Timepiece mechanism

Abstract

The invention relates to a timepiece mechanism comprising an oscillator (1) with a flexible pivot, and a stop device (6) for stopping the oscillator (1), the oscillator (1) comprising: a base (20) for attaching the oscillator (1) to a stationary or mobile frame of a timepiece movement; an oscillating member (3, 21, 4) intended to oscillate in rotation about a virtual axis of rotation (A), the oscillating member (3, 21, 4) comprising a radial element (31, 21, 4) with respect to the virtual axis of rotation (A), the radial element (31, 21, 4) comprising at least one stop element (5a; 5a, 5b); and a flexible pivot (2a, 2b) for suspending the oscillating member (3, 21, 4) from the base (20) and defining the virtual axis of rotation (A); the stop device (6) comprising: a stop member (7) with at least one abutment (71); the stop member (7) being configured to be movable between an active position in which the at least one abutment (71) engages with the at least one stop element (5a; 5a, 5b) to lock the oscillating member (3, 21, 4) in a predetermined position in which the elastic return force of the flexible pivot (2a, 2b) is non-zero, and an inactive position in which the at least one abutment (71) is spaced apart from the path travelled by the at least one stop element (5a; 5a, 5b) during the oscillation of the oscillating member (3, 21, 4), the stop member (7) being configured such that, during the movement of the stop member (7) in a first direction from the inactive position to the active position, the at least one abutment (71) follows a circular trajectory centred about an axis parallel to the virtual axis of rotation (A), the at least one abutment (71) and the at least one stop element (5a; 5a, 5b) being configured so that, when the at least one abutment (71) engages with the at least one stop element (5a; 5a, 5b) to lock the oscillating member (3, 21, 4), the force exerted by the at least one abutment (71) on the at least one stop element (5a; 5a, 5b) is essentially tangential with respect to the rotational movement performed by the at least one stop element (5a; 5a, 5b) during the oscillation of the oscillating member (3, 21, 4), the stop member (7) being further configured to be returned from the active position to the inactive position in a second direction opposite to the first direction. The invention also relates to a timepiece movement comprising such a timepiece mechanism, and to a timepiece comprising such a timepiece movement.

Description

[0001] Clock mechanism

[0002] The present invention relates to a clockwork mechanism comprising a flexible pivot oscillator and a stopping device for stopping the oscillator.

[0003] A flexible pivot oscillator is an oscillator whose oscillating member, which includes the balance wheel, is guided in rotation by an arrangement of elastic parts and not by a physical axis of rotation sliding in bearings. In addition to its rotational guiding function, the flexible pivot exerts a restoring torque on the oscillating member, similar to the balance spring of a sprung balance oscillator.

[0004] Unlike sprung balance oscillators, a flexible pivot oscillator does not produce dry friction during operation. It therefore has a better quality factor.

[0005] The present invention relates to a watch mechanism comprising a flexible pivot oscillator whose arrangement of elastic parts comprises, for example, elastic blades extending in different parallel planes, for example so-called separate crossed elastic blades which cross in top view without touching each other. Such watch oscillators are described, for example, in patent applications EP 2911012, EP 2998800, EP 3382470, EP 3839651, EP 3410229, EP 3502784, US 2020 / 0033804, WO 2016 / 096677, WO 2017 / 055983, WO 2018 / 109584 and WO 2022 / 009102.

[0006] The watch mechanism of the invention also comprises a stop device for stopping the oscillator. An oscillator stop device, sometimes called a "balance stop", may be necessary to stop the oscillation of the oscillator of a mechanical watch to set the second hand by positioning it at 12 o'clock, from the control stem of the watch, in order to restart the movement at a precise moment, indicated for example by a time signal. An oscillator stop device may also be necessary to stop the oscillation of an oscillator dedicated to a chronograph. The oscillator then only starts moving when a time measurement is carried out and it must be stopped once the measurement has been made.

[0007] Traditionally used stop devices generally include a stop lever controlled, for example, by the time-setting position of the stem or by pressing a push button, to press radially against the rim of the balance wheel of the oscillating member in order to stop it. The disadvantage of such devices is that the angular position at which the oscillating member is stopped by the stop lever is random. In particular, there is a risk that the oscillating member will be stopped while the elastic parts have zero potential energy, so that the oscillator will not be able to restart itself once the stop lever is moved away from the balance wheel. This is particularly critical in the case of flexible pivot oscillators, the stiffness of whose elastic parts, typically elastic blades, generally do not allow them to self-start, particularly when they are associated with a Swiss lever escapement.Furthermore, if the oscillating member is stopped while the flexible pivot has non-zero potential energy, this energy will be different depending on the angular position of the oscillating member when it stops. As a result, the amplitude of the oscillating member may be different at each start, so that the restart will not be precise.

