US3887815A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photoelectric smoke detector
Assignee: Hochiki Corp
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Filing: 1973-12-10
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Granted: 1975-06-03
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Expires: 1993-12-10
Abstract
Abstract A photoelectric smoke detector comprising a source of light intermittently energized to flash by the output of a first oscillator, and a light receiving circuit energized and operated intermittently by the output of a second oscillator, wherein the oscillation periods of the first and second oscillators are different from each other, and the outputs of the first and second oscillators are applied to the light source through an AND gate, whereby the light receiving circuit is brought into operation when a light is emitted from the light source.
Inventors
- 👤 Mamoru Kawakami
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 07:04
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/47; G01N21/49; G01N21/53; G08; G08B; G08B17/00; G08B17/10; G08B17/103; G08B17/107
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
106 words
A photoelectric smoke detector comprising a source of light, a first oscillator connected to said source, said source being adapted for being intermittently energized by the output of said first oscillator, a second oscillator, a light receiving circuit including a photoelectric means adapted for being energized by the output of a second oscillator thereby to come into operation intermittently for receiving light scattered by smoke generated by the source of light, the first and second oscillators having different oscillation periods, and an AND gate circuit controlled by the outputs of the first and second oscillators being connected between the first oscillator and the source of light.
Claim 2
Dependent Claim
106 words
A photoelectric smoke detector comprising a source of light, a first oscillator connected to said source, said source being adapted for being intermittently energized by the output of said first oscillator, a second oscillator, a light receiving circuit including a photoelectric means adapted for being energized by the output of a second oscillator thereby to come into operation intermittently for receiving light scattered by smoke generated by the source of light, the first and second oscillators having different oscillation periods, and an AND gate circuit controlled by the outputs of the first and second oscillators being connected between the first oscillator and the source of light.
Claim 3
Dependent Claim
106 words
A photoelectric smoke detector comprising a source of light, a first oscillator connected to said source, said source being adapted for being intermittently energized by the output of said first oscillator, a second oscillator, a light receiving circuit including a photoelectric means adapted for being energized by the output of a second oscillator thereby to come into operation intermittently for receiving light scattered by smoke generated by the source of light, the first and second oscillators having different oscillation periods, and an AND gate circuit controlled by the outputs of the first and second oscillators being connected between the first oscillator and the source of light.
Claim 4
Dependent Claim
106 words
A photoelectric smoke detector comprising a source of light, a first oscillator connected to said source, said source being adapted for being intermittently energized by the output of said first oscillator, a second oscillator, a light receiving circuit including a photoelectric means adapted for being energized by the output of a second oscillator thereby to come into operation intermittently for receiving light scattered by smoke generated by the source of light, the first and second oscillators having different oscillation periods, and an AND gate circuit controlled by the outputs of the first and second oscillators being connected between the first oscillator and the source of light.
Claim 5
Dependent Claim
26 words
A photoelectric smoke detector according to claim 1, wherein the oscillation period of the first oscIllator is shorter than the oscillation period of the second oscillator.
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) | 1978-06-02 | 1978-12-02 | 1979-06-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-02 | 1982-12-02 | 1983-06-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-02 | 1986-12-02 | 1987-06-03 | $7700.00 | Window Closed / Lapsed |