Abstract:
A system for binding a shoe to a sports gear, such as a cross-country ski, using a fixing device fixed on the sports gear and including a stop cooperating with the shoe front end and an elastic catch cooperating with the sole associated catch arranged behind the sole front end and exerting on the sole a tension pressure towards the stop. The elastic catch is anchored on the fixing device, at the rear of the stop. The elastic catch and anchoring mechanism are longitudinally mobile countering the elastic mechanism.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation prosecution application (CPA) of U.S. application Ser. No. 09/423,319, filed Nov. 12, 1999, which is a U.S. National Stage under 35 U.S.C. 371 of PCT/FR99/00502, filed Mar. 5, 1999, not published under PCT Article 21(2) in English. The present application also claims priority under 35 U.S.C. § 119 of French Patent Application No. 98.03646 filed on Mar. 19, 1998. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The instant invention concerns a system for fixing a shoe to a sports gear, especially a gliding sport, such as cross-country skiing, touring, telemark skiing, ice skating or roller skating. 
     2. Description of Background and Relevant Information 
     In traditional fixing systems, i.e., bindings, of the type used in cross-country skis, the fastening of the shoe on the sports gear is generally obtained at the front thereof by means of a hinge type of coupling which allows the shoe to have a clearance with respect to the sports gear, i.e., the heel can be lifted. 
     Ice skates or roller skates are also known to possess a journalled coupling of the shoe with the sports gear, thereby allowing the stride to be lengthened and the speed to be increased. 
     Such coupling systems have proven themselves. However, their drawback is that the shoe sole has to be both rigid in the transverse direction and during torsion, while also remaining flexible enough to allow, insofar as possible, the foot to move naturally. 
     Since these requirements are contradictory and difficult to reconcile on one single element, the ski is not always controlled and guided in an optimum manner. 
     On the other hand, shoes belonging to such systems generally comprise a transverse axis located at the sole front end which can become a hindrance while walking. 
     Identical problems are encountered in other fields, especially skating. 
     Document WO 96/23558 proposes coupling the shoe front part, up to the zone known as the metatarsophalangian joint, by means of an elastic element anchored at one end to the fixing element, and that is fastened, by its free end in the shoe sole, at the rear of the zone. This elastic element provides the shoe with the desired stiffness characteristics transversely and in torsion, and at the same time exerts a constant return force of the shoe towards the sports gear. The result is an improved control and guidance of the sports gear. 
     Nonetheless, this elastic element is subjected to substantial fatigue and rapid wear due to the repeated bending of the foot during the sporting activity, such that the stiffness and elastic return properties indicated hereinabove become altered over time. 
     SUMMARY OF THE INVENTION 
     The object of the instant invention is to overcome these drawbacks and propose an improved fixing device that reconciles the problems of the lifting of the shoe heel, torsional control and material fatigue. 
     This object is achieved in the fixing device of the system according to the invention which is of the type comprising a front stop cooperating with the shoe front end, and an elastic catch cooperating with the sole associated catch arranged behind the sole front end, and exerting on the sole a tension pressure towards the stop, due to the fact that the elastic catch is anchored on the fixing device at the rear of the front stop. 
     This construction leads to a substantial reduction in the bending stresses of the elastic catch which, as a result, is less prone to wear by reason of fatigue, and furthermore exerts a more constant tension pressure and elastic return pressure. 
     According to a preferred embodiment, the anchoring mechanism of the elastic catch is longitudinally mobile countering the elastic mechanism. This construction guarantees that when the shoe bends, the return elasticity will preferably be provided by the compression of the elastic mechanism rather than by the bending of the catch. Consequently, the return elasticity can be better controlled. 
     Also, the anchoring of the elastic catch is advantageously constituted by a journal, which allows it to remain completely free of any bending related energy. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be better understood and other characteristics thereof shall become more apparent from the description that follows with reference to the annexed schematic drawings representing, by way of non-restrictive examples, several preferred embodiments of the invention in which: 
     FIG. 1 is a perspective view of a fixing device according to the invention during its operation; 
     FIG. 2 is a partial longitudinal cross-sectional view of the fixing device of FIG. 1 in the position for being put on; 
     FIG. 3 is a view similar to FIG. 2, in the closed position, when the shoe is at rest; 
     FIG. 4 is a view similar to FIG. 3 when the shoe is in the raised position; 
     FIG. 5 is a partial cross-sectional view of the shoe lower part; 
     FIG. 6 is a schematic view of another embodiment during the closure of the fixing device. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 shows the application of the coupling system, i.e., binding, according to the invention at the coupling of a ski  1  with a cross-country ski shoe  10 , such coupling occurring by way of a fixing device  20  and a guiding rib  70 . 
     As shown in FIG. 5, the shoe  10  comprises a sole  11 , equipped at its front end with a wide peripheral edge  12  that defines, at its joining with the shoe upper, a neck  13 , and comprises along the entire length of its lower surface a median longitudinal groove  14 . At its front end, the sole  11  curves upwardly in a slight curvature  11   a , in the manner of traditional mountaineering shoes. The curve  11   a  is adapted to facilitate the movement of the shoe, as explained below. 
     Furthermore, an insert  15  is fixed, for example, by screws  16  or even by co-extrusion, to the base of the groove  14 , in a zone corresponding substantially to the metatarsophalangian joint zone. This insert  15  defines a hook  17  oriented towards the rear. 
     All these shoe elements are adapted to cooperate with the fixing device  20  as explained below. 
     As shown in FIG. 2, the fixing device  20  is constituted of a seating  21  fixed on the ski  1  by screws  22 , and on which is journalled a latching lever  30 , about an axis  31 . Moreover, the latching lever  30  is connected to the seating  21  by two lateral connecting rods  32 , journalled, on the one hand, at  33  on the lever  30  and at a transverse axis  34  sliding in the lateral slots  23  of the seating, on the other hand. 
