Torque transmission in screwed drill pipe coupling

摘要

An outwardly facing socket (4) is affixed to the top end of one drill pipe (2) and holds a nipple (6) with an inward projection sepg. the one pipe from the bottom of the next pipe above. Between an inclined outer surface of the nipple and an inclined inner surface of the socket is a split annular ring (11) compressed by a flange-topped screw (7) inserted into the socket to pull the two pipes together. To transmit torque between the two pipes, these two inclined surfaces are made eccentric to the pipes' longitudinal axes (3). The outer surfaces of nipple and socket may be ellipsoid in a transverse plane, with the screw engaging sets of grooves and projections formed on diametrally opposite sides. Esp. for drilling with indirect fluid feed. Rotary movement is transmitted more simply and effectively than with known bulky joints involving large removable bolts.