Patent Publication Number: US-2002002780-A1

Title: Washable liner for footwear and a method for making such liner

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001] This application is based upon French Patent Application No. 00.08352, filed Jun. 27, 2000, 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  
       [0002] 1. Field of the Invention  
       [0003] The present invention relates to a process for manufacturing an inner liner adapted to equip an article of footwear adapted, in particular, but in a non-limiting manner, to the practice of sports. The present invention can be used for skiing, snowboarding, in-line roller skating, ice skating, mountain skiing, or other sporting activities.  
       [0004] 2. Description of Background and Relevant Information  
       [0005] In the state of the prior art, inner liners for boots and shoes generally include an outer upper adapted to provide support for the liner, and an inner lining adapted to be in contact with the foot. To adjust the inner liner to the inner volume of the boot, such as a rigid shell used in alpine skiing, in particular, wedging elements are inserted during manufacture between the upper and the inner lining of the liner, especially at the level of the ankle. These elements are fixed on the upper either by mere gluing them in place or the elements, having a self-sticking surface, are simply applied on the interior of the upper. As the wedging elements are covered by the lining, and therefore invisible, optimizing the fixing means had not been a concern, until now, for the person with ordinary skill in the art.  
       [0006] In boots, and their rigid shells in particular, the inner liners, in direct contact with the foot, are subject to the attacks from perspiration and body emanations coming from the user&#39;s foot. However, it is currently impossible to wash the liners in an efficient manner, because the gluing of the wedging elements does not resist hot water. This means that once the liner has been washed, it becomes unusable, because its internal geometry is no longer fixed and varies randomly depending on the displacement of the wedging elements.  
       [0007] In view of the state of the prior art, it would be possible to envision using glues resisting hot water, such as neoprene glue, to fix the wedging elements on the upper. However, the use of such glues requires a very long and, therefore, expensive assembly process, because the glue must be left to dry right on the elements before performing the assembly.  
       SUMMARY OF THE INVENTION  
       [0008] One of the objects of the present invention is to propose an inner liner and a process for making such inner liner for an article of footwear, such as a boot, shoe or any other foot covering, which makes it possible to wash the liner with hot water, especially in a washing machine, while preserving the positioning geometry of the wedging elements.  
       [0009] Another object of the invention is to propose an inner liner, or process of manufacturing same, that does not generate a substantial cost increase as compared to the conventional processes for making non-washable liners.  
       [0010] To achieve these objects, the liner, and manufacturing process, according to the invention comprises fixing the wedging elements on the inner surface of the upper of the liner by a mechanical means or assembly that make it possible to wash the liner in a hot fluid, at a temperature comprised in a range of 30 and 90 degrees Celsius, or substantially within such range. These mechanical assemblies among others, are of the seam assembly type, i.e., which include stitching.  
       [0011] In a first embodiment, the wedging element is sewn directly on the upper of the liner.  
       [0012] In a second embodiment, the wedging element is positioned in a pocket that is integrated in the upper of the liner. 
     
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
     [0013] The invention will be better understood and other advantages thereof will become apparent from the description that follows, with reference to the annexed drawings. The description illustrates, by way of non-limiting examples, certain preferred embodiments.  
     [0014]FIG. 1 schematically shows a cross-section of the liner along its thickness in a first embodiment of the invention.  
     [0015]FIG. 2 shows a front view of the interior of the upper, obtained according to the first embodiment, before it is assembled on the sole of the liner, a portion of FIG. 2 being broken-away in the area of the lining.  
     [0016]FIG. 3 shows a side view of the liner obtained according to the first embodiment.  
     [0017]FIG. 4 shows a front view of the interior of the upper according to a second embodiment of the invention, and before it is assembled on the sole of the liner.  
     [0018]FIG. 5 schematically shows a cross-section along the thickness of the material used for making the liner.  
