Roof air shaft opening anti-falling device and construction method

Abstract

The invention provides a roof air shaft opening anti-falling device and a construction method. The roof air shaft opening anti-falling device comprises a winding drum, a winding assembly, an anti-falling net and an adjustable cover plate. An accommodating space and an opening formed in the middle of the winding drum in the length direction are formed in the winding drum; the winding assembly comprises a winding roller and a rocker, the winding roller is rotatably arranged in the containing space, and the rocker is arranged on the outer side of the winding drum and connected to the winding roller; one end of the anti-falling net is wound on the winding roller, and the other end is connected to the adjustable cover plate; the adjustable cover plate is connected with the opening in a buckled mode, and the length of the adjustable cover plate is adjustable. By arranging the winding drum and the adjustable cover plate, the anti-falling net is convenient to store, the anti-falling net can be stably and conveniently fixed to the roof air shaft, meanwhile, the shape of the anti-falling net can be limited, the phenomenon that the anti-falling net is intertwined and knotted after being used for a long time is prevented, and the protection effect of the anti-falling net is ensured.

Description

Technical Field

[0001] The present invention belongs to the technical field of protective structures, and particularly relates to a device for preventing falling at the opening of a roof air shaft and a construction method therefor. Background Art

[0002] Roof air shafts are mainly used for ventilation and air change inside buildings. By capturing wind energy, air shafts promote air flow inside buildings to achieve natural ventilation. In case of emergencies such as fires, air shafts can serve as smoke exhaust channels to quickly remove indoor smoke, buying time for people to escape. At the same time, they can also blow air into the room during a fire to prevent smoke from entering the escape passage and provide fresh air for escaping people. During the construction process of a building, a protective device needs to be installed at the opening of the air shaft to prevent objects or people from falling, and it should be removed after the construction is completed. The anti-falling devices for air shaft openings in the prior art mainly use fiber rope nets fixed to the concrete at the air shaft opening by cement nails. The setting of cement nails not only damages the appearance quality of the concrete, but also has limited self-bearing capacity. When the anti-falling net is subjected to a certain force, the cement nails will become loose, affecting the protective performance of the anti-falling net. Moreover, the anti-falling net is easily entangled and deformed when exposed to the rain environment for a long time, and it is difficult to be reused. Summary of the Invention

[0003] To solve the above technical problems, the present invention provides a device for preventing falling at the opening of a roof air shaft and a construction method therefor, which can stably and conveniently fix the anti-falling net on the roof air shaft, ensure the protective effect of the anti-falling net, and is convenient for turnover and use.

[0004] The technical solution adopted by the present invention is: a device for preventing falling at the opening of a roof air shaft, including a drum, a winding assembly, an anti-falling net, and an adjustable cover plate; a receiving space is provided inside the drum, and an opening is provided in the middle of the drum in the length direction; the winding assembly includes a winding roller and a rocker, the winding roller is rotatably arranged in the receiving space, the rocker is arranged outside the drum and connected to the winding roller; one end of the anti-falling net is wound around the winding roller, and the other end is connected to the adjustable cover plate; the adjustable cover plate is snap-connected to the opening, and its length is adjustable.

[0005] Further, the anti-falling net is a flexible metal net.

[0006] Further, the drum is a hollow cylinder, including an arc surface and end plates provided at both ends of the arc surface, the opening is provided in the arc surface; both ends of the winding roller are rotatably connected to the end plates; at least one end of the winding roller extends out of the end plate and is connected to the hand rocker.

[0007] Further, the adjustable cover plate includes a fixed section and telescopic sections connected to both ends of the fixed section. The shape of the fixed section is adapted to the opening, and a telescopic cavity for accommodating the telescopic sections is provided; the anti-falling net is connected to the fixed section, and a handle is provided at one end of the fixed section opposite to the anti-falling net.

[0008] Further, both the fixed section and the telescopic sections are square pipe bodies; several of the telescopic sections are nested and connected in sequence.

