Driving device for a clock movement comprising in particular a pivoting member

Abstract

The present invention relates to a drive device for equipping a clockwork mechanism and comprising a pivoting member (1) subjected to the action of a restoring force (2, 21) to determine at least one stable position of the pivoting member (1), said pivoting member (1) being intended to be driven in rotation against said restoring force (2) for the drive or actuating of a function of the clockwork mechanism. The pivoting member (1) comprises a control pawl (4) mounted for rotation on said pivoting member (1), and a return spring (42) maintaining said control pawl (4) in a rest position on the pivoting member (1). The control pawl (4) is arranged to cooperate with the clockwork mechanism for driving the pivoting member (1) against the action of its restoring force (2).The drive device further includes at least one locking stop (5) arranged to be in the stroke of the control pawl (4) when the pivoting member (1) in a stable position is driven into rotation during a shock against the action of its restoring force (2) while the control pawl (4) is in its rest position on the pivoting member (1).

Description

[0001] The present invention relates to a drive device for use in a clockwork movement, comprising in particular a pivoting member subjected to a restoring force and a shock-absorbing device. Specifically, this pivoting member is a rocker arm.

[0002] In watchmaking, a "rocker" is a pivoting mechanism with one or more arms that can assume at least one stable position. A control mechanism actuates the rocker, and a return spring determines the stable position(s). The movement of the rocker triggers various functions. Examples include the chronograph rocker, controlled by the column wheel, which starts or stops the chronograph wheel (this rocker is operated by the user via a pusher), and a date rocker, controlled by the movement, which triggers the date mechanism once a day.

[0003] In cases where the rocker is driven by movement, when the rocker is actuated, the movement must provide sufficient energy to overcome the return spring. To conserve energy during operation, it would be preferable for the return spring to be as weak as possible. On the other hand, it is also essential to ensure that the rocker does not move in the event of an impact, as this could trigger a rocker-actuated function unintentionally. The most obvious solution for implementing a shock-absorbing device is to apply a significant torque to the rocker, a torque that must be overcome or eliminated during its actuation. If the return spring also performs a shock-absorbing function, then a balance must be found between sufficient torque to ensure both the shock-absorbing and return functions and energy conservation during operation.

[0004] A known solution to avoid an excessively strong return spring, which would consume energy during the function transition, is to have a rocker arm with its center of mass as close as possible to its pivot point. However, this is not always advantageous or even possible: adding an unbalanced weight or counterweight takes up space, increases the weight of the rocker arm, and may require an additional assembly step. Achieving balance is even more difficult for large rocker arms, which inherently have a significant unbalance.

[0005] The object of the present invention is to provide a drive device for a timepiece comprising a pivoting member, in particular a rocker, and a shock-absorbing device to ensure that the pivoting member does not move sufficiently to perform its drive function during an impact. The drive device requires only minimal torque to move the pivoting member when driven by the movement. In the case of a rocker, one object of the present invention is to separate the torque required to return the rocker from the torque required to maintain the rocker's position in the event of an impact.

[0006] The present invention relates to a drive device intended to equip a watch movement according to claim 1, a watch movement according to claim 8 and a watch part according to claim 9.

[0007] The attached figures illustrate one embodiment of the invention.

[0008] THE figures 1a et 1b illustrate part of a calendar mechanism with a drive device according to an embodiment of the invention comprising, in particular, a rocker, the rocker being at rest, the figure 1a being a top view and the figure 1b being a view from below.

[0009] THE figures 2a et 2b illustrate the mechanism of the figure 1a at the beginning of the rocker mechanism's training for the date change, the figure 2a being a top view and the figure 2b being a view from below.

[0010] THE figures 3a et 3b illustrate the mechanism of the figure 1a at the end of the seesaw's training for the date change just before the seesaw falls and returns to its rest position, the figure 3a being a top view and the figure 3b being a view from below.

[0011] THE figures 4a et 4b illustrate the mechanism of the figure 1a during an impact on the mechanism, the figure 4a being a top view and the figure 4b being a view from below.

[0012] THE figures 5a et 5b illustrate the mechanism of the figure 1a When setting the time in a counter-clockwise direction, the figure 5a being a top view and the figure 5b being a view from below.

[0013] In the illustrated embodiment, the drive device is arranged to permit the actuation of the date wheel 100 of a date mechanism.

[0014] To achieve this, the device includes a pivoting member in the form of a date lever 1 (hereinafter simply the lever) pivotally mounted at A and subjected to the action of a return spring 2 which tends to push it into a rest position against a fixed stop (not shown). In the illustrated embodiment, the return spring 2 includes, in particular, a first elastic return arm 21 arranged to exert an elastic force on a first pin 11 fixed to the lever 1.

