ALPINE SKI WITH CONTROLLED FLEXION

Abstract

An alpine ski includes a zone for mounting a binding centered on a mounting point, and a single particular flexion deformation zone arranged between the mounting zone and one or each end of the ski. Under a static load of 900 Newtons, applied to the center of the particular deformation zone and along a direction perpendicular to the ski sole, the deformation zone adopts a generally dihedral configuration, whose deflection is greater than or equal to 13 mm, 15 mm in a particular embodiment, the ski being supported on two rods arranged under the sole, symmetrically on both sides of the zone and spaced from one another by an axial distance equal to 400 mm.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority under 35 U.S.C. §119 of French Patent Application No. 08 06872, filed on Dec. 8, 2008, the disclosure of which is hereby incorporated by reference thereto in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to an alpine ski used, in particular, for the practice of “freestyle” skiing, i.e., for performing various maneuvers, or tricks, such as jumps or glides in an adapted environment which includes rails, for example, on which a skier can slide his/her skis transverse to the longitudinal axis thereof.

2. Description of Background and Other Information

It is known from U.S. Pat. No. 7,341,271 to configure a ski to have zones with variable flexional rigidity in order to obtain an efficient transmission of forces when the ski adopts a curved configuration, with a substantially constant radius of curvature over its length, as shown in the drawings of this patent.

The document FR 2 042 420 also discloses a ski having a zone with a reduced flexional strength. In this case, the objective is to make it easier to ski using a lateral inclination technique, which requires occupying a rear position. As described in the preamble of the document FR 2 042 420, a rotation occurs between the front portion and the rear portion of the ski, around a point located immediately behind the middle of ski, i.e., in the area of the rear binding, or heel piece.

For the practice of freestyle, a skier sometimes wants to perform a trick in which the skier slides the front or rear end, i.e., the shovel or spatula, of the skis on a rail. In this case, the skis of the prior art flex evenly over their entire lengths, so that it is difficult for a skier to reproduce the same maneuver several times. Indeed, depending upon the positioning of the ski with respect to the rail, it is not possible to anticipate the behavior of the ski with a sufficient degree of accuracy.

SUMMARY

The invention improves upon characteristics and abilities of known skis, overcoming, or at least lessening, the aforementioned disadvantages and, more particularly, the invention encompasses an alpine ski that facilitates the performance of certain freestyle maneuvers, or tricks, and that facilitates the reproducibility of such freestyle maneuvers/tricks.

To this end, the invention is directed to an alpine ski having binding mounting zone centered on a mounting point, and a unique zone of deformation in flexion between the mounting zone and at least one end of the ski.

In the context of the Invention, a deformation in flexion of the ski is a flexion deformation along a longitudinal axis or direction of the ski.

According to the invention, the particular flexion deformation zone, the location of which is known to the skier, makes it possible to obtain a localized and reproducible deformation of the ski in that zone. The front end, or spatula or shovel, sometimes simply referred to as the tip, defined between this zone and the extreme end of the ski, on the one hand, and the zone for mounting the binding, on the other hand, practically does not flex. Thus, depending upon the characteristics of the particular deformation zone, the skier can obtain the same behavior several successive times, in particular while performing maneuvers, or tricks, known as a “nose press” or “tail press”.

According to advantageous, but non-limiting aspects of the invention, such a ski can incorporate one or several of the following characteristics, taken in any technically acceptable combination:

