Apparatus for vacuum packaging

Claim 1

APPARATUS FOR MAKING STEP-BY-STEP A BAND OF CLOSED BOXES, EACH CONTAINING A DETERMINED QUANTITY OF A PRODUCT, FROM A FIRST STRIP OF FLEXIBLE MATERIAL FORMED WITH A LONGITUDINALLY EXTENDING SERIES OF OPEN-TOPPED BOXES CONTAINING SAID QUANTITY OF PRODUCT AND A SECOND FLAT STRIP OF MATERIAL, COMPRISING IN COMBINATION: AN EVACUABLE ENCLOSURE COMPRISING FIXED UPPER ENCLOSING MEANS AND MOVABLE LOWER ENCLOSING MEANS, SAID UPPER AND LOWER ENCLOSING MEANS COOPERATING TO PROVIDE A SUBSTANTIAL GAS-TIGHT ENCLOSURE WHEN SAID MOVABLE LOWER ENCLOSING MEANS IS IN ITS UPPER POSITION, WHILE MOVEMENT OF SAID MOVABLE LOWER ENCLOSING MEANS TO ITS LOWER POSITION PROVIDES AN INLET APERTURE FOR ENTRY OF AN OPEN-TOPPED BOX OF SAID FIRST STRIP AND A PORTION OF SAID SECOND FLAT STRIP INTO SAID ENCLOSURE; DRAWING MEANS FOR ADVANCING STEP-BY-STEP INTO SAID ENCLOSURE AN OPEN-TOPPED BOX OF SAID FIRST STRIP CONTAINING SAID DETERMINED QUANTITY OF SAID PRODUCT AND A PORTION OF CORRESPONDING LENGTH OF SAID SECOND STRIP WITH SAID PORTION OF SAID SECOND STRIP IMMEDIATELY ABOVE SAID OPEN-TOPPED BOX; MEANS FOR REDUCING THE PRESSURE WITHIN SAID ENCLOSURE TO A VALUE BELOW ATMOSPHERIC PRESSURE; A HEAT SEALING ELECTRODE DISPOSED IN SAID ENCLOSURE ABOVE THE POSITION ASSUMED BY SAID PORTION OF SAID SECOND STRIP, THE LOWER PART OF SAID ELECTRODE HAVING THE SHAPE OF THE CONTOUR OF SAID OPEN-TOPPED BOXES; ELECTRODE ADVANCING MEANS FOR MOVING SAID ELECTRODE DOWNWARDLY INTO CONTACT WITH SAID CONTOUR, THEREBY SEALING THE PORTION OF SAID SECOND STRIP TO THE OPENTOPPED BOX CONTAINING SAID QUANTITY OF PRODUCT TO FORM A GAS-TIGHT CLOSED BOX CONTAINING SAID QUANTITY OF PRODUCT WHILE THE PRESSURE WITHIN SAID ENCLOSURE IS MAINTAINED TO SAID VALUE BELOW ATMOSPHERIC PRESSURE, WHEREBY, UPON RESTORING THE PRESSURE WITHIN SAID ENCLOSURE TO ATMOSPHERIC PRESSURE, A PRESSURE DIFFERENTIAL IS CREATED BETWEEN THE OUTSIDE AND THE INSIDE OF SAID GAS-TIGHT CLOSED BOX WHICH PRODUCES A MOTION OF AT LEAST ONE SIDE OF SAID FLEXIBLE MATERIAL FORMING SAID CLOSED BOX THEREBY CAUSING SAID DETERMINED QUANTITY OF SAID PRODUCT INSIDE SAID BOX TO FILL SUBSTANTIALLY UNIFORMLY SAID GAS-TIGHT CLOSED BOX, AND MEANS FOR REPEATING THE STEP-BY-STEP CYCLE OF ADVANCING SAID FIRST AND SECOND STRIP, REDUCING THE PRESSURE WITHIN SAID ENCLOSURE, SEALING SAID BOX AND RESTORING THE ATMOSPHERIC PRESSURE WITHIN SAID ENCLOSURE.