Timepiece movement provided with mechanism for driving time-skipping indicator

Abstract

A timepiece movement (2) is provided with an indicator (4) and comprises a mechanism (6) for driving such an indicator jump, comprising a wheel platform (8), a rigid portion (10) defining a driving finger (12), and a spring (16), the first end of which is attached to the wheel platform for rotation therewith and the second end of which is attached to the rigid portion for rotation therewith. The mechanism is arranged such that the spring contracts when this spring is loaded so as to be able to generate a time hopping of the indicator. When the spring contracts, the angular displacement of the drive fingers relative to the wheel platform is limited by an angular stop (28) which is attached to the wheel platform for rotation therewith. Preferably, the indicator and the mechanism are arranged such that, in normal operation, a time-hopping of the indicator cannot occur before the angular displacement has been stopped by the angular stop after a spring loading of the angular displacement prior to this time-hopping has ended and thus corresponds to the determined angular distance (alpha).

Description

Field of the Invention

[0001] The present invention relates to a watch movement provided with an indicator and comprising a mechanism for driving this indicator to jump in time, and also to a watch incorporating a watch movement provided with such a mechanism. In particular, the indicator is a date indicator. Background Art

[0002] Patent document EP 3828644 describes a mechanism for driving a jumping time indicator which advantageously overcomes the technical problems of the prior art by comprising a rigid drum finger and a spring, the rigid drum finger being rotatably and translatably guided by a hub passing through an oblong hole in the drum, the spring being arranged in this drum finger and connecting this drum finger to a wheel platform.

[0003] This drive mechanism has a number of drawbacks. Firstly, when the date ring is driven, the spring stretches, and when the spring is loaded, its coils are intended to bear against the inner wall of the drum, thus limiting the spring's stretch and preventing it from reaching the plastic range of the spring. This results in a sudden reduction in the effective length of the spring. Given the manufacturing tolerances of the various components, the loading time of this drive mechanism can vary because the time when the spring contacts the inner wall of the drum can change from one loading to the next, and the angular position of the contact zone can also change. This results in an inaccurate time for triggering the ring to move to the next date. Another problem is due to the fact that the driving force is transmitted to the finger via the coils of the spring, so the spring must be sufficiently rigid / stiff over its entire length, and more particularly over the portion located between the contact zone with the wall of the drum and the coupling member for coupling with this drum, the coupling member being arranged at the second end of the spring, and this portion must ultimately withstand all the additional torque generated from the moment of contact to the moment when the indicator makes a jump in time.

[0004] The illustration in the above-mentioned document shows that the coupling member of the spring is arranged in a shallow recess, and this member may be prone to disengaging from the shallow recess. The two lateral surfaces of the recess are parallel in the radial direction passing through the middle of the recess, and the coupling member has two radial side surfaces. The angular width of the coupling member is smaller than the angular width of the recess to allow this member to easily penetrate the recess. In addition, the coupling member is designed to have a large amount of play in the recess to allow this coupling member to move in the recess. Therefore, a relatively small impact may easily cause the coupling member to disengage from its recess. If this is the case, then when the spring is loaded against the teeth of the date ring or before loading this spring, due to the frictional force applied to the drum, the spring usually exhibits slight expansion, and the coupling member moves away from the side facing the radial driving side. In this case, the lateral wall of the drum applies a radial force to the coupling member, causing the coupling member to experience frictional force on this lateral wall. If the coupling element disengages from its recess when the spring is loaded against the teeth of the date ring, it slides along the inner lateral surface and no date jump will occur until at least the driving wheel has rotated one full turn and the coupling element re-enters its recess (this is the best-case scenario, but this results in the loss of the correct date display and misses the daily jump); or the frictional force is insufficient to cause the spring to stretch again, further increasing the frictional force until its coils touch the lateral wall, and a date jump occurs at an uncertain time. In the latter case, after the date jump, the spring will relax through the driving drum. If this situation occurs again, the next date change will no longer occur around midnight. If the coupling element experiences a certain sudden angular displacement along the lateral wall (which is possible), then this situation will repeat for at least several days, increasing the date at an uncertain and variable time. In any case, once the coupling member leaves its recess, the date driving mechanism will stop working for at least several days, and this event is very likely to occur for the mechanism as shown in the drawings of patent document EP 3828644.

