公开(公告)号：US3822952A

公开(公告)日：1974-07-09

申请号：US27287372

申请日：1972-07-18

Applicant: SANDVIK AB

Inventor： JOHANSSON E ,  LUMEN K

IPC: E21B17/042 ,  E21B17/02

CPC classification number: E21B17/0426 ,  Y10T403/5746 ,  Y10T403/68

Abstract: A drill rod coupling assembly in which each of two rods has at least two spaced sets of threads, the outer of which are coupled by a sleeve so that percussive force is transmitted through the abutting ends of the rods The threads at the end of each rod are designed for surface to surface contact with matching surfaces on a stop in the sleeve. Whenever the outer set of threads is worn or broken they may be cut off and a new end similar to the original end is provided and may be coupled by the sleeve.