EP4198641B1 - Natural escapement for timepiece movement and timepiece movement comprising such an escapement - Google Patents

Description

Technical field of the invention

The present invention relates to a natural escapement for a clock movement, also known as a tangential impulse escapement. The present invention relates more particularly to a natural escapement protected against damage that may be caused by premature triggering of the escapement impulse in the absence of the balance. The present invention also relates to a clock movement comprising such an escapement.

Technological background

The principle of the natural escapement was invented by Abraham Louis Breguet at the beginning of the 19th century. The advantage of Breguet's natural escapement is that it is a free escapement, since the balance wheel is only disturbed by the operation of the escapement for a small fraction of its oscillation. Breguet's natural escapement also has the advantage of giving each alternation a direct and tangential impulse to the balance wheel. In other words, the energy is transferred directly from the escapement wheel to the balance wheel, without passing through an anchor. Furthermore, the energy is transmitted only tangentially, so that the friction generated by the operation of this escapement is limited. Unlike a detent escapement, a natural escapement does not have a lost stroke in its function of maintaining the oscillations of the balance wheel; it delivers a similar impulse at each alternation, in a symmetrical and more uniform manner, so that mechanical energy losses due to lost strokes are eliminated. All these qualities make the natural exhaust potentially one of the most efficient exhausts.

Breguet later discovered, however, that the natural escapement he had designed had certain drawbacks, the most important of which was that the last escape wheel was not under tension from the gear train when the first wheel was giving the impulse or when the latter was at rest. The various gear clearances and the manufacturing quality of the various components used in a Breguet natural escapement could thus cause the last escape wheel to be incorrectly positioned and, consequently, the escapement to malfunction, accompanied by parasitic noise. Furthermore, since the escape wheel was free, its position was unstable, so that the operating safety of such a natural escapement was poor.

Of course, many improvements have been made to the original Breguet natural escapement in an attempt to overcome the drawbacks mentioned above. However, despite the efforts of successive watch manufacturers, difficulties remain. Some watchmakers have proposed superimposing the two escape wheels, a solution which, of course, increases the thickness of the movement and makes it difficult to integrate such a movement into a watch case. Other watch manufacturers have proposed positioning the anchor between the two escape wheels, in the plane of the latter. Here too, such a solution is cumbersome, this time in the plane of the movement. Furthermore, whether the escape wheels are superimposed or the anchor is arranged between the two escape wheels, it has been found in practice that watchmakers have difficulty accessing the various components of the escapement, particularly when it comes to adjusting the penetration depth of the teeth of the first and second escape wheels with the exit and entry pallets of the anchor. Furthermore, when the watchmaker performs control or adjustment operations and removes the balance wheel for this purpose, it may happen that the impulse is triggered without either of the two impulse pallets carried by the balance plate being within the rotation perimeter of either escapement wheel to ensure the escapement function. In such cases, the escapement wheels are not held by the escapement function and can rotate without control. This then causes at best a loss of the timekeeping function with an unwanted advance, and at worst a sudden stop after acceleration of the gear train in one or other of its rest positions which may lead to damage to the components of the gear train and the escapement.

The document CH 712 631 A1 discloses a natural escapement having an anchor with additional lifts. These lifts have the function of retaining stops acting on the escapement wheel.

Summary of the invention

The present invention aims to overcome the above-mentioned and other problems by providing a natural escapement for a clockwork movement that is protected against the effects of triggering the escapement function when the balance wheel is not present.

For this purpose, the present invention relates to a natural escapement for a watch movement performing a succession of operating cycles each composed of a first and a second alternation of a balance wheel during which the balance wheel moves from a first extreme position to a second extreme position passing through a middle rest position, then from its second extreme position to its first extreme position passing through its middle rest position a second time, this balance wheel comprising a balance wheel on an axis of which a balance wheel plate is adjusted, this natural escapement comprising a first escape wheel provided with at least a first toothing, this first escape wheel, arranged to be driven by a wheel of the clockwork movement, in turn driving a second escape wheel provided with at least a second toothing, the first and second escapement wheels forming a kinematic chain arranged to cooperate with an anchor capable of pivoting about an anchor stem, the balance wheel causing the anchor to pivot at each of the first and second vibrations, this anchor being arranged to block respectively the first and second escapement wheels temporarily during the second and first vibrations of an operating cycle, the anchor further comprising a first, respectively a second safety lever, these first and second safety levers being arranged so that, in the absence of the balance, one or other of the second and first escapement wheels, by driving the second or first safety lever, causes the anchor to pivot to ensure the rest of the first or second escapement wheels by stopping this first or second escapement wheel on a part of the anchor which performs the function of a pallet for stopping this first or second escapement wheel in normal operation of the escapement, the first and second safety levers safety being arranged so as not to be in contact with the first and second escapement wheels during normal operation of the escapement during which it is the balance wheel which causes the pivoting of the anchor.

