JP2006329794A - Load testing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a load testing machine capable of precisely detecting the progress of a change in load at every displacement to more reliably determine the quality of a test target. <P>SOLUTION: In S105, the change quantity of load W at every predetermined displacement ΔS is measured continuously and succeedingly. Subsequently, in S106, the peak point of the measured load W is detected. Next, in the decision of S109, the load is detected through a load meter in S110 when the displacement ΔS exceeds the peak point showing the maximum value of the load and the change quantity ΔW of the load reaches a predetermined value X (Yes) and set as a standard load value Wa. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a load testing machine that applies a predetermined load to a test object and measures a load displacement characteristic in which the load and the displacement are associated with each other.

  Conventionally, in order to evaluate the physical properties of the DUT, such as mechanical strength and elastic force, a predetermined load and displacement are applied to the DUT and the load and displacement are correlated to obtain a load displacement characteristic. It has been broken. As a load cell that applies load and displacement to the DUT, it is generally equipped with a terminal for applying tension or pressing force to the DUT, and the load transmitted through the terminal is detected and displayed via the load sensor. (For example, refer to Patent Document 1).

  A load meter is attached to the slide mechanism, and the load meter is slid along the direction of displacement of the DUT, so that a load and displacement can be applied to the DUT and the load and displacement can be correlated and measured. There is a load testing machine (see, for example, Patent Document 2). Further, in the load testing machine configured as described above, the displacement of the DUT is detected from the slide movement amount of the load cell.

In the load testing machine, the “load-displacement characteristics” of the DUT are measured, the maximum value of the load (peak value) and the average value of the load values for each of the plurality of displacements are detected, recorded, and Some are configured to display.
Japanese Patent Laid-Open No. 2001-208634 JP 7-45661 A

  However, according to the method of determining the “load-displacement characteristic” of the DUT by the average value of the load values for each of the plurality of displacements or the peak value of the load as in the conventional example, the load change for each displacement There was a risk that practical transition would not be sufficiently reflected and practical evaluation would be insufficient.

  Therefore, an object of the present invention is to provide a load testing machine that can accurately detect the transition of a load change for each displacement and can more reliably perform pass / fail judgment of the DUT.

  The invention according to claim 1, which has been made to achieve the above object, applies a load to the DUT, changes a relative distance between the load meter and the DUT, the load meter for measuring the load. A load mechanism for measuring a load displacement characteristic in which a load is applied to the DUT to displace the DUT and the load and the displacement are associated with each other. Change amount measuring means for continuously measuring the load change amount, maximum value detecting means for detecting the maximum value of the measured load, and the displacement exceeds a peak point indicating the maximum value of the load, the load And a standard load value detecting means for detecting the load when the amount of change reaches a predetermined value.

  According to the load testing machine of claim 1, the change amount measuring means for continuously and sequentially measuring the load change amount for each predetermined displacement, and the maximum value detecting means for detecting the maximum value of the measured load. And when the displacement exceeds a peak point indicating the maximum value of the load, and the amount of change in the load reaches a predetermined value, a standard load value detecting means that detects the load and sets it as a standard load value. Therefore, a more practical evaluation can be made by simply determining the “load-displacement characteristic” of the DUT by the average value or peak value of the load. That is, according to the load testing machine of the first aspect, in addition to the conventional characteristic evaluation, when the predetermined value is set to substantially zero and the displacement region where the amount of change in the load for each predetermined displacement is small is reached. What is necessary is just to detect a load as a standard load value. Thereby, according to the load testing machine of Claim 1, the characteristic evaluation which reflected transition of the load change for every displacement is attained.

  Next, the invention according to claim 2 is the load testing machine according to claim 1, wherein the displacement exceeds the peak point and the amount of change is predetermined within a predetermined range. An average load calculating means is provided for calculating an average load value by calculating a cumulative load by accumulating the load, and dividing the cumulative load by the number of data of the accumulated load.

  According to the load testing machine of claim 2, in a predetermined range in which the displacement exceeds the peak point and the amount of change is predetermined, the load for each predetermined displacement is accumulated to calculate the accumulated load, Displacement region in which the load change amount with respect to the displacement is stable because it includes the average load calculation means that calculates the average load value by dividing the load by the total number of load data. In this case, it is possible to detect the average load value and more reliably determine the quality of the DUT.

