Horological movement provided with mechanism for driving jumping indicator and wrist watch including the same

Abstract

To provide a horological movement provided with an indicator and including a mechanism for driving the indicator in jumps.SOLUTION: The horological movement is provided with an indicator 4 and includes a mechanism 6 for driving the indicator in jumps. The mechanism includes a wheel platform 8, a rigid part 10 defining a driving finger 12, and a spring 16. The spring has a first end attached to the wheel platform for rotation therewith and a second end attached to the rigid part for rotation therewith. The mechanism is arranged so that the spring contracts when the spring is loaded to generate a jump by the indicator. An angular displacement of the driving finger with respect to the wheel platform is then limited, when the spring is contracted, by an angular stop 28 attached to the wheel platform for rotation therewith.SELECTED DRAWING: Figure 6A

Description

Technical Field

[0001] The present invention relates to a timepiece movement provided with an indicator and including a mechanism for jump-driving this indicator, and further relates to a wristwatch incorporating such a timepiece movement provided with such a mechanism. Specifically, the indicator is a date indicator.

Background Art

[0002] Patent Document 1 describes a mechanism for driving a jump indicator. This mechanism advantageously includes a rigid drum finger that is rotatably and translationally guided by a hub passing through an oval hole of a drum, and a spring disposed on this drum finger, the spring connecting the drum finger to a wheel platform, thereby overcoming the technical problems of the prior art.

[0003] This drive mechanism has a number of drawbacks. First, the spring expands when the date ring is driven, and the coils of the spring are intended to contact the inner wall of the drum when the spring is loaded, so the expansion of the spring is limited and reaching the plastic region of the spring is prevented. As a result, a sudden decrease in the effective length of the spring is brought about. Considering the manufacturing tolerances of various components, the load application time of the drive mechanism can vary. This is because the time when the spring comes into contact with the inner wall of the drum varies for each load application, and the angular position of the contact zone also varies. This results in inaccuracy in the time at which the ring triggers the transition to the next date. Another problem arises from the fact that the driving force is transmitted to the finger via the coils of the spring. That is, the spring needs to have sufficient rigidity / hardness over its entire length, specifically, over the portion located between the contact zone with the wall of the drum and the connecting member connecting this drum disposed at the second end of the spring, and this portion ultimately needs to withstand the entire additional torque generated from the moment of contact until the moment the indicator jumps.

[0004] The figure of Cited Document 1 shows that the connecting member of the spring is arranged in a shallow recess where this member can easily appear. The two side surfaces of this recess are parallel in the radial direction passing through the middle of the recess, the connecting member has two radial flanks, and the angular width of the connecting member is smaller than the angular width of the recess so that this member can easily penetrate into the recess. Furthermore, the connecting member is intended to have a large play in the recess so that this connecting member can move in the recess. That is, with a relatively small impact, the connecting member can easily come off its recess. In this case, when the spring abuts against the teeth of the date ring and receives a load action, or at any time before this spring receives a load action, the spring typically shows a slight expansion due to the friction exerted on the drum, but the connecting member slips out from the side surface of the finger radial drive flank. In this situation, the side wall of the drum exerts a radial force on the connecting member, and the connecting member receives the frictional force with this side wall. When the spring abutting against the teeth of the date ring receives a load, if the connecting element comes off the recess, then thereafter, the connecting element slides along the inner side surface, and no date jump occurs until at least the drive wheel rotates once and the connecting element enters the recess again (the best scenario, but still resulting in the loss of the correct date display that has missed the date jump), or until the frictional force increases to such an extent that the spring expands again by the frictional force and its coil contacts the side wall and a date jump occurs at an uncertain time. In the latter case, after the date jump, the spring is loosened by the drive of the drum. When this situation recurs, the next date change will no longer be made around midnight. If the connecting element undergoes a predetermined sudden angular displacement along the side wall (which is possible), this situation will be repeated with an uncertain and variable number of date increments for at least several days. In any case, the date drive mechanism ceases to function for at least several days as soon as the connecting member comes off its recess. This event is very likely to occur in the case of the mechanism shown in the figure of Patent Document 1.

