Fire alarm apparatus
Number of patents in Portfolio can not be more than 2000
United States of America Patent
Stats
-
Jul 5, 1988
Grant Date -
N/A
app pub date -
Jun 11, 1987
filing date -
Aug 14, 1986
priority date (Note) -
Expired
status (Latency Note)
Importance
Abstract
A fire alarm apparatus includes a fire receiver, a pair of transmission lines extending from the fire receiver, a series of nonpolar fire detectors connected to the transmission lines, and a terminating unit, connected to the end terminals of the transmission lines, the terminating unit having an impedance element including a polar element. Each fire detector includes polarity inverting circuitry which includes a limit switch, arranged at a socket portion of the detector, and having a switch lever which is actuated by the detector body engaging with the socket portion; and diodes for inverting the polarity of the pair of transmission lines in synchronism with actuation of the switch lever. The polarity of the transmission lines after a detector is inverted when a detector body is detached from that detector.
First Claim
Family
International Classification(s)
Cited Art Landscape
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