Bow thruster tunnel grating with telescopic rod

Abstract

The application provides a bow side thrust tunnel grating with telescopic rods, which comprises a telescopic rod base connected with the inner wall of the bow side thrust tunnel, the telescopic rod base is internally provided with telescopic rods which can be accommodated in the telescopic rod base, and the movable ends of the plurality of telescopic rods are extended to form a mesh grating in the bow side thrust tunnel. The telescopic rod base can be in various forms, and the telescopic direction of the telescopic rods can be linear or curved. The rod body of the telescopic rod can be provided with a through hole to facilitate the penetration of other telescopic rods when a plurality of telescopic rods are crossed. In addition, a clamping structure can also be arranged at the movable end of the telescopic rod to facilitate the mutual clamping of the ends of a plurality of telescopic rods when the ends are connected, so as to improve the stability and prevent displacement. The application can flexibly change the grating form and the grating bar density by controlling the telescopic rods, so as to adjust the influence of the grating on the nearby flow field and the pollution blocking capacity. In addition, the freely changed grating is convenient for personnel, equipment and the like to enter the bow side thrust tunnel, and is beneficial to the operation, maintenance and the like in the bow side thrust tunnel.

Description

Technical Field

[0001] This invention relates to the field of shipbuilding technology, and in particular to a bow thrust tunnel grid with telescopic rods. Background Technology

[0002] Different ship configurations have different requirements for bow thrusters. When a ship is traveling at high speed, the propeller in the bow thruster tunnel often stops working. Because the bow thruster tunnel affects the hull line and alters the flow field, it often increases hull drag. In this case, it is necessary to minimize the impact of the bow thruster tunnel. When a ship is traveling at low speed or stationary, impurities, microorganisms, etc., often enter the bow thruster tunnel and accumulate, adhere, and corrode, affecting the normal operation of the bow thruster. In this case, a denser bow thruster grid is needed to block debris from entering. When the bow thruster needs maintenance, the tunnel opening needs to be enlarged to facilitate the entry of personnel and equipment. In this case, the obstruction area of ​​the grid at the tunnel opening needs to be reduced. However, existing bow thruster grids are often fixed at the bow thruster tunnel opening and cannot be adjusted according to the ship's condition. Summary of the Invention

[0003] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a retractable bow thrust tunnel grid. The grid is located near the entrance of the bow thrust tunnel and is equipped with a remotely controllable telescopic rod. The grid bars can be flexibly extended or retracted according to people's needs to change the grid form and the density of the grid bars. This is beneficial for ships to adjust the flow field when sailing at high speed, effectively intercept pollution when sailing at low speed, and facilitate passage during maintenance, thereby effectively ensuring the speed and cleanliness of ships.

[0004] To achieve the above and other related objectives, the present invention provides a bow-side thrust tunnel grid with telescopic rods, including a telescopic rod base connected to the inner wall of the bow-side thrust tunnel. The telescopic rod base contains telescopic rods that can be housed therein. The fixed end of the telescopic rod is connected to the telescopic rod base, and the movable end can extend out from the telescopic rod base. After the movable ends of multiple telescopic rods extend out, a mesh grid is formed inside the bow-side thrust tunnel.

[0005] The port of the telescopic pole base for the extension of the telescopic pole is covered with a covering layer. When the telescopic pole passes through, the covering layer is punctured to facilitate the insertion of the pole. When the telescopic pole does not pass through, the covering layer completely covers the outlet of the telescopic pole base to prevent blockage and corrosion by debris.

[0006] Optionally, the covering layer is a flexible material layer, and the central area of ​​the flexible material layer has multiple intersecting cuts, thereby dividing the flexible material layer into multiple petals. When the telescopic rod extends, the petals are opened; after the rod is retracted to the base of the telescopic rod, the petals rebound and close under the elastic action of the material.

[0007] Optionally, multiple telescopic rod bases are arranged circumferentially along the bow-side thrust tunnel and located on the same grid plane. The grid plane is a single layer or two or more layers. The grid plane intersects perpendicularly or obliquely with the axial direction of the bow-side thrust tunnel. The telescopic rod bases stand upright or obliquely on the inner wall of the bow-side thrust tunnel.

