Derailleur for bicycle

Claim 1

A derailleur for a bicycle having a frame member, said derailleur comprising: a bracket fixed to the frame member of the bicycle, a support mounted to said bracket and rotatable relative thereto through a given range, two parallel links, one end of each of said links being pivotally connected to said support, a movable member pivotally connected to the other end of each of said links, a chain change-over frame having two chain-guide sprocket wheels, said frame being mounted to said movable member and rotatable relative thereto through a given range, said bracket having a base and a forked end, mounting means connected to the base for rotatably carrying said support thereon, said support and said movable member each comprising a front wall parallel to said bracket, a side wall extending toward said bracket adjacent to said front wall, and mounting walls opposite to each other and extending adjacent to said side wall, a first tubular member integral with and extending from a central portion of said front wall of the support said first tubular member being rotatably sleeved to said mounting means connected to the base of said bracket to thereby rotatably support said support, said chain change-over frame comprising two guide plates rotatably carrying two chain-guide sprocket wheels therewith, one of said two guide plates having mounting means for being rotatably supported on said movable member, and a second tubular member integral with said front wall of the movable member and extending from said front wall of the movable member toward said one of said guide plates, said second tubular member being rotatably sleeved to said mounting means of said one of said guide plates so that said guide plates may be rotatably supported on said movable member.