| 摘要 |
PURPOSE:To easily execute various kinds of bending from large radius of curvature to small radius of curvature with good productivity by connecting projecting parts formed between each adjacent edge in the bottom part with acute angles to the bottom part. CONSTITUTION:By connecting the projecting parts 4 to the bottom part 1 with the acute angles, opening parts in the projecting parts 4 are made to narrow to the inner part, and as the extreme form thereof, by nearly bringing the edge parts 2a-2b in the bottom part 1 into contact state with the adjacent edges, the projecting part 4 is made to form perfect cell unit with only itself. By this method, as connect angle between the bottom part 1 and the protruded part 4 becomes acute angle, rigidity at the corner part is made to high. As a result, the excellent productivity is obtd., and not only the various kinds of bendings from the large radius of curvature to the small radius of curvature can be easily executed, but also this method is suitable to form complicate shape, such as complex curved surface, which two or more curved faces are continued. |
