A universal tensile testing device

Abstract

This invention relates to the field of mechanical property testing technology, specifically to a universal tensile testing device, comprising a frame; a clamping assembly and two bidirectional helical shafts arranged side-by-side in the left-right direction are mounted on the frame; the clamping assembly is used to clamp and stretch the workpiece; the two bidirectional helical shafts can rotate synchronously and in the same direction under the action of a synchronous rotation assembly; each bidirectional helical shaft has two helical protrusions with opposite directions of rotation; a hydraulic cylinder is helically sleeved on each helical protrusion, and a first piston, a second piston, and a third piston are sequentially inserted into each hydraulic cylinder from the outside to the inside; the relative position between the first piston and the bidirectional helical shaft remains unchanged; the first piston is connected to the second piston through a first elastic element, and the third piston is connected to the hydraulic cylinder through a second elastic element; a top block is fixedly mounted on each third piston, and the top block can form a stop engagement with the workpiece. Thus, hydraulic pressure can be used to automatically vertically correct the workpiece through the top block.

Description

Technical Field

[0001] This invention relates to the field of mechanical performance testing technology, and in particular to a universal tensile testing device. Background Technology

[0002] In modern industrial manufacturing, the quality of workpieces directly affects the overall performance and service life of products. After the workpiece is processed, tensile testing is a key step in quality inspection. By measuring core indicators such as yield strength, tensile strength, and elongation, it can accurately reflect the workpiece's plastic deformation capacity and mechanical properties during the stress process. These parameters are not only important bases for evaluating the material properties of workpieces, but also the foundation for ensuring the safety and reliability of products in practical applications. They play a decisive role in guiding the optimization of production processes and ensuring the quality of industrial products.

[0003] When performing tensile tests on workpieces, relevant testing equipment is required. In related technologies, such as Chinese patent CN113834724B, a tensile mechanical property testing device for medium strain rate materials is disclosed. When using this device, the sample is first clamped by a first sample holder and a second sample holder, and then the second sample holder is moved downward to stretch the sample.

[0004] However, the aforementioned tensile mechanical property testing device for medium strain rate materials also has some problems in actual use: when clamping strip-shaped and dumbbell-shaped workpieces, it is difficult to accurately control the spatial position of the workpiece due to the reliance on manual placement; and due to the influence of factors such as the operator's experience level, operating environment, and visual errors, the workpiece is very easy to deviate from the vertical reference state, resulting in the tensile axis not being completely coincident with the geometric center line of the workpiece. In the subsequent tensile test, this initial clamping deviation will introduce additional bending moment and shear force, causing uneven stress on the workpiece, which in turn causes a large deviation between the key data such as yield strength and tensile strength obtained from the test and the true value, seriously affecting the accuracy and reliability of the test results, and failing to provide effective data support for workpiece quality assessment. Summary of the Invention

[0005] Therefore, it is necessary to provide a universal tensile testing device to address the problem of poor accuracy in current tensile testing of workpieces.

[0006] The above objectives are achieved through the following technical solutions:

[0007] A universal tensile testing device includes a frame; the frame is equipped with a clamping assembly and two bidirectional helical shafts, the clamping assembly being configured to clamp and stretch a workpiece; the two bidirectional helical shafts are arranged side-by-side in a left-right direction and can rotate synchronously and in the same direction under the action of a synchronous rotation assembly; each bidirectional helical shaft has two helical protrusions with opposite directions of rotation; a hydraulic cylinder is helically sleeved on each helical protrusion, and a first piston, a second piston, and a third piston are sequentially slidably inserted into each hydraulic cylinder from the outside to the inside, the relative position between the first piston and the bidirectional helical shaft remains unchanged, the first piston is connected to the second piston through a first elastic element, and the third piston is connected to the second piston through a first elastic element. The second elastic element is connected to the hydraulic cylinder body. A first hydraulic chamber is formed between the first piston and the hydraulic cylinder body, and a second hydraulic chamber is formed between the second piston and the third piston. The first hydraulic chamber and the second hydraulic chamber within the same hydraulic cylinder body are interconnected. In different hydraulic cylinder bodies, two first hydraulic chambers located on the same left or right side are interconnected. The third piston can block the connection between the second hydraulic chamber and the first hydraulic chamber. Each third piston is fixedly provided with a top block, which is located outside the hydraulic cylinder body and can form a stop with the workpiece. Two top blocks located on the same front or rear side are initially located in the same vertical plane.

[0008] Furthermore, the clamping assembly includes two fixed shafts arranged vertically and movable in directions away from or close to each other; each fixed shaft is fitted with a rotating sleeve that can rotate around its own axis; each rotating sleeve is threaded with a clamping seat, which forms a stop fit with the fixed shaft; each clamping seat contains two wedge-shaped clamping blocks, which are simultaneously fitted onto the fixed shaft, forming a wedge-shaped clamping structure with the two wedge-shaped clamping blocks and the clamping seat. The wedge-shaped clamping structure is V-shaped, with the smaller opening facing the other clamping seat, and the two wedge-shaped clamping blocks are configured to clamp the workpiece.

[0009] Furthermore, one of the clamping seats is provided with two support shafts, which are arranged side by side in the left-right direction; each support shaft has two connecting rods sleeved at both ends, and on different support shafts, two connecting rods located on the same front side or the same rear side form a figure-eight structure, with the smaller opening facing the other clamping seat; the connecting rods can elastically rotate around the support shaft under the action of the elastic rotation component; the bidirectional spiral shaft is inserted on two connecting rods located on the same left side or the same right side of different support shafts; each bidirectional spiral shaft is provided with a clamping part, which is configured to clamp the workpiece; under the action of the elastic rotation component, the two bidirectional spiral shafts can move along a figure-eight trajectory; each of the first pistons is fixedly connected to the connecting rods through a connecting frame.

