Direct attach footwear construction

Abstract

A shoe construction having an outsole direct attached to a midsole with a mechanical interlock. The outsole includes a bottom and a wall extends upwardly therefrom, optionally around the entire periphery of the outsole. At a pre-selected distance above the bottom, a rib or a plurality of protrusions extend inwardly from the wall so that a void is defined between the protrusions and the bottom. The midsole is direct attached to the upper, the bottom, the wall and the protrusions. The protrusions enhance the mechanical securement of the midsole to the outsole. To assemble the construction, the outsole and the upper are positioned in a mold a pre-selected distance apart to form a cavity. A plastic material is injected into the cavity and direct attaches to the outsole and upper. As the plastic material fills the cavity, it seeps into the void defined between the projections and the upper surface.

Description

BACKGROUND

[0001] The present invention relates to a footwear construction, and more particularly to a footwear construction including a direct attach outsole.

[0002] The footwear industry has developed many shoe constructions that are both durable and aesthetically pleasing. One such sole construction is referred to as the welt construction. There are a variety of popular welt constructions, however, in each, a "welt," for example, a strip of material such as leather or rubber, connects an upper to an outsole to form the footwear. The welt generally includes a horizontal base from which upward and downward ribs extend. The upwardly extending rib is stitched to the upper and the downwardly extending rib or the base is stitched to the sole to hold the upper and outsole together. The welt itself is semi-rigid or hard to withstand the forces exerted through the stitching. In the finished shoe, the welt provides an aesthetically pleasing transition between the sole and upper.

[0003] Although the welt construction is durable and aesthetically pleasing, the welt and associated stitching compromises the flexibility of the shoe. This is true even in welt constructions where the sole is a hollow shell filled with a flexible polyurethane foam material. Furthermore, the inclusion of the welt in welt construction footwear increases the cost of and the time required to manufacture such footwear.

[0004] In an effort to improve the flexibility of footwear, several sole constructions have been developed that direct attach the sole to the upper with a midsole. These constructions are significantly different from and unrelated to welt constructions because they eliminate a need for a welt altogether and rely on a very different construction to hold the upper and sole together. As shown in FIG. 1, a typical direct attach construction 100 includes a wearing sole 110 direct attached to a flexible polyurethane midsole 120, which is in turn direct attached to an upper 130. The wearing sole includes a flat, featureless surface 112 to which the polyurethane midsole is secured via gluing or by molding the polyurethane over the surface 112 during manufacture of the shoe. Although this direct attach construction is flexible and resilient, it is not sufficiently durable because the wearing sole 110 is prone to detach from the midsole 120, particularly in the toe region as shown in FIG. 2. In some cases, the sole detaches completely from the midsole which can cause injury to the wearer, especially if he or she is engaged in strenuous activity.

SUMMARY OF THE INVENTION

[0005] The aforementioned problems are overcome in the present invention wherein a direct attach construction is provided that includes an outsole direct attached to a midsole with a mechanical interlock. The outsole includes one or more protrusions extending inwardly from a wall extending around the periphery of the outsole. These protrusions are surrounded by and/or encapsulated by the plastic material from which the midsole is constructed to create the mechanical interlock.

[0006] In a preferred embodiment, the midsole is constructed from a plastic material, for example polyurethane, which encapsulates and intersecures to the multiple protrusions to increase the mechanical strength of the direct attach bond between the outsole and the midsole.

[0007] In a more preferred embodiment, the outsole includes an upper surface and a tread pattern opposite therefrom. The upper surface is bounded by the peripheral wall and located below the protrusions a pre-selected distance to define a void. The plastic material of the midsole seeps into the void and around the protrusions to fully encapsulate the protrusions.

[0008] In an even more preferred embodiment, a portion of the tread pattern is reflected through to the upper surface of the outsole to increase the surface area thereof and further increase the strength of the direct attach bond between the outsole and the midsole.

