Timepiece movement provided with mechanism for driving time-skipping indicator

Abstract

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

Description

TECHNICAL FIELD

[0001] The present utility model relates to a timepiece movement provided with an indicator and comprising a mechanism for driving this indicator to jump, and also to a watch incorporating a timepiece movement provided with such a mechanism. In particular, the indicator is a date indicator. BACKGROUND

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

[0003] This driving mechanism has a number of drawbacks. First, when the date ring is driven, the spring is stretched, and when the spring is loaded, its coil is intended to rest against the inner wall of the drum, thereby limiting the stretching of the spring and preventing it from reaching the plastic range of the spring. This results in a sudden reduction in the effective length of the spring. Taking into account the manufacturing tolerances of the various components, the loading time of this driving mechanism can vary, since the time at which the spring comes into contact with the inner wall of the drum can vary from one loading to the next, and the angular position of the contact zone can also vary. This results in an inaccurate time for triggering the movement of the ring to the next date. Another problem is due to the fact that the driving force is transmitted to the finger via the coil of the spring, so the spring must have sufficient rigidity / stiffness over its entire length, and more particularly in the part located between the contact zone with the wall of the drum and the coupling member for coupling with this drum, which is arranged at the second end of the spring, which part must ultimately withstand the entire additional torque generated from the moment of contact to the moment of jumping of the indicator.

[0004] The illustration in the above document shows that the coupling member of the spring is arranged in a shallow recess, this member can easily come out of this shallow recess. The two lateral surfaces of this recess are parallel along a radial direction passing through the middle of the recess and this coupling member has two radial sides, the angular width of the coupling member is less than the angular width of the recess to allow this member to easily penetrate the recess. Furthermore, the coupling member is intended to have a large amount of play in the recess to allow this coupling member to move in the recess. Thus, a relatively small impact can easily cause the coupling member to come out of its recess. If this is the case, when the spring is loaded against the teeth of the date ring or before loading this spring, the spring generally exhibits a slight expansion due to the frictional forces exerted on the drum, the coupling member comes out from the side of the radial driving side. In this case, the lateral wall of the drum exerts a radial force on the coupling member so that the coupling member is subjected to a frictional force on this lateral wall. If the coupling element comes out of its recess when the spring is loaded against the teeth of the date ring, it slides along the internal lateral surface and no date jump will occur until at least the driving wheel has rotated one turn and the coupling element re-enters its recess (this is the best case, but this results in the loss of the correct date display, missing the daily jump); or the frictional force is not sufficient to cause the spring to expand again, further increasing the frictional force until its coil touches the lateral wall, and the date jump occurs at an indeterminate time. In the latter case, after the date jump, the spring will relax by driving the drum. If this case occurs again, the next date change will no longer occur around midnight. If the coupling element experiences a certain sudden angular displacement along the lateral wall (which is possible), this case will be repeated for at least a few days, increasing the date at an indeterminate and variable time. In any case, once the coupling member comes out of its recess, the date driving mechanism will stop working for at least a few days, this event is extremely likely to occur for a mechanism as shown in the figures of patent document EP 3828644.

[0005] The geometry of the coupling member relative to its recess (allowing the coupling member to have a large amount of play and a certain mobility in the recess) creates another problem. More specifically, when the spring is loaded, it will deform the coil of the spring and cause the coupling member to rotate around itself. This rotation will cause the coupling member to slide on the front lateral wall of the recess so that the point of application of the force of the spring on the drum finger decreases radially when the spring is loaded. Thus, for a given spring load level, the driving torque provided by the spring on the finger is reduced in proportion to the reduction in the force applied by the spring on the drum finger through the lever arm, which poses a problem because the driving force on the teeth of the indicator decreases by the same proportion for a given point of contact. Since a given driving torque is needed to make the indicator jump, the spring will have to generate a greater force because the lever arm is reduced during the loading of the spring, which has a negative impact on the performance of the watch movement that loads the springs of the driving mechanism, and therefore a greater torque must be provided. This also requires the spring to be more robust in size than necessary.

