Drill pipe coupling

US4955644A · kind A · utility

Assignee

• Mannesmann AG · DE

Inventors

• Gerd Pfeiffer · Poughquag, US
• Erich Quadflieg · Krefeld, DE
• Friedrich Lenze · Ratingen, DE

Key dates

• Filing date: Jul 27, 1989
• Grant date: Sep 11, 1990
• Expiry date: Jul 27, 2009

Classification

• Technology area (CPC E): Fixed Constructions
• CPC primary: E21B17/042
• WIPO field: Mechanical elements
• WIPO sector: Mechanical engineering

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 reg…