METHOD OF THREADING PRECUTT THREAD Russian patent published in 2012 - IPC B21H3/04 B24B39/04 

FIELD: process engineering.

SUBSTANCE: invention relates to threading of precutt thread. Billet is revolved. Threading device is fed in lengthwise direction in step equal to thread pitch and pressed against billet to allow free rotation by friction forces. Said threading device comprises body, holders with deforming elements free running therein, and power element. Deforming elements are made up of two threading rolls in the form of truncated cone with length not smaller than thread profile height. Holders are fitted on two-arm lever ball ends. Threading rollers are mounted at the angle of that of thread profile side inclination. Power element is secured at lever center and made up of torsion box to be twisted relative to axis perpendicular to biller lengthwise axis. Threading rollers work on thread profile both sides with deforming contact force created by power element.

EFFECT: expanded performances, higher efficiency, lounger life and higher wear resistance.

5 dwg