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. 31, 2012
Filed:
Oct. 18, 2008
Hubert Kossner, Schwanfeld, DE;
Hubert Kossner, Schwanfeld, DE;
Unicor GmbH, , DE;
Abstract
A method and an apparatus for producing an endless double-walled pipe having corrugated pipe sections and sleeve pipe sections are described. The production is effected by extrusion of an outer tube (Sa), forming the outer pipe of the double-walled pipe, and of an inner tube (Si), forming the inner tube of the double-walled pipe, in a molding passage () having sections with a corrugated molding surface and a smooth cylindrical sleeve molding surface. To shape the sleeve section, the outer tube is extruded into the sleeve molding surface and is brought into contact with the sleeve molding surface. The inner tube (Si) is then extruded into the outer tube (Sa), already in contact over the entire axial length of the sleeve molding surface, and is brought in the process into contact with the inner side of said outer tube (Sa) that is in contact.