JPH1151833A - Clamping jig for tensile test - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a clamping jig for tensile test which can secure parallelism to a test direction and obtain accurate measured values immediately particularly when a test piece is set to a test piece-holding apparatus. SOLUTION: At least one of an upper and a lower chucking clamping jig 2 of a test piece-holding apparatus holding an end part of a test piece 1 has a temporary clamping contact element 3 at a test piece-holding part of the clamping jig of an axial center part of an opposite clamp face which applies a test piece-supporting force in a vertical direction to a test piece 1 at the beginning when the test piece is set, and a burying mechanism for the contact element 3 which freely moves the contact element 3 forward and rearward to the clamp face thereby burying the contact element 3 in the clamp face and supporting the test piece 1 at the whole clamp face when the temporarily clamped test piece 1 is to be perfectly clamped. The contact element 3 is constituted of an elastic body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clamp for a tensile test piece, and particularly, when mounting a test piece on a test piece gripping device, it is possible to secure parallelism with respect to a test direction and quickly obtain accurate measurement values. The present invention relates to a clamp jig for a tensile test.

[0002]

2. Description of the Related Art In a tensile test, the main purpose is to obtain a stress-strain diagram.
It must be done quickly and efficiently. JIS
In such standards, it is set on the assumption that the test piece is set correctly in the axial direction of the test piece by a certified testing machine, breaks near the reference point of the specified test piece, and the stress at that time becomes an important index. I have. For this reason, it is important for the person who performs the test to set the test piece with great care.

On the other hand, in a test for quality control of an actual production line or the like, the efficiency of the test is an even more important factor. From this point, conventionally, in order to eliminate factors that directly affect the test value such as the inclination of the test piece due to human power, it takes time to adjust the test piece to be set vertically downward. For this reason, accurate setting in the axial direction to obtain quick and accurate data has been a problem. This is the setting of test pieces by visual measurement by a tester, and even a skilled worker checks the parallelism after clamping the test pieces and resets the test pieces again, which makes the work complicated. Further, since the parallelism is not obtained, an abnormal stress is applied to a local portion of the test piece, which causes a problem that accurate data cannot be obtained.

As described above, there is no conventional simple and efficient method for clamping a tensile test piece in an attempt to secure parallelism between the test direction and the tensile direction. In general, a clamp jig for a plate-like tensile test is one in which a test piece is inserted into a chuck portion and a clamp surface is tightened to chuck the test piece. However, the direction of the test piece in the initial stage of setting does not become parallel to the tensile direction. It is desired that a simple method is used to prevent the occurrence of variation in test data by a method for correcting this.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a clamping jig for a plate-like tensile test in which a test piece is inserted into a chuck portion and a clamping surface is tightened to chuck. A method for correcting the initial test piece direction and the tensile direction so as to be parallel to each other is studied, and a simple and efficient clamp jig is provided. Another object of the present invention is to study a method capable of clamping a test piece in parallel to a clamping surface of a clamp jig for a plate-like tensile test at the time of temporary clamping, realizing this with a test piece pressing pressure contactor, and An object of the present invention is to provide a clamp jig in which the contact is buried at the time of regular clamping so that the entire surface of the clamp surface can be clamped.

Another object of the present invention is to provide a function of burying the contact at the time of the regular clamping by manufacturing the contact with an elastic body as a method capable of clamping the test piece in parallel during the temporary clamping. An object of the present invention is to provide a clamp jig that can improve the accuracy of chucking.

[0007]

The object of the present invention is to provide at least one of a clamp jig for vertical chucking of a test piece gripping device for holding an end of a test piece,
At the axis of the opposing clamp surface, to the test piece gripping part of the clamp jig, a temporary clamp contact for applying a test piece supporting force to the test piece in the vertical direction at the beginning of the test piece setting,
Next, at the time of clamping for completely gripping the test piece in the temporarily clamped state, the contact burying mechanism that allows the contact to be able to advance and retreat with respect to the clamp surface so as to be buried in the clamp surface so that the test piece can be supported on the entire clamp surface. This is achieved by a tensile test clamp jig having the following features.

The above object is also achieved by the tensile test clamp jig, wherein the contact is made of an elastic material. Although tensile tests of plate materials are widely performed, it is an essential issue to obtain accurate data to make the test piece direction parallel to the tensile direction when setting the test piece, and the present invention In order to solve the problem, a point contact type preliminary clamp pin is provided inside a clamp jig to achieve a mechanism in which the test piece direction is easily parallel to the tensile direction by the weight of the test piece.

In a tensile test, which is a general test for a plate material or the like, a clamp jig capable of setting a test piece in parallel to a tensile direction, wherein a test piece is easily positioned in a vertical direction at the time of temporary clamping by a contact. And quickly.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A conventional clamping jig performs chucking while inserting a test piece, so that if the test piece is tilted when the test piece is inserted, it will be clamped as it is. If the test is carried out as it is, local stress concentration and non-uniform deformation may be caused, and accurate data may not be collected.

