EP1120137B1 - Alpine ski - Google Patents

Abstract

Alpine ski (1) which can be broken down over its length into a tip area (2), a binding area (3) and a heel area (4), in which the side line is such that the binding area (3) has a minimum width level (LP), the tip area (2) has a front maximum width level (LS), and the heel area (4) has a rear maximum width level (LT), characterized in that:the radius of the side line, calculated on the basis of three points (5, 6, 7) on the side line, respectively a first point (5) located at the front maximum width level (LS), a second point (7) located at the rear maximum width level (LT), and a third point (6) located centrally between the levels (LS, LT), is between 7 and 21 meters;the pressure distribution along the side line is such that, when the ski is placed on a flat surface (20) so that its underside (22) forms an angle (alpha) of 45° with the flat surface (20), and when the ski receives, at the location of the center of the boot, a force (F5) of 400 Newtons perpendicularly to its underside (22), the pressures measured along the side line differ by less than 10% from the average value of the three pressures measured respectively at the rear maximum width level (LT), at the minimum width level (LP) and at the front maximum width level (LS).

Description

Technical area

The invention relates to the field of sliding sports, and more specifically to that of alpine skiing. It relates to a small ski board geometry, which nevertheless proves particularly manageable while maintaining a behavior substantially equivalent to that of a traditional ski size.

Previous techniques

In the traditional way, the optimal length of a ski is determined according to the size of the user, its weight, and its technical level.

Thus, at present, it is considered that a ski must have a length substantially between 10 and 20 centimeters more than the size of the user.

Indeed, the longer a ski is, the more it tends to stay in the path, and allow a precise driving. On the other hand, the shorter a ski, the more flutter phenomena are observed, especially when skiing at high speed.

Nevertheless, the lengthening of the skis decreases their maneuverability, and requires more effort on the part of the skier especially in the phase of driving turns.

Thus, we know that the question of the size of a ski must allow to obtain a compromise between maneuverability and precision of the pipe.

Many evolutions in the geometry and the determination of the lengths of the skis have already been proposed, without allowing to arrive at optimal solutions.

Thus, it has already been proposed, in a range of skis called "compact skis", to greatly reduce the size of a ski, about 20 centimeters compared to the traditional size, and to widen the spatula. Such skis were intended to be used by intermediate level skiers to enable a versatile ski. These skis were fairly easy to ski but relatively inefficient.

Document FR 2 559 673 also proposed other developments in the field of skiing, notably consisting in digging very strongly the sidecut to allow a practice of cut corners. This practice requires a very good physical condition. Such skis are therefore relatively easy to ski, unstable in direct trace, skis flat, and are not versatile.

Another parameter involved in the design of a ski is its flexural stiffness. This stiffness makes it possible to distribute the weight of the skier on the snow. It is defined more or less empirically by the ski manufacturers so that, the ski being laid flat, the maximum load is under the feet of the skier, this load decreasing towards the ends of the ski.

• ◆ une réduction de la longueur peut générer une diminution du poids, donc de la stabilité du ski mais aussi une diminution de l'inertie, favorisant sa maniabilité ;
• ◆ un faible rayon de ligne de cotes a pour conséquence d'augmenter la masse des extrémités du ski, donc d'augmenter son inertie mais aussi de perturber la stabilité du ski lorsqu'il est à plat sur la neige.

These different parameters are involved in the development of a ski with the most often antinomic consequences. Therefore :

• ◆ a reduction of the length can generate a reduction of the weight, therefore of the stability of the ski but also a decrease of the inertia, favoring its maneuverability;
• ◆ a small radius of dimension line has the effect of increasing the mass of the ends of the ski, thus increasing its inertia but also to disturb the stability of the ski when it is flat on the snow.

It has been sought, in particular in document US Pat. No. 5,603,522, to determine the bearing surface of the ski with respect to its moment of polar inertia to improve its handling by reducing the forces required to trigger turns. The bearing surface is a parameter that intervenes only when the ski is flat. However, during a turn, a ski is resting on its line of edges, so that this document does not provide any useful teaching to improve the behavior during cornering.

One of the objectives of the invention is to provide a shorter ski than the skis traditionally used for a given user size, which allows a good precision in driving by the effective transmission of the forces exerted by the skier over the entire length of the ski. the odds line.

By line of dimensions or line of edges, we mean the curve defined by the edge of the edge from one end to the other of the ski. It is generally measured by determining the distance variation of the edge of the edge relative to the median longitudinal plane of the ski.

