Patent ID: 8474564

Claim:
A wheel propulsion device for propelling a bicycle having a steering column with a steering axis, said steering column including a handlebar descending to a front fork, said fork having a pair of downwardly descending opposing legs, each leg having a lower dropout, said wheel propulsion device comprising: (a) a rotatable wheel; (b) a hub motor to rotate the wheel with respect to said steering column; (c) an axle with a flat radial surface to transfer torque from said hub motor, disposed such that said axle is inserted in each said lower dropout as said wheel propulsion device is installed on said bicycle; (d) a torque transfer bushing featuring a flat surface on its inner diameter, disposed such that said torque transfer bushing will rotationally engage said flat radial surface of said axle, thereby transferring torque from said axle to said steering column; (e) a threaded member surrounding said axle, disposed such that said torque transfer bushing is urged toward said dropout as said threaded member is rotated; (f) a yoke connected to said torque transfer bushing, disposed such that said yoke is urged away from said dropout as said threaded member is counter-rotated.