Tocco, Inc.

John R Laughlin

George M Mucha

William Z Nelson

Robert C Johnson

Method and apparatus for inductively heating and quench hardening axially spaced cams on a steel camshaft having a longitudinally extending rotational axis concentric with a plurality of axially spaced bearings, which method and apparatus utilizes an induction heating coil having an inner surface surrounding the rotational axis of the camshaft with an insulating gap and integral quench openings for directing quenching liquid inwardly from the heating coil for the workpiece, and a high frequency power supply for selectively energizing the heating coil with a power density within the heating coil of about 20KW/in.sup.2 and an auxiliary cooling assembly fixed with respect to the heating coil and including an arrangement for spraying a cooling liquid toward the camshaft. In accordance with the method and apparatus, a camshaft is indexed axially through the opening of the coil and cooling assembly to a first position with a cam within the coil, at which position the camshaft is indexed to have the lobe of the cam facing the gap in the induction heating coil and a hardening cycle is then employed including induction heating of the surface of the camshaft while the cam is stationary and then quench hardening by directing a quenching fluid through the induction heating coil toward the previously heated cam surface. After this heating cycle, the camshaft is then moved until the next cam is within the heating coil and the previously hardened cam is in the cooling assembly. Thereafter, another hardening cycle occurs. This process is repeated until all cams have been hardened.

Method and apparatus for hardening axially spaced cams on a camshaft

A method and apparatus for heat treating camshafts includes a retractable shield positioned between a previously hardened surface and a surface being heat treated. During the induction heating and quenching cycle, a coolant is delivered to the hardened surface to maintain the temperature thereof below the tempering temperature. The shield prevents the coolant from contacting the unhardened surface and interfering with the heating and quenching thereof.

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Broadview Heights, OH, United States of America

John R Laughlin