EP1963187B1 - Hood packaging installation with device for producing side folds - Google Patents

Abstract

The method involves folding flat hose in v-shape, after final removal from the supply and before closing the outer sides. The two film webs do not lie, respectively, directly one on top of the other during the closing in the region of the outer side of the tube and at the level of the closure location, but with the inclusion of a v-shaped film fold extending with the tip of the fold towards the middle of the tube. The closing takes place in such a manner that the v-shaped folds and the areas of the film webs directly surrounding them are fixed relative to each other in the closing area. An independent claim is included for the device for packing articles e.g. palleted stack of goods.

Description

The invention relates to a method and a device for packaging a stack of goods according to the preamble of claim 1 (method) or of claim 7 (device).

Generic packaging systems work either after the so-called. Hood shrinkage process or after the so-called. Hood stretch process. In both cases, a foil hood is pulled over the objects to be packed (usually from above). In the case of a hood shrinking process, the film hood is then brought to heat shrinkage by heat. She pulls herself together and holds the stack together. In the case of the hood stretching method, the hood is stretched elastically, before and optionally during the coating, horizontally and / or vertically. Due to this, it lays under pretension against the stack to be packaged and holds it together.

A device operating according to the so-called hood shrinking method is known, for example, from US Pat DE 32 42 677 C2 known. The known system is equipped with a horizontal shrink frame, which is vertically movable along a stand. The shrink frame is designed such that it can be packed with a roughly box-like or parallelepiped stack. The film is in the form of a tube and comes from an endless supply roll at the back of the device. From there, the hose is guided over rollers or slide rails upwards over the device and into a bracket which ends above the shrink frame. As a rule, devices for cutting off and welding the hose together are provided in the console. In general, the console also includes a pair of rollers, via which the film feed to the machine is controlled by the rollers specify the peeling speed, with which the hose is withdrawn from its supply roll. The device comprises suction boxes for opening the tube. If the next tube to be opened, then the suction boxes are moved up to the film of the hose. The two superimposed film sections are each sucked by the suction box assigned to them and thus opened. The film hood is then welded up and cut off, then over pulled the stack or now completely pulled over the stack. Thereafter, the shrinkage of the film.

The film tube used by this system for producing the packaging hoods is a gusseted tube prefabricated by the film manufacturer and then wound into a supply roll, d. H. around a flat folded tube, which in its folded state along its two sides has V-shaped folds - such that the two film webs forming the main surfaces of the film tube not immediately in the region of the outer sides of the tube, but each including a V-shaped, lying with the pleat tip to the middle of the tube extending film fold each other.

Gusseted tubes are relatively expensive because of their special pretreatment with the film manufacturer. In addition, gusseted tubing on the supply roll is relatively thick, such that only a smaller number of running meters (about 50%) of gusseted tubing is to be accommodated on a supply roll having a maximum machine diameter as compared to the number of running meters that fit such a supply roll. when a flat hose is wound up. - A flat tube, which consists of two integrally connected one behind the other film webs, which are folded only once at their edges by 180 degrees and thus lie flat on the entire width.

There are therefore also known machines that process so-called flat tubes instead of the ready-made gusseted tubes. As long as no special measures are taken, results in the processing of flat tubes to film hoods the problem that protrude after covering the film hood on the packaged stack at the top of two lobes-shaped hood sections. This problem of earing is by the WO 02/068268 A1 in Fig. 1 clearly illustrated. It has been known for almost 40 years, cf. such as the old German publication DE 15 86 456 ,

These jagged protruding hood sections are visually unattractive. They also affect the packaging result in technical terms. The jagged hood sections are easily pinched or damaged due to their protrusion during transport-related handling of the load (eg stacking of individual loads). As a result, the moisture protection of the packaging is impaired. If such a hood is designed as a shrink-film hood, it may be that the protruding corners in the course of the made for the purpose of shrinking Heating up to be very soft. Under certain circumstances, they come too close to the heat source used for shrinking because of their distance and are overheated. Anyway, they at least collapse and come in sticky doughy state in contact with surrounding film areas. Under certain circumstances, then melt several layers of film together. Where different film layers are fused together, the resulting thicker film layer develops extreme shrinkage forces. It can then happen that the film is pulled thin at the transition between the regular layer and the layers glued together, ie at the end there has a local thin point and under the influence of transport-related forces breaks at some point.

Even when using such a hood as a stretch film hood disadvantages. Because in the area of the corner, the film u. U. inadmissible loose.