[0005] The geometry of the coupling member relative to its recess (which allows the coupling member to have a large amount of play and a certain degree of mobility in the recess) gives rise to another problem. More specifically, when the spring is loaded, it will deform the coils of the spring and cause the coupling member to rotate around itself. This rotation will cause the coupling member to slide on the front lateral wall of the recess, such that when the spring is loaded, the point of application of the force of the spring on the drum finger decreases radially. Therefore, for a given spring loading level, the driving torque provided by the spring on the finger decreases proportionally with the decrease in the application of the force of the spring on the drum finger through the lever arm, which causes a problem because for a given contact point, the driving force of the finger on the teeth of the indicator decreases in the same proportion. Since a given driving torque is required for the indicator to jump, the spring will have to generate a greater force because the lever arm decreases during the loading of the spring, which has a negative impact on the performance of the watch movement with the spring loading the driving mechanism, and thus a greater torque must be provided. This also requires the spring to be dimensioned more robustly than necessary.

[0006] Finally, another problem of the mechanism under discussion is due to the fact that when the indicator is driven, the coils of the spring exert a radial force on the drum, which force is directed outwards in the region exactly opposite to the finger and thus substantially along the longitudinal direction of the oblong hole, which tends to move this finger away from the teeth of the ring. Therefore, the finger is more likely to pass over the teeth when the indicator is not being driven, especially when there is a small shock in this case. It should also be noted that this situation reduces the angular path by which the finger can drive the teeth by maintaining contact, such that the finger can pass over the teeth by an angular distance sufficient to ensure a date jump before it receives the driving torque, the date ring remaining stationary in the intermediate position or returning to its previous stable position after the finger has passed over the teeth. Moreover, for a given driving torque, reducing the lever arm for applying the driving force to the teeth requires an increase in the required driving force, which requires an increase in the force supplied by the spring and thus also an increase in its tension. Summary of the Invention

[0007] It is an object of the present invention to provide a mechanism for driving a jumping hour indicator which does not have the disadvantages of the above-mentioned prior art. The present invention also aims to provide a watch movement provided with an indicator and including a mechanism for driving this indicator to jump hours, which mechanism is efficient, which can be precise in each watch movement including such a mechanism, and whose operation is hardly disturbed by external stresses (such as shocks).

[0008] To this end, the present invention relates to a watch movement provided with an indicator and including a mechanism for driving this indicator to jump hours, the mechanism comprising: a wheel platform which defines a rotation axis; a rigid part which is arranged above the wheel platform and defines a driving finger for driving the indicator; and a spring which is formed by a first end, coils and a second end, the first end being attached to the wheel platform to rotate therewith and the second end being attached to the rigid part to rotate therewith at least each time the spring is loaded before the indicator jumps hours and during the driving of the indicator by the mechanism during this jump. The rigid part can rotate relative to the wheel platform and is rotatably guided about the rotation axis by a shaft passing through an opening in this rigid part, and this allows the driving finger to retract towards the rotation axis under the action of the radial component of the force applied to this driving finger. The mechanism is arranged such that the spring contracts when the spring is loaded in order to be able to cause the indicator to jump hours, and such that when the coils contract, the angular displacement of the second end of the spring and thus of the driving finger relative to the wheel platform and thus relative to the first end of the spring is limited by an angular stop which is attached to the wheel platform to rotate therewith.

[0009] In a preferred embodiment, the indicator and the mechanism are arranged such that, in normal operation, each jump of the indicator occurs after and thus corresponds to a determined angular distance (starting from the angular position where the spring is not angularly stressed): the angular displacement has been stopped by the angular stop after the spring loading before this jump has ended.

[0010] Due to the features of the present invention, in order to drive the indicator to jump, the coils of the spring contract over its entire length during the duration of the spring loading, so as to cause the indicator to jump and thus cause this indicator to increment the date. The coils of the spring are allowed to freely expand during the duration of this loading. First, for the dimensions of the spring and the characteristics of the material forming the spring, this is far less important than the expansion where only part of the coils are active in the final stage of the spring loading. Thereafter, the duration of the spring loading (until a given couple that causes the indicator to jump) depends only on the spring itself, in particular its stiffness. As long as the spring remains in its initial state and in particular has an invariant stiffness, the angular displacement between the two ends of the spring remains invariant from one loading to the next, such that the duration of the loading remains invariant for each loading of the spring and thus each jump occurs at a very precise given time. In addition, by contracting the spring, a constant radius can be obtained to apply the driving force of the finger to the indicator tooth against which the finger abuts, thereby optimizing this driving force and thus the driving torque required to cause the indicator to jump. Finally, due to the spring contraction, there is no need for a wall around the perimeter of the spring, the role of which is to limit the expansion of the coils of the spring and greatly increase the couple applied to the finger to cause the indicator to jump. Thus, although a drum finger is provided in a particular alternative embodiment, the present invention does not require a drum finger.

