Clock movement provided with a drive mechanism for a jumping indicator

Abstract

The clockwork movement (2) is provided with an indicator (4) and comprises a mechanism (6) for driving this indicator by jumping, the mechanism comprising a wheel board (8), a rigid part (10) defining a drive finger (12), and a spring (16) having a first end integral in rotation with the wheel board and a second end integral in rotation with the rigid part. The mechanism is arranged so that the spring works in contraction when this spring is loaded in order to be able to generate a jump of the indicator.Then, an angular displacement of the drive finger, relative to the wheel board, is limited, during a constraint of the spring in contraction, by an angular stop (28) integral in rotation with the wheel board, the indicator and the mechanism being arranged in such a way that a jump of the indicator cannot, in normal operation, occur before said angular displacement is stopped by the angular stop, at the end of a loading of the spring preceding this jump, and then corresponds to a predetermined angular distance (a).

Description

Technical field of the invention

[0001] The present invention relates to a watch movement provided with an indicator and comprising a mechanism for driving this indicator by jumping, as well as a watch incorporating a watch movement provided with such a mechanism. In particular, the indicator is a date indicator. Technological background

[0002] Document EP 3828644 describes a drive mechanism for a jumping indicator which advantageously addresses prior technical problems by the fact that it comprises a rigid drum finger, guided in rotation and translation by a hub passing through an oblong hole in the drum, and a spring arranged in this drum finger and connecting the latter to a wheel board.

[0003] This drive mechanism has various disadvantages. Firstly, the spring works by expanding when driving the date ring and its coil is designed to come into contact with the inner wall of the drum when the spring is loaded, so as to limit the expansion of this spring to avoid reaching the plastic domain of the spring. This has the consequence of suddenly reducing the active length of the spring. Given the manufacturing tolerances of the various elements, the loading time of the drive mechanism can vary, because the moment when the spring comes into contact with the inner wall of the drum can vary from one loading to another and the angular position of the contact zone can also vary. This causes an inaccuracy for the moment of triggering the transition of the ring to the next date.Then, another problem comes from the fact that the driving force is transmitted to the finger via the coil of the spring, which must therefore have sufficient rigidity / stiffness over its entire length and more particularly over the portion located between the contact zone with the wall of the drum and the coupling member to this drum arranged at the second end of the spring, this portion ultimately having to support the entirety of an additional torque generated up to the moment of the indicator jump from the instant of contact.

[0004] The figures of the aforementioned document show that the spring coupling member is arranged in a shallow housing from which this member can easily emerge. Indeed, the two lateral surfaces of the housing are parallel in a radial direction passing through the middle of the housing and the coupling member has two radial flanks, the angular width of the coupling member being provided to be less than that of the housing to allow this member to easily penetrate into the housing. In addition, it is provided that the coupling member has a large clearance in the housing, to allow mobility of this coupling member in the housing. Thus, a relatively small shock can easily result in the coupling member coming out of its housing.If this is the case, whether during loading of the spring bearing against a tooth of the date ring or before loading of this spring, which then generally presents a slight expansion due to the friction exerted on the drum, the coupling member comes out from the side of the radial driving flank of the finger. In this situation, the side wall of the drum exerts a radial force on the coupling member so that it undergoes a friction force on this side wall.If the coupling member comes out of its housing when the spring is loaded against a tooth of the date ring, it either slides along the inner side surface and the date jump will not take place at least until the drive wheel has made one revolution and the coupling member enters its housing again (the most favorable case which, however, results in the loss of a correct display of the date, which has missed a daily jump), or the friction force is sufficient for the spring to be loaded again by expansion, further increasing the friction force, until its coil touches the side wall and a date jump takes place at an undetermined time. In the latter case, after the date jump, the spring will relax, driving the drum. If this situation is repeated, then the following date changes will no longer occur around midnight.If the coupling member undergoes a certain sudden angular displacement along the side wall, which is likely, then this situation will repeat itself for at least a few days with increments of the date at indeterminate and variable times. In any case, the date drive mechanism is no longer functional for at least a few days as soon as the coupling member is removed from its housing, a very likely event for the mechanism as shown in the figures of document EP 3828644.

