Material Testing Machine

Abstract

To provide a material testing machine in which the positional relation between a pair of grippers and a pair of arms can be appropriately changed by a simple structure.SOLUTION: A material testing machine (1) comprises: a load mechanism (35) for loading a test force on a test piece (T) both ends of which are held by a pair of grippers (38, 39); and an elongation measuring device (70) for fixing a pair of arms (80, 90) to a pair of marked lines (M1, M2) provided on the test piece (T) and measuring an elongation between the pair of marked lines (M1, M2). In the material testing machine (1), the elongation measuring device (70) includes a positioning mechanism (100) for pushing and moving the pair of arms (80, 90) in conjunction with the movement of the load mechanism (35) and positioning the pair of arms (80, 90) between the pair of grippers (38, 39). The positioning mechanism (100) includes an actuator (102) for adjusting push and move amounts (U1, U2) of the pair of arms (80, 90) in accordance with the length of the test piece (T).SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a materials testing machine. [Background technology]

[0002] BACKGROUND ART Conventionally, a material testing machine has been proposed that includes an elongation measuring device that measures the elongation between a pair of benchmark lines provided on a test piece by fixing a pair of arms to the pair of benchmark lines (Patent Document 1). When a tensile test is performed, this elongation measuring device drives a pair of arms with a pair of pulse motors to position the pair of arms at any position between a pair of grippers. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-333382 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the conventional extension measuring device described above has a problem in that the configuration of the drive system becomes complicated because the pair of arms is driven by a pair of pulse motors. The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a materials testing machine that can appropriately change the positional relationship between a pair of grippers and a pair of arms with a simple configuration. [Means for solving the problem]

[0005] A first aspect of the present invention is an elongation measuring device that includes a loading mechanism that applies a test force to a test piece whose both ends are gripped by a pair of gripping tools, a pair of arms that are fixed to a pair of benchmark lines provided on the test piece, and measures the elongation between the pair of benchmark lines; a test strip storage device that stores the test strip; a transport device that removes the test strip from the test strip storage device and transfers the test strip to the loading mechanism; and a control device that acquires length information of the test strip and drives an actuator based on the length information. Equipped with TaIn the material testing machine, the elongation measuring device includes a positioning mechanism that pushes the pair of arms in conjunction with the movement of the loading mechanism and positions the pair of arms between the pair of grippers, and the positioning mechanism adjusts the amount of pushing of the pair of arms depending on the length of the test piece. The aforementioned Equipped with an actuator and the control device drives the actuator so that the test piece is pushed by a predetermined amount according to the length of the test piece when the test piece is transferred from the transport device to the loading mechanism. . [Effects of the Invention]

[0006] According to the first aspect of the present invention, the positioning mechanism is equipped with an actuator that adjusts the amount of pushing of the pair of arms depending on the length of the test piece, so that the positional relationship between the pair of gripping tools and the pair of arms can be changed with a simple configuration. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram of a material testing machine according to an embodiment. [Figure 2] FIG. 2 is a side view showing the main parts of the elongation measuring device and the testing device. [Figure 3] FIG. 2 is a perspective view showing the main parts of an elongation measuring device and a testing device. [Figure 4] FIG. 1 is an explanatory diagram for testing a test piece. [Figure 5] FIG. 5 is an explanatory diagram for testing a test piece that is shorter than the test piece described in FIGS. 2 and 4. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0009] [1. Embodiment] FIG. 1 is a diagram of a material testing machine 1 according to an embodiment. A material testing machine 1 as an example of the "material testing machine" of this embodiment applies a test load as a test force to a test piece T, thereby measuring the tensile force and elongation of the test piece T.

[0010] The material testing machine 1 includes a test piece supplying device 10 , a testing device 30 , a test piece collecting device 50 , an elongation measuring device 70 , and a control device 200 .

[0011] The test piece supply device 10 includes a test piece storage device 12 that stores test pieces T in a contained state on a pallet 11, a measuring device 14 that measures the dimensions of the test pieces T, a transport table 13 to which the pallets 11 are transported from the test piece storage device 12, and a transport device 20 that transports the test pieces T from the pallets 11 supplied to the transport table 13 to the testing device 30.

