Abstract: A method and apparatus for the manufacture of inflatable liners for disposable dunnage bags. The apparatus includes means for measuring and severing an indefinite length of flattened tubular plastic material into predetermined lengths, sealing the overlying layers at one end of each severed length, and cutting an opening in the wall of the tubular material suitable for receiving an inflation valve. The method includes severing preselected lengths of tubular bag material from a supply thereof, sealing one end of each length, and cutting an opening through the bag wall to receive an inflation valve.

Abstract: An end construction for forming a pinch closure over the opening in an end of a multi-ply, tubular bag, which includes a stepped and angle-cut flap on the portion of each ply on one side of the opening in the end of the bag, and a stepped and angle-cut cut-out in the portion of each ply on the other side of the opening in the end of the bag, the flap on each ply being adapted to fold about a fold line, located inwardly of the opening, to overlap the leading edge of the cut-out in the ply. The pinch closure is formed from the end construction by the steps of folding the flap on each ply about the fold line, over the opening in the end of the bag and over the stepped and angle-cut cut-out in the ply, and adhesively bonding the flap to the underlying portions of the ply in the area of the leading edge of the stepped and angle-cut cut-out in the ply.