GB1406699A - Security alarm devices - Google Patents

Abstract

1406699 Mechanical switches NATIONAL PRESTO INDUSTRIES Inc 29 Dec 1972 [22 Nov 1972] 59975/72 Heading H1N [Also in Division G4] A switching arrangement for use in a burglar alarm attached to a door (see also Division G4) comprises an actuator rod 54 movable by member 18 from a position where it contacts a plunger 64 of a switch 40 (see Fig. 4) for closing the latter switch to a second position where a hook end of the rod is releasably held by one of catches 72, 86 (see Fig. 6) for keeping the switch 40 open. The catches 72, 86 are associated with a tripping lever 14 for releasing the actuator 54 and closing the switch 40 when the lever 14 senses that the door has been opened. Thus when member 18 is depressed with the door open, a latch member 74 having the catch 86 is in a forward position and rod 54 engages with catch 72; when the door is then closed, the latch 74 moves backwards and rod 54 under the resilience of a leaf spring 68 engages with catch 86. When the door is reopened, latch 74 moves forwards and rod 54 is released. Fig. 6 indicates that in the above positions, further switch contacts 124-126 are made and broken.