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

Abstract

To provide a mechanism for driving a jumping indicator.SOLUTION: A mechanism 6 for driving an indicator 4 in jumps includes: a wheel platform 8 having a first rotation axis 20; a driving finger 12 for driving the indicator 4; a spring 16; a rigid support 10 rotatable about the first rotation axis 20 to the wheel platform 8; and a lever 26 mounted on the rigid support 10 so as to be rotatable about a second rotation axis 22 apart from the first rotation axis 20, and forming the driving finger. The mechanism 6 limits rotation of the lever 26 in a first direction when the spring 16 is being loaded and the indicator 4 is making its next jump, the lever 26 being able to rotate in the opposite direction to the first direction, thus allowing the driving finger 12 to radially retract towards the first rotation axis under an action of a radial force exerted on the driving finger 12.SELECTED DRAWING: Figure 6A

Description

Technical Field

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

Background Art

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

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

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

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

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

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

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

[0009] Specifically, the drive mechanism is intended to enable the indicator to be quickly corrected by another specific mechanism characteristic of clock movements by means of additional torque generated by the presence of the drive mechanism during the passage of one tooth or the successive passage of a plurality of teeth of the outer flank of the drive finger of the indicator, this torque being minimal and not including sudden variations.

[0010] For this purpose, the present invention relates to a clock movement provided with an indicator, the clock movement comprising a mechanism for driving this indicator in jumps. The mechanism includes a wheel platform defining a first axis of rotation, a drive finger for driving the indicator, and a spring formed by a first end, a coil and a second end. The first end is attached so as to rotate together with the wheel platform, and the second end is attached so as to rotate together with the drive finger between at least the load of the spring prior to the jump by the indicator and the driving of the indicator by the mechanism during this jump. The mechanism includes a rigid support rotatable about the first axis of rotation relative to the wheel platform, and a lever mounted on the rigid support so as to be rotatable about a second axis of rotation remote from the first axis of rotation. The second axis of rotation is located at the first end of the lever, and the drive finger is formed on the side of its second end by this lever. The mechanism includes a first stop integral with the rigid support, the first stop restricting the rotation of the lever in a first direction corresponding to the direction in which the finger moves radially away from the first axis of rotation. The lever is arranged so as to be able to abut against the first stop at least when the spring (16) is under load before the indicator jumps, and to be able to rotate in a second direction opposite to the first direction, thereby allowing the drive finger to be radially retracted towards the first axis of rotation under the action of the force exerted on this drive finger, this force having a radially increasing component.

[0011] When the spring is under load, the first stop enables a constant radial distance to be maintained between the contact point of the drive finger on the teeth of the indicator and the first axis of rotation (central axis of rotation) of the mechanism. In contrast to the prior art, the action of the lever remains constant and the mechanism is more efficient.

[0012] In certain alternative embodiments, the indicator is a date indicator including teeth. In particular, the indicator is a date ring including internal teeth so as to be rotatably driven by the mechanism.

[0013] Thanks to the drive finger that is not integral with the rigid support but is rotatable about a second axis of rotation defined by the rigid support and remote from the first axis of rotation of the wheel platform and the rigid support, under the action of the force exerted by the indicator on this drive finger, the radial retraction of the drive finger in the direction of the first axis of rotation is in this case obtained by the rotation of the lever without radial displacement of the rigid support. This lever can be relatively lightweight and exhibit relatively low friction during rotation. That is, the couple added by the user by quickly correcting the indicator in the intended driving direction via a modification device other than the mechanism, or by correcting the time passing midnight in the counterclockwise direction (generating rotation of the wheel platform in the direction opposite to the driving direction), especially in the case of a calendar indicator, is relatively weak, and it is less noticeable than in the prior art for the drive finger, which mainly retracts radially with respect to the central axis, to pass through the indicator teeth.

