EPS wall module connecting structure for house building

Abstract

The present application relates to a kind of EPS wall module connecting structure for housing construction, including square steel tube, wallboard, through-flow plate, connecting piece and cross rib pull ring, square steel tube includes center column, connecting plate and multiple side columns, both outer walls of side column front and back are arranged with through-flow plate, the outer wall of through-flow plate is arranged with wallboard, side column, through-flow plate and wallboard are fixedly connected together by connecting piece, so that square steel tube and wallboard form pouring space;The section of through-flow plate is concave-convex surface, concave-convex surface forms the through-flow groove of intercommunication pouring space and other wall module;The side wall of wallboard is provided with the tongue and groove of connecting other wall module;Cross rib pull ring is set on the outer wall opposite connecting plate on side column.The present application relates to the technical field of building structure engineering, solve the destructive demolition of traditional EPS wallboard in the process of reconstruction and expansion, layout adjustment difficulty, wallboard connection is not reusable and other problems, realize flexible, adjustable wallboard reorganization structure, save time and material, improve engineering efficiency.

Description

Technical Field

[0001] This invention relates to the field of building structure engineering technology, and specifically to an EPS wall module connection structure for building construction. Background Technology

[0002] EPS is a polystyrene polymer. The finished product is a rigid, closed-cell foam plastic that is lightweight and durable. It has been widely used in the construction industry as an ideal building material. With social progress, EPS has been processed into EPS wall modules, which has become a widely promoted model for self-built houses in rural areas. This is a composite wall panel self-built house with polystyrene foam cavity boards as the inner and outer insulation layers of the house walls, and reinforced concrete load-bearing layers poured into the cavities. No formwork removal is required. The wall modules adopt a tongue-and-groove connection method, which has the advantages of quick installation, integrated casting, light weight, and good thermal insulation performance.

[0003] Once the internal concrete of an EPS modular building is poured, the wall panels form a monolithic structure. While this construction method is indeed robust and stable, it also presents challenges and limitations during renovations and expansions involving wall panel reassembly. After pouring, the wall panels are an integrated structure. Due to the tongue-and-groove connection method of the wall modules, disassembling the wall panels can easily cause large-scale damage to the EPS wall panels. It's difficult to ensure the integrity of the disassembly by maintaining the joints. Furthermore, the horizontal reinforcing bars are tied to the longitudinal reinforcing bars in the columns, making them difficult to remove after pouring, often affecting the columns and causing damage to their structure. Additionally, the one-time connection method of the tongue-and-groove joints and horizontal reinforcing bars means that new connectors or other methods must be used to fix the wall panels during reconstruction. This not only increases material and labor costs but also causes further damage to the existing wall panels, beams, and columns when using connectors to fix them.

[0004] Once EPS modular wall structures are completed, expanding or altering the wall panels often requires rebuilding the entire structure, which is significantly more inconvenient and incurs additional costs compared to traditional brick walls. In reality, rural housing construction frequently involves renovations and expansions, and disaster-prone areas also face the challenge of repairing damaged walls. Therefore, when using EPS modular construction, the possibility of repairs and expansions must be carefully considered. Incorporating a detachable wall structure in the design to accommodate potential renovations and expansions can greatly simplify wall panel replacement.

[0005] Therefore, it is necessary to study an EPS wall module connection structure for building construction. Summary of the Invention

[0006] Therefore, the purpose of this invention is to provide an EPS wall module connection structure for building construction, which solves the problems of destructive demolition, difficult layout adjustment, and non-reusable wall panel connections in the process of renovation and expansion of traditional EPS wall panels. It realizes a flexible and adjustable wall panel reconfiguration structure, saves time and materials, and improves engineering efficiency.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] An EPS wall module connection structure for building construction includes a square steel tube, wall panels, flow plates, connectors, and horizontal reinforcing rings. The square steel tube includes a central column, a connecting plate, and multiple side columns. Both the central column and the side columns are hollow columns and are fixedly connected by the connecting plate. Flow plates are arranged on the front and rear outer walls of the side columns, and wall panels are arranged on the outer walls of the flow plates. The connectors are long bolt kits. The side columns, flow plates, and wall panels are all provided with corresponding through holes and are fixedly connected together by the connectors, forming a casting space between the square steel tube and the wall panels. Connecting sleeves are fitted onto the connectors at the casting space locations. The cross-section of the flow plate is concave and convex, forming a flow channel connecting the casting space and other wall modules.

