Anti-rotation inverted-cone-shaped steel bar connecting sleeve and construction method thereof

Abstract

The invention discloses an anti-rotation inverted-cone-shaped steel bar connecting sleeve, and relates to the technical field of steel bar connection in building structures. A multifunctional hole groove is formed in the end part of the sleeve, a protective plug or a quick release head is mounted on the multifunctional hole groove, and the multifunctional hole groove is used for performing threaded positioning on a connected reinforcing steel bar, realizing quick mounting, clamping and reinforcing the protective plug, providing a drawing clamping position for the quick release head and positioning the orientation of the connected reinforcing steel bar; and the anti-drawing platform is used for resisting drawing force and torsional force.

Description

Technical Field

[0001] This invention relates to the field of steel bar connection technology in building structures, specifically to an anti-rotation inverted conical steel bar connection sleeve and its construction method. Background Technology

[0002] With the rapid development of industrialized construction, prefabricated buildings have been widely used in modern construction projects due to their advantages such as high construction efficiency, controllable quality, and minimal environmental impact. In prefabricated concrete structures, the steel reinforcement connection between precast components is a key link in achieving structural integrity, and its connection performance directly affects the structure's load-bearing capacity, stiffness, and seismic performance.

[0003] In prefabricated structures, steel reinforcement connections primarily utilize mechanical connection technology, with steel reinforcement sleeves being one of the most widely used components. Traditional steel reinforcement sleeves mainly fall into two categories: grouting sleeves and threaded sleeves. Grouting sleeves achieve steel reinforcement connections by injecting high-strength grout. While reliable, they suffer from drawbacks such as complex processes, long curing times, significant quality dependence on construction conditions, and the inability to perform real-time quality inspection. Threaded sleeves achieve connections through the engagement of internal and external threads, offering convenient construction, but some technical bottlenecks have also emerged in practical applications:

[0004] The anchoring performance of traditional threaded sleeves in concrete needs improvement. Many sleeves rely mainly on surface friction or simple annular protrusions to resist pull-out forces, with insufficient consideration for torsional resistance. When the structure is subjected to complex loads (especially repeated loads under seismic action), the interface between the sleeve and the concrete is prone to slippage or rotation, leading to degradation of the connection stiffness and affecting the overall structural performance.

[0005] The protection of sleeves during the production, transportation, and on-site installation of precast components presents significant challenges. During concrete pouring, cement slurry can easily enter the sleeve, causing blockage of the internal threads and preventing the smooth insertion of reinforcing bars, severely impacting construction progress and quality. Although some products use plastic sleeves for protection, their sealing performance is poor, they are easily damaged, and they require manual removal before construction, increasing the risk of procedures being completed and foreign objects falling in.

[0006] The existing sleeves have a relatively limited function. During the pre-embedding stage, there is a lack of an effective positioning and guiding mechanism, making it difficult to accurately control the final orientation of the connecting steel bars. After the connection is completed, there is a lack of convenient and non-destructive quality inspection interfaces. Moreover, the existing protective plugs are simply inserted into the end face of the sleeve, which poses a risk of detachment during milling. Furthermore, it is difficult to directly verify the anchorage quality between the sleeve and the concrete, leaving potential hidden dangers for the project.

[0007] To address the above issues, there is an urgent need for an anti-rotation inverted conical rebar connecting sleeve and its construction method. Summary of the Invention

[0008] Technical problems to be solved To address the shortcomings of existing technologies, this invention provides an anti-rotation inverted conical rebar connecting sleeve and its construction method, solving the problem of the limited functionality of existing sleeves. Specifically, the lack of an effective positioning and guiding mechanism during the pre-embedding stage makes it difficult to accurately control the final orientation of the connecting rebars; after connection, the lack of a convenient and non-destructive quality inspection interface, and the existing protective plugs, which are simply inserted onto the end face of the sleeve, pose a risk of detachment during milling, and make it difficult to directly verify the anchorage quality between the sleeve and the concrete, leaving potential hidden dangers for the project.

[0009] Technical solution To achieve the above objectives, the present invention provides the following technical solution: an anti-rotation inverted conical rebar connecting sleeve, comprising: a sleeve and a pull-out platform, wherein at least one pull-out platform is fixedly connected to the outer wall of the sleeve, the sleeve has an internal thread, and a multi-functional slot is provided at the end of the sleeve. A protective plug or a quick-release head is installed on the multi-functional slot. The multi-functional slot is used for threaded positioning of the connected rebar to achieve quick installation, for clamping and reinforcing the protective plug, for providing a pull-out locking position for the quick-release head, and for positioning the orientation of the connected rebar; the pull-out platform is used to resist pull-out force and torsional force.