[0008] Optionally, the telescopic pole can be folded, and the telescopic direction can be straight or curved; the telescopic pole has multiple segments, each with a different diameter, the smaller diameter telescopic pole segment can be retracted into the larger diameter telescopic pole segment, and the largest diameter telescopic pole segment is placed in the telescopic pole base and connected to the telescopic pole base.

[0009] Optionally, the telescopic pole has through holes in its body to allow other telescopic poles to pass through when multiple telescopic poles intersect.

[0010] Optionally, the movable end of the telescopic rod is provided with an interlocking structure to facilitate the interlocking of the ends of multiple telescopic rods when they are connected.

[0011] Optionally, the inner wall of the bow-side thrust tunnel is provided with a support leg and an outer contour structure near the axis. The support leg connects the inner wall of the bow-side thrust tunnel and the outer contour structure. The telescopic rod base is fixed to the inner side of the outer contour structure to realize the connection between the telescopic rod base and the inner wall of the bow-side thrust tunnel. The telescopic rod base is provided on the inner side of the outer contour structure.

[0012] Optionally, a slot is provided on the inner wall of the thrust tunnel or on the inner side of the outer contour structure. When the telescopic rod crosses the outer contour structure in a straight line, the slot is used to accommodate the movable end of the telescopic rod. A telescopic rod fixing device is provided in the slot to place and fix the movable end of the telescopic rod. A covering layer is also provided at the opening of the slot.

[0013] Optionally, the outer contour structure is a ring, the telescopic rod base is cylindrical, and multiple telescopic rod bases are symmetrically placed diagonally above the inner side of the outer contour ring. A telescopic rod is arranged in a single telescopic rod base. The telescopic rod is straight and extends across the outer contour structure in a straight line. The telescopic rods extending from the left and right sides intersect.

[0014] Optionally, the outer contour structure is a ring, the telescopic rod base is multi-branched, the telescopic rod base has multiple branches facing up and down, each branch is equipped with a telescopic rod, the two telescopic rod bases are symmetrically placed on the left and right sides inside the ring, the telescopic rod is arc-shaped, and after the telescopic rods on the left and right sides extend, their movable ends interlock with each other to form a closed ring.

[0015] As described above, the present invention provides a bow-side thrust tunnel grid with telescopic rods, comprising a telescopic rod base connected to the inner wall of the bow-side thrust tunnel, wherein telescopic rods are housed within the telescopic rod base, the fixed end of the telescopic rod is connected to the telescopic rod base, and the movable end extends out from the telescopic rod base. After the movable ends of multiple telescopic rods extend out, a mesh grid is formed inside the bow-side thrust tunnel. The telescopic rod base can be of various forms, and a single telescopic rod base can accommodate multiple telescopic rods. The telescopic direction of the telescopic rods can be straight or curved. The telescopic rod body can be provided with through holes to allow multiple telescopic rods to pass through each other when they intersect. In addition, an interlocking structure can be provided at the movable end of the telescopic rod to facilitate interlocking when the ends of multiple telescopic rods are connected, thereby improving stability and preventing slippage or displacement. This invention can flexibly change the form and density of the grid by controlling the extension and retraction of the telescopic rod, so as to adjust the influence of the grid on the nearby flow field and its pollution interception capacity. In addition, the freely changeable grid also facilitates the entry of personnel and equipment into the bow thrust tunnel, which is beneficial to the operation, inspection and maintenance inside the bow thrust tunnel. Attached Figure Description

[0016] Figure 1 The diagram shows a structural schematic of a bow-thrust tunnel.

[0017] Figure 2a The diagram shows the telescopic rod base protruding relative to the inner wall of the thrust tunnel in this invention.

[0018] Figure 2b The diagram shows the telescopic rod base being recessed relative to the inner wall of the thrust tunnel in this invention.

[0019] Figure 3 The diagram shows the extension action of the telescopic rod in this invention.

[0020] Figure 4 The diagram shown is a schematic representation of the structure of the covering layer in this invention.

[0021] Figure 5a The diagram shown is a structural schematic of the multi-layer grid plane in this invention.

