JP2718282B2 - Test piece positioning device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a test piece positioning apparatus for aligning the center of a test piece with the center (load axis) of a gripper.

[0002]

2. Description of the Related Art Displacement gauges for gripping a test piece and applying a tensile load to a pair of test jigs arranged coaxially with a load axis and tracking a pair of mark marks provided on the test piece. Test methods for measuring the amount of elongation of a test piece using a conventional method have been performed. In such a test, since the test piece gradually narrows as it expands, if the center of the test piece is not aligned with the above-mentioned load axis, that is, if the test piece is not centered, the test piece comes off the load axis. As a result, there is a possibility that the mark cannot be traced by the above-described displacement meter, and the elongation measurement cannot be performed. Particularly, in the case of a soft test piece having a large amount of elongation, the test piece becomes considerably thin due to the tensile load, so that the test piece is easily deviated from the load axis, and the above problem is likely to occur. However, conventionally, since there was no apparatus for centering the test piece, the operator tried to grasp the center of the test piece by intuition so that the center of the test piece was substantially aligned with the load axis, and the gripping tool was taken. In addition, there is a problem that the centering cannot be performed accurately.

An object of the present invention is to provide a test piece positioning apparatus capable of performing the above-mentioned centering operation in a short time and accurately.

[0004]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1 showing an embodiment, the present invention relates to a method of testing a pair of test jigs 5, 6 (FIG. 2) arranged coaxially with a load axis L. The present invention is applied to a test piece positioning device used in a material testing machine that applies a load by gripping a piece TP. A positioning device main body 22 supported by the material testing machine; and a pair of guide members 25a, 25b provided on the main body 22 so as to be able to be separated from and connected to the load axis L, and for holding the test piece TP in the width direction. The guide members 25a, 25b are kept in a state where the pair of guide members 25a, 25b maintain a line-symmetric relationship with respect to the load axis L.
Adjusting means 24A, 24B, 26 for adjusting the interval of 5b
Between the position where the pair of guide members 25a and 25b is inserted between the pair of test jigs 5 and 6 and the position where the pair of guide members 25a and 25b are retracted from the test machine jigs 5 and 6 while the main body 22 is supported by the material tester. And a driving means 21 for driving the main body 22 by using the above means, thereby solving the above problem.

[0005]

The distance between the pair of guide members 25a and 25b is adjusted according to the width of the test piece TP by the adjusting means 24A, 24B and 26, and the main body 22 is adjusted by the driving means 21.
The pair of guide members 25a and 25b are driven to a position where they are inserted between the test jigs 5 and 6. In this state, the test piece is positioned so as to be sandwiched between the pair of guide members, and is gripped by the grippers 5 and 6. Since the distance between the guide members 25a and 25b is adjusted while maintaining a line-symmetric relationship with the load axis L, the test piece can be easily and accurately centered by the above operation.

In the section of the means for solving the above-mentioned problems and the operation which explain the constitution of the present invention, the drawings of the embodiments are used to make the present invention easy to understand. However, the present invention is not limited to this.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. FIG. 2 is a front view of a material testing machine provided with a test piece positioning device according to the present invention. A pair of columns 2 erected on the table 1 has a yoke 3 laid on the upper side and a crosshead 4 supported vertically below the yoke 3. An upper grip 5 and a lower grip 6 are attached to the lower surface of the yoke 3 and the upper surface of the crosshead 4 so as to face each other, and both ends of the test piece TP are held to grip teeth 5a, 6a of upper and lower grips 5, 6 respectively. Each is gripped. Here, as shown in FIG. 3, the gripping teeth 5a, 6a
It is arranged coaxially with the load axis L.

A test piece positioning device 20 for positioning the test piece TP is attached to one of the columns 2. FIG.
FIG. 2 is a perspective view showing details of the positioning device 20.
Reference numeral 1 denotes an air cylinder fixed to the support column 2, and reference numeral 22 denotes a main body connected to the front ends of a pair of rods 21 a of the air cylinder 21 via a bracket 23. The main body 22
Due to the expansion and contraction of the air cylinder 21, a positioning guide 25a, 25b, which will be described later, is moved between an advanced position where the positioning guide 25 is located between the pair of gripping tools 5 and 6, and a retracting position where the positioning guides 25a and 25b are retracted from between the gripping tools 5 and 6. Can be moved.