[0005] The geometry of the coupling member relative to its housing, allowing for a large amount of play and some mobility of this coupling member in the housing, creates another problem. Indeed, when the spring is loaded, it will deform the coil of the spring and cause the coupling member to rotate on itself. This rotation will have the effect of sliding the coupling member against the front side wall of the housing so that the point of application of the spring force on the drum finger is reduced radially as the spring is loaded. Thus, for a given spring loading level, the driving torque provided by the spring on the finger decreases proportionally to the reduction in the lever arm for applying the spring force to the drum finger, which poses a problem because the driving force of the finger on the indicator tooth decreases in the same proportion for a given contact point.However, since a given driving torque is required to make the indicator jump, the spring will therefore have to generate a force that is all the higher as the said lever arm decreases during the loading of the spring, which negatively impacts the performance of the watch movement which loads the spring of the drive mechanism and must then provide more torque. This also requires a more robust dimensioning of the spring than necessary.

[0006] Finally, another problem with the mechanism in question results from the fact that, when driving the indicator, the coil of the spring exerts a radial force on the drum directed outwards in an area diametrically opposite the finger and thus substantially in the longitudinal direction of the oblong hole, which tends to move this finger away from the teeth of the ring. The finger then risks more easily passing a tooth without driving the indicator, in particular during a small shock in such a situation.It will also be noted that such a situation decreases the angular path over which the finger can drive a tooth while remaining in contact, so that it is possible for the finger to pass the tooth before it receives a driving torque over a sufficient angular distance to ensure a date jump, the date ring remaining stopped in an intermediate position or returning back to its previous stable position once the finger has passed the tooth. In addition, the reduction in the lever arm for applying the driving force to the tooth requires, for a given driving torque, an increase in the necessary driving force, which requires an increase in the force provided by the spring and therefore its tension. Summary of the invention

[0007] The invention aims to propose a mechanism for driving a jumping indicator which does not have the drawbacks of the prior art described above. The invention also aims to provide a watch movement provided with an indicator and comprising a mechanism for driving this indicator by jumping which is efficient, which can be precise in each watch movement comprising such a mechanism, and which is little or not disturbed in its operation by external constraints, for example shocks.

[0008] To this end, the invention relates to a watch movement provided with an indicator and comprising a mechanism for driving this indicator by jumping, the mechanism comprising a wheel plate defining an axis of rotation, a rigid part arranged above the wheel plate and defining a drive finger for the indicator, and a spring formed of a first end, a coil and a second end, the first end being integral in rotation with the wheel plate and the second end being integral in rotation with the rigid part at least during each loading of the spring preceding a jump of the indicator and the driving of the indicator by the mechanism during this jump.The rigid part is movable in rotation relative to the wheel board and guided in rotation about said axis of rotation by a shaft passing through an opening that this rigid part has and which allows a withdrawal of the drive finger towards the axis of rotation under the action of a radial component of a force exerted on this drive finger. The mechanism is arranged so that the spring works in contraction when this spring is loaded in order to be able to generate a jump of the indicator.

[0009] According to an advantageous embodiment, an angular displacement of the second end of the spring, and thus of the drive finger, relative to the wheel board, and thus to the first end of the spring, is limited, during a stress of the coil in contraction, by an angular stop integral in rotation with the wheel board.

[0010] In a preferred embodiment, the indicator and the mechanism are arranged so that each jump of the indicator occurs, in normal operation, after said angular displacement is stopped by the angular stop, at the end of a loading of the spring preceding this jump, and then corresponds to a determined angular distance (from the angular position in which the spring is not angularly constrained).

[0011] Thanks to the characteristics of the invention, for driving the indicator by jumping, the coil of the spring works in contraction over its entire length throughout the duration of the spring loading to make a jump of the indicator and thus increment this indicator. The coil of the spring is left free in development throughout the duration of the loading. This is firstly much less critical, for the dimensioning of the spring and the characteristics of the material forming it, than an expansion work where only a part of the coil is active in a terminal phase of the loading of the spring. Then, the duration of the loading of the spring, up to a given force torque to generate a jump of the indicator, depends only on the spring itself, in particular on its stiffness.As long as the spring remains in its initial state and in particular with an invariable stiffness, the angular displacement between the two ends of the spring remains invariable from one loading to another, so that the duration of the loading remains invariable for each loading of the spring and therefore the instant of each jump takes place at a determined instant which remains very precise. In addition, the work of the spring in contraction makes it possible to ensure a constant radius for the application of the driving force of the finger on the tooth of the indicator against which the finger presses, which makes it possible to optimize this driving force and therefore the driving torque to be provided to make a jump of the indicator. Finally, thanks to the work of the spring in contraction, it is not necessary to provide a wall on the periphery of the spring having the function of limiting the expansion of the coil of the spring and in addition to greatly increasing the torque applied to the finger to generate the jump of the indicator.Thus, the present invention does not require a finger drum, although a finger drum is provided in a particular embodiment.

