Method for manufacturing a square bottom bag

A method for forming a square bottom bag from a web of bag forming material which is longitudinally elongated in a first direction and has a main panel extending in said first direction bounded on either side by a side closure forming portion comprising the steps of:

• (a) driving said web in said first direction into a bag forming station and bending a first bag forming length of said web transversely upon itself as it is driven into said forming station to an open U-shaped configuration in which portions of said main panel are disposed opposites and are spaced from one another in the configuration which they will assume when said bag is open;
• (b) supporting said main panel in said open U-shaped configuration;
• (c) severing said first bag forming length from said web;
• (d) folding said side closure forming panels toward one another to an overlapping relationship and securing said side closure panels with respect to one another in said overlapping relationship to form side walls of a bag;
• and
• (e) discharging the thus formed bag from said forming station in an open configuration.

A method of forming a square bottom bag from a bag forming section of a web of bag forming material which has a length in a first direction and a width in a second direction at right angles to said first direction and which includes a main panel extending in said first direction having front, bottom, and back wall forming portions serially connected to one another and side closure forming panels extending laterally from said front, bottom and back forming portions, comprising the steps of;

• (a) bending said web upon itself across its width to an open U-shaped configuration in which the front and back wall forming portions of the main panel are spaced from one another by the bottom wall forming portion,
• (b) supporting said front, bottom and back wall portions on a stationary mandrel in said open U-shaped configuration,
• (c) folding the side closure forming panels extending from the front and back portions of the main panel inwardly toward one another to an overlapping relationship and thereafter folding the side closure forming panels projecting from the bottom wall inwardly of the mandrel to outwardly overly the said closure forming panels of the front and back wall and securing said side closure forming panels in said overlying relationship to close opposite sides of the bag, and
• (d) discharging the thus formed empty bag from the mandrel in an open configuration.

A method of forming a square bottom bag from a bag forming section of a web of bag forming material which has a length in a first direction and a width in a second direction at right angles to said first direction and which includes a main panel extending in said first direction and bounded on either side by a side closure forming panel comprising the steps of:

• (a) driving said web in said first direction and bending said web upon itself across its width, as it is driven in said first direction to an open U-shaped configuration in which said main panel forms unitary, serially connected, front, bottom and back walls which are closed in the configuration which they will assume when said bag is open,
• (b) supporting said main panel in said open U-shaped configuration,
• (c) folding said side closure forming panels toward one another to an overlapping relationship and securing said side closure forming panels with respect to one another in said overlapping relationship to form side walls of a bag,
• (d) said side closure forming panels including first panels projecting laterally from said front and back walls of said main panel and second panels projecting laterally from said bottom wall, said first panels being folded inwardly as aforesaid to said overlapping relationship and thereafter said second panels being folded inwardly to be secured in an outwardly overlying relationship with respect to their associated first panels, each of said second panels being cut along a pair of spaced cut lines extending inwardly from the side edges of the web centrally of the length of each second panel to form a pad therebetween whereby upon folding of said first panels inwardly as aforesaid said second panels are folded along a fold line extending diagonally between the base of each of said cut lines and an adjacent corner of said bottom panel.