Shoe sole having a structural reinforcement therein

Abstract

A structural reinforcement in the form of an open gridwork which is advantageously used, for example, as part of a shoe sole. The structural reinforcement provides and/or enhances spring-like characteristics of the member it is reinforcing, propels and encourages the natural foot strike of the user to length the user's stride, increases the stride speed, and stabilizes the user's foot to prevent permanent compression of the midsole as a result of creep. The gridwork is impregnated throughout with a fully cured or B-stage thermosettable resin. The gridwork includes at least one continuous filament selected from the group consisting of glass, carbon, and aramid. The open gridwork is flat, corrugated, or double corrugated. The corrugated gridwork may be sinusoidal. The open gridwork may be part of a shoe midsole or may constitute a shoe midsole.

What is claimed is:  
     
         1 . A structural reinforcement comprising: 
 a corrugated structural reinforcement in the form of an open gridwork defined by strands extending in a first direction and strands extending in a second direction transverse to said first direction and being impregnated substantially throughout with a thermosettable B-stage or fully cured thermoset resin;    said strands extending in the first direction being corrugated so as to define alternating high and low portions extending across said gridwork;    said strands extending in said second direction being substantially straight so as to prevent elongation of said gridwork in said second direction;    said gridwork being resilient in a substantially vertical direction and comprising at least one continuous filament selected from the group consisting of glass, carbon, and aramid; and    said corrugated structural reinforcement having a grid height, defined by a vertical distance between an upper surface of a high portion of said gridwork and a lower surface of an adjacent low portion of said gridwork, less than 0.5 inches.    
     
     
         2 . A structural reinforcement according to    claim 1    wherein said gridwork comprises a set of warp strands and a set of weft strands disposed transversely with respect to the warp strands.  
     
     
         3 . A structural reinforcement according to    claim 2    wherein said gridwork is formed of a composite fabric.  
     
     
         4 . A structural reinforcement according to    claim 1    wherein said gridwork has a grid height which is non-uniform.  
     
     
         5 . A structural reinforcement according to    claim 1    wherein said elongation occurs in a substantially longitudinal direction.  
     
     
         6 . A structural reinforcement according to    claim 2    wherein at least some of the strands of each set are spaced apart so as to define an open structure, and wherein the set of warp strands is separated into groups each containing a plurality of contiguous strands.  
     
     
         7 . A structural reinforcement according to    claim 6    wherein at least one strand of each group lies on one side of the set of weft strands and at least one other strand of each group lies on the other side of the set of weft strands.  
     
     
         8 . A structural reinforcement according to    claim 2    wherein the sets of strands are non-interlaced.  
     
     
         9 . A structural reinforcement according to    claim 1    wherein said thermosettable resin is epoxy resin.  
     
     
         10 . A structural reinforcement according to    claim 1    wherein said resin is a thermosettable B-stage resin selected from the group consisting of epoxy, phenolic, melamine, vinyl ester, cross linkable PVC, and isophthalic polyester so as to maintain the gridwork in a semi-flexible state.  
     
     
         11 . A structural reinforcement according to    claim 2    wherein each of the strands comprises a plurality of continuous glass filaments.  
     
     
         12 . A structural reinforcement according to    claim 1    wherein said resin is a fully cured thermoset resin selected from the group consisting of epoxy, phenolic, melamine, vinyl ester, cross linkable PVC, and isophthalic polyester so as to maintain the gridwork in a relatively rigid state.  
     
     
         13 . A structural reinforcement according to    claim 1    wherein said corrugated structural reinforcement is sinusoidal.  
     
     
         14 . A structural reinforcement according to    claim 1    wherein said corrugated structural reinforcement is double corrugated.  
     
     
         15 . A structural reinforcement comprising: 
 a sinusoidal structural reinforcement in the form of an open gridwork defined by strands extending in a first direction and strands extending in a second direction transverse to said first direction and being impregnated substantially throughout with a thermosettable B-stage or fully cured thermoset resin;    said strands extending in the first direction being sinusoidal so as to define alternating concave and convex portions of said structural reinforcement;    said strands extending in said second direction being substantially straight so that elongation of said gridwork is substantially prevented in said second direction; and    said gridwork being resilient in a substantially vertical direction and comprising at least one continuous filament selected from the group consisting of glass, carbon, and aramid.    
     
     
         16 . A structural reinforcement according to    claim 15    wherein said gridwork comprises a set of warp strands and a set of weft strands disposed transversely with respect to the warp strands.  
     
