CH712862A2 - Shock absorber bearing for a timepiece. - Google Patents

Abstract

The present invention relates to a shock absorbing bearing for a tigeron of an axis of a mobile of a timepiece comprising a support block (1) intended to be driven, fixed or formed in the frame of said piece of timepiece, said support block (1) being provided with a housing adapted to receive a spring (12) with axial deformation and a kitten supporting a pierced stone traversed by the tigeron and a counter-pivot stone (5), the spring (12) ) being arranged in the housing between the kitten and at least one protruding portion of a peripheral rim of the support block, characterized in that the spring (12) is formed by a peripheral ring from which extend at least one extension (13) provided with a bearing head in contact with the counter-pivot stone, this bearing head having a circular arc shape whose interface with the extension is via its convex face.

Description

Description

TECHNICAL AREA

The present invention relates to a shock absorbing bearing for a timepiece, and more particularly the bearing of the balance shaft of a mechanical watch, to prevent the breakage of the small diameter pivot, located at its end, designated "tigeron", in the event of an axial or lateral impact, which can result simply from a sudden movement of the wearer's wrist.

BACKGROUND

The manufacturers of mechanical watches have long designed many devices for absorbing the energy resulting from a shock, including a side impact, the axis by abutting against a wall of the hole of the block of base it traverses, while allowing a momentary movement of the tigeron before it is brought back to its rest position under the action of a spring.

Figs. 1 to 3 illustrate a device, called "double inverted cone" which is currently used in timepieces on the market. A device of this type is for example described in patent FR 1 532 798.

A support block 1, whose base comprises a hole 2 for the passage of the balance shaft 3 terminated by a tigeron 3a, used to position a kitten 20 in which are immobilized a pierced stone 4 crossed by the tigeron 3a and a rock against pivot 5. The kitten 20 is held in a housing 6 of the support block 1 by a spring 10 which comprises in this example radial extensions 9 compressing the counter pivot stone 5. The housing 6 comprises two bearing surfaces 7, 7a in the form of inverted cones on which bear complementary lanes 8, 8a of the kitten 20, said litters to be executed with very high accuracy. In the event of an axial impact, the spring 10 acts alone to bring the balance shaft 3 back to its initial position. In case of lateral impact, that is to say when the end of the tigeron imbalances the kitten 20 out of its resting plane, the spring 10 cooperates with the complementary inclined planes 7, 7a; 8, 8a to refocus the kitten 20. The support block 1 comprises a peripheral rim 11 in which two diametrically opposed openings 11 are made.

The current spring is a substantially flat spring lyre 10. Such a spring comprises a base from which two arms extend. These curved arms are symmetrical and extend to give a lyre shape. Ideally, the arms are arranged to form two parts of the same circle whose center is the center of the lyre spring. Each arm comprises, at its free end, a hook for resting on projecting portions 11b of the flange extending at the openings.

The radial extensions 9 of the spring extend from the inside of the arms.

In a variant shown in FIG. 3, each spring arm is arranged to be bent to form an extension. The extension to an arcuate shape whose interface with the extension is through the concave face of said support head 9 '.

This configuration has the disadvantage of having only one fulcrum per arm in all circumstances. This point of contact is in the most rigid part of the extension. This causes an imperfect response of the spring. Indeed, during a weak shock, having a fulcrum in the most rigid part may result in absorption of energy by the tigeron while in case of significant shocks, no progressivity will be present.

SUMMARY OF THE INVENTION

The present invention therefore aims to overcome the disadvantages of the aforementioned prior art by providing a shock absorbing bearing comprising a pierced stone and a counter-pivot stone assembled in a kitten suspended by a lyre spring allowing a more progressive response to shocks.

For this purpose the invention relates to a shock absorbing bearing for a tigeron of an axis of a mobile of a timepiece comprising a support block intended to be driven, fixed or formed in the frame of said timepiece, said support block being provided with a housing adapted to receive an axial deformation spring and a kitten supporting a pierced stone traversed by the tigeron and a counter-pivot stone, the spring being arranged in the housing between the kitten and at least one projecting portion of a peripheral rim of the support block, characterized in that the spring is formed by a peripheral ring from which extend at least one extension provided with a contact head in contact with the counter-pivot stone, this bearing head having a shape of an arc whose interface with the extension is via its convex face.

In a first embodiment, said spring comprises two arc-shaped arms interconnected via a cross-member and having two free ends each comprising a bearing zone, said at least one extension extending from one of the two arms.

In a second embodiment, said support head has a curvature greater than that of the arms.

