A universal testing machine for engineering material testing

Abstract

The present invention is applicable to the technical field of testing equipment, and provides a universal testing machine for engineering material testing, including: a base; a mounting table installed on the base; a lifting mechanism disposed between the mounting table and the base; a lifting table installed at the output end of the lifting mechanism; a first clamping sleeve installed on the lifting table; wherein, the first clamping sleeve includes a housing, a circular opening is provided at the bottom of the housing, a clamping component is provided inside the housing, the clamping component includes two moving plates and a driving mechanism for driving the two moving plates to approach or move away from each other; a central clamping block is installed on each moving plate, the two central clamping blocks are arranged oppositely, the two central clamping blocks are elastically slidably installed on the moving plates along the linear direction of movement of the moving plates, and a first clamping block is provided on both sides of each moving plate; and a second clamping sleeve which is disposed directly below the first clamping sleeve and has the same structure as the first clamping sleeve, and the second clamping sleeve is fixedly installed on the base.

Description

Technical Field

[0001] The present invention relates to the technical field of testing equipment, and in particular to a universal testing machine for engineering material testing. Background Art

[0002] Generally speaking, a testing machine is an instrument for verifying the quality or performance of a product or material according to design requirements before it is put into use. The testing machine is mainly used to measure the physical properties of materials or products, such as: the yield strength, tensile strength, and impact toughness of steel.

[0003] In the process of performing a tensile test with existing engineering material tensile test equipment, the two ends of a bar stock are usually clamped on the adjacent-side fixtures respectively. However, in the prior art, different specifications of fixtures are required for bar stocks with different diameters to ensure the clamping effect. Therefore, it is often necessary to replace the fixtures during the operation process, and the operation is rather troublesome. To solve this technical problem, a universal testing machine for engineering material testing is provided herein. Summary of the Invention

[0004] The purpose of the present invention is to provide a universal testing machine for engineering material testing to solve the problems raised in the above background art.

[0005] To achieve the above purpose, the present invention provides the following technical solutions:

[0006] A universal testing machine for engineering material testing, comprising: a base;

[0007] An installation table installed on the base;

[0008] A lifting mechanism arranged between the installation table and the base;

[0009] A lifting table installed at the output end of the lifting mechanism;

[0010] A first clamping sleeve installed on the lifting table; wherein, the first clamping sleeve includes a housing, a circular opening is provided at the bottom of the housing, a clamping component is arranged inside the housing, the clamping component includes two moving plates and a driving mechanism for driving the two moving plates to approach or separate from each other; a central clamping block is installed on each moving plate, the two central clamping blocks are arranged oppositely, the two central clamping blocks are elastically slidably installed on the moving plates along the linear direction of movement of the moving plates, a first clamping block is arranged on each side of the moving plate, the first clamping block is fixedly installed at one end of an installation bent rod, a third gear is fixedly installed at the other end of the installation bent rod away from the first clamping block, an installation rotating shaft is fixedly installed at the central position of the third gear, the installation rotating shaft is elastically rotatably installed on the housing, and the installation rotating shaft meshes with a rack at a position adjacent to the outer side of the central clamping block;

[0011] and a second clamping sleeve which is arranged directly below the first clamping sleeve and has the same structure as it, and the second clamping sleeve is fixedly installed on the base.

[0012] As a further solution of the present invention: The driving mechanism includes two lead screws and a rotating assembly for driving the two lead screws to rotate. Threaded holes are provided at both ends of the moving plate. The lead screws are arranged through the threaded holes at the same ends of the two moving plates, and two sections of threads with opposite helix directions are provided on the lead screws. The two ends of the lead screws are respectively rotatably installed in the installation round holes on the adjacent mounting plates inside the housing.

[0013] As a further solution of the present invention: The rotating assembly includes a rotating motor fixedly installed on the housing. The output end of the rotating motor is drivingly connected with a second gear, and a first gear is meshed on both sides of the second gear. The first gear is fixedly sleeved on the adjacent lead screw.

[0014] As a further solution of the present invention: An installation sleeve is fixedly installed on the side of the central clamping block away from the bar stock. Two racks are fixedly installed on both sides of the installation sleeve. The installation sleeve is elastically slidably installed on the installation post on the moving plate.

[0015] As a further solution of the present invention: A first elastic member is arranged inside the installation sleeve, and both ends of the first elastic member are respectively fixedly installed on the installation sleeve and the installation post.

