EP3701336B1 - Correction device for a timepiece - Google Patents

Description

Technical area

The present invention relates to the field of watchmaking. It relates more particularly to a correction device for a timepiece.

State of the art

In timepieces comprising not only a display of the current time but also a device for displaying other information such as the date, the day of the week, the month, the year or the like, a device correction is necessary to allow the user to adjust the information displayed by this device. This adjustment can be carried out by means of the time-setting rod, by a dedicated rod, by other dedicated means such as one or more pushers or the like. Some of these correction devices can adversely affect the movement, for example by applying a torque which can damage the movement if the manual correction is done around midnight, while the drives of the display devices are running. produce.

For this reason, the document FR2541005 proposes to link the movement to a date display device by means of a differential gear which is part of the correction device. The first input of this differential is driven by the movement, the second input is driven by an external maneuvering member, such as a time-setting rod, and the output in turn drives the display of the date. By means of the differential, no harmful torque can be exerted on an element of the movement during a correction, and this correction can be done in both directions if the display device is arranged appropriately.

In some complex display devices, such as perpetual calendars, the presence of several displays, the information of which is linked (for example the date, the month, the year, the moon phase, etc.), the synchronization of the display of each of this information is essential so that the device displays the information correctly and also for the indications to advance at the right time.

When the movement has been stopped for a certain time, it is often necessary to correct several of this information, and thus restore their synchronization.

One solution often applied is that of providing correction means dedicated to each of the sub-displays (date, day, month, year, moon phase, etc.) which are associated with push-buttons or correctors. Each push-button thus acts on the corresponding sub-display, which requires several operations to update the mechanism. However, these correctors typically act in only one direction, so to obtain a correction of one step in the other direction, it is necessary to travel the rest of the cycle in the direction of the correction, which may, depending on the construction of the display device, also disrupt a downstream sub-display. In such a case, the latter must also be corrected in turn.

The document EP0191921 describes a solution to this problem by proposing a perpetual calendar in which the correction of the calendar data is effected by means of the time-setting stem. It is thus impossible to desynchronize the various information. However, the kinematics of the movement only allow correction in one direction.

The aim of the invention is therefore to provide a timepiece in which the aforementioned defects are at least partially overcome.

Disclosure of the invention

More specifically, the invention relates to a correction device for a timepiece, which comprises a differential gear having a first input, a second input and an output.

The first input of said differential is arranged to be driven by a watch movement, for example by being driven directly by the movement, at the rate of one revolution in 12 hours.

The second input is in kinematic connection with a correction gear extending from a control member and comprising a clutch making it possible to establish and interrupt the kinematic connection between said control member and said second input.

The output is arranged to drive a display device for the watch movement, and the angular position of the output is defined as a function of the angular position of said first input as well as that of said second input, each of the inputs thus providing a contribution. to the angular position of the outlet.

According to the invention, said correction device further comprises a memory cam in desmodromic connection with the second input. This memory cam is subjected to a return force supplied by an elastic member, such as a spring, tending to maintain the memory cam in at least one predetermined angular position when the kinematic connection between the control member and the second entry is interrupted, i.e. when no correction is made. When the kinematic link is established during a correction, the elastic member allows rotation of the second input under the control of the control member, which makes it possible to perform a correction of the associated display device.

Finally, the correction device is arranged, in particular at the level of the gear ratios concerned, to ensure that the incidence of the rotation of the second input during a correction, on the angular position of the output is canceled when the memory cam is in said at least one predetermined angular position. In other words, the predetermined angular position of the memory cam returns the second input to a "neutral" position when the kinematic connection between the control member and the second input is interrupted.

During a correction, the angular position of the second input contributes to define in any way the angular position of the output, adding to or deducing from the angular position defined by the first input. In such a case, the output is out of sync and out of sync with the first input. Since the memory cam is linked desmodromic with the second input, it is designed to “store” the angular deviation corresponding to this offset. When the kinematic connection with the control member is disengaged at the end of the correction, the action of the return force on the memory cam causes the second input so that this difference is canceled. The contribution of the second input to the angular position of the output is thus made zero by putting said input in a corresponding angular position and the synchronization between the output and the first input is reestablished. Therefore, the drive of the display device by the output will take place at the desired time, during normal operation.

