US3497130A - Plastic bag - Google Patents

Description

7 R. STAHL Feb. 24, 1970 PLASTIC BAG Filed July 5, 1968 w :H R .8 m M S M m L T R E B OY RB United States Patent 3,497,130 PLASTIC BAG Robert L. Stahl, Wilmette, Ill., assignor to Plastic Packaging Company, Wheeling, 111., a corporation of Illinois Filed July 5, 1968, Ser. No. 742,709 Int. Cl. B65d 33/06 US. Cl. 229-54 2 Claims ABSTRACT OF THE DISCLOSURE A tote type of flexible plastic bag (of polyethylene sheeting), wherein the top and bottom is gussetted, the top gusset being slit at its inner margin to provide access, and with the top gusset also being apertured for the provision of angularly related, spaced apart finger insertion openings.

Background and summary of invention A large number of plastic bags are used each year. They come particularly at exhibitions, Where exhibitors give away merchandise, souvenirs, etc. Plastic bags are also employed by various stores for carrying phonograph records, sweaters and many other sundry items. Such packaging must meet two requirements. First it must be inexpensive, and secondly it must be relatively strong, i.e., sufliciently resistive to rupturing forces as to perform the intended function. These have been conflicting objectivesparticular1y insofar as the provision of handle grips are concerned.

Through the provision of a unique geometric construction adjacent the top portion of the flexible bag, I have solved this dilemma, and the provision of such a bag and the method of manufacture of the same constitute important objectives of the invention. More particularly, I find that by gussetting the top portion of the bag and providing spaced finger insertion openings (separated by an isthmus-like portion), I not only meet the requirement of inexpensiveness of manufacture, but also meet the requirement of suitable strength in and about the area most likely to rupture.

The invention is explained in conjunction with an illustrative embodiment in the accompanying drawing, in which- FIG. 1 is a perspective view of a bag constructed according to the teachings of the instant invention; and

FIG. 2 is a schematic view of a procedure for manufacturing the bag of FIG. 1, employing certain schematically depicted machine elements. 1

In the illustration given and in reference to FIG. 1, the numeral designates generally the inventive bag Which is seen to be essentially envelope-like. In that, I refer to the fact that it is generally rectangular, and has the capability of laying-flat. The bag 10 is seen to include a front panel 11 and a back panel 12. In reality no distinction is made between the front and back panels insofar as structure is concerned, although it is contemplated that at least one of the panels will be printed, thereby constituting a front panel. It will be appreciated, however, that both panels may be treated equally.

Continuing with the structural description of the envelope-like bag 10, the vertical edges 13 and 14 are united as by lineal heat seals, while the top and bottom portions are gussetted, as at 15 and 16. The upper gusset 15 is slit or cut at its lower or inner margin, as at 17, and the four thicknesses of polyethylene or like thermoplastic material in the area of gusset 15 are punched to provide finger openings 18 and 19, separated by an isthmus-like or neck portion 20.

The fuller appreciation of the structure may be obtained by a consideration of FIG. 2 which illustrates a manufacturing technique. Referring to the extreme lefthand portion of FIG. 2, it is seen that a tube 21 is provided, which has developed on opposite sides thereof, the gussets 1-5 and 16. In the illustration given, a bag having a lay-flat transverse dimension of the order of 14 inches is provided with each of the gussets 15 and 16 being three inches wide. Optimally, the thicknesses of the gussets arranges between about 15% to about 30% of the width of the flat tube 21. Following the development of the gussets 15 and 16 in the flat tube 21, the tube is subjected to compression, which is achievable readily by compression rolls (not shown) in the area designated 22 in FIG. 2. Thereafter a punching operation as at 23 is performed to develop the finger slots 18 and 19. Subsequent to this operation, the inner margin 17 of gusset 15 is slit; this being illustrated schematically by means of the knife 24. Thereafter, the bag is completed by heat sealing and cutting simultaneously by means of bars 25 and 26, suitably electrically powered, as indicated at 27 and 28, to unite opposite walls of the tube along lines transverse of the length of the tube 21. In some instances, I find it advantageous to simultaneously punch a plurality of superposed bags after they have been otherwise completed in accordance with the foregoing sealing and cutting.

In the illustration given, the bag has lay-flat dimensions of about 12 inches measured between the side seals 13 and 14 and a height of about 14 inches. As mentioned previously, the upper gusset may have a width on the order of 3 inches and I find it advantageous to provide finger slots of the configuration shown. This configuration is generally obround, with the end portions, for example, being developed by radii of the order of A2 inch, interconnected by straight sections of a length of about 1 /8 inches. The adjacent portions of the two openings or slots 18 and 19 are sufiiciently spaced to provide the isthmus of 20 of a minimum width of the order of /2 inch. Also, the minimum spacing of the nearest portion of each opening from the extreme top 29 as well as the inner margin 17 is about Vs inch-thereby assuring a suitable width of four thicknesses of film to provide a rupture-resistive structure.

Also, in some instances, I can eleminate the bottom gusset. However, the bottom gusset is advantageous in providing a readily achieved third dimension-creating more space within the bag. Also, the provision of the two gussets balances the formed tube for various processing operations, particularly printing.

I claim:

1. A flexible plastic bag comprising a unitary, generally rectangular envelope, having front and back Panels and thermoplastic sheeting, said sheeting being united along opposite sides by linear heat seals, said envelope having a gusset at least at the top thereof, with the top gusset being slit to afford access to the interior, and a pair of laerally spaced apart finger insertion openings extending through said panels in the top gusset portion, said openings defining an isthmus-like portion therebetween consisting of four thicknesses of sheeting to reinforce said envelope against rupturing stresses about said openings, said openings being generally obround with the longer dimensions of said obround openings being downwardly convergent.

2. A flexible plastic bag comprising a unitary generally rectangular envelope, having front and back panels and thermoplastic sheeting, said sheeting being united along opposite sides by linear heat seals, said envelope having gussets at the top and bottom thereof with each gusset constituting about 15% to about 30% of the height of the envelope, the top gusset being slit to alford access to the interior, and a pair of laterally spaced apart finger insertion openings extending through said panels in the top gusset portion, said openings defining an isthmus-like portion therebetween consisting of four thicknesses of sheeting to reinforce said envelope against rupturing stresses about said openings, said openings being generally obround with the longer dimensions of said obround openings being downwardly convergent.

References Cited UNITED STATES PATENTS 2,283,069 5/1942 Knuetter 22953 3,282,493 11/1966 Karnins et al. 22954 3,402,749 9/1968 Kinzler 22954 X DAVID M. BOCKENEK, Primary Examiner US. Cl. X.R.

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