Abstract: A drive mechanism for use in a man-driven vehicle having a front fork to which a wheel is rotatably connected includes a rack, a power drive and a quick-release lock. The rack is affixed to the front fork of the man-driven vehicle. The power drive has a transmission shaft pressable on a periphery of the wheel of the front fork, and a motor coupled to the transmission shaft for driving the transmission shaft to rotate. The quick-release lock is coupled between said power drive and said rack for locking said power drive and said rack together, thereby enabling the user to select the man power driving mode or motor driving mode.

Abstract: A drive mechanism for use in a man-driven vehicle having a front fork to which a wheel is rotatably connected includes a rack, a power drive and a quick-release lock. The rack is affixed to the front fork of the man-driven vehicle. The power drive has a transmission shaft pressable on a periphery of the wheel of the front fork, and a motor coupled to the transmission shaft for driving the transmission shaft to rotate. The quick-release lock is coupled between said power drive and said rack for locking said power drive and said rack together, thereby enabling the user to select the man power driving mode or motor driving mode.

Abstract: A bicycle folding stem with positioning structure comprises a frame having a seat tube and a head tube. A seat post has a tube inserted into the seat tube of the frame to be lifted and lowered and to be secured at any position. A seat is mounted on an end of the seat post having a locking portion. A front fork has a tube inserted into the head tube of the frame and a fork body at the bottom end of the tube for pivoting a wheel. A stem is pivoted on the front fork at the top end thereof to be turned to the seat post for said seat post being lowered and said locking portion of said seat locked said stem.