US3579221A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Alarm system
Assignee: Individual
•
Filing: 1968-05-31
•
Granted: 1971-05-18
•
Expires: 1988-05-31
Abstract
Abstract An alarm system for use in conjunction with a radio actuated location system in which a security guard or watchman carries a radio transmitter which transmits signals according to the location of the guard, the alarm system including circuitry to generate an alarm frequency, the guard having a switch (which may operate automatically if he is incapacitated) which, when actuated, causes the alarm frequency to be transmitted (or cut off if it is normally being transmitted).
Inventors
- 👤 John Raymond Ashley
- 👤 Colin Grahame Douglas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 02:10
CPC Classifications
G; G07; G07C; G07C1/00; G07C1/20
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
123 words
In a portable radio transmitter comprising a modulator and, associated with the modulator, a coupling element which is movable into and out of electrical coupling association with a stationary frequency-determining conditioning instrument to apply to the modulator a modulating signal frequency determined by the frequency-determining conditioning instrument, the provision of an alarm frequency generating circuit coupled to the modulator to generate a radiated alarm frequency, a manually engageable twostate switch connected to the alarm frequency generating circuit to switch on the alarm frequency in one state of the switch and to switch off the alarm frequency in the other state of the switch, and spring biassing means engaging the switch to bias the switch into one state when the switch is manually disengaged.
Claim 2
Dependent Claim
123 words
In a portable radio transmitter comprising a modulator and, associated with the modulator, a coupling element which is movable into and out of electrical coupling association with a stationary frequency-determining conditioning instrument to apply to the modulator a modulating signal frequency determined by the frequency-determining conditioning instrument, the provision of an alarm frequency generating circuit coupled to the modulator to generate a radiated alarm frequency, a manually engageable twostate switch connected to the alarm frequency generating circuit to switch on the alarm frequency in one state of the switch and to switch off the alarm frequency in the other state of the switch, and spring biassing means engaging the switch to bias the switch into one state when the switch is manually disengaged.
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) | 1974-05-17 | 1974-11-16 | 1975-05-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-17 | 1978-11-16 | 1979-05-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-17 | 1982-11-16 | 1983-05-18 | $7700.00 | Window Closed / Lapsed |