EP3270236A1 - Running time equation mechanism controlled by a differential device - Google Patents

Abstract

A walking time equation mechanism includes a switch whose function is to indicate the calendar time by means of an hour hand (46) and a minute hand (48), and a needle minutes of the true time (50), concentric with the minute hand of the civil time (48), and which indicates the minute of the true time, the equation mechanism of the walking time (44) also including an equation cam time (54) having a profile which is determined by the difference, for each day of the year, between the mean solar time or civil time, and the solar time or true time, that time equation cam (54) being rotated at a rate of one revolution per year by a date mechanism, the daily position of the minute hand of the true time (50) being determined by the position of the time equation cam (54), the walking time equation mechanism (44) also comprising a device differential gearing (64) whose first input is constituted by a roadway (72) secured to a civil time minute gun (70) on which is driven a minute hand of the civil time (48), and a second input is constituted by the time equation cam (54), the differential gear device (64) comprising a reducing satellite gear (74) via which the civil time minute gun (70) drives a gun of the hours of the civil time (84) on which is driven the hour hand of the civil time (46), and a multiplier satellite mobile (90) via which the canon of the hours of the civil time (84) causes a canon of the minutes of the true time ( 102) on which the minute hand of the true time (50) is driven.

Description

Technical field of the invention

The present invention relates to a walking time equation mechanism for a timepiece. More specifically, the invention relates to a walking time equation mechanism driving a minute hand of the true time concentric to the switching of the movement.

Technological background of the invention

As we know, there is a gap between the true solar time which corresponds to the duration that elapses between two consecutive zenith passages of the Sun at the meridian of the same place, and the mean solar time or civil time which is the average, made over the year, the duration of all solar days true. This difference between the civil time and the true time reaches +14 min 22 s on February 11, and -16 min 23 s on November 4. These values vary little from year to year.

To indicate the time difference between the civil time and the true time, some timepieces include, in addition to the hand which indicates the minute of the civil time, a so-called time equation mechanism which includes a needle which moves next to a graduated scale to indicate the difference between the minute of the civil time and the minute of the solar time for a given day. This minute hand of the true time is actuated by a weather equation cam whose profile is determined by the difference between the mean solar time and the true solar time for all the days of the year.

Another mechanism for indicating the time difference between the civil and the real time is known as the walking time equation. The turnout of a timepiece equipped with a walking time equation mechanism comprises two concentric minute hands, one indicating the minute of the civil time, and the other indicating the minute of the true time. At any moment, the difference between the minute hand of the civil time and the minute hand of the true time is determined by the difference between the mean solar time and the true solar time for the day of the year considered. As in the case of the equation of time mechanism, the minute hand of the true time of a walking equation mechanism is actuated by a time equation cam.

The equation of time cam is rotated at the rate of one revolution per year from a date mechanism that can be simple or perpetual. The simple calendar is a mechanism arranged to indicate the day of the week, the day of the month, the month of the year or the phases of the Moon, but which does not take into account the variation of the number of days in the month. (months of 28, 29 or 30 days). In other words, the user of a watch having a simple date mechanism will have to perform a manual correction every month ends that are less than 31 days. For example, February 28 or April 30 will require manual intervention. With regard to the perpetual calendar mechanism, it allows, as a simple date mechanism, to indicate the day, the date, the month and the phases of the Moon. But unlike a simple date mechanism, a perpetual calendar mechanism automatically takes into account the length of the months (28, 29 and 30 days), without manual intervention. A perpetual calendar mechanism therefore automatically takes into account leap years.

An example of a walking time equation mechanism is disclosed by the European patent application EP 1 286 233 A1 in the name of the Claimant. The figure 1 attached to this patent application is resumption of the European patent application EP 1 286 233 A1 mentioned above and illustrates a walking time equation mechanism driven by a differential device.

In this figure is notably visible an equation cam of time 1 whose profile is determined by the difference, for each day of the year, between the mean solar time or civil time and the true solar time. This equation of time 1 cam is rotated at a rate of one revolution per year from a simple or perpetual calendar mechanism that includes the timepiece. Equation cam of time 1 carries a disc of months 2 which rotates at the same speed as it and which makes it possible to make coincide the position of this equation cam of time 1 with the date indicated by the date mechanism so that the minute hand of solar time 4 indicates the exact offset between the minute of the civil time and the minute of the solar time.

