JPH0120681Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a calorific value measuring device for rubber samples, and more specifically, to ASTMD-623-, which is known as a calorific value measuring device for evaluating the heat generating characteristics of viscoelastic bodies such as rubber. Standardized to 67MethodA
This relates to improvements to the Goodrich Flexometer (hereinafter referred to as a calorific value measuring device for rubber samples).

Goodrich Flexometer
Flexometer), a device for measuring the calorific value of rubber samples, was developed in 1937 by E.T.
It was released as a heat-generating fatigue testing device by ASTMD Lessig, and later incorporated into ASTM standards and various improvements were made, and even now ASTMD-
This is a device widely used as 623MethodA.

The structure and operation of this device will be briefly explained with reference to FIG. 1, and the problems of this device will also be explained.

FIG. 1 is a perspective explanatory diagram showing an outline of a calorific value measuring device for rubber samples currently in use, and 1 indicates a frame of the main body of the test device, and the frame includes an electric motor (not shown) and a V-pulley. (not shown), the eccentric wheel 2 converts the rotational movement into vertical movement. A cylindrical sample 3 is sandwiched between an upper sample anvil 4 and a lower anvil 5, and the center of the lower anvil 5 is thermally insulated with an ebonite plate and has a thermocouple contact at the center to record the amount of heat generated by the sample 3. It is output to. First, a compressive load is applied to sample 3, and this load is applied using a balance system. The fulcrum 7 of the lever arm 6 of the balance is a knife edge, and when a load 8 is applied, the lever arm 6
pushes up the lower anvil 5, which is connected to the tilting lever arm 6 with a screw 10, so that a compressive load is applied to the sample 3. A differential transformer 9 is connected to the rear of the lever arm 6, and when the lever arm 6 is tilted, the amount of displacement, that is, the amount of change in compression of the sample, is converted into the amount of rotation by a reversible motor 11 corresponding to the amount of change. , is transmitted to the worm gear 13 and worm wheel 14 by the electromagnetic clutch 12, and rotates the helical gear 15. The screw 1 for the lower anvil 5 is rotated by the rotation of the helical gear 15.
0 moves up and down, and the lever arm 6 is controlled so that it is always kept horizontal.

After a compressive load is applied to the sample 3, the eccentric foil 2 is rotated to move the connecting slot 16 up and down.
The upper anvil 4 is moved up and down by the upper beam 17 connected to the upper beam 17, and compressive strain is repeatedly applied to the sample 3. Similarly, the amount of compression change set by the sample 3 due to repeated compression strain is caused by the lower anvil 5 moving up and down,
It operates so that the lever arm 6 becomes horizontal.

Further, the amount of compression change in the sample 3 is determined by a potentiometer 18 coaxial with the worm gear 13, which outputs the strain amount of the sample 3 to a recorder.

Further, in this testing machine, the repeated compression speed applied to the sample 3 is fast, so when the sample 3 undergoes compression vibration, the lower anvil 5 also vibrates, causing the lever arm 6 to vibrate, making it impossible to apply an accurate compression load. To prevent this, counterbalances 19 and 19' are added to the front and rear of the lever arm 6 to increase the inertia of the lever arm 6, thereby reducing vibration. Therefore, a compressive load applied to the sample 3 results in a load 8 being applied onto this counterbalance 19.

However, even if the counterbalance 19 is used, when repeatedly applying compressive strain to the sample 3 or when the test is finished, the compression speed becomes low and a resonance point appears between the compression speed and the inertia of the lever arm 6. There is a region where 6 vibrates violently. When the compression speed passes through this region repeatedly,
Especially at the end of the test, the compression speed slowly decreases and the lever arm 6 vibrates violently for a long time.
A hole is made in the center of the hole, and a hole 6a is also made in the lever arm 6 on the axis of the hole, and a lever arm vibration prevention taper pin 21 is inserted into the hole 6a to prevent violent vibration of the lever arm 6. When the taper pin 21 is inserted, the lever arm 6 does not vibrate, but at the same time no compressive load is applied to the sample 3, so the taper pin 21 is naturally pulled out except before and after the start of the test.

