CN107780439B

CN107780439B - Well lid assembly with adjustable base

Info

Publication number: CN107780439B
Application number: CN201610714752.3A
Authority: CN
Inventors: 董满林; 吴忠正; 韩红义
Original assignee: Shanxi Hantong Xinyu Technology Co ltd
Current assignee: Shanxi Hantong Xinyu Technology Co ltd
Priority date: 2016-08-24
Filing date: 2016-08-24
Publication date: 2021-04-16
Anticipated expiration: 2036-08-24
Also published as: CN107780439A

Abstract

The present invention provides a well lid assembly comprising: a base having a generally cylindrical body and a flange extending radially outwardly from one end of the body, at least one internal thread formed on an inner wall of the body; a lifting ring having a substantially cylindrical body and an enlarged diameter portion at one end of the body, the outer wall of the lifting ring body having at least three external threads formed thereon, the enlarged diameter portion forming an opening of the lifting ring; and a well lid for covering the opening, the body of the lift ring being mounted within the body of the base such that the external threads of the lift ring threadably engage the internal threads of the base to selectively cause the lift ring to move along the longitudinal axis relative to the base by rotation, wherein the well lid assembly further comprises a base track for engaging the cement base, the base track having a generally circular body and being mounted relative to the base track such that an angle of inclination of the base relative to the base track is adjustable by an adjustment device.

Description

Well lid assembly with adjustable base

Technical Field

The present invention relates generally to a manhole cover assembly, in particular for use in road construction, wherein the inclination of the base surface of the manhole cover assembly with respect to the base track can be adjusted as desired and is equipped with a quick-locking device.

Background

Well covers are widely used in urban road construction. Along with the continuous extension of urban construction, the quality requirement of laying the road surface is higher and higher, along with coming to also higher and higher the requirement to the well lid, the well lid flushes with ground as far as possible when requiring to lay.

In addition, in traditional road construction, after years of use, the road surface is likely to collapse, which causes unevenness between the well cover and the road surface, easily causes damage to vehicles, and also affects the beauty of the road surface. In addition, need renovate the road surface after using for many years, mostly need abandon current well lid completely to make again and install again at the in-process of laying again, waste time and energy and the cost is higher.

In addition, conventional well lids are rarely equipped with suitable locking means and are therefore prone to rattling up and down and producing noise as the vehicle passes over the well lid.

Therefore, there is a need for a manhole cover assembly that can easily adjust the height of the manhole cover and the angle of inclination of the manhole cover to perfectly fit the ground.

Disclosure of Invention

The present invention is directed to an improved manhole cover assembly that can easily adjust the height of the manhole cover and the angle of inclination of the manhole cover to perfectly match the ground.

To achieve the above object, the present invention provides a well lid assembly, comprising: a base having a generally cylindrical body with at least one internal thread formed on an inner wall thereof and a flange extending radially outwardly from one end of the body, the flange having an adjustment means thereon; a lifting ring having a generally cylindrical body and an enlarged diameter portion at one end of the body, the lifting ring having at least three external threads formed on an outer wall of the body, the enlarged diameter portion forming an opening of the lifting ring; and a well lid for covering the opening, the body of the lift ring being mounted within the body of the base such that the external threads of the lift ring threadably engage the internal threads of the base to selectively cause the lift ring to move along the longitudinal axis relative to the base upon rotation, wherein the well lid assembly further comprises a base track for engaging a cement base, the base track having a generally circular body, and the base being mounted relative to the base track such that the angle of inclination of the base relative to the base track is adjustable by the adjustment device on the flange of the base.

Preferably, the flange of the base is provided with a pair of threaded holes which are diametrically opposite to each other, and a pair of adjusting bolts are screwed in the axial direction to penetrate through the threaded holes, and when the base is installed on the base rail, the adjusting bolts can extend out of the threaded holes and abut against the upper surface of the base rail through screwing.

