Transmission mechanism for a timepiece movement

Abstract

The invention relates to a clockwork transmission mechanism (1) comprising a transmission unit including a drive plate (40), intended to pivot about a first axis of rotation in response to the movements of a driving unit, and a connecting member (2) having a flexible portion (36) and carrying a unidirectional transmission member (18, 20) arranged to cooperate with an output unit (4) intended to drive a driven unit when the driving unit moves in a first direction of movement, the connecting member (2) comprising a base (6) integral with the drive plate (40) and arranged to exhibit a rotational movement about the first fixed axis of rotation, in response to the movements of the driving unit, and a first arm (8, 10) extending from the base (6) and carrying the unidirectional transmission member (18, 20) at its distal end, the flexible portion (36) being arranged on the arm (8, 10).

Description

Technical field

[0001] The present invention relates to a transmission mechanism, for a watch movement, intended to transmit the movements of a driving wheel set to a driven wheel set of the watch movement, the mechanism comprising a transmission wheel set comprising a drive plate, intended to be kinematically connected to the driving wheel set and to pivot along a first fixed axis of rotation in response to the movements of the driving wheel set, as well as a connecting member having a flexible portion and carrying a unidirectional transmission member arranged to cooperate with a drive surface of an output wheel set intended to be connected to the driven wheel set, and to drive it when the driving wheel set moves in a first direction of movement.

[0002] According to a preferred embodiment, the invention relates to an automatic winding mechanism comprising a transmission mechanism of this type for connecting a winding mass and a mechanical energy storage device.

[0003] The present invention also relates to a watch movement provided with such a transmission mechanism as well as a timepiece comprising such a watch movement. State of the art

[0004] Clock mechanisms of this type are already known in the prior art, particularly in relation to automatic winding mechanisms.

[0005] Thus, for example, patent EP 3203326 B1 illustrates and describes a transmission mechanism meeting the above characteristics. More specifically, this transmission mechanism is intended to convert the bidirectional rotational movement of a winding mass into a unidirectional movement making it possible to ensure the winding of a barrel spring. To this end, the mechanism comprises a first rotary wheel set intended to be driven by the movements of the winding mass, in one direction or the other. This first wheel set carries a transmission disc eccentric relative to the axis of rotation of the first wheel set and arranged to drive a transmission member following a circular translational movement. The transmission member in turn cooperates with a clutch member arranged to allow unidirectional rotational drive of an output wheel set intended to be connected to one end of a barrel spring, to ensure the loading of the latter.For this purpose, the transmission member carries two drive surfaces capable of having a buttress connection with the clutch member, each of which is associated with a given direction of rotation. For each direction of rotation of the winding mass, the drive surfaces are alternately brought closer to and further away from the clutch member, in a reciprocating movement, due to the circular translational movement of the transmission member. Thus, the drive surfaces cooperate alternately with the clutch member to drive it in rotation in a single direction of rotation.

[0006] Such a construction requires great precision in the production and positioning of the various components involved, to ensure that the trajectory of the drive surfaces effectively achieves the intended buttress connection with the clutch member.

[0007] Patent FR 1022726 concerns another automatic winding mechanism. Disclosure of the invention

[0008] A main object of the present invention is to propose a clock transmission mechanism having a more compact and substantially simplified alternative construction with reference to the conversion mechanism described in patent EP 3203326 B1.

[0009] To this end, the present invention relates more particularly to a transmission mechanism of the type indicated above, in which the connecting member comprises a base secured to the drive board and arranged to present a rotational movement along the first fixed axis of rotation, in response to the movements of the driving mobile, and in which the connecting member comprises a first arm extending from the base and carrying the unidirectional transmission member at its distal end, the flexible portion being arranged on the arm so as to allow deformation of the latter when the connecting member is driven in rotation.

[0010] Thanks to these characteristics, the arm of the connecting member can be shaped and dimensioned, including for its flexible portion, so as to ensure the correct implementation of the unidirectional drive of the output mobile by the unidirectional transmission member, while driving the connecting member following a simple rotational movement.