• • The particular flexion deformation zone is arranged so that, under a static load of 900 Newtons (N) applied to the center of the particular deformation zone and along a direction perpendicular to the sole of the ski, this deformation zone adopts a generally dihedral configuration whose deflection is greater than or equal to 13 mm, and 15 mm in a particular embodiment, the ski being supported on two rods (202, 204) arranged under the sole (10), symmetrically on both sides of the zone (Z₁) and spaced from one another by an axial distance d₂₀₀ equal to 400 mm;
  • The particular deformation zone extends, with respect to the mounting point of the ski, along an axial distance ranging between 285 and 365 mm. In the context of the present invention, an axial distance is measured parallel to a longitudinal axis of the ski;
  • The particular deformation zone is centered on a softening point arranged, with respect to the mounting point, at a distance ranging between 360 and 480 mm;
  • The particular deformation zone is a zone of reduced thickness, or height, in relation to the mounting zone, on the one hand, and to the shovel (or spatula) defined between the particular deformation zone and the adjacent end (or tip) of the ski, on the other hand. In this case, the particular deformation zone has a minimal thickness ranging between 6 and 8 mm, whereas the shovel has a minimal thickness ranging between 8.5 and 11 mm;
  • In an alternative, the particular deformation zone is formed by a fitting made of a more flexible material than the constituent material(s) of the mounting zone and of the end sections of the ski.
    • The preferred deformation zone is equipped with means for limiting or controlling its deformation. These means can include a deformable plate fixed on the upper surface of the ski, and which is mechanically biased as a function of the deformation of the ski in the particular deformation zone;
    • The ski includes two particular deformation zones arranged between the mounting zone and the front tip of the ski, and between the mounting zone and the rear tip of the ski, respectively.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood, and other advantages thereof will become more clearly apparent, from the following description of seven embodiments of an alpine ski, given only by way example, and in reference to the annexed drawings, in which:

FIG. 1 is a perspective view of a ski according to a first embodiment of the invention;

FIG. 2 is a top view of the ski of FIG. 1;

FIG. 3 is a side view of the ski of FIGS. 1 and 2;

FIG. 4 is a longitudinal cross section, on a larger scale, of the detail IV in FIG. 3;

FIG. 5 is a partial side view of the ski of FIGS. 1 to 4, in a configuration for testing of its flexibility, and on a smaller scale than FIG. 4;

FIG. 6 is a side view corresponding to the detail IV in FIG. 3, for a ski according to a second embodiment of the invention;

FIG. 7 is a view similar to FIG. 6, for a ski according to a third embodiment of the invention;

FIG. 8 is a view similar to FIG. 6, for a ski according to a fourth embodiment of the invention;

FIG. 9 is a view similar to FIG. 6, for a ski according to a fifth embodiment of the invention;

FIG. 10 is a view similar to FIG. 6, but with a partial cut-away zone, for a ski according to a sixth embodiment of the invention; and

FIG. 11 is a partial side view of a ski according to a seventh embodiment of the invention.

DETAILED DESCRIPTION

The ski 1 shown in FIGS. 1 to 5 is a ski known as freestyle ski, the central longitudinal axis X₁ of which extends from its front end 2 towards its rear end 4, these two ends, or twin tips, being raised with respect to a mounting zone 6 for a binding for a boot 130 shown in FIG. 3. This mounting zone is defined in accordance with the NF ISO 8364 standard. The front end 2, or front tip, is located on the side of the mounting zone 6 on which the front abutment 110 of the binding is fixed; whereas the rear end 4, or rear tip, is arranged on the side of the zone 6 where the heelpiece 120 of the binding is mounted. Although a twin tip ski is illustrated in the exemplary embodiment shown in FIG. 1, the invention encompasses other forms of alpine skis, including those having a front tip and a rear tail, the latter not being raised upwardly like the front tip.

The waist width I₁ of the ski 1 is greater than 66 mm, or greater than 75 mm in a particular embodiment. The zone 6 is centered on a mounting point A₆ defined according to the NF ISO 8364 standard. The mounting zone has an axial length L₆.

A length or a dimension is referred to as “axial” when it extends parallel to the axis X₁, whereas it is referred to as “transverse” when it extends perpendicular to this axis. The waist width I₁ is a transverse width.

The zone 6 has a minimal thickness e₆ ranging between 8 and 25 mm over its length L₆. The thickness of the ski in the zone 6 is, for a desired rigidity, a function of its width in this same zone.

The ski 1 has an upper surface 8 and a sole 10.

A particular deformation zone Z₁ of the ski 1 is arranged between the mounting zone 6 and the front end 2, i.e., forward of the zone 6. A second particular deformation zone Z₂ is arranged between the zone 6 and the rear end 4, i.e., at the rear of the zone 6.

Each of the particular flexion deformation zones Z₁ and Z₂ is manifested by a localized reduction in the thickness of the ski 1.

These zones Z₁ and Z₂ are provided to adopt a generally dihedral configuration when the ski is subjected to a deformation force in flexion. Such is particularly the case when a skier performs a maneuver known as a “nose press”, i.e., with the front section, or shovel or spatula, of the ski supported on a rail, in which case the zone Z₁ becomes deformed. Similarly, the zone Z₂ becomes deformed when the user performs a maneuver known as a “tail press”, i.e., the rear section, or shovel or spatula, of the ski is supported on the rail.