[0011] The features of the present invention also lie in the arrangement of the angular stop integral with the wheel platform, which limits the angular displacement of the second end of the spring relative to its first end to a predetermined invariant angular distance, thereby preventing the spring from leaving its elastic range and thus preventing the spring from deteriorating. In the above preferred embodiment, the angular stop is arranged such that, in normal operation, the indicator does not jump before a part integral with the second end of the spring or this second end abuts against the angular stop. Thus, whenever the spring is loaded, the drive mechanism has the same relative angular displacement between the drive finger and the wheel platform, this relative angular displacement being defined not by the stiffness of the spring but by the angular stop. In an advantageous alternative embodiment, the spring and the angular stop are part of the same component.

[0012] According to another advantageous embodiment, the rigid part is formed by a plate and an axial wall. The plate extends above the spring, and the opening is machined in the plate. The axial wall is arranged at the edge of this plate and slopes downward towards the wheel, and it can rest on the wheel. The axial wall and a part of the plate stacked thereon together form a driving finger, and the height of the driving finger extends at least from the lower side of the spring to the upper surface of the plate. The axial wall has a recess, and the recess has a lateral opening on the spring side. The second end of the spring is extended by a member for coupling with the rigid part, and this coupling member is configured such that when the spring is assembled with the rigid part, it can at least partially penetrate the recess and, once in place, allows the spring to apply a driving couple to the rigid part.

[0013] In an advantageous alternative embodiment, the coupling member and the recess are configured such that when the spring is loaded, the contact point or the contact zone strip of the recess does not change significantly, and the spring force is applied to this point or zone strip via the coupling member. The term "significantly" means that slight changes may occur during the short initial stage of spring loading. In particular, the force application point or zone strip of the spring on the rigid part via the coupling member does not move significantly towards the center of rotation, especially by the radial sliding of the coupling member or by its rotation around its own axis. For this purpose, in a specific alternative embodiment, the recess has a lateral surface that is obliquely oriented in the rotation direction of the wheel platform. In the spring-loaded configuration, the indicator is intended to be driven in this direction relative to the radial direction so as to pass through the center of this lateral surface, and the coupling member has a lateral side facing the lateral surface, and this lateral side is also obliquely inclined in the same direction as the lateral surface relative to the radial direction defined by the rotation axis, and at least partially abuts against this lateral surface when the spring is loaded and the indicator is driven during its next jump.

[0014] In a preferred embodiment, the coupling member and the recess are configured such that when the spring is loaded, the coupling member is substantially unable to rotate about itself in the rotational direction of the wheel platform. The term "substantially" means that slight rotation may occur during a short initial phase of spring loading. For this purpose, the coupling member advantageously has a heel for preventing the coupling member from rotating about itself in the rotational direction of the wheel platform. In the above - mentioned particular alternative embodiment, this feature, in combination with the configuration of the recess and the coupling member, effectively prevents any rotation of the coupling member about itself in the rotational direction of the wheel platform and thus prevents a change, in particular a reduction, in the force - application point of the spring on the rigid part equipped with the finger. Thus, for a given force applied by the spring, the driving torque of the finger remains constant. This property improves the efficiency of the drive mechanism because the conversion of the energy stored in the spring into the driving torque for driving the finger on the indicator is proportional to the force - application radius of the spring on the rigid part. Thus, for the driving force required to cause a given indicator to jump in time, the mechanism described herein does not need to compensate for lever losses by additional torque. It should be noted that the mechanical energy consumed by the drive mechanism from the timepiece movement has a direct impact on its performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The objects, advantages and features of the present invention will be described in more detail hereinafter with the aid of the drawings given by way of non - limiting example, in which:

[0016] - Figure 1 is a top view of a timepiece mechanism according to a first embodiment of the present invention, which is intended to drive a jumping - hour indicator, in particular in a semi - instantaneous jumping - hour manner;

[0017] - Figure 2 is Figure 1 the exploded perspective view of the timepiece mechanism in

[0018] - Figure 3 is Figure 1 the perspective view of the drum finger and the spring of the timepiece mechanism in

[0019] - Figure 4 is similar to Figure 3 the view of the drum finger and the spring of a timepiece mechanism according to a second embodiment of the present invention;

[0020] - Figure 5 is similar to Figure 3 the view of the drum finger and the spring of a timepiece mechanism according to a third embodiment of the present invention;

[0021] - Figures 6A to 6D shows the timepiece movement according to the first embodiment in four successive states that occur when the date ring is driven by the drive mechanism;

[0022] - Figure 7A andFigure 7B shown in two successive state portions respectively Figure 6A the timepiece movement in, these states occur when the date ring is rapidly driven by a conventional control member in the driving direction of the date ring;

