A cast iron manhole cover with optimized ventilation

Abstract

This utility model discloses a cast iron manhole cover with optimized ventilation, comprising: a manhole base, on the top left side of which is integrally provided with a U-shaped protrusion structure, and an annular limiting groove with an open top on its inner side; and a manhole cover body, movably fitted within the annular limiting groove, with a hollow hole and multiple ventilation holes on its top, the multiple ventilation holes surrounding the central hole. This utility model, through a series of structures, achieves multi-point, large-area ventilation through multiple holes, combined with a synergistic application of solid slag filtration and interception, optimizing ventilation while ensuring stable application within the manhole. Furthermore, it utilizes a short-stroke unlocking or locking mechanism by rotating a screw at a locking position, and allows for direct pulling after unlocking, reducing the number of screw rotations required and improving opening and closing efficiency. The absence of exposed screws or other driving components prevents subsequent jamming due to solid slag and impurities, improving ease of use and long-term stability.

Description

Technical Field

[0001] This utility model relates to the field of cast iron manhole cover technology, specifically a cast iron manhole cover with optimized ventilation effect. Background Technology

[0002] Ductile iron manhole covers are a type of ductile iron product. Ductile iron undergoes spheroidization and inoculation treatment to obtain spheroidal graphite, effectively improving the mechanical properties of cast iron, particularly its plasticity and toughness. This results in strength higher than carbon steel, with overall performance approaching that of steel. Based on its superior performance, it has been successfully used to cast parts subject to complex stresses and requiring high strength, toughness, and wear resistance. Heating projects are a crucial link in urban infrastructure construction, ensuring heat supply for residents and industrial production. Valve wells, confined spaces, are key nodes in heating network systems, used to regulate and control the flow of media within the pipelines. In recent years, with increasing heating demand, the accumulation of heat and retention of harmful gases in valve wells due to equipment operation has become increasingly prominent, seriously affecting the safety and ease of operation of the underground working environment. To solve this problem, the structure of valve well covers needs to be optimized to improve ventilation and ease of opening. However, existing cast iron manhole covers mostly adopt a closed structure or a few simple holes, which are significantly insufficient in terms of air circulation.

[0003] Regarding the convenient opening of cast iron manhole covers, Chinese Patent Publication No. CN114108701A discloses a convenient ductile iron manhole cover and its opening and closing method. The method includes a manhole base, on which a manhole cover is mounted, with the cover movably connected to the base. An opening and closing mechanism is provided on the inner side of the base, allowing the cover to be opened and closed on the base. The cover is pushed out of the base by a lifting push rod, and an anti-misoperation opening and closing insert is inserted into the lower positioning groove, causing the inner drive handle to self-lock, thus opening the cover. The cover is then pulled closed on the base by the lifting push rod, and an anti-misoperation opening and closing insert is inserted into the upper positioning groove, causing the inner drive handle to self-lock, thus closing the cover. This method facilitates the opening and closing of the manhole cover without the need for external tools, providing convenience for users.

[0004] The aforementioned technology discloses a convenient ductile iron manhole cover that, through the exposed inner structure of a traction screw, transmission belt, pulley, lifting plate, and lifting push rod, allows the cover to be gradually driven upward or downward through rotation. However, in practical applications, the following drawbacks exist: 1. The method of using a rotating traction screw to lift and drive the manhole cover requires multiple rotations of the traction screw to complete the lifting operation, which is not only time-consuming but also inefficient. Furthermore, the exposed inner structure of the transmission belt, screw, and pulley makes it highly susceptible to blockage by solid impurities, severely affecting the stability of long-term use. 2. Although existing cast iron manhole covers typically have a few small holes, the ventilation area is small, and there is a lack of a synergistic filtration mechanism, making it difficult to ensure ventilation while maintaining stable application inside the manhole. Therefore, this application proposes a cast iron manhole cover with optimized ventilation to solve the above problems. Utility Model Content

[0005] The purpose of this invention is to provide a cast iron manhole cover with optimized ventilation to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a cast iron manhole cover with optimized ventilation, comprising:

[0007] The well base has a U-shaped protrusion on its top left side, and an annular limiting groove with an opening at the top is provided on its inner side.

[0008] The main body of the manhole cover is movably fitted in an annular limiting groove. Its top has a hollow hole and multiple ventilation holes, and the multiple ventilation holes surround the central hole. The annular limiting groove is used to stably support the main body of the manhole cover by utilizing the steps formed on its bottom inner wall.