• au moins un premier levier, pivoté autour d'un axe de pivotement, étant raccordé au premier bras de l'ancre via au moins une articulation à pivotement, l'ancre comprenant un second levier qui prolonge son second bras, ces premier et second leviers étant agencés pour bloquer respectivement les première et seconde roues d'échappement de manière temporaire au cours des seconde et première alternances d'un cycle de fonctionnement, le débattement des premier et second leviers en pivotement étant limité ;
• les premier et second leviers sont pivotés autour d'axes de pivotement respectifs et sont raccordés respectivement aux premier et second bras de l'ancre via au moins une articulation à pivotement ;
• les articulations à pivotement sont formées chacune d'un ergot qui fait saillie dans une ouverture oblongue ;
• le débattement en pivotement de l'ancre est limité par des première et seconde butées de limitation ;
• les première et seconde butées de limitation sont des goupilles ;
• les première et seconde butées sont usinées dans un élément fixe du mouvement d'horlogerie ;
• les première et seconde butées de limitation sont des excentriques ;
• le premier levier est fait d'une pièce et présente une géométrie qui assure la fonction d'une première palette d'arrêt pour bloquer temporairement la première roue d'échappement au cours de la seconde alternance, et le second levier est fait d'une pièce et présente une géométrie qui assure la fonction d'une seconde palette d'arrêt pour bloquer temporairement la seconde roue d'échappement au cours de la première alternance ;
• la première roue d'échappement comprend une première denture d'entraînement par laquelle elle engrène avec une seconde denture d'entraînement de la seconde roue d'échappement, et les première et seconde roues d'échappement comprennent chacune une denture d'impulsion et de repos par lesquelles elles fournissent une impulsion motrice directe et tangentielle au plateau de balancier, les dentures d'entraînement et d'impulsion et de repos de chacune des première et seconde roues d'échappement s'étendant dans un plan unique ou dans deux plans parallèles ;
• l'ancre comprend une fourchette formée d'une première et d'une seconde corne, le plateau de balancier venant buter par sa cheville de balancier contre la seconde corne de la fourchette et provoquant le pivotement de cette ancre dans un premier sens lors de la première alternance, et contre la première corne lors de la seconde alternance, provoquant le pivotement de l'ancre dans un second sens opposé au premier ;
• la fourchette porte un dard qui coopère avec le plateau de balancier pour empêcher les déplacements accidentels de la fourchette pendant une période appelée arc supplémentaire ;
• les première et seconde roues d'échappement sont chacune monoblocs ;
• un mobile de réduction est disposé entre la roue de seconde et la première roue d'échappement.

According to special embodiments of the invention:

• at least one first lever, pivoted about a pivot axis, being connected to the first arm of the anchor via at least one pivot joint, the anchor comprising a second lever which extends its second arm, these first and second levers being arranged to respectively block the first and second escape wheels temporarily during the second and first alternations of an operating cycle, the movement of the first and second levers in pivoting being limited;
• the first and second levers are pivoted about respective pivot axes and are respectively connected to the first and second arms of the anchor via at least one pivot joint;
• the pivot joints are each formed by a lug which projects into an oblong opening;
• the pivoting travel of the anchor is limited by first and second limiting stops;
• the first and second limiting stops are pins;
• the first and second stops are machined in a fixed element of the clock movement;
• the first and second limiting stops are eccentrics;
• the first lever is made of one piece and has a geometry that provides the function of a first stop pallet for temporarily blocking the first escape wheel during the second alternation, and the second lever is made of one piece and has a geometry that provides the function of a second stop pallet for temporarily blocking the second escape wheel during the first alternation;
• the first escapement wheel comprises a first drive toothing by which it meshes with a second drive toothing of the second escapement wheel, and the first and second escapement wheels each comprise an impulse and rest toothing by which they provide a direct and tangential driving impulse to the balance wheel, the drive and impulse and rest toothing of each first and second escape wheels extending in a single plane or in two parallel planes;
• the anchor comprises a fork formed of a first and a second horn, the balance wheel bearing by its balance pin against the second horn of the fork and causing the pivoting of this anchor in a first direction during the first alternation, and against the first horn during the second alternation, causing the pivoting of the anchor in a second direction opposite to the first;
• the fork carries a stinger which cooperates with the balance wheel to prevent accidental movement of the fork during a period called the extra arc;
• the first and second escape wheels are each monobloc;
• a reduction wheel is arranged between the second wheel and the first escape wheel.

