WO1995031259A1

WO1995031259A1 - Ski with a cross-country skiing device

Info

Publication number: WO1995031259A1
Application number: PCT/FR1995/000495
Authority: WO
Inventors: François Girard; Jacques Quellais
Original assignee: Salomon S.A.
Priority date: 1994-05-11
Filing date: 1995-04-14
Publication date: 1995-11-23
Also published as: EP0708672A1; CA2166894A1; FR2719782A1; FI960113A; NO301867B1; FI960113A0; NO960086D0; NO960086L; FR2719782B1

Abstract

A ski comprising complementary members (11, 12, 13) for amplifying the force exerted by the skier as he or she kicks forward on the ski (1), while helping to reduce the length of an upper fibre (3) of said ski for the same purpose, and making it easier to press a wax chamber (6) of the ski (1) against the snow. Said members are arranged as the interface between the ski (1) and a binding (7) perpendicular to the wax chamber (6), and include a resilient return member enabling controlled movement of the toe portion (7a) of the binding device (7).

Description

SKIING EQUIPPED WITH A CROSS-COUNTRY SKIING DEVICE

Cross-country skiing with a dynamic boot fixing device.

The present invention relates to a cross-country ski in particular for the practice of the alternative pitch which is defined longitudinally by a lower fiber and an upper fiber whose distance separating them forming the thickness of the ski, is progressive to form, on the one hand two zones relatively thin and smooth end constituting the heel and the tip of the ski and intended for the gliding phase after an impulse and on the other hand, a thicker and arched central zone at rest upwards and defining on its lower fiber a hanging zone or wax chamber intended to come into contact with the snow by elastic deformation during an impulse phase, the upper fiber of said central zone receiving at the right of the wax chamber a fixing device ensuring the anchoring of the front of the boot, the heel of the boot remaining free to move freely for a smooth running of the foot when skiing.

During the exercise of the alternative step, this support of the foot manifests itself between the sole of the ski and the snow, essentially at two very limited points or zones, well located.

During the impulse for forward progression, the skier's foot is supported at the level of the metatarsophalangeal joint, which defines the position of the fulcrum on the ski or impulse fulcrum. It is at this point that the maximum pressure is exerted to flatten the ski by elasticity against the camber of the wax chamber.

In the sliding or advancing phase of the ski, it is by the heel that the skier rests on the ski. Due to the original camber of the ski, and the relative position of the foot with respect thereto, this support of the heel leaves in front of its point of application a cambered residual zone which therefore corresponds to zero pressure of the skiing on the ground. It is indeed in this wax area or chamber that it is most advisable to apply to the sole of the ski a retaining wax or any other means opposing recoil, such as scales, anti-chemical coating. recoil, etc. The retaining wax, or any other means, produces an effect only by its contact with the ground, that is to say during the impulse phase by preventing the ski from retreating, by the positive reaction that the soil can then exert on it. In order to optimize the grip of the wax chamber on snow, means have been sought which make it possible to improve the performance of the ski by acting on the slip-grip compromise.

It was thus determined that for a better effectiveness of the impulse, the top of the arch of the wax chamber must be positioned substantially at the level of the nail of the big toe and correspond to the point of balance, possibly a centimeter behind. towards the heel.

If the top of the above arch is not in the right place (too far forward) there will be a loss of wax between the metatarsals and the heel. This metatarsal-heel area is very important, because it corresponds, at the end of the gliding phase, to the maximum pressure to be exerted for the skier, in order to obtain maximum impulse.

Furthermore, when taking the impulse in steps of one, the support is maximum when the foot is flat, the skier's body being above the only foot in contact with the ground, then it is the unfolding of the foot which results in a reduction of the pressure force of the foot on the ski.

Optimizing the pulse-slip compromise corresponding successively to a motor phase and a rest phase has already been sought by trying to improve the quality of the grip during the pulse.

For this, it is known from French document No. 2,556,975 a device comprising a membrane disposed in the area of the wax chamber and which can be pushed down beyond the lower plane of the ski under the effect of elastic control members urged by a mechanism in connection with the front of the skier's foot, in order to bulge said membrane. This results in a large dimension recess on the bottom wall of the ski, of course tending to reduce its resistance. In addition, such a device is rather intended for braking during sliding, than for impulses.

