EP0077805A1

EP0077805A1 - Package and apparatus for its manufacturing.

Info

Publication number: EP0077805A1
Application number: EP82901417A
Authority: EP
Inventors: Eberhard Kochanek
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-05-05
Filing date: 1982-05-04
Publication date: 1983-05-04
Also published as: EP0077805B1; WO1982003836A1; DE3117736C2; DE3265772D1; DE3117736A1

Abstract

L'emballage est obtenu en disposant un film plastique (8) sur un cadre en carton ondule (4) n'ayant que des parois verticales, en portant le film a une temperature superieure a la temperature de ramollissement, en l'appliquant sous pression et en l'aspirant dans une matrice (48) partiellement dans le cadre. Le film se soude partiellement au-dessus de la matrice a la paroi interieure du cadre, tandis que le reste du film se conforme a la matrice en se refroidissant. L'outil superieur (50) presente des poincons (68) au contact desquels le film se refroidit immediatement tout en conservant son epaisseur de paroi d'origine. Le cadre en carton ondule (4) peut comporter des evidements dans des bords superieurs et inferieurs pour pouvoir recevoir, sans solution de continuite, les emballages superposes lors de l'empilement croise.The packaging is obtained by placing a plastic film (8) on a corrugated cardboard frame (4) having only vertical walls, by bringing the film to a temperature above the softening temperature, by applying it under pressure. and sucking it in a matrix (48) partially in the frame. The film is partially welded above the matrix to the inner wall of the frame, while the rest of the film conforms to the matrix as it cools. The upper tool (50) has punches (68) in contact with which the film cools immediately while retaining its original wall thickness. The corrugated cardboard frame (4) may include recesses in upper and lower edges so as to be able to receive, without a solution of continuity, the packages superimposed during cross stacking.

Description

Packaging unit, process for its production and device for carrying out this process

The invention relates to a self-supporting, stackable packaging unit according to the preamble of claim 1, a method for its production and an apparatus for carrying out this method.

A packaging unit according to the generic term is known from DE-OS 28 19 869 in the form that the relevant frame, preferably made of corrugated cardboard, has inwardly flaps attached to its upstanding wall sections, and onto the essentially flat surface thus formed the film in question is skinned with its edge. After the flaps mentioned have been folded up again, the narrower wall sections of the frame can be folded inwards on the middle vertical creases, as a result of which the packaging unit itself is given an economically storable, flat shape. However, it is disadvantageous that a not inconsiderable amount of packing space is lost due to the flaps which surround the window and are folded inwards. Then the stored, folded packaging units, as soon as they have temporarily absorbed some moisture, tend to Use to spring back to the folded state, which makes handling very difficult.

The invention is therefore based on the object to form a self-supporting, possibly stackable packaging unit of the generic type in such an economical manner that the interior of the cardboard frame can be used as fully as possible, that the finished packaging unit can be folded easily and in a space-saving manner and that it can still be used does not tend to spring back to the folded state.

This object is achieved by the characterizing features of patent claim 1.

Due to the lack of inward-facing rags, almost the entire interior of the frame is available for packing purposes. The film pulled down on the inside finds at least as good a hold on the frame as this by means of the inwardly directed tabs according to FIG

DE-OS 28 19 869 is the case. In addition, the material of these rags is saved. The packaging unit according to the invention can simply be folded in parallelograms along its vertical frame edges, as a result of which ultimately only two wall thicknesses of the cardboard frame come to lie one on top of the other in the area of an adhesive flap compared to four or five wall thicknesses in the previously known packaging unit.

From DE-OS 27 21482 it is already known to have longer upstanding wall sections of the cardboard frame end bluntly with a relevant self-supporting, stackable packaging unit. On the narrow sides, however, cardboard sections directed inward again occur here and close to them the side walls in question are angled so that there are now four connection points for the frame instead of a single one. Once the packaging units in question are no longer foldable, they can only be completed by the userii. In addition, the film covers the entire cardboard blank, which also results in an unnecessary expenditure of material.

Furthermore, from DE-OS 22 00 710 a packaging unit is known which as a display pack within a cardboard frame having only upright wall sections, the outer edge of which extends over part of the frame height on the inner wall of the frame. However, these are self-supporting hard-film parts which are held in the frame in a form-fitting manner only by means of tabs of the frame which are inwardly pronounced, and are therefore not adherent.

Then, from DE-OSen 1 761 693 and 28 12 636 cups are known, which are obtained from a substantially frustoconical housing by the inner side of a film, the film reaching out over the upper rim of the cup. In the case of DE-OS 28 12 636, the film can also form the sole cup base. In the meantime, these cups, which are naturally not foldable and cannot be stacked after filling, always have an outward-facing roll collar, and the film is deep-drawn to the bottom of the cup.

