Method of and machine for manufacture of block bottom bags

Claim 1

METHOD OF MANUFACTURING A BLOCK BOTTOM BAG HAVING LATERAL FOLDS DISPOSED INTERNALLY COMPRISING THE STEPS OF FEEDING A WEB OF MATERIAL IN LONGITUDINAL DIRECTION TO A FOLDING MACHINE, PROVIDING A LONGITUDINAL FOLD AND AN ADHESIVE ALONG BOTH EDGES OF A LONGITUDINAL SECTION PRIOR TO SEVERING SAID SECTION FROM SAID WEB OF MATERIAL, SEVERING SAID SECTION TRANSVERSELY OF SAID LONGITUDINAL DIRECTION FROM THE WEB TO FORM A LONGITUDINAL BLANK, FORMING A FIRST FOLD TRANSVERSELY OF THE DIRECTION OF FEED TO PRODUCE A SEAMLESS BOTTOM INTERMEDIATE THE PORTIONS CONSTITUTING THE SIDES OF THE BAG, FORMING A SECOND FOLD TRANSVERSELY OF THE DIRECTION OF FEED IN A DIRECTION OPPOSITE TO THAT OF SAID FIRST FOLD TO IMPART A Z SHAPE TO SAID BLANK INCLUDING SAID TWO TRANSVERSE FOLDS, FORMING A THIRD FOLD TRANSVERSELY OF THE DIRECTION OF FEED AND FOLDING OVER ONE SIDE ALONG SAID LAST FOLD IN A DIRECTION OPPOSITE TO THE DIRECTION OF FEED TO SUPERIMPOSE ONE SIDE ON THE OTHER.