The invention relates to an apparatus for strip processing with at least one uncoiling station, at least one strip processing station and at least one coiling station.
Such apparatus are known in a plurality of configurations. If the strip processing consists in trimming a strip, for example, the strip is uncoiled from a coil in an uncoiling station, fed to the trimming station, trimmed by a trimming knife in the trimming station and then coiled onto a coil by a coiling station. In addition to trimming, generic devices for strip processing are also used for parting, cold rolling or the like.
During the manufacture of a strip, this strip is generally subjected to a plurality of roll passes. Over the majority of the strip width, the reduction in thickness during rolling leads to an increase in the length of the strip. Near the strip edges however, in addition to the effect of increasing strip length during rolling, there is also an increase in strip width. As a result of the increase in the width of the strip at the strip edge, less material is available for the increase in the strip length at the strip edge which has the result that a more or less high strip-edge stress appears in the strip. The strip-edge stress described results in various problems during further processing of the strip. During the manufacture of can-body strip, for example, which is processed to form drink-can bodies in further processing steps, as a result of the generally very high strip-edge stress in this strip, undesirable edge lengthening occurs during trimming as a result of friction of the cut edges on the trimming knife. This undesirable edge lengthening leads, on the one hand, to a so-called starburst or star pattern formation on the coiled coil and, on the other hand, results in poor machinability during the further processing.
Occasionally during the further processing of so-called can-lid strip some strip cracking occurs during the stretching carried out during the further processing, which may have its origin, among other things, in the fact that the strip edges of the can-lid strip supplied for further processing have a high strip-edge stress and thus favour cracking during stretching.
Finally, a high strip-edge stress during the rolling process has the result that during each roll pass, a higher rolling energy must be applied to overcome the strip-edge stress than would be needed if this strip-edge stress were completely reduced. Thus, if the strip-edge stress can be reduced during two passes, the rolling energy required on the second pass is reduced.
On the basis of the prior art described previously, the object of the invention is to provide an apparatus for strip processing which makes it possible to achieve a specific reduction in the strip-edge stress in a strip.
The object derived and indicated previously is solved according to the invention by providing between the uncoiling station and the coiling station, a strip-edge stretching station to stretch the edges of the strip. The strip-edge stretching station according to the invention offers the possibility of reducing the strip-edge stress to the desired extent or even specifically producing a strip-edge overstretching. By specifically reducing the strip-edge stress, the problems during strip processing known from the prior art, as described above, can be reduced or even completely eliminated.
The apparatus for strip processing according to the invention is especially suited to the processing of strips of aluminium materials since particularly high strip-edge stresses occur during the cold rolling of aluminium because of the strain-hardening properties of aluminium.
In the apparatus for strip processing according to the invention, the strip processing can especially consist exclusively in stretching the edges of the strip. However, it is generally advantageous to combine the stretching of the strip edges with at least one further processing step, for example, trimming the strip, in an apparatus for strip processing.
A possibility for constructing a strip-edge stretching station according to the invention would consist, for example, in subjecting the strip edges to a separate pass which preferably comprises no processing of the strip between the strip edges. It may be feasible to have an arrangement of two short rollers in the area of the strip edges which, for example, specifically roll the strip edges in cooperation with a guide roller in the rolling mill whereby the strip-edge stresses are reduced.
In practical testing it has proved to be particularly advantageous to have a configuration of the apparatus for strip processing according to the invention in which the strip-edge stretching station has two strip-edge stretching units which engage laterally into the strip and one strip-edge stretching unit which respectively has at least three strip-edge guide rollers. In such a strip-edge stretching station the strip edges are straightened not by running directly between the strip-edge guide rollers in the direction of strip transport but by being guided over the strip-edge guide rollers in a loop which results in stretching of the strip edges on account of the increased path length for the strip edges. The structure of such a strip-edge stretching station is very simple and can easily be integrated in existing apparatus for strip processing.
Since, according to a development of the invention, the strip-edge guide rollers can be adjusted with respect to one another substantially perpendicular to the plane of the strip, the loop forced over the strip-edge guide rollers can be adjusted whereby the degree of stretching is in turn adjustable.
If, according to a further development of the invention, the strip-edge guide rollers are constructed as truncated-cone-shaped, on the one hand the threading of the strip edges between the strip-edge guide rollers is simplified and on the other hand, it is ensured that an increasing stretching takes place towards the edge of the strip, whereby account is taken of the stress gradient in the strip edge. Naturally, other thickness profiles are also feasible for the strip-edge guide rollers, which are respectively matched to the desired stretching profile.
Since the strip-edge stretching devices are arranged in the plane of the strip, displaceable perpendicular to the strip running direction, the depth of immersion of the strip-edge guide rollers in the strip can be adjusted and thus the area of the strip edges which is stretched can be varied.
There are now a plurality of possibilities for configuring and further developing the apparatus for strip processing according to the invention. For this purpose reference is made, on the one hand, to the subsidiary claims to claim 1 and on the other hand, to the description of an embodiment in connection with the drawings, wherein
The section of an apparatus for strip processing according to the invention shown in
As can be seen from
Seen from the strip running direction,
Number | Date | Country | Kind |
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100 31 728 | Jun 2000 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCTEP01/07358 | 6/28/2001 | WO | 00 | 6/10/2003 |
Publishing Document | Publishing Date | Country | Kind |
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WO0200036 | 1/2/2003 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
2337047 | Hunter | Dec 1943 | A |
2969826 | Allen et al. | Jan 1961 | A |
3006401 | Wognum et al. | Oct 1961 | A |
3021737 | Titze | Feb 1962 | A |
3055241 | Hedgecock et al. | Sep 1962 | A |
3680343 | Singleton et al. | Aug 1972 | A |
3854315 | Winkler | Dec 1974 | A |
4033165 | Arimura et al. | Jul 1977 | A |
4329863 | Pryor et al. | May 1982 | A |
5341664 | Noe et al. | Aug 1994 | A |
Number | Date | Country |
---|---|---|
1752306 | May 1971 | DE |
04138805 | May 1992 | JP |
Number | Date | Country | |
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20040035173 A1 | Feb 2004 | US |