As seen more particularly in FIG. 4, the ski 1 includes, in addition to the sole 10, an upper reinforcement 12, or reinforcement layer, made of glass fibers or other strengthening material, a lower reinforcement 14, or reinforcement layer, also made of glass fibers, e.g., and a core 16 that can be made of wood or foam. In a particular embodiment, the reinforcements 12 and 14 are loaded with metal, such as aluminum, for example. The reinforcements 12 and 14 can also be made of carbon fibers, aramide, Kevlar® (registered trademark), steel, aluminum, titanal, or other metal alloys. These reinforcements can also be comprised of several layers, for example a layer of glass fibers and a layer of aluminum.

A finish layer 15, commonly referred to as the “top”, is affixed on, or above, the reinforcement 12 and bears the decoration of the ski. It can be made of an assembly of a plurality, or several, layers.

The thickness e₁₆ of the core 16 is locally reduced in order to form the zone Z₁, so that the total thickness e₁ of the ski 1 in the zone Z₁ has a minimal value ranging between 6 and 8 mm, i.e., a value substantially less than that of the thickness e₆. The thickness e₁ corresponds to the sum of the minimal thickness e₁₆ and of the thicknesses of the reinforcements 12 and 14 and of the sole 10, these two thicknesses being substantially constant over the length of the ski 1.

In practice, the minimal value the thickness e₁₆ is greater than 1.5 mm to limit the risk of rupture of the core 16 in the zone Z₁. In an alternative, however, one can provide an interruption of the core 16 in the area of the zone Z₁ and/or zone Z₂, which makes it possible to put the upper 12 and lower 14 reinforcements in contact, in order to limit the constraints in these reinforcements.

The front shovel 18, or spatula, of the ski 1 is defined herein as being the portion of the ski extending between the zone Z₁ and the front end 2, or tip. The minimal thickness e₁₈ of the shovel 18 is between 8.5 and 11 mm. This thickness is greater than in conventional skis, in which it has a value generally ranging between 5 and 7.5 mm. This needs to be brought closer because the shovel 18 can be substantially more rigid than in conventional skis, because the flexing of the ski occurs primarily in the area of the zones Z₁ and Z₂.

In practice, the rigidity of the shovel 18 is dependent upon the distance between the reinforcements 12 and 14, i.e., upon the thickness of the core 16. In the case in which the shovel includes a top or layer that is spaced from the upper reinforcement, with a possible interposition of a fitting or spacer, the rigidity of the shovel is not actually affected because the distance between the reinforcements remains similar to that of the illustrated embodiment. For example, the shovel can have a total thickness of 16 mm by having the same rigidity as that of the shovel 18 shown in the drawing figures, if the thickness of the sandwich comprised of the elements 12, 14, and 16 has a minimal value ranging between 8.5 mm and 11 mm.

The rear shovel or spatula 19 of the ski 1 is defined between the zone Z₂ and the rear end 4, or, in the illustrated twin tip ski, the rear tip. The minimal thickness e₁₉ of the shovel 19 has same value as the thickness e₁₈.

A straight line Δ₁, perpendicular to the axis X₁, is positioned where the thickness of the ski begins to decrease by moving away from the point A₆, in relation to the value the thickness e₆. A straight line Δ′₁, perpendicular to the axis X₁, is positioned where the thickness of the ski 1 begins to decrease, by moving away from the end 2, in relation to the value the thickness e₁₆. The zone Z₁ is defined between the straight lines Δ₁ and Δ′₁.

A central point A₁ of the zone Z₁ is equidistant from the straight lines Δ₁ and Δ′₁ and is located on the surface 8, halfway between the right and left lateral edges 20 and 22 of the ski 1. This point can be considered as a softening point, or a weakened point, of the ski in the zone Z₁.

The axial length L₁ of the zone Z₁, i.e., the axial distance between the straight lines Δ₁ and Δ′₁, has a value ranging between 150 and 200 mm. The axial distance D₁ between the straight line Δ₁ and the mounting point A₆ has a value ranging between 285 and 385 mm. The axial distance D′₁ between the points A₁ and A₆ is between 360 and 480 mm.

