EP3273308B1 - Exhaust mechanism - Google Patents

Description

Technical area

The present invention relates to the field of mechanical watchmaking. It relates, more particularly, to an escapement mechanism arranged to transmit mechanical energy pulses from a driving source to an oscillating timepiece regulator by means of a leaf spring working in buckling around a inflection point. The leaf spring is capable of accumulating energy from the power source between two pulses and transmit it to said oscillating regulator at each pulse via a first and a second latch.

State of the art

Such a mechanism is described in particular in the document WO 99/64936 . The latter more generally discloses a method for transmitting pulses of mechanical energy from a power source to an oscillating regulator, by means of a leaf spring working in buckling mode. More particularly, this method is implemented in particular by an escape mechanism illustrated in FIG. figure 1 , intended to maintain the oscillations of a regulator, composed for example by a balance 1 associated with a spiral, by delivering energy received from a driving source, such as a barrel for example, not visible on the figure 1 , via a leaf spring 2, whose ends are positioned such that it occupies a stable position corresponding to a second mode buckling. The leaf spring 2 is capable, by means of an armature rocker 3 and a trigger rocker 4, of accumulating the energy coming from the driving source during a winding phase, to remain in an armed state during a rest phase and to restore the energy accumulated to said oscillating regulator during a pulse phase.

The trigger rocker 4 is kinematically connected to the leaf spring 2 substantially at its central point of inflection. The trigger rocker 4 comprises, at one end, a fork intended to cooperate with a plate 6 and a plate pin 7 that includes the rocker 1.

The armature rocker 3 comprises a central portion and two symmetrical wings whose ends are kinematically connected to the leaf spring 2. The central portion comprises a first 8 and a second 9 pallets of rest, intended to cooperate respectively with a first 10 and a second 11 escape wheel.

The two flip-flops 3 and 4 are mounted free to rotate with respect to each other.

The wheels 10 and 11 each comprise a pinion meshing with the last wheel 12 of the work train so that the wheels 10 and 11 pivot in a synchronized manner. The wheels 10 and 11 have a particular toothing, the shape of which is adapted to cooperate with the first 8 and second 9 pallets of rest of the rocker arm 3, on the one hand to transmit energy to this rocker d ' arming 3 and, secondly, to block the rotation of the escape wheels 10 and 11, according to the phases of operation which will be summarized below. For more details, it is possible to refer to the document cited in the introduction.

The figure 1 represents an exhaust mechanism of the prior art immediately after a pulse phase and at the beginning of a winding phase, the rocker 1 rotates counterclockwise, the plateau pin 7 comes out of the fork, the first pallet rest 8 has just disengaged from the wheel 10 and the spring 2 is in a stable position corresponding to a second mode buckling. During the arming phase, while the rocker 1 performs its supplementary arc, the first escape wheel 10 rotates freely and the second escape wheel 11 cooperates with the second pallet of rest 9 of the rocking lever 3 to rotate the latter counterclockwise until a tooth of the second wheel 11 bears on the second pallet rest 9. Concomitantly, the leaf spring 2 has left its initial stable state corresponding to a second mode buckling and deformed under the action of the armature rocker 3 to a metastable state close to an unstable state corresponding to a fourth mode buckling. The armature of the leaf spring 2 is then maximal.

During the following rest phase, the escape wheels 10, 11 are stopped, a tooth of the second wheel 11 bearing against the second pallet of 9. The balance 1 continues its oscillation until the pin 7 hits the fork of the trigger rocker 4 which marks the beginning of the pulse phase.

During the pulse phase, the trigger rocker 4 pivots by acting on the leaf spring 2 which then suddenly switches from its unstable position to a stable state corresponding to a reverse second mode buckling of the previous one. This change of state rotates the armature lever 3, causing the release of the second pallet of rest 9 of the second escape wheel 11. The armature rocker 3 pivots until the first pallet of rest 8 when the spring wheel 2 is being changed, the latter also acts on the trigger rocker 4, thus communicating with the balance 1 the energy accumulated during the winding of the spring -lame 2, through the fork.

During the next alternation, the phases described above reproduce symmetrically with respect to the plane passing through the axes of rotation of the balance 1, the trigger rockers 4 and armature 3 and the point of inflection of the spring -lame 2.

