| 摘要 |
<p>The disclosure relates to a novel and improved arrangement of shell pusher for feeding tubular shells into a plug mill. The pusher comprises a ram carriage, which is movably positioned on an elongated carriage track on the upstream side of the plug mill. The ram stroke capacity of the carriage is designed to be relatively minimum, sufficient to advance a shell from a predetermined load position, directly in front of the mill, until the leading edge of the shell is drivingly engaged by the working rolls of the mill. Means in the form of a heavy, elongated rack and pinion arrangement are provided for pre-positioning the ram carriage in advance of each loading operation of a new shell and also in advance of the return of that shell from the downstream side to the upstream side of the mill after each pass. By designing the ram carriage for minimum stroke capacity, the carriage and its ram may be of minimum size and mass, such that the working strokes of the pusher ram may be carried out at a high rate of speed in relation to the size of the equipment and the power requirements of the drive systems therefor. The ram carriage incorporates a hydraulic shock absorber system, which is arranged to controllably decelerate, and dissipate the kinetic energy of, a tubular shell being returned at high speed from the downstream side of the plug mill after a working pass. This enables the shell return operation to be carried out at increased speeds while avoiding excessive distortion of the upstream end of the tube shell, which might otherwise result from high speed impact of the shell against the ram head of the pusher.</p> |