[0012] The test piece storage device 12 stores a plurality of pallets 11, each containing a test piece T, stacked one on top of the other.

[0013] The test device 30 applies a test load to the test piece T supplied from the test piece supply device 10 to test the test piece T. In this embodiment, a front-to-back direction FD (see FIGS. 2 and 3), a width direction SD, and a top-to-bottom direction TD are used with respect to the testing apparatus 30 shown in Fig. 1. The width direction SD is also called the left-to-right direction.

[0014] The testing apparatus 30 has a base 31. A table 32 is provided on top of the base 31. A support column 33 extending vertically upward is provided on the table 32. A pair of support columns 33 are provided in the width direction SD of the testing apparatus 30. A cross yoke 34 extending between the pair of support columns 33 is suspended on top of the support columns 33. A threaded rod (not shown) is provided inside the support column 33. The threaded rod is composed of a ball screw. Both ends of a crosshead 35 are connected to the threaded rod via nuts (not shown). The crosshead 35 moves up and down relative to the table 32 by rotation of the threaded rod. The threaded rod is rotated by a motor (not shown).

[0015] A load cell 36 is installed on the crosshead 35. A joint 37 is attached to the load cell 36. The joint 37 extends downward. An upper gripping tool 38 is connected to the lower end of the joint 37. A cylinder device (not shown) is arranged on the upper gripping tool 38. By operating the cylinder device (not shown), the upper gripping tool 38 opens and closes in the width direction SD. The upper gripping tool 38 grips the upper end of the test piece T in an upright state. The test piece T is placed on the gripping center L of the upper gripping tool 38.

[0016] A lower gripping tool 39 is disposed below the upper gripping tool 38. The lower gripping tool 39 is fixed to the upper surface of the table 32 via a joint 40. The lower gripping tool 39 is configured similarly to the upper gripping tool 38, except that it is configured symmetrically in the upright position relative to the upper gripping tool 38. The lower gripping tool 39 grips the lower end of the test piece T in an upright position. The test piece T is disposed on the gripping center L of the lower gripping tool 39.

[0017] With the test piece T gripped by the upper gripping tool 38 and the lower gripping tool 39, the upper gripping tool 38 moves up and down together with the crosshead 35. As a result, a test force is applied to the test piece T gripped between the upper gripping tool 38 and the lower gripping tool 39. At this time, the load cell 36 measures the test force applied by the upper gripping tool 38 via the joint 37. A measurement signal from the load cell 36 is input to the control device 200.

[0018] A test strip recovery device 50 is disposed to the right of the upper gripping tool 38 and the lower gripping tool 39. The test strip recovery device 50 recovers the test strip T from the testing device 30. The test piece collection device 50 includes an upper collection device 51 provided in correspondence with the upper gripping tool 38, and a lower collection device 61 provided in correspondence with the lower gripping tool 39. The upper collection device 51 is fixed to the crosshead 35 and can be raised and lowered together with the crosshead 35. The lower collection device 61 is fixed to the upper surface of the table 32.

[0019] FIG. 2 is a side view showing the elongation measuring device 70 and the main parts of the testing device 30. As shown in FIG. The material testing machine 1 is equipped with an elongation measuring device 70 that measures the elongation of the test piece T when a test force is applied by the testing device 30. The elongation measuring device 70 of this embodiment is a contact-type extensometer that measures the elongation by contacting arms 80 and 90 with the test piece T. The elongation measuring device 70 is disposed behind the crosshead 35 (the rear side of the paper in FIG. 1). The elongation measuring device 70 is fixed, for example, to the upper surface of the table 32 of the testing apparatus 30. The elongation measuring device 70 includes an exterior frame 71 extending in the up-down direction TD. A guide rod 72 is supported in front of the exterior frame 71. The guide rod 72 extends along the support columns 33 (see FIG. 1) of the testing apparatus 30. An upper arm 80 and a lower arm 90 are slidably supported on the guide rod 72. The upper arm 80 and the lower arm 90 are disposed between the upper grip 38 and the lower grip 39 of the testing apparatus 30.