[0010] Furthermore, the elastic rotation assembly includes a first support rod, a second support rod, and a third elastic element. Two first support rods are provided on the clamping seat where the support shaft is located, arranged side-by-side in the left-right direction. Two second support rods are respectively connected to two connecting rods located on the same left and right sides of different support shafts, arranged side-by-side in the left-right direction. The third elastic element connects to both the first and second support rods located on the same left or right side.

[0011] Furthermore, the clamping part includes a plurality of clamping blocks, which are arranged along the extension direction of the bidirectional spiral shaft; the clamping blocks are elliptical in structure and are rotatably sleeved on the bidirectional spiral shaft; adjacent clamping blocks are perpendicular and fixedly connected.

[0012] Furthermore, the frame is provided with four first sliding grooves, each of which is divided into two groups. The two groups of first sliding grooves are respectively arranged on the front and rear sides of the clamping seat. The two first sliding grooves in the same group are arranged side by side in the left and right direction, forming a figure-eight structure, with the smaller opening facing upward. The bidirectional spiral shaft is slidably inserted into two first sliding grooves in different groups, located on the same left or right side.

[0013] Furthermore, each of the connecting rods is provided with a handle.

[0014] Furthermore, the synchronous rotation assembly includes a sliding block disposed on the frame and capable of elastic sliding in the vertical direction; a rotating shaft is inserted into the sliding block, the rotating shaft being parallel to the bidirectional spiral shaft and capable of rotating around its own axis; a first transmission wheel is fixedly sleeved on the rotating shaft; a second transmission wheel is fixedly sleeved on each of the bidirectional spiral shafts; and an elastic ring belt is sleeved on the first transmission wheel and the two second transmission wheels for common transmission.

[0015] Furthermore, both the first transmission wheel and the second transmission wheel are gear structures; the inner peripheral wall of the elastic ring belt is provided with ring teeth, which mesh with both the first transmission wheel and the second transmission wheel.

[0016] Furthermore, a handwheel is fixedly sleeved on the rotating shaft.

[0017] The beneficial effects of this invention are:

[0018] This invention relates to a universal tensile testing device. It comprises two bidirectional helical shafts, each with two helical protrusions in opposite directions. A hydraulic cylinder is helically fitted onto each helical protrusion, and a first piston, second piston, third piston, and a top block are provided to cooperate with it. Before testing, the helical engagement between the helical protrusions and the hydraulic cylinders causes all the hydraulic cylinders to move inward. Since the relative position between the first piston and the bidirectional helical shaft remains unchanged, the volume of the first hydraulic chamber decreases, and hydraulic oil is supplied to the second hydraulic chamber. Under the push of the hydraulic oil, the second and third pistons move away from each other. If the workpiece is tilted, the two top blocks on the same side and... The contact time of the workpiece is different. The first contact block of the workpiece, pushed by the workpiece, drives the third piston closer to the second piston, and then seals the connection between the second hydraulic chamber and the first hydraulic chamber. At this time, the hydraulic pressure in the second hydraulic chamber remains unchanged. As the hydraulic cylinder continues to move, the first contact block of the workpiece drives the workpiece to rotate. The hydraulic oil in the first hydraulic chamber flows to the first hydraulic chamber in the other hydraulic cylinder, and then flows into the second hydraulic chamber in the other hydraulic cylinder, accelerating the other block to move closer to the workpiece. When the two blocks are in the same vertical plane again, the workpiece is in a vertical state, which can automatically correct the verticality of the workpiece and improve the accuracy of the tensile test results.

[0019] Furthermore, by setting up a clamping part and a cooperating elastic rotating component, the two bidirectional spiral shafts can move along a figure-eight trajectory under the action of the elastic rotating component, and thus the workpiece can be clamped by the clamping part. This allows the clamping force to be adaptively adjusted according to the thickness of the workpiece, ensuring the stability of the workpiece during subsequent vertical correction. Attached Figure Description

[0020] Figure 1 This is a three-dimensional structural schematic diagram of the universal tensile testing device provided in an embodiment of the present invention;

[0021] Figure 2 This is a three-dimensional cross-sectional view of the universal tensile testing device provided in an embodiment of the present invention;

[0022] Figure 3 for Figure 2 A magnified schematic diagram of the structure at point Y in the middle;

[0023] Figure 4 This is a front view schematic diagram of the universal tensile testing device provided in an embodiment of the present invention;

[0024] Figure 5 A three-dimensional structural diagram of a portion of the universal tensile testing device provided in an embodiment of the present invention;

[0025] Figure 6 for Figure 5 The diagram shows a cross-sectional view of the structure.

[0026] Figure 7 The working state of a portion of the structure of the universal tensile testing device provided in the embodiments of the present invention. Figure 1 ;

[0027] Figure 8 The working state of a portion of the structure of the universal tensile testing device provided in the embodiments of the present invention. Figure 2 ;

[0028] Figure 9 This is a front view schematic diagram of a portion of the universal tensile testing device provided in an embodiment of the present invention;

[0029] Figure 10 for Figure 9 A magnified schematic diagram of the structure at point Z in the middle;

[0030] Figure 11 A three-dimensional cross-sectional view of a portion of the universal tensile testing device provided in an embodiment of the present invention during vertical alignment of a workpiece.

[0031] Figure 12 A three-dimensional structural diagram of a portion of the universal tensile testing device provided in an embodiment of the present invention;

[0032] Figure 13 for Figure 12 The diagram shows the front view of the structure.