[0009] The sidewall of the wall panel is provided with tongue and groove joints for connecting other wall modules;

[0010] A horizontal reinforcing ring is provided on the outer wall of the side column opposite to the connecting plate.

[0011] Furthermore, the cross-sectional shape of the square steel tube includes L-shaped, T-shaped and cross-shaped, the wall panel is the corresponding L-shaped plate or straight plate, and multiple sets of the flow plate and the horizontal rib pull ring are provided.

[0012] Furthermore, the transverse rib pull ring includes a stud and a pull ring. A threaded hole is opened on the outer wall of the side post opposite to the connecting plate. One end of the stud is threadedly connected to the threaded hole, and the other end is threadedly connected to the pull ring.

[0013] Furthermore, the transverse rib pull ring includes a stud and a pull ring. A connecting seat is fixed on the outer wall of the side post opposite to the connecting plate. The connecting seat has a threaded hole. One end of the stud is threadedly connected to the threaded hole, and the other end is threadedly connected to the pull ring.

[0014] Furthermore, the stud is fitted with a quick-release sleeve.

[0015] Furthermore, sealing rings are provided between the connecting sleeve and the side column, and between the quick-release sleeve and the side column or connecting seat.

[0016] Furthermore, the outer wall of the wall panel is provided with a groove for accommodating the outer end of the connector, and a sealing plate is provided on the outer end face of the groove.

[0017] Furthermore, the square steel tube includes an upper column and a lower column, the flow plate extends upward and forms an outer positioning area, and the upper column and the lower column are respectively fixed to the flow plate by high-strength bolt kits.

[0018] Furthermore, a positioning sleeve is slidably fitted between the side columns of the upper and lower columns to form an inner positioning area, and the positioning sleeve is a through square steel tube structure.

[0019] The beneficial effects of the above technical solution are:

[0020] (1) This invention, based on a detachable and reconfigurable wall structure using square steel tubes, brings several beneficial effects to the renovation and expansion of EPS wall module buildings. First, by using square steel tubes as the main structure of the wall, higher strength and stability are provided, enhancing the overall load-bearing capacity and seismic performance of the wall. Second, the design of the square steel tubes makes the wall connection more flexible, allowing for easy reconfiguration and layout adjustments to adapt to different spatial needs and functional layouts. This flexibility makes the design and use of the building more sustainable and adaptable. In addition, this invention simplifies the wall dismantling and reconstruction process, reducing labor and time costs and significantly reducing material waste. This innovative design also has environmental advantages, as the reusable and adjustable wall structure reduces the generation of construction waste. In summary, this invention provides a detachable and reconfigurable wall system, bringing greater flexibility, efficiency, and sustainability, and providing significant benefits for renovation and expansion projects.

[0021] (2) The square steel pipe of this invention, as a supporting element of the wall structure, can bear and disperse the tensile force of the connectors, effectively reducing the stress on the EPS material, thereby improving the stability and reliability of the wall connection. The introduction of the square steel pipe solves the stress concentration problem of connectors such as tie bolts and long bolts, enabling the application of tie bolts and long bolts in EPS wall modules. This directly improves the wall's resistance to external impacts during pouring and mitigates the problem of wall detachment. This connection method also provides more flexible possibilities for wall reorganization and adjustment. By disassembling the connectors, wall panels can be removed quickly, effectively, and precisely, avoiding large-scale damage caused by forced demolition. This brings greater flexibility, efficiency, and sustainability, providing significant benefits for renovation and expansion projects.

[0022] (3) The design of the connecting sleeve of the present invention ensures that the connecting parts are not affected by the concrete pouring, so that the connecting parts can always retain the function of disassembly. When the wall is reassembled, the wall panel can be quickly removed by disassembling the connecting parts, which facilitates the disassembly and reassembly process of the wall.

[0023] (4) The concave and convex design of the flow plate of the present invention can not only provide flow channels, so that the pouring space inside the column can be connected with the pouring area of ​​other external walls, thus making the pouring integrated, but also reduce the contact area between concrete and wall panel, reduce the bonding strength between wall panel and concrete block, and reduce the difficulty of wall panel removal. The wall panel is fixedly connected mainly through connectors, which will not increase the probability of wall panel falling off, which is beneficial to the work of disassembling wall panel during wall reconstruction.

