JP2020094867A - Material tester - Google Patents

Abstract

To respond to a tensile compression test as well, not just dispensing with the need for replacing a joint even when types of test are changed.SOLUTION: Provided is a material tester 1 for carrying out a test to apply both of tensile and compressive forces to a test piece 40, comprising an adapter 50 for connecting a joint 4 attached to a load cell 3 for measuring the load and a test jig 6 for attaching the test piece 40. The adapter 50 includes a rod-like body 20 pin-connected to the joint 4 and a cylindrical body 30 provided coaxially with the rod-like body 20, the rod-like body 20 having a male thread formed at an edge, the cylindrical body 30 having a first female thread engaging with the male thread formed on the inner circumferential surface and constituted as a lock nut joined to an end face of the joint 4, the cylindrical body 30 having a second female thread formed thereon that is coaxial with the first female thread and engages with a male thread of the test jig 6.SELECTED DRAWING: Figure 1

Description

The present invention relates to a material testing machine for measuring strength of materials.

2. Description of the Related Art As a testing machine for measuring the strength of a material, a material testing machine is known which performs a test of applying a tensile force or a compressive force to a test piece made of the material.
A material testing machine generally includes a load mechanism that applies a load to a test piece to be tested, and a load cell that measures the load applied to the test piece. Further, the load mechanism includes a joint attached to the load cell and a test jig connected to the joint. The test piece is attached to the test jig.

When performing a tensile test to apply a tensile force to the test piece, a tensile tester is used as the test jig, and a joint of the type in which the test jig is pin-connected is used. However, in the pin connection, since there is rattling due to the gap between the pin and the pin hole, a compression test for applying a compressive force to the test piece cannot be performed. Therefore, when performing a compression test, a test jig for compression test is used, and a joint is a type that is surface-bonded to the test jig.

As described above, in the conventional material testing machine, the test jig and the joint to be used are different depending on whether the type of test is the tensile test or the compression test, so that the compression test may be performed after the tensile test or vice versa. It is necessary to replace not only the test jig but also the joint.
Moreover, in a test in which a large load is applied to the test piece, it is necessary to increase the strength of the joint so as to withstand the large load, and the mass of the joint is inevitably large.

Therefore, a material testing machine has been proposed in which replacement of the joint is not necessary even if the type of test is changed (for example, see Patent Document 1).

JP, 2008-1968880, A

However, the material testing machine of Patent Document 1 supports only a tensile test or a compression test, and does not support a tensile compression test in which both tensile force and compressive force are applied to the test piece. ..

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a material testing machine capable of not only exchanging a joint even if the type of test is changed but also supporting a tensile compression test. And

A first aspect of the present invention is a material testing machine that performs a test in which loads of both tensile force and compression force are applied to a test piece, and a joint to be attached to a load cell that measures the load, and a test jig to which the test piece is attached. , An adapter for connecting to the joint, the adapter having a rod-shaped body that is pin-connected to the joint, and a cylindrical body that is provided coaxially with the rod-shaped body, the rod-shaped body having a male threaded portion at its end. Is formed, a first female screw portion that is screwed with the male screw portion is formed on the inner peripheral surface of the tubular body, and the tubular body is a lock nut that is joined to the end surface of the joint. It is characterized in that a second female screw portion coaxial with the first female screw portion, which is screwed with the male screw portion of the test jig, is formed.

A second invention is characterized in that, in the first invention, the first female screw portion and the second female screw portion communicate with each other.

3rd invention is set to 1st or 2nd invention, Comprising: The said rod-shaped body has the diameter of the intermediate part of a longitudinal direction smaller than the said male screw part, The said cylindrical body respond|corresponds to the intermediate part of the said small diameter. It is characterized in that it has a projecting portion projecting to a portion of the inner peripheral surface, and the projecting portion prevents the tubular body from coming off.