[0033] Figure 14 for Figure 13 Sectional view along the AA direction.

[0034] in:

[0035] 1. Frame; 101. Crossbeam; 1011. First slide groove; 1012. Third notch; 1013. Guide rod; 1014. Compression spring; 102. Sliding plate; 2. Clamping assembly; 201. Fixed shaft; 2011. Limiting block; 2012. Insert rod; 202. Rotating sleeve; 2021. Handrail; 203. Clamping seat; 2031. First notch; 2032. First wedge surface; 2033. Second notch; 2034. Mounting block; 204. Wedge-shaped clamping block; 2041. Second wedge surface; 2042. Insertion hole; 205. Mounting seat; 206. Locking pin; 207. Stop bar; 3. Bidirectional spiral shaft; 301. Spiral protrusion; 4. Synchronous rotation assembly; 401 1. Sliding block; 402. Rotating shaft; 403. First transmission wheel; 404. Second transmission wheel; 405. Elastic ring belt; 406. Handwheel; 5. Hydraulic cylinder body; 501. Connecting block; 6. First piston; 7. Second piston; 8. Third piston; 9. First spring; 10. Second spring; 11. First hydraulic chamber; 12. Second hydraulic chamber; 13. Top block; 14. Support shaft; 15. Connecting rod; 1501. Handle; 16. Elastic rotating assembly; 1601. First support rod; 1602. Second support rod; 1603. Tension spring; 17. Clamping part; 1701. Clamping block; 18. Connecting frame; 19. First connecting pipe; 20. Second connecting pipe. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0037] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0038] The following reference Figures 1 to 14 The universal tensile testing device provided in this embodiment of the invention is particularly suitable for tensile testing of strip-shaped workpieces and dumbbell-shaped workpieces. Of course, it is also suitable for tensile testing of workpieces that are similar to strip-shaped workpieces and dumbbell-shaped workpieces.

[0039] Specifically, in the universal tensile testing device provided in this embodiment of the invention, it is configured to include a frame 1, which has a U-shaped main structure; a clamping assembly 2 is inserted inside the U-shape of the main structure, the clamping assembly 2 is used to clamp and stretch the workpiece, and includes two fixed shafts 201, which are arranged side by side in the vertical direction and extend in the vertical direction; a rotating sleeve 202 is rotatably sleeved on each fixed shaft 201; a clamping seat 203 is threadedly sleeved on each rotating sleeve 202, the clamping seat 203 has a C-shaped structure and has a first notch 2031, wherein the clamping seat 203 located at the top is first notched during installation. The notch 2031 is set downwards, and the clamping seat 203 located below is set upwards during installation. The rear side of the clamping seat 203 is sealed. During installation, the end of the fixed shaft 201 is inserted into the first notch 2031, and a square limiting block 2011 is set at this end. The side wall of the limiting block 2011 coincides with the front side wall of the clamping seat 203, thereby forming a stop engagement to restrict the rotation of the clamping seat 203. Then, when the rotating sleeve 202 rotates, through the threaded engagement with the clamping seat 203, the clamping seat 203 can be driven to slide up and down in the vertical direction, which is convenient for fine adjustment of the position of the clamping seat 203 in the vertical direction.

[0040] Fixed shaft 201 is connected to frame 1 via the following structure:

[0041] A sliding plate 102 is also inserted inside the U-shaped part of the main structure. The surface of the sliding plate 102 is horizontal and located below the fixed shaft 201 located below. The fixed shaft 201 located above is fixed to the inner top wall of the main structure by the mounting base 205 and the locking pin 206 during installation. The fixed shaft 201 located below is fixed to the top surface of the sliding plate 102 by the mounting base 205 and the locking pin 206 during installation. The mounting base 205 is fixedly connected to the main structure or the sliding plate 102 by bolts during installation. The locking pin 206 is inserted into both the mounting base 205 and the fixed shaft 201 during installation.

[0042] At each first notch 2031, two opposing inner sidewalls are both first wedge surfaces 2032. The two first wedge surfaces 2032 on the same clamping seat 203 form a figure-eight structure, with the smaller opening facing the other clamping seat 203. Two wedge-shaped clamping blocks 204 are inserted into each first notch 2031. The two wedge-shaped clamping blocks 204 in the same clamping seat 203 are arranged horizontally in the left-right direction. The right side wall of the wedge-shaped clamping block 204 on the left and the left side wall of the wedge-shaped clamping block 204 on the right are both vertical surfaces and can be clamped onto the two plates of the workpiece respectively. The left side wall of the wedge-shaped clamping block 204 on the left and the right side wall of the wedge-shaped clamping block 204 on the right are both second wedge surfaces 2041. 2041 is parallel to the adjacent first wedge surface 2032. The two second wedge surfaces 2041 on the two wedge-shaped clamping blocks 204 in the same clamping seat 203 form a figure-eight structure, with the small opening facing the other clamping seat 203. The two first wedge surfaces 2032 and the two second wedge surfaces 2041 on the same side all form a wedge clamping structure. Taking the clamping seat 203 located above as an example, when the clamping seat 203 moves upward, the two wedge-shaped clamping blocks 204 will move closer to each other under the action of the wedge clamping structure, so as to clamp the workpiece. When the clamping seat 203 moves downward, the two wedge clamping blocks 204 can move away from each other under the action of the wedge clamping structure, so as to loosen the clamping of the workpiece and facilitate the removal of the workpiece.