To avoid the annoying tip of the film hood, the beats WO 02/068268 A1 to "post-treat" the already packed load. For this purpose, the initially protruding lobes are to be inserted by means of special insertion elements between the cargo and the regularly fitting film. Such insertion requires a relatively "long-stroke" movement and costs valuable cycle time. It thus reduces the operating speed of the system. In addition, this insertion is a source of possible interference, especially at high clock frequencies. This is because the (fast) widening of one film section and the insertion of another film section must take place when the film has already been pulled over the charge and therefore already more or less tensioned. There is therefore a considerable risk that the film tears in the widened area. However, foil breaks are to be avoided as far as possible. Because they may lead to the fact that the system goes to fault and switches off.

From the JP 53-65191 A method and an apparatus according to the preambles of claims 1 and 7 show, in which a film is unwound from a supply of film and then expanded. Then the film is folded in laterally and welded at closure sites. In this state, the film is mounted on a stack, wherein the film is cut after mounting above the closure point.

In view of this, it is an object of the invention to provide a Verpackungsverfahreri or to create a packaging system that makes use of the machine-internal production of the film hoods of a flat hose, but the packaging when produced with flat-tube hoods typically occurring, annoying earing the finished hood avoids and waives an unwanted after-treatment of the pulled over the stack of goods to eliminate Zipfel.

This object is achieved by a method having the features of claim 1 and a device having the features of claim 7. Advantageous developments of the invention are the subject of the dependent claims.

The hose used in the form of a flat hose is folded in such a V-shape only after the final removal from its stock, and before closing, from its outer sides, the two film webs in the region of the outer sides of the hose and at the level of the closure point during the Closing in each case no longer directly, but with the inclusion of a V-shaped, with the pleat tip to the tube center extending towards film folds lie on each other and wherein the closure is such that the V-shaped folds and immediately surrounding areas of the film web in the closure area relative to each other be fixed. In carrying out the method, a device having the features of claim 7 is used.

In this way, the hose in the area in which it is sealed later, neatly folded before closing. The folded-in areas of the film, which would otherwise be superfluous and would have led to earing, are fixed in the course of closing the tube. In the subsequent (possibly only completing) coating it comes in this way from the outset not only to a Zipfelbildung. The subsequent removal of corners is eliminated.

One of the key advantages of this is that the method of making the hood of a flat hose uses. Because simple flat hose is much cheaper than prefabricated gusseted hose and also more flexible - the application range of a prefabricated gusseted hose is limited by the preselected size of the gussets. Nevertheless, despite the use of a flat hose no compromise on the quality of the finished packaging must be accepted.

There are also advantages in terms of the number of load units to be packaged per hour. Since on a roll whose maximum dimensions are fixed, significantly more running meter flat hose are wound, the intervals in which the packaging process for the purpose of inserting a new roll of film must be shut down, about 50% smaller. Now you put the required V-shaped Folding over the entire hose length in the continuous process (usually without any additional movement is necessary) results in a clear time advantage. The same applies if only local wrinkles are set and it is dispensed with an additional local mounting of the hose. Even if the additional movement "pulling and unfolding the hose locally" is carried out in order to create particularly precise wrinkles, there is usually a certain time advantage on balance.

In order to place precision folds, the tube is opened at its corresponding height prior to folding in such a way that it forms an approximately quadrangular tube cross section there. Then, by means of suitable folding members, the film is guided on two opposite sides of this roughly quadrangular tube cross-section in a V-shape towards the middle of the tube. Then, the tube cross-section is reduced, so that on the sides, which are guided inwards, each with its tip to the center of the tube cross-section facing V-shaped fold between the other two the hose cross-section bounding sides sets.

In this way, it is very easy, especially V-shaped folds in the form of a simple "V" precise and trouble-free to lay - the term V-shaped is functional to understand and describes the principle of the fold. For example, a V-shaped fold may also take the form of a double V, d. H. two concertina-shaped juxtaposed "VV" have. However, a V-shaped fold in the form of a simple "V" is preferred. Such a fold is by far the easiest and most reliable. It goes without saying that the "V" of the V-shaped fold has almost parallel pressed legs, as soon as the film tube after folding is possibly completely temporarily folded flat again - about fed to the section of the machine about more transport or guide rollers in which the closing, separating, etc. takes place.

The sides of the tube cross-section, which are not guided inwardly to form a V-shaped fold, are moved towards one another. In this way, it is very easy to maintain a controlled film tension during the laying of the V-shaped pleats, so that clean pleats are laid without the risk of overstressing the film.

