EP0456011A1 - Device for making a box of cardboard provided with a layer of thermoplastic material - Google Patents

Abstract

A device is provided, with which both end walls are inserted in a sealed manner and using hot air, one of the end walls being provided with an opening which serves as filling opening. <IMAGE>

Description

The invention relates to a device for producing a can from plastic-coated cardboard according to the preamble of patent claim 1.

DE 30 23 835 A1 shows and describes a can 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 filling material is 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 affect 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 in the introduction so 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 flawlessly, whereby, as in other similar manufacturing processes, it is sufficient, for example, to use hot air to seal the seams. There is no risk 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. This mandrel can be part of a star wheel according to the features of claim 3, which is cyclically rotatable 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 in a simple manner with the prefabricated filling openings at such a distance from one another that it is sufficient according to the features of claim 5, the station for Insert the first end wall to assign a cutting device with which only round blanks are punched out of the cardboard tape, which are then provided with a frame according to 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 7, 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 that is still unlocked,

Fig. 2

2 shows a longitudinal section through another can made 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

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.

Fig. 1 shows a first embodiment of a can (1) manufactured 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 tear-open tab can be attached after the can (1) has been completed, but before it has been filled, but the tear-open 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 can (15) according to FIG. 2 represents another embodiment according to the invention and differs from the can (1) of FIG. 1 essentially in that another end wall (16) is used in the can (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 areas (7, 10) 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 a substantially 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 in 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 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 in turn has the cut edge protection forms. The end wall (4) according to FIG. 7 already has the drawn frame (8).

FIGS. 8 and 9 show a device for the production of 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.

The sub-device (29) according to FIG. 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), supplies 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 off the later inner cutting edge (22). The later 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 jacket (46) is then obtained, the areas of the cut edges (22, 23) of which are sufficiently heated that the jacket (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 screw flanges made of plastic 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) located on the mandrel (31), into which the end wall (4 or 16) is already inserted, is then heated with hot air in the later seam area (10) in the stations (34, 35). 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 subsequent 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 in the direction of the arrow (D) will.

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 design 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 following stations (56, 57) serve to heat the seam area (7) with hot air. The end region (6) of the sleeve (2) is then rolled around the frame (5) of the end wall (3) in the station (58). 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 (10)

Device for producing a can from plastic-coated cardboard, with a device for winding a sleeve and with devices for inserting and sealing at least one end wall serving as a base or lid, characterized by devices (31, 33; 51, 55) for inserting both end walls ( 3; 4, 16), by inserting an end wall (4; 16) provided with a filling opening (11) on one of these devices (31, 33) and by at least one holder (51) engaging on the circumference of the sleeve (2), which is arranged on the device (55) for inserting the second end wall (3). Apparatus according to claim 1, characterized in that a mandrel (31) is provided for winding the sleeve (2) and for inserting the first end wall (4; 16). Apparatus according to claim 2, characterized in that the mandrel (31) is part of a star wheel (29) which is clocked from a winding station (32) for the sleeve (2) to a station (33) for inserting the first end wall (4; 16) is rotatable. Device according to claim 3, characterized in that the station (33) for inserting the first end wall (4; 16) is provided with a conveying device (A) for a cardboard tape (27). Device according to one of claims 1 to 4, characterized in that a cutting device is assigned to the station (33) for inserting the first end wall (4; 16). Device according to one of claims 1 to 5, characterized in that the cutting device is followed by a station for bending the edge of the end walls (4; 16) into a frame (8). Apparatus according to claim 6, characterized in that the cutting device is assigned an insertion station (48) for a filling and emptying nozzle (17) which is in particular provided with a screw thread (20). Device according to one of claims 1 to 7, characterized in that the station (32, 33) for winding the sleeve and for inserting the end walls (4; 16) are assigned hot air nozzles for heating and sealing the seams. Device according to one of claims 3 to 8, characterized in that the first star wheel (29) is followed by a second star wheel (49) with the holder (51) on which the can (1; 15) with the opening (11 ) is completed. Device according to claim 9, characterized in that the station (55) for inserting the second end wall (3) is provided with a conveyor device (E) for a cardboard tape (63).

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