[0010] Preferredly, the multi-functional slot includes a recessed oblique hole at the end of the sleeve, a straight hole at the bottom of the recessed oblique hole, the inner wall of the straight hole being coaxially in contact with the external thread of the reinforcing bar, a rhomboid hole at the bottom of the straight hole, the inner wall of the rhomboid hole being arranged in a side V-shaped structure, and the rhomboid hole penetrating the internal thread of the sleeve; a straight slot penetrating the recessed oblique hole, the straight hole and the rhomboid hole is provided at the end of the sleeve.

[0011] Furthermore, the bottom of the protective plug is provided with an insert head that is fitted into the recessed oblique hole, the straight hole and the diamond hole. The protective plug and the insert head are made of elastic material, and the outer wall of the insert head is fixedly connected with a rib that is embedded half of the straight groove.

[0012] Furthermore, the quick-release head includes a pull rod that is sleeved with a straight hole. The bottom of the outer wall of the pull rod is provided with two clips, the width of which is equal to the width of the straight groove, and the clips are engaged with the inner wall of the diamond-shaped hole.

[0013] Preferably, the tensile support is an inverted conical ring structure consisting of an upper plane, an upper inclined plane, and a lower inclined plane; the upper plane forms the top plane of the inverted conical ring structure; the lower inclined plane forms the inclined plane of the inverted conical ring structure; and the upper inclined plane is an inclined connecting surface fixedly connected between the upper plane and the lower inclined plane.

[0014] Furthermore, the angle between the upper inclined surface and the sleeve axis is set to 20° to 35°; the angle between the lower inclined surface and the sleeve axis is set to 45° to 60°.

[0015] Furthermore, the upper and lower inclined surfaces of the tensile testing platform are provided with at least two vertically downward cutting slits, and a locking groove is provided on the upper inclined surface.

[0016] Furthermore, the tensile testing platform is set up in 2 to 3 layers.

[0017] Furthermore, the tensile testing platforms located at both ends of the sleeve are symmetrically arranged.

[0018] A construction method for an anti-rotation inverted conical rebar connecting sleeve includes the following steps: S1: Precast component production and sleeve pre-embedding; S1.1: Sleeve preparation: Provide anti-rotation inverted conical steel bar connecting sleeves, check the integrity of the sleeve internal thread and the multi-functional hole groove at the end, the multi-functional hole groove includes a diamond hole, a straight hole and a concave inclined hole connected in sequence, as well as a through straight groove; S1.2: Install the protective plug: Align the insert head of the protective plug with the multi-functional slot at the end of the sleeve and press it in, so that the ribs on the insert head are embedded in the straight groove until the protective plug fits against the end face of the sleeve to achieve a seal. S1.3: Fixing and Casting: Fix the sleeve with the protective plug installed in the precast component mold at the designed position with its axis perpendicular to the mold surface. At the same time, predict the orientation of the steel bars to be connected after tightening by using the orientation of the straight groove. Control the orientation of the steel bars to be connected by the direction of the straight groove to ensure that the multi-layer tensile resistance platform on the outer wall of the sleeve and the cut on it can be fully wrapped by concrete. Then pour concrete to fill the cut of the tensile resistance platform and the space in the straight groove that is not occupied by the ribs, forming a torsion-resistant concrete pin. S1.4: Curing and Transportation: After the components are poured, they shall be cured. After the curing period, the precast components with sleeves can be transported to the construction site. S2: On-site steel reinforcement connection and installation; S2.1: Site preparation: After hoisting the precast component containing the steel bars to be connected to the design position, remove the protective plug at the end of the sleeve embedded in the fixed component, and use cleaning tools to remove any debris that may exist inside the sleeve; S2.2: Rebar alignment and initial insertion: Align the exposed ends of the upper component with the center of the sleeve embedded in the lower component, insert the rebar into the multi-functional slot, and use the inner wall of the straight hole to radially position and guide the external thread of the rebar. S2.3: Tightening and fixing: Rotate the upper component or use a tool to rotate the reinforcing bar so that it can be smoothly screwed into the internal thread of the sleeve until the torque required by the design is reached, thus completing the connection of the reinforcing bars between the two precast components; S3: Connection node quality inspection; S3.1: Install quick-release head: If a tensile strength test is required, insert the pull rod of the quick-release head into the multi-functional slot of the sleeve, ensuring that the two clips at the bottom are aligned and pass through the space reserved by the rib in the straight slot; S3.2: Locking the quick-release head: Push the quick-release head to the bottom and rotate it 90 degrees so that the locking head engages with the inner wall of the V-shape on the side of the diamond-shaped hole; S3.3: Conduct the test: Clamp the pull-out force tester onto the pull-out rod and apply the pull-out force according to the prescribed procedure to test the anchorage strength between the sleeve and the concrete; S3.4: Disassembling the quick-release head: After the inspection is completed, unload the tension, rotate the quick-release head 90 degrees in the opposite direction, and remove it after the chuck is re-aligned with the straight groove.

