MATERIAL SUPPORTING DEVICE OF PRESS BRAKE

PURPOSE:To follow up rotation of a plate with high accuracy by detecting the angle of rotation of the second rotating mechanism that rotates in conformity to the rotation of the plate and controlling the first rotating mechanism according to the difference of angle of rotation between the second mechanism and the first rotating mechanism. CONSTITUTION:A plate 1 is bent by the upper die 4 of a press brake. The plate 1 starts rotation around the shoulder 9 of a lower die 3, and inputs the change of rotation pulse of the second shaft encoder 20 to a controlling device. The controlling device judges starting of rotation of the plate 1 by the change of inputted pulse, and drives a motor 15 at a speed according to a command pulse programmed beforehand. Further, it rotates a supporting member 11 concentrically with rotation of the plate 1 through the first rotating mechanism 12. The controlling device calculates the change of angle of rotation of the plate 1 and generates a command pulse proportional to the rotational position and the speed of the plate 1. The angle of rotation of a driving shaft 13 is detected by the first shaft encoder and the rotational pulse is inputted to the controlling device. Here, the motor 15 is driven in proportion to the difference between rotation pulses of the command pulse and an encoder.