[0009] Further, the adjustable cover plate further includes a limit post and a limit card slot; the limit card slot is arranged on the corresponding side walls of the fixed section and the telescopic sections, the limit post is abutted in the limit card slot through an elastic member, and the elastic member is arranged inside the telescopic section.

[0010] Further, a sliding limit component is further included. The sliding limit component includes an arc-shaped tooth and a limit pull rod connected to the arc-shaped tooth. The winding roller is further provided with a limit groove extending along its circumferential direction. The limit pull rod is slidably arranged in the limit groove and can drive the arc-shaped tooth to slide along the inner wall of the winding roller to be clamped with the anti-falling net.

[0011] Further, the sliding limit component further includes a limit stop and an arc-shaped limit plate. The limit stops are oppositely arranged on one side of the opening close to the limit groove. The limit member is provided with an arc-shaped card slot, and both ends of the arc-shaped limit plate are embedded in the arc-shaped card slot; the arc-shaped teeth are uniformly arranged on one side of the arc-shaped limit plate close to the opening, and the limit pull rod is connected to the arc-shaped limit plate.

[0012] Further, the distance between the arc-shaped teeth is adapted to the mesh holes of the anti-falling net.

[0013] The construction method of the anti-falling device for the roof air shaft opening as described above includes the following steps:

[0014] Place the winding drum outside the well wall of the roof air shaft so that both ends of the winding drum are attached to the columns of the roof air shaft;

[0015] Pull the handle to unfold the anti-falling net and extend the adjustable cover plate to the outside of the well wall on the other side;

[0016] Adjust the elongation of the adjustable cover plate so that both ends of the adjustable cover plate are stuck on the columns on the other side;

[0017] Lock the anti-falling net through the sliding limit component;

[0018] After the construction is completed, unlock the anti-falling net through the sliding limit component, adjust the adjustable cover plate to contract, and wind up the anti-falling net through the rocker so that the adjustable cover plate is buckled on the winding drum.

[0019] The advantages and positive effects of the present invention are as follows:

[0020] (1) By providing a winding drum and an adjustable cover plate, not only is the anti-falling net easy to store, but it can also be stably and conveniently fixed on the roof air shaft. At the same time, the shape of the anti-falling net can be limited to prevent entanglement and knotting during long-term use, ensuring the protective effect of the anti-falling net.

[0021] (2) After the device is constructed, it can be conveniently removed as a whole, which not only improves the installation and removal efficiency of the windfall device, reduces the operation difficulty, but also enables the overall device to be recycled, reducing the construction cost;

[0022] (3) The anti-falling net is a flexible metal net, which has good flexibility, plasticity and rigidity, providing a reliable protective effect; the overall structure is compact, reducing space occupation and facilitating transportation and storage. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic diagram of the unused state of a specific embodiment of the present invention;

[0024] Figure 2 is a schematic diagram of the anti-falling net being unfolded in a specific embodiment of the present invention;

[0025] Figure 3 is a schematic diagram of the winding assembly in a specific embodiment of the present invention;

[0026] Figure 4 is a schematic diagram of the structure of the limiting stop in a specific embodiment of the present invention;

[0027] Figure 5 is a schematic diagram of the use of a specific embodiment of the present invention.

[0028] In the figure:

[0029] 1, winding drum; 11, opening; 12, limiting groove; 2, anti-falling net; 3, winding assembly; 31, winding roller; 32, rocker; 4, adjustable cover plate; 41, fixed section; 42, telescopic section; 43, limiting column; 44, handle; 5, sliding limiting assembly; 51, arc teeth; 52, limiting pull rod; 53, arc limiting plate; 54, limiting stop; 6, column. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] The embodiments of the present invention will be described below with reference to the accompanying drawings.

