EP0456011B1 - Device for making a box of cardboard provided with a layer of thermoplastic material - Google Patents

Description

The invention relates to a device for producing a can from plastic-coated cardboard according to the preamble of claim 1 (see GB-A-704608).

In DE-A-30 23 835 a can is shown and described, which consists of a plastic-coated cardboard with an embedded aluminum layer and - in the finished state - contains a sleeve, on the two open end faces of which an end wall is attached. The known devices for producing such cans are designed so that they first produce this can in the form of a cup open on one side, into which the contents are filled. The manufacturing device therefore provides only one station for inserting an end wall. After filling, the second end wall is then used on another device, a type of induction welding being used there, just as when inserting the first end wall, to seal the seams against one another, which also requires the use of an aluminum layer. If filled cans are produced in this way, the introduction of the second end wall, which can also have a hole closed with a tear-off tab, which later serves as an emptying opening, for example for inserting a straw, is made more difficult. The contents already in the can impair the attachment of the second one Front wall, for example, in that moisture gets into the area of the sealed seams.

The invention is therefore based on the object of designing a device of the type mentioned at the outset in such a way that these disadvantages are avoided. In particular, it should be possible in a simple manner to provide flawless sealing seams for both end walls, and it should be prevented that, in the case of liquid contents, moisture can penetrate into the seam area before sealing.

This object is achieved in a device of the type mentioned by the characterizing features of claim 1. The new device therefore makes it possible to attach both end walls before the can is filled. The seams can therefore be sealed with simple means and perfectly, whereby it is sufficient, as in other similar manufacturing processes, for example to use hot air to seal the seams. There is no danger of moisture penetrating into the seam area, so that the prescribed sealing temperatures can be easily achieved. Since one of the end walls used has a filling opening, the can can be filled afterwards, it being no problem to subsequently close the relatively small filling opening properly. It is advantageous that the sleeve to be provided with the second end wall can be guided in a holder engaging on the circumference of the sleeve, so that the can can be handled properly and safely in its empty state up to its final shape.

A mandrel can be provided in a simple manner for winding the sleeve and for inserting the first end wall, as is expressed in claim 2. According to the features of claim 3, this mandrel can be part of a star wheel which can be rotated in cycles from a winding station for the sleeve to a station for inserting the first end wall. This Star wheel can then be assigned a second star wheel according to claim 9, which includes the holder on which the can is completed with the filling opening still open.

It is advantageous if the station for inserting the first end wall is assigned a conveyor for a cardboard tape, which is already provided with the prefabricated filling openings at such a distance from one another in a simple manner that it is sufficient according to the features of claim 4, the station for Insert the first end wall to assign a cutting device with which only round blanks are punched out of the cardboard band, which are then provided with a frame in accordance with the features of claim 6 in a station for bending the edge of the end walls. It can be particularly advantageous if, according to the features of claim 6, this cutting station is followed by an insertion station for a filler neck, which in particular can be provided with a screw thread and therefore - after removing a screw cap - not only as a filling opening but also as an emptying opening can serve.

Fig. 1

einen Längsschnitt durch eine mit einer erfindungsgemäßen Vorrichtung hergestellte, noch unbefüllte Dose mit einer noch unverschlossenen Aufreißlasche,

Fig. 2

einen Längsschnitt durch eine andere nach der Erfindung hergestellte Dose mit einem Einfüllstutzen,

Fig. 3

den Zuschnitt eines Mantels für die zu wickelnde Hülse,

Fig. 4

die Hülse vor dem Einsetzen der Stirnwände,

Fig. 5

ein Kartonband mit bereits vorbereiteten Füllöffnungen, aus dem die ersten Stirnwände in der erfindungsgemäßen Vorrichtung angeschnitten werden,

Fig. 6

eine aus dem Kartonband ausgestanzte Ronde für die erste Stirnwand,

Fig. 7

einen Längsschnitt durch eine bereits mit einer Zarge versehene erste Stirnwand,

Fig. 8

einen Teil einer erfindungsgemäßen Vorrichtung mit einem ersten Sternrad zum Herstellen eines aus Hülse und erster Stirnwand bestehenden Bechers und

Fig. 9

den zweiten Teil der Vorrichtung nach Fig. 8 mit einem zweiten Sternrad zum Fertigstellen der Dose.

Further advantages and features of the invention result from the following description of some exemplary embodiments, which are shown in the drawing. Show it:

Fig. 1

2 shows a longitudinal section through a still unfilled can produced with a device according to the invention with a tear tab which is still unlocked,

Fig. 2

2 shows a longitudinal section through another can produced according to the invention with a filler neck,

Fig. 3

cutting a jacket for the sleeve to be wound,

Fig. 4

the sleeve before inserting the end walls,

Fig. 5

a cardboard tape with already prepared filling openings, from which the first end walls are cut in the device according to the invention,

Fig. 6

a blank punched out of the cardboard tape for the first end wall,

Fig. 7

a longitudinal section through a first end wall already provided with a frame,

Fig. 8

a part of a device according to the invention with a first star wheel for producing a cup consisting of sleeve and first end wall and

Fig. 9

the second part of the device of FIG. 8 with a second star wheel for finishing the can.

