JPS5847375Y2 - Extensometer verification device - Google Patents

Description

[Detailed description of the invention] This invention relates to an extensometer, particularly an automatic extensometer verification device.

Generally, an extensometer is an instrument that is attached to a tensile testing machine and measures the elongation between the gauge points of the test piece during the test by enlarging it at a high magnification. For example, convert the movement of A method of recording in formulas is used.

Extensometers with a gage distance of about 5Qmm and an elongation measurement range of up to about 20mm are usually attached directly to the test piece, and with such small detachable extensometers, the calibration work is difficult. This can be easily carried out on a measurement surface using a verification device incorporating a micrometer head (see Fig. 10).

Further, in order to perform verification in accordance with the displacement direction of the measuring lever of the extensometer, it is sufficient to change the holding posture of the extensometer to the verification device.

As shown in Fig. 10, the above-mentioned testing device is for a small detachable extensometer 3, and consists of a fixed spindle F attached to the upper part of a stand placed on a surface plate T, and a fixed spindle F attached to the lower part thereof. Movable spindle S of micrometer M
The extensometer 3 is mounted by holding its upper measuring lever 4 and its lower measuring lever 4', respectively, and by turning the knob of the micrometer M in the direction of the arrow, for example, the extensometer 3 is attached to the movable spindle. This spindle S is moved by a predetermined amount in the downward direction shown by the arrow.
The extensometer 3 is verified by comparing the read value on the micrometer M of the amount of movement of the extensometer 3 with the displayed value of the amount of elongation on the extensometer 3 due to the movement of the lower measuring lever 4' that moves together with the spindle S. It is something that exists.

However, with automatic extensometers, most of the operations, including the attachment and detachment of the measurement lever to the test piece, are performed by push-button operation or automatically when measuring the elongation between gauge points during the tensile test of the test piece described above. This is a high-efficiency, labor-saving device that automatically performs operations based on sequence commands, and compared to the conventional extensometer described above,
It is large in size and is installed integrally with the tensile testing machine.
It is difficult to remove it from the testing machine body and move it onto the measurement surface each time a test is performed.

Therefore, it is desirable that such an automatic extensometer verification device be capable of performing calibration work while attached to an extensometer testing machine.

Fig. 1 is a front view of a typical hydraulic tensile testing machine equipped with an automatic extensometer, and Fig. 2 is a side view thereof.

In this type of testing machine, a load is applied to the test piece 2 by raising the upper chuck frame 1.

Therefore, the measuring levers 4 and 4' of the automatic extensometer 3 are also moved upward, and the elongation of the piece 2 is detected and measured in an upward tension type.

Figure 3 is a side view of the main parts of the extensometer, with the upper measuring lever 4
, the lower measurement lever 4' is shown holding the upper and lower gauge points of the test piece 2 with the needle-like protrusions on the left end thereof.

FIG. 4 is a front view of an automatic extensometer installed in a typical screw type tensile testing machine, FIG. 5 is a side view thereof, and FIG. 6 is a side view of the main part of the extensometer.

In this type of testing machine, a load is applied to the test piece 2 by lowering the lower chuck frame 5, and the measuring levers 4, 4' of the automatic extensometer 3 are accordingly moved.
also moves downward, and the elongation of specimen 2 as a downward tensile type is
Detected and measured.

Note that the measuring levers 4 and 4' usually do not move upward or downward in parallel; for example, in an extensometer attached to an upward tension type testing machine, the upward movement of the upper measuring lever 4 is the same as that of the lower measuring lever. Hail is bigger than that.

As a result of the above, in the extensometer verification device, no matter which of the two types of tensile testing machines, upward tension type and downward tension type, are installed, the measurement lever of each extensometer can be adjusted. It is necessary to carry out calibration work according to the direction of displacement.

In addition, the automatic extensometer is designed to measure a wide range of elongation, from the minute elongation within the elastic range of the material of the test piece to the elongation just before the test piece breaks, so it is suitable as an extensometer verification device. , it must be able to verify the displacement of the extensometer measuring lever over a wide range with high accuracy.