[0043] To facilitate the limiting of the wedge-shaped clamping blocks 204, an insertion hole 2042 is provided through the front side wall of each wedge-shaped clamping block 204. The insertion hole 2042 also penetrates the inner side wall of the wedge-shaped clamping block 204. An insertion rod 2012 is provided at the end of each limiting block 2011 away from the fixed axis 201. The insertion rod 2012 has a T-shaped structure. During installation, the large end of the insertion rod 2012 is simultaneously inserted into the two insertion holes 2042 on the two wedge-shaped clamping blocks 204 in the same clamping seat 203. With the cooperation of the insertion rod 2012 and the insertion hole 2042, the wedge-shaped clamping block 204 has a vertical direction. The position is determined; on the front side wall of each clamping seat 203, a second notch 2033 is provided at the position corresponding to the first wedge surface 2032. The second notch 2033 penetrates the first wedge surface 2032. The two second notches 2033 are symmetrically arranged. A stop bar 207 is fixedly inserted into each second notch 2033 by bolts. The inner end of the stop bar 207 extends inward to form a stop fit with the front side wall of the wedge-shaped clamping block 204. At the same time, the rear side wall of the wedge-shaped clamping block 204 coincides with the front side wall of the clamping seat 203, thereby preventing the wedge-shaped clamping block 204 from sliding out of the first notch 2031.

[0044] To facilitate the stretching of the workpiece, the sliding plate 102 is designed to slide vertically. After the four wedge-shaped clamps 204 clamp both ends of the workpiece, the sliding plate 102 slides downward. The sliding plate 102, through the mounting base 205, locking pin 206, fixed shaft 201, and wedge-shaped clamps 204 located below, moves the lower end of the workpiece downward. Since the upper end of the workpiece is held by the two wedge-shaped clamps 204 located above, the two ends of the workpiece will move away from each other, thus enabling the tensile force test of the workpiece. It can be understood that the power source driving the sliding plate 102 can be a common type of drive, such as an electric motor, internal combustion engine, or drive cylinder. The power source can be centralized, transmitting power to other components through a transmission structure; or it can be distributed, with multiple distributed power sources driving the actions of various components. Taking a hydraulic cylinder as the power source as an example, the hydraulic cylinder is installed on the inner bottom wall of the main structure, with the output shaft facing upward and fixed to the bottom of the sliding plate 102, ensuring that the sliding plate 102 can be driven to slide in the vertical direction.

[0045] In the field of workpiece tensile testing, when clamping strip-shaped and dumbbell-shaped workpieces, it is difficult to accurately control the spatial position of the workpiece due to the reliance on manual placement. Moreover, the workpiece is easily deviated from the vertical reference state due to factors such as the operator's experience level, operating environment, and visual errors. This causes the tensile axis to not completely coincide with the geometric center line of the workpiece. In the subsequent tensile test, this initial clamping deviation will introduce additional bending moment and shear force, resulting in uneven stress on the workpiece. Consequently, the key data such as yield strength and tensile strength obtained by the test will deviate significantly from the true values, seriously affecting the accuracy and reliability of the test results and failing to provide effective data support for workpiece quality assessment.

[0046] Based on this, in the universal tensile testing device provided in this embodiment of the invention, a crossbeam 101 is fixedly installed on both the front and rear side walls of the frame 1, and the two crossbeams 101 are located on the same horizontal plane; two bidirectional spiral shafts 3 are jointly installed on the two crossbeams 101, the bidirectional spiral shafts 3 extend horizontally in the front-back direction and can rotate around their own axis, and the two bidirectional spiral shafts 3 are arranged side by side in the left-right direction; each bidirectional spiral shaft 3 has two spiral protrusions 301 with opposite directions of rotation; a connecting block 501 is spirally sleeved on each spiral protrusion 301, and a hydraulic cylinder 5 is fixedly inserted in the connecting block 501. The hydraulic cylinder 5 has a cylindrical structure and is parallel to the bidirectional spiral shaft 3; in each hydraulic cylinder 5, a first piston 6, a second piston 7 and a third piston 8 are slidably inserted from the outside to the inside, wherein the first piston 6 has a T-shaped structure and the large end is slidably inserted in the hydraulic cylinder. The first piston 6 and the double-sided spiral shaft 3 are connected inside the cylinder body 5 and form a piston engagement with the hydraulic cylinder body 5. The small end passes through the outer end of the hydraulic cylinder body 5 and can be fixed on the clamping seat 203 located above, so that the relative position between the first piston 6 and the double-sided spiral shaft 3 remains unchanged. When the double-sided spiral shaft 3 rotates, the connecting block 501 can drive the hydraulic cylinder body 5 to move axially through the spiral engagement with the double-sided spiral shaft 3. The second piston 7 is a circular plate structure and is coaxially and slidably inserted into the hydraulic cylinder body 5, forming a piston engagement with the hydraulic cylinder body 5. The third piston 8 is a T-shaped structure, with the large end slidably inserted into the hydraulic cylinder body 5 and forming a piston engagement with the hydraulic cylinder body 5. The small end passes through the inner end of the hydraulic cylinder body 5 and is fixedly connected to a top block 13. The top block 13 can abut against the side wall in the thickness direction of the workpiece and can form a stop engagement with the workpiece to ensure that the workpiece can be driven to rotate, so as to facilitate the vertical correction of the workpiece.

