Abstract:
An article of footwear, such as a ski boot that includes a rigid upper comprised of a shell base equipped with a rigid tongue and overlaid by a hinged collar, the shell base including a wide opening extending from the top of the upper to the forefoot, the opening separating a lateral edge and a medial edge, which extend parallel to one another without overlap. The rigid tongue is wider than the width of the opening and comprises a lateral wing and a medial wing intended to be positioned under the lateral edge and the medial edge, respectively.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is based upon French Patent Application No. FR 15/00474, filed Mar. 12, 2015, the disclosure of which is hereby incorporated by reference thereto in its entirety, and the priority of which is claimed under 35 U.S.C. §119. 
       BACKGROUND 
       [0002]    1. Field of the Invention 
         [0003]    The invention relates to an article of footwear, such as a ski boot and, more particularly, a ski boot for alpine skiing. More specifically, the invention relates to ski boots comprising a rigid shell made of a plastic material, within which an inner liner made of a flexible material is inserted. 
         [0004]    2. Background Information 
         [0005]    Ever since ski boots of the aforementioned type were introduced, various constructions have been proposed by manufacturers. In particular, there have been so-called rear-entry ski boots comprising a hinged rear spoiler which was tilted backwards to enable one&#39;s foot to be inserted. In a rear-entry ski boot, the front portion, from the forefoot to the top of the boot, forms a block of which the outer volume is generally not adjustable. The boot is then adapted to the foot of the skier using an internal tightening device which acts on the inner liner. This type of construction has since been abandoned by manufacturers, except for children&#39;s shoes, because boots constructed in this way have proven to perform poorly, in addition to being bulky. 
         [0006]    Another ski boot shell construction is that of the alpine ski boot fitted with a cuff. In boots of this type, the shell is comprised of a shell base, a cuff, and a hinged collar. The shell base comprises a wide longitudinal opening extending from the top of the boot to the forefoot. This opening comprises two lateral edges that do not overlap. The cuff is hinged on the shell in the area of the forefoot, and it is intended to cover the longitudinal opening of the shell. As the cuff is positioned above the shell, its forward tilting completely frees the longitudinal opening. It is in this position of the cuff that the skier can very easily insert the foot. Indeed, the skier can easily slip his/her foot into the opening, which extends far forward. With such a boot, the skier does not need to exert substantial force to space apart the lateral edges of the opening. This construction is still used, in particular for touring ski boots, because it enables putting on and the loosening of the boot with great easey. However, this boot also performs poorly. Furthermore, the cuff is a bulky element whose rough aesthetics no longer meets user&#39;s expectations. 
         [0007]    Finally, the most widely used construction of alpine skis is the overlap-style, or alpine ski boot with overlapping flaps. In this construction, the lateral edges of the longitudinal opening overlap one another. These boots are particularly popular for ski racing and for any high-performance practice of alpine skiing. Indeed, friction is generated between the two flaps when they are pressed against another. It is through this friction that these boots provide a good transmission of forces, especially during forward bending of the skier&#39;s leg. However, the major drawback of these boots is the difficulty in putting on and tightening the boot. Furthermore, the inner liner positioned in such a shell must practically be fitted with a rigid plate for the distribution of forces generated by the tightening of the tightening buckles. In practice, the distribution plate is formed by a plate made of molded or injected plastic, which is sewn onto the tongue of the liner. In the end, there are at least three layers of plastic thatch are superimposed on the skier&#39;s instep. Thus, overlap ski boots are rather heavy, uncomfortable, and bulky. 
       SUMMARY 
       [0008]    The invention improves upon the construction of articles of footwear and, more particularly, the construction of alpine ski boots. The invention provides an article of footwear, or boot, that does not possess the disadvantages of prior art constructions. In particular, the invention provides a high-performance, comfortable, lightweight, and compact boot, i.e., a boot that fits snuggly around the foot, is easy to put on, and has an efficient transmission of forces from the leg to the forefoot and to the ski. 
         [0009]    To these ends, an article of footwear of the invention and, more particularly, a ski boot of the invention, comprises a rigid upper comprised of a shell base equipped with a rigid tongue and overlaid by a hinged collar in which the shell base comprises a wide opening extending from the top of the upper to the forefoot, such opening separating a lateral edge and a medial edge, both of which extend parallel to one another without overlapping, and in which the rigid tongue is wider than the opening and comprises a lateral wing and a medial wing positioned under the lateral edge and the medial edge, respectively. 
