Hole opening protection device for hole digging pile
By replacing the concrete guardrail with steel guardrail cylinder, the problems of high construction cost and difficulty in controlling the hole hole protection device of holes is solved, and a more efficient and accurate construction process is achieved and the cost is reduced.
Patent Information
- Application Number
- CN202420797409.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-17
- Publication Date
- 2025-03-14
- Estimated Expiration
- 2034-04-17
AI Technical Summary
In the prior art, the use of concrete guard rings for hole-punch hole protection devices has problems such as high construction cost and difficult to control dimensional accuracy.
The steel guard cylinder is used to replace the traditional concrete guard cylinder. The steel guard cylinder can be recycled, avoiding the impact on the formwork and the vibration rod during concrete pouring, thereby improving construction efficiency and accuracy.
Through the use of steel guard cylinders, material waste is reduced, working efficiency is improved, deviations in pile positions and pile diameters are avoided, and construction costs are reduced.
Smart Images
Figure CN222614237U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of road engineering construction, and more specifically to a bored pile hole protection device. Background Art
[0002] The bored pile hole refers to the hole for the bridge pile dug manually on the ground when building a bridge during road construction. Due to the unstable ground soil, a hole guard ring needs to be installed at the bored pile hole to fix the pile position, guide the drilling direction, isolate surface water from flowing into the wellbore, and protect the hole from collapse.
[0003] At present, concrete retaining rings are usually used to protect the openings during road construction. The specific operation steps of using concrete retaining rings are: first, the prepared concrete retaining ring mold needs to be placed on the ground at the opening, then concrete is poured into the mold, and then the concrete retaining ring mold is taken out after a period of time, and finally the poured concrete retaining ring needs to be cured for a period of time.
[0004] However, the concrete retaining ring currently used has at least the following two shortcomings, in other words, which are the technical problems to be solved by the present utility model:
[0005] 1. High construction cost. It is necessary to make a concrete retaining ring template, pour the concrete retaining ring in the template after the template is set, and then maintain it after the template is removed, which increases the time cost; after the concrete retaining ring is poured, the pile foundation under the concrete retaining ring must be constructed, the concrete retaining ring must be removed, and the mold must be used again at the next bored pile hole to repeat the pouring and maintenance of the concrete retaining ring, which increases the time and money cost.
[0006] 2. It is difficult to control the dimensional accuracy. During the pouring of the concrete retaining ring, the impact of the pouring concrete on the formwork and the influence of the vibrating rod on the formwork can easily cause the formwork to deviate, resulting in deviations in the pile position and pile diameter.
[0007] In summary, a bored pile hole protection device is now urgently needed to address the deficiencies of the prior art. Utility Model Content
[0008] The utility model provides a bored pile hole mouth protection device, which replaces a traditional concrete guard ring with a steel guard ring cylinder, thereby: 1. The steel guard ring cylinder can be recycled and there is no need to repeatedly make new guard rings, which saves costs and improves work efficiency; 2. The steel guard ring does not have a casting process of a concrete guard ring, thus avoiding the impact force of pouring concrete on the template and the influence of a vibrating rod on the template, which causes the template to deviate and thus causes deviations in pile position and pile diameter.
[0009] The specific solutions adopted by the utility model to solve the above technical problems are as follows:
[0010] A bored pile hole protection device comprises: a guard ring cylinder, the guard ring cylinder comprises a first plate body, a second plate body, a third plate body, and a fourth plate body, the first plate body is arranged in parallel with the second plate body, and the first plate body is connected to the fourth plate body, and the fourth plate body is connected to the second plate body, the fourth plate body is an inner cylinder ring of the guard ring cylinder, the first plate body is connected to the third plate body, and the third plate body is connected to the second plate body, and the third plate body is an outer cylinder ring of the guard ring cylinder.
[0011] As a further preferred embodiment, the bored pile hole protection device also includes an anti-drop plate, the first plate body is connected to the top surface of the anti-drop plate, and a first through hole smaller than or equal to the inner diameter of the guard ring cylinder is provided in the anti-drop plate.
