High-pulling-resistance steel bar connecting sleeve

Abstract

The invention discloses a high-pulling-resistance reinforcing steel bar connecting sleeve which comprises a sleeve body, and the sleeve body comprises a lower pulling-resistance positive frustum section, a vertical section and an upper inverted cone section which are sequentially and integrally connected from bottom to top and are each of a cylindrical structure. And the outer surfaces of the lower anti-pulling regular frustum section, the vertical section and the upper inverted cone section jointly form a concave surface shaped like a Chinese character'yi '. Through the unique concave surface design shaped like a Chinese character'Ya ', especially optimization of key parameters such as L1 / K, L2 / L3 and L2 / L4, and coupling of appropriate parameters such as L1 and D1, the sleeve and concrete form reliable mechanical engagement. The structure of the anti-pulling positive frustum stage at the bottom is similar to the anti-pulling mechanism of threads, the pulling-out force can be effectively transmitted to concrete with a larger volume, concrete cracking caused by stress concentration is avoided, and therefore the pulling-out force is obviously improved to 90 kN or above.

Description

Technical Field

[0001] The present invention relates to the technical field of building steel bar connection, and particularly relates to an embedded steel bar connection sleeve used in the concrete surface layer of railway tunnels or bridges, especially a steel bar connection sleeve with a high anti-pulling performance having a "sub - shaped" surface structure. Background Art

[0002] In the process of building industrialization, steel bar connection sleeves are widely used in the steel bar connection between precast concrete components. The bond strength (anti - pulling force) between traditional steel bar connection sleeves and concrete is limited, usually not exceeding 80 kN. Especially under specific working conditions, such as pouring concrete first and then burying the sleeve (post - embedding method), and when the top of the sleeve is flush with the concrete surface (i.e., the embedding depth is equal to the sleeve length), the anti - pulling force of ordinary sleeves often fails to meet the design requirements, even lower than the safety lower limit of 50 kN. <00000XXX>To solve the above problems, prior arts such as CN222614687U and CN218234022U disclose sleeves with annular grooves. However, the groove design is mostly simple annular steps, lacking systematic optimization of the groove depth and taper ratio. As a result, under the condition of shallow burial depth (such as the embedding depth is equal to the sleeve length), the concrete biting teeth are prone to shear failure, and the anti - pulling force is usually lower than 60 kN, which is difficult to meet the requirements of working conditions with extremely high fatigue load and anti - pulling performance in railways, bridges, etc., and it is impossible to achieve a good balance among material saving, construction convenience, and meeting the high anti - pulling force requirements. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies of the above - mentioned prior arts, and provide a "sub - shaped" high - anti - pulling steel bar connection sleeve. By optimizing the geometric parameters of its surface, the anti - pulling force between the sleeve and concrete is significantly improved, while taking into account the processing economy and construction convenience. <000001XXX>To achieve the above purpose, the present invention adopts the following technical solutions: <00000XXX>A high - anti - pulling steel bar connection sleeve, comprising: a sleeve body, which includes a lower anti - pulling positive frustum stage, a vertical section, and an upper inverted frustum section that are integrally connected in sequence from bottom to top and are all in a cylindrical structure; The outer surfaces of the lower anti - pulling positive frustum stage, the vertical section, and the upper inverted frustum section together form a "sub - shaped" concave surface, and the horizontal distance between the vertical section and the large end of the anti - pulling positive frustum stage is the depth K of the "sub - shaped" concave surface; The ratio of the total height L1 of the "sub - shaped" concave surface to the depth K is greater than 13 and less than 18; In the "Asian" - shaped concave surface, the ratio of the total height L2 of the lower positive frustum for uplift resistance stage and the vertical section to the height L3 of the upper inverted frustum is greater than 3 and less than 8; In the "Asian" - shaped concave surface, the ratio of the total height L2 of the lower positive frustum for uplift resistance stage and the vertical section to the height L4 of the vertical section is greater than 1 and less than 1.5.

[0007] Technical effects of the above - mentioned technical solutions: (1) Structural functional differentiation: The sleeve is decomposed into three functional sections, making the interaction mechanism between the sleeve and concrete clear. The lower positive frustum for uplift resistance stage and the vertical section are used to provide the main uplift force; the upper inverted frustum is used for guiding the embedding.

