DRILL PIPE THREADED JOINT Russian patent published in 2014 - IPC F16L15/00 E21B33/38 

FIELD: machine building.

SUBSTANCE: proposed joint comprises union and coupling with triangular taper thread made at their ends on inner and outer surfaces, thread taper equal to 1:8 and pitch equal to 8.467±0.05 mm. Union and coupling thread turn profile features thrust face inclination angle of 20-30 degrees and set face inclination angle of 35-44 degrees. Socket of thread turn profile is composed of ellipse arc described by equation $$\frac{x_2}{a_2}+\frac{y_2}{b_2}=\mathrm{1,}$$ where a is larger axis of ellipse and b is smaller axis. Said larger axis is parallel with thread taper axis while ellipse is tangential to said thrust and set faces of thread turn. Thread turn profile top is cut with respect to thread initial triangle, cut width being equal to 2.3 mm. Said joint comprises inner and outer thrust assemblies, thrust ends of union and coupling being equal in length.

EFFECT: possibility to transmit high torque, fatigue and wear resistance.

2 cl, 3 dwg