Abstract: A pin tumbler lock has a rotary plug with three rows of tumbler pin mounting holes to accommodate a large number of tumblers. Rotational control of the plug is by means of a stop plate carried on a stem which is an integral extension of the plug. The lock cylinder has a rearwardly extending tab having its opposite side edges in registration with stop surfaces on the stop plate to limit the plug motion in two directions. The lock may be shortened by such provision of exterior rotational control to provide a shortened locking dimension and/or to accommodate a substantial number of pins and tumblers.

Abstract: A key-operated lock has a shell mounted securely in a closure, and a removable lock-actuator cartridge insertable into and withdrawal from the shell to facilitate changing the tumbler disk combination in the lock. The cartridge includes an annular hollow housing seatable in the shell, and a tumbler disk carrier telescopically insertable into the housing. The carrier and associated tumbler disks are rotatable within the housing to operate the lock. An anti-damage feature comprises the cartridge being insertable into the open front end of the shell. A thickened rear wall of the shell reinforces the cartridge against destructive attack by rod and hammer action exerted on the front face of the lock. Principal features are quick changing of the tumbler disk pattern, and a rigid damage-resistant lock structure.

Abstract: A key lock having a hardened steel plug that protects the internal tumblers from attack by vandals or thieves. The lock includes a high strength locking bolt that is biased to its latching position by a novel coil spring; a stabilizer rod extends within the spring to prevent lateral buckling of the spring convolutions.