US3317117A

US3317117A - Bag

Info

Publication number: US3317117A
Application number: US441211A
Authority: US
Inventors: Ralph C Goodwin
Original assignee: Bemis Co Inc
Current assignee: Amcor Flexibles North America Inc
Priority date: 1965-03-19
Filing date: 1965-03-19
Publication date: 1967-05-02
Anticipated expiration: 1984-05-02

Description

y 1 7 11. GOODWIN 3,317,111

BAG

5 Sheets-Sheet 1 Filed March 19, 1965 y 2, 1967 R. c. GOODWIN 3,317,117

BAG

5 Sheets-Sheet 2 Filed March 19, 1965 Filed March 19, 1965 M y 1957 R. c. GOODWIN BAG 3 Sheets-Sheet 3 United States Patent 3,317,117 BAG This invention relates to bags, and more particularly to bags made of flexible heat-sealable sheet plastic material such as polyethylene.

Among the several objects of the invention may be noted the provision of bags, and more particularly heavyduty polyethylene bags for containing material such as powered or granular material, having an improved strong sift-proof end closure construction; the provision of a bag such as described which may be of the open-mouth type and as to which the bottom end closure is of such strong sift-proof construction and adapted to square off when the bag is filled, i.e., to assume a rectangular configuration; the provision of a bag such as described which may be of the valve type and as to which both the bottom and top end closures are of such construction and adapted to square off when the bag isfilled; and the provision of a bag such as described in which the end closure or end closures are made separately from the bag body of material of sufficient thickness for adequate strength of the end closure or closures and the body of the bag is made of thinner material so as to effect savings in the total poundage of material used. Other objects and features will be in part apparent and in part pointed out hereinafter.

The invention accordingly comprises the constructions hereinafter described, the scope of the invention being indicated in the following claims.

In the accompanying drawings, in which several of various possible embodiments of the invention are illustrated,

FIG. 1 is a perspective of an end closure used in making a bag in accordance with this invention;

FIG. 2 is a perspective of the FIG. 1 end closure in its ultimate folded condition for attachment to a bag body;

FIG. 3 is a plan of the end closure in its folded condition;

FIG. 4 is an elevation of the folded end closure;

FIG. 5 is an enlarged section taken on line 5-5 of FIG. 3;

FIG. 6 is a perspective, partially broken away, showing a bag tube to which the end closure of FIGS. 2-5 is attached;

FIG. 7 is a section on line 77 of FIG. 8;

FIG. 8 is a section on line 8-8 of FIG. 9;

FIG. 9 is a fragmentary elevation of a completed bag;

FIG. 10 isa fragmentary elevation showing-the bag in its ultimate condition with the end closure folded fiat against a wall of the bag;

FIG. 11 is a fragmentary perspective of a tube for making a bag in accordance with a modification of the invention;

FIG. 12 is a fragmentary section through a bag made from the FIG. 11 tube;

FIG. 13 is an enlarged section taken on line 13-13 of FIG. 12;

FIG. 14 is a view in elevation of a valve bag made in accordance with this invention; and

FIG. 15 is an enlarged section taken essentially on line 15-15 of FIG. 14 showing the valve.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

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Referring first to FIG. 1 of the drawings, there is indicated at 1 an end closure to be used in making a bag of this invention, the end closure being shown in a preliminary condition prior to being attached to a bag tube to form a bag. The end closure 1 is formed from a sheet of flexible heat-scalable sheet material such as polyethylene by well-known vacuum-forming technique to be of shallow rectangular box shape open at the top, having a flat rectangular bottom or base 3, rectangular side walls 5 and rectangular end Walls 7. The height of the side and end walls is somewhat greater than one-half the width of the base 3. As will be understood, the vacuum forming operation basically involves heating a sheet of the thermoplastic material (e.g., polyethylene) to a temperature suitable for vacuum forming it, applying the heated sheet to a mold of the desired rectangular prismatic shape, and forming the heated sheet to the shape of the mold by applying vacuum through suitable vacuum pas sages in the mold so that atmospheric pressure causes the sheet to become flattened or draped all around the mold and assume the rectangular prismatic shape of the mold. On cooling, the formed sheet retains the rectangular box shape shown in FIG. 1. The sheet used in making the molded end closure 1 is preferably a relatively heavy gauge sheet, being of the order of eight to ten thousandths of an inch in thickness, for example.

The molded end closure 1 is adapted to be attached to an end of a tube 9 (see FIG. 6) which constitutes the body of the resulting bag. The bag body or tube 9 shown in the drawings is made of flexible heat-scalable sheet plastic material such as polyethylene. Typically, it is segmented from a continuous length of flat longitudinally seamed tubing, the longitudinal seam appearing at 11 in FIG. 6. The material of the tube 9 may be of thinner gauge than the material of the end closure 1, having a thickness of five thousandths of an inch, for example. The tube 9, as shown in FIG. 6, has a stripe 13 of a heat-seal-inhibiting material extending completely girthwise around the tube on the inside face thereof at its lower end. The heat-seal-inhibiting material used at 13 may be, for example, a commercially available polyamide-base ink printed on the plastic material from which the tube is formed by suitable means.

