Timepiece or animation mechanism

Abstract

The clockwork or animation mechanism according to the invention comprises a mainspring (11), a gear train (27), and a control member (15) meshing with an input member (17) of the gear train (27). The mainspring (11) includes a portion (13) that can be moved by a user from a first extreme position to a second extreme position to wind the mainspring (11) and that, as soon as it is released, returns to the first extreme position under the effect of the mainspring's unwinding. This return of said portion (13) to the first extreme position moves the control member (15) from a third extreme position to a fourth extreme position. This movement of the control member (15) from the third to the fourth extreme position drives the input member (17) and thus the gear train (27).The control member (15) is arranged to move from the fourth to the third extreme position when said portion (13) of the drive spring (11) is moved by the user from the first to the second extreme position. The control member (15) forms a non-circular gear with the input member (17).

Description

[0001] The present invention relates to a clockwork or animation mechanism, more particularly a clockwork or animation mechanism whose mainspring comprises a portion, typically an end portion, which can be moved by a user in one direction to wind the mainspring and which, as soon as it is released, is moved in the opposite direction by the relaxation of the mainspring, this movement in the opposite direction driving a cog of the mechanism. The mechanism may be, for example, an automaton mechanism or a minute repeater mechanism.

[0002] In such a mechanism, the force delivered by the mainspring during its expansion is not constant, and even varies rapidly from a maximum force to a minimum force. This variation in force is transmitted in the gear train. It must therefore be anticipated during the design of the mechanism by suitable sizing of the different components which can be difficult to find, especially when the mainspring is in the form of a simple blade, whose force is less stable than that of a classic spiral spring.

[0003] The present invention aims to propose a solution which allows the cog of a clockwork or animation mechanism to receive a constant or more constant driving force.

[0004] To this end, the present invention relates to a timepiece or animation mechanism comprising a mainspring, a train and a control member meshing with an input member of the train, the mainspring comprising a portion which can be moved by a user from a first extreme position to a second extreme position to wind the mainspring and which, as soon as it is released, returns to the first extreme position under the effect of the relaxation of the mainspring, this return of said portion to the first extreme position moving the control member from a third extreme position to a fourth extreme position, this movement of the control member from the third to the fourth extreme position driving the input member and therefore the train, the control member being arranged to move from the fourth to the third extreme position when said portion of the mainspring is moved by the user from the first to the second extreme position,the control member forming with the input member a non-circular gear.,

[0005] Thanks to the non-circular gearing, the variation in the force delivered by the mainspring can be at least partially compensated so that the gear train ultimately receives a substantially constant force. It is also possible to use the non-circular gearing to smooth out one or more force peaks generated by the mechanism.

[0006] Typically, the gear ratio between the control member and the input member, when the control member moves from the third to the fourth extreme position, varies in the same direction as the force of the mainspring. Advantageously, this gear ratio, from the third extreme position to the fourth extreme position of the control member, varies by at least 15%, preferably by at least 20%, preferably by at least 25%.

[0007] Said portion of the mainspring is for example an end portion.

[0008] To optimize space, the mainspring is preferably an unwound blade, curved or straight.

[0009] Preferably, the mainspring and the control member are in contact. Such an arrangement simplifies the construction of the mechanism.

[0010] According to another advantageous characteristic, said portion of the motor spring can be moved by the user from the first extreme position to the second extreme position by means of the control member.

[0011] In a typical embodiment, the input member is part of a one-way clutch mobile of the train which decouples the input member from the rest of the train when the control member moves from the fourth extreme position to the third extreme position.

[0012] The control organ is, for example, a rake.

[0013] The input member is for example a non-circular pinion or wheel.

[0014] According to particular applications of the invention, the mechanism is an automaton mechanism or a striking mechanism.

[0015] The present invention further provides a timepiece, such as a watch or a clock, comprising a mechanism as defined above.

[0016] Other characteristics and advantages of the present invention will appear on reading the following detailed description made with reference to the appended drawings in which: there figure 1 is a perspective view of a part of a clockwork or animation mechanism according to a particular embodiment of the invention; figures 2 et 3 are plan views showing the interactions between a mainspring, a control rack and a one-way clutch mobile of the mechanism illustrated in figure 1 .