[0020] A pair of pulleys 73A, 73B are rotatably supported inside the upper end of the exterior frame 71, corresponding to the arms 80, 90, respectively. Belts 75A, 75B, which serve as an example of a connecting member, are wound around each of the pulleys 73A, 73B from above. One end of the belts 75A, 75B is connected to the arms 80, 90. Balance weights 76A, 76B are suspended from the other ends of the belts 75A, 75B. The balance weights 76A, 76B are set to weights corresponding to the weights of the corresponding arms 80, 90. The balance weights 76A, 76B apply a force to the arms 80, 90 via the belts 75A, 75B to counteract the weights of the arms 80, 90. As a result, when an external force acts in the vertical direction TD, the arms 80, 90 are easily moved in the vertical direction TD along the guide rod 72 in response to the external force.

[0021] Rotary encoders 74A and 74B are connected to the pulleys 73A and 73B, respectively. The rotary encoders 74A and 74B detect the amount of rotation of the pulleys 73A and 73B. When the arms 80 and 90 move in the up-down direction TD, the pulleys 73A and 73B rotate via the belts 75A and 75B. Therefore, the amount of rotation of the pulleys 73A and 73B is measured by the rotary encoders 74A and 74B and input to the control device 200, which can measure the amount of movement of the arms 80 and 90 based on the amount of rotation of the pulleys 73A and 73B.

[0022] FIG. 3 is a perspective view showing the main parts of the elongation measuring device 70 and the testing device 30. As shown in FIG. The upper arm 80 has a sliding portion 81 slidably supported on the guide rod 72. The sliding portion 81 is supported on the guide rod 72 via, for example, a linear bushing. A pair of clamping members 82 extending forward is supported on the sliding portion 81. The base end of the clamping members 82 is supported rotatably about a hinge shaft (not shown) extending vertically, and the tip end is configured to be openable and closable. A tension spring (elastic member) 83 is attached to the lower part of the pair of clamping members 82 in a straddling state. The tension spring 83 biases the clamping members 82 in the closing direction. Pressed rollers 84 are provided on the upper part of the pair of clamping members 82. A cylinder mechanism 85 is arranged between the pressed rollers 84.

[0023] The cylinder mechanism 85 is composed of an air cylinder. The cylinder mechanism 85 has a conical rod tip 85A. When the rod tip 85A enters between the pressed rollers 84, it pushes the clamping members 82 apart against the elastic force of the tension spring 83, causing them to open. When the rod tip 85A retreats from between the pressed rollers 84, the elastic force of the tension spring 83 causes the clamping members 82 to close. When the cylinder mechanism 85 closes the clamping members 82, the upper arm 80 clamps the test piece T and fixes it to the test piece T. In this embodiment, the upper arm 80 is formed with a plate-shaped pressure receiving portion 86 (see FIG. 2).

[0024] The lower arm 90 is configured to be substantially symmetrical in the vertical direction with the upper arm 80. In detail, the lower arm 90 has members 91 to 95 that correspond to the members 81 to 85 of the upper arm 80. The lower arm 90 is also formed with a detachable portion 92A having a downwardly recessed attachment / detachment hole. A collar 96 extending in the up-down direction TD is detachably supported by the detachable portion 92A. The collar 96 is a rod configured to have a length corresponding to the gauge length λ1, λ2 of the test piece T (see FIGS. 4 and 5). The upper arm 80 abuts against the top surface of the collar 96, thereby maintaining the gauge length λ1, λ2 between the upper arm 80 and the lower arm 90.

[0025] In this embodiment, a plurality of collars 96 of different lengths corresponding to the lengths of the test piece T are prepared, and the collars 96 are selectively used. This allows the spacing between the upper arm 80 and the lower arm 90 to be set to the predetermined gauge length distances λ1 and λ2.

