EP0753330B1 - Means for practising cross-country skiing, using skating technique - Google Patents

Abstract

The ski has a raised part (6) on the upper surface of the ski and at the level of its sliding zone (5). The ratio of the width of the sole of the ski at this level to the distance separating its lower surface (4) and the base of the boot on its upper surface (7) is between 0.6 and 1.2. A wedge, which is preferably 10 mm thick, can be fixed to the upper surface of the ski. A layer of visco-elastic material is put between the wedge and the upper surface of the ski.

Description

The invention relates to means for practicing cross-country skiing, more particularly intended for the technique known as "the skater's step".

In a known manner, this technique, better known as the expression in English "skating", consists in evolving by making diverge your skis from the direction of progression, progression proper being provided by the alternative exercise of impulses transverse by the skier on one of his skis.

This technique is broken down for each ski essentially into four successive phases, respectively a first phase where skiing is in external support, followed by a flat gliding phase, followed in turn by a phase of pulses on the internal face of the ski, in particular on the internal edge, and finally by a so-called "flight" phase, during which the ski leaves the snow until the next movement is pressed (first phase). There is in fact a time lag between these phases of a ski compared to the other, the sliding phase of the corresponding one substantially at the impulse phase of the other.

In other words, this technique consists in ensuring the progression not by the exercise of a thrust in the longitudinal direction, but at the contrary by means of successive and alternating transverse supports. he It is therefore advisable to optimize the grip, that is to say the impulse, by making it as effective as possible, therefore ensuring when taking pulse, maximum energy transfer.

In order to reduce the duration of this pulse, and to decrease it effort, so the ski must be able to tilt easily on its edge internal without causing too much energy loss by the skier, nor inherent resistance to friction of the ski on the internal edge by its progression in the tilted position. This tilting of the ski on its edge Internal movement is accomplished by moving the knee inward. It is conditioned by two essential parameters related to skiing, namely the width of the ski and the distance from the point of application of the tilting force, typically formed by the knee, relative to the base of the sole, that is to say with respect to the sliding face of the ski sole. In other words, these two parameters can be summed up in the way following: the width of the ski sole and the distance between the base of this sole and the base of support of the skier's shoe on the ski, these two parameters being measured at the level of the ski skid.

According to a simplified and static diagram, this tilting of the ski by relation to the internal edge is analyzed as a rotational movement by relative to an axis formed by this edge, and the energy required to perform this tilting amounts to calculating the moment of the force at the origin of rotation relative to this axis of articulation. The defining characteristics the value of this moment consist of the intensity of the force on the one hand, and by the distance from the point of application of this force relative to the axis of articulation on the other hand, the term distance in front be heard in its geometric sense. In fact, as soon as we wishes to reduce the intensity of the force to be exerted to tip the ski, a solution may consist in increasing this distance from the point of application.

On the other hand, increasing this distance amounts to increasing the duration of support, that is to say, the duration necessary for the tilting of the ski. The invention therefore aims to reduce the energy required to set up works this tilting around the internal edge, in order to be able allow this support, while maintaining a duration of acceptable tilting.

The invention therefore relates to a means for achieving the better compromise between the energy required for tilting and the duration of it.

It therefore relates to means for practicing cross-country skiing according to the "no skater" technique, these means comprising at least two skis each fitted with a binding allowing the front to be secured from the skier's shoe to the ski, said means having at the level of the thickest area of the skis, and typically at the level of the skate, a thickness such that the ratio of the width of the sole of the skis to skate level over the distance between the sliding surface and the sole of the skis from the base of the boot to the surface upper of the skis or on the plate for fixing said boot to the ski is between 0.6 and 1.2.

In other words, the invention consists in increasing the height between the sole of the ski and the boot, and more precisely of the base support of the boot on the binding of the ski.

In this way, by increasing the distance separating the foot from the base of the sole or the extension of the foot, i.e. knee from the base of the sole, the force required to tilting of the ski. Indeed, this energy is directly dependent on the angle defined by the intersection of the right joining the knee to the edge internal ski and plane rotation integrating the side face or edge said ski. In this way, the further the knee is moved away from the base of the sole, and starting from the edge, the more this angle decreases, and in fact the more the force is reduced necessary for tilting with respect to said edge.

Within the meaning of the invention, the fundamental characteristic means for a complete ski, that is to say, provided with its binding if necessary, WHEREAS the defined report takes into account the support base of the shoe. This support base is itself well defined, and corresponds to the sole surface of the shoe actually resting on the ski, or on the plate of the binding, or on any added element or integrated on or in the ski, during the impulse phase.

