoslovakia March 30, 1936 13 Claims.

My invention relates to calendars and more particularly to an automatic calendar which indicates the full date and can be actuated by a single lever.

It is an object of my invention to provide for a device of the kind aforesaid which at any time displays the number and name of the day, the name of the month and the last figure of the year, and which, if connected with a clockwork,

l0 may also indicate the hour. On its back the calendar may furthermore alternately display the indications Forenoon and Afternoon.

It is another object of my invention to provide for a calendar of this kind which renders automatically visible indications corresponding to the different lengths of the months and of the leap years.

In a preferred modification particularly suited for the presently prevailing calendar-system, the

new calendar comprises five main discs which are provided with indications of parts of the' date and with openings for similar indications appearing on the other discs and which are formed on their circumferences with indentations and teeth. These teeth cooperate with a handor clockwork-operated lever in such manner that by a single movement of this lever performed at midnight all or part of the `discs are rotated to now display the next following date in the openlng of the front plate behind which the discs are arranged. The discs with their' inscriptions, openings and teeth may be shaped in such a manner that every second movement of the lever, to be effected at noon, does not change the date,

but only the Forenoon and Afternoon indication, while the movement then following changes the date, so that always the proper date appears on the calendar.

It is apparent that for any other commonly accepted calendar system this apparatus may be modified without exceeding the scope of the invention.

In the drawings affixed to this specification and forming part thereof one embodiment of my invention vin accordance with the present prevailing calendar system is shown diagrammatically by way of example.

In the drawings A Figs. 1-5 are front views of the discs I, II, III,

IV and V, respectively.

Fig. 6 is a front view of an intermediate ring plate VI which may be arranged between each pair of adjoining discs.

Fig. 7 is a front view of the front plate O, the

one quadrant thereof being omitted to show clearly on a corresponding number of the sectors the relative positions of the discs I-V to the ring plates VI.

Fig. 8 is a front view of an automatic calendar embodying this invention driven by a clock work. I

Fig. 9 is a side elevation, partly in section. Fig. 10 is a rear view of a calendar after the clockwork has been removed therefrom.

Figs. 11 and 12 show in a front elevation and a plan View, respectively, on a larger scale, a 10 spring catch for engaging the teeth of the discs.

Fig. 13 is a perspective View of the casing, showing the mounting of the intermediate ring plates. Referring to the drawings, O1 is the back cover of the calendar which is formed with a circum- Il ferential recess or opening M and an oblong, horizontally arranged opening P4 for displaying the indications Forenoon and Afternoon, O is the front plate formed with three openings: the oblong, horizontally arranged opening P1 for the 20 number of the day and the name of the month;

`the similarly arranged opening. P3 for the name of the day, and the smaller opening P2 for the unit of the years. Q is aclock-work mounted on the back cover O1. 25

Between the front plate and the back are' concentrically arranged the five main discs, in the following sequence: I, II, III, IV, V. The five discs are loosely mounted on the hollow journal U traversing the centres of the front plate O and 30 the cover O1. Between the discs are arranged intermediate ring plates VI shaped as flat circular rings (Fig. 6) which do not rotate about the journal U, but merely separate the discs from each other and from the front plate and cover 35 plate. The annular intermediate ring plates VI are secured against rotary displacement by projections N1 abutting against the edges of the recess M of the cover O1 and are formed with` recesses M in which the catch Z may slide. These 40 recesses are formed with an exact profile, while the prole of the recess M of the cover O1 may differ therefrom to a' certain extent (Fig. l0). More particularly the manner in which the intermediate ring plates VI are mounted between the 45 discs I and V is shown in Fig. 9. An opening is cut out in the lower face of the cylindrical part of the back O1, as shown in Fig. 13, having the edge M cut out to clear the notched portions M1 of the intermediate ring plates. 50

The intermediate annular plates VI are not fixed in the casing, but only tightly inserted as shown in the upper part of Fig. 9. Those parts of these annular plates, in which the recesses are arranged, project beyond the lower part of the 55 .casing, so that the annular plates are securedr against turning. The ring plates do not require any securing means to prevent axial movement.

When the parts are assembled, a ring plate y VI is first inserted against the inner side of the back of thecasing, as shown in Fig. 9 (with the front plate O removed) then disc V is assembled on the bearing collar U, thereafter another ring plate VI is inserted in the casing, then disc IV and so on to complete the assemblage.) While the ring plates VI are inserted in the casing so as to be immovable, the discs I to V are freely rotatable therein.