Preferably, the body of the base rail comprises an annular recess in the circumferential direction on the upper surface, against which the adjusting bolt rests and is received on the base rail when the base is mounted thereon.

Preferably, the lower surface of the flange of the base is provided with a pair of diametrically opposed radially extending grooves which face the annular groove when the base is mounted on the base rail, and two adjustment cylinders are each received in the grooves and the annular groove, respectively, so that the base can rotate relative to the base rail.

Preferably, at least three support blocks are formed on an upper surface of the internal thread of the base, the support blocks being uniformly spaced apart in a circumferential direction. Preferably, the support block has a height of about 1mm and a length in the circumferential direction of about 50 mm.

Preferably, at least three protrusions are provided on an outer circumferential surface of the enlarged diameter portion of the lifting ring, the protrusions being evenly spaced in a circumferential direction, the protrusions being in contact with a road material when the manhole cover assembly is installed on a road to relieve a load acting on the internal thread of the base and the external thread of the lifting ring.

Preferably, the base rail includes at least three fixing portions extending radially outward from a main body of the base rail and evenly spaced, the fixing portions being provided with fixing bolts, axial directions of the fixing bolts being parallel to a direction of a plane of the base rail, the fixing bolts being capable of extending inward beyond an outer circumference of a flange of the base by screwing when the base is mounted on the base rail to prevent the base from being detached from the base rail.

Preferably, the well lid assembly further comprises a locking device for releasably locking the lifting ring and the well lid together.

Preferably, the locking device includes a locking pin, a fixing pin and a spring, the locking pin includes a rod body and a head located at one end of the rod body, the fixing pin is located at the other end of the rod body, the spring is sleeved on the rod body and connected with the head, the fixing pin is approximately perpendicular to the locking pin, the well lid and the diameter enlarging portion are formed with a countersunk hole, the countersunk hole has a quincunx hole, when the well lid covers the opening, the quincunx holes are aligned with each other, so that the fixing pin can be restrained after passing through the quincunx hole, and the spring is pressed between the head and the well lid.

Preferably, the head of the locking pin has a counter bore having a shape corresponding to a shape of the engagement portion of the special tool.

Preferably, the counter bore of the head of the locking pin has a triangular shape, a rectangular shape, or a diamond shape.

Preferably, a grip portion for gripping to rotate the lifting ring is provided on the lifting ring.

Preferably, the internal and external threads are trapezoidal threads.

The invention has the advantages that the height of the well lid and the inclination angle of the well lid can be quickly adjusted no matter the well lid is newly installed or the original well lid is reinstalled, so as to optimally fit the road surface to be applied, and after the well lid is covered, the noise generated when the well lid is rolled is reduced by quickly locking the well lid.

Drawings

The foregoing and other aspects of the present invention will be more fully understood from the following detailed description, taken together with the following drawings. It is noted that the drawings may not be to scale for clarity of illustration and that this does not detract from the understanding of the invention. In the drawings:

FIG. 1 schematically illustrates an assembled cross-sectional view of a well lid assembly according to one embodiment of the invention;

figure 2a schematically shows a cross-sectional view of the base of the well lid assembly according to figure 1, taken along section line a-a;

figure 2b schematically shows a top view of the base of the well lid assembly according to figure 1;

fig. 3a schematically shows a cross-sectional view of the base rail according to fig. 1;

fig. 3b schematically shows a top view of the base rail according to fig. 1;

figure 4a schematically shows a cross-sectional view of the lifting ring of the manhole cover assembly according to figure 1;

figure 4b schematically shows a top view of the lifting ring of the manhole cover assembly according to figure 1;

figure 5a schematically illustrates a bottom view of the well lid assembly according to figure 1;

figure 5b schematically shows a cross-sectional view of the well lid according to figure 4;

figure 5c schematically shows a top view of the well lid according to figure 4;

FIG. 6a schematically illustrates an enlarged cross-sectional view of a locking device incorporated into the well lid assembly; and is

Fig. 6b schematically shows a top view of the anti-theft lock hole of the locking device shown in fig. 6 a.