[0009] The present invention also provides a method for manufacturing footwear including the steps of: (a) providing an outsole including a wall extending around the periphery of the outsole and one or more protrusions extending inwardly toward the center of the outsole from the peripheral wall; (b) positioning an upper a pre-selected distance above the outsole; (c) positioning a mold adjacent the upper and the peripheral wall to define a midsole cavity; and (d) introducing plastic material into the cavity to form the midsole of the shoe and direct attach the midsole to both the outsole and the upper, wherein the molding material encapsulates the protrusions of a outsole to provide a mechanical interlock between the midsole and outsole.

[0010] The present invention provides a durable and comfortable sole construction. Because the present invention direct attaches an outsole to an upper, rather than securing the outsole to the upper with a welt, the construction is very flexible and resilient. The use of a plastic material, such as polyurethane, to direct attach the outsole to the upper also makes the outsole lighter than welt constructions. Additionally, the mechanical interlocking of the midsole to the outsole enhances the strength of the direct attach bond between the midsole to the outsole. This interlock prevents delamination of the outsole from the midsole, making the construction very durable.

[0011] These and other objects, advantages and features of the invention will be more readily understood and appreciated by reference to the detailed description of the invention and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG. 1 is a sectional view of a direct attach sole construction according to the prior art;

[0013] FIG. 2 is a perspective view of a delaminated direct attach sole construction according to the prior art;

[0014] FIG. 3 is a sectional view of an article of footwear incorporating the sole construction of the present invention;

[0015] FIG. 4 is an exploded perspective view of the article of footwear;

[0016] FIG. 5 is a top perspective view of an outsole of the present invention; and

[0017] FIG. 6 is a sectional view of the article of footwear in a molding operation.

DETAILED DESCRIPTION OF THE INVENTION

[0018] A boot constructed in accordance with a preferred embodiment of the present invention is shown in FIGS. 3 and 4, and generally designated 10. For purposes of disclosure, the present invention is described in connection with a three-quarter height boot, however, the present invention is well-suited for use with other types of soled, un-welted footwear.

[0019] In general, the boot 10 includes an outsole 20 that is direct attached to a midsole 40, which is direct attached to an upper 50. As best shown in FIG. 5, the outsole 20 includes a peripheral wall 22, from which one or more protrusions 24 extend inwardly formed the center of the outsole. The midsole material 40 surrounds the protrusion 24 (FIG. 3) to mechanically interlock the outsole 20 and midsole 40.

[0020] The upper 50 is generally conventional and will not be described in detail. Suffice it to say that the upper 50 includes a quarter 52, a vamp 54, and a backstay 56. The upper 50 terminates in a lower peripheral edge 58 that is direct attached to the midsole 40 as described in detail below. The upper 50 is preferably manufactured from leather, canvas, nylon or other suitable materials, and may include a liner (not shown) or other conventional accessories.

[0021] The outsole 20 is manufactured from a relatively hard rubber or other sufficiently durable and wear-resistant material. The bottom 26 includes an upper surface 32 and an outer surface 34. The outer surface 34 forms the wearing surface of the outsole 20 and is contoured to define the desired heel and tread pattern. The outer surface 34 may be textured to improve the traction and aesthetic appeal of the boot. Optionally, the upper surface 32 may be textured. The tread pattern of the outer surface 34 may reflect through the bottom 26 so that recesses corresponding to portions of the tread pattern are defined in the upper surface 32. If desired, the outsole 20 may also include a shank (not shown), a filler (not shown) or other conventional sole components.

[0022] The outsole 20 also includes a peripheral wall 22 extending upwardly from the periphery of the bottom 26. The peripheral wall 22 includes an interior 23 and an exterior 25. The exterior 25 of the peripheral wall 22 may be contoured or textured to provide the desired visual appearance of the outsole of the interior 23 may also be textured as desired. The peripheral wall 22 further includes multiple protrusions 24 extending inwardly near the upper edge of the interior 23 of the peripheral wall 22. As shown, the protrusions 24 are circular sections, however other shapes may be substituted as desired. The protrusion(s) also may collectively form a rib, with or without indentations, as desired. As used herein, protrusion may also include a rib. The protrusions are separated from the upper surface 32 a pre-selected distance 23 to cooperatively define a void between the protrusions and the upper surface. The material protrusions 24 interlock with the midsole material 24 to improve the mechanical interconnection of the midsole and outsole. Optionally, the protrusions 24 define apertures (not shown) through which the midsole 40 extends to further improve the interconnection of the outsole and midsole.

