EP2740673B1 - Method and device for applying a film to a stack of goods - Google Patents

Description

The invention relates to a method for applying a film to a stack, in particular for shrinking a film onto a stack, wherein the stack comprises at least one unit, wherein first a film band is placed over the circumference of the stack of goods adjoining sides of the stack, wherein the upper edges of the stack of material projecting supernatant portions of the film band are folded over the top of the stack and are preferably fixed there and then a Foliendeckblatt is placed on top of the stack, the Foliendeckblatt projecting with foil sections on the upper edges of the stack.

By the term good stack is meant in particular a plurality of packages, packages, sacks or the like units, which are preferably combined or stacked to form a rectangular stack of goods. It is within the scope of the invention that the stack is received on a pallet. Basically, however, good stacks can be used without a pallet. In principle, the stack of goods can also be only a few stacked units or even a single larger unit, for example from the white goods sector (washing machines, refrigerators, dishwashers and the like). It is further within the scope of the invention that the film is a plastic film and preferably a plastic shrink film which is heat-shrinkable under the influence of heat on the product stack. In this way, the stacked in the stack units are firmly held together and in particular secured against slipping or the like.

From practice, methods for applying a film to a stack in various embodiments are known. It is known, inter alia, in the paper industry due to the different charge formats of the stack of goods to make the packaging as follows. First, a Foliendeckblatt is placed on the top of the stack and this Foliendeckblatt is about the upper edges of the stack by about 100 to about 300 mm. Subsequently, a film band is placed around the sides of the stack, which encloses the protruding film sections of the folio cover sheet. The film band is usually with overhang sections with a width of 50 to 400 mm on the upper edges of the stack over. In a further step, the supernatant sections of the film band are then welded to the folio top sheet. According to another known procedure, the film band is first placed around the stack and folded with said protruding portions on the top of the stack and fixed there. Subsequently, the Foliendeckblatt is then placed and welded in a further step with the supernatant sections of the film band.

Both methods described above are characterized by disadvantages. The folded-over projecting portions of the film band are folded in three layers, in particular at the corners of the stack and therefore can heat only slowly or incompletely during the welding process. This results in leaking wrinkles and capillaries and this has the consequence that water can get from the side under the Foliendeckblatt. Above all, packaged paper products can thereby be treated with mold. Furthermore, air is also trapped between the foil cover sheet and the folded-over projecting portions of the foil band, so that a formation of bubbles occurs, which can rupture during stacking, so that even then water can penetrate.

Out US 3,667,598 A a method of the type mentioned is known. However, this method leaves something to be desired in terms of its reliability and freedom from interference. - A method for applying a film to a stack is further from WO 2007/048558 A1 known. In this method, first a foil cover sheet is placed on the stack and then in a further process step, a heat shrink film jacket is placed around the stack. This method has proven itself in principle. It is nonetheless capable of improvement.

In contrast, the invention, the technical problem underlying a method of the type mentioned above, with which the disadvantages described above can be reliably and effectively avoided.

To solve this technical problem, the invention teaches a method of the type mentioned above, which is characterized in that then a press plate is pressed onto the top of the stack or on the lying on it Foliendeckblatt that subsequently hot air is generated at the sides of the stack, wherein the hot air rises along the sides of the stack and heats the projecting film sections of the Foliendeckblattes with the proviso that the film sections are welded to the voltage applied to the sides of the stack or in the top of the stack of goods foil band, the first at the upper edges of the Good stack hanging film sections are raised by means of the rising hot air, fall back as a result of this takes place heating back to the sides of the stack and weld there with heated Banderolenabschnitten. - Preferably, the stack is a cuboid stack with four sides, a top and a floor. The foil band is then placed around the four sides of the block-shaped stack of goods.

It is within the scope of the invention that the foil band and the foil cover are made of thermoplastic material. It is also within the scope of the invention that a shrinkage of the film band takes place on the stack under heat. In the film band can be a film section, which is placed around the sides of the stack and at its two ends connected to each other, preferably welded. According to another embodiment, however, the foil band may also be a foil tube or a foil hood, which is pulled over the stack.

