Method of vacuum closing lined packages of cardboard

Claim 1

IN A METHOD OF CLOSING A FLEXIBLE, AIR-TIGHT LINING OF WELDABLE PLASTIC, AND CONTAINED INSIDE AN OUTER PACKAGE OF RELATIVELY STIFF MATERIAL, THUS FORMING A VACUUM PACKAGE HAVING A SUBSTANTIALLY TUBULAR SECTION BY HEAT SEALING THE OPEN END PORTION OF THE LINING BY PLASTIC WELDING, THE STEPS OF DIVIDING THE OPEN END PORTION INTO OPPOSITE EDGE SECTIONS EACH EXTENDING OVER APPROXIMATELY ONE-HALF PERIMETER AND BRINGING SAID OPPOSITE EDGE SECTIONS INTO ENGAGEMENT ALONG A STRAIGHT LINE TO FORM TRIANGULAR EARS AT EACH END OF THE SAID LINE WITH THE TRIANGULAR EARS EACH LYING FLAT AND SUBSTANTIALLY IN THE HORIZONTAL PLANE ALONG THE TOP OF AND OUTSIDE OF THE OUTER PACKAGE WITH A NARROW SLOT FORMED THEREINBETWEEN, HEAT SEALING THE EDGES SECTIONS TOGETHER BY WELDING ALONG SAID STRAIGHT LINE EXCEPT FOR A SHORT SEGMENT THEREOF IN ONE OF THE EARS, PLACING THE PACKAGE IN A CHAMBER AND CLOSING AND EVACUATING THE CHAMBER TO EVACUATE AIR IN THE PACKAGE THROUGH THE NARROW SLOT IN THE ONE SAID EAR AND SAID SHORT SEGMENT OF THE SEALING LINE AND HEAT SEALING THE SHORT SEGMENT BY PLASTIC WELDING TO COMPLETELY CLOSE THE LINING.