Abstract:
An article of footwear of the type that includes upper, an outer sole, and the following elements, listed from the inside toward the outside of the article of footwear: a comfort liner; a frame for holding the foot and for transmitting forces, made of a substantially inextensible material to transmit the forces for tightening the foot and to hold the foot; and an outer envelope for protecting against exterior elements.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based upon French Patent Application No. 03.07032, filed Jun. 12, 2003, the disclosure of which is hereby incorporated by reference thereto in its entirety and the priority of which is hereby claimed under 35 U.S.C. §119. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to an article of footwear, such as a mountain boot, and such as a mountain boot adapted for mountain racing. 
     2. Description of Background and Relevant Information 
     For an article of footwear, or for a boot, of the aforementioned type, the upper must fulfill several functions, such as the following:
         stability of the foot and of the ankle and protection against sprains, particularly on sloping or uneven terrain;   “impermeability” or protection of the boot from the exterior, particularly rain and snow, but also a mechanical protection of the foot against debris, sharp stones, or other exterior attacks;   foot comfort and, depending on the type of boot, thermal protection.       

     Traditionally, boots of this type have an external upper that is made from very thick and strong leather, lined on the inside with comfort layers such as foam materials, and having an inner coating, such as leather. 
     Such boots are very heavy and have a minimum weight of about 2.8 kg per pair, or about 6.17 lbs per pair. 
     More recently, boots have been proposed whose outer upper is in fact a plastic shell, consequently particularly rigid and impermeable, and whose comfort is ensured on the inside by a removable liner. 
     Such boots are even heavier and have a minimum weight of about 3 kg per pair, or about 6.61 lbs per pair. Furthermore, their construction is very expensive as they require at least one pair of molds per boot size. 
     Even more recently, boots have been marked having a so-called mixed upper, i.e., one in which the outer upper is constituted of a strong fabric, such as the one known under the commercial name of CORDURA®, coated with a synthetic material. 
     Such boots tend to be lighter. However, their weight is still on the order of 2.6 kg per pair, or about 5.73 lbs per pair, and, furthermore, they are not suited for use in high mountains due to their lack of rigidity. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to overcome the drawbacks of known boots and to propose a new boot construction that provides for a noticeably lightened weight for a pair of boots, while offering a good stability and protection of the foot and of the ankle and guaranteeing isothermic properties, if needed. 
     Another object of the present invention is to propose a boot modular in design, facilitating the adaptation of the construction of a boot to a particular use. 
     This object is achieved in an article of footwear that includes an upper and an outer sole, according to the invention, wherein the upper has, from the inside to the outside of the article of footwear the following:
         a comfort liner;   a frame for holding the foot and for transmitting forces, made of a substantially inextensible material and adapted to transmit the forces for tightening the foot and to hold the foot;   an outer envelope for protecting against exterior elements.       

     Such a boot construction permits the separation of the functions of comfort, holding the foot, and transmitting the forces, and protection against exterior elements over three different layers, in contrast with prior art boots in which the outer upper generally has a double function of protecting against exterior elements and of holding the foot/transmitting the forces. 
     As a result, the materials of each of the three functional “layers” of the boot can be optimized, in terms of function and weight, and one can therefore obtain a boot construction that is much lighter. 
     In this manner, the frame can be made from a very light-weight material while being selected so as to be able to transmit the forces to which this type of boot is subjected, and to ensure the desired holding/support of the foot/ankle. 
     By contrast, in the prior art, as in the case of leather boots, the material of the outer upper should be selected from a very thick, and therefore inevitably heavier leather, in order to ensure the functions for transmitting the forces and holding the foot, as well as the functions for protection against exterior elements. 
     Moreover, the separation of the functions in the boot according to the invention allow having a much more modular boot construction, in which it suffices to modify the characteristics of a functional layer to provide a boot having a completely different behavior. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The invention will be better understood, and other advantages and functional characteristics thereof will become apparent from the following description, with reference to the attached schematic drawings showing, by way of non-limiting examples, several embodiments, in which: 
         FIG. 1  is a side view of a boot according to the invention; 
         FIG. 2  is an exploded perspective view of the boot of  FIG. 1 ; 
         FIG. 3  is an exploded perspective view of the frame of the boot of  FIG. 1 ; 
         FIG. 4  is a transverse cross-sectional view of the boots of  FIGS. 1–3 ; 
         FIG. 5  is a view similar to  FIG. 4  according to another embodiment; 
         FIG. 6  is a view with a partial cut-away of the outer envelope according to one embodiment; 
         FIG. 7  is a side view of a liner-frame assembly according to a second embodiment; 
         FIGS. 8–10  are views similar to  FIG. 7  showing various embodiments of a liner-frame assembly. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1–4  show a first embodiment of the invention applied to a so-called mountain boot  1 . 
