Backset-adjustable latch of a cylindrical lock

Claim 1

A backset-adjustable latch bolt mechanism for a cylinder lock, comprising: a latch bolt case having a flanged front defining an opening therein, said latch bolt case housing: a latch bolt means including a latch bolt, said latch bolt being biased in a protruding position to protrude forward out of said housing through said opening and being rearwardly retractable into a retracted position through said opening into said case housing, and a laterally slotted latch bolt extension slide, joined, at a forward end thereof, to a rearward end of said latch bolt, a latch bolt guard means for limiting rearward movement of said latch bolt into said case housing when said latch bolt is in said protruding position, including a retractable guard bolt positioned flush against a lateral face of said latch bolt, a laterally slotted guard bolt extension slide connected at a forward end thereof to a rearward end of said guard bolt, said guard bolt extension slide having an arm depending therefrom, and a stopping plate movable in and out of a retracting path followed by said latch bolt extension slide when said latch bolt is moved from said protruding position to said retracted position, said arm causing said stopping plate to block said retracting path when said latch bolt guard is in a retracted position while said latch bolt is in said protruding position; a slotted retractor slide; a latch base board, having a bore therein through which extend said latch bolt extension slide, said guard bolt extension slide, and said retractor slide; a latch confining board, fixed to a rear end of said casing, having a bore in which a rearward end of said retractor slide is fixed; said retractor slide having a protrusion for slidably extending through said slot of said lock bolt extension slide, means defining a hole, positioned a lateral distance from said protrusion equal to a desired backset adjustment, for receiving a removable connecting pin capable of slidably fitting through and connecting the slots of said latch bolt extension slide, said retractor slide, and said guard bolt extension slide, a first nose portion having a first valley for resting said latch base board therein and a second nose portion having a second valley for resting said latch base board therein, said first and second valleys being spaced said longitudinal distance apart; said casing having a front section and a rear section coaxial and slidable relative to each other, one of said front section and said rear section being an inner section, the other section being an outer section, a depressable button extending radially outward from said inner section, said outer section having a means defining a first hole and a means defining a second hole on said outer section, said first and second holes being spaced said longitudinal distance from each other, for receiving said button; whereby, when said button is depressed into one of said holes, said removable pin has been removed, and said latch board is resting in one of said valleys, said case sections may be slid apart to cause said respective nose portion of said retractor slide to slide upon said latch base board, lifting said retractor slide until said latch base board is set with said other valley and said button has been received in said other hole, thus adjusting the backset of said latch bolt mechanism.