The invention also relates to a clockwork movement comprising a natural escapement of the type described above.

Thanks to these features, the present invention provides a natural escapement protected against damage that can be caused by premature triggering of the impulse. Indeed, by teaching to provide the first and second arms of the anchor with a first and second safety lever, the first escapement wheel is advantageously ensured to rest when, in the absence of the balance wheel, this rest is not ensured by the cooperation between this balance wheel and the anchor. Indeed, it is understood that in the absence of the balance wheel, the second escapement wheel is not retained by the escapement function and can therefore rotate without control, which can cause a loss of the timekeeping function with an undesired advance, or even a sudden stop after acceleration of the gear train of the watch movement which may lead to deterioration of the components of the gear train and the escapement. To achieve this objective, the first and second safety levers are arranged so that, in the absence of the balance, the second escapement wheel, by acting on the second safety lever, causes the pivoting of the second arm of the anchor, the anchor and the first arm of the anchor to ensure the resting of the first escapement wheel on the part of this anchor which, in normal times, i.e. when the balance wheel plate is present, performs the function of a stop pallet to temporarily block the first escapement wheel during an operating cycle of the natural escapement. Of course, the first and second safety levers are designed so as not to be in contact with the first and second escapement wheels during normal operation of the escapement during which it is the balance wheel plate which causes the pivoting of the anchor. Similarly, it will be understood that the symmetrical situation is also possible, namely that by pivoting the anchor controlled by the first escapement wheel, the rest of the second escapement wheel is ensured by pressing against the part of this anchor which, in normal times, ensures the function of a stop pallet to temporarily block the second escapement wheel during an operating cycle of the natural escapement.

Brief description of the figures

• la figure 1 est une vue d'ensemble de dessus d'un échappement naturel dans sa position de repos dans laquelle la seconde roue d'échappement est en appui sur le second levier ;
• la figure 2 est une vue de dessus de l'échappement naturel dans sa position dans laquelle la cheville de balancier arrive en contact avec la seconde corne de la fourchette, ce qui va provoquer le début du dégagement de la seconde roue d'échappement de sa prise avec le second levier ;
• la figure 3 est une vue de dessus de l'échappement naturel dans sa position dans laquelle le plateau de balancier entraîne l'ancre et les leviers, ce qui provoque le début de la première chute par dégagement de la seconde roue d'échappement de sa prise avec le second levier ;
• la figure 4 est une vue de dessus de l'échappement naturel dans sa position dans laquelle la première roue d'échappement vient prendre appui sur la première palette d'impulsion et commence à donner une impulsion au plateau de balancier, ce qui marque la fin de la première chute ;
• la figure 5 est une vue de dessus de l'échappement naturel dans sa position dans laquelle la première roue d'échappement imprime l'impulsion au plateau de balancier tandis que le second levier vient prendre appui contre la seconde butée de limitation ;
• la figure 6 est une vue de dessus de l'échappement naturel dans sa position dans laquelle la première roue d'échappement finit d'imprimer une impulsion au plateau de balancier, ce qui marque le début de la seconde chute, tandis que le second levier est en appui sur la seconde butée de limitation ;
• la figure 7 est une vue de dessus de l'échappement naturel dans sa position dans laquelle la première roue d'échappement prend appui sur le premier levier, ce qui marque la fin de la seconde chute, tandis que le plateau de balancier finit son alternance librement ;
• la figure 8 est une vue de dessus de l'échappement naturel de la figure 1 dans le cas où la roue de balancier a été retirée, l'ancre étant munie des levées de sécurité conformes à l'invention, l'échappement naturel étant dans la position dans laquelle la seconde roue d'échappement, par action sur la seconde levée de sécurité, va provoquer le pivotement de l'ancre pour assurer le repos de la première roue d'échappement par appui, via l'une des dents de sa denture d'impulsion et de repos, sur la partie de cette ancre qui, en temps normal, c'est-à-dire lorsque le plateau de balancier est présent, assure la fonction d'une première palette d'arrêt pour bloquer temporairement la première roue d'échappement au cours d'un cycle de fonctionnement de l'échappement naturel;
• la figure 9 est une vue analogue à celle de la figure 8 sur laquelle, en l'absence de la roue de balancier, la première roue d'échappement va, par action sur la première levée de sécurité, provoquer le pivotement de l'ancre de façon à permettre à la seconde roue d'échappement de venir en position de repos par appui d'une des dents de sa denture d'impulsion et de repos sur la partie de cette ancre qui, en temps normal, assure la fonction d'une seconde palette d'arrêt dont le rôle est de bloquer temporairement cette seconde roue d'échappement ;
• la figure 10 est une vue qui illustre la position de l'échappement naturel à la suite de la position dans laquelle cet échappement naturel se trouve à la figure 8 et sur laquelle, la roue de balancier étant absente, la seconde roue d'échappement a, par action sur la seconde levée de sécurité, provoqué le pivotement de l'ancre de façon à permettre à la première roue d'échappement de prendre sa position de repos par appui de l'une des dents de sa denture d'impulsion et de repos sur la partie de cette ancre qui, en temps normal, c'est-à-dire lorsque le plateau de balancier est présent, assure la fonction d'une première palette d'arrêt pour bloquer temporairement la première roue d'échappement au cours d'un cycle de fonctionnement de l'échappement naturel.

