Patent ID: 6609998
Filing Date: 2003-08-26
Classification: B31B

Abstract:
A method of making a plastic film bag with opposed closable end openings, said method comprising the steps of:i) drawing a prefolded film sheet through a gusset forming station, said prefolded film sheet having opposed film panels, an open edge and an opposed closed parallel edge, ii) folding said closed parallel edge through a gusset former to form an offset gusset end, said gusset former having a lower and an upper film positioner provided with guide edges, an intermediate film positioner between said lower and upper film positioner, one of said guide edges being offset in a vertical plane from the other guide edge whereby to form a double offset folded closed edge to define an outer folded edge and an inwardly spaced folded edge interconnected through an intermediate inwardly spaced folded film section, iii) serrating a tear line adjacent said outer folded edge, iv) drawing said outer folded edge through a zipper applicator to heat fuse a plastic zipper section on said panels along said outer folded edge inwardly of said tear line towards said inwardly spaced folded edge, and v) feeding said prefolded film sheet with said offset gusset end and with said zipper and tear line through a bag former where said prefolded film sheet is transversely slit and edge sealed to form plastic bags with a closable open end and an opposed gusseted zippered end.