A watch movement equipped with a mechanism for driving a jump indicator and a wristwatch 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 the indicator, and further to a wristwatch incorporating a timepiece movement provided with such a mechanism. More specifically, the indicator is a date indicator. [Background technology]

[0002] The patent document 1 describes a mechanism for driving a jump indicator, which advantageously overcomes the technical problems of the prior art by including a rigid drum finger rotatably and translatably guided by a hub passing through an oblong hole in the drum, and a spring disposed on the drum finger, connecting the drum finger to the wheel platform.

[0003] This drive mechanism has several drawbacks. First, the spring expands when the date ring is driven. Because the spring coils are intended to contact the inner wall of the drum when the spring is under load, the spring's expansion is limited and the spring's plastic zone is prevented from being reached. This results in a sudden decrease in the spring's effective length. Given the manufacturing tolerances of various components, the drive mechanism's load application time can vary. This is because the time at which the spring comes into contact with the inner wall of the drum varies with each application, and the angular position of the contact zone also varies. This results in inaccuracies in the time that triggers the ring to move to the next date. Another problem arises from the fact that the drive force is transmitted to the finger via the spring coils. This means that the spring must be sufficiently rigid / stiff throughout its entire length, specifically the section located between the contact zone with the drum wall and the connecting element at the second end of the spring, which ultimately must be able to withstand the additional torque generated from the moment of contact until the indicator jumps.

[0004] The diagram in Reference 1 shows that the spring coupling element is positioned in a shallow recess from which it can easily emerge. The two side surfaces of the recess are parallel to the radial direction passing through the middle of the recess, and the coupling element has two radial flanks. The angular width of the coupling element is smaller than that of the recess so that it can easily enter the recess. Furthermore, the coupling element is intended to have a large amount of play in the recess so that it can move in the recess. That is, it can easily be released from the recess with a relatively small impact. In this case, either when the spring is loaded against the teeth of the date ring or before the spring is loaded, the spring typically shows a slight expansion due to friction with the drum, but the coupling element escapes from the side of the finger radial drive flank. In this situation, the side wall of the drum exerts a radial force on the coupling element, which is subjected to a frictional force with the side wall. If the spring bearing against the date ring tooth is loaded and the coupling element disengages from the recess, it will then slide along the inner lateral surface, preventing a date jump until the drive wheel rotates at least once and the coupling element re-enters the recess (the best-case scenario, which would still result in the missed date jump and the correct date display being lost). Alternatively, the frictional force is sufficient to re-expand the spring, increasing it further until its coil contacts the side wall, causing a date jump at an indeterminate time. In the latter case, after the date jump, the drive of the drum relaxes the spring. If this situation recurs, the next date change will no longer occur around midnight. If the coupling element undergoes a predetermined, sudden angular displacement along the side wall (which is possible), this situation will be repeated at indeterminate and variable date increments for at least several days. In either case, the date drive mechanism will cease to function for at least several days as soon as the coupling element disengages from its recess. This is highly likely to occur in the case of the mechanism shown in the figure in Patent Document 1.

[0005] The geometry of the coupling member relative to the recess, which allows a large amount of play and a certain degree of mobility of the coupling member in the recess, creates other problems. Specifically, when the spring is loaded, the spring coils deform, causing the coupling member to rotate around itself. This rotation causes the coupling member to slide against the front wall of the recess, radially reducing the point of application of the spring's force on the drum finger as the spring is loaded. That is, for a given spring load level, the driving torque the spring exerts on the finger decreases in proportion to the reduction in the lever arm's application of the spring's force on the drum finger. This creates a problem because the finger's driving force on the indicator tooth decreases by the same factor for a given contact point. For a given driving torque required to jump the indicator, the spring must generate a force that corresponds to the reduction in the lever arm while the spring is loaded. This negatively impacts the performance of the timepiece movement, which must apply a large torque by loading the drive spring. This, in turn, requires the spring to be oversized.

