Transport sack

(57) The invention relates to a transport bag, which is formed by sewing one or more fabric webs by means of square seams, and is characterized in that provided to form a tight seam (4) between the fabric webs (7) in the seam region, a sealing strip (8) and with the fabric webs, wherein the sealing tape (8) consists of elastic material and projects laterally of the seam into the interior of the transport bag.

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GQ

AT 403 155

HR 8ET79SC8

AT 403 155 Β

The invention relates to a transport bag, which is formed by sewing of one or more fabric webs by means of edged seams. Furthermore, the invention relates to a method for sewing the transport bag and the device therefor. Transport bags of the type mentioned are also called big bag.

Transport bags of this type are a cheap and frequently used transport medium for pourable goods. A bag can hold loads of up to several tons.

For dusty bulk goods, it is necessary to form the transport bag as close as possible. As a material for the transport bag usually coated fabric is used, eg Polypropylene fabric sheets with polypropylene coating or polyethylene sheets with polyethylene coating. In such densely formed transport bags arises during filling the problem that the air in the bag must escape under high pressure and at high speed, especially in fast filling operations. The high pressure and the high flow rate make it possible that even fine holes allow the dust to escape. A weak point in this regard is in particular the seam with which the various fabric webs are sewn to form the transport bag. The high filling pressure and the tensile load of the walls at the seams lead to an expansion of the sewing holes, which allow fine dusts such as nozzles to escape.

To remedy this disadvantage, it is already known to seal the seam area, that around the edge to be sewn a fabric tape or felt tape is wrapped and sewn to the outside with the fabric webs. However, this solution is very expensive because the tape must be relatively wide and expensive. The labor-intensive effort is high.

The sealing of flat seams by mitvernähen a sealing tape is known from the literature, which are sometimes very special applications. Thus, DE-OS 27 51 162 relates to the sealing of seams of motor vehicle concealment and DE-PS 32 09 054 the waterproof connection of plastic-coated fabric parts. FR-OS 2 634 468 probably describes a transport bag, but of that type in which the tightness is provided by a hinged further bag, wherein the problem underlying the invention can not occur at all.

The subject invention relates to the sealing of edged seams or stitched seams. In these, the problem arises that under high stress during filling of the bag spreads the walls and the suture holes are stretched.

According to the present invention, a transport bag is provided, which is characterized in that provided to form a tight seam between the fabric webs in the seam area a sealing tape and mitnahäht with the fabric webs, wherein the sealing strip consists of elastic material and the side of the seam into the interior of the transport bag protrudes.

In contrast to the known measures of inserting a sealing strip according to Vorhalte the effect according to the invention is not so much that the sewing holes are self-sealed. Rather, the effect is mainly the fact that the elastic sealing strip extends inwardly into the interior of the transport bag and settles when filling in front of the edge profile and thus exerts a sealing function, which takes place before the Nählöchern. If a sealing tape or belt is used as the material, as is preferably described, the air can escape through the seam area and yet the particles are prevented from escaping. So there is a filter effect.

For further seam sealing, a further sealing tape can additionally be sewn from the outside on one or each of the two sides of the seam.

So-trained seams are very dense and the manufacturing cost is one tenth compared to the method described above.

The sealing tape is preferably a woven, knitted or braided tape, such as a polypropylene multifilament wick. Such a wick is very soft and elastic. A preferred wick is about 15 mm wide and 4 mm thick in cross section. It can also be used round wicks.

In the production, it is necessary to insert the sealing tape between the panels and to guide so that the sealing tape is securely sewn. When manually feeding the sealing tape, it may occur inadvertently that this sewing does not run exactly and the sealing tape emigrates slightly inwards. Such an interface would not be tight.

To ensure proper feeding and sewing, the invention provides a device for feeding the sealing tape. This consists of a pivotally mounted on the sewing table guide lever having a guide at the leading end When swung state, the guide is located between the tissue webs to be sewn and ensures the exact supply of the sealing tape in the seam.

