EP3128379B1 - Escapement with escape wheel with field rramps and a non-return device - Google Patents

Description

Field of the invention

The invention relates to a watch exhaust mechanism comprising at least one resonator and at least one escape wheel arranged to cooperate with a said resonator mechanism, either directly or indirectly through a stopper that includes said escape mechanism, said escape wheel comprising a succession of tracks carrying potential ramps of magnetic or electrostatic field, said ramps being arranged to cooperate with said resonator or respectively with said stop.

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

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

The invention relates to the field of exhaust mechanisms for mechanical watchmaking, and more particularly the field of controlled field escapements, known as magnetic exhausts, or electrostatic exhausts, or the like.

Background of the invention

The document EP2887157 in the name of SWATCH GROUP RESEARCH & DEVELOPMENT Ltd, an optimized watch escapement, with a stop cooperating on the one hand with a balance plate, and on the other hand with magnetic or electrostatic field barriers arranged on tracks of the escape wheel.

Such a device significantly improves the efficiency of the exhaust, due to reduced or non-existent contacts. However, its development is especially effective when the operation is not too abrupt. This is indeed to mitigate rebounds of the escape wheel, which can, if they are not controlled, lead to an unstable situation. In a traditional, fully mechanical Swiss lever escapement, the escape wheel provides the sprung balance with a certain amount of energy, coming from a barrel or other similar accumulator. The excess kinetic energy of the escape wheel is dissipated when one of its teeth falls on the rest plane of the pallet of the anchor, during the fall. This shock, very intense, effectively prevents the escape wheel from bouncing.

In an escapement with magnetic field or electrostatic barriers as described in the applications EP2887157 mentioned above, EP14186297 , EP14186296 and EP14186261 of the same applicant, all incorporated herein by reference, the interaction between a polar mass of the escape wheel (the "tooth") and a polar mass of the anchor (the "pallet") is conservative: the kinetic energy the wheel is no longer dissipated by the shock of the fall, it is restored almost completely to the wheel, in the opposite direction. Bounces are then observed. The figure 1 illustrates the principle: the escape wheel, pushed by the barrel, partially rises the magnetic potential barrier (or electrostatic as appropriate); when the pair of the barrier dominates the one provided by the barrel, the wheel stops and then starts again in the other direction. The wheel thus oscillates around a stable tilting position, which is always the same. The friction due to the pivots as well as aerodynamic losses end up damping the wheel after numerous oscillations.

Bounces are needed for constant strength operation as they help dissipate excess energy. Nevertheless, it is important to control their duration which must be less than the half-period for the system to work stably. On the other hand, it is interesting to completely prevent rebounds to store the excess energy in the magnetic potential, or electrostatic as appropriate, so as to recycle this energy, which then has the effect of increase the efficiency of the exhaust significantly.

The document EP2889704 A2 in the name of NIVAROX-FAR SA describes a clockwork escapement mechanism, comprising an escapement wheel subjected to a pivoting torque, of moment less than or equal to a nominal moment, around a first pivot axis, and a resonator integral with a regulating mobile mounted pivoting about a second axis of real or virtual pivoting. This escape wheel comprises a plurality of actuators regularly spaced on its periphery, and each arranged to cooperate directly with at least a first track of the mobile regulator. Each actuator comprises first magnetic or electrostatic barrier stop means and arranged to cooperate with the first track which is magnetized, respectively electrified, or ferromagnetic, or respectively conductive electrostatic, to exert on the first track a moment torque greater than the nominal moment. And each actuator further comprises second stop means arranged to constitute a stroke limiting stop, arranged to form an autonomous exhaust mechanism with at least a first abutment complementary surface that comprises the regulating mobile.

The document BE680716 in the name of Center Technique Horloger SA describes an electromechanical watch, comprising a device for transforming the oscillating movement of a resonator of frequency greater than 300 Hz into a continuous rotational movement without saccade, comprising a ratchet integral with the resonator driving a wheel. ratchet. The latter is secured to a coaxial pole wheel, of moment of inertia lower than that of the ratchet wheel, and magnetically driving another wheel, so that the influence on the ratchet wheel of the inertia of the driven wheel, practically negligible.

Summary of the invention

The purpose of a non-return device, such as a ratchet or the like in an exhaust device with a stop cooperating with a balance plate, and with magnetic or electrostatic field barriers, in particular in the form of a magnetic anchor, is to prevent the escape wheel from bouncing on the magnetic barriers, or electrostatic as appropriate.