, Thus all intermediate ring plates VI inserted in the casing are secured against turning by the projections N1, engaging the circumferentially spaced edgesin the bottom opening of the casing. The lugs N1 are not bent but project only a slight distance beyond the peripheries of the ring plates VI. The discs carry marks or inscriptions, signs, words or abbreviations and/or gures and, besides, openings Lr-L4, through which, the inscriptions of the lower discs can be read. The inscriptions and openings are arranged in such manner that in every correct position the openings and inscriptions of the single discs behind the three openings of the front plate form a full date. On their circumferences all discs are pron vided with teeth of unequal height, the depths of the notches between the teeth being unequal also. The heights of the teeth and depths of the notches between the teeth are dened by nine concentrical circles A, B, C, D, E, F, G, H, J.

To each self-contained inscription of a disc is, allotted one tooth of the same disc.

Disc I as shown Ain Fig. 1 is circumferentially divided into fourteen parts, two for each day. It carries the names of theseven days of the week and seven openings L1 enabling one to read the numbers of the days, the names of the months and the units of the years marked on the other discs. On itsv circumference it is formed with seven teeth 1-7.

Disc II as shown in Fig. 2 is circumferentially divided into twenty-live parts, two for each month, but three for the month March. It car--` ries twice the name of each month and three times the name March. Near the first name of each month (except March) the disc is solidv and carries the inscription f1.; near the second name (except March) the disc is formed with an opening L3 allowing the number of the day to appear in theopening P1 of the front plate. The opening L3 belonging to March is next to the third occurrence of the name of this month, whereas next to the second occurrence the inscription 2. is found. The disc is further formed with twenty-five openings Lz, one next to each of the names of the months, allowing the units of the years to be lread. through the opening P2 of the uresA 1-31 and is formed with thirty-one openings L4 for the units of the years. On its circumference it carries thirty-one teeth l-31, details of which will be described further below.

Disc IV as shown in Fig. 4 is circumferentially divided into twenty-ve parts. It carries the following sequence of figures: 1, 2, 3, 3, 4, 5, 6, 7, 7, 8, 9, 0, 1, 1, 2, 3, 4, 5, 5, 6, 7, 8, 9, 9, O, in correspondence to the units of the years, wherein each figure which follows that of a leap year, is

doubled. The disc carries on its circumference tWenty-ve teeth 1-25 the details of which will be described further below. It need not be formed with an opening.

Disc V as shown in Fig. 5 is circumfcrentially divided into eight parts. On its back side, which is directed towards the cover Oi, it carries fourV times in alternation theinscriptions Forenoon and Afternoon. On its circumference it carries eight teeth, the details of which will be described further below. No opening need be provided therein.

'Ihe outline or profile of the teeth and notches is dened by the points of intersection of the circles A, B, C, D, E, F, G, H, J with the radial lines or rays 1, 2, 3, etc., the number ofv which on each disc corresponds with that of the circumferential teeth. On the back of the calendar, i; e. on the outer side of the cover O1, is loosely arranged on the pin R the flat lever Y which is provided with the flat spring pawl Z shown in Fig. l1. The end of lever Y is bent at in such manner that it is perpendicular to the plane of the discs; the end engages the recesses M1 of the annular ring plates VI located between the discs.

The device operates in the following manner:

The teeth and notches `of the concentric discs partly overlap each other. During a clockwise movement of the lever Y the pawl Z only catches the highest teeth of each combination of the discs, thus rotating only the discs belonging to those teeth, while the other discs remain at rest. The pawl Z carries the teeth along only until it reaches the edge lc-l ofthe recess M1 where it stops, so that the active edge of one tooth of each disc when at rest, coincides with said edge l-Z.

The recess Mr is'formed in the intermediate ring plates VI or in one of them with great exactness, while in the other intermediate ring plates VI as well as in the back it has only an approximate, but at any rate'not narrowed form, as -follows: y

All the teeth while being formed on one side with an active edge for coaction with the pawl Z,

are formed on the other side with a slanting edge ylor the cover O1, respectively. The circular length of the recess is somewhat more than 1/7 of the circle B in order that with every second movement in the operating direction the pawl Z can grasp a tooth of the disc I. The inner edge ofthe narrow part of the recess M is delimited from point f to point g by the circle B. Point g is the point of intersection of this circle B with that radius which is separated from the edge lc-l by 55 of the circumference of the circle B. The

inner delimitation of the recess then runs from 75 point g to point h which is the point of intersection of the circle D with the radius separated from the edge Ic-l by $431 of the circumference of y the corresponding concentric circle. The delimitation leads further from point h to point J' which is the point of intersection of the circle J with the radius separated from the edge lc-l by $55 of the circumference of the corresponding concentric circle. The edge of the recess then follows the circle J to the radial edge lc-l.

