A tensile strength testing device

Abstract

The utility model discloses a kind of tensile strength testing device, belong to water pump manufacturing technical field, including rack, rack is provided with tensile space, tensile space is slidably provided with tensile rod along up-down direction, the inner top wall of tensile space and the upper end surface of tensile rod are uniformly fixed with clamping mechanism. The utility model uses, first, press two clamping jaws with hand, so that two clamping jaws promote pull block to move downwards, then the end of the measured piece is placed between two clamping jaws, elastic element drives pull block to move upwards, drive two clamping jaws to move upwards, two clamping jaws are gradually closed under the action of two limit blocks and the end of the measured piece is clamped, drive device drives the clamping mechanism below to move downwards, bottom plate drives two limit blocks to move downwards, two limit blocks are limited to two clamping jaws while driving two clamping jaws to move downwards, so that two clamping jaws are clamped to the end of the measured piece while stretching the measured piece downwards, the purpose of tensile test to the measured piece is realized.

Description

Technical Field

[0001] This utility model relates to the technical field of water pump manufacturing, and in particular to a tensile strength testing device. Background Technology

[0002] In the production of water pumps, the pump casing is manufactured through casting. After the casing is manufactured, it undergoes precision machining. The machining items include the flange faces of the inlet and outlet pipes and the assembly surfaces where the casing and the rear cover are fixed together by bolts. After precision machining, the casing must also undergo an airtightness test. In the casting production of the casing, another very important performance test is the tensile test. The tensile test is conducted by sampling. The tensile test method is as follows: a casing is randomly selected, and a portion of the material from the casing is made into a test piece. The test piece is long and narrow. The test piece is installed and fixed on a tensile strength testing device for tensile testing until it breaks. The tensile force value is recorded to determine whether the tensile test of the casing material meets the standard.

[0003] Tensile strength testing devices generally include two clamping mechanisms. One clamping mechanism is static, while the other can move away from the static clamping mechanism. In use, the two ends of the workpiece to be tested are clamped onto the two clamping mechanisms respectively. Then, the movable clamping mechanism is driven away from the static clamping mechanism to achieve the stretching of the workpiece. A force sensor is also installed on the static clamping mechanism. The force sensor records the tensile force value until the workpiece breaks.

[0004] The existing clamping mechanism clamps the test piece with a fixed force. During tensile testing, one end of the test piece often detaches from the clamping mechanism, requiring the pre-fabricated part to be remade and the tensile test to be repeated, which reduces the testing efficiency of the tensile test. Utility Model Content

[0005] The purpose of this invention is to provide a tensile strength testing device. The clamping mechanism has the advantage of becoming tighter as it is pulled during the tensile test, which effectively solves the problem of the test piece detaching from the clamping mechanism during the tensile test in the prior art.

[0006] This utility model adopts the following technical solution: a tensile strength testing device, including a frame, a tensile space provided inside the frame, a tensile rod slidably arranged in the tensile space along the vertical direction, a clamping mechanism fixedly provided on the inner top wall of the tensile space and the upper end face of the tensile rod, a driving device and a transmission device installed on the frame, the driving device driving the tensile rod to move up and down through the transmission device; a tensile testing device is fixedly arranged between the clamping mechanism above and the inner top wall of the tensile space; the clamping mechanism includes a base plate fixedly arranged on the upper end face of the tensile rod, two symmetrical limiting blocks fixedly arranged on the upper end face of the base plate, a pull block slidably arranged in the vertical direction on the base plate between the two limiting blocks, and two grippers hinged on the pull block; when the pull block moves downward, it drives the two grippers to move downward relative to the two limiting blocks, so that the two grippers can open freely; when the pull block moves upward, it drives the two grippers to move upward relative to the two limiting blocks, so that the two grippers gradually close under the limitation of the two limiting blocks, and an elastic element is also provided between the pull block and the base plate, the elastic element driving the pull block to always move upward.

[0007] Furthermore, the outer surfaces of the two grippers are arc surfaces, the bottom ends of the two grippers are hinged to the pull block, and the inner surfaces of the two limiting blocks are inclined surfaces that slope from top to bottom and outward.

[0008] Furthermore, the two limiting blocks are two symmetrical parts of a frustum block. The upper end face of the frustum block has a conical hole that is larger at the bottom and smaller at the top, and the inner wall of the conical hole is the inclined surface of the limiting block.

