Abstract: Shock absorbing structures suitable for footware and the like may utilize a flexible polyurethane of essentially linear structure containing unsatisfied hydroxyl groups and having a compression set of less than 15%, an elongation break of at least 500%, and a recovery which is delayed after compression by at least 0.7 seconds. The structures include a block or layer with one or more fluid cavities, each cavity having one or more relatively small passageways communicating the cavity with the exterior of the block or layer. The cavities may be closed by a separate layer bonded to the block or layer. In footware, the cavities may be strategically located and circular or rectangular in form with the passageways being similarly shaped and extending through the top of the layer or block.

Abstract: A self energizing pipe gasket includes a base and arm configuration projecting therefrom which cooperates with the base when pipe sections are assembled to cause the lip or sealing edge of the arm to kick away or distend toward the sealing surface of the pipe. To facilitate this action a harder insert is provided in the base in the form of a reinforcing ring providing a less compressible surface for the arm to react against. The ring also stiffens the gasket making it more difficult to dislodge upon assembly of the pipe sections enabling higher compression forces and assuring that the gasket does not go under or below the minimal compression requirements to form a sound flexible yet fluid tight seal.