[0017] The mechanism 10 partially illustrated in the figure 1 is an animation mechanism, that is to say a mechanism for purely decorative and entertaining purposes, and preferably an automaton mechanism. The mechanism 10 could nevertheless be a clockwork mechanism, for example a chime-type complication such as a minute repeater.

[0018] The mechanism 10 comprises a mainspring 11 consisting of a simple curved, unwound blade, working in flexion. Compared to the spiral springs of the barrels, such a mainspring makes it possible to simplify and optimize the size. On the other hand, the force it produces depending on its degree of winding varies more than that of a spiral spring.

[0019] The motor spring 11 is fixed by its base 12 to the frame of the mechanism 10 and ends with a free end portion 13 forming a step. The free end portion 13 bears against the handle 14 of a control rack 15 which is pivoted around an axis 15a and whose toothed sector 16 meshes with a pinion 17 with sectoral teeth.

[0020] The pinion 17 is part of a one-way clutch mobile 18 further comprising a wheel 19 coaxial with the pinion 17 and a transmission member 20 integral in rotation with the pinion 17 (cf. figures 2 et 3 ). A ring 21 projecting from the plate of the wheel 19 has on its inner surface notches 22 regularly distributed around the axis 18a of the mobile 18. The transmission member 20 comprises a base 23 mounted on the axis 18a of the mobile 18 and from which extends a bent arm composed of a rigid radial portion 24 and an elastic circumferential portion 25 connected to the base 23 by the rigid radial portion 24. The shape of the free end 26 of the elastic circumferential portion 25 is adapted to that of the notches 22. The free end 26 can thus engage in the notches 22 (cf. figure 2 ) to allow the transmission member 20 to push the wheel 19 in the manner of a ratchet when the pinion 17 and the transmission member 20 rotate in the direction corresponding to the clockwise direction of the figures. When the pinion 17 and the transmission member 20 rotate in the other direction, the free end 26 comes out of the notch 22 where it is located by bending the elastic circumferential portion 25 and slides on the inner surface of the ring 21 without driving the wheel 19. The transmission member 20 could comprise a second arm symmetrical to the arm 24, 25 with respect to the axis 18a of the one-way clutch mobile 18 and also cooperating with the notches 22.

[0021] The pinion 17 is the input member of a gear train 27 formed of the pinion 17, the wheel 19, a wheel 28 meshing with the wheel 19 and other wheels not shown, this gear train 27 being arranged to actuate decorative elements of the animation. A second gear train 29 may be provided, to connect the wheel 19 of the unidirectional clutch wheel 18 to a regulating member 30 making it possible to regulate the speed of the gear train 27.

[0022] The control rake 15 comprises, in addition to the handle 14 and the toothed sector 16, a heel 31 on which a manual actuating member (not shown) of the pusher type or other can act directly or indirectly. When the user actuates the manual actuating member (see the arrow on the figure 3 ), the latter pivots the control rack 15 in the direction corresponding to the clockwise direction in the figures, which rotates the pinion 17 and the transmission member 20 in the counterclockwise direction without driving the wheel 19 and therefore without driving the rest of the gear train 27, and which moves the end portion 13 of the mainspring 11 in the direction indicated by the arrow, thus arming the mainspring 11. More concretely, the user can, by means of the manual actuating member, move the control rack 15 from an extreme position illustrated in figure 2 to another extreme position illustrated in the figure 3 , these two extreme positions being defined by stops (not shown). Simultaneously, the end portion 13 of the motor spring 11 is moved between two extreme positions, the first of these positions ( figure 2 ) corresponding to a disarmed state of the mainspring 11, the second of these positions ( figure 3 ) corresponding to an armed state of the mainspring 11.

[0023] When the control rake 15 and the end portion 13 of the motor spring 11 are in their extreme position of the figure 3 , the free end 26 of the arm 24, 25 has not only come out of the notch 22 where it was located but has also moved beyond the adjacent notch in the counterclockwise direction. As soon as the user releases the manual actuating member, the motor spring 11 relaxes by pushing the control rack 15 by its end portion 13, which control rack 15 pivots the pinion 17 and the transmission member 20 in the clockwise direction. During this movement, the free end 26 of the arm 24, 25 engages in said adjacent notch and pushes the wheel 19 in the clockwise direction, thus driving the decorative elements of the animation by the gear train 27, the animation stopping when the control rack 15 reaches its extreme position illustrated in figure 2 .