[0009] Furthermore, the upper part of the inner side of the two grippers is provided with a clamping surface, and each clamping surface is provided with several clamping grooves along the front-back direction.

[0010] Furthermore, the pull block is fitted with a guide rod, the bottom end of which is fixedly mounted to the base plate.

[0011] Furthermore, the elastic element is a compression spring, which is sleeved on the guide rod located between the pull block and the base plate. The compression spring always pushes the pull block to move upward.

[0012] Furthermore, the upper end face of the pull block is provided with a clearance hole.

[0013] Furthermore, the transmission device includes two threaded rods, each of which is rotatably connected to the frame and threadedly connected to the tension rod. A synchronous pulley is fixedly installed at the top of each of the two threaded rods, and the two synchronous pulleys are connected by a synchronous belt.

[0014] Furthermore, the drive device includes a motor fixedly mounted on the frame, with the motor's output shaft coaxially fixed with one of the synchronous pulleys.

[0015] Furthermore, the frame includes two columns and a crossbeam fixed to the top of each of the two columns. A base is fixed to the bottom of each of the two columns. The motor is fixed to the upper surface of the crossbeam. The two ends of the tension rod are slidably connected to the corresponding columns in the vertical direction. The top of each threaded rod is rotatably connected to the crossbeam, and the bottom of each threaded rod is rotatably connected to the base. The tensioning space is the internal space enclosed by the crossbeam, the base, and the two columns.

[0016] I. This utility model, by setting up a clamping mechanism, a base plate, a limiting block, a pull block, and grippers, allows for the following operation: First, press down on the two grippers by hand, causing them to push the pull block downwards, allowing the grippers to open freely. Then, place one end of the workpiece to be tested between the two grippers and release the pressure. The elastic element drives the pull block upwards, moving the two grippers upwards as well. Under the action of the two limiting blocks, the two grippers gradually close to clamp the end of the workpiece. Finally, the drive mechanism moves the clamping mechanism downwards. The base plate moves downward, which in turn moves the two limiting blocks downward. The two limiting blocks limit the two grippers while simultaneously moving the grippers downward. This causes the two grippers to clamp one end of the test piece and pull it downward, achieving the purpose of the tensile test. During the tensile test, the base plate and the two limiting blocks move downward, while the two grippers clamping the test piece will tend to move upward relative to the two limiting blocks under the action of tension. This makes the two grippers clamp the test piece tighter as it is stretched, preventing the test piece from falling off during the stretching process.

[0017] II. This utility model features two grippers with arc-shaped outer surfaces and two limiting blocks with inclined inner surfaces. In use, the two grippers are first pressed downwards, causing the pull block to move downwards. As the pull block slides downwards relative to the two limiting blocks, the movement space of the two grippers increases, allowing them to rotate freely and open or close, thus accommodating the test piece. When the pull block slides upwards relative to the two limiting blocks, the movement space of the two grippers decreases. The inclined surfaces of the two limiting blocks force the two grippers to gradually close, clamping the test piece. During the tensile test, the two limiting blocks move downwards under the influence of the base plate. The grippers, holding the test piece, are stretched and tend to move upwards, causing the grippers to tighten under the constraint of the limiting blocks, achieving the goal of increasingly tight clamping of the test piece during the tensile test. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall three-dimensional structure of this utility model;

[0019] Figure 2 This is a front view structural diagram of the present utility model;

[0020] Figure 3This is a three-dimensional structural diagram of the clamping mechanism in this utility model;

[0021] Figure 4 This is a three-dimensional structural diagram of the synchronous belt in this utility model;

[0022] Figure 5 This is a schematic diagram of the internal three-dimensional structure of the limiting block in this utility model;

[0023] Figure 6 This is a schematic diagram of the internal three-dimensional structure of the pull block in this utility model;

[0024] Figure 7 This is a schematic diagram showing the two grippers in the upper position in this utility model;

[0025] Figure 8 This is a schematic diagram showing the state of the two grippers after they have been pressed down and moved in this utility model.

[0026] Figure 9 This is a schematic diagram of the structure of the two grippers in this utility model, showing their ability to rotate freely.

