| 摘要 |
Joint for drill strings and thin-walled tube intended for drilling to explore for minerals, with a longitudinal central axis, comprises a first female part (B) and a second male part (P) which can be connected to the female section. The two parts each have a first annular section (13, 11) with a shoulder at the end of the annular section (13A, 11A), a second annular section (14, 12) with a shoulder at the base (14A, 12A) axially opposed to the end shoulder and a conical thread placed between the two sections so it acts with the thread on the other part and allows their coupling by screwing the two parts together. Each shoulder is inclined and each male and female part has a foot (34, 35), a crest (32, 33), a pressure flank (22, 23), a disengaging flank (19, 18) and the first and second opposite ends of a helix. Each pressure flank has an inclined helical surface which can be butted against the inclined surface of the other pressure flank, so each shoulder is inclined at an angle of between 5 and 10 degrees approx. to the perpendicular to the central axis. The foot and depth of the two threads are constant between the first and second parts and each foot and crest has a conical surface inclined at between 0.75 and 1.6 deg. to the central axis. The negative angles of the flanks are between 7.5 and 15 deg. to the perpendicular to the central axis. |
