FR2700477A1 - Cross country ski with varying width - Google Patents

Abstract

The ski has its maximum width (P1) between its front contact line (5) and the sliding surface. The ratio of the distance (D) between this point and the contact line to the distance between the front and back contact points is at most equal to 8.5%.The width of the ski tapers near the back (7) and a zone, with a constant width, extends from this to the sliding surface. The next zone (9) widens as far as the widest point. Between this point and the front contact point (10), the width decreases and the front zone (11) is triangular.

Description

CROSS-COUNTRY SKIING
The invention relates to a cross-country ski intended for both experienced and novice skiers.

 it is also more particularly suited to the technique known as the skater's step, although it can also be used by the more traditional technique known as the alternative step.

 In a known manner, the technique of the skater's step, better known under the expression in English "skating", consists of evolving by making his skis diverge from the direction of progression, the propulsion proper being ensured by exercise alternating transverse pulses by the skier on one of his skis.

This technique essentially breaks down into four successive phases, respectively a first phase where the ski is in external support, followed by a flat gliding phase, followed in turn by a pulse phase on the internal face of the ski, and finally by a phase called "flight", during which the ski leaves the snow until the next movement is pressed. In other words, this technique consists in ensuring progression not by the exercise of a thrust in the longitudinal direction, but on the contrary by means of successive and alternating transverse supports.

 Skating ski therefore requires high lateral flexural and torsional strength characteristics, but also involves achieving a balance within it, in order to allow its efficient handling, taking into account its path during progression both longitudinal, then transverse, and its "flight", during the last stage of progression.

 The skating skis available today certainly allow to reach a reasonable compromise, but however not satisfactory at least in terms of handling. Indeed, it is not uncommon to observe with these skis a relative difficulty of handling inherent in the technique of skating, but also in their very design, handling which results in particular in the difficulty to bring back the ski during the phase of theft, affecting the efficiency and effectiveness of this technique.

 The other known technique, namely the alternating step, consists in launching each ski alternately forward in two parallel rails provided for this purpose on the track. The ski used for the practice of this technique has a central arched part, in particular at the level of the skate, comprising a means capable of allowing the temporary grip of the ski when it is in contact with snow, this means being able to be constituted either a wax chamber, either by scales formed on the sole, or even a skin system fixed in particular by gluing on said sole. In the context of this technique, it is now well known to use skis with parallel edges and a narrow tip, given the ease of sliding which they exhibit in the guide tracks provided in snow, compared to skis with a curved dimension line.

 Indeed, with this particular dimension line, there is a decrease in the resistance opposed by said guide tracks on the ski during progression. On the other hand, such a ski as currently produced is not entirely satisfactory for this technique, once again taking into account its lack of maneuverability, although the latter remains permanently aligned with the direction of progression.

 The object of the invention is to provide a cross-country ski, capable of possibly being used for the so-called alternative pitch technique, but especially for that known as skating, having great maneuverability in order to optimize the performance achieved in a technical as in the other.

 This cross-country ski comprising a zone of maximum width situated between the shoe and the front contact line is characterized in that the ratio of the distance D separating this zone and the said front contact line to the bearing length of the ski, defined as being equal to the developed length of the sole separating the two contact lines respectively front and rear of the ski, is at most equal to 8.5%, this distance D never being equal to zero.

 If it was certainly known to make cross-country skis whose widest point does not coincide with the front contact line at the level of the tip, however, it was not known to reduce the distance separating these two zones and correlate it to the bearing length of the ski.

We have in fact realized that by applying this ratio, we end up with skis of great maneuverability, regardless of their developed length or their carrying length, without altering their other desired characteristics, such as for example rigidity etc ...

The invention therefore consists in shortening a ski, not by homotety, but not truncation of its ends.

According to an advantageous characteristic of the invention, the developed and projected surface of the ski is broken down into five essential zones, namely from the heel to the tip:
- a zone comprising the heel, tapered and of increasing width;
- an area of constant width, extending the previous area and extending approximately to the area of the skate;
- an area of increasing width extending from the shoe to the area of maximum width of the ski,
- an area of decreasing width, extending from the point of maximum width to the front contact line,
- And finally, a front zone corresponding to the tip, of decreasing width and of substantially triangular shape, extending from the front contact line to the front end of the ski.

 According to a variant of the invention, the zone of maximum width extends over a distance of a few centimeters.

 Finally, according to another characteristic of the invention, the ratio of the bearing surface, defined as being the developed surface of the ski at the level of its sole between the two front and rear contact lines related to the bearing length is at least equal to 45, expressed in units of length, and corresponding to the fictitious width that a rectangular ski would have.

 The manner in which the invention can be implemented and the advantages which ensue therefrom will emerge more clearly from the following exemplary embodiments, given by way of indication and without limitation in support of the appended figures.

 Figure 1 is a side view of a ski according to the invention.

 Figures 2 and 3 are schematic representations of the developed surface projected in accordance with the invention, according to two different embodiments.

 Traditionally and as shown in FIG. 1, a cross-country ski (1) comprises a tip (3), extending in front of the front contact line (5), and directed upwards, and a heel (2), starting from the rear contact line (6), and being slightly directed upwards, thus constituting the heel lift.

 By front and rear contact line, we traditionally mean all of the points of the ski sole, respectively in the anterior zone and in the posterior zone coming into contact with a flat surface on which the ski rests in the absence of any other load. than that generated by its own mass, these two sets, taking into account the flatness of the sole in these zones defining a line.