It is within the scope of the invention that the protruding portions of the film band and / or the foil sections of the folio cover sheet are present over the circumference of the stack or circulate over the circumference of the stack. Advantageously, the width b of the protrusion sections is 50 to 400 mm, and preferably the width B of the protruding film sections of the folio cover sheet is 100 to 300 mm. As far as with respect to the Foliendeckblattes of the above film sections is mentioned, this means within the scope of the invention also that the film sections can hang down on the sides of the stack of goods.

Preferably, within the scope of the invention, a heated or tempered press plate is used. It is recommended that the press plate is heated or tempered to a temperature which is below the melting temperature of the material or the plastic of the Foliendeckblattes. Conveniently, only a preheating of the folio cover sheet should be realized with the help of the pressed-press plate. - According to preferred According to an embodiment of the invention, the pressing plate is pressed onto the folio cover sheet with the proviso that air is pressed out or pressed out of the folded-over protrusion sections of the foil band and / or air between the protrusion sections and the folio cover sheet. In this way, the disadvantageous air inclusions described above can be avoided at the top of the stack. Such air inclusions can occur especially at the corners of the stack, where the supernatant sections are usually folded in three layers or are folded onto the top.

It is recommended to work with a press plate which projects with press plate sections over the upper edges of the stack. Appropriately, it is horizontal or substantially horizontal projections or protruding press plate sections. The press plate then has a larger area than the top of the stack. It is recommended that the press plate has a larger area than the lying on the top of the stack of material Foliendeckblatt. In principle, the surface of the pressing plate can also correspond to the surface of the folio cover sheet. A particularly preferred embodiment of the invention is characterized in that the pressing plate forms the top or the ceiling of a shrinking chamber, wherein the shrinking chamber has side walls extending along the sides or along the lateral surfaces of the stack and wherein the hot air passes through the shrinking chamber Direction of the top of the stack or in the direction of pressure plate is passed. It is within the scope of the invention that the press plate forms the upper end of the shrinking chamber in the pressed-on to the top of the stack of goods condition. It is also within the scope of the invention that shrinking chamber sections of the shrinking chamber are arranged distributed over the circumference of the stack of goods. According to a recommended embodiment of the invention, the side walls of the Shrinking chamber of vertically telescopic side wall sections. Then, the vertical extent of the side walls can be easily adapted to the height of the stack. Conveniently, upper sidewall portions of the vertically telescoping sidewall portions abut the press plate.

It is within the scope of the invention that upper banderole sections of the film banderole are heated with the rising hot air, so that these heated banderole sections can be welded to the heated film sections of the folio cover sheet. Conveniently, therefore, a simultaneous heating or heating takes place both the film sections of the Foliendeckblattes and the Banderolenabschnitte in the upper region of the stack. In this way, an optimally tight or watertight welding between foil cover sheet and foil band can be achieved.

According to the invention, the first hanging down on the upper edges of the stack of goods film sections are raised by the rising hot air and fall back as a result of taking place thereby heating back to the sides of the stack and are there welded to the heated Banderolenabschnitten. The raised film sections thus lose stability due to the heating and therefore fall back to the sides of the stack, where they can be welded to the heated upper Banderolenabschnitten. - The invention is based on the finding that by the rising hot air, a negative pressure at the top of the edges of the raised Foliendeckblattes is generated. This negative pressure causes the film sections remain relatively long in the raised position and can be effectively heated there. When heating or heating of the film sections, the sections pull together in the direction of stack. Due to this shrinking effect, this changes Area / weight ratio of the sections. Nevertheless, due to the generated negative pressure, the film sections still remain in the raised position until they become, as it were, "doughy" and fall back to the sides of the stack due to their lack of stability, where they are welded to the likewise heated banderole sections.

It is within the scope of the invention that the rising on the sides of the stack of hot air is generated with a surrounding the sides of the stack of hot air shrink frame. The hot air shrink frame is expediently moved vertically into a position in which the hot air rising from the hot air shrink frame can effectively heat the foil sections of the folio cover sheet or the upper band sections for welding. It is also within the scope of the invention that the hot-air shrink frame is arranged with sufficient horizontal distance or horizontal safety distance to the sides of the stack. It is also within the scope of the invention that the film band is shrunk with the hot air shrink frame on the stack or on the sides of the stack of goods. In this shrinking on the sides of the stack of goods is also called the so-called "side shrink".