[0026] A stopper 77 is fixed to the lower part of the guide rod 72. The stopper 77 has a clamp structure. The stopper 77 clamps the guide rod 72, thereby fixing the guide rod 72 at a predetermined height. The predetermined height corresponds to the height of the lower gripping tool 39. The upper surface of the stopper 77 comes into contact with the lower arm 90, restricting the downward movement of the lower arm 90. The stopper 77 sets the lower limit position of the lower arm 90.

[0027] A plate-like adjuster 78 having a predetermined thickness is detachably supported on the upper surface of the stopper 77. The adjuster 78 is formed, for example, in a substantially C-shaped plate shape that fits onto the guide rod 72. The adjuster 78 fits onto the guide rod 72 and is supported on the upper surface of the stopper 77. As a result, the upper surface of the stopper 77 is raised by the thickness of the adjuster 78. In other words, the adjuster 78 is a member that variably adjusts the lower limit position of the lower arm 90 that is set by the stopper 77.

[0028] In this embodiment, a plurality of adjusters 78 of different heights are prepared corresponding to the distances D1, D2 (see FIGS. 4 and 5) between the lower marking line M2 of the test piece T and the lower gripping tool 39, and the adjusters 78 are selectively used. Note that "selectively arranging the adjuster 78 relative to the stopper 77" is also used to mean the case where the adjuster 78 is not arranged relative to the stopper 77. This makes it easier to adjust the lower limit position of the lower arm 90 compared to the case where the stopper 77 is unclamped and clamped to adjust the position of the stopper 77 relative to the lower gripping tool 39. The stopper 77 and the adjuster 78 constitute a stopper mechanism 79 of the lower arm 90 of this embodiment.

[0029] As shown in FIGS. 2 and 3, a positioning mechanism 100 is provided on the crosshead (load mechanism) 35 located above the upper arm 80. The positioning mechanism 100 has a connecting frame 101 connected to the crosshead 35. The connecting frame 101 is in the form of a bent plate extending downward from the crosshead 35. A triangular plate-shaped rib 101A is supported on the connecting frame 101. The rib 101A ensures the rigidity of the bent plate-shaped connecting frame 101. An actuator 102 is supported on the lower end of the connecting frame 101.

[0030] In this embodiment, the actuator 102 is configured by an air cylinder. The actuator 102 includes a cylinder portion 102A and a rod portion 102B that is supported so as to be extendable and contractible in the up-down direction TD relative to the cylinder portion 102A.

[0031] A pressing mechanism (shock absorbing member) 104 is connected to the rod portion 102B via a connecting plate 103 in the form of a bent plate. The pressing mechanism 104 descends together with the crosshead 35 and presses the pressure receiving portion 86 of the upper arm 80 downward when it comes into contact with the pressure receiving portion 86. In this embodiment, the pressing mechanism 104 is configured by an air cylinder. The pressing mechanism 104 includes a cylinder portion 104A fixed to the connecting plate 103, a rod portion 104B supported so as to be extendable and contractible in the up-down direction TD relative to the cylinder portion 104A, and a pressing element 104C supported at the lower end of the rod portion 104B. The lower end of the pressing element 104C is positioned below the upper gripping tool 38.

[0032] The pressing mechanism 104 holds the rod portion 104B with a force smaller than the force with which the actuator 102 holds the rod portion 102B. The pressing mechanism 104 functions as a buffer mechanism.

[0033] As shown in FIG. 1 , the materials testing machine 1 is provided with a control device 200 that controls each component of the materials testing machine 1. The control device 200 is connected to the materials testing machine 1 so as to be able to send and receive signals to and from the materials testing machine 1. The signals received by the control device 200 include measurement signals output by the load cell 36, measurement signals output by the rotary encoders 74A and 74B, and other appropriate signals required for control and testing. The signals transmitted by the control device 200 include control signals for the test piece supply device 10, control signals for the cylinder devices (not shown) of the grippers 38 and 39, control signals for the motors of the threaded rods (not shown), control signals for the recovery devices 51 and 61, control signals for the cylinder device (not shown) of the actuator 102, and other appropriate signals required for control and testing.

