US3205352A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Presence detector
Assignee: General Precision Inc
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Filing: 1961-08-04
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Granted: 1965-09-07
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Expires: 1981-08-04
Abstract
No abstract record available.
Inventors
- 👤 Prucha Martin John
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 03:59
CPC Classifications
G; G08; G08G; G08G1/00; G08G1/01; G08G1/042; B; B61; B61L; B61L1/00; B61L1/02; B61L1/10; B61L29/00; B61L29/24; B61L29/28; B61L29/282
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
154 words
APPARATUS FOR SENSING THE PRESENCE OF A METALLIC MASS, SAID APPARATUS COMPRISING A FIRST OSCILLATOR INCLUDING AN INDUCTIVE LOOP, SAID LOOP BEING OPERABLE TO VARY IN INDUCTANCE VALUE WHEN A METALLIC MASS ENTERS THE FIELD THEREOF TO VARY THE FREQUENCY OF THE FIRST OSCILLATOR FROM A NORMAL VALUE, A SECOND OSCILLATOR FOR GENERATING A REFERENCE FREQUENCY SUBSTANTIALLY EQUAL TO THE NORMAL FREQUENCY OF THE FIRST OSCILLATOR WITH NO METALLIC MASS IN THE FIELD OF THE LOOP, A BEAT FREQUENCY DETECTOR COUPLED TO BOTH OSCILLATORS AND OPERABLE TO GENERATE A BEAT FREQUENCY SIGNAL WHEN THE FREQUENCY OF THE FIRST OSCILLATOR VARIES FROM THE NORMAL FREQUENCY, RECTIFYING MEANS COUPLED TO THE BEAT FREQUENCY DETECTOR FOR GENERATING A DIRECT VOLTAGE WHEN THE FREQUENCY OF THE FIRST OSCILLATOR VARIES FROM THE NORMAL VALUE, AND AN OUTPUT SWITCHING MEANS COUPLED TO THE RECTIFYING MEANS, SAID SWITCHING MEANS INCLUDING A POSITIVE FEEDBACK PATH TO RENDER THE SWITCHING MEANS PARTIALLY SELF-SUSTANINING.
Claim 2
Dependent Claim
154 words
APPARATUS FOR SENSING THE PRESENCE OF A METALLIC MASS, SAID APPARATUS COMPRISING A FIRST OSCILLATOR INCLUDING AN INDUCTIVE LOOP, SAID LOOP BEING OPERABLE TO VARY IN INDUCTANCE VALUE WHEN A METALLIC MASS ENTERS THE FIELD THEREOF TO VARY THE FREQUENCY OF THE FIRST OSCILLATOR FROM A NORMAL VALUE, A SECOND OSCILLATOR FOR GENERATING A REFERENCE FREQUENCY SUBSTANTIALLY EQUAL TO THE NORMAL FREQUENCY OF THE FIRST OSCILLATOR WITH NO METALLIC MASS IN THE FIELD OF THE LOOP, A BEAT FREQUENCY DETECTOR COUPLED TO BOTH OSCILLATORS AND OPERABLE TO GENERATE A BEAT FREQUENCY SIGNAL WHEN THE FREQUENCY OF THE FIRST OSCILLATOR VARIES FROM THE NORMAL FREQUENCY, RECTIFYING MEANS COUPLED TO THE BEAT FREQUENCY DETECTOR FOR GENERATING A DIRECT VOLTAGE WHEN THE FREQUENCY OF THE FIRST OSCILLATOR VARIES FROM THE NORMAL VALUE, AND AN OUTPUT SWITCHING MEANS COUPLED TO THE RECTIFYING MEANS, SAID SWITCHING MEANS INCLUDING A POSITIVE FEEDBACK PATH TO RENDER THE SWITCHING MEANS PARTIALLY SELF-SUSTANINING.
References Cited (Backward Citations)
GB222369A
Cited
US2105930A
Cited
US2390221A
Cited
US2421771A
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US2355395A
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US2454687A
Cited
GB656366A
Cited
US2704339A
Cited
US2646559A
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US2652551A
Cited
US2670434A
Cited
GB719179A
Cited
US2943306A
Cited
US2917732A
Cited
FR1203211A
Cited
US3164802A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1968-09-06 | 1969-03-08 | 1969-09-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1972-09-06 | 1973-03-08 | 1973-09-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1976-09-06 | 1977-03-08 | 1977-09-07 | $7700.00 | Window Closed / Lapsed |