Empfohlenermaßen the hot air-shrink frame is moved after the heating of the protruding film sections of the Foliendeckblattes or after the heating of the upper banderole sections along the sides of the stack of goods down. Appropriately, the Heißlt-chrumpfrahmen is thereby shut down so fast that remaining air is forced out of the space between the film band and stack of goods downwards. It is recommended that subsequently a bottom foil of the stack is welded to the foil band by means of the hot air shrink frame. It is within the scope of the invention that this bottom sheet is arranged between the pallet and the stack. The welding of the foil band with the bottom foil is also referred to as a "bottom shrinkage".

An alternative embodiment of the invention provides that the position of the hot-air shrink frame for the "under-shrinking" or for welding the bottom film with the film band and the position of the shrink frame for the production of hot air for lifting the Foliendeckblattes or for welding the film sections This embodiment is particularly recommended for stacks with low height.

A particularly well-proven embodiment of the invention is characterized in that the press plate is raised during the shrink-wrapping of the film band to the sides of the stack (side shrink) or during welding of the film band with the bottom foil (bottom shrink), so that the folio top sheet or the top of the folio top sheet is heated by the rising hot air. As a result of the lifting of the pressing plate, a heating space is thus generated above the stack of goods or above the folio cover sheet. The described heating of the foil cover sheet or the top side of the foil cover sheet preferably takes place with the proviso that there is no welding of the foil cover sheet with the folded-over projecting portions of the foil strip. Depending on this, the timing of lifting the squeeze plate during the process is selected. Preferably, the foliar cover sheet is then cooled to the extent that it hangs tightly and without welding over the folded-over protrusion portions of the film band. Then creates a flat surface on the stack, so that here water or similar liquid can not accumulate easily. in this respect This embodiment is characterized by a considerable advantage compared to the known methods described above.

The invention is based on the finding that with the method according to the invention the disadvantages described above can be effectively and reliably avoided. In particular, leaks can be effectively reduced in the region of the upper side of the stack of goods or between the folio cover sheet and the overhang sections of the film band. In this way it can be avoided that water passes from the side below the film to the stacked goods and there produces product damage, such as mold. Furthermore, disadvantageous trapped air can be avoided or substantially reduced by the method according to the invention. The method according to the invention can also be realized in a less expensive or less costly manner. The device for carrying out the method according to the invention is characterized by a simple or less complex construction.

Fig. 1

eine Seitenansicht einer Vorrichtung zur Durchführung des erfindungsgemäßen Verfahrens ,

Fig. 2

eine perspektivische Draufsicht auf den Gegenstand gemäß Fig. 1 und

Fig. 3

den Gegenstand nach Fig. 1 in einer zweiten Funktionsstellung.

The invention will be explained in more detail with reference to a drawing showing only one exemplary embodiment. In a schematic representation:

Fig. 1

a side view of an apparatus for carrying out the method according to the invention,

Fig. 2

a perspective top view of the article according to Fig. 1 and

Fig. 3

the object after Fig. 1 in a second functional position.

The figures show a device for shrinking a film 1 on a stack 2, wherein the stack 2 is preferred and in the embodiment cuboid with four sides, bottom and top 3 is formed. First, a shrink-wrap film band 4 is placed around the sides adjoining each other over the circumference of the stack 2. At the upper edges 5 of the stack 2, the film band 4 on protruding projecting portions 6, which are folded over on the top 3 of the stack 2 and are preferably fixed there. Subsequently, a Foliendeckblatt 7 is placed on the top 3 of the stack 2 and on the folded-over projections 6 of the film band 4. In this case, the Foliendeckblatt 7 projects with film sections 8 on the upper edges 5 of the stack 2. Preferably, and in the embodiment, the film band 4 is shrunk by means of a shrink frame or hot air shrink frame 9 on the stack 2 or on the sides of the stack 2. The hot-air shrink frame 9 may in the embodiment according to the figures have a plurality of distributed over its circumference and not shown heaters for heating the film band 4 for the shrinking process.

