Footwear with a hybrid outsole structure

Abstract

A hybrid outsole construction comprises high-density carbon rubber molded to low-density blown rubber, providing increased flexibility, cushion, and comfort while maintaining durability, traction, and shock absorbency of the footwear. In accordance with another aspect of the present invention, the hybrid outsole construction is stitched to the upper layers of the footwear, for example using a welt.

Description

[0001] This application claims the priority of U.S. Provisional Patent Application No. 60/327,139, filed Oct. 3, 2001.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention relates to footwear, particularly to footwear to be used in a rugged environment, of lighter weight, additional comfort, and durability.

[0004] 2. Description of Related Art

[0005] A principal goal in shoe design is to design footwear that is sturdy enough to protect the wearer's feet, yet flexible enough to provide for comfortable walking. This is particularly true for rugged footwear such as work boots or hiking boots, where comfort is often compromised in a design for well-built footwear that can withstand harsh conditions.

[0006] The outsole of rugged footwear is designed to resist wear, provide durability, traction and absorb shock. Commonly, the outsole material is made of high-density carbon rubber, which is a relatively heavy and durable but stiff material. High-density carbon rubber provides very little in the area of flexibility and cushion. Thus, the construction of an outsole of a rugged footwear must take into account the weight, flexibility and durability of materials used in providing the necessary comfort and strength to the footwear.

SUMMARY OF THE INVENTION

[0007] The present invention is directed to a hybrid outsole construction comprised of high-density carbon rubber and low-density blown rubber, providing increased flexibility, cushion, and comfort while maintaining durability, traction, and shock absorbency of the footwear. Unlike prior art outsole construction, the present invention makes use of a hybrid structure to manufacture the outsole. High-density carbon rubber molded to low-density blown rubber comprises the hybrid outsole construction.

[0008] One aspect of the invention contains low-density blown rubber for added cushioning throughout the outsole as well as high-density carbon rubber for durability, especially in high-wear areas like the heel. A material for the low-density blown rubber should be flexible, such as EMAX. EMAX provides the desired flexibility, increased cushion, and lighter weight. Ethylene-vinyl acetate (EVA) can also be used instead of the blown rubber. Other low density, resilient synthetic plastic foam materials may be used, such as polyurethane, polyethylene and polyethylene vinyl acetate.

[0009] The use of low-density blown rubber, made by injecting air into a rubber compound, is well known in prior art associated with fitness-related footwear. No prior art, however, suggests the use of low-density blown rubber for providing increased agility and padding in rugged footwear like work boots.

[0010] Low-density blown rubber, however, is less durable against wear than high-density carbon rubber. High-density carbon rubber molded around the EMAX, exhibits good wear resistance characteristics and preserves the strength and efficacy of the footwear. In accordance with another aspect of the present invention, the hybrid outsole construction is stitched to the upper layers of the footwear, for example using a welt.

[0011] In another aspect of the present invention, the hybrid outsole construction includes providing the high-density carbon rubber layer with holes to expose the underlying low-density blown rubber. Portions of the exposed low-density blown rubber can extend through the holes to be formed into structures such as treads.

BRIEF DESCRIPTIONS OF THE DRAWINGS

[0012] The present invention will be more clearly understood when considered in conjunction with the accompanying drawings. In the following drawings, like reference numerals designate like or similar parts throughout the drawings.

[0013] FIG. 1 is a right side view of a footwear incorporating a hybrid outsole construction in accordance with one embodiment of the present invention.

[0014] FIG. 2 is a cross sectional view of the footwear shown in FIG. 1, taken along line 2-2.

[0015] FIG. 3 is a bottom view of the footwear shown in FIG. 1.

[0016] FIG. 4 is a side view of one embodiment of a three-quarter-welt cup heel footwear showing the various components of the footwear including the hybrid outsole construction with exposed low-density blown rubber arch.

[0017] FIG. 5 is a rear heel-sectional view taken along line 5-5 in FIG. 4.

[0018] FIG. 6 is a front toe-sectional view taken along line 6-6 in FIG. 4.

[0019] FIG. 7 is a side view of another embodiment of a lightweight welted footwear showing the various components of the footwear including the hybrid outsole construction, with high-density carbon rubber undersurface.

