EP2450756B1 - Anti-tripping device for escapement mechanism - Google Patents

Description

Field of the invention

The invention relates to an anti-gallop device for an escapement mechanism arranged to cooperate with a rocker pivoting about a first axis of pivoting position fixed relative to a plate.

The invention also relates to an escapement mechanism comprising, pivotally movable with respect to a plate, at least one rocker pivoting about a balance shaft.

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 or / and at least one such escape mechanism.

The invention relates to the field of watchmaking, in particular the field of escape mechanisms, and more particularly the field of relaxation escapements.

Background of the invention

The trigger escapement mechanisms are considered the most accurate, and have long been reserved for marine chronometers.

Their efficiency is indeed greater than that of anchor escapements, because the escape wheel communicates an impulse to the rocker once per oscillation, during which the escape wheel pivots with an angular pitch. As a result, the energy loss of The inertia of the escape wheel occurs once by oscillation, as against once alternately on the anchor escapements.

Their use on wristwatches is more delicate, because of their vulnerability to shocks.

During shocks, particularly lateral, if the rocker is pivoted beyond its normal amplitude, a tooth of the escape wheel can leave the pallet rest, there are two clearances and two pulses during the same alternation this phenomenon called gallop has the effect of distorting the isochronism of the oscillator.

The patent EP 1 708 047 in the name of WATCHES BREGUET SA describes a rocker having an arm carrying both a first finger to cooperate with the second actuating finger, and a beaked probe cooperating with a notched cam similar to the previous. In a first pivoting direction of the balance and its trays, the first finger drives the second finger to disengage the pallets or rest of the escape wheel. The spout of the arm-probe is then driven by a rising edge of the notched cam, to re-engage the locking means in the escape wheel. When the rocker pivots in the opposite direction, the first finger drives the second finger to maintain the locking means engaged in the escape wheel. The meeting of the first and the second finger, whatever the pivoting direction of the trays, generates a rotating and natural force on the axis of the rocker. This meeting does not generate any risk of breakage of the mechanism. No elastic member or stop pin is required. In a particular embodiment, this mechanism comprises two juxtaposed rest palettes comprising contiguous but non-aligned resting planes, which makes it possible to accommodate the tip of the wheel tooth. exhaust on a line of rest at the junction of these rest planes, creating a pull effect to overcome any stop pin. The rest plan of the stopping pallet closest to the escape wheel is in effect before the tooth, and prevents him from continuing on his way. In this position of total rest of the tooth of the escape wheel, the beak of the arm-probe takes off from the periphery of the plate, and leaves full freedom to the balance to complete its first alternation. This construction makes the escapement resistant to shocks, indeed a shock brings the spout to the periphery of the corresponding plate, without however disengaging the pallets of rest, because the return of the tooth to the line of rest takes place immediately thanks to this pull effect. When, then, during the reverse movement of the balance in the opposite direction, towards the end of the second alternation, the first finger and the second finger come into cooperation, they give rise to a couple of the trigger rocker about its pivot axis, causing a slight recoil of the tooth of the escape wheel, before, during the separation of the fingers, the tooth returns to the line of rest in a counter-pulling effect.

The patent EP 1 708 046 on behalf of WATCHES BREGUET SA discloses a safety finger fixed on the balance plate, and arranged to cooperate with the teeth of the escape wheel and block if the pulse pallet was to be released by accident of the teeth of wheel. This arrangement prevents any panic of the escape wheel in the event of shock resulting in the reversal of the direction of rotation of the trays at the precise moment of the impulse of the wheel. The encounter of a tooth of the wheel with this safety finger blocks the wheel, brings back the trays in the correct direction of rotation.

