Chronograph coupling

Abstract

The present invention relates to a chronograph coupling and comprises: - an input wheel mounted on an axis and configured to be driven by a drive system; - an output wheel positioned on an axis and configured to drive at least one chronograph counter; and - a coupling disc constrained to rotate with either the input wheel or the output wheel, positioned between the input wheel and the output wheel, and movable in the axial direction between a first position and a second position, wherein in the first position the coupling disc is held in contact with the other of the input wheel and the output wheel by an elastic member, thereby allowing the output wheel to rotate synchronously with the input wheel; and in the second position the coupling disc is separated from the other of the input wheel and the output wheel by an actuator, thereby allowing the input wheel to rotate relative to the output wheel. The coupling further comprises a braking wheel coaxial with the input wheel and in gentle frictional contact, wherein the braking wheel is configured to cooperate with a brake configured to be controlled synchronously with a zero-reset hammer, thereby causing the brake to block the braking wheel when the chronograph is zero-reset.

Description

Technical Field

[0001] The present invention relates to the field of watches. More specifically, it relates to a vertical coupling for a chronograph.

Background Art

[0002] So-called "vertical" couplings are commonly used to form a releasable kinematic connection between the drive train of a watch movement and a chronograph mechanism. They have the advantage of being compact within the plane of the movement. Also, since the drive is effected by friction rather than by meshing of teeth as in the case of a horizontal coupling or a sliding pinion coupling when the coupling is actuated, there is no risk that the seconds counter will jump when the coupling is actuated.

[0003] An example of a classical vertical coupling disclosed in Patent Document 1 includes an input wheel that is permanently kinematically connected to or incorporated in the drive train, and an output wheel that is coaxial with the input wheel and mounted on a common axis. Either the input wheel or the output wheel is rotatable relative to the common axis. A friction plate that is constrained to rotate with the output wheel is disposed on the axis between the input wheel and the output wheel and is held in contact with the input wheel by an elastic element. Thereby, the input wheel and the output wheel are constrained to rotate integrally by the friction between the input wheel and the coupling disk. The coupling disk can be lifted against the force of the elastic element by a pincer or a lever, and thus the contact between the coupling disk and the input wheel can be released. Thereby, the kinematic connection between the input wheel and the output wheel is released.

[0004] The pincer or lever is typically controlled by a column wheel, a shuttle, a cam, etc. for the purpose of stopping or starting the time count. When the user wants to zero-reset after stopping the counter, the coupling is released and one or more hammers act on the cam to return the counter to zero display.

[0005] While the counter is rotating, the coupling's output wheel may also be driven. Furthermore, due to structural tolerances, when the coupling re-engages, it may be necessary to compensate for (catch up) any play that occurred before the chronograph was driven again. This can cause a delay in the counter's start.

[0006] Therefore, an object of the present invention is to propose a coupling for chronographs that overcomes at least some of the above-mentioned problems. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] European Patent Application Publication No. 3869278 [Overview of the project] [Problems that the invention aims to solve]

[0008] More precisely, the present invention relates to a chronograph coupling as defined in claim 1. The coupling comprises the following:

[0009] - An input vehicle mounted on an axle and configured to be driven by a drive system, preferably by being kinematically branched and connected to the drive system.

[0010] - An output wheel positioned on the aforementioned axis and configured to drive at least one chronograph counter.

[0011] - A coupling disk that is constrained to rotate with either the input vehicle or the output vehicle, positioned between the input vehicle and the output vehicle, and movable in the axial direction between a first position and a second position, wherein in the first position, it is held in contact with the other of the input vehicle and the output vehicle by the action of an elastic element, thereby enabling the output vehicle to rotate synchronously with the input vehicle (i.e., under normal coupling operating conditions, friction constrains the input vehicle and the output vehicle to rotate substantially as a single unit), and in the second position, it is separated from the other of the input vehicle and the output vehicle by the action of an actuator such as a pincer or lever, thereby enabling the input vehicle to rotate relative to the output vehicle.

[0012] According to the present invention, the coupling further comprises a braking wheel coaxial with and in sliding contact with the input wheel, the braking wheel being configured to cooperate with a brake configured to be driven in sync with a zero-reset hammer, thereby causing the brake to block the braking wheel when the chronograph is zero-reset.

[0013] These means prevent the input vehicle from being driven in the reverse direction due to parasitic friction, particularly that caused by certain components that rotate freely on the axle, which is unavoidable in the coupling, through the cooperation between one fixed braking vehicle and the other input vehicle during zero reset. By controlling the friction between the input vehicle and the blocking vehicle, it is possible to overcome the effects of parasitic friction and prevent unwanted rotation that would cause play when the coupling is re-engaged, without relying on cooperation by friction fitting that would impair the function of the drive system and adjustment system.