[0012] As a further preferred solution, an upward protrusion is provided on the top surface of the anti-drop plate, a groove matching the protrusion of the anti-drop plate is provided on the bottom of the first plate body, and the first plate body and the anti-drop plate are connected through the protrusion and the groove.
[0013] As a further preferred solution, a receiving groove for receiving the retaining ring cylinder is provided on the top surface of the anti-drop plate.
[0014] Further as a preferred embodiment, the bored pile hole protection device also includes an anti-drop plate, and the anti-drop plate is provided with a first through hole with the same size as the outer diameter of the guard ring cylinder, the guard ring cylinder is sleeved in the first through hole of the anti-drop plate, and the guard ring cylinder and the anti-drop plate are integrally formed.
[0015] As a further preferred solution, the bored pile hole protection device further includes a guard ring reinforcement auxiliary structure connected to the third plate body, and the guard ring reinforcement auxiliary structure includes:
[0016] The sleeve is connected with the third plate body;
[0017] A reinforcing rod is plugged into the sleeve, and the bottom end of the reinforcing rod penetrates the anti-drop plate and is inserted into the soil under the anti-drop plate.
[0018] As a further preferred solution, a tip is provided at the bottom of the reinforcing rod, and a second through hole is provided at the anti-drop plate, and the tip passes through the sleeve and the second through hole and is inserted into the soil under the anti-drop plate.
[0019] As a further preferred solution, a water blocking plate is provided extending downwardly from the first plate body.
[0020] As a further preferred solution, a pointed plug portion is provided at the bottom of the water blocking plate.
[0021] As a further preferred solution, a hanging auxiliary structure for assisting hanging is provided on the second plate body, and the hanging auxiliary structure is an annular body.
[0022] The main beneficial effects of the above technical solution are:
[0023] The steel retaining ring cylinder in the above technical solution can be recycled, which reduces material waste and improves work efficiency. At the same time, it avoids the deviation of the formwork caused by the impact force of pouring concrete on the formwork and the influence of the vibrating rod on the formwork, thereby avoiding the deviation of the pile position and pile diameter caused by the displacement of the formwork, preventing the retaining ring cylinder from falling, and ensuring the placement accuracy of the retaining ring cylinder.
[0024] Further or more detailed beneficial effects will be described in detail in conjunction with specific examples in the specific implementation manner. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] The utility model is further described below in conjunction with the accompanying drawings:
[0026] Figure 1 The structure of the utility model is schematically shown in the main cross-sectional view Figure 1 .
[0027] Figure 2 The structure of the utility model is schematically shown in the main cross-sectional view Figure 2 .
[0028] Figure 3 The structure of the utility model is schematically shown in the main cross-sectional view Figure 3 .
[0029] Figure 4 The structure of the utility model is schematically shown in the main cross-sectional view Figure 4 .
[0030] Figure 5 The structure of the utility model is schematically shown in the main cross-sectional view Figure 5 .
[0031] As shown in the figure: soil-1, pile body-2, bored pile wall-3, guard ring cylinder-4, first plate body-41, second plate body-42, third plate body-43, fourth plate body-44, anti-drop plate-45, guard ring reinforcement auxiliary structure-431, sleeve-4311, reinforcement rod-4312, hanging auxiliary structure-421. DETAILED DESCRIPTION
[0032] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solution in the specific implementation of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the implementation of the present invention.
[0033] Embodiment 1
[0034] A bored pile hole protection device, as shown in the attached Figure 1 To Attachment Figure 5 As shown, the bored pile hole protection device includes: a retaining ring cylinder 4, a first plate body 41, a second plate body 42, a third plate body 43, and a fourth plate body 44.
