HK1243779B - Anti-shock system with angular locking - Google Patents

Description

Anti-vibration system with angle locking

Technical Field

The present invention relates to an anti-seismic system for an arbour of a timepiece wheel set. The arbour comprises a pivot-shank having a support provided with a housing for receiving a pivot system, into which the pivot-shank is inserted. The anti-seismic system also comprises elastic means arranged to exert at least an axial force on the pivot system.

The technical field of the present invention is the technical field of precision machinery.

Background Art

The present invention relates to bearings for timepieces, and more particularly to bearings of the shock-resistant type. Designers of mechanical watches have long devised numerous devices that allow the arbour to absorb the energy generated by shocks, particularly lateral shocks, by abutting against the wall of the hole through which it passes in the base, while at the same time allowing a temporary movement of the pivoting stem before returning to its rest position under the action of a spring.

Figures 1 and 2 show a device, known as a double inverted cone device, which is currently used in timepieces found on the market.

The base of the support 1 comprises a hole 2 for the passage of the balance staff 3 terminating in a pivoting stem 3a, and the support 1 allows the positioning of a mounting seat 20 in which the jewel bearing hole component 4 and the endstone 5, through which the pivoting stem 3a passes, are fixed. The mounting seat 20 is retained in the housing 6 of the support 1 by a spring element 10, which in this example comprises a radial extension 9 of the endstone 5. The support 1 is a rotationally symmetrical component comprising a circular edge portion 11. The edge portion 11 is interrupted by notches 12 at two diametrically opposite locations, thereby producing two semicircular edge portions 11a, 11b. The notches 12 are partially arranged in the two semicircular edge portions 11a, 11b, thereby forming two return portions. The mounting seat 20 is retained in the housing 6 of the support 1 by elastic means, such as a spring element 10, which in this example comprises a radial extension 9 of the endstone 5. Spring element 10 is of axial type and lyre-shaped, resting on the return portion of semicircular rims 11a, 11b. Cavity 6 includes two shoulders 7, 7a in the form of an inverted cone, which rest against complementary shoulders 8, 8a of mounting seat 20. These shoulders must be manufactured with great precision. In the event of axial vibration, the jewel bearing hole component 4, endstone 5, and balance staff move, and spring element 10 alone acts to return balance staff 3 to its initial position. Spring element 10 is dimensioned to have a limited displacement, so that if the limit is exceeded, balance staff 3 comes into contact with stop 14, allowing it to absorb vibrations that its pivoting stem 3a cannot do without breaking. In the event of lateral vibration, i.e., when the end of the pivoting stem interferes with mounting seat 20, causing it to move out of its resting plane, spring element 10 cooperates with complementary inclined surfaces 7, 7a; 8, 8a to realign mounting seat 20. These bearings are sold, for example, under the trademark . These spring elements may be made of phynox or brass and manufactured by conventional cutting methods.

One drawback of these shock absorber systems is that they are not easy to install. Indeed, several components, such as the support element 1 and the spring element 10, must be oriented and manipulated in a certain manner during the installation operation to achieve assembly. Therefore, assembly of the shock absorber system begins with obtaining the support element and then obtaining the mounting seat with its jewel bearing. The mounting seat is placed in a receptacle in the support element. Next, the harp-shaped axial spring element is obtained. This spring element is manipulated so that it rests beneath the return portion of the semicircular edge portions 11a, 11b of the support element.

Summary of the Invention

An object of the present invention is to overcome the drawbacks of the prior art by providing a shock absorber system whose assembly process is simple, reliable and can be automated.

To this end, the present invention relates to a shock absorber device for a central shaft of a watch element, the shock absorber device comprising a support member, which includes a base cup body with a circumferential edge portion on the top, the circumferential edge portion being bounded by an upper surface opposite to the base cup body and including an outer wall, the base cup body and the circumferential edge portion together defining a receiving portion, the shock absorber device also comprising at least one pivot module extending along an axis, the at least one pivot module being arranged in the receiving portion and capable of cooperating with the central shaft, the shock absorber device comprising a fastening device comprising a circumferential shoulder extending from the circumferential edge portion toward the axial center of the base cup body, an elastic device being arranged between the pivot module and the shoulder to apply stress to the pivot module.

It is characterized in that the elastic device includes a spring ring, which is provided with at least one radial extension extending toward the center of the spring ring and at least two catches extending in opposite directions, and the shoulder includes at least one notch to allow bayonet assembly of the spring ring; and, on both sides of the at least one notch, the shoulder includes a beak oriented toward the base cup body to allow the elastic device to be locked in rotation.

In a first advantageous embodiment, the shoulder comprises three notches and the spring ring comprises three snap-fit portions.

In a second advantageous embodiment, the elastic means comprise a spring ring having at least two arms extending towards the axial centre of the spring ring in order to press the pivoting module into the housing of the support.

In a third advantageous embodiment, said at least two arms are diametrically opposed.