• amortissement, c'est-à-dire filtration des vibrations du ski, vibrations provenant notamment de la vitesse du ski alpin, sans commune mesure avec la vitesse du ski de fond ;
• débridage du ski, compte tenu de l'effet de serrage inhérent aux fixations avant et arrière en opposition par rapport à la semelle de la chaussure ; cet effet de serrage ne se retrouve en aucun cas dans le domaine du ski de fond, attendu que la chaussure n'est fixée au ski que par son extrémité antérieure, le talon étant en effet libre de se déplacer au moins verticalement ;
• limitation voire suppression des risques de ripage de la chaussure compte tenu de la largeur de la chaussure.

The principle of raising or increasing the thickness of a ski is well known in the field of alpine skis. However, in this particular context, this elevation aims at goals that are completely different from those in the cross-country ski area. These goals can be quickly summarized:

• damping, that is to say filtration of the vibrations of the ski, vibrations originating in particular from the speed of the alpine ski, without common measure with the speed of the cross-country ski;
• unlocking of the ski, taking into account the tightening effect inherent in the front and rear bindings in opposition with respect to the sole of the boot; this tightening effect is not found in any case in the field of cross-country skiing, since the boot is only fixed to the ski by its anterior end, the heel being indeed free to move at least vertically;
• limitation or elimination of the risk of the shoe slipping taking into account the width of the shoe.

In other words, the known elevations in the ski area in no case have the same or similar purpose as that of cross-country skiing, since in particular, the principle of progression put in work is totally different.

Advantageously, the height defined above, that is to say the distance between the sliding surface of the sole of the ski and the base support of the boot on the upper surface of the ski, or on the plate of the binding or on any raised element attached to the ski, is at least equal to 40 mm and at most equal to 60 mm.

According to a first embodiment of the invention, this height can be obtained by fitting a shim added to the upper surface of the ski, on which the binding is placed allowing the binding of the boot to the ski, possibly with its own fixing plate or plate.

In this case, the shims thus added have a thickness comprised between 5 and 30 mm, and advantageously close to 10 mm.

In another embodiment, this wedge is integrated into the internal structure of the ski.

According to a variant of the invention, said wedge is inclined in direction of the front end of the ski, the area at the heel constituting the highest point.

Finally, according to another embodiment of the invention, we interlayer between the cleat and the upper surface of the ski at the level of the skate, a layer of a visco-elastic element, in order to increase the comfort of the skier.

In another variant of the invention, the wedge is integrated into the level of the mounting plate. In this case, the height of the plate is between 10 and 30 mm.

La figure 1 est une représentation schématique en section longitudinale d'un ski de fond conforme à une première forme de réalisation de l'invention.

La figure 2 est une représentation analogue à la figure 1 d'une autre forme de réalisation de l'invention.

La figure 3 est une représentation schématique en section transversale du ski selon la ligne III - III de la figure 2.

La figure 4 est une autre forme de réalisation de l'invention.

The manner in which the invention can be implemented and the advantages which ensue therefrom will emerge more clearly from the following exemplary embodiments, given by way of indication but not limiting in support of the appended figures.

Figure 1 is a schematic representation in longitudinal section of a cross-country ski according to a first embodiment of the invention.

Figure 2 is a representation similar to Figure 1 of another embodiment of the invention.

FIG. 3 is a diagrammatic representation in cross section of the ski along line III - III of FIG. 2.

Figure 4 is another embodiment of the invention.

Figure 1 therefore schematically shows a cross-country ski represented in section longitudinal. This ski (1) has, in known manner, two ends, respectively the heel (2) and the spatula (3), and also includes a gliding sole (4) extending over the entire length of the ski.

Traditionally, the skate area corresponding to a substantially central area, is the thickest area of the ski. This zone of the shoe (5) receives the fixing, allowing the front of the ski boot. According to a characteristic of the invention, this area of the skate has an elevation (6) which, in this case, is integrated in the internal structure of the ski. In other words, the upper face (7) of the ski does not present any discontinuity of nature, i.e. the layer upper, most often decorated, is continuous and envelops the outgrowth constituted by this elevation.

The thickness at the level of the pad reaches, taking into account this elevation (6), a height D of 45 mm, said height being measured from the sliding face of the sole (4) to the bearing face (6) of the boot, that is to say facing the level of which it is fixed on the binding and on which comes to rest the foot of the skier in the impulse phase.

Typically, the ski has a width L at the level of the skate of 45 mm, so that the ratio: width height = 1

We could realize that this elevation favored particularly the pivoting of the ski on its internal edge, allowing optimize the skier's impulse.

