US20060130429A1 - Device for sealing a cover element into a casing part of a packaging body made of composite material - Google Patents

Abstract

A device for sealing a cap element into a casing part of a packaging body made of composite material is shown and described. The present invention is based on the object of providing a device of this type, 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. This object is achieved 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 implemented as electrically insulating, so that no electrical contact exists between the neighboring segments at the first joint, and the further joints are implemented in such a way that, independent of the relative position of the segments to one another, electrical contact exists between neighboring segments.

Description

• 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 casing part. The cap elements already have an edge notch which runs 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.
• 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 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 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:
• FIG. 1 shows the device in cross-section from the side,
• FIG. 2 shows the device in horizontal section along the line II-II fromFIG. 1,
• FIG. 3 shows the device in horizontal section along the line III-III fromFIG. 1,
• FIG. 4 shows the inductor ring in the open position in a top view,
• FIG. 5 shows the inductor ring in the closed position in a top view,
• FIG. 6 shows a part of the open inductor ring in sectional view along the line VI-VI fromFIG. 4,
• FIG. 7 shows a part of the open inductor ring in sectional view along the line VII-VII fromFIG. 4,
• FIG. 8 shows a part of the closed inductor ring along the line VIII-VIII fromFIG. 5, and
• FIG. 9 shows a part of the closed inductor ring in sectional view along the line IX-IX fromFIG. 5.
• As shown inFIGS. 1 and 2, the device has aholder1 which has a circular cross-section.Pins2, which are used for the purpose of fastening the device to a suspension, are attached to the top of theholder1. Theinductor ring3, which includes foursegments4,5,6,7, is attached to the lower part of the holder1 (FIGS. 2 and 4). Thesegments4,5,6,7 may enclose the cross-sectional area of a casing part (not shown). The shape of the edges of thesegments4,5,6,7 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 theinductor ring3. Theinductor ring3 is therefore located in the plane of the cap element.
• Thesegments4,5,6,7 are displaceably attached in theholder1, so that the cross-sectional area which they enclose is changeable. Thesegments4,5,6,7 may be transferred in this case from an open position (FIG. 4) into a closed position (FIG. 5), the enclosed cross-sectional area being smaller in the closed position.
• There is afirst joint10 between thesegments4 and7, which is implemented as electrically insulating. Thefurther joints11 between the remaining segments, in contrast, are implemented as electrically conductive.Contact elements8, to which a high frequency field may be applied, are provided on thesegments4 and7, which adjoin thefirst joint10. In order that the high frequency field may permeate theentire inductor ring3, it is necessary for thefirst joint10 to be implemented as insulating and thefurther joints11 to be implemented as electrically conductive.
• Thesegments4,5,6,7 also havemounting brackets9, using which thesegments4,5,6,7 may be attached tosliders13 viapins12. Thesliders13 haveholes14 and are displaceably attached in the lower part of theholder1. In this case, the foursliders13 may be displaced along afirst line15 and asecond line16, thefirst line15 and thesecond line16 enclosing an angle of approximately 90° and lying in the plane of the cap element.
• Fourpistons17, which are guided in fourcylinders18, are provided in theholder1 above theinductor ring3. The fourcylinders18 are positioned in such a way that thepistons17 are displaceable along four lines which extend perpendicularly to one another in a cross shape outward from the center of theholder1. Thecylinders18 each have apressure line19A on their floor surface facing toward the middle of theholder1, which discharge into the sharedpressure line19B, which is positioned in the center of theholder1 and points upward.
• As may be seen fromFIG. 3, eightlever arms20 are positioned in the upper part of theholder1. Thelever arms20 have afirst end21 and asecond end22 and may be pivoted around pivot axes23. In this case, the pivot axes23 run perpendicular to the plane of the cap element. The ends of thepistons17 pointing away from the center of theholder1 press against the second ends22 of thelever arms20. In this case, eachpiston17 presses against two second ends22 of twodifferent lever arms20. The first ends21 of thelever arms20 are linked viaaxles24 to thesliders13, theaxles24 running through theholes14 in thesliders13. The first ends21 of each twolever arms20 are linked to oneslider13 by a sharedaxle24, the second ends22 of these lever arms able to have pressure applied to them by twodifferent pistons17. Through this connection between twopistons17 and aslider13 and vice versa, the pressure is uniformly transmitted to thesegments4,5,6,7, through which a constant pressure along the sealing seam is achieved.
• Furthermore, springs25 are provided, through which the first ends21 of thelever arms20 are pre-tensioned in the direction pointing away from the casing part. In this way, thesliders12 are also pre-tensioned in this direction.
• As may be seen fromFIGS. 6 through 9, thesegments4,5,6,7 are assembled fromlamellae26 positioned one on top of another. In this case, the first joint10 is implemented in such a way that a distance is provided between thesegments4 and7, which adjoin the first joint10 and are therefore neighboring, both in the open state of the inductor ring3 (FIG. 7) and in the closed state (FIG. 9). Through this continuously existing distance, it is ensured that the first joint10 between thesegments4 and7 is implemented as electrically insulating independently of the state of theinductor ring3 and that the high frequency field applied to thecontact elements8 may completely permeate theinductor ring3.
• Brackets27, which point outward from the casing part in the plane of the cap element, are implemented on thelamellae26 at the further joints11 (FIGS. 4 and 5). Thesebrackets27 havecontact surfaces28, which lie on top of one another both in the open state of the inductor ring3 (FIG. 6) and in the closed state (FIG. 8).
• Therefore, electrical contact is provided continuously at thefurther joints11, independently of the position of thesegments4,5,6,7 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 produced. This prefinished packaging body is supplied to the device according to the present invention.
• Theholder1 having theinductor ring3 on its lower end is then pushed over the upper end of the casing part having the cap element. While theholder1 having theinductor ring3 is pushed on, thepistons17 do not have pressure applied to them. Due to the pre-tension by thesprings25, thesliders13 are pressed outward, so that theinductor ring3 is in the open position shown inFIG. 4. After theholder1 is pushed on, the edge notch of the cap element is at the height of theinductor ring3. Thepistons17 then have pressure applied to them via thepressure lines19A and19B. In this way, the second ends22 of thelever arms20 are pressed outward. This has the result that thesliders13 are pressed in the direction of the casing part via the first ends21 of thelever arms20. Therefore, thesegments4,5,6,7 move toward one another along thefirst line15 and thesecond line16, so that the cross-sectional area enclosed by theinductor ring3 is reduced. Theinductor ring3 is thus transferred into the closed position.
• While the pistons have pressure applied to them, a high frequency field is simultaneously applied to thecontact elements8 of thesegments4 and7, 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 thepistons17 no longer have pressure applied to them. Therefore, since thesliders12 are pre-tensioned by thesprings25, thesliders12 are pressed outward by them, away from the casing part, and therefore theinductor ring3 is transferred into the open position. As may be seen fromFIGS. 4 and 5, the first joint10 and thefurther joints11 are implemented as insulating and conducting, respectively, both in the closed and in the open position of theinductor ring3. 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 fromFIG. 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 thepins12 and replace thesegments4,5,6,7 with new segments tailored to the changed cross-sectional shape. The remaining part of the device, in contrast, may remain unchanged.