The zone Z₁ should be sufficiently spaced from the middle of the ski so that the particular deformation zone has a limited effect on the normal performance or functioning of the ski, i.e., such as that while traversing a flat trail, without any particular trick or maneuver being performed by the skier. In practice, as shown in FIG. 3, the zone Z₁ is positioned well beyond the rear binding. Thus, during normal use, the skier's support forces are not modified. Conversely, as soon as the skier takes support on the rear portion of the ski, in order to perform a trick, or maneuver, the particular deformation zone comes into play and precisely determines the location at which the ski indeed will become deformed.

The zone Z₂ is substantially symmetrical with the zone Z_i with respect to the mounting point A₆. It extends between two straight lines Δ₂ and Δ′₂ perpendicular to the axis X₁, and there is a central point A₂, or softening point, of the zone Z₂ on the surface 8. The axial length L₂ of the zone Z₂ is between 150 and 200 mm, and the straight line Δ₂ extends a distance D₂, ranging between 285 and 365 mm with respect to the mounting point A₆. The distance D′₂ between the points A₂ and A₆ is between 360 and 480 mm.

In an alternative embodiment, the zone Z₂ may not be at the same distance from the point A₆ as the zone Z₁. In particular, zones with various lengths can be provided along the axis X₁, between the mounting zone 6 and the zones Z₁ and Z₂.

The lengths L₁ and L₂ are not necessarily equal, just as the lengths D₁ and D₂, on the one hand, and D′₁ and D′₂, on the other hand.

The ski 1 includes a single particular deformation zone Z₁ between the mounting zone 6 and the end 2, so that the ski 1 is capable of becoming deformed in only one zone between the front of the skier's boot and the front end of the ski. Similarly, a single particular deformation zone is provided between the mounting zone 6 and the rear end 4, so that the skier knows that the ski can become deformed in only one zone between the rear of the boot and the rear end of the ski.

In view of the existence of the zones Z₁ and Z₂, and of the relative rigidity of the mounting zone 6 and of the shovels 18 and 19, the flexing behavior of the ski 1 is reproducible, i.e., predictable, which makes it easier for the skier to control the ski, including controlling the ski during the performance of elaborate freestyle tricks.

This behavior can be characterized by a measurement of the flexion properties of the ski 1 when a given force is exerted on the ski, which is supported on two rods 202 and 204, each having a circular cross section, the centers of which are spaced from one another by an axial distance d₂₀₀ equal to 400 mm, and which are arranged under the sole 10 of the ski, symmetrically on both sides of the zone Z₁.

When the ski 1 is supported on the two rods 202 and 204 under the effect of its weight, its sole 10 is substantially flat in the zone Z₁, and its trace in the plane of FIG. 5 is a horizontal straight line Δ₃ which passes on the tops of the bars 202 and 204.

When a load E₁ perpendicular to the sole 10 is exerted in the center of the zone Z₁, i.e., in the vicinity of the point A₁, and in a direction extending from the surface 8 towards the sole 10, while the ski 1 is in support on the rods 202 and 204, as explained hereinabove, the ski flexes in the zone Z₁ and adopts a generally dihedral configuration in the vicinity of this zone, as shown in FIG. 5.

The bending deflection f of the zone Z₁ is shown in the configuration of FIG. 5. This deflection is the maximum distance between the straight line Δ₃ and the sole 10, when the ski 1 is subject to the load E₁.

The thicknesses and distances mentioned hereinabove are such that, for a static load E₁ with an intensity equal to 900 Newtons, i.e., corresponding to a weight of approximately 90 kg, and a distance d₂₀₀ equal to 400 mm, the deflection f is greater than 13 mm.

These thicknesses and distances, for particular embodiments, can be selected by digital simulation or tests on samples, so that this deflection is greater than 15 mm.

The zone Z₂ is also configured so that the deflection defined under the same conditions has a value greater than 13 mm, and 15 mm in a particular embodiment.

This confers a good behavior for the ski 1 when the skier performs tricks, or maneuvers, such as mentioned hereinabove.

Moreover, when the skier skis in powder snow, the flexion zone Z₁ enables the shovel 18 to pivot upwards, about an axis perpendicular to the axis X₁ and passing in the vicinity of the point A₁, which makes it easier for the ski 1 to lift off.

