US3670954A - Bag - Google Patents

Abstract

A container made from thin-wall, flexible, gusseted, tubing material that opens into a bag having a rounded, generally flat, high-strength bottom. The bag, when folded flat for packaging, has four superimposed panels connected by alternating longitudinal fold lines to provide a bag with Z or accordion folds. The panels include a pair of outer plies and a pair of inner plies. One end of the bag is heat sealed to provide a bottom closure for the bag.

Description

1 51 June 20, 1972 United States Patent Leventhal BAG 2,969,101 1/1961 White [72] lnventor: Howard L. Leventhal, Baton Rouge, La. 3349991 10,1967

Ethyl Corporation, New York, NY.

Dec. 10, 1970 Primary ExaminerDonald F. Norton [73] Assignee:

[22] Filed:

Atlomey-Donald L. Johnson, John F. Sieberth, E. Donald Mays and Arthur G. Connolly [21] A 1. No.: 96 855 pp ABSTRACT A container made from thin-wall, flexible, gusseted, tubing material that opens into a bag having a rounded, generally flat,

33/00 229/53 55, 57 58; 150 hlgh-strength bottom. The bag, when folded flat for packagm s... um 11 21 55 [1 mg, has four superimposed panels connected by alternating longitudinal fold lines to provide a bag with Z or accordion folds. The panels include a pair of outer plies and a pair of inner plies. One end of the bag is heat sealed to provide a bottom closure for the bag.

UNITED STATES PATENTS 2,819,834 l/l958 Brady................................229/57UX 2,915,098 12/1959 McKay..........................."1229/57UX 3Claims,4DrawingFigum PATENTEDJUHZO 1972 SHEET 18F 2 FIG. I.

BAG

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to bags, and more particularly to plastic bags, adapted to be fabricated by a high-speed, continuous manufacturing process. Particularly, the invention relates to polyethylene garbage, lawn and leaf and trash bags.

2. Description of the Prior Art Large plastic bags have been used heretofore as containers for material per se or as liners for cardboard and metal containers. The objective in the prior art has been to provide a bag with a bottom construction having high strength and good conformance with flat bottom containers. Recently, large-size, e.g., 1- to 3-bushel, plastic bags have come into widespread use as liners for garbage cans and as containers per se for garbage, trash, leaves, lawn rakings, etc., by both business establishments and home owners. In the production of such bags, it is preferred that a high-speed, rapid-folding construction be utilized in order to provide for the production and the packaging of bags at low cost. Additionally, one of the problems facing users of polyethylene garbage and trash bags has been to provide a bag with adequate bottom seal strength to prevent breakage in the heat seal area of the bag when fully loaded. The most common method of sealing garbage, leaf and trash bags is to use a transverse seal across a flattened tube, either gusseted or non-gusseted, and then fold the bag longitudinally and also transversely to allow a number of the bags to be placed into a container approximately 6- by 10-inch size for retail sale. This production requires first the heat sealing and then folding step which, thus, does not lend itself to rapid production. While some constructions for multiple-fold bags have been proposed in the prior art, e.g., US. Pat. Nos. 2,8 l9,834; 3,263,901; and 3,349,99l, none of these particular configurations has found wide acceptance in the market place. These patents disclose longitudinally folded plastic bags wherein a heat seal is applied through one end of the bag after the longitudinal folds are made. However, because of the folding configurations employed in each one of these patents, these types of bags are not readily produced by high-speed, inline, automated, bag-making and packaging machinery.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a flexiblewall, foldable container adapted to be manufactured and packaged on high-speed machinery.

It is another object of the present invention to provide a bag having a multiplicity of longitudinal folds which may be readily produced by mechanical means.

Still another object of the present invention is to provide a plastic bag having a bottom seal providing increased mechanical strength to the bag.

A still further object of the present invention is to provide a plastic bag that may be readily used as a container in itself or used as an inner liner for a rigid container.

The foregoing objects and other advantages are provided in a container of thin-wall, flexible, gusseted, tubing material which, in combination, includes in the flat, folded state four substantially equal width, superimposed, interconnected panels. Two outer panels are provided, each having four plies of material, the inner two plies of which are sections of a gusset. The two inner panels each have two continuous, non-connected outer plies and two inner plies connected together along one edge thereof. All of the panels and the plies are interconnected by a seal line across the container adjacent one end thereof.

