International Classification:
B62M 102
Abstract:
A drive unit of a bicycle includes a crankshaft having a pair of cranks, a chain wheel fixed to the crankshaft, and a free wheel fixed to a rotating shaft of a rear wheel and rotatably mounted on the crankshaft. An opposed pair of support frames rotatably support the crankshaft as well as the rear wheel and is hinged to a horizontal frame supporting a saddle such that the rear wheel support frames can be folded about the hinge to reduce the total length of the bicycle. A speed change unit includes a shaft rotatably supported by the pair of support frames on which a free wheel and a speed change wheel are mounted. A pair of chains connect the crankshaft and the free wheel of the drive unit to the speed change wheel and the free wheel of the speed change unit to transmit the rotating force of the chain wheel to the free wheel of the drive unit. The hinge locates the axis of the crankshaft of the drive unit on or behind a vertical center line of the saddle to reduce fatigue in operating the bicycle.
