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:
Apr. 04, 1989
Filed:
Oct. 07, 1987
Charles E Maillefer, 1164 Buchillon, CH;
Other;
Abstract
The inside surface of an extrusion cylinder (1) is divided into an upper surface (2) and a lower surface (3), each in the shape of an arc of a cylinder. The two surfaces intersect so that two screw sections (8, 9), each provided with a helical thread (12, 13), mesh with each other. The two threads are complementary in that the width of one thread (12 ) gradually increases from an entry opening (6) downstream, while the width of the other thread (13) decreases gradually from the upstream end toward the exit opening (7). Owing to separations between the free spaces, the material poured into the extruder through the entry opening is forced to pass once into a working zone in order to reach an exit chamber where the pressure is less than in the entry chamber.