JPH0772058A - Material testing machine - Google Patents

Abstract

PURPOSE:To decrease the zero-point adjusting amount of a small-capacity load cell by linking and switching a test jig to either of a large-capacity transmitting shaft or a small-capacity transmitting shaft. CONSTITUTION:In the compression test of a large load of 100tf class, a load switching nut 6 and a locking nut 7 are screwed 20 and rotated to advance in the direction toward a compression test jig 20. A test piece is mounted on a table, and a cross head 1 is lowered. A compressing load is applied on the test piece through the jig 30. At this time, the nut 6 comes into contact with an attaching substrate 9. The compressing load is transmitted to the strain forming part of a small diameter part 4b, i.e., a large-capacity load cell 2 through the jug 30 the substrate 9 a nut 6 a lower screw part 4d of a load rod 4 large-diameter part 4c, and the cell 2 detects the load. In the case of a small load of 10tf class, both nuts are screwed back in the direction toward the head 1. The lower surface of the long hole of a projecting part 9b comes into contact with a pin 10. Therefore, the compressing load is transmitted to the strain forming part of a rod 13, i.e., a small-capacity load cell 12 through the pin 10 and a coupling 11 after the substrate 9, and the cell 12 detects the load. Therefore, the rod 13 can be made light, and the zero-point adjusting amount can be made small.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a material testing machine in which a test piece is loaded and the load is detected by a load cell, and in particular, a large-capacity load cell and a small-capacity load cell are selectively used according to the magnitude of the load load. Regarding what you do.

[0002]

2. Description of the Related Art As a material testing machine of this type, for example, one disclosed in Japanese Patent Publication No. 56-11888 is known. As shown in FIG. 3, this material testing machine rotates a pair of screw rods 52 erected on a table 51 to move a crosshead 53 up and down, whereby an upper grip 54
The load is applied to the test piece (not shown) held by the lower grip 55 and the lower grip 55. A load rod 56 connected to the lower grip 55 is inserted into a hole 51a provided in the table 51, and flanges 57 and 58 are vertically fixed to the load rod 56. The strain generating portion of the large-capacity load cell 61 is provided above the flange 57 of the load rod 56, and the strain generating portion of the small-capacity load cell 62 is provided between the flanges 57 and 58 of the load rod 56. On the other hand, the load cells 61, 6 are provided on the inner wall of the hole 51a.
A ring screw 63 for selecting any one of the two is screwed.

In the above construction, when a tensile test is performed under a large load, the ring screw 63 is rotated so that the flange 57 is provided between the ring screw 63 and the step portion 51b on the wall surface of the hole.
To pinch. When the crosshead 53 is raised in this state, the tensile load acting on the test piece is transmitted to the load rod 56 via the lower grip 55, and the load is detected by the large capacity load cell 61. At this time, the lower flange 5
Since 8 is free, the tensile load is not transmitted below the flange 57, that is, to the small capacity load cell 62. On the other hand, when performing a tensile test with a small load,
The ring screw 63 is rotated to clamp the flange 58 between the ring screw 63 and the table bottom surface 51c. At this time, a gap a is formed between the upper flange 57 and the step portion 51b. When the tensile test is performed in the same manner as described above, the tensile load acting on the test piece is also transmitted to the lower side of the flange 57,
The load is detected by the small capacity load cell 62.

[0004]

By the way, in addition to the test load, the weights of the lower grip 55 and the load rod 56 also act on the strain generating portions of the load cells 61 and 62, so that only the test load is accurately detected. In order to do so, it is necessary to adjust the zero points of the load cells 61 and 62. Especially small capacity load cell 62
Requires a higher accuracy than the large capacity load cell 61, so it is necessary to strictly adjust the zero point. However,
If the zero point adjustment amount of the small-capacity load cell 62 is large, there is an adverse effect such as a narrow load detection range. Therefore, in order to reduce the adjustment amount, the load rod 5 provided with the strain-flexing portion is provided.
It is desirable to reduce the weight of 6.

However, since the load rod 56 receives both a large load and a small load during the test, it is unavoidable to use one having high rigidity, that is, one having a heavy weight so as to withstand the large load. Therefore, the small capacity load cell 6
It is necessary to increase the zero point adjustment amount of 2 and the actual detection range becomes narrow.