[0014] Second, since the elastic deformation of the spring can be smaller than in the prior art, the stress generated in the spring is reduced, which is advantageous for sizing the spring. This is due to the rotation of the lever about the second axis, where the drive finger moves mainly towards the first axis of rotation. The spring necessarily undergoes a radial elastic deformation due to the radial retraction of the drive finger and thus the radial retraction of the second end of this spring. However, the angular deformation of the spring resulting from the couple applied to this second end can be much smaller than in the case of the prior art mechanism. Advantageously, the interaction of the teeth with the finger applies a force to the rigid support via the lever only, and thus at a second axis of rotation offset from the central axis of rotation. The direction of the force applied at the second axis, which results from the teeth of the indicator pushing against the outer flank of the drive finger, generates a torque in the rigid support that tends to rotate the rigid support, but this torque is weaker than that of the prior art. Considering the stiffness of the spring (which is necessary to store energy during normal driving of the indicator), the lever can rotate relative to the rigid support under the action of the teeth pushing against the outer flank of the drive finger, but this rigid support does not need to rotate relative to the wheel platform. That is, it can be seen that the spring mainly undergoes a radial elastic deformation due to the retraction of the drive finger by rotation about the second axis of rotation, which is away from the first axis of rotation. That is, with the drive mechanism of the present invention, the same retraction of the finger as in the prior art is allowed during correction, but the elastic deformation of the spring generated is smaller compared to the prior art mechanism where the spring undergoes a significant angular deformation in addition to the radial deformation.

[0015] The benefits of the present invention described above are significantly obtained in an advantageous alternative embodiment. Here, the outer flank of the drive finger is arched, and this arched outer flank has a radial dimension with respect to the first axis of rotation while the lever is in contact with the first stop. This radial dimension monotonically increases as it approaches the drive flank of the drive finger so as to press against the lateral flanks of the teeth of the tooth during the increment of the indicator at the jump.

[0016] According to an advantageous alternative embodiment, the spring and the lever are arranged such that the lever abuts against the first stop even when the spring is not subject to angular stress.

[0017] According to the main embodiment, the rigid support includes a plate forming the first stop. Specifically, the rigid support is constituted by such a plate.

[0018] According to a preferred embodiment, the mechanism is arranged such that when a load is applied, the spring contracts so as to be able to generate a jump in the spring, particularly a semi-instantaneous jump of the indicator. By contracting the spring, it is possible to obtain a constant radius for applying the driving force of the finger to the teeth of the indicator with which the finger abuts, and thus to optimize the driving torque required to drive the indicator and, in turn, to cause the indicator to jump.

[0019] According to an advantageous alternative embodiment, when the contracted coil is stressed as a result of the spring load, the angular displacement of the second end of the spring with respect to the wheel platform, and thus the angular displacement of the drive finger, is limited by a second stop defining an angular stop attached to rotate together with the wheel platform. The indicator and the mechanism are arranged such that after the angular displacement is stopped by the second stop and thus corresponds to a determined angular distance, the jump by the indicator takes place at the end of the spring load preceding this jump in normal operation.

[0020] The present invention further relates to a wristwatch incorporating the movement according to the present invention.

Brief Description of the Drawings

[0021] The objects, advantages and features of the present invention will be described in detail below with the aid of the accompanying drawings given as non-limiting examples.

[0022]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6A

Figure 6B

Figure 6C

Figure 6D

Figure 7A

Figure 7B

Figure 8A

Figure 8B

DETAILED DESCRIPTION OF THE INVENTION

[0023] With reference to the accompanying drawings, an advantageous embodiment of a mechanism for driving an indicator by a jump, particularly a half-instantaneous jump, will be described. Specifically, with reference to FIGS. 6A to 8B, the operation of a timepiece movement according to the present invention incorporating such a driving mechanism will be described.

