Press machine

A press machine for use in progressive processing, comprising:

• upper and lower crankshafts having the same amount of eccentricity and driven in opposite directions with a phase difference of 180 degrees;
• a slide and a bolster rotatably connected to an eccentric part of the upper crankshaft and an eccentric part of the lower crankshafts, respectively;
• a parallel maintaining mechanism configured to maintain a parallelism between the slide and the bolster;
• and
• a clamp mechanism including an upper clamp attached to the slide and a lower clamp attached to the bolster, wherein:
• the slide and the bolster move toward/away from each other and advance/retreat together in a feed direction of the material in accordance with rotational driving of the upper and lower crankshafts, and
• the clamp mechanism clamps the material to be processed when the slide and the bolster move toward each other and unclamps the material forwardly fed while being clamped when the slide and the bolster move away from each other.