[0022] Figure 5b The diagram shows a structural schematic of the present invention in which the plane of the grid is obliquely intersected with the axis of the thrust tunnel.

[0023] Figure 6a The diagram shows a schematic of the telescopic rod with a through hole in this invention.

[0024] Figure 6b The diagram shows a structural schematic of the telescopic rod with an interlocking structure on its movable end in this invention.

[0025] Figure 7 The diagram shows a grid structure formed by a straight telescopic rod in this invention.

[0026] Figure 8 The diagram shows a grid structure formed by the arc-shaped telescopic rod in this invention.

[0027] Component designation explanation

[0028] Bow-side thrust tunnel 21, bow 12, telescopic rod base 24, telescopic rod 23, telescopic direction 22, motor 32, motor rotation shaft 35, first connecting rod 37, second connecting rod 38, direction of movement 33, hinge 39, covering layer 41, petals 42, grid plane 51, through hole 62, interlocking structure 64, support leg 75, outer contour structure 710, slot 77, axis of symmetry 78. Detailed Implementation

[0029] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0030] In the detailed description of embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged and not to scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In actual fabrication, the three-dimensional spatial dimensions of length, width, and depth should be included.

[0031] For ease of description, spatial relation terms such as “below,” “under,” “lower than,” “below,” “above,” and “upper” may be used herein to describe the relationship between one element or feature shown in the accompanying drawings and other elements or features. It will be understood that these spatial relation terms are intended to include directions other than those depicted in the drawings for the device in use or operation. Furthermore, when a layer is referred to as being “between” two layers, it can be the only layer between the two layers, or there may be one or more layers in between. The phrase “between” as used herein includes both endpoint values.

[0032] In the context of this application, the structure described above the first feature may include embodiments in which the first and second features are formed in direct contact, or embodiments in which additional features are formed between the first and second features, such that the first and second features may not be in direct contact.

[0033] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0034] like Figure 2a , 2b As shown, this invention provides a bow thrust tunnel grid with telescopic rods, including a telescopic rod base 24. The telescopic rod base 24 is connected to the inner wall of the bow thrust tunnel 21. The telescopic rod base 24 houses telescopic rods 23, meaning the entire telescopic rod 23 can be completely housed within the telescopic rod base 24. The fixed end of the telescopic rod 23 is connected to the telescopic rod base 24, and the movable end can extend out from the telescopic rod base 24. After the movable ends of multiple telescopic rods extend out, they form a mesh grid inside the bow thrust tunnel 21. The telescopic rod base 24 protrudes or is recessed relative to the inner wall of the bow thrust tunnel 21.

[0035] Specifically, the telescopic pole base 24 has a certain accommodating space to house a telescopic pole 23 of a certain length and telescopic pole control equipment to control the extension and retraction of the telescopic pole 23. The telescopic pole base 24 can be cylindrical, polygonal, Y-shaped, branched, or a combination thereof, and a single telescopic pole base 24 can accommodate multiple telescopic poles 23. The control equipment within the telescopic pole base 24 includes, but is not limited to, rotatable linkage structures, gear systems, and transmission screws. Figure 3 The diagram shows a linkage structure. The wire passes through the hull and connects to the motor 32 inside the telescopic rod base 24. When the motor 32 starts, the motor rotation shaft 35 drives the first connecting rod 37 and the second connecting rod 38 to rotate, thereby causing the telescopic rod 23 to extend or retract.

[0036] Furthermore, such as Figure 4 As shown, the port of the telescopic pole base for the extension of the telescopic pole is covered with a flexible, corrosion-resistant, and wear-resistant covering layer 41 of a certain strength. When the telescopic pole 23 passes through, the covering layer 41 is punctured to facilitate the insertion of the pole; when the telescopic pole 23 does not pass through, the covering layer 41 completely covers the outlet of the telescopic pole base to prevent debris from clogging or corroding it. As an example, the covering layer 41 is a flexible material layer with multiple intersecting slits in the central area, thereby dividing the flexible material layer into multiple petals 42. When the telescopic pole 23 extends, the petals 42 are opened; after the pole is retracted to the telescopic pole base, the petals 42 spring back and close under the elastic action of the material. Figure 4 As shown, the telescopic pole base has a circular cross-section. When the telescopic pole is not in use, it is covered by a covering layer, and when it is in use, it is pierced by the telescopic pole body.