Such an escape mechanism makes it possible, in particular, to maintain oscillations of the balance arm steadily over the entire duration of the power reserve, independently of the torque variations of the energy source.

The draw of the escape wheels 10 and 11 on the first 8 and second 9 pallets of rest of the rocker arm 3 makes it possible to ensure the locking function of the escape wheels. The pulling force must be sufficient to avoid unwanted unlocking which could, for example, result from accelerations experienced by the timepiece in everyday use and which would lead to an advance of the timepiece's running and an overconsumption of time. 'energy. Conversely, the pulling force must be as small as possible in order to limit the energy required to achieve the clearance and thus optimize the power reserve. It has been found that it is not possible to adjust the draft of the escape wheels 10 and 11 satisfactorily so as to together, to obtain a sufficient locking force and a moderate energy consumption.

The present invention aims to overcome this disadvantage.

Disclosure of the invention

This object is achieved through an exhaust mechanism whose features are detailed in the claims.

More particularly, the escapement mechanism of the invention is designed to transmit pulses of mechanical energy from a driving source to an oscillating timepiece regulator via a leaf spring working in buckling around a point of inflection, said leaf spring being capable of accumulating energy from the power source between two pulses and to transmit it to said oscillating regulator at each pulse by means of a cooperating armature latch with the leaf spring and a trigger rocker adapted to cooperate with at least one escapement mobile receiving energy from the drive source to block its rotation intermittently.

• une fourchette et un dard aptes à travailler avec le régulateur, et
• au moins deux ergots de verrouillage agencés pour bloquer le mobile d'échappement pendant les phases de repos,

de sorte que le dégagement de la bascule de verrouillage est déclenché par une action du régulateur sur ladite fourchette indépendamment du ressort-lame dans le transfert de l'énergie du dégagement.The escape mechanism of the invention is characterized in that the armature and trigger rockers and the escape wheel are arranged relative to the leaf spring so that the locking and unlocking functions of the mobile on the one hand, and the arming functions of the leaf spring on the other hand, are dissociated, the trigger rocker comprising a latching lever comprising:

• a fork and a dart able to work with the regulator, and
• at least two locking lugs arranged to block the escape wheel during the rest phases,

so that the release of the latch is triggered by an action of the regulator on said fork independently of the leaf spring in the transfer of the energy of the disengagement.

Preferably, the escape mobile comprises a pinion adapted to kinematically bind said mobile escape to the power source.

In one embodiment of the invention, the escape wheel comprises a locking wheel comprising a plurality of functional zones each having a locking plane intended to cooperate with a lug of the trigger rocker to block the escape wheel during the rest phases. In addition, the escapement mobile also includes a winding cam.

According to a particular embodiment of the invention, the armature rocker comprises at least one lever adapted to cooperate with the arming cam of said at least one escapement mobile.

Advantageously, the exhaust mechanism comprises at least one said mobile escapement and the armature rocker comprises at least one lever, optionally associated with a return spring for example, which cooperates with the arming cam of said mobile exhaust, the arming cam comprising N functional areas and being indexed with an offset of 360 / N °. In addition, the lever or levers are dimensioned and positioned to always be in contact with said arming cam.

In a particular embodiment, the lever or levers are arranged on an arm integral with the armature rocker, and the lever or levers are sized and positioned to always be in contact with at least one arming cam.

Preferably, the lever or levers and the arming cam are shaped to limit unintentional angular displacements of the armature rocker once it has reached one of its extreme positions in rotation about its axis.

Brief description of the drawings

• les figures 2 à 6 représentent différentes phases du fonctionnement d'un mécanisme d'échappement selon l'invention,
• les figures 7 et 8 montrent certains détails d'un mobile d'échappement et d'une bascule de détente utile dans le mécanisme d'échappement selon l'invention,
• la figure 9 montre un exemple d'une bascule d'armage utile dans le mécanisme d'échappement selon l'invention.

Other features of the present invention will emerge more clearly on reading the description which follows, made with reference to the appended drawing, in which, in addition to the figure 1 described above with reference to the state of the art:

• the Figures 2 to 6 represent different phases of the operation of an exhaust mechanism according to the invention,
• the Figures 7 and 8 show some details of an escape wheel and a trigger rocker useful in the exhaust mechanism according to the invention,
• the figure 9 shows an example of an armature rocker useful in the exhaust mechanism according to the invention.