  Next, in the invention described in claim 3, the load displacement is expressed in each load test machine test according to claim 1 or 2, and the load displacement is expressed continuously for each displacement transition. Standard load displacement characteristic detection means for detecting the standard load displacement characteristic by storing the characteristic and calculating the average value of the plurality of stored load displacement characteristics is provided.

  According to the load testing machine of the third aspect, for each test, the load displacement characteristic for each test is stored by representing the transition of the load continuously for each transition of the displacement, and a plurality of stored load displacement characteristics are stored. Equipped with a standard load displacement characteristic detection means that calculates the average value and detects the standard load displacement characteristic. Compares the load displacement characteristic immediately after measurement with the standard load displacement characteristic, making it easy to judge the quality of the DUT. Can be done.

  Next, a fourth aspect of the present invention is the load tester according to the third aspect, further comprising deviation detecting means for comparing the load displacement characteristic with the standard load displacement characteristic and detecting the deviation. It is characterized by that.

  According to the load testing machine described in claim 4, since the load displacement characteristic and the standard load displacement characteristic are compared and the deviation detecting means for detecting the deviation is provided, the measurement with respect to the standard load displacement characteristic is performed for each test. The deviation of the values can be detected and the quality of the DUT can be determined with high accuracy.

  Next, the invention according to claim 5 is the load testing machine according to claim 4, further comprising display means for displaying the load displacement characteristics and the standard load displacement characteristics as continuous curves. And

  According to the load testing machine of the fifth aspect, since the display means for displaying the load displacement characteristic and the standard load displacement characteristic with respective continuous curves is provided, the comparison between the load displacement characteristic and the standard load displacement characteristic is visually observed. It can be done easily and the convenience can be improved.

  According to the load testing machine of the present invention, the change amount measuring means for continuously measuring the change amount of the load for each predetermined displacement, the maximum value detecting means for detecting the maximum value of the measured load, When the displacement exceeds the peak point indicating the maximum value of the load and the amount of change in the load reaches a predetermined value, a standard load value detecting means is provided which detects the load and sets it as a standard load value. As a result, the “load-displacement characteristic” of the DUT can be evaluated more practically than when it is simply determined by the average value or peak value of the load. That is, according to the load testing machine of the first aspect, in addition to the conventional characteristic evaluation, when the predetermined value is set to substantially zero and the displacement region where the amount of change in the load for each predetermined displacement is small is reached. What is necessary is just to detect a load as a standard load value. Thereby, according to the load testing machine of Claim 1, the characteristic evaluation which reflected transition of the load change for every displacement is attained.

  Further, according to the load testing machine of the present invention, the cumulative load is calculated by accumulating the load for each predetermined displacement within a predetermined range in which the displacement exceeds the peak point and the amount of change is determined in advance. The average load calculation means that calculates the average load value by dividing the total load data is included. By detecting the average load value, the “load-displacement characteristic” of the DUT can be detected with high accuracy, and the quality of the DUT can be determined more reliably.

  Further, according to each load tester test of the present invention, the load displacement characteristic immediately after measurement can be compared with the standard load displacement characteristic for each test, and the quality of the test object can be accurately determined.

  Next, an embodiment of the load tester of the present invention will be described with reference to the drawings. 1 is an external view showing the external appearance of the load tester of the present invention, FIG. 2 is a block diagram showing a control system of the load tester, and FIGS. 3 to 5 are for explaining measurement modes provided in the load tester. FIG. 6 is a load displacement characteristic diagram and a standard load displacement characteristic diagram in the same example.

  As shown in FIG. 1, the load testing machine 1 includes a load meter 2 that applies a load to the DUT and measures the load, and a slide mechanism that changes the relative distance between the load meter 2 and the DUT. The moving device 3, the control device 5 for operating the moving device 3 and the load meter 2, and the interface connection cable 11 for performing data communication between the control device 5 and a personal computer (not shown) are provided.

  The load meter 2 includes a power key 2a, a liquid crystal display 2b for displaying the measurement result, a zero point calibration key 2s for calibrating the measurement value to zero, and a peak output key for instructing output of a peak value of the load read continuously. 2d, a unit switching key 2e for switching the unit of load (for example, Kgf or N), a terminal 2f for applying tension or pressing force to the DUT, and the like. Further, the load cell 2 has a built-in drive circuit (reference numeral 2g in FIG. 2) for controlling the measurement operation based on the command signals from the respective keys described above, and the load cell 2 and the control device 5 are connected to the communication cable. (Not shown).

