A middle nut for a mechanical joint

Abstract

The utility model discloses an intermediate nut for mechanical joint, including the nut body with external thread, the inside of nut body is equipped with the passageway for the plug -in rod passes, one end of nut body is equipped with the first taper surface, the other end of nut body inside is equipped with the second taper surface, be equipped with the inner guide section between the first taper surface and the second taper surface, the inner guide section can be in the plug -in rod insertion process with plug -in rod sliding fit, to the radial movement of plug -in rod is restricted, and guide plug -in rod axial movement, be equipped with the fluid discharge passageway for fluid discharge in the plug -in rod insertion process on the nut body. The utility model discloses through setting up the inner guide section with plug -in rod cooperation in the inner wall, under the condition whether the plug -in rod is inserted fully, can the same degree radial positioning to plug -in rod, cooperate and set up fluid discharge passageway simultaneously, have guaranteed the smooth of plug -in process, have guaranteed the coaxial property of plug -in rod and intermediate nut.

Description

Technical Field

[0001] This utility model relates to the field of precast concrete component technology, specifically to an intermediate nut for a mechanical joint. Background Technology

[0002] During construction, precast concrete components, especially precast concrete piles, often require assembly or connection, particularly multi-section spliced ​​piles. Current methods for splicing precast concrete piles typically involve end-plate welding or mechanical joints for rapid connection. However, existing mechanical joints often rely on intermediate nuts for connection. These nuts cannot adequately provide radial positioning of the insertion rod, especially when the rod is not fully inserted. The tapered positioning surface cannot make sufficient contact with the rod, easily leading to joint failure and reducing the precast concrete pile's pull-out, bending, and shear resistance. Furthermore, since structural adhesive is usually injected during mechanical joint insertion, it is subjected to immense pressure, potentially causing uneven stress distribution and affecting the success rate of the connection. Utility Model Content

[0003] In response to the above problems, this utility model studies and designs an intermediate nut for mechanical joints.

[0004] The technical means adopted in this utility model are as follows:

[0005] An intermediate nut for a mechanical connector includes a nut body with external threads, an internal channel for a probe to pass through, a first conical surface at one end of the nut body, a second conical surface on the inner side of the other end of the nut body, an inner guide section between the first and second conical surfaces, the inner guide section being able to slide with the probe during insertion to constrain radial movement of the probe and guide axial movement of the probe, and a fluid discharge channel on the nut body for fluid discharge during probe insertion.

[0006] Furthermore, the inner guide section is a cylindrical surface that mates with the insert rod, and the fluid discharge channel is a groove provided on the cylindrical surface, the groove extending from the first conical surface to the second conical surface.

[0007] Furthermore, the inner wall of the nut body is provided with three or more grooves, which are evenly distributed along the circumference of the inner wall of the nut body, and the grooves are arranged along the axial direction of the nut body.

[0008] Furthermore, the inner wall of the nut body is provided with more than six grooves.

[0009] Furthermore, the inner guide section is a prismatic surface, and the fluid discharge channel is the edge of the prismatic surface.

[0010] Furthermore, the inner guide section includes an array of protrusions disposed on the inner wall of the nut body, the tops of the array of protrusions being located on the same cylindrical surface, and the fluid discharge channel being the gap between the array of protrusions.

[0011] Furthermore, the cone angle of the first conical surface is 60-90 degrees, the cone angle of the second conical surface is 40-70 degrees, and a cylindrical positioning surface is provided on the outer side of the first conical surface.

[0012] Compared with the prior art, the intermediate nut for the mechanical connector of this utility model, by setting an inner guide section on the inner wall that cooperates with the insertion rod, can provide the same degree of radial positioning for the insertion rod regardless of whether the insertion is sufficient or not, ensuring the coaxiality of the insertion rod and the intermediate nut. At the same time, it is equipped with a fluid discharge channel to provide a way for excess structural adhesive and air bubbles in the connecting sleeve to be discharged, ensuring a smooth insertion process. This avoids the structural adhesive in the first connecting sleeve being rapidly squeezed and the pressure increasing suddenly during rapid insertion, which could cause uneven local force and obstruct the wedge block, preventing it from being properly positioned and thus leading to insertion failure. Attached Figure Description

[0013] Figure 1 This is an axial view of the intermediate nut described in Embodiment 1 of this utility model.

