| abstract |
A biochemically tuned shoe has a heel construction that provides a force-deflection response which is optimal for a particular person and a particular use. The heel construction features a main spring that is characterized by a large vertical compliance while at the same time exhibiting an extremely high resistance to a lateral shear (horizontal compliance). The main spring is preferably a coned disk spring formed of a plastic material or a vertical stack of operatively coupled coned disk springs. The main spring can be embedded in a conventionally shaped heel formed of a resilient material such as an open or closed cell foamed rubber or plastic secured to the sole of the shoe. In other forms, the heel construction is replaceably secured to the sole by a threaded stud with or without an intermediate assembly. In a preferred form, the main spring acts in cooperation with a resilient member to extend the characteristic load deflection curve of the main spring. The resilient member can be the foamed rubber or plastic heel material that embeds the main spring or a column of a highly resilient material such as a soft rubber located at the center of the coned disk main spring. The heel construction of this invention provides a vertical compliance, expressed as its inverse, a spring constant, of 3,000 to 25,000 lbf/ft. In terms of deflection, when used in an adult running shoe, the heel exhibits a maximum deflection of 1/8 inch to 5/8 inch at the peak applied load, typically 400 to 500 pounds of force (lbf). |