     As shown in particular in  FIGS. 1 and 2 , this boot  1  includes an upper  2 , in this case a high upper because it relates to a mountain boot, and an outer sole  3 . The upper  2  includes three different functional layers from the inside outward, namely:
         a comfort liner  10 ;   a frame  20  adapted to ensure the holding of the foot and, in the present case of a mountain boot, the ankle as well, and the transmission of forces, particularly the tightening forces;   an outer envelope  30  adapted to protect the whole boot from exterior elements.       

     In the first example, the comfort liner  10  is shown separate from the frame  20  and, consequently, the liner is removable. This type of removability is advantageous, for example, in order to dry the liner, or to allow the wearer to walk indoors while only wearing the liner, particularly in the case of mountain boots. 
     Traditionally, a liner such as liner  10  includes an upper  11 , in this case a high upper, i.e., covering the ankle, a sole  12 , and a lacing system  13 . In the present case, the lacing system  13  is substantially provided in the high portion, covering the ankle, of the upper  11  of the liner, but, as the case may be, it could also extend over the foot portion of this liner. 
     The lacing system  13  is adapted to ensure the tightening of the liner  10  about the foot/leg, particularly when the liner is removed from the frame  20 . This lacing system  13  can be replaced by a VELCRO® type closure system. The liner  10  also laterally has hooks  15  adapted to cooperate with the system for lacing the frame  20 , as further described below. 
     As is known, the liner  10  can include foam materials arranged between an inner envelope and an outer envelope. 
     In fact, the outer envelope  30  can be considered a type of gaiter, made of a flexible material, externally covering the entire frame  20  and liner and, consequently, extending from the top of the upper  2  to the bottom. 
     In the example shown, the outer envelope  30  is provided with a closure  31  of the slide fastener type. However, alternative type(s) of closures could be provided instead.  FIG. 1  shows that the flexibility of the outer envelope  30  is such that, when opened with the slide fastener  31 , it can be folded down to expose the upper extents of the frame  20  and the liner  10 . 
     The outer envelope  30  is furthermore covered at its lower end, i.e., that located just above the sole  3 , by a band  32 , i.e., a band of rubber (or similar material), peripherally glued to the envelope so as to provide additional protection against abrasion. 
     The envelope  30  is made of a material selected depending on the type of protection to be provided. 
     In the case of a mountain boot, the envelope  30  can first of all be made from an abrasion-resistant material, such as that known under the commercial name CORDURA®. 
     If impermeability were to be desired, the envelope  30  can also be lined with a layer of material that is impermeable and preferably permeable to water vapor, such as known under the commercial name GORETEX®. 
     The frame  20  includes a heel stiffener  21 , two tightening flanges  22 , arranged on the medial and lateral sides of the boot, an end piece  23 , a tongue  24 , and a sole  25 . The heel stiffener  21  encloses and surrounds not only the heel, but also the ankle. Depending on the type of boot, for example, a boot having a low upper or one sought to be more flexible, this stiffener  21  can surround only the heel portion itself of the user&#39;s foot. 
     The heel stiffener  21  is furthermore provided at its upper portion with two lacing extensions or tabs  21   a  bearing keepers  26  adapted to receive/guide a lace  27  for tightening the frame about the foot. The heel stiffener  21  has two vertical slots  21   c  adapted to soften the heel stiffener, such as making the heel stiffener more flexible, particularly more flexible in a certain area. 
     Each tightening flange  22  extends from the heel stiffener  21  and the sole  25  of the frame to the area of the user&#39;s instep girth. 
     In the case shown, each flange  22  includes a plurality of wings  22   a  extending in one direction, either substantially vertically or at an angle to the vertical, as considered with the boot supporting on a horizontal surface. Each wing  22   a  is provided at its free end with a keeper  26  adapted to receive the lace  27 . Each keeper  26  can be of the type disclosed in the document FR 2 752 683 or U.S. Pat. No. 5,906,057, for minimum bulkiness and an efficient sliding. The disclosure of U.S. Pat. No. 5,906,057 is hereby incorporated by reference thereto in its entirety, particularly for this purpose. The wings  22   a  define, with the tabs  21   a  for lacing the stiffener and the hooks  15  for lacing the liner, the zone for lacing and tightening the foot and the ankle. The hooks/guides  15  of the liner allow recovering the forces for tightening the lower leg in the area of the liner. The entire tightening system could also be attached/transferred to the frame. 
     The flanges  22  can be made from a material that is more flexible than the heel stiffener  21 , for more flexibility and a better adaptation to the volume of the foot. 
     The flanges  22  are assembled, for example, by stitches  29  to the heel stiffener  21  in an overlapping zone  28 . Each overlapping zone  28  is defined by narrow portions  21   b ,  22   b  of the stiffener and tightening flanges  22 , respectively. These respective narrow portions  21   b ,  22   b  are provided to have a sufficient length to allow two or more different boot sizes be made using the same elements  21 ,  22 , respectively, by providing for overlapping to a greater or lesser extent, whether such sizes are those according to European, Mondopoint, American or another conventional shoe sizing system. 