[0005] The geometry of the connecting member relative to the recess, which allows for a large amount of play and a predetermined mobility of the connecting member in the recess, causes other problems. Specifically, when a load is applied to the spring, the coils of the spring deform and the connecting member is rotated about its own axis. This rotation causes the connecting member to slide relative to the front wall of the recess, so that as the load on the spring increases, the point of application of the force from the spring to the drum finger is reduced radially. That is, for a given spring load application level, the driving torque exerted by the spring on the finger decreases in proportion to the reduction in the leverage of the force from the spring to the finger. This causes a problem. This is because the driving force of the finger on the teeth of the indicator decreases at the same rate for a given contact point. Since a given driving torque is required to jump the indicator, the spring must generate a greater force by the amount by which the lever arm decreases while the spring is under load. This adversely affects the performance of the timepiece movement, which must be given a large torque by loading the spring of the drive mechanism. This further requires the spring to be made of unnecessarily robust dimensions.

[0006] Finally, another problem with the mechanism of the issue arises from the fact that when the indicator is driven, the coils of the spring exert a radial force on the drum that is directed outward in the area diametrically opposite the finger, and thus substantially in the longitudinal direction of the oblong hole. This tends to move this finger away from the tooth portion of the ring. Therefore, especially in the event of a small impact in such a situation, the finger is likely to pass through the teeth without the indicator being driven. It should also be noted that in such a situation, since the angular path by which the finger can drive the teeth by maintaining contact is reduced, it becomes possible for the finger to pass through the teeth before receiving the driving torque over an angular distance sufficient to ensure a date jump. The date ring remains stationary in the intermediate position or returns to the previous stable position as soon as the finger passes through the teeth. Furthermore, to reduce the lever arm applying the driving force to the teeth, it is necessary to increase the required driving force for a given driving torque. This in turn requires increasing the force exerted by the spring and thus its tension.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

[0008] An object of the present invention is to provide a mechanism for driving a jumping indicator, which mechanism does not have the drawbacks of the prior art described above. The present invention further aims to provide a timepiece movement provided with an indicator and including a mechanism for jump-driving this indicator. This mechanism is efficient and can be accurate in each timepiece movement including such a mechanism. Its operation is hardly or not at all hindered by external stresses such as impacts.

[0009] For this purpose, the present invention relates to a timepiece movement provided with an indicator, the timepiece movement including a mechanism for jump-driving the indicator. The mechanism includes a wheel platform defining a rotation axis, a rigid part disposed on the wheel platform and defining a drive finger for driving the indicator, and a spring formed by a first end, a coil, and a second end. The first end is attached to the wheel platform so as to rotate therewith, and the second end is attached to the rigid part so as to rotate therewith at least between the loading of the spring prior to the jump by the indicator and the driving of the indicator by the mechanism during this jump. The rigid part is rotatable relative to the wheel platform and is rotatably guided about the rotation axis by a shaft passing through an opening in the rigid part, whereby the drive finger is allowed to retreat towards the rotation axis under the action of the radial component of the force exerted on the drive finger. The mechanism is arranged such that the spring contracts when loaded, so as to be able to jump the indicator, and such that when the coil contracts, the angular displacement of the second end of the spring and thus of the drive finger relative to the wheel platform and thus to the first end of the spring is limited by an angular stop attached thereto for rotation therewith.

[0010] In a preferred embodiment, the indicator and the mechanism are arranged such that each jump by the indicator occurs after the angular displacement has been stopped by the angular stop when, in normal operation, the loading of the spring preceding this jump has once ended and thus corresponds to a determined angular distance (from an angular position where the spring is not under angular stress).

[0011] Due to this feature of the present invention, in order to jump-drive the indicator, the coil of the spring contracts over its entire length during the loading action on the spring, thereby jumping the indicator and thus incrementing this indicator. The coil of the spring is left free to expand during the loading action. First, this is not so important for the dimensions of the spring and the characteristics of the material forming it compared to the expansion where only a part of the coil becomes active at the end stage of the loading action on the spring. Thereafter, the duration of the loading action on the spring until a given couple for jumping the indicator is reached depends only on the spring itself, particularly its stiffness. As long as the spring remains in its initial state and particularly its stiffness does not change, the angular displacement between the two ends of the spring remains unchanged for each loading action, so the duration of the loading action remains unchanged for each loading action on the spring, and thus each jump occurs at a very precise given time. Furthermore, by contracting the spring, a constant radius can be obtained for applying the driving force of the finger to the teeth of the indicator with which the finger abuts, so this driving force and thus the driving torque required to jump the indicator can be optimized. Finally, thanks to the contraction of the spring, the wall around the outer periphery of the spring becomes unnecessary. The function of that wall is to limit the expansion of the coil of the spring and to significantly increase the couple applied to the finger to jump the indicator. That is, the present invention does not require a drum finger, although in a particular alternative embodiment, a drum finger is provided.

