CH712865A2 - Multi-blade shock absorber for a mobile axis of a timepiece. - Google Patents

Abstract

The present invention relates to a shock absorbing device (1) for an axis (2) of a mobile of a timepiece arranged on a support (101), said support being provided with a housing (102) at least partially traversing so that a pivot member (103) cooperating with a tigeron of the axis of the mobile is inserted therein, characterized in that said device further comprises a spring means (110) comprising at least a first blade (112). ) and a second blade (112).

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a shock absorbing device for an axis of a mobile of a timepiece arranged on a support, said support being provided with a housing at least partially through so that an element of pivot cooperating with a tigeron of the axis of the mobile is inserted therein, characterized in that said device further comprises a spring means comprising at least a first blade and a second blade.

BACKGROUND

In timepieces, there are shock absorbing or shockproof systems to protect the axes of the mobile. A first system is a lyre system that is to say that the plate or bridge is provided with a hole through which the shank of an axis can pass. This hole serves as a housing for a support, pierced at its center, in which a kitten is arranged. This kitten carries a pierced stone and a counter-pivot stone, the whole being put under stress by a lyre spring arranged between the support, which has flanges serving as points of support, and the kitten. Another system is the fall arrest system in which the pivots of the balance are made so as to give them the shape of a cone and hold them in place by a small cup of corresponding shape, mounted on a leaf spring.

[0003] The horological impactors are generally constituted by mechanical springs and are still dimensioned in the old fashion, following practical rules considered as the best compromise between mechanical stability during operation and resistance to mechanical deformations.

In particular, the shock of the sprung balance, parachutes and lyres, are sized to not be activated until relatively large shock accelerations (between 200 and 500 times the gravity), thanks to the preload of the spring. Beyond this threshold value, the spring can be deformed and absorb some of the impact energy. However, because of the low mechanical damping of the metal blades used as shockproof, most of the energy is returned to the balance. The local deformation of the pendulum pivot is therefore very likely, already for relatively small shocks. This deformation, which has a considerable impact on the chronometric accuracy of the watch, is generally neglected because the standard certifying the chronometric stability of a COSC watch after a shock of one meter is not severe (60 s / j of difference).

There is therefore a need in improving the chronometric stability of the watch after a shock.

SUMMARY OF THE INVENTION

The invention aims to overcome the disadvantages of the prior art by proposing to provide.

For this purpose, the present invention relates to a shock absorbing device for an axis of a mobile of a timepiece arranged on a support, said support being provided with a housing at least partially through so that a pivot member cooperating with a tigeron of the axis of the mobile is inserted therein, characterized in that said device further comprises a spring means comprising at least a first blade and a second blade spaced apart from each other extending from the support and in that the first blade is in contact with said pivot member and exerting a prestress.

In a first advantageous embodiment, said blades extend in parallel fashion.

In a second advantageous embodiment, said blades extend in the same direction.

In a third advantageous embodiment, said blades extend in a convergent direction, the point of intersection of the blades being located opposite the pivot element.

In a fourth advantageous embodiment, said pivot element consists of a pivot stone free axially in said housing, the pivot stone comprising a recess in which the shaft of the axle is inserted.

In a fifth advantageous embodiment, said pivot element consists of a free kitten axially in said housing, a pierced stone and a counter-pivot stone being driven into said kitten.

In a sixth advantageous embodiment, said pivot member and the first blade form one and the same piece.

In a seventh advantageous embodiment, said pivot member is a pivot stone driven into a hole arranged on the first blade.

In another advantageous embodiment, said first blade and the second blade have different stiffnesses, the first blade being less rigid than the second blade.

In another advantageous embodiment, the spring means further comprises a third blade, the third blade being more rigid than the second blade.

In another advantageous embodiment, the difference in stiffness between the different blades is obtained by differentiating the material between the blades and / or having elastic blades of different dimensions / shapes.

In another advantageous embodiment, the resilient blades are fixed to the support by means of a pad provided with washers arranged between two resilient blades to allow their spacing.

In another advantageous embodiment, the stud is attached to the support.

In another advantageous embodiment, the stud is monobloc with the support.

In another advantageous embodiment, said housing is completely through and has an inner slice from which the elastic blades extend.

BRIEF DESCRIPTION OF THE FIGURES

The objects, advantages and features of the invention will appear more clearly in the following detailed description of at least one embodiment of the invention given solely by way of non-limiting example and illustrated by the accompanying drawings in which: :

Figs. 1 and 11 show a diagram of a first device embodiment according to the invention;

Figs. 2 and 3 show a schematic view of different embodiments of the spring means according to the invention;

Figs. 4 to 6 show a diagram of a second device embodiment according to the invention and one of its variants;

Fig. 7 represents a variant of the different embodiments;

Figs. 8 to 10 represent variants of the invention.

