Patent EP0113520A2 successfully refreshed from Google Patents.
US4074249A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic detection means
Assignee: Sentry Technology Corp
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Filing: 1977-02-04
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Granted: 1978-02-14
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Expires: 1997-02-04
Abstract
Abstract Magnetic detection means for protection of articles such as books, records and the like, wherein a target, of magnetically soft or easily saturable magnetic material, such as permalloy foil, is mounted on the protected article and emits magnetic signals which are harmonics of an interrogating magnetic field generated at an exit station. The target is curved along its length and provides good signal response over a wide range of orientation.
Inventors
- 👤 Arthur J. Minasy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:01
CPC Classifications
G; G08; G08B; G08B13/00; G08B13/22; G08B13/24; G08B13/2402; G08B13/2405; G08B13/2408; G08B13/2411; G08B13/2428; G08B13/2434; G08B13/2437; G08B13/2465; G08B13/2468; G08B13/2474
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
102 words
A magnetic detection system comprising means forming an exit passageway from an enclosure, means for generating an interrogating magnetic field which varies at a given frequency in said passageway, at least one target secured to an article capable of being carried through said passageway, said target comprising an elongated strip of readily saturable magnetic material capable of producing magnetic fields at frequencies which are harmonics of the frequency of an incident magnetic field, said strip being curved along its length, and detection means arranged to detect magnetic fields in the vicinity of said passageway which vary at selected ones of said harmonics.
Claim 2
Dependent Claim
102 words
A magnetic detection system comprising means forming an exit passageway from an enclosure, means for generating an interrogating magnetic field which varies at a given frequency in said passageway, at least one target secured to an article capable of being carried through said passageway, said target comprising an elongated strip of readily saturable magnetic material capable of producing magnetic fields at frequencies which are harmonics of the frequency of an incident magnetic field, said strip being curved along its length, and detection means arranged to detect magnetic fields in the vicinity of said passageway which vary at selected ones of said harmonics.
Claim 3
Dependent Claim
15 words
A magnetic detection system according to claim 1 wherein said strip is of permalloy foil.
Claim 4
Dependent Claim
15 words
A magnetic detection system according to claim 1 wherein said strip is of semi-circular configuration.
Claim 5
Dependent Claim
14 words
A magnetic detection system according to claim 1 wherein said strip is crescent shaped.
Claim 6
Dependent Claim
16 words
A magnetic detection system according to claim 4 wherein said strip is tapered at its ends.
Claim 7
Dependent Claim
59 words
A target for a magnetic detection system of the type in which an alternating interrogating magnetic field is generated at an exit passageway and magnetic fields, which alternate at frequencies harmonically related to the interrogating field, are detected at said passageway, said target comprising an elongated strip of readily saturable magnetic material, said strip being curved along its length.
Claim 8
Dependent Claim
59 words
A target for a magnetic detection system of the type in which an alternating interrogating magnetic field is generated at an exit passageway and magnetic fields, which alternate at frequencies harmonically related to the interrogating field, are detected at said passageway, said target comprising an elongated strip of readily saturable magnetic material, said strip being curved along its length.
Claim 9
Dependent Claim
13 words
A target according to claim 6 wherein said strip is of permalloy foil.
Claim 10
Dependent Claim
13 words
A target according to claim 6 wherein said strip is of semi-circular configuration.
Claim 11
Dependent Claim
12 words
A target according to claim 6 wherein said strip is crescent shaped.
Claim 12
Dependent Claim
14 words
A target according to claim 9 wherein said strip is tapered at its ends.
Claim 13
Dependent Claim
30 words
A target according to claim 6 wherein said target includes an adhesive layer on each surface of said strip and a outer protective covering over one of said adhesive layers.
References Cited (Backward Citations)
FR763681A
Cited
US3747086A
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US3790945A
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US3665449A
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US3697996A
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Cited
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Cited
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US4000488A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-02-13 | 1981-08-15 | 1982-02-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-02-13 | 1985-08-15 | 1986-02-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-02-13 | 1989-08-15 | 1990-02-14 | $7700.00 | Window Closed / Lapsed |