Prefabricated hollow laminated slab

Abstract

The application provides an assembled hollow laminated slab, and relates to the technical field of building engineering. The assembled hollow laminated slab comprises a bottom plate, a reinforcing mold box, a truss plate, a cold extrusion sleeve and a hollow column, the plate edge of the bottom plate is connected with the side wall of the cross beam, the reinforcing mold box and the truss plate are arranged on the bottom plate, the top of the support column is provided with a support steel bar, the top end of the support steel bar penetrates through the bottom pipe opening of the cold extrusion sleeve, extends into the cold extrusion sleeve and is connected with the cold extrusion sleeve, the bottom of the hollow column is provided with a connecting steel bar, the bottom end of the connecting steel bar penetrates through the top pipe opening of the cold extrusion sleeve, extends into the cold extrusion sleeve and is connected with the cold extrusion sleeve. The application has the advantages of low assembly difficulty.

Description

Technical Field

[0001] This application relates to the field of building engineering technology, and in particular to a prefabricated hollow composite slab. Background Technology

[0002] Prefabricated hollow composite panels are a type of building material commonly used in prefabricated construction.

[0003] The existing prefabricated hollow composite slab mainly consists of five parts: a precast base slab, reinforcing formwork, steel truss slab, support columns, and post-cast concrete. During construction, workers first install the precast base slab onto steel beams to form a supporting foundation. Then, they install the reinforcing formwork and steel truss slab onto the precast base slab. Next, a crane is used to suspend the support columns to be installed on top of the already installed support columns, and welding equipment such as welding torches is used to weld all the reinforcing bars on the two support columns one by one. Finally, a mold is set on the precast base slab, and then concrete is poured to submerge the reinforcing formwork and steel truss slab and fill the gaps between the two support columns, so that the precast base slab, reinforcing formwork, steel truss slab, and support columns can form an integrated structure with the entire building through the post-cast concrete.

[0004] However, when welding the support column to be installed to the already installed support column, not only is a crane needed to keep the support column to be installed suspended above the already installed support column, but other people are also needed to hold the support column to be installed so that it is not easy to shake due to external forces such as wind during welding, which may lead to welding failure such as skewing or misalignment. Therefore, the assembly of prefabricated hollow composite slabs is quite difficult.

[0005] In view of this, there is a need to provide a prefabricated hollow composite panel. Utility Model Content

[0006] To address the issue of high assembly difficulty in existing prefabricated hollow composite slabs, this application provides a prefabricated hollow composite slab.

[0007] This application provides a prefabricated hollow composite slab, which adopts the following technical solution: including a base plate, a reinforcing mold box, a truss plate, a cold-extruded sleeve and hollow columns, wherein the edge of the base plate is connected to the side wall of the crossbeam; The reinforcing mold and the truss plate are disposed on the base plate; The top of the support column is provided with a support steel bar, and the top end of the support steel bar passes through the bottom opening of the cold extrusion sleeve, extends into the interior of the cold extrusion sleeve, and is connected to the cold extrusion sleeve. The bottom of the hollow column is provided with a connecting steel bar, and the bottom end of the connecting steel bar passes through the top opening of the cold extrusion sleeve, extends into the interior of the cold extrusion sleeve, and connects with the cold extrusion sleeve.

[0008] By adopting the above technical solution, the connection between the base plate and the crossbeam, the reinforcement mold box and truss plate are set on the base plate, and the supporting steel bars and connecting steel bars are connected by cold extrusion sleeves. This structural design achieves effective connection between the various components of the prefabricated hollow composite slab. Compared with the prior art, in the prior art, when the support columns to be installed are welded to the already installed support columns, a crane is required for suspension and manual support, which is prone to welding skew and misalignment, resulting in high assembly difficulty. However, this solution uses cold extrusion sleeves to connect the supporting steel bars and connecting steel bars, eliminating the need for long-term crane suspension and manual support, effectively reducing the assembly difficulty of the prefabricated hollow composite slab.

