GB1376011A - Cylinder lock - Google Patents

Abstract

1376011 Locks KEYSTONE CONSOLIDATED INDUSTRIES Inc 24 Jan 1972 3312/72 Heading E2A A change-key barrel lock comprises an axial-tumbler, rotatable barrel assembly 31, 34, 28 of known type, provided with radially movable pins 68 which are normally biassed inwardly by O-ring 69 so as to clear indexing notches 65, 66 in an indexing ring except when a correct key 79 is inserted. This key has notches 89 to receive the inner ends of pins 68, so that the key can rotate the barrel and can only be withdrawn in its 'locked' position, and a special key 91 is required for changing the disposition of tumblers 55, 56, 57 to receive a changed key bitting. In normal use, the key 79 raises pin 78 against resilient ring 62 so that its interface with a follower 76 coincides with the interface between the barrel 31 and the index ring 61, thus permitting rotation. The key is splined at 39, 85 to a central spindle 36 which carries the rotatable element 31 and 28, and also a locking bolt (11, not shown). The change-key 91 has a slot 97 for accommodating the pin 68 at its top surface but is completely relieved at 98 at its bottom. In consequence it may be turned 30‹ to a displaced position 26 and withdrawn leaving the top pin 68 in a displaced slot 66 in the detent ring. A change-key with a different bitting can then be inserted and rotated to the 'locked' position. The effect of this is to change the arrangement of the change tumblers 57 relative to tumblers 55 and locking tumblers 56. As shown, the lock is of axial tumbler type for use with keys having appropriate bitting 88, but a radial pin or plate tumbler lock could be used.