     
         17 . A structural reinforcement according to    claim 15    wherein said gridwork is formed of a composite fabric.  
     
     
         18 . A structural reinforcement according to    claim 15    wherein said gridwork has a grid height, defined as a vertical distance between an upper surface of a convex portion of said gridwork and an adjacent lower surface of a concave portion of said gridwork, of less than 1.5 inches.  
     
     
         19 . A structural reinforcement according to    claim 18    wherein said grid height is less than 0.7 inches.  
     
     
         20 . A structural reinforcement according to    claim 15    wherein said gridwork has a grid height, defined as a vertical distance between an upper surface of a convex portion of said gridwork and an adjacent lower surface of a concave portion of said gridwork, which is non-uniform.  
     
     
         21 . A structural reinforcement according to    claim 15    wherein said gridwork is double corrugated.  
     
     
         22 . A structural reinforcement according to    claim 15    wherein said elongation occurs in the substantially longitudinal direction.  
     
     
         23 . A structural reinforcement according to    claim 16    wherein at least some of the strands of each set are spaced apart so as to define an open structure, and wherein the set of warp strands is separated into groups each containing a plurality of contiguous strands.  
     
     
         24 . A structural reinforcement according to    claim 23    wherein at least one strand of each group lies on one side of the set of weft strands and at least one other strand of each group lies on the other side of the set of weft strands.  
     
     
         25 . A structural reinforcement according to    claim 15    wherein said thermosettable resin is epoxy resin.  
     
     
         26 . A structural reinforcement according to    claim 15    wherein said resin is a thermosettable B-stage resin selected from the group consisting of epoxy, phenolic, melamine, vinyl ester, cross linkable PVC, and isophthalic polyester so as to maintain the gridwork in a semi-flexible state.  
     
     
         27 . A structural reinforcement according to    claim 16    wherein the sets of strands are non-interlaced.  
     
     
         28 . A structural reinforcement according to    claim 16    wherein each of the strands comprises a plurality of continuous glass filaments.  
     
     
         29 . A structural reinforcement according to    claim 15    wherein said resin is a fully cured thermoset resin selected from the group consisting of epoxy, phenolic, melamine, vinyl ester, cross linkable PVC, and isophthalic polyester so as to maintain the gridwork in a relatively rigid state.  
     
     
         30 . A structural reinforcement comprising: 
 a double corrugated structural reinforcement in the form of an open gridwork comprising a pair of gridwork elements, each defined by strands extending in a first direction and strands extending in a second direction transverse to said first direction and being impregnated substantially throughout with a thermosettable B-stage or fully cured thermoset resin;    said strands in said first direction being corrugated to define high and low portions, and said strands in said second direction being substantially straight;    said pair of gridwork elements being fixedly connected in a face-to-face relationship;    said first and second strands of said gridwork elements being oriented in like directions, respectively, and at least a portion of said high portions of one gridwork element being positioned substantially adjacent a lower surface of a portion of said low portions of the other gridwork element so as to define a cavity between said gridwork elements;    elongation of said reinforcement being substantially prevented in said second direction by said second strands; and    said structural gridwork comprising at least one continuous filament selected from the group consisting of glass, carbon, and aramid.    
     
     
         31 . A structural reinforcement according to    claim 30    wherein each of said pair of gridwork comprises a set of warp strands and a set of weft strands disposed transversely with respect to the warp strands.  
     
     
         32 . A structural reinforcement according to    claim 30    wherein each of said pair of gridwork is formed of a composite fabric.  
     
     
         33 . A structural reinforcement according to    claim 30    wherein said structural reinforcement has a grid height, defined as a vertical distance between an upper surface of a high portion of one gridwork and a lower surface of an adjacent low portion of the other gridwork, of less than 1.5 inches.  
     
     
         34 . A structural reinforcement according to    claim 33    wherein said grid height is less than 0.7.  
     
     
         35 . A structural reinforcement according to    claim 30    wherein said structural reinforcement has a grid height, defined as a vertical distance between an upper surface of a high portion of one gridwork and a lower surface of an adjacent low portion of the other gridwork, which is non-uniform.  
     
     
         36 . A structural reinforcement according to    claim 30    wherein said elongation occurs in the substantially longitudinal direction.  
     
     
         37 . A structural reinforcement according to    claim 31    wherein at least some of the strands of each set are spaced apart so as to define an open structure, and wherein the set of warp strands is separated into groups each containing a plurality of contiguous strands.  
     
