A pre-tightening mechanical joint of a snap ring snap connection, a precast concrete pile and a connecting method

Abstract

The application discloses a clamping ring clamped pre-tightening mechanical joint, a precast concrete pile and a connecting method, wherein the joint comprises a plug rod with a plug, a large nut with a containing cavity, a pre-tightening nut with a pre-tightening nut threaded connection part and a pre-tightening nut driving part, a clamping ring arranged in the pre-tightening nut, and when the clamping ring is clamped on the plug, the driving part can drive the pre-tightening nut driving part from the side of the pre-tightening nut, so that the pre-tightening nut rotates and moves in the axial direction of the large nut, thereby locking the plug and the pre-tightening nut in the axial direction of the large nut. The clamping ring clamped pre-tightening mechanical joint has the following beneficial effects: the clamping ring clamped pre-tightening mechanical joint can effectively eliminate the axial gap among the plug, the clamping ring and the pre-tightening nut, so that the precast concrete pile connection part will not crack and generate cracks when subjected to the action of pulling force, shearing force or bending force.

Description

Technical Field

[0001] This invention relates to the field of precast component technology, and in particular to a pre-tightening mechanical joint with snap ring connection, a precast concrete pile and connection method. Background Technology

[0002] Most engineering piles (precast piles) are multi-section piles, and the ends of existing precast concrete piles are generally connected quickly between piles using mechanical joints.

[0003] Article 5.1.7 of the "Technical Standard for Prestressed Concrete Pipe Piles" (JGJ / T406-2017) stipulates that for prestressed pipe piles that are strictly required to be free of cracks, the crack control level should be Level I. Article 5.1.8 stipulates that when the pipe pile is under axial tension, the crack control level is Level I; when the pipe pile is under bending, the crack control level is Level II for pipe piles in weakly corrosive environments and above, and Level I for pipe piles in moderately and strongly corrosive environments and above.

[0004] Article 3.4.4 of the "Code for Design of Concrete Structures" (GB50010-2015) stipulates that the stress crack control level of the cross-section of structural members is divided into three levels, and the classification and requirements shall comply with the following provisions:

[0005] Level 1 – For components that are strictly required to be free of cracks, when calculated according to the standard load combination, the concrete at the tension edge of the component should not generate tensile stress.

[0006] Level 2 – For components that are generally required to be free of cracks, when calculated according to the standard load combination, the tensile stress in the concrete at the tension edge of the component should not exceed the standard value of the tensile strength of the concrete.

[0007] Level 3 – Components Allowed to Crack: For reinforced concrete components, when calculating based on the quasi-permanent load combination and considering the long-term effects, the maximum crack width of the component should not exceed the maximum crack width limit specified in Table 3.4.5 of this code. For prestressed concrete components, when calculating based on the standard load combination and considering the long-term effects, the maximum crack width of the component should not exceed the maximum crack width limit specified in Clause 3.4.5 of this code; for prestressed concrete components in Class 2a environments, calculations should also be performed based on the quasi-permanent load combination, and the tensile stress in the concrete at the tension edge of the component should not exceed the standard value of the tensile strength of the concrete. Clause 3.4.5 of this code specifies that the crack control level for prestressed concrete structures is Level 1 in Class 3a and 3b environments, and Level 2 in Class 2b environments. Cracks are not allowed in either Level 1 or Level 2 crack control levels. In Class 2a environments, the crack control level is Level 3, with a maximum crack width limit of 0.1 mm. In Class 1 environments, the crack control level is Level 3, with a maximum crack width limit of 0.2 mm.

[0008] like Figure 23 The diagram shows the first structural form of an existing mechanical joint, including a large nut 2, a small nut 21, a plug rod 1, and a connector 90. One end of the plug rod is threaded to the small nut, and the other end has a plug. The connector is threaded to the large nut, and the end of the connector inside the large nut has multiple elastic retaining rings. The plug is inserted from one end of the connector and can abut against the elastic retaining rings to achieve the snap-fit ​​between the plug rod and the connector. This mechanical joint allows for the rapid connection of two precast concrete piles. However, this type of mechanical joint for connecting precast concrete piles has the following shortcomings: 1. When using this mechanical joint for connecting precast concrete piles, due to factors such as the inclination of the pile end face, the plug rod may over-insert into the connector. When this occurs, the precast concrete pile, under the action of tensile force, shear force, or bending force, will cause axial clearance in all or part of the mechanical joint at the pile connection end face, resulting in axial clearance at the precast concrete pile connection. This leads to cracking at the mechanical joint connection of the precast concrete pile. Specifically, for example... Figure 23 The diagram shows the insertion of the plug rod into the connector. After the plug rod is inserted into the connector, an axial gap Δh will be formed between the end of the elastic retaining ring and the stop face of the plug. As a result, when an external force is applied, a corresponding axial gap will also be generated between the connecting end faces of the precast concrete pile. This makes it impossible to meet the requirements of Article 5.1.7 of the "Technical Standard for Prestressed Concrete Pipe Piles" JGJ / T406-2017, which stipulates that for prestressed pipe piles that are strictly required to be free of cracks, the crack control level should be Level 1; Article 5.1.8 stipulates that when the pipe pile body is under axial tension, the crack control level should be Level 1; when the pipe pile body is under bending... 1. The crack control level for pipe piles in weakly corrosive environments and above is Level II, while the crack control level for pipe piles in moderately and strongly corrosive environments and above is Level I; 2. Since the large nut and the connector, and the small nut and the insert rod are both connected by threads, there will be a certain axial clearance in the threaded connection. Therefore, when the mechanical joint is subjected to pull-out force, the axial clearance of the threaded connection will also cause a corresponding axial clearance between the connecting end faces of the precast concrete pile, further increasing the size of the cracks at the connection of the precast concrete pile, making it impossible to meet the crack control requirements in the "Technical Standard for Prestressed Concrete Pipe Piles" when used for precast concrete pile connections; 3. If Figure 24 As shown, when using this mechanical connector to connect precast concrete piles, there is a problem that the plug of the insert rod is not properly inserted into the connector. That is, when the insert rod is inserted into the connector, the end of the elastic retaining ring does not enter the ring groove of the insert rod. Therefore, the insert rod and the connector cannot be engaged, resulting in the failure of the pile connection.

