FR2742343A1 - SLIDING BOARD EQUIPPED WITH A DEVICE TO MODIFY THE STIFFNESS OF THE BOARD UNDER THE EFFECT OF A VERTICAL THRUST GIVEN BY THE USER - Google Patents

Abstract

The ski/snow-board has a sliding lower surface, an upper surface (10) with boot fastenings (4,5), and a regulator to control the rigidity of the board with foot pressure. The regulator consists of a platform (2) with the boot fastenings, a central support with a pivot (8), and cams (14,16,18,19) at each end which help to vary the curvature of the board's sliding surface. The cams are located on the upper surface of the board and the under surface of the platform and have facing sloping surfaces which can be coated with a material with a low friction coefficient, e.g. PTFE. Alternatively, one of the cams in each pair can be in the form of a cylindrical roller. Alternatively, the rear end of the platform can be connected to the upper surface of the board by a rigid strip, e.g. of aluminium, or the rear portion of the platform can be supported by a rigid or semirigid plate of a visco-elastic material with a minimum Shore A hardness of 80.

Description

i

  SLIDING BOARD HAVING A DEVICE INTENDED FOR

  MODIFYING THE STIFFNESS OF THE PLATE UNDER THE EFFECT OF

  VERTICAL GROWTH GIVEN BY THE USER

  TECHNICAL FIELD The invention relates to the field of snow sliding sports. It relates more particularly to gliding boards equipped with a device interposed between the binding and the top of the board for interactively adapting the characteristics of the board to different positions and intensities of the pulse forces observed during of the

  practice of sport, especially during the making of a turn.

  Subsequently, the invention will be described in its more particular application to alpine skiing, without excluding from the scope of the invention other snow sliding sports such as monoski or snowboard.

snowboard.

  PRIOR ART In particular, the invention aims to optimize the behavior of a ski during the making of a turn, it is first necessary to specify the different phases and the position of the forces transmitted by the skier to the ski during a turn. Very schematically, we can break down a turn into three essential phases, namely the triggering, the driving

and the exit of the turn.

  During the turn initiation phase, the skier carries his body weight towards the inside of the turn and forward. The ski must then bend to inscribe his inner edge in a curve. To reduce the radius of curvature of this trajectory, the skier's impulse, that is to say the force it exerts on the ski must be greater than to make a turn with a large radius. It has been observed that the impulse exerted can

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  to reach a force corresponding to five to eight times the weight of the skier.

  To facilitate the curvature of the ski during this triggering phase, it is necessary that the ski sufficiently flexible and that the application of the load of the skier on the ski is practically punctual, in order to obtain a short skiing behavior. During the phase of driving the turn, the position of the skier backs down so that the weight of his body is practically applied at the level of the middle of the shoe. In this phase, the ski maintains its

radius of curvature.

  Finally, at the exit of the turn, the skier moves his weight of the body towards the rear, so the skier's support zone on the ski moves towards the heels of the shoes. During this phase, it is better to have a steeper ski, behaving like a ski of greater length to improve its stability. In this phase, the weight of the skier must be

  spread over the maximum length of the ski.

  It is therefore conceivable that, ideally, the ski must behave like a short ski and very flexible when triggering and driving the turn, then turn into a long and steep ski for the

driving phase.

  Document FR-A-2 702 386 of the applicant describes a hydraulic device for, depending on the location before or after the skier's thrust, the modification of the general stiffness of the ski. Although satisfactory and giving appreciable results, this solution needs to be implanted inside the thickness of the ski, which requires relatively complex operations and economically little

profitable.

  Documents FR-A-2,684,885, FR-A-2,686,798, FR-A-2,686,799, FR-A-2,690,079 and FR-A-2,713,945 have also been proposed. to modify the natural pressure distribution of a ski on its sliding surface. These devices are installed under the sole of the shoe, between the abutment and the heel of the binding and allow by a system of arms, levers and rockers operated during the boot of the shoe to exert tension on the ski. Unfortunately, this device requires a large number of parts that have hinge axes particularly stressed, and therefore fragile especially in the conditions of use (humidity and cold) and more generating mechanical games. In addition, they do not dynamically modify the stiffness of the ski according to the position of the skier. They do not substantially vary the stiffness of the ski in use, depending on the location of the support exerted by the skier. These devices modify the stiffness of the ski and its camber from the introduction of the shoe into the binding,

  only by applying the load on the heels of the shoes.

