JPS5824191Y2 - Tube material testing machine - Google Patents

Description

[Detailed description of the invention] This invention relates to a material testing machine that uses pipe material as a test piece.

In tensile testing of pipe materials, when gripping the end of a test piece, a method is used in which a core bar of an appropriate length is inserted into the end, and then this end is gripped from both sides by chucks of a gripping device. The gripping of the chuck prevents the end of the tube material specimen from being crushed or squeezed, which may cause breakage.

The upper end of the above-mentioned core metal is held by the core metal holder of the core metal attachment/detachment device, and the core metal holder is moved up and down by a hydraulic cylinder mechanism such as a hydraulic cylinder, so that it is inside the pipe specimen. The core bar is inserted, and when the test is completed, the core bar is pulled out from the broken pipe specimen.

Originally, no test load should be applied to this core holder and the piston that holds it, and the test load should be applied to the chuck holder, but in conventional testing machines, the core holder is directly connected to the piston. Immediately after the test starts, the chuck holder tightens due to self-locking action.
There was a drawback that the test load was applied to the core metal and the piston until the test piece was completely gripped, damaging the core metal attaching/detaching device.

This invention aims to eliminate the above-mentioned drawbacks, and is designed so that the spring absorbs the load applied to the piston via the core metal holder immediately after the start of the test. When the chuck holder is fully tightened, the chuck holder stops gripping the specimen.

Therefore, it is possible to prevent an excessive load from being applied to the core metal attaching/detaching device, which is made up of the core metal holder, the piston, and other components, and to prevent this device from being damaged.

This invention will be explained below with reference to the drawings. Reference numeral 1 shown at the bottom in FIG. 1 is a test piece of tube material, and a core bar 2 is inserted and held inside the upper end of the test piece.

The outer diameter of the core bar 2 is approximately equal to the content of the test piece 1.

As shown in FIG. 1a, the two chuck teeth 3 grip the test piece from the outside from both the left and right sides.

Each chuck tooth 3 is supported by a chuck holder 4, and each chuck holder 4 slides its outer surface up and down along the internal slope 6 of the crosshead 5, thereby gripping the test piece 1 from both sides of the outside by a wedge action. Grip and hold.

A fragment picker plate 7 is held above the chuck holder 4 by a holding fitting 8.

The core metal 2, which has slidably passed through the broken piece removal master plate 7, has its upper end connected to a core metal holder 9.

The core metal holder 9 fits into the holding metal fitting 8 so as to be able to slide up and down,
A sleeve 10 is connected to its upper end with a screw.

A lower end of a piston 11 is slidably fitted into the sleeve 10, and an annular retainer 11 is attached to the lowermost end of the piston.
A is threadedly connected.

Between the retainer 11a and the shoulder 12 of the sleeve 10,
A compressed spring 13 is interposed.

Therefore, a play is provided between the retainer 11a and the sleeve 10 in the insertion/removal direction.

The sleeve 10 is slidably fitted within a bushing 14, which is connected at its upper end to a cylinder 15 as shown.

The cylinder 15 has its lower end fixed to the upper surface of the crosshead 5 and has upper and lower ports 16,17.

The piston 11 in the cylinder can be moved in either the up or down direction by communicating either one of these ports (16, 17) with a hydraulic source and discharging oil from the other port.

Next, the operation will be explained.

The lower end of the test piece 1 is held by a lower crosshead (not shown).

By lowering this lower crosshead downward away from the upper crosshead 5, a tensile load is applied to the test piece 1, and a tensile test is performed.

In order to grip the upper end of the test piece 1 with the chuck teeth 3, first operate a handle (not shown) to position each chuck holder 4 at a position slightly above the position shown in the figure.

Since the chuck holder 4 slides along the slope 6 of the crosshead, when it moves upward, the gap between the chuck teeth is widened.

Position the upper end of the test piece 1 between the teeth of the chuck that is wide open in this way, and then move the chuck holder 4 by operating the handle.
is lowered along the slope 6.

This lowering narrows the gap between the two chuck teeth 3, and the upper end of the test piece 1 is gripped by both the chuck teeth from both the left and right sides as shown in FIG. 1a.

However, up to this point, the core metal 2 remains held upward and has not yet been inserted into the test piece 1.