Other advantageous features are mentioned in the dependent claims.

Brief description of the drawings

• Figure 1 est une vue isométrique d'un dispositif de correction selon l'invention ;
• Figure 2 est une vue isométrique du dispositif de correction de la figure 1, illustré conjointement avec des mobiles avec lesquels il interagit ;
• Figure 3 est la vue de la figure 2 coupée selon un plan qui intersecte l'axe de rotation de l'engrenage différentiel et qui s'étend depuis la tige de correction ;
• Figure 4 est une vue isométrique d'une partie de l'engrenage différentiel illustré dans les figures 1 à 3 ; et
• Figure 5 est une vue semblable à celle de la figure 4, l'une des planches dentées ayant été enlevée.

Other details of the invention will emerge more clearly on reading the following description, given with reference to the appended drawings in which:

• Figure 1 is an isometric view of a correction device according to the invention;
• Figure 2 is an isometric view of the blood pressure correction device figure 1 , illustrated in conjunction with the mobiles with which it interacts;
• Figure 3 is the view of the figure 2 cut along a plane which intersects the axis of rotation of the differential gear and which extends from the correction rod;
• Figure 4 is an isometric view of part of the differential gear shown in figures 1 to 3 ; and
• Figure 5 is a view similar to that of the figure 4 , one of the toothed boards having been removed.

Embodiment of the invention

The figure 1 illustrates an embodiment of a correction device 1 according to the invention, given by way of non-limiting example. This correction device 1 is intended to correct the information displayed by any display device, such as an annual calendar mechanism, but can also be applied to a simple, perpetual or similar calendar. This correction can advantageously be carried out in both directions.

The device 1 comprises a differential gear 3, certain details of which are better visible in the figures 4 and 5 . The differential gear 3 has a first input 5 intended to be driven by a watch movement. As in the example, the device can be arranged on a module intended to be driven by a basic movement (not shown), but the application to an integrated construction is also possible.

The movement is intended to drive the first input 5 at an ad hoc angular speed (typically one revolution in 12 hours), and takes the form of a toothed wheel rotatably attached to a sun gear 7 located at the geometric center of the differential 3 The first input 5 can be driven by any kind of drive system, such as for example meshing with the hour wheel of the movement. In the present case, the first input is integral in rotation with the hour wheel of the movement and is driven at the rate of one revolution in 12 hours. However, other training speeds are possible.

The differential 3 further comprises a second input 9, which is a planet carrier provided with an external toothing and on which a plurality of planet gears 17 are pivoted. The latter mesh with the sun gear 7. The external teeth of this planet carrier meshes with a correction gear 11 which is in a disengageable kinematic connection with a correction member 19, in the form of a correction rod 19. This rod 19 can also act as a winding stem.

Alternatively, the correction member can take other forms, such as a rotating bezel or a rotating bottom. A person skilled in the art could also arrange two rapid correction pushers, one for advancing and the other for retreating the planet carrier, by coordinating the engagement and disengagement of the correction chain.

The output 13 of the differential gear comprises two toothed plates 13a, 13b each having 24 teeth and superimposed with respect to one another and mutually integral in rotation, for example by means of a key-groove system c . These boards 13a, 13b are integral in rotation with a ring 15 provided with an internal toothing which meshes with the planet gears 17. The number of boards and planet gears as well as their arrangement in an epicyclic train system in the plane ( “flat” planetary differential) or in space (“spherical” planetary differential) can be chosen according to the needs of the manufacturer. Of course, other constructions of differential gears are within the abilities of those skilled in the art, and that described here is in no way limiting.