[0009] Specifically, the cold-extruded sleeve includes a tube body, a lower limiting shrink ring, and an upper limiting shrink ring. Multiple lower dividing grooves are spaced apart along the length of the tube body at the bottom opening. The multiple lower dividing grooves divide the bottom end of the tube body into multiple lower splicing parts. The lower limiting shrink ring can be sleeved on the bottom end of the tube body and make each of the lower splicing parts close to each other and clamp the connecting steel bar. Multiple upper dividing grooves are spaced apart along the length of the pipe body at the top opening. These multiple upper dividing grooves divide the top of the pipe body into multiple upper splicing parts. The upper limit shrink ring can be fitted onto the top of the pipe body and bring each of the upper splicing parts close to each other and clamp the supporting steel bar.

[0010] By adopting the above technical solution, the lower dividing groove at the bottom of the pipe body divides the bottom end into multiple lower splicing parts. The lower limiting shrink ring is sleeved on the bottom end of the pipe body to bring the lower splicing parts close to each other and clamp the connecting steel bars. The upper dividing groove at the top of the pipe body divides the top end into multiple upper splicing parts. The upper limiting ring is sleeved on the top end of the pipe body to bring the upper splicing parts close to each other and clamp the supporting steel bars. This achieves a stable connection between the supporting steel bars and the connecting steel bars in the cold extrusion sleeve, eliminating the need for welding and reducing the assembly difficulty of the prefabricated hollow composite slab.

[0011] Furthermore, the cold-extruded sleeve also includes a positioning pin. A positioning hole leading to the inside of the tube is provided in the middle of the tube body. One end of the positioning pin passes through the positioning hole and is inserted into the inside of the tube body. The positioning pin can abut against the top end of the supporting steel bar and restrict the top end of the supporting steel bar from passing through the positioning hole along the inside of the tube body.

[0012] By adopting the above technical solution, in the prefabricated hollow composite slab, the cold-extruded sleeve is equipped with a positioning pin. The positioning pin passes through the positioning hole in the middle of the tube and is inserted into the tube, abutting against the top of the supporting steel bar. This can prevent the top of the supporting steel bar from passing through the positioning hole, making it easier to accurately install the supporting steel bar and reducing the assembly difficulty.

[0013] Furthermore, the positioning pin has a lower abutment surface and an upper abutment surface. The supporting steel bar abuts against the lower abutment surface, and the connecting steel bar abuts against the upper abutment surface, clamping the positioning pin between the connecting steel bar and the abutment steel bar.

[0014] By adopting the above technical solution, the lower abutment surface of the positioning pin abuts against the supporting steel bar, and the upper abutment surface abuts against the connecting steel bar, so that the connecting steel bar and the supporting steel bar can clamp the positioning pin, thereby restricting the position of the supporting steel bar and the connecting steel bar in the cold extrusion sleeve, ensuring the stability and accuracy of the connection between the two, and reducing the assembly difficulty of the prefabricated hollow composite slab.

[0015] Furthermore, it also includes auxiliary components, which include a limiting cylinder, a telescopic rod, a connecting unit, a limiting block, and a limiting bolt. The limiting cylinder is detachably connected to the pipe body, and the length direction of the limiting cylinder is parallel to the length direction of the pipe body. The bottom end of the telescopic rod is connected to the connecting unit, and the connecting unit is detachably connected to the side wall of the supporting steel bar. The portion of the telescopic rod near the top end passes through the bottom opening of the limiting cylinder and is inserted into the limiting cylinder, forming an abutting protrusion. The abutting protrusion can slide along the inside of the limiting cylinder. The limiting cylinder has an oblong hole leading into the cylinder along its own length direction. The limiting block has a screw hole adapted to the limiting bolt. The screw end of the limiting bolt passes through the oblong hole and is screwed into the screw hole of the limiting block. The inner wall of the limiting cylinder abuts against the limiting block and can restrict the limiting block from rotating together with the limiting bolt. When the limiting bolt is screwed into the screw hole of the limiting block, the limiting block can clamp the edge of the waist-shaped hole with the screw head end of the limiting bolt and restrict the limiting block from moving along the waist-shaped hole. The limiting block can also abut against the abutting protrusion and restrict the abutting protrusion from passing the limiting block and approaching the opening of the limiting cylinder.

