MEASURING INSTRUMENT FOR BREAKING LOAD ON SURFACE OF BODY TO BE INSPECTED

摘要

PURPOSE:To measure automatically the surface strain of a body to be inspected and the critical load where breaking is caused by detecting the quantity of displacement of a cat whisker in addition to a thrust load on the cat whisker which varies continuously. CONSTITUTION:A DC load voltage LV which rises continuously is applied to the coil 17 of a focus coil FC from a voltage generator 21. The coil FC varies a magnetic field according to the rise in the load voltage LV to place the thrust load which increases gradually upon the cat whisker 12 for detection through a core 14. This load is placed on a sample 3 which contacts the tip 13 of the cat whisker 12 and the sample 3 is strained. The cat whisker 12 is displaced according to the quantity of strain of the sample 13, so the differential transformer DT composed of a core 15 united with the cat whisker and a fixed coil 18 generates a voltage SV corresponding to the quantity of displacement. When a differential circuit 22 detects the time when the output voltage SV varies abruptly,the breaking load is known from the current load voltage LV. Further, the use of a comparator circuit 24 al;lows the load when an optional quantity of strain is generated to be measured automatically.