[0024] The mechanism 6 for driving the jump indicator 4 includes a wheel platform 8 that rotates about a first rotation axis 20, a drive finger 12 that drives the indicator, and a spring 16. In a main alternative embodiment, the indicator is a date indicator, specifically a date ring that includes internal teeth 5. In other specific alternative embodiments given as non-limiting examples, the indicator is, for example, a minutes, hours, days, months indicator. The spring 16 is formed by a first end 17, a coil 18, and a second end 19. The first end is attached to the wheel platform that rotates together, and the second end is attached to the drive finger 12 that rotates together, between each load of the spring 16 prior to at least the jump by the indicator 4 and during the driving of the indicator by the mechanism during this jump. The first end 17 of the spring is connected to a central portion 24 that is attached to the wheel platform 8 so as to rotate together. Preferably, the spring and the central portion form one and the same part. The mechanism 6 includes a rigid support 10 that is rotatable about a first rotation axis with respect to the wheel platform, and a lever 26 that is mounted to the rigid support so as to be rotatable about a second rotation axis 22 that is remote from the first rotation axis 20.

[0025] The second rotation axis 22 is located at the first end of the lever and forms the drive finger on the side of its second end. Specifically, the lever has, at its first end, a circular stud 34 that is inserted into a hole 33 made in the rigid support. The lever is rotatable about the rotation axis 22 defined by this hole 33, and in particular, during rapid date correction or during a predetermined counterclockwise correction of the time passing midnight, as detailed below, the drive finger 12 is allowed to retract.

[0026] The mechanism 6 includes a central hub 32 that defines a shaft that passes through the central hole of the rigid support and guides the rigid support to be rotatable with respect to the wheel platform 8. The rigid support 10 and the central portion 24 are driven to the central hub 32.

[0027] Typically, the drive mechanism includes a first stop integral with the rigid support, the first stop restricting rotation of the lever in a first direction corresponding to the direction in which the finger moves radially away from the first axis of rotation 20. The lever is arranged to abut against the first stop and to be rotatable in a second direction opposite to the first direction, at least when the spring is loaded before the indicator jumps and preferably also when the indicator is driven during this jump. Thereby, under the action of the tangential component of the force exerted on this drive finger by the teeth of the indicator during adjustment, the drive finger retreats towards the first axis of rotation 20. Preferably, the spring and the lever are arranged such that the lever also abuts against the first stop even when the spring is not subject to angular stress. According to a main alternative embodiment, the rigid support includes a plate forming the first stop. According to the advantageous alternative embodiment shown in the figures, the rigid support is the plate 10.

[0028] According to the specific alternative embodiment shown in the figures, the lever 26 is formed by an arm 36 and a drive finger 12. The arm has a first height and is arranged at least partially between the wheel platform and the plate. The drive finger 12 has a second height H in the thick portion defining the drive flank 14. The drive flank 14 is intended to abut against the teeth of the tooth portion 5 associated with the indicator 4 (from FIGS. 6A to 8B) when the indicator is driven by the mechanism 6. The second height H is greater than the first height, and the thick portion of the drive finger is not laminated on the plate for any useful angular position of the lever, and this thick portion extends axially so as to at least partially exceed the thickness of at least one region of the plate located above the arm. The drive flank 14 is substantially radially present with respect to the first axis of rotation 20 when the lever abuts against the first stop 30.

[0029] According to an advantageous alternative embodiment, the plate 10 has a lateral surface, and a substantially radial region thereof defines a first stop 30. The drive finger 12 has a second height H over its entire extent within the plane of the teeth 5, and its rear upper part is arranged so as to be able to abut against the first stop 30 at least whenever the spring is loaded. As a result, the drive finger 12 is held in a fixed angular position relative to the second axis of rotation and thus in a fixed position relative to the first axis of rotation. Specifically, the rear upper part defines a stop surface 15 which, in cooperation with the first stop 30, limits the rotation of the lever in the first rotational direction. This stop surface 15 abuts against the first stop 30 each time the indicator jumps, i.e., the date jumps when the time display indicates midnight, at least after the spring 16 has been loaded.