[0008] (2) Optimization of mechanical properties: 13 < L1 / K < 18: Ensure that the sleeve concave surface and the concrete咬合 teeth have the best "aspect ratio". It not only ensures that the concrete teeth have enough height (L1) to provide the bond length, but also ensures enough root width (K) to resist shear failure and avoid cutting off the concrete teeth.

[0009] 1 < L2 / L4 < 1.5: Ensure that the stress - bearing step (the lower positive frustum for uplift resistance stage) has enough axial thickness, and at the same time ensure that the root of the step is an obtuse angle, which can convert the part of the concrete under shear load into compressive load, avoiding stress concentration and the problem of difficult acute - angle processing.

[0010] (3) Improvement of construction technology: 3 < L2 / L3 < 8: Ensure that the sleeve has an inverted frustum shape with "larger at the top and smaller at the bottom" in the length direction. This shape makes the resistance small when the sleeve is inserted into the un - solidified concrete, the exhaust is smooth, which is convenient for construction workers to operate and improves the embedding efficiency and quality.

[0011] Furthermore, the total height L1 of the "Asian" - shaped concave surface is greater than 50 mm. L1 represents the total length of the Asian - shaped concave surface. Controlling the lower limit is to control the lower limit of the uplift force. If L1 is too small, the upper limit of its uplift force is not high, and then the uplift force of the sleeve will not be high.

[0012] Furthermore, the depth K of the "Asian" - shaped concave surface is greater than 2.5 mm and less than 6 mm. K represents the width of the concrete at the concave surface. If the value of K is too small, that is, the uplift step at the lower positive frustum for uplift resistance stage 12 is too small, and the concrete is too thin to play an uplift role; if the value of K is too large, the concave surface will encroach on the thread area and cause thread damage.

[0013] Further, the large end of the lower anti - uplift regular frustum stage is integrally connected to the lower inverted frustum stage. The ratio of the outer diameter D1 of the large end of the upper inverted frustum section to the outer diameter D2 of the large end of the lower inverted frustum stage is less than or equal to 1. This can ensure that the upper end diameter is at least the same as the lower end, or the upper end is smaller and the lower end is larger, in order to ensure that the width K of the concrete at the concave surface can meet the above requirements.

[0014] Further, the ratio of the outer diameter D2 of the large end of the lower inverted frustum stage to the outer diameter D3 of the small end of the lower inverted frustum stage is greater than 1. This can ensure that the lower end is an inverted conical structure, which can facilitate the embedding of the sleeve into the concrete, facilitate construction, improve the construction effect, and save construction costs.

[0015] Further, the outer diameter D1 of the large end of the upper inverted frustum section is greater than 28 mm and less than 50 mm, that is, 28 mm < D1 < 50 mm; D1 directly controls the magnitude of the anti - uplift force between the sleeve and the concrete. Just like a thick steel bar and a thin steel nail inserted into the concrete, if it is too thin, the anti - uplift force will not be high. Controlling the lower limit of D1 is to control that the upper limit of the anti - uplift force will not be too low. If D1 is too small, the upper limit of its anti - uplift force will not be high.

[0016] Further, there is at least one "Y - shaped" concave surface along the length direction of the sleeve body.

[0017] Further, it also includes a vertical extension section integrally connected to the large end of the upper inverted frustum section, and the height L5 of the vertical extension section is greater than or equal to 0 mm.

[0018] The effects of the above technical solutions: Increase structural redundancy and adaptability: This vertical extension section can be used as a "grasping section" or "adjusting section". When the sleeve needs to slightly increase the total length to adapt to different mold or burial depth requirements, this section can be lengthened to achieve this without changing the core "Y - shaped" anti - uplift structure.

[0019] Further, the height L6 of the lower inverted frustum stage is greater than or equal to 2 mm, that is, L6 ≥ 2 mm. The effects of the above technical solutions: (1) Ensure the effectiveness of guidance: L6 ≥ 2 mm ensures that the inverted cone structure at the bottom has sufficient axial length to form an effective guiding slope. If L6 is less than 2 mm, the inverted cone is too short, the taper is too gentle or even cannot be processed, and it loses the function of facilitating embedding into the concrete.