According to the first aspect of the invention, the rod-shaped body is provided with the adapter in which the male screw portion of the rod-shaped body and the first female screw portion of the tubular body are coaxially screwed, and the rod-shaped body is pin-connected to the joint. Therefore, when performing a tensile compression test, the rod-shaped body is pin-connected to the joint to pin-connect the adapter, and in that state, the tubular body that is the lock nut is rotated and tightened to join the end surface of the joint. This makes it possible to prevent the pin connection pin from coming into pressure contact with the inner peripheral surface of the pin hole, and preventing the pin connection from rattling. Then, a male screw of a test jig for a tensile compression test is screwed onto the second female screw on the inner peripheral surface of the tubular body, and the test piece is attached to the test jig. In this state, even if both tensile force and compressive force are applied to the test piece, not only the test jig does not come off from the joint, but also the test piece does not come off from the test jig. Therefore, the tensile compression test can be performed in this state. On the other hand, when performing the tensile test, the tensile test can be performed by pin-connecting the test jig for the tensile test to the joint in the same manner as the pin connection of the adapter. That is, according to the first aspect of the present invention, it is possible not only to replace the joint even if the type of test is changed, but also to support a tensile compression test.
According to the second invention, since the first female screw portion and the second female screw portion are communicated with each other, the weight of the adapter can be reduced. Thereby, the replacement of the test jig can be facilitated.
According to the third aspect of the invention, the intermediate portion of the rod-shaped body of the adapter has a smaller diameter than the male screw portion of the end portion, and the protruding portion is provided on the inner peripheral surface portion of the cylindrical body corresponding to the intermediate portion of the small diameter. It is protruding. Therefore, even when trying to pull out the tubular body from the rod-shaped body, it is possible to prevent the protruding portion from being caught by the male screw and the tubular body from coming off. As a result, it is possible to prevent an accident due to the unexpected dropping of the cylindrical body.

It is a front view of the material testing machine which concerns on embodiment of this invention. It is a figure showing the state where the adapter is attached to the material testing machine. It is a perspective view of an adapter. It is a figure explaining the attachment method of an adapter and a test jig. It is a figure explaining the attachment method of the test jig for a tensile test.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a front view of a material testing machine 1 according to the embodiment.
As shown in FIG. 1, the material testing machine 1 of the present embodiment is a testing machine that performs a test in which loads of both tensile force and compression force are applied to the test piece 40, and a load mechanism 2 that applies a load to the test piece 40. And a load cell 3 for measuring the load applied to the test piece 40. Further, the load mechanism 2 includes a joint 4 attached to the load cell 3, an adapter 50 connected to the joint 4 by a pin 5 (pin connection), and an upper test jig screwed to the adapter 50 (test for a tensile compression test). Jig) 6). Thus, in the material testing machine 1, the adapter 50 is provided, and the joint 4 and the upper test jig 6 are connected via the adapter 50.

The load mechanism 2 will be described in more detail.
The load mechanism 2 further includes a table 7, a pair of columns 8 standing upright on the table 7, a frame 9 horizontally extending between the upper portions of the columns 8, and a non-rotatably provided inside each column 8. The illustrated ball screw and the crosshead 10 that moves up and down according to the rotation of the ball screw are provided. The load cell 3 is installed on the upper surface of the crosshead 10.

The joint 4 attached to the load cell 3 has a substantially cylindrical shape. The upper end of the joint 4 serves as a mounting portion to the load cell 3, and the lower end serves as a pin connecting portion with the adapter 50.
An upper test jig 6 is screwed to the lower end of the adapter 50, and a lower test jig 11 is provided on the table 7 below the upper test jig 6. The pair of upper and lower test jigs 6 and 11 have mounting portions 6a and 11a for gripping and mounting both end portions of the test piece 40. Even if a tensile force and a compressive force are applied to the test piece 40 by these attachment portions 6a and 11a, both ends of the test piece 40 are prevented from coming off the test jigs 6 and 11.

The adapter 50 will be described in more detail.
As shown in FIGS. 2 and 3, the adapter 50 includes a substantially cylindrical rod-shaped body 20 and a substantially cylindrical tubular body 30 provided coaxially with the rod-shaped body 20. Examples of the material for the rod-shaped body 20 and the cylindrical body 30 include metals that can withstand loads.

The rod-shaped body 20 includes a head portion 21, a small diameter portion 22 (intermediate portion), and a male screw portion 23 (lower portion) in order from the first end portion (upper portion) in the longitudinal direction. The head portion 21 has a larger diameter than the small diameter portion 22 and the male screw portion 23, and a pin hole 21a for pin connection is formed in the head portion 21. The small diameter portion 22 has a smaller diameter than the male screw portion 23.