  The moving device 3 is rotatably supported via a support column 3f, a bearing 3c and a coupling 3b, and a bearing 3c and a coupling 3b provided upright on the control device 5, and a spiral screw is formed along the outer periphery. A screw 3a, a holder 3g that is fitted to the screw 3a via a female screw (not shown), slides along the axial direction of the screw 3a as the screw 3a rotates, and fixes the load meter 2; Etc.

  Further, one end of the screw 3a is connected to a rotating shaft of a motor provided in the control device 5 through a coupling 3b. And the moving apparatus 3 is comprised so that the rotation operation | movement of a motor may be converted into the linear motion which slides the load cell 2 up and down via the screw 3a and the holder 3g. The function of the slide mechanism of the present invention is expressed by the motor, the support 3f, the screw 3a, the bearing 3c, the coupling 3b, the holder 3g, and the like provided in the control device 5.

  Next, the control device 5 includes an operation panel 8 for an operator to operate the measurement operation and slide operation of the load cell 2. The operation panel 8 has speed setting knobs 8b and 8c for setting the sliding speed of the load cell 2, a direction command key 8d for instructing the sliding direction of the load cell 2 upward (arrow U direction), and the sliding direction of the load cell 2 downward. A direction command key 8e for commanding in the direction of arrow D, a measurement mode selection key 8f for setting each measurement mode to be described later, a liquid crystal display 8k and a numerical value input key 8m for setting operation speed, displacement, load, etc. in the measurement mode, 8n, a start key 8p for instructing start of the measurement operation based on the set measurement mode, a stop key 8h for instructing stop of the measurement operation, and the like are provided.

  Next, as shown in FIG. 2, the load testing machine 1 includes a control system 100 that controls the operation of the moving device 3 and the load cell 2. The control system 100 is configured as a microcomputer centered on the CPU 21, ROM 22, and RAM 23, and the CPU 21 executes processing of each function using the ROM 22, RAM 23, and the like based on a command signal input from the operation panel 8.

  The control system 100 counts the elapsed time and outputs a signal representing the elapsed time to the CPU 21. The motor control unit 24 outputs a drive signal to the motor 25 based on the output signal from the CPU 21. A motor 25 that rotates based on a drive signal input from the unit 24, a moving device 3 that converts the rotational force of the motor 25 into a linear motion and moves the load cell 3 in the directions of arrows U and D in FIG. It is constituted by.

  The load cell 2 applies a pressing force or tensile force to the DUT, and transmits the load to the load cell 2d. The load cell 2r and the load cell 2r generate an electrical signal corresponding to the load transmitted through the terminal 2f. The drive circuit 2g etc. which convert the electric signal produced | generated by (1) into a digital signal and output to CPU21 are provided. The drive circuit 2g is based on the command signal input from the power key 2a, zero point calibration key 2s, peak output key 2d, unit switching key 2e, etc., and the command signal input from the CPU 31. 2 is controlled.

  The control system 100 also includes an analog voltage output unit 31 that outputs measured loads and displacements as voltage signals to an interface 30 that serially transmits and receives data between the CPU 21 and an external personal computer, such as a pen recorder. A pair of upper and lower limit switches 32a and 32b that operate at a predetermined slide position of the load cell 2 and output a stop signal to stop the slide operation to the CPU 21, an operation panel 8 for operating the operator to send a command signal to the CPU 21, etc. It is constituted by. In addition, the personal computer is configured to output data in which the load and the displacement are associated with each displacement via the interface 30 so that the load displacement characteristic can be displayed as a continuous curve. The function of the display means of the present invention is expressed by the interface 30 and the personal computer.

  Next, the load testing machine 1 is provided with three measurement operation modes that operate according to a command signal input from the operation panel 8 or the like. Hereinafter, the measurement operation mode will be described with reference to FIGS. In this processing procedure, the ROM 22 is provided with the program, and the CPU 21 executes each processing using the program.

  First, this procedure starts when an activation signal (start signal) is input to the CPU 21 via the operation panel 8.

  Next, in S101 of FIG. 3 (S represents a step), one of the measurement modes 1, 2, and 3 is selected. The measurement modes 1, 2, and 3 are selected based on a measurement mode command signal input in advance by the operator via the operation panel 8.

  Next, when the measurement mode 1 is selected in S101, the process proceeds to S102. In S102, a predetermined displacement ΔS for measuring the load continuously for each predetermined displacement is set, and in S110, the standard load is set. A predetermined value X is set as a parameter for detecting the value Wa, and then the process proceeds to S103.