[0012] The present invention is also remarkable in that, in the above-mentioned advantageous embodiment, the contraction work of the spring allows the arrangement of an angular stop secured to the wheel board which limits the angular displacement of the second end of the spring, relative to its first end, to a determined invariable angular distance, so as to prevent the spring from being able to leave its elastic domain and thus prevent this spring from deteriorating. In the above-mentioned preferred embodiment, the angular stop is arranged in such a way that, in normal operation, a jump of the indicator does not occur before a part secured to the second end of the spring or this second end comes to bear against the angular stop.Thus, the drive mechanism presents, during each loading of the spring, the same relative angular displacement between the drive finger and the wheel board, this relative angular displacement being defined no longer by the stiffness of the spring but by the angular stop. In an advantageous variant, the spring and the angular stop are part of the same part.

[0013] According to another advantageous embodiment, the rigid part is formed by a plate, which extends above the spring and in which said opening is machined, and an axial wall arranged at the edge of this plate and which lowers towards the wheel, on which it can rest. The axial wall and a part of the plate which is superimposed thereon together form the drive finger, which has a height which rises at least from below the spring to the upper surface of the plate. The axial wall has a housing having a lateral opening on the side of the spring. The second end of the spring is extended by a coupling member to the rigid part, this coupling member being configured so as to be able to penetrate, during an assembly of the spring with the rigid part, at least partially into the housing and, once in place, allow the spring to apply a driving force torque to the rigid part.

[0014] In an advantageous variant, the coupling member and the housing are configured in such a way that the contact point or contact area of ​​the housing on which the spring force is exerted, via the coupling member, does not vary substantially during loading of the spring. The term 'substantially' indicates that a slight variation may possibly occur in a short initial phase of loading of the spring. In particular, the point or area of ​​application of the spring force on the rigid part, via the coupling member, does not move substantially towards the center of rotation, in particular by radial sliding of the coupling member or by rotation of the latter on itself.For this purpose, in a particular variant, the housing has a lateral surface oriented obliquely in the direction of rotation of the wheel board, provided for driving the indicator, relative to a radial direction, in the spring loading configuration, passing through the middle of this lateral surface, and the coupling member has a lateral flank, opposite the lateral surface, which is also inclined obliquely, relative to a radial direction defined by the axis of rotation, in the same direction as the lateral surface and which presses at least partially against this lateral surface during loading of the spring and driving of the indicator during the following jump of this indicator.

[0015] In a preferred embodiment, the coupling member and the housing are configured in such a way that the coupling member can substantially prevent any rotation on itself, in the direction of rotation of the wheel board, when loading the spring. The term 'substantially' indicates that a slight rotation may possibly occur in a short initial phase of spring loading. For this purpose, the coupling member advantageously has a rear heel for blocking rotation of the coupling member on itself in said direction of rotation of the wheel board.This feature combined with the configurations of the housing and the coupling member, in the particular variant mentioned above, is effective in preventing any rotation of the coupling member on itself in the direction of rotation of the wheel board, and thus preventing the point of application of the spring force on the rigid part provided with the finger from varying, in particular from decreasing. The driving torque of the finger is therefore kept constant for a given force applied by the spring. This property is favorable to the efficiency of the drive mechanism because the conversion of the energy stored in the spring into driving torque of the finger on the indicator is directly proportional to the radius of application of the spring force on the rigid part. Thus, for a given driving force necessary for the indicator to jump, the mechanism described here does not need to compensate for the loss of lever arm with additional torque.It should be noted that the mechanical energy consumed by the drive mechanism, taken from the watch movement, directly influences its performance. Brief description of the figures

[0016] The aims, advantages and characteristics of the invention will be described below in more detail with the aid of the appended drawings, given as non-limiting examples, in which: there Figure 1 is a top view of a clockwork mechanism, according to a first embodiment of the invention, provided for driving a jumping indicator, in particular by semi-instantaneous jumping; Figure 2 is an exploded perspective view of the clockwork mechanism of the Figure 1 ; there Figure 3 is a perspective view of the drum finger and spring of the clockwork mechanism of the Figure 1 , shown in an inverted position; the Figure 4 is a view, similar to that of the Figure 3, of the drum finger and of the spring of the clockwork mechanism according to a second embodiment of the invention; Figure 5 is a view, similar to that of the Figure 3 , of the drum finger and of the spring of the clockwork mechanism according to a third embodiment of the invention; Figures 6A to 6D partially show a clockwork movement according to the first embodiment respectively in four successive states occurring during the driving of a date ring by the drive mechanism; Figures 7A and 7B partially show the clockwork of the Figure 6A respectively in two successive states occurring during rapid driving of the date ring, by a standard control member, in the direction of driving of the date ring; Figures 8A and 8B partially show the clockwork of the Figure 6Arespectively in two successive states occurring when the time display hands are driven counterclockwise and therefore the wheel plate in the opposite direction to the direction in which this wheel plate is driven when the date ring is driven. Detailed description of the invention

