JPH0643724Y2 - Material testing machine - Google Patents

Description

[Detailed Description of the Invention] A. Industrial Application Field of the Invention The present invention relates to the fracture position of a test piece, in particular, the A fracture which is a specific area in the central portion between the gauge marks of the test piece or the B fracture which is an upper and lower area thereof. The present invention relates to a material testing machine capable of automatically detecting

B. Conventional technology There are three types of fractures that occur during tensile testing of test pieces: A fracture, B fracture and C fracture. As shown in FIG. 2, the A fracture is a fracture occurring in the central two regions 1A when the gauge marks P ₁ and P ₂ of the test piece 1 are equally divided into four, and the B fracture is the central 2
The fracture occurs in the area 1B adjacent to the upper and lower ends of the area 1A, and the fracture C occurs in the area 1C adjacent to the outside of the reference points P ₁ and P ₂ .

Conventionally, a visual determination method and an energization determination method are known as methods for determining such breakage. In the energization determination method, the test piece is energized via the upper and lower grips and the lever of the displacement gauge attached to the gauge of the test piece, and the current is cut off in any path between the upper and lower grips and the upper and lower gauge. Whether it is A break, B break or C break is discriminated depending on whether it is high or low.

C. Problem to be Solved by the Invention However, the visual discrimination method has a problem that the fracture position is apt to be erroneous and cannot be accurately discriminated, and the energization discrimination method cannot discriminate between A fracture and B fracture. .

Therefore, the laser beam is scanned in the width direction of the test piece, and the scan lines are arranged in the load axis direction at a predetermined pitch within the A and B fracture areas to recognize the bright / dark pattern obtained for each scan line. A method of automatically discriminating can be considered. However, in order to identify in which region the fracture has occurred, it is necessary to make the scanning lines at predetermined pitches throughout the fracture regions A to C, which takes a long scanning time.
There is a problem that the pattern recognition process becomes complicated and expensive.

A technical problem of the present invention is to easily and inexpensively perform automatic determination of a fracture position of a test piece.

D. Means for Solving the Problems The present invention relates to a first detecting means for detecting the presence or absence of breakage of a test piece, and a central portion between the gauges of the test piece in the load axis direction by the screw feeding mechanism. Scanning means for scanning the test piece by moving it only in a specific area, and a breakage of the test piece by detecting that the energizing current is interrupted by passing a current through at least the gauge through a displacement gauge attached to the test piece. A second detecting means for detecting and a determining means for determining whether or not the breaking point of the test piece is in the central portion specific region based on the output signals from both detecting means.

E. Function The second fracture detecting means detects the fracture between the gauge marks of the test piece, and the first fracture detecting means detects the presence or absence of the fracture in the central specific region between the gauge marks. Therefore, it is possible to discriminate between the breakage in the central specific region and the breaks in the inter-markpoint regions above and below the detection result of both detecting means. Since the first detection means moves by the screw feed mechanism, smooth and highly accurate scanning along the load axis becomes possible.

F. Embodiment FIG. 1 is an overall configuration diagram showing an embodiment of the present invention. In the figure, both upper and lower ends of the test piece 1 are connected to load rods of a tester main body (not shown) by grippers not shown. Reference numeral 10 denotes an elevating table which is supported by a tester body (not shown) and moves up and down horizontally along the longitudinal direction of the test piece 1. One side edge of the elevating table 10 is cut so as to surround the test piece 1 on three sides. The notch 10a is formed. The notch 10a has a size that allows the robot hand for automatically mounting the test piece to escape. Lifting table like this
An optical detection device 11 for optically detecting the presence or absence of A fracture of the test piece 1 is installed on the test piece 10.

The optical detection device 11 includes a light emitter 12 and a light receiver 13, which are arranged in the vicinity of the notch 10a on the elevating table 10 so as to face each other via the test piece 1 in the notch 10a, and the light emitter 12 and the light receiver 13. The light guide optical fibers 12a and 13a are provided so as to extend in the direction of the test piece 1 with their optical axes aligned with the tips. The output signal of the light receiver 13 has a high level when there is a break, and has a low level when there is no break, and this level signal is input to the control unit 14. Reference numeral 15 is a drive motor for moving the lifting table 10 up and down, and the driving motor 15 is connected to a feed screw 16 screwed to the lifting table 10.