As to the movements of the lever Y, oscillations changing the date and being intended to be carried through at midnight alternate with oscilalations which only change the indication Forenoon into Afternoon and are intended to be carried through at noon; for disc V is shaped so that on its circumference deep and shallow notches alternate. In a deep notch the pawl Z is enabled to engage teeth of the other discs, thus changing the full date, whereas in a shallow notch the pawl remains in its raised position and does not effect any change.

The adjusting and changing of the single indications proceed in the following,A manner, provided that one of the deep notches of disc V is in the operative position:

(1) Normal changes of the calendar dae` in the course of a `month These normal changes are brought about for all days between the fourth and the twenty-eighth of every month. In this case only the teeth on the disc III which are delimited by the circles D and E, (from tooth No. 28 to tooth No. 4) come in engagement with pawl Z. When the pawl Z proceeds from f to the edge k-Z, it rst slides on the edge f-g, being resiliently pressed onto this edge, and first catches the teeth ofthe discs I and V. It is not yet capable of catching' the teeth of the other discs, since they are"ra`dially lower than the solid part, delimited by f-g, covering these lower teeth. Beyond the point g the pawl Z passes onto the outer edge of the tooth of disc II, which outer edge lies in the circle B. Pawl Z cannot catch this tooth since the active edge of this tooth is separated from the edge k-l by two teeth of disc II, i. e. by $125 ofly the circumference, so that the upper active corner of the tooth extends beyond g. Pawl Z therefore glides on the outer edge of the tooth of disc II and slips off its slanting edge, being pressed by its ownelasticity onto the circumference of disc III. During further movement of the pawl, it meets the tooth of disc III, catches it and carries the teeth of the discs I and III beyond the edge lc-I, so that the active edges of these teeth coincide with the edge Ic-l. Since to the tooth of disc I corresponds the name and to the tooth of disc III the number of the day, the date within the month has thus been changed. The name of the month has not been changed, since the tooth of disc II has not been moved.

(2) changs of the months After the 28th, 29th, 30th or 31st day, respectively, the month is changed and in the perforation of the front plate O appears the name of the following month land at the end of a year also the number of the following year. For every year there must be effected twelve changes of this kind; they may be divided into four groups in accordance with the length of the months.

(a) Operation of the calendar at the end of a month with 31 days, for instance January:

On the 28th of January the tooth No. 29 of the disc III, which tooth corresponds to the 29th day, is prepared for the following engagement by the pawl Z. The tooth No. V30, however, is higher than No. 29 and therefore overtops the edge g--h, so that with the following movement of lever Y the pawl Z would catch this tooth No. 30 and carry along two teeth of the disc III. However, this does not happen, because the tooth III, 30 is covered by the tooth No. 3 of disc II which remains at rest up to the 31st day. Beyond the tooth DI, 29 however the tooth II, 2, being otherwise free for engagement, is not caught by the pawl Z, because the notch following the tooth III, 29 is not deep enough.

On January 29th the tooth III, 30 is prepared for engagement. The following tooth, which is still higher, l. e. tooth III, 31, is covered by the I tooth II, 3.

On January 30th the tooth III, 31 comes into position to be engaged by pawl Z upon the next movement thereof at midnight at the end of this day. "I'he tooth III, Iis still covered by the tooth On January 31st the tooth III, 1 is engaged, which corresponds to February 1st, tooth III, 2 being stillcovered by the tooth II, 3. As'the notch in disc III beyond the tooth III, 1 extends down to the circle J, the pawl Z descends until itA meets the tooth II, 2, which is now uncovered. 'Ihe pawl Z now carries along the discs IIand III, and the'. date changes to the first of February. Now being located directly behind the tooth III, 2 the tall tooth II, 3 is prepared for engagement. When changing over to the second of February, this tooth is carried along so that in' the opening'of the front plate appears the second inscription February, and the opening L3 next to it of disc II; this second inscription February remains visible up to the end of February, because the following tooth II, 4 has come in the `position of engagement, which tooth is lower than the deepest point of the notch between the following teeth of the disc III. The teeth of the disc III, which correspond to the third and the later days of February, are low, so that the pawl Z is only capable of catching one tooth at each oscillation, although in the month of February no tall tooth is in position on the disc II between II, 3 and II, 8 which would exceed and thus cover the edge g-h during themonth of January.