1 shows a first exemplary embodiment of a can (1) produced according to the invention. It contains a wound sleeve (2) into which end walls (3, 4) are inserted. The sleeve (2) and the end walls (3, 4) each consist of plastic-coated cardboard, optionally without an embedded aluminum layer.

The end wall (3) forming a bottom is provided with a frame (5) around which the end region (6) of the sleeve (2) is rolled. This creates a seam area (7) which is sealed tight after heat sealing. The device for production shown in FIGS. 8 and 9 therefore has corresponding hot air nozzles.

Correspondingly, the end wall (4) forming a lid has a frame (8) around which the end region (9) of the sleeve (2) is also rolled. A seam region (10) is thus also formed on the end wall (4) and is sealed tight after heat sealing.

The end walls (3, 4) are inserted into the sleeve (2) before the can (1) is filled with a filling material, for example a drink. For this reason, the end wall (4) has a filling opening (11) which can be identical to the later emptying opening. The cut edges (12) of the filling opening (11) are sealed with a cut edge protection. Cut edge protection can be ensured, for example, by coating the cardboard, which protrudes like a film over the cut edges (12).

The end wall (4) can already be provided with a closure element (13) before insertion, which merges into a tear-open tab (14) which is still open. After the can (1) has been filled, the tear-open tab (14) can be closed in a simple manner. Alternatively, a pull tab can be attached after the can (1) has been completed, but before it is filled, but the pull tab is still open.

Because the end walls (3, 4) are inserted into the sleeve (2) before the can (1) is filled, the seam areas (7, 10) can be sealed tightly. A possibly liquid filling material has no opportunity to impair the seam areas (7, 10) and to make the sealing process more difficult.

The box (15) according to FIG. 2 represents another embodiment according to the invention and differs from the box (1) of FIG. 1 essentially in that another end wall (16) is used in the box (15). Even before insertion into the sleeve (2), a filler neck (17) was attached to the end wall (16), which later also serves to empty the can (15). The filler neck (17) suitably consists of plastic and is sealed to the web of the end wall (16) with a flange (18). A sleeve-like area (19) of the filler neck (17) containing the filling opening (11) has an external thread (20) so that the filled can (15) can later be closed with a screw cap.

With this configuration, too, it is possible in a simple manner to seal the seam regions (7, 10) in a sealed manner by heat sealing before filling the can (15).

Fig. 3 shows the tailored jacket (21) from which the sleeve (2) is wound. The jacket blank (21) is an essentially rectangular blank, the opposite edges (22, 23) of which form the later seam region (26) after the sleeve (2) has been wound (see also FIG. 4) and the other opposite edges (24 , 25) are located on the end faces of the sleeve (2).

In Fig. 4 you can see the already wound sleeve (2), in which the edges (22, 23) overlap in a seam region (26). The seam area (26) is sealed before the end walls (3, 4) are inserted.

5 shows the cardboard tape (27) to be transported in the direction of the arrow (A), from which the individual end walls (4) are produced, which are inserted first into the sleeve (2). The cardboard tape (27) is already prepared with the filling openings (11), so that the filling openings (11) do not have to be punched out first on the device for producing a can (1) or (15). It may be provided that the cut edges (12) are already suitably provided with cut edge protection. Of course, a device for punching out the filling openings (11) can also be integrated into the device according to the invention, which is shown in FIGS. 8 and 9.

FIG. 6 shows a circular blank (28) punched out of the supplied cardboard tape (27) for producing the end wall (4) (see FIG. 7). The circular blank (28) contains the already punched-out filling opening (11), which can optionally be provided with a cut edge protection, unless the version with the filler neck (17) is used, which then itself has the cut edge protection forms. The end wall (4) according to FIG. 7 already has the drawn frame (8).

8 and 9 show a device for producing cans (1 and 15), FIG. 8 showing one part (29) and FIG. 9 the second part associated with the first part (29) ( 49) of the device.

8 contains a so-called star wheel (30) which can be switched intermittently in the direction of the arrow (C). The star wheel (30), which can be rotated in time, contains a total of eight mandrels (31) which pass through processing stations (32 to 39) in succession.

The sub-device (29) contains a roll (40) which, in the direction of the arrow (B), delivers a cardboard tape (41), shown in dash-dot lines, for the jacket blanks (21). After the respective jacket blank (21) has been punched out, the later longitudinal seam region (26) is heated with hot air in a subsequent device (42), so that a subsequent apparatus (43) can apply a sealing strip for sealing the later inner cutting edge (22). The subsequent seam area (26) is folded over and pre-bent in a preliminary station (44) and heated again with hot air in a further station (45). A sheath (46) is then obtained, the areas of the cut edges (22, 23) of which are sufficiently heated that the sheath (46) can be wrapped around the mandrel (31) in the station (32), the seam area (26 ) is sealed so that a longitudinal sealing seam of the sleeve (2) is formed.