     
         38 . A structural reinforcement according to    claim 37    wherein at least one strand of each group lies on one side of the set of weft strands and at least one other strand of each group lies on the other side of the set of weft strands.  
     
     
         39 . A structural reinforcement according to    claim 30    wherein said thermosettable resin is epoxy resin.  
     
     
         40 . A structural reinforcement according to    claim 30    wherein said resin is thermosettable B-stage resin selected from the group consisting of epoxy, phenolic, melamine, vinyl ester, cross linkable PVC, and isophthalic polyester so as to maintain the structural reinforcement in a semi-flexible state.  
     
     
         41 . A structural reinforcement according to    claim 31    wherein the sets of strands are non-interlaced.  
     
     
         42 . A structural reinforcement according to    claim 31    wherein each of the strands comprises a plurality of continuous glass filaments.  
     
     
         43 . A structural reinforcement according to    claim 30    wherein resin is a fully cured thermoset resin selected from the group consisting of epoxy, phenolic, melamine, vinyl ester, cross linkable PVC, and isophthalic polyester so as to interlock the strands at their crossover points and maintain the structural reinforcement in a relatively rigid state.  
     
     
         44 . A structural reinforcement according to    claim 30    wherein each gridwork of said double corrugated structural reinforcement is sinusoidal and said cavities are defined by opposing concave and convex portions of each gridwork.  
     
     
         45 . A shoe sole comprising: 
 a tread layer;    an inner sole;    a structural reinforcement in the form of an open gridwork defined by strands extending in a first direction and strands extending in a second direction transverse to said first direction wherein said strands extending in the first direction are sinusoidal so as to define alternating high and low portions and said strands extending in said second direction are substantially straight so that elongation of said gridwork is substantially prevented in said second direction, said gridwork being resilient in a substantially vertical direction and, said structural reinforcement being positioned between said tread layer and said inner sole, said gridwork comprising at least one continuous filament selected from the group consisting of glass, carbon, and aramid, said gridwork being impregnated substantially throughout with a thermosetting resin.    
     
     
         46 . A shoe sole according to    claim 45    wherein said gridwork comprises a set of warp strands and a set of weft strands disposed transversely with respect to the warp strands.  
     
     
         47 . A shoe sole according to    claim 45    wherein said gridwork is formed of a composite fabric.  
     
     
         48 . A shoe sole according to    claim 45    comprising a resilient polymer forming at least one resilient polymer cushioning layer.  
     
     
         49 . A shoe sole according to    claim 48    wherein said cushioning layer and said gridwork substantially define a midsole of said shoe sole.  
     
     
         50 . A shoe sole according to    claim 45    wherein said gridwork is corrugated.  
     
     
         51 . A shoe sole according to    claim 50    wherein said corrugated gridwork is sinusoidal.  
     
     
         52 . A shoe sole according to    claim 51    wherein said gridwork is double corrugated.  
     
     
         53 . A shoe sole according to    claim 52    wherein said double corrugated gridwork is sinusoidal.  
     
     
         54 . A shoe sole according to    claim 50    wherein said structural reinforcement imparts spring characteristics by releasing stored energy in a direction defined by a combination of a substantially vertical component and a substantially forward component.  
     
     
         55 . A shoe sole according to    claim 45    wherein said elongation occurs in the substantially longitudinal direction.  
     
     
         56 . A shoe sole according to    claim 46    wherein at least some of the strands of each set are spaced apart so as to define an open structure, and wherein the set of warp strands is separated into groups each containing a plurality of contiguous strands.  
     
     
         57 . A shoe sole according to    claim 56    wherein at least one strand of each group lies on one side of the set of weft strands and at least one other strand of each group lies on the other side of the set of weft strands.  
     
     
         58 . A shoe sole according to    claim 45    wherein said thermosettable resin is epoxy resin.  
     
     
         59 . A shoe sole according to    claim 45    wherein said resin is a thermosettable B-stage resin selected from the group consisting of epoxy, phenolic, melamine, vinyl ester, cross linkable PVC, and isophthalic polyester so as to interlock the strands at their crossover points and maintain the gridwork in a semi-flexible state.  
     
     
         60 . A shoe sole according to    claim 46    wherein the sets of strands are non-interlaced.  
     
     
         61 . A shoe sole according to    claim 46    wherein each of the strands comprises a plurality of continuous glass filaments.  
     