By the way, all of the conventionally provided extensometer verification devices are the same or slightly different from the one shown in FIG. The extensometer 3 should be able to be calibrated in a state in which No device has been provided that satisfies all of the three requirements of being able to perform calibration work and verify the displacement of the extensometer 3 over a wide range with high precision.

This invention aims to provide an extensometer, especially an automatic extensometer, verification device that satisfies the three requirements mentioned above, which cannot be met or is difficult with conventional extensometer verification devices. A fixed block and a movable block each having ears for attaching each of a pair of measuring levers to be attached to a test piece of an extensometer attached to a testing machine are mounted between bases fixed vertically symmetrically to both ends of a column. The former fixed block is fixedly engaged with the column, and the latter movable block is slidably engaged with the column, and further includes a moving mechanism that moves the moving block relative to the fixed block, and a measuring mechanism that measures the amount of movement thereof. The present invention relates to an extensometer verification device having a vertically symmetrical shape so that it can be fixed to the test piece chuck frame of the testing machine via the base so as to be able to fall vertically.

Hereinafter, the extensometer verification device according to this invention will be explained in detail with reference to the drawings.

Figure 7 is a plan view of this device, and Figure 8 is the X-0-
9 is a longitudinal sectional view taken along the X section and viewed in the direction of the arrow, and FIG. 9 is a similar longitudinal sectional view when the apparatus of FIG. 8 is set upside down.

In the figure, 6.6' is a base, which is connected correctly in parallel through a pair of columns 7, and has a thrust bearing 9 and a radial bearing with a threaded rod 8 attached near the shaft end in the center. 10, and are engaged so as to be rotatable in a fixed position without play in the axial direction.

11 is a rotating plate, which is fixed to both ends of the threaded rod 8;
A hole 12' is provided in which the handle 12 is removably attached.

A fixed block 13 is fixed to the column 7 at a position close to the base 6'.

The fixation is achieved by making a slit 13' reaching the hole in which the column 7 of the fixing block 13 is inserted, tightening the bolt, and narrowing the gap between the slit 13' so that the inner periphery of the hole squeezes the column 7. be done and be done.

The fixed block 13 also has a hole 14 through which the threaded rod 8 is passed.
and a hole 15' through which the magnetic scale 15 freely passes.

Reference numeral 16 denotes a coaxial magnetic head through which a scale for reading the magnetic scale 15 passes, and is attached to one opening of the through hole 15' with its center aligned therewith.

Reference numeral 17 denotes a movable block, which is slidably engaged with the column 7 without play, and has a hole 18 through which the threaded portion of the threaded rod 8 freely passes, and one of its openings has a hole 18 through which the threaded portion of the threaded rod 8 passes freely. 19.19' is contained.

The nut 19 is fixed to the moving block 17, and the nut 19' is rotatably engaged with the moving block 7, but has a torque pin and a coil spring (both not shown) engaged with the torque pin. Through this, the nut 19 is engaged with a preload applied in the axial direction by the elastic force of the coil spring.

Therefore, since the moving block 17 is threadedly connected to the threaded portion of the threaded rod 18 without play in the axial direction, the moving block 17 is attached to the threaded rod 18 without buckling even when the threaded rod 18 is rotated in either the left or right direction. This means that it can be moved.

In addition, the moving block 17 has a hole 15' through which the magnetic scale 15 freely passes, similar to the fixed block 13, and one opening has a scale fixing hole 15' for fixing the magnetic scale 15 at its end. A fixture 20 is attached.

Reference numeral 21 designates ears for attaching the tips of the upper and lower measuring levers 4, 4' of the automatic extensometer 3.

The base 6.6' has an insertion hole 2 for the fixing bolt.
A magnetic scale 15 is provided on the base 6'.
A through hole 15' is provided to avoid interference with the.

