CA2502197A1

CA2502197A1 - Device for sealing a cover element into a casing part of a packaging body made of composite material

Info

Publication number: CA2502197A1
Application number: CA002502197A
Authority: CA
Inventors: Dirk Auer
Original assignee: Individual
Current assignee: SIG Combibloc Services AG
Priority date: 2002-11-29
Filing date: 2003-09-27
Publication date: 2004-06-17
Also published as: DE50304249D1; US20060130429A1; ATE332795T1; ES2268489T3; MXPA05005112A; JP2006510516A; EP1565305B1; AU2003276000A1; EP1565305A1; PL375502A1; WO2004050333A1

Abstract

The invention relates to a device for sealing a cover element into a casing part of a packaging body made of composite material. The aim of the inventio n is to provide a device of the aforementioned type with which the sealing process should ensure in as few steps as possible, and to enable the device to be easily adapted to different cross-sectional shapes of the casing part. To these ends: an inductor ring (3) is provided; the inductor ring (3) encircle s the casing part and is adapted to the course of the periphery of the casing part; the inductor ring (3) has at least two segments (4, 5, 6, 7) that form a ring; the segments (4, 5, 6, 7) can be displaced in the plane of the cover element whereby enabling the cross-sectional area enclosed by the segments ( 4, 5, 6, 7) to be altered; at least one first joint (10) between two segments ( 4, 7) is provided so that it is electrically non-conductive, and; the other joints (11) are provided so that, regardless of the relative position of the segments (4, 5, 6, 7) to one another, an electrical contact exists between adjacent segments (4, 5, 6, 7).

Description

TH/bs 020756WOX
08. April 2005 DEVICE FOR SEALING A CAP ELEMENT INTO A CASING PART OF A
PACKAGING BODY MADE OF COMPOSITE MATERIAL
The present invention relates to a device for sealing a cap element into a casing part of a packaging body made of composite material.
A device for producing a packaging body made of composite material, the packaging body having a casing part and two cap elements inserted at the ends, is known from German Patent Application 40 14 774 A1. The composite material comprises a plastic-coated paper and an aluminium layer or a layer made of another electrically conductive material.
A packaging body of this type is produced using the device described therein by first forming the casing part, in that the diametrically opposite edges of a sheet made of composite material are bonded to one another using a sealing seam. The selection of the cross-sectional shape is arbitrary in the production of the casing part. In the simplest case, it may be a rectangular or circular cross-section, however, other cross-sectional shapes are also conceivable.
Cap elements are inserted into the ends of the casing part, while the casing part is held by a mandrel whose cross-section corresponds to that of the easing part. The cap elements already have an edge notch which runs TH/bs 020756WOX

parallel to the wall of the casing part. After the insertion of the cap element, the end region of the casing part is bent around the edge notch.
In addition, the end region of the casing part is heated using hot air and a sealing seam is formed on the ends through subsequent pressing of the already bent region, so that the cap element is sealed into the ends of the casing part.
A device of this type has the disadvantage that multiple steps are required to form the sealing seam on the ends after the bending. First, the end region of the casing part must be heated using hot air and only then may the pressing be performed. A comparatively complicated device is connected therewith. Furthermore, the danger of damage to the composite material through overheating arises due to the heating using hot air. In addition, different cross-sectional shapes for the casing part may be processed only after complex reconfigurations, since not only the mandrel but also the entire pressing device must be changed.
On the basis of this prior art, the present invention is based on the object of providing a device for sealing a cap element into a casing part of a packaging body made of composite material, the sealing procedure to be performed in as few steps as possible and the device able to be adapted easily to different cross-sectional shapes of the casing part.
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This object is achieved according to the present invention in that an inductor ring is provided, the inductor ring encloses the casing part and is tailored to the shape of the circumference of the casing part, the inductor ring includes at least two segments which form a ring, the segments are displaceable in the plane of the cap element in such a way that the cross-sectional area enclosed by the segments is changeable, a first joint between two segments is electrically implemented in such a way that no electrical contact exists between the neighboring segments at the first joint, and the further joints are implemented so that an electrical contact exists between neighboring segments independent of the relative position of the segments to one another.
According to the present invention, eddy currents may be induced in the aluminium layer and/or a layer made of another conductive material in the composite material in the region of the sealing seam using the inductor ring, which may have a high frequency field applied to it, which leads to heating. The simultaneous displaceability of the segments allows the inductor ring to be transferred from an open position to a closed position through displacement of the segments. During the transfer into the closed position, pressing of the cap element with the casing part may occur during the heating.
In order for the high frequency field to completely permeate the inductor ring independently of its position, it is necessary for the joint between the segments to which the high frequency field is applied to be implemented as insulating. The further joints between the TH/bs 020756WOX

