JPS5624550A - Measuring device for hardness - Google Patents

Abstract

PURPOSE: To enhance measurement accuracy and reliability, by providing a measured object rest on the movable ends of parallel springs supported at their other ends and by calculating the hardness form the quantity of displacement of the movable ends of the springs and a pressure shaft which comes downward into contact with a measured object.

CONSTITUTION: The pressure shaft 1 is fitted with a differential transformer type displacement meter 40 which detects the displacement of the pressure shaft. The rest 11 for a measured object 10, which is provided on the movable ends of the parallel springs 7, 8, is fitted with another differential transformer type diaplacement meter 41 which detects the quantity of siaplacement of the rest 11. The parallel springs 7, 8 are displaced at the same time when the pressure shaft 1 moves down in contact with the surface of the measured object 10. The pressure shaft moves down until the forces of the shaft and the parallel springs are balanced to each other. A calculator 31 processes the analogue outputs of the differential transformer type displacement meters 40, 41 as the length of the move-down of the pressure shaft 1 which is caused after the shaft has come into contact with the measured object 10. The output of the calculctor 31 is changed into hardness by a hardness converter 32. According to this consitution, measurement accuracy and reliability are enhanced.

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