[0009] The rotating seat is rotatably installed inside the U-shaped protruding structure and is fixedly connected to the left side of the manhole cover body; the rotating seat is provided for rotatably installing the left side of the manhole cover body.

[0010] The filter assembly is fixedly connected to the bottom of the manhole cover body; the central hole and multiple vent holes are used for ventilation inside the manhole cover, and the filter assembly is used to filter and intercept solid impurities that enter from the outside.

[0011] The threaded horizontal locking and limiting component is installed between the bottom right side of the manhole cover body and the inner wall of the right side of the manhole seat. A rectangular groove is provided on the top right side of the manhole cover body. Both ends of the threaded horizontal locking and limiting component are rotatably installed with the same U-shaped handle located in the rectangular groove. The threaded horizontal locking and limiting component is used to lock and unlock the manhole cover body, and together with the U-shaped handle, it facilitates the easy pulling and opening of the manhole cover body by personnel.

[0012] Preferably, the filter assembly includes an internal threaded sleeve, an external threaded sleeve, a stainless steel filter screen, and a handle. The internal threaded sleeve is fixedly connected to the bottom of the manhole cover body, and the external threaded sleeve is threaded onto the internal threaded sleeve. A rubber ring that is tightly pressed against the bottom of the manhole cover body is bonded to the top of the external threaded sleeve. There are four handles, which are fixedly connected to the outside of the external threaded sleeve in a ring at equal intervals. The stainless steel filter screen is fixedly installed inside the external threaded sleeve.

[0013] Preferably, the threaded transverse retaining assembly includes a rectangular sleeve, a rectangular slider, a retaining block, a screw, a worm gear, a worm, and a crossbar. The rectangular sleeve is fixedly connected to the bottom right side of the manhole cover body, and the right side of the rectangular sleeve is set as an opening. The rectangular slider is slidably fitted inside the rectangular sleeve. The retaining block is fixedly connected to the right inner wall of the manhole cover. A rectangular protrusion structure is integrally provided on the bottom right side of the rectangular slider. The top of the rectangular protrusion structure is in movable contact with the bottom of the retaining block. The screw is rotatably installed on the left inner wall of the rectangular sleeve. The rectangular slider is threadedly fitted onto the screw. The worm gear is fixedly fitted onto the screw. The worm is rotatably embedded in the bottom right side of the manhole cover body and meshes with the rear side of the worm gear. The crossbar is located in a rectangular groove and is fixedly connected to the top of the worm. The two ends of the crossbar are rotatably connected to the inner walls of the two sides of the U-shaped handle, respectively.

[0014] Preferably, a rectangular through hole communicating with the U-shaped protrusion structure is provided on the left inner wall of the annular limiting groove. The top of the rectangular through hole is set as an opening, and the rotating seat is located inside the rectangular through hole and in movable contact with the inner wall of the rectangular through hole.

[0015] Preferably, a support shaft is fixedly connected between the front and rear inner walls of the U-shaped protrusion structure, the left side of the rotating seat is configured as an arc structure, a circular through hole is opened on the front side of the rotating seat, two first bearings are fixedly sleeved in the circular through hole, and the inner ring of the first bearing is fixedly sleeved with the outer side of the support shaft.

[0016] Preferably, the rectangular slider has a threaded groove on its left side that is threaded to connect with the screw.

[0017] Preferably, a limiting hole is provided on the top inner wall of the rectangular sleeve, and a limiting block that is slidably connected to the top of the rectangular slider is fixedly connected to the limiting hole.

[0018] Compared with the prior art, the beneficial effects of this utility model are:

[0019] 1. By combining the main body of the manhole cover, multiple ventilation holes, a central hole, and a filter assembly, the multi-point large-area ventilation formed by the multiple holes, combined with the filtering and interception of incoming solid slag, facilitates stable application inside the well while optimizing the ventilation effect.

[0020] Furthermore, after the main body of the manhole cover is opened, the stainless steel filter screen can be disassembled and cleaned of solids by simple rotation, which facilitates the subsequent cleaning and replacement of filter components.

[0021] 2. Through the combination of the manhole cover body, manhole base, U-shaped protruding structure, threaded horizontal locking and limiting component, U-shaped handle and rotating seat, the screw is rotated only at the locking position for short-stroke unlocking or locking. Combined with the method of directly pulling to open after unlocking, the number of screw rotations required is reduced, improving opening and closing efficiency. Moreover, there are no exposed screws or other driving components inside, avoiding the phenomenon of jamming caused by solid slag and impurities, thus improving ease of use and long-term application stability.

