EP1544689B1 - Detent escapement for watches - Google Patents

Abstract

The escapement has a large roller (4) with a finger that drives a finger of a blocking unit (6) to release or lock a locking pallet-stone from or with an escapement wheel based on roller rotation. An impulse on a balance on which the roller is fixed is initiated when the roller rotates. The finger of the unit is driven by a rising flank of a notch of a small roller for re-engaging the pallet stone in the wheel.

Description

The present invention relates to a detent escapement for a timepiece comprising an escape wheel provided with teeth, a balance wheel on the axis of which are fixed a large plate equipped with a pulse pallet and a first actuating finger and a small plate on the circular periphery of which a notch is made, and a wedge-shaped blocker articulated on an axis, this blocker carrying a locking device of the escape wheel and a second actuating finger .

A detent escapement broadly in line with the above description has already been proposed and described in the old Swiss patent CH-3299 due to Emile James. The proposed arrangement shows a trigger-rocker pivoted at one of its ends according to a conventional construction of this kind of exhaust. The axis of the balance carries a large plate, a first small plate carrying a notch and a second small plate carrying an actuating finger. The weighing lever has a locking device for the escape wheel - in this case a pallet of rest -, a pin, a spout and a leaf spring. The trigger-rocker is brought to rest by a spiral return spring. As the actuating finger lifts the trigger with the leaf spring, the nose enters the notch at the same time as the escape wheel advances one step. During the additional arc, the beak is clear of the notch and is near the circular periphery of the first small plateau.

This arrangement has the advantage of preventing a tooth of the wheel from leaving the pallet rest when the timepiece receives a shock. At this time indeed, the spout is pressed briefly against the circular periphery of the first small plate, which stops the trigger-rocker which is immediately returned to rest by the spiral spring return.

What has just been said points to a weakness affecting the detent escapement, namely that of being sensitive to shocks, so this escapement is reserved especially for large chronometers or marine chronometers little solicited mechanically, this exhaust has the reputation of not being well suited to wristwatches.

In the proposed Swiss patent cited, however, it is noted that the extraction of the beak out of the notch is possible only through the spiral spring which exerts a return force on the trigger-rocker. Indeed, the notch has abrupt, almost radial flanks preventing any exit of the beak that would be caused by the only rotation of the plate itself.

Another escapement with a relaxation partially corresponding to the description of the first paragraph of this text was proposed by Breguet and is the object of an illustration (figure 402) published in the book of George Daniels entitled the Art of Breguet (London 1975). It is a revolving stopwatch escapement using a rocker blocker pivoted on an axle. A branch of the rocker is equipped with a pallet of rest cooperating with the teeth of the escape wheel. The other branch cooperates with a spring device mounted on the plate secured to the balance. This spring device is a very short blade capable both to actuate the latch when the plate rotates in one direction and to remain without effect on said latch when the plate rotates in the opposite direction. We thus find there the principle of any escapement with expansion in which the impulse to the balance is given only once oscillation during which the escape wheel progresses of an angular step while, in the escapement with anchor said wheel advances by half a step at each alternation. Here, one of the advantages of the detent escapement is measured since the energy lost as a result of the inertia of the escape wheel only occurs once per oscillation instead of once alternately.

It has been said above that the detent escapement is suitable for large timepieces which make it possible to have large balance wheels with a large reserve of energy and a high torque for actuating the elastic member acting on the trigger. . During an alternation indeed, it is necessary to stretch the elastic member to release the pallet rest, while the following alternation it is necessary to relax the same elastic member to cause it to bypass the trigger which is then not operated.

The object of the present invention is to propose a timepiece of small dimensions, for example a wristwatch that is equipped with a detent escapement to replace, for example, the classic anchor escapement and to benefit from the advantages conferred by this escapement relaxation. However, it will be understood that using the prior art techniques known and described above would lead to a failure since the energy developed by the pendulum of a wristwatch is much lower than that developed by a chronometer-watch, this pendulum thus showing itself unable to defeat the forces acting on the trigger.

