EP2706416B1 - Constant force flexible anchor - Google Patents

Description

Field of the invention

The invention relates to a clockwork escapement anchor, comprising an anchor head carrying at least one entry pallet and / or an exit pallet and arranged to cooperate with an escape wheel, and further comprising a fork arranged to cooperate with a rocker, where the angular position of said relative to said head is variable, where the only direct permanent mechanical connection between said head and said fork is provided by at least one flexible blade, and where the angular displacement in pivoting of said head and that of said fork are limited relative to each other by stops, and wherein said head comprises at least a first arm having a first bearing surface and abutment arranged to cooperate, in abutting or resting, in certain relative positions of said head and of said fork, with a second bearing and abutment surface that comprises at least one second arm that comprises said fork

The invention also relates to a clock escapement mechanism, comprising at least one plate carrying an escape wheel and a balance cooperating with the same anchor.

The invention also relates to a watch movement comprising at least one such escape mechanism.

The invention also relates to a timepiece comprising at least one such watch movement, and / or at least one such escape mechanism.

The invention relates to the field of watch exhaust mechanisms.

Background of the invention

The regularity of the operation of an escape mechanism is conditioned by a good control of the maintenance of the oscillations and in particular the impulse, whose intensity can be irregular in a watch whose torque varies.

The search for an optimal safety of operation is a constant preoccupation of watch movement designers.

The document FR 2 928 015 A1 in the name of LENOBLE describes a tangential pulse anchor escapement device for a watch, comprising a toothed escape wheel, an anchor and at least one balance spring. The anchor is in two parts each pivoting on a separate axis, the two parts are hinged together by two transmission arms terminating at their adjacent ends by a common joint to rotate the two parts of the anchor at the same speed but in opposite directions. Each part of the anchor comprises a rest lift and a pulse lift, the latter receiving thrusts of the teeth of the escape wheel in a tangential manner. This escapement device comprises two spiral rockers with distinct oscillating axes of rotation, and each part of the anchor comprises a fork that can engage drive on an ellipse of the corresponding balance spring.

The document WO2011 / 064682 A1 in the name of FERRARA concerns an anchor in two parts hinged together, the hinge comprising an eccentric cam integral with the part of the anchor carrying the horns and the dart, and cooperating with a fork secured to the part of the anchor carrier pallets.

The document EP 2 444 860 A1 in the name of AUDEMARS PIGUET RENAUD PAPI and describes an anchor which has two parts each pivoting about an axis, and are articulated to each other, the pivoting of one of the parts causing the pivoting of the other with a amplitude of higher value.

The document EP 2,105,806 in the name of GIRARD PERREGAUX describes an escape mechanism arranged to transmit pulses from a power source to an oscillating regulator such as a balance-spring, via a leaf spring which works in buckling around a point of inflection. This leaf spring is capable of accumulating the energy of the driving source between two pulses, and of transmitting it to the oscillating regulator at each pulse by means of a first and a second latch. To optimize the adjustment of the tension of the leaf spring, it is mounted on a frame which is deformable symmetrically with respect to a first axis passing through the axes of rotation of the regulator, the first and second latches, and by the point d inflection, as well as with respect to a second axis perpendicular to the first axis and passing through the ends of the leaf spring.

Summary of the invention

The invention proposes, on the one hand, to regulate the intensity of the pulse applied to the pendulum, and on the other hand to reduce the inertia in motion during the oscillation.

For this purpose, the invention relates to a watch exhaust anchor, comprising an anchor head carrying at least one entry pallet and / or an output pallet and arranged to cooperate with an escape wheel. and further comprising a fork arranged to cooperate with a rocker, wherein the angular position of said relative to said head is variable, wherein the only direct mechanical linkage direct between said head and said fork is provided by at least one flexible blade, and wherein the angular pivotal displacement of said head and that of said fork are limited relative to each other by stops, and wherein said head comprises at least a first arm having a first bearing surface and arranged stop to cooperate, in abutment or in abutment, in certain relative positions of said head and of said fork, with a second bearing surface and abutment that comprises at least a second arm that co mporte said fork, characterized in that said anchor is made integrally with said at least one flexible blade.

According to a feature of the invention, said anchor is made of silicon or silicon oxide or metal glass.

The invention also relates to a clockwork escapement mechanism comprising at least one plate carrying an escape wheel and a rocker cooperating with the same anchor, characterized in that said head and said fork are assembled. said platen so that said flexible blade is mounted in buckling preload between said head and said fork, said anchor constituting a bistable system having at least two stable states and two metastable states.

• après rechargement en énergie par ladite roue d'échappement et pendant une phase transitoire, à haute énergie, d'approche d'un premier col d'énergie, avec un profil ondulé en Z;
• après libération de l'énergie dont dispose ladite lame bistable, lors du passage dudit premier col d'énergie, sous forme d'une impulsion donnée audit balancier dans un premier sens, ladite lame occupe une deuxième position stable à basse énergie, avec un profil en arc convexe ;
• après rechargement en énergie par ladite roue d'échappement et pendant une phase transitoire, à haute énergie, d'approche d'un deuxième col d'énergie, avec un profil ondulé en S ;
• après libération de l'énergie dont dispose ladite lame, lors du passage dudit deuxième col d'énergie, sous forme d'une impulsion donnée au balancier dans un deuxième sens opposé audit premier sens, ladite lame occupe une première position stable à basse énergie, avec un profil en arc concave.

According to one characteristic of the invention, said anchor carries out a closed cycle during which said flexible blade successively occupies four main configurations:

• after reloading energy by said escape wheel and during a transient phase, at high energy, approaching a first energy pass, with a Z-shaped corrugated profile;
• after release of the energy available to said bistable blade, during the passage of said first energy collar, in the form of a pulse given to said balance in a first direction, said blade occupies a second stable position at low energy, with a profile convex arc;
• after reloading energy by said escape wheel and during a transient phase, at high energy, approaching a second energy collar, with an S-shaped corrugated profile;
• after release of the energy available to said blade, during the passage of said second energy collar, in the form of a pulse given to the balance in a second direction opposite to said first direction, said blade occupies a first stable position at low energy, with a concave arch profile.

The invention also relates to a watch movement comprising at least one such escape mechanism.

The invention also relates to a timepiece comprising at least one such watch movement, and / or at least one such escape mechanism.

Brief description of the drawings

• la figure 1 représente, de façon schématisée et en vue de dessus un mécanisme d'échappement comportant, entre une roue d'échappement et un balancier classiques, une ancre flexible selon l'invention avec une tête et une fourchette pivotantes et reliées par une lame flexible bistable précontrainte ; ce mécanisme est représenté dans le premier temps d'un cycle d'échappement ;
• les figures 2 à 17 représentent, de façon analogue à la figure 1, les temps successifs de ce cycle ;
• la figure 18 représente, de façon schématisée, un diagramme tridimensionnel représentatif de l'énergie dans la lame flexible bistable ;
• la figure 19 est une projection sur le plan de base du diagramme de la figure 18, sur laquelle un rectangle délimite les variations d'énergie dans la lame flexible bistable pendant le cycle d'échappement ;
• la figure 20 représente le même rectangle, surchargé des positions d'énergie correspondant aux temps T1 à T17 des figures 1 à 17 ;
• les figures 21 et 22 sont des diagrammes-blocs explicatifs des mécanismes à force constante, comportant une ancre flexible en figure 21, une ancre bistable en figure 22 ;
• les figures 23 et 24 sont des illustrations schématiques de deux configurations particulières d'axes de pivotement par rapport à une platine porteuse du mécanisme d'échappement : en figure 23 un premier axe et un deuxième axe de pivotement en positions fixes par rapport à la platine, et en figure 24 le deuxième axe en position mobile, ici en translation, et conjugué avec un moyen de rappel élastique ;
• les figures 25 à 27 représentent, de façon schématisée, des exemples particuliers d'ancre, où seule la tête d'ancre pivote autour d'un axe, la fourchette d'ancre étant montée à une extrémité d'une lame flexible bistable et limitée dans sa course de façon à pré-contraindre cette dernière ;
• les figures 28 et 29 regroupent différents modèles de pivots utilisables notamment pour les variantes des figures 23 et 24 : pivot classique seul, pivot flexible seul, en figure 28, et combinaison d'un pivot classique et d'un guidage d'une certaine rigidité, combinaison d'un pivot flexible et d'un guidage d'une certaine rigidité en figure 29;
• les figures 30 et 31 représentent, en perspective et en plan, un exemple qui ne fait pas partie de l'invention revendiquée, avec deux lames bistables chacune comportant une extrémité fixée à une platine non représentée, la tête et la fourchette, qui sont partiellement superposées et qui pivotent autour d'un même axe géométrique de pivotement, étant reliées par un ressort de rappel ;
• les figures 32 et 33 illustrent des variantes d'ancres à interaction répulsive, chacune avec un ressort, respectivement droit ou en S, précontraint entre la tête et la fourchette de l'ancre ;
• la figure 34 illustre une variante de palette de tête d'ancre ;
• la figure 35 illustre, en coupe, différentes variantes d'aménagement de la platine recevant l'ancre selon l'invention ;
• la figure 36 illustre une configuration où la fourchette est mobile en dehors de l'alignement roue d'échappement-balancier ;
• la figure 37 illustre une autre forme d'ancre à deux lames flexibles bistables ;
• la figure 38 illustre deux variantes d'encastrement de la lame flexible bistable dans la tête et la fourchette d'ancre ;
• la figure 39 illustre une tête à pivot virtuel, incorporée à une ancre selon l'invention,
• la figure 40 illustre sous forme d'un schéma-blocs une pièce d'horlogerie comportant un mouvement équipé d'un échappement avec une ancre selon l'invention.

