EP3882716B1 - Timepiece including a toothed moving part indexed by a spring - Google Patents

Description

The present invention relates to a timepiece comprising a toothed mobile, an indexing device comprising a jumper and elastic means arranged to return the head of the jumper against the toothing of the toothed mobile so as to index the latter, and a time-setting which is movable in translation between a neutral position and at least a first pulled-out position in which it is possible to actuate the toothed wheel set in rotation by rotating the time-setting stem.

PRIOR ART

Many timepieces are known which correspond to the above definition. By way of non-limiting example, the mobile indexed by a jumper may be a jumping display member, in particular a member for displaying the date or the day of the week. Unlike other manually actuated control devices, such as pushpieces for example, a time-setting stem does not impose any constraints as to the manner in which it is actuated. It transmits all the forces to which it is subjected, regardless of their duration and intensity. This feature is not entirely devoid of disadvantages. Indeed, a user wishing to manually adjust the position of the indexed mobile, using the time-setting stem, has no marker allowing him to measure his effort. It is therefore very difficult for him, for example, to drive the indexed mobile through a determined number of steps.

Traditionally, many calendar watches offer the possibility of correcting the time indicated by the hands at will by manually rotating the winding/time-setting crown, forwards or backwards, in position pulled from the rod. Each time during the correction, the time indicated by the hands passes through midnight, the date indicator organ pivots one step in the corresponding direction. This has the effect of incrementing or decrementing the indication of the date. The applicant was able to observe however that, during a correction, the passage of the hour hand through midnight sometimes caused multiple jumps of the date indicator organ. In fact, when setting the time, the hour and minute hands move much faster than during the normal running of the watch. Under these conditions, when they pass through midnight, the hands activate the date indicator organ with great energy. The momentum that animates the date indicator member when the date is incremented can even be such that it performs several consecutive jumps before coming to a standstill.

The document FR 2 081 855 A7 discloses a timepiece in which a correction system acts on a jumper spring by changing the tension of said spring.

BRIEF DESCRIPTION OF THE INVENTION

An object of the present invention is to remedy the drawbacks of the prior art which have just been explained. The present invention achieves this and other objects by providing a timepiece which is in accordance with appended claim 1.

According to the invention, the timepiece comprises a braking system comprising a spring integral with the jumper and a bearing surface fixed to the spring, and also comprising a switch arm arranged to be controlled by the time, the braking system being arranged to be in an inactive state, in which the switch arm does not interact with the bearing surface, when the time-setting stem is in the neutral position, and to be in an active state, in which the commutator arm deforms the spring by exerting a force on the bearing surface, when the time-setting stem is in the said first pulled-out position.

It is known that a spring subjected to stresses deforms, and that the resulting deformation is a function of these stresses. Conversely, a a spring which is kept deformed exerts on each of its points of support a force which is a function of its deformation. The head of the jumper comes to rest against the toothing of the toothed mobile, and the jumper is also integral with the spring of the braking system. Under these conditions, it can be understood that the intensity of the force exerted by the jumper head on the teeth depends on the deformation of the spring of the braking system. Moreover, in a manner known per se, the force exerted by the head of the jumper on the toothing is at the origin of a resistive torque which opposes the rotation of the toothed mobile. Thus, the deformation of the spring, which is caused by the switch arm in the active state of the braking system, increases said resistive torque. On the other hand, the braking system has no influence on the resistive torque when it is in the inactive state.

BRIEF DESCRIPTION OF FIGURES

• les figures 1, 2A et 3 sont trois vues en plan montrant le dispositif d'indexation, la tige de mise à l'heure et le système de freinage d'une pièce d'horlogerie qui est conforme à un premier mode de réalisation particulier, les trois vues montrant respectivement la tige de mise à l'heure en position neutre, en première position tirée et en deuxième position tirée;
• la figure 2B est une vue en plan semblable à celle de la figure 2A, et qui montre encore le mobile denté de la même pièce d'horlogerie;
• la figure 4 est une vue semblable à celle de la figure 2B montrant le mobile denté, le dispositif d'indexation, la tige de mise à l'heure et le système de freinage d'une pièce d'horlogerie conforme à un deuxième mode de réalisation particulier; la tige de mise à l'heure étant montrée en première position tirée.