The control unit 14 determines the breaking position of the test piece 1 and the drive motor.
A central processing unit (hereinafter referred to as a CPU) 141 that manages and controls the whole, which controls lifting and lowering in an A fracture area of A, a ROM 142 that stores a program for determining a fracture position and a motor control, and a CPU 141. It is equipped with a RAM 143 that stores the calculation results of the above and various input data, an input interface 144 and an output interface 145.
It is connected to the CPU 141 via 46.

Reference numeral 17 denotes a breakage detection circuit that detects the presence or absence of breakage of the test piece 1 by energization. The detection circuit 17 includes a first breakage detector 171 which is operated by cutting off the power even if any breakage area (A, B, C break areas) of the test piece 1 shown in FIG. 2 is broken,
Breaking region below the upper gauge P ₁ of the test piece 1 (1A, 1B, 1C)
There a second fracture detector 172 operates is de-energized when broken, fractured area below the lower gauge P ₂ of the test piece 1 (1
And (3) a third breakage detection unit 173 which is operated when the current is cut off when the breakage occurs. One end of each of the breakage detectors 171-173 is connected to the power supply voltage + V (5V). The other end of the first breakage detector 171 is connected to the upper end of the test piece 1, and the other ends of the second and third breakage detectors 172 and 173 are mechanically connected to the gauge marks P ₁ and P ₂ of the test piece 1. It is connected to the arms 18a and 18b of the lever-type displacement gauge 18 that is mounted as a whole. The lower end of the test piece 1 is grounded so that the breakage detecting units 171 to 173 can be energized.

Signals when the breakage detectors 171 to 173 are energized and cut off according to the presence or absence of breakage of the test piece 1 are input to the control unit 14 through the input interface 144. Optical detector 11 optical receiver
The output signal from 13 is also captured by the control unit 14 through the input interface 144. The output interface 145 of the control unit 14 is connected to the drive motor 1 via the motor drive circuit 19.
5 is connected.

Next, the operation will be described.

Before applying a load, the power supply voltage V is connected to the test piece 1 through the breakage detectors 171-173, and a current for breakage detection is applied to the test piece 1. When a tensile load is applied to the test piece 1, the test piece 1
When the break occurs, the CPU 141 detects the break of the test piece 1 and stops the load mechanism (not shown) based on the signals from the break detectors 171-173.

Here, if the breakage as shown in FIG. 1 occurs in the A breakage region 1A of the test piece, the first breakage detector 171 and the second breakage detector 172 are de-energized. The outputs of the second breakage detectors 171 and 172 are "0", and the outputs thereof are "1" because the third breakage detector 173 is energized. Therefore, each breakage detector 171-173 as described above is
The control unit 14 that has received the respective outputs from outputs the reset command from the CPU 141 to the motor drive circuit 19 through the output interface 145 by determining that the output of the first breakage detector 171 is “0”. As a result, the drive motor 15 is started and the feed screw 16 is rotated to raise or lower the elevating table 10.
The optical axis of the light receiver 13 is made to coincide with the upper end or the lower end of the A break region 1A of the projector 12 constituting the above and is stopped. This initial position setting operation may be performed before applying a load.

Thereafter, the CPU 141 outputs a scan operation command to the motor drive circuit 19 to start the drive motor 15 and rotate the feed screw 16 to lower or raise the lifting table 10. As a result, the light beam emitted from the projector 12 of the optical detection device 11 scans the A fracture area 1A from the upper end to the lower end or vice versa. As shown in FIG. 1, if the breakage occurs in the breakage area 1A of A, the light beam transmitted through the gap at the breakage portion is received by the optical receiver 13
Is received, and a high level signal is transmitted from the light receiver 13. This output signal is C through the input interface 144.
When taken in by the PU 141, the CPU 141 executes a predetermined process to determine whether or not there is a break in the A break area 1A. That is, in the case shown in FIG. 1, it is determined that a fracture has occurred in the A fracture area 1A.

