Abstract: There is provided a method and an apparatus for forming the tops of material-filled bags into substantially fin-like shapes suitable for sealing in conventional top-sealing machines. The filled bags may be conveyed at random to a top-forming location in the apparatus where a bag is stopped, a device such as a pair of hinged plates is inserted into the top of the bag, front and back forming plates and side gusseting blades simultaneously engage the outside of the bag, forming the top into a fin-shape, the blades and plates are withdrawn, and the bag is then conveyed from the top-forming location. Bag tops are formed more consistently and with excess air expelled with the present method and apparatus.

Abstract: A slitter mechanism for use in a double fold bottomer apparatus employed in making bags from starting flush cut tubes is described which gives precise, high speed side marginal tube slitting in order to permit subsequent downstream gluing and folding operations. In preferred forms, the slitter mechanism includes a bag-end separating assembly having a vacuum manifold and a cooperating adjacent deflector bar serving to separate end portions of the sidewalls of a moving tube. A sequentially rotatable blade is also provided which first enters the open end of the moving tube between separated wall portions, overtakes and slits the leading side margin of the tube, and then stops with a trailing slitting edge situated within the tube open end; subsequent bag movement causes the trailing tube side margin to engage and be slit by the stationary blade edge.

Abstract: An improved bag construction, and a method of bag forming, are disclosed which gives an economical yet strong, burst- and leak-resistant closure without the necessity of sewing or use of expensive stepped cut tubes. The bag is formed using a tube having opposed, interconnected front and rear panels, wherein a pair of laterally spaced, parallel cut lines are provided adjacent the top margin of the tube which define opposed first and second marginal flaps respectively in the front and rear panels. In bag-forming operations, the first flap is folded and glued against the outer face of the front panel, and the closure is completed by folding and gluing the second flap over the open end of the tube in a manner to refold the first flap and engage the outer face of the first panel. In another embodiment, a filling valve is inserted between the front and rear panels adjacent the closure end during the bag-forming operation, so as to provide a valve bag.

Abstract: An apparatus and method for handling, separating and feeding gusset tubes from stacks thereof is provided which allows continuous, high speed separation and feeding of individual tubes without sagging or hangup problems, and at high operational speeds. The apparatus includes a pickup and feeding mechanism having tube-engaging arms, vacuum tube grippers for positively forming a bowed section in the tubes as they are lifted and upright stop structure for preventing shifting movement of the tube stack at the pickup station and separating any underlying tubes which may adhere to the topmost tube being fed. Stack elevating and lowering apparatus includes electrically controlled lifting mechanism having a pair of interconnected clutch elements for control of vertical movement. A conveying assembly having incrementally driven stack-supporting belts and pusher arms shiftable at a speed different than the belts serves to feed successive stacks to the pickup and feeding mechanism.

Abstract: Apparatus for automatically inserting plastic liners in open-mouth multiwall paper bags having means for holding a stack of the bags to be lined, and means for opening the uppermost bag of the stack for insertion of a liner therein. Insertion is via an inserter having vacuum means for gripping a liner, the inserter moving forward into the opened bag at the top of the stack for inserting a liner grasped by the inserter into the bag. The inserter moves the lined bag forward to an outfeed position where an outfeed means engages the lined bag to feed it forward for being stacked and, with the grip on the liner released, the inserter is retracted for the next cycle of operation. Liners are supplied from a roll in which they are interconnected end-to-end in series at transverse lines of weakness, the leading liner of the series being torn off and fed into position for being gripped by the vacuum means of the inserter.