EP0445443A1 - Fusseted tubing made of stretch-film for packaging items - Google Patents

Abstract

The invention relates to a gusseted tubing (3) made of stretch film for the hood-type packaging of items (4), in particular piles of items, which tubing has a smaller circumference than the items to be packaged and whose free end portion is provided prior to stretching with a transverse seam with spacing from its free end, after which seam the portion forming a hood is to be separated, the width (b) of the supply or feed web of the gusseted tubing being at least approximately 95% of the width (B) of the items (4) to be packaged. <IMAGE>

Description

The invention relates to a gusseted tube made of stretch film (= stretch film) for the hood-like wrapping of piece goods, in particular piece goods stacked in a cuboid shape, which has a smaller circumference than the piece goods to be wrapped, and its free end section for forming a hood before stretching (= stretching) is provided with a transverse seam at a distance from its free end, behind which the one after laying the cross seam of a hood-forming section of the gusseted tube is to be cut off.

If the "width" of the piece goods or piece goods stack to be wrapped is mentioned above or below, this means the width of the side (s) of the piece goods or piece goods stack that are parallel (at least essentially) when the side gusseted tube is fed this runs (run).

In addition to this "width" and the height, the piece goods to be wrapped with stretch film therefore also have another significant dimension, namely the "depth", whereby "width" and "depth" can basically be interchanged, that is, one dimension as a rule has no priority over the other. In relation to the (generally roll-wound) side film tube, which forms a (for its consumption "endless") side gusseted tube reservoir for such a wrapping process, the dimension of the piece goods to be wrapped is therefore the "width" that occurs when the material is fed initially not yet unfolded side gusset hose runs parallel to this.

In order to avoid the disadvantages that have become known in the meantime (e.g. and in particular relatively large film consumption; relatively large investment volume due to the devices for applying heat; relatively high energy requirement; risk of ignition for certain goods, especially in the chemical industry, etc.) of shrink film packaging processes, one has already started partially switched over to using so-called stretch or stretch films instead of the shrink films, which do not require any heat in order to apply them closely to the piece goods to be packaged and thus in particular with regard to palletized To create a stack of piece goods, so-called loading units, which have a sufficiently high transport stability even for multiple repositioning and are also well protected against the weather with regard to the piece goods.

With this stretch film technology, it is sufficient if the stretch film material is "stretched" (= stretched) before wrapping the piece goods, whereby the (technical) term "stretch" generally does not mean any (however small) stretch of the starting material, Rather, in the sense of stretch technology, a considerable elongation of generally at least 10% and more, which in the wrapping state is then really able to create and guarantee the dimensional stability required for the required stack strength of packaged goods. Within the scope of the stretch film packaging technology, the so-called winding stretching has become known, in which web-shaped stretch film is wrapped around the piece goods to be wrapped, but this technology is associated with not inconsiderable disadvantages, so that it has therefore already started to be packed pieces or to cover packaged packaged goods with (at least) one film hood made of stretch film material, as is basically also known from shrink film packaging. However, considerable problems have arisen, particularly in the area of the weld seam, which have so far not been satisfactorily solved, at least in numerous applications.

A cross seam, which is generally required for the formation of a hood and is produced by welding, is just as unavoidable in the case of stretch film hoods which, for reasons of economy, are each formed from a section of a tubular film material with inserted gussets (= gusseted tube), as is the case with shrink film hood processes the case is. The difficulties in shrink film technology already indicated above have not been shown to be nearly as serious due to the heat applied and the restructuring of the molecules taking place as is the case with stretch film hood processes.

Such gusseted hoses are known to have a folded, as it were "flat" initial state, in which the gusseted tube material has two mutually parallel first side surfaces and two V-shaped inwardly folded second side surfaces. This known folding is therefore expedient in order to be able to store such tubular film material wound up into rolls in a space-saving manner (and thus also with a relatively small width). In addition, it has been shown that tubular film material folded in this way in the stored state can be opened better than is the case when the tubular film material is fed to a hood former in the unfolded state, in which the tubular film width is therefore equal to half the circumference of the tubular film.

