Fire detector and fire alarm system having circuitry to detect removal of one or more detectors at a signal station
First Claim
1. A fire detector comprised of a detector head and a socket, said socket being connected across a pair of lines leading to a signal station and serially connecting, through said detector head, one of said pair of lines to a succeeding fire detector formed and connected identically with said fire detector, which detector is characterized by a means for disconnecting said one line from said signal station temporarily when said detector head is being removed from said socket.
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Accused Products
Abstract
A fire detector and a fire alarm system wherein a plurality of fire detectors are connected across a pair of lines leading to a signal station and which is capable of detecting, at the signal station, removal of a detector head or heads from an associated socket or sockets of any one or more detectors and yet capable of keeping the succeeding fire detectors operative to send a possible fire alarm signal even after removal of the head or heads. Each of said fire detectors comprises a means for disconnecting the line connected therethrough to the succeeding detector, temporarily in the course of removal of the detector head or heads from the associated socket or sockets or periodically after the detector or detectors has or have been removed from the associated socket or sockets. The signal station comprises a means for detecting the temporary or periodical disconnection of the line.
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Citations
20 Claims
- 1. A fire detector comprised of a detector head and a socket, said socket being connected across a pair of lines leading to a signal station and serially connecting, through said detector head, one of said pair of lines to a succeeding fire detector formed and connected identically with said fire detector, which detector is characterized by a means for disconnecting said one line from said signal station temporarily when said detector head is being removed from said socket.
- 13. A fire alarm system wherein a plurality of fire detectors each comprised of a detector head and a socket are sequentially connected in parallel to a pair of lines leading to a signal station, a terminating element is provided at the end of the lines to form a closed loop of the lines and one of said lines is connected through the respective fire detectors to the respectively succeeding detectors, which system is characterized in that each of said fire detectors includes a means for disconnecting the line connected therethrough to the succeeding detector temporarily during removal of said detector head from said socket and said signal station includes a means for detecting the temporary disconnection of the line by said fire detector.
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18. A fire detector comprised of a detector head and a socket, said socket being connected across a pair of lines leading to a signal station and serially connecting, through said detector head, one of said pair of lines to a succeeding fire detector formed and connected identically with said fire detector, which detector is characterized by a means for disconnecting said one line from said signal station periodically after said detector head has been removed from said socket.
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19. A fire alarm system wherein a plurality of fire detectors each comprised of a detector head and a socket are sequentially connected in parallel to a pair of lines leading to a signal station, a terminating element is provided at the end of the lines to form a closed loop of the lines and one of said lines is connected through the respective fire detectors to the respectively succeeding detectors, which system is characterized in that each of said fire detectors includes a means for disconnecting the line connected therethrough to the succeeding detector periodically after said detector head has been removed from said socket and said signal station includes a means for detecting the periodical disconnection of the line by said fire detector.
Specification