remaining segments must then be implemented as electrically conductive.
According to a further teaching of the present invention, sliders are provided, which may have a force, which is directed onto the casing part, applied to them via pistons. The segments may then be attached to the sliders, which makes replacement of the segments easier if the cross-sectional shape of the casing part changes.
If four segments, which are displaceable along lines positioned perpendicularly to one another, are provided, symmetrical pressing is made possible.
In a further preferred embodiment, four symmetrically arranged pistons which may have pressure applied to them are provided, which allows uniform application of a force, directed onto the casing part, onto the sliders.
If the pistons have pressure applied to them via a shared line, especially simple setting of a pressure which is constant over the course of the sealing seam is made possible.
The sliders are preferably pre-tensioned in a direction pointing away from the casing part, so that the segments automatically move away from the casing part when the pistons no longer have pressure applied to them.
Lever arms are preferably used to transmit force from the pistons onto the sliders, which primarily allows compact construction of the device. If two lever arms are linked to each slider, reliable force transmission is ensured.
If each piston presses against the two ends of two lever TH/bs 020756wOX

arms and these two lever arms are linked to two different sliders, it is ensured that all of the sliders and therefore all of the segments have a force applied to them uniformly.
In a further embodiment of the present invention, at the first joint, independent of the positions of the segments, there is a distance between the segments neighboring thereto. In this way, reliable insulation is ensured. In particular, abrasion possibly arising as a result of the movement of the segments does not result in impairment of insulation.
If, according to a preferred embodiment, the segments are formed by multiple lamellae positioned one on top of another, the possibility of multiple contact surfaces on the further joints results, especially good contact being ensured with the lowest possible resistance if these joints are implemented as brackets pointing outward. This resistance is then also independent of the position of the segments in relation to one another.
The present invention will be described in the following in greater detail on the basis of an exemplary embodiment which represents a preferred embodiment of a device according to the present invention. In the drawing:
Figure 1 shows the device in cross-section from the side, Figure 2 shows the device in horizontal section along the line II-II from Figure l, TH/bs 020756WOX

Figure 3 shows the device in horizontal section along the line III-III from Figure 1, Figure 4 shows the inductor ring in the open position in a top view, Figure 5 shows the inductor ring in the closed position.
in a top view, Figure 6 shows a part of the open inductor ring in sectional view along the line VI-VI from Figure 4, Figure 7 shows a part of the open inductor ring in sectional view along the line VII-VII from Figure 4, Figure 8 shows a part of the closed inductor ring along the line VIII-VIII from Figure 5, and Figure 9 shows a part of the closed inductor ring in sectional view along the line IX-IX from Figure 5.
As shown in Figures 1 and 2, the device has a holder 1 which has a circular cross-section. Pins 2, which are used for the purpose of fastening the device to a suspension, are attached to the top of the holder 1. The inductor ring 3, which includes four segments 4, 5, 6, 7, is attached to the lower part of the holder 1 (Figures 2 and 4). The segments 4, 5, 6, 7 may enclose the cross-TH/bs 020756WOX

sectional area of a casing part (not shown). The shape of the edges of the segments 4, 5, 6, 7 facing inward is tailored to the shape of the circumference of the casing part. In this case, the cap element is inserted into the end of the casing part in such a way that the edge notch of the cap element is at the height of the inductor ring 3. The inductor ring 3 is therefore located in the plane of the cap element.
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_ g The segments 4, 5, 6, 7 are displaceably attached in the holder 1, so that the cross-sectional area which they enclose is changeable. The segments 4, 5, 6, 7 may be transferred in this case from an open position (Figure 4) into a closed position (Figure 5), the enclosed cross-sectional area being smaller in the closed position.
There is a first joint 10 between the segments 4 and 7, which is implemented as electrically insulating. The further joints 11 between the remaining segments, in contrast, are implemented as electrically conductive.
Contact elements 8, to which a high frequency field may be applied, are provided on the segments 4 and 7, which adjoin the first joint 10. In order that the high frequency field may permeate the entire inductor ring 3, it is necessary for the first joint 10 to be implemented as insulating and the further joints 11 to be implemented as electrically conductive.
The segments 4, 5, 6, 7 also have mounting brackets 9, using which the segments 4, 5, 6, 7 may be attached to sliders 13 via pins 12. The sliders 13 have holes 14 and are displaceably attached in the lower part of the holder 1. In this case, the four sliders 13 may be displaced along a first line 15 and a second line 16, the first line 15 and the second line 16 enclosing an angle of approximately 90° and lying in the plane of the cap element.
Four pistons 17, which are guided in four cylinders 18, are provided in the holder 1 above the inductor ring 3.
The four cylinders 18 are positioned in such a way that TH/bs 020756WOX

