EP0580935B1 - Improvement to an amortizement device for a ski - Google Patents

Abstract

Ski (1) equipped with at least one shock-absorbing device intended to dampen the vibrations of a ski, characterised in that it consists of at least one flexion blade (13) which comprises a first part (131) fastened rigidly to the ski and a second part (130) connected to the ski in a movable manner longitudinally by shock-absorbing means (14) of the type with viscous friction. <IMAGE>

Description

The present invention relates to a damping device for skiing, such as an alpine ski, a cross-country ski, a monoski or a snowboard. It relates more particularly to an improvement of this type of device, and also relates to a ski equipped with it.

We already know different types of skis made thanks to a more or less flexible structure. There are many variations, which consist of an elongated beam whose front end is curved upward to form a spatula, the rear end also being more slightly to form the heel.

Current skis generally have a composite structure in which different materials are combined so that each of them intervenes optimally, taking into account the distribution of mechanical stresses when using the ski. Thus, the structure generally comprises peripheral protection elements, internal resistance elements to resist the flexural and torsional stresses, and a core. These elements are assembled by gluing or by injection, the assembly generally being carried out hot in a mold having the final shape of the ski, with a front part strongly raised in a tip, a rear part slightly raised in the heel, a central arched part. .

Despite the manufacturers' concern to manufacture good quality skis, they have not, to date found a high performance ski satisfactory in all conditions of use.

Current skis have a certain number of drawbacks and in particular that of poor behavior on snow during oscillations due to vibrations or flexing of the ski. Indeed, the persistent vibrations cause a loss of grip and therefore, poor skiing. It is therefore very important to dampen vibrations, so solutions have already been proposed. Let us note, for example, the solutions proposed in French patent applications No. 2,503,569 and No. 2,575,393. However, these damping devices have in fact only very minor and imperceptible effects for the skier.

Document EP-A1-521 272 (published on 07.01.83) belonging to the applicant relates to a damping device comprising at least one flexion blade fixedly connected by a first part to the ski and the second part of which is movably connected by means of dry friction.

The present invention seeks to remedy the various drawbacks mentioned above and proposes a particularly simple, effective and reliable solution to the problems of damping vibrations.

Thus, the ski according to the invention comprises at least one damping device intended to damp the vibrations of a ski, constituted by at least one flexion blade which comprises a first part rigidly fixed to the ski and a second part so connected movable longitudinally by damping means. The damping means are of the viscous friction type, and consist of at least one layer of viscous material chosen from mineral or organic grease. The second part in contact with the damping means is movable by sliding in a stirrup connected to the ski.

According to an additional characteristic, the second part is spaced longitudinally from the first part.

According to another characteristic, the stirrup has a U shape with a sliding housing open downwards. According to another arrangement, the stirrup comprises peripheral walls and is in the form of a sealed housing. The tightness guarantees a constant damping value over time (with equal use conditions).

In another embodiment of the invention, the caliper comprises an adjustable or non-pneumatic, hydraulic or elastic pressure member such as a spring which acts on the blade. An adjustable pressure member has the advantage of being able to increase or decrease the damping value according to the use to be made of the ski and according to the atmospheric and temperature conditions. In addition, it allows to correctly adjust the same value of each ski constituting the pair.

According to preferred embodiments, the bending blade is a blade that is either metallic, aluminum, steel, or a composite material.

The invention also relates to the device intended to equip the ski and which comprises a flexion blade and a stirrup comprising a viscous material chosen from mineral or organic grease.

According to one of the embodiments, the flexion blade is disposed and fixed to the upper surface of the ski, while in another embodiment, it is arranged in the structure of the ski.

The blade can extend at the front of the ski between the front contact point and the binding mounting area, but it can also extend much further back. The stirrup being fixed on the ski in front of the binding mounting area, or extending throughout the binding mounting area and serving as their support.

Of course, the flexible blade can extend at the rear of the ski between the rear contact point and the binding mounting area, or extend forwards much further.

It goes without saying that the ski according to the invention can have several damping devices.

