Patent ID: 8262139

Claim:
Rock-drilling equipment comprising a female part and a male part, which are connectable with each other via a threaded joint in which an internal trapezoidal thread in the female part and an external trapezoidal thread on the male part are included, each one of the threads being in the form of a helix thread ridge, which is delimited by a top and two flanks, a groove, having a bottom, running between two tops, and which thread ridge extends a plurality of turns between front and rear ends of the rock-drilling equipment, the individual thread top touching an imaginary cylinder or cone concentric with a centre axis, wherein the groove bottom of at least one of the threads has a concave and partially circular cross-section shape along at least a part of the extension of the groove, and transforms into the flanks via concave radius transitions, the radii of which decrease in the direction axially from one end of the thread ridge toward the other one, at the same time as the radius of the groove bottom increases in the same direction.