[0035] Specifically, the retaining ring cylinder 4 includes a first plate 41, a second plate 42, a third plate 43, and a fourth plate 44. The first plate 41 and the second plate 42 are of equal size. The first plate 41 and the second plate 42 are arranged in parallel, the first plate 41 and the fourth plate 44 are connected, and the fourth plate 44 is connected to the second plate 42, wherein the fourth plate 44 is the inner cylinder ring of the retaining ring cylinder 4, and the first plate 41 and the third plate 43 are connected, and the third plate 43 and the second plate 42 are connected, wherein the third plate 43 is the outer cylinder ring of the retaining ring cylinder 4. The first plate 41 is the lower plate of the retaining ring cylinder 4, and the second plate 42 is the upper plate of the retaining ring cylinder 4. Thus, the first plate 41, the second plate 42, the third plate 43 and the fourth plate 44 can form a retaining ring cylinder 4. When viewed from above, the inner cylinder formed by the fourth plate 44 and the outer cylinder formed by the third plate 43 form two concentric circles. The first plate 41, the second plate 42, the third plate 43 and the fourth plate 44 are all steel plates with a thickness of 1 cm. According to the actual needs of construction, when the soil is relatively hard during the actual construction process, the retaining ring cylinder 4 can be a solid body, that is, there can be no gap between the third plate 43 and the fourth plate 44; when the soil is not hard enough, the retaining ring cylinder 4 can also be a hollow body, that is, there is a gap between the third plate 43 and the fourth plate 44. At this time, the first plate 41 located below is wider. The advantage of the wider first plate 41 is that the contact area between the retaining ring cylinder 4 and the soil at the pile hole is increased, thereby preventing the retaining ring cylinder 4 from falling down due to gravity. By using the steel retaining ring cylinder 4 formed by the first plate body 41, the second plate body 42, the third plate body 43 and the fourth plate body 44 to replace the traditional concrete retaining ring, it is not necessary to repeatedly pour the concrete retaining ring with concrete, nor is it necessary to perform maintenance work on the concrete retaining ring after the concrete retaining ring is poured, which speeds up the construction progress, improves the construction efficiency and saves material costs and time costs. In addition, since there is no need to pour concrete, it is avoided that during the pouring of the concrete retaining ring, the impact force of the pouring concrete on the formwork and the influence of the vibrator on the formwork cause the formwork to deviate, thereby causing deviations in the pile position and pile diameter.
[0036] Furthermore, as attached Figure 2 As shown, the bored pile hole protection device also includes an anti-drop plate 45, the first plate body 41 is connected to the top surface of the anti-drop plate 45, and a first through hole less than or equal to the inner diameter of the retaining ring cylinder 4 is provided in the anti-drop plate 45.
[0037] On the basis of the above, since the retaining ring cylinder 4 has a certain weight, during the construction process, the retaining ring cylinder 4 will fall down when placed on the soil of the pile hole. In order to better prevent the retaining ring cylinder 4 from falling, the bored pile hole protection device also includes an anti-falling plate 45, which is arranged below the retaining ring cylinder 4. The anti-falling plate 45 needs to be larger than the diameter of the outer cylinder ring of the retaining ring cylinder 4, so that the anti-falling plate 45 can support the retaining ring cylinder 4. The first plate body 41 of the retaining ring cylinder 4 is connected to the top surface of the anti-falling plate 45. The first plate body 41 and the anti-falling plate 45 can be connected by welding or by detachable connection. In addition, in order to facilitate the construction personnel to construct the pile foundation at the bottom of the pile hole, a first through hole less than or equal to the inner diameter of the retaining ring cylinder 4 is also provided on the anti-falling plate 45, and the first through hole allows the construction personnel to enter the pile foundation. Therefore, when the construction personnel need to operate the pile foundation, the construction personnel can enter the pile foundation at the bottom of the pile hole through the first through hole. The anti-drop plate 45 is provided to prevent the retaining ring cylinder 4 from sliding down in the soil. Meanwhile, a first through hole is provided in the anti-drop plate 45 to facilitate construction workers to enter the pile foundation at the bottom of the pile hole to perform operations.
[0038] Furthermore, an upward protrusion is provided on the top surface of the anti-drop plate 45, and a groove matching the protrusion of the anti-drop plate 45 is provided on the bottom of the first plate body 41, and the first plate body 41 and the anti-drop plate 45 are connected through the protrusion and the groove.