Presentation of the invention

The invention therefore relates to an alpine ski which is broken down along its length into a spatula zone, a skate zone, and a heel zone, and whose dimension line is such that the skate zone has a minimum width level, the spatula zone. has a maximum front width level, and the heel area has a maximum rear width level.

An alpine ski in accordance with the invention is characterized by the combination of several dimensional mechanical parameters which thus make it possible to have the same behavior as traditional skis of about twenty centimeters longer, but thus improving its maneuverability.

Thus, in accordance with the invention, the radius of the dimension line, calculated from three points of the dimension line located respectively at the maximum rear width level, at the maximum front width level, and in the middle of these two levels. , is between 7 and 21 meters.

In addition, the pressure distribution on the edge is one of the paramount factors in the proper functioning of a ski, that is to say in its ability to fit into a curve and to maintain its trajectory without skidding or chattering. .

Indeed, the ski according to the invention has a distribution of the pressure of the edges along the line of dimensions, such that when the ski is disposed on a flat surface, so that its sole forms an angle of 45 With said flat surface, and that the ski receives at the level of the middle of the shoe a force of 400 Newton perpendicular to its gliding surface, the pressures measured along the dimension line differ by less than 10% from the average value. the three pressures measured respectively at the maximum rear width level, at the minimum width level of the pad, and at the maximum front width level.

In other words, thanks to the ski according to the invention, the forces exerted by the skier, especially when he executes the turn, are very regularly and almost uniformly distributed along the line of edges, which ensures an optimal driving of the turn .

Indeed, the skis of the prior art have a pressure distribution on the edge line which is such that the majority of efforts are transmitted to the level of the skate zone, and more precisely to the foot of the shoe, while that the front and rear areas of the board transmit a very small part of efforts.

This stiffness adjustment is obtained correctly, either by adding reinforcements in the appropriate areas, or by adjusting the thickness of the ski so as to vary the distance of the reinforcements relative to the neutral fiber.

Advantageously in practice, the distribution of pressures along the edge line is such that the pressure value measured at the level of the maximum width of the bead is slightly greater than the pressure value measured at the level of the maximum width of the spatula.

In other words, the efforts exerted by the skier during the turn are distributed almost uniformly between the front and the back of the ski, because during the turn, the effort exerted by the skier is positioned in front of the middle of the shoe, this which compensates for the characteristic pressure distribution determined with a static load located exactly at the level of the middle of the shoe.

It has been observed that the behavior of the ski is very favorable when the pressure value measured at the level of the maximum width of the bead is approximately 10% higher than the pressure value measured at the maximum width level of the spatula.

In addition, the skis according to the invention are of smaller size than traditional skis. However, they are not equivalent to classic but shorter skis, ie skis used normally or by small people. size or even by children, or by people of low weight or low muscle mass.

Indeed, the ski according to the invention must be stiffer in bending to withstand heavy loads and more powerful pulses.

• ■ d'une distance comprise entre 60 et 70 millimètres lorsque les appuis sont situés respectivement à la ligne de contact arrière et à 5/18^ème de la longueur portante à compter de la ligne de contact arrière;
• ■ d'une distance comprise entre 50 et 60 millimètres lorsque les appuis sont situés respectivement à 5/18^ème de la longueur portante à compter de la ligne de contact arrière et à 13/18^ème de la longueur portante à compter de la ligne de contact arrière;
• ■ d'une distance comprise 65 et 75 millimètres lorsque les appuis sont situés respectivement à la ligne de contact avant et au 5/18^ème de la longueur portante à compter de la ligne de contact avant.

Thus, it has been determined that considering the load-bearing length of the ski defined between the front contact lines and the rear contact lines, the stiffness of the ski according to the invention is such that when the ski is placed flat between two supports and that a force of 400 Newtons is exerted perpendicularly to the upper face of the ski midway between the two supports, the point situated halfway between the two supports moves downwards with respect to the situation where the load is absent,

• ■ from a distance of between 60 and 70 millimeters when the supports are situated respectively at the rear contact line and at 5/18 ^th of the bearing length from the rear contact line;
• ■ from a distance of between 50 and 60 millimeters when the supports are situated respectively at 5/18 ^th of the bearing length starting from the rear contact line and at 13/18 ^th of the bearing length starting from the line of rear contact;
• ■ a distance of between 65 and 75 millimeters when the supports are situated respectively at the front contact line and at 5/18 ^th of the bearing length from the front contact line.

Such stiffness therefore contributes to giving the ski of shorter length behavior equivalent to that of a longer ski.

In practice, the skis according to the invention have a total length, measured between the front and rear ends of the ski of between 1300 and 1740 millimeters.

