Burglar alarm switch attached to door - comprises strip of material housing series of microswitches to be operated by pressure applied to door

摘要

The anti-burglar device for attached to a door comprises a series of microswitches which are closed if any attempt is made to force the door. The door frame has a groove around its edges in which the microswitch assembly is positioned. The assembly comprises two rigid plates extending along the full length of the strip, with the plate edges turned inwards. Blocks of foam material (13) hold the two rigid plates apart, and microswitches (10) are positioned near the blocks of foam to be actuated if the two rigid plates move together. A series of these strip assemblies fit around the door and are connected in parallel. The switches are connected to an external relay circuit which turns on an alarm if pressure is applied to the door in an attempt to break-in.