| 摘要 |
PURPOSE:To provide a titled sensor which eliminates mutual electromagnetical interferences and enables the detection of a groove with high accuracy by the constitution wherein ACs having respectively different frequencies are applied to two sets of detecting coils having the centerlines intersected with each other on the side of the work and the difference between the detected outputs is determined. CONSTITUTION:Two sets of detecting coils 11, 21 which are juxtaposed on the face WS of the work W to be welded and the plane at a right angle to the groove line WL for butt welding are inclined to intersect the respective centerlines with each other on the side of the work W, whereby a sensor S is constituted. Electromagnetic coils 1, 2 provided in series with coils 12, 22 for compensating temp. in the stage of high temp. are formed respectively to the coils 11, 21. The external terminals U1, V1, W1, U2, V2, W2 of the sensor S are connected to AC bridges B1, B2 consisting of AC power source 3, 4 differing in frequencies and impedances 13, 14, 23, 24. The coils 11, 21 are excited with such AC power source device AC and the detected outputs thereof are inputted respectively with amplifiers 5, 6, filter circuits 7, 8 and rectifier circuits 9, 10 to a differential amplifier 30. The position of the groove line WL with respect to the sensor S is detected from the difference between said outputs. |