The tubular body 30 has a through hole 31 coaxial with the central axis over the entire length, and a first female screw portion 32 that is screwed with the male screw portion 23 of the rod body 20 is formed on the upper inner peripheral surface of the through hole 31. ing.
As shown in FIG. 2, on the outer peripheral wall of the upper portion of the tubular body 30, a pair of opposing through holes 33 are provided toward the central axis of the tubular body 30, and the female screw portion 34 is formed in the through holes 33. Has been done. Bolts 35 are screwed into the female threaded portions 34, and tip portions 35 a of the bolts 35 project from the inner peripheral surface of the tubular body 30. The protruding position is a portion corresponding to the small diameter portion 22 of the rod-shaped body 20. Further, a plurality of holes 36 are formed at the same height position on the outer peripheral surface of the intermediate portion of the tubular body 30.

In the adapter 50, the outer diameter of the head portion 21 of the rod-shaped body 20 is larger than the inner diameter of the first female screw portion 32 of the tubular body 30, and the head portion 21 is located above the upper end surface 37 of the tubular body 30. doing.
A second female screw portion 38 is formed at the lower end of the tubular body 30 coaxially with the first female screw portion 32. The male screw portion 6b of the test jig 6 is screwed into the second female screw portion 38. In this embodiment, the first female threaded portion 32 and the second female threaded portion 38 are formed by forming a series of female threads in one through hole 31, but the first female threaded portion 32 and the second female threaded portion 38 are formed. Need not be in communication.
The upper end surface 37 of the tubular body 30 contacts the lower end surface 41 of the joint 4. The outer diameter of the tubular body 30 and the outer diameter of the joint 4 are substantially equal to each other, and the upper end surface 37 and the lower end surface 41 have substantially the same area.

As shown in FIG. 4, the pin connection method of the adapter 50 to the joint 4 is as follows. First, the pin hole 4a for pin connection in the joint 4 and the pin hole 21a for pin connection in the rod-shaped body 20 of the adapter 50 are coaxial. Position. Then, the pin 5 is inserted into the pin holes 4a and 21a. As a result, the adapter 50 (rod 20) is pin-connected to the joint 4. Next, after a tightening jig is fitted in the hole portion 36 (see FIGS. 2 and 3) on the outer peripheral surface of the tubular body 30, the tubular body 30 is rotated and tightened to form the upper end surface 37 of the tubular body 30. Is joined to the lower end surface 41 of the joint 4. That is, the tubular body 30 serves as a lock nut.

Then, the upper test jig 6 is screw-connected to the second female screw portion 38 (see FIGS. 2 and 3) of the adapter 50 (cylindrical body 30).
The upper test jig 6 has a male screw portion 6b for screw connection.
Here, the order of the pin connection of the adapter 50 and the screw connection of the upper test jig 6 may be reversed. That is, after the upper test jig 6 is screwed to the adapter 50, the adapter 50 may be pin-connected to the joint 4.

FIG. 2 shows a state in which the adapter 50 is pin-connected to the joint 4 and the upper test jig 6 is screw-connected to the adapter 50.
As shown in FIG. 2, a recess 4b into which the head 21 of the rod-shaped body 20 can be inserted is formed in the lower end surface 41 of the joint 4 so that the pin connection of the adapter 50 is possible. A pin hole 4a is formed on the peripheral side portion.
Further, in a state in which the tubular body 30 which is a lock nut is rotated and tightened and the upper end surface 37 of the tubular body 30 is joined to the lower end surface 41 of the joint 4, the peripheral side surface of the pin 5 for pin connection is the adapter 50. The inner peripheral surface of the pin hole 21a and the inner peripheral surface of the pin hole 4a of the joint 4 are in pressure contact with each other. As a result, the pin connection is in a loose state.

Then, both ends of the test piece 40 are attached to the upper test jig 6 and the lower test jig 11 (see FIG. 1).
In this state, not only the upper test jig 6 does not come off from the joint 4 even when a load of both tensile force and compressive force is applied to the test piece 40, but also the test piece 40 moves the upper test jig 6 and the lower part. It does not come off from the test jig 11. Therefore, the tensile compression test can be performed in this state.

In this embodiment, the tensile test can be performed by using the upper test jig 60 (see FIG. 5) for the tensile test. The upper test jig 60 includes a head 61 having the same shape and the same size as the head 21 of the rod-shaped body 20 of the adapter 50.
When performing a tensile test, first, in the reverse order of the pin connection of the adapter 50 shown in FIG. 4, the tubular body 30 which is the lock nut of the adapter 50 is rotated and loosened, the pin 5 of the pin connection is pulled out, and the adapter 50 is removed. Is removed from the joint 4 together with the upper test jig 6. Next, as shown in FIG. 5, similarly to the pin connection of the adapter 50, the pin connection pin hole 4a in the joint 4 and the pin connection pin hole 61a in the upper test jig 60 are coaxially positioned. Then, the pin 5 is inserted into the pin holes 4a and 61a. In this way, the upper test jig 60 is pin-connected to the joint 4. Further, the lower test jig (not shown) is also replaced for the tensile test. A tensile test can be performed in this state.

