EP0000168A1 - Heat shrinkable package, and method and apparatus for making same - Google Patents

Abstract

Shrink-film packagings are usually designed in such a manner that the object to be packaged is completely surrounded by a tubular film. This necessitates a corresponding material requirement. In order to reduce the film requirement in packagings of this type, the latter does not extend over the full surface of the underside of the object to be packaged, but edge strips (27) of the film (24) are fastened, e.g. by sticking, on the underside (21) of the object (22) in the edge region of the same. As a result, the character of a usual shrink-film packaging is maintained externally. The material requirement is, however, reduced. <IMAGE>

Description

The invention relates to packaging with a tray to be packed and a partially wrapping shrink film. Furthermore, the invention relates to a method and device for producing such packaging.

Tray packs are widely used as relatively simple, low-material packaging for individual items such as cans, bottles, etc. The trays can only be made from a sheet of corrugated cardboard, cardboard or the like pick up the objects or from a floor with an erected board surrounding the objects. It is also known to wrap such tray packs in a shrink film. Finally, it has also already been proposed not to completely enclose tray packs provided with a shelf by means of a shrink film, but rather only to provide a shrink hood which is attached with an edge region on the outside to opposite side walls of the tray (shelf) by adhesive bonding. The majority of the shelf and the entire bottom surface of the tray remain free of shrink wrap. The latter type of pack is characterized by a lower film requirement, but has other disadvantages. In particular, it is undesirable for free edge flaps of the film to be formed in the region of the visible side surfaces of the pack, since this is not connected to the side walls of the tray over the entire area. This makes the package unsightly overall. It is also difficult to apply advertising and informational prints in the area of the side surfaces of the tray if the film is to be attached there by gluing.

Proceeding from this, the object of the invention is to propose a shrink film packaging equipped with a tray, in which the need for film material is reduced while maintaining the properties of a conventional shrink film packaging.

To solve this problem, the packaging according to the invention is characterized in that the Shrink film only extends to the edge areas of the underside of the tray and is fixed here, in particular by gluing, welding or the like.

In the case of the present packaging, it is therefore not the entire tray that is enclosed by the shrink film, but rather only its rim - if present - and an edge area on the underside. The majority of the tray floor remains free of shrink film, so that a corresponding amount of film is saved. From the outside, however, the character of a fully enclosed shrink film packaging is retained. In particular, the side walls (shelf) of the tray are also covered by film. Furthermore, the packaging can be designed so that the tray consists only of a base plate, on the underside of which the shrink film is attached in the edge region.

The above packaging can be produced by a method with successive process steps and a device suitable for this, or by a continuous packaging method with a corresponding device.

In the intermittently operating device, the shrink film is formed from two partial films, each of which is drawn off from separate film webs and placed around them with the objects to be packaged being lowered. The partial films are connected to one another at the top of the packaging, in particular by a fin seam.

In the continuously operating device, a continuously fed film web is placed around the likewise continuously conveyed, loaded trays in such a way that the film web lies with an edge strip on the underside of the trays in the edge region thereof and can be fastened here. Then the C-shaped foil sheet is cut in the area between the successive packs.

Further features of both the manufacturing process and the devices are the subject of the dependent claims.