[0006] Finally, another problem of the mechanisms discussed is due to the fact that, when the indicator is driven, the coil of the spring exerts a radial force on the drum which, in the area directly opposite the finger, points outwards and thus substantially along the longitudinal direction of the oblong hole, which tends to move the finger away from the teeth of the ring. The finger is thus more likely to pass over the teeth, in particular in the case of a small impact, with the indicator not being driven. It should also be noted that this situation reduces the angular path that the finger can drive the teeth by maintaining contact, so that the finger can pass over the teeth by an angular distance sufficient to ensure the date jump, the date ring remaining stationary in the intermediate position, or returning to its previous stable position after the finger has passed over the teeth. Furthermore, for a given driving torque, reducing the lever arm for applying the driving force to the teeth requires increasing the driving force required, which requires increasing the force supplied by the spring and thus also its tension. SUMMARY

[0007] The object of the present invention is to provide a mechanism for driving a jump indicator which does not have the drawbacks of the prior art described above. The present invention also aims to provide a timepiece movement provided with an indicator and comprising a mechanism for driving the jump of this indicator, which is efficient, which can be precise in each timepiece movement comprising such a mechanism, and whose operation is hardly disturbed by external stresses, such as impacts.

[0008] To this end, the present invention relates to a timepiece movement provided with an indicator and comprising a mechanism for driving the jump of this indicator, the mechanism comprising: a wheel platform defining an axis of rotation; a rigid portion arranged above the wheel platform and defining a driving finger for driving the indicator; and a spring formed of a first end, a coil and a second end, the first end being attached to the wheel platform to rotate therewith and the second end being attached to the rigid portion to rotate therewith at least during each loading of the spring before the jump of the indicator and during the driving of the indicator by the mechanism during this jump. The rigid portion can rotate relative to the wheel platform and is rotatably guided about said axis of rotation by a shaft passing through an opening in this rigid portion, and this allows the driving finger to retract towards the axis of rotation under the action of a radial component of the force exerted on this driving finger. The mechanism is arranged so that, when the spring is loaded, the spring retracts in order to be able to cause the jump of the indicator, and so that, when the coil retracts, the angular displacement of the second end of the spring, and thus of the driving finger, relative to the wheel platform, and thus to the first end of the spring, is limited by an angular stop attached to the wheel platform to rotate therewith.

[0009] In a preferred embodiment, the indicator and the mechanism are arranged such that, in normal operation, each jump of the indicator occurs after and thus corresponds to a determined angular distance (from the angular position in which the spring is unstressed) for which the angular displacement has been stopped by the angular stop after the spring loading has ended before this jump.

[0010] Thanks to the features of the application, in order to drive the indicator to jump, the coil of the spring is retracted over its entire length during the duration of the spring loading in order to cause the indicator to jump and thus to cause this indicator to increase the date. The coil of the spring is left free to expand during the duration of the loading. First of all, for the dimensions of the spring and the characteristics of the material forming the spring, this is far less important than the expansion of only part of the coil at the end of the spring loading. Thereafter, the duration of the spring loading (up to the given couple of forces causing the indicator to jump) depends only on the spring itself, in particular on its stiffness. As long as the spring remains in its initial state and in particular has an unchanged stiffness, the angular displacement between the two ends of the spring remains unchanged from one loading to the next, so that the duration of the loading remains unchanged for each loading of the spring and thus each jump occurs at a given time which remains very precise. Furthermore, by retracting the spring, a constant radius can be obtained to apply the driving force of the hand to the indicator tooth against which the hand is applied, so as to optimize this driving force and thus the driving torque required to cause the indicator to jump. Finally, thanks to the retraction of the spring, there is no need for a wall around the periphery of the spring, the role of which is to limit the expansion of the coil of the spring and to greatly increase the couple of forces applied to the hand to cause the indicator to jump. Thus, although drum hands are provided in certain alternative embodiments, the application does not require drum hands.

[0011] The features of the application also consist in the arrangement of the angular stop which is integral with the wheel platform, this stop limiting the angular displacement of the second end of the spring relative to the first end thereof to a predetermined and unchanged angular distance, so as to prevent the spring from leaving its elastic range and thus to prevent the spring from deteriorating. In the preferred embodiment described above, the angular stop is arranged such that, in normal operation, the indicator does not jump before the part integral with the second end of the spring or this second end abuts against the angular stop. Thus, each time the spring is loaded, the driving mechanism has the same relative angular displacement between the driving hand and the wheel platform, this relative angular displacement not being defined by the stiffness of the spring but by the angular stop. In an advantageous alternative embodiment, the spring and the angular stop are part of the same component.

