Abstract:
A lateral guidance apparatus for a ski boot including a longitudinal guidance element projecting from the ski for engagement with a complementary shaped groove in the sole of the boot. On either lateral side of the groove of the boot is a support surface for engagement with a support surface on the interior side of the guidance element and a support surface on the exterior side of the guidance element. With the boot supported upon the ski, the configuration of the support surfaces of the boot and the ski orient the boot, and the skier&#39;s lower leg, toward the interior side of the ski.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a lateral guidance apparatus for a cross-country ski boot, including a longitudinal rib which projects from the upper surface of a ski, as well as a cross-country ski and boot adapted for this purpose. 
     2. Description of Background and Relevant Information 
     Cross-country skis which include a longitudinal rib on their upper surfaces are known. This rib can form an integral portion of the ski or it can be formed on a plate which is itself affixed to the upper surface of the ski. Such a rib generally has a generally trapezoidal cross-section. Otherwise stated, it is defined by an upper horizontal surface and two lateral inclined surfaces. The upper longitudinal rib contributes to the lateral guidance of the boot mounted on the cross-country ski, which is adapted for this purpose by virtue of the provision of a groove in its sole having a complementary shape in cross-section to that of the rib of the ski. During the flattening of the foot on the ski during the practice of cross-country skiing, the groove of the sole, in effect, progressively caps the lateral guidance rib which intervenes to laterally maintain the boot, and preferably well-centered, on the ski. 
     Cross-country skiers more and more often use a &#34;skating&#34; or &#34;half-step skating&#34; technique in which the skier, to ensure his or her propulsion on at least one of the skis, inclines the ski with respect to its direction of movement. Yet, with such a technique the skier often has a tendency to take &#34;too much edge,&#34; i.e., there is an increased tendency for the skier to twist his or her ankle. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to overcome the aforementioned disadvantage in the prior art by providing a lateral guidance apparatus for a boot on a cross-country ski including, at its upper portion, a longitudinal rib having an internal side and an external side, the rib constituting a lateral guidance element for a boot having, in its sole, a longitudinal groove which caps the rib in the course of flattening the boot on the ski and a lower support zone on either side of the groove. The lateral guidance apparatus further includes two elastic elements positioned on opposite sides of the longitudinal rib, each elastic element having an upper surface, wherein the upper surfaces of the elastic external element and the elastic internal element and the lower support zones of the sole positioned on either side of the groove in the sole are positioned, with respect to one another, in a manner such that in the position of the sole substantially flattened on the ski, and the two elastic elements are compressed, the sole is inclined transversely from top to bottom and from the exterior of the ski towards the interior thereof. 
     According to a further aspect of the invention, the upper surface of the elastic element which is positioned on the exterior side of the ski is positioned at a level higher than the level of the upper surface of the elastic element which is positioned on the interior side of the ski. 
     According to a further aspect of the invention, an external shaped section and an internal shaped section are affixed to the ski and have respective upper surfaces. The external elastic element and the internal elastic element have substantially the same thickness and are, respectively, affixed on the horizontal upper support surfaces of the external shaped section and the internal shaped section. The horizontal support surface of the external shaped section is positioned at a level above that of the horizontal support surface of the internal shaped section. 
     According to a still further embodiment of the invention, the external elastic element has a thickness greater than that of the internal elastic element and the external shaped section and the internal shaped section are affixed, respectively, on the horizontal support surfaces of the shaped sections, which are positioned substantially at the same level. 
     According to a still further embodiment of the invention, the external elastic element and the internal elastic element are constituted by shaped sections totally made of elastic material, which include respective upper surfaces and which are substantially coplanar and inclined with respect to the horizontal, the inclination being such that the upper surface of the external shaped section is at a level above that of the upper surface of the internal shaped section. 
     According to a still further embodiment of the invention, a molded shaped section made of a rigid material substantially mates with the shape of the cross-country ski, the molded shaped section having upper support surfaces, respectively, on an external side and on an internal side of a portion of the molded shaped section which overlies the longitudinal rib. The upper support surfaces of the molded shaped section are substantially coplanar and inclined with respect to the horizontal such that the external upper support surface is positioned at a level above that of the internal upper support surface, and the external elastic element and the internal elastic element have substantially the same thickness and are situated, respectively, on the external upper support surface and the internal upper support surface. 
     According to a still further aspect of the invention, a plate is affixed to the ski and has an external wing and an internal wing with respective substantially horizontal upper surfaces. The longitudinal rib is formed integrally with the plate between the wings, the external elastic element and the internal elastic element have substantially the same thickness and are affixed respectively, on the upper horizontal surfaces of the external wing and the internal wing of the plate, the internal wing having a thickness less than that of the external wing. 
