PURPOSE: To improve the productivity without receiving the effect of the kind of a wire rod, wire diameter and required hardness by adjusting continuously the tensile strength and the elongation of the wire rod.
CONSTITUTION: The wire rod 1 taken up on taking-up capstan 4 at a prescribed speed is set over plural rolls 9 fixed to a first roll fixing part 10 and a second roll fixing part 11 arranged in a bending roll part 3 at a prescribed interval to be subjected to bending work. At the time of working, the outer diameters of the wire rod 1 at the inlet and the outlet of the bending roll part 3 are measured with outer diameter measuring instruments 5a, 5b. Based on the measured outer diameter, a contraction of area of the wire rod 1 is calculated by a computing element 6, and based on the contraction of area, the interval between the first roll fixing part 10 and the second roll fixing part 11 is adjusted through a driving motor 8 controlled by a motor control part 7 to adjust the bending angle of the wire rod 1.
NAKAJIMA KAZUYUKI
MAZAKI YOSHIHARU