[0023] - Figure 8A and Figure 8B shown in two successive state portions respectively Figure 6A the timepiece movement in, these states occur when the date ring is being driven, when the time display hand is driven in the counterclockwise direction and thus the wheel platform is driven in a direction opposite to the driving direction of this platform. DETAILED DESCRIPTION

[0024] Referring Figures 1 to 3 , a first preferred embodiment of a mechanism for driving an indicator to jump hours, particularly in a semi-instantaneous jump-hour manner, will be described; and referring Figures 6A to 8B , the operation of a timepiece movement according to the invention incorporating such a driving mechanism will be described. The jump-hour indicator is, for example, a minute indicator, an hour indicator, a date indicator, a day-of-the-week indicator or a month indicator.

[0025] The mechanism 6 for driving a jump-hour indicator, particularly the date ring 4, includes a wheel platform 8 having a rotational axis 22, a rigid portion 10 disposed on the wheel platform and defining a driving finger 12 for driving the indicator, and a spring 16 formed by a first end 17, a coil 18 and a second end 19. The rigid portion 10 is rotatable relative to the wheel platform 8 and is rotatably guided by a shaft passing through an opening 26 in this rigid portion about the rotational axis 22. In an alternative embodiment shown by way of non-limiting example, the opening defines an oblong hole (hereinafter referred to as oblong hole 26). Generally speaking, at least whenever the spring is loaded before the indicator jumps hours and when the indicator is driven by the mechanism during this jump hour, the first end 17 is attached to the wheel platform 8 to rotate therewith, and the second end 19 is attached to the rigid portion to rotate therewith. In a main alternative embodiment, the indicator is a date indicator, particularly the date ring. The first end 17 of the spring 16 is connected to a central portion 24, and the central portion 24 is attached to the wheel platform 8 to rotate therewith. Preferably, the spring and the central portion form the same part. The mechanism 6 includes a central hub 34 that defines a shaft passing through the oblong hole 26 in the rigid portion 10 and rotatably and translatably guiding this rigid portion relative to the wheel platform 8, and the wheel platform 8 and the central portion 24 are driven onto the central hub 34. The driving finger 12 has a substantially radial driving side 14 and an outer side 13, and the outer side 13 is arcuate and its slope gradually decreases with respect to a direction perpendicular to the radius when it approaches the driving side.

[0026] The rigid part 10 is formed by a plate 38 and an axial wall 40. The plate 38 extends above the spring, and an oblong hole 26 is machined in the plate 38. The axial wall 40 is arranged at the edge of this plate and slopes downward towards the wheel platform. In an alternative embodiment, it can rest on the wheel platform. A part of the axial wall 40 and a part of the plate 38 stacked thereon together form a drive finger 12. The height H of the drive finger 12 extends at least from the lower side of the spring 16 to the upper surface 39 of this plate. Thus, the rigid part 10 forms a drum finger that defines an internal space 11 in which the spring is arranged.

[0027] The axial wall 40 has a recess 42 at the drive finger 12. The recess 42 has a lateral opening on the spring 16 side. The second end 19 of the spring is extended by a member 20 for connection to the rigid part 10. This connection member 20 is configured such that it can at least partially penetrate the recess, and thus allows the spring to apply a driving couple to the rigid part 10. In particular, the connection member is rigid.

[0028] In the first embodiment, the connection member is configured to be able to pass through the lateral opening and at least partially penetrate the recess. Additionally, the recess 42 advantageously has a lateral surface 46 that is obliquely oriented in the rotation direction 50 of the wheel platform 8. In the configuration for loading the spring, the indicator 4 is intended to be driven in this direction relative to the radial direction, thus passing through the center of this lateral surface. The connection member 20 has a lateral side 48 facing this lateral surface, and the lateral side 48 is also obliquely inclined in the same direction as the lateral surface. And whenever the spring 16 is loaded to drive the jump indicator using the mechanism 6, it at least partially abuts against this lateral surface. This specific feature ensures that once the spring is tensioned during loading, the connection member is precisely held in a given driving position inside the recess. In other words, when the spring is loaded, the contact point or contact zone of the recess 42 does not change significantly, and the spring force is applied to this point or zone via the connection member 20. Only slight changes can occur during the short initial stage of spring loading.