Thus, the expansion escapement of the present invention is remarkable in that there is no elastic member acting on the trigger. For this purpose, the detent escapement of the invention, in addition to meeting the definition of the first paragraph of this description, is characterized in that the first and second actuating fingers are shaped in such a way that when the large and small trays rotate in a first direction, the first finger causes the second finger which bypasses a first side said first finger to disengage the locking device of the escape wheel, the second finger being then driven by a rising edge which is provided with the notch of the small plate to reengage the locking device in the escape wheel, and such that when the large and small trays rotate in a second direction, opposite the first direction, the first finger causes the second finger which bypasses a second side, opposite the first, of said first finger to maintain the engagement of the locking device in the escape wheel.

• la figure 1 est une vue en plan d'un premier mode d'exécution de l'échappement selon l'invention,
• la figure 2 est une vue en perspective de l'échappement montré en figure 1,
• la figure 3 est un agrandissement de la zone III de la figure 2,
• les figures 4 à 13 sont des vues en plan explicitant plusieurs phases de fonctionnement de l'échappement selon l'invention,
• la figure 14 est une vue en plan d'un deuxième mode d'exécution selon l'invention,
• la figure 15 est une vue en perspective de l'échappement montré en figure 14,
• la figure 16 est un agrandissement de la zone XVI de la figure 15,
• la figure 17 est une vue en plan d'un troisième mode d'exécution de l'invention,
• la figure 18 est une vue en perspective de l'échappement montré en figure 17, et
• la figure 19 est un agrandissement de la zone XIX de la figure 18.

The invention will now be explained in detail below by several embodiments given by way of example, these embodiments being illustrated by the appended drawings in which:

• the figure 1 is a plan view of a first embodiment of the escapement according to the invention,
• the figure 2 is a perspective view of the exhaust shown in figure 1 ,
• the figure 3 is an enlargement of zone III of the figure 2 ,
• the Figures 4 to 13 are plan views explaining several operating phases of the escapement according to the invention,
• the figure 14 is a plan view of a second embodiment according to the invention,
• the figure 15 is a perspective view of the exhaust shown in figure 14 ,
• the figure 16 is an enlargement of the XVI zone of the figure 15 ,
• the figure 17 is a plan view of a third embodiment of the invention,
• the figure 18 is a perspective view of the exhaust shown in figure 17 , and
• the figure 19 is an enlargement of the XIX zone of the figure 18 .

The Figures 1 to 3 illustrate the escapement relaxation object of the present invention according to a first embodiment. The exhaust comprises an escape wheel 2 provided with teeth 3. Without being shown in the drawings, the escape wheel is driven by the wheel of the timepiece which receives its driving force from a cylinder. On the axis 16 of the balance (not shown) is fixed a large plate 4 which is equipped with a pulse pallet 5 and a first actuating finger 14. On the same axis 16 is fixed a small plate 23 with a circular periphery 24 and a notch 22. The figures also show that the exhaust comprises a blocker 6 in the form of rocker hinged on an axis 8. The blocker 6 carries a locking device or a pallet 7 and a second finger actuator 11.

As has been said above, the detent escapement of the present invention is remarkable in that there is no elastic member acting on the blocker or trigger 6. To achieve this result, the Figures 1 to 3 show a particular configuration of the first and second actuating fingers 14 and 11. Because of this, when the large and small plates 4 and 23 rotate in a first direction, the first finger 14 drives the second finger 11 bypassing a first side 20 of said first finger 14, which has the effect of clearing the pallet 7 of the rest of the escape wheel 2 and initiate a pulse on the pendulum. The second finger 11 is then driven by a rising edge 25 which is provided with the notch 22 of the small plate 23, which has the effect of reengaging the pallet rest 7 in the escape wheel 2. Similarly the first and second actuating fingers 14 and 11 are shaped such that, when the large and small trays 4 and 23 rotate in a second direction b, opposite to the first, the first finger 14 drives the second finger 11 bypassing a second side 21 , opposite the first, of said first finger 14, which has the effect of maintaining the engagement of the pallet rest 7 in the escape wheel 2.