[0020] (2) Ensure the diameter difference: It provides a spatial basis for meeting D2 / D3 > 1 and ensures that the bottom closing structure can be realized.

[0021] Further, the total length L of the sleeve body is composed of the sum of L1, L5 and L6, and L is greater than or equal to 52 mm.

[0022] The effects of the above technical solution: Comprehensive performance guarantee: This length is the sum of L1 (>50), L5 (≥0), and L6 (≥2). A minimum total length is defined to ensure that, while meeting all structural characteristics (especially the length of L1), the sleeve as a whole has sufficient dimensions to accommodate the threaded and concrete engagement area, preventing insufficient thread count or inadequate concrete bond length due to an excessively short sleeve.

[0023] Chamfers are provided at the small end edge of the lower inverted cone stage and / or at the upper end edge of the vertical extension section.

[0024] The effects of the above technical solution: (1) Construction safety: Eliminate sharp metal edges and burrs to prevent workers from cutting their hands when handling and installing sleeves.

[0025] (2) Protecting concrete and formwork: When embedded in concrete or in contact with formwork, the smooth chamfered edge will not scratch the formwork surface or create additional microcrack initiation points in the concrete.

[0026] Furthermore, the inner wall of the sleeve body is provided with a threaded structure for connection with the reinforcing bar thread.

[0027] Furthermore, the thread structure is either a through-hole thread that penetrates the sleeve body or a blind-hole thread.

[0028] The effects of the above technical solution: Achieving rebar connection: The threaded structure is the core of achieving mechanical connection between two rebars, ensuring reliable force transmission between the rebar and the sleeve.

[0029] Adaptable to different working conditions: Through thread: Suitable for connecting long steel bars, where two steel bars are screwed in from both ends to connect.

[0030] Countersunk internal thread (blind hole): suitable for the situation where a half sleeve is pre-embedded in precast components, with one end connected to the reinforcing bar and the other end serving as a reserved interface.

[0031] Furthermore, the sleeve body is made of carbon steel.

[0032] The advantages of the above technical solution are: It ensures both strength and economy: Carbon steel possesses sufficient yield strength and tensile strength, enabling it to withstand enormous pull-out forces without plastic deformation or fracture. Simultaneously, carbon steel has relatively low cost and good machinability (easy to machine threads and shapes), meeting the construction industry's requirements for cost-effectiveness.

[0033] Furthermore, when the sleeve body is embedded in concrete with a strength of not less than C20 and the embedment depth is equal to the sleeve length, that is, when the top of the sleeve is flush with the concrete surface and the outer diameter D2 end is at the bottom, the pull-out force between the sleeve body and the concrete is greater than 90kN.

[0034] In summary, the beneficial effects of this invention are as follows: (1) High pull-out resistance: Through the unique “Asia” shaped concave surface design, L1 / K is limited to between 13 and 18, so that the height-to-width ratio of the concrete interlocking teeth is in the optimal range, which not only ensures sufficient interlocking height (L1>50mm), but also prevents stress concentration caused by the narrow root of the interlocking teeth, and saves costs. After analysis and experimental verification, with appropriate D1 and other parameters, the pull-out resistance in this range can stably reach more than 90kN.

[0035] (2) Convenient construction: The double inverted cone structure formed at the upper and lower ends of the sleeve (defined by L2 / L3 and D2 / D3) makes the sleeve less resistant when embedded in fresh concrete, easier to operate, improves construction efficiency and embedding accuracy, and reduces labor costs.

[0036] (3) Good economic efficiency: By precisely controlling the proportional relationship of L1 / K, L2 / L4, while ensuring high pull-out resistance, the waste of steel caused by blindly increasing the diameter or length of the sleeve is avoided, and the best balance between performance and cost is achieved. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0038] Figure 1 This is a structural schematic diagram of a high pull-out rebar connecting sleeve provided by the present invention.

[0039] Figure 2 This is a schematic diagram of a high pull-out rebar connecting sleeve pre-embedded in concrete, as provided by the present invention.

