| 摘要 |
The invention concerns an apparatus that automatically determines the hardness of metals by dynamic shock and is designed for regular testing of hardness in plant laboratories as well as research laboratories. In accordance with this invention, the apparatus for hardness determination by shock consists of a inert element piezoelectric pick-up, which generates a voltage proportional to the elastic recoil energy of the moving element on the tested part upon impact of the moving element with the tested part. The moving element is suspended with springs. An electromagnet that consists of a coil, a core and a second coil, provides the vibration of the moving element. The frequency, in particular the vibration amplitude, remains constant through comparison of the signal provided by a moving-coil transducer in an electronic comparator with a given level and control of a signal generator of the frequency and rate of the supply signal. The voltage signals provided by the piezoelectric pick-up upon impact of spherical penetrator with the part are electronically processed in a measuring unit equipped with a microprocessor. This unit assigns the vibration frequency and feed rate of the part while controlling the rotation speed of the engine that provides the linear feed of the test material.
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