GB589160A - Improvements in or relating to automatic alarm systems - Google Patents

Abstract

589,160. Automatic exchange systems. PICKING. A. S. H., and ROONEY, I. H. March 15, 1945, No. 6590. [Class 40 (iv)] In an automatic alarm system of the kind used with a dial telephone for dialling a predetermined number, e.g. a police or fire station, and sending a warning signal to the called party, a rotating switch device is set in operation by an alarm signal (from a source not shown) and controls a solenoid 16 which when energized causes a member 18 to engage a finger hole in the dial 23, the switch then rotating it to carry out dialling operations. The lever 32, normally under the control of abutment 31 on the carriage 30, engages the switch-hook 26 of the telephone 24. An initiating alarm starts the electric motor 7 which rotates the shaft 6 ; the member 41 rides on a snail cam and reciprocates vertically, thus stepping the carriage 30 to the left. The spring 60 then swings the lever 32 to operate the switch 26. The wiper 46 is brought into contact with the discs 47 in turn, each of which has a conducting segment, and the solenoid 16 is energized during the period of contact of this segment with the wiper 46 to couple the shaft 6 to the dial. These periods are such that each disc control the dialling of a predetermined digit, provision being made for up to seven digits. On completion of the dialling, the wiper steps on to discs 52 which operate a sound producer (Fig. 2, not shown), such as a bell or buzzer disposed near the microphone, to signal to the called party. Alternatively, an audible message may be given phonographically. The apparatus is then reset to the rest position and the call is repeated until the motor is switched off. The Provisional Specification describes means for stopping the apparatus after completion of one call, and also for moving the lever 32, independently of the shaft 6, by electromagnetic means controlled by the alarm.