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. 22, 2002
Filed:
Sep. 29, 2000
Douglas V. Snapp, Singapore, SG;
Frank J. Carlin, Hempstead, TX (US);
Grant Prideco, L.P., The Woodlands, TX (US);
Abstract
The roots of the box threads in a drill collar or heavyweight drill pipe are configured to reduce the connection stresses encountered during drilling and makeup of the connection. The thread root design in the box reduces fatigue damage caused by makeup torque and cyclic stressing of the engaged drill string connection as it is rotated around curved sections of the well bore. A conventional V-type thread form in the box is provided with an enlarged root radius having its center point offset from the centerline of the opposing thread flanks. The load flank of the thread tangentially engages the arc of the root. The stab flank of the thread is intersected by the enlarged root radius extending to a flat intersecting surface that may extend as far up as the thread pitch diameter.