EP2977829B1 - Assembly with timepiece braking mobile - Google Patents

Description

Field of the invention

The invention relates to a mobile watchmaking assembly, comprising a shaft having a first surface cooperating in pivotal guidance with a second surface of a wheel pivotally mounted on said shaft, wherein said first surface or respectively said second surface comprises at least one braking surface that comprises at least one shoe subjected to the action of at least one first elastic return means, integral with said shaft or said wheel, and arranged to exert a radial force with respect to said axis of pivoting on said second surface or said first surface respectively.

The invention also relates to a clockwork mechanism comprising at least one such mobile braking assembly.

The invention also relates to a timepiece comprising at least one such mobile braking assembly.

The invention relates to the field of watch mechanisms, and more particularly the wheels.

Background of the invention

It is common, in watchmaking, to have to use non-tensioned workings, particularly when using boards or additional modules, for example for the display of a small second.

It is then known to brake at least one wheel, for example by the support of a leaf spring pressing on the axis or on the wheel of one of the wheels of the wheel. Such braking certainly avoids the visual perception of the gear sets at the level of the user, but generates a significant friction and wear. Indeed, the braking force is not constant from one movement to another, which often requires to oversize the braking force. Document D1, for example, discloses a wheel, which carries braking arms which act on the shaft of the wheel in order to brake the latter. An alternative is a braking magnetic nature, which is not always desired in a watch movement.

The use of flexible teeth is an elegant solution, the braking then being done at the level of the teeth, but expensive.

Summary of the invention

The invention proposes to deal with the problem of angular gaps in a wheel, in particular an unstressed wheel, by the use of friction.

To this end, the invention relates to a mobile watchmaking assembly, comprising a shaft having a first surface cooperating in pivotal guidance with a second surface of a wheel pivotally mounted on said shaft, wherein said first surface or respectively said second surface comprises at least one braking surface that comprises at least one first arm subjected to the action of at least one first elastic return means, integral with said shaft or said wheel respectively, and arranged to exert a radial force by relative to said pivot axis on said second surface or respectively said first surface, characterized in that said movable braking assembly comprises intrinsic means of adjustment by discrete values of the friction exerted by said braking surface on said second surface or respectively said first surface.

According to a characteristic of the invention, said first surface or said second surface respectively comprises, distinct from each other, on the one hand at least one guide surface according to a predetermined clearance, around a pivot axis, said second surface or respectively said first surface, and secondly at least one said braking surface.

The invention also relates to a clockwork mechanism comprising at least one such mobile braking assembly.

The invention also relates to a timepiece comprising at least one such mobile braking assembly.

Brief description of the drawings

• la figure 1 représente, de façon schématisée et en coupe dans un plan perpendiculaire à l'axe de pivotement, un ensemble à mobile de freinage selon une première exécution de l'invention, où il est composé d'un arbre sur lequel pivote une roue qui coopère avec lui, d'une part par une surface de guidage, et d'autre part par une surface de freinage exerçant sur l'arbre un effort radial centripète, sous l'action de moyens de rappel élastique exerçant une friction réglable sous l'action de moyens d'ajustement par valeurs discrètes;
• la figure 2 représente, de façon similaire à la figure 1, une variante de cette première exécution ;
• la figure 3 représente, de façon similaire à la figure 1, une deuxième exécution ;
• la figure 4 représente, de façon similaire à la figure 1, une troisième exécution, avec une pluralité de bras courbes sensiblement concentriques à l'arbre ;
• la figure 5 représente, de façon similaire à la figure 1 mais non en coupe, une quatrième exécution, avec deux bras tendus sur la serge de la roue et pinçant l'arbre, chacun de ces bras étant soumis à un effort de poussée radial centripète exercé par des deuxièmes moyens de rappel élastique incorporés à la roue ;
• la figure 6 de façon similaire à la figure 5, une cinquième exécution, qui comporte encore, au niveau de la roue, des surfaces de guidage fixes de l'arbre, indépendantes des surfaces de freinage ;
• la figure 7 représente, sous forme d'un schéma-blocs, une pièce d'horlogerie comportant un mécanisme lequel inclut un tel ensemble à mobile de freinage.

