Abstract: A mortise lock has two relatively-rotatable knob or lever-controlled spindles for independent operation from opposite sides of a door of a resiliently extending latchbolt and positively extending deadbolt, and stop buttons accessible at an edge of the door for blocking operation of the bolts from one side in a higher security state. The lock also has a safeguard effective to block a change in the state of the stop buttons to a lower-security state unless the deadbolt is first positioned at a pre-determined point between full retraction and full extension using a key. The lock is a double cylinder lock such that operation of the deadbolt from either side requires a key. The lock may be mastered such that operation of the deadbolt requires a master key while operation of the latch requires a common key. Therefore the ability to change the stop buttons is restricted.

Abstract: A door handle mount for a door having a rotatable spindle for operating a latch includes a lever handle cantilevered on the spindle and a trim plate having a spring resiliently biasing the spindle to seek a home position. The home position sought by the trim plate spring may be changed by relocating a movable stop. The user selectively biases the home position of the spindle to accommodate the cantilevered weight of the lever handle, to alter the bias from one direction to the other, or to temporarily cancel the bias during installation of the latch mechanism and trim.