US3683346A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable-tone electronic alarm system
Assignee: Individual
•
Filing: 1971-03-01
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Granted: 1972-08-08
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Expires: 1991-03-01
Abstract
Abstract An intrusion alarm having an audio oscillator capable of producing fixed or variable frequency tones wherein closing of an intrusion detection switch causes the oscillator to first deliver a fixed warning tone to a local loudspeaker, and after a time delay causes the oscillator to deliver a variable frequency alarm tone to the local and a remote loudspeaker in the event authorized deactivation of the alarm system does not take place before expiration of the time delay period. Fire and panic switches provide for immediate alarm tone signalling by bypassing the time delay circuit.
Inventors
- 👤 Charles A Horton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 13:04
CPC Classifications
G; G08; G08B; G08B3/00; G08B3/10; G08B13/00; G08B13/02; G08B13/08
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
236 words
A variable-tone electronic alarm system comprising: a pair of terminals; a variable-voltage source having a voltage control terminal; a variable-frequency oscillator having a frequency-control terminal, said oscillator producing a warning signal in the absence of a signal applied to said frequency-control terminal, and producing a variable-frequency alarm signal when a signal is applied to said frequency-control terminal; a time-delay network having an output terminal; means connecting said variable-voltage source, said variablefrequency oscillator, and said time-delay network in parallel circuit arrangement across said pair of terminals; means connecting the output of said variable-voltage source to said frequency-control terminal to control the frequency of said variable-frequency oscillator; means connecting the output terminal of said time delay-network to said voltage-control terminal to allow the output of said variable-voltage source to vary between predetermined levels thereby causing said variable-frequency source to generate said variable-frequency alarm signal; a first sound producer; means connecting said first sound producer to the output circuit of said variable-frequency oscillator to sound said warning signal and said alarm signal; a source of DC power; a transmission line including at least a first normally open detector switch for coupling said DC power source to said pair of terminals; and said warning signal being generated upon the closure of said detector switch, and said alarm signal being generated after a predetermined time interval from the time of closure of said detector switch as determined by said time-delay network.
Claim 2
Dependent Claim
236 words
A variable-tone electronic alarm system comprising: a pair of terminals; a variable-voltage source having a voltage control terminal; a variable-frequency oscillator having a frequency-control terminal, said oscillator producing a warning signal in the absence of a signal applied to said frequency-control terminal, and producing a variable-frequency alarm signal when a signal is applied to said frequency-control terminal; a time-delay network having an output terminal; means connecting said variable-voltage source, said variablefrequency oscillator, and said time-delay network in parallel circuit arrangement across said pair of terminals; means connecting the output of said variable-voltage source to said frequency-control terminal to control the frequency of said variable-frequency oscillator; means connecting the output terminal of said time delay-network to said voltage-control terminal to allow the output of said variable-voltage source to vary between predetermined levels thereby causing said variable-frequency source to generate said variable-frequency alarm signal; a first sound producer; means connecting said first sound producer to the output circuit of said variable-frequency oscillator to sound said warning signal and said alarm signal; a source of DC power; a transmission line including at least a first normally open detector switch for coupling said DC power source to said pair of terminals; and said warning signal being generated upon the closure of said detector switch, and said alarm signal being generated after a predetermined time interval from the time of closure of said detector switch as determined by said time-delay network.
Claim 3
Dependent Claim
56 words
The system of claim 1 and further including: a second sound producer; means including a pair of normally-open relay contacts for connecting said second sound producer in parallel-circuit relationship with said first sound producer; and a relay connected in the output circuit of said time-delay network for closing said relay contacts after said predetermined time interval.
Claim 4
Dependent Claim
36 words
The system of claim 2 and further including a power amplifier connected tO the output of said variable-frequency oscillator and to said first and second sound producers to amplify the signals generated by said variable-frequency oscillator.
Claim 5
Dependent Claim
13 words
The system of claim 3 wherein said warning signal has a single frequency.
Claim 6
Dependent Claim
13 words
The system of claim 4 wherein said alarm signal has a variable frequency.
Claim 7
Dependent Claim
19 words
The system of claim 5 wherein said first sound producer is positioned inside premises guarded by said alarm system.
Claim 8
Dependent Claim
16 words
The system of claim 6 wherein said second sound producer is positioned outside said guarded premises.
Claim 9
Dependent Claim
67 words
The system of claim 2 and further including: a second transmission line comprising at least a second normally open detector switch; and said second transmission line being connected between said DC power source and said voltage-control terminal thereby simultaneously energizing said relay and causing said variable-frequency oscillator to generate said variable-frequency alarm signal immediately after said second detector switch is closed in response to a monitored condition.
Claim 10
Dependent Claim
14 words
The system of claim 8 wherein, said second transmission line includes a silicon-controlled rectifier.
Claim 11
Dependent Claim
13 words
The system of claim 1 wherein, said transmission line includes a silicon-controlled rectifier.
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) | 1975-08-08 | 1976-02-07 | 1976-08-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-08 | 1980-02-07 | 1980-08-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-08 | 1984-02-07 | 1984-08-08 | $7700.00 | Window Closed / Lapsed |