Die core shift mechanism - for a double parison extrusion head

摘要

Double parison extrusion die head, for use in a vertical wheel type blow moulding machine having circumferentially arranged moulds with fixed inner mould members and radially movable outer mould members guided to pass over and around the die head and then moved to cooperate with the fixed mould member and clamp about the extruded parison, has movable core members in each extrusion die which are simultaneously moved by a crank arrangement from a rotationally movable member the drive to which is provided at a point equally spaced between the points of attachment of the cranks. Pref. the drive is coupled to the movable member by a keyed shaft passing concentrically through the movable member from one end.