Bimetal actuator with electrical resistance heater

Claim 2

A bimetal actuator comprising a bimetal element with support means fixing a portion thereof so that another portion moves relative to the support means when the element warps and a thin flexible resistance heater bonded to the high expansion side of said element, said heater comprising a thin, flexible, insulating film and a thin, narrow, flexible, metallic, electrical resistance element bonded to one side thereof, the other side of said film being bonded to the high expansion side of said bimetallic element, said insulating film including portions thereof extending freely from said bimetal element, and said resistance element including integral lead portions at the ends thereof, which lead portions are considerably wider than said resistance element and coextend with and are bonded to said freely extending film portions thereby to provide integral flexible leads.

Claim 3

The bimetal actuator claimed in claim 1 in which said electrical resistance element further includes integral conductor portions between the ends thereof and said integral lead portions, which conductor portions are wider than said resistance element and narrower than said lead portions and in which said conductor portions overlie and are bonded to those portions of said film which are bonded to said bimetal element.

Claim 4

The bimetal actuator claimed in claim 1 including a second thin insulating film overlying and bonded to said resistance heating element, to the exposed surfaces of said insulating film, and to Adjacent surfaces of said bimetal element.

Claim 5

A bimetal actuator comprising an elongated bimetal strip having a thin, flexible, electrical resistance heater bonded to the high expansion side thereof, said heater comprising a thin elongated strip of insulating film lying longitudinally along the high expansion side of said bimetal strip and a thin, flexible, metallic, electrical resistance element bonded to one side of said film, the other side of said film being bonded to said bimetal element, said flexible insulating film including end portions thereof extending laterally from said bimetal strip, said electrical resistance element having a high resistance portion comprising a thin, long, relatively narrow, metallic strip lying in a generally serpentine pattern with elongated transversely extending and closely spaced parallel portions joined by short portions, and relatively wide integral end portions extending laterally from said bimetal strip and bonded to said laterally extending film portions, thereby to provide integral flexible leads of relatively low resistance.

Claim 6

A bimetal actuator comprising an elongated bimetal strip having a thin, flexible, electrical resistance heater bonded to the high expansion side thereof, said heater comprising a thin elongated strip of insulating film lying longitudinally along the high expansion side of said bimetal strip and a thin, flexible, metallic, electrical resistance element bonded to one side of said film, the other side of said film being bonded to said bimetal element, said flexible insulating film including end portions thereof extending laterally from said bimetal strip, said electrical resistance element having a high resistance portion comprising a thin, long, relatively narrow, metallic strip lying in a generally serpentine pattern with elongated transversely extending and closely spaced parallel portions joined by short portions, and relatively wide integral end portions extending laterally from said bimetal strip and bonded to said laterally extending film portions, thereby to provide integral flexible leads of relatively low resistance.

Claim 7

The bimetal actuator claimed in claim 4 in which said insulating film is a high temperature resistant plastic film and in which said film is bonded to said bimetal element with a high temperature resistant adhesive.