[0012] The present invention also features arranging an angle stop integral with the wheel platform, which limits the angular displacement of the second end relative to the first end of the spring to a predetermined constant angular distance, thereby preventing the spring from departing from its elastic range and thus preventing spring degradation. In the preferred embodiment described above, the angle stop is arranged such that, in normal operation, the part integral with the second end of the spring or the indicator does not jump before the second end comes into contact with the angle stop. That is, each time the spring is loaded, the drive mechanism has the same relative angular displacement between the drive finger and the wheel platform, which is defined by the angle stop rather than by the spring stiffness. In an advantageous alternative embodiment, the spring and the angle stop are part of the same component.

[0013] According to another advantageous embodiment, the rigid part is a plate extending above the spring, which is a plate with the opening machined, and an axial wall arranged at the edge of this plate, which is inclined towards the wheel and on which an axial wall can be placed. The axial wall and a part of the plate laminated thereon together form a drive finger, which has a height extending at least from the lower side of the spring to the upper surface of the plate. The axial wall has a recess with a lateral opening on the spring side. The second end of the spring is extended by a member connecting to the rigid part, and this connecting member is configured to be able to penetrate at least partially into the recess when the spring is assembled to the rigid part, and once placed in a fixed position, the spring is allowed to apply a driving couple to the rigid part.

[0014] In an advantageous alternative embodiment, the connecting member and the recess are configured such that the contact point or contact zone of the recess where the spring force acts via the connecting member does not substantially change when the spring is loaded. The term "substantially" indicates that minor variations may occur in the short initial stage of the spring loading action. In particular, the force of the spring on the rigid part via the connecting member The point or zone to which it is added does not move substantially towards the center of rotation, particularly by radial sliding of the connecting member or rotation about itself. For this purpose, in a particular alternative embodiment, the recess has a lateral surface that is obliquely oriented in the rotational direction of the wheel platform. The indicator is intended to be driven in its rotational direction and is intended to be driven radially through the center of this lateral surface in a spring-loaded configuration. The connecting member has a lateral flank that faces this lateral surface, and this lateral flank is also obliquely inclined in the same direction as this lateral surface with respect to the radial direction defined by the axis of rotation and at least partially abuts this lateral surface when the spring is loaded and the indicator is driven during its next jump.

[0015] In a preferred embodiment, the connecting member and the recess are configured such that when the spring is under load, the connecting member cannot substantially rotate about itself in the rotational direction of the wheel platform. The term "substantially" indicates that a slight rotation may occur during the short initial stage of the spring load action. For this purpose, the connecting member preferably has a rear heel that blocks the rotation of the connecting member about itself in the rotational direction of the wheel platform. In the specific alternative embodiment described above, this feature, combined with the configuration of the recess and the connecting member, is effective in preventing the rotation of the connecting member about itself in the rotational direction of the wheel platform, and thus in preventing the point of application of the spring force to the rigid part with the finger attached from changing, particularly from decreasing. That is, the driving torque of the finger remains constant for a given force applied by the spring. This characteristic improves the efficiency of the drive mechanism. This is because converting the energy stored in the spring into the driving torque that drives the finger on the indicator is directly proportional to the radius at which the spring force is applied to the rigid part. Therefore, for a given driving force required to jump an indicator, the mechanism described here does not need to compensate for the loss of the lever action with additional torque. It should be noted that the mechanical energy consumed by the drive mechanism is taken from the watch movement and directly affects its performance.

Brief Description of the Drawings

[0016] The objects, advantages and features of the present invention will be described in detail below with the aid of the accompanying drawings given as non-limiting examples.

