CH712864A2 - Shock absorber with membrane. - Google Patents

Abstract

The present invention relates to a shock absorbing device (1) for an axis (200) of a mobile of a timepiece arranged on a support (100), said support being provided with an opening (102) so that said axis can move in translation in said opening, said axis comprising, at each end, a tigeron (201) cooperating with a pivoting element (300).

Description

Description

SHOCK ABSORBER WITH MEMBRANE

The present invention relates to a shock absorber device for an axis of a mobile of a timepiece arranged on a support, said support being provided with an opening so that said axis can move in translation in said opening, said axis comprising, at each end, a tigeron cooperating with a pivoting element.

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 beam 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 a shock absorbing system having a progressiveness in the absorption of shocks while preventing the tigeron is exposed to the energy of the shock .

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 an opening so that said axis can move in translation. in said opening, said axis comprising, at each end, a tigeron cooperating with a pivoting element, characterized in that said device further comprises at least a first elastic membrane spring arranged in the first opening, said first membrane being pierced with a through-hole through which said axis passes, said axis comprising at least a portion whose diameter is greater than that of the through-hole of said first membrane so as to serve as an abutment of said axis during a consecutive movement consecutive to a shock .

In a first embodiment, the axis has a first diameter and comprises, at each end, an area of a second diameter from which the tigeron extends, the second diameter being smaller than the first diameter. diameter.

In a second embodiment, the transition between the zone of first diameter and the zone having a second diameter is formed to form a shoulder.

In a third embodiment, the axis further comprises, in the zone having a second diameter, a first radially extending peripheral portion, said projecting portion being spaced from the shoulder so that the diaphragm spring can be seated. inserting into the space between said first projecting portion and said shoulder.

In a fourth embodiment, the device further comprises a second diaphragm spring arranged in the first opening so that the first diaphragm spring and the second diaphragm spring are located on either side of said first diaphragm spring. protruding part.

In a fifth embodiment, the axis further comprises a second projecting portion arranged so that the first projecting portion and the second projecting portion are located on either side of the second diaphragm spring.

In a sixth embodiment, the thickness of said diaphragm or membrane spring is between 5 pm and 50 pm.

In another embodiment, the membrane spring or springs may be made of a material selected from the list comprising: silicon, crystalline silicon carbide, ceramic silicon carbide, silicon nitride and metallic glass.

In another embodiment the membrane spring or springs may be made of a stretchable material of the polymer or elastomer resin type.

In another embodiment, the pivoting element is a fall arrest system.

In another embodiment, the pivoting element is a kitten and lyre system.

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 2 show a schematic view of different forms of the first embodiment of the invention;

Figs. 3 and 4 show a schematic view of the operation of the first embodiment of the invention;

Figs. 5 and 6 show a diagram of a second device embodiment according to the invention;

Figs. 7 and 8 show a diagram of a third device embodiment according to the invention and one of its variants.

DETAILED DESCRIPTION

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

In figs. 1 and 2, a shock absorbing 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 member 100 of a timepiece movement. 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 impacts of an axis or shaft 200 of a timepiece mobile: a wheel or a balance wheel or an escape wheel.

This base element 100 is provided with an opening 102 opposite the axis 200 to be damped. The axis 200 cooperates with a pivot member 300 via tibber 201 arranged at each end of the axis 200. This pivot member 300 may be in several forms.

A first form is called a fall arrester in which the pivots or tigeron 201 of the axis 200 of the mobile are made so as to give them the shape of a cone and hold them in place by a small cup 310 of corresponding shape, mounted on a leaf spring 312 as shown in FIG. 1. The leaf spring 312 may be mounted on a support 314 fixed to the plate 100.

A second form consists of a pivot element kitten and lyre. Such an element comprises a kitten 324 placed in a housing 322 of a frame 320. In the kitten 324, a pierced stone 325 and a counter pivot stone 326 are inserted. The kitten is then retained in the housing of the frame via a spring 327 lyre shape deforming to absorb shocks as shown in FIG. 2.

