Method and apparatus for the manufacture of a square-bottom-bag of a weldable material

Claim 1

A DEVICE FOR MANUFACTURING FLAT-BOTTOM BAGS OF WELDABLE MATERIAL FROM TUBULAR STOCK, COMPRISING IN COMBINATION, A SUCTION DEVICE ADAPTED TO OPEN ONE END OF A FLATTENDED TUBULAR SECTION OF WELDABLE MATERIAL, SAID SUCTION DEVICE INCLUDING A SUCTION PLATE, AIR SUCTION MEANS OPERATIVELY MOUNTED IN SAID SUCTION PLATE FOR HOLDING THE LOWER WALL OF SAID FLATTENED TUBULAR SECTION, A PAIR OF SUCKER ARMS PIVOTABLY MOUNTED IN SAID DEVICE ABOVE SAID SUCTION PLATE AND ADAPTED TO ENGAGE THE UPPER WALL OF SAID FLATTENED TUBULAR SECTION AND OPEN THEREBY SAID END OF SAID FLATTENED TUBULAR SECTION, A PLATE FIXEDLY MOUNTED ADJACENT SAID SUCTION PLATE AND ADAPTED TO DEFINE A CENTER FOLD IN THE TUBULAR STOCK AND TO SUPPORT A PORTIO OF SAID UPPER WALL OF SAID TUBULAR SECTION WHICH IS FOLDED BCK DURING THE OPENING OF THE END THEREOF, A PAIR OF SPREADER ARMS SWINGABLY MOUNTED IN SAID DEVICE ADJACENT TO SAID SUCTION PLATE AND ADAPTED TO SPREAD THE OPENED END OF SAID TUBULAR SECTION UNTIL SAID END ASSUMES A SUBSTANTIALLY FLAT CONFIGURATION WITH A PAIR OF CORNER FOLDS, BASE SHEET FEEDING MEANS OPERATIVELY MOUNTED IN SAID DEVICE AND ADAPTED TO POSITION AT LEAST ONE BASE SHEET ON SID END OF SAID TUBULAR SECTION SPREAD BY SAID PAIR OF SPREADER ARMS SO THAT THE EDGES OF SAID PAIR OF CORNER FOLDS ARE COVERED BY SAID BASE SHEET AND WELDING JAW MEANS OPERATIVELY MOUNTED IN SAID DEVICE AND ADAPTED TO WELD SAID BASE SHEET TO SAID END WHILE THE LATTER IS BEING SPREADINGLY HELD BY SAID PAIR OF SPREADER ARMS.