     According to a still further aspect of the invention, the external elastic element has a thickness greater than that of the internal elastic element, and the two elastic elements are respectively affixed on the upper horizontal surfaces of the external wing and the internal wing of the plate. 
     According to a still further aspect of the invention, the external elastic element and the internal elastic element have substantially the same thickness and are affixed on the upper respective surfaces of the wings and the upper surfaces of the wings are substantially coplanar and inclined with respect to the horizontal such that the internal upper surface is lower than the external upper surface. 
     According to a still further aspect of the invention, the external elastic element and the internal elastic element are affixed on the upper horizontal surfaces of the external wing and the internal wing, the external wing and the internal wing have substantially the same thickness and the upper surfaces of the elastic elements are substantially coplanar and are inclined with respect to the horizontal, such that the upper surface of the internal elastic element is lower than the upper surface of the external elastic element. 
     According to a still further aspect of the invention, the external elastic element and the internal elastic element have substantially the same thickness and are positioned at substantially the same level and the lower support zone of the sole situated on the interior side of the ski has a first predetermined height, with respect to the bottom of the groove, which is less than a second predetermined height of the lower support zone situated on the external side of the ski. 
     The present invention can be further defined as a lateral guidance apparatus for a ski boot including a longitudinal guidance element for being affixed to a ski and for engagement with a substantially complementary shaped groove in the sole of the boot; an internal longitudinally extending support surface located on an internal side of the longitudinal guidance element; an external longitudinally extending support surface located on an external side of the longitudinal guidance element; the internal longitudinally extending support surface and the external longitudinally extending support surface being configured and arranged relative to the boot and the ski during the course of skiing such that a longitudinal median plane of the boot is inclined relative to a longitudinal median plane of the ski. 
     According to a further aspect of the invention, an internal elastic element and an external elastic element are provided, wherein the internal elastic element includes the internal longitudinally extending support surface, and wherein the external elastic element includes the external longitudinally extending support surface. 
     According to a further aspect of the invention, the internal elastic element and the external elastic element have substantially the same thickness or different thicknesses. 
     According to a still further aspect of the invention, an internal shaped section is provided for engagement with an internal ski surface and an external shaped section is provided for engagement with an external ski surface, wherein the internal shaped section and the external shaped section each include an upper surface for supporting the internal elastic element and the external elastic element, respectively. 
     According to a still further aspect of the invention, a further section is provided connecting the internal shaped section and the external shaped section, wherein the further section is configured and arranged for overlying the longitudinal guidance element. 
     According to a still further aspect of the invention, a plate is provided in a longitudinally extending generally central portion from which the longitudinal guidance element projects. The plate includes a substantially continuous lower surface for engagement with a substantially continuous upper surface of the ski. 
     According to a still further aspect of the invention, the internal elastic element and an external elastic element are provided wherein the internal elastic element includes the internal longitudinally extending support surface, and wherein the external elastic element includes the eternal longitudinally extending support surface. 
     The present invention can be further defined as a sole of a ski boot including a longitudinally extending groove for engagement with a longitudinal guidance element of a ski for maintaining lateral guidance of the boot upon the ski; an interior lower support surface on an interior side of the groove for engagement with an interior ski support surface; an exterior lower support surface on an exterior side of the groove for engagement with an exterior ski support surface wherein, when the interior lower support surface and the exterior lower support surface engage a horizontal support surface, the ski boot sole tends to incline the lower leg of a skier towards an interior side of the ski when the ski boot is worn by the skier. 
     According to a further aspect of the invention, an interior projection includes the interior lower support surface and an exterior projection includes the exterior lower support surface, wherein the exterior support projection has a height greater than a height of the interior support projection. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will now be described with reference to the annexed drawings, given by way of non-limiting example only of various embodiments of the invention in which: 
     FIG. 1 is a vertical transverse cross-sectional view of a cross-country ski provided with a lateral guidance apparatus according to the invention, a cross-country ski boot cooperating with the ski being shown spaced from the lateral guidance rib; 
     FIGS. 2 and 3 are vertical transverse cross-sectional views similar to those of FIG. 1, illustrating the ski and boot the moment in which the sole of the boot comes into contact only with the external elastic element, and at the moment in which the sole flattens the two elastic elements, after the flattening of the boot on the ski, respectively; 
     FIGS. 4-10 are views in vertical transverse cross-section of respective embodiments of the lateral guidance apparatus according to the invention; 
     FIGS. 11 and 12 are vertical transverse cross-sectional views of a further embodiment illustrating, respectively, the ski boot being spaced from the rib and the ski boot positioned flat upon the ski; and 
     FIG. 13 is an elevational view of a cross-country ski provided with a lateral guidance apparatus of a boot according to the invention. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     The present invention attempts to overcome the disadvantages noted above by ensuring an automatic elastic return of the boot at the beginning of the flattening movement of the foot of the skier, in an inclined position transversely towards the interior of the ski. 