     
         62 . A shoe sole according to    claim 45    wherein said resin is a fully cured thermoset resin selected from the group consisting of epoxy, phenolic, melamine, vinyl ester, cross linkable PVC, and isophthalic polyester so as to interlock the strands at their crossover points and maintain the gridwork in a relatively rigid state.  
     
     
         63 . A shoe midsole comprising: 
 a resilient polymer forming at least one resilient polymer cushioning layer;    a structural reinforcement in the form of an open gridwork defined by strands extending in a first direction and strands extending in a second direction transverse to said first direction and said strands extending in said second direction being substantially straight so that elongation of said gridwork is substantially prevented in said second direction, said gridwork being positioned adjacent said at least one polymer layer to enhance spring characteristics to said polymer layer by releasing stored energy, said open gridwork comprising at least one continuous filament selected from the group consisting of glass, carbon, and aramid, said gridwork being impregnated substantially throughout with a thermosetting resin.    
     
     
         64 . A midsole according to    claim 63    wherein said gridwork comprises a set of warp strands and a set of weft strands disposed transversely with respect to the warp strands.  
     
     
         65 . A midsole according to    claim 63    wherein said gridwork is formed of a composite fabric.  
     
     
         66 . A midsole according to    claim 63    wherein said elongation occurs in the substantially longitudinal direction.  
     
     
         67 . A midsole according to    claim 63    wherein said resilient polymer cushioning layer is foamed polyurethane.  
     
     
         68 . A midsole according to    claim 63    wherein said resilient polymer cushioning layer is ethylene-vinyl acetate.  
     
     
         69 . A midsole according to    claim 63    wherein said structural reinforcement comprises a substantially linear gridwork.  
     
     
         70 . A midsole according to    claim 69    wherein said structural reinforcement is encapsulated within said resilient polymer.  
     
     
         71 . A midsole according to    claim 70    wherein said midsole is injection molded and said gridwork defines an open structure with openings substantially filled by said resilient polymer.  
     
     
         72 . A midsole according to    claim 69    wherein said resilient polymer forms a pre-formed layer defining said at least one resilient polymer cushioning layer positioned adjacent said structural reinforcement.  
     
     
         73 . A midsole according to    claim 72    wherein said resilient polymer forms a pair of said pre-formed layers positioned on opposing sides of said structural reinforcement.  
     
     
         74 . A midsole according to    claim 73    wherein each of said pair of pre-formed layers includes an outer surface configured so as to mate with the adjacent one of said pair of linear gridwork forming said structural reinforcement.  
     
     
         75 . A midsole according to    claim 72    wherein said midsole further comprises a rubber layer positioned adjacent an outer surface of structural reinforcement.  
     
     
         76 . A midsole according to    claim 75    wherein said rubber layer is positioned adjacent a bottom surface of said structural reinforcement and said pre-formed layer is positioned adjacent an upper surface of said structural reinforcement.  
     
     
         77 . A midsole according to    claim 64    wherein at least some of the strands of each set are spaced apart so as to define an open structure, and wherein the set of warp strands is separated into groups each containing a plurality of contiguous strands.  
     
     
         78 . A midsole according to    claim 77    wherein at least one strand of each group lies on one side of the set of weft strands and at least one other strand of each group lies on the other side of the set of weft strands.  
     
     
         79 . A midsole according to    claim 63    wherein said thermosettable resin is epoxy resin.  
     
     
         80 . A midsole according to    claim 63    wherein said resin is a thermosettable B-stage resin selected from the group consisting of epoxy, phenolic, melamine, vinyl ester, cross linkable PVC, and isophthalic polyester so as to interlock the strands at their crossover points and maintain the gridwork in a semi-flexible state.  
     
     
         81 . A midsole according to    claim 64    wherein the sets of strands are non-interlaced.  
     
     
         82 . A midsole according to    claim 64    wherein each of the strands comprises a plurality of continuous glass filaments.  
     
     
         83 . A midsole according to    claim 63    wherein said resin is a fully cured thermoset resin selected from the group consisting of epoxy, phenolic, melamine, vinyl ester, cross linkable PVC, and isophthalic polyester so as to maintain the gridwork in a relatively rigid state.  
     
     
         84 . A midsole according to    claim 63    wherein said structural reinforcement comprises a corrugated gridwork.  
     
     
         85 . A midsole according to    claim 84    wherein said corrugated gridwork is substantially sinusoidal.  
     
     
         86 . A midsole according to    claim 85    wherein said sinusoidal gridwork has a grid height of less than 1.5 inches.  
     