Other features and advantages of the present invention will emerge more clearly from the following detailed description of an embodiment of a natural escapement according to the invention, this example being given purely for illustrative and non-limiting purposes only in connection with the appended drawing in which:

• there figure 1 is a top view of a natural escapement in its rest position in which the second escape wheel rests on the second lever;
• there figure 2 is a top view of the natural escapement in its position in which the balance pin comes into contact with the second horn of the fork, which will cause the second escape wheel to begin to disengage from its engagement with the second lever;
• there figure 3 is a top view of the natural escapement in its position in which the balance wheel plate drives the anchor and the levers, which causes the first fall to begin by disengaging the second escape wheel from its engagement with the second lever;
• there figure 4 is a top view of the natural escapement in its position in which the first escape wheel comes to bear on the first impulse pallet and begins to give an impulse to the balance wheel, which marks the end of the first fall;
• there figure 5 is a top view of the natural escapement in its position in which the first escape wheel imparts the impulse to the balance wheel while the second lever comes to bear against the second limiting stop;
• there figure 6 is a top view of the natural escapement in its position in which the first escape wheel finishes imparting an impulse to the balance wheel, which marks the start of the second fall, while the second lever is resting on the second limiting stop;
• there figure 7 is a top view of the natural escapement in its position in which the first escape wheel rests on the first lever, which marks the end of the second fall, while the balance wheel plate finishes its alternation freely;
• there figure 8 is a top view of the natural exhaust of the figure 1 in the case where the balance wheel has been removed, the anchor being provided with safety levers in accordance with the invention, the natural escapement being in the position in which the second escapement wheel, by action on the second safety lever, will cause the pivoting of the anchor to ensure the resting of the first escapement wheel by pressing, via one of the teeth of its impulse and resting teeth, on the part of this anchor which, in normal times, that is to say when the balance wheel plate is present, ensures the function of a first stop pallet to temporarily block the first escapement wheel during an operating cycle of the natural escapement;
• there figure 9 is a view similar to that of the figure 8 on which, in the absence of the balance wheel, the first escapement wheel will, by action on the first safety lever, cause the pivoting of the anchor so as to allow the second escapement wheel to come into the rest position by pressing one of the teeth of its impulse and rest teeth on the part of this anchor which, in normal times, ensures the function of a second stop pallet whose role is to temporarily block this second escapement wheel;
• there figure 10 is a view which illustrates the position of the natural escapement following the position in which this natural escapement is located at the figure 8 and on which, the balance wheel being absent, the second escapement wheel has, by action on the second safety lever, caused the pivoting of the anchor so as to allow the first escapement wheel to take its rest position by pressing one of the teeth of its impulse and rest teeth on the part of this anchor which, in normal times, that is to say when the balance wheel plate is present, ensures the function of a first stop pallet to temporarily block the first escapement wheel during an operating cycle of the natural escapement.