[0019] Beneficial effects The present invention has the following beneficial effects: (1) This invention achieves synergistic enhancement of tensile and torsional resistance through the multi-layered pull-out platform and its unique inverted conical ring structure set on the outer wall of the sleeve. This changes the traditional situation where sleeves in concrete mainly rely on friction and are prone to pull-out or rotation. The composite inclined surface design consisting of the upper plane, upper inclined surface, and lower inclined surface can effectively decompose and transfer the pull-out and torsional forces to the concrete. The upper inclined surface optimizes the distribution of torsional stress, while the lower inclined surface maximizes the bearing and locking effect of the lower concrete. The cuts set on the upper and lower inclined surfaces increase the overall torsional resistance.

[0020] (2) This invention achieves integrated protection, guidance, positioning, and detection functions through the multi-functional slot design integrated at the end. It overcomes the shortcomings of existing sleeves that have single functions and require additional accessories or complex operations. The stepped structure of diamond-shaped holes, straight holes, and concave inclined holes, combined with the through straight slot, allows the slot to achieve rapid guidance and precise positioning by coaxially contacting the inner wall of the straight hole with the rebar thread, enabling quick installation. It also provides a locking point for the protective plug to achieve sealing protection of the internal thread, and provides a pull-out locking point for the quick-release head to perform anchorage strength testing. In particular, the existence of the straight slot not only provides an installation path for the ribs of the protective plug and the locking head of the quick-release head, but can also be used to predict and adjust the final orientation of the connected rebar by controlling its orientation during the pre-embedding stage, achieving high construction accuracy and wide adaptability.

[0021] (3) This invention achieves convenient protection and efficient testing of the sleeve throughout its entire life cycle through the modular use of the protective plug and quick-release head. It changes the problem of easy blockage inside the sleeve and difficulty in subsequent testing in traditional construction. The protective plug is made of elastic material, and the ribs on its insert head can be embedded in the straight groove and achieve a tight snap-fit ​​using the side V-shaped structure of the diamond hole, effectively preventing the intrusion of slurry during concrete pouring. The design of the ribs also cleverly reserves insertion space for the quick-release head. The snap-fit ​​head can be inserted through the straight groove and rotated to lock into the inner wall of the diamond hole, providing a stable force point for pull-out testing.

[0022] (4) This invention maximizes stress distribution and safety redundancy through a symmetrically arranged multi-layered pull-out platform structure. It changes the stress concentration problem that may be caused by single-layer or asymmetrical structures. The multi-layered design disperses the huge pull-out force to concrete areas at different depths, forming multiple lines of defense and effectively avoiding conical damage to the concrete. The pull-out platforms at both ends of the sleeve are symmetrically arranged, so that the sleeve is subjected to balanced forces in the concrete without directional requirements, reducing the complexity of the operation during pre-embedding and avoiding errors caused by incorrect orientation. It is particularly suitable for complex engineering scenarios with uncertain bidirectional forces or requiring rapid installation, achieving the effect of strong versatility and high safety reserves.

[0023] (5) This invention achieves high precision and efficiency in prefabricated building construction by standardizing and integrating the processes of sleeve pre-embedding, rebar connection, and quality inspection. From sleeve preparation, protective plug installation, and pre-embedding to control the rebar orientation using straight grooves, to rapid alignment and tightening of the rebar on site, and convenient installation of quick-release heads for pull-out testing when needed, a complete and verifiable high-quality connection solution is formed. The method has clear steps and is interconnected, effectively ensuring the reliability of the final connection node and the safety of the overall structure, and promoting the standardized construction of prefabricated buildings.

[0024] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0025] Figure 1 This is an isometric view of the entire invention. Figure 2 This is an isometric view of the sleeve of the present invention; Figure 3 This is a front view of the entire invention; Figure 4 This is a top view of the entire invention.

[0026] Figure 5 This is a top view of the sleeve of the present invention.

[0027] Figure 6 This is a cross-sectional view of the entire invention.

[0028] Figure 7 This is a cross-sectional view of the sleeve of the present invention.

[0029] Figure 8 This is a partial schematic diagram of the tensile resistance table of the present invention.

[0030] Figure 9 This is an isometric view of the quick-release head of the present invention.

[0031] Figure 10 This is a front view of the quick-release head of the present invention.

[0032] Figure 11 This is an isometric view of the protective plug of the present invention.

[0033] Figure 12 This is a front view of the protective plug of the present invention.