Mode (s) of realization of the invention

We have shown on the figure 2 an escape mechanism arranged to transmit pulses of mechanical energy from a driving source to an oscillating timepiece control unit, in particular of the pendulum type 1, by means of a leaf spring 2 working in buckling around a point of inflection. The leaf spring 2, constrained in buckling at its ends by any appropriate means, for example integral with a frame sized to constrain said leaf spring and adapted to be fixed on a bridge or the plate of a timepiece or simply fixed directly on a said bridge or the turntable of a timepiece, is capable of accumulating energy from the power source between two pulses and transmit it to the oscillating regulator at each pulse via of a trigger rocker 25 pivotally mounted about an axis X1 coincides with the point of inflection of the leaf spring 2. The armature rocker 3 comprises two connecting arms 31 to the leaf spring 2 extending from the X1 axis and each having between their end opposite said axis X1 pins 13a cooperating with eyelets 13b integral with the leaf spring 2.

• une bascule de verrouillage 20, représentée en détail sur la figure 8, qui est également montée pivotante autour de l'axe X1 et comporte à une extrémité une fourchette 24 apte à coopérer avec une goupille de plateau du régulateur,
• une bascule d'impulsion 4 solidaire de la lame-ressort 2 et s'étendant dans un même plan que des étoqueaux E, la bascule d'impulsion 4 comportant en outre à une extrémité une fourchette 41 apte à coopérer avec lesdits étoqueaux pour assurer le positionnement de la bascule de détente 25 dans ses positions extrêmes, et
• un dard 22, destiné à coopérer de manière classique avec une encoche de plateau du régulateur à chaque alternance de celui-ci.

The escapement mechanism also includes a trigger rocker comprising:

• a latching lever 20, shown in detail on the figure 8 which is also pivotally mounted about the axis X1 and has at one end a fork 24 adapted to cooperate with a platen pin of the regulator,
• a pulse rocker 4 integral with the leaf spring 2 and extending in the same plane as star E, the pulse rocker 4 further comprising at one end a fork 41 adapted to cooperate with said star to ensure the positioning the trigger rocker 25 in its extreme positions, and
• a dart 22, intended to cooperate in a conventional manner with a plateau notch of the regulator at each alternation thereof.

The latch 20 advantageously cooperates via anterior pins 26a and 26b rear with an escapement mobile 28 of the leaf spring 2 to block the rotation of the escapement mobile 28 intermittently, said mobile of exhaust 28 is in kinematic connection with the driving source.

The latch 20 is integral with the pulse rocker 4, and the dart 22 and they are assembled by pins or any other means, which ensure their respective angular positioning around the axis X1 in a safe way. Preferably, the latch 20, the pulse rocker 4 and the dart 22 respectively extend in longitudinal directions located in the same vertical plane passing through the axis X1.

The armature rocker 3, on the one hand, and the trigger rocker 25, on the other hand, are rotatably mounted one with reference to the other on a pivoting material axis coinciding with the axis X1 , the leaf spring 2 not participating in a virtual pivoting of the armature and trigger rockers 25.

As represented in figure 7 , the escape wheel 28 comprises a pinion 32 by which it is kinematically connected to the finishing gear of the timepiece comprising the exhaust mechanism for receiving energy from the energy source, for example consisting of one or more barrels. The escapement wheel 28 further comprises, stacked on the same axis, a winding cam 36, for example a triangular cam with convex cam planes, the role of which will appear below, as well as a locking wheel 38. The arming cam 36 and the locking wheel 38 each comprise a plurality of functional zones, the angular position of which is adjusted with reference to each other.

Each functional zone of the locking wheel 38 comprises a locking plane 40 intended to cooperate with the latch 20. The locking plane 40 is preferably located in the plane of the locking wheel 38, which can thus be manufactured easily.

As is apparent from the figure 8 in particular, the latch 20 comprises a fork 24. This fork 24 is adapted to cooperate with the regulator 1, and more particularly with a plate pin 7 as shown in FIGS. Figures 2 to 6 of the regulator 1, as in the case of a regulating system cooperating with a conventional Swiss anchor escapement.

