JP2017020926A - Material testing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily execute calibration of a test force in a compression direction to a test piece.SOLUTION: In the material testing machine, as a crosshead 13 rises, a link member 33 rises with a support shaft 32 and a weight 35 arranged on the lower surface of the link member 33 becomes separated from the upper surface of a yoke 14. The weight 35 accordingly goes into a state of being hung by the link member 33 from a state of being supported by the yoke 14. A rotational moment is thus generated in the link member 33 due to the load of the weight 35, and an engagement member 21 is provided with a force in the upper direction from an engagement part 34 of a pair of link members 33.SELECTED DRAWING: Figure 2

Description

  The present invention applies a tensile load and a compressive load to a test piece by raising and lowering the cross head, and a material test for measuring the magnitude of the load applied to the test piece by a load cell disposed on the cross head. Related to the machine.

  A load cell as a force detector is disposed in a material testing machine that performs a material test for evaluating material properties by applying a tensile load or a compressive load to a test piece by raising and lowering a crosshead. . When a repeated test is performed with such a material testing machine, a measurement error occurs in the test force measured by the load cell. In order to perform material testing accurately without being affected by such measurement errors, load cell calibration, which is also called calibration, is performed to check load cell errors before performing material testing. .

  As such a calibration method, a method of using a weight (weight) for load calibration is known. When performing calibration using the weight, remove the jig such as the gripper from the testing machine, suspend the weight so that the load cell placed on the crosshead is loaded, Various operations such as an operation of attaching a pulley or the like when the direction is opposite to the gravity are generated. If the rated capacity of the material testing machine is large, the mass of the equipment used for these calibrations also tends to increase, which places a heavy burden on the user before performing the test and drops the weight during the work. It is necessary to perform work with high risk due to the above.

  For the purpose of reducing the work burden on the user and avoiding danger during the work, a weight for weight calibration is placed on the upper support installed above the crosshead, and the calibration load is applied to the load cell during calibration. There has been proposed a material testing machine with a calibration device configured to act (see Patent Document 1).

Japanese Examined Patent Publication No. 7-21445

  Since the material testing machine described in Patent Document 1 has a structure in which a downward force is applied to the load cell due to the mass of the weight, the test force in the tensile direction against the test piece can be calibrated. The test force in the compression direction cannot be calibrated for the test piece to which the direction force is applied.

  In addition, as a method of calibrating the compression direction for the test piece, a force reference device such as a loop force detector or a master load cell is installed between the platen installed on the crosshead and the base, and the test force measured by the load cell is measured. And a test force measured by a force standard can be used. However, these force standards are expensive per se, and the work of installing the force standards in the testing machine occurs on the user side. Furthermore, in order to arrange the force reference device on the testing machine so as to coincide with the load axis, skill level is required on the user side, so that the accuracy of calibration varies depending on the person installing the force reference device. Problems also arise.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a material testing machine capable of easily executing calibration of a test force in a compression direction on a test piece.

  The invention according to claim 1 applies a load to the test piece by raising and lowering the crosshead, and measures the magnitude of the load applied to the test piece by a load cell disposed on the crosshead. In the material testing machine, the engaging member connected to the load cell and the support shaft swings as the cross head rises, and one end engages with the engaging member. And a link mechanism having a link member that applies an upward force to the engaging member by the action of a weight load disposed at the other end.

  The invention according to claim 2 applies a load to the test piece by raising and lowering the crosshead, and measures the magnitude of the load applied to the test piece by a load cell disposed on the crosshead. In the material testing machine, an engaging member connected to the load cell, a yoke disposed above the cross head, a lifting member capable of moving up and down with respect to the yoke, and a support disposed on the lifting member. A link that is swingable about an axis, a weight is disposed at one end with respect to the swing center, and an engaging portion that can be engaged with the engaging member is formed at the other end. And the link member engages the engaging portion with the engaging member as the elevating member rises when the elevating member abuts on the cross head and rises together with the cross head. Do And the weight is moved from a position supported by the yoke to a position separated from the yoke as the elevating member is raised, so that the engaging member is moved via the link member. And applying an upward force.