     
         87 . A midsole according to    claim 84    wherein said gridwork defines alternating high and low portions so as to define said corrugated gridwork.  
     
     
         88 . A midsole according to    claim 87    wherein each set of said gridwork defines alternating concave and convex portions so as to define said sinusoidal gridwork.  
     
     
         89 . A midsole according to    claim 84    wherein said stored energy is released in a direction defined by a combination of a substantially vertical component and a substantially forward component.  
     
     
         90 . A midsole according to    claim 85    wherein said structural reinforcement is encapsulated within said resilient polymer.  
     
     
         91 . A midsole according to    claim 85    wherein said midsole is injection molded so that each of said concave and convex portions of said gridwork are substantially filled by said resilient polymer.  
     
     
         92 . A midsole according to    claim 85    wherein said resilient polymer forms a pre-formed layer defining said at least one resilient polymer cushioning layer positioned adjacent said structural reinforcement.  
     
     
         93 . A midsole according to    claim 92    wherein said pre-formed layer includes an outer surface having a sinusoidal configuration so as to mate with said sinusoidal configuration of said gridwork.  
     
     
         94 . A midsole according to    claim 92    wherein said resilient polymer forms a pair of said pre-formed layers positioned on opposing sides of said structural reinforcement.  
     
     
         95 . A midsole according to    claim 94    wherein each of said pre-formed layers includes an outer surface having a sinusoidal configuration so as to mate with said sinusoidal configuration of said gridwork.  
     
     
         96 . A midsole according to    claim 92    further comprising pre-formed foam portions positioned beneath said convex portions of said structural reinforcement.  
     
     
         97 . A midsole according to    claim 92    wherein said midsole further comprises a rubber layer positioned adjacent an outer surface of structural reinforcement.  
     
     
         98 . A midsole according to    claim 97    wherein said rubber layer is positioned adjacent a bottom surface of said structural reinforcement and said pre-formed layer is positioned an upper surface of said structural reinforcement.  
     
     
         99 . A midsole according to    claim 64    wherein said structural reinforcement comprises a pair of substantially sinusoidal gridwork which are positioned adjacent one another so as to define a double corrugated structural reinforcement.  
     
     
         100 . A midsole according to    claim 99    wherein said gridwork defines alternating high and low portions so as to define said corrugated gridwork.  
     
     
         101 . A midsole according to    claim 100    wherein each of said gridwork define alternating concave and convex portions so as to define a double-sinusoidal gridwork.  
     
     
         102 . A midsole according to    claim 99    wherein said stored energy is released in a direction defined by a combination of a substantially vertical component and a substantially forward component.  
     
     
         103 . A midsole according to    claim 101    wherein said pair of substantially sinusoidal gridwork are positioned one above another so that crossover points are adjacent on another so as to define cavities between adjacent high and low portions of adjacent gridwork.  
     
     
         104 . A midsole according to    claim 103    comprising a polyurethane adhesive to secure said pair of said gridwork.  
     
     
         105 . A midsole according to    claim 103    wherein said structural reinforcement is encapsulated within said resilient polymer.  
     
     
         106 . A midsole according to    claim 105    wherein said midsole is injection molded so that each of said cavities are substantially filled by said resilient polymer.  
     
     
         107 . A midsole according to    claim 103    wherein said resilient polymer forms a pre-formed layer defining said at least one resilient polymer cushioning layer positioned adjacent said structural reinforcement.  
     
     
         108 . A midsole according to    claim 107    wherein said resilient polymer forms a pair of said pre-formed layers positioned on opposing sides of said structural reinforcement.  
     
     
         109 . A midsole according to    claim 107    wherein said pre-formed layer defines a sinusoidal configuration so as to mate with said sinusoidal configuration of one said pair of gridwork.  
     
     
         110 . A midsole according to    claim 108    wherein each of said pair of pre-formed layers includes an outer surface having a sinusoidal configuration so as to mate with the adjacent one of said pair of sinusoidal gridwork forming said honeycomb-shaped structural reinforcement.  
     
     
         111 . A midsole according to    claim 107    further comprising pre-formed foam portions positioned within said cavities of said structural reinforcement.  
     
     
         112 . A midsole according to    claim 107    wherein said midsole further comprises a rubber layer positioned adjacent an outer surface of said structural reinforcement.  
     
     
         113 . A midsole according to    claim 112    wherein said rubber layer is positioned adjacent a bottom surface of said structural reinforcement and said pre-formed layer is positioned adjacent an upper surface of said structural reinforcement.