This is a range corresponding to a range of traditional skis about twenty centimeters more.

• ■ sa largeur mesurée au niveau de largeur maximale avant est comprise entre 102 et 108 millimètres;
• ■ sa largeur mesurée au niveau de largeur minimale est comprise entre 64 et 70 millimètres;
• ■ sa largeur mesurée au niveau de largeur maximale arrière est comprise entre 92 et 100 millimètres.

Advantageously in practice, the ski according to the invention has a dimension line such that:

• Its width measured at the level of maximum front width is between 102 and 108 millimeters;
• Its width measured at the minimum width level is between 64 and 70 millimeters;
• Its width measured at the maximum rear width level is between 92 and 100 millimeters.

Brief description of the figures

• La figure 1 est une vue de dessus d'un ski conforme à l'invention.
• La figure 2 est une vue schématique de côté d'un ski conforme à l'invention.
• La figure 3 est une section schématique d'un ski conforme à l'invention, montré lors du test de mesure de la répartition de pression sur de la ligne de carres.
• La figure 4 est un diagramme illustrant la variation de pression le long de la ligne de cote au ski conforme à l'invention.
• La figure 5 est un diagramme équivalent, correspondant à un ski de l'Art antérieur.

The manner of carrying out the invention as well as the advantages which result therefrom will emerge from the description of the embodiments which follow, in support of the appended figures in which:

• Figure 1 is a top view of a ski according to the invention.
• Figure 2 is a schematic side view of a ski according to the invention.
• Figure 3 is a schematic section of a ski according to the invention, shown in the test of measurement of the pressure distribution on the edge line.
• Figure 4 is a diagram illustrating the pressure variation along the side line to the ski according to the invention.
• Figure 5 is an equivalent diagram, corresponding to a ski of the prior art.

Way of realizing the invention

As already mentioned, the invention relates to an alpine ski whose geometry and stiffness distribution are distinguished from the prior art to give a ski of short length, the behavior of a traditional ski of much greater length.

Such a configuration therefore makes it possible to very significantly improve the handling of the ski in use as well as the off-use handling operations.

As already stated, the ski according to the invention is characterized by a number of dimensional and mechanical parameters which, combined, make it possible to optimize the behavior of the ski.

Thus, the skis according to the invention have sizes well below the sizes usually used by skiers of equivalent level. Thus, a size correspondence table is reproduced below in which the first column corresponds to the sizes in centimeters of traditional skis, and the second column corresponds to the size of skis according to the corresponding invention. Traditional ski size Ski size according to the invention 195 174 184-191 167 184-177 160 177-160 150 160 140 150 130

Thus, it is found that the skis according to the invention have a size between 10 and 20 centimeters lower than traditional skis, while they have the same behavior, which suggests significant gains in handling and space.

Thus, as illustrated in Figure 1, a ski (1) according to the invention has a spatula (2) whose maximum width (Ls) is between 102 and 108 millimeters, the shoe (3) has a minimum width (Lp) between 64 and 70 millimeters, while the heel (4) has a maximum width (Lt) of between 92 and 100 millimeters.

In a particular example of a ski of size 167 centimeters, the spatula has a maximum width of 103 millimeters, the slider a minimum width of 65 millimeters and the heel a maximum width of 93 millimeters.

As the skis according to the invention have a shorter length than traditional skis, they have on the other hand an increased width, in particular spatula and heel, to present an equivalent load bearing surface.

The measurement of the load bearing surface of a ski according to the invention of size 167 cm is 0.108 m ² to be compared with the 0.114 m ² of a traditional ski of size 191 cm with equivalent behavior.

The definition of a dimension line is also translated by the value of the theoretical radius passing through three points (5, 6, 7) of the line of dimensions situated respectively, as illustrated in FIG. 1. The first point (5) is located at the maximum width level of the spatula (2). The second point (7) is at the level of maximum width of the heel (4). The third point (6) is located on the dimension line equidistant from the other two points (5, 7) of maximum width.

The ski whose particular parameters are defined above has a theoretical radius of curvature equal to 16.4 meters, compared to the theoretical radius of curvature of a corresponding traditional ski, close to 30 meters.

Of course, the invention is not limited to this single dimension line radius value, but covers the various variants in which the dimension line radius is between 7 and 21 meters.

Moreover, to obtain the desired behavior, the ski according to the invention must have an increased stiffness compared to the equivalent ski of greater size, to withstand on the one hand to higher loads, and on the other hand, to pulses more powerful.

In practice, the stiffnesses are measured as follows (see Figure 2).