[0030] In the first alternative embodiment shown in FIGS. 1 to 3, the plate 10 has an overall circular outer shape with a lateral cavity 38. The lateral cavity 38 is configured to allow the drive finger 12 to enter and thus retract when the teeth pass along the outer flank 13 of this drive finger, with most of the spring 16 always covered by the plate. In the second alternative embodiment shown in FIG. 5, the plate 10A of the mechanism 6A includes: a central part defining a central hole; a projection 58 covering a part of the spring 16 on the side of its second end 19 and holding it within the general plane of the spring between the wheel platform 8 and the plate 10A; and a part in the form of an annular sector extending radially from the central part, defining a first stop 30 at a first angular end and defining a hole 33 for the stud 34 of the lever 16 on the side of a second angular end.

[0031] In the illustrated alternative embodiment, the drive finger 12 has an arcuate outer flange 13. At least one tooth 5 of the teeth 5 of the indicator 4 can press against the arcuate outer flange 13 during rapid modification of the indicator using a modification device other than the mechanism. The arcuate outer flange has a dimension radial to the first axis of rotation 20 when the lever is in contact with the first stop 30. This dimension increases monotonically as it approaches the drive flange 14.

[0032] According to an advantageous alternative embodiment also shown in the figure, the lever 26 has a recess 42 with a lateral opening on the side of the spring 16 in an inner portion 46 extending alongside the drive finger 12. The second end 19 of the spring 16 is extended by a member 40 that connects to the lever 26. This connecting member 40 is rigid and is configured to be able to penetrate at least partially into the recess 42. Thereby, it is allowed for the spring to apply a driving couple to the rigid support 10 and the lever 26, and thereafter, it is allowed for the drive finger 12 to drive the indicator 4.

[0033] Preferably, the connecting member 40 is configured to be able to at least partially penetrate into the recess 42 through the side opening of this recess. Specifically, the recess 42 has a side surface 52 that is obliquely oriented in the rotational direction 50 of the wheel platform 8. In this rotational direction 50, the indicator 4 is intended to be driven radially, driven with respect to the central rotation axis 20, and driven to penetrate through the center of this side surface. The connecting member 40 has a side flange 54 facing the side surface 52, and this side flange is also obliquely inclined in the same direction as the side surface with respect to the central rotation axis 20, and at least partially abuts against this side surface when the indicator is driven. The outer surface and the outer flange are relatively long. This special feature ensures that the connecting member is firmly held in the recess as soon as the spring 16 contracts. Specifically, the contact point or contact zone of the recess where the spring force is exerted through the connecting member does not change when the spring is under load. Furthermore, when the spring is under load, the connecting member 40 cannot rotate about itself in the rotational direction of the wheel platform.

[0034] The lever 26 preferably has a side lamp 48 at the front part of the inner part 46, and by rotating the plate 10 clockwise with respect to the wheel platform 8 from the angular position of this connecting member located upstream of this side lamp 48, the connecting member 40 can be connected to the lever 26, particularly to the drive finger, by inserting this connecting member into the recess 42.

[0035] The recess 42 is typically triangular in shape and gradually opens towards its side opening. The shape of the portion of the connecting member 40 inserted into the recess from the side opening substantially corresponds to the shape of the recess. With this configuration, advantageously, the connecting member can be easily inserted into the recess. However, a priori, even though the recess is intended to be relatively deep, this member would come out extremely easily in the event of an impact. However, the spring 16 is arranged such that when this spring is loaded, the connecting member is present at a short distance from the inner end 17 of the spring rigidly connected to the central portion 24. In this situation, the connecting member 40 does not come out of its recess even in the event of an impact. Further, when the drive finger does not interact with the teeth 5 of the indicator and the spring 16 is substantially relaxed, the connecting member 40 also cannot escape laterally from its recess in the event of an impact. That is, the mechanism 6 is arranged such that the connecting member cannot come out of the recess 42 even if the spring relaxes or is stressed when the spring is loaded before the indicator jumps.

