Method and apparatus for producing evacuated packages

Claim 1

AN IMPROVED METHOD FOR CLOSING AND SEALING TRAY TYPE PACKAGES COMPRISING: DEPOSITING PRE-FORMED OPEN TOPPED TRAYS SEQUENTIALLY INTO AN ENDLESS SERIES OF ALIGNED ANVIL MEANS, SAID ANVIL MEANS CONFORMING TO THE SHAPE OF SAID TRAYS AND BEING LONGER THAN SAID TRAYS IN THE DIRECTION OF ALIGNMENT; MOVING SAID TRAYS AND SAID ANVIL MEANS STEPWISE IN A GIVEN DIRECTION IN LINE WITH SAID ALIGNMENT; FILLING PRODUCT IN EACH OF SAID OPEN TRAYS UPON EACH TRAY MOVING PAST A GIVEN POINT; DRAWING A FILM OF TOP CLOSURE MATERIAL ACROSS THE PRODUCT AND A FIRST TRAY AND SAID ANVIL MEANS IN SAID GIVEN DIRECTION SO AS TO OVERLAP THE FORWARDMOST EDGE OF SAID TRAY; SEALING SAID FILM TO THE FORWARDMOST EDGE OF SAID FIRST TRAY; SEVERING THE FILM JUST FORWARD OF SAID FORWARDMOST EDGE FROMT THE PRECEDING PORTION THEREOF SIMULTANEOUSLY WITH SAID SEALING; MOVING SAID ANVIL MEANS CONTAINING THE TRAY AND FILM SEALED THERETO IN SAID GIVEN DIRECTION WHILE RETARDING THE FORWARD MOVEMENT OF SAID TRAY AND FILM UNTIL THE REAR OF SAID ANVIL MEANS PUSHES SAID TRAY AND FILM SEALED THERETO IN SAID GIVEN DIRECTION, WHEREBY SAID FILM IS DRAWN ACROSS THE REMAINDER OF SAID FIRST TRAY AND THE FORWARDMOST EDGE OF THE NEXT TRAY; THEREAFTER FINALLY SEALING THE FILM TO THE REARMOST AND REMAINING EDGE OF SAID FIRST TRAY AND SIMULTANEOUSLY SEALING THE FORWARDMOST EDGE OF THE NEXT TRAY AND SEVERING THE FILM BETWEEN SAID TRAYS; AND MOVING SAID ANVIL MEANS AND TRAYS FURTHER IN SAID GIVEN DIRECTION.