Multi-toothed card jointed pre-tightened mechanical joint, precast concrete pile and connecting method

Abstract

The application discloses a multi-tooth card jointed 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 receiving cavity, a pre-tightening nut with a pre-tightening nut threaded connection part and a pre-tightening nut driving part, a multi-tooth card assembly arranged in the pre-tightening nut, and when the multi-tooth card assembly is jointed 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 is rotated and moves axially along the large nut, thereby locking the plug and the pre-tightening nut in the axial direction of the large nut. The multi-tooth card jointed pre-tightening mechanical joint disclosed by the application can effectively eliminate the axial gap among the plug, the multi-tooth card assembly and the pre-tightening nut, so that the precast concrete pile connecting part will not crack and generate cracks when subjected to the action force such as a pulling force, a shearing force or a bending force.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of prefabricated components, in particular to a multi-tooth card clamping pre-tightening mechanical joint, a prefabricated concrete pile and a connecting method. BACKGROUND

[0002] Generally, engineering piles (prefabricated piles) are multi-section piles, and the existing prefabricated concrete pile ends are generally connected between piles by mechanical joints.

[0003] In the Technical Standard for Prestressed Concrete Pipe Pile JGJ / T406-2017, Article 5.1.7 provides that for prestressed pipe piles with strict requirements for no cracks, the crack control level should be first grade; Article 5.1.8 provides that when the pipe pile shaft is in tension, the crack control level is first grade; when the pipe pile shaft is in bending, the crack control level of the pipe pile in weak corrosion environment and above is second grade, and the crack control level of the pipe pile in medium and strong corrosion environment and above is first grade.

[0004] In the Code for Design of Concrete Structures GB50010-2015, Article 3.4.4 provides that the stress crack control level of the normal section of the structural member is divided into three grades, and the grade division and requirements should comply with the following provisions:

[0005] First grade - components with strict requirements for no cracks, when calculated according to load standard combination, the tensile edge concrete of the component should not produce tensile stress.

[0006] Second grade - components with general requirements for no cracks, when calculated according to load standard combination, the tensile stress of the tensile edge concrete of the component should not be greater than the standard value of the tensile strength of the concrete.

[0007] Third grade - components that allow cracks: for reinforced concrete components, when calculated according to load quasi-permanent combination considering the influence of long-term action, the maximum crack width of the component should not exceed the maximum crack width limit value specified in Table 3.4.5 of the present specification. For prestressed concrete components, when calculated according to load standard combination and considering the influence of long-term action, the maximum crack width of the component should not exceed the maximum crack width limit value specified in Table 3.4.5 of the present specification; for prestressed concrete components in Class 2a environment, they should also be calculated according to load quasi-permanent combination, and the tensile stress of the tensile edge concrete of the component should not be greater than the standard value of the tensile strength of the concrete. In the provisions of Table 3.4.5 of the present specification, it is specified that the crack control level of prestressed concrete structures in Class 3a and 3b environments is first grade, and the crack control level in Class 2b environment is second grade. The first and second crack control levels do not allow cracks, and the third crack control level in Class 2a environment has a maximum crack width limit of 0.1mm, and the third crack control level in Class 1 environment has a maximum crack width limit of 0.2mm.

[0008] As Figure 23 The first structure of the existing mechanical joint is shown, which includes a large nut 2, a small nut 21, a plug rod 1 and a connecting piece 90; one end of the plug rod is threadedly connected with the small nut, and the other end is provided with a plug; the connecting piece is threadedly connected with the large nut, and one end of the connecting piece arranged in the large nut is provided with a plurality of elastic clamping rings; the plug is inserted from one end of the connecting piece and can abut against the elastic clamping ring, thereby achieving clamping connection of the plug rod and the connecting piece, so that the mechanical joint can realize quick connection of two sections of precast concrete piles. However, the mechanical joint for connecting precast concrete piles has the following disadvantages: 1. When the mechanical joint is used to connect precast concrete piles, the plug rod may be over-inserted into the connecting piece due to the inclination of the pile end face and other reasons. When the plug rod is over-inserted into the connecting piece, the entire or partial mechanical joint at the connecting end face of the precast concrete pile will produce an axial gap under the action of pulling force, shearing force or bending force, thereby causing an axial gap at the connecting position of the precast concrete pile, and cracks at the connecting position of the precast concrete pile, specifically, as Figure 23 The plug of the plug rod is over-inserted into the connecting piece, and an axial gap Δh is formed between the end of the elastic clamping ring and the stop surface of the plug, so that an axial gap is also formed between the connecting end faces of the precast concrete pile under the action of external force, so that it cannot meet the requirements of the "Technical Standard for Prestressed Concrete Pipe Piles" JGJ / T406-2017, i.e., the crack control level of the prestressed pipe pile should be first level according to the provisions of Article 5.1.7; the crack control level is first level according to the provisions of Article 5.1.8 when the pipe pile body is subjected to axial tension; the crack control level is second level for the pipe pile in weak corrosion environment and above when the pipe pile body is subjected to bending; the crack control level is first level for the pipe pile in medium and strong corrosion environment and above; 2. Since the large nut and the connecting piece are connected by threads, and the small nut and the plug rod are connected by threads, there is a certain axial gap between the threads, and the axial gap of the threads will also cause an axial gap between the connecting end faces of the precast concrete pile when the mechanical joint is subjected to pulling force, thereby further increasing the size of the cracks at the connecting position of the precast concrete pile, so that it cannot meet the crack control requirements in the "Technical Standard for Prestressed Concrete Pipe Piles"; 3. As shown in Figure 24 When the mechanical joint is used to connect the precast concrete piles, the plug of the plug rod is under-inserted into the connecting piece, i.e., the end of the elastic clamping ring does not enter the ring groove of the plug rod when the plug rod is inserted into the connecting piece, so that the plug rod and the connecting piece cannot be clamped, thereby causing failure of the pile connection.