[0031] As Figures 1 to 5As shown in the figure, an anti-falling device for the roof air shaft opening according to an embodiment of the present invention includes a winding drum 1, a winding assembly 3, an anti-falling net 2 and an adjustable cover plate 4; a receiving space is provided in the winding drum 1, and an opening 11 is provided in the middle of the winding drum 1 in the length direction; the winding assembly 3 includes a winding roller 31 and a rocker 32, the winding roller 31 is rotatably arranged in the receiving space, the rocker 32 is arranged outside the winding drum 1 and connected to the winding roller 31; one end of the anti-falling net 2 is wound around the winding roller 31, and the other end is connected to the adjustable cover plate 4; the adjustable cover plate 4 is snap-connected to the opening 11, and its length is adjustable.

[0032] In the implementation of the present application, the receiving space of the winding drum 1 can accommodate the anti-falling net 2 wound on the winding assembly 3, and the anti-falling net 2 can be unfolded outward through its opening 11; the width of the anti-falling net 2 is made according to the size of the opening of the roof air shaft to be protected, the length of the opening 11 is adapted to the width of the anti-falling net 2, and the length of the winding drum 1 is greater than the length of the opening 11; the winding assembly 3 is used to control the unfolding or winding of the anti-falling net 2. By rotating the rocker 32, the winding roller 31 can be driven to rotate, and the anti-falling net 2 can be unfolded or wound on the winding roller 31; correspondingly, when the anti-falling net 2 is wound on the winding roller 31, the adjustable cover plate 4 is snapped at the opening 11 to close the winding drum 1; when the anti-falling net 2 is unfolded, the adjustable cover plate 4 is located at the opposite end of the winding drum 1. By adjusting the length of the adjustable cover plate 4, it can cooperate with the winding drum 1 and be respectively clamped on the columns 6 around the wellhead of the roof air shaft, so as to realize the connection between the anti-falling opening device and the roof air shaft; through the above technical solution, the winding drum 1 and the adjustable cover plate 4 not only have the function of storing the anti-falling net 2, but also can stably and conveniently fix the device on the roof air shaft; in addition, the adjustable cover plate 4 has good rigidity, and both ends of the anti-falling net 2 are respectively fixed on the winding roller 31 and the adjustable cover plate 4, which can limit the shape of the anti-falling net 2 to prevent it from being entangled and knotted during long-term use; and this setting enables the device to be conveniently removed as a whole after the construction is completed, which not only improves the installation and disassembly efficiency of the anti-falling device, reduces the operation difficulty, but also enables the whole device to be recycled, reduces the construction cost; the overall structure is compact, reduces the space occupation, and is convenient for transportation and storage.

[0033] Further, in the embodiment of the present application, the anti-falling net 2 is a flexible metal net, which has certain flexibility and plasticity itself, can be woven into a net structure and will not break when being wound and deformed; at the same time, it has certain rigidity and can resist the impact force of falling objects to provide reliable protection; preferably, the anti-falling net 2 is made of galvanized metal net to prevent metal oxidation and rust and extend the service life of the anti-falling net 2.

[0034] Further, in the embodiment of the present application, the winding drum 1 is a hollow cylinder, including an arc surface and end plates provided at both ends of the arc surface. The opening 11 is provided on the arc surface; both ends of the winding roller 31 are rotatably connected to the end plates; at least one end of the winding roller 31 extends out of the end plate and is connected to the hand rocker 32.

[0035] In an alternative technical solution of the above embodiment, as Figure 3 shown, the winding roller 31 includes a roller shaft and winding discs oppositely provided at both ends of the roller shaft. The anti-falling net 2 is wound between the two winding discs; a mounting seat is provided in the middle of the end plate at one end of the winding drum 1, and a connecting bearing is provided in the middle of the end plate at the other end; both ends of the roller shaft extend out of the winding discs, one end of which is rotatably connected to the mounting seat, and the other end passes through the connecting bearing and is connected to the hand rocker 32; the hand rocker 32 includes a rocker handle and a hand grip. One end of the rocker handle is vertically connected to the extending end of the roller shaft, and the other end is rotatably connected to the hand grip; by rotating the hand grip, the roller shaft can be driven to rotate, so as to realize the winding or unfolding of the anti-falling net 2.