     [0019]FIGS. 6 a,    6   b,    6   c  schematically show a cross section of the liner along its thickness according to various alternatives of the first embodiment. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
     [0020]FIG. 1 shows a cross section along the thickness of the inner liner CH, in the area of the upper O, made according to the present manufacturing process. The inner liner CH includes a lining  1 , adapted to be in contact with the foot P, in the area of the inner surface  1   a  of the lining. On the opposite side, the outer surface  1   b  of the lining  1  is opposite the inner surface Oa of the upper  0 . Because this lining  1  is adapted to provide comfort upon contact with the user&#39;s foot P, it is generally constituted of a foam type soft material, whereas the upper O, which is adapted to provide the inner liner with a certain rigidity, is constituted of a harder material which can also be of the foam type.  
     [0021] To better adjust the inner liner CH to the geometry of the foot P, at least one wedging element  20  is inserted during manufacture between the upper O and the lining  1 . This wedging element  20  is fixed by a mechanical means  3  on the upper O. A mechanical means  3  here encompasses any mode/method of mechanical assembly, possibly associated with a chemical assembly, without any supplemental chemical adhesive.  
     [0022] The mechanical assembling means include, in particular, seams/stitching, rivets, and/or the self-gripping assembly, i.e., hook and loop fastening assembly, more commonly known by the commercial name “Velcro.” The mechanical means associated with a chemical assembly without adhesive include, in particular, co-injection, heat welding, vibration/friction welding and welding by molding. These latter means produce a mechanical assembly by closely imbricating the two materials to be assembled by a very localized heating at the contact zone of the portions to be assembled. This mechanical assembly is then reinforced by chemical-type molecular linkages that occur spontaneously and naturally between the two materials in the area of the mechanical imbrication zone.  
     [0023] This fairly broad set of assembly means indeed makes it possible to achieve the objects of the present invention, namely, the capability that the liner can be washed in a hot fluid without deteriorating the assembly means, and limiting increases in the liner production cost.  
     [0024] Furthermore, nowadays, the user who wishes to wash the liner will spontaneously put it in a washing machine which uses a hot fluid, in particular water, whose temperature is mainly comprised in a range of about 30 and 90 degrees Celsius.  
     [0025] The purely mechanical assembly means remain inexpensive and resist temperatures of 90 or even 100 degrees Celsius, without any problem, on the one hand; and the mechanical means, completed by chemical linkages, as described hereinabove, remain inexpensive, because they do not require the addition of a supplemental adhesive, such as glue, on the other hand. These means also resist a hot fluid, whose temperature is lower than the heating temperature used for the assembly, a temperature at which the chemical linkages are set in place. Indeed, the wedging elements  20  are generally made of a polyethylene foam whose melting temperature is about 110 degrees Celsius, or polypropylene foam which melts at a temperature of about 130 degrees Celsius.  
     [0026] In the preferred embodiment shown in FIG. 1, the mechanical means  3  is a seam or stitched assembly.  
     [0027] In FIG. 2, the upper O, which has not yet been assembled on the sole, is shown on its inner surface Oa. The upper O is covered by the lining  1  on its right portion, whereas on its left portion, the liner  1  is shown laid open so as to show the wedging element  20 . The wedging element  20  is advantageously positioned on the upper O in the area of the ankle so that the rear of the foot is kept enclosed in the inner liner, and is assembled on the inner surface Oa of the upper O by mechanical means  3   x,    3   y,    3   z,  which resist a hot fluid.  
     [0028] Because the mechanical means  3   x,    3   y,    3   z,  such as seams/stitching, only serve to maintain the wedging element  20  in position on the upper O, they do not need to extend over the entire periphery of the wedging element  20 . The means can be advantageously arranged in a localized fashion on one position of the periphery, such as the seam  3   x,  or in the middle of the wedging element  20 , such as the seam  3   z,  or superimposed on a seam  100  for assembling the upper O, such as the seam  3   y.    
     [0029] Moreover, the wedging element  20  can be fixed on the lining  1  by mechanical means  3   w,  such as seams/stitching, which are hot fluid resistant. Advantageously, this seam can attach the wedging element  20  to the lining  1  as well as to the upper O by extending right through the three thicknesses. Respecting this constructional arrangement makes it possible to better maintain the shape of the lining of the liner, in addition to the conventional means for assembling the lining on the upper, which are generally located on the periphery of the upper, in particular in the area of the zones of assembly of the upper O on the sole of the liner.  