Other features and advantages of the invention will appear on reading the detailed description which follows, with reference to the appended drawings, in which:

• the figure 1 represents schematically and in top view an escape mechanism comprising, between a conventional escapement wheel and a rocker, a flexible anchor according to the invention with a pivoting head and fork and connected by a flexible bistable prestressed blade ; this mechanism is represented in the first stage of an escape cycle;
• the Figures 2 to 17 represent, in a similar way to figure 1 , the successive times of this cycle;
• the figure 18 schematically represents a three-dimensional diagram representative of the energy in the flexible bistable plate;
• the figure 19 is a projection on the base plane of the diagram of the figure 18 , on which a rectangle delimits the energy variations in the bistable flexible blade during the exhaust cycle;
• the figure 20 represents the same rectangle, overloaded with energy positions corresponding to times T1 to T17 of Figures 1 to 17 ;
• the Figures 21 and 22 are explanatory block diagrams of constant force mechanisms, with a flexible anchor in figure 21 , a bistable anchor figure 22 ;
• the Figures 23 and 24 are schematic illustrations of two particular configurations of pivot axes with respect to a plate carrying the escape mechanism: in figure 23 a first axis and a second pivot axis in fixed positions relative to the platen, and figure 24 the second axis in the mobile position, here in translation, and conjugated with an elastic return means;
• the Figures 25 to 27 schematically represent particular examples of anchor, where only the anchor head pivots about an axis, the anchor fork being mounted at one end of a bistable flexible blade and limited in its stroke so to pre-constrain the latter;
• the Figures 28 and 29 different models of pivots that can be used in particular for the variants of Figures 23 and 24 : classic pivot only, flexible pivot alone, in figure 28 , and combination of a conventional pivot and a guide of a certain rigidity, combination of a flexible pivot and a guide of a certain rigidity in figure 29 ;
• the Figures 30 and 31 represent, in perspective and in plan, an example which does not form part of the claimed invention, with two bistable blades each having an end fixed to a not shown plate, the head and the fork, which are partially superposed and which pivot about of the same geometric axis of pivoting, being connected by a return spring;
• the Figures 32 and 33 illustrate variants of repulsively interacting anchors, each with a spring, respectively straight or S, prestressed between the head and the fork of the anchor;
• the figure 34 illustrates a variation of pallet of anchor head;
• the figure 35 illustrates, in section, different variants of arrangement of the plate receiving the anchor according to the invention;
• the figure 36 illustrates a configuration where the fork is movable outside the wheel-escapement wheel alignment;
• the figure 37 illustrates another form of anchor with two flexible bistable blades;
• the figure 38 illustrates two variants of embedding the bistable flexible blade in the head and the anchor fork;
• the figure 39 illustrates a virtual pivot head, incorporated in an anchor according to the invention,
• the figure 40 illustrates in the form of a block diagram a timepiece comprising a movement equipped with an escapement with an anchor according to the invention.

Detailed Description of the Preferred Embodiments

The invention relates to the field of watch exhaust mechanisms.

To improve the regularity of walking, the invention focuses on good control of the pulse.

A constant force mechanism ensures repeatability over time.

In particular, the use of a bistable element, interposed between the escape wheel and the balance, makes it possible to restore energy to the latter, with a regular intensity, which depends only on the intrinsic characteristics of this bistable element, and not the torque of the barrel, transmitted by the escape wheel. According to the invention, this bistable element is constituted by an anchor of particular constitution.

The figure 21 shows the principle of a constant force mechanism, with a transfer of energy from a barrel 80, through a gear train 81, an escape wheel 20, an anchor 1, to a rocker 30. This mechanism comprises a flexible anchor figure 21 . The figure 22 illustrates the configuration of a bistable anchor. The invention proposes to combine these two architectures mechanisms to achieve maximum regularity, with high security, and a reduced number of components, and a recessless release.

For this purpose, the invention relates to a watch exhaust anchor 1, comprising an anchor head 2, carrier of at least one entry pallet 3 and / or an exit pallet 4, and arranged to cooperate. with an escape wheel 20. The anchor 1 further comprises a fork 6 arranged to cooperate with a rocker 30. According to the invention, the angular position of the fork 6 relative to the head 2 is variable.

According to the invention, a repulsive interaction is created between the head 2 and the fork 6.

It involves transferring energy, discontinuously, from the escape wheel to the balance, through the anchor, which serves as a buffer energy. An object of the invention is to minimize the movements of the components mechanical. The release of energy from the anchor to the pendulum is studied to be in the form of an impulse. Also, the anchor comprises means for storing and releasing energy, according to the respective positions of its moving components, here the head 2 and the fork 6. Note that intermediate stages could be added between the head and the fork, without departing from the invention. The preferred embodiment with a head and a fork has the advantage of minimizing the number of components, especially as it is possible to make a monobloc embodiment.

The present description relates to a preferred embodiment where the repulsive interaction is performed mechanically, with a prestressing of a mechanical element, and more particularly through a bistable blade. Other achievements are possible: such as Figures 32 and 33 , where each anchor comprises a spring, respectively straight 112 or S 113, prestressed between the head 2 and the fork 6. This spring 112 or 113 pushes the two halves of the anchor, and is free to rotate around its ends, the figure 32 comprises in broken line the lever arm of the force, which is exerted in the direction of the spring 112, acting on the fork 6. In other embodiments not illustrated, the repulsion is not mechanical in nature, but by nature magnetic and / or electrostatic between a head and a fork 6 preferably pivotally mounted about two pivot axes 5 and 9.

The head 2 and the fork 6 preferably follow motion axes, which are illustrated here with a particular embodiment where they are pivot axes. Indeed, the movements of the head 2 and the fork 6 are independent, and can in theory follow any kinematics, as long as compatible with the energy transfer between the escape wheel and the balance.

Unless otherwise specified, the remainder of the present description relates to a preferred embodiment of the invention, illustrated by the Figures 1 to 20 , where the anchor 1 has a bistable behavior, and comprises at least one bistable element, preferably at least one flexible blade 10. A flexible blade is a simple embodiment, we can give other shapes to the bistable element without departing from the invention.

The invention also relates to a watchmaking exhaust mechanism 100 comprising at least one plate 40 carrying an escape wheel 20 and a rocker 30 cooperating with the same anchor 1.

According to the invention, the head 2 and said fork 6 are assembled, directly or indirectly, to the plate 40 so that the flexible blade 10 is mounted in prestressing buckling between the head 2 and the fork 6, this anchor 1 constituting a bistable system comprising at least two stable states and two metastable states.

For the sake of clarity, the invention is described here in the particular case of a single flexible blade, mounted bistable, on Figures 1 to 20 . The Figures 30 and 31 illustrate an example with two flexible blades, other arrangements are naturally possible.