[0015] A 24-hour finger 102 is attached to an unillustrated wheel of the date mechanism and arranged to make one revolution per day. The 24-hour finger drives the rocker 1 once a day around midnight to rotate it against the action of its return spring 2.

[0016] A drive pawl 3 is pivoted on the rocker 1 and is subjected to the action of a return spring 30 fixed to the rocker 1. The drive pawl 3 is intended to cooperate with the date wheel 100 with triangular teeth to advance the latter by one step when the rocker 1 pivots driven by the 24-hour finger 102. The date wheel 100 carries a date indicator (not shown) which can take any suitable shape.

[0017] A jumper 101 positions the date wheel 100 and prevents it from pivoting in the opposite direction to the direction of drive by the rocker arm 1. To achieve this, the jumper 101 includes a first positioning arm 1011 arranged to cooperate with the teeth of the date wheel 100 for positioning and locking the latter. A return spring 1012 is arranged to constrain the jumper 101 against the teeth of the date wheel 100.

[0018] According to the present invention, the rocker 1 comprises a control ratchet 4 pivotally mounted on the rocker 1 and arranged to cooperate with the 24-hour finger 102. The control ratchet 4 includes, in particular, a control beak 41 arranged to cooperate with the 24-hour finger 102 and a ratchet spring 42 terminating in a fork 43 arranged to surround a second pin 12 fixed in the rocker 1. The fork 43 and the second pin 12 position the control ratchet 4 in its rest position ( figures 1a et 1b ).

[0019] According to the present invention, the drive device further comprises a shock-absorbing device arranged to maintain the rocker 1 in its rest position in the event of an impact. In the illustrated embodiment, the control pawl 4 includes a locking beak 44 arranged to cooperate with a locking stop 5 shaped to be in the travel of the locking beak 44 of the control pawl 4 when the rocker 1 pivots against the action of its return spring 2 in the event of an impact. The locking stop 5 may be fixed, but preferably it is a flexible stop. As illustrated in particular in the figures, the locking stop 5 is carried by a locking arm 22 of the return spring 2 of the rocker 1.If the locking stop is fixed, it is designed to prevent the rocker arm 1 from pivoting and driving the date wheel 100 in the event of an impact. If the locking stop is flexible, it is designed to exert additional torque in the event of an impact. This additional torque is chosen to prevent the rocker arm 1 from driving the date wheel during a maximum impact defined during the design of the device.

[0020] Figures 1a and 1b illustrate the rocker arm 1 in its rest position, bearing against a fixed stop (not shown). The rocker arm 1 is held in this rest position by its return spring 2. In this rest position, the control pawl 4 is also in its rest position, and the drive pawl 3 is not in the path of the teeth of the date wheel 100.

[0021] Once a day, around midnight, the 24-hour finger 102, driven by the clockwork mechanism, comes into contact with the control beak 41 of the control pawl 4. Initially, the 24-hour finger rotates the control pawl 4 without rotating the rocker 1. The control pawl 4 rotates on itself until the locking beak 44 comes to rest against a third pin 13 of the rocker 1 ( figure 2b During this free stroke of the control pawl 4, the locking beak 44 passes by the locking stop 5 without contact. Once the locking beak 44 is against the third pin 13, the control pawl 4, pushed by the 24-hour finger 102, drives the rocker 1, which pivots against the action of its return spring 2. The drive pawl 3 then engages the teeth of the date wheel 100 and advances it by one step.

[0022] THE figures 3a et 3b illustrate the maximum pivoting position of the rocker 1 before its fall and return to its rest position. The control pawl 4 is still against the third pin 13 of the rocker 1. The date wheel 100 has advanced one step, and the 24-hour hand 102, continuing its rotation, driven by the movement, will leave the control beak 41. In doing so, the rocker 1 pivots, pushed by the return arm 21 of its return spring 2, and returns to its rest position illustrated in the figures 1a et 1b Simultaneously, the control pawl 4 pivots on itself to also return to its rest position. In this position, the control pawl 4 can retract slightly upon contact with the locking stop 5 without being stopped by it when the rocker 1 falls into its rest position.

[0023] THE figures 4a et 4b illustrate an impact on the drive device which results in the rocker 1 pivoting from its rest position in the direction of actuation (counterclockwise in the figure 4a against the action of its return spring 21. The control pawl 4 pivots at A with the rocker 1 but does not pivot on the rocker 1 and remains in its rest position. In this rest position of the control pawl 4, the locking beak 44 comes to rest against the locking stop 5. The control pawl 4 then pivots on the rocker 1 until a locking face 45 comes to rest against the third pin 13 of the rocker 1. In this position of the control pawl 4 against the locking stop 5 and resting on the third pin 13 of the rocker 1, the rocker 1 is effectively locked before the control pawl 3 acts on the date wheel 100. The shock therefore did not cause any unintended actuation of the date wheel 100.