[0006] Finally, another problem with the mechanism in question arises from the fact that, when the indicator is actuated, the spring coil exerts a radial force on the drum, directed outward from the area diametrically opposite the finger, thus essentially in the longitudinal direction of the oblong hole. This tends to move the finger away from the tooth of the ring. Therefore, especially in the event of a small impact in such a situation, the finger is more likely to pass the tooth without actuating the indicator. It should also be noted that in such a situation, the angular path over which the finger can drive the tooth by maintaining contact is reduced, allowing the finger to pass the tooth before receiving a driving torque sufficient to ensure a jump in the date. The date ring remains stationary in an intermediate position or returns to its previous stable position as soon as the finger passes the tooth. Furthermore, reducing the lever arm that applies the driving force to the tooth requires an increase in the required driving force for a given driving torque. This in turn requires an increase in the force provided by the spring, and therefore its tension. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] European Patent Application Publication No. 3828644 Summary of the Invention

[0008] The 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 mentioned above. The invention also aims to provide a timepiece movement provided with an indicator, which includes a mechanism for jump driving this indicator. This mechanism can be efficient and accurate in each timepiece movement including such a mechanism. Its operation is little or not disturbed by external stresses, such as shocks.

[0009] To this end, 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 arranged 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 together, and the second end is attached to the rigid part so as to rotate together, at least during loading of the spring prior to a jump by the indicator and during driving of the indicator by the mechanism during said jump. The rigid part is rotatable relative to the wheel platform and is rotatably guided about said rotation axis by a shaft passing through an opening in the rigid part, thereby allowing the drive finger to be retracted toward the rotation axis under the action of a radial component of a force exerted on the drive finger. The mechanism is arranged in such a way that the spring contracts when a load is applied to it so as to cause the indicator to jump, and in such a way that when the coil is contracted, the angular displacement of the second end of the spring, and therefore the drive finger, relative to the wheel platform and therefore the first end of the spring is limited by an angular stop mounted on the wheel platform for rotation therewith.

[0010] In a preferred embodiment, the indicator and mechanism are arranged so that each jump by the indicator occurs after said angular displacement has been stopped by an angular stop once the loading of the spring preceding that jump has ceased, in normal operation, and thus corresponds to a determined angular distance (from the angular position in which the spring is not angularly stressed).

[0011] According to this feature of the invention, to jump the indicator, the spring coil contracts over its entire length during loading, causing the indicator to jump and thus increment. The spring coil is left free to expand during loading. This is primarily due to the spring's dimensions and the characteristics of the material from which it is made, which are less critical than the active expansion of only a portion of the coil at the end of the spring's loading. Subsequently, the duration of loading the spring to a given couple that causes the indicator to jump depends solely on the spring itself, and in particular its stiffness. As long as the spring remains in its initial state and its stiffness does not change, the angular displacement between the two ends of the spring remains unchanged from one loading to the next, so the duration of the loading remains unchanged for each loading of the spring, and therefore each jump occurs at a given time that remains very precise. Furthermore, by compressing the spring, a constant radius is provided for applying the driving force of the finger to the tooth of the indicator it abuts, thereby optimizing the driving force, and therefore the driving torque, required to jump the indicator. Finally, by virtue of the spring being compressed, a wall around the periphery of the spring is not required. The function of that wall is to limit the expansion of the spring coils and significantly increase the force couple applied to the finger to jump the indicator. That is, the present invention does not require drum fingers, although drum fingers are provided in certain alternative embodiments.

[0012] The present invention also features an angular stop integral with the wheel platform, which limits the angular displacement of the second end of the spring relative to the first end to a predetermined, invariable angular distance, thereby preventing the spring from leaving its elastic range and, therefore, preventing deterioration of the spring. In the preferred embodiment described above, the angular stop is positioned so that, during normal operation, the indicator does not jump before the portion of the spring integral with or the second end of the spring abuts the angular 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, and this relative angular displacement is determined by the angular stop, not by the stiffness of the spring. In an advantageous alternative embodiment, the spring and angular stop are part of the same component.

[0013] According to another advantageous embodiment, the rigid part is formed by a plate extending above the spring, in which the opening is machined, and an axial wall arranged at the edge of the plate, inclined towards the wheel and capable of being placed on it. The axial wall and the part of the plate stacked thereon jointly form a drive finger, which has a height extending from at least the underside 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, which is configured to be able to penetrate at least partially into the recess when the spring is assembled to the rigid part, allowing the spring to exert a drive couple on the rigid part once in place.