[0034] Reference numerals: Sleeve 1, Pull-out platform 2, Upper plane 21, Upper inclined plane 22, Lower inclined plane 23, Locking groove 24, Cutout 25, Multifunctional slot 3, Recessed inclined hole 31, Straight hole 32, Diamond hole 33, Straight groove 34, Protective plug 4, Insert head 41, Rib 42, Quick release head 5, Pull rod 51, Clip head 52. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] Please see Figures 1-12 This invention provides a technical solution: an anti-rotation inverted conical rebar connecting sleeve, comprising: a sleeve 1 and a tensile support 2, wherein at least one tensile support 2 is fixedly connected to the outer wall of the sleeve 1, and the sleeve 1 has internal threads. The end of the sleeve 1 is provided with a multi-functional slot 3. A protective plug 4 or a quick-release head 5 is installed on the multi-functional slot 3. The multi-functional slot 3 is used for thread positioning of the connected steel bars to achieve quick installation, for clamping and reinforcing the protective plug 4, for providing a pull-out position for the quick-release head 5, and for positioning the orientation of the connected steel bars. The tensile resistance table 2 is used to resist tensile force and torsional force.

[0037] When sleeve 1 connects two steel bars, one steel bar is connected first and the concrete is poured before connecting the other steel bar. At least one end of sleeve 1 is a multi-functional slot 3.

[0038] Both steel bars are connected after the concrete is poured, and both ends are multi-functional slotted holes 3.

[0039] When sleeve 1 is connected to a steel bar, one end of sleeve 1 is sealed and the other end is a multi-functional slot 3.

[0040] It can orient and position pre-installed steel bars, perform pull-out testing or removal, increase resistance to rotation and pull-out, reinforce the protective plug 4, and perform threaded positioning of steel bars.

[0041] In practical implementation, in prefabricated buildings, the reinforcing bars of precast wall panels or columns need to be precisely aligned with the reinforcing bars of adjacent components. The usage process of this sleeve is as follows: First, sleeve 1 is pre-embedded in the concrete of the first precast component (such as the base slab). At this time, the multi-layered pull-out support 2 fixed on the outer wall of sleeve 1 is tightly wrapped by the concrete. After the concrete solidifies, the inverted conical structure of the pull-out support 2 can provide a huge force to effectively resist the force (pull-out force) that pulls sleeve 1 out of the concrete. At the same time, its shoulder structure can also resist the tendency of the sleeve to rotate in the concrete (torsional force). The second precast component (such as a wall panel) is hoisted on the construction site, and its exposed reinforcing bars are aligned and screwed into the internal thread of the pre-embedded sleeve 1, thus completing the reinforcing bar connection between the two components. The whole process is efficient and the connection strength is high.

[0042] Preferred, Reference Figure 2 The multi-functional slot 3 includes a recessed inclined hole 31 at the end of the sleeve 1, a straight hole 32 at the bottom of the recessed inclined hole 31, the inner wall of the straight hole 32 is coaxially in contact with the external thread of the reinforcing bar, and a rhomboid hole 33 at the bottom of the straight hole 32. The inner wall of the rhomboid hole 33 is set in a side V-shaped structure, and the rhomboid hole 33 passes through the internal thread of the sleeve 1. The sleeve 1 has a straight groove 34 at its end, which is formed by a through-hole 31, a straight hole 32 and a diamond-shaped hole 33.

[0043] In practical implementation, taking the multi-functional slot 3 at the top of sleeve 1 (i.e., the end where the rebar is screwed in) as an example: when connecting rebar, the operator first inserts the end of the rebar into the multi-functional slot 3. The inner wall of the straight hole 32 at the bottom of the slot is coaxial with the external thread of the rebar, which can initially guide and radially position the rebar, ensuring that the rebar is screwed in smoothly and achieving "quick installation". If there are burrs or slight deviations at the end of the rebar, the side V-shaped inner wall of the diamond hole 33 can play a guiding and fault-tolerant role. During the sleeve pre-embedding stage, the recessed inclined hole 31 and the straight slot 34 provide a basis for the snap-fit ​​and positioning of the protective plug 4 or the quick-release head 5. For example, during factory pre-embedding, the protective plug 4 can be pressed in, and its elastic material will deform and be clamped through the straight slot 34 to prevent concrete from pouring into the sleeve. When pull-out testing or special disassembly is required, quick-release head 5 can be installed. Its clip 52 can be inserted through the straight groove 34 and rotated to lock under the V-shaped wall of the diamond hole 33, providing a force point. At the same time, the orientation of the straight groove 34 can also predict the orientation of the connecting steel bar after tightening during the pre-embedding process.