An object of the present invention is to provide a material testing machine which requires a small amount of zero point adjustment for a small capacity load cell.

[0007]

The present invention is applied to a material testing machine equipped with a large-capacity load cell and a small-capacity load cell for detecting large and small capacity loads, respectively. Then, a large-capacity transmission shaft that transmits the load to the large-capacity load cell, a small-capacity transmission shaft that transmits the load to the small-capacity load cell, and a switching that connects the test jig to either the large-capacity transmission shaft or the small-capacity transmission shaft. And a mechanism to solve the above problems. Particularly, in the invention of claim 2, when the test load reaches a predetermined value when the test jig is connected to the small capacity transmission shaft,
The switching mechanism is configured to connect the test jig to the large capacity transmission shaft.

[0008]

When the test jig is connected to the large-capacity transmission shaft by the switching mechanism, the load acting on the test piece is transmitted to the large-capacity load cell via the large-capacity transmission shaft, and the load is detected by the large-capacity load cell. . When the test jig is connected to the small capacity transmission shaft, the load acting on the test piece is transmitted to the small capacity load cell via the small capacity transmission shaft, and the small capacity load cell detects the load. As described above, according to the present invention, the shafts for transmitting the load to the large capacity load cell and the small capacity load cell (the large capacity transmission shaft and the small capacity transmission shaft) are separately provided, so that the large load acts on the small capacity transmission shaft. However, if the rigidity of the large-capacity transmission shaft is increased, the rigidity of the small-capacity transmission shaft may be low. Therefore, the small-capacity transmission shaft can be reduced in weight, and the zero point adjustment amount of the small-capacity load cell can be reduced.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. 1 is a side sectional view of a material testing machine according to the present invention,
FIG. 2 is a partially enlarged view thereof. Reference numeral 1 denotes a crosshead extending in a direction orthogonal to the plane of the drawing, which is moved up and down by the rotation of a screw rod (not shown) similar to that shown in FIG. 3, for example. A main body 2a of a large-capacity load cell 2 having a maximum detection load of 100 tf is screwed onto the upper surface of the crosshead 1 with a bolt 3, and a load rod 4 penetrates the loadcell main body 2a and the crosshead 1.

The load rod 4 includes an upper screw portion 4a protruding from an upper portion of the load cell body 2a and a load cell body 2a.
A small-diameter portion 4b located inside, and a large-diameter portion 4c penetrating the guide bearing 1a provided in the crosshead 1,
The lower screw portion 4d protruding downward of the crosshead 1 is integrally formed. The small diameter portion 4a has a load cell body 2a
A beam (not shown) provided inside is connected, and a strain generating portion such as a strain gauge is provided here. Then, the load rod 4 is supported by the load cell body 2a, that is, the crosshead 1 by screwing the nut 5 into the upper screw portion 4a. Here, since a large load acts on the load rod 4 as described later, the diameter is increased in order to increase the rigidity, and the weight is inevitably heavy.

A load switching nut 6 and a lock nut 7 are screwed into the lower threaded portion 4d of the load rod 4, and these nuts 6 and 7 are in the positions shown in the left half and the right half of the figure. It is possible to advance and retract between and. 20
Is a turning rod for rotating the nuts 6 and 7, and is inserted into the insertion holes 6a and 7a provided on the outer peripheral surfaces of the nuts 6 and 7, respectively.

A mounting board 9 is mounted on the lower surface of the load switching nut 6 via a mounting ring 8, and a flange 9a of the board 9 is engaged with a flange 8a of the mounting ring 8. A projecting portion 9b provided at the center of the upper surface of the substrate 9 projects into the switching nut 6, and a joint 11 is attached to the projecting portion 9b via a pin 10 inserted into the elongated hole 9c.
The pin 10 is fitted in the joint 11 with a predetermined fit. A small-capacity load cell 12 is arranged on the upper surface of the joint 11, and the main body 12 a of the load cell 12 has a lower screw portion 4
It is screwed onto its inner peripheral surface within d. Also, the joint 11
The rod 13 erected on the upper surface of the load cell main body 12a
Through, and the nut 14 is screwed into the upper threaded portion.
A beam provided inside the load cell main body 12a is connected to the rod 13, and a strain-flexing portion is provided here. Also, the rod 13 has a smaller diameter and a smaller length than the load rod 4 described above, and its weight is also significantly reduced.

