US Patent 9004544 Threaded joint for tubes, pipes and the like

A threaded joint comprises a coupling, a first pin, and a second pin, wherein the thread of the first pin has a pitch different from the pitch of the thread of the second pin. The extremities of the pins have slanted contact surfaces of complementary shape that make mutual contact after make-up of the joint. The slanted common plane of contact of both pins has an angle to the plane perpendicular to the longitudinal axis of the joint which is greater than 0°. In an alternative embodiment the contact surfaces of the pins are split into two staggered planes and comprise a seal in-between.