The only direct permanent mechanical connection between the head 2 and the fork 6 is here ensured by at least one flexible blade 10.

• par déplacement
• par application d'une force ou d'un couple
• par fabrication.

So that the anchor 1 behaves like a bistable element, this blade 10 is prestressed in the service position of the anchor 1. As will be seen in the following description, this prestressing can be achieved:

• by displacement
• by applying a force or a couple
• by manufacture.

The flexible blade 10 operates in buckling. The prestress is adjustable in the case of the application of a force or a couple.

Therefore, in an advantageous embodiment of the invention illustrated by the figures, the blade 10 has in the free state a different geometry of the shapes it can take when the anchor 1 is incorporated in a mechanism of exhaust 100 and fixed on a plate 40.

The anchor 1 comprises, for its attachment to a plate 40, first fastening means and / or guide carried by the head 2, and second fastening means and / or guide carried by the fork 6. Each of the two main components, head 2 and fork 6, may have mechanical links of conventional type, such as guidance in pivoting or translation, or have one or more fixed anchor points relative to the plate 40 and include flexible parts which give it a mobility relative to this plate, in pivoting and / or in translation, as described in the application WO2012010408 or in the application EP 2 455 821 same depositor, in a configuration that will be described later in this "virtual pivot".

In a particular embodiment represented on the Figures 1 to 20 and 30 and 31 , the anchor head 2 is movable with respect to a first pivot axis 5 or pivots about this first axis 5, and the fork 6 is movable with respect to a second pivot axis 9 or pivots about this second axis 9 . On the Figures 1 to 20 the second axis 9 is distinct from the first axis 5.

The particular achievement of Figures 1 to 20 is not limiting, and relates to a particular case where the head 2 is pivotally mounted about a first pivot axis 5. In this same particular embodiment, the fork 6 is pivotally mounted about a second pivot axis 9 of the first axis 5. In an embodiment, as illustrated where the head 2 and the fork 6 are substantially coplanar, these axes 5 and 9 are preferably distinct. Other examples which are not part of the claimed invention are possible, as in the case of Figures 30 and 31 which show a stepped variant, where the axes 5 and 9 are geometrically confused: the anchor 1 then comprises two bistable blades 10S and 10J, each having a first end 10ES, 10EJ, fixed to a plate not shown, and a second end 103S 103J recessed in respectively the fork 6 and the head 2. The head 2 and the fork 6 are partially superimposed and pivot about the same geometric axis of pivoting P, are connected by a return spring 104 in the form of a loop, hooked 104S in the range 6 and 104J in the head 2. This spring 104, which acts as a buffer spring, has a torque greater than that of the bistable.

The figure 37 illustrates another form of anchor with two flexible coplanar bistable blades with the head 2 and the fork 6.

Still other variants are feasible, for example with a substantially linear oscillating movement of the head 2 relative to the center line between the escape wheel 20 and the rocker 30, and a pivoting movement of the fork 6 around an axis 9.

In a particular embodiment also illustrated by the figures, the fork 6 carries a sting 7 with an anti-shock function to cooperate with a notch 34 of a plate 31 of the balance 30 and at least one horn 8, here two horns 8, to cooperate with an ankle 35 of this balance 30 for the pulse function.

The anchor 1 is articulated, that is to say that the head 2 and the fork 6 are movable relative to each other and indirectly connected to one another by at least one intermediate component, here a flexible blade 10, ensuring their relative mobility of movement.

This bistable element is preferably in the form of a recessed beam. In a particular embodiment illustrated by the figures this beam is embedded at its two ends; the distance between the two ends is less than the length of beam at rest, which allows to have two stable positions, and at least one metastable position. The calculation of the energy stored in the bistable element can be made according to the angles taken by the bistable blade 10 at its two ends; or, in the case of several bistable blades, angles that each of them has, at each of its ends, with one of the components of the anchor 1, head 2 or fork 6, or plate 40, or other intermediate component according to the case.

• ou bien au niveau d'un axe qui pivote librement ;
• ou bien dans la platine pour former un pivot flexible.

The ends of this beam can be, in particular, each, recessed:

• or at an axis that pivots freely;
• or in the platen to form a flexible pivot.

This at least one bistable element or flexible bistable blade 10 is mounted prestressed in buckling between the head 2 and the fork 6. And preferably the only direct mechanical link between the direct head 2 and the fork 6, that is to say except for their pivots or their fastenings to a plate 40 or similar, is provided by this at least one bistable blade 10.

In the version shown, the flexible blade 10 has a first end 11 secured angularly to the head 2 and disposed in close proximity to the first axis 5, and a second end 12 angularly secured to the fork 6 and disposed in close proximity to the second axis 9 .

It is understood here that the first axis 5 and the second axis 9 are here geometric axes around which the pivoting of the head 2 and the fork 6 is performed. These axes do not necessarily correspond to conventional physical pivots, they can also be correspond to flexible pivots or virtual pivots.

In the particular version similar to a Swiss anchor, illustrated by the figures, but in no way limiting, this anchor 1 carries an entry pallet 3 and an exit pallet 4. In a particular variant, the entry pallet 3 or / and the output pallet 4 has a projecting end 13, in the form of a tongue visible on the figure 34 , opposite the first axis 5 and having a flat surface 14 adapted to receive a point 22 of a tooth 21 of an escape wheel 20, as visible on the figure 34 .

Advantageously, the deflection, in particular the deflection angular pivoting in the case of Figures 1 to 20 , head 2 and that of the fork 6 are limited relative to each other by stops.

According to the invention, the head 2 comprises at least a first arm 15 having a first bearing and abutment surface 16 arranged to cooperate, in abutment or in abutment, in certain relative positions of the head 2 and the fork 6, with a second bearing and abutment surface 18 that comprises at least a second arm 17 that includes the fork 6.

These arms 15 and 17 allow a good clearance of the pallets to the pulse, while stopping sturdily the escape wheel at the end of the arming of the bistable element.

In the variant shown, the head 2 comprises two first arms 15A, 15B, with first surfaces 16A, 16B, cooperating with second surfaces 18A, 18B, second arms 17A, 17B, of the fork 6.

According to the invention, the anchor 1 is made integrally with this at least one flexible blade 10 or the bistable element: the head 2, the blade 10 and the fork 6 are a single component.

In this version, the anchor 1 is advantageously made of silicon or silicon oxide or metal glass (in particular obtained by a "LIGA" method). Indeed, the prestressing of the bistable element or the bistable blade 10, is very low, in particular close to 5 micrometers, and its adjustment is possible, but delicate, in case of manufacturing components assembled to each other.

By applying a preload of 8 μm between its ends to a blade of NiP flat spring produced by a "LIGA" process and with dimensions of 2.1 x 0.10 x 0.02 mm, with working angle ranges the two ends of -7 ° to + 7 ° (defined by the stops), the energy difference, between corrugated positions (with a maximum stress level close to 400 MPa) and positions in simple arc, concave or convex, corresponds to a passage between energy passes at 0.5 μJ and energy wells at 0.13 μJ. a difference of 0.37 μJ, which is comparable to the energy available at the escape wheel of the caliber ETA 2824-2 at each alternation. This dimension is therefore sufficient to provide a pulse of normal intensity.

In another particular embodiment, the anchor 1 comprises a first flexible pivot 61 and / or a second flexible pivot 62 constituting a flexible guide at respectively the first axis 5 and / or the second axis 9.

This first flexible pivot 61 or / and this second flexible pivot 62 may, again, be a virtual pivot. For example, the figure 39 gives an example of head 2, connected to the plate 40 by two blades 2S and 2J, and whose first flexible pivot coincides with the pivot axis 23 of the escape wheel 20.

The figure 18 shows an energy distribution diagram in the flexible blade 10 or the bistable element: in X and Y are represented the angles that make each of the two ends 101, 102, of the blade 10 with their points of attachment or of respective recesses 11, 12, on the anchor head 2 and on the fork 6.

In Z is represented a level of energy, graduated arbitrarily from 0 to 8. The figure 19 shows the projection on the XOY plane of this energy distribution layer, with the corresponding energy level curves.

