EP1710636A1 - Escapement for a watch - Google Patents

Abstract

The mechanism has a roller (14) mounted on a balance (16) and including a pin (23) and a pallet (24) cooperating with an escape wheel (10). A pallet assembly includes an arm functioning as a balance course limiting unit and another arm functioning as a control unit to accomplish a periodic movement during which the wheel is liberated and provides an impulse to the pallet (24). Periods of the arms correspond to the alternation and oscillation of the balance.

Description

The present invention relates to the field of watchmaking. It relates more particularly to a mechanical watch mechanism known as an escapement.

The purpose of the escapement is to maintain and count the oscillations of the pendulum of a watch (or the pendulum of a clock). It receives the energy dispensed at the base by the barrel, through the finishing train, and lets periodically escape a parcel of this motive power to restore to the regulating organ that makes him lose the friction. The exhaust is a distributor member transforming the rotational movement of the gear train into a reciprocating movement. Many books have focused on describing the different exhaust mechanisms. We can refer to " Theory of Watchmaking "by Reymondin et al, Federation of Technical Schools, 1998, ISBN 2-940025-10-X, pages 99-128 .

The most common escapement is the Swiss anchor escapement, described in detail in the reference cited above. But a particular type of exhaust, known as a detent escapement, has a better mechanical performance. It appeared around the eighteenth century when maritime nations competed for the construction of the most accurate time instrument possible, allowing the safest determination of the geographical position at sea.

An expansion escapement is shown in FIG. 1. It comprises, in a conventional manner, an escape wheel 1 connected kinematically to the cylinder, and a trigger 2. A double plate 3 carries a pulse pallet 4 cooperating with the wheel of FIG. exhaust 1 and a release pallet 5 working with the end of the trigger 2. The latter has a bend, carrying a pallet rest 6, on which can come to rest the wheel 1. springs 7 and 8 allow to maintain the different supports.

This type of exhaust has certain disadvantages that make it particularly difficult to adapt in a wristwatch. In particular, it is sensitive to shocks. If a lateral shock disengages the rest pallet 6, the mechanism is racing. In addition, in case of amplitude of the pendulum exceeding 360 °, the escape wheel performs a double-jump, also called gallop. Finally, it is not self-starting. This means that when you raise the watch while it is stopped, it is necessary to launch the pendulum oscillating by printing a rapid rotational movement to the watch.

The object of the present invention is to propose an exhaust system benefiting from the mechanical efficiency of a detent escapement, without presenting the disadvantages thereof.

• une roue d'échappement reliée cinématiquement à une source d'énergie,
• un plateau monté sur un balancier comportant, sur deux niveaux différents, une cheville et une palette d'impulsion coopérant avec la roue d'échappement,
• un organe de limitation accomplissant un mouvement périodique au cours duquel il coopère avec la cheville pour limiter la course du plateau,
• un organe de commande muni d'une levée de repos accomplissant, à partir d'une position stable dans laquelle la roue d'échappement est appuyée sur la levée de repos, un mouvement périodique au cours duquel cette roue est libérée et donne une impulsion à la palette d'impulsion.

More specifically, the invention relates to an escapement for a mechanical watch comprising:

• an escape wheel kinematically connected to a source of energy,
• a plate mounted on a balance comprising, on two different levels, an ankle and a pulse pallet cooperating with the escape wheel,
• a limiting member performing a periodic movement during which it cooperates with the ankle to limit the travel of the plate,
• a control member provided with a rest lift which, from a stable position in which the escape wheel is resting on the rest lift, a periodic movement during which the wheel is released and gives a pulse to the pulse palette.

According to the invention, the periods of the limiting member and the control member correspond, respectively, to an alternation and an oscillation of the balance.

Advantageously, the limiting member is formed of a first arm pivotally mounted about an axis. It ends with a fork cooperating with the peg to move between a first and a second stable positions defined by a first and second stops. The limiting member further comprises a pulling system ensuring the maintenance of this arm in the first and second stable positions.