[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, through which the spring force acts via the connecting member, does not substantially change when the spring is under load. The term "substantially" indicates that slight variations may occur during the short initial phase of spring loading. In particular, the force of the spring acting on the rigid part via the connecting member does not substantially change when the spring is under load. The point or zone where the coupling element is applied does not move substantially towards the centre of rotation, in particular by radial sliding or rotation about itself of the coupling element. To this end, in a particular alternative embodiment, the recess has a lateral surface oriented obliquely in the direction of rotation of the wheel platform. The indicator is intended to be driven in that direction of rotation, and in a spring-loaded configuration, the indicator is intended to be driven relative to a radial direction passing through the centre of this lateral surface. The coupling element has a lateral flank facing the lateral surface, which is also inclined obliquely in the same direction as the lateral surface with respect to the radial direction defined by the axis of rotation, and which at least partially abuts against the lateral surface when the indicator is driven during its next jump under spring load.

[0015] In a preferred embodiment, the coupling member and recess are configured so that the coupling member cannot substantially rotate about itself in the direction of rotation of the wheel platform when the spring is under load. The term "substantially" indicates that slight rotation may occur during the short, initial phase of spring loading. To this end, the coupling member advantageously has a rear heel that blocks rotation of the coupling member about itself in said direction of rotation of the wheel platform. This feature, combined with the configuration of the recess and coupling member in the specific alternative embodiment described above, is effective in preventing rotation of the coupling member about itself in the direction of rotation of the wheel platform, and thus in preventing the point of application of the spring force to the rigid part to which the finger is attached from changing, in particular 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, since the conversion of the energy stored in the spring into a 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. Thus, for a given drive force required to jump an indicator, the mechanism described here does not require the loss of leverage to be compensated for by additional torque. It should be noted that the mechanical energy consumed by the drive mechanism is extracted from the watch movement and directly affects its performance. [Brief explanation of the drawings]

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

[0017] [Figure 1] 1 is a top view of a timepiece mechanism according to a first embodiment of the invention, which mechanism is intended to drive a jump indicator, in particular in a semi-instantaneous jump. [Figure 2] FIG. 2 is an exploded perspective view of the timepiece mechanism of FIG. 1. [Figure 3] 2 is a perspective view of the drum finger and spring of the clockwork mechanism of FIG. 1, shown in an inverted position; FIG. [Figure 4] FIG. 4 is a view similar to FIG. 3 of the drum fingers and springs of a timepiece mechanism according to a second embodiment of the invention; [Figure 5] FIG. 4 is a view similar to FIG. 3 of the drum fingers and springs of a timepiece mechanism according to a third embodiment of the invention. [Figure 6A] 6A to 6D each partially show a timepiece movement according to a first embodiment in four successive states which occur when the date ring is driven by the drive mechanism. [Figure 6B] 6A to 6D each partially show a timepiece movement according to a first embodiment in four successive states which occur when the date ring is driven by the drive mechanism. [Figure 6C] 6A to 6D each partially show a timepiece movement according to a first embodiment in four successive states which occur when the date ring is driven by the drive mechanism. [Figure 6D] 6A to 6D each partially show a timepiece movement according to a first embodiment in four successive states which occur when the date ring is driven by the drive mechanism. [Figure 7A] 7A and 7B each partially show the timepiece movement in FIG. 6A in two successive states which occur when the date ring is rapidly driven in the date ring driving direction by a conventional control member. [Figure 7B] 7A and 7B each partially show the timepiece movement in FIG. 6A in two successive states which occur when the date ring is rapidly driven in the date ring driving direction by a conventional control member. [Figure 8A] 8A and 8B each partially show the timepiece movement of FIG. 6A in two successive states that arise when the hour hand is driven counterclockwise and thus the wheel platform is driven in a direction opposite to the driving direction of this platform when the date ring is driven. [Figure 8B]8A and 8B each partially show the timepiece movement of FIG. 6A in two successive states that arise when the hour hand is driven counterclockwise and thus the wheel platform is driven in a direction opposite to the driving direction of this platform when the date ring is driven. DETAILED DESCRIPTION OF THE INVENTION

[0018] A first preferred embodiment of a mechanism for driving indicators in jumps, in particular semi-instantaneous jumps, will be described with reference to Figures 1 to 3, and the operation of a timepiece movement according to the invention incorporating such a driving mechanism will be described with reference to Figures 6A to 8B. The jump indicators are, for example, minute, hour, date, day and month indicators.