[0044] The direction of the internal thread of sleeve 1 and the direction of the straight groove 34 are fixed. After the reinforcing bar is tightened, the orientation of the reinforcing bar and the direction of the straight groove 34 are fixed. The orientation of the reinforcing bar (L-shaped reinforcing bar) can be predicted by the direction of the straight groove 34.

[0045] Further reference Figure 1 , Figure 11 and Figure 12 The bottom of the protective plug 4 is provided with an insert head 41 that is fitted into the recessed oblique hole 31, the straight hole 32 and the diamond hole 33. The protective plug 4 and the insert head 41 are made of elastic material. The outer wall of the insert head 41 is fixedly connected with a rib 42 that is embedded in half of the straight groove 34.

[0046] In practical implementation, the protective plug 4 is mainly used for internal protection of the sleeve during transportation, storage and concrete pouring of precast components.

[0047] When the components are prefabricated in the factory, the workers align the insert head 41 of the protective plug 4 with the multi-functional slot 3 and press it in forcefully.

[0048] Since the protective plug 4 and the insert head 41 are made of elastic rubber or silicone material, the insert head 41 will undergo elastic deformation during the pressing process and pass smoothly through the straight hole 32.

[0049] When the protruding part at the bottom of the insert head 41 reaches the spacious space of the diamond hole 33, the elastic material restores its deformation and forms a tight interference fit and snap-fit ​​with the V-shaped inner wall of the diamond hole 33 and the edge of the straight groove 34, thereby firmly sealing the port of the sleeve 1.

[0050] This effectively prevents cement slurry, debris, and other contaminants from entering the internal threads of the sleeve, ensuring smooth connection of reinforcing bars on the construction site and avoiding installation failures caused by thread blockage.

[0051] The rib 42 is designed to allow concrete to fully enter the inner wall of the straight groove 34, so that only half of the concrete can enter the straight groove 34. The concrete inside the straight groove 34 can form an anti-torsion structure, providing the straight cylinder 1 with anti-torsion capacity. At the same time, the rib 42 can reserve space for the quick-release head 5's clip 52 to be inserted.

[0052] Further reference Figure 2 , Figure 9 and Figure 10 The quick-release head 5 includes a pull rod 51, which is sleeved with a straight hole 32. The bottom of the outer wall of the pull rod 51 is provided with two clips 52. The width of the clips 52 is equal to the width of the straight groove 34. The clips 52 are engaged with the inner wall of the diamond-shaped hole 33.

[0053] In practical implementation, the quick-release head 5 is mainly used for pull-out force testing of connected steel bar sleeves or for emergency disassembly under special circumstances.

[0054] When connection quality inspection is required, the operator inserts the pull rod 51 of the quick-release head 5 into the straight hole 32 and ensures that the two clips 52 at its bottom are aligned with the straight groove 34.

[0055] After pushing the quick-release head 5 all the way down, rotate it 90 degrees (or other angles, depending on the number of straight slots) so that the chuck head 52 moves from the position of the straight slot 34 to below the V-shaped bevel of the diamond hole 33.

[0056] At this point, the clamp 52 is locked by the bevel of the diamond-shaped hole 33 and cannot be pulled out directly. The tester can then clamp the jig of the pull-out testing machine onto the pull-out rod 51 and apply a pull-out force.

[0057] The force is transmitted through the clamp 52 to the robust inner wall of the diamond-shaped hole 33, and then acts on the entire sleeve 1, thereby verifying the anchorage strength between the sleeve and the concrete. After the test is completed, the quick-release head 5 is rotated in the opposite direction to realign the clamp 52 with the straight groove 34, allowing it to be easily removed.

[0058] Preferred, Reference Figures 1 to 8 The tensile support 2 is an inverted conical ring structure consisting of an upper plane 21, an upper inclined plane 22, and a lower inclined plane 23; The upper plane 21 forms the top plane of the inverted conical ring structure; The lower inclined surface 23 forms the inclined surface of the inverted conical ring structure; The upper inclined surface 22 is an inclined connecting surface that is fixedly connected between the upper plane 21 and the lower inclined surface 23.

[0059] In practical implementation, the inverted conical ring structure of the pull-out platform 2 is the core of its pull-out and rotation resistance performance. Taking a single-layer pull-out platform 2 as an example: its upper plane 21 forms a horizontal bearing surface during concrete pouring, directly bearing the upward pull-out force. The lower inclined plane 23 forms a large angle of 45° to 60° with the sleeve axis, forming a steep inclined plane, mainly providing strong pull-out resistance. The upper inclined plane 22, located between the two, has a smaller angle with the axis (20° to 35°), forming a relatively gentle transition surface. Firstly, it can provide better stress distribution when bearing torsional force, effectively decomposing and transferring the torsional force to the concrete; secondly, when the sleeve is pressed into the mold for positioning, this inclined plane is easier to guide and position. This multi-angle composite inclined plane design, compared with a single conical surface, can more effectively cope with complex multi-directional stress states.

