Escapement mechanism with bistable leaf spring

Abstract

The present invention relates to an escapement mechanism (1) arranged to supply mechanical impulses from a driving source to an oscillating regulator (2) of a clock movement via a leaf spring (6) operating in buckling around an inflection point (I). The mechanism comprises a winding rocker (10), a release rocker (12), and a locking rocker (14). The leaf spring (6), in normal operation, is capable of accumulating energy from the driving source transmitted by winding elements (40a, 40b) during a winding phase, remaining in a wound state during a locking phase, and then releasing the accumulated energy to the oscillating regulator (2) during a pulse phase preceded by a release phase. The locking rocker (14) comprises two locking arms (56a, 56b), each equipped with a locking member. (58a, 58b) arranged to cooperate with a locking member (46a,46b) respective complement of the cocking lever (10) to block said cocking lever (10) during the locking phase. Each locking arm (56a, 56b) of said locking rocker (14) has, at its free end, an inclined plane (66a, 66b) configured to cooperate with the starting inclined plane (61a, 61b) provided correspondingly on the arming rocker (10) during a self-start phase during which an activation of the drive source causes the arming rocker (10) to move, the free passage of which is permitted by the locking rocker (14) which was previously positioned by the detent rocker (12) under the influence of the oscillating regulator (2) at rest, said angular movement of the arming rocker causing a displacement of the locking rocker (14) by pushing one of the starting inclined planes (61a, 61b) on the corresponding inclined plane (66a, 66b) of the locking rocker (10),so that said locking lever (14) rotates the oscillating regulator (2) out of the lifting angle, the escapement mechanism (1) positioning itself in a position corresponding to a locking phase ready to be followed by an unlocking phase and a pulse phase of normal operation.

Description

Technical field

[0001] The present invention relates to the field of mechanical watchmaking. It relates, more particularly, to an escapement mechanism arranged to provide mechanical impulses from a driving source to an oscillating regulator of a watch movement by means of a leaf spring working in buckling around an inflection point in cooperation with a winding lever, a detent lever and a locking lever.

[0002] The present invention also relates to a watch movement comprising such an escapement mechanism, as well as a timepiece comprising such an escapement mechanism or such a movement. State of the art

[0003] In the field of watchmaking, an escapement mechanism is well known which is arranged to supply pulses of mechanical energy from a driving source to an oscillating regulator of a watch movement by means of a leaf spring working in buckling around an inflection point. One example of this is the Applicant's patent EP 2105806.

[0004] Such an escapement mechanism makes it possible, in particular, to maintain the oscillations of the balance wheel constantly throughout the power reserve, regardless of the energy source.

[0005] Various improvements have been made to this escapement mechanism to improve its efficiency and operational reliability, such as those described in documents CH 710925, WO 2018 / 015146, EP 3599514 or EP 3623875 also in the name of the Applicant.

[0006] A first improvement described in patent CH 710925 or CH 710685 consisted of adding a locking lever which prevents accidental unlocking between the locking pallets of the winding lever and the lugs of the teeth of the winding wheels. A second development described in patent EP 3623875 consisted of changing the function of this locking lever so that it becomes an element for locking and releasing the escapement. The winding lever pushed by the escapement wheels is blocked by the locking lever, the latter being controlled by the balance via the detent lever and its jewel. The functions of the escapement are thus better sequenced and secured, rebounds are eliminated and the energy supplied by the escapement spring goes directly to the balance because the escapement spring no longer participates in unlocking the escapement. Efficiency is improved.

[0007] However, the resulting escapement mechanisms have the disadvantage of not being able to self-start when the driving source is wound or following a shock that has severely slowed the balance spring. The torque provided by the escapement spring is then not sufficient to drive the balance, which is then stopped, out of the lift angle to allow it to start moving, that is to say out of the angle during which the roller pin is in contact with the fork inlet. This condition allows the escapement organs to position themselves so that the escapement can lock in such a way as to be able to accumulate the energy of the leaf spring during a rest phase and to restore it during the impulse triggered by the release made by the balance. These conditions are not met because the only connection between the escapement spring and the balance spring is the elasticity of the escapement spring.There is no element to position the components to ensure a configuration that allows the movement to self-start. Once these conditions are met, the torque of the balance spring is also not sufficient to overcome the rest of the wound escapement, that is to say the rest of the winding lever on the locking lever and to release the driving train. The escapement will therefore remain "hanging" in a position where the escape spring has been wound by the driving train and where the winding lever will be in abutment against the rests of the locking lever.

[0008] The present invention aims to overcome these drawbacks by proposing an escapement mechanism capable of self-starting arranged to provide mechanical impulses from a driving source to an oscillating regulator of a watch movement by means of a leaf spring working in buckling around an inflection point. Disclosure of the invention

[0009] To this end, the invention relates to an escapement mechanism arranged to supply pulses of mechanical energy from a driving source to an oscillating regulator of a watch movement by means of a leaf spring working in buckling around an inflection point, said mechanism comprising a winding lever, a detent lever and a locking lever of the winding lever arranged in kinematic connection with the detent lever, said leaf spring being capable, in normal operation, by means of said winding lever, said locking lever and said detent lever, of accumulating the energy from the driving source transmitted by winding wheels during a winding phase, of then remaining in a wound state during a locking phase, then of restoring the accumulated energy to said oscillating regulator during an impulse phase preceded by an unlocking phase,said locking lever comprising two locking arms each provided with a locking member arranged to cooperate with a respective complementary locking member of the arming lever to block said arming lever during the locking phase.,

[0010] According to the invention, each locking arm of said locking lever comprises, at its free end, at least one inclined plane configured to cooperate with a starting inclined plane provided in correspondence on the winding lever during a self-start phase during which an activation of the driving source causes an angular movement of the winding lever, the free passage of which is allowed by the locking lever until then positioned by the detent lever under the influence of the oscillating regulator at a standstill, said angular movement of the winding lever causing a displacement of the locking lever by pushing one of the starting inclined planes of the winding lever onto the corresponding inclined plane of the locking lever, so that said locking lever, via the detent lever, rotates the oscillating regulator out of the lifting angle,the escapement mechanism being positioned in a position corresponding to a locking phase ready to be followed by an unlocking phase and an impulse phase of normal operation.,

[0011] Advantageously, the inclined planes of the locking lever and the starting inclined planes of the winding lever are configured so that, during the self-start phase, the winding lever, set in motion by the action of the winding mobiles themselves driven by the driving source, positions the locking lever, via their respective inclined planes, the detent lever and the oscillating regulator in such a way that the winding lever is free to move until the end of being driven by one of the winding mobiles and the latter falls.