[0023] The midsole 40 preferably is constructed from a resilient and flexible polyurethane. The uppermost portion of the midsole is direct attached to the peripheral edge 58 of the upper, and optionally any insole 60 included in the boot. The midsole 40 preferably includes an exterior wall 42 that may be textured to provide a desired appearance or function in the completed boot. Optionally, the midsole exterior wall 42 and wall exterior 25 co-terminate together on the outside of the shoe.

[0024] The lowermost portion of the midsole define a peripheral groove 44. This peripheral groove conforms to the protrusions 24, and where the midsole 40 is direct attached to the outsole 20, the portion of the midsole in the peripheral groove substantially encapsulates the surrounds the protrusions 24. Below the groove 44, the midsole includes a base 46, which itself is direct attached to the upper surface 32 of the outsole. Preferably, the base intrudes or seeps into the void defined between the protrusions 24 and the upper surface 32 to substantially occupy or fill that void. Where the upper surface of the sole 20 includes recesses 28 reflected therein, the midsole 40 substantially fills those recesses as well.

[0025] In the depicted boot 10, the midsole is polyurethane. Polyurethane is generally well-known in the footwear industry, and therefore will not be described in detail. The rigidity and flexibility of the polyurethane can be varied from application to application, as desired, using a variety of well-known techniques, such as by adjusting the type and proportionate amount of the reactants that make up the material. In addition, the rigidity and flexibility of the polyurethane can be varied by adjusting the volume of polyurethane used. Although the polyurethane is the preferred midsole material, the density and precise chemical make-up of the midsole material may vary depending on a variety of factors, including the size of void defined between the protrusions 24 and the upper surface 32, or the recesses 28 and the desired cushioning and flexibility characteristics of the boot.

Manufacture and Assembly

[0026] The boot 10 is manufactured using direct attach machinery. In particular, the upper 50 is manufactured using generally conventional techniques and apparatus. The desired upper material (not shown) is cut to form the various elements of the upper, including the quarter 52, vamp 54 and backstay 56. The elements of the upper 50 are then fitted and sewn together. A lining (not shown) may be sewn within the upper during the fitting step. The fitted upper 50 is stretched over a last (not shown) and stapled to insole 60, preferably along the lower peripheral edge 58 of the upper 50 using conventional apparatus and techniques to intersecure the upper 50 and insole 60. Alternatively, insole 60 can be sewn or glued to the upper 50 in a conventional manner.

[0027] The outsole 20 is preferably injection or pour molded from a hard, durable rubber using conventional molding apparatus. The outsole 20 may be manufactured from other durable outsole materials. The protrusions 24, upper surface 32 and desired tread pattern in the outer surface 34 are all formed during the molding operation as an integral part of the outsole 20.

[0028] With the outsole 20 manufactured, it is direct attached to the midsole and upper as shown in FIG. 6. The machinery to perform the direct attachment preferably includes a die 80 that includes a top half 82 which receives the upper, and a bottom half 84 which receives the outsole 20. Optionally, the outsole 20 may include tabs 27 which are gripped by the die halves to better hold the outsole in place. The die halves are designed so they close to hold the upper in appropriate alignment with and a pre-selected distance above the outsole 20. The die halves upper and outsole also form the cavity 41 in which the midsole is formed.

[0029] With the outsole 20 and the upper inserted into the appropriate die halves, the appropriate volume of material to form the midsole 40 is injected through ports 86 into cavity 41. Preferably, the mold holds the upper 50 and outsole 20 firmly enough to prevent injected material from exiting the mold. As the material is injected into the void 41, it substantially surrounds, entraps, interlocks and direct attaches to the various components of the upper 50 and outsole 20. In particular, the material seeps into the void defined between the protrusions 24 and the upper surface 32, and substantially encapsulates the protrusions to form the mechanical interlock between the outsole and midsole in the finished boot. The material continues to be injected until enough is present in the cavity 41 to direct attach to both the upper 50 and the components of the outsole 20. Optionally, the material may be poured into the cavity above the outsole and the upper placed over the cavity immediately after pouring.

