Patent Application
20080116662
This application claims priority under 35 U.S.C. §119 of French Patent Application No. 06 10280, filed on Nov. 22, 2006, the disclosure of which is hereby incorporated by reference thereto in its entirety.
1. Field of the Invention
The present invention relates to snow gliding skis.
2. Description of Background and Other Information
To be usable on different types of snow, a ski generally has a substantial length, on the one hand, and a variable width, on the other hand, the central zone being generally narrower than the end zones.
When a skier skis on powder snow with skis primarily designed for use on packed snow, he is forced to modify his manner of skiing, especially his body position. An efficient and safe technique requires a forward position, whereby the skier is said to be “engaging the slope”. However, when the skier is on powder snow, he must move his body rearwardly to prevent the front of the skis from digging too much into the snow.
In order to improve their use on powder snow, certain areas of the skis have been proposed to be widened and the length of the shovel, at the front of the ski, has been proposed to be increased, shovel length being defined in the direction of the length of the ski between the front end of the ski and the front contact line, namely, the contact line which the ski would have when placed on a planar, or flat, surface.
The document FR 2 786 108 discloses such a ski in which the front and rear contact lines are closer to the boot than they are in a conventional ski. In addition, the shovel of such ski is significantly raised, the profile of the shovel being made of a succession of portions that all have radii of curvature less than 3 meters (m). The use of such a ski on powder snow is thereby enhanced, although the use of such a ski on packed snow is made much more difficult. Furthermore, in such a ski, the succession of shovel portions, each of which has a radius of curvature that is different but close in value to that of adjacent portions, causes the visual perception of the shovel to be reduced. However, it has been noted that the visual perception of the shovel, i.e., a raised area at the front of the ski, is a psychological factor which inspires confidence in the skier. Indeed, one can understand that the skier will not fear being stopped or destabilized by a low obstacle if he knows that the ski has a raised shovel.
Furthermore, in cases where skis are made flat and then bent to form a shovel, the shovel lacks continuity because it is made by a succession of portions having a straight profile connected together by angular zones. In this case, there is no tangency between the profile of the shovel and the profile of the central portion of the ski, on the one hand, and between the profiles of the various shovel portions, on the other hand. If such a construction were to be considered as having no disadvantage for skis having modestly sized shovels, it becomes a problem in terms of stability and skiability with longer shovels. Furthermore, when a ski has a large shovel made according to the method of bending the front of the ski, the presence of more or less prominent “flat portions” can be noticed. “Flat portions” refers to each portion of the bottom surface whose profile is comparable to a straight line. To detect the presence of “flat portions”, one lays the ski on a planar surface and then lifts the tail of the ski so that the contact point between the bottom surface and the planar surface moves from the front contact line to the end of the ski. This is a rolling movement of the bottom surface on a planar surface. During this rolling movement, as soon as the contact between the bottom surface and the planar surface is no longer a mere transverse line relative to the longitudinal direction of the ski, but a surface, this surface can be regarded as a “flat portion”. The more substantial a “flat portion”, the more it negatively affects the behavior of the ski, particularly the stability of the ski.
Conversely, a ski with no “flat portion” has a better, more stable behavior with more grip. Furthermore, when one skies on powder snow, having a “flat portion” in the area of the shovel can cause the snow to accumulate in the area of this “flat portion”, which can create a blockage.
The present invention provides a ski that can overcome the limitations of known prior art devices. More particularly, the invention provides a ski whose behavior is optimal both on powder snow and on trails with packed snow.
In addition, the invention improves the ski behavior on packed snow.
The invention is directed to a ski adapted to receive a user's boot and having a front tip S, a rear end T, and a central zone located between the front tip and the rear end and which, when placed on a planar surface, comprises at least two contact lines with the planar surface, namely, the forward contact line LS located in the vicinity of the front tip, on the one hand, and the rear contact line LT located in the vicinity of the rear end, on the other hand, the distance DS separating the forward contact line LS from the ski tip S being greater than 500 mm (millimeters), i.e., DS>500 mm.
In a particular embodiment, the portion located between the front tip S and the forward contact line LS, i.e., the shovel, is made as a convex area, which includes:
a first shovel portion whose lateral profile is comprised between a circular arc having a 9-meter radius and a circular arc having a 5-meter radius;
a second shovel portion adjoining the first shovel portion and having a profile comprised between a circular arc having a 9-meter radius and a circular arc having a 1-meter radius;
a third shovel portion adjoining, or contiguous with, the second shovel portion and extending up to the front tip of the ski.
