JPH02284018A - Extensometer - Google Patents

Abstract

PURPOSE:To accurately measure the elongation of a sample by bringing a circular motion body which has a shaft into contact with a gage mark and grasping the displacement of the gage point as arcuate motion. CONSTITUTION:The circular motion body 3 which has the shaft 5 is brought into contact with the gage point 2, whose displacement is grasped as the arcuate motion; and a detector 7 detects the displacement of the gage point 2 by an angle measuring instrument provided on the shaft 5 of the circular motion body 5. Then the detector 7 calculates the addition value of the obtained tilt angle of the circular motion body 3 and the movement quantity of the base 8 of a detecting mechanism at both the upper and lower gage points and the quantity of elongation between the gage points 2 is represented as the difference between the both. Further, when the detector 7 exceeds a set value, the base 8 of the detecting mechanism follows while moving by a constant quantity. In this case, an error due to the delay in the movement of the base 8 is corrected by the detector 7, so the error is eliminated and the elongation of the sample 1 can, therefore, be measured stably and accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an extensometer. Specifically, by detecting the displacement of the gauge point of the sample using a circularly moving body,
This invention relates to an extensometer that can stably and accurately measure the elongation of a sample.

[Prior art and problem to be solved by the invention 1 A lever-type gripping arm is used as an extensometer having a fi41t that detects the displacement of the gauge point of the sample and a tracking mechanism that tracks the displacement of this gauge point, and the gripping arm is An extensometer is known in which a gage of a sample is gripped at one end of the extensometer, and a displacement detector is installed at the other end via a fulcrum.

In order to obtain a certain degree of sensitivity with this type of extensometer, it is necessary to use one with a long gripping arm, but when doing so, ■ it tends to become unstable.

■ The deflection of the gripping arm cannot be ignored.

■ The shock when the sample breaks also increases, and the effect on the detector increases.

■ Adding a protection mechanism will complicate the structure.

■ The size of the equipment will increase.

However, there is a need for a device that can perform stable and highly accurate measurements, rather than being completely satisfactory.

rP! Means for Solving Problem J 1 As a result of extensive research in order to improve the above-mentioned drawbacks, the present inventor has developed an 81 mechanism for detecting the displacement of the gauge point of a sample using a shaft instead of a lever type. The present invention was completed based on the knowledge that the above-mentioned drawbacks can be significantly improved by detecting the displacement of a gauge point using a circularly moving body having a circular motion body.

That is, an object of the present invention is to provide an extensometer that can stably and accurately measure the elongation of a sample. In an extensometer that has a detection mechanism that emits a signal according to the amount and a tracking mechanism that uses the signal to track the displacement of the gauge, the detection mechanism includes a circularly moving body having a shaft that is brought into contact with the gauge, and the displacement of the gauge is detected. Detection ffi?, which captures the displacement as a circular arc movement and detects the displacement of the gauge point with an angle measuring device installed on the axis of the circularly moving body. This is an extensometer characterized by using m.

The extensometer of the present invention can be used to measure the displacement of gauge points on industrial materials such as plastics, rubber, metals, and wood, and the extensometer is usually used in conjunction with a tensile testing machine or similar device. Ru.

The extensometer of the present invention is characterized by a detection mechanism for detecting the displacement of a gauge point, and a conventionally known tracking mechanism can be used as the tracking mechanism. As a specific example of how many tracking h1,
The base on which the detection mechanism is loaded is placed outside using a belt or feed screw, and the amount of elevation is detected by a detector such as a magnescale or encoder, and compared with the amount of displacement of the gauge point detected by the detection mechanism.1 For this reason, examples include methods that perform tracking.

Hereinafter, the detection mechanism of the present invention will be explained with reference to the drawings.

FIG. 1 is a sketch showing an example of the detection mechanism of the extensometer of the present invention. FIG. 2 is a partially cutaway side view of the circular motion body of the detection mechanism.

In the figure, 1 is the sample, 2 is the reference point, 3 is the circularly moving body, and 4 is the sample.
is the connection between the circular motion body and the shaft, 5 is the pongee, 6.6゛ is the bearing,
7 is the detector, 8 is the base of the detection 811 structure, 9 is the measuring head, 1
0 is a measuring tip shaft, 11 is a spring, and 12 is a support provided opposite the measuring tip 9.