[0012] Thus, the detent lever is moved to force the oscillating regulator to start moving and therefore to leave the lift angle. This is possible because the oscillating regulator is close to the center line when the movement is stopped. In this configuration, the position of the locking lever does not allow the winding lever to stop on the locking member of the locking lever and allows the winding lever driven by the energy of the driving source to move to the end of being driven by one of the winding wheels until it falls. At this moment the locking lever forces the oscillating regulator into a position outside the lift angle.The escapement train can then turn and rewind the leaf spring in the other direction, but this time the winding lever, driven by the energy of the driving source, is free to move and will lock against the locking member of the locking lever in a position corresponding to a locking phase ready to be followed by an unlocking phase and an impulse phase of normal operation. The system is then ready to be released by the oscillating regulator, which returns to the center line and receives an impulse from the leaf spring. The movement starts.

[0013] The present invention also relates to a watch movement comprising an escapement mechanism as defined above.

[0014] The present invention also relates to a timepiece comprising an escapement mechanism or a watch movement as defined above. Brief description of the drawings

[0015] Other characteristics and advantages of the present invention will appear on reading the following detailed description of an embodiment of the invention, given by way of non-limiting example, and made with reference to the appended drawings in which: there figure 1 is an isometric view of an escapement mechanism of the invention, the leaf spring not yet bent; the figure 2 is an isometric view of the unbent leaf spring, its frame and the trigger lever; figure 3 is an isometric view of the winding lever used in the escapement mechanism of the invention, and the Figure 3a is a detailed view of the central portion of the arming lever; the figure 4 is an isometric view of the locking lever used in the escapement mechanism of the invention; the Figure 5 is a top view of the end of a locking arm of the locking toggle; figures 6 and 7 are isometric views of the winding wheels used in the escapement mechanism of the invention; the figures 8 to 20 represent different positions of the escapement mechanism of the invention during normal operation; and the figures 21 to 35 represent different positions of the escapement mechanism of the invention during a self-start phase. Embodiments of the invention

[0016] In reference to the figure 1, there is shown an escapement mechanism 1 according to the invention in a preferred embodiment. This mechanism, in a known manner described for example in patent EP 2105806, makes it possible to maintain the oscillations of an oscillating regulator 2, composed for example of a balance 2a associated with a balance spring 2b, by delivering to it energy received from a driving source, such as a barrel for example (not shown), via a terminal mobile 4 of the finishing train, such as a fifth wheel, by means of a bistable leaf spring 6 working in buckling around a central inflection point I, and the ends of which are integral with a frame 8 for fixing on a watch movement frame. The leaf spring 6 is formed of an initially straight elastic leaf, for example a silicon leaf. It is put into buckling during assembly so that it occupies a stable position corresponding to a first mode buckling.

[0017] The blade spring 6 cooperates with a winding lever 10, a detent lever 12 and a locking lever 14 of the winding lever 10 arranged in kinematic connection with the detent lever 12 in order to accumulate the energy from the driving source during winding phases, to then remain in a wound state during locking phases and to restore the accumulated energy to said oscillating regulator 2 during impulse phases preceded by unlocking phases, during normal operation of the watch movement.

[0018] With particular reference to the figure 2, the detent lever 12 is rigidly connected to the leaf spring 6 substantially at its central inflection point I and thus pivots around this inflection point I. It comprises, at one end, a detent fork 16 intended to cooperate with a double plate 20, 21 of the balance 2a, and more particularly with a plate pin 22 driven onto the large plate 20 of the double plate. A pin 18 is also provided intended to prevent any overturning as in a lever escapement. Thus, during normal operation of the watch movement, the detent lever 12 only starts moving around the inflection point I under the action of the plate pin 22 engaged in its detent fork 16 during the alternations of the balance 2a, thus transmitting to the latter the elastic energy accumulated during the winding phase of the leaf spring 6.

[0019] The movements of the trigger lever 12 are limited by stops in the form of stopcocks 8a, 8b, for example, advantageously integrated in monolithic form into the frame 8.

[0020] The trigger lever 12 comprises at the end opposite its trigger fork 16, an unlocking pin 24 secured to said trigger lever, said unlocking pin 24 cooperating with a connecting fork 26 of the locking lever 14 which will be described in detail below.

[0021] With particular reference to the figure 3, the arming lever 10 comprises a central portion 28 and two arming arms 30, 32 respectively comprising a first portion 30a, 32a and a second portion 30b, 32b. The first portions 30a, 32a extend symmetrically from the central portion 28. Their ends secured to the second portion 30b, 32b are kinematically linked to the leaf spring 6, in particular in the example shown by arming tenons 34a, 34b inserted with sufficient play in eyelets 6a, 6b of the leaf spring 6. The arming lever 10 is rotatable about an axis passing through the inflection point I. The arming lever 10 and the trigger lever 12 therefore pivot about the same axis perpendicular to the plane of the figure 1 passing through the inflection point I. However, the trigger lever 12 pivots coaxially with the arming lever 10 but independently.

[0022] The second portions 30b, 32b of the arming arms 30, 32 have at their free end an arming beak 36a, 36b respectively, intended to cooperate with an arming star 38a, 38b of an arming mobile 40a, 40b respectively.

