JP2002357521A - Material testing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a material testing machine whose costs can be reduced although provided with an equal function, as compared with the case where a safety cover with a conventional interlock mechanism is mounted as a safety mechanism for preventing an operator from putting his hand or the like into a test space during a test. SOLUTION: A photographing means 40, which photographs a part near a clamp during the test and an image processing means 33 by which the existence of a moving object inside the visual field of the photographing means 40, is discriminated by using its output are installed at the material testing machine. When the movable object is detected, drive of load mechanism is stopped automatically. Thereby, irrespective of the type or the dimensions of the testing machine, the safety mechanism can be constructed of a definite constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a material testing machine.

[0002]

2. Description of the Related Art In a material testing machine, grips are generally attached to a table and a crosshead, and the crosshead is moved while holding both ends of the test piece with the grips. It is configured to provide a load. In such a material testing machine, conventionally, as a safety measure at the time of its use, a safety cover covering a test space including a gripper is attached, and an interlock mechanism is attached to the safety cover.
Measures are known that prevent the test from starting when the safety cover is not closed. This safety cover may be installed for the purpose of preventing the specimen from scattering when it breaks, or for the purpose of preventing workers or other parts of the body from entering the test space during the test. is there.

[0003] In the conventional material testing machine, when the test piece is usually mounted on the grip, the end of the test piece is inserted between the grip teeth of the grip.
Grip by manually closing the gripping teeth. Further, in the automatic machine, while using a gripper that the gripping teeth are opened and closed by driving the actuator, in a state where the test piece is transported and positioned so that one end of the test piece is located between the gripping teeth of the gripper by the transporting means, Grip by closing the gripping teeth.

[0004]

By the way, in order to cover the test space with the safety cover, it is necessary to design and manufacture covers of various shapes and sizes depending on the size and model of the testing machine, which is costly. There is a problem.

A first object of the present invention is to provide a conventional safety cover with an interlock mechanism as a safety mechanism for preventing a worker from putting his / her hand into a test space during a test. An object of the present invention is to provide a material testing machine capable of reducing costs while having the same functions.

In a conventional material testing machine, when a test piece is gripped by a gripper, the gripper is held by one hand while the end of the test piece is positioned between the gripping teeth, and the gripper is gripped by the other hand. There is a problem that it is necessary to operate and close the gripping teeth, and the operation is not easy. Here, in the automatic machine, the mounting of the test piece to the gripper is automatically performed, but since the control of the mounting operation is a sequence control, the test piece is not properly gripped by the gripper. Also has the problem that the test is started.

Accordingly, a second object of the present invention is to provide a material testing machine capable of easily and reliably mounting a test piece to a wig.

[0008]

According to a first aspect of the present invention, there is provided a material testing machine for applying a load while a test piece is gripped by a gripper. In a material testing machine provided with control means for a load mechanism, a photographing means for photographing the vicinity of the gripper and an image processing means for taking in an output from the photographing means and performing image processing are provided. After the start, the presence or absence of a moving object other than the moving part in the field of view of the photographing means is identified, and the drive of the load mechanism is automatically performed when the presence of the moving object excluding the device member moving with the test operation is detected. It is characterized by supplying a stop command to the control means.

Here, in the invention according to claim 1,
After the image processing means recognizes that the test piece has been manually gripped by the gripping tool before the start of the test, and automatically recognizes that the hand has been pulled from the gripping tool, the control is automatically performed. It can be configured to supply a test start command to the means (claim 2).

In order to achieve the second object, a grip is provided for gripping the test piece with a pair of gripping teeth by driving an actuator, and a material for applying a load while gripping the test piece with the grip is used. In the testing machine,
A photographing means for photographing the vicinity of the gripper; and an image processing means for taking in an output from the photographing means and performing image processing. The image processing means includes a moving object in a field of view of the photographing means before the start of a test. At the same time that the test piece in the moving object is recognized as being inserted between the pair of gripping teeth of the gripper, a drive command is issued to the actuator to automatically close the gripping teeth. Is characterized by supplying

In the invention according to the third aspect, each of the grips for gripping both ends of the test piece is attached to the crosshead and the table, respectively, and any one of the grips is driven by a drive command from the image processing means. After closing a pair of gripping teeth of one gripper and gripping one end of the test piece, the crosshead automatically moves to a preset test start position, and a pair of gripping teeth of the other gripper. Can be closed so that the other end of the test piece is gripped (claim 4).

In each of the above-mentioned claims, a measurement image for measuring the elongation of the test piece in the tensile direction and / or the width change in the direction perpendicular thereto during the test using the output of the photographing means. A configuration having a processing means (claim 5) can be adopted.

