GB1210242A - Rolling mills - Google Patents

Abstract

1,210,242. Automatic control of rolling mills. DAVY & UNITED ENG. CO. Ltd. March 1, 1968 [March 2, 1967], No.9977/67. Heading G3R. In a rolling mill producing material of constant thickness, thickness errors automatically control the datum of a closed loop control system stabilizing the position of a hydraulic ram between the mill housing and one of the rolls. In Fig.3, a hydraulic ram 7 applies force between a rolling mill housing (not shown) and its rolls 3, 4. Signals from an electrical transducer 8 responsive to ram position are compared at 11 with signals from a potentiometer 14 representing desired position so that any difference is automatically eliminated by causing the difference to adjust a hydraulic valve 12 controlling ram 7. Ram position signals from potentiometer 14 and roll load signals from a load cell 9 are combined to compute signals corresponding to the roll gap which are compared at 16 with signals h<SP>1</SP> representing a desired roll gap so that any difference is automatically eliminated by causing the difference to adjust the position of a motor 15 re-setting potentiometer 14 and hence the position of ram 7. Combined or separate systems control rams at each end of the rolls. In a modification the ram operates in series with a screwdown adjuster which provides a coarse control of roll gap any adjustment of which is arranged to supply a corresponding signal to the roll gap error computer.