[0023] With particular reference to figures 6 and 7 , the two left and right winding mobiles 40a, 40b also each comprise an escapement pinion 42a, 42b, coaxial and integral with the winding star 38a, 38b respectively and intended to mesh with the mobile 4 of the finishing gear train to pivot simultaneously in a synchronized manner in the same direction around separate axes of rotation. Each winding mobile 40a, 40b also comprises an inertia wheel 44a, 44b coaxial and integral with the winding star 38a, 38b and the escapement pinion 42a, 42b.

[0024] The second portions 30b, 32b of the arming arms 30, 32 are not symmetrical and are configured so that the arming beak 36a, i.e. the left arming beak, is directed towards the central portion 28 of the arming lever 10 while being the furthest from the axis of rotation of the arming lever 10 which passes through the inflection point I. The arming beak 36b, i.e. the right arming beak, is directed away from the arming lever 10 while being the closest to the axis of rotation of the arming lever 10.

[0025] The indexing of the winding mobiles 40a, 40b is such that when one of the winding beaks 36a, 36b is in contact with one of the winding stars 38a, 38b, the other winding beak 36a, 36b is not in contact with the other winding star 38a, 38b. Different safety and security features are provided by those skilled in the art for this purpose. For example, at the end of driving of a tooth of the winding star 38a, 38b on the corresponding winding beak 36a, 36b, a safety drop must occur before the other tooth of the winding star 38a, 38b comes into contact with the corresponding winding beak 36a, 36b.

[0026] Thus, when the winding star 38a of the winding wheel set 40a drives the winding beak 36a of the winding arm 30 to pivot the winding lever 10 in one direction (here clockwise) to wind the leaf spring 6, the winding wheel set 40b is devoid of contact with the winding beak 36b of the winding arm 32. Conversely, when the winding star 38b of the winding wheel set 40b drives the winding beak 36b of the winding arm 32b to pivot the winding lever 10 in the other direction (here counterclockwise) to wind the leaf spring 6, the escapement wheel set 40a is devoid of contact with the winding beak 36a of the winding arm 30.

[0027] The central portion 28 of the arming lever 10 comprises at its end opposite its center of rotation I, or tail, two resting beaks 46a, 46b, or projections, symmetrical to each other with respect to a median axis of said central portion 28, and intended to cooperate with the locking lever 14 as described in detail below. Each resting beak 46a, 46b is obtained by the intersection of the curved edge of the tail of the central portion 28 with an upper inclined plane 61a, 61b forming an acute angle with the edge of the curve. Said inclined planes 61a, 61b constitute the starting inclined planes whose role will be explained below.

[0028] The mechanism 1 according to the invention further comprises a locking lever 14 of the winding lever 10, shown more particularly in the figure 4This locking lever 14 is intended to operate the locking of the winding lever 10 when the leaf spring is wound in a metastable state as close as possible to its unstable state. The locking lever 14 is integral with an axis 48 pivotally mounted on the frame of the watch movement and is arranged in kinematic connection with the detent lever 12. In the embodiment shown, it comprises a rod 50 extending from a central body 52 traversed by the axis 48 along a longitudinal axis, said rod 50 being provided, at a first end, with the connecting fork 26 to said detent lever 12 via the unlocking pin 24. For this purpose, the fork 26 of the locking lever 14 comprises two horns 26a, 26b delimiting an inter-horn space 54 into which said unlocking pin 24 of the detent lever 12 is inserted.

[0029] At its second end opposite the connecting fork 26, the locking lever 14 also comprises two locking arms 56a, 56b extending symmetrically from one another relative to the longitudinal axis of the rod 50 from the central body 52. ​​These locking arms 56a, 56b are concentric with the pivot axis 48 of the locking lever 14 so that there is no pull between the winding lever 10 and the locking lever 14. Sufficient pull is already ensured by the leaf spring 6 of the escapement.

[0030] The two locking arms 56a, 56b are each provided with a locking member arranged to cooperate with a respective complementary locking member of the arming lever 10 in order to block said arming lever 10 during the locking phase.

[0031] Advantageously, the locking member is constituted by a resting beak 58a, 58b respectively of the locking lever 14, and the complementary locking member of the arming lever 10 is constituted by the resting beak 46a, 46b respectively described above.

[0032] This means that during a normal operating locking phase, either the right winding star 38b is in abutment on the right winding beak 36b of the winding lever 10 while the left locking beak 46a of the winding lever 10 is in abutment against the left locking beak 58a of the locking lever 14, or the left winding star 38a is in abutment on the left winding beak 36a of the winding lever 10 while the right locking beak 46b of the winding lever 10 is in abutment against the right locking beak 58b of the locking lever 14, so that all the components of the escapement are stationary, only the balance 2a freely completing its oscillation.

[0033] According to the invention, each locking arm 56a, 56b of the locking lever 14 comprises at its free end, following the locking member constituted by the resting beak 58a, 58b respectively, at least one inclined plane 66a, 66b shown in the Figures 4 and 5 , configured to create a contact surface and cooperate with a starting inclined plane 61a, 61b (shown in the Figure 3a) provided in correspondence on the winding lever 10 during a self-start phase during which an activation of the driving source causes an angular movement of said winding lever 10 which, by becoming driving on the locking lever 14, causes a movement of said locking lever 14 which pivots along its axis 48 by the thrust of one of the inclined starting planes 61a, 61b of the winding lever 10 in movement on the inclined plane 66a, 66b of the locking lever 14 which is located opposite the corresponding inclined starting plane 61a, 61b, here the straight inclined planes 66b and the inclined starting plane 61b, so that said locking lever 14,which in turn becomes a driving force on the oscillating regulator 2 by means of the detent rocker 12 whose unlocking pin 24 works with the fork 26 of the locking rocker 14 and whose detent fork 16 drives the plate pin 22, rotates said oscillating regulator 2 out of the lifting angle (i.e. the angle during which the plate pin 22 is in contact with the inlet of the fork 16). In parallel, the escapement mechanism 1 is positioned in a position corresponding to a locking phase ready to be followed by an unlocking phase and an impulse phase of normal operation.,

[0034] Preferably, the inclined planes 66a, 66b of the locking lever 14 are of complementary shape to the corresponding starting inclined planes 61a, 61b of the arming lever 10.

