Patent Publication Number: US-2003226280-A1

Title: Textile-soled footwear

Description:
RELATED APPLICATIONS  
     [0001] This application claims priority to U.S. Provisional Application Ser. No. 60/372,463 and U.S. Provisional Application Ser. No. 60/372,464, both filed Apr. 12, 2002. 
    
    
     
       FIELD OF THE INVENTION  
       [0002] This invention relates to footwear and, in particular, to footwear having a textile-layered outsole.  
       BACKGROUND  
       [0003] Footwear components can be joined by any number of well-known methods, including, but not limited to, stitching by hand or machine, adhesives, vulcanization, and injection molding. The method of joining can affect many aspects of the footwear, including durability and cost of manufacture.  
       [0004] While joining footwear components by stitching is capable, depending on the type of components to be joined, of producing a durable product, it can be a time consuming and costly method of footwear fabrication, requiring many separate steps. The manufacture of footwear with components joined by adhesives can be much more economical, but the resulting product is frequently not particularly durable, with components often separating over time due to factors such as repeated flexing, abrasion, or exposure to moisture. Footwear with vulcanized or moldably attached components and layers is more durable, in that the layers and/or components are more firmly joined and much less likely to separate over long use. It is also generally more economical and quicker to manufacture than footwear manufactured by stitching. Further, components or layers that are actually made from moldable materials tend to be particularly resilient, durable, and flexible.  
       [0005] The join between a footwear upper and outsole is a stress point particularly prone to separation and/or tearing. The outsoles themselves must also be able to withstand a lot of wear and tear, from both ground contact and flexing during use. For this reason, ground-contacting textile outsole layers that are not firmly attached over their entire upper surface to an overlying supporting layer are particularly prone to tearing and separation from the shoe.  
       [0006] The construction of footwear outsoles determines many important characteristics of the footwear, such as durability, flexibility, comfort, stability, foot support, and slip resistance. For example, the shape and composition of the outsole particularly affect slip resistance. Footwear articles with textile soles, especially those that do not have a supporting layer, are generally not slip resistant because they tend to have a smooth surface with no way to provide treads to improve traction. They also are not very durable, particularly if subjected to outdoor walking conditions. Further, the lack of support they provide can be uncomfortable on uneven surfaces such as gravel or decking, as well as for persons needing more arch or foot support. Provision of a midsole board between the textile outsole and an inner sole to improve comfort on uneven surfaces is sometimes attempted, but it complicates fabrication of the footwear, may render it less durable, and frequently reduces comfort on normal surfaces. Provision of a molded-type outsole layer to which a ground-contacting textile layer is adhesively attached is more successful, but the resulting outsole is prone to the layer separation problem discussed earlier.  
       [0007] What has been needed, therefore, is an article of textile-soled footwear wherein all outer components, including the upper and the ground-contacting textile layer, are moldably attached to an outsole made of moldable or moldable-type material.  
       OBJECTS OF THE INVENTION  
       [0008] Accordingly, an object of the present invention is to provide an article of footwear having a textile layer at the ground-contacting surface of the outsole.  
       [0009] A particular object of the invention is to provide a textile-soled article of footwear that is durable when worn on outside-type surfaces.  
       [0010] A further particular object of the present invention is to provide a textile-soled article of footwear that is durable despite repeated flexing.  
       [0011] Another particular object of the invention is to provide a textile-soled article of footwear that is slip-resistant.  
       [0012] Yet another particular object of the invention is to provide a textile-soled article of footwear that has a flexible but shape-retaining outsole.  
       SUMMARY  
       [0013] These and other objectives are met by the present invention, which is an article of footwear having an upper moldably attached to an outsole comprising a textile layer moldably adhered to an outsole layer at the ground-contacting surface. In the preferred embodiment of the invention, this entire “outer shell” of the footwear article is simultaneously assembled during a single injection molding process; however, any other suitable method or apparatus known in the art for moldably attaching footwear, such as vulcanization, may also be used.  
       [0014] In one embodiment of the present invention, the article of footwear has an upper and a unit-molded rubber or plastic sole covered with textile at the ground-contacting surface, providing the article of footwear with a flexible but shape-retaining textile-covered outsole. In a preferred embodiment, the molded outsole layer is made from thermoplastic resin. In an alternate embodiment, the outsole is cut, rather than molded, from moldable or moldable-type, water-resistant materials. The textile-layered sole of the footwear of the present invention is an “indoor-outdoor” sole, having a textile ground-contacting surface but still being rigid and durable enough for use on outdoor-type surfaces such as driveways, decking, cement floors, and gravel.  
