Abstract A hair curler employing a heater element formed of a conductive crystalline polymer is disclosed. The polymer, loaded with conductive particles, such as carbon black, has a positive temperature coefficient (PTC) of resistance characteristic and combines a fast warmup time with a slow cooldown time due to the phase change of amorphous polymer to crystalline upon cooling, yet does not become molten due to the sharp rise in resistance at temperatures above an anomaly temperature which limits the heat generation at elevated temperatures. Since the polymer retains its shape, no special sealing means is required to confine it as in prior art fusible wax devices. The heater element is an elongated annulus coated with conductive material on inner and outer peripheral surfaces. A sheet of conductive material is rolled into a cylinder and pressed into the bore of the annulus with a terminal extending therefrom. A sleeve of conductive material is placed about the annulus and a terminal attached to the sleeve to complete electrical connection. The outer shell of the curler extends over the terminal to provide a protected environment.
Inventors
👤 John R D Entremont
Bibliographic Details
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-10-23 09:38
CPC Classifications
A; A45; A45D; A45D2/00; A45D2/36
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
30 words
A hair curler according to claim 1 in which the inner conductor is of greater thickness than the outer conductor and extends substantially along the length of the heating element.
Claim 2
Dependent Claim
18 words
A hair curler according to claim 2 in which the inner conductor is slit along its axial length.
Claim 3
Dependent Claim
32 words
A hair curler according to claim 1 in which the outer conductor is formed with an inwardly extending radial flange and the second terminal extends from the inner portion of the flange.
Claim 4
Dependent Claim
24 words
A hair curler according to claim 4 in which a washer of electrically insulative material is interposed between the flange and the heating element.
Claim 5
Dependent Claim
23 words
A hair curler according to claim 1 in which the outer shell extends axially beyond the first and second terminals and the disc.
Claim 6
Dependent Claim
156 words
An electrically heated hair curler comprising a generally cylindrical outer shell of polymeric material; a generally cylindric tubular heating element having an electrically conductive coating on inner and outer peripheral surfaces, the coatings being electrically insulated from one another, the heating element being located within the outer shell in good heat-transfer relation therewith; an inner conductor formed for a generally tubular cylinder of electrically conductive material and having an axially extending slit pressed into the bore of the heating element and in electrical connection with the coating on the inner peripheral surface of the heating element; an outer conductor formed of electrically conductive material received on the outer peripheral surface and held tightly thereagainst and in electrical connection with the coating on the outer peripheral surface of the heating element, the outer and inner conductors being electrically insulated from one another; and terminal means attached to the inner and outer conductors to provide electrical connection therewith.