[0035] Advantageously, each locking arm 56a, 56b of the locking lever 14 successively comprises, in the direction of its free end, a first segment, which forms the resting beak 58a, 58b respectively constituting the locking member of the locking lever, and a second segment 62a, 62b, said first and second segments 58a, 62a or 58b, 62b being connected in particular by the respective inclined planes 60a, 60b.

[0036] More specifically, and in relation to the Figure 5 , the first segment is of substantially circular shape concentric with the pivot axis 48 of the locking lever 14. It has on its inner face opposite the rod 50 a surface concentric with the pivot axis 48 which constitutes the rest face of the rest beak 58a, 58b.

[0037] The second segment 62a, 62b has a thickness e' less than the thickness e of the first segment 58a, 58b. The second segment 62a, 62b has on its inner face facing the rod 50 a surface concentric with the pivot axis 48 and with the first segment 58a, 58b and further from the rod 50 than the concentric surface of the first segment 58a, 58b.

[0038] Said first and second segments 58a, 62a or 58b, 62b are connected by: inclined planes 60a, 60b comprising a first inclined plane 64 arranged to form a chamfer for the complementary locking member of the winding lever, i.e. the resting beak 46a, 46b, and a second inclined plane 66a, 66b forming an obtuse angle with the surface concentric with the pivot axis 48 of the first segment 58a, 58b, chosen so that the contact of the starting inclined plane 61a, 61b of the winding lever 10 in angular movement with said second inclined plane 66a, 66b causes a rotation of the locking lever 14 along the pivot axis 48, the inclined planes 66a, 66b of the locking lever 14 preferably being of a shape complementary to the corresponding starting inclined planes 61a, 61b, and a step 68 configured to allow the complementary locking member (i.e. the resting beak 46a, 46b) of the arming lever 10 to be able to engage therein in order to allow said arming lever 10 to complete its travel.

[0039] In a particularly advantageous manner, the inclined planes, here the straight inclined plane 66b, of the locking lever 14 are configured so that, during the self-starting phase, the winding lever 10 (whose angular movement has allowed the leaf spring 6 to accumulate the energy from the driving source and to position, via the detent lever 12, the locking lever 14 so that the starting inclined plane, here 61b, of the winding lever 10 in angular movement can push on the inclined plane 66b of the locking lever 14 opposite), positions the locking lever 14, the detent lever 12 and the oscillating regulator 2 so that the winding lever 10, driven by the energy from the driving source, is free to move until the end of being driven by one of the winding mobiles 40a, 40b, here the arming mobile 40a, and its fall.

[0040] Furthermore, in a particularly advantageous manner, the inclined planes 66a, 66b of the locking lever 14 are configured to push on the corresponding starting inclined planes 61a, 61b of the winding lever 10 in order to move said winding lever 10 away from the locking members (i.e. the resting beak 58a, 58b) of the locking lever 14 when the driving energy becomes insufficient to drive the winding lever 10. Indeed, when the driving energy becomes insufficient, the balance 2a will still perform a few alternations and drive the locking lever 14 with it but also the leaf spring 6 which will impose a position on the winding lever 10. The inclined planes 66a, 66b of the locking lever 14 will become a motor on the winding lever 10 by gently moving it away.Without these inclined planes 66a, 66b, the locking lever 14, under the action of the kinetic energy of the moving balance 2a, would lock abruptly on the winding lever 10, which could damage the locking lever 14 or its fork 26, the winding lever 10, the detent lever 12 or the roller pin 22. Thus, thanks to the inclined planes 66a, 66b, the locking lever 14 does not lock on the resting beaks 46a, 46b of the winding lever 10 when the latter is no longer under the influence of the driving force of the winding stars 38a, 38b at the end of the power reserve.

[0041] According to another aspect of the invention, each locking arm 56a, 56b comprises, on the surface of the second segment 62a, 62b concentric with the pivot axis 48, a groove 70a, 70b extending perpendicular to the upper and lower faces of the locking arm 56a, 56b and arranged to constitute a capillary point for a lubricant. The portion of the second segment 62a, 62b between the recess 68 and the groove 70a, 70b respectively advantageously constitutes a clamp 71a, 71b for the resting beaks 46a, 46b of the arming lever 10 in order to prevent excessive angular displacement of said arming lever 10. Grooves 72a, 72b constituting a capillarity point for a lubricant are also provided at the top of the arm portions constituting the resting beaks 58a, 58b.

[0042] The clamps 71a, 71b are a safety stop to prevent excessive angular movement of the winding lever 10, this during a phase where said winding lever 10 is free, that is to say between the end of driving by one winding star 38a, 38b, and the start of driving by the other star 38a, 38b, and at the moment when the leaf spring 6 is in its natural buckling position.

[0043] The clamps 71a, 71b also allow the winding lever 10 to always be able to remain in an angular position which allows the winding stars 38a, 38b, of the winding mobiles 40a, 40b, to come into contact with the winding beaks 36a, 36b of the winding lever 10.

[0044] The stops 71a, 71b limit excessive angular displacement of the winding lever 10, which allows the inclined planes 66a, 66b of the locking lever 14 to still be able to drive the winding lever 10 in the event of an impact or starting. Without this stop, during an impact, the winding tenons 34a, 34b of the winding lever 10 could butt strongly against the inside of the eyelets 6a, 6b of the leaf spring 6 and force it further than its natural buckling position.