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6A

Figure 6B

Figure 6C

Figure 6D

Figure 7A

Figure 7B

Figure 8A

Figure 8B

DETAILED DESCRIPTION OF THE INVENTION

[0018] Referring to FIGS. 1 to 3, a first preferred embodiment of a mechanism for driving an indicator in a jump, particularly a half-instantaneous jump, will be described, and referring to FIGS. 6A to 8B, the operation of a clock movement according to the present invention incorporating such a driving mechanism will be described. The jump indicator is, for example, a minute indicator, an hour indicator, a date indicator, a day indicator, a month indicator.

[0019] A mechanism 6 for driving a jump indicator, particularly a date ring 4, includes a wheel platform 8 having a rotation axis 22, a rigid part 10 disposed on the wheel platform, the rigid part 10 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 rigid part 10 is rotatable relative to the wheel platform 8 and is rotatably guided around the rotation axis 22 by a shaft passing through an opening 26 in the rigid part. In an alternative embodiment shown as a non-limiting example, the opening defines an oval hole (hereinafter referred to as the oval hole 26). Typically, at least each time the spring is loaded before a jump by the indicator and when the indicator is driven by the mechanism during the jump, the first end 17 is attached so as to rotate together with the wheel platform 8, and the second end 19 is attached so as to rotate together with the rigid part. In a main alternative embodiment, the indicator is a date indicator, specifically a date ring. The first end 17 of the spring 16 is connected to a central portion 24 attached so as to rotate together with the wheel platform 8. Preferably, the spring and the central portion form one and the same part. The mechanism 6 includes a central hub 34 defining a shaft passing through the oval hole 26 in the rigid part 10. The central hub 34 rotatably and translationally guides the rigid part relative to the wheel platform 8, and the rigid part 10 and the central part 24 are driven towards the central hub 34. The drive finger 12 has a substantially radial drive flange 14 and an arched outer flange 13, the outer flange 13 being inclined such that the inclination gradually decreases in a direction perpendicular to the radius as it approaches the drive flange.

[0020] The rigid component 10 is formed by a plate 38 and an axial wall 40 disposed at the edge of this plate. The plate 38 extends over the spring, and an oblong hole 26 is machined in the plate 38. The axial wall 40 is inclined toward the wheel platform, and in one alternative embodiment, the axial wall 40 can be placed on the wheel platform. A part of the axial wall 40 and a part of the plate 38 laminated thereon jointly form the drive finger 12. This drive finger 12 has a height H extending from at least below the spring 16 to the upper surface 39 of the plate. The rigid component 10 thus forms a drum finger that defines an internal space 11 in which the spring is disposed.

[0021] The axial wall 40 has a recess 42 in the drive finger 12. The recess 42 has a lateral opening on the side of the spring 16. The second end 19 of the spring is extended by a member 20 that connects to the rigid component 10, and this connecting member 20 is configured to be able to penetrate at least partially into the recess, so that the spring is allowed to apply a driving couple to the rigid component 10. In particular, the connecting member is highly rigid.

[0022] In the first embodiment, the connecting member is configured to be able to at least partially penetrate into the recess through the side opening. Further, the recess 42 preferably has a side surface 46 that is obliquely oriented in the rotational direction 50 of the wheel platform 8. In a configuration where a spring is loaded, the indicator 4 is intended to be driven in a radial direction that penetrates the center of the side surface in this rotational direction. The connecting member 20 has a side flange 48 that faces the side surface, and the side flange 48 is also obliquely inclined in the same direction as the side surface. Each time the spring 16 is loaded to drive the jump indicator using the mechanism 6, it at least partially abuts against the side surface. Due to this specific feature, while the spring is under tension during the load application, the connecting member is accurately held in a given driving position within the recess. In other words, the contact point or contact zone of the recess 42 where the spring force is exerted via the connecting member 20 does not change when the spring is loaded. In the short initial stage of the spring loading action, only slight fluctuations occur.

[0023] Advantageously, the connecting member and the recess are configured such that when the spring is loaded, the connecting member cannot substantially rotate about itself in the rotational direction of the wheel platform. In the short initial stage of the spring loading action, only slight rotation occurs. According to a specific feature, for this purpose, once the connecting member 20 is positioned in the recess 42, it has a rear heel 52 that is intended to prevent the rotation of the connecting member about itself in the rotational direction 50 of the wheel platform (the rotational direction intended for driving the indicator). This rear heel is extended by a contact surface 54 and abuts against the angular stop 28 when the loading action on the spring ends, causing the indicator to jump. Preferably, the angular stop 28 is arranged on the angular extension line of the coil 18 of the spring, between the first end 17 of the spring and the rigid ring 24, and is defined by the same part that forms the rigid ring and the spring.