[0036] Further, in the embodiment of the present application, the adjustable cover plate 4 includes a fixed section 41 and telescopic sections 42 connected to both ends of the fixed section 41. The shape of the fixed section 41 is adapted to the opening 11, and a telescopic cavity for accommodating the telescopic section 42 is provided; the anti-falling net 2 is connected to the fixed section 41, and a handle is provided at one end of the fixed section 41 opposite to the anti-falling net 2. The fixed section 41 is directly connected to the anti-falling net 2, which can play a good role in fixing and supporting the anti-falling net 2 to prevent it from being entangled and deformed during construction; at the same time, the fixed section 41 can be well matched with the opening 11 and is buckled at the opening 11 in the unused state to close the winding drum 1; by designing the handle, the adjustable cover plate 4 can be pulled more conveniently and flexibly, so as to realize the unfolding of the anti-falling net 2, and can also be used as a handle 44 during the transportation of the whole device; by designing the fixing member to have a shrinking cavity and matching the shrinking cavity with the shrinking section, the length of the adjustable cover plate 4 is adjusted to adapt to different length requirements when the device is clamped on the roof air shaft opening through the adjustable cover plate 4; preferably, the telescopic sections 42 are symmetrically arranged relative to the fixed section 41 to improve the force uniformity of the whole device.

[0037] Furthermore, in the embodiment of the present application, both the fixed section 41 and the telescopic section 42 are square pipe bodies, and a plurality of telescopic sections 42 are nested and connected in sequence. Specifically, a plurality of telescopic sections 42 are provided at both ends of the fixed section 41. Each telescopic section 42 is provided with a telescopic cavity for accommodating the adjacent telescopic section 42. The shape and size of the telescopic section 42 adjacent to the fixed section 41 are adapted to the inner wall of the fixed section 41. At the same time, the shape and size of the telescopic section 42 far from the fixed section 41 are adapted to the inner wall of the telescopic section 42 adjacent to this telescopic section 42 and close to the fixed section 41, so that all the retractable sections can be retracted into the telescopic section 42 closer to the fixed section 41, and all the telescopic sections 42 can be retracted into the fixed section 41. By setting the fixed section 41 and the telescopic section 42 as square pipe bodies, compared with circular pipe bodies, they have better stability when bearing pressure and torque, thus improving the structural strength of the entire adjustable cover plate 4. At the same time, it is beneficial for the side wall of the adjustable cover plate 4 to be connected to the column 6 of the roof air shaft opening in the form of a plane, so that the contact area is larger and the connection is more stable and reliable. The nested connection method makes the telescopic sections 42 form a tight fit, further enhancing the integrity and stability of the adjustable cover plate 4.

[0038] Furthermore, in the above embodiment, the adjustable cover plate 4 further includes a limit post 43 and a limit card slot; the limit card slot is arranged on the corresponding side walls of the fixed section 41 and the telescopic section 42. The limit post 43 is abutted against the limit card slot through an elastic member, and the elastic member is arranged inside the telescopic section 42. Specifically, limit card slots are respectively arranged at both ends of the fixed section 41. The limit card slots can be arranged on any side wall of the fixed section 41 or on two adjacent side walls. An elastic member is correspondingly arranged on the inner side of the side wall opposite to the limit card slot. One end of the elastic member facing the limit card slot is connected with a limit post 43. A card joint adapted to the shape of the limit card slot is arranged at one end of the limit post 43 close to the limit card slot. The main body part of the limit post 43 is set to have an increased cross-section relative to the card joint. The elastic member is in a compressed state, so that the card joint of the limit post 43 can extend out of the limit card slot, while the main body part of the limit post 43 is stuck in the telescopic cavity of the fixed section 41. At the same time, limit card slots with the same shape and size are arranged at both ends of the corresponding side walls of the telescopic section 42 connected to the fixed section 41. By adjusting the position of the telescopic section 42, the limit slots 12 on the telescopic section 42 and the limit slots 12 on the fixed section 41 form a through hole, so that the card joint passes through the two limit slots 12 to realize the positioning connection between the telescopic section 42 and the fixed section 41. At the same time, by pressing the card joint to retract it into the fixed part, the position of the telescopic section 42 can be adjusted. Similarly, when there are multiple telescopic sections 42, the positioning connection between the telescopic sections 42 also adopts the same method, which will not be elaborated here. Through the above technical solution, the convenient and flexible adjustment of the length of the adjustable cover plate 4 is realized.