[0009] like Figure 25The diagram shows a second structural form of an existing mechanical joint, including a large nut 2, a small nut 21, a plug rod 1, an intermediate nut 91, an elastic element 92, and retaining rings 93. One end of the plug rod is threaded to the small nut, and the other end has a plug. The intermediate nut is threaded to the large nut, and the intermediate nut has a tapered retaining surface at one end of the large nut. An elastic element and multiple retaining rings are located within the receiving cavity of the large nut. The elastic element abuts the multiple retaining rings against the tapered retaining surface of the intermediate nut. The plug is inserted from one end of the intermediate nut and compresses the elastic element, allowing the plug to pass through the space enclosed by the multiple retaining rings and be engaged between the intermediate nut and the plug, thus achieving a rapid connection between two precast concrete piles. However, using this type of mechanical joint for connecting precast concrete piles has the following drawbacks: 1. During the insertion of the plug rod into the intermediate nut, there is a situation where the central axis xx of the plug rod and the central axis yy of the intermediate nut are not aligned. Therefore, if... Figure 25 , Figure 26 and Figure 27 As shown, during the insertion of the plug rod into the middle nut, the retaining ring on the side closer to the plug rod axis contacts the plug first, while the retaining ring on the side farther from the plug rod axis contacts the plug later. The lower retaining ring contacts the plug first and compresses the spring under the action of the plug, while the upper retaining ring contacts the plug later. Therefore, the following may occur: Figure 26 The retaining ring on one side of the diagram enters between the plug and the center nut, while the retaining ring on the other side cannot enter between the plug and the center nut; or, as shown... Figure 27 The different engagement positions of the multiple retaining rings with the plug and intermediate nut can lead to pile connection failure or low connection strength of the mechanical joint. Consequently, when the precast concrete pile is subjected to tensile, shear, or bending forces, axial slippage occurs between the insert rod and the retaining ring of the mechanical joint. This can cause axial clearance in all or part of the mechanical joint at the pile connection end face, resulting in cracks at the connection point of the precast concrete pile mechanical joint. 2. When the plug is inserted into the intermediate nut and engaged with the retaining ring, a complete wedge-shaped fit is not formed between the plug, retaining ring, and intermediate nut (at the plug and retaining ring...). The force between the rings is very small. Therefore, when the insert is subjected to tensile, shear, or bending forces, the plug of the insert will squeeze the retaining ring, causing the retaining ring to slip axially relative to the plug. As a result, when using this mechanical joint to connect precast concrete piles, the precast concrete pile will experience tensile, shear, or bending forces, causing all or part of the mechanical joint at the pile connection end face to have axial clearance. This will lead to a corresponding axial clearance at the precast concrete pile connection, causing cracks to form at the mechanical joint connection of the precast concrete pile. 3. If Figure 27 As shown, since both the retaining ring and the plug have conical-cylindrical contact surfaces, and because the contact position between the retaining ring and the plug is uncertain, the contact surfaces of the retaining ring and the plug will not completely fit together when they are engaged. Figure 28As shown in the figure, curves Q1 to Q5 represent the cross-sectional radius curves at different positions of the plug's contact surface, and curve J represents the cross-sectional radius curve at a certain position of the retaining ring. As shown in the figure, when curve J is at position Q1, curve J is completely in contact with Q1. When curve J is at positions Q2 to Q5, the gap between curve J and curve Q gradually increases. In other words, when the retaining ring is at different positions of the plug, the contact state between the retaining ring and the plug is different, meaning that it cannot be guaranteed that the contact surface of the retaining ring is completely in contact with the contact surface of the plug. In other words, the contact between the retaining ring and the plug is line contact. When the mechanical joint is subjected to tensile, shear, or bending forces, axial slippage will occur between the retaining ring and the plug, or the retaining ring may partially embed into the plug (or the retaining ring may deform under force), resulting in axial clearance in the mechanical joint. That is, when using this type of mechanical joint to connect precast concrete piles, when subjected to tensile, shear, or bending forces, a corresponding axial clearance will also occur between the connecting end faces of the precast concrete piles, causing cracks to form at the mechanical joint connection of the precast concrete piles. 4. Since the large nut and the middle nut, and the small nut and the insert are all connected by threads, the threaded connection will also have a certain axial clearance. Therefore, when the mechanical joint is subjected to tensile, shear, or bending forces, the axial clearance of the threaded connection will also cause a corresponding axial clearance between the connecting end faces of the precast concrete piles, resulting in cracks to form at the mechanical joint connection of the precast concrete piles. This mechanical structure has several shortcomings, therefore, when using this mechanical joint for connecting precast concrete piles, the connection may fail to meet the requirements of Article 5.1.7 of the "Technical Standard for Prestressed Concrete Pipe Piles" (JGJ / T406-2017), which stipulates that for prestressed pipe piles with strict requirements to be free of cracks, the crack control level should be Level 1; Article 5.1.8 stipulates that when the pipe pile is under axial tension, the crack control level should be Level 1; and when the pipe pile is under bending, the crack control level should be Level 2 for pipe piles in weakly corrosive environments and above, and Level 1 for pipe piles in moderately and strongly corrosive environments and above.

[0010] Existing mechanical joints have axial clearance issues, which cause gaps to form at the joints of precast concrete piles when subjected to tensile, shear, and / or bending forces. Since precast pile foundations are underground concealed works, the precast piles themselves cannot be repaired.

[0011] Safety hazards of cracks in precast concrete pile joints in building pile foundations:

[0012] When precast concrete piles are subjected to bending and shear forces, the axial clearance of the mechanical joints at the precast concrete pile joints will cause cracks at the connection of the precast concrete piles, which will lead to the piles not being on the same axis, resulting in local eccentric stress on the connection end face of the piles; causing damage or cracking of the concrete at the pile end face, resulting in safety hazards in the building pile foundation.

[0013] When precast concrete piles are subjected to tensile forces, it is impossible to ensure that the axial gaps generated by the aforementioned mechanical joints are completely consistent. Furthermore, the design value of the axial tensile bearing capacity of the precast pile body is based on the total number of main reinforcement bars (the number of mechanical joints). As a result, the aforementioned mechanical joints will be broken one by one when subjected to tensile forces, leading to potential safety hazards in the building pile foundation.

[0014] When precast concrete piles are subjected to bending, shear, and tensile forces, axial gaps at the pile joints can lead to cracks. This can cause groundwater intrusion and corrosion of mechanical connections and / or the main reinforcement of the precast pile, making it difficult to guarantee the pile's durability. Specifically, according to Table 4.1.18 of the "Technical Specification for Building Pile Foundations" (JGJ94-2008), the annual corrosion rate of steel piles is 0.05~0.1 mm when the steel pile is above ground and in an environment without corrosive gases or corrosive volatile media. / y; When the steel pile is located below the ground and above the water level, the single-sided corrosion rate is 0.05 mm / y; when the steel pile is located below the ground and below the water level, the single-sided corrosion rate is 0.03 mm / y; when the steel pile is located below the ground and in a water level fluctuation zone, the single-sided corrosion rate is 0.1~0.3 mm / y. Therefore, it can be seen that when precast concrete piles develop cracks due to the axial gap of the mechanical joint, the mechanical joint and / or main reinforcement will be rapidly corroded, making it difficult to guarantee the durability of the precast pile. The severity of the damage is self-evident. Summary of the Invention

[0015] This invention addresses the problems caused by axial clearance in existing mechanical joint connection mechanisms, which leads to cracks at the connection of precast concrete piles, resulting in corrosion of the main reinforcement and / or mechanical joint, and local pressure on the pile end face. It proposes a pre-tightened mechanical joint with a snap ring to solve the safety hazards caused by the axial clearance after the connection of existing mechanical joints.

[0016] The technical means employed in this invention are as follows:

[0017] A pre-tightening mechanical joint with a retaining ring, comprising,

[0018] A plug rod, one end of which is a plug;

[0019] A large nut, wherein the large nut has a receiving cavity;

[0020] A preload nut has an insertion cavity inside, a retaining ring receiving groove inside the insertion cavity, and a threaded connection part and a driving part on the outer wall of the preload nut. The threaded connection part of the preload nut is located in the large nut and is threadedly connected to the receiving cavity, and at least part of the driving part of the preload nut is located outside the receiving cavity.

[0021] A retaining ring is placed in a retaining ring receiving groove. The retaining ring can open and retract within the retaining ring receiving groove. During the insertion of the plug into the insertion cavity, the plug can pass through the retaining ring and engage with the plug through the springback of the retaining ring.

