US Patent 9845134 Bicycle rear derailleur with a motion resisting structure

A bicycle derailleur comprises a base member adapted to be mounted to a bicycle, a movable member movably coupled to the base member, and a chain guide coupled to the movable member. The chain guide is coupled for rotation around a rotational axis (X), and a biasing element biases the chain guide in a selected rotational direction. A resistance applying unit applies a resistance to rotational movement of the chain guide in a direction opposite the selected rotational direction, and an adjusting unit adjusts an amount of resistance applied by the resistance applying unit.