[0008] A solution for stopping a balance with a flexible pivot in a determined position was proposed by international application WO 2020 / 152578 A1 in which the balance comprises a felloe having, on its peripheral edge, a stop positioned so as to form with the center line an angle substantially equal to the stationary amplitude. When the stop lever is brought into contact with the felloe, it abuts against the stop and stops the balance in a determined angular position with non-zero potential energy in order to guarantee at each stop a precise and immediate restart at its stationary speed, with a stabilized amplitude. This solution does not worsen the overall size of the mechanism in height. On the other hand, the stop lever requires space at the periphery of the balance, in particular to allow its clearance when restarting the balance. Another disadvantage of this solution is that the stop lever is in radial support against the felloe of the balance.When the balance wheel stops, the elastic blades of the balance wheel are thus stressed longitudinally, in this case in traction, which risks causing their premature wear.

[0009] An aim of the present invention is to propose a clockwork mechanism comprising a flexible pivot oscillator and a stopping device making it possible to stop the flexible pivot oscillator in a determined position with sufficient non-zero potential energy to allow the oscillator to be restarted, while minimizing the mechanical stresses on the oscillator, in particular on the flexible pivot, when it is stopped.

[0010] Another object of the present invention is to provide a clockwork mechanism comprising a flexible pivot oscillator and a stop device whose bulk around the oscillator is minimal.

[0011] These and other objects are achieved by a timepiece mechanism comprising a flexible pivot oscillator, and a stopping device for stopping the oscillator, the oscillator comprising:

[0012] - a base for fixing the oscillator to a fixed or mobile frame of a watch movement;

[0013] - an oscillating member intended to oscillate in rotation about a virtual axis of rotation, the oscillating member comprising a radial element relative to the virtual axis of rotation, the radial element comprising at least one stop element; and

[0014] - a flexible pivot for suspending the oscillating member from the base and defining the virtual axis of rotation; the stopping device comprising:

[0015] - a stop member with at least one stop; the stop member being configured to be movable between an active position in which the at least one stop cooperates with the at least one stop element to block the oscillating member in a predetermined position in which the elastic return force of the flexible pivot is non-zero, and an inactive position in which the at least one stop is spaced from the path taken by the at least one stop element during the oscillation of the oscillating member, the stop member being configured so that during the movement in a first direction of the stop member from the inactive position to the active position, the at least one stop follows a circular path centered around an axis parallel to the virtual axis of rotation, the at least one stop and the at least one stop element being configured so that when the at least one stop cooperates with the at least one stop element to block the oscillating member,the force exerted by the at least one stop on the at least one stop element is essentially tangential to the rotational movement performed by the at least one stop element during the oscillation of the oscillating member, the stop member being further configured to be returned from the active position to the inactive position in a second direction opposite to the first direction.,

[0016] The force exerted by the stop on the stopping element when the oscillating member is blocked being essentially tangential, the position of the flexible pivot corresponds to a position in normal operation. The tensile or compressive stresses, which could cause premature wear of the flexible pivot, are practically zero. In addition, the stopping element being part of the radial element of the oscillating member, it is accessible by the stop between the virtual axis of rotation and the periphery of the oscillating member, thus limiting the space required around the mechanism of the invention necessary for the stopping device. The stop moving along a circular path in a plane parallel to the plane of the oscillating member, it is possible to stop the oscillating member whatever its angular position when the stopping device is actuated, the stop approaching the stopping element along a path similar to the path of the stopping element.Furthermore, since the potential energy of the oscillator in its rest position is non-zero, it allows the oscillator to restart by itself without an external impulse, for example from the stop member. The oscillator thus restarts by itself as soon as the stop member is returned in the opposite direction from its active position to its inactive position, and therefore removed from the path taken by the stop element during the oscillation. The restart of the oscillator is carried out without the need for an external impulse, which could destabilize the oscillator in its first oscillations after the restart.

[0017] The stop element is preferably located, in projection in a plane perpendicular to the virtual axis of rotation, between the virtual axis of rotation and the periphery of the oscillating member.

[0018] Preferably, the stop element extends radially relative to the virtual axis of rotation, perpendicular to the radial element.