[0034] The control device 200 includes a computer, which includes a processor such as a CPU (Central Processing Unit) or MPU (Micro-Processing Unit), a memory device such as a ROM (Read Only Memory) or RAM (Random Access Memory), a storage device such as an HDD (Hard Disk Drive) or SSD (Solid State Drive), and an interface circuit for connecting the control device 200 and various peripheral devices. The processor executes a control program stored in the memory device or storage device, thereby realizing various functions of the materials testing machine 1.

[0035] The control device 200 stores length information of each test piece T. Here, if test pieces T of the same standard are stored on each pallet 11 and the standard of the test piece T is changed for each pallet 11, the length of the test piece T may be stored for each pallet 11. Before starting the test, the operator can input the length of each test piece T into the control device 200, causing the control device 200 to store the length of each test piece T.

[0036] The control device 200 acquires these descent amounts and pushing amounts based on, for example, reference information corresponding to the length of the test piece. Then, when the test piece T is transferred from the transport device 20 to the upper gripping tool 38, the control device 200 lowers the crosshead 35 by an amount corresponding to the length of the test piece T. Furthermore, when the test piece T is transferred from the transport device 20 to the upper gripping tool 38, the control device 200 controls the actuator 102 to perform pushing amounts U1 and U2 (see FIGS. 4 and 5) corresponding to the length of the test piece T. Instead of the length of the test piece T, the descent amount and pushing amount of the test piece T may be stored. Before starting the test, the elongation measuring device 70 selectively positions the adjuster 78 in the stopper mechanism 79. Also, the lower arm 90 is selectively fitted with a collar 96.

[0037] Fig. 4 is an explanatory diagram for testing a test piece T. Fig. 5 is an explanatory diagram for testing a test piece T that is shorter than the test piece T described in Figs. 2 and 4. The operation of the embodiment will be described with reference to FIGS. When a predetermined operation to start the test is input, in the test piece supply device 10, the conveying device 20 uses the suction pad 29 supported by the rotating arm 26 (see Figure 1) to pick up and hold the test pieces T one by one from the pallet 11, and as shown in Figure 2, supplies the test pieces T to the upper gripper 38 of the testing device 30 and has them gripped by the upper gripper 38.

[0038] Next, the crosshead 35 is lowered, moving the upper grip 38 holding the test piece T toward the lower grip 39. As the crosshead 35 descends, the connecting frame 101, actuator 102, and pressing mechanism 104 constituting the positioning mechanism 100 descend together, until the pressing mechanism 104 abuts against the upper arm 80. As the crosshead 35 continues to descend after the pressing mechanism 104 abuts against the upper arm 80, the upper arm 80 begins to descend and abuts against the collar 96. As the crosshead 35 continues to descend, the upper arm 80 begins to press down on the lower arm 90 via the collar 96, and the lower arm 90 begins to descend together with the upper arm 80. The crosshead 35 then descends a predetermined distance and stops. As shown in FIG. 4, the test piece T enters the lower grip 39, which then grips the test piece T. The lower arm 90 then abuts against the stopper mechanism 79 and stops.

[0039] At this time, in the elongation measuring device 70, the positions of the upper arm 80 and the lower arm 90 coincide with the positions of the marked lines M1, M2 of the test piece T, and the clamping members 82 of the upper arm 80 and the clamping members 92 of the lower arm 90 are closed to fix the test piece T at equal positions above and below the center position M0 of the pair of gripping tools 38, 39. This enables the arms 80, 90 to follow the marked lines M1, M2 in accordance with the elongation of the test piece T. In addition, since the pressing mechanism 104 functions as a buffer mechanism, even if the lower arm 90 abuts against the stopper mechanism 79 and the crosshead 35 stops descending, excessive pressing on the upper arm 80 and the like is suppressed. In the elongation measuring device 70, the movement of the crosshead 35 of the testing device 30 can be used to move and position the upper arm 80 and the lower arm 90 to the marked lines M1 and M2.

