Fabricated structure of existing building reconstruction extension space

Abstract

The invention belongs to the technical field of building prefabricated parts, particularly relates to a fabricated structure of an external extension space for existing building transformation, and provides the following scheme aiming at the problems that in the prior art, the external extension space needs to be greatly transformed on an existing external vertical face, so that time is wasted, and the environment is polluted. Comprising a main supporting plate which is fixed to the outer vertical face of a window through a main expansion bolt and located at the lower edge of the window, the main supporting plate is of an L-shaped structure as a whole, a vertical plate of the main supporting plate is fixed to the wall face, and the end, away from the outer vertical face of the window, of the main supporting plate is rotationally connected with an extending folding plate; locking rings are arranged on the two opposite sides, away from the hinge point, of the extending folding plate and close to the hinge point. According to the device, the production difficulty of the device is reduced, in the installation process, the main body of the device can be fixed only by using the main expansion bolts on the window outer vertical face below the window, and the extending folding plates can be rapidly unfolded when wind power is small so that the usable area can be increased.

Description

Technical Field

[0001] The invention relates to the technical field of building prefabricated parts, and in particular to an assembled structure for renovating and expanding the space of an existing building. Background Art

[0002] Existing building renovation and space expansion usually refers to increasing or expanding the usable space of a building through technical means, design innovation, etc. on the basis of the existing building. It is usually done by renovating, adding or adjusting the structure of the building's exterior to meet new functional requirements or improve the building's efficiency. Among them, extending the building's facade usually increases the space by adding certain external structural elements. For example, by expanding windows, walls or roof structures outwards, more internal usable space can be created.

[0003] After searching, it was found that in the prior art, when adding such an external expansion space structure, in order to increase the load-bearing capacity of the structure, it is necessary to make major modifications to the existing facades or heavy columns, which will inevitably increase the difficulty and construction period of the construction, and such modifications will also cause a lot of dust and noise, and are not suitable for rapid installation. Therefore, we propose a new type of assembled external expansion space structure that can be quickly installed. Summary of the invention

[0004] In view of the technical problem that the external expansion space transformation set in the prior art requires a large transformation on the existing facade, which is time-consuming and pollutes the environment, the present invention adopts the following technical solutions: A prefabricated structure for renovating and expanding the space of an existing building, comprising a main support plate fixed to the window facade by main expansion bolts and located at the lower edge of the window, the main support plate being in an L-shaped structure as a whole, and the vertical plate of the main support plate being fixed to the wall, the end of the main support plate away from the window facade being rotatably connected to an extended folding plate; and locking rings are provided near the hinge point on two opposite sides of the extended folding plate away from the hinge point, the two opposite sides of the main support plate away from the hinge point are slidably connected to latch rods, and coaxial guide slide tubes are pre-buried on the two opposite sides of the main support plate, the guide slide tube on the same side is coaxial with the locking ring on the side of the extended folding plate after it is laid flat, and the end of the latch rod close to the extended folding plate can be inserted into the corresponding locking ring as the extended folding plate is laid flat.

[0005] Preferably, the main support plate is composed of a second steel mesh frame and a concrete surface, and the second steel mesh frame includes a folded mesh surface and strip metal plates welded to the bottom end of the vertical section of the folded mesh surface and distributed at equal distances; the strip metal plates are provided with multiple through holes for later passing the main expansion bolts to fix the device to the wall; the guide slide pipes are welded and fixed to the two ends of the folded mesh surface; and the side of the plane mesh of the folded mesh surface away from the vertical mesh is respectively fixed with mutually symmetrical matching hinges near the two ends.

[0006] Preferably, strip grooves are provided on the lower surface of the main support plate near all the strip metal plates to expose the internal strip metal plates for easy fixation and installation. After the expansion bolts are installed, the strip grooves can be sealed with mud to prevent the exposed main expansion bolts from rusting, thereby improving the durability of the device.

[0007] Preferably, a pad is fixed between the vertical plate of the main support plate and the vertical wall of the window facade, and the pad is provided with strip holes corresponding to the position and size of the strip metal plate. The pad can have a certain buffering effect to prevent wall defects caused by long-term disrepair, which in turn causes uneven force.

