APPARATUS FOR MEASURING THE DRAFT OF A ROLLED STEEL

摘要

An apparatus for finding the draft of a rolled steel by measuring the moving speed of magnetic marks attached by magnetization to the strips on the input and output sides of a rolling mill, wherein the rise of a signal is used as a timing for detecting the magnetic mark on the input side, the signal being obtained by the logical product of a detecting signal of the input side and a gate pulse that opens with a magnetic mark detecting signal of the output side and that closes after an optimum period of time has passed, and wherein the comparator level of a detector is automatically changed depending upon the magnitude of the magnetic mark that is stored, in order to improve the S/N of magnetic mark signals of the input side and to reduce the erroneous detection as much as possible.