The ski is placed flat between two supports, and receives a load (F ₂ , F ₃ , F ₄ ) of 40 kg, corresponding to half the weight of a skier of 80 kg. This load of 40 kg is applied equidistant from the two supports.

The measurement of the arrow in millimeters, corresponding to the vertical displacement of the point of application of the load, reflects the stiffness of the measured portion of the ski.

Three measurements are made, respectively at the heel (4), the pad (3) and the spatula (2).

The stiffness of these different zones is determined by positioning the different supports at precise positions.

First of all, it is necessary to determine the load bearing length (L _PORT ) of the ski, measured between the two lines of contact before (L _CAV ) and rear (L _CAR ), defined in a standardized way.

For the measurement of the stiffness of the heel (4), a first support (10) is arranged at the level of the rear contact line (L _CAR ) the other support (11) being arranged further forward, at a distance equal to 5/18 ^th of the bearing length (L _PORT ).

To measure the stiffness of the shoe area (3), a first support (11) is arranged at 5/18 ^th of the bearing length, starting from the rear contact line (L _CAR ).

The second support (12) is disposed in front of this first support (11) at a distance equal to 4/9 ^th of the bearing length (L _PORT ).

For the measurement of the stiffness in the spatula zone (2), the front support (12) of the measurement of the stiffness in zone skid is preserved, the second support (13) then being arranged at the level of the line of contact before (L _CAV ).

These two supports are deductively separated by a distance equal to 5/18 ^th of the bearing length.

In practice, for a ski of size 167 centimeters, having a bearing length of 1 435 millimeters, the supports are respectively disposed at the following distances counted from the rear contact line (L _CAR ) Heel area 0 and 399 millimeters Skate area 399 millimeters and 1,036 millimeters Spatula area 1,036 millimeters and 1,435 millimeters

• ◆ zone talon : 65 millimètres de déformation
• ◆ zone patin : 51 millimètres de déformation
• ◆ zone spatule : 70 millimètres de déformation.

The deformations or arrows of the different zones of the particular ski described above are as follows:

• ◆ heel area: 65 millimeters of deformation
• ◆ skate zone: 51 millimeters of deformation
• ◆ spatula zone: 70 millimeters of deformation.

It goes without saying that the invention is not limited to these stiffness determination values alone, but covers wider ranges for which the deformation in the heel zone is between 60 and 70 millimeters, the deformation in the skid zone is between 50 and 60 millimeters, and the deformation in spatula zone is between 65 and 75 millimeters.

It should be noted that for a traditional ski of behavior identical to the aforementioned ski, the deformations in heel and spatula are respectively 94 and 92 millimeters, reflecting a significantly lower stiffness.

Furthermore, another mechanical parameter of the ski according to the invention relates to the distribution of pressure on the edge which is particularly constant, in comparison with the distribution measured on a traditional ski, which is clearly irregular with a maximum pressure of pressure. measured at the skate zone.

Thus, to measure this parameter, the ski (1) is placed on a test table equipped with pressure sensors arranged at regular intervals, each spaced apart by 8 millimeters.

The ski is disposed on this test table (20) in such a way that its sole (22) forms an angle (α) of 45 ° with respect to the test table (20), as illustrated in FIG.

The ski receives a force (F ₅ ) exerted by a suitable apparatus, with an intensity of 400 Newtons, corresponding substantially to half the weight of a skier of 80 kg, this force being exerted perpendicular to the surface (22) of slip from the ski.

Under the load, the ski is deformed until the edge of the edge (23) comes over its entire bearing length, in contact with the test table (20), which therefore allows via the gauges (21) to measure the pressure at each point of the line of dimensions, at an interval of the order of 8 millimeters.

It should be noted that, before the application of the load, the ski rests diagonally on its two points of maximum width, spatula and heel. Then, under load, the ski gets hanger, that is to say that the pad area descends below its end zones until it comes to press on the measurement table. Depending on the shape of the dimension line and the specific stiffnesses of each zone, the force sensors (21) measure the applied pressure.

The result is illustrated in FIG. 4, in which the variation of the pressure is observed along the entire length of the dimension line.

The measurement given in ordinate is a value of pressure whereas the abscissa represents the length of the ski. To account for distributions measured on skis of different sizes, the pressure value is not calibrated, but corresponds to relative levels.

These values deviate by less than 10% from the mean value of the pressure, which corresponds to a quasi uniformity of the pressure along the dimension line. It is thus observed that the pressures measured along the entire length of the dimension line vary between a minimum value and a maximum value whose difference corresponds to at most 20% of the average value.