DETAILED DESCRIPTION

The present invention proceeds from the general idea of providing a shock absorber system having a progressiveness in the absorption of shocks.

In FIG. 1, a shock absorber device 1 or shockproof system according to a first embodiment is shown. This shock absorbing device or shockproof system 1 is mounted in a base element 101 or support a movement of a timepiece. In particular, the plate or the bridges of the movement are the basic element in which the shockproof system 1 according to the invention is placed. This shock absorbing device is used to dampen the shocks of an axis 2 of a timepiece mobile: a wheel or a wheel or escape wheel.

This base element or support 101 is provided with an opening 102 facing the axis 2 to be damped. The axis 2 cooperates with a pivot member 103. This pivot member 103 may be a pivot stone comprising a recessure for the shaft tigeron engages. This pivot stone can be placed directly in the opening or via a kitten so that it can move at least axially during an impact.

The shock absorbing device further comprises a spring means 110 for damping the axis of the moving body.

These spring means, visible in FIG. 2, advantageously comprise a plurality of resilient blades 112. These blades are arranged between them to be superimposed. In this first embodiment, the resilient blades extend from a stud 114. This stud 114 is a piece which is fixed, by screwing, gluing, welding, or soldering, to the plate or to the pendulum bridge. The elastic blades therefore extend from one of their ends, fixed to the stud. The blades 112 are spaced apart by means of washers 115 in order to be able to deform independently of one another and to present an interlime space (preferably adjustable). This interlime space may be constant or be, at the free end of the blades, larger or smaller than the space at the level of the stud as can be seen in FIGS. 9 and 10. These blades can extend in the same direction or not. In the case where the blades extend in different directions, the attachment points of the different blades are spaced so as to have the blades that converge, the cross points of the different blades being ideally opposite the pivot stone as shown in fig. 8.

The assembly 110 formed by the resilient blades 112 and the pad 114 is then arranged for one of the resilient blades, in particular the resilient blade facing the pivot member, exerts a prestressing. By this is meant that the resilient blade is in contact with and presses against the pivot member. This configuration with several blades allows for a progressive shock resistance, allowing to dissipate a greater amount of energy (shock) by multiple 'impacts' and the use of highly dissipative materials.

In a first embodiment visible in FIGS. 1 and 2, the blades forming the spring means 110 are identical in size and material. The operation of this set is as follows. During an impact, the apparent rigidity felt by the pendulum (or any other mobile watch), gradually increases in identical discrete steps depending on the deflection arrow (so depending on the energy of the shock).

The discontinuity of rigidity occurs when one of the blades 112 is sufficiently flexed to abut against the next blade: at this moment, the energy of the impact (kinetic energy of the balance) is partially dissipated by an impact mechanism (characterized by a certain coefficient of restitution). The discontinuity of rigidity thus makes it possible to increase the dissipation of energy during the impact.

In a second embodiment, visible in FIG. 3, the blades 112 are different in materials and sizes. Indeed, the dissipative effect and the stiffness profile can be optimized by using blades of geometries or different materials.

The use of different materials can allow to introduce highly dissipative materials (such as some copper or aluminum variant) together with perfectly elastic materials (not having any dissipation), such as silicon, silicon carbide, silicon nitride or metallic glasses.

In this case, the (e) blade (s) elastic 112 allow the perfect repositioning after the shock, while the blades 112 dissipative materials can reduce the energy of the impact suffered by the pivot of the balance. This double behavior is impossible to achieve with a single blade, because generally highly dissipative materials undergo very easily plastic deformations. Advantageously, the main blade 112, resting directly on the pivot stone, must have dimensions between the following intervals:

Length: 10 mm-20 mm

Width: 3.2 mm-2 mm

Thickness-0.05 mm-0.5 mm: The other blades 112 can be adapted outside these ranges, depending on the materials used, the weight of the balance and the other geometric parameters of the movement.

In the case of the size change, the goal to be achieved is the same, that is to say, to modify the rigidity of the blades 112 in order to obtain an adequate response to a shock.

Preferably, the first elastic blade 112, that is to say the blade 112 in contact with the pivot member 103 is designed to be quite elastic which plasticizes rather late and other blades 112 more rigid allowing better dissipation shock energy.

In a second embodiment, the resilient blades 112 are arranged to replace the pivot member 103. This means that the elastic blades 112 and the pivot member 103 form a single assembly.