[0014] Advantageously, the braking wheel has teeth with a module of up to 50%, preferably up to 25%, that of the input wheel. Thus, unwanted rotation when the braking wheel works with the brake can be minimized or completely eliminated. In embodiments that have been shown to function effectively, the input wheel's teeth had a module of 0.07 mm and the braking wheel's teeth had a module of 0.016 mm, a ratio of 23%.

[0015] Advantageously, the brake comprises a beak configured to cooperate with the teeth of the braking vehicle. However, brakes that operate by friction or the like are also possible.

[0016] Advantageously, the brake is pivotably mounted between a first position in which the brake wheel is separated from the brake wheel and not fixed, and a second position in which it works in cooperation with the brake wheel to fix it in place.

[0017] Advantageously, the brake is controlled to move between the first and second positions, preferably by a cam controlled by the hammer, or alternatively by any type of element (such as a lever) that performs this function, preferably via a rack supported by the latter (such as a lever). Alternatively, a molded cam, a rack, or any other suitable element may be used for the same purpose, but the solution employing a cam and rack is particularly simple and compact.

[0018] Advantageously, the output vehicle is constrained to rotate together with the coupling disk, while the input vehicle is mounted to rotate freely on the shaft.

[0019] Advantageously, the input wheel is mounted to rotate freely on an intermediate ring which is mounted to rotate freely on the shaft, and the braking wheel is constrained to rotate together with the intermediate ring.

[0020] Advantageously, the contact between the input wheel and the brake wheel is obtained by a plurality of contact elements carried by either the input wheel or the brake wheel, preferably the brake wheel. This facilitates the control of the friction between the brake wheel and the input wheel.

[0021] Advantageously, the contact elements are made of ruby. Alternatively, they can also be made from diamond, synthetic diamond, or any other material having a low coefficient of friction.

[0022] Advantageously, the coupling disk is constrained to rotate with the output wheel by the elastic element. Other alternative solutions are also known to those skilled in the art.

[0023] The coupling according to the invention can further be incorporated into a chronograph mechanism for a timepiece, which further comprises the following.

[0024] - At least one counter kinematically connected to the output wheel and provided with a reset cam.

[0025] - A zero reset hammer configured to cooperate with the reset cam.

[0026] The brake is configured to fix the block wheel during the zero reset of the chronograph.

Brief Description of the Drawings

[0027] [Figure 1] An isometric sectional view of the coupling according to the invention. [Figure 2] A side sectional view of the coupling of FIG. 1, showing the main interactions with standard symbols (in particular, "X" when constrained to rotate integrally and "I" when free to rotate). [Figure 3] An isometric view of a part of the coupling of FIG. 1, showing the cooperation with the brake.

Embodiments for Carrying Out the Invention

[0028] Further details of the present invention will become clearer by referring to the accompanying drawings and reading the following description.

[0029] The coupling 1 according to the present invention is of the vertical type, and its main components are arranged on the axis 3. This coupling 1 is adapted for use in conjunction with a chronograph mechanism. The term "chronograph mechanism" as used herein broadly encompasses any counting method that allows time units to be arbitrarily started and stopped, whether it be a classical chronograph, a countdown timer, or something similar.

[0030] An input wheel 5 is mounted on the shaft 3 so as to rotate freely in order to receive power from the movement and its drive source. The input wheel 5 directly or indirectly engages with a drive wheel 7, typically a seconds wheel, but this connection is optional. At the other end of the shaft 3 is an output wheel 9, which is constrained to rotate with the shaft 3 and directly or indirectly engages with at least one chronograph counter (not shown). The diameter ratio of the input wheel 5 to the output wheel 9 can be arbitrarily selected, but in the illustrated embodiment, the diameter of the output wheel 9 is larger than the diameter of the input wheel 5.

[0031] A coupling disc 11 is provided between the input vehicle 5 and the output vehicle 9 to provide a disengaged motion coupling between them. This coupling disc 11 is translationally movable along the shaft 3 and is held in a first position where it abuts against the side surface of the input vehicle 5 by the biasing force of the elastic element 13. As a result, sufficient friction is generated by the cooperation of these two elements, and they are constrained to rotate together in the event of any torque the coupling 1 receives while in operation.

[0032] The coupling disc 11 is slidable at least longitudinally on the shaft 3 and is constrained to rotate with the output vehicle 9 by a specific shape of the elastic element 13. The elastic element 13 comprises a central portion 13a having a non-circular opening mounted on a complementary non-circular cross-section 3a of the shaft 3, and ends 13b of a plurality of arms 13c that engage with respective notches 11a provided on the coupling disc. The arms 13c of the elastic element 13 are stressed (although the arms 13c are shown unstressed in the drawings, those skilled in the art will understand that the arms 13c elastically deform when the ends 13b engage with the notches 11a) so as to provide sufficient force to press the coupling disc 11 against the surface of the input vehicle 5 as described above.

