Patent US4348584A successfully refreshed from Google Patents.
US4348584A
Expired / Lapsed
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Flexible heating elements and processes for the production thereof
Assignee: Sunbeam Products Inc
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Filing: 1980-05-09
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Granted: 1982-09-07
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Expires: 2000-05-09
Abstract
Abstract A flexible heating element comprises at least two flexible electrical conductors spaced apart by a PTC material, an amorphous highly conductive rubber compatible with the PTC material and adhered to each conductor being interposed between the PTC material and each conductor whereby in use current passes from one conductor to another through the PTC material via the highly conductive rubber. The conductors are spaced sufficiently close to one another to ensure that when energised the PTC material heats substantially uniformly without exhibiting a significant temperature gradient between the conductors and that any abnormal temperature increase increases the temperature of all the PTC material between the conductors in the region of the abnormal temperature increase. The arrangement is such that in use the contact resistance between the conductors and the PTC material is reduced by the amorphous highly conductive rubber interposed therebetween. The flexible heating element is produced by extruding the amorphous highly conductive rubber to cover each flexible electrical conductor and subsequently or simultaneously extruding the PTC material to cover the amorphous highly conductive rubber.
Inventors
- 👤 George M. Gale
- 👤 David I. James
- 👤 John V. B. Meyer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 15:45
CPC Classifications
H; H05; H05B; H05B3/00; H05B3/40; H05B3/54; H05B3/56; B; B29; B29C; B29C48/00; B29C48/15; B29C48/156; H01; H01C; H01C7/00; H01C7/02; H01C7/027; H05B3/10; H05B3/12; H05B3/14; H05B3/146; B29C48/03; B29C48/12; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49082; Y10T29/49083
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
158 words
A flexible heating element which comprises at least two flexible electrical conductors spaced apart by a PTC material, an amorphous highly conductive rubber compatible with the said PTC material and adhered to and completely surrounding each conductor, said conductive rubber being interposed between the PTC material and each conductor whereby in use current passes from one conductor to another through the PTC material via the said highly conductive rubber, said conductors and said conductive rubber which coats said conductors being completely enveloped by said PTC material, the conductors being spaced sufficiently close to one another to ensure that when energized the PTC material heats substantially uniformly without exhibiting a significant temperature gradient between the conductors and that any abnormal temperature increase increases the temperature of all the PTC material between the conductors in the region of the abnormal temperature increase, the amorphous highly conductive rubber interposed therebetween providing improved current conduction between the conductors and said PTC material.
Claim 2
Dependent Claim
158 words
A flexible heating element which comprises at least two flexible electrical conductors spaced apart by a PTC material, an amorphous highly conductive rubber compatible with the said PTC material and adhered to and completely surrounding each conductor, said conductive rubber being interposed between the PTC material and each conductor whereby in use current passes from one conductor to another through the PTC material via the said highly conductive rubber, said conductors and said conductive rubber which coats said conductors being completely enveloped by said PTC material, the conductors being spaced sufficiently close to one another to ensure that when energized the PTC material heats substantially uniformly without exhibiting a significant temperature gradient between the conductors and that any abnormal temperature increase increases the temperature of all the PTC material between the conductors in the region of the abnormal temperature increase, the amorphous highly conductive rubber interposed therebetween providing improved current conduction between the conductors and said PTC material.
Claim 3
Dependent Claim
16 words
A heating element as claimed in claim 1 wherein the PTC material comprises high density polyethylene.
Claim 4
Dependent Claim
18 words
A heating element as claimed in claim 1 wherein the amorphous highly conductive rubber comprises an epichlorohydrin rubber.
Claim 5
Dependent Claim
24 words
A heating element as claimed in claim 3 wherein the amorphous highly conductive rubber contains about 65% epichlorohydrin rubber and about 35% ethylene oxide.
Claim 6
Dependent Claim
24 words
A heating element as claimed in claim 1 wherein a layer of graphite is interposed between the amorphous highly conductive rubber and the conductor.
Claim 7
Dependent Claim
53 words
A heating element as claimed in claim 1, said element having a substantially dumb-bell shaped cross section having two lobe portions, each said flexible electrical conductor being spiralled around a core of electrically insulating material and one of said flexible electrical conductors being positioned in each of said lobe portions of the dumb-bell.
Claim 8
Dependent Claim
56 words
A heating element as claimed in claim 6 wherein one of said flexible electrical conductors is spiralled around one core of electrically insulating material in one direction in one of said lobe portions and the other flexible electrical conductor is spiralled around the other core in the opposite direction in the other of said lobe portions.
References Cited (Backward Citations)
US2745944A
Cited
US3410984A
Cited
US4060710A
Cited
US3861029A
Cited
US3858144A
Cited
US3823217A
Cited
US4074222A
Cited
US4177376A
Cited
US4246468A
Cited
GB2024579A
Cited
US4307290A
Cited
US4200973A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-09-06 | 1986-03-08 | 1986-09-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-09-06 | 1990-03-08 | 1990-09-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-09-06 | 1994-03-08 | 1994-09-07 | $7700.00 | Window Closed / Lapsed |