Spacer for double glazed windows incorporating interlock means

Claim 1

A spacer tube for a hermetically sealed double glazed window, the spacer tube being formed from an elongated strip of metal bent into a hollow elongated tubular shape, the spacer tube having opposing side wall portions, a base extending between and connecting the side wall portions and a further wall spaced from the base, such further wall defining a region wherein the longitudinal edges of the strip extend toward each other, and wherein a surface of the spacer tube which faces into the interior of the spacer tube has a plurality of closely spaced ridges therein, said surface having said ridges therein being the interiorly facing surface of said base, the ridges being spaced apart in the lengthwise direction of the spacer tube and the individual ridges extending generally transversely of the longitudinal axis of the spacer tube, the ridges being located at least in the regions adjacent the ends of the spacer tube whereby, in use, to provide for locking engagement with teeth on the arms of corner pieces when inserted endwise into the ends of the spacer tube, said base being shaped in cross-section so as to define a crest projecting a short distance into the interior of the hollow spacer tube, said transversely disposed ridges being formed in said crest.