An assembly device for a downhole tool

Abstract

This invention relates to an assembly apparatus for downhole tools, comprising a housing, a fixed plate disposed on the housing, and a telescopic assembly. An adjusting member is disposed within the housing. The telescopic assembly is configured to engage with the adjusting member, allowing the telescopic assembly to extend and retract radially via the adjusting member. This enables the telescopic assembly, after passing through an annular member to be assembled, to work with the fixed plate to limit the annular member's position. The housing is configured to extend into an extra-long, deep bore of the downhole tool, allowing the fixed plate and the telescopic assembly to assemble or detach the annular member at a target location within the extra-long, deep bore. This assembly apparatus enables precise assembly of the annular member to the target location within the extra-long, deep bore of the downhole tool, reducing assembly difficulty. Furthermore, the fixed plate can uniformly push the annular member during assembly, preventing damage to the annular member and ensuring assembly quality.

Description

Technical Field

[0001] This invention relates to the field of downhole tool manufacturing technology, and more specifically to an assembly device for downhole tools. Background Technology

[0002] Currently, in the manufacturing process of oil well tools, when assembling well tools with ultra-long deep holes (over 2 meters in length) and small diameters (less than 200 millimeters in diameter), it is necessary to precisely install annular components (such as positioning rings) in the housing with ultra-long deep holes. Furthermore, the axial distance of the annular components must meet the design requirements, and the annular components must be aligned with the positioning holes on the housing in the circumferential direction.

[0003] In existing assembly techniques, the assembly of ring-shaped components relies on manual hammering and adjustment, and it is impossible to observe the alignment of the ring-shaped component with the positioning holes. Furthermore, repeated hammering and adjustment during assembly can damage the ring-shaped component. Moreover, once a deviation occurs during assembly, the positioning components are difficult to disassemble without damage. These factors result in high difficulty and low efficiency in assembling ring-shaped components. Summary of the Invention

[0004] In view of the above-mentioned problems in the prior art, the present invention provides an assembly device for downhole tools, which can accurately assemble and disassemble annular components in the assembly operation of ultra-long deep holes.

[0005] The technical solution adopted by this invention to solve its technical problem is as follows: An assembly device for downhole tools is provided, including a housing, a fixed plate, and a telescopic assembly disposed on the housing. An adjusting member is disposed within the housing. The telescopic assembly is configured to engage with the adjusting member, so that the telescopic assembly can extend and retract radially via the adjusting member, thereby enabling the telescopic assembly, after passing through an annular component to be assembled, to jointly limit the annular component with the fixed plate. The housing is configured to extend into an ultra-long deep borehole of the downhole tool, so that the fixed plate and the telescopic assembly can assemble or detach the annular component at a target position within the ultra-long