[0039] Specifically, since welding is inconvenient, and if the anti-drop plate 45 is connected to the retaining ring cylinder 4 by welding, when the construction workers need to take out the bored pile hole mouth protection device after the construction is completed, they cannot take it out flexibly. In order to be able to flexibly dismantle the bored pile hole mouth protection device, the retaining ring cylinder 4 and the anti-drop plate 45 can be detachably connected. The detachable connection at this time also needs to meet the requirements of being convenient for construction personnel to connect the retaining ring cylinder 4 with the anti-drop plate 45 and be able to limit the retaining ring cylinder 4. Therefore, a protrusion is provided on the top surface of the anti-drop plate 45, and a groove is provided at the bottom of the first plate body 41 of the retaining ring cylinder 4. The retaining ring cylinder 4 is connected with the protrusion of the anti-drop plate 45 through the groove of the first plate body 41. In this way, the retaining ring cylinder 4 can be limited and connected conveniently, and the inconvenience caused by welding work can be solved. On the other hand, since the retaining ring cylinder 4 and the anti-drop plate 45 have a certain weight, connecting the two together will be heavier. If there is no crane on the construction site, it is inconvenient for construction personnel to place or remove the work. Through the detachable connection method, the two can be taken out separately, which also facilitates the construction work of the construction personnel.
[0040] Furthermore, as attached Figure 3As shown, the bored pile hole protection device also includes a guard ring reinforcement auxiliary structure 431 connected to the third plate body 43, and the guard ring reinforcement auxiliary structure 431 includes: a sleeve 4311, the sleeve 4311 is connected to the third plate body 43; a reinforcing rod 4312, the reinforcing rod 4312 is plugged into the sleeve 4311, and the bottom end of the reinforcing rod 4312 passes through the anti-drop plate 45 and is inserted into the soil under the anti-drop plate 45.
[0041] Specifically, in order to prevent the pile foundation hole from being displaced and to more precisely control the position of the bored pile hole protection device at the pile hole, a guard ring reinforcement auxiliary structure 431 is also provided, wherein the guard ring reinforcement auxiliary structure 431 includes a sleeve 4311, and the sleeve 4311 is connected to the third plate body 43 of the guard ring cylinder 4; the guard ring reinforcement auxiliary structure 431 also includes a reinforcing rod 4312, and the reinforcing rod 4312 is plugged into the sleeve 4311, and the bottom end of the reinforcing rod 4312 passes through the anti-drop plate 45 and is inserted into the soil under the anti-drop plate 45. In order to better achieve this effect, the guard ring reinforcement auxiliary structure 431 can be provided on all sides of the guard ring cylinder 4, and the guard ring reinforcement auxiliary structure 431 is used to fix the guard ring cylinder 4 to the four sides of the pile, thereby effectively reducing the deviation of the pile foundation hole and improving the accuracy of pile foundation construction.
[0042] Furthermore, as attached Figure 3 As shown, a tip is provided at the bottom of the reinforcing rod 4312 , and a second through hole is provided at the anti-drop plate 45 . The tip passes through the sleeve 4311 and the second through hole and is inserted into the soil under the anti-drop plate 45 .
[0043] Specifically, in order to better insert the reinforcing rod 4312 of the retaining ring reinforcing auxiliary structure 431 into the soil for positioning insertion, a tip is also provided at the bottom of the reinforcing rod 4312. When the retaining ring cylinder 4 and the anti-drop plate 45 are connected, it is hoisted into the soil at the hole of the bored pile, and then the tip of the reinforcing rod 4312 passes through the sleeve of the third plate body 43, and then the tip of the reinforcing rod 4312 passes through the second through hole of the anti-drop plate 45 and is inserted into the soil. The tip is provided at the bottom of the reinforcing rod 4312 to facilitate the insertion of the reinforcing rod 4312 into the soil. Among them, the reinforcing rod 4312 is a steel chisel.
[0044] Furthermore, as attached Figure 3 To Attachment Figure 5 As shown, a water blocking plate 411 is provided extending downward from the first plate body 41 .
[0045] Specifically, there is surface water on the soil surface. In order to prevent the surface water from entering the pile hole from the retaining ring cylinder, a water blocking plate 411 is provided extending downward from the first plate body 41 of the retaining ring cylinder 4. Figure 4 As shown, by providing the water blocking plate 411, surface water can be effectively prevented from entering the pile hole.