     To this end, the lateral guidance apparatus of a boot on a cross-country ski includes, at its upper portion, a longitudinal rib, this rib constituting a lateral guidance element for a boot having, in its sole, a longitudinal groove which caps the rib during the flattening movement of the foot on the ski, and an elastic element positioned on either side of the longitudinal rib, wherein the upper surfaces of the external and internal elastic elements and the lower support zones of the portions of the sole situated on each side of the groove in the sole are positioned, with respect to one another, in a manner such that during the flattening the boot on the ski, when the two elastic elements are compressed, the boot is inclined transversely from top to bottom and from the exterior of the ski towards the interior thereof. 
     According to a first embodiment of the invention, the elastic element positioned on the exterior side of the ski has an upper surface positioned at a level above the level of the upper surface of the elastic element positioned on a lower interior side of the ski. 
     Referring to FIGS. 1-3, it can be seen that these figures represent a cross-country ski 1 whose cross-section is shaped in a manner so as to form a longitudinal upper guidance rib 2, having a cross-section substantially in the form of an isosceles trapezoid, defined by an upper horizontal surface 2a and two lateral inclined surfaces 2band 2c. The upper guidance rib 2 is connected, by inclined lateral surfaces 2d and 2e, of a lesser slope than the lateral inclined upper surfaces 2b and 2c, to the respective sides 1a, 1b of ski 1. On the inclined lateral lower surfaces 2d and 2e there extend two longitudinal shaped applied sections 3 and 4, made of a relatively rigid material, each of which have a cross-section in the form of a right-angle triangle. 
     These shaped sections 3 and 4, respectively, include a vertical lateral surface 3a and 4a, which are preferably substantially coplanar with the respective side 1a and 1b of the ski; an upper substantially horizontal surface 3b and 4bextending to the guidance rib 2; and a lower inclined surface 3c and 4c constituting the hypotenuse, in cross-section, of the right-angle triangle. The inclined surfaces 3c and 4c of the shaped sections 3 and 4 are, respectively, in contact with the lateral inclined lower surfaces 2d and 2e and they have substantially the same slope. 
     According to the invention, the upper horizontal surfaces 3b and 4b of the shaped sections 3 and 4, respectively, carry elements 5 and 6 made of an elastic material. In FIGS. 1-3 elastic elements 5 and 6 have substantially the same thickness. However, the upper horizontal surface 4b of the right shaped section 4, which is assumed to be positioned on the exterior side of ski 1, is at a level greater than that of the upper horizontal surface 3b of the left shaped section 3, which is positioned on the interior side and, consequently, the level of the upper surface of the right or external elastic element 6 is at a higher level than that of the upper surface of the left or internal elastic element 5. 
     With the cross-country ski there cooperates a boot which is shown schematically only by its sole 7. This sole includes, in its central portion, a longitudinal groove 8, opened downwardly and having a trapezoidal cross-section corresponding substantially to that of the longitudinal guidance rib 2 of ski 1. This groove 8 is adapted to cap the guidance rib 2, in the course of flattening of the boot on ski 1, during cross-country skiing. The groove 8 defines, in the lower surface of sole 7, two horizontal support zones 7a and 7b positioned, respectively, on opposite sides of the central groove 8. These support zones 7a and 7b are adapted to press against the elastic elements 5 and 6 when the boot is flattened on the ski. 
     As can be seen in FIG. 2, during the flattening of the boot on the ski, the sole 7 first comes into contact with its right support zone 7b, with the upper surface of the external elastic element 6 which is positioned, in its entirety, at a level higher than that of the internal elastic element 5. The left support zone 7a of sole 7 then comes into contact with the upper surface of the internal elastic element 5. 
     At the end of the flattening of the boot on the ski, i.e., just before the beginning of the return movement ensuring the propulsion of the skier, the sole 7 occupies the position illustrated schematically in FIG. 3. By virtue of the offsetting in relative height of the two elastic elements 5 and 6, the boot is then slightly inclined transversely, from top to bottom and from the exterior towards the interior, as is indicated schematically by the line xy. Stated in another manner, the longitudinal median plane of the boot is inclined toward the interior of the ski with respect to the longitudinal median plane of the ski. At the beginning of the flattening movement of the boot, the elastic elements 5 and 6 are compressed and push the sole 7 upwardly. 
     In the alternative embodiment of the invention shown in FIG. 4, the shaped sections 3 and 4 have substantially the same height and the elastic elements 5 and 6 are thus situated at substantially the same level. However, the external elastic element 6 has a thickness greater than that of the internal elastic element 5. Here again, at the end of the flattening of the boot, the boot is inclined transversely, as is shown schematically by the line xy. 