The size of the two V-shaped pleats (ie the distance between the top of the V and the end of the two legs of the V) is adjusted by adjusting the length of the two sides of the tube cross-section which are moved towards each other when the V-shaped pleats are laid to pick up the V-shaped folds between them Beginning of folding is chosen accordingly. In this way, it is possible to adjust the size of the gussets and thus the size of the film hood ideally to the contour of each charge to be packaged. For while virtually ideal parallelepipedic charges require virtually no or only relatively small V-shaped folds, it is necessary to provide relatively large V-shaped folds in the case of cargoes of significantly rectangular cross-section that deviate greatly from the square cross-section in order to avoid earing. A size of the V-shaped folds chosen as well as possible is particularly important for the tear strength or durability of the hood in the closure area. Namely, the V-shaped folds are not dimensioned correctly, then occur z. B. in the hood closing the weld at the point of transition from four to two layers significantly tensile forces. These lead to tears, possibly even to the complete rupture of the film hood. This danger is especially true in stretch film hoods. It is at least in the approach but also recorded where the hood is shrunk in the area of a badly fitting after the coating and thus exposed to stress weld.

On the device side, the specified object is achieved by the device according to claim 7.

Fig. 1 bis 5

eine als solche bekannte Einrichtung zum Öffnen eines Folienschlauchs mittels Foliengreifern;

Fig. 6a

eine Aufsicht auf die als solche bekannte Einrichtung zum Öffnen der Folienhaube in dem Moment, in dem die Faltorgane gemäß eines ersten Ausführungsbeispiels in Wirkung zu treten beginnen;

Fig. 6b

die von Fig. 6a gezeigte Anordnung in Seitenansicht;

Fig. 7a

das Zusammenwirken der von Fig. 6a und 6b gezeigten Foliengreifer und Faltorgane in einem fortgeschrittenen Stadium des Einfaltens zweier Seiten des Folienschlauchs;

Fig. 7b

die von Fig. 7a gezeigte Anordnung in Seitenansicht;

Fig. 8a

das Zusammenwirken der von den Fig. 6a und 6b gezeigten Foliengreifer und Faltorgane, nachdem die Falten vollständig gelegt wurden und die Folienhaube in Abziehrichtung gesehen vor (oberhalb) den Foliengreifern und den Faltorganen zugeschweißt und abgetrennt wird;

Fig. 8b

die von Fig. 8a gezeigte Anordnung in Seitenansicht;

Fig. 9

die Foliengreifer und Faltorgane der ersten Ausführungsform in einer Variante, bei der die Foliengreifer zweiachsig in der Horizontalebene verfahrbar sind um so die Größe der V-förmigen Falten einstellen zu können und hier so verfahren wurden, dass kleine V-förmige Falten gelegt werden;

Fig. 10

die von Fig. 9 gezeigten Foliengreifer und Faltorgane, wobei die Foliengreifer hier so positioniert wurden, dass große V-förmige Falten gelegt werden;

Fig. 11

ein zweite Ausführungsform bei der die Falten zur Realisierung höherer Taktzeiten in den Dachabschnitt des Folienschlauches gelegt werden;

Fig. 12

eine teilgeschnittene Aufsicht auf die von Fig. 11 gezeigte zweite Ausführungsform;

Fig. 13

eine dritte Ausführungsform, die es ermöglicht die falten im Durchlaufverfahren zu legen, allerdings in einer Position, bevor die Faltplatten zugestellt wurden um so auf den Schlauch einzuwirken;

Fig. 14

die dritte Ausführungsform zu Schichtbeginn oder nach Wechsel der Vorratsrolle für den Folienschlauch;

Fig. 15

Anlagenschema zur Realisierung der dritten Ausführungsform.

Further advantages, features and details will become apparent in the following detailed description of an embodiment with reference to the accompanying drawings. The Figures 11-15 as well as the associated description serve solely to explain the background of the invention and are not the subject of a claim. The drawings show purely schematically the following:

Fig. 1 to 5

a device known as such for opening a film tube by means of film grippers;

Fig. 6a

a plan view of the known as such means for opening the film hood at the moment in which the folding members according to a first embodiment begin to take effect;

Fig. 6b

the of Fig. 6a arrangement shown in side view;

Fig. 7a

the interaction of the Fig. 6a and 6b shown film gripper and Faltorgane in an advanced stage of Einfalts two sides of the film tube;

Fig. 7b

the of Fig. 7a arrangement shown in side view;

Fig. 8a

the interaction of the Fig. 6a and 6b shown film gripper and Faltorgane after the wrinkles have been completely laid and the film hood in Abziehrichtung seen before (above) the film grippers and the Faltorganen welded and separated;

Fig. 8b

the of Fig. 8a arrangement shown in side view;

Fig. 9

the film gripper and Faltorgane the first embodiment in a variant in which the film gripper are biaxially movable in the horizontal plane so as to be able to adjust the size of the V-shaped folds and have been moved so that small V-shaped folds are placed;

Fig. 10

the of Fig. 9 shown film gripper and Faltorgane, the film gripper have been positioned here so that large V-shaped folds are placed;

Fig. 11

a second embodiment in which the folds are placed in the roof portion of the film tube to realize higher cycle times;

Fig. 12

a partially cut top view of the Fig. 11 shown second embodiment;

Fig. 13

a third embodiment, which allows the folds to be laid in a continuous process, but in a position before the folding plates were delivered so as to act on the tube;

Fig. 14

the third embodiment at the beginning of the shift or after changing the supply roll for the film tube;

Fig. 15

Plant schematic for the realization of the third embodiment.

