CONCRETE DETECTOR AND TOP-END POSITION SENSOR USING CONCRETE DETECTOR

摘要

PURPOSE: To sense the position of the top end of concrete in a labor saving manner. ;CONSTITUTION: Two electrodes 11a, 11a are mounted at the tip end of a vertically movable cable 10 through a winch 12, and a resistance-change measuring circuit 13 with an AC bridge is connected for detecting the change of electric impedance Z between the two electrodes 11a, 11a. A comparison decision circuit 25 capable of outputting a concrete detecting signal S2 when concrete 3 is brought into contact with the electrodes 11a, 11a and voltage (e) between two terminals alters is installed, and an encoder 17 and an electrode-place sensing section 24 are set up so as to be able to obtain the places of the two electrodes 11a, 11a at the time of the output of the signal S2 in a type that the quantity of driving of the winch 12 is detected. A top-end height arithmetic section 23 for arithmetically operating the place of a top end 3a on the basis of the positions of the two electrodes 11a, 11a is fitted previously.;COPYRIGHT: (C)1996,JPO