| 摘要 |
PURPOSE:To simplify a mechanism of applying optimum pressing force for drawing and setting upon an upper roll by using double cylinders which can apply two different pressures upon an upper roll pressing cylinder. CONSTITUTION:When a hydraulic pressure P1 is exerted upon the rod side of a main piston 3 having an effective area A1, the pressing force of a roll 8 is F=A1.P1, by which a powerful pressing force is acted upon a dummy bar 9 and the dummy bar is guided in a drawing direction. If a hydraulic pressure P2 is exerted upon a free piston 4 having an effective area B1 when the bar 9 is going to shift to an ingot 10, the piston 4 forces a clevis 5 upward by contacting therewith. When the ingot 10 contacts with the roll 8, the clevis 5 is forced upward by as much as the level difference between the bar 9 and the ingot 10, but the pressing force F of the roll 8 decreases to F=A1.F1-B1.P2. In this time, deformation arises in the ingot 10 and when the same exceeds an ordinary thickness, the clevis 5 is pulled upward above the stroke of the free piston 4 and a spacing S is created between the piston 4 and the clevis 5. Therefore the roll pressing force F is F=A1.P1. Under which the ingot 10 is leveled. |