Other characteristics and advantages of the invention will emerge from the description which follows with reference to the appended drawings which are given only by way of nonlimiting examples.

Figures 1 to 6 show a first embodiment.

Figure 1 is a side view.

Figure 2 is a top view.

Figure 3 is a cross section along T1, on a larger scale.

Figure 4 is a partial longitudinal section on a larger scale.

FIGS. 5 and 6 show in side view how the device works, FIGS. 5a and 6a being partial representations on a larger scale of FIGS. 5 and 6.

Figures 7, 8 and 9 are views similar to Figure 1 showing three other embodiments.

Figure 10 is a cross-sectional view of a ski whose damping device is embedded.

Figure 11 is a view similar to Figure 3 illustrating a variant.

Figure 12 is a partial side view showing an alternative embodiment.

Figures 13 to 15 are side views illustrating three types of damping devices that have been tested.

Figure 16 is a view similar to Figure 1 illustrating a variant.

FIG. 17 is a partial view on a large scale of the end of the damping device at the level of the stirrup.

Figure 18 is a view similar to Figure 17 illustrating a variant.

FIG. 19 is another variant of FIG. 17.

FIG. 20 is a perspective view of an element of the device in FIG. 19.

The ski (1) comprising the device consists of an elongated beam (100) having its own distribution of thickness, of width and therefore its own stiffness. It comprises a central part (2) also called a mounting area for the bindings (3, 4) intended to retain the boot on the ski, the front binding (3) being commonly called a stop, while the rear binding (4) is called usually heel. The front end (5) of the ski (1) is raised to form the tip (6), while the rear end (7) is also raised to form the heel (8) of the ski. The beam further comprises a lower sliding surface (9) and an upper surface (10). Note that the contact of the lower surface (9) with the snow takes place between the front contact point (11) and the rear contact point (12) corresponding to the places where said lower surface begins to rise.

Figures 1 to 6 show a first embodiment according to which the damping device according to the invention consists of a bending blade (13) disposed at the front on the upper surface (10) of the ski (1). According to the invention, said flexion blade is fixed to the ski by a first part constituted by the front end (131) of the blade, while it is connected to it by a second part, by damping means (14 ), of the viscous friction type. The fixing of the first part (131) of the blade on the ski is a fixed, rigid connection, produced for example by screws (16), by gluing or by welding. It should be noted that the blade is flexible in bending and does not generate additional static stiffness (or negligible stiffness compared to the rest of the ski). According to this embodiment, the second part of the blade (13) is constituted by the rear end (130) movable longitudinally relative to the ski, and which is connected to it by friction means (14) of viscous type. The viscous type friction means (14) are a viscous mobile connection with the ski, arranged on the top of the ski, so that the rear part (130) linked to the ski in a viscous mobile manner is spaced longitudinally at a distance ( D) of the front part (131) rigidly fixed to the ski.

For this purpose, the friction and absorption means (14) consist of a sheath or stirrup (145) fixed to the ski by screws (15) comprising a sliding housing (144) for the bending blade, housing filled a viscous material such as silicone type grease. The sheath being constituted by a U-shaped stirrup, fixed to the ski and comprising an upper wall (146) and two side walls (148, 149). Thus, the sliding part (130) of the bending blade (13) is in the sheath, completely surrounded by a layer of grease forming a viscous film: an upper layer (140), a lower layer (141) and two side layers (142, 143). The sheath (145) has the general shape of a U open towards the bottom, forming the sliding housing (144) and fixed to the ski by screws (15) in front of the area for mounting the bindings, and in particular the front binding (3), while the front part (131) of the flexion blade (13) is fixed to the ski at the front end of the latter and for example behind its front contact zone (11). The rear end (130) of the flexion blade can thus move longitudinally inside the sheath according to F1 and F2 relative to the body (2) of the ski, as shown in Figures 5, 5a, 6 and 6a .