         [0010]    An article of footwear according to the invention can also be described as one that, further comprises one or any technically feasible combination of several of the characteristics listed below, whereby:
       the tongue is fixed to the top of the front portion of the upper;   the tongue comprises a central plate that is raised with respect to the lateral and medial wings;   the tongue comprises a stiffening rib;   a flexible panel connects the lateral side and medial side to one another;   the boot further comprises a removable inner liner, a central portion of which is devoid of a rigid plate for distributing the forces;   the tongue is made of a molded or injected plastic material, or a composite material;   the flexible panel comprises a gusset in its lower portion and an apron in its upper portion, the flexible panel being fixed to the tongue in the area of the top of the apron.       
 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]    Other characteristics and advantages of the invention will be better understood from the description that follows, with reference to the annexed drawings illustrating, by way of non-limiting embodiments, how the invention can be carried out, and in which: 
           [0019]      FIG. 1  is an overall view of a boot according to an embodiment of the invention; 
           [0020]      FIG. 2  is an exploded view of the three main components of the boot of  FIG. 1 ; 
           [0021]      FIGS. 3 and 4  are transverse cross-sectional views of the boot; 
           [0022]      FIG. 4A  is a cross-sectional view of an alternative embodiment; 
           [0023]      FIG. 5  is a perspective view of the inner liner of the boot; and 
           [0024]      FIG. 6  is a partial internal view of the tongue and of the gusset. 
       
    
    
     DETAILED DESCRIPTION 
       [0025]    The boot  1 , within the scope of the invention, is an alpine ski boot comprising a rigid shell made of plastic material. Plastic materials that are suitable for manufacturing such a shell include polyamide, polypropylene, polyurethane, polyester, etc. The rigidity of the shell is a necessary condition for the practice of alpine skiing, to the extent that the forces that the skier must exert to steer the skis not only are substantial but must imperatively transit through the boot and the ski bindings. In practice, such rigidity can be achieved by the selection of materials having a flexural modulus between 200 and 1800 MPa or by the selection of materials having a flexural modulus in a narrower range, between 200 and 1000 MPa. 
         [0026]    An inner liner  2  is positioned within the shell for comfort. The liner  2  is made by assembling various elements such as flexible panels made of fabric or plastic materials, which, in a particular embodiment, can be in the form of foam. 
         [0027]    The shell itself can be comprised of an assembly of various elements. In the embodiment described here, the shell includes a shell base  3 , a hinged collar  4 , and a tongue  5 . These three elements form the main rigid frame of the shell, which is supplemented by other components that include those described in detail below, as well as others. 
         [0028]    The shell base  3  is made by injection molding of polyurethane having a flexural modulus between 200 and 1000 MPa. Conventionally, the shell base  3  comprises the sole  31  and the flanges  32  of the lower portion of the boot upper. The upper portion of the shell base  3  is formed with a wide opening  33 . The front portion  331  of this opening extends as far as to the forefoot. 
         [0029]    The front portion of the opening  331  is demarcated laterally by a lateral edge  322  and a medial edge  323 , on the one hand, and longitudinally by the rear end of the cap  321 , on the other hand. The cap  321  is the portion of the shell base which covers and surrounds the tip of the foot of the user. 
         [0030]    The lateral edge  322  and medial edge  323  do not overlap one another. Thus, the front portion of the opening is widely gaping, and it is not even necessary to exert force to space apart the flanges of the shell. The lateral and medial edges  322 ,  323  are substantially parallel to one another, and there is a gap of between 2.0 cm and 6.0 cm therebetween, this gap constituting the width of the opening. 
         [0031]    The collar  4  is fixed to the shell base  3  so as to pivot in relation thereto about an axis coinciding with the hinge axis of the malleoli. During walking phases, the collar can then follow the rotation of the leg of the user. The collar  4  is also capable of being attached to the rear of the shell base  3  in order to block the rotation of the collar, particularly during skiing phases. The collar  4  comprises two flaps  42 ,  43 . These flaps are large in size. Thus, when the boot is closed, they come to rest on one another and completely cover an upper portion of the tongue  5 . 