Detailed Description

In the various figures of the present application, features that are structurally identical or functionally similar are denoted by the same reference numerals.

FIG. 1 schematically illustrates a well lid assembly according to one embodiment of the invention. As shown, the manhole cover assembly mainly includes a base 10, a base rail 20, a lifting ring 30, and a manhole cover 40. The base 10, base track 20, lift ring 30 and well cover 40 of the well cover assembly may be made of, for example, a ductile iron material. Preferably, in order to quickly lock the well lid, the well lid assembly further comprises a locking device 50.

As shown in fig. 2a and 2b, the base 10 includes a generally cylindrical body 11 and a flange 12 extending radially outward from one end of the body 11. In order to reduce the weight of the base 10, a plurality of lightening holes 17 are circumferentially distributed in the flange 12 of the base 10. In addition, two threaded holes 13 are also diametrically symmetrically provided in the flange 12 of the base 10, and these threaded holes 13 are inserted with adjustment bolts 2 (fig. 1) to adjust the inclination angle of the base 10 with respect to the base rail 20. Two recesses 18 are diametrically symmetrically provided on the lower surface of the flange 12 at 90 degrees from the threaded hole 13, and two adjustment cylinders 3 (see fig. 1) are respectively accommodated in the two recesses 18.

The main body 11 and the flange 12 are also integrally formed with a plurality of reinforcing ribs 15 for reinforcing the strength of the base 10 itself. The reinforcement ribs 15 are distributed around the flange 12, for example one reinforcement rib 15 may be located between two lightening holes 17. At least one turn of internal threads 14 for engaging external threads of a later-described lift ring 30 is formed on an inner circumferential surface of the body 11 of the base 10.

On the upper surface of the internal thread 14, three support blocks 16 are provided at intervals of 120 degrees, respectively, and the support blocks 16 preferably protrude upward from the upper surface of the internal thread by 1mm and have a length of 50mm in the circumferential direction for stably supporting the lift ring 30 to reduce the wear of the thread.

Of course, the number of the supporting blocks 16 is not limited to 3, and may be 3 or more.

As shown in fig. 3a and 3b, the base rail 20 includes a ring-shaped main body 21 and three fixing portions 22 extending radially outward from an outer circumferential surface of the main body 21 at regular intervals, the fixing portions 22 having an L-shape in a cross section passing through a central axis of the main body 21, including a horizontal portion 221 extending radially outward in a planar direction of the main body 21 and a vertical portion 222 extending upward from a distal end of the horizontal portion 221 perpendicular to the plane of the main body 21, and having a screw hole extending radially in the planar direction of the main body 21 near an upper end of the vertical portion 222 for insertion of a fixing bolt 24, an axis of the screw hole being parallel to a plane of the main body 12, the fixing bolt 24 being adjustable to interact with the flange 12 of the base 10, thereby rotatably associating the base 10 and the base rail 20 with each other, and preventing the base 10 from being detached from the base rail 20.

The part of the body 21 of the base rail 20 facing the flange 12 of the base has an annular recess 23, the adjusting cylinder 3 is accommodated both in the groove 18 of the flange of the base and in the recess 23, and the length of the adjusting cylinder is set to be smaller than the width of the annular recess 23, so that the adjusting cylinder 3 is rotated in the recess 23 about the center of the base rail 20, whereby the base 10 is rotatable relative to the base rail 20. As shown in fig. 1, in a state where the base 10 is coupled to the base rail 20, the fixing bolt 24 is positioned above the flange 12 of the base, and restricts the base 10 from moving upward as shown in fig. 1. The adjusting bolts 2 pass through the threaded holes 13 on the flange 12 of the base 10 and abut against the concave parts 23 of the base rails 20, and the inclination angle of the base 10 relative to the base rails 20 can be adjusted by advancing or retreating the two adjusting bolts 2, so that the base 10 can concentrically rotate relative to the base rails 20 by adjusting the positioning of the cylinders 3 in the grooves 18 of the flange 12 of the base and the rotation in the concave parts 23 in the main body 21 of the base rails 20 to adapt to different ground unevenness or different ground inclination directions.

