US3921074A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Safeguard sentry
Assignee: Individual
•
Filing: 1973-07-13
•
Granted: 1975-11-18
•
Expires: 1993-07-13
Abstract
Abstract A safeguard sentry for attachment to a radio or television receiving set comprises a receiver independent of the receiving set and responsive to a single predetermined emergency frequency. In one embodiment of the invention, the safeguard sentry is connected between the cut-off switch and the speaker of the receiving set, so that the safeguard sentry is energized when the receiving set is de-energized, and vice versa. In another embodiment of the invention, the safeguard sentry includes a switch which functions in one mode to couple speaker to the safeguard sentry, and in another mode to connect operating power to the receiving set, to couple the speaker of the receiving set to the safeguard sentry, and to activate a visual signaling device. In still another embodiment of the invention, the receipt of an emergency signal by the safeguard sentry activates circuitry which mutes the audio output of the receiving set and simultaneously connects the safeguard sentry to the speaker of the receiving set. Receipt of the emergency signal may also be used to actuate an internal emergency tone signal generator and/or a visual emergency signal apparatus. In all instances in which an audible signal is generated, the safeguard sentry of the present invention produces an output having at least a predetermined volume.
Inventors
- 👤 William C Baird
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 08:39
CPC Classifications
G; G08; G08B; G08B27/00; G08B27/008
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
179 words
Safeguard sentry circuitry which is continually energized to receive transmitted emergency information, comprising: a tunable receiving set having a speaker connected thereto for producing an audible output, said tunable receiving set being tunable to any desired carrier frequency within its tuning range for providing ordinary programming audio output at said speaker; an emergency signal receiver means independent of said tunable receiving set and being pretuned to a single predetermined emergency carrier frequency, said emergency signal receiver having radio-frequency and audio-frequency stages entirely distinct from those of said tunable receiving set for converting a received modulated emergency transmission at said predetermined carrier frequency into a corresponding audiofrequency output; and means for coupling said speaker of said tunable receiving set to the output of said emergency signal receiver means, said coupling means being operative to couple said speaker to the output of said emergency signal receiver means during the reception of any such audio frequency output irrespective of the frequency of the modulation of such emergency transmission signal and the corresponding frequency of such audio output of said emergency signal receiver.
Claim 2
Dependent Claim
179 words
Safeguard sentry circuitry which is continually energized to receive transmitted emergency information, comprising: a tunable receiving set having a speaker connected thereto for producing an audible output, said tunable receiving set being tunable to any desired carrier frequency within its tuning range for providing ordinary programming audio output at said speaker; an emergency signal receiver means independent of said tunable receiving set and being pretuned to a single predetermined emergency carrier frequency, said emergency signal receiver having radio-frequency and audio-frequency stages entirely distinct from those of said tunable receiving set for converting a received modulated emergency transmission at said predetermined carrier frequency into a corresponding audiofrequency output; and means for coupling said speaker of said tunable receiving set to the output of said emergency signal receiver means, said coupling means being operative to couple said speaker to the output of said emergency signal receiver means during the reception of any such audio frequency output irrespective of the frequency of the modulation of such emergency transmission signal and the corresponding frequency of such audio output of said emergency signal receiver.
Claim 3
Dependent Claim
43 words
The safeguard sentry circuitry of claim 1, further comprising manual switching means for alternatively energizing said emergency signal receiver means and said tunable receiving set such that said emergency signal receiver is energized whenever said tunable receiving set is deenergized and vice versa.
Claim 4
Dependent Claim
49 words
The safeguard sentry circuitry of claim 1, further comprising manual switching means associated with said emergency signal receiver means for selectively energizing said tunable set while simultaneously continuously providing energy to said emergency signal receiver such that said emergency signal receiver is energized independent of said tunable receiving set.
Claim 5
Dependent Claim
34 words
The safeguard sentry circuitry of claim 1, further comprising means for automatically muting the audio output of said tunable receiving set upon the reception of a modualted emergency transmission by said emergency signal receiver.
Claim 6
Dependent Claim
200 words
Safeguard sentry circuitry for producing an audible alarm signal upon receipt of a predetermined emergency frequency signal, comprising: a tunable receiving set having a speaker connected thereto for producing an audible output, said tunable receiving set being tunable to any desired carrier frequency within its tuning range for providing ordinary programming audio output at said speaker; an emergency signal receiver means independent of said receiving set and being pretuned to a single predetermined emergency carrier frequency, said emergency signal receiver havIng radio-frequency and audio-frequency stages entirely distinct from those of said tunable receiving set for converting a received modulated emergency transmission at said predetermined carrier frequency into a corresponding audio-frequency output of at least a predetermined amplitude; and means for coupling said speaker of said tunable receiving set to the output of said emergency signal receiver means to produce an audible alarm signal of at least a predetermined volume, said coupling means being operative to couple said speaker to the output of said emergency signal receiver means during the reception of any such audio frequency output irrespective of the frequency of modulation of such emergency transmission signal and the corresponding frequency of such audio output of said emergency signal receiver.
Claim 7
Dependent Claim
200 words
Safeguard sentry circuitry for producing an audible alarm signal upon receipt of a predetermined emergency frequency signal, comprising: a tunable receiving set having a speaker connected thereto for producing an audible output, said tunable receiving set being tunable to any desired carrier frequency within its tuning range for providing ordinary programming audio output at said speaker; an emergency signal receiver means independent of said receiving set and being pretuned to a single predetermined emergency carrier frequency, said emergency signal receiver havIng radio-frequency and audio-frequency stages entirely distinct from those of said tunable receiving set for converting a received modulated emergency transmission at said predetermined carrier frequency into a corresponding audio-frequency output of at least a predetermined amplitude; and means for coupling said speaker of said tunable receiving set to the output of said emergency signal receiver means to produce an audible alarm signal of at least a predetermined volume, said coupling means being operative to couple said speaker to the output of said emergency signal receiver means during the reception of any such audio frequency output irrespective of the frequency of modulation of such emergency transmission signal and the corresponding frequency of such audio output of said emergency signal receiver.
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) | 1978-11-17 | 1979-05-19 | 1979-11-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-17 | 1983-05-19 | 1983-11-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-17 | 1987-05-19 | 1987-11-18 | $7700.00 | Window Closed / Lapsed |