The invention proposes to block the rebounds of such a magnetic or electrostatic exhaust device, by adding a non-return device, which makes it possible to temporarily store the energy of the escape wheel in the magnetic potential or electrostatic, in order to be able to return it to the balance or the like during the exhaust function, which has the effect of significantly increase the efficiency of this type of exhaust, especially when the torque provided by the barrel or the accumulator is high.

And, more particularly, the invention is concerned with increasing the energy efficiency of the escapement mechanism and the movement.

For this purpose, the invention relates to a clock escapement mechanism according to claim 1.

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

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

Brief description of the drawings

• la figure 1 représente, de façon schématisée, pour un mécanisme d'échappement de type magnétique, un diagramme illustrant la variation de l'énergie potentielle en ordonnée, en fonction de l'angle au centre en abscisse;
• la figure 2 représente, de façon schématisée, une simulation de l'évolution des rebonds de la roue d'échappement, avec l'angle de rotation de la roue en ordonnée, en fonction du temps en abscisse ;
• la figure 3 représente, de façon schématisée, selon une échelle de puissance en ordonnée en fonction du couple d'entraînement en abscisse, les canaux de pertes d'un échappement à ancre magnétique, la zone triangulaire illustrant la quantité absolue d'énergie perdue par les rebonds de la roue magnétique, et montrant qu'aux faibles valeurs de couple correspondant au désarmage du barillet le fonctionnement est tout juste assuré, tandis qu'aux fortes valeurs de couple fourni par le barillet ou l'accumulateur correspond un excès d'énergie disponibie qui tend à être dissipé par ie phénomène de rebond ;
• la figure 4 représente, de façon similaire à la figure 3, les pertes relatives, avec en ordonnée le ratio des pertes par rapport à la puissance totale, en fonction du couple d'entraînement en abscisse, la zone triangulaire supérieure illustrant la quantité relative d'énergie perdue par les rebonds de la roue magnétique ;
• la figure 5 représente, de façon similaire à la figure 1, la combinaison propre à l'invention entre le même échappement magnétique et un dispositif anti-retour, schématisé non limitativement par un cliquet ;
• la figure 6 représente, de façon schématisée, et en vue en plan, un échappement magnétique à arrêtoir comportant deux bras chacun portant une masse polaire agencée pour coopérer alternativement avec une piste de la roue d'échappement, laquelle est couplée à un dispositif anti-retour sous forme d'un cliquet ici non limitativement représenté sous forme d'un cliquet unique ;
• la figure 7 est une variante du mécanisme de la figure 6, où le cliquet ne coopère avec un secteur denté que dans certaines zones angulaires où la fonction d'anti-retour n'est pas nécessaire, de façon à minimiser les pertes lors de l'armage du dispositif anti-retour, notamment par frottement du cliquet dans ce cas de figure ;
• la figure 8 illustre une configuration de travail particulière du mécanisme de la figure 7, où le cliquet fonctionne en traction quand la roue d'échappement tend à pivoter à l'inverse de son sens normal de fonctionnement ;
• la figure 9 illustre, en vue en plan, une roue d'échappement simplifiée avec des rampes alternées dépourvues de barrière, et séparées en alternance par des zones de potentiel de champ nul ;
• la figure 10 illustre, en vue en plan, une roue d'échappement comportant deux pistes concentriques, avec des rampes alternées prolongées par des barrières de potentiel, et un arrêtoir de type ancre, à masse polaire unique, monté pivotant pour coopérer de façon alternée avec ces deux pistes ;
• la figure 11 est un schéma-blocs représentant une montre comportant un mouvement équipé d'un mécanisme d'échappement 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 schematically represents, for a magnetic type escapement mechanism, a diagram illustrating the variation of the potential energy on the ordinate, as a function of the center angle on the abscissa;
• the figure 2 represents, schematically, a simulation of the evolution of the rebounds of the escape wheel, with the rotation angle of the wheel in ordinate, as a function of time on the abscissa;
• the figure 3 schematically represents, according to a power scale in ordinate as a function of the driving torque on the abscissa, the loss channels of a magnetic anchor escapement, the triangular zone illustrating the absolute quantity of energy lost by the rebounds of the magnetic wheel, and showing that the low torque values corresponding to disarming the barrel operation is just assured, while the high torque values provided by the barrel or the accumulator is an excess of available energy that tends to be dissipated by the phenomenon of rebound;
• the figure 4 represents, similarly to the figure 3 relative losses, with ordinates the ratio of the losses with respect to the total power, as a function of the driving torque on the abscissa, the upper triangular zone illustrating the relative amount of energy lost by the rebounds of the magnetic wheel;
• the figure 5 represents, similarly to the figure 1 the combination according to the invention between the same magnetic escapement and a non-return device, schematized nonlimitingly by a pawl;
• the figure 6 schematically shows, in plan view, a magnetic arrestor escapement comprising two arms each carrying a pole mass arranged to cooperate alternately with a track of the escape wheel, which is coupled to a non-return device in the form of a ratchet here not limited to the form of a single ratchet;
• the figure 7 is a variant of the mechanism of the figure 6 , where the pawl cooperates with a toothed sector only in certain angular areas where the anti-return function is not necessary, so as to minimize losses during the arming of the non-return device, in particular by friction of the pawl in this case;
• the figure 8 illustrates a particular working configuration of the mechanism of the figure 7 , where the pawl operates in traction when the escape wheel tends to pivot contrary to its normal direction of operation;
• the figure 9 illustrates, in plan view, a simplified escape wheel with alternate ramps without barrier, and alternately separated by areas of zero field potential;
• the figure 10 illustrates, in plan view, an escape wheel comprising two concentric tracks, with alternating ramps extended by potential barriers, and an anchor type stopper, with a single polar mass, pivotally mounted to cooperate alternately with these two tracks ;
• the figure 11 is a block diagram showing a watch comprising a movement equipped with an exhaust mechanism according to the invention.