In a third embodiment, said spring is formed of a curved strip in order to achieve internal radial extensions disposed between annular portions, said internal radial extensions carrying the support head.

In a fourth embodiment, the spring comprises two diametrically opposed extensions.

In a fifth embodiment, the spring comprises three extensions.

In a sixth embodiment, the three extensions are regularly distributed.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the present invention will appear more clearly in the following description of an exemplary embodiment given by way of illustration and not limitation with reference to the accompanying drawings in which: FIGS. 1 to 2 show in perspective a shock absorbing bearing according to the prior art; fig. 3 shows a shock absorbing bearing spring according to the prior art; figs. 4 to 6 correspond to a shock absorbing bearing and its spring according to a first embodiment of the invention; fig. 7 is an alternative embodiment of the spring visible in FIG. 6; fig. 8 is another embodiment of the spring visible in FIG. 6; fig. 9 shows a second embodiment of a spring according to the invention

DETAILED DESCRIPTION OF THE INVENTION

Referring essentially to FIGS. 4 and 5, hereinafter describes a shock absorbing bearing 100 according to the invention intended to prevent the rupture or the decentering of the tigeron 202 of a balance shaft 200 of a timepiece. The elements of construction identical or similar to those of the prior art illustrated in preamble by FIGS. 1 and 2 will be designated by the same references.

The bearing comprises a support block 1 of circular shape defining a housing 6 whose center is pierced with a hole 2 to allow the passage of a balance shaft 200 terminated by a tigeron 202.

The support block 1 may be either an independent part driven or fixed by any other means in the frame of the watch movement, or be part of another part of the movement, such as a bridge or a plate.

As can be seen, the kitten 20 which supports the pierced stone 4 traversed by the tigeron 3a and the counter-pivot stone 5 is damped by a spring 12.

Indeed, the support block 1 comprises a peripheral rim 9 having two openings 10. These openings 10 are diametrically opposed and allowing the introduction of the spring 12. Indeed, the peripheral rim 9 comprises protruding portions 11 s' extending at the openings. More precisely, the two openings 10 making it possible to have a peripheral rim 9 in two identical parts. Each part comprises, at each end, a projecting portion 11 extending towards the center of the opening. These protruding portions 11 allow the spring 12 to take support. The spring 12 is a ring-shaped spring.

In a first embodiment shown in FIG. 6, the spring 12 is a lyre spring. Such a spring 12 consists of two arms 12a in the form of circular arc interconnected via a cross member 12b at one of their ends, all forming a peripheral ring shape 12 '. This spring 12 thus has two free ends each comprising a bearing zone 12c. Such a support zone 12c may be in the form of a curvature of each arm at its free end to widen the area.

This configuration of the spring allows it to be installed in the housing 6 of the support block. Indeed, once the kitten 20 in place, the spring 12 is installed. The spring 12 is installed so as to press the kitten into the housing while having the cross member 12b and the support zones 12c pressed against the projecting portions 11 of the peripheral rim.

To dampen the kitten during an impact, the spring 12 comprises at least one extension 13. This extension 13 extends from one of the arms 12a of the spring towards its center. This extension made of material with the spring 12 is used to exert a prestress on the stone against pivot and to bring the kitten into the housing during a shock.

The spring 12 is dimensioned so that only the extension is in contact with the counter-pivot stone. Similarly, the arcuate arms 12a are formed to have the same center and substantially form a circle of center C. This center C also becomes the center of the spring.

Cleverly according to the invention, the extension comprises, at its free end, a support head 14 made of material with the extension. This support head 14 has a shape of an arc whose interface with the extension 13 is made via the convex face of said arc. Each support head has a shape of an arc having a curvature greater than that of the arms forming the spring. The radius of the arc forming the support head is therefore greater than if this arc had a radius whose center was the center C of the spring. So we understand that the center C of the arc of