[0024] Once the connecting member 20 is assembled to the drum finger 10, without external stress, especially without impact, this connecting member, regardless of the state of the mechanism, i.e., even during the period when there is no interaction between the tooth portion 5 of the indicator 4 and the drive finger 12, and even when the spring is under non-angular stress, when the spring is loaded before the indicator jumps, when the indicator jumps, and even when the spring expands and is stressed, especially when the wheel platform 8 is rotated in a direction opposite to the intended direction for driving the indicator 4 to correct the time in the counterclockwise direction, the connecting member always remains connected to the drum finger. As a conclusion, during the normal operation of the clock movement, the connecting member 20 remains connected to the drum finger as intended, i.e., remains located in the recess 42, and thus remains integrated with the drum finger.

[0025] It should be noted that the mechanism 6 is arranged such that even if the connecting member 20 comes out of the recess 42 during an impact, this connecting member cannot move beyond this recess in the rotation direction 50 of the wheel platform 8, regardless of the state of the mechanism before such an impact. In the event of an impact that generates a force on the connecting member that causes the connecting member to move away from its recess (although the probability is extremely low), the spring is in a state where it can return the connecting member to the recess. When the connecting member 20 is arranged upstream of the recess 42 with respect to the direction in which the wheel platform is driven, the rigid parts and the connecting member are arranged to return the connecting member to the recess after the spring is driven by the wheel platform and before the next indicator jump occurs, such that the drive finger 12 contacts the tooth 5a of the indicator 4 to perform the next scheduled jump. As a result, the jump by this indicator is not lost, and the indicator continues to display correct information.

[0026] In an advantageous alternative embodiment, the recess 42 has a minimum dimension at its opening side that is slightly smaller than the maximum dimension of the connecting member perpendicular to the radial direction with respect to the rotation axis 22 of the spring (coinciding with the central axis of the rigid ring 24) in the angle-relaxed state. Further typically, the connecting member and the recess are arranged such that the connecting member cannot exit the recess without 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 rotation axis 22). In order to enter the recess through the side opening, the connecting member has to rotate slightly about itself. Due to this particular feature, once the connecting member is properly inserted into the recess 42 and thus in a fixed position, there is almost no risk of it slipping out of the recess. However, in exceptional cases in a particular impact event, it is not impossible for it to slip out.

[0027] FIG. 4 shows a mechanism 6A for driving an indicator during a jump according to a second embodiment of the present invention. The essential difference between this mechanism 6A and that of the first embodiment lies in that the connecting member 20A has a different shape and the outer shape of the recess 42A intended to receive it is also different. The recess 42A disposed in the side wall 40A of the drum finger 10A has an overall triangular shape and gradually opens toward the internal space 11 of the drum finger 10A where the spring 16 is disposed. The shape of the portion of the connecting member 20A inserted into the recess from the side opening substantially corresponds to the shape of the recess. With this configuration, the connecting member can be easily inserted into the recess. However, a priori, although the recess is intended to be relatively deep, this member will come out extremely easily in the event of an impact if no other means for preventing such an event are provided. The means provided here to best maintain the connecting member within the recess, particularly in the event of an impact, are the shape of the inner portion of the connecting member, the shape of the central portion 24, and the relative arrangement of this inner portion and the central portion. In most possible situations, the inner portion of the connecting member abuts against the central portion 24 before the connecting member completely exits the recess. Further, the connecting member 20A is substantially aligned with the longitudinal axis of the oblong hole 26 such that when it receives a substantially radial acceleration, particularly a substantially radial acceleration directed toward the axis of rotation along the longitudinal axis of the recess 42A, a more rigid drum finger 10A undergoes the same radial movement in the same direction. Thereby, the connecting member tends to be held within the recess.

