Folding door structure

Claim 1

IN A FOLDING DOOR OF THE TYPE COMPOSED OF A PLURALITY OF RIGID VERTICALLY ELONGATED PANELS, WHICH PANELS ARE OF HOLLOW CONSTRUCTION AND ARE HINGED TOGETHER SERIALLY ALONG THEIR VERTICAL EDGES BY FLEXIBLE HINGE STRIPS HAVING ENLARGED LONGITUDINAL BEAD-LIKE FORMATIONS ALONG OPPOSITE SIDE EDGES THEREOF SECURED IN RECESSES IN SAID VERTICAL EDGES, AND WHICH PANELS ARE ADAPTED TO BE EITHER FOLDED TOGETHER FACE-TO-FACE IN THE OPEN POSITION OF THE DOOR OR EXTENDED WITH RESPECT TO EACH OTHER IN THE CLOSED POSITION OF THE DOOR; THE IMPROVEMENT COMPRISING EACH PANEL HAVING ITS VERTICAL EDGE PORTIONS DEFINED BY A PAIR OF SPACED PARALLEL AND VERTICALLY EXTENDING PANEL FACINGS, AND A PAIR OF RELATIVELY NARROW VERTICALLY EXTENDING PANEL EDGINGS WHICH ARE LATERALLY SPACED APART FROM EACH OTHER AND ARE EMBRACED BETWEEN AND SECURED TO THE OPPOSITE VERTICAL SIDE MARGINS ONLY OF SAID PANEL FACINGS, EACH OF SAID EDGINGS BEING PROVIDED IN ONE OF ITS SIDE FACES TO WHICH A SIDE MARGIN OF A PANEL FACING IS SECURED IN OVERLAPPING RELATION WITH A VERTICALLY EXTENDING GROOVE, WHICH GROOVE OPENS OUTWARDLY ALONG SAID ONE SIDE FACE AND IS AT LEAST PARTIALLY COVERED BY THE OVERLAPPING MARGINAL PORTION OF THE PANEL FACING SECURED TO THAT FACE OF THE EDGING, SAID GROOVE BEING DIMENSIONED TO BE FILLED SOLELY BY A BEAD-LIKE FORMATION OF A FLEXIBLE HINGE STRIP, AND SAID GROOVE AND THE OVERLAPPING MARGINAL PORTION OF SAID PANEL FACING TOGETHER PROVIDING A PARTIALLY CLOSED POCKET RECEIVING THEREIN ONE OF THE BEAD-LIKE FORMATIONS OF THE ASSOCIATED FLEXIBLE HINGE STRIP WITH THE REMAINDER OF SAID HINGE STRIP PROJECTING FREELY OUTWARDLY BETWEEN SAID ONE SIDE FACE OF SAID EDGING AND THE SIDE MARGIN OF SAID PANEL FACING.