Abstract: A piston type lock employs stepped diameter pistons or pins and bores to prevent fallout of pins on disassembly and also multilevel surfaces at the lock rotor and housing interface such that one or more of the pins serve to retain the rotor in the housing in the unlocked condition of the lock.

Abstract: A key operated doorlock, which may incorporate a deadbolt, has a bolt housing that is mounted on the exterior of the door and is held there by being fastened to a spacer disposed within the door and a mounting plate at the interior side of the door. The main bolt is locked in place with a secondary locking apparatus which may include a barrel lock which operates a bolt which cooperates with a keeper opening in still another bolt. The latter engages a keeper opening that forms part of the housing. A lever system is provided which permits operation of the third bolt when permitted by the state of the second mentioned bolt.