CH711404A2 - A clock exhaust mechanism comprising an exhaust wheel with field ramps and non-return valve. - Google Patents

Abstract

The invention relates to a clockwork exhaust mechanism (200) comprising at least one resonator (100) and at least one escape wheel (1) arranged to cooperate with such a resonator mechanism (100), or directly, or indirectly through a stop (2) that includes the exhaust mechanism (200), the escape wheel (1) having a succession of tracks (4) carrying ramps (6) of magnetic field potential or electrostatic, these ramps (6) being arranged to cooperate with the resonator (100) or respectively with the retainer (2). This escape mechanism (200) comprises a non-return device (5) arranged to oppose the recoil of the escape wheel (1).

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, or directly, or indirectly through a stop said exhaust mechanism comprises said exhaust 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 exhaust mechanism.

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

Background of the invention

[0005] The document EP 2 887 157 in the name of SWATCH GROUP RESEARCH & DEVELOPMENT Ltd. describes an optimized watch escapement, with a stop cooperating on the one hand with a balance plate, and on the other hand with field barriers. magnetic or electrostatic disposed on tracks of the escape wheel.

Such a device significantly improves the efficiency of the exhaust, because of reduced or non-existent contacts. However, its development is especially effective when the operation is not too abrupt. This is indeed to mitigate the rebounds of the escape wheel, which can, if they are not mastered, 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 or electrostatic field barriers as described in applications EP 2,887,157 cited above, EP 14,186,297, EP 14,186,296 and EP 14,186,261 of the same applicant, all incorporated here 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 of the wheel is more dissipated by the shock of the fall, it is restored almost entirely to the wheel, in the opposite direction. Bounces are then observed. Fig. 1 illustrates the principle: the escape wheel, pushed by the barrel, partially rises the magnetic potential barrier (or electrostatic as appropriate); when the torque of the barrier dominates that provided by the barrel, the wheel stops and then starts again in the other direction, so that the wheel oscillates around a stable tilting position, which is always the same. Pivots and aerodynamic losses end up damping the wheel after many oscillations.

The rebounds are necessary for operation with constant force since they allow to dissipate the 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.

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 under 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 allows to temporarily store the energy of the escape wheel in the magnetic or electrostatic potential, in order to be able to restore it to the balance or the like during the exhaust function, which has the effect of significantly increasing the efficiency of this type of exhaust, especially when the torque provided by the cylinder or the accumulator is high.

And, more particularly, the invention is to increase the energy efficiency of the exhaust mechanism and movement.

For this purpose, the invention relates to a watch exhaust mechanism according to claim 1.

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

The invention further relates to a watch comprising at least one such exhaust mechanism.

Brief description of the drawings

Other features and advantages of the invention will appear on reading the detailed description which follows, with reference to the accompanying drawings, in which: <tb> fig. 1 <SEP> schematically represents, for a magnetic type escape mechanism, a diagram illustrating the variation of the potential energy on the ordinate, as a function of the center angle on the abscissa; <tb> fig. 2 <SEP> 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; <tb> fig. 3 <SEP> represents, schematically, 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 lost energy by the rebounds of the magnetic wheel, and showing that the low values of torque corresponding to the disarming of the barrel operation is just assured, while the high values of torque provided by the barrel or the accumulator is an excess of available energy that tends to be dissipated by the rebound phenomenon; <tb> fig. 4 <SEP> represents, similarly to FIG. 3, the relative losses, with the ordinate the ratio of 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 bouncing of the magnetic wheel; <tb> fig. <SEP> represents, similarly to FIG. 1, the combination of the invention between the same magnetic escapement and a non-return device, schematically not limited to a pawl; <tb> fig. 6 <SEP> represents, schematically, and in plan view, a magnetic escapement with stopper comprising two arms each carrying a pole mass arranged to cooperate alternately with a track of the escape wheel, which is coupled to a device -return in the form of a pawl here not limited to the form of a single pawl; <tb> fig. 7 <SEP> is a variant of the mechanism of FIG. 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 the losses during the arming of the non-return device, in particular by friction ratchet in this case; <tb> fig. 8 <SEP> illustrates a particular working configuration of the mechanism of FIG. 7, where the pawl operates in traction when the escape wheel tends to pivot in the opposite of its normal direction of operation; <tb> fig. 9 <SEP> illustrates, in plan view, a simplified escape wheel with alternate ramps without barrier, and alternately separated by areas of zero field potential; <tb> fig. 10 <SEP> 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 in a manner alternated with these two tracks; <tb> fig. 11 <SEP> is a block diagram showing a watch comprising a movement equipped with an escape mechanism according to the invention.