[0009] As Figure 25The second structure of the existing mechanical joint is shown, which comprises a large nut 2, a small nut 21, a plug rod 1, an intermediate nut 91, an elastic member 92 and a snap ring 93. One end of the plug rod is threadedly connected with the small nut, the other end is provided with a plug, the intermediate nut is threadedly connected with the large nut, the intermediate nut is arranged at one end of the large nut and is provided with a tapered clamping surface, the elastic member and a plurality of snap rings are arranged in the accommodating cavity of the large nut, the elastic member abuts the plurality of snap rings on the tapered clamping surface of the intermediate nut, the plug is inserted into one end of the intermediate nut and can compress the elastic member, so that the plug passes through the space surrounded by the plurality of snap rings and is clamped between the intermediate nut and the plug to realize the quick connection of two sections of precast concrete piles. However, the following problems exist in the connection of the precast concrete piles by using the mechanical joint: 1. During the process of inserting the plug rod into the intermediate nut, the central axis x-x of the plug rod is not coaxial with the central axis y-y of the intermediate nut, so that, as shown in Figure 25 、 Figure 26 and Figure 27 , during the process of inserting the plug rod into the intermediate nut, the snap ring on the side close to the axis of the plug rod first contacts the plug, the snap ring on the side far from the axis of the plug rod contacts the plug later, the lower snap ring first contacts the plug and is compressed under the action of the plug, and the upper snap ring contacts the plug later. Therefore, as shown in Figure 26 , the snap ring on one side enters between the plug and the intermediate nut, and the snap ring on the other side cannot enter between the plug and the intermediate nut. Or, as shown in Figure 27 , the positions of the plurality of snap rings clamped with the plug and the intermediate nut are different, which causes the failure of pile connection or low connection strength of the mechanical joint, so that axial slip occurs between the plug rod and the snap ring of the mechanical joint when the precast concrete pile is subjected to pulling force, shearing force or bending force, and thus axial gap is generated at the whole or part of the mechanical joint at the pile connection end face, which causes cracks at the mechanical joint connection of the precast concrete pile; 2. After the plug is inserted into the intermediate nut and clamped with the snap ring, the plug, the snap ring and the intermediate nut do not form complete fitting of the wedge surface (the force between the plug and the snap ring is very small), so that the plug of the plug rod extrudes the snap ring when the plug rod is subjected to pulling force, shearing force or bending force, and thus axial slip occurs between the snap ring and the plug, which causes axial gap at the whole or part of the mechanical joint at the pile connection end face when the precast concrete pile is connected by using the mechanical joint and is subjected to pulling force, shearing force or bending force, and thus axial gap is generated at the mechanical joint connection of the precast concrete pile, which causes cracks at the mechanical joint connection of the precast concrete pile; 3. As shown in Figure 27 , the clamping surfaces of the snap ring and the plug are both tapered cylindrical surfaces, and the clamping positions of the snap ring and the plug are uncertain, so that the clamping surface of the snap ring and the clamping surface of the plug do not completely fit when the snap ring is clamped with the plug. As shown in Figure 28As shown in the figure, Q1 to Q5 curves represent the cross-sectional radius curves of the clamping surface of the plug at different positions, and J curve represents the cross-sectional radius curve of the clamping ring at a certain position. As shown in the figure, when J curve is at Q1 position, J curve completely matches Q1, and when J curve is at Q2 to Q5, the gap between J curve and Q curve gradually increases, that is, when the clamping ring is at different positions of the plug, the clamping state of the clamping ring and the plug is different, that is, it cannot be guaranteed that the clamping surface of the clamping ring completely matches the clamping surface of the plug. That is, the clamping ring and the plug are in line contact, and when the mechanical joint is subjected to pulling force, shearing force or bending force, axial slip occurs between the clamping ring and the plug or the clamping ring is partially embedded into the plug (or the clamping ring is deformed under force), thereby causing axial gap of the mechanical joint, that is, when the mechanical joint is used for connecting precast concrete piles and subjected to pulling force, shearing force or bending force, axial gap also occurs between the connecting end surfaces of the precast concrete piles, causing cracks at the connecting position of the mechanical joint of the precast concrete piles; 4, since the large nut and the intermediate nut are connected through threads, and the small nut and the plug rod are connected through threads, the threads also have a certain axial gap, and when the mechanical joint is subjected to pulling force, shearing force or bending force, the axial gap of the threads also causes axial gap between the connecting end surfaces of the precast concrete piles, causing cracks at the connecting position of the mechanical joint of the precast concrete piles. The mechanical structure has the above-mentioned various deficiencies, therefore, when the mechanical joint is used for connecting precast concrete piles, it is easy to cause the precast concrete pile connection to fail to meet the requirements of the following provisions in the Technical Standard for Prestressed Concrete Pipe Piles (JGJ / T 406-2017): Article 5.1.7 stipulates that the crack control level of prestressed pipe piles with strict requirements of no cracks should be level one; Article 5.1.8 stipulates that the crack control level of pipe piles under axial tension should be level one; the crack control level of pipe piles under bending should be level two in weak corrosion environment and above, and level one in medium and strong corrosion environment and above.

[0010] The existing mechanical joint has the problem of axial gap, so that when it is used for connecting precast concrete piles and subjected to pulling force, shearing force and / or bending force, the connecting mechanism of the above-mentioned mechanical joint of the precast concrete pile will produce gap, causing cracks at the joint of the precast concrete pile. The precast pile foundation is a hidden underground project, and the precast pile itself cannot be repaired.

[0011] Safety hazards of building pile foundation caused by cracks in the joint of the precast concrete pile:

[0012] When the precast concrete pile bears the bending resistance and the shearing force, the axial gap of the mechanical joint at the joint of the precast concrete pile causes cracks at the joint, which further causes the pile and the pile to be not on the same axis, and makes the local eccentric force on the connecting end surface of the pile; the concrete at the end surface of the pile is damaged or cracked, and the building pile foundation has a safety hazard.

[0013] When the precast concrete pile bears the tension, the axial gap caused by the mechanical joint cannot be ensured to be completely consistent, and the axial tension bearing capacity design value of the precast pile is considered according to the number of main reinforcement (the number of mechanical joints); the mechanical joint is broken one by one when it bears the tension, and the building pile foundation has a safety hazard.

[0014] When the precast concrete pile bears the bending resistance, the shearing force and the tension, the axial gap at the joint of the precast concrete pile causes cracks at the joint, which causes the underground water to invade and corrode the mechanical connecting piece and / or the main reinforcement of the precast pile, and makes it difficult to guarantee the durability of the precast pile. Specifically, according to the annual corrosion rate of steel pile in Table 4.1.18 of the Technical Code for Building Pile Foundation - JGJ94-2008, when the steel pile is above the ground and in the environment without corrosive gas or corrosive volatile medium, the single-side corrosion rate is 0.05-0.1mm / y; when the steel pile is below the ground and above the water level, the single-side corrosion rate is 0.05mm / y; when the steel pile is below the ground and below the water level, the single-side corrosion rate is 0.03mm / y; when the steel pile is below the ground and in the water level fluctuation area, the single-side corrosion rate is 0.1-0.3mm / y; therefore, when the precast concrete pile has cracks due to the axial gap of the mechanical joint, the mechanical joint and / or the main reinforcement will be rapidly corroded, which makes it difficult to guarantee the durability of the precast pile, and the severity of the harm is self-evident. SUMMARY

[0015] The present application is directed to the problem that the axial gap caused by the existing mechanical joint connection mechanism causes cracks at the joint of the precast concrete pile, which causes the corrosion of the main reinforcement and / or the mechanical joint, the local compression of the pile end surface and other problems, and a pre-tightening mechanical joint with multi-tooth card clamping is proposed to solve the problem of safety hazard caused by the axial gap of the existing mechanical joint connection.

[0016] The technical means adopted by the present application are as follows:

[0017] A pre-tightening mechanical joint with multi-tooth card clamping, comprising,

[0018] A plug rod, one end of the plug rod is a plug, and the outer wall of the plug is provided with a first tooth;

[0019] A large nut, the large nut is provided with a containing cavity;

[0020] The pre-tightening nut is internally provided with an insertion cavity, the insertion cavity is internally provided with a plurality of toothed card accommodating grooves, the outer wall of the pre-tightening nut is provided with a pre-tightening nut threaded connection part and a pre-tightening nut driving part; the pre-tightening nut threaded connection part is arranged in the large nut and is threadedly connected with the accommodating cavity, and at least part of the pre-tightening nut driving part is located outside the accommodating cavity.