The date mechanism, simple or perpetual, can be of any known type and will not be described here in its entirety. For a good understanding, it suffices to know that this date mechanism drives the equation cam of time 1 at the rate of one complete revolution per year. However, it is shown for illustrative purposes only a date mobile 6 driving a needle 8 which indicates the date (1 to 31). This mobile date of 6 rotates at a rate of one complete turn per month. It is actuated by the date mechanism and drives the time equation cam 1 via an intermediate date wheel 10 which makes it possible to reverse the direction of rotation, and a reduction wheel 12 which makes it possible to reduce the speed of rotation. rotation of one full turn per month to one full turn per year.

The minute hand of the solar time 4 is driven by a differential gear device 14 which has respective inputs a gear train driving a minute hand of the civil time 18, and a rake 20 which cooperates with the time equation cam 1 (on the figure 1 , the rake 20 is represented in its two extreme positions, once in solid line, and the other time in dotted lines). More precisely, as is visible on the figure 1 , the differential gear device 14 comprises at least one and, preferably, two planet gears 22 driven by the timer of the watch movement of the watch. These two planet gears 22 are able to turn on themselves and to roll on the internal toothing 24 of an equation wheel of time 26. The latter also has on its outer periphery a first toothed sector 28 by which it co-operates with a second toothed sector 30 which is provided with the rake 20 at one of its ends. This rake 20 is subjected to the return action of a spring (not shown) attached to the frame of the watch and which tends to apply a feeler 32 forming the other end of the rake 20 against the profile of the equation cam The solar weather display gear includes a sun time display pinion 34 placed in the center of the differential gear device 14. This sun time display pinion 34 meshes with the planet gears 22, and on the other hand a display wheel of the solar time 38 which meshes with a roadway 40 on the barrel from which is driven the minute hand of the solar time 4. This wheel 38, 40 allows to to return the display of the solar minute to the center 42 of the clockwork movement of the watch, so that the minute hand of the solar time 4 is concentric with the minute hand of the civil time 18.

The walking time equation mechanism just described works as follows.

In normal operation of the watch, the time equation cam 1, the rake 20 and therefore the equation wheel of time 26 are immobile. On the other hand, the planet gears 22 are driven by the watch movement of the watch. They therefore turn on themselves and roll on the internal toothing 24 of the equation wheel of time 26, driving the display pinion of the solar time 34 in rotation, which allows the minute hand of the solar time 4 to turn concomitantly with the minute hand of civil time minutes 18. The difference between the minute hand of the solar time 4 and the minute hand of the civil time 18 therefore remains constant over a period of 24 hours.

Once a day, around midnight, the equation cam of time 1 rotates, driven by the date mechanism that moves the calendar from one day to the next. At this precise moment, the feeler 32 which is in contact with the profile of the equation cam of the time 1 rotates the rake 20 in turn. This rake 20, by pivoting, drives the equation wheel of the time 26. rotation. The planet gears 22 being, during this brief time interval, substantially immobile (they turn one on their own in one hour), rotate on themselves while being rotated by the equation wheel of time 26, and in turn drive the sun time display gear 34 so as to again exactly adjust the position of the minute hand of the solar time.

The walking time equation mechanism described above thus allows, by means of a minute hand of the civil time and a minute hand of the solar time, to display at any time the time difference between the mean solar time and the true time. Note however that the differential gear device 14 is not located at the center 42 of the watch movement of the watch. So we have a construction that is not symmetrical, which is contrintuitive. In addition, because of the eccentric positioning of the differential gear device 14, it is necessary to provide an additional gear train (display wheel of the solar time 38 and 40) to reduce the display of solar time to center 42 of the watch movement and guarantee the concentricity of the minute hand of the civil time 18 and the minute hand of solar time 4. This additional gear train occupies space and can be a source of failure.

Summary of the invention

The present invention aims to overcome the problems described above as well as others by providing a walking time equation mechanism controlled by a differential gear device which is particularly more compact and therefore easier to integrate into a system. clockwork movement.

For this purpose, the present invention has for its first object a running time equation mechanism comprising a switch whose function is to indicate the civil time by means of an hour hand and a concentric minute hand, and a minute hand of the true time, concentric with the hands of the civil time, the equation mechanism of the walking time also including a time equation cam having a profile which is determined by the difference, for each day of the year, between the mean solar time or the civil time, and the solar time or true time, this equation of time being driven in rotation at the rate of one revolution per year by a clockwork movement, the position of the needle of the minutes of true time being determined by the position of the time equation cam, the walking time equation mechanism also including a differential gear device whose first input is const ituated by a floor secured to a gun of the minutes of the civil time on which is driven a minute hand of the civil time, and a second input is constituted by the equation of time cam, the differential gear device being arranged of concentric with the minute hand of true time.