[0017] In reference to the Figures 1 to 3 , a first preferred embodiment of a drive mechanism for a jumping indicator will be described, in particular by semi-instantaneous jumping, and with reference to the Figures 6A to 8B the operation of a watch movement according to the invention incorporating such a drive mechanism will be described. The jumping indicator is, for example, an indicator of minutes, hours, dates, days or months.

[0018] The mechanism 6 for driving a jumping indicator, in particular a date ring 4, comprises a wheel plate 8 having an axis of rotation 22, a rigid part 10 arranged above the wheel plate and defining a drive finger 12 for the indicator, and a spring 16 formed of a first end 17, a coil 18 and a second end 19. The rigid part 10 is movable in rotation relative to the wheel plate 8 and guided in rotation about the axis of rotation 22 by a shaft passing through an opening 26 that this rigid part has. The opening defines in the variant shown, by way of non-limiting example, an oblong hole (thus we will speak hereinafter of an oblong hole 26 in the description).Generally, the first end 17 is rotationally fixed to the wheel plate 8 and the second end 19 is rotationally fixed to the rigid part at least during each loading of the spring preceding a jump of the indicator and the driving of the indicator by the mechanism during this jump. In a main variant, the indicator is a date indicator, in particular a date ring. The first end 17 of the spring 16 is connected to a central part 24 which is rotationally fixed to the wheel plate 8. Preferably the spring and the central part form a single part. The mechanism 6 comprises a central hub 34 defining a shaft which passes through the oblong hole 26 of the rigid part 10 and guides this rigid part in rotation and translation relative to the wheel plate 8, the latter and the central part 24 being driven onto the central hub 34.The drive finger 12 has a substantially radial drive flank 14 and an outer flank 13 which is arched and whose slope decreases progressively, relative to a direction perpendicular to the radius, when approaching the drive flank.

[0019] The rigid part 10 is formed by a plate 38, which extends above the spring and in which an oblong hole 26 is machined, and an axial wall 40 arranged at the edge of this plate and which lowers towards the wheel board, on which it can rest in a variant. A part of the axial wall 40 and a part of the plate 38 which is superimposed thereon together form the drive finger 12, which has a height H which extends at least from below the spring 16 to the upper surface 39 of the plate. Thus, the rigid part 10 forms a drum finger which defines an interior space 11 in which the spring is arranged.

[0020] The axial wall 40 has, at the level of the drive finger 12, a housing 42 with a lateral opening on the side of the spring 16. The second end 19 of the spring is extended by a member 20 for coupling to the rigid part 10, this coupling member 20 being configured so as to be able to penetrate at least partially into the housing and thus allow the spring to apply a driving force torque to the rigid part 10. In particular, the coupling member is rigid.

[0021] In the first embodiment, the coupling member is configured to be able to penetrate at least partially into the housing through the lateral opening. In addition, the housing 42 advantageously has a lateral surface 46 oriented obliquely in the direction of rotation 50 of the wheel plate 8, provided for driving the indicator 4, relative to a radial direction, in the spring loading configuration, passing through the middle of the lateral surface, and the coupling member 20 has a lateral flank 48, facing the lateral surface, which is also inclined obliquely in the same direction as the lateral surface and which presses at least partially against the lateral surface during each loading of the spring 16 for driving the indicator jumping by the mechanism 6.This particular feature makes it possible to ensure precise maintenance of the coupling member in a given drive position inside the housing as soon as the spring is put under tension during loading. In other words, the contact point or contact area of ​​the housing 42 on which the spring force is exerted, via the coupling member 20, does not vary significantly during loading of the spring. Only a slight variation may possibly occur in a short initial phase of loading of the spring.

[0022] Advantageously, the coupling member and the housing are configured so that the coupling member 20 can substantially not undergo any rotation on itself, in the direction of rotation of the wheel board, during loading of the spring. Only a slight rotation may possibly occur in a short initial phase of loading of the spring. According to a particular characteristic, the coupling member 20 has for this purpose a rear heel 52 provided to block a rotation of the coupling member on itself, once in place in the housing 42, in the direction of rotation 50 of the wheel board (direction of rotation provided for driving the indicator). This rear heel is extended by a contact surface 54 which comes to bear against the angular stop 28 at the end of loading of the spring, to then cause a jump of the indicator.Preferably, the angular stop 28 is located between the first end 17 of the spring and the rigid ring 24, in the angular extension of the coil 18 of the spring, and is defined by the same part forming the rigid ring and the spring.