[0008] Preferably, a steel mesh frame is embedded inside the extended folding plate, and main hinge joints symmetrical to each other are welded on both ends of the steel mesh frame near the side of the main support plate, and the main hinge joints are hinged together with the mating hinge; a limiting column perpendicular to the upper surface of the extended folding plate is fixed near the edge on the upper surface of the main hinge joint, and a limiting groove matched with the limiting column is provided near the corner at one end of the main support plate away from the window facade; a limiting support plate extending to the lower surface of the extended folding plate is reserved at the bottom end of the mating hinge.

[0009] Preferably, protruding tensioning earrings are reserved at the two corners of the upper surface of the extended folding plate away from the main support plate; and expansion hooks are fixed on the surface of the window facade near the top of the window, and two steel wire ropes are fixed between the expansion hooks and the tensioning earrings on the side, and a tensioner is arranged between the top of the steel wire rope two and the expansion hook; the pulling force on the expansion bolts on the vertical surface of the main support plate can be reduced, thereby increasing the safety and stability of the device.

[0010] Preferably, a protruding extension is reserved on the vertical surface of the window facade near the top of the main support plate, and an L-shaped auxiliary tensioning prefabricated plate extending downward is clamped on the extension, and two self-locking screws parallel to each other and extending vertically downward are fixed to the bottom end of the auxiliary tensioning prefabricated plate; the main support plate is provided with through holes matching the self-locking screws near the vertical plate; the self-locking screws are passed through the through holes and are sleeved with clamping springs, and top nuts are provided under the clamping springs, which are screwed to the bottom end of the self-locking screw, and the top of the auxiliary tensioning prefabricated plate is fixed to the upper surface of the extension by an expansion bolt.

[0011] Preferably, spring grooves are provided on the opposite sides of the main support plate between the two guide slide tubes; and spring blocks are fixed to the circumferential outer wall of the latch rod near the spring groove, and a compression spring is fixed to the end of the spring block away from the main hinge joint; a vertical toggle rod is fixed to the circumferential outer wall of the end of the latch rod away from the main hinge joint; it can be kept in an inserted state at normal times, thereby increasing the stability of the device and improving the convenience and safety of operation.

[0012] Preferably, a fixing hook is fixed in the middle of the second steel wire rope. When the folding plate needs to be folded and extended, the locked latch rod only needs to be pulled out first and then the fixing hook is hooked to pull it toward the window.

[0013] Preferably, a rope-pulling mechanism is fixed to the ends of the auxiliary tensioning prefabricated panels, and the rope-pulling mechanism includes a U-shaped bracket fixed to the upper side of the extension and opening upward in a U-shaped structure, and side guard plates parallel to each other are fixed on both sides of the U-shaped bracket, and the same composite rope pulley is rotatably connected between the two side guard plates; the composite rope pulley includes a coaxial worm gear and a rope winding wheel; a top cover plate is fixed to the top of the U-shaped bracket, and a bearing is embedded on the top cover plate, and a worm that meshes with the worm gear is rotatably connected in the bearing; a steel cable rope 1 is wound around the worm gear, and a tensioning hook is fixed to the end of the steel cable rope 1 away from the worm gear; a rocker is fixed to the top of the worm; a rope through hole is opened on the top of the top cover plate; through the set rope-pulling mechanism, the bending of the steel wire rope 2 can be controlled from near the window, and then the extended folding plate can be folded up.

[0014] The beneficial effects of the present invention are: 1. By setting a prefabricated main support plate and a hinged extension folding plate, not only the production difficulty of the device is reduced, but also during installation, the main body of the device can be fixed with main expansion bolts on the window facade below the window, and the extension folding plate can be quickly unfolded when the wind is small to increase the available area, and the extension folding plate can be retracted when strong winds come to reduce wind resistance.

[0015] 2. By setting up the second steel mesh frame, not only the weather resistance of the main support plate can be improved, but also the rigidity and connection firmness of the contact between the main expansion bolt and the main support plate can be increased to prevent the contact point from deforming and falling off.

[0016] 3. By setting the limit support plate and the limit column, when the extended folding plate is laid flat, even without the cooperation of the latch rod and the locking ring, the extended folding plate can be prevented from continuing to rotate, thereby limiting the flip angle to less than 180 degrees.

