Thomas A Himes

US Patent:

54323223, Jul 11, 1995

Filed:

Nov 13, 1992

Appl. No.:

7/974744

Inventors:

Aaron N. Ingram - Canton GA
Richard A. Wise - Marietta GA
John W. Carroll - Winston-Salem NC
Thomas C. Himes - Conyers GA

Assignee:

Bruder Healthcare Company - Marietta GA

International Classification:

H05B 336

US Classification:

219528

Abstract:

The improved heating pad includes a flexible, thin film heating element with two independent semiconductor circuits printed on an electrically insulating surface, laminated between overlying and underlying organic polyester sheets, and electrically connected to an external power source, wherein the heating element is hermetically sealed in an outer organic polymer covering. Thermostats are positioned directly over the semiconductive circuit traces. The circuit traces are connected in parallel by a multi-position switch, with each circuit capable of being energized separately or in combination, and each circuit capable of providing heat over the entire area of the pad. A circuit protective device provides a varistor across the power supply and a fast-acting fuse in series with the circuit traces.