JPH0456253B2 - - Google Patents

Description

Detailed Description of the Invention (a) Field of Industrial Application The present invention is applicable to powder molded products such as pharmaceutical tablets, sintered parts for ceramics, and foods, as well as to compressed or tensile products such as films, tapes, and textile products. This invention relates to a device for measuring breaking strength.

(b) Conventional technology Conventionally, the mainstream of devices for measuring the breaking strength of powder molded products, etc. as described above has been one that applies a compressive or tensile load to a sample and measures the load value at the time of sample fracture. , as the loading method, weight type,
There are spring type and compressed air type. However, in any of these conventional devices, it cannot be said that the reproducibility of the measured value of breaking strength is necessarily good. In other words, in order to measure the destructive load with good reproducibility in this type of destructive test, the speed of the load applied to the sample, that is, the loading speed, must be below a predetermined speed, and the initial load applied to the sample must be constant. Although it has been found that it is necessary to do so, conventional devices have been uncertain, especially regarding the former condition.

(C) Objective The present invention has been made in view of the above, and its main objective is to provide a reproducible motion sickness fracture strength measuring device that can reliably apply a load to a sample at a preset loading rate. It's about doing.

Another object of the present invention is to be able to accurately and automatically detect the load at the time of sample failure, and further to provide a load detection section that measures the failure load of the sample with a load of a fraction of the failure load to several tens of tens of times. It is an object of the present invention to provide a breaking load measuring device that can use a detector with a weighing capacity of about 1/2 and has a wide measuring range.

(D) Structure The breaking strength measuring device of the present invention comprises two Roberval mechanisms disposed close to each other in the vertical direction, and a sample holder provided opposite to each other on the connecting rods of the Roberval mechanisms. , a load unit that applies a load to one lever of the Roberval mechanism via an elastic body, a cantilever connected to the lever of the other Roberval mechanism via a connecting rod, and a load unit that applies a load to the lever of the Roberval mechanism on the other hand, and a cantilever that resists displacement of the cantilever. A load detection section that generates a force that makes the displacement zero and detects the load acting on the cantilever, and a load detection section that controls the loading speed by the load section and collects data from the load detection section every moment to determine the maximum value. The present invention is characterized by comprising an arithmetic control section that measures the breaking load of the sample held in the sample holding section by detecting the value.

(e) Examples Examples of the present invention will be described below based on the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention. In addition,
In this example, an example will be described in which a compressive load is applied to the sample W to cause compressive fracture.

Levers 2a and 2 are rotatably supported on four fulcrums provided on the axis of column 1, respectively.
b, and one ends of 3a and 3b are pin-joined by connecting rods 2c and 3c, respectively. The levers 2a and 2b, the connecting rod 2c, and the column 1 are configured to always remain parallel to each other, and constitute a first roberval mechanism 2. In addition, levers 3a and 3b, connecting rod 3c and column 1
are similarly constructed so as to always remain parallel to each other, and thereby the second roberval mechanism 3
It consists of Each lever 2a, 2b, 3a, 3
The distances from each fulcrum of b to the joint points with the connecting rods 2c and 3c are equal, and the connecting rods 2c and 3c are provided with sample holding parts 4 and 5, respectively, at positions facing each other.

The lever 2a of the first Roberval mechanism 2 extends to the opposite side of the connecting rod 2c across the fulcrum of the column 1,
One end of a tension coil spring 6 is attached.
The other end of the tension coil spring 6 is fixed to a slider 8 that is slidable on a guide 7, and the slider 9
The pulley 9 is fixed on the drive shaft of the motor 9.
A steel wire 10 to be wound up is attached to a. Further, the lever 2a is provided with an adjustment mechanism for finely adjusting its inclination. That is, an adjustment rod 11 having a male thread cut into one end is pin-jointed to the lever 2a, and the male thread is screwed into a cap nut 7a fixed to one end of the guide 7 described above. The guide 7 is rotated by pressing the handle 12b against the compression coil spring 12c via a friction wheel 7b provided at the other end and a friction wheel 12a provided on the adjustment shaft 12. It is rotated, and the inclination of the lever 2a can be changed by the cap nut 7a and the male thread of the adjustment rod 11. Note that in a normal state, the friction wheel 12a is disengaged from the friction wheel 7b due to the action of the compression coil spring 12c.