For all embodiments described below applies that the packaging system and its basic components can be arranged approximately as from the Fig. 1 of the DE 32 42 677 C2 , which is hereby incorporated by reference. If the packaging system is designed as a shrink system, it will have the shrink frame shown there. Otherwise it will they are equipped, for example, with a reef frame for meeting, transverse stretching and vertical stretching of the film hood (the vertical stretch takes place during the coating in which the removal of the film from the reforgants is controlled "braked").

The means for laying the V-shaped folds, which essentially consist of the film grippers to be described in more detail below and the folding members associated therewith, are in the first two embodiments, as seen in the removal direction of the film tube, behind the feed rollers 13 (which are in the case of FIG DE 32 42 677 C2 integrated into the console 5), above the height of the largest charge to be packed. In the third embodiment, the means for laying the V-shaped folds in Abziehrichtung the film tube are seen before the (last) feed rollers mounted. In Fig. 6b and the other in a corresponding manner, the two first embodiments showing figures carry the feed rollers the reference numeral thirteenth

The film tube is either open at the time discussed here (on the basis of the figures) and at least partially pulled over the load. Alternatively, it is, for example, when the plant is designed to carry out a hood stretching process, aufgerefft at this time on the Refforgane. In both cases, the upper end of the film tube at the time to be considered here is still connected to the stored flat hose.

The film grippers are now moved in the horizontal direction so far that they (as seen in the stripping) come to rest just behind the later to form a film hood to be closed section of the film tube film hood. The film tube is still at least almost unopened at this point, d. H. the two film webs forming the flat film tube lie flat against each other.

The film grippers are constructed in principle, as from the DE 43 26 827 A1 known, which is hereby made the subject of the description.

Each of the film grippers (2, 4) consists of a suction box 4, which carries a suction / gripping element 2. Each suction box has a suction surface 3 on its side facing the film. The latter consists approximately of a corresponding opening, which is covered with a grid. The suction gripping element 2 is pivotally hinged to the suction box 4.

As soon as the four suction boxes 4 of the film grippers have been brought into contact with the films, vacuum is applied by switching on the corresponding suction fan that the film webs A, B are pressed in sections on the suction surfaces 3. The Fig. 1 shows a snapshot of this situation.

Then the film grippers are moved apart in pairs in a horizontal direction. Each of the film gripper takes with the pressed onto the suction surface 3 of its suction box 4 film, so that the film tube is opened to a, initially small, enclosed between the film webs A, B cross-section, as the Fig. 2 shows.

Then the respective pivotally mounted on the suction boxes 4 suction gripping elements 2 are folded away at an angle of preferably <90 ° from the film. They thereby also release a suction opening at the respective outwardly facing end face of the relevant suction box 4. The sections of the film webs A, B projecting outwardly beyond the cross-section bounded by the four film grippers are thereby sucked in by the released end faces of the suction boxes 4. Thus, the film gets into the region of the gap, which has opened by the pivoting back of the suction gripper elements 2 between them and the end faces of the suction boxes 4, see. Fig. 3 , The suction gripper elements 2 are now swung back into their original position and come so on the front sides of the suction boxes 4 to the plant. As a result, each of the applied to the outwardly facing end side of the suction box film section is clamped. The hitherto only opened to a small cross-section film tube is now no longer held by the suction, but primarily "gripped" in that it is clamped a four digits, as the Fig. 4 shows.

Subsequently, the film grippers are moved in pairs in the horizontal direction further apart, so that flat hose is now open to a roughly quadrangular cross section, as well as from Fig. 5 shown.

Up to this point, the handling of the film tube in principle corresponds approximately to that of the DE 43 26 827 A1 proposed handling - but with the difference that here no prefabricated gusseted hose is opened, but a simple, cost-effective and in production considerable flexibility flat hose.