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

• the figure 1 represents, schematically and in section in a plane perpendicular to the axis of pivoting, a movable braking assembly according to a first embodiment of the invention, wherein it is composed of a shaft on which pivots a wheel which cooperates with him, on the one hand by a guide surface, and on the other hand part by a braking surface exerting on the shaft a centripetal radial force, under the action of elastic return means exerting an adjustable friction under the action of adjustment means by discrete values;
• the figure 2 represents, similarly to the figure 1 a variant of this first execution;
• the figure 3 represents, similarly to the figure 1 a second execution;
• the figure 4 represents, similarly to the figure 1 a third embodiment, with a plurality of curved arms substantially concentric with the shaft;
• the figure 5 represents, similarly to the figure 1 but not in section, a fourth embodiment, with two arms extended on the wheel serge and pinching the shaft, each of these arms being subjected to a centripetal radial thrust force exerted by second elastic return means incorporated in the wheel ;
• the figure 6 similarly to the figure 5 a fifth embodiment, which further comprises, at the wheel, fixed guide surfaces of the shaft, independent of the braking surfaces;
• the figure 7 represents, in the form of a block diagram, a timepiece comprising a mechanism which includes such a movable braking assembly.

Detailed Description of the Preferred Embodiments

The invention relates more particularly to the field of clockwork.

The invention relates to a mobile brake assembly 1 clock, comprising a shaft 2 and a wheel 5 pivotally mounted on the shaft 2.

The shaft 2 comprises a first surface 3, which cooperates in pivotal guiding with a second surface 4 of the wheel 5.

The first surface 3 or the second surface 4 comprises at least one braking surface 11 carried by at least one first braking arm 30 subjected to the action of at least one first elastic return means 13. This first return means elastic 13 is preferably integral with the shaft 2 or the wheel 5, and is arranged to exert a radial force by relative to the pivot axis D on the second surface 4 or respectively the first surface 3.

The first elastic return means 13 is advantageously a flexible blade, more flexible than the shoe 12, which is cantilevered at a distal end of this blade, in the manner of a hammer head on its handle, the end of the flexible blade opposite the shoe being embedded in the corresponding structure, here the structure of the wheel 5 in the cases illustrated by the Figures 1 to 4 .

According to the invention, this assembly 1 comprises intrinsic adjustment means 14 by discrete values of the friction exerted by the braking surface 11 on the second surface 4, or respectively the first surface 3.

It is thus understood that the friction can theoretically be ensured as well by a component of the wheel 5 pressing on a continuous surface of the shaft, as the opposite. The invention is more particularly illustrated in this configuration of a component of the wheel 5 exerting friction on a continuous surface of the shaft, because of the ease of embodiment, and also the interest that the use of a tree of small diameter and very simple geometry, which can then advantageously be made of a very hard material such as ruby, ceramic, carbide, high speed steel, or the like.

According to a particular characteristic of the invention, as visible on the Figures 1 to 4 the first surface 3 or respectively the second surface 4 comprises, distinct from one another, on the one hand at least one guide surface 10 according to a predetermined clearance J, about a pivot axis D, of the second surface 4 or respectively the first surface 3, and secondly at least one such braking surface 11, that comprises at least one shoe 12, at the distal end of a first arm 30, subjected to the action of at least less than a first elastic return means 13. This first elastic return means 13 is preferably integral with the shaft 2 or the wheel 5, and is arranged to exert a radial force with respect to the pivot axis D on the second surface 4 or the first surface 3.

In the illustrated embodiments, which are in no way limitative, these intrinsic adjustment means 14 comprise at least one bearing surface 18, which is arranged to cooperate in thrust support with a complementary bearing surface 17 that the shoe 12 has on the side opposite to the braking surface 11.

The Figures 1 to 3 show in particular intrinsic adjustment means 14 which comprise at least one second flexible arm 19 carrying such a bearing surface 18.

This second arm 19 is, or as on the figure 3 radially limited relative to the pivot axis D opposite it in abutment against an adjusting device 20 arranged to occupy one of a plurality of discrete positions relative to the shaft 2 (or respectively to wheel 5), or as on the Figures 1 and 2 recalled to the complementary bearing surface 17 of the shoe 12 by a second elastic return means 16.