[0016] By adopting the above technical solution, since the supporting steel bars and connecting steel bars need to occupy half of the space inside the cold-extruded sleeve before cold extrusion, the user can first adjust the position of the limiting bolt and the limiting block along the waist-shaped hole according to the length of the tube. This allows the telescopic rod to move from abutting against the inner top wall of the limiting cylinder to abutting against the limiting block. At this point, the bottom end of the telescopic rod has moved exactly half the length of the tube. This allows the user to first connect the auxiliary assembly to the tube and position the supporting steel bars at the bottom end of the tube, with the abutting protrusion of the telescopic rod abutting against the limiting block. Then, the user connects the telescopic rod to the supporting steel bars and loosens the tube and the auxiliary assembly. The auxiliary assembly will contract under its own weight until it expands or contracts. The rod abuts against the inner top wall of the limiting cylinder, and at this time the supporting steel bar occupies half of the position inside the cold extrusion sleeve. Then, the user can use a crane or other equipment to hoist the connecting steel bar of the hollow column into the tube body and abut against the supporting steel bar. Then, the extrusion equipment matched with the cold extrusion sleeve is used to bring the lower limit shrink ring and the upper limit shrink ring closer to each other and connect the supporting steel bar and the connecting steel bar. Finally, the auxiliary components are removed from the tube body and the supporting steel bar. This not only eliminates the need to open positioning holes on the tube wall of the cold extrusion sleeve that would weaken the structure, but also prevents the supporting steel bar and the connecting steel bar from having an unstable positioning pin abutting against each other after being connected by the cold extrusion sleeve, thereby improving the connection strength between the supporting column and the hollow column.

[0017] Furthermore, a scale is provided on the side of the waist-shaped hole away from the inside of the limiting cylinder along the length direction of the waist-shaped hole.

[0018] By adopting the above technical solution, a scale is set on the waist-shaped hole, which facilitates precise control of the position of the telescopic rod in the limiting cylinder during installation, thereby improving installation accuracy.

[0019] Furthermore, the connecting unit includes an elastic element and a pair of grippers. The bottom end of the telescopic rod is provided with a gripper shaft. The gripper bodies of the pair of grippers are both hinged to the gripper shaft. The elastic element is provided on the gripper shaft and can drive the grippers of the pair of grippers to move closer to each other.

[0020] By adopting the above technical solution, the elastic element is set on the gripper shaft, which can drive the grippers of a pair of grippers to move closer to each other, so that the connecting unit can be stably connected to the side wall of the supporting steel bar, which facilitates the connection between the telescopic rod and the supporting steel bar, provides a foundation for subsequent auxiliary installation, and helps to reduce the assembly difficulty of the prefabricated hollow composite slab.

[0021] Furthermore, the limiting cylinder also includes a female Velcro strap and a female Velcro strap, one end of which is connected to the limiting cylinder, and the limiting cylinder can be connected to the tube body via the other ends of the female Velcro strap and the female Velcro strap.

[0022] By adopting the above technical solution, the mother and daughter magic belts are connected to each other around the pipe body, realizing the detachable connection between the limiting cylinder and the pipe body. This facilitates the installation and disassembly of the limiting cylinder, and makes it easy to use and adjust its position in different construction scenarios. It also improves the convenience and adaptability of auxiliary components in the assembly process of prefabricated hollow composite slabs.