[0022] This utility model, through a series of structures, enables multi-point, large-area ventilation formed by multiple holes, combined with the synergistic application of solid slag filtration and interception. It optimizes ventilation while ensuring stable application inside the well. Furthermore, it utilizes a short-stroke unlocking or locking mechanism by rotating the operating screw at the locking position, and the method of directly pulling to open after unlocking reduces the number of screw rotations required, improving opening and closing efficiency. Moreover, the absence of exposed screws or other driving components inside avoids subsequent jamming caused by solid slag and impurities, thus improving ease of use and long-term application stability. Attached Figure Description

[0023] Figure 1 This is a structural schematic diagram of a cast iron manhole cover with optimized ventilation effect proposed in this utility model;

[0024] Figure 2 This is a schematic diagram of the main sectional view of a cast iron manhole cover with optimized ventilation effect proposed in this utility model.

[0025] Figure 3 for Figure 2 A magnified structural diagram of part A in the diagram.

[0026] In the diagram: 1. Manhole base; 101. U-shaped protruding structure; 102. Annular limiting groove; 2. Manhole cover body; 201. Vent hole; 202. Rotating seat; 3. Internal threaded sleeve; 301. External threaded sleeve; 302. Stainless steel filter screen; 4. Rectangular sleeve; 401. Rectangular slider; 402. Locking block; 403. Screw; 404. Worm gear; 405. Worm; 406. Crossbar; 407. U-shaped handle. Detailed Implementation

[0027] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0028] like Figures 1 to 3 As shown in the figure, this embodiment proposes a cast iron manhole cover with optimized ventilation effect, comprising:

[0029] The well base 1 has a U-shaped protruding structure 101 integrally provided on the top left side, and an annular limiting groove 102 with an open top is provided on its inner side.

[0030] The manhole cover body 2 is movably fitted in the annular limiting groove 102. Its top has a hollow hole and multiple ventilation holes 201, which surround the central hole. The annular limiting groove 102 is used to stably support the manhole cover body 2 by utilizing the steps formed on its bottom inner wall.

[0031] The rotating seat 202 is rotatably installed inside the U-shaped protruding structure 101 and is fixedly connected to the left side of the manhole cover body 2; the rotating seat 202 is provided for rotatably installing the left side of the manhole cover body 2.

[0032] The filter assembly is fixedly connected to the bottom of the manhole cover body 2; the central hole and multiple ventilation holes 201 are provided for ventilation inside the manhole cover 1, and the filter assembly is used to filter and intercept solid impurities entering from the outside.

[0033] The threaded horizontal locking and limiting component is installed between the bottom right side of the manhole cover body 2 and the inner wall of the right side of the manhole seat 1. A rectangular groove is provided on the top right side of the manhole cover body 2. Both ends of the threaded horizontal locking and limiting component are rotatably mounted with the same U-shaped handle 407 located in the rectangular groove. The threaded horizontal locking and limiting component is used to lock and unlock the manhole cover body 2, and together with the U-shaped handle 407, it facilitates the easy pulling and opening of the manhole cover body 2 by personnel.

[0034] In this embodiment, a rectangular through hole communicating with the U-shaped protrusion 101 is provided on the left inner wall of the annular limiting groove 102. The top of the rectangular through hole is set as an opening. The rotating seat 202 is located in the rectangular through hole and is in movable contact with the inner wall of the rectangular through hole, so as to allow the rotating seat 202 to pass through. A support shaft is fixedly connected between the front and rear inner walls of the U-shaped protrusion 101. The left side of the rotating seat 202 is set as an arc structure. A circular through hole is provided on the front side of the rotating seat 202. Two first bearings are fixedly sleeved in the circular through hole. The inner ring of the first bearing is fixedly sleeved with the outer side of the support shaft. The support shaft and the first bearings serve to rotate the rotating seat 202.

[0035] Furthermore, such as Figure 2As shown, the filter assembly includes an inner threaded sleeve 3, an outer threaded sleeve 301, a stainless steel filter screen 302, and a handle. The inner threaded sleeve 3 is fixedly connected to the bottom of the manhole cover body 2. The outer threaded sleeve 301 is threaded onto the inner threaded sleeve 3. A rubber ring that is pressed tightly against the bottom of the manhole cover body 2 is bonded to the top of the outer threaded sleeve 301. There are four handles, which are fixedly connected to the outside of the outer threaded sleeve 301 in a ring with equal spacing. The stainless steel filter screen 302 is fixedly installed inside the outer threaded sleeve 301.

