Pressure relief system for footwear

Abstract

A shoe having a last which includes a shape and volume that reflects the thickness of an internal sock liner, and a shoe interior made specifically for inclusion of the sock liner. The sock liner itself includes an anatomically shaped foot bed surface with a cupped heel, contoured arch, radiused forepart and beveled toe area. The sock liner material specifications and thicknesses are engineered or tuned to have a high amount of deflection when compressed without getting stiff.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]The present application claims priority to and incorporates herein by reference U.S. Provisional Patent Application Ser. No. 61 / 491,190 filed on May 28, 2011.BACKGROUND OF INVENTION[0002]The present invention relates to a pressure relief system for footwear that relieves plantar pressures via an anatomical sock liner which is engineered with a shape designed to achieve a high amount of deflection when compressed without becoming stiff.[0003]Many footwear brands market shoes as “comfortable,” and there are many footwear products in the marketplace which claim to deliver on comfort. However, there is a misconception in the footwear industry as to what the definition of comfort actually is. Indeed, there is no universal standard for “comfort.” Consumers have a hard time understanding precisely what comfort means, and how it is designed into the footwear they are buying.[0004]Most articles of footwear are designed for the masses to wear. Howev...

AI Technical Summary

Benefits of technology

[0012]The sock liner of the present invention includes a raised area in the midfoot region and a recessed area located in the hind foot or heel region. The raised area is positioned to underlie the medial arch of the wearer's foot and the recessed area is positioned to underlie the heel of the wearer's foot. The recessed area is defined by the peripheral edges formed around the hind foot region from the medial side to the lateral side of the heel. The peripheral edge in the hind foot region forms a raised portion where it wraps around the heel of the wearer's foot. The anatomically shaped and formed sock liner reflects the natural shapes of the human foot. The shaped plantar surface topography maximizes surface contact with the wearer's foot and increases comfort.

[0016]The overall design of a sock liner according to the present invention should increase contact between the foot and sock liner surface—especially during weight bearing—preferably at or above 75% rate of surface contact between the foot and sock liner. The sock liner also improves pressure re-distribution from peak pressure areas, and spreads the pressure across the entire plantar surface area such that preferably no single location experiences a pressure above 40 psi. In so doing, cushioning and shock absorption protection should prevent stresses above 10 Gs.

[0017]In order to reduce such pressures exerted by the shoe against the plantar surface of the foot, the sock liner surface yields and deflects under the foot without a significant increase of hardness and stiffness of the sock liner, which could create discomfort. Such deflection can also increase foot stimulation through more utilization of bones, tendons, muscles during foot-strike. The deflection can also promote a wearer's natural gait / foot-strike during walking, by straightening the wearer's center of force trajectory during foot-strike. Further, a flexibility improvement may be realized where less foot force is required to bend a shoe across the foot's flex area. Preferably below about 5 pounds of force is required to bend flex the shoe at such flex areas.

Problems solved by technology

However, there is a misconception in the footwear industry as to what the definition of comfort actually is.

Indeed, there is no universal standard for “comfort.” Consumers have a hard time understanding precisely what comfort means, and how it is designed into the footwear they are buying.

However, the resulting fit and comfort experience will be different for everyone wearing a single shoe design, and satisfying such a broad range in population is very difficult.

Most non-athletic shoes today contain hard materials, flatter interior foot contact surfaces and / or are made with low density foams that easily bottom out (i.e., which fully compress too quickly, and therefore fail to provide sufficient cushioning).

These constructions lead to higher than desired interior pressures created against the plantar surface of the foot, which eventually lead to discomfort.

Essentially, most non-athletic shoes are build to be too hard and stiff.

However, these designs are not as comfortable when used for everyday wear, because the cushioning materials are tuned for the high-impact performance conditions, rather than the lower impact casual situations.

However, many of today's after-market insoles marketed for improving comfort or relieving foot problems cause fit and comfort compromises because these insoles were not designed holistically together with the shoes they are to be put inside.

The comfort potential of these insoles is often offset by the functional deficits of the footwear into which they are installed (hard, stiff, inflexible, heavy, etc.).

In most cases, layers of foam or other similar materials are added to the sole construction to create the initial perception of comfort, but such constructions typically lose their effect after a short time.

Many actually end up creating discomfort.

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