As shown in fig. 4a and 4b, the lift ring 30 also includes a generally cylindrical body 31. The diameter of the body 31 is smaller than that of the body 11 of the base 10 so that the body 31 of the lift ring 30 can be fitted into the base 10. An enlarged diameter portion 32 is formed at one end of the body 31 of the lift ring 30, and the enlarged diameter portion 32 is annular and extends axially and radially outward. Three counter bores 33 are formed in the bottom wall of the enlarged diameter portion 32 at regular intervals, but the number of the counter bores 33 is not limited to 3, and may be 3 or more.

Three or four or more external threads 35 are formed on the outer surface of the body 31 of the lift ring 30. The external thread 35 can be screwed onto the internal thread 14 of the base 10 when the lifting ring 30 is installed into the base 10. The internal thread 14 and the external thread 35 are both trapezoidal threads with a small thread taper angle, ensuring that the lifting ring 30 does not fall due to gravity when seated via its external thread 35 on the internal thread 14 of the base 10. After the lift ring 30 is seated in the base 10, the lift ring 30 may be raised or lowered in the axial/longitudinal direction with respect to the base 10 due to the interaction between the threads by manually rotating the lift ring 30 in forward and reverse directions. To facilitate the lifting operation, a grip is optionally formed on the inner wall of the body 31 of the lift ring 30 and/or in the inner and/or outer side wall of the enlarged diameter portion 32 for gripping for rotation.

As described above, the supporting block 16 is disposed on the upper surface of the internal thread 14 of the base 10, and the external thread 35 is supported on the supporting block 16, so as to relieve the stress applied to the internal thread 14 by the lifting ring 30, thereby protecting the external thread 35 and the internal thread 14 and improving the service life of the manhole cover assembly.

When the lifting ring 30 is installed in the base 10, the enlarged diameter portion 32 of the lifting ring 30 is flush with or exceeds the outer surface of the body 11 of the base 10 in the radial direction, which ensures that sufficient installation space is left for the region of the counter bore 33 when the road pavement material is filled therearound. Alternatively, in order to block the pavement material filled therearound, a blocking piece may be provided outside the counter bored hole 33 of the enlarged diameter portion 32. The shielding piece extends downward from the bottom wall of the enlarged diameter portion 32 shown in fig. 3, and is located radially outward of the counterbore 33. Meanwhile, the shielding piece can be configured to not contact with the main body 11 of the base 10 after the lifting ring 30 is assembled, so as not to affect the height adjustment of the lifting ring 30.

Three lugs 34 are arranged on the outer circumferential surface of the diameter-enlarged part 32 at positions close to the counter bores 33, the positions of the lugs are not limited to be close to the counter bores, and the lugs can be uniformly arranged at other positions, so that when the lifting ring is arranged on a road surface, acting forces acting on the external threads 35 and the internal threads 14 are reduced through the action of the lugs 34 and road surface paving materials, and the service life of the well cover is prolonged.

As shown in fig. 5a to 5c, the well cover 40 includes a main body 41 having a substantially circular disk shape. A pattern 45 is formed on the surface of the body 41 that faces upward after installation. A ring of flanges 42 axially extends from the mounted downward surface of the body 41, and reinforcing ribs 44 are formed inside the ring of flanges 42 for improving the strength of the well cover 40 itself.