The document EP 1,522,001 in the name of Detra SA and Patek Philippe SA offers an exhaust mechanism with locking parts and toothed wheels with tooth gaps. A first mobile is subjected to a periodic torque, obtained for example by a rotor mounted in a stator. This first mobile comprises, firstly in a base plane a first wheel having teething gaps on its periphery, and secondly on a second plane a first blocker having a plurality of fingers and adapted to block a release lever that includes a balance plate, in a first pivoting direction of this last. This first mobile cooperates, depending on its position, either by the first blocker, or by its first wheel, with a second mobile. This second mobile comprises, in the base plane, a second wheel having teething gaps, in the second plane a shaped piece having a plurality of fingers and adapted to lock the release lever of the balance plate, in a second pivoting direction. opposed to the first, and the second mobile further comprises, in a first plane parallel to the previous plans a locking piece. This second mobile cooperates, depending on its position, either by the locking piece or by its second wheel, with an escape wheel, which comprises, in the base plane, a toothed wheel having teething gaps, and in the first plan impulse wheel receiving a continuous mechanical torque such as that of a cylinder, similar to a conventional escape wheel, and adapted to cooperate with a lever pulse that includes the balance plate, to maintain the movement of oscillation of this denier. According to the respective angular positions of the different mobiles, the locking pieces, or of shape, or the teeth, cooperate with each other, so that the device has, for each revolution of rotation of the first axis, four stable locking positions, between which it has so many unlocking positions. The combination of two locking means and two means of unlocking the mechanical torque, and the particular sequence imposing an unlocking operation between two blocking operations realize the prevention of any runaway or gallop in case of impact on the mechanism. Such a mechanism is complex, relatively expensive, and unfolds in several planes, which makes its thickness significant.

The patent application EP 1 770 452 in the name of Baumberger Peter is an improvement of the patent Voigt US 180,290 , designed to minimize the bulk, and describes a conventional expansion exhaust with a detent rocker pivoted and recalled by a spiral spring, an arm of this rocker carries one end of a leaf spring whose other end is held in support on a stop carried by another arm of the flip-flop, and is arranged to cooperate with a release pallet secured to a small balance plate. Another arm of the rocker, beyond a pallet of rest, comprises a finger which cooperates with the periphery of this small plate, and in particular with a truncated portion making cam, at a lower level than that of the leaf spring . A large platform of the balance typically carries a pulse pallet, preceded by a first recess, and followed by a second recess, to allow the release of the pallet rest when the release pallet rotates the trigger rocker. The choice of a particular geometry, both in terms of the positioning of the pallet of rest and the pallet of impulse in quasi-symmetry of the line of the centers of the escape wheel and the pendulum during the phase of rest, which 'at the fork formed by the finger and the free end of the leaf spring, limit the disruptive effect related to the inertia of the trigger on the pendulum oscillations. The amplitude of the pivoting movements of the trigger, in case of shock, is limited by the interaction of the pallet rest and large plateau. In a complementary embodiment, this mechanism comprises an anti-gallop rocker, in the vicinity of the small plate, pivotally mounted on the movement between two stable end positions held by a jumper on stops with which can cooperate a first end, and a fork-shaped second end interacts with the release pallet: at each passage through the fork, the release pallet exerts pressure to tilt the anti-gallop rocker from one to the other of its stable positions. The fork is thus two stops for the small plateau in case of galloping, and prevents the pendulum to do more than one turn in pivoting.

The document EP 1 860 511 in the name of Christophe Claret SA describes a moving bridge movement, providing protection against side impacts of a detent escapement. This movable bridge carries the pivot axis of the sprung balance, the pivot axis of the escape wheel, the pivot axis of the trigger, and a part of the finishing gear. It is rotated elastically on the axis of one of the wheels of the cogwheel finishing, for example the second wheel. Forces, such as a side impact, capable of disengaging the pallet of rest, then drive the movable bridge in its entirety, and the relative positions of the trigger and the escape wheel are maintained. Thus, a constant step of the exhaust is ensured. This movable bridge can, again, be damped by a damping system that allows to dissipate some of the energy due to impact.

