JPH0236107Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a test piece chuck device for holding a test piece in a material testing machine, and in particular, a test piece chuck device that can reliably align the test piece with the axis of the material testing machine. Regarding chuck devices.

Specimen chuck devices have been known for a long time, each of which has a pair of clamps that are movably disposed within the chuck body and which clamp the test specimen. At the same time, the attachments are positioned symmetrically with respect to the axis of the material testing machine, and a tightening piston is connected to each tightening device and both pistons are driven synchronously. Both fasteners are placed close to each other in the radial direction of the test piece to clamp the test piece.

However, in such a conventional test piece chuck device, a small pressure difference occurs in the hydraulic pressure of the cylinder that drives each tightening piston due to the frictional resistance of the pipeline and the machining and assembly precision of the parts, and this pressure difference causes the test The position of the fasteners at both ends of the test piece was misaligned, and there was a risk that the test piece would become slightly eccentric with respect to the axis of the material testing machine. If this test piece is made of a ceramic material that is brittle and has high notch sensitivity, the locally concentrated stress caused by this minute eccentricity may cause cracks or breakage of the test piece, which may impede material testing.

SUMMARY OF THE INVENTION An object of the present invention is to provide a test piece chuck device that eliminates the drawbacks of the conventional devices described above and can reliably align a test piece with the axis of a material testing machine.

The present invention has a screw shaft protruding from one fastener, which is movably screwed into a screw hole formed in the chuck body, and a piston rod protruding from the other fastener. The invention is characterized in that a piston connected to a piston rod is movably disposed within a cylinder formed in the chuck body, and further provided with means for detecting displacement of the screw shaft.

The present invention will be explained below with reference to embodiments shown in the drawings.

A chuck body 3 of a test piece chuck device 2 is protruded from a support shaft 1 extending from the material testing machine so as to coincide with an axis C of the material testing machine (not shown).
In the front of the chuck main body 3, a groove 5 for inserting a flat test piece 4, for example, is provided at the center of the axis C.
is formed to match. Further, in the chuck main body 3, a pair of guide holes 6 are provided which communicate with the groove 5 and have an axis D perpendicular to the axis C.
A and 6B are formed on both sides of the axis C,
In each guide hole 6A, 6B, fasteners 7A, 7B movable in the direction of the axis D are arranged so as to be able to clamp the test piece 4.

A screw hole 9 is formed in the chuck body 3 and communicates with the guide hole 6A through a guide hole 8A having a smaller diameter than the guide hole 6A. A screw shaft 11 is connected to the fastener 7A via the existing rod 10A.
are screwed together. The outer end of this screw shaft 11 has a shaft 1
Knob 13 facing the outside of the chuck body 3 through 2
is provided in a protruding manner, and by rotating this knob 13, the fastener 7A can be moved in the direction of the axis D. A scale 14 extending in the direction of the axis D is engraved on the outer peripheral surface of the shaft 12, and the scale is marked by an indicator plate 15 protruding from the chuck body 3 so as to be located on the outer periphery of the shaft 12. The numbers above 14 can be read.

A cylinder 16 is formed in the chuck body 3 and communicates with the guide hole 6B through a guide hole 8B having a smaller diameter than the guide hole 6B, and the outer end of the cylinder 16 is closed by a cover plate 17. . The tightening tool 7 is inserted into the cylinder 16 via a piston rod 10B extending inside the guide hole 8B.
A piston 18 connected to B is movably arranged in the direction of the axis D. Hydraulic pressure is supplied into the cylinder 16 by a hydraulic device (not shown), and the fastener 7B can be moved in the direction of the axis D by supplying the liquid pressure into the cylinder 16. It's becoming like that.

Note that the fasteners 7A, 7B and the rod 10A,
10B through spherical joints 19A and 19B, respectively.

To hold the test piece 4 with the above-described configuration,
While visually observing the rotational displacement of the screw shaft 11 using the scale 14 and indicator plate 15, rotate the knob 13 to move the fastener 7A to the left in the figure, so that the center of the test piece 4 is aligned with the axis of the material testing machine. When the value matches C, the fastener 7A is stopped. Then cylinder 1
6 to drive the piston 18, the fastener 7B is moved rightward in the figure, and the test piece 4 is held between the two fasteners 7A and 7B. Note that when the fasteners 7A, 7B move in the direction of the test specimen 4, spherical joints 19A, 19B are interposed between the rods 10A, 10B and the fasteners 7A, 7B, so the spherical action of these joints 19A, 19B As a result, both fasteners 7A and 7B come into contact with the test piece 4 in parallel, thereby avoiding applying bending force to the test piece 4 during tightening. Further, the other end (not shown) of the test piece 4 is also clamped by the same test piece chuck device 2 as described above.

According to the embodiment described above, the center of the test piece 4 of one of the fasteners 7A can be aligned with the axis C of the material testing machine using the screw shaft 11, so that eccentricity of the test piece 4 does not occur. . Note that the displacement of the screw shaft 11 may be detected electrically using a potentiometer or the like instead of using the scale 14 and the indicator plate 15.

As explained above, the test specimen chuck device according to the present invention has a screw shaft protruding from one of the fasteners, and this screw shaft is movably screwed into a screw hole formed in the chuck body, and the other fastener is movably screwed into the screw hole formed in the chuck body. A piston rod was provided protruding from the fastener, a piston connected to the piston rod was movably disposed within a cylinder formed in the chuck body, and a means for detecting the displacement of the screw shaft was provided. It has the excellent effect of being able to reliably align the piece with the axis of the material testing machine, and allowing error-free testing of materials such as ceramics.

[Brief explanation of drawings]

The figure is a partially longitudinal sectional front view showing an embodiment of the test piece chuck device according to the present invention. 2...Test piece chuck device, 3...Chuck body, 4...Test piece, 7A, 7B...Tightening tool, 10
A, 10B... Rod, 11... Screw shaft, 14...
...Scale, 15...Instruction board, 16...Cylinder, 1
8... Piston.

Claims (1)

[Scope of utility model registration request] In a test specimen chuck device that is equipped with a pair of clamping tools that are movably arranged inside the chuck body and that clamp the test specimen, a screw shaft is provided protruding from one of the clamping tools, and this screw shaft is attached to the chuck body. The chuck is movably screwed into a screw hole formed in the chuck body, a piston rod is provided protruding from the other fastener, and the piston coupled to the piston rod is movably disposed within a cylinder formed in the chuck body; A test piece chuck device comprising means for detecting displacement of the screw shaft.