  The problem to be solved by the invention is to provide a ski whose stiffness evolves dynamically during the different phases of the turn. The goal is to give the ski a behavior equivalent to that of a short and flexible ski during the front supports at the beginning of the turn, and alternatively the behavior of a long and steep ski during

  rear supports present for the terminal phase of the turn.

  Moreover, the document WO 95/00217 describes a double device intended to influence the stiffness characteristics of the skis and their bending as a function of the supports exerted by the skier. This double device is constituted by two articulated interfaces mounted respectively under the abutment and under the heel of the binding. Unfortunately, on the one hand, the system is very floating which causes unacceptable loss of precision; on the other hand, the interfaces are symmetrical and cause practically the same effects during front and rear support. Last but not least, the arms of levers involved are much too short for

  generate significant forces.

  SUMMARY OF THE INVENTION The invention relates to a gliding board having a lower sliding surface and an upper face intended to receive a safety binding adapted to secure the user's shoe to the board, the board being equipped at the level of the board. fastenings of a stiffening device intended to modify the stiffness of the board under the effect of a thrust

  exerted by the user towards the upper face of the board.

  This gliding board is characterized in that the stiffening device comprises: an elongated upper platform intended to receive the fastening on its upper face, said platform being raised with respect to

  the upper face of the board and positioned in a cantilevered position

  above it; at least one point of connection of the platform with the upper face of the board; means for modifying the stiffness of the board in a differentiated manner as a function of the position, relative to said connection point, of the point of application of the thrust exerted by the user

on the platform.

  The point of connection is preferably located substantially at

  level of the middle zone of the shoe.

  In other words, the platform interposed between the binding and the board has a longitudinal inclination capacity depending on the location to the front (at the beginning of the turn) or back (at the end of the turn). In this way, the platform cooperates with additional means making it possible to increase or reduce the stiffness of the

  board, depending on the phase of the turn.

  In other words, thanks to the invention, a ski intrinsically

  steep is helped in bending during the turn initiation phases, ie

  that is, when the force is exerted in front of the point of connection, which makes the behavior easier. Conversely, a ski that is naturally "supple" is stiffened during the end of the turn, that is to say when the skier's load is exerted behind the median position.

  of the shoe, which improves the driving.

  In a first embodiment, the point of connection of the platform with the board is located substantially at the middle zone of the shoe. It is in the form of pivot articulation allowing the longitudinal inclination of the platform relative to the board. Thus, the platform is pivotally mounted relative to the board and its forward or backward tilt directly results from thrusts located respectively forward or backward. In various embodiments, the characteristic means intended to modify the stiffness of the board are: either partially located at the rear of the platform and are able to band the area of the ski situated between the hinge pin and said means ; - Or partly located at the front of the platform and are able to facilitate the bending of the ski area between the pivot pin and said means;

  - still located at the front and rear of the platform.

  In this way, the characteristic means arranged towards the front of the platform allow to soften, when triggering the turn, a moderately steep ski, while when these means are arranged towards

  the back, they allow the stiffening of the same ski.

  Of course, it is better to combine these two effects for

obtain optimal behavior.

  Advantageously in practice, the characteristic means consist of cams respectively implanted on the platform and on the upper face of the ski, at least one of the cam surfaces being constituted by a sloping surface whose orientation is directed towards

forward and down.

  In other words, the application of a vertical thrust is converted, by the relative sliding of cam surfaces, into a longitudinal displacement of one of the parts of the platform. In a first case, this displacement causes a reconciliation of fixed points on the ski, and thus a bending aid, while in another case, this displacement results in a spacing of fixed points on the ski, so a bandage of the ski . In a particular embodiment, one of these cam surfaces may be constituted by a cylindrical roller whose axis of revolution is parallel to the axis of articulation of the plate of the platform. In another embodiment, the characteristic means for modifying the stiffness of the board consist of a point

  support from the back of the platform on the back of the board.

