Mechanical clock movement

Abstract

A clockwork movement according to the invention comprises a control stem (3) which is movable by pulling the stem in the axial direction, a resonator (4) comprising a rotatable balance (10) mounted on flexible blades, and a mechanism for being able to interrupt the oscillation of the balance. The mechanism comprises a lever (23) connected to the stem, such that the lever pivots about a pivot axis (24) when the stem is pulled or pushed, and an auxiliary lever (30) connected to the lever such that the pivoting of the lever generates a rotation of the auxiliary lever about a rotation axis (31) which is distant from the pivot axis (24). The auxiliary lever is arranged such that, during its angular travel from a rest position, it stops the balance (10), independently of the position of the balance at the moment when the traction on the stem (3) is initiated.Furthermore, in the active position, the lever (30) holds the balance in a stationary position which allows the resonator (4) to restart automatically when the auxiliary lever (30) returns from the active position to the rest position.

Description

Technical field

[0001] The invention relates to a timepiece movement comprising a mechanical resonator and provided with a mechanism which makes it possible to stop the resonator, in particular when setting the time of the movement, and then to restart this resonator. In particular, the invention relates to a mechanical movement incorporating a mechanical oscillator formed from a mechanical resonator with flexible guidance and an escapement. The invention also relates to a timepiece, such as a watch, equipped with such a movement. Technological background

[0002] Many mechanical watches are equipped with a stop lever whose purpose is to stop the watch's resonator during the time setting process. Conventional stop levers are generally composed of a lever interacting with the balance wheel and connected to the winding stem directly, or indirectly by an intermediate part (pull, lever, or other). Although this system works correctly in a large number of movements, its application is less obvious in cases where the balance wheel is located quite far from the stem and / or the bulk of the movement makes access to the balance wheel difficult.

[0003] Furthermore, in mechanical watches, flexible-guided resonators overcome the chronometric problems associated with the use of balance springs with pivots. However, these resonators, due to their greater rigidity, are difficult to start since the torque at the escapement, in static mode, is not always sufficient to overcome the restoring force of the flexible guide. A disadvantage associated with this type of resonator is therefore that it is often necessary to shake the watch vigorously to start the resonator in the absence of specific means provided to wind the resonator at least to a lower limit angle from which it can be maintained by the escapement once it is released at start-up. Summary of the invention

[0004] The invention aims to provide a timepiece movement, provided with a flexibly guided resonator, which does not suffer from the drawbacks described above. In particular, it is intended to provide an immobilization mechanism capable, on the one hand, of stopping a flexibly guided mechanical resonator (i.e. immobilizing its balance) and, on the other hand, of winding the resonator at rest at least to a lower limit angle from which it can start without having to be subjected to acceleration, in particular by applying an accelerated movement to the timepiece which incorporates the timepiece movement.

[0005] For this purpose, the watch movement includes: a control stem which is movable in its axial direction between a winding position, also called 'pushed position', and a time-setting position, also called 'pulled position', a mechanical resonator with flexible guidance comprising a balance capable of oscillating around an oscillation axis between two extreme angular positions which the balance can reach respectively on both sides of an equilibrium position of the mechanical resonator, a mechanism for immobilizing the mechanical resonator arranged to be able to interrupt an oscillation of the balance when the stem is pulled towards the time-setting position, and to maintain the balance in an immobilized position as long as the stem remains in the time-setting position,

[0006] The immobilization mechanism comprises a lever in kinematic relation with the stem, so that the lever undergoes a pivoting in a first direction about a pivoting axis when the stem is pulled towards the time-setting position from its winding position and in the second direction when the stem is pushed from the time-setting position towards the winding position, and an auxiliary lever connected to the lever so that the pivoting of the lever in said first direction or said second direction generates a rotation of the auxiliary lever, respectively in a given direction and in an opposite direction, about a rotation axis which is distant from the pivoting axis, said rotation of the auxiliary lever thus being carried out reversibly between a rest position and an active position as a function of the axial displacement of the stem between the pushed position and the pulled position,the flexibly guided mechanical resonator being arranged so as to be able to start without the application of an external force torque from a limit angular position on each of the two sides of said equilibrium position. According to the invention, the balance comprises a part forming a stop for the auxiliary lever, the auxiliary lever being configured and its angular path, between said rest position and said active position, being designed so that, when the lever performs this angular path, the lever enters an annular zone, centered on the oscillation axis at the stop and defined radially by this stop, before passing through a position of extreme contact with said stop, corresponding to an extreme angular position of the balance on one side of the equilibrium position of this balance, and that then the lever remains in this annular zone until it reaches its active position for which the balance,once in contact with the lever via the stop, is in the immobilization position which is located on the other side of the equilibrium position and beyond the limiting angular position of this other side.,