As we recalled above, we find here the principle of the escapement trigger in which the impulse to the balance is given only once per oscillation. It has just been seen that the escape wheel is released when the trays rotate in one direction while it remains blocked when these trays turn in the other direction.

We will now describe in detail the operation of the escapement escapement made according to the invention with the help of Figures 4 to 13 which illustrate different phases of this operation.

In figure 4 the trays 4 and 23 turn in the direction of the arrow a. The first finger 14 secured to the large plate 4 comes into contact with the second finger 11 fitted to the blocker 6. The pallet 7 of the stopper blocker 6 is fully engaged in the tooth 60 of the escapement wheel 2 which is locked.

In figure 5 the trays 4 and 23 continue their course in the direction of the arrow a. The second finger 11 driven by the first finger 14, begins to bypass a first side 20 of said first finger 14 which causes the blocker 6 to rotate in the direction of the arrow c and to release the pallet 7 of the tooth 60. On the figure 5 , palette 7 is at the very beginning of this release.

In figure 6 , the escape wheel is released and rotates in the direction of the arrow e. The pallet 7 is completely disengaged from the tooth 60 and the tooth 61 of the wheel 2 comes into contact with the pulse pallet 5. This is the beginning of the pulse given to the plates 4 and 23. Wheel 2 continues to rotate in the direction of arrow e.

In figure 7 , the pulse given by the tooth 61 to the pallet 5 continues to rotate the trays 4 and 23 in the direction of the arrow a. The second finger 11 driven by the first finger 14 continues to bypass the side 20 of said first finger 14 along which it slides.

In figure 8 the wheel 2 is still moving and continues to drive the pulse pallet 5. The second finger 11 has passed under the first finger 14 and comes into contact with the ramp 25 of the notch 22 formed in the second plate 23.

In figure 9 , the tooth 61 of the wheel 2 is leaving the pulse pallet 5. The second finger 11, driven by the small plate 23 has climbed the side 25 of the notch 22 rotating the blocker 6 in the direction of the arrow f and forced the pallet 7 to break into the space between the teeth 60 and 62.

In figure 10 tooth 62 has come into contact with the rest pallet 7.

In figure 11 it can be seen that the tip of the tooth 62, pushed by the kinetic energy of the wheel 2, is housed on a rest line 33 of which the pallet 7 is provided. In fact, in this first embodiment of FIG. invention, the face 30 (see also figures 1 and 2 ) against which abuts a tooth of the wheel 2 comprises a first rest plane 31 located at the front of the pallet 7 and a second rest plane 32 located at the rear, this second plane being inclined relative to the first for The point of the tooth 62 by pulling effect, well known to watchmakers, is housed on the line of rest 33 and stops there, the second rest plane 32 standing in front of it. preventing him from continuing his journey. It will be observed that this device allows to do without stop pin that is generally available to limit the frog of the blocker.

The figure 11 shows again that the second finger 11 has taken off the circular periphery 24 of the small plate 23, allowing the pendulum full freedom to travel its additional arc in the direction of the arrow a. Note that from this moment the exhaust is resistant to shocks that could affect the timepiece. Indeed, a shock would abut the second finger 11 against the periphery 24 of the small plate 23 without resulting in a release of the pallet 7, the return of the tooth 62 on the line of rest 33 operating immediately after the shock thanks to the draw already cited.

In figure 12 , the exhaust is shown at the end of completion of the additional inverse arc (second alternation of the balance). The trays 4 and 23 then rotate in the direction of the arrow b. The first actuating finger 14 comes into contact with its second side 21 with the second finger 11. The tooth 62 is still immobilized on the line 33 of the pallet 7.