Here, when the switching nut 6 is in the position shown in the right half, the lower surface of the switching nut 6 is attached to the mounting substrate 9.
While being in contact with the upper surface of the substrate 10, the substrate 9 is in a state of being suspended by the pin 10 through the protrusion 9b. At this time, a gap G1 is formed between the upper surface of the substrate 9 and the lower surface of the joint 11.
However, a gap G2 (<G1) is formed between the lower surface of the elongated hole 9c of the substrate protrusion 9b and the pin 10. further,
A gap G5 is formed between the mounting substrate 9 and the flanges 9a, 8a of the mounting ring 8. On the other hand, when the switching nut 6 is in the position shown in the left half, the elongated hole 9 of the board protrusion 9b is
The lower surface of c contacts the pin 10, and the flange 9a of the board 9 engages with the flange 8a of the mounting ring 8. A gap G3 is formed between the upper surface of the elongated hole 9c of the protrusion 9b and the pin 10, and a gap G4 is formed between the upper surface of the substrate 9 and the lower surface of the nut 6. A space of (G1-G2) is also formed between the upper surface of the substrate 9 and the lower surface of the joint 11.

Reference numeral 30 is a ball seat type compression test jig attached to the lower surface of the attachment substrate 9. When performing a tensile test, a test piece gripping tool is attached through a universal joint instead of the compression tester jig 30.

Next, the operation of the embodiment will be described. (1) When performing a compression test under a large load: When performing a compression test under a large load of 100 tf class, first, the compression test jig 30 is attached to the substrate 9, and the load switching nut 6 and the lock are locked by the turning rod 20. Each of the nuts 7 is rotated and screwed in the M1 direction so that the state shown in the right half of FIG. 2 is obtained. When the test piece is placed on a table (not shown) and then the screw rod is rotated to lower the crosshead 1, a compressive load is applied to the test piece via the test jig 30. At this time, since the lower surface of the switching nut 6 is in contact with the upper surface of the mounting substrate 9, the compressive load is the test jig 30 →
Mounting board 9 → Switching nut 6 → Lower thread 4 of load rod 4
The load is transmitted to the small diameter portion 4b, that is, the strain generating portion of the large-capacity load cell 2 through the path of d → large-diameter portion 4c, and the load is detected by the large-capacity load cell 2.

At this time, between the upper surface of the board 9 and the lower surface of the joint 11, and between the lower surface of the elongated hole 9c of the board projection 9b and the pin 1.
Since the gaps G1 and G2 are formed between 0 and 0, the load acting on the substrate 9 is not transmitted to the joint 11, that is, the rod 13, and a large load is applied to the strain generating portion of the small capacity load cell 12. It does not work. Therefore, damage of the small capacity load cell 12 is prevented.

(2) When performing a compression test with a small load:
When performing a compression test with a small load of 10 tf class, the lock nut 7 and the switching nut 6 are screwed back in the M2 direction, and the state of the left half of FIG. 2 is obtained. At this time, since the lower surface of the elongated hole 9c of the board protrusion 9b is in contact with the pin 10, the compressive load acting on the test piece is applied to the rod 13 along the path of the test jig 30 → the mounting board 9 → the pin 10 → the joint 11. That is, the load is transmitted to the strain generating portion of the small capacity load cell 12, and the load is detected by the small capacity load cell 12. At this time, the compressive load is also transmitted from the small-capacity load cell 12 to the load rod 4, that is, the strain generating portion of the large-capacity load cell 2, but since this load is sufficiently smaller than the detectable range of the large-capacity load cell 2, there is no problem. There is no.