Claims (26)

1-24. (canceled)

25. A device for sealing a cap element into a casing part of a packaging body made of composite material, comprising:

an inductor ring, wherein the inductor ring encloses the casing part and is tailored to the shape of a circumference of the casing part, the inductor ring including at least two segments, which form a ring, wherein the segments are displaceable in a plane of the cap element in such a way that a cross-sectional area enclosed by the segments is changeable, a first joint between two segments is implemented as electrically insulating so that no electrical contact exists between neighboring segments at the first joint, wherein further joints are implemented in such a way that, independent of the relative position of the segments to one another, electrical contact exists between neighboring segments.

26. The device according toclaim 25, wherein the inductor ring includes four segments.

27. The device according toclaim 26, wherein two segments are displaceable along a first line toward the casing part and two segments are displaceable along a second line toward the casing part.

28. The device according toclaim 27, wherein the first line and the second line enclose approximately a right angle to one another.

29. The device according toclaim 25, wherein the device has sliders and the segments are attached to the sliders.

30. The device according toclaim 25, wherein the device has pistons which are guided along lines pointing essentially away from the casing part.

31. The device according toclaim 30, wherein four pistons are provided.

32. The device according toclaim 29, wherein the device has pistons which are guided along lines pointing essentially away from the casing part.

33. The device according toclaim 30, wherein the pistons have pressure applied to them.

34. The device according toclaim 33, wherein the pistons have pressure applied to them via a shared pressure line.

35. The device according toclaim 29, wherein the sliders are pre-tensioned in a direction pointing away from the casing part.

36. The device according toclaim 29, wherein the sliders are pre-tensioned using a spring.

37. The device according toclaim 29, wherein the device has lever arms having a first end and a second end, and wherein the first ends are linked to the sliders and the lever arms are pivotable around pivot axes provided between the ends.

38. The device according toclaim 37, wherein two lever arms with their first ends are linked to one slider.

39. The device according toclaim 38, wherein the first ends of the lever arms are linked to the slider using a shared axle.

40. The device according toclaim 37, wherein the pistons press against the second ends of the lever arms.

41. The device according toclaim 40, wherein one piston presses against the second ends of two lever arms, and the two lever arms are linked to two sliders.

42. The device according toclaim 37, wherein the second ends of the lever arms have a force pointing essentially away from the casing part applied to them by the piston.

43. The device according toclaim 25, wherein the segments, which are positioned neighboring the first joint, each have a contact element.

44. The device according toclaim 25, wherein the segments neighboring the first joint have a distance to one another independent of the position of the segments.

45. The device according toclaim 25, wherein the segments have multiple lamellae which are positioned one over another.

46. The device according toclaim 45, wherein the lamellae have contact surfaces in the region of the further joints.

47. The device according toclaim 46, wherein the contact surfaces of the lamellae of a segment neighboring at least one further joint rest on the contact surfaces of the lamellae of the other segment neighboring the at least one further joint.

48. The device according toclaim 46, wherein the contact surfaces are implemented as brackets pointing outward on the lamellae.

49. The device according toclaim 32, wherein the sliders may have a force which points in the direction of the casing part applied to them by the pistons.

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