Camshaft for reciprocable piston engines

Claim 1

A camshaft for reciprocable piston engines, the camshaft comprising in combination: a tubular member having an outer peripheral surface and a wall of constant thickness, said tubular member being formed to rotate about a longitudinal axis and having a round portion with a wall equidistant from the axis; a plurality of longitudinally extending, uniform undulations formed by the wall of the tubular member, said undulations having an outer surface projecting beyond the round portion; and extending a limited distance in the longitudinal direction; a bearing friction fitted against the undulations and having an inner surface conforming to the outer surface of the undulations; longitudinally spaced cam positions on the tubular member, each cam position being formed by radially displacing a portion of the wall of the tubular member generally in one radial direction to form a first arcuate outer surface of the wall of the tubular member, displaced toward the axis of the tubular member, and a second arcuate portion of the wall of the tubular member displaced away from the axis to form a convex bulge curved in three dimensions wherein the cam position has an out-of-round configuration, and cam members frictionally secured to the tubular member at the cam positions, each cam member comprising a straight tubular section conforming to the shape of the tubular member around a substantial portion thereof and having a lobe coextensive with the bulge but radially displaced from the bulge to define a space between the inner surface of the lobe and outer surface of the bulge whereby the cam members are securely maintained by the out-of-round configuration of the cam positions.