[0023] In summary, this application includes the following beneficial technical effects: The system includes a base plate, reinforcing molds, truss plates, cold-extruded sleeves, and hollow columns. The edges of the base plate are connected to the side walls of the crossbeams. The reinforcing molds and truss plates are mounted on the base plate. The top of the support column is equipped with supporting steel bars, the top of which passes through the bottom opening of the cold-extruded sleeve and extends into the interior of the sleeve, connecting to it. The bottom of the hollow column is equipped with connecting steel bars, the bottom of which passes through the top opening of the cold-extruded sleeve and extends into the interior of the sleeve, connecting to it. Compared with existing technologies, in the prior art, when welding the support column to be installed to the already installed support column, a crane is required for suspension and manual support, which can easily lead to welding skewing, misalignment, etc., resulting in high assembly difficulty. In contrast, this solution uses cold-extruded sleeves to connect the supporting steel bars and connecting steel bars, eliminating the need for long-term crane suspension and manual support, effectively reducing the assembly difficulty of the prefabricated hollow composite slab. Attached Figure Description

[0024] Figure 1 This is a perspective view of the first embodiment of this application; Figure 2 This is a top view of the first embodiment of this application; Figure 3 It is along Figure 2 A schematic sectional view taken along the AA direction, showing only part of the supporting columns, hollow columns, base plate and reinforcing mold; Figure 4 This is a perspective view of the second embodiment of this application; Figure 5 It is along Figure 4 A schematic cross-sectional view of the central axis of the intercooled extrusion sleeve, showing only part of the supporting reinforcement, connecting reinforcement, bottom plate and reinforcing mold; Figure 6 yes Figure 4 A schematic enlarged view of region B, showing the drive gear.

[0025] Reference numerals: 1. Base plate; 2. Truss plate; 3. Cold-extruded sleeve; 31. Tube body; 311. Lower splice; 32. Lower limiting shrink ring; 33. Upper limiting shrink ring; 34. Positioning pin; 4. Hollow column; 41. Connecting steel bar; 5. Support column; 51. Supporting steel bar; 6. Crossbeam; 7. Auxiliary assembly; 71. Limiting cylinder; 711. Female magic belt; 712. Female magic belt; 72. Telescopic rod; 73. Connecting unit; 731. Elastic element; 732. Clamp; 74. Limiting block; 75. Limiting bolt. Detailed Implementation

[0026] The following is in conjunction with the appendix Figure 1-6 Further explanation: See Figure 1 , Figure 2 and Figure 3 In the first embodiment, the prefabricated hollow composite slab provided in this application is installed on a building foundation. The building foundation consists of four supporting columns 5 and crossbeams 6 made of steel bars between each supporting column 5. The prefabricated hollow composite slab specifically includes: six base plates 1, multiple reinforcing molds (not shown in the figure), eighteen truss plates 2, four hollow columns 4, and multiple cold-extruded sleeves 3. The base plates 1 can be precast concrete components. The internal steel bars of the precast concrete components extend from the side plates of the base plates 1 and are connected to the crossbeams 6. Each base plate 1 has at least one reinforcing mold on its top. The reinforcing mold can be a plastic product made of special plastic as raw material and formed by a special process. Each base plate 1 also has three truss plates 2 made of steel bars on its top.