The patent application CH 700 091 in the name of Christophe Claret SA describes a detent escapement, with a trigger rocker pivotally mounted on a spiral spring and cooperating at the other end with a first recessed spring blade in the vicinity of the pivot. The balance plate has two separate pallets. A movable member disposed on the opposite side of the escape wheel, relative to the trigger rocker, carries a pivoting cam, holding a cam spring blade, and biased toward the trigger by a spiral spring at a stop position. This cam is arranged to cooperate the cam spring-blade, or in a first state with the end of the load-bearing latch of the leaf spring, or in a second state with the pallets of release of the balance. The first release pallet is arranged to cooperate with the first leaf spring and operate the trigger when the first paddle crosses the first blade in a first direction, and to cooperate only with the first blade and without actuating the trigger when it crosses in the opposite direction. The cam, in its first state, cooperates with the trigger to limit the movements thereof. The second clearance pallet is arranged to move the cam into its second state where the trigger is free to perform its release and release the exhaust wheel tooth of the pallet rest. The two clearance pallets are close together, and arranged in such a way that the cam is brought into its second state just before the detent makes its release. The spiral return cam spring, stronger than the cam spring blade, tends to return the cam to its first state. Thus, the cam, in its first state, is positioned to oppose everything inadvertent movement of the trigger that would result in an untimely release of the pallet rest, and the exhaust is less sensitive to the effects of a shock. The adjustment of this mechanism is difficult because it depends on the characteristics of the springs it comprises, the number of at least three.

The patent application EP 2,224,292 in the name of Rolex SA discloses a direct impulse escapement, including expansion. Its trigger rocker is arranged in a particular way, pivoting between two stops, it has, turned towards the escape wheel, a finger successively comprising a stop surface serving as a pallet of rest, a safety surface which, depending on the position of pivoting of the rocker, interferes or not with the trajectory of the escape wheel, and a sliding surface which forces the rocker to tilt, during the pivoting of the escape wheel, in order to reduce the sliding surface and therefore the stop surface in the interference zone with the escape wheel to stop the pivoting thereof. The balance plate conventionally comprises a pulse pallet and a release finger. During the alternation in a first pivoting direction of the balance, the rocker is in a first pivoted position in abutment which leaves the passage to the release finger, while in the other alternation in the other direction of pivoting, the pivoted rocker in another abutment position encounters, at a resilient clearance element that it comprises, the release finger. The elastic travel of this resilient release member allows the balance to continue its course, the pulse pallet passes between two adjacent teeth of the escape wheel. Shortly afterwards, the balance is stopped by its spring-spiral and pivots in opposite directions. During this elastic race, the rocker remains braced on its stop, and the stop surface of the rocker slides on the tooth of the escape wheel that keeps it in stop. The safety of this mechanism is ensured by the arrangement of the finger of the rocker, with a stop surface and a sliding surface which penetrate alternately in the path of the toothing of the escape wheel. The length of the safety surface between the stop surface and the sliding surface corresponds to the angle traveled by the wheel to communicate the driving energy to the balance, to prevent the premature return of the stop element in the path of the wheel , which constitutes a complementary security. Part of the energy of the cylinder is however consumed in friction during the sliding phase.

Few patent documents are specifically dedicated to anti-gallop mechanisms.

The document EP 1 645 918 in the name of MONTRES BREGUET SA describes such a mechanism, comprising a finger fixed on an arm of the balance. The balance bridge has two columns, between which can pass this finger. A locking arm is fixed on the outer turn of the spiral, in particular by pinching, and is likely, when the pendulum tends to pack under the effect of a shock, and exceed its normal amplitude, to come in support on the columns to prohibit the passage of the finger.

The document EP 1 801 668 in the name of WATCHES BREGUET SA discloses the equipment of the balance shaft with a pinion, which cooperates with a toothed sector movable between two stop positions and preventing the balance to pivot beyond its normal amplitude.

In short, the known realizations are often complex, and difficult to transpose from one escape mechanism to another. The stop mode of the balance is usually very abrupt, and does not always guarantee a restart of the movement without intervention.

Summary of the invention

The invention proposes to overcome the shortcomings of the prior art, by proposing a mechanism that is both simple and reliable, inexpensive, and easily adaptable to existing exhaust mechanisms.