     [0030] If the fixing means  3   x,    3 y,  3   z,    3   w,  are purely mechanical means, such as seams/stitching, it is necessary to pre-position the wedging element  20  on the inner surface Oa of the upper O, and to maintain it in position on the upper during assembly. One way to proceed includes gluing the wedging element with a glue that is not particularly hot water resistant. This glue only serves to maintain the wedging element  20  in place on the upper O while the seam is being made. Then, when the liner made up according to this manufacturing process is washed for the first time, the wedging element  20  is no longer maintained on the upper O by the glue, which is rendered inefficient by the hot water, but only by the seams  3   ,    3   y,    3   z,    3   w.    
     [0031]FIG. 3 shows the liner CH obtained by assembly of the upper O on the sole  60 . The seams  3   x,    3   y,    3   z,  which fix the wedging element  20  on the upper O from within the liner, are then apparent. Therefore, it is interesting to limit the fixing seams, in particular for aesthetic purposes. In addition, these seams constitute a potential abrasive point on the outer surface Ob of the upper O.  
     [0032]FIG. 4 shows a second embodiment where the wedging element  21  is housed, during the manufacturing process, in an internal pocket  10  located on the inner surface Oa of the upper O. Thus, the wedging element  21  is positioned so as to be inserted between the upper O and the lining  1 . The pocket  10  includes an opening  62  located on its upper edge. Thus, during the practice of the sport, and despite the effect of gravity, the wedging element  21  does not have the tendency to come out of the pocket  10  spontaneously.  
     [0033] Advantageously, the pocket  10  is provided with a flap  61  covering the opening  62  in the closed position. Moreover, this flap  61  can include closure means, especially of the self-gripping type, i.e., hook-and-loop fasteners.  
     [0034]FIG. 5 shows constructional details, with respect to the materials used, either for the upper, the lining, or the wedging element, so that the materials themselves are not deteriorated, when immersed in a hot fluid, during the washing of the liner.  
     [0035] The materials  14  mainly used are more or less thick foams which include cavities  15  filled with a fluid, especially air. If the cavities  15  are not sealed, the fluid can escape and be replaced by the washing fluid. In this case, the material  14 , impregnated with the washing fluid, becomes very heavy and difficult to dry. Furthermore, due to its weight, this fluid can irremediably deform the foam. Therefore, most of the cavities  15  of the material  14  must be sealed.  
     [0036] Moreover, the material  14  must intrinsically resist the washing temperature of the hot fluid in the range, of substantially within the range of about 30 to 90 degrees Celsius.  
     [0037] Certain materials used, either for the upper, or for the lining, are made of multi-layered materials  16 . This makes it possible to associate with a material  14 , of the foam type as described previously, at least one external layer  70 ,  71 , which, due to its property, differs from the material  14 . The material  14  of the upper can be advantageously associated with an external layer  70 , positioned outside the liner, which has a good resistance to abrasion, such as textiles of the polyamide or polyurethane type. Similarly, the material  14  of the lining can be advantageously associated with an outer layer  71 , positioned within the liner, which procures an agreeable contact for the skin, and which is anti-allergic.  
     [0038] The previously described multi-layered material  16  can be obtained during manufacture, in the area of the stratification, by mechanical means  72  which resist separation in the washing hot fluid. These mechanical means  72  are consistent with those described previously, and especially heat welding, subject to compatibility between the materials to be assembled. Indeed, this compatibility between the materials enables the spontaneous and natural setting of the chemical linkages at the molecular level as previously described.  
     [0039] Another embodiment, not shown, comprises using a co-injection process to fix the wedging element to the inner surface of the upper. This means that the constituent material of the wedging element is injected in a mold almost simultaneously with the constituent material of the upper. The two chemically compatible materials are closely mixed in the area of their contact zone, for they are melting. The mechanical fastening obtained during the cooling is reinforced by the establishment of natural chemical linkages due to the chemical compatibility of the two materials.  