[0047] Initially, the positions of the first piston 6, the second piston 7, and the third piston 8 within different hydraulic cylinders 5 relative to the hydraulic cylinder 5 are consistent. The two top blocks 13 located on the same front or rear side are initially positioned in the same vertical plane, ensuring a unified correction reference. Under the action of the synchronous rotation assembly 4, the two bidirectional spiral shafts 3 can rotate synchronously and in the same direction. Furthermore, the two spiral protrusions 301 on the two bidirectional spiral shafts 3 located on the same front or rear side have the same rotation direction. When the two bidirectional spiral shafts 3 rotate synchronously and in the same direction, they can both drive all the hydraulic cylinders 5 to move synchronously inward through the connecting block 501 to perform vertical correction of the workpiece, and also drive all the hydraulic cylinders 5 to move synchronously outward through the connecting block 501 to achieve reset, avoiding interference with the next vertical correction of the workpiece.

[0048] To ensure that the second piston 7 always forms a piston engagement with the hydraulic cylinder 5, at least one second sliding groove is provided on the inner circumferential wall of the hydraulic cylinder 5. The second sliding groove has a strip-shaped structure and extends in a direction parallel to the axis of the hydraulic cylinder 5. At least one sliding protrusion is provided on the circumferential side wall of the second piston 7. During installation, the sliding protrusion is slidably inserted into the second sliding groove, thereby ensuring that the second piston 7 has only axial freedom through the engagement between the sliding protrusion and the second sliding groove. When there are two or more second sliding grooves, all the second sliding grooves are arranged circumferentially; similarly, when there are two or more sliding protrusions, all the sliding protrusions are arranged circumferentially and are slidably inserted into the second sliding grooves respectively.

[0049] A first hydraulic chamber 11 is formed between the large end of the first piston 6 and the outer end of the hydraulic cylinder 5. A second hydraulic chamber 12 is formed between the inner end of the second piston 7 and the large end of the third piston 8. Both the first hydraulic chamber 11 and the second hydraulic chamber 12 are filled with hydraulic oil. The first hydraulic chamber 11 and the second hydraulic chamber 12 in the same hydraulic cylinder 5 are interconnected by a first connecting pipe 19. In different hydraulic cylinders 5, two first hydraulic chambers 11 located on the same left or right side are interconnected by a second connecting pipe 20. A first elastic element is connected between the large end of the first piston 6 and the second piston 7. The first elastic element can be set as a first spring 9. The setting of the first spring 9 allows the second piston 7 to slide elastically along the axial direction relative to the first piston 6. A second elastic element is connected between the large end of the third piston 8 and the inner end of the hydraulic cylinder 5. The second elastic element can be set as a second spring 10. The setting of the second spring 10 allows the third piston 8 to slide elastically along the axial direction relative to the hydraulic cylinder 5.

[0050] Initially, the two clamping seats 203 are set far apart from each other.

[0051] Before testing, the upper end of the workpiece is first placed between the two upper wedge-shaped clamping blocks 204. Then, the upper rotating sleeve 202 is rotated. The rotating sleeve 202 is threaded with the clamping seat 203 and, under the stop engagement between the clamping seat 203 and the limit block 2011, drives the upper clamping seat 203 to move upward, thereby pre-clamping the upper end of the workpiece through the upper wedge-shaped clamping structure. Then, the hydraulic cylinder is activated. The hydraulic cylinder drives the lower clamping seat 203 to move upward through the sliding plate 102 until the lower end of the workpiece is inserted between the two lower wedge-shaped clamping blocks 204. Then, the above clamping process is repeated, thereby pre-clamping the lower end of the workpiece through the lower wedge-shaped clamping structure.

[0052] Then, under the action of the synchronous rotation component 4, the two bidirectional spiral shafts 3 are driven to rotate synchronously and in the same direction. Under the spiral engagement between the spiral protrusion 301 and the connecting block 501, and under the limiting engagement between the first piston 6 and the clamping seat 203, the hydraulic cylinder 5 begins to move inward. During the inward movement of the hydraulic cylinder 5, taking the two hydraulic cylinders 5 located on the front side as an example, since the relative position between the first piston 6 and the bidirectional spiral shaft 3 remains unchanged, the first hydraulic chamber 11 is compressed, and the hydraulic oil in the first hydraulic chamber 11 moves into the second hydraulic chamber 12. Under the action of hydraulic pressure, the second piston 7 and the third piston 8 move away from each other. The third piston 8 synchronously drives the top block 13 to move inward to get closer to the workpiece. The first spring 9 and the second spring 10 are both compressed and stored.

[0053] If the workpiece is tilted, the two top blocks 13 on the same front side will contact the workpiece at different times. When one of the top blocks 13 contacts the workpiece first, it forms a stop with the workpiece. As the hydraulic cylinder 5 continues to move, the top block 13, pushed by the workpiece, drives the third piston 8 closer to the second piston 7. The second spring 10 is released until it blocks the connection between the second hydraulic chamber 12 and the first hydraulic chamber 11. At the same time, under hydraulic pressure, the second piston 7 continues to move outward until it compresses the first spring 9 to its limit. During this process, the setting of the first spring 9 prevents the hydraulic oil in the hydraulic cylinder 5 from being directly transmitted to the adjacent hydraulic cylinder 5 through the second connecting pipe 20, causing the top block 13 on it to move outward at an accelerated speed, affecting the straightening effect on the workpiece. After the third piston 8 blocks the connection between the second hydraulic chamber 12 and the first hydraulic chamber 11, the oil in the second hydraulic chamber 12... The hydraulic pressure remains constant. As the hydraulic cylinder 5 continues to move, the top block 13 that first contacts the workpiece causes the workpiece to rotate. The hydraulic oil in the first hydraulic chamber 11 flows through the second connecting pipe 20 to the first hydraulic chamber 11 in the adjacent hydraulic cylinder 5, and accelerates the other top block 13 to move closer to the workpiece. When the top block 13 and the workpiece form a stop engagement, as the hydraulic cylinder 5 continues to move, the top block 13, pushed by the workpiece, causes the third piston 8 to move closer to the second piston 7. The second spring 10 is released until the connection between the second hydraulic chamber 12 and the first hydraulic chamber 11 is blocked. At this time, the positions of the first piston 6, the second piston 7 and the third piston 8 in the two hydraulic cylinders 5 are consistent with the hydraulic cylinder 5. The two top blocks 13 are once again in the same vertical plane, so that the workpiece is in a vertical state. This allows for automatic vertical correction of the workpiece, which helps to improve the accuracy of the tensile test results.