Detailed Description of the Preferred Embodiments

The invention proposes a simple and reliable solution for controlling the rebounds of a magnetic or electrostatic exhaust device, by adding a non-return device, which makes it possible to increase the efficiency of this type of exhaust, in particular when the torque provided by the barrel or the accumulator is high. This non-return mechanism makes it possible to accumulate the energy of the barrel or similar, to restore it in the resonator.

The invention relates to a horological escapement mechanism 200 comprising at least one resonator 100. The escape mechanism 200 comprises at least one escapement mobile. This mobile is described and illustrated here in the particular and non-limiting case of an escape wheel 1, but it can take other forms, such as a cylinder, or other. In this non-limiting variant, the escape mechanism 200 comprises at least one escape wheel 1, which is arranged to cooperate with such a resonator mechanism 100, either directly or indirectly through a stop 2 which comprises this exhaust mechanism 200.

The invention is illustrated, in a nonlimiting manner, with a stopper escapement, this stopper 2 being constituted in a particular example, again non-limiting, by a pivoting anchor comprising, as the case may be, a single polar mass 3 arranged to cooperate alternately with tracks of the wheel exhaust system comprising magnetic or electrostatic fields of variable intensity, or two polar masses 3 arranged to cooperate alternately with at least one track 4 of the escape wheel 1 comprising magnetic or electrostatic fields of variable intensity.

The invention also applies to other types of exhaust mechanisms, cylinder, natural, or other, in the case of direct cooperation without stop.

The escape wheel 1 comprising a succession of tracks 4, or alternatively, according to the variants described below 40, 41, 42. These tracks 4 carry ramps 6 of increasing magnetic or electrostatic field potential. These ramps 6 are arranged to cooperate with the resonator 100, or respectively with the stopper 2.

According to the invention, this escapement mechanism 200 comprises at least one anti-return device 5, which is arranged to oppose the return of the escape wheel 1, that is to say to prevent it from backward from its normal direction of rotation.

More particularly, the escape mechanism 200 comprises a stopper 2 cooperating, on the one hand with a plate that includes the resonator mechanism 100, in particular a balance plate in the case of a spring-balance resonator, and co-operating with on the other hand with ramps 6 of magnetic or electrostatic field potential, by at least one polar mass 3, or else, according to the variants described below 30, 31, 32, that comprises this retainer 2. This polar mass 3 is arranged to evolve in the field corresponding to these ramps 6 of magnetic or electrostatic field potential.

