Pleated-side bag or sack made of flexible, weldable material

Abstract

A pleated-side bag or sack of flexible weldable material with a closed bottom end and a top end provided with an internal reclosing device has side pleats inserted V-wise between two bag walls forming a front wall of the bag and a back wall of the bag. The pleats extend from a bottom end to a top end. A reclosing device is formed by two pressure sealing strips below the top end. The two pressure sealing strips are formed by two hook-and-loop strips of weldable material which are fastened in parallel alignment opposite one another on the two bag walls, occupying substantially an entire interior bag width, and the side pleats project with their two V-panels between the hook-and-loop strips into the bag interior.

Description

[0001] The invention relates to a pleated-side bag or sack of flexible, weldable material having a closed bottom end and a top end provided with an internal reclosing device, the sides inserted in V-shape between the two walls, which form the front wall and the back wall of the bag running continuously from the bottom end to the top end, and the reclosing device being formed by two pressure-sealing strips, which can be brought into mutual closing engagement under the top end.

[0002] Side-pleating bags or sacks of this kind are used for packing different materials in pieces, grains or powders which, after the removal of the end closure, for example, a weld seam, are taken out as a rule in portions. The reclosing device makes it possible for the user to reclose the bag or sack after each removal of its contents or to open it again.

[0003] Side-pleating bags, in which the pressure closure strips of the reclosing device are formed by two strips, which can be brought together as tongue and groove into closing engagement by the application of pressure, of which the one, for example, the groove strip is fastened to one wall of the bag, and the other, the tongue strip in the example chosen, to the opposite half of the side-pleat and to the area of the other wall of the bag between these two side pleat halves. The tow other side pleat halves, which have not received the pressure closure strip are permanently bonded, for example, welded, to the adjacent bag wall.

[0004] Admittedly, by these means, it is possible to reclose the bag or sack after removing contents. However, on the other hand, it is undesirable during the previous removal of contents that the side pleats cannot be spread out completely flat, as would be required for creating the large-format opening made possible by the shape of the bag. This is due to the fact that in each case one half of the side pleats is permanently bonded to the adjacent bag wall, which results in a corresponding restriction of the opening cross section. In the known designs, the reclosing operation itself is problematical, since it is often difficult to bring the narrow, rib-like tongue of the one closure strip together and thus in engagement with the corresponding narrow groove in the other closure strip.

[0005] The invention addresses the problem of creating a side-pleated bag or sack of the kind referred to above, which will permit a maximum possible opening of the bag or sack at the top end for removal of contents and in which, at the same time, the reclosing device will assure easy reclosing of the bag or sack after contents have been removed.

[0006] This problem is solved by the invention with a configuration of the side-pleated bag or sack of claim 1. Since, with this configuration, the two pressure closure strips are fastened in parallel mutual alignment opposite one another at the two walls of the bag and the side pleats spring forward with their halves or limbs pleated V-wise and there is no bonding of one side pleat half with a bag or sack wall, both halves of the side pleats can be spread apart flatly together unhampered at the top end to open the bag, so that the largest possible opening of the bag is created for the removal of its contents. Designing the two pressure closure strips as hook-and-loop strips greatly also facilitates reclosure since, as is commonly the case with hook-and-loop closure strips, a full-surface mutual interlocking can be brought about over the entire width of the closure strips by the application of pressure. Thus the bag or sack can be reclosed even when the two hook-and-loop strips to be brought in interlocking engagement are slightly offset from one another, which is not the case with tongue-and-groove closures. A hook-and-loop strip width of about 10 to 20 mm has proven advantageous in this connection.

[0007] Fundamentally, in the scope of the present invention, any appropriate hook-and-loop closure strips available commercially can be used, both in the classical mode, in which one strip is provided with small hooks on its attaching surface, which hook into the tangled surface of the other strip under pressure, or also in another embodiment favorable to bag manufacture, in which the hook-and-loop strips have similarly configured adherent surfaces with catching means, which can be brought into interlocking engagement. Such catching means can be in the form of, for example, projections distributed over the attaching surface with somewhat mushroom-like thickened heads or shaped in the manner of double cones, which can be brought with the application of pressure into mutual interlocking engagement and can be released again by appropriate application of traction.

