GB1239865A - Hydraulic control apparatus for a rolling mill - Google Patents

Abstract

1,239,865. Rolling. MITSUBISHI JUKOGYO K.K. 3 Sept., 1969 [3 Sept., 1968], No. 43703/69. Heading B3M. An hydraulic control for adjusting the roll gap of a rolling mill comprises a piston 19 which transmits hydraulic pressure along a line 17 to a ram which moves a roll chock and a fluid pressure source connected to the other side of the piston to balance the rolling force transmitted along the line 17 to the piston. The piston is moved by a motor 24 driving a screw 23. A pressure accumulator 35, a reducing valve 37 and a stop valve 36 are provided in the line from the pressure source. In operation the rolls are moved together by opening valves 28 from a pump 31. The control is duplicated for the other end of the roll and the motors 24, 24<SP>1</SP> connected by a clutch 32. The rolls are separated by operating the motors and either the stop valves 36, 36<SP>1</SP> are closed or the reducing valves 37, 37<SP>1</SP> are actuated continuously to maintain the balancing pressure. The motors are actuated by automatic gap control signals to keep the gap constant (not detailed). In an alternative embodiment, Fig. 3, electromechanical reducing valves 38, 38<SP>1</SP> are controlled by pressure transducers 39, 39<SP>1</SP>, 40, 40<SP>1</SP> in the pressure lines to the piston. The hydraulic circuit has a pair of relief valves 26, 26<SP>1</SP> which open under excessive pressure. A further pair of valves 27, 27<SP>1</SP> connect the circuit to exhaust to separate the rolls. The mill is a conventional four-high type, Fig. 1 (not shown), and has a chock balancing device with pistons (15), (16) for the back-up roller chock (7) and the workroll chock (5) respectively.