Other characteristics and advantages of the present invention will appear on reading the following description, given solely by way of non-limiting example, and made with reference to the appended drawings in which:

• them figure 1 , 2A and 3 are three plan views showing the indexing device, the time-setting stem and the braking system of a timepiece which conforms to a first particular embodiment, the three views respectively showing the stem time-setting in the neutral position, in the first pulled out position and in the second pulled out position;
• the figure 2B is a plan view similar to that of the figure 2A , and which still shows the toothed mobile of the same timepiece;
• the figure 4 is a view similar to that of the figure 2B showing the toothed wheel set, the indexing device, the time-setting stem and the braking system of a timepiece conforming to a second particular embodiment; the time-setting stem being shown in the first pulled out position.

DETAILED DESCRIPTION OF EMBODIMENTS

In the following description, the expressions “clockwise” and “counterclockwise” refer to the plan views of the appended figures.

The figure 1 , 2A and 3 illustrate the indexing device, the time-setting stem and the braking system of a timepiece which conforms to a first exemplary embodiment. The illustrated indexing device is formed of a jumper 11 pivotally mounted on a shaft 13 and elastic means consisting of a first leaf spring 15 arranged to bias the jumper 11 counterclockwise. In a manner known to those skilled in the art, the time-setting stem (referenced 17) can be actuated manually in translation between a neutral position ( Figure 1 ), a first drawn position ( Figure 2A ) and a second drawn position ( Figure 3 ), and it is also operable in rotation. The figures also show a second leaf spring 19 which is integral with jumper 11 and which, in accordance with what will be explained later, forms part of the braking system. It can be seen that the spring 19 has a part folded several times, so as to constitute a bearing surface 21 forming a projection and delimited on either side by two shoulders. The figures also show a control lever 23 which in the present example consists of a pull rod comprising a first and a second arm (referenced respectively 25 and 27) which extend on either side of a pivot axis 41 The pull tab 23 still carries an additional arm (reference 29). As shown more particularly by the figure 2A , the distal end of the arm 29 carries a pin 31 which is arranged to cooperate with the bearing surface 21. The additional arm 29 constitutes a switch arm which forms part of the aforementioned braking system. The pull tab 23 and the switch arm 29 are arranged to be controlled by the rod 17 so as to be in a first position ( Figure 1 ) when the rod is in neutral position, to be in a second position ( Figure 2A ) when the rod is in the first pulled position and to be in a third position ( Figure 3 ) when the rod is in the second pulled position. For this purpose, the first arm 25 of the pull tab 23 of this example carries a stud (not shown) which is engaged in a groove (not shown) of the rod 17.

Still referring to the same figures, it can be seen that the pull tab 23 and the switch arm 29 pivot progressively clockwise, when the time-setting stem 17 is first brought from its neutral position ( Figure 1 ) to the first drawn position ( Figure 2A ), and then brought from the first drawn position to the second ( Figure 3 ). The pin 31 being fixed to the end of the switch arm 29, it accompanies the pivoting of the pull rod by moving along a short arc of a circle (represented by a broken line and referenced 35 in the Figure 1 ) which is centered on the axis 41. In the illustrated embodiment, the short arc of a circle 35 can substantially be assimilated to a straight segment which extends parallel to the blade of the second spring 19. It will further be noted, that by following path 35, pin 31 intercepts the folded part of the spring. If we refer again to the Figure 1 , it can be seen that when the pull rod 23 is in the first position, the pin 31 is located away from the second spring 19 and its bearing surface 21, so that the switch arm 29 does not interact with the surface of support 21. Referring then to the figure 2A , it can be seen that when the pull tab is in the second position, the pin 31 is resting against the bearing surface 21, so that the pin causes the spring 19 to bend, pushing it back. Finally referring to the picture 3 , it can be seen that when the pull rod 23 is in the third position, the pin 31 is beyond the folded part of the spring 19 so that the switch arm 29 no longer interacts with the support surface 21 and does not practically no longer exerts any constraint on the second spring 19. Finally, returning to the figure 2A , it can also be seen that the force exerted by the pin 31 on the spring 19 is oriented so as to return the jumper 11 counterclockwise. It will therefore be understood that, when the pull tab 23 is in the second position, the force of return exerted by the second spring 19 on the jumper 11 is added to the return force exerted by the first leaf spring 15.