The latching lever 20 also comprises anterior locking lugs 26a and posterior 26b arranged to lock the escape wheel 28 during the rest phases, by working with the locking planes 40 of the locking wheel 38.

In operation, on the figure 2 , the mechanism is illustrated when the trigger rocker 25 has been positioned by the change of buckling mode of the leaf spring 2. The trigger rocker 25 and the rocker arm 3 are then in the input or anterior position, side mobile exhaust 28, under the action of the previous locking pin 26a and the locking wheel 38, which transmits the torque provided by the energy source. This torque provides a pull on the trigger rocker 25 via the front lug 26a, against which a locking plane 40 is supported. The pair presses the fork of the pulse rocker 4 against one of the stars E, in order to always definitively define the position of the pulse rocker 25. The armature rocker 3 is also positioned directly by the cam of the armature 36 and not by the leaf spring 2. The escape wheel 28 is stopped.

During the rotation of the regulator, the plate pin 7 that it comprises enters the fork 24 of the latch 20. The leaf spring 2 then leaves its unstable mode of second order and repositioned in buckling of 1 ^st order, thus providing all its energy to the regulator through the fork 24 of the latch 20 and the plate pin 7 of the regulator. During the pulse, the trigger rocker 25 pivots around the axis X1 and moves from a first position in abutment against a first star E to a second position abutting against the second star E ( Figures 3 to 6 ). This movement releases the latch 20 from its support against the locking wheel 38 at the front pin 26a, thus releasing the escapement wheel 28 which then rotates.

The latch 20 is then positioned to receive, in abutment against the output or rear locking pin 26b at a locking plane 40 of the locking wheel 38. The locking plane 40 of the locking wheel 38 transmits the torque provided by the energy source to the trigger rocker via the rear lug 26b. This torque provides a pull on the latch 20 and the trigger rocker 25 and thus presses the pulse latch 4 against one of the star E, to always definitively determine the position of the trigger rocker 25. The armature rocker 3 is also positioned directly via the arming cam 36. The leaf spring 2 is armed, close to its unstable position and waiting for the ankle 7 during the next alternation.

Thus, thanks to this arrangement, the release of the latch 20 is triggered by an action of the regulator 1 on the fork 24 without intervention of the leaf spring 2 in the transfer of the energy of the release. There is thus a dissociation of the locking and unlocking functions of the escapement wheel 28 on the one hand, and the arming functions of the leaf spring 2. In addition, an efficient draft is obtained which improves the safety of the functions on the front wheel. 'exhaust.

If one of the aims of the invention is to separate the setting of the locking / unlocking phases, on the one hand, and arming, on the other hand, it remains the case that these functions must be synchronized . To do this, the armature rocker 3 also comprises, as represented on the Figures 2 to 6 and in detail at the figure 8 two levers 50 shaped to cooperate with the arming cam 36 of the escapement wheel 28. The arming cam 36, visible on the figure 7 in particular comprises N functional areas consisting of cam segments 36a, 36b, 36c. The cam 36 of the escapement wheel 28 is indexed with an offset of 360 ° / N. The levers 50 are dimensioned and positioned to be in permanent contact with the arming cam 36, the angular position of said cam 36 thus making it possible to perfectly position the armature rocker 3, in synchronism with the locking wheel 38. example shown on Figures 2 to 6 , the cam 36 is essentially triangular, the 3 cam segments 36a, 36b, 36c being convex to define a point contact with the levers 50 of the armature rocker 3 and optimize the friction.

The levers 50 may be formed of the branches of a fork 52 in U carried at the end of an arm 53, the fork being shaped and dimensioned so that the arming cam 36 of the mobile 28 is inserted between the branches the U in permanent and punctual contact with the cam 36, which ensures a perfect positioning and an angular locking of the armature rocker 3.