[0037] Furthermore, such as Figure 5a , 5b As shown, multiple telescopic rod bases 24 are arranged circumferentially along the bow thrust tunnel 21 and located on the same grid plane 51. The grid plane 51 can be single-layered or multi-layered (two or more layers). The grid plane 51 intersects perpendicularly or obliquely with the axial direction of the bow thrust tunnel 21. The telescopic rod bases 24 can stand upright or obliquely on the inner wall of the bow thrust tunnel 21. Figure 5a As shown, two telescopic rod bases arranged circumferentially and at the same position along the tunnel length are located on the same grid plane and combined into one set of single-layer bases. The double-layer bases (i.e., two sets of single-layer bases) inside the tunnel form two grid planes standing upright inside the bow-side thrust tunnel 21; as Figure 5b As shown, two telescopic rod bases that are deviated in the tunnel length direction form a grid plane that stands obliquely inside the bow-side thrust tunnel 21.

[0038] Furthermore, the telescopic rod 23 is foldable, and the extension direction 22 can be straight or curved. The rod shape can be round, polygonal, etc., and the surface can be smooth or rough. The foldable telescopic rod has multiple segments, each with a different diameter. The smaller diameter segments can retract into the larger diameter segments, while the outermost, largest diameter segment is placed inside the telescopic rod base and connected to it. When the control device inside the telescopic rod base drives the telescopic rod to extend, the telescopic rod extends segment by segment from the base, moves a certain distance along the extension direction, and then stops. When the control device drives the telescopic rod to retract, it retracts segment by segment in the opposite direction of extension back to the base.

[0039] Furthermore, the telescopic pole 23 can be provided with a through hole 62 to allow other telescopic poles to pass through when multiple telescopic poles intersect, such as... Figure 6a As shown. Additionally, an interlocking structure 64 can be provided at the movable end of the telescopic rod 23 to facilitate interlocking when the ends of multiple telescopic rods are connected, thereby improving stability and preventing slippage or displacement, such as... Figure 6b As shown.

[0040] Generally, the number, shape, and size of telescopic pole bases and telescopic poles have a certain correspondence. For example, x telescopic pole bases can accommodate y or z telescopic poles, where x, y, and z are all positive integers. Specifically, the length, number, shape, size, and location of the telescopic pole bases and telescopic poles are determined according to design and construction requirements, tunnel location and size, ship hull conditions, and external environment.

[0041] Furthermore, such as Figure 7 , Figure 8As shown, a support leg 75 and an outer contour structure 710 are added to the inner side of the bow-side thrust tunnel 21 near the axis. The support leg 75 connects the inner wall of the bow-side thrust tunnel 21 and the outer contour structure 710. The telescopic rod base 24 is fixed to the inner side of the outer contour structure 710 to achieve the connection between the telescopic rod base 24 and the inner wall of the bow-side thrust tunnel. The inner side of the outer contour structure 710 is provided with one or more telescopic rod bases 24 to reduce the number of telescopic rod bases on the tunnel wall. The outer contour structure can be a circular ring, an elliptical ring, a polygonal ring, etc., with a certain thickness. In addition to accommodating wires, telescopic rod control equipment, etc., it should also enhance the overall strength and stability of the grid.

[0042] Furthermore, a slot 77 is provided on the inner wall of the thrust tunnel 21 or on the inner side of the outer contour structure 710. When the telescopic rod crosses the outer contour structure 710 in a straight direction, the slot 77 is used to accommodate the movable end of the telescopic rod 23. A telescopic rod fixing device, such as a fixing clamp, is provided inside the slot 77 to place and fix the movable end of the telescopic rod, reducing swaying and increasing stability. Here, the slot acts as a substitute for the telescopic rod base, thereby reducing the number of telescopic rod bases. The shape of the slot includes, but is not limited to, circular, elliptical, polygonal, and irregular shapes, and its dimensions are determined by the shape and dimensions of the telescopic rod, construction, structural strength, etc. See also Figure 4 The opening of the tunnel is also provided with a flexible, corrosion-resistant, and wear-resistant covering layer 41 with a certain strength.

