GB2323185A

GB2323185A - Perpetual calendar mechanism for clocks watches and timers

Info

Publication number: GB2323185A
Application number: GB9704920A
Authority: GB
Inventors: Souza Paul Gerard D
Original assignee: SOUZA PAUL GERARD D
Current assignee: SOUZA PAUL GERARD D
Priority date: 1997-03-10
Filing date: 1997-03-10
Publication date: 1998-09-16
Anticipated expiration: 2017-03-10
Also published as: GB9704920D0; GB2323185B

Abstract

A perpetual calendar mechanism comprises a day wheel 1 toggled once a day by wheel 14 and intermittently co-operable with a month wheel 3 via a sector gear2, intermittently driving the same by 1/12th of a revolution for every revolution of the day wheel. The driving takes place during the end of month period of the day wheel. The month wheel has supplementary teeth of a quantity and position corresponding to the number of days less than 31 at each month end. The teeth are driven by wheel 11 so as to advance the month wheel and in turn the day wheel to compensate for months with less than 31 days. One tooth is provided by gear 5 and is omitted during every 4th turn of the month wheel for a leap year.

Description

PERPETUAL CALENDAR MECHANISM for clocks watches & timers.

This invention relates to a perpetual calendar mechanism particularly suited for indicating or displaying the month and date automatically on mechanical clocks, watches & timers.

Calendar mechanisms are useful additions to common mechanical or quartz clocks and watches. Most calendar mechanisms are particularly designed to display the month and date as an additional feature to the basic timing function of mechanical clocks and watches. The date and month are usually displayed in separate windows on the clock face or dial, or with the help of an auxilliary dial or dials. These mechanisms are usually kept simple in design and need correction during months with less than 31 days and almost certainly during leap years.

Perpetual Calendar mechanisms are mechanisms that are designed with a self correcting date and month display that needs no manual intervention at the end of every short month as well as during leap years. Perpetual Calendar mechanisms are very complex incorporating numerous cams, gears, levers, ratchets, springs, clicks etc. and are very expensive to implement on a commercial scale and are hence not very common.

Perpetual Calendar mechanisms, in most cases, derive their motive force from the Watch or Clock train and consume a considerable amount of power. This results in additional difficulties of timing accuracy and power requirements.

In addition there are relatively few Rotary designs wherein a calendar is implemented mainly with the help of gears as opposed to with levers, cams, ratchets etc. A rotary design enables the movement to work more efficiently than a movement using levers, cam wheels, clicks, racks etc. A rotary design is in most cases more efficient and easier to manufacture than a non rotary design.

The object of the present invention is to provide a Perpetual Calendar mechanism that is 'ALL ROTARY' in design or containing mainly revolving components for its functioning.

According to the present invention there is provided a date wheel with 31 teeth that is toggled by one tooth once every 24 hours, thus serving to indicate the date. This date wheel in turn drives another month wheel ( via auxilliary sector gearing ), that is divided into 12 major divisions that serve to indicate the 12 months. Means for driving the month wheel directly is provided so that the month wheel can be advanced separately at the end of the short months. Means are provided on the month wheel to indicate the shortfall of days (if any) for each month respectively, as well as a means to vary or alter this system of encoding for the month of February every fourth year or leap year.

A specific embodiment of this invention will now be described by way of example with reference to the accompanying drawings wherein Figure 1 is a an 'exploded' plan view of the various essential components of the invented perpetual calendar mechanism.

Figure 2 is a composite plan view of the assembled components in actual possible layout showing the cooperation of various gears and components.

Figure 3 is the elevation section of the various components shown with respective gears in proper height elevation depicting the sequence and order of meshing gears. Wheels (11),(12),(13) & (14) are shown axially displaced at their proper elevation. the location is displaced only for graphic clarity. Wheels (11) & (14) are depicted meshing with (3) & (1) respectively. However wheels (13) and (12) need to mesh with one another as depicted in Figure 1 & Figure 2.

Figure 4. Depicts the angular contact over 4 days between wheels (1) & (3) and (2) & (4). Figure 4 also shows the teeth representing the transition of dates 28-29, 29-30, 30-31, 311, as well as month representation during the said transition sequence.

