Door lock attachment

Claim 1

A thumb knob and stop assembly including a spindle for cooperation with a door latch assembly comprising a body, means carried by the body for affixing it to a door, said body having a hole surrounded by a boss, a thumb-knob having a cylindrical hub rotably disposed and retained within the hole in said boss, a spindle coupling said hub and the door latch assembly when said body is secured to the door, said body having a slot lying along a line intercepting the axis of said hub, an actuating knob having a pin projecting therefrom and extending through said slot, said slidable knob being movable between first and second positions lengthwise of said slot, a stop member carried by said pin, said body further comprising spaced means lying along said line and forming a recess slidably engaging a first end of said stop, a recess in said boss also lying along said line and slidably receiving the other end of said stop member, whereby said stop member is restricted to sliding movement, a recess in said hub, said other end of said stop when in said first position extending through said boss and into the recess in said hub and restricting rotation thereof and in said second position being retracted from engagement with said hub, said stop further including biasing means and spring means contacting said biasing means whereby said spring means will maintain said stop in either its first or second positions.