[0012] According to another advantageous embodiment, the rigid part is formed by a plate extending above the spring and in which said opening is machined, and an axial wall arranged at the edge of this plate and inclined downwards towards the wheel on which it can rest. The axial wall and the part of the plate stacked thereon jointly form a drive finger whose height extends at least from the underside of the spring to the upper surface of the plate. The axial wall has a recess having a lateral opening on the spring side. The second end of the spring is prolonged by a member for coupling with the rigid part, this coupling member being configured so that, when the spring is assembled with the rigid part, it can at least partially penetrate the recess and, once in place, allow the spring to exert a drive force couple on the rigid part.

[0013] In an advantageous alternative embodiment, the coupling member and the recess are configured so that, when the spring is loaded, the point or zone of contact of the recess does not significantly change on which the spring force is exerted via the coupling member. The term "significantly" means that a slight change can occur in the short initial phase of spring loading. In particular, the point or zone of exertion of the spring force on the rigid part via the coupling member does not significantly move towards the centre of rotation, in particular by radial sliding of the coupling member or by rotation thereof around itself. To this end, in a particular alternative embodiment, the recess has a lateral surface obliquely oriented in the direction of rotation of the wheel platform, in the spring-loaded configuration, the indicator being intended to be driven in this direction relative to the radial direction, so as to pass through the centre of this lateral surface, and the coupling member has a lateral flank facing this lateral surface, which is also obliquely inclined in the same direction as the lateral surface relative to the radial direction defined by the axis of rotation, and which, when the spring is loaded and driven during the next jump of the indicator, at least partially abuts against this lateral surface.

[0014] In a preferred embodiment, the coupling member and the recess are configured so that, when the spring is loaded, the coupling member is substantially unable to rotate about itself in the direction of rotation of the wheel platform. The term "substantially" indicates that a slight rotation can occur during the short initial phase of spring loading. To this end, the coupling member advantageously has a heel for preventing the coupling member from rotating about itself in said direction of rotation of the wheel platform. In the particular alternative embodiment described above, this feature, in combination with the configuration of the recess and the coupling member, effectively prevents any rotation of the coupling member about itself in the direction of rotation of the wheel platform, and thus prevents the point of application of the force of the spring on the rigid portion on which the finger is mounted from varying, in particular from decreasing. The driving torque of the finger thus remains constant for a given force exerted by the spring. This property improves the efficiency of the driving mechanism, since the conversion of the energy stored in the spring into driving torque for driving the finger on the indicator is proportional to the radius of application of the force of the spring on the rigid portion. The mechanism described herein thus does not need to compensate for the lever loss by additional torque for a given driving force to cause a jump of the indicator. It should be noted that the mechanical energy consumed by the driving mechanism from the watch movement has a direct impact on its performance. BRIEF DESCRIPTION OF DRAWINGS

[0015] The object, advantages and features of the application will be described in greater detail below by means of the attached drawings given by way of non-limiting example in which:

[0016] - Figure 1 is a top view of a watch mechanism according to a first embodiment of the application, the mechanism being intended to drive a jumping indicator, in particular in a semi-instantaneous jumping manner;

[0017] - Figure 2 is an exploded perspective view of the watch mechanism in Figure 1 ;

[0018] - Figure 3 is a perspective view of the barrel finger and the spring of the watch mechanism in Figure 1 , shown in an inverted position;

[0019] - Figure 4 is a view similar to Figure 3 of the barrel finger and the spring of the watch mechanism according to a second embodiment of the application;

[0020] - Figure 5 is a view similar to Figure 3 of the barrel finger and the spring of the watch mechanism according to a third embodiment of the application;

[0021] - Figures 6A to 6D illustrates a watch movement according to the first embodiment, in four successive state parts occurring when the date ring is driven by the driving mechanism;

[0022] -Figure 7A and Figure 7B are respectively illustrated in two successive state parts Figure 6A of the timepiece movement in the