Claims 2 to 5 contain advantageous developments of the packaging unit according to the invention, the one according to claim 5 also being characterized by particular dimensional stability when it is possible to accommodate a relatively large number of individual objects.

The inventive method according to claims 6 and 7 makes it possible to package units according to the invention to produce in a particularly reliable and economical manner. Proceeding from a manufacturing process according to DE-OS 28 19 869, in which, however, the film is peeled on from above by a heated plate, good and permanent adhesion of the film to the inner wall of the frame is now achieved with simple means.

The remaining claims are directed to a device for the economical and precise implementation of the method according to the invention, again from the DE-OS

28 19 869 is assumed. A device with partially Similar elements are also shown in the aforementioned DE-OS 23 12 636, but in contrast to claim 8 no lower tool acting on the film is used. Incidentally, the heating of the film in this fan is to be carried out by hot air initially blown into the closed device.

The claimed measures and their peculiarities are described in more detail below using examples with reference to the drawings. Of which shows

1 is a perspective view of a packaging unit according to the invention,

2 shows the cut of the relevant frame,

3 shows a section through the packaging unit according to FIG. 1,

4 shows a similar section through a packaging unit according to the invention in a modified embodiment which is suitable for receiving a plurality of individual objects lying next to one another,

5 shows a section through a device according to the invention for producing a packaging unit according to FIG. 4,

6 shows a side view of a stack of several similar packaging units according to the invention

7 is a side view of the same type of a stack of differently dimensioned packaging units according to the invention and

Fig. 8 shows a detail from the cardboard frame of another stackable packaging unit according to the invention.

The packaging unit 2 shown in FIGS. 1 and 3 essentially consists of a rectangular frame 4 made of corrugated cardboard and a film 8 covering the window opening 6 and skinned onto the frame.

The blank 10 of the frame 4 is shown in a developed form in FIG. 2. As can be seen from this, the frame has only two longitudinal, essentially rectangular wall sections 12 and 14 and two equally high narrow-sided rectangular wall sections 16 and 18, apart from an adhesive tab 20 which laterally adjoins the free end of the wall section 14, which is preferably, as in FIG Fig. 1 shown inside on the Wall section 16 comes to rest to close the frame. The grooved bending edges later forming the frame corners are designated by 22 in FIG. 2. In addition, in the region of the longitudinal wall sections 12 and 14, the frame 4 has cutouts 24 and 26 which are still opposite one another on the top and bottom for a purpose which is explained below with reference to FIG. 6. Aside from these minor cutouts, the blank can be made from a cardboard sheet or web without any waste. As can be seen more precisely from FIG. 3, the film 8 covers the top end face of the frame 4 and extends downwards from there on the inside of the frame, adhering approximately to the upper quarter of the upright wall sections 12 to 18 together with the adhesive tab 20. Below the connection point 28 formed in this way, the film extends obliquely inwards in order to form a trough 32 in the lower part of the frame with a floor 30 which is flat in this example and which receives the object 34 to be packaged, for example an assembly part. The oblique walls 36 of the trough 32 prevent the object 34 from bumping against the frame 4.

4 shows a somewhat modified embodiment of a packaging unit according to the invention, in which the frame 4 is essentially the same, but the film 8 has a plurality of troughs 32 ', which may be adjacent to one another in two coordinates, in order to accommodate a plurality of objects 34' within a frame. The individual troughs 32 'are separated from one another by webs 40 formed in the film, which are formed by inclined walls 42 similar to the inclined walls 36 in order to prevent the objects 34' from colliding with one another. However, in order to stiffen the entire arrangement of troughs 32 'and webs 40, ie on a possible one To prevent sagging, the walls 42 can be connected in places as shown in dashed lines in FIG. 4, for example by welding.

Fig. 5 shows a device 44 for producing a packaging unit according to Fig. 4. This device is preferably located at the end of a conveyor track for already finished cardboard frames 4, on which the relevant plastic film 8 is placed as a web and which then a e.g. tunnel oven equipped with electric radiant heaters. Such a conveyor track, on which the individual cardboard frames follow one another closely side by side, is only indicated in the figure as a table, 46.

The device itself has two tools that can be moved vertically relative to one another, namely a lower tool 48, each holding a frame 4, and an upper tool 50.

The lower tool 48 is designed according to the shape of the film 8 below the connection point 28 (FIGS. 3 and 4) and has a shoulder 52 on the outside on which the frame 4 comes to rest. More precisely, the shoulder 52 carries a sealing strip 54, for example made of silicone rubber, which is adapted to the shape of the lower frame edge 56, including the cutouts 24 and 26 there, in order to seal it as tightly as possible. Vent channels 58 open at the bottom of the two trough cavities 60, which form the troughs 32 'of the film

(Fig. 4) are determined. An intermediate rib 62 of the lower tool, which is used to form the webs 40 of the film, is, as shown in dashed lines in FIG. 5, recessed in places in order to accommodate the one in connection with FIG. 4 To allow described welding of the two web walls 42 in places. If necessary, the tool 48 can, as is also indicated by dashed lines, have further ventilation channels 64.