• Figur 1 eine Verpackung mit Schrumpffolie im Querschnitt,
• Figur 2 eine intermittierend arbeitende Vorrichtung in schematischer Seitenansicht, in Ausgangsstellung,
• Figur 3 die Vorrichtung gemäß Figur 2 in einer ersten Zwischenstellung (Fertigstellung des Trays),
• Figur 4 die Vorrichtung gemäß Figur 2 und 3 bei unterer Stellung des Trays mit den zu verpackenden Gegenständen,
• Figur 5 die Vorrichtung gemäß Figur 2 bis 4 während der Endphase bei der Fertigstellung der Verpackung,
• Figur 6 die Vorrichtung gemäß Figur 2 bis 5.nach Fertigstellung einer Verpackung bei in die Ausgangsstellung zurückkehrenden Vorrichtungsteilen,
• Figur 7 einen Teil der Vorrichtung gemäß Figur 2 bis 6 im Grundriß, bei vergrößertem Maßstab,
• Figur 8 eine kontinuierlich arbeitende Vorrichtung für die Herstellung von Verpackungen gemäß Figur 1 in vereinfachter Seitenansicht,
• Figur 9 einen Grundriß zu der Vorrichtung gemäß Figur 8,
• Figur 1o einen Querschnitt durch die Vorrichtung gemäß Figur 8 und 9 in der Ebene X-X in Figur 8, bei vergrößertem Maßstab,
• Figur 11 eine Einzelheit über die Abteilung der einzelnen Verpackung als Alternative zu dem Ausführungsbeispiel gemäß Figur 8 und 9 in Seitenansicht, bei vergrößertem Maßstab,
• Figur 12 das Detail gemäß Figur 11 in Queransicht.

An exemplary embodiment of the packaging according to the invention and exemplary embodiments of the device for producing the same are explained in more detail below with reference to the drawings. It shows:

• FIG. 1 shows a packaging with shrink film in cross section,
• FIG. 2 shows an intermittently operating device in a schematic side view, in the starting position,
• 3 shows the device according to FIG. 2 in a first intermediate position (completion of the tray),
• FIG. 4 shows the device according to FIGS. 2 and 3 when the tray with the objects to be packed is in the lower position,
• 5 shows the device according to FIGS. 2 to 4 during the final phase when the packaging is finished,
• 6 shows the device according to FIGS. 2 to 5 after the completion of a package with the front returning to the starting position directional parts,
• 7 shows a part of the device according to FIGS. 2 to 6 in plan view, on an enlarged scale,
• 8 shows a continuously operating device for the production of packaging according to FIG. 1 in a simplified side view, FIG.
• FIG. 9 shows a plan view of the device according to FIG. 8,
• 1o shows a cross section through the device according to FIGS. 8 and 9 in the plane XX in FIG. 8, on an enlarged scale,
• FIG. 11 shows a detail of the department of the individual packaging as an alternative to the exemplary embodiment according to FIGS. 8 and 9 in a side view, on an enlarged scale,
• Figure 12 shows the detail of Figure 11 in a transverse view.

The packaging shown by way of example in FIG. 1 is suitable and intended for individual objects or for groups of objects ₂₀ , for example bottles, cans, etc. The objects 2o stand on a bottom wall 21 of a tray 22. In the present case, this tray 22 is provided with an upright rim 23 running all around. Alternatively, the tray 22 can also consist only of the bottom wall 21.

Tray 22 and objects 2o are partially enclosed by a film 24, in particular shrink film. The film 24 extends with an upper wall 25 from the top of the objects 2o over sides walls 26 to the underside of the bottom wall 21 of the tray 22.

only the underside of the bottom wall 21 is / to a lesser extent covered by the film 24, namely in the edge region by an edge strip 27 of the film 24. This edge strip 27 is connected to the underside of the bottom wall 21, for example by gluing, thermal welding or the like. The dimensions of the edge strip 27 and the area of adhesion to the bottom wall 21 are chosen such that a free edge tab 28 remains without connection to the bottom wall 21.

The foil 24 consists of two partial films 29 and 3 ₀ which are in the region of the upper wall 25 by thermal welding, here by a fin seam 31, connected to each other.

A device for producing the packaging according to FIG. 1 is shown in simplified form in FIGS. 2 to 7.

The device, which operates in cycles, contains a packaging platform 32. This is used to hold the parts of the packaging and can be moved in height to carry out the packaging steps, namely from a starting position according to FIG. 2 into a lower end position according to FIGS. 4 and 5 and back to the starting position according to FIG. 2.

