Plastic latch bolt for door lock

摘要

A plastic door lock makes use of moldable plastic material for most of the individual parts with opposite roses adapted to interlock with each other and be held together with a single screw on the axial center line of the knobs and accessible from the outside. A lost motion connection between the latch bolt and spindle allows the door to be closed without damage to the latch bolt when the inside knob is locked. Inherent resiliency in the material of the latch bolt case formed into spring fingers, in cooperation with the movable latch bolt shaft, releasably returns the latch bolt shaft to, and holds the shaft in extended position. Under some circumstances spring action of the fingers is supplemented with an auxiliary separate spring element to vary the spring return characteristics of the latch bolt and the knobs.