[0040] Figure 3 This invention provides a schematic diagram showing two “A”-shaped concave surfaces arranged along the length of the sleeve body. Detailed Implementation

[0041] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0042] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0043] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0044] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0045] This invention discloses a high pull-out rebar connecting sleeve, comprising: a sleeve body 1, which includes a lower pull-out truncated cone stage 12, a vertical section 13, and an upper inverted cone section 14, which are integrally connected from bottom to top and are all cylindrical in structure; The outer surfaces of the lower anti-uplift truncated cone stage 12, the vertical section 13, and the upper inverted cone section 14 together form an "Y"-shaped concave surface. The lateral distance between the vertical section 13 and the large end of the anti-uplift truncated cone stage 12 is the depth K of the "Y"-shaped concave surface. The ratio of the total height L1 to the depth K of the "Asian" - shaped concave surface is greater than 13 and less than 18, that is, 13 < (L1 / K) < 18; when the value of L1 / K is appropriate, it can ensure that the height and width of the concrete at the concave surface are large. It can also be understood that the concrete cross - section at the concave surface is a rectangle (with the length upwards), but it is not a long and narrow rectangle. In this way, the stressed concrete area is large and wide, and it is not easily split by the upward pulling force of the sleeve. In the "Asian" - shaped concave surface, the ratio of the total height L2 of the lower positive frustum of the anti - uplift stage 12 and the vertical section 13 to the height L3 of the upper inverted frustum 14 is greater than 3 and less than 8, that is, 3 < (L2 / L3) < 8; when the value of L2 / L3 is appropriate, it can ensure that the upper end is an inverted conical structure, which together with the depth represented by K forms an Asian - shaped structure. The inverted cone at the upper end of the Asian - shaped structure can facilitate the sleeve to be buried in the concrete, which is convenient for construction, improves construction effect, and saves construction cost. In the "Asian" - shaped concave surface, the ratio of the total height L2 of the lower positive frustum of the anti - uplift stage 12 and the vertical section 13 to the height L4 of the vertical section 13 is greater than 1 and less than 1.5, that is, 1 < (L2 / L4) < 1.5; the value of L2 / L4 represents that the step angle at the lower positive frustum of the anti - uplift stage 12 can only be an obtuse - angled structure, and there will be no acute angles and right angles. It is very difficult to process acute angles, and the processing cost is too high. For a right - angled structure, the concrete is subjected to pure shear load. An obtuse angle can convert the part of the shear load received by the concrete into a compressive load, which can reduce the risk of concrete shear rupture and improve the anti - uplift ability. In addition, control the obtuse angle not to be too large. If the obtuse angle is too large and close to 180 degrees, then the concave - surface cross - section will become smaller, greatly weakening the anti - uplift force.

[0046] In some embodiments, the total height L1 of the "Asian" - shaped concave surface is greater than 50 mm, that is, L1 > 50 mm. L1 represents the total length of the Asian - shaped concave surface. Controlling the lower limit is to control the lower limit of the anti - uplift force. If L1 is too small, the upper limit of its anti - uplift force will not be high, and then the anti - uplift force of the sleeve will not be high either.

[0047] In some embodiments, the depth K of the "Asian" - shaped concave surface is greater than 2.5 mm and less than 6 mm, that is, 2.5 mm < K < 6 mm; K represents the width of the concrete at the concave surface. If the value of K is too small, that is, the anti - uplift step at the lower positive frustum of the anti - uplift stage 12 is too small, and the concrete is too thin to play an anti - uplift role. If the value of K is too large, the concave surface will encroach on the thread area and cause the thread to be damaged.

[0048] In some embodiments, the large end of the lower positive frustum stage 12 is integrally connected to the lower inverted frustum stage 11. The ratio of the outer diameter D1 of the large end of the upper inverted cone section 14 to the outer diameter D2 of the large end of the lower inverted frustum stage 11 is less than or equal to 1, that is, (D1 / D2) ≤ 1, which can ensure that the upper end diameter is at least the same as the lower end, or the upper end is smaller and the lower end is larger, so as to ensure that the width K of the concrete at the concave surface can meet the above requirements.

[0049] In some embodiments, the ratio of the outer diameter D2 of the large end of the lower inverted frustum stage 11 to the outer diameter D3 of the small end of the lower inverted frustum stage 11 is greater than 1, that is, (D2 / D3) > 1, which can ensure that the lower end is an inverted conical structure, facilitating the embedding of the sleeve into the concrete, improving the construction effect and saving construction costs.

