SU932370A1 - Dynamic hardness meter - Google Patents

Description

The invention relates to a testing technique, in particular to measurements of the hardness of materials.

A device for determining the hardness of a material is known, comprising a tip, BHe7 pHeMbei; in material with a spring drummer. The spring is cocked using a three-pronged wheel and a lever 1 connected to it.

The disadvantage of this device is - low accuracy, since a change in spring stiffness leads to significant errors.

The closest to the proposed technical essence and the achieved effect is a dynamic hardness tester, comprising a housing, a striker located in it, a last indenter and a vibration sensor connected in series to an attenuator, an amplifying unit, a peak detector and a direct current amplifier connected to the output of a vibration sensor , and interacting with the striking elastic element and stopper {21.

However, the accuracy of the known meter remains insufficiently high, since the measurement result

hardness has no variations from testing to testing speed of movement.

5 The purpose of the invention is to increase accuracy.

This goal is achieved by the fact that the meter is equipped with a series-connected polar control, an integrator, a second peak detector controlled by an attenuator, the information input of which is connected to the output of the first peak detector, and the output to the input of a DC amplifier, and

15 the input of the polar discriminator is connected to the second output of the amplifier unit.

The drawing shows the scheme of the proposed meter.

20

Claims (2)

The meter contains a mechanical head 1, installed on the surface of the material under investigation and made in the form of a body 2, the striker 3 located in it, on which the indenter 4 is closed. The elastic element 5 and the vibration sensor 6 are also connected to the striker. The elastic element 5 is connected to the stopper 7 and a blocker 8. The output of the vibration sensor 6 is connected to the input of a series-connected attenuator 9, an amplifier unit 10, a peak detector 11, a controlled attenuator 12, a DC amplifier 13 and an indicator 14. To the second output unit 10 is connected in series with a polar discriminator 15, an integrator 16 and a second peak detector 17, the output of which is connected to the control input of a controlled attenuator 12. The device operates as follows. The head 3.:shifts to the upper position by compressing the elastic element 5. in this position, the striker 3 is held by the stopper 7. When the stopper 7 is released, the striker 3 accelerates by the elastic element 5 to a certain speed and hits the material surface with an indenter 4. When moving A striker 3 at the output of the vibro sensor b, for example, a piezoelectric, appears a voltage proportional to the acceleration value of the striker 3, This voltage is transmitted by an attenuator 9 to the amplifier unit 10, where it is amplified and fed to the input of the peak detector 11, forming an electric signal proportional to the maximum acceleration value) (f and then is fed to the information input of the controlled attenuator 12) From the second output of the amplifying unit 10, the signal enters the input of the polar discriminator 15, where it cuts off a negative signal emission corresponding to the braking of the striker 3 upon hitting the material. The integrator 16 produces a signal proportional to the speed of the striker 3. From the output of the integrator 16, the signal is fed to the input of the peak detector 11, which generates a signal proportional to e- The maximum speed of the Vyy, a, t indenter. This signal is fed to the control input of the attenuator 12, changing its transmission coefficient. Thus, the signal is corrected depending on. the magnitude of the speed of the striker at the moment before hitting the material under study. The signal from the output of the controlled attenuator 12 is amplified by the DC amplifier 13 and fed to the indicator 14. The lock 8 is used to turn off the elastic element 5 when calibrating the meter. Thus, the proposed device allows to take into account the influence of the velocity of the striking speed on the results of measuring the hardness of the material and thereby improving the accuracy of its determination. DETAILED DESCRIPTION OF THE INVENTION A dynamic hardness tester comprising a housing, a firing pin located therein, an indenter and a vibration sensor connected in series, an attenuator connected in series, an amplifier unit, a peak detector, and a DC amplifier connected to the output of the vibration sensor and a resilient element interacting with the striker about the fact that, in order to increase accuracy, it is equipped with a polar discriminator connected in series, an integrator, a second, peak detector controlled by an attenuator, and The information input of which is connected to the output of the first peak detector, and the output to the input of the DC amplifier, and the input of the polar discriminator is connected to the second output of the amplifier unit. Sources of information taken into account in the examination 1. The author's certificate of the USSR 111596, cl. G 01 N 3/48, 1955. 2. Maximov V.N. Acoustic Pribortl for express measurements of the hardness of metals. Sat The use of acoustic methods and devices in science, technology and production, Tbilisi, GruzNITI, 1979f p.75-78 (prototype).