Workpiece processing apparatus

A main member for a workpiece processing apparatus configured to use hydraulic pressure to process a workpiece of an object, the main member comprising:

• a base member;
• a punch;
• and
• a piston;
• wherein:
• the base member is formed of a lower member, an upper member placed on the lower member, a die, and a cylinder combined together, and comprising a hydraulic chamber that is fillable with liquid;
• the die and the cylinder have upper surfaces which are exposed from the upper member;
• each of the die and the cylinder has a center hole;
• the hydraulic chamber has a workpiece processing chamber that extends through the center hole of the die and a hydraulic-pressure generation chamber that extends through the center hole of the cylinder;
• the workpiece processing chamber and the hydraulic-pressure generation chamber are coupled together and have openings, respectively;
• the openings open outward from the base member at positions different from each other;
• each of the workpiece processing chamber and the hydraulic-pressure generation chamber extends in an upper-lower direction and opens upward;
• the punch is movable between an initial position which is located above the workpiece processing chamber and a received position at which the punch is partially received in the workpiece processing chamber along the upper-lower direction;
• the piston is partially received in the hydraulic-pressure generation chamber so that the piston is movable in the upper-lower direction and projects upward from the hydraulic-pressure generation chamber;
• the piston receives a pressing force directed downward in a course of movement of the punch from the initial position to the received position;
• and
• the punch and the piston are configured such that, when the punch is moved from the initial position toward the received position under a state where the hydraulic chamber is filled with the liquid and the workpiece is placed on the workpiece processing chamber, the punch is moved downward and presses the workpiece into the workpiece processing chamber, and the piston is moved downward in accordance with the pressing force and increases hydraulic pressure of the liquid.