[0045] According to another aspect of the invention, the rod 50 of the locking lever 14 has a length (along its longitudinal axis) taken between its pivot center passing through the pivot axis 48 and the functional part of the inter-horn space 54 which is greater than or equal to twice the length of the detent lever 12 taken between its inflection point I and the unlocking pin 24. In other words, the point of contact between the locking lever 14 and the detent lever 12 is in a proportion 2 / 3 -1 / 3 of the total center distance (distance between the pivot center of the locking lever 14 and the inflection point I of the detent lever 12). In the escapement mechanisms of the prior art, the length of the rod of the locking lever 14 is less than half the length of the detent lever 12.

[0046] Increasing the length of the rod 50 of the locking lever and therefore shortening the location of the unlocking pin 24 on the trigger lever 12, allows for a longer lever arm which has two effects: reduction of the angle traveled by the locking lever, and therefore reduction of the torque required by balance 2a to overcome the release of the escapement, this reduces losses and increases the amplitude of the balance increase of the angle traveled by balance 2a when the locking lever is driving during the self-start phase.

[0047] The normal operation of the escapement mechanism 1 according to the invention is explained below with reference to figures 8 to 20 .

[0048] There figure 8represents the escapement mechanism 14 according to the invention after an impulse phase. The balance 2a having already received an impulse oscillates freely along its ascending supplementary arc. The leaf spring 6 is buckled in its first-order stable state, and is at rest unwound. The winding lever 10 is positioned so that the right winding star 38b of the right winding wheel set 40b is at the start of the drive of the right winding beak 36b of the winding lever 10. The left winding beak 36a of the winding lever 10 has released the tooth of the left winding star 38a of the left winding wheel set 40a.

[0049] This is followed by a winding phase of the winding lever 10 by the right winding star 38b, the energy being transmitted from the driving source to the wheel set 4 which rotates counterclockwise, driving the two winding wheels 40a, 40b simultaneously in the clockwise direction via their escapement pinion 42a, 42b. Only the right winding wheel set 40b can transmit the energy to the winding lever 10 via the right winding star 38b and the right winding beak 36b, creating a driving torque so as to pivot the winding lever 10 counterclockwise. The winding lever 10 then pivots around its axis I, winding the buckled leaf spring 6 by means of the winding tenons 34a, 34b inserted into the eyelets 6a, 6b of the leaf spring 6. The trigger lever 12 bears against the clamp 8a. The balance 2a being in its additional arc, the plate pin 22 is outside the entry of the trigger fork 16 of the trigger lever.Under these conditions, the winding of the leaf spring 6 will press the trigger lever 12 against the clamp 8a.

[0050] In reference to the figure 9 , at the end of the arming phase, the leaf spring 6 has deformed to pass from a first-order buckling to a buckling close to the second order, being armed in a metastable state, as close as possible to its unstable state. The right arming star 38b is in abutment on the right arming beak 36b of the arming lever 10 and the left rest beak 46a of the arming lever 10 is locked in abutment against the left rest beak 58a of the left locking arm 56a of the locking lever 14, as shown in the detail at figure 10on which the terminal wheel 4, here the fifth wheel, is not shown. The escapement mechanism 1 is then in its locking phase in which all the components of the escapement are immobile. Only the balance 2a freely completes its oscillation along its additional arc, the plate pin 22 being close to its entry into contact with the detent fork 16 of the detent lever 12.

[0051] Then come the unlocking and impulse phases with reference to the figure 11 and to the figure 12 on which the mobile terminal 4 is not shown.

[0052] The plate pin 22 of the balance 2a coming from its descending supplementary arc has entered the detent fork 16 of the detent lever 12 causing a rotation of the latter so that the detent lever 12 comes off the clamp 8a. This movement of the detent lever 12 forces the displacement of the leaf spring 6 beyond its metastable state. The instantaneous movement of the leaf spring 6, with its eyelets 6a, 6b, from its metastable state to a second-order buckled state causes the rotation of the detent lever 12 around the inflection point I in the counterclockwise direction. Said detent lever 12 becomes driving and will drive with it the plate pin 22 to begin transmitting the impulse to the balance 2a. During this time, the gear train is still stopped because the left resting beak 46a of the winding lever 10 is still in contact with the left resting beak 58a of the locking lever 14, as shown in the detail at figure 12 .

[0053] In the middle of the impulse phase shown in the figure 13 , the leaf spring 6 is supplying its impulse to the balance 2a via the fork of the detent lever 12. Said detent lever 12 rotating counterclockwise around the inflection point I, drives on the one hand the balance 2a in the clockwise direction by its fork and the plate pin 22, and on the other hand the locking lever 14 around its axis 48 in the clockwise direction via the unlocking pin 24 inserted in the fork 26 of the locking lever 14. Consequently, as shown in the detail at figure 14on which the terminal mobile 4 is not shown, the left resting beak 58a of the locking lever 14 has moved and released the left resting beak 46a of the winding lever 14. Said winding lever 14 no longer retains the driving force of the gear train because it is free. The gear train is therefore released but does not yet turn because the inertia of the wheels 44a, 44b prevents it from doing so.

[0054] At the end of the impulse phase shown in the figure 15, under the influence of the leaf spring 6, the trigger lever 12 has moved counterclockwise until it comes to bear against the clamp 8b, carrying with it the balance 2a via the trigger fork 16 and the plate pin 22. The locking lever 14 under the influence of the trigger lever 12 via the unlocking pin 24 inserted in the fork 26 of the locking lever 14 has also moved clockwise, moving away from the left resting beak 46a of the winding lever 10, as shown in the detail at figure 16on which the terminal mobile 4 is not shown. The locking lever 14 has released the winding lever 10, which then unlocked, no longer offers any resistance, the winding tenons 34a, 34b of the winding lever 10 no longer being in contact with the eyelets 6a, 6b of the leaf spring 6 following the passage of said leaf spring 6 into its stable state of the first order inverse to that of the figure 8 The cog having overcome the inertia preventing it from turning during the impulse can begin to turn, the mobile 4 being able to resume its rotation in the counterclockwise direction.

