Apparatus for selectively positioning rolls in a calender roll stack

Abstract

A hydraulic adjustment motor containing a piston-and-cylinder unit is provided at the roll surface of a roll to be moved to position the roll surface relative to another roll surface of a further roll. Each adjustment motor is arranged between the related roll surface to be moved and its related roll stand. A regulation device is arranged between a pressure source, the pressure chamber of the adjustment motor and a hydraulic medium vessel. This regulation device regulates impingement of the pressure chamber with different pressures up to the maximum pressure of the pressure source and regulates the outflow of a selected volume of the hydraulic medium out of the pressure chamber, correlated to the desired lowering of each roll surface, during lowering of the roll surface and for maintaining a residual volume of the hydraulic medium. Consequently, there is provided a defined relative position between the roll surfaces. This apparatus allows raising, relieving, lowering or holding of the work surfaces of the rolls in desired positions. The apparatus is suitable for rapidly moving apart individual rolls, such as intermediate rolls of the roll stack. By setting an appropriately reduced pressure in the pressure chamber the apparatus can take-up the weights to be relieved, for instance the overhanging or cantilever weights or marginal loads at the individual roll surfaces and to counteract the same.