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:
May. 09, 2000
Filed:
Sep. 02, 1998
Erwin Fuchs, Altmunster, AT;
Weingartner Maschinenbau Gesellschaft m.b.H., Kirchham, AU;
Abstract
A multi-screw extruder consists of contra-rotating screws (20) inserted in a housing, whose flights (1) form intermeshing crests (2) and roots (3), and which have at least two axial sections (21, 22, 23) of flights each differing in number and pitch. To improve the manufacturing conditions, and to achieve uniform wear conditions over the screw length, adjacent axial sections (21, 22, 23) of a screw (20) verge into each other within an axial transition zone (24) free from annular grooves, where all roots (3) extend through the transition zone (24) while making turns (.alpha.) and forming ramifications or combinations (V), and at least one of the crests (2) begins or ends in the transition zone (24).