ACTION MECHANISM FOR CLOCK

Description

[0001] The present invention relates to an actuation mechanism for a timepiece comprising a rocker mounted pivoting between a rest position and a fully tilted position, the rocker having an actuation arm splitting into two branches, one of the two branches being flexible, and the other branch being rigid, one end of the flexible branch being arranged to push a tooth of a star when the rocker pivots from its rest position to its fully tilted position, the arc-shaped trajectory of the end of the rigid branch remaining, for its part, always outside the head circle of the star, the flexible branch further comprising a backing area provided to bear against a bearing surface of the rigid branch when the rocker pivots from its rest position to its fully tilted position and that, consequently, the end of the flexible branch pushes the tooth of the star,The flexible arm comprises a proximal part oriented substantially radially with respect to the pivot axis of the rocker, and a second part which is oriented transversely with respect to the proximal part and separated from the latter by a bend. EARLIER ART

[0002] THE figures 1A et 1B The attached images show, as an example, the day corrector of an earlier calendar watch. As a reminder, a corrector is an actuation mechanism comprising a small button, most often recessed into the case of a timepiece, which is arranged to work with a star to correct one of the indications displayed by the timepiece. The watch wearer or a watchmaker can operate the corrector either with their finger or with a special tool called a "pusher." The corrector illustrated in both images figures 1A et 1B is generally referred to as 1. It takes the form of a rocker mounted to pivot around an axis (referenced 5). The rocker consists of an arm extending from the pivot axis 5 and dividing into three branches, each with a distal end. The first distal end is a button (referenced 3) that can be operated from outside the timepiece. The second end is designed to cooperate with a return spring (referenced 7) intended to return the corrector to its rest position. Finally, the third end is shaped like a beak (referenced 9) that is designed to cooperate with the teeth of a seven-pointed star (referenced 11). Typically, the star 11 could, for example, carry a day-of-the-week indicator (not shown). The position of the star 11 is indexed by a jumper spring (referenced 13). There figure 1A illustrates corrector 1 in its rest position, while the figure 1B the watch in a completely tilted position.

[0003] The operation of the illustrated correction mechanism is as follows. When the corrector 1 is in its rest position and the user presses button 3, this pivots the rocker arm against the return spring 7. As it pivots, the corrector's beak 9 engages one of the teeth of the star wheel 11, causing it to rotate. The rotation of the star wheel causes one of the teeth to lift the jump spring 13, which rises until the tip of its inclined arm has passed over the crest of the tooth and onto the opposite side. Once the inclined arm of the jump spring 13 has passed over the crest and is in a position to begin its descent on the opposite side of the tooth, the force exerted by the inclined arm on the crest of the tooth no longer opposes the rotation of the star wheel, but instead produces a torque that applies force to the star wheel in the direction in which it is already rotating.It will therefore be understood that the beak 9 does not need to guide the star's tooth over the entire distance between two consecutive indexed positions. It is sufficient that the angle over which the beak 9 actually guides the star's tooth is sufficient to allow the jumper 13 to pass over the tip of the tooth.

[0004] Driven by the jump spring 13, the star 11 continues its rotation until the next tooth abuts against the rear face of the corrector's beak 1, as illustrated in the figure 1B It can be seen that in the configuration shown, the corrector 1 and the star 11 lock each other in place by a buttressing action. Then, when the user releases the button 3, the corrector 1 is returned to its rest position by the spring 7. However, in order to return to the rest position, the rear face of the beak 9 must first slightly push back the tooth that is locking it. It will be understood that the rear face of the beak pushes the tooth far enough back to allow the beak to slide past its crest, but not far enough so that the jump spring 13 does not risk returning to the first side of the tooth whose crest it has passed. Once the corrector's beak 9 has moved back far enough to disengage from the teeth of the star 11, the latter is free to rotate until the two inclined ends of the jump spring simultaneously bear against the crests of two teeth, as shown in the figure 1A . Star 11 then finds itself in its new stable position, after having advanced exactly one step.

