Abstract: A bicycle hub assembly includes a hub shell including a braking surface. A coaster brake shoe is accommodated in the hub shell and cooperates with the braking surface to generate braking force. A motor is accommodated in the hub shell and configured to be controlled for at least changing or maintaining a gear ratio.

Abstract: A clutch assembly comprises a cylindrical driving member, a cylindrical driven member, coaxial with the cylindrical driving member, and a clutch cylinder between the driving member and the driven member and coaxial with the driving member and the driven member. The clutch assembly further includes a spring biasing the clutch cylinder towards the clutch cylinder. The clutch assembly also includes a plurality of friction pads, each one being attached to a different one of movable portions, and acting in response to movement of its movable portion, to cause frictional engagement between the driving member and the driven member, so that the driving member rotates the driven member. The clutch assembly also includes a U-shaped spring located in a slot in the driving member and compressible between the driving member and the clutch cylinder for rotationally biasing the clutch cylinder relative to the driving member in a clutch engagement direction.

Abstract: A drive system for a velocipede, such as a tricycle, which includes forward and reverse pedaling capabilities as well as coasting and braking capabilities.

Abstract: An engaging and disengaging gear for a bicycle includes an axle rotatably mounted in a five-way tube on the bicycle to connect to two pedal cranks, a thimble fixedly connected to one end of the five-way tube, an internally threaded transmission bevel gear received in the thimble, a chain wheel mounted on the axle between the thimble and a collar of the axle, and a ring spring fixed to outer surface of the transmission gear. The axle has an externally threaded section between the thimble and the chain wheel for extending through and engaging with the internally threaded transmission gear. An outer periphery of the ring spring slightly contacts with inner wall of the thimble to provide a resistance to a maximum static friction force between the transmission gear and the axle that are screwed together. When the axle is caused to turn forward, the transmission gear moves along the axle toward the chain wheel and engages with the latter, causing the chain wheel to rotate forward, too.