JPS6047941A - Grip for tensile test - Google Patents

Abstract

PURPOSE:To enable the working of a large tensile testing load by providing a grip frame body, a pair of slide piece changeable in the opposed interval guided by a slope formed thereon and a pair of grip piece capable of grasping a test piece. CONSTITUTION:A frame body 2 of a rigid structure is mounted on a tester with a mounting screw 22. A space 5 with one open end is provided at the center of the frame body 2. Slide pieces 3a and 3b are positioned in the space 5. The slide pieces 3a and 3b are positioned opposite to each other, keyways 7a and 7b are formed on the backs thereof, slidably contacting slopes 6a and 6b of the frame body 2. Grip pieces 4a and 4b are supported on the slide pieces 3a and 3b through rotating shafts 8a and 8b. The grabber pieces 4a and 4b are positioned opposite to each other and a test piece 10 is grasped between opposed gripping surfaces 11a and 11b. The grip surfaces 11a and 11b have saw pitches formed thereon perpendicular to each other with a conical sectional shape and can hold a test piece in any rotating direction.

Description

[Detailed Description of the Invention] This invention relates to a tensile test gripping device, particularly for tensile testing used in tensile testing of anisotropic materials, uniaxial load testing of asymmetric test pieces on a loading lane, such as fracture toughness testing, etc. This relates to gripping tools.

When performing a tensile test, in the case of a normal test, the direction of the test load and the direction of deformation coincide, and the test piece undergoes elongation deformation in response to the tensile test load, but in the case of an anisotropic material In the case of a specimen with a notch on one side, the load direction and the deformation direction do not necessarily match, and shearing deformation and bending deformation occur along with elongation in response to a tensile vJ load. Usually, J
3. The test piece gripping tool used in this method holds the test piece by holding the end of the test piece between the pair of gripping pieces, and has the advantage of a simple structure and reliable holding. However, when this type of grip is used for tensile testing of anisotropic materials, the grip restrains the shear and bending deformation that would occur due to the application of a tensile load, and the shear horns and bending moment are Even if a universal joint or the like is used, an accurate uniaxial load tensile test cannot be performed because the load is applied to the piece. To solve this problem, the specimen is held by a bottle support, but this type of bottle holding type has a mounting hole at the end of the specimen, and the bottle is inserted into the hole. The test piece can be taken into the testing machine through the bottle, and the test piece can be rotated using the margin between the hole and the bottle, and a tensile load is applied. This method does not restrict the shearing or bending deformation of the test piece, allowing correct tensile testing to be performed.However, with this bottle support, the test load concentrates on the hole where the test piece is attached. Because of this, it is easy to break from the hole, and it is difficult to apply a large test weight to it.

Because of this, it is possible to apply a large tensile test weight in tensile tests and fracture toughness tests of anisotropic materials, and the I! lvl! It is desired to develop a tensile test grip that does not restrict l'i deformation or bending deformation.

This invention was made in view of the above circumstances, and it is possible to apply a large tensile test load in the tensile test and fracture toughness test of the anisotropic moon 11, and it is possible to reduce the shear deformation of the test piece. The object of the present invention is to provide a tensile test grip that does not restrict bending deformation.

Corresponding to this purpose, the tensile test gripping tool of the present invention is located opposite to the gripping tool frame to be attached to the tensile testing device, and is guided by an inclined surface formed on the gripping tool frame and facing the gripping tool frame. a pair of sliding pieces that can change the distance +1A;
It is characterized by comprising a pair of gripping pieces that can hold the test piece.

Hereinafter, the details of this invention will be explained with reference to the drawings showing actual examples.

In FIGS. 1, 2, and 3, C11 is a grip for tensile testing. A pair of gripping tools 1 are provided corresponding to both sides of the test piece 10. The gripping tool 1 includes a frame 2, sliding pieces 3a, 3b, and -41 gripping pieces 4a, 4b.

The frame 2 has a rigid structure and is attached to a testing machine (not shown) with screws 22. A space 5 with one end open is provided in the center of the frame 2.

Opposite slopes 6a and 6b are formed on the side surface of this space 5, and are located toward the open end 9 in sequence.