First, in the context of the inventive method, the hot-air shrink frame 9 is preferred and in the embodiment in a in the Fig. 1 shown center position moved vertically. In this case, a preferably tempered pressure plate 10 is pressed onto the top 3 of the stack 2 or on the folio cover sheet 7 resting thereon. Appropriately, and in the embodiment, the pressure plate 10 is heated or tempered to a temperature which is below the melting temperature of the plastic of the Foliendeckblattes 7. Empfohlenermaßen and in the embodiment, the press plate 10 is pressed with the proviso on the Foliendeckblatt 7, that Air from the folded-over projections sections 6 of the film band 4 or air between the supernatant sections 6 and the Foliendeckblatt 7 is pushed out laterally at the top of the stack 2. Preferably, and in the exemplary embodiment, a pressing plate 10 is used which projects with pressing plate sections 11 on all four sides of the stack 2 over the upper edges 5 of the stack 2. Conveniently and in the embodiment, the pressure plate forms 10 or the press plate 11 of the press plate 10, the ceiling of a shrink chamber 12. Empfohlenermaßen and in the embodiment, the shrink chamber 12 along the four sides of the stack 2 extending side walls 13. Preferably, and in the exemplary embodiment, these side walls 13 of vertically telescoping side wall sections 14, 15. Here border upper side wall sections 14 expediently and in the embodiment of the pressure plate 10 and preferred and in the embodiment, lower side wall portions 15 of the side walls 13 are connected to the hot air shrink frame 9 and moved with the hot air shrink frame 9. As a result, the shrinking chamber 12 can be variably adapted to different sizes of material stacks 2.

In the in the Fig. 1 shown hot air shrink frame 9 hot air is generated, which rises along the four sides of the stack 2. The position of the hot-air shrink frame 9 is adjusted so that with the rising hot air, the protruding film sections 8 of the Foliendeckblattes 7 are heated as well on the sides of the stack 2 adjacent upper band portions 16 of the film band 4, so that the film sections 8 on the sides of the stack 2 welded to the upper Banderolenabschnitten 16 or welded. It is within the scope of the invention that this welding over the entire circumference the goods stack 2 takes place. In this way, a very tight or watertight connection between film band 4 and Foliendeckblatt 7 results.

Preferably, and subsequently, and in the exemplary embodiment, the hot air shrink frame 9 is moved downwards on the stack 2. Appropriately, the hot air shrink frame 9 is thereby shut down so fast that air in the spaces between the film band 4 and stack 2 is pressed down or pushed out of the bottom of the film band. It can be seen in the figures that the stack 2 is preferably arranged on a pallet 17. In the in Fig. 3 shown lower position of the hot air shrink frame 9 is preferably carried out and in the embodiment, a welding between the film band 4 and a pallet between 17 and stack 2 arranged bottom sheet 19 (so-called under shrinkage). It is within the scope of the invention that the hot-air shrink frame 9 then moves up again for shrinking or further shrinking of the film band 4 on the sides of the stack 2. The shrinking of the film band 4 can also take place when shutting down the hot air shrink frame 9 on the stack 2. The shrinking of the film band 4 on the sides of the stack 2 is also referred to as side shrink.

Preferably, and in the exemplary embodiment, the pressing plate 10 pressed onto the upper side 3 of the stack of goods 2 is moved upward during the lower shrinkage ( Fig. 3 ). In this case, a heating chamber 18, into which the rising heated air can penetrate, is produced between the pressing plate 10 and the foil cover plate 7, which has been preheated by the pressing plate 10. As a result, the film cover sheet 7 is further heated. Expediently, the heating of the foil cover sheet 7 takes place with the proviso that no welding of the foil cover sheet 7 with the folded-over projections 6 of the foil band 4 takes place. During the subsequent cooling of the film cover sheet 7, this is tightened relatively tightly on the upper side 3 of the stack 2, so that an advantageous flat surface forms on which disadvantageous water deposits or puddles of water can not form.

The width b of the protrusion sections 6 of the film band 4 may preferably be 50 to 400 mm. The width B of the film sections 8 of the film cover sheet 7 may preferably be 100 to 300 mm.