[0011] Preferably, the arm carries at least one additional flexible portion.

[0012] This feature provides more flexibility to the mechanism manufacturer regarding the choice of arm shape.

[0013] Generally, when the output mobile is intended to be pivoted along a second fixed axis of rotation, it may further be provided that the distal end of the arm is secured to a radial guide arm arranged to pivot along the second fixed axis of rotation while being free to rotate with reference to the output mobile.

[0014] In this case, it can further be provided that the unidirectional transmission member is arranged on the distal end so as to be able to pivot with reference to the latter, along a third mobile axis of rotation, and carries a contact surface arranged to have an arched relationship with the drive surface of the output mobile, in such a way: that the contact surface drives the drive surface in a first direction of relative rotation between the radial guide arm and the output wheel, and that the contact surface moves without driving the drive surface in the opposite direction of relative rotation between the radial guide arm and the output wheel.

[0015] It is then advantageous to provide that the arm of the connecting member or the radial guide arm carries an elastic return member arranged to act on the unidirectional transmission member and tend to position it in a predefined rest position.

[0016] Generally, it can be provided that the connecting member carries a second arm, having structural characteristics similar to those of the first arm and carrying an additional unidirectional transmission member, arranged to drive the drive surface of the output mobile when the driving mobile moves in a second direction of movement, opposite to the first direction of movement.

[0017] Such a construction is less restrictive from the point of view of the production of the components and their arrangement than in the mechanism of the prior art cited above, given that an arm carrying at least one flexible portion is associated with each of the unidirectional transmission members.

[0018] In this case, it is advantageous to provide that the first and second arms extend in respective general directions inclined relative to each other at an angle of between 70 and 110 degrees.

[0019] According to a preferred embodiment, the present invention relates to an automatic winding mechanism comprising a transmission mechanism meeting in whole or in part the characteristics which have just been explained, and comprising a winding mass intended to be mounted on a frame element of the watch movement so as to be able to pivot with reference to the latter and having a kinematic connection with the drive board.

[0020] In this case, it is preferable to provide that the winding mass is arranged to exhibit oscillating movements of low amplitude, preferably less than 20 degrees, more preferably less than 10 degrees.

[0021] The present invention generally relates to a watch movement comprising a transmission mechanism meeting the characteristics set out above, whether or not it is integrated into an automatic winding mechanism, as well as a timepiece comprising such a watch movement. Brief description of the drawings

[0022] Other characteristics and advantages of the present invention will appear more clearly on reading the detailed description of a preferred embodiment which follows, made with reference to the appended drawings given by way of non-limiting example and in which: there figure 1 represents a schematic diagram of a part of a transmission mechanism according to the present invention, making it possible to explain the operating principle, the figure 2represents a simplified perspective view of a part of a transmission mechanism according to a preferred embodiment of the present invention, seen from a first face, and the Figures 3a and 3b represent the same front view of the transmission mechanism of the figure 2 , seen from its second side and in two different respective operating phases. Method(s) of carrying out the invention

[0023] The following detailed description seeks to describe a clockwork transmission mechanism according to a preferred embodiment of the present invention by way of non-limiting illustrative example. More specifically, according to the embodiment illustrated and described, the transmission mechanism is intended to be integrated into an automatic winding mechanism of a timepiece but, of course, those skilled in the art will be able to implement the transmission mechanism according to the invention in relation to other types of clockwork mechanisms without departing from the scope of the present invention as defined in the set of claims.

[0024] There figure 1 represents a schematic diagram of part of a transmission mechanism 1 according to the invention making it possible to explain the general operating principle.

[0025] Generally speaking, the transmission mechanism 1 according to the invention is intended to convert bidirectional rotational movements of a driving mobile (not shown) into unidirectional rotational movements of a driven mobile. To this end, the transmission mechanism 1 comprises in particular a connecting member 2 intended to be driven in bidirectional rotation from the movements of the driving mobile and to drive in turn an output mobile 4 following a unidirectional rotational movement.