In practice, it has been observed that the behavior was optimal when the pressure value measured at the rear of the ski was greater by about 10% compared to the pressure measured at the front of the ski.

By way of comparison, FIG. 5 illustrates the distribution of the pressure measured according to the same technique on a traditional ski of size 191 centimeters, corresponding in behavior to that of the ski of size 167 according to the invention.

It is very clearly observed that most of the pressure is transmitted at the level of the skid zone, and much more lightly at the level of the front and rear contact lines, the pressure in the intermediate zones respectively in front of the rear contact line. and behind the front contact line being extremely reduced, and less than one-third of the maximum pressure measured at the pad area.

Thanks to a pressure distribution according to the invention, when the skier conducts his turn, the entire edge exerts a pressure substantially identical on the snow, which results in a very good registration in the turn and facilitated driving of it.

It follows from the foregoing that the combination of the different dimensional and mechanical parameters of the ski according to the invention allows the ski to exhibit a behavior identical to that of a ski of length about 20 centimeters higher while improving the maneuverability and ease turn initiation.

In addition, the skis according to the invention being shorter, they are much easier to store and transport.

Claims (6)

1. Alpine ski (1) which can be broken down over its length into a tip area (2), a binding area (3) and a heel area (4), in which the side line is such that the binding area (3) has a minimum width level (Lp), the tip area (2) has a front maximum width level (L_S), and the heel area (4) has a rear maximum width level (L_T), having the radius of its side line, calculated on the basis of three points (5,6,7) on the side line, respectively a first point (5) located at the front maximum width level (L_S), a second point (7) located at the rear maximum width level (L_T), and a third point (6) located centrally between the said levels (L_S,L_T), which is between 7 and 21 metres; characterized in that the pressure distribution along the side line is such that, when the ski is placed on a flat surface (20) so that its underside (22) forms an angle (α) of 45° with the said flat surface (20), and when the ski receives, at the location of the centre of the boot, a force (F₅) of 400 Newtons perpendicularly to its underside (22), the pressures measured along the side line differ by less than 10% from the average value of the three pressures measured respectively at the rear maximum width level (L_T), at the minimum width level (L_P) and at the front maximum width level (L_S).
2. Ski according to Claim 1, characterized in that the pressure distribution along the side line is such that, when the ski is placed on a flat surface (20) so that its underside (22) forms an angle (α) of 45° with the said flat surface (20), and when the ski receives a force (F₅) of 400 Newtons perpendicularly to its underside, the pressure value measured at the location of the rear maximum width (L_T) is greater than the pressure value measured at the location of the front maximum width (L_S).
3. Ski according to Claim 2, characterized in that the pressure distribution along the side line is such that, when the ski is placed on a flat surface (20) so that its underside (22) forms an angle (α) of 45° with the said flat surface (20), and when the ski receives a force (F₅) of 400 Newtons perpendicularly to its underside, the pressure value measured at the location of the rear maximum width (L_T) is greater by at least 10% than the pressure value measured at the location of the front maximum width (L_S).
4. Ski according to Claim 1, having a front contact line (L_CAV) and a rear contact line (L_CAR) which are separated by the load-bearing length (L_PORT) of the ski, characterized in that its stiffness is such that, when the ski is placed flat between two supports (10,11,12,13), and when a force (F₂, F₃, F₄) of 400 Newtons is exerted perpendicularly to the upper face of the ski midway between the two supports, the point located midway between the two supports is displaced downwards with respect to the situation in which the load is absent

   ■ by a distance of between 60 and 70 millimetres when the supports (10,11) are located respectively at the rear contact line (L_CAR) and at 5/18^ths of the length (L_PORT) measuring from the rear contact line (L_CAR) ;

   ■ by a distance of between 50 and 60 millimetres when the supports (11,12) are located respectively at 5/18 ^ths of the load-bearing length (L_PORT) measuring from the rear contact line (L_CAR) and at 13/18^ths of the load-bearing length (L_PORT) measuring from the rear contact line (L_CAR);

   ■ by a distance of between 65 and 75 millimetres when the supports (12,13) are located respectively at the front contact line and at 5/18^ths of the load-bearing length measuring from the front contact line (L_CAV).
5. Ski according to Claim 1, characterized in that its total length L measured between the front and rear ends of the ski is between 1 300 and 1 740 millimetres.
6. Ski according to Claim 1, characterized in that:

   ■ its width measured at the front maximum width level L_S is between 102 and 108 millimetres;

   ■ tits length measured at the minimum width level L_P is between 64 and 70 millimetres;

   ■ its width measured at the rear maximum width level L_T is between 92 and 100 millimetres.

Images