US3409210A - Bag - Google Patents

Description

Nov. 5, 1968 A. R. BARRIS ET AL 3,409,210

BAG

5 Sheets-Sheet 1 Filed Aug. 23, 1967 Nov. 5, 1968 I A. R. BARRIS ET AL 3,409,210

BAG

Filed Aug. 23, 1967 5 Sheets-Sheet 2 Y \7 H6. 6 Y A A. R. BARRIS- ET AL I 3,409,210

Nov. 5, 1968 BAG 5 Sheets-Sheet Filed Aug. 23, 1967 A. R. amms' Erm. 3,409,210

BAG

v Nov. 5, 1968 5 Sheets-Sheet 4 Filed Aug. 23, 1967 Nov. 5 1968 A. R. amms ET AL BAG Filed Aug. 23. 1967 5 Sheets-Sheet 5 United States Patent 3,409,210 BAG Arthur R. Barris, West Chelmsford, and Edward V. Riehl, Littleton, Mass, assiguors to Bemis Company, Inc., Minneapolis, Minn., a corporation of Missouri Filed Aug. 23, 1967, Ser. No. 662,676 16 Claims. (Cl. 22955) ABSTRACT OF THE DISCLOSURE A two-ply SOS bag with a siftproof bottom in which the outside closure flap is formed with a tab on the inner ply portion thereof, this tab being folded in underneath the side sections of the bottom closure formation. The inner margins of the side sections of the closure formation overlap, and a slit is provided in both plies for the overlapping of these margins without bunching of the plies. An E-shaped paste pattern is provided for the pasting of the inside and outside closure flaps, the center stripe of this pattern being along the overlap of the side sections.

Background of the invention This invention relates to SOS bags, i.e., gusseted bags having a rectangular bottom, and particularly to such bags of two-ply construction. Such bags are conventionally made from a gusseted two-ply tube by folding back a portion of one wall of the tube on a transverse fold line to open up a bottom closure formation having a central rectangular area and first and second closure flaps at opposite sides of the central rectangular area, then folding the first closure flap over on and pasting it to the central rectangular area and folding the second closure flap over on and pasting it to the first closure flap. It has been contemplated to slit the inner ply to provide a tab on the second closure flap, but this, while desirable in certain respects, has been undesirable from the standpoint of providing points prone to sifting out of the contents of the bag (these bags being generally used for finely divided material). Such points occur, for example, where the slits intersect diagonal folds of the closure formation. Also, the provision of such a tab has interfered with the pasting of the second closure flap (the outside closure flap) when the inner ply is constituted by a material having polyethylene on its inside face, which renders pasting difiicult. It has also been contemplated to effect overlapping of the side sections of the bottom closure formation, but this has involved problems in pasting and due to bunching of the plies.

Summary of the invention Among the several objects of the invention may be noted the provision of an improved SOS bag which, while formed with inner ply slits defining a tab on the outside closure fiap, has this tab so disposed as to minimize sifting at the points above mentioned and, in the case of use of inner ply material having polyethylene on its inside face, so disposed as to allow paper-to-paper pasting, rather than polyethylene to paper pasting; the provision of such a bag in which the inner margins of the side sections of the bottom closure formation are overlapped without bunching; and the provision of such a bag with a paste pattern which effects siftproofing without excessive use of paste such as would render the bag bottom unduly stiif and cause difliculties in paste application and bottom formation.

In general, the above objects are attained by infolding of the tab defined by slits in the inner ply so that it lies underneath the side sections of the bottom closure formation, by providing a slit in both plies of the bag so located that, even though the inner margins of the side sections of the closure formation are overlapped, no bunching occurs, and by using a striped paste pattern rather than a solid pattern, including a stripe along the overlapping inner margins of the side sections. Other objects and features will be in part apparent and in part pointed out hereinafter.