[0023] - Figure 8A and Figure 8B are respectively illustrated in two successive state parts Figure 6A of the timepiece movement in the DETAILED DESCRIPTION

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

[0025] The mechanism 6 for driving a jumping indicator, in particular a date ring 4, comprises a wheel platform 8 having a rotation axis 22, a rigid portion 10 arranged on this wheel platform and defining a driving finger 12 for driving the indicator, and a spring 16 formed by a first end 17, a coil 18 and a second end 19. The rigid portion 10 can rotate with respect to the wheel platform 8 and is rotatably guided about the rotation axis 22 by a shaft passing through an opening 26 in this rigid portion. In the alternative embodiment shown by way of non-limiting example, this opening defines an oblong hole, hereinafter referred to as oblong hole 26. Generally, at least whenever the spring is loaded before the indicator jumps, and when the indicator is driven by the mechanism during this jump, the first end 17 is attached to the wheel platform 8 to rotate therewith, and the second end 19 is attached to the rigid portion to rotate therewith. In a main alternative embodiment, the indicator is a date indicator, in particular a date ring. The first end 17 of the spring 16 is connected to a central portion 24 which is attached to the wheel platform 8 to rotate therewith. Preferably, the spring and the central portion form one and the same portion. The mechanism 6 comprises a central hub 34 defining a shaft passing through the oblong hole 26 in the rigid portion 10 and rotatably and translatable guiding this rigid portion with respect to the wheel platform 8, the wheel platform 8 and the central portion 24 being driven onto the central hub 34. The driving finger 12 has a substantially radial driving side 14 and an outer side 13 which is arcuate and whose slope progressively decreases with respect to a direction perpendicular to the radius as it approaches the driving side.

[0026] The rigid part 10 is formed by a plate 38 extending above the spring and in which an oblong hole 26 is machined, and an axial wall 40 arranged at an edge of this plate and inclined downward toward the wheel platform, which can rest on the wheel platform in an alternative embodiment. A portion of the axial wall 40 and a portion of the plate 38 stacked thereon jointly form a drive finger 12, the height H of which extends at least from the underside of the spring 16 to the upper surface 39 of the plate. The rigid part 10 thus forms a drum finger which defines an inner space 11 in which the spring is arranged.

[0027] The axial wall 40 has a recess 42 at the drive finger 12, the recess 42 having a lateral opening on the spring 16 side. The second end 19 of the spring is prolonged by a member 20 for coupling to the rigid part 10, this coupling member 20 being configured so that it can at least partially penetrate the recess and thus allow the spring to exert a drive force couple to the rigid part 10. In particular, this coupling member is rigid.

[0028] In the first embodiment, the coupling member is configured to be able to at least partially penetrate 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 which the indicator 4 is intended to be driven in relation to the radial direction in the configuration for loading the spring, so as to pass through the center of this lateral surface, and the coupling member 20 has a lateral side 48 facing this lateral surface, which is also obliquely inclined in the same direction as the lateral surface and which abuts at least partially against this lateral surface each time the spring 16 is loaded to drive the jumper indicator using the mechanism 6. This particular feature ensures that, once the spring is tensioned during loading, the coupling member is precisely held in a given drive position inside the recess. In other words, the contact point or zone of the recess 42 on which the spring force is exerted via the coupling member 20 does not significantly change when the spring is loaded. Only a slight change can occur during the short initial phase of spring loading.

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

[0030] Once the coupling member 20 has been assembled to the drum finger 10, this coupling member remains coupled to the drum finger at all times, without any external stress, and in particular without any shock, whatever the state of the mechanism, i.e. in the period when the toothed portion 5 of the indicator 4 is not interacting with the driving finger 12, in the state of non-angular stressing of the spring, in which the spring is contracted when it is loaded before the indicator jumps, at the time of the indicator jump and also when the spring is stressed in extension, in particular when the wheel platform 8 is rotating in the opposite direction to the intended direction for driving the indicator 4, for correcting time in the anticlockwise direction. In all, during normal operation of the timepiece movement, the coupling member 20 remains coupled to the drum finger as expected (i.e. in place in the recess 42) and is thus integral with the drum finger.