Detailed Description of the Preferred Embodiments

The invention proposes a simple and reliable solution to control the rebounds of a magnetic or electrostatic exhaust device, by adding a non-return device, which increases the efficiency of this type of exhaust , especially 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 200 watchmaking escapement mechanism comprising at least one resonator 100. The exhaust 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, without limitation, with a stopper escapement, this stopper 2 being constituted in a particular example, again non-limiting, by a pivoting anchor comprising, as appropriate a polar mass 3 arranged single to cooperate alternately with tracks of the escape wheel 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 fields or electrostatic 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 escape 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 for the prevent backing from its normal direction of rotation.

More particularly, the escapement mechanism 200 comprises a stopper 2 cooperating, on the one hand with a plate that includes the resonator mechanism 100, including a rocker plate in the case of a spring-balance resonator, and cooperating on the other hand with ramps 6 of magnetic or electrostatic field potential, by at least one polar mass 3, or alternatively, according to the variants described below 30, 31, 32, that includes 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.

FIG. 1 reproduces the teachings of the application EP 28 871 573, relating to a magnetic escapement device 200 with a stopper 2 with a single pole mass pivoting so as to cooperate alternately with an internal track and an external track, as represented on FIG. fig. 10. This diagram illustrates the variation of the potential energy, along the y-axis, along the magnetized tracks, as a function of the angle at the center on the abscissa, for each of the two tracks of FIG. 1: internal track in full line, and external 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 immediate neighborhood, the immediately adjacent zones of the two concentric neighboring tracks being also of different magnetization level.

This fig. 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 polar mass P2-P3 and P4-P5. This fig. 1 shows a particular position PP, at a significant change in slope 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 by aerodynamic losses, as shown in FIG. 2.

An important advantage of magnetic or electrostatic field exhaust mechanisms is that the tilting 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.

The barrel does not always provide the same torque, this surplus energy dissipated by rebounds is not constant, as can be seen in FIG. 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.

FIG. 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 FIG. 4 shows that, when the torque of the barrel is high, the proportion of energy lost (not transmitted to the sprung balance) in the rebounds becomes very important, almost 50%. Full removal of bounces is not possible.

The invention is compelled to minimize these rebounds as much as possible 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 in FIG. 5. The tipping point now depends on the torque, the energy transmitted 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 field distribution configurations on the track or tracks 4 of the escape wheel 1 are usable.

In a first embodiment illustrated in FIG. 10, the stop 2 comprises a polar mass 3 which is a single polar mass 30 arranged to cooperate successively and alternatively 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 potential maximum 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 ramps 6 of magnetic or electrostatic field potential 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 point particular 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 FIG. 10, each useful zone ZU is situated between, on the one hand, a fourth zone 74 of minimum potential 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 such a second region 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 as in FIG. 10, on a track 4, 40, 41, 42, each said first zone 71 immediately follows the fourth zone 74 previous.

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

In a fragmented configuration as in FIG. 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 potential or zero.

In particular variants, such as in particular in FIG. 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 ramps 6 of magnetic or electrostatic field potential arranged on the tracks 4, 40, 41, 42, are each associated, at its maximum potential area, 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 inner compression pawl 53, or an inner traction pawl, or combinations of these different pawls, or any other mechanism tending to oppose the retreat of the escape wheel 1.

FIG. 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 toothing 10 integral with 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 pawls, including different types. In the same way, the mechanism may comprise several teeth, for example above and below the median plane of the wheel 1, and possibly alternately.

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

In FIG. 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 stopper 2 and the escape wheel 1. This at least a 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 it, 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, we embark the pawl on the escape wheel and arranging the toothing 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 FIG. 7 shows that this at least one toothing 10 periodically comprises, in alternation with areas provided with teeth 11, areas devoid of teeth 12 to minimize losses when the anti-return function is not necessary, when said polar mass 3 of the stop 2 cooperates with a zone 8 of potential zero (or zero gradient: constant potential) of a track 4, 40, 41, 42, or a low potential area of a ramp 6.

To ensure the minimum operation, it is necessary that the at least one toothing 10 comprises at least one tooth 13 on each useful zone ZU. This reduces the cost of cutting or cutting teeth. For example, FIG. 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 include P (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 nevertheless constant, and do not affect the chronometric performance.

FIG. 6 illustrates an alternative non-return device consisting of 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. In the nonlimiting example of FIG. 6, there are six teeth equivalents at the wheel and one hundred and eighty at the level of the toothing that 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 in FIG. 7. The auto-start of the exhaust is then also improved, provided that the ratchet blade is not too pre-armed.

