This application is a 35 USC 371 of PCT/EP03/08734 filed Aug. 07, 2003.
The invention concerns an extruded composite profile, especially for use in a method for separately coiling two individual, simultaneously extruded tubes by means of a single coiling device.
To increase production capacity and to reduce the extrusion ratio in extruded profiles, it is well-known that multiple strands can be extruded. DE 31 31 155 C2 describes the production of a multiple extrusion of this type for use as hollow spacer sections for multipane glazings. In one embodiment, four hollow spacer profiles in the composite profile of a multiple extrusion are shown arranged parallel to one another. The connection is formed by a web, and its cross section is dimensioned in such a way that it remains dimensionally stable after leaving the extrusion die. To obtain the individual profiles, the webs are severed. For this purpose, weakening continuous notches are provided at the ends of the web wall. During the extrusion of straight lengths of these multiple strands, the latter are held by a drawing device and run to a length of typically 30 to 100 m. A quasi-continuous method for producing individual strands is not described. In a quasi-continuous method described in WO 00/23205, which involves extrusion with subsequent coiling, strand lengths of several hundred to several thousand meters are achieved. However, individual strands are generally extruded, since extrusion rate differences of the individual strands emerging from the individual die openings of the extrusion press cannot be compensated by the drawing device. Coiling several strands with one coiling device is then no longer possible due to the cumulative differences in strand length. The problem is typically solved by installing a number of independent coiling devices that corresponds to the number of die openings. This has the disadvantage of increased plant requirements. At the same time, the number of possible strands is limited due to the necessary space and die size.
The objective of the invention is to develop a method for coiling several simultaneously extruded profiles that is as cost-effective as possible.
This objective is achieved by a method in accordance with claim 1, in which an extruded composite profile is produced in a first process step. This extruded composite profile, which is extruded as a single piece, preferably is composed of aluminum or an aluminum alloy. It has at least two individual tubes, which are connected with each other by a thin, narrow junction. The individual tubes can have the same or different outside and inside geometries. In a preferred embodiment, the individual tubes have a flat profile cross section with two parallel broad sides and two convex narrow sides that join the broad sides, such that the individual tubes, which are arranged side by side, are connected with each other as a single piece by the junction in the radial region at the narrow sides. In an especially preferred composite profile, the individual tubes are connected by the junction at the radial vertex of each adjacent narrow side. Due to the connection of the individual tubes in the composite profile, the rate of extrusion of the individual strands during the extrusion process and thus the strand lengths are absolutely synchronized.
If necessary, after extrusion, the strand of the extruded composite profile can pass through a surface coating station with subsequent drying/hardening, and/or cooling. After the strand of the extruded composite profile has cooled, it passes through a speed regulation device, where said strand of the extruded composite profile is adjusted to a constant speed of passage before the connection of the individual tubes in the composite profile is severed in a separating device.
To facilitate this separation and to avoid deformation and damage of the individual tubes, the wall thickness of the junction must be smaller than the wall thicknesses of the adjacent individual tubes. It should be reduced by at least 20%. Furthermore, it was found to be advantageous for the width of the junction to be minimal, namely, 0.1 to 1.5 mm. A junction width smaller than 0.1 mm means that the walls of the individual tubes merge with each other. This necessarily leads to deformations of the walls of the individual tubes during separation. Although widths of the junction greater than 1.5 mm are possible, they are a disadvantage for the reason that after the extruded composite profile has been separated, residual material of the junction remains at the radius of the individual tubes, which forms a visible, unsightly seam and can be removed only by additional finishing work. In addition, in the case of large and relatively thick profiles, the junction can be provided with at least one predetermined breaking point, which further reduces the wall thickness of the junction.
The strands of the individual tubes can be separated in various ways, for example, by pulling them apart or breaking them apart. In the case of pulling them apart, the individual tube strands are pulled apart horizontally or vertically with respect to the arrangement of the individual tubes relative to each other. This can be realized in a separating device by the suitable arrangement of guide rollers.
In a different design, the separation operation of pulling the individual tubes apart is supported by the arrangement of a wedge-shaped tool at the separation site, so that reliable breaking apart of the junction is always effected at the same point.
In another design, the junction is not torn apart, but rather separation is effected solely by the wedge-shaped tool.
In an especially advantageous design variant, the separation is effected by single or repeated bending of the individual tubes about the junction. To carry out bending movements of this type, the strands of the extruded composite profile are guided through pairs of shaped rollers, such that the opposing shaped rollers have matching peripheral profiling, which corresponds to the desired bending deflections. If, for example, a planar extruded composite profile consisting of several individual tubes arranged side by side is being extruded, then a pair of shaped rollers that has zigzag profiling is to be used for breaking apart the junction of the individual tubes, so that a zigzag space for receiving the extruded composite profile is formed between the shaped rollers. After the formerly planar extruded composite profile has passed through the first pair of shaped rollers, the extruded composite profile, has been deformed into a zigzag cross section, in which the reversal points in the zigzag path are located at the junction. This single bending generally does not result in separation but rather causes strain hardening at the bending point due to the application of bending stress, i.e., material strengthening at the junction. This material strengthening of the junction facilitates a subsequent separation of the connection between the strands of individual tubes. It is also advantageous to employ a strain hardening step of this type in the above-described separating method involving the use of a wedge-shaped tool to pull apart or separate the individual strands.
