Abstract: A bicycle frame assembly including a shock absorbing system associated with a rear wheel. The frame assembly comprises a main frame section, chain stays, seat stays and a rocker arm element, which are combined with each other to form a four-link mechanism that is movable within a vertical plane including the main frame section. A shock absorbing device is arranged between the rocker arm element and the main frame body, for absorbing shocks transmitted from the rear wheel to the main frame section when the frame assembly is in use.

Abstract: A friction-type stepless speed change device includes a frictional transmission elements composed of a pair of driving discs connected to an input shaft, and an annular driven disc connected to an output shaft and embraced between and urged against opposite conical surfaces of the driving discs into wedge-engagement to generate frictional force and allow power transmission from the driving discs to the driven disc. The driving discs are at a variable eccentricity relative to the driven disc, with which an effective pitch diameter of the driving discs is varied to effect a stepless speed change. For reducing the size of the frictional transmission elements while preserving a required torque capacity, the device further comprises a driving rotary unit for transmitting power from the input shaft to the driving discs at an increased rotational speed, and a driven rotary unit for transmitting power from the driven disc to the output shaft at a reduced rotational speed.

Abstract: A foldable bicycle frame includes a substantially vertical center tube at a mid portion of a bicycle frame, an upper center tube and a lower center tube to be partially fitted in upper and lower ends of the center tube, respectively. A front half of the bicycle frame includes the center tube and a rear half of the bicycle frame include the upper and lower center tubes, thereby enabling the front and rear halves to be folded or extended about the vertical center tube into a folded position or running position. The bicycle frame comprises radially annularly arranged continuous V-shaped teeth on connection surfaces of the upper and lower center tubes and the center tubes, and clamping means for clamping the center tube and the upper and lower center tubes in engagement with the teeth on the connection surfaces, thereby enabling the bicycle frame to be folded or extended by releasing and then clamping the center tubes.