A cardboard tape (27) is fed from a roll (47) to the next processing station (33) in the direction of the arrow (A). This cardboard tape (27) can be prepared as it was already described with reference to FIG. 5. Possibly. the cardboard tape (27) can pass through an insertion station (48) for filler neck (17) in the form of plastic screw flanges in front of the station (33). In the station (33) the blanks (28) shown in FIG. 6 are then punched out of the cardboard tape (27) in a punch, after which the frames (8) are molded on. The end wall (4) thus created is inserted into the sleeve (2) in the station (33). The sleeve (2) is then already closed on one side with an end wall (4 or 16), but the filling opening (11) is open.

The sleeve (2) on the mandrel (31), into which the end wall (4 or 16) is already inserted, is then heated in the later seam area (10) in the stations (34, 35) with hot air. In the subsequent station (36), the end region (9) of the sleeve (2) can then be rolled around the frame (8) of the end wall (4 or 16). The following stations (37, 38) are used to form the sealing seam (10) between the sleeve (2) and the frame (8) of the end wall (4 or 16), this sealing seam (10) being pressed crosswise. The intermediate product formed from the sleeve (2) and inserted end wall (4 or 16), which is called a cup, can then be pushed off the mandrel (31) in the last station (39) of the sub-device (29) and transported further in the direction of the arrow (D) become.

9 shows the sub-device (49) assigned to the sub-device (29), and the feed path for the cups (52) supplied in the direction of the arrow (D) can be seen. The supplied cups (52) are first separated in a device (53), the cups (52) being transferred to the star wheel (50) rotating in cycles in the direction of the arrow (F) and inserted into a sleeve-like outer receptacle (51), which is circumferential the sleeve (2) attacks. Since a cup (52) in an external receptacle (51) is somewhat more difficult to handle than a sleeve (2) on a mandrel (31), it is advisable to use the end wall (3), which is simpler than the end wall (4 or 16), to be attached to the sub-device (49). The end wall forming the bottom (3) is inserted into the cup (52) in the next station (55). A roller (62) is provided for this, from which a cardboard tape (63) is drawn off and fed to the station (55) in the direction of the arrow (E). The station (55) contains a punch, in which the round blank for the end wall is punched and drawn, ie the frame (5) is molded on. In this station (55) the end wall (3) is inserted into the cup (52).

The subsequent stations (56, 57) serve to heat the seam area (7) with hot air. In the station (58) the end region (6) of the sleeve (2) is then rolled around the frame (5) of the end wall (3). The subsequent stations (59, 60) again serve to form the sealing seam (7), which is pressed crosswise. In the last station (61), the finished can (1 or 15) is finally pushed off and fed to a filling station in the direction of the arrow (G).

Claims (9)

1. Device for making a box of cardboard provided with a layer of thermoplastic material, having means for winding a case (2), said means comprising at least one mandrel (31) of a star wheel (30), and means for fitting and sealing two end walls (3, 4; 3, 16) to serve as bottom and cover, one of which is provided with a filling opening (11), and having further at least one holder (51) arranged on the means for fitting the second end wall (30) and engaging the circumference of the case (2), characterized in that the mandrel (31) for winding the case (2) is intended also for inserting the first end wall (4; 16) and that the holder (51) arranged on the means for inserting the second end wall (3) is provided at a second star wheel (50).
2. Device according to claim 1, characterized in that the first star wheel (30) can be rotated in a clocked way from a winding station (32) for the case (2) to a station (33) for fitting the first end wall (4; 16).
3. Device according to claims 1 and 2, characterized in that the station (33) for fitting the first end wall (4; 16) is provided with feeding means (A) for a carton strip (27).
4. Device according to any of claims 1 to 3, characterized in that a cutting means is assigned to the station (33) for fitting the first end wall (4; 16).
5. Device according to any of claims 1 to 4, characterized in that the cutting means is followed by a station for bending over the edge of the end walls (4; 16) to form a border (8).
6. Device according to claim 5, characterized in that the cutting means has assigned to it a fitting station (48) for a filling and discharge pipe end (17) that is especially provided with a screw thread (20).
7. Device according to any of claims 1 to 6, characterized in that the station (32, 33) for winding the case and for fitting the end walls (4; 16) has assigned to it hot-air nozzles for heating and sealing the seams.
8. Device according to any of claims 1 to 7, characterized in that the two star wheels (30, 50) are interconnected by a feeding track (arrow D).
9. Device according to any of claims 1 to 8, characterized in that the station (55) for fitting the second end wall (3) is provided with feeder means (E) for a carton strip (63).

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