Electrically operated door security alarm switch - is actuated by plate held by four compression springs and forms electrical contact with alarm system when springs are compressed

摘要

The switch has an overall cover secured with the mechanism and base plate to the door frame by two screws. The chassis consists of a panel folded to form a rectangular channel either side of a wide central chennel opening in the opposite direction. The two side channels each have a plate closing their open side, secured by a pair of bolts, through the channel bases compression springs coaxial to the bolts holding the chassis in position. Opening the door compresses the springs and operates a switch housed on either of the channels. The chassis is U-shaped and the channels are formed by having the two ends of the 'U' folded over at right angles twice in succession.