[0033] Thus, when coupling 1 is engaged, input vehicle 5 is constrained to rotate together with output vehicle 9 by coupling disk 11 and elastic element 13.

[0034] The coupling disc 11 is further fitted and sized to cooperate with an actuator 12, such as a pincer or lever ( schematically shown as a pincer in Figure 2), in a known manner. This actuator 12 lifts the coupling disc 11 against the biasing force of the elastic element 13 and moves it to a second position, thereby disengaging the motion coupling between the input vehicle 5 and the output vehicle 9. As a result, when the coupling 1 is disengaged, the input vehicle 5 becomes rotatable relative to the output vehicle 9.

[0035] Other arrangements of the braking disc 11 and its elastic element 13 are also possible and can be applied as long as the above-described operation is achieved, within the scope known to those skilled in the art. Furthermore, it is also possible to reverse the coupling between the input wheel 5, the output wheel 9 and the shaft 3, that is, to restrain the input wheel 5 to rotate together with the shaft 3 and allow the output wheel 9 to rotate freely. Other modifications to the arrangement of the coupling disc 11 and the elastic element 13 are also within the technical scope of those skilled in the art.

[0036] When resetting the chronograph counter to zero, the output wheel 9 may rotate at a relatively large angle in one direction or the opposite direction. Due to friction between the various components located on the shaft 3, the input wheel 5 may be rotated in the opposite direction by the shaft 3. Subsequently, when the coupling 1 is re-engaged, the counter will not restart unless the resulting play is compensated for.

[0037] The solutions implemented by this invention are as follows:

[0038] The input vehicle 5 is mounted on the shaft 3 by a bearing 17 and an intermediate ring 15 that is typically constrained to rotate together with a ruby ​​ring. This component can be omitted if the intermediate ring 15 itself has a layer of hard material such as adamantine carbon, and this layer can replace the function.

[0039] The bearing 17 is mounted on the shaft 3 so as to be freely rotatable, and the input wheel 5 is mounted on the intermediate ring 15 so as to be freely rotatable. To hold the ring 15-bearing 17 assembly axially on the shaft 3, the shaft 3 is provided with a shoulder 3b against which the bearing 17 abuts, and a retaining ring 19 is fixed on the shaft 3 opposite the shoulder 3b. As a result, the bearing 17 is axially trapped between these two elements, the shoulder 3b and the retaining ring 19 (excluding functional clearance).

[0040] The brake wheel 21 is mounted on the intermediate ring 15 and constrained to rotate with the intermediate ring 15, and cooperates with the input wheel 5 by friction via a plurality of contact elements 25. The plurality of contact elements 25 are shown here as perforated stones made of ruby ​​or other hard material, but can alternatively be formed by studs, bosses or similar, or by simple side-to-side (flank-to-flank) contact with the input wheel 5. In another variation not shown, the intermediate ring 15 can be omitted, and its function can be replaced by a suitable shoulder surface provided on the brake wheel 21.

[0041] During zero reset, the brake 27 (see Figure 3) cooperates with the periphery of the braking wheel 21. In this embodiment, the brake 27 is a beak pivotably mounted on a frame element (not shown) that cooperates with the teeth of the periphery. The module of these teeth is smaller than the module of the input wheel 5. The module of the teeth of the braking wheel 21 is preferably in the range of 1 / 6 to 1 / 2, more preferably 1 / 5 to 1 / 3, of the module of the input wheel 5. Alternatively, the brake can also cooperate with the periphery of the braking wheel 21 by friction.

[0042] The brake 27 is controlled in accordance with the movement of the chronograph's zero-reset hammer. In the non-limiting embodiment shown, the hammer comprises a rack 29 cooperating with a pinion 30 constrained to rotate with a cam 33. The cam 33 cooperates with a follower 27a rigidly connected to the brake 27, causing the brake 27 to pivot and produce cooperation with the brake wheel 21 when the hammer cooperates with a reset cam (not shown). Alternatively, the hammer may comprise a molded cam (without teeth), a ratchet, or other suitable element instead of the rack 29. The cam 33 may also be replaced with a lever, finger, or other suitable element. However, other arrangements controlled directly or indirectly by a column wheel, shuttle, control cam, or similar element are equally possible.

[0043] To effectively control the friction between the braking wheel 21 and the input wheel 5, between the input wheel 5 and the intermediate ring 15, and between the bearing 17 and the shaft 3, the input wheel 5 is prevented from rotating in the reverse direction during zero reset, thereby avoiding the aforementioned play compensation.