[0022] When the retaining ring is engaged with the plug, the drive component can drive the preload nut drive unit from the side of the preload nut, causing the preload nut to rotate and move axially along the large nut, thereby locking the plug and the preload nut in the axial direction of the large nut.

[0023] Furthermore, the preload nut drive unit is provided with drive teeth, the drive component is a lead screw, and the lead screw is provided with engagement teeth that can mesh with the drive teeth.

[0024] Furthermore, the driving teeth are straight teeth parallel to the axis of the preload nut or helical teeth at a certain angle to the axis of the preload nut.

[0025] Furthermore, it also includes a positioning sleeve disposed in the receiving cavity for correcting the insert rod during the insertion of the insert rod into the receiving cavity.

[0026] Furthermore, the positioning sleeve is disposed between the end of the pre-tightening nut placed inside the large nut and the bottom surface of the receiving cavity. The positioning sleeve is provided with a positioning hole, the inner diameter of which is greater than or equal to the outer diameter of the plug and smaller than the inner diameter of the insertion cavity of the pre-tightening nut.

[0027] Furthermore, the inner wall of the retaining ring receiving groove near the plug insertion end of the pre-tightening nut is a first retaining surface, and the plug is provided with a second retaining surface;

[0028] When the plug is inserted into the insertion cavity of the preload nut and engages with the retaining ring, the retaining ring is located between the first engaging surface and the second engaging surface; the preload nut rotates and moves along the axial direction of the large nut, causing the first engaging surface to move toward the retaining ring and causing the first engaging surface and the second engaging surface to abut against the retaining ring respectively, so as to lock the plug and the preload nut in the axial direction of the large nut.

[0029] Furthermore, the sidewall of the retaining ring receiving groove is inclined toward the plug insertion end of the pre-tightening nut.

[0030] Furthermore, before the plug and the retaining ring are locked in the axial direction of the large nut, the threaded connection between the preload nut and the large nut is a loose-fit threaded connection.

[0031] Furthermore, after the plug and the retaining ring are locked together in the axial direction of the large nut, the tensile strength of the connection between the plug and the retaining ring is greater than or equal to the tensile strength of any one of the main rib, the large nut, and the small nut.

[0032] Furthermore, it also includes a small nut for connecting to the base of the insert rod.

[0033] A precast concrete pile includes a precast concrete pile body, main reinforcement bars, and a pre-tightening mechanical joint with snap ring connection as described in this invention.

[0034] The main reinforcement is set in the precast concrete pile body, and the large nut is provided at one end of the precast concrete pile body. The large nut is provided with the pre-tightening nut and the retaining ring.

[0035] The insertion rod is installed at the other end of the precast concrete pile body;

[0036] The end of the precast concrete pile body is provided with a drive component receiving groove;

[0037] When two adjacent precast concrete piles are connected, one end of the drive component receiving groove is connected to the outer wall of the precast concrete pile body, and the other end extends to the end of the pre-tightening nut. After the drive component is inserted into the drive component receiving groove from the outer wall of the precast concrete pile body, the drive component can interact with the pre-tightening nut drive part, causing the pre-tightening nut to rotate and move along the axial direction of the large nut, thereby locking the plug and the pre-tightening nut in the axial direction of the large nut.

[0038] Furthermore, the precast concrete pile body has a small nut at one end of the insert rod, and one end of the large nut and the small nut are respectively connected to the two ends of the main reinforcement. The insert rod is threadedly connected to the other end of the small nut.

[0039] Furthermore, after the drive component drives the preload nut to rotate and locks the plug and the preload nut in the axial direction of the large nut, the drive component remains in or is removed from the drive component receiving groove.

[0040] Furthermore, structural adhesive is injected into the connecting end face of the precast concrete pile body and the pre-tightening mechanical joint of the snap ring.

[0041] A method for connecting precast concrete piles according to the present invention includes the following steps:

[0042] The end of the precast concrete pile with the insert rod and the end of the adjacent precast concrete pile with the pre-tightening nut are moved relative to each other, and the plug of the insert rod is inserted into the insertion cavity of the pre-tightening nut to achieve the engagement of the plug and the retaining ring.

[0043] A drive component is inserted into the outer wall of the precast concrete pile, and the drive component drives the pre-tightening nut drive part, thereby causing the pre-tightening nut to rotate and move along the axial direction of the large nut, thereby locking the plug and the pre-tightening nut in the axial direction of the large nut.

[0044] Compared with the prior art, the pre-tightening mechanical connector with snap ring engagement disclosed in this invention has the following beneficial effects: The pre-tightening mechanical connector with snap ring engagement disclosed in this application has a pre-tightening nut driving part on the pre-tightening nut. After the plug is inserted into the cavity and engaged with the snap ring, the driving part can be driven from the side of the pre-tightening nut by a driving component, causing the pre-tightening nut to move axially along the large nut, thereby locking the plug and the pre-tightening nut in the axial direction of the large nut. This effectively eliminates the axial gap between the plug, snap ring, and pre-tightening nut. Furthermore, because the pre-tightening nut, insert rod, and snap ring are locked in the axial direction, during the locking process, the pre-tightening nut, insert rod, and... The retaining ring generates a certain axial force (tightening force) in the axial direction. Under the action of this axial force, the axial gaps between components such as the preload nut, insert rod, large nut, retaining ring, and small nut can be effectively eliminated. Therefore, when using the mechanical joint disclosed in this invention for precast concrete pile connection, the precast concrete pile connection will not crack under tensile, shear, or bending forces. This ensures that the mechanical joint disclosed in this invention meets the relevant requirements for crack level control in the "Technical Standard for Prestressed Concrete Pipe Piles" JGJ / T406-2017. Furthermore, it eliminates the problem of gaps generated in existing mechanical joint connections, which cause cracks at the precast concrete pile joint and pose safety hazards to the building pile foundation. Attached Figure Description

[0045] Figure 1 This is an axial view of the pre-tightened mechanical joint with snap ring engagement disclosed in this invention;

[0046] Figure 2 This is a front view of the pre-tightened mechanical joint with snap ring engagement disclosed in this invention;

[0047] Figure 3 This is a cross-sectional view of the pre-tightened mechanical joint with snap ring engagement disclosed in this invention;

[0048] Figure 4 This is a schematic diagram of the state of the pre-tightened mechanical joint with retaining ring disclosed in this invention when the plug and retaining ring are not axially locked after the plug is inserted into the pre-tightening nut.

[0049] Figure 5 This is a schematic diagram of the pre-tightened mechanical connector with retaining ring disclosed in this invention after the plug is inserted into the pre-tightening nut and the plug and retaining ring are axially locked.

[0050] Figure 6 This is a schematic diagram of the preload nut of the preload mechanical joint with snap ring engagement disclosed in this invention;

[0051] Figure 7 This is a cross-sectional view of the preload nut of the preload mechanical joint with snap ring engagement disclosed in this invention;

[0052] Figure 8 This is a top view of a first embodiment of the preload nut of the preloaded mechanical joint with snap ring engagement disclosed in this invention;

[0053] Figure 9 This is a top view of the positioning sleeve of the pre-tightened mechanical joint with snap ring engagement disclosed in this invention;

[0054] Figure 10 This is an axial view of the positioning sleeve of the pre-tightened mechanical joint with snap ring engagement disclosed in this invention;

[0055] Figure 11 This is a front view of the retaining ring of the pre-tightened mechanical joint with retaining ring engagement disclosed in this invention;

[0056] Figure 12 This is a top view of the retaining ring of the pre-tightening mechanical joint disclosed in this invention.

