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:
Jan. 08, 1991
Filed:
Jan. 04, 1990
Applicant:
Inventor:
Horst Rahn, Hassfurt, DE;
Assignee:
UNICOR GmbH Rahn Plastmaschinen, Hassfurt, DE;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
B29C / ; B29C / ;
U.S. Cl.
CPC ...
264508 ; 2642094 ; 2642098 ; 4253261 ; 425393 ; 425396 ; 425812 ;
Abstract
In the production of plastic tubes or pipes which are internally smooth-walled but have peripheral ribs externally, in particular from extrudable, more especially thermoplastic plastic such as PVC, a good filling of the cavities in the moving mold which are provided to form the ribs, is achieved in that said cavities are filled with the molten plastic first at a distance from the separating plane of the moving mold and last in the region of said separating plane.