The upper tool 50 essentially consists of a first plate, 66, on the underside of which there is a number of mushroom-shaped projections 68 corresponding to the number of trough cavities 60, and of a second plate guided up and down on the shafts 70 of the projections 68, 72. The plate 66 has on the underside near the edge an elastic buffer strip 74 with which it can rest on the plate 72. The plate 72 in turn bears on its underside a sealing strip 76 similar to the sealing strip 54 of the lower tool, with which it is able to press the film 8 lying on the frame 4 tightly against the upper frame edge 78. Both strips can in turn be made of silicone rubber. Then the two plates 66 and 72 also have ventilation channels 80 and 82, of which the ventilation channels 82 of the plate 72 consist of a plurality of through-holes surrounding the shafts 70, which, seen in plan view, still open within the plates 84 of the projections 68.

The two tools 48 and 50 are not heated. As described above, they can even be chilled. Now use them as follows:

First, when the tools 48 and 50 have moved apart, the lower tool 48 receives a cardboard frame 4 together with the film 8 lying thereon and heated to its softening temperature. Then lower tool 48 and upper tool 50 are moved together, first under the influence of their own weight and possibly with the support of springs, not shown Plate 72 comes to rest on its sealing strip 76 on the film and thus on the upper edge 78 of the frame. In the further course, the film clamped in this way is stretched by the projections 68 now emerging downward from the plate 72, it already entering the hollow cavities 60. The parts of the film which come into contact with the projections 68 cool down immediately, as a result of which they essentially retain their original wall thickness. As can be seen, this is the case in the base region of the depressions 32 ', where the film will be most stressed in use by the objects 34' lying there.

Towards the end of the counter-movement of the tools 48 and 50, the plate 66 comes to rest on the plate 72 via its buffer strip 74, as shown in the figure, as a result of which the last one is additionally pressed against the upper edge 78 of the frame. Now a differential pressure is applied by means of the ventilation or ventilation channels 58, 64, 80 and 82, be it by suctioning off via channels 58 and 64, or by blowing air through channels 80 and 82 or both. In any case, this differential pressure has the consequence that the film lies above the lower tool in the area of the later connection point 28 on the inner wall of the cardboard frame 4 in order to weld to it, as well as to the upper frame edge 78 if necessary. Furthermore, due to the differential pressure, the already stretched film fits snugly against the lower tool without causing wrinkles or similar, sometimes observed disturbances. As soon as the lower tool is touched, the film section in question cools down, which permanently assumes the shape of the lower tool.

To separate the relevant film 8 from the supplied film web, the plate 66 can, as shown, be connected to an electrically heated wire 86, which towards the end of the downward stroke of the plate passes through the film web. When the tools 48 and 50 are moved apart again, the finished packaging unit as shown in FIG. 4 is obtained.

In order to prevent the film from sticking to the lower tool as well as to the projections 68 of the upper tool, the surfaces thereof that come into contact with the film can be coated with a conventional release agent, such as e.g. Tetrafluoroethylene.

As previously mentioned, the film is heated as it is fed to device 44. The tools 48 and 50 absorb the heat of the film as soon as they come into contact with it, as a result of which the film is solidified in its form. In order to make this possible in continuous production in the long term, the tools may have to be cooled. One possibility for cooling of this type is to equip the tools with cooling water channels which are connected to corresponding supply and discharge lines, if necessary via hoses. Then the tools can also carry cooling fins on the outside, which, if necessary via suitably arranged guide channels, are blasted with air via a blower. Such measures are common in technology, so that a more detailed description is unnecessary here.

FIG. 6 shows a stack-like arrangement of a plurality of packaging units according to the invention, which can continue, for example on a pallet, either upwards or to the sides. As can be seen, the packaging units 2 lying one above the other run for this purpose have a certain length / width ratio, crosswise to each other, their cutouts 24 and 26 interlocking with each other. This gives the stack a secure hold, even as long as it has not yet been secured by a shrink film or the like on the pallet or the like. This can be very useful for in-house transportation.

As can be seen from FIG. 7, in the case of a leaner format of the packaging units 2, they can also be stacked in such a way that they overlap one another in such a way that individual packaging units 2 '(but which are designed in the same way as the rest) meet the above and underlying packaging units come to rest. Of course, this has the consequence that the cutouts 24 and 26 of the packaging units in question must be arranged asymmetrically with respect to the vertical central axis of their longitudinal wall sections 12 and 14, so that when stacking it must be ensured that the packaging units are placed with a certain orientation.