  According to a third aspect of the present invention, in the material testing machine according to the first or second aspect, the projection connected to the engagement member and the second supported by the support member above the projection. And when the cross member is raised, the engaging member is further raised from a state where an upward force is applied, so that the protrusion comes into contact with the second weight. Then, by moving the second weight upward from the state supported by the support member, a downward force is applied to the engagement member.

  According to a fourth aspect of the present invention, in the material testing machine according to the third aspect, the downward force applied to the engaging member is greater than the upward force applied to the engaging member. .

  According to the first and second aspects of the invention, an upward force due to the gravity of the weight can be applied to the load cell via the link member and the engaging member. For this reason, calibration of the test force in the compression direction on the test piece can be easily executed.

  According to the third aspect of the present invention, the force applied to the load cell can be changed according to the height position of the crosshead.

  According to the fourth aspect of the present invention, it is possible to apply an upward force and a downward force to the load cell according to the height position of the crosshead. For this reason, it is possible to execute both the calibration of the test force in the compression direction on the test piece and the calibration of the test force in the tensile direction.

1 is a schematic front view of a material testing machine according to a first embodiment of the present invention. 1 is a schematic front view of a material testing machine according to a first embodiment of the present invention. It is a block diagram which shows the main control systems of the material testing machine which concerns on this invention. It is a front schematic diagram of the material testing machine which concerns on 2nd Embodiment of this invention. It is a front schematic diagram of the material testing machine which concerns on 2nd Embodiment of this invention. It is a front schematic diagram of the material testing machine which concerns on 2nd Embodiment of this invention.

  Embodiments of the present invention will be described with reference to the drawings. 1 and 2 are schematic front views of a material testing machine according to a first embodiment of the present invention. 1 shows a state in which a material test is executed, and FIG. 2 shows a state in which calibration of a test force in the compression direction is executed.

  The material testing machine according to the present invention includes a base 11, a pair of frames 12 erected with respect to the base 11, a yoke 14 spanned above the frames 12, and a pair of frames 12. And a crosshead 13 that moves up and down along the line. The yoke 14 is formed with a hole 25 through which an engagement member 21 described later passes. In the frame 12, a pair of screw rods that rotate synchronously by driving a motor 52 described later is disposed. Nuts provided at both ends of the crosshead 13 are screwed into these screw rods, and the crosshead 13 moves up and down by the rotation of the screw rods. The raising / lowering operation of the cross head 13 is controlled by the control unit 50 described later.

  The crosshead 13 is provided with a load cell 15. The load cell 15 is connected to a platen 17 disposed below the crosshead 13 via a fixture 28 and measures an upward force applied to the platen 17. In addition, an engaging member 21 having a recess 22 (see FIG. 1) is disposed on the load cell 15.

  In this embodiment, the platen 17 is attached to the lower portion of the crosshead 13 via a fixture 28, and the support base 16 is attached to the upper portion of the base 11 via a fixture 29. . Then, a compression test is performed by applying a compressive force to the test piece placed on the support table 16 by the support table 16 and the platen 17. In addition, when performing a tensile test with respect to a test piece, it replaces with the platen 17 and the support stand 16, and the upper holding tool 18 and the lower holding tool 19 are used so that it may mention later.

  A gate-shaped elevating member 31 is disposed on the yoke 14 so as to be movable up and down with respect to the yoke 14. The elevating member 31 is provided with a pair of support shafts 32, and each of the support shafts 32 is provided with a substantially L-shaped link member 33 that can swing around the support shaft 32. Has been. At one end of the link member 33 with respect to the swing center, an engaging portion 34 that can engage with the recess 22 in the engaging member 21 is formed. A weight 35 is disposed at the other end of the link member 33 with respect to the swing center. A convex portion 36 is formed on the lower surface of the end portion of the weight 35 that is separated from the swing center of the link member 33.

  FIG. 3 is a block diagram showing a main control system of the material testing machine according to the present invention.

  This material testing machine includes a control unit 50 that controls the entire apparatus. The control unit 50 is connected to the load cell 15 described above. The control unit 50 is connected to a displacement meter 51 that measures the displacement of the test piece when performing a material test. The control unit 50 is connected to a motor 52 for rotationally driving a pair of screw rods arranged in the frame 12. Further, the control unit 50 is also connected to an input unit 53 for performing data input and various operations. The control unit 50 changes the height position of the crosshead 13 by rotating the motor 52, and recognizes the height position of the crosshead 13 based on the number of rotations.