[0055] In reference to the figure 17, the balance wheel 2a continues its oscillation along its additional ascending arc. The released gear train has started to rotate, driven by the wheel set 4 which rotates counterclockwise, simultaneously driving the winding wheels 40a, 40b in the clockwise direction. The winding star 38b pushes the right winding beak 36b of the winding lever 10 until it reaches point on point, as shown in the detail at figure 18 . The winding lever 10 then rotates counterclockwise, without winding the leaf spring 6, its winding tenons 34a, 34b no longer being in contact with the eyelets 6a, 6b of the leaf spring 6. The left resting beak 46a of the winding lever 10 approaches the left clamp 71a of the left locking arm 56a of the locking lever 14 without touching it thanks to an operating safety device provided for this purpose, and is housed in the recess 68 under the inclined planes 60a, as shown in the detail at figure 18on which the mobile terminal 4 is not shown.

[0056] Then, in reference to the figure 19 , the balance 2a continues its oscillation along its additional ascending arc. The winding mobiles 40a, 40b continue their rotation in the clockwise direction so that the right winding star 38b leaves the right winding beak 36b of the winding lever 10. As a result, the gear train drops and the left winding star 38a comes into contact with the left winding beak 36a of the winding lever 10, as shown in the detail at figure 20 on which the terminal mobile 4 is not shown. The cycle driven by the right winding star 38b is finished. From this moment, a new cycle will resume as described above, but in the opposite direction being driven by the left winding star 38a, so that the winding lever 10 will wind the leaf spring 6 by moving clockwise.

[0057] During a stop phase, when the watch movement has stopped at the end of its power reserve due to a lack of driving force, the components of the escapement mechanism of the invention behave as follows: the leaf spring 6 is in its natural bent position at rest, unarmed, as shown in the figures 8 Or 19 ; the winding lever 10 by means of the winding tenons 34a, 34b which are located inside the eyelets 6a, 6b is in a position imposed by the leaf spring 6. The winding stars 38a, 38b of the winding mobiles 40a, 40b are in a position identical to that of the figures 8 Or 19. Indeed, without sufficient driving force, they will only be able to come to bear against one or the other of the arming beaks 36a, 36b of the arming lever 10 without succeeding in making it move because the latter, via its arming tenons 34a, 34b, is in a position imposed by the leaf spring 6; the trigger lever 12 and the locking lever linked by the unlocking pin 24 are under the influence of the leaf spring 6 in a position of stability identical to that of the figures 8 Or 19, the detent lever 12 wishing to be pressed against one or the other of the clamps 8a, 8b; the balance 2a is under the influence of the spiral spring 2b and would like to be on the center line. The plate pin 22 being in the horn entry of the detent fork 16 of the detent lever 12, said detent lever 12 is just slightly detached from the clamp 8a or 8b, because the leaf spring 6 is not strong enough to completely counter the torque of the hairspring 2b. at the moment when the driving force becomes insufficient, the balance 2a thanks to the stored kinetic energy will still perform a few alternations and become a motor on the leaf spring 6 until the complete stop of all the elements of the mechanism. The arming lever 10 positioned by the leaf spring 6 via its arming tenons 34a, 34b and the eyelets 6a, 6b, can be located on the passage of the resting beaks 58a, 58b of the locking lever 14.Advantageously, thanks to its inclined planes 66a, 66b, the locking lever 14 will push the inclined planes of the resting beaks 46a, 46b of the arming lever 10 and release the latter towards its central position so as not to damage anything.

[0058] The escapement mechanism 1 is in position to initiate a self-start phase in accordance with the invention, explained below with reference to figures 21 to 35 .

[0059] In reference to the figure 21 , the elements of the escapement mechanism 1 are in position as described above in a stopping phase: the wheel set 4 and the winding wheels 40, 40 are stopped, the position of the winding lever 10 is influenced by the leaf spring 6 and the position of the detent lever 12 is slightly detached from the springs, here the spring 8b, under the influence of the balance spring 2b. The balance wheel 2a is stopped.

[0060] In reference to the figure 22, when a user powers the power source, for example by winding a barrel, the wheel set 4 begins to rotate counterclockwise. The winding wheels 40a, 40b begin to rotate clockwise until one of the winding stars 38a or 38b encounters the corresponding winding beak 36a, 36b of the winding lever 10. Here it is the right winding star 38b which will encounter the right winding beak 36b of the winding lever 10 so that the winding lever 10 is pushed counterclockwise. The leaf spring 6 being already positioned on this side, the winding pins 34a, 34b of the winding lever 10 can move freely in the eyelets 6a, 6b and bring the right winding star 38b to the end of the drive. The locking lever 14 is positioned by the trigger lever 12.This not being pressed against the clamps 8a, 8b under the influence of the balance spring 2b as described above, the left resting beak 46a of the winding lever 10 does not come into contact with the left resting beak 58a of the locking arm 56a of the locking lever 14 by being housed in the recess 68 close to its second inclined plane 66, as shown in the detail at . figure 23 on which the terminal mobile 4 is not shown. Thus, the locking lever 14 leaves the passage free for the winding lever 10. It should also be noted that following a shock or a disturbance, the winding lever 10 by its inclined starting planes 61a, 61b, will be able to release the locking lever by working on its inclined planes 66a, 66b so as to impart a small movement to the balance 2a.

[0061] In reference to the figure 24, following the end of the driving of the right winding star 38b, it leaves the right winding beak 36b of the winding lever 10. As a result, the gear train falls until a tooth of the left winding star 38a comes into contact with the left winding beak 36a of the winding lever 10. The left winding star 38a then drives the winding lever 10 until the winding tenons 34a, 34b of the winding lever 10 come into contact with the eyelets 6a, 6b of the leaf spring 6.