• d'un deuxième bras mobile en rotation en un point de pivotement et coopérant au moins médiatement avec le plateau pour quitter sa position stable, et
• d'un système de rappel pour ramener le deuxième bras à sa position stable après l'impulsion.

The control member is formed:

• a second arm movable in rotation at a pivot point and cooperating at least mediately with the plate to leave its stable position, and
• a return system to return the second arm to its stable position after the pulse.

In a first embodiment, the pulling member comprises a jumper and a pallet cooperating elastically with each other and arranged one on the first arm, the other on the second arm. This draw member makes the first and second arms integral when the second leaves its stable position.

Advantageously, the two arms are pivotally mounted around the same axis.

In a second embodiment, to make the second arm leave its stable position, the plate further comprises a release pallet. In addition, the second arm, on the one hand, carries an elastic member, whose end is intended to cooperate with the release pallet and, on the other hand, extends into a spout that ends so as to be contact laterally with the elastic member, near its end.

Advantageously, the spout crosses the elastic member and ends in a portion perpendicular to the plane of the arm.

In this second embodiment, the pulling system is magnetic or comprises a bistable spring cooperating with the first arm.

In a first variant in which the rest lift is arranged on a first side of the second arm with respect to its pivot point, the return system comprises a portion of the second arm disposed on the other side of the pivot point and a return pallet located on this portion and intended to cooperate with the escape wheel.

In a second variant, the return system is formed by edge planks associated with the teeth of the escape wheel and a return pin disposed on the second arm and intended to cooperate with the inner surface of the boards.

• la figure 2 est une vue en perspective d'un mécanisme d'échappement selon l'invention,
• les figures 3 à 8 représentent le cycle dudit mécanisme,
• la figure 9 est une vue en perspective d'un deuxième mode de réalisation selon l'invention,
• les figures 10 à 16 illustrent le cycle de ce deuxième mécanisme,
• la figure 17 est une variante du deuxième mode de réalisation.

Other details of the invention will emerge more clearly on reading the description which follows, made with reference to the appended drawing, in which:

• FIG. 2 is a perspective view of an escape mechanism according to the invention,
• FIGS. 3 to 8 represent the cycle of said mechanism,
• FIG. 9 is a perspective view of a second embodiment according to the invention,
• FIGS. 10 to 16 illustrate the cycle of this second mechanism,
• Figure 17 is a variant of the second embodiment.

In order not to overload the drawings, the bridges and the platen of the watch movement in which the exhaust mechanism according to the invention takes place have not been shown. It is obvious that the various mobiles pivot on their axes arranged in stones or other bearings that the skilled person knows perfectly, without the need to describe them.

First embodiment

FIG. 2 shows an escapement wheel 10 kinematically connected to the barrel (not shown) of a mechanical watch movement. This wheel 10 is provided with teeth 12 intended to cooperate, on the one hand, with a plate 14 mounted on a rocker 16 and, on the other hand, with an anchor 18.

The teeth 12 have, in particular, a plane BC which, as the description below will explain, acts as a rest plane and pulse plane, and a plane AB, the intersection of the planes defining the tip of the teeth.

The plate 14 has two levels, one lower 20 and the other upper 22, mounted coaxial. The lower level receives a pulse pallet 24, while an ankle 23 is disposed on the upper level 22.

The anchor 18 is provided with a first arm 26 pivoted about an axis AA, acting as a limiting member of the stroke of the balance 16. It is of bent shape and ends with a fork 28, similar to that of a Swiss lever escapement and comprising, in particular, an inlet 28a and an outlet 28b and a stinger 28c (visible in Figures 3 to 17). Its stroke is limited by two fork stops 29, arranged on either side of the arm 26. The fork 28 cooperates with the peg 23 of the level 20.

