Method of producing welded double glazing units

Claim 1

IN A METHOD OF FORMING AN ALL-GLASS, ELECTRICALLY FUSED, DOUBLE GLAZING UNIT, WHEREIN A LARGER OF TWO FLAT GLASS SHEETS IS SUPERPOSED ABOVE A SMALLER OF THE TWO SHEETS IN SPACED RELATION AND EXTENDS A SUBSTANTIALLY EQUAL AMOUNT BEYOND THE VERTICAL PLANES OF EACH MARGINAL EDGE OF THE LOWER SHEET AND WHEREIN THE LARGER SHEET HAS CONNECTING LONGITUDINAL STRIPES OF ELECTRICALLY CONDUCTIVE MATERIAL ADJACENT EACH MARGIN THEREOF, THE IMPROVEMENT COMPRISING SUPPORTING A CENTRAL PORTION OF THE LOWER SHEET IN A PREDETERMINED PLANE AND SUPPORTING MARGINAL PORTIONS OF THE LOWER SHEET IN SAID PREDETERMINED PLANE ONLY AT LOCATIONS SPACED FROM EACH OTHER ABOUT THE MARGIN OF THE LOWER SHEET, SAID LOWER SHEET BEING UNSUPPORTED ALONG SUBSTANTIAL MARGINAL PORTIONS THEREOF DISPOSED WITHIN THE AREA OF FUSION AND CYCLING ELECTRIC CURRENT THROUGH THE STRIPES AT A RATE SUFFICIENTLY RAPID TO HEAT SOFTEN AND FUSE THE EDGES OF THE UPPER AND LOWER SHEETS TOGETHER BEFORE UNSUPPORTED PORTIONS OF THE MARGIN OF THE LOWER SHEET BECOME SUFFICIENTLY SOFTENED TO DISTORT UNDER THE WEIGHT OF THE UNIT WHEREBY THE UNSUPPORTED MARGINAL EDGE BECOME ROUNDED AND FIRE-POLISHED.