[0017] 4. By setting up an auxiliary tensioning prefabricated plate with a tensioning spring, the main support plate can be tilted upward 2-3 degrees as a load-bearing buffer before bearing weight. After placing heavy objects on the main support plate, it can be flattened to reduce the tensile stress on the main expansion bolts. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the overall structure of an assembled structure for renovating and expanding an existing building space after installation, as proposed by the present invention; Figure 2 A side view of a prefabricated structure for renovating and expanding an existing building space proposed by the present invention; Figure 3 This is a schematic diagram of a three-dimensional structure of a main support plate in a prefabricated structure for renovating an existing building and expanding its space, as proposed by the present invention; Figure 4 A schematic diagram of the three-dimensional structure of a steel mesh skeleton of an assembled structure for renovating and expanding an existing building space proposed by the present invention; Figure 5 A schematic diagram of the three-dimensional structure of an extended folding plate of a prefabricated structure for renovating an existing building and expanding its space proposed by the present invention; Figure 6 A schematic diagram of the three-dimensional structure of a steel mesh frame 2 of an assembled structure for renovating and expanding an existing building space proposed by the present invention; Figure 7 An exploded diagram of a pull rope mechanism in an assembled structure for renovating and expanding an existing building space proposed by the present invention; Figure 8 This is a structural schematic diagram of an auxiliary tensioning prefabricated panel in an assembled structure for renovating and expanding an existing building space proposed by the present invention.

[0019] In the figure: 1, main support plate; 101, spring groove; 102, strip sink; 103, perforation; 2, tension earring; 3, latch rod; 4, locking ring; 5, main hinge joint; 6, limit groove; 7, compression spring; 8, toggle rod; 9, pad; 10, auxiliary tension prefabricated plate; 11, window facade; 12, expansion hook; 13, tensioner; 14, pull rope mechanism; 141, U-shaped bracket; 142, top cover plate ; 143. Tension hook; 144. Bearing; 145. Side guard plate; 146. Worm; 147. Composite rope pulley; 15. Steel cable rope one; 16. Fixed hook; 17. Steel wire rope two; 18. Extended folding plate; 181. Steel mesh frame one; 19. Clamping spring; 20. Top nut; 21. Self-locking screw; 22. Guide slide; 23. Matching hinge; 24. Strip metal plate; 25. Steel mesh frame two. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0021] Reference Figure 1-8, an assembled structure for renovating an existing building to expand its space, comprising a main support plate 1 fixed to a window facade 11 by main expansion bolts and located at the lower edge of the window, the main support plate 1 being an L-shaped structure as a whole, and a vertical plate of the main support plate 1 being fixed to a wall, an end of the main support plate 1 away from the window facade 11 being rotatably connected to an extended folding plate 18; and locking rings 4 are arranged near the hinge point on two opposite sides of the extended folding plate 18 away from the hinge point, latch rods 3 are slidably connected to the opposite sides of the main support plate 1 away from the hinge point, and coaxial guide slide tubes 22 are pre-buried on the opposite sides of the main support plate 1, and the guide slide tubes 22 on the same side Coaxial with the locking ring 4 on the side of the extended folding plate 18 after being laid flat, the end of the latch rod 3 close to the extended folding plate 18 can be inserted into the corresponding locking ring 4 as the extended folding plate 18 is laid flat; by providing a prefabricated main support plate 1 and a hinged extended folding plate 18, not only the production difficulty of the device is reduced, but also during installation, only the main expansion bolts are needed to fix the main body of the device on the window facade 11 below the window, and when the wind is small, the extended folding plate 18 can be quickly unfolded to increase the available area, and when strong winds come, the extended folding plate 18 can be retracted to reduce wind resistance.

[0022] Reference Figure 4 The main support plate 1 is composed of a steel mesh frame 25 and a concrete surface, and the steel mesh frame 25 includes a folded mesh surface and strip metal plates 24 welded to the bottom end of the vertical section of the folded mesh surface and distributed at equal distances; the strip metal plates 24 are each provided with a plurality of through holes for later passing the main expansion bolts to fix the device to the wall; the guide slide pipes 22 are welded and fixed to the two ends of the folded mesh surface; and the side of the plane mesh of the folded mesh surface away from the vertical mesh is respectively fixed with mutually symmetrical matching hinges 23 near both ends; by setting the steel mesh frame 25, not only the weather resistance of the main support plate 1 can be improved, but also the rigidity and connection firmness of the contact between the main expansion bolts and the main support plate 1 are increased to prevent the contact from deformation and falling off.