[0024] (5) The present invention adopts the design of horizontal rib pull ring, so that the horizontal rib is tied to the pull ring. When dismantling, the pull ring can be quickly dismantled by breaking the wall and digging out the quick-release sleeve, and then by turning the knob to quickly release the stud protected by the sleeve, without affecting the threaded hole on the side column or the connecting seat. When reassembling, only the new horizontal rib pull ring needs to be reinstalled to realize the arrangement of the horizontal rib, which facilitates the reassembly of the wall and improves the stability of the reassembled wall.

[0025] (6) The present invention provides a connection method between columns. A connecting sleeve is fitted between the side columns of the upper and lower columns. When installing the upper column, the connecting sleeve is first fitted and fixed in the side column of the lower column to form an inner positioning area. Then the upper column is installed on the lower column through the inner and outer positioning areas. This can ensure effective alignment between the upper and lower columns, simplify the alignment process, and greatly improve the installation accuracy and efficiency. Attached Figure Description

[0026] Figure 1 This is a three-dimensional schematic diagram of the present invention;

[0027] Figure 2 This is a front view schematic diagram of the present invention;

[0028] Figure 3 for Figure 2 Top view;

[0029] Figure 4 A three-dimensional schematic diagram of another implementation method;

[0030] Figure 5 for Figure 4 Top view;

[0031] Figure 6 A three-dimensional schematic diagram of another implementation method;

[0032] Figure 7 This is a schematic diagram illustrating another implementation of the connecting sleeve;

[0033] Figure 8 This is a cross-sectional view of the horizontal rib tie ring;

[0034] Figure 9 This is a cross-sectional view of the connection node between the upper and lower columns.

[0035] Attached reference numerals: 1 is square steel pipe, 2 is wall panel, 3 is flow plate, 4 is connector, 5 is horizontal rib pull ring, 6 is casting space, 7 is connecting sleeve, 8 is quick-release sleeve, 9 is sealing ring, 10 is connecting seat, 101 is center column, 102 is side column, 103 is connecting plate, 104 is lower column, 105 is upper column, 106 is positioning sleeve, 201 is groove, 202 is sealing plate, 203 is tongue and groove, 301 is flow groove, 501 is pull ring, 502 is stud. Detailed Implementation

[0036] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0037] Example 1: This example aims to provide an EPS wall module connection structure for building construction. It is mainly used for the column part of EPS wall modules, and provides a detachable structure for wall reconstruction work such as maintenance, expansion and renovation. It addresses the problems of destructive demolition, difficult layout adjustment and non-reusable wall panel connection in the process of traditional EPS wall panels during reconstruction and expansion. It realizes a flexible and adjustable wall panel reconstruction structure, saving time and materials and improving project efficiency.

[0038] An EPS wall module connection structure for building construction, such as Figure 1 The structure includes a square steel tube 1, a wall panel 2, a flow plate 3, connectors 4, and horizontal reinforcing rings 5. The square steel tube 1 is a commonly used square steel tube structure in concrete engineering, including a central column 101, a connecting plate 103, and multiple side columns 102. Both the central column 101 and the side columns 102 are hollow columns, and they are fixedly connected by the connecting plate 103. The type of square steel tube 1 is not limited to a single-plate connection type, and the type of connecting plate 103 is not limited to a single plate, but also includes laced type, perforated single-plate type, non-perforated single-plate type, ribbed double-plate type, non-ribbed double-plate type, etc. This embodiment adopts the non-ribbed double-plate type. The cross-sectional shape of the square steel tube 1 includes L-shaped, T-shaped, and cross-shaped, which can be selected according to the requirements of the wall. This embodiment proposes an implementation method of an L-shaped square steel tube 1. Square steel pipe 1 serves as a column, replacing longitudinal reinforcement or longitudinal steel cage when installing EPS wall modules. In this embodiment, considering cost, it is not fully deployed throughout the building. According to the design, it is only deployed in wall areas where reconfigurable structures need to be reserved, while other areas still use conventional EPS wall module construction.