The second subject of the present invention is a walking time equation mechanism comprising a switch whose function is to indicate the civil time by means of an hour hand and a concentric minute hand, and a minute hand. true time, concentric with the hands of the civil time, the equation mechanism of the walking time also including a time equation cam presenting a profile which is determined by the difference, for each day of the year, between the mean solar time or civil time, and the solar time or true time, this equation of time being driven in rotation at the rate of one revolution per by a clockwork movement, the position of the minute hand of the true time being determined by the position of the time equation cam, the walking time equation mechanism also comprising a differential gear device, one of which first entry is constituted by a floor secured to a gun of the minutes of the civil time on which is driven a minute hand of the civil time, and a second input is constituted by the equation of time cam, the differential gear device comprising a reducing satellite mobile via which the gun of the minutes of the civil time causes a gun of the hours of the civil time on which is driven the hour hand of the civil time, and a multiplier satellite mobile via which the canon of the hours of the civil time causes a canon of the minutes of the true time on which is driven the minute hand of the true time.

Thanks to these features, the present invention provides a walking time equation mechanism that is driven by a differential gear device provided with a reducing satellite gear via which the gun of the minutes of the civil time causes a gun of the hours of the civil time. on which is driven the hour hand of the civil time, and a multiplier satellite mobile via which the clock of the hours of the civil time causes a canon of the minutes of the true time on which is driven the minute hand of the true time. Proposing to integrate into the heart of the differential gear device the functions that make it possible to produce the civil time time from the minute of the civil time, and the minute of the true time from the time of the civil time and a time equation cam, makes it possible to obtain a more compact differential gear device whose reduction and multiplier satellite mobiles are brought back to the center of the watch movement. The differential gear device according to the invention is thus easier to accommodate in the watch movement it equips, which makes it possible to reduce the bulk of the watchmaking movement and to have more space to house the other components of the movement.

According to a preferred embodiment of the invention, the reducing satellite mobile and the multiplying satellite mobile rotate on themselves by describing a circular trajectory, preferably of the same radius, centered on the gun of the minutes of the civil time.

The differential gear mechanism according to the invention has fewer components and is therefore more reliable. In addition, it has a radial general symmetry centered on the center of the movement, which facilitates assembly and arrangement.

Brief description of the figures

• la figure 1, déjà citée, est une vue d'un mécanisme d'équation du temps marchante selon l'art antérieur mû par un dispositif différentiel ;
• la figure 2 est une vue de dessus du dispositif d'équation marchante selon l'invention ;
• la figure 3 est une vue en coupe selon la ligne A-A de la figure 2 ;
• la figure 4 est une vue en coupe selon la ligne B-B de la figure 2, et
• la figure 5 est une vue en coupe selon la ligne C-C de la figure 2.

Other features and advantages of the present invention will emerge more clearly from the following detailed description of an example embodiment of a running time equation device according to the invention, this example being given purely for illustrative purposes and not limiting only in connection with the appended drawing in which:

• the figure 1 , already cited, is a view of a walking equation of time mechanism according to the prior art moved by a differential device;
• the figure 2 is a top view of the walking equation device according to the invention;
• the figure 3 is a sectional view along line AA of the figure 2 ;
• the figure 4 is a sectional view along line BB of the figure 2 , and
• the figure 5 is a sectional view along the line CC of the figure 2 .

Detailed description of an embodiment of the invention

The present invention proceeds from the general inventive idea of equipping an equation mechanism with the walking time of a differential gear device which is capable of indicating both the civil time by means of a civil time hour hand and a civil time minute hand, and the true time minute by means of a second hand of the civilian time concentric minute to the hands of the civil time. The differential gear device has for respective PTOs a mobile of a finishing gear of the watch movement on the one hand, and a time equation cam on the other hand. According to the invention, a multiplication function which makes it possible to pass from the minute of the civil time to the time of the civil time, and a multiplication function which makes it possible to pass from the time of the civil time to the minute of the true time are integrated in the center of the differential gear device, which makes the equation mechanism walking time more compact and therefore easier to arrange in the watch movement.