[0027] In the diagram, 1. Frame; 2. Tension rod; 3. Clamping mechanism; 4. Tension testing device; 5. Base plate; 6. Limit block; 7. Pull block; 8. Gripper; 9. Tapered hole; 10. Clamping surface; 11. Guide rod; 12. Compression spring; 13. Clearance hole; 14. Threaded rod; 15. Synchronous pulley; 16. Synchronous belt; 17. Motor; 18. Column; 19. Crossbeam; 20. Base. Detailed Implementation

[0028] Please see Figure 1-9 The present invention will now be described in detail with reference to the accompanying drawings and embodiments:

[0029] The tensile strength testing device of this utility model includes a frame 1, a tensile space is provided inside the frame 1, a tensile rod 2 is slidably arranged in the tensile space along the vertical direction, and a clamping mechanism 3 is fixedly provided on the inner top wall of the tensile space and the upper end face of the tensile rod 2. A driving device and a transmission device are installed on the frame 1. The driving device drives the tensile rod 2 to move up and down through the transmission device. A tensile testing device 4 is fixedly arranged between the upper clamping mechanism 3 and the inner top wall of the tensile space. In use, the two ends of the pre-made test piece are clamped in the upper clamping mechanism 3 and the lower clamping mechanism 3 respectively. Then, the driving device and the transmission device drive the tensile rod 2 to move downward, so that the lower clamping mechanism 3 stretches the lower end of the test piece, so as to perform a tensile test on the entire test piece until the test piece breaks under tension, and the test is completed. The tensile testing device 4 records the tensile force value and compares it with the standard value to determine whether the tensile test of the material of the test piece is qualified.

[0030] In this embodiment, the tensile testing device 4 can be a force sensor.

[0031] In this embodiment, the clamping mechanism 3 includes a base plate 5 fixedly disposed on the upper end face of the tension rod 2. Two symmetrical limiting blocks 6 are fixedly disposed on the upper end face of the base plate 5. A pull block 7 is slidably disposed on the base plate 5 between the two limiting blocks 6 in the vertical direction. Two grippers 8 are hinged on the pull block 7. When the pull block 7 moves downward, it drives the two grippers 8 to move downward relative to the two limiting blocks 6, so that the two grippers 8 can open freely. When the pull block 7 moves upward, it drives the two grippers 8 to move upward relative to the two limiting blocks 6, so that the two grippers 8 gradually close under the limitation of the two limiting blocks 6. An elastic element is also disposed between the pull block 7 and the base plate 5. The elastic element drives the pull block 7 to move upward continuously.

[0032] In use, first press down on the two grippers 8 by hand, causing them to push the pull block 7 downwards, allowing the grippers 8 to open freely. Then, place one end of the workpiece to be tested between the two grippers 8 and release. The elastic element drives the pull block 7 upwards, which in turn moves the two grippers 8 upwards. Under the action of the two limiting blocks 6, the two grippers 8 gradually close to clamp the end of the workpiece to be tested. Then, the drive device moves the tension rod 2 downwards, which in turn moves the base plate 5 downwards. The base plate 5 then moves the two limiting blocks 6 downwards. As the two limiting blocks 6 move downwards, they simultaneously limit the two grippers 8 and drive them downwards, causing the two grippers 8 to clamp one end of the test piece while stretching it downwards. This achieves the purpose of the tensile test on the test piece. During the tensile test, the tension rod 2, the base plate 5, and the two limiting blocks 6 move downwards, while the two grippers 8, holding the test piece, tend to move upwards relative to the two limiting blocks 6 under the action of tension. This causes the two grippers 8 to clamp the test piece more tightly as it is stretched, preventing the test piece from falling off during the stretching process.

[0033] In this embodiment, the outer surfaces of the two grippers 8 are arc surfaces, and the bottom ends of the two grippers 8 are hinged to the pull block 7. The inner surfaces of the two limiting blocks 6 are inclined surfaces that slope downwards and outwards. In use, the two grippers 8 are first pressed downwards, causing the pull block 7 to move downwards. When the pull block 7 slides downwards relative to the two limiting blocks 6, the range of motion of the two grippers 8 increases, as shown in the attached figure. Figure 7 , 8 9. The two grippers 8 can rotate freely, open or close, and can hold the test piece; when the pull block 7 slides upward relative to the two limit blocks 6, the activity space of the two grippers 8 is reduced, and the two limit blocks 6 force the two grippers 8 to gradually close through the inclined surface, clamping the test piece; during the tensile test, the two limit blocks 6 move downward under the action of the base plate 5, and the two grippers 8 clamping the test piece have a tendency to move upward under the tension, which makes the two grippers 8 clamp tighter and tighter under the limitation of the two limit blocks 6.