In a particular embodiment, the profile of the first and second shovel portions has no “flat portion.”
Further, according to a particular embodiment, the profile of the first and second shovel portions is such that, with any pair of points P1 and P2 placed at a 150-mm-chord distance from one another on the curve reproducing the lateral profile of the shovel, there is at least one point of the curve between P1 and P2 which is more than 0.5 mm away from the chord joining P1 to P2.
In a particular embodiment of the invention, the first shovel portion has the shape of a circular arc having a radius R1 comprised between 5 m and 9 m, and the second shovel portion has the shape of a circular arc having a radius R2 comprised between 3 m and 1 m.
In a particular embodiment of the invention, the third shovel portion has a length comprised between 80 mm and 130 mm.
In a particular embodiment, the height H, which corresponds to the distance separating the planar surface from the ski measured at a point 300 mm away from the front ski tip, is comprised between 5 mm and 25 mm, i.e., 5 mm<H<25 mm.
In an embodiment of the invention, the distance DT separating the rear contact line LT from the rear end T is less than 300 mm, i.e., DT<300 mm.
The invention will be better understood from the description that follows, with reference to the attached drawings, in which:
The ski 1 according to the invention is an elongated structure which extends from a front tip 5 to a rear end 6. The lower surface 8, or bottom surface, is generally flat and is adapted to glide on the snow. The top surface 7 is also generally flat but can have various projections or unevenness.
The central zone of the ski includes a line, i.e., the center line MC of the boot. This line corresponds to the recommended location for the middle of the boot 4 when the boot is positioned between the bindings, which are fixed on either side of the middle line MC of the boot.
The bindings, or retaining means, comprise a front abutment 2, or toe piece, positioned forward of the line MC and the rear abutment 3, or heel piece, positioned rearward of the line MC. Together, the toe and heel pieces 2, 3 retain the boot 4 on the ski.
Beyond the front contact line LS, the ski portion comprised between the front contact line LS and the front tip S is called the shovel. The shovel length DS corresponds to the distance separating the front contact line LS from the front tip S. According to the invention, this length is greater than 500 mm. In the example shown, the overall ski length L equals 1920 mm and the length DS equals 730 mm.
The substantial length of the shovel reduces the risk of having the ski dig into the snow when skiing on powder snow. However, even when skiing beyond a trail on powder snow, the skier is able to position his body forwardly and to maintain a position that is similar to his position when skiing on a packed-snow trail.
The position of the front contact line LS is such that the distance DM that separates it from the boot middle line MC is greater than 300 mm.
The ski portion positioned between the rear contact line LT and the rear end T defines what is referred to as the ski tail. In the ski of the invention, the tail is much shorter than the shovel. The rear contact line LT is positioned at a distance DT from the rear end T of the ski, which is less than 300 mm. In the example shown, this distance equals 100 mm.
The line of the width of the waist of the ski, LWP, is positioned in the vicinity of the boot middle line, set back with respect to the latter. The ski width in the area of this line is commonly called the waist width. The waist width is comprised between 100 and 150 mm, or between about 100 and about 150 mm. In the example shown, the width of the waist of the ski is 127 mm.
The line of the width of the heel of the ski, LWT, is located in the vicinity of the rear contact line LT between the latter and the rear end T of the ski. The line LWT can also be situated exactly in the area of the rear contact line LT. The ski width is measured on this line and is commonly referred to as the tail width. The tail width is comprised between 110 and 160 mm. In the example shown, the tail width equals 137 mm.
The line of the width of the shoulder of the ski, LWS, is located between the front end of the ski and the front contact line LS at a distance DWS from the latter. The distance DWS is comprised between 440 mm and 640 mm. In the example shown, it measures 540 mm. The ski width on this line is commonly referred to as the shovel width. The shovel width is comprised between 125 mm and 170 mm. In the example shown, it measures 147 mm.
When the ski is flat on the snow, the bottom edges in contact with the snow are limited to the running edges located between the rear contact line LT and the front contact line LS. When the ski is no longer flat on the snow and the skier edges, the contact length increases up to a maximum defined by the distance separating the line of the width of the ski shoulder LWS from the width of the ski heel LWT.
In the ski of the invention, the distance between the lines of maximum width is much more substantial than that between the front and rear contact lines. Due to this, as soon as the skier initiates a turn and edges, the length of the edge gripping the trail is more substantial.