[0020] FIG. 8 is a rear heel-sectional view taken along line 8-8 in FIG. 7.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0021] The present description is the best contemplated mode of carrying out the invention. This description is made for the purpose of illustrating general principles of the invention and should not be taken in a limiting sense.

[0022] FIG. 1 illustrates a right side view of a footwear or shoe 70 incorporating a hybrid outsole construction 75 in accordance with one embodiment of the present invention. The footwear 70 comprises an upper portion 80 and the hybrid outsole construction or the lower outsole portion 75. The upper portion 80 is shaped to receive the right foot of a wearer and to secure the right foot of the wearer within the upper portion 80. The lower outsole portion 75 is coupled to the upper portion 80, and is adapted to support the weight of the wearer on top, and is capable of traction against rough outside contact surfaces on bottom. The lower outsole portion 75 comprises an outer sole layer 85 and an inner sole layer 90. The outer sole layer 85 is formed from a substantially wear resistant material, such as high-density carbon rubber. The inner sole layer 90 is disposed between the upper portion 80 and the outer sole layer 85. The inner sole layer 90 is formed from a substantially resilient cushioning material that is substantially softer than the wear resistant material forming the outer sole layer 85. The resilient material can be low-density blown rubber, such as EMAX, EVA, polyurethane, polyethylene or polyethylene vinyl acetate. The lower outsole portion 75 can also comprise an upper sole layer 95 disposed between the upper portion 80 and the inner sole layer 90. The upper sole layer 95 can be formed from the same wear resistant material, such as high-density rubber. The inner sole layer 90 is therefore sandwiched between the upper sole layer 95 and the outer sole layer 85.

[0023] The outer sole layer 85, the inner sole layer 90, and the upper sole layer 95 are coextensive along their lengths and widths. As shown in FIG. 1, the inner sole layer 90 is exposed along its perimeter sides. In some embodiments of the present invention, the exposed sides of the inner sole layer 90 allow the inner sole layer 90 to deform or expand laterally as the wearer applies vertical pressure to the lower outsole portion 75. The amount of deformation will depend on the resilience of the inner sole layer material 90. In some embodiments of the present invention, the inner sole layer 90 will not substantially deform under application of vertical pressure.

[0024] In the embodiment shown in FIG. 1, the inner sole layer 90 has a variable thickness along its length. The inner sole layer 90 is thicker at a heel section 100 of the lower outsole portion 75 than at a toe section 105 of the lower outsole portion 75. Since vertical pressure can be greatest at the heel section 100, the additional thickness at the heel section 100 allows for additional cushion at the heel section 100 to provide additional wearer comfort. In some embodiments of the present invention (not shown), the thickness of the inner sole layer 90 is uniform along its length.

[0025] The lower outsole portion 75 may be assembled to the upper portion 80 using a welt construction, such as the American Goodyear welt 110. The American Goodyear welt 110 is used for heavy-duty shoe construction, such as a work boot or hiking boot. The welt construction utilizes treated cotton twine to stitch the welt 110 to the upper portion 80 and to the lower outsole portion 75. As shown in FIG. 1, the welt 110 can run around the entire perimeter of the upper portion 80 and the lower outsole portion 75. Alternatively, the welt can run around the front perimeter of the toe area and approximately three-quarters the inner and outer length of the footwear ending at the cup heel (not shown).

[0026] FIG. 2 is a cross sectional view of the footwear 70 shown in FIG. 1, taken through line 2-2. The outer sole layer 85 comprises one or more holes 115 defined through the layer 85. The holes 115 expose the underlying inner sole layer 90, allowing portions of the inner sole layer 90 to extend and be formed through the holes 115. For example, portion 92 of the inner sole layer 85 can be formed into a tread.

[0027] FIG. 3 illustrates a bottom view of the footwear 70 shown in FIG. 1. The outer sole layer 85 includes a plurality of treads 87 for contact with the ground. The treads 87 can have any shape and pattern that allows for optimum traction with the ground. FIG. 3 also illustrates a plurality of treads 92 formed from portions of the inner sole layer 90 exposed through the holes 115 in the outer sole layer 85. Treads 92 and 87 form a contact surface with the ground. As treads 92 contact with the ground, the more resilient treads 92 can provide additional impact absorption, while the more wear resistant treads 87 can provide sufficient traction with the ground.

