Abstract: A plastic door lock, sometimes referred to as a door latch, makes use of moldable plastic material for most of the individual parts of the lock assembly 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. When used as a privacy lock unlocking the lock from the outside is prevented by pushing the inside knob into a releasable but non-rotatable engagement with the inside rose. A lost motion connection between the latch bolt and roll back 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, in cooperation with the movable latch bolt, releasably returns and holds the latch bolt in extended position.

Abstract: 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.

Abstract: A disengaging spindle locking mechanism for the latch bolt of a mortise type lock is actuated by the locking slide which is normally employed to engage a retractor hub to prevent the hub from being rotated. At the inner end of a split spindle where it is in non-rotatable engagement with the retractor hub there is a cam surface. On the inner end of a locking slide is a cam surface which cams the spindle out of engagement with the hub as hub action is blocked by the slide. Thereafter, should force be applied to the spindle, it will merely spin in place and no damage will be done to the lock mechanism such as might otherwise be done by unauthorized persons to force open the lock.

Abstract: A door latch makes use of moldable 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. Prior to installation of the latch on the door each knob is subassembled with the corresponding rose by employment of an arcuate shoulder on an inner central portion of the knob which is rotated to a position of engagement with a complementary arcuate shoulder in the rose. Rotation inhibiting detents prevent accidental disassembly until the spindle is mounted in place and the spindle then locks the knob against disassembly as long as the latch remains mounted on the door.