The present invention relates to footwear, and more particularly to a sole assembly for an article of footwear.
A typical article of footwear includes an upper and a sole assembly. The general function of the upper is to receive the wearer's foot and secure it to the sole assembly. Uppers are available in a wide variety of shapes and style for forming a broad range of categories of footwear, such as casual shoes, dress shoes, athletic shoes, work boots, dress boots, outdoor boots, casual sandals, dress sandals and performance sandals. The sole assembly is affixed to the undersurface of the upper and its general function is to provide a layer of protection for the wearer's foot. The sole assembly can be designed not only to protect the foot from contact with the ground, but also to provide improved comfort and support for the foot.
There is an ongoing effort to develop new and improved sole constructions that provide optimal performance across various applications. To provide enhanced support, energy return and durability, it is not uncommon to incorporate a relatively rigid plate into a sole assembly. A typical plate is configured to resiliently bend during normal use to, among other things, store energy during heel strike and return it to the wearer during toe off. Conventional plate constructions can suffer from a number of typical problems. Because plates are relatively rigid, it can be difficult to develop a sole assembly with a plate that provides adequate support while remaining comfortable for day to day use. Although the stiffness of a plate can be reduced to improve flexibility, if the stiffness is reduced too much the support, energy return and durability functions of the plate can be defeated. As a result, incorporation of a plate into a sole assembly typically requires a balance between the competing objectives of comfort on the one hand and support, energy return and durability on the other hand.
Despite continuing efforts, there remains a need for a sole assembly that provides an appropriate balance between comfort, support, energy return and durability.