Knockout device for punching a work plate in a press-machine

A knockout device for punching a work plate in a press-machine, including a plurality of punches fixed to the underside of a base plate through a punch fixation plate and a punch support plate so as to protrude downwardly, which device comprising, in combination:

• (a) a work fixation plate fitted to the punches vertically slidably;
• (b) a cylinder chamber of a hydraulic knockout cylinder formed in an upper portion of the base plate;
• (c) an actuation-plate guide hole formed in an lower portion of the base plate;
• (d) a piston provided vertically slidbly in the cylinder chamber;
• (e) a knockout actuation-plate provided vertically slidably in the actuation-plate guide hole;
• (f) a plurality of knockout pins passed vertically slidably through both the punch fixation plate and the punch support plate;
• (g) said work fixation plate being adapted to be actuated downwardly by the downward movement of the piston through the knockout actuation-plate and the knockout pins so as to knock out downwardly the punched work plate frictionally engaged to the punches;
• (h) said cylinder chamber of the hydraulic knockout cylinder being disposed at an eccentric postion offset toward the periphery of the actuation-plate guide hole relative to the center thereof;
• (i) a linear guide hole formed upwardly from the central portion of an upper plane of the actuation-plate guide hole in communication thereto;
• (j) a linear guide boss formed so as to protrude upwardly from a central portion of the knockout actuation-plate;
• and
• (k) said linear guide boss being fitted vertically slidably into the linear guide hole so as to be guided thereby.