EP0882477A1 - Spring device for a ski binding - Google Patents

Abstract

The clamp return member comprises a coil spring (10) with a resilient plastic material (11) between the coils to increase the force of the spring with the speed of its compression. The plastic material between the spring coils can preferably be a silicone rubber, EPDM or PDMS, and it can be filled with a mineral or organic material such as pyrogenic or colloidal silica, or talc. The plastic can preferably be in the shape of a coil between the spring or a cylinder with the spring embedded in it.

Description

The invention relates to an elastic return device for ski safety binding comprising a spring helical and having a variable stiffness as a function of the loading speed, in which the spring works in compression.

Patents FR 1 454 511, DE 24 15 957, DE 26 34 649, FR 2 424 040, FR 2 625 687 and FR 2 661 334, we know fixings in which a shock absorber is associated to a spring in order to avoid tripping nuisance due to shocks or the like. This shock absorber allows to vary the resistance force at the opening of the binding depending on the solicitation speed, tripping force being raised for violent stresses and, by against, relatively weak for solicitations sweet. This allows to better adapt the response of the front fixing with mechanical resistance characteristics of the leg of a skier, who is able to resist at high intensity stress, but brief, while it risks breaking in the event relatively low intensity loading, but exercising for a relatively long period of time long.

The damper is mounted in series with the spring in the fasteners described in patents FR 1 454 511 and DE 26 34 649. In the fixing according to patent FR 2 642 657, the damper is mounted coaxially inside spring. The use of such devices in a front attachment with two articulated jaws and acting on a tie rod crossing the spring would require a very significant modification of the binding.

A similar arrangement is known from patent FR 2 642 657.

In the patents FR 2 424 040, 2 625 687 and 2 661 334, it is proposed to mount the shock absorber parallel to the spring. This provision allows to leave free inside the spring for the tie rod, but increases the body volume of the fixture and in any case requires also a significant change in the fixation.

Patent application DE 24 15 957 further proposes mount a spring between the two pistons of a shock absorber hydraulic, inside the cylinder.

Furthermore, in all known constructions, the damper is of the hydraulic piston type described in patent FR 1 454 511, that is to say constituted a cylinder and a piston delivering a liquid in this cylinder through a nozzle. It's about therefore always of a conventional damping device separable from the spring and working in parallel or in series with the spring.

In the international patent application WO 92/08527 it is proposed to have a piece of viscoelastic material as a means of dynamic amortization between the nose of a rear fixing piston and the jaw of this fixation.

Definitely deviating from the hydraulic shock absorber versions, the present invention aims to achieve a simple, compact, robust variable stiffness device and capable of being mounted in a front binding or rear without modification of this fixing.

The elastic return device according to the invention is characterized in that it comprises a plastic material fluent interposed between the turns of the spring, such so that the stiffness of the spring increases with speed of its compression.

The plastic material can constitute a helical cord between the turns of the spring or appear like a tubular cylinder in the thickness of which the spring is drowned. In both cases, the interior of the elastic return device remains free for passage of a tie rod, so that the reminder can be mounted in a front tie rod without modification of the fixing, instead of usual spring.

The fluent plastic material can also constitute a full cylinder, at least in its central part, the spring being embedded in the peripheral zone of this cylinder. Such a reminder device can be mounted in a rear binding without modification thereof. The central part of the cylinder essentially constitutes mechanical support for spring and material plastic located between the turns of the spring and, optionally and incidentally, a central shock absorber auxiliary.

The accompanying drawing shows, by way of example, two embodiments of the reminder device according to the invention.

Figure 1 is an axial sectional view along a plane vertical of a front fixing or stop.

Figure 2 is an axial sectional view along a plane vertical of a rear or heel piece.

The front fixing or stop shown in Figure 1 is similar to the attachment described in patent EP 0 295 372 to which reference may be made for more details. This attachment includes a base 1 secured a fixing body 2 on which is mounted a jaw made up of two arms, including arm 3 visible in Figure 1, mounted pivoting independently from each other around two distinct vertical axes formed by rounded vertical edges of the body 2, arranged symmetrically on either side of the plane vertical symmetry corresponding to the section plane, as described in patent EP 0 295 372, so as to be able to move away from each other and come to lean against the end of the shoe by rollers 4 and 5. These arms constitute levers of the first kind articulated on a slightly oblique transverse central axis 6 the end of a tie rod 7 of which a threaded part 7a is screwed into a tubular nut 8 bearing on a socket 9 in the form of a socket. Inside of this stopper is mounted an elastic device of booster consisting of a spring 10 working in compression between the movable stop 9 and a bearing face 2a of the body 2. Between the turns of the spring 10 is wound helically a cord 11 of plastic material fluid with stiffness and variable damping as a function solicitation speed. The radial holding of the cord 11 is provided internally by a telescopic tube in two parts 12 and 13 and, externally, by an envelope 14 of elastic material, such as rubber, or a heat-shrinkable sheath, the ends are folded over the ends of the tube telescopic.