  In the material testing machine having the above configuration, when a normal material test is executed, the weight 35 is supported by the yoke 14 as shown in FIG. At this time, as described above, the weight 35 is formed with the convex portion 36 on the lower surface of the end portion on the side separated from the swing center of the link member 33. For this reason, the link member 33 provided with the weight 35 has a direction in which the engaging portion 34 side opposite to the weight 35 with respect to the support shaft 32 faces downward (the link 33 member on the left side in FIGS. 1 and 2). In FIG. 1 and FIG. 2 and the right link member 33 in FIG. In this state, the crosshead 13 moves up and down to execute a material test.

  In this material testing machine, when the test force is calibrated when the test force in the compression direction is applied to the test piece, the cross head 13 is raised from the state shown in FIG. As a result, the upper surface of the crosshead 13 comes into contact with the pair of left and right lower ends of the elevating member 31 having a gate shape. When the cross head 13 is further raised, the pair of left and right support shafts 32 disposed on the elevating member 31 is also raised. As the support shaft 32 rises, the weight 35 causes the link member 33 to move upward in the engagement portion 34 side opposite to the support shaft 32 (FIGS. 1 and 2). The left link 33 member in FIG. 1 starts swinging in the counterclockwise direction, and the right link member 33 in FIGS. 1 and 2 in the clockwise direction).

  If the cross head 13 continues to rise from this state, the load cell 15 rises together with the engaging member 21, and each link member 33 continues to swing further, and the engaging portion 34 at the distal end of each link member 33. However, the engagement with the recess 22 formed in the engagement member 21 starts.

  Further, if the cross head 13 continues to rise, the link members 33 continue to swing and the link members 33 rise together with the support shaft 32. Therefore, as shown in FIG. A weight 35 disposed on the yoke 14 is separated from the upper surface of the yoke 14. As a result, the weight 35 changes from the state supported by the yoke 14 to the state suspended by the link member 33. In such a state, a rotational moment due to the load of the weight 35 is generated in the link member 33, and the engagement member 21 applies an upward force from the engagement portion 34 of the pair of link members 33. Is done. As a result, an upward force is applied to the load cell 15.

  When applying a test force in the compression direction to the test piece, an upward force is applied from the platen 17 to the load cell 15. For this reason, the fact that an upward force is applied to the engagement member 21 reproduces the same state as when a test force in the compression direction is applied to the test piece.

  The magnitude of the upward force applied to the engagement member 21 by the load of the weight 35 is calculated or measured in advance. The control unit 50 shown in FIG. 3 compares the magnitude of the force and the magnitude of the force measured by the load cell 15 with the magnitude of the upward force as a reference. Thereby, calibration of the test force in the case where the test force in the compression direction is applied to the test piece is executed. This calibration result is reflected in the subsequent material test results.

  In the case where the normal material test and calibration are repeated, each link member 33 swings between the posture shown in FIG. 1 and the posture shown in FIG. At this time, the convex portion 36 of the weight 35 repeats sliding with respect to the upper surface of the yoke 14. For this reason, the contact portion of the yoke 14 with the weight 35 is preferably a member having durability and a small friction coefficient. You may make it attach to this contact part the plate which consists of a member which has durability and a small friction coefficient.

  Next, another embodiment of the present invention will be described. 4 to 6 are schematic front views of the material testing machine according to the second embodiment of the present invention. Here, FIG. 4 shows a state in which the material test is executed, FIG. 5 shows a state in which the test force in the compression direction is executed, and FIG. 6 shows a state in which the test force in the tensile direction is executed. Show. In addition, about the member similar to 1st Embodiment mentioned above, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.

  The material testing machine according to the first embodiment described above can calibrate the test force in the compression direction, whereas the material testing machine according to the second embodiment can only calibrate the test force in the compression direction. In addition, the test force in the tensile direction can be calibrated. Note that the calibration of the test force in the compression direction and the calibration of the test force in the tensile direction, which will be described later, are continuously executed under the control of the control unit 50 shown in FIG.

