| 摘要 |
PURPOSE:To compensate the extent of working pressure according to wear of an upper surface plate, by measuring weight of the upper surface plate by the sensor attached to a piston rod of a cylinder, and regulating fluid pressure to be fed to the cylinder as much as a portion for the wear. CONSTITUTION:When weight of an upper surface plate 11 is measured on the basis of working force acting on a sensor 21, the measured value is inputted into a control circuit, and hereat it is compared with the reference value inputted in advance. And, a control signal corresponding to the difference is outputted to a pressure control valve 25, whereby fluid pressure to be fed to a head chamber 17a of a sub-cylinder 17 is increased. Therefore, the fluid pressure is increased as much as a portion for decrement of the weight W of the upper surface plate 11, thus working pressure is kept constant and compensated. |
