US 3670953 A
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 three superimposed panels provided by longitudinal fold lines. 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 (OCR text may contain errors)
United States Patent Leventhal 1 51 June 20, 1972 BAG 2,969,101 H1961 White ..229 57 x  Inventor: Howard L. Levemhal Baton Rouge, La. 3,349,991 10/1967 Kessler ..229/57 X  Assignee: Ethyl Corporation, New York, NY. Primary Examiner-Donald F. Norton [221 Filed: 10 1970 Att0rney-Donald L. Johnson, John F. Sieberth, E. Donald Mays and Arthur G. Connolly  Appl. No.: 96,854
 ABSTRACT  U.S. Cl ..229/57 A container d f thi -wall, flexible, gusseted, tubing [5 l l "365d 33/00 material that opens into a bag having a rounded, generally flat,  Fleld of Search ..229/53, 55, 57, 58; l50/l high strength boner The bag when folded fl fQr packa d 1 g ing, has three superimpose pane s provided by longitudinal  References cued fold lines. The panels include a pair of outer plies and a pair of UNITED STATES PATENTS inner plies. One end of the bag is heat sealed to provide a bottom closure for the bag. 2,819,834 1/1958 Brady ..229/57 UX 2,915,098 12/1959 McKay ..229/57UX 4 Claims, 4 Drawing Figures PATENTEBJum 1212 3,670,953
SHEET 20F 2 BAG BACKGROUND OF THE INVENTION 1. 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, trash, and lawn and leaf 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., 20-30 gallon 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 lO-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., U.S. Pat. Nos. 2,819,834; 3,263,901; and 3,349,991, 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, foldahle 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 readil y 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.
Still further object of the present invention isto 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 three 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 inner panel has two continuous outer plies and two pairs of discontinuous inner plies. 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. l 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. I;
FIG. 3 is an enlarged sectional view taken along the line 3- 3 of FIG. I; 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 includes a front panel, designated generally by the numeral 11; a center panel, designated generally by the numeral 12; and a rear or back panel, designated generally by the numeral 13. Each panel is composed of a multiplicity of plies and is formed by making an accordian fold along two longitudinal fold lines spaced inwardly to divide the pregusseted tubing into three equal panels. The front panel is provided with a front outer ply l4 and a rear outer ply 15. Received between the outer plies I4 and I5 are superimposed, interconnected inner plies l6 and 17. The inner ply I6 is joined to outer ply 14 along fold line 18. In a like manner rear ply I5 is joined to adjacent inner ply I7 along longitudinal fold line 19. The inner or center panel. designated generally by the numeral 12, includes opposed. flat. outer plies 20 and 21. The front outer ply 20 of the center panel is connected through fold line 22 to the rear outer ply 15 of the front panel. Outer ply 14 of the front panel is connectedto the rear outer ply of the inner panel by means of fold line 23. The innerpanel 12 includes a first pair of superimposed inner walls and which project approximately half-way across the width of the inner panel. The walls 164 and 17a are joined by fold lines to the respective inner walls 16 and 17 of outer ply II and form the bottom of the deep gusset. Fold line 24 joins the pair of inner walls 16a and 17a at their terminal ends. Ply I7 is joined to ply I7a by means of fold line 25, and ply I is joined to ply 16a by means of fold line 26. The back panel of the bag 13 includes a front outer ply 27, a rear outer ply 28, and two superimposed inner plies 29 and 30. Plies 27 and 29 are joined by longitudinally extending fold line 31, and plies 28 and 30 are joined along one edge by longitudinal fold line 32. Ply 29 is joined by fold line 33 to inner ply 29a which forms a part of center panel 12. Inner ply 30 is joined by fold line 34 to inner ply 38 of inner panel 12. The two center plies 29a and 30a are joined by inner, longitudinally extending fold line 35 and form a second pair of inner walls opposite of and separate from the first pair of inner walls 16a and 17a. Thus, it is seen that the separate inner layers of the inner or center panel are fonned from the deep gusseted end portions of plies 29a and 30a and also plies 16a and 17a. While the longitudinal fold lines 24 and 35 of these plies are shown as spaced apart, it
is understood that they may be in abutting relationship if desired.
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 two longitudinally extending folds in the flattened, gusseted tubing to produce the folded construction as seen in FIGS. 1 and 2 wherein the bag is provided with the three panels ll, 12 and 13. The folded tubing is then passed to a traveling heater bar wherein a heat seal 36 is made transversely across the triple-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. 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-fifth 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 37 and 38. 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 tubing material the combination comprising in the flat, folded state:
a. three substantially equal width, superimposed, interconnected panels,
i. the two outer panels each having four plies of material,
the inner two plies of which are sections of a gusset,
ii. the inner panel having two continuous outer plies and two pairs of discontinuous inner plies;
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 pairs of discontinuous inner plies are formed by the terminal ends of said gussets.
3. In the container of claim 2 wherein said terminal ends of said gussets are spaced apart.
4. In the container of claim 1 wherein said outer plies of each of said outer panels are connected to said outer plies of said inner panel along opposite side edges thereof.