This energy distribution is saddle-shaped, symmetrical with respect to a vertical plane PS oriented along the bisector of the axes OX and OY. A dorsal D of very high energy level (6 to 8) extends in this plane of symmetry PS. The dorsal D is delimited by two energy passes first CE1 and second CE2, which each extend between two slopes of steep slope between the dorsal D and low energy zones, called energy wells, corresponding to stable positions. first PS1 and second PS2 (hollow of the energy layer). In the extension of the dorsal D and beyond it, the energy passes CE1 and CE2 are each bordered by a high energy zone A1 and A2 respectively. These energy passes CE1 and CE2 correspond to two metastable positions.

The figure 19 shows that the flexible blade 10 can not take any position of energy on the T web: the extreme parts of the anchor 1, in this case the head 2 and the fork 6, have a travel which is limited, either by second limiting pins 41A and 41B for the fork 6, or by limiting the pivoting of the head 2 by the second arms 17A, 17B, of the fork 6. The bistable blade 10 always pushes these end portions, head 2 and fork 6, anchor 1, against these stops. Therefore, if one of these ends is fixed, and the other is free, we always move on the edges of the rectangle R, as schematized on the figure 20 , which summarizes the energy levels corresponding to each of the times described by the Figures 1 to 17 in a simplified way, the energy path being almost rectilinear, and the rectangle shape of the energy path being a good approximation. Thus the pivoting of the head 2 as that of the fork 6 is limited angularly by stops. In the particular case of the illustrated variant, the stops limiting the angular displacement of the head 2, respectively of the fork 6, are movable and constituted by surfaces of the fork 6, respectively of the head 2.

The limiting pins 41 are here represented on the plate. Note that they can take other positions, for example in the form of dishes under the teeth 21 of the escape wheel 20.

• après rechargement en énergie par la roue d'échappement 20 et pendant une phase transitoire, à haute énergie, d'approche du premier col d'énergie CE1, avec un profil ondulé en Z sur les figures, repère 54 ;
• après libération de l'énergie dont dispose la lame bistable 10, lors du passage du premier col d'énergie CE1, sous forme d'une impulsion donnée au balancier 30 dans le premier sens, par exemple sens anti-horaire, la lame 10 occupe une deuxième position stable PS2 à basse énergie, avec un profil en arc, dit convexe, repère 51.
• après rechargement en énergie par la roue d'échappement et pendant une phase transitoire, à haute énergie, d'approche du deuxième col d'énergie CE2, avec un profil ondulé en S sur les figures, repère 53 ;
• après libération de l'énergie dont dispose la lame 10, lors du passage du deuxième col d'énergie CE2, sous forme d'une impulsion donnée au balancier 30 dans le deuxième sens, par exemple horaire, la lame 10 occupe une première position stable PS1 à basse énergie, avec un profil en arc, dit concave, repère 52.

In the example illustrated by the figures, the anchor 1 thus performs a closed cycle during which the flexible blade 10 successively occupies four main configurations:

• after reloading energy by the escape wheel 20 and during a transient phase, at high energy, approaching the first energy pass CE1, with a Z-shaped corrugated profile in the figures, reference 54;
• after release of the energy available to the bistable blade 10, during the passage of the first energy pass CE1, in the form of a pulse given to the rocker 30 in the first direction, for example anti-clockwise, the blade 10 occupies a second stable position PS2 at low energy, with an arcuate profile, said convex, reference 51.
• after reloading energy by the escape wheel and during a transient phase, at high energy, approaching the second energy pass CE2, with an S-shaped corrugation in the figures, mark 53;
• after release of the energy available to the blade 10, during the passage of the second energy pass CE2, in the form of a pulse given to the rocker 30 in the second direction, for example hourly, the blade 10 occupies a first stable position PS1 low energy, with a profile arc, said concave, mark 52.

Naturally, the shape of the prestressed beam constituted by the bistable blade 10 is a non-limiting example. The concave, convex, S, Z geometries that the plate 10 can occupy are specific to the case in point. It is also possible to use a more complex geometry in the state of stable rest, for example in S or Z.

The preferred choice to traverse a rectangle R, rather than a square, is explained by the objective of stopping before the energy pass, when the bistable blade 10 is rearmed. In fact, if one s' stopped precisely on the energy collar in unstable position, the risk would be that with a very small shock, the bistable blade 10 can tilt and, the sting 7 would then be blocked by the balance plate and rub against him permanently, this which is bad for walking and alters the performance. Also, preferably, the stops are arranged so as to stop the bistable blade 10 before the first CE1 or the second CE2 energy col, during arming by energy charging of this bistable blade 10.

Stops limiting the angular deflection of the head 2, respectively of the fork 6, are advantageously mobile and constituted by surfaces of the fork 6, respectively of the head 2.

In the figures, the angular displacement of the head 2 is limited by stops formed by two second arms 17A, 17B that includes the fork 6.

The surfaces 18A, 18B form abutments equivalent to a non-drawing rest stop. Preferably, as visible on the figure 1 they have an arcuate profile A centered on the second pivot axis 9, so that, when the pin 35 of the rocker 30 begins to drive the fork 6 (time T2 to time T3 below), the head 2 does not turn, there is only the friction to overcome.

• la roue d'échappement 20 est immobile, sa dent 21A en appui sur la palette d'entrée 3 de la tête d'ancre 2 ;
• la tête d'ancre 2 est immobile, son premier bras 15B est arrêté au niveau de sa pointe 16B par la deuxième surface d'appui 18B du deuxième bras 17B de la fourchette 6 ; ce mode de blocage illustré sur les figures n'est pas limitatif, il présente l'avantage d'un encombrement réduit et d'une simplicité de réalisation ;
• la lame bistable 10 est en forme de Z, repère 54, proche du col d'énergie CE1 ;
• la fourchette 6 est immobile, sa surface de butée 19A est en appui de butée sur la goupille de limitation 41A correspondante ;
• arc libre du balancier : le balancier 30 pivote dans le premier sens, par exemple sens anti-horaire, sa cheville 35 est en position à 11 heures.

Each cycle time bears the number of the corresponding figure. In the first time T1 of the figure 1 :

• the escape wheel 20 is stationary, its tooth 21A resting on the entry pallet 3 of the anchor head 2;
• the anchor head 2 is stationary, its first arm 15B is stopped at its tip 16B by the second bearing surface 18B of the second arm 17B of the fork 6; this blocking mode illustrated in the figures is not limiting, it has the advantage of a small footprint and simplicity of implementation;
• the bistable blade 10 is Z-shaped, mark 54, close to the energy collar CE1;
• the fork 6 is stationary, its abutment surface 19A abuts against the corresponding limiting pin 41A;
• free arm of the pendulum: the rocker arm 30 pivots in the first direction, for example counterclockwise, its peg 35 is in position at 11 o'clock.

• la roue 20 reste immobile;
• la tête 2 reste immobile;
• la lame 10 est en forme de Z, repère 54, proche du col d'énergie CE1 ;
• la fourchette 6 reste immobile, en appui sur la goupille 41A ;
• le balancier 30 pivote dans le premier sens, sa cheville 35 en position à 10 heures appuie sur la surface intérieure 81 B de la corne 8B, le balancier 30 commence ainsi à dégager la fourchette 6.

In T2:

• the wheel 20 remains motionless;
• head 2 remains motionless;
• the blade 10 is Z-shaped, mark 54, close to the energy collar CE1;
• the fork 6 remains stationary, resting on the pin 41A;
• the rocker 30 pivots in the first direction, its peg 35 in position at 10 hours presses on the inner surface 81 B of the horn 8B, the rocker 30 thus begins to release the fork 6.

• la roue 20 reste immobile;
• la tête 2 est immobile, son premier bras 15B arrêté par le deuxième bras 17B, qui amorce son dégagement, pour permettre la libération de la tête 2 au temps suivant ; là encore, des solutions alternatives sont possibles, sans s'écarter de l'esprit de l'invention ;
• la lame 10 est en forme de Z, repère 54, et commence le passage du col d'énergie CE1 ;
• la fourchette 6 pivote en deuxième sens, par exemple horaire, sa surface de butée 19A a quitté la goupille 41A, son deuxième bras 17B est à la limite de quitter le premier bras 15B;
• le balancier 30 pivote dans le premier sens, sa cheville 35 en position à 9 heures 30 appuie sur la surface intérieure 81 B de la corne 8B, le balancier 30 dégage la fourchette 6.