Brief description of the drawings FIG. 1 is a view in elevation, broken away to reduce the height of the view, of one face of a bag tube from which a bag of this invention is made, and with a portion of the outer ply removed;

FIG. 2 is a view in elevation showing the other face of the bag tube, with a portion of the outer ply removed;

FIG. 3 is a View similar to FIG. 2 with another portion of the outer ply removed;

FIGS. 4 and 5 are transverse sections, with thicknesses exaggerated, on lines 4-4 and 5-5 of FIG. 3;

FIG. 6 is a section with thicknesses considerably exaggerated showing a laminated material with a polyethylene inside face such as may be used for the inner ply;

FIG. 7 is a view corresponding to FIG. 1 showing the opening up of the bottom closure formation;

FIG. 8 is a view of the lower part of FIG. 7, showing the tab infolded;

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

FIG. 10 is a view showing the paste pattern applied after the infolding of the tab; and

FIG. 11 is a view showing the completed bag.

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

Description of the preferred embodiment Referring to the drawings, FIGS. 1-5 illustrate a length of gusseted or intucked bag tubing 1 from which a bag of this invention is made. One of the opposed walls of this tube 1 is designated 3, and the other wall is designated 5. The gussets joining these walls at the sides of the tube are designated 7. The tube, as shown, is made of two-ply material, the outer ply being designated 9 and the inner ply being designated 11. The outer ply constitutes an outer tube and the inner ply constitutes a tubular liner nested in the outer tube. The outer ply is usually paper. For the inner ply there has been used laminated material comprising, in order from the outside layer to the inside layer, paper 11a, polyethylene 11]), aluminum foil 11c, and polyethylene 11d (see FIG. 6). The invention has certain specific advantages in regard to use of such laminated material, as will be subseqently described. However, it is contemplated that the invention is applicable to bags made of other materials, including plain paper for the inner ply.

At 13 (see FIG. 1) is indicated a fold line extending transversely across the wall 3 of the tube spaced from the bottom end of the tube a distance somewhat greater than half the width of the bottom to be formed. At 15 (see FIGS. 2 and 3) is indicated a corresponding fold line extending transversely across the other wall 5. Above line 13, there is indicated at 17 a fold line extending transversely across wall 3, spaced from line 13 a distance corresponding to the gusset width, on which the lower portion of wall 3 below line 17 is to'be folded back to provide a closure formation to be described. The tube may be prescored on line 17 to facilitate this operation. At 19 and 21 (FIG. 1) are indicated fold lines extending diagonally from the ends of line 13 at a 45 angle toward the bottom end of the tube in wall 3. At 23 and 25 (FIGS. 2 and 3) are indicated similar diagonal fold lines in wall 5. Lines 19 and 21 intersect at a point 27 in Wall 3 3 spaced above the bottom end of the tube, and lines 23 and 25 intersect at a corresponding point 29 in wall 5. Line 19 registers with line 25, and line 21 registers with line 23. Points 27 and 29 register with one another, and are located on the vertical center line of walls 3 and 5.

Wall 3 has a slit 31 in both the inner ply and outer ply extending upward from the bottom end of the tube. This slit is offset laterally from the vertical center line of wall 3 (offset to the right of the vertical center line as shown in FIG. 1), and it extends up to line 21. The edges of the plies at opposite sides of this slit are designated 31a and 31b.

Wall has a first pair of slits 33 and 35 in the outer ply only extending upward from the bottom end of th tube to lines 23 and adjacent the sides Of the tube, and a second pair of slits 37 and 39 in the inner ply only extending upward from the bottom end of the tube to lines 23 and 25 between slits 33 and on opposite sides of and adjacent the longitudinal (vertical) center line of the wall 5 and the tube. The rectangular portion of the outer ply between the slits 33 and 35 is designated 41. The portion of the inner ply between slits 37 and 39 constitutes a tab 43. The edges of the outer ply at opposite sides of slits 33 and 35 are designated 33a and 33b, 35a and 35b. The edges of the inner ply at opposite sides of slits 37 and 39 are designated 37a and 37b, 39a and 39b.

