Cord locking device

Claim 1

A locking device consisting of two pieces for a cord passing twice therethrough, comprising: (a) hollow sleeve of synthetic resin having a rectangular cross-section with a rectangular bore open at one end, the length of said sleeve being considerably longer than the width of its cross-section, said sleeve having a pair of aligned rectangular openings near said one open end for enabling the cord to pass twice therethrough, said rectangular openings having a width larger than their height, and lying in the wider sides of said rectangular sleeve, the wider marginal edges of said sleeve openings being a sharp tapered edge directed away from said open end and disposed adjacent to the void space of said sleeve, said sleeve having at least one longitudinal ridge disposed within said open end and extending substantially to one of said openings and terminating in a ledge facing away from said open end; and (b) a movable slide of synthetic resin material having a portion slidably disposed in said bore of said sleeve, a rectangular head integral with said portion and having a planar dimension larger than said bore and defining a flange engageable with the end of said sleeve, and a spring integral with said slide portion, said portion, said head and said spring being continuously molecularly bonded, said spring being a continuous zigzag web of plastic disposed in said bore and biasing said slide toward said open end of said sleeve, said spring having a prismatic outer contour, said slide having an opening lying in a plane between and registerable with said rectangular sleeve openings when said flange is engaged, an edge of said slide opening comprising an abutment directed toward and engageable with said ledge on said sleeve to retain said slide in said sleeve when no core is present, said spring being only partially compressed when said ledge is engaged, and when said flange is engaged, a single sharp longitudinal edge adjacent to said abutment in said slide opening and disposed out of registration with said marginal edges of said sleeve-opening, and said slide having a groove for each said longitudinal ridge in which said ridge and said ledge is received, said groove extending from said head to said slide opening.