[0060] Further reference Figure 8 The angle between the upper inclined surface 22 and the axis of the sleeve 1 is set to 20° to 35°; The angle between the lower inclined surface 23 and the axis of the sleeve 1 is set to 45° to 60°.

[0061] In practical implementation, the included angle of the inclined plane of the tensile support platform 2 has been optimized.

[0062] Setting the angle between the upper inclined surface 22 and the axis of the sleeve 1 to 20° to 35° (e.g., 30°) is to achieve the best balance between torsional and tensile resistance.

[0063] If the angle is too small, the slope will be too gentle, resulting in insufficient tensile strength; if the angle is too large, it will be close to vertical, weakening the torsional resistance.

[0064] The inclined plane at this angle can generate a sufficient horizontal component force to resist the rotational torque. The angle between the lower inclined plane 23 and the axis of the sleeve 1 is set to 45° to 60° (e.g., 55°) to maximize its pull-out resistance.

[0065] The normal force and friction of the concrete on the inclined plane together form a huge mechanical lock, preventing the sleeve from being pulled out.

[0066] Further reference Figure 4 and Figure 5 The upper inclined surface 22 and lower inclined surface 23 of the tensile resistance table 2 are provided with at least two vertically downward cutting notches 25, as shown in the reference. Figures 6 to 8 A locking groove 24 is provided on the upper inclined surface 22.

[0067] In specific implementation, at least two (usually four are symmetrically arranged) vertical cuts 25 are provided on the upper inclined surface 22 and the lower inclined surface 23 of the tensile platform 2. A locking groove 24 is provided on the upper inclined surface 22. After the concrete enters the locking groove 24, it will form a ring-shaped anti-rotation and anti-pull-out structure.

[0068] When precast components are poured with concrete, the concrete flows into these cuts under pressure and forms "concrete pins" after solidification. These pins greatly enhance the tensile strength of the sleeve against torsion and prevent any slight rotation of the sleeve within the concrete.

[0069] Further reference Figure 2 The tensile testing platform 2 is set up with 2 to 3 layers.

[0070] In practice, the tensile support platform 2 can be set up in 2 to 3 layers.

[0071] For critical connection parts that bear large tensile forces (such as shear wall connections in high-rise buildings), a three-layer tensile support platform will be used.

[0072] The multi-layered design creates multiple lines of defense, distributing the enormous pull-out force to concrete areas at different depths, thus preventing stress from being concentrated in one place and potentially causing cone-shaped failure of the concrete.

[0073] Each layer of tensile support works independently while sharing the load, greatly improving the safety redundancy and reliability of the connection.

[0074] For components with general load-bearing requirements, setting two layers is sufficient to meet the needs, balancing economy and safety.

[0075] Furthermore, the tensile support platforms 2 located at both ends of the sleeve 1 are symmetrically arranged.

[0076] In practice, the tensile support platforms 2 located at both ends of the sleeve 1 are symmetrically arranged.

[0077] The symmetrical design makes sleeve 1 a system with balanced forces in the concrete. Regardless of which end of the sleeve the pull-out force comes from (for example, the direction of the pull-out force may change under complex stress conditions), the pull-out resistance at both ends of the sleeve is exactly the same.

[0078] During the prefabrication process, the symmetrical design also eliminates the directional requirements of the sleeve. Workers do not need to distinguish between up, down, left, and right when pre-embedding, and can directly place it into the mold, which effectively reduces the complexity of operation, avoids pre-embedding errors caused by incorrect orientation, and improves construction efficiency.