The molded end closure 1 is formed for attachment to one end (the lower end) of the tube 9 by pinching the opposite side walls 5 of the end closure together to cause lower portions 15 thereof to fold over fiat on the bottom or base 3 of the end closure and to bring upper marginal portions 17 thereof into face-to-face relation extending centrally lengthwise of the bottom or base 3. In carrying out this operation, portions 15 are folded over on the bottom or base 3 on fold lines 19 which are the original lines of juncture of the side walls 5 and bottom or base 3, portions 17 are folded up on fold lines 21, portions 23 of the end walls 7 of the molded end closure 1 are folded over upon the bottom or base 3 on 45 fold lines 25, and portions 27 of the end walls stand up to form a continuation of the face-to-face portions 17 of the side walls. As a result of this operation, the molded end closure is formed to have a flat bottom or outer wall 29 (derived from bottom or base 3 and portions of the end walls 7) having a main narrow rectangular body portion bounded at the sides by lines 19 and triangular ends bounded by the 45 lines 25, panels 31 (each consisting of a portion 15 and triangular portions 23) folded over on lines 19 overlying the wall 29, and a flattened tubular lip 33 (constituted by portions 17 of the side walls 5 and portions 27 of the end walls 7) which stands up along the lengthwise center line of the closure.

The end closure 1, formed as shown in FIGS. '2-5, and the tube 9 shown in FIG. 6 are assembled to form the bag B shown in FIGS. 7-10 by inserting the lower end of the tube 9 into the tubular lip 33 (see particularly FIG. 8) between the opposed walls 17 of the tubular lip, and heat-sealing the walls of the tube 9 to the walls of the lip along lines of seal indicated at 35 extending throughout the width of the tube 9 (throughout the length of the lip). This operation is effected by applying heat and pressure in a single operation to opposite sides of the lip along the line of the heat seals, the interposition of the heat-seal-inhibiting material at 13 preventing heatsealing together of the Walls of the tube 9. It will be understood that the end closure 1 is molded with its dimensions such that when folded as shown in FIGS. 2-5, the length of the flattened tubular lip 33 is just slightly greater than the width of the tube 9 so that the lower end of the tube has a telescopic fit within the lip. The tube and the lip are therefore heat-sealed together throughout their peripheries in the area where they lap. Following the seat-sealing together of the end closure and the tube, the end closure may be folded over to the position shown in FIG. 10 to lie flat with the tube 9 (which consti tutes the body of the bag B).- As contemplated for the bag B, its upper end is left open so that it is an openmouth bag which, after filling, may be closed at the mouth in any suitable conventional manner.

The bag B, formed as above described, consists of the tube 9 and the separately formed molded end closure 1 having the tubular lip 33 lapping the lower end of the tube with heat seal 35 sealing together the tube and the lip completely around the lip. The walls of the bag are free of one another in the region of the heat seal 35 by reason of the interposition of the heat-seal-inhibiting material at 13 between the lower margins of the opposed walls of the flat tube 9. As noted, end closure 1 may be made of thicker sheet plastic material than tube 9. Thus, it constitutes a strong closure and, being formed in one piece, is sift proof. With closure 1 formed as shown in FIG. 10, it is adapted to square off, i.e., assume a rectangular configuration when the bag is filled. After filling, the bag may be sealed at the top in any suitable conventional manner.

FIGS. 11-13 illustrate a modification of the above, utilizing a tube 9a similar to the tube 9 except that the stripe 13 of heat-seal-inhibiting material is omitted, and utilizing an end closure 1a which is like the end closure 1 except that a stripe 13a of heat-seal-inhibiting material is provided on the inside face of lip 33. In this case, the lip 33 is inserted into the end of the tube 9a, after which the heat seal at 35 is made, the heat-seal-inhibiting material at 13a preventing heat-sealing together of the opposed faces of the lip.

The principles of the invention are applicable to valve bags, as well as open-mouth bags. FIGS. 14 and 15 illustrate a valve bag made in accordance with this invention comprising a tube 9 the same as above described and end closures 1 the same as above described sealed to the ends of the tube. One end closure (the top end closure as shown) prior to being sealed to the end of the tube has a transverse slit 41 cut in wall 29 thereof toward one end of wall 29 and extending from near one side 19 of wall 29 to near its other side. A valve flap 43 of flexible heat-scalable sheet plastic material underlies this slit, being heat-sealed at its outer end to wall 29 on a line 45 located immediately outward of the slit, and being heatsealed along its side margins to wall 29 on lines 47. Slit 41 constitutes an opening for insertion of a filling spout between wall 29 and the valve flap, the latter being free of wall 29 at its end remote from the slit for flow of material into the bag. After the bag has been filled and the spout withdrawn, the valve flap 43 closes the slit, as will be readily understood.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. A bag comprising a flat tube of flexible heat-sealable sheet plastic material, an end closure for one end of said tube formed from a one-piece molded body of flexible heat-sealable sheet plastic material of shallow rectangular box shape having a rectangular base, side walls and end walls, the height of the side and end walls being somewhat greater than one-half the width of the base, the side walls being folded over on the lines of juncture of the side walls and the base to overlie the base, marginal portions of the side and end walls being folded back on lines extending along the lengthwise center line of the base into face-to-face relation, the closure thereby having a fiat outer wall having a main rectangular body portion and triangular ends, panels folded over on said lines of juncture overlying said fiat outer wall, and a flattened tubular lip extending from the inner margins of said panels along the lengthwise center line of said outer wall from the apex of one of said triangular ends to the apex of the other, said lip lapping one end of said tube, and a heat seal sealing together the tube and the lip completely around the lip, the walls of the bag being free of one another in the region of the heat seal.