The Figures 1 and 2 illustrate a movable braking assembly 1 where the second arm 19 is biased towards the complementary bearing surface 17 of the shoe 12 by the second elastic return means 16. This second arm 19 comprises at least one finger 15 (or respectively a notch), subjected to the return action of the second resilient return means 16 and arranged to cooperate with only one of a plurality of notches 23 that includes the shaft 2 or respectively the wheel 5, in this case the wheel 5 in the case of the figures, each said notch 23 corresponding to a different friction setting value. The Figures 1 and 2 show a series of notches 23 similar to a comb or a toothing, arranged to maintain the position of the finger 5 after its operation.

The second elastic return means 16 is advantageously a flexible blade, more flexible than the finger 15, which is cantilevered at a distal end of this blade, in the manner of a hammer head on its handle, the end of the flexible blade opposite the finger being embedded in the corresponding structure, here the structure of the wheel 5 in the cases illustrated by the figures.

In an advantageous embodiment, the shoe 12 is subjected to both the action of at least one first elastic return means 13 and to the action of the second elastic return means 16.

The second elastic return means 16 may constitute a simple limit stop for the shoe 12, whose complementary bearing surface 17 then comes into simple support on the bearing surface 18 of the second arm 19, as visible on the figure 1 in this case, the second elastic return means 18 serves essentially to adjust the friction, allowing movement of the finger 15 and placing it in cooperation with a notch 23 selected for a particular value of friction.

The figure 2 shows that the second elastic return means 16 can also be used to make its own contribution to the friction, by the exercise of a radial centripetal force F on the shoe 12. Preferably, the torque exerted on the shoe 12 by the first elastic return means 13 is greater than that exerted by the second elastic return means 16.

Advantageously, the second elastic return means 16 is integral with the shaft 2 or respectively the wheel 5, here the wheel 5 in the case of the figures.

In the variant of the figure 3 , the second arm 19 is limited radially with respect to the pivot axis D, opposite it, in abutment abutment on an adjusting device 20, which comprises an eccentric adjustment by discrete positions, by example by the use of an eccentric 21 pivoting on the wheel 5, on which it can be stopped in different angular positions, by a notch or the like.

The forms of the elastic return means, hooves, arms, and notches, can be very diverse. The figure 4 thus illustrates a third embodiment, with a plurality of curved arms and blades substantially concentric with the shaft 2.

The figure 5 illustrates a fourth embodiment, with two arms 30, which are not cantilevered like those of Figures 1 to 4 , but stretched on the serge of the wheel 5 between attachment points 51, 52, 53, 54, and pinching together the shaft 2, each of these arms 30 being subjected to a centripetal radial thrust force exerted by second elastic return means 16 incorporated in the wheel 5. The shaft 2 is then guided by two braking surfaces 11, and there is no area reserved for guiding, as the guide surfaces 4 of the other embodiments. The arrangement of the intrinsic adjustment means 14 is similar to that of the other embodiments presented above. Naturally this variant can be declined with a number of upper arms.

It is still conceivable to combine this fourth embodiment with fixed guide surfaces 4, independent of the braking surfaces 11, and carried by fixed arms 31, as visible on a fifth embodiment. figure 6 .

Naturally, the assembly 1 according to the invention may comprise a plurality of braking surfaces 11, in particular distributed in a balanced manner about the pivot axis D.

In an advantageous embodiment because non-magnetic, the wheel 5 is made of monocrystalline or polycrystalline silicon, or a similar material implemented by a photolithographic process, or "MEMS" or "LIGA", or the like.

In an advantageous embodiment, the shaft 2 is made of ruby.

Preferably, the movable braking assembly 1 according to the invention consists solely of two components which are the shaft 2 and the wheel 5. And this shaft 2 and this wheel 5 are each a one-piece component comprising all the surfaces of necessary support, as well as the means of recall and maintenance required.

Advantageously, the shaft 2 is fixedly mounted on a plate or a bridge that comprises a mechanism 100 or a clockwork movement in which is integrated the movable braking assembly 1 considered.

The invention also relates to a clockwork mechanism 100, in particular a movement, comprising at least one such movable braking assembly 1.

The invention also relates to a timepiece 200 comprising at least one such movable braking assembly 1.

In short, the setting of the brake arming, thus achieved, makes it possible to modify the frictional force (or torque) exerted on the shaft, in a reproducible manner, which facilitates and speeds up the adjustments.