         [0032]    As can be seen in  FIG. 4 , the tongue  5  is comprised of an element obtained by injection of a thermoplastic material. This material may be of the same type as that used to make the shell base  3 . In accordance with a non-limiting embodiment, the tongue  5  is made in one piece, from the front of the boot to the top thereof, in order to ensure a good transmission of forces from the leg of the user to the forefoot. 
         [0033]    In the area of the forefoot, the tongue comprises an element for cooperation with mechanisms for attachment to the shell base  3 . In the embodiment described here, this is an opening  55  in which a rivet  8  is inserted. Any of other attachment mechanisms can be utilized within the scope of the invention. 
         [0034]    In a non-limiting embodiment, the front end  56  of the tongue, in which the opening  55  is arranged, is secured to top of the cap  321 . This characteristic substantially improves the distribution of forces that are transmitted from the tongue  5  to the shell base  3 , particularly during forward bending phases. Furthermore, fixing the tongue from the top makes it possible to save space inside the shell. The inner volume thus gained can be used to improve comfort or insulation, because an additional damping or insulation layer can be used for the same inner volume. This construction also makes it possible to reduce the outer volume of the front portion of the shell base  3 . In this case, a ski boot is produced with improved aesthetics as it appears refined in comparison to prior art ski boots. 
         [0035]    The tongue also comprises two slits  56 ′ at its top, which are used for fastening a pulling strap  57 . 
         [0036]    The tongue  5  comprises a central plate  51  extending over almost the entire length thereof, and which is bordered on each side by wings, including a lateral wing  52  and a medial wing  53 . As can be seen in  FIGS. 3 and 4 , along a transverse cross section, the plate  51  is raised with respect to the wings. Furthermore, elongated ribs  54 , extending from the lower surface of the plate, fill the space located behind the plate so as to provide a surface for support of the tongue  5  on the inner liner that has a uniform curvature. The longitudinally extending ribs  54  also extend over almost the entire length of the tongue. 
         [0037]    The wings  52 ,  53  of the tongue are provided to be positioned under the lateral and medial edges  322 ,  323  when the boot is closed and the closure buckles are tightened. Two parallel overlaps thus occur over the entire lower portion of the tongue  5 , that is to say the portion which is opposite the lateral  322  and medial  323  edges. The overlap of the medial edge  323  occurs on the medial wing  53 , and the overlap of the lateral edge  322  occurs on the lateral wing  52 . 
         [0038]    Each of the two parallel overlaps has a width L, measured in a transverse plane, between 8.0 mm and 30 mm or, in a narrower range, between 10 mm and 25 mm. Furthermore, they are spaced from one another by a distance D between 25 mm and 60 mm. 
         [0039]    Structurally, when the boot is closed and properly tightened, that is to say typically during a skiing phase, the overlaps constitute a pair of two parallel reinforcements that begin in the upper portion of the shell base  3  and extend to the forefoot region thereof. This pair of reinforcements has the effect of stiffening the boot across the entire shell base  3 . 
         [0040]    Above the shell base  3 , due to the overlapping of the flaps  42  and  43  of the collar  4 , the collar completely surrounds the lower leg of the user and thereby covers the tongue  5 . This construction has the effect of properly maintaining the tongue in place within the shell base  3  when the skier bends the leg forward and the pressure of the tibia on the tongue tends to tilt the tongue forward. 
         [0041]    In addition, the central plate  51  and the ribs  54  also contribute to stiffening the boot, in particular because they prevent deformations of the tongue  5  when the skier bends forward. 
         [0042]    A flexible panel  6  is fixed to the lateral edge  322  and the medial edge  323  of the opening  33 . In this non-limiting embodiment, the panel  6  is positioned on the outer surface of the shell base  3  and passes beneath the tongue  5 . A gusset  61  is thus produced to ensure that the boot is impervious. Snow and water cannot penetrate into the boot, even when the boot is not closed and the two lateral and medial edges are spaced from each other to facilitate insertion of the foot of the user. 