[0050] In some embodiments, the outer diameter D1 of the large end of the upper inverted cone section 14 is greater than 28 mm and less than 50 mm, that is, 28 mm < D1 < 50 mm; D1 directly controls the magnitude of the uplift force between the sleeve and the concrete, just like a thick steel bar and a thin steel nail inserted into the concrete. If it is too thin, the uplift force will not be high. Controlling the lower limit of D1 is to control that the upper limit of the uplift force will not be too low. If D1 is too small, the upper limit of its uplift force will not be high.

[0051] In some embodiments, there is at least one "sub"-shaped concave surface along the length direction of the sleeve body 1.

[0052] In some embodiments, the high anti-uplift steel bar connecting sleeve further includes a vertically extending section 15 integrally connected to the large end of the upper inverted cone section 14, and the height L5 of the vertically extending section 15 is greater than or equal to 0 mm.

[0053] In some embodiments, the height L6 of the lower inverted frustum stage 11 is greater than or equal to 2 mm. The total length L of the sleeve body 1 is composed of the sum of L1, L5 and L6, and L is greater than or equal to 52 mm.

[0054] In some embodiments, chamfers are provided at the edge of the small end of the lower inverted frustum stage 11 and / or at the edge of the upper end of the vertically extending section 15.

[0055] In some embodiments, a thread structure for threadedly connecting with the steel bar is provided on the inner wall of the sleeve body 1.

[0056] In some embodiments, the thread structure is a through-hole thread or a blind-hole thread penetrating the sleeve body 1.

[0057] In some embodiments, the material of the sleeve body 1 is carbon steel.

[0058] In some embodiments, chamfers are provided at the edge of the small end of the lower inverted frustum stage 11 and / or at the edge of the upper end of the vertically extending section 15.

[0059] In some embodiments, when the sleeve body 1 is embedded in concrete with a strength not lower than C20 and the embedding depth is equal to the sleeve length, that is, when the top of the sleeve is flush with the concrete surface, and the end with the outer diameter D2 is at the bottom, the uplift resistance between the sleeve body 1 and the concrete is greater than 90 kN.

[0060] The principle of high uplift resistance of the present invention: The "sub" - shaped concave surface engages with the concrete, and the step at the bottom (the lower uplift regular frustum stage 12) forms an effect similar to thread uplift resistance; the ratio (L1 / K) of the height L1 to the depth K of the "sub" - shaped concave surface is appropriate, which not only ensures that the depth of the concrete above the step is sufficient but also ensures that the width of the engagement between the concrete and the "sub" - shaped concave surface is sufficient. Moreover, the ratio of L2 / L4 being greater than 1 can convert the part of the concrete subjected to shear load into compressive load. Compared with the pure shear load when the ratio of L2 / L4 is equal to 1, it can reduce the risk of concrete shear rupture and improve the uplift resistance. In addition, the outer diameters D1 and D2 of the sleeve cannot be too small, otherwise, even if the depth of the concrete above the step is sufficient and the width of the engagement between the concrete and the "sub" - shaped concave surface is sufficient, it will cause stress concentration in the concrete and easy rupture, resulting in low uplift resistance.

[0061] Only by ensuring that the ratio of L1 to the depth K (L1 / K) is appropriate and the sizes of the outer diameters D1 and D2 are suitable can the strength of the concrete be fully exerted and a very high uplift strength be achieved.

[0062] In addition, the depth K of the "sub" - shaped concave surface is appropriate, and (L2 / L3) is appropriate, thus forming an inverted conical structure; in addition, (D2 / D3)>1 can also ensure that the structure below the concave surface is an inverted conical structure. The advantages of the two inverted conical structures are: it is convenient for the sleeve to be inserted into the concrete, convenient for construction, reduces the operation intensity, improves the construction efficiency, and reduces the construction cost.

[0063] Comparison table of the uplift resistance of the present invention with CN222614687U and CN218234022U:

[0064] The main difference in dimensions between Example 1 and Comparative Example 1 lies in the outer diameter. The outer diameter of Comparative Example 1 is on the small side, resulting in stress concentration in the concrete during pulling. The tensile force of Comparative Example 1 is about 45% different from that of Example 1.

