US3789130A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tamper proof electrical cables
Assignee: Pyrotenax Ltd
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Filing: 1969-10-10
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Granted: 1974-01-29
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Expires: 1989-10-10
Abstract
Abstract An electric power or communication cable incorporates a mineral insulated cable of a cross-section that is small in comparison with the overall cross-section of the cable, a conductor or conductors of the mineral insulated cable being adapted to carry a signal other than the normal power or signalling load of the power or communication cable. Preferably the or each mineral insulated cable is so located in the cable that it is not easily recognized as an alarm circuit by a thief. In an electric power cable having armouring or a concentric screen or neutral conductor comprising wires applied as a continuous helical lapping or with periodically reversing lay one or more of the wires may be replaced by a mineral insulated cable.
Inventors
- 👤 H Parker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 19:47
CPC Classifications
H; H01; H01B; H01B7/00; H01B7/32; H01B7/16
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
78 words
An electric cable comprising at least one core for carrying the normal load of the electric cable and, as an element of the cable, a mineral insulated cable having at least one conductor and a metal sheath, which mineral insulated cable is of a crosssection that is small in comparison with the overall crosssection of the electric cable and has at least one conductor adapted to carry a signal other than the normal load of the electric cable.
Claim 2
Dependent Claim
78 words
An electric cable comprising at least one core for carrying the normal load of the electric cable and, as an element of the cable, a mineral insulated cable having at least one conductor and a metal sheath, which mineral insulated cable is of a crosssection that is small in comparison with the overall crosssection of the electric cable and has at least one conductor adapted to carry a signal other than the normal load of the electric cable.
Claim 3
Dependent Claim
101 words
An electric cable comprising at least one core for carrying the normal load of the electric cable and, as an element of the cable, a mineral insulated cable having at least one conductor and a metal sheath, which mineral insulated cable is of cross-section that is small in comparison with the overall cross-section of the electric cable and has at least one conductor adapted to carry a signal other than the normal load of the electric cable, the mineral insulated cable being so located in the electric cable that it is not easily recognized as an alarm circuit by a thief.
Claim 4
Dependent Claim
101 words
An electric cable comprising at least one core for carrying the normal load of the electric cable and, as an element of the cable, a mineral insulated cable having at least one conductor and a metal sheath, which mineral insulated cable is of cross-section that is small in comparison with the overall cross-section of the electric cable and has at least one conductor adapted to carry a signal other than the normal load of the electric cable, the mineral insulated cable being so located in the electric cable that it is not easily recognized as an alarm circuit by a thief.
Claim 5
Dependent Claim
81 words
An electric power cable comprising at least one core and, helically applied about the core, a layer of wires, wherein a mineral insulated cable having at least one conductor and a metal sheath constitutes an element of the layer of wires, the mineral insulated cable being of a cross-section that is small in comparison with the overall cross-section of the power cable and at least one conductor adapted to carry a signal other than the normal load of the power cable.
Claim 6
Dependent Claim
81 words
An electric power cable comprising at least one core and, helically applied about the core, a layer of wires, wherein a mineral insulated cable having at least one conductor and a metal sheath constitutes an element of the layer of wires, the mineral insulated cable being of a cross-section that is small in comparison with the overall cross-section of the power cable and at least one conductor adapted to carry a signal other than the normal load of the power cable.
Claim 7
Dependent Claim
32 words
An electric power cable as claimed in claim 3, in which the sheath of the mineral insulated cable is of the same external diameter as a wire of the layer of wires.
Claim 8
Dependent Claim
40 words
An electric power cable as claimed in claim 4, in which at least the outer surface of the sheath of the mineral insulated cable is of a material that is the same as that of the surface of each wire.
Claim 9
Dependent Claim
37 words
An electriC power cable as claimed in claim 4, in which at least the outer surface of the sheath of the mineral insulated cable is of a material that resembles that of the surface of each wire.
Claim 10
Dependent Claim
22 words
An electric power cable as claimed in claim 3, in which the layer of wires constitutes the armouring of the power cable.
Claim 11
Dependent Claim
23 words
An electric power cable as claimed in claim 3, in which the layer of wires constitutes a neutral conductor of the power cable.
Claim 12
Dependent Claim
23 words
An electric power cable as claimed in claim 3, in which the layer of wires constitutes a concentric screen of the power cable.
Claim 13
Dependent Claim
83 words
A multi-core electric power cable having at least two cores for carrying the normal load of the power cable and as one core of the power cable a mineral insulated cable which has a metal sheath and at least one conductor adapted to carry a signal other than the normal load of the power cable, the core constituted by the mineral insulated cable being of substantially the same overall diameter as each of the cores carrying the normal load of the power cable.
Claim 14
Dependent Claim
83 words
A multi-core electric power cable having at least two cores for carrying the normal load of the power cable and as one core of the power cable a mineral insulated cable which has a metal sheath and at least one conductor adapted to carry a signal other than the normal load of the power cable, the core constituted by the mineral insulated cable being of substantially the same overall diameter as each of the cores carrying the normal load of the power cable.
Claim 15
Dependent Claim
27 words
A multi-core electric power cable as claimed in claim 10, in which the sheath of the mineral insulated cable constitutes the neutral conductor of the power cable.
Claim 16
Dependent Claim
28 words
A multi-core electric power cable as claimed in claim 10, in which the sheath of the mineral insulated cable constitutes the earth continuity conductor of the power cable.
References Cited (Backward Citations)
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US2341235A
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US2912600A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-01-28 | 1977-07-30 | 1978-01-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-28 | 1981-07-30 | 1982-01-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-28 | 1985-07-30 | 1986-01-29 | $7700.00 | Window Closed / Lapsed |