[0019] The mechanism 6 for driving the jump indicator, in particular the date ring 4, comprises a wheel platform 8 having an axis of rotation 22, a rigid part 10 arranged on 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 rigid part 10 is rotatable relative to the wheel platform 8 and is rotatably guided about the axis of rotation 22 by a shaft passing through an opening 26 in the rigid part. In an alternative embodiment, shown by way of non-limiting example, the opening defines an oblong hole (hereinafter referred to as oblong hole 26). Typically, the first end 17 is mounted to rotate with the wheel platform 8, and the second end 19 is mounted to rotate with the rigid part, at least each time the spring is loaded before a jump by the indicator and when the indicator is driven by the mechanism during a jump. In a main alternative embodiment, the indicator is a date indicator, in particular a date ring. A first end 17 of the spring 16 is connected to a central part 24 that is mounted for rotation therewith on the wheel platform 8. Preferably, the spring and central part form one and the same part. The mechanism 6 includes a central hub 34 that defines a shaft that passes through an oblong hole 26 in the rigid part 10. The central hub 34 guides the rigid part 10 rotatably and translatably relative to the wheel platform 8, and the rigid part 10 and central part 24 are driven towards the central hub 34. The drive finger 12 has a substantially radial drive flank 14 and an arcuate outer flank 13 that gradually decreases in inclination with respect to a direction perpendicular to the radius as it approaches the drive flank.

[0020] The rigid part 10 is formed by a plate 38 and an axial wall 40 located at the edge of the plate. The plate 38 extends over the spring and has an oblong hole 26 drilled therein. The axial wall 40 is inclined toward the wheel platform, and in an alternative embodiment, the axial wall 40 may rest on the wheel platform. A portion of the axial wall 40 and a portion of the plate 38 stacked thereon together form the drive finger 12. The drive finger 12 has a height H that extends from at least the underside of the spring 16 to an upper surface 39 of the plate. The rigid part 10 thus forms a drum finger that defines an interior space 11 in which the spring is located.

[0021] The axial wall 40 has a recess 42 at 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 expanded by a member 20 connecting to the rigid part 10, the connecting member 20 being configured to be able to at least partially enter the recess, thereby allowing the spring to apply a drive couple to the rigid part 10. In particular, the connecting member is highly rigid.

[0022] In the first embodiment, the coupling element is configured to be able to at least partially enter the recess through the lateral opening. Furthermore, the recess 42 advantageously has a lateral surface 46 obliquely oriented in the direction of rotation 50 of the wheel platform 8. In this spring-loaded configuration, the indicator 4 is intended to be driven in a radial direction passing through the center of the lateral surface in this direction of rotation. The coupling element 20 has lateral flanks 48 facing the lateral surface, which are also obliquely inclined in the same direction as the lateral surface and at least partially abut against the lateral surface whenever the spring 16 is loaded to drive the jump indicator using the mechanism 6. This particular feature ensures that the coupling element is precisely held in a given drive position within the recess while the spring is tensioned during loading. In other words, the contact point or contact zone of the recess 42, onto which the spring force is exerted via the coupling element 20, does not change when the spring is loaded. Only slight variations occur during the short, initial phase of spring loading.

[0023] Advantageously, the coupling element and the recess are configured so that the coupling element cannot substantially rotate about itself in the direction of rotation of the wheel platform when the spring is under load. Only slight rotation occurs during the short, initial phase of spring loading. According to a particular feature, the coupling element 20 has for this purpose a rear heel 52 intended to prevent rotation of the coupling element about itself once it is positioned in the recess 42 in the direction of rotation 50 of the wheel platform (the direction of rotation intended to drive the indicator). This rear heel is expanded by a contact surface 54 and abuts against the angular stop 28 when the spring loading ends, causing the indicator to jump. Preferably, the angular stop 28 is located in the angular extension of the spring coil 18, between the first end 17 of the spring and the rigid ring 24, and is defined by one and the same part forming the rigid ring and the spring.