The figure 1 resumes the lessons of the request EP28871573 , relating to a magnetic escapement device 200 with a single polar pole retainer 2 pivoting so as to cooperate alternately with an inner track and an outer track, as shown in FIG. figure 10 . This diagram illustrates the variation of the potential energy, along the ordinate, along the magnetized tracks, as a function of the angle at the center on the abscissa, for each of the two tracks of the figure 1 : internal track in solid line, and outer track in broken lines, each comprising a succession of magnetized zones with different intensities, and exerting different repulsion efforts in interaction with the polar mass of the anchor when the latter is in their vicinity immediate areas immediately adjacent two neighboring concentric tracks being also of different magnetization level.

This figure 1 shows the accumulation of potential energy taken from the escape wheel 1 on the sections P1-P2 and P3-P4 each corresponding to half a period, and its restitution by the anchor 2 to the pendulum during the change of track of polar mass P2-P3 and P4-P5. This figure 1 shows a particular position PP, at a significant slope change between a ramp 6 and a potential barrier 7 which extends it, around which position PP bounces are damped due to the play of the potential slopes of the fields. The value ER denotes the energy of the ramp 6 at this point, that is to say the difference between the energy level of this particular point PP, and the minimum potential level of the tracks 4 of the escape wheel 1 .

The invention is described and illustrated here in the magnetic alternative, with anti-return device on the escape wheel; the person skilled in the art will know how to carry out the electrostatic and mixed alternatives with reference to the patent applications mentioned above, from the same applicant.

The energy dissipation during rebounds is conventionally done by friction, at least partially viscous, especially at the pivots, and aerodynamic losses, as visible on the figure 2 .

An important advantage of the magnetic field or electrostatic exhaust mechanisms is that the tipping point is fixed, perfectly reproducible, and the transmitted energy is constant. In such a configuration, the anchor always switches to the same position, at the foot of the magnetic barrier when it exists (which is not always the case, one can also have the combination of a simple ramp and a mechanical stop to play the role of the potential barrier). The stopper or anchor therefore always transmits the same amount of energy to the balance, which makes it a system with constant force, the surplus being dissipated by rebounds.

• puissance utile reçue par le résonateur PU;
• pertes ancre (chocs) PAC ;
• pertes dans les rebonds de la roue (secteur triangulaire) PRDR ; ces pertes peuvent être importantes quand le barillet est complètement armé ; le système est dimensionné pour fonctionner tout juste à couple faible, en fin de désarmage du barillet ;
• pertes rotation roue et rouage PRER,
• la droite oblique supérieure représentant le cumul, c'est-à-dire la puissance totale fournie par le barillet PTFB.

The barrel does not always provide the same torque, this surplus energy dissipated by rebounds is not constant, as can be seen on the figure 3 , which shows the different loss channels of the magnetic anchor escapement, from bottom to top:

• useful power received by the PU resonator;
• anchor losses (shocks) PAC;
• losses in the rebounds of the wheel (triangular sector) PRDR; these losses can be significant when the barrel is fully armed; the system is sized to operate just at low torque, at the end of disarming the barrel;
• wheel and gear rotation losses PRER,
• the upper oblique line representing the cumulative, that is to say the total power provided by the PTFB cylinder.

The triangular zone represents the absolute amount of energy lost by the rebounds of the magnetic wheel.

The figure 4 shows, in the same order, the same quantities which are represented in relative values with respect to the total power supplied to the escape wheel. This figure 4 shows that, when the torque of the barrel is high, the proportion of energy lost (not transmitted to the sprung balance) in rebounds becomes very important, almost 50%. Full removal of bounces is not possible.

The invention is compelled to minimize as much as possible these rebounds by adding a non-return device, such as a ratchet or the like, acting on the escape wheel.

This is both to limit rebounds to a minimum, and especially to increase the efficiency of the exhaust mechanism, and therefore the power reserve of the watch movement.

The principle is illustrated on the figure 5 . The tipping point now depends on the torque, the transmitted energy is then variable
The exhaust can therefore transfer more energy to the sprung balance. The yield is improved. The system loses its constant force characteristic and becomes a variable force exhaust with the torque, like a traditional Swiss anchor escapement.

Various configurations of distribution of the fields on the track or tracks 4 of the escape wheel 1 are usable.

In a first embodiment illustrated by the figure 10 , the stop 2 comprises a polar mass 3 which is a single polar mass 30 arranged to cooperate successively and alternately with two tracks 4 which are a first track 41 and a second track 42.

