GB1236902A - Alarm device - Google Patents

Abstract

1,236,902. Locks. GENERAL ALARM CORP. 14 Jan., 1969 [25 Jan., 1968], No. 2057/69. Heading E2A. [Also in Division G4] An alarm device for a closure member and a member to which the closure member can be fastened in its closed position, comprises an anchor plate 28 for securing to one member, a top plate 30 secured to the anchor plate for relative movement therebetween, and against spring means 60, electrical alarm means 86, 87, a multi-position switch 90 for actuating the alarm means 86, 87 and having spaced apart contacts series connected to the alarm means, and a plunger rod 40 completing a circuit between the contacts when in a first position and maintaining an open circuit when in a second position, resilient means 41 biassing the rod to the first position and latch means 54, 92 for holding the rod in the second position and being releasable upon relative movement of the top plate 30 and the anchor plate 28. As shown, the device is mounted on a top rail 21 of a lower sash 22 adjacent to a side member 24 of an upper sash 26 and comprises a cover 39. An inner member 38 of the top plate 30 is formed with recesses 70, 72 for batteries 74, and is provided with a pair of switch contacts 90, a cavity 85 for an alarm generator 86 and with an alarm device 87. The plunger rod 40 is housed in a bore 80 and is normally biassed by the spring 41 so that a tab 92 is held by a catch 54 on a blade spring 56 in the anchor plate 28 to maintain the alarm device inoperative. The cover 39 is secured to the anchor plate by means of a screw 116 and by a pair of flanges 105 which resiliently engage under a spring fixed to the anchor plate. The cover is formed with a bore for a plug 34 carrying a locking bolt 100 which is engageable in a recess 120 in the sash 26. In use any prying or jimmying force between the sashes, moves the cover 39 and inner member 38 against the spring 60 and releases the tab from the catch 54 causing the rod 40 to move into a recess 112 in the plug 34 and completes an electrical circuit through the switch contacts to the alarm generator 86. When the plug 34 is unlocked to retract the bolt 100, the outer end of the rod 40 rides up a ramp 114 of the recess 112 and is thereby reset to the non-operated condition of the alarm. In another embodiment, Figs. 10-12 (not shown) the device is applied to a door and the lock bolt co-operates with a keeper on the door frame.