EP0420774B1 - Ski, method of manufacture of the ski and apparatus for implementation - Google Patents

Abstract

This snow ski, the sides of which have an inclination which is variable in relation to the plane of the sole of the ski, at different points along its length, and are constituted by curved convex or concave lines, in which the profiles of the sides are of variable curvature according to the cross-section in question of the ski. A procedure for manufacturing this ski consists, starting from a rough ski, in carrying out the machining of the lateral parts of the ski with the aid of a rotary tool with an axis perpendicular to the plane of the upper surface of the ski, the active surface of which is generated by a continuous monotonic curve, by carrying out a relative movement of the tool and of the ski simultaneously, in the direction of the length of the ski, in the direction of the width of the ski and in a direction perpendicular to the plane of the upper surface of the ski.

Description

The present invention relates to a snow ski, a process for its manufacture, and a device for the implementation of this process.

Most often, a ski has a rectangular section, the lower face of which is delimited by the sliding sole, the upper face of which is delimited by a screen-printed covering wall, and the two lateral edges of which are delimited by edges. At the junction line, between the sole and the edges, metal edges are provided to improve the guiding conditions and the grip on hard snow and on ice.

It is also known to make skis whose edges are not perpendicular to the lower face and to the upper face, but inclined so as to form, over at least part of the length of the ski, an acute angle with the lower sole. . This angle may have, at the ends of the ski - tip and heel - a value less than that which is found at the level of the skate. Such an arrangement makes it easier to ski in powder snow, since the ends of the ski "cut" the snow better than in the case of a ski of rectangular section over its entire length.

Generally, skis with inclined edges have, when viewed in cross section, inclined rectilinear parts, possibly concave or convex, at the edges.

Document FR-A-2 522 976 relates to a ski comprising chants of variable inclinations, of concave or convex surfaces.

Document US-A-3,916,965 relates to a woodworking machine of the "router" type, in which the workpiece is movable longitudinally, and the tool is movable in the direction of the width of this piece.

The document FR-A-2 181 061 relates to a process for manufacturing curved articles, such as skis, consisting in placing pre-glued elements in an elastic mold, then in subjecting the mold to a pressure with simultaneous heating.

The present invention, defined according to the terms of claim 1, aims to provide a ski with inclined edges, where the profiles of the inclined areas of the edges constituted by curved, convex or concave lines have a variable curvature along the ski.

Such a structure makes it possible to influence the mechanical characteristics of the ski, its aesthetics and the resistance to wear of the upper edges.

However, skis with inclined edges present production difficulties. A ski with inclined edges can be obtained directly by molding in a shaped mold. In such a case, it is necessary to have an expensive tool, and difficult to implement for certain structures.

It is also conceivable to produce a ski with inclined edges, by machining the edges using a numerically controlled machine tool. However, to produce particular shapes, and in particular curved surfaces, it is necessary to have a machine with four axes, with cylindrical cutter, which requires a very heavy investment. It would also be possible to perform machining using a three-axis machine tool, with a milled cutter.

The present invention aims to remedy these drawbacks by providing a method and a device making it possible to obtain, by machining, a snow ski whose edges have a variable inclination relative to the plane of the ski sole, at different points of its length, and are formed by curved lines, convex or concave, the profiles of the edges having a variable curvature according to the considered section of the ski.

To this end, the process for manufacturing a ski which it relates to consists, as defined in claim 2, starting from a ski blank, in carrying out the machining of the lateral parts of the ski using at least one rotary tool with an axis perpendicular to the plane of the upper face of the ski, the active face of which is generated by a continuous monotonous curve and of variable curvature, by performing a relative movement of the tool and the ski simultaneously, in the direction of the length of the ski, in the direction of the width of the ski, and in a direction perpendicular to the plane of the upper face of the ski.

The adjustment of the depth of pass in the direction of the width of the ski makes it possible to give it the desired profile. Depending on the position of the tool with respect to the length of the ski, this depth of pass varies.

The relative movement of the tool and the ski, perpendicular to the plane of the upper face of the latter, makes it possible to vary the inclination of the edges and the radius of curvature thereof. Indeed, depending on the position of the edge of the ski, relative to the active part of the tool, the machining is produced at a greater or lesser angle, relative to the plane of the sole and to the plane of the upper face of the ski.

It is therefore a simple method, allowing a variable inclination of the edges along the length of the ski.

It should be noted that the curvature of the edge is variable along the ski, insofar as the generator of the surface of revolution of the tool, is itself produced from several sections of successive curves, plotted from mathematical formulas different from each other.

