JP2001264029A - Thin-wire extensometer and thin-wire extension measuring instrument using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin-wire extensometer, capable of preventing tensile force in a tensile test from being deviated due to bending moment, and a thin- wire extension measuring instrument using the same. SOLUTION: This thin-wire extensometer 20 consists of a fitting for a thin wire and clipping jigs 30. The fitting has a rod 21 with a fit-in groove 28a formed therein and a rod 22 with a fit-in groove 28b formed therein. The rod 21 is partly inserted into the rod 22, to make an extensible rod as whole. Part of the groove 28a and part of groove 28b are overlapped with each other to true up the grooves in a straight line. The thin wire 1 is fitted into the grooves over their entire lengths. The jigs 30 are used to fix the thin wire 1 at gauge marks to the rods 21, 22. The rod 21, 22 are prevented from relatively turning about their axes by a turn-lock pin 24 and a turn-lock block 26, and the rods 21, 22 are inhibited from extending/contracting by fastener screws.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin wire extensometer used for a thin wire tensile test and a thin wire elongation measuring apparatus using the same.

[0002]

2. Description of the Related Art The measurement of the relationship between stress and strain of a general material and the Young's modulus is performed using a material testing machine such as a tensile testing machine. In the tensile test, since it is necessary to apply a uniform tensile force to the cross section of the test piece and to sufficiently generate deformation up to breakage, for example, a test piece used for a tensile test of a metal material is Specified by JIS Z 2201. Which test piece to use depends on the provisions of each material standard.

[0003] The tensile tester uses an extensometer directly attached to an attachment portion for determining the gauge length of the test piece.
It was common to measure the elongation that occurred in the specimen.

[0004]

However, when a conventional technique using an extensometer is applied to elongation measurement of a fine wire, various difficulties arise.

FIG. 8 shows an example of a conventional contact-type elongation measuring apparatus. In this elongation measuring apparatus, mounting portions 105 and 106 are directly mounted at positions of reference points X and Y of a thin line 101 which is a test piece. At both ends of the thin wire 101, a thin wire end fixing device 10 is provided.
7 and 108, and these fine wire end fixing tools 107 and 1 are fixed.
08 is tensioned by a tensile tester (not shown) to apply tension to the fine wire 101, thereby performing a tensile test on the fine wire 101.
At this time, the universal joint 102 does not prevent the gauge length (X-Y) from expanding due to the tensile test, and the change of the gauge length is
For example, the measurement is performed by the displacement measuring device 103 using the measurement of the induced current by electromagnetic induction.

When the rigidity of the object to be measured for elongation is small, such as the thin wire 101, the elongation measuring device is connected to the hanging string 104.
It is necessary to remove the influence of the own weight of the elongation measuring device on the thin line 101 by hanging the elongation measuring device, etc., but it is difficult to attach the elongation measuring device so that the hanging points do not apply force to the reference points X and Y. It is.

Further, if the gauge length is increased by the tensile test, the center of gravity also changes. Therefore, as shown in FIG.
The unbalanced forces F ₁ and F ₂ are applied to the wires 5 and 106 to generate a bending moment in the thin wire 101, thereby changing the tension applied to the thin wire 101 or, in some cases, as shown in FIG. The fixing portion 110 of FIG.
Shear force F ₃ to disconnection occurs in the vicinity of the mounting portion 107, etc.) shown in. Therefore, it was difficult to perform a tensile test on the thin wire 101 to apply a small load. The thin line 101 is the thin line 10
Due to the rigidity of the thin wire itself such as the bending habit attached to No. 1, it was difficult to attach and align the extensometer, maintain the gauge length of the extensometer, attach it to a tensile tester, measure the elongation, and the like.

[0008] In response to this, the state in which the test piece is stretched by the camera is captured and analyzed as an image, and the spectrum pattern generated by the irradiation of the laser beam is tracked as a virtual reference point, so that the test piece can be contacted without contact. Although there is a method of measuring elongation, it is difficult to capture an image or a spectral pattern because a fine wire such as an ultra-fine optical fiber cable is round and thin.

Therefore, in view of the above-mentioned problems, the present invention does not cause the application of an external force such as a bending moment to a thin wire to cause the tension in a tensile test to occur or to cut the thin wire. A thin wire extensometer that can be easily attached to an extensometer even if it has a bending habit, and can reliably measure the elongation of a thin wire using the existing non-contact displacement measurement method, and a thin wire elongation measurement using the same. It is an object to provide a device.