This testing machine was able to automatically detect the calorific value of sample 3 and the set amount of sample 3 during the test, as described above, and record it automatically on a recorder, etc. Inserting and pulling out work has traditionally been done by workers.

This operation of inserting and pulling out the taper pin 21 is an important operation to prevent the sample 3 from protruding from the lower anvil 5, making the test impossible or causing the testing machine itself to malfunction. Therefore, because this work is done manually, the operator must be near the testing machine during the test, and there are major drawbacks, such as the fact that the test machine cannot be completed during the night because it is operated all night. Was.

An object of the present invention is to provide an excellent apparatus for measuring the calorific value of a rubber sample, which can automatically prevent the vibration of the lever arm described above at a required time.

In order to achieve the above object, the present invention applies a predetermined compressive load to a sample attached to a predetermined position via a lever arm, repeatedly applies a constant amount of compressive strain, and then A pin support stand is arranged in front of the fulcrum of the lever arm and near the sample, and the lever arm has a hole through which a taper pin for preventing vibration of the lever arm can be inserted and removed. In the apparatus for measuring the calorific value of a rubber sample, a cylinder is provided on the side of the pin support for inserting and removing a taper pin into a hole formed in the pin support and the lever arm, and , a position checker is provided to detect whether the taper pin is inserted into or removed from the hole, and based on a signal from the position checker, a solenoid valve provided on a hose connecting the cylinder and the working pressure fluid source is switched. The gist is that the working pressure fluid is controlled and supplied to the telescopic pressure chamber of the cylinder.

Hereinafter, the present invention will be explained in detail by way of examples with reference to the drawings.

FIG. 2 is an explanatory front view showing an apparatus for measuring the calorific value of a rubber sample according to an embodiment of the present invention, and FIG. 3 is an explanatory side view of the same.

In the figure, G is a calorific value measuring device for a rubber sample according to an embodiment of the present invention, in which a predetermined compressive load is applied to a sample 3 via a lever arm 6, and a constant amount of compressive strain is repeatedly applied to the sample 3. In addition, the control of the lever arm 6 is released in response to a test start signal from the device body F, and the inhibition of the lever arm 6 is released in response to a test end signal to the rubber sample calorific value measurement device body F, which is configured to measure the calorific value, etc. of the sample. It is constructed by providing a lever arm restraining device E configured to restrain the lever arm 6.

To further explain this structure, in this embodiment, the lever arm restraining device E has a threaded portion 22 at the tip of the taper pin 21, which was conventionally inserted and pulled out manually. By providing a threaded portion 25 at the tip of the shaft portion 24 of the cylinder 23 and fixing them to each other, it is possible to automate the insertion and removal work of the taper pin 21 by moving the cylinder shaft portion 24 in the X-X direction. I'm starting to be able to do it. The cylinder 23 is fixed on a cylinder support stand 26, and the cylinder support stand 26 is attached to the testing machine body frame 1 with bolts 27.
is fixed. Naturally, the shaft 24 of the cylinder 23
so that the position of and the position of the taper pin 21 match,
The position has been adjusted.

Furthermore, when inserting the taper pin 21 into the lever arm 6, the taper pin 21 is formed to be thinner than the hole 6a so that the tip of the taper pin 21 does not collide with the hole 6a of the lever arm 6.

The movement of the axis 24 of the cylinder 23 in the X--X direction is achieved by a fluid, for example compressed air. The pressure of the compressed air is adjusted by the pressure reducing valve 28, and the moving speed of the cylinder shaft 24 in the XX direction can be controlled. Position checkers 29 and 30 are attached to the outside of the cylinder 23 to detect the position of the cylinder shaft 24 in the X-X direction. When the cylinder shaft 24 is retracted (the taper pin 21 is pulled out from the lever arm 6), compressed air is supplied through the rubber hose 32 or 33 by switching the solenoid valve 31. The feed cylinder shaft 24 can be moved in the required direction along the X-X direction.

Although the counterbalances 19 and 19' are shown in FIG. 3, the electromagnetic clutch 1 is
2, worm gear 13, etc. are omitted. The level 34 is for visually observing the level of the lever arm 6, and is used to visually observe the level of the lever arm 6 before starting the test.
Insert the taper pin 21 into the lever arm 6, check the horizontality of the lever arm 6 using a spirit level 34, and adjust the zero point of the differential transformer 9 in this state.