In the following the invention will be explained in more detail with reference to schematic drawings. Fig. 1 shows basically the structure of a transport bag. Figs. 2, 3 and 4 show a section through the

AT 403 155 Β sewn edge region of the bag and Fig. 5 shows schematically the process of sewing with the device according to the invention in an oblique view. Figs. 6 and 7 show two different embodiments of a transport bag in a schematic representation.

According to FIG. 1 For example, the transport bag consists of the four side walls 1, the bottom 2 and the lid 3. At the edges of the fabric webs are sewn by means of a seam 4, wherein outwardly projecting webs 5 remain. The lid 3 has a pour opening with sleeve 6. The bottom 2 may be closed at the bottom or provided with a corresponding discharge opening. At all four corners loops 25 may be provided to lift and hold the bag. The formation of the seams 4 and all other seams of the finished transport bag is preferred subject of the present invention.

When sewing 2 two superimposed fabric webs 7 are sewn by means of the seam 4 in the edge region as shown in FIG., Between the two fabric webs 7, the sealing strip 8 is arranged. As can be seen in FIG. 2, the sealing tape 8 is stitched together with the seam 4 and, in any case, also projects inwards into the interior of the bag.

FIG. 3 shows the behavior of the seam area during filling. The two fabric webs 7 are pulled apart with high force, wherein the seam 4 is subjected to high loads. The sewing holes opening in the process are closed by the sealing band 8 or sealed by a filter, since the elasticity of the sealing band 8 effects a seal, so that fine dusts can not escape through the seam holes of the seam 4.

Fig. 4 shows a seam formation, in addition to the sealing strip 8 between the fabric webs outside yet / or each another sealing strip 26 is arranged, which further enhances the seal.

In Fig. 5, the apparatus for forming the sealed seam is shown schematically. The sewing machine 9 is seated on the sewing table 10. The thread 11 runs over the usual guiding and tensioning devices to the needle 12. The sewing foot 14 fastened to the presser foot holder 13 and pushed down lies on the upper fabric web 7. Between the upper and lower fabric web 7, the sealing tape 8 is inserted and supplied so that it is mitvernäht with the formed seam 4.

The supply and lateral guidance of the sealing strip 8 by means of the guide lever 15 which is pivotable about the axis 16 on the sewing table 10. At the leading end 17, a guide hook 18 is provided which guides the sealing band 8 during the sewing process and, in particular, prevents it from emigrating into the interior of the bag. Instead of the guide hook and a guide eye can be provided.

In the position of the guide lever 15 shown in FIG. 5, the sealing tape 8 is inserted into the guide hook 18. Before the sewing process, the guide lever 15 is pivoted as indicated by arrow 19 until it rests against the sewing table 10 and the sealing tape 8 until shortly before the sewing foot 14 leads.

If the end region of a seam is reached, the guide lever can be pivoted outwards again and the sealing strip 8 cut accordingly and the seam can be sewn up.

In the event that in addition to the sealing strip 8, further sealing tapes are to be sewn from the outside, the further sealing tapes (26) can be supplied from below via the eyelet 20 at the sewing foot 14 and via a corresponding further guide eyelet of the sewing table (see FIG. 4). ,

Fig. 6 shows schematically an arrangement of fabric webs, wherein the side walls and the bottom of a U-shaped folded fabric web 21 and two further fabric webs 22 is formed, which complement the side surfaces. If desired, a separate lid can also be placed from above and sewn.

7, two U-shaped folded fabric webs 23, 24 are provided, which are sewn together in the position shown. The latter embodiment has the advantage that a completely closed transport bag can be produced with a single tight seam, which can be provided with the corresponding filling and filling openings at the top and bottom. All necessary seams can be sewn according to the invention with sealing tape.

The seams 4 are preferably chainstitch seams, but may also be formed as a lockstitch seam.