According to the first aspect of the present invention, an image of the vicinity of the gripper is taken during a test, and automatic detection is performed when a moving object other than a device member that moves with the test operation is recognized in the vicinity of the grip, which is a test space. The first object is intended to be achieved by stopping the test operation.

That is, the output of the photographing means for photographing the vicinity of the gripper during the test is subjected to image processing by the image processing means, and a moving object other than the device member which moves in the field of view, that is, near the gripper with the test operation. If is found, stop the test operation. Therefore, according to the present invention, a personal computer attached to most material testing machines for test control and data processing of test results is used, and a camera and an image board as photographing means are used as hardware. And the addition of image processing software to identify moving objects, the operator's hands, etc. can be created using a common hardware / software configuration regardless of the size and model of the tester. A safety mechanism for entering the test space can be constructed, and the cost can be reduced as compared with a case where a safety cover and an interlock mechanism corresponding to the size and type of the test machine are provided.

Further, if such photographing means and image processing means for identifying a moving object are used, they can be operated before the start of the test, and the test piece can be gripped by the gripper as in the second aspect of the present invention. After recognizing the fact that the gripping tool has been pulled, it can be provided with a function of automatically starting the test at that time.

According to a third aspect of the present invention, a photographing means, which is a main configuration in the first aspect, and an image processing means for detecting a moving object by using its output have a common main configuration. In addition to the above, a configuration is provided in which the opening and closing of the gripping teeth of the gripper is performed by driving an actuator, and an image of the vicinity of the gripper is taken before the test starts, and the presence or absence of a moving object in the field of view is identified. Identify that the test piece has been inserted between the pair of gripping teeth of the gripper, hold the test piece with one hand by automatically closing the pair of gripping teeth and grasping the test piece at that point. Compared to the manual type that opens and closes the gripping teeth, the gripping operation of the test piece can be made easier. Automatic closing teeth Compared to the gripping of the specimen can be reliably reduction, it is possible to achieve the second object.

In the invention according to the third aspect, the function of closing the gripping teeth when the test piece is inserted between the pair of gripping teeth is provided in each gripping tool for gripping both ends of the test piece. And in that case,
As in the invention according to claim 4, when the gripping teeth of one of the grippers are automatically closed as described above and one end of the test piece is gripped, the crosshead is automatically moved, and the other gripper is moved. By automatically recognizing that the other end of the test piece has been inserted between the gripping teeth and closing the gripping tooth, it is possible to easily and reliably grip both ends of the test piece.

In the invention according to each of the above-mentioned claims, there are provided photographing means for photographing the vicinity of the gripper, and image processing means for identifying the presence or absence of a moving object by using the output of the photographing means. A known video type extensometer and a video signal for measuring the elongation and width change of the test piece from the photographing signal of the test piece under test by the photographing means, that is, the camera and the image board, according to the invention according to claim 5. A material testing machine having a video extensometer and / or a width change measuring function using a video signal can be used also as a photographing means in a width change measuring function using a method.
When applying the inventions of (1) to (4), only the image processing means (software) required in each of these claims is substantially added, and the invention of each of the above claims is realized at low cost. can do.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of an embodiment of the present invention, and is a diagram showing both a schematic diagram showing a mechanical configuration and a block diagram showing an electrical configuration.

The tester main body 1 has a structure in which two screw rods 12a and 12b are vertically arranged on a table 11, and both ends of a crosshead 13 are supported on the screw rods 12a and 12b via nuts. have. Each screw rod 1
2a, 12b are given rotation by the driving device 14,
The cross head 13 moves up and down by the driving of the driving device 14.

The test piece W is gripped at both ends by grippers 15a and 15b mounted on the table 11 and the crosshead 13, respectively.
By raising 3, a tensile load is applied to the test piece W. Each of the grippers 15a and 15b grips the test piece W by opening and closing a pair of gripping teeth T, respectively.
The gripping teeth T are opened and closed by driving the chuck mechanisms 16a and 16b each having a hydraulically driven or electric actuator.

The displacement of the crosshead 13 is determined by a displacement sensor 17.
The load acting on the test piece W is detected by the load cell 18 and the load is detected by the amplifier 21.
After being digitized by A / D converters 22a and 22b via a and 21b, they are taken into a control device 30 described later.

Now, the cover of one of the screw rods 12a is CC
The D camera 40 is fixed, and the CCD camera 40
Has a field of view set so as to photograph a test space including the grippers 15a and 15b and the test piece W gripped by the grippers 15a and 15b. The output of the CCD camera 40 is taken into the control device 30 via the image board (capture board) 41 at predetermined minute intervals.

The control device 30 is actually constituted by a computer and its peripheral devices, and executes various functions in accordance with installed programs.
For the sake of simplicity, FIG. 1 shows a set of blocks for each function.