[0036] Once inserted into the recess 42, the connecting member 40, although not necessarily essential, can be held in this recess by the radial force exerted outwardly on it with respect to the rotation center axis 20 by the spring 16. This radial force (more precisely, the radial component of the force exerted by the spring on the lever via the connecting member) is increased by the fact that when the date is changed rapidly or when the time is corrected counterclockwise past midnight, the drive finger and the connecting member are retracted / pulled in the direction of the rotation axis 20 via a clockwise rotation (the second rotation direction of the lever). Thus, even when the spring 16 is somewhat extended in such a situation, the connecting member is normally held in the recess in this way.

[0037] During rapid correction of the date or time in a counterclockwise direction including passage at midnight, when the drive finger 12 retracts due to clockwise rotation of the lever 26, the connecting finger moves towards the central portion 24 after a predetermined initial rotation of the lever, such that the connecting member can no longer escape from its recess. During the initial rotation, the spring 16 expands under a predetermined angular stress and theoretically may allow the connecting member to escape from its recess in the event of an impact. However, when the connecting member is substantially accelerated in the direction of the axis of rotation 20 of the wheel platform 8, the lever is subject to a predetermined couple. This couple causes rotation of this lever about its axis of rotation 22 and the drive finger follows the connecting member, so that the connecting member remains at least partially within its recess. If acceleration occurs in a direction substantially passing through the center of gravity of the lever and its axis of rotation 22, the connecting member 40 may be subject to movement out of the recess 42. However, the internal projection 44 of the spring can be configured to prevent the connecting member from completely escaping from its recess. Alternatively, and preferably, the rear portion of the connecting member can be configured to collide with a rigid portion integral with the wheel platform during correction before it can completely escape from its recess. In conclusion, the mechanism 6 is arranged such that the connecting member 40 remains within its recess 42 during normal operation, so that this connecting member always remains integral with the drive finger during normal operation and in most cases cannot, preferably cannot at all, escape from the recess during impact.

[0038] Preferably, the mechanism 6 is arranged such that when this spring is loaded, the spring 16 contracts so that the indicator can generate a jump. Preferably, when stress is applied to the coil 18 contracted as a result of the spring load, the angular displacement of the second end 19 of the spring 16 relative to the wheel platform 8, and thus of the drive finger 12 connected to the connecting member 40, is limited by the second stop 28 that defines an angular stop attached to rotate with the wheel platform 8. The indicator and the mechanism are arranged such that, in normal operation, at the end of the spring load preceding this jump, the angular displacement is stopped by the second stop and thus before corresponding to a determined angular distance α (see FIG. 6A), no jump by the indicator occurs.

[0039] In the illustrated alternative embodiment, the spring 16 includes an internal projection 44 arranged along the coil 18 on the side of its second end 19. This internal projection is arranged to abut against the second stop 28 (angular stop) and thus to end the spring load. Thereby, the indicator 4 then jumps to its next stable position, i.e., to the next date in the case of the date indicator.

[0040] Figures 6A to 8B show in detail the operation of the timepiece movement 2, and particularly of the mechanism 6 driving the date ring 4 incorporated in this timepiece movement. The central hub 32 is not shown in these figures so as not to clutter the drawing, but it is clear that it is necessary for the mechanism 6 to function.

[0041] Figures 6A to 6D show four consecutive states of the mechanism 6 driving the date ring 4 during a jump, particularly a semi-instantaneous jump. Figures 6A to 6D each show when this ring is driven to change to the next date at midnight, i.e., · the point in time when the drive finger 12 contacts the tooth 5a of the ring 4 and the spring 16 is substantially angularly relaxed (i.e., no angular stress is applied), · After the internal projection 44 of the spring has received the angular displacement α with respect to the wheel platform 8 and abuts against the angular stop 28 and once the loading of the spring 16 is finished, · During the date jump caused by the mechanical energy stored in the contracted spring being applied to the assembly, and · When the jump is finished and the date ring 4 has reached substantially the next stable position, mechanism 6 and date ring 4 are shown.

