DEVICE FOR FORMING PRICKLES ON TUBE AND BAR AND MANUFACTURE OF PRICKLY TUBE AND BAR

摘要

PURPOSE:To manufacture a prickly tube and bar high in height by twisting and inclining rotary axes of rolls through posture holding devices of rolls before and behind annular rotating bodies round pass center line in the same direction to make up a rolling pass. CONSTITUTION:Positions of circular blade shape projections 2A on three or more barrel shape rolls of the same dimension each of which has a circular blade projection 2A and a gear tooth shape projection 2B or 2C or gear tooth shape projections 2B and 2C different in the direction from this circular blade projection on each roll barrel part 1 are arranged in the direction nearly parallel to a pass center line 3. Further, these roll barrel parts 1 are supported by the inside of the circular rotating body on the outside of the circular blade shape projection 2A and the gear tooth shape projections 2B, 2C, kept at the same distance from the pass line 3, the rotating bodies 4 are inclined round the pass line 3 in the same direction by an angle alpha, and at least on the inlet side of the circular blade shape projection 2A, the interval between the barrel parts of the rolls on the inlet side is made smaller than the external diameter of a tubular bar 9 to hold the tubular bar. Rotation and advance are given to the tubular bar 9 relatively to the roll and male screws are formed continuously by three rollers or more on the tubular bar 9 through the circular blade shape projection parts 2A and the gear tooth shape projection parts 2B, 2C of the rolls.