[0028] FIG. 4 illustrates a side view of one embodiment of the present invention by way of illustration only and not by limitation, a three-quarter-welt cup heel footwear 10 incorporating a hybrid outsole construction 14. It is noted that the illustration shows the right side of the footwear. The three-quarter-welt cup heel footwear 10 is made of an upper 12 that is created to conform to the shape of the right foot of the wearer, and the hybrid outsole 14 for support of the weight of the wearer on top and for traction against rough outside contact surfaces on bottom. The hybrid outsole 14 is comprised of layers of different materials: a wear resistant layer of high-density carbon rubber (outer sole layer) 16 trimmed at the edges, and a relatively soft, cushion layer of low-density blown rubber (inner sole layer) 18, such as EMAX, untrimmed and set back from the outsole sidewall, which is made of the high-density carbon rubber 16. Other low density, resilient synthetic plastic foam materials may be used in place of EMAX, such as EVA, polyurethane, polyethylene and polyethylene vinyl acetate.

[0029] The hybrid outsole construction 14 is achieved by molding the high-density carbon rubber 16 around certain areas of previously created low-density blown rubber 18. High-density carbon rubber 16 bounds the low-density blown rubber 18 on all sides (e.g., underneath the upper 12, at the toe and heel areas, and the bottom), but not on the lateral sides and the underside of an arch area 28. Without high-density carbon rubber underneath the arch 28, the footwear 10 can be more flexible to the wearer's movement.

[0030] In some embodiments of the present invention, because the low-density blown rubber 18 is not bound on all sides and because it is set back or recessed from the outsole sidewall, space is provided to allow the low-density blown rubber 18 to substantially deform or expand laterally as vertical pressure (i.e., under the weight of the wearer) is applied to the hybrid outsole 14. Further, the low-density blown rubber 18 in the arch area 28 substantially deforms into the space beneath the arch area 28 when vertical pressure is applied to the hybrid outsole 14. When the pressure is removed, the low-density blown rubber 18 recovers its shape and once again is recessed from the outsole sidewall. In some embodiments of the present invention (not shown), the low-density blown rubber 18 does not substantially deform under the vertical pressure.

[0031] The hybrid outsole 14 may be assembled to the upper 12 using a welt construction, such as the American Goodyear welt 20, which utilizes stitching 22, with treated cotton twine, the welt to the upper 12 and the outsole 14 (e.g., for a heavy duty shoe construction, such as a work boot or hiking boot). The welt 20 runs around the front perimeter of the toe area and approximately three-quarters the inner and outer length of the footwear 10 ending at the cup heel 24.

[0032] FIG. 5 illustrates a rear heel-sectional view of FIG. 4 displaying the hybrid outsole 14 and its components: the high-density carbon rubber 16, which is trimmed at the edges of the footwear; and the low-density blown rubber 18, which is untrimmed and recessed from the high-density carbon rubber 16 sidewall. FIG. 5 shows the state in which the low-density blown rubber 18 expands laterally to a convex profile, acting as a cushion when vertical weight is applied. When the weight is removed, the low-density blown rubber 18 contracts back to its original position, with the lateral edge of the rubber 18 in a concave profile (see dotted line 17). The cup heel 24 and the high-density carbon rubber 16 of the hybrid outsole 14 are one continuous piece of rubber. The cup heel 24 may be cement lasted and stitched.

[0033] FIG. 6 illustrates a front toe-sectional view of FIG. 4 showing the hybrid outsole 14 consisting of high-density carbon rubber 16 and low-density blown rubber 18. As shown in FIG. 6, when vertical pressure is applied to the hybrid outsole 14, the low-density blown rubber 18 expands laterally here as well, forming a convex profile. When vertical pressure is released, the sidewall of the rubber 18 contracts to a concave profile 17.

[0034] FIG. 7 illustrates a side view of another embodiment of a hybrid outsole 54, a lightweight welted footwear 50. The hybrid outsole 54 is comprised of trimmed high-density carbon rubber (outer sole layer) 56 and untrimmed, recessed, low-density blown rubber (inner sole layer) 58, such as EMAX. The high-density carbon rubber 56 covers the low-density blown rubber 58 in certain areas: at the top, bottom, front and back, but not on the sides. The low-density blown rubber 58 is able to substantially deform and expand laterally as pressure is applied vertically to the hybrid outsole 54. When the pressure is removed, the low-density blown rubber 58 will contract to its original state. Alternatively, the low-density rubber 58 does not substantially deform under the applied pressure.