The displacement data and load data detected by the displacement sensor 17 and the load cell 18 are as follows:
Each is taken into the data processing unit 31 of the control device 30. In addition, photographing data obtained by the CCD camera 40 via the image board 41 is used for image processing of both the measurement image processing unit 32 and the moving object identification image processing unit 33.

The image processing unit for measurement 32 obtains the instantaneous elongation and the change of the width (dimension in the direction perpendicular to the load axis) of the test piece W by image processing of the test piece W during the test, and obtains the result. The data is supplied to the data processing unit 31. In the data processing unit 31,
The displacement data by the displacement sensor 17, the load data by the load cell 18, and the measurement results of the elongation and the width change of the test piece W by the measurement image processing unit 32 are associated with, for example, a load-elongation curve or the like, and are stored in the data storage unit 34. It is stored and displayed on the display 50.

The drive mechanism 14 for driving the cross head 13 is controlled by a drive control signal supplied from a drive control unit 35. During the test, of the displacement, load, and elongation, the physical quantity set as the control amount is fed back to the preset target value, so that the test piece W is cross-linked so that the load according to the target value is applied. The head 13 is driven. In addition, each grip 15a,
Chuck mechanism 16a, 1 for opening and closing gripping tooth T of 15b
6b is operated by a drive signal supplied from the chuck controllers 36a and 36b.

An operation unit 60 is connected to the control device 30. By operating the operation unit 60, the crosshead 13 is manually moved up and down.
The gripping teeth T of 5a and 15b can be opened and closed.

During the test and before the start of the test, the moving object identification image processing section 33 performs the following operations, respectively, by the drive control section 35 and the chuck control sections 36a and 36a.
A drive command is supplied to b.

That is, the moving object identification image processing section 33
Identifies whether there is a moving object in the field of view of the CCD camera 40 during the test. The identification of the moving object takes a difference from the previous information every time frame information is taken in at every predetermined minute time. By this difference processing,
The stationary part in the field of view is erased, an image of only the moving object remains, and the presence or absence of the moving object can be detected from the information after the difference. When a moving object is detected, an operation stop command is given to the drive control unit 35 to stop the crosshead 13.

Therefore, even if an operator accidentally brings his / her hand or the like into the field of view of the CCD camera 40, that is, the test space during the test, the crosshead 13 is automatically stopped. Therefore, safety can be ensured without providing a device.

The moving object detecting image processing unit 33
Before the start of the test, the moving object is detected by performing the difference processing of the frame information after a predetermined minute time in the same manner as described above, and the test piece W in the moving object is identified. One of the grips 1
Recognizing that it has been inserted between the gripping teeth T of 5a, 15b, it gives a command to close the chucking tooth T to the chuck controller 36a or 36b corresponding to the corresponding gripping tool 15a or 15b. Next, after a command is supplied to the drive control unit 35 to move the crosshead 13 to the test start position, the gripping teeth T of the other gripping tool 15a or 15b are
It recognizes that the other end of the test piece W has been inserted in the same manner as above, and gives a command to close the chuck tooth T to the corresponding chuck control unit 36a or 36b.

Therefore, when mounting the test piece W, the operator holds the test piece W and inserts one end of the test piece W between the gripping teeth T of one of the gripping tools, for example, the upper gripping tool 15b. After the tool 15b is closed and the crosshead 13 is moved to the prescribed position, the other end of the test piece W is simply inserted between the gripping teeth T of the lower gripping tool 15a. Are semi-automatically gripped, so that the work of mounting the test piece W can be performed easily and reliably.

Further, the moving object detecting image processing section 33 includes:
As described above, the grips 15a, 15
Even after grasping with the b, the presence or absence of a moving object is identified within the field of view of the CCD camera 40, and it is recognized that the hand has been pulled from the vicinity of the grippers 15a, 15b, and the drive is automatically performed at the time of the recognition. A test start command is supplied to the control unit 35 to automatically shift the crosshead 13 to a test operation.

The CCD according to the above embodiment of the present invention
The operation of the moving object identification image processing unit 33 using the photographing data of the camera 40 is summarized as follows.
b between the gripping teeth T, the gripping tool 15a or 15b automatically closes and grips one end of the test piece W, and then the crosshead 13 automatically moves to the test start position, In this state, by inserting the other end of the test piece W between the gripping teeth T of the other gripping tool 15a or 15b, the gripping tool 15a or 15b is closed and the mounting of the test piece W is completed. Tool 15
The test starts automatically by subtracting from a and 15b. And, during the test, the grippers 15a, 15
When a hand or the like is brought close to b, the crosshead 13 is automatically stopped for safety and the test operation is stopped.