[0011] Further, securing the degree of parallelism at the time of insertion depends on visual observation, and is a task that requires carefulness, such as re-setting of a set even by a skilled person. In the present invention,
The test piece can be positioned in the vertical direction at the time of temporary clamping by the contact. In addition, the burying mechanism of the contact can be also used by the elastic body. Therefore, the clamping accuracy of the test piece is improved,
This prevents a drop in the reliability of test data due to the test piece direction and the tensile direction not being parallel. Further, the work for making the test piece direction parallel to the tensile direction is facilitated. The elastic body of the present invention may be any as long as it exhibits elastic behavior in mechanical properties, and does not particularly define its material shape and size. Examples of the material include not only metals, but also materials other than metals that have thermosetting and thermoplastic ceramic spring properties and those that are finished into a shape for pressing, materials made of other high-polymer materials, and materials and shapes obtained by combining them. And the like. Hereinafter, the present invention will be described in more detail with reference to Examples.

[0012]

【Example】

Embodiment 1 This embodiment relates to the first invention, and its outline is shown in FIG. FIG. 1A shows a state of an upper chuck portion where a test piece 1 is temporarily clamped by a clamp jig 2 via a contact 3. FIG. 1B is a diagram when FIG. 1A is rotated by 90 degrees. In the first invention, a spring 4 (coil spring, leaf spring) is provided on a clamp surface in a clamp jig.
And a clamp jig having a contact ball 3. As can be seen from these figures, when the test piece 1 is inserted into the clamp jig 2, the contact ball 3 is pressed against the test piece 1 by the spring 4 and the test piece 1 is pre-clamped, and is parallel to the downward direction with respect to the tensile direction. Is set to

FIG. 4 shows a conventional method as a comparison. FIG.
(A) shows the entire test piece holding device 8, and FIG. 4 (a) is a side view thereof. FIG. 4C shows a state in which the clamp jig 2 holds the test piece with the screw 7. If they are not parallel, the test piece will be inclined as shown in FIG. 4D, and in this case, accurate data cannot be obtained. On the other hand, in the present invention, the test specimen 1 rotates around the contact point with the contact ball 4 by its own weight by the temporary clamp of FIG.

At this time, the most suitable spring constant is used depending on the size of the test piece and the like. Thereafter, by performing the main clamp with the original clamp jig, the test piece direction is kept parallel to the tensile direction. Further, the present invention may be applied to the other downward chucking portion instead of the upper portion, and the effect is basically the same, and the temporary clamp causes the test piece 1 to be in contact with the contact ball 4 by the clamping force. The test piece rotates around the contact point of (1) and the direction of the test piece is stabilized vertically upward.

Embodiment 2 This embodiment relates to the second invention. The outline is shown in FIG. FIG. 2 shows a state of the upper chuck portion where the test piece 1 is temporarily clamped by the clamp jig 2 via the contact 3. At this time, in the present embodiment, a clamp jig provided with an elastic body and a contact ball on a clamp surface in the clamp jig is used for the spring 4 of FIG. The contact ball 3 is pressed against the test piece 1 by the elastic body 5 by the same mechanism as in the first embodiment, and the test piece 1 is pre-clamped. Thereafter, as in Invention 1, the specimen direction is kept parallel to the tensile direction.

Embodiment 3 This embodiment is basically related to the second invention.
The outline is shown in FIG. FIG. 3 shows a state of the upper chuck portion where the test piece 1 is temporarily clamped by the clamp jig 2 via the contact 6. At this time, in the present embodiment, the contact portion with the test piece is provided with an elastic body on the clamp surface in the clamp jig,
A clamp jig in which the contact area is limited so that the test piece can be rotated. The test piece 1 is pre-clamped by the elastic body 6 on the clamp surface in the clamp jig 2, and the test piece is similar to the test pieces 1 and 2. The direction is kept parallel to the tensile direction.

[0017]

According to the present invention, the setting of the test piece in the tensile test can be maintained in parallel by the temporary clamp, and the contact used in the temporary clamp is retracted and buried at the time of the main clamp, so that the clamp surface is provided. It is possible to provide a clamp jig that can be fixed on the entire surface, thereby improving the accuracy of data as compared with the related art, and performing a tensile test efficiently.

[Brief description of the drawings]

FIGS. 1A and 1B schematically show a clamp jig according to a first embodiment of the present invention, wherein FIG. 1A shows a temporary clamp, and FIG.

FIG. 2 is a diagram illustrating an outline of a clamp jig according to a second embodiment of the present invention.

FIG. 3 is a diagram illustrating an outline of a clamp jig according to a third embodiment of the present invention.

FIG. 4 shows an outline of a conventional clamp jig, in which (a) shows the entire clamp, (b) is a clamp view, (c) is a clamp situation, and (d) is a view showing a clamp failure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Test piece 2 ... Clamp jig 3 ... Contact 4 ... Spring 5, 6 ... Elastic body 7 ... Tightening screw 8 ... Test piece holding device

Claims (2)

[Claims] In at least one of the upper and lower chucking jigs of a test-piece gripping device for holding an end of a test piece, a test piece of the clamp jig is held at an axial center of an opposing clamp surface. At the beginning of the test piece setting, the gripper is provided with a contact for temporary clamping that applies a test piece supporting force to the test piece in the vertical direction, and then the contact is clamped at the time of clamping to completely hold the test piece in the temporarily clamped state. A clamp jig for a tensile test, comprising a contact burial mechanism that is immersed in the clamp surface so as to be able to advance and retreat with respect to the surface, and is capable of supporting the test piece on the entire clamp surface. 2. The tensile jig according to claim 1, wherein the contact is made of an elastic material.