the pistons 17 are displaceable along four lines which extend perpendicularly to one another in a cross shape outward from the center of the holder 1. The cylinders 18 each have a pressure line 19A on their floor surface facing toward the middle of the holder 1, which discharge into the shared pressure line 19B, which is positioned in the center of the holder 1 and points upward.
As may be seen from Figure 3, eight lever arms 20 are positioned in the upper part of the holder 1. The lever arms 20 have a first end 21 and a second end 22 and may be pivoted around pivot axes 23. In this case, the pivot axes 23 run perpendicular to the plane of the cap element. The ends of the pistons 17 pointing away from the center of the holder 1 press against the second ends 22 of the lever arms 20. In this case, each piston 17 presses against two second ends 22 of two different lever arms 20. The first ends 21 of the lever arms 20 are linked via axles 24 to the sliders 13, the axles 24 running through the holes 14 in the sliders 13. The first ends 21 of each two lever arms 20 are linked to one slider 13 by a shared axle 24, the second ends 22 of these lever arms able to have pressure applied to them by two different pistons 17. Through this connection between two pistons 17 and a slider 13 and vice versa, the pressure is uniformly transmitted to the segments 4, 5, 6, 7, through which a constant pressure along the sealing seam is achieved.
Furthermore, springs 25 are provided, through which the first ends 21 of the lever arms 20 are pre-tensioned in the direction pointing away from the casing part. In this TH/bs 020756WOX

way, the sliders 12 are also pre-tensioned in this direction.
As may be seen from Figures 6 through 9, the segments 4, 5, 6, 7 are assembled from lamellae 26 positioned one on top of another. In this case, the first joint 10 is implemented in such a way that a distance is provided between the segments 4 and 7, which adjoin the first joint 10 and are therefore neighboring, both in the open state of the inductor ring 3 (Figure 7) and in the closed state (Figure 9). Through this continuously existing distance, it is ensured that the first joint 10 between the segments 4 and 7 is implemented as electrically insulating independently of the state of the inductor ring 3 and that the high frequency field applied to the contact elements 8 may completely permeate the inductor ring 3.
Brackets 27, which point outward from the casing part in the plane of the cap element, are implemented on the lamellae 26 at the further joints 11 (Figures 4 and 5).
These brackets 27 have contact surfaces 28, which lie on top of one another both in the open state of the inductor ring 3 (Figure 6) and in the closed state (Figure 8).
Therefore, electrical contact is provided continuously at the further joints 11, independently of the position of the segments 4, 5, 6, 7 in relation to one another.
To seal a cap element into a casing part of a packaging body, the cap element having the edge notch is first placed on a shaping mandrel. The casing part is then shaped around the mandrel and the lengthwise seam is TH/bs 020756WOX

produced. This prefinished packaging body is supplied to the device according to the present invention.
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The holder 1 having the inductor ring 3 on its lower end is then pushed over the upper end of the casing part having the cap element. While the holder 1 having the inductor ring 3 is pushed on, the pistons 17 do not have pressure applied to them. Due to the pre-tension by the springs 25, the sliders 13 are pressed outward, so that the inductor ring 3 is in the open position shown in Figure 4. After the holder 1 is pushed on, the edge notch of the cap element is at the height of the inductor ring 3. The pistons 17 then have pressure applied to them via the pressure lines 19A and 19B. In this way, the second ends 22 of the lever arms 20 are pressed outward. This has the result that the sliders 13 are pressed in the direction of the casing part via the first ends 21 of the lever arms 20. Therefore, the segments 4, 5, 6, 7 move toward one another along the first line 15 and the second line 16, so that the cross-sectional area enclosed by the inductor ring 3 is reduced. The inductor ring 3 is thus transferred into the closed position.
While the pistons have pressure applied to them, a high frequency field is simultaneously applied to the contact elements 8 of the segments 4 and 7, through which eddy currents are induced in the aluminium layer inside the composite material. This leads to heating of the aluminium layer and therefore of the composite material and, due to the pressure applied, a sealing seam is formed between the edge notch of the cap element and the casing part. The heating and pressing are therefore performed in a shared method step. After termination of the sealing procedure, the high frequency field is switched off and the pistons 17 no longer have pressure TH/bs 020756WOX

applied to them. Therefore, since the sliders 12 are pre-tensioned by the springs 25, the sliders 12 are pressed outward by them, away from the casing part, and therefore the inductor ring 3 is transferred into the open position. As may be seen from Figures 4 and 5, the first joint 10 and the further joints 11 are implemented as insulating and conducting, respectively, both in the closed and in the open position of the inductor ring 3.
Therefore, the inductor ring may continuously have a high frequency applied to it while it is closed and the composite material may thus be heated while the pressing occurs simultaneously. This allows a high quality of the sealing seam.
As may be seen from Figure 2 in particular, the device according to the present invention may easily be tailored to a changed cross-section of the casing part. For this purpose, it is merely necessary to remove the pins 12 and replace the segments 4, 5, 6, 7 with new segments tailored to the changed cross-sectional shape. The remaining part of the device, in contrast, may remain unchanged.
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Claims