(b) Operation of the calendar'at the end of a month with 28 days; for instance February of a normal year.

On February 28th, the tooth III, 29 is ready for engagement, but the following tooth III, 30 is higher and overtops the edge g-h, so that the pawl Z, while moving further grasps this tooth and causes the disc III to rotate to the extent of two teeth, since disc II is only formed with l1 tall teeth like II, 3 which work as described in the last paragraph, whereas tooth II, 5 is too low for such action. Consequently the 30th of February would now'appear in the opening of the front plate. Since, however, the notch between the teeth III, 30 and III, 31 extends down to the circle F, while tooth II, 4 extends up to the circle E, the pawl Z, after having slipped into the notch between the teeth III, 30 and III, 3l, will grasp also the tooth II, 4 and rotate the disc II to the extent of one tooth; there' now appears in the opening of the front plate the full inscription A Z, since tooth II, 6, like II, 5, is too low to cover it, the disc III being again rotated to the extent of two teeth, whereby the number of the rst day is carried behind the opening of plate O. Simultaneously the tooth II, 5 is carried along, so that in the opening appears the date 2. March, while the disc III is covered thereby.

On March 2nd the tooth IH, 3 is brought into position, which tooth, although not being higher than the edge g-h, is drawn a little beyond the corner h, because the tooth III, 1 by means of which the disc had been adjusted fory the preceding date, is formed at the top with a step against which the pawl Z abuts, so that the disc',

III has been pushed forward by a little more than J/l of the circumference and the tooth III, 3 has been drawn alittle beyondthe corner h. The pawl Z had made contact with the step of the tooth III, 1 because it was prevented from slipping below it by the too shallow notch between the teeth II, 5 and II, l6. Now the pawl Z, while moving further, catches the teeth III, 3 and II, 6, whereby the number 3 of the day of the disc III and the word March and the opening for the numbers of lthe days of the disc II appear in the opening of the front plate. During these changes also the discs I and V have revolved.

The changes of the date which now follow are similar to those described above under (1) (c) Changes at the end of the month of February with 29 days, viz. in a leap year.

In this case the influence of the third disc, i. e. the disc IV for the units of the years,comes into action. In consequence of the arrangement of the gures on disc IV, described above, after each twenty years period, i. e. after one full rotation of the disc IV, the same conditions prevail again. Therefore the operation of the disc IV in accordance with the rules of the calendar is not limited in time. The disc IV will only fail in the case,- where a number of a century is not divisible by 400 (as for instance the number 1900) so that this year, in spite ofits being divisible by 4, is not a leap year. In this case the date on the calendar must be manually adjusted from February 28th through February 29th to March 1st.

The disc IV is formed with ve sets of teeth, each set consisting of four short teeth and one long tooth. Three of the short teeth of each set correspond to the three ordinary years whereas the'other short tooth and the long tooth of each set correspond to leap year. The long teeth are l somewhat similar to those of the disc II; they are however lower by one circle, extending only to the circle C, and lacking the laterally projecting points or corners described above.

The change takes place in the following manner: On February 28th the tooth III, 29 is 'ready for engagement. The 'following tooth III, 30, which overtops the edge r1-h, is covered by a higher tooth of the disc IV, so that the pawl Z only grasps the tooth III, 29 and brings February 29th into position. Now the tooth III, 31 overtops the tooth of the disc IV; in the following change of date the pawl Z therefore grasps the tooth III, 31, thus rotating the disc III again to the' extent of two teeth ,and causing the number of f the 31st day to appear.Y The notch between the teeth III, 31 and I II, l is so deep that pawl Z carries along also the tooth II, 4, whereby the date 1. March, all on disc II, is brought into view and covers the inscription of the disc III in the opening of the front plate. Now the tooth of disc IV is overtopped by the tooth III, 2, which is carried along together with the tooth II, 5 in the following change of date. On disc III now appears the number 2, on disc II the date "2. March. y

In the following change of date only the tooth III, 3 is grasped, for the tooth III, 4 is so low that it is already covered. At the same time the tooth II, 6 is carried along, whereby the date 3. March is produced. The following changes of dates are normal as described under (1).

