DISC TUMBLER LOCK AND KEY

摘要

A tubular lock of the kind having a body and a barrel assembly which is mounted within the body for relative rotation about an axis. The assembly includes a tubular sleeve (4) and a number of disc tumblers located within the sleeve (4) so that each is rotatable relative to the sleeve and relative to one another about the axis. A side locking bar (9) is operative to prevent rotation of the assembly relative to the body, and that bar is rendered inoperative by insertion of a correct key into the lock keyway. The disc tumblers rotate in response to insertion of a key into the keyway and include a number of standard tumblers and a special tumbler. The locking bar (9) is inoperative when each standard tumbler is at a service position of rotation and the special tumber is at either a service position or a second function position of rotation. A service key (20) is operable to place all tumblers at the service position, and a special change key is operable to place the special tumber at the second function position and to place all other tumblers at the service position. When the special tumbler is at the second function position it releases a movable detent (23) which is otherwise operative to prevent axial removal of the assembly (2) from the body. But such removal is not possible until the change key is turned to rotate the assembly to a position at which a fixed detent (28) is aligned with a longitudinal groove (33) of the body. The key (20) is formed by use of a computer controlled machine which enables selection of any one of a number of key forming operation sequences, each of which produces a key (20) having characteristics to suit a particular lock.