Patent ID: 6463643
Filing Date: 2002-10-15
Classification: B29C,Y10T

Abstract:
Apparatus for withdrawing two screws from the barrel of a twin screw extruder in conveying direction of the screw extruder, with each of the screws defining a longitudinal axis and terminating in a screw cap, said apparatus comprising:a pair of grippers, each of the grippers interacting with a corresponding one of the screws, whereby the grippers and the screws are placed into one-to-one correspondence, wherein the grippers are arranged in side-by-side parallel disposition at a distance, which corresponds to a distance of the two screws, and braced together by a connecting member for retaining their alignment, wherein each gripper has a free end for attachment of a pull mechanism and a grabbing end for interaction with an undercut of the screw cap, wherein each gripper is formed at the grabbing end with a plurality of clamping segments which are radially resilient with respect to the longitudinal axis so as to be elastically bendable inwards and/or outwards, and which form parts of a hollow cylinder in longitudinal direction thereof, with the hollow cylinder having an inner diameter, which substantially corresponds to an outer diameter of the screw cap, and an outer diameter which is smaller than a diameter of a bore of the barrel, wherein each of the clamping segments terminates in a beaded end which extends radially into the hollow cylinder for formation of a gripping claw, said beaded end having a wall thickness which is smaller than a difference between a radius of the barrel bore and an outer radius of the screw cap, and, in longitudinal direction of the gripper, a length which is smaller than a width of the undercut of the screw cap in longitudinal direction of the screw.