Claims (7)

circle of each arm is shifted with the center C of the spring as shown in fig. 7. The extension with its support head 14 thus has a shape similar to a tee. This design provides a tee-shaped extension 13 whose arms have better contact with the stone against pivot. The support head 14 of the extension 13 advantageously has a reverse curvature compared to that of the prior art described above. This makes it possible to force the contact with the "counter-pivot" stone in the ends since the support head has a shape tending to conform to the shape of the counter-pivot stone. An advantage of this configuration is to have several points of contact. Indeed, the shape of the support head 14 allows it to be, at rest, in contact with the stone against pivot 5 in two places E1 and E2. This increase in the number of contact points makes it possible to have a better stability of the support on the counter-pivot stone 5. [0030] During an impact, the kitten 20 is displaced by the axis and its tigeron. This displacement of the kitten 20 is damped by the spring 12. This spring 12 under the effect of the constraint exerted by the kitten 20, is deformed. In the case of the spring 12 according to the invention, the deformation following a shock has the effect of shifting the contact points E1, E2. These contact points E1, E2 thus tend to approach the center of the support head 14. This shift of the contact points E1, E2 is due to the specific shape of the support head. However, the central zone of the support head 14 is the most rigid part so that the deformation of this portion 14 is less easy. Therefore, the greater the shock and the greater the contact between the extension 13 of the spring 12 and the counter pivot stone 5 is on the most rigid zone of said extension. This allows to obtain a better damping during big shocks. This spring configuration 12 also provides a better view of the lubricant. In a kitten 20 as described, the lubricant is arranged between the pierced stone and the counter-pivot stone. With the configuration of the extension 13 and in particular the support head, the view of the center of the counter-pivot stone is released and defined. This is possible by the shape of the head or heads that tend to delimit an area. With a shape of an arc whose interface with the extension is done by the concave face, the extensions of the spring must be longer and the heads of supports offer a visual delimiting no zone and blocking the view on the lubricant. In a variant shown in FIG. 7, it will be possible to have a spring 12 provided with two extensions 13, these extensions being arranged ideally diametrically opposite. In another variant visible in FIG. 8, it will be possible to have a spring 12 provided with three extensions 13, these extensions being arranged to be angularly distributed. The spring 12 thus comprises 3 arms 12a. This distribution will be ideally with an angle of 60 degrees. In this variant, each extension thus has its center C '. In a second embodiment shown in FIG. 9, the spring 12 is a spring ring 120. Such a spring ring 301 comprises internal radial extensions 121 disposed between annular portions 122. These internal radial extensions 121 are constituted by the band forming the ring 120 which is bent towards the inside the ring all forming a peripheral ring shape 12 '. These internal radial extensions 121 are, preferably, regularly distributed over the round of the flat ring 120 so that the latter can act homogeneously. These internal radial extensions 121 each comprise the support head 14 according to the invention. It is then understood that the spring ring 120 can be oriented in any way with respect to the support block 1. This support block 1 also comprises a peripheral rim provided with a peripheral protruding portion extending towards the inside of the block support. The peripheral protruding portion may comprise a notch allowing the establishment of the spring ring 120, said peripheral protruding portion serving to retain the spring ring in place. Preferably, the spring ring may comprise three internal radial extensions. In this case, the peripheral protruding portion may comprise three notches allowing the establishment of the spring ring via a bayonet insertion, said extension serving to retain the spring ring in place. It will be understood that various modifications and / or improvements and / or combinations obvious to those skilled in the art can be made to the various embodiments of the invention described above without departing from the scope of the invention defined by the appended claims. claims 1. Shock absorbing bearing for a stem (3a) of an axis (3) of a mobile of a timepiece comprising a support block (1) intended to be driven, fixed or formed in the frame of said timepiece, said support block (1) being provided with a housing (6) provided for receiving a spring (12) with axial deformation and a kitten (20) supporting a pierced stone (4) traversed by the tigeron (3a ) and a counter-pivoting stone (5), the spring (12) being arranged in the housing (6) between the kitten and at least one projecting portion of a peripheral rim of the support block, characterized in that the spring ( 12) is formed by a peripheral ring (12 ") from which extend at least one extension (13, 121) provided with a bearing head (14) in contact with the counter-pivot stone, said head support having a shape of an arc whose interface with the extension is via its convex face. 2. shock absorbing bearing according to claim 1, characterized in that said spring comprises two arms (12a) in the form of circular arc interconnected via a cross member (12b) and having two free ends each comprising a zone d ' support (12c), said at least one extension extending from one of the two arms (12a). 3. shock absorbing bearing according to claim 2, characterized in that said bearing head (14) has a curvature greater than that of the arms (12a). A shock absorbing bearing according to claim 1, characterized in that said spring is formed of a curved strip to provide internal radial extensions (121) disposed between annular portions (122), said internal radial extensions (121). bearing the support head. 5. Shock absorber bearing according to one of the preceding claims, characterized in that the spring comprises two diametrically opposed extensions. 6. shock absorbing bearing according to one of the preceding claims, characterized in that the spring comprises three extensions. 7. shock absorbing bearing according to claim 6, characterized in that the three extensions are regularly distributed.