[0065] The dimensional difference between Example 1 and Comparative Example 2 mainly lies in the size of the "sub" - shaped concave surface. The concave surface size (L1 / K) of Comparative Example 2 is only 4.32. The depth of the concrete above the step is insufficient, and the width of the interlocking between the concrete and the "sub" - shaped concave surface is also insufficient. Therefore, the step at the bottom of the concave surface is like a scraper and is prone to cracking the concrete around the sleeve. Although there are 4 steps, the strength of the concrete still cannot be fully exerted, resulting in a difference in the tensile resistance of Comparative Example 2 compared to Example 1 reaching about 35%.

[0066] Through the unique "sub" - shaped outer - shape design and precise limitation of its key geometric parameters, the present invention realizes the collaborative optimization in four aspects: mechanical properties, construction technology, structural safety and economic cost, and achieves remarkable overall technical effects: 1. Ultra - high pull - out resistance (core effect) The present invention fundamentally solves the technical problem of insufficient pull - out resistance of traditional sleeves under the working conditions of shallow burial depth (the burial depth is equal to the sleeve length) or low - strength concrete (such as C20).

[0067] Quantitative improvement: By decomposing the outer surface of the sleeve into the lower inverted frustum stage, the positive frustum for pull - out resistance stage, the vertical section and the upper inverted cone section, and strictly controlling the长深比 (L1 / K), the step ratio (L2 / L4) and the main body diameter of the sleeve (D1), a "mechanical locking" structure with deep embedding of concrete and the sleeve is formed.

[0068] Effect data: The measured data shows that when fully buried in C20 concrete, the pull - out resistance can reach 93 - 102 kN. Compared with the ordinary sleeves mentioned in the background technology (usually less than 80 kN) and the prior arts CN222614687U (45 - 51 kN) and CN218234022U (39 - 47 kN), the pull - out resistance of the present invention is nearly doubled or even more, and stably exceeds the industry high standard of 90 kN.

[0069] 2. Construction convenience (process effect) The present invention not only focuses on the strength after connection, but also fully considers the convenience of the construction process of burying the sleeve into the concrete.

[0070] Double - inverted - cone guiding design: By limiting the ratio of the vertical section to the upper inverted cone section (3 < L2 / L3 < 8), the diameter ratio (D2 / D3 > 1) and the height (L6≥2 mm) of the lower inverted frustum stage, smooth inverted - cone structures are formed at both the upper and lower ends of the sleeve.

[0071] Effect manifestation: This form enables the sleeve to smoothly displace the concrete slurry when inserted into the un - solidified concrete, with small resistance, easy centering and smooth air exhaust, significantly reducing the operation intensity of construction workers and improving the embedding accuracy and construction efficiency of the embedded parts.

[0072] 3. Structural Safety and Durability (Ensurance Effect) Through detail optimization, the present invention eliminates potential safety hazards and ensures the long-term stability of the structure.

[0073] Preventing stress concentration and damage: Defining L2 / L4 > 1 ensures that the connection of the anti-pulling step is an obtuse angle, avoiding the risk of stress concentration and processing cracks brought by acute angles. Defining the value of L1 / K within a reasonable range prevents the concrete engaging teeth from being damaged due to being too short (easy to be sheared) or too narrow (easy to crack).

[0074] Protecting the integrity of the thread: Strictly defining the concave depth K < 6 mm ensures that the groove processing on the outer surface does not invade and damage the internal thread area, guaranteeing the reliability of the connection between the steel bar and the sleeve.

[0075] Construction safety protection: Chamfering the edges of both ends of the sleeve eliminates metal burrs, effectively preventing construction workers from being cut, reflecting the user-friendly design.

[0076] 4. Economy and Applicability (Comprehensive Effect) While pursuing high performance, the present invention also takes into account the cost control of industrial production and market adaptability.

[0077] High material utilization rate: Through theoretical calculation and experimental verification, the optimal balance point between performance and material consumption is found (such as 28 mm < D1 < 50 mm, 13 < (L1 / K) < 18). It avoids the waste of steel caused by blindly increasing the sleeve diameter or length in pursuit of strength.