Since the amount of movement of the drive motor 15 from the initial position is commanded in advance, when the position of the optical axis of the light emitter 12 and the light receiver 13 reaches the lower end or the upper end of the A fracture area 1A, the drive motor 15
Will stop automatically. Since the optical fibers 12a and 13a for guiding light are respectively projected from the light emitter 12 and the light receiver 13,
When a light source or a light receiving element cannot be installed near the periphery of the test piece 1, a light source or the like can be installed in a place where space is available, and light can be guided to the vicinity of the test piece by an optical fiber. Further, even if the distance between the light projector 12 and the light receiver 13 is widened, the optical fiber prevents the light from being diffused, so that the breakage can be reliably detected.

The truth table shown in Table I below shows the output results of the breakage detectors 171 to 173 and the optical detection device 11 at the time of breakage of A, B, and C, and the breakage determination result in the control unit 14. “0” of the breakage detectors 171 to 173 indicates that the output state in which the power supply is cut off is “0” of the optical detection device 11.
Indicates an output state without transmitted light, "1" of the breakage detectors 171 to 173 indicates an energized output state, "1" of the optical detection device 11 indicates an output state with transmitted light, and "x" Indicates that "0" or "1" is irrelevant to the determination processing of the CPU 141.

As is apparent from Table I, when the output of the first breakage detector 171 is "0" and the other outputs are "x", the control unit 14 stops the load mechanism and sends a reset command to the drive motor 15. Further, when the output of the first breakage detector 171 is "0", the output of the optical detection device 11 is "1", and the others are "x", it is determined that the breakage is A. When all the outputs are "0", the outputs of the first breakage detector 171 and the optical detection device 11 are "0", and the outputs of the second and third breakage detectors 172 and 173 are "1", the C break is occurred. Determine that.

In the present embodiment as described above, the first operation is performed by the high and low output signals of the optical detection device 11 that scans the A fracture area 1A and the presence or absence of energization according to the fracture position of the test piece 1.
~ Since the break position is determined by the output signals from the third break detectors 171-173, each break of A, B, C can be easily and surely judged, and the judgment process is also low. Can be done at cost. Further, since it is a screw feed type, smooth and highly accurate scanning can be performed at low cost.

In the configuration of the above embodiment, the optical detection device 11 is the first detection means, the breakage detection circuit 17 is the second detection means, the drive motor 15 and the feed screw 16 are the scanning means, and the control unit 14 is the determination means. Respectively.

In the above embodiment, the case of discriminating A, B, and C fractures has been described, but the first fracture detector 171 may be omitted when discriminating between A fracture and B fracture.

Further, as the means for detecting the presence or absence of A breakage based on the signal level by the high level and low level signals, not only the transmissive type as shown in the above embodiment, but also the reflective type, proximity switch type, ultrasonic wave, etc. are used. You can It should be noted that the present invention is not limited to the identification of the A to C fracture areas by the partitioning method as shown in FIG. 2, but identifies the central specific area between the gage marks and the areas above and below the particular area between the gage marks. It can be applied to things.

G. Effect of the Invention Since the invention is constructed as described above, for example, A break and B break
It is possible to automatically distinguish between the breakage in the central specific area or the breaks in the areas above and below it, which is called a break. Also, the first
Since the detecting means is moved only in the central specific region, the moving distance becomes shorter and the fracture position detection time can be shortened as compared with the method of moving the entire fracture region between the reference points. Furthermore, since the screw feed type scanning means is adopted, smoother and more accurate scanning can be performed as compared with the cylinder feed type or the wire and pulley type feeding system. Furthermore,
If the method of detecting the presence or absence of breakage in the central specific region as the magnitude of the signal level is used, the cost can be reduced as compared with the laser beam method, and a complicated breakage determination algorithm is not required, and the device can be configured simply.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention, and FIG. 2 is an explanatory diagram of a test piece. 1: Test piece, 1A: A fracture area 10: Lifting table, 11: Optical detection device 14: Controller, 15: Drive motor 16: Feed screw 17: Breakage detection circuit

Claims (1)

[Scope of utility model registration request] 1. A first detection means for detecting the presence or absence of breakage of a test piece, and the detection means is moved by a screw feed mechanism in the load axis direction and only in a central region specified between the gauge marks of the test piece. Second detecting means for detecting breakage of the test piece by detecting a breakage of the energized current by passing a current between at least the reference points through a displacement means mounted on the test piece and a displacement gauge attached to the test piece. And a discriminating means for discriminating whether or not the break point of the test piece is in the central portion specific region based on the output signals from the both detecting means.