[0034] In this embodiment, the two limiting blocks 6 are two symmetrical parts of a frustum block. The upper end face of the frustum block is provided with a conical hole 9 that is larger at the lower end and smaller at the upper end. The inner wall of the conical hole 9 is the inclined surface of the limiting block 6. The inclined surface is set as the inner wall of the conical hole 9, so that the inclined surface has an inclination in the vertical direction and a set arc in the front-back direction, so that the inclined surface can better cooperate with the outer surface of the gripper 8 for limiting.

[0035] In this embodiment, the upper part of the inner side surface of the two grippers 8 is provided with a clamping surface 10, and each clamping surface 10 is provided with a plurality of clamping grooves along the front-back direction; the clamping grooves increase the clamping force.

[0036] In this embodiment, a guide rod 11 is fitted inside the pull block 7. The bottom end of the guide rod 11 is fixedly set to the base plate 5. The pull block 7 slides up and down along the guide rod 11, realizing the purpose of sliding connection between the pull block 7 and the base plate 5. At the same time, the pull block 7 and the guide rod 11 can rotate relative to each other, so that the two grippers 8 can rotate slightly during the tensile test to avoid the test piece being subjected to torque during the tensile test, thereby improving the accuracy of the tensile test.

[0037] In this embodiment, the elastic element is a compression spring 12. The compression spring 12 is sleeved on the guide rod 11 located between the pull block 7 and the base plate 5. The compression spring 12 always pushes the pull block 7 to move upward until the two grippers 8 are fully closed. After the two grippers 8 are closed, the pull block 7 stops moving upward, thus achieving the limit of the upward movement of the pull block 7.

[0038] In this embodiment, the upper end face of the pull block 7 is provided with a clearance hole 13. When the pull block 7 moves up and down along the guide rod 11, the guide rod 11 passes through the clearance hole 13 and does not interfere with the up and down sliding of the pull block 7.

[0039] In this embodiment, the transmission device includes two threaded rods 14, each threaded rod 14 is rotatably connected to the frame 1, and each threaded rod 14 is threadedly connected to the tension rod 2. The top ends of the two threaded rods 14 are fixedly provided with synchronous pulleys 15, and the two synchronous pulleys 15 are connected by a synchronous belt 16.

[0040] In this embodiment, the driving device includes a motor 17 fixedly mounted on the frame 1. The output shaft of the motor 17 is coaxially fixedly mounted with one of the synchronous pulleys 15. In use, the motor 17 drives one of the synchronous pulleys 15 to rotate. The synchronous pulley 15 drives the other synchronous pulley 15 to rotate synchronously through the synchronous belt 16. The two synchronous pulleys 15 drive the two threaded rods 14 to rotate synchronously. The two threaded rods 14 drive the tension rod 2 to move up and down, thereby driving the tension rod 2 to move up and down.

[0041] In this embodiment, the frame 1 includes two columns 18 and a crossbeam 19 fixedly disposed at the top of each of the two columns 18. A base 20 fixedly disposed at the bottom of each of the two columns 18 is provided below the two columns 18. The motor 17 is fixedly disposed on the upper end face of the crossbeam 19. The two ends of the tension rod 2 are slidably connected to the corresponding columns 18 in the vertical direction. The top of each threaded rod 14 is rotatably connected to the crossbeam 19, and the bottom of each threaded rod 14 is rotatably connected to the base 20. The tensioning space is the internal space enclosed by the crossbeam 19, the base 20, and the two columns 18.

[0042] The working principle of this utility model is as follows: First, press the two grippers 8, causing the two grippers 8 to drive the pull block 7 downward, so that the two grippers 8 can rotate freely within the two limiting blocks 6. Open the two grippers 8, put in the test piece, and then release. The compression spring 12 pushes the pull block 7 upward, so that when the two grippers 8 slide upward relative to the two limiting blocks 6, the two limiting blocks 6 force the two grippers 8 to gradually close through the inclined surface, clamping the test piece. The top end of the test piece is clamped by the two grippers 8 below, and the bottom end of the test piece is clamped by the two grippers 8 below. Then, the motor 17 drives the tension rod 2 to move downward, and the tension rod 2 drives the two limiting blocks 6 of the base plate 5 to move downward, thereby increasing the clamping force of the two grippers 8 on the test piece and simultaneously pulling the test piece downward until the test piece breaks, completing the test. The tensile testing device 4 records the tensile force value and compares it with the standard value to determine whether the tensile test of the material of the test piece is qualified.