Inside the body 22, a pair of plate members 24 is provided.
A and 24B are inserted removably to and from the load shaft L. As shown in FIG. 4, a nut 24a having a right female screw formed on the plate member 24A, and a left female screw 2 formed on the plate member 24B.
The nuts 24b formed with the respective 4b are non-rotatably fitted. Also, two positioning guides 25a, 25b are provided on the front surface of each of the plate members 24A, 24B so as to project upward and downward, respectively, and these positioning guides 25a, 25b are provided.
The test piece is clamped between them.

Reference numeral 26 denotes a nut 24a of the plate member 24A.
, And a left male screw portion 26b screwed to the nut 24b of the plate member 24B.
a, 22b so as to be rotatable and immovable in the axial direction. An operating portion 26c is formed at one end of the rotating shaft 26. When the rotating shaft 26 is rotated by the operating portion 26c, the pair of plate members 24A and 24B are in line symmetry with respect to the load axis L. Are driven in the opposite direction (the direction of the arrow in FIG. 1), whereby the positioning guides 25a and 25b also move while maintaining the same relationship.

FIG. 5 shows a displacement meter 50 for detecting the amount of elongation of the test piece TP. The displacement meter 50 has a pair of upper and lower clip-type detection heads 52U and 52L protruding from the displacement meter main body 51. Each of the heads 52U and 52L is
It is possible to move back and forth from the position shown in the figure to the position of the load axis L, and the upper and lower mark lines P provided on the test piece TP.
At L and PU (FIG. 3), the test piece TP is attached so as to sandwich it in the thickness direction. Detection heads 52U, 52
L can be lowered from the position indicated by the solid line to the position indicated by the two-dot chain line in accordance with the elongation of the test piece TP.
The change amount X (= X ₁ −X ₀ ) of the distance between U and 52L is the test piece T.
It is output as the amount of elongation of P.

Next, the operation of the embodiment will be described. Test piece T
In mounting P on the tester, first, the positioning device 20
In the state where the main body 22 is in the retracted position, the interval between the positioning guides 25a and 25b is adjusted according to the width of the test piece TP. That is, when the distance is larger than the width of the test piece TP, the test piece TP is placed between the positioning guides 25a and 25b.
Then, the rotating shaft 26 is rotated by the operation unit 26c, and the plate members 24A and 24B are driven in directions approaching each other until the positioning guides 25a and 25b sandwich the test piece TP in the width direction.

Then, after removing the test piece TP, the air cylinder 21 is extended to drive the main body 22 to the advanced position,
The positioning guides 25A, 25B are positioned between the upper and lower grips 5, 6. Then, with the upper and lower gripping teeth 5a and 6a opened, the test piece TP is moved to each guide 25 as shown in FIG.
The test piece TP is positioned so that the upper and lower sides of the test piece TP can be gripped by the gripping teeth 5a and 6a, and then the gripping teeth 5a and 6a are closed and gripped. At this time, the positioning guides 24A and 24B maintain the line symmetry with respect to the load axis L, and the interval is set to the test piece TP.
, The test piece TP is gripped in a state where its center coincides with the centers of the gripping teeth 5a and 6a, that is, in a state where it is centered with respect to the gripping tools 5 and 6.

Thereafter, the air cylinder 21 is contracted to retract the main body 22 to a position where the positioning guides 25a and 25b are retracted from between the grippers 5 and 6, and the above-mentioned position is moved to the upper and lower marking line positions PU and PL of the test piece TP. The detection heads 52U and 52L of the displacement meter 50 are respectively attached, and in this state, the crosshead 4, that is, the lower grip 6 is lowered to apply a tensile load to the test piece TP. Thereby, the test piece TP
Is extended, and the detection heads 52U and 52L follow the reference points PU and PL and descend according to the extension.

