JP3422138B2 - Material testing machine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a material testing machine having a display device for displaying a load applied to a test piece by an analog pointer.

[0002]

2. Description of the Related Art As a display device of a material testing machine for displaying a load applied to a specimen by an analog pointer, an actual fair 6
The one disclosed in Japanese Patent Publication No. 45222 is known.
In this device, the output of the pulse motor is transmitted to the rotating shaft of the pointer through the timing belt to control the angle of the pointer. A pulse (electrical signal) according to the load is input to the pulse motor, and the pulse motor rotates by an angle according to the load. The rotation of the motor is transmitted by the timing belt to rotate the pointer, and the position of the pointer is read by the scale of the pointing plate. Since the pulse motor has good rotation control accuracy and a large static torque, it is possible to drive the pointer accurately.

[0003]

However, the conventional material testing machine is not provided with a mechanism for automatically returning the pointer to the zero position after the end of the test. Therefore, at the time of the next test, it is necessary to operate the operation panel to return the pointer to the zero position, and after this work, the next test piece can be finally tested. In this way, complicated operations are inevitable in preparation for the next test.

An object of the present invention is to provide a material testing machine having a display device capable of automatically initializing the position of a pointer.

[0005]

According to a first aspect of the present invention, in a material testing machine equipped with a display device for displaying a load acting on a specimen by an analog pointer, the display device rotationally drives the analog pointer. Pulse motor, angle detection means for detecting that the analog pointer has reached a predetermined absolute angle and outputting a signal, and continuous pulse is applied to the pulse motor to rotate the analog pointer, and continuous when the signal is received Second control means for stopping the pulse, inputting a predetermined number of pulses corresponding to the relative angle between the angle of the analog pointer and the initial angle of the analog pointer to the pulse motor, and rotating the analog pointer to the initial angle And is provided. The invention according to claim 2 is
In a material testing machine equipped with a display device that displays the load applied to the specimen using analog pointers, the display device is
A pulse motor that rotationally drives the analog pointer, an angle detection unit that detects the absolute angle of the analog pointer, and a predetermined number of pulses that correspond to the deviation between the absolute angle detected by the angle detection unit and the initial angle of the analog pointer. And a control means for inputting to the motor and rotating the analog pointer to an initial angle.

According to the first aspect of the invention, the control means applies a continuous pulse to the pulse motor to rotate the analog pointer, and when the analog pointer reaches a predetermined absolute angle, a signal output from the angle detection means is output. Stops continuous pulse when received. Further, a predetermined number of pulses corresponding to the relative angle between the angle of the analog pointer and the initial angle of the analog pointer are input to the pulse motor to rotate the analog pointer to the initial angle. In the invention according to claim 2, the control means inputs a predetermined number of pulses corresponding to the deviation between the absolute angle of the analog pointer detected by the angle detecting means and the initial angle of the analog pointer to the pulse motor, and the analog pointer is moved. Rotate to the initial angle.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a material testing machine according to the present invention will be described with reference to FIGS. As shown in FIG. 1, the test condition is input by the test condition input switch group 1, and this information is taken into the control device 2. The control device 2 outputs a signal to the electro-hydraulic servo valve 3 according to the input test conditions, and controls the load cylinder 4 that applies a load to the sample (not shown) via the electro-hydraulic servo valve 3. The pressure of the load cylinder 4 is converted into an electric signal by the pressure cell 5 and input to the control device 2. The control device 2 is a pressure cell 5
In response to the electric signal from the motor driver 6, a signal is output to the motor driver 6, and the output pulse of the motor driver 6 rotates the pulse motor 7. The load analog pointer 8 rotates in synchronization with the rotation of the pulse motor 7. With the above configuration, the analog pointer 8 is controlled to an angle according to the load.

FIG. 2 shows an indicator 9 to which an analog pointer 8 is attached. As shown in FIG. 2 (a), a large and small scale 10 is printed on the surface of the indicator 9 by equally dividing one 360 ° around the zero scale 10 A, and an analog pointer that rotates around the rotary shaft 8 A is used. By reading the scale 10 pointed at by 8, the measured value is visually recognized. On the back surface of the indicator 9, a pulley 11 fixed to the analog pointer 8 via a rotary shaft 8A is provided, and the pulley 11 is connected to a rotary shaft 7A of the pulse motor 7 via a timing belt 12. When a pulse signal is applied to the pulse motor 7,
The rotary shaft 7A rotates at a constant angle for each pulse, and the load analog pointer 8 rotates at a predetermined angle in conjunction with this rotation.