[0010]

Means for Solving the Problems A first method for solving the above problems is described below.
The thin wire extensometer of the present invention has a first rod in which a first fitting groove for fitting a fine wire as a test piece is formed over the entire length in the axial direction, and a cylindrical shape which is thicker than the first rod. A second rod in which a second fitting groove for fitting the fine wire is formed over the entire length in the axial direction, and a part of the first rod is inserted into the second rod, The whole is made expandable and contractible in the axial direction, and a part of the first fitting groove and a part of the second fitting groove are overlapped with each other to make these grooves straight, and the entire length of these grooves is reduced. A fine wire attaching tool configured to fit the fine wire across, a first fine wire fixing means for fixing the fine wire to the first rod at a first gauge point position, and a second gauge mark Second fine wire fixing means for fixing to the second rod at the position. Characterized in that it comprises Te.

The thin wire extensometer of the second invention is the thin wire extensometer of the first invention, wherein the first and second thin wire fixing means are fitted in a first fixing groove formed in the first rod. A first claw that engages with the first rod to fix the thin wire against the first rod by the first claw;
And a second claw that fits into a second fixing groove formed in the second rod, and the thin wire is pressed against the second rod by the second claw. It is a second clip jig to be fixed.

The thin wire extensometer according to a third invention is the thin wire extensometer according to the first or second invention, wherein a detent pin is fixed to one of the first rod and the second rod, and the other is fixed to the other. By fixing the detent, by inserting the detent pin movably in the axial direction into the hole of the detent,
The first rod and the second rod are configured to prevent relative rotation around an axis.

Further, the thin wire extensometer according to the fourth invention is the thin wire extensometer according to the first, second or third invention, wherein a fixing screw for preventing the first rod and the second rod from expanding and contracting is provided. It is characterized by.

A thin wire elongation measuring device according to a fifth aspect of the present invention is characterized in that the thin wire elongation meter according to the first, second, third, or fourth aspect of the present invention further comprises: First non-contact type displacement measuring means for measuring the amount of displacement of the first rod of the fine wire extensometer displaced in a non-contact manner;
When the fine wire is pulled in the axial direction, the displacement amount of the second rod of the fine wire extensometer that is displaced in the axial direction with the elongation of the fine wire is measured by a non-contact type non-contact type displacement measuring means. It is characterized by having.

The thin wire elongation measuring device according to a sixth invention is the thin wire elongation measuring device according to the fifth invention, wherein
The non-contact type displacement measuring means includes: a first laser light source and a first laser light receiver opposed to each other with an end of the first rod interposed therebetween; The end of the rod and the vicinity thereof are irradiated with a laser beam, and the laser beam is received by the first laser receiver and the width of the laser beam is measured to measure the displacement of the first rod. A first non-contact type displacement measuring device, and a second laser light source and a second laser light receiver opposed to each other with an end of the second rod interposed therebetween; A laser beam is applied to the end of the second rod and the vicinity thereof, and the laser beam is received by the second laser receiver to measure the width of the laser beam. And a second non-contact displacement measuring device for measuring displacement. That.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a cross-sectional view showing the configuration of a fine wire extensometer according to an embodiment of the present invention, FIG. 2A is a cross-sectional view taken along the line AA of FIG. 1, and FIG. 2A is a cross-sectional view showing a first rod extracted from FIG. 2A, FIG. 2C is a cross-sectional view showing a second rod extracted from FIG. 2A, and FIG.
FIG. 3B is a cross-sectional view taken along line CC of FIG. 1.

FIG. 4A is an explanatory view showing a state in which the claws of the clip jig are fitted into the fixing grooves of the first rod, and FIG. FIG. 5 is an explanatory view showing a state in which the rod is fitted into the fixing groove of the rod, FIG. 5 is an explanatory view showing a state in which both ends of the thin line are fixed by the fine end fixing tool,
FIG. 6 is an explanatory diagram showing the overall configuration of the thin wire elongation measuring device and the principle of measurement by the thin wire extensometer, and FIG. 7 is a graph showing the results of a tensile test of the thin wire.