[0029] Advantageously, the coupling member and the recess are configured such that when the spring is loaded, the coupling member 20 is substantially unable to rotate about its own axis in the direction of rotation of the wheel platform. During a short initial phase of spring loading, only slight rotation can occur. According to a particular feature, for this purpose, the coupling member 20 has a heel 52 which is intended to prevent the coupling member from rotating about its own axis in the direction of rotation 50 of the wheel platform (the direction of rotation intended for driving the indicator) once it is in place in the recess 42. This heel is extended by a contact surface 54 which abuts against the angular stop 28 at the end of spring loading, causing the indicator to jump. Preferably, in the angular extension of the coil 18 of the spring, the angular stop 28 is located between the first end 17 of the spring and the rigid ring 24 and is defined by the same part forming the rigid ring and the spring.

[0030] Once the coupling member 20 has been assembled to the drum finger 10, in the absence of any external stress and in particular without any shock, this coupling member always remains connected to the drum finger, regardless of the state of the mechanism, i.e., during the period when the teeth 5 of the indicator 4 do not interact with the drive finger 12, in the non-angularly stressed state of the spring, in the state where the spring contracts when it is loaded before the indicator jumps, when the indicator jumps and also when the spring is stressed and extended, and in particular when the wheel platform 8 rotates in a direction opposite to the established direction for driving the indicator 4 in order to correct the time in the counterclockwise direction. In short, during normal operation of the timepiece movement, the coupling member 20 remains connected to the drum finger as expected (i.e., in place in the recess 42) and is thus integral with the drum finger.

[0031] It is noted that the mechanism 6 is arranged such that if the coupling member 20 happens to come out of the recess 42 during an impact, regardless of the state of the mechanism before such impact, this coupling member cannot move beyond this recess in the direction of rotation 50 of the wheel platform 8. If the impact generates a force on the coupling member that could cause this coupling member to leave its recess (a situation that is highly unlikely to occur), the spring is in a state that allows the coupling member to return to the recess. The rigid part and the coupling member are arranged such that if the coupling member 20 is located upstream of the recess 42 with respect to the driving direction of the wheel platform, after the drive finger 12 has abutted against the tooth 5a of the indicator 4, for the next scheduled jump and before the next indicator jump occurs, the spring is driven by the wheel platform to return the coupling member to the recess so that the jump of this indicator is not missed and the indicator thus continues to display the correct information.

[0032] In an advantageous alternative embodiment, the recess 42 has a minimum dimension on its open side, which minimum dimension is slightly smaller than the maximum dimension of the coupling member perpendicular to the radial direction with respect to the axis of rotation 22 of the spring in the angularly relaxed state (coinciding with the central axis of the rigid ring 24). More generally, the coupling member and the recess are arranged such that the coupling member cannot be disengaged from the recess by undergoing at least one translation with respect to the rigid part, i.e., without undergoing at least one rotation about its own axis (rotation about its geometric center about an axis parallel to the axis of rotation 22). Thus, for the coupling member to enter the recess through the lateral opening, the coupling member must rotate slightly about its own axis. This particular feature ensures that once the coupling member has been correctly inserted into the recess 42 and is thus in the proper position, the risk of its disengagement from the recess is very small, although in exceptional cases, in the event of a particular shock, this is not impossible.

[0033] Figure 4 Shows a mechanism 6A for driving the hour jump of an indicator according to a second embodiment of the present invention. This mechanism 6A differs substantially from the mechanism of the first embodiment in that the coupling member 20A has a different shape, and the profile of the recess 42A designed to receive the coupling member is also different. The recess 42A arranged in the lateral wall 40A of the drum finger 10A has an overall triangular shape and gradually leads to the internal space 11 of the drum finger 10A in which the spring is arranged. The shape of the part of the coupling member 20A inserted into the recess through the lateral opening substantially corresponds to the shape of the recess. This configuration allows the coupling member to be easily inserted into the recess, but would a priori allow this member to disengage in the event of a shock, even if the recess is designed to be relatively deep, without providing additional means to prevent this. The means provided here for best maintaining the coupling member in the recess, especially in the event of a shock, are the shape of the internal part of the coupling member and the shape of the central part 24 and the relative arrangement of this internal part with respect to this central part. In the most likely case, the internal part of the coupling member abuts against the central part 24 before the coupling member is completely disengaged from the recess. In addition, the coupling member 20A is substantially aligned with the longitudinal axis of the oblong hole 26 such that when it undergoes a substantially radial acceleration and especially along the longitudinal axis of the recess 42A towards the axis of rotation, the more rigid drum finger 10A undergoes the same radial movement in the same direction, which tends to keep the coupling member in the recess.