[0024] Once the coupling element 20 has been assembled to the drum finger 10, without any external stress, and in particular without any shocks, this coupling element remains coupled to the drum finger 10 at all times, whatever the state of the mechanism, i.e., in the state of non-angular stress on the spring during the period when there is no interaction between the toothing 5 of the indicator 4 and the drive finger 12, when the spring is loaded before the indicator jumps, when the indicator jumps, and also in the state of contraction when the spring is expanded and stressed, in particular when the wheel platform 8 is rotated in the direction opposite to the direction intended for driving the indicator 4 to correct the time in the counterclockwise direction. Consequently, during normal operation of the timepiece movement, the coupling element 20 remains coupled to the drum finger as intended, i.e. located in the recess 42, and thus integral with the drum finger.

[0025] It is noteworthy that the mechanism 6 is arranged so that, even if the coupling member 20 were to disengage from the recess 42 during an impact, the coupling member would not be able to move beyond the recess in the rotational direction 50 of the wheel platform 8, whatever the state of the mechanism was prior to such an impact. In the unlikely event of an impact that generates a force on the coupling member that would cause it to disengage from its recess, the spring is ready to return the coupling member to the recess. If the coupling member 20 is arranged upstream of the recess 42 relative to the direction in which the wheel platform is driven, the rigid part and the coupling member are arranged so that the spring drive by the wheel platform returns the coupling member to the recess after the drive finger 12 comes into contact with the tooth 5a of the indicator 4 for the next scheduled jump, but before the next indicator jump is made. As a result, the indicator jump is not lost, and the indicator continues to display the correct information.

[0026] In an advantageous alternative embodiment, the recess 42 has a smallest dimension on its opening side that is slightly smaller than the largest dimension of the connecting member radially perpendicular to the rotation axis 22 of the spring in its angularly relaxed state (coincident with the central axis of the rigid ring 24). Furthermore, the connecting member and the recess are typically arranged so that the connecting member cannot exit the recess without undergoing at least one translation relative to the rigid part, i.e., at least one rotation about itself (about its geometric center about an axis parallel to the rotation axis 22). To enter the recess through the side opening, the connecting member must rotate slightly about itself. Due to this particular feature, once the connecting member is properly inserted into the recess 42 and thus in position, there is almost no risk of it coming out of the recess, although it is possible that it could come out in exceptional cases during certain impact events.

[0027] FIG. 4 shows a mechanism 6A for driving an indicator during a jump according to a second embodiment of the present invention. This mechanism 6A differs essentially from the first embodiment 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, located in the side wall 40A of the drum finger 10A, has a generally triangular shape and gradually opens toward the interior space 11 of the drum finger 10A, in which the spring 16 is located. 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. This configuration allows the connecting member to be easily inserted into the recess, but despite the recess being intended to be relatively deep a priori, the connecting member would very easily come out in the event of an impact unless other measures to prevent this are provided. The measures 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 these portions. In most possible circumstances, the inner portion of the coupling member will abut against central portion 24 before the coupling member fully exits the recess. Furthermore, when coupling member 20A is subjected to a substantially radial acceleration, particularly along the longitudinal axis of recess 42A toward the axis of rotation, it is substantially aligned with the longitudinal axis of oblong hole 26 so that the more rigid drum finger 10A is subjected to the same radial movement in the same direction, which tends to retain the coupling member within the recess.

[0028] In this second embodiment, once inserted into its recess 42A, the coupling element 20A is held in place 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 a rapid date change or a counterclockwise time correction past midnight. This is due to the fact that the driving finger subsequently retracts toward the rotation axis 22 via the radial displacement of the drum finger. Even when the spring 16 is forcibly expanded in these situations, the coupling element 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 rotation 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 side surface 46A oriented obliquely to the normal direction of rotation of the wheel platform. In the spring-loaded configuration, the indicator is intended to be driven in this direction radially through the center of this side surface. The connecting member 20A has a lateral flank 48A facing the lateral surface. The lateral flank 48A is also inclined obliquely relative to the axis of rotation 22 in the same direction as the lateral surface, and the lateral flank 48A at least partially abuts the lateral surface whenever the indicator is actuated by the mechanism. The outer surface and flank are relatively long. This special feature ensures that the connecting member is firmly held in the recess as soon as the spring 16 contracts. In particular, the contact point or contact zone of the recess, onto which the spring force is exerted via the connecting member, does not change when the spring is under load. Furthermore, when the spring is under load, the connecting member 20A cannot rotate around itself in the direction of rotation of the wheel platform.