[0027] See Figure 1 , Figure 2 and Figure 3Each support column 5 has multiple supporting steel bars 51 at its top, and each hollow column 4 has multiple connecting steel bars 41 at its bottom. The cold-extruded sleeve 3 and the connecting steel bars 41 correspond one-to-one with the supporting steel bars 51. Each cold-extruded sleeve 3 includes a tube body 31, a positioning pin 34, a lower limiting ring 32, and an upper limiting ring 33. Multiple lower dividing grooves are spaced apart along the length of the tube body 31 at the bottom opening of the tube body 31, dividing the bottom end of the tube body 31 into multiple lower splicing parts 311. Multiple upper dividing grooves are spaced apart along the length of the tube body 31 at the top opening of the tube body 31, dividing the top end of the tube body 31 into multiple upper splicing parts. A positioning hole leading to the inside of the tube is opened in the middle of the tube body 31. The cross-section of the positioning pin 34 and the positioning hole can be rectangular, so that the positioning pin 34 has a lower abutment surface and an upper abutment surface. The worker can first place the positioning pin... One end of the positioning pin 34 is inserted into the tube body 31 through the positioning hole. Then, the tube body 31 is fitted onto the corresponding support steel bar 51 so that the positioning pin 34 can abut against the top of the support steel bar 51 and restrict the top of the support steel bar 51 from passing through the positioning hole along the inside of the tube body 31. Then, the hollow column 4 is hoisted directly above the corresponding support column 5, and the corresponding connecting steel bar 41 is inserted into the tube body 31 so that the support steel bar 51 abuts against the lower abutment surface and the connecting steel bar 41 abuts against the upper abutment surface. Then, the worker can use a hydraulically powered cold extrusion tool to extrude the cold extrusion sleeve 3 so that the upper limit shrink ring 33 and the lower limit shrink ring 32 are close to each other. The lower limit shrink ring 32 can be fitted onto the bottom end of the tube body 31 so that each lower splice part 311 is close to each other and clamps the connecting steel bar 41. The upper limit shrink ring 33 can be fitted onto the top end of the tube body 31 so that each upper splice part is close to each other and clamps the support steel bar 51.

[0028] The working principle of the first embodiment of this application is as follows: The base plate 1 is connected to the crossbeam 6, the reinforcing mold box and truss plate 2 are set on the base plate 1, and the supporting steel bars 51 and connecting steel bars 41 are connected by cold-extruded sleeves 3. This structural design realizes the effective connection between the components of the prefabricated hollow composite slab. Compared with the prior art, when the supporting column 5 to be installed is welded to the already installed supporting column 5, a crane is required for suspension and manual support, which is prone to welding skew and misalignment, resulting in high assembly difficulty. However, this solution uses cold-extruded sleeves 3 to connect the supporting steel bars 51 and connecting steel bars 41, eliminating the need for long-term crane suspension and manual support, effectively reducing the assembly difficulty of the prefabricated hollow composite slab.

[0029] See Figure 4 , Figure 5 and Figure 6In the second embodiment, the assembled hollow composite plate further includes an auxiliary assembly 7. The auxiliary assembly 7 includes a limiting cylinder 71, a telescopic rod 72, a connecting unit 73, a limiting block 74, and a limiting bolt 75. The limiting cylinder 71 is detachably connected to the pipe body 31, and the length direction of the limiting cylinder 71 is parallel to the length direction of the pipe body 31. The bottom end of the telescopic rod 72 is connected to the connecting unit 73. The connecting unit 73 includes an elastic element 731 and a pair of grippers 732. The bottom end of the telescopic rod 72 is provided with a gripper 732 shaft. The gripper bodies of the pair of grippers 732 are hinged to the gripper 732 shaft. The elastic element 731 is provided on the gripper 732 shaft. The elastic element 731 can be a torsion spring, so that the elastic element 731... 1. The claws of a pair of grippers 732 can be driven to move closer to each other, so that the connecting unit 73 can be firmly clamped on the supporting steel bar 51. The part of the telescopic rod 72 near the top of the rod passes through the bottom opening of the limiting cylinder 71 and is inserted into the limiting cylinder 71, forming an abutting protrusion. The abutting protrusion can slide along the inside of the limiting cylinder 71. The limiting cylinder 71 has a waist-shaped hole leading into the cylinder along its own length direction. The limiting block 74 has a screw hole that matches the limiting bolt 75. The screw end of the limiting bolt 75 passes through the waist-shaped hole and is screwed into the screw hole of the limiting block 74. The inner wall of the limiting cylinder 71 abuts against the limiting block 74 and can restrict the limiting block 74 from rotating together with the limiting bolt 75.

