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:
Sep. 24, 2002
Filed:
Jul. 11, 2000
Robert A. Barr, Virginia Beach, VA (US);
Other;
Abstract
An extruder screw mechanism has a barrel that is heated by heating coils, an internal screw, and a cylindrical melt sleeve having a plurality of circumferentially spaced, axially extending, radial slots there through located between the external barrel and the internal screw. Another embodiment of the extruder has a barrel and an internal screw, with the internal screw having either a single central axial bore or a plurality of internal axial bores. The internal screw is provided with a plurality of external threads, with the threads each having a curved starting portion with a helix angle that has a finite value and gradually increases along an initial portion of the screw until the threads are substantially linear and parallel to the axis of the screw along the melting portion of the screw; a related embodiment has threadless portion separating the linear threads from the curved upstream threads. Circumferentially spaced, axially extending, radial slots extend from the outer surface of the screw along the melt section portion of the screw radially inwardly to an associated axial bore for removing melted polymer as it forms between solid polymer and a heated surface.