GB1502389A - Cylinder lock arrangement with alarm device - Google Patents

Abstract

1502389 Alarm-equipped locks W WINKHAUS and H WINKHAUS [trading as AUG WINKHAUS] 11 Dec 1975 [11 Dec 1974] 50850/75 Heading E2A A locking mechanism comprising a cylinder lock and a rim lock, the bolt of which is moved by means connected to the cylinder lock, is equipped with an alarm which is actuated by an electric circuit which is completed when attempts are made to open the door by means other than the use of the proper key. In Fig. 9, device 148 carrying a contact 154 is mounted by a pivot 150 on the cylinder lock casing 126. One end of an alarm circuit is connected to the contact 154 through terminals 156 and the other is connected to the casing 126. The device is attached to the door, or to a sleeve mounted in the door, through a spring which may be a leaf spring 178 or a bent wire (58 in Fig. 5). Attempts to prise the cylinder out of the door cause the device to tilt about pivot 50, 150 so that the circuit is completed by contact 154 engaging pin 168 set in the casing. The lock may be permitted to yield a short distance by mounting it by screw 120 through back plate 190 to a pressure plate 196 separated from plate 190 by springs. This allows sufficient movement to trigger the alarm but insufficient to damage the lock. Use of a skeleton key, a pick lock or an incorrect key will cause the pin tumbler 38aa to rise and push pin 60, sliding in slot 62 cut in the casing, into contact with contact 54 (see Fig. 5). Warning of attempts to force the door is given through another circuit, one end of which is connected to the casing 224 of rim lock 214 standing proud of the door 212, the other end being connected to contact plate 248. Pressure on the locked door 212 causes bolt 218 to press hard on its keeper 220 and so force the rim-lock 214, against the action of springs 236, against the contact plate 248 (see Fig. 12).