The packaging platform 32 consists of a platform 33 and a film holder 34. Platform 33 and film holder 34 are arranged on a common carrier, namely a common lifting rod 35. At the upper, free end of this lifting rod 35, the platform 33 is. Includes the contents of the pack and the tray 22 brought. Below this platform 33, the film holder 34 is mounted on the lifting rod 35 with a guide 36 so as to be relatively movable.

The film holder 34 is provided with lateral, strip-shaped jaws 37 and 38, which extend outside the region of the platform 33, for receiving the edge strip 27 of the film 24 or the partial film 29 and 30. The top of the jaws 37 and 38 is designed to press the edge strips 27 onto the underside of the tray 22 and is equipped with heating strips 39 and cooling lines 40. Furthermore, a series of pointed retaining pins 41 are attached to the top of the jaws 37 and 38. In the initial position, the platform 33 and the film holder 34 are offset in height from one another, the relative position being fixed by a stop 42 on the lifting rod 35. This creates two levels. In the upper level at the level of the platform 33, the still unfolded blank for the tray 22 and the objects 20 are conveyed onto the platform 33. In the level below, the two partial foils 29 and 30 are conveyed in, as part of a foil web. The feed by pairs of pull rollers 43 and 44 is carried out in such a way that the edge strip 27 of the partial film 29 and 30 'lies in an exact relative position on the jaws 37 and 38 or on the holding pins 41. The conveyor track for the partial film 29 and 3o is each equipped with an upper guide 45 and an underpass 46. The former extends into the area of the upper packaging level. The upper guide 45 is also characterized by a beveled entry surface 47 as a mouthpiece opening for carrying out a folding step educated. The distances between the side surfaces of the opposing upper guides 45 are selected so that the remaining mouthpiece opening corresponds approximately to the dimensions of the tray 22.

The movement sequences during the manufacture of the packaging can be seen from FIGS. 2 to 6.

In the starting position according to FIG. 2, the inside of the shelf 23 is provided with an adhesive while the blank is still flat for the tray 22 by spray nozzles 48. By lowering the platform 33, the parts of the board 23 are erected and connected to one another as a result of the design and arrangement of the upper guides 45. In order to avoid relative displacements on the platform 33, a stamp-shaped counter-holder 49 with a lowerable, resting on the top of the objects 20 is provided.

When the platform 33 reaches the second level at the level of the partial foils 29 and 30, the tray 22 is completed by raising the shelf 23. The platform 33 is retracted between the jaws 37 and 38 by relative movement to the film holder, 34. As a result, the side regions of the tray 22 lower onto the jaws 37, 38. The holding pins 41 penetrate the film 24 and enter the bottom wall 21 of the tray 22. The edge strips 27 are in contact with the underside of the bottom wall 21. The edge strips 27 are connected here to the bottom wall 21 by heat and pressure.

Since the aforementioned connection cannot be subjected to high loads, the film 24 experiences in the area of the Edge strips 27 an additional momentary holder during the further packaging steps. This is on the one hand by the holding pins 41. In addition, however, the edge tab 28 not connected to the tray 22 is fixed by clamping. For this purpose, platform 33 and film holder 34 form clamping surfaces 50 and 51, which in the present case are directed obliquely. By appropriate insertion of the platform 33 between the jaws 37 and 38 of the film holder 34, the edge flaps are clamped 28 during the downward movement of the platform 33 between the clamping surfaces 5 ₀ 51 and held thereby.

In the further course, the entire packaging stage 32 with the tray 22 and the objects 20 is now lowered into the position according to FIG. 4. The partial foils 29 and 30 fixed with the edge strips 27 are taken away by pulling them off the foil web. In the lower position according to FIG. 4, the top of the objects 2o lies below the path of movement of transversely movable separating welding jaws 52 and 53. These now grasp the partial foils 29 and 3o and move them around the top of the objects 2o by movement towards one another. After this first phase of movement of the separating welding jaws 52 and 53, the counterholder 49, which is correspondingly smaller in plan, is moved back into the starting position. Now the further movement of the separating welding jaws 52 and 53 can take place along the upper side of the objects 2o with the entrainment of the partial foils 29 and 3o. Approximately in the middle of the packaging, the partial films 29 and 30 are connected to one another to form the fin seam 31 and at the same time separated from the subsequent part of the film web.