[0036] In this implementation scheme, the internal threaded sleeve 3, external threaded sleeve 301, stainless steel filter screen 302, and handle are used together. After external solid slag enters or follows rainwater through the central hole and multiple ventilation holes 201, the stainless steel filter screen 302 filters, intercepts, and collects the solid impurities inside the external threaded sleeve 301. This achieves the effect of filtering and intercepting external solid impurities, preventing a large amount of solid impurities from flowing deep into the well and causing blockage of the internal pipes. When cleaning the solid slag inside the well cover body 2 by rotating it, the operator pulls the handle in the opposite direction to drive the external threaded sleeve 301 to rotate. The external threaded sleeve 301 rotates inside the internal threaded sleeve 3 and gradually separates from it, allowing the external threaded sleeve 301 to be removed and the solid slag impurities inside to be poured out for cleaning. This achieves the effect of conveniently disassembling and cleaning the stainless steel filter screen 302 by simply rotating it.

[0037] Furthermore, such as Figure 2 and 3 As shown, the threaded transverse retaining assembly includes a rectangular sleeve 4, a rectangular slider 401, a retaining block 402, a screw 403, a worm gear 404, a worm 405, and a crossbar 406. The rectangular sleeve 4 is fixedly connected to the bottom right side of the manhole cover body 2. The right side of the rectangular sleeve 4 is set as an opening. The rectangular slider 401 is slidably fitted inside the rectangular sleeve 4. The retaining block 402 is fixedly connected to the inner wall of the right side of the manhole base 1. A rectangular protruding structure is integrally provided on the bottom right side of the rectangular slider 401. The top of the rectangular protruding structure... The bottom of the part is in contact with the bottom of the locking block 402. The screw 403 is rotatably installed on the left inner wall of the rectangular sleeve 4. The rectangular slider 401 is threaded on the screw 403. The worm gear 404 is fixedly installed on the screw 403. The worm 405 is rotatably embedded in the bottom right side of the well cover body 2 and meshes with the rear side of the worm gear 404. The crossbar 406 is located in the rectangular groove and is fixedly connected to the top of the worm 405. The two ends of the crossbar 406 are rotatably connected to the inner walls of the two sides of the U-shaped handle 407 respectively.

[0038] In this embodiment, a threaded groove is provided on the left side of the rectangular slider 401, which is threadedly connected to the screw 403. The threaded connection between the screw 403 and the threaded groove facilitates the lateral displacement of the rectangular slider 401 when the screw 403 rotates. A limit hole is provided on the top inner wall of the rectangular sleeve 4, and a limit block is fixedly connected to the top of the rectangular slider 401, which is slidably connected to the limit hole, thus limiting and preventing the rectangular slider 401 from detaching. A second bearing is fixedly connected to the left inner wall of the rectangular sleeve 4, and the inner side of the inner ring of the second bearing is fixedly connected to the outer side of the screw 403, thus enabling the screw 403 to be rotated and installed. A through hole is provided on the bottom right side of the manhole cover body 2 and the top inner wall of the rectangular sleeve 4, which is connected to the rectangular groove. A sealed bearing is fixedly fitted in the through hole, and the inner ring of the sealed bearing is fixedly fitted to the outer side of the worm gear 405, thus enabling the worm gear 405 to be rotated and installed.

[0039] In this implementation scheme, the rectangular sleeve 4, rectangular slider 401, locking block 402, screw 403, worm gear 404, worm 405, and crossbar 406 work together. The locking block 402 blocks the rectangular protruding structure, allowing the rectangular slider 401 and rectangular sleeve 4 to sequentially lock and secure the manhole cover body 2, preventing it from automatically opening due to vibration, water erosion, or other factors, thus ensuring stability when closed. When it needs to be opened for internal inspection and cleaning, personnel first pull the U-shaped handle 407 to rotate it upwards to a vertical position, then rotate the U-shaped handle 407 in the opposite direction, causing the crossbar 406 to drive the worm 405 to rotate. The worm 405 drives the meshing worm gear 404 to rotate, which in turn drives the screw 403 to rotate. The rotation of the screw 403 causes the rectangular slider 401 to slide to the left within the rectangular sleeve 4, and the rectangular slider 401 drives the rectangular protruding structure... The structure separates from the locking block 402 to the left, releasing the locking restriction. The U-shaped handle 407 can then be pulled upwards to rotate the manhole cover body 2 upwards and open it via the crossbar 406 and worm gear 405. When closing, rotate the handle downwards to close the manhole cover body 2, then rotate the U-shaped handle 407 in the forward direction. Similarly, the movement direction of the U-shaped handle 407 is completely opposite to the reverse rotation mentioned above. At this time, the rectangular slider 401 moves to the right and drives the rectangular protruding structure to lock onto the bottom of the locking block 402, thus locking the manhole cover body 2. This achieves the effect of conveniently opening and closing the manhole cover body 2 by rotating the U-shaped handle 407. The U-shaped handle 407 also allows for easy pulling and opening of the manhole cover body 2, improving ease of use. After use, rotate the U-shaped handle 407 longitudinally into the rectangular groove.