[0043] See Figure 7 One embodiment of the grille has eight legs 75, six telescopic rod bases 24, and an outer ring-shaped outer contour structure 710. The telescopic rod bases 24 are cylindrical and of a certain length. Multiple telescopic rod bases 24 are symmetrically positioned diagonally above the inner side of the outer ring. One telescopic rod 23 is arranged within each telescopic rod base 24. The telescopic rods 23 are straight, and the telescopic rods on the left and right sides intersect. A corresponding number of through holes 62 and slots 77 are provided at corresponding positions on the telescopic rod body and the ring. The dimensions of the channels and slots are larger than the dimensions of the rod body through which they pass.

[0044] When the telescopic rod in the base of the telescopic rod on side A or side B extends, the extended telescopic rod is inserted into the slot on the inner side of the ring, at which time the grid bars in the outer contour ring of the grid are parallel.

[0045] When both the telescopic rods on side A and side B need to be extended, extend the telescopic rod on side A or side B first. Once the telescopic rod on that side is inserted into the slot inside the ring, extend the telescopic rod on the other side. The telescopic rod on the other side is smaller; it passes through the through hole in the telescopic rod body of the previous side and is then inserted into the corresponding slot inside the ring. At this point, the grid bars inside the outer ring of the grille intersect horizontally and vertically.

[0046] The base of the telescopic pole and the outlet of the slot are provided with a flexible, corrosion-resistant, and wear-resistant covering layer 41 of a certain strength. See the description of the covering layer. Figure 4 .

[0047] See Figure 8 Another embodiment of the grille has 8 legs 75, 2 telescopic rod bases 24, and an outer contour structure 710 that is annular. The telescopic rod bases 24 are multi-layered branched, with multiple branches facing up and down. Each branch is equipped with a telescopic rod. The two telescopic rod bases 24 are symmetrically placed on the left and right sides inside the annulus. 8 telescopic rods 23 are arranged inside one telescopic rod base 24. The telescopic rods are arc-shaped. After the symmetrical telescopic rods on the left and right sides extend, their movable ends interlock with each other to form a closed annulus.

[0048] When the telescopic rod on side C or side D extends, the telescopic rod at the upper and lower ends of that side extends along the circular trajectory and stops extending at the position of axis of symmetry 78.

[0049] When the telescopic rods on sides C and D extend simultaneously, the telescopic rods on both sides come into close contact at the axis of symmetry. At this time, the grid bars inside the outer contour ring of the grille are multi-layered rings.

[0050] Both the C-side and D-side telescopic rods have interlocking structures 64 at their movable ends to enhance the connection between the two sides. For example... Figure 6b As shown, if the movable end faces of the telescopic rods on sides C and D are concave and convex structures, the telescopic rods on both sides can be tightly engaged when they are both located near the axis of symmetry.

[0051] In summary, this invention provides a bow-side thrust tunnel grid with telescopic rods, comprising a telescopic rod base connected to the inner wall of the bow-side thrust tunnel. The telescopic rod base houses telescopic rods, with fixed ends connected to the base and movable ends extending from it. Multiple telescopic rods, with their movable ends extending out, form a mesh grid within the bow-side thrust tunnel. The telescopic rod base can be of various forms, with a single base accommodating multiple telescopic rods. The telescopic rods can extend in either a straight line or a curve. Through holes can be provided in the rod body to allow multiple telescopic rods to pass through each other when they intersect. Furthermore, an interlocking structure can be provided at the movable end of the telescopic rod to facilitate interlocking when the ends of multiple telescopic rods are connected, thereby improving stability and preventing slippage or displacement. This invention can flexibly change the form and density of the grid by controlling the extension and retraction of the telescopic rod, so as to adjust the influence of the grid on the nearby flow field and its pollution interception capacity. In addition, the freely changeable grid also facilitates the entry of personnel and equipment into the bow thrust tunnel, which is beneficial to the operation, inspection and maintenance inside the bow thrust tunnel.