The packaging is now complete. For the lateral removal thereof, the film holder 34 is first slightly lowered again in the lower position of the packaging platform 32 (dash-dotted position in FIG. 5). This releases the retaining pins 41 from the tray 22 and the packaging can be removed from the side.

While the packaging platform 32 now returns to the starting position according to FIG. 2, the separating welding jaws 52 and 53 are also withdrawn to the starting position. In addition, the film webs or the partial films 29 and 30 for the next packaging are pulled back into a starting position according to FIGS. 2 and 3 by counter-driving the pulling roller pairs 43 and 44. In the meantime, a blank for a tray 22 has been fed into the upper level. This still flat blank lies on the top guide 45 of the conveyor track for the partial films 29 and 30.

The device according to FIGS. 8 to 12 is also used to produce a packaging with the essential features of FIG. 1. However, there is no top seam 31 on the top.

The tray 22 with objects 2o, which is to be partially encased here by a film 54, has already been completed elsewhere. On an endless conveyor 55, these loaded trays 22 are fed at a certain fixed distance from one another. In the present case, carriers 56 and 57 are arranged on both sides of the tray 22 on the top of the endless conveyor 55 for this purpose.

A film web 58 is continuously conveyed to the tray 22 conveyed on the endless conveyor 55 by a pair of draw rollers 59. The film web 58 is applied to the top of the objects 20 by the lower pull roller. During the further conveyance, the laterally projecting parts of the film web 58 are partially wrapped around the objects 20 or the trays 22 to form the top wall 25 and side walls 26. This wrapping process is carried out with the aid of known, stationary lateral folding switches 6o.

Following this folding switches 6o, the edge strip 27, which initially protrudes downward, is continuously applied to the underside of the trays 22. For this purpose, the endless conveyor 55 is dimensioned in the width so that the edge areas of the bottom wall 21 of the tray 22 remain free for the contact of the edge strips 27.

A running sweatband 61 beneath the trays 22 and with the upper run next to the endless conveyor 55 running in the middle is used to apply the edge strips 27 to the trays 22. The sweatband 61, for example made of Teflon, has one, as can be seen in FIG angular cross section with an erected edge 62. This places the edge strip 27 on the underside of the tray 22.

Fixed welding jaws 63 are mounted in the area of the sweatband 61. These press the traveling sweatband 61 against the underside of the packaging and at the same time transfer the heat required for connecting the edge strips 27 to the tray 22. Cooling jaws 64 connect to these welding jaws 63 in the further course of movement, which cool the connection produced for a short time and thereby make it durable.

The film tube, which now partially envelops the successive packagings, must be severed to form the individual packagings in the area between the trays 22. Two alternatives are provided for this.

8 and 9, the film web 58 is provided with a perforation 65 in the region of the pair of drawing rollers 59. This is designed in such a way that only slight residual webs which still ensure the cohesion of the film web 58 remain. A residual web 66 is located at the edge of the film web 58.

After the trays 22 have been wrapped, they leave the endless conveyor 55 with the highly coherent film web. The trays 22 arrive at a subsequent acceleration conveyor 68, which also has drivers 67. This is driven at a higher speed than the subsequent trays 22 with the film web. As a result of the difference in movement the film web is torn apart in the area of the perforation 65.