[0030] The working principle of the second embodiment of this application is as follows: Before cold extrusion, the supporting steel bar 51 and the connecting steel bar 41 need to occupy half of the space inside the cold extrusion sleeve 3. The user can first adjust the positions of the limiting bolt 75 and the limiting block 74 along the oblong hole according to the length of the tube body 31. This allows the telescopic rod 72 to move from contact with the inner top wall of the limiting cylinder 71 to contact with the limiting block 74. At this point, the bottom end of the telescopic rod 72 should have moved exactly half the length of the tube body 31. This allows the user to first connect the auxiliary assembly 7 to the tube body 31, positioning the supporting steel bar 51 at the bottom of the tube body 31, with the abutting protrusion of the telescopic rod 72 contacting the limiting block 74. Then, connect the telescopic rod 72 to the supporting steel bar 51 and loosen the tube body 31 and the auxiliary assembly 7. The auxiliary assembly 7 will retract under its own weight until the telescopic rod 72 contacts the limiting block 74. The inner top wall of the sleeve 71 abuts against the support steel bar 51, which occupies half of the position inside the cold extrusion sleeve 3. Then, the user can use a crane or other equipment to hoist the connecting steel bar 41 of the hollow column 4 into the tube body 31 and abut against the support steel bar 51. Then, the extrusion equipment matched with the cold extrusion sleeve 3 is used to bring the lower limit shrink ring 32 and the upper limit shrink ring 33 closer together and connect the support steel bar 51 and the connecting steel bar 41. Finally, the auxiliary assembly 7 is removed from the tube body 31 and the support steel bar 51. This not only eliminates the need to open positioning holes on the tube wall of the cold extrusion sleeve 3 that would weaken the structure, but also ensures that after the support steel bar 51 and the connecting steel bar 41 are connected by the cold extrusion sleeve 3, there will be no unstable positioning pin 34 abutting between the support steel bar 51 and the connecting steel bar 41, thereby improving the connection strength between the support column 5 and the hollow column 4.

[0031] Specifically, two female Velcro straps 711 and two female Velcro straps 712 can be set on the limiting cylinder 71. One end of each female Velcro strap 711 and female Velcro strap 712 is connected to the limiting cylinder 71, so that the limiting cylinder 71 can be connected to the tube body 31 by passing around the other end of the female Velcro strap 711 and the corresponding female Velcro strap 712. This facilitates the installation and disassembly of the limiting cylinder 71, and makes it easy to use and adjust its position in different construction scenarios. This improves the ease of use and adaptability of the auxiliary components 7 in the assembly of prefabricated hollow composite panels. Scales (not shown in the figure) can also be set on the side of the waist-shaped hole away from the inside of the limiting cylinder 71 along the length of the waist-shaped hole. This allows for precise control of the position of the telescopic rod 72 inside the limiting cylinder 71 during installation, improving installation accuracy.

[0032] It should be noted that the above are all preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A prefabricated hollow composite slab, installed on a support column (5) and a crossbeam (6), characterized in that: It includes a base plate (1), a reinforcing mold box, a truss plate (2), a cold-extruded sleeve (3) and a hollow column (4), wherein the edge of the base plate (1) is connected to the side wall of the crossbeam (6); The reinforcing mold and the truss plate (2) are disposed on the base plate (1); The top of the support column (5) is provided with a support steel bar (51), and the top end of the support steel bar (51) passes through the bottom opening of the cold extrusion sleeve (3) and extends into the interior of the cold extrusion sleeve (3) and is connected to the cold extrusion sleeve (3). The bottom of the hollow column (4) is provided with a connecting steel bar (41). The bottom end of the connecting steel bar (41) passes through the top opening of the cold extrusion sleeve (3) and extends into the interior of the cold extrusion sleeve (3) and is connected to the cold extrusion sleeve (3).