[0079] A construction method for an anti-rotation inverted conical rebar connecting sleeve, characterized by the following steps: S1: Precast component production and sleeve pre-embedding; S1.1: Sleeve preparation: Provide anti-rotation inverted conical steel bar connecting sleeve, check the integrity of the internal thread of sleeve 1 and the multi-functional slot 3 at the end, the multi-functional slot 3 includes a diamond-shaped hole 33, a straight hole 32 and a recessed oblique hole 31 connected in sequence, and a through straight slot 34. S1.2: Install the protective plug: Align the insert head 41 of the protective plug 4 with the multi-functional slot 3 at the end of the sleeve 1 and press it in so that the rib 42 on the insert head 41 is embedded in the straight slot 34 until the protective plug 4 fits against the end face of the sleeve 1 to achieve a seal. S1.3: Fixing and Pouring: The sleeve 1 with the protective plug 4 installed is fixed in the designed position of the precast component mold with its axis perpendicular to the mold surface. At the same time, the orientation of the straight groove 34 is used to predict the orientation of the steel bar to be connected after tightening. The orientation of the steel bar to be connected is controlled by the direction of the straight groove 34 to ensure that the multi-layer tensile resistance platform 2 on the outer wall of the sleeve 1 and the cut 25 thereon are fully wrapped by concrete. Then, concrete is poured. The concrete fills the cut 25 of the tensile resistance platform 2 and the space in the straight groove 34 that is not occupied by the rib 42, forming a torsion-resistant concrete pin. S1.4: Curing and Transportation: After the components are poured, they shall be cured. After the curing period is over, the precast components with sleeve 1 can be transported to the construction site. S2: On-site steel reinforcement connection and installation; S2.1: Site preparation: After hoisting the precast component containing the steel bars to be connected to the design position, remove the protective plug 4 at the end of the sleeve 1 embedded in the fixed component, and use cleaning tools to remove any debris that may exist inside the sleeve 1; S2.2: Rebar alignment and initial insertion: Align the exposed ends of the upper component with the center of the sleeve 1 embedded in the lower component, insert the rebar into the multi-functional slot 3, and use the inner wall of the straight hole 32 to radially position and guide the external thread of the rebar. S2.3: Tightening and fixing: Rotate the upper component or use a tool to rotate the reinforcing bar so that it can be smoothly screwed into the internal thread of sleeve 1 until the torque required by the design is reached, thus completing the connection of the reinforcing bars between the two precast components; S3: Connection node quality inspection; S3.1: Install quick-release head: If a pull-out test is required, insert the pull rod 51 of quick-release head 5 into the multi-functional slot 3 of sleeve 1, ensuring that the two clips 52 at the bottom are aligned and pass through the space reserved by rib 42 in straight slot 34. S3.2: Locking the quick-release head: Push the quick-release head 5 to the bottom and rotate it 90 degrees so that the locking head 52 is engaged with the inner wall of the side V-shape of the diamond hole 33; S3.3: Conduct the test: Clamp the pull-out force tester on the pull-out rod 51 and apply the pull-out force according to the prescribed procedure to test the anchorage strength between the sleeve 1 and the concrete. S3.4: Disassembling the quick-release head: After the inspection is completed, unload the tension, rotate the quick-release head 5 in the opposite direction by 90 degrees, so that the chuck 52 is re-aligned with the straight groove 34 and then removed.

[0080] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0081] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A rotation-resistant inverted conical steel bar connecting sleeve, comprising: A sleeve (1) and a tensile support (2), wherein at least one tensile support (2) is fixedly connected to the outer wall of the sleeve (1), and the sleeve (1) has an internal thread, characterized in that: The sleeve (1) has a multi-functional slot (3) at its end. A protective plug (4) or a quick-release head (5) is installed on the multi-functional slot (3). The multi-functional slot (3) is used to thread the connected steel bars to achieve quick installation, to clamp and reinforce the protective plug (4), to provide a pull-out position for the quick-release head (5), and to position the orientation of the connected steel bars. The tensile resistance table (2) is used to resist tensile force and torsional force.

2. The anti-rotation inverted conical rebar connecting sleeve according to claim 1, characterized in that: The multifunctional slot (3) includes a recessed oblique hole (31) opened at the end of the sleeve (1), a straight hole (32) opened at the bottom of the recessed oblique hole (31), the inner wall of the straight hole (32) is coaxially in contact with the external thread of the reinforcing bar, a rhomboid hole (33) opened at the bottom of the straight hole (32), the inner wall of the rhomboid hole (33) is set in a side V-shaped structure, and the rhomboid hole (33) passes through the internal thread of the sleeve (1); The sleeve (1) has a straight groove (34) at its end, which passes through a concave inclined hole (31), a straight hole (32) and a rhomboid hole (33).

3. The anti-rotation inverted conical rebar connecting sleeve according to claim 2, characterized in that: The bottom of the protective plug (4) is provided with an insert head (41) that is fitted into the recessed oblique hole (31), the straight hole (32) and the diamond hole (33). The protective plug (4) and the insert head (41) are made of elastic material. The outer wall of the insert head (41) is fixedly connected with a rib (42) that is embedded in half of the straight groove (34).

4. The anti-rotation inverted conical rebar connecting sleeve according to claim 2, characterized in that: The quick-release head (5) includes a pull rod (51), which is sleeved with a straight hole (32). The bottom of the outer wall of the pull rod (51) is provided with two clips (52). The width of the clips (52) is equal to the width of the straight groove (34). The clips (52) are engaged with the inner wall of the diamond hole (33).

