Patent Application
20220187767
This application claims priority to CH Patent Application No. 01599/20 filed Dec. 16, 2020, the entire contents of which is hereby incorporated by reference.
The present invention relates to a transmission mechanism, for a horological movement, intended to transmit the movements of a driving wheel to a driven wheel of the horological movement, the mechanism comprising a transmission wheel comprising a driving plate, intended to be linked kinematically to the driving wheel and to pivot about a first fixed axis of rotation in response to the movements of the driving wheel, and a link organ having a flexible portion and bearing a unidirectional transmission organ arranged to cooperate with a driving surface of an output wheel intended to be linked to the driven wheel, and to drive it when the driving wheel is displaced in a first direction of displacement.
According to a preferred embodiment, the invention relates to an automatic winding mechanism comprising a transmission mechanism of this type to make the link between a winding mass and a mechanical energy storage device.
The present invention relates also to a horological movement provided with such a transmission mechanism and a timepiece comprising such a horological movement.
Horological mechanisms of this type are already known in the prior art, in particular in relation to automatic winding mechanisms.
Thus, for example, the patent EP 3203326 B1 illustrates and describes a transmission mechanism matching the above features. More specifically, this transmission mechanism is intended to convert the bidirectional rotational movement of a winding mass into a unidirectional movement that makes it possible to ensure the winding of a barrel spring. To this end, the mechanism comprises a first rotary wheel intended to be driven by the movements of the winding mass, in one direction or in the other. This first wheel bears a transmission disc that is off-centre with respect to the axis of rotation of the first wheel and arranged to drive a transmission organ by a circular translational movement. The transmission organ cooperates in turn with a clutch organ arranged to allow a unidirectional rotational driving of an output wheel intended to be linked to an end of a barrel spring, to ensure the charging thereof. To this end, the transmission organ bears two driving surfaces that can have an over-centre link with the clutch organ, each of which is associated with a given direction of rotation. For each direction of rotation of the winding mass, the driving surfaces are alternately brought closer to and away from the clutch organ, in a to-and-fro motion, by virtue of the circular translational movement of the transmission organ. Thus, the driving surfaces cooperate alternately with the clutch organ to drive it in rotation in one and the same direction of rotation.
Such a construction requires great precision in production and in the positioning of the various components involved, to ensure that the trajectory of the driving surfaces makes it possible to effectively obtain the over-centre link targeted with the clutch organ.
One main aim of the present invention is to propose a horological transmission mechanism that has an alternative construction that is more compact and sensitively simplified compared to the conversion mechanism which has just been described.
To this end, the present invention relates more particularly to a transmission mechanism of the type indicated above, characterized
By virtue of these features, the arm of the link organ can be shaped and dimensioned, including for its flexible portion, so as to ensure good implementation of the unidirectional driving of the output wheel by the unidirectional transmission organ, while driving the link organ according to a simple rotational movement.
Preferably, the arm bears at least one additional flexible portion.
This feature provides the constructor of the mechanism with more flexibility with respect to the choice of form of the arm.
Generally, when the output wheel is intended to be pivoted about a second fixed axis of rotation, it is also possible to provide for the distal end of the arm to be secured to a radial guiding arm arranged to pivot about the second fixed axis of rotation while being free to revolve with reference to the output wheel.
In this case, it is also possible to provide for the unidirectional transmission organ to be arranged on the distal end so as to be able to pivot with reference thereto, about a third mobile axis of rotation, and bears a contact surface arranged to have an over-centre relationship with the driving surface of the output wheel, so that: the contact surface drives the driving surface in a first direction of relative rotation between the radial guiding arm and the output wheel, and the contact surface is displaced without driving the driving surface in the opposite direction of relative rotation between the radial guiding arm and the output wheel.
It is then advantageously possible to provide for the arm of the link organ or the radial guiding arm to bear an elastic return organ arranged to act on the unidirectional transmission organ and tend to position it in a predefined rest position.
Generally, provision can be made for the link organ to bear a second arm, having structural characteristics similar to those of the first arm and bearing an additional unidirectional transmission organ, arranged to drive the driving surface of the output wheel when the driving wheel is displaced in a second direction of displacement, opposite the first direction of displacement.
Such a construction is less restrictive from the point of view of the production of the components and their arrangement than in the prior art mechanism cited above, given that an arm bearing at least one flexible portion is associated with each of the unidirectional transmission organs.
In this case, it is advantageously possible to provide for the first and second arms to extend in respective general directions that are inclined with respect to one another by an angle of between 70 and 110 degrees.