[0026] When the transmission mechanism 1 according to the invention is integrated into an automatic winding mechanism, it can advantageously be arranged to convert the bidirectional rotational movements of a winding mass (not shown) into unidirectional rotational movements, before the latter are transmitted to a mechanical energy storage member to charge it with mechanical energy, typically a barrel spring (not shown).

[0027] Returning to the schematic diagram of the figure 1 , it appears that the connecting member 2 comprises a base 6 intended to be mounted for rotation on a frame element of a watch movement.

[0028] The base 6 carries two arms 8, 10 extending in general directions inclined relative to each other, towards a region close to the periphery of the output wheel set 4, intended to be kinematically connected to the mechanical energy storage member in the case of an automatic winding mechanism.

[0029] Each of the arms 8, 10 comprises, at its distal end, a support 14, 16 on which a unidirectional transmission member 18, 20, having the general shape of a circular wheel, is rotatably mounted, along an axis of rotation 22, 24. Finally, in the present exemplary embodiment, a radial guide arm 26, 28 is provided to connect each support 14, 16 to the axis of rotation 30 of the output wheel set 4 and thus maintain the corresponding axis of rotation 22, 24 at a constant distance from the axis of rotation 30.

[0030] It can be seen that each of the rotation axes 22, 24 is slightly offset relative to a radius passing through the rotation axis 30 of the output wheel set 4 and the point of contact of the latter with the corresponding unidirectional transmission member. In addition, each rotation axis 22, 24 is preferably slightly eccentric relative to the circular periphery of the corresponding unidirectional transmission member, the latter defining a contact surface with the output wheel set 4.

[0031] Thus, it appears that, starting from the configuration illustrated on the figure 1, if the unidirectional transmission member 18 pivots in the clockwise direction of rotation, it will have an increasingly large radius on the radius passing through the axis of rotation 30 of the output wheel set 4 and the point of contact of the latter with the unidirectional transmission member 18. Such a situation occurs when the connecting member 2 rotates clockwise in the view of the figure 1 .

[0032] The distance between the axis of rotation 22 of the unidirectional transmission member 18 and the periphery of the output wheel 4 being kept constant, the pivoting of the unidirectional transmission member 18 will give rise to a connection by bracing with the output wheel 4 after a certain time, that is to say when its radius located between its axis of rotation 22 and its point of contact with the periphery of the output wheel 4 becomes sufficiently large to prevent free pivoting of the unidirectional transmission member 18. From this moment, any subsequent rotation of the connecting member 2 in the same direction of rotation (clockwise in the view of the figure 1 ) also causes the output wheel 4 to rotate in the same direction of rotation, due to the significant friction occurring between the latter and the unidirectional transmission member 18, which can then no longer pivot on its axis of rotation 22.

[0033] Conversely, when the connecting member 2 rotates counterclockwise in the view of the figure 1 , the unidirectional transmission member 18 also rotates counterclockwise. By following such a movement, its radius located between its axis of rotation 22 and its point of contact with the periphery of the output mobile 4 tends to decrease. The unidirectional transmission member 18 can therefore rotate freely (again, if it was in a bracing situation) relative to the output mobile 4. Thus, when the connecting member 2 pivots in the counterclockwise direction of rotation, the unidirectional transmission member 18 does not drive the output mobile 4 in rotation.

[0034] It emerges from the figure 1that the other unidirectional transmission member 20 is mounted on its support 16 in a similar manner to that of the unidirectional transmission member 18. However, the arms 8 and 10 extend on either side of the straight line passing through the centers of the connecting member 2 and the output mobile 4. As a result, for a given direction of rotation of the connecting member 2, the two unidirectional transmission members 18 and 20 cooperate with the periphery of the output mobile 4 in such a way that they pivot in respective opposite directions of rotation. Consequently, each of the unidirectional transmission members 18, 20 is associated with a given direction of rotation of the connecting member 2, in which it has a bracing connection with the output mobile 4 to drive the latter in rotation.