[0005] The use of spell checkers similar to the one illustrated in the figures 1A et 1B It is not without its problems. First, it's important to remember that it's generally not recommended to use the correctors on a calendar watch between 8:30 PM and 3:30 AM. This is because the date indicator's incrementation by the movement of a calendar watch typically occurs during a period that can last several hours and is centered around midnight. Under these conditions, if a user decides to operate the corrector on a date indicator during one of these periods, the opposing forces exerted by the calendar's drive mechanism, on the one hand, and by the corrector, on the other, could cause a part of the mechanism to break or result in a phase shift.

[0006] To avoid this type of problem, the calendar of certain well-known complicated watches is equipped with one-way drive mechanisms. These drive mechanisms, which most often function like ratchets, are designed to disengage automatically when the user advances the corrector of the star they are incrementing. One-way drive mechanisms effectively prevent breakage when a user advances a corrector "around midnight." However, their implementation also comes with several drawbacks. In particular, disengaging a drive mechanism causes it to lose its index from the teeth with which it engages. Furthermore, one-way drive mechanisms are designed to disengage only when a corrector advances a star.Under these conditions, if the corrector cannot then return to its rest position without pushing the star it has just incremented back (as is notably the case with the corrector of the . figures 1A et 1B ) there remains a problem.

[0007] Indeed, during the incrementation of the stars in a calendar mechanism, the drive elements prevent any backward rotation of the stars. It should be noted that blocking a star 11 does not prevent the corrector 1 for that star from being activated once. However, the presence of the tooth of star 11, which is pressed against the rear face of the beak 9 (cf. figure 1B The corrector 1 remains in its fully tilted position, even after its button 3 has been released. Therefore, corrector 1 is prevented from returning to its resting position while the star 11 is being incremented. It is clear that such a situation is undesirable.

[0008] Furthermore, actuating mechanisms for watch parts are known that correspond to the definition given above in the introduction. In particular, patent document EP 3 489 766 A1 describes a corrector whose actuating arm splits into two branches, one flexible and the other rigid. One end of the flexible branch is arranged to push a tooth of a star wheel when the actuating arm pivots from its rest position to its tilted position. The trajectory of the rigid branch, however, always remains outside the path of the star wheel teeth. In this known corrector, the flexible branch has two bends that divide it into three parts.First, a proximal portion is positioned on the rear side of the actuating arm when the corrector pivots from its rest position to its tilted position, and is oriented substantially radially with respect to the pivot axis. Second, a second portion is oriented transversely with respect to the proximal portion so that it covers the end of the rigid arm. Finally, a third portion is folded back towards the pivot axis of the actuating arm, so that it is also oriented substantially radially with respect to this axis. This third portion is located on the front side of the actuating arm when the corrector pivots from its rest position to its tilted position.The bend between the second and third sections of the flexible arm forms the end of the flexible arm, which is designed to push a tooth of the star when the rocker pivots from its rest position to its tilted position. The third section of the flexible arm has a support area designed to bear against a bearing surface on the rigid arm when the end of the flexible arm pushes the tooth of the star. The bearing surface is formed on the side of the rigid arm that faces forward when the rocker pivots from its rest position to its tilted position.

[0009] The prior art corrector just described has the advantage of being able to return to its resting position without pushing the star backward. However, its use can present difficulties. Indeed, to avoid unduly increasing the thickness of the mechanism, the height of the corrector's actuating arm is generally limited. Furthermore, the flexible arm must be thin to exhibit the required elasticity. Under these conditions, it is understandable that the flexible arm is susceptible to torsional deformation when subjected to torque.

[0010] We have also seen that the proximal part of the flexible arm is positioned on the rear side of the actuating arm, while its third part is positioned on the front side. The proximal and third parts are essentially parallel, and the distance between them is relatively large. Under these conditions, any twisting, even slight, of the proximal part around its axis causes the third part to shift upwards or downwards, so that the entire third part is liable to move out of the pivot plane of the actuating arm. We have also seen that the end of the flexible arm designed to push a tooth of the star corresponds to the bend between the second and third parts.It will therefore be understood that if the third part moves out of the pivot plane, the end formed by the elbow risks passing above or below the teeth of the star, thus compromising the proper functioning of the corrector.