[0057] Figure 13 This is a front view of the drive component of the pre-tightened mechanical joint with snap ring engagement disclosed in this invention;

[0058] Figure 14 This is a right view of the drive component of the pre-tightened mechanical joint with snap ring engagement disclosed in this invention;

[0059] Figure 15 This is a front view of the large nut of the pre-tightened mechanical joint with snap ring engagement disclosed in this invention;

[0060] Figure 16 This is a cross-sectional view of the large nut of the pre-tightened mechanical joint with snap ring engagement disclosed in this invention;

[0061] Figure 17 This is a structural diagram of the insertion rod of the pre-tightened mechanical joint with snap ring engagement disclosed in this invention;

[0062] Figure 18 This is a schematic diagram of a precast concrete pile connection with a pre-tightened mechanical joint using a snap ring connection as disclosed in this invention. The number of piles in the diagram is two sections.

[0063] Figure 19A cross-sectional view of a precast concrete pile connection having a pre-tightened mechanical joint with a snap ring engagement as disclosed in this invention.

[0064] Figure 20 for Figure 19 A magnified view of a section at point D;

[0065] Figure 21 An end view of a precast concrete pile connection having a pre-tightened mechanical joint with a snap ring engagement as disclosed in this invention.

[0066] Figure 22 for Figure 21 A magnified view of a section at point F in the middle;

[0067] Figure 23 This is a structural diagram of the first type of existing mechanical connector, with the plug in an over-insertion state.

[0068] Figure 24 This is a structural diagram of the first type of existing mechanical connector, with the plug in a partially inserted state.

[0069] Figure 25 This is a structural diagram of the existing second type of mechanical connector, showing the insertion process when the axis of the insertion rod and the axis of the intermediate nut are not collinear.

[0070] Figure 26 The diagram shows the structure of the second type of mechanical connector. In the diagram, the plug of the insertion rod contacts the lower retaining ring first, preventing the lower retaining ring from entering between the plug and the middle nut.

[0071] Figure 27 This is a structural diagram of the existing second type of mechanical connector, in which multiple retaining rings are engaged at different positions between the plug and the intermediate nut;

[0072] Figure 28 This is a schematic diagram showing the contact state between the retaining ring and the plug engagement surface of the existing second type of mechanical connector.

[0073] In the diagram: 1. Insert rod; 10. Plug; 11. Insert rod connecting part; 12. Insert rod base; 13. Second snap-fit ​​surface; 2. Large nut; 20. Receiving cavity; 21. Small nut; 3. Snap ring; 4. Pre-tightening nut; 40. Insertion cavity; 41. First snap-fit ​​surface; 42. Snap ring receiving groove; 43. Plug insertion end; 45. Pre-tightening nut threaded connection part; 46. Pre-tightening nut driving part; 460. Pushing groove; 461. Driving tooth; 47. Engaging tooth part; 48. Engaging tooth connecting part; 6. Driving component; 60. Lead screw; 61. Toothed rod; 62. Driving rod; 63. Actuating rod; 7. Positioning sleeve; 70. Positioning hole; 8. Precast concrete pile; 80. Precast concrete pile body; 81. Main reinforcement; 82. Driving component receiving groove. Detailed Implementation

[0074] like Figure 1 , Figure 2 and Figure 3 The image shows a pre-tightening mechanical joint with a retaining ring, as disclosed in this invention, comprising:

[0075] Plug 1, one end of which is plug 10;

[0076] Large nut 2, wherein the large nut 2 has a receiving cavity 20;

[0077] Preload nut 4, such as Figure 6 , Figure 7 and Figure 8 As shown, the preload nut 4 has an insertion cavity 40, and the insertion cavity 40 has a retainer groove 42. The outer wall of the preload nut 4 has a preload nut threaded connection part 45 and a preload nut driving part 46. The preload nut threaded connection part 45 is located in the large nut 2 and is threadedly connected to the receiving cavity 20, and at least part of the preload nut driving part 46 is located outside the receiving cavity 20.

[0078] The retaining ring 3 is placed in the retaining ring receiving groove 42. The retaining ring 3 can open and retract within the retaining ring receiving groove 42. During the process of inserting the plug 10 into the insertion cavity 40, the plug 10 can pass through the retaining ring 3 and be engaged with the plug 10 by the springback of the retaining ring 3.

[0079] When the retaining ring 3 is engaged with the plug 10, the driving component 6 can drive the pre-tightening nut driving part 46 from the side of the pre-tightening nut 4, so that the pre-tightening nut 4 rotates and moves along the axial direction of the large nut 2, thereby locking the plug 10 and the pre-tightening nut 4 in the axial direction of the large nut 2.

[0080] The pre-tightening mechanical joint with snap ring engagement disclosed in this application has a pre-tightening nut drive part 46 on the pre-tightening nut 4, such as Figure 4 and Figure 5 As shown, the preload nut drive unit 46 can be driven from the side of the preload nut 4 by the drive component 6 after the plug 10 of the insert rod 1 is inserted into the insertion cavity 40 of the preload nut 4 and radially engaged with the retaining ring 3 placed in the receiving cavity 20. Figure 4The diagram illustrates the movement process. Specifically, after the plug is inserted into the pre-tightening nut, there is a certain axial gap L between the snap ring and the plug's engagement surface. The driving component 6 rotates under external force, causing the pre-tightening nut 4 to rotate radially (indicated by arrow B in the diagram) and move axially along the large nut 2 (indicated by arrow C in the diagram). This locks the plug 10 and the pre-tightening nut in the axial direction of the large nut 2. In other words, after the plug 10 of the insertion rod 1 engages with the snap ring 3, the pre-tightening nut 4 can move axially along the large nut 2 under the drive of the driving component 6. This axial movement of the pre-tightening nut 4 eliminates the axial gap L between the plug 10, snap ring 3, and pre-tightening nut 4. Furthermore, because the pre-tightening nut, insertion rod, and snap ring are locked in the axial direction, a torque (tightening force) is generated between the pre-tightening nut and the large nut during the locking process. This tightening force causes a certain axial force to be generated in the pre-tightening nut, insertion rod, and snap ring in the axial direction. Under the action of this axial force... The axial clearances between components such as the preload nut, insert rod, large nut, retaining ring, and small nut can be effectively eliminated. For example, the clearance between the threaded connection of the preload nut and the large nut (the axial clearance of the threaded connection in area E2 of the figure), the clearance between the insert rod base and the small nut (the axial clearance of the threaded connection in area E1 of the figure), and the clearance between the insert rod plug and the retaining ring, etc. Therefore, when using the mechanical joint disclosed in this invention for precast concrete pile connection, the precast concrete pile connection will not crack under the action of tensile force, shear force, or bending force. That is, using the mechanical joint disclosed in this invention for precast concrete pile connection can give the pile connection high tensile, bending, and shear resistance. This allows the use of the mechanical joint disclosed in this invention for precast concrete pile connection to meet the relevant requirements for crack level control in the "Technical Standard for Prestressed Concrete Pipe Piles" JGJ / T406-2017. It also eliminates the problem that gaps are generated in the connection of precast concrete piles due to the existing mechanical joint connection mechanism, which causes cracks at the joints of precast concrete piles and poses a safety hazard to the building pile foundation.

