Patent GB-924870-A (GB)
Title: Workpiece position control apparatus
IPC: B25J9/16
Filed: 1960-06-01
Abstract: 924,870. Programmed electric control systems for rolling mills. WESTINGHOUSE ELECTRIC CORPORATION. June 1, 1960 [June 5, 1959], No. 19382/60. Class 38 (6). [Also in Group XXII] The manipulators of a rolling mill move the billet from an initial position to one side so that it can be turned and then move it to a new position. The initial and final positions are recorded in digital code on a punched card; the intermediate positions are computed: As the billet leaves the mill stand, Fig. 1 (not shown), detectors 90, 92, Fig. 3, cause a timer 58 to initiate the sequence by passing the initial position signals Ro and Lo from the card reader 50 to right-hand and left-hand stores 54, 56 and thence by gates 62, 64 to control circuits 22, 26. Each of these consists of a digital error detector 100, Fig. 10, which compares the signal from its gate, e.g. 62, with the output of a position digitizer 104 driven by a motor 24 which also drives the manipulator, e.g. 18. The error signal, after conversion from digital to analogue form at 102, causes the motor 24 to run to correct the error. A gate 106 detects the absence of error and passes a signal to the timer 58 to initiate the next phase of the sequence. Timer 58 also controls a relay 200 to prevent motor 24 running at the wrong stage in the sequence. Thus both manipulators move to their initial positions R and Lo. The card reader 50 is then said to pass a signal to a storage device 52, which, together with the timer 58 can cause gates 60 (one for each digit of the signal) to control gates 62 (again there is provided one per digit) so as to give a prearranged code output R1. This moves the right-hand manipulator to the right away from the billet to a fixed billet turning position R1. Meanwhile, the two initial position signals R0 and L0 have been supplied from the stores 54, 56 to a circuit 68 which subtracts one from the other to provide a signal proportional to the initial distance between the manipulators, i.e. the billet width. By subtracting this width signal from the new righthand manipulator signal R1 at 66, a signal L1 is provided to cause the left-hand manipulator to also move to the right until the billet is again gripped. This signal L1 from 66 is also stored at 67. The final position signals R F , LF are now read at 50 and stored at 54, 56. These two signals are subtracted one from the other at 68 to provide a signal proportional to the height of the billet, i.e. the width when turned on its side. The new width signal is subtracted at 66 from the left-hand manipulator signal L1 which has been stored at 67 to provide a signal L2, the necessary opening of the manipulator to allow the billet to turn, and the left-hand manipulator moves accordingly. The same signal L1 is also applied to the right-hand manipulator by gate 62 so that this manipulator follows as the billet rolls away due to the action of lifting fingers carried on the manipulator. This move is said to commence when the lefthand manipulator is 6 inches away from L2 because of a " suitable device ". The timer 58 finally causes the signals R F , L F  to be passed from the stores 54, 56 to the actuators and the manipulators move to their final positions.