     [0040] A superinjection process can also be used. The constituent material of the wedging element is injected on the material of the upper which has more or less cooled off. Upon contact with the injected material, which is hot, the material of the upper melts locally, in the area of the contact zone, which ensures a mechanical fastening by locally mixing the two materials. This fastening is then reinforced by natural molecular chemical linkages due to the chemical compatibility of the two materials.  
     [0041]FIGS. 6 a,    6   b,    6   c  show alternative constructions, related to the first embodiment, which specify various means making it possible to fix the wedging element  20  to the upper O by sewing, without damaging the wedging element  20 . Indeed, if the wedging element  20  is made out of a material that is not mechanically very resistant, the seam  3  runs the risk, over the short or long term, of shearing the wedging element  20  which will then separate from the upper O during washing. The seams  3  shown in FIGS. 6 a,    6   b  correspond to the seams  3   x,    3   y,    3   z  referred to previously.  
     [0042] In FIG. 6 a,  the wedging element  20  is attached to the upper O and inserted between the upper O and the lining  1 . However, the wedging element  20  used is specific so as to have at least one layer  80  of greater resistance, to tearing and shearing in particular, which prevents the seam  3  from passing through. The wedging element  20 , currently shown, includes a resistant layer  80  fixed by appropriate means to a volume layer  81 . The resistant layer  80  here is arranged on the inner surface Oa of the upper O.  
     [0043] A reverse arrangement, in which the volume layer  81  is positioned on the inner surface Oa and the resistant layer  80  is positioned opposite the lining  1 , remains consistent with the invention.  
     [0044] The wedging element  20  of the multi-layered type can be obtained in several ways, including the following. First, the multi-layered element can be made by associating chemically compatible materials according to fixing means, such as co-injection, superinjection, or heat welding, described previously in FIG. 5. The resistant layer  80  can have a certain thickness, especially if it is made of a foam type material. But the resistant layer  80 , whose thickness can also be negligible, can be made of a woven or non-woven textile material.  
     [0045] Furthermore, the multi-layered wedging element  20  can be made by assembling at least two layers, such as the resistant layer  80  and the volume layer  81  by a seam/stitching. This seam, which is not shown in the figures, is separate from the seam  3  serving to mount the footwear.  
     [0046] In this first alternative construction, the lining  1  remains separate from the upper O/wedging element  20  assembly, in the area of the seam  3 .  
     [0047] In FIG. 6 b,  the wedging element  20  is fixed to the upper  20  and inserted between the upper O and the lining  1 . However, the wedging element  20  is maintained, in the area of the seam  3 , between the upper O and a seam reinforcement  82  that is arranged opposite the lining  1 . This seam reinforcement  82  is advantageously localized around the seam  3  and made of a resistant textile material. In this second alternative construction, the seam  3  keeps the wedging element  20  attached on the upper O, and the lining  1  remains separate from the upper O/wedging element  20  assembly in the area of the seam  3 .  
     [0048] In FIG. 6 c,  the wedging element  20  is simultaneously fixed to the upper O and to the lining  1  by a seam  3 . This seam  3 , which extends through the upper O, the wedging element  20 , as well as the lining  1 , corresponds to the seam  3   w  referred to previously.  
     [0049] In this third alternative construction, the lining  1  must have enough technical characteristics so that the seam  3  does not tear the lining  1 . However, the lining  1  must also have comfort characteristics since it is in direct contact with the foot. The association of these two characteristics, which are a priori contradictory, can be obtained by using, for the lining  1 , a multi-layered material of the type described in FIG. 5. Thus, the lining  1  advantageously includes a resistant layer, preferably located on the outer surface  1   b,  which is associated with a comfort layer located preferably on the inner surface  1   a  of the lining  1 .  
     [0050] Thus the wedging element  20 , used for the alternative constructions shown in FIGS. 6 b  and  6   c,  does not need specific characteristics related to the resistance of the seam.  
     [0051] The present invention is not limited to the embodiments described hereinabove, which are provided for guidance only, but encompasses all similar or equivalent embodiments.