With reference to Figures 1 & 2, the Perpetual Calendar Mechanism comprises a thirty one tooth date wheel (1) that is toggled once every twenty four hours by finger (14) mounted on day wheel (13). Day wheel (13) makes one complete revolution a day and is driven by a clock, watch or timer mechanism which supplies the motive force to the mechanism.

Date wheel (1) makes one complete revolution in thirty one days and hence is used to display the current date.

Month wheel (3) is divided into forty eight divisions wherein each month is represented by four divisions, with each month indicated sequentially as depicted on wheel (3) in Figure 1.

These four divisions serve to indicate the first to twenty eighth, twenty ninth, thirtth, and thirty first of any months respectively. The months with less than thirty one days are indicated by the presence of one or more teeth on wheel (3), one tooth for each day less than thirty one. This is clearly depicted by (3) in Figure 1. However for the month of February, a tooth to represent the twenty ninth day is replaced by a relocatable tooth provided by wheel (5). If wheel (3) had a fixed tooth instead to represent the twenty ninth of February, the Calendar mechanism would still work as a three year calendar. It would need to be reset on the first of March every leap year.

The teeth on wheel (3) also serve as a means to directly toggle or advance month wheel (3) at the end of short months by as many teeth as there are on wheel (3) for that particular month. This is accomplished by the three tooth wheel (11) that is positioned to mesh with the teeth of wheel (3). Wheel (11) is provided to provide a rapid advance of wheel (3) at the end of a short month and is easily implimented by driving wheel (12) off day wheel (13). Positional steadying or locking of wheel (1) and wheel (3) is accomplished using spring clicks (24) and (25) respectively as depicted in Figure 1.

An essential requirement is that wheel (1) and wheel (3) move in synchronism with each other over the last four date transitions as represented on wheel (1) and wheel (3) in Figure 1, and as described by (A) and (B) in Figure 4, which show the respective arcs of cooperation required by wheel (1) and wheel (3).

This is accomplished by sector gear (2) fixed co-axially and rigidly to wheel (1), which meshes with wheel (4) that is fixed co-axially and rigidly to wheel (3). Thus for every one complete revolution of gear (2), wheel (4) will make one twelveth of a revolution. This also serves to advance wheel (1) by toggling wheel (3), or to advance wheel (3) by toggling wheel (1) during the last four days of any month.

The last four date transitions specifically refer to the date transitions between twenty eight to twenty nine, twenty nine to thirty, thirty to thirty one, and thirty one to one with reference to the end of one month and the begining of another.

The teeth on the wheel (3) are so positioned that there is no tooth corresponding to days 1 to 28 ( both days included).

The sector gear (2) and wheel (4) mesh on the twenty eight to twenty nine day transition moving the date to twenty nine and the month wheel (3) to the twenty nine / thirty position. If the month is a thirty day month, there is no corresponding tooth on wheel (3) and nothing happens. After another twenty four hours the date date wheel (1) is toggled by finger (14) by one tooth from thirty to thirty one. Since wheel (4) is in mesh with the date wheel (1) via gear (2), it moves by one tooth to the thirty / thirty one position. If the month is a thirty day month, wheel (3) has a tooth representing the thirty first day. This tooth now meshes with wheel (11) causing wheel (3) to be advanced by another division to the first of the next month. Wheel (1) is also simultaneously advanced to the first and then sector gear (2) moves out of mesh with wheel (4) for the duration of the next twenty eight days. If the month is February then wheel (3) has three teeth (or two teeth during a leap year) representing the last three days of that month, causing it to be advanced by wheel (11) by three divisions (or two divisions during a leap year).

e To effect a change of number of days from twenty eight to twenty nine, and hence the number of teeth on wheel (3) for the month of February, a three tooth wheel (5), with teeth on three consecutive quarters and one blank quarter,is fitted on a Maltese Cross (6) toggled by pin (8) and locked and guided by disk (7). Disk (7) and pin (8) are rigidly anchored to the case or frame or milled into the supporting plates (not shown).