[0042] In a particular embodiment, it should be noted that in normal operation, a jump by the indicator occurs before the angular displacement of the spring is stopped by the angular stop 28. In such a case, the angular stop becomes a spring protection stop. In other particular embodiments, the drive mechanism does not have an angular stop. The spring contracts and the coils of this spring expand freely between the two ends of the spring during the loading period.

[0043] To prevent the teeth 5a of the indicator 4 from passing above or below the drive finger 12 when the indicator is driven, the height including the play between the wheel platform 8 and the lower side of the teeth 5 is always provided to remain between the lower height including the play and the upper height of the drive finger from the wheel platform. For this purpose, in an advantageous alternative embodiment, the lower height of the finger is smaller than the thickness of the teeth of the tooth part 5. Preferably, in a wristwatch incorporating the timepiece movement 2, the distance between the upper height of the finger and the dial covering the drive mechanism and the indicator is also designed to be smaller than the thickness of the teeth of the tooth part 5. The large height of the finger 12 can rise at least from the lower side of the spring 16 to above the plate 10 defining the upper surface of the mechanism 6, so that it is possible to easily prevent the teeth 5a from passing below or above the finger 12.

[0044] Figures 7A and 7B show the behavior of mechanism 6 during the rapid correction of date ring 4 by a control member operable by the user in a conventional manner. When the wheel platform 8 and the plate 10 are, for example, initially in the configuration shown in Figure 7A in the evening such that the finger 12 is positioned between the tooth 5a and the tooth 5b preceding it in the rotational direction 60, the finger 12 is in the path of the tooth 5b of the indicator. The ring 4 is intended to progress rapidly in the rotational direction 60 corresponding to the single rotational direction of the date ring. As shown in Figure 7B, as the ring 4 rotates, the tooth 5b of the tooth part 5 contacts the arcuate outer flank 13 of the finger 12 and gradually exerts a radial force on this finger. Thereby, the lever 26 rotates clockwise about its rotation axis 22, so that the finger 12 moves towards the central hub of the plate 10 and the finger retreats towards the rotation axis 20. This retreat is made possible by the configuration of the drive finger 12, the outer shape of the lateral cavity 38 provided in the plate 10, the arrangement of the spring 16 and the central part 24 to which it is attached, and the configuration of the internal projection 44. As can be seen in Figure 7B, as the tooth 5b passes, the finger 12 retreats, so this tooth is allowed to follow the outer flank 13 of the finger until this tooth projects at an angle beyond the finger.

[0045] As already explained, the interaction of the teeth 5 with the drive finger 12 applies a force to the plate 10 only via the lever 26 and thus at the second axis of rotation 22. The direction of the force applied at the second axis of rotation, which results from the indicator teeth 5a or 5b pressing against the outer flank 13 of the drive finger, generates a torque in the plate that tends to rotate the plate, but this torque is weaker than that of the prior art. Given the stiffness of the spring 16, the lever 26 can rotate relative to the plate under the action of the teeth pressing against the outer flank of the drive finger, without this rigid support rotating significantly relative to the wheel platform. As can be seen, the spring is mainly elastically deformed in the radial direction relative to the axis of rotation 20 due to the retraction of the drive finger 12 by rotation about the second axis of rotation 22 (the central axis of rotation of the mechanism), which is remote from the first axis of rotation 20. That is, the drive mechanism 6 allows the same retraction of the finger during modification as in the prior art, but the elastic deformation of the spring 16 that occurs is less than in the prior art mechanism where the spring undergoes a significant angular deformation in addition to the radial deformation. That is, the work that has to be done by the date ring 4 to allow the tooth 5b to pass through the drive finger 12 (in a plane perpendicular to the axes of rotation 20 and 22) during the correction of the problem is less than for a drive finger fixed to a plate having a similar outer shape, but in particular having an oblong hole through which a central shaft formed by a hub passes, as in the prior art.