  In the material testing machine according to the second embodiment, a protrusion 37 having a substantially T-shaped cross section is disposed on the upper portion of the engaging member 21. A second weight 41 is disposed above the protrusion 37. A hole 26 for passage of the projection 37 is formed in the gate-type lifting member 31. The second weight 41 is supported by a support member 42 connected to the yoke 14. However, the support member 42 may be supported by being connected to a member other than the yoke 14. For example, the support member 42 may be suspended from the ceiling or the like.

  As will be described later, the weight of the second weight 41 is such that the downward force applied to the load cell 15 via the engagement member 21 and the projection 37 is a pair of link members 33 and the weight 35 due to the weight of the weight 35. It is set to be larger than the upward force applied to the load cell 15 via the engaging member 21.

  In the first embodiment described above, the platen 17 connected to the load cell 15 via the fixture 28 is attached below the crosshead 13, and the fixture 29 is provided above the base 11. A support base 16 is attached via the. On the other hand, in the second embodiment, the upper grip 18 connected to the load cell 15 via the fixture 28 is attached, and the upper part of the base 11 is attached to the lower grip via the fixture 29. The state where the gripping tool 19 is attached is shown. When the compression test is performed on the test piece, the support base 16 and the platen 17 are used as described above. In contrast, when a tensile test is performed on the test piece, an upper grip 18 and a lower grip 19 are used instead of the support base 16 and the platen 17 as shown in FIG. A gripping force is applied to the test piece by gripping both ends of the test piece with the gripping tool 18 and the lower gripping tool 19.

  In the material testing machine according to the second embodiment, when a normal material test is executed, the weight 35 is supported by the yoke 14 as shown in FIG. 4 as in the case of the material testing machine according to the first embodiment. The link member 33 is stationary in a state where the engaging portion 34 side opposite to the weight 35 with respect to the support shaft 32 swings in the downward direction. In this state, the crosshead 13 moves up and down to execute a material test.

  In this material testing machine, when the test force is calibrated, the crosshead 13 is raised from the state shown in FIG. As a result, as in the case of the first embodiment described above, the upper surface of the crosshead 13 abuts against the pair of left and right lower ends of the elevating member 31, and the crosshead 13 is further raised, whereby the elevating member 31 is disposed. The paired left and right support shafts 32 are also raised. As the support shaft 32 rises, the weight 35 causes the link member 33 to swing in the direction in which the engaging portion 34 side opposite to the weight 35 moves upward with respect to the support shaft 32. Start. If the cross head 13 continues to rise from this state, the load cell 15 rises together with the engaging member 21, and the engaging portion 34 at the tip of each link member 33 is a recess formed in the engaging member 21. Engagement with 22 is started.

  If the cross head 13 continues to rise, the link members 33 continue to swing further, and these link members 33 rise together with the support shaft 32. Therefore, as shown in FIG. A weight 35 disposed on the yoke 14 is separated from the upper surface of the yoke 14. As a result, the weight 35 changes from the state supported by the yoke 14 to the state suspended by the link member 33. In such a state, a rotational moment due to the load of the weight 35 is generated in the link member 33, and the engagement member 21 applies an upward force from the engagement portion 34 of the pair of link members 33. Is done.

  As in the case of the first embodiment, the magnitude of the upward force applied to the engagement member 21 by the load of the weight 35 is calculated or measured in advance. The control unit 50 shown in FIG. 3 compares the magnitude of the force and the magnitude of the force measured by the load cell 15 with the magnitude of the upward force as a reference. Thereby, calibration of the test force in the case where the test force in the compression direction is applied to the test piece is executed.

  Next, the crosshead 13 is further raised from the state shown in FIG. Also at this time, an upward force is applied to the load cell 15 by the action of the weight 35 via the engaging member 21. If the cross head 13 is further raised, the protrusion 37 disposed on the upper portion of the engaging member 21 comes into contact with the lower surface of the second weight 41. If the cross head 13 is further raised in this state, the lower surface of the second weight 41 is separated from the support member 42 as shown in FIG. As a result, the load by the second weight 41 is applied to the load cell 15 via the protrusion 37 and the engaging member 21.