In another embodiment shown in FIG. 2, the ski itself is a traditional cross-country ski, the thickness d of which at the level of the skate is typically 35 mm and its width L of 45 mm. This ski receives a wedge (8) attached to the upper face (7) of the ski by any means, in particular by bonding. Advantageously, between the upper face (7) and the shim (8), is inserted a sheet of visco-elastic material (9) intended to dampen vibrations, and more generally, to increase the comfort of use of the skier.

The wedge typically has a thickness e of 10 mm, so that a ratio f is obtained with a standard thickness f of 3 mm of the plate (15): L D = width height = 0.94

There is shown in Figure 3 a cross section of the ski of Figure 2, made at the level of the skate. The reference G ₁ schematically represents the knee of the user on a traditional ski, and it can be observed in fact that the positioning of the wedge (8) allows the knee to be moved away in a position G ₂ from the gliding sole (4), and thereby decreasing the angle α ₂ <α ₁ defined by the intersection of the straight line joining points G ₂ and G ₁ of one of the edges (11, 12) of the sole respectively sliding of the ski, and of the plane integrating the side edges (13, 14) of said ski.

In an advantageous version of this embodiment, shown in Figure 4, the wedge (8) is higher at the heel (10), that is to say at the point of support of the skier's heel, and therefore has a certain downward inclination towards the front of the ski. In this way, we induce the displacement of the center of gravity of the skier upstream, typically in front of the binding, favoring the practice of the so-called "skater's step" technique.

In a variant of the last two embodiments, the wedge (8), provided with the fixing, can be joined reversibly to the surface upper of the ski, so that it is possible to select the type of cleat desired, especially in terms of thickness, profile, or rigidity, in depending on the type of snow encountered.

Furthermore, still in the context of the present invention, the increase in height separating the gliding sole from the base support of the skier's shoe, can be obtained by providing the fixing of a relatively thick plate, suitable for replace the role of the shim (8), or achieve this result in combination with a thinner shim.

The skis according to the invention therefore favor pivoting relative to at their internal edge, reducing the time required for this pivoting or tilting, and hence, optimizing the setting phase impulse, fundamental during progression according to the so-called technique of the skater's step.

Claims (10)

1. Means for practicing cross-country skiing, more particularly using the "skating" technique, comprising at least two skis, each fitted with a binding making it possible to secure the front of the skier's boot to the ski, which means have, level with the thickest region of the skis and typically level with the support region (5), a thickness such that the ratio of the length L of the sole of the skis at this level to the distance D separating the gliding surface of the sole (4) of the skis from the base where the boot bears on the upper surface (7) of the ski or on the plate of the binding for securing said boot to the ski is between 0.6 and 1.2.
2. The means for practicing cross-country skiing as claimed in claim 1, wherein the distance D separating the gliding surface of the sole (4) of the ski from the base where the boot bears on the upper surface (7) of the ski or on the plate of the binding for securing said boot to the ski is at least equal to 40 mm and at most equal to 60 mm.
3. The means for practicing cross-country skiing as claimed in one of claims 1 and 2, wherein the skis comprise on their upper surface (7), level with the support region (5), an attached wedge (8) on which the binding allowing the front of the boot to be secured to the ski is fitted.
4. The means for practicing cross-country skiing as claimed in claim 3, wherein, level with the support region (5), a layer of a viscoelastic element (9) is interposed between the attached wedge (8) and the upper surface (7) of the ski.
5. The means for practicing cross-country skiing as claimed in one of claims 3 and 4, wherein the thickness e of the wedge (8) is between five and thirty mm, and advantageously close to ten mm.
6. The means for practicing cross-country skiing as claimed in one of claims 3 to 5, wherein the wedge (8), fitted with the binding, is reversibly securable to the upper surface (7) of the ski.
7. The means for practicing cross-country skiing as claimed in one of claims 3 to 6, wherein the wedge (8) is integrated level with the plate (15) of the binding allowing the front of the boot to be secured to the ski.
8. The means for practicing cross-country skiing as claimed in claim 7, wherein the thickness of the plate (15) is between ten and thirty millimeters.
9. The means for practicing cross-country skiing as claimed in one of claims 1 and 2, wherein the skis comprise a wedge (6) integrated with their internal structure, the upper surface (7) of the skis enclosing this protuberance.
10. The means for practicing cross-country skiing as claimed in one of claims 3 to 6, wherein the wedge (6, 8) is higher level with the heel (10), that is to say level with the point where the skier's heel bears.

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