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

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

[0033] Figure 4 A mechanism 6A for driving the indicator to the time is shown according to a second embodiment of the application. This mechanism 6A essentially differs from that of the first embodiment in that the coupling member 20A has a different shape and the profile of the recess 42A intended to receive the coupling member is also different. The recess 42A arranged in the lateral wall 40A of the drum finger 10A has a global triangular shape and leads progressively to the internal space 11 of the drum finger 10A in which the spring is arranged. The shape of the part of the coupling member 20A inserted into the recess through the lateral opening substantially corresponds to the shape of the recess. This configuration allows the coupling member to be easily inserted into the recess, but will a priori allow this member to disengage in the event of an impact, even if the recess is intended to be relatively deep, without the need to provide other means to prevent this. The means provided here for best maintaining the coupling member in the recess, particularly 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 and the relative arrangement of this inner part with this central part. In the most likely case, before the coupling member disengages completely from the recess, the inner part of the coupling member abuts against the central part 24. 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 recess 42A towards the rotation axis, the more solid drum finger 10A undergoes the same radial movement in the same direction, which tends to keep the coupling member in the recess.

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

[0035] Figure 5 The mechanism 6B for driving the indicator to jump time according to the third embodiment of the application is shown, firstly, in which this embodiment differs from the previous embodiments in that the coupling member 20B is inserted into the recess 42B, which it cannot disengage via the lateral opening. The corollary of this feature involves the assembly of the spring 16 to the rigid portion 60, in which case the coupling portion 20B must be inserted axially into the recess 42B. This coupling member has a heel 52 and a contact surface 54, which is intended to abut against the angular stop 28 when the spring loading is finished and before the indicator jumps time. Secondly, the mechanism 6B differs from the previous embodiments in that the rigid portion 60 does not form the drum finger, this rigid portion being formed by an elongated plate 62 having an oblong hole 26 at a first end and a lateral wall 64 at a second end, which is lowered from this elongated plate (or raised according to the spatial position of this portion), the main part of which forms the driving 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 onto a central hub (not shown), but has an internal protrusion 66 which fits into a recess in the central hub, thereby being attached to the wheel platform to rotate therewith.

[0036] Subsequently, reference is made back to the first embodiment, which is preferred, in order to use Figures 6A to 8B The operation of the timepiece movement 2, in particular of the mechanism 6 for driving the date ring 4, is shown in more detail. It is noted that, in Figures 6A to 8B In the figures, the plate 38 of the barrel finger 10 is not shown in order to better illustrate the elements located in the inner space 11 of the barrel finger.

[0037] The rigid portion 10 can rotate with respect to the wheel platform 8 and is rotatably guided around the rotation axis 22 by the shaft formed by the hub 34 passing through the oblong hole 26, which allows the driving finger to retract towards the rotation axis under the effect of the interaction of the teeth 5 of the indicator 4 with the outer side 13, which generates a stepwise radial force. This retraction helps to allow the driving finger 12 to retract during the fast correction of the date ring 4 in the rotation direction 30 of this indicator, which is intended to be the normal rotation direction of this indicator each time it is driven by the mechanism 6, or during the anticlockwise time correction and when the finger abuts against the upper side of the teeth 5 in case of incorrect indexing of the indicator. The mechanism is arranged so that the spring 16, when this spring is loaded, retracts in order to be able to generate a jump hour, in particular a semi-instantaneous jump hour of the indicator. Furthermore, when the coil 18 retracts due to the spring loading, the angular displacement of the second end 19 of the spring, and thus of the driving finger 12, with respect to the wheel platform 8, and thus with respect to the first end 17 of the spring, is limited by the angular stop 28, which is attached to the wheel platform 8 so as to rotate therewith. Preferably, the indicator and the mechanism are arranged so that, in normal operation, the jump hour of the indicator occurs after and thus corresponds to an angular distance a determined by the angular stop, after which the angular displacement, before this jump hour, has been stopped by the angular stop 28. It is noted that, in an advantageous embodiment, in normal operation, the jump hour of the indicator occurs before the angular displacement has been stopped by the angular stop 28. In this case, the angular stop is a spring protection stop.

[0038] In a general embodiment, the driving mechanism does not have any angular stop. During the loading period, the spring retracts and the coil of this spring remains free to stretch between the two ends of the spring.