In a second embodiment, the stopper 2 comprises two polar masses 3, which are a first polar mass 31 and a second polar mass 32, arranged to cooperate successively and alternately with a track 4 which is a single track 40.

And the escape wheel 1 comprises, arranged periodically in a pitch P, a plurality of useful zones ZU, each located between, on the one hand, a zone of minimum potential of such a track 4, 40, 41, 42, given, and on the other hand a zone of maximum potential of such a track 4, 40, 41, 42, which zone of maximum potential immediately follows the zone of potential minimum considered of this given track.

And each crossing of such a zone of maximum potential of a track 4, 40, 41, 42 by a polar mass 3, 30, 31, 32, corresponds to a tilting of the stop 2
In the particular configuration comprising both ramps 6 and potential barriers 7, the magnetic or electrostatic field potential ramps 6 disposed on these tracks 4, 40, 41, 42, each comprise a barrier 7 of potential at their end. of maximum field potential, tending to oppose its crossing by a polar mass 3 of the stop 2.

More particularly, on such a track 4, 40, 41, 42, each ramp 6 is extended by a barrier 7 of magnetic or electrostatic field, this barrier 7 comprising immediately following the ramp 6, at the particular point PP, a first zone 71 of rapid growth potential whose gradient is greater than the maximum gradient of the ramp 6 concerned. This first zone 71 is followed by a second zone 72 of potential maximum where the concavity of the potential curve is inverted with respect to the first zone 71. The second zone 72 is immediately followed by a third zone 73 of potential decay. where the concavity of the potential curve is reversed with respect to the second zone 72, and this third zone 73 ends with a fourth zone 74 of minimum potential.

In the particular configuration of the figure 10 each useful zone ZU is located between, on the one hand, a fourth zone 74 of potential minimum of a said track 4, 40, 41, 42, given, and on the other hand a second zone 72 of maximum potential of such a track 4, 40, 41, 42, immediately following this fourth zone 74 of potential minimum of this given track. And each crossing of a such second zone 72 of maximum potential of a track 4, 40, 41, 42, by such a polar mass 3, 30, 31, 32, corresponds to a tilting of the stopper 2.

In a chained configuration like on the figure 10 on a track 4, 40, 41, 42, each said first zone 71 immediately follows the fourth zone 74 preceding.

More particularly, on the exhaust wheel 1 in its entirety, each first zone 71 immediately follows the fourth zone 74 previous.

In a fragmented configuration like on the figure 9 on a track 4, 40, 41, 42, each first zone 71 is separated from the fourth zone 74 preceding by a fifth zone 75 of constant potential or zero.

More particularly, on the escape wheel 1 in its entirety, each first zone 71 is separated from the fourth zone 74 preceding by a fifth zone 75 of constant or zero potential.

In particular variants, as in particular on the figure 9 , the magnetic or electrostatic field potential ramps 6 disposed on the tracks 4 have no potential barrier at their maximum potential end, and the tracks 4 each comprise alternating zones of zero potential and such ramps 6. And, advantageously, in such cases, the magnetic or electrostatic field potential ramps 6 arranged on the tracks 4, 40, 41, 42, are each associated, at its zone of maximum potential, with a mechanical stop preventing its crossing. by a polar mass 3 of the stop 2
In the variants with retainer 2, the non-return device 5 may comprise, without limitation: a compression pawl 51, a traction pawl 52, an internal compression pawl 53, or an inner pull pawl, or combinations of these different pawls, or any other mechanism tending to oppose the retreat of the escape wheel 1.

The figure 6 shows a compression pawl 51 comprising a first elastic connection with a first fixed part of the escape mechanism 200 outside the stop 2 and the escape wheel 1, this compression pawl 51 cooperates with at least one fixed toothing 10 in pivoting of the escape wheel 1. A single pawl 51 is shown not to overload the figure, but it is clear, as for the other variants, that the mechanism may comprise a plurality of such ratchets, including types different. Of the same way, the mechanism may have several teeth, for example above and below the median plane of the wheel 1, and optionally alternately.

Preferably, this at least one toothing 10 is a toothing with wolf teeth, allowing the advance of the escape wheel 1 by sliding on the compression pawl 51 and opposing the retreat of the escape wheel 1 subjecting this at least one compression pawl 51 to a buckling force when the escape wheel 1 tends to recoil.