Further objects and advantages will be apparent from the drawings and the following description.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational, perspective view of a bag made in conformance with this invention;

FIG. 2 is an enlarged sectional view taken along the line 2- 2 of FIG. 1;

FIG. 3 is an enlarged sectional view taken along the line 3 3 of FIG. 1; and

FIG. 4 is a bottom view of the bag of FIG. 1 in the fully opened position.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The bag of the present invention, designated generally by the numeral 10, may be made from any suitable material. If desired, the bag may be made from high-strength, very flexible paper and closed on the bottom by use of adhesives or a sew line. However, it is preferred that the bag of the present invention be made from a flexible, limp material such as plastic, in particular, polyethylene.

However, other plastic material such as polyvinyl chloride, polypropylene, polyvinylidene chloride, Saran, cellophane, nylon and Mylar may be used. It is understood that while the embodiment of the bag shown in the drawings utilizes a single sheet of plastic material, the bag of the present invention may be constructed from multilayer plastic materials, i.e., an outer layer of polyethylene and an inner layer of Saran, or any other combination desired. The bag as depicted in the drawings is made from a seamless section of plastic tubing; however, it is understood that the invention is not limited to such seamless tubing, but the bag may be readily constructed from flat sheets of materials which are lapped and longitudinally sealed by means of heat, adhesives, or other suitable means. Accordingly, the use of the term tubing herein is to mean the use of either seamless or seamed tubing.

A key aspect of the present invention is the utilization of pregusseted tubing for making the bag. By the utilization of tubing having deep gussets in each side, it is possible to provide a large diameter bag which may be folded a relatively small number of times to provide a bag width that can be conveniently boxed in sizes normally packaged for consumer use.

Referring now to FIGS. 1 and 2, it will be seen that the bag of the present invention, designated generally by the numeral 10, includes a front panel, designated generally by the numeral 11; a first inner or central panel, designated generally by the numeral 12; a second inner or central panel, designated generally by the numeral 13; and a rear or back panel, designated generally by the numeral 14. Each panel is composed of a multiplicity of plies and is formed by making an accordion fold along three longitudinal fold lines spaced inwardly to divide the pregusseted tubing into four equal panels. The front panel is provided with a front outer ply l5 and a rear outer ply 16. Received between the outer plies 15 and 16 are superimposed, interconnected inner plies l7 and 18. The inner ply 17 is joined to outer ply 15 along fold line 19. In a like manner rear ply 16 is joined to adjacent inner ply 18 along longitudinal fold line 20. The first inner or central panel 12 includes opposed, flat, outer plies 21 and 22. The front outer ply 21 of the first central panel is connected through fold line 23 to the rear outer ply 16 of the front panel. Outer ply 15 of the front panel is connected to the rear outer ply of the first inner panel 22 by means of fold line 24. The first inner panel 12 includes a first pair of superimposed inner plies 17a and 18a which project approximately across the full width of the first inner panel. The plies 17a and 18a are joined by fold lines to the respective inner plies 17 and 18 of outer ply 11 and form the bottom of a deep gusset. Fold line 25 joins the first pair of inner walls 17a and 18a at their terminal ends. Ply 17 is joined to ply 17a by means of fold line 26, and ply 18 is joined to ply by means of fold line 27.

The second inner or central panel 13 is provided with a front outer ply 28 and a rear outer ply 29. The front outer ply 28 of the second central panel is connected through fold line 30 to the rear outer ply 22 of the first inner panel. The rear outer ply 29 is connected by fold line 31 to the front outer ply 21 of the first inner panel. The second inner panel 13 includes a second pair of superimposed inner plies 35a and 36a which project approximately across the full width of the second inner panel. The plies 35a and 36a are joined by fold line 32. The other ends of plies 35a and 36a are joined by fold lines 37 and 38 to the respective inner plies 35 and 36 of the rear outer panel 14 and thus the plies 35 and 35a, together with plies 36 and 36a, form a deep gusset.