[0062] A first phase of arming the self-start phase can begin with reference to the figure 25, the left winding star 38a being driven by the left winding wheel 40a and working with the left winding beak 36a of the winding lever 10, so that said winding lever 10 will move clockwise. Said winding lever 10 will start to wind the leaf spring 6 in a clockwise movement by means of its winding tenons 34a, 34b working in the eyelets 6a, 6b of the leaf spring 6. The detent lever 12 under the influence of the torque of the balance spring 2b is not pressed against the pins 8a, 8b, as explained above. This forces the detent lever 12 to pivot about the inflection point I to follow the clockwise movement of the leaf spring 6, driving the balance wheel 2a via the plate pin 22 caught in the detent fork 16. The balance wheel 2a will begin to rotate counterclockwise towards the center line.

[0063] Unlike a normal operating cycle during which the winding of the leaf spring 6 presses the trigger lever 12 against one of the clamps 8a, 8b, due to the balance 2a which is in its additional arc, the plate pin 22 being outside the entry of the trigger fork 16 as described above in relation to the figures 8 to 10 , the winding of the leaf spring 6 during the self-start phase takes the detent lever 12 in the direction of the winding of the leaf spring 6. The balance spring 2b also helps to detach the detent lever 12 from the balance springs 8a, 8b because its torque tends to bring the balance wheel 2a back to the center line.

[0064] In reference to the figure 26, the winding of the leaf spring 6 in the clockwise direction continues, the left winding star 38a rotating clockwise pushing the left winding beak 36a of the winding lever 10, so that said winding lever 10 will move in the clockwise direction. The leaf spring 6 takes with it the detent lever 12 in the clockwise direction which itself moves the locking lever 14 in the counterclockwise direction so that said locking lever 14 is positioned so that the right rest beak 46b of the winding lever 10 in angular movement in the clockwise direction can push the first chamfered inclined plane 64 of the inclined planes 60b of the right locking arm 56b opposite the locking lever 14, here the first right inclined plane 64, as shown in the detail at figure 27 .

[0065] With reference to the detail view of the figure 28on which the terminal mobile 4 is not shown, the winding lever 10 continues its rotation in the clockwise direction still under the action of the left winding star 38a pushing the left winding beak 36a of the winding lever 10. Thus, the right starting inclined plane 61b of the winding lever 10, which has become driving, pushes on the second right inclined plane 66b of the locking lever 14, which will drive it in the counterclockwise direction. The locking lever 14 in turn becomes driving, its movement being communicated to the detent lever 12 and to the balance 2a via the fork 26 and the detent pin 24 then via the detent fork 16 and the plate pin 22. Thus, the detent lever 12 becomes driving under the action of the locking lever 14, itself pushed by the winding lever 10.The detent rocker 12, which has become a driving mechanism, moves the balance wheel 2a counterclockwise out of the lifting angle by means of its detent fork 16 working with the plate pin 22, which sets said oscillating regulator 2 in motion, the balance wheel 2a beginning to rotate.

[0066] In reference to the figure 29 , the trigger lever 12 continues to rotate clockwise and, if the winding of the leaf spring 6 by the winding pins 34a, 34b inserted in the eyelets 6a, 6b of the leaf spring 6 is sufficient, forces said leaf spring 6 to pass beyond its instability to return to a stable mode opposite to the stable mode shown in the figure 26 .

[0067] By returning to a stable position, the leaf spring 6 becomes a motor on the trigger lever 12 which, via its trigger fork 16 working with the plate pin 22, gives an impulse to the balance 2a, which promotes its self-starting, as shown in the figure. figure 30 The trigger lever 12 is momentarily pressed against the left clamp 8.

[0068] The inclined planes 66a, 66b of the locking lever 14 and the starting inclined planes 61a, 61b of the winding lever 10 are configured so that the winding lever 10 imposes on the locking lever 14, the detent lever 12 and the oscillating regulator 2 an ideal position to be reached, the balance 2a then being forced into a position outside the lift angle and the winding lever 10 then being free to move.

[0069] More particularly in relation to the figure 31, the trigger lever 12, having pressed against the left clamp 8a, puts the locking lever 14 in position in order to allow the right resting beak 46b of the arming lever 10 to pass which can engage in the right recess 68 of the right locking arm 56b. Thus, the winding lever 10 cannot stop on the right resting beak 58b of the locking lever 14. The winding lever 10 can then move freely, driven by the driving train, while imposing on the balance 2a its position outside the lifting angle maintained by the winding lever 10, the locking lever 14 and the detent lever 12, until the left winding star 38a driven by the mobile 4 finishes its drive on the left winding beak 36a of the winding lever 10 and falls until the right winding star 38b comes into contact with the right winding beak 36b of the winding lever 10, as shown in the figure 32 .

[0070] The escapement train driven by the driving source can then rotate so that the right winding star 38b driven by the wheel set 4 arms the winding lever 10 in the counterclockwise direction by its right winding beak 36b until the left locking beak 46a of the winding lever 10 comes into abutment against the left locking beak 58a of the left locking arm 56a of the locking lever 14, as shown in figure 33 and in detail view figure 34 . During this movement of the winding lever 10, its winding tenons 34a, 34b have wound the leaf spring 6 via its eyelets 6a, 6b. The leaf spring 6 is now wound close to instability. The escapement mechanism is then in a position corresponding to a locking phase ready to be followed by an unlocking phase and an impulse phase of normal operation. The balance 2a is still in its additional ascending arc.

[0071] In reference to the figure 35, the gear train is now stopped and the leaf spring 6 is armed close to instability. The return of the balance wheel 2a in the clockwise direction will bring the plate pin 22 into the detent fork 16 and release the leaf spring 6 so that it gives its impulse to the balance wheel 2a. This configuration is identical to that described in figure 11 which corresponds to a classic impulse of normal operation. From this stage, the escapement has completed its self-start phase and will operate in a classic manner, as described above with reference to the figures 8 to 20 .