[0014] Figure 2 yes Figure 1 A cross-sectional view of JJ.

[0015] Figure 3 yes Figure 1 Enlarged view of point A.

[0016] Figure 4 This is a schematic diagram of the structure of the wedge-type mechanical joint described in this embodiment of the utility model.

[0017] Figure 5 yes Figure 4 Enlarged view of point B.

[0018] Figure 6 This is a schematic diagram of the structure of the insertion rod described in an embodiment of this utility model.

[0019] Figure 7 yes Figure 6 A bottom view.

[0020] Figure 8 yes Figure 7 HH sectional view.

[0021] Figure 9 This is a schematic diagram of the structure of the four wedges described in this embodiment of the utility model.

[0022] Figure 10 yes Figure 9A bottom view.

[0023] Figure 11 yes Figure 10 LL sectional view.

[0024] Figure 12 This is a schematic diagram of the structure of the elastic element described in an embodiment of this utility model.

[0025] Figure 13 This is a schematic diagram of the structure of the nylon washer described in an embodiment of this utility model.

[0026] Figure 14 yes Figure 13 A bottom view.

[0027] Figure 15 yes Figure 14 MM sectional view.

[0028] Figure 16 This is a schematic diagram of the structure of the first connecting sleeve according to an embodiment of the present utility model.

[0029] Figure 17 yes Figure 16 Top view.

[0030] Figure 18 yes Figure 17 GG cross-sectional view.

[0031] Figure 19 This is a schematic diagram of the structure of the second connecting sleeve according to an embodiment of the present utility model.

[0032] Figure 20 yes Figure 19 Top view.

[0033] Figure 21 yes Figure 20 FF sectional view.

[0034] Figure 22 This is a schematic diagram of the axial view of the intermediate nut described in Embodiment 2 of this utility model.

[0035] Figure 23 This is a schematic diagram of the axial view of the intermediate nut described in Embodiment 3 of this utility model.

[0036] Figure 24 This is a planar unfolded schematic diagram of the inner guide segment described in Embodiment 3 of this utility model. Detailed Implementation

[0037] Example 1

[0038] like Figure 1 and Figure 2As shown, an intermediate nut 4 for a mechanical connector includes a nut body 40 with external threads. The nut body 40 has an internal channel for a probe 3 to pass through. One end of the nut body 40 has a first conical surface 43, and the inner side of the other end of the nut body 40 has a second conical surface 41. The first conical surface 43 is used to receive the insertion of the probe 3 and guide the probe 3 into the nut body 40. An inner guide section 42 is provided between the first conical surface 43 and the second conical surface 41. The inner guide section 42 can slide with the probe 3 during the insertion process to constrain the radial movement of the probe 3 and guide the probe 3 to move axially. The nut body 40 has a fluid discharge channel 44 for fluid discharge during the insertion process of the probe 3. In this embodiment, the inner guide section 42 is a cylindrical surface that mates with the insertion rod 3, and the fluid discharge channel 44 is a groove provided on the cylindrical surface. The groove is designed to provide a discharge channel for excess structural adhesive and air bubbles in the connecting sleeve, ensuring a smooth insertion process and preventing the structural adhesive in the first connecting sleeve from being rapidly squeezed and the pressure from increasing sharply during rapid insertion, which could lead to uneven local force, obstruction of the wedge block, and failure to properly position the wedge, thus causing insertion failure.