Next, when hydraulic pressure is supplied from the port 16 above the cylinder 15 and the piston 11 is lowered, the lower core metal holder 9
At the same time, the core metal 2 is lowered and inserted into the test piece 1 as shown in FIG. 1, and preparation for the test is completed.

Next, when a tensile test load is applied to the test piece, both chuck teeth are also pulled downward by the frictional force, so that the chatuku holder 4 slides on the slope 6, and the gripping force on the test piece 1 is further strengthened by the wedge action. , to be able to sufficiently withstand the load of the test.

As mentioned above, by the time the wedge action is performed and the gripping force of the chuck teeth 3 becomes effective, frictional force is already generated between the test piece 1 and the core metal 2. The initial load applied to the core metal holder 9 and sleeve 10 are transmitted through the core metal 2 to the upper metal core holder 9 and sleeve 10.

However, although this load allows the sleeve 10 to compress the spring 13 and move downward, even if the piston 11 is at its lowest position at this time, the piston 11
The receiver is stopped and stopped at the lowermost end 15a of the cylinder 15 without being subjected to an unreasonable load.

That is, at the beginning of the tensile test, the core metal 2 is inserted into the test piece 1 with the upper end surface of the sleeve 10 in contact with the stepped portion 11b of the piston 11 by the spring 13 as shown in the figure. However, the spring is compressed as described above within a very short period of time immediately after the test load is applied to the test specimen 1, and the unreasonable load is prevented from being applied to the piston. It is possible.

Note that after the test is completed, the lower port 1 of the cylinder 15 is
When the piston 11 is raised by supplying hydraulic pressure from 7, the piston 11 is raised.

At that time, the retainer 11a at the lowest end of the piston, the spring 13,
The core metal 2 also rises by 1.0 cm along with the piston 11 via the sleeve 10 and the core metal holder 9.

At this time, the fracture test piece 1 also rises together with the core bar 2, and the upper end hits the fracture membrane plate 7 and stops.The core bar 2 is also lifted, so the core bar 2 is peeled off from the test piece 1. .

While the core metal is released in this way, the spring 13 is compressed again, but the annular step 10a on the inner circumference of the sleeve 10
contacts the retainer 11a to prevent the spring 13 from being compressed any further.

Since the material testing machine of this invention operates as explained above, it prevents damage to the core metal attachment/detachment device due to abnormal force being applied to the core metal attachment/detachment device in the early stage of the tensile test, and enables accurate material testing. It is possible to do this.

In the embodiment shown in FIG. 2, the cylinder 15' is attached to the crosshead 5' so that it can slide up and down, that is, with a certain play.

That is, the ring 2 fixed to the outer periphery of the lower end of the cylinder 15'
0 is slidably engaged with a plurality of guide pins 21 installed on the crosshead 5', and a spring 13' is interposed between the ring 20 and the crosshead 5'.

Note that the core metal holder 9' and the piston 11' are integrally connected as shown.

When a load is applied to the piston 11' through the core metal 2 at the beginning of the test, the ring 20 at the lower end of the cylinder 15'
Cylinder 15' moves downward while compressing cylinder 3'.

Note that the bushing 14' is integrally connected to the cylinder and is slidably fitted into the crosshead 5'.

Components in the embodiment in FIG. 2 that correspond to those in the embodiment in FIG. 1 are shown with the same reference numerals as in FIG.

[Brief explanation of the drawing]

Figure 1 is a longitudinal cross-sectional view of a pipe material testing machine based on this invention.
FIG. 1a is a cross-sectional view of the chuck tooth taken along the line 1a-1a in FIG. 1, and FIG. 2 is a longitudinal cross-sectional view of another embodiment. 1... Test piece, 2... Core bar, 3...
...Chuck teeth, 4...Chuck holder,
9... Core metal holder, 10... Sleeve, 11... Piston, 11a... Retainer, 13... Spring, 14... ...butsu, 15... cylinder, 16.17...
··port.

Claims (1)

[Scope of utility model registration request] A pair of chuck teeth grip the pipe material test piece from the outside by a wedge action, and in a material testing machine where a core metal is inserted into the gripping part of the pipe material, the cross section of the testing machine is used to insert and remove the core metal. The head is equipped with a hydraulic cylinder mechanism, and an elastic body is interposed between the core metal and the hydraulic cylinder mechanism, or between the hydraulic cylinder and the cross head, and each has a fixed free movement distance in the direction of insertion and removal of the core metal. A pipe material testing machine characterized by being equipped with.