(3) When conducting a tensile test with a large load:
Next, a case of performing a tensile test will be described. In this case, as described above, the upper grip is attached through the universal joint instead of the compression tester jig 30. 10
When performing a tensile test with a large load of 0tf class,
As in the case of the small capacity compression, the left half state of FIG. 2 is set. In this state, when the test piece is held by the upper grip and the lower grip provided on the table side and the crosshead 1 is raised, a tensile load is applied to the test piece through the grip. At this time, since the flange 9a of the base plate 9 is engaged with the flange 8a of the mounting ring 8, the tensile load is applied to the load rod 4, that is, the large capacity load cell 2 along the route of the base plate 9 → the mounting ring 8 → the switching nut 6. Is transmitted to the strain-generating portion and the load is detected by the large-capacity load cell 2. On the other hand, at this time, since the gap G3 is formed between the upper surface of the elongated hole 9c of the protrusion 9b and the pin 10, the load acting on the substrate 9 is not transmitted to the joint 11, that is, the rod 13, and is small. Damage to the capacitive load cell 12 is prevented.

(4) When performing a tensile test with a small load:
When conducting a tensile test with a small load of 10 tf class, the state is the right half of FIG. At this time, since the substrate 9 is in a state of being suspended from the pin 10 through the protrusion 9b, the tensile load acting on the test piece is the rod 13 in the route of the substrate 9 → the pin 10 → the joint 11. That is, the load is transmitted to the strain generating portion of the small capacity load cell 12, and the load is detected by the small capacity load cell 12. At this time, similarly to the above, the tensile load is transmitted from the small capacity load cell 12 through the load rod 4 to the strain generating portion of the large capacity load cell 2 as well.
Since this load is sufficiently smaller than the detectable range of the large capacity load cell 2, there is no problem.

In this embodiment, the load is transmitted to the large-capacity load cell 2 and the small-capacity load cell 12 via separate load rods 4 and 13, and the weight of the rod 13 is minimized. The amount of zero point adjustment can be reduced, and the load detection range can be widened. Further, according to this embodiment, the following effects can be obtained. That is, in the conventional configuration shown in FIG. 3, since the switching ring nut 63 must be provided inside the table 1, the operability of the ring nut 63 is extremely poor, and both load cells 61, 62 are Since they are arranged in series, the entire apparatus including the switching mechanism such as the load cells 61 and 62 and the ring nut 63 becomes large, and when this apparatus is provided on the crosshead 53 side, the crosshead 5
The thickness of 3 must be increased. On the other hand, in the present embodiment, since the small capacity load cell 12 is housed inside the load rod 4 used for the large load test, the device can be made compact. Further, the large-capacity load cell 2 is placed on the upper surface of the crosshead 1, and the load transmission mechanism including the mounting ring 8, the mounting substrate 9, the pin 10 and the joint 11, and the switching nut 6 are not provided inside the crosshead 4. Since it is provided below it, each member can be arranged without increasing the thickness of the crosshead 4. Further, since the switching nut 6 is exposed to the outside, the switching operability is significantly improved as compared with the conventional example shown in FIG.

In the structure of the above embodiment, the load rod 4 is a large-capacity transmission shaft, the rod 13 is a small-capacity transmission shaft, the mounting ring 8, the mounting base plate 9, the pin 10, the joint 11 and the switching nut 6 are switching mechanisms. Respectively.

In the above, the case of switching between the large capacity test state and the small capacity test state by operating the switching nut 6 has been described. Next, according to the test load, the small capacity test state is switched to the large capacity test state. An example will be described in which the state is automatically switched. To achieve this, the gap G4 between the upper surface of the base plate 9 and the lower surface of the joint 11 and the gap G5 between the flanges 9a, 8a of the mounting base plate 9 and the mounting ring 8 are set to predetermined dimensions. Good.

