FI64546B - SIDOVIKT SAECK - Google Patents

Description

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Patent- and regieterityreleen 'AmMon uttefd och utijkriftan publieend uo. oj (32) (33) (31) Requested «Tuotkeu * —B ^ ird priority * 07.03.77

Federal Republic of Germany-Förbundsrepubliken Tyskland (DE) P 2709823-3 (71) Viindmöller & Holscher, Munsterstrasse 1 + 8-52, 1 + 5 ** Lengerich i.W.,

Federal Republic of Germany - Förbundsrepubliken Tyskland (DE) (72) Horst Schmidt, Kattenvenne, Federal Republic of Germany - Förhundsrepubliken Tyskland (DE) (7M Leitzinger Oy (5 * 0 Pleated sack - Sidovikt säck

The invention relates to a large thermoplastic bag with a welded bottom seam bent from the side.

Side Folded sacks with welded, glued or sewn bottom seams with a wedge-shaped or rectangular bottom are known in various embodiments. However, the disadvantage of the known side-folded sacks is that the filling of the sack places a great strain on the bottom seams so that they cannot be used as large sacks for which high demands are placed.

Side-folded sacks with reinforcing strips sewn into the bottoms associated with the adjacent wall portions are known, for example, from Canadian Patent 542,114 and U.S. Patents 2,493,349 and 2,740,577. form triangular sections in the region of the base. In known sacks, it follows from the wedge effect that the filler tends to inflate the sewn-in wall parts in the area of the base, which poses a risk of tearing of the base seam stitches. In addition, the filler loads the triangular portions of the 2 64546 side folds rising from the bottom very strongly so that the wedges of the side folds formed by the bottom seam tighten to the extreme, which not only strains the sack material but also the already overloaded bottom seam to the extreme.

If the side-folded sack is made of a heat-sealable or weldable material, the bottom seam is stressed from its surface, which is the most undesirable form of load on the weld seam.

Although side-folded sacks can be produced simply because it is only necessary to equip the side-folded hose section with bottom seams, the load capacity of such a bag remains within narrow limits, because the bottom seam forming the weakest point is subjected to the strongest stress.

In hose sections made of a layer of woven or plastic strips to which a plastic foil is attached on one or both sides, it is not suitable to use, as is known, a simple butt weld when the bottom is of a material corresponding to a very durable sack material. Admittedly, welding the base, for example by jet welding, would achieve complete welding of the layers forming the base and thus good tightness. But welding would cause deterioration in the strip or fabric layers reinforcing the sack material in the area of the seam, so that it is at this point that the sack would suffer unfavorable deterioration, which is already particularly stressed due to the beam and notch effect. Furthermore, the reinforcing fabrics or deposit-forming strips show a strong shrinkage capacity, so that there is a risk that they will withdraw from the weld seam due to the heat of welding. For example, drawn polyolefin provides at least a tenfold increase in durability. Until now, however, it does not make sense to use foil reinforced with drawn pcblyolefin strip, for example, as a material for side-folded sacks, because the durability of the sack material would again deteriorate due to the bottom weld seam in the critical and highly stressed bottom area.

It is an object of the present invention to provide a side-folded sack with a base shape which corresponds in strength to the strength of the sack material used.

3,64546

According to the invention, this object is achieved by providing a flat sack with side folds made of reinforcing fabric or a layer of plastic tape with a tightly welded bottom seam which folds the welded end of the hose corresponds to the width of the hose section and the length of the extended rectangular base. In the side-folded sack according to the invention, all the locations of the side-folded hose section, which hose section is made of coated fabric or deposit, are completely joined or fused together in the area of the base by a weld seam so that the tightness of the base is ensured. The area of the bottom seam weakened by welding is folded into a smooth piece of hose and a bottom cover is attached to the area of the bottom, which surrounds the seamed area of the centrally welded sack end and which removes the forces leading to fracture of the bottom weld. When filled, the side-folded sack according to the invention most preferably forms a bottom cover made of a more rigid material so that this forms a rectangular bottom. The bottom cover extends over the weaker area provided by the bottom hose seam so that / the strength of the bottom is at least the same as that of the sack material used. Since the bottom cover is rectangular from the bottom, there are no very heavily stressed areas in the wedge areas of the side folds rising from the bottom, because the substantially flat triangular parts of the bottom side folds are subject to more favorable stress distribution and stress concentration is concentrated in triangular areas.

The weld of the base can be made by radial welding or ordinary welding, which causes complete adhesion of the material in the area of the base, i.e. melting. The base cover can be attached to the base area with an adhesive, such as a Hotmelt adhesive, or other method to ensure that the drawn strips no longer reach the thermal softening limit.

Container sacks are formed on the base according to the invention, which until now could not be made as side-folded sacks.

U.S. Pat. No. 3,807,626 discloses a side-folded sack with a layered bottom and a foil pressed as an inner wall and having a plastic foil 4! 64546 and is covered with an elongate strip folded from the side wall, folded to the opposite side wall and glued thereto, wherein a tear wire covered by the strip is further arranged parallel to the end face of the plastic hose foil. However, the wall strip surrounding and glued to the opposite wall of the sack does not form any base plate, but is intended to protect a compressed plastic foil which, when opened, can be removed from the wall strip on top by tearing with a tear wire.

An embodiment of the invention will be explained in more detail with the aid of the accompanying drawings, in which:

Figure 1 shows a schematic side view of a side-folded sack with a bottom cover.

Figure 2 shows a side-folded sack of Figure 1 in a perspective view in the form in which it is filled.

The side-folded hose piece 1, which consists of a layer reinforced with a layer, fabric or otherwise, is welded together at its lower end by a weld seam 2 extending to all layers. The end provided with the weld seam 2 of the hose piece 1 is folded over itself from above the weld seam and this fold is arranged centrally on the bottom cover 3 as a fold 5, which bottom cover is glued to the hose piece by the hot melting method 4. with the installation of the base cover 3; the fact that it is folded with the welded end of the hose section means that it cannot subsequently come off or go wrong and the base cover cannot protrude. With the glued base cover 3, not only is the base further reinforced, but it also prevents the weld seam 2 of the base from being affected by forces that could damage it.