US3559201A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Security system
Assignee: General Atronics Corp
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Filing: 1967-01-03
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Granted: 1971-01-26
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Expires: 1987-01-03
Abstract
Abstract AN OSCILLATOR DRIVING A COIL ESTABLISHES AN ELECTRIC FIELD BETWEEN THAT COIL AND A SECOND COIL GENERALLY PERPENDICULAR THERETO. DISTURBANCES OF THIS FIELD BY PASSAGE OF AN ELECTRICALLY CONDUCTIVE OBJECT ARE FED BACK FROM THE SEC- OND COIL TO VARY THE OSCILLATOR PHASE OR FREQUENCY, AND THE RESULTING VARIATIONS ARE UTILIZED TO INDICATE SUCH OBJECT PASSAGE.
Inventors
- 👤 Robert C Hilliard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 19:29
CPC Classifications
G; G01; G01V; G01V3/00; G01V3/08; G01V3/10; G01V3/104; G01V3/108; G08; G08B; G08B13/00; G08B13/22; G08B13/24; G08B13/2402; G08B13/2465; G08B13/2468; G08B13/2474
Claims Analysis
Total Claims: 0
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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) | 1974-01-25 | 1974-07-27 | 1975-01-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-01-25 | 1978-07-27 | 1979-01-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-01-25 | 1982-07-27 | 1983-01-26 | $7700.00 | Window Closed / Lapsed |