Patent US3735150A successfully refreshed from Google Patents.
Patent US3175206A successfully refreshed from Google Patents.
US3175206A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fire detector with integrity-testing device
Assignee: Lindberg AS
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Filing: 1964-07-14
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Granted: 1965-03-23
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Expires: 1984-07-14
Abstract
No abstract record available.
Inventors
- 👤 Jr John E Lindberg
- 👤 Stephen A Miller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 08:13
CPC Classifications
G; G08; G08B; G08B29/00; G08B29/12; G08B29/14; G08B29/145
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
146 words
A FIRE DETECTION SYSTEM COMPRISING A HEAT SENSOR HAVING TWO ELECTRICAL CONDUCTORS SPACED APART BY A HEAT SENSITIVE MATERIAL WHICH IS OF LOW ELECTRICAL CONDUCTIVITY BELOW A CRITICAL TEMPERATURE AND IS MORE ELECTRIALLY CONDUCTIVE ABOVE SAID CRITICAL TEMPERATURE, SAID HEAT SENSOR BEING CONNECTED IN A COMPARATOR CIRCUIT WITH A FIRST SOURCE OF ELECTRICAL POTENTIAL AND A WARNING DEVICE, HEATING OF SAID HEAT SENSITIVE MATERIAL BY A FIRE CAUSING THE RESISTANCE THEREOF TO BE LOWERED SO THAT AN UNBALANCE POTENTIAL IS PRODUCED BY SAID COMPARATOR CIRCUIT TO ACTUATE SAID WARNING DEVICE, A SECOND SOURCE OF ELECTRICAL POTENTIAL, AND MEANS FOR TEMPORARILY CONNECTING THE TWO ENDS OF ONE OF SAID CONDUCTORS TO SAID SECOND SOURCE OF POTENTIAL TO HEAT SAID ONE CONDUCTOR AND THEREBY HEAT SAID HEAT-SENSITIVE MATERIAL ABOVE SAID CRITICAL TEMPERATURE TO CAUSE SAID WARNING DEVICE TO BE ACTUATED SO THAT THE WHOLE SYSTEM IS THEREBY TESTED.
Claim 2
Dependent Claim
146 words
A FIRE DETECTION SYSTEM COMPRISING A HEAT SENSOR HAVING TWO ELECTRICAL CONDUCTORS SPACED APART BY A HEAT SENSITIVE MATERIAL WHICH IS OF LOW ELECTRICAL CONDUCTIVITY BELOW A CRITICAL TEMPERATURE AND IS MORE ELECTRIALLY CONDUCTIVE ABOVE SAID CRITICAL TEMPERATURE, SAID HEAT SENSOR BEING CONNECTED IN A COMPARATOR CIRCUIT WITH A FIRST SOURCE OF ELECTRICAL POTENTIAL AND A WARNING DEVICE, HEATING OF SAID HEAT SENSITIVE MATERIAL BY A FIRE CAUSING THE RESISTANCE THEREOF TO BE LOWERED SO THAT AN UNBALANCE POTENTIAL IS PRODUCED BY SAID COMPARATOR CIRCUIT TO ACTUATE SAID WARNING DEVICE, A SECOND SOURCE OF ELECTRICAL POTENTIAL, AND MEANS FOR TEMPORARILY CONNECTING THE TWO ENDS OF ONE OF SAID CONDUCTORS TO SAID SECOND SOURCE OF POTENTIAL TO HEAT SAID ONE CONDUCTOR AND THEREBY HEAT SAID HEAT-SENSITIVE MATERIAL ABOVE SAID CRITICAL TEMPERATURE TO CAUSE SAID WARNING DEVICE TO BE ACTUATED SO THAT THE WHOLE SYSTEM IS THEREBY TESTED.
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) | 1968-03-22 | 1968-09-21 | 1969-03-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1972-03-22 | 1972-09-21 | 1973-03-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1976-03-22 | 1976-09-21 | 1977-03-23 | $7700.00 | Window Closed / Lapsed |