For this purpose the invention relates to an anti-gallop device for an escapement mechanism arranged to cooperate with a rocker pivoting about a first axis of pivoting of fixed position relative to a plate, characterized in that said device comprises, movable pivoting about a second pivot axis parallel to said first axis of pivoting and fixed position relative to said plate, a pivoting mobile having a guide means, said device also comprising a plate arranged to be fixed to said pendulum solidarity pivoting with it, said plate comprising a complementary guiding means arranged to cooperate with said guide means, and further characterized in that said guiding means, or respectively said complementary guiding means, comprises a cam with a cam track, said cam arranged to bring said pivoting mobile to said first pivot axis when said balance pivots in a first pivoting direction, and for moving said pivoting mobile member away from said first pivot axis when said rocker pivots in a second pivoting direction opposite to said first pivoting direction, while said complementary guide means, or said guide means, respectively, comprises a fixed finger arranged to cooperate with said cam.

According to a characteristic of the invention, said cam is limited by a first limit stop near the axis of pivoting of the component which carries said cam, and by a second limit stop further away than said first stop. end of travel of the pivot axis of the component carrying said cam, so as to immobilize said balance when reaching said first limit stop or said second limit stop.

According to another characteristic of the invention, said complementary guiding means comprises a cam track arranged with a radially increasing radius, or with an increasing radius with radial growth levels, around said first axis. pivoting means and said guide means comprises a finger pin arranged to cooperate with said cam track.

The invention also relates to an escapement mechanism comprising, pivotally movable relative to a plate, at least one rocker pivoting about a balance shaft, characterized in that it is a trigger escapement mechanism, and in that it comprises such an anti-gallop device, said pivoting mobile is pivotally mounted about a second pivot axis parallel to said first axis of pivoting and fixed position relative to said platen.

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 oulet at least one such escapement mechanism.

Brief description of the drawings

• la figure 1 représente, de façon schématisée et en perspective, un
  dispositif anti-galop selon l'invention, dans une position de repos, associé à un balancier et à une platine non représentée ;
• la figure 2 représente, de façon schématisée et en vue de face, le dispositif anti-galop de la figure 1, dans la même position ;
• la figure 3 représente, de façon schématisée et en vue de face, le dispositif anti-galop de la figure 1, dans une première position de fin de course;
• la figure 4 représente, de façon schématisée et en vue de face, le dispositif anti-galop de la figure 1, dans une deuxième position de fin de course opposée à la précédente;
• la figure 5 représente, de façon schématisée et en vue de face, un plateau que comporte un dispositif anti-galop selon l'invention, dans une autre variante de réalisation ;
• les figures 6 et 7 représentent, de façon schématisée, partielle et en vue en plan, l'aménagement, dans un mode de réalisation particulier, du voisinage de surfaces de butée que comportent, respectivement, un plateau de balancier et un mobile pivotant que comporte le dispositif anti-galop selon l'invention.

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

• the figure 1 represents, schematically and in perspective, a
  anti-gallop device according to the invention, in a rest position, associated with a rocker and a plate not shown;
• the figure 2 represents, schematically and in front view, the anti-gallop device of the figure 1 in the same position;
• the figure 3 represents, schematically and in front view, the anti-gallop device of the figure 1 in a first end position;
• the figure 4 represents, schematically and in front view, the anti-gallop device of the figure 1 in a second end position opposite to the previous one;
• the figure 5 represents, schematically and in front view, a plate that comprises an anti-gallop device according to the invention, in another embodiment;
• the Figures 6 and 7 show schematically, partially and in plan view, the arrangement, in a particular embodiment, the vicinity of abutment surfaces that comprise, respectively, a balance plate and a pivoting mobile that includes the anti-gallop device according to the invention.

Detailed Description of the Preferred Embodiments

The invention relates to the field of watchmaking.

The invention relates to an anti-gallop device 1 for escape mechanism 10, which is arranged to cooperate with a balance 2 pivoting about a first pivot axis D1 fixed position relative to a plate.