The object of the present invention is to integrate in a timepiece such as a wristwatch a walking equation mechanism, that is to say a mechanism whose switch has two concentric minute hands. , one indicating the minute of the civil time and the other indicating the minute of the true time. For this purpose, and as can be seen on the figure 2 the equation mechanism of the walking time according to the invention, generally designated by the general numerical reference 44, comprises on the one hand a conventional switch whose function is to indicate the civil time by means of a hand of 46 hours and a minute hand 48, and second hand a minute hand of the true time 50, concentric with the minute hand of the civilian time 48, and which indicates the minute of the true time. To enable the wearer of the watch to easily differentiate between the minute hand of the civilian time 48 and the minute hand of the true time 50, the latter may, for example, end with a representation of the astrological symbol of the sun 52. As will be seen in more detail later in this description, the exact position of the minute hand of the true time 50 for a given day is determined once in 24 hours, around midnight, and then both. hands of the minutes of the civil time 48 and the true time 50 se move together, the gap between these two needles 48 and 50 remaining constant for the given day.

We can also see on the figure 2 a part of the equation of walking time equation 44 according to the invention, and in particular a time equation cam 54 whose profile, let us recall, is determined by the difference between the mean solar time or civil time, and the true time or solar time for each day of the year.

Always in connection with the figure 2 it can be seen that the time equation cam 54 is fixed on an equation wheel of time 56 which is driven at the rate of one complete revolution per year by a simple or perpetual calendar mechanism (not shown) that the timepiece. This date mechanism can be of any known type and will not be described here in detail. It is sufficient, in fact, for a good understanding of the invention, to know that this date mechanism causes the equation wheel of the time 56 on which is fixed the time equation cam 54 at a rate of one complete revolution per year. The date mechanism comprises a date wheel 58 which rotates at a rate of one complete revolution per month by driving a date indicator 104. On the other hand, the equation of time wheel 56 is driven by the date wheel 58 via an intermediate reference wheel of date 60 for reversing the direction of rotation, and a reduction wheel 62 which reduces the rotational speed of a complete revolution per month to one complete revolution per year.

According to the invention, the minute hand of the true time 50 is driven by a differential gear device 64 which has respective inputs (see FIG. figure 3 ) a mobile 66 of a work train driving the minute hand of the civil time 48 and a time equation lever 68 which cooperates with the time equation cam 54. More precisely, as visible on the figure 3 a gun of the minutes of the civil time 70 is driven by the mobile 66 of the finishing gear of the timepiece of the timepiece via a roadway 72 secured to the Civil time minute gun 70. In turn, the civil time minute gun 70 drives a reducing satellite 74 formed of a first satellite wheel 76 and a first satellite pinion 78 integral with the first wheel of the satellite 76.

The reducing satellite mobile 74 is pivotally mounted around a first pin 80 driven into an upper differential frame 82 which is secured to a gun of the hours of civil time 84 on which is driven the hour hand of the civilian time 46. Trained by the canon of the minutes of the civil time 70 via the first satellite wheel 76, the first sun gear 78 rolls on a first internal toothing 86 of a first differential ring 88 which is carried by the watch movement and which is fixed . By rolling on the first internal toothing 86 of the fixed differential ring 88, the first sun gear 78 thus rotates the upper differential frame 82 and thus the gun of the civil time hours 84 which is integral with the differential upper frame 82. By a judicious choice of the gear ratios between the civil time minute gun 70, the first satellite wheel 76, the first satellite gear 78 and the fixed differential ring 88, a reduction of one twelfth is achieved between the minute of the civil time and the time of the civil time and one thus obtains the display of the civil time. In other words, the reducing satellite mobile 74 makes it possible, by a reduction of one twelfth, to go from the minute of the civil time to the time of the civil time.