The back panel of the bag 14 includes a front outer ply 33, a rear outer ply 34, and two superimposed inner plies 35 and 36. Plies 33 and 35 are joined along one edge by longitudinally extending fold line 37, and plies 34 and 36 are joined along one edge by longitudinal fold line 38. Ply 33 is joined on its other edge by fold line 39 to the from outer ply 28 of the second center panel 13. Rear outer ply 34 is joined on its other edge by fold line40 to the rear outer ply 29 of the second inner panel 13. The two inner plies 35 and 36 are joined at their other ends by longitudinally extending fold lines 41 and 42, respectively, to inner plies 35a and 36a of the second inner panel 13.

- Thus, it is seen that the inner layers of both the first and second inner or center panels are formed from the terminal wall portions of the deep gussets provided in the flattened tubing and that the inner plies of the front and back panels are formed from the upper wall sections of the deep gussets.

The bag of the present invention is preferably produced by initially providing tubular plastic film from an annular die by means of the trapped bubble process and subsequently providing opposed deep gussets in the sides of the tube as it is flattened. The pregusseted tubing is next moved into folding boards or other type folding mechanisms which are well known in the art, such as that shown in previously mentioned US. Pat. No. 3,263,901, or the apparatus disclosed in US. Pat. No. 3,518,810. The folding or pleating apparatus is so constructed as to provide three equally spaced, longitudinally extending folds in the flattened, gusseted tubing to produce the Z or accordion folded construction as seen in FIGS. 1 and 2 wherein the bag is provided with the four panels 11, 12, 13 and 14. The folded tubing is then passed to a traveling heater bar wherein a heat seal 43 is made transversely across the folded bag whereby all plies and all panels are integrally fused together. If desired, a dual sealer bar may be used, i.e., one which applies heat from each side of the bag. Alternatively, radio frequency heating may be utilized whereby each of the plies is simultaneously fused to adjacent plies. Next, the intermittently sealed length of tubing is severed immediately below each seal line, whereby lengths of the bag of the desired length are produced.

The bag of the present invention is particularly adapted for utilization as a liner for a round container and produces an extremely strong, flat bottom. Referring to FIG. 4, it will be seen that when the bag is opened, the particular folding and sealing construction provided in the bag yields a bag having a bottom seal area approximately only one-eighth as wide as the diameter of the bag in its open state. Additionally, the particular fold configuration utilizes the deep V-shaped gussets to produce a bag having a large number of interconnected fold lines in the bottom of the bag whereby stress applied to the bottom of the bag is equally distributed over the entire bottom area. As noted in FIG. 4, the bottom of the bag is characterized by a multiplicity of interconnected folds arranged around the seal area and is characterized by two transversely extending fold areas 44 and 45. The bag of the present invention provides exceptional strength in the bottom area because of the even distribution of a multiplicity of folds which terminate in the generally hemispherically shaped bottom area.

While there has been described what is at present considered preferred embodiments of the present invention, it will be apparent to those skilled in the art that various modifications and changes may be made without departing from the essence of the invention. it is intended to cover herein all such modifications and changes as come within the true scope and spirit of the following claims.

What is claimed is:

1. In a container of thin-wall, flexible, gusseted, tubular material, the combination comprising in the flat, folded state:

a. four substantially equal width, superimposed, interconnected panels, 1. the two outer panels each having four plies of material,

the inner two plies of which are the outer sections of a gusset,

ii. the two inner panels each having two continuous, nonconnected outer plies and two inner plies connected together along one edge thereof;

b. all of said panels and plies being interconnected by a seal line across said container adjacent one end thereof.

2. In the container of claim 1 wherein said two inner plies are formed by the terminal ends of a gusset.

3. in the container of claim 1 wherein said outer plies of each of said outer panels are connected to said outer plies of the adjacent said inner panel along the same side edges thereof.

Claims (3)

1. In a container of thin-wall, flexible, gusseted, tubular material, the combination comprising in the flat, folded state: a. four substantially equal width, superimposed, interconnected panels, i. the two outer panels each having four plies of material, the inner two plies of which are the outer sections of a gusset, ii. the two inner panels each having two continuous, nonconnected outer plies and two inner plies connected together along one edge thereof; b. all of said panels and plies being interconnected by a seal line across said container adjacent one end thereof.

2. In the container of claim 1 wherein said two inner plies are formed by the terminal ends of a gusset.

3. In the container of claim 1 wherein said outer plies of each of said outer panels are connected to said outer plies of the adjacent said inner panel along the same side edges thereof.

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