[0081] Meanwhile, since the present invention has a retaining ring receiving groove on the inner wall of the insertion cavity of the preload nut, the retaining ring can be directly installed in the retaining ring receiving groove of the preload nut, so that the two parts form an assembly, which facilitates the subsequent installation of the mechanical connector, reduces the installation difficulty, and saves costs. Furthermore, the simple structure of the retaining ring and the preload nut further reduces costs. Preferably, the end of the plug is hemispherical, parabolic, or frustum-shaped to facilitate radial expansion of the retaining ring.

[0082] Furthermore, the pre-tightening nut drive part 46 is provided with drive teeth 461, the drive component 6 is a lead screw 60, and the lead screw 60 is provided with engagement teeth 600 that can engage with the drive teeth 461.

[0083] Specifically, in this embodiment, since the preload nut drive part 46 is provided with drive teeth 461, the drive teeth 461 can be straight teeth parallel to the axis of the preload nut 4 or helical teeth at a certain angle to the axis of the preload nut. Figure 6 Since the middle tooth is a spur tooth, the drive component 6 can be a lead screw 60, such as... Figure 13 and Figure 14 As shown, the lead screw 60 is provided with engagement teeth 600 that can mesh with the drive teeth 461. At one end of the precast concrete pile, there is a drive component receiving groove 82 that communicates with the outer wall of the pile. The other end of the drive component receiving groove 82 extends to the end of the large nut 2. The lead screw 60 can be inserted between two sections of precast concrete pile through the drive component receiving groove 52, and the lead screw 60 can mesh with the engagement teeth 50 on the pre-tightening nut 4 placed in the large nut 2. The lead screw is driven to rotate at the outer wall of the precast concrete pile. The end of the lead screw 60 is provided with a hexagonal hole, a slotted groove or a cross-shaped groove, etc., so as to drive the lead screw to rotate through a tool. The rotation of the lead screw can drive the pre-tightening nut to rotate through the drive teeth on the pre-tightening nut drive part, thereby realizing the axial movement of the pre-tightening nut to lock the plug and the retaining ring in the axial direction, and eliminating the axial gap between the plug, retaining ring and pre-tightening nut of the insert rod. The preload nut is driven to rotate via a lead screw and tooth structure, which not only has a simple structure but also a large stroke, allowing the preload nut to move a large distance within a small space, ensuring locking performance. It also facilitates operation and control of the axial locking force between the insert rod and the preload nut. A spur tooth structure offers the advantage of easy machining, while a helical tooth structure allows the lead screw to apply a large circumferential driving force to the preload nut, thus facilitating its rotation and axial movement. The driving teeth can be machined directly onto the preload nut's driving section, or they can be a separate structure, where an intermediate sleeve is fitted around the preload nut's driving section, and the intermediate sleeve has driving teeth (forming a gear-like structure). The intermediate sleeve is connected to the preload nut's driving section via a key or similar structure.

[0084] Furthermore, such as Figure 3 As shown, it also includes a positioning sleeve 7 disposed in the receiving cavity 20 for correcting the insertion rod 1 during the insertion of the insertion rod 1 into the receiving cavity 20.

[0085] Specifically, by providing a positioning sleeve 7 in the receiving cavity 20 of the large nut 2 for correcting the insertion rod 1 during insertion into the receiving cavity 20, it can be ensured that the axis of the insertion rod 1 is basically coincident or basically parallel to the axis of the large nut 2. This reduces or eliminates the contact between the insertion rod 1 and the pre-tightening nut 4 in the radial direction during and / or after insertion, thus reducing the force between the insertion rod 1 and the pre-tightening nut 4. This allows the drive mechanism to drive the pre-tightening nut 4 to rotate from the side, causing the pre-tightening nut 4 to move axially along the large nut 2, thereby locking the plug 10 and the retaining ring 3 in the axial direction of the large nut 2.

[0086] Furthermore, the positioning sleeve 7 is disposed between the end of the pre-tightening nut 4 placed inside the large nut 2 and the bottom surface of the receiving cavity 20. The positioning sleeve 7 is provided with a positioning hole 70, the inner diameter of which is greater than or equal to the outer diameter of the plug 10 and smaller than the inner diameter of the insertion cavity 40 of the pre-tightening nut 4.

[0087] Specifically, in this embodiment, such as Figure 3 , Figure 9 and Figure 10 As shown, the positioning sleeve 7 has a circular structure, preferably a circular metal sheet. The outer diameter of the positioning sleeve 7 has a threaded structure, and the positioning sleeve 7 can be threaded into the receiving cavity where the large nut 2 is installed, such as... Figure 15 and Figure 16As shown, the large nut has a receiving cavity 20, and the inner wall of the receiving cavity 20 has an internal thread. One end of the large nut can be fixedly connected to the main rib, and the other end is connected to the pre-tightening nut through the internal thread. Preferably, the positioning sleeve 7 can be screwed into the root of the internal thread of the large nut. The inner diameter hole of the positioning sleeve 7 is a positioning hole 70. The inner diameter of the positioning hole 70 is greater than or equal to the maximum outer diameter of the plug 10 and smaller than the inner diameter of the insertion cavity 40 of the pre-tightening nut 4. Then, after the plug 10 of the plug rod 1 passes through the insertion cavity 40 of the pre-tightening nut 4, the plug 10 is inserted into the positioning hole 70. Since the inner diameter of the positioning hole 70 is smaller than the inner diameter of the insertion cavity 40 of the pre-tightening nut 4, the plug 10 is inserted into the positioning hole 70. The positioning hole 70 is designed to be smaller than the gap between the plug 10 (plug rod connection part) and the insertion cavity 40 of the pre-tightening nut 4. During and / or after the plug rod 1 is inserted into the pre-tightening nut 4, the positioning hole 70 limits and guides the plug rod 1, resulting in a radial gap (no contact) between the plug rod 1 and the pre-tightening nut 4. This reduces or eliminates the force between the plug rod and other components and the pre-tightening nut, allowing the driving component to drive the pre-tightening nut to rotate laterally, causing the pre-tightening nut to move axially along the large nut, thereby locking the plug and the pre-tightening nut in the axial direction of the large nut. Preferably, the positioning hole 70 of the positioning sleeve 7 is a polygonal hole, with the diameter of the inscribed circle of the polygon being greater than or equal to the maximum outer diameter of the plug 10 and smaller than the inner diameter of the insertion cavity 40 of the pre-tightening nut 4. In the figure, it is an octagonal hole. The polygonal positioning hole facilitates the insertion of tools such as an Allen wrench into the positioning hole to screw the positioning sleeve into the large nut.