[0039] In a preferred embodiment, the inner wall of the nut body 40 is provided with three or more grooves, which are evenly distributed circumferentially along the inner wall of the nut body 40 and extend axially along the nut body. More preferably, the inner wall of the nut body 40 is provided with six or more grooves. In this embodiment, the inner wall of the nut body 40 is provided with ten grooves evenly distributed circumferentially. The grooves can also be used to rotate and install the positioning nut 4 using tools during the assembly process.

[0040] The cone angle of the first conical surface 43 is 60-90 degrees, preferably 80 degrees, and the cone angle of the second conical surface 41 is 40-70 degrees, preferably 55 degrees. A cylindrical positioning surface 46 is provided on the outer side of the first conical surface 43, which is beneficial for guiding and positioning the insertion rod during insertion. The cylindrical positioning surface 46 forms a flange that protrudes axially from the end face of the nut body 40, which can serve as a support to position the two insertion parts of the mechanical connector.

[0041] The following description, in conjunction with the application scenario of the intermediate nut 4 described in this embodiment, will illustrate this further. For example... Figures 4 to 21As shown, a wedge-type mechanical joint includes a insertion rod 3, an intermediate nut 4, and a first connecting sleeve 1. The intermediate nut 4 is threadedly fixed inside the first connecting sleeve 1. The first connecting sleeve 1 has a first connecting portion 11 for connecting with a reinforcing bar. The first connecting sleeve 1 has two or more wedges 5 and an elastic element 6 that can apply elastic force to the wedges 5. The inner wall of the intermediate nut 4 has a second conical surface 41. The insertion rod 3 can penetrate into the space between two or more wedges 5, and the wedges 5 enter the space between the second conical surface 41 and the insertion rod 3 under the elastic force of the elastic element 6. During this process, the wedge 5 flips over, causing its wedged end to move closer to the insert rod 3, forming two circumferential line contacts between the wedge 5 and the insert rod 3, and simultaneously forming one circumferential line contact with the second conical surface 41. This allows the insert rod 3 to secure the wedge 5 between itself and the second conical surface 41, thereby securing the insert rod 3 to the intermediate nut 4. For the two circumferential line contacts between the wedge and the insert rod, the diameter of the contact line closer to the insert rod end is larger than the diameter of the other contact line, and the line connecting the three contact lines on the cross-section passing through the central axis of the wedge forms a triangle. The interior angles of this triangle at the two line contacts between the wedge and the insert rod are all acute angles. In this embodiment, the wedged end of the wedge 5 refers to the end that receives the insert rod 3 upon insertion, and is also the end that first enters the space between the insert rod 3 and the intermediate nut 4.

[0042] As a preferred embodiment, the wedge 5 is provided with an outer surface 51, an inner conical surface 52, and an outer conical surface 53. The end of the wedge 5 that receives the insertion of the rod 3, i.e., the wedge-in end, is provided with a first guide conical surface 54 for guiding the rod 3. The taper of the outer conical surface 53 is greater than the taper of the inner conical surface 52, making the wedge 5 a wedge-shaped structure with one thinner end and one thicker end. The thinner end is the wedge-in end. The rod 3 includes a threaded connection end 31, an end head 32, and a connecting section 33 between the threaded connection end 31 and the end head 32. At the connection between the end head 32 and the connecting section 33, the diameter of the end head is larger than that of the connecting section 33. The diameter forms an end edge 34 protruding from the connecting section 33. The insertion rod 3 can penetrate into the space between two or more wedges 5. Under the elastic force of the elastic member 6, the wedges 5 enter the space between the second conical surface 41 and the insertion rod 3 and flip, causing the wedge end to move closer to the connecting section 33 and form a line contact with the connecting section 33. In the insertion state, the end edge 34 is in line contact with the inner conical surface 52. The connection between the inner conical surface 52 and the first guide conical surface 54 is in line contact with the connecting section 33. The connection between the outer conical surface 53 and the outer side surface 51 is in line contact with the second conical surface 41.