[0029] FIG. 5 shows a mechanism 6B for jump-driving an indicator according to a third embodiment of the present invention. This embodiment differs from the previous embodiments in that, first, the connecting member 20B is inserted into a recess 42B that cannot exit through a lateral opening. A consequence of this feature is the assembly of the spring 16 to the rigid part 60, in which case the connecting member 20B must be inserted axially into the recess 42B. The connecting member has a rear heel 52 and a contact surface 54 that are intended to come into contact with the angular stop 28 when the spring load is terminated and before the indicator jumps. Secondly, the mechanism 6B differs from the previous embodiments in that the rigid part 60 does not form a drum finger; instead, it is formed by an elongated plate 62 having an oblong hole 26 at a first end and a side wall 64 that depends from the elongated plate (or rises, depending on the spatial position of this part), and whose main part forms the drive finger 12. It should be noted that the central portion 24B to which the first end 17 of the spring 16 is connected is not driven into a central hub (not shown), but has an internal protrusion 66 that fits into a recess in the central hub and is mounted to rotate with the wheel platform.

[0030] Continuing, reference will be made to the first preferred embodiment, using Figures 6A to 8B, to illustrate in detail the operation of the timepiece movement 2, in particular the mechanism 6 that drives 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.

[0031] The rigid part 10 is rotatable relative to the wheel platform 8 and is rotatably guided about the axis of rotation 22 by a shaft formed by the hub 34 and passing through the oblong hole 26. This allows the drive finger 12 to retract towards the axis of rotation under the action of the interaction between the toothing 5 of the indicator 4 and the outer flank 13, which generates a gradual radial force. Such retraction is useful for retracting the drive finger 12 during a rapid correction of the date ring 4 in the direction of rotation 30 of the indicator (the normal direction of rotation in which the pointer is intended to be driven in each case by the mechanism 6) or during a counterclockwise time correction, as well as in the event that the finger abuts against the upper flank of the toothing 5 in the event of an incorrect indexing of the indicator. The spring is arranged to compress when loaded so as to be able to generate a jump, in particular a semi-instantaneous jump of the indicator. Furthermore, when the coil 18 contracts as a result of the spring load, the angular displacement of the second end 19 of the spring, and therefore of the drive finger 12, relative to the wheel platform 8 and therefore relative to the first end 17 of the spring, is limited by an angular stop 28 mounted for rotation therewith on the wheel platform 8. Preferably, the indicator and mechanism are arranged such that, in normal operation, a jump by the indicator occurs after the angular displacement has been stopped by the angular stop 28 once the loading of the spring preceding this jump has ceased, and thus corresponds to the angular distance α determined by the angular stop. It should be noted that in an advantageous embodiment, in normal operation, the jump by the indicator occurs before its angular displacement is stopped by the angular stop 28. In such a case, the angular stop becomes a spring protection stop.

[0032] In a typical embodiment, the drive mechanism does not have any angular stops: the spring contracts and the coils of the spring are free to expand between the ends of the spring during loading.

[0033] 6A to 6D show four successive states of the mechanism 6 driving the date ring 4 during a jump, in particular a semi-instantaneous jump. Figures 6A to 6D respectively show the mechanism 6 and the date ring 4 when this ring is driven at midnight to change to the next date, when the driving finger 12 comes into contact with the tooth 5a of the ring 4 and the spring 16 is substantially angularly relaxed (i.e. unstressed); once the loading of the spring 16 has ended and the contact surface 54 of the linkage 20 comes into contact with the angular stop 28 after undergoing an angular displacement α relative to the wheel platform 8; during the date jump, which occurs when the mechanical energy stored in the compressed spring is applied to this drum finger; and at the end of the jump, when the date ring has substantially reached its next stable position.

[0034] It should be noted that, in order to prevent the tooth 5 a of the indicator 4 from passing above or below the driving finger 12 when the indicator is driven, the height, including play, between the wheel platform 8 and the underside of the tooth 5 is set so as to always remain between the lower and upper heights, including play, of the driving finger from the wheel platform. To this end, in an advantageous alternative embodiment, the lower height of the finger is smaller than the thickness of the teeth of the toothing 5. Preferably, in a watch incorporating the timepiece movement 2, the distance between the upper height of the finger and the dial covering the drive mechanism and the indicator is also designed to be smaller than the thickness of the teeth of the toothing 5. The large height of the finger 12 can rise at least from the underside of the spring 16 to above the plate 38 that defines the upper side of the mechanism 6, making it easy to prevent the tooth 5 a from passing above or below the finger 12.