     In the alternative embodiment of the invention shown in FIG. 5 the lateral guidance apparatus includes two shaped sections 9 and 10 which are totally made of an elastic material, and which are pressed and affixed directly on ski 1. These two shaped sections 9 and 10 each have a cross-section of triangular shape and they include lateral and vertical surfaces 9a and 10a which are substantially coplanar with the sides 1a and 1b of ski 1, upper surfaces 9b and 10b inclined with respect to the horizontal and positioned in substantially the same plane xy, and lower inclined surfaces 9c and 10c, respectively pressed against the lower inclined surfaces 2d and 2e of ski 1. The inclination of the upper surfaces 9b and 10b in the plane xy is such that the upper surface 10b of the external shaped section 10 is at a level higher than that of the upper surface 9b of the internal shaped section 9. 
     In the alternative embodiment of the invention shown in FIG. 6, the cross-country ski carries, at its upper portion, a molded shaped section 11 made of a rigid material which mates with the shape of cross-country ski 1. This shaped section 11 has two upper surfaces 11a and 11b positioned on opposite sides of the central rib 2 which is capped with a trapezoidal portion 11c of shaped section 11. The upper surfaces 11a and 11b are substantially coplanar and inclined with respect to the horizontal, in a manner such that the upper external surface 11b is positioned at a level greater than that of the internal upper surface 11a. Elastic elements 5 and 6, having substantially the same thickness, are affixed to respective upper surfaces 11a and 11b. Elements 5 and 6 are adapted to be compressed by the support zones 7a and 7b of sole 7, while giving to the boot a position which is inclined transversely along the line xy, upon the flattening of the boot on the ski. 
     In the alternative embodiments of the invention shown in FIGS. 7-10, the cross-country ski 1 has a cross-section which is substantially rectangular and which carries, on its upper horizontal surface 1c, a small plate 12, made of a relatively rigid material, in the central portion of which is formed a longitudinal guidance rib 15, which forms an integral portion of the plate 12 and defines, on plate 12, two horizontal wings, namely, an internal wing 12a and an external wing 12b. 
     In the alternative embodiment shown in FIG. 7 the internal wing 12a of plate 12 has a thickness less than that of the external wing 12b. The two wings 12a and 12b carry, respectively, on their upper horizontal surfaces, elastic elements 5 and 6 having substantially the same thickness. As a result, the upper surface 12c of the external elastic element 6 is positioned at a level above the level of the upper surface 12d of the internal elastic element 5, as in the case of FIG. 1. 
     In the alternative embodiment of the invention shown in FIG. 8, the two wings 12a and 12b of plate 12 have substantially the same thickness and they carry, on their upper horizontal surfaces 12c and 12d, respective elastic elements 5 and 6 having different thicknesses. More particularly, the external elastic element 6 has a thickness greater than that of the internal elastic element 5, as in the case illustrated in FIG. 4. 
     In the alternative embodiment of the invention shown in FIG. 9, the two wings 12a and 12b have upper respective surfaces 12c and 12d which are inclined with respect to the horizontal, in the xy plane, the upper internal surface 12c being lower than the external upper surface 12d. These inclined surfaces 12c and 12d carry, respectively, elastic elements 5 and 6 having substantially the same thickness, as in the case illustrated in FIG. 6. 
     In the alternative embodiment of the invention shown in FIG. 10, the two wings 12a and 12b of plate 12 have substantially the same thickness and they carry, on their upper horizontal surfaces 12c and 12d, elastic elements 13 and 14 whose upper surfaces 13a and 14a are inclined with respect to the horizontal, in the plane xy, the upper surface 13a of the internal elastic element 13 being lower than the upper surface 14a of the external elastic element 14. 
     In the alternative embodiment of the invention shown in FIGS. 11 and 12, the two elastic elements 5 and 6, which are positioned on opposite sides of the longitudinal guidance rib 2, have substantially the same thickness and are positioned at substantially the same level. In this case, the two portions of the sole 7 which are defined on either side of the central groove 8 do not have the same height. More particularly, as can be seen in FIG. 11, the left or internal portion which includes the lower support zone 7a, has a height a, with respect to the bottom 8a of groove 8, which is less than the height b of the right or external portion of the sole which includes the lower support zone 7b. Consequently, here again, during the flattening of the boot on the ski, the boot is inclined transversely towards the interior, along the plane xy, as shown in FIG. 12. 
     Although the invention has been described with respect to particular materials, embodiments and means, it is to be understood that the invention is not limited to the particulars disclosed and extends to all equivalents within the scope of the claims.