[0043] As a preferred embodiment, the corners of the end edge 34, the angle between the inner conical surface 52 and the first guide conical surface 54, and the angle between the outer conical surface 53 and the outer side surface 51 are all obtuse angles, preferably 120 degrees. Setting these angles to obtuse angles ensures that the line contacts of the three-line support structure are all obtuse angle contacts. Under high pressure, the deformation is smaller, and a stable line contact engagement structure can be achieved with minimal deformation, forming a mechanical interlock between the insert, wedge, and intermediate nut. This also prevents further deformation under tensile force, enhancing the stability of the connection. In this embodiment, the end face of the end 32 facing the connecting section 33 is a conical surface, and the intersection of the conical surface and the side surface of the end forms an obtuse angle at the end edge 34. The intersection of the first guide cone surface 54 and the inner cone surface 52 is a rounded corner structure, which reduces the friction between the insertion rod 3 and the wedge block 5 during insertion, making the insertion smoother and preventing the wedge block from getting stuck. At the same time, it ensures that the intersection of the first guide cone surface 54 and the inner cone surface 52 can form a line contact with the insertion rod.

[0044] As a preferred embodiment, on a cross-section coplanar with the central axis of wedge 5, the triangle formed by the lines connecting the three contact points is a right-angled triangle or an obtuse-angled triangle, such as... Figure 2 As shown, the angle between the triangle and the second conical surface 41 is a right angle or an obtuse angle. In the connected state, the angle α between the outer conical surface 53 and the second conical surface 41 is 0.01-5 degrees. This achieves line contact while retaining the guiding effect of the second conical surface 41 on the wedge 5, preventing the wedge 5 from getting stuck during insertion and ensuring a high success rate. In this embodiment, the mechanical joint includes four wedges 5, taking into account both connection stability and tolerance space in case of insufficient insertion. In this embodiment, the wedge 5 has two-line contact with the insertion rod 3 and one-line contact with the positioning nut 4, forming a three-line support structure. Under the elastic force of the elastic element 6, the wedge 5 is tilted relative to the central axis of the mechanical joint. Pre-pressure is generated at the three line contact points, causing the wedge 5 to buckle and deform. The force is concentrated in the small area of ​​the line contact, generating extremely high local pressure (pressure P = F / A; when the force F is constant, the smaller the contact area A, the greater the pressure P). The high pressure causes the material in the contact area to undergo slight elastic or plastic deformation, which microscopically promotes the interlocking of surface rough peaks, forming a "mechanical interlocking" effect. This interlocking significantly increases the sliding resistance, preventing the wedge 5 from slipping and avoiding connection failure caused by the wedge 5 being squeezed out. This solves the problem of instability caused by pressure dispersion and local low pressure leading to slippage in the interfacial contact of the insertion structure in the prior art.

[0045] Based on the anti-slip characteristics of this embodiment, the entire mechanical joint possesses excellent structural integrity. For precast concrete components, especially precast concrete piles such as PHC pipe piles, during construction or when the pile is subjected to horizontal forces such as wind loads, seismic forces, or earth pressure, it needs to withstand enormous impact forces. This places extremely high demands on the combination of strength and toughness of the materials. A qualified elongation rate is crucial to avoid sudden changes in rigidity and to ensure that the steel bar (and thus the entire pipe pile) does not experience brittle fracture during construction. As the mechanical joint connecting the steel bar and the entire pile, it also needs to possess a qualified elongation rate. According to the "JGJ107-2016 Technical Specification for Mechanical Connection of Reinforcing Steel Bars," the total elongation rate of a Class I mechanical joint under maximum force must meet A... sgt ≥6.0%. Due to the excellent structural integrity of the mechanical joint in this embodiment, by selecting suitable materials and HRC hardness, a mechanical joint that meets the aforementioned ductility requirements can be obtained. Moreover, it can have a positive impact on pile disturbance by improving stiffness distribution and ductility, and is especially suitable for engineering scenarios with high requirements for deformation coordination and seismic performance.

