| 摘要 |
PURPOSE:To accurately detect the destructed state of a specimen while holding an environmental condition, by adding a destruction detection apparatus including a differential transformer for detecting the movement of an iron core to a dynamic fatigue tester and connecting an electric circuit to the output of the differential transformer. CONSTITUTION:Springs 6A, 6B are arranged above and below a cylindrical iron core 3 having a specimen holder 4 suspended therefrom while a primary coil 1 and a secondary coil 2 are attached to the outside of a lower stopper 7B so as to be wound around said stopper 7B to constitute a differential transformer T which is, in turn, attached to a machine frame 10. Further, a load adjusting screw 9 for especially adjusting the spring 6A is mounted and, further, an electric circuit connected to the output of the secondary coil 2 is constituted of a rectifier circuit 12, an amplifying circuit 13 and a comparing circuit 15. The presence and absence of the destruction of a specimen piece 5 is detected by using the change in electromotive force by the displacement of the iron core 3. By this mechanism, the enhancement of testing accuracy can be attained while environmental conditions such as temp., humidity or the concn. of ozone are held.
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