[0088] The receiving cavity 20 of the large nut 2 can also be a stepped hole. The diameter of the stepped hole near the bottom surface of the receiving cavity is smaller, and the diameter of the stepped hole near the opening end is larger. An internal thread for threaded connection with the preload nut 4 is machined on the inner wall of the receiving cavity 20 of the large nut 2 near the opening end (the stepped hole with the larger diameter). A positioning sleeve mounting hole is provided at the root of the internal thread (i.e., the end of the internal thread facing the bottom surface of the receiving cavity). The diameter of the positioning sleeve mounting hole is larger than the diameter of the hole near the bottom surface of the receiving cavity and smaller than the diameter of the stepped hole near the opening end. The positioning sleeve 7 is a ring-shaped structure, preferably a ring-shaped metal sheet. The outer diameter of the positioning sleeve 7 is interference-fitted with the positioning sleeve mounting hole. The positioning sleeve 7 is inserted into the positioning sleeve mounting hole under the action of external force. The inner diameter hole of the positioning sleeve 7 is a positioning hole 70. The inner diameter of the positioning hole 70 is greater than or equal to the maximum outer diameter of the plug 10 and smaller than the preload nut 4. The inner diameter of the insertion cavity 40 of the female 4 is smaller than that of the insertion cavity 40 of the pre-tightening nut 4. After the plug 10 of the insertion rod 1 passes through the insertion cavity 40 of the pre-tightening nut 4, the plug 10 is inserted into the positioning hole 70. Since the inner diameter of the positioning hole 70 is smaller than that of the insertion cavity 40 of the pre-tightening nut 4, the gap between the positioning hole 70 and the plug 10 is smaller than the gap between the plug 10 (insertion rod connection part) and the insertion cavity 40 of the pre-tightening nut 4. During the insertion of the insertion rod 1 into the pre-tightening nut 4 and / or after the insertion rod 1 into the pre-tightening nut 4, the positioning hole 70 limits and guides the insertion rod 1, thereby making there a gap (no contact) between the insertion rod 1 and the pre-tightening nut 4 in the radial direction. That is, the force between the insertion rod and other components and the pre-tightening nut is reduced or eliminated, so that the driving component can drive the pre-tightening nut to rotate from the side, so that the pre-tightening nut moves along the axial direction of the large nut, thereby locking the plug and the retaining ring in the axial direction of the large nut.

[0089] Furthermore, such as Figure 11 and Figure 12 As shown, the retaining ring 3 is an elastic metal ring structure with one end open. The cross-section of the retaining ring can be circular, quadrilateral or rectangular, etc. The inner wall of the retaining ring receiving groove 42 near the plug insertion end 43 of the pre-tightening nut 4 is the first retaining surface 41. The plug 10 is provided with a second retaining surface 13.

[0090] When the plug 10 is inserted into the insertion cavity 40 of the pre-tightening nut 4 and engages with the retaining ring 3, the retaining ring 3 is located between the first engaging surface 41 and the second engaging surface 13; the pre-tightening nut 4 rotates and moves along the axial direction of the large nut 2, so that the first engaging surface 41 moves toward the retaining ring and the first engaging surface 41 and the second engaging surface 13 respectively abut against the two sides of the retaining ring, so as to lock the plug 10 and the pre-tightening nut in the axial direction of the large nut 2.

[0091] Furthermore, the sidewall of the retaining ring receiving groove 42 is inclined toward the plug insertion end of the pre-tightening nut 4. When the retaining ring receiving groove is inclined, the cross-section of the retaining ring is preferably a parallelogram.

[0092] Specifically, such as Figure 3 and Figure 7 As shown, the sidewall of the retaining ring receiving groove 42 is inclined towards the plug insertion end 43 of the preload nut 4. That is, the inner wall of the retaining ring receiving groove 42 is roughly truncated cone-shaped. When the plug is inserted into the retaining ring, the plug abuts against the inner hole of the retaining ring and exerts a downward (bottom of the receiving cavity) thrust on the retaining ring. The inner wall 49 of the retaining ring receiving groove will give the retaining ring a radial outward component force, making the retaining ring easier to expand. After the plug is inserted, the first snapping surface of the preload nut gives the retaining ring a radial inward component force, making the retaining ring and the plug fit tightly, forming a self-locking structure, which enhances the resistance to pull-out. The cross-section of the retaining ring is a parallelogram, which can increase the contact area between the retaining ring, the preload nut and the plug, and improve the connection strength.

[0093] Furthermore, before the plug 10 and the retaining ring 3 are locked in the axial direction of the large nut 2, the threaded connection between the preload nut 4 and the large nut 2 is a loose-fit threaded connection.

[0094] Specifically, the tolerances of the internal threads on the inner wall of the large nut's receiving cavity and the external threads on the outer wall of the preload nut can be reasonably selected as needed, so that the threaded connection between the preload nut and the large nut is a loose-fit threaded connection. Since the preload nut and the large nut are loose-fit threaded connections, the force between the preload nut and the large nut is relatively small before the plug and the retaining ring are locked, which makes it easier for the drive component to drive the preload nut to rotate from the side, so that the preload nut moves along the axial direction of the large nut, thereby locking the plug and the retaining ring in the axial direction of the large nut.

[0095] Furthermore, after the plug 10 and the retaining ring 3 are locked in the axial direction of the large nut 2, the tensile strength of the connection between the plug and the retaining ring is greater than or equal to the tensile strength of any one of the main rib, the large nut, and the small nut. Preferably, after the plug 10 and the retaining ring 3 are locked in the axial direction of the large nut 2, the plug and the retaining ring do not exhibit ductile deformation when subjected to a pull-out force of 11.7 MPa.

[0096] In this application, after the plug 10 and the retaining ring 3 are locked in the axial direction of the large nut 2, the tensile strength of the connection between the plug and the retaining ring is greater than or equal to the tensile strength of any one of the main reinforcement, the large nut, and the small nut. Furthermore, after the plug and the retaining ring are connected, there is no ductile deformation when subjected to a pull-out force of 11.7 MPa. This ensures that before the precast concrete pile with the retaining ring-connected pre-tightening mechanical joint disclosed in this invention is subjected to a pull-out force that causes ductile deformation of the main reinforcement, the large nut, small nut, insert rod, retaining ring, and pre-tightening nut will not undergo ductile deformation. Therefore, no cracks or gaps will occur between the connection end faces of the two precast piles. Before the main reinforcement becomes ductile and is pulled apart, the retaining ring-connected pre-tightening mechanical joint disclosed in this invention can reliably connect without being damaged, further guaranteeing the connection performance of the precast concrete piles connected using the retaining ring-connected pre-tightening mechanical joint disclosed in this invention. Specifically, the National Building Standard Design Atlas "Precast Concrete Square Piles" (Atlas No.: 20G361) details the relationship between pile type and prestressed main reinforcement in its table of reinforcement and mechanical properties for prestressed concrete square piles. For example, it specifies that the main prestressed reinforcement for a pile with a cross-section of 600x600 is 24Φ D 12.6; The axial compressive strength and flexural bearing capacity of prestressed concrete square piles are specified in detail, along with the design value Nt (kN) of the axial tensile bearing capacity of the pile body. The table specifies that for a B-shaped pile with a pile body of 600x600, the design value of the axial tensile bearing capacity is 2544 kN. From the above data, the design value of the tensile bearing capacity of the prestressed main reinforcement of the precast pile can be calculated as 2544 / 24=10.6 kN; 10.6x1.1=11.66≈11.7kN. That is, when the pull-out force of the pre-tightened mechanical joint with snap ring connection disclosed in this application is within 11.7 kN, there is no ductile deformation of the main reinforcement of the precast concrete pile and the pre-tightened mechanical joint with snap ring connection, and there is no slippage between the components of the mechanical joint. Therefore, no gap will be generated between the connection end faces of the precast concrete pile, thus ensuring the connection performance of the precast concrete pile.

[0097] Furthermore, it also includes a small nut 21 for connecting to the plug base 12 of the plug 1.

[0098] Specifically, in this embodiment, the insertion rod 1 is fixed to one end of the precast concrete pile by the small nut 21, and the large nut 2 is fixed to the other end of the precast concrete pile. The large nut 2 and the small nut 21 are respectively fixedly connected to the two ends of the main reinforcement in the precast concrete pile. The large nut is equipped with a positioning sleeve and a pre-tightening nut, etc., and two adjacent precast concrete piles can be quickly connected by the pre-tightening mechanical joint disclosed in this application.