In a method already practiced by the applicant (as well as by competitors), the transverse seam was formed by welding off a gusseted tubular film section in the as-yet unstretched original state in such a way that the corresponding end section of the gusseted tube supplied from a roll-shaped supply was practically in the form supplied ( and thus also the corresponding storage width of the tubular film) was welded, the weld seam therefore having a length that corresponded to the width of the mutually parallel first side faces of the tubular film. Since the circumference of a stretch film gusseted tube for the hood-like wrapping of piece goods in the non-stretched original state In accordance with the intended purpose, it is noteworthy (in some cases quite considerably) less than the length of the end edges of the piece goods or piece goods stack, to which the weld seam in the wrapped state runs parallel, in this way of working on the stretch, the weld seam is inevitably and necessarily subjected to a very considerable stretch, and not only for (transverse) stretching before wrapping the piece goods or piece goods stack, in which the tubular film must be widened so that it can be pulled effortlessly over the piece goods or piece goods stack, but also afterwards in the wrapped state. This is due to the fact that a stretch film hood is still subject to (in some cases considerable) elongation when it is properly attached to the piece goods or piece goods stack, whereby stretches of up to 30% and more can be provided (see, for example, DE-OS 37 07 877) .

In such a procedure, as has already been indicated, there are considerable problems in the area of the weld seam, in particular at the points at which the tips which inevitably arise in the case of such a tubular film hood in the wrapped state on the relevant end face of the piece goods or General cargo stacks lie on or on top of each other

In the method known from DE-OS 37 07 877 already mentioned, one has (presumably in an effort to avoid or reduce the problems outlined above) opened and stretched the side gusseted tube before placing the transverse seam and (transversely) it only then separated and welded from the tubular film supply in the desired length, i.e. practically in the no longer folded and already stretched state, which inevitably results in a weld seam, the length of which in the stretched state before the covering is (considerably) greater than the length of the one in the wrapped state State parallel to the front edge of the piece goods or piece goods stack to be wrapped.

Such a formation of the transverse seam, which is generally formed by welding, can now have the consequence that the internal stresses present in the film material are lost (largely or even substantially completely) during the plasticization of the film material during the welding process, so that they also after completion of the Welding process in the welded section are practically no longer present, but they remain in the rest of the film material, so that there may be tears or even tears, especially in the border areas between (generally welded) transverse seam and adjacent film material, especially when multiple wraps formed in this way Load units, which can lead to a loss of the required stack strength if there are corresponding tears and always to a loss of the urgently required tightness.

The present invention has for its object to provide a gusseted tube of the type described above, with which piece goods or piece goods stack can be easily wrapped with a stretch film hood while avoiding the above and other disadvantages.

This object is achieved according to the invention in that the supply or feed web width of the gusseted tube is at least about 95% of the width of the piece goods to be wrapped, wherein in an embodiment of the present invention it is preferably provided that the supply or feed web width the gusseted tube is substantially equal to the width of the piece goods to be wrapped. If this is the case, the finished wrapping condition occurs the loading unit practically no longer has any harmful tensions and there are no tears, unwanted corrugations, etc., because the weld seam in the unstretched (= unstretched) initial or feed state has more or less exactly the same length as before in the stretching of the film material Wrapping condition.

This gives (in particular compared to an embodiment in which the transverse seam length is significantly smaller than the corresponding width of the piece goods to be wrapped) the considerable advantage that the stresses occur essentially perpendicular to the transverse seam and no longer at any or random angles Cross seam, the latter in particular in the V-shaped double areas of the film can lead to overstretching, in particular in such a way that greater stresses occur in the film below than in the upper film section. On the other hand, in the configuration according to the invention of the stretch film side gusseted tube used as the wrapping material, the inner film tensions in the upper film section are greater than in the lower film section (which can be largely free of tension), so that the lower film sections in the V-shaped double region are easy Apply the tension of the upper film sections to the piece goods to be wrapped and the tensioned upper film sections ensure a smooth surface, which is highly useful not only for purely technical reasons, but is also desirable from an aesthetic point of view. The practically unstretched condition of the transverse seam area due to the configuration of the side gusset tube according to the invention does not involve any disadvantageous side effects, because in this area no stretch tensions are required for the desired tight or tight wrapping of the piece goods.

Even if this condition is strictly achieved only if the length of the transverse seam is chosen equal to the width of the piece goods to be wrapped, this effect of a very considerable improvement over the previously known side gusset tubes is already evident qualitatively and already in a quantitatively highly remarkable and noticeable extent if the length of the transverse seam is chosen to be only slightly smaller than the width of the piece goods, i.e. up to at least 95% of the piece goods width.

