ADJUSTABLE-BACKSET LATCH SYSTEM FOR LOCKSETS, AND METHOD

An adjustable-backset latch system for a lockset includes three main subsystems; a bolt retraction system (12), a backset-adjustment system (14), and a deadlatching system (16). By virtue of thesimplicity of the design of the backset adjustment subsystem, theuser can change the backset from 2-3/8" to 2-3/4", and vice-versawith one hand. A pin (76) is simply moved through a "U"-shaped slot (68) formed in a housing (34) and the housing and bolt actuation components are extended simultaneously by the desired backset increment. The bolt retraction system of the present invention uses a cam (40) in which the distance from a point (42) about whichthe cam rotates and the end of the cam, and the distance to a smaller cam pin (46), are selected to multiply the relatively small angular distance transversed during a half-round rotation of the knob or handle into the desired retraction distance of a main bolt. The deadlatching system uses two springs (52, 54), one of which not only biases an auxiliary bolt (20) to its extended position, but also biases a deadlocking dog (118) so as to pivot into a blocking position preventing the main bolt from being retracted completely, in the event an intruder attempts to move the bolt.