Burglar alarm activator mounted in door lock - using magnetically operated reed relay and contactors which detect if lock is dislodged

摘要

The burglar alarm activating switch is for mounting in a door lock mechanism which depends on a magnetically operated reed relay contact in contrast to the more dust prone microswitch operated devices. basically, a reed relay contact pair (13) is mounted within the lock mechanism mounted on the door post (7) and this is activated by a magnet (14) from which the reed relay is normally shielded by a small spring mounted (15) metal plate (16) during normal operation of the key (14) in the lock (1) on the door (2). An additional contact pair (21, 22) is also mounted within the mechanism, and these separate if the door is forced in such a way that the lock mechanism (11) is dislodged from its mounting (10).