DETECTOR FOR LENGTHWISE CRACKS ON CONVEYOR BELT

PURPOSE:To detect lengthwise cracks on a belt with high precision, by embedding an inner magnetic sensor and an inner magnetic generator into a conveyor belt laterally forming a pair, and arranging an outer magnetic generator and an outer magnetic sensor at the outer side of the conveyor belt. CONSTITUTION:A plurality of inner magnetic sensors 3, inner magnetic generators 4 are respectively embedded at left and right side edge portions of a conveyor belt 1 equidistantly in a lengthwise direction, where each of the magnetic sensor 3 and the magnetic generator 4 is constructured by arranging a winding around a pot-core of high magnetic permeability and both 3, 4 are electrically connected to each other by a conductive member 5. On the other hand, one set of an outer magnetic generator 8 and an outer magnetic sensor 9 is arranged at the outer portion of the conveyor belt 1 so that the generator 8 is opposed to the inner sensor 3 and the sensor 9 is opposed to the inner generator 4. In addition, magnetic field generated from the outer magnetic generator 8 is detected by the inner magnetic sensor 3, and magnetic filed is generated from the inner magnetic generator 4 driven by an output signal of the inner magnetic sensor 3, while the outer magnetic sensor 9, detects said magnetic filed and a discrimination circuit 13 detects any crack on the conveyor belt 1 by the presence of an output from the sensor 9.