Duplex latch bolt mechanism

Abstract

The mechanism is used with a latch-bolt unit (including a latch-bolt head) and a latch-handle assembly, for installation in a door. The novel mechanism includes a retracting member (connected to retract the latch-bolt head), with two different sets of extracting teeth to accommodate two different standard door-lock backset configurations of standard commercial doors. A connecting device, made up of first and second coupling members as well as a movable configuration-selector plate, is connected at the rear of the latch-bolt unit. The connecting device has two different sets of screw openings and clearing spaces. Its selector plate selectively effectuates either of these two different sets of connecting points, corresponding to the two standard backsets. The selector plate is thus used to adjust the latch-bolt mechanism quickly and easily, to accommodate the preferred door-lock backset--without any modification such as cutting or bending. The selector plate provides a telescoping action, so that the connecting device does not extend into the door substantially beyond the latch-bolt handle assembly; consequently the door-edge bored hole need not be any deeper than necessary. The telescoping action is an exclusively linear, one-stage adjustment motion.