Natural-cushioning, sock liner apparatus and method

Abstract

A sock liner (fitting above an insole of an article of footwear) includes a base layer between a thinner top layer, typically fabric contacting a sock in a shoe, and an intermediate layer below for shaping. The intermediate layer is a tailored series of projections, each extending from the medial side toward the lateral side. Together, these contain locally the individual regions of the 'fat pad,' extending along the underside of a foot, providing the natural cushioning of bones, muscles, tendons, and ligaments thereabove. The liner may provide flex, stiffness, lift, cushioning, or the like in areas of the heel, arch, metatarsals, and forefoot. The layup typically includes multiple layers of expanded polymer material (plastic or elastomeric foam). These may be cut, overlaid, embossed, debossed, or a combination, in or out of a mold, to locally alter density, thickness, softness, or stiffness.