[0040] 2 and 4. When the length of the test piece T is short, the distance L2 between the pair of gripping tools 38, 39 becomes shorter than the distance L1 shown in FIG. 4. Also, the distance λ2 between the gauge lines of the test piece T becomes shorter than the distance λ1 shown in FIG. 4, and the distance between the pair of arms 80, 90 becomes shorter. In this embodiment, the positioning mechanism 100 includes an actuator 102, and the positioning mechanism 100 adjusts the amount of pressing of the pair of arms 80, 90 depending on the length of the test piece T. Specifically, the position of the pressing element 104C of the pressing mechanism 104 is adjusted to a distance U2 from the upper gripping tool 39. At this time, an adjuster 78 is selectively disposed in the stopper mechanism 79. In addition, a collar 96 is selectively attached to the lower arm 90.

[0041] As a result, when the crosshead 35 descends by a predetermined amount according to the length of the test piece T, the elongation measuring device 70 can move the upper arm 80 and the lower arm 90 to different positions relative to the grippers 38 and 39 to align them with the benchmark lines M1 and M2 that are different from those of the long test piece T. Therefore, the upper arm 80 and the lower arm 90 can be fixed to the benchmark lines M1 and M2 of a short length. Therefore, in this embodiment, the positioning mechanism 100 is equipped with an actuator 102 that adjusts the amount of pushing of the pair of arms 80, 90 according to the length of the test piece T, so that the configuration of the elongation measuring device 70 is simplified, and the positional relationship between the pair of gripping tools 38, 39 and the pair of arms 80, 90 can be changed with this simple configuration.

[0042] When a test force is applied to the test piece T, the pressing mechanism 104 retracts the rod portion 104B to separate the pressing element 104C from the pressure receiving portion 86 of the upper arm 80. This allows the pressing element 104C to be in a state where it does not restrain the upper arm 80 when the test force is applied. Then, the crosshead 35 rises, and the upper gripping tool 38 moves away from the lower gripping tool 39, applying a tensile load to the test piece T. Accordingly, the test piece T is pulled by the upper gripping tool 38 and extends upward. At this time, the lower arm 90 moves upward following the movement of the marked line M2 and moves away from the stopper mechanism 79. Furthermore, the upper arm 80 moves upward following the movement of the marked line M1 and moves away from the collar 96. The pressing mechanism 104 rises together with the crosshead 35. In the materials testing machine 1, the tensile load of the test piece T is measured, and the elongation of the test piece T is measured from the fluctuation of the distance between the arms 80 and 90 during the test. 2, the stopper mechanism 79, the lower arm 90, the upper arm 80, and the pressing mechanism 104 move away from each other in the vertical direction TD, and the upper arm 80 and the lower arm 90 return to positions where they can be pressed by the positioning mechanism 100. In the pressing mechanism 104, the retracted rod portion 104B is extended, and the pressing element 104C is returned to a position for pressing the upper arm 80.

[0043] [2. Modifications] The above-described embodiment merely exemplifies one aspect of the present invention, and any modifications and applications are possible without departing from the spirit of the present invention.

[0044] In the above-described embodiment, the actuator 102 is configured as an air cylinder, and the rod portion 102B has a two-stage configuration, but the configuration may be such that the position can be adjusted to any position. For example, the actuator 102 may be configured as an electric cylinder, and the pushing amount may be adjusted to any amount.

[0045] In the above-described embodiment, the pressing mechanism 104 is provided, but the rod portion 102B of the actuator 102 may directly press the upper arm 80.

[0046] It will be understood by those skilled in the art that the exemplary embodiments and variations described above are examples of the following aspects.

[0047] (Section 1) One embodiment of a materials testing machine comprises a loading mechanism that applies a test force to a test piece held at both ends by a pair of gripping tools, and an elongation measuring device that fixes a pair of arms to a pair of marking lines on the test piece and measures the elongation between the pair of marking lines.The elongation measuring device may comprise a positioning mechanism that pushes the pair of arms in conjunction with the movement of the loading mechanism and positions the pair of arms between the pair of gripping tools, and the positioning mechanism may comprise an actuator that adjusts the amount of pushing of the pair of arms depending on the length of the test piece.

[0048] According to the material testing machine described in paragraph 1, the positioning mechanism is equipped with an actuator that adjusts the amount of pushing of the pair of arms according to the length of the test piece, so that the positional relationship between the pair of grippers and the pair of arms can be changed with a simple configuration.