On the figure 7 , the non-return device 5 comprises at least one traction pawl 52 comprising a second elastic connection with a second fixed part of the escape mechanism 200 outside the stop 2 and the escape wheel 1. This at least one pulling pawl 52 cooperates with this at least one toothing 10, and is arranged to operate in traction and exert on the escape wheel 1 a torque tending to advance, when the escape wheel 1 tends to move back. This pull pawl 52 may be either constituted by the preceding pawl 51 or be constituted by a separate pawl. The toothing 10 is preferably arranged in a similar manner to the previous case.

In another variant, the ratchet is loaded onto the escape wheel and the teeth are arranged on a fixed wheel. The non-return device 5 then comprises at least one inner compression pawl 53 comprising a third elastic connection with the escape wheel 1 and cooperating with at least one toothing 10 that comprises a toothed ring internally fixed on a fixed part of the mechanism of Exhaust 200 outside the stop 2 and the escape wheel 1.

Regarding the toothing 10, various arrangements are imaginable.

The variant of the figure 7 shows that this at least one set of teeth 10 periodically comprises, in alternation with zones provided with teeth 11, zones devoid of teeth 12 to minimize losses when the non-return function is not necessary, when said polar mass 3 the stop 2 cooperates with a zone 8 of zero potential (or zero gradient: constant potential) of a track 4, 40, 41, 42, or a low potential area of a ramp 6.

To ensure minimal operation, the at least one toothing 10 must have at least one tooth 13 on each useful zone ZU. This reduces the cost of cutting or cutting teeth. For example, the figure 10 shows three teeth 13 only for each useful zone ZU.

In a more conventional version, this at least one toothing 10 comprises, on the zones provided with teeth that it comprises, at least twenty times more teeth than the escape wheel 1 does not have P steps (also called tooth equivalents ), each pitch P corresponding to the race between two successive tilts of the stop 2. Of course, friction losses exist, they are nonetheless constant, and do not affect the chronometric performance.

The figure 6 illustrates a variant of non-return device constituted by a pawl on the magnetic escape wheel. In an advantageous variant, the pawl has a high resolution, which ensures that the anti-return wheel is performed correctly. Preferably, the anti-return device comprises at least twenty times more teeth than there are teeth equivalents to the escape wheel. On the non-limiting example of the figure 6 there are six teeth equivalents at the wheel and one hundred and eighty at the level of the toothing which cooperates with the pawl.

The arming of the ratchet teeth consumes a little energy and alters the performance of the exhaust. It is possible to minimize this problem by placing teeth only in the functional regions, as shown on the diagram. figure 7 . The auto-start of the exhaust is then also improved, provided that the ratchet blade is not too pre-armed.

The figure 7 thus shows areas spared, so as to minimize losses, in areas of work where the anti-return function is not necessary, that is to say in areas of lower (or zero) potential of field.

The figures 6 and 7 show a first variant where the pawl comprises an elastic blade, which works in compression when the wheel tries to move back.

A second variant, in figure 8 relates to a pawl that works in traction, when the wheel tends to move back.

Many other non-return devices can be envisaged, such as for example the system used in automatic reversers in automatic movements with oscillating weight winding, as described on: http://www.horlogerie-suisse.com/technique/ the-complications / the reversing-automatic
It is still possible to use, in combination, a hard blade on a soft wheel, rubber or the like.

In another variant, this non-return device 5 comprises at least one freewheel device, or a low rolling hysteresis mechanism of "OneWay" type from the company "MPS": http: //www.mps-watch. com / en / bearing-technology / produits.html # C581.

The presence of a non-return device offers another advantage that combines with the advantages of operation: the magnetic potential may be lower, which simplifies the manufacture of magnets, and lowers costs.

Another combination is to use the original potential, but with a cylinder dimensioned to the fair, so much less bulky, which is still sought after in watchmaking, especially in the case of ladies' watches or watches with complications.

Of course, one can choose, all other things being equal, to simply increase the power reserve of the movement.

The figure 9 illustrates another simplified embodiment, with magnetic or electrostatic tracks without a field barrier, only with alternating ramps, with zones having a null potential, interposed between the ramps, as illustrated on FIG. figure 8 . The start is further simplified, and the usable torque range is even greater.