         [0043]      FIG. 6  shows a partial interior view of the tongue  5 . It can be seen that the gusset  61  present in the lower portion of the flexible panel  6  is extended upward by an apron  62 . The apron  62  has substantially the shape of a triangle. Mechanisms are provided at the top of the apron  62  for fixing the apron to the tongue  5 . In this case, in the embodiment described, it is a main rivet  63 . The main rivet  63  can possibly be associated with two lateral rivets  64  to fix the tongue  5  to the flexible panel  6 . 
         [0044]    The fixing of the apron  62  to the tongue  5  via the main fixing mechanisms occurs in the upper half-portion of the tongue, above the zone corresponding to the instep. The other fixing mechanisms, constituted in this case by the two lateral rivets, are in a lower position on the tongue, approximately in the zone of maximum curvature thereof. This is the zone in which, from the forefoot, the tongue switches from a mainly horizontal or slightly inclined orientation to a mainly vertical orientation. 
         [0045]    In a non-limiting embdoment, the flexible panel  6  is slightly expandable or not expandable. Thus, the flexible panel acts like a brake for the tongue  5  when the user pulls on the pulling strap  57  to move it away. This is what makes it possible to prevent the entire length of the wings of the tongue from passing above the lateral and medial edges  322 ,  323 . The length of the apron  62  is selected so that, when the tongue is opened to the maximum, there is still frontal contact, somewhere along the length of the wings, between the edge surface of the lateral and medial edges and the edge surface of the wings. Thus, it is easy to reposition the tongue under the lateral and medial edges, to close the boot. 
         [0046]      FIG. 4  shows a cross section of the shell base  3  and the tongue  5  when the buckles  37  are loose or open. The flanges  32  of the shell base  3  then reassume their free state position. To facilitate foot insertion into the boot, the user can increase the opening of the boot by pulling upward and forward on the strap  57 . Thereafter, the edges of the tongue take support on the lateral and medial edges  322 ,  323  and space them from one another. 
         [0047]      FIG. 4A  shows a cross section of an alternative embodiment of the invention. To facilitate understanding, the actual position of the cross section of  FIG. 4A  is referenced in  FIG. 4 . In this embodiment, additional mechanisms are provided to prevent the tongue  5  from coming out of its location. These mechanisms  9  for retaining the tongue  5  are comprised of a strip  91  fixed to the lateral edge  322  and to the tongue  5 . The two ends of the strip may be fixed using any suitable mechanism, such as a rivet, an adhesive, stitches, a screw/nut. 
         [0048]    In the embodiment shown here, an opening  521  is arranged on the tongue  5 , between the plate  51  and the lateral wing  52 . The strip  91  is fixed to the lateral edge  322 , and then extends through the opening  521 . It is then fixed under the tongue  5 . The length of the strip  91  is judiciously selected, so that the amplitude of relative movement between the lateral edge  322  and the tongue  5  is limited. Thus, the lateral wing  52  cannot pass above the lateral edge. The presence of retaining mechanisms  9  only on the lateral or medial side is sufficient to prevent the lower portion of the tongue from coming out of its normal position under the lateral  322  and medial  323  edges. 
         [0049]    Advantageously, the retaining mechanisms  9  may be positioned under one of the buckles  37  so as to be practically invisible. 
         [0050]      FIG. 5  shows a perspective view of the inner liner of the boot according to the invention. Like most liners provided for rigid ski boots, it is constituted by assembling various flexible panels that can be fabrics, non-woven webs, films of plastic material, and flexible foam panels. Furthermore, it includes a lengthy front portion  21  with no opening, whereas two vertical slits  22 ,  23  originate in the area of the instep and extends to the top of the liner. The two vertical slits  22 ,  23  demarcate a tongue portion  25  of the liner. 
         [0051]    As is the case for liners for modern high-performance alpine ski boots, the liner does not comprise any rigid distribution plate. Indeed, the outer surface of a front portion  24  of the liner is made from flexible materials. The front portion  24  corresponds to the portion of the liner located beneath the tongue  5 , when the liner is inserted into the shell base. 
         [0052]    Further, at least because the invention is disclosed herein in a manner that enables one to make and use it, by virtue of the disclosure of particular exemplary embodiments, such as for simplicity or efficiency, for example, the invention can be practiced in the absence of any additional element or additional structure that is not specifically disclosed herein.