[0046] As the finger 12 moves radially, the spring 16 contracts radially and the connecting member 40 approaches the central portion 24. It should be noted that the spring 16, or rather its coil 18, is also slightly expanded during the rapid correction of the date ring, simultaneously with the radial stress that the spring receives in the direction of the rotation axis of the wheel platform. However, considering the outer profile of the outer flank 13 of the finger 12 and the rotation of this finger in the direction of the rotation axis 20 (the first rotation axis at the center) described above, the stress of the expanding spring is relatively small, or even substantially zero depending on the configuration of the system. This is very advantageous for the design of the spring 16. The spring 16 can therefore be arranged to be as resilient as possible without the need to ensure that this spring behaves appropriately against significant expansion stress during the contraction that occurs when the indicator 4 is driven by the device 6.

[0047] Figures 8A and 8B show the behavior of the mechanism 6 during the correction of the time displayed by the timekeeping mechanism. Thereby, the wheel platform 8 is rotated counterclockwise past midnight. In this case, the date ring 4 remains stationary at its stable position when the time is corrected. The series of states of the mechanism 6 is the same as the series of states that occur during the rapid correction of the date display described above. When the assembly formed by the wheel platform 8, and thus the plate 10 and the lever 26, rotates in a direction opposite to the normal rotation direction (the direction corresponding to the clockwise direction of the time display), the arched outer flank 13 of the finger 12 abuts against the tooth 5a of the tooth portion 5 (Figure 8A). The plate 10 continues to rotate but rotates slightly slower than the wheel platform due to the slight expansion of the spring, at least in the initial stage. On the other hand, the drive finger moves radially towards the rotation axis 20 via the clockwise rotation of the lever 26 that deeply penetrates into the lateral cavity 38, so that while this finger retracts, the stationary tooth 5a extends along the outer flank 13 of the finger.

[0048] The mechanism 6 is configured to prevent blocking during rapid date correction or counterclockwise time correction.

[0049] The present invention further relates to a wristwatch comprising the timepiece movement 2 according to the present invention. This movement is incorporated into a case which further incorporates a dial arranged so as to be able to display data which varies over time by jumps, in particular the date.

Claims

1. A timepiece movement (2) including an indicator (4) and a mechanism (6) for driving this indicator by a jump, the mechanism including a wheel platform (8) rotating about a first rotation axis (20), 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 so as to rotate together with the wheel platform, and the second end being attached so as to rotate together with the drive finger at least between the load of the spring prior to the jump by the indicator and the drive of the indicator by the mechanism during this jump, characterized in that the mechanism (6) includes a rigid support (10) rotatable about the first rotation axis (20) relative to the wheel platform, and a lever (26) mounted on the rigid support so as to be rotatable about a second rotation axis (22) remote from the first rotation axis, the second rotation axis being located at a first end of the lever, the drive finger (12) being formed by the lever on a side of its second end, the mechanism (6) including a first stop (30) integral with the rigid support (10), the first stop (30) restricting the rotation of the lever in a first direction corresponding to the direction in which the drive finger moves radially away from the first rotation axis (20), the lever being arranged so as to abut against the first stop at least when the spring (16) is loaded, and so as to be rotatable in a second direction opposite to the first direction, thereby allowing the drive finger to be radially retracted towards the first rotation axis under the action of a force exerted on the drive finger, the force having a radially increasing component, a timepiece movement.

2. The timepiece movement according to claim 1, characterized in that the spring (16) and the lever (26) are arranged so that the lever also abuts against the first stop when the spring is not subjected to angular stress.

