Patent GB-552081-A (GB)
Title: New or improved means for protection against fire and burglary
IPC: G08B19/00
Filed: 1941-09-17
Abstract: 552,081. Burglar and fire alarms. BOCK, W., and SLATTERY, E. R. Sept. 17, 1941, No. 11936. [Classes 40 (ii) and 118 (i)] [Also in Groups XL and XXI] A photo-electrically controlled Fire and Burglar alarm system comprises in combination a light-sensitive cell illuminated by the fire or by a lamp switched on by the proximity of a burglar, an electric relay operated when the light-sensitive cell is illuminated and serving to close an electric circuit, and a gramophone or sound-film apparatus adapted to be driven by a motor energized or released by the circuit closed by the aforesaid relay whereby to give a vocal alarm by one or more loudspeakers. Additional alarms may be given by lamps or other visible signals and by bells or other audible signals and fire-extinguishing devices may be set in operation at the same time. As shown in Fig. 1, a light-sensitive cell device 1 is provided near the ceiling of a room 2 to be influenced by light arising from any fire in the room ; and a light-sensitive cell device 3 in conjunction with a glow lamp 4 and a reflector 5 is provided on the door 43, the glowlamp being connected to one side of a mains circuit and on the other side to the lock 42, so that any increase in capacity between the lock and the earth due to a hand approaching or touching the lock causes the lamp 4 to glow. The circuit system is shown in Fig. 3 with both cell devices 1, 3 connected to the same relay circuits to avoid duplication of illustration. Actually, separate relay circuits are provided for each cell device. The cell device 1 contains a light-sensitive cell 34 connected in circuit with the moving coil 39 of a sensitive galvanometer 38 adapted to close a switch 36, 37 when the cell is illuminated. The cell device 3 comprises similar parts. The switch 36, 37 is in series with a relay coil 11, a switch 10, and a battery 9. The switch 10 is normally closed, so that when the switch 36, 37 closes, the coil 11 is energized and attracts its armature 59 which is pivoted at 58. A catch 56 on the other side of the pivot 58 then releases an adjustably weighted bell-crank lever 53, 50 which causes mechanically interconnected mercury switches 10, 13 to rock. The switch 10 breaks the circuit of battery 9 through relay 11, and the switch 13 closes a circuit 14 from the mains 15. The closing of the circuit 14 energizes the motor of a gramophone 16, lights up alarm lamps 31, and sets the fire-extinguishing devices 24, 26 in operation. The bell-crank lever 53, 50 has, in addition a cam 60 which closes a switch 28 setting an additional audible bell alarm 30 in operation. The cell device 3 is intended to operate a similar circuit system excluding the fire-extinguishing devices. The fire-extinguishing device 24 comprises a rose 61 with radiating pipes 62 terminating in nozzles 63 normally sealed bv a fusible material. The rose 61 is connected by flexible or jointed pipes 64, 66, 67 to a reservoir 68 of water or other fire-extinguishing liquid, and is normally held up against the ceiling by a cord 70 passing over pulleys 71, 72, 73 and attached to a counterweight guided in a cylinder 75, the counterweight is insufficient to hold the rose up and serves merely to slow down the fall of the rose when released bv a catch 76 by a coil 23 in the circuit 14 closed by the switch 13, when a fire occurs. The nozzle or nozzles 63 near the seat of the fire then become unsealed by the melting away of the fusible material, and the fluid flows out on the fire. The fusible seal may be replaced by valves opened by the relay circuits. The alternative or additional fire-extinguishing device 26 is made like a lamp standard or is embodied in a lamp standard or other piece of furniture and comprises a chamber 77 containing a glass bottle 78 adapted to be broken by a hammer 82 operated by a motor 25 set in action by the closing of the circuit 14 by the switch 13. The chamber 77 contains a fire-extinguishing material or substances producing a fire-extinguishing material when mixed with the contents of the bottle 78, and this mixture also produces internal gaseous pressure to drive the fire-extinguishing material out of nozzles 80 similar to the nozzles 63.