It will be understood that tubes 1 may be made in accordance with usual bag manufacturing practice, utilizing a conventional tuber, by combining a web of the material for the inner ply with a web of the material for the outer ply, forming the combined webs into continuous tubing with transverse lines of perforations spaced at bag length intervals, segmenting the tubing into individual tubes 1 by tearing it apart on the lines of perforations. As a result, the top and bottom edges of the tubes are serrated, as indicated at and 47, and have torn fibers projecting therefrom. The slits 37 and 39 are cut in the inner ply web and the slits 33 and 35 are cut in the outer ply web before the webs are combined; the slits 31 are cut in thetwo webs after they are combined. Also, paste is applied to the inner ply web before the webs are combined for inter-ply pasting in a pattern to be described.

As shown in FIG. 7, the lower portion of the wall 3 below line 17 is folded back on line 17 to provide a bottom closure formation which has two side sections 49 and 51 and which includes a central rectangular area 53 bounded by lines 13 and 15 and end folds at 55 and 57, a first closure flap 59 at one edge (the edge defined by line 13) of this central rectangular area and a second closure flap 61 at the opposite edge (the edge defined by line 15) of this central rectangular area. The first closure flap 59 is generally of triangular shape, having line 13 as its base and lines 19 and 21 as its sides. The second closure flap 61 includes a portion 63 derived from the outer ply which is in the form of an isosceles trapezoid, having line 15 as its base, and edges 33a and 35b of the outer ply resulting from the provision of slits 33 and 35 as its side opposite the base, and portions of fold lines 23 and 25 as its ends. Extending from this trapezoidal portion of the outer ply in flap 61 is the rectangular portion or tongue 41 of the outer ply. Flap 61 also includes a portion 65 derived from the inner ply which is in the form of an isosceles trapezoid, having line 15 as its base, and of greater altitude than trapezoidal portion 63 of the outer ply, projecting out beyond the edge 33a, 35b of portion 63 and having tab 43 (defined by slits 37 and 39). at its apex. This tab 43 lies on the inside face of rectangular portion 41 of the outer ply.

Each of the side sections 49 and 51 of the bottom closure formation has a width in the central area 53 somewhat greater than half the width of the tube 1, and the inner margins of these side sections overlap one another from the apex of the triangular closure flap 59 to the apex of the trapezoidal portion 65 of the closure flap 61. As herein shown, the inner margin 67 of the side 4' section 51 laps over on the outside of the inner margin 69 of the side section 49. It will-be observed that one end of the inner margin 67 of side section 49 is defined by the edge portion 31b of the plies at one side of slit 31, and that the corresponding end of the inner margin 69 of the other side section 49 is in the form of a triangular peak projecting out beyond end 31b, having aside edge constituted by the edge portion 31a of the plies at the other side of slit 31. The latter enables the lapping of the margins without bunching. 7

After the opening up of the bottom closure formation as shown in FIG. 7, the tab 43 is folded over on a line 71 registering with edges 39b, 37a and tucked in underneath the side sections 49 and 51 of the closure formation, as shown in phantom in FIG. 7 and as appears in FIGS. 8 and 9. A pattern of adhesive, e.g., paste, designated in its entirety at P in FIG. 10 is then applied to the closure formation. This pattern is generally in the shape of an E, having a base stripe P1 extending across the inside face of the tongue 41 contiguous to the fold line 71 of tab 43 and extending approximately to the side edges 35a and 33b of the tongue, outer stripes P2 and P3 extending from the end portions of stripe P1 all the way across side sections 49 and 51, and an intermediate stripe P4 extending generally from the center of stripe P1 across the inner margins of the side sections 49 and 51 overlying inner margin 67 of side section 51 and the adjacent area of the other side section 49, this latter stripe 64 covering the portion of the serrated edge 47 of the plies included in side section 51. Then, the first closure flap 49 is folded over on fold line 13 to adhere it on the outside of the central rectangular area 53, and the second closure flap 61 is folded over on fold line 15 to adhere it on the outside of the first closure flap, as shown in FIG. 11, thereby completing the formation of a rectangular bottom 73 for the tube 1 (generally referred to as a square bottom although it may be longer than it is wide).