The outer diameter of the ring flange 42 is smaller than the inner diameter of the body 31 of the lifting ring 30, and the outer diameter of the body 41 of the well cover 40 is larger than the inner diameter of the body 31 of the lifting ring 30, so that when the well cover 40 is installed in the lifting ring 30, the ring flange 42 extends into the lifting ring 30 to play a certain guiding and positioning role. As shown, when the well cover 40 is in place on the lifting ring 30, the lower surface 41a of the body 41 of the well cover 40 contacts the upper surface of the bottom wall of the enlarged diameter portion 32, and the upper surface of the well cover 40 is flush with the upper surface of the enlarged diameter portion 32 of the lifting ring 30.

At least 3 counter bores 43 are evenly arranged circumferentially in the body 41 of the well lid 40, radially outside the flange 42, and a part of the counter bores are shown as quincunx bores. The hole is, for example, in the shape of a cross, and one of the lines in the cross is shorter than the other line.

The counter bored hole 43 of the well cover 40 corresponds to the counter bored hole 33 of the lifting ring 30. That is, when the manhole cover 40 is mounted on the lifting ring 30, the counter bores 43 of the manhole cover 40 are aligned with the counter bores 33 of the lifting ring 30 to form locking holes for the locking devices 50 to be inserted into, thereby preventing the manhole cover from rotating when subjected to a horizontal external force. The locking device 50 shown in fig. 1 can be installed after the counter bores 43 of the well cover 40 and the counter bores 33 of the lifting ring 30 are aligned. For this reason, a portion of the counter bore 33 of the lifting ring 30, which directly contacts the counter bore 43 of the manhole cover 40 as a quincunx hole, is also shaped as a quincunx hole having the same shape.

Fig. 6a and 6b schematically show an embodiment of the locking device 50. The locking device 50 includes a locking pin having a body 51 and a head 52. The rod body 51 can pass through the counter sink hole 43 of the manhole cover and the counter sink hole 33 of the lifting ring which are plum blossom holes. The head 52 is connected to the proximal end of the shaft 51 and at the distal end of the shaft 51 there is provided a resilient pin 55, also referred to as a fixing pin, which is longitudinally arranged perpendicular to the longitudinal direction of the shaft 51. The length of the elastic pin 55 is set to be smaller than the longer linear portion of the cross-shaped spline hole but larger than the shorter linear portion of the cross-shaped spline hole. That is, when the length direction of the elastic pin is aligned with the longer linear portion of the cross-shaped spline hole, it can pass through the spline hole, and when the length direction of the elastic pin is not aligned with the longer linear portion of the cross-shaped spline hole or aligned with the shorter linear portion of the cross-shaped spline hole, it cannot pass through the spline hole and is restrained.

In the illustrated embodiment, the spring pin 55 is hollow in shape. It will be clear to the person skilled in the art that the spring pin may also take other forms, for example a solid shape. The elastic pin may be inserted into the rod body 51, or may be integrally formed on the outer surface of the rod body 51.

A spring 53 is also provided around the rod 51. After the well lid 40 is put in place on the bottom wall of the enlarged diameter portion 32 of the lift ring 30, the rod body 51 with the elastic pin 55 is inserted into the aligned quincunx hole, the spring 53 cannot pass through the quincunx hole and the spring 53 is pressed in the counter bore 43 of the well lid 40, one end abuts against the head 52 and the other end abuts against the end face adjacent to the counter bore 43. The elastic pin 55 is rotated in the direction after being inserted into the quincunx hole, so that the locking device 50 is restrained between the manhole cover and the lifting ring. Thus, the locking device 50 can prevent the manhole cover 40 from jumping up and down when vertical external force is applied, and reduce noise.

A sleeve 54 may be provided around the outer circumference of the spring 53 to guide the sliding movement of the spring 53. In addition, in the center of the head 52, there is provided a theft-proof lock hole 56 whose shape corresponds to that of a special tool, preferably triangular, so that only a tool having a triangular joint can operate the head 52.

The construction installation method of the manhole cover assembly according to the present invention is described as follows.