[0023] Among them, strip grooves 102 are opened on the lower surface of the main support plate 1 near all the strip metal plates 24; they are used to expose the internal strip metal plates 24 for easy fixation and installation. After the main expansion bolts are installed, the strip grooves 102 can be sealed with mud to prevent the exposed main expansion bolts from rusting, thereby improving the durability of the device.

[0024] Reference Figure 2 A pad 9 is fixed between the vertical plate of the main support plate 1 and the vertical wall of the window facade 11, and a strip hole corresponding to the position and size of the strip metal plate 24 is opened on the pad 9. The pad 9 can play a certain buffering effect to prevent wall defects caused by long-term disrepair, thereby preventing uneven force.

[0025] Reference Figure 4 A steel mesh frame 181 is embedded inside the extended folding plate 18, and main hinge joints 5 symmetrical to each other are welded at both ends of the steel mesh frame 181 near the side of the main support plate 1, and the main hinge joints 5 are hinged together with the matching hinge 23; a limit column perpendicular to the upper surface of the extended folding plate 18 is fixed near the edge on the upper surface of the main hinge joint 5, and a limit groove 6 compatible with the limit column is opened near the corner at the end of the main support plate 1 away from the window facade 11; a limit support plate extending to the lower surface of the extended folding plate 18 is reserved at the bottom end of the matching hinge 23; by setting the limit support plate and the limit column, when the extended folding plate 18 is laid flat, even without the cooperation of the latch rod 3 and the locking ring 4, the extended folding plate 18 can be prevented from continuing to rotate, thereby limiting the flip angle to less than 180 degrees.

[0026] Reference Figure 2 and Figure 6 , protruding tensioning earrings 2 are reserved at the two corners of the upper surface of the extended folding plate 18 away from the main support plate 1; and an expansion hook 12 is fixed on the surface of the window facade 11 near the top of the window, and a steel wire rope 17 is fixed between the expansion hook 12 and the tensioning earring 2 on the side, and a tensioner 13 is arranged between the top of the steel wire rope 17 and the expansion hook 12; the pulling force on the expansion bolts on the vertical surface of the main support plate 1 can be reduced, and the safety and stability of the device can be increased.

[0027] Reference Figure 1 and Figure 2 The vertical surface of the window facade 11 is reserved with a protruding extension near the top of the main support plate 1, and an L-shaped auxiliary tensioning prefabricated plate 10 extending downward is clamped on the extension. Two self-locking screws 21 that are parallel to each other and extend vertically downward are fixed to the bottom end of the auxiliary tensioning prefabricated plate 10; the main support plate 1 is provided with a through hole 103 that is compatible with the self-locking screw 21 near the vertical plate; the self-locking screw 21 passes through the through hole 103 and is sleeved with a tightening spring 19, and the tightening spring 19 is A top nut 20 is provided below the spring 19, and the top nut 20 is screwed to the bottom end of the self-locking screw 21. The top of the auxiliary tensioning prefabricated plate 10 is fixed to the upper surface of the extension through the expansion bolt; by providing the auxiliary tensioning prefabricated plate 10 with a tightening spring 19, the main support plate 1 can be tilted upward by 2-3 degrees as a load-bearing buffer before bearing weight. After placing heavy objects on the main support plate 1, it can be flattened to reduce the tensile stress on the main expansion bolts.

[0028] Reference Figure 1 , Figure 2 and Figure 4Spring grooves 101 are provided on the opposite sides of the main support plate 1 between the two guide slide tubes 22; and spring blocks are fixed to the circumferential outer wall of the latch rod 3 near the spring groove 101, and a compression spring 7 is fixed to the end of the spring block away from the main hinge joint 5; a vertical toggle rod 8 is fixed to the circumferential outer wall of the end of the latch rod 3 away from the main hinge joint 5; it can be kept inserted at ordinary times, thereby increasing the stability of the device and improving the convenience and safety of operation.

