| 摘要 |
PURPOSE:To perform high-precise shearing of a hoop steel in an acceleration reduction part at a line speed, by a method wherein, at a point of time when a shear starts shearing driving motion during acceleration and reduction of a line speed, the feed speed of a roll is specified or coincided with the driving speed of the shear. CONSTITUTION:When transfer of a hoop steel 1 is started, a signal from a pulse generator 13 is outputted to a shearing length computing control device 17. When the hoop steel 1 is fed approximately to a given length, based on a speed set value for a feed roll and a signal from a tachogenerator 12, fixed command control is effected on a line speed by means of a control device 18. Simultaneously therewith, based on a speed instruction value for a shear and a detecting signal for a rotation speed from a rocking shear 6, and a driving signal is outputted to a driving circuit 19. Responding to the driving signal, driving of a driving motor 14 is started to start movement of the rocking shear 6, and a rotation speed is controlled to a value coincided with a line speed until the rocking shear is moved to a shearing position. When the rocking shearing 6 is moved to the shearing position, the hoop steel 1 is sheared. This constitution enables high-precise shearing of the hoop steel.
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