EP1351105B1 - Timepiece with perpetual calender display - Google Patents

Abstract

The display (43) consists of an indicator (46) which sweeps over concentric disks. An outer disk (47) shows days of the week for four weeks and two disks (51,52) show the day of the month for first and second parts of the month. The month is displayed on an inner disk (56). The first and second day of the month disks are successively displaced by amounts to allow for the month length and then restore correct order

Description

The present invention relates to a timepiece equipped with a clockwork movement and a calendar display comprising: a dial having a fixed graduation in days of whole weeks which extends over the entire circumference of the dial , date indicator means, driven in rotation in steps and having at least one date scale in correspondence with the graduation of the days, and a movable calendar index rotated by the watch movement against the graduations of the days and dates.

The patent FR884544 discloses a calendar watch for displaying with a single hand the day of the week and the date.

The patent application EP 285 881 describes a perpetual calendar electronic wristwatch of this kind, in which central hour, minute and second hands are driven by a first motor to indicate the time, a fourth central hand is driven from that motor to 1/35 of a turn per day to indicate the date, while another off-center hand is driven by a second motor to indicate the month. The date is indicated by the fourth hand on two concentric graduations, namely a fixed graduation of days which is divided into thirty-five equal sectors bearing the names of the days of five consecutive weeks, and a graduation of the dates carried by a rotating disk and divided equally into thirty-five equal sectors of which thirty-one consecutive fields bear the dates from 1 to 31, the other four sectors being virgin. At the end of each month, the date disc is moved by a third motor to place the next month's calendars in correspondence of the graduation of the days. Thus, the user can see at any time the complete calendar of the current month, while the fourth hand indicates the date and the day on the graduations matched. However, a disadvantage of this way of displaying the date is that, until the evening of the last day of the month, the user can not see the calendar of the beginning of the following month. On the other hand, in a watch having a mechanical clockwork movement, the design of a mechanism causing such a date display would be very difficult.

In the patent french no. 793,442 a mechanical calendar has been proposed in which the seven calendars of a whole week are visible in a window beside which are inscribed the names of the days of the week. The mechanism comprises two concentric date discs each having a semicircular sector which carries the dates of a first part or a second part of the month, the ends of these sectors overlapping over one, two or three days, alternatively to place the next month's date 1 after the last date of the previous month, then to restore the continuous continuation of the calendars around the middle of the month. The rotation of the two date discs is operated once a week by means of a manual control or a clockwork movement. The relative movements of one of these disks relative to the other are determined by a cam mechanism carried by one of the disks and representing the different lengths of the months.

This mechanical calendar has the disadvantage of not indicating the current date because it can not be combined with a rotary indicator such as a needle driven by a clockwork movement. The observer must therefore know a priori what is the day of the week to be able to read the date or vice versa. In addition, he can only read the calendar for one week at a time. Another disadvantage is that when the week extends to the end of a month and the beginning of the following month, the observer does not know whether the name of the month displayed in the window provided for this purpose corresponds to the beginning or the weekend.

A primary object of the present invention is to overcome the aforementioned drawbacks by a date display mode allowing a global view of the calendar not only on the current week, but also on one or more weeks to come, whatever the number of days in the current month. Preferably, the calendar will be of the perpetual type, that is to say taking into account leap years.

An additional object of the invention is to allow the indication of the date by means of a single moving index indicating not only the day and the date, but also the month and possibly the year.

Another object of the invention is to design a calendar mechanism capable of causing such a calendar display from the watch movement.

• en ce que les moyens indicateurs de quantièmes comportent deux disques de quantièmes concentriques susceptibles d'être décalés angulairement l'un par rapport à l'autre, à savoir un premier disque dont la graduation comporte les quantièmes d'une première partie d'un mois et un second disque dont la graduation comporte les autres quantièmes jusqu'à 31, correspondant à une seconde partie d'un mois,
• en ce que le premier disque de quantièmes est agencé pour être déplacé de N pas dans la seconde partie d'un mois, N étant égal au nombre de jours dudit mois moins le nombre de jours de la graduation des jours, de sorte que le dernier quantième dudit mois sur la graduation du second disque est suivi du premier quantième du mois suivant sur la graduation du premier disque,
• et en ce que le second disque de quantièmes est agencé pour être déplacé du même nombre N de pas dans la première partie du mois suivant, ce qui rétablit la suite continue des quantièmes sur l'ensemble formé par les deux graduations de quantièmes.

For this purpose, there is provided a timepiece of the type indicated above in the preamble, characterized:

• in that the date indicator means comprise two concentric date discs that can be angularly offset with respect to one another, namely a first disc whose graduation includes the dates of a first part of a month and a second disk whose graduation includes the other calendars up to 31, corresponding to a second part of a month,
• in that the first date disk is arranged to be moved N in the second part of a month, N being equal to the number of days of said month minus the number of days of the graduation of the days, so that the last date of said month on the graduation of the second disc is followed by the first calendar of the following month on the graduation of the first disc,
• and in that the second date disk is arranged to be moved by the same number N of steps in the first part of the following month, which restores the continuous sequence of the dates on the set formed by the two graduations of dates.

Thus, the calendar display always shows a correspondence between the calendars and the days over a period of several weeks that includes the current week and one or more weeks that follow, which helps the user to choose dates in this calendar. period, for example to schedule appointments. In the first part of the month, this period spans the entire month in progress. In the second part of the month, which can start at any date chosen by the manufacturer, preferably between 15 and 20, the first date disk is moved while the second disk remains stationary, so that the date of the month 1 next month takes place just after the last day of the current month. Consequently, the correspondence between dates and days is established not only for the end of the current month, but also for the first part of the following month.

