JPS63158436A - Tension tester - Google Patents

Abstract

PURPOSE:To emphasize contrast between ground color and bench marks and conduct a sure measurement by constituting the position of a light source so as to be freely movable and enabling an irradiation angle relative to a test piece to be arbitrarily changed. CONSTITUTION:When a television camera 1 sensors a test piece S, resultant output signals are outputted with portions P0 and P0 corresponding to two bench marks Q and Q, respectively, to be higher level signals as compared with the other portions when the directions of scanning lines HS are parallel or perpendicular to a tensile direction. Accordingly, when only output signals higher than a prescribed level E1 are taken out of those output signals by a processing circuit 3, output signals with a time interval T corresponding to a spacing 1 corresponding to the bench marks Q and Q can be obtained and a distance L between the bench marks can be obtained from last-said output signals.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an improvement in a tensile testing device that utilizes a surface scanning device that outputs electrical signals corresponding to optical characteristics, such as a television camera. be.

[Prior art]

Conventionally, in a tensile testing device that measures the tensile strength, elastic modulus, etc. of materials such as rubber, a pair of marked lines are attached to the surface of a sample piece cut out from the material at two locations separated in the tensile direction, and two marks are placed at both ends of the sample piece. It was common for a measurer to visually measure the distance between the marked lines, which changes by pulling the line, using a scale or the like. However, such a visual measurement method has the drawbacks that the measured values vary depending on the measurer and lacks reproducibility, and the measurement work is also very complicated.

In order to solve such problems, the present applicant previously proposed in Japanese Patent Publication No. 56-19882 (Patent No. 1080186) to automatically measure the distance between gauge lines using a surface scanning device such as a television camera. We have proposed a tensile testing device that does this.

This commercialized device uses a black-and-white television camera as a surface scanning device, which is very convenient for measuring the distance between the white marked lines on a black rubber specimen, and improves measurement efficiency. It was something to do.

However, as materials have become more colorful in recent years, and rubber has come in a variety of colors, depending on the color of the material, the marking lines on the sample piece may become difficult to distinguish using a black-and-white television camera. , some things became impossible to measure.

A solution to this problem is to use a color television camera as the surface scanning device, but this color television camera has the disadvantage that it is much more expensive than a black and white television camera. We also tried a method of coloring the surface of the sample piece with black ink as a simple method, but as the sample was pulled, the surface coloring of the black ink faded and the ground color of the material came out, so in the end, the essence It wasn't a viable solution.

[Purpose of the invention]

An object of the present invention is to provide a tensile testing device that uses a surface scanning device, and to be able to reliably measure the distance between gauge lines regardless of the color of the sample piece, even if a black and white television camera is used as the surface scanning device. The objective is to provide a tensile testing device that can

[Structure of the Invention] The present invention achieves the above object by attaching marked lines to at least two places on the surface of a sample piece, gripping both ends of the sample piece, and applying light from a light source in the direction in which the marked lines are separated. In the tensile testing apparatus, the distance between the marked lines is measured by a surface scanning device that outputs an electric signal corresponding to the optical property of the specimen. It is characterized by being changeable.

Hereinafter, the present invention will be explained with reference to embodiments shown in the drawings.

Fig. 1 schematically shows the tensile test apparatus according to the present invention when viewed from above, where S is a sample piece cut out from a material such as rubber, and 1 is a sample piece oriented in a direction perpendicular to the surface of this sample piece S. This television camera corresponds to a surface scanning device that outputs electrical signals corresponding to optical characteristics in the present invention.

Reference numeral 2 denotes a light source that generates high-frequency light, such as a fluorescent lamp, and is provided so that its center position can be moved in the direction of arrow B, so that the irradiation angle θ with respect to the surface of the sample piece S can be arbitrarily changed. ing.

The sample piece S has a shape as shown in FIGS. 2A and 3A when viewed from the front (viewed from the arrow A in FIG. 1), with marked lines Q and Q is attached at a predetermined distance. As the color of this mark f%lQ, a mortar or black is appropriately selected depending on the color of the sample piece S.

When measuring tensile properties such as tensile strength and elastic modulus, the sample piece S marked with the marked line Q is held at its upper and lower wide ends by clamp fittings (not shown), and the sample piece S marked with the marked line Q is held at two marked lines. A tensile load is applied in the direction in which Q and Q are separated. Then, the change in the distance between these two gauge lines Q and Q is imaged by the television camera 1, which is a surface scanning device.