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

These spring means 110, visible in FIG. 2, advantageously comprise at least one first diaphragm spring or diaphragm 112. Such a diaphragm spring 112 is arranged at the opening 102 of the base member 100 in which the axis 200 fits.

Such a diaphragm spring 112 is used to prevent the most energetic impact during a shock is suffered by the pivot / tigeron 201 of the axis of the mobile and thus to find an innovative solution for absorbing and dissipate most of the shock energy by the impact of another part of said axis.

As such, the diaphragm spring 112 according to the invention is arranged at the opening 102 of the base member 101. This membrane comprises a through hole 113 in which the axis takes place. The membrane 112 is designed to cooperate with the axis and, more particularly, with a shoulder 202 of said axis. Indeed, the axis 200 of the watch mobile comprises at each end a tiger 201 for its pivoting. Depending on the diameter of said axis 200, it is not necessarily wise to have an end directly provided with a tungsten 201. As a result, the axis 200 may be designed so as to have a main portion having a first diameter D1 and at the ends, a portion of a second diameter D2 smaller than the diameter of the main portion. Such narrowing may be linear or abrupt to form a shoulder 202.

During normal operation (in the absence of shock), there is no contact between the membrane and the axis of the watch mobile as shown in FIG. 3.

Claims (11)

During an impact having an axial contribution as shown in FIG. 4, the axis 200 moves and arms the traditional anti-shock 300 (lyre or parechute) but, after a relatively short axial stroke (in the Z direction), the axis 200, via its shoulder 202, abuts against the membrane 112 'with a liner'. The movement of the axis 200 of the mobile thus begins to deform the membrane 112 which absorbs a considerable part of the impact energy by its deformation in extension (in the case of a stretch membrane) and / or flexion, in the case a standard thin elastic membrane. Therefore, the tigeron 201 is no longer the part of the axis that stores the maximum energy. The risks of rupture of the tigeron 201 are therefore reduced. The thickness of the membrane 112 is advantageously between 5 microns and 50 microns (depending on the material used) and the membrane 112 may be made of silicon, silicon carbide (crystalline or ceramic), silicon nitride (in these three cases it can be manufactured by DRIE technology) or metallic glass. In a particularly advantageous embodiment, the membrane 112 may be made with a stretching material with high energy dissipation, for example such as elastomeric polymers or resins (especially silicone, but also PVC, PVDC, PE, etc.). . In this case, the elastic properties in the direction of deformation Z, will depend on the elongation applied in the XY plane, which is advantageously between 2% and 15% of the dimension of the membrane in the same direction of the elongation. The opening 113 of the membrane 112 (within which the balance shaft is located) may be of circular, square, rectangular or polygonal geometry. The membrane 112 may also not be completely closed around the axis of the mobile. The dimension of the opening 113 is such that the projection of the membrane in the XY plane is partially superimposed on the projection of the axis 200 of the moving body in the same plane, the superposition being ensured by one or more portions of the axis. extending over a diameter substantially greater than the diameter of the tigeron at the end of the axis dedicated to pivoting. This is either a linear shrinkage or at least one shoulder. In a second embodiment shown in FIG. 5, the shaft 200 is made to have a plurality of spokes and the membrane 112 is activated independently of the direction of impact. Such an embodiment consists of having a first shoulder 202a to make a transition between two zones of different diameters, the diameter being reduced towards the end. The second shoulder 202b consists in providing, at the region of smaller diameter, a radially extending peripheral portion 203 protruding. The two shoulders 202a, 202b are then arranged so that a space 204 exists between them. This space 204 is used for the membrane 112 to be placed there. Therefore, regardless of the axial displacement of the shaft 200 of the mobile following an impact, at least one membrane 112 will be biased to dissipate the energy of said shock. In the presence of two membranes 112, positioned at each end of the shaft 200 of the mobile, the absorption of the shock energy is maximized since during an impact, the two membranes will be biased as shown in FIG. . 