GB720507A - Improvements in or relating to means for detecting unauthorised entry into, or removal of articles from, enclosed spaces - Google Patents

Abstract

720,507. Switches held set and freed mechanically; actuation of switches. TOMKINS, C. L. Sept. 2, 1953 [June 4, 1952], No. 14061/52. Class 38 (5) [Also in Group XXXVIII] An arrangement for affording protection for articles contained within an enclosed space such as a room, large container or van, comprises a plurality of tubes 10, Fig. 4, extending along or close to the walls of the enclosed space, with a wire 11 maintained under tension extending through each tube, and a plurality of electric switches (each comprising an arm 19, tension spring 23 and contact 25) attached one at each end of each wire 11. The switches are connected in parallel in an electric circuit supplied from a source 28 through the wires 26 (see also Fig. 2) which pass through holes in each of the contact members 25 and are connected to the supply leads 29 through the horizontal spring-loaded arms 27 of further switches. The arms 19 and 27 of the switches are normally insulated from the casing, insulating nuts 21 and bushes 22 being used to secure the arms pivotally to the casing. Similarly, insulating collars 24 are used to insulate the springs 23 from the casing. Upon any interference causing displacement of a wire or an alteration of the tension therein, one of the arms 19, 27 makes electrical contact with the casing thereby operating an alarm.