(d) Changes at the endofl a month with 30 days, for instance April:

A short tooth of the disc II corresponding to a month of 30 days and producing the change, for instance the tooth II, 9, which is provided for the changing over from April to May, is higher by one circle than the corresponding tooth of the same disc which is provided for a month with 31 days. tweenthe teeth III, 31 and III, 1 which corresponds to the number of the 31st day. While the pawl Z moves, the disc III rotates in the normal way to the date 31, but tooth II, 9 is also moved, whereby the inscription of the disc III in the opening P1 of the front plate is covered by the inscription r1..May. The tooth II, 10 which, before this, covered the higher teeth of disc III, and spaced 5/31 from the edge k-Z of the disc III, has now been moved forward by j/25 of the circum'ference, whereby the ,tooth III, 2 has been uncovered. In the following change the pawl Z drives the tooth III, 2 bringing thereby the number 2 of the day within the opening P1, and the tooth II, 10 pushing behind the opening of the plate O the other inscription May and one of the openings La, through which the number 2 can be read.

The now following changes of the date are normal as described under (1).

(3) Changes of the years (a) Normal year: On December 31st there are in position on the -discs III and II the deepest notches, viz. the

notches between III, 1 and III,2 and between II, 25 and II, 1, respectively. In the changing over from December 31st to January -1st the pawl Z drops down until it reaches the teeth of disc IV, which carries the unitsv of` the years, 'bringing about a rotation of this disc to the extent of one tooth to display the unit of the following year.

(b) Leap year:

For a leap year a tall tooth of the disc IV is adjusted to overtop the edge g-h. To the end that this tooth may be shifted behind the edge lc-Z, the change of the year must be carried through the two parts. The pawl Z grasps, during the changing over to January 1st, of the year following a leap year, in the notches III, l-III, 2 and. II, 25-II, I' a low tooth of the disc IV which precedes a high tooth, and during the changing over to January 2nd it catches this high tooth. For this reason the disc IV carries twice in succession the units of the years, which follow a leap year. Thereafter the normal state is established again.

I arrange the inscriptions on the discs in a well defined manner in order that they appear exactly in the openings of the plate O.

In the calendar illustrated in the drawings the -straight line a, b, c is the longitudinal axis ofthe openings P1 and P3, which form a part of the opening of the front plate (see Figs. 1 and 8).

It therefore overtops already the notch be- The production of the edge k-l to the point b,

which need not necessarily be the centre of the disc O, includes with the straight line a, b, c an angle r. Therefore every inscription on the discs, which marks a day or month, is arranged in an axis which on the disc, on which this inpendicular to lines which include with the produced active edges oi.` the teeth, which must be engaged to display the single units, the angle 1'; the same is true of the transverse axis of `the inscriptions Forenoon and Afternoon on disc V, where the angle s is a right angular one.

The calendar may easily be combined with :a clock, for instance as shown in Figs. 1, 2 and 3. The front plate is formed as agdial, and the spindles carrying the hands traverse the hollow journal U. The clock-work Q of some usual kind, may be fixed with its casing to the back of the calendar and may be provided with means for actuating the calendar twice a day, preferably at midnight and noon. Such means may comprise a pin R attached to the back of the calendar or of the clock-work or its casing. On this pin is mounted for free pivotal movement the flat lever Y which car'ries on its one end the resilient pawl Z. Spring means R1 are arranged to press the lever Y with the pawl Z towards the edge lc-l. By the pin S the lever Y abuts against the spiral cam member X which is rigidlly mounted on the shaft of the short hand of the clock and thus performs one complete rotation Within twelve hours.v During this rotation the member X lifts the lever Y towards the point f; at twelve oclock the outer end of the cam comes to lie against and to slip o, the stop S, whereafter the lever Y, pressed by the spring R1, moves with the pawl Z towards the edge k-L the full date or the forenoonafternoon-indication being now changed. In order to prevent the lever Y from moving too rapidly, I provide an edge v along which the stop S, after being freed from the cam, is forced to slide; the edge v lies between the two ends of the spiral cam member X and differs slightly in form from the circle. m, the centre of which is the pin R, as may be seen in Fig. 3.

