Fire alarm system
First Claim
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1. A fire alarm system comprising fire detectors for detecting a physical change caused by fire and a central signal station connected to the fire detectors so as to receive a first signal from the detectors to raise an alarm, said central signal station and said fire detectors being connected to each other through optical fiber cables;
- said central signal station including a light source for transmitting power light superposed with timing signals to said detectors through said optical fiber cables, a fire signal detecting circuit for detecting a fire signal by converting a fire signal light transmitted from a detector through said optical fiber cables into an electric signal, an alarm indicating circuit to be operated by the fire signal for giving the alarm of fire and a d.c. power source for supplying power to the light source and the circuits in the central signal station;
said light source of the central signal station including a plurality of light emitting circuits for emitting power light via respective optical fiber cables to respective detectors, and a timing circuit for sequentially outputting timing signals for the respective light emitting circuits so as to superpose the timing signals on the power light;
said fire detectors each including a power source section comprised of a photoelectric converter for converting said power light into electricity, a booster circuit for boosting the output from said photoelectric converter and a back-up battery, a fire detecting section for detecting a physical change caused by fire and outputting a fire signal, a fire signal transmitting section for converting said fire signal into fire signal light and transmitting said fire signal light to the central signal station and a timing control section for detecting said timing signals and controlling the operation timing of said fire detecting section and said first signal light transmitting section;
said timing control section of each of the detectors including a timing signal detecting circuit and a gate circuit inserted and connected in a power line connected between said back-up battery and said signal light transmitting section and opened or closed in response to the detected timing signal to connect or disconnect the power supply to the succeeding circuits for controlling the operation timing thereof.
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Accused Products
Abstract
A plurality of fire detectors for detecting a physical change caused by fire and a central signal station for receiving a fire signal from the fire detectors to raise an alarm are connected to each other through optical fiber cables. The central signal station transmits power light for supplying power and timing signals which are superposed on the power light for controlling operation timing to the respective detectors through the optical fiber cables, while each of the fire detectors converts the power light into electric power, carries out a fire detecting operation in response to the timing signals and transmits, upon detection of a fire, a fire signal in the form of light to the central signal station through the optical fiber cable.
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Citations
11 Claims
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1. A fire alarm system comprising fire detectors for detecting a physical change caused by fire and a central signal station connected to the fire detectors so as to receive a first signal from the detectors to raise an alarm, said central signal station and said fire detectors being connected to each other through optical fiber cables;
- said central signal station including a light source for transmitting power light superposed with timing signals to said detectors through said optical fiber cables, a fire signal detecting circuit for detecting a fire signal by converting a fire signal light transmitted from a detector through said optical fiber cables into an electric signal, an alarm indicating circuit to be operated by the fire signal for giving the alarm of fire and a d.c. power source for supplying power to the light source and the circuits in the central signal station;
said light source of the central signal station including a plurality of light emitting circuits for emitting power light via respective optical fiber cables to respective detectors, and a timing circuit for sequentially outputting timing signals for the respective light emitting circuits so as to superpose the timing signals on the power light;
said fire detectors each including a power source section comprised of a photoelectric converter for converting said power light into electricity, a booster circuit for boosting the output from said photoelectric converter and a back-up battery, a fire detecting section for detecting a physical change caused by fire and outputting a fire signal, a fire signal transmitting section for converting said fire signal into fire signal light and transmitting said fire signal light to the central signal station and a timing control section for detecting said timing signals and controlling the operation timing of said fire detecting section and said first signal light transmitting section;
said timing control section of each of the detectors including a timing signal detecting circuit and a gate circuit inserted and connected in a power line connected between said back-up battery and said signal light transmitting section and opened or closed in response to the detected timing signal to connect or disconnect the power supply to the succeeding circuits for controlling the operation timing thereof. - View Dependent Claims (2, 3, 4, 9, 10, 11)
- said central signal station including a light source for transmitting power light superposed with timing signals to said detectors through said optical fiber cables, a fire signal detecting circuit for detecting a fire signal by converting a fire signal light transmitted from a detector through said optical fiber cables into an electric signal, an alarm indicating circuit to be operated by the fire signal for giving the alarm of fire and a d.c. power source for supplying power to the light source and the circuits in the central signal station;
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5. A fire alarm system comprising fire detectors for detecting a physical change caused by fire and a central signal station connected to the fire detectors so as to receive a fire signal from the detectors to raise an alarm, said fire detectors being connected, through optical couplers, to a common optical fiber cable which is in turn connected to the central signal station;
- said central signal station including a light source for transmitting power light superposed with timing signals to said detectors through the optical fiber cable, a fire signal detecting circuit for detecting a fire signal by converting a fire signal light transmitted from a detector through said optical fiber cable into an electric signal, an alarm indicating circuit to be operated by the fire signal for giving the alarm of fire and a d.c. power source for supplying power to the light source and the circuits in the central signal station;
said light source of the central signal station including a light emitting circuit for emitting power light to the detectors and a timing circuit for outputting, to the light emitting circuit, timing signals including a series of operation timing signals for the respective detectors and a signal indicating the starting point of the operation timing signals;
said central signal station including a detector identifying circuit for identifying by said timing signals the fire detector which has generated a fire signal;
said fire detectors each including a power source section comprised of a photoelectric converter and a back-up battery, a fire detecting section for detecting a physical change caused by fire and outputting a fire signal, a fire signal transmitting section for converting said fire signal into fire signal light and transmitting said fire signal light to the central signal station and a timing control section for detecting said timing signals and controlling the operation timing of said fire detecting section and said fire signal light transmitting section, said timing control section of each of the detectors incluidng a timing signal detecting circuit comprised of a circuit for detecting the operation timing signal, a circuit for detecting the signal indicating the starting point of the series of the operation timing signals and a circuit adapted to be reset by the signal indicating the starting point of the series of operation timing signals and extract a timing signal allotted to the relevant detector from said series of operation timing signals, and a gate circuit inserted and connected in a power line which is connected between said back-up battery and said signal light transmitting section to be opened or closed in response to the detected timing signal and connect or disconnect the power supply to the succeeding circuits for controlling the operation timing thereof. - View Dependent Claims (6, 7, 8)
- said central signal station including a light source for transmitting power light superposed with timing signals to said detectors through the optical fiber cable, a fire signal detecting circuit for detecting a fire signal by converting a fire signal light transmitted from a detector through said optical fiber cable into an electric signal, an alarm indicating circuit to be operated by the fire signal for giving the alarm of fire and a d.c. power source for supplying power to the light source and the circuits in the central signal station;
Specification
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Current AssigneeHochiki Kabushiki Kaisha
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Original AssigneeHochiki Kabushiki Kaisha
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InventorsMiyabe, Atsushi
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Primary Examiner(s)Swann, III, Glen R.
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Application NumberUS06/493,246Time in Patent Office602 DaysField of Search340/584, 340/628, 340/629, 340/630, 340/531, 340/518, 340/870.28, 340/870.29US Class Current340/584CPC Class CodesG08B 17/00 Fire alarms; Alarms respons...G08B 17/10 Actuation by presence of sm...G08B 17/113 Constructional detailsH04B 10/807 Optical power feeding, i.e....