In figure 13 the trays 4 and 23 continue their course in the direction of the arrow b. The second finger 11, driven by the first finger 14, has bypassed the second side 21 of said first finger 14, which causes the blocker 6 to rotate in the direction of the arrow f. At this time the tip of the tooth 62 climbs the second rest plane 32 of the pallet 7 forcing the wheel 2 to a slight backward movement against the driving force exerted on it. When the second finger 11 has left the first finger 14 tooth 62 will be lowered from the second rest plane 32 of the pallet 7 to stabilize again on the rest line 33. As already stated above, when the large and small trays 4 and 23 rotate in a second direction b, opposite to the first, the first finger 14 drives the second finger 11, which bypasses a second side 21, opposite the first of said first finger 14 to maintain the engagement of the pallet rest 7 in the escape wheel 2. We are then in the situation of the figure 4 and a new oscillation can begin again.

The Figures 14 to 16 illustrate the detent escapement according to a second embodiment. As can be seen, the single pallet of the previous embodiment has been replaced by first and second pallet rest 40 and 41 arranged one over the other, all the other components of the escapement remaining the same. The first and second pallets 40 and 41 respectively have first and second rest planes 42 and 43 inclined relative to each other to form a rest line 44 on which rests the tooth 62 of the wheel d Exhaust 2. The first rest plane 42 intercepts the tooth 62 of the wheel 2 when the first pallet 40 interposes between two teeth 60 and 62. As for the first embodiment, when the first finger 14 causes its second side 21 the second finger 11, the tooth 62 escalates the second plane 43 of the second pallet 41. The return of the tooth 62 on the line of rest 44 takes place when the second finger 11 leaves the first finger 14.

For the rest, the different phases of operation remain the same as those exposed and illustrated in Figures 4 to 13 . In particular, the tip of the tooth 62 by pulling effect, is housed on the line of rest 44 and stops there, the second rest plane 43 standing in front of it, preventing it from continuing on its way.

The Figures 17 to 19 illustrate the detent escapement according to a third embodiment. Here the single pallet of the first embodiment has been replaced by first and second pallets 50 and 51 cooperating respectively with first and second teeth 62 and 63 of the escape wheel 2. The first and second pallets rest respectively have first and second rest planes 52 and 53 inclined relative to each other. When the locking device is interposed between the teeth of the escape wheel, it is the first rest plane 52 of the first pallet 50 which intercepts the first tooth 62 of the wheel 2. This wheel is then blocked while done when the second rest plane 53 of the second pallet 51 comes into contact with the second tooth 63 of the wheel 2, the inclination of the rest plane 52 being chosen such that the climbing of the tooth 63 along said plan 52 is not possible. However, when the first finger 14 drives the second finger 11 by its second side 21, the second tooth 63 climbs the second rest plane 53 of the second blade 51 forcing the wheel 2 to move back slightly against the driving force that exercise on it. The second tooth 63 finally returns to the first point of contact of the second rest plane 53 with the second tooth 63, when the second finger 11 leaves the first finger 14.

For the rest, the different phases of operation remain the same as those explained about Figures4 to 13 .

For the described system to function properly, it is essential for the first and second actuating fingers 14 and 11 to be shaped so as to slide easily over each other since, as we have seen, the finger 14 drives the finger 11 by going through a complete turn around it. Several forms can be envisaged to achieve this goal. The figures illustrating this description show that the first actuating finger 14 has a parallelepipedal section and that the second actuating finger has a triangular section whose corners are rounded. The invention is of course not limited to these forms, for example it may very well be the first finger 14 which has a triangular section with rounded corners while the second finger 11 shows a parallelepiped section.

The exhaust described above seems entirely new in the sense that it operates without the help of any elastic member and that in this sense it is energy efficient consumed balance. In this sense also, it is ideal for equipping small timepieces, for example a wristwatch naturally provided with a small beam delivering little energy. In fact, can the escapement described be called detent escapement while a relaxation presupposes an elastic member to actuate it? The detent escapement still remains, in the present invention, the direct action of the escape wheel on the balance and the single pulse imparted to the balance for an oscillation of the latter.