For this, these elastic blades 112 are arranged so that the first blade that is to say the blade closest to the base member (platinum or bridge) serve as a pivot element 103. For both solutions are possible.

The first solution, visible in FIG. 4, is to directly use the first blade 112 as a pivot element. It is understood by this that the elastic blade 112 is made of a first material and that the tigeron of the axis comes into contact with this first material. The elastic blade 112 may be provided with a recess facilitating the placement of the axle shank.

In a second solution visible in FIG. 5, the first elastic blade 112 carries a pivoting element 103. For this, the elastic blade 113 has a hole, through or not in which a pivoting element is arranged.This pivoting element is preferably a pivot stone in a material This pivot stone will be fixed by gluing, welding, soldering or any other possible fastening method.

This second solution advantageously makes it possible to guard against possible incompatibility problems. Indeed, the use of a ruby stone guarantees a limitation of the friction at the level of the tigeron of the axis and thus a better efficiency.

In a variant of this second embodiment shown in FIG. 6, the elastic blades 112 extend inside the opening of the base member 101, ie the plate or the bridge. In this case, the opening 102 has a slice or inner wall from which the resilient blades 112 extend.

This variant advantageously allows to be more compact by directly integrating the blades 112 in the opening 102 which limits the thickness of the system.

In a variant of these two embodiments shown in FIG. 7, the resilient blades 112 forming the spring means 110 are monoblock with the support member 101. For this, several possibilities are offered. The first is to use metal glasses known for their shaping properties when heated between their glass transition temperature Tg and their crystallization temperature Tx.

Another solution is to achieve the set formed spring means and the silicon base member using a Liga or drie method.

It will be understood that various modifications and / or improvements obvious to those skilled in the art can be made to the various embodiments of the invention described in the present description without departing from the scope of the invention.

Claims (15)

Indeed, it is possible to imagine an increase in overall damping by the addition of a viscoelastic material or a viscous fluid between two or more blades. Furthermore, it is also possible for the opening 102 of the base member to be used to drive a support block 200 provided with a housing 201 and a through hole 202 to accommodate the housing. pivot member 103 which will be at the bottom of the housing of the support block of the opening. The pivot element which will be a simple stone or a kitten 204 with a pierced stone 205 and a counter pivot stone 206 will rest in the bottom of the support block as shown in FIG. 11. Claims 1. shock absorbing device (1) for an axis (2) of a mobile of a timepiece arranged on a support (101), said support being provided with a housing (102) at least partially through so that a pivot element (103) cooperating with a pivot of the axis of the mobile is inserted therein, characterized in that said device further comprises a spring means (110) comprising at least a first blade (112) and a second blade (112) spaced apart from each other extending from the support and in that the first blade is in contact with said pivot member and exerting a prestress. 2. Device according to claim 1, characterized in that said blades extend in parallel manner. 3. Device according to one of the preceding claims, characterized in that said blades extend in the same direction. 4. Device according to one of claims 1 to 2, characterized in that said blades extend in a convergent direction, the point of intersection of the blades being located opposite the pivot element. 5. Device according to one of the preceding claims, characterized in that said pivot member (103) consists of a pivot stone axially free in said housing, the pivot stone comprising a recess in which the rod of the axis is inserted. 6. Device according to one of claims 1 to 4, characterized in that said pivot element consists of a free kitten (204) axially in said housing, a pierced stone (205) and a stone against pivot (206) being driven in said kitten. 7. Device according to one of claims 1 to 4, characterized in that said pivot member and the first blade form a single piece. 8. Device according to one of claims 1 to 4, characterized in that said pivot member is a pivot stone (103 ') driven into a hole arranged on the first blade. 9. Device according to one of the preceding claims, characterized in that said first blade and the second blade have different stiffnesses, the first blade being less rigid than the second blade. 10. Device according to one of the preceding claims, characterized in that the spring means further comprises a third blade, the third blade being more rigid than the second blade. 11. Device according to claims 9 or 10, characterized in that the difference in stiffness between the different blades (112) is obtained by differentiating the material between the blades and / or having elastic blades of different sizes / shapes. 12. Device according to one of the preceding claims, characterized in that the resilient blades are fixed to the support by means of a stud (114) provided with washers arranged between two resilient blades to allow their spacing. 13. Device according to claim 12, characterized in that the stud is attached to the support. 14. Device according to claim 12, characterized in that the stud is integral with the support. 15. Device according to claim 14, characterized in that said housing is completely through and has an inner edge from which the elastic blades extend.