[0023] Once the coupling member 20 is assembled to the drum finger 10, without external constraints and in particular without an impact, this coupling member remains coupled to the drum finger at all times regardless of the state of the mechanism, that is to say in a state of the spring not angularly constrained in the periods without interaction between the teeth 5 of the indicator 4 and the drive finger 12, in a state where the spring works in contraction during a loading thereof before a jump of the indicator, during a jump of this indicator, and also when the spring is constrained in expansion in particular when the wheel plate 8 is driven in rotation in the direction of rotation opposite to the direction intended to drive the indicator 4, in order to carry out a correction of the time in the counterclockwise direction.In conclusion, in normal operation of the watch movement, the coupling member 20 remains coupled to the drum finger as intended, that is to say in place in the housing 42, and thus secured to the drum finger.

[0024] Remarkably, the mechanism 6 is arranged in such a way that, if the coupling member 20 possibly comes out of the housing 42 during an impact, this coupling member cannot move in the direction of rotation 50 of the wheel board 8 beyond this housing, whatever the state in which the mechanism is before such an impact. In the event of an impact generating a force on the coupling member which could possibly result in this coupling member coming out of its housing, which is very unlikely, the spring is then in a state which allows the coupling member to be returned to the housing.The rigid part and the coupling member are arranged in such a way that, if the coupling member 20 is located upstream of the housing 42 relative to the direction of drive of the wheel board, the drive of the spring by the wheel board brings the coupling member back into the housing after the drive finger 12 has come to bear against a tooth 5a of the indicator 4, to carry out the next planned jump, and before this next jump of the indicator occurs, so that no jump of this indicator is missed, the indicator thus continuing to display correct information.

[0025] In an advantageous variant, the housing 42 has a minimum dimension on the side of its opening which is slightly less than a maximum dimension of the coupling member perpendicular to the radial direction, relative to the axis of rotation 22 (merged with the central axis of the rigid ring 24), of the spring in an angularly relaxed state. More generally, the coupling member and the housing are arranged in such a way that the coupling member cannot come out of the housing by at least one translation relative to the rigid part, that is to say without undergoing at least one rotation on itself (rotation around its geometric center along an axis parallel to the axis of rotation 22). To enter the housing through the lateral opening, the coupling member must therefore perform a slight rotation on itself.This specific feature ensures that once the coupling member is properly inserted into the housing 42 and therefore in place, there is very little risk of it coming out of the housing, although this is not impossible in exceptional cases, during specific impacts.

[0026] To the Figure 4A mechanism 6A for driving an indicator by jumping according to a second embodiment of the invention is shown. This mechanism 6A is essentially distinguished from that of the first embodiment in that the coupling member 20A has a different shape and the profile of the housing 42A provided to receive it is also different. The housing 42A, arranged in the side wall 40A of the drum finger 10A, has a generally triangular shape and opens progressively towards the interior space 11 of the drum finger 10A in which the spring 16 is arranged. The shape of the part of the coupling member 20A which is inserted into the housing through the lateral opening corresponds substantially to that of the housing.This configuration allows the coupling member to be easily inserted into the housing, but would a priori allow this member to possibly come out in the event of an impact, although the housing is provided to be relatively deep, without other means provided to prevent such an event. The means provided here to best maintain the coupling member in the housing, in particular in the event of an impact, are the shape of the inner part of the coupling member and the shape of the central part 24 as well as the relative arrangement of this inner part and this central part. In most possible situations, the inner part of the coupling member abuts against the central part 24 before the coupling member completely comes out of the housing.In addition, the coupling member 20A is substantially aligned with the longitudinal axis of the oblong hole 26 so that, when it undergoes a substantially radial acceleration and in particular along the longitudinal axis of the housing 42A in the direction of the axis of rotation, the drum finger 10A, which is more massive, undergoes the same radial movement in the same direction, which tends to maintain the coupling member in the housing.