[0039] Furthermore, in the embodiment of the present application, as Figure 1As shown, the roof wind shaft opening anti-fall device also includes a sliding limit assembly 5, which includes an arc-shaped tooth 51 and a limit pull rod 52 connected to the arc-shaped tooth 51. The winding roller 31 is also provided with a limit groove 12 extending along its circumference. The limit pull rod 52 is slidably arranged in the limit groove 12, and can drive the arc-shaped tooth 51 to slide along the inner wall of the winding roller 31 to engage with the anti-fall net 2. Specifically, the curvature of the arc-shaped tooth 51 is adapted to the curvature of the inner wall of the winding roller 31. When the limit pull rod 52 slides along the limit groove 12, it can drive the anti-fall net 2 close to the unfolded anti-fall net 2 and penetrate into the mesh of the anti-fall net 2 to fix the anti-fall net 2, and prevent it from further unfolding or winding during use, which affects the protective performance of the anti-fall net 2.

[0040] Furthermore, in the above embodiment, if Figure 1 , Figure 2 , Figure 4 As shown, the sliding limit assembly 5 also includes a limit stopper 54 and an arc-shaped limit plate 53. The limit stopper 54 is arranged relative to the inner wall of the reel 1 on one side of the opening 11. The limit stopper 54 is provided with an arc-shaped groove, and both ends of the arc-shaped limit plate 53 are embedded in the arc-shaped groove; the arc-shaped teeth 51 are evenly arranged on the side of the arc-shaped limit plate 53 close to the opening 11, and the limit pull rod 52 is connected to the arc-shaped limit plate 53. Specifically, the arc-shaped limit plate 53 has an arc-shaped plate of a set length and a set curvature, which is fixed to the inner wall of the reel 1 by a limit stopper 54; the limit stopper 54 is provided with an arc-shaped slot adapted to the arc-shaped limit plate 53. Preferably, the openings 11 of the arc-shaped slots of the two limit stops 54 are arranged relatively to each other, and the two ends of the arc-shaped limit plate 53 are respectively inserted into the arc-shaped slots, and the limit pull rod 52 is arranged on the arc-shaped limit plate 53. By pulling the arc-shaped limit plate 53 to move in the limit groove 12, the arc-shaped limit plate 53 can be driven to slide in the arc-shaped slot, thereby driving the arc-shaped tooth 51 to move toward the unfolded anti-fall net 2 to clamp the anti-fall net 2; it should be noted that the limit groove 12 has a set length, so that the limit pull rod 52 can only move within this length range, thereby limiting the moving range of the arc-shaped limit plate 53 and the arc-shaped tooth 51 to prevent the arc-shaped limit plate 53 from being separated from the arc-shaped slot, thereby ensuring its limiting function.

[0041] In the above embodiment, the arc-shaped tooth 51 moves toward the opening 11 driven by the limiting pull rod 52 and the arc-shaped limiting plate 53, and engages with the anti-fall net 2 at the opening 11; the moving range of the arc-shaped limiting plate 53 and the length of the arc-shaped tooth 51 are matched, so that the end of the arc-shaped tooth 51 away from the arc-shaped limiting plate 53 can extend to the opposite side of the opening 11.

