Apparatus for manufacturing bags

Claim 1

APPARATUS FOR OPERATING ON GUSSETED BAG TUBES TO FORM A BOTTOM AT ONE END OF EACH TUBE, WITH THE BOTTOM BEING OF THE TYPE COMPRISING INWARDLY DIRECTED END FLAPS AND SIDE FLAPS ONE OVERLAPPING THE OTHER, SAID APPARATUS COMPRISING A ROTARY DRUM, MEANS FOR CONTINUOUSLY DRIVING THE DRUM, MEANS FOR FEEDING GUSSETED BAG TUBES ONE AFTER ANOTHER ENDWISE TOWARD THE DRUM, AT LEAST ONE BOTTOM-OPENING MECHANISM CARRIED BY THE DRUM FOR OPERATING ON THE LEADING END OF EACH BAG TUBE FED ENDWISE THERETO TO OPEN UP A BOTTOM AT SAID LEADING END OF EACH TUBE, SAID BOTTOM-OPENING MECHANISM COMPRISING TWO GRIPPER UNITS SPACED APART LATERALLY ON THE DRUM FOR OPERATING ON OPPOSITE SIDES OF A BAG TUBE, EACH GRIPPER UNIT COMPRISING A FIRST GRIPPER FOR GRIPPING THE RADIALLY INNER FOLD OF THE GUSSET OF THE BAG TUBE AT THE RESPECTIVE SIDE OF THE TUBE, AND A SECOND GRIPPER FOR GRIPPING THE RADIALLY OUTER FOLD OF THE GUSSET AT THE RESPECTIVE SIDE OF THE TUBE, SAID FIRST GRIPPERS BEING ADAPTED TO GRIP THE RADIALLY INNER FOLDS OF THE GUSSETS AT OPPOSITE SIDES OF THE TUBE AND HOLD THEM STATIONARY RELATIVE TO THE DRUM, SAID SECOND GRIPPERS BEING ADAPTED TO GRIP THE RADIALLY OUTER FOLDS OF THE GUSSETS AT OPPOSITE SIDES OF THE DRUM AND BEING PIVOTALLY MOUNTED ON THE DRUM FOR SWINGING MOVEMENT RELATIVE THERETO FROM A FIRST ANGULAR POSITION WHEREIN THEY ARE POSITIONED TO GRIP THE OUTER GUSSET FOLDS AT POINTS OUTWARD OF THE FIRST GRIPPERS TO A SECOND ANGULAR POSITION TRAILING THE FIRST GRIPPERS FOR OPENING UP A BOTTOM AT SAID LEADING END OF THE TUBE WITH THE OPENED-UP BOTTOM COMPRISING INWARDLY DIRECTED END FLAPS AND LEADING AND TRAILING FLAPS, SAID FIRST AND SECOND GRIPPERS BEING MOUNTED FOR LATERAL INWARD AND OUTWARD MOVEMENT RELATIVE TO THE DRUM BETWEEN A RETRACTED POSITION OUTWARD OF THE SIDES OF A TUBE AND AN INNER POSITION WHEREIN THEY ARE ADAPTED TO GRIP THE GUSSET FOLDS, GRIPPER ACTUATING MEANS FOR MOVING THE GRIPPERS INWARD FROM THEIR RETRACTED POSITION WITH THE GRIPPERS OPEN, THEN CLOSING THE GRIPPERS IN TIMED RELATION TO THE FEED OF THE BAG TUBES FOR GRIPPING THE GUSSET FOLDS OF A TUBE, AND THEN SWINGING THE SECOND GRIPPERS TO SAID SECOND ANGULAR POSITION, AND MEANS FOR BIASING OUTWARD BOTH THE FIRST AND SECOND GRIPPERS OF AT LEAST ONE OF THE GRIPPER UNITS WHILE THE GRIPPERS ARE GRIPPING THE GUSSET FOLDS TO STRETCH THE WALLS OF THE TUBE LATERALLY AND FOR BIASING ONE OF THE GRIPPERS OF EACH UNIT CIRCUMFERENTIALLY OF THE DRUM FOR STRETCHING THE END FLAPS, SAID GRIPPER ACTUATING MEANS INCLUDING CAM MEANS FIXED RELATIVE TO THE DRUM AND CAM FOLLOWER MEANS ROTARY WITH THE DRUM FOR CONTROLLING INWARD AND OUTWARD MOVEMENT OF THE FIRST AND SECOND GRIPPERS OF EACH GRIPPER UNIT, SAID CAM MEANS BEING FORMED TO ACT VIA SAID CAM FOLLOWER MEANS TO MOVE THE FIRST AND SECOND GRIPPERS OF EACH GRIPPER UNIT INWARD TO THE INNER POSITION FOR GRIPPING THE GUSSET FOLDS OF A TUBE AND TO RELEASE BOTH THE FIRST AND SECOND GRIPPERS OF SAID ONE GRIPPER UNIT AFTER THE GRIPPERS HAVE GRIPPED THE GUSSET FOLDS OF A TUBE FOR OUTWARD BIAS BY SAID BIASING MEANS OF BOTH SAID FIRST AND SECOND GRIPPERS OF SAID ONE GRIPPER UNIT WHILE GRIPPING THE GUSSET FOLDS OF A TUBE TO STRETCH THE WALLS OF THE TUBE LATERALLY.