In the second to seventh embodiments shown in FIGS. 6 to 11, the elements that are similar to those of the first embodiment have the same numeral references.

The ski 1 of FIG. 6 includes, above the particular deformation zone Z₁, a metal plate 30 that is secured onto the ski 1 by means of two screws 32. This plate can be secured on the ski 1 by any other appropriately configured attachment expedient. In an alternative, the plate 30 is made of composite material.

An elastomeric block 34 is arranged between the plate 30 and the upper surface 8 of the ski 1. The plate 30 makes it possible to maintain the longitudinal rigidity of the ski, i.e., related to longitudinal flexion, to a value comparable to that of a conventional ski, as long as the plate 30 does not buckle. In other words, the ski becomes slightly deformed or does not become deformed in the zone Z₁ as long as the bending stress is not sufficient to cause the plate 30 to buckle. With respect to the embodiment of FIGS. 1 to 5, the ski has a behavior such that a threshold value of the bending stress makes it possible to achieve an effective flexing in the zone Z₁.

The elastomeric block 34 guarantees that if the plate 30 buckles, it becomes deformed upwards and not in the direction of the sole 10 of the ski 1. This block is however optional insofar as a preferred buckling direction for the plate 30 can be obtained by means of an adapted configuration thereof.

In this embodiment, the shovel 18 is not thicker than in a conventional ski. It has a thickness e₁₈ ranging between 5 mm and 7.5 mm. Indeed, one can consider that the plate 30 at least partially compensates for the loss of rigidity of the ski, whereas, in the first embodiment, it is the thick shovels that fulfill this function.

In the embodiment of FIG. 7, a counter-deflection stop blade or plate 40 is secured on the ski by a screw 42 arranged in the area of one of its ends 43. The blade 40 extends above the particular deformation zone Z₁ of the ski 1. In the area of its end 44 opposite the screw 42, the blade 40 is bent so as to come in support against an abutment 46 that is fixed with respect to the ski 1. Thus, in the case of a load that tends to deform the shovel 18 in the direction of the arrow F₂ in FIG. 7, the blade 40 comes in support via its end 44 against the abutment 46, which limits the deformation of the ski 1.

To make the ski more lively, i.e., to provide the ski with more reactivity or with pep, a spring 48 is inserted between the end 44 of the blade 40 and an abutment 49 fixed with respect to the ski 1. This spring exerts on the end 44 a force E₂ that is directed towards the screw 42, which can enable the blade 44 to restore the energy of the spring after bending, and to provide more rebound to the ski.

In the embodiment of FIG. 8, two abutments 50 and 60 are attached in the particular bending zone Z₁, and they each have a surface 52 or 62 adapted to come in support against the surface of the other abutment, so as to limit the flexing of the ski 1 in the zone Z₁. These abutments thus make it possible to limit the deformation of the ski 1 to a predetermined angle corresponding to the angle defined between the surfaces 52 and 62.

According to one advantageous aspect of a particular embodiment of the invention, an elastomeric wedge or spacer can be positioned between the surfaces 52 and 62, which improves the bending progressiveness in the zone Z₁ and which yields better performance when the ski snaps back.

In the embodiment of FIG. 9, the particular deformation zone Z₁ of the ski 1 is formed by a succession of elastomeric blades 70 inserted in the ski 1, starting from its upper surface 8, and which are adapted to be compressed to enable the ski to bend.

The lengths of the blades 70, taken parallel to the thickness e₁ of the ski 1, increases and then decreases over the length of the zone Z₁ taken parallel to the axis X₁. In an alternative, all of the blades 70 can have the same length.

In the embodiment of FIG. 10, an elastomeric block 80 is positioned in the thickness of the ski 1, which creates a particular deformation zone Z₁, this zone being covered with a counter-deflection stop blade 90 functioning similar to the blade 40 in the embodiment of FIG. 7. The abutment 46 is replaced by one or several screws 96 fixed in the ski 1, and against which the ends with oblong openings 94 provided in the blade 90 can come into support.

In the embodiment of FIG. 11, an elastomeric block 100 extends on both sides of a small island 102 forming the upper portion of the mounting zone 6 of the ski 1. The elastomeric block has a minimal thickness e₁₀₀ under the small island 102, this thickness increasing at the front and rear of the small island 102 to create two particular deformation zones Z₁ and Z₂ of the ski 1.