[0042] Preferably, the limiting pull rod 52 is provided with a locking member which is threadedly connected to the part of the limiting pull rod 52 extending outside the winding drum 1. By screwing the locking member, the locking member can be made to abut against the outer wall of the winding drum 1 to realize the limitation of the limiting pull rod 52, so as to prevent the arc-shaped teeth 51 from moving during use and ensure the stable limitation of the anti-falling net 2 by the arc-shaped teeth 51.

[0043] In the above embodiment, the distance between the arc-shaped teeth 51 is adapted to the mesh holes of the anti-falling net 2. Along the width direction of the anti-falling net 2, several arc-shaped teeth 51 are arranged in the mesh holes of the anti-falling net 2, and the anti-falling net 2 can be stably fixed at the opening 11 of the winding drum 1.

[0044] In the embodiment of the present application, the construction method of the above-mentioned roof air shaft opening anti-falling device includes the following steps:

[0045] S1. Place the winding drum 1 outside the well wall of the roof air shaft so that both ends of the winding drum 1 are attached to the upright posts 6 of the roof air shaft;

[0046] Specifically, usually the well wall of the roof air shaft is set higher than the roof, and there is an upright post 6 at each of the four corners of the well wall. The top of the upright post 6 is provided with an air shaft ceiling; in this embodiment, both ends of the winding drum 1 are respectively attached to the side walls of two upright posts 6 away from the air shaft opening;

[0047] S2. Pull the handle 44 to unfold the anti-falling net 2 so that the adjustable cover plate 4 extends to the outside of the well wall on the other side;

[0048] S3. Adjust the elongation of the adjustable cover plate 4 so that both ends of the adjustable cover plate 4 are stuck on the upright posts 6 on the other side;

[0049] Specifically, the unfolded anti-falling net 2 is laid on the well wall of the air shaft and extends from one side of the air shaft opening to the opposite side; the end face of the adjustable cover plate 4 connected to the anti-falling net 2 is clamped with the side wall of the upright post 6 away from the air shaft opening; in order to achieve the clamping installation, the tightness of the anti-falling net 2 can be adjusted by adjusting the rocker 32 so that both the winding drum 1 and the adjustable cover plate 4 are stuck on the side wall of the upright post 6 away from the air shaft opening;

[0050] S4. Lock the anti-falling net 2 through the sliding limiting assembly 5;

[0051] When both the winding drum 1 and the adjustable cover plate 4 are clamped, by pulling the limiting pull rod 52, the arc-shaped limiting plate 53 and the arc-shaped teeth 51 are driven to move, so that the arc-shaped teeth 51 clamp the anti-falling net 2, and then the limiting pull rod 52 is fixed by the locking member;

[0052] S5. After the construction is completed, unlock the anti-falling net 2 through the sliding limiting assembly 5, adjust the adjustable cover plate 4 to contract, and wind up the anti-falling net 2 through the rocker 32 so that the adjustable cover plate 4 is buckled on the winding drum 1.

[0053] The advantages and positive effects of the present invention are:

[0054] (1) By setting up a winding drum and an adjustable cover plate, not only is the anti-falling net convenient for storage, but it can also be stably and conveniently fixed on the roof air shaft. At the same time, the shape of the anti-falling net can be limited to prevent entanglement and knotting during long-term use, ensuring the protective effect of the anti-falling net.

[0055] (2) After the construction of the device is completed, it can be conveniently removed as a whole. This not only improves the installation and removal efficiency of the windfall prevention device, reduces the operation difficulty, but also enables the overall device to be recycled, reducing the construction cost.

[0056] (3) The anti-falling net is a flexible metal net, with good flexibility, plasticity and rigidity, providing a reliable protective effect; the overall structure is compact, reducing space occupation and facilitating transportation and storage.

[0057] The above has described the embodiments of the present invention in detail, but the content described is only the preferred embodiments of the present invention and cannot be considered as used to limit the scope of implementation of the present invention. All equivalent changes and improvements made according to the scope of the application of the present invention should still fall within the scope covered by the patent of the present invention.