According to German document No. 33 03 093, it is proposed to improve the grip in the impulse phase by creating an indispensable element of the ski comprising saw teeth directed towards the rear, said element passing through the ski under the action of the foot during an impulse in order to block a relief of the vaulted wall of the wax chamber so that the ski does not undergo a retrograde sliding effect in this phase.

Such a solution also has the drawback of weakening the ski and moreover does not modify the effort to be provided by the skier. Is also known from the French document n ° 2 666 021 a system consisting once again in making a recess in a central transverse zone of the ski to improve the flexibility thereof, but by weakening it in return and without possibility no adjustment depending on the skier.

In order to remedy these various drawbacks, the invention relates to a cross-country ski in particular for the practice of the alternating pitch which is defined longitudinally by a lower fiber and an upper fiber whose distance separating them forming the thickness of the ski, is progressive to form, on the one hand two relatively thin and smooth end zones constituting the heel and the tip of the ski and intended for the gliding phase after an impulse and on the other hand, a thicker and arched central zone at rest upwards and defining on its lower fiber an attachment zone or wax chamber intended to come into contact with snow by elastic deformation during an impulse phase, the upper fiber of said central zone receiving at the right of the wax chamber a fastening device ensuring the anchoring of the front of the shoe, the heel of the shoe remaining free to move freely for a smooth running of the foot during the practice of skiing, characterized in that during the impulse phase taking place according to a given effort of the skier, additional means capable of amplifying the effort provided, while helping to reduce the length of the fibers located in the upper half of the ski between two reference points arranged in this area, in line with the wax chamber, are interposed at the interface between the ski and the binding device making it dynamic according to a controlled travel of its front part, which means are used at the time of the said pulse to contribute positively to causing the deformation of the upper fibers of the said chamber with a view to pressing it more easily on the snow, so as to be able to exert an application force on the wax chamber, which is superior to the effort provided and according to a better concentration of it.

To these advantages are also added the fact that these means confer a greater speed of action in the impulse phase, for the benefit of a longer gliding or rest period by reducing the motor impulse phase. Also given the development of forces, the length of the wax chamber can be reduced.

We can also plan to customize the ski according to the weight of the skier and the stiffness of the ski by adjusting the binding forces on skiing so that any skier can ski on any ski.

The invention will be better understood and other characteristics of it will be highlighted with the aid of the description which follows, with reference to the appended diagrammatic drawing, representing by way of nonlimiting example, how the invention can be performed and in which:

- Figures 1 and 2 show a portion of cross-country skiing provided with amplification means according to a first embodiment of the invention, respectively in gliding phase and in pulse phase;

- Figure 3 shows a cross-country ski provided with amplification means according to a second embodiment of the invention;

- Figures 4 and 5 show a portion of cross-country skiing provided with amplification means according to a third embodiment of the invention, respectively in gliding phase and in pulse phase;

- Figures 6 and 7 show a cross-country ski portion provided with amplification means according to a fourth embodiment of the invention, respectively in gliding phase and in pulse phase;

- Figures 8 and 9 show diagrams showing the distribution of contact pressures between the heel and the metatarsals of the foot, respectively according to the known prior art and the invention.

As shown in FIG. 1, the cross-country ski 1 is defined longitudinally by a lower fiber 2 and an upper fiber 3, the distance "d" separating them forming the thickness of the ski 1 is progressive. This progressiveness makes it possible to form on the one hand two relatively thin and smooth end zones constituting the heel and the tip of the ski 1, not shown in the figure, intended for the gliding phase after an impulse and on the other hand a zone thicker and vaulted central unit at rest upwards, defining on its lower fiber a hanging zone or wax chamber 6 (see FIG. 3). This chamber is intended to come into contact with snow by elastic deformation during an impulse given by the skier. The upper fiber 3 of said central area receives, to the right of the wax chamber 6, a fastening device 7 ensuring the anchoring of the shoe 8 from the front 9, the heel 10 thereof remaining free to move in full freedom for a smooth running of the foot when skiing. This technique being well known, it will not be developed further here.