Figures 5, 5a, 6 and 6a schematically show the operation of depreciation. Figure 5 shows the ski in the rest state, and Figure 6, during bending. During bending, it is found that there is relative movement towards the rear of the rear end (130) of the blade relative to the friction means (14). According to the diagrammatic representation, the rear end has moved rearward along F2 by a relative distance (d) and this movement has been braked by layers of viscous material (140, 141, 142, 143). The braking and therefore the damping taking place of course also in the relative relative displacements, that is to say according to F1, in the movements of return to the initial position and in counter-jib.

It goes without saying that the bending blade can be longer or shorter and for example be as shown in FIG. 7. According to this variant, the blade (13a) extends backwards, much further than previously, to be retained by the friction means (14a) constituted by a sleeve (145a) extending over the entire mounting area (200) of the two fasteners (3, 4). Of course, said sheath (145a) is of the type of that illustrated in the first embodiment. However, the sleeve (145a) serves, in this embodiment, as a support for the fasteners (3, 4) to which they are fixed, instead of being fixed on the upper surface (10) of the part (100) of the ski proper.

Of course, it is not necessary for the flexion blade (13) to extend beyond the level of the front attachment (3). Indeed, the device could be like that illustrated in FIG. 8, which represents another variant according to which the means for retaining the blade (13b) and for damping consist of a sheath (145b) which only extends locally under the front fixing (3). Note that the bending blade (13) is made of aluminum, steel or a composite material, of width (l) between 10 and 45 millimeters, and of thickness (e) from 0.5 to 8 millimeters. It is fixed to the ski between the zone (11) of the front contact point and the binding (3), while the length (L1) of the sheath is between 2% and 100% of the length (L2) of said blade . In addition, the thickness of the viscous film can be between 0.1 and 1 millimeter.

Of course, the damping device according to the invention such as that described above, can be arranged at the rear of the ski as it appears in FIG. 9. Thus the rear end (130) of the blade (13) is fixed to the rear of the ski and extends towards the front so that its front end (131) is linked to the ski movably longitudinally by the friction means (14). Said means being constituted by a sheath (145c) identical to the sheath (145), but disposed under the rear attachment (4), and which serves as its support. Of course, the blade (13) can extend forwards beyond the rear attachment (4) and as far as the front attachment (3).

In the various embodiments proposed in FIGS. 1 to 9, the damping device is arranged outside the structure proper of the ski. However, of course, it would not go beyond the scope of the invention if it was embedded in the ski, as shown schematically in FIG. 10.

The skis most often consist of a core (101) covered by one or more upper (102) and lower (103) reinforcing layers. The top of the ski being generally covered by a protective layer (104), while the underside comprises a polyethylene slip layer (105). Thus in the embodiment of Figure 10, the damping device is embedded in the ski and an upper plate (106) creates the necessary sliding housing and seals said device by completely isolating it from the outside.

It goes without saying that the bending blade which, in the proposed embodiments, has a rectangular section, can take any type of shape. It can for example be constituted by a cylindrical rod. In particular, it can be provided that the blade is designed so as to be predisposed to buckling down rather than upwards in order to avoid any blockage of the device. Different solutions are within the reach of those skilled in the art such as that which consists in lowering the position of the neutral fiber of the blade by giving it a form of Omega in its central part for example (not shown).

Figure 11 is a view similar to Figure 3 illustrating a variant in which the sleeve (145d) comprises a lower wall (147) parallel to the upper wall (146).

Figure 12 illustrates in side view, schematically, another variant in which the lower layer (141) of the viscous material extends beyond the sheath and under the entire blade.

It goes without saying that the sheath can be fixed to the ski by other means than screws. in fact, it can also be glued or welded. Note also that the ski of the invention can have several damping devices, such as for example two devices: one being arranged at the front, as illustrated in FIG. 1 or 8, and the other at the rear , as shown in Figure 9.