[0007] According to an advantageous embodiment, the control rod and the immobilization mechanism are arranged in such a way that, when a user presses axially on the control rod with sufficient force to allow it to move from the pulled position to the pushed position, the part of the lever located in said annular zone moves more quickly in this annular zone than the stop of the balance, so that the balance is not braked by the lever when starting from the immobilization position.

[0008] According to a first particular embodiment, the balance comprises at least two annular segments forming an inertia mass, a lateral surface of one of the two annular segments forming the stop of the balance. According to a second particular embodiment, the balance comprises an annular rim, forming a complete circle, or at least two annular segments, the annular rim or one of said annular segments being provided with a part which rises axially or radially from this annular rim or this annular segment and which forms the stop. According to a third embodiment, the balance comprises an annular rim, forming a complete circle, or annular segments which is / are carried / carried by arms, one of these arms being provided with a projecting part which rises axially and which forms the stop.

[0009] The invention makes it possible to stop the balance wheel and immobilize it at an angular immobilization position, also called 'immobilization position', which then ensures automatic start / restart of the flexibly guided mechanical resonator. The invention also makes it possible to start the oscillation of the mechanical oscillator, when this oscillator is initially stopped at its equilibrium / zero position, by simply actuating the control stem (winding stem). The invention effectively and safely solves the problem of the mechanical oscillator not starting, which is typical for watch movements provided with flexibly guided resonators. Brief description of the figures

[0010] The invention will be described below in more detail with the aid of the appended drawings, given as non-limiting examples, in which: THE Figures 1 and 2represent front and back views of a part of a watch movement according to an embodiment of the invention, operating in time indication mode (winding stem pushed, in winding position). figure 2 , some components have been removed in order to visualize the components that are relevant to the invention. The Figures 3 and 4 represent front and back views of the movement represented in Figures 1 and 2 , when the winding stem is partially pulled out. The Figures 5 and 6 represent front and back views of the movement represented in Figures 1 and 2 , when the winding stem is fully pulled out and is in a time-setting position with the mechanical resonator stopped. Detailed description of the invention

[0011] The invention will be described on the basis of a specific embodiment shown in the figures and which does not limit the scope of the invention. Figures 1 and 2represent partial front and back views of a mechanical watch movement 1 according to a preferred embodiment of the invention. Certain constituent elements of the watch movement 1 are recognizable by those skilled in the art, in particular: a plate 2, a winding / control stem 3, a mechanical resonator 4 with flexible guidance.

[0012] The mechanical resonator 4 comprises a balance 10 supported by a set of flexible blades 11, arranged to allow oscillation of the balance around an oscillation axis 5. The structure of the balance 10 is typical for resonators with flexible guidance, the balance comprising two diametrically opposed arms 8, with two annular segments 9, forming an inertial mass, carried respectively at the outer ends of the two arms 8. The oscillation of the balance 10 is maintained by means of an escapement mechanism comprising an escape wheel 12 and an anchor 13 arranged rotatably between two limiting pins 14. In known manner, the escape wheel 13 is connected to the wound barrel (not shown) of the movement by a system of toothed wheels (not shown).Also in known manner, the interactions between resonator 4 and anchor 13 and between anchor 13 and escape wheel 12 will release the energy of the barrel in a controlled manner, so that movement 1 can indicate the time by means of rotating hands relative to a dial. The position of balance wheel 10 as shown in . figure 1 corresponds to the equilibrium position of the pendulum, relative to which the oscillation occurs from one side to the other side. We see in the figure 2 that at this moment, the anchor 13 is located centrally between the two limiting pins 14.

[0013] The controlled release of energy as described above is interrupted when the watch is set, carried out by pulling on the winding stem 3, followed by manual rotation of the latter.