[0046] Furthermore, as attached Figure 3 As shown, a pointed plug portion is provided at the bottom of the water blocking plate 411 .
[0047] Specifically, in order to better insert the water blocking plate 411 into the soil, a pointed inserting portion is further provided at the bottom of the water blocking plate 411 .
[0048] Furthermore, as attached Figure 5 As shown, a hanging auxiliary structure 421 for auxiliary hanging is provided on the second plate body 42, and the hanging auxiliary structure 421 is an annular body.
[0049] Specifically, when a crane is used to place the bored pile hole protection device, a hanging auxiliary structure 421 may be provided on the second plate body 42 of the retaining ring cylinder 4, and the hanging auxiliary structure 421 assists the crane in the hanging operation. The hanging auxiliary structure 421 may be an annular body, and when the bored pile hole protection device needs to be placed in the pile hole, the hook of the crane is hooked on the annular body to hang the bored pile hole protection device.
[0050] Embodiment 2
[0051] On the basis of the first embodiment, the difference between this embodiment and the first embodiment lies in that: the anti-drop plate 45 and the guard ring cylinder 4 in the first embodiment are achieved by providing an upward protrusion on the top surface of the anti-drop plate 45, and the bottom of the first plate body 41 is provided with a groove matching the protrusion of the anti-drop plate 45, and the first plate body 41 and the anti-drop plate 45 are connected by the protrusion and the groove to achieve limiting. However, in this embodiment, a receiving groove for accommodating the guard ring cylinder 4 is provided on the top surface of the anti-drop plate 45, and the guard ring cylinder 4 can be placed in the receiving groove to achieve limiting.
[0052] Specifically, in order to facilitate the positioning of the retaining ring cylinder 4 on the anti-drop plate 45, a receiving groove is also provided on the anti-drop plate 45. The receiving groove is a circular groove, the inner diameter of which is less than or equal to the inner diameter of the retaining ring cylinder 4, and the outer diameter of which is greater than or equal to the outer diameter of the retaining ring cylinder 4, so as to facilitate the placement of the retaining ring cylinder 4. When it is necessary to protect the hole of the bored pile, the construction personnel put the anti-drop plate 45 into the hole of the bored pile, and then put the retaining ring cylinder 4 formed by the first plate body 41, the second plate body 42, the third plate body 43, and the fourth plate body 44 into the receiving groove of the anti-drop plate 45, so that the receiving groove can accommodate part of the retaining ring cylinder 4. By providing the receiving groove on the anti-drop plate 45, the positioning of the retaining ring cylinder 4 can be achieved. In order to better limit the retaining ring cylinder 4, the outer diameter of the receiving groove can be set to the outer diameter of the retaining ring cylinder. In addition, the provision of the annular groove can also prevent a certain amount of surface water from flowing into the bored pile hole.
[0053] Embodiment 3
[0054] On the basis of the first embodiment, the difference between the present embodiment and the first embodiment is that the retaining ring cylinder 4 and the anti-drop plate 45 in the first embodiment are separate, while the retaining ring cylinder 4 and the anti-drop plate 45 in the present embodiment are integrally formed. Figure 3 or attached Figure 5 As shown, the bored pile hole mouth protection device also includes an anti-drop plate 45, and a first through hole with the same outer diameter as the retaining ring cylinder 4 is provided on the anti-drop plate 45, the retaining ring cylinder 4 is sleeved in the first through hole of the anti-drop plate 45, and the retaining ring cylinder 4 and the anti-drop plate 45 are integrally formed.
[0055] Specifically, in order to prevent the retaining ring cylinder 4 placed at the bored pile hole from falling down, the bored pile hole protection device further includes an anti-falling plate 45, and the anti-falling plate 45 is provided with a first through hole with the same outer diameter as the retaining ring cylinder 4, the retaining ring cylinder 4 is sleeved in the first through hole of the anti-falling plate 45, and the retaining ring cylinder 4 is integrally formed with the anti-falling plate 45. In this way, the contact area between the bored pile hole protection device and the soil at the bored pile hole is increased, the effect of preventing the bored pile hole protection device from falling down can be achieved, and it is also convenient for construction personnel to enter the pile foundation from the first through hole to perform construction operations.
