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:
Mar. 20, 1984
Filed:
Aug. 21, 1981
Elmo W Geppelt, Tulsa, OK (US);
William H Poore, Tulsa, OK (US);
Delta Limited, Tulsa, OK (US);
Abstract
A method of manufacturing a spiral tube including the steps of positioning an elongated mandrel within a tube, grasping the ends of the tube, forming a point of reduced resistance to torsional force in the wall of the tube, rotating one end of the tube while the other end is held stationary to cause the formation of a spiral groove in the tube, the mandrel defining the minimum interior diameter of the spiral tube so formed, and advancing the means grasping the tube towards each other to compensate for the reduction of length of the tube as the spiral groove therein is formed, and maintaining at least the area of the tube at which the spiral groove is being formed at an elevated temperature.