Should the clock stop,` for instance when not wound up, the date may be manually adjusted by shifting the discs in the openings by the aid of a needle or the like. After the date has been so adjusted and the clock wound up, the calendar again operates in a perfectly automatic and reliable manner.

As mentioned above, the calendar will operate infinitely without any correction being required except in a century, the number of which is not divisible by 400. If this correction shall also be avoided, the form of the teeth must be altered gorrespondingly.

I wish it to be understood that I do not desire to be limited to the exact details of construction shown and described for obvious modifications will occur to a person skilled in the art.l

I claim:-

l. An automatic calendar for manual or mechanical adjustment of the dates comprising in combination, a front plate with an opening therein, a back, discs concentrically mounted be- .hind and substantially parallel to said front plate for free rotation about a common axis, an intermediate ring plate secured against rotation between two of said discs, said intermediate ring plate having a recess with a profiled edge, while said discs have openings formed therein and inscriptions for the display of a date, behind said opening of the front plate, profiled teeth of diiferent heights on the circumference of said discs for overtopping in turn the profiled edge of the recess of said ring plate, notches of different depths being formed in the discs between said teeth, theL teeth of one disc being partly overlapped by and partly. overlapping those of another disc, and means for periodically rotating one or more ofV said discs comprising a pawl adapted to slide in `said recess and being resiliently pressed towards the profiled edge of said recess to carry along those teeth, an edge-0f which is inposition to be engaged by it.

2, Automatic calendar for manual or mechanical adjustment of the dates, comprising in com- ,bination, a front .plate with an opening therein,V

a back, discs concentrically mounted behind and substantially parallel to said front plate for free rotation .about a common axis, an intermediate ring plate secured against rotationbetween two of said discs, said intermediate ring plate havlng a recess with a profiled edge, while said discs have openings and inscriptions for the display of a date, behind the opening of the front plate, pronled teeth of different heights on the circumference of said discs for overtopping in turn the profiled edge of the recess of said ring plate, said discs having notches of different depths between said teeth, the teeth of one disc being partly overlapped by and partly overlapping those of another disc, and means for periodically rotating one or more of said discs every twelve hours comprising a clock-work and a pawl adapted to slide in said recess and being resiliently pressed towards the proled edge of same to carry along those teeth, an edge of which is in position to be engaged by it.

3. Automatic calendar for manual or mechanical adjustment of the dates, hours and times of day comprising in combination, a clock, a front plate with an opening therein forming also the dial of said clock, a bach which has formed therein an opening, a hollow journal between said front plate and said back, a shaft arranged in said hollow journal to carry 'a hand of said clock, discs concentrically mounted behind and substantially parallel to said front plate for free rotation about said hollow journal, an intermediate ring plate secured against rotation about said journal between two of said discs, said intermediate ring plate having a recess with a prolled edge, while said discs have openings formed therein and inscriptions for the display of a date, behind the opening of the front plate and to the rear of the opening of said back; proled teeth of different heights on the circumstance of said discs for overtopping in turn the proled edge of the recess of said ring plate, notches of different depths being formed in said discs between said teeth, the teeth of one disc being partly overlapped by and partly overlapping those of another disc, and means controlled by said clock i'or periodically rotating `said discs comprising a pawl adapted vto slide in said recess and being resiliently pressed towards the profiled edge thereof to carry along all 'thosev teeth, an edge of which is in position for engagement.

4. Automatic calendar for manual or mechan-` ical adjustment of the dates in accordance with the present prevailing calendar-system comprising in combination, a front plate with an opening therein, a back which has an opening formed vso therein, ive discs concentrically mounted behind and substantially parallel to said front plate for free rotation about a common axis, an intermediate ring plate secured against rotation between two of said discs, said intermediate ring plate having a recess with a proled edge, while said discs have openings and inscriptions, for the display of a date, behind the opening of the front plate and to the rear of the opening of the back, proiiled teeth of diierent heights formed on the outer edge of said discs for overtopping in turn the proiiled edge of the recess of the back, the number of teeth on each disc being equal to that of the inscriptions arranged on this disc, notches of different depths being formed in said discs between said teeth, the heights of said teeth and the depths of said notches being defined by points of intersection of nine concentric circles, the centres of which lie on said common axis, with radial rays which define the active edges of said teeth, the teeth of one disc being partly overlapped by and partly overlapping those of another disc, and means for periodically rotating said discs comprising a pawl adapted to slide in said recess and beingy resiliently pressed towards the proled edge of the same to carry along all those teeth, an edge of which is in position for engagement. l

. 5. 'I'he automatic calendar of claim'4, in which the irst disc bears seven inscriptions, one for each day of the week, seven teeth being formed on its circumference and openings formed in said disc between the inscriptions adapted to display in the opening of the front plate the inscriptions arranged on some other disc.