Claims

1. A roof air shaft opening anti-falling device, characterized in that: It includes a winding drum, a winding assembly, a fall-preventing net, and an adjustable cover plate; a receiving space is provided inside the winding drum, and an opening is provided in the middle of the winding drum in the length direction; the winding assembly includes a winding roller and a rocker, the winding roller is rotatably arranged in the receiving space, the rocker is arranged outside the winding drum and connected to the winding roller; one end of the fall-preventing net is wound around the winding roller, and the other end is connected to the adjustable cover plate; the adjustable cover plate is snap-connected to the opening, and its length is adjustable.

2. The anti-falling device for the roof air shaft opening according to claim 1, characterized in that: The fall-preventing net is a flexible metal net.

3. The roof air shaft opening anti-falling device according to claim 2, wherein: The winding drum is a hollow cylinder, including an arc surface and end plates arranged at both ends of the arc surface, the opening is arranged on the arc surface; both ends of the winding roller are rotatably connected to the end plates; at least one end of the winding roller extends out of the end plate and is connected to the hand rocker.

4. The anti-falling device for the roof air shaft opening according to any one of claims 1-3, characterized in that: The adjustable cover plate includes a fixed section and telescopic sections connected to both ends of the fixed section, the shape of the fixed section is adapted to the opening, and a telescopic cavity for accommodating the telescopic sections is provided; the fall-preventing net is connected to the fixed section, and a handle is provided at one end of the fixed section opposite to the fall-preventing net.

5. The roof air shaft opening anti-falling device according to claim 4, characterized in that: Both the fixed section and the telescopic sections are square pipe bodies; several telescopic sections are nested and connected in sequence.

6. The anti-falling device for the roof air shaft opening according to claim 5, characterized in that: The adjustable cover plate further includes a limit post and a limit card slot; the limit card slot is arranged on the corresponding side walls of the fixed section and the telescopic sections, the limit post is abutted in the limit card slot through an elastic member, and the elastic member is arranged inside the telescopic section.

7. The anti-falling device for the roof air shaft opening according to claim 1 or 6, characterized in that: It further includes a sliding limit assembly, the sliding limit assembly includes an arc-shaped tooth and a limit pull rod connected to the arc-shaped tooth, the winding roller is further provided with a limit groove extending along its circumferential direction, the limit pull rod is slidably arranged in the limit groove, and can drive the arc-shaped tooth to slide along the inner wall of the winding roller to be clamped with the fall-preventing net.

8. The anti-falling device for the roof air shaft opening according to claim 7, wherein: The sliding limit assembly further includes a limit stop and an arc-shaped limit plate, the limit stops are oppositely arranged on one side of the opening close to the limit groove, the limit member is provided with an arc-shaped card slot, and both ends of the arc-shaped limit plate are embedded in the arc-shaped card slot; the arc-shaped teeth are evenly arranged on one side of the arc-shaped limit plate close to the opening, and the limit pull rod is connected to the arc-shaped limit plate.

9. The roof air shaft opening anti-falling device according to claim 8, wherein: The distance between the arc-shaped teeth is adapted to the mesh holes of the fall-preventing net.

10. The construction method of the anti-falling device for the roof air shaft opening according to any one of claims 1-9, characterized in that, It includes the following steps: Place the winding drum outside the well wall of the roof air shaft so that both ends of the winding drum are attached to the columns of the roof air shaft; Pull the handle to unfold the fall-preventing net so that the adjustable cover plate extends to the outside of the well wall on the other side; Adjust the elongation of the adjustable cover plate so that both ends of the adjustable cover plate are stuck on the columns on the other side; Lock the fall-preventing net through the sliding limit assembly; After the construction is completed, unlock the fall-preventing net through the sliding limit assembly, adjust the contraction of the adjustable cover plate, wind up the fall-preventing net through the rocker, and make the adjustable cover plate snap onto the winding drum.

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