The invention makes it possible to reduce the number of components compared to a traditional mechanism, in order to reduce the gear sets (still visible on the display at the level of the needles), which goes in the direction of improved reliability, and a reduction in costs, especially since a manufacturing by cutting is possible.

The invention reduces wear compared to traditional spring brakes.

Claims (15)

1. Timepiece brake wheel assembly (1), including an arbor (2) comprising a first surface (3) cooperating, to guide pivoting, with a second surface (4) of a wheel (5) pivotally mounted on said arbor (2), wherein said first surface (3) or respectively said second surface (4) includes at least one braking surface (11) carried by at least a first braking arm (30) subjected to the action of at least a first elastic return means (13), in one-piece with said arbor (2) or respectively said wheel (5), and arranged to exert a radial force with respect to said pivot axis (D) on said second surface (4) or respectively said first surface (3), characterized in that said brake wheel assembly includes built-in means (14) for discrete value adjustment of the friction exerted by said braking surface (11) on said second surface (4) or respectively said first surface (3).
2. Timepiece brake wheel assembly (1) according to claim 1, characterized in that said first surface (3) or respectively said second surface (4) includes, distinct from each other, on the one hand at least one guide surface (10) with a predetermined play, about a pivot axis (D) of said second surface (4) or respectively said first surface (3), and on the other hand at least one said braking surface (11).
3. Brake wheel assembly (1) according to claim 1 or 2, characterized in that said built-in adjustment means (14) include a bearing surface (18) arranged to cooperate in push abutment with a complementary bearing surface (17) comprised in said brake shoe (12) on the side opposite said braking surface (11).
4. Brake wheel assembly (1) according to claim 3, characterized in that said built-in adjustment means (14) include at least a second flexible arm (19) carrying said bearing surface (18), said second arm (19) being, either radially limited with respect to said pivot axis (D), opposite thereto in abutment on an adjustment device arranged to occupy one of a plurality of discrete positions with respect to said arbor (2) or respectively said wheel (5), or returned towards said complementary bearing surface (17) of said brake shoe (12) by a second elastic return means (16).
5. Brake wheel assembly (1) according to claim 4, characterized in that said second arm (19) is returned towards said complementary bearing surface (17) of said brake shoe (12) by said second elastic return means (16), and includes at least one finger-piece (15), or respectively one notch, subjected to the return action of said second elastic return means (16) and arranged to cooperate with only one notch at a time of a plurality of notches (23) comprised in said arbor (2) or respectively said wheel (5), each said notch (23) corresponding to a different friction adjustment value.
6. Brake wheel assembly (1) according to claim 5, characterized in that said brake shoe (12) is subjected both to the action of at least a first elastic return means (13) and to the action of said second elastic return means (16).
7. Brake wheel assembly (1) according to any of claims 4 to 6, characterized in that said second elastic return means (16) is in one-piece with said arbor (2) or respectively said wheel (5).
8. Brake wheel assembly (1) according to any of claims 4 to 7, characterized in that the torque exerted on said brake shoe (12) by said first elastic return means (13) is greater than that exerted by said second elastic return means (16).
9. Brake wheel assembly (1) according to claim 4, characterized in that said second arm (19) is radially limited with respect to said pivot axis (D) opposite thereto in abutment on said adjustment device (20) which includes an eccentric adjustment in discrete positions.
10. Brake wheel assembly (1) according to any of the preceding claims, characterized in that said wheel (5) is made of single crystal or polycrystalline silicon.
11. Brake wheel assembly (1) according to any of the preceding claims, characterized in that said arbor (2) is made of ruby.
12. Brake wheel assembly (1) according to any of the preceding claims, characterized in that the assembly comprises only two components which are said arbor (2) and said wheel (5).
13. Brake wheel assembly (1) according to any of the preceding claims, characterized in that said arbor (2) is fixedly mounted on a main plate or a bridge comprised in a timepiece mechanism or movement (100) in which said brake wheel assembly (1) is integrated.
14. Timepiece mechanism (100) including at least one brake wheel assembly (1) according to any of the preceding claims.
15. Timepiece (200) including at least one brake wheel assembly (1) according to any of claims 1 to 13.

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