As described above, by using the adapter 50 for the tensile compression test, the joint 4 to be used can be the same in both the tensile compression test and the tensile test. Therefore, the tensile test may be performed after the tensile compression test. Also in the opposite case, the replacement of the joint 4 can be dispensed with.
Further, the adapter 50 pin-connected to the joint 4 and the upper test jig 60 for the tensile test can be exchanged safely by inserting and removing the pin 5.

Further, in the adapter 50, the connection portion (second female screw portion 38) with the upper test jig 6 and the lock nut (cylindrical body 30) are integrated. Therefore, since the adapter 50 can reduce the number of constituent parts, not only can the dimensional accuracy such as the parallelism of the joint surface (upper end surface 37) with the joint 4 be increased, but the size of the adapter 50 itself can be reduced and the weight thereof can be reduced. Can be converted. Further, the weight reduction makes it possible to more safely replace the adapter 50 and the upper test jig 60 for the tensile test.

Further, in this embodiment, in the adapter 50, the tip end portion 35 a of the bolt 35 that penetrates the outer peripheral wall of the tubular body 30 projects from the inner circumferential surface of the tubular body 30, and the projecting position is the small diameter of the rod body 20. It is a portion corresponding to the portion 22. Therefore, when the adapter 50 is removed from the joint 4, even if the tubular body 30, which is a lock nut, is loosened too much, the tip end portion 35a of the bolt 35 is caught by the male screw portion 23 at the lower end portion of the rod body 20, and the tubular body is It is designed such that 30 does not come off from the rod-shaped body 20. In this respect also, safety is ensured.

In the embodiment described above, in the adapter 50, the tip portion (projection portion) 35a of the bolt 35 is projected from the inner peripheral surface of the tubular body 30, but a pin or the like may be used instead of the bolt 35.
Further, even if there is no protrusion on the inner peripheral surface of the tubular body 30, not only the joint 4 does not need to be replaced, but also the tensile compression test can be achieved.

Further, in the above-described embodiment, the upper test jig 6 for the tensile compression test is screwed to the adapter 50, but the upper test jig 6 is removed and the upper test jig for the compression test is screwed to the adapter 50. Then, the compression test can be performed. Also in this case, similar to the above-described embodiment, only the test jig needs to be replaced, and the joint 4 need not be replaced.

The above-described embodiment is merely an example of the aspect of the present invention, and can be arbitrarily modified and applied without departing from the gist of the present invention.

1 Material Testing Machine 3 Load Cell 4 Joint 4a Pin Hole 5 Pin 6 Upper Test Jig 11 Lower Test Jig 20 Rod 21a Pin Hole 22 Small Diameter 23 Male Thread 30 Cylindrical (Lock Nut)
32 1st female screw part 35a Tip part (projection part)
38 2nd female thread 40 Test piece 50 Adapter 60 Upper test jig

Claims (3)

A material testing machine for performing a test in which both tensile force and compressive force are applied to a test piece,
A joint for attaching to the load cell for measuring the load, and a test jig for attaching the test piece are provided with an adapter,
The adapter has a rod-shaped body that is pin-connected to the joint, and a tubular body that is provided coaxially with the rod-shaped body,
The rod-shaped body has a male screw portion formed at the end,
The tubular body has a first female threaded portion that is screwed with the male threaded portion is formed on the inner peripheral surface, and is a lock nut that is joined to the end surface of the joint.
The material testing machine, wherein the tubular body is formed with a second female screw portion that is screwed with the male screw portion of the test jig and is coaxial with the first female screw portion. The material testing machine according to claim 1, wherein the first female screw portion and the second female screw portion are communicated with each other. The rod-shaped body, the intermediate portion in the longitudinal direction has a smaller diameter than the male screw portion,
The tubular body has a protrusion protruding to a portion of the inner peripheral surface corresponding to the small-diameter intermediate portion,
The material testing machine according to claim 1 or 2, wherein the protruding portion serves as a retainer for the tubular body.

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