Of course, the mobile calendar index is driven to move forward one day in 24 hours next to the fixed graduation of days. It indicates at the same time the day and the date on the respective graduations matched one of the other.

In a first particular embodiment, the graduation of the days comprises 28 days on the turn of the dial, so that N is always positive and that the movements of the date discs take place in the increasing direction of the graduations of the days and the calendars. . Thus, the calendar display always shows a correspondence between the calendars and the days over a period of four weeks. The mobile calendar index is driven in this case so as to take a turn in 28 days next to the fixed graduation of the days.

In a second particular embodiment, the graduation of the days comprises 35 days on the turn of the dial, so that N is always negative and that the movements of the date discs are made in the decreasing direction of the graduations of the days and the calendars. . Thus, the calendar display always shows a correspondence between the calendars and the days over a period of more than four weeks. The mobile calendar index is driven in this case so as to take a turn in 35 days next to the fixed graduation of the days.

In both of the aforementioned embodiments of the invention, the calendar display may be advantageously completed by a disc of the months, divided into twelve sectors, each bearing the name of a month and concentrically arranged with date discs, next to calendar mobile index, this record of the months being driven so as to perform, relative to the moving index, a relative rotation of a turn in one year. This relative rotation is preferably in the opposite direction to that of the rotation of the index, so that the increasing order of months is arranged in the same direction as the increasing order of days and dates.

The perpetual type calendar display may further include a year disk, preferably divided into four sectors corresponding to the four years of a leap year cycle, this disk being driven in continuous relative rotation with respect to the index of calendar so as to perform a four-year turn against this index.

• la figure 1 représente un premier mode de réalisation des organes d'affichage d'une montre à calendrier perpétuel selon l'invention, comprenant un affichage classique de l'heure et un affichage de calendrier, à la date du 31 janvier 2001,
• la figure 2 représente l'affichage de calendrier à la date du 5 février 2001,
• la figure 3 représente l'affichage de calendrier à la date du 19 février 2001,
• la figure 4 représente l'affichage de calendrier à la date du 5 mars 2001,
• la figure 5 représente l'affichage de calendrier à la date du 19 avril 2001,
• la figure 6 représente l'affichage de calendrier à la date du 5 mai 2001,
• la figure 7 représente l'affichage de calendrier à la date du 19 février 2004,
• la figure 8 représente l'affichage de calendrier à la date du 5 mars 2004,
• la figure 9 représente un deuxième mode de réalisation de l'affichage de calendrier, à la même date que dans la figure 5,
• la figure 10 représente l'affichage de calendrier de la figure 9 à la même date que dans la figure 6,
• la figure 11 représente un troisième mode de réalisation de l'affichage de calendrier, à la même date que dans la figure 3,
• la figure 12 représente schématiquement un mode de réalisation d'un mécanisme de calendrier perpétuel pour commander l'affichage de calendrier selon la figure 11,
• la figure 13 est un schéma en coupe du mécanisme de la figure 12,
• la figure 14 est une vue agrandie d'une roue de programme du mécanisme de la figure 12, dans une position correspondant au mois d'avril d'une année normale,
• la figure 15 est une vue en coupe suivant la ligne XV-XV de la figure 14,
• la figure 16 représente la roue de programme de la figure 14 dans une position correspondant à la fin de février d'une année bissextile,
• la figure 17 représente schématiquement un mode de réalisation d'un mécanisme de calendrier perpétuel pour commander l'affichage de calendrier selon les figures 1 à 8, et
• la figure 18 est un schéma en coupe du mécanisme de la figure 17.

Other characteristics and advantages of the present invention will become apparent in the following description of various embodiments, given by way of non-limiting example with reference to the accompanying drawings, in which:

• the figure 1 represents a first embodiment of the display devices of a perpetual calendar watch according to the invention, comprising a conventional display of the time and a calendar display, on January 31, 2001,
• the figure 2 represents the calendar view as of February 5, 2001,
• the figure 3 represents the calendar view as of February 19, 2001,
• the figure 4 represents the calendar display as of March 5, 2001,
• the figure 5 represents the calendar display as of April 19, 2001,
• the figure 6 represents the calendar display as of May 5, 2001,
• the figure 7 represents the calendar view as of February 19, 2004,
• the figure 8 represents the calendar view as of March 5, 2004,
• the figure 9 represents a second embodiment of the calendar display, on the same date as in the figure 5 ,
• the figure 10 represents the calendar display of the figure 9 on the same date as in the figure 6 ,
• the figure 11 represents a third embodiment of the calendar display, on the same date as in the figure 3 ,
• the figure 12 schematically represents an embodiment of a perpetual calendar mechanism for controlling the calendar display according to the figure 11 ,
• the figure 13 is a sectional diagram of the mechanism of the figure 12 ,
• the figure 14 is an enlarged view of a program wheel from the mechanism of the figure 12 in a position corresponding to the month of April of a normal year,
• the figure 15 is a sectional view along line XV-XV of the figure 14 ,
• the figure 16 represents the program wheel of the figure 14 in a position corresponding to the end of February of a leap year,
• the figure 17 schematically represents an embodiment of a perpetual calendar mechanism for controlling the calendar display according to the Figures 1 to 8 , and
• the figure 18 is a sectional diagram of the mechanism of the figure 17 .

With reference to the figure 1 , the display members of the watch comprise conventional analog time indication members, comprising a hour hand 41 and a minute hand 42 which turn in front of a dial 43 bearing for example twelve fixed hourly markers 44. needles 41 and 42 are conventionally driven by a clockwork movement to rotate about the central axis 45 of the watch. Of course, we could still add a second hand in the center.