Reverting to the inter-ply pasting of plies 9 and 11, it will be observed by reference to FIGS. l-S that the inner and outer plies are pasted together at the bottom end of the tubing by a stripe of paste 75 which extends across Wall 3 from the 45 line 19 to the left side edge of the tube 1, which continues on through the left-hand gusset 7, and which then extends across the other wall 5 of the tube to the edge 35b of the slit 35. The effect of this is that the plies 9 and 11 are pasted together all along the inner margin of side section 49 of the bottom formation to prevent sifting of the contents of the bag between the plies. Also, the inner and outer plies are adhered together by spots of paste as indicated at 77 in the region of the folded-in tab 43.

As regards the completed closure, it is of importance to note that, with the tab 43 folded in on line 71 and tucked in underneath the side sections 49 and 51, the possibility of sifting out of the contents of the bag at the intersections of slits 37 and 39 with the diagonal folds'23 and 25 is minimized, particularly in relation to a construction wherein the tab' is not infolded and is left to remain as shown in solid lines in FIG. 7. This is because, with the infolding of the tab, none of the inner ply slitting is left unpasted or exposed. The construction approaches that of two complete bottoms, one for the inner ply and one for the outer ply.

The infolding of the tab 43 is of further significance when the inner ply 9 is made of laminated material such as above described with polyethylene on its inside face. This is because a polyethylene surface does not lend itself to secure pasting or gluing, and, if the tab 43 were not infolded, but left to remain as shown in solid lines'in FIG. 7, its exposed polyethylene face could not be firmly adhered on the outside of the first closure flap 59.

It is of further importance to note that the provision of slit 31 in both plies eleminates bunching of the plies such as would otherwise occur at the apex of the first closure flap 59, due to thelapping 'of the inner margins of side sections 49 and 51 of the closure formation. This lapping of the inner margins of theside sections 49 and 51, in conjunction with the inter-ply pasting at 73, minimizes the possibility of sifting and introduction of the contents of the bag between the plies. Also, the provision of the stripe of paste P4 overlying the inner margin 67 of side section 51 and the adjacent area of side section 49 tends to attain some degree of adherence between the lapping margins of the side sections, particularly when the edge 47 is serrated and has torn fibers projecting therefrom as herein shown, thus reducing the possibility of sifting. The E-shaped paste pattern P is also a unique feature, as distinguished from use of a solid (rectangular) application of paste over substantially the entire area of the closure formation, efiecting pasting in such a way as to minimize sifting without making the bottom undesirably stiff and without causing undesirable distortion of the bottom. It enables omission of paste where paste is unnecessary and allows for better control of paste application and bottom formation.

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 formed from a tube having an inner ply and an outer ply, said tube being a gusseted tube having opposed walls joined by gussets at the sides of the tube, one wall of the tube having a first pair of slits in the outer ply only and a second pair of slits in the inner ply only extending inward from one end of the tube constituting its bottom end, the slits of the first pair being located adjacent the sides of the tube and the slits of the second pair being located between the slits of the first pair on opposite sides of the longitudinal center line of said one wall, the portion of the inner ply between the slits of the second pair constituting a tab, a lower portion of one of said walls being folded back on a fold line extending transversely across the tube to provide a bottom closure formation having two side sections and including a central rectangular area, a first closure flap of generally triangular shape at one edge of said central rectangular area and a second closure flap at the opposite edge of said rectangular area, said second closure flap including the rectangular tongue portion of the outer ply bounded by the slits of the first pair, and a trapezoidal portion derived from the inner ply having said tab at its apex, said tab being folded in underneath said side sections of the closure formation, said first closure flap being folded over on a fold line at said one edge of said central rectangular area of said closure formation and adhered to the outside thereof, and said second closure flap being folded over on a fold line at said opposite edge of said central rectangular area of said closure formation and adhered to the outside thereof and to said first closure flap.

2. A bag as set forth in claim 1 wherein the inner margin of one of 'said side sections overlaps the inner margin of the other.