It should be particularly noted in the above embodiment that the image information to be processed by the moving object identification image processing section 33 is a CCD for measuring the elongation or width change of the test piece W. This is the point that the image information from the camera 40 is used. Therefore, in a material testing machine having such a video type extensometer, each function by the moving object identification image processing unit 33 described above is used. There is substantially no hardware to be added in order to provide the functions described above, and it is only necessary to add image processing software for identifying a moving object, and the above functions can be provided at low cost.

In the above embodiment, an example has been described in which the image information to be processed in the moving object identification image processing unit 33 is the image information from one CCD camera 40, but it should be monitored. If the area is large, multiple CCs
It is needless to say that a D camera may be arranged, and image information from one or a plurality of line sensors may be used.

[0038]

As described above, according to the first aspect of the present invention, the presence or absence of a moving object is identified by performing image processing on the output from the photographing means for photographing the vicinity of the gripper during the test.
The test operation is automatically stopped when a moving object is detected, so the safety cover and interlock mechanism according to the model and size of the testing machine are equivalent to the conventional countermeasures at a lower cost. Functions can be provided.

According to the second aspect of the present invention, when the test piece is mounted by the gripper using the identification function of the presence or absence of the moving object, and when it is detected that the hand is pulled from the gripper, The test workability can be improved by configuring to automatically start the test.

On the other hand, according to the third aspect of the present invention, before the start of the test, the output from the photographing means for photographing the vicinity of the grip is image-processed to identify the presence or absence of the moving object, and the test in the moving object is performed. Recognizes that a piece has been inserted between the gripping teeth of the gripper, and automatically closes the gripping tooth at that point, making the operation for gripping the test specimen much easier than in the past. In addition, the gripping of the test piece can be made more reliable than the gripping operation of the test piece by an automatic machine that transports and grips the test piece based on the sequence control.

Further, as in the invention according to claim 4, by inserting one end of the test piece between the gripping teeth of one gripping tool, the gripping tool is automatically closed and the test piece is gripped in the same manner as described above. After that, the crosshead is automatically moved to the test start position, and the other end of the test piece is inserted between the gripping teeth of the other gripper, thereby automatically closing the gripper and gripping the test piece. With such a configuration, the work of mounting the test piece can be further facilitated.

As in the fifth aspect of the present invention, the photographing means for measuring the elongation and / or width change of the test piece is shared with the photographing means in the above-mentioned inventions. The cost for providing each function can be relatively reduced, and a material testing machine having various functions at low cost can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention, showing a schematic diagram representing a mechanical configuration and a block diagram representing an electrical configuration.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tester main body 11 Table 12a, 12b Screw rod 13 Cross head 14 Load mechanism 15a, 15b Gripping tool 16a, 16b Chuck mechanism 17 Displacement sensor 18 Load cell 30 Control device 31 Data processing unit 32 Measurement image processing unit 33 Moving object identification Image processing unit 34 Storage unit 35 Drive control unit 36a, 36b Chuck control unit 40 CCD camera 41 Image board 50 Display unit 60 Operation unit T Grab W W Test piece

Claims (5)

[Claims] 1. A material testing machine provided with a load mechanism for applying a load while a test piece is gripped by a gripper, and a photographing means for photographing the vicinity of the gripper, and a photographing means therefor. Image processing means for taking in the output from the apparatus and performing image processing, the image processing means identifying the presence or absence of a moving object within the field of view of the photographing means after the start of the test, and moving the apparatus member along with the test operation A material testing machine for automatically supplying a drive stop command of the load mechanism to the control means when the presence of a moving object other than the above is detected. 2. After the image processing means recognizes that the test piece has been manually gripped by the gripping tool before starting the test, and then recognizes that the hand has been pulled from the gripping tool, The material testing machine according to claim 1, wherein a test start command is automatically supplied to the control means. 3. A material testing machine, comprising: a grip for gripping a test piece with a pair of grip teeth by driving an actuator, and applying a load while gripping the test piece with the grip, wherein an image of the vicinity of the grip is taken. Image capturing means, comprising an image processing means for taking an output from the image capturing means and performing image processing, and this image processing means identifies the presence or absence of a moving object in the field of view of the image capturing means before the start of the test, When recognizing that the test piece in the moving object has been inserted between the pair of gripping teeth of the gripper, supplying a drive command to the actuator to automatically close the gripping teeth. Material testing machine. 4. A grip for gripping both ends of a test piece,
After having closed the pair of gripping teeth of one of the gripping tools and holding one end of the test piece by a drive command from the image processing means, the crosshead is 4. The apparatus according to claim 3, wherein the test piece automatically moves to a preset test start position, closes the pair of gripping teeth of the other gripping tool, and grips the other end of the test piece. Material testing machine according to 1. 5. Using the output from the photographing means according to claim 1, 2, 3 or 4, measure the elongation of the test piece in the tensile direction and / or the width change in the direction perpendicular to the direction during the test. A material testing machine, comprising: a measurement image processing means for performing measurement.