The maltese cross revolves once in four years being toggled once every twelve months as it is carried by wheel (3). For the twenty eight day months the teeth on wheel (5) effectively fill in the tooth representing the 29th of February on wheel (3).

However every fourth year or leap year the missing tooth on wheel (5) moves into position over wheel (3) providing effictively only two teeth on wheel (3) and no tooth representing the twenty ninth of February. This permits wheel (3) & thus wheel (1) to move to day twenty nine of February without being toggled by wheel (11).

In Fig. 1 if wheel (3) is as depicted with only 2 teeth for February, the calender will work without needing to be reset even for the month of February during a leap year. It will manually have to be set for the 3 preceeding years only for the month change from February to March as it will move to the Twenty ninth day of February. If however wheel (3) had one more tooth representing the twenty ninth of February, the calendar would work as a three year calendar requiring to be set only once in the month of February only during the leap year.

The Perpetual Calendar mechanism is operated as follows: With respect to Figures 1 & 2, The wheels (1) & (3) are set to indicate the current date and month by advancing wheel (1) clockwise by as many turns as is necessary to get the proper month indicated and stopping the rotation when the required date is reached. The means to provide a setting mechanism is not shown. The means to display the date and month by hands, window, disk or dial are also not shown as these features are no essential to the understanding of the functioning of the present invention. The wheel (13) is made to mesh with the hour wheel of a clock or watch, such that it makes one revolution every twenty four hours. Alternately the wheel (12) could be the actual hour wheel of the clock or watch. This will make wheel (12) make one complete revolution in twelve hours. This is ideally suited to drive wheel (11) and a simple 1:2 drive ratio would need be maintained between wheel (12) and wheel (13).

The Mechanism does not require any other settings as long as the clock can supply the motive force to drive the mechanism and maintain accurate time.

Claims

Claim 1.

A Perpetual Calendar Mechanism comprising a date wheel (1) of thirty one divisions. The herein mentioned Date Wheel (1) is advanced by one division once every twenty four hours by a finger or pawl (14) mounted on day wheel (13). A sector gear (2) mounted co-axially with wheel (1), cooperates with wheel (4) such that wheel (4) makes one twelveth of one revolution for every one revolution made by wheel (1), in four distinct steps covering the sector representing the date transitions from 28-29, 29-30, 30-31, & 31-1 with reference to wheel (1). A forty eight division month wheel (3) mounted coaxially with wheel (4), with teeth representing the missing days of the respective short months, co-operates with a three tooth wheel (11) as and when the said teeth on wheel (3) move into meshing position with wheel (11). The wheel (3) being driven by as many divisions as there are teeth on the said wheel, in turn driving wheel (1) via sector gear (2) by the same number of divisions. A three tooth wheel (5) mounted coaxially with Maltese Cross (6) mounted on wheel (3), is activated once, by the a rigidly fixed finger (8) and guide (7), for every one revolution made by wheel (3). The teeth on Wheel (5) also cooperate with wheel (11) for for three quarters of one revolution of the said wheel (5), and does not cooperate with wheel (11) during the last quarter revolution of wheel (5).
Claim 2.

A Perpetual Calendar Mechanism as claimed in Claim 1, wherein the means of advancing the month wheel (3) by one twelveth of one revolution is provided bz a sector gear (2) cooperating with another wheel (4), when sector wheel (2) can drive or be driven by wheel (4) over the respective angles of cooperation of the two said wheels, as determined by the sector gear (2).
Claim 3.

A Perpetual Calendar Mechanism as claimed in Claim 1, and Claim 2, wherein the geared sector of sector wheel (2) is chosen to provide an arc of cooperation between sector wheel (2) and wheel (4), representing the equivalent of four of the thirty one divions of wheel (1) and one twelveth of a revolution of wheel (4).
Claim 4.

A Perpetual Calendar Mechanism as claimed in Claim 1, wherein a forty eight division wheel (3) also called the month wheel, is provided with a means to encode the number of days less than thirty one for all the twelve months of a Gregorian year. The means of encoding the shortfall in days of the short months also serving as a means of cooperating with another driving wheel (11).
Claim 5.

