Procedure and equipment for the manufacture of pipes with external and internal diameters varying in stages

US4445354A · kind A · utility

Inventors

• Gerd Pfeiffer · Poughquag, US
• Horst Stinnertz · Willich, DE
• Fritz Zeunert · Usedom, DE

Key dates

• Filing date: Jul 22, 1982
• Grant date: May 1, 1984
• Expiry date: Jul 22, 2002

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B21B21/02
• WIPO field: Machine tools
• WIPO sector: Mechanical engineering

Abstract

The present invention relates to a cold pilger rolling mill and a method and means for manufacturing tubes with externally and/or internally thickened portions by reducing the tubes over a mandrel by means of grooved rolls which are mounted in a reciprocating roll stand. The invention provides several different varying diameter grooves on the rolls, which grooves can be brought into play one after the other by rotation of the rolls through an adjustment of the toothed racks on which the rolls are mounted. Consequently, at least one groove is provided for the rolling out of the required cross-section of most of the tube and a second groove is provided for the rolling of a thickened portion of the tube. It is essential that a smoothing zone is associated with each groove, and a zone for rotating and advancing the tube is associated with at least one of the grooves.