[0021] The plurality of toothed card assemblies are arranged in the plurality of toothed card accommodating grooves, the plurality of toothed card assemblies comprise a plurality of circumferentially spliced cards and a radially elastic elastic ring sleeved outside the cards, the plurality of cards surround a clamping cavity, and the plurality of cards can be expanded and contracted in the plurality of toothed card accommodating grooves, the inner wall of the card is provided with second teeth, and the plug can be inserted into the clamping cavity and make the first teeth and the second teeth clamped to realize the clamping of the plug and the plurality of toothed clamping assemblies.

[0022] When the plurality of toothed clamping assemblies are clamped with 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 axially along the large nut, thereby locking the plug and the pre-tightening nut in the axial direction of the large nut.

[0023] Further, the pre-tightening nut driving part is provided with a driving tooth, and the driving part is a lead screw, and the lead screw is provided with a meshing tooth capable of meshing with the driving tooth.

[0024] Further, the driving tooth is a straight tooth parallel to the pre-tightening nut axis or an inclined tooth at an angle to the pre-tightening nut axis.

[0025] Further, during the process that the plug is inserted into the clamping cavity, the maximum outer diameter of the plurality of cards when expanded is less than or equal to the inner diameter of the plurality of toothed card accommodating grooves.

[0026] The minimum inner diameter of the plurality of cards when expanded is less than or equal to the minimum inner diameter of the insertion cavity.

[0027] Further, the inner wall of the side of the plurality of toothed card accommodating grooves close to the plug insertion end is a first abutting surface, the side of the card close to the plug insertion end is provided with a second abutting surface, and when the plug and the pre-tightening nut are locked in the axial direction of the large nut, the first abutting surface and the second abutting surface abut each other.

[0028] Further, the first abutting surface and the second abutting surface are both tapered surfaces.

[0029] Further, the first teeth and the second teeth are sawtooth teeth or pagoda teeth.

[0030] Further, the threaded connection between the pre-tightening nut and the large nut is a loose threaded connection before the plug and the multi-toothed card assembly are locked in the axial direction of the large nut.

[0031] Further, the tensile strength of the connection between the plug and the multi-toothed card assembly is greater than or equal to the tensile strength of any of the main reinforcement, the large nut, and the small nut after the plug and the multi-toothed card assembly are locked in the axial direction of the large nut.

[0032] Further, the small nut is further included for connection with the plug base of the plug rod.

[0033] A precast concrete pile includes a precast concrete pile body, a main reinforcement, and a multi-toothed card jointed pre-tightening mechanical joint according to any one of claims 1 to 10.

[0034] The main reinforcement is arranged in the precast concrete pile body, and the precast concrete pile body has the large nut at one end, and the pre-tightening nut and the multi-toothed card joint assembly are arranged in the large nut.

[0035] The other end of the precast concrete pile body is provided with the plug rod.

[0036] The end of the precast concrete pile body is provided with a driving component accommodating groove.

[0037] When two adjacent precast concrete piles are connected, one end of the driving component accommodating groove is in communication with the outer wall of the precast concrete pile body, and the other end extends to the end of the pre-tightening nut, so that after the driving component is inserted into the driving component accommodating groove from the outer wall of the precast concrete pile body, the driving component can interact with the pre-tightening nut driving part, so that the pre-tightening nut rotates and moves axially along the large nut, thereby locking the plug and the pre-tightening nut in the axial direction of the large nut.

[0038] Further, one end of the precast concrete pile body provided with the plug rod is further provided with a small nut, and one end of the large nut and the small nut is connected with two ends of the main reinforcement, respectively, and the other end of the plug rod is threadedly connected with the small nut.

[0039] Further, after the driving component drives the pre-tightening nut to rotate and locks the plug and the pre-tightening nut in the axial direction of the large nut, the driving component remains in or moves out of the driving component accommodating groove.

[0040] Further, structural glue is further injected into the connection end face of the precast concrete pile body and the multi-toothed card jointed pre-tightening mechanical joint.

[0041] A connection method of a precast concrete pile includes the following steps:

[0042] The end of the precast concrete pile provided with the insertion rod is moved towards the end of the adjacent precast concrete pile provided with the pre-tightening nut, and the plug of the insertion rod is inserted into the insertion cavity of the pre-tightening nut to realize the clamping of the plug and the multi-tooth card assembly;

[0043] The pre-tightening nut driving part is driven by the insertion of the outer wall of the precast concrete pile into the driving part, so that the pre-tightening nut is rotated and moved axially along 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 joint with multi-tooth card clamping disclosed in the application has the following beneficial effects: the pre-tightening mechanical joint with multi-tooth card clamping disclosed in the application is provided with a pre-tightening nut driving part on the pre-tightening nut, which can be driven from the side of the pre-tightening nut by a driving part after the plug is inserted into the insertion cavity, so that the pre-tightening nut moves axially along the large nut, thereby locking the plug and the pre-tightening nut in the axial direction of the large nut, effectively eliminating the axial gap between the plug, the multi-tooth card assembly and the pre-tightening nut, and further, since the pre-tightening nut, the insertion rod and the multi-tooth card assembly are locked in the axial direction, a certain axial force (tightening force) is generated in the locking process, under the action of which the axial gap between the pre-tightening nut, the insertion rod, the large nut, the multi-tooth card assembly and the small nut can be effectively eliminated, so that when the precast concrete pile is connected by using the mechanical joint disclosed in the application, the connection of the precast concrete pile will not crack and generate cracks under the action of pulling force, shearing force or bending force, so that the connection of the precast concrete pile by using the mechanical joint disclosed in the application can meet the relevant requirements for crack grade control in the Technical Standard for Prestressed Concrete Pipe Pile JGJ / T 406-2017, and the problem of cracks in the joint of the precast concrete pile caused by the gap generated by the connection mechanism of the existing mechanical joint is eliminated. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1 It is an axial view of the pre-tightening mechanical joint with multi-tooth card clamping disclosed in the application.

[0046] Figure 2 It is a front view of the pre-tightening mechanical joint with multi-tooth card clamping disclosed in the application.

[0047] Figure 3 It is a sectional view of the pre-tightening mechanical joint with multi-tooth card clamping disclosed in the application.