[0099] Example 2

[0100] like Figure 18 , Figure 19 , Figure 20 , Figure 21 and Figure 22 The image shows a precast concrete pile disclosed in this invention, including a precast concrete pile body 80, main reinforcement 81, and a pre-tightening mechanical joint with snap ring connection according to this invention.

[0101] The main reinforcement 81 is set inside the precast concrete pile body 80. One end of the precast concrete pile body 80 is provided with the large nut 2. The large nut 2 is provided with the pre-tightening nut 4 and the retaining ring 3.

[0102] The insertion rod 1 is installed at the other end of the precast concrete pile body 80;

[0103] The end of the precast concrete pile body 80 is provided with a drive component receiving groove 82;

[0104] When two adjacent precast concrete piles are connected, one end of the drive component receiving groove 82 is connected to the outer wall of the precast concrete pile body 80, and the other end extends to the end of the pre-tightening nut 4. After the drive component 6 is inserted into the drive component receiving groove 82 from the outer wall of the precast concrete pile body 80, the drive component 6 can interact with the pre-tightening nut drive part 46, causing the pre-tightening nut 4 to rotate and move along the axial direction of the large nut 2, thereby locking the plug 10 and the pre-tightening nut 4 in the axial direction of the large nut 2.

[0105] The pre-tightening mechanical connector with snap ring engagement disclosed in this application has a pre-tightening nut drive unit. This drive unit allows the insert rod to be inserted into the insertion cavity of the pre-tightening nut and radially engaged with the snap ring placed in the receiving cavity. Then, a drive component drives the pre-tightening nut from the side, causing it to rotate and move axially along the large nut. This locks the insert rod and the pre-tightening nut in the axial direction of the large nut. In other words, after the insert rod is engaged with the snap ring, the pre-tightening nut can move axially along the large nut under the drive of the drive component. This axial movement of the pre-tightening nut eliminates the axial gap between the insert rod, snap ring, and pre-tightening nut. Furthermore, because the pre-tightening nut, insert rod, and snap ring are locked in the axial direction, a certain axial force is generated during the locking process. This axial force... Under the action of this invention, the axial gaps between components such as the pre-tightening nut, insert rod, large nut, retaining ring, and small nut can be effectively eliminated. For example, the gap between the threaded connection of the pre-tightening nut and the large nut, the gap between the threaded connection of the insert rod base and the small nut, and the gap between the insert rod plug and the retaining ring. Therefore, when using the mechanical joint disclosed in this invention for precast concrete pile connection, the precast concrete pile connection will not crack under tensile, shear, or bending forces. In other words, using the mechanical joint disclosed in this invention for precast concrete pile connection can ensure that the pile connection has high tensile, bending, and shear resistance, thus meeting the relevant requirements for crack level control in the "Technical Standard for Prestressed Concrete Pipe Piles" JGJ / T406-2017. Furthermore, it eliminates the problem of gaps generated in existing mechanical joint connection mechanisms, which can cause cracks at the precast concrete pile joint and lead to safety hazards in the building pile foundation.

[0106] Furthermore, the precast concrete pile body 80 has a small nut 21 at one end of the insert rod 1. One end of the large nut 2 and the small nut 21 are respectively connected to both ends of the main reinforcement 81, and the insert rod 1 is threadedly connected to the other end of the small nut 21. That is, the mechanical joint is set at both ends of the main reinforcement, so that the main reinforcement and the mechanical joint are coaxial, which means that the main reinforcement and the mechanical joint are on the same axis when under force, thus improving the pull-out resistance of the pile. The drive component receiving groove 82 can also be set at the end of the precast concrete pile with the small nut. When the drive component receiving groove 82 is set at the end of the precast concrete pile with the small nut, the end of the precast concrete pile with the small nut has a pre-tightening nut receiving hole, so that when the upper and lower precast piles are connected, the upper part of the pre-tightening nut is placed in the hole. One end of the drive component receiving groove 82 is connected to the precast concrete pile, and the other end is connected to the drive component receiving groove 82, so that the drive component can drive the pre-tightening nut to rotate.

[0107] Furthermore, after the drive component 6 drives the preload nut 4 to rotate and locks the plug 10 and the preload nut 4 in the axial direction of the large nut 2, the drive component 6 remains in or is removed from the drive component receiving groove 82.

[0108] Specifically, during the connection of precast concrete piles, a single lead screw can sequentially drive multiple pre-tightening nuts on the precast concrete piles to rotate, thereby axially locking all mechanical joints, eliminating axial clearance, improving the pile's pull-out resistance, and saving on operating costs. Alternatively, during the connection of precast concrete piles, each mechanical joint can be driven by a lead screw. After the lead screw drives the pre-tightening nuts to rotate and achieves axial locking, the lead screw remains in the drive component's receiving groove, meaning it is not removed from the groove. Because multiple lead screw structures are provided between two sections of precast concrete piles, the compressive strength of the precast pile ends is further improved.

[0109] Furthermore, structural adhesive is injected into the connecting end face of the precast concrete pile body 80 and the pre-tightened mechanical joint connected by the retaining ring. The structural adhesive can fill, bond and seal the connecting end face, mechanical joint and various grooves on the end face, further improving the connection performance and corrosion resistance between piles.

[0110] Example 3

[0111] A method for connecting precast concrete piles according to the present invention includes the following steps:

[0112] The end of the precast concrete pile with the insert rod and the end of the adjacent precast concrete pile with the pre-tightening nut are moved relative to each other, and the plug of the insert rod is inserted into the insertion cavity of the pre-tightening nut to achieve the engagement of the plug and the retaining ring.

[0113] A drive component is inserted into the outer wall of the precast concrete pile, and the drive component drives the pre-tightening nut drive part, thereby causing the pre-tightening nut to rotate and move along the axial direction of the large nut, thereby locking the plug and the pre-tightening nut in the axial direction of the large nut.

[0114] When the drive component (lead screw) drives the preload nut to rotate, the following two situations may occur: 1. When the force generated by the threaded connection between the preload nut and the large nut is small, that is, the connection between the preload nut and the large nut is relatively loose, during the process of the lead screw entering the receiving groove of the drive component, the lead screw and the drive teeth on the drive part of the preload nut mesh and drive the preload nut to start rotating and move axially along the large nut. When the preload nut achieves axial locking between the retaining ring and the plug, the preload nut stops rotating. At this time, the lead screw moves into the receiving groove of the drive component under the action of the drive tooth structure until the end of the lead screw abuts against the end of the receiving groove. When the lead screw is continued to be driven, the interaction between the lead screw and the drive teeth will cause the preload nut to generate a pre-tension force on the plug rod, resulting in a pre-tension force at the connection of the precast concrete pile. 1. Pressure, thus preventing buckling deformation under certain force after pile connection, improving the strength of precast concrete pile connection; 2. When the force generated by the threaded connection between the preload nut and the large nut is large, that is, the connection between the preload nut and the large nut is tight, during the process of the screw entering the drive component receiving groove, the screw meshes with the drive teeth. At this time, the drive tooth structure cannot drive the preload nut to rotate. Under the action of the tooth structure, the drive teeth move into the drive component receiving groove until the end of the screw abuts against the end of the receiving groove. Then, the screw starts to drive the preload nut to rotate through the tooth structure to achieve axial locking between the retaining ring and the plug. Thus, the axial movement of the preload nut eliminates the axial gap between the plug, retaining ring and preload nut of the insertion rod, ensuring the strength of the precast pile connection. Furthermore, since the preload nut, insert rod, and retaining ring are locked in the axial direction, a tightening force is generated between the preload nut and the large nut during the locking process. This causes a certain axial force to be generated between the preload nut, insert rod, and retaining ring in the axial direction. Under the action of this axial force, the axial gaps between the preload nut, insert rod, large nut, retaining ring, and small nut can be effectively eliminated. For example, the gap between the threaded connection of the preload nut and the large nut, the gap between the threaded connection of the insert rod base and the small nut, and the gap between the insert rod plug and the retaining ring, etc., further improve the connection performance of the mechanical joint and improve the pull-out resistance of the precast concrete pile connected by the preload mechanical joint with the retaining ring.