[0016] As a further solution of the present invention: The first clamping sleeve is installed at the output end of the load limiting component, and the load limiting component is fixedly installed on the lifting platform.

[0017] As a further solution of the present invention: The load limiting component includes a cylinder body. A piston is elastically slidably arranged inside the cylinder body, and the piston divides the inside of the cylinder body into an upper chamber and a lower chamber. A connecting rod is fixedly installed at the bottom of the piston. The connecting rod passes through the through hole at the bottom of the cylinder body and is fixedly installed on the connecting rod. A unloading valve is installed on the cylinder body. A buffer sleeve is sleeved outside the cylinder body. The inside of the buffer sleeve is communicated with the lower chamber inside the cylinder body below the piston through a one-way valve. The flow direction of the one-way valve is from the buffer sleeve to the inside of the lower chamber of the cylinder body. The inside of the cylinder body is filled with a hydraulic medium during the descent of the cylinder body, and there is also part of the hydraulic medium inside the buffer sleeve.

[0018] As a further solution of the present invention: A valve core is arranged inside the unloading valve. The valve core is connected to the connecting rod through an elastic telescopic rod. The connecting rod passes through the lower end of the unloading valve and is connected to the matching column. The lower end of the connecting rod abuts against the limiting step inside the unloading valve. In this way, in the initial stage, the connecting rod is maintained at the lowermost end under the action of the elastic telescopic rod.

[0019] As a further solution of the present invention: A connection structure is arranged between the installation rotating shaft and the matching column, and the connection structure is used to adjust the height of the connecting rod according to the rotation angle of the installation rotating shaft.

[0020] As a further solution of the present invention: The connection structure includes a rotating sleeve rotatably installed at the lower end of the unloading valve and first sliding keys fixedly installed on both sides of the installation rotating shaft. The first sliding keys are slidably arranged in the guiding grooves on the side walls of both sides of the rotating sleeve, and the guiding grooves are located on the lower side of the rotating sleeve; on both side walls of the upper side inside the rotating sleeve, there is a second sliding key each, and the second sliding keys are slidably installed in the inclined sliding grooves on the outer side walls of the adjacent matching columns.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows: The two ends of the bar to be stretched and measured are respectively inserted into the first clamping sleeve and the second clamping sleeve. The outer side of the bar abuts against the four first clamping blocks, and the four first clamping blocks are distributed on the outer side of the bar. When the two moving plates approach each other, the first clamping blocks on both sides move outward simultaneously. The first clamping blocks drive the central clamping block to move outward in the direction of the bar through the installation bent rods. When the central clamping block abuts against the outer side of the bar, the clamping of the bar is completed. In this way, bars with different diameters can be clamped, ensuring the stability of clamping. It solves the problem in the prior art that when conducting tensile strength tests on bars with different diameters during the test process, it is necessary to replace the fixture. By setting the first clamping blocks and the central clamping block, multiple positions on the outer side of the bar can be clamped, making it more convenient to clamp bars of different specifications. Description of the Drawings

[0022] Figure 1 It is a schematic structural diagram of a universal testing machine for engineering material testing according to an embodiment of the present invention.

[0023] Figure 2 It is a schematic structural diagram of the first clamping sleeve in a universal testing machine for engineering material testing according to an embodiment of the present invention.

[0024] Figure 3 It is Figure 2 The enlarged view at A in

[0025] Figure 4 It is a schematic structural diagram of the central clamping block in a universal testing machine for engineering material testing according to an embodiment of the present invention.

[0026] Figure 5 It is a schematic structural diagram of the load-limiting component in a universal testing machine for engineering material testing according to an embodiment of the present invention.

[0027] Figure 6 It is Figure 5 The enlarged view at B in

[0028] Figure 7 It is a schematic structural diagram of the matching column in a universal testing machine for engineering material testing according to an embodiment of the present invention.

[0029] Figure 8Schematic diagram of the structure of a rotating sleeve in a universal testing machine for engineering material testing according to an embodiment of the present invention.