The figure 2B shows all the elements already described in relation to the figure 1 , 2A and 3 , and it also shows a toothed mobile consisting of a date disc 37 provided with internal toothing. It will further be noted that the Figure 2B illustrates the time-setting stem 17 in the first pulled out position, the configuration illustrated in the figure 2B being therefore identical to that of the figure 2A . The date disc 37 is arranged to be controlled from the movement (not shown) of the timepiece so as to be incremented once a day. In a manner known per se, the date disc 37 can for example be driven from the hour wheel (not shown) by means of a 24-hour wheel (not shown) provided with a drive finger arranged to actuate at each revolution one of the teeth 39 of the internal toothing of the date disc 37.

As already mentioned, the timepiece of the present example includes an indexing device consisting of the jumper 11 and by a first leaf spring 15 arranged to return the head of the jumper 11 against the internal toothing of the date disc 37. shown in the figures, the head of jumper 11 has two sides inclined in opposite directions. When a side presses against the tip of a tooth 39 of the date disc, the force exerted on the tooth by the jumper generates a torque which tends to bring the date disc back to a stable position in which the two sides press simultaneously against two consecutive teeth 39 (as shown in the figure 2B ). It will be understood that the function of the jumper is to ensure that the date disc advances exactly by the value of one tooth each time it is actuated by the drive finger (not shown).

In the example illustrated, the time-setting stem 17 makes it possible in particular to correct the time indicated by the hands (not shown) when it is in the first pulled out position. When, during the correction, the time indicated by the hands passes through midnight, the drive finger (not shown) carried by the 24-hour wheel pushes back one of the teeth 39 of the date disc 37 so as to drive the latter. As already mentioned, a drawback of such a correction system is that the user of the timepiece risks causing multiple jumps of the date disc 37 if he manipulates the time-setting stem 17 too energetically. Indeed, when setting the time, the drive finger, which is connected to the hands, moves much faster than during the normal operation of the timepiece. Under these conditions, when the finger strikes a tooth 39 of the date disc 37, it imparts a considerable impulse to the latter. The momentum of the date disc at this precise moment may even be such that, without the presence of the braking system, it would make several consecutive jumps before being immobilized by jumper 11.

In accordance with this embodiment, the time is corrected with the time-setting stem 17 in its first pulled-out position as illustrated in the Figures 2A and 2B . As already mentioned, in the configuration illustrated by these two figures, the pin 31 exerts on the spring 19 a force which is oriented so as to return the jumper 11 counterclockwise. This force is therefore added to the restoring force exerted by the first leaf spring 15. It will therefore be understood that the force with which the head of the jumper 11 presses against the internal toothing of the date disc 37 is greater when the time setting 17 is in the first pulled out position only when it is in one or the other of its two other axial positions. As already mentioned, the force exerted by the head of the jumper 11 on the teeth 39 of the date disc 37 is at the origin of a resistive torque which opposes the rotation of the disc. In addition, this resistant torque increases when the time-setting stem 17 is brought into the first pulled out position, due to the force exerted by the switch arm 29 on the second spring 19.

In accordance with what has just been explained, the second leaf spring 19, its bearing surface 21, the switch arm 29 and the pin 31 together form a braking system, and it will be understood that the latter is in a state active when the time-setting stem 17 is in the first pulled out position, and is on the other hand in an inactive state when the time-setting stem 17 is in the neutral position, as well as when it is in second drawn position. In the active state, the switch arm 29 deforms the spring 19 by exerting a force on the bearing surface 21, while in the inactive state, the switch arm 29 does not interact with the bearing surface 21.

The figure 4 is a partial view which shows the toothed wheel set, the indexing device, the time-setting stem and the braking system of a timepiece according to a second exemplary embodiment. This second embodiment has many characteristics in common with the first. This is the reason why the following description will be limited to describing the characteristics of the second mode which have not already been described in relation to the first. It should also be noted that the elements illustrated in the figure 4 , which are the same or equivalent to items shown in the figure 1 , 2A , 2B and 3 , are designated by the same reference numerals plus one hundred.