A calendar index 46 is driven by the watch movement of the watch so as to perform a complete revolution around the axis 45 in 28 days, preferably clockwise, with respect to a graduation of the days 47 which is fixed on the dial 43. The graduation 47, which extends over the entire round of the dial, is divided into twenty-eight equal sectors bearing the names of the days of four consecutive weeks. The index 46 is carried by an annular disc 48 which can be driven either continuously or by 1/28 turn to place the index 46 always in front of the middle of a sector of the fixed graduation 47. One could also provide a central hand to fulfill the function of the index 46, as will be seen later about the third embodiment.

The calendars 1 to 31 are distributed on respective sectors of two date discs 51 and 52, next to the graduation of the days 47. Each sector carrying a date extends over 1/28 of a turn, so that it can to be placed in exact correspondence of a sector of the graduation of days 47. The first date disc 51 carries a graduation 53 having the dates of a first part of the month, for example in this case the dates of 1 to 15 on fifteen consecutive sectors. The second date disc 52 carries a graduation 54 comprising the calendars of the second part of the month, that is to say in the present case from 16 to 31 out of sixteen consecutive sectors. The second disc 52 is located behind the first disc 51 and has a larger diameter, so that its graduation 54, disposed on a circular arc of greater radius than the graduation 53, is always visible along the periphery of the first 51 and that three sectors of the respective ends of the two graduations 53 and 54 can be juxtaposed, as seen in FIG. figure 1 for the dates 13 to 18.

Naturally, the index 46 facing one of the sectors of the graduation 47, bearing the name of the present day, indicates at the same time the date corresponding to this sector. If the index was in a zone where the two graduations 53 and 54 overlap (a circumstance which does not occur in the examples described here), the observer should by convention read the nearest date of the index, c that is to say on the first graduation 53.

Inside the disk 48 carrying the index finger 46, the perpetual calendar display comprises an annular disk of the months 56, bearing a graduation of the months 57 composed of twelve sectors whose respective angles are proportional to the length of the months that they represent. The disk 56 is driven by the clockwork movement so as to follow the disk 48 and its index finger 46, but with relative retrograde rotation to delay one revolution per year. Inside the disc 56 is an annular disc of the years 58 bearing a graduation 59 composed of four equal sectors, corresponding to the Julian cycle of four years, the last of which is leap and indicated by the Roman numeral IV. As a result, the 58-year-old disc is driven by the watch movement so as to follow the disc 48 carrying the index finger 46, but with relative retrograde rotation to delay by one revolution in four years relative to the disc 48. Thus, the index 46 analogically indicates the current month on the graduation 57 and the number of the year in the quadrennial cycle on the graduation 59, besides the day of the week and the date.

The relative rotations of the disks 56 and 58 with respect to the disk 48 of the index are retrograde because their graduations are increasing clockwise, which is that of the rotation of the index. Otherwise, if these relative rotations were in the same direction as the rotation of the disc 48, said graduations should be increasing in the opposite direction to that of the rotation of the disc 48. This would result in other ratios between the rotational speeds of these discs. .

In the figure 1 , the date displayed is Wednesday, January 31, 2001, which is the first year of a quadrennial cycle. We can read the correspondence between the calendars and the days of the week throughout the period from January 16th to February 15th of this year, that is to say on the second part of January and the first part of February. The limits of this period are highlighted by the overlap of the two date scales between 13 and 18.

At a predetermined date during the first part of the following month, namely in February, the second date disc 52 is advanced in one go by three steps of 1/28 of a turn (N = 3) in the increasing direction of its graduation. , that is, here clockwise, to the position represented in figure 2 . Its date 16 is then in the wake of the date 15 of the first disc 51. Thus, the display shows the correspondence between the days and the calendars over the entire month now in progress (February). The user notices this because the two date scales succeed one another in the middle of the month. In this example, said predetermined date is the 5th of each month, but the manufacturer may choose another date if he deems it appropriate.

We also notice in the figure 2 that the disc of the months 56 followed the rotation of the index 46, but with a small retrograde offset so that the index is now in front of the beginning of the sector "FEV" of the graduation of the months. In the same way, the record of the years 58 followed the rotation of the index 46, but with a small retrograde shift making that the index is now a little further in the sector "I" of the graduation of the years.

At a predetermined date during the second part of the current month (February), the first date disc 51 is advanced from zero steps, that is to say does not move, because for February of a normal year N = 28 days - 28 = 0. The figure 3 for example, represents the state of the calendar display on February 19, 2001. The date of the 19 is chosen here for moving the first disk because it is the first that avoids the presence of the index 46 in front of the zone of overlap of the two date scales, for example in their position represented in figure 1 .

At a predetermined date during the first part of the following month, namely on March 5, 2001, the second date disc 52 is advanced by the same number of steps N = 0 as in the previous operation, that is to say that it does not move and that the state of the display on that date is represented by the figure 4 .

On March 19, the first date disc 51 is advanced N = 31 - 28 = 3 steps to bring its date 1 after the 31st of March. This state is not represented. The correspondence between days and dates is then established for the second part of March and the first part of April.

On April 5, the second date disc 52 is advanced by the same number of steps N = 3 as in the previous operation, in order to reset its date 16 after the date of the first disc 51 and thus display the correspondence between days and calendars throughout the month of April. This state is not represented.

On April 19, the first date disc 51 is advanced by N = 30-28 = 2 steps to bring its date 1 after the April 30th date, in the position shown in FIG. figure 5 . Correspondence between days and dates is then established for the second part of April and the first part of May.

