Adjustable bicycle crank assembly with preloaded bearings and cotterless cranks

Claim 1

A driving assembly for a bicycle comprising a bracket axle provided with screw rods positioned at opposite ends thereof, tapered portions having planar portions positioned inwardly of each said screw rod and threaded portions positioned inwardly of said tapered portions, said screw portions having grooves therein extending in the axial direction; washers mounted on the screw portions of said bracket axle, said washers having a projection thereon which engages the grooves in said bracket axle, thereby preventing the rotation of said washers relative to said bracket axle; nuts screwed onto the threaded portion of said bracket axle for holding said washers and race members in fixed positions thereon; ball retainers opposing said race members and cooperative therewith to retain balls betwen said ball retainers and said race members; an axle housing holding said ball retainers and rotatably supporting said bracket axle therein; right and left cranks each having at its head a tapered hole for receiving said tapered portion of said bracket axle and a recess communicating with the tapered hole, the tapered hole being defined by planar surfaces fittingly engageable with the planar surfaces of said tapered portion, wherein said tapered portions of said bracket axle are fitted in said tapered holes of the right and left cranks such that said axle and cranks are rotatable together and said screw rods of said bracket axle are positioned in said recesses in the cranks, said bracket axle and said right and left cranks being fastened together by nuts inserted into the recesses and screwed onto the screw rods; and at least one sprocket fixed to one of said cranks.