[0048] Figure 4The schematic view of the pre-tightening mechanical joint of the multi-tooth card clamping of the present application in the state that the plug and the clamping spring are not axially locked after the plug is inserted into the pre-tightening nut;

[0049] Figure 5 The partial enlarged view of A in the present application; Figure 4

[0050] Figure 6 The schematic view of the pre-tightening mechanical joint of the multi-tooth card clamping of the present application in the state that the plug and the clamping spring are axially locked after the plug is inserted into the pre-tightening nut;

[0051] Figure 7 The partial enlarged view of B in the present application; Figure 6

[0052] Figure 8 The schematic view of the pre-tightening nut of the pre-tightening mechanical joint of the multi-tooth card clamping of the present application;

[0053] Figure 9 The sectional view of the pre-tightening nut of the pre-tightening mechanical joint of the multi-tooth card clamping of the present application;

[0054] Figure 10 The top view of the pre-tightening nut of the pre-tightening mechanical joint of the multi-tooth card clamping of the present application;

[0055] Figure 11 The front view of the driving component of the pre-tightening mechanical joint of the multi-tooth card clamping of the present application;

[0056] Figure 12 The right view of the driving component of the pre-tightening mechanical joint of the multi-tooth card clamping of the present application;

[0057] Figure 13 The front view of the multi-tooth card assembly of the pre-tightening mechanical joint of the multi-tooth card clamping of the present application;

[0058] Figure 14 The sectional view of the multi-tooth card assembly of the pre-tightening mechanical joint of the multi-tooth card clamping of the present application;

[0059] Figure 15 The front view of the large nut of the pre-tightening mechanical joint of the multi-tooth card clamping of the present application;

[0060] Figure 16 The sectional view of the large nut of the pre-tightening mechanical joint of the multi-tooth card clamping of the present application;

[0061] Figure 17 The structure view of the insertion rod of the pre-tightening mechanical joint of the multi-tooth card clamping of the present application;

[0062] Figure 18 ​​Structure diagram of precast concrete pile connection with the disclosed multi-toothed card clamping pre-tightening mechanical joint, in which the number of piles is two sections;

[0063] Figure 19 Sectional view of precast concrete pile connection with the disclosed multi-toothed card clamping pre-tightening mechanical joint;

[0064] Figure 20 Structure diagram of the disclosed multi-toothed card clamping pre-tightening mechanical joint; Figure 19 Local enlarged view at D in the middle;

[0065] Figure 21 End view of precast concrete pile connection with the disclosed multi-toothed card clamping pre-tightening mechanical joint;

[0066] Figure 22 Structure diagram of the disclosed multi-toothed card clamping pre-tightening mechanical joint; Figure 21 Local enlarged view at F in the middle;

[0067] Figure 23 Structure diagram of the existing first mechanical joint, in which the plug is in an over-inserted state;

[0068] Figure 24 Structure diagram of the existing first mechanical joint, in which the plug is in an under-inserted state;

[0069] Figure 25 Structure diagram of the existing second mechanical joint, in which the plug rod axis and the middle nut axis are not collinear in the plug connection process;

[0070] Figure 26 Structure diagram of the existing second mechanical joint, in which the plug of the plug rod first contacts the lower card, so that the lower card cannot enter between the plug and the middle nut;

[0071] Figure 27 Structure diagram of the existing second mechanical joint, in which multiple cards are clamped at different positions of the plug and the middle nut;

[0072] Figure 28 Structure diagram of the existing second mechanical joint, in which the card and the plug clamping surface are in contact.

[0073] In the figure:

[0074] 1, the plug rod; 10, the plug; 11, the first tooth; 12, the plug rod base; 2, the large nut; 20, the accommodation cavity; 21, the small nut; 3, the multi-tooth card assembly; 30, the card; 31, the elastic ring; 32, the clamping cavity; 33, the second tooth; 34, the second abutting surface; 4, the pre-tightening nut; 40, the insertion cavity; 41, the first abutting surface; 42, the multi-tooth card accommodation groove; 43, the plug insertion end; 45, the pre-tightening nut threaded connection part; 46, the pre-tightening nut driving part; 461, the driving tooth; 6, the driving part; 60, the screw rod; 600, the occlusion tooth; 8, the precast concrete pile; 80, the precast concrete pile body; 81, the main reinforcement; 82, the driving part accommodation groove. DETAILED DESCRIPTION

[0075] As Figure 1 , Figure 2 and Figure 3 show the multi-tooth card clamping pre-tightening mechanical joint disclosed by the application, comprising a plug rod 1, one end of the plug rod 1 being a plug 10, the outer wall of the plug being provided with a first tooth 11, as shown in Figure 17 ;

[0076] a large nut 2, the large nut 2 being provided with an accommodation cavity 20, as shown in Figure 15 , Figure 16 ;

[0077] a pre-tightening nut 4, the pre-tightening nut 4 being provided with an insertion cavity 40, the insertion cavity 40 being provided with a multi-tooth card accommodation groove 42, the outer wall of the pre-tightening nut 4 being provided with a pre-tightening nut threaded connection part 45 and a pre-tightening nut driving part 46; the pre-tightening nut threaded connection part 45 being arranged in the large nut 2 and being threadedly connected with the accommodation cavity 20, and at least part of the pre-tightening nut driving part 46 being located outside the accommodation cavity 20;

[0078] a multi-tooth card assembly 3, the multi-tooth card assembly 3 being arranged in the multi-tooth card accommodation groove 42, as shown in Figure 13 , Figure 14 ; the multi-tooth card assembly 3 comprising a plurality of circumferentially spliced cards 30 and an elastic ring 31 having radial elasticity and being sleeved outside the cards 30, the elastic ring 31 being a circular ring structure made of elastic material, and being provided with an opening on the circular ring, so that the elastic ring can be expanded or contracted; in this embodiment, the card has three pieces, and the number of cards can be selected according to requirements; a groove structure is processed on the outer side wall of the card, so that the elastic ring can be sleeved in the groove on the outer side wall of the card; a plurality of the cards 30 surround a clamping cavity 32, and a plurality of the cards 30 can be expanded and contracted in the multi-tooth card accommodation groove 42; the inner wall of the card 30 is provided with a second tooth 33; the plug 10 can be inserted into the clamping cavity 32 and make the first tooth 11 and the second tooth 33 clamped to realize the clamping of the plug 10 and the multi-tooth card assembly 3.

[0079] When the multi-tooth clamping assembly 3 is clamped with the plug 10, the driving component 6 can drive the pretightening nut driving part 46 from the side of the pretightening nut 4, so that the pretightening nut 4 rotates and moves axially along the large nut 2, thereby locking the plug 10 and the pretightening nut 4 in the axial direction of the large nut 2.