[0030] In the figure:

[0031] 100 - Base, 200 - Installation table, 300 - Lifting mechanism, 400 - Load limiting component, 500 - First clamping sleeve, 600 - Second clamping sleeve, 700 - Lifting table, 800 - Bar stock, 401 - Cylinder block, 402 - Buffer sleeve, 403 - Piston, 404 - Connecting rod, 405 - Second elastic member, 406 - Check valve, 407 - Unloading valve, 408 - Connecting rod, 409 - Valve core, 410 - Elastic telescopic rod, 411 - Matching column, 412 - Rotating sleeve, 413 - Inclined sliding groove, 414 - Second sliding key, 415 - Guide groove, 501 - Housing, 502 - Mounting plate, 503 - Moving plate, 504 - Lead screw, 505 - First gear, 506 - Second gear, 507 - Rotating motor, 508 - First clamping block, 509 - Mounting bent rod, 510 - Third gear, 511 - Mounting rotating shaft, 512 - Central clamping block, 513 - Mounting sleeve, 514 - First elastic member, 515 - First sliding key, 516 - Rack. Detailed implementation manners

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0033] Embodiment 1

[0034] Please refer to Figures 1 to 8 , a structural diagram of a universal testing machine for engineering material testing provided in Embodiment 1 of the present invention. The universal testing machine for engineering material testing includes: a base 100, an installation table 200 installed on the base 100. A lifting mechanism 300 is installed between the installation table 200 and the base 100. A lifting table 700 is installed at the output end of the lifting mechanism 300. A first clamping sleeve 500 is installed on the lifting table 700. A second clamping sleeve 600 with the same structure as the first clamping sleeve 500 is arranged directly below the first clamping sleeve 500. The second clamping sleeve 600 is fixedly installed on the base 100.

[0035] The first clamping sleeve 500 includes a housing 501. A circular opening is provided at the bottom of the housing 501. A clamping component is arranged inside the housing 501. The clamping component includes two moving plates 503 and a driving mechanism for driving the two moving plates 503 to approach or separate from each other. A central clamping block 512 is installed on each moving plate 503. The two central clamping blocks 512 are arranged oppositely and are elastically slidably installed on the moving plates 503 along the linear direction of movement of the moving plates 503. A first clamping block 508 is arranged on each side of the moving plate 503. The first clamping block 508 is fixedly installed at one end of an installation bent rod 509. A third gear 510 is fixedly installed at the end of the installation bent rod 509 away from the first clamping block 508. An installation rotating shaft 511 is fixedly installed at the central position of the third gear 510. The installation rotating shaft 511 is elastically rotatably installed on the housing 501. The installation rotating shaft 511 is engaged with a rack 516 at a position adjacent to the outer side of the central clamping block 512.

[0036] It should be noted that the first clamping block 508 and the central clamping block 512 are vertical to increase the contact area and ensure the clamping effect.

[0037] During use, the two ends of the bar stock 800 to be stretched and measured are respectively inserted into the first clamping sleeve 500 and the second clamping sleeve 600. The outer side of the bar stock 800 abuts against the four first clamping blocks 508. The four first clamping blocks 508 are distributed on the outer side of the bar stock 800. When the two moving plates 503 approach each other, the first clamping blocks 508 on both sides move outward simultaneously. The first clamping block 508 drives the central clamping block 512 to move outward in the direction of the bar stock 800 through the installation bent rod 509. When the central clamping block 512 abuts against the outer side of the bar stock 800, the clamping of the bar stock 800 is completed. In this way, bar stocks 800 with different diameters can be clamped, ensuring the stability of clamping. It solves the problem in the prior art that when performing a tensile strength test on bar stocks 800 with different diameters during the test process, the fixture needs to be replaced. By arranging the first clamping block 508 and the central clamping block 512, multiple positions on the outer side of the bar stock 800 can be clamped, making it more convenient to clamp bar stocks 800 of different specifications.

[0038] Such as Figure 2 、 Figure 3 and Figure 4As shown, in some embodiments, in order to drive the two moving plates 503 to approach or move away from each other, the driving mechanism includes two lead screws 504 and a rotating assembly for driving the two lead screws 504 to rotate. Threaded holes are provided at both ends of the moving plate 503. The lead screw 504 is arranged through the threaded holes at the same end of the two moving plates 503, and two threads with opposite helix directions are provided on the lead screw 504. The two ends of the lead screw 504 are respectively rotatably installed in the installation round holes on the adjacent mounting plates 502 inside the housing 501. In this way, when the rotating assembly rotates, the two lead screws 504 rotate simultaneously. When it is necessary to clamp the bar stock 800, the two moving plates 503 approach each other, and when it is necessary to release the clamping of the bar stock 800, the two moving plates 503 move away from each other. The two threads with opposite helix directions are respectively matched with a threaded hole.