  Next, in S103, the load meter 2 starts to start and slides, and then proceeds to S104. Next, in S104, when the slide amount of the load cell 2 reaches a predetermined displacement ΔS, the load W is detected via the load cell 2, and the process proceeds to S105. Next, in S105, the load W detected in S104 and the load change amount (ΔW / ΔS) accompanying the displacement of ΔS are stored in the RAM 23.

  Next, in S106, it is determined whether or not a load peak point (reference symbol P in FIG. 6) has been detected based on the transition of the load change amount (ΔW / ΔS). In this embodiment, it is programmed to detect the boundary where the load change amount (ΔW / ΔS) shifts from increase to decrease as a peak point. The function of the maximum value detecting means in the present invention is expressed in S106.

  Next, if no peak point is detected in S106 (No), the process returns to S104 and S104 to S106 are repeated. If a peak point is detected in S106, the process proceeds to S107.

  Next, in S107, the load W associated with the next displacement of ΔS is measured, and then the process proceeds to S108. In S108, the load W is stored in the RAM 23, and the change amount (ΔW / ΔS) of the load W is detected and the RAM 23 is detected. And then move to S109.

  Next, in S109, it is determined whether or not the load change amount (ΔW / ΔS) is smaller than the predetermined value X set in S102, and the load change amount (ΔW / ΔS) is not smaller than the predetermined value X (No ), The process returns to S107 and repeats S107 to S109. When the load change amount (ΔW / ΔS) is smaller than the predetermined value X (Yes), the process proceeds to S110, and in S110, the measurement is performed in S107. The load is detected as the standard load value Wa, stored in the RAM 23, and then the process proceeds to S111. The function of the change amount measuring means in the present invention is expressed by S105 and S108. Moreover, the function of the standard load value detection means in the present invention is expressed by S109 and S110.

  Next, in S111, it is determined whether or not the limit switch 32a or the limit switch 32b is turned on. If the limit switches 32a and 32b are not turned on (No), the process waits until the limit switches 32a and 32b are turned on. If the limit switches 32a and 32b are turned on (Yes), the process proceeds to S112.

  Next, in S112, the load W detected in S104, the load W detected in S107, and the like are stored in the ROM 22 in association with the displacement, and the standard load value Wa detected in S110 is stored in the ROM 22, and this processing procedure ends. To do.

  Next, when the measurement mode 2 is selected in S101, the process proceeds to S201 in FIG. 4, and in S201, a predetermined displacement ΔS when the load W is continuously measured for each predetermined displacement is set. At the same time, predetermined range values X1 and X2 that are parameters for calculating the average load Wd are set in S211, and then the process proceeds to S202.

  Next, in S202, the load meter 2 starts to start and slides, and the process proceeds to S203. Next, in S203, when the slide amount of the load cell 2 reaches a predetermined displacement ΔS, the load of the load cell 2 is detected, and the process proceeds to S204. Next, in S204, the load W detected in S203 and the load change amount (ΔW / ΔS) accompanying the displacement of ΔS are stored in the RAM 23.

  Next, in S205, whether or not a peak point (reference symbol P in FIG. 6) has been detected is determined based on the transition of the load change amount (ΔW / ΔS). In this embodiment, it is programmed to detect a boundary point where the load change amount (ΔW / ΔS) decreases from an increase as a peak point.

  If no peak point is detected in S205 (No), the process returns to S203 and repeats S203 to S205. On the other hand, if a peak point is detected in S205, the process proceeds to S206.

  Next, in S206, it is determined whether or not the load change amount (ΔW / ΔS) is within the predetermined range value (range from X1 to X2) set in S201, and is not in the predetermined range X1 to X2 (No). In this case, the process returns to S203, and S203 to S206 are repeated. On the other hand, if it is within the predetermined range X1 to X2 (Yes), the process proceeds to S207.

  Next, in S207, when the sliding amount of the load cell 2 reaches a displacement of ΔS, the load W is detected via the load cell 2, and in S208, the load W is stored in the RAM 23 and the displacement of ΔS is detected. The amount of change (ΔW / ΔS) of the load W accompanying this is detected and stored in the RAM 23.

  Next, in S209, the load for each predetermined displacement ΔS is accumulated to calculate the cumulative load Wt, and then the process proceeds to S210. When the load W corresponds to the first ΔS, the load W having the first value is the cumulative load Wt.

