GB1193760A - Cylinder Lock - Google Patents

Abstract

1,193,760. Cylinder locks. GENERAL ALARM CORP. 19 June, 1968 [28 June, 1967], No. 29127/68. Heading E2A. A cylinder lock, incorporating means for actuating an alarm if an attempt is made to pick the lock, by applying a torque to the barrel and raising successive pins until the shear line is felt, and at the same time frustrating such attempt, comprises a key-operated barrel 12, which incorporates at least one pin 16 associated with a standard driver 17 and spring 19 located in a bore 15 of the cylinder casing, a second barrel 11 arranged side by side with the first barrel so that the juxtaposition of the two barrels forms an extension of the shear line, and pins 21 cooperating with non-standard driver assemblies in normally aligned bores 11a, 12a of the two barrels, the non-standard driver assemblies being designed such that, when the standard pin and driver have been picked by the above method, limited rotation of both barrels in opposite directions occurs through the interconnection provided by the non-standard driver assemblies, resulting in rotation of an axial extension 31 of the barrel 11, which causes, an arm 32 to operate a micro-switch in an alarm, circuit. In the embodiment of Figs. 1 and 2, each of the non-standard driver assemblies consists of an axially short driver 22 and a spring having a close-wound portion which normally extends across the shear line. As a result, as soon as the pin 16 has been picked, the barrel 12 is freed and rotary motion is transmitted to the barrel 11 by the springs of the non-standard assemblies, sucn relative rotation however being limited by interference between formations 27, 29 on the two barrels, which prevents the bolt from being completely withdrawn. By the provision of a spring-loaded ball 40 in barrel 11 engageable with either of two recesses 42 in the casing, the barrel 11 is locked in the alarmoperating position. A further spring-loaded ball is provided in a bore 50 in the casing cooperable with a recess 47 in the barrel 11 to releasably hold the latter in its normal position when the correct key is inserted, so that in this case barrel 12 rotates independently, the portions 27, 29 do not interfere, and the bolt is withdrawn. In a second embodiment, Fig. 7, each of the non-standard driver assemblies consists of a spring 44 and a driver 45 which co-operates with an enlarged bore 11b in the barrel 11, thus eliminating the need for the interfering formations, 27, 29 of the previous embodiment.