Packaging machine

Claim 1

IN A MACHINE FOR PRODUCING FILLED PACKAGES OF TETRAHEDRAL SHAPE, SAID MACHINE COMPRISING A VERTICAL MANDREL, MEANS FOR FORMING A TUBE OF PACKAGING MATERIAL AROUND THE MANDREL, THE TUBE BEING HEAT-SEALABLE ON THE INSIDE, A VERTICALLY RECIPROCABLE CARRIAGE BELOW THE MANDREL, FIRST AND SECOND PAIRS OF HEAT-SEALING HEADS CARRIED BY THE CARRIAGE FOR RECIPROCATION WITH THE CARRIAGE AND MOVEMENT RELATIVE TO THE CARRIAGE TOWARD AND AWAY FROM EACH OTHER TO FLATTEN THE TUBE AND TO FORM TRANSVERSE HEAT SEALS ACROSS THE TUBE AT PACKAGE LENGTH INTERVALS WITH SUCCESSIVE TRANSVERSE SEALS IN DIFFERENT PLANES AND ALTERNATE SEALS IN THE SAME PLANE SO AS TO PRODUCE PACKAGES OF TETRAHEDRAL SHAPE, MEANS FOR OPENING BOTH SAID PAIRS OF HEADS ON EACH UPWARD STROKE OF THE CARRIAGE AND FOR CLOSING FIRST ONE AND THEN THE OTHER OF SAID PAIRS OF HEADS ON SUCCESSIVE DOWNWARD STROKE OF THE CARRIAGE AND FOR CLOSING FIRST ONE AND THEN THE OTHER OF SAID PAIRS OF HEADS ON SUCCESSIVE DOWNWARD STROKES OF THE CARRIAGE, EACH PAIR OF HEADS WHEN CLOSED AND UPON A DOWNWARD STROKE OF THE CARRIAGE ACTING TO GRIP THE TUBE AND PULL A PACKAGE LENGTH THEREOF DOWNWARD: FIRST AND SECOND PAIRS OF GRIPPERS ASSOCIATED RESPECTIVELY WITH THE FIRST AND SECOND PAIRS OF HEADS AND CARRIED BY THE CARRIAGE FOR RECIPROCATION WITH THE CARRIAGE AND FOR MOVEMENT RELATIVE TO THE CARRIAGE, EACH PAIR OF GRIPPERS BEING POSITIONED TO CLAMP THE TUBE ON A LINE EXTENDING TRANSVERSELY ACROSS THE TUBE ADJACENT THE HEAT SEAL FORMED BY THE RESPECTIVE PAIR OF HEADS, AND MEANS FOR CONTROLLING EACH PAIR OF GRIPPERS TO CLAMP THE TUBE UPON CLOSURE OF THE RESPECTIVE PAIR OF HEADS WHEN THE CARRIAGE MOVES DOWNWARD AND TO MAINTAIN THE GRIPPERS CLAMPED ON THE TUBE UNTIL AFTER RESPECTIVE HEADS HAVE STARTED TO OPEN AT THE TERMINATION OF A DOWNWARD STROKE OF THE CARRIAGE.