2. The assembled hollow composite slab according to claim 1, characterized in that: The cold-extruded sleeve (3) includes a tube body (31), a lower limiting shrink ring (32) and an upper limiting shrink ring (33). The bottom opening of the tube body (31) is provided with a plurality of lower dividing grooves spaced apart along the length of the tube body (31). The plurality of lower dividing grooves divide the bottom end of the tube body (31) into a plurality of lower splicing parts (311). The lower limiting shrink ring (32) can be sleeved on the bottom end of the tube body (31) and make each of the lower splicing parts (311) close to each other and clamp the connecting steel bar (41). The top opening of the tube (31) is provided with multiple upper dividing grooves spaced apart along the length of the tube (31). The multiple upper dividing grooves divide the top of the tube (31) into multiple upper splicing parts. The upper limit shrink ring (33) can be sleeved on the top of the tube (31) and make each of the upper splicing parts close to each other and clamp the supporting steel bar (51).

3. The assembled hollow composite slab according to claim 2, characterized in that: The cold-extruded sleeve (3) also includes a positioning pin (34). A positioning hole leading to the inside of the tube is provided in the middle of the tube body (31). One end of the positioning pin (34) passes through the positioning hole and is inserted into the inside of the tube body (31). The positioning pin (34) can abut against the top end of the supporting steel bar (51) and restrict the top end of the supporting steel bar (51) from passing through the positioning hole along the inside of the tube body (31).

4. The assembled hollow composite slab according to claim 3, characterized in that: The positioning pin (34) has a lower abutment surface and an upper abutment surface. The supporting steel bar (51) abuts against the lower abutment surface, and the connecting steel bar (41) abuts against the upper abutment surface, clamping the positioning pin (34) between the connecting steel bar (41) and the supporting steel bar (51).

5. The assembled hollow composite slab according to claim 2, characterized in that: It also includes an auxiliary assembly (7), which includes a limiting cylinder (71), a telescopic rod (72), a connecting unit (73), a limiting block (74), and a limiting bolt (75). The limiting cylinder (71) is detachably connected to the pipe body (31), and the length direction of the limiting cylinder (71) is parallel to the length direction of the pipe body (31). The bottom end of the telescopic rod (72) is connected to the connecting unit (73), and the connecting unit (73) is detachably connected to the side wall of the supporting steel bar (51). The portion of the telescopic rod (72) near the top end passes through the limiting cylinder (71). 1) The bottom opening of the cylinder is inserted into the inside of the limiting cylinder (71) and forms an abutting protrusion. The abutting protrusion can slide along the inside of the limiting cylinder (71). The limiting cylinder (71) has a waist-shaped hole that leads into the cylinder along its own length direction. The limiting block (74) has a screw hole that matches the limiting bolt (75). The screw end of the limiting bolt (75) passes through the waist-shaped hole and is screwed into the screw hole of the limiting block (74). The inner wall of the limiting cylinder (71) abuts against the limiting block (74) and can restrict the limiting block (74) from rotating together with the limiting bolt (75). When the limiting bolt (75) is screwed into the screw hole of the limiting block (74), the limiting block (74) can clamp the edge of the waist-shaped hole with the screw head end of the limiting bolt (75) and restrict the limiting block (74) from moving along the waist-shaped hole. The limiting block (74) can also abut against the abutting protrusion and restrict the abutting protrusion from passing the limiting block (74) and approaching the opening of the limiting cylinder (71).

6. The assembled hollow composite slab according to claim 5, characterized in that: The waist-shaped hole has a scale along the length of the hole on the side away from the inside of the limiting cylinder (71).

7. The assembled hollow composite slab according to claim 5, characterized in that: The connecting unit (73) includes an elastic element (731) and a pair of grippers (732). The bottom end of the telescopic rod (72) is provided with a gripper (732) shaft. The gripper bodies of the pair of grippers (732) are hinged to the gripper (732) shaft. The elastic element (731) is provided on the gripper (732) shaft and can drive the grippers (732) to move closer to each other.

8. A prefabricated hollow composite slab according to claim 5, characterized in that: The limiting cylinder (71) also includes a female Velcro strap (711) and a female Velcro strap (712). One end of the female Velcro strap (711) and the female Velcro strap (712) are connected to the limiting cylinder (71), and the limiting cylinder (71) can be connected to the tube body (31) by passing around the tube body (31) via the other end of the female Velcro strap (711) and the female Velcro strap (712).

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