       [0015] The textile employed for the ground-contacting textile layer in the present invention can be any natural or man-made textile, but in the preferred embodiment is a combination of cotton, polyester, and Lycra While, in a preferred embodiment, the upper is a textile made of natural or man-made fibers, any other type of upper known in the art that is capable of being moldably attached would be suitable. In a preferred embodiment of the present invention, both the footwear upper and the ground-contacting textile outsole layer are integrally embedded in the outsole layer.  
       [0016] It is important to the present invention that the ground-contacting textile outsole layer be moldably attached to the outsole. Integral attachment of the textile-covered outsole provides one of the significant advantages of the present invention, which is prevention of tearing of the ground-contacting textile outsole layer and/or separation of the textile outsole layer from the outsole.  
       [0017] In one embodiment, the outsole layer extends around the side of the shoe, moldably attaching to the upper across a large width. This greatly increases the footwear durability because of the large area of attachment between the outsole layer and the upper, making separation of the outsole and the upper unlikely.  
       [0018] In a preferred embodiment of the invention, the outsole has treads to which the textile outsole layer is moldably conformed. These treads can be laid out in any desired pattern and provide improved slip resistance. With use, the ground-contacting textile outsole layer may wear away from the ground-contacting surfaces of the treads, which will generally increase slip resistance. An important feature of the present invention is that, because the ground-contacting textile outsole layer and the outsole are integrally connected together, this wearing away does not cause tears in the ground-contacting textile outsole layer or separation of the textile outsole layer from the outsole. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0019]FIG. 1 is an enlarged cross section of an article of textile-soled footwear according to an embodiment of the present invention;  
     [0020]FIG. 2 is a bottom view of two articles of textile-soled footwear according to an embodiment of the present invention;  
     [0021]FIG. 3 is a side view of an article of textile-soled footwear according to an embodiment of the present invention; and  
     [0022]FIG. 4 is a magnified cross section of a piece of the outsole of an article of textile-soled footwear according to an embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION  
     [0023] The present invention is an article of footwear with an outer sole having a moldably attached upper and a textile layer that is moldably adhered to an outsole layer at the ground-contacting surface. In the preferred embodiment of the invention, the entire outer shell of the footwear article is simultaneously assembled during a single injection molding process, such as the process and apparatus disclosed in copending U.S. patent application entitled  Injection - Molded Footwear Having a Textile - Layered Outer Sole,  also filed Apr. 14, 2003. However, any other suitable method or apparatus known in the art, including, but not limited to, vulcanization, may also be used. The moldable attachment of the upper and the ground-contacting textile layer to the outsole provide a far more durable article of footwear than those having ground-contacting textile layers and/or uppers attached by other methods, such as stitching or adhesives.  
     [0024] In one embodiment of the present invention, the article of footwear has an upper and a unit-molded rubber or plastic sole covered with textile at the ground-contacting surface. In the preferred embodiment, the molded outsole layer is made of a thermoplastic resin, which is preferred because of the ability of such resins to be hardened and melted more than once. However, any material suitable for molding and capable of bonding to the materials selected for the upper and the textile layer, such as rubber, latex, or many elastomeric polymers would be suitable. In an alternate embodiment, the outsole is cut, rather than molded, from moldable-type water-resistant materials. The textile-layered sole of the footwear of the present invention is intended to be an “indoor-outdoor” sole, having a textile ground-contacting surface but still being rigid and durable enough for use on outdoor-type surfaces such as driveways, decking, cement floors, and gravel. The present invention is particularly applicable to the construction of slippers, but many other kinds of footwear may benefit from the principles of the invention.  
     [0025] The textile employed for the ground-contacting textile layer in the present invention can be any natural or man-made textile. However, certain textiles perform better than others during use and during the chosen manufacturing process, so the options should be carefully evaluated for texture, thickness, stretchability, heat resistance, and density. In the preferred embodiment of the invention, the textile utilized is a combination of cotton, polyester, and Lycra®, most frequently in the ratio: 10% cotton, 70% polyester, and 20% Lycra®. This combination is durable and is also capable of providing sufficient stretchability that the fabric can be pulled flat and held very tightly over the sole plate during the injection molding process utilized to fabricate the preferred embodiment of the present invention.  
