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:
Sep. 11, 1990
Filed:
Jul. 27, 1989
Gerd Pfeiffer, Mulheim, DE;
Erich Quadflieg, Krefeld, DE;
Friedrich Lenze, Ratingen, DE;
Krug, Gerhard, Duisburg, DE;
Josef Siekmeyer, Ratingen, DE;
Mannesmann Aktiengellschaft, Dusseldorf, DE;
Abstract
A drill pipe coupling includes a coupling member (2) having an unthreaded central section (13) with a cylindrical bore (26) therein and an outer shoulder (11,12) on each side thereof. Adjoining the shoulders are respective conical external threads for threading into an internal correspondingly threaded upset head section of a drill pipe formed as a bell elements and including end surfaces (9,10). The drill pipe has an undeformed cylindrical bore (14) connected to the threaded upset head. The drill pipe end surfaces (9,10) sealingly abut the outer shoulders (11,12) of the central section (13) when the pipes are joined together. The drill pipe has an intermediate section (16) adjoining the cylindrical bore (14) and has an inside diameter which decreases in the direction toward the threaded section (5, 6). A cylindrical bore section (18) adjacent the intermediate section (16) extends to the threaded section (5,6) and a rounded transition is located between the cylindrical bore (14) of the undeformed pipe (8) and the intermediate section (16). The drill pipe has an outer shoulder (33) opposite the cylindrical bore section (18) and the outside diameter of the drill pipe in the upset region (23) of the shoulder (33) is identical to or greater than the outside diameter (21) of the undeformed pipe (8) and the length of the region (23) is greater than the length of the intermediate section (16).