[0030] After the midsole material 40 is sufficiently cured to direct attach the midsole 40 to the upper 50 and outsole 20, the boot may be removed from the die 80.

[0031] A number of conventional finishing operations are performed on the boot 10. For example, the edges of the midsole 40 and outsole 20 are trimmed and shaped, with the tab 27 preferably being removed; the upper 50 is cleaned, polished, and treated as appropriate and necessary; and the laces are inserted in the eyelets.

[0032] The above descriptions are those of the preferred embodiments of the invention. Various alterations and changes can be made without departing from the spirit and broader aspects of the invention as defined in the appended claims, which are to be interpreted in accordance with the principles of patent law including the doctrine of equivalents. Any references to claim elements in the singular, for example, using the articles "a," "an," "the," or "said," is not to be construed as limiting the element to the singular.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An article of footwear comprising: an upper including a lower peripheral edge; an outsole including a wearing surface, an upper surface opposite the wearing surface, a peripheral wall extending upwardly around at least a portion of the upper surface, said peripheral wall including at least one protrusion extending inwardly from said peripheral wall and disposed above said upper surface a first pre-selected distance; and a material direct attached to said lower peripheral edge and said outsole so that said lower peripheral wall and the outsole are joined substantially only by direct attachment of the material to both the lower peripheral wall and the outsole.

2. The article of footwear of claim 1 wherein said outsole is disposed substantially entirely below said lower peripheral edge a second pre-selected distance.

3. The article of footwear of claim 1 wherein the peripheral wall includes a terminating end, said lower peripheral edge disposed a second pre-selected distance above the terminating end.

4. The article of footwear of claim 1 wherein the wearing surface includes a tread, and a portion of the tread is reflected in the upper surface.

5. The article of footwear of claim 1 wherein the upper surface is textured to increase the surface area thereof.

6. The article of footwear of claim 5 wherein at least a portion of the upper surface conforms to the tread so that at least one recess is formed in the upper surface and wherein the material substantially fills the at least one recess.

7. The article of footwear of claim 1 wherein the protrusions are circular sections and are substantially encapsulated by the material.

8. The article of footwear of claim 7 wherein the material is polyurethane.

9. A footwear construction comprising: an upper; a midsole direct attached to said upper, said midsole including a base and defining a peripheral groove; and an outsole including a wearing surface and an upper surface opposite said wearing surface, said outsole including a periphery bounded at least partially by a wall, said wall including a wall interior and at least one protrusion extending inwardly from said wall interior, said protrusion direct attached to said midsole within said peripheral groove to form a mechanical interlock between the outsole and said midsole, said outsole secured to the upper substantially only by direct attachment of the upper to the midsole and direct attachment of the midsole to the outsole.

10. The footwear construction of claim 9 wherein said wall exterior is viewable by a wearer.

11. The footwear construction of claim 9 wherein said at least one protrusion is a rib, and wherein the peripheral groove conforms to said rib and said midsole encapsulates said rib.

12. The footwear construction of claim 9 wherein said at least one protrusion extends substantially around the periphery.

13. The footwear construction of claim 12 wherein said at least one protrusion is of a circular section shape.

14. The footwear construction of claim 9 wherein the midsole includes a midsole exterior.

15. The footwear construction of claim 14 wherein the wall exterior and the midsole exterior are both viewable by a user.

16. The footwear construction of claim 14 wherein said midsole exterior co-terminates with said wall exterior.

17. A method for constructing an article of footwear comprising: providing an upper; providing an outsole including a bottom and a wall extending upwardly from the bottom and including an inwardly extending protrusion separated from the bottom a pre-selected distance to form a void; positioning the outsole and upper in a mold; introducing a material into the mold between the outsole and the upper so that the outsole and upper are secured together substantially only by the direct attachment of the material to both, wherein the material substantially fills the void and substantially encapsulates the protrusion.

18. The method of claim 17 wherein the bottom includes an upper surface and a tread, and wherein the tread is reflected in the upper surface to define a plurality of recesses.

19. The method of claim 18 wherein the material substantially fills the recesses in said introducing step.

20. The method of claim 19 wherein the encapsulation of the protrusion forms a mechanical interlock between the material and the outsole when the material cures.