By way of example, damping tests were carried out on a 2010 mm ski with in a first case (FIG. 13), a flexion blade (13) of short length (L2) equal to 230 mm, the sheath (145) having a length (L1) of about 100 mm and a width of 29 mm. The contact surface between the two sides of the blade and the sheath constituting the active viscous friction surface is approximately 2 × (100 × 29), that is to say approximately 5800 mm ² (neglecting the friction at the edges of the blade). The fluid used has a viscosity of about 400 poise. The distance (De) from the area fixed to the rear of the ski is 1660 mm. The damping test is carried out on the ski being clamped in its center over a distance (B) of 300 mm; the spatula is loaded with a mass (M) of 20 kilograms-weight which is suddenly released and the damping of the vibrations thus created is measured. The depreciation value obtained in this case is around 3.2% poise.

In a second case (Figure 14) the parameter that we vary from the previous case, is the length of the blade (L2) which is equal to 1060 mm instead of 230 mm. The damping surface remains identical, i.e. 5800 mm ² . Under these conditions, there is a depreciation value of around 6.7% poise.

The comparison of the damping values of these first two cases therefore demonstrates the importance of the length of the blade on the efficiency of the entire damping device.

In a last example (FIG. 15), the length (L1) of the sheath (145) is increased compared to the previous case so as to increase the active damping surface. The length (L1) is equal to 930 mm instead of 100 mm. The damping surface is approximately 2 x (930x29) = 53,940 mm ² . All other parameters are kept constant compared to the previous cases. The depreciation value reaches 8.2% poise. It should therefore also be noted the importance of the active contact surface on the damping effect obtained.

The active surface can be reduced for identical damping values, if provision is made to apply a means exerting pressure on the blade at the level of the sheath, as will be explained below.

In general, the length (L2) of the blade can be between 150 and 1,800 millimeters, while the sheath has a damping surface greater than 170 mm ² .

The viscous material can have a viscosity at 40 degrees celcius of between 20 and 1500 poises. Advantageously, the viscosity is around 400 poises. The material is mineral or organic grease.

FIG. 16 illustrates another variant according to which the sheath (145e) covers the bending blade (13) over its entire length.

Note that the distance (D) is considered to be the distance between points A and B which are respectively the midpoints of the area retained by the sheath and the area attached to the ski.

FIG. 17 illustrates a detailed example of a particular embodiment in which the flexion blade (13) slides in the housing (144) of the sleeve (145). The pressure exerted by the viscous film on the blade can be adjusted by means of a pressure member (16) comprising a pad (16a) having a contact surface with the film, a helical spring (16b) which acts directly on the pad in exerting a compressive force and an adjusting screw (16c). By increasing the pressure exerted, this increases the damping value of the ski. The sheath (145) is sealed between the blade and the housing (144) by one or more O-ring (17a, 17b) made of elastomer or by a seal of mastic for example. Of course, provision can be made for the pressure member to also be made watertight at the level of the pad (16a) by a seal to prevent any exit of the viscous material from the housing (144).

FIG. 18 illustrates a second particular embodiment of the pressure member (16) which is of the pneumatic or hydraulic type. It includes a pad (16a) cooperating with an inflatable bladder (16d) via a valve (16e).

The blade comprises over a part of its length at the level of the housing (144) several grooves or grooves (130a) making it possible to accentuate the phenomena of shearing with the viscous material and thus to increase the damping function of the system.

FIG. 19 illustrates another particular mode in which the stirrup (145) comprises a pressure member (16) consisting of a piece of prestressed rubber. This part comprises over its length several transverse grooves (16th) allowing a homogeneous deformation of the part.

Figure 20 illustrates the part before mounting without prestressing.

In the two previous modes, the stirrup is in the form of a closed housing at the end opposite to the introduction of the blade. However, there must be a minimum space (18) allowing the end of the blade to move without it coming into abutment against the wall of the housing.

Of course, the invention is not limited to the embodiments described and represented by way of examples, but it also includes all the technical equivalents and their combinations within the limits of the claims, for example, it can be provided that the damping device is integrated into the structure of the ski.