[0029] Reference Figure 2 A fixing hook 16 is fixed in the middle of the wire rope 17. When the folding plate 18 needs to be folded and extended, the locked latch rod 3 only needs to be pulled out first and then the fixing hook 16 is hooked and pulled toward the window.

[0030] Reference Figure 2 and Figure 7 The ends of the auxiliary tensioning prefabricated panels 10 are fixed with a pull rope mechanism 14, and the pull rope mechanism 14 includes a U-shaped bracket 141 fixed to the upper side of the extension and opening upward to form a U-shaped structure, and the two sides of the U-shaped bracket 141 are respectively fixed with side guard plates 145 parallel to each other, and the two side guard plates 145 are rotatably connected with the same composite rope wheel 147; the composite rope wheel 147 includes a coaxial worm wheel and a rope winding wheel; the top of the U-shaped bracket 141 is fixed with a top cover plate 142, and the top cover plate A bearing 144 is embedded on 142, and a worm 146 meshing with the worm wheel is rotatably connected in the bearing 144; a steel cable 15 is wound around the worm wheel, and a tensioning hook 143 is fixed to the end of the steel cable 15 away from the worm wheel; a rocker is fixed to the top of the worm 146; a rope through hole is opened at the top of the top cover plate 142; through the set rope pulling mechanism 14, the bending of the steel wire rope 17 can be controlled from near the window, and then the extended folding plate 18 can be folded up.

[0031] Before installing the device, first fix the two expansion hooks 12 at the determined positions, and then fix the tensioner 13 at the top of the wire rope 17 on the expansion hook 12; then stick the pad 9 on the installation position, mark the punching position, and then use an electric hammer to punch holes in the marked positions, and then use the main expansion bolts to fix the main support plate 1 and the pad 9 at the marked positions; after the main expansion bolts are installed, use mud or sealing glue to block the strip sink 102 to prevent the exposed main expansion bolts from rusting, thereby improving the durability of the device; then extend the extended folding plate 18 to a position flush with the surface of the main support plate 1; then release the toggle rod 8, at which time the latch rod 3 can insert the locking ring 4 to lock the two; by setting an auxiliary tensioning prefabricated plate 10 with a tightening spring 19, the main support plate 1 can be tilted upward by 2-3 degrees as a load-bearing buffer before bearing weight, and after a heavy object is placed on the main support plate 1, it is flattened to reduce the tensile stress on the main expansion bolts.

[0032] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. An assembled structure for renovating an existing building to expand its space, comprising a main support plate (1) fixed to the window facade (11) by main expansion bolts and located at the lower edge of the window, characterized in that: The main support plate (1) is in an L-shaped structure as a whole, and the vertical plate of the main support plate (1) is fixed on the wall. The end of the main support plate (1) away from the window facade (11) is rotatably connected to the extension folding plate (18); and the two opposite sides of the extension folding plate (18) away from the hinge point are both provided with locking rings (4) near the hinge point. The two opposite sides of the main support plate (1) away from the hinge point are both slidably connected to the latch rod (3), and the two opposite sides of the main support plate (1) are both pre-buried with coaxial guide slide tubes (22), the guide slide tube (22) on the same side is coaxial with the locking ring (4) on the side of the extension folding plate (18) after being laid flat, and the end of the latch rod (3) close to the extension folding plate (18) can be inserted into the corresponding locking ring (4) as the extension folding plate (18) is laid flat.

2. The prefabricated structure for renovating and expanding the space of an existing building according to claim 1, characterized in that: The main support plate (1) is composed of a second steel mesh frame (25) and a concrete surface, and the second steel mesh frame (25) includes a folded mesh surface and strip metal plates (24) welded to the bottom end of the vertical section of the folded mesh surface and distributed at equal distances; the strip metal plates (24) are each provided with a plurality of through holes for later passing main expansion bolts to fix the device to the wall; the guide slide pipes (22) are welded and fixed to the two ends of the folded mesh surface; and mutually symmetrical matching hinges (23) are respectively fixed to the side of the plane mesh of the folded mesh surface away from the vertical mesh and close to the two ends.

3. The prefabricated structure for renovating and expanding the space of an existing building according to claim 2, characterized in that: The lower surface of the main support plate (1) is provided with strip-shaped sinking grooves (102) near all the strip-shaped metal plates (24).