  In other words, when the platform tilts backwards, the rear part of this platform exerts on the back of the ski, a directed thrust

  perpendicular to the surface of the sole.

  In a practical embodiment, the support point consists of a plate forming a rear extension of the platform, the rear end of the plate being secured to the upper face of the ski. In other words, in this case, the rear end of the platform is connected and fixed on the upper face of the ski. In this way, when tilting the platform forward around its pivot hinge, the rear end of the platform tends to pull the board up and induce bending. Conversely, when the rear supports, the inclination towards the rear of the platform, pushes this point of support and causes the stiffening

of the board.

  In an alternative embodiment, the fulcrum is integral with the

ski songs.

  In another embodiment, the connection between the platform and the top of the board is made by a plate interposed between the platform and the top of the board, at the rear of the level of the area.

median of the shoe.

  Thus, the front part of the platform is found in overhang. In this way, when the supports directed forward, the front portion of the platform tends to bow, causing the rise of the rear end of the platform and thus the bending of the ski. On the contrary, when the supports are directed towards the rear, the interposed characteristic plate makes it possible to transmit the forces over a great length, giving the

  skier a stiff and long skiing sensation.

  In this embodiment, one can assimilate the front end of

  the plate interposed with the hinge pin.

  To improve the comfort of the device, the interposed plate can be made of viscoelastic material with a hardness of about 80 Shore A

minimum.

Brief description of the figures

  The way to realize the invention as well as the advantages which

  result will emerge from the description of the embodiments which

  follow in support of the appended figures in which: Figure 1 is a simplified side view of the skid zone of a ski equipped with the device according to the invention, in the absence of thrust

exercised by the user.

  Figures 2 and 3 are side views of the same device shown in a pulse exerted respectively forward and backward. FIG. 4 is a side view of an embodiment variant of FIG.

the invention, shown at rest.

  Figures 5 and 6 are the representation of the deformations of the same device in pulses exerted respectively forward and backward. Figure 7 is a side view of another embodiment of the invention in which the front part of the platform is cantilevered. Fig. 8 is a side view of the device of Fig. 8 shown

  with a forward pulse.

  Ways of Realizing the Invention As already stated, the invention relates to a board for gliding

  general, but the description that follows only describes its application to a ski

  Alpine, the transposition to another sport of gliding obviously imposes for a man of trade. The invention therefore aims at a ski which has at its zone

  pad a platform for receiving a security attachment.

  The invention consists in providing this platform with complementary means making it possible to modify the stiffness of the ski, in a differentiated manner, when the skier exerts a vertical impulse towards the front or towards the rear of the platform. Several architectures and localizations of these means allow

  to achieve the desired results.

  In order to simplify the explanation, it is considered that the ski is laid horizontally flat, so that the pulses

  generated by the skier are vertical.

Example 1

  In the embodiment illustrated in FIGS. 1 to 3, the board (1) receives at its skid zone an elongate and rigid platform (2) on the upper face (3) of which the stop (4) is arranged and the heel

  (5) responsible for maintaining the shoe (6) of the user.

  This rigid platform (2) has at the level of the central zone (7) of the shoe (6), a hinge axis (8) connecting the transverse with a chappe (9) integral with the upper face (10) of the ski . Of course, this chappe (9) can be disposed inside a recess (not shown) provided for this purpose on the upper face (10) of the ski. Furthermore, the articulation could also be performed by reversing the relative positions of the axis (8) and the chappe (9), that is to say by mounting the chappe (9) under the platform (2) and articulating it with respect to an axis

in solidarity with the ski.

  This platform (2) presents characteristic means in its

  front (11) and rear (12) extremal parts.