At those pages C, D, which is not acted upon substantially directly by the film gripper, the folding members are now approached by advancing in approximately horizontal direction. The folding members are here designed as narrow and elongated perpendicular to the plane extending folding plates 14. The Fig. 6b shows this in one Side view, the Fig. 6a in a view from above along that sectional plane AA, the in Fig. 6b is marked.

The folding plates 14 are now moved further horizontally in the direction of the tube center of the approximately stretched to the square film tube. In this way, they fold the film tube, which has hitherto been opened approximately into a quadrilateral, from two of its outer sides C, D in the direction of the center of the hood M into a V shape. During this Einfaltens the film gripper are moved towards each other in pairs in the horizontal direction, so that the voltage of the folding plates 14 V-shaped folded sides of the film tube is kept controlled, or in any case overstretching of the film is prevented. This process shows the Fig. 7b Seen from the side or the Fig. 7a seen from above, in Fig. 7b by AA marked cutting plane.

The Fig. 8a and 8b finally show (each seen from the same point of view, as the previously discussed Fig. 6a and 6b or 7a and 7b) the position in which the two V-shaped folds are completely laid. Is it the case now that the flat film tube previously clamped to form a quadrangle is folded in a V shape from its outer sides C, D which formerly had a 180 ° fold. in such a way that the two held by the suction boxes 4 and the suction / gripping means 2, opposing wide film webs A, B in the region of the outer sides of the hose no longer directly, but each including a V-shaped, with the Wrinkle tip to the tube center extending film folder lie on each other. This V-shaped fold is not only in the area of the film gripper 2, 4, but extends at least upwards into the area, which is to be subsequently closed, ie at the height of the subsequent closure point.

Now what the Fig. 8b shows, the closing device 15 is activated. In principle, the closing in various ways, such. B. by folding and / or stapling done. Ideally, however, a weld is pulled, which extends meaningfully over the entire width of the film tube away, but this is not mandatory. No matter in which way the closure takes place, it is always closed so that the V-shaped folds and the immediate surrounding areas of the film webs A, B are fixed relative to each other. In this way it is prevented that the V-shaped film folds in the area of the closed position of the hose to rise again.

Then the hose, as seen in the stripping, separated from the rest of the hose supply before the closing device. For example, in which about a horizontally guided blade 16 cuts through the hose. Alternatively, a hot wire can be used.

Now the finished film hood can be covered over the charge or the already started coating of the film can be completed.

Advantageously, the film grippers 2, 4 are designed and moved such that they can be used both to open, as seen in Abziehhrichtung, the extreme end of the hood and make the hood ready to cover, as well as serve the hood at the height the later closure point (just below) to open and so in cooperation with the Faltorganen 14 to accomplish the folding.

It should also be emphasized that in the first exemplary embodiment described here, only locally in the region of the later closure point are V-shaped folds laid. This protects the film and protects against unnecessary film tears that stop the entire process. Because it is not necessary to put over the entire length of the later film hood away V-shaped folds. This is because the latter, outside the vicinity of the closing point, are pulled up again when the hood is pulled over the load. The reason for this is that, outside the vicinity of the closure, as a rule, the entire film cross-section is needed in order to envelop the charge to be packaged.

Forming the film grippers 2, 4 so that they can move in pairs in a first horizontal direction toward and away from each other and in pairs (but in a different pairing) in a second horizontal direction, orthogonal to the first horizontal direction, towards and away from each other can drive away, then can be set in a very simple manner, the desired size, which receive the V-shaped folds in their laying. In this way it is possible, in individual adaptation to the cross section of each load to be packaged, to place V-shaped folds of optimal size so that the foil hood produced for this load to be individually packaged optimally "sits" on the load.

The FIGS. 9 and 10 illustrate this. While the Fig. 9 shows how relatively small V-shaped folds are formed, the shows Fig. 10 the formation of relatively large V-shaped folds.

For this purpose, the film gripper from the position they were previously in folding under the Fig. 9 had engaged each other before folding the folds for the next hood along arrows E, Fig. 10 , The sides A, B of the film hood which are grasped and held by the suction boxes 4 or the suction / gripping devices 2 are now shorter. Accordingly, the V-shaped folds can be pulled deeper from the now longer sides C, D forth inwardly towards the middle of the tube, in which the folding plates 14 are further retracted accordingly in the direction of the hood center M.

In the same way, by corresponding pairwise moving apart of the film gripper along the axes indicated by the arrows E and film hoods can be made with smaller V-shaped folds.

The film tension is controlled in both cases, as described above, by a yielding in the direction of the arrows FL.

Such a design of the film gripper 2, 4 also makes it possible to process flat tubes, which have different widths of their own. This ensures a high degree of flexibility. Because not all cases can be achieved with a flat tube one and the same width only on the variation of the wrinkle size optimal results.