In addition, the limit switch 35 and the vibration isolating rubber block 36 are installed to prevent the knife edge of the fulcrum 7 from being damaged or the lower anvil 5 from being damaged if the specimen 3 breaks during the test and the lever arm vibrates violently. , when the limit switch 35 operates, the electric motor stops and the vibration isolating rubber block 3
6 can suppress the vibration of the lever arm 6. Next, the relationship between the above electric motor and the taper pin 21 will be explained. If there is no abnormality in sample 3 during the test and the motor is turned off by the timer,
The power supply relay 38 shown in FIG. 4 operates and confirms via the position checker 30 whether the taper pin 21 has come out. Then, a valve switching signal is output from the position checker 30 to the solenoid valve 31.
The solenoid valve 31 is switched and the working pressure fluid flows into the expansion pressure chamber of the cylinder 23.

Then, when the cylinder 23 is extended, the taper pin 21 connected to the rod protrudes and engages the hole 6a of the lever arm 6, and the lever arm 6 can be automatically restrained before it resonates. be. Further, if an abnormality occurs due to destruction of the sample 3 during the test, the limit switch 35 is activated and the power to the motor is turned off. Then,
With the same operation as above, position checker 30
The solenoid valve 31 is switched by the signal from the cylinder 2.
By engaging the taper pin 21 with the hole 6a through the hole 6a, vibration of the lever arm 6 can be effectively prevented.

In this embodiment, the taper pin 21 is operated by an air cylinder as described above, and this means is the most effective in terms of pin movement speed, cost, and size. Of course, means for moving the taper pin 21 by moving the cylinder by moving the cylinder or moving the piston by using an eccentric may also be used.

The structure of the device F for measuring the calorific value of a rubber sample is the same as that of the conventional device described above, so a detailed explanation of the structure will be omitted here.

Next, the operation of this device G will be explained with reference to the block diagram shown in FIG.

First, the power supply 37 is turned on. 37 causes the power supply relay 38 to operate and the entire system to operate. The power to the digital timer 39 is automatically turned on, and each switch is selected according to the test conditions.

After the automatic display 55 is displayed, the operator confirms whether the sample 3 is set correctly and then presses the automatic start button 56, and the automatic start is displayed 57 and the automatic test starts. Since the taper pin 21 was inserted into the lever arm 6 at the end of the previous test, the test is always started with the taper pin 21 inserted. After the display 57 is displayed, a buzzer 57' sounds, for example, 2 seconds after a time set in advance by a timer has elapsed, the solenoid valve 31 opens and closes, the air cylinder 23 operates, and the taper pin 21 comes out. The pin is removed 58 and the position checker 30 detects 59 that the pin is removed. When the taper pin 21 is removed, the lever arm 6 becomes free and a static load 8 is applied to the sample 3. The sample 3 is compressed by the static load 8, and the lever arm 6 is tilted by the amount of compressive strain, and the horizontal balance is detected by the differential transformer 60. The motor controller 61 is activated by the balance detection signal to maintain the horizontal position of the lever arm 6. When the motor controller 61 stops operating for, for example, 5 seconds, it determines (detects 62) that the balance of the lever arm 6 is maintained, and then automatically operates the drive motor 63 for applying dynamic compressive strain to the sample 3. . Simultaneously with the operation of this drive motor, a digital timer is also started and the test time for applying 64 dynamic strains is counted. When the drive motor 63 starts operating, compressive strain is applied to the sample 3.