[0080] The clamping and clamping pretightening mechanical joint disclosed in the present application is provided with a pretightening nut driving part 46 on the pretightening nut 4, as shown in Figure 4 and Figure 6 After the plug 10 of the insertion rod 1 is inserted into the multi-tooth clamping assembly 3 in the multi-tooth clamping slot 42 of the pretightening nut 4 and radially clamped with the multi-tooth clamping assembly 3 placed in the multi-tooth clamping slot 42, the pretightening nut driving part 46 can be driven from the side of the pretightening nut 4 by the driving component 6, as shown in Figure 4 schematically shows the movement process, specifically, after the plug is inserted into the multi-tooth clamping assembly in the pretightening nut, there is a certain axial gap L between the clamping surface of the multi-tooth clamping assembly 3 and the plug 10, as shown in Figure 5 Under the action of an external force, the driving component 6 rotates, so that the pretightening nut 4 rotates radially (indicated by arrow B in Figure 4 ) and moves axially along the large nut 2 (indicated by arrow C in Figure 4 ), thereby locking the plug 10 and the pretightening nut in the axial direction of the large nut 2, that is, after the plug 10 of the insertion rod 1 is clamped with the multi-tooth clamping assembly 3, the pretightening nut 4 can be driven in the axial direction of the large nut 2 by the driving component 6, thereby eliminating the axial gap L between the plug 10, the multi-tooth clamping assembly 3 and the pretightening nut 4 through the axial movement of the pretightening nut 4, as shown in Figure 7 Further, since the pretightening nut, the insertion rod and the multi-tooth clamping assembly are locked in the axial direction, during the locking process, a tightening torque (tightening force) is generated between the pretightening nut and the large nut, which causes a certain axial force in the axial direction between the pretightening nut, the insertion rod and the multi-tooth clamping assembly, under the action of the axial force, the axial gaps between the pretightening nut, the insertion rod, the large nut, the multi-tooth clamping assembly and the small nut, etc. can be effectively eliminated, for example, the axial gap of the threaded connection between the pretightening nut and the large nut (the axial gap of the threaded connection in the area indicated by E2 in Figure 6 ), the axial gap of the threaded connection between the insertion rod base of the insertion rod and the small nut (the axial gap of the threaded connection in the area indicated by E3 in Figure 6The mechanical joint disclosed by the present application can prevent the prefabricated concrete pile from cracking and generating cracks when the prefabricated concrete pile is connected by the mechanical joint disclosed by the present application and subjected to a pulling force, a shearing force or a bending force, that is, the prefabricated concrete pile connected by the mechanical joint disclosed by the present application has high anti-pulling, anti-bending and anti-shearing performance, so that the prefabricated concrete pile connected by the mechanical joint disclosed by the present application can meet the relevant requirements of the crack grade control in the Technical Standard for Prestressed Concrete Pipe Pile JGJ / T 406-2017. The problem that the prefabricated concrete pile connected by the mechanical joint disclosed by the present application can generate cracks due to the gap caused by the connection mechanism of the existing mechanical joint and cause safety hazards of the building pile foundation is eliminated.

[0081] Meanwhile, since the plurality of toothed card accommodating grooves are arranged in the insertion cavity of the pretightening nut, the plurality of toothed card assembly can be directly installed in the plurality of toothed card accommodating grooves of the pretightening nut, so that the two components form an assembly, thereby facilitating the installation of the subsequent mechanical joint, reducing the installation difficulty and saving the cost. Meanwhile, the structure of the plurality of toothed card assembly and the pretightening nut is simple, thereby further reducing the cost. Preferably, the end of the plug is hemispherical, parabolic or circular truncated conical, so as to facilitate the radial expansion of the plurality of toothed card assembly.

[0082] Further, as shown in Figure 8 、 Figure 10 The driving component 6 is a lead screw 60, and the lead screw 60 is provided with a meshing tooth 600 capable of meshing with the driving tooth 461.

[0083] Specifically, in the present embodiment, the pretightening nut driving part 46 is provided with a driving tooth 461, which can be a straight tooth parallel to the axis of the pretightening nut 4 or an inclined tooth at a certain angle with the axis of the pretightening nut, or a straight tooth as shown in Figure 8 Therefore, the driving component 6 can be a lead screw 60, as shown in Figure 11 and Figure 12As shown, the screw rod 60 is provided with engagement teeth 600 capable of engaging with the driving teeth 461, and the precast concrete pile is provided with a driving component accommodating groove 82 communicating with the outer wall of the pile, the other end of the driving component accommodating groove 82 extending to the end of the large nut 2, the screw rod 60 being capable of being inserted between the two sections of the precast concrete pile through the driving component accommodating groove 82, and the engagement teeth 600 on the screw rod 60 being capable of engaging with the pre-tightening nut 4 placed in the large nut 2, the screw rod being driven to rotate at the outer wall of the precast concrete pile, the end of the screw rod 60 being provided with an internal hexagonal hole, a straight slot or a cross-shaped slot and the like structure to facilitate the rotation of the screw rod by a tool, the rotation of the screw rod being capable of driving the pre-tightening nut to rotate through the driving teeth on the pre-tightening nut driving portion, and then realizing the axial movement of the pre-tightening nut to lock the plug and the multi-tooth card assembly in the axial direction, and eliminating the axial gap between the plug, the multi-tooth card assembly and the pre-tightening nut and the like components of the insertion rod. The pre-tightening nut is driven to rotate through the screw rod tooth structure, which not only has a simple structure, but also has a large stroke, so that the pre-tightening nut can move a large stroke in a small space, ensuring the locking performance, and facilitating the operation and control of the axial locking force between the insertion rod and the pre-tightening nut. The straight tooth structure has the advantage of being easy to process, and the helical tooth structure has the advantage that the screw rod can exert a larger circumferential driving force on the pre-tightening nut, thereby facilitating the rotation of the pre-tightening nut to realize the axial movement. The driving teeth can be directly machined on the pre-tightening nut driving portion, or can be a separate structure, i.e. the pre-tightening nut driving portion is provided with an intermediate sleeve, the intermediate sleeve is provided with driving teeth (forming a structure similar to a gear), and the intermediate sleeve and the pre-tightening nut driving portion are connected through a key or the like structure.

[0084] Further, during the process of inserting the plug 10 into the clamping cavity 32, the maximum outer diameter of the plurality of cards 30 when opened is equal to or less than the inner diameter of the multi-tooth card accommodating groove 42, and the minimum inner diameter of the plurality of cards 30 when opened is less than or equal to the minimum inner diameter of the insertion cavity 40. When the maximum outer diameter of the card 30 when opened is equal to the inner diameter of the multi-tooth card accommodating groove 42, the outer wall of the multi-tooth card assembly can be fitted with the inner wall of the pre-tightening nut, and the pre-tightening nut provides radial support to the multi-tooth card assembly and limits the card of the multi-tooth card assembly. At the same time, the minimum inner diameter (the diameter surrounded by the addendum of the second tooth) of the card 30 when opened is less than or equal to the minimum inner diameter of the insertion cavity 40, as shown in Figure 9As shown, the insertion cavity 40 of the pre-tightening nut is a stepped hole structure, the hole diameter near the insertion end of the insertion rod is relatively small, and the hole diameter away from the insertion end of the insertion rod is relatively large. The part of the hole diameter away from the insertion end of the insertion rod that is relatively large forms a multi-tooth card accommodating groove, and the multi-tooth card assembly is placed in the multi-tooth card accommodating groove. In the present application, the minimum inner diameter of the card 30 when opened (the diameter surrounded by the tooth top of the second tooth) is less than or equal to the minimum inner diameter of the insertion cavity 40, that is, the minimum inner diameter of the card 30 when opened (the diameter surrounded by the tooth top of the second tooth) is less than or equal to the hole diameter on the side of the insertion cavity near the insertion end of the insertion rod. Because the minimum inner diameter of the card 30 when opened is less than or equal to the minimum inner diameter of the insertion cavity 40, the card plays a limiting and guiding role for the plug during the plug insertion process. The insertion rod and the pre-tightening nut have a gap (no contact) in the radial direction during and / or after the insertion of the multi-tooth card assembly into the insertion rod, that is, the force between the insertion rod and the pre-tightening nut is reduced or eliminated, so that the driving component drives the pre-tightening nut to rotate from the side, and the pre-tightening nut moves in the axial direction of the large nut, thereby locking the plug and the clasp in the axial direction of the large nut.