[0078] Simple and efficient structure: At least one "sub" - shaped concave surface is required, and Example 1 shows that only one concave surface can achieve the optimal performance, indicating that this design is extremely efficient and does not require complex superposition of multiple concave surfaces, simplifying the processing technology.

[0079] Strong working condition adaptability: The internal thread can choose through-hole or counterbore structure, and the material is selected as common carbon steel, making the sleeve applicable to both the connection of full-length steel bars and the embedded parts of precast components, with a wide range of applications.

[0080] In summary, through the original "sub" - shaped structure and the coupled design of its multi - dimensional geometric parameters, the present invention produces a synergistic effect: It not only achieves the breakthrough mechanical index of the anti - pulling force greater than 90 kN under harsh working conditions, but also simultaneously has the comprehensive advantages of being easy to construct, safe and reliable, and saving materials, successfully solving the industry pain point that it is difficult to balance among "high strength, easy construction, and low cost" in the existing steel bar connecting sleeves.

[0081] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0082] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A high tensile reinforcing bar connection sleeve characterised in that, Comprising: A sleeve body (1), which includes a lower anti-pulling regular frustum stage (12), a vertical section (13), and an upper inverted frustum section (14) that are integrally connected in sequence from bottom to top and are all in a cylindrical structure; The outer surfaces of the lower anti-pulling regular frustum stage (12), the vertical section (13), and the upper inverted frustum section (14) together form a "sub" - shaped concave surface, and the lateral distance between the vertical section (13) and the large end of the anti-pulling regular frustum stage (12) is the depth K of the "sub" - shaped concave surface; The ratio of the total height L1 of the "sub" - shaped concave surface to the depth K is greater than 13 and less than 18; In the "sub" - shaped concave surface, the ratio of the total height L2 of the lower anti-pulling regular frustum stage (12) and the vertical section (13) to the height L3 of the upper inverted frustum section (14) is greater than 3 and less than 8; In the "sub" - shaped concave surface, the ratio of the total height L2 of the lower anti-pulling regular frustum stage (12) and the vertical section (13) to the height L4 of the vertical section (13) is greater than 1 and less than 1.

5.

2. A high tensile reinforcing bar coupling sleeve according to claim 1, characterised in that, The total height L1 of the "sub" - shaped concave surface is greater than 50 mm.

3. The high pull-out resistance rebar connecting sleeve according to claim 1, characterized in that, The depth K of the "sub" - shaped concave surface is greater than 2.5 mm and less than 6 mm.

4. A high pull-out rebar connecting sleeve according to claim 1, characterized in that, The large end of the lower anti-pulling regular frustum stage (12) is integrally connected with a lower inverted frustum stage (11), and the ratio of the outer diameter D1 of the large end of the upper inverted frustum section (14) to the outer diameter D2 of the large end of the lower inverted frustum stage (11) is less than or equal to 1.

5. A high pull-out rebar connecting sleeve according to claim 4, characterized in that, The ratio of the outer diameter D2 of the large end of the lower inverted frustum stage (11) to the outer diameter D3 of the small end of the lower inverted frustum stage (11) is greater than 1.

6. A high pull-out rebar connecting sleeve according to claim 1, characterized in that, The outer diameter D1 of the large end of the upper inverted frustum section (14) is greater than 28 mm and less than 50 mm.

7. A high pull-out rebar connecting sleeve according to claim 1, characterized in that, There is at least one "sub" - shaped concave surface along the length direction of the sleeve body (1).

8. A high pull-out rebar connecting sleeve according to claim 4, characterized in that, It further includes a vertical extension section (15) integrally connected to the large end of the upper inverted frustum section (14), and the height L5 of the vertical extension section (15) is greater than or equal to 0 mm.

9. A high pull-out rebar connecting sleeve according to claim 8, characterized in that, The height L6 of the lower inverted frustum stage (11) is greater than or equal to 2 mm, the total length L of the sleeve body (1) is composed of the sum of L1, L5, and L6, and L is greater than or equal to 52 mm.

10. A high pull-out rebar connecting sleeve according to claim 8, characterized in that, Chamfers are provided at the edge of the small end of the lower inverted frustum stage (11) and / or at the edge of the upper end of the vertical extension section (15).

Images