The variability in terms of the size of the V-shaped folds brings significant benefits. Where previously either the rolls of film had to be changed, or machines that could store different films and put them on call were required, today a machine with a single supply of film is sufficient. As a result, not only the mechanical complexity is smaller and the quality of the finished packaging higher. Rather, the clock speed increases. And even then, even if the loads to be packaged always have very different dimensions. Because a conversion of the machine (even if it may be automatically possible) is unnecessary in each case. As soon as the charge sensors have detected the cross-section of the charge now to be packed in each case, they send a corresponding signal to the machine control, which in turn calculates the required size of the V-shaped folds and then takes the necessary precautions - such as the pairwise movement of the foil grippers along the arrows "E" and "FL" in the required position. The result is a biaxial motion - projected onto a two-axis coordinate system lying horizontally in space. The folding organs are controlled appropriately.

A second embodiment, operating in a similar manner as the first embodiment, show the Fig. 11 and 12 , This embodiment avoids it to open the film tube for the purpose of folding at a place other than its end of the hose in addition to lay there the wrinkles.

In this embodiment, the film tube is opened after passing through the film feed rollers 13 and aufgerfft in a known manner to a puller 19 for the subsequent hood. Thereupon, an approximately roof-shaped cross-sectional profile (roof section 12 *) is formed between the opened-up section of the film tube and the still unopened section of the film tube. In this already open area of the film tube and the wrinkles are placed. For this purpose, just above the coating device 19, wedge-shaped folding elements 18 are pressed into the roof section 12 * from two sides, forcing it to have a V-shaped bend inwards. The position of the folding mechanism 18 and the still unfolded film area in Fig. 12 shown in dashed lines. Subsequently, the devices 15 provided here in the form of sealing bars for closing the film tube are brought together. They take the foil of the roof section 12 * with them, compress them inwards and also grasp the two V-shaped inward creases of the foil, which are thereby placed in each case into a V-shaped fold. Then it is welded. The V-shaped folds are welded to the film in contact with them and thus fixed. The film hood is then cut off by means of a knife 20 running along the welding bar. The finished film hood can now be stretched as usual and covered or pulled over and shrunk. The folding members 18 are here wedge-shaped with an inwardly directed towards the center of the film tube tip. This favors the V-shaped inward buckling of the film. Ideally, the acute angle "W" between 55 and 85 ° and can be adjusted if necessary, so it is adjustable, for example, depending on film thickness and strength, which leads to a good buckling, without the film by a too large peak is significantly overloaded.

A third embodiment show the FIGS. 13 and 14 , In the context of this embodiment, it is provided that the flat tube during removal from its supply continuously (so to speak in a continuous process) to fold laterally - so that it is provided over its entire length with lateral V-shaped folds "VF" of the type in question here, before it enters the area of the machine in which the sealing of the film tube as well as the separation and coating of the hood takes place. The laying of the folds takes place with a hood stretch hood or hood shrinkage system which is unchanged from those described in the preceding exemplary embodiments, unless otherwise described below. In this case, two pairs of rollers 13a and 13b are now provided in this case. Preferably, each carries a roll of Roller pair 13a and 13b a soft, supple and thus well-sealing wear layer, while the other roller consists at its periphery of smooth, usually ground metal. They press from both sides with the necessary pressure on the film between them.

After each change of the film roll, the beginning of the new film tube between the pairs of rollers 13 a and 13 b is inserted. Then, the rollers of each pair of rollers are delivered against each other, so that the hose section B located between the two pairs of rollers 13a and 13b is practically completely sealed. The plant operator now injects, for. B. by piercing a corresponding nozzle 22a through the film, a certain amount of compressed air in the sealed tube section so that it forms a balloon. The injection hole is z. B. closed by an adhesive strip. The inflation of the tube section to be carried out in an inital manner can also be automated, but i. d. R. be made by the system operator to keep the equipment costs small. Because with a suitable selection of the lining and the contact pressure of the roller pairs 13a and 13b, the air losses will go to zero. The hose section B must then be inflated after each roll change only once, which is easy to accomplish by hand.

In particular, in systems that run because of their large film supply of a roll change to the next very long, it may be advisable, instead of the pair of rolls 13 b z. B. Rollendrilling 13b provide. It is crucial to intensify the contact between the rollers and the film at the sealing point by diversion and so to perfect the seal - so as not to have to stop in between the system for the purpose of refilling the balloon with compressed air. The Fig. 15 shows such a role twin top left. For other corresponding pairs of rollers (like 13b), the same applies. Also quadruple rolls etc. are possible.