[0085] Further, the inner wall of the multi-tooth card accommodating groove 42 on the side near the plug insertion end 43 is a first abutting surface 41, and the side of the card 30 towards the plug insertion end 43 is provided with a second abutting surface 34. When the plug 10 and the pre-tightening nut 4 are locked in the axial direction of the large nut 2, the first abutting surface 41 and the second abutting surface 34 abut each other. At this time, the first abutting surface and the second abutting surface are completely fitted, and the gap between the multi-tooth card assembly and the plug is eliminated. The use of the mechanical joint disclosed in the present application for connecting precast concrete piles can provide the pile connection with high anti-pullout, anti-bending and anti-shear performance, so that the use of the mechanical joint disclosed in the present application for connecting precast concrete piles can meet the relevant requirements for crack grade control in the Technical Standard for Prestressed Concrete Pipe Piles JGJ / T406-2017. And the problem of cracks at the joint of the precast concrete pile caused by the gap generated by the connection mechanism of the existing mechanical joint, which causes safety hazards to the building pile foundation, is solved.

[0086] Further, the first abutting surface 41 and the second abutting surface 34 are both conical surfaces. Because the first abutting surface and the second abutting surface are both conical surfaces, when the pre-tightening nut and the multi-tooth card assembly are axially locked, the first abutting surface 41 generates a force perpendicular to the abutting surface on the second abutting surface 34. The generated force can be decomposed into a force perpendicular to the card and making the card tighten inward, and a vertical downward force. The inner wall of the pre-tightening nut forms a holding force on the multi-tooth card assembly, so the connection strength of the pre-tightening nut and the multi-tooth card assembly is enhanced, and the anti-pullout, anti-bending and anti-shear performance is also enhanced.

[0087] Further, the first tooth 11 and the second tooth 33 are sawtooth or pagoda teeth, which make the connection between the plug and the multi-tooth card assembly more close and firm, and ensure the connection effect between the plug and the multi-tooth card assembly.

[0088] Further, before the plug 10 and the multi-tooth card assembly are locked in the axial direction of the large nut 2, the threaded connection between the pre-tightening nut 4 and the large nut 2 is a loose threaded connection.

[0089] Specifically, the tolerances of the internal threads on the inner wall of the accommodating cavity of the large nut and the external threads on the outer wall of the pre-tightening nut can be reasonably selected according to the needs, so that the threaded connection between the pre-tightening nut and the large nut is a loose threaded connection. Since the threaded connection between the pre-tightening nut and the large nut is a loose threaded connection, the force between the pre-tightening nut and the large nut is relatively small before the plug and the multi-tooth card assembly are locked, thereby facilitating the driving component to drive the pre-tightening nut to rotate from the side, making the pre-tightening nut move in the axial direction of the large nut, and thereby locking the plug and the multi-tooth card assembly in the axial direction of the large nut.

[0090] Further, after the plug 10 and the multi-tooth card assembly 3 are locked in the axial direction of the large nut 2, the tensile strength of the connection between the plug and the multi-tooth card assembly is greater than or equal to the tensile strength of any one of the main reinforcement, the large nut and the small nut. Preferably, after the plug 10 and the multi-tooth card assembly 3 are locked in the axial direction of the large nut 2, the connection between the plug and the multi-tooth card assembly has no ductile deformation when bearing a pulling force of 11.7 Mpa.

[0091] In the present application, after the plug 10 and the multi-tooth card assembly 3 are locked in the axial direction of the large nut 2, the tensile strength of the connection between the plug and the card ring is greater than or equal to the tensile strength of any one of the main reinforcement, the large nut and the small nut, and the connection between the plug and the multi-tooth card assembly has no ductile deformation when bearing a pulling force of 11.7 Mpa, so that the precast concrete pile with the multi-tooth card assembly clamped pre-tightening mechanical joint disclosed in the present application will not have ductile deformation before the pulling force that causes the main reinforcement to have ductile deformation, so that no cracks or gaps will be generated between the end faces of the two precast piles, and the multi-tooth card clamped pre-tightening mechanical joint disclosed in the present application can be reliably connected without being damaged before the main reinforcement is ductile and is pulled off, further ensuring the connection performance of the precast concrete pile connected by the multi-tooth card clamped pre-tightening mechanical joint disclosed in the present application. Specifically, the relationship between the type of pile and the pre-stressed main reinforcement is specified in detail in the pre-stressed concrete square pile reinforcement and mechanical performance table in the national building standard design drawing set “precast concrete square pile” (drawing set number: 20G361), for example, it is specified that the pre-stressed main reinforcement of the pile with a pile cross section of 600x600 is 24ΦD 12.6; in prestressed concrete square pile body axial compression, normal section bending capacity in detail stipulates the pile section type and the pile body axial tension bearing capacity design value Nt (kN), in the table, it is stipulated that the pile section is 600x600 B-shaped pile, the pile body axial tension bearing capacity design value is 2544kN, from the above data, the tension bearing capacity design value of the prestressed main reinforcement of the prefabricated pile is 2544 / 24 = 10.6kN; 10.6x1.1 = 11.66 = 11.7kN, that is, the pre-tightening mechanical joint of the multi-tooth card clamping disclosed in the application is within 11.7kN under the tension pull, the main reinforcement of the prefabricated concrete pile and the pre-tightening mechanical joint of the multi-tooth card clamping are all without ductile deformation, and there is no slip between the parts of the mechanical joint, so that there is no gap between the connecting end faces of the prefabricated concrete pile, thereby ensuring the connecting performance of the prefabricated concrete pile.

[0092] Further, a small nut 21 is included for connecting with the insertion rod base 12 of the insertion rod 1.

[0093] Specifically, in the embodiment, the insertion rod 1 is fixed at one end of the prefabricated concrete pile through the small nut 21, and the large nut 2 is fixed at the other end of the prefabricated concrete pile, the large nut 2 and the small nut 21 are respectively fixedly connected with the two ends of the main reinforcement in the prefabricated concrete pile, the large nut is provided with a positioning sleeve and a pre-tightening nut and the like components, and the adjacent two sections of the prefabricated concrete pile can be quickly connected through the pre-tightening mechanical joint disclosed in the application.

[0094] Embodiment 2

[0095] As shown in Figure 18 , Figure 19 , Figure 20 , Figure 21 and Figure 22 , a prefabricated concrete pile disclosed in the application comprises a prefabricated concrete pile body 80, a main reinforcement 81 and a multi-tooth card clamping pre-tightening mechanical joint of the application;

[0096] The main reinforcement 81 is arranged in the prefabricated concrete pile body 80, one end of the prefabricated concrete pile body 80 is provided with the large nut 2, and the large nut 2 is provided with the pre-tightening nut 4 and the multi-tooth clamping assembly 3;

[0097] The other end of the prefabricated concrete pile body 80 is provided with the insertion rod 1;

[0098] The end of the prefabricated concrete pile body 80 is provided with a driving part accommodating groove 82;

[0099] When two adjacent prefabricated concrete piles are connected, one end of the driving part accommodating groove 82 communicates with the outer wall of the prefabricated concrete pile body 80, and the other end extends to the end of the pretightening nut 4, so that after the driving part 6 is inserted into the driving part accommodating groove 82 from the outer wall of the prefabricated concrete pile body 80, the driving part 6 can interact with the pretightening nut driving part 46, so that the pretightening nut 4 rotates and moves axially along the large nut 2, thereby locking the plug 10 and the pretightening nut 4 in the axial direction of the large nut 2.