Claims

1. A tensile strength testing device characterized by: The device includes a frame (1), a stretching space is provided inside the frame (1), a stretching rod (2) is slidably arranged in the stretching space along the vertical direction, a clamping mechanism (3) is fixedly provided on the inner top wall of the stretching space and the upper end face of the stretching rod (2), a driving device and a transmission device are installed on the frame (1), the driving device drives the stretching rod (2) to move up and down through the transmission device; a stretching detection device (4) is fixedly provided between the clamping mechanism (3) above and the inner top wall of the stretching space; the clamping mechanism (3) includes a base plate (5) fixedly provided on the upper end face of the stretching rod (2), and two symmetrical limiting blocks (6) are fixedly provided on the upper end face of the base plate (5). A pull block (7) is slidably provided on the bottom plate (5) between the two limiting blocks (6) in the vertical direction. Two grippers (8) are hinged on the pull block (7). When the pull block (7) moves downward, it drives the two grippers (8) to move downward relative to the two limiting blocks (6), so that the two grippers (8) can open freely. When the pull block (7) moves upward, it drives the two grippers (8) to move upward relative to the two limiting blocks (6), so that the two grippers (8) gradually close under the limitation of the two limiting blocks (6). An elastic element is also provided between the pull block (7) and the bottom plate (5). The elastic element drives the pull block (7) to move upward all the time.

2. The tensile strength testing device of claim 1, wherein: The outer surfaces of the two grippers (8) are arc surfaces, the bottom ends of the two grippers (8) are hinged to the pull block (7), and the inner surfaces of the two limiting blocks (6) are inclined surfaces that slope from top to bottom and outward.

3. The tensile strength testing device of claim 2, wherein: The two limiting blocks (6) are two symmetrical parts of a frustum block. The upper end of the frustum block has a conical hole (9) with a larger lower end and a smaller upper end. The inner wall of the conical hole (9) is the inclined surface of the limiting block (6).

4. The tensile strength testing device of claim 1, wherein: The upper part of the inner side of the two grippers (8) is provided with a clamping surface (10), and each clamping surface (10) is provided with several clamping grooves along the front-back direction.

5. The tensile strength testing device of claim 1, wherein: The pull block (7) is fitted with a guide rod (11), and the bottom end of the guide rod (11) is fixedly set with the base plate (5).

6. The tensile strength testing device of claim 5, wherein: The elastic element is a compression spring (12), which is sleeved on the guide rod (11) located between the pull block (7) and the base plate (5). The compression spring (12) always pushes the pull block (7) to move upward.

7. The tensile strength testing device of claim 1, wherein: The upper end face of the pull block (7) is provided with a clearance hole (13).

8. The tensile strength testing device of claim 1, wherein: The transmission device includes two threaded rods (14), each threaded rod (14) is rotatably connected to the frame (1), each threaded rod (14) is threadedly connected to the tension rod (2), and the top of each threaded rod (14) is fixedly provided with a synchronous pulley (15), and the two synchronous pulleys (15) are connected by a synchronous belt (16).

9. The tensile strength testing device of claim 8, wherein: The drive device includes a motor (17) fixedly mounted on the frame (1), and the output shaft of the motor (17) is fixedly mounted coaxially with one of the synchronous pulleys (15).

10. The tensile strength testing device of claim 9, wherein: The frame (1) includes two columns (18) and a crossbeam (19) fixed to the top of each of the two columns (18). A base (20) is fixed to the bottom of each of the two columns (18) below the two columns (18). The motor (17) is fixed to the upper end of the crossbeam (19). The two ends of the tension rod (2) are slidably connected to the corresponding column (18) in the vertical direction. The top of each threaded rod (14) is rotatably connected to the crossbeam (19), and the bottom of each threaded rod (14) is rotatably connected to the base (20). The tensioning space is the internal space enclosed by the crossbeam (19), the base (20), and the two columns (18).

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