Now, the folding wedges 14 are delivered from two sides, which press the balloon-like tube section B at least in regions from two sides inwards in a V-shape and for this purpose preferably form a funnel-shaped geometry between them, through which the balloon-like tube section tapers onto the roller pair 13b , In addition, guide surfaces 14a are additionally supplied to the foil balloon (here in a plane arranged approximately perpendicular thereto). These baffles 14a do not induce wrinkling, but prevent the balloon from undesirably evading or being undesirably deformed under the action of the folding wedges 14. The guide surfaces also preferably form a funnel-shaped geometry between them, through which the balloon-like hose section tapers onto the roller pair 13b. Then the Film feed approached, so that the film tube moves in the direction of the arrows V. The sides of the film tube slide along the now delivered folding wedges 14 and are "prefolded" by the folding wedges 14 continuously V-shaped (not explicitly shown). As soon as the tube pretreated in this way is pulled between the rollers of the roller pair 13b, its prefolded sections are folded up in a clean V-shape. The film tube entering the region between the roller pairs 13a and 13b as a flat tube thus leaves the region between the roller pairs 13a and 13b as gusseted tubing, ie is provided with V-shaped pleats "VF" - which, however, lie somewhat further inwards than they do in FIG Fig. 14 for the purpose of illustration are merely indicated, since the hose is so narrowed by the folding generally.

As far as here talk of delivery of the folding wedges 14 and the guide surfaces 14a, this is only a u. a. the film change facilitating option. Instead, guide surfaces and folding wedges may also be rigidly mounted or displaced only as required for adjustment purposes.

Although the rollers of the roller pairs (with the film between them) roll on each other, the trapped compressed air is not lost. Instead, it can be said that it is "pumped" into the region of the film tube by the rollers from the region of the film tube which is about to move out of the area between the roller pairs 13a and 13b between the rollers of the roller pair 13b. which enters via the rollers of the roller pair 13a for the first time in the area between the roller pairs 13a and 13b.

It should be noted only that the roller pairs 13a and 13b, unlike purely exemplary in the FIGS. 13 and 14 shown, as a rule, will not include a horizontal plane between them. As the Fig. 15 Instead, they are placed in the machine so as to enclose an approximately vertical plane - namely in the ascending region, in which the flat tube, after its removal from the supply in the machine, is led upwards and then from above as a hood over the to be pulled to be packed items, or, instead, in the descending region, in which the flat tube from the top coming down in the direction of the objects to be packaged is performed. The Fig. 15 illustrates these two alternatives summarized in one picture. In the left half of the picture is shown how the of the FIGS. 13 and 14 shown folding device (13a, 13b, 14, 14a) is housed in the ascending region of the machine. If the accommodation here, then the machine can be extremely compact, as otherwise used only with low intensity space is used and there (important in hood shrinking machines) of the blown and thus sensitive film section is kept outside the waste heat zone. Alternatively, the means for folding (13a ', 13b', 14, 14a ') can also be arranged in the descending region of the machine, in the vicinity of the charge to be packaged.

Claims (10)

1. Method of packaging articles, in particular palletized stacks, with a sheet-material cover, having the following steps:

   withdrawing a length of a flat flexible tube from a supply, the flat flexible tube comprising two webs of a single-piece sheet material which are each pleated externally and thus lie flatly, and directly, one upon the other over the entire width,

   opening the front end of the flexible tube, as seen in the withdrawal direction,

   at least partially closing the flexible-tube length withdrawn from the sheet-material supply essentially transversely to the withdrawal direction at a closure location remote from the front end of the flexible tube,

   severing the flexible tube from the rest of the flexible-tube supply at a location upstream of the closure location, as seen in the withdrawal direction,

   drawing the flexible tube over the articles which are to be packaged, preferably with the cover, or the flexible-tube portion which forms essentially at a subsequent point in time, being reefed onto a reefing device beforehand,

   wherein the flat flexible tube, following definitive withdrawal from its supply and prior to closure, is pleated in a V-shaped manner from its outer sides such that the two sheet-material webs (A, B) no longer lie directly one upon the other in each case in the region of the outer sides of the flexible tube, and

   level with the closure location, during closure; rather, they lie one upon the other with the inclusion of a V-shaped sheet-material pleat which has its tip extending in the direction of the centre (M) of the flexible tube,

   and wherein closure takes place such that the V-shaped pleats and those regions of the sheet-material webs which immediately surround the same are fixed relative to one another in the closure region,