Trendrähten 7o ausgerüstet ist. Mehrere, im vorliegenden Falle drei Trenndrähte 7o sind jeweils an sternförmig angeordneten Tragarmen 71 quer zur Förderbahn der Trays 22 gerichtet angeordnet. Die Tragarme 71 werden gemeinsam rotierend angetrieben. Die Bewegung der Trenndrähte 7o ist auf die lineare Bewegung der Trays 22 und damit der Folienbahn 58 derart abgestimmt, daß jeweils ein Trenndraht 7o in den Bereich zwischen aufeinanderfolgenden Trays 22 in die umhüllende Folienbahn 58 eintritt und unter Durchführung der Trennung bei gleichzeitiger Abwärtsbewegung mitläuft. Die Trenndrähte 7o erreichen dabei jeweils im Bereich zwischen aufeinanderfolgenden Förderern die untere Stellung, in der die Folienbahn 58 vollständig durchtrennt ist. Die Trenndrähte 7o wandern dann bei weiterer Bewegung durch den gebildeten Spalt in der Folienbahn 58 wieder hindurch.In the embodiment according to FIGS. 11 and 12, a separating device 69 is arranged above the endless conveyor 55 and is equipped with separating tools in the form of

Trend wires 7o is equipped. Several, in In the present case, three separating wires 7o are each arranged on support arms 71 arranged in a star shape and directed transversely to the conveyor path of the trays 22. The support arms 71 are driven together to rotate. The movement of the separating wires 7o is coordinated with the linear movement of the trays 22 and thus the film web 58 such that a separating wire 7o enters the enveloping film web 58 in the area between successive trays 22 and runs along with the separation with simultaneous downward movement. The separating wires 7o each reach the lower position in the area between successive conveyors, in which the film web 58 is completely severed. The separating wires 7o then migrate through the gap formed in the film web 58 again upon further movement.

In order to achieve a wrinkle-free, smooth covering, lateral smoothing tools are arranged in the device, namely a number of obliquely directed smoothing brushes 72. These are driven at a greater peripheral speed than the movement of the trays 22, but in the direction of the same. As a result, the side walls 26 of the film web 58 are drawn smooth and at the same time the upper wall 25 is tightened. The upper wall 25 is also held by an upper band 73, which approaches the film web 58 immediately after the film web 58 has been applied to the objects 20.

Claims (20)