[0100] The clamping and pre-tightening mechanical joint of the application discloses a clamping ring, and the pre-tightening nut is provided with a pre-tightening nut driving part. After the plug of the insertion rod is inserted into the insertion cavity of the intermediate pre-tightening nut and radially clamped with the multi-tooth clamping assembly placed in the accommodating cavity, the pre-tightening nut is driven from the side of the pre-tightening nut by the driving part, so that the pre-tightening nut rotates and moves axially along the large nut, thereby locking the plug and the pre-tightening nut in the axial direction of the large nut. That is, after the plug of the insertion rod is clamped with the multi-tooth clamping assembly, the pre-tightening nut can move in the axial direction of the large nut under the driving of the driving part, thereby eliminating the axial gap between the plug of the insertion rod, the multi-tooth clamping assembly and the pre-tightening nut through the axial movement of the pre-tightening nut. Further, since the pre-tightening nut, the insertion rod and the multi-tooth clamping assembly are locked in the axial direction, a certain axial force is generated in the axial direction during the locking process. Under the action of the axial force, the axial gaps between the pre-tightening nut, the insertion rod, the large nut, the multi-tooth clamping assembly and the small nut, such as the gap between the pre-tightening nut and the large nut in threaded connection, the gap between the insertion rod base of the insertion rod and the small nut in threaded connection, and the gap between the plug of the insertion rod and the multi-tooth clamping assembly, etc., can be effectively eliminated. Therefore, when the prefabricated concrete piles are connected by using the mechanical joint disclosed in the application, the connected part of the prefabricated concrete piles will not crack and generate cracks under the action of pulling force, shearing force or bending force, i.e., the prefabricated concrete pile connection using the mechanical joint disclosed in the application has high anti-pulling, anti-bending and anti-shearing performance, so that the prefabricated concrete pile connection using the mechanical joint disclosed in the application can meet the relevant requirements for crack grade control in the Technical Standard for Prestressed Concrete Pipe Piles JGJ / T 406-2017. The problem of cracks in the connected part of the prefabricated concrete piles due to the gap generated by the connection mechanism of the existing mechanical joint is also eliminated, thereby avoiding the safety hazards of building pile foundations.

[0101] Further, the precast concrete pile body 80 is provided with a small nut 21 at one end of the insertion rod 1, and the large nut 2 and the small nut 21 are respectively connected to the two ends of the main reinforcement 81, and the insertion rod 1 is threadedly connected to the other end of the small nut 21. That is, the mechanical joint is arranged at the two ends of the main reinforcement, so that the main reinforcement and the mechanical joint are coaxial, and thus the main reinforcement and the mechanical joint are on the same axis when they are stressed, thereby improving the anti-pulling performance of the pile. The driving component accommodating groove 82 can also be arranged at the end of the precast concrete pile provided with the small nut, and when the driving component accommodating groove 82 is arranged at the end of the precast concrete pile provided with the small nut, the end of the end of the precast concrete pile provided with the small nut is provided with a pre-tightening nut accommodating 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 driving component accommodating groove 82 communicates with the precast concrete pile, and the other end communicates with the driving component accommodating groove 82, thereby enabling the driving component to drive the pre-tightening nut to rotate.

[0102] Further, after the driving component 6 drives the pre-tightening nut 4 to rotate and locks the insertion head 10 and the pre-tightening nut 4 in the axial direction of the large nut 2, the driving component 6 remains in or moves out of the driving component accommodating groove 82.

[0103] Specifically, when the precast concrete piles are connected, a plurality of pre-tightening nuts on the precast concrete piles can be driven to rotate in sequence by one screw rod, so as to achieve axial locking of all mechanical joints, eliminate axial gaps, improve the anti-pulling ability of the pile, and the screw rod can be reused, thereby saving use cost. Each mechanical joint can also be driven by one screw rod when the precast concrete piles are connected, and when the screw rod drives the pre-tightening nut to rotate and achieves axial locking, the screw rod remains in the driving component accommodating groove, that is, the screw rod is not taken out of the driving component accommodating groove. Since a plurality of screw rod structures are arranged between the two precast concrete piles, the compression resistance of the end of the precast pile is further improved.

[0104] Further, structural glue is injected into the pre-tightening mechanical joint of the connecting end face of the precast concrete pile body 80 and the multi-tooth card assembly, and the structural glue can fill, bond and seal various grooves of the connecting end face, the mechanical joint and the end face, thereby further improving the connection performance and corrosion resistance between the piles.

[0105] Embodiment 3

[0106] A connecting method of the precast concrete pile according to the present application, comprising the following steps:

[0107] Moving the end of the precast concrete pile provided with the insertion rod to the end of the adjacent precast concrete pile provided with the pre-tightening nut, and inserting the insertion head of the insertion rod into the insertion cavity of the pre-tightening nut to realize the clamping of the insertion head and the multi-tooth card assembly;

[0108] The driving part is inserted into the outer wall of the precast concrete pile, and the driving part drives the driving part of the pre-tightening nut, so that the pre-tightening nut rotates and moves axially along the large nut, thereby locking the plug and the pre-tightening nut in the axial direction of the large nut.

[0109] When the driving part (screw rod) drives the pre-tightening nut to rotate, the following two cases exist: 1. When the force generated by the threaded connection between the pre-tightening nut and the large nut is small, that is, the connection between the pre-tightening nut and the large nut is loose, the screw rod engages with the driving teeth on the driving part of the pre-tightening nut during the process of entering the driving part accommodating groove, and drives the pre-tightening nut to start rotating and moving axially along the large nut. When the pre-tightening nut achieves axial locking between the multi-tooth clamping assembly and the plug, the pre-tightening nut stops rotating. At this time, the screw rod moves into the driving part accommodating groove under the action of the driving tooth structure, until the end of the screw rod abuts against the end of the accommodating groove. At this time, when the screw rod is continuously driven, the interaction between the screw rod and the driving teeth will generate a pre-tightening force on the plug by the pre-tightening nut, so that a pre-pressure is generated at the connection of the precast concrete pile, thereby preventing buckling deformation when a certain force is applied after the pile is connected, and improving the strength of the precast concrete pile connection. 2. When the force generated by the threaded connection between the pre-tightening nut and the large nut is large, that is, the connection between the pre-tightening nut and the large nut is tight, the screw rod engages with the driving teeth during the process of entering the driving part accommodating groove. At this time, the driving tooth structure cannot drive the pre-tightening nut to rotate, and the driving tooth moves into the driving part accommodating groove under the action of the tooth structure, until the end of the screw rod abuts against the end of the accommodating groove. The screw rod starts to drive the pre-tightening nut to rotate through the tooth structure to achieve axial locking between the multi-tooth clamping assembly and the plug, thereby eliminating the axial gap between the plug, the multi-tooth clamping assembly and the pre-tightening nut through the axial movement of the pre-tightening nut, and ensuring the strength of the precast pile connection. Further, since the pre-tightening nut, the plug and the multi-tooth clamping assembly are locked in the axial direction, a tightening force is generated between the pre-tightening nut and the large nut during the locking process, so that a certain axial force is generated in the axial direction of the pre-tightening nut, the plug and the multi-tooth clamping assembly. Under the action of this axial force, the axial gaps between the pre-tightening nut, the plug, the large nut, the multi-tooth clamping assembly and the small nut, etc. can be effectively eliminated, such as the gap of the threaded connection between the pre-tightening nut and the large nut, the gap of the threaded connection between the plug base of the plug and the small nut, the gap between the plug of the plug and the multi-tooth clamping assembly, etc. Further, the connection performance of the mechanical joint is further improved, and the pullout performance of the precast concrete pile connected through the pre-tightening mechanical joint of the multi-tooth clamping is improved.

