Recent Developments in Electric Propulsion under NASA's In-Space Propulsion Technology Project

A bicycle with a torsional shock absorber comprised of a torsion spring assembly. The elements of the torsion spring assembly include: housing, a shaft positioned within the housing, a rubbery substance positioned between the interior surface of the housing and the outer surface of the shaft. The torsional shock absorber is mounted on the bicycle such that shock forces are converted into rotational forces tending to rotate the shaft within the housing. These rotational forces are resisted by the spring force created by the rubbery substance within the torsion spring assembly; thereby absorbing the shock forces. In a preferred embodiment, the rubbery substance is bonded to the interior surface of the housing and the outer surface of the shaft. In a preferred embodiment, the front and rear portions of the bicycle frame pivot about the pedal spindle axis. Also, in a preferred embodiment, the housing of the torsion spring assembly is rigidly connected to the front portion of the bicycle frame in-between the top tube and middle brace and just in front of the seat tube. The rear portion of the bicycle frame is pivotally connected to two torsion arms rigidly connected to the shaft.