Claims (23)

1. Ski equipped with at least one shock absorbing device adapted to absorb the vibrations of a ski, constituted by at least one flexion blade (13, 13a, 13b, 13c, 13d) which comprises a first portion (131, 130) rigidly fixed to the ski, and a second portion (130, 131) longitudinally movably connected by shock absorbing means (14), the shock absorbing means (14) being of the type with viscous friction, constituted by at least one layer of viscous material selected from among the mineral or organic fat, and the second portion (130, 131), upon contact with the shock absorbing means, being slidably movable in a stirrup (145, 145a, 145b, 145c, 145d, 145e) connected to the ski.
2. Ski according to claim 1, characterized in that the second portion (130, 131) is longitudinally spaced from the first portion (131,130) over a distance (D).
3. Ski according to claim 2, characterized in that the stirrup (145, 145a, 145b, 145c, 145d, 145e) is U-shaped, with a sliding housing open downwardly.
4. Ski according to claim 1 or 2, characterized in that the stirrup (145d) comprises peripheral walls: one upper wall (146), one lower wall (147) and two lateral walls (148, 149).
5. Ski according to any of the preceding claims, characterized in that the viscous material has a viscosity at 40° Celsius comprised between 20 and 1500 poise.
6. Ski according to any of the preceding claims, characterized in that the flexion blade (13, 13a, 13b, 13c) is a metallic blade, made of aluminum or steel.
7. Ski according to any of claims 1-5, characterized in that the flexion blade (13, 13a, 13b, 13c) is made of a composite material.
8. Ski according to claim 6 or 7, characterized in that the flexion blade has a width (l) comprised between 10 and 45 millimeters, a thickness (e) comprised between 0.5 and 8 millimeters and a length (L2) comprised between 300 and 1800 millimeters.
9. Ski according to any of the preceding claims, characterized in that the flexion blade (13, 13a, 13b, 13c) is arranged and fixed on the upper surface (10) of the ski.
10. Ski equipped with the device according to any of claims 1-8, characterized in that the flexion blade (13, 13a, 13b, 13c) is arranged in the structure of the ski.
11. Ski according to claim 9 or 10, characterized in that the flexible blade (13) extends at the front of the ski, between the front contact point (11) and the zone (2) for mounting the bindings (3, 4).
12. Ski according to any of claims 9, 10, or 11, characterized in that the flexible blade (13) extends rearwardly until the binding mounting zone.
13. Ski according to claim 11 or 12, characterized in that the front portion (131) of the blade is fixed to the ski, whereas the rear portion (130) slides in the stirrup (145, 145a).
14. Ski according to claim 13, characterized in that the stirrup is fixed on the ski at the front of the binding mounting zone.
15. Ski according to claim 13, characterized in that the stirrup extends in the entire zone (2) for mounting the bindings (3, 4) and serves as a support therefor.
16. Ski according to claim 9 or 10, characterized in that the flexible blade (13) extends at the rear of the ski, between the rear contact point (12) and the zone (2) for mounting the bindings (3, 4).
17. Ski according to claim 9 or 10, characterized in that the flexible blade (13) extends rearwardly until the binding mounting zone.
18. Ski according to claim 9 or 10, characterized in that the front portion (131) of the blade is fixed to the ski, whereas the rear portion (130) slides in the stirrup (145, 145a).
19. Ski according to claim 18, characterized in that the stirrup is fixed on the ski at the front of the binding mounting zone.
20. Ski according to claim 18, characterized in that the stirrup extends in the entire zone (2) for mounting the bindings (3, 4) and serves as a support therefor.
21. Ski according to any of the preceding claims, characterized in that the stirrup comprises a pneumatic, hydraulic or elastic pressure member (16), adjustable or not, that acts on the blade.
22. Shock absorption device adapted to equip a ski, comprising at least one flexion blade (13, 13a, 13b, 13c) and one stirrup (145, 145a, 145b, 145c, 145d, 145e) having a housing (144) in which a portion (130, 131) of the flexion blade slides, and comprising a viscous material selected from among the mineral or organic fat.
23. Shock absorption device according to claim 22, characterized in that it is adapted to equip a ski according to any of claims 1-21.

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