FIG. 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 the areas of lower (or zero) field potential.

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

A second variant, in fig. 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 the system used in automatic inverters in the winding movements, as described on: http://www.horlogerie-suisse.com / technical / the-complications / the reversing-automatic.

It is also 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 of the company "MPS": http: //www.mps-watch.eom/fr/bearing-technologies/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 at most 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.

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

It is understood that the use of a non-return device does not overcome the mechanical abutments shock mentioned in EP 2887157.

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

We can, still, 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 further relates to a watch comprising at least one such exhaust mechanism.

In sum, the nonreturn device according to the invention allows, at the cost of a low cost and limited space development, to obtain a large increase in the efficiency of the exhaust mechanism, and, consequently , the power reserve of the movement.

Claims (23)

1. Watch exhaust mechanism (200) comprising at least one resonator (100) and at least one escape wheel (1) arranged to cooperate with a said resonator mechanism (100), or directly, or indirectly through a stop (2) that includes said exhaust mechanism (200), said escape wheel (1) having a succession of tracks (4; 40; 41; 42) carrying ramps (6) potential increasing magnetic or electrostatic field, said ramps (6) being arranged to cooperate with said resonator (100) or respectively with said retainer (2), characterized in that said exhaust mechanism (200) comprises at least one anti-rotation device return (5) arranged to oppose the return of said escape wheel (1). 2. Exhaust mechanism (200) of timepiece according to claim 1, characterized in that said exhaust mechanism (200) comprises a stop (2) cooperating on the one hand with a plate that includes said resonator mechanism ( 100), and secondly with ramps (6) of magnetic or electrostatic field potential, by at least one polar mass (3; 30; 31; 32) that comprises said stop (2) and which is arranged to evolve in the field corresponding to said ramps (6) of magnetic or electrostatic field potential. 3. Exhaust mechanism (200) according to claim 2, characterized in that said retainer (2) comprises, or a said polar mass (3) which is a single polar mass (30) arranged to cooperate successively and alternately with two said tracks (4) which are a first track (41) and a second track (42), or two so-called polar masses (3) which are a first polar mass (31) and a second polar mass (32) arranged for cooperating successively and alternatively with a said track (4) which is a single track (40), and in that the said escape wheel (1) comprises, arranged periodically in a step (P), a plurality of useful zones (ZU) each located between, on the one hand, an area of potential minimum of a given track (4; 40; 41; 42), and on the other hand a zone of maximum potential of a said track ( 4; 40; 41; 42) immediately following said minimum potential area of said track (4; 40; 41; 42); given, and in that each crossing of a said maximum potential area of a said track (4; 40; 41; 42) by a said polar mass (3; 30; 31; 32) corresponds to a tilting of said retainer (2). 4. Exhaust mechanism (200) according to claim 2 or 3, characterized in that said ramps (6) of magnetic or electrostatic field potential disposed on said tracks (4; 40; 41; 42) each comprise a barrier ( 7) of potential at their maximum potential end of field, tending to oppose its crossing by said polar mass (3) of said stop (2). 5. Exhaust mechanism (200) according to one of claims 1 to 4, characterized in that, on a said track (4; 40; 41; 42) each said ramp (6) is extended by a barrier (7). ) of a magnetic or electrostatic field, said barrier (7) comprising immediately following said ramp (6) a first zone (71) of rapid growth potential whose gradient is greater than the maximum gradient of said ramp (6), said first zone (71) being followed by a second zone (72) of potential maximum where the concavity of the potential curve is inverted with respect to said first zone (71), said second zone (72) being immediately followed by a third zone (73) of potential decay where the concavity of the potential curve is inverted with respect to said second zone (72), and said third zone (73) ends with a fourth zone (74) of minimum potential . 6. Exhaust mechanism (200) according to claims 3 and 5, characterized in that each said useful zone (ZU) is located between, on the one hand a said fourth zone (74) of minimum potential of a said track (4; 40; 41; 42) given, and secondly a second zone (72) of maximum potential of a said track (4; 40; 41; 42) immediately following said fourth zone (74) a minimum potential of said said track (4; 40; 41; 42) given, and in that each crossing of a said second zone (72) of maximum potential of a said track (4; 40; 41; 42) by a said polar mass (3; 30; 31; 32) corresponds to a tilting of said retainer (2). 