In T3:

• the wheel 20 remains motionless;
• the head 2 is stationary, its first arm 15B stopped by the second arm 17B, which initiates its release, to allow the release of the head 2 at the next time; here again, alternative solutions are possible, without departing from the spirit of the invention;
• the blade 10 is Z-shaped, mark 54, and begins the passage of the energy pass CE1;
• the fork 6 pivots in the second direction, for example hourly, its abutment surface 19A has left the pin 41A, its second arm 17B is at the limit of leaving the first arm 15B;
• the rocker 30 pivots in the first direction, its peg 35 in position at 9 o'clock presses on the inner surface 81 B of the horn 8B, the rocker 30 disengages the fork 6.

• la roue 20 est libre, elle reste encore momentanément presque immobile à cause de son inertie ;
• la tête 2 est libre, à part la liaison avec la lame 10 ;
• la lame 10 passe le col d'énergie CE1, se détend et passe en forme convexe 51 ;
• la fourchette 6 pivote en deuxième sens, par exemple horaire, libère la tête 2, la surface intérieure 81A de sa corne 8A entraîne la cheville 35 dans le premier sens, c'est l'impulsion ;
• le balancier 30 pivote dans le premier sens, sa cheville 35 en position à 9 heures entraînée par la corne 8A.

T4 is a driving time, where the blade 10 passes the energy pass CE1, and gives its impulse in the first direction, the pendulum 30:

• wheel 20 is free, it remains momentarily almost immobile because of its inertia;
• the head 2 is free, apart from the connection with the blade 10;
• the blade 10 passes the CE1 energy collar, relaxes and passes in convex form 51;
• the fork 6 pivots in the second direction, for example hourly, releases the head 2, the inner surface 81A of its horn 8A drives the pin 35 in the first direction is the pulse;
• the rocker 30 pivots in the first direction, its peg 35 in position at 9 o'clock driven by the horn 8A.

• la roue 20 est libre, elle reste encore momentanément presque immobile à cause de son inertie ;
• la tête 2 est libre;
• la lame 10 arrive dans une position stable PS2 de basse énergie, en forme convexe 51 ;
• la fourchette 6 pivote en deuxième sens, par exemple horaire, la surface intérieure 81A de sa corne 8A perd le contact avec la cheville 35, c'est la fin de la phase d'impulsion ;
• le balancier 30 pivote dans le premier sens, la cheville 35 en position à 8 heures perd le contact avec la corne 8A.

In T5, it is the end of the impulse given to the balance 30 by the fork 6, which comes into abutment on its limiting pin 41 B:

• wheel 20 is free, it remains momentarily almost immobile because of its inertia;
• head 2 is free;
• the blade 10 arrives in a stable position PS2 of low energy, in convex form 51;
• the fork 6 pivots in the second direction, for example hourly, the inner surface 81A of its horn 8A loses contact with the pin 35 is the end of the pulse phase;
• the rocker 30 pivots in the first direction, the pin 35 in position at 8 o'clock loses contact with the horn 8A.

• la roue 20 va commencer à pivoter dans le premier sens;
• la tête 2 est libre;
• la lame 10 est dans une position stable PS2 de basse énergie, en forme convexe 51 ;
• la fourchette 6 est immobile, sa surface de butée 19B en appui sur la goupille 41 B ;
• le balancier 30 pivote dans le premier sens, sa cheville 35 en position à 6 heures 30 sous l'effet de l'impulsion.

In T6, only pivots the pendulum 30 which runs through the free arc:

• the wheel 20 will begin to pivot in the first direction;
• head 2 is free;
• the blade 10 is in a stable position PS2 of low energy, in convex form 51;
• the fork 6 is stationary, its abutment surface 19B resting on the pin 41 B;
• the rocker 30 pivots in the first direction, its pin 35 in position at 6:30 under the effect of the pulse.

• la roue 20 pivote dans le premier sens;
• la tête 2 pivote dans le premier sens;
• la lame 10 se plie ou se déplie légèrement, en raison de la rotation ;
• la fourchette 6 reste immobile, en appui sur la goupille 41 B ;
• le balancier 30 pivote dans le premier sens, sa cheville 35 atteint une position à 6 heures sous l'effet de l'impulsion.

In T7 takes place the release of the escape wheel 20 by the head 2:

• the wheel 20 pivots in the first direction;
• the head 2 pivots in the first direction;
• the blade 10 bends or unfolds slightly, due to rotation;
• the fork 6 remains stationary, resting on the pin 41 B;
• the rocker 30 pivots in the first direction, its pin 35 reaches a position at 6 o'clock under the effect of the pulse.

First limiting pins 48A, 48B are advantageously implanted near the head 2, as safeties in case of shocks or dynamic effects: for example, during the passage of time 6 to time 7, where the head 2 pivots in the second sense, for example, hourly: if it acquires too much speed, it may go too far, while in time 8 it must start in the other direction.

• la roue d'échappement 20 pivote dans le premier sens, jusqu'à la butée d'une dent 21 B en appui sur la palette dé sortie 4 ;
• la tête 2 est libre et momentanément immobile ;
• la lame 10 reste en position stable PS2, en forme convexe 51 ;
• la fourchette 6 reste immobile, en appui sur la goupille 41 B ;
• le balancier 30 est mobile, il continue sa course (sa cheville 35 en position à 6 heures).

At T 8 the escape wheel 20 reaches another pallet 4 of the anchor 1. The fall, that is to say the angle traveled by the escape wheel 20 between the times T7 and T8 "in the For example, the term "empty" may be too important for a conventional wheel as shown here for the understanding of the invention, it is useful to optimize the geometry of the teeth 21 of the wheel 20, and pallets 3 and 4 of the head 2 to decrease this fall;

• the escape wheel 20 pivots in the first direction, until the stop of a tooth 21 B resting on the output pallet 4;
• head 2 is free and momentarily motionless;
• the blade 10 remains in a stable position PS2, in convex shape 51;
• the fork 6 remains stationary, resting on the pin 41 B;
• the balance 30 is movable, it continues its course (its peg 35 in position at 6 o'clock).

• la roue 20 pivote dans le premier sens, en appui sur la palette 4, et entraîne en pivotement la tête 2 ;
• la tête 2 pivote dans le deuxième sens, par exemple horaire, et vient en appui, son premier bras 15A est arrêté au niveau de sa pointe 16A par la deuxième surface d'appui 18A du deuxième bras 17A de la fourchette 6, et, une fois elle-même en arrêt, bloque ainsi la roue 20 ;
• la lame 10, réarmée par la roue d'échappement par l'intermédiaire de la tête 2, passe en position ondulée en S 53, au voisinage immédiat du col d'énergie CE2 ;
• la fourchette 6 reste immobile, en appui sur la goupille 41 B, l'armage du bistable est achevé, c'est la prise de repos ;
• le balancier 30 est mobile (il effectue une alternance jusqu'au temps suivant T10), (sa cheville 35 en position à 6 heures).

In T9, the energy provided by the escape wheel 20 allows the arming by recharging the energy of the bistable blade 10, which is close to the energy pass following CE2:

• the wheel 20 pivots in the first direction, resting on the pallet 4, and pivots the head 2;
• the head 2 pivots in the second direction, for example hourly, and comes to bear, its first arm 15A is stopped at its tip 16A by the second bearing surface 18A of the second arm 17A of the fork 6, and, a once itself in stop, thus blocks the wheel 20;
• the blade 10, rearmed by the escape wheel via the head 2, goes into a wavy position at S 53, in the immediate vicinity of the energy collar CE2;
• the fork 6 remains stationary, resting on the pin 41 B, the arming of the bistable is completed, it is the taking of rest;
• the rocker 30 is movable (it alternates until the next time T10) (its ankle 35 in position at 6 o'clock).

• la roue 20 est immobile, sa dent 21 B en appui sur la palette 4;
• la tête 2 est immobile en appui, par son premier bras 15A sur le deuxième bras 17A de la fourchette 6, et, une fois elle-même en arrêt, bloque ainsi la roue 20;
• la lame 10 est position ondulée en S en forme 53, au voisinage immédiat du col d'énergie CE2 ;
• la fourchette 6 reste immobile, en appui sur la goupille 41 B ;
• le balancier 30 pivote dans le deuxième sens, sa cheville 35 en position à 8 heures arrive en appui sur la face interne 81A de la corne 8A, pour commencer à dégager la fourchette 6.