According to the invention, various embodiments of which will be cited and described below, during the pulse phase taking place according to a 5 given effort of the skier, additional means capable of amplifying the effort provided, while helping to reduce the length of the fibers located in the upper half d1 of the ski 1 between two reference points arranged in this area, in line with the room to wax 6, are interposed at the interface between the ski 1 and the binding device 7 making it dynamic according to a controlled deflection of its front part, which means are used at the time of said pulse to contribute positively to causing deformation upper fibers of said chamber 6 in order to more easily tackle it on the snow, so as to be able to exert an application force on the wax chamber 6, greater than the force supplied and according to a better concentration thereof .

According to the exemplary embodiment shown in FIGS. 1 and 2, the complementary means for amplifying the force provided consist of a weakened zone 1 1 carried out transversely on the upper fiber 3 of the ski 1 to promote the deformation of the chamber to wax 6 according to a local concentration chosen as a function of the maximum pressure point exerted on the ski 1 at the time of the pulse.

More specifically, the weakened area 1 1 is produced near the front binding 7a of the boot 8 corresponding substantially to the point of maximum pressure on the ski 1 at the time of the pulse.

According to the present example, the weakened zone 11 is constituted by a transverse cylindrical recess of which an open upper lateral part 11 delimited by two generatrices 11b, 11c of the cylinder according to a spacing e chosen, opens onto the upper fiber 3 of the ski 1.

The force exerted by the skier in the impulse phase, and corresponding to the pressure applied to said ski 1 in its weakened zone 1 1, is transmitted by an intermediate plate 12 of elastic fibers, on the upper part 12a of which is disposed the fastening device 7 of the boot 8, its lower rear part 12b, located at the heel 10 of the boot 8 being integral with the upper fiber 3 of the ski 1, while its lower front part 12c located at the front 9 of the boot 8 from which its front binding 7a is free in angular movement according to an amplitude ai controlled so as to be pressed against the upper fiber 3 of the ski 1 in the weakened zone 11, in a pulse phase, then to be recalled by an elastic force F in its initial position, in a sliding phase.

Figures 1 and 2 clearly show that in the gliding phase (Figure 1), the only force exerted on the ski 1 is the weight P of the skier, while in impulse phase, the force produced is added to the value P to obtain P '> P and> F, the latter value being the elastic restoring force of the intermediate plate 12.

According to another characteristic specific to this same embodiment, the control of the amplitude of the angular movement ai of the front end of the elastic intermediate plate 12 is carried out by two lateral yokes 13 arranged on the ski 1 on both sides and d other from the front end of said elastic plate 12, said yokes 13 comprising lights 14, in each of which is capable of struggling with a rod 15 secured to the front end of said elastic plate 12.

The lights 14 formed in the yokes 13 are symmetrical with one another and are inscribed in triangles in which the rod 15 is liable to struggle between on the one hand a higher position I in which it cooperates in the sliding phase, with the apex of the triangle under the influence of the force F generated by the intermediate plate 12 and constituting its elastic return simultaneously ensuring the stiffness of the ski 1 despite the weakened zone 11 practiced on the upper fiber 3, and on the other hand a lower position II in which said rod 15, after being released from the top of the triangle during the exercise of an effort of the skier in the impulse phase, of value P 'greater than his own weight P, is free in longitudinal movement within limits of the angle a defining the length of the base of the triangular lights 14, this so as to allow said rod 15 to perform a trajectory in an arc of a circle, during which the z one weakened 1 1 tightens on itself (Figure 2) and thus authorizes a tacking of the wax chamber 6 on the snow with a better concentration of the force P 'produced by the skier.

It can also be seen according to FIGS. 1 and 2 that the length D of the upper fiber 3, in the pulse phase and consequently of the wax chamber 6, is less than the length D in the sliding phase.

According to an alternative embodiment shown in FIG. 3, the complementary means of amplitude of the effort provided by the skier in the impulse phase consist of a cable 16, one of its ends 16a being integral with one reference points 17 of the upper fiber 3 disposed towards the tip 5 of the ski 1.

The cable 16 fixedly connects a rear part 7b of the fastening device 7 in the heel area 10 by an intermediate pulley 18 constituting the second reference point disposed towards the heel 4 of the ski 1.

In this way, the fixing movement 7 relative to the ski 1 to which it is connected by a fixed intermediate point of rotation 19 causes in the impulse phase, a pull of the cable 16 exerting tension on the upper fiber 3 of the ski 1, helping to apply the wax chamber 6 on snow.