Thanks to this construction, during normal operation of the display device, that is to say when the movement is operating and there is no correction made, the correction gear 11 and therefore the second input 9 remain blocked at rest as described below. The output 13 is therefore driven exclusively as a function of the rotation of the first input 5, via the sun gear 7 and the satellites 17. The direction of rotation of the output 13 is thus the reverse of that of the first input. 5, and it is subjected to a reduction in angular speed, due to the gear ratio of the differential. In this case, the first input 5 rotates in 12 hours and its gear ratio with the output 13 is 0.5. Consequently, the latter performs one revolution in 24 hours, as is appropriate for the training of a date device. As such, the upper board 13a carries a drive tooth 37 which is longer than the other teeth of said board. The lower board 13b also carries longer drive teeth as is generally known in the context of the training of annual or perpetual calendar devices, to perform end-of-month training of less than 31 days and / or for operate another display device. Other rotational speeds are of course possible depending on the construction of the display device and of the differential gear 3.

During a correction, the first input 5 remains (almost) motionless, under the action of the movement and the escapement, and the second input 9 pivots following a rotation of the correction rod 19 which is transmitted by the 'intermediary of the correction gear 11. The rotation of the second input 9 is transmitted subsequently to the output 13 by the rotation of the satellites 17 around the center of the differential, as well as by the rolling of the latter on the sun gear 7 which remains (almost) motionless. The directions of rotation of the second input 9 as well as of the output 13 are thus the same, but the speed of rotation of the output is lower than that of the second input, at a ratio of 2/3 in the mode. realization illustrated.

In doing so, and as mentioned in the preamble, the correction gear does not exert any influence on the basic movement during a correction, and the rotation of the output 13 is a function of each of the two inputs 5, 9. In one case Typically, output 13 drives the display device one step for each revolution it takes. It will be noted that it is also possible to provide several correction steps by complete rotation of the output 13, depending on the construction of the display device and the boards 13a, 13b. For example, every third or quarter (or other division) of a turn of the output could cause the display device to take one correction step, as appropriate.

So that, following a correction, the angular position of the output 13 remains synchronized with respect to the first input 5, and that the display device is driven at the right moment, that is to say at the around midnight, the device 1 comprises means which make it possible to return the outlet 13 substantially to its initial angular orientation, prior to the correction, once the correction has been completed.

To do this, the correction gear 11 comprises on the one hand a clutch 21 making it possible to establish and interrupt the kinematic connection between the correction rod 19 and the second input 9 according to the axial position of the rod 19 and, d 'on the other hand a memory cam 23.

The clutch 21 can be of any type, such as sliding pinion and pull-tab, rocker, horizontal clutch, one-way snap or similar, for example as illustrated in the document CH1016 . In the illustrated embodiment, the clutch comprises a sliding pinion 25 actuated by a non-illustrated pull tab. The axial position of the sliding pinion 25 determines whether the latter is rotatably linked to the rod 19 or not. Other means for controlling the clutch 21 are within the abilities of those skilled in the art.

The memory cam 23 is integral in rotation with a wheel 27 which is in desmodromic connection with the second input 9. In the illustrated embodiment, the wheel 27 meshes with a mobile 29 forming part of the kinematic chain linking the clutch. 25 to the second input 9. Alternatively, the memory cam 23 can be arranged integral in rotation with an element of this kinematic chain or be integrated into the second input 9 of the differential gear 3. Again alternatively, the memory cam 23 can be linked with said second input 9 by means of its own dedicated cog.

The shape of the memory cam 23 was chosen to optimize the torque available after correction. In most cases, a correction will be made in the direction of advancing the indications supplied by the display device following the stopping of the part for a certain time. Corrections in the other direction are rarer, and therefore the memory cam 23 may have an asymmetric shape arranged to provide more torque in one direction of rotation than in the other. However, it is quite possible to use a cam which is symmetrical or which has another suitable shape.

During normal operation of the part, the clutch 21 is disengaged and the memory cam 23 is positioned by a return force supplied by a spring 31, the position of which is controlled by the axial position of the rod 19. In this state, the spring 31 is positioned so as to exert sufficient force on the memory cam 23 so that it blocks the correction gear 11 against any parasitic torques emanating from the rotation of the first input 5 and of the output 13. Thus, the second inlet 9 is also blocked in a predetermined angular position of such so that the output 13 remains synchronized with the first input 5. In the illustrated embodiment, the spring 31 is mounted on the rod 19, but other constructions are within the abilities of those skilled in the art. It is also possible that the spring 31 is mounted on a frame element independently of the control member 19.

