SU131898A1 - Piezoelectric profilometer - Google Patents

Description

BASIC Auth. St. No. 95463 is a profilometer for determining the cleanliness of surfaces, consisting of a sensor fitted with a piezoelectric element, rigidly connected with a groping needle, a mechanical drive and an electric booster, made as separate units.

The sensing needle of the sensor is rigidly fixed on the piezoelectric element between the two supporting bashmak moved when adjusting the sensor using a wedge. The piezoelectric element, along with the needle, is positioned on a slide, which can move in the longitudinal direction relative to the housing and the support bar. The body is filled with a moisture-proof mass, for example, petrolatum or lanolin. The sensor is connected to a mechanical drive through a pull through an elastic link. Such a device facilitates the calibration of the device and ensures the stability of its work when the humidity of atmospheric air changes.

In the profilometer being described, the piezoelectric transducer is composed of two bari titanate plates glued together and connected in series, equipped with a damping plate. The piezoelectric transducer is connected via additional capacitance to an amplifier with a large input impedance. The sensor is provided with one forked support with a hole in the middle for the needle to pass through the spring mechanism. These changes make it possible to obtain a maximum signal, independent of the temperature and humidity of the environment, and reduce the errors of the profilometer.

FIG. 1 shows a piezotransducer of the profilometer described, general view; in fig. 2 is a circuit diagram of a series connection of barium titanate plates; in FIG. 3-section sensor; in fig. 4 is a section along the line A-A in FIG. 3

No. 131898-2 -

The piezoelectric transducer of the profilometer described is made in the form of a bimorph piezoelectric element of two barium titanate plates. It is made in the form of a straight square parallelepiped and has an electrically sequential connection of plates. The plate hollowness in the absence of deformation is denoted by @, O, and the actual polarity of the plates during deformation of the piezoelectric element +, -. In order to absorb natural vibrations, the piezotransducer is enclosed in damping plates of microporous rubber or corrugated paper. The piezo transducer is connected via additional capacitance to an amplifier with a large input impedance.

The sensing head of the sensor is made with one forked support /, in the middle part of which there is an opening for the passage of the groping needle 2. Needle 2 is rigidly fixed on the bad element 3 and extends by means of a spring-like mechanism 4 combined with a screw micrometric transmission and a wedge system.

Subject invention

1. Piezoelectric profilometer according to ed. St. No. 95463 for determining the surface roughness, consisting of a sensor equipped with a piezoelectric element, rigidly connected with a groping needle, a mechanical drive and an electric amplifier, made in the form of separate blocks, characterized in that, in order to obtain a maximum signal independent of temperature and ambient humidity, the piezotransducer is composed of two bari titanate plates glued together and connected in series, fitted with a damping plate, and connected through an additional capacitance to preamplifier with a high input impedance.

2. The form of execution by n. 1, characterized in that, in order to reduce errors, the sensor is provided with one forked support with a hole in the middle for the needle to pass through the spring mechanism.

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