6. In a third embodiment shown in FIG. 7, it is expected to have several membranes 112 for each end. In one embodiment with first and second membranes 112 for each end, the mobile shaft is designed similarly to that of the second embodiment. Such a shaft 200 of mobile is to have a first shoulder 202a to make a transition between two zones of different diameters, the diameter being reduced in approximates the end. The second shoulder 202b consists in providing, at the region of smaller diameter, a radially extending peripheral protrusion. The two shoulders 202a, 202b are then arranged so that a space exists between them. This space is used so that a first membrane can be placed there. The second membrane 112 is then placed on the other side of the protruding portion 203 so that the two membranes 112 are placed on either side of the projecting portion. Thus, in the case of a shock pushing the tigeron to exert a stress on the conventional anti-shock system, the displacement of the axis of the mobile causes a contact between the first shoulder and the first membrane and between the projecting portion and the second membrane 112. These two membranes 112 then deform to dissipate the energy of the shock, the latter being distributed over the two membranes. By cons, in the case of a shock pushing the tigeron to move away from the conventional anti-shock system, the movement of the axis of the mobile causes a contact between the projecting portion and the first membrane. It may of course be provided several projections 205 as shown in FIG. 8 and other membranes. The absorbed energy can be maximized and the apparent rigidity 'seen' by the balance during the shock can be increased depending on the energy of the shock. 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 1. shock absorbing device (1) for an axis (200) of a mobile of a timepiece arranged on a support (100), said support being provided with an opening (102) so that said axis can move in translation in said opening, said axis comprising, at each end, a tigeron cooperating with a pivoting element (300), characterized in that said device further comprises at least a first elastic membrane spring (112) arranged in the first opening, said first membrane being pierced with a through hole (113) through which said axis passes, said axis comprising at least one portion whose diameter (D1) is greater than that of the through hole of said first membrane so as to serve abutting said axis during a movement following a shock. 2. shock absorbing device according to claim 1, characterized in that the axis (200) has a first diameter (D1) and comprises, at each end, an area of a second diameter (D2) from which the tigeron extends, the second diameter being smaller than the first diameter. Shock absorbing device according to claim 2, characterized in that the transition between the first diameter zone (D1) and the zone having a second diameter (D2) is formed to form a shoulder (202). 4. shock absorbing device according to claim 3, characterized in that the axis (200) further comprises, in the zone having a second diameter (D2), a first radially extending peripheral projection portion (203), said protruding portion being spaced from the shoulder (202) so that the diaphragm spring (112) can be inserted into the space between said first protrusion and said shoulder. 5. A shock absorbing device according to claim 3, characterized in that it further comprises a second diaphragm spring (112) arranged so that the first diaphragm spring and the second diaphragm spring are located on both sides. another of said first protrusion (203). 6. shock absorbing device according to claim 5, characterized in that said axis further comprises a second projecting portion (205) arranged so that the first protruding portion (203) and the second projecting portion are located on the side and other of the second diaphragm spring (112). 7. shock absorbing device according to one of the preceding claims, characterized in that the thickness of the membrane spring or is between 5 pm and 50 pm. 8. Shock absorbing device according to one of the preceding claims, characterized in that the membrane spring or springs can be made of a material selected from the list comprising: silicon, crystalline silicon carbide, ceramic silicon carbide, nitride of silicon and metal glass. 9. shock absorbing device according to one of claims 1 to 7, characterized in that the membrane spring or springs may be made of a stretchable material of the polymer or elastomeric resin type. 10. Shock absorber device according to one of the preceding claims, characterized in that the pivot element is a fall protection system. 11. shock absorbing device according to one of claims 1 to 9, characterized in that the pivoting element is a kitten and lyre system.