Finally, we will notice that all the exhaust described is not more bulky than an anchor escapement mounted on a wristwatch, if not less, while the known detent escapements take up a lot of space, which is why we limit their use in large watches.

Claims (7)

1. Detent escapement for a timepiece including an escapement wheel (2) fitted with teeth (3), a balance, on the pin (16) of which are fixed a large roller (4) fitted with an impulse pallet-stone (5) and a first actuating finger (14) and a small roller (23) on the circular periphery (24) of which there is made a notch (22), and a blocking member in the form of a lever (6) hinged on a pin (8), said blocking member carrying a locking device (7; 40, 41; 50, 51) of the escapement wheel (2) and a second actuating finger (11), characterised in that said first and second fingers are shaped such that when the large and small rollers (4 and 23) rotate in a first direction (a), the first finger (14) drives the second finger (11) which moves around a first side (20) of said first finger (14) to release the device locking the escapement wheel (2), the second finger (11) being then driven by a rising flank (25) of the notch (22) of the small roller (23) to re-engage the locking device in the escapement wheel (2), and such that when the large and small rollers (4 and 23) rotate in a second direction (b) opposite to the first, the first finger (14) drives the second finger (11) which moves around a second side (21), opposite to the first side, of said first finger (14) to keep the locking device engaged in the escapement wheel (2).
2. Escapement according to claim 1, characterised in that the locking device is a locking pallet-stone (7) including a face (30) against which a tooth (62) of the escapement wheel (2) abuts, said face (30) including a first locking face (31) located in the front position of the pallet-stone (7) and a second locking face (32) located in the rear position, the second face being inclined with respect to the first to form a locking line (33) on which the tooth (62) of the wheel (2) rests, the first locking face (31) intercepting the tooth (62) of the wheel (2) when the pallet-stone (7) is inserted between two teeth (60 and 62), said tooth (62) climbing over said second locking face (32) when the first finger (14) drives by its second side (21) the second finger (11) said tooth (62) finally returning to the locking line (33) when the second finger (11) leaves the first finger (14).
3. Escapement according to claim 1, characterised in that locking device includes first (40) and second (41) locking pallet-stones arranged one above each other and respectively having first (42) and second (43) locking faces inclined in relation to each other to form a locking line (44) on which the tooth (62) of the wheel (2) rests, the first locking face (42) intercepting the tooth (62) of the wheel (2) when the first pallet-stone (40) is inserted between two teeth (60 and 62), said tooth (62) climbing over the second face (43) of the second pallet-stone (41) when the first finger (14) drives the second finger (11), via its second side (21), said tooth (62) finally returning to the locking line (44) when the second finger (11) leaves the first finger (14).
4. Escapement according to claim 1, characterised in that the locking device includes first (50) and second (51) locking faces respectively cooperating with first (62) and second (63) teeth of the escapement wheel (2), said first and second locking pallet-stones respectively having first (52) and second (53) locking faces inclined in relation to each other, the first locking face (52) of the first pallet-stone (50) intercepting the first tooth (62) of the wheel (2) when the locking device is inserted between the teeth of said wheel, the latter being locked when the second locking face (53) of the second pallet-stone (51) enters into contact with the second tooth (63), said second tooth (63) climbing over said second locking face (53) of said second pallet (51) when said first finger (14) drives said second finger (11) via its second sides (21) said second finger (63) finally returning to the point of contact of the second locking face (53) with the second tooth (63) when the second finger (11) leaves the first finger (14).
5. Escapement according to any of claims 2 to 4, characterised in that the blocking member (6) is arranged such that the second finger (11) is immobilised in proximity to, but without touching, the circular periphery (24) of the small roller (23), when the locking device locks the escapement wheel (2).
6. Escapement according to claim 1, characterised in that the first actuating finger (14) has a parallelepiped cross section and in that the second actuating finger (11) has a triangular cross section whose angles are rounded.
7. Escapement according to claim 1, characterised in that the first actuating finger (14) has a triangular cross section whose angles are rounded and in that the second actuating finger (11) has a parallelepiped cross section.

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