[0014] THE Figures 3 and 4represent the movement 1 during a partial pull of the control stem 3. This stem 3 is connected to a connecting element called the pull 20. The pull applied to the stem 3 causes the pull 20 to tilt relative to the plate 2 around a pivot axis 21. A pin 22 fixedly mounted on the pull 20 interacts with a lever 23 so that the pull on the stem 3 causes this lever 23 to pivot relative to the plate 2, around a pivot axis 24. More generally, the lever 23 is in kinematic relation with the stem 3 so that the lever undergoes a pivoting in a first direction around the pivot axis when the stem is pulled towards the time-setting position (also called 'pulled position'), from its winding position (also called 'pushed position') and in the second direction when the stem is pushed from the time-setting position towards the winding position reassembly.

[0015] The rocker 23 comprises two wings 23a and 23b substantially opposite with respect to the pivot axis 24. The first wing 23a comprises an oblong opening 25 in which the pin 22 is arranged, while the opposite wing 23b is provided with a toothed section 26 (also called a rake) at its end. An auxiliary lever 30 is arranged on the plate 2 in a rotatable manner, this lever 30 being able to rotate about a rotation axis 31 which is distant from the pivot axis 24 of the rocker 23. The lever 30 is integral with a pinion 32 forming a gear transmission with the toothed section 26 of the rocker 23.In other words, the auxiliary lever 30 is kinematically connected to the lever 23 so that the pivoting of the lever in said first direction or said second direction generates a rotation of the auxiliary lever respectively in a given direction and in an opposite direction, around the rotation axis 31 which is distant from the pivot axis 24, said rotation of the auxiliary lever 30 thus being carried out reversibly between a rest position and an active position depending on the axial displacement of the stem 3 between the winding position (pushed position) and the time-setting position (pulled position).

[0016] Returning to the Figures 1 and 2, we see that the auxiliary lever 30 is folded onto the rocker 23 when the stem 3 is in the pushed position, which corresponds to the normal operating mode of the movement, i.e. the autonomous time indication mode by continuous oscillation of the balance 10. This folded position of the lever 30 represents the rest position of the lever. It will be noted that the Figures 1 and 2 represent the pendulum 10 in its equilibrium position, corresponding by definition to an angle zero / 0°.

[0017] By pulling the rod 3, the auxiliary lever 30 is unfolded in the direction of the pendulum 10. The Figures 3 and 4represent the instant when the lever 30 comes into contact with one of the annular segments 9 of the balance 10, more generally with a part of the balance forming a stop in the angular direction of this balance. In a first particular embodiment, a variant of which is shown in the figures, the balance 10 comprises at least two annular segments forming an inertia mass, a lateral surface of one of the annular segments forming a stop 36 of the balance for the lever. The position of the balance 10 at the moment of contact with the lever depends on the position of the balance at the moment when the user initiates actuation of the lever by pulling the rod 3 and also on the speed of this actuation.The oscillation of the balance, in particular the maximum amplitude of this oscillation, and the configuration of the balance, on the one hand, and the gearing between the rocker 23 and the pinion 32 as well as the configuration of the lever 30 and its angular path, on the other hand, are designed so that said contact between the stop 36 and the lever 30 takes place in any case during the deployment of the lever 30, independently of the angular position of the balance 10 when the lever enters an annular zone defined radially by the stop 36 and centered on the oscillation axis 5 at the stop, that is to say an annular zone whose outer radius and inner radius are determined by the two ends of the stop in the radial direction.This annular zone is a circular contact zone between the lever and the balance stop, namely a continuous geometric zone over 360°, defined by the stop 36 at the level of the latter along the oscillation axis, within which contact can occur between the stop 36 and the lever 10. Conventionally, a mechanical resonator with flexible guidance in a watch movement has an oscillation amplitude much smaller than the amplitude of a usual sprung balance, the maximum oscillation amplitude of the mechanical resonator with flexible strips being generally less than 60°. In the variant shown in the figures, the maximum oscillation amplitude is approximately 30°. In the context of the present invention, the maximum amplitude of the oscillation of the mechanical resonator is advantageously less than or equal to 45°. When the balance 10 comes into contact with the lever 30, the oscillation of the balance is interrupted, i.e.lever 30 stops the oscillation of pendulum 10.