[0039] Both the front and rear outer walls of the side column 102 are equipped with flow plates 3, and the outer walls of the flow plates 3 are equipped with wall panels 2. The connector 4 uses a long bolt kit. The side column 102, flow plates 3, and wall panels 2 each have corresponding through holes. The connector 4 passes through these through holes to fix the side column 102, flow plates 3, and wall panels 2 together, forming a casting space 6 between the square steel pipe 1 and the wall panel 2. To facilitate the disassembly of the connector 4 during wall reconstruction, such as… Figure 2 The connector 4 is fitted with a connecting sleeve 7 at the pouring space 6. The connecting sleeve 7 is made of a corrosion-resistant plastic material that is not easy to stick to the concrete. The cross-section of the flow plate 3 is concave and convex, which forms a flow channel 301 connecting the pouring space 6 and other wall modules. In addition, the concave and convex surface effectively reduces the contact area between the wall panel 2 and the concrete, making it easier to disassemble the wall panel 2 during wall reconstruction.

[0040] In this embodiment, the connector 4 is designed to allow for the detachable removal of the wall panel 2. During wall reconstruction, the wall panel 2 can be easily removed by disassembling the connector 4, preventing large-scale damage to the wall modules. The connector 4 is used to fix the two wall panels 2. During the pouring of the pouring space 6, the connector 4 provides tension to prevent the two wall panels 2 from bursting due to concrete pressure, similar to traditional wall formwork pouring. While the connector 4 can indeed use tie bolts, the traditional process cannot be directly applied to EPS walls because EPS material cannot directly withstand the stress of tie bolts. However, in this embodiment, by embedding a square steel pipe 1 inside the wall panel 2, the tension of the tie bolts can be transferred to the square steel pipe 1 instead of being directly applied to the wall panel 2. The square steel pipe 1 has high strength and rigidity, effectively absorbing and dispersing tension, providing a more reliable connection and support. The introduction of square steel pipe 1 solves the stress concentration problem of connectors 4 such as tie bolts and long bolts, enabling their application in EPS wall modules. This directly improves the wall's resistance to external impacts during casting. After casting, connectors 4 are not removed, providing continuous fixation to wall panel 2 and effectively preventing it from detaching. However, this embodiment requires high-quality EPS material. It is best to place connectors 4 at the contact point between the flow plate 3 and wall panel 2 to avoid gaps in the wall panel 2 corresponding to the stress application point of the long bolt assembly. Additionally, buffer plates or large washers should be fitted to the long bolt heads to further reduce stress concentration and damage to wall panel 2. In this embodiment, wall panel 2 is made of EPS material, but higher-strength materials such as concrete slabs can also be used. However, the sidewalls of wall panel 2 should be equipped with tongue and groove joints 203 for connecting other wall modules. Wall panel 2 consists of L-shaped and straight plates corresponding to square steel pipe 1.

[0041] like Figure 3A threaded hole is formed on the outer wall of the side column 102 opposite to the connecting plate 103. A horizontal reinforcement pull ring 5 is installed in the threaded hole. The horizontal reinforcement pull ring 5 includes a stud 502 and a pull ring 501. One end of the stud 502 is threaded to the threaded hole, and the other end is threaded to the pull ring 501. The horizontal reinforcement pull ring 5 is used to tie the horizontal reinforcement. During wall reconstruction, the horizontal reinforcement pull ring 5 is dug out. By removing the horizontal reinforcement pull ring 5 and installing a new horizontal reinforcement pull ring 5, the horizontal reinforcement can be quickly rearranged, avoiding excessive damage to the column when removing the horizontal reinforcement, and improving the structural stability when retying the horizontal reinforcement, thus improving construction quality and efficiency. However, this also means that the threaded hole needs to be sealed to prevent the impact of concrete pouring. A quick-release sleeve 8 is fitted between the horizontal reinforcement pull ring 5 and the side column 102, and a sealing ring 9 is placed between the sleeve and the side wall.

[0042] To ensure that the assembly and disassembly of the connector 4 and the horizontal reinforcing ring 5 are not affected by the pouring process, in this embodiment, the pouring is only carried out in the gap between the wall panel 2 and the square steel pipe 1, i.e., the pouring space 6. The square steel pipe 1 needs to be kept hollow to ensure the effectiveness of the threads. In addition, the surface of the connection part between the connector 4 and the horizontal reinforcing ring 5 is coated with an anti-stick coating.