[0035] The hybrid outsole 54 is assembled to the upper 52 with a welt 60 and treated cotton twine stitching 62. The stitching 62 extends through the hybrid outsole 54, the welt 60, and the upper 52. The welt 60 runs completely around the lightweight welted footwear 50.

[0036] FIG. 8 illustrates a rear heel-sectional view of FIG. 7 displaying the trimmed high-density carbon rubber 56 and the untrimmed, recessed, low-density blown rubber 58 comprising the hybrid outsole 54. When vertical pressure is applied to the hybrid outsole, the low-density blown rubber 58 expands laterally until the pressure is removed, retracting back to a convex profile 17.

[0037] While the invention has been described in detail with respect to the illustrated embodiments in accordance therewith, it will be apparent to those skilled in the art that various changes, modifications, substitutions, alterations and improvement may be made without departing from the scope and spirit of the invention as defined by the appended claims.

Claims

1. A shoe including an upper portion and an outsole portion coupled to the upper portion, the outsole portion comprising:

an outer sole layer formed from a substantially wear resistant material for traction on a walking surface, wherein the outer sole layer includes a shaped hole defined through the outer sole layer; and

an inner sole layer formed from a substantially resilient cushioning material, wherein the inner sole layer is disposed between the outer sole layer and the upper portion, wherein a portion of the inner sole layer extends through the shaped hole in the outer sole layer.

2. The shoe of claim 1, wherein the outer sole layer includes a plurality of treads, and wherein the portion of the inner sole layer extending through the shaped hole defines a tread.

3. The shoe of claim 2, wherein the inner sole layer comprises a heel section and a toe section, wherein the heel section is substantially thicker than the toe section.

4. The shoe of claim 1, wherein the upper portion and the outsole portion are coupled by stitching a welt to the upper portion and the outsole portion.

5. The shoe of claim 3, wherein the sides of the inner sole layer are exposed, so to allow the inner sole layer to deform out through the sides of the outer sole layer under the weight of a wearer.

6. The shoe of claim 5, further comprising an upper sole layer disposed between the upper portion and the inner sole layer.

7. The shoe of claim 6, wherein the wear resistant material comprises carbon rubber, and the resilient material comprises blown rubber.

8. A footwear comprising:

an upper portion; and

a lower portion coupled to the upper portion, said lower portion having a toe section and a heel section, and comprising an outsole portion having a hybrid structure that includes an outer layer for traction on a walking surface and made of a wear resistant material, and an inner layer for cushioning made of a resilient material softer than the wear resistant material, wherein the outer layer covers entirely the front of the toe section and rear of the heel section of the inner layer, but exposing lateral sides of the inner layer.

9. The footwear as in claim 8, wherein the lower portion defines an arch area, at which the outer layer exposes the inner layer.

10. The footwear as in claim 8, wherein the exposed lateral sides of the inner layer has a convex profile in the absence of the weight of a user, and a concave profile under the weight of the user.

11. The footwear as in claim 8, wherein the upper portion and the lower potion are coupled by stitching.

12. The footwear as in claim 11, wherein the upper portion and the lower portion are coupled by stitching a welt to the upper portion and lower portion.

13. The footwear as in claim 8, wherein the exposed lateral side of the inner layer is recessed from an edge of the outer layer.

14. The footwear as in claim 8, wherein the resilient material comprises blown rubber, and the wear resistant material comprises carbon rubber.

15. A footwear comprising:

an upper portion; and

a lower portion coupled to the upper portion, and comprising an outsole portion having a hybrid structure that includes an outer layer for traction on a walking surface and made of a wear resistant material, and an inner layer for cushioning made of a resilient material softer than the wear resistant material;

wherein the upper portion is coupled to the lower portion by stitching a welt to the upper portion and the lower portion.

16. The footwear as in claim 15, wherein the inner layer includes an exposed lateral side recessed from an edge of the outer layer.

17. The footwear as in claim 15, wherein the exposed lateral side of the inner layer has a convex profile in the absence of the weight of a user, and a concave profile under the weight of the user.

18. The footwear as in claim 15, wherein the resilient material comprises blown rubber, and the wear resistant material comprises carbon rubber.

19. The footwear as in claim 15, wherein the lower portion defines an arch area, at which the outer layer exposes the inner layer.