During a correction, the axial displacement of the rod 19 raises the spring 31 so that the latter exerts less pressure on the memory cam 23, in order to facilitate a correction operation. The output 13 of the differential 3 is pivoted as a function of the rotations of the rod 19 and the display device that it controls can be corrected.

During the correction, the memory cam 23 is also rotated. In the illustrated embodiment, the memory cam 23 is heart-shaped having a single lobe, and its gear ratio with the second input 9 is chosen such that the memory cam 23 rotates at the rate of one lobe. full turn by rotation of the output 13 under the control of the angular displacements of the second input 9. To this end, since the gear ratio between the second input 9 and the output 13 is 2/3 (which implies that 1, 5 turns of the second input 9 drives the output 13 at the rate of one turn), that between the second input 9 and the memory cam 23 is 1.5. These ratios can be modified according to the needs of the manufacturer. Alternatively, the memory cam 23 may have several lobes and rotate at the rate of, for example, one third or one quarter of a turn per complete rotation of the output 13, depending on the number of lobes.

In general, the second inlet 9 will have several angular orientations for which its contribution to the angular position of the outlet 13 is zero, these positions being separated from each other by more than 360 °. Such a unique angular orientation occurs exclusively in the case of a 1: 1 gear ratio between the second input 9 and the output. For the general case, the person skilled in the art knows how to calculate by the Willis formula the gear ratios necessary in order to ensure that the positioning of the memory cam 23 by the return force cancels out the effect of the second input 9 and thus re-establishes the synchronization between the first input 5 and the output 13.

In view of the above, it will be understood that the memory cam 23 “stores” the contribution to the angular position of the output 13 supplied by the second input 9.

After the user has made a correction, he returns the rod 19 to its initial axial position, which disengages the clutch 21. The spring 31 again bears against the correction cam 23, which tends to cause the clutch. correction gear 11, which is now free to rotate. The first input 5 remaining (almost) blocked by the kinematic chain which drives it, the return force exerted by the spring 31 on the memory cam 23 causes the wheel 27 as well as the rest of the correction gear 11 to pivot until that the cam 23 returns to its initial angular position, as illustrated in the figure 1 . In doing so, the second input 9 is controlled such that its contribution to a possible fraction of a turn of the output 13 is canceled. The output 13 thus returns to the angular position that it would have had in the absence of a correction, and its angular position is again only defined by the first input 5. In other words, the output 13 does not perform only full revolutions after addition or subtraction performed under the control of the memory cam, notwithstanding any impact of the first entry during correction. In the context of a perpetual calendar, this causes the date to jump around midnight even after a correction.

The figures 2 and 3 illustrate the correction device 1 of the invention in combination with kinematically adjacent components of an annual calendar device, in order to better illustrate the meaning of the functionality of said correction device 1.

The annual calendar device comprises a programming wheel 33 which comprises a date plate 35 having 31 teeth as well as a correction plate 39 coaxial with the date plate 35. The latter is designed to be driven at the rate of one step. per 24 hours via the actuating tooth 37 which extends from the board toothed 13a of the outlet. The toothed board 13b includes several longer teeth which interact with a corresponding tooth of the correction board 39 in order to advance the programming wheel at an additional pitch at the end of the months having thirty days. In the case of a perpetual calendar device, it is also possible to provide one or more additional correction plates (not shown) integral in rotation with the date plate 35 which also interact with the lower plate 13b or with a plate. additional integral in rotation of the boards 13a, 13b, in order to automatically perform a correction at the end of February in a known manner. To this end, the various boards each have a suitable number of teeth, depending on the number of days of the month. In the case of a simple date mechanism, the correction plate 39 as well as the plate 13b can be omitted.

Located on the left in the figures is a display mechanism for the days of the week as well as the moon phases 41, which is driven by the intermediary of the lower board 13b of the outlet 13, and which does not have to be described. more in detail.

