| 摘要 |
PROBLEM TO BE SOLVED: To provide an inspection device capable of inspecting precisely and surely a welding defect, such as a crack of a welded zone, slag inclusion or the like by hammering. SOLUTION: An external force, applied to a weld zone 1 by a hammer 2 for generating a hammering sound is detected by an exciting force sensor 11, and the ratio thereof to an external force reference value is determined by a ratio computing unit 15. The hammering sound generated on the weld zone 1 is detected by a microphone 3, and separated into time series signals in each frequency zone by an analog BPF 5, and rectified and instantaneous maximum values in each frequency zone are extracted by a peak hold 7. The maximum values are corrected by the ratio calculated by the ratio computing unit 15, and compared with a sound pressure reference value set up beforehand by a comparator 9. When the result is out of the prescribed relation, comparison result signal are issued, and if the number of the comparison result signals is three or more, an alarm unit 18 gives the alarm. As the maximum values of the time series signals in each of the plural frequency zones are extracted and compared, the state of looseness can be inspected accurately. |