In a further advantageous embodiment, the spring coil comprises three angularly distributed elastic arms.

In another advantageous embodiment, the elastic means comprise a spring coil having an inner radial extension arranged between annular portions, the inner radial extension consisting of the band forming the spring coil being bent towards the interior of the spring coil.

In another advantageous embodiment, said inner radial extensions are regularly distributed.

In another advantageous embodiment, the spring ring comprises three inner radial extensions.

BRIEF DESCRIPTION OF THE DRAWINGS

The objects, advantages and features of the anti-vibration system or shock absorber device according to the invention will become more apparent from the following detailed description of at least one embodiment of the invention, given by way of non-limiting example only and illustrated by the accompanying drawings in which:

- Figures 1 and 2 (already cited) show schematic views of a shock absorber system for a timepiece according to the prior art;

- Figures 3 and 4 show schematic views of a shock absorber system for a timepiece according to the invention when disassembled and assembled;

- Figures 5 and 6 show different solutions for the elastic means of the shock absorber system of a timepiece according to the invention.

DETAILED DESCRIPTION

The present invention stems from the general inventive concept of providing a simple, easy-to-assemble anti-shock or shock-absorbing device, thereby minimizing the risk of problems occurring during assembly. The shock-absorbing system is arranged to be mounted on at least one bridge and/or main plate of a timepiece movement. The timepiece movement is housed in a timepiece comprising a middle piece enclosed by a back cover and a watch glass.

3 and 4 illustrate a shock absorber bearing or device 100 or an anti-shock system according to a first embodiment. This shock absorber device or anti-shock system 100 is mounted in a base element of a timepiece movement. In particular, the main plate or bridge of the movement is the base element in which the anti-shock system 100 according to the invention is placed. This anti-shock system 100 comprises a support 200. This support 200 takes the form of a cup 201 having a cavity 202 topped by a circumferential edge portion 203 delimited, opposite the cup, by an upper surface 213. This circumferential edge portion 203 also has an outer wall 214 and an inner wall 215. The circumferential edge portion 203 and the base cup 201 define a housing 206 into which the pivot module 400 is inserted. The circumferential edge portion 203 and the base cup 201 may be integral or separate components. The conventional pivot module 400 comprises a mounting seat 401, i.e., a component having a central circular aperture, an outer wall, and an inner wall. A jewel bearing hole component 402, whose diameter corresponds to the central aperture, is inserted into the central aperture. The inner wall includes a shoulder that allows an endstone 403 to be secured. The pivot module 400 is thus placed within the receptacle 206 of the support 200 and engages with the pivoting stem of the spindle.

The anti-shock system 100 also includes an elastic device 300 arranged to cooperate with the pivoting module 400. This allows shocks to be absorbed and the pivoting module 400 to return to its rest position when the stresses exerted by the shocks gradually disappear. The elastic device 300 is fixed to the support 200. Preferably, the elastic device 300 is also placed on the pivoting module 400. The anti-shock system 100 is then inserted into an aperture in the main plate or one of the bridges of the movement.

The elastic means 300 is, for example, in the form of a spring coil 301. The spring coil 301 is of flat type, i.e. it is formed by a strip or ribbon having a width greater than a thickness. The strip or ribbon forming the spring coil 301 is metallic and circular extending along a central axis (C).

In a first embodiment of this spring ring 301, seen in Figure 5, the elastic means 300 take the form of a circular spring ring 301 having arms 302 extending towards the axial center of said spring ring 301. These arms 302 are diametrically opposed and serve to press said pivoting module 400 into the housing 206 of the support 200. The spring ring 301 may comprise two or, more preferably, three arms.

In the second embodiment of the spring coil 301, which is seen in FIG6 , the spring coil 301 comprises inner radial extensions 303 arranged between the annular portions 304. These inner radial extensions 303 are formed by the band forming the spring coil 301, which is bent towards the inside of the spring coil 301. As can be seen in FIG6 , these inner radial extensions 303 are preferably regularly distributed around the circumference of the flat spring coil 301 so that the spring coil 301 can function uniformly. It will therefore be understood that the spring coil 301 can be oriented in any manner relative to the support 200. The spring coil 301 may comprise two or, more preferably, three radial extensions.

To mount and secure the elastic device 300 to the support 200, a bayonet system 500 is used. This bayonet system includes a circumferential shoulder 501 extending from the edge portion 203 toward the center of the support 200. The shoulder 501, together with the support 200 and the edge portion, forms a retaining area 503. The retaining area 503 may also include a circumferential groove 505 to allow the elastic device 300 to be inserted therein. To mount the elastic device, the shoulder 501 includes a notch 507, dividing the shoulder into multiple sections.