     [0026] The thickness of the chosen textile is also important. Too thick a textile may cause failure of the manufacturing process, or of conformance to the desired shape of the molded outsole. Too thin a textile may not withstand the manufacturing process. In the preferred embodiment of the invention, the optimum thickness has been determined to lie between 0.29 and 0.31 mm. The textile normally utilized for this embodiment has a thickness of 0.3 mm. The textile chosen should also have heat resistance sufficient that the textile can maintain its integrity during the manufacturing process. It has been determined empirically for the preferred embodiment that a heat resistance of 174.5 to 185.5 degrees Centigrade is optimum. In the preferred embodiment, the textile normally utilized has a heat resistance of 180 degrees Centigrade.  
     [0027]FIG. 1 is a cross section of an article of textile-soled footwear according to an embodiment of the present invention. As shown in FIG. 1, upper  100  is embedded in outsole layer  110 , as is ground-contacting textile outsole layer  120 . While in a preferred embodiment upper  100  is a textile made of natural or man-made fibers, any other type of upper known in the art, including, but not limited to, leather, rubber, and plastic, would be suitable for use in the present invention.  
     [0028] In a preferred embodiment, outsole layer  110  extends around the side of the shoe, moldably attaching to upper  100  across a large width. This gives the outsole layer  110  a foxing-like appearance and greatly increases the footwear durability because of the large area of attachment between outsole layer  110  and upper  100 . Separation of the outsole and the upper are therefore extremely unlikely in this embodiment.  
     [0029] It is important to the present invention that ground-contacting textile outsole layer  120  be moldably attached to outsole layer  110 . Integral connection of the textile-covered outsole provides one of the significant advantages of the present invention, which is prevention of tearing of the ground-contacting textile outsole layer and/or separation of textile outsole layer  120  from outsole layer  110 . Optional treads  130  are also shown, to which textile outsole layer  120  is moldably conformed.  
     [0030] Outsole layer  110  has optional air pockets  140  on its inner surface, providing for increased flexibility of the sole. An optional inner sole  150  of any of the many constructions known in the art may be provided, as may any of the many types of padding, support devices, and/or orthotics known in the art. Similarly, an optional inner lining  160  may be added, with or without added padding or support devices.  
     [0031]FIG. 2 is a bottom view of two articles of textile-soled footwear according to an embodiment of the present invention, having upper  100  moldably attached to outsole layer  110 , which is integrally molded to textile outsole layer  130 . In a preferred embodiment of the invention, outsole layer  110  has treads  130  in the form of bumps, ridges, or other types of protrusions, to which textile outsole layer  120  is moldably conformed. These treads can be laid out in any desired pattern and provide improved slip resistance. With use, ground-contacting textile outsole layer  120  may wear away from the ground-contacting surfaces of treads  130 , which will generally increase slip resistance. An important feature of the present invention is that, because ground-contacting textile outsole layer  120  and outsole layer  110  are integrally connected, this wearing away does not cause tears in ground-contacting textile outsole layer  120  or separation of textile outsole layer  120  from outsole layer  110 . Any type of pattern, design, label, or similar device, such as label  200  and decorative seam detail  210  shown in the embodiment of FIG. 2, may also be present on any desired surface of the outsole.  
     [0032]FIG. 3 is a side view of an article of textile-soled footwear according to an embodiment of the present invention, showing upper  100  moldably attached to outsole layer  110 , with optional decorative seam detail  210 . The textile-soled footwear shell is ready for whatever additions may be desired, including, but not limited to, fasteners, linings, padding, inner sole, orthotics, labels, and trims.  
     [0033]FIG. 4 is a magnified cross section of a piece of the outsole of an article of textile-soled footwear according to an embodiment of the present invention. Ground-contacting textile outsole layer  120  is integrally embedded in outsole layer  110  at fusion zone  400 , an area of textile outsole layer  120  which has been infiltrated by “fingers”  410  and droplets  420  of the moldable or moldable-type material making up outsole layer  110 . Fusion zone  400  is therefore the operable source of the moldable attachment of textile outsole layer  120  to outsole layer  110 .  
     [0034] The present invention, therefore, provides an article of footwear having a textile layer at the ground-contacting surface of the outsole. This textile-soled article of footwear is durable when worn on outside-type surfaces, is slip-resistant, has a flexible but shape-retaining outsole, and is durable despite repeated flexing. Each of the various embodiments described above may be combined with other described embodiments in order to provide multiple features. Furthermore, while the foregoing describes a number of separate embodiments of the apparatus and method of the present invention, what has been described herein is merely illustrative of the application of the principles of the present invention. Other arrangements, methods, modifications and substitutions by one of ordinary skill in the art are therefore also considered to be within the scope of the present invention, which is not to be limited except by the claims that follow.