Sample 1 is attached at its top and bottom to a tensile testing machine (not shown), and tension is applied. ↑T, α2 is a fine mark provided on the surface of the sample 1. Although only one is shown in Figure 3, it is usually provided above and below the sample 1, and is attached to the measuring head 9 of the circular moving body 3, respectively. Touch the tips. It is preferable to provide a support on the back side of the gauge point 2 so that the contact state of the probe 9 does not change. A specific example of the support is, for example, a support 12 in FIG. 2 which has the same shape as the measuring element 9.

As the circular motion body 3, a cylindrical body having an arrow-shaped measuring element 9 is shown in the figure, but the shape is limited to this as long as it has a member that contacts the gauge point 2 and circular motion is possible. It's not a thing. FIG. 2 shows an example of a circularly moving body. Inside the circularly moving body 3, a gauge head shaft 10 connected to a gauge head 9 is housed, and the gauge head 9 is connected to the gauge point 2 of the sample 1. The probe shaft 10 is pushed forward by a spring 11 to ensure sufficient contact. It is preferable that the tip of the measuring stylus 9 be in α contact with the gauge point 2 in order to avoid errors due to slippage.

The size of the circular moving body 3 is preferably selected from a range of 20"IL40+us" in terms of the length from the center line of the shaft 5 to the tip of the probe 9. If this length is too long, the device will become thick (and the angle for detecting the displacement of gauge point 2 will be small.On the other hand, if this length is too short, the angle for detecting the displacement of gauge point 2 will be large, but There is a risk that slippage may occur between the gauge point 2 and the measuring point 9.Also, the angle of rotation of the circularly moving body 3 depends on how the base 8 is tracked, but is usually within 2 degrees, preferably within 1 degree. It is best to set it so that it is within .

The connection 4 between the circular motion body and the shaft is a member that holds the circular motion body 3 and transmits the rotation of the circular motion body 3 to the pongee 5, and may be formed integrally with the circular motion body 3. The shaft 5 rotates according to the displacement of the gauge point 2, but it is necessary that it rotates smoothly and has no play. In addition, it has a certain length and the bearing 6.6'
It is better to leave a wide space between. Preferably, the pongee 5 is housed in a circumscribing pipe and the entire vibe is used as a bearing. In this case, extremely accurate measurements are possible. As the detector 7, various measuring instruments can be used as long as they are capable of measuring minute angles, but for example, it is preferable to use an encoder 1 displacement sensor or the like.

The amount of elongation between the gauge points is calculated by adding the inclination angle of the circularly moving body 3 obtained by the detector 7 and the amount of movement of the base 8 of the detection mechanism at both the upper gauge point and the lower gauge point. and is expressed as the difference between the two.

When the value of the detector 7 exceeds a set value, the base 8 of the detection mechanism follows it while moving by a certain amount. In this case, the error caused by the delay in the movement of the base 8 of the detector 1 is corrected by the detector 7, so it does not become an error.

1. Effects of the Invention] The extensometer of the present invention has a simple structure, has few failures, and can stably and accurately measure the elongation of a sample. Moreover,
The shorter the length of the circular motion, the better the viscosity tends to be, and the device can be made smaller. Furthermore, even if the sample breaks, the shock can be avoided by the rotation of the circularly moving body, so there is no need to worry about damage to the apparatus due to the sample breaking.

[Brief explanation of drawings]

FIG. 1 is a sketch showing an example of the detection mechanism of the extensometer of the present invention. FIG. 2 is a partially cutaway side view of the circular motion body of the detection mechanism.

Claims (1)

[Claims] (1) An extensometer that has a detection mechanism that detects the displacement of a gauge on a sample and issues a signal according to the amount of displacement, and a tracking mechanism that tracks the displacement of the gauge using the signal, which has a shaft as the detection mechanism. It is characterized by using a detection mechanism that brings a circularly moving body into contact with a gauge point, detects the displacement of the gauge point as a circular arc motion, and detects the displacement of the gauge point with an angle measuring device provided on the axis of the circularly moving body. Extensometer.