The telescopic tube 12/13 and the casing 14 constitute, preferably a sealed compartment.

The material 11 is preferably a material making part of the family of silicone rubbers or EPDM or PDMS, or the like possibly loaded organic or mineral fillers such as silica pyrogenic talc, colloidal silica. These charges allow to give the material thixotropic properties, that is to say to modify its viscosity to obtain a more or less pasty or gelatinous state. Such material is fluent and has a variable stiffness in depending on the loading speed, in particular compression speed. In compression, the spring 10 thus coated therefore behaves like a spring to variable stiffness.

The variable stiffness device is presented as a tubular element that cannot be fitted instead of the usual spring in a fixing of the type described in patent EP 0 295 372.

Fluid plastic material could also occur in the form of a sleeve in the thickness of which spring 10 would be submerged.

Fluid material could be present on a part only the length of the spring.

The rear or heel piece shown in the figure 2, has, in known manner, a fixing body 15 slidably mounted on a slide, not shown. On this body 15 is articulated a jaw 16 around an axis 17, jaw intended to come to rest on the shoe heel and having a lower part 16a in the shape of a pedal for putting on the shoe pressure on this pedal. During the shoeing, jaw 16 pushes back a piston 18 against the action of an elastic device 19 constituted of a spring 20 embedded in the peripheral region a cylindrical body 21 of fluent plastic material with variable stiffness depending on the stressing speed. This material 21 is of the same type as the material 11. The elastic return device 19 is mounted between the piston 18 and a nut 22 mounted itself on a screw 23 provided with a flange 23a by which it is based on the fixing body 15. The nut 22 drives a cursor 24 for displaying the setting of the precompression of the device 19 by means of the screw 23.

The body 21 has, in its ends, two holes cylindrical axial, one for part engagement tubular central 18a of the piston, part which ensures the attachment of the piston 18 and of the device 19 for mounting, the other axial hole allowing the passage of the screw 23. The body 21 is also provided with an envelope elastic 25.

In the device 19, we find, as in the fixing before, a spring between the turns of which is inserted the fluent plastic material The central area of the body 21 essentially serves as a support for the part of the fluent material located in the spring. Incidentally, this central area can also have a damping effect. In the construction shown, however, this effect is negligible given the very small section through which the hollow portion 18a of the piston 18 rests on the body 21.

It should be noted that the device 19 could be made in a telescopic tubular form as in the case of the front attachment shown.

As with the front attachment, the fluent material could be present, between the turns of the spring, only over part of the length of the spring.

Claims (12)

Elastic return device for safety fastening ski, comprising a helical spring (10; 20) and having a variable stiffness as a function of the loading speed, in which the spring works in compression, characterized in that a material flowable plastic (11; 21) is interposed between the turns of the spring, so that the stiffness of the spring increases with the speed of its compression. Device according to claim 1, characterized in what the fluent plastic is rubber silicone. Device according to claim 1, characterized in what the flowable plastic material is an EPDM. Device according to claim 1, characterized in what the fluent plastic material is a PDMS. Device according to claim 3 or 4, characterized in that the flowable plastic material is loaded by a mineral or organic material. Device according to claim 5, characterized in that the mineral filler consists of fumed silica or talc or colloidal silica. Device according to one of claims 1 to 6, characterized in that the fluent plastic material constitutes a helical cord (11) between the turns of the spring (10). Device according to one of claims 1 to 6, characterized in that the flowing plastic material forms a tubular cylinder in the thickness of which the spring is drowned. Device according to claim 7 or 8, characterized in that the spring and the fluent plastic material are mounted around a telescopic tube (12, 13) and surrounded by an elastic envelope (14). Device according to claim 9, characterized in what the telescopic tube (12, 13) and the envelope elastic (14) form a sealed compartment. Device according to one of claims 1 to 5, characterized in that the fluent plastic material forms a full cylinder (21) at least in its part central. Device according to one of claims 1 to 11, characterized in that the flowing elastic material is present, between the turns of the spring, on a part only the length of the spring.

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