JPS54156561A - Steel material position detecting method in compression joint parts of steel-cored stranded cables - Google Patents

Abstract

PURPOSE: To eliminate the need for sensitiveity adjustment and zero point adjustmet of magnetic detectors and make detection with high sensitivity by comparing the signal immediate befor the magnetic detector as a reference signal with the signal immediate thereafter in the moving process of said detector and detecting the magnetic pole having maximum magnetic force, i.e., the end part of a steel material.

CONSTITUTION: A magnetic detector 3 composed of a Hall effect element or the like is moved along a compression-joint part 2 to electrically detect the magnetism from the steel core 1a in a socket 2c through a non-magnetic jumper socket 2c. The output signal of the detector 3 is integrated in a peak value holding circuit 5 through a polarity changeover circuit 4 to maintain the maximum signal thereof. This signal is used as a reference signal. A comparator 6 compares the output signal b from the circuit 4 and the reference signal b' from the holding circuit 5 and generates an output signal c when these become b<b'. Hence, it is when the detector 3 positions at the end part of the steel core 1a in the compression-joint part 2 that the comparator 6 generates the output signal c. The output signal c is differentiated in a differentiating circuit 7 which in turn generates the pulse signal d. This positive pulse signal e is sent to a display device 6 to display the steel core end part position.

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