  Thus, in the front portion (11), the lower face (13) of the platform (2) has a sloped wedge (14) whose slope (15) is directed forward and downwardly. Complementarily, the upper face (10) of the ski has a sloping wedge (16) opposite, whose slope (17) is identical to that (15) of the wedge (14) of the platform (2), and therefore oriented towards down and forward. It is obvious that one of these sloped wedges (14, 16) can be replaced by another form of cam surface, in particular by a

  cylindrical roller (not shown) whose axis of revolution is transverse.

  In this way, the contact does not occur on the entire surface of the sloped hold

  but only by a generator of the roller.

  In order to facilitate the sliding of these sloping wedges, these can be covered with a coating layer with a low coefficient of

  friction such as for example polytetrafluoroethylene.

  Regarding the means (18, 19) arranged at the rear of the platform, they are identical in design to those mounted at the front of the platform, including the orientation of the slopes, directed to the

down and forward.

  The operation of this device is as follows.

  When the skier is in a straight line, and no particular impetus is exerted by the skier, other than his weight, the device

  intermediate is in the form illustrated in FIG.

  As already said, at the initiation of the turn, the skier tends to exert a localized vertical thrust (Fav) in front of the medial zone (7) of the shoe (see Figure 2). This thrust (Fav) exerted forward of the hinge point (8) of the platform (2) naturally causes the inclination of the latter to the front. In this way,

  cam surfaces (15, 17) tend to slide, and

  Given the orientation of their slope, the wedge (14) secured to the platform (2) is found before that (16) mounted on the ski (1). In this way, the relative approximation, typically of the order of two millimeters, of this wedge (16) with respect to the hinge panel (9) causes the bending of the ski so a slight rise of the front portion (20) ski. In this way, the contact area of the ski with the snow is reduced, which allows a better pivoting thereof and a setting in action in the turns

faster.

  In other words, a relatively steep ski is "softened".

  In contrast, Figure 3 shows what happens during a vertical pulse (Far) located at the rear, observed at the end of the turn. This pulse (Far) causes the pivoting of the platform (2) and its inclination towards the rear. This inclination causes the sliding of the rear cam surfaces (18, 19) and the substantial spacing of the sloping wedge secured to the ski (19) relative to the chappe (9) articulation. This spacing results in the pulling of the back of the pad area resulting in an increase in its stiffness or a slight bending down. Thus, the ski behaves as if it had a length

  superior which promotes the driving and the end of the turn.

Example 2

  The variant embodiment illustrated in FIGS. 4 to 6 operates according to

  another form of transmission of efforts.

  Thus, the rigid platform (2) receiving the attachment is also articulated on a chappe (9) integral with the upper face (10) of the ski. The rear part (12) of the platform has a rigid extension (30)

  whose rear end (31) is fixed on the upper face (10) of the ski.

  This extension (30) may be directly the rear part of the platform or may be constituted by an angled steel blade or

  aluminum alloy of high rigidity.

  The operation of this device is as follows.

  When a vertical pulse (Fav) exerted forward, the platform (2) tends to tilt forward, and its rear end (12) tends to deviate from the board (1) . This constant spacing relative to the ski by the rear extension (30) of the platform (2). This inclination thus causes the upright of the rear part (21) of the ski and thus an upward bending thereof. In this way, and as already said, the effective area of contact with the snow is reduced during the

  triggering the turn, which facilitates his behavior.

  In contrast, during the terminal phases of the turn, the vertical pulses (Far) located towards the rear cause the inclination of the platform (2) to the rear. In this way, the hatch (9) and the extension (30) of the platform transmit this pulse (Far). This results in a pressurization of the back of the pad area, or even a slight bending of the ski down. All this contributes to increase the stiffness and the sensation of length of the ski during the driving phase and the end of the turn.

Example 3

  The embodiment variant shown in FIGS. 7 and 8 concerns a platform (40) whose front portion (41) is cantilevered by

report to the board.

  This arrangement can be realized, as illustrated, by the interposition of a rigid or semi-rigid plate (42) between the rear part (43) of the platform and the upper face (10) of the ski, but could also be by two (or more) wedges interposed between the platform and the upper face of the ski, distributed behind the median zone of the

shoe (not shown).

  The characteristic plate (42) or shims not shown can

  advantageously be integrated into the platform (40).