[0035] In the configuration illustrated on the figure 1, a rotation of the connecting member 2 in the clockwise direction of rotation therefore causes a rotation of the unidirectional transmission member 18 in the same direction, which tends to place it in a situation of buttressing with the output mobile 4 to drive the latter in the clockwise direction of rotation. At the same time, the unidirectional transmission member 20 rotates freely in the counterclockwise direction without exerting any particular action on the periphery of the output mobile 4.

[0036] Conversely, a rotation of the connecting member 2 in the counterclockwise direction of rotation causes a free rotation in the same direction of the unidirectional transmission member 18, with reference to the output wheel set 4. At the same time, the unidirectional transmission member 20 rotates clockwise, which tends to place it in a situation of buttressing with the output wheel set 4 to drive the latter in the clockwise direction of rotation.

[0037] Thus, whatever the direction of rotation of the connecting member 2, the unidirectional transmission members 18, 20 alternately ensure the driving of the output mobile 4 in a single direction.

[0038] It will be noted that a return spring 32 is preferably associated with each unidirectional transmission member 18, 20, cooperating with a pin 34 integral with the latter, to prevent its orientation from straying too far from the orientation in which the interaction by bracing with the output wheel set 4 occurs, and thus ensure greater responsiveness to the transmission mechanism according to the invention, in particular during changes in the direction of drive of the connecting member 2.

[0039] Of course, the operating principle just described can be implemented with a single arm carrying a single unidirectional transmission member. In this case, when the transmission mechanism is integrated into an automatic winding mechanism for example, only one direction of rotation of the winding mass will contribute to the charge of the mechanical energy storage member.

[0040] According to a preferred embodiment of the invention, but in a non-limiting manner, each of the arms 8, 10 has, between its proximal end secured to the base 6 of the connecting member 2 and its distal end comprising the corresponding support 14, 16, two flexible portions 36 intended to allow the arm 8, 10 to deform when the connecting member 2 is driven in rotation, while ensuring adequate guidance of the corresponding unidirectional transmission member 18, 20.

[0041] A person skilled in the art will not encounter any particular difficulty in adapting the shape of the arms according to his own needs and, in particular, in modifying the number of flexible portions without departing from the scope of the present invention as defined by the claims.

[0042] In the case where the transmission mechanism comprises two arms 8, 10, the latter can advantageously have an angle of the order of 70 to 110 degrees between them but, of course, the person skilled in the art will also be able to adapt this indicative value according to the shape finally chosen to produce the arms and according to the number of flexible portions that they will comprise. In this regard, it will also be noted that the two arms do not necessarily comprise the same number of flexible portions.

[0043] There figure 2represents a simplified perspective view of a part of a transmission mechanism 1 according to a preferred embodiment of the present invention, seen from a first face, allowing certain construction details to be better appreciated. In addition, the Figures 3a and 3b represent the same front view of the transmission mechanism 1 of the figure 2 , seen from its second side and in two different respective operating phases.

[0044] According to this embodiment illustrated by way of non-limiting illustration, the connecting member 2 is associated with a toothed drive board 40, integral in rotation with the base 6, to define a transmission wheel set. The drive board 40 is intended to have, via its teeth, a kinematic connection with the driving wheel set, for example a winding mass, to ensure the driving of the base 6 and therefore of the arms 8, 10.

[0045] Alternatively, the drive board 40 may of course be made in one piece with the base 6 without departing from the scope of the invention and / or may include other means of connection with the driving mobile. Indeed, other modes of connection between the connecting member 2 and the driving mobile may be implemented without departing from the scope of the invention.

[0046] The output wheel set 4 comprises a drive surface defined by the periphery of a first driven wheel 42, arranged to cooperate by friction with peripheral contact surfaces of unidirectional transmission members 48, 50, and secured to a driving toothed wheel 44, intended to have a kinematic connection with a driven wheel set (not shown), for example a ratchet for winding a barrel spring. Thus, the unidirectional transmission members 48, 50 are intended to drive the first driven wheel 42 in a single direction of rotation, such that the driving toothed wheel 44 can rotate the driven wheel set in a single direction, regardless of the direction of rotation of the driving wheel set. Alternatively, the driven wheel set could be driven directly by the output wheel set 4.