Inside the space 5 are sliding pieces 3a and 3b. Slip piece 3
a and 3b are located opposite each other, and guide surfaces 7a and 7b are formed on the back surfaces of each of the guide surfaces 7a and 7b.
b is in slidable contact with the slopes 6a and 6b of the frame 2. Therefore, the sliding piece 3a.

3b is guided within the slopes 6a and 6b and is movable within the space 5, and as it approaches the space 9 between the frame body 2, the opposing distance becomes smaller.

The sliding pieces 3a, 3b are connected to the gripping pieces 4a, 4 through rotating shafts 8a, 8b. b is supported. This gripping piece 4a
, 4b are located opposite to each other, and the opposing gripping surfaces 11a,
The test piece 10 is held between the parts 11b and 11b. The gripping surfaces 11a and 11b are formed with serrations having a chevron-shaped cross section orthogonal to each other, so that the test piece can be held in any direction of rotation. Thrust rolling bearings 12a, 12b are provided between the rotating shafts 8a, 8b and the sliding pieces 3a, 3b, so that the rotating shafts 3a, 3b are connected to the sliding pieces 3a.

Rotation @ 8a with respect to 3b, the gripping pieces 4. are freely rotatable around the center of Bb and are fixed to the tips of the rotating shafts 8a, 8b. A and 4b are also freely rotatable with respect to the sliding pieces 3a and 3b. A positioning hole 13 is formed in the center of the gripping surface 11a.
Position the bin 14 at a position on the gripping surface 1111 opposite to the
is provided prominently. The hole 13 and the positioning pin 14 are the positioning hole 1 formed in the test piece 10.
This is to engage with the test piece 5 and position the test piece 10 when taking the test.
There is no device C for applying a tensile test load to.

A hole 23 is formed in the center of the frame 2, and the hole 2
The frame body 2 is attached to the flange portion 25 of the support cylinder 24 inserted through the
are engaged with each other, and the support cylinder 24 can be rotated relative to the frame 2. This support cylinder 24 is attached with an inner screw 2G (= screwed together with the outer screw 27 of the JG screw 22), and a handle 28 is attached to the support cylinder 24 with a bolt 31 (=
It's J-ke. Therefore, when the handle 28 is rotated, the frame body 2 is linearly displaced with respect to the handle screw 22 in the fixed position, and the grippers 4a and 14b approach or
Ru. However, the spring 32 is always connected to the frame 2 and the sliding pieces 3a, 3.
Since it acts in the direction that separates b by 1111 points, the gripping piece 4
The opposing distances between a and 4b tend to be farther apart.

When carrying out a tensile test using the gripping tool configured in this way, both ends of the test piece 10 are inserted into the positioning holes 15.
Position it between the grip pieces 4a and 4b using the In this state, no tensile test load was applied to the test piece 10. Next, when the handle 28 is rotated and the frame 2 is pulled up, the sliding pieces 3a13b and the gripping pieces 4a, 4 are in place.
．． b are guided by the slopes 5a and 5b, and approach each other by narrowing the distance between them, and finally work together to clamp the end of the test piece 10.

In this state, when the tester (not shown) is operated to pull up the frame 2, a tensile test load is applied to the test piece 10, causing the test piece 10 to deform.

Even if this deformation includes shearing deformation or bending deformation in addition to elongation, the gripping pieces 4a and 4b are connected to the rotating shaft 3a,
Since it is rotatable around the center of 8b, the test piece 10
The shear deformation and bending deformation of the axle are not constrained, making it possible to perform accurate axle load tensile tests.

[Brief explanation of the drawing]

Fig. 1 is a partially sectional front view showing a gripping tool according to an embodiment of the present invention, Fig. 2 is a plan view of parts shown in Fig. 1;
FIG. 3 is a partial plan view showing the gripping tool shown in FIG. 1...Gripping shell 2...Frame body 3a, 3b...4
1 piece 4a, 4b...Gripping piece 6a, 6b...Slope 7a, 7b...Guiding surface 8a, 8b...Rotating shaft 10...Test piece 12a, 12b...Elast rolling bearing Figure 2 Figure 3 Figure 8

Claims (1)

[Claims] A grip shell frame body to be attached to a tensile test device, a pair of erasable pieces located opposite to each other and whose facing distance can be changed by being guided by slopes formed on the grip frame body; A tensile test gripping tool comprising a pair of gripping pieces supported by the sliding piece via a rotating shaft and working together to clamp the test piece by 1η.