As visible on the figure 4 a multiplier satellite mobile 90 is formed of a second satellite wheel 92 and a second satellite gear 94 integral with the second satellite wheel 92. The multiplier satellite mobile 90 is mounted free around a second pin 96 driven in the upper differential frame 82 which is secured to the gun of the hours of the civil time 84. When the canon of the hours of the civil time 84 and thus the upper differential frame 82 rotate, they cause the second pin 96 and, consequently, the mobile satellite multiplier 90 whose second satellite gear 94 rolls on a second internal toothing 98 a mobile differential ring 100 which will be seen below that it is in engagement with the time equation cam 54. The second satellite wheel 92 in turn drives a suntime minute gun 102 on which the minute hand of the true time 50 is driven away. By a judicious choice of the gear ratios between the civil time hour gun 84, the second satellite wheel 92, the second satellite gear 94 and the mobile differential ring gear. 100, a multiplication by twelve is made between the time of the civil time and the minute of the true time and one thus obtains the display of the minute of the true time. In other words, the multiplier satellite mobile 90 makes it possible, by a multiplication by twelve, to go from the time of the civil time to the minute of the true time.

It follows from the foregoing that the reducing satellite mobile 74 and the multiplying satellite mobile 90 rotate on themselves by describing a circular trajectory centered on the gun of the minutes of the civil time 70. Preferably, the reducing satellite mobile 74 and the mobile multiplier satellite 90 move on a circle of the same radius, centered on the gun of the minutes of the civil time, being angularly spaced.

The mobile differential crown 100 is pivotally controlled by the time equation lever 68 provided with a probe nose 106 through which the time equation lever 68 is in contact with the profile of the cam. Equation of time 54. This time equation lever 68 is held resiliently against the profile of the equation of time cam 54 by a spring 108. This equation of time lever 68 is also provided with a first tooth 110 engaged with a corresponding second tooth 112 provided on the mobile differential ring 100 to control the movement of the latter. It is understood that at a time close to midnight when the date mechanism changes date, it controls the advance of a step of the date wheel 58. During this brief moment when the change of date occurs, the differential upper frame 82 and thus the canon of the hours of the civil time 84 can be considered as immobile. By swiveling, the Mobile differential ring 100 drives the second satellite pinion 94 and thus the second satellite wheel 92 which, in turn, meshes with the gun of the minutes of solar time 102 on which the minute hand of the true time 50 is driven. The position of the minute hand of the true time 50 is thus adjusted for the day to come.

We are now going back to figure 5 on which it is seen that at least one and preferably two screws 114 make it possible to close the upper differential frame 82 on a lower differential frame 116. The upper differential frames 82 and lower 116 therefore rotate together when the differential gear device 64 according to the invention operates.

It goes without saying that the present invention is not limited to the embodiment which has just been described and that various modifications and simple variants can be envisaged by those skilled in the art without departing from the scope of the invention as defined by the appended claims.

Nomenclature

1.

Equation cam of time

2.

Disc of the months

4.

Needle of minutes of solar time

6.

Mobile calendar

8.

Needle

10.

Intermediate calendar return wheel

12.

Mobile discount

14.

Differential gear device

18.

Needle of the minutes of the civil time

20.

Rake

22.

Satellite sprockets

24.

Internal teeth

26.

Equation wheel of time

28.

First toothed sector

30.

Second sector gear

32.

feeler

34.

Display pinion of solar time

38.

Display wheel of solar time

40.

roadway

42.

Center

44.

Equation mechanism of walking time

46.

Needle of the hours of the civil time

48.

Needle of the minutes of the civil time

50.

Needle of minutes of true time

52.

Astrological symbol of the sun

54.

Equation cam of time

56.

Equation wheel of time

58.

Date wheel

60.

Intermediate calendar return wheel

62.

Mobile discount

64.

Differential gear device

66.

Mobile

68.

Equation lever of time

70.

Canon of the minutes of the civil time

72.

roadway

74.

Mobile satellite reducer

76.

First satellite wheel

78.

First satellite gear

80.

First pin

82.

Differential upper frame

84.

Canon of the hours of the civil time

86.

First internal toothing

88.

Fixed differential crown

90.

Mobile satellite multiplier

92.

Second satellite wheel

94.

Second satellite gear

96.

Second pin

98.

Second internal toothing

100.

Mobile differential crown

102.

Canon's minutes of true time

104.

Date indicator

106.

Probing Beak

108.

Spring

110.

First tooth

112.

Second tooth

114.

