DEVICE FOR CONTROLLING THE RAISING AND LOWERING OF HOLD-DOWN ROLLERS OF UNWINDERS OF HOT ROLLED STRIP

摘要

The device serves to control the desired lifting and pressure-containing movements of strip pressure rolls for the reels which serve to store hot rolled strip. These reels have a rotating mandrel. The pressure rolls are actuated by piston and cylinder units for positioning the rolls electro-hydraulically in conformity with signals which indicate the relative position of the leading strip edge which rotates with the mandrel. The positioning of the roll, by the lifting and pressure-contacting movements, is effectd by position control with subordinated pressure control in a closed-circuit position control loop and a closed-circuit pressure control loop, by input of a setpoint position value which corresponds to the respectively prevailing pressure-contacting and lifting position of the pressure rolls, and by establishment of limited setpoint pressure values for both functions or directions of movement.