[0043] Example 2 is basically the same as Example 1, except that the square steel pipe 1 in this example is a cross-shaped square steel pipe 1, and the exposed part of the connector 4 outside the wall is optimized. This example further describes the structure.

[0044] like Figure 4 In this embodiment, the wall panel 2 is designed based on the L-shaped shape of the square steel pipe 1. In this embodiment, it is mainly used as a central support column, which can connect the four walls, such as... Figure 5 The connecting plate 103 of the square steel pipe 1 uses a single-plate connection, which provides a larger pouring space 6, increasing the stability and integration after pouring. Four sets of horizontal reinforcing rings 5 ​​are still vertically arranged. Depending on the design, more or fewer horizontal reinforcing rings 5 ​​can be used. In this embodiment, considering the appearance quality of the wall panel 2 and the needs of subsequent plastering, a groove 201 is provided on the outer wall of the wall panel 2 to accommodate the outer end of the connector 4. A sealing plate 202 is screwed to the outer end face of the groove 201. However, the connection method of the sealing plate 202 is not limited to screw connection; low-temperature spot welding, high-strength bonding, nesting fit, and detachable snap-fit ​​connection can all be achieved, aiming to achieve detachable sealing of the groove 201. Considering the material and wall thickness of the wall panel 2, the depth of the groove 201 should not be too deep. This is why long bolts are used instead of tie bolts. If tie bolts are intended to be used, they can be removed after pouring and replaced with long bolts with relatively smaller bolt heads to maintain the continuous fit of the wall panel 2 and prevent detachment.

[0045] Example 3 is basically the same as Example 1, except that the square steel pipe 1 is T-shaped and is cast inside the square steel pipe 1. The structure of the connector 4 and the horizontal reinforcing ring 5 is optimized to realize the casting inside the square steel pipe 1, and a connection structure to realize column-to-column connection is proposed. This example further describes the structure.

[0046] The internal casting of square steel tube 1 will greatly improve the stability of the structure, such as Figure 7 For this connector 4 set, the connecting sleeve 7 is changed to an integrated structure that runs through the side column 102, the two side wall panels 2, and the two side flow plates 3. This requires pre-drilling holes in the side column 102. The entire set of square steel pipe 1, wall panel 2 and flow plate 3 can be industrially customized, or holes can be drilled on-site to flexibly meet the requirements. This design avoids the impact of the concrete poured inside the square steel pipe 1 on the connector 4 and ensures the detachability of the connector 4.

[0047] like Figure 8 The horizontal rib pull ring 5 includes a stud 502 and a pull ring. In practice, the stud 502 can also be a continuous bolt. A connecting seat 10 is fixed on the outer wall of the side post 102 opposite to the connecting plate 103. The connecting seat 10 has a threaded hole. One end of the stud 502 is threaded into the threaded hole, and the other end is threaded into the pull ring. The connection method between the connecting seat 10 and the side post 102 can be screw connection, riveting, low-temperature welding, etc. This embodiment uses low-temperature welding. The design of the connecting seat 10 prevents the horizontal rib pull ring 5 from entering the interior of the side post 102, thus preventing the impact of concrete poured inside the square steel pipe 1 on the horizontal rib pull ring 5 and ensuring the detachability of the horizontal rib pull ring 5.

[0048] The 502 stud set includes a quick-release socket 8, such as... Figure 8 The horizontal reinforcing bar ring 5 is not tightly fitted with the connecting seat 10, but maintains a certain gap. The stud 502 on this gap is fitted with a quick-release sleeve 8. When the wall is rebuilt, you only need to dig out the quick-release sleeve 8 and rotate the stud 502 on the gap to remove the horizontal reinforcing bar ring 5, thus avoiding rotating the horizontal reinforcing bar and the large pieces of concrete attached to the horizontal reinforcing bar.

[0049] This embodiment provides a connection structure between square steel tube columns, such as... Figure 6 The square steel tube 1 includes an upper column 105 and a lower column 104. The flow plate 3 extends upward and forms an outer positioning area. The upper column 105 and the lower column 104 are respectively fixed to the flow plate 3 by high-strength bolt kits.