The anchor 18 further comprises a second arm 30 pivotally mounted with reference to the first arm, also around AA. This arm acts as a control member because, as will be understood below, it releases and stops the escape wheel 10. The pivot point separates the arm 30 into a resting portion 30a and a second 30b called recall.

The rest portion 30a has, at its end and on its lower face, a rest lift 32 intended to cooperate with the teeth 12 of the escape wheel 10. It is also provided on its upper face with a pallet bearing 34 whose role will appear later and an opening 36 inside which is housed a stop 38. This limits the stroke of the arm 30.

The return portion 30b ends with a return pallet 40 intended to cooperate with the teeth 12. These elements form a return system whose operation is explained below. In addition, this part acts as a counterweight for the part 30b and thus facilitates the pivoting of the arm 30 in the vertical positions of the mechanism.

The arms 26 and 30 are interconnected by a jumper 44 cooperating with a wire spring 46. The jumper is mounted slightly pivotally in the elbow of the arm 26 and has a lug 48 near its pivot point. Its end cooperates with the pallet 34 and is shaped so as to provide two surfaces 44a and 44b of stable support on the pallet 34 which, in addition, plays the role of pulling system. The spring 46 is mounted on the arm 26 and acts on the lug 48 to support the jumper 44 against the pallet 34.

The operation of the mechanism is illustrated in Figures 3 to 8.

Figure 3

The exhaust is at rest and the balance is in the downward portion of its alternation and rotates counterclockwise (SIAM below). The peg 23 and the impulse pallet 24 are free. The first bearing surface 44a of the jumper 44 cooperates with the pallet 34. The escape wheel 10 is fixed, the plane BC of one of its teeth 12 resting on the rest lift 32. This causes a draw now the arms 26 and 30 of the anchor 18 in a first stable position, wherein the arms 26 and 30 are respectively supported on a first of the stops 29 and on a first side of the abutment 38. The pallet 40 of the arm recall 30b is set back from the escape wheel 10.

Figure 4

The rocker 16 continues its alternation and the ankle 23 comes into contact with the inlet 28a of the fork 28, as is the case with a Swiss lever escapement. The arm 26 is then rotated about the axis AA in the direction of clockwise (SAM below). Through the jumper 44 and the spring 46, the arm 30 is driven in the same movement. In this way, the constituent parts of the anchor 18 are integral.

Figure 5

The movement of the arm 30 causes the release of the escape wheel 10 which released its support on the lift rest 32. The wheel 10 then rotates in the SAM, kinematically driven by the barrel. The anchor 18 continues its pivoting movement around AA, always driven by the pin 23, which brings the pallet 40 of the return arm 30b into contact with a tooth 12.

Figure 6

The pallet 40 and the arm 30b are stopped in their movement. The arm 26 is completely independent and retains its initial movement in the SAM, still under the effect of the pin 23. As a result, the pallet 34 leaves the first bearing surface 44a of the jumper 44 and slides to the second 44b.

On the other hand, the plane BC of the tooth next to that which has just left the support pallet 34 comes into contact with the pallet 24 to give the impetus.

Figure 7

The peg 23 leaves the fork 28, and the pallet 24 leaves the tooth 12 so that the rocker 16 oscillates freely in the upward portion of its alternation. It is now the second bearing surface 44b of the jumper 44 which cooperates with the pallet 34. Under the effect of the jumper 44 passing from one to the other of its stable positions, the arm 30 is brought into its initial position, as shown in Figure 3. The surface 44b is oriented to generate a draw now the arms 26 and 30 of the anchor 18 in a second stable position, in which they are respectively supported on the second of the stops 29 and on the first side of the abutment 38. The escape wheel 10 is fixed, the tooth 12 which has just given the impulse resting on the rest lift 32. The pallet 40 of the return arm 30b is set back from the escape wheel 10.

Figure 8

The rocker 16 and the plate 14 turn in the SAM and are in the descending portion of their next alternation. The second surface 44b is always resting on the pallet 34 and the wheel 10 is fixed, resting on the rest lift 32.