When the manhole cover assembly is installed, first, the base 10 is coupled to the base rail 20 with the adjustment cylinder 3 being placed in the groove 18 of the base and the recess 23 of the base rail 20, and the movement of the base 10 is blocked by the screwing of the fixing bolt 24 so that the base 10 cannot be detached from the base rail 20, and then the adjustment bolt 2 is screwed into the screw hole 13 of the flange 12 of the base against the recess 23. Then, the lifting ring 30 is screwed into the internal thread 14 of the base 10 in the rotating direction of the external thread 35, and then the base 10, the base rail 20, and the lifting ring 30 combined together are placed in the wellhead so that the base rail 20 contacts the cement base 1 and is fixed relative to the cement base. Initially, the lift ring 30 may be screwed into the base 10 at its lowest position so that the upper surface of the lift ring 30 is near ground level. Then, the upper surface of the lifting ring is substantially leveled with the ground level by finely adjusting the adjusting bolts 2 and simultaneously rotating the base 10 relative to the base rails 20. The movable range between the lift ring 30 and the base 10, i.e., the distance that can be moved upward from the contact between the lower surface of the bottom wall of the enlarged diameter portion 32 and the upper surface of the base 10, is set as desired. By adopting the well lid assembly with the design, even if the ground is sunk in the future or the pavement is heightened as required, the height and the gradient of the lifting ring can be continuously adjusted only by loosening the road material on the ground around the lifting ring, so that the well mouth meets the requirement of the pavement.

After the height and inclination of the lifting ring 30 are adjusted, the periphery is reinforced by road paving materials, and then the lifting ring 30 can be covered with the well cover 40.

When the manhole cover 40 is covered, the manhole cover 40 is put into the enlarged diameter portion 32 of the lifting ring 30. Then, the locking pin with the spring 53 is inserted into the locking hole in a direction, that is, the elastic pin 55 is aligned with the longer straight portion of the cross-shaped quincunx hole, and is rotated in a direction of, for example, 90 degrees, so that the elastic pin 55 enters the lower end countersunk groove of the countersunk hole 33 of the lifting ring 30, and thus the spring 53 always exerts an axial retaining force between the head 52 of the locking pin and the well cover 40, and the well cover 40 can be prevented from jumping during use, and noise can be reduced.

When the manhole cover 40 needs to be lifted, the head 52 of the locking pin is pressed downwards and then rotated by 90 degrees, so that the elastic pin 55 is aligned with the longer straight line part of the cross-shaped quincunx hole, and the locking pin is jacked up under the elastic force of the spring 53 and taken out. Then the hook hooks into the exhaust hole of the well lid, and the well lid can be taken down. The manhole cover can be removed in this way before the height and inclination of the lifting ring are adjusted for future ground subsidence or for elevated road surfaces as mentioned above. When the well cover 40 is covered, the method is repeated.

While embodiments of the invention have been described above, it will be understood by those skilled in the art that the present invention is not limited to these specifically described matters.

It should be clear that the quincunx hole used in the present invention is not limited to the cross shape, and any shape that can restrict the rotation of the elastic pin by a certain angle after inserting it in the direction can be used for the quincunx hole.

By adopting the technical scheme of the invention, the well cover can be lifted and inclined relative to the road surface as required, different requirements for road surface laying are met, and even if the road surface sinks after many years of road surface laying or needs to be integrally paved again, the requirements of the road surface can be met only by adjusting the lifting ring to a new height and inclination, so that the maintenance in the future is facilitated and the construction cost is correspondingly reduced. In addition, the locking device can quickly and reliably lock the well cover, reduces the possibility of noise during use, and improves the road paving quality.

Although specific embodiments of the invention have been described herein in detail, they have been presented for purposes of illustration only and are not to be construed as limiting the scope of the invention. Various substitutions, alterations, and modifications may be devised without departing from the spirit and scope of the present invention.