At this time, since the test piece TP gradually narrows as it expands, if the test piece TP is not in the centered state, the test piece TP comes off the load axis L, for example, comes off to the right in FIG. In this case, the detection heads 52U and 52L, which can move only to the load axis L, come off the test piece TP, and the elongation cannot be detected. According to the present embodiment, the test piece TP is centered with respect to the grippers 5 and 6 by the above operation, so that even if the test piece TP becomes considerably thin, it does not come off the load axis L, and the detection head 52U, 52L can be prevented from coming off the test piece TP. Therefore, even a soft test piece having a large elongation amount can reliably detect the elongation amount.

During the test, the positioning guide 25 is used.
Since the a and 25b are retracted from between the grippers 5 and 6, they do not hinder the mounting of the displacement gauge, and the guides 25a and 25b abut on the test piece TP during the test to apply an eccentric load. Without this, accurate test results can be obtained.

In the structure of the above embodiment, the upper and lower grips 5, 6 connect the pair of tester jigs to the positioning guide 25.
a and 25b connect a pair of guide members to plate members 24A and 24A.
B and the rotating shaft 26 constitute adjusting means, and the air cylinder 21 constitutes driving means.

In the above description, the interval between the positioning guides 25a and 25b is adjusted in a state where the main body 22 is at the retracted position. However, this adjustment work may be performed at the advanced position. The positioning guide 25 is provided by a screw mechanism.
a and 25b are driven, but the positioning guide 2
As long as 5a and 25b move while maintaining the line symmetry with respect to the load axis L, the driving method does not matter. An actuator such as a motor may be provided to adjust the distance between the positioning guides 25a and 25b. Further, the shape and the number of the positioning guides 25a and 25b are not limited to those in the embodiment, and the positioning guide may be configured by, for example, a plate-like member extending in the vertical direction.

Further, the marked line of the above-mentioned test piece was
In the case where a displacement meter of a type that optically detects at the time and detects the amount of elongation following the movement is used, the same problem as described above occurs when the test piece comes off the load axis L. The invention is equally applicable. The driving means is not limited to the air cylinder 21, and the configuration of the grippers 5, 6 is not limited to the embodiment. Further, the present invention can be applied to a tester of a type in which the upper grip 5 is driven to apply a tensile load to the test piece.

[0020]

According to the present invention, the distance between the pair of guide members can be adjusted while maintaining a line-symmetric relationship with respect to the load axis, and the guide member is positioned by sandwiching the test piece. Therefore, the work of centering the test piece can be performed accurately in a short time. In particular, since the positioning device main body holding the guide member is supported by the material testing machine, the test piece can be very accurately centered on the load shaft determined by the material testing machine.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a test piece positioning apparatus according to one embodiment of the present invention.

FIG. 2 is a front view of a material testing machine provided with the positioning device.

FIG. 3 is a diagram illustrating a centering operation of a test piece.

FIG. 4 is a plan sectional view showing a part of the positioning device.

FIG. 5 is a side view showing an example of a displacement meter.

[Explanation of symbols]

 Reference Signs List 5 Upper gripper 5a Gripping tooth 6 Lower gripper 6a Gripping tooth 20 Test piece positioning device 21 Air cylinder 22 Main body 24A, 24B Plate member 24a, 24b Nut 25a, 25b Positioning guide 50 Displacement gauge PU, PL Marking point position TP Test piece

Claims (1)

(57) [Claims] 1. A test piece positioning apparatus for use in a material testing machine for applying a load by gripping a test piece on a pair of test jigs arranged coaxially with a load axis, wherein the apparatus is provided with a support for the material testing machine.
A positioning device main body to be held, a pair of guide members provided on the main body so as to be able to be separated from and connected to the load shaft, and holding the test piece in the width direction, and the pair of guide members being the load shaft. Adjusting means for adjusting the distance between the guide members while maintaining a line-symmetric relationship with respect to the main body;
A driving unit for driving the main body between a position where the pair of guide members is inserted between the pair of test jigs and a position where the pair of guide members is retracted from the test device jig while the material tester holds the pair of guide members. A test piece positioning device, comprising: