Patent US4550313A successfully refreshed from Google Patents.
US4550313A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fire detecting system
Assignee: Nittan Co Ltd
•
Filing: 1983-05-19
•
Granted: 1985-10-29
•
Expires: 2003-05-19
Abstract
Abstract A fire detecting system is disclosed, which comprises a sensor for producing an output voltage representing smoke level, heat, etc., and a comparator for producing a fire signal by comparing the output of the sensor or the differential or integral of the sensor output and a reference voltage. The sensor output or the differential or integral thereof is held in a peak hold circuit to be transferred through a switch to a sample-hold circuit for storage there.
Inventors
- 👤 Tetsuo Kimura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 20:34
CPC Classifications
G; G08; G08B; G08B17/00
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
109 words
A fire detecting systems comprising: a sensor which outputs a voltage corresponding to smoke concentration, temperature or the like; a comparator which compares the output voltage of the sensor with a reference voltage to produce a fire alarm when the output voltage of the sensor exceeds the reference voltage; a peak-hold circuit which holds a peak voltage of the output of the sensor; a sample-hold circuit which is capable of storing the output voltage of the peak-hold circuit to supply the stored voltage to the comparator as the reference voltage; a switch means which is capable of transferring the output voltage of the peak-hold circuit to the sample-hold circuit.
Claim 2
Dependent Claim
109 words
A fire detecting systems comprising: a sensor which outputs a voltage corresponding to smoke concentration, temperature or the like; a comparator which compares the output voltage of the sensor with a reference voltage to produce a fire alarm when the output voltage of the sensor exceeds the reference voltage; a peak-hold circuit which holds a peak voltage of the output of the sensor; a sample-hold circuit which is capable of storing the output voltage of the peak-hold circuit to supply the stored voltage to the comparator as the reference voltage; a switch means which is capable of transferring the output voltage of the peak-hold circuit to the sample-hold circuit.
Claim 3
Dependent Claim
119 words
A fire detecting system comprising: a sensor which outputs a voltage corresponding to smoke concentration, temperature of the like; a differentiator which differentiates the output voltage of the sensor; a comparator which compares the output voltage of the differentiator with a reference voltage to produce a fire alarm when the output voltage of the differentiator exceeds the reference voltage; a peak-hold circuit which holds a peak voltage of the output of the sensor; a sample-hold circuit which is capable of storing the output voltage of the peak-hold circuit to supply the stored voltage to the comparator as the reference voltage; a switch means which is capable of transferring the output voltage of the peak-hold circuit to the sample-hold circuit.
Claim 4
Dependent Claim
119 words
A fire detecting system comprising: a sensor which outputs a voltage corresponding to smoke concentration, temperature of the like; a differentiator which differentiates the output voltage of the sensor; a comparator which compares the output voltage of the differentiator with a reference voltage to produce a fire alarm when the output voltage of the differentiator exceeds the reference voltage; a peak-hold circuit which holds a peak voltage of the output of the sensor; a sample-hold circuit which is capable of storing the output voltage of the peak-hold circuit to supply the stored voltage to the comparator as the reference voltage; a switch means which is capable of transferring the output voltage of the peak-hold circuit to the sample-hold circuit.
Claim 5
Dependent Claim
119 words
A fire detecting system comprising: a sensor which outputs a voltage corresponding to smoke concentration, temperature or the like; an integrator which integrates the output voltage of the sensor; a comparator which compares the output voltage of the integrator with a reference voltage to produce a fire alarm when the output voltage of the integrator exceeds the reference voltage; a peak-hold circuit which holds a peak voltage of the output of the sensor; a sample-hold circuit which is capable of storing the output voltage of the peak-hold circuit to supply the stored voltage to the comparator as the reference voltage; a switch means which is capable of transferring the output voltage of the peak-hold circuit to the sample-hold circuit.
Claim 6
Dependent Claim
119 words
A fire detecting system comprising: a sensor which outputs a voltage corresponding to smoke concentration, temperature or the like; an integrator which integrates the output voltage of the sensor; a comparator which compares the output voltage of the integrator with a reference voltage to produce a fire alarm when the output voltage of the integrator exceeds the reference voltage; a peak-hold circuit which holds a peak voltage of the output of the sensor; a sample-hold circuit which is capable of storing the output voltage of the peak-hold circuit to supply the stored voltage to the comparator as the reference voltage; a switch means which is capable of transferring the output voltage of the peak-hold circuit to the sample-hold circuit.
Claim 7
Dependent Claim
22 words
A fire detecting system according to claim 1, 2 or 3, wherein the sensor produces an output voltage representing a heat level.
Claim 8
Dependent Claim
33 words
A fire detecting system according to claim 1, 2 or 3, wherein the switch is held open by a restoring force, is closed by merely pressing it, and is opened again when released.
References Cited (Backward Citations)
US4459583A
Cited
US4317113A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-10-28 | 1989-04-29 | 1989-10-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-10-28 | 1993-04-29 | 1993-10-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-10-28 | 1997-04-29 | 1997-10-29 | $7700.00 | Window Closed / Lapsed |