Next, operation 1 in this apparatus will be explained.

First, I will talk about the verification of the automatic extensometer installed in the upward tension type testing machine.

For example, move the upper chuck frame 1 of the testing machine shown in FIGS. While using and fixing the measuring lever 4 of the extensometer 3
, 4' are attached to the ears 21 of the moving block 17 and fixed block 13, respectively.

Then, the scale position of the magnetic scale 15 at that time is read by the output signal from the magnetic head 16, and at the same time,
The zero point of the measuring levers 4, 4' is set using the extensometer 3.

Then, the rotating plate 11 is manually rotated clockwise using the handle 12 when viewed from above.

In this case, the threaded portion of the threaded rod 8 will be described as a right-handed thread.

The moving block 17 has a nut 19 fixed thereto.
, are engaged with the threaded portion of the threaded rod 8 without any backlash through the nut 19', which is connected to the nut 19 by the aforementioned torque pin, so that the threaded portion of the threaded rod 8 can be rotated without causing any delay. , moved upwards.

As a result of this movement, the measuring lever 4 also moves upward at the same time.

On the other hand, since the magnetic scale 15 is fixed at its upper end to the moving block 17 via the scale fixture 20, the scale 15 is also fixed to the fixed block 13 at the same time by the same length as the lifting amount of the moving block 17. The magnetic head 16 passes between the magnetic heads 16.

Therefore, if the rotating plate 11 is rotated by the handle 12 an arbitrary number of times and then stopped, the amount of movement of the movable block 17 relative to the fixed block 13 up to that point will depend on the scale position of the magnetic scale 15 at that point. ,
Accurate information can be determined by reading the signal output from the magnetic head 16 and the difference between the reading at the start of pulling as described above.

In this case, the measuring lever 4 is pulled up by the same amount as the moving amount of the moving block 17 with respect to the measuring lever 4', but the amount of lifting can be known from the reading record or display of the extensometer 3 itself. .

Therefore, the reading value indicating the amount by which the moving block 17 is pulled up by the output signal from the magnetic head 16 of this device is compared with the reading value indicating the amount by which the measuring lever 4 is pulled up by the extensometer 3. This allows the extensometer 3 to be calibrated.

Repeat the above operation until the elongation measurement range of extensometer 3 is reached.
By sequentially repeating the test, the extensometer verification work is performed under approximately the same conditions as when performing a tensile test with test piece 2 set in an upward tension type testing machine, with extensometer 3 installed in the testing machine. be able to.

When a load is applied to specimen 2 using an upward tension method,
Together with the upper measuring lever 4, the lower measuring lever 4' is also moved upwards, although to a much lesser extent.

By the way, in this device described above, the verification work is performed with the lower measuring lever 4' fixed, and the movement of the measuring levers 4, 4' during the tensile test cannot be completely reproduced. do not have.

However, the reading of the elongation of specimen 2 by extensometer 3 is
Since this is done by detecting the difference in the amount of movement of both the upper measuring lever 4 and the lower measuring lever 4', the moving speed of the lower measuring lever 4' during the tensile test is extremely slow and zero. It can be said that this reproduces a case that can be approximated as .

In addition, when this device is used to verify the automatic extensometer 3 installed in a downward tensile type testing machine, as shown in FIG.
For example, move the lower chuck frame 5 of the testing machine shown in FIG. 4 to an appropriate position, fix it there, and
By replacing the handle 12 with the rotary plate 11 on the base 6' side and rotating the handle 12 counterclockwise when viewed from above, the same operation as in the case of the extensometer 3 of the above-mentioned upward tension type testing machine is performed. It is possible to perform verification work on the extensometer 3 when measurement is performed using the downward tension method.

In this device, both the play between the moving block 17 and the column 7 and the axial play of the threaded rod 8 with respect to the base 6.6' are minimized as much as possible, and the moving block 8 is smoothly moved by the column 7. The accuracy of this device is on the scale 15 insofar as it is guided and moved by the rotational feed of the threaded rod 8 at 9.9', which engages the threaded part of the threaded rod 8 without breaking. It depends on the accuracy of .16.