The lever 3a of the second Roberval mechanism 3 extends to the opposite side of the connecting rod 3c across the fulcrum of the column 1 to form a long hole A, and one end of the connecting rod 14 is inserted into the long hole A by a screw 13a. It is fixed. Continuation 14
The other end is fixed to a long hole B formed in the cantilever 15, which is rotatable around the pin 15a, by a screw 13b. The tip of the cantilever 15 is placed on a tray 16a of an electronic balance 16.

The electronic balance 16 is an electromagnetic balance type balance, which generates an electromagnetic force in the opposite direction that is equal to the load so that when a load acts on the tray 16a, the displacement of the tray 16a becomes zero. can be measured. The electronic balance 16 uses a CPU
17, and the CPU 17 also has a ROM 18 in which programs are written, and an electronic balance 1.
RAM1 that sequentially stores load data etc. from 6
9, a display 20 for displaying information based on commands, a keyboard 21 for providing various initial values and commands, and an output port 22 for supplying control signals to the motor 9 are connected. CPU17 is ROM
Based on the program written in the electronic balance 18, load detection data by the electronic balance 16 is collected every few tens of microseconds, a predetermined number of the latest data is stored in the RAM 19, and its peak value is detected by the method described later. It is configured like this.

Next, we will discuss the effect.

First, the sample W is set between the sample holders 4 and 5, and the handle 12b is pressed and rotated to release the lever 2a.
Finely adjust the inclination of the sample W and apply a very slight initial load to the extent that no space is created between the sample W and the sample holders 4 and 5. At this time, a force corresponding to the load acts on the tray 16a of the electronic balance 16, but that value is erased as a tare value using the keyboard 21, and the display 20 is made to display zero. next,
When the load speed written in the ROM 18 is called or the load speed is set using the keyboard 21 and a drive command is given to the motor 9, a control signal corresponding to the load speed is sent to the output port 22 of the motor 9. The steel wire 10 is wound up at a predetermined constant speed. As a result, the slider 8 is displaced downward along the guide 7 and pulls the tension coil spring 6 downward. As a result, the lever 2a rotates clockwise around the fulcrum of the column 1 and presses the sample W via the sample holder 4, and the lever 3a,
The cantilever 15 is connected to the pin 15a via the connecting rod 14.
However, since an electromagnetic force acts on the tray 1a of the electronic balance 16 such that its displacement becomes zero, the above-mentioned members are not substantially displaced, and the tension coil spring 6 is extended, and a force proportional to the displacement of the tension coil spring 6 is applied to the lever 2a according to Hook's law. Therefore, the steel wire 10 of the motor 9 is included in the sample W.
A compressive load F is applied at a predetermined loading rate proportional to the winding speed.

The compressive load F is measured by the electronic balance 16 via the lever 3a, the connecting rod 14, and the cantilever 15. That is, when the dimensions of each part of the lever 3a and the cantilever 15 are configured as shown in FIG. 1, the force f acting on the receiving plate 16a is as follows: f=F·l/m·p/n (1). Here, m and p are variable depending on the mounting position in the long holes A and B of the connecting rod 14, so equation (1) can be used to express m' and p' as follows: is the value when installed at the leftmost position, and α
If is the distance from that position to the actual mounting position of the connecting rod 14, then f=F・(l/m′+α・p′−α/n)……(2) can be generalized. can. By inputting α prior to the test, the compressive load F can be immediately calculated from the force f acting on the electronic balance 16 and displayed on the display 20.