  Thus, when the skier exerts a vertical thrust towards the front of the boot, the front end (41) cantilevered platform tends to get closer (é2 <e 1) of the upper face of the ski , and correspondingly, the rear portion of the platform tends to pivot around the front edge (45) of the plate (42), located in the vicinity of the area

  median of the shoe, which causes the bending of the ski upwards.

  It follows from the foregoing that the intermediate device according to the invention makes it possible to modify in a differentiated manner, the stiffness of the ski as a function of the location of the vertical thrusts exerted by the skier during a turn. It follows that the skis and more generally the gliding boards, equipped with such devices behave like skis of short length and soft at the initiation of the turn and vice versa as the skis of stiffness stronger and longer in phases of driving and ending the turn. These dynamic modifications of the mechanical characteristics of the ski

  constitute the main advantage of the invention.

2742343

Claims (9)

  1 / Gliding board (1) having a lower sliding surface and an upper face (10) intended to receive a safety fastening (4, 5) adapted to secure the shoe (6) of the user to the board (1). ), the board (1) being equipped at the fasteners with a stiffening device intended to modify the stiffness of the board under the effect of a thrust exerted by the user towards the upper face (10) of the board, characterized in that the stiffening device comprises: - an elongate upper platform (2) intended to receive the fastener (4, 5) on its upper face (3), said platform (2) being raised with respect to the upper face ( 10) of the board and positioned cantilevered above it; at least one connection point (8, 45) of the platform (2) with the upper face (10) of the board; means (14-19, 30, 31, 42-45) for modifying the stiffness of the board in a differentiated manner as a function of the position, with respect to said point of connection, of the point of application of the thrust (Fav , Far)   exerted by the user on the platform (2).   2 / gliding board according to claim 1, characterized in that the point of connection of the platform (2) with the board (1) is situated substantially at the level of the central zone (7) of the shoe (6), in Pivot shape (8) for articulation allowing longitudinal inclination   platform (2) in relation to the board.   3 / gliding board according to claims 1 and 2, characterized in that   that the means (18, 19) for modifying the stiffness of the board are partly located at the rear of the platform and are able to band the   ski area located between the hinge pin (8) and said means.   4 / gliding board according to claims 1 and 2, characterized in that   that the means (14-17) intended to modify the stiffness of the board are partly located at the front of the platform and are able to facilitate the bending of the ski area located between the hinge pin (8) and said means.   Gliding board according to claims 3 and 4, characterized in that   that the means for modifying the stiffness of the board are located at the rear and at the front of the platform and are respectively able to band the area of the ski located at the rear of the pivot pin and to facilitate   the bending of the ski area located at the front of the hinge pin.   6 / gliding board according to one of claims 2 or 3, characterized   in that the means consist of two opposing cam surfaces (14-19) implanted respectively under the platform (2) and on the upper face (10) of the ski, at least one of the cam surfaces being constituted by a sloped wedge (15, 17, 18, 19) whose orientation is directed forward and downward.   7 / gliding board according to claim 6, characterized in that one of the cam surfaces is constituted by a cylindrical roller whose axis of revolution is parallel to the axis of articulation (8) of the board and the platform. 8 / Gliding board according to claim 2, characterized in that the means for modifying the stiffness of the board are constituted by a fulcrum (31) of the rear (12) of the platform (2) on the top of the board.   9 / gliding board according to claim 8, characterized in that the fulcrum consists of a plate (30) forming a rear extension of the platform (2), the rear end (31) of the plate being   secured to the upper face (10) of the ski.   Gliding board according to claim 8, characterized in that the   point of support is in solidarity with the songs of the ski.   11 / gliding board according to claim 1, characterized in that the connection between the platform (2) and the upper face (10) of the board is formed by an interposed plate (42) between the platform (43) and the face top of the board, its front edge (45) being located at the rear of the board   level of the median zone (7) of the shoe (6).   12 / gliding board according to claim 11, characterized in that the interposed plate (42) is viscoelastic material with a hardness of 80 Shore A minimum.