[0008] Additional features and advantages of the invention will appear in the claims and in the following description, in conjunction with the drawing, in which a plurality of embodiments of the subject of the invention are represented schematically. In the drawing:

[0009] FIG. 1 shows a frontal view of the upper portion of a side-pleating bag in the inactive state with a partially cut-away front wall of the bag,

[0010] FIGS. 2 to 6 are each a cross section taken on line A-A of FIG. 1 on a reduced scale in order to show each embodiment of the invention, and

[0011] FIG. 7 shows a view corresponding to FIG. 1 in which, however, the bag is represented in the open state with the side creases spread flat.

[0012] The pleated-side bag represented by way of example in the drawing can be formed as a plastic bag of a film of thermoplastic material, especially a polyolefin such as polyethylene or polypropylene, or as a compound bag of a compound material, which bears at least, on its inside, a layer of thermoplastic capable of being welded, while one or more externally adjoining layers of the compound material can be of a different nature. For example, two-layer compound films or laminates of thermoplastic can be used, it being desirable that the layers to be welded together during bag manufacture have a lower melting point than the outer layer of the material.

[0013] In particular, the bag in the selected example, consisting of a single plastic film and identified as a whole by the number 1, has a sealed bottom end, not shown, made in any practical manner, and a top end 2 which, when the bag 1 is empty as shown in FIG. 2 and, after the bag is filled, is closed with a welded seam along the upper marginal edges 3 of the bag walls 4 and 5, as indicated in FIG. 1 by a dash-dotted line 6.

[0014] The bag wall 4 constitutes the front wall of the bag, while bag wall 5 forms the back wall of the bag. Between these, side pleats 7 are inserted on both sides, which extend from the bottom end of bag 1 to its top end 2 and end flush with the top marginal edges of the bag walls 4 and 5.

[0015] At an interval below the later welded seam 6, a reclosing device 8 is formed near the top end between the two bag walls 4 and 5 and comprises two hook-and-loop strips 9 made of weldable material like a thermoplastic film, of which the one is welded or heat-sealed or, if desired, also cemented to the front wall of the bag and the other is affixed to the back wall 5 by welding or heat sealing or in some cases by cementing. The hook-and-loop strips are arranged with respect to the central axis 10 of bag 1 in a common transverse plane with attaching surfaces 11, which are opposite one another and can be brought with their interlocking surfaces into mutual hooking engagement with one another. The reclosing device 8 is used by the consumer after removing the weld seam 6.

[0016] Each side pleat 7 has on both sides of its central crease 12 two side-pleat halves 13 and 14, which are joined along lateral weld seams 15 and 16 to the front wall 4 and back wall 5, respectively, of the bag. When the bag 1 is empty according to FIGS. 1 to 6, the halves 13 and 14 of each side pleat 7 lie flat one on the other V-wise and thus form the panels of a V projecting freely between the hook-and-loop strips 9 into the interior of the bag.

[0017] As it can be seen especially in FIGS. 2 to 6, the hook-and-loop closure strips 9 fastened to the inside of both bag walls 4 and 5 occupy virtually the entire interior width of the bag and, at the ends, they are drawn into the weld seams 15, 16, and fused to the material of the bag walls 4 and 5 and side pleats 7 by the welding operation that is performed. If such fusion into the seams 15 and 16 presents difficulties because, for example, of a higher melting point of the plastic used in the hook-and-loop strips, the hook-and-loop strips 9 can terminate at a short distance from the seams 15 and 16.

[0018] In the embodiment of FIG. 2, the side pleats 7 bear no hook-and-loop strips on their inside. A simple embodiment of this kind can recommend itself when, for example, the side pleats have but a slight depth, so that a closure of the two hook-and-loop strips 9 in the area between the side pleats 7 then flattened by the application of pressure may be sufficient. This depends, of course, also on the material packed in the bag 1.

[0019] In the embodiment of FIG. 3, the V-panels of the side pleats, that is, the side pleat halves 13 and 14, are provided with aligned punched holes 17 in a common plane containing the hook-and-loop strips 9 of bag walls 4 and 5. Thus, with respect to the example in FIG. 2, additional adherence of the hook-and-loop strip 9 in bag wall 4 to the hook-and-loop strip 9 in bag wall 5 through the punched holes 17 in the side pleats 7 is possible.

[0020] FIG. 4 visualizes an embodiment, in which the V-panels or side pleat halves 13 and 14 are provided on their inside with hook-and-loop strips 18 in a common plane containing the hook-and-loop strips 9 of bag walls 4 and 5, so that their adherent surface 11 is opposite that of the hook-and-loop strips 9. The hook-and-loop strips 18 extend over substantially the entire width of the side pleats 7, across the center creases 12 to the lateral weld seams 15 and 16, but do not reach into them, in order thus to avoid difficulties in the production of the weld seams 15 and 16 by increasing the number of layers to be welded. Such an embodiment, preferred at this time, permits an especially quick and comprehensive closure of the bag end by the intermeshing of the hook strips 9 on the bag walls 4 and 5 with the loop strip 18 on the adjacent side pleat halves 13 and 14 and with one another in the middle area between the side pleats 7.

