Latch bolt operating assembly having bolt operating improvements

Abstract

Retracting motion is imparted through door knobs or levers into a transverse half-round spindle which, in turn, longitudinally moves a retractor slide. The retractor slide is forwardly pivotally connected through a link to a cam having its rearward end pivotal on the frame and its forward end engaged with a main bolt. The main bolt is a spring latch bolt connected to the cam by a slideable unlocking slide movably enclosed by a U-shaped bolt extension with the unlocking slide also actionable with a locking dog controlled by an auxiliary bolt. In normal operation the main bolt is extended within a strike plate and the auxiliary bolt is retracted bearing against the strike plate so that rearward movement rearwardly pivots the cam which withdraws the main bolt through rearward abutment of the unlocking slide which bears rearwardly against the bolt extension, the auxiliary bolt also being withdrawn due to the unlocking slide ultimately acting against the locking dog and the auxiliary bolt. When, however, attempts are made to drive the main bolt from its extended position by forces against the main bolt, the cam and unlocking slide remain stationary and the bolt and bolt extension move rearwardly independently which causes the locking dog to ultimately dog the main bolt in its extended position frustrating the driving attempt. A backset adjustment may also be provided, a forward backset by an insert engaged with the retractor slide transmitting motion from the spindle into the insert and ultimately into the retractor slide, and a rearward backset adjustment being merely the retractor slide with the inserts removed.