[0039] As Figure 2 shown, in some embodiments of the present invention, the rotating assembly includes a rotating motor 507 fixedly installed on the housing 501. The output end of the rotating motor 507 is drivingly connected with a second gear 506. A first gear 505 is meshed on both sides of the second gear 506. The first gear 505 is fixedly sleeved on the adjacent lead screw 504. In this way, when the rotating motor 507 is powered on and rotates, the second gear 506 can be driven to rotate, and synchronously the second gear 506 can drive the first gears 505 on both sides to rotate synchronously.

[0040] As Figure 3 and Figure 4 shown, in some embodiments of the present invention, an installation sleeve 513 is fixedly installed on the side of the central clamping block 512 away from the bar stock 800. Two racks 516 are fixedly installed on both sides of the installation sleeve 513. The installation sleeve 513 is elastically slidably installed on the installation post on the moving plate 503. In this way, the central clamping block 512 is elastically slidably installed left and right in the housing 501.

[0041] As Figure 2 and Figure 3 shown, in some embodiments of the present invention, a first elastic member 514 is arranged inside the installation sleeve 513. The two ends of the first elastic member 514 are respectively fixedly installed on the installation sleeve 513 and the installation post. In this way, the elastic sliding installation of the central clamping block 512 is realized. By arranging the first elastic member 514, it is convenient for the central clamping block 512 to return to the initial state. The first elastic member 514 is a helical spring.

[0042] As Figure 1 and Figure 5 shown, in some embodiments of the present invention, the first clamping sleeve 500 is installed at the output end of the load limiting member 400. The load limiting member 400 is fixedly installed on the lifting platform 700. By arranging the load limiting member 400, the tensile strength measurement can be accurately realized.

[0043] As Figures 5 to 8 shown, in some embodiments of the present invention, the load-limiting component 400 includes a cylinder block 401. A piston 403 is elastically and slidably arranged inside the cylinder block 401. The piston 403 divides the interior of the cylinder block 401 into an upper chamber and a lower chamber. A connecting rod 404 is fixedly installed at the bottom of the piston 403. The connecting rod 404 passes through a through hole in the bottom of the cylinder block 401, and a housing 501 is fixedly installed on the connecting rod 404. A unloading valve 407 is installed on the cylinder block 401. A buffer sleeve 402 is sleeved outside the cylinder block 401. The interior of the buffer sleeve 402 is communicated with the lower chamber inside the cylinder block 401 below the piston 403 through a one-way valve 406. The flow direction of the one-way valve 406 is from the buffer sleeve 402 to the interior of the lower chamber of the cylinder block 401. The lower chamber of the cylinder block 401 is filled with a hydraulic medium, and there is also some hydraulic medium inside the buffer sleeve 402. During the stretching process, when the stretching measurement limit of the bar 800 is reached, the unloading valve 407 will relieve pressure and transport the medium in the lower chamber to the buffer sleeve 402, so as to protect the bar 800.

[0044] Specifically, a second elastic member 405 is further arranged inside the cylinder block 401. One end of the second elastic member 405 is fixedly installed on the piston 403, and the other end of the second elastic member 405 is fixedly installed on the top wall inside the cylinder block 401. In this way, the piston 403 is elastically and slidably installed in the cylinder block 401.

[0045] As Figures 5 to 8 shown, in some embodiments of the present invention, the rotation angle of the mounting shaft 511 is different when the diameters of the bars 800 are different. Therefore, a mounting shaft 511 on the housing 501 can be connected to the valve core of the unloading valve 407, so that the pressure relief pressure of the unloading valve 407 can be automatically adjusted according to the diameter of the bar 800. A valve core 409 is arranged inside the unloading valve 407. The valve core 409 is connected to a connecting rod 408 through an elastic telescopic rod 410. The connecting rod 408 passes through the lower end of the unloading valve 407 and is connected to a mating column 411. The lower end of the connecting rod 408 abuts against a limiting step inside the unloading valve 407. In this way, at the initial stage, the connecting rod 408 is maintained at the lowest end under the action of the elastic telescopic rod 410. When the tensile pressure received by the bar 800 reaches the set pressure, the valve core 409 overcomes the elastic force of the elastic telescopic rod 410, and the valve core 409 moves downward. The unloading valve 407 connects the lower chamber of the cylinder block 401 with the interior of the buffer sleeve 402, and unloads the pressure in the lower chamber of the cylinder block 401 to the buffer sleeve 402.

[0046] In some embodiments of the present invention, a connection structure is arranged between the mounting shaft 511 and the mating column 411. The connection structure is used to adjust the height of the connecting rod 408 according to the rotation angle of the mounting shaft 511, so that the connecting rod 408 can adjust the opening pressure of the valve core 409 in height.