[0021] The embodiment in FIG. 5 differs from the one in FIG. 4 only in that, instead of the hook-and-loop strips 18 running across the crease 12 on the inside of the V-panels or side pleat halves 13 and 14, individual smaller hook-and-loop strips 19 are disposed in dot form, so to speak, on both sides of the inner crease 12 with their catching surface 11 opposite the adjacent hook-and-loop strip 9 on the bag walls 4 and 5. The adhesion of the top end 2 of bag 1 is accomplished in this case in a manner similar to the embodiment in FIG. 4.

[0022] Lastly, FIG. 6 shows an embodiment, in which hook-and-loop strips 20 are provided similar to hook-and-loop strips 19 in FIG. 5, but on the outside of the V-panels or side pleat halves 13 and 14 with their active surfaces 11 opposite one another. The closure of the top end 2 of bag 1 takes place in this case between the outsides of the side pleat halves 13 and 14 directly between the hook-and-loop strips 20, and internally the area between the inner creases 12 of the side pleats 7 by the adherent bond between the hook-and-loop strips 9 on bag walls 4 and 5.

[0023] Whereas in FIGS. 2 to 6, the side pleats 7 with their V-panels 13 and 14 are shown, in the interest of clear representation, in an intermediate position between a position flat against one another (closed position) and a flat spread-open position (open position), from which it is apparent that with the side pleats 7 spread out flat, the full cross section of the mouth of bag 1 can be used for removing the contents.

Claims

1. A pleated-side bag or sack of flexible weldable material with a closed bottom end and a top end provided with an internal reclosing device, wherein side pleats inserted V-wise between the two bag walls forming the front wall of the bag and the back wall of the bag reach all the way from the bottom end to the top end and the reclosing device is formed by two pressure sealing strips, which can be brought into mutual closing engagement below the top end, wherein the two pressure sealing strips are formed by two hook-and-loop strips (9) of weldable material, which are fastened in parallel alignment opposite one another on the two bag walls (4, 5), occupying substantially the entire interior bag width, and the side pleats (7) project with their two V-panels (13, 14) between the hook-and-loop strips (9) into the bag interior.

2. The pleated-side bag or sack of claim 1, wherein the V-panels (13, 14) of the side pleats are provided with punched holes (17) in a common plane containing the hook-and-loop strips (9) of the bag walls.

3. The pleated-side bag or sack of claim 1 or 2, wherein the V-panels (13, 14) of the side pleats (7) are provided in turn with hook-and-loop strips (18, 19, 20) in a common plane containing the hook-and-loop strips (18, 19, 20) in a common plain containing the hook-and-loop strips (9) of the bag walls (4, 5).

4. The pleated-side bag or sack of claim 3, wherein the hook-and-loop strips (18) of the V-panels (13, 14) extend substantially over the entire width of the side pleats (7).

5. The pleated-side bag or sack of claim 3, wherein the hook-and-loop strips (19, 20) of the V-panels (13, 14) extend only over a part of the width of each V-panel (13, 14).

6. The pleated-side bag or sack of claim 5, wherein the hook-and-loop strips (19) are disposed on the inside of the V-panels (13, 14) in a position opposite in each case to a hook-and-loop strip (9) in the bag walls (4, 5).

7. The pleated-side bag or sack of claim 5, wherein the hook-and-loop strips (20) are disposed on the outer side of the V-panels (13, 14) with confronting adhesion surfaces (11).

8. The pleated-side bag or sack of any one of the claims 1 to 7, wherein the hook-and-loop strips (9) of the bag walls (4, 5) are drawn in with their ends into side wall welds (15, 16) of the bag (1), which join the side pleats (7) to the margins of the bag walls (4, 5).

9. The pleated-side bag or sack of any one of the claims 1 to 8, wherein the width of the hook-and-loop strips (9, 18-20) is approximately 10 to 20 mm.

10. The pleated-side bag or sack of any one of the claims 1 to 9, wherein the hook-and-loop strips (9, 18-20) have similarly shapes adherence surfaces (11) with catch members, which can be brought into mutual interlocking engagement.