SU432328A1 - DEVICE FOR MEASUREMENT ^ TRANSFER DEFORMATIONS OF BEAMS ^ - Google Patents

Description

I

The invention relates to the field of linear measurements and can be used to measure transverse deformations, as well as vertical displacements of the objects under study.

Devices for transverse beams are known that contain a cable, one end of which is rigidly embedded in the ground, and the other end with a counterweight is passed through a clock-type indicator roller, the deflection of the truss at the indicator location is determined by the position of the arrow.

A disadvantage of the known construction is the insufficient accuracy of information retrieval due to small object displacements.

The proposed device allows one to increase the accuracy of deformation recordings because one of the prisms is fixed and the other on which the light source beam is fixed is mounted on a frame moving vertically using an additional torsional irregularity associated with the counterweight. For automation and remote transmission of information, the light beam in the device is scanned by a photosensor mounted at the end of the rod connected to the coding disk of the displacement sensor and the pulse counter of the reference system.

FIG. 1 is a simple version of the concept of the device described; in fig. 2 is a prism amplifier shifting the light beam; in fig. 3 - operation of the iridescent displacement amplifier of the light beam in combination with the additional torsion gear.

The device (Fig. 1) contains a base / rigidly embedded in the ground, to which one end of the cable 2 is attached, slung over the block 3, installed at the controlled point of the truss 4. At the other end of the cable 2, a counterweight 5 is fixed, which moves along the vertical guide 6. Counterweight 5 contains a light source 7, a collimator 8 (for example, a lens or a lens system) and a diaphragm 5. The additional torsion gear contains a cable thrown over the block / (cable //, one end of which is fixed on the lower part of the counterweight 5, and its other end - on the lower part of the frame 12, as well as the cable 14 thrown over the block / 5, one of which is fixed to the upper part of the frame 12, and a load 15 is attached to its other end. On the frame 12, moving vertically along the guides 16 (Fig. 2) , a rectangular prism 17 is fastened. In front of the prism 17 my prism 18 is fixedly fixed on the body, turning the light beam in the direction of the matte screen 19. On the other side of the screen 19 there is a photo3 diode 20 moving along the screen plane. The photodiode 20 is mounted on a displacement sensor rod 22, made on the basis of a dial-type indicator, on which the arrows are replaced by a coding disk 23 with 5 holes arranged around the circumference with uniform pitch. A light bulb 24 and a photodiode 25 located on opposite sides of the disk 23 serve to form counting pulses. The relocation of the rod 21 is carried out by a drive consisting of an electric motor 26, on whose shaft a cam 27 is mounted. In the initial state, this cam does not touch the rod 21 and the power supply circuit of the electric motor 15 is opened by means of a switch 28 that contacts the protrusion 29 side of the cam. Converters 30-31, converting light signals into electrical ones, are also included in the device circuit. The function block of the control unit contains the drivers 32 and 33, the trigger 34, the valve 35, the pulse counter 36 and the start button 37. The device operates as follows.25 When the start button 37 is pressed, the supply voltage is applied to the motor winding through the upper pair of its contacts 26, and the cam 27 begins to rotate. In this case, a limit switch 28 is activated, by which the power supply circuit of the electric motor 26 is self-blocking for the time of the complete cam rotation. When the trigger button 37 is released, the lower pair of its contacts flips the trigger 34 to a state where the valve 35 changes to the open state. Rotating, the cam 27 enters a € 0 contact with the brush 21, which begins to move the photodiode 20. At the same time, the disk 23 begins to rotate, modulating the light flux of the light bulb 24 on the photodiode 25. The converter 30 produces electrical signals that the driver 32 converts into counting pulses. These pulses are passed through 45 open valve 35 to a pulse counter, where they are recorded. When the photodiode 20 passes through the image of the light beam on the screen 19, the transducer 31 produces an electrical signal. This signal arrives at shaper 33, which is converted into a trigger pulse, applied to the second input of trigger 34. Trigger 34 overturns into its other steady state, in which valve 35 closes, causing the counting pulses to pass to pulse counter 36. The pulse counter 36 records the number of pulses N, proportional to the coordinate of the light beam on the screen, which is defined as: L Lb, where b is the "price of one pulse (µm). So, if hi was recorded in the initial measurement, and after some time the result Aj Lab was obtained, then the deflection bar of the truss is h „2 - h8 (N2-L). At the end of the complete rotation cam 27, the system returns to its original state This is followed by the next measurement of the start button. The entire cycle described is repeated. The combination of a prismatic displacement amplifier of a light beam with a torsion transmission allows the device shown in FIG. 1, to achieve a fourfold increase in the amount of displacement of the light beam on the screen. This is evident from FIG. 3, where the point A is the initial level of the light beam; the point is the level of the light beam after the truss deflection, and the points L and are the image levels of the corresponding rays on the screen. The dashed line in FIG. 3 shows the position of the prism 17, which it occupies after the truss deflection, the subject of the invention. A device for measuring transverse deformations of beams, comprising a flexible thread thrown through a block with an indicator fixed on it, a housing and a recording device, in order to improve the accuracy of deformation recording. , it is equipped with an additional torsion gear, on a movable filament of which a rectangular prism is reversed, facing the right angle to the fixed prism located on the body, and prisms are shifted relative to each other in the direction of movement of the movable prism. 7y 7 -: ry7y ° // ° 7 ° / 7 /% / 7 ° fig- /

 sixteen

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FIG. 2

18

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