US Patent 11059542 Bicycle derailleur

A bicycle derailleur includes a lower link member including a position-limiting structure, an external chain-guiding member, a damping shaft, a connection member and a C-shape spring. The external chain-guiding member, connected pivotally with the lower link member, controls a tension of a chain. The connection member is connected with the lower link member. The damping shaft, mounted at one side of the lower link member, is connected pivotally with the external chain-guiding member. The C-shape spring, sleeving the damping shaft, includes a C-clip portion and a first plate portion disposed between the connection member and the position-limiting structure. The first plate portion is extended outward from one end of the C-clip portion in a direction leaving the damping shaft. A friction force upon the external chain-guiding member in the direction to relax the chain is greater than that in the direction to relax the chain.