[0027] In this second embodiment, once inserted into its housing 42A, the coupling member 20A is held in place in its housing by the exertion of a radial force of the spring against the side wall 40A of the drum finger 10A. This radial force is increased during a rapid change of the date or during a correction of the time in the counterclockwise direction and passing through midnight, by the fact that the drive finger then undergoes a withdrawal towards the axis of rotation 22 via a radial displacement of the drum finger, so that the coupling member normally remains in the housing even when the spring 16 is forced into expansion in these situations, given that the drum finger undergoes a rotation relative to the wheel plate 8 in a direction opposite to the relative direction of rotation of this drum finger occurring during a drive of the date ring by the mechanism 6A.Preferably, as in the first embodiment, the housing 42A advantageously has a lateral surface 46A oriented obliquely in the normal direction of rotation of the wheel board, provided for driving the indicator, relative to a radial direction, in the spring loading configuration, passing through the middle of this lateral surface, and the coupling member 20A has a lateral flank 48A, opposite the lateral surface, which is also inclined obliquely in the same direction, relative to the axis of rotation 22, as the lateral surface and which presses at least partially against this lateral surface each time the indicator is driven by the mechanism. The lateral surface and the lateral flank have a relatively great length. This particular characteristic makes it possible to ensure good retention of the coupling member in the housing as soon as the spring 16 is put under tension in contraction.In particular, the contact point or contact area of ​​the housing on which the spring force is exerted, via the coupling member, does not vary during loading of the spring. In addition, the coupling member 20A cannot rotate on itself, in the direction of rotation of the wheel board, during loading of the spring.

[0028] To the Figure 5is shown a mechanism 6B for driving an indicator by jumping according to a third embodiment of the invention, which is distinguished from the previous embodiments firstly by the fact that the coupling member 20B is inserted into a housing 42B from which it cannot come out through the lateral opening. The corollary of this characteristic concerns the assembly of the spring 16 to the rigid part 60, the coupling part 20B having in this case to be inserted axially into the housing 42B. The coupling member has a rear heel 52 and a contact surface 54 provided to come into abutment against the angular stop 28 at the end of loading of the spring before a jump of the indicator.Then, the mechanism 6B is distinguished from that of the previous modes by the rigid part 60 which does not form a drum finger, this rigid part being formed of an elongated plate 62 having at a first end the oblong hole 26 and at the second end a lateral wall 64 which lowers (or rises depending on the spatial position of this part) of the elongated plate and the major part of which forms the drive finger 12. It will be noted that the central part 24B, to which the first end 17 of the spring 16 is connected, is not driven onto the central hub (not shown) but has an internal projecting part 66 which is inserted into a hollow of the central hub so as to be integral in rotation with the wheel board.

[0029] Subsequently, we return to the first embodiment, which is preferred, to expose, using the Figures 6A to 8B, in more detail the operation of the clock movement 2, in particular the mechanism 6 for driving a date ring 4. It will be noted that on the Figures 6A to 8B , the plate 38 of the drum finger 10 is not shown to better show the elements located in the interior space 11 of the drum finger.

[0030] The rigid part 10 is movable in rotation relative to the wheel board 8 and guided in rotation about the axis of rotation 22 by a shaft, formed by the hub 34, passing through the oblong hole 26, which allows a withdrawal of the drive finger towards the axis of rotation under the action of the interaction of the teeth 5 of the indicator 4 with the outer flank 13 which generates a progressively radial force. Such a withdrawal is useful to allow a retraction of the drive finger 12 during a rapid correction of the date ring 4 in the direction of rotation 30 of this indicator (normal direction of rotation provided during each drive of this indicator by the mechanism 6) or during a correction of the time in an anticlockwise direction, as well as in the case where the finger would come into abutment on the upper flank of the teeth 5 in the case of poor indexing of the indicator.The mechanism is arranged so that the spring 16 works in contraction when this spring is loaded in order to be able to generate a jump, in particular a semi-instantaneous jump of the indicator. In addition, an angular displacement of the second end 19 of the spring, and thus of the drive finger 12, relative to the wheel board 8, and thus to the first end 17 of the spring, is limited, during a stress of the coil 18 in contraction resulting from a loading of the spring, by an angular stop 28 integral in rotation with the wheel board 8. Preferably, the indicator and the mechanism are arranged so that, in normal operation, a jump of the indicator occurs after the angular displacement is stopped by the angular stop 28, at the end of a loading of the spring preceding this jump, and then corresponds to an angular distance α determined by the angular stop.It will be noted that in an advantageous embodiment, in normal operation, a jump of the indicator occurs before the angular movement is stopped by the angular stop 28. The angular stop is in this case a spring protection stop.

[0031] In a general embodiment, the drive mechanism does not have an angular stop. The spring works in contraction and the coil of this spring remains free in its development between the two ends of the spring during loading periods.