[0052] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A bow-side thrust tunnel grid with telescopic rods, characterized in that, It includes a telescopic rod base, which is connected to the inner wall of the bow-side thrust tunnel. The telescopic rod base has a built-in telescopic rod that can be housed therein. The fixed end of the telescopic rod is connected to the telescopic rod base, and the movable end can extend out from the telescopic rod base. After the movable ends of multiple telescopic rods extend out, they form a mesh grid inside the bow-side thrust tunnel. The port of the telescopic pole base for the extension of the telescopic pole is covered with a covering layer. When the telescopic pole passes through, the covering layer is punctured to facilitate the insertion of the pole. When the telescopic pole does not pass through, the covering layer completely covers the outlet of the telescopic pole base to prevent blockage and corrosion by debris.

2. The bow-side thrust tunnel grid with telescopic rod according to claim 1, characterized in that: The covering layer is a flexible material layer. The central area of ​​the flexible material layer has multiple intersecting cuts, which divide the flexible material layer into multiple petals. When the telescopic rod extends, the petals are opened; after the rod is retracted to the base of the telescopic rod, the petals rebound and close under the elastic action of the material.

3. The bow-side thrust tunnel grid with telescopic rod according to claim 1, characterized in that: Multiple telescopic rod bases are arranged circumferentially along the bow-side thrust tunnel and located on the same grid plane. The grid plane is a single layer or two or more layers. The grid plane intersects perpendicularly or obliquely with the axial direction of the bow-side thrust tunnel. The telescopic rod bases stand upright or obliquely on the inner wall of the bow-side thrust tunnel.

4. The bow-side thrust tunnel grid with telescopic rod according to claim 1, characterized in that: The telescopic pole can be folded, and its extension or retraction can be in a straight line or a curve. The telescopic pole has multiple segments, each with a different diameter. The smaller diameter telescopic pole segment can retract into the larger diameter telescopic pole segment, and the largest diameter telescopic pole segment is placed inside the telescopic pole base and connected to the telescopic pole base.

5. The bow-side thrust tunnel grid with telescopic rod according to claim 1, characterized in that: The telescopic pole has through holes so that when multiple telescopic poles intersect, other telescopic poles can be inserted into each other.

6. The bow-side thrust tunnel grid with telescopic rod according to claim 1, characterized in that: The movable end of the telescopic rod is equipped with an interlocking structure to facilitate the interlocking of the ends of multiple telescopic rods when they are connected.

7. The bow-side thrust tunnel grid with telescopic rod according to claim 1, characterized in that: The inner wall of the bow-side thrust tunnel is provided with a support foot and an outer contour structure near the axis. The support foot connects the inner wall of the bow-side thrust tunnel and the outer contour structure. The telescopic rod base is fixed to the inner side of the outer contour structure to realize the connection between the telescopic rod base and the inner wall of the bow-side thrust tunnel. The telescopic rod base is provided on the inner side of the outer contour structure.

8. The bow-side thrust tunnel grid with telescopic rod according to claim 7, characterized in that: A slot is also provided on the inner wall of the thrust tunnel or on the inner side of the outer contour structure. When the telescopic rod crosses the outer contour structure in a straight line, the slot is used to accommodate the movable end of the telescopic rod. A telescopic rod fixing device is provided in the slot to place and fix the movable end of the telescopic rod. A covering layer is also provided at the opening of the slot.

9. The bow-side thrust tunnel grid with telescopic rod according to claim 8, characterized in that: The outer contour structure is a ring, and the telescopic rod base is cylindrical. Multiple telescopic rod bases are symmetrically placed diagonally above the inner side of the outer contour ring. A telescopic rod is arranged inside a single telescopic rod base. The telescopic rod is straight and extends across the outer contour structure in a straight line. The telescopic rods extending from the left and right sides intersect.

10. The bow-side thrust tunnel grid with telescopic rod according to claim 8, characterized in that: The outer contour structure is a ring, and the telescopic rod base is multi-branched. The telescopic rod base has multiple branches facing up and down, and each branch is equipped with a telescopic rod. The two telescopic rod bases are symmetrically placed on the left and right sides inside the ring. The telescopic rod is arc-shaped. After the telescopic rods on the left and right sides extend, their movable ends interlock with each other to form a closed ring.

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