Detailed description of the invention

The present invention proceeds from the general inventive idea which consists in providing the first and second arms of the anchor of a natural escapement, also known by its name tangential impulse escapement, with a first and a second safety lever in order to guarantee that, if the watchmaker, for any reason, needs to remove the balance wheel, an unexpected triggering of the rotation of the first and second escapement wheels is immediately stopped by bringing one of the first and second escapement wheels into its rest position. For this purpose, the safety levers are arranged so that, when the balance wheel is removed, the second escapement wheel, by action on the second safety lever, pivots the anchor and the first arm of this anchor to allow the first escapement wheel to come to a stop in its rest position resting against the part of this anchor which, in normal times, that is to say when the balance wheel is present, performs the function of a stop pallet to temporarily block the first mobile exhaust during a natural exhaust operating cycle.

Designated as a whole by the general numerical reference 1, the natural escapement is represented in its rest position at the figure 1 . This natural escapement 1 is arranged to be driven by a wheel of the clockwork movement, for example a second wheel 2 which, according to a preferred but non-limiting embodiment, meshes with a pinion 4 fixedly mounted on an axis 6 of a first escapement wheel comprising a first escape wheel 10. This first escape wheel 10 meshes via a first drive toothing 12 with a second drive toothing 14 of a second escapement wheel comprising a second escape wheel 16 which pivots about an axis 18.

The natural escapement 1 also comprises a balance wheel 20 which has a balance wheel 22 on an axis 24 from which a balance plate 26 is adjusted. This balance plate 26 carries a balance pin 28 as well as a first and a second impulse pallet 30 and 32 whose respective roles will be described below.

The natural escapement 1 also comprises an anchor 34 pivoted around an anchor stem 36. This anchor 34 comprises an anchor body 38 which carries a fork 40 formed of a first and a second horn 42a and 42b as well as a pin 44. This pin 44 cooperates with the balance wheel plate 26 in order to prevent accidental movements of the fork 40 outside the periods commonly called additional arcs, periods during which the balance wheel plate 26 is close to its median rest position called the lift angle.

As can be seen from the examination of the figure 1 , the anchor body 38 comprises a first and a second arm 46a and 46b which are preferably but not limited to arranged symmetrically on either side of the fork 40. According to an embodiment given to purely for illustrative purposes only, first and second levers 48a, 48b, pivoted about respective pivot axes 50 and 52, are connected to the first and second arms 46a, 46b of the anchor body 38 via a pivot joint 53. In this embodiment, the first lever 48a is made of one piece and has a geometry which provides the function of a first stop pallet for temporarily blocking the first escapement wheel 10 during an operating cycle of the natural escapement 1, and the second lever 48b has a geometry which provides the function of a second stop pallet for temporarily blocking the second escapement wheel 16 during the same operating cycle of the natural escapement 1.

According to the embodiment shown in the drawing, the first and second levers 48a, 48b each carry a lug 54, respectively 56, which projects into an oblong opening 58, respectively 60, formed in the first and second arms 46a, 46b of the anchor body 38. Of course, the lugs 54 and 56 could be carried by the first and second arms 46a, 46b, and the oblong openings 58, 60 could be formed in the first and second levers 48a, 48b. Thus, by engagement of the lugs 54, 56 in the oblong openings 58, 60, the first and second levers 48a, 48b are able to pivot relative to the first and second arms 46a, 46b of the anchor body 38.

In the embodiment of the natural escapement 1 illustrated in the drawing, it is assumed that the second wheel 2 which supplies the natural escapement 1 with the energy necessary for its operation rotates in a clockwise direction. The second wheel 2 therefore tends to rotate the pinion 4 and the first escapement wheel 10 on the axis 6 of which the pinion 4 is fixed in an anticlockwise direction, and the second escapement wheel 16 in a clockwise direction.

An operating cycle of the natural escapement 1 comprises two alternations during which the balance wheel plate 26 will go successively from a first extreme position to a second extreme position passing through a median rest position, then from its second extreme position to its first extreme position passing through its median rest position a second time. Thus, at the beginning of a cycle (see figure 1 ), the balance wheel 26 rotates towards its middle rest position by rotating clockwise, while the second escape wheel 16 rests on the second lever 48b.

At one point in his journey illustrated in the figure 2 , the balance wheel 26 arrives in a position in which it abuts by its balance pin 28 against the second horn 42b of the fork 40 and begins to cause the pivoting of the anchor 34 in the counterclockwise direction. The pivoting of the anchor 34 in the counterclockwise direction has the effect of beginning to release the second escapement wheel 16 from its engagement with the second lever 48b, which will allow the second wheel 2 to drive, via the first escapement wheel 10, the second escapement wheel 16 in the clockwise direction.