     The end piece  23  is a toe niece adapted to ensure the shaping of the volume in order to receive the toes and possibly, i.e., depending on the type of boot, to provide a certain protection against shocks on the toes. The end piece  23  can form one piece with the tongue  24  that extends under the entire lacing zone, so as to allow for a good distribution of the tightening pressure. In the area of its junction with the tongue  24 , the toe piece  23  has two lateral slits  23   a  to increase the flexibility of this zone and to allow a better tightening of the forefoot. Because the tongue  24  passes underneath the tightening wings  22   a , the number of keepers  26  can be reduced as the tongue distributes the forces/pressures. As a result, one obtains a better sliding of the lace through the keepers  26 , and the tightening is easier and more efficient. 
     As mentioned above, the end piece  23  has relatively narrow portions  23   b  provided to cooperate with the relatively narrow portions  22   b  of the flanges for their mutual connection by stitching  29  in an overlapping zone  28 , and these narrow portions  23   b  are provided with dimensions that are sufficiently substantial in order to be compatible with two successive boot sizes. 
     As shown particularly in  FIG. 3 , the various elements  21 ,  22 ,  23 ,  24  of the frame are made independently and then assembled together, particularly by stitches  29 . Other assembly methods, such as gluing, ultrasonic sealing, etc., can also be provided. 
     Making these elements independent allows the cost of the molds necessary for making them to be reduced, because their forms are less complicated, as well as the number of these molds, as a same assembly of these elements can enable two successive boot sizes be made. 
     Furthermore, these elements can be made from different materials, particularly with different rigidities or hardnesses. 
     By way of non-limiting-example, the elements  21 ,  22 ,  23 ,  24  can be made from polyurethane, PEBAX, and the hardness can be on the order of approximately 65–70 Shore A for the flanges  22 , and approximately 85 Shore A for the heel stiffener  21  and the end piece  23 /tongue  24 . 
     Once they are assembled together, the different elements  21 ,  22 ,  23 ,  24  of the frame are assembled to the sole  25 , for example, by a so-called strobel stitch  25   a . The sole  25  is made, for example, of PE or EVA foam, or of a felt. 
     As shown in  FIG. 4 , the assembly is then glued to the outer sole  3 , after inserting the outer envelope  30  and its band  32 . Therefore, as shown in  FIG. 4 , above a lowermost connection relative to the outer envelope, the frame  20  is separate from the outer envelope  30  above a lowermost connection relative to the outer envelope, i.e., at the sole, to separate the functions of the frame, such as supporting the foot and transmitting forces to and from the foot, from the function of the outer envelope, i.e., protecting against exterior elements. 
     In the embodiment shown in  FIG. 5 , the liner  10  is sewn at the same time as the frame  21 ,  22 ,  23 ,  24  to the sole  25 , which is then common to the two layers. 
     In this case, the liner  10  is not removable. However, the construction of the boot is more compact and lighter, and the foot is closer to the ground since there is no sole thickness. 
       FIG. 6  shows another embodiment of the outer envelope  30 , in which it includes two layers of material  33 ,  34 , respectively, namely a first outer layer  33  made of a material resisting abrasion, such as CORDURA®, and an inner layer  34 , made of an insulating foam, such as an EVA foam, in order to increase the thermal-insulation of the boot. 
       FIGS. 7–10  show various embodiments of the liner 10/frame  20  assembly, in which similar or identical elements are designated by the same reference numerals, increased by 100. 
     In the case shown in  FIG. 7 , the only difference lies in the liner  110  that has, at its upper end, in the area of the tibial base, a strap  115  adapted to cooperate with the top of the tongue  124  in order to provide additional support. Furthermore, the heel stiffener  121  of the frame  120  laterally has two vertical softening slots  121   b , as well as two cutouts  121   c  adapted in particular for adapting to the dimensions of the calf. 
     In the case of  FIG. 8 , the boot is of the mid-height type of boot, i.e., it has a semi-high upper, and the heel stiffener  221  is therefore not provided with a high portion or a tightening tab. The flange portion  222  and end piece  223  are furthermore substantially identical, and the liner  210  is also reduced in height. In this embodiment, the frame  220  does not have a tongue. The heel stiffener  221  has two softening cutouts  221   c.    
     In the case of  FIG. 9 , the boot has a high liner  310 , and is provided at its upper end with two tightening straps  315 ,  316 , respectively; but the frame  320  corresponds to a frame for a low boot, as shown in  FIG. 8 , but with a tongue  324 . In this case, the second tightening strap  316  of the liner cooperates with the upper end of the tongue  324 . Here again, the heel stiffener  321  has two softening cutouts  321   c.    
     The embodiment of  FIG. 10  corresponds substantially to that of  FIG. 8 , i.e., the boot is of the mid-height type and the heel stiffener  421  is not provided with a high portion, but has two softening cutouts  321   c , the frame  420  also not having a tongue. 
     In this embodiment, the wings  422   a  of the tightening flanges  422  are cut out by holes  422   c  for more flexibility. 
     Furthermore, the liner  410  has a single tightening tab  415 . 
     The present invention is not limited to the particular embodiments described hereinabove by way of non-limiting examples, but encompasses all constructions and equivalents that are within the scope of the following claims.