In T10 begins the return of the balance 30 in the following alternation:

• the wheel 20 is stationary, its tooth 21 B resting on the pallet 4;
• the head 2 is stationary bearing, by its first arm 15A on the second arm 17A of the fork 6, and once itself stopped, thus blocks the wheel 20;
• the blade 10 is wavy position S-shaped 53, in the immediate vicinity of the CE2 energy collar;
• the fork 6 remains stationary, resting on the pin 41 B;
• the rocker 30 pivots in the second direction, its peg 35 in position at 8 o'clock comes to rest on the inner face 81A of the horn 8A, to start to release the fork 6.

• la roue 20 est immobile, en appui sur la palette 4;
• la tête 2 est immobile en appui sur le deuxième bras 17A;
• la lame 10 est position ondulée en S en forme 53, prête à passer le col d'énergie CE2 ; le bistable devient menant, et effectue le rattrapage du jeu dès le passage du col d'énergie ;
• la fourchette 6 pivote dans le premier sens, et atteint la position où elle va libérer la tête 2 ;
• le balancier 30 pivote dans le deuxième sens, sa cheville 35 en position à 9 heures et en appui sur la face interne 81A de la corne 8A, et dégage la fourchette 6.

In T11 the rocker arm 30 releases the fork 6, which will itself release the head 2:

• the wheel 20 is stationary, resting on the pallet 4;
• the head 2 is stationary bearing on the second arm 17A;
• the blade 10 is wavy position S-shaped 53, ready to pass the CE2 energy collar; the bistable becomes leading, and makes the catch of the game as soon as the pass of the energy pass;
• the fork 6 pivots in the first direction, and reaches the position where it will release the head 2;
• the rocker 30 pivots in the second direction, its peg 35 in position at 9 o'clock and resting on the inner face 81A of the horn 8A, and disengages the fork 6.

• la roue 20 est libre, encore momentanément presque immobile à cause de son inertie ;
• la tête 2 est libre, à part la liaison avec la lame 10 ;
• la lame 10 passe le col d'énergie CE2, se détend et passe en forme concave 52;
• la fourchette 6 pivote en premier sens, libère la tête 2, la surface intérieure 81 B de sa corne 8B entraîne la cheville 35 dans le deuxième sens, par exemple horaire, c'est l'impulsion ;
• le balancier 30 pivote dans le deuxième sens, sa cheville 35 en position à 9 heures 30 entraînée par la surface intérieure 81 B de la corne 8B..

In T12, the blade 10 passes through the energy collar CE2, and gives a pulse in the second direction, to the balance 30, symmetrically to T4:

• the wheel 20 is free, still momentarily almost immobile because of its inertia;
• the head 2 is free, apart from the connection with the blade 10;
• the blade 10 passes the CE2 energy collar, relaxes and passes in concave form 52;
• the fork 6 pivots in the first direction, releases the head 2, the inner surface 81 B of its horn 8B drives the pin 35 in the second direction, for example hourly, it is the pulse;
• the rocker arm 30 pivots in the second direction, its peg 35 in position at 9 o'clock driven by the inner surface 81 B of the horn 8B.

• la roue 20 est libre, encore momentanément presque immobile à cause de son inertie;
• la tête 2 est libre;
• la lame 10 est en forme concave 52, en position stable PS1 à faible énergie;
• la fourchette 6 pivote en premier sens, sa corne 8B entraîne la cheville 35 dans le deuxième sens, par exemple horaire, et sa surface de butée 19A vient en appui sur la goupille 41 A ;
• le balancier 30 pivote dans le deuxième sens, , sa cheville 35 en position à 10 heures 30 entraînée par la surface intérieure 81 B de la corne 8B.

At T13 the pulse ends, and the fork 6 arrives at the stop position:

• the wheel 20 is free, still momentarily almost immobile because of its inertia;
• head 2 is free;
• the blade 10 is in concave form 52, in stable position PS1 at low energy;
• the fork 6 pivots in the first direction, its horn 8B drives the pin 35 in the second direction, for example hourly, and its abutment surface 19A bears on the pin 41 A;
• the rocker 30 pivots in the second direction, its pin 35 in position at 10 o'clock 30 driven by the inner surface 81 B of the horn 8B.

• la roue 20 est libre, encore momentanément presque immobile à cause de son inertie, et va commencer à pivoter;
• la tête 2 est libre;
• la lame 10 est en forme concave 52, en position stable PS1 à faible énergie;
• la fourchette 6 est immobile en appui sur la goupille 41A ;
• le balancier 30 pivote dans le deuxième sens, sa cheville 35 en position à 11 heures.

In T14, similarly to T6, the pendulum 30 traverses the free arc, this time in the second direction:

• the wheel 20 is free, still momentarily almost immobile because of its inertia, and will start to rotate;
• head 2 is free;
• the blade 10 is in concave form 52, in stable position PS1 at low energy;
• the fork 6 is stationary bearing on the pin 41A;
• the rocker arm 30 pivots in the second direction, its peg 35 in position at 11 o'clock.

• la roue 20 pivote en premier sens;
• la tête 2 pivote en deuxième sens, et la palette 3 vient sur la trajectoire des dents de la roue 20 ;
• la lame 10 est en forme concave 52, en position stable PS1 à faible énergie;
• la fourchette 6 reste immobile en appui sur la goupille 41A ;
• le balancier 30 est mobile (sa cheville 35 en position à 11 heures).

In T15, similarly to T7, the wheel 20 passes the pallet 4:

• the wheel 20 pivots in the first direction;
• the head 2 pivots in the second direction, and the pallet 3 comes on the path of the teeth of the wheel 20;
• the blade 10 is in concave form 52, in stable position PS1 at low energy;
• the fork 6 remains stationary bearing on the pin 41A;
• the rocker 30 is movable (its peg 35 in position at 11 o'clock).

• la roue 20 pivote en premier sens, et une dent 21C vient en appui sur la palette 3;
• la tête 2 est libre et immobile ;
• la lame 10 est en forme concave 52, en position stable PS1 à faible énergie;
• la fourchette 6 reste immobile en appui sur la goupille 41 A ;
• le balancier 30 est mobile (sa cheville 35 en position à 11 heures).

In T16, similarly to T8, the escape wheel 20 reaches pallet 3:

• the wheel 20 pivots in the first direction, and a tooth 21C bears on the pallet 3;
• head 2 is free and motionless;
• the blade 10 is in concave form 52, in stable position PS1 at low energy;
• the fork 6 remains stationary bearing on the pin 41 A;
• the rocker 30 is movable (its peg 35 in position at 11 o'clock).

• la roue 20 pivote en premier sens, en appui sur la palette 3, et entraîne la tête 2 en pivotement;
• la tête 2 pivote en premier sens, et réarme la lame 10 ;
• la lame 10 est en forme ondulée de Z, repère 54 en approche du premier col d'énergie CE1;
• la fourchette 6 reste immobile en appui sur la goupille 41A ;
• le balancier 30 est mobile ( sa cheville 35 en position à 11 heures).

The time T17 ends the cycle, before the return to the time T1, similarly to the time T9, the energy provided by the wheel 20 allows the arming by the energy reloading of the blade 10, which is close to the neck of following energy CE1:

• the wheel 20 pivots in the first direction, resting on the pallet 3, and causes the head 2 to pivot;
• the head 2 pivots in the first direction, and resets the blade 10;
• the blade 10 is in corrugated shape of Z, 54 on the approach of the first energy collar CE1;
• the fork 6 remains stationary bearing on the pin 41A;
• the rocker 30 is movable (its peg 35 in position at 11 o'clock).

The two phases "pulse of the bistable blade 10 on the balance 30" and "arming of the bistable blade 10 by the escape wheel 20" are completely dissociated in the figures, to simplify the description of the successive phases of the cycle. In reality, the two phases overlap in part over time, but relatively little if the inertia of the escape wheel is high.