Claims

1. Escapement mechanism (1) arranged to provide mechanical impulses from a driving source to an oscillating regulator (2) of a watch movement by means of a leaf spring (6) working in buckling around an inflection point (I), said mechanism comprising a winding lever (10), a detent lever (12) and a locking lever (14) of the winding lever (10) arranged in kinematic connection with the detent lever (12), said leaf spring (6) being capable, in normal operation, by means of said winding lever (10), said locking lever (14) and said detent lever (12), of accumulating the energy from the driving source transmitted by winding wheels (40a, 40b) during a winding phase, of then remaining in a wound state during a locking phase, then of restoring the energy accumulated in said oscillating regulator (2) during a pulse phase preceded by an unlocking phase,said locking lever (14) comprising two locking arms (56a, 56b) each provided with a locking member (58a, 58b) arranged to cooperate with a respective complementary locking member (46a, 46b) of the arming lever (10) to block said arming lever (10) during the locking phase, , characterized in thateach locking arm (56a, 56b) of said locking lever (14) comprises, at its free end, at least one inclined plane (66a, 66b) configured to cooperate with a starting inclined plane (61a, 61b) provided in correspondence on the winding lever (10) during a self-start phase during which an activation of the motive source causes an angular movement of the winding lever (10) whose free passage is allowed by the locking lever (14) until then positioned by the detent lever (12) under the influence of the oscillating regulator (2) at a standstill, said angular movement of the winding lever (10) causing a displacement of the locking lever (14) by pushing one of the starting inclined planes (61a, 61b) of the winding lever (10) onto the corresponding inclined plane (66a, 66b) of the locking rocker (10), so that said locking rocker (14), via the trigger rocker (12),rotates the oscillating regulator (2) out of the lift angle, the escapement mechanism (1) being positioned in a position corresponding to a locking phase ready to be followed by an unlocking phase and an impulse phase of normal operation., 2. Escapement mechanism (1) according to claim 1, characterized in that the inclined planes (66a, 66b) of the locking lever (14) and the starting inclined planes (61a, 61b) of the winding lever (10) are configured so that, during the self-start phase, the winding lever (10) positions the locking lever (14), the trigger lever (12) and the oscillating regulator such that the winding lever (10), driven by the energy of the driving source, is free to move until the end of being driven by one of the winding mobiles (40a, 40b) and the latter falls.

3. Escapement mechanism (1) according to one of the preceding claims, characterized in thatthe inclined planes (66a, 66b) of the locking lever (14) are configured to push on the corresponding starting inclined plane (61a, 61b) of the winding lever (10) in order to move said winding lever (10) away from the locking members (58a, 58b) of the locking lever (14) when the driving energy becomes insufficient to drive the winding lever (10).

4. Escapement mechanism (1) according to one of the preceding claims, characterized in that the locking lever (14) comprises a rod (50) provided at a first end with a fork (26) for connection to the trigger lever (12), the two locking arms (56a, 56b) extending from a second end symmetrically relative to the longitudinal axis of the rod (50).

5. Escapement mechanism (1) according to claim 4, characterized in thatthe fork (26) of the locking lever (14) comprises two horns (26a, 26b) delimiting a space between horns (54) in which an unlocking pin (24) integral with the trigger lever (12) cooperates.

6. Escapement mechanism (1) according to claim 5, characterized in that the rod (50) of the locking lever (14) has a length between its pivot center passing through the pivot axis (48) and the functional part of the inter-horn space (54) which is greater than or equal to twice the length of the trigger lever (12) between its inflection point (I) and the unlocking pin (24).

7. Escapement mechanism (1) according to one of claims 4 to 6, characterized in thateach locking arm (56a, 56b) of the locking lever (14) successively comprises, in the direction of its free end, a first segment having, on its inner face facing the rod (50), a surface concentric with the pivot axis (48) of the locking lever (14) and a second segment (62a, 62b) of lesser thickness, having on its inner face facing the rod (50), a surface concentric with the pivot axis (48) of the locking lever (14), the first segment forming a resting beak constituting the locking member (58a, 58b), said first and second segments being connected by a first inclined plane (64) to form a chamfer for the locking member (46a, 46b) complementary to the arming lever (10),a second inclined plane (66) forming an obtuse angle with the surface concentric with the pivot axis (48) of the locking lever (14) of the first segment chosen so that the contact of the starting inclined plane (61a, 61b) of the arming lever (10) in motion with said second inclined plane (66) causes a rotation of the locking lever (14) about its pivot axis (48), and a recess (68) configured to allow the complementary locking member (46a, 46b) of the arming lever (10) to be able to engage therein., 8. Escapement mechanism (1) according to the preceding claim, characterized in thateach locking arm (56a, 56b) comprises, on the surface concentric with the pivot axis (48) of the locking lever (14) of the second segment (62a, 62b), a groove (70a, 70b) extending perpendicular to the upper and lower faces of the locking arm (56a, 56b), the portion of said second segment (62a, 62b) between the recess (68) and the groove (70a, 70b) being arranged to constitute a clamp (71a, 71b) to prevent excessive angular displacement of the arming lever (10).

9. Escapement mechanism (1) according to one of the preceding claims, characterized in thatit comprises two winding mobiles (40a, 40b) each comprising an escape pinion (42a, 42b) intended to mesh with a mobile (4) of the finishing gear of the watch movement to pivot simultaneously in the same direction around separate axes of rotation and a winding star (38a, 38b) intended to cooperate with a winding beak (36a, 36b) provided at the end of a winding arm (30, 32) of the winding lever (10), the indexing of these winding mobiles (40a, 40b) being such that when one of the winding beaks (36a, 36b) is in contact with one of the winding stars (38a, 38b), the other winding beak (36a, 36b) is not in contact with the other star of armament (38a, 38b).

10. Escapement mechanism (1) according to the preceding claim, characterized in that each winding wheel (40a, 40b) comprises an inertia wheel (44a, 44b).

11. Watch movement comprising an escapement mechanism (1) according to one of claims 1 to 10.

12. Timepiece comprising an escapement mechanism (1) according to one of claims 1 to 10 or a watch movement according to claim 11.

Images