US4975684A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fire detecting system
Assignee: Cerberus AG
•
Filing: 1989-06-09
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Granted: 1990-12-04
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Expires: 2009-06-09
Abstract
Abstract A fire detector having a first sensor for emitting a first output signal in response to a fire phenomenon, a second sensor for detecting a source of false alarm conditions generated by man and/or machinery and an evaluating circuit. The evaluating circuit has a mechanism for activating an alarm signal when the value of the output of the first sensor exceeds a threshold value. The threshold value is set by the second sensor in response to the detection of signals generated during normal use of the premises to be protected.
Inventors
- 👤 Hannes Guttinger
- 👤 Mark Jaggi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 07:55
CPC Classifications
G; G08; G08B; G08B17/00
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
117 words
A fire detector for protecting premises periodically occupied by workers and operating machinery, said fire detector comprising: at least one first sensor for emitting a first output signal in response to a fire phenomenon, at least one second sensor for detecting a source of false alarm conditions, said false alarm conditions being detected from the presence and activities of said workers and operating machinery and an evaluating circuit, said evaluating circuit comprising means for providing an alarm signal in response to a value of said first output signal exceeding a threshold value and means for changing said threshold value relative to said first output signal value in response to a second output signal from said second sensor.
Claim 2
Dependent Claim
117 words
A fire detector for protecting premises periodically occupied by workers and operating machinery, said fire detector comprising: at least one first sensor for emitting a first output signal in response to a fire phenomenon, at least one second sensor for detecting a source of false alarm conditions, said false alarm conditions being detected from the presence and activities of said workers and operating machinery and an evaluating circuit, said evaluating circuit comprising means for providing an alarm signal in response to a value of said first output signal exceeding a threshold value and means for changing said threshold value relative to said first output signal value in response to a second output signal from said second sensor.
Claim 3
Dependent Claim
23 words
A fire detector according to claim 1, wherein the first sensor is selected from the group consisting of ionization-type sensors and optical-type sensors.
Claim 4
Dependent Claim
23 words
A fire detector according to claim 1, wherein the second sensor is selected from the group consisting of acoustic, infrared and motion sensors.
Claim 5
Dependent Claim
27 words
A fire detector according to claims 2 or 3 wherein the first sensor is an ionization type sensor and the second sensor is an acoustical type sensor.
Claim 6
Dependent Claim
17 words
A fire detector according to claim 2 wherein the first sensor is a diffused light smoke sensor.
Claim 7
Dependent Claim
17 words
A fire detector according to claim 1 wherein the evaluating circuit is integrated with the first sensor.
Claim 8
Dependent Claim
20 words
A fire detector according to claim 1 wherein the evaluating circuit is integrated with fire detection control and indicating equipment.
Claim 9
Dependent Claim
17 words
A fire detector according to claim 1 wherein the second sensor is integrated with the first sensor.
Claim 10
Dependent Claim
21 words
A fire detector according to claim 1 wherein the threshold value is changed by a switch means in the evaluating circuit.
Claim 11
Dependent Claim
39 words
A fire detector according to claim 9 wherein the means for providing an alarm signal comprises a threshold detector and the switch means changes the threshold detector value in response to said second output signal of said second sensor.
Claim 12
Dependent Claim
24 words
A fire detector according to claim 9 wherein the switch means changes the value of said first output signal relative to said threshold value.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-12-03 | 1994-06-04 | 1994-12-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-12-03 | 1998-06-04 | 1998-12-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-12-03 | 2002-06-04 | 2002-12-04 | $7700.00 | Window Closed / Lapsed |