GB509846A - Improvements in or relating to fire alarm systems or the like - Google Patents

Abstract

509,846. Fire-alarm systems. AUTOMATIC TELEPHONE & ELECTRIC CO., Ltd., and BROWN, W. J. Jan. 22, 1938, No. 2196. [Class 40 (i)] In a fire-alarm or like system arranged for markings characteristic of a calling point to be recorded on a moving tape, an indication of the time which elapses before a particular action such as the fire engine turnout takes place in response to a call, is recorded on the same tape. Impulses received from a calling point by the fire alarm equipment are repeated to operate slow-to-release relay G, which remains operated throughout the receipt of the code, causing relay B to operate to prepare a circuit for relay S, completed every second, for half a second, when contacts 13 close under the control of a clock. Upon S operating, driving magnet DM is energised and relay A operated, S releasing, when contacts 13 open, causing the step-by-step switch associated with magnet DM to step rotating a type wheel which prints on a moving tape when the magnet PSM is entergised during the release period of A. When the engine leaves the station, contacts 14 are momentarily closed, and, if the code is still being received so that G is still operated, slow-to-operate relay C operates and locks up, magnet EPM printing an indication on the tape that the engine has left. At the termination of the code, G, B, and C release in turn, completing a homing circuit for driving magnet DM including relay X which prevents the reception of a. further call until this operation is completed. If the code terminated before contacts 14 closed, G will have been released, B remaining operated so that the driving magnet will have stepped on the type wheel without, however, the printing magnet PSM being energised. Upon the contacts 14 closing, C will operate, releasing B, in turn releasing C, as above, and causing the type wheel to print and the apparatus to return to normal. Fault indication. If contacts 14 should remain closer, a delayed alarm circuit is completed over line 12, while if they fail to close, a relay, (not shown), locked up when the call was received and normally released upon relay C operating, brings in a delayed alarm.