Ceiling runner locking means

Claim 1

In a ceiling suspension system comprising at least two runners, each runner having an elongated sheet metal body member and a generally inverted U-shaped configuration, said runner having two side walls connected together at their one ends with a flat top member, the opposite ends of the side walls having horizontal flanges which extend outwardly from the body of the runner to support ceiling boards on either side of the runner, said side walls having a first groove means therein, said first groove means extending outwardly from the side walls to form two parallel ledges inside the U-shaped body configuration, said first groove means extending below and outwardly of the parallel ledges to form an overhang and being in the mid region of the side walls, a second groove means positioned in the side walls closely adjacent the horizontal flanges, said second groove means forming a projection which projects outwardly from the side wall, the end of one runner abutting the side of a second runner, said second runner having its side and adjacent flange partially cut away to form a cutout area, said end of the other runner having a portion of the end cut away to form two hook elements on said side walls, said hook elements engage the side walls of the second runner under the overhang just above the cutout area, the improvement comprising a projection formed on the side of each said second groove means at the end of a runner and at the cutout area of a runner, a notch cut in the back side of each projection, said end of each runner and said cutout area on the side of each runner having the projections and notches so formed that the notches engage each other and the projections overlap each other to lock together the end of one runner to the side of another runner.