US3763482A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Coaxial cable transducer
Assignee: GTE Sylvania Inc
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Filing: 1971-02-01
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Granted: 1973-10-02
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Expires: 1991-02-01
Abstract
Abstract A coaxial cable with a dielectric filler comprising a radially polarized electret develops and transmits a signal along the cable in response to deformation of the cable at any point along its length. Such a cable, when clamped to chain link, barbed wire, or similar fences, generates an electrical signal in response to attempts of intruders to climb or cut the fence and transmits that signal to remote alarm equipment. Standard coaxial cable is modified to form such a transducer by heating the entire cable, applying a dc potential across the ends of the outer and inner conductors while the dielectric filler is heat-softened, cooling the cable while maintaining the electrical stress on it, and finally removing the bias voltage. Signal amplification and processing eletronics, which are connected to the cable, detect intrusions and discriminate against false alarm signals.
Inventors
- 👤 C Burney
- 👤 V Pazemenas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 16:04
CPC Classifications
G; G08; G08B; G08B13/00; G08B13/02; G08B13/12; G08B13/122; H; H01; H01B; H01B11/00; H01B11/18; H01B11/1834; H10; H10N; H10N30/00; H10N30/60
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
26 words
A transducer comprising a coaxial cable having an inner conductor and an outer conductor and a dielectric filler between said conductors, said filler comprising an electret.
Claim 2
Dependent Claim
26 words
A transducer comprising a coaxial cable having an inner conductor and an outer conductor and a dielectric filler between said conductors, said filler comprising an electret.
Claim 3
Dependent Claim
12 words
The transducer according to claim 1 in which said filler is tetrafluoroethylene.
Claim 4
Dependent Claim
51 words
The transducer according to claim 1 in combination with means mechanically coupled to the exterior of said cable and responsive to a condition to be detected for changing the spacing of conductors, and detector means electrically connected across said conductors for detecting an electrical signal generated by said changed conductor spacing.
Claim 5
Dependent Claim
23 words
The transducer according to claim 1 in which said electret is polarized in the direction of a unidirectional field applied across said conductors.
Claim 6
Independent Claim
108 words
A system for detecting intrusion of a protected area comprising in combination, a coaxial cable disposed across said area, said cable having inner and outer conductors and an intermediate dielectric filler comprising an electret formed by a pre-applied unidirectional electric field across said conductors, inducer means for changing the relative radial spacing of said conductors in at least one point along the length of the cable in response to a condition of attempted intrusion of said area whereby to generate an electrical signal across said conductors, and detector means responsive to said electrical signal remote from said one point for producing an output indicative of the attempted intrusion.
Claim 7
Independent Claim
108 words
A system for detecting intrusion of a protected area comprising in combination, a coaxial cable disposed across said area, said cable having inner and outer conductors and an intermediate dielectric filler comprising an electret formed by a pre-applied unidirectional electric field across said conductors, inducer means for changing the relative radial spacing of said conductors in at least one point along the length of the cable in response to a condition of attempted intrusion of said area whereby to generate an electrical signal across said conductors, and detector means responsive to said electrical signal remote from said one point for producing an output indicative of the attempted intrusion.
Claim 8
Dependent Claim
28 words
The system according to claim 5 in which said detector means has a bandpass circuit whereby to produce said output only in response to signals generated by intruders.
Claim 9
Dependent Claim
40 words
The system according to claim 5 including a fence comprising wire strands, said inducer means comprising clamping rings tightly mechanically connecting said cable to said wire strands whereby vibrations in said strands are converted by said cable into electrical signals.
Claim 10
Dependent Claim
25 words
The system according to claim 5 in which said cable is buried under the earth''s surface, said inducer means comprising earth material surrounding the cable.
Claim 11
Dependent Claim
43 words
The system according to claim 7 which includes a station located remote from said fence and having an alarm generator, said detector means being disposed adjacent to said fence and being electrically connected to said station whereby said output activates said alarm generator.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-10-01 | 1977-04-02 | 1977-10-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-01 | 1981-04-02 | 1981-10-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-01 | 1985-04-02 | 1985-10-02 | $7700.00 | Window Closed / Lapsed |