[0024] As mentioned above, the locking stop 5 can be fixed and arranged to prevent the rocker 1 from pivoting and driving the date wheel 100 in the event of an impact. In the illustrated embodiment, the locking stop 5 is flexible, carried by a locking arm 22 of the rocker 1's return spring 2. The locking stop 5 is arranged to exert additional torque on the rocker 1 in the event of an impact, in addition to the torque exerted by the elastic arm 21 of the return spring 2. This additional torque is chosen to prevent the rocker 1 from driving the date wheel 100 during a maximum impact defined during the design of the device.

[0025] Furthermore, with a flexible locking stop 5, it is possible to add an "all or nothing" function during correction. Indeed, if the date mechanism includes a corrector arranged to act directly on the rocker 1 when the user wants to correct the date, the locking stop 5 and the additional torque it exerts on the rocker 1 then create a resistance point that must be overcome (overcoming the torque exerted by the locking stop 5). The presence of such a resistance point prevents the user from making a partial correction.

[0026] THE figures 5a et 5bThese diagrams illustrate the setting of the time backward or counterclockwise in the movement comprising the date mechanism. In this case, the 24-hour hand 102 pivots in the opposite direction to the direction of operation and acts on the control beak 41 of the control pawl 4. This control pawl 4 pivots on the rocker 1 from its rest position against the action of its pawl spring 42. As it pivots, the control pawl 4 retracts to allow the 24-hour hand 102 to pass when it pivots counterclockwise for setting the time backward. Thus, the fork 43 of the control pawl 4, in conjunction with the second pin 12 of the rocker 1, allows the pawl spring 42 to perform its return function regardless of the direction of rotation of the control pawl 4.

[0027] The above embodiment has been described as an example only and modifications are possible without departing from the scope of the invention.

[0028] In particular, in the example above, the pivoting element – ​​the rocker 1 – is arranged to occupy only one stable position, its rest position. If the pivoting element is arranged to occupy several distinct stable positions, the shock-absorbing device may provide several locking stops, each associated with a stable position of the pivoting element and each designed to retain the control pawl in the event of an impact, thus locking the pivoting element and preventing it from leaving the stable position corresponding to the locking stop. Alternatively, a single locking stop may be arranged to act as a shock absorber for the rocker in all its stable positions.

[0029] In the above embodiment, the rocker 1 drives the date wheel 100 via a drive ratchet 3, but alternatively the rocker could have any suitable drive member such as a beak or a finger.

[0030] In general, the present invention relates to a drive device intended to equip a clockwork mechanism and comprising a pivoting member subjected to the action of a restoring force to determine at least one stable position of the pivoting member and intended to be driven in rotation against said restoring force for the drive or actuation of a function of the clockwork mechanism.

[0031] According to the invention, the pivoting member comprises a control pawl mounted for rotation on said pivoting member, and a return spring maintaining said control pawl in a rest position on the pivoting member. The control pawl is arranged to be driven by the clockwork mechanism which includes the drive device.

[0032] The drive device according to the invention further includes at least one locking stop arranged to be in the stroke of the control pawl when the pivoting member in a stable position is driven into rotation during a shock against the action of its restoring force while the control pawl is in its rest position on the pivoting member.

[0033] According to the invention, the pivoting member, its return force, the control pawl and its return spring, as well as the locking stop, are arranged such that: When the control pawl is actuated by the clockwork mechanism in a first direction while the pivoting member is in a stable position, said control pawl pivots on the pivoting member against the action of its return spring without driving the pivoting member and without contacting the locking stop until it reaches a first stop position on the pivoting member (no-load travel of the control pawl). Once in this first stop position, the control pawl, which continues to be actuated in the first direction by the clockwork mechanism, then drives the pivoting member in said first direction against the action of its return force. Said pivoting member can then drive a function of the clockwork mechanism.

[0034] When the pivoting member has reached its maximum travel in the first direction and actuated the function it is designed to drive, it returns to a stable position under the action of its return force. The control pawl, which is no longer actuated by the clockwork mechanism, also pivots in a second direction opposite to the first under the action of its return spring to return to its rest position on the pivoting member. When the control pawl pivots in the second direction to return to its rest position and / or when the pivoting member pivots under the action of its return spring to return to a stable position, the control pawl is not stopped by the locking stop.

[0035] When the pivoting member in a stable position is rotated against the action of its return spring during an impact and the control pawl is still in its rest position on the pivoting member (i.e. it has not been actuated by the mechanism), said control pawl comes to rest on the locking stop and rotates said control pawl in a second direction until it reaches a second stop position on the pivoting member in which the control pawl is in rest on the locking stop and prevents the pivoting member from pivoting against the action of its return force and from leaving its stable position, at least as long as the impact does not exceed a defined maximum impact.

[0036] Preferably, the pivoting element is a rocker that can take at least one stable position determined by the restoring force.