As shown in FIG. 2B, a position detecting needle 14 is provided on the back side of the indicator 9 so as to project from the rotary shaft 8A in the same direction as the analog pointer 8. Position detection needle 1
The numeral 4 always faces the analog pointer 8 and rotates together with the analog pointer 8. In addition, zero scale 1 is on the back of the indicator 9.
The proximity switch 15 is attached so as to face 0A.
The position detecting needle 14 rotates as the analog pointer 8 rotates, and when the analog pointer 8 rotates to an angle indicating the vicinity of the zero scale, the proximity switch 15 detects the approach of the position detecting needle 14 and turns on. As shown, the detection signal is the control device 2
Entered in.

FIG. 2 shows the state of the indicator 9 at the end of the test. As described above, the analog pointer 8 during the test is controlled so as to rotate in response to the rotation of the pulse motor 7 and indicate a desired scale. However, since there are no pulses for rotating the pulse motor 7 at the end of the test, the analog pointer stops at the angle designated at the end of the test. Therefore, when shifting from this state to the next test of the specimen,
The angle corresponding to the rotation of the pulse motor 7 is added from the last stopped state, and the analog pointer 8 does not indicate the correct load value. Therefore, after the end of the test or before the next test, it is necessary to initialize the analog pointer 8 toward the zero scale in preparation for the next test.

FIG. 5 is a flow chart showing a sequence for initializing the angle of the analog pointer 8 in the material testing machine of the present embodiment. This sequence is activated upon detection of test end or test start. It may be activated in association with the operation of a calibration button (not shown). The procedure will be described assuming that the analog pointer 8 is at the angle shown in FIG. The sequence starts at step S1 and proceeds to step S2. In step S2, the pulse motor 7 is rotated in a predetermined direction and the analog pointer 8 is rotated in a predetermined direction. At this time, as shown in FIG.
Also rotates with the analog pointer 8. In step S3, it is determined whether or not the proximity switch 15 is turned on. If it is determined in step S3 that the proximity switch 15 is on, the process proceeds to step S4. If it is determined that it is not in the ON state, the process returns to step S2, and the pulse motor 7 continues to rotate. In step S4, the pulse motor 7 is stopped to stop the rotation of the analog pointer 8. FIG. 4 shows this state. In this way, the position detection needle 1
When 4 approaches the proximity switch 15 by a certain amount or more, the rotation of the analog pointer 8 stops. Here, the analog pointer 8 stopped in step S4 does not completely instruct the zero scale 10A, and there is a “shift” between the zero scale 10A. Since this "deviation" has a constant value for each product, each unique value is checked in advance and this value is stored in the storage device 17 (FIG. 1) as a correction value. Step S5
Then, the motor driver 6 outputs a number of pulses corresponding to this correction value.
Is applied to the pulse motor 7 and the analog pointer 8 is stopped toward the zero scale 10A. Although the motor is stopped in step S4, it is not necessary to stop the motor as long as the pulse is output by the correction value stored in the storage device 17 after the proximity switch 15 is turned on.

As described above, in the material testing machine of the present embodiment, the proximity pointer 15 is used to stop the analog pointer 8 at a constant angle, and then the direction of the analog pointer 8 and the direction of the zero scale 10A are changed. Analog pointer 8
Is rotated to completely overlap the zero scale 10A. Therefore, unlike the conventional material testing machine, it is not necessary to visually grasp the direction of the analog pointer after the test or prior to the test and manually adjust to the zero scale.

It is theoretically possible to adjust the analog pointer to the zero scale without correcting the "deviation" by finely adjusting the mounting position of the proximity switch so that the "deviation" becomes zero. However, the detection distance of the proximity switch varies, and it is difficult to strictly control the mounting positions of the proximity switch and the position detection needle in the manufacturing process. Therefore, as in the above embodiment, if a method of allowing a certain amount of “deviation” and correcting it is adopted, an increase in the number of assembling steps can be prevented, or without using a proximity switch with high detection accuracy, Automatic zero adjustment of the pointer is possible at low cost.

