GB2043027A - Bag - Google Patents

Abstract

A bag has a closure formed by folding the end portions E of the side walls 3, 4 of a flat tube 1 about a line 10. The outside of side wall 3 is glued to its own folded-over end portion and is glued to the folded-over portion of the other side wall 4 through openings 9 in its end portion. The openings are cutouts (as shown) and/or holes. <IMAGE>

Description

SPECIFICATION Bag The invention relates to a bag, for example a paper bag or a sack, whose bottom or end closure has been formed by folding one end portion of a flat tube over a transverse folding line on to the outside of one side wall of the flat tube and by gluing the folded portion to the said side wall. The invention also relates to a flat tube for use in making such a bag.

Designs of bags are known in which, at one end of a flat tube, one side wall is longer than the other, or, where multi-layered sacks are involved, the individual layers have different lengths, such that there is a graduation from the inside to the outside. After an adhesive has been applied to the parts to be folded over a transverse line, the said parts are folded over and secured to the outside of the shorter side wall by means of the adhesive. On account of the projection of one side wall beyond the other, a narrow area of the longer side wall is also covered by the adhesive. Although this ensures security of the closure, preparation of tubes with side walls of different lengths requires considerable expenditure as well as special equipment and it also entails considerable loss of material.

What is desired is a bag construction in which a secure closure at the end or bottom may be obtained in a relatively simple manner, without a projection in length or the like being absolutely necessary.

According to the present invention the side walls in the end portion have the same length before the end portion is folded over, and one of the two side walls which are superimposed in the end portion is provided with openings, cutouts or holes, and the application of an adhesive on the side of the end portion in question is also effected over the openings, cutouts or holes, in such a way that adhesion of the folded-over end portion to the outside of the adjacent side wall is effected not only between those areas of the said side wall itself which are folded against one another but also between the said side wall and the points on the other side wall left free by the openings, cutouts, or holes.

Such a bag may easily be produced in the usual manner. No special measures or special equipment are required for producing a flat tube with a projection of one side wall beyond the other, but rather the tube is produced with edges at the same level. The openings (e.g. cutouts or holes) in the end area may be produced by a cutting or punching process which may be incorporated without difficuity into the normal production sequence.

In one advantageous embodiment, at least one of the openings starts at the edge of one side wall.

It is also possible, however, to provide at least one of the openings with a closed contour.

The bag can, moreover, be variously designed, according to the intended use. It may be formed as a flat bag or a bag with gussets. It may be singlelayered or multi-layered, and the individual layers may consist of different materiais. In the case of a multi-layered bag it may be expedient to join together, at least partially, the layers of one or both side walls in the said end portion, for example by an adhesive. It is also possible to provide the bag with an inner lining, for example of plastics foil; the inner lining need not be integrated in the structure of the bottom or end closure of the bag, but may have its own closure, for example a welded seam.

Irrespective of the individual design, an externals cover sheet may also be attached, for example by gluing, to the bottom or end closure of the bag.

The invention will be described further, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of one end of a tube used to form a bag, the side walls being shown for the sake of clarity at a distance from one another instead of in the adjacent position; Figure 2 shows one end of a tube in the making of another embodiment of bag, on a smaller scale, prior to the folding over of the end portion; Figure 3 shows the bottom or end closure formed by folding over and gluing the end portion seen in Figure 2; and Figure 4 is a section on line lV-IV in Figure 3.

In Figure 1 one end of a tube 1 provided with gussets 2 is shown; the sheet material of the tube consists of two layers of kraft paper. The side walls 3, 4 of the tube 1 have the same length in the end portion E, so that their edges 5, 6 cover one another without an offset in the longitudinal direction of the tube portion when the side walls are superimposed. The two paper layers - not shown in detail - of each side wall of the tube are glued completely or partially to one another in the vicinity of the edges 5, 6 as shown by broken lines 7, 8.

The side wall 3 at the front (as seen in Figure 1) is provided with cutouts 9 which start at its edge 5; they are rectangular in this example but may have another shape. These are formed by a cutting punch in the course of making the tube.

In the forming of the bottom or end closure, the two side walls 3 and 4 lie against one another, in contrast to the view in Figure 1. When an adhesive is applied, in the end portion E, to the front side wall 3, it covers not only the parts of the outside of this side wall 3 which lie in the portion E, but at the same time also reaches the parts of the inside of the rear side wall 4 which are exposed on account of the openings 9. When the two side walls are folded over the transverse line 10 delimiting the end portion E are placed against the outside of the front side wall 3, both the end portion of the front side wall 3 and the end portion of the rear side wall 4 will be stuck to the outside of the front sidewall, so that a stable and secure bottom or end closure is obtained, which can withstand even quite heavy stresses.

In the embodiment according to Figures 2 to 4, which for example is single-layered, edge cutouts 11 in one side wall 13 in the edge portion E are in the shape of segments of a circle. An adhesive applied to the end portion of the wall 13 also reaches, therefore, the respective points on the inside of the other side wall 14.

Figure 3 shows the bag with the bottom or end closure B formed by folding the end portion E over the transverse folding line 10. The adhesion includes parts 1 5 and 1 6 on both the folded-over side wall portions (Figure 4).

Figure 2 shows with a dash-dot line that, instead of edge cutouts, or where necessary in addition thereto, openings 1 7 with a closed contour (holes) may be provided in the one side wall, in the end portion E.

In addition a cover sheet 12 may be glued to the folded-over and glued end portion, as shown in Figure 3, in order to cover the edge of the end portion E.

The other end of a bag provided with a bottom closure as described above may be formed as desired. The invention also includes the possibility, however, of forming the other end with a closure in the same way as, or at least similarly to, the bottom end, after filling the bag. Therefore, the filling end of a bag may appear as shown in Figure 1 for example.

The bags described above are suitable for widely differing types of filled materials, for example feedstuffs, chemical products and agricultural products.

Claims (10)

1. A bag having a closure which has been formed by folding adjacent end portions of the side walls of a flat tube at one end of the tube over a transverse folding line on to the outside of one of the side walls, the side walls being of the same length at the said one end of the tube before folding, the end portion of the said one side wall having openings, the outside of the said one side wall being glued to its end portion and being glued to the other end portion through the openings.

2. A bag as claimed in claim 1, in which at least one of the openings is a cutout which starts at the edge of the end portion having the openings.

3. A bag as claimed in claim 1 or 2, in which at least one of the openings has a closed contour.

4. A bag as claimed in any of claims 1 to 3, in which the bag has gussets between the side walls.

5. A bag as claimed in any of claims 1 to 4, in which the bag is multi-layered.

6. A bag as claimed in claim 5, in which the layers of at least one of the end portions are joined together over at least part of the end portion.

7. A bag as claimed in any of claims 1 to 6, in which the edges of the end portions are at least partially covered by a sheet.

8. A bag as claimed in any of claims 1 to 7, in which the other end of the bag has side wall end portions of equal length, one of them having openings so that, after filling of the bag, a closure similar to that provided at the said one end can be formed.

9. A bag as claimed in claim 1, substantially as described with reference to Figure 1 or Figures 2 to 4 of the accompanying drawings.

10. A flat tube for forming into a bag as claimed in claim 1 , the side walls of the tube being of the same length at one end of the tube, the end portion of one of the side walls having openings.

1 A flat tube for forming into a bag, substantially as described with reference to, and as shown in, Figure 1 or Figure 2 of the accompanying drawings.