• la durée entre les temps 2 et 5 (impulsion de l'élément bistable) est très courte, donnée par la vitesse du balancier 30, notamment voisine de 7 ms pour 300° d'amplitude à 4Hz et 50° d'angle de levée ;
• la durée entre les temps 7 et 9 (réarmage de la lame bistable 10) peut être longue, jusqu'à environ 120 ms si l'inertie de la roue d'échappement 20 est élevée (environ une alternance).

Typically:

• the duration between the times 2 and 5 (pulse of the bistable element) is very short, given by the speed of the balance 30, in particular close to 7 ms for 300 ° amplitude at 4 Hz and 50 ° of lifting angle;
• the time between times 7 and 9 (rearming of the bistable blade 10) can be long, up to about 120 ms if the inertia of the escape wheel 20 is high (about one half cycle).

So that the energy transmitted to the balance is always the same, it is preferable that the arming of the bistable blade 10 is done slowly, so that the inertia of the escape wheel. (or the rest of the gear) is high.

It is noted that an achievement according to the Figures 30 and 31 with two superimposed bistable blades 10S and 10J allows, by adjusting the stiffness of the return spring 104 between the head 2 and the fork 6, to obtain a similar energy distribution, with two energy wells separated by a dorsal.

Preferably the escape mechanism 100 comprises at least one plate 40 carrying an escape wheel 20 and at least one rocker 30 cooperating with the same anchor 1. The plate 40 has limiting pins 41 (41A, 41B in the figures) around the fork 6 in the vicinity of a plate 31 of the balance 30.

• d'une part au niveau du premier axe 5, ou bien par un premier arbre de pivotement 63 quand le guidage de l'ancre 1 y est classique par pivot et palier, ou bien par une première liaison fixe 65 quand l'ancre 1 y comporte un guidage flexible avec un premier pivot flexible 61,
• et d'autre part au niveau du deuxième axe 9, ou bien un deuxième arbre de pivotement 64 quand le guidage de l'ancre 1 y est classique par pivot et palier, ou bien par une deuxième liaison fixe 66 quand l'ancre 1 y comporte un guidage flexible avec un deuxième pivot flexible 62.

According to the invention, the anchor 1 is connected to the plate:

• firstly at the first axis 5, or by a first pivot shaft 63 when the guide of the anchor 1 is conventional pivot and bearing, or by a first fixed connection 65 when the anchor 1 y has a flexible guide with a first flexible pivot 61,
• and secondly at the second axis 9, or a second pivot shaft 64 when the guide of the anchor 1 is conventional pivot and bearing, or by a second fixed connection 66 when the anchor 1 y has a flexible guide with a second flexible pivot 62.

• d'une part une première pierre 42 ou un premier axe 43 ou un premier guidage flexible en position fixe pour le guidage en pivotement de la tête 2 ;,
• et d'autre part une deuxième pierre 44 ou un deuxième axe 45 ou un deuxième guidage flexible pour le guidage en pivotement respectivement de la fourchette 6.

The plate 40 comprises:

• on the one hand a first stone 42 or a first axis 43 or a first flexible guide in fixed position for the pivotal guidance of the head 2;
• and secondly a second stone 44 or a second axis 45 or a second flexible guide for the pivotal guidance respectively of the fork 6.

As visible on the figure 35 in a first variant A, the second stone 44 or the second axis 45 is at a fixed distance, and in a fixed position in a particular embodiment, with respect to the first stone 42 or the first axis 43. In a second variant B the second stone 44 or the second axis 45 is movable, in particular guided in translation in a particular embodiment, in a variable position relative to the plate 40, and is subjected to the action of second resilient biasing means 47. Naturally one can also have the reverse configuration where the first stone 42 or the first axis 43 is movable in this way. In a third variant C, the plate 40 comprises, on the one hand a first stone 42 or a first axis 43 which is movable, in particular guided in translation in a particular embodiment, in a variable position relative to the plate 40 and is subject to the action of first elastic return means 46, for the pivotal guidance of the head 2, and secondly a second stone 44 or a second axis 45 which is movable, in particular guided in translation in a particular embodiment, in a variable position relative to the plate 40 and is subjected to the action of second elastic return means 47, for the pivotal guidance of the fork 6. Again, the reverse configuration is feasible.

Preferably, in these different variants, the pivot axis 23 of the escape wheel 20, the pivot axis 32 of the rocker 30, the first stone 42 or respectively the first axis 43, the second stone 44 or respectively the second axis 45, are aligned. The figure 36 illustrates another configuration where the fork 6 is movable apart from the wheel-wheel alignment, and where the flexible blade 10 is deformed around an average position which is, for example and without limitation, a rope or an arc of a circle centered on the balance shaft; this configuration makes it possible to modify an existing movement comprising a usual aligned pointing, the axis usually serving a Swiss anchor becoming the axis 5 of the head 2.

In a particular embodiment of the invention, the bistable anchor 1 is pre-mounted in a cassette, and the flexible blade 10 is already preloaded beforehand in this cassette. The cassette includes a centering means and / or fixing on a plate. Advantageously this cassette comprises a centering means which is arranged to cooperate with the pivot usually provided for the Swiss anchor on an existing movement. Depending on the case, the cassette remains pivotable around this pivot, or is immobilized in position relative to the carrier plate of this pivot. Such a cassette assembly has the advantage of making unnecessary the presence of a bridge above the anchor. The cassette may, again, be provided with a micrometric adjustment system in position. The cassette can still incorporate a suspended shockproof.

The figure 38 illustrates two variants of embedding the bistable flexible blade 10 in the head 2 and the anchor fork 6, the first where the blade 10 is substantially in alignment with the pivot axes 5 and 9 but where its ends are distant from these axes, and the second where the assembly is asymmetrical, to favor one of the impulses, creating a deeper energy well.

The invention also relates to a watch movement 200 comprising at least one such escape mechanism 100.

The invention also relates to a timepiece 300 comprising at least one watch movement 200, or / and at least one such exhaust mechanism 100.

Naturally, the flexible blade 10 is one way among others of making a bistable between two halves of anchor, which is not limiting.

Similarly, the locking of the head 2 of the anchor 1 at the end of the arming of the bistable element, and the release of this head 2 at the end of the pulse given to the rocker 30, can be made according to other embodiments, without departing from the present invention.

Yet another variant of the invention is to mount the fork 6 directly integral with the bistable element, or the bistable blade 10 as the case may be, and not to pivot this fork 6 by allowing it an angular deflection of any center, but by limiting the stroke of this fork 6 relative to the first pivot axis 5 of the head 2, by a limiting element 71, so that the bistable element, or the bistable blade 10, which ensures only the pivoting of the fork 6 relative to the balance 30, remains under prestressing throughout its range of use. As visible on the Figures 25 and 26 which illustrate examples which are not part of the claimed invention, this limiting element 71 is integral with the head 2 or integral with a plate 40 (in relief as on the figure 26 or hollow) on which the anchor 1 is fixed, and cooperates with a complementary limiting element 72 that includes the fork 6. Advantageously, the element 71 has the shape of a vee, and the element 72 is a pin or a pin. Pawns 49 limit the travel of the fork 6.

The figure 27 represents a variant where the prestress is made by a spring 73, fixed to a fixed element 74 of the plate 40, this spring 73 limiting the stroke of the fork 6 and ensuring the prestressing of the blade 10.

The Figures 23 and 24 illustrate two particular configurations of pivot axes with respect to a plate 40 carrying the escape mechanism: in figure 23 a first axis 5 and a second pivot axis 9 in fixed positions with respect to the plate 40, and figure 24 the second axis 9 in the mobile position, here in translation, and conjugated with an elastic return means 46.

The figure 29 groups together different models of pivots that can be used in particular for these variants: conventional pivot 91 alone, flexible pivot 92 alone, combination of a conventional pivot 91 and a guide 93 (particularly linear guide) of a certain rigidity, combination of a pivot flexible 92 and a guide (including linear guide) of a certain rigidity. In the latter two cases the displacement Δd, which induces prestressing, can be performed with a screw, an eccentric, a shim, or the like. This prestressing acts in particular on the spring elements of the guide 93 or the flexible pivot 92. These different types of pivots can of course be combined with each other.

A flexible anchor according to the invention can be used in other types of exhaust, in particular in that described by the document EP 1 967 919 in the name of ETA, as well as in the documents of the prior art cited in the same document EP 1 967 919 .