[0011] Patent document EP 3 584 643 A1 describes an instantaneous control device for a date display in a timepiece, comprising a trigger and drive lever for the date display. The lever includes a retractable drive finger formed by a flexible part mounted on, or formed as a single piece with, the lever. The drive finger is equipped with a stop cooperating with a limiting shoulder arranged on the lever so as to restrict the pivoting of the drive finger to a desired angular range when the drive finger drives the date display. A disadvantage of this device is that, when the lever drives the date display, a significant component of the force exerted by the finger against the driven tooth is not oriented along the longitudinal axis of the flexible part, which may cause deformation of the latter. BRIEF SUMMARY OF THE INVENTION

[0012] One object of the present invention is to overcome the drawbacks of the prior art just described. The present invention achieves this object, as well as others, by providing an actuation mechanism that conforms to the attached claim 1.

[0013] According to the invention, the proximal portion of the flexible arm is located on the front side of the actuating arm when the rocker pivots from its rest position to its fully tilted position. Furthermore, it is oriented substantially radially with respect to the pivot axis of the rocker. In addition, the contact area of ​​the flexible arm is located on the second portion, and the bearing surface against which the contact area is arranged to bear is formed by a straight edge of the end of the rigid arm, this straight edge being oriented substantially tangentially to the arc-shaped path followed by the end of the rigid arm when the rocker pivots. Finally, the end of the flexible arm that is arranged to push a tooth of the star is formed by the outer side of the bend that separates the proximal portion from the second portion of the flexible arm.

[0014] One advantage of the invention is that the end of the flexible arm, which is arranged to push a tooth of the star, is substantially in line with the proximal part. Under these conditions, a twist of the proximal part around its axis does not risk causing said end to shift out of the path of the star's teeth. BRIEF DESCRIPTION OF THE FIGURES

[0015] Other features and advantages of the present invention will become apparent from the following description, given solely by way of non-limiting example, and made with reference to the accompanying drawings in which: THE figures 1A et 1B are schematic plan views of a prior art corrector; the figures 2 et 3 are schematic plan views of a corrector corresponding to a particular embodiment of the actuation mechanism of the invention, the corrector being shown at two successive instants during its pivoting from its rest position towards its fully tilted position; figure 4 is a schematic plan view of the corrector of figures 2 et 3 at a particular moment of its return to rest position after having set the rotating star in motion. DETAILED DESCRIPTION OF IMPLEMENTATION METHODS

[0016] Schematic plan views of figures 2 à 4 The attached figures show an actuation mechanism for a timepiece, which constitutes an exemplary embodiment of the invention. The actuation mechanism shown in the figures is designed to be operated by a user to correct an indication displayed by the timepiece. Such an actuation mechanism, controllable from outside the timepiece, is known as a "corrector." It is important to note, however, that not all the actuation mechanisms that constitute the various embodiments of the invention are correctors. These embodiments also include actuation mechanisms that function as automatic drive elements for a display mechanism (a calendar mechanism, for example) driven by the movement of a timepiece.

[0017] The corrector represented in the figures 2 à 4 includes a control mechanism that can be operated manually from outside the timepiece (symbolized by an arrow referenced 15 in the figures 2 et 3 ), a rocker arm (usually referenced as 17), and a return spring (referenced as 19). Besides the operating mechanism itself, the figures also show a star wheel (referenced as 21) with seven teeth. In this example, the star wheel could carry a day-of-the-week indicator (not shown). The position of the star wheel 21 is indexed by a jump spring (referenced as 23) which is returned against the teeth of the star wheel.

[0018] The corrector's rocker arm is mounted to pivot around an axis (referenced 25), and it can be seen that, in the illustrated example, its single arm 17 extends from the pivot axis, successively forming two bends in opposite directions (in the plan views of the figures 2 à 4 (The first elbow turns left and the second turns right). The two elbows subdivide the arm 17 into three sections. A first radially oriented section runs from axis 25 to the first elbow. Next, a second section is oriented obliquely to the first section and runs from the first to the second elbow. Finally, a third section extends beyond the second elbow and is also oriented substantially radially to the pivot axis 25. The first elbow also has a bulge (referenced 27) with which the control member 15 is arranged to cooperate. Finally, the third section of the arm 17 has a bifurcation from which the arm splits into two branches spaced apart. One of the two branches (referenced 29) is flexible, while the other branch (referenced 31) is rigid.