According to the invention, the device 1 comprises, pivotally movable about a second pivot axis D2 parallel to this first pivot axis D1, and fixed position relative to the plate, a pivoting mobile 5.

This mobile 5 comprises a guide means 7, which is arranged to cooperate with a complementary guide means 9 that comprises a plate 3 arranged to be fixed to the rocker 2 integrally pivotally with it.

The guiding means 7, or respectively the complementary guiding means 9 in another embodiment, comprises a cam, which is arranged to bring the pivoting mobile 5 to the first pivot axis D1 when the rocker pivots in a first pivoting direction. B1, and to move the pivoting mobile 5 away from the first axis of pivoting D1 when the rocker pivots in a second pivoting direction B2 opposite the first pivoting direction B1.

The complementary guiding means 9, or respectively the guiding means 7 comprises a fixed finger arranged to cooperate with the cam.

In the preferred embodiment, illustrated by the figures, and explained in detail below, the cam is carried by the plate 3 fixed to the rocker 2. But the reverse configuration is also feasible.

The cam is limited on either side, firstly by a first limit stop 11 close to the pivot axis of the component carrying the cam, and secondly by a second end stop stroke 12 more distant than the first limit stop of the pivot axis of the component carrying the cam, so as to immobilize the balance 2 when reaching the first limit stop 11 or the second end stop 12.

In a position where the rocker 2 is in abutment upon reaching the first end stop 11 or the second end stop 12, the tangent T to the median profile of the cam at the first stop end of stroke 11, as well as at the second end stop 12, passes through the axis of pivoting of the component which carries the cam, so as to block the pivoting of the balance 2 about its pivot axis D1. In the embodiment of the figures, the guiding means 7 is a mobile pin 71, which runs along a cam track 91 of the cam 9, constituted by a groove formed in the plate 3.

The tangent T thus passes through the axis 4 which constitutes the pivot of the mobile pivot 5 along the pivot axis D2, as visible on the Figures 3 and 4 .

This particular arrangement makes it possible to pass through this axis the direction of the vector of the force exerted by the rocker abutting on the pin of mobile 71 by means of one of the two end stops. race 11 or 12, and thus to create a zero torque on the pivoting mobile 5, while blocking the pivoting of the balance 2, thus preventing it from performing any additional revolution in case of shock.

Preferably, the complementary guide means 9 comprises a cam track 91 arranged with a radially increasing radius, or with an increasing radius with radial growth bearings, around the first pivot axis D1, and the means 7 comprises a pin 71 forming a finger arranged to cooperate with the cam track 91.

To minimize friction, the pin 71 is movable with a radial clearance J in the cam track 91. A tribological surface treatment at the cam track 91 and / or the pin 71 further advantageously makes it possible to reduce these losses. friction. Indeed, the anti-gallop device 1 is of interest only in case of shock and runaway balance 2. In normal operation, that is to say in a rest position where the pin 71 occupies an intermediate position between the stops 11 and 12, as visible on the figure 1 or 2 the anti-gallop device 1 must consume as little energy as possible.

In a particular embodiment, as visible on the Figures 1 to 4 the cam has a cam track 91 spiraling about the first pivot axis D1.

Advantageously, this spiral is dimensioned and positioned relative to the pivot axis D2 so that a line joining the second pivot axis D2 to an axis 72 that includes the guide means 7 is tangent to the average profile. of the spiral in any position of the guide means 7.

In another particular embodiment, as visible on the figure 5 the cam comprises a cam track 91 comprising a plurality of circular sectors of revolution about the first pivot axis D1, connected in pairs by a transition zone 13 with a radially increasing radius. The figure 5 thus shows two zones of respective radii R1 and R2. It is understood that, when the pin 71 runs through these sections of revolution about the pivot axis D1, it is not subjected to any radial forces, and friction losses are minimal or even zero.