As shown in FIGS. 1 and 2, a fine wire extensometer 2
Numeral 0 is provided with a first rod 21, a second rod 22, a fixing screw 23, a rotation stopping pin 24, a rotation stopping stand 26, and a clip jig 30.

The rod 21 has a cylindrical shape, and a fitting groove 28a for fitting the fine wire 1 is formed on the outer periphery thereof over the entire length in the axial direction (X-axis direction). The fitting groove 28a has a V-shaped cross section and reaches the axis of the rod 21. The distance between the fitting groove 28a and the axis decreases toward the axis. The rod 22 has a cylindrical shape that is thicker than the rod 21, and a fitting groove 28 b for fitting the fine wire 1 is formed on the outer periphery thereof over the entire length in the X-axis direction.
The fitting groove 28b also has a V-shaped cross section and reaches the axis of the rod 22, and the gap decreases toward the axis.

A part of the rod 21 as the inner cylinder is inserted into the rod 22 as the outer cylinder. This allows
The entire rods 21 and 22 can be extended and contracted in the X-axis direction, and a part of the fitting groove 28a and a part of the fitting groove 28b overlap each other to make these grooves 28a and 28b straight, and these grooves 28a , 28b to fit the thin wire 1 over the entire length. Thus, a thin wire attachment for attaching the thin wire 1 is configured. The thin wire attachment is lightweight, that is, the components such as the rods 21 and 22 are made of a lightweight material.

An L-shaped detent pin 24 is fixed to the outer peripheral surface of the rod 21, and a detent table 26 is fixed to the outer peripheral surface of the rod 22. And the rotation stop pin 24
Is inserted into a hole 26a formed in the rotation stopper 26 along the X-axis direction. As a result, the detent pin 24 and the detent 26 are movable in the X-axis direction, but are prevented from moving relative to each other in a direction perpendicular to the X-axis direction. Therefore, the detent pin 2
4 and the rotation stop 26 prevent the rods 21 and 22 from relatively rotating around the X axis without hindering expansion and contraction in the X axis direction.

The fixing screw 23 is provided on the rotation stopper 26 and is screwed into the rotation stopper 26 and the rod 22, and the tip of the fixing screw 23 contacts the outer peripheral surface of the rod 22.
The rods 21 and 22 are prevented from expanding and contracting.

The thin wire 1 is fixed to the rod 21 at the first gauge point position by the clip jig 30 and
It is fixed to the rod 22 at the second gauge point position by another clip jig 30. As shown in FIG. 3, these clip jigs 30 have the same configuration, and are made of a lightweight and elastic thin material.

More specifically, a clip knob 31a and a clip knob 31b are fixed to both ends of a U-shaped spring 34, respectively.
a and 31b are urged in such a direction that their tip sides approach each other. A wedge-shaped claw 32 is provided at the tip of the clip knob 31b. The distal end of the clip knob 31a is curved along the outer peripheral surfaces of the rods 21 and 22. On the other hand, a fixing groove 33a having a V-shape in side view is formed at an end of the rod 21, and a fixing groove 33b having a V-shape in side view is also formed at an end of the rod 22. These fixing grooves 33a and 33b reach the axis of the rods 21 and 22.

Accordingly, the clip jig 30 is provided as shown in FIG.
3 (b), the clip knobs 31a, 31b are expanded against the spring force of the spring 34 as shown by the dashed line, and then the rods 21, 21 are shown as solid lines in FIGS. 3 (a) and 3 (b).
2 is attached to each end. At this time, the tip side of the clip knob 31a contacts the outer peripheral surfaces of the rods 21 and 22, and the claws 32 of the clip knob 31b
The fine wire 1 is pressed against the rods 21 and 22 by fitting into the fixing grooves 33a and 33b of the first and second fixing grooves 33a and 33b. Note that the claw 32 is fixed to the fixing groove 3.
The state when fitting to 3a, 33b is as shown in FIG.

Thus, the thin line 1 is fixed to the rods 21 and 22 at the reference points. At this time, thin line 1
Is the distance L between the fixed groove 33a and the fixed groove 33b, and the total length of the rods 21 and 22 is equal to the end 2 of the rod 21.
A distance L ₁ to the end 27b of the rod 22 from 7a.

As shown in FIG. 5, the thin wire 1 is installed with both ends extended to the outside of the extensometer 20 (rods 21 and 22). Then, both ends of the fine wire 1 are fixed by the fine wire end fixing tool 50, respectively. The tensile test of the fine wire 1 is performed by pulling the fine wire end fixture 50 with a tensile tester.

