Patent ID: 6840155

Claim:
A forged piston comprising: a piston head having a combustion bowl and a ring belt with a plurality of ring grooves formed therein; a pair of pin bosses extending downwardly from said piston head having pin bores formed therein aligned along a common pin bore axis transverse to a longitudinal axis of the piston head; a piston skirt forged as one piece with said pin bosses including a pair of opposed skirt portions spaced from said pin bosses and intervening strut portions extending between and uniting said skirt portions to said pin bosses, said strut portions presenting outer surfaces facing in opposite directions along said pin bore axis and having lower edges; and forged recesses formed in said outer surfaces of said strut portions; wherein said piston skirt portions are tapered so as to increase in thickness in the longitudinal direction of said piston from a lower end of said skirt portions toward said piston head as measured in a longitudinal plane perpendicular to said pin bore axis; said piston skirt portion includes an outer wall and an inner wall, said inner wall being set at an angle with respect to said outer wall to provide a continuously increasing said thickness in the longitudinal direction away from said lower end of said skirt portions; and wherein said angle is set at less than 3°.