     The lever  30 -connecting rods  32  assembly forms a knuckle joint system whose neutral line is defined by the axes  31  and  34 . 
     Thus, when the lever  30  is lowered into the closed position shown in FIGS. 3 and 4, the journal axes  33  of the connecting rods  32  at the lever pass below the neutral line and the position of equilibrium is stable. The knuckle joint system requires a certain force to cross the axis  33  on both sides of the neutral position, and this guarantees that the lever will not open in an ill-timed manner. 
     A substantially cap shaped slide  35 , comprising two longitudinal walls  36  and a base wall  37  is also mounted on the transverse axis  34 . This slide  35  receives a compression spring  38 . 
     The spring  38  is kept between the base  37  of the slide, which comprises a projection  37   a  adapted for this purpose, and the front end  41  of a carriage  40 . The carriage  40  is slidably mounted in the seating  20  which comprises, to this end, a guiding slide  25  opening laterally along the sides of the seating  20 . An elastic catching wire  50  adapted to cooperate with the shoe hook  17  is journalled at the rear end  42  of the carriage  40 . 
     The elastic catching wire  50  is substantially U-shaped and comprises a transverse arm  52  adapted to cooperate with the hook  17  and two lateral arms  51  whose curved ends  53  are journalled on the carriage  40 . 
     The fixing device also comprises a front stop, or stop mechanism, incidentally constituted of a stirrup  60  comprising a horizontal arm  61  shaped in a circular arch and corresponding to the shape of the neck  13  of the shoe sole, and adapted to receive the latter and two lateral arms  62 , that are substantially vertical and journalled by their ends  63 , on the seating  20 . The stirrup  60  is arranged at the front of the elastic catching wire  50  and can therefore pivot about its ends  63 . 
     Other shapes could be envisioned for the stirrup depending on the shape of the sole. 
     The stirrup could also be provided not to cooperate with the sole neck  13 , but only with the upper surface of the peripheral edge  12 . 
     Finally, the fixing device comprises a guiding rib  70  whose transverse section corresponds to that of the shoe groove  14  and whose front end  71  is adjusted to the rear part of the seating  20  which also forms a guiding rib. 
     The fixing system according to the invention works as follows. The shoe  10  is positioned in the fixing device by introducing its sole front end in the stirrup  60  until the neck  13  comes into abutment with the horizontal arm  61  of the stirrup (see FIG.  2 ). 
     The shoe therefore becomes latched by lowering the lever  30 , which has the effect of pulling the carriage  40  and therefore the catching wire  50  towards the front until its arm  52  becomes housed in the base of the hook  17  (see FIG.  3 ). 
     This closing movement is assisted by the spring  38  which tends to push the carriage  40  back towards the front. The spring  38  also allows compensating for the snow wedges that could be formed in the shoe sole. 
     While skiing, the shoe, whose heel remains free, can bend, carrying the catching wire  50  along its path, which both slides towards the rear into the seating  20  by compressing the spring  38  by means of the carriage  40 , as well as pivots towards the top about its ends  53  (see FIG.  4 ). 
     The spring  38  therefore provides the return energy of the shoe towards the upper surface of the ski since it tends to relax, and therefore returns the catching wire  50  towards the front. 
     The return energy is therefore not provided by an elastic deformation of the wire  50  which therefore ages much better. 
     Furthermore, this return energy is completely defined since it is provided by the compression of a compression spring  38  and is better controlled and better controllable than would have been the case if it had been provided by the bending of a wire, as in the prior art. 
     In addition, the displacement, towards the rear with respect to the front stop mechanism  60 , of the anchor  53  of the spring wire provides a triangulation, enabling a better retention of the shoe, especially in the transverse direction. 
     This triangulation, and especially the journalled anchoring of the catching wire  50  by its ends  53 , also allows for a greater bending clearance of the shoe, a property desired in cross-country skis. 
     It should be noted that the journalled anchoring of the stirrup  60  on the seating  20 , combined with the rounded shape  11   a  of the sole front, enabling a slight pivoting thereof towards the front when the shoe pivots, therefore allows it to accompany the motion of the movement of the shoe at the end of a stride, and therefore increases the amplitude of the stride even further. In practice, an increase on the order of 10 to 15° of the clearance of the shoe at the end of a stride can be obtained due to the rounded shape  11   a  of the sole thereof towards the front, which is especially interesting. 
     Finally, the presence along the entire length of the shoe sole, of the guiding rib  70 , which is extended by the rear portion of the seating  21  up to the shoe front end, allows controlling the movement of the shoe until the motion ends, by providing it with a support and an abutment in the transverse direction. 
     As can be seen especially from FIG. 1, the guiding rib  70  is interrupted in the metatarsal zone for the passage of the catching wire  50  and the shoe associated hook. 
     The shapes of the guiding edges are designed also to optimize the guidance of the shoe. 
     FIG. 6 is a schematic illustration of a second embodiment in which similar or identical elements have been designated by the same references increased by  100 . 
     In fact, this fixing system comprises the same latching elements or, in other words, a front stop stirrup  160 , journalled at  163 , a catching wire  150  connected to a slidably mounted carriage  140 , which is biased towards the front by a spring  138  and whose longitudinal displacement is controlled by a lever  130 . 
     The main difference lies in the position of the journals  131  and  134  of the lever  130  and the connecting rods  132  that are located at the rear of the spring  138 . Otherwise, the operation is identical. 
     The instant invention is not limited to the embodiments described hereinbefore by way of non-restrictive examples, and can encompass all similar or equivalent embodiments.