[0019] According to certain embodiments, the stop element is a first finger and the radial element comprises a second finger extending radially relative to the virtual axis of rotation in a direction opposite to the direction of the first finger to compensate for the unbalance of the oscillating member induced by the first finger, the second finger being located, in projection in a plane perpendicular to the virtual axis of rotation, between the virtual axis of rotation and the periphery of the oscillating member.

[0020] The stop is for example a pin.

[0021] The stopping member is then, for example, a lever and the pin is arranged at one end of the lever.

[0022] According to certain embodiments, the stop member comprises two stops, and the radial element comprises two stop elements each extending radially relative to the virtual axis of rotation and in opposite directions, each stop cooperating with one of the two stop elements when the stop member is in the active position.

[0023] The stop member is for example a stop arm mounted in rotation about an axis of rotation preferably coincident with the virtual axis of rotation of the oscillating member, the two stops being arranged on either side of the axis of rotation, preferably at an equal distance from the axis of rotation. According to certain embodiments, the stop element extends in a plane perpendicular to the virtual axis of rotation and passing essentially through a center of gravity of the oscillating member.

[0024] Preferably, the flexible pivot comprises two crossed elastic blades without contact.

[0025] The base and the flexible pivot are for example manufactured by etching a silicon-based substrate.

[0026] The above-mentioned aims and other advantages are also achieved by a watch movement comprising such a watch mechanism and a control mechanism for controlling the stopping device of the watch mechanism.

[0027] The watch movement is for example a chronograph movement.

[0028] The above-mentioned aims and other advantages are also achieved by a timepiece comprising such a watch movement, for example a wristwatch.

[0029] The present invention will be better understood upon reading the following description, illustrated by the figures, where:

[0030] - Figure 1 is a perspective view of an embodiment of a flexible pivot oscillator for a clockwork mechanism according to the invention;

[0031] - Figure 2 is another perspective view of part of the oscillator of Figure 1;

[0032] - figure 3 illustrates a clockwork mechanism according to one embodiment of the invention, comprising the oscillator of figure 1;

[0033] - figure 4 illustrates a clockwork mechanism according to another embodiment of the invention, comprising the oscillator of figure 1;

[0034] - Figure 5 is a perspective view of another embodiment of a flexible pivot oscillator for a clockwork mechanism according to the invention;

[0035] - figure 6 shows a clockwork mechanism according to one embodiment of the invention, comprising the oscillator of figure 5; - figure 7 illustrates another embodiment of a clockwork mechanism according to the invention, comprising the oscillator of figure 5.

[0036] According to the invention, the clockwork mechanism comprises a flexible pivot oscillator, for example a flexible pivot oscillator such as that illustrated in Figures 1 and 2 as an illustrative, but in no way limiting, example. According to the illustrated embodiment, the oscillator 1 comprises a balance wheel 3 and a flexible support

[0037] 2. The flexible support 2 comprises a base 20 for fixing the oscillator 1 to a fixed or mobile frame of a watch movement, and a flexible pivot consisting of a first elastic blade 2a and a second elastic blade 2b connecting the base 20 to a suspension element 21, the suspension element 21 being intended to receive the balance 3 to fix the balance 3 on the flexible support 2. When it is fixed on the flexible support 2, the balance 3 is thus suspended from the base 20 by the flexible pivot, in this case by the elastic blades 2a, 2b.

[0038] The elastic blades 2a, 2b are preferably identical but extend in parallel planes and in different directions to cross without contact. In plan view from above, the crossing point of the blades 2a, 2b is preferably coincident with the geometric center of the balance 3 when the balance 3 is fixed on the suspension element 21. The crossing of the blades 2a, 2b defines a virtual axis of rotation A of the balance 3 relative to the base 20. The virtual axis of rotation A is preferably perpendicular to the plane of the balance

[0039] 3. The flexible pivot, in particular the first and second blades 2a, 2b, thus serves to suspend the balance 3 from the base 20, to guide the balance 3 in rotation relative to the base 20 around the virtual axis of rotation A and to exert on the balance 3 an elastic restoring torque tending to bring it back into an equilibrium position relative to the base 20 which corresponds to the rest position illustrated in Figures 1 and 2, in which the potential energy of the flexible pivot is zero.