To the figure 3 , the natural escapement 1 is in a position in which the balance wheel 26 drives the anchor 34, which causes the start of the first fall by disengaging the second escape wheel 16 from its engagement with the second lever 48b. By “fall” is meant the periods of operation of the natural escapement 1 according to the invention during which the first and second escape wheels 10 and 16 are not in contact with either of the first and second levers 48a, 48b, or with either of the first and second impulse pallets 30, 32.

It will be understood that at the same time as the first escapement wheel 10 drives the second escapement wheel 16 to pivot clockwise, the first escapement wheel 10 also begins to give a driving impulse to the balance wheel 26 via a tooth 66 of an impulse and rest toothing 68 which drives the first impulse paddle 30 (see figure 4 ). This driving impulse is called direct and tangential because it is given directly by the first escapement wheel 10 to the balance wheel plate 26 and the path of the tooth 66 catches up with that of the first impulse pallet 30 of the balance wheel plate 26 tangentially, which allows for almost punctual and frictionless contact. It will also be noted that the arrival of the tooth 66 of the first escapement wheel 10 in contact with the first impulse pallet 30 of the balance wheel plate 26 marks the end of the first fall.

There figure 5 is a top view of the natural escapement 1 in its position in which the first escapement wheel 10 imparts the impulse to the balance wheel 26, while the second lever 48b pivots about its pivot axis 52 and comes to bear against the second limiting stop 64. This movement is controlled by the anchor 34 which, driven by the balance pin 28, pivots about its anchor stem 36 in an anticlockwise direction.

To the figure 6 , the first escape wheel 10 finishes giving an impulse to the balance wheel 26, which marks the start of the second fall. It can be seen that the tooth 66 of the first escape wheel 10 will no longer be in contact with the first impulse pallet 30 of the balance wheel 26. Furthermore, the second lever 48b is resting on the second limiting stop 64.

Finally, the figure 7 is a top view of the natural escapement 1 in its other rest position in which the first escape wheel 10 rests on the first lever 48a, which marks the end of the second fall, while the balance wheel 26 finishes its alternation freely by rotating clockwise. The following alternation during which the balance wheel 26 will rotate counterclockwise reproduces the same functions as those illustrated in Figures 2 to 7 symmetrically in reverse order.

There figure 8 is a top view of the natural exhaust 1 of the figure 1 in the case where the balance 20 has been removed, a situation schematically illustrated by representing the balance 20 in dotted lines. In accordance with the invention, the first and second levers 48a, 48b of the anchor 34 are respectively provided with a first safety lever 84 and a second safety lever 86. As can be seen in this figure 8 , the natural escapement 1 is in the position in which the second escapement wheel 16 will, by pivoting clockwise, act by one of the teeth of its impulse and rest toothing 70 on the second safety lever 86 carried by the second lever 48b and cause the pivoting of the anchor 34 to ensure the rest or blocking of the first escapement wheel 10 by pressing one of the teeth 66 of its impulse and rest toothing 68 on the part 88 of this anchor 34 which, in normal times, that is to say when the balance wheel 26 is present, ensures the function of a first stop pallet to temporarily block the first escapement wheel 10 during an operating cycle of the natural escapement 1.

The situation described above is illustrated in figure 10 on which, the balance 20 still being absent, the first escapement wheel 10 is at rest by the support of one of the teeth 66 of its impulse and rest toothing 68 on the part 88 of the anchor 34 which ensures the function of stop pallet. Indeed, under the effect of the pivoting of the anchor 34 caused by the rotation of the second escapement wheel 16, the part 88 of the anchor 34 which ensures the function of stop pallet is found in the perimeter of rotation of the first escapement wheel 10 and the first escapement wheel 10 comes by one of the teeth 66 of its impulse and rest toothing 68 to bear against this part 88 of the anchor 34.

Finally, the situation illustrated in the figure 9 is symmetrical to that represented in the figure 8 , namely that it is the first escapement wheel 10 which, by pivoting counterclockwise, will act on the first safety lever 84 carried by the first lever 48a and cause the pivoting of the anchor 34 to ensure the rest or blocking of the second escapement wheel 10 by pressing one of the teeth of its impulse and rest toothing 70 on the part 90 of this anchor 34 which, in normal times, that is to say when the balance wheel plate 26 is present, ensures the function of a second stop pallet to temporarily block the second escapement wheel 16 during an operating cycle of the natural escapement 1.