As shown in FIG. 6, when the distance between the reference points of the fine wire 1 is extended by ΔL to L + ΔL by pulling the fine wire 1, the rods 21 and 22 are extended with the extension of the fine wire 1, and the rods 21 and 22 are extended. The total length of 21 and 22 is L1 + ΔL.
That is, the elongation ΔL of the thin wire 1 is the same as the displacement generated at both ends 27a and 27b of the rods 21 and 22. Therefore,
Displacement ΔL of both ends 27a and 27b of the rods 21 and 22
Is measured, the elongation ΔL of the fine wire 1 can be measured.

Therefore, both ends 27a of the rods 21 and 22 are
The displacement of 27b is measured by a displacement measuring device. In this case, in order to accurately maintain the tension applied to the fine wire 1, it is desirable to measure the displacement without contacting the fine wire 1 and the extensometer 20. For this reason, in the present embodiment, the displacement measurement of both ends 27a and 27b of the rods 21 and 22 is performed by a non-contact displacement measurement device using a laser beam as shown in FIG.

Specifically, as shown in FIG.
The laser light source 41a and the laser light receiver 42a are disposed opposite to each other with the end of the rod 21 interposed therebetween, and the end of the rod 21 and the vicinity thereof are irradiated with the laser beam 43a from the laser light source 41a,
The laser beam 43a is received by the laser receiver 42a. At this time, the width of the laser beam emitted from the laser light source 41a is L ₂ , but a part thereof is blocked by the end of the rod 21, so that the width of the laser beam received by the laser receiver 42a is L 2. ₃ (<L ₂ ). Then, the width L ₃ of the laser beam changes according to the displacement of the end 27a of the rod 21. Thus, by measuring the width L ₃ of the laser beam at the laser receiver 42a, it is possible to measure the displacement of the end 27a of the rod 21.

Similarly, the laser light source 41b and the laser light receiver 42b are arranged opposite to each other with the end of the rod 22 interposed therebetween, and the end of the rod 22 and the vicinity thereof are irradiated with the laser beam 43b from the laser light source 41b. , This laser beam 43b
Is received by the laser receiver 42b. In this case, the width of the laser beam emitted from the laser light source 41b is L _2, by the part is blocked in the end of the rod 22, the width of the laser beam received by the laser receiver 42b L ₃ (<L ₂ ). And the width L of this laser beam
₃ changes according to the displacement of the end 27b of the rod 22.
Thus, by measuring the width L ₃ of the laser beam at the laser receiver 42b, it is possible to measure the displacement of the end 27b of the rod 22.

Next, the procedure of a tensile test of the fine wire 1 using the fine wire extensometer 20 will be described (see FIGS. 1 to 6).

First, the distance between the fixing grooves 33a and 33b is set to a predetermined gauge length L by appropriately expanding and contracting the rods 21 and 22, and the rods 21 and 22 are fixed by the fixing screws 23 while maintaining the gauge length L. To prevent these expansions and contractions.

In this state, the fine wire 1 is fitted into the fitting grooves 28a and 28b of the rods 21 and 22, and the clip jig 30
The thin wire 1 is fixed to the rod 21 at the first reference point position (the position of the fixing groove 33a), and the thin wire 1 is fixed to the second reference point position (the fixing groove 33) by another clip jig 30.
(Position b)). At this time,
Since the rods 21 and 22 are fixed by the fixing screw 23, they do not expand and contract.

Subsequently, the fine wire end fixture 5 is attached to both ends of the fine wire 1.
0 is attached. When the attachment of the fine wire 1 to the fine wire extensometer 20 and the attachment of the fine wire end fixing tool 50 to the end of the fine wire 1 are completed, the fixing screw 23 is loosened to allow the rods 21 and 22 to expand and contract, and the fine wire 1 is illustrated. Not attached to the tensile tester. The gauge length L of the thin line 1 before the tension is
This is the distance L between the fixed grooves 33a and 33b.