Screw

Claims (16)

Walking time equation mechanism comprising a switch whose function is to indicate the calendar time by means of an hour hand (46) and a minute hand (48) concentric, and a minute hand of time true (50), concentric with the hands of the civil time (46, 48), the walking time equation mechanism (44) also including a time equation cam (54) having a profile which is determined by the difference, for each day of the year, between the mean solar time or civil time, and the solar time or true time, this equation of time cam (54) being rotated at a rate of one revolution per year by a motion of time, the position of the minute hand of the true time (50) being determined by the position of the time equation cam (54), the walking time equation mechanism (44) also comprising a device with differential gear (64) of which a first input is killed by a roadway (72) integral with a gun of the minutes of the civil time (70) on which is driven a minute hand of the civil time (48), and a second input is constituted by the equation of time cam (54), the differential gear device (64) being arranged concentrically with respect to the minute hand of the true time (50). Walking time equation mechanism including a switch whose function is to indicate the civil time by means of an hour hand (46) and a minute hand (48), and a minute hand of true time (50), the walking time equation mechanism (44) also including a time equation cam (54) having a profile which is determined by the difference, for each day of the year, between the mean solar time or time, and the solar time or true time, this equation of time cam (54) being rotated at a rate of one revolution per year by a clockwork movement, the position of the minute hand of the true time (50) being determined by the position the time equation cam (54), the walking time equation mechanism (44) also including a differential gear device (64), a first input of which is a roadway (72) integral with a gun civil time minutes (70) on which a calendar minute hand (48) is driven, and a second input of which is the time equation cam (54), the differential gear device (64) comprising a reducing satellite mobile (74) via which the gun of the minutes of the civil time (70) causes a gun of the hours of the civil time (84) on which is driven the hour hand of the civil time (46), and a mobile multiplier satellite (90) via which the clock of the civil time hours (84) causes a canon of the minutes of the true time (102) on which is driven the minute hand of the true time (50). A walking time equation mechanism according to claim 2, characterized in that the reducing satellite dish (74) reduces the rotational speed from one full revolution per hour to one full revolution per twelve hours, and that Mobile satellite multiplier (90) makes it possible to increase the rotational speed of a complete revolution in twelve hours to one complete revolution per hour. A walking equation mechanism according to any one of claims 2 or 3, characterized in that the reducing satellite dish (74) and the multiplying satellite dish (90) rotate on themselves in a circular path centered on the barrel of the minutes from civil time (70). A walking equation mechanism according to claim 4, characterized in that the reducing satellite dish (74) and the multiplying satellite dish (90) are equidistant from the civil time minute gun (70). Walking time equation mechanism according to one of Claims 2 to 5, characterized in that the reducing satellite gear (74) and the multiplying satellite gear (90) are carried free in rotation by a differential frame whose gun of the hours of the civil time (46) is solidary. Walking time equation mechanism according to claim 6, characterized in that the reduction gear mobile (74) is pivotally mounted about a first pin (80) driven into the differential upper frame (82). A walking time equation mechanism according to claim 7, characterized in that the reducing satellite dish (74) comprises a first satellite wheel (76) integral with a first satellite pinion (78). A walking time equation mechanism according to claim 8, characterized in that the civil time minute gun (70) meshes with the first satellite wheel (76), and that the first satellite gear (78) rolls on a first internal toothing (86) of a fixed differential ring gear (88), thereby rotating the differential upper frame (82). Walking time equation mechanism according to any one of claims 6 to 9, characterized in that the multiplier satellite mobile (90) is pivotally mounted about a second pin (96) driven into the differential upper frame (82). ). A walking time equation mechanism according to claim 10, characterized in that the multiplier satellite mobile (90) comprises a second satellite wheel (92) integral with a second satellite gear (94). A walking time equation mechanism according to claim 11, characterized in that the second satellite wheel (92) meshes with the true time minutes gun (102), and that the second satellite gear (94) rolls on a second internal toothing (98) of a movable differential ring (100) which is kinematically connected to the time equation cam (54). Walking time equation mechanism according to claim 12, characterized in that the movable differential ring (100) is pivotally controlled by a time equation lever (68) provided with a sensing nose (106) by the intermediate of which the time equation lever (68) follows the profile of the time equation cam (54). A walking time equation mechanism according to claim 13, characterized in that the time equation lever (68) is held resiliently against the profile of the time equation cam (54) by a spring (108). ). A walking time equation mechanism according to any one of claims 13 or 14, characterized in that the equation of time lever (68) is provided with a first tooth (110) engaged with a second tooth (112). ) corresponding provided on the mobile differential ring (100) to control the displacement of the latter. Walking time equation mechanism according to one of Claims 6 to 15, characterized in that the upper differential frame (82) is fixed to the lower differential frame (118) by means of a screw (130) .

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