The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 10, 1990
Filed:
May. 01, 1989
Michael Hirschberger, Sylvania, OH (US);
Hoover Universal, Inc., Ann Arbor, MI (US);
Abstract
Dual parison extrusion head for multi-layer extrusion blow molding in which a die body surrounds two parallel spaced mandrels to form two cylindrical passages from which parisons are extruded. A series of resin supply conduits are provided for directing each resin to both passages. The series of conduits are axially spaced in the extrusion head to direct a plurality of plastic resins to each of the passages to form a multi-layer parison. The resin supply conduits are symmetrical about a vertical plane transversely bisecting the extrusion head between the two passages to produce flow and thermal symmetry in the resin to balance the resin flow to both passages. The resin supply conduits are configured so as to produce the dual parisons with the resin weld line of the multiple resin layers being located on the blow mold parting line. The resin conduits are positioned to minimize the center distance between parisons to reduce the size of the extrusion head. This is accomplished in part by feeding the resin downwardly before the resin flows into the cylindrical passages to form the parisons.