Patent US4577544A successfully refreshed from Google Patents.
US4577544A
Expired / Lapsed
US
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Ultrafast thermal actuator
Assignee: Zeneca Inc
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Filing: 1984-05-14
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Granted: 1986-03-25
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Expires: 2004-05-14
Abstract
Abstract Fast acting actuation system which is especially suitable for automatic sprinklers and other emergency devices. The system includes a fast-acting low mass thermally responsive element comprising a pair of thin metal strips soldered together, a percussion member such as a firing pin which is released when the solder in the thermally responsive element melts, and an actuator, preferably a radially expandable explosive actuator, which is initiated by the firing pin. The actuator when initiated causes rapid actuation of the automatic sprinkler or other device.
Inventors
- 👤 John T. M. Lee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 21:47
CPC Classifications
A; A62; A62C; A62C37/00; A62C37/08; A62C37/10; A62C37/11; A62C37/12; F; F42; F42C; F42C15/00; F42C15/36; F42C9/00; F42C9/08
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
72 words
An actuation system comprising: (a) a percussion-initiated radially expandable actuator having a percussion-initiated explosive input charge, an explosive output charge and a casing, at least a portion of which expands radially outwardly when sid output charge is fired; (b) a normally retracted percussion member which when released initiates said actuator; and (c) a thermally responsive fusible link having a thin layer of fusible material for controlling the release of said percussion member.
Claim 2
Dependent Claim
72 words
An actuation system comprising: (a) a percussion-initiated radially expandable actuator having a percussion-initiated explosive input charge, an explosive output charge and a casing, at least a portion of which expands radially outwardly when sid output charge is fired; (b) a normally retracted percussion member which when released initiates said actuator; and (c) a thermally responsive fusible link having a thin layer of fusible material for controlling the release of said percussion member.
Claim 3
Dependent Claim
30 words
An actuation system according to claim 1 wherein said input charge is encased in a ductile thin-walled tubular casing, said tubular casing providing a striking surface for the percussion member.
Claim 4
Dependent Claim
44 words
An actuation system of claim 1 in which said thermally responsive fusible link consists essentially of overlapping thin strips held together by a thin layer of fusible material to form a lap joint having a surface-to-volume ratio of at least 100 inch -1 .
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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) | 1989-03-24 | 1989-09-23 | 1990-03-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-03-24 | 1993-09-23 | 1994-03-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-03-24 | 1997-09-23 | 1998-03-25 | $7700.00 | Window Closed / Lapsed |