[0054] Then, under the action of the synchronous rotation component 4, the two bidirectional spiral shafts 3 are driven to rotate synchronously and in the same direction, realizing the reset of the hydraulic cylinder body 5; under the action of the first spring 9, the second piston 7 is reset; under the action of the second spring 10, the third piston 8 and the top block 13 are reset. Then, the two rotating sleeves 202 are rotated respectively. The rotating sleeves 202 are threadedly engaged with the clamping seats 203, and under the stop engagement between the clamping seats 203 and the limit block 2011, the two clamping seats 203 are driven to move away from each other, thereby clamping the two ends of the workpiece through the two wedge clamping structures. Then, the hydraulic cylinder is activated. The hydraulic cylinder drives the clamping seat 203 located below to move downward through the sliding plate 102, so that the two pairs of wedge clamping blocks 204 move away from each other, synchronously stretching the two ends of the workpiece to realize the tensile force test of the workpiece.

[0055] In a further embodiment, to further improve the accuracy of the tensile test results, two mounting blocks 2034 are provided on the upper clamping seat 203. The two mounting blocks 2034 are symmetrically arranged on two opposite arc-shaped sidewalls of the clamping seat 203. A support shaft 14 is inserted into each mounting block 2034. The support shaft 14 is parallel to the bidirectional spiral shaft 3, and the two support shafts 14 are symmetrically arranged. Two connecting rods 15 are vertically sleeved at both ends of each support shaft 14. The connecting rods 15 are located near the upper end of the support shaft 14. The two connecting rods 15 on the same support shaft 14 are symmetrically arranged. On different support shafts 14, the two connecting rods 15 located on the same front side or the same rear side form a figure-eight structure, with the smaller opening facing the other clamping seat 203. The bidirectional spiral shaft 3 is inserted into two connecting rods 15 on different support shafts 14, located on the same left side or the same right side, and the bidirectional spiral shaft 3 is located near the lower end of the connecting rod 15.

[0056] Each bidirectional helical shaft 3 has a clamping part 17 at its center. The clamping part 17 can be configured as a ring structure made of elastic material, such as rubber. During installation, the clamping part 17 is sleeved on the bidirectional helical shaft 3 to ensure elastic clamping of the workpiece, avoiding damage to the workpiece structure due to rigid clamping, and thus preventing any impact on the workpiece's correction effect. The connecting rod 15 can elastically rotate around the support shaft 14 under the action of the elastic rotation component 16. Under the action of the elastic rotation component 16, the two bidirectional helical shafts 3 can move along a figure-eight trajectory, thereby adaptively adjusting the clamping force according to the workpiece thickness. The greater the thickness, the greater the distance between the two bidirectional spiral shafts 3, and the greater the clamping force on the workpiece, thus adapting to the weight of the workpiece. This ensures both the stability during workpiece clamping and the stability during subsequent vertical correction of the workpiece. Each first piston 6 is fixedly connected by a connecting frame 18 and a connecting rod 15. The connecting frame 18 has an L-shaped structure and has a vertical section and a horizontal section. The vertical section is parallel to the bidirectional spiral shaft 3 and its end is vertical and fixed to the connecting rod 15. The end of the horizontal section is fixedly sleeved on the small end of the first piston 6, ensuring that the relative position between the first piston 6 and the bidirectional spiral shaft 3 remains unchanged.

[0057] In a further embodiment, the elastic rotation assembly 16 is configured to include a first support rod 1601, a second support rod 1602, and a third elastic element. A first support rod 1601 is inserted into each mounting block 2034, located below and parallel to the support shaft 14. Two second support rods 1602 are symmetrically arranged. Two connecting rods 15 on the same left side and two connecting rods 15 on the same right side share a common vertical insertion of a second support rod 1602. The two second support rods 1602 are symmetrically arranged, parallel to and below the support shaft 14. The third elastic element is a tension spring 1603, connected between the first and second support rods 1601 and 1602 located on the same left or right side.

[0058] Initially, the two bidirectional spiral shafts 3 are positioned close to each other, and under the action of the tension spring 1603, the two bidirectional spiral shafts 3 have a tendency to rotate in opposite directions around the rotation axis 402 to move closer to each other.

[0059] When pre-clamping the workpiece, the upper end of the workpiece is first placed between the clamping parts 17 of the two bidirectional spiral shafts 3. Under the push of the workpiece, the two clamping parts 17 synchronously drive the two bidirectional spiral shafts 3 to rotate in opposite directions around the rotating shaft 402 and move away from each other. The tension spring 1603 is stretched, and the tension increases, which increases the normal pressure and friction of the clamping parts 17 on the workpiece. This increases the clamping force of the two clamping parts 17 on the workpiece, thus enabling the workpiece to be clamped stably. Moreover, when the thickness of the workpiece is greater, the distance between the two bidirectional spiral shafts 3 is greater, the stretch of the tension spring 1603 is greater, and the tension is greater, which increases the normal pressure and friction of the clamping parts 17 on the workpiece. This further increases the clamping force of the two clamping parts 17 on the workpiece, thus adapting to the weight of the workpiece and ensuring stability when clamping the workpiece, as well as stability when vertically correcting the workpiece later.