It goes without saying that the present invention is not limited to the embodiment which has just been described and that various modifications and simple variants can be envisaged without departing from the scope of the invention as defined by the appended claims. It will be understood in particular that, although the natural escapement 1 has been described in connection with an anchor 34 to the arms 46a, 46b of which are connected first and second levers 48a, 48b, it is entirely conceivable, in a simplified embodiment, to provide only a single lever pivotally connected to one of the arms of the anchor, the other lever being made in one piece with the second arm of the anchor 34. It will also be noted that the presence of the first and second levers 48a, 48b is not essential, the anchor 34 being able to comprise only the arms 46a, 46b, the first arm 46a having a geometry which ensures the function of a first stop pallet for temporarily blocking the first escapement wheel 10 during an operating cycle of the natural escapement 1, and the second arm 46b having a geometry which ensures the function of a second pallet. stop to temporarily block the second escape wheel 16 during the same operating cycle of the natural escapement 1. It will also be noted that a reduction wheel can be arranged between the second escape wheel 2 and the first escape wheel 10. The first escape wheel 10 comprises a first drive toothing 12 by which it meshes with a second drive toothing 14 of the second escape wheel 16. Likewise, the first and second escape wheels 10, 16 each comprise an impulse and rest toothing 68, 70 by which they provide a direct and tangential driving impulse to the balance wheel 26. The drive toothing 12, 14 and impulse and rest toothing 68, 70 of each of the first and second escape wheels 10, 16 extend in a single plane or in two parallel planes. Preferably, the first and second escape wheels 10, 16 are each in one piece.

Nomenclature

1.

Natural exhaust

2.

Second wheel

4.

Pinion

6.

Axis

10.

First escape wheel

12.

First drive tooth

14.

Second drive toothing

16.

Second escape wheel

18.

Axis

20.

Balance wheel

22.

Balance wheel

24.

Axis

26.

Balance plate

28.

Balance pin

30.

First impulse palette

32.

Second impulse palette

34.

Anchor

36.

Anchor rod

38.

Anchor body

40.

Fork

42a.

First horn

42b.

Second horn

44.

Dart

46a.

First arm

46b.

Second arm

48a.

First lever

48b.

Second lever

50.

Pivot axis

52.

Pivot axis

53.

Pivot joints

54.

Ergot

55.

Ergot

56.

Ergot

57.

Circular opening

58.

Oblong opening

60.

Oblong opening

62.

First limiting stop

64.

Second limiting stop

66.

Tooth

68.

Impulse and rest teeth

70.

Impulse and rest teeth

76.

Eccentrics

84.

First security lift

86.

Second security lift

88.

Part

90.

Part

Claims (18)

