公开(公告)号：US12044077B2

公开(公告)日：2024-07-23

申请号：US17909909

申请日：2021-03-10

申请人： SANDVIK MINING AND CONSTRUCTION TOOLS AB

发明人： Tomas Jansson ,  Andreas Norman ,  Anders Nordberg

IPC分类号： E21B17/042

CPC分类号： E21B17/042

摘要： A drill string including an elongate hollow main length section and a male spigot portion provided at the second end and having an externally threaded section and a non-threaded shank positioned axially intermediate the main length section and the threaded section. The shank includes a transition section positioned adjacent the main length section or a radially projecting shoulder at the second end. The transition section has an outside diameter that increases in a direction from the male spigot portion to the main length section or the shoulder. The cross-sectional shape profile of the outer surface of the transition section in the plane of the longitudinal axis has a segment of an ellipse having semi-major axis (a) and a semi-minor axis (b), wherein the ratio of the semi-major to semi-minor axes (a:b) is within the range 2b