Now, the load detection data from the electronic balance 16 is
The data is collected by the CPU 17 and stored in the RAM 19, and the latest data _d0 is always compared with the data _d3 collected three times before. While d ₀ − _{d 3} ≧0 holds, it is determined that the applied load is increasing, and d ₀ − _{d 3}
When the condition <0 occurs, d ₀ - d ₁ < 0 and d ₀ - d ₂ < 0 are established using data d ₁ collected immediately before d 0 and data _{d 2} collected immediately before that. Check if it is true, and if it is true, data d ₃
is determined to be the maximum value of the load, and issues a stop command to the motor 9. That is, when the load F acting on the sample W gradually increases due to the drive of the motor 9, and when the load F reaches the breaking load of the sample and the sample is destroyed, the force f acting on the electronic balance 16 rapidly approaches zero; The maximum value of the load acting on the sample W, that is, the breaking load, is captured by the data monitoring described above. During this time, the load F actually acting on the sample W is calculated using equation (2), and the display 2
0 is displayed, but when the maximum value of the applied load is detected, that value is held and the breaking load is displayed.

In the above embodiment, an example was described in which a compressive load is applied to the sample W to measure the compressive fracture load. , the tension coil spring 6 is changed to a compression coil spring, and the motor 9 moves the spring upward in FIG. For example, by driving a rack or the like, a tensile load can be applied to the sample and the tensile breaking strength can be measured. Alternatively, the tension coil spring 6 can be connected to the second Roberval mechanism 3.
Even if the lever 3a is set, the tensile fracture test can be performed.

(f) Effects As explained above, according to the present invention, a load is applied to a sample by two upper and lower Roberval mechanisms, and a load detection unit using a zero position method, such as an electromagnetic force balance type electronic balance, is used. Since the Roberval mechanism was constructed so as not to be substantially displaced, it was ensured that only vertical loads were applied to the sample. Furthermore, the load applied to the sample was configured to be applied via an elastic body by a motor controlled to a preset rotation speed, so that the predetermined load speed could be reliably maintained based on Hook's law. This makes it possible to conduct destructive tests with extremely high reproducibility.

Further, since the breaking load of the sample is applied to the load detection section under a predetermined leverage ratio, the measurement range of the load detection section may be small. Furthermore, by configuring the connecting rod 14 that connects the lever 3a and the cantilever 15 to be movable within the elongated holes A and B, it can act on the applied load and the load detection section at an arbitrary lever ratio according to the strength of the sample. The size of the load to be measured can be set, greatly increasing the measurement range.

Furthermore, by providing an adjustment mechanism for finely adjusting the inclination of the lever 2a, the initial load of the sample can be arbitrarily set, and the test can be started in the best condition without overloading or the like.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an embodiment of the present invention, and FIG. 2 is an enlarged view showing a sample holding section of another embodiment of the present invention. 2...first roberval mechanism, 2a, 2b...
Lever, 2c...Connection rod, 3...Second Roberval mechanism, 3a, 3b...Lever, 3c...Connection rod, 4, 5...Sample holder, 6...Tension coil spring, 7...Guide , 8...Slider, 9...Motor, 9a...Pulley, 11...Adjustment rod, 12...
Adjustment shaft, 12b...handle, 14...connection rod, 1
5...Cantilever, 16...Electronic balance, 17
...CPU, 18...ROM, 19...RAM, 2
0...Indicator.

Claims (1)

[Scope of Claims] 1. Two Roberval mechanisms disposed close to each other in the vertical direction, a sample holding section provided facing each other on connecting rods of the Roberval mechanisms, and one of the Roberval mechanisms. A load unit that applies a load to the lever of the lever via an elastic body, a cantilever connected to the lever of the other Roberval mechanism via a connecting rod, and a force that resists the displacement of the cantilever and makes the displacement zero. A load detection unit generates a load and detects the load acting on the cantilever, and controls the loading speed by the load unit, and collects data from the load detection unit every moment and detects the maximum value. A breaking strength measuring device comprising a calculation control unit that measures the breaking load of a sample held in a sample holding unit. 2. The connection position between the lever of the other Roberval mechanism by the connecting rod and the cantilever is variable, and the ratio of the load acting on the load detection section to the load acting on the sample can be set arbitrarily. A breaking strength measuring device according to claim 1, characterized in that: 3. According to claim 1 or 2, the means for adjusting the inclination of the lever of one of the Roberval mechanisms is configured to arbitrarily set and obtain the initial load acting on the sample. Breaking strength measuring device.