The pallet 24 and the peg 23 continue their downward cycle and this latter comes into contact with the outlet 28b of the fork 28, thus bringing the anchor back to its initial position in FIG.

When the pendulum has completed this alternation, a new cycle as described above starts and so on.

Second embodiment

In Figure 9, the escape wheel 10 has a singing structure. More specifically, the plane AB of the teeth 12 of the escape wheel 10 is extended by a board 50 rising perpendicular to the plane of the wheel.

The plate 14 has a third level 52 superimposed coaxially at the level 22 and provided with a clearance pallet 54 visible in Figure 10. It ends with a point having a straight portion 54a and a portion in a circular arc 54b.

The limitation and control members are always formed arms 26 and 30 which are each pivotally mounted on independent axes, respectively BB and CC. The arm 26 has only the fork 28 and a magnet 55. The stops 29 are made of a soft magnetic material, the attraction of which with the magnet 55 ensures the draft which keeps the anchor in its first and second stable positions.

The arm 30 is comparable to the expansion of the exhaust mechanism of the same name shown in Figure 1. It is provided with a return pin 56 for cooperating with the inner surface of the boards 50 to provide the return system. It carries an elastic member formed of a spring 58 mounted rigid DC, substantially parallel to the longitudinal axis of its base. The end of the spring 58 is intended to cooperate with the release pallet 54 (visible in Figure 10) against the right portion 54a in alternation and against the circular portion 54b in the other half. The arm 30 is further extended into a spout 60. It passes under spring 58 and ends in a portion 62 rising perpendicularly to the plane of the arm 30 so as to be in lateral contact with the spring 58, near its end.

The operation of the mechanism is illustrated in Figures 10 to 16.

Figure 10

The exhaust is at rest and the balance 16 is in the downward portion of its alternation and rotates counterclockwise (SIAM below). The peg 23 and the impulse pallet 24 are free. The escape wheel 10 is fixed, resting on the rest lift 32, which pulls the arm 30 against the abutment 38.

The arm 26 is in its first stable position, magnetically held in abutment against a first of the stops 29.

The return pin 56 is free, above the serge of the escape wheel 10.

Figure 11

The impulse 24 and clearance paddles 54 and the pin 23 continue their downward cycle and the latter comes into contact with the inlet 28a of the fork 28. The arm 26 is then rotated about the axis BB in the SAT. Simultaneously, the pallet 54 meets the end of the spring 58, resting on the spout 60, which has the effect of putting the arm 30 in rotation in the SAM around the axis CC.

Figure 12

The release pallet 54 continues its rotation and pushes the spring 58, the nozzle 60 preventing the latter from being deformed. The movement of the arm 30 causes the release of the escape wheel 10 which is no longer in contact with the rest lift 32. The wheel 10 then rotates in the SAM, driven kinematically by the barrel. The arm 26 is always rotated around BB by the ankle 23.

Figure 13

The release pallet 54 continues its rotation and leaves the contact of the spring 58. The tooth 12 which has just left the rest lift 32 comes to rest, by its board 50, on the return pin 56. The force generated by this support causes the arm 30 in the SIAM, to bring it back to its original position.

Figure 14

The peg 23 continues its rotation and leaves the fork 28, the arm 26 being in the vicinity of the second stop 29.

The pin 56 is no longer supported on the board 50 of the tooth 12, but the arm 30 is not yet quite in its rest position.

On the other hand, the plane BC of the tooth next to that which has just left the support pallet 34 comes into contact with the pallet 24 of the level 20 to give the impetus.

Figure 15

The rocker 16 and the plate 14 complete their alternation in the SIAM. The peg 23 and the impulse 24 and clearance paddles 54 are free and are in the ascending portion of their alternation. The fork 28 is now in its second stable position, held magnetically in abutment against the second stop 29.