[0060] After pre-clamping the workpiece, vertical alignment is performed. After vertical alignment, two connecting rods 15 on the same front or rear side are manually rotated in opposite directions around the rotating shaft 402 to move away from each other. When the tension spring 1603 passes the rotating shaft 402, the two connecting rods 15 automatically rotate in opposite directions around the rotating shaft 402 under the action of the tension spring 1603 to move away from each other. A stop block can be set on the mounting block 2034 to form a stop with the connecting rod 15, so that the connecting rod 15 can stop when it rotates to the position of the stop block, reducing the stroke of the subsequent reset process and improving the ease of operation.

[0061] In other embodiments, the clamping part 17 is configured to include a plurality of clamping blocks 1701, which are arranged along the extension direction of the bidirectional spiral shaft 3; the clamping blocks 1701 are elliptical in structure and are rotatably sleeved on the bidirectional spiral shaft 3; adjacent clamping blocks 1701 are perpendicular and fixedly connected.

[0062] Initially, the clamping blocks 1701 facing the same direction are clamped on the workpiece; when the workpiece moves downward relative to the clamping blocks 1701 due to vibration or other external factors, the workpiece synchronously drives the clamping blocks 1701 to rotate, so that all the clamping blocks 1701 are clamped on the workpiece, thereby further resisting the downward trend of the workpiece and improving the stability when clamping the workpiece.

[0063] In other embodiments, to improve the stability of the two bidirectional spiral shafts 3 sliding along a figure-eight trajectory while ensuring that the connecting rod 15 stops when it rotates to a preset position, thereby reducing the stroke of the subsequent reset process and improving operational convenience, two first sliding grooves 1011 are provided on the inner sidewalls of both crossbeams 101. The first sliding grooves 1011 on different crossbeams 101 are corresponding and symmetrically arranged, and the two first sliding grooves 1011 on the same crossbeam 101 form a figure-eight structure with the smaller opening facing upwards. The two ends of the bidirectional spiral shaft 3 are slidably inserted into the two first sliding grooves 1011 located on the same left or right side of the two crossbeams 101. With this arrangement, when the connecting rod 15 rotates around the rotation axis 402, the bidirectional spiral shaft 3 can simultaneously slide stably along the first sliding grooves 1011. When the bidirectional spiral shaft 3 moves to the lower end of the first sliding groove 1011, the connecting rod 15 stops rotating, thereby reducing the stroke of the subsequent reset process and improving operational convenience.

[0064] In other embodiments, to facilitate the rotation of the connecting rod 15, a handle 1501 is provided on the bottom side wall of each connecting rod 15. The handle 1501 has a U-shaped structure and the opening faces upward.

[0065] In other embodiments, the synchronous rotation assembly 4 is configured to include a sliding block 401. A third notch 1012 is provided in the middle of the crossbeam 101 located on the front side. At least two guide rods 1013 are inserted into the third notch 1012. The guide rods 1013 extend vertically and are spaced apart in the left-right direction. The sliding block 401 is inserted into the third notch 1012 during installation and slides onto all the guide rods 1013, thereby enabling it to slide vertically. A rotating shaft 402 is inserted through the sliding block 401. The rotating shaft 402 is parallel to the bidirectional helical shaft 3 and can... It can rotate around its own axis; a first transmission wheel 403 is fixedly sleeved on the rear end of the rotating shaft 402; a second transmission wheel 404 is fixedly sleeved on each bidirectional spiral shaft 3; an elastic ring belt 405 is sleeved on the first transmission wheel 403 and the two second transmission wheels 404 for friction transmission; a compression spring 1014 is sleeved on each guide rod 1013, and the top of the compression spring 1014 abuts against the bottom of the sliding block 401. Under the action of the compression spring 1014, the sliding block 401 has an upward tendency, so that the elastic ring belt 405 can always be tensioned when the two bidirectional spiral shafts 3 move along the figure-eight trajectory.

[0066] During use, when the workpiece is vertically straightened, the rotating shaft 402 is driven to rotate in the forward direction. The rotating shaft 402 drives the first transmission wheel 403 to rotate. The first transmission wheel 403 drives the two second transmission wheels 404 to rotate synchronously and in the same direction through the elastic ring belt 405. The second transmission wheels 404 synchronously drive the two bidirectional spiral shafts 3 to rotate synchronously and in the same direction. At the same time, through the spiral engagement between the spiral protrusion 301 and the connecting block 501, and under the restriction of the connecting frame 18, all the hydraulic cylinders 5 are driven to move inward so as to vertically straighten the workpiece through the top block 13.

[0067] After vertical alignment is completed, the rotating shaft 402 is driven to rotate in the opposite direction. The rotating shaft 402 drives the first transmission wheel 403 to rotate. The first transmission wheel 403 drives the two second transmission wheels 404 to rotate synchronously and in the same direction through the elastic ring belt 405. The second transmission wheels 404 synchronously drive the two bidirectional spiral shafts 3 to rotate synchronously and in the same direction. At the same time, through the spiral engagement between the spiral protrusion 301 and the connecting block 501, and under the restriction of the connecting frame 18, all the hydraulic cylinders 5 are driven to move outward, thereby realizing the reset of the hydraulic cylinders 5.

[0068] In other embodiments, the first transmission wheel 403 and the second transmission wheel 404 are both gear structures; the inner peripheral wall of the elastic ring belt 405 is provided with ring teeth, which mesh with both the first transmission wheel 403 and the second transmission wheel 404; thereby, the stability during transmission is further improved through the meshing of gears.

