Flexible self-limiting heating cable
AssigneeSunbeam Corporation
InventorGeorge C. Crowley
Life of this patent
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Abstract
A heating cable having spaced helically wound conductor wires separated by a layer of positive temperature coefficient material which functions as a self-limiting heating element. At least one of the conductor wires is helically disposed on a stranded core of insulating fibers which have been coated and impregnated with conductive carbon.
Claims6
In an electric blanket, a heating cable comprising a pair of elongated spaced conductors supported in spaced relation by a positive temperature coefficient material which serves as resistance heating means for said cable, each of said conductors includes a core of nonconducting flexible threads and a helically disposed ribbon of low resistance material wound on said core, said core of threads being impregnated with conducting carbon which provides a low resistance path lengthwise of said conductors on the inside diameter of said helically wound ribbon of material, said PTC material being extruded over said spaced conductors, and at least one insulating coating being extruded over said PTC material.
In an electric blanket, a heating cable comprising a pair of elongated spaced conductors supported in spaced relation by a positive temperature coefficient material which serves as resistance heating means for said cable, one of said conductors includes a core of nonconducting flexible threads and a helically disposed ribbon of low resistance material wound on said core, said core of threads being impregnated with conducting carbon which provides a low resistance path lengthwise of said conductors on the inside diameter of said helically wound ribbon of material, said PTC material being extruded over said one conductor, and at least one insulating coating being extruded over said PTC material and said conductors.
Dependencies are inferred from the claim text.