According to an alternative embodiment shown in FIGS. 4 and 5, the additional means for amplifying the effort provided by the skier in the impulse phase consist of a cable 20, one of its ends 20a being integral with a first reference point 21 located on the upper fiber 3 of the ski 1, disposed towards its tip 5, opposite a second reference point 22 constituting an articulation point of the fixing device 7. The cable 20 connects fixedly a lower part 23a of a link 23 interposed between the upper fiber 3 of the ski 1 and the lower face 7c of said binding device 7. Said link 23 is integral with the latter by means of a joint 23b, its other end 23a directed towards the upper fiber 3 of the ski 1 being free in angular movement and connected to the other end 20b of the cable 20. In this way, during the supply of a force P 'exerted on the device fastening 7, during a pulse phase, the link 23 describes a movement in an arc of circle until it is flattened by driving the cable 20, which consequently causes traction on the first reference point 21 from where the upper fiber 3 of ski 1.

Thus under the pressure of the weight P of the skier to the metatarsals, therefore P 'at the moment of the impulse, the angle a3 becomes a4 either: a3> a4. The link 23 closes and causes the cable 20 to move back towards the binding 7 causing the length D to become D ’because the reference points 21 and 22 are fixed on the upper fiber 3 of the ski 1. Consequently, if D> D 'the ski 1 is flattened and the wax chamber 6 touches the snow.

Such a device interposed between the binding device 7 and the ski 1 has the effect of delaying the support signal on the wax chamber 6 which has the positive consequence of increasing the sliding phase.

As already mentioned, the fact of amplifying the force increases the support of the wax chamber and allows the support on the snow to be maintained at a lower value P ′, which has the positive consequence of increasing the hanging phase. 8

According to a fourth alternative embodiment shown in FIGS. 6 and 7, the additional means for amplifying the effort provided by the skier in the impulse phase consist of a plate 25 interposed between the upper fiber 3 of the ski 1 and the fixing device 7, its end 25b directed towards the spatula 5 is connected by a first articulation 26 to the upper end of a vertical control lever 27.

The control lever 27 passes through the upper fiber 3 of the ski 1 in order to plunge into a blind recess 28 formed in the core of the ski in an upper zone of the latter, the lower end of the vertical lever 27 comprising a second articulation 29 on which in turn are articulated, by one of their ends, two rods 30, 31, each of their other ends being connected respectively to a third and to a fourth articulation 32, 33.

The latter are in connection with the end 34a of a first cable 34 secured to a first fixed reference point 36 of the ski 1 directed towards the heel 4 and to the end 35a of a second cable 35 secured to a second fixed reference point 37 of the ski 1 directed opposite the first 36, towards the tip 5.

In this way, during a downward action of the lever 27, during an impulse phase, the latter drives the two rods 30, 31 in its descent causing, by deformation of their geometry, a traction on the two cables 34, 35, driving them towards each other and consequently exerting traction on at least one of the fibers of the ski 1 located in its upper half d1 of the wax chamber 6 on the snow.

Furthermore, the traction cables 34, 35 join their respective reference points 36, 37 by means of sheaths formed in the core of the ski 1, in its upper half d1.

The elastic return of the control lever 27 after an impulse phase is effected by the elasticity of the intermediate support plate 25 of the fixing device 7.

Preferably or jointly, as shown in FIGS. 6 and 7, the elastic return of the control lever 27 after an impulse phase is effected by a compression spring 38 interposed between the end of said lever 27 in articulated connection with the links 30 , 31 and the bottom 28a of the housing 28 of the ski 1 in which it dives. We will now proceed, in a general manner to the comparison of the diagrams noted during the use of a conventional ski and a ski provided with a dynamic binding according to the invention.

For a conventional ski intended essentially for alternative pitch, it can be seen, as illustrated in FIG. 8, that this pressure distribution along the ski 1 is not ideal. This diagram represents the contact pressure PC on the ordinate, as a function of the position on the ski on the abscissa, between the tip 5 and the heel 4 of the ski, respectively in the impulse phase, in phantom, and in the slip, in solid line. The impulse and heel support points are respectively referenced by A and B. It can be seen that if, in the sliding or support phase of the heel, the wax chamber 6, or zone of zero pressure, does exist and well, during the pulse phase (mixed line), the pressure, which is obtained at the point of pulse A, is in fact distributed on either side of this point in a very broad and diffuse manner on the one hand, and with relatively little intensity, in the area of the wax chamber 6 on the other hand, which very significantly harms the effectiveness of the pulse.