  Here, as described above, the downward force applied to the load cell 15 via the engaging member 21 and the protrusion 37 is caused by the weight of the weight 35 via the pair of link members 33 and the engaging member 21. It is set to be larger than the upward force applied to the load cell 15. For this reason, in the state shown in FIG. 6, a downward force is applied to the engagement member 21. As a result, a downward force is applied to the load cell 15.

  When a test force in the tensile direction is applied to the test piece, a downward force is applied from the upper gripping tool 18 to the load cell 15. The fact that a downward force is applied to the engaging member 21 reproduces the same state as when a tensile test force is applied to the test piece.

  The magnitude of the downward force applied to the engaging member 21 via the protrusion 37 by the load of the second weight 41 is calculated or measured in advance. The control unit 50 shown in FIG. 3 compares the magnitude of this force with the magnitude of the force measured by the load cell 15 based on the magnitude of the downward force. Thereby, calibration of the test force in the case where the test force in the tensile direction is applied to the test piece is executed.

  In the second embodiment described above, the downward force applied to the load cell 15 via the engaging member 21 and the protrusion 37 is caused by the weight of the weight 35 and the pair of link members 33 and the engaging member 21. It is set to be larger than the upward force applied to the load cell 15 via the. For this reason, it is possible to continuously execute both calibration of the test force in the compression direction and calibration of the test force in the tensile direction. However, the downward force applied to the load cell 15 via the engaging member 21 and the protrusion 37 is applied to the load cell 15 via the pair of link members 33 and the engaging member 21 due to the weight of the weight 35. It is also possible to make it smaller than the upward force. In this case, the upward force applied to the load cell 15 can be calibrated with two different types of loads.

  Further, in the above-described embodiment, the convex portion 36 is formed on the lower surface of the end portion of the weight 35 that is separated from the swing center of the link member 33. Due to the action of the convex portion 36, the link member 33 can be stationary with the engaging portion 34 side opposite to the weight 36 with respect to the support shaft 32 always swinging in a downward direction. The weight 35 can always be slid with respect to the yoke 14 at the position of the convex portion 36. However, when the weight of the elevating member 31 is sufficiently large with respect to the weight 35, the convex portion 36 on the lower surface of the weight 36 may be omitted.

DESCRIPTION OF SYMBOLS 11 Base 12 Frame 13 Crosshead 14 Yoke 15 Load cell 16 Support stand 17 Platen 18 Upper grip 19 Lower grip 21 Engagement member 22 Recess 31 Lifting member 32 Support shaft 33 Link member 34 Engagement part 35 Weight 36 Protrusion part 37 Protrusion part 41 Second weight 42 Support member 50 Control part 52 Motor

Claims (4)

In the material testing machine that applies a load to the test piece by raising and lowering the cross head, and measures the magnitude of the load applied to the test piece by the load cell arranged in the cross head,
An engagement member coupled to the load cell;
As the cross head is raised, the support shaft rises to swing, and one end engages with the engaging member, and the weight of the weight disposed at the other end causes the above-described action. A link mechanism having a link member that applies an upward force to the engagement member;
A material testing machine characterized by comprising: In the material testing machine that applies a load to the test piece by raising and lowering the cross head, and measures the magnitude of the load applied to the test piece by the load cell arranged in the cross head,
An engagement member coupled to the load cell;
A yoke disposed above the crosshead;
An elevating member capable of elevating with respect to the yoke;
It can be swung around a support shaft disposed in the elevating member, and a weight is disposed at one end with respect to the swing center and can be engaged with the engaging member at the other end. A link member formed with an engaging portion;
With
When the elevating member comes into contact with the cross head and rises together with the cross head, the link member swings to a position where the engaging portion engages with the engaging member as the elevating member rises. In addition, as the lifting member moves up, the weight moves from a position supported by the yoke to a position separated from the yoke, so that the engaging member moves upward with respect to the engaging member. A material testing machine characterized by applying force. In the material testing machine according to claim 1 or 2,
A protrusion connected to the engaging member;
A second weight supported by a support member above the protrusion;
With
As the cross head is raised, the engaging member is further raised from a state where an upward force is applied, so that the protrusion comes into contact with the second weight, and the second weight Is a material testing machine that applies a downward force to the engagement member by moving upward from the state supported by the support member. The material testing machine according to claim 3,
A material testing machine in which a downward force applied to the engaging member is greater than an upward force applied to the engaging member.

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