According to a preferred variant embodiment, the present invention relates to an automatic winding mechanism comprising a transmission mechanism wholly or partly matching the features which have just been explained, and comprising a winding mass intended to be mounted on a frame element of the horological movement so as to be able to pivot with respect thereto and having a kinematic link with the driving plate.
In this case, it is preferably possible to provide for the winding mass to be arranged to exhibit oscillating movements of low amplitude, preferably less than 20 degrees, more preferably less than 10 degrees.
The present invention relates generally to a horological movement comprising a transmission mechanism matching the features set out above, whether or not it is incorporated in an automatic winding mechanism, and a timepiece comprising such a horological movement.
Other features and advantages of the present invention will emerge more clearly on reading the following detailed description of a preferred embodiment, given with reference to the attached drawings that are given by way of nonlimiting example and in which:
The following detailed description sets out to describe a horological transmission mechanism according to a preferred embodiment of the present invention as an illustrative and nonlimiting example. More specifically, according to the embodiment illustrated and described, the transmission mechanism is intended to be incorporated in an automatic winding mechanism of a timepiece, but, obviously, the person skilled in the art will be able to implement the transmission mechanism according to the invention in relation to other types of horological mechanisms without departing from the scope of the present invention as defined in the set of claims.
Generally, the transmission mechanism 1 according to the invention is intended to convert bidirectional rotational movements of a driving wheel (not represented) into unidirectional rotation movements of a driven wheel. To this end, the transmission mechanism 1 notably comprises a link organ 2 intended to be driven in bidirectional rotation from the movements of the driving wheel and to drive, in turn, an output wheel 4 according to a unidirectional rotational movement.
When the transmission mechanism 1 according to the invention is incorporated in an automatic winding mechanism, it can advantageously be arranged to convert the bidirectional rotational movements of a winding mass (not represented) into unidirectional rotational movements, before the latter are transmitted to a mechanical energy storage organ to charge it with mechanical energy, typically a barrel spring (not represented).
Returning to the schematic diagram of
The base 6 bears two arms 8, 10 extending in general directions that are inclined with respect to one another, towards a region close to the periphery of the output wheel 4, intended to be linked kinematically to the mechanical energy storage organ in the case of an automatic winding mechanism.
Each of the arms 8, 10 comprises, at its distal end, a support 14, 16 on which a unidirectional transmission organ 18, 20, having a general circular wheel form, is mounted to rotate, on an axis of rotation 22, 24. Finally, in the present examplary embodiment, a radial guiding arm 26, 28 is provided to link each support 14, 16 to the axis of rotation 30 of the output wheel 4 and thus maintain the corresponding axis of rotation 22, 24 at a constant distance from the axis of rotation 30.
It can be seen that each of the axis of rotation 22, 24 is slightly offset with respect to a radius passing through the axis of rotation 30 of the output wheel 4 and the point of contact thereof with the corresponding unidirectional transmission organ. Furthermore, each axis of rotation 22, 24 is preferably slightly off-centre with respect to the circular periphery of the corresponding unidirectional transmission organ, the circular periphery defining a contact surface with the output wheel 4.
Thus, it appears that, starting from the configuration illustrated in
The distance between the axis of rotation 22 of the unidirectional transmission organ 18 and the periphery of the output wheel 4 being kept constant, the pivoting of the unidirectional transmission organ 18 will give rise to an over-centre link with the output wheel 4 after a certain time, that is to say when its radius situated between its axis of rotation 22 and its point of contact with the periphery of the output wheel 4 becomes sufficiently great to prevent a free pivoting of the unidirectional transmission organ 18. From that instant, any subsequent rotation of the link organ 2 in the same direction of rotation (clockwise in the view of
Conversely, when the link organ 2 turns in the counterclockwise direction in the view of
It emerges from
In the configuration illustrated in
Conversely, a rotation of the link organ 2 in the counterclockwise direction of rotation drives a free rotation in the same direction of the unidirectional transmission organ 18, with reference to the output wheel 4. At the same time, the unidirectional transmission organ 20 revolves in the clockwise direction, which tends to place it in an over-centre link situation with the output wheel 4 to drive the latter in the clockwise direction of rotation.
Thus, whatever the direction of rotation of the link organ 2, the unidirectional transmission organs 18, 20 alternately ensure the driving of the output wheel 4 in one and the same direction.
It will be noted that a return spring 32 is preferably associated with each unidirectional transmission organ 18, 20, by cooperating with a pin 34 secured to the latter, to prevent its orientation from moving too far away from the orientation in which the over-centre interaction with the output wheel 4 occurs, and thus ensure a greater responsiveness of the transmission mechanism according to the invention, particularly upon changes of the direction of driving of the link organ 2.