1. A device for sealing a cap element into a casing part of a packaging body made of composite material, characterized in that an inductor ring (3) is provided, the inductor ring (3) encloses the casing part and is tailored to the shape of the circumference of the casing part, the inductor ring (3) includes at least two segments (4, 5, 6, 7), which form a ring, the segments (4, 5, 6, 7) are displaceable in the plane of the cap element in such a way that the cross-sectional area enclosed by the segments (4, 5, 6, 7) is changeable, a first joint (10) between two segments (4, 7) is implemented as electrically insulating, so that no electrical contact exists between the neighboring segments (4, 7) at the first joint (10), and the further joints (11) are implemented in such a way that, independent of the relative position of the segments (4, 5, 6, 7) to one another, electrical contact exists between neighboring segments (4, 5, 6, 7).

2. The device according to Claim 1, characterized in that the inductor ring (3) includes four segments (4, 5, 6, 7).

3. The device according to Claim 2, characterized in that two segments (5, 7) are displaceable along the first line (15) toward the casing part and two segments (4, 6) are displaceable along a second line (16) toward the casing part.

4. The device according to Claim 3, characterized in that the first line (15) and the second line (16) enclose an angle of approximately 90° to another.

5. The device according to one of Claims 1 through 4, characterized in that the device has sliders (13) and the segments (4, 5, 6, 7) are attached to the sliders (13).

6. The device according to one of Claims 1 through 5, characterized in that the device has pistons (17) which are guided along lines pointing essentially away from the casing part.

7. The device according to Claim 6 or 7, characterized in that four pistons (17) are provided.

8. The device according to Claim 7, characterized in that the sliders (13) may have a force which points in the direction of the casing part applied to them by the pistons (17).

9. The device according to one of Claims 6 through 8, characterized in that the pistons (17) may have pressure applied to them.

10. The device according to Claim 9, characterized in that the pistons (17) may have pressure applied to them via a shared pressure line (19B).

11. The device according to one of Claims 5 through 10, characterized in that the sliders (13) are pre-tensioned in a direction pointing away from the casing part.

12. The device according to one of Claims 5 through 11, characterized in that the sliders (13) are pre-tensioned using a spring (25).

13. The device according to one of Claims 5 through 12, characterized in that the device has lever arms (20) having a first end (21) and a second end (22), and the first ends are linked to the sliders (13) and the lever arms (20) are pivotable around pivot axes (23) provided between the ends (20, 21).

14. The device according to Claim 13, characterized in that two lever arms (20) with their first ends (21) are linked to one slider (13).

15. The device according to Claim 14, characterized in that the first ends (21) of the lever arms (20) are linked to the slider (13) using a shared axle (24).

16. The device according to one of Claims 13 through 15, characterized in that the pistons (17) press against the second ends (22) of the lever arms (20).

17. The device according to Claim 16, characterized in that one piston (17) presses against the second ends (22) of two lever arms (20), and the two lever arms (20) are linked to two sliders (13).

18. The device according to one of Claims 13 through 17, characterized in that the second ends (22) of the lever arms (20) may have a force pointing essentially away from the casing part applied to them by the piston (17).

19. The device according to one of Claims 1 through 18, characterized in that the segments (4, 7) which are positioned neighboring the first joint (10) each have a contact element (8).

20. The device according to one of Claims 1 through 19, characterized in that the segments (4, 7) neighboring the first joint (10) have a distance to one another, independent of the position of the segments (4, 5, 6, 7).

21. The device according to one of Claims 1 through 20, characterized in that the segments (4, 5, 6, 7) have multiple lamellae (26) which are positioned one over another.

22. The device according to Claim 21, characterized in that the lamellae (26) have contact surfaces (28) in the region of the further joints (11).

23. The device according to Claim 22, characterized in that the contact surfaces (28) of the lamellae (26) of a segment (6, 7) neighboring a further joint (11) rest on the contact surfaces (28) of the lamellae (26) of the other segment (6, 7) neighboring the further joint (11).

24. The device according to Claim 22 or 23, characterized in that the contact surfaces (28) are implemented as brackets (27) pointing outward on the lamellae (26).