2. A bag as set forth in claim 1 having heat-seal-inhibiting material in the region of said heat seal precluding heat-sealing together of the walls of the bag at said seal.

3. A bag as set forth in claim 2 wherein the lip laps said one end of the tube on the outside thereof and the tube has said heat-seal-inhibiting material on the inside thereof in the region of said heat seal.

4. A bag as set forth in claim 2 wherein said one end of the tube laps the lip on the outside of the lip, and the lip has said heat-seal-inhibiting material on the inside thereof in the region of said heat seal.

5. A bag as set forth in claim 1 wherein said end closure is formed of thicker sheet plastic material than said tube.

6. A bag comprising a flat tube of flexible heat-sealable sheet material, end closures for the ends of said tube, each end closure being formed from a one-piece molded body of flexible heat-scalable sheet plastic material of shallow rectangular box shape having a rectangular base, side walls and end walls, the height of the side walls being somewhat greater than one-half the width of the base, the side walls being folded over on the lines of juncture of the side walls and the base to overlie the base, marginal portions of the side and end walls being folded back on lines extending along the lengthwise center line of the base into face-to-face relation, the closure thereby having a flat outer wall having a main rectangular body portion and triangular ends, panels folded over on said lines of juncture overlying said flat outer wall, and a flattened tubular lip extending from the inner margins of said panels along the lengthwise center line of said outer wall from the apex of one of said triangular ends to the apex of the other, the lip of each end closure lapping the respective end of the tube, and a heat seal at each end of the tube sealing together the tube and the lip of the respective end closure completely around the lip, the walls of the bag being free of one another in the region of the heat seals, one of said end closures being valved.

7. A bag as set forth in claim 6 having heat-seal-inhibiting material in the regions of the heat seals precluding heat-sealing together of the 'walls of the bag at said heat seals.

8. A bag as set forth in claim 6 wherein each end closure is formed of thicker sheet plastic than said tube.

9. A bag as set forth in claim 6 wherein said valved end closure has an opening in its said flat outer wall for 5 6 insertion of a filling spout and a valve flap of flexible heat- 3,006,257 10/ 1961 Orsini 9335 sealable sheet plastic material underlying said opening 3,073,507 1/ 1963 Trewella et a1. 22962 and heat-sealed to said valved end closure. 3,172,443 3/ 1965 Ausnit 150-3 3,237,534 3/1966 Lissner 93-35 References Cited by the Examiner 5 UNITED STATES PATENTS FOREIGN PATENTS 756,311 4/1904 Adams 229-57 481,189 2/1952 Canada- 1,127,2ss 2/1915 Johnston. 1,350,619 12/1963 France- 2,721,023 110/ 1955 Phipps 229-62 2823721 2/1958 Svec 10 JOSEPH R. LECLAIR, Przmary Exammer.

' 0 0 415 9 19 1 Gritcheuel- 15 3 D. T. MOORHEAD, Assistant Examiner.

Claims

1. A BAG COMPRISING A FLAT TUBE OF FLEXIBLE HEAT-SEALABLE SHEET PLASTIC MATERIAL, AN END CLOSURE FOR ONE END OF SAID TUBE FORMED FROM A ONE-PIECE MOLDED BODY OF FLEXIBLE HEAT-SEALABLE SHEET PLASTIC MATERIAL OF SHALLOW RECTANGULAR BOX SHAPE HAVING A RECTANGULAR BASE, SIDE WALLS AND END WALLS, THE HEIGHT OF THE SIDE AND END WALLS BEING SOMEWHAT GREATER THAN ONE-HALF THE WIDTH OF THE BASE, THE SIDE WALLS BEING FOLDED OVER ON THE LINES OF JUNCTURE OF THE SIDE WALLS AND THE BASE TO OVERLIE THE BASE, MARGINAL PORTIONS OF THE SIDE AND END WALLS BEING FOLDED BACK ON LINES EXTENDING ALONG THE LENGTHWISE CENTER LINE OF THE BASE INTO FACE-TO-FACE RELATION, THE CLOSURE THEREBY