[0069] In some other embodiments, to facilitate the rotation of the rotating shaft 402, a handwheel 406 is fixedly sleeved on the front end of the rotating shaft 402.

[0070] In other embodiments, to facilitate the rotation of the rotating sleeve 202, two handrails 2021 are symmetrically arranged on the outer peripheral wall of the rotating sleeve 202. The handrails 2021 are strip-shaped and are arranged perpendicular to the rotating sleeve 202.

[0071] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. A universal tensile testing device characterized by, The universal tensile testing device comprises a rack, a clamping assembly and two bidirectional screw shafts arranged on the rack, the clamping assembly is configured to clamp and stretch a workpiece, the two bidirectional screw shafts are arranged side by side along the left-right direction and can rotate synchronously and in the same direction under the action of a synchronous rotating assembly, each bidirectional screw shaft has two helical protrusions with opposite rotation directions, each helical protrusion is helically sleeved with a hydraulic cylinder, in each hydraulic cylinder, a first piston, a second piston and a third piston are sequentially and slidably inserted from the outside to the inside, the relative position between the first piston and the bidirectional screw shaft remains unchanged, the first piston is connected with the second piston through a first elastic member, the third piston is connected with the hydraulic cylinder through a second elastic member, a first hydraulic chamber is formed between the first piston and the hydraulic cylinder, a second hydraulic chamber is formed between the second piston and the third piston, the first hydraulic chamber and the second hydraulic chamber in the same hydraulic cylinder are in communication with each other, the two first hydraulic chambers located on the same left side or the same right side in different hydraulic cylinders are in communication with each other, the third piston can block the communication between the second hydraulic chamber and the first hydraulic chamber, a top block is fixedly arranged on each third piston, the top block is located outside the hydraulic cylinder and can form a stop cooperation with the workpiece, the two top blocks located on the same front side or the same back side are initially located in the same vertical plane. The clamping assembly comprises two fixed shafts arranged along the vertical direction and capable of moving away from or close to each other, a rotating sleeve is sleeved on each fixed shaft, the rotating sleeve can rotate around its own axis, a clamping seat is threadedly sleeved on each rotating sleeve, the clamping seat forms a stop cooperation with the fixed shaft, two wedge-shaped clamping blocks are inserted into each clamping seat, the two wedge-shaped clamping blocks are simultaneously sleeved on the fixed shaft, the wedge-shaped clamping blocks and the clamping seat form a wedge face clamping structure, the wedge face clamping structure is in the shape of an eight-character, and the small mouth faces the other clamping seat, the two wedge-shaped clamping blocks are configured to clamp the workpiece. One of the clamping seats is provided with two support shafts arranged side by side along the left-right direction, two connecting rods are sleeved on the two ends of each support shaft, the two connecting rods located on the same front side or the same back side on different support shafts form an eight-character structure with the small mouth facing the other clamping seat, the connecting rods can elastically rotate around the support shaft under the action of an elastic rotating assembly, the bidirectional screw shaft is inserted into different support shafts and located on the same left side or the same right side of the two connecting rods, a clamping part is arranged on each bidirectional screw shaft, the clamping part is configured to clamp the workpiece, under the action of the elastic rotating assembly, the two bidirectional screw shafts can move along an eight-character trajectory, each first piston is fixedly connected with the connecting rod through a connecting frame.

2. The universal tensile testing device of claim 1, wherein, The elastic rotating assembly comprises a first supporting rod, a second supporting rod and a third elastic piece, two first supporting rods are arranged on the clamping seat provided with the supporting shaft, and the two first supporting rods are arranged side by side in the left-right direction; two second supporting rods are respectively connected to the two connecting rods on the same left side and the same right side of different supporting shafts, and the two second supporting rods are arranged side by side in the left-right direction; the third elastic piece is connected between the first supporting rod and the second supporting rod on the same left side or the same right side.

3. The universal tensile testing device of claim 1, wherein, The clamping part comprises a plurality of clamping blocks arranged along the extension direction of the bidirectional spiral shaft; the clamping block is an elliptical structure and is rotatably sleeved on the bidirectional spiral shaft; adjacent clamping blocks are vertically and fixedly connected.

4. The universal tensile testing device of claim 1, wherein, Four first sliding grooves are formed in the rack, the four first sliding grooves are divided into two groups, the two groups of first sliding grooves are arranged on the front and rear sides of the clamping seat, the two first sliding grooves in the same group are arranged side by side in the left-right direction and form a figure-of-eight structure with the small opening upward, and the bidirectional spiral shaft is slidingly inserted into the two first sliding grooves in different groups on the same left side or the same right side.

5. The universal tensile testing device of claim 1, wherein, A handle is arranged on each connecting rod.

6. The universal tensile testing device of claim 1, wherein, The synchronous rotating assembly comprises a sliding block, the sliding block is arranged on the rack and can elastically slide in the vertical direction; a rotating shaft is inserted into the sliding block, the rotating shaft is parallel to the bidirectional spiral shaft and can rotate around its own axis; a first transmission wheel is fixedly sleeved on the rotating shaft; a second transmission wheel is fixedly sleeved on each bidirectional spiral shaft; an elastic ring belt is commonly sleeved on the first transmission wheel and the two second transmission wheels.

7. The universal tensile testing device of claim 6, wherein, The first transmission wheel and the second transmission wheel are both gear structures; ring teeth are arranged on the inner circumferential wall of the elastic ring belt, and the ring teeth are engaged with the first transmission wheel and the second transmission wheel.

8. The universal tensile testing device of claim 6, wherein, A hand wheel is fixedly sleeved on the rotating shaft.

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