Fig. 1

eine schematisierte Seitenansicht eines zu einer Rolle aufgehaspelten Seitenfaltenschlauch-Vorrats mit von dem Vorrat bereits teilweise abgewickeltem freien Endabschnitt sowie einem darunter befindlichen Stückgutstapel, der mit einer Schrumpffolienhaube umhüllt werden soll;

Fig. 2

einen Schnitt durch den von dem Vorrat abgewickelten Abschnitt des Seitenfaltenschlauches gemäß der Schnittlinie II-II in Fig. 1 gesehen;

Fig. 3

eine Draufsicht auf den Stückgutstapel gemäß Fig. 1 von der Schnittebene III-III in Fig. 1 aus nach unten gesehen;

Fig. 4

eine (Teil-)Seitenansicht auf die Darstellung gemäß Fig. 1 in Richtung des Pfeiles IV in Fig. 1 gesehen, welche insbesondere den Seitenfaltenschlauch-Vorrat und den hiervon abgewickelten Endabschnitt zeigt;

Fig. 5

den teilweise aufgefalteten Seitenfaltenschlauch gemäß Fig. 2; und

Fig. 6

eine Draufsicht auf den Stückgutstapel gemäß den Fig. 1 bis 3 mit zusätzlicher Darstellung des völlig entfalteten, aber noch nicht gedehnten (gestretchten) Seitenfaltenschlauches (ausgezogene Linien) sowie den gedehnten (gestretchten) Seitenfaltenschlauch (unterer Endabschnitt) im gedehnten (gestretchten) Zustand kurz vor dem Überziehen über den Stückgutstapel.

The invention is explained below with reference to a schematic drawing. It shows:

Fig. 1

a schematic side view of a side gusseted hose supply reeled into a roll with a free end section already partially unwound from the supply and a stack of general cargo located underneath which is to be wrapped with a shrink film hood;

Fig. 2

seen a section through the portion of the gusseted hose unwound from the supply according to the section line II-II in Fig. 1;

Fig. 3

a top view of the piece goods stack of Figure 1 seen from the sectional plane III-III in Figure 1 from below.

Fig. 4

a (partial) side view of the illustration of FIG. 1 in the direction of arrow IV in FIG. 1, which in particular shows the gusseted tube stock and the end portion unwound therefrom;

Fig. 5

the partially unfolded side gusseted hose according to FIG. 2; and

Fig. 6

1 to 3 with an additional representation of the fully unfolded, but not yet stretched (stretched) gusseted hose (solid lines) and the stretched (stretched) gusseted hose (lower end section) in the stretched (stretched) state just before the covering over the general cargo stack.

1 and 2 of the drawing show a side gusset tube supply, denoted overall by 1, of a side gusset tube consisting of stretch film (= stretch film), which after its production is rolled up in a roll on an axis 2 for the purpose of appropriate storage, the outer circumference of the side gusset tube 1 a free end section 3 hangs down.

The gusseted tube consisting of stretch or stretch film is intended for the hood-like wrapping of piece goods stacks 4, of which a piece goods piece is shown in FIGS. 1 to 3.

As can be seen in particular from Fig. 1, the web width b of the gusseted hose 1 or 3 is essentially the same as the width B of the stack 4, the term "width" being defined above, namely the web width b Side gusseted hose 3 99.5% of the width B of the piece goods stack 4, with which they in is substantially the same size.

Since the free end section 3 of the gusseted tube is to be provided with a transverse seam 6 (see FIG. 6) behind it to form a hood before stretching or stretching at a distance from its free end 5 (by welding by means of welding jaws not shown) Which of the sections of the gusseted tube which form a hood after the transverse seam 6 is then cut off, the length L (see FIG. 6) of the free end section 3 of the gusseted tube in the not yet stretched state is practically substantially the same as the width B of the piece goods stack 4 (namely only 0.5% smaller).

It makes sense to have spreading fingers 7 (at least) on the lower end section of the free end section 3 of the gusseted tube (ie adjacent to the free end 5) engaging in the gusseted tube before the transverse seam 6 is placed (at least before the hood formed by the transverse seam 6 is cut off), in order to be able to handle it optimally during the hood formation and in particular the pulling-on process.