3. A bag as set forth in claim 2 wherein one of the walls of the bag has a slit in both plies extending inward from the bottom end of the tube so located as to define a non-'bunching end for the inner margin of one of said side sections at the apex of the triangular closure flap.

4. A bag as set forth in claim 3 wherein a stripe of adhesive is provided over the inner margin of said one side section and the adjacent area of the other side section.

5. A bag as set forth in claim 4 wherein the bottom edge of the tube is serrated for adherence together of said overlapping margins by said stripe of adhesive.

6. A bag as set forth in claim 2 wherein the closure flaps are adhered in place by a pattern of adhesive comprising a stripe of adhesive across the inside face of the rectangular tongue portion of the'outer ply and a plurality of stripes of adhesive extending therefrom across said side sections, one of the latter stripes overlying the inner end edge of the margin of said one side section that overlaps the inner margin of the other.

7. A bag as set forth in claim '6 wherein the bottom edge of the tube is serrated so that said inn r end edge of the inner margin of said one side section is serrated for adherence together of said overlapping margins by said one stripe of adhesive.

8. A bag as set forth in claim 2 wherein the inner and outer plies are adhesively secured together by a stripe of adhesive all along the inner margin of said other side section.

9. A bag as set forth in claim 8 wherein the inner and outer plies are adhered together in the region of the folded-in tab.

10. A bag as set forth in claim 1 wherein the inner play is comprised of multi-layer material having an outer paper layer and an inside plastic face.

11. A bag formed from a gusseted tube having opposed walls joined by gussets at the sides of the tube, a lower portion of one of said walls being folded back on a fold line extending transversely across the tube to provide a bottom closure formation having two side sections, and including a central rectangular area and first andvsecond closure flaps at opposite edges of said central rectangular area, the inner margin of one of said side sections overlapping the inner margin of the other, the first closure flap being folded over on a fold line at the respective edge of of the central rectangular area of said bottom formation and adhered thereto, and the second closure flap being folded over on the respective edge of the central rectangular area of said bottom formation and adhered thereto and to said first closure flap, adherence being by a pattern of adhesive including a stripe of adhesive overlying the inner end edge of said one side section.

12. A bag as set forth in claim 11 wherein the bottom edge of the tube is serrated so that said inne end edge of the inner margin of said one side section is serrated for adherence together of said overlapping margins by said one stripe of adhesive.

13. A bag as set forth in claim 11 wherein the first closure flap is of generally triangular shape and the bottom end of the tube has a slit so located as to define a non-bunching end for the inner margin of one of said side sections at the apex of said first closure flap.

14. A bag as set forth in claim 11 wherein the first closure flap is of generally triangular shape and the second closure flap has a tongue defined by slits in one wall of the tube, said pattern of adhesive comprising a stripe of adhesive extending across the inside face of said tongue and a plurality of stripes of adhesive, one of which is the stripe overlying the inner end edge of said one side section, extending across said side sections.

15. A bag as set forth in claim 14 wherein the pattern is of E-shape.

16. A bag formed from a gusseted tube having opposed walls joined by gussets at the sides of the tube, one wall of the tube having slits extending inward from one end of the tube constituting its bottom end defining a tongue, a lower portion of one of said walls being folded back on a fold line extending transversely across the tube to provide a bottom closure formation having two side sections and including a central rectangular area, a first closure flap of generally triangular shape at one edge of said rectangular area and a second closure flap at the opposite edge of said rectangular area including said tongue, the inner margin of one of said side sections overlapping the inner margin of the other, said first closure flap being folded over on a fold line at said one edge of said central rectangular area and adhered to the outside thereof, and

said second closure flap being folded over on a fold line at said opposite edge of said central rectangular area and adhered to the outside thereof and said first closure flap, one of the walls of the bag having a slit extending inward from the bottom end of the tube so located as to define a non-bunching end for the inner margin of said one side section. 1 v

8 References Cited UNITED STATES PATENTS 2,600,487 '6/1952 Craig 229 59 6/1956 Brady 229-55

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