fluid in longitudinal chamber 12 is transmitted over the line 30 the first quick release valve 28 opens and the pressure in the longitudinal chamber 12 decreases due to the connection of conduit 27 to tank 26 the signal over line 30 also is provided to the central control unit 40 by the connecting line 38 central control unit 40 transmits a signal over the line 39 to open the second quick release valve 34 only if the signals from the dynamometers 21 indicate that the loading of the crosshead 7 has fallen below a predetermined value which value is adjustable by the central control unit 40 in this manner when the valve 28 is opened the entire force provided by the force exerting devices 20 is prevented from suddenly acting upon the bearings 8 or if the roller is provided with the rotatable support arrangement of fig3 the crosshead 7 is prevented from abruptly shifting inside the hollow cylinder 6 in the embodiments of fig2 and 3 corresponding parts are denoted with the same reference numbers in the roll arrangement 200 of fig2 the end stops 41 are eliminated and the position of the bottom roller 1 is hydraulically controlled a valve 42 which may be rigidly attached to the force exerting device 20 and consequently to the frame of the machine provides.