Abstract: A mechanical drive assembly composed of an endless roller chain (78) and notched rail (100) wherein multiple chain rollers (79) engage corresponding rail notches (103 ) to securely interlock drive (38) and rail (100). Drive (38) is equipped with a triple-strand roller chain (78) whose center strand of rollers engage notched bar (102) while outer strand rollers roll across face of pressure plate (50). Drive assembly (38) may be held in a fixed position relative to a static rail (100) by applying a braking force to drive sprocket (76), or it may be moved tangentially to rail (100) by applying torque to drive sprocket (76). Conversely, rail (100) and any structure attached thereto may be held in a fixed position or moved tangentially relative to a statically mounted drive (38) by similar means.

Abstract: A hand exercising apparatus uses two flexible hollow handles connected together by a conduit. The user alternately squeezes one handle then the other. Liquid contained in the handles and conduit will flow from one handle to the other. Valves located in each handle will restrict or increase the flow area to change the resistance.