On May 5th, the second date disc 52 is advanced by the same number of steps N = 2 as in the previous operation, in order to put its date 16 back to the following the date 15 of the first disc 51 and thus display the correspondence between days and calendars throughout the month of May. This state is represented in figure 6 . The same pair of operations is carried out during the successive months, with the appropriate values of N.

The Figures 7 and 8 show the transition from February to March in a leap year. On 19 February 2004 corresponding to the figure 7 , the first date disc 51 has been advanced by N = 29 - 28 = 1 step to bring its date 1 after the last 29th of February. Correspondence between days and dates is then established for the second part of February and the first part of March.

On 5 March 2004 corresponding to the figure 8 , the second date disc 52 has been advanced by the same number of steps N = 1 as in the previous operation, in order to reset its date 16 after the date of the first disc 51 and thus display the correspondence between days and calendars. throughout the month of March.

In a variant not shown, the part of the first disc 51 which is not covered by the graduation 53 could be removed and the portion bearing this graduation could cover the edge of the second disc 52, so that the two graduations 53 and 54 could be arranged on arcs of equal radius and that the ends of the first graduation 53 could be superimposed on those of the second graduation 54 instead of being juxtaposed. This would have the advantage of reducing the radial clutter of the display, but would prevent reading the calendar over a period of more than 28 days.

The Figures 9 and 10 show a second embodiment which avoids this last disadvantage. Only here will be described what differs from the first embodiment. Of course, the watch also includes the time display members 41 to 44 shown in FIG. figure 1 but these are omitted in the Figures 9 and 10 to clarify the drawing. The fixed graduation 47 days is divided in this case into thirty-five equal sectors and thus covers five weeks. The calendar index 46 is driven in the increasing direction of the graduation 47, in this case clockwise, so as to take a turn in 35 days. On the first date disk 51, the edge zone carrying the graduation 53 covers the second date disk 52 and is indented on the rest of the circumference to show the graduation 54 of the second disc, except that it will hide the dates 29, 30 and / or 31 at the end of the months of less than thirty-one days thanks to the relative movements of the disks 51 and 52.

The figure 9 represents the state of the calendar display on Thursday, April 19, 2001, so on the same date as in the figure 5 . Previously the position of the first disk 51 was such that its date 15 was next to the date 16, the two graduations 53 and 54 thus being connected to display the complete calendar of the month of February. To reach the position of the figure 9 , the first disk 51 has retracted N = 5 steps relative to the fixed graduation 47 and the second disk 52, so in the counterclockwise direction, to place its date 1 now representing May 1 following the calendar 30 representing on April 30, the sector of the date of 1 covering that of 31. The display thus shows the correspondence between days and calendars for the second part of April and the first part of May. In this embodiment, the absolute value of the number N is equal to minus the number of days in the current month.

In the first part of the next month, here on May 5, 2001, the calendar display is put in the position represented in figure 10 by a decline of the same number of five steps of the second disc 52 to bring the date 16 after the 15 and then show the correspondence between days and calendars throughout the month of May. We also see in this figure that in the second part of May, the first disc 51 will have to move back four steps to place its date 1 after 31, June 1, 2001 being a Friday.

Note further that the fixed graduation of days 47 could be arranged outside with respect to the date scale 53 and 54, without the readability of the display is affected.

où S est le nombre de semaines de la graduation des jours et M est le nombre de jours du mois concerné. Une valeur positive de N caractérise une rotation du disque dans le sens croissant des graduations des jours et des quantièmes. Par exemple, dans le deuxième mode de réalisation décrit ci-dessus, S vaut 5 et la formule devient N = M - 35, de sorte que N est toujours négatif et que les disques doivent donc reculer par rapport à la graduation des jours.While the two embodiments described above are based on a graduation of days covering respectively four weeks and five weeks on the circumference of the dial, we can predict a number of different weeks and generalize the concept of the display by both date discs 51 and 52 moved alternately by N steps, defining an algebraic value (positive or negative) of N by the following formula: $$\mathrm{NOT}\mathrm{=}\mathrm{M}\mathrm{-}\mathrm{7}\mathrm{\cdot }\mathrm{S}$$

where S is the number of weeks of the graduation of the days and M is the number of days of the month concerned. A positive value of N characterizes a rotation of the disc in the increasing direction of the graduations of the days and the calendars. For example, in the second embodiment described above, S is 5 and the formula becomes N = M-35, so that N is always negative and therefore the disks must move backward relative to the graduation of the days.

It should be noted, however, that a value of S less than 4 makes it difficult to read the dates, because of the size of the recoveries of their two. graduations, and that a value of S greater than 5 requires very small inscriptions and has no advantage. This is why embodiments where S is 4 or 5 are preferable.

The Figures 11 to 13 illustrate a third embodiment, which is close to the first and which will be described essentially differences with respect to the latter.

A first difference is that the index 46 and the disc 48 carrying it in the first embodiment are replaced by a central hand which constitutes the calendar index 46. It also makes a turn in 28 days in the increasing direction of the graduation of the days 47. To be well distinguished from the hands of the hours 41 and minutes 42, the hand of the calendar index 46 may for example have a particular color.

A second difference is that the fixed graduation of days 47 is arranged around the annular date disks 51 and 52, that is to say directly on the dial of the watch. This avoids interposing a fixed element between the different disks of the calendar mechanism.

Finally, a third difference lies in the display of years. In this embodiment, the annular disk of the years 58 performs a revolution in ten years with respect to the index 46, its graduation 59 bearing the numbers of 0 to 9. In addition, a central disc of the decades 60 is arranged concentrically at center of the calendar display and carries an index of decades 61 next to the graduation of the 59s. The record of decades is driven so as to perform a lap in a hundred years compared to the record of the 58 years. index 61 indicates on the graduation 59 the number of tens of the current year. This can be recalled to the user by means of an inscription such as "x 10" on the index of decades 61.