It will be understood that the use of a non-return device does not make it possible to dispense with the mechanical anti-shock abutments mentioned in the document EP2887157 .

The production of exhaust mechanisms according to the invention is possible both with traditional technologies, including milling or stamping, or laser machining to obtain a higher resolution, appreciable for the machining of the toothing 10.

One can, further, minimize the power required to operate the anti-return device, using modern manufacturing technologies, such as deep silicon etching or LIGA. In particular, it seeks to minimize the inertia, the spring constant, or the coefficient of friction.

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

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

In sum, the anti-return device according to the invention makes it possible, at the cost of a low-cost and limited space arrangement, to obtain a large increase in the efficiency of the exhaust mechanism, and consequently of the power reserve of the movement.

Claims (20)

1. Timepiece escapement mechanism (200) comprising at least one resonator (100) and at least one escape wheel (1) arranged such that it engages with one said resonator mechanism (100), or directly or indirectly through a stopping device (2) comprised in said escapement mechanism (200), said escape wheel (1) comprising a succession of tracks (4; 40; 41; 42) bearing ramps (6) of increasing magnetic or electrostatic field potential, said ramps (6) being arranged such that they engage with said resonator (100) or respectively with said stopping device (2), characterised in that said escapement mechanism (200) comprises at least one non-return device (5) arranged to oppose the return of said escape wheel (1), characterised in that said escapement mechanism (200) comprises a stopping device (2) engaging, on the one hand with a plate comprised in said resonator mechanism (100), and on the other hand with ramps (6) of magnetic or electrostatic field potential, by at least one pole piece (3; 30; 31; 32) comprised in said stopping device (2) and that is arranged such that it moves in the field corresponding to said ramps (6) of magnetic or electrostatic field potential, characterised in that said non-return device (5) comprises at least one pressing pawl (51) comprising a first resilient connection with a first fixed part of said escapement mechanism (200) external to said stopping device (2) and to said escape wheel (1), said at least one pressing pawl (51) engaging with at least one toothing (10) pivotably connected to said escape wheel (1), and characterised in that said at least one toothing (10) is a wolf tooth toothing allowing said escape wheel (1) to advance by sliding on said pressing pawl (51) and opposing the recoil of said escape wheel (1) by subjecting said at least one pressing pawl (51) to a buckling force when said escape wheel (1) has a tendency to recoil.
2. Escapement mechanism (200) according to claim 1, characterised in that said stopping device (2) comprises, either one said pole piece (3) which is a single pole piece (30) arranged such that it successively and alternately engages with two said tracks (4) which are a first track (41) and a second track (42), or two said pole pieces (3) which are a first pole piece (31) and a second pole piece (32) arranged such that they successively and alternately engage with one said track (4) which is a single track (40), and in that said escape wheel (1) comprises, arranged periodically according to a pitch (P), a plurality of useful areas (ZU), each of which is situated between, on the one hand an area of minimum potential of one said given track (4; 40; 41; 42), and on the other hand an area of maximum potential of one said track (4; 40; 41; 42) immediately following said area of minimum potential of said given track (4; 40; 41; 42), and in that each crossing of one said area of maximum potential of one said track (4; 40; 41; 42) by one said pole piece (3; 30; 31; 32) corresponds to a tipping of said stopping device (2).
3. Escapement mechanism (200) according to either claim 1 or claim 2, characterised in that said ramps (6) of magnetic or electrostatic field potential arranged on said tracks (4; 40; 41; 42) each comprise a potential barrier (7) at the maximum field potential end thereof, tending to oppose the crossing thereof by said pole piece (3) of said stopping device (2).
4. Escapement mechanism (200) according to one of claims 1 to 3, characterised in that, on one said track (4; 40; 41; 42), each said ramp (6) is extended by a magnetic or electrostatic field barrier (7), said barrier (7) comprising, immediately after said ramp (6) a first area (71) of rapid growth of potential, the gradient whereof is higher than the maximum gradient of said ramp (6), said first area (71) being followed by a second area (72) of maximum potential, where the concavity of the potential curve is inverted in relation to said first area (71), said second area (72) being immediately followed by a third area (73) of decline in potential where the concavity of the potential curve is inverted in relation to said second area (72), and said third area (73) ending at a fourth area (74) of minimum potential.