[0032] To Figures 6A to 6D are represented four successive states of the mechanism 6 for driving the date ring 4 by jump, in particular by semi-instantaneous jump. These Figures 6A to 6D show the mechanism 6 and the date ring 4, during a drive of this ring for the passage to a following date at midnight, respectively: At the moment when the drive finger 12 comes into contact against a tooth 5a of the ring 4 and when the spring 16 is substantially angularly relaxed (i.e. not angularly stressed); - at the end of the loading of the spring 16 when the contact surface 54 of the coupling member 20 comes into contact against the angular stop 28 after having undergone the angular displacement α relative to the wheel plate 8; - during the date jump generated by the supply of the mechanical energy stored in the contracted spring to this drum finger; - at the end of the jump when the date ring has substantially reached its next stable position.

[0033] It will be noted that, in order to prevent a tooth 5a of the indicator 4 from passing over or under the drive finger 12 when driving the indicator, it is provided that the height between the wheel plate 8 and the underside of the teeth 5, including clearance, remains constantly located between the lower height and the upper height of the drive finger relative to the wheel plate, including clearance. For this purpose, in an advantageous variant, the lower height of the finger is provided to be smaller than the thickness of the teeth of the teeth 5. Preferably, in a watch incorporating the watch movement 2, the distance between the upper height of the finger and a dial covering the drive mechanism and the indicator is also provided to be smaller than the thickness of the teeth of the teeth 5.The great height of the finger 12, which can rise at least from below the spring 16 to above the plate 38 which defines the upper surface of the mechanism 6, easily makes it possible to avoid the passage of a tooth 5a under or over the finger 12.

[0034] THE Figures 7A and 7B concern the behavior of the mechanism 6 during a rapid correction of the date ring 4, via a control member that can be manipulated by a user in a conventional manner, in the evening when the wheel board 8 and the drum finger 10 are for example initially in the configuration of the Figure 7A , so that the finger 12 is located between the tooth 5a and the tooth 5b which precedes it relative to the direction of rotation 30, so that the finger 12 is in the path of the tooth 5b of the indicator. The rapid advance of the ring 4 is provided in the direction of rotation 30 corresponding to the single driving direction of the date ring. As shown in Figure 7B, the tooth 5b of the toothing 5 comes into contact with the arcuate outer flank 13 of the finger 12 during the rotation of the ring 4 and then exerts on this finger a progressively radial force which moves the drum finger 10, thanks to the presence of the oblong hole 26 whose longitudinal axis is substantially aligned with the finger, so that the finger undergoes a withdrawal in the direction of the central hub and therefore of the axis of rotation 22. Thus the finger 12 retracts, leaving the tooth 5b to follow the outer flank 13 of the finger until this tooth angularly exceeds the finger. During radial movement of the drum finger, the spring contracts radially and the coupling member 20 approaches the central hub and the central part 24, which has a flared cavity intended to receive an interior part of the coupling member 20 when it approaches this central part during the rapid correction of the date ring.It will be noted that spring 16, more precisely its coil 18, is also forced into expansion during the rapid correction of the date ring, simultaneously with the radial stress that the spring undergoes towards the axis of rotation of the wheel plate.

[0035] THE Figures 8A and 8Bconcern the behavior of the mechanism 6 during a correction of a time displayed by the watch mechanism, which rotates the wheel plate 8, in an anticlockwise direction passing through midnight. In this case, the date ring 5 remains stationary in the stable position in which it is found during this time correction. The succession of states of the mechanism 6 is similar to that which takes place during the rapid correction of the date display described previously. During rotation of the wheel plate 8 and thus of the drum finger 10 in a direction opposite / inverse to the normal direction of rotation 50 (corresponding to the clockwise direction of the time display), the arcuate outer flank 13 of the finger 12 comes to bear against a tooth 5a of the toothing 5 ( Figure 8A) and the drum finger continues to rotate, however more slowly than the wheel board, while the drive finger moves radially towards the axis of rotation 22, so that this finger retracts while the stationary tooth runs along the outer flank 13 of the finger. Again the spring 16 is forced into expansion during such a correction.

[0036] Mechanism 6 is configured to prevent jamming during rapid date correction or counterclockwise time correction.

[0037] The invention also relates to a watch comprising a watch movement 2 according to the invention incorporated in a case, this case also incorporating a dial arranged so as to allow the display of data evolving temporally by jumps, in particular the display of the date.