The arm 30 is returned to its rest position, as described in FIG.

The escape wheel 10 is fixed, the tooth 12 which has just given the impulse resting on the rest lift 32.

Figure 16

The rocker 16 and the plate 14 turn in the SAM and are in the descending portion of their next alternation.

During their downward cycle, the pin 23 comes into contact with the outlet 28b of the fork 28, bringing it back to the initial position of the FIG. 10. The circular portion 54b of the release pallet 54 raises the spring 58. The latter is slightly tensioned and resumes its rest position as soon as the pallet 54 has released.

The wheel 10 is fixed, resting on the rest lift 32.

When the pendulum has completed this alternation, a new cycle as described above starts and so on.

FIG. 17 illustrates a variant of this second embodiment, in which the arm 26 cooperates with a bistable spring 64, ensuring the maintenance of its first and second stable positions, resting against the stops 29. The passage from one to the other is always by interaction of the ankle 23 on the fork 28.

In the above examples and according to an important characteristic of the invention, the periods of the first arm 26 and the second arm 30 respectively correspond to an alternation and an oscillation of the balance 16.

The above examples are only illustrations of the invention. Thus, the return systems described in the two embodiments are compatible with both versions of the controller.

Claims (10)

Exhaust for a mechanical watch comprising: an escape wheel (10) kinematically connected to a source of energy, - a plate (14) mounted on a rocker (16) comprising, on two different levels, an anchor (23) and a pulse pallet (24) cooperating with said wheel (10), - a limiting member (26) performing a periodic movement during which it cooperates with said pin (23) to limit the travel of said plate (14), - a control member (30) provided with a rest lift (32), from a stable position in which said wheel (10) is supported on said rest lift (32), a periodic movement during from which said wheel is released and gives a pulse to said pulse pallet (24), characterized in that the periods of the limiting member (26) and the control member (30) respectively correspond to an alternation and an oscillation of said balance. Exhaust according to claim 1, characterized in that the limiting member is formed of a first arm (26) pivotally mounted about an axis (AA, BB), ending with a fork (28) cooperating with said pin (23) for moving between first and second stable positions defined by first and second stops (29), and a pulling system for maintaining said first arm (26) in said first and second stable positions. Exhaust according to claim 2, characterized in that the control member is formed: a second arm (30) rotatable at a pivot point, said second arm cooperating at least mediately with said plate (14) to leave its stable position, and - A return system for returning said second arm (30) to its stable position after the pulse. Exhaust according to claim 3, characterized in that the pulling member comprises a jumper (44) and a pallet (34) cooperating elastically with each other and arranged one on the first arm (26), another on the second arm (30) and in that it makes said first and second arm integral when said second arm (30) leaves its stable position. Exhaust according to one of claims 1 to 4, characterized in that said first (26) and second (30) arms are pivotally mounted about the same axis. Exhaust according to claim 3, characterized in that , to make said second arm (30) leave its stable position, said plate (14) further comprises a release pallet (54) and in that said second arm, on the one hand, carries an elastic member (58), whose end is intended to cooperate with said release pallet (54) and, on the other hand, extends into a spout (60) which terminates so as to be in lateral contact with said elastic member (58) near its end. Exhaust according to claim 6, characterized in that said pulling system is magnetic. Exhaust according to claim 6, characterized in that said pulling system comprises a bistable spring (64) cooperating with said first arm (26). Exhaust according to one of claims 3 to 8, wherein said rest lift (32) is disposed on a first side of said second arm (32) with respect to its pivot point, characterized in that said return system comprises a portion (30b) of said second arm (30) disposed on the other side of the pivot point and a return paddle (40) located on said portion and intended to cooperate with said escape wheel (10). Exhaust according to one of claims 3 to 8, characterized in that said return system is formed by edge plates (50) associated with the teeth (12) of said escape wheel and a return pin (56) arranged on said second arm (30) and intended to cooperate with the inner surface of the boards (50).

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