[0110] The above merely describes preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art, according to the technical solution and inventive concept of the present application, makes equivalent replacement or change within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A multi-toothed card jointed pretension mechanical joint, characterized by: The utility model relates to a kind of pre-tightening nut driving devices, including, Plug rod (1), one end of the plug rod (1) is plug (10), the outer wall of the plug is equipped with first tooth (11); Large nut (2), the large nut (2) is equipped with accommodating cavity (20) in; Pre-tightening nut (4), the pre-tightening nut (4) is equipped with insertion cavity (40) in, the insertion cavity (40) is equipped with multiple-tooth card accommodating groove (42) in, the outer wall of the pre-tightening nut (4) is equipped with pre-tightening nut threaded connection part (45) and pre-tightening nut driving part (46);The pre-tightening nut threaded connection part (45) is located in the large nut (2) and is connected with the accommodating cavity (20) threadedly, and at least part of the pre-tightening nut driving part (46) is located outside the accommodating cavity (20); Multiple-tooth card assembly (3), the multiple-tooth card assembly (3) is placed in the multiple-tooth card accommodating groove (42), and the multiple-tooth card assembly (3) includes multiple circumferential splicing cards (30) and the elastic ring (31) with radial elasticity of the card (30) outside, multiple the card (30) surrounds and forms card joint cavity (32), and multiple the card (30) can be opened and contracted in the multiple-tooth card accommodating groove (42), the inner wall of the card (30) is equipped with second tooth (33), the plug (10) can be inserted into the card joint cavity (32) and make the first tooth (11) with the second tooth (33) is engaged to realize the plug (10) with the multiple-tooth card assembly (3) is clamped; When the multiple-tooth card assembly (3) is clamped with the plug (10), 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), so as to eliminate the gap between the plug (10) and the pre-tightening nut (4) in the axial direction of the large nut (2), and lock the plug (10) and the pre-tightening nut (4) in the axial direction of the large nut (2).

2. The multi-toothed card-engageable pretension mechanical joint of claim 1, wherein: The pre-tightening nut driving part (46) is equipped with driving tooth (461), and the driving component (6) is a lead screw (60), and the lead screw (60) is equipped with engagement tooth (600) that can be engaged with the driving tooth (461).

3. The multi-toothed card-engageable pretension mechanical joint of claim 2, wherein: The driving tooth (461) is straight tooth parallel to the axis of the pre-tightening nut (4) or oblique tooth at a certain angle with the axis of the pre-tightening nut.

4. The multi-pinned card carded pretension mechanical joint according to any one of claims 1 to 3, characterized in that: During the process that the plug (10) is inserted into the card joint cavity (32), the maximum outer diameter of multiple the card (30) when being opened is less than or equal to the inner diameter of the multiple-tooth card accommodating groove (42); The minimum inner diameter of multiple the card (30) when being opened is less than or equal to the minimum inner diameter of the insertion cavity (40).

5. The multi-pronged card-to-card pretensioned mechanical joint of claim 4, wherein: The multi-tooth card accommodating groove (42) is provided with a first abutting surface (41) on the inner wall of the side close to the plug insertion end (43), and the card (30) is provided with a second abutting surface (34) on the side close to the plug insertion end (43), and when the plug (10) and the pre-tightening nut (4) are locked in the axial direction of the large nut (2), the first abutting surface (41) and the second abutting surface (34) abut against each other.

6. The multi-pronged card-to-card pretensioned mechanical joint of claim 5, wherein: The first abutting surface (41) and the second abutting surface (34) are both conical surfaces.

7. The multi-pronged card-to-card pretensioned mechanical joint of claim 1, wherein: The first tooth (11) and the second tooth (33) are sawtooth-shaped teeth or pagoda-shaped teeth.

8. The multi-pronged card-to-card pretensioned mechanical joint of claim 1, wherein: Before the plug (10) and the multi-tooth card assembly are locked in the axial direction of the large nut (2), the threaded connection between the pre-tightening nut (4) and the large nut (2) is a loose threaded connection.

9. The multi-pronged card-to-card pretensioned mechanical joint of claim 1, wherein: After the plug (10) and the multi-tooth card assembly (3) are locked in the axial direction of the large nut (2), the tensile strength of the connection between the plug and the multi-tooth card assembly is greater than or equal to the tensile strength of any one of the main reinforcement, the large nut, and the small nut.

10. The multi-toothed card laced pretension mechanical joint of claim 1, wherein: It also includes a small nut (21) for connecting with the plug rod base (12) of the plug rod (1).

11. A precast concrete pile characterised in that: It includes a precast concrete pile body (80), a main reinforcement (81), and a multi-tooth card jointed pre-tightening mechanical joint according to any one of claims 1 to 10; The main reinforcement (81) is arranged in 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 multi-tooth card assembly (3) inside. The other end of the precast concrete pile body (80) is provided with the plug rod (1). The end of the precast concrete pile body (80) is provided with a driving component accommodating groove (82). When two adjacent precast concrete piles are connected, one end of the driving component accommodating groove (82) communicates with the outer wall of the precast concrete pile body (80), and the other end extends to the end of the pre-tightening nut (4), so that after the driving component (6) is inserted into the driving component accommodating groove (82) from the outer wall of the precast concrete pile body (80), the driving component (6) can interact with the pre-tightening nut driving part (46), so that the pre-tightening nut (4) rotates and moves in 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. A precast concrete pile according to claim 11, characterised in that: The pre-tightening nut (4) is provided with a small nut (21) at one end of the plug rod (1), and the other end of the small nut (21) is threadedly connected with the plug rod (1).

13. A precast concrete pile according to claim 12, characterised in that: After the driving component (6) drives the pre-tightening nut (4) to rotate and locks the plug (10) and the pre-tightening nut (4) in the axial direction of the large nut (2), the driving component (6) remains in or moves out of the driving component accommodating groove (82).

14. A precast concrete pile according to claim 13, characterised in that: The connecting end surface of the precast concrete pile body (80) and the pre-tightening mechanical joint of the multi-tooth card card joint are also injected with structural glue.

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