A Perpetual Calendar Mechanism as claimed in Claim 1 & Claim 4 wherein the means to indicate the shortfall in days of the short months by the presence of one or more teeth on wheel (3), and the said means serving to cooperate with wheel (11) substantially as described herein as component (3) with reference to figures 1 & 3 of the accompanying diagrams.
Claim 6.

A Perpetual Calendar Mechanism as claimed in Claim 1, Claim 4 & Claim 5, wherein a four division wheel (5) with only three teeth on three consecutive divisions or quarters and no tooth on the fourth quarter,mounted co-axially and driven by a Maltese Cross (6), and mounted on wheel (3), such that the teeth of the said wheel (5) can cooperate with wheel (11).
Claim 7.

A Perpetual Calendar Mechanism as substantially described herein with reference to Figures 1,2,3 & 4 of the accompanying diagrams.

Claim 7.

A Perpetual Calendar Mechanism as substantially described herein with reference to Figures 1,2,3 & 4 of the accompanying diagrams.

Amendments to the claims have been filed as follows Claim 1.

A Perpetual Calendar Mechanism comprising a date wheel (1) of thirty one divisions, the said Date Wheel (1) being advanced by one division once every twenty four hours by a finger or pawl (14) mounted on day wheel (13), and a sector gear (2) mounted co-axially with wheel (1) cooperates with wheel (4) such that wheel (4) makes one twelveth of one revolution for every one revolution made by wheel (1), in four distinct steps covering the sector representing the date transitions from 28-29, 29-30, 30-31, & 31-1 with reference to wheel (1), and a forty eight division month wheel (3) mounted co-axially with wheel (4) with teeth representing the missing days of the respective short months, co-operates with a three tooth wheel (11) as and when the said teeth on wheel (3) move into meshing position with wheel (11), the wheel (3) being driven by as many divisions as there are teeth on the said wheel, in turn driving wheel (1) via sector gear (2) by the same number of divisions, and a three tooth wheel (5) mounted co-axially with Maltese Cross (6) mounted on wheel (3) is activated once, by the a rigidly fixed finger (9) and guide (7), for every one revolution made by wheel (3), the teeth on Wheel (5) also cooperating with wheel (11) for for three quarters of one revolution of the said wheel (5), and not cooperating with wheel (11) during the last quarter revolution of wheel (5).

Claim 2.

A Perpetual Calendar Mechanism as claimed in Claim 1, wherein the means of advancing the month wheel (3) by one twelveth of one revolution is provided by a sector gear (2) cooperating with another wheel (4), wherein sector gear (2) can drive or be driven by wheel (4) over the respective angles of cooperation of the two said wheels, as determined by the sector gear (2).

Claim 3.

A Perpetual Calendar Mechanism as claimed in Claim 1, and Claim 2, wherein the geared sector of sector wheel (2) is chosen to provide an arc of cooperation between sector wheel (2) and wheel (4), representing the equivalent of four of the thirty one divions of wheel (1) and one twelveth of a revolution of wheel (4).

Claim 4.

A Perpetual Calendar Mechanism as claimed in Claim 1, wherein a forty eight division wheel (3) also called the month wheel, is provided with a means to encode the number of days less than thirty one for all the twelve months of a Gregorian year, *he means of encoding the shortfall in days of the short months also serving as a means of cooperating with another driving wheel (11).

Claim 5.

A Perpetual Calendar Mechanism as claimed in Claim 1 & Claim 4 wherein the means to indicate the shortfall in days of the short months by the presence of one or more teeth on wheel (3), and the said means serving to cooperate with wheel (11) substantially as described herein as component (3) with reference to figures 1 & 3 of the accompanying diagrams.

Claim 6.

A Perpetual Calendar Mechanism as claimed in Claim 1, Claim 4 & Claim 5, wherein a four division wheel (5) with only three teeth on three consecutive divisions or quarters and no tooth on the fourth quarter,mounted co-axially and driven by a Maltese Cross (6), and mounted on wheel (3), such that the teeth of the said wheel (5) can cooperate with wheel (11).