Advantageously, the pivoting wheel 5 comprises a balancing zone 8, which is preferably arranged to dynamically balance the pivoting wheel 5 around the second pivot axis D2, up to a maximum angular speed of rotation determined by the angular velocity pivoting of the balance 2 about the first pivot axis D1 on the one hand, and secondly by the combination between a first constant lever arm constituted by the distance between the second pivot axis D2 to an axis 72 that comprises the guide means 7 and a second variable lever arm constituted by the distance between the first pivot axis D1 to the axis 72. In an alternative embodiment, the balancing zone 8 is defined by a simple static balancing.

Preferably, for reasons of lightness, good elasticity, and ease of production, the pivoting mobile 5 and / or the plate 3 is made of a micro-machinable material, or silicon, or quartz, or one of their compounds, or an alloy derived from MEMS technology, or an alloy as obtained by the DRIE or "LIGA" method, or an at least partially amorphous material. To improve the resistance to shocks, the areas of the pivoting mobile 5 and the plate 3 subjected to shocks in case of runaway balance can be arranged, as visible on the Figures 6 and 7 .

So the plateau 3 of the figure 6 comprises, in the vicinity of each of the first limit stop 11 and second limit stop 12, at least one chamber 14 defining at least one elastic partition 15 arranged to cash the tangential force during an impact, and prevent thus any deterioration of the structure concerned, or comprises, as shown, a plurality of such chambers 14, emerging or not, defining elastic partitions 15 arranged to cash the tangential force during impact.

The figure 7 shows the end of an arm 6 that comprises the pivoting mobile 5. This arm 6 is similarly equipped with at least one chamber 14 defining at least one elastic partition 15 arranged to cash the tangential force when a shock, or a plurality of such chambers 14 defining resilient partitions 15. In this figure, the mobile pin 71 is shown fixed in a groove 73, which may include pre-machined housings to adapt the positioning of the pin 71 according to the exhaust on which the pivoting mobile 5 is installed, and according to the plate 3 used.

In variants not shown in the figures, such elastic partitions can be arranged also in the vicinity of the center of the spiral, or on the actual finger.

In a variant not shown in the figures, the swivel mobile 5 comprises an arm with a flip-flop, where the holding in each of the two stable positions is ensured, either by the cooperation of a notch with an elastic return means such as a spring, either by the cooperation of the magnet with another magnet or a pallet of magnetic material such as soft iron, or the like.

The pivoting mobile can thus be on an elastic pivot, and comprise a bistable elastic blade, for example with two concave spokes, to define two stable positions.

The invention also relates to an escapement mechanism 10 comprising, pivotally movable relative to a plate, at least one rocker 2 pivoting about a balance shaft D1. Preferably, this mechanism 10 is a trigger escapement mechanism, and it comprises an anti-gallop device 1 according to the invention, whose pivoting mobile 5 is pivotally mounted about a second pivot axis D2. parallel to the first pivot axis D1 and fixed position relative to the platen.

In a particular embodiment, the plate 3 is made in one piece with the balance 2.

In an advantageous embodiment of this escapement mechanism 10, the assembly consisting of the rocker 2 and the plate 3 is preferably monobloc, and is made of a micro-machinable material, or silicon, or quartz or one of their compounds, or an alloy derived from MEMS technology, or an alloy as obtained by the DRIE or "LIGA" method, or an at least partially amorphous material. This assembly can also be made in one piece with a spiral spring, as described in the European patent application. EP 2 104 008 in the name of the plaintiff.

The invention also relates to a watch movement comprising at least one such escape mechanism 10.

The invention also relates to a timepiece comprising at least one such watch movement, and / or at least one such exhaust mechanism 10.

The invention thus offers a reliable solution, very easy to implement, which has the advantage of being applicable to any existing expansion escapement model at the cost of minor modifications consisting in the fixing of a plate on the balance shaft, and the attachment of a mobile pivoting on the plate.