[0019] It can be seen that the flexible arm 29 comprises a proximal elastic portion (referenced 33) which is oriented substantially radially with respect to the pivot axis 25 of the rocker, and a distal portion consisting of a rigid shoe (referenced 35) which extends opposite the end of the rigid arm 31, transversely with respect to the proximal portion. The junction between the proximal portion 33 and the shoe 35 forms an acute bend. As shown in particular by the figure 2 , the proximal part 33 of the flexible branch 29 is approximately straight. It can also be observed that, when the flexible branch 29 is not constrained (as is the case in the figure 2 ), the end of branch 29 that is furthest from the pivot axis 25 is formed by the tip of the elbow (referenced 37). Now referring to the figure 3 , we can see that the tip 37 of the elbow is arranged to push back a tooth of the star 21 when the rocker pivots from its rest position (represented in the figure 2 ) towards its fully tilted position (in other words, pivots counterclockwise as shown in the figures). Since the rigid arm 31 is significantly shorter than the flexible arm 29, its arc-shaped trajectory never intersects the teeth of the star 21.

[0020] The rigid arm 31 and the proximal part 33 of the flexible arm 29 are arranged relative to each other such that the rigid arm 31 lies behind the flexible arm 29 when the rocker pivots counterclockwise. Always referring to the figure 3 It can be seen that the end of the rigid arm 31 is a straight edge that serves as a bearing surface (referenced as 39) and is oriented tangentially to its arc-shaped trajectory. Furthermore, the shoe 35 of the flexible arm 29 has a contact area that bears against the bearing surface 39 when the tip 37 of the flexible arm's elbow 29 pushes against a tooth of the star 21 against the holding torque generated by the spring 23. Indeed, in this situation, the tooth of the star 21 exerts a reaction force on the tip 37 of the flexible arm. Since the reaction force is oriented substantially perpendicular to the orientation of the elastic proximal portion 33 of the flexible arm, the latter bends under the applied stress.Within the limits of small deformations, the bending of the proximal part 33 of the branch 29 results in a rotation of the end of the proximal part as well as of the shoe 35 (in a direction corresponding to the clockwise direction as shown in the figures). This rotation causes the portion of the edge of the shoe 35 that is opposite the end of the rigid branch 31 (in other words, the abutment zone) to come against this end, as shown in the figure. figure 3 When the rocker arm 17 is in the configuration shown in the figure 3 The shoe 35 cannot rotate clockwise relative to the rigid arm, which allows the tip 37 to behave as if it were fixed to the latter, despite the resistance opposed by the tooth of the star 21. It should be noted that the flexible arm 29 must be sufficiently flexible so that the force required to bring the shoe 35 against the end of the rigid arm 31 is less than the force required to lift the jump spring 23.

[0021] The characteristics just described, concerning the corrector in this example, allow it to function as follows. When the corrector is in its rest position (represented by the figure 2 ) and that the user operates the control element 15 from outside the timepiece, they pivot the rocker against the return spring 19. By pivoting, the tip 37 of the flexible arm 29 encounters one of the teeth of the star 21. The reaction force exerted by the tooth on the flexible arm 29 causes its elastic proximal part 33 to flex until the contact area of ​​the shoe 35 abuts against the bearing surface at the end 39 of the rigid arm 31. The situation then corresponds to that shown in the figure 3 The tip 37 then acts as an extension of the rigid arm 31, enabling it to drive the star 21 in rotation. The rotation of the star causes one of the teeth to lift the jump spring 23, which rises until the tip of its inclined end has passed over the crest of the tooth and onto the other side. As soon as the inclined end of the jump spring 23 is thus in position to begin its descent on the opposite side of the tooth, the force that the inclined end exerts on the crest of the tooth no longer opposes the rotation of the star, but instead produces a torque that drives the star 21 in the direction in which it is already being driven. The disappearance of the couple which until then opposed the rotation of the star 21 allows the elastic proximal part 33 of the flexible branch 29 to straighten itself by moving the shoe 35 away from the end of the rigid branch 31.