The calendar display members of the examples described above may be actuated by any appropriate means, at times determined by the mechanical, electromechanical or electronic movement of any timepiece, be it a watch or a clock. They can in particular be operated by one or more electric motors dedicated to them.

The figures 12 and 13 represent a calendar mechanism capable of operating the display represented in the figure 11 from the watch movement of the analog watch, more precisely from a central wheel hours 99 which is integral with the hour hand 42 and which obviously takes a turn in twelve hours. In the figure 13 , the numbers written in italics represent the numbers of mobile teeth that will be described below.

The hour wheel 99 meshes with a wheel 101 having a pinion 102 which meshes with a wheel 103 having a pinion 104, which meshes with a wheel 105 integral with two other wheels 106 and 107. The wheel 105 s meshes with a wheel 108 fixed on a barrel 109 which surrounds the axes of the needles 41, 42 and which carries the calendar index needle 46. With the numbers of teeth indicated in FIG. figure 13 , it is verified that the transmission ratio between the hour wheel 99 and the index 46 is: $${\mathrm{R}}_{\mathrm{i}}\mathrm{=}\frac{\mathrm{15}\mathrm{\cdot }\mathrm{8}\mathrm{\cdot }\mathrm{18}\mathrm{\cdot }\mathrm{29}}{\mathrm{45}\mathrm{\cdot }\mathrm{64}\mathrm{\cdot }\mathrm{29}\mathrm{\cdot }\mathrm{42}}\mathrm{=}\frac{\mathrm{1}}{\mathrm{56}}$$

As the 99 hour wheel rotates two times a day, the index finger 46 rotates clockwise in exactly 28 days.

The wheel 107 meshes with a central wheel 110 secured to the disk of the years 58. In order to follow the index 46 by delaying with respect to it a lap in ten average years of the Julian cycle, the disk 58 is driven by the wheel 99 with the following transmission ratio: $${\mathrm{R}}_{\mathrm{at}}\mathrm{=}\frac{\mathrm{15}\mathrm{\cdot }\mathrm{8}\mathrm{\cdot }\mathrm{18}\mathrm{\cdot }\mathrm{37}}{\mathrm{45}\mathrm{\cdot }\mathrm{64}\mathrm{\cdot }\mathrm{29}\mathrm{\cdot }\mathrm{54}}\mathrm{=}\frac{\mathrm{37}}{\mathrm{2088}}\mathrm{=}\frac{\mathrm{1}}{\mathrm{56}\mathrm{,}\mathrm{432432}}$$

As a result, the year 58 disc rotates clockwise a little more slowly than the index 46, with respect to which it undergoes the following shift (expressed in number of revolutions) during an average year of the Julian cycle: $${\mathrm{D}}_{\mathrm{at}}\mathrm{=}\left(\frac{\mathrm{1}}{\mathrm{56}\mathrm{,}\mathrm{432432}}\mathrm{-}\frac{\mathrm{1}}{\mathrm{56}}\right)\mathrm{\cdot }\mathrm{2}\mathrm{\cdot }\mathrm{365}\mathrm{,}\mathrm{25}\mathrm{\cong }\mathrm{-}\frac{\mathrm{1}}{\mathrm{10}}\mathrm{t}\mathrm{/}\mathrm{year}$$

The wheel 106 meshes with a wheel 111 secured to the disc of the 60s. The latter is driven by the hour wheel 99 with the following ratio: $${\mathrm{R}}_{\mathrm{d}}\mathrm{=}\frac{\mathrm{15}\mathrm{\cdot }\mathrm{8}\mathrm{\cdot }\mathrm{18}\mathrm{\cdot }\mathrm{24}}{\mathrm{45}\mathrm{\cdot }\mathrm{64}\mathrm{\cdot }\mathrm{29}\mathrm{\cdot }\mathrm{35}}\mathrm{=}\frac{\mathrm{1}}{\mathrm{56}\mathrm{,}388889}$$

Thus, we note that the record of the decades turns clockwise less quickly than the index 46, but slightly faster than the record of the 58 years. In an average year, it undergoes the following shift with respect to the disk 58: $${\mathrm{D}}_{\mathrm{d}}\mathrm{=}\left(\frac{\mathrm{1}}{\mathrm{56}\mathrm{,}388889}\mathrm{-}\frac{\mathrm{1}}{\mathrm{56},432432}\right)\mathrm{\cdot }\mathrm{2}\mathrm{\cdot }\mathrm{365}\mathrm{,}\mathrm{25}\mathrm{\cong }+\frac{\mathrm{1}}{\mathrm{100}}\mathrm{t}\mathrm{/}\mathrm{year}$$

In this way, the index of decades 61 takes a hundred years to go through the entire graduation of the 59s and indicates the decade on this graduation.