Claims (11)

1. A method for applying a film (1) on a stack of goods (2), in particular for shrink-fitting a film (1) on a stack of goods (2), wherein the stack of goods (2) comprises at least one unit,
   wherein a film sleeve (4) is first placed around sides of the stack of goods (2), said sides lying adjacent to one another around the periphery of the stack of goods (2),
   wherein projecting portions (6) of the film sleeve (4) projecting above the upper edges (5) of the stack of goods (2) are folded over onto the upper side (3) of the stack of goods (2),
   wherein the film top sheet (7) is then placed onto the upper side (3) of the stack of goods (2), wherein the film top sheet (7) projects with film portions (8) beyond the upper edges (5) of the stack of goods (2),
   characterised in that a pressure plate (10) is then pressed on the upper side (3) of the stack of goods (2) or on the film top sheet (7) lying on said stack of goods,
   that hot air is then generated which ascends along the sides of the stack of goods and heats the projecting film portions (8) of the film top sheet (7) in such a way that the film portions (8) are welded to the film sleeve (4) lying adjacent to the sides of the stack of goods,
   wherein the film portions (8) initially hanging down at the upper edges (5) of the stack of goods (2) are lifted by means of the ascending hot air, fall back again onto the sides of the stack of goods (2) as a result of the heating thus occurring and weld there with the heated sleeve portions (16).
2. The method according to claim 1, wherein the pressure plate (10) is heated or temperature-regulated to a temperature which lies below the melting temperature of the material or of the plastic of the film top sheet (7).
3. The method according to any one of claims 1 or 2, characterised in that the pressure plate (10) is pressed on the film top sheet (7) in such a way that air is pushed out or pressed out from the folded-over projecting portions (6) of the film sleeve (4) and/or air between the projecting portions (6) and the film top sheet (7) and/or air between the projecting portions (6) and the upper side (3) of the stack of goods (2) is pushed out or pressed out.
4. The method according to any one of claims 1 to 3, characterised in that use is made of a pressure plate (10) which projects with pressure plate portions (11) beyond the upper edges (5) of the stack of goods (2) and preferably beyond the edges of the film top sheet (7).
5. The method according to any one of claims 1 to 4, characterised in that the pressure plate (10) forms a ceiling of a shrink chamber (12), wherein the shrink chamber (12) comprises side walls (14) extending along the sides or along the lateral surfaces of the stack of goods (2), and that the hot air is conveyed through the shrink chamber (12) in the direction of the upper side (3) of the stack of goods (2).
6. The method according to any one of claims 1 to 5, characterised in that at least upper sleeve portions (16) of the film sleeve (4) are heated by the ascending hot air, so that these upper sleeve portions (16) are welded to the heated film portions (8).
7. The method according to any one of claims 1 to 6, characterised in that the ascending hot air is generated with a hot-air shrinkage frame (9) surrounding the sides of the stack of goods (2), wherein the position of the hot-air shrinkage frame (9) is selected with the proviso that lifting of the film top sheet (7) and welding of the film portions (8) to the sleeve portions (16) takes place by means of the ascending hot air.
8. The method according to claim 7, characterised in that the film sleeve (4) is shrink-fitted on the stack of goods (2) with the hot-air shrinkage frame (9).
9. The method according to any one of claims 7 or 8, characterised in that, after the heating of the projecting film portions (8), the hot-air shrinkage frame (9) is traversed downwards along the sides of the stack of goods (2) and that a bottom film (19) of the stack of goods (2) is preferably welded to the film sleeve (4) with the aid of the hot-air shrinkage frame (9).
10. The method according to any one of claims 1 to 9, characterised in that the pressure plate (10) is raised during the shrink-fitting of the film sleeve (4) or during the welding of the film sleeve (4) to the bottom film (19), so that the film top sheet (7) or the upper side of the film top sheet (7) is heated by the ascending hot air.
11. The method according to claim 10, characterised in that the heating of the film top sheet (7) or the upper side of the film top sheet (7) takes place in such a way that welding of the film top sheet (7) to the folded-over projecting portions (6) of the film sleeve (4) does not take place.

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