[0018] THE Figures 3 and 4 represent the balance 10 in an extreme angular position -θ M , corresponding to the maximum amplitude θ M that the balance can have on the negative angle side (clockwise from the zero position of the balance). It can be seen that in this extreme angular position of the balance, the lever 30 has penetrated into said annular zone, defined radially by the stop 36, beyond this stop, that is to say at an angle which is greater, in absolute value, than the angular position of the stop corresponding to the maximum amplitude θ M of the balance on the negative angle side (in the variant shown). Thus, if the lever comes into contact with the balance in the extreme angular position on the negative angle side, as shown in Figures 3 and 4, the lever is then pressed against the stop 36. Then, the lever 30 is arranged in the watch movement and configured so that this lever remains partially in said annular zone, defined by the stop 36, until it has reached its final position, previously called the active position of the lever. In this final / active position of the lever ( Figures 5 and 6), when the balance stop is resting against the lever, the balance 10 is in an angular immobilization position θ R on the side of the positive angles relative to the zero position (0°) of the balance. Consequently, the lever 30 is arranged to be able to move angularly, in the positive direction (variant shown), the balance by continuing its angular path, around its axis of rotation 31, towards its final / active position and then maintain the balance in the angular immobilization position, corresponding to the final / active position, as long as the control stem is in the time-setting position.

[0019] Continuing the traction on rod 3 from the situation shown in Figures 3 and 4 , the lever 30 completes its angular path to its final / active position, shown in Figures 5 and 6. During the continuation of said angular path, the lever pushes the balance 10 in front of it and, in its final position, also called 'active position', the lever immobilizes the balance in an angular immobilization position θ R which is greater, in absolute value, than a lower limit angle θ L , also called 'limit angular position', from which the balance 10 can be maintained by the escapement once it is released at start-up or restart, i.e. a limit angular position θ L from which the mechanical oscillator with flexible blades starts automatically, without any restoring force other than that of the flexible blades, after having been stopped in its immobilization position or, in another case, in its 0° equilibrium position and then brought into the immobilization position by the lever by actuating the control stem.In other words, the lever 30 is configured and its angular path is provided in such a way that, when the lever makes an angular path between its initial / rest position and its final / active position, it enters said annular zone, defined radially by said stop of the balance, before passing through an angular position of contact with said stop, corresponding to an extreme position of the balance on one side of the equilibrium position of this balance, and that then this lever remains in the annular zone until it reaches its final / active position for which the balance is in the immobilization position on the other side of the equilibrium position, beyond the limit angular position of this other side.Thus, the lever makes, during its angular path, a journey inside said annular zone at an angle, relative to the oscillation axis, which is greater than the maximum amplitude of the oscillating balance and in fact greater than the sum of this maximum amplitude with the angular value of the limit angular position.

[0020] In conclusion, when the lever performs said angular path (in the forward direction), it comes into contact with the stop 36 of the balance if this balance is in an angular position corresponding to that of the lever, whatever this angular position between an extreme angular position of the balance, on one side of its zero position / equilibrium position (in the variant shown this is the extreme angular position -θ M on the side of the negative angles) and an angular position of immobilization θ R of this balance located on the other side of the zero position / equilibrium position and beyond said limit angular position, i.e. beyond the lower limit angle θ L in the variant shown, relative to the zero position / equilibrium position (the angular position of immobilization has an absolute value greater than that of said limit angular position / said lower limit angle on said other side of the zero position / equilibrium position).In all cases, whatever the angular position of the balance during said angular travel of the lever, this lever ends up immobilizing the balance 10 in a wound state at said angular immobilization position, i.e. a state which allows the balance to start or restart an oscillation maintained by the escapement as soon as the lever 30 is removed from its active position and from said annular zone without external intervention other than the actuation of the stem 3, by pushing this stem towards its winding position. The only measure particular to this automatic starting or restarting of the balance, also called 'self-starting', is a withdrawal of the lever from said annular zone (annular contact zone between the lever and the balance stop) which is faster than the speed of the stop 36 during a free movement of the balance 10 from its angular immobilization position θ R from which it starts with an initial speed of zero (balance stop state).It will be noted that, by "automatic" and "self-start", we understand a start or restart, generally called 'start', which occurs following the actuation of the winding / control stem from its time-setting position (pulled out position) to its winding position (pushed in position) under the sole constraint exerted by the flexible blades on the balance, i.e. with the sole torque applied by the flexible blades to the balance, from the immobilization position of the balance provided within the scope of the invention.