[0040] The balance 3 comprises for example a circular rim 30 and at least two spokes, for example two spokes forming a diametrical arm 31, allowing for example the attachment of the balance 3 on the suspension element 21 of the flexible support 2. The rim 30 of the balance 3 carries for example weights 32 allowing the inertia to be adjusted, the rim 30 and the weights 32 preferably constituting the majority of the inertia mass of the balance 3. The balance 3, in particular the rim 30 and the weights 32, can be made of a dense material such as beryllium copper, gold, platinum, nickel silver or any other dense metal or alloy. It can thus have a small diameter for a given moment of inertia. In this way, friction with the air is reduced, which increases the quality factor.

[0041] According to the illustrated embodiment, the balance 3 comprises a continuous circular rim 30 forming a complete ring. Other embodiments of balances are conceivable within the scope of the invention. The balance may in particular comprise a discontinuous rim and / or a plurality of arms, the bulk of whose mass is preferably located at their distal end relative to the virtual axis of rotation. Preferably, the balance is symmetrical relative to the virtual axis of rotation and its center of gravity preferably coincides with the virtual axis of rotation when the balance is fixed to the flexible support.

[0042] The spokes of the balance 3, for example the two spokes forming the diametrical arm 31, are preferably configured so that when the balance 3 is fixed on the flexible support 2, a median plane of the felloe 30, perpendicular to the virtual axis of rotation A and passing through the middle of the height of the felloe 30, is essentially merged with a median plane of the flexible pivot, perpendicular to the virtual axis of rotation A and passing equidistant between the two elastic blades 2a, 2b. The spokes of the balance 3, for example the two spokes forming the diametrical arm 31, comprise for example around their part close to the virtual axis of rotation A a step in the direction of the virtual axis of rotation A to at least partially house the suspension element 21 there.

[0043] The spokes of the balance 3, for example the two spokes forming the diametrical arm 31, are for example fixed to the suspension element 21 using pins. The suspension element 21 is preferably in conformity with the diametrical arm 31, for example a suspension arm. Preferably, a lower arm 4 is fixed to the suspension element 21, on the side opposite that to which the diametrical arm 31 is fixed. The lower arm 4 is for example of the same material as the balance 3 and its mass is preferably determined so that the center of gravity of the oscillating member of the oscillator 1 is substantially on the median plane of the felloe 3, which preferably corresponds to the median plane of the oscillating member of the oscillator 1.

[0044] In the present description, the expression "oscillating member" designates the balance 3 with all the elements of the oscillator 1 which oscillate with the balance 3 when the oscillator 1 is in operating mode. The oscillating member thus comprises, for example, in the illustrated embodiment: the balance 3, the suspension element 21 and the lower arm 4. The radius of the oscillating member is defined as the distance between the virtual axis of rotation A and the part of the oscillating member furthest from the virtual axis of rotation A, for example, in the illustrated embodiments, the distance between the virtual axis of rotation A and the outer periphery of the rim 30 of the balance 3.The periphery of the oscillating member is defined by the extension of the arc of a circle traveled by the part of the oscillating member furthest from the virtual axis of rotation A when the oscillating member oscillates, typically by a circle of radius equal to the radius of the oscillating member and centered on the virtual axis of rotation A. In the embodiments illustrated, the periphery of the oscillating member corresponds for example to the outer periphery of the rim 30 of the balance 3.

[0045] Figure 2 represents the oscillator 1 of Figure 1 without the lower arm and without the pins in order to illustrate the housing of the suspension element 21 in the recess of the two spokes forming the diametrical arm 31 and the crossing of the blades 2a, 2b at the center of the balance 3 when the latter is fixed on the suspension element 21.

[0046] The flexible support 2 is for example manufactured monolithically, preferably by micro-etching, for example in silicon or any other suitable material, according to the deep reactive ion etching technique known as “DRIE” (Deep Reactive Ion Etching). The flexible support 2 is for example formed according to the two-level DRIE technique, making it possible to monolithically form the flexible support 2 with the two non-contact crossed blades 2a, 2b from a substrate composed of two layers of silicon bonded together by a layer of silicon oxide. The silicon parts, in particular the crossed blades 2a, 2b, may be coated with a reinforcing layer, for example a layer of silicon oxide, making it possible to improve their mechanical strength. Such a layer of silicon oxide may furthermore have a thickness chosen to make the frequency of the oscillator insensitive to a temperature variation, typically to a variation of 30°C.

[0047] Other manufacturing methods and / or materials are, however, conceivable within the scope of the invention for manufacturing the flexible support. For example, the flexible support may be formed by assembling two or more silicon parts manufactured using the DRIE technique at a single level, each part comprising an elastic blade and a portion of the base and the suspension element, a spacer made of a different material being, for example, inserted between the silicon parts at the base and / or the suspension element to ensure a certain gap between the elastic blades.