[0056] In summary, through the above embodiments, it is possible to reduce manpower input and improve labor efficiency in the process of protecting the bored pile holes of bridges, while reducing costs and ensuring construction accuracy to achieve the best protection effect.
[0057] The above are only preferred embodiments of the utility model, and do not limit the scope of the utility model. In addition, the terms "vertical", "lateral", "front", "rear", etc. mentioned in the embodiments of the utility model indicate the orientation or position relationship based on the orientation or position relationship shown in the drawings, or the orientation or position relationship in which the product is usually placed when in use, which is only for the convenience of describing the utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the utility model. It should be further explained that, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", "fix" and the like in the description should be understood in a broad sense, for example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, or the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the utility model can be understood according to the specific circumstances. The utility model will be described in detail with reference to the drawings and in combination with the embodiments.
[0058] Although the embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.
Claims
1. A bored pile hole protection device, characterized in that: include: A retaining ring cylinder (4), the retaining ring cylinder (4) comprising a first plate (41), a second plate (42), a third plate (43), and a fourth plate (44), the first plate (41) and the second plate (42) being arranged in parallel, the first plate (41) and the fourth plate (44) being connected, the fourth plate (44) and the second plate (42), the fourth plate (44) being the inner cylinder ring of the retaining ring cylinder (4), the first plate (41) and the third plate (43) being connected, the third plate (43) and the second plate (42), the third plate (43) being the outer cylinder ring of the retaining ring cylinder (4).
2. A bored pile hole protection device according to claim 1, characterized in that: The bored pile hole protection device further comprises an anti-drop plate (45), the first plate body (41) is connected to the top surface of the anti-drop plate (45), and the anti-drop plate (45) is provided with a first through hole whose diameter is less than or equal to the inner diameter of the retaining ring cylinder (4).
3. A bored pile hole protection device according to claim 2, characterized in that: An upward protrusion is provided on the top surface of the anti-drop plate (45), and a groove matching the protrusion of the anti-drop plate (45) is provided on the bottom of the first plate body (41), and the first plate body (41) and the anti-drop plate (45) are connected by the protrusion and the groove.
4. A bored pile hole protection device according to claim 2, characterized in that: A receiving groove for receiving the retaining ring cylinder (4) is provided on the top surface of the anti-drop plate (45).
5. A bored pile hole protection device according to claim 1, characterized in that: The bored pile hole mouth protection device further comprises an anti-drop plate (45), and the anti-drop plate (45) is provided with a first through hole having the same outer diameter as the retaining ring cylinder (4), the retaining ring cylinder (4) is sleeved in the first through hole of the anti-drop plate (45), and the retaining ring cylinder (4) and the anti-drop plate (45) are integrally formed.
6. A bored pile hole protection device according to any one of claims 2 to 5, characterized in that: The bored pile hole protection device further comprises a guard ring reinforcement auxiliary structure (431) connected to the third plate body (43), and the guard ring reinforcement auxiliary structure (431) comprises: A sleeve (4311), wherein the sleeve (4311) is connected to the third plate body (43); A reinforcing rod (4312), the reinforcing rod (4312) being plugged into the sleeve (4311), and the bottom end of the reinforcing rod (4312) passing through the anti-drop plate (45) and inserted into the soil under the anti-drop plate (45).
7. A bored pile hole protection device according to claim 6, characterized in that: A tip is provided at the bottom of the reinforcing rod (4312), and a second through hole is provided in the anti-drop plate (45); the tip passes through the sleeve (4311) and the second through hole and is inserted into the soil under the anti-drop plate (45).
8. A bored pile hole protection device according to claim 1, characterized in that: A water blocking plate (411) is provided extending downwardly from the first plate body (41).
9. A bored pile hole protection device according to claim 8, characterized in that: A pointed plug portion is provided at the bottom of the water blocking plate (411).
10. A bored pile hole protection device according to claim 1, characterized in that: The second plate body (42) is provided with a hanging auxiliary structure (421) for assisting hanging, and the hanging auxiliary structure (421) is an annular body.