[0040] It should be noted that the internal threaded sleeve 3, external threaded sleeve 301, support shaft, rotating seat 202, U-shaped handle 407, rectangular sleeve 4, rectangular slider 401, locking block 402, screw 403, worm gear 404, worm 405 and crossbar 406 are all made of stainless steel. The advantages of stainless steel, such as high hardness, high wear resistance and good maintenance-free effect, are utilized to ensure long-term connection and driving stability.

[0041] The method of use in this embodiment is as follows: When the cast iron manhole cover with optimized ventilation is used, the central hole and multiple ventilation holes 201 work together to form a multi-point ventilation effect for a large area inside the manhole base 1. After external solid slag enters or follows rainwater into the manhole through the central hole and multiple ventilation holes 201, the solid impurities are filtered, intercepted, and collected in the external threaded sleeve 301 by the stainless steel filter screen 302. This achieves the effect of filtering and intercepting external solid impurities, avoiding the phenomenon of a large amount of solid impurities flowing into the depths of the manhole and causing blockage of the internal pipes. The multi-point large-area ventilation formed by the multiple holes, combined with the filtering and interception of the entering solid slag, facilitates stable application in the manhole while optimizing the ventilation effect.

[0042] The rectangular protruding structure is blocked by the locking block 402, which sequentially locks the manhole cover body 2 through the rectangular slider 401 and the rectangular sleeve 4, preventing it from opening automatically due to vibration, water erosion, or other factors, and ensuring stability when closed. When it needs to be opened for internal maintenance and cleaning, the operator first pulls the U-shaped handle 407 to rotate it upwards to a vertical position, then rotates the U-shaped handle 407 in the opposite direction, causing the worm gear 405 to rotate via the crossbar 406. The worm gear 405 then rotates the meshing worm wheel 404, which in turn rotates the screw 403. The rotation of the screw 403 causes the rectangular slider 401 to slide to the left within the rectangular sleeve 4. The rectangular slider 401 causes the rectangular protruding structure to separate from the locking block 402 to the left, releasing the locking restriction. The operator can then directly pull the U-shaped handle 407 upwards, causing the manhole cover body 2 to rotate upwards and open sequentially via the crossbar 406 and the worm gear 405. When closing after use, the manhole cover body 2 is closed by rotating it downwards. Then, rotate the U-shaped handle 407 in the forward direction. Similarly, the movement direction is completely opposite to that of rotating the U-shaped handle 407 in the reverse direction. At this time, the rectangular slider 401 changes to move back to the right and drives the rectangular protruding structure to lock to the bottom of the locking block 402, thereby locking and restricting the manhole cover body 2. This achieves the effect of conveniently opening and closing the manhole cover body 2 by rotating the U-shaped handle 407. The U-shaped handle 407 also makes it convenient for personnel to pull the manhole cover body 2 to open. After use, the U-shaped handle 407 can be rotated longitudinally into the rectangular groove. The screw 403 is rotated only in the locking position for short-stroke unlocking or locking. Combined with the method of directly pulling to open after unlocking, the number of rotations of the screw 403 is reduced, improving the opening and closing efficiency. Moreover, there are no exposed screw 403 or other driving components inside, which avoids the phenomenon of jamming caused by solid slag and impurities. This improves the ease of use and long-term application stability.

[0043] In addition, when the main body 2 of the manhole cover is opened and the solid slag collected by the filter needs to be cleaned, the personnel pull the handle in the opposite direction to drive the external threaded sleeve 301 to rotate. The external threaded sleeve 301 rotates inside the internal threaded sleeve 3 and gradually separates from it, so that the external threaded sleeve 301 can be removed and the solid slag and impurities inside can be poured out for cleaning. After cleaning, the external threaded sleeve 301 is rotated in the forward direction and tightened into the internal threaded sleeve 3. This achieves the effect of conveniently disassembling and cleaning the solid slag of the stainless steel filter screen 302 by simply rotating it.

