Method and apparatus for folding containers having a window of synthetic plastic sheet material

Claim 1

IN THE METHOD OF FOLDING WINDOW CONTAINERS, THE STEPS COMPRISING PARTIALLY FOLDING A BLANK HAVING A FRAME OF RELATIVELY RIGID SHEET MATERIAL WITH A MULTIPLICITY OF WEAKENING LINES THEREIN DEFINING WALL PANELS TO PROVIDE THE SIDES OF A CONTAINER TO BE ERECTED THEREFROM, SAID FRAME HAVING A WINDOW APERTURE THEREIN EXTENDING ACROSS ONE OF SAID WEAKENING LINES INTO TWO OF SAID WALL PANELS AND SAID BLANK HAVING A WINDOW OF SEMI-RIGID SYNTHETIC PLASTIC SHEET MATERIAL SECURED TO SAID FRAME AND EXTENDING BEYOND THE MARGINS OF SAID WINDOW APERTURE, SAID PARTIAL FOLDING OF SAID BLANK BEING ALONG SAID ONE WEAKENING LINE AND WITH SAID WINDOW DISPOSED INWARDLY OF SAID FOLDING; FURTHER FOLDING SAID PARTIALLY FOLDED BLANK BETWEEN A PAIR OF CLOSELY SPACED PRESSURE MEMBERS TO FLATTEN AND FOLD SAID BLANK SUBSTANTIALLY COMPLETELY ALONG SAID ONE WEAKENING LINE, ONE OF SAID PRESSURE MEMBERS HAVING A RESILIENTLY DEFORMABLE SURFACE, SAID FLATTENING AND FOLDING PRODUCING A RELATIVELY PERMANENT FOLD LINE IN SAID WINDOW SUBSTANTIALLY ALIGNED WITH SAID ONE WEAKENING LINE IN SAID FRAME; UNFOLDING SAID BLANK ALONG SAID ONE WEAKENING LINE AND FOLD LINE; AND FLATTENING SAID UNFOLDED BLANK BETWEEN A SECOND PAIR OF CLOSELY SPACED PRESSURE MEMBERS ALONG SAID ONE WEAKENING LINE AND FOLD LINE TO FLATTEN SUBSTANTIALLY SAID WINDOW ALONG SAID FOLD.