Patent ID: 7181823

Claim:
A method for manufacturing a crank arm and spider assembly comprising the following steps: (1) providing a blank; (2) shaping the blank to form a crank billet comprising an elongate body having a first end on which a spider is integrally formed and an opposite end having an expanded outside diameter; (3) forming a channel substantially co-extensive with the elongate body with an opening an the opposite end of the body; (4) reducing the expanded second end and thereby reducing inside diameter of the channel in proximity of the opposite end for forming an entry of the channel; (5) filing a liquid into the channel through the entry and then sealing the entry: (6) placing the crank billet with the liquid filled in the channel into a mold and performing a mold forging operation to obtain a semi-product; and (7) forming a hole in the body to release the filling liquid out of the channel of the crank.