JPS5756113A - Screw down device for pinch roll of rod mill - Google Patents

Abstract

PURPOSE: To prevent a coil break of a rod in a coil forming pipe held in a coiler, and to form a coil in a prescribed outer diameter, by determining a pinching point of a pinch roll correspondingly to the kind of the rod to be processed, according to a signal of a rod size detector installed on the run-out side of a rod mill.

CONSTITUTION: A measuring signal for the outer diameter of a rod obtained by a rod size detector 12 is compared with a preset signal optionally set in a rod size presetter 13 by a pinch roll's reduction discrimination circuit 14; and then, the outer diameter of the rod is controlled to the preset size. The distance between the roll 9 and the detector 12 is known so that a time required in traveling this distance is obtained from a signal sent from a speed detector 3. Accordingly, if the diameter of the rod is large, a prescribed time after the rod passes over the detector 12 at the rear end, a pinch roll's reduction controlling circuit 6 permits the roll 9 to pinch the rod through a pinch roll reducing coil 7 and a pinch roll reducing cylinder 8. If the diameter of the rod is middle size, after the tip of the rod arrives at the detector 12, the signal of the detector 12 permits the roll 9 to pinch the rod; and after a prescribed time, the circuit 6 permits the roll 9 to cease the pinching. The pinching for the tail end is controlled similarly to the said procedure. If the rod diameter is thinner, the rod is pinched similarly to the case of the middle diameter rod, and the pinching is continued until the rod passes over a rod detector 15.

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