[0028] In this second embodiment, once the connecting member 20A is inserted into its recess 42A, it is held in a fixed position within the recess by the radial force exerted by the spring against the side wall 40A of the drum finger 10A. This radial force is increased during rapid date changes or during counterclockwise time corrections that cross midnight. This is due to the fact that when the drive finger subsequently retracts towards the axis of rotation 22 via the radial displacement of the drum finger. Even when the spring 16 is forced to expand in these situations, the connecting member normally remains within the recess. It is assumed that the drum finger undergoes rotation relative to the wheel platform 8 in a direction opposite to the relative rotational direction of the 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 rotational direction of the wheel platform. In the spring loading configuration, it is intended that the indicator be driven in a radial direction that passes through the center of this lateral surface in this rotational direction. The connecting member 20A has a lateral flange 48A that faces the said lateral surface. The lateral flange 48A is also inclined obliquely with respect to the axis of rotation 22 in the same direction as the said lateral surface, and each time the indicator is driven by the mechanism, the lateral flange 48A abuts at least partially against this lateral surface. The outer surface and the outer flange are relatively long. This special feature ensures that the connecting member is firmly held in the recess as soon as the spring 16 contracts. Specifically, the contact point or contact zone of the recess on which the spring force is exerted via the connecting member does not change when the spring is loaded. Furthermore, when the spring is loaded, the connecting member 20A cannot rotate about itself in the rotational direction of the wheel platform.

[0029] Figure 5 shows a mechanism 6B for jump-driving an indicator according to a third embodiment of the present invention. The difference between this embodiment and the previous embodiments is, firstly, that the connecting member 20B is inserted into a recess 42B that cannot exit through the side opening. An inevitable consequence of this feature relates to the assembly of the spring 16 to the rigid part 60, in which case the connecting part 20B must be axially inserted into the recess 42B. The connecting member has a rear heel 52 and a contact surface 54 that are intended to abut against the angular stop 28 when the load action on the spring has ended and before the indicator jumps. Secondly, the mechanism 6B differs from that of the previous embodiment in that the rigid part 60 does not form a drum finger. This rigid part is formed by an elongated plate 62, which has an oval hole 26 at the first end and a side wall 64 that descends (or ascends depending on the spatial position of this part) from the elongated plate at the second end, and whose 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 has an internal projection 66 that fits into a recess of the central hub (not shown) and is attached to rotate together with the wheel platform instead of being driven towards the central hub (not shown).

[0030] Continuing, reference is made to the preferred first embodiment to illustrate in detail the operation of the mechanism 6 for driving the timepiece movement 2, and in particular the date ring 4, using FIGS. 6A to 8B. It should be noted that in FIGS. 6A to 8B, the plate 38 of the drum finger 10 is not shown in order to better illustrate the elements arranged in the internal space 11 of the drum finger.

[0031] The rigid part 10 is rotatable with respect to the wheel platform 8 and is rotatably guided about the rotation axis 22 by a shaft formed by the hub 34 and passing through the oblong hole 26. Thereby, under the action of the interaction generating a progressive radial force between the tooth part 5 of the indicator 4 and the outer flank 13, the drive finger is allowed to retreat towards the rotation axis. Such a retreat is useful for retracting the drive finger 12 during the rapid correction of the date ring 4 in the rotation direction 30 of this indicator (the normal rotation direction intended for this pointer to be driven each time by the mechanism 6), or during the counterclockwise time correction, and also in the event that the finger abuts against the upper flank of the tooth part 5 in case of incorrect indexing of the indicator. The spring is arranged to contract when a load is applied so as to be able to generate a jump in the spring, especially a semi-instantaneous jump of the indicator. Further, when the coil 18 contracts as a result of the load on the spring, the angular displacement of the second end 19 of the spring, and thus of the drive finger 12, with respect to the wheel platform 8, and thus with respect to the first end 17 of the spring, is limited by the angular stop 28 attached to rotate together with the wheel platform 8. Preferably, the indicator and the mechanism are arranged such that, in normal operation, once the loading action on the spring preceding this jump has ended, and thus corresponding to the angular distance α determined by the angular stop, a jump by the indicator is made after the angular displacement has been stopped by the angular stop 28. In an advantageous embodiment, it should be noted that, in normal operation, a jump by the indicator is made before the angular displacement is stopped by the angular stop 28. In such a case, the angular stop becomes a spring protection stop.

[0032] In a general embodiment, the drive mechanism does not have any angular stops. The spring contracts and the coils of this spring expand freely between the two ends of the spring during the loading period.

