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:
Oct. 30, 1990
Filed:
Dec. 12, 1989
Horst Stinnertz, Willich, DE;
Mannesmann Aktiengesellschaft, Dusseldorf, DE;
Abstract
A method and apparatus for manufacturing seamless metal tubes by the cold pilger process permitting the continuous feeding of fresh cooling and lubricating agent between the mandrel and inner surface of the material being rolled. The apparatus includes a roll stand including tapering calibrated rolls (2) which is reciprocatingly movable in the direction of rolling at a predetermined stroke to define a reduction zone, the rolls (2) rolling with alternating direction of rotation over the material (3) being rolled and a tapering mandrel (1) inside the material for reducing the diameter and wall thickness of the material, wherein at least one of the rolls (2) and the mandrel (1) has a surface discontinuity within the reduction zone for creating a zone of interruption (6) or an annular gap within which no contact occurs between the material to be rolled (3) and the mandrel (1).