On the barrel 109 is fixed a driving wheel 112 which meshes with a wheel 113 integral with a wheel 114, which meshes with a central wheel 115 secured to the disc of the month 56. This disc is driven by the barrel 109 of index 46 clockwise such that its offset from index 46 in an average year is: $${\mathrm{R}}_{\mathrm{m}}\mathrm{=}\left(\frac{67\cdot 16}{27\cdot 43}\mathrm{-}1\right)\mathrm{\cdot }\frac{\mathrm{365}\mathrm{,}\mathrm{25}}{28}\mathrm{\cong }\mathrm{-}1\mathrm{t}\mathrm{/}\mathrm{year}$$

On the other hand, the driving wheel 112 drives the date discs 51 and 52 by means of a perpetual calendar mechanism 120 shown in the right part of the drawings. figures 12 and 13 . The wheel 112 meshes with a wheel 121 integral with a wheel 122 which meshes with a wheel 123, itself secured to a wheel 124 to a tooth 125. The wheels 123 and 124 are driven by the barrel 109 at the rate of 12 rounds clockwise per average year, which is apparent from the following formula in which R _i is given by formula (1): $$2\cdot {\mathrm{R}}_{\mathrm{i}}\mathrm{\cdot }\frac{67\cdot 12}{46\cdot 19}\mathrm{\cdot }\mathrm{365}\mathrm{,}\mathrm{25}\mathrm{\cong }12\mathrm{t}\mathrm{/}\mathrm{year}$$

Two program wheels 126 and 127 are arranged on either side of the wheel 124, so that the single tooth 125 of the latter alternately drives the two program wheels counterclockwise, each once a month with a shift of half a month between one and the other. Note that this offset can be changed by slightly moving the wheel to a tooth relative to the program wheel pair. Each program wheel 126 and 127, the structure of which will be described later, takes one complete turn per calendar year, regardless of the number of days this year.

The first program wheel 126 stepping a pinion 130 integral with a wheel 131 which meshes with an internal toothing 132 of the first date disk 51. The second program wheel 127 drives step by step a pinion 134 integral with a wheel 135 which meshes with an internal toothing 136 of the second date disk 52. In the figure 13 the second program wheel 127 is omitted to clarify the drawing.

Table I shows more precisely the number of revolutions made by the main rotary mobiles of the calendar mechanism represented in FIG. figure 13 , in an average year of the Julian cycle. Table I Reference number Designation Number of laps in 365.25 days 99 Hour wheel 730.5 46 Calendar Index 13.04464 56 Disc of the months 12.04467 58 Record of the years 12.94468 60 Record of decades 12.95468 124 One-tooth wheel 11.99988

The value indicated in the last line of Table I has a relative error of -10 ^-6 compared to the ideal value of 12, so that the moment when the one-tooth wheel 124 controls the advance of a date disc will be around 5 minutes a year, which is better than the accuracy of a good mechanical watch.

Note that if the timing mechanism were to be driven not by the watch movement, but by a clean electric motor, the wheels 101 to 104 could be removed and the motor could be controlled by the watch movement to drive once per day the mobile formed wheels 105 to 107.

The figures 14 and 16 represent the program wheel 126 in two situations which correspond respectively to the month of April of a normal year (to reach the state of the display according to the figure 5 ) and at the end of February of a leap year (display status according to the figure 7 ).

The program wheel 126 is a composite wheel that rotates on a fixed axis 139 provided with a fixed wheel 140 with six teeth. It comprises a first board 141 provided with an input toothing with twenty-four teeth 142 regularly spaced, a second board 143 provided with an output toothing 144 which will be described later, two eight-toothed planet wheels 145 and 146 which meshes with the fixed wheel 140, and a sliding movable member 147 provided with a single tooth 148 preceded by a hollow 149 itself preceded by a shoulder 150 in an arc. The elements 140, 145, 146 and 147, which are drawn in bold lines to facilitate the reading of the drawing, are housed between the boards 141 and 143, in a recess 152 of the second board 143. The side wall of this recess presents two shoulders 153 and 154 forming stops which define the two functional positions of the sliding element 147. The planet wheels 145 and 146 are rotatable about respective pins 155 and 156 secured to the second board 143. With the fixed wheel 140, they constitute a control mechanism of the sliding element 147, as will be described later.

The exit gear 144 of the program wheel is a toothing with thirty-six modules, but has only twenty-four teeth 158 and twenty-nine recesses 159 adjacent to these teeth, the teeth and the recesses being arranged in groups which are separated by five gaps corresponding to months of less than 31 days. These gaps are occupied by respective shoulders 160 to 164 in an arc, respectively corresponding to the months of February, April, June, September and November. The shoulders 161 to 164 correspond to the removal of two teeth and a hollow between them, for the months of 30 days, while the shoulder 160 corresponds to the removal of three teeth and two recesses therebetween, for a month of February of 29 days. In the position shown in figure 14 , the shoulder 150 of the sliding element 147 extends the shoulder 160 of a module, so that these two shoulders combined correspond to the removal of four teeth and three recesses therebetween for a normal February of 28 days.

The height of the shoulders 150 and 160 to 164, that is to say their radius relative to the center 151 of the program wheel, is sufficient so that two successive teeth of the pinion 130 can slide while leaning against the shoulder , thus blocking the position of the pinion 130, of the wheel 131 ( figure 12 ) and the date disk 51 associated with the latter. Thus, the successive positions of the date disk are indexed by the output teeth of the program wheel, without the need for a jumper spring. Indexing of this kind and its advantages are described in the patent Swiss no. 688,671 from the same applicant.

It will be understood that the passage of each shoulder 160 to 164 in front of the pinion 130 rotates it one step, so finally has the same effect as the passage of one of the teeth 158.

Each revolution of the wheel 124 with a tooth 125 produces a two-step advance of the entry gear 142 of the program wheel, that is to say a twelfth of a turn. Between these operations in advance, the program wheel is stopped by the circular periphery 176 of the wheel 124, which is supported by sliding against the head of the teeth 142. The program wheel, thus driven twelve times a year, makes a full tour per year. In the figures 14 and 16 , the circumference of the program wheel is subdivided into twelve sectors equal to 30 degrees, numbered by the Roman numerals I to XII and corresponding to the twelve months of the year. The number of troughs 159 associated with each month determines the number of steps of the advance made this month by the pinion 130, the wheel 131 and the date disc 51. This number is 0, 1, 2 or 3 depending on whether the month corresponds to twenty-eight, twenty-nine, thirty or thirty-one days, as explained above.