1. Natural escapement (1) for horological movement carrying out a succession of operating cycles each consisting of a first and of a second alternation of a balance (20) during which the balance (20) moves from a first extreme position to a second extreme position by passing through a middle rest position, then from its second extreme position to its first extreme position by passing again a second time through its middle rest position, this balance (20) comprising a balance wheel (22) on an arbor (24) of which is adjusted a balance plate (26), this natural escapement (1) comprising a first escape wheel set having at least one first toothing, this first escape wheel set, arranged to be driven by a wheel set of the train of the horological movement, driving in turn a second escape wheel set having at least one second toothing, the first and second escape wheel sets forming a kinematic chain arranged to cooperate with an anchor (34) capable of pivoting about an anchor-staff (36), the balance plate (26) causing the anchor (34) to pivot with each of the first and second alternations, this anchor (34) being arranged to lock respectively the first and the second escape wheel set temporarily during the second and first alternations of an operating cycle, the anchor (34) further comprising a first, respectively a second safety lever (84, 86), these first and second safety levers (84, 86) being arranged so that, in the absence of the balance (20), one or other of the second and first escape wheel sets, by driving the second or, respectively, the first safety lever (84, 86), causes the anchor (34) to pivot to ensure the locking of the first or of the second escape wheel set by abutment of this first or of this second escape wheel set on a portion (88, 90) of the anchor (34) that ensures the function of a stop pallet-stone of this first or of this second escape wheel set during normal operation of the escapement (1), the first and second safety levers (84, 86) being arranged so as not to be in contact with the first and second escape wheel sets during normal operation of the escapement (1) during which it is the balance plate (26) that causes the anchor (34) to pivot.
2. Escapement according to claim 1, characterised in that the anchor (34) comprises a first and a second arm (46a, 46b) arranged to lock respectively the first and the second escape wheel set temporarily during the second and first alternations of an operating cycle, the first safety lever (84) being arranged on the first arm (46a) of the anchor (34), whereas the second safety lever (86) is arranged on the second arm (86) of the anchor (34).
3. Natural escapement according to claim 2, characterised in that at least one first lever (48a), pivoted about a pivot pin (50) and whereon is arranged the first safety lever (84), is connected to the first arm (46a) of the anchor (34) via at least one pivoting articulation (53), the anchor (34) comprising a second lever (48b) that extends its second arm (46b) and whereon is arranged the second safety lever (86), these first and second levers (48a, 48b) being arranged to lock respectively a first and second escape wheel (10, 16) that are included in the first and second escape wheel sets temporarily during second and first alternations of an operating cycle, the pivoting displacement of the first and second levers (48a, 48b) being limited.
4. Escapement according to one of claims 2 and 3, characterised in that the balance plate (26) carries a second impulse pallet (32) whereby this balance plate (26) receives a direct and tangential driving impulse from the first escape wheel set during the first alternation, and a first impulse pallet-stone (30) whereby this balance plate (26) receives a direct and tangential driving impulse from the second escape wheel during the second alternation.
5. Natural escapement according to one of claims 2 to 4, characterised in that the balance plate (26) carries a balance pin (28) whereby this balance plate (26) causes the anchor (34) to pivot with each of the first and second alternations.
6. Natural escapement (1) according to claim 5, characterised in that the first and second levers (48a, 48b) are pivoted about the respective pivot pins (50, 52) and are connected respectively to the first and second arms (46a, 46b) of the anchor (34) via at least one pivoting articulation (53).
7. Natural escapement (1) according to claim 6, characterised in that the at least one of the pivoting articulations (53) are each formed of a catch (54, 56) that protrudes in an oblong opening (58, 60).
8. Natural escapement (1) according to one of claims 5 to 7, characterised in that the pivoting displacement of the anchor (34) is limited by first and second limit banking-pins (62, 64).
9. Natural escapement (1) according to claim 8, characterised in that the first and second limit banking-pins (62, 64) are pegs.
10. Natural escapement (1) according to claim 8, characterised in that the first and second limit banking-pins (62, 64) are machined in a fixed element of the horological movement.
11. Natural escapement (1) according to claim 8, characterised in that the first and second limit banking-pins (62, 64) are eccentrics.
12. Natural escapement (1) according to one of claims 5 to 11, characterised in that the first lever (48a) is made of one part and has a geometry that ensures the function of a first stop pallet-stone to temporarily lock the first escape wheel (10) during the second alternation, and the second lever (48b) is made of one part and has a geometry that ensures the function of a second stop pallet-stone to temporarily lock the second escape wheel (16) during the first alternation.
13. Natural escapement (1) according to one of claims 5 to 12, characterised in that the first escape wheel (10) comprises a first drive toothing (12) whereby it meshes with a second drive toothing (14) of the second escape wheel (16), and in that the first and second escape wheels (10, 16) each comprise an impulse and locking toothing (68, 70) whereby they provide a direct and tangential driving impulse to the balance plate (26), the drive (12, 14) and impulse and locking toothings (68, 70) of each of the first and second escape wheels (10, 16) extending in a single plane or in two parallel planes.
14. Natural escapement (1) according to claim 13, characterised in that the first and second escape wheels (10, 16) are each one-piece.
15. Natural escapement (1) according to one of claims 5 to 14, characterised in that the anchor (34) comprises a fork (40) formed of a first and of a second horn (42a, 42b), the balance plate (26) coming to abut by its balance pin (28) against the second horn (42b) of the fork (40) and causing this anchor (34) to pivot in a first direction during the first alternation, and against the first horn (42a) during the second alternation, causing the anchor (34) to pivot in a second direction opposite to the first.
16. Natural escapement (1) according to claim 15, characterised in that the fork (40) carries a dart (44) that cooperates with the balance plate (26) to prevent the accidental movements of the fork (40) during a period called supplementary arc.
17. Horological movement comprising a natural escapement (1) according to one of claims 5 to 16, characterised in that the wheel set of the train of the horological movement that drives the first escape wheel set is a second wheel (2) between which and the first escape wheel (10) is arranged an escape wheel set (10).
18. Horological movement comprising a natural escapement (1) according to one of claims 1 to 16.

Images