Thanks to the construction of the boards 13a, 13b of the outlet 13 as well as of the programming wheel 33, in particular at the level of the single long tooth 37 of the upper board 13a of the outlet 13, it is understood that the outlet 13 must pivot at due to one complete revolution in steps of correction of the programming wheel 33. Furthermore, if after a correction, the output 13 is out of order with respect to the programming wheel 33, its advancement will take place at an unwanted time.

Consequently, in the absence of the memory cam 23, it is almost impossible that the user can return the output 13 to the correct angular orientation after correction, which the correction device 1 according to the invention automatically does as described. above.

Although the invention has been particularly shown and described with reference to particular embodiments, other variations and constructions of the correction device 1 are possible without departing from the scope of the invention as defined in the claims.

In this regard, it may be mentioned that the correction device can directly or indirectly drive a display member, for example of a simple date, the construction of the output 13 being adapted accordingly. For example, the output could simply carry a single finger for the direct or indirect drive of a date crown.

Furthermore, with regard to the differential gear, it is not mandatory that its output 13 directly carry a board 13a, 13b or a similar element which interacts directly with a programming wheel 33, a date wheel set or a device. display. Indeed, the output 13 can be a toothed wheel which in turn drives an intermediate mobile which directly or indirectly drives such an element.

Claims (11)

1. Correction device (1) for a timepiece, comprising a differential gear (3) having a first input (5), a second input (9) and an output (13), wherein:

   - the first input (5) is arranged to be driven by a horological movement;

   - the second input (9) is kinematically linked with a correction gear train (11) extending from a control organ (19) and comprising a coupling (21) that makes it possible to establish and break the kinematic link between said control organ (19) and said second input (9);

   - the output (13) is arranged to drive a display device of said horological movement, the angular position of said output (13) being defined as a function of the angular position of said first input (5) and of that of said second input (9), characterized in that said correction device (1) further comprises a memory cam (23) linked in a desmodromic manner with said second input (9),

   in that said memory cam (23) is subjected to a return force imparted by an elastic organ (31) tending to keep said memory cam (23) in at least one predetermined angular position when said kinematic link between said control organ (19) and said second input (9) is broken, said elastic organ (31) being further arranged to allow a rotation of said second input (9) under the control of said control organ (19) when said kinematic link is established upon operation of the correction device,

   and in that said correction device (1) is arranged such that the incidence of the rotation of the second input (9), during a correction, on the angular position of the output (13) is cancelled when said memory cam (23) is in said at least one predetermined angular position.
2. Correction device (1) according to Claim 1, wherein said correction gear train (11) comprises a coupling (21) situated kinematically between said memory cam (23) and said control organ (19).
3. Correction device (1) according to one of the preceding claims, wherein said memory cam (23) is secured in rotation with a wheel (27) which forms part of said correction gear train (11) or which meshes with a single other wheel of said correction gear train (11).
4. Correction device (1) according to one of the preceding claims, wherein said elastic member (31) is arranged so as to be displaced under the control of the translational displacements of the control organ (19).
5. Correction device (1) according to one of the preceding claims, wherein:

   - said first input (5) is secured in rotation with a sun pinion (7);

   - said second input (9) is a satellite-holder provided with at least one satellite pinion (17) engaged with said sun pinion (7); and

   - said output (13) comprises a toothed crown (15), an internal toothing of which meshes with said sun pinion (7).
6. Correction device (1) according to Claim 5, wherein said output (13) is arranged to carry out one rotation every 24 hours in normal operating mode.
7. Correction device (1) according to one of Claims 5 and 6, wherein said first input (5) is arranged to carry out one rotation every 12 hours in normal operating mode.
8. Correction device (1) according to one of Claims 5-7, wherein said output (13) comprises at least one toothed platform (13a, 13b) provided with at least one driving tooth (37).
9. Correction device (1) according to one of Claims 5-8, wherein said output (13) comprises a plurality of toothed platforms (13a, 13b) arranged to cooperate with a programme wheel (33) comprised by a perpetual calendar device.
10. Horological movement provided with a correction device (1) according to one of the preceding claims.
11. Timepiece comprising a movement according to the preceding claim.

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