[0034] In this second embodiment, once inserted into its recess 42A, the coupling member 20A is held in place in its recess by the radial force exerted by the spring on the lateral wall 40A of the drum finger 10A. During rapid date change or during counterclockwise time correction through midnight, this radial force increases because the drive finger retracts towards the axis of rotation 22 via the radial displacement of the drum finger, such that even when the spring 16 is forced to stretch in these cases, the coupling member generally remains in the recess because the drum finger rotates relative to the wheel platform 8 in a direction opposite to the relative rotation direction of this drum finger that occurs when the date ring is driven by the mechanism 6A. Preferably, as in the first embodiment, the recess 42A advantageously has a lateral surface 46A that is obliquely oriented in the normal rotation direction of the wheel platform, and in the spring-loaded configuration, the indicator is intended to be driven relative to the radial direction in this direction, thereby passing through the center of this lateral surface, and the coupling member 20A has a lateral side 48A facing this lateral surface, and the lateral side 48A is also obliquely inclined relative to the axis of rotation 22 in the same direction as the lateral surface, and at least partially abuts against this lateral surface whenever the indicator is driven by the mechanism. The lateral surface and the lateral side are relatively long. This particular feature ensures that once the spring 16 contracts, the coupling member is firmly held in the recess. In particular, when the spring is loaded, the contact point or contact zone of the recess does not change, and the spring force is applied via the coupling member at this point or zone. In addition, when the spring is loaded, the coupling member 20A cannot rotate about itself in the rotation direction of the wheel platform.

[0035] Figure 5 Fig. 6B shows a mechanism 6B for driving the hour indicator jump according to a third embodiment of the present invention. First, this embodiment differs from the previous embodiments in that the coupling member 20B is inserted into a recess 42B from which it cannot escape via a lateral opening. The inevitable consequence of this feature involves assembling the spring 16 to a rigid part 60, where in this case the coupling part 20B must be axially inserted into the recess 42B. The coupling member has a heel 52 and a contact surface 54 that is intended to abut against the angular stop 28 when spring loading is complete and before the indicator jumps. Second, the mechanism 6B differs from the previous embodiments in that the rigid part 60 does not form a drum finger, and this rigid part is formed by an elongated plate 62 that has an oblong hole 26 at its first end and a lateral wall 64 at its second end, and the lateral wall 64 descends (or ascends depending on the spatial position of this part) from this elongated plate, and its main part forms the drive finger 12. It should be noted that the central part 24B to which the first end 17 of the spring 16 is connected is not driven onto a central hub (not shown), but has an internal projection 66 that fits into a recess in the central hub, thereby being attached to the wheel platform to rotate with it.

[0036] Subsequently, the reference returns to the first embodiment (which is preferred) in order to use Figures 6A to 8B to show in more detail the operation of the timepiece movement 2 and in particular of the mechanism 6 for driving the date ring 4. It should be noted that in Figures 6A to 8B the plate 38 of the drum finger 10 is not shown in order to better illustrate the elements located in the internal space 11 of the drum finger.

[0037] The rigid part 10 can rotate relative to the wheel platform 8 and is rotatably guided about the axis of rotation 22 by an axis formed by the hub 34 passing through the oblong hole 26, which allows the driving finger to retract towards the axis of rotation under the action of the interaction between the teeth 5 of the indicator 4 and the outer face 13, which generates a progressive radial force. This retraction helps to allow the driving finger 12 to retract during the rapid correction of the date ring 4 in the direction of rotation 30 of this indicator (this indicator being intended to be the normal direction of rotation driven each time by the mechanism 6), or during the time correction in the counterclockwise direction and when the finger abuts against the upper face of the teeth 5 in the case of incorrect guidance of the indicator. The mechanism is arranged such that the spring 16 contracts when this spring is loaded in order to be able to produce a jump hour, in particular a semi-instantaneous jump hour of the indicator. Furthermore, when the coil 18 contracts due to spring loading, the angular displacement of the second end 19 of the spring and thus of the driving finger 12 relative to the wheel platform 8 and thus relative to the first end 17 of the spring is limited by an angular stop 28 attached to the wheel platform 8 to rotate therewith. Preferably, the indicator and the mechanism are arranged such that, in normal operation, the jump hour of the indicator occurs after and thus corresponds to an angular distance α determined by this angular stop: the angular displacement has been stopped by the angular stop 28 after the end of the spring loading before this jump hour. It should be noted that in an advantageous embodiment, in normal operation, the jump hour of the indicator occurs before the angular displacement has been stopped by the angular stop 28. In this case, the angular stop is a spring protection stop.

[0038] In a general embodiment, the drive mechanism does not have any angular stops. During the loading cycle, the spring contracts and the coils of this spring remain freely extended between the two ends of the spring.

