| 摘要 |
A gutter-shaped sectional bar (21) is bent on a three-roll bending machine, in such a way that its longitudinal centre surface (23) runs approximately parallel to the axes of rotation (9, 11, 13 ) of the rolls (3, 5, 7). The sectional bar (21), before running into the rolls (3, 5, 7), is guided and secured against rotation by guide jaws. A supporting member (61) has an elastically flexible mandrel part (69) and is held and guided by the rolls (3, 5, 7) in such a way that, in the region in which the sectional bar (21) is bent, the flexible mandrel part (69) supports relative to one another the sectional-bar halves located on different sides of the longitudinal centre surface (23). This makes it possible to bend the gutter-shaped sectional bar (21) into a spiral, without any appreciable deformation of the section. <IMAGE>
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