That is, for example, when a compression test is performed, the small capacity load cell 12 and the joint 1 are responsive to the compression load.
Although the pins 1 and 10 are deformed by a small amount, the position of the mounting substrate 9 is raised by the deformation. Therefore, the size of the gap G4 may be set to be equal to the amount of rise of the mounting substrate 9 when the compression load has a predetermined value (for example, 10 tf which is the rated load of the small capacity load cell 12). According to this, when the compression load acting on the test piece reaches the above predetermined value during the small capacity compression test in the left half of the figure, the deformation of each member causes the mounting board 9 to rise. The upper surface of the substrate 9 automatically contacts the lower surface of the switching nut 6, and the test load is transmitted to the straining portion of the large-capacity load cell 2 through the route of the test jig 30 → mounting substrate 9 → switching nut 6 → load rod 4. The load is detected by the large capacity load cell 2. On the other hand, after the load is transferred to the large-capacity load cell 2 through the above-mentioned path, even if the compressive load acting on the test piece increases, the small-capacity load cell 12 still receives a load exceeding the predetermined value. In addition, the small capacity load cell 12 is not damaged. As described above, if the size of the gap G4 is set in advance in consideration of the deformation of the small capacity load cell 12 and the like,
By switching the state to the left half of the drawing, it is not necessary to operate the nuts 6 and 7 one by one when switching between large and small capacity compression tests, and work efficiency can be improved.

When a tensile test is conducted, the small-capacity load cell 12, the joint 11 and the pin 10 are deformed according to the tensile load and the position of the mounting substrate 9 is lowered. It may be set so as to be equal to the descending amount of the mounting substrate 9 when the tensile load is a predetermined value (for example, 10 tf which is the rated load of the small capacity load cell 12). According to this, when the tensile load reaches the above predetermined value during the small capacity tensile test in the right half of the drawing, the flange 9a of the base plate 9 automatically engages with the flange 8a of the mounting ring 8 when the mounting base plate 9 descends. And the test load is substrate 9 → mounting ring 8
→ The load is transmitted to the load rod 4, that is, the strain generating portion of the large capacity load cell 2 through the path of the switching nut 6, and the large capacity load cell 2
The load is detected at. In this case as well, after the load is transferred through the above-mentioned path, even if the tensile load acting on the test piece increases, the load exceeding the predetermined value does not act on the small capacity load cell 12, and the small capacity load cell 12 is not damaged. Therefore, by switching the state to the left half in the figure in advance, it is not necessary to operate the nuts 6 and 7 at the time of switching between the large and small capacity tensile tests, and the working efficiency can be improved.

The configuration of the switching mechanism is not limited to the embodiment. Also, in the above, the material testing machine of the type in which the crosshead is moved up and down by driving the screw rod to load the test piece has been explained, but the type in which the table provided under the crosshead is driven to load the test piece It may be one.

[0026]

According to the present invention, since the strain generating portions of the large capacity load cell and the small capacity load cell are provided on separate transmission shafts (large capacity transmission shaft and small capacity transmission shaft), the rigidity of the large capacity transmission shaft is increased. If the value is increased, there is no problem even if the rigidity of the small capacity transmission shaft is low. Therefore, it is possible to reduce the weight of the small-capacity transmission shaft and reduce the zero-point adjustment amount of the small-capacity load cell, thereby widening the load detection range. Particularly, according to the invention of claim 2, when the test load reaches a predetermined value while the test jig is connected to the small capacity transmission shaft, the test jig is automatically connected to the large capacity load cell. Therefore, it is not necessary to perform switching work one by one when shifting from a test with a large capacity to a test with a small capacity, or vice versa, and work efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a main part of a material testing machine according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a part of FIG.

FIG. 3 is a front view showing a conventional material testing machine.

[Explanation of symbols]

 1 Crosshead 2 Large-capacity load cell 2a Large-capacity load-cell body 4 Load rod 6 Switching nut 7 Lock nut 8 Mounting ring 9 Mounting board 10 Pin 11 Joint 12 Small-capacity load cell 12a Small-capacity load cell body 13 Rod 30 Jig for compression test

Claims (2)

[Claims] 1. A material testing machine equipped with a large capacity load cell and a small capacity load cell for detecting large and small capacity loads, respectively, and a large capacity transmission shaft for transmitting the load to the large capacity load cell and a load for the small capacity load cell. A material testing machine comprising: a small capacity transmission shaft for transmission; and a switching mechanism for connecting a test jig to either the large capacity transmission shaft or the small capacity transmission shaft. 2. The switching mechanism is configured to connect the test jig to the large capacity transmission shaft when a test load reaches a predetermined value while the test jig is connected to the small capacity transmission shaft. The material testing machine according to claim 1, wherein the material testing machine is provided.