Pedal crank and chain wheel assembly for bicycles

A pedal crank and chainwheel combination for a bicycle, comprising a pedal crank having a crankshaft end, a chain wheel coacting with and inwardly adjacent the pedal crank, a lost motion coupling including means supporting the chain wheel on the crankshaft end for relative motion about the axis of the crankshaft, and torque responsive means acting between the pedal crank and the chain wheel to take up the lost motion of the lost motion coupling, the means supporting the chainwheel comprising an annular chain wheel carrier concentric with the chain wheel, a shoulder formed at the crankshaft end of the pedal crank and restraining the chain wheel carrier against radial or axially outward movement, the chain wheel carrier having a hub with an external cylindrical bearing surface engaging an internal periphery of the chain wheel, and a flange with an annular surface engaging an outer surface of the chain wheel in an annular zone, a resilient annular washer on its outward facing surface, an inner annular support surface engaging the carrier hub and an outer annular support surface engaging an inner surface of the chain wheel in an annular zone spaced outwardly of said internal pheriphery, an external screw thread formed on said crankshaft end concentric with the chain wheel and inward of the shoulder, and a nut engaged with the screw thread and having an annular land engaging an inner surface of the annular washer radially outward of its inner annular bearing surface to deform the washer into a frustum of a cone, whereby to take up play between the chain wheel, the outer annular support surface of the washer and the annular support surface of the carrier, and prevent relative motion of the chainwheel and the crankshaft other than about the axis of the latter.