5. Escapement mechanism (200) according to claims 2 and 4, characterised in that each said useful area (ZU) is situated between, on the one hand, one said fourth area (74) of minimum potential of one said given track (4; 40; 41; 42), and on the other hand one said second area (72) of maximum potential of one said track (4; 40; 41; 42) immediately following said fourth area (74) of minimum potential of one said given track (4; 40; 41; 42), and in that each crossing of one said second area (72) of maximum potential of one said track (4; 40; 41; 42) by one said pole piece (3; 30; 31; 32) corresponds to a tipping of said stopping device (2).
6. Escapement mechanism (200) according to either claim 4 or claim 5 characterised in that, on one said track (4; 40; 41; 42), each said first area (71) immediately follows said preceding fourth area (74).
7. Escapement mechanism (200) according to either claim 4 or claim 5 characterised in that, on said escape wheel (1), each said first area (71) immediately follows said preceding fourth area (74).
8. Escapement mechanism (200) according to either claim 4 or claim 5 characterised in that, on one said track (4; 40; 41; 42), each said first area (71) is separated from said preceding fourth area (74) by a fifth area (75) of constant or zero potential.
9. Escapement mechanism (200) according to either claim 4 or claim 5 characterised in that, on said escape wheel (1), each said first area (71) is separated from said preceding fourth area (74) by a fifth area (75) of constant or zero potential.
10. Escapement mechanism (200) according to either claim 1 or claim 2, characterised in that said ramps (6) of magnetic or electrostatic field potential arranged on said tracks (4) are devoid of any potential barrier at the maximum field potential end thereof, and in that said tracks (4) each comprise an alternation of areas of constant or zero potential (8) and of said ramps (6).
11. Escapement mechanism (200) according to either claim 1 or claim 2, characterised in that said ramps (6) of magnetic or electrostatic field potential arranged on said tracks (4; 40; 41; 42) are each associated, at the area of maximum potential thereof, with a mechanical stop preventing the crossing thereof by a said pole piece (3) of said stopping device (2).
12. Escapement mechanism (200) according to one of claims 1 to 11, characterised in that said non-return device (5) is arranged such that it minimises the rebounds of said escape wheel (1) on at least one part of the angular stroke of said escape wheel (1).
13. Escapement mechanism (200) according to one of claims 1 to 12, characterised in that said non-return device (5) comprises at least one traction pawl (52) comprising a second resilient connection with a second fixed part of said escapement mechanism (200) external to said stopping device (2) and to said escape wheel (1), said at least one traction pawl (52) engaging with said at least one toothing (10) and arranged such that it operates by traction and exerts a torque on said escape wheel (1) that tends to cause it to advance, when said escape wheel (1) has a tendency to recoil, said traction pawl (52) being formed either by said pressing pawl (51) or by a separate pawl.
14. Escapement mechanism (200) according to one of claims 1 to 12, characterised in that said non-return device (5) comprises at least one inner pressing pawl (53) comprising a third resilient connection with said escape wheel (1) and engaging with a toothing (10) comprised in a toothed ring internally attached to a fixed part of said escapement mechanism (200) external to said stopping device (2) and to said escape wheel (1).
15. Escapement mechanism (200) according to one of claims 1 to 14, characterised in that said at least one toothing (10) periodically comprises, alternating with areas fitted with teeth (11), areas devoid of teeth (12) in order to minimise losses when the non-return function is not necessary, when said pole piece (3) of said stopping device (2) engages with an area of zero potential of one said track (4; 40; 41; 42) or an area of low potential of one said ramp (6).
16. Escapement mechanism (200) according to either claim 2 or claim 4, and according to one of claims 1 to 15, characterised in that said at least one toothing (10) comprises at least one tooth (13) in each said useful area (ZU).
17. Escapement mechanism (200) according to either claim 2 or claim 4, and according to one of claims 1 to 15, characterised in that said at least one toothing (10) comprises, in the areas fitted with teeth comprised therein, at least twenty times more teeth than said escape wheel (1) has said pitches (P), each said pitch (P) corresponding to the stroke between two successive tipping movements of said stopping device (2).
18. Escapement mechanism (200) according to one of claims 1 to 17, characterised in that said non-return device (5) comprises at least one free wheel device.
19. Clock movement (300) comprising at least one escapement mechanism (200) according to one of claims 1 to 18.
20. Watch (400) comprising at least one escapement mechanism (200) according to one of claims 1 to 18.

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