Bag made of thermoplastic foil.

The invention relates to a bag made of thermoplastic film consisting of an equipped with inlaid gusseted tubular portion in the region of its formed by a transverse bottom weld soil and / or in the region of its later opening to be closed page called Eckabschweißungen forming by a transverse head weld, by the two each outer layers of the gusset is provided executed welds which obliquely extend from the outer edges of the side folds inwards and towards the bottom and / or later head welds and in the Innenfaltkanten, and provided with openings for venting the filled bag is.

In one known from EP-OS 92 885 Sack of this kind, the vents are located on the stacked in shallow blind inner walls of the gusset in a direction parallel to the top and bottom welds strip containing the gusset welds and the width of the projections outside the folding corresponds, on the inner parts of the diagonal split by the gusset welds parts of the walls of the middle area. In this known bag, the vent openings are covered while in the filled state by this overlapping outer gusset parts of the floor, so that they form no direct outside, the bag perforating openings. In the formed by the gussets, outwardly open pockets can still but easily penetrate moisture and water and pass through the vents into the interior of the bag.

The object of the invention is therefore to provide a bag of the type described, which vents are better protected against external influences, and especially against the ingress of water or moisture into the sack.

This object is achieved in a bag of the generic type in that the Eckabschweißungen forming welds are executed with venting ducts forming interruptions and that at least one respective wall of the gusset formed by the Eckabschweißungen having perforations. The bag according to the invention is, as it is provided with a labyrinth arranged ventilation ducts and vents, so that moisture and water can not reach or under extremely unfavorable conditions in the interior of the bag.

The labyrinth effect is additionally improved if only the inside, stacked in flat-lying unfilled sack walls of the gussets are provided with perforations. In another embodiment of the invention it is provided that the gussets of the bags lying flat are provided with at least one guided through all four layers of the side folds perforation. Such continuous perforations are easier to install than the inner walls of the gussets detecting holes.

The the object underlying the invention is further achieved by the Eckabschweißungen forming welds end at a distance from the outer edges of the flattened tube and that in parallel to which the Eckabschweißungen forming welds and at a slight distance to them from the outer edges obliquely inwardly extending welds are provided in order to form labyrinth seals.

Advantageous further developments of the second solution according to the invention are described in the dependent claims 5 to 8. FIG.

Embodiments of the invention will be explained hereinafter with reference to the drawing. Show this<ul><li>FIG. 1 shows a part of an existing of gusseted bags bag chain,</li><li>Figure 2 shows a section through a flat-lying sack of bag chain along the line II -., II in Figure 1.</li><li>Figure 3 shows a section through a bag of bag chain of Figure 1 along the line III -. And III in Fig. 1.</li><li>Fig. 4 shows a part of an existing of gusseted bags bag chain after the second inventive solution.</li></ul>

In Fig. 1 a bag chain 1 is shown from lying flat gusseted bags, which are formed from a gusseted tubular web 2. The tubular web gusseted 2 is for manufacturing the individual gusseted bags at equal distances from each other provided with bottom seams 3, with perforation 4 and Eckabschweißungen.

The Eckabschweißungen forming seams 5 are continuously formed, but they have interruptions 6 to form the venting channels, can escape through the 7 existing at a filled bag of air in the interstices. Thus, the air can escape even from the interstices 7, are - as shown in FIG. 2 - the inner superposed layers 8 provided in the gusset area with cutouts. 9 In such an embodiment, therefore, the air escapes via the channels 6 into the nip welds 5 in the gusset 7 and from there via the punched-9 to the outside. In this way, a labyrinth seal is achieved despite good ventilation.

According to the embodiment shown in FIG. 2, the punched-out must be 9 attached by means of an internal tool. Although this configuration provides better sealing, does, but more expensive.

If you want to avoid this internal tool, it is advisable to provide gussets 7 'passing through all four layers of punched holes 9' according to the embodiment of FIG. 3. In this embodiment can be processed with an external gear stamp. Compared with the embodiment of FIG. 2, however, results in a labyrinth-like seal, which is not quite as effective as these.

Depending on requirements, the labyrinthine vents described can be provided only in the head region, both in the floor and head area. Also possible is an embodiment in which a vent is provided on only one side of the bag in the head region.

Fig. 4 shows a bag chain l 'from lying flat gusseted bags, which are formed from a gusseted tubular web 2. The bag chain 1 of Fig. 4 corresponds essentially to that of Fig. L. The tubular web gusseted 2 is for manufacturing the individual gusseted bags at equal distances from each other provided with bottom seams 3, with perforation 4 and Eckabschweißungen.

The Eckabschweißungen forming welds 5 'end at a distance from the outer edges 11 of the flattened tube 1'. In order to form labyrinth seals 13, extending parallel to the Eckabschweißnähten 5 'and at a small distance to these from the outer edges 11 obliquely inwardly extending welds 14. These welds 14 may have different lengths, as can be seen from Fig. 4. The Entlüftungsausstanzungen 9 'correspond to the punch-outs, which are shown in Figs. 1 to 3.