[0047] In some embodiments of the present invention, the input end of the unloading valve 407 is installed on the bottom connection hole of the cylinder block 401, and the output end of the unloading valve 407 is in internal communication with the buffer sleeve 402.

[0048] As Figures 5 to 8 shown, in some embodiments of the present invention, the connection structure includes a rotating sleeve 412 rotatably installed at the lower end of the unloading valve 407 and first sliding keys 515 fixedly installed on both sides of the installation rotating shaft 511. The first sliding keys 515 are slidably arranged in the guiding grooves 415 on both side walls of the rotating sleeve 412, and the guiding grooves 415 are located at the lower side of the rotating sleeve 412; on both side walls of the upper side inside the rotating sleeve 412, a second sliding key 414 is provided on each side wall. The second sliding key 414 is slidably installed in the inclined sliding grooves 413 on the outer side wall of the adjacent mating column 411. The rotation angle of the installation rotating shaft 511 is determined according to the diameter of the bar stock 800. During the rotation of the installation rotating shaft 511, the rotating sleeve 412 is driven to rotate, and the second sliding key 414 on the rotating sleeve 412 also rotates accordingly. Under the action of the second sliding key 414, the height of the mating column 411 changes, and the rising height of the mating column 411 is proportional to the rotation angle of the installation rotating shaft 511. In this way, the unloading limit can be automatically increased according to the increase in the diameter of the bar stock 800; the mating column 411 is fixedly installed on the connecting rod 408, and the connecting rod 408 can only move upward. Due to the existence of the elastic telescopic rod 410, it cannot rotate along the center line. Therefore, when the second sliding key 414 rotates around the center line of the connecting rod 408, the connecting rod 408 and the mating column 411 will not rotate. The elastic telescopic rod 410 is a prior art and will not be described in detail here.

[0049] In some embodiments of the present invention, the rotating sleeve 412 and the mating column 411 are concentrically arranged, and the rotating sleeve 412 is rotatably sleeved on the circular step outside the unloading valve 407. The rotating sleeve 412 can be installed through a bearing.

[0050] The working principle of the present invention is:

[0051] Insert both ends of the bar 800 to be subjected to tensile measurement into the first clamping sleeve 500 and the second clamping sleeve 600 respectively. The outer side of the bar 800 abuts against the four first clamping blocks 508. The four first clamping blocks 508 are distributed on the outer side of the bar 800. When the two moving plates 503 approach each other, the first clamping blocks 508 on both sides move outward simultaneously. The first clamping blocks 508 drive the central clamping block 512 to move outward in the direction of the bar 800 through the mounting bent rod 509. When the central clamping block 512 abuts against the outer side of the bar 800, the clamping of the bar 800 is completed. In this way, bars 800 with different diameters can be clamped, ensuring the stability of clamping. During the clamping process, the mounting rotating shaft 511 rotates to drive the rotating sleeve 412 to rotate. The second sliding key 414 on the rotating sleeve 412 also rotates accordingly. Under the action of the second sliding key 414, the height of the mating column 411 changes, and the rising height of the mating column 411 is proportional to the rotation angle of the mounting rotating shaft 511. In this way, the unloading limit can be automatically increased according to the increase in the diameter of the bar 800. Then, the load-limiting component 400 is driven by the lifting mechanism 300 to move upward to conduct a tensile test on the bar 800. When the tensile measurement limit of the bar 800 is reached, the unloading valve 407 will relieve pressure and transport the medium in the lower chamber to the buffer sleeve 402, so as to protect the bar 800. When the tensile test is completed, under the action of the second elastic member 405, the piston 403 automatically returns to its initial position for the second tensile test.

[0052] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0053] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0054] In the present invention, unless otherwise clearly defined or limited, terms such as "installed", "connected", "joined", "fixed", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection, an electrical connection, or communicable with each other; it may be directly connected, or indirectly connected through an intermediate medium, and may be the internal communication of two components or the interaction relationship between two components, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0055] In the present invention, unless otherwise clearly defined or limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature is at a higher level than the second feature in terms of horizontal height. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature is at a lower level than the second feature in terms of horizontal height.

[0056] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example" or "some examples", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0057] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A universal testing machine for testing engineering materials, characterized in that: include: Base; a mounting table mounted on the base; A lifting mechanism disposed between the mounting platform and the base; A lifting platform installed at the output end of the lifting mechanism; A first clamping sleeve mounted on the lifting platform; Wherein, the first clamping sleeve comprises a shell, a circular opening is arranged at the bottom of the shell, a clamping component is arranged inside the shell, and the clamping component comprises two movable plates and a driving mechanism for driving the two movable plates to approach or move away from each other; a central clamping block is installed on each movable plate, the two central clamping blocks are arranged opposite to each other, the two central clamping blocks are elastically slidably installed on the movable plate along the linear direction of movement of the movable plate, a first clamping block is arranged on both sides of the movable plate, the first clamping block is fixedly installed on one end of the mounting bent rod, a third gear is fixedly installed on the end of the mounting bent rod away from the first clamping block, a mounting shaft is fixedly installed at the center position of the third gear, the mounting shaft is elastically rotatably installed on the shell, and the mounting shaft is meshed with a rack at an adjacent position on the outer side of the central clamping block; The first clamping sleeve is installed at the output end of the load limiting component, and the load limiting component is fixedly installed on the lifting platform; the load limiting component includes a cylinder body, and a piston is elastically and slidably arranged inside the cylinder body, and the piston divides the inner part of the cylinder body into an upper chamber and a lower chamber; a connecting rod is fixedly installed at the bottom of the piston, and the connecting rod passes through a through-hole shell at the bottom of the cylinder body and is fixedly installed on the connecting rod, and an unloading valve is installed on the cylinder body, and a buffer sleeve is provided on the outer side of the cylinder body, and the inside of the buffer sleeve is connected to the lower chamber inside the cylinder body located below the piston through a one-way valve, and the flow direction of the one-way valve is from the buffer sleeve to the inside of the lower chamber of the cylinder body, and the lower chamber of the cylinder body is filled with hydraulic medium, and there is also some hydraulic medium inside the buffer sleeve; a valve core is arranged inside the unloading valve, and the valve core is connected to the connecting rod through an elastic telescopic rod, and the connecting rod passes through the lower end of the unloading valve and is connected to the matching column, and the lower end of the connecting rod abuts against the limiting step inside the unloading valve, and in the initial stage, the connecting rod is maintained at the lowest end under the action of the elastic telescopic rod; and a second clamping sleeve which is arranged directly below the first clamping sleeve and has the same structure as the first clamping sleeve, and the second clamping sleeve is fixedly mounted on the base.

2. A universal testing machine for testing engineering materials according to claim 1, characterized in that: The driving mechanism includes two lead screws and a rotating assembly that drives the two lead screws to rotate. Threaded holes are provided at both ends of the movable plate. The lead screw is arranged to pass through the threaded holes at the same end of the two movable plates, and two sections of threads with opposite rotation directions are provided on the lead screw. The two ends of the lead screw are respectively rotatably installed in the mounting circular holes on the adjacent mounting plates inside the shell.

3. A universal testing machine for engineering material testing according to claim 2, characterized in that: The rotating assembly comprises a rotating motor fixedly mounted on the housing, the output end of the rotating motor is transmission-connected with a second gear, both sides of the second gear are meshed with a first gear, and the first gear is fixedly sleeved on an adjacent lead screw.

4. A universal testing machine for testing engineering materials according to claim 1, characterized in that: A mounting sleeve is fixedly mounted on one side of the central clamping block away from the bar material, two racks are fixedly mounted on two sides of the mounting sleeve, and the mounting sleeve is elastically slidably mounted on the mounting column of the movable plate.

5. A universal testing machine for testing engineering materials according to claim 4, characterized in that: A first elastic member is arranged inside the installation sleeve, and two ends of the first elastic member are fixedly mounted on the installation sleeve and the installation column respectively.

6. A universal testing machine for testing engineering materials according to claim 1, characterized in that: A connecting structure is provided between the installation shaft and the matching column, and the connecting structure is used to adjust the height of the connecting rod according to the rotation angle of the installation shaft.

7. A universal testing machine for testing engineering materials according to claim 6, characterized in that: The connecting structure includes a rotating sleeve rotatably installed at the lower end of the unloading valve and a first sliding key fixedly installed on both sides of the mounting shaft. The first sliding key is slidably arranged in a guide groove on the side walls of the rotating sleeve on both sides, and the guide groove is located on the lower side of the rotating sleeve; a second sliding key is arranged on both side walls on the upper side of the rotating sleeve, and the second sliding key is slidably installed in an inclined sliding groove on the outer side wall of the adjacent matching column.

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