   characterized in that

   the method is implemented by using an apparatus according to one of Claims 7 to 10.
2. Method according to Claim 1, characterized in that the cross section of the flexible tube is opened for the purpose of producing the V-shaped pleat and then, from two opposite sides (C, D), a portion of the sheet material which bounds the flexible-tube cross section is guided locally inwards, in the direction of the centre (M) of the flexible-tube cross section, whereupon the cross section of the flexible tube is essentially closed again.
3. Method according to Claim 2, characterized in that, prior to being pleated, the flexible tube is opened at the subsequent pleating location such that it forms an approximately quadrilateral flexible-tube cross section there, whereupon, by means of the pleating mechanisms (14), the sheet material, on two opposite sides of this flexible-tube cross section, is guided in a V-shaped manner in the direction of the centre (M) of the flexible tube and then the flexible-tube cross section is reduced in size, in which case the sides (C, D), which are guided inwards, establish themselves in each case as a V-shaped pleat, which has its tip oriented towards the centre of the flexible-tube cross section, between the two other sides (A, B) forming the flexible-tube cross section.
4. Method according to one of the preceding claims, characterized in that the flexible-tube cross section is reduced in size by virtue of the fact that the sides (A, B) of the flexible-tube cross section, these sides not being guided inwards for the purpose of forming a V-shaped pleat, are moved towards one another.
5. Method according to Claim 4, characterized in that the lengths of the sides (A, B) of the flexible-tube cross section, these sides being moved towards one another, are kept essentially constant.
6. Method according to one of the preceding claims, characterized in that the size of the V-shaped pleats is established in that the lengths of the two sides (A, B) of the flexible-tube cross section, these sides being moved towards one another as the V-shaped pleat is being produced, is selected correspondingly at the beginning of the operation of producing the pleats.
7. Apparatus for packaging articles, in particular palletized stacks, with a sheet-material cover, having means (13; 13a; 13b) for withdrawing and feeding a flat flexible tube made of packaging sheet material from a supply, having a gripping device (2, 4) which is formed from sheet-material grippers and is intended for opening the laid-flat flexible tube, having a sheet-material-closing device (15) for at least partially closing the flexible tube approximately transversely to its longitudinal axis, having a cutting device (16) for separating the flexible tube into individual portions, and having a drawing-over device (19) for drawing the required length of flexible tube over the articles which are to be packaged, wherein the apparatus comprises means (2, 4 and 14; 18) by way of which the flat flexible tube, following definitive withdrawal from its supply and prior to closure, is pleated in a V-shaped manner from the outer sides such that the two sheet-material webs (A, B), which were formerly laid flat to form the flat flexible tube, no longer lie directly one upon the other in the region of the outer sides of the flexible tube, and level with the closure location, during closure; rather, they lie one upon the other with the inclusion of a V-shaped sheet-material pleat which has its tip extending in the direction of the centre of the flexible tube, and the apparatus comprises further means, which close the flexible tube such that the V-shaped pleats and those regions of the sheet-material webs which immediately surround the same are fixed relative to one another at the closure location, characterized in that the means for pleating the flexible tube are arranged downstream of the flat-flexible-tube-withdrawing advancement rollers (13), as seen in the withdrawal direction of the flexible tube, and comprise the sheet-material grippers (2, 4), which grip the sheet material of the flat flexible tube and open the flat flexible tube to form an approximately quadrilateral cross section, and pleating mechanisms, (14; 18), which guide two opposite sides (C, D) of the approximately quadrilateral cross section in a V-shaped manner inwards, in the direction of the centre (M) of the flexible-tube cross section, wherein the sheet-material grippers (2, 4) are configured such that they grip the sheet material locally at at least four locations, and that the sheet-material grippers (2, 4) can be displaced relative to one another along two axes such that the positionally predetermined lengths of the longitudinal and transverse edges of the quadrilateral into which they open the sheet material when pleats are being produced can be varied relative to one another, in order thus to set the size of the V-shaped pleats.
8. Apparatus according to Claim 7, characterized in that the pleating mechanisms are configured as pleating bars or pleating plates (14; 18) which, for the purpose of producing pleats, are displaced in the direction of the centre (M) of the sheet-material cross section and are synchronized with the approximately simultaneous movement of the sheet-material grippers such that the latter pleat the two sides (C, D) of the sheet material inwards, in the form of a V, in a defined manner without overloading the sheet material.
9. Apparatus according to either of Claims 7 and 8, characterized in that the sheet-material grippers (2, 4), when pleats are being produced, are moved together until they butt against pleating bars or pleating plates (14), with the interposition of the pleated sheet material.
10. Apparatus according to Claim 9, characterized in that, during fixing of the V-shaped pleats and of those regions of the sheet-material webs which immediately surround the same, the pleating bars or pleating plates (14) are guided such that they remain between the sheet-material grippers (2, 4), and they are drawn back only once fixing has taken place.

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