1. Packaging with a tray to be packed and a partially enveloping film (shrink film), characterized in that the film (24, 54) (shrink film) extends only to the edge areas of the underside of the tray (22) and is fixed here is, in particular by gluing, welding or the like. 2. Packaging according to claim 1, characterized in that the film (24, 54) consisting of two partial films (29, 3 ₀ ) is composed in the region of an upper wall (25) by a fin seam (31). 3. A method for producing a packaging with a tray holding the items to be packed and a sheet (24, 54) (shrink film) enveloping the items and the tray up to the edge region of the underside of the tray, characterized in that the sheet (24, 54) is temporarily fixed to the tray (22) at least during a phase of the production of the packaging and fastening to the tray (22) by additional (mechanical) holding means, in particular holding pins (41) penetrating through the film (24, 54) and entering the tray (22) ). 4. The method according to claim 3, characterized in that partial films (29, 3 ₀ ) separated from a separate web, placed around a portion of the package and connected to each other at the top. 5. The method according to claim 4, characterized in that the partial foils (29, 3 ₀ ) while holding the edge strips (27) to be connected to the tray (22) in the downward direction Movement of the tray (22) with the package contents placed around it and connected to one another approximately at the level of the supplied film webs. 6. The method according to any one of claims 3 to 5, characterized in that a free, not with the tray (22) to be connected edge tab (28) of the film (24) is held during the manufacture of the pack, in particular between jaws (5o, 51) is pinched. 7. The method according to any one of claims 3 to 6, characterized in that the tray (22) formed with a side up: right shelf (23) during the downward movement of the package contents with the tray (22) by erecting the shelf (23) is formed before the film (24) is placed around the tray (22) and the contents of the pack in the area of a lower level. 8. The method according to any one of claims 3 to 7, characterized in that after the completion of the film wrapping and separation from the subsequent film webs, these are moved back in the opposite direction to a starting position, such that the downward movement of a tray (22) subsequently produced edge strips (27) of the partial films (29, 3 ₀₎ are held in the required relative position with respect to the tray (22). 9. A method for producing packaging with a tray (22) receiving the items to be packed and a sheet (24) enveloping the items (2o) and the tray (22) up to the edge region of the underside of the tray (22), characterized that a continuous film web (58) from above during transport to units spaced apart from one another from a tray (22) and those to be packaged Objects (2o) are placed around the edge of the bottom of the tray (22) until an edge strip (27) abuts and is connected to it. 1 ₀ . Method according to claim 9, characterized in that after the edge strip (27) of the continuous film web (58) has been connected to the edge-side underside of the tray (22), the thus formed, cross-sectionally C-shaped film strand is severed in the area between the packages, in particular by tearing apart in the area of a perforation (65). 11. The method according to claim 9 or 1o, characterized in that the edge strips (27) of the continuous film web (58) are connected to the underside of the tray (22) during further transport by stationary or circumferential welding or adhesive tools (63) become. 12. The method according to any one of claims 9 to 11, characterized in that the foil web (58) which is placed around the filled trays (22) from above in the region of the side walls (26) by tightening in the direction of movement, in particular by rotating at a higher speed , inclined smoothing brushes (72) is smoothed out. 13. Device for producing packagings with a tray (22) to be packed (2o) and a partially enveloping shrink film, which is attached with an edge strip (27) to an edge area of the underside of the tray (22), characterized by a the tray (22) with the objects to be packaged (2o) receiving, upwardly and downwardly movable packing stage (32), fixed on the underneath of the tray (22) edge regions of two opposite sides of feedable part slides (29, 3 ₀₎ 14. The apparatus according to claim 13, characterized in that the packaging platform (32) consists of a platform (33) for receiving the tray (22) and a film holder (34) for the edge regions of the partial films (29, 3 ₀ ), the Platform (33) for receiving the tray (22) is arranged above the film holder (34) in the starting position, such that trays (22) with objects to be packaged (20) in an upper level and the partial films (29 , 3 ₀ ) can be fed. 15. The apparatus according to claim 14, characterized in that after receiving a tray (22) through the platform (33) and receiving the edge strips (27) of the partial films (28, 3 ₀ ) by the film holder (34) the former to the level of the film holder (34) can be lowered and then the platform (33) and film holder (34) can be lowered together while taking the partial films (29, 3 ₀ ) in such a way that transversely displaceable separating welding jaws (52, 53) above the objects (2o) to be packaged taking along the partial films (29, 3 ₀₎ to the connection and disconnection thereof are moved toward each other from the side. 16. The apparatus according to claim 14 or 15, characterized in that the film holder (34) formed with lateral, strip-shaped jaws (37, 38) on the upper side holding means, in particular a series of pointed holding pins (41), for fixing the edge strip (27 ) of the partial sheets (29, 3 ₀₎ at the bottom of the tray (22). 17. Device for producing packagings with a tray (22) receiving the objects to be packaged (2o) and a film (24) (shrink film) partially enveloping them, which consist of the continuously conveyed trays (22) is formed with the objects to be packaged (2o) and can be wrapped around this C-shaped film web, characterized in that the finished trays (22) with the objects (2o) to be packaged on an endless conveyor (55) with defined, by carriers ( 56, 57) or the like. Specifically defined distances can be fed from one another and the film web (58), which is dimensioned accordingly in width, by stationary folding switches (6 ₀ ) during transport until an edge strip (27) bears against the underside of the trays (22) this is foldable. 18. The apparatus according to claim 17, characterized by an upper belt (73) consisting of an upper guide (45) through which the film web (58) on the top of the objects to be packaged (2o) is fixed during a conveyor line. 19. The apparatus according to claim 17, characterized in that at the endless conveyor (55) is connected to an acceleration conveyor (68), which with higher. Speed is driven as the endless conveyor. (55). 2 ₀ . Apparatus according to claim 17, characterized in that several, in particular three, separating wires (70) are arranged on a circumferential carrier with support arms (71) in such a way that, with a coordinated relative speed, the heated separating wires (7o) during the further movement of the film web (58) into it are able to penetrate by severing them ..

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