[0047] It will be noted that the unidirectional transmission members 48, 50 have a different shape here from that illustrated in the figure 1 . In fact, each of these organs has the shape of a skate with a slight asymmetry in reference to its median plane. It appears from a careful examination of the Figures 3a and 3b that each skate has a slightly larger radius to the left of its median plane than to the right.

[0048] The drive board 40 is arranged in engagement with an intermediate connecting mobile 52 intended to be driven in rotation by the driving mobile. According to the embodiment illustrated in the figures 2 , 3a and 3b , without limitation, it is provided that the driving mobile performs small oscillations around an equilibrium position, in such a way that the intermediate connecting mobile 52 is driven to present back and forth movements, as is the connecting member 2.

[0049] There Figure 3aillustrates the operation of the transmission mechanism 1 when the intermediate connecting wheel 52 is rotated clockwise. The connecting member 2 is then rotated counterclockwise and the distal ends of the arms 8, 10 move away from the base 6 of the connecting member 2. In this case, the unidirectional transmission member 50 cooperates with the first driven wheel 42 so as to pivot in the clockwise direction of rotation, while the member 48 pivots in the counterclockwise direction of rotation, in the view of the Figure 3a. The member 50 in this case has an increasing radius opposite the first driven wheel 42, while the member 48 has a decreasing radius opposite this same wheel 42. Consequently, the member 50 enters into a bracing-type relationship with the first driven wheel 42, while the member 48 is free to rotate without acting on this same wheel 42. This results in the first driven wheel 42 being driven in the clockwise direction of rotation in the view of the Figure 3a , as illustrated by arrow H.

[0050] There Figure 3billustrates the operation of the transmission mechanism 1 when the intermediate connecting wheel 52 is rotated in the counterclockwise direction. The connecting member 2 is then rotated in the clockwise direction and the distal ends of the arms 8, 10 approach the base 6 of the connecting member 2. In this case, the unidirectional transmission member 50 cooperates with the first driven wheel 42 so as to pivot in the counterclockwise direction of rotation, while the member 48 pivots in the clockwise direction of rotation, in the view of the Figure 3b. The member 48 in this case has an increasing radius opposite the first driven wheel 42, while the member 50 has a decreasing radius opposite this same wheel 42. Consequently, the member 48 enters into a bracing-type relationship with the first driven wheel 42, while the member 50 is free to rotate without acting on this same wheel 42. This again results in the first driven wheel 42 being driven in the clockwise direction of rotation in the view of the Figure 3b , symbolized by the arrow H.

[0051] As already explained previously, at each change of direction of rotation, the unidirectional transmission member 48, 50 which is in an arching relationship with the first driven wheel 42 leaves this state by quickly presenting a decreasing radius allowing it to pivot without interacting with the first driven wheel 42. Conversely, the other unidirectional transmission member quickly presents an increasing radius to the first driven wheel 42 and enters into an arching type relationship with it.

[0052] Thanks to the characteristics just presented, a clockwork mechanism is obtained for transmitting a rotational movement between a driving wheel and a driven wheel, with unidirectional conversion, presenting a construction and a method of assembly that are at the same time simple, precise and reliable. In addition, this mechanism operates with less friction than the previous solution described above and thus offers excellent efficiency.

[0053] The implementation of the present invention is not limited to the exact geometry of the various components of the mechanism as illustrated and described. Indeed, a person skilled in the art will not encounter any particular difficulty in adapting the present teaching to the implementation of a transmission mechanism meeting the characteristics of the present invention, by implementing a number of arms of the connecting member adapted to his own needs, as well as the number and location of their flexible portions, or even the shape of the unidirectional transmission members or their method of installation in the transmission mechanism.

