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:
May. 24, 1988
Filed:
Feb. 17, 1987
Dennis H Sansome, West Midlands, GB;
Thiam B Lim, Singapore, SG;
National Research Development Corporation, London, GB;
Abstract
A plug assembly for use in the plug drawing of tubes and like hollow workpieces. In axial succession, from front to rear, the plug comprises three parts in fixed relationship to each other: a foremost first part with a smoothly rounded nose to make smooth and positive contact with the tube at the start of drawing, a parallel-sided middle part which sizes the interior section of the product as drawing proceeds, and a long rearmost part of larger section. During drawing the confronting surfaces of the rear part and the bore of the undrawn tube define a thin cylindrical clearance, relative movement between the walls of which exercises a hydrodynamic action upon lubricant lying within the tube rearward of the plug, forcing that lubricant forward through the clearance into the region where tube and plug first make contact. Alternative plug shapes for the third part of the plug are proposed, including parallel-sided, stepped and sloping.