Patent US3564501A successfully refreshed from Google Patents.
US3564501A
Expired / Lapsed
US
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Frequency controlled door locks
Assignee: Individual
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Filing: 1967-09-21
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Granted: 1971-02-16
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Expires: 1987-09-21
Abstract
Abstract AN ELECTRONIC ACTUATING ARRANGEMENT INCLUDES BOTH TRIGGERING MEANS FOR OPERATING AN ACTUATING DEVICE SUCH AS TO PERMIT THE OPENING OF A DOOR, AND LOCKOUT MEANS FOR PREVENTING OPERATION OF THE TRIGGERING MEANS IN THE ABSENCE OF AN INPUT SIGNAL OF PRECISELY PREDETERMINED FREQUENCY, OR IN THE PRESENCE OF INCORRECT SIGNALS. AN AMPLIFIER IS PROVIDED WHICH MAY INCORPORATE A QUARTZ CRYSTAL RESONATOR FILTER WHICH HAS EITHER A PEAK OR A NULL CHARACTERISTIC AT A PREDETERMINED FREQUENCY. WHEN THE RESONATOR HAS THE NULL CHARACTERISTIC, THE FILTER IS USED IN THE LOCKOUT CHANNEL OF THE ARRANGEMENT. WHEN IT HAS THE PEAK CHARACTERISTIC THE FILTER IS USED IN THE ACTUATE CHANNEL.
Inventors
- 👤 William M Flook Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 21:34
CPC Classifications
G; G08; G08C; G08C19/00; G08C19/12; G07; G07C; G07C9/00; G07C9/00174; G07C9/00182; G07C2009/00753; G07C2009/00769; G07C2009/00777; G07C2009/00793
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) | 1974-02-15 | 1974-08-17 | 1975-02-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-15 | 1978-08-17 | 1979-02-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-15 | 1982-08-17 | 1983-02-16 | $7700.00 | Window Closed / Lapsed |