[0035] 7A and 7B illustrate the behavior of mechanism 6 during rapid adjustment of date ring 4 by a user-operable control member in a conventional manner. For example, in the evening, when wheel platform 8 and drum finger 10 are initially in the configuration shown in FIG. 7A , finger 12 is positioned between tooth 5a and the preceding tooth 5b in the direction of rotation 30, and finger 12 is in the path of indicator tooth 5b. Ring 4 is intended to rapidly advance in the direction of rotation 30, which corresponds to the single direction in which the date ring is driven. As shown in FIG. 7B , as ring 4 rotates, tooth 5b of toothing 5 comes into contact with the arched outer flank 13 of finger 12 and then exerts a progressive radial force on said finger. This force moves drum finger 10, whose longitudinal axis, thanks to the presence of oblong hole 26, is substantially aligned with the finger, causing it to retract toward the central hub and, therefore, toward rotation axis 22. 16, that is, finger 12 retracts, allowing tooth 5b to follow the outer flank 13 of the finger until it angularly projects beyond the finger. During the radial displacement of the drum finger, the spring contracts radially and coupling member 20 moves closer to the central hub and central portion 24. Central portion 24 has a flared cavity intended to receive the inner portion of coupling member 20 when it approaches this central portion during quick adjustment of the date ring. It should be noted that both spring 16, and more precisely its coil 18, are simultaneously expanded by the radial stress to which it is subjected during quick adjustment of the date ring, moving towards the axis of rotation of the wheel platform.

[0036] 8A and 8B show the behavior of mechanism 6 during the correction of the time displayed by the timepiece mechanism. This causes wheel platform 8 to rotate counterclockwise past midnight. In this case, date ring 5 remains stationary in the stable position in which the time was corrected. The sequence of states of mechanism 6 is similar to that occurring during the rapid correction of the date display described above. When wheel platform 8, and thus drum finger 10, rotates in the direction opposite to the normal direction of rotation 50 (corresponding to the clockwise direction of the time display), the arched outer flank 13 of finger 12 comes into contact with tooth 5a of toothing 5 (FIG. 8A). The drum finger continues to rotate, albeit more slowly than the wheel platform, while the drive finger moves radially toward rotation axis 22, causing this finger to retract, while the immobile tooth extends along the outer flank 13 of the finger. Again, spring 16 is forced to expand during such a correction.

[0037] The mechanism 6 is configured to prevent blocking during rapid date adjustment or counterclockwise time adjustment.

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

Claims

1. A clock movement (2) provided with an indicator (4), The timepiece movement (2) includes a mechanism (6, 6A, 6B) for jump-driving the indicator (4), the mechanism (6, 6A, 6B) including a wheel platform (8) defining an axis of rotation (22), a rigid part (10, 10A, 60) positioned above the wheel platform (8) and defining a drive finger (12) for driving the indicator (4), and a spring (16) formed by a first end (17), a coil (18) and a second end (19), the first end (17) being attached to the wheel platform (8) for rotation therewith and the second end (19) being attached to the rigid part (10, 10A, 60) for rotation therewith. the rigid part (10, 10A, 60) is rotatably guided about the axis of rotation (22) by a shaft rotatable relative to the wheel platform (8) and passing through an opening (26) in the rigid part (10, 10A, 60), at least each time the spring (16) is loaded prior to a jump by the indicator (4) and when the indicator (4) is driven by the mechanism (6, 6A, 6B) during this jump, the drive finger (12) is allowed to retract towards the axis of rotation (22) under the action of a radial component of the force exerted on the drive finger (12); Features include: The mechanism (6, 6A, 6B) is arranged so that the spring (16) contracts when it is under load and can subsequently cause the indicator (4) to jump; the angular displacement of the second end (19) of the spring (16), and therefore the drive finger (12), relative to the wheel platform (8) and therefore the first end (17) of the spring (16), is limited by an angular stop (28) mounted to the wheel platform (8) for rotation therewith when the coil (18) is contracted; Clock movement (2).