[0039] Figures 6A to 6D Shows four successive states of the mechanism 6 for driving the date ring 4 to jump hour, in particular a semi-instantaneous jump hour. Figures 6A to 6DShows the mechanism 6 and the date ring 4 at the following moments when this ring is driven to change to the next date at midnight: when the driving finger 12 contacts the tooth 5a of the ring 4 and the spring 16 is substantially angularly relaxed (i.e., not angularly stressed); after the end of the loading of the spring 16, when the contact surface 54 of the coupling member 20 abuts against the angular stop 28 after having undergone an angular displacement α relative to the wheel platform 8; during the date jump generated by the mechanical energy stored in the retraction spring being applied to this drum finger; at the end of the jump, when the date ring has substantially reached its next stable position.

[0040] It should be noted that in order to prevent the tooth 5a of the indicator 4 from passing above or below the driving finger 12 when the indicator is driven, it is provided that the height (including the play) between the wheel platform 8 and the lower side of the tooth part 5 is constantly maintained between the lower height and the upper height (including the play) of the driving finger from the wheel platform. For this purpose, in an advantageous alternative embodiment, the lower height of this finger is less than the thickness of the teeth of the tooth part 5. Preferably, in a watch incorporating the watch movement 2, the upper height of the finger and the distance between the dial covering the driving mechanism and the indicator are also designed to be less than the thickness of the teeth of the tooth part 5. The large height of the finger 12 (which can at least rise from the lower side of the spring 16 above the plate 38 defining the upper surface of the mechanism 6) makes it easy to prevent the tooth 5a from passing above or below the finger 12.

[0041] Figure 7A and Figure 7B Shows the behavior of the mechanism 6 during the rapid correction of the date ring 4, by means of a control member that the user can operate in a conventional manner. In the evening, the wheel platform 8 and the drum finger 10 are initially, for example, in Figure 7A the configuration shown in, such that the finger 12 is located between the tooth 5a and the tooth 5b preceding it in the direction of rotation 30, such that the finger 12 is in the path of the tooth 5b of the indicator. The ring 4 is intended to advance rapidly in the direction of rotation 30 in a single direction in which the date ring is driven. As Figure 7BAs shown, when the ring 4 rotates, the tooth 5b of the tooth part 5 contacts the arcuate outer side surface 13 of the finger 12, and then applies a progressive radial force on this finger. Due to the presence of the long oval hole 26 (whose longitudinal axis is substantially aligned with the finger), this force causes the drum finger 10 to move, such that this finger retracts towards the central hub part and thus towards the axis of rotation 22. Consequently, the finger 12 retracts, thereby allowing the tooth 5b to follow the outer side surface 13 of the finger until this tooth projects angularly beyond the finger. During the radial displacement of the drum finger, the spring contracts radially, and the coupling member 20 moves closer to the central hub part and the central part 24, which has an enlarged cavity that is intended to receive the inner part of the coupling member 20 when the coupling member 20 approaches this central part during the quick correction date ring. It should be noted that the spring 16, more precisely its coils 18, also stretch during the quick correction date ring, while the spring is subjected to a radial stress towards the axis of rotation of the wheel platform.

[0042] Figure 8A and Figure 8B shows the behavior of the mechanism 6 during the correction of the time displayed by the timepiece mechanism, which causes the wheel platform 8 to rotate counterclockwise to midnight. In this case, the date ring 5 remains stationary at its stable position during the correction of the time. The successive states of the mechanism 6 are similar to the successive states described above that occur during the quick correction of the date display. When the wheel platform 8, and thus the drum finger 10, rotates in a direction opposite to the normal rotation direction 50 (corresponding to the clockwise direction of the time display), the arcuate outer side surface 13 of the finger 12 abuts against the tooth 5a of the tooth part 5 ( Figure 8A ), and the drum finger continues to rotate, but more slowly than the wheel platform, while driving the finger to move radially towards the axis of rotation 22, such that this finger retracts, while the stationary tooth extends along the outer side surface 13 of this finger. Once again, the spring 16 is forced to stretch during this correction.

[0043] The mechanism 6 is configured to prevent jamming during the quick date correction or the counterclockwise time correction.

[0044] The invention also relates to a watch comprising a timepiece movement 2 according to the invention, which movement is incorporated into a watch case, which watch case also incorporates a dial that is arranged to allow the display of data items that change over time by jumping, in particular the date display.