[0048] Referring to Figure 3, the clockwork mechanism of the invention comprises the oscillator 1 and a stopping device 6 for stopping the oscillator 1 and allowing it to be restarted.

[0049] According to the invention, the oscillating member of the oscillator comprises a radial element, that is to say an element extending radially with respect to the virtual axis of rotation A between the peripheral element(s) of the oscillating member, for example the felloe 30 of the balance 3, and a zone corresponding essentially to the virtual axis of rotation A. According to the embodiments illustrated by way of non-limiting example in the figures, the radial element of the oscillating member comprises for example the two spokes of the balance 3 forming the diametral arm 31, the suspension element 21 and the lower arm 4. Other embodiments are however possible within the scope of the invention. The radial element may for example comprise a single spoke, three or more spokes, a solid sector covering a part of the plate of the oscillating member, etc.According to the invention, the radial element comprises a stop element 5a allowing the stop device 6 to stop the oscillating member in a determined position at non-zero potential energy. The stop element 5a being part of the radial element of the oscillating member, this allows it to be distinguished from the element(s) constituting the bulk of the inertial mass of the oscillating member, for example the rim 30 and the weights 32, which are generally located at the periphery of the oscillating member, thus allowing decoupling of the functions of stopping and regulating the oscillation.

[0050] According to the embodiment illustrated in Figure 3, the stop element 5a is monolithic with the lower arm 4. The stop element is for example a first finger 5a extending from the virtual axis of rotation A, for example from the center of the lower arm 4, preferably radially, preferably in a direction perpendicular to the longitudinal axis of the lower arm 4.

[0051] The stop device 6 comprises a stop member 7, for example a stop lever articulated around a pivot 70 preferably fixed relative to the base 20. The stop lever 7 is preferably controlled by a control mechanism not shown linked for example to the winding stem of a timepiece and / or to a push button and / or to any other suitable control member. The end of the stop lever 7 preferably comprises a stop 71, for example a pin, intended to cooperate with the stop element 5a to block the oscillating member in a non-zero energy stop position such as that illustrated for example in FIG. 3. The stop position of the oscillating member preferably corresponds to an angular position relative to the base 20 close to the stationary amplitude of the oscillating member.The stop member 7 is movable, preferably by means of the control mechanism, between an active position in which the oscillator is stopped by the stop member 7 in the stop position and an inactive position in which the oscillator is released and the oscillating member can oscillate freely.

[0052] When the stop member 7 is in the inactive position, the stop 71 is placed outside the path taken by the stop element 5a during the oscillation of the oscillating member, so that the stop element 5a cannot come into contact with the stop 71 and the oscillating member can oscillate freely. When the stop member 7 is moved, for example pivoted, in a first direction towards the active position, the stop 71 is introduced into the path of the stop element 5a, i.e. into the sector covered by the stop element 5a during the oscillation of the oscillating member. Preferably, during the movement of the stop member 7 from the inactive position to the active position, the stop 71 travels through the sector covered by the stop element 5a from one end to the opposite end, preferably corresponding to the stop position.Thus, whatever the angular position of the oscillating member, and therefore of the stop element 5a, at the start of the movement of the stop member 7, the stop element 5a will come into contact against the stop 71 the oscillator 1 will be stopped. The position at which the stop element 5a comes into contact with the stop 71, and consequently the angular position of the oscillator 3 when it is stopped by the stop member 7, is not predetermined. If this angular position does not correspond to the stop position determined by the active position of the stop member 7, the stop 71 drives the stop element 5a in its movement to the active position of the stop member 7 thus rotating the oscillating member around the virtual axis of rotation A.The mechanism of the invention is configured so that the force exerted by the stop member 7 on the oscillating member, in particular the force exerted by the stop 71 on the stop element 5a, is always exerted essentially tangentially relative to the virtual axis of rotation A, thus avoiding any stress on the flexible pivot outside of its rotational movement, in particular avoiding any longitudinal stress, in tension or compression, on the elastic blades 2a, 2b. In the stop position, the flexible support 2 is out of its rest position, in a position with non-zero potential energy, that is to say in a position in which the elastic restoring force of the flexible pivot, for example of the elastic blades 2a, 2b, is non-zero.According to the invention, the stopping force exerted by the stop 71 on the stopping element 5a when the stopping member 7 is in the active position is oriented essentially tangentially relative to the virtual axis of rotation A and does not include a significant radial component which could cause tension or compression of the elastic blades 2a, 2b.

