Grocery sack process and machine
AssigneeNational Petro Chemicals Corporation
InventorsHerbert Brock, Glenroy G. Blatz, James B. Honn
Life of this patent
Estimating the term…
Abstract
Apparatus and process for continuously and repetitively producing grocery sacks from a thermoplastic web at high speed, including particularly a folding operation involving applying grasping action to bag blanks formed from a heat sealed gusseted flattened tubular web of, e.g., high density polyethylene at the upper and lower portions thereof, respectively, causing said portions to be forwarded at differential longitudinal speeds whereby a rough folded bag bottom is formed. Preferably, the web is flexed as by introduction of air to the bag blank or sack to release the respective web faces and facilitate folding. A complete apparatus includes sealing, cutting, folding and pressing means and may incorporate printing and like ancillary features.
Claims21
In an apparatus for forming bags from a tubular web of plastic material having gussets formed from a centrally inlaid portion of said web at each lateral terminus thereof including means for transporting said web in a plane common to the lower gusseted portion thereof, means for sealing and cutting said web into predetermined lengths sealed at one end thereof and means for forming the bag base, the improvement comprising first and second gripper means for gripping the lower and upper gusseted portions of said web respectively, the first gripper being engageable with the lower gusseted portion of the web at a distance from the sealed end thereof approximately equal to the gusset depth and the second gripper means being engageable with the upper gusseted portion adjacent the sealed end within said distance;
- first and second conveying means for carrying said first and second gripper means, said first and second gripper means traveling in the same direction as said web, one of said gripper means traveling at the same speed as the web, and the other gripper means at slower speed so that the bag bottom is roughly formed and folded whereupon the slower speed gripper means are released.
In a process for forming bags with folded bottoms therein from a gusseted flattened tubular web of thermoplastic material wherein said web is fed through a zone in which it is transversely sealed at spaced locations and severed adjacent the sealed portions to form a series of longitudinally disposed bag blanks, one extremity thereof being sealed, and a bag bottom formed from said sealed bag extremity, the improvement which comprises separately engaging the upper and lower gusset portions of the web at spaced points on each side of the web adjacent the sealed extremity thereof, causing the upper and lower gusset portions to move at a differential longitudinal speed relative to one another in the same direction so as to form directly a roughly folded bottom therein, and releasing the bag, whereby such process may be continuously and repetitively operated at high speed to produce a multiplicity of bags sequentially.
A process for forming a bag with a folded bottom comprising providing a bag blank being a discrete segment of a gusseted flattened tubular web of thermoplastic material having one end transversely sealed at a folding station;
- releasably grasping the upper and lower gusset portions of the bag blank at spaced points on each side of the bag blank adjacent the sealed end thereof while forwarding said bag blank through said folding station, said upper gusset portions of each side of said bag blank being commonly forwarded in the same direction at a speed different from that of said lower gusset portions causing lateral folds to form in each face of said bag blank and the gusset portions adjacent the grasping region defining a bag bottom.
A process for forming a bag with a folded bottom comprising:
- providing a web of flattened tubular thermoplastic material having top and bottom faces united along each longitudinal edge by an inlaid folded gusset;
- sealing said web transversely at spaced locations;
- severing said web adjacent and forwardly of the sealed portions to form a series of discrete bag blanks, the leading extremity thereof being sealed;
- releasably grasping the bottom portion of each edge of each of said bag blanks, sequentially, at common points a distance from the sealed extremity approximately equal to the gusset depth and transporting said bag blanks thereby into a folding zone at a first speed;
- releasably grasping the upper portion of each edge of each of said bag blanks, sequentially, at common points directly adjacent the sealed end thereof, and forwarding said upper portion of said bag blanks at a second speed slower than said first speed, whereby rough transverse folds are caused to form in each face of said bag blank and the gusset portions adjacent the grasping region defining a rough bag bottom therein;
- releasing said upper portion of each of said blanks, respectively;
- transporting roughly folded bag blanks sequentially to a pressing station;
- and
- pressing said bag blanks respectively.
A process of automatically and continuously making folded bottom gusseted grocery sacks at high speed from a travelling web of gusseted thermoplastic film, the process comprising:
- a. controllably feeding the web to a sealing zone;
- b. continuously sealing the moving web across the width of the web while heating it, the speed of the moving web during sealing being slightly less than the feeding speed so the seals are not torn apart;
- c. cutting the web transversely in synchronism with and adjacent the seals to create individual sacks;
- d. moving the individual sacks at the speed of the web though airing opening, bottom folding, and deairing zones;
- e. blowing a controlled amount of air into the individual sacks as they move through the airing zone to open the sacks;
- f. folding the bottom of the individual sacks as they move through the folding zone by gripping the upper side of the sack gusset and moving it at a slower speed from the bottom sack gusset;
- g. removing the air from the individual rough folded bottom sacks as they move through the deairing zone;
- h. taking away the individual folded bottom sacks from the deairing zone and simultaneously pressing the fold therein.
Dependencies are inferred from the claim text.