| 摘要 |
1,149,236. Rolling. DAVY & UNITED ENG. CO. Ltd. 26 April, 1966 [3 May, 1965], No. 18586/65. Heading B3M. [Also in Division G3] A prestressed rolling mill includes a mechanism for automatically controlling the prestressing force, to maintain the thickness of a rolled product constant, a mechanical screwdown for the mill being automatically operated if the prestressing force departs from a given range. Hydraulic prestressing jacks 27, 28 are positioned between the backing chocks 14, 15 of backing rolls 15, 16, work rolls 25, 26 being positioned within chocks 23, 24 located within the chocks 14, 15. Further jacks 31-33 act between the various chocks, all the jacks being supplied with oil from a pump 60, Fig. 1, via appropriate valves 63A and 63 and 71. For setting up the mill the prestressing force applied to the jacks 27, 28 is kept constant while the screws 20 are automatically adjusted to provide a constant workpiece gauge, while for running the mill, the screws remain in position (except when the prestressing force departs from its given range) and the gauge control is effected by varying the prestressing force. During setting up, switch 76 is charged to " set up " and the valve 71 is controlled by a differencing circuit 75, the pressure in rams 27, 28 being maintained at a value set manually at 77. Variations in this pressure as measured by a load cell 30 cause a difference signal to appear at amplifier 78 to modify the pressure. A gauge error signal is simultaneously fed from amplifier 81 to a gate unit (85), Fig. 3, the signal causing operation of contactors 36 to vary the screwdown, if the gauge error exceeds a manually adjusted gate width value set at 86. When a meter 99 indicates that the mill is running on-gauge the switches 76 and 84 are changed over so that a gauge error signal is fed to amplifier 78 to control the valve 71. The gauge error signal is compounded of signals from load cells 30 and 21, from synchros 37, 40 sensing the screw position, and from a manually set device 96 indicating the desired gauge. A further signal from a thickness gauge 103 or 104 is fed through a monitor integrator 107 to cause a long term adjustment of amplifier 81 for ongauge rolling. A potentiometer 46 is adjusted initially so that when the work rolls just touch each other the gauge error signal is zero. |