[0037] Preferably, the locking stop is flexible and is arranged to exert a torque on the control pawl sufficient to retain the control pawl and block the rotation of the pivoting member in a first direction from a stable position during a shock less than or equal to a defined maximum shock, thus preventing said pivoting member from leaving its stable position.

[0038] Preferably, the return spring is terminated by a fork cooperating with a pin of the pivoting member, the fork and the pin being arranged to allow the control pawl to retract when it is driven in a second direction by the clockwork mechanism and thus perform the return function regardless of the direction of rotation of the control pawl.

[0039] This results in a compact and highly effective drive system, specifically a rocker equipped with a shock absorber, that does not increase the energy required for the system to function under normal conditions. Furthermore, the option of a flexible locking stop allows the shock absorber to be adjusted precisely to the drive system's requirements.

Claims

1. A drive device intended to equip a clockwork mechanism and comprising a pivoting member (1) subjected to the action of a restoring force (2, 21) to determine at least one stable position of the pivoting member (1), said pivoting member (1) being intended to be driven in rotation against said restoring force (2) for the drive or actuating of a function of the clockwork mechanism, said pivoting member (1) comprising a control pawl (4) mounted movably in rotation on said pivoting member (1), a return spring (42) maintaining said control pawl (4) in a rest position on the pivoting member (1), the control pawl (4) being arranged to cooperate with the clockwork mechanism for driving the pivoting member (1) against the action of its restoring force (2), characterized by the fact thatthe drive device further includes at least one locking stop (5) arranged to be in the stroke of the control pawl (4) when the pivoting member (1) in a stable position is driven into rotation during a shock against the action of its restoring force (2) while the control pawl (4) is in its rest position on the pivoting member (1).

2. Drive device according to claim 1, characterized by the fact thatThe pivoting member (1), its return force (2), the control pawl (4) and its return spring (42) as well as the locking stop (5) are arranged so that: • when the control pawl (4) is actuated by the clockwork mechanism in a first direction when the pivoting member (1) is in a stable position, said control pawl (4) pivots on the pivoting member (1) against the action of its return spring (42) without driving the pivoting member (1) and without coming into contact with the locking stop (5) until it reaches a first stop position on the pivoting member (1); • once in this first stop position, the control pawl (4), which continues to be actuated in the first direction by the clockwork mechanism, then drives the pivoting member (1) in said first direction against the action of its return force (2);• when the pivoting member (1) has reached its maximum stroke in the first direction and actuated the function it is intended to drive, it falls back into a stable position under the action of its restoring force (2) and the control pawl (4) which is no longer actuated by the clockwork mechanism also pivots in a second direction opposite to the first under the action of its restoring spring (42) to find its rest position on the pivoting member (1), without being stopped by the locking stop (5);and so that • when the pivoting member (1) in a stable position is rotated against the action of its return spring (2) during an impact and the control pawl (4) is still in its rest position on the pivoting member (1), said control pawl (4) comes to rest on the locking stop (5) and rotates said control pawl (4) in a second direction until it reaches a second stop position on the pivoting member (1) in which the control pawl (4) is in rest on the locking stop (5) and prevents the pivoting member (1) from pivoting against the action of its return force (2) and from leaving its stable position, at least as long as the impact does not exceed a defined maximum impact.; 3. A drive device according to any one of the preceding claims characterized by the fact thatthe return spring (42) of the control pawl (4) is terminated by a fork (43) cooperating with a second pin (12) of the pivoting member (1), the fork (43) and the second pin (12) being arranged to allow the retraction of the control pawl (4) when it is driven in a second direction by the clockwork mechanism and so that the return spring (42) performs the return function regardless of the direction of rotation of the control pawl (4).

4. A drive device according to any one of the preceding claims characterized by the fact that the locking stop (5) is fixed.

5. Drive device according to any one of claims 1 to 3 characterized by the fact thatthe locking stop (5) is flexible and is arranged to exert a torque on the control pawl (4) sufficient to retain the control pawl (4) in its second stop position on the pivoting member (1) and to block the rotation of the pivoting member (1) in a first direction from a stable position during a shock less than or equal to a defined maximum shock, thus preventing said pivoting member from leaving its stable position.

6. Drive device according to claim 5, characterized by the fact that the pivoting member is a rocker (1) subjected to the action of a return spring (2) which includes a first elastic arm (21) which tends to maintain it in a stable position called the rest position, the return spring (2) including a second elastic arm (22) forming the elastic locking stop (5) cooperating with the control ratchet (4).

7. Device according to any one of the preceding claims, characterized by the fact thatIt is intended to drive a date mechanism, the pivoting part being a date rocker.

8. Clockwork movement comprising a drive device according to one of the preceding claims.

9. Timepieces comprising a movement according to claim 8.

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