Patent ID: 6840136

Claim:
A pedal drive mechanism that provides full-time, continuous torque to a drive chain or belt, comprising: a) a bottom bracket hub collar adapted to mount to a bottom bracket housing; b) a left pedal output crank having a rotational output end and an opposing end, the left pedal output crank being rotatably mounted at the opposing end to said bottom bracket hub collar, such that the left pedal output crank is rotatable about a first axis of rotation, c) an eccentric flange and a bearing inner race support on said bottom bracket hub collar, the eccentric flange and bearing inner race support establishing a second axis of rotation parallel to and offset from said first axis of rotation; d) a right pedal crank mounted to the bottom bracket hub collar so as to be rotatable about said first axis of rotation separately from the rotation of the left pedal output crank about the first axis of rotation; e) a sprocket support mounted on said bearing inner race support such that said sprocket support is rotatable about said second axis of rotation; and f) a first articulating link connectively joining said sprocket support with the rotational output end of the left pedal output crank, and a second articulating link joining said sprocket support with the right pedal crank, wherein said first and second articulating links are joined to said left pedal output crank and right pedal crank, respectively, on the same radial arc about the first axis of rotation; g) the pedal drive mechanism being adapted to attach externally to a bottom bracket housing and to attach to a bottom bracket bearing disposed within said bottom bracket housing such that the bottom bracket bearing is rotatable together with said left pedal output crank about said first axis of rotation.