6. The automatic calendar of claim 4, in which the second disc carries 25 inscriptions, two in succession for each month of the year other than March and three in succession for the month of March, 25 teeth being formed on its circumference and marks indicating the first day of every month arranged next to every rst of said marks for each-,of the months, said disc having openings formed therein one arranged next to every second mark for each of the months other than March and one next to the third mark for the month of March, these openings being arranged to display in the opening of the front plate the inscriptions carried by the third disc, and openings formed in said second disc, one arranged next to each of said 25 inscriptions vadapted to 'display in the opening of the front plate the inscriptions carried by the fourth disc.

'7. The automatic calendar of claim 4, in which the third*r disc carries 31 figures for the days of the'month, and is formed with openings adapted to display in the opening o f the front plate the inscriptions carried by the fourth plate, 31 teeth being formed on thecircumference of said third disc.

8. The automatic calendar of claim 4, in which the fourth disc carries 25 figures, viz. twice in succession the series of gures from zero to nine, wherein the figures 3 and 7 in the one succession, and the iigures 1, 5 and 9 in the other one are repeated, and 25 teeth on the circumference of said fourth disc.

,9. The automatic calendar of claim 4, in which the fth disc is formed with eight teeth on its circumference and carries on its back four marks for forenoon in alternation with four marks for afternoon, each of these marks being adapted to register with the opening in said back so as to be visible therethrough.

10. The automatic calendar of claim 4, in which eight teeth are formed on the circumference of the fth disc, the notches between these teeth extending alternately `down at least to the innermost of the nine circles and only to the outermost one, the said iifth disc having four marks on the back for forenoon in alternation with four marks vfor afternoon, each one of these marks being adapted to register with the opening in said back so as to be visible therethrough.

11. The automatic calendar of claim 4, in which the circles are lettered for reference from A to J, omitting the letter I, beginning with the outermost circle in/ which the intermediate ring plate is formed with an outer recess, one edge of which is formed by part of a radius of said circles, while its inner delimitation extends from the point of intersection of the radius andthe innermost of said circles, following this circle for 1/25 of its circumference extending from here right to a point on the circle lettered D spaced from said radius 3&1 of the circumference of the circle, from this point to a point on the outermost but one of said circles spaced from said radius 9&5 of the circumference of the circle thereafter following this latter circle until it reaches a point spaced from said radius 1/1 of the circumference ofthe circle and then extendingv tothe outermost circle, meeting thesame at a point spaced from said radius a little more than V7 of its circumference.

12. The automatic calendar oi' claim 3, in which the means for periodically rotating the discs comprise, apart from the pawl, a pin carried by the back and arranged outside the center of said back, a lever mounted for free rotation about said pin and carrying said pawl, spring means for pressing said lever with said pawl towards a radial side edge of the recess in the intermediate ring plate, a pin carried by said lever and a spiral member against which abuts said pin and which is arranged to rotate in conformity with the shaft of the short hand of said clock and to force said lever against the action of said spring means with said pin away from said centre, releasing it every twelfth hour for guiding said pawl at once through said recess towards the radial edge of the same.

13. The automatic calendar of claim 3, in which the means for periodically rotating the discs comprise, apart from the pawl, a clockwork carried by thekback, a pin carried by the back and arranged outside of the centre of lsaid back, a lever mounted for free rotation about said pin and carrying said pawl, spring means for forcing said lever with said pawl towards a radial side edge of the recess in the intermediate ring plate, a stop associated with said lever and a member having a spiral edge, against which abuts said stop', said member being arranged to rotate in conformity with the shaft of the short hand of said clock and to force said lever with said stop against the action of said spring means away from said centre, releasing it every twelfth hour for guiding said pawl at once through said recess towards the radial edge of the same, and said member having a curved edge connecting the two ends of said spiral edge for guiding said stop, whenvreleased by said member, with reduced speed.

ZDENK JIsKaA.

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