[0053] In the stop position, the non-zero potential energy is sufficient to allow the oscillator 1 to restart by itself, that is to say only following the removal of the stop 71 and the release of the oscillating member. The stop position of the oscillating member is preferably close to the angular position corresponding to its stationary amplitude, preferably substantially identical to its stationary amplitude. When the oscillator 1 restarts, when the stop member 7 is returned to its inactive position in a second direction opposite to the first direction, the oscillating member thus quickly, preferably immediately, resumes its stationary oscillation.

[0054] Preferably, the stop element 5a is located, in projection in a plane perpendicular to the virtual axis of rotation A, between the virtual axis of rotation A and the periphery of the oscillating member. Thus, the movements of the stop 71 between the active position and the inactive position are preferably confined, in projection in a plane perpendicular to the virtual axis of rotation A, inside the periphery of the oscillating member, thus limiting the size of the mechanism of the invention around the oscillating member.

[0055] More preferably, the stop element 5a is close to the virtual axis of rotation A, thus limiting the distance to be traveled by the stop 71 to be out of the path of the stop element 5a. The stop 5a can thus be quickly moved out of the path of the stop element 5a and preferably does not slow down the oscillator during its first oscillation after the removal of the stop 71. The resumption of the oscillation at its stationary amplitude is thus practically instantaneous and is not hindered by the removal of the stop member 7.

[0056] Preferably, the lower arm 4 comprises a second finger 5b to compensate for the imbalance introduced by the first finger 5a. The second finger 5b is preferably arranged symmetrically to the first finger 5a relative to the virtual axis of rotation A. Compensating for the imbalance contributes to the balance of the oscillating member around the virtual axis of rotation A and also makes it possible to limit any imbalances when the oscillator is stopped by the stop member 7 which could cause the oscillating member to tilt relative to the virtual axis of rotation A and generate torsional stresses on the flexible pivot 2.

[0057] The first finger 5a or the second finger 5b may further serve as an impulse element and cooperate with the escapement, for example a Swiss lever escapement, for maintaining the oscillations of the oscillator and regulating a watch movement comprising the mechanism of the invention. According to certain embodiments, the oscillating member comprises an impulse element integral with the oscillating member distinct from the first finger 5a and / or the second finger 5b, which is not illustrated in the figures.

[0058] According to another embodiment illustrated by Figure 4, the stop member 7 is a stop arm mounted to rotate around an axis preferably coincident with the virtual axis of rotation A of the oscillating member. The stop arm 7 comprises for example two stops 71, for example pins, arranged on either side of the axis of rotation, preferably at an equal distance from the latter. In the inactive position, the stop arm 7 is positioned around its axis of rotation so that the stops 71 are not located on the path of the first and second fingers 5a, 5b. To stop the oscillation of the oscillator 1, the stop arm 7 is pivoted around its axis by a control mechanism not shown in order to introduce the stops 71 on the path of the first and second fingers 5a, 5b.The stops 71 are thus moved in a first direction between the inactive position and the active position and pass through the sector covered by the corresponding stop element 5a; 5b, along an arc-shaped trajectory centered on the virtual axis of rotation A. Each finger 5a; 5b thus acts as a stop element for the oscillating member, each coming into contact with a pin 71 of the stop arm 7. In a manner similar to that explained above in relation to the embodiment illustrated in FIG. 3, the position at which each stop element 5a; 5b comes into contact with the corresponding stop 71, and consequently the angular position of the oscillator 3 when it is stopped by the stop member 7, is not predetermined.If this angular position does not correspond to the stop position determined by the active position of the stop member 7, the stops 71 drive the stop elements 5a; 5b in their movement to the active position of the stop member 7, thus rotating the oscillating member around the virtual axis of rotation A. The stop member 7 is pivoted to the active position in which the oscillating member is stopped in a determined stop position with non-zero energy illustrated in FIG. 4. In the stop position, the non-zero potential energy is sufficient to allow the oscillator 1 to restart by itself, that is to say only following the removal of the stops 71 and the release of the oscillating member.When the stop member 7 is in the active position corresponding to the stop position of the oscillating member, the angular position of the oscillating member relative to its rest position preferably corresponds essentially to its stationary amplitude. Thus, as explained above, when the oscillator 1 is restarted, when the stop member 7 is returned to its inactive position in a second direction opposite to the first direction, the oscillating member quickly, preferably immediately, resumes its stationary oscillation.

