RU2350898C1 - Crank-lever indicator tensometer - Google Patents

Abstract

FIELD: physics, measurement.

SUBSTANCE: invention is related to metering equipment and is designed for measurement of deformations. Crank-lever indicator tensometer comprises base, fixed and movable supports with distance between them that make the instrument base and are equal to 100 mm, crank lever, scale for measurement of deformations. At that base is arranged in the form of bar with rectangular cross section, and supports are arranged in the form of "П"-shaped prisms. One of supports is fixed on base, and the other is rigidly fixed to crank lever with lever arms ratio of 5:1, which in its turn is connected to base by means of elastic plate installed perpendicular to longitudinal axis of base that serves as hinged joint and provides for more accurate fixation of preset measurement base, and with its free second end. Scale for measurement of deformations is a micron indicator of clock type installed on base, leg of which rests on free end of crank lever.

EFFECT: higher accuracy of measurement due to increased enlargement factor with simultaneous simplification of device design.

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Description

The invention relates to measuring technique and is intended for measuring strains.

Known lever tensor Hugenberger, including the base, the lever system, fixed and movable supports, a scale for measuring deformation [Test technique. Reference, V.V. Klyuyev, book 2. M.: Mechanical Engineering, 1982. - S.393 - analogue].

The disadvantage of the strain gauge is the design complexity and not a large enough coefficient of increase K = 1000.

Closest to the claimed device is a crank-lever tensometer MIL, including a base made in the form of a bar, movable and fixed supports, a two-stage system of levers and a scale for counting deformations [Belyaev N.M. Laboratory work on the resistance of materials. M .: State publishing house of technical and theoretical literature, 1951 - p.65 - prototype].

The disadvantage of this device is the insufficiently high magnification factor K = 500 and the design complexity due to the presence of a two-stage lever system.

The technical task of the invention is to improve the measurement accuracy by increasing the magnification factor while simplifying the design of the device.

The technical problem is solved due to the fact that in the crank-lever indicator strain gauge containing the base, fixed and movable bearings with a distance between them, which is the base of the device, equal to 100 mm, the crank lever, a scale for measuring deformations, the base is made in the form of a square transverse beam sections, and the supports are made in the form of prisms of a U-shaped shape, while one of the supports is fixedly mounted on the base, and the other is rigidly attached to the cranked lever with a lever shoulder ratio of 5: 1, which in turn the bottom end is connected to the base by means of an elastic plate mounted perpendicular to the longitudinal axis of the base, acting as a hinge, providing a more accurate fixation of a given measurement base, and a free second end, and the strain gauge is a dial-type micron indicator mounted on the base, whose leg leans on the free end of the cranked lever.

, а использование для определения величины деформации микронного индикатора, имеющего коэффициент увеличения K₂=1000, позволяет повысить общий коэффициент увеличения, который составит K=K₁·K₂=5·1000=5000, что значительно превышает коэффициент увеличения в сравнении с прототипом, а исполнение устройства с одноступенчатой рычажной системой не только упрощает конструкцию в целом, но также влияет на повышение точности измерений, что и является новым техническим эффектом заявляемого изобретения.The essence of the claimed invention lies in the fact that the increase in the coefficient of increase K _{1 is} provided due to the design of the lever system, due to the ratio of the shoulders of the lever as

, and the use of a micron indicator having a magnification factor K ₂ = 1000 to determine the strain is possible to increase the overall magnification factor, which will be K = K ₁ · K ₂ = 5 · 1000 = 5000, which significantly exceeds the magnification factor in comparison with the prototype, and the execution of the device with a single-stage lever system not only simplifies the design as a whole, but also affects the increase in measurement accuracy, which is a new technical effect of the claimed invention.

The proposed crank-lever indicator strain gauge is illustrated by drawings:

- figure 1 presents a General view of the crank-lever indicator strain gauge;

- figure 2 - support tensometer.

The crank-lever indicator strain gauge contains a base 1 made in the form of a metal bar of rectangular cross-section, supports 2 and 3. Moreover, the support 2 is fixedly mounted on the base 1, and the support 3 is rigidly attached to the crank lever 4, which in turn is connected to one end the base 1 by means of an elastic plate 5 mounted perpendicular to the longitudinal axis of the base, acting as a hinge, providing a more accurate fixation of a given measurement base, and a free second end. Supports 2 and 3 are made in the form of U-shaped prisms, which allows the installation of the device on both flat and cylindrical surfaces of the test samples. The distance between the supports forms the base of the device l = 100 mm. In addition, on the base 1 there is a micron indicator 6 of the watch type, with a division price of 0.001 mm, the leg 7 of which rests on the free end of the crank lever 4. The micron indicator is designed to take readings of the strain value of the test samples.

, в свою очередь величина Δh фиксируется микронным индикатором, обеспечивающим увеличение K₂=1000, при этом общий коэффициент увеличения составит K=K₁·K₂=5·1000=5000.The device operates as follows. The test sample is installed in the grips of the tensile testing machine. The device on the sample is attached using clamps. When the specimen is axially stretched, the length l increases by the fixed base of the device by Δl. In this case, the support 3 together with the cranked lever 4 will rotate around point A, and the foot 7 of indicator 6 will drop by Δh, which determines an increase in the strain of the sample Δl by 5 times,

, in turn, the Δh value is fixed by a micron indicator, providing an increase in K ₂ = 1000, while the total increase coefficient will be K = K ₁ · K ₂ = 5 · 1000 = 5000.

Thus, the proposed crank-lever indicator strain gauge in comparison with the prototype, having an increase factor K = 500, allows to increase the accuracy of measuring deformations of samples by 10 times, and the use of a single-stage lever system simplifies the design of the device as a whole, which also increases the accuracy of measurements.

Claims (1)

A crank-lever indicator strain gauge containing a base, fixed and movable supports with a distance between them, making up the base of the device, equal to 100 mm, a cranked lever, a scale for measuring deformations, characterized in that the base is made in the form of a bar of rectangular cross section, and the supports are made in the form of prisms of a U-shaped form, while one of the supports is fixedly mounted on the base, and the other is rigidly attached to the cranked lever with a lever arm ratio of 5: 1, which, in turn, is connected at one end to novanie through an elastic plate mounted perpendicular to the longitudinal axis of the base, acting as a hinge, providing a more accurate fixation of a given measurement base, and a free second end, and the scale for measuring deformations is a dial-type micron indicator mounted on the base, the leg of which rests on the free end crankshaft.

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