5. A rotation-resistant inverted conical rebar connecting sleeve according to any one of claims 1 to 4, characterized in that: The tensile resistance platform (2) is an inverted conical ring structure consisting of an upper plane (21), an upper inclined plane (22) and a lower inclined plane (23); The upper plane (21) forms the top plane of the inverted conical ring structure; The lower inclined surface (23) forms the inclined surface of the inverted conical ring structure; The upper inclined surface (22) is an inclined connecting surface that is fixedly connected between the upper plane (21) and the lower inclined surface (23).

6. The anti-rotation inverted conical rebar connecting sleeve according to claim 5, characterized in that: The angle between the upper inclined surface (22) and the axis of the sleeve (1) is set to 20° to 35°; The angle between the lower inclined surface (23) and the axis of the sleeve (1) is set to 45° to 60°.

7. The anti-rotation inverted conical rebar connecting sleeve according to claim 5, characterized in that: The upper inclined surface (22) and lower inclined surface (23) of the anti-pull table (2) are provided with at least two vertically downward cutting cuts (25), and a locking groove (24) is provided on the upper inclined surface (22).

8. The anti-rotation inverted conical rebar connecting sleeve according to claim 5, characterized in that: The tensile support (2) is provided in 2 to 3 layers.

9. The anti-rotation inverted conical rebar connecting sleeve according to claim 8, characterized in that: The tensile support platforms (2) located at both ends of the sleeve (1) are symmetrically arranged.

10. A construction method for an anti-rotation inverted conical rebar connecting sleeve, characterized in that: Includes the following steps: S1: Precast component production and sleeve pre-embedding; S1.1: Sleeve preparation: Provide the anti-rotation inverted conical steel bar connecting sleeve, check the integrity of the internal thread and end multi-functional slot (3) of the sleeve (1), the multi-functional slot (3) includes a diamond-shaped hole (33), a straight hole (32) and a concave inclined hole (31) connected in sequence, and a through straight slot (34). S1.2: Install the protective plug: Press the insert head (41) of the protective plug (4) into the multi-functional slot (3) at the end of the sleeve (1), so that the rib (42) on the insert head (41) is embedded in the straight groove (34) until the protective plug (4) is in contact with the end face of the sleeve (1) to achieve a seal; S1.3: Fixing and pouring: The sleeve (1) with the protective plug (4) installed is fixed in the design position of the precast component mold with its axis perpendicular to the mold surface. At the same time, the orientation of the straight groove (34) is used to predict the orientation of the steel bar to be connected after tightening. The orientation of the steel bar to be connected is controlled by the direction of the straight groove (34) to ensure that the multi-layer tensile resistance platform (2) on the outer wall of the sleeve (1) and the cut (25) thereon can be fully wrapped by concrete. Then, concrete is poured. The concrete fills the space in the cut (25) of the tensile resistance platform (2) and the straight groove (34) that is not occupied by the rib (42) to form a torsion-resistant concrete pin. S1.4: Curing and transportation: After the components are poured, they are cured. After the curing period, the precast components with sleeves (1) can be transported to the construction site. S2: On-site steel reinforcement connection and installation; S2.1: Site preparation: After hoisting the precast component containing the steel bars to be connected to the design position, remove the protective plug (4) at the end of the sleeve (1) embedded in the fixed component, and use cleaning tools to remove any debris that may exist inside the sleeve (1); S2.2: Rebar alignment and initial introduction: Align the exposed ends of the upper component with the center of the sleeve (1) pre-embedded in the lower component, insert the rebar into the multi-functional slot (3), and use the inner wall of the straight hole (32) to radially position and guide the external thread of the rebar; S2.3: Tighten and fix: Rotate the upper component or use a tool to rotate the steel bar so that it can be smoothly screwed into the internal thread of the sleeve (1) until the torque required by the design is reached, and the steel bar connection between the two prefabricated components is completed; S3: Connection node quality inspection; S3.1: Install quick-release head: If a pull-out test is required, insert the pull rod (51) of the quick-release head (5) into the multi-functional slot (3) of the sleeve (1), and ensure that the two clips (52) at the bottom are aligned and pass through the space reserved by the rib (42) in the straight slot (34); S3.2: Locking the quick release head: Push the quick release head (5) to the bottom and rotate it 90 degrees so that the clip (52) is engaged with the side V-shaped inner wall of the diamond hole (33); S3.3: Conduct the test: clamp the fixture of the pull-out force test equipment onto the pull-out rod (51) and apply the pull-out force according to the prescribed procedure to test the anchorage strength between the sleeve (1) and the concrete; S3.4: Disassembling the quick-release head: After the test is completed, unload the tension, rotate the quick-release head (5) 90 degrees in the opposite direction, and then remove the chuck (52) after it is aligned with the straight groove (34).

Images