[0059] As explained above, the mechanism of the invention is configured so that the force exerted by the stop member 7 on the oscillating member, in particular the force exerted by the stops 71 on the stop elements 5a; 5b, is always exerted essentially tangentially relative to the virtual axis of rotation A, thus avoiding any stress on the flexible pivot outside of its rotational movement, in particular avoiding any longitudinal stress, in traction or compression, on the elastic blades 2a, 2b.

[0060] According to this embodiment, the stopping force exerted by the stopping member 7, in particular by the stops 71, on the oscillating member, in particular on the first and second fingers 5a, 5b, is distributed into two forces of equal intensity essentially tangential to the virtual axis of rotation A, but of opposite directions, thus maintaining the oscillating member in a stable position around its virtual axis of rotation A, thus minimizing the risks of tilting of the balance 3 relative to the virtual axis of rotation A.

[0061] According to another embodiment not shown, the stop arm movable in rotation around an axis coincident with the virtual rotation axis A comprises only one stop and interacts with only one stop element of the oscillator.

[0062] According to another embodiment of the oscillator 1 illustrated in Figures 5 to 7, the first and second fingers 5a, 5b are included in the flexible support 2 which is for example formed of three layers, each layer preferably comprising a part of the base 20 and a part of the suspension element 21. A first layer comprises for example the first elastic blade 2a, the second layer or intermediate layer preferably comprises the first and second fingers 5a, 5b, and the third layer comprises for example the second elastic blade 2b. As explained previously, the flexible support 2 is for example monolithic and manufactured using a multi-level etching method, for example by multi-level DRIE etching, or by the assembly of several single-layer elements.The flexible support 2 can also be manufactured by combining these methods, for example by manufacturing two layers monolithically and a third layer individually; the flexible support 2 is then formed by assembling these two elements.

[0063] As for the oscillator according to the embodiments illustrated in the figures

[0064] 1 to 4, the oscillator 1 according to the embodiment illustrated in figure 5 can be associated in a clockwork mechanism according to the invention with a stop member 7 in the form of a stop lever comprising a single stop 71 as illustrated in figure 6, or with a stop member 7 in the form of a stop arm comprising a single stop or two stops 71 arranged on either side of the axis of rotation of the arm, as illustrated in figure 7.

[0065] The advantage of the embodiments illustrated by Figures 5 to 7 is that the contact between the stop member 7 and the stop element(s) 5a, 5b is made at a height corresponding substantially to the height of the center of gravity of the oscillating member, thus further reducing the risks of tilting of the oscillating member when it is held in the stop position. It is important, however, to configure the stop member 7 and its movement between the active position and the inactive position so that the stop(s) 71 are not located in the path of the second elastic blade 2b during oscillation, the height of the second elastic blade 2b being located between the plane of the stop member 7 and the plane of the stop element(s) 5a; 5a, 5b.

[0066] According to the embodiments described above, the flexible pivot oscillator 1 comprises a flexible support 2 and a balance 3 fixed on the flexible support. However, it is conceivable within the scope of the invention to use an oscillator whose balance is manufactured integrally with the flexible support, for example by etching a monolithic oscillator, or by assembling single-layer elements, each single-layer element comprising a part of the balance and a part of the flexible support.

[0067] According to the embodiments illustrated above, the stop element(s) 5a; 5a, 5b are fingers extending radially close to the virtual axis of rotation A and the stop(s) 71 are pins cooperating with the finger(s) to stop the oscillator. Other embodiments of the stop element(s) and the stop(s) are, however, conceivable within the scope of the invention. For example, the stop element(s) of the oscillating member may be pins extending, for example, in the direction of the virtual axis of rotation A and the stop(s) may be stop surfaces, for example fingers of the stop member. According to other embodiments, the stop element(s) are, for example, teeth or any other element making it possible to block the oscillating member using a suitable stop. The stopping element(s) are, however, preferably as close as possible to the virtual axis of rotation of the flexible pivot oscillator.