According to a simple embodiment, this method consists in achieving a relative movement of the ski and the tool, in the direction of the length of the ski, by displacement of the ski longitudinally with the tool, a relative movement in the direction of the width of the ski, by displacement of the tool relative to the ski, and a relative movement in a direction perpendicular to the plane of the ski, by deformation of the ski by bending, during the machining operation.

• un berceau en creux comportant des moyens de bridage d'une ébauche de ski en position cintrée dans une direction perpendiculaire à sa face supérieure,
• des moyens de déplacement longitudinal de l'ensemble constitué par le berceau et l'ébauche du ski, et
• au moins un outil tournant dont la face active est engendrée par une courbe continue monotone et de courbure variable, d'axe perpendiculaire au plan de la face supérieure du ski, et déplaçable dans la direction de la largeur du ski.

A device for implementing this method comprises:

• a hollow cradle comprising means for clamping a ski blank in the bent position in a direction perpendicular to its upper face,
• means for longitudinal displacement of the assembly constituted by the cradle and the draft of the ski, and
• at least one rotary tool whose active face is generated by a continuous monotonous curve and of variable curvature, of axis perpendicular to the plane of the upper face of the ski, and movable in the direction of the width of the ski.

In such a case, the variation of the curvature of each edge of the ski over the length thereof is obtained by relative displacement of the inclined edge of the ski relative to the tool, in a plane perpendicular to the plane of the upper face of the ski, resulting from the shaping of the ski in its cradle.

• Figure 1 est une vue de dessus d'un ski conforme à l'invention,
• Figures 2 et 3 en sont deux vues en coupe transversale, et à échelle agrandie, selon les lignes II-II et III-III de figure 1,
• Figure 4 est une vue en perspective, d'un outil d'usinage de ce ski,
• Figures 5 à 7 sont trois vues de côté, représentant l'outil et le ski, au cours de trois phases d'usinage, respectivement à l'avant du ski, dans la zone de patin de celui-ci et à proximité de son talon,
• Figure 8 est une vue très schématique de côté, des moyens permettant l'usinage du ski,
• Figure 9 est une vue de dessus, d'un ski en cours d'usinage.

Anyway, the invention will be better understood with the aid of the description which follows, with reference to the appended schematic drawing representing, by way of nonlimiting example, an embodiment of this ski, as well as a form execution of means for obtaining the inclined edges thereof:

• FIG. 1 is a top view of a ski according to the invention,
• Figures 2 and 3 are two views in cross section, and enlarged scale, along lines II-II and III-III of Figure 1,
• FIG. 4 is a perspective view of a tool for machining this ski,
• Figures 5 to 7 are three side views, representing the tool and the ski, during three machining phases, respectively at the front of the ski, in the skate area thereof and near its heel ,
• FIG. 8 is a very schematic side view of the means allowing the machining of the ski,
• Figure 9 is a top view of a ski during machining.

The ski shown in FIG. 1 is an alpine ski, having a tip 2, a shoe 3, and a heel area 4. On the upper face of the ski, there are mounted, in the central part thereof, bindings 5 , for a ski boot. The ski, according to the invention, comprises edges, that is to say lateral faces connecting the upper face 6 and the lower face 7, which are not perpendicular to these two faces as is usually the case, but which are inclined, this inclination being variable along the ski. Thus, in the skate area, each edge 8a forms, as shown in FIG. 2, an angle A of less than 90 ° with the sole 7, while near the tip 2 and the heel 4, each edge 8b forms, as shown in FIG. 3, an angle B with the sole 7, the value of the angle B being less than that of the angle A. As can also be seen from the drawings, the edges 8 are not formed by flat surfaces , but have, seen in cross section, a curved profile, in this case convex, corresponding to radii of curvature respectively R1 in the skid area and R2 in the tip and heel areas.

The ski, according to the invention, is obtained from a blank of substantially rectangular section, that is to say of which the edges are substantially perpendicular to the upper face 6 and to the lower face 7. The ski itself even is achieved by machining the blank, using a tool which is shown in more detail in Figure 4. This tool comprises a shaft 9, at the end of which is mounted an active part 10, having a surface of concave revolution 12, this surface of revolution being generated by a generator which is itself concave, which is constituted by a complex curve, the curvature of which is variable.

• un déplacement longitudinal du ski par rapport à chaque outil,
• un déplacement latéral de chaque outil par rapport au ski,
• un déplacement relatif de chaque outil et du plan supérieur du ski, perpendiculairement au plan du ski.

