CYLINDER LOCK AND ITS ASSOCIATED KEY

摘要

A rotatable disc having a tubular lock assembly including a tubular sleeve and a number of disc tumblers located within the sleeve. A side locking bar is operative to prevent rotation of the assembly relative to a body, and that bar is rendered inoperative by insertion of a correct key into the lock keyway. The disc tumblers include a number of standard tumblers and a special tumbler. The locking bar is inoperative when each standard tumbler is at a service position of rotation and the special tumbler is at either a service position or a second function position of rotation. A service key is operable to place all tumblers at the service position, and a special change key is operable to place the special tumbler at the second function position to allow removal of the barrel assembly.