SU41231A1 - Spring extensometer - Google Patents

Description

Elastic extensometers with optical readout of their indications are already known, with sharpened rods at both ends for transmitting movement to the mirror indicator, and the device itself is attached to the sample under test with clamps of the type commonly used in the Guggenberger extensometers.

The present invention aims to increase, to the extent possible, the sensitivity of an extensometer of this type to the smallest deformation effects in the test specimens, as well as to enhance the accuracy of the readings of the instrument through the use of specially hinged gears in the instrument to the optical part of the instrument directly associated with the test specimen.

In the schematic drawing of FIG. 1 shows a perspective view of the proposed extensometer; FIG. 2 and 3 are a bottom view and a side view of the frame carrying the instrument mirror.

The main part of the proposed device is an elastic bracket, in the grooves of the upper arm / which a fixed supporting rod 2 is attached, and in the lower shoulder 3 a second and supporting rod 4 are fixed, as well as a frame 5 carrying the mirror 6.

The shoulders / and 5 of the staples are connected to each other on one side by an elastic plate 7; A spacer stop 8 is placed between their other ends, one of the supports of which is made in the form of a rod 20 bilaterally pointed on both sides, which allows the tips of the supports to lie tightly in their sockets, even if there are inaccuracies in the manufacture of the device.

The mirror frame 5 is a plate with protruding from the sides supporting prisms 2J, carrying a prism 22 (Fig. 2 and 3), attached by a screw 23 from the bottom. In addition to the screw 23, three stop screws 24 are screwed into the bottom prism and serve to adjust the distance nor between the side prisms 2 / and the bottom prism 22.

The edges of the lower prism 22 abut against the stem JO, and the latter against the end of the screw //, which serves to adjust the position of the mirrors (for example, when set to zero). Screw 7 / to avoid backlash is tightened in the spring slotted nut 25. The side prisms 2f of the frame 5 are placed in the slots of the plug 72, which is part of the upper arm of the device bracket 7, and the frame 5 itself is pressed against the rod 10 by two springs J3 (Fig. 2 and 3).

The extensometer is attached to the test sample with a clamp

or any other device; the support rods 2, 4 brackets /, 3 are supported on the surface of the sample to be tested. Upon deformation, the rod 4 is moved, which causes a rotation of a certain angle of the mirror 6.

In the device, the sliding friction is almost absent and the relative movement of the support rods 2 4 is possible only due to the elasticity of the connecting plate 7.

The possibility of counting is achieved by the fact that the focus of the lens / b is placed slightly further than the actual image transmitted by the lens 15, which further with increasing its size is transmitted to the observer by the lens 18, the focal length of this lens can be the same as that of the lens. With the aid of the prism 26, the angles of observation are measured. Dp scale / 7, curved along a cylindrical surface, requires illumination of its divisions. With sufficiently strong illumination, the chalcals can be used to obtain a projection of tick marks on a screen placed against the pipe.

The subject matter of the invention.

A spring extensometer with an optical readout, characterized in that the holder for the support rods in it is made in the form of an elastic bracket, one arm 7 of which is intended for a hinge suspension to it loaded with springs 75 of the mirror 6, and the second 3 provided with support rods 4 and a hole to pass through it the second support rod 2, is intended as a support for the hinge limiter 8 limits of the displacement of the arms of the bracket /, 3 one relative to another.

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