Patent ID: 6164175
Filing Date: 2000-12-26
Classification: B23D,Y10T

Abstract:
A method of operating a rotating starting shear operated in a start-stop operation on rolling stock travelling at different speeds in a rolling mill, the starting shear having shear knives and a gear unit coupled to a drive motor, wherein the shear is accelerated from a position of rest to approximately the speed of the rolling stock and, after a cut has been carried out, the shear is stopped again, a gear mechanism being arranged between the gear unit and the drive motor of the shear, wherein the gear mechanisms is connected to the gear unit of the shear through a torsion-proof first coupling and the gear mechanism is connected to the drive motor through a torsion-proof second coupling, the method comprising carrying out the following steps:(a) starting the shear with a low drive torque over a short period of time required for eliminating play of the gear unit and the couplings, subsequently(b) carrying out a constant acceleration of the shear with maximum acceleration torque to a desired speed of the shear independently of rolling stock speeds and rolling stock cross-sections, shifting a starting point of the acceleration of the shear in dependence on the rolling stock speed and the rolling stock cross-section, wherein the (desired speed of the shear is selected greater than the speed of the rolling stock,(c) beginning the cut shortly prior to reaching the desired speed of the shear at a point in time at which the shear speed is already greater than the speed of the rolling stock; and(d) automatically monitoring a circumferential speed of the shear knives during the cut in order to maintain an optimum lead of the shear.