A piston cylinder unit
A screw extruder, for use with or without a calender, has a divided or split extruder head with upper and lower parts or halves hingedly mounted on a collar secured to a flange at the discharge end of the extruder cylinder. Each of the upper and lower extruder halves is movable between an open innoperative position and a closed operative position by a piston cylinder unit acting between a fixture on the respective extruder head part and a fixture on the extruder cylinder. When in closed position, the upper and lower extruder head parts or halves are pressed toward one another by a pair of vertical piston-cylinder units, each having a cylinder with lower end engaging the upper extruder head part and a projection on a piston rod engaging the lower extruder head part. The vertical piston-cylinder units are mounted on pivoted carriers mounted on the collar on the extruder cylinder. The two carriers are interconnected by a horizontal piston-cylinder and are also movable vertically. Operation of the apparatus is effected by an electro-hydraulic control circuit having a processor by which sequential operation of the piston-cylinder units is controlled.
A single screw extruder comprising: an extruder cylinder having a discharge end; a split extruder head mounted on said extruder cylinder discharge end for extruding therethrough; said extruder head having two halves comprising an upper half and a lower half each swingably mounted for actuation to a closed position for extruding therethrough and an open position providing access to the interior of the extruder cylinder for cleaning interiorly of the extruder cylinder; a pair of clamping devices mounted on said extruder head for applying clamping pressure to the two halves respectively in said closed position during said extruding therethrough; said clamping devices comprising a first pair of swingably mounted selectively energized fluid energized piston-cylinder units each having a piston rod releasably coupled to said two halves for applying clamping pressure to the two halves vertically toward each other;
Each said piston-cylinder unit having a respective rotatable vertical-axis pivotal mount on said extruder head selectively rotatable for swinging a corresponding piston-cylinder unit laterally in a respective horizontal direction after uncoupling the individual units from the corresponding extruder head half and swinging each one clear of the extruder head halves for allowing opening of the extruder head and swingably restoring the corresponding unit to a position coupled to said extruder head half in readiness for applying clamping pressure thereto and clamping said halve when the extruder halves are in said closed position.