| 摘要 |
PROBLEM TO BE SOLVED: To prevent any strain in a corner part from occurring. SOLUTION: With a corner forming part 16 formed by means of die forming, both horizontal and vertical members 12 and 14 different in depth of side wall parts 20 and 28 with each other are connected into being almost right angled. A side wall part 32 is bent along a position where depth from a tip of this side wall part 32 of the corner forming part 16 become identical to that of the side wall part 20 of the horizontal member 12, and a bending piece 36 at the corner inner circumferential side from this bent position is tilted to the outside at the same angle. |