For example, a lateral profile of this portion can be given a shape in the form of an arc of circle whose radius R1 is comprised between 4 m and 9 m. In this case, in the example shown, the radius R1 equals 6 m.
Choosing a circular arc shape ensures a better continuity from the central portion to the ski tip, only if the profile of the shovel is made of straight line portions. In addition, the profiles of the central portion and shovel are strictly tangent in the area of the front contact line LS.
The choice of a circular arc shape is non-limiting within the scope of the invention. Other profiles are possible, provided they fit in the space comprised between two arcs of a circle extending through the point LS and the tangent, in the area of this point, to the profile of the ski central portion. The two circular arcs are one arc of a circle with a 9-meter radius, on the one hand, and a circular arc having a 5-meter radius, on the other hand. Furthermore, reference is made to the point LS, although LS was designated hereinabove as being the front contact line. This is not a contradiction insofar as when considering the lateral profile of the ski, the line LS represents a point.
The profile of the first shovel portion 10 extends from the point LS to the intermediate point J1.
The second shovel portion 11 is contiguous and tangent to the first shovel portion 10. It has a lateral profile having a greater convexity. For example, the second shovel portion 11 can be given a lateral profile in the form of a circular arc having a radius R2 comprised between 1 m and 9 m or, in a particular embodiment, between 1 m and 3 m. In this particular case, i.e., in the example shown, the radius R2 equals 1.5 m.
For the second shovel portion 11, the choice of a circular arc shape is non-limiting within the scope of the invention. Other profiles are possible as long as they fit in the space comprised between two arcs of a circle extending through the point J1 and tangent, in the area of this point, to the profile of the first shovel portion 10. The two circular arcs involved are a circular arc having a 9-meter radius, on the one hand, and a circular arc having a 1-meter radius, on the other hand.
The profile of the second shovel portion 11 extends from the intermediate point J1 to the intermediate point J2.
Because its convexity is very small, the first shovel portion 10 is hardly visible, except when the ski rests on a planar surface and it is viewed from the side. Because the second shovel portion can have a greater convexity, it can be more visible and improve the skier's visual perception of the shovel.
The first and second portions of the shovel can be chosen to have the same convexity, such as a shovel whose profile has only one radius with a curvature R1.
In all cases, and in order to further improve the skier's visual perception of the shovel, the third shovel portion 12 can have an even greater curvature. The third shovel portion 12 is the end portion of the shovel. It is contiguous and tangent to the second shovel portion 11, and its length E is comprised between 80 mm and 130 mm. In the example shown, the length E of the third shovel portion is 120 mm and is measured from the end S of the ski.
The profile of the third shovel portion can have the shape of a circular arc having a radius R3, whereby R3≦R2≦R1.
Any shovel profile whose first and second shovel portions, namely, the portions located between the points LS and J2, fit into the space demarcated by these two curves 15, 16 and which does not have “flat portions”, corresponds to a shovel profile of the invention. The lack of a “flat portion” is established by the test of the “ski rolling movement in the area of the shovel”. The ski is supported on a planar surface, lifted by the tail, namely the rear portion, then one observes that the contact between the bottom surface of the ski and the contact surface moves from the contact line LS to the tip S, and that during this displacement, contact is made between the ski and the contact surface only along one line. At no time does such contact become a plurality of lines, or a surface.
The lack of a “flat portion” is also observed on the curve reproducing the lateral profile of the shovel. The shovel is considered to have a “flat portion” if, when taking two points P1 and P2 of the curve, positioned between the points LS and S, separated from one another by a 150-mm chord distance, the curve between P1 and P2 never moves away from the chord joining P1 and P2 by a value greater than 0.5 mm.
Conversely, the shovel is considered to have no “flat portion” when, irrespective of the points P1 and P2 placed at a 150-mm chord distance from one another on the curve reproducing the shovel lateral profile, there is at least one point of the curve between P1 and P2 that is more than 0.5 mm distant from the chord joining P1 to P2. When one refers to the distance from the curve to the chord, one refers to the shortest distance, namely, the distance measured on the bisecting line from the chord to the point being considered.
Conventionally, the tip height of a ski is measured by determining, at a point located 300 mm away from the front tip, the height H of the ski with respect to a planar surface on which it lies. The ski according to the invention has a high shovel since the height H is comprised between 5 mm and 25 mm.
The present invention is not limited to the embodiment hereinabove described, given only by way of example, but covers any equivalent embodiment.
| Number | Date | Country | Kind |
|---|---|---|---|
| 06.10280 | Nov 2006 | FR | national |
