| 摘要 |
PURPOSE:To adjust easily a bending pressure to uniform one throughout the whole length of a sheet material by dividing a movable upper die in its longitudinal direction to obtain plural segmental dies and providing a pressing means for pressing downward the segmental die by a hydraulic pressure to the upper part of the die in a punch holder. CONSTITUTION:A movable upper die 17 is divided into plural segmental dies 21 in its longitudinal direction, and a pressing means 25 for only the leftmost segmental die 21 is provided separately from the means 25 of the other segmental dies 21. When a sheet material of optional length has a bending length of 6.3/4l1 with respect to a length (l1) of each segmental die 21, the flat end part 3/4l1 of material 19a is positioned under the die 21 at the left end; and a hydraulic pressure P2 to be provided to the independent pressing means at the left end is set as expressed by an equation when a hydraulic pressure introduced to the pressing means at the right end is set to P1. In the same way, when a sheet material 19b has a 3.1/2l1 length, the pressure P2 is adjusted to P2=1/2P1 in bending. |