[0024] According to the invention, the control rack 15 and the pinion 17 together form a non-circular gear. In other words, the toothing of the control rack 15 is not on a circle centered on the axis of rotation 15a of the control rack 15 and the toothing of the pinion 17 is not on a circle centered on the axis of rotation 18a of the pinion 17. This leads to a variable gear ratio between the two extreme relative positions of the control rack 15 and the pinion 17. Typically, the gear ratio between the control rack 15 and the pinion 17 varies in the same direction as the force of the mainspring 11, i.e. it decreases as the mainspring 11 relaxes. In this way, the gear 27 is driven with a constant torque, at least more constant than if the gear formed by the control rack 15 and the pinion 17 were circular.

[0025] In typical embodiments, the gear ratio between the drive rake 15 and the pinion 17, from the relative extreme position illustrated in figure 3 to that illustrated in the figure 2 , varies (decreases) by at least 15%, preferably by at least 20%, preferably by at least 25%. Naturally, this variation in the gear ratio can be adapted to the variation in force of the mainspring 11, whether it is lower or higher.

[0026] In other embodiments, the gear ratio between the control rack 15 and the pinion 17 varies in a non-monotonic manner, for example to take into account, as an alternative or in addition to the variation in force of the mainspring 11, a torque peak that the animation requires at a certain moment.

[0027] Those skilled in the art will understand that modifications could be made to the invention described above without departing from the scope of the claimed invention. In particular, the manual actuating member could act on the end portion 13 of the mainspring 11 other than via the control rack 15, for example by cooperating with an extension that this end portion 13 would comprise, and a return spring could keep the handle 14 of the control rack 15 in contact with this end portion 13. Furthermore, the mainspring 11 could have a shape other than that shown and be armed by a force applied at a point distant from its ends. The invention could also be applied to a mechanism not comprising a one-way clutch and in which, like the control rack 15, the gear train 27 would move back and forth.

Claims

1. Clockwork or animation mechanism comprising a mainspring (11), a train (27) and a control member (15) meshing with an input member (17) of the train (27), the mainspring (11) comprising a portion (13) which can be moved by a user from a first extreme position to a second extreme position to wind the mainspring (11) and which, as soon as it is released, returns to the first extreme position under the effect of the relaxation of the mainspring (11), this return of said portion (13) to the first extreme position moving the control member (15) from a third extreme position to a fourth extreme position, this movement of the control member (15) from the third to the fourth extreme position driving the input member (17) and therefore the train (27),the control member (15) being arranged to move from the fourth to the third extreme position when said portion (13) of the motor spring (11) is moved by the user from the first to the second extreme position, the control member (15) forming with the input member (17) a non-circular gear., 2. A mechanism according to claim 1, wherein the gear ratio between the control member (15) and the input member (17), when the control member (15) moves from the third to the fourth extreme position, varies in the same direction as the force of the mainspring (11).

3. Mechanism according to claim 2, wherein the gear ratio between the control member (15) and the input member (17), from the third extreme position to the fourth extreme position of the control member (15), varies by at least 15%, preferably by at least 20%, preferably by at least 25%.

4. Mechanism according to one of claims 1 to 3, in which said portion (13) of the motor spring (11) is an end portion.

5. Mechanism according to one of claims 1 to 4, in which the motor spring (11) is an unwound blade.

6. Mechanism according to one of claims 1 to 5, in which the motor spring (11) and the control member (15) are in contact.

7. Mechanism according to one of claims 1 to 6, in which said portion (13) of the motor spring (11) is movable by the user from the first extreme position to the second extreme position by means of the control member (15).

8. Mechanism according to one of claims 1 to 7, in which the input member (17) is part of a one-way clutch mobile (18) of the gear train (27) which decouples the input member (17) from the rest of the gear train (27) when the control member (15) moves from the fourth extreme position to the third extreme position.

9. Mechanism according to one of claims 1 to 8, in which the control member (15) is a rake.

10. Mechanism according to one of claims 1 to 9, in which the input member (17) is a non-circular pinion or wheel.

11. Mechanism according to one of claims 1 to 10, consisting of an automaton mechanism or a striking mechanism.

12. Timepiece comprising a mechanism according to one of claims 1 to 11.

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