In the present embodiment, the position detecting needle 14 that rotates in synchronization with the analog pointer 8 is used, but the approach of the analog pointer itself may be directly captured. For example, a reflection surface may be provided on the back surface of the analog pointer, and a light source and an optical sensor may be combined to detect that the analog pointer has rotated to a predetermined angle. In this case, it is desirable to provide a light transmitting portion at a predetermined position on the scale plate so that reflected light can be captured from the back side of the scale plate. Further, a magnetic sensor may be used for the same configuration.

In the present embodiment, the analog pointer 8 is rotated by a certain angle and then the analog pointer 8 is rotated by the amount of the deviation from the zero scale 10A. However, as shown in FIG. The encoder 21 may be provided to detect the absolute angle of the analog pointer 8. For example, if the absolute encoder 21 detects the absolute angle of the analog pointer 8 when the power switch of the material testing machine is turned on, the angle difference from the zero scale can be calculated. By giving the pulse motor 7 a number of pulses corresponding to this angle difference, the analog pointer can be adjusted to the zero scale. Since the speed reduction ratio of the pointer rotating mechanism in the present embodiment is greater than 1, the angle of the analog pointer 8 can be determined by detecting the angle of the pulse motor 7 by the absolute encoder 21.

[0016]

According to the first aspect of the present invention, after detecting that the analog pointer has rotated to a predetermined angle, the pulse motor is driven so as to eliminate the deviation from the initial angle. The angle of the analog pointer can be initialized without complicated operations. According to the invention described in claim 2, since the absolute angle of the analog pointer is detected by the angle detecting means and the pulse motor is driven by the angle corresponding to the difference from the initial angle, it is not complicated operation. The angle of the analog pointer can be initialized.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a material testing machine according to the present invention.

2A and 2B are diagrams showing an indicator of the material testing machine of the embodiment shown in FIG. 1, in which FIG. 2A is a diagram showing a surface of the indicator, and FIG.
Is a view showing the back surface of the indicator.

3A and 3B are diagrams showing a state in which an analog pointer of FIG. 2 is rotating, where FIG. 3A is a diagram showing a front surface of an indicator and FIG. 3B is a diagram showing a rear surface of the indicator.

4A and 4B are diagrams showing a state in which an analog pointer of FIG. 3 is stopped, where FIG. 4A is a diagram showing a front surface of an indicator and FIG. 4B is a diagram showing a rear surface of the indicator.

5 is a flowchart showing a sequence of the material testing machine according to the embodiment shown in FIG.

[Explanation of symbols] 2 controller 7 pulse motor 8 load analog pointer 14 Position detection needle 15 Proximity switch

─────────────────────────────────────────────────── ───Continued from the front page (56) References JP 62-113009 (JP, A) JP 61-240139 (JP, A) JP 6-129877 (JP, A) Actually published 64- 55433 (JP, U) Actual development Sho 64-2158 (JP, U) Actual development Flat 6-25745 (JP, U) Actual public flat 6-45222 (JP, Y2) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01N 3/00-3/62 JISST file (JOIS)

Claims (2)

(57) [Claims] 1. A material testing machine equipped with a display device for displaying a load applied to a specimen by an analog pointer, wherein the display device is a pulse motor for rotating the analog pointer, and the analog pointer has a predetermined absolute angle. Angle detection means for detecting the arrival of the signal and outputting a signal, and rotating the analog pointer by giving a continuous pulse to the pulse motor, when the signal is received, stop the continuous pulse, Control means for inputting a predetermined number of pulses corresponding to the relative angle between the angle of the analog pointer and the initial angle of the analog pointer to the pulse motor to rotate the analog pointer to the initial angle. Material testing machine. 2. A material testing machine equipped with a display device for displaying a load applied to a specimen by an analog pointer, wherein the display device detects a pulse motor for rotationally driving the analog pointer and an absolute angle of the analog pointer. And a predetermined number of pulses corresponding to the deviation between the absolute angle detected by the angle detection means and the initial angle of the analog pointer are input to the pulse motor, and the analog pointer is rotated to the initial angle. A material testing machine, comprising: