Stud pretightening force test loading tool

Abstract

The invention relates to the technical field of stud pre-tightening force testing, and discloses a stud pre-tightening force testing loading tool which comprises a first part and a second part, a top groove is formed in the top of the first part, and a wear-resistant lining shell is installed in the top groove; the second part is arranged at the bottom of the first part, a bottom groove is formed in the bottom of the second part, a positioning sleeve is installed in the bottom groove, and a positioning hole is formed in the positioning sleeve; a third part is installed in the positioning hole, a threaded hole is formed in the top of the third part, a stud is installed at the upper end in the threaded hole, the stud penetrates through and extends to the upper end of the wear-resistant lining shell, and a nut is installed at the position, located at the upper end of the wear-resistant lining shell and the upper end of the first part, of the outer portion of the stud. Precise positioning and stable assembly of components are achieved through structure optimization, assembly is convenient and fast, the structure is reliable, the problems of positioning deviation, uneven stress and the like in testing are solved, and the pre-tightening force measurement accuracy is improved.

Description

Technical Field

[0001] This invention relates to the field of bolt preload testing technology, specifically to a bolt preload testing loading fixture. Background Technology

[0002] The stud is a key component connecting the propeller and the engine. The magnitude of its preload directly affects the reliability of the connection and the safety of use. The stud preload testing loading fixture is an important device for accurately measuring the preload under actual assembly conditions and is widely used in related mechanical assembly and testing fields.

[0003] In existing tests of bolt preload force, traditional connection methods such as bolt fastening are often used to fix components. These methods are not only cumbersome and time-consuming to assemble, but also prone to loosening after long-term use, leading to component displacement during testing and affecting the stability of preload force transmission. At the same time, the positioning structure of some testing devices is composed of multiple parts, making it difficult to ensure the coaxiality between the parts, resulting in uneven stress on the threaded connection surface of the bolt and nut when torque is applied. In addition, some devices rely on manual calibration of component positions, and the calibration accuracy is easily affected by human factors, leading to large errors in the preload force measurement results and failing to meet the requirements of accurate testing. Therefore, a loading fixture for testing bolt preload force is proposed. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a loading fixture for testing the preload of bolted piles, thereby solving the problems mentioned in the background section.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a preload testing and loading fixture for bolted piles, comprising:

[0006] The first part and the second part, wherein the top of the first part has a top groove and a wear-resistant liner is installed inside the top groove;

[0007] The second part is disposed at the bottom of the first part. The bottom of the second part has a bottom groove. A positioning sleeve is installed inside the bottom groove. A positioning hole is formed inside the positioning sleeve. The positioning hole and the positioning sleeve are integrally formed.

[0008] A third part is installed inside the positioning hole, and the third part is adapted to the positioning hole. The top of the third part has a threaded hole, and a stud is installed at the upper end of the threaded hole. The stud is connected to the threaded hole by a threaded engagement. The stud penetrates and extends to the upper end of the wear-resistant liner. A nut is installed on the outside of the stud at the upper end of the wear-resistant liner and the first part, and the nut is connected to the stud by a threaded engagement. This method enables precise positioning and stable assembly of each component, ensuring coaxiality and stress stability during torque application. The assembly operation is convenient and the overall structure is reliable. It effectively avoids component displacement or uneven stress during testing, improves the accuracy and reliability of stud preload testing, and meets the usage requirements for accurate stud preload testing under real assembly conditions.

[0009] Preferably, the wear-resistant liner has an annular positioning groove coaxially formed at the bottom of the nut, and the annular positioning groove is integrally formed with the wear-resistant liner. The inner diameter of the annular positioning groove is larger than the outer diameter of the nut. The bottom groove of the second part is precisely matched with the positioning sleeve, providing a stable installation space for the positioning sleeve and ensuring that the positioning sleeve will not be displaced during the test. The design of the positioning hole and the positioning sleeve being integrally formed completely eliminates the gaps and dimensional deviations that may be generated by the splicing structure, ensuring the coaxiality and cylindricity accuracy of the positioning hole. During the test, the third part needs to be installed in the positioning hole. The high precision of the positioning hole directly determines the installation accuracy of the third part, which in turn affects the coaxiality of the thread fit between the stud and the third part.

[0010] Preferably, the top of the first part is provided with side shells on both sides of the outer surface of the wear-resistant liner. A second return spring and a limiting wedge block are sequentially installed inside the side shell facing the wear-resistant liner. The limiting wedge block is slidably connected to the side shell. The annular positioning groove coaxially formed inside the wear-resistant liner and the bottom of the nut is integrally formed, which not only ensures the coaxiality of the annular positioning groove and the wear-resistant liner, but also improves the structural strength. The inner diameter of the annular positioning groove is larger than the outer diameter of the nut, providing sufficient installation and movement space for the nut, avoiding interference between the nut and the inner wall of the annular positioning groove during tightening, and ensuring that the torque can be smoothly applied to the threaded connection surface of the stud and the nut. The coaxial design ensures that the force center of the nut is consistent with the axis of the stud, avoiding the problem of uneven distribution of preload caused by eccentric force.

[0011] Preferably, a lever is provided on the top of the limiting wedge block, and the lever is fixedly connected to the limiting wedge block. The lever is slidably connected to the side shell. The side shells on both sides of the outer surface of the wear-resistant liner at the top of the first part provide a stable installation and movement space for the second return spring and the limiting wedge block. The second return spring and the limiting wedge block are installed sequentially inside the side shell, and the limiting wedge block is slidably connected to the side shell, forming an automatic limiting mechanism. When installing the wear-resistant liner, the lower end of the outer edge of the top of the wear-resistant liner contacts the inclined surface of the limiting wedge block, converting the axial force into a horizontal force, so that the limiting wedge block automatically retracts into the side shell. Internally, the initial positioning of the wear-resistant liner can be completed without additional operation. After the wear-resistant liner is fully inserted into the top groove, the second reset spring resets and pushes the limiting wedge block to reset, thus firmly limiting the wear-resistant liner and preventing displacement of the wear-resistant liner due to vibration or force during the test. The sliding connection design ensures the smooth movement of the limiting wedge block, reduces frictional resistance, and improves the response sensitivity of the limiting mechanism. This structure eliminates the need for bolts or other additional fasteners, simplifying the installation process of the wear-resistant liner, improving the tooling assembly efficiency, and ensuring reliable limiting effect, thus guaranteeing the stability of the tooling structure during the test.

[0012] Preferably, the top groove has top cavities on both sides, and the top cavities are integrally formed with the top groove; the lever is slidably connected to the side shell, ensuring smooth movement of the lever and avoiding jamming that affects operation; when disassembling the wear-resistant liner, only two levers need to be moved simultaneously to drive the limiting wedge block out of the limiting groove of the wear-resistant liner, releasing the fixation of the wear-resistant liner, which is simple and quick to operate without the need for additional tools; the fixture needs to be repeatedly used for pre-tightening force testing of products such as XXH propeller screw piles, and frequent installation and disassembly are the norm. This lever structure greatly reduces the difficulty of disassembling the wear-resistant liner, shortens the time for fixture maintenance and component replacement, and improves testing efficiency; at the same time, the fixed connection design ensures the connection strength between the lever and the limiting wedge block, avoiding long-term operation that may cause them to fall off or loosen, while the sliding connection reduces component wear, extends the service life of the fixture, and ensures the reliability of the fixture for long-term repeated use.

[0013] Preferably, a first return spring and a top block are installed sequentially from bottom to top inside the top cavity, and the top block is fixedly connected to the first return spring, which is fixed to the bottom of the top cavity. The top cavity and top groove on both sides of the top groove are integrally formed, ensuring the positional accuracy and structural integrity of the top cavity and top groove, and avoiding loosening or dimensional deviations that may occur in the splicing structure. The first return spring and top block installed sequentially from bottom to top inside the top cavity form an elastic pushing mechanism through a fixed connection. When disassembling the wear-resistant liner, after the push block drives the limiting wedge block to release the limit, the first return spring releases its elastic potential energy, pushing the top block upward. This design allows the wear-resistant liner to be pushed up without the need for manual prying, thus avoiding potential damage to the top groove or the wear-resistant liner during prying. The first return spring is fixed to the bottom of the top cavity, ensuring the stability of the spring installation and preventing it from shifting or falling off during extension and retraction, thus guaranteeing a stable output of the pushing force. The top block is fixedly connected to the first return spring, allowing the pushing force to be evenly transmitted to the bottom of the wear-resistant liner, preventing excessive local stress that could cause deformation of the wear-resistant liner. This structure greatly simplifies the disassembly process of the wear-resistant liner, improves operational convenience, and protects the tooling components, extending the service life of the tooling.

[0014] Preferably, the top of the second part has a guide chamfer at the upper end of the inner part of the threaded hole, and the guide chamfer is integrally formed with the second part; this ensures the dimensional and positional accuracy of the guide chamfer, improves structural strength, and avoids the problem of the chamfer falling off during subsequent processing or assembly; the design of the guide chamfer provides guidance for the installation of the stud, and when the stud is passed through the threaded hole of the second part, the chamfer can quickly guide the stud to align with the center of the threaded hole, avoiding collision or jamming between the stud and the edge of the threaded hole, reducing installation time and improving assembly efficiency; at the same time, the guide chamfer can protect the thread profile of the stud, avoiding scratching or damage between the thread and the entrance of the threaded hole during installation, ensuring the accuracy of the thread fit between the stud and the third part.

[0015] Preferably, the top of the second part has four circumferentially evenly distributed elastic locating pins at the upper end of the threaded hole, and the elastic locating pins are fixedly connected to the second part. The four elastic locating pins at the upper end of the threaded hole on the top of the second part are fixedly connected to the second part in a circumferentially evenly distributed manner, ensuring that the clamping force of the locating pins on the screw post is evenly distributed. The elastic design of the elastic locating pins allows them to adapt to screw posts of different diameters (within the adaptation range), and achieves accurate positioning of the screw post through radial clamping, avoiding radial offset or circumferential rotation of the screw post during testing. The four evenly distributed locating pins form a stable positioning structure, which has higher positioning accuracy and stronger stability compared to single or non-uniformly distributed positioning methods, and can effectively resist the torque and vibration generated during tightening. The fixed connection between the elastic locating pins and the second part ensures the installation stability of the locating pins, avoids loosening or falling off due to long-term use, and extends the service life of the tooling.

[0016] Preferably, the positioning sleeve is adapted to the bottom groove, and a magnetic ring is installed on one side of the lower end of the bottom groove, and the magnetic ring is fixedly connected to the bottom groove; the positioning sleeve is precisely adapted to the bottom groove of the second part, ensuring the fit between the positioning sleeve and the bottom groove after installation, and avoiding the shaking of the positioning sleeve caused by installation gaps; the magnetic ring fixedly connected to one side of the lower end of the bottom groove cooperates with the iron ring fixedly connected to the top of the positioning sleeve, and achieves quick fixation of the positioning sleeve through magnetic attraction; the magnetic fixation method does not require additional fasteners such as bolts and clips. During installation, the positioning sleeve only needs to be placed into the bottom groove, and the magnetic ring and iron ring will automatically attract and position, making the operation simple and quick, and greatly improving the tooling assembly efficiency; at the same time, the magnetic attraction force is moderate, which can not only ensure the stability of the positioning sleeve during the test, but also facilitate the subsequent disassembly and replacement of the positioning sleeve, meeting the installation requirements of third parts of different specifications; the fixed connection between the magnetic ring and the bottom groove, and the iron ring and the positioning sleeve, ensures the positional accuracy of both, ensures that the magnetic surfaces can be completely attached, and improves the attraction stability.

[0017] Preferably, an iron ring is provided at the top of the positioning sleeve below the magnetic ring, and the iron ring is fixedly connected to the positioning sleeve. During the installation stage, the wear-resistant liner is quickly fixed by the cooperation of the top groove and the limiting wedge block. The positioning sleeve is firmly installed by the magnetic attraction between the magnetic ring and the iron ring. The stud is accurately positioned by the guide chamfer and the elastic positioning pin. The entire installation process does not require complicated tools, and the operation is simple and efficient. During the positioning stage, the positioning structures work together to ensure the coaxiality and positional accuracy of the nut, stud, and third part, avoid component offset or rotation during the test, and ensure that the torque is accurately applied to the threaded connection surface. During the test stage, the preload is smoothly transmitted to the force transmission component through the stud. The load value of the force transmission feedback can truly reflect the magnitude of the preload under specific connection conditions and torque conditions, solving the problem of preload testing loading of the stud and meeting the core requirement of accurately measuring the preload under the actual assembly state.

[0018] Compared with the prior art, the present invention provides a loading fixture for testing the preload of bolted piles, which has the following advantages:

[0019] This invention achieves precise positioning and stable assembly of each component through a structural design that integrates a wear-resistant liner installed in the top groove, a positioning sleeve installed in the bottom groove with the positioning hole and the positioning sleeve integrally formed, and a third part adapted to the positioning hole, a threaded fit between the stud and the third part, and a threaded connection between the nut and the stud. This ensures that when torque is applied, the threaded connection surface between the stud and the nut experiences concentrated force and good coaxiality. It offers advantages such as convenient assembly, accurate positioning, and reliable structure. It solves the problems of inaccurate preload measurement due to component positioning deviation and loose assembly in stud preload testing, as well as the problems of component displacement and uneven force distribution affecting test results during testing. Attached Figure Description

[0020] Figure 1 This is a perspective view of the overall structure of the present invention;

[0021] Figure 2 This is a cross-sectional view of the overall structure of the present invention;

[0022] Figure 3 For the present invention Figure 2 Enlarged view of a portion of region A in the middle;

[0023] Figure 4 For the present invention Figure 2 Enlarged view of a portion of region B in the middle.

[0024] In the diagram: 1. First part; 2. Second part; 3. Third part; 4. Screw; 5. Nut; 6. Wear-resistant liner; 7. Annular positioning groove; 8. Top groove; 9. Top cavity; 10. First return spring; 11. Top block; 12. Side shell; 13. Second return spring; 14. Limiting wedge block; 15. Pulley block; 16. Bottom groove; 17. Positioning sleeve; 18. Positioning hole; 19. Iron ring; 20. Magnetic ring; 21. Elastic positioning pin. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] This invention provides a technical solution: a loading fixture for testing the preload of bolts. Please refer to [link / reference]. Figure 1 , Figure 2 , Figure 3 and Figure 4 ,include:

[0027] First part 1 and second part 2, the top of the first part 1 is provided with a top groove 8, and a wear-resistant liner 6 is installed inside the top groove 8;

[0028] The second part 2 is disposed at the bottom of the first part 1. The bottom of the second part 2 is provided with a bottom groove 16. A positioning sleeve 17 is installed inside the bottom groove 16. A positioning hole 18 is provided inside the positioning sleeve 17, and the positioning hole 18 and the positioning sleeve 17 are integrally formed.

[0029] In this structure, the top groove 8 on the top of the first part 1 provides a precise installation reference for the wear-resistant liner 6, and the assembly of the wear-resistant liner 6 directly matches the size design of the top groove 8. The wear-resistant liner 6 itself has high strength and wear resistance, and can directly withstand the pressure and friction during the tightening process of the nut 5, avoiding wear and deformation caused by the top groove 8 of the first part 1 directly contacting the nut 5. In the preload test of the bolt, the top groove 8 is the core installation structure, and its accuracy directly affects the positioning accuracy of the nut 5. The presence of the wear-resistant liner 6 can maintain the structural integrity and dimensional accuracy of the top groove 8 for a long time, extending the service life of the first part 1. At the same time, the detachable design of the wear-resistant liner 6 means that subsequent maintenance does not require replacing the entire first part 1, but only the worn liner needs to be replaced, reducing tooling costs.

[0030] The wear-resistant liner 6 has an annular positioning groove 7 coaxially formed at the bottom of the nut 5, and the annular positioning groove 7 is integrally formed with the wear-resistant liner 6. The inner diameter of the annular positioning groove 7 is larger than the outer diameter of the nut 5. The bottom groove 16 of the second part 2 is precisely matched with the positioning sleeve 17, providing a stable installation space for the positioning sleeve 17 and ensuring that the positioning sleeve 17 will not be displaced during the test. The design of the positioning hole 18 being integrally formed with the positioning sleeve 17 completely eliminates the gaps and dimensional deviations that may be generated by the splicing structure, and ensures the coaxiality and cylindricity accuracy of the positioning hole 18. During the test, the third part 3 needs to be installed in the positioning hole 18. The high precision of the positioning hole 18 directly determines the installation accuracy of the third part 3, which in turn affects the coaxiality of the threaded fit between the stud 4 and the third part 3.

[0031] The top of the first part 1 is provided with side shells 12 on both sides of the outer surface of the wear-resistant liner 6. The second return spring 13 and the limiting wedge block 14 are installed sequentially on the side of the side shell 12 facing the wear-resistant liner 6. The limiting wedge block 14 is slidably connected to the side shell 12. The annular positioning groove 7 is opened coaxially with the bottom of the nut 5 inside the wear-resistant liner 6. It adopts an integral molding process, which not only ensures the coaxiality of the annular positioning groove 7 and the wear-resistant liner 6, but also improves the structural strength. The inner diameter of the annular positioning groove 7 is larger than the outer diameter of the nut 5, which provides sufficient installation and movement space for the nut 5 and avoids interference between the nut 5 and the inner wall of the annular positioning groove 7 during the tightening process. It ensures that the torque can be smoothly applied to the threaded connection surface of the stud 4 and the nut 5. The coaxial design makes the force center of the nut 5 consistent with the axis of the stud 4, avoiding the problem of uneven distribution of preload caused by eccentric force.

[0032] A lever 15 is provided on the top of the limiting wedge block 14, and the lever 15 is fixedly connected to the limiting wedge block 14. The lever 15 is slidably connected to the side shell 12. The side shells 12 on both sides of the outer surface of the wear-resistant liner 6 on the top of the first part 1 provide a stable installation and movement space for the second return spring 13 and the limiting wedge block 14. The second return spring 13 and the limiting wedge block 14 are installed sequentially inside the side shell 12, and the limiting wedge block 14 is slidably connected to the side shell 12, forming an automatic limiting mechanism. When installing the wear-resistant liner 6, the lower end of the outer edge of the top of the wear-resistant liner 6 contacts the inclined surface of the limiting wedge block 14, converting the axial force into a horizontal force, so that the limiting wedge block 14... 4. The wear-resistant liner 6 is automatically retracted into the side shell 12, completing the initial positioning of the wear-resistant liner 6 without additional operation. After the wear-resistant liner 6 is fully inserted into the top groove 8, the second return spring 13 resets and pushes the limiting wedge block 14 to reset, providing a stable limit for the wear-resistant liner 6 and preventing displacement of the wear-resistant liner 6 due to vibration or force during the test. The sliding connection design ensures the smooth movement of the limiting wedge block 14, reduces frictional resistance, and improves the response sensitivity of the limiting mechanism. This structure eliminates the need for additional fasteners such as bolts, simplifying the installation process of the wear-resistant liner 6, improving the tooling assembly efficiency, and ensuring reliable limiting effect, thus guaranteeing the stability of the tooling structure during the test.

[0033] Top cavities 9 are formed on both sides of the top groove 8, and the top cavities 9 are integrally formed with the top groove 8; the lever 15 on the top of the limiting wedge block 14 is fixedly connected to the limiting wedge block 14, ensuring that the operating lever 15 can directly drive the limiting wedge block 14 to move, with no loss in force transmission and precise operation response; the lever 15 is slidably connected to the side shell 12, ensuring the smooth movement of the lever 15 and avoiding jamming that affects operation; when disassembling the wear-resistant liner 6, only two levers 15 need to be moved simultaneously to drive the limiting wedge block 14 out of the limiting groove of the wear-resistant liner 6, releasing the wear-resistant liner 6. The fixture is fixed, easy and quick to operate, and requires no additional tools. Since the fixture is frequently used for pre-tightening force testing of products such as the XX10H propeller screw pile 4, frequent installation and disassembly are common. The structure of the lever 15 significantly reduces the difficulty of disassembling the wear-resistant liner 6, shortens the time for fixture maintenance and component replacement, and improves testing efficiency. At the same time, the fixed connection design ensures the connection strength between the lever 15 and the limiting wedge block 14, preventing them from falling off or loosening due to long-term operation. The sliding connection reduces component wear, extends the service life of the fixture, and ensures the reliability of the fixture for long-term repeated use.

[0034] Inside the top cavity 9, a first return spring 10 and a top block 11 are installed sequentially from bottom to top, with the top block 11 fixedly connected to the first return spring 10. The first return spring 10 is fixed to the bottom of the top cavity 9. The top cavities 9 and top grooves 8 on both sides of the top groove 8 are integrally formed, ensuring the positional accuracy and structural integrity of the top cavities 9 and top grooves 8, and avoiding loosening or dimensional deviations that may occur in the splicing structure. The first return spring 10 and top block 11 installed sequentially from bottom to top inside the top cavity 9 form an elastic pushing mechanism through a fixed connection. When the wear-resistant liner 6 is disassembled, after the push block 15 drives the limiting wedge block 14 to release the limit, the first return spring 10 releases its elastic potential energy, pushing the top block 11. The upward movement of the top block 11 pushes the wear-resistant liner 6 to rise, eliminating the need for manual prying and avoiding potential damage to the top groove 8 or the wear-resistant liner 6 during prying. The first return spring 10 is fixed to the bottom of the top cavity 9, ensuring the stability of the spring installation and preventing it from shifting or falling off during extension and retraction, thus ensuring a stable output of the pushing force. The top block 11 is fixedly connected to the first return spring 10, allowing the pushing force to be evenly transmitted to the bottom of the wear-resistant liner 6, preventing excessive local stress that could cause deformation of the wear-resistant liner 6. This structure greatly simplifies the disassembly process of the wear-resistant liner 6, improves operational convenience, and protects the tooling components, extending the service life of the tooling.

[0035] The top of the second part 2 has a guide chamfer at the upper end of the threaded hole, and the guide chamfer is integrally formed with the second part 2. The guide chamfer at the upper end of the threaded hole at the top of the second part 2 is integrally formed with the second part 2, which not only ensures the dimensional and positional accuracy of the guide chamfer, but also improves the structural strength and avoids the problem of the chamfer falling off during subsequent processing or assembly. The design of the guide chamfer provides guidance for the installation of the stud 4. When the stud 4 is passed through the threaded hole of the second part 2, the chamfer can quickly guide the stud 4 to align with the center of the threaded hole, avoiding collision or jamming between the stud 4 and the edge of the threaded hole, reducing installation time and improving assembly efficiency. At the same time, the guide chamfer can protect the thread profile of the stud 4, avoiding scratching or damage between the thread and the threaded hole entrance during installation, ensuring the accuracy of the thread fit between the stud 4 and the third part 3.

[0036] The top of the second part 2 has four circumferentially evenly distributed elastic locating pins 21 at the upper end of the threaded hole, and the elastic locating pins 21 are fixedly connected to the second part 2. The four elastic locating pins 21 at the upper end of the threaded hole of the second part 2 are fixedly connected to the second part 2 in a circumferentially evenly distributed manner, ensuring that the clamping force of the locating pins on the screw post 4 is evenly distributed. The elastic design of the elastic locating pins 21 allows them to adapt to screw posts 4 of different diameters (within the adaptation range), and achieves accurate positioning of the screw post 4 through radial clamping action, avoiding radial offset or circumferential rotation of the screw post 4 during testing. The four evenly distributed locating pins form a stable positioning structure, which has higher positioning accuracy and stronger stability compared to single or non-uniformly distributed positioning methods, and can effectively resist the torque and vibration generated during tightening. The fixed connection between the elastic locating pins 21 and the second part 2 ensures the installation stability of the locating pins, avoids loosening or falling off due to long-term use, and extends the service life of the tooling.

[0037] The positioning sleeve 17 is adapted to the bottom groove 16. A magnetic ring 20 is installed on one side of the lower end of the bottom groove 16, and the magnetic ring 20 is fixedly connected to the bottom groove 16. The positioning sleeve 17 is precisely adapted to the bottom groove 16 at the bottom of the second part 2, ensuring the fit between the positioning sleeve 17 and the bottom groove 16 after installation, and avoiding the shaking of the positioning sleeve 17 caused by installation gaps. The magnetic ring 20 fixedly connected to one side of the lower end of the bottom groove 16 cooperates with the iron ring 19 fixedly connected to the top of the positioning sleeve 17, and the positioning sleeve 17 is quickly fixed through magnetic attraction. The magnetic fixation method does not require bolts or buckles. With additional fasteners, during installation, simply place the positioning sleeve 17 into the bottom groove 16, and the magnetic ring 20 and iron ring 19 will automatically adhere and position themselves. This is simple and quick to operate, greatly improving the efficiency of tooling assembly. At the same time, the magnetic attraction force is moderate, which not only ensures the stability of the positioning sleeve 17 during testing, but also facilitates the subsequent disassembly and replacement of the positioning sleeve 17, meeting the installation requirements of different specifications of the third part 3. The fixed connection between the magnetic ring 20 and the bottom groove 16, and between the iron ring 19 and the positioning sleeve 17, ensures the positional accuracy of both, ensures that the magnetic surfaces can fully fit together, and improves the adsorption stability.

[0038] The top of the positioning sleeve 17 is located at the lower end of the magnetic ring 20, and an iron ring 19 is fixedly connected to the positioning sleeve 17. During installation, the wear-resistant liner 6 is quickly fixed by the cooperation of the top groove 8 and the limiting wedge block 14. The positioning sleeve 17 is securely installed by the magnetic attraction between the magnetic ring 20 and the iron ring 19. The screw post 4 is accurately positioned by the guide chamfer and the elastic positioning pin 21. The entire installation process does not require complicated tools, and the operation is simple and efficient. During the positioning stage, the positioning structures work together to ensure the coaxiality and positional accuracy of the nut 5, the screw post 4, and the third part 3, avoiding the need for testing. The offset or rotation of the components ensures that the torque is accurately applied to the threaded connection surface. During the testing phase, the preload is smoothly transmitted to the force transmission component through the stud 4. The load value of the force transmission feedback can truly reflect the magnitude of the preload under specific connection and torque conditions, solving the problem of loading the stud preload test and meeting the core requirement of accurately measuring the preload under actual assembly conditions. During the disassembly phase, the wear-resistant liner 6 is released by the lever 15, the first return spring 10 lifts the wear-resistant liner 6, and the positioning sleeve 17 can be directly released from the magnetic fixation. The entire disassembly process is quick and easy and will not damage the tooling components.

[0039] This solution: When installing the wear-resistant liner 6, the wear-resistant liner 6 is directly inserted downward into the top groove 8. The lower end of the outer edge of the top of the wear-resistant liner 6 contacts the inclined surface of the limiting wedge block 14, converting the force into a horizontal force, thereby causing the limiting wedge block 14 to retract into the side shell 12. The second return spring 13 is compressed and deformed under force. When the wear-resistant liner 6 is completely inserted into the top groove 8, the second return spring 13 pushes the limiting wedge block 14 to reset, thereby limiting and fixing the wear-resistant liner 6. When disassembling the wear-resistant liner 6, the two levers 15 are simultaneously moved to disengage the limiting wedge block 14 from the wear-resistant liner 6. The first return spring 10 pushes the top block 11, thereby pushing the wear-resistant liner 6 to rise, so as to facilitate the disassembly of the wear-resistant liner 6.

[0040] The first part 1 and the second part 2 are two perforated square metal plates, which are welded and fixed to a specific bracket. The third part 3 is inserted into the positioning hole 18 of the positioning sleeve 17. The magnetic ring 20 in the bottom groove 16 of the second part 2 and the iron ring 19 on the top of the positioning sleeve 17 are magnetically attracted to the positioning sleeve 17 and the bottom groove 16. Then the screw 4 is passed through the guide chamfer of the second part 2 and threaded into the threaded hole of the third part 3. The four elastic positioning pins 21 will radially clamp the screw 4 to achieve precise positioning.

[0041] A specific torque is applied to the nut 5 by an external device. During the tightening process, the cooperation between the third part 3 and the positioning hole 18, as well as the elastic positioning pin 21, restricts the rotation of the stud 4, ensuring that the torque is accurately applied to the threaded connection surface. The preload is transmitted through the stud 4 to the force transmission component connected below the third part 3. The preload under specific conditions can be obtained by reading the load value of the force transmission feedback. After the test is completed, the limit is released by moving the lever 15, and the nut 5 and stud 4 are disassembled. This tooling can be repeatedly used for preload testing of products such as the XX10H propeller stud 4.

[0042] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0043] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A loading fixture for testing the preload of bolted piles, characterized in that, include: The first part (1) and the second part (2) are provided with a top groove (8) on the top of the first part (1), and a wear-resistant liner (6) is installed inside the top groove (8). The second part (2) is disposed at the bottom of the first part (1). The bottom of the second part (2) is provided with a bottom groove (16). A positioning sleeve (17) is installed inside the bottom groove (16). A positioning hole (18) is provided inside the positioning sleeve (17), and the positioning hole (18) and the positioning sleeve (17) are integrally formed. The third part (3) is installed inside the positioning hole (18), and the third part (3) is adapted to the positioning hole (18). The top of the third part (3) is provided with a threaded hole. A stud (4) is installed at the upper end of the threaded hole, and the stud (4) is connected to the threaded hole by a threaded engagement. The stud (4) penetrates and extends to the upper end of the wear-resistant liner (6). A nut (5) is installed on the outside of the stud (4) at the upper end of the wear-resistant liner (6) and the first part (1), and the nut (5) is connected to the stud (4) by a threaded engagement.

2. The test loading tool for testing the pre-tightening force of a screw pile according to claim 1, characterized in that: The wear-resistant liner (6) has an annular positioning groove (7) coaxially formed with the bottom of the nut (5) inside, and the annular positioning groove (7) is integrally formed with the wear-resistant liner (6). The inner diameter of the annular positioning groove (7) is larger than the outer diameter of the nut (5).

3. The test loading tool for testing the pre-tightening force of a screw pile according to claim 1, characterized in that: The top of the first part (1) is provided with side shells (12) on both sides of the outer side of the wear-resistant liner (6). The second return spring (13) and the limiting wedge block (14) are installed in sequence on the side of the side shell (12) facing the wear-resistant liner (6). The limiting wedge block (14) is slidably connected to the side shell (12).

4. The test loading tool for testing the pre-tightening force of a screw pile according to claim 3, characterized in that: The top of the limiting wedge block (14) is provided with a lever block (15), and the lever block (15) is fixedly connected to the limiting wedge block (14). The lever block (15) is slidably connected to the side shell (12).

5. The test loading tool for testing the pre-tightening force of a screw pile according to claim 1, characterized in that: The top groove (8) has a top cavity (9) on both sides inside, and the top cavity (9) and the top groove (8) are integrally formed.

6. The test loading tool for testing the pre-tightening force of a screw pile according to claim 5, characterized in that: The top cavity (9) is equipped with a first reset spring (10) and a top block (11) from bottom to top, and the top block (11) is fixedly connected to the first reset spring (10). The first reset spring (10) is fixed to the bottom of the top cavity (9).

7. The test loading tool for testing the pre-tightening force of a screw pile according to claim 1, characterized in that: The top of the second part (2) is provided with a guide chamfer at the upper end of the inside of the threaded hole, and the guide chamfer is integrally formed with the second part (2).

8. The test loading tool for testing the pre-tightening force of a screw pile according to claim 1, characterized in that: The top of the second part (2) is provided with four elastic positioning pins (21) evenly distributed in the circumferential direction at the upper end of the threaded hole, and the elastic positioning pins (21) are fixedly connected to the second part (2).

9. The test loading tool for testing the pre-tightening force of a screw pile according to claim 1, characterized in that: The positioning sleeve (17) is adapted to the bottom groove (16), and a magnetic ring (20) is installed on one side of the lower end of the bottom groove (16), and the magnetic ring (20) is fixedly connected to the bottom groove (16).

10. The preload testing and loading fixture for bolted piles according to claim 9, characterized in that: The top of the positioning sleeve (17) is provided with an iron ring (19) at the lower end of the magnetic ring (20), and the iron ring (19) is fixedly connected to the positioning sleeve (17).

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