Plastic film bag manufacturing apparatus and associated methods, and plastic film bags produced thereby

A method of fabricating a bag from a thin thermoplastic tube in which the bottom of the bag is formed by a transverse heat seal and the top of the bag is openable by separating the tube, the bag having one end of an elongated tie element attached to one edge of the bag with the other end of the tie element free, to be wrapped around the neck of the bag to close the open end, comprising the steps of:

• continuously extruding a thin film bag tube of the thermoplastic material and flattening the tube into a bag web having opposite side edges;
• sequentially forming a series of transverse heat seals at spaced intervals along the tube to form the bottoms of the respective bags, while moving the bag web along a line;
• simultaneously moving a thin film tie element web along a controlled path to a heat welding element positioned at one edge of the bag web, while cutting short lengths transversely from the end of the tie element web to form successive elongated tie elements,
• heat welding each tie element to the edge of each bag at a point spaced from the transverse heat seal, and
• at least partially separating the bag web between the tie element and the transverse heat seal to permit the individual bags to be separated and form the open top of the bags.

A method of fabricating a bag from a thin thermoplastic tube in which the bottom of the bag is formed by a transverse heat seal and the top of the bag is openable by separating the tube, the bag having one end of an elongated tie element attached to one edge of the bag with the other end of the tie element free, to be wrapped around the neck of the bag to close the open end, comprising the steps of:

• continuously extruding a thin film bag tube of the thermoplastic material and flattening the tube into a bag web having opposite side edges;
• sequentially forming a series of transverse heat seals at spaced intervals along the tube to form the bottoms of the respective bags, while moving the bag web along a line;
• simultaneously moving a thin tubular flattened double layered film tie element web along a controlled path to a heat welding element positioned at one edge of the bag web, while cutting short lengths transversely from the end of the tie element web to form an elongated tie element,
• heat welding both layers of each tie element to both layers of the edge of each bag at a point spaced from the transverse heat seal, and
• at least partially separating the bag web between the tie element and the transverse heat seal to permit the individual bags to be separated and form the open top of the bags.

A method of fabricating a bag from a thin thermoplastic tube in which the bottom of the bag is formed by a transverse heat seal and the top of the bag is openable by separating the tube, the bag having one end of an elongated tie element attached to one edge of the bag with the other end of the tie element free, to be wrapped around the neck of the bag to close the open end, comprising the steps of:

• continuously extruding a thin film bag tube of the thermoplastic material, forming a gusset in one edge of the tube to form a four layered section along one side and flattening the tube into a bag web having opposite side edges;
• sequentially forming a series of transverse heat seals at spaced intervals along the tube to form the bottoms of the respective bags, while moving the bag web along a line;
• simultaneously moving a thin film tie element web along a controlled path to a heat welding element positioned at one edge of the bag web, while cutting short lengths transversely from the end of the tie element web to form an elongated tie element,
• heat welding each tie element to all four layers of the edge of each bag at a point spaced from the transverse heat seal, and
• at least partially separating the bag web between the tie element and the transverse heat seal to permit the individual bags to be separated and form the open top of the bags.

A method of forming elongated flexible bag tie elements and operatively securing them to individual bag portions defined on a longitudinally moving plastic film bag web having a side edge portion projecting outwardly from the balance of the moving bag web, said method comprising the steps of:

• longitudinally moving a plastic film tie element web having two plastic film layers along a controlled path;
• sequentially severing successive longitudinal segments from the moving tie element web to form a series of elongated flexible bag tie elements;
• transversely conveying each of the tie elements to a position in which it longitudinally extends transversely across an exterior side surface portion of the bag web with an inner end portion of the tie element overlying said side edge portion of the bag web;
• and
• heat sealing the inner ends of the tie elements to said side edge portion of the bag web at longitudinally spaced locations thereon.