The sliding element 147 and its control mechanism are intended to change the number of steps of the advance corresponding to the month of February, depending on whether this month is twenty-eight or twenty-nine days. In the position shown in figure 14 , which corresponds to a month of February of 28 days, the element 147 is in the retracted position and its additional tooth 148 is superimposed on a tooth 158a of the second board 143. The thickness of the tooth 158a corresponds to half The two teeth 148 and 158a having exactly the same shape, the additional tooth 148 is somehow retracted and has no particular effect. The hollow 149 which precedes it is opposite a wider recess 166 of the board 143, which is otherwise covered by the shoulder 150 of the element 147. Thus, the pinion 130 will remain blocked by sliding on the shoulders 160 and 150 during the twelfth of a turn corresponding to the month of February of a normal year, and no step in advance of the date disc will be made, as described with reference to the figure 3 .

In the leap position represented in figure 16 , which corresponds to a month of February of 29 days, the sliding element 147 is moved temporarily to the left with respect to the preceding figure, so that its additional tooth 148 is moved one module relative to the toothing 144, while the adjacent hollow 149 of the sliding element is always facing the wider hollow 166 of the toothing 144. The shoulder 150 of the element 147 is then superimposed on the shoulder 160 of the board 143. The tooth 148 and the hollow 149 thus determine the unique pitch of the advance of the first date disk at the end of February of a leap year, as described with reference to the figure 7 .

The teeth of the two planet wheels 145 and 146 are arranged to abut by sliding against two corresponding edges 168 and 169 of the sliding element 147 in order to position this element, namely to move it between its two positions represented by figures 14 and 16 and position it positively continuously without the help of a spring. Since the gear ratio between the fixed wheel 140 and each of the planet wheels 145 and 146 is 3/4, each satellite wheel rotates three quarters of a year in the direction of the arrow that it carries. In other words, from February to the next, it is shifted a quarter of a turn in the opposite direction to the arrow. The wheel 145 has a long tooth 171 and seven short teeth 172, so that its long tooth 171 will push the sliding member 147 in February only one year out of four, which will put the element 147 in the leap position shown in FIG. figure 16 . On the other side, the satellite wheel 146 has five long teeth 173 that support each other. against the edge 169 of the element 147 to hold it in the position of the figure 14 , while the short teeth 172 of the other satellite wheel 145 pass along the opposite edge 168 of this element. The latter is retained by abutment against the shoulder 153. In the position of the figure 16 it is the three short teeth 174 of the wheel 146 which pass freely along the edge 169 of the element 147, which is retained by abutment against the shoulder 154. Furthermore, the element 147 has a curved inner edge 170 who can lean against the head of the teeth of the fixed wheel 140.

Between two successive leap years, the rotation of the planet wheels 145 and 146 will twice temporarily put the sliding element 147 in its leap position, but these events will occur at other months than February, so that the additional tooth 148 will be remote from pinion 130 and will have no effect at these times.

The second program wheel 127 is identical to the first one 126 and operates in exactly the same way, to drive the second date disk 52 with the same number of steps as the first, but with a half-month lag. If necessary, another value of this offset can be chosen by modifying the mutual positions of the axes of the program wheels and the wheel 124 which drives them.

The figures 17 and 18 are similar to figures 12 and 13 and represent a calendar mechanism capable of operating the display shown in Figures 1 to 8 from the watch movement of the analog watch, more precisely from a central wheel of the hours 99. In the figure 18 , the numbers written in italics represent the numbers of mobile teeth that will be described below.

The hour wheel 99 meshes with a wheel 171 having a pinion 172 which meshes with a central wheel 173 integral with the disc 48 carrying the calendar index 46. With the numbers of teeth indicated in the figure 18 , it is verified that the transmission ratio between the hour wheel 99 and the index 46 is: $${\mathrm{R}}_{\mathrm{i}}\mathrm{=}\frac{15\cdot 6}{60\cdot 84}=\frac{\mathrm{1}}{56}$$

As the 99 hour wheel rotates two times a day, the index finger 46 rotates clockwise in exactly 28 days.

The wheel 173, which is represented twice in the figure 18 to clarify the diagram, is integral with another central wheel 174 which meshes with a return formed of two wheels 175 and 176. The wheel 176 meshes with a central wheel 177 integral with the disc of the months 56 and a other central wheel 178. The latter involves, via a two-wheel return 180 and 181, a central wheel 182 secured to the disk of the years 58.

In addition, the central wheel 174 to sixty-seven teeth plays the same role of driving wheel that the wheel 112 of the example of figures 12 and 13 , to drive in the same way the date discs 51 and 52 via the perpetual calendar mechanism 120 comprising in particular the two program wheels 126 and 127, this mechanism being identical to that of the example mentioned above.

The foregoing description shows that the program wheels 126 and 127 of the perpetual calendar mechanism may have a relatively simple construction of small thickness. In addition, as the numbers of teeth of the elements that make it up are relatively small, the modules of the teeth are sufficiently large, which contributes to reducing the cost of manufacture. On the other hand, it should be noted that the entire calendar device described above is devoid of return springs or jumper springs, which have the disadvantage of creating friction, therefore wear and an adverse influence. on the watch.