[0044] Regarding friction, the cooperation between the braking vehicle 21 and the input vehicle 5 is not a "friction fit." While this method would also function, the resulting braking force risks braking the drive system and adversely affecting the operation of the oscillator. The cooperation between these components is a "sliding fit," that is, somewhere between a "friction fit" and "free rotation," and the magnitude of the friction can be considered to be sufficient to overcome the reverse force generated from the shaft 3 during zero reset, without being excessive.

[0045] These measures minimize the impact on the drivetrain and also minimize the additional resistance applied to the drivetrain when the brake 27 is engaged.

[0046] Other forms of brakes and their actuators are also possible.

[0047] Furthermore, even if the user blocks and holds the brake 27 against the braking vehicle 21, the drive system continues to function perfectly normally and does not affect the vibrator in any way (in contrast to a standard coupling system, where the drive system is blocked, the vibrator is disturbed, and may even stop after a certain period of time). Therefore, it should be noted that the user prepares for timing measurement by holding the brake and can start the measurement without delay the moment it is released.

[0048] Regarding usable materials, the entire range of modern watchmaking materials can be envisioned (various metals, silicon, silicon compounds and other nonmetals, synthetic diamonds, sapphires, structured glass, ceramics, glass ceramics, metallic glass, polymers, composite materials, materials suitable for additive manufacturing, etc.). Furthermore, flexible pivots can be applied where technically meaningful.

[0049] Although the present invention has been described with reference to specific embodiments, further modifications are possible without departing from the scope of the invention as defined in the appended claims.

Claims

1. A coupling for a chronograph (1), - An input vehicle (5) is mounted on the shaft (3) and configured to be driven by the drive system, - An output wheel (9) is positioned on the shaft (3) and configured to drive at least one chronograph counter, - A coupling disk (11) that is constrained to rotate with either the input vehicle (5) or the output vehicle (9), positioned between the input vehicle (5) and the output vehicle (9), and movable in the axial direction between a first position and a second position, wherein in the first position, it is held in contact with the other of the input vehicle (5) and the output vehicle (9) by the action of an elastic element (13), thereby enabling the output vehicle (9) to rotate synchronously with the input vehicle (5), and in the second position, it is separated from the other of the input vehicle (5) and the output vehicle (9) by the action of an actuator, thereby enabling the input vehicle (5) to rotate relative to the output vehicle (9). Equipped with, The coupling (1) further comprises a braking wheel (21) that is coaxial with and in sliding contact with the input wheel (5), and the braking wheel (21) is configured to cooperate with a brake (27) configured to be driven in sync with a zero-reset hammer, thereby the brake (27) blocking the braking wheel (21) when the chronograph is zero-reset, characterized in that the chronograph coupling (1).

2. The coupling (1) according to claim 1, wherein the braking gear (23) has teeth having up to 50%, preferably up to 25%, of the modules of the input gear (5).

3. The coupling (1) according to claim 2, wherein the brake (27) comprises a beak configured to cooperate with the teeth of the braking wheel (21).

4. The coupling (1) according to any one of claims 1 to 3, wherein the brake (27) is pivotably mounted between a first position separated from the braking vehicle (21) and a second position cooperating with the braking vehicle (21).

5. The coupling (1) according to claim 4, wherein the brake (27) is controlled by a cam (33) controlled by the hammer to move between the first position and the second position, preferably via a rack (29) supported by the hammer.

6. The coupling (1) according to any one of claims 1 to 5, wherein the output vehicle (9) is constrained to rotate together with the coupling disk (11), and the input vehicle (5) is mounted to rotate freely on the shaft (3).

7. The coupling (1) according to claim 6, wherein the input wheel (5) is mounted to rotate freely on an intermediate ring (15) which is mounted to rotate freely on the shaft (3), and the braking wheel (21) is constrained to rotate together with the intermediate ring (15).

8. The coupling (1) according to claim 6 or 7, wherein contact between the input vehicle (5) and the braking vehicle (21) is achieved by a plurality of contact elements (25) supported by either the input vehicle (5) or the braking vehicle (21), preferably the braking vehicle (21).

9. The coupling (1) according to claim 8, wherein the contact element (25) is made of ruby.

10. The coupling (1) according to any one of claims 6 to 9, wherein the coupling disk (11) is constrained by the elastic element (13) to rotate together with the output vehicle (9).

11. - The coupling (1) according to any one of claims 1 to 10, - At least one counter kinematically connected to the output vehicle (9) and equipped with a reset cam, - A zero-reset hammer configured to cooperate with the reset cam and Equipped with, The brake (27) is configured to block the brake wheel when the chronograph is zero-reset, in a chronograph mechanism for a watch.

12. A watch movement comprising the chronograph mechanism described in claim 11.

13. A clock comprising the clock movement described in claim 12.

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