In short, the invention provides a very good control of the pulse, thanks to the use of a constant-force mechanism, comprising a bistable element, which alone delivers energy to the balance, with a regular intensity .

The energies in play are well decoupled in the different parts of the mechanism.

The mechanism according to the invention makes it possible to achieve high operational safety.

The invention is easily adapted to the incorporation of anti-shock means, it is for example possible to incorporate anti-shock abutments in the form of branches of the first arms 15 of the head 2, close to the bearing surfaces or stop 16, or the like.

The decoupling between the components of the exhaust mechanism according to the invention makes it possible, during the pulse, to accelerate only the fork, and not the entire mechanism.

• de réguler l'intensité de l'impulsion appliquée au balancier, le couple est constant ;
• de réduire les inerties en mouvement pendant l'oscillation ;
• d'effectuer la prise de repos en l'absence de tout tirage sur la roue.

The invention thus makes it possible:

• to regulate the intensity of the pulse applied to the balance, the torque is constant;
• to reduce the inertia in motion during the oscillation;
• to perform the rest stop in the absence of any draw on the wheel.

Claims (22)

1. Pallet lever (1) for a timepiece escapement, comprising a pallet head (2) carrying at least one entry pallet (3) and/or one exit pallet (4) and arranged to cooperate with an escape wheel (20), and further including a fork (6) arranged to cooperate with a balance (30), wherein the angular position of said fork (6) is variable relative to said head (2), and wherein the only direct, permanent, mechanical connection between said head (2) and said fork (6) is provided by at least one flexible strip (10), wherein the range of pivoting motion of said head (2) and that of said fork (6) are limited with respect to each other by stops, and wherein said head (2) includes at least a first arm (15) including a first support and stop surface (16) arranged to cooperate, in abutment or support, in certain relative positions of said head (2) and of said fork (6), with a second support and stop surface (18) comprised in at least a second arm (17) of said fork. (6), characterized in that the lever is made in one-piece with said at least one flexible strip (10)..
2. Pallet lever (1) according to claim 1, characterized in that the pallet lever includes, for attachment to a main plate (40), first securing and/or guide means carried by said head (2) and second securing and/or guide means carried by said fork (6).
3. Pallet lever (1) according to claim 2, characterized in that said pallet head (2) is mobile relative to a first pivot axis (5) or pivots about said first pivot axis (5) and in that said fork (6) is mobile relative to a second pivot axis (9) or pivots about said second pivot axis (9) which is distinct from said first axis (5).
4. Pallet lever (1) according to any of claims 1 to 3, characterized in that said pallet lever is made of silicon or silicon oxide or metallic glass.
5. Pallet lever (1) according to claim 3, characterized in that said pallet lever comprises a first flexible or virtual pivot (61) and/or a second flexible or virtual pivot (62) forming a flexible guide member respectively on said first axis (5) and/or said second axis (9).
6. Pallet lever (1) according to any claims 1 to 5, characterized in that said fork (6) includes a guard pin (7) and horns (8) for cooperation with a balance (30).
7. Pallet lever (1) according to any of claims 1 to 6, characterized in that a repulsive interaction between said head (2) and said fork (6) is achieved in a magnetic and/or electrostatic manner.
8. Pallet lever (1) according to any claims 1 to 7, characterized in that said pallet lever (1) is bistable and is pre-assembled in a cassette in which said at least one flexible strip (10) is already placed, prestressed, said cassette comprising a means for centring and/or securing on a plate.
9. Timepiece escapement mechanism (100), comprising at least one main plate (40) carrying an escape wheel (20) and a balance (30) cooperating with a same said pallet lever (1) according to any of claims 1 to 8, characterized in that said head (2) and said fork (6) are assembled to said plate (40) so that said at least one flexible strip (10) is mounted prestressed buckled between said head (2) and said fork (6),said pallet lever (1) forming a bistable system comprising at least two stable states and two metastable states.
10. Mechanism (100) according to claim 9, characterized in that said pallet lever (1) is arranged to perform a closed cycle during which said at least one flexible strip (10) which is a bistable strip, successively occupies four main configurations:

    - after being recharged with energy by said escape wheel (20) and during a transitional, high energy phase approaching a first energy pass (CE1), with a wavy Z-shaped profile (54);

    - after the energy available to said bistable strip (10) is released, passing over said first energy pass (CE1), in the form of an impulse imparted to said balance (30) in a first direction, said strip (10) occupies a second, stable, low energy position (PS2), with a convex arc profile (51);

    - after being recharged with energy by said escape wheel (20) and during a transitional, high energy phase approaching a second energy pass (CE2), with a wavy S-shaped profile (53);

    - after the energy available to said bistable strip (10) is released, passing over said second energy pass (CE2), in the form of an impulse imparted to the balance (30) in a second direction opposite to said first direction, said strip (10) occupies a first, stable, low energy position (PS1), with a concave arc profile (52).
11. Mechanism (100) according to claim 10, characterized in that said mechanism includes stops arranged to stop said bistable strip (10) before said first (CE1) or second (CE2) energy pass, when said bistable strip (10) is strung and recharged with energy.
12. Mechanism (100) according to claim 11, characterized in that stops limiting the angular motion of said head (2), respectively of said fork (6) are mobile and formed by said support and stop surfaces (16; 18) of said fork (6), respectively of said head (2).
13. Mechanism (100) according to claim 12, characterized in that the angular motion of said head (2) is limited by stops formed by two second arms (17A; 17B) comprised in said fork (6).
14. Mechanism (100) according to any of claims 9 to 13, characterized in that said flexible bistable strip (10) alone ensures the pivoting of said fork (6) relative to said balance (30), and in that the travel of said fork (6) relative to a first pivot axis (5) about which said head (2) pivots is limited by a banking element (71) integral with said head (2) or said plate (40) so that said bistable strip (10) remains prestressed throughout the entire operating range thereof.
15. Mechanism (100) according to any of claims 9 to 14, characterized in that said plate (40) includes banking pins (41) in proximity to a roller (31) of said balance (30), and in that said pallet lever (1) is connected to said plate, on the one hand, on a first pivot axis (5) about which said head (2) pivots, either by a first pivot arbor (63) when said head (2) is guided in a conventional manner by a pivot and bearing, or by a first fixed connection (65) when said head (2) includes a flexible guide member with a first flexible pivot (61), and on the other hand, on a second axis (9) about which said fork (6) pivots, either by a second pivot arbor (64) when said fork (6) is guided in a conventional manner by a pivot and bearing, or by a second fixed connection (66) when said fork (6) includes a flexible guide member with a second flexible pivot (62).
16. Mechanism (100) according to claim 15, characterized in that said plate (40) includes, on the one hand, a first jewel (42) or a first arbor (43) in a fixed position for pivotally guiding said head (2) or said fork (6), and on the other hand, a second jewel (44) or a second arbor (45) for pivotally guiding respectively said fork (6) or said head (2).
17. Mechanism (100) according to claim 15, characterized in that said second jewel (44) or said second arbor (45) is in a fixed position relative to said first jewel (42) or to said first arbor (43).
18. Mechanism (100) according to claim 15, characterized in that said second jewel (44) or said second arbor (45) is arranged to be guided in a variable position relative to said plate (40) and is subjected to the action of second elastic return means (47).
19. Mechanism (100) according to claim 15, characterized in that said plate (40) includes, on the one hand, a first jewel (42) or a first arbor (43) which is arranged to be guided in a variable position relative to said plate (40) and is subjected to the action of first elastic return means (46) for pivotally guiding said head (2) or said fork (6), and, on the other hand, a second jewel (44) or a second arbor (45) which is arranged to be guided in translation in a variable position relative to said plate (40) and is subjected to the action of second elastic return means (47) for pivotally guiding said fork (6) or said head (2) respectively.
20. Mechanism (100) according to any of claims 15 to 19, characterized in that the pivot axis (23) of said escape wheel (20), the pivot axis (32) of said balance (30), said first jewel (42) or respectively said first arbor (43), said second jewel (44) or respectively said second arbor (45) are aligned.
21. Timepiece movement (200) including at least one escapement mechanism (100) according to any of claims 9 to 20.
22. Timepiece (300) including at least one timepiece movement (200) according to claim 21 and/or at least one escapement mechanism (100) according to any of claims 9 to 20.

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