Patent ID: 7762916
Filing Date: 2010-07-27
Classification: B62M

Abstract:
1. A front derailleur for a bicycle adapted to be installed on a frame of the bicycle for guiding a chain into one of a plurality of shift positions in accordance with movement of a transmission member, the front derailleur comprising: a base member configured and arranged to be installed on the frame; a chain guide freely movable with respect to the base member in a shifting direction away from the base member to guide the chain into one of the shift positions; an inner link being freely rotatably connected to the base member at a first pivot connection and to the chain guide at a second pivot connection; an outer link disposed substantially parallel to the inner link in a position spaced apart from the base member with respect to the inner link with the outer link being freely rotatably connected to the base member at a first pivot connection and to the chain guide at a second pivot connection; a first arm portion fixed to one of the inner link and the outer link and extending outwardly from the one of the inner link and the outer link having the first arm portion in a direction away from the base member; and a coil spring with a first end attached to the base member and a second end attached to a free end of the first arm portion at a fixed attachment point that is spaced from the first and second pivot connections of the one of the inner and outer links having the first arm portion, the coil spring applying a biasing force on the chain guide in a direction toward the frame when the base member is installed on the frame, the first arm portion being arranged with the fixed attachment point disposed such that a center axis of the coil spring approaches a center of rotation of the first pivot connection of the one of the inner and outer links having the first arm portion as the chain guide moves from a position closest to the base member toward a position that is farthest apart from the base member.