[0049] (Section 2) In the material testing machine described in paragraph 1, the positioning mechanism may include a connecting frame connected to the loading mechanism, the actuator supported by the connecting frame, and an impact absorbing member connected to the actuator.

[0050] According to the material testing machine described in the second paragraph, it is possible to buffer the impact on the arm caused by contact with the actuator.

[0051] (Section 3) In the material testing machine described in paragraph 1 or 2, the pushing amount of the pair of arms may be adjusted so that the center position between the pair of arms coincides with the center position between the pair of benchmark lines of the test piece.

[0052] According to the material testing machine described in item 3, the arm can be fixed to the test piece in a well-balanced manner.

[0053] (Section 4) The material testing machine described in any one of paragraphs 1 to 3 may further comprise a test piece storage device that stores the test piece, a transport device that removes the test piece from the test piece storage device and transfers the test piece to the loading mechanism, and a control device that acquires length information of the test piece and drives the actuator based on the length information.

[0054] According to the material testing machine described in item 4, the control of the actuator can be automated, and the elongation of test pieces with different lengths can be easily measured.

[0055] (Section 5) In the material testing machine described in any one of paragraphs 1 to 4, when the pair of arms is positioned between the pair of grippers, the positioning mechanism may move the upper gripper of the pair of grippers toward the lower gripper.

[0056] According to the material testing machine described in item 5, the arm can be moved in the direction of gravity to be positioned.

[0057] The material testing machine described in paragraph 5 may further include a test piece storage device that stores the test pieces, and a transport device that removes the test pieces stored in the test piece storage device and transports the test pieces to the upper grip of the loading mechanism. According to this material testing machine, the pair of arms can be positioned by utilizing the movement of the loading mechanism at the start of the test. [Explanation of symbols]

[0058] 1. Material testing machine 12 Test specimen storage device 20. Conveyor 35 Crosshead (load mechanism) 38 Upper gripping tool 39 Lower gripping tool 70 Elongation measuring device 80 Upper Arm 90 Lower Arm 100 Positioning mechanism 101 Connecting Frame 102 Actuator 104 Pressing mechanism (shock absorbing member) M0 Center position between gauge lines M1, M2 marked line T test piece U1, U2 pushing amount

Claims

1. A materials testing machine comprising: a loading mechanism that applies a test force to a test piece gripped at both ends by a pair of gripping tools; an elongation measuring device that fixes a pair of arms to a pair of benchmark lines provided on the test piece and measures the elongation between the pair of benchmark lines; a test piece storage device that stores the test piece; a transport device that removes the test piece from the test piece storage device and transfers the test piece to the loading mechanism; and a control device that acquires length information of the test piece and drives an actuator based on the length information, the elongation measuring device includes a positioning mechanism that pushes and moves the pair of arms in conjunction with the movement of the load mechanism and positions the pair of arms between the pair of gripping tools; the positioning mechanism includes the actuator that adjusts the pushing amount of the pair of arms in accordance with the length of the test piece; The control device drives the actuator so that a predetermined pushing amount corresponding to the length of the test piece is applied when the test piece is transferred from the transport device to the loading mechanism.

2. A pallet for accommodating the test specimens, the test strip storage device is capable of storing a plurality of the pallets; 2. The materials testing machine according to claim 1, wherein the control device stores the length information for each of the pallets and drives the actuator based on the length information for each of the pallets.

3. 3. The materials testing machine according to claim 1, wherein the positioning mechanism comprises a connecting frame connected to the load mechanism, the actuator supported by the connecting frame, and an impact absorbing member connected to the actuator.

4. 4. The materials testing machine according to claim 1, wherein the actuator adjusts the amount of pushing of the pair of arms so that a center position between the pair of arms coincides with a center position between a pair of benchmark lines on the test piece.

5. 5. The materials testing machine according to claim 1, wherein the positioning mechanism moves an upper grip of the pair of grips toward a lower grip when the pair of arms is positioned between the pair of grips.

Images