THREE-ROLL STAND OF SCREW ROLLING MILL Russian patent published in 2001 - IPC

FIELD: rolled tube production, namely improved three-roll stand of mill for screw rolling. SUBSTANCE: three-roll stand includes housing with cover, three rotary drums with working rolls, screwdown mechanisms for lengthwise motion of rotary drums, mechanisms for rotating drums by feed angle provided with screw stoppers and hydraulic cylinders, additional mechanisms for lengthwise motion of drums with rolling rolls having limiting stops. Rolling of leading end portion of tube is realized at drawn apart rolling rolls when drum with rolling roll is turned by small feed angle and it is pressed by means of hydraulic cylinder o screw stopper. When tube end achieves necking of deformation zone, rolls are drawn together by necessary value. Simultaneously feed angle is increased, pressure is supplied to one hydraulic cylinder, other hydraulic cylinder is joined with drainage and drum is pressed to screw stop. Stand allows to eliminate manual operations at tuning roll gap and to lower time period for stand repairing. EFFECT: improved design of stand providing enhanced efficiency due to reduced idling periods and automatic control of stand. 6 dwg