In the second embodiment illustrated by the Figures 9 and 10 , where the number of steps N = M - 35 of the monthly displacements of each date disc are between 4 and 7 in absolute value, a person skilled in the art can construct a program wheel similar to the wheel 126 described above, but whose number of teeth and troughs in the output teeth 144 will be adapted to the values of N. This set of teeth must have up to 7 tooth modules per monthly sector (sectors I to XII represented in FIG. figure 14 ), so have a circumference divided into 84 modules.

Claims (16)

1. A timepiece provided with a clockwork movement and a calendar display comprising:

   a dial (43) provided with a fixed graduation (47) in days of several full weeks which extends over the entire circumference of the dial,

   means indicating dates (51, 52), driven in rotation by pitch and having at least one date graduation corresponding to the days graduation,

   and a mobile calendar index (46) driven in rotation by the clockwork movement across from the graduations of days and dates,

   characterized in that the means indicating dates comprise two concentric date discs (51, 52) able to be angularly offset relative to each other, namely a first disc (51) whereof the graduation (53) comprises the dates (1 to 15) of a first part of a month and a second disc (52) whereof the graduation (54) comprises the other dates up to 31, corresponding to a second part of a month,

   in that the first dates disc (51) is arranged to be moved by N pitches in the second part of a month, N being equal to the number of days of said month minus the number of days of the days graduation, such that the last date of said month on the graduation of the second disc is followed by the first date of the following month on the graduation of the first disc,

   and in that the second dates disc (52) is arranged to be moved by the same number N of pitches in the first part of the following month, which reestablishes the ongoing continuation of the dates on the assembly formed by the two dates graduations.
2. The timepiece according to claim 1, characterized in that the days graduation (47) comprises twenty-eight days around the circumference of the dial, such that N is always greater than or equal to zero and the movements of the date discs is done in the increasing direction of the day and date graduations.
3. The timepiece according to claim 1, characterized in that the day graduation (47) comprises thirty-five days on the circumference of the dial, such that N is always negative and the movements of the date discs are done in the decreasing direction of the day and date graduations.
4. The timepiece according to claim 1, characterized in that the calendar display comprises a month disc (56), concentric to the date discs and bearing a circular month graduation (57), this month disc being driven so as to complete one rotation relative to a revolution in a year relative to the mobile calendar index (46).
5. The timepiece according to claim 1, characterized in that the calendar display comprises a year disc (58), concentric to the date discs and bearing a circular year graduation (59), this year disc being driven so as to complete one revolution in a whole number of years relative to the mobile calendar index (46).
6. The timepiece according to claim 5, characterized in that the year disc (58) completes one revolution in ten years relative to said index, its graduation (59) bearing the figures from 0 to 9, and in that the calendar display also comprises a decade disc (60), driven so as to complete one revolution in one hundred years relative to said index and bearing a decade index (61) across from the year graduation (59).
7. The timepiece according to one of claims 1 to 6, characterized in that the two date graduations (53, 54) are arranged on circle arcs with different radiuses, such that they can be partially juxtaposed.
8. The timepiece according to one of claims 1 to 6, characterized in that the two date graduations (53, 54) are arranged on circle arcs with equal radiuses, such that they can be partially superimposed.
9. The timepiece according to one of claims 1 to 6, characterized in that it comprises a calendar mechanism (120) driven by the timepiece movement and having, in order to drive the first date disc (51), a first program wheel (126), driven one time per month by the timepiece movement so as to complete one revolution per year and provided with an exit toothing (144) having five gaps which correspond to the months having fewer than thirty-one days, and a train (130, 131) connecting the exit toothing of this program wheel to a toothing (132) of the first date disc (51).
10. The timepiece according to claim 9, characterized in that the calendar mechanism (120) comprises, to drive the second date disc (52), a second program wheel (127), similar to the first and driven once per month by the timepiece movement so as to complete one revolution per year, and a train (134, 135) connecting the exit toothing of the second program wheel to a toothing (136) of the second date disc (52), and in that the two program wheels (126, 127) are driven by a wheel (124) with one tooth (125) which completes twelve revolutions per year, the two program wheels being arranged on both sides of the single-toothed wheel in order to be driven by said tooth (125) alternatively in the first part and in the second part of each month.
11. The timepiece according to claim 9 or 10, characterized in that the or each program wheel (126, 127) bears a mobile element (147) provided with an additional tooth (148) and a control mechanism (140, 145, 146), the mobile element having a bissextile position, wherein the additional tooth (148) is added to the exit toothing (144) in the gap corresponding to the month of February, and a withdrawn position in which the additional tooth (148) is retracted, the control mechanism being arranged to put the mobile element (147) temporarily in the bissextile position in each month of February in positions of the program wheel which are offset by a quarter revolution from one year to the next, such that the additional tooth (148) drives the corresponding train only one out of every four years.
12. The timepiece according to claim 11, characterized in that said control mechanism comprises two planetary wheels (145, 146), mounted in rotation on the program wheel and meshing on a fixed wheel (140) concentric to the program wheel such that each planetary wheel is offset by a quarter revolution per year relative to the program wheel, these planetary wheels having cam surfaces which abut against said mobile element (147) to position it.
13. The timepiece according to claim 12, characterized in that the fixed wheel (140) has six teeth and each planetary wheel (145, 146) has eight teeth.
14. The timepiece according to claim 12, characterized in that said mobile element (147) is arranged to pivot around the center of the program wheel and in that its additional tooth (148), in its withdrawn position, is superimposed on one (158a) of the teeth of the exit toothing (144) of the program wheel.
15. The timepiece according to claim 10, characterized in that each program wheel (126, 127) has no springs.
16. The timepiece according to claim 10, characterized in that the calendar mechanism has no springs.

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