An upper reinforcement 104, visible through a cut-away section of FIG. 11, extends on the tops of the shovels 18 and 19 of the ski 1, and also under the block 100 and the small island 102, in order to guarantee a certain rigidity of the ski 1.

The deformation zones Z₁ and Z₂ of the skis of the embodiments of FIGS. 6 to 11 generally have the same behavior as those of the first embodiment: under a static load of 900 Newtons, applied to the center of each of these deformation zones along a direction perpendicular to the ski sole. Each deformation zone adopts a generally dihedral configuration, with a deflection f that has a value greater than or equal to 13 mm, and 15 mm in a particular embodiment, when the ski is supported on two rods or beams that are 400 mm apart.

The technical features of the various embodiments mentioned hereinabove can be combined with one another. For example, a counter-deflection stop blade can be used in the embodiment of FIG. 9. Plates, such as the plate 30 of the embodiment of FIG. 6, can be used in the other embodiments, in addition to or in replacement of a counter-deflection stop blade. It is not necessary to use a spring, such as the spring 48, in the embodiments equipped with a counter-deflection stop blade.

The invention has been described in relation to a twin tip freestyle ski. It however applies to other types of skis, in particular a ski of which only the front tip is raised, i.e., the tail having an otherwise conventional shape.

The embodiments and alternative embodiments have been described hereinabove by way of example, and the invention encompasses any and all equivalent embodiments.

The invention illustratively disclosed herein suitably may be practiced in the absence of any element which is not specifically disclosed herein.

Claims

1. An alpine ski comprising:

a mounting zone for mounting a binding, the mounting zone being centered on a mounting point;

a front end and a rear end;

a sole;

at least a single particular flexion deformation zone consisting of a single particular front flexion deformation zone between the mounting zone and the front end of the ski and/or a single particular rear flexion deformation zone between the mounting zone and the rear end of the ski;

said particular flexion deformation zone being centered on a softening point positioned, in relation to the mounting point, at a distance ranging between 360 and 480 mm.

2. An alpine ski according to claim 1, wherein:

the particular flexion deformation zone is arranged so that, under a static load of 900 Newtons, applied to the center of the particular flexion deformation zone and along a direction perpendicular to the ski sole, the deformation zone adopts a generally dihedral configuration having a deflection greater than or equal to 13 mm, the ski being supported on two rods arranged under the sole, symmetrically on both sides of the particular flexion deformation zone and spaced from one another by an axial distance equal to 400 mm.

3. An alpine ski according to claim 2, wherein:

said deflection is equal to approximately 15 mm.

4. An alpine ski according to claim 1, wherein:

the particular flexion deformation zone extends, in relation to the mounting point of the binding zone over an axial distance ranging between 285 and 365 mm.

5. An alpine ski according to claim 1, wherein:

the particular flexion deformation zone is a zone having a reduced thickness with respect to the mounting zone, on the one hand, and with respect to a zone extending between the particular flexion deformation zone and said one of the ends of the ski, on the other hand.

6. An alpine ski according to claim 5, wherein:

the particular flexion deformation zone has a minimal thickness ranging between 6 and 8 mm, and wherein the zone extending between the particular flexion deformation zonel has a minimal thickness ranging between 8.5 mm and 11 mm.

7. An alpine ski according to claim 1, wherein:

the particular flexion deformation zone is formed by a fitting made out of a more flexible material than constituent material(s) of the mounting zone and end zones of the ski.

8. An alpine ski according to claim 1, wherein:

the particular flexion deformation zone is equipped with means for limiting or controlling deformation of the ski in the particular flexion deformation zone.

9. An alpine ski according to claim 8, wherein:

the limiting or controlling means include a plate fixed on the upper surface of the ski and which is mechanically biased as a function of deformation of the ski in the particular flexion deformation zone.

10. An alpine ski according to claim 1, wherein:

the at least a single particular flexion deformation zone comprises two particular flexion deformation zones, said two particular flexion deformation zones consisting of a first deformation zone arranged between the mounting zone and the front end of the ski, and a second deformation zone arranged between the mounting zone and the rear end of the ski.