[0115] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A pre-tightening mechanical joint with a retaining ring, characterized in that: include, Insert rod (1), one end of which is a plug (10); Large nut (2), the large nut (2) is provided with a receiving cavity (20); A preload nut (4) is provided with an insertion cavity (40) and a retainer groove (42) in the insertion cavity (40). The outer wall of the preload nut (4) is provided with a preload nut threaded connection part (45) and a preload nut drive part (46). The preload nut threaded connection part (45) is located in the large nut (2) and is threadedly connected to the receiving cavity (20). At least part of the preload nut drive part (46) is located outside the receiving cavity (20). A retaining ring (3) is placed in the retaining ring receiving groove (42). The retaining ring (3) can open and close within the retaining ring receiving groove (42). During the process of inserting the plug (10) into the insertion cavity (40), the plug (10) can pass through the retaining ring (3) and engage with the plug (10) through the springback of the retaining ring (3). When the retaining ring (3) is engaged with the plug (10), the driving component (6) can drive the pre-tightening nut driving part (46) from the side of the pre-tightening nut (4), so that the pre-tightening nut (4) rotates and moves axially along the large nut (2), thereby locking the plug (10) and the pre-tightening nut (4) in the axial direction of the large nut (2) and eliminating the axial gap between the pre-tightening nut, the plug rod, the large nut and the retaining ring.

2. The pre-tightening mechanical joint with snap ring engagement according to claim 1, characterized in that: The preload nut drive unit (46) is provided with drive teeth (461), and the drive component (6) is a lead screw (60). The lead screw (60) is provided with engagement teeth (600) that can engage with the drive teeth (461).

3. The pre-tightened mechanical joint with retaining ring according to claim 2, characterized in that: The drive tooth (461) is a straight tooth parallel to the axis of the preload nut (4) or a helical tooth at a certain angle to the axis of the preload nut.

4. The pre-tightening mechanical joint with retaining ring according to claim 1, characterized in that: It also includes a positioning sleeve (7) disposed in the receiving cavity (20) for correcting the insert (1) during the insertion of the insert (1) into the receiving cavity (20).

5. The pre-tightened mechanical joint with retaining ring according to claim 4, characterized in that: The positioning sleeve (7) is located between the end of the pre-tightening nut (4) placed inside the large nut (2) and the bottom surface of the receiving cavity (20). The positioning sleeve (7) is provided with a positioning hole (70). The inner diameter of the positioning hole (70) is greater than or equal to the outer diameter of the plug (10) and less than the inner diameter of the insertion cavity (40) of the pre-tightening nut (4).

6. The pre-tightening mechanical joint with snap ring engagement according to claim 1, characterized in that: The inner wall of the retaining groove (42) near the plug insertion end (43) of the pre-tightening nut (4) is the first retaining surface (41), and the plug (10) is provided with a second retaining surface (13). When the plug (10) is inserted into the insertion cavity (40) of the pre-tightening nut (4) and engages with the retaining ring (3), the retaining ring (3) is located between the first engaging surface (41) and the second engaging surface (13); the pre-tightening nut (4) rotates and moves axially along the large nut (2), causing the first engaging surface (41) to move toward the retaining ring and causing the first engaging surface (41) and the second engaging surface (13) to abut against the retaining ring respectively, so as to lock the plug (10) and the pre-tightening nut in the axial direction of the large nut (2).

7. The pre-tightening mechanical joint with retaining ring according to claim 6, characterized in that: The sidewall of the retaining ring receiving groove (42) is inclined toward the plug insertion end of the pre-tightening nut (4).

8. The pre-tightening mechanical joint with retaining ring according to claim 1, characterized in that: Before the plug (10) and the retaining ring (3) are locked in the axial direction of the large nut (2), the threaded connection between the preload nut (4) and the large nut (2) is a loose fit threaded connection.

9. The pre-tightened mechanical joint with retaining ring according to claim 1, characterized in that: After the plug (10) and the retaining ring (3) are locked in the axial direction of the large nut (2), the tensile strength of the connection between the plug and the retaining ring is greater than or equal to the tensile strength of any one of the main rib, the large nut and the small nut.

10. The pre-tightening mechanical joint with retaining ring according to claim 1, characterized in that: It also includes a small nut (21) for connecting to the insert base (12) of the insert (1).

11. A precast concrete pile, characterized in that: Includes a precast concrete pile body (80), main reinforcement (81), and a pre-tightened mechanical joint with snap ring as described in any one of claims 1 to 10; The main reinforcement (81) is set inside the precast concrete pile body (80), and the precast concrete pile body (80) is provided with the large nut (2) at one end, and the large nut (2) is provided with the pre-tightening nut (4) and the retaining ring (3). The other end of the precast concrete pile body (80) is equipped with the insertion rod (1). The end of the precast concrete pile body (80) is provided with a drive component receiving groove (82). When two adjacent precast concrete piles are connected, one end of the drive component receiving groove (82) is connected to the outer wall of the precast concrete pile body (80), and the other end extends to the end of the pre-tightening nut (4). After the drive component (6) is inserted into the drive component receiving groove (82) from the outer wall of the precast concrete pile body (80), the drive component (6) can interact with the pre-tightening nut drive part (46), so that the pre-tightening nut (4) rotates and moves along the axial direction of the large nut (2), thereby locking the plug (10) and the pre-tightening nut (4) in the axial direction of the large nut (2).

12. The precast concrete pile according to claim 11, characterized in that: The precast concrete pile body (80) is provided with a small nut (21) at one end of the insert rod (1). One end of the large nut (2) and the small nut (21) are respectively connected to the two ends of the main reinforcement (81). The insert rod (1) is threadedly connected to the other end of the small nut (21).

13. The precast concrete pile according to claim 12, characterized in that: After the drive component (6) drives the preload nut (4) to rotate and locks the plug (10) and the preload nut (4) in the axial direction of the large nut (2), the drive component (6) remains in or is removed from the drive component receiving groove (82).

14. The precast concrete pile according to claim 13, characterized in that: Structural adhesive is also injected into the connecting end face of the precast concrete pile body (80) and the pre-tightening mechanical joint of the snap ring.

15. A method for connecting precast concrete piles according to any one of claims 11 to 14, characterized in that: Includes the following steps: Move the end of the precast concrete pile with the insert rod toward the end of the adjacent precast concrete pile with the pre-tightening nut, and insert the plug of the insert rod into the insertion cavity of the pre-tightening nut to achieve the engagement of the plug and the retaining ring. A drive component is inserted into the outer wall of the precast concrete pile, and the drive component drives the pre-tightening nut drive part, thereby causing the pre-tightening nut to rotate and move along the axial direction of the large nut, thereby locking the plug and the pre-tightening nut in the axial direction of the large nut.

Images