Claims

Claims 1. Clock mechanism comprising an oscillator (1) with flexible pivot, and a stopping device (6) for stopping the oscillator (1), the oscillator (1) comprising: - a base (20) for fixing the oscillator (1) to a fixed or mobile frame of a watch movement; - an oscillating member (3, 21, 4) intended to oscillate in rotation about a virtual axis of rotation (A), the oscillating member (3, 21, 4) comprising a radial element (31, 21, 4) relative to the virtual axis of rotation (A), the radial element (31, 21, 4) comprising at least one stop element (5a; 5a, 5b); and - a flexible pivot (2a, 2b) for suspending the oscillating member (3, 21, 4) from the base (20) and defining the virtual axis of rotation (A); the stopping device (6) comprising: - a stop member (7) with at least one stop (71); the stop member (7) being configured to be movable between an active position in which the at least one stop (71) cooperates with the at least one stop element (5a; 5a, 5b) to block the oscillating member (3, 21, 4) in a predetermined position in which the elastic return force of the flexible pivot (2a, 2b) is non-zero, and an inactive position in which the at least one stop (71) is spaced from the path taken by the at least one stop element (5a; 5a, 5b) during the oscillation of the oscillating member (3, 21, 4), the stop member (7) being configured so that during the movement in a first direction of the stop member (7) from the inactive position to the active position, the at least one stop (71) follows a circular path centered around an axis parallel to the axis of rotation virtual (A), the at least one stop (71) and the at least one stop element (5a;5a, 5b) being configured so that when the at least one stop (71) cooperates with the at least one stop element (5a; 5a, 5b) to block; the oscillating member (3, 21, 4), the force exerted by the at least one stop (71) on the at least one stop element (5a; 5a, 5b) is essentially tangential to the rotational movement performed by the at least one stop element (5a; 5a, 5b) during the oscillation of the oscillating member (3, 21, 4), the stop member (7) being further configured to be returned from the active position to the inactive position in a second direction opposite to the first direction.

2. Clock mechanism according to the preceding claim, in which the at least one stop element (5a; 5a, 5b) is located, in projection in a plane perpendicular to the virtual axis of rotation (A), between the virtual axis of rotation (A) and the periphery of the oscillating member (3, 21, 4).

3. Clock mechanism according to one of the preceding claims, in which the at least one stop element (5a; 5a, 5b) extends radially relative to the virtual axis of rotation (A), perpendicular to the radial element (31, 21, 4).

4. Clockwork mechanism according to the preceding claim, in which the at least one stop element (5a) is a first finger and the radial element (31, 21, 4) comprises a second finger (5b) extending radially relative to the virtual axis of rotation (A) in a direction opposite to the direction of the first finger (5a) to compensate for the unbalance of the oscillating member (3, 21, 4) induced by the first finger (5a), the second finger (5b) being located, in projection in a plane perpendicular to the virtual axis of rotation (A), between the virtual axis of rotation (A) and the periphery of the oscillating member (3, 21, 4).

5. Clock mechanism according to the preceding claim, in which the at least one stop (71) is a pin.

6. Clock mechanism according to the preceding claim, in which the stop member (7) is a lever and the pin (71) is arranged at one end of the lever (7).

7. Clock mechanism according to one of claims 1 to 5, the stop member (7) comprising two stops (71), and the radial element (31, 21, 4) comprising two stop elements (5a, 5b) each extending radially relative to the virtual axis of rotation (A) and in opposite directions, each stop (71) cooperating with one of the two stop elements (5a; 5b) when the stop member (7) is in the active position.

8. Clockwork mechanism according to the preceding claim, in which the stop member (7) is a stop arm mounted to rotate around an axis of rotation preferably coincident with the virtual axis of rotation (A) of the oscillating member (3, 21, 4), the two stops (71) being arranged on either side of the axis of rotation, preferably at an equal distance from the axis of rotation.

9. Clock mechanism according to one of the preceding claims, in which the at least one stop element (5a; 5a, 5b) extends in a plane perpendicular to the virtual axis of rotation (A) and passing essentially through a center of gravity of the oscillating member (3, 21, 4).

10. Clock mechanism according to one of the preceding claims, in which the flexible pivot (2a, 2b) comprises two elastic blades crossed without contact.

11. Clock mechanism according to one of the preceding claims, in which the base (20) and the flexible pivot (2a, 2b) are manufactured by etching a silicon-based substrate.

12. Clock mechanism according to the preceding claim, in which the base (20) and the flexible pivot (2a, 2b) are manufactured monolithically.

13. Watch movement comprising a watch mechanism according to one of the preceding claims and a control mechanism for controlling the stop device (6).

14. Watch movement according to the preceding claim, the watch movement being a chronograph movement.

15. Timepiece comprising a watch movement according to one of claims 13 and 14.

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