US3757086A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical heating cable
Assignee: Individual
•
Filing: 1972-10-05
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Granted: 1973-09-04
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Expires: 1992-10-05
Abstract
Abstract An electrical heating cable having at least two low-resistance current-carrying wires and a high-resistance, heating wire spirally wound about the current-carrying wires; in one embodiment, the current-carrying wires are bared at spaced intervals so that the high-resistance wire makes electrical contact at the bared points with one of the current-carrying wires at each interval. In another embodiment, a plurality of copper foil wraps surrounds both insulated, current-carrying wires at spaced intervals and the high-resistance, heating wire is spirally wound over the current-carrying wires and the copper foil wraps. A staple is driven through the insulation and one of the current-carrying wires at each interval so that electrical connection is made between the current-carrying wire and the heating wire at that interval. The construction permits the user to cut the cable to any length and still maintain the same current flow in any given length for the same applied voltage.
Inventors
- 👤 W Indoe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 06:15
CPC Classifications
H; H05; H05B; H05B3/00; H05B3/40; H05B3/54; H05B3/56
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
284 words
An electrical heating cable which maintains the same current flow for any given applied voltage in each section of predetermined length regardless of the total length of the cable comprising: first and second electrically conductive, low-resistance wires in proximity with each other; an electrical insulator surrounding each low-resistance wire and electrically insulating the low-resistance wires from one another; a plurality of first strips of conductive metallic foil wound around the electrical insulator and the low-resistance wires therein and spaced therealong; a plurality of second strips of conductive metallic foil wound around the electrical insulator and the low-resistance wires therein and spaced therealong; said first and second strips of conductive metallic foil being spaced from one another and being located alternately along the length of the low-resistance wires such that each first strip has a corresponding next-consecutive second strip adjacent thereto; a high resistance wire wound spirally over the insulator and the first and second strips of foil along the length of the lowresistance wires so that electrical contact is made between the foil strips and the high-resistance wire; a plurality of first staples, each first staple overlying a corresponding first foil strip and extending through the insulator to make electrical contact between said first foil strip and the first low-resistance wire; a plurality of second staples, each second staple overlying a corresponding second foil strip and extending through the insulator to make electrical contact between said second foil strip and the second low-resistance wire, whereby current will flow in the high-resistance wire to produce heat therefrom when an electric voltage is applied across the low-resistance wires; and an outer insulating covering surrounding the combination of the spirally wound, high-resistance wire and the low-resistance wires.
Claim 2
Dependent Claim
284 words
An electrical heating cable which maintains the same current flow for any given applied voltage in each section of predetermined length regardless of the total length of the cable comprising: first and second electrically conductive, low-resistance wires in proximity with each other; an electrical insulator surrounding each low-resistance wire and electrically insulating the low-resistance wires from one another; a plurality of first strips of conductive metallic foil wound around the electrical insulator and the low-resistance wires therein and spaced therealong; a plurality of second strips of conductive metallic foil wound around the electrical insulator and the low-resistance wires therein and spaced therealong; said first and second strips of conductive metallic foil being spaced from one another and being located alternately along the length of the low-resistance wires such that each first strip has a corresponding next-consecutive second strip adjacent thereto; a high resistance wire wound spirally over the insulator and the first and second strips of foil along the length of the lowresistance wires so that electrical contact is made between the foil strips and the high-resistance wire; a plurality of first staples, each first staple overlying a corresponding first foil strip and extending through the insulator to make electrical contact between said first foil strip and the first low-resistance wire; a plurality of second staples, each second staple overlying a corresponding second foil strip and extending through the insulator to make electrical contact between said second foil strip and the second low-resistance wire, whereby current will flow in the high-resistance wire to produce heat therefrom when an electric voltage is applied across the low-resistance wires; and an outer insulating covering surrounding the combination of the spirally wound, high-resistance wire and the low-resistance wires.
Claim 3
Dependent Claim
16 words
The invention of claim 1 including an outer, electrically conductive shield surrounding the outer insulated covering.
Claim 4
Dependent Claim
127 words
The invention of claim 8 including: a third electrically conductive, low-resistance wire in proximity with said first and second low-resistance wires and surrounded by said insulator; a plurality of third strips of conductive metallic foil wound around the insulator and the low-resistance wires therein and spaced therealong, the high-resistance wire being wound over the third strips of foil; said first, second and third strips of conductive metallic foil being spaced from one another and being located along the length of the low-resistance wires such that consecutive first and second adjacent strips have a corresponding next-consecutive third strip adjacent thereto; and a third staple overlying a third foil strip and extending through the insulator to make electrical contact between said third foil strip and the third low-resistance wire.
Claim 5
Dependent Claim
16 words
The invention of claim 3 including an outer, electrically conductive shield surrounding the outer insulated covering.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-09-03 | 1977-03-05 | 1977-09-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-03 | 1981-03-05 | 1981-09-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-03 | 1985-03-05 | 1985-09-04 | $7700.00 | Window Closed / Lapsed |