Obviously, the principle of operation which has just been described can be implemented with a single arm bearing a single unidirectional transmission organ. In this case, when the transmission mechanism is incorporated in an automatic winding mechanism for example, only one direction of rotation of the winding mass will contribute to the charging of the mechanical energy storage organ.
According to a preferred embodiment of the invention, but in a nonlimiting manner, each of the arms 8, 10 has, between its proximal end secured to the base 6 of the link organ 2 and its distal end comprising the corresponding support 14, 16, two flexible portions 36 intended to allow the arm 8, 10 to be deformed when the link organ 2 is driven in rotation, while ensuring a suitable guiding of the corresponding unidirectional transmission organ 18, 20.
The person skilled in the art will have no particular difficulty in adapting the form of the arms according to its specific needs and, notably, to modify the number of flexible portions thereof without in any way departing from the scope of the present invention as defined by the claims.
In the case where the transmission mechanism comprises two arms 8, 10, the latter can advantageously have between them an angle of the order of 70 to 110 degrees but, obviously, the person skilled in the art will be able to also adapt this indicative value according to the form finally retained to produce the arms and according to the number of flexible portions that they include. In that respect, it will also be noted that the two arms do not necessarily comprise the same number of flexible portions.
Furthermore,
According to this embodiment illustrated as a nonlimiting illustration, the link organ 2 is associated with a driving plate 40, having teeth and secured in rotation to the base 6, to define a transmission wheel. The driving plate 40 is intended to have, via its teeth, a kinematic link with the driving wheel, for example a winding mass, to ensure the driving of the base 6 and therefore of the arms 8, 10.
Alternatively, the driving plate 40 will of course be able to be produced in a single piece with the base 6 without departing from the scope of the invention and/or will be able to comprise other link means with the driving wheel. In fact, other link methods between the link organ 2 and the driving wheel will be able to be implemented without in any way departing from the scope of the invention.
The output wheel 4 comprises a driving surface defined by the periphery of a first driven wheel 42, arranged to cooperate by friction with peripheral contact surfaces of unidirectional transmission organs 48, 50, and secured to a driving toothed wheel 44, intended to have a kinematic link with a driven wheel (not represented), for example a winding ratchet of a barrel spring. Thus, the unidirectional transmission organs 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 drive the driven wheel in rotation in one and the same direction and do so regardless of the direction of rotation of the driving wheel. Alternatively, the driven wheel could be driven directly by the output wheel 4.
It will be noted that the unidirectional transmission organs 48, 50 here have a different form from that illustrated in
The driving plate 40 is arranged engaged with an intermediate link wheel 52 intended to be driven in rotation by the driving wheel. According to the embodiment illustrated in
As already explained previously, on each change of direction of rotation, the unidirectional transmission organ 48, 50 which is in an over-centre relationship with the first driven wheel 42 leaves this state rapidly presenting a decreasing radius allowing it to pivot without interacting with the first driven wheel 42. Conversely, the other unidirectional transmission organ rapidly presents an increasing radius to the first driven wheel 42 and enters into an over-centre relationship therewith.
By virtue of the features which have just been presented, a horological mechanism is obtained for the transmission of a rotational movement between a driving wheel and a driven wheel, with unidirectional conversion that exhibits a construction and assembly mode that are at the same time simple, precise and reliable. Furthermore, this mechanism operates with less friction than the prior solution described above and thus offers an excellent efficiency.
The implementation of the present invention is not limited to the exact geometry of the various components of the mechanism as has been illustrated and described. In fact, the person skilled in the art will have no particular difficulty in adapting the present teaching to the implementation of a transmission mechanism matching the features of the present invention, by implementing a number of arms of the link organ suited to its specific needs, like the number and the placement of their flexible portions, or even the form of the unidirectional transmission organs or the way they are set out in the transmission mechanism.
As already specified above, such a transmission mechanism is perfectly suited to incorporation in an automatic winding mechanism to transmit the bidirectional movements of a winding mass to a mechanical energy storage organ, but it will be able to be implemented in relation to any other type of suitable horological system without departing from the scope of the invention. It will be noted in this case that the winding mass can advantageously be arranged to exhibit oscillating movements of a low amplitude, preferably less than 20 degrees, more preferably less than 10 degrees, to favour the construction of a compact automatic winding mechanism.
| Number | Date | Country | Kind |
|---|---|---|---|
| 01599/20 | Dec 2020 | CH | national |