[0033] Figures 6A through 6D show four consecutive states of mechanism 6 that drives date ring 4 during a jump, particularly a semi-instantaneous jump. Figures 6A through 6D each show mechanism 6 and date ring 4 when the ring is driven to change to the next date at midnight, when drive finger 12 comes into contact with teeth 5a of ring 4 and spring 16 is substantially angularly relaxed (i.e., no angular stress is applied), when the loading action on spring 16 has ended and contact surface 54 of connecting member 20 abuts against angular stop 28 after undergoing an angular displacement α relative to wheel platform 8, during the date jump that occurs when the mechanical energy stored in the contracted spring is applied to this drum finger, and at the end of the jump when the date ring has reached a substantially next stable position.

[0034] To prevent teeth 5a of indicator 4 from passing over or under drive finger 12 when the indicator is driven, it should be noted that the height including play between wheel platform 8 and the underside of teeth 5 is always provided to remain between the lower height including play and the upper height of the drive finger from the wheel platform. For this purpose, in an advantageous alternative embodiment, the lower height of the finger is less than the tooth thickness of tooth portion 5. Preferably, in a wristwatch incorporating timepiece movement 2, the distance between the upper height of the finger and the dial covering the drive mechanism and indicator is also designed to be less than the tooth thickness of tooth portion 5. Since the large height of finger 12 can rise at least from the underside of spring 16 to above plate 38 that defines the upper surface of mechanism 6, teeth 5a can be easily prevented from passing under or over finger 12.

[0035] Figures 7A and 7B show the behavior of mechanism 6 during rapid correction of date ring 4 by a control member operable by a user in a conventional manner. In the evening, for example, when wheel platform 8 and drum finger 10 are initially in the configuration shown in Figure 7A such that finger 12 is positioned between tooth 5a and tooth 5b preceding it in the rotational direction 30, finger 12 is in the path of tooth 5b of the indicator. Ring 4 is intended to progress rapidly in the rotational direction 30 corresponding to the single direction in which the date ring is driven. As shown in Figure 7B, as ring 4 rotates, tooth 5b of tooth portion 5 comes into contact with the arcuate outer flank 13 of finger 12 and then exerts a progressive radial force on this finger. This force moves drum finger 10, and thanks to the presence of oblong hole 26, its longitudinal axis becomes substantially aligned with the finger and the finger retreats towards the central hub and thus towards the axis of rotation 22. That is, finger 12 retreats and tooth 5b is allowed to follow the outer flank 13 of the finger until this tooth projects angularly beyond the finger. While the drum finger is displaced radially, the spring contracts radially and connecting member 20 moves so as to approach the central hub and central portion 24. Central portion 24 has a flared cavity intended to receive the inner portion of connecting member 20 when connecting member 20 approaches this central portion during rapid correction of the date ring. It should be noted that spring 16, and more precisely its coil 18, is also simultaneously expanded by the radial stress that the spring receives so as to be directed towards the axis of rotation of the wheel platform during rapid correction of the date ring.

[0036] Figures 8A and 8B show the behavior of mechanism 6 during the correction of the time displayed by the timekeeping mechanism. Thereby, the wheel platform 8 is rotated counterclockwise past midnight. In this case, the date ring 5 remains stationary in its stable position when the time is corrected. The series of states of mechanism 6 is similar to the series of states that occur during the rapid correction of the date display described above. When the wheel platform 8 and thus the drum finger 10 rotate in a direction opposite to the normal rotation direction 50 (corresponding to the clockwise direction of the time display), the arched outer flank 13 of the finger 12 comes into contact with the tooth 5a of the tooth part 5 (Fig. 8A), and while the drum finger continues to rotate, albeit more slowly than the wheel platform, the drive finger moves radially towards the axis of rotation 22, so that this finger retreats, but the stationary teeth extend along the outer flank 13 of the finger. Again, the spring 16 is forced to expand during such a correction.

[0037] Mechanism 6 is configured to prevent blocking during rapid date correction or counterclockwise time correction.

[0038] The invention further relates to a wristwatch comprising the timepiece movement 2 according to the invention. This movement is incorporated into a case, which further incorporates a dial arranged to allow the display of data that changes over time by jumps, in particular the date display.