When the television camera 1 images the sample piece S, the output signal will be as shown in FIG. 2B when the direction of the scanning line H8 is parallel to the tensile direction as shown in FIG. 2A, and as shown in FIG. When the direction is perpendicular to the tensile direction as in Figure 3A, Figure 3B
The Po+Po portions corresponding to the two marked lines Q and Q are output as signals with a higher level than the other portions. Therefore, if the processing circuit 3 extracts only those output signals that are higher than a certain level E among such output signals, an output signal with a time interval T corresponding to the interval corresponding to the marked lines Q and Q can be obtained. The distance between the gauge lines can be calculated from the output signal.

As mentioned above, according to the conventional tensile test equipment, if a black and white television camera is used as a surface scanning device, if the sample piece is colored rubber such as red, yellow, pink, green, etc., it will be marked with black or white. There was a problem that the contrast with the marked line was insufficient, making identification difficult and making measurement impossible. As a result of various studies on this point, the inventors of the present invention found that the illumination angle θ of the light source 2 with respect to the sample piece S By changing the color of the specimen S according to the color of the specimen S, it becomes possible to emphasize the contrast with the marked line Q marked in white or black, which makes it possible to identify even a black and white television camera. I found out that it becomes possible to do this. That is, in the tensile test apparatus of the present invention, the setting position of the light source 2 is configured to be movable as described above, and the irradiation angle θ with respect to the sample piece S is arbitrarily changed by moving the light source 2. This allows the tensile properties to be measured even for colored samples.

The table below shows sample pieces (colored rubber) with various different colors, and the maximum contrast is determined by varying the irradiation angle of the light source and determining the brightness Y of the color of each sample piece using a color difference photometer according to JIS regulations. The irradiation angle θ at which is large,
That is, the irradiation angle θ was determined so that the marked line can be identified even with a black-and-white television camera.

However, the value of θ in the table below is not absolute as it is also affected by the brightness around the test machine, and the illumination angle may vary slightly from what is shown in the table depending on the surrounding brightness. .

(Margin below this page) In the above table, white marked lines are attached to Nos. 001 to 7, and black marked lines are given to Nos. 088 to 13.

In this way, when the brightness Y is less than 40 (Y<40), it is recommended to use white as the color of the marking line, and when the brightness Y is larger than 40 (Y≧40), it is recommended to use black. When using the 4° line, it is preferable to map it onto the television screen using a black and white inversion mechanism.

In addition, the preferred range of irradiation angle θ that can emphasize the contrast with the marked line according to the color of the sample piece is as follows:
The following procedure may be performed depending on the lightness Y of the color of the sample piece.

When Y≦10 30≦θ 10 When Y≦15 20≦θ≦3015<Y<7
When 0, 8≦θ≦20 [Effects of the Invention] As described above, in the tensile test device using the surface scanning device according to the present invention, the position of the light source is configured to be movable, and the irradiation angle to the sample piece can be arbitrarily set. Since it can be changed, even if a black-and-white television camera is used as a surface scanning device, the contrast between the ground color and the gauge line can be emphasized by appropriately selecting the irradiation angle, regardless of the color of the sample piece. This allows for reliable measurements.

[Brief explanation of the drawing]

FIG. 1 is a plan view schematically showing the tensile test apparatus of the present invention;
Figure 2A is an explanatory diagram of the situation when the scanning line is set in the tensile direction of the sample piece by the surface scanning device of the same device, as seen in the direction of arrow A in Figure 1, and Figure 2B is an illustration of the situation when the same scanning An explanatory diagram showing the output signal obtained, Fig. 3A shows the situation when the scanning line is set perpendicular to the tensile direction of the sample piece by the surface scanning device of the same device, in the direction of arrow A in Fig. 1. Explanatory diagram as seen, Figure 3B
is an explanatory diagram showing an output signal obtained by the same scanning. l...TV camera (surface scanning device), 2...light source, 3...processing circuit, S...sample piece.

Claims (1)

[Claims] Marked lines are attached to at least two places on the surface of a sample piece, and the sample piece is gripped at both ends and irradiated with light from a light source while being pulled in a direction in which the marked lines are separated to output an electrical signal corresponding to the optical characteristics. A tensile testing device configured to measure the separation distance between the gauge lines using a surface scanning device, characterized in that the light source is configured to be movable and the irradiation angle to the sample piece can be changed.