Next, the fine wire end fixture 50 was tested by a tensile tester.
Is tensioned in the X-axis direction to apply a tension in the X-axis direction to the thin wire 1. As a result, the thin wire 1 elongates, and the rods 21 and 22 also elongate with the elongation of the fine wire 1, and
Both ends 27a of the first and second 22 are displaced in the X-axis direction.
That is, since the rods 21 and 22 are fixed at one point (the fixing grooves 33a and 33b) with respect to the thin wire 1 and can expand and contract with each other in the X-axis direction, the extension of the thin wire 1 is the same as that of the entire rod. Is reflected in At this time,
The rods 21 and 22 are guided in the X-axis direction by the operation of the rotation stop pins 23 and the rotation stop stand 26,
Does not relatively rotate about the X axis.

The displacement of the end 27a of the rod 21 is measured using the laser light source 41a and the laser light receiver 42a, and the displacement of the end 27b of the rod 22 is measured.
And the laser receiver 42b. Thus,
The elongation ΔL of the fine wire 1 can be measured.

FIG. 7 shows an example of the result of a tensile test of a thin wire. In the figure, the horizontal axis is the strain (elongation) generated in the fine line.
And the vertical axis represents stress. In the tensile test, an optical fiber (diameter: 0.25 mm) coated with an ultraviolet curable resin having a total length of 120 mm was used as a thin wire (test piece), and the optical fiber was pulled at a constant speed by a tensile tester. By applying a load (tension). The gauge length at this time is 50 mm.

The stress-strain diagram of FIG. 7 shows linearity even under a small load. This result indicates that the bending or moment hardly affects the test piece, and the optical fiber (test piece)
This shows that the attachment of the extensometer to the extensometer, the centering, and the maintenance of the gauge length of the extensometer were successfully performed.

As described above, according to the present embodiment, the fine wire 1 is fitted over the entire length of the fitting grooves 28a and 28b of the rods 21 and 22 and fixed. There is no danger that the test tension will be twisted or the thin wire will be broken. Moreover, since the thin wire 1 can be fixed to the rods 21 and 22 by the clip jig 30 after the thin wire 1 is fitted into the elongated fitting grooves 28a and 28b, even if the thin wire 1 has a bending habit, the thin wire 1 can be easily formed.
Can be attached to the fine wire extensometer 20.

Further, in the tensile test, since the elongation of the fine wire 1 is measured by measuring the displacement of the rods 21 and 22 instead of directly measuring the elongation of the fine wire itself, an existing non-contact type displacement measuring device is used. Fine wire 1 easily
Can be measured. That is, the rods 21 and
2 is sufficiently thicker than the thin wire 1, so that both ends 27a, 2
The existing method of measuring the displacement of the object without contact can be applied to the displacement detection of 7b, and as a result, the elongation measurement of the thin wire 1 can be performed without contact.

The clip jig 30 is provided with fixing grooves 33a,
33b, the thin wire 1 is pressed against the rods 21 and 22 by the nail 32.
The structure is simple, and the fine wire 1 is securely connected to the rod 21,
22.

Further, the rotation stop pin 24 is fixed to the rod 21, the rotation stop table 26 is fixed to the rod 22, and the rotation stop pin 24 is axially movably inserted into the hole 26 a of the rotation stop table 26. Is configured to prevent the rods 21 and 22 from relatively rotating around the X-axis, so that the rods 21 and 22 relatively rotate around the X-axis in the tensile test and wrap the tension in the tensile test. Can be reliably prevented.

Further, when the thin wire 1 is attached, the expansion and contraction of the rods 21 and 22 can be prevented by the fixing screw 23, so that the thin wire 1 can be easily attached to the rods 21 and 22, and before the tensile test. X for thin line 1
Can be installed without applying axial force.

In the fine wire elongation measuring device using the fine wire extensometer 20 as described above, the accurate measurement of the fine wire 1 can be easily performed by the non-contact displacement measuring device.

In the above description, the laser light sources 41a and 41b and the laser light receiver 42 are used as non-contact displacement measuring devices.
a, 42b were used, but the present invention is not limited to this.
As a device for performing the displacement of a and 27b in a non-contact manner, for example, a device using sound, electromagnetic waves, or the like in addition to light may be used. Further, since the rods 21 and 22 are sufficiently thicker than the fine wire 1,
Displacement measurement is performed by capturing images of the rods 21 and 22 with a camera or the like, and the movement amount of both ends 27a and 27b of the rods 21 and 22 by a feed amount measurement device that tracks the movement of a spectral pattern generated by laser beam irradiation ( (Amount of displacement) may be detected.