According to the essential characteristic of the method according to the invention, the variation in the inclination of the edges of the ski is obtained by carrying out relative displacements of each tool and of the ski:

• a longitudinal displacement of the ski relative to each tool,
• lateral movement of each tool relative to the ski,
• a relative displacement of each tool and of the upper plane of the ski, perpendicular to the plane of the ski.

Figures 5 to 7 show three positions of the ski relative to the tool, respectively in an area close to the tip, in the skate area, and near the heel.

As can be seen from the drawings, the distance between the underside of the ski and the base of the tool has relatively large values H1 and H3 in the areas close to the tip and the heel. As a result, the ski is in contact with the upper part of the active face of the tool, that is to say the part of the active face which is relatively slightly inclined relative to the horizontal.

On the contrary, in the skid area, as shown in FIG. 6, the underside of the ski is at a relatively short distance H2 from the base of the tool, so that the edge of the blank is in contact with a part of the active surface of the tool relatively close to the vertical.

It is also possible to play on the depth of the pass, by adapting the transverse movement of the tool relative to the ski. Given the shape of the ski, the distance d2 between the median longitudinal axis of the ski and the axis of the tool is less in the shoe zone, as shown in FIG. 6, at the corresponding distances d1 and d3, figures 5 and 7, in the areas of the tip and the heel.

Figures 8 and 9 show means for the implementation of this method.

FIG. 8 more specifically shows a cradle 15, hollow, in which a ski is held pressed in by clamping by support pads 16. It follows from this structure that, taking into account the hanger which is given to the ski, it occurs , during the longitudinal displacement of the cradle, a relative displacement in the height direction, of each tool and of the upper plane of the ski.

FIG. 9 shows a ski in top view, during machining, the transverse displacement of each tool being produced by means of a guide roller 17 mounted on the axis of the tool, bearing on a template 18, the copying of which makes it possible to obtain, above the edges, the profile of the lateral parts of the ski.

As is apparent from the above, the invention provides a great improvement to the existing technique, by providing a ski of interesting structure, obtained by a simple and inexpensive method and device of implementation.

It is possible to work using current equipment, namely a router with one or two machining heads, and a jig with two functions, or two independent jigs, to respectively bring the ski into position by relative to the height of the tool, and the copying of the profile of the lateral parts of the ski.

It goes without saying that the invention is not limited to the sole embodiment of this ski, described above by way of example, nor to the sole mode of implementation of its manufacturing process. Thus, in particular, the inclined surfaces could be not convex, but concave, that the tools arranged on either side of the ski could have a different profile in order to obtain a ski with an asymmetrical profile, or even that the ski could be fixed and each tool displaceable longitudinally, without thereby departing from the scope of the invention.

Claims (5)

1. Snow ski on which the edges (8a, 8b) have a slope which is variable with respect to the plane of the base of the ski, at different points over its length, and are formed by curved convex or concave lines, characterised in that the profiles of the edges have a variable curvature according to the particular section of the ski.
2. Method of manufacturing a ski according to Claim 1, characterised in that it consists, starting from a ski blank, of machining the lateral parts of the ski by means of at least one rotary tool (10) with an axis perpendicular to the plane of the top face of the ski, the active face (12) of which is generated by a continuous monotonic curve with a variable curvature, and effecting a relative movement of the tool and ski simultaneously, in the direction of the length of the ski, in the direction of the width of the ski, and in a direction perpendicular to the plane of the top face of the ski.
3. Method according to Claim 2, characterised in that it consists of effecting a relative movement of the ski (3) and tool (10), in the direction of the length of the ski, by moving the ski (3) longitudinally to the tool (10), a relative movement in the direction of the width of the ski, by moving the tool with respect to the ski, and a relative movement in a direction perpendicular to the plane of the ski, by deformation of the ski by means of flexion, during the machining operation.
4. Device for implementing the method according to either one of Claims 2 or 3, characterised in that it comprises:

   - a hollow cradle (15) incorporating means for clamping (16) a ski blank in position curved in a direction perpendicular to its top face,

   - means for moving longitudinally the assembly consisting of the cradle and ski blank, and

   - at least one rotary tool (10), the active face (12) of which is generated by a continuous monotonic curve with a variable curvature, with an axis perpendicular to the plane of the top face of the ski, and movable in the direction of the width of the ski.
5. Device according to Claim 4, characterised in that the transverse movement of each tool (10) is achieved by a guide roller (17) mounted on the tool shaft bearing against a template (18) secured to the cradle (15).

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