Claims

1. A watch movement (2), the watch movement being provided with an indicator (4) and comprising a mechanism (6, 6A, 6B) for driving the indicator to jump time, the mechanism comprising: A wheel platform (8) defining an axis of rotation (22); a rigid part (10, 10A, 60) arranged above the wheel platform and defining a drive finger (12) for driving the indicator; and a spring (16) formed by a first end (17), a coil (18) and a second end (19), the first end being attached to the wheel platform for rotation therewith and the second end being attached to the rigid part for rotation therewith, the rigid part being rotatable relative to the wheel platform and being driven by a spring passing through the ... the coil (18) and the second end (19), the first end being attached to the wheel platform for rotation therewith and the second end being attached to the rigid part for rotation therewith, the rigid part being rotatable relative to the wheel platform and being driven by a spring passing through the first end (17), the coil (18) and the second end (19), the first end being attached to the wheel platform for rotation The axis of the opening (26) in the rigid part is rotatably guided about the rotation axis (22), and this allows the drive finger to be retracted towards the rotation axis under the action of the radial component of the force exerted on this drive finger; characterized in that the mechanism is arranged so that the spring (16) contracts when this spring is loaded so as to be able to cause the indicator to jump subsequently; and wherein when the coil contracts, the angular displacement of the second end of the spring and therefore the drive finger (12) relative to the wheel platform and therefore relative to the first end of the spring is limited by an angular stop (28) attached to the wheel platform (8) so as to rotate therewith.

2. The watch movement according to claim 1, characterized in that: The indicator and the mechanism are arranged so that, in normal operation, a jump by the indicator occurs after the angular displacement has been stopped by the angular stop after the spring loading preceding this jump has ended and therefore corresponds to a determined angular distance (α).

3. The watch movement according to claim 1 or 2, characterized in that: The first end (17) of the spring (16) is connected to a central portion (24, 24B) which is attached to the wheel platform (8) for rotation therewith.

4. The watch movement according to claim 3, characterized in that: The mechanism (6) comprises a central hub (34) defining an axis passing through the opening (26) in the rigid part (10, 10A, 60) and guiding this rigid part rotatably and translationally, wherein the wheel platform (8) and the central part (24) are attached to the central hub so as to rotate therewith.

5. A timepiece movement according to any one of the preceding claims, characterised in that The rigid portion is formed by a plate (38, 62) extending above the spring and in which the opening (26) is machined, and an axial wall (40, 40A, 64) arranged at the edge of this plate and inclined downwardly towards the wheel platform, at least a portion of the axial wall and a portion of the plate stacked thereon together forming a drive finger, the height (H) of the drive finger extending at least from the lower side of the spring to the upper surface (39) of the plate.

6. The watch movement according to claim 5, characterized in that: The rigid portion (10, 10A) forms a drum finger defining an internal space (11) in which the spring (16) is located.

7. The watch movement according to claim 5 or 6, characterized in that: The axial wall (40, 40A) has a recess (42, 42A) having a lateral opening on the side of the spring (16); and wherein the second end (19) of the spring is extended by a member for coupling with the rigid part (10), this coupling member (20, 20A) being configured to be able to at least partially penetrate the recess through the lateral opening and thus allow the spring to apply a force couple to the rigid part (10, 10A) and thus allow the drive finger to drive the indicator.

8. The watch movement according to claim 7, characterized in that: The recess (42, 42A) and the coupling member (20, 20A) are configured so that when the spring is loaded, the contact point or contact zone of the recess does not change significantly, and the spring force is applied to the point or zone via the coupling member.

9. The watch movement according to claim 7 or 8, characterized in that: The recess (42, 42A) and the coupling member (20, 20A) are configured such that when the spring is loaded, the coupling member is substantially unable to rotate about itself in the direction of rotation of the wheel platform.

10. A timepiece movement according to any one of claims 7 to 9, characterized in that The recess (42, 42A) has a lateral surface (46, 46A) which is oriented obliquely in the direction of rotation (50) of the wheel platform (8), in which direction the indicator is intended to be driven relative to the radial direction so as to pass through the center of this lateral surface in the spring-loaded configuration, and the coupling member (20, 20A) has a lateral side (48, 48A) facing the lateral surface, which lateral side (48, 48A) is also inclined obliquely in the same direction as the lateral surface (46, 46A) relative to the rotation axis and at least partially abuts against this lateral surface when the spring is loaded and when the indicator is driven for the next jump.

11. A timepiece movement according to any one of claims 7 to 10, characterized in that The coupling member (20) has a rear heel portion (52) for preventing the coupling member from rotating about itself in the rotation direction (50) of the wheel platform.

12. A timepiece movement according to any one of the preceding claims, characterised in that The indicator is a minute indicator, an hour indicator, a date indicator, a day indicator or a month indicator, and the indicator comprises a toothed portion.

13. The watch movement according to claim 12, characterized in that: The indicator (4) is a date ring comprising an internal toothing (5).

14. A table, characterized in that It comprises a timepiece movement (2) according to any one of the preceding claims.

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