[0021] To achieve this self-start function, the angular position of the immobilized pendulum, defined in relation to the equilibrium position of its oscillation (position shown in figure 1), must generally exceed half of the balance wheel lift angle. This lift angle is a characteristic parameter of the resonator and the concept of the lift angle is well known to those skilled in the art. In the specific resonator shown in the figures, the lift angle is approximately 14° (7° on both sides of the equilibrium position) and said lower limit angle corresponds, in absolute value, to half of the lift angle, i.e. approximately 7°. The balance wheel standstill position is approximately 10° from the equilibrium position (zero position / 0°), which ensures the desired self-starting.

[0022] As mentioned, the lever 30 can stop the balance 10 at any time during the oscillation path of the balance. In most cases, after the first contact between the lever 30 and the balance stop, the lever pushes the balance towards its stopping position. Preferably, the lever 30 is designed in terms of shape, material, flexibility, etc. so that during this phase following the first contact, the lever remains in contact with the balance, i.e. the impact between the lever and the balance is such that the balance does not experience a significant rebound on the lever, but rather is accompanied by the lever 30 towards its stopping position.However, embodiments in which this impact would cause a rebound, or even rebounds of the balance stop on the lever following a first impact are not excluded from the scope of the invention, provided that after the initial impact the balance ends up coming to a standstill in the intended angular immobilization position, and that it is then held in this immobilization position by the lever.

[0023] While the lever 30 holds the pendulum 10 in its immobilized position as shown in Figures 5 and 6, the user can set the time of his watch by turning the control stem 3 in a manner known per se. Then, by pushing the stem 3, the lever 30 is withdrawn from its active position and returns to its rest position, which allows the balance 10 to oscillate again. As already mentioned, to prevent the lever 30 from disturbing the self-starting, it must be withdrawn sufficiently quickly. The folding speed of the lever 30 is linked to the pivoting speed of the lever 23 and to the gearing between the toothed end 26 of the lever 23 and the pinion 32 secured to the lever. This system is preferably designed so that the rotation speed of the pinion 32, and therefore of the lever 30, clearly exceeds the pivoting speed of the lever 23 and the folding / retraction of the lever is faster than the balance in the starting phase.Thus, the folding / retraction of the lever always occurs sufficiently quickly, even if the rod 3 would be pushed by a user more slowly than normally towards its winding position (pushed position), although such an action is not intended. According to embodiments, the rotation speed of the lever 30 is at least double, preferably at least triple the pivoting speed of the rocker.

[0024] Since the rotational speed of the lever 30 significantly exceeds the pivoting speed of the rocker 23, the angular path of the lever is significantly greater than the corresponding angular path of the rocker, which also allows the lever to interact with the balance 10 over a distance which is sufficiently large so that the balance can, from any angular position, be immobilized in an angular immobilization position greater than a lower limit position which allows self-starting, as explained previously.

[0025] The invention is intended for a movement provided with a flexible-guided resonator, since it provides a particular benefit to configurations comprising this type of resonator. This benefit is linked more particularly to the self-starting aspect described above. There is effectively no longer any need to shake the watch to start or restart the mechanical oscillator comprising the flexible-blade mechanical resonator. The invention is also applicable to a balance wheel provided with a continuous annular rim, in the shape of a complete circle. In this case, provision is made for the arrangement of a stop, for example a pin, on the balance wheel, which extends radially or axially from the rim, alternatively axially from one of the arms of the balance wheel, and which can come into contact with the auxiliary lever 30 unfolded in the manner described above.In a second particular embodiment, the balance comprises an annular rim, forming a complete circle, which is provided with a projecting part which rises axially or radially from this annular rim and which forms said stop. In a third particular embodiment, said stop is formed by a projecting part which rises axially from one of the arms carrying the annular segments or alternatively the annular rim.