[0046] As a preferred embodiment, the connecting section 33 includes a neck 35 and a guide section 36 arranged sequentially from the end 32 to the threaded connection end 31. The neck 35 is in line contact with the wedge block 5. The guide section 36 is cylindrical with a diameter larger than that of the neck 35. The inner wall of the intermediate nut 4 is provided with an inner guide section 42 that mates with the guide section 36. In this embodiment, the inner guide section 42 is also cylindrical, with a diameter slightly larger than that of the guide section 36. The insertion end of the insertion rod 3 of the intermediate nut 4 is provided with a tapered first tapered surface 43. The conical first conical surface 43 cooperates with the cylindrical inner guide section 42 to form a funnel-shaped internal space, providing greater tolerance for the insertion of the insertion rod 3. In this embodiment, the diameter of the end edge 34 is the same as the diameter of the guide section 36, and the axial distance from the end edge 34 to the guide section 36 is less than the axial length of the inner guide section 42. Thus, during the insertion process, the end edge 34 enters the inner guide section 42 first, and the inner guide section 42 guides the insertion rod 3 radially through the end edge 34. Before the end edge 34 leaves the inner guide section 42... The guide section 36 enters the inner guide section 42. The inner guide section 42 guides the insertion rod 3 through the end edge 34 and the guide section 36, preventing the insertion rod 3 from radially shifting or swaying. Subsequently, the end edge 34 passes through the inner guide section 42, which continues to guide the insertion rod 3 through the guide section 36. This ensures that the insertion rod 3 is guided by the inner guide section 42 throughout the entire insertion process. With high coaxiality with the positioning nut 4, the wedge block 5 is opened, preventing insertion failure caused by radial shifting or swaying of the insertion rod 3 leading to difficulty in rebounding of some wedge blocks 5. Simultaneously, it ensures that the insertion rod 3 and the intermediate nut 4 maintain consistent coaxiality regardless of the degree of insertion, preventing a situation where the coaxiality decreases with insufficient insertion.

[0047] As a preferred embodiment, the connection between the threaded connection end 31 and the guide section 36 is a rounded corner structure to ensure the strength of the connection and avoid stress concentration. The connection between the second guide section 36 and the rounded corner structure is a prism-shaped clamping section 37, which facilitates clamping and turning during assembly.

[0048] As a preferred embodiment, the first connecting part 11 is an inward flange that can confine the upset head of the reinforcing bar 7 within the first connecting sleeve 1. The elastic element 6 is a tower-shaped spring. The small-diameter end of the tower-shaped spring directly or indirectly abuts against the upset head of the reinforcing bar 7, preventing insufficient contact or spring overturning due to the size of the upset head. The large-diameter end of the tower-shaped spring directly or indirectly abuts against the wedge block 5. In this embodiment, the large-diameter end of the tower-shaped spring abuts against the wedge block 5 through a nylon washer 8. The nylon washer 8 is also provided with a radial positioning ring 81, and the large-diameter end of the tower-shaped spring is fitted onto the radial positioning ring 81. In the pre-installation assembly state, that is, when the intermediate nut 4 and the wedge block 5 are installed in the first connecting sleeve 1, the tower-shaped spring is preferably in a compressed state to ensure that the wedge block 5 abuts against the intermediate nut 4 evenly.

[0049] As a preferred embodiment, the inner diameter of the nylon gasket 8 is larger than the inner diameter of the wedge end face 55 when fully inserted. The gasket end face 82 of the nylon gasket 8 that abuts against the wedge is a radially concave conical surface, so that the position where the elastic element 6 applies force to the wedge 5 is located at the outer edge of the wedge end face 55, so that the wedge 5 has a tendency to flip outward, which enhances the stability of the three-line support structure and improves the reliability of the connection.