Advantageously, the spring coil 301 has a snap-on portion 305 extending away from its axial center. These snap-on portions 305 are configured to retain the spring coil 301. The dimensions of the spring coil 301 and the shoulder 501 are calculated so that the snap-on portions 305 can be inserted into the notches 507 of the shoulder 501. The number of notches is preferably equal to the number of snap-on portions, preferably three. Inserting the snap-on portions into the notches of the shoulder allows the spring coil to be inserted into the retaining area. To position the snap-on portions beneath the shoulder 501, the spring coil simply needs to be rotated. Installation of the spring element occurs after the step of placing the pivot module 400 in its receptacle 206. Therefore, installation of the spring coil causes stress to be applied to the spring coil. This stress is caused by the pivot module tending to push the spring coil outward from the receptacle, while the snap-on portions of the spring coil abut against the shoulder, thereby retaining the spring coil. Of course, it is also possible to have only one notch on the shoulder, but for the spring ring to have two or three snap-fit portions.

The presence of the snap-in portion 305 makes it possible to limit the stress exerted by the shoulder on the spring coil 301, so that the stress is localized in the snap-in portion 305. The snap-in portion 305 is therefore a passive area, i.e. it has no effect on the properties of the spring coil 301. Therefore, the initial properties of the spring coil 301 are not modified by its assembly with the support 200.

Ingeniously, according to the present invention, the portion(s) of shoulder 501 are designed with a beak 509 at each end. These beaks, located at each end of the shoulder portion, function to lock the spring coil. In fact, in operational mode, the shock absorber system works to subject the spring element to more or less stress. However, situations may arise where the spring element is no longer stressed, and the spring coil may shift. This displacement may be a rotational movement of the spring coil itself. Therefore, if the rotation is too great, there is a risk that the snap portion will no longer be relative to the notch, and the spring coil may be removed. The presence of the beak thus advantageously solves this problem by acting as a rotation limiter. During the rotation of the spring coil itself under lower stress conditions, the beak acts as a stop, halting the rotation. The snap portion of the spring coil cannot cease to be relative to the notch, and the spring coil is therefore unable to be removed by itself.

It is conceivable to manufacture the movement element in which the shock absorber bearing 100 is housed and the support 200 as a single component. This movement element and the support 200 are thus a single piece. It is therefore understood that the base element comprises a housing arranged to form the perforated bottom of the cavity and to define the housing 206 in which the pivot module 400 is housed. It is also understood that this second variant can coexist with the first. Indeed, since the bridge or main plate can be of any shape, the arrangement of the mounting area ensures that the fixing device can be installed and thus the pivot module 400 can be retained in the housing.

It is clear that various substitutions and/or modifications and/or combinations obvious to a person skilled in the art may be made to the various embodiments of the invention described above without departing from the scope of the invention as defined in the accompanying claims.

In fact, the pivot module 400 can be formed from a single jewel, or the jewel bore component and the endstone can be integral with each other. It will be appreciated that the jewel bore component and the endstone can be pressed into one another or can be a single component. These possibilities allow the number of components of the shock absorber bearing to be limited.

Claims (8)

1. A shock absorber device (100) for a mandrel of a watch element, the shock absorber device comprising a support (200) including a base cup (201) having a circumferential edge (203) at its top, the circumferential edge being defined opposite to the base cup by a upper surface (213) and including an outer wall (214), the base cup (201) and the circumferential edge (203) together defining a receiving portion (206), the shock absorber device further comprising at least one pivoting module (400) extending along an axis (C), the at least one pivoting module being disposed within the receiving portion and capable of engaging the mandrel, the shock absorber device including a fastening device (500) including a circumferential shoulder (501) extending from the circumferential edge toward an axial center of the base cup, an elastic device being disposed between the at least one pivoting module and the circumferential shoulder to apply stress on the at least one pivoting module. The elastic device is characterized in that it includes a spring coil (301) having at least one radial extension extending toward the center of the spring coil and at least two snap-fit portions (305) extending in opposite directions; the circumferential shoulder includes at least one slot (507) to allow snap-fit assembly of the spring coil; and on both sides of the at least one slot, the circumferential shoulder includes a beak (509) oriented toward the base cup to allow the elastic device to be locked in rotation. 2. The shock absorber device (100) according to claim 1, characterized in that the circumferential shoulder (501) includes three slots (507), and the spring ring includes three snap-fit parts (305). 3. The shock absorber device (100) according to claim 1, characterized in that the at least one radial extension takes the form of at least two arms (302) extending toward the axial center of the spring coil to press the at least one pivoting module into the receiving portion of the support member. 4. The shock absorber device (100) according to claim 3, characterized in that the at least two arms (302) are radially opposite each other. 5. The shock absorber device (100) according to claim 3, characterized in that the spring coil comprises three arms (302) distributed at an angle. 6. The shock absorber device (100) according to claim 1, characterized in that the at least one radial extension takes the form of an inner radial extension (303) disposed between the annular portions (304), the inner radial extension being formed by the strip forming the spring coil bending toward the interior of the spring coil. 7. The shock absorber device (100) according to claim 6, characterized in that the inner radial extension (303) is regularly distributed. 8. The shock absorber device (100) according to claim 6, wherein the spring coil comprises three inner radial extensions (303).