2. 2. A timepiece movement (2) according to claim 1, characterized in that the indicator (4) and the mechanism (6, 6A, 6B) are arranged in such a way that a jump by the indicator (4) takes place in normal operation after the angular displacement has been stopped by the angular stop (28) once the load on the spring (16) preceding the jump has ceased and thus corresponds to a determined angular distance (α).

3. 3. A clock movement (2) according to claim 2, characterized in that the first end (17) of the spring (16) is connected to a central part (24, 24B) mounted to the wheel platform (8) for rotation therewith.

4. 4. The timepiece movement (2) according to claim 3, characterized in that the mechanism (6) includes a central hub (34) defining the shaft passing through the opening (26) in the rigid part (10, 10A, 60), the central hub (34) rotatably and translatably guiding the rigid part (10, 10A, 60) while attached to the central hub (34) so ​​that the wheel platform (8) and the central part (24) rotate together.

5. The rigid part (10, 10A, 60) a plate (38, 62) extending above the spring (16), the plate (38, 62) having the opening (26) machined therein; an axial wall (40, 40A, 64) disposed at the edge of the plate, the axial wall (40, 40A, 64) being inclined toward the wheel platform (8); is formed by 5. A clock movement (2) according to any one of claims 1 to 4, characterized in that at least a portion of the axial wall (40, 40A, 64) and a portion of the plate (38, 62) stacked thereon jointly form the drive finger (12), the drive finger (12) having a height (H) extending at least from the underside of the spring (16) to the upper surface (39) of the plate (38, 62).

6. 6. A clock movement (2) according to claim 5, characterized in that said rigid parts (10, 10A) form drum fingers which define an interior space (11) in which said spring (16) is located.

7. The axial wall (40, 40A) has a recess (42, 42A) with a lateral opening on the side of the spring (16); The second end (19) of the spring (16) is expanded by a connecting member (20, 20A) connected to the rigid part (10), and the connecting member (20, 20A) is configured to be able to at least partially enter the recess (42, 42A) through the side opening, thereby allowing the spring (16) to apply a force couple to the rigid part (10, 10A), and thus allowing the drive finger (12) to drive the indicator (4).

6. A clock movement (2) according to claim 5, characterized in that

8. 8. The timepiece movement (2) according to claim 7, characterized in that the recess (42, 42A) and the connecting member (20, 20A) are configured in such a way that the contact point or contact zone of the recess (42, 42A) on which the force of the spring (16) is exerted via the connecting member (20, 20A) does not substantially change when the spring (16) is under load.

9. 8. The timepiece movement (2) according to claim 7, characterized in that the recess (42, 42A) and the coupling member (20, 20A) are configured so that the coupling member (20, 20A) cannot substantially rotate around itself in the direction of rotation of the wheel platform (8) when the spring (16) is under load.

10. 8. The timepiece movement (2) according to claim 7, characterized in that the recess (42, 42A) has lateral surfaces (46, 46A) oriented obliquely in the direction of rotation (50) of the wheel platform (8), in a configuration for loading the spring (16) such that in said direction of rotation (50) the indicator (4) is intended to be driven in a radial direction passing through the center of the lateral surfaces (46, 46A), and the connecting element (20, 20A) has lateral flanks (48, 48A) facing the lateral surfaces (46, 46A), which are also inclined obliquely in the same direction as the lateral surfaces (46, 46A) relative to the axis of rotation (22), and which abut against the lateral surfaces (46, 46A) when the spring (16) is under load and when the indicator (4) is driven to make the next jump.

11. 10. The timepiece movement (2) according to claim 9, characterized in that the connecting member (20) has a rear heel (52) that blocks the rotation of the connecting member (20, 20A) around itself in the rotation direction (50) of the wheel platform (8).

12. 5. The timepiece movement (2) according to any one of claims 1 to 4, characterized in that the indicator (4) is a minute indicator, an hour indicator, a date indicator, a day indicator or a month indicator, and the indicator (4) comprises a toothing.

13. 13. A timepiece movement (2) according to claim 12, characterized in that the indicator (4) is a date ring with internal teeth (5).

14. A wristwatch, characterized in that it includes a clock movement (2) according to any one of claims 1 to 4.

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