Compared with the diagram in FIG. 8, the diagram in FIG. 9 shows in which advantageous proportions the pulse curve, with a ski provided with amplification means according to the invention, in dotted lines, reaches a value of force exerted on skiing, much higher in this phase (4.5 kg instead of 2.2 kg, more than double), while in the gliding phase, in full line, the effort is reduced.

Claims

1 - Cross-country skiing (1), in particular for the practice of the alternative pitch, which is defined longitudinally by a lower fiber (2) and an upper fiber (3) whose distance separating them, forming the thickness of the ski (1) , is progressive to form, on the one hand two relatively thin and smooth end zones constituting the heel (4) and the tip (5) of the ski (1) and intended for the gliding phase after an impulse and other part, a thicker central area and arched at rest upward and defining on its lower fiber a hanging area or wax chamber (6) intended to come into contact with snow by elastic deformation during a phase of impulse, the upper fiber (3) of said central zone receiving at the right of the wax chamber a fixing device (7) ensuring the anchoring of the front (9) of the shoe (8), the heel (10) of it remaining free to move freely for a smooth running of the foot during practice. as skiing, characterized in that during the impulse phase taking place according to a given effort of the skier, additional means capable of amplifying the effort provided, while helping to reduce the length of the fibers located in the upper half (d1) of the ski (1) between two reference points arranged in this area, in line with the wax chamber (6), are interposed at the interface between the ski (1) and the fixing device (7) making it ci dynamic according to a controlled deflection of its front part, which means are used at the time of said pulse to contribute positively to causing the deformation of the upper fibers of said chamber (6) in order to more easily tackle it on snow, so as to be able to exert an application force on the wax chamber (6), greater than the force supplied and according to a better concentration thereof.

2- Ski according to claim 1, characterized in that the complementary means of amplification of the force provided consist of a weakened zone (1 1) carried out transversely on the upper fiber (3) of the ski (1) to promote the deformation of the wax chamber (6) according to a local concentration chosen as a function of the maximum pressure point exerted on the ski (1) at the time of the pulse.

3- Ski according to claim 2, characterized in that the weakened zone (11) is produced near the front binding (7a) of the boot (8) corresponding substantially to the point of maximum pressure on the ski (1) at the time of the impulse. 4- Ski according to claim 2 or 3, characterized in that the weakened zone (1 1) is constituted by a transverse cylindrical recess of which an open upper lateral part (1 1 a) delimited by two generators (11 b, 1 1 c ) of the cylinder according to a spacing (e) chosen, leads to the upper fiber (3) of the ski (1).

5- Ski according to one of claims 2 to 4, characterized in that the force exerted by the skier in the impulse phase, and corresponding to the pressure applied to said ski (1) in its weakened zone (11), is transmitted by an intermediate plate (12) made of elastic fibers, on the upper part (12a) of which is arranged the fastening device (7) of the shoe (8), its lower rear part (12b), located at the level of the heel (10) of the boot (8) being integral with the upper fiber (3) of the ski (1), while its lower front part (12c) located at the front (9) of the boot (8) hence its front attachment (7a) is free in angular movement according to an amplitude (ai) controlled so as to be pressed against the upper fiber (3) of the ski (1) in the weakened zone (11), in its phase momentum, then to be recalled by an elastic force (F) in its initial position, in a sliding phase.

6- Ski according to claim 5, characterized in that the control of the amplitude of the angular movement (ai) of the front end of the elastic intermediate plate (12) is carried out by two lateral yokes

(13) arranged on the ski (1) on either side of the front end of said elastic plate (12), said yokes (13) comprising lights (14), in each of which is capable of struggling a rod (15) secured to the front end of said elastic plate (12).