The accuracy of the scale depends on (a) the graduation accuracy and stability of the magnetic scale 15, (b) the quality of the output signal of the reading head, that is, the magnetic head 16, and (c) the quality of the mechanism for attaching the scale 15 and head 16. However, using commercially available products with guaranteed quality, special attention should be paid to the installation of the scale 15 and head 16, and although not shown, the exposed portion of the magnetic scale 15 should be protected against intrusion of dust, etc. If a telescoping dust sleeve is applied, the elongation can be measured from 1 to 2 over the normal measurement range.
It is possible to maintain accuracy on the order of μ.

As is clear from the above explanation, compared to conventional devices, the extensometer verification device according to the present invention can be used to verify extensometers, especially automatic extensometers, by moving the measuring lever upward. By moving the measuring lever in the downward direction, it is possible to carry out verification work while the extensometer is installed in the tensile testing machine according to the displacement direction of the lever. Since it is equipped with a detection mechanism, it is possible to quickly and accurately verify the displacement of the extensometer measurement lever over a wide range, from minute elongation within the elastic range of the test piece to elongation just before it breaks. be.

[Brief explanation of drawings]

Figure 1 is an external front view of an automatic extensometer installed in a hydraulic tensile testing machine, Figure 2 is a side view of it, Figure 3 is a side view of the main parts of the extensometer, and Figure 4 is a screw type tensile tester. A front view of the external appearance of an automatic extensometer installed in the testing machine, Fig. 5 is a side view thereof, Fig. 6 is an external side view of the main parts of the extensometer, and Fig. 7 is a plan view of the extensometer verification device according to this invention. , Figure 8 is X-0 in Figure 7.
-A longitudinal sectional view taken along the -X cross section and seen in the direction of the arrow; Fig. 9 is a longitudinal sectional view similar to Fig. 8 with the device in Fig. 8 set upside down, and Fig. 10 is a longitudinal sectional view of the conventional device. FIG. 2 is an external side view showing an example of an extensometer verification device. 1... Upper chuck frame, 2... Test piece, 3... Automatic extensometer, 4... Upper measuring lever, 4'...・Lower measurement lever, 5...
・・Lower chuck frame, 6, 6′・・・・Base, 7
...Column, 8...Threaded rod, 9...
... Thrust bearing, 10... Radial bearing,
11... Rotating plate, 12... Handle, 13
...Fixed block, 15...Magnetic scale, 16...Magnetic head, 17...
Moving block, 19.19'...Natsuto, 20
...Scale fixing tool, 21...Ear part for mounting the measurement lever, 22...Fixing bolt hole.

Claims (1)

[Scope of utility model registration request] 1. A fixed block and a movable block each having ears for attaching each of a pair of measurement levers to be attached to a test piece of an extensometer attached to a tensile testing machine are installed between bases fixed vertically symmetrically to both ends of a column. The former fixed block is fixedly engaged with the column, and the latter moving block is slidably engaged with the column, and includes a moving mechanism that moves the moving block relative to the fixed block, and a measuring mechanism that measures the amount of movement thereof, Furthermore, the extensometer verification device has a vertically symmetrical shape so that it can be fixed to the test specimen chuck frame of the testing machine via the base so as to be able to fall vertically. 2. A moving mechanism for moving the movable block relative to the fixed block includes a screw rod rotatably engaged with each of the upper and lower bases, two nuts fixed to the movable block and screwed into the screw rods, and the screw rod. The extensometer verification device according to claim 1, which is comprised of a rotary handle that can be selectively and detachably engaged with both ends of the rod. 3. Utility model registration according to claim 1, wherein the measuring mechanism for measuring the amount of movement of the moving block relative to the fixed block is composed of a magnetic scale fixed to the moving block and a magnetic head fixed to the fixed block. Extensometer verification device.