Patent ID: 6033204
Filing Date: 2000-03-07
Classification: B29C

Abstract:
Apparatus for forming a hollow parison having a flattened annular cross section, comprising:a substantially vertically extending main body;means for feeding a thermoplastic material into the main body;a mandrel placed in the main body, the mandrel extending substantially vertically and having a bottom;a movable piston positioned over the mandrel in the main body for downwardly pressing the thermoplastic material;a core located at the bottom of the mandrel, the core including a first semicircular end member, a second semicircular end member and a first rectangular member, the first and second end members being connected to opposite ends of the first rectangular member to define a first flattened oval shape, the first rectangular member having a longitudinal direction extending substantially horizontally, a second rectangular member having a different shape than the first rectangular member which is interchangeable with the first rectangular member and fit together with the semi-circular end core members to change the width of the parison, both the first and second semicircular end members and the first rectangular member being detachably mounted on the bottom of the mandrel, the first rectangular member being only replaced when the first flattened oval shape is elongated or shrunk in the longitudinal direction of the rectangular member;a die having an inner surface of a second flattened oval shape, the die being placed around the core such that a flattened annular gap is formed between the inner surface of the die and the core and the hollow parison having the flattened annular cross section is extruded through the gap upon downward movement of the piston, the die including movable members to elongate or shrink the second flattened oval shape upon elongation or shrinkage of the first flattened oval shape; andactuator means for moving each of the movable members.