[0050] like Figure 9A positioning sleeve 106 is slidably fitted between the side columns 102 of the upper column 105 and the lower column 104 to form an inner positioning area. The positioning sleeve 106 is a through square steel tube 1 structure. The positioning sleeve 106 is also reinforced to the lower column 104 by high-strength bolts. After the upper column 105 is installed, the positioning sleeve 106 is further reinforced to the upper column 105 by high-strength bolts.

[0051] The embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. The basic concept of the present invention is to embed square steel pipes 1 in the supports of some EPS module walls, and use the stability of the square steel pipes 1 to achieve the tie bolts, long bolts and other connecting parts 4 to fix the wall panels 2 on both sides. The flow plate 3 realizes the integration of the column and other wall bodies in the casting and reduces the adhesion of the wall panels 2 to the concrete. Then, the sealing structure ensures that the connecting parts 4 can be removed after casting, so that the wall panels 2 can be removed quickly and accurately after the wall is rebuilt, preventing large-area damage to the wall panels 2. In addition, horizontal reinforcement rings 5 ​​are set on the square steel pipes 1, so that the removal and reconstruction of the horizontal reinforcement is convenient and quick, reducing the damage to the column when removing the horizontal reinforcement, and further expanding the advantages of the present invention in wall reconstruction. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. An EPS wall module connection structure for building construction, characterized in that, The system includes square steel pipes, wall panels, flow plates, connectors, and horizontal reinforcing rings. The square steel pipes include a central column, a connecting plate, and multiple side columns. Both the central column and the side columns are hollow columns and are fixedly connected by the connecting plate. Flow plates are arranged on the front and rear outer walls of the side columns, and wall panels are arranged on the outer walls of the flow plates. The connectors are long bolt kits. The side columns, flow plates, and wall panels are all provided with corresponding through holes and are fixedly connected together by the connectors, forming a casting space between the square steel pipes and the wall panels. Connecting sleeves are fitted onto the connectors at the casting space locations. The flow plates have a concave-convex cross-section, forming flow channels that connect the casting space and other wall modules. The sidewall of the wall panel is provided with tongue and groove joints for connecting other wall modules; A horizontal reinforcing ring is provided on the outer wall of the side column opposite to the connecting plate.

2. The EPS wall module connection structure for building construction according to claim 1, characterized in that: The cross-sectional shapes of the square steel tubes include L-shaped, T-shaped and cross-shaped, and the wall panels are corresponding L-shaped plates or straight plates. Multiple sets of flow plates and horizontal rib pull rings are provided.

3. The EPS wall module connection structure for building construction according to claim 2, characterized in that: The horizontal rib pull ring includes a stud and a pull ring. A threaded hole is opened on the outer wall of the side post opposite to the connecting plate. One end of the stud is threaded to the threaded hole, and the other end is threaded to the pull ring.

4. The EPS wall module connection structure for building construction according to claim 2, characterized in that: The horizontal rib pull ring includes a stud and a pull ring. A connecting seat is fixed on the outer wall of the side post opposite to the connecting plate. The connecting seat has a threaded hole. One end of the stud is threadedly connected to the threaded hole, and the other end is threadedly connected to the pull ring.

5. An EPS wall module connection structure for building construction according to claim 3 or 4, characterized in that: The stud is fitted with a quick-release sleeve.

6. The EPS wall module connection structure for building construction according to claim 5, characterized in that: A sealing ring is provided between the connecting sleeve and the side column, and between the quick-release sleeve and the side column or connecting seat.

7. The EPS wall module connection structure for building construction according to claim 2, characterized in that: The outer wall of the wall panel is provided with a groove to accommodate the outer end of the connector, and a sealing plate is provided on the outer end face of the groove.

8. The EPS wall module connection structure for building construction according to claim 2, characterized in that: The square steel tube includes an upper column and a lower column. The flow plate extends upward and forms an outer positioning area. The upper column and the lower column are fixed to the flow plate by high-strength bolt kits.

9. The EPS wall module connection structure for building construction according to claim 8, characterized in that: A positioning sleeve is slidably fitted between the side columns of the upper and lower columns to form an inner positioning area. The positioning sleeve is a through square steel tube structure.

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