The main distinguishing characteristic of the second exemplary embodiment compared to the first is that the indexing device is constituted by a jumper spring (referenced 111). It can be seen that in the example illustrated, jumper spring 111 is formed of a leaf spring 119 which is integral with the frame of the timepiece by one of its ends and whose other end, which is free , constitutes the head 133 of the jumper. In a manner known per se, the head 133 of the jumper can be bent as illustrated, so as to comprise two sides which are inclined in opposite directions and which are arranged to cooperate with the teeth 139 of the date disc 137. Referring again to the figure 4 , it can be understood that, on the one hand, the leaf spring 119 elastically urges the head 133 of the jumper spring 111 against the teeth 139, and that on the other hand, the presence of the teeth prevents the leaf spring 119 from fully relaxing; the leaf spring therefore being maintained under stress. Jumper spring 111 is arranged so as to allow selective indexing of date disc 137 in a plurality of angular positions. When the two sides of the head 133 of the jumper spring press simultaneously against two consecutive teeth 139, as illustrated in the figure 4 , the date disc 137 is in one of its stable positions.

The jumper spring 111 of the present example is constituted by a leaf spring 119, and it will therefore be understood that the latter fulfills both the jumper function and that of elastic means arranged to urge the head 133 of the jumper in the direction of the jumper. toothing of the date disc 137. It can also be noted that, in the present example, the leaf spring 119 is not only part of the indexing device, but that it also constitutes the spring of the braking system of the part of watchmaking. In this regard, it can be seen that the leaf spring 119 has a part folded over several times and forming a projection. This projecting portion is delimited on either side by two shoulders, and it will be understood that it constitutes a support surface (referenced 121).

As was already the case in the previous example, the time-setting stem 117 is movable in translation between a neutral position, a first pulled out position and a second pulled out position, and it will be noted that the figure 4 shows the first position drawn. The timepiece of this example also includes a control lever 123 which, as in the previous example, consists of a pull tab which can occupy three predefined positions; the latter being respectively associated with the three axial positions of the time-setting stem 117. Finally, the timepiece comprises a commutator arm 129 which is integral with the pull-bar 123 by one of its ends and the other end of which carries a pin 131 which is arranged to cooperate with the support surface 121. Still referring to the figure 4 , it can be seen that the pin 131 bears against the bearing surface 121. Indeed, in accordance with the second exemplary embodiment, the braking system is in the active state when the time-setting stem is in the first drawn position.

When the timepiece is in the configuration illustrated in the figure 4 , and a user pushes the time-setting stem 117 back into the neutral position, the pull rod 123 pivots counterclockwise, so that the pin 131 carried by the switch arm 129 moves along a short trajectory in an arc. Conversely, when, starting from the configuration illustrated, a user brings the time-setting stem 117 to the second pulled out position, the pin 131 moves in the other direction, also following a short path in an arc of a circle. . The short trajectories in an arc of a circle associated with these two manipulations of the rod are represented by broken lines and referenced respectively 135a and 135b. It will be understood that the circular arc portions 135a and 135b are centered on the axis 141 around which the pull tab 123 pivots. It can also be seen that in the example illustrated, the short circular arc portions 135a, 135b can be assimilated to two straight line segments which extend substantially parallel to the support surface 121, as well as to the leaf spring 119. It will be understood that, when the pin moves on one of the paths 135a, 135b in arc of a circle, it can slide (or possibly roll) against the support surface 121, until it crosses one of the two shoulders which constitute its limits. Once past this shoulder, pin 131 is at a certain distance both from bearing surface 121 and from the rest of leaf spring 119. Switch arm 129 therefore no longer interacts with the bearing surface. In accordance with the second exemplary embodiment, the braking system is thus in the inactive state when the time-setting stem is in the neutral position, as when it is in the second pulled-out position.

We have seen that when the time-setting stem is in the first pulled out position, as illustrated in the figure 4 , the braking system is in the active state, with pin 131 resting against surface 121. In this configuration, pin 131 exerts pressure on bearing surface 121 tending to push back leaf spring 119 the toothing of the date disc 137. As already mentioned, the leaf spring 119 is secured to the frame by one of its ends, and its other end rests against the toothing of the date disc. It is therefore retained by its two ends. Under these conditions, the pressure exerted by the pin 131 does have the effect of moving the bearing surface 121 in the direction of the date disc 137, but the ends of the leaf spring 119 are on the other hand unable to follow the movement. The pressure exerted by the pin 131 on the bearing surface 121 therefore has the effect of further deforming the leaf spring, and this additional deformation itself has the effect of increasing the force exerted by the head 133 of the jumper spring 111 on the toothing of the date disc.