  Next, in S210, it is determined whether or not the load change amount (ΔW / ΔS) is out of the predetermined range (X1 to X2) set in S201, and is in the predetermined X1 to X2 range (No). In this case, the process returns to S207, and S207 to S210 are repeated. On the other hand, if it is out of the predetermined range of X1 to X2 (Yes), the process proceeds to S211.

  Next, in step 211, the cumulative load Wt calculated in S209 is divided by the cumulative load data number N to calculate an average load Wd.

  That is, due to S206 to S211, the displacement exceeds the peak point of the load, and ΔW / ΔS is a load W having a predetermined range (a range from X1 to X2) (a load in a range from X1 to X2 shown in FIG. 6). Are sequentially accumulated, and the average load Wd is calculated by dividing the accumulated load Wt by the number N of accumulated load data. The function of the average load calculation means of the present invention is expressed by S206 to S211.

  Next, in S212, it is determined whether or not the limit switch is turned on. If the limit switch is not turned on (No), the process waits until the limit switch is turned on and the limit switch is turned on (Yes). In the case, the process proceeds to S213.

  Next, in S213, the load W and the like detected in S203 and S207 are stored in the ROM 22 in association with the displacement S, and the average load value Wd calculated in S211 is stored in the ROM 22, and this processing procedure ends.

  Next, when the measurement mode 3 is selected in S101, the process proceeds to S301 in FIG. 5, and in S301, a predetermined displacement ΔS for measuring the load continuously for each predetermined displacement is set. Thereafter, the process proceeds to S302. Next, in S302, the load meter 2 starts to start and slides, and then proceeds to S303.

  Next, in S303, when the slide amount of the load cell 2 reaches a predetermined displacement ΔS, the load W is detected via the load cell 2, and then the process proceeds to S304.

  Next, in S304, the load W detected in S303 is added to the load Wo obtained in the measurement of the previous sample at the same displacement to obtain the cumulative load Wt, and the cumulative load Wt is calculated as the cumulative load Wt. Dividing by the number of data N, the average load value Wd is calculated. That is, the loads at the same displacement of a plurality of test objects are sequentially accumulated to calculate the average load value Wd.

  Next, in S305, a deviation Wdv between the average load value Wd calculated in S304 and the load W detected in S303 is calculated, and then the process proceeds to S306.

  Next, in S306, it is determined whether or not the limit switch is turned on. If the limit switch is not turned on (No), the process returns to S303, and S303 to S306 are repeated, and the limit switch is turned on (Yes). In step S307, the load value W detected in step S303, the average load value Wd calculated in step S304, the load deviation Wdv calculated in step S305, and the like are stored in the ROM 22.

  Next, the process proceeds to S308, where it is determined whether or not there is an object to be measured. If yes (Yes), the process returns to S302 and repeats S302 to S307. If not (No), this processing procedure is performed. Exit. Then, by repeating S302 to S307, the load displacement characteristics (curve M in FIG. 6) for each test of a plurality of test objects are stored, and an average value of the stored plurality of load displacement characteristics is calculated. The standard load displacement characteristics (curve SD in FIG. 6) are stored in the ROM 22 and output to the personal computer via the interface 30. The load displacement characteristics and the standard load displacement characteristics are continuously obtained via the personal computer. Display as a curve. When the predetermined displacement S1 and a signal for obtaining the deviation are input via the operation panel 8 with the load displacement characteristic and the standard load displacement characteristic displayed, the deviation Wd calculated in S305 and stored in S307 is input. The deviation Wd corresponding to S1 is output.

  Below, the effect of the load testing machine 1 of the Example which has the said structure is described.

  According to the load testing machine 1 described in the present embodiment, as shown in FIG. 3, the load change amount ΔW for each predetermined displacement ΔS is continuously and sequentially measured in S105, and then measured in S106. When the displacement exceeds the peak point P indicating the maximum load value and the amount of change in the load reaches a predetermined value X in S109, the load W is detected. Can be used as the standard load value Wa, so that the "load-displacement characteristic" of the DUT can be determined simply by the average value or peak value of the load. Further practical evaluation becomes possible.