Claims

1. A well lid assembly, comprising:

the base is provided with a cylindrical main body and a flange extending outwards from one end of the main body in the radial direction, at least one circle of internal threads are formed on the inner wall of the main body, and an adjusting device is arranged on the flange;

the lifting ring is provided with a cylindrical main body and an enlarged diameter part positioned at one end of the main body, at least three circles of external threads are formed on the outer wall of the main body of the lifting ring, and the enlarged diameter part forms an opening of the lifting ring; and

a well lid for covering the opening,

the body of the lift ring is mounted within the body of the base such that the external threads of the lift ring are threadably engaged with the internal threads of the base to selectively move the lift ring relative to the base along the longitudinal axis by rotation,

wherein the manhole cover assembly further comprises a base track for engaging the cement base, the base track having a circular body and the base being mounted relative to the base track such that the angle of inclination of the base relative to the base track is adjustable by the adjustment means on the flange of the base,

wherein, a pair of threaded holes which are opposite in diameter are arranged on the flange of the base and are used for a pair of adjusting bolts to be screwed and penetrated in the axial direction, when the base is arranged on the base track, the adjusting bolts can extend out of the threaded holes and abut against the upper surface of the base track through screwing,

wherein the main body of the base rail includes an annular recess on an upper surface in a circumferential direction, against which the adjusting bolt is abutted and accommodated when the base is mounted to the base rail, and

wherein a pair of diametrically opposed radially extending grooves are provided on a lower surface of the flange of the base, the grooves facing the annular groove when the base is mounted on the base rail, and two adjustment cylinders are each received in the grooves and the annular groove, respectively, so that the base is rotatable relative to the base rail.

2. The well lid assembly of claim 1, wherein the internal threads of the base have at least three support blocks formed on an upper surface thereof, the support blocks being evenly spaced circumferentially.

3. The well cover assembly of claim 2, wherein the support block has a height of 1mm and a length in a circumferential direction of 50 mm.

4. The well lid assembly of any one of claims 1-3, wherein at least three projections are provided on an outer circumferential surface of the enlarged diameter portion of the lifting ring, the projections being evenly spaced in a circumferential direction, the projections being in contact with pavement material to relieve loads acting on the internal threads of the base and the external threads of the lifting ring when the well lid assembly is installed on a pavement.

5. The well lid assembly of any one of claims 1-3, wherein the base track includes at least three securing portions extending radially outward from a main body of the base track and evenly spaced apart, the securing portions having securing bolts disposed thereon, the securing bolts having an axial direction parallel to a direction of a plane of the base track, the securing bolts being capable of extending inward beyond an outer circumference of a flange of the base by screwing when the base is installed on the base track to prevent the base from being disengaged from the base track.

6. The well lid assembly of any one of claims 1-3, further comprising a locking device for removably locking the lifting ring and the well lid together.

7. The well lid assembly of claim 6, wherein the locking device comprises a locking pin, a fixing pin and a spring, the locking pin comprises a rod body and a head part at one end of the rod body, the fixing pin is at the other end of the rod body, the spring is sleeved on the rod body and connected with the head part, the fixing pin is perpendicular to the locking pin, the well lid and the diameter enlarging part are formed with counter bores, the counter bores have quincunx holes, when the well lid covers the opening, the quincunx holes are aligned with each other, so that the fixing pin can be restrained after passing through the quincunx holes, and the spring is compressed between the head part and the well lid.

8. The well lid assembly of claim 7, wherein the head of the locking pin has a counter bore having a shape corresponding to a shape of the engagement portion of the special tool.

9. The well lid assembly of claim 8, wherein the counter bore of the head of the locking pin has a triangular shape, a rectangular shape, or a diamond shape.

10. The well lid assembly of any one of claims 1-3, wherein a grip is provided on the lifting ring for gripping to rotate the lifting ring.

11. The well lid assembly of any one of claims 1-3, wherein the internal and external threads are trapezoidal threads.