7- Ski according to claim 6, characterized in that the lights

(14) practiced in the yokes (13) are symmetrical with one another and are inscribed in triangles in which the rod (15) is liable to struggle between on the one hand a higher position (I) in which it cooperates in phase sliding, with the top of the triangle under the influence of the force (F) generated by the intermediate plate (12) and constituting its elastic return simultaneously ensuring the stiffness of the ski (1) despite the weakened area (1 1) practiced on the upper fiber (3), and on the other hand a lower position (II) in which said rod (15), after being released from the top of the triangle during the exercise of an effort of the skier in phase of pulse, of value (P ¹ ) greater than its own weight (P), is free in longitudinal movement within the limits of the angle (a) defining the length of the base of the triangular lights (14), so as to allow said rod (15) to carry out a trajectory in an arc of circle during which the weakened zone (1 1) tightens on itself and thus authorizes a plating of the room wax (6) on snow with better concentration of the effort produced by the skier.

8- Ski according to claim 1, characterized in that the complementary means of amplitude of the effort provided by the skier in the impulse phase consist of a cable (16) one of its ends (16a) is integral with one of the reference points (17) of the upper fiber (3) disposed towards the tip (5) of the ski (1) and fixedly connecting a rear part (7b) of the fixing device (7) in the area of the heel (10) by an intermediate pulley (18) constituting the second reference point disposed towards the heel (4) of the ski (1) so that the fixing clearance (7) relative to the ski (1) to which it is connected by a fixed intermediate point of rotation (19) causes in the impulse phase, a pull of the cable (16) exerting tension on the upper fiber (3) of the ski (1), helping to apply the wax chamber (6) on snow.

9- Ski according to claim 1, characterized in that the additional means for amplifying the effort provided by the skier in the impulse phase are constituted by a cable (20) one of its ends (20a) is integral with a first reference point (21) located on the upper fiber (3) of the ski (1), disposed towards its tip (5), opposite a second reference point (22) constituting a point of articulation of the fixing device (7), said cable fixedly connecting a lower part (23a) of a link (23) interposed between the upper fiber (3) of the ski (1) and the lower face (7c) of said device fixing (7), said link (23) being integral with the latter (7) via a joint (23b), its other end (23a) directed towards the upper fiber (3) of the ski (1) being free in angular movement and connected to the other end (20b) of the cable (20), so that when supplying a n force (P ¹ ) exerted on the fixing device (7) during an impulse phase, the link (23) describes a movement in an arc of circle until it is flattened by driving the cable (20), which consequently causes traction on the first reference point (21) hence on the upper fiber (3) of the ski (1).

10- Ski according to claim 1, characterized in that the additional means for amplifying the effort provided by the skier in the impulse phase consist of a plate (25) interposed between the upper fiber (3) of the ski (1) and the binding device (7), its end (25b) directed towards the tip (15) is connected by a first articulation (26) to the upper end of a lever vertical control (27) passing through the upper fiber (3) of the ski (1) to plunge into a blind recess (28) formed in the core of the ski in an upper zone thereof, the lower end of the vertical lever (27) comprising a second articulation (29) on which two rods (30, 31) are articulated in turn, at one of their ends, each of their other ends being connected respectively to a third and to a fourth articulation (32, 33) in connection with the end (34a) of a first cable (34) secured to a first reference point (36) fixed to the ski (1) directed towards the heel (4) and with the end (35a) of a second cable (35) secured to a second fixed reference point (37) of the ski (1) directed at the op placed from the first (36), towards the spatula (5), so that when the lever (27) is pressed down, during an impulse phase, the latter causes it to descend the two rods (30, 31) causing by deformation of their geometry, a traction on the two cables (34, 35), driving them towards each other and consequently exerting traction on at least one of the fibers of the ski (1) located in its upper half (d1) of the wax chamber (6) on snow.

1 1- Ski according to claim 10, characterized in that the traction cables (34, 35) join their respective reference points (36, 37) by means of sheaths formed in the core of the ski (1), in its upper half (d1).

12- Ski according to one of claims 10 or 11, characterized in that the elastic return of the control lever (27) after an impulse phase is effected by the own elasticity of the intermediate support plate (25) of the device. fixing (7).

13- Ski according to one of claims 10 or 11, characterized in that the elastic return of the control lever (27) after an impulse phase is effected by a compression spring (38) interposed between the end of said lever (27) in articulated connection with the links (30, 31) and the bottom (28a) of the housing (28) of the ski (1) in which it dives.