[0026] A general benefit of the invention is that the immobilization mechanism, with its two-part system, makes it easier to reach the balance wheel if it is far from the stem or if the size of the movement does not allow direct access. In addition, it makes it possible to enter into functional contact with the balance wheel regardless of its initial angular position. Indeed, it is important that the actuation of the control stem can be done at any time and that the interaction between the immobilization mechanism (more generally the stop and self-start mechanism) and the balance wheel is always functional.

Claims

1. Watch movement comprising: - a control stem (3) which is movable in its axial direction between a winding position, also called 'pushed position', and a time-setting position, also called 'pulled position', - a mechanical resonator (4) with flexible guidance comprising a balance (10) capable of oscillating around an oscillation axis (5) between two extreme angular positions which the balance can reach respectively on both sides of an equilibrium position (0°) of the mechanical resonator, - a mechanism for immobilizing the mechanical resonator arranged to be able to interrupt an oscillation of the balance when the stem (3) is pulled towards the time-setting position, and to maintain the balance in an immobilization position as long as the stem remains in the time-setting position, said immobilization mechanism comprising a lever (23) in kinematic relation with the stem (3),such that the lever pivots in a first direction about a pivot axis (24) when the stem is pulled towards the time-setting position from its winding position and in the second direction when the stem is pushed from the time-setting position towards the winding position, and an auxiliary lever (30) connected to the lever (23) such that the pivoting of the lever in said first direction or said second direction generates a rotation of the auxiliary lever, respectively in a given direction and in an opposite direction, about a rotation axis (31) which is distant from the pivot axis (24), said rotation of the auxiliary lever (30) thus being carried out reversibly between a rest position and an active position depending on the axial displacement of the stem (3) between the pushed position and the pulled position,the flexibly guided mechanical resonator being arranged so as to be able to start without the application of an external force torque from a limiting angular position on each of the two sides of said equilibrium position; characterized in that the balance comprises a part forming a stop (36) for the auxiliary lever (30), the auxiliary lever being configured and its angular path, between said rest position and said active position, being designed so that, when the lever performs this angular path, the lever enters an annular zone, centered on the oscillation axis at the stop and defined radially by this stop, before passing through a position of extreme contact with said stop (36), corresponding to an extreme angular position (-θ M) of the balance on one side of the equilibrium position (0°) of this balance, and that then the lever remains in this annular zone until it reaches its active position for which the balance, once in contact with the lever via the stop, is in said immobilization position (θ R ) which is located on the other side of the equilibrium position and beyond the limiting angular position (θ L ) on this other side.

2. Watch movement (1) according to claim 1, characterized in that the auxiliary lever (30) is connected to the rocker (23) so that the rotation speed of the auxiliary lever is at least twice the pivoting speed of the rocker.

3. Watch movement (1) according to claim 1 or 2, characterized in that the auxiliary lever (30) is connected to the rocker (23) by a gear transmission.

4. Watch movement (1) according to any one of the preceding claims, characterized in thatthe control rod and the immobilization mechanism are arranged in such a way that, when a user presses axially on the control rod with sufficient force to allow it to move from the pulled position to the pushed position, the part of the lever located in said annular zone moves more quickly in this annular zone than the stop of the balance, so that the balance is not braked by the lever when starting from the immobilization position.

5. Watch movement (1) according to any one of the preceding claims, characterized in that the auxiliary lever (30) is connected to the rocker (23) so that the angular path described by the lever (30) between its rest position and its active position is greater than the corresponding angular path described by the rocker (23).

6. Watch movement (1) according to claim 5, characterized in thatsaid angular path of the lever is at least twice as large as said angular path of the rocker.

7. Watch movement according to any one of the preceding claims, characterized in that the balance (10) comprises at least two annular segments (9) forming an inertial mass, a lateral surface of one of the two annular segments forming the stop of the balance.

8. Watch movement according to any one of claims 1 to 6, characterized in that the balance wheel comprises an annular rim, forming a complete circle, or annular segments, the annular rim or one of said annular segments being provided with a projecting part which rises axially or radially from this annular rim or this annular segment and which forms the stop.

9. Watch movement according to any one of claims 1 to 6, characterized in thatthe balance wheel comprises an annular rim, forming a complete circle, or annular segments which is / are carried / carried by arms, one of these arms being provided with a projecting part which rises axially and which forms the stop.

10. Watch characterized in that it comprises a watch movement according to any one of the preceding claims.

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