[0022] When, after actuating the corrector, the user releases the control member 15, the corrector's rocker arm is returned to its rest position by the spring 19. However, the path that the tip 37 must take to return to its rest position is now blocked by the tooth of the star 21 that follows the one the corrector has just pushed forward. According to the present invention, the corrector's actuating arm 17 is capable of returning to its rest position, even when the automatic incrementing mechanism of the star 21 blocks its rearward rotation. Indeed, it is possible to move the tip 37 and the shoe 35 away from the path of the star 21's teeth by flexing the proximal part 33 of the flexible arm 29 in the direction shown in the figure. figure 4The flexion of the proximal portion 33 of the arm 29 in the direction shown in this figure results in a rotation of the tip of the proximal portion 33 as well as of the shoe 35 (in a direction corresponding to the counterclockwise direction as shown in the figures). It will be understood that the pressure of the tooth's apex on the shoe 35 gradually flexes the proximal portion 33 of the flexible arm 29 until the tip 37 has passed the tooth. This behavior is made possible by the fact that the force required to flex the flexible arm 29 is less than the force required to lift the spring 23 high enough for the tip of its inclined spring to pass over the apex of a tooth. Then, as soon as the tip 37 has passed the tooth, the elastic proximal portion 33 of the flexible arm 29 is free to straighten.

[0023] It will also be understood that various modifications and / or improvements obvious to a person skilled in the art can be made to the embodiments which are the subject of this description without departing from the scope of the present invention as defined by the attached claims.

Claims

1. Actuating mechanism for a timepiece comprising a lever arm mounted so as to pivot between a rest position and completely tipped-over position, the lever arm having an actuating arm (17) splitting into two branches (29, 31), one of the two branches being flexible and the other branch being rigid, one end (37) of the flexible branch (29) being arranged to come to push one tooth of a star wheel (21) when the lever arm pivots from its rest position to its completely tipped-over position, the path in the form of an arc of a circle of the end of the rigid branch (31) remaining, for its part, always outside of the tip circle of the star wheel (21), the flexible branch (29) further having a bearing zone provided to come to abut against an abutment surface (39) on the rigid branch (31) when the lever arm pivots from its rest position to its completely tipped-over position and when, therefore, the end (37) of the flexible branch (29) pushes the tooth of the star wheel (21), the flexible branch having a proximal part (33) which is oriented substantially radially with respect to the pivot spindle (25) of the lever arm, and having a second part (35) which is oriented transversely with respect to the proximal part (33) and separated therefrom by an elbow; characterised in that the proximal part (33) of the flexible branch (29) is on the front side of the actuating arm (17) when the lever arm pivots from its rest position to its completely tipped-over position, in that the end (37) of the flexible branch (29) is formed by the outer side of the elbow which separates the proximal part (33) from the second part (35), in that the bearing zone of the flexible branch (29) is located on the second part (35) of the flexible branch, and in that the rigid branch has, at its end, a straight edge oriented tangentially to its path in the form of an arc of a circle, the abutment surface (39) against which the bearing zone is arranged to come to abut being formed by the straight edge.

2. Actuating mechanism for a timepiece as claimed in claim 1, characterised in that it comprises a control member (15) which can be actuated manually from outside of the timepiece, and in that the arm (17) is arranged to cooperate with the control member (15) to bring the lever arm into the completely tipped-over position when the control member (15) is actuated from outside of the timepiece.

3. Actuating mechanism for a timepiece as claimed in claim 1 or 2, characterised in that it comprises a spring (19) arranged to return the lever arm to its rest position.

4. Actuating mechanism for a timepiece as claimed in any one of claims 1, 2 and 3, characterised in that the timepiece has indexing means (23) for the star wheel (21), the indexing means (23) being arranged to produce a holding torque oriented so as to return the star wheel (21) to an indexed angular position when the star wheel moves away from said angular position, and in that the flexible branch (29) has sufficient stiffness to enable it to push one of the teeth of the toothed arrangement of the star wheel (21) with enough force to overcome the holding torque when the bearing zone of the flexible branch (29) abuts against the abutment surface (39).

5. Actuating mechanism for a timepiece as claimed in any one of the preceding claims, characterised in that the outer edge of the elbow which separates the proximal part (33) from the second part (35) forms a tip (37) which forms the end of the flexible branch (29).

6. Actuating mechanism for a timepiece as claimed in claim 5, characterised in that the outer edge of the elbow forms an acute angle at the tip (37).

7. Actuating mechanism for a timepiece as claimed in any one of the preceding claims, characterised in that the proximal part (33) of the flexible branch (29) comprises a leaf spring.