[0054] As already stated above, such a transmission mechanism is perfectly suited to integration into an automatic winding mechanism for transmitting the bidirectional movements of a winding mass to a mechanical energy storage member, but it may be implemented in relation to any other type of suitable watchmaking system without departing from the scope of the invention as defined by the appended set of claims. It will be noted in this case that the winding mass may advantageously be arranged to exhibit oscillating movements of low amplitude, preferably less than 20 degrees, more preferably less than 10 degrees, to promote the construction of a compact automatic winding mechanism.

Claims

1. Transmission mechanism (1), for a horological movement, intended to transmit the movements of a driving mobile to a driven mobile of the horological movement, the mechanism (1) comprising a transmission mobile comprising a drive plate (40), intended to be kinematically connected to the driving mobile and to pivot about a first fixed axis of rotation in response to the movements of the driving mobile, as well as a connecting member (2) having a flexible portion (36) and carrying a unidirectional transmission member (18, 20) arranged to cooperate with a drive surface of an output mobile (4) intended to be connected to the driven mobile, and to drive it when the driving mobile moves in a first direction of displacement, said connecting member (2) comprising a base (6) integral with said drive plate (40) and arranged to exhibit a rotational movement along said first fixed axis of rotation, in response to the movements of the driving mobile, the transmission mechanism (1) being so arranged that said connecting member (2) comprises a first arm (8, 10) extending from said base (6) and carrying said unidirectional transmission member (18, 20) at its distal end, said flexible portion (36) being arranged on said arm (8, 10) so as to allow deformation of the latter when said connecting member (2) is rotated.

2. Mechanism (1) according to claim 1, characterized in that said arm (8, 10) carries at least one additional flexible portion (36).

3. Mechanism (1) according to claim 1 or 2, said output mobile (4) being intended to be pivoted along a second fixed axis of rotation (30), characterized in that said distal end of said arm (8, 10) is integral with a radial guide arm (26, 28) arranged to pivot along said second fixed axis of rotation (30) while being free to rotate with reference to said output mobile (4).

4. Mechanism (1) according to claim 3, characterized in that said unidirectional transmission member (18, 20) is arranged on said distal end so as to be pivotable with reference thereto, along a third movable axis of rotation (22, 24), and carries a contact surface arranged to present an over-center locking relationship with said drive surface of said output mobile (4), so: that said contact surface drives said drive surface in a first direction of relative rotation between said radial guide arm (26, 28) and said output mobile (4), and that said contact surface moves without driving said drive surface in the opposite direction of relative rotation between said radial guide arm (26, 28) and said output mobile (4).

5. Mechanism (1) according to claim 4, characterized in that said arm (8, 10) or said radial guide arm (26, 28) carries an elastic return member (32) arranged to act on said unidirectional transmission member (18, 20) and tend to position it in a predefined rest position.

6. Mechanism according to one of the preceding claims, characterized in that said connecting member (2) carries a second arm (8, 10), having similar structural characteristics to said first arm (8, 10) and carrying an additional unidirectional transmission member (18, 20), arranged to drive said drive surface of said output mobile (4) when the driving mobile moves in a second direction of displacement, opposite to said first direction of displacement.

7. Mechanism according to claim 6, characterized in that said first and second arms (8, 10) extend along respective general directions inclined to one another by an angle of between 70 and 110 degrees.

8. Automatic winding mechanism comprising a transmission mechanism (1) according to one of claims 1 to 7, characterized in that it comprises a winding mass intended to be mounted on a frame element of the horological movement so as to be able to pivot with reference to the latter and having a kinematic connection with said drive plate (40).

9. Winding mechanism according to claim 8, characterized in that said winding mass is arranged to exhibit oscillating movements of low amplitude, preferably less than 20 degrees, more preferably less than 10 degrees.

10. Horological movement comprising a transmission mechanism (1) according to one of claims 1 to 7.

11. Horological movement comprising a winding mechanism according to claim 8 or 9, said output mobile (4) comprising a toothed driving mobile (44) having a kinematic connection with one end of an elastic mechanical energy storage member so as to be able to load the latter.

12. Timepiece comprising a horological movement according to claim 10 or 11.

Images