US Patent 7438657 Bicycle front derailleur

A bicycle front derailleur includes a fixing member, a chain guide and a linkage mechanism. The fixing member includes axially aligned first and second attachment flanges. The linkage mechanism couples the chain guide to the fixing member for movement between a retracted position and an extended position. The linkage mechanism includes a first link, a second link, a first pivot pin and a second pivot pin. The second link is rotatably coupled to the first and second attachment flanges. The first pivot pin rotatably couples the second link to the first attachment flange, and the second pivot pin rotatably couples the second link to the second attachment flange. One of the first and second pivot pins is retained in place at both ends, and the other is retained at one end only.