3. The timepiece movement according to claim 1 or 2, characterized in that the rigid support includes a plate (10) rotatably guided about the first rotation axis (20) by a shaft (32) attached so as to rotate together with the wheel platform. The plate forms the first stop (30).

4. The lever is formed by an arm (36) and the drive finger (12). The arm has a first height and is at least partially disposed between the wheel platform (8) and the plate (10). The drive finger has at least a second height (H) in a thick portion defining a drive flank (14) intended to abut against a tooth (5a) of a tooth portion (5) associated with the indicator (4) when the indicator is driven by the mechanism (6). The second height is greater than the first height. The thick portion of the drive finger is not laminated on the plate for any useful angular position of the lever, and this thick portion axially extends at least partially beyond the thickness of at least one region of the plate located above the arm. The timepiece movement according to claim 3, characterized in that

5. The timepiece movement according to claim 4, characterized in that the plate (10) has a lateral surface, one zone (30) of the lateral surface defining the first stop. The drive finger is arranged such that the upper rear portion of the thick portion of the drive finger abuts against the first stop (30) at least each time the spring is loaded. The drive finger is held in a fixed angular position with respect to the second rotation axis and thus in a fixed position with respect to the first rotation axis.

6. The timepiece movement according to claim 4, characterized in that the plate (10) has an overall circular outer shape with a lateral cavity (38). The lateral cavity (38) is configured to allow the drive finger (12) to enter and thus retract into this cavity when teeth (5a, 5b) pass along the outer flank (13) of the drive finger, with most of the spring (16) always covered by the plate.

7. The drive finger (12) has an arched outer flank (13), and at least one tooth (5a) of the tooth part (5) can press the arched outer flank (13) during rapid correction of the indicator using a correction device other than the mechanism, and the arched outer flank has a radial dimension that monotonically increases as it approaches the drive flank (14) with respect to the first rotation axis when the lever is in contact with the first stop (30). The timepiece movement according to claim 4, characterized in that.

8. The mechanism (6) is arranged such that the spring (16) contracts when loaded so that the indicator (4) can cause a jump. The timepiece movement according to claim 1 or 2, characterized in that.

9. The spring (16) includes an internal projection (44) arranged along the coil (18) on the side of its second end (19), and this internal projection, at the end of the spring load and before the indicator jumps, is arranged to abut against a second stop (28) that defines an angular stop attached to rotate together with the wheel platform (8). The timepiece movement according to claim 8, characterized in that.

10. The first end (17) of the spring (16) is connected to a central part (24) attached to rotate together with the wheel platform (8). The timepiece movement according to claim 1 or 2, characterized in that.

11. The lever (26) has a recess (42) with a lateral opening on the side of the drive finger and on the side of the spring (16), The second end (19) of the spring is extended by a member (40) connected to the lever (26), and this connecting member (40) is rigid and is configured to be able to at least partially penetrate into the recess through the lateral opening, so that the spring is allowed to apply a driving couple to the lever, and thus the drive finger is allowed to drive the indicator. The timepiece movement according to claim 1 or 2, characterized by the above.

12. The recess (42) has a lateral surface (52) that is obliquely oriented in the rotational direction (50) of the wheel platform (8), and the indicator is intended to be driven in the rotational direction (50) with respect to the radial direction with respect to the first rotation axis so as to pass through the center of this lateral surface. The connecting member (40) has a lateral flank (54) facing the lateral surface, and this lateral flank is also inclined obliquely with respect to the first rotation axis in the same direction as the lateral surface, and when the indicator is driven, it abuts at least partially against this lateral surface. The timepiece movement according to claim 11, characterized in that.

13. The timepiece movement according to claim 1 or 2, characterized in that the indicator (4) is a minute indicator, an hour indicator, a date indicator, a day-of-the-week indicator, or a month indicator.

14. The timepiece movement according to claim 13, characterized in that the indicator (4) is a date ring.

15. A wristwatch, characterized in that it includes the timepiece movement (2) according to claim 1 or 2.

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