7. Exhaust mechanism (200) according to claim 5 or 6, characterized in that, on a said track (4; 40; 41; 42), each said first zone (71) immediately follows said fourth zone ( 74) previous. 8. Exhaust mechanism (200) according to claim 5 or 6, characterized in that, on said escape wheel (1), each said first zone (71) immediately follows said fourth zone (74) above. 9. Exhaust mechanism (200) according to claim 5 or 6, characterized in that, on a said track (4; 40; 41; 42), each said first zone (71) is separated from said fourth zone (74). ) preceding by a fifth zone (75) of constant potential or zero. 10. Exhaust mechanism (200) according to claim 5 or 6, characterized in that, on said escape wheel (1), each said first zone (71) is separated from said preceding fourth zone (74) by a fifth zone (75) of constant potential or zero. 11. Exhaust mechanism (200) according to one of claims 1 to 3, characterized in that said ramps (6) of magnetic or electrostatic field potential disposed on said tracks (4) are devoid of a potential barrier to their end of maximum field potential, and in that said tracks (4) each comprise an alternation of zones of constant or zero potential (8) and said ramps (6). 12. Exhaust mechanism (200) according to claim 2 or 3, characterized in that said ramps (6) of magnetic or electrostatic field potential arranged on said tracks (4; 40; 41; 42) are each associated with the level of its zone of maximum potential, a mechanical stop prohibiting its crossing by a so-called polar mass (3) of said stop (2). 13. Exhaust mechanism (200) according to one of claims 1 to 12, characterized in that said non-return device (5) is arranged to minimize the rebounds of said escape wheel (1) on at least one part of the angular travel of said escape wheel (1). 14. Exhaust mechanism (200) according to claim 2 or 3 or one of claims 4 to 13 when dependent on claim 2, characterized in that said non-return device (5) comprises at least one pawl of compression device (51) comprising a first elastic connection with a first fixed part of said exhaust mechanism (200) external to said stop (2) and said escape wheel (1), said at least one compression pawl (51) cooperating with at least one toothing (10) integral in pivoting of said escape wheel (1). 15. Exhaust mechanism (200) according to claim 14, characterized in that said at least one toothing (10) is a teeth with wolf teeth allowing the advance of said escape wheel (1) by sliding on said compression pawl (51) and opposing the recoil of said escape wheel (1) by subjecting said at least one compression pawl (51) to a buckling force when said escape wheel (1) tends to recoil . 16. Exhaust mechanism (200) according to claim 2 or 3 or one of claims 4 to 13 when dependent on claim 2, characterized in that said non-return device (5) comprises at least one ratchet of traction device (52) comprising a second elastic connection with a second fixed part of said exhaust mechanism (200) external to said stopper (2) and said escape wheel (1), said at least one pulling pawl (52) co-operating with said at least one toothing (10) and arranged to operate in traction and exert on said escape wheel (1) a torque tending to advance it, when said escape wheel (1) tends to move back, said pawl of traction (52) being either constituted by said compression pawl (51) is constituted by a separate pawl. 17. Exhaust mechanism (200) according to claim 2 or 3 or one of claims 4 to 13 when dependent on claim 2, characterized in that said non-return device (5) comprises at least one ratchet of internal compression (53) comprising a third elastic connection with said escape wheel (1) and cooperating with a toothing (10) that comprises a toothed ring internally fixed on a fixed part of said exhaust mechanism (200) external to said stop ( 2) and said escape wheel (1). 18. Exhaust mechanism (200) according to one of claims 14 to 17, characterized in that said at least one toothing (10) periodically comprises, alternately with areas provided with teeth (11), areas devoid of teeth (12) for minimizing losses when the anti-return function is not necessary, when said polar mass (3) of said stopper (2) cooperates with a zone of zero potential of said track (4; 41, 42) or a low potential area of a said ramp (6). 19. Exhaust mechanism (200) according to claim 3 or 5, and according to one of claims 14 to 17, characterized in that said at least one toothing (10) comprises at least one tooth (13) on each said useful area (ZU). 20. Exhaust mechanism (200) according to claim 3 or 5, and according to one of claims 14 to 17, characterized in that said at least one toothing (10) comprises, on the zones provided with teeth that it comprises at least twenty times more teeth than said escape wheel (1) does not include said step (P), each said step (P) corresponding to the race between two successive tilts of said stop (2). 21. Exhaust mechanism (200) according to one of claims 1 to 20, characterized in that said non-return device (5) comprises at least one freewheel device. 22. A watch movement (300) comprising at least one escape mechanism (200) according to one of claims 1 to 21. 23. Watch (400) comprising at least one exhaust mechanism (200) according to one of claims 1 to 21.