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 the present description without departing from the scope of the present invention defined by the appended claims. In particular, the invention is obviously not limited to embodiments in which the braking system is in the active state when the time-setting stem is in the first pulled out position, and is in the inactive state when the time-setting stem is in the neutral position and when it is in the second pulled-out position. According to other embodiments, the braking system could for example be in the inactive state only when the time-setting stem is in the neutral position, and be in the active state as well when the stem is in the second pulled out position than when it is in the first pulled out position. According to yet other embodiments, the braking system could be in the active state only when the time-setting stem is in second position drawn. Finally, the number of axial positions between which the time-setting stem is movable could naturally be different from three.

Claims (9)

1. Timepiece comprising a toothed wheel assembly (37; 137), an indexing device comprising a jumper (11; 111) and elastic means (15; 119) arranged to bias the head (133) of the jumper against the teeth (39; 139) of the toothed wheel assembly so as to index the wheel assembly, and a hand-setting stem (17; 117) which can move in translation between a neutral position and at least one first pulled position permitting the toothed wheel assembly (37; 137) to be actuated in rotation by causing the hand-setting stem to turn, characterised in that it comprises a braking system (19, 21, 29; 119, 121, 129) comprising a spring (19; 119) fixedly attached to the jumper (11; 111), and a bearing surface (21; 121) fixed to the spring, and also comprising a switching arm (29; 129) arranged to be controlled by the hand-setting stem (17; 117), the braking system being arranged to be in an inactive state, in which the switching arm (29; 129) does not interact with the bearing surface (21; 121) when the hand-setting stem (17; 117) is in the neutral position, and to be in an active state, in which the switching arm (29; 129) deforms the spring (19; 119) by exerting a force on the bearing surface (21; 121) when the hand-setting stem is in said first pulled position.
2. Timepiece as claimed in claim 1, characterised in that the hand-setting stem (17; 117) can move in translation between a neutral position, a first pulled position and a second pulled position, and in that the braking system (19, 21, 29; 119, 121, 129) is arranged to be in the active state, in which the switching arm (29; 129) deforms the spring (19; 119) by exerting a force on the bearing surface (21; 121) when the hand-setting stem is in the first pulled position, and to be in the inactive state, in which the switching arm does not interact with the bearing surface when the hand-setting stem is in the neutral position and when it is in the second pulled position.
3. Timepiece as claimed in claim 1, characterised in that it comprises a control lever (23; 123) arranged to be controlled by the hand-setting stem (17; 117) so as to be in a first position when the hand-setting stem is in the neutral position and to be in a second position when the hand-setting stem is in the first pulled position, and in that the switching arm (29; 129) of the braking system (19, 21, 29; 119, 121, 129) is fixedly attached to the control lever (23; 123).
4. Timepiece as claimed in claims 2 and 3, characterised in that the control lever (23; 123) is arranged to be in a third position when the hand-setting stem (17; 117) is in the second pulled position.
5. Timepiece as claimed in any one of the preceding claims, characterised in that the jumper (11) of the indexing device (11, 15) is pivoted about a spindle (13), and in that the elastic means (15) are arranged to bias the jumper in an angular manner.
6. Timepiece as claimed in claim 5, characterised in that the spring (19) of the braking system (19, 21, 29) is fixedly attached to the jumper (11) by one end, the spring (19) and the jumper (11) constituting the two arms of an indexing lever.
7. Timepiece as claimed in any one of claims 1 to 4, characterised in that the jumper (111) of the indexing device is a spring-jumper formed by a spring leaf (119), one end of which carries the head (133) of the jumper and the other end of which is fixed to the frame of the timepiece, the elastic means of the indexing device being formed by the spring leaf (119) of the spring-jumper.
8. Timepiece as claimed in claim 7, characterised in that the spring of the braking system (119, 121, 129) is formed by the spring leaf (119) of the spring-jumper (111), the bearing surface (121) being fixedly attached to the spring leaf (119).
9. Timepiece as claimed in claim 8, characterised in that the switching arm (129) carries a spur (131) arranged to move on a trajectory (135) substantially parallel to the bearing surface (121) when the hand-setting stem (117) passes from one axial position to another, and in that the spring leaf (119) has a protrusion, the peak of which forms the bearing surface (121).

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