Claims

1. Clock movement (2) provided with an indicator (4) and comprising a mechanism (6, 6A, 6B) for driving this indicator by jumping, the mechanism comprising a wheel board (8) defining an axis of rotation (22), a rigid part (10, 10A, 60) arranged above the wheel board and defining a drive finger (12) for the indicator, and a spring (16) formed of a first end (17), a coil (18) and a second end (19), the first end being rotationally fixed to the wheel board and the second end being rotationally fixed to the rigid part at least during each loading of the spring preceding a jump of the indicator and the driving of the indicator by the mechanism during this jump,the rigid part being movable in rotation relative to the wheel board and guided in rotation around said axis of rotation (22) by a shaft passing through an opening (26) which this rigid part has and which allows withdrawal of the drive finger towards the axis of rotation under the action of a radial component of a force exerted on this drive finger; characterized in that the mechanism is arranged so that the spring (16) works in contraction during each loading of this spring in order to then be able to generate a jump of the indicator.

2. Watch movement according to claim 1, characterized in that an angular displacement of the second end of the spring, and thus of the drive finger (12), relative to the wheel board, and thus to the first end of the spring, is limited, during a stress of the coil in contraction, by an angular stop (28) integral in rotation with the wheel board (8).

3. Watch movement according to claim 2, characterized in that the indicator and the mechanism are arranged so that a jump of the indicator occurs, in normal operation, after said angular displacement is stopped by the angular stop, at the end of a loading of the spring preceding this jump, and then corresponds to a determined angular distance (α).

4. Watch movement according to any one of claims 1 to 3, characterized in that the first end (17) of the spring (16) is connected to a central part (24, 24B) which is rotationally fixed to the wheel board (8).

5. Watch movement according to claim 4, characterized in that the mechanism (6) comprises a central hub (34) defining the shaft which passes through said opening (26) of the rigid part (10, 10A, 60) and guides this rigid part in rotation and translation, the wheel board (8) and the central part (24) being integral in rotation with the central hub.

6. Watch movement according to any one of the preceding claims, characterized in that the rigid part is formed by a plate (38, 62), which extends above the spring and in which said opening (26) is machined, and an axial wall (40, 40A, 64) arranged at the edge of this plate and which lowers towards the wheel board, at least a part of the axial wall and a part of the plate which is superimposed on it together forming the drive finger, which has a height (H) which extends at least from the underside of the spring to the upper surface (39) of the plate.

7. Watch movement according to claim 6, characterized in that the rigid part (10, 10A) forms a drum finger which defines an interior space (11) in which the spring (16) is located.

8. Watch movement according to claim 6 or 7, characterized in that the axial wall (40, 40A) has a housing (42, 42A) having a lateral opening on the side of the spring (16); and in that the second end (19) of the spring is extended by a coupling member to the rigid part (10), this coupling member (20, 20A) being configured so as to be able to penetrate at least partially into the housing through the lateral opening and then allow the spring to apply a torque to the rigid part (10, 10A) and thus to the drive finger to drive the indicator.

9. Watch movement according to claim 8, characterized in that the housing (42, 42A) and the coupling member (20, 20A) are configured such that the contact point or contact area of ​​the housing on which the spring force is exerted, via the coupling member, does not vary substantially during said loading of the spring.

10. Watch movement according to claim 8 or 9, characterized in thatthe housing (42, 42A) and the coupling member (20, 20A) are configured such that the coupling member can substantially not rotate on itself, in the direction of rotation of the wheel board, during said loading of the spring.

11. Watch movement any one of claims 8 to 10, characterized in thatthe housing (42, 42A) has a lateral surface (46, 46A) oriented obliquely in the direction of rotation (50) of the wheel board (8), provided for driving the indicator, relative to a radial direction, in the spring loading configuration, passing through the middle of this lateral surface, and the coupling member (20, 20A) has a lateral flank (48, 48A), opposite the lateral surface, which is also inclined obliquely, relative to said axis of rotation, in the same direction as the lateral surface (46, 46A) and which presses at least partially against this lateral surface during loading of the spring and during driving of the indicator during the following jump.

12. Watch movement any one of claims 8 to 11, characterized in that the coupling member (20) has a rear heel (52) for blocking rotation of the coupling member on itself in said direction of rotation (50) of the wheel board.

13. Watch movement according to any one of the preceding claims, characterized in that the indicator is an indicator of minutes, hours, dates, days or months, this indicator comprising teeth.

14. Watch movement according to claim 13, characterized in that the indicator (4) is a date ring comprising an internal toothing (5).

15. Watch characterized in that it comprises a clockwork movement (2) according to any one of the preceding claims.

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