In the exemplary embodiment shown, the spreading fingers 7 engaging from the lower end of the free end section 3 of the gusseted tube are initially only moved in the y direction perpendicular to the plane of the gusseted tube 1 or 3 which has not yet been unfolded (see intermediate state according to FIG. 5). 6 until the complete unfolded state according to FIG. 6 (sd solid lines) is reached, in which the side gusseted tube is not yet stretched or stretched. Of course, the side gusseted tube (as can be clearly seen from FIG. 6) has a smaller circumference than the piece goods stack 4 to be wrapped. With a width measured in the x direction B and a depth A measured in the y direction, the circumference U₄ of the piece goods stack 4 is thus 2 x (B + A), while the circumference U₃ = 2 x (b + 2a) if (according to FIG. 5) with a each denote the leg length of the V-shaped folds. The relationship b + 2a <B + A therefore applies.

According to the stretch film wrapping process, the hood 3 'formed in each case from the free end section 3 of the gusseted tube after the transverse seam 6 has been placed and this section has been separated from the supply 1 (= stretched). For this purpose, the spreading fingers 7 according to FIG. 6 move diagonally outward to the coordinates x and y and then bring the hood 3 '- in relation to the dimensions of the piece goods stack 4 - to an oversize, indicated by dash-dotted lines in FIG. 6, which is so is dimensioned so that the hood 3 'can then be pulled over the piece goods stack 4 without difficulty.

From Fig. 6 it can also be seen that the transverse seam 6 formed by welding in the unstretched state has a length which corresponds essentially to the width B of the stack 4. The transverse seam 6 is of course also stretched accordingly when stretching (according to FIG. 6), but after the hood 3 'has fitted tightly to the piece goods stack 4 after the covering, the transverse seam 6 again takes on the practical dimension that the transverse seam 6 before the stretching process, ie it is free from harmful tensions in the sense of the above statements, so that there are no harmful effects on the wrapping of the loading unit thus formed. Rather, the conditions are such that the stresses occur essentially perpendicular to the transverse seam 6 formed by welding (and no longer, as previously, at any or random angles to the transverse seam 6), in particular in the V-shaped double regions of the film Overstretching can no longer occur, such that greater stresses occur in the film below than in the upper film section. Rather, in the case of the configuration of the side-gusseted hose according to the invention in relation to the piece goods to be encased, the inner film tensions in the upper film section are greater than in the lower one (which can thereby become largely free of tension), so that the lower film sections in the V- Form the double area easily under the tension of the upper film sections on the piece goods stack 4 and the tensioned upper film sections ensure a smooth surface, as this is highly desirable.

• b - Bahnbreite (von 1)
• B - Breite (von 4)

It should again be expressly pointed out that the supply or feed web width b of the gusseted tube 3 in no way needs to be substantially equal to the width B of the piece goods stack 4 to be wrapped in order to achieve this effect, but that this highly advantageous effect also then is achieved if the supply or feed web width b is approximately up to 95% of the width B of the piece goods 4 to be wrapped. Of course, the circumstances when dimensioning the web width b of, for example, about 94.2% of the width B of the piece goods 4 to be wrapped are also (considerably) better than in the prior art, but the range can be delimited with the information above which the present invention (still) comes to its fullest.

• b - web width (from 1)
• B - width (of 4)

REFERENCE SIGN LIST (LIST OF REFERENCE NUMERALS)

• 1 gusseted hose stock
• 2 axis
• 3 free end section (of 1) 3 'hood
• 4 general cargo stacks
• 5 free end (of 3)
• 6 cross seam
• 7 spreading fingers

Claims (2)

Side gusseted hose made of stretch film (= stretch film) for the hood-like wrapping of piece goods, in particular piece goods stacks, which has a smaller circumference than the piece goods to be wrapped, and whose free end section is provided with a transverse seam at a distance from its free end before stretching (= stretching), behind which the section forming a hood is to be separated, characterized in that the supply bsw. Feed web width (b) of the gusseted tube (3) at least about 95% of the width (b) of the piece goods (4) to be wrapped. Side gusseted tube according to claim 1, characterized in that the supply or feed web width (b) of the side gusseted tube (3) is substantially equal to the width (B) of the piece goods (4) to be wrapped.

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