Patent US4771270A successfully refreshed from Google Patents.
US4771270A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Temperature sensitive fire alarm unit
Assignee: Individual
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Filing: 1987-04-23
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Granted: 1988-09-13
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Expires: 2007-04-23
Abstract
Abstract A simple, compact and inexpensive battery powered fire alarm unit has a normally closed spring-loaded electrical contact which is held open by a cermet metal strip, or the like, which is constructed to melt and fail at a predetermined high temperature level indicative of a fire condition. When the strip fails, the contact closes and connects an electrically activated sounder across the battery.
Inventors
- 👤 James W. Kelso
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 20:07
CPC Classifications
G; G08; G08B; G08B17/00; G08B17/06
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
125 words
A temperature sensitive fire alarm unit comprising: a case; a battery mounted in said case; an electrical contact pivotally mounted within said case and positioned selectively to engage one terminal of said battery; an electrically energized alarm transducer mounted in said case and electrically connected to a second terminal of said battery and to said contact to be activated when said contact engages said one terminal of said battery; resilient means mounted in said case and physically connected to said contact for biasing said contact into engagement with said battery; and a temperature sensitive element physically connected to said contact to hold said contact displaced from said battery until the ambient temperature exceeds a predetermined threshold at which said temperature sensitive element melts and fails.
Claim 2
Dependent Claim
125 words
A temperature sensitive fire alarm unit comprising: a case; a battery mounted in said case; an electrical contact pivotally mounted within said case and positioned selectively to engage one terminal of said battery; an electrically energized alarm transducer mounted in said case and electrically connected to a second terminal of said battery and to said contact to be activated when said contact engages said one terminal of said battery; resilient means mounted in said case and physically connected to said contact for biasing said contact into engagement with said battery; and a temperature sensitive element physically connected to said contact to hold said contact displaced from said battery until the ambient temperature exceeds a predetermined threshold at which said temperature sensitive element melts and fails.
Claim 3
Dependent Claim
24 words
The temperature sensitive fire alarm unit defined in claim 1, in which said temperature sensitive element is formed of a selected cermet metal material.
References Cited (Backward Citations)
US2710393A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-09-13 | 1992-03-14 | 1992-09-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-09-13 | 1996-03-14 | 1996-09-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-09-13 | 2000-03-14 | 2000-09-13 | $7700.00 | Window Closed / Lapsed |