FIG. 8 shows one possibility of circumventing this by continuously providing the upper and lower edges of the longitudinal wall sections 12 and 14 (only one of which is shown here in part) with sawtooth-like cutouts 88 in this example. Of course, others also come, such as rectangular, trapezoidal or rounded tooth shapes in question.

Another use of packaging units according to the invention is to place them on top of or against each other in pairs to form a shock-absorbing packaging, preferably in such a way that their cutouts 24, 26 and 88 interlock again. Then the frame can also be made of another flat Material as corrugated cardboard, for example a corresponding plastic product or possibly cardboard. After all, the film used does not have to be a skin film. In this case, the frame wall can be provided with an adhesive, preferably one, at the appropriate point

Hotmelt, are coated on which the film, for example a polypropylene film, adheres to the described or a similar treatment.

Claims

Claims:

1. Self-supporting, stackable and foldable industrial packaging unit (2), essentially consisting of a frame (4) surrounding a window opening (6) and having upright wall sections (12 - 18) made of flat material, such as e.g. Corrugated cardboard, and a plastic film (8) that spans the window opening and conforms to the shape of the objects (34, 34 ') to the interior of the frame, the edge of which adheres to the frame by means of skinning or the like, characterized in that the frame (4) except The upright (12-18) has no further wall sections and the film (8), deep-drawn on the inside of the frame over part of the height of the frame, adheres to the inner surface of the frame.

2. Packing unit according to claim 1, characterized in that the film (8) below its fastening point (28) on the inner surface of the frame is bent or bent to the inside.

3. Packaging unit according to one of the preceding claims with a substantially cuboid frame (4), characterized in that the upstanding wall sections (12 - 18) have cutouts (24, 26; 88) on their obex and / or lower edge, which have the edges Above or underneath are able to accommodate similarly stacked similar packaging units (2).

4. Packaging unit according to claim 3, characterized in that the cutouts (88) form a continuous set of teeth.

5. Packaging unit according to one of the preceding claims, characterized in that the film (8) in a manner known per se in two coordinates, possibly offset from one another, each having a plurality of hollows (32 ') separated from one another by hollow webs (40) and in that at least part of the webs is stiffened by connecting the two opposite web walls (42) together in places.

6. The method for producing the packaging unit according to claim 1, in which the cardboard frame (4) is first trimmed and then, with the aid of an upper tool (50) and an unheated lower tool (48) adapted to the trough shape, the film (8) is skinned on using a differential pressure and shaped, characterized in that the film (8) placed on the frame and heated above its softening temperature is pressed against the upper edge (78) of the frame (4) by means of the unheated upper tool (50) and then the differential pressure is applied to the two Tools (48, 50) is applied to such an extent that the still hot film is sucked into the lower tool as well as against the inner wall area of the frame (4) lying above it.

7. The method according to claim 6, characterized g e k e n n z e i c h n e t that the prepared cardboard frames (4) are fed in close succession that on the successive frames, the film (8) continuously as

Railway is placed that the frame together with the through a tunnel oven and that the film of the respective packaging unit (2) is separated from the rest of the film web when the upper die (50) falls or subsequently.

8. Apparatus for carrying out the method according to claim 6, with upper and lower tools (50, 48) which can be moved against one another, of which the upper tool (50) is a substantially flat plate (72) which can be pressed against the upper edge (78) of the cardboard frame (4) ) and the lower tool (48) has a shape that dips into the frame and is adapted to the desired trough shape of the film (8), characterized in that the lower tool (48) frames (4) up to the height of the fastening point (28) of the film on the inside of the frame (8) fills and has at least one ventilation channel (58, 64) and that the tools (48, 50) are unheated and may even be coolable.

9. The device according to claim 8, characterized g e k e n n z e i c h n e t that the upper and possibly also the lower tool (50, 48) in the region of its pressure on the frame (4) has a sealing elastic pad (76, 54).

10. The device according to claim 8 or 9, characterized in that the upper tool (46) has a desired number of troughs of the film (8) corresponding downward from the plate (72) extendable projections (68) with a shape that these projections allows the film to come into contact as far as the film should essentially retain its original wall thickness during the molding process.

11. The device according to claim 10, characterized in that the projections (68) are located on a separate plate (66) on which the plate (72) which can be pressed against the upper edge (78) of the cardboard frame (4) is suspended up and down, and that this last-mentioned plate (72) can be pressed against the upper edge (78) of the frame by the first-mentioned plate (66) when approaching its lower end position by means of an elastic member (74).

12. The device according to one of claims 8 to 11 for the produc- tion of the packaging unit according to claim 5, characterized in that the respective webs (40) forming ribs (62) of the lower tool (48) are recessed in places such that the two opposite web walls ( 42) of the film (8) are able to connect to one another under the action of the differential pressure applied to the tools (48, 50).