Claims (16)

1. Anti-trip device (1) for an escape mechanism (10) arranged to cooperate with a balance (2) pivoting about a first pivot axis (D1) whose position is fixed relative to a plate, said device (1) including a pivoting wheel set (5), pivotally moveable about a second pivot axis (D2) parallel to said first pivot axis (D1) and in a fixed position relative to said plate, said pivoting wheel set (5) including guide means (7), characterized in that said device (1) also includes a roller (3) arranged to be secured to said balance (2) and to pivot integrally therewith, said roller (3) including complementary guide means (9) arranged to cooperate with said guide means (7), said guide means (7), or respectively said complementary guide means (9), including a cam with a cam track (91), said cam being arranged to move said pivoting wheel set (5) closer to said first pivot axis (D1) when said balance is pivoting in a first direction of pivoting (B1), and to move said pivoting wheel set (5) away from said first pivot axis (D1) when said balance is pivoting in a second direction of pivoting (B2) opposite to said first direction of pivoting (B1), whereas said complementary guide means (9), or respectively said guide means (7) includes a fixed finger arranged to cooperate with said cam.
2. Anti-trip device (1) according to the preceding claim, characterized in that said cam is limited by a first limit stop member (11) in proximity to the pivot axis of the component that carries said cam , and by a second limit stop member (12) further away than said first limit stop member from the pivot axis of the component which carries said cam , so as to immobilise said balance (2) when said first limit stop member (11) or said second limit stop member (12) is reached.
3. Anti-trip device (1) according to any of the preceding claims, characterized in that said complementary guide means (9) includes a cam track (91) arranged with a radius that increases radially or with a radius that increases with radially increasing steps, about said first pivot axis (D1), and in that said guide means (7) includes a pin (71) forming a finger and arranged to cooperate with said cam track (91).
4. Anti-trip device (1) according to the preceding claim, characterized in that said pin (71) can move with a radial play (J) in said cam track (91).
5. Anti-trip device (1) according to claim 3 or 4, characterized in that said cam includes a cam track (91) in a spiral about said first pivot axis (D1).
6. Anti-trip device (1) according to the preceding claim, characterized in that a straight line joining said second pivot axis (D2) to an arbour (72) comprised in said guide means (7) is tangential to the median profile of said spiral in any position of said guide means (7).
7. Anti-trip device (1) according to claim 3 or 4, characterized in that said cam includes a cam track (91) including several circular sections of revolution about said first pivot axis (D1) connected in pairs by a transition zone (13) whose radius increases radially.
8. Anti-trip device (1) according to any of the preceding claims, characterized in that said pivoting wheel set (5) includes a balancing zone (8).
9. Anti-trip device (1) according to claim 2, characterized in that said roller (3) includes, in proximity to each of said first limit stop member (11) and second limit stop member (12), at least one chamber (14) defining at least one elastic partition (15) arranged to absorb tangential stress in the event of a shock.
10. Anti-trip device (1) according to any of the preceding claims, characterized in that said pivoting wheel set (5) includes, in proximity to said guide means (7), at least one chamber (14) defining at least one elastic partition (15) arranged to absorb tangential stress in the event of a shock.
11. Anti-trip device (1) according to any of the preceding claims, characterized in that said pivoting wheel set (5) and/or said roller (3) is made of silicon, or quartz, or a compound thereof, or of an at least partially amorphous material.
12. Escape mechanism (10) including at least one balance (2), pivotally moveable relative to a plate and pivoting about a balance axis (D1), characterized in that the mechanism is a detent escape mechanism, and in that it includes an anti-trip device (1) according to any of the preceding claims, wherein said pivoting wheel set (5) is mounted to pivot about a second pivot axis (D2) parallel to said first pivot axis (D1) and in a fixed position relative to said plate.
13. Escape mechanism (10) according to the preceding claim, characterized in that said roller (3) is made in a single piece with said balance (2).
14. Escape mechanism (10) according to the preceding claim, characterized in that said unit formed of said balance (2) and said roller (3) is made of silicon, or quartz or a compound thereof, or of an at least partially amorphous material.
15. Timepiece movement including at least one escape mechanism according to any of claims 12 to 14.
16. Timepiece including at least one timepiece movement according to the preceding claim 16 and/or at least one escape mechanism according to any of claims 12 to 14.

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