JPS6118692B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for calibrating the accuracy of extensometers used with materials testing machines.

The conventional method for calibrating an extensometer is to attach a similar test piece and the extensometer to be calibrated to a material testing machine, connect the display output of the extensometer to the material testing machine and connect it to a pen recorder, and perform the material test. A dial gauge is installed between the machine's test piece gripping tool or the head that interlocks with it, and one worker operates the load controller while reading the elongation display value to displace the crosshead by a predetermined amount and then stop it, and the other worker A method was used in which a worker reads and records the instructions on a dial gauge attached to a material testing machine, and repeats this process sequentially over the entire stroke range of the extensometer. Such conventional methods consume a lot of work time, require two or more workers, have many opportunities for human errors such as reading errors, and use dial gauges, so for example When calibrating the entire stroke range of ~100mm, it cannot be measured continuously and must be used in conjunction with a block gauge, and the accuracy at that time cannot be increased to more than 1/100mm of the dial gauge. There were a number of shortcomings.

The present invention solves the above-mentioned drawbacks at once, and
The present invention provides a new automatic extensometer calibration device that automatically performs calibration work with high accuracy.

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is an overall configuration diagram of an embodiment of the present invention.

The hardness test pieces 3A and 3B are respectively placed on the fixed stand 1 and movable head 2 of the material testing machine or its hardness testing device.
The arms 5A and 5B of the extensometer 4 to be calibrated are attached to the reference points. On the other hand, a reference detector 6 is placed on a fixed base 1, and a measuring element 7 at the tip thereof is installed so as to be in contact with the movable head 2.
This reference detector 6 is a length-to-electrical conversion device, preferably a length-to-digital signal conversion device, and comprises:
An encoder that uses a long optical grating that moves with the measuring element 7 as a scale and optically reads the moiré fringes that occur between the detection gratings, or a special encoder that uses a scale that records a sine wave of a constant wavelength on a magnetic band and can read even in a stationary state. A type with a structure such as a magnetic grid that uses a magnetic head to convert it into an electric signal is suitable, and a type with a continuous measurement range of 0 to 100 mm and a resolution and accuracy of 1 μm is commercially available, and this is installed vertically on the stand 8. It can be used by supporting it and placing it on a fixed base 1. The electric outputs of the display unit 9 and the reference detector 6 of the elongation 4 are connected to the printer unit 1 by cables 10 and 11, respectively.
Connected to 2.

FIG. 2 shows a block diagram of an electric circuit according to an embodiment of the present invention. The device includes an up-down counter 21 that counts pulse signals, a numeric display 22 that displays the contents of the counter, a setter 23 that uses a digital switch to set the value to be printed out, and the contents of the counter 21 and the setter 23. A comparator 2 that compares and outputs a match detection signal when the two match.
4. Consists of a printer controller 25 and a printer 26, the pulse signal of the reference detector is input to the counter 21, and the output of the counter 21 and the output of the extensometer unit are input to the printer controller 25 as print signals. ing.

Such a printing unit is housed in a portable container 30, as shown in FIG. A switch 32, a power cord connection connector 33, a reference detector connection connector 34, an extensometer output connection connector 35, a changeover switch 36 between a test state and a reset state, and the like are provided.

In use, when preparations for measurement are completed, the changeover switch 36 is switched from the reset side to the test side, the digital switch 31 is set to, for example, 000.010, and the object to be measured is displaced. When the reference detector is displaced by 10 μm, the comparator 24 detects a match between the set value and the counted value and sends a print command to the printer controller 25, so the printer 26 calculates the displacement amount of the reference detector at that time, 000.010, and the extensometer. For example, print 000.009 in parallel.

Next, set the digital switch 31 to
If the measurement progresses to 000.020 and the object to be measured is further displaced, the printer 26 automatically prints both numerical values in parallel when the displacement amount of the reference detector reaches 000.020.
Calibration is performed sequentially by repeating similar operations. An example of the printing results obtained in this manner is shown in FIG. The displacement amount of the reference detector 6, that is, the true displacement amount of the object to be measured is printed in the left column 41, and the continuation of the extensometer is printed in the right column 42, so the error (μm) can be immediately determined by comparing both values. You can ask for it.

As another embodiment of the present invention, desired calibration data can be obtained by using printing paper on which reference values are printed in advance on the left column and printing only the right column from the printer. Further, both numerical values can be printed simultaneously using two printers.

Furthermore, the setting device of the present invention is composed of a memory and an input key, and all reference values can be set and stored in advance.Furthermore, all reference values can be stored in a perforated card, magnetic card, etc. It can be used detachably.

According to the present invention, measurement accuracy is improved by more than one order of magnitude compared to the conventional dial gauge method. In addition, with the conventional dial gauge method, it was necessary to replace the gauge in the middle of the measurement, which caused errors during replacement, but with the present invention, there is no error.
Continuous measurement of the entire stroke of ~100mm is now possible. Furthermore, with the conventional dial gauge method, the instructions had to be read visually and the movement of the object to be measured had to be stopped at each measurement point, but the present invention uses a displacement-electrical conversion device, so it is continuous. Conventionally, two workers were required, but in the present invention, it is possible to use one or no workers. Further, according to the present invention, a setting device is provided for setting the elongation value to be calibrated, and a means for detecting coincidence between the output of the reference detector and the value set by the setting device (reference value) is provided, and the reference detection When the output of the device matches the set value, the reference value and the extensometer reading are automatically printed at the same time, eliminating the conventional human reading error and making it easier to calculate the extensometer error. It became easier and the reliability of the test improved.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram showing the usage state of the embodiment of the present invention, FIG. 2 is an electric circuit block diagram of the printer unit 12, and FIG. 2 is a diagram showing a front view of the meter display unit and a perspective view of the appearance of the printer unit 12. FIG. FIG. 4 is a diagram showing an example of printing results according to the present invention. 3A, 3B...Fluid test piece, 4...Extensometer, 6
...Reference detector, 9...Extensometer display unit, 1
2...Printer unit.

Claims (1)

[Claims] 1. In a device that calibrates the displayed value of the extensometer by attaching a pseudo test piece and an extensometer to be calibrated to a pair of specimen grips, converts the displacement length between the pair of specimen grips into an electrical signal. a reference detector;
a setting device for setting an elongation value to be calibrated; a coincidence detection means for detecting coincidence between the output of the reference detector and the setting value of the setting device; and the detection of the reference when the detection output of the coincidence detection means is generated. An automatic extensometer calibration device comprising: a recorder for recording the output of the extensometer and the display output of the extensometer.