The clip jig 30 is provided with a spring 34.
However, the present invention is not necessarily limited to this. For example, a clip jig is manufactured using a shape memory alloy instead of the spring 34, and the force by which the shape memory alloy returns to a predetermined shape is obtained. Fine wires 1 are rods 21 and 22
May be fixed.

Further, in the above, the rods 21 and 22 are prevented from relatively rotating around the X axis by the rotation stopping pin 24 and the rotation stopping stand 26, but the invention is not necessarily limited to this. For example, when the outer diameter of the rod 21 and the inner diameter of the rod 22 are substantially equal and the gap between them is small,
Even if the rods 21 and 22 relatively rotate about the X axis, the rods 21 and 22 are inserted into the fitting groove 28 a of the rod 21 and the rod 2.
It can be restricted at the overlapping portion with the second fitting groove 28b.

[0050]

As described above in detail with the embodiment, according to the fine wire extensometer of the first invention, the fine wire is connected to the first wire.
Since the rod and the second rod are fitted and fixed over the entire length in the groove, the bending moment is applied to the thin wire, and there is no danger that the tension in the tension test will be generated or the thin wire will be broken. Moreover, since the fine wire can be fixed to the first rod and the second rod by the first fine wire fixing means and the first fine wire fixing means after being fitted into the fitting groove, the fine wire has a bending tendency. Even if it is attached, the fine wire can be easily attached to the fine wire extensometer.

Further, in the tensile test, the elongation of the fine wire itself is not directly measured, but the first rod and the second rod are not directly measured.
Since the elongation of the fine wire is measured by measuring the displacement of the rod, the elongation of the fine wire can be easily measured even with an existing non-contact type displacement measuring device. That is, since the first and second rods are sufficiently thicker than the thin wire, the existing method of measuring the displacement of the object in a non-contact manner can be applied to the detection of the displacement at both ends thereof. The measurement can be performed without contact.

Further, according to the fine wire extensometer of the second invention, the first and second clip jigs have claws which fit into the fixing grooves, and the fine wires are connected to the first rod and the second rod by the claws. Since the configuration is such that the wire is pressed against the rod, the configuration is simple and the fine wire can be securely fixed to the first rod and the second rod.

Further, according to the thin wire extensometer of the third invention, the detent pin is fixed to one of the first rod and the second rod, and the detent is fixed to the other. The first rod and the second rod are inserted into the holes of the rotation stop movably in the axial direction so as to prevent the first rod and the second rod from rotating relatively around the axis. It is possible to reliably prevent the rod and the second rod from rotating relative to each other around the axis and thereby squeezing the tension in the tensile test.

Further, according to the thin wire extensometer of the fourth invention, when attaching the thin wire, the first and second rods can be prevented from expanding and contracting by the fixing screw. And can be attached without applying an axial force to the fine wire before the tensile test.

In the fine wire elongation measuring device according to the fifth or sixth aspect of the present invention, since the thin wire extensometer according to the first, second, third or fourth aspect of the invention is used, a non-contact type displacement with respect to the fine wire is used. Accurate elongation measurement can be easily performed by the measuring device.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a configuration of a fine wire extensometer according to an embodiment of the present invention.

2A is a cross-sectional view taken along line AA of FIG. 1, FIG. 2B is a cross-sectional view showing a first rod extracted from FIG. 1A, and FIG.
FIG. 4 is a cross-sectional view showing a second rod extracted from FIG.

3A is a sectional view taken along line BB of FIG. 1, and FIG. 3B is a sectional view taken along line CC of FIG.

FIG. 4A is an explanatory view showing a state in which a claw of a clip jig is fitted into a fixing groove of a first rod, and FIG. 4B is a diagram illustrating a state in which a claw of the clip jig is fixed to a fixing groove of a second rod. FIG. 4 is an explanatory diagram showing a state when fitting is performed.

FIG. 5 is an explanatory view showing a state where both ends of a thin wire are fixed by a thin wire end fixing tool.

FIG. 6 is an explanatory diagram showing an overall configuration of a thin wire elongation measuring device and a principle of measurement by the thin wire extensometer.

FIG. 7 is a graph showing a result of a tensile test of a thin line.

FIG. 8 is a configuration diagram showing an example of a conventional contact-type elongation measuring device.