  Further, according to the load testing machine 1 described in the present embodiment, as shown in FIG. 4, in a predetermined range in which the displacement S exceeds the peak point P and the amount of change is determined in advance from S206 to S209. Accumulated load Wt is calculated by accumulating the load for each predetermined displacement, and the average load Wd can be calculated by dividing the accumulated load Wt by the accumulated load data number N. In the displacement region (the range of X1 to X2 in FIG. 6) in which the load change amount with respect to the displacement S is stable without including the point P, the “load-displacement characteristic” of the DUT is detected by detecting the average load Wd. Can be detected with high accuracy, and the quality of the DUT can be determined more reliably.

  Further, according to the load testing machine 1 of the present embodiment, as shown in FIG. 5, the load displacement characteristic for each test is stored, and the average value Wd of the plurality of load displacement characteristics stored in S304 is calculated, Since the standard load displacement characteristic can be obtained, the load displacement characteristic immediately after the measurement can be compared with the standard load displacement characteristic, and the quality of the test object can be easily determined.

  In addition, according to the load testing machine 1 of the present embodiment, the load displacement characteristic for each test is compared with the standard load displacement characteristic in S305, and the deviation is detected. The determination can be performed with high accuracy.

  As mentioned above, although one Example of this invention was described, this invention is not limited to the said Example, It can take various aspects. For example, in this embodiment, the standard load displacement characteristic and the deviation Wdv with respect to the load displacement characteristic for each test are obtained for each ΔS from S303 to S305 in FIG. 5, but as shown in S201 in FIG. A predetermined range X1 to X2 may be set, the deviation Wdv in the range may be accumulated, and the accumulated deviation may be detected by averaging.

It is an external view showing the external appearance of the load testing machine in one Example of this invention. It is a block diagram showing the control system of the load testing machine in the Example. It is explanatory drawing of the measurement mode with which the load testing machine was equipped in the Example. It is explanatory drawing of the measurement mode with which the load testing machine was equipped in the Example. It is explanatory drawing of the measurement mode with which the load testing machine was equipped in the Example. It is a load displacement characteristic figure detected in the example, and a standard load displacement characteristic figure.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Load tester, 2 ... Load meter, 2a ... Power key, 2b ... Liquid crystal display part, 2d ... Peak output key, 2e ... Measurement unit switching key, 2f ... Terminal, 2s ... Zero point calibration key, 2r ... Load cell, DESCRIPTION OF SYMBOLS 3 ... Moving device, 3a ... Screw, 3b ... Coupling, 3c ... Bearing, 3d ... Test object mounting base, 3g ... Holder, 4 ... Reading device, 5 ... Control device, 8 ... Operation panel, 8b, 8c ... Speed Setting knob, 8d, 8e ... Direction command key, 8f ... Measurement mode selection key, 8k ... Liquid crystal display, 8m, 8n ... Numerical input key, 8p ... Start key, 8h ... Stop key, 11 ... Interface connection cable, 21 ... CPU 22 ... ROM, 23 ... RAM, 24 ... motor control unit, 25 ... motor, 30 ... USB interface, 31 ... analog voltage output unit, 32a, 32b ... limit Switch, 33 ... time counter.

Claims (5)

A load cell that applies a load to the DUT and measures the load;
A slide mechanism for changing a relative distance between the load cell and the DUT,
A load testing machine that applies a load to the DUT to displace the DUT and measures a load displacement characteristic that associates the load with the displacement,
A change amount measuring means for continuously and sequentially measuring a load change amount for each predetermined displacement;
A maximum value detecting means for detecting the maximum value of the measured load;
When the displacement exceeds a peak point indicating the maximum value of the load, and the amount of change in the load reaches a predetermined value, a standard load value detection unit that detects the load and sets it as a standard load value;
A load testing machine characterized by comprising: In a predetermined range in which the displacement exceeds the peak point and the amount of change is predetermined, the load for each predetermined displacement is accumulated to calculate a cumulative load, and the cumulative load is divided by the total number of load data. And an average load calculating means for calculating the average load value.
The load testing machine according to claim 1, wherein: Standard load that detects the standard load displacement characteristic by calculating the average value of the plurality of stored load displacement characteristics by storing the load displacement characteristics by representing the transition of the load continuously for each displacement transition for each test. A displacement characteristic detecting means;
The load testing machine according to claim 1 or 2, wherein Comparing the load displacement characteristics with the standard load displacement characteristics, and comprising a deviation detection means for detecting the deviation,
The load testing machine according to claim 3, wherein:   The load testing machine according to claim 4, further comprising display means for displaying the load displacement characteristic and the standard load displacement characteristic with continuous curves.

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