The Hillclimber Bicycle Mfgr Company also had exclusive rights to use the patented one piece crank assembly issued to Conrad J. Dorff. The entire assembly- bearings, gear, and crank– was slipped into position on the bicycle frame and held in place by a locking ring (shown at #44) that prevented lateral movement. It could be easily removed for servicing by undoing the bolt (shown at #10), unsrcrewing the locking ring, and slipping out through a slot provided at the bottom of the crank housing on the frame. Click on drawings below to show the surviving part.