FIG. 9 is an explanatory diagram of a bending moment generated in a tensile test by the contact-type elongation measuring device.

FIG. 10 is an explanatory diagram of a shear force generated in a tensile test by the contact-type elongation measuring device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fine wire (test piece) 20 Fine wire extensometer 21 Rod (inner cylinder) 22 Rod (outer cylinder) 23 Fixing screw 24 Detent pin 26 Detent pin 26a Detent hole 27a, 27b Rod end 28a, 28b Fitting groove REFERENCE SIGNS LIST 30 clip jig 31 a, 31 b clip knob 32 claw 33 fixing groove (V-shaped groove) 34 spring 41 a, 41 b laser light source 42 a, 42 b laser light receiver 43 a, 43 b laser beam

Continued on the front page. (72) Inventor Noboru Arase 5-4-2, Tobio, Atsugi-shi, Kanagawa Prefecture Inside Testronics Co., Ltd. F-term (reference) 2F062 AA02 AA99 BB02 BC01 BC80 CC08 CC20 CC22 CC30 EE03 EE09 EE63 FF13 FF25 FG08 GG58 GG65 GG72 2F065 AA02 AA07 AA09 AA65 BB12 CC23 DD11 DD16 FF02 FF56 GG04 HH02 JJ04 JJ04 GG04 HH02 JJ CC09 DD25 DD30 GG04 GG06 GG07 GG09 GG18 GG45 GG63 HH09 JJ13 JJ25 MM02 MM23 MM34 PP02 RR03 2G061 AA01 AB01 EA02 EB07

Claims (6)

[Claims] 1. A first method for fitting a thin wire as a test piece.
A first rod having a fitting groove formed over the entire length in the axial direction, and a second fitting groove having a cylindrical shape larger than the first rod and for fitting the fine wire, extending along the entire length in the axial direction. And a second rod formed by inserting a part of the first rod into the second rod so that the entire rod can expand and contract in the axial direction. A part and a part of the second fitting groove are overlapped to form these grooves in a straight line, and the fine wire attaching tool is configured to fit the fine wire over the entire length of these grooves; A first thin line fixing means for fixing the thin line to the first rod at a first gauge point position; and a second fine line fixing means for fixing the thin line to the second rod at a second gauge point position. A thin wire extensometer characterized by the following. 2. The fine wire extensometer according to claim 1, wherein the first and second fine wire fixing means include a first claw fitted in a first fixing groove formed in the first rod. A first clip jig for fixing the thin wire by pressing the fine wire against the first rod by the first claw; and a second jig fitted to a second fixing groove formed in the second rod. And a second clip jig having two claws and fixing the thin wire by pressing the thin wire against the second rod with the second claw. 3. The thin wire extensometer according to claim 1, wherein a rotation stop pin is fixed to one of the first rod and the second rod, and a rotation stop table is fixed to the other. The first pin and the second rod are prevented from relatively rotating around the axis by inserting the detent pin movably in the axial direction into the hole of the detent table. A thin wire extensometer characterized by the following. 4. The thin wire extensometer according to claim 1, wherein a fixing screw for preventing expansion and contraction of the first rod and the second rod is provided. 5. The thin wire extensometer according to claim 1, 2, 3, or 4, wherein said thin wire extensometer is displaced in the axial direction along with the elongation of said thin wire when said thin wire is pulled in the axial direction. A first non-contact type displacement measuring means for measuring a displacement amount of a rod in a non-contact manner; A thin wire elongation measuring device comprising: a second non-contact displacement measuring means for measuring a displacement of the rod in a non-contact manner. 6. The thin wire elongation measuring device according to claim 5, wherein the first and second non-contact displacement measuring means include a first laser light source with an end of the first rod interposed therebetween. And a first laser light receiver are disposed opposite to each other, and a laser beam is emitted from the first laser light source to the end of the first rod and the vicinity thereof, and the laser light is applied to the first laser light receiver. By measuring the width of the laser beam by receiving at
A first non-contact displacement measuring device for measuring the displacement of the first rod; and a second laser light source and a second laser light receiver opposed to each other with an end of the second rod interposed therebetween. Then, the end of the second rod and its vicinity are irradiated with a laser beam from the second laser light source, and the laser beam is received by the second laser light receiver to measure the width of the laser beam. Than that
And a second non-contact displacement measuring device for measuring the displacement of the second rod.