[0039] Figures 6A to 6D Four successive states of the mechanism 6 for driving a jump hour, in particular a semi-instantaneous jump hour, of the date ring 4 are shown. Figures 6A to 6DThe mechanism 6 and the date ring 4 are shown at the following instants when this ring is driven so as to change to the next date at midnight: when the driving finger 12 contacts the tooth 5a of the ring 4 and the spring 16 is substantially angularly relaxed (i.e. not angularly stressed), when the contact surface 54 of the coupling member 20 abuts against the angular stop 28 after the end of the loading of the spring 16, during the date jump generated by the mechanical energy stored in the contraction spring being applied to this drum finger, at the end of the jump when the date ring has substantially reached its next stable position.

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

[0041] Figure 7A and Figure 7B The behavior of the mechanism 6 during the rapid correction of the date ring 4 is shown, by means of a control member that the user can operate in a conventional manner, in the evening, the wheel platform 8 and the drum finger 10 being for example initially in the configuration shown in Figure 7A so that the finger 12 is located between the tooth 5a and the tooth 5b preceding it with respect to the direction of rotation 30, so that the finger 12 is in the path of the tooth 5b of the indicator. The ring 4 is intended to be rapidly advanced in the direction of rotation 30 corresponding to a single direction of driving of the date ring. As Figure 7BAs the ring 4 rotates, the teeth 5b of the toothed portion 5 contact the arcuate outer side 13 of the finger 12 and then exert a progressive radial force on this finger, which, due to the presence of the oblong hole 26, the longitudinal axis of which is substantially aligned with the finger, causes the drum finger 10 to move so that it retracts towards the central hub and thus towards the axis of rotation 22. The finger 12 thus retracts, thereby allowing the tooth 5b to follow the outer side 13 of the finger until this tooth projects angularly beyond the finger. During the radial displacement of the drum finger, the spring contracts radially and the coupling member 20 moves closer to the central hub and to the central portion 24, which has a flared cavity intended to receive the inner portion of the coupling member 20 as it approaches this central portion during the fast date correction date ring. It should be noted that the spring 16, more precisely its coil 18, also extends during the fast date correction date ring, while the spring is subjected to a radial stress towards the axis of rotation of the wheel platform.

[0042] Figure 8A and Figure 8B The behavior of the mechanism 6 during the correction of the time displayed by the timepiece mechanism is shown, which causes the wheel platform 8 to rotate in the counterclockwise direction to midnight. In this case, the stable position of the date ring 5 at the time of the correction of the time remains stationary. The succession of states of the mechanism 6 is similar to that described above which occurs during the fast correction of the date display. When the wheel platform 8, and thus the drum finger 10, rotates in the opposite direction to the normal direction of rotation 50, corresponding to the clockwise direction of the time display, the arcuate outer side 13 of the finger 12 abuts against the teeth 5a of the toothed portion 5 Figure 8A ) and the drum finger continues to rotate, but slower than the wheel platform, while the driving finger moves radially towards the axis of rotation 22 so that this finger retracts without the teeth that do not move extending along the outer side 13 of the finger. Once again, the spring 16 is forced to extend during this correction.

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

[0044] The utility model also relates to a watch comprising the timepiece movement 2 according to the utility model, the movement being incorporated into a watch case, the watch case also incorporating a dial which is arranged to allow the display of an item of data which varies with time by jumping, in particular a date display.

Claims

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

2. A timepiece movement according to claim 1, characterized in that, The indicator and the mechanism are arranged so that, in normal operation, the jump of the indicator takes place after and therefore corresponds to a determined angular distance (a) for which the angular displacement has been stopped by the angular stop after the spring loading before this jump has ended.

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

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

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

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

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

8. A timepiece movement according to claim 7, characterised in that, The recess (42, 42A) and the coupling member (20, 20A) are configured so that when the spring is loaded, the point or zone of contact of the recess does not significantly change, the spring force being exerted on this point or zone via the coupling member.

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

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

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

12. A watch movement according to any one of the preceding claims, characterised in that, The indicator is a minute indicator, an hour indicator, a date indicator, a week indicator or a month indicator, this indicator comprising a toothed portion.

13. A timepiece movement according to claim 12, characterised in that, The indicator (4) is a date ring comprising an internal toothed portion (5).

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

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