Generally, when the drive motor 63 starts operating, the motor speed increases to the set speed within a short time (within about 5 seconds), and the resonance point is quickly passed and a stable state is entered, so it is difficult to apply shock to the sample 3. Sample removal rarely occurs. Dynamic compressive strain is repeatedly applied to the sample 3, and if there is no abnormality, the test is terminated by timeout 68 at 64. At the same time as the test ends, a buzzer 69 sounds, and after a preset time (for example, 3 seconds) has elapsed, the solenoid valve 31 opens and closes, the air cylinder 23 operates, and the taper pin 21 is inserted into the lever arm 6. Pin insertion 70 is detected 71 by the position checker 29. Further, if the position checker does not work and pin removal detection 59 and pin insertion detection 71 are not performed, the next operation does not proceed. After detecting the pin insertion, the drive motor stops, the test 72 is completed, and a normal completion display 73 is displayed. Prepare for the next test or shut down the entire system. In addition, due to repeated compressive strain, the lever arm 6 tilts by the amount that the sample 3 is set during the test, and the motor controller 61 is actuated by the detection signal of the differential transformer 60.
The set amount is recorded on the recorder 74 as a detection signal of the differential transformer 60, and the amount of time-compressed change in the sample 3 can be known as time passes during the test. The amount of compressive strain from moment to moment is displayed on a digital panel meter 75. In addition, if the sample 3 is set too much and is deformed flat until the upper and lower anvils 4 and 5 come into contact, the upper and lower anvils 4 and 5 will repeatedly collide with each other and break. Quantity e.g.
If a compressive strain of 12 mm is detected77 and the amount of sample set is less than 12 mm, the test is continued as a normal test and the 12 mm
If this is the case, stop the test. If the test is successfully completed and stopped 72, the sample 3 is set to some extent, although it is less than 12 mm, so the lower anvil 5 must be moved downward before the start of the next test. Therefore, digital comparator 7
6, the motor controller 61 is operated so that the output from the recorder 74 becomes 0 mV (that is, the set amount is 0), and the recorder output of 0 mV is detected 80
Then, a reset 81 is performed for the next test.

Since the present invention is configured as described above, it has the following excellent effects.

(a) By automatically inserting and removing the taper pin, there is no need for workers to be near the testing machine during calorific value testing of rubber samples, making it easier to perform tests at night, especially when operating at night. It is also possible to automatically stop the test machine.

Therefore, it is possible to save labor, and
It is possible to improve the operating rate of the testing machine and improve the efficiency of calorific value testing.

(b) As a restraining means for the lever arm, there is a cylinder, a position checker that detects whether the taper pin is inserted into or removed from the hole, and a position checker that operates the expansion/contraction pressure chamber of the cylinder based on a signal from the position checker. By using a solenoid valve that controls the supply and discharge of pressurized fluid, it is possible to reliably detect the operation of inserting and removing the taper pin into the hole, and there is little play during insertion and removal, and the accuracy of the amount of movement and direction of movement is extremely high. As a result, vibration of the lever arm can be automatically prevented at the required time.

[Brief explanation of the drawing]

FIG. 1 is a perspective explanatory view showing a conventional rubber sample calorific value measuring device, and FIG. 2 is a front view explanatory view showing a rubber sample calorific value measuring device according to an embodiment of the present invention.
FIG. 3 is an explanatory side view of the same, and FIG. 4 is an operational block diagram of the same. 3...Sample, 6...Lever arm, F...Device main body, E...Lever arm restraint device, 20...Pin support base, 21...Taper pin, 23...Cylinder, 29, 30...Position Chetzker,
31... Solenoid valve, 32, 33... Hose (rubber hose).

Claims (1)

[Scope of utility model registration request] The sample is configured such that a predetermined compressive load is applied to the sample mounted at a predetermined position via a lever arm, and a constant amount of compressive strain is repeatedly applied to measure the calorific value of the sample. In an apparatus for measuring the calorific value of a rubber sample, which comprises a pin support placed in front of the fulcrum of the lever arm and near the sample, and a hole in the lever arm through which a taper pin for preventing vibration of the lever arm can be inserted and removed. A cylinder is provided on the side of the pin support for inserting and removing the taper pin into a hole formed in the pin support and the lever arm, and the cylinder includes:
A position checker is provided to detect whether the taper pin is inserted into or removed from the hole, and based on a signal from the position checker, a solenoid valve provided on a hose connecting the cylinder and the working pressure fluid source is switched and controlled. 1. A calorific value measuring device for a rubber sample, characterized in that a working pressure fluid is supplied to an extensible pressure chamber of a cylinder.