Claims

1. A clock movement (2) provided with an indicator (4), wherein the clock movement (2) includes a mechanism (6, 6A, 6B) for jump-driving this indicator, the mechanism including a wheel platform (8) defining a rotation axis (22), a rigid part (10, 10A, 60) disposed 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 so as to rotate therewith, the second end being attached to the rigid part so as to rotate therewith, and each time at least the spring is loaded prior to a jump by the indicator and when the indicator is driven by the mechanism during this jump, the rigid part is rotatable relative to the wheel platform and is rotatably guided around the rotation axis (22) by a shaft passing through an opening (26) in this rigid part, and the drive finger is allowed to retreat towards the rotation axis under the action of a radial component of the force exerted on this drive finger, characterized in that the mechanism is arranged such that the spring (16) contracts when the spring is loaded and can subsequently cause the indicator to jump, an angular displacement of the second end of the spring and thus of the drive finger (12) relative to the wheel platform and thus of the first end of the spring is limited by an angular stop (28) attached to rotate with the wheel platform (8) when the coil contracts, of a clock movement.

2. The indicator and the mechanism are arranged such that a jump by the indicator, in normal operation, occurs after the angular displacement has been stopped by the angular stop when a load action on the spring preceding this jump has ended and thus corresponds to a determined angular distance (α). The clock movement according to claim 1.

3. The timepiece movement according to claim 2, characterized in that the first end (17) of the spring (16) is connected to a central part (24, 24B) attached to rotate together with the wheel platform (8).

4. The timepiece movement according to claim 3, characterized in that the mechanism (6) includes a central hub (34) defining a shaft passing through the opening (26) in the rigid part (10, 10A, 60), and the central hub (34) guides the rigid part to be rotatable and translatable while being attached to the central hub such that the wheel platform (8) and the central part (24) rotate together.

5. The rigid part is a plate (38, 62) extending above the spring, the plate (38, 62) having the opening (26) machined therein, and axial walls (40, 40A, 64) disposed at the edges of this plate, the axial walls (40, 40A, 64) being inclined towards the wheel platform formed by The timepiece movement according to any one of claims 1 to 4, characterized in that at least a part of the axial wall and a part of the plate laminated thereon jointly form the drive finger, and the drive finger has a height (H) extending at least from the lower side of the spring to the upper surface (39) of the plate.

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

7. The axial walls (40, 40A) have recesses (42, 42A) having lateral openings on the side of the spring (16), and the second end (19) of the spring is expanded by a member connecting to the rigid part (10), and the connecting member (20, 20A) is configured to be able to at least partially penetrate into the recess through the lateral opening, whereby the spring is allowed to apply a couple force to the rigid part (10, 10A), and thus the drive finger is allowed to drive the indicator. The timepiece movement according to claim 5, characterized by

8. The concave portions (42, 42A) and the connecting members (20, 20A) are configured such that a contact point or contact zone of the concave portion on which the force of the spring acts via the connecting member does not substantially change when the spring is under load, the timepiece movement according to claim 7.

9. The concave portions (42, 42A) and the connecting members (20, 20A) are configured such that when the spring is under load, the connecting member cannot substantially rotate about itself in the rotational direction of the wheel platform, the timepiece movement according to claim 7.

10. The concave portions (42, 42A) have lateral surfaces (46, 46A) that are obliquely oriented in the rotational direction (50) of the wheel platform (8). In a configuration where a load is applied to the spring, the indicator is intended to be driven in a radial direction passing through the center of the lateral surface in the rotational direction. The connecting members (20, 20A) have lateral flanks (48, 48A) facing the lateral surfaces. The lateral flanks (48, 48A) are also obliquely inclined in the same direction as the lateral surfaces (46, 46A) with respect to the rotation axis and abut against this lateral surface when the spring is under load and when the indicator is being driven to make the next jump, the timepiece movement according to claim 7.

11. The connecting member (20) has a rear heel (52) that blocks rotation of the connecting member about itself in the rotational direction (50) of the wheel platform, the timepiece movement according to claim 7.

12. The indicator is a minute indicator, an hour indicator, a date indicator, a day indicator, or a month indicator, and the indicator includes a toothed portion, the timepiece movement according to any one of claims 1 to 4.

13. The indicator (4) is a date ring including internal teeth (5), the timepiece movement according to claim 12.

14. A wristwatch comprising the timepiece movement (2) according to any one of claims 1 to 13.

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