Repeated bending back and forth then leads to the severing of the junctions between the individual tubes. Preferably, additional pairs of shaped rollers are used for this purpose, and in this case, the orientation of the upper roller and lower roller alternates in successive pairs of rollers.
In an especially preferred embodiment, a pair of cylindrically shaped rollers is arranged between each two successive pairs of shaped rollers. In this way, each pair of shaped rollers needs to carry out a maximum of one bending movement, starting from the planar extruded composite profile and bending it into a zigzag profile or, vice versa, starting from a zigzag, profile and bending it into a planar profile.
The number of bending movements needed for the separation depends on the wall thickness of the junction and on the nature of the material.
In the same way that a planar extruded composite profile can be separated into individual tubes by bending back and forth, this is also possible for an extruded composite profile with a zigzag shape or other shape.
To avoid deformation of the individual tubes during the bending operations, the individual tubes are subjected to a maximum bending deflection only as far as contact with the adjacent individual tube. The maximum upward bending angle of two individual tubes from their initial planar position is defined as the angle above the junction between the tangents that are in contact with the walls of the individual tubes, starting from the center of the junction. In the same way, the maximum downward bending angle of two individual tubes from their initial planar position is defined as the angle below the junction between the tangents that are in contact with the walls of the individual tubes, starting from the center of the junction. In the case of a connection of identical individual tubes at the radial vertex, the two bending angles have the same measure.
After the individual strands have been separated, they are guided apart and wound in separate winding regions, and these separate winding regions on one or more coils are driven by the drive of a coiling device. This means that only one coiling device is necessary, and thus the capital costs for an installation of this type can be kept at a low level.
Further details and advantages of the invention are specified in the dependent claims and in the following description of embodiments of the invention. However, the invention is not limited to these specific embodiments.
a shows a schematic drawing of another separating device.
b shows a sectional view of the respective pairs of rollers from
The individual tubes 20, 30 do not have to have a flat profile cross section. Other cross-sectional shapes are also possible, such as circular or oval individual tubes.
A further advantage of a composite profile of this type is that when the composite profile is installed in the motor vehicle, and the individual tubes 20′, 30′ are connected to the connectors provided for this purpose, the individual tubes 20′, 30′ that are still connected can, if necessary, be separated over a certain length by separation of the given junctions 40′, while in other areas the connection between the individual tubes 20′, 30′ in the composite profile can be preserved.
In the embodiment shown in
In the case of profiles and junctions with thicker walls, it is advantageous to provide the junctions 40 with one or two predetermined breaking points 42, 43, which are then preferably located in the center of the junction 40 and opposite each other. In
In
Depending on the intended application, as
As
The severing of the junction 40 can also be accomplished exclusively by the tool K, as
However, for a continuous process, the embodiments according to
A single bending generally does not cause separation of the junctions 40, so that it is necessary to bend the strands back and forth several times. It has been found to be advantageous to provide a pair of cylindrical rollers 50 between two pairs of profiled shaped rollers 53, 54. This facilitates the guiding of the strand of the composite profile 10 in the separating device (E).
In the case of very small bending deflections, a comparatively larger number of bending steps is necessary that in the case of larger bending deflections.
Composite profiles of the type shown in
It has been found that even only one bending is very advantageous for the separation, since the bending deformation leads to embrittlement at the junction. This type of material strengthening of the junction can also be advantageous in the above-described methods in accordance with
The individual strands of the individual tubes 20 and 30 are then further conveyed separately. As
In the embodiment shown in
It is, also possible to produce more than two strands in this way. Furthermore, it is possible to dispense with a coating of the composite profile in the coating device (B).
It is also possible to coil the composite profile 10 temporarily and then to uncoil it at a later time or, for example, to uncoil it in a different location after it has been shipped to a composite profile processor. In this case, the composite profile 10 emerging from the extrusion press (A) is wound on a coil, if necessary, after a coating and drying operation. The composite profile profile 10 is then uncoiled later and fed into a separating device (E). The separated strands are each fed separately to a coil of a coiling device.
Both methods are more cost-effective than previous methods.
Number | Date | Country | Kind |
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102 43 725 | Sep 2002 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP03/08734 | 8/7/2003 | WO | 00 | 3/18/2005 |
Publishing Document | Publishing Date | Country | Kind |
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WO2004/033122 | 4/22/2004 | WO | A |
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Number | Date | Country |
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31 31 155 | Feb 1983 | DE |
1 208 923 | May 2002 | EP |
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Number | Date | Country | |
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20050217340 A1 | Oct 2005 | US |