The levers 50 and the arming cam 36 may of course adopt other shapes than that shown in FIG. figure 9 , depending on the particular geometry of the arming cam 36. In particular it could be considered to use only one lever 50 associated with a return spring to cooperate with said arming cam 36. Whatever its shape, each lever 50 allows, in cooperation with the arming cam 36 of the escapement wheel 28 on the one hand and the pins 13a of the connection of the armature rocker 3 to the leaf spring 2 in the corresponding eyelets 13b on the other hand to reset the leaf spring 2 to a defined optimum point and angularly locked by the geometry of the arming cam 36 and levers 50 for the next pulse. This rearming results from the pivoting of the armature lever 3 around the axis X1 containing the point of inflection of the leaf spring 2 under the leverage applied to the levers 50 by the arming cam 36, which generates level of the pins 13a of the armature rocker a traction action on the leaf spring substantially in the center of the two segments of said spring on either side of the point of inflection on the axis X1, and thus a second order buckling of the leaf spring 2 which then adopts the configuration shown in FIGS. Figures 4 to 7 in which it is reset until the next pulse.

The exhaust mechanism of the invention has been described here with reference to the appended figures in an embodiment comprising a single exhaust mobile 28 cooperating with the trigger rocker 25 via the latch 20 incorporated in the latter. However, those skilled in the art can easily make a similar exhaust mechanism comprising two symmetrical armoring mobiles 28 cooperating alternately with each alternation with the trigger rocker 25 by adjusting differently the pins 26a, 26b on the latch and by providing a kinematic connection of the two armoring mobiles between them to ensure synchronization in rotation, for example by means of a toothed gear coaxial with the locking wheels and arming cams of each of the armoring mobiles, identical. It will then be ensured to ensure a geometry of the levers 50 of the armature rocker allowing an alternating contact with the winding cams of each of the two symmetrical armoring mobiles while ensuring a locked position angularly of this rocker.

It will also be possible to realize the escape mechanism of the invention by implementing a simple blade whose one end is located on the axis of rotation of the trigger rocker. Such a configuration makes it possible in particular to reduce the size of the exhaust mechanism of the invention.

Claims (7)

1. Escapement mechanism designed to transmit impulses of mechanical energy from a drive source to an oscillating regulator (1) of a timepiece via a spring blade (2) which acts by buckling about an inflection point, said spring blade (2) being able to accumulate the energy from the drive source between two impulses and to transmit it to said oscillating regulator (1) at each impulse via a winding lever (3), capable of interacting with the spring blade (2) and a detent lever (25), capable of interacting with at least one escapement wheel (28) receiving energy from the drive source to block the rotation thereof intermittently,
   characterised in that the detent lever (25) comprises a locking lever (20) comprising:

   - a bracket (24) capable of acting with the regulator (1), and

   - at least two locking lugs (26) designed to block the escapement wheel (28) during the locking phases,

   such that the release of the locking lever (20) is triggered by an action of the regulator on said bracket independently from the spring blade (2) in the transfer of the energy from the release, the locking and unlocking functions of said escapement wheel (28) on the one hand, and the winding functions of the leaf spring (2) on the other hand thus being dissociated.
2. Escapement mechanism according to claim 1, characterized in that the escapement wheel (28) comprises a pinion (32) adapted to kinematically connect said escapement wheel with the power source.
3. Escapement mechanism according to one of the preceding claims, characterized in that the escapement wheel (28) comprises a locking wheel (38) comprising a plurality of functional zones, each having a locking plane (40) intended to interact with a lug (26a, 26b) of the locking lever (20) to block the escapement wheel (28) during the locking phases.
4. Escapement mechanism according to one of the preceding claims, characterized in that the winding lever (3) includes at least one lever (50) capable of interacting with the winding cam of said escapement wheel (28).
5. Escapement mechanism according to claim 4, characterized in that the at least one lever (50) interacts with a winding cam (36) of the escapement wheel (28), said winding cam (36) comprising N functional zones, and being indexed with an offset of 360°/N, and in that the lever (50) is dimensioned and positioned to always be in contact with said winding cam (36).
6. Escapement mechanism according to claim 4 or 5, characterized in that the at least one lever (50) is arranged on an arm secured to the winding lever, and in that said lever (50) is so dimensioned and positioned as to always be in contact with the winding cam (36).
7. Escapement mechanism according to claims 4 to 6, characterized in that the lever (50) and the winding cam (36) are arranged to limit the undesired angular displacements of the winding lever (3).

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