4. The prefabricated structure for renovating and expanding the space of an existing building according to claim 1, characterized in that: A pad (9) is fixed between the vertical plate of the main support plate (1) and the vertical wall surface of the window facade (11), and a strip hole corresponding to the position and size of the strip metal plate (24) is opened on the pad (9).

5. The prefabricated structure for renovating and expanding the space of an existing building according to claim 2, characterized in that: A steel mesh frame (181) is embedded inside the extended folding plate (18), and mutually symmetrical main hinge joints (5) are welded to the two ends of the steel mesh frame (181) on one side close to the main support plate (1), and the main hinge joints (5) are hinged together with the matching hinge (23); a limit column perpendicular to the upper surface of the extended folding plate (18) is fixed near the edge of the upper surface of the main hinge joint (5), and a limit groove (6) matched with the limit column is opened near the corner of the end of the main support plate (11) away from the window facade (11); and a limit support plate extending toward the lower surface of the extended folding plate (18) is reserved at the bottom end of the matching hinge (23).

6. The prefabricated structure for renovating and expanding the space of an existing building according to claim 5, characterized in that: The upper surface of the extended folding plate (18) is provided with protruding tensioning earrings (2) at two corners away from the main support plate (1); and an expansion hook (12) is fixed to the surface of the window facade (11) near the top of the window, and a second steel wire rope (17) is fixed between the expansion hook (12) and the tensioning earring (2) on the side where it is located, and a tensioner (13) is provided between the top end of the second steel wire rope (17) and the expansion hook (12).

7. The prefabricated structure for renovating and expanding the space of an existing building according to claim 6, characterized in that: A protruding extension is reserved on the vertical surface of the window facade (11) near the top of the main support plate (1), and an L-shaped auxiliary tensioning prefabricated plate (10) extending downward is clamped on the extension, and two self-locking screws (21) parallel to each other and extending vertically downward are fixed to the bottom end of the auxiliary tensioning prefabricated plate (10); a through hole (103) matching the self-locking screw (21) is opened near the vertical plate of the main support plate (1); the self-locking screw (21) is inserted through the through hole (103) and is sleeved with a locking spring (19), and a counter nut (20) is arranged below the locking spring (19), and the counter nut (20) is screwed to the bottom end of the self-locking screw (21), and the top of the auxiliary tensioning prefabricated plate (10) is fixed to the upper surface of the extension by an expansion bolt.

8. The prefabricated structure for renovating and expanding the space of an existing building according to claim 1, characterized in that: The two opposite sides of the main support plate (1) are provided with spring grooves (101) between the two guide slide tubes (22); a spring stopper is fixed to the circumferential outer wall of the latch rod (3) near the spring groove (101); a compression spring (7) is fixed to the end of the spring stopper away from the main hinge joint (5); and a vertical toggle rod (8) is fixed to the circumferential outer wall of the end of the latch rod (3) away from the main hinge joint (5).

9. The prefabricated structure for renovating and expanding the space of an existing building according to claim 1, characterized in that: A fixing hook (16) is fixed in the middle of the second steel wire rope (17).

10. The prefabricated structure for renovating and expanding the space of an existing building according to claim 9, characterized in that: The ends of the auxiliary tensioning prefabricated panels (10) are fixed with a rope pulling mechanism (14), and the rope pulling mechanism (14) comprises a U-shaped bracket (141) fixed to the upper side of the extension and opening upward to form a U-shaped structure, and side guard plates (145) parallel to each other are respectively fixed on both sides of the U-shaped bracket (141), and the two side guard plates (145) are rotatably connected to the same composite rope wheel (147); the composite rope wheel (147) comprises a coaxial worm wheel disc and a rope winding wheel; A top cover plate (142) is fixed to the top of the U-shaped bracket (141), a bearing (144) is embedded on the top cover plate (142), and a worm (146) meshing with the worm wheel is rotatably connected in the bearing (144); a steel cable (15) is wound around the worm wheel, and a tension hook (143) is fixed to the end of the steel cable (15) away from the worm wheel; a rocker is fixed to the top of the worm wheel (146); and a rope passing hole is opened at the top of the top cover plate (142).

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