 The central zone of the ski or skate (4) has a camber or arrow, so that in the absence of a load placed on the ski other than that inherent in its own mass, the sole of the skate (4) is not in contact with the soil referenced by the letter P.

 The bearing length of the ski, Lp, is defined between the two contact lines respectively front (5) and rear (6). According to the invention, this ski has a point or a zone of greater width, defined by the reference PI, and located between the shoe (4) and the front contact line (5), and in general much closer to the latter only skating.

 In fact, and as can be seen in FIGS. 2 and 3, on either side of this area of greater width, said width of the ski effectively decreases in the direction of the front contact line ( 5) and the central ski area.

 The front of this zone of greatest width PI, is located at a distance D from the front contact line (5), such that the ratio D on the bearing length Lp of the ski is at most equal to 8.5%, without however reaching the value of zero.

 The use of the term distance for D must be understood in its universally known geometric meaning. In the context of the invention, this distance D separates the front contact line (5) from the line of greatest width PI of the ski (FIG. 2), or from the front edge of the area of greatest width (12) from the ski (Figure 3).

According to another characteristic of the invention, which can be better perceived in connection with FIGS. 2 and 3, the developed surface of the ski comprises five zones referenced (7) to (11), as defined below:
- The area (7), integrating the heel, is tapered towards the end, and its width increases from said end. Its length is 50 + 20 mm and its maximum width at its junction with the consecutive zone (8) is 47 + 3 mm;
- the area (8) is an area with parallel edges, and is therefore rectangular, of constant width equal to 47 + 3 mm, extending over a length of 400 + 100 mm, up to substantially at the level of the pad area ( 4);
- the immediately consecutive zone (9) is also of increasing width, up to a value of 49 + 5 mm, at the level of the widest zone of the ski, or of the PI. Its length is 800 + 200 mm;
- The next area (10) has a decreasing width towards the end of the front contact line (5) from 49 + 5 to 48 + 5 mm. As defined above, its length is at most equal to 8.5% of the bearing length Lp, without ever reaching the value zero;
- And finally the area (11) is also an area of decreasing width and corresponding to the spatula proper and of substantially triangular shape.

 In another embodiment of the invention shown in FIG. 3, the area of greatest width (12) may have a certain length, typically varying from 0 to about ten centimeters, either in the direction of the pad (4), either towards the front contact line (5).

 Be that as it may, the distance D separating the front edge of this zone (12) from the front contact line (5) remains at most equal to 8.5% of the bearing length Lp. This data is decisive for obtaining the desired characteristics of the ski according to the invention.

 According to another characteristic of the invention, the ratio of the bearing surface, that is to say the developed surface of the sole of the ski corresponding to the bearing length Lp, expressed in mm2 relative to said bearing length, expressed in mm, is greater than or equal to 45, expressed in mm, and corresponding to the fictitious width that a rectangular ski would have.

 In addition, and advantageously, the zone (7) comprising the heel has a developed length advantageously less than 100 mm.

 All of these characteristics give the ski greater maneuverability, which is particularly sought after in the skating technique, but also advantageous in the technique known as skating step.

Claims (6)

 1 / Cross-country skiing comprising a zone of maximum width PI situated between the shoe (4) and the front contact line (5) characterized in that the ratio of the distance D separating this zone PI and the said front contact line ( 5) the carrying length of the ski Lp, defined as being equal to the developed length of the sole separating the two contact lines respectively before (5) and rear (6) of the ski, is at most equal to 8.5%, this distance D is never zero.  2 / Cross-country skiing according to claim I, characterized in that the developed and projected surface of the ski is broken down into five essential zones, namely from the heel (2) to the tip (3):  - a zone (7) comprising the heel, tapered and of increasing width, extending from the rear end of the ski;  - an area of constant width (8), extending the previous area and extending substantially to the area of the shoe (4);  - an area (9) of increasing width extending from the shoe (4) to the area of maximum width PI of the ski,  - an area (10) of decreasing width, extending from the area of maximum width PI to the front contact line (5),  - And finally, a front zone (11) corresponding to the tip, of decreasing width and of substantially triangular shape, extending from the front contact line to the front end of the ski.  3 / Cross-country skiing according to claim 2, characterized in that:  - the length of the area including the heel (7) is 50 + 20 mm and its maximum width is 47 + 3 mm;  - The width of the zone (8) is constant and equal to 47 + 3 mm, said zone extending over a length of 400 + 100 mm, until substantially at the level of the zone of the pad (4);  - The width of the zone (9) increases to a value equal to 49 + 5 mm at the level of the widest zone (12) of the ski, or of the PI, its length being 800 + 200 mm;  - the width of the zone (10) decreases up to the front contact line (5) where the width is 48 + 5 mm, the length D of this zone being at most equal to 8.5% of the bearing length Ski lp.  4 / Cross-country skiing according to one of claims 1 to 3, characterized in that the maximum width zone (PI - 12) extends over a distance of a few centimeters.  5 / Cross-country ski according to one of claims 1 to 4, characterized in that the ratio of the bearing surface, defined as being the developed surface of the ski at the level of its sole between the two lines of front contad (5) and rear (6) at the bearing length Lp is at least equal to 45, expressed in units of length.  6 / Cross-country skiing according to one of claims 1 to 5, characterized in that the zone (7) comprising the heel has a developed length of less than 100 mm.