Patent ID: 8668232

Claim:
A tubular element having a male threading disposed on an end of said tubular element, said male threading comprising: a tapered root surface having a first angle of taper (β) measured between the tapered root surface and a longitudinal axis (aa) of the threading, said tapered root surface being joined tangentially at a first end by a concave curved surface of a constant radius of curvature to a stabbing flank, said tapered root surface being joined at a second end by a convex curved surface of constant radius of curvature to a root groove; said root groove extending from the tapered root surface to a load flank, said root groove including: a first portion comprising a first elliptical surface having a variable radius of curvature, said first elliptical surface being part of an ellipse, and said root groove further including a second portion comprising a second elliptical surface having a variable radius of curvature, said second elliptical surface being part of a second ellipse, said second elliptical surface being joined tangentially at a first end to the first elliptical surface, and said second elliptical surface being joined tangentially at a second end to the load flank.