[0044] Finally, it should be noted that the above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A cast iron manhole cover with optimized ventilation effect, comprising a manhole base (1), characterized in that: include: The well base (1) has a U-shaped protruding structure (101) integrally provided on the top left side, and an annular limiting groove (102) with an opening at the top is provided on its inner side. The main body of the manhole cover (2) is movably fitted in the annular limiting groove (102), and its top is provided with a hollow hole and multiple ventilation holes (201), and the multiple ventilation holes (201) surround the central hole; The rotating seat (202) is rotatably installed in the U-shaped protruding structure (101) and fixedly connected to the left side of the manhole cover body (2); The filter assembly is fixedly connected to the bottom of the manhole cover body (2); The threaded horizontal clamping and limiting assembly is installed between the bottom right side of the manhole cover body (2) and the right inner wall of the manhole seat (1). A rectangular groove is provided on the top right side of the manhole cover body (2). Both ends of the threaded horizontal clamping and limiting assembly are rotatably installed with the same U-shaped handle (407) located in the rectangular groove.

2. The cast iron manhole cover with optimized ventilation effect according to claim 1, characterized in that: The filter assembly includes an inner threaded sleeve (3), an outer threaded sleeve (301), a stainless steel filter screen (302), and a handle. The inner threaded sleeve (3) is fixedly connected to the bottom of the manhole cover body (2). The outer threaded sleeve (301) is threaded onto the inner threaded sleeve (3). A rubber ring that is pressed tightly against the bottom of the manhole cover body (2) is bonded to the top of the outer threaded sleeve (301). There are four handles that are fixedly connected to the outside of the outer threaded sleeve (301) in a ring with equal spacing. The stainless steel filter screen (302) is fixedly installed inside the outer threaded sleeve (301).

3. The cast iron manhole cover with optimized ventilation effect according to claim 1, characterized in that: The threaded transverse retaining assembly includes a rectangular sleeve (4), a rectangular slider (401), a retaining block (402), a screw (403), a worm gear (404), a worm (405), and a crossbar (406). The rectangular sleeve (4) is fixedly connected to the bottom right side of the manhole cover body (2). The right side of the rectangular sleeve (4) is set as an opening. The rectangular slider (401) is slidably fitted inside the rectangular sleeve (4). The retaining block (402) is fixedly connected to the inner wall of the right side of the manhole base (1). A rectangular protruding structure is integrally provided on the bottom right side of the rectangular slider (401). The top of the screw (403) is in contact with the bottom of the block (402). The screw (403) is rotatably mounted on the left inner wall of the rectangular sleeve (4). The rectangular slider (401) is threaded onto the screw (403). The worm gear (404) is fixedly mounted on the screw (403). The worm gear (405) is rotatably embedded in the bottom right side of the well cover body (2) and meshes with the rear side of the worm gear (404). The crossbar (406) is located in the rectangular groove and is fixedly connected to the top of the worm gear (405). The two ends of the crossbar (406) are rotatably connected to the inner walls of the two sides of the U-shaped handle (407).

4. The cast iron manhole cover with optimized ventilation effect according to claim 1, characterized in that: The left inner wall of the annular limiting groove (102) is provided with a rectangular through hole that communicates with the U-shaped protrusion structure (101). The top of the rectangular through hole is set as an opening, and the rotating seat (202) is located in the rectangular through hole and is in contact with the inner wall of the rectangular through hole.

5. A cast iron manhole cover with optimized ventilation effect according to claim 1, characterized in that: A support shaft is fixedly connected between the front and rear inner walls of the U-shaped protrusion structure (101). The left side of the rotating seat (202) is set as an arc structure. A circular through hole is opened on the front side of the rotating seat (202). Two first bearings are fixedly sleeved in the circular through hole. The inner ring of the first bearing is fixedly sleeved with the outer side of the support shaft.

6. A cast iron manhole cover with optimized ventilation effect according to claim 3, characterized in that: The rectangular slider (401) has a threaded groove on its left side that is threaded to the screw (403).

7. A cast iron manhole cover with optimized ventilation effect according to claim 3, characterized in that: A limiting hole is provided on the top inner wall of the rectangular sleeve (4), and a limiting block that is slidably connected to the top of the rectangular slider (401) is fixedly connected to the limiting hole.

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