[0050] As a preferred embodiment, the wedge-type mechanical joint further includes a second connecting sleeve 2. The threaded connection end 31 of the insertion rod 3 is connected to the second connecting sleeve 2 via threads. The second connecting sleeve is provided with a second connecting part 21 for connecting with a reinforcing bar. The second connecting part is an inward flange that can confine the upset head of the reinforcing bar within the second connecting sleeve. In this embodiment, the outer surfaces of the first connecting sleeve 1 and the second connecting sleeve are prismatic structures, which facilitates assembly and rotation, and enhances the gripping force between the two sleeves and the concrete.

[0051] Example 2

[0052] like Figure 22 As shown, the difference between this embodiment and Embodiment 1 is that the inner guide section 42 is a prismatic surface, and the fluid discharge channel 44 is the edge of the prismatic surface. The diameter of the inscribed circle of the prismatic surface is slightly larger than the diameter of the guide section 36 of the insert rod 3. During the insertion of the insert rod, a gap is formed between the edge and the insert rod 3, which serves as the fluid discharge channel 44. The other structures and beneficial effects of this embodiment are the same as those of Embodiment 1, and will not be repeated here.

[0053] Example 3

[0054] like Figure 23 and Figure 24As shown, the difference between this embodiment and Embodiment 1 is that the inner guide section 42 includes an array of protrusions 47 disposed on the inner wall of the nut body 40. The tops of the array of protrusions 47 are located on the same cylindrical surface, the diameter of which is slightly larger than the diameter of the guide section 36 of the insert rod 3. The fluid discharge channel 44 is the gap between the array of protrusions, and the fluid discharge channel 44 has an interlaced mesh structure. Other structures and beneficial effects of this embodiment are the same as those of Embodiment 1, and will not be repeated here.

[0055] The embodiments described above are merely preferred embodiments of the present utility model and are not intended to limit the scope of the present utility model. Various modifications and improvements made to the technical solutions of the present utility model by those skilled in the art without departing from the spirit of the present utility model should fall within the protection scope defined by the claims of the present utility model.

Claims

1. An intermediate nut for a mechanical connector, comprising a nut body with external threads, wherein the nut body has an internal channel for a insertion rod to pass through, characterized in that: One end of the nut body is provided with a first conical surface, and the inner side of the other end of the nut body is provided with a second conical surface. An inner guide section is provided between the first conical surface and the second conical surface. The inner guide section can slide and cooperate with the insertion rod during the insertion process to constrain the radial movement of the insertion rod and guide the insertion rod to move axially. The nut body is provided with a fluid discharge channel for fluid discharge during the insertion process.

2. The intermediate nut for a mechanical joint according to claim 1, characterized in that: The inner guide section is a cylindrical surface that mates with the insert rod, and the fluid discharge channel is a groove provided on the cylindrical surface, the groove extending from the first conical surface to the second conical surface.

3. The intermediate nut for a mechanical joint according to claim 1, characterized in that: The inner wall of the nut body is provided with three or more grooves, which are evenly distributed along the circumference of the inner wall of the nut body, and the grooves are arranged along the axial direction of the nut body.

4. The intermediate nut for a mechanical joint according to claim 3, characterized in that: The inner wall of the nut body has more than six grooves.

5. The intermediate nut for a mechanical joint according to claim 1, characterized in that: The inner guide section is a prismatic surface, and the fluid discharge channel is the edge of the prismatic surface.

6. The intermediate nut for a mechanical joint according to claim 1, characterized in that: The inner guide section includes an array of protrusions disposed on the inner wall of the nut body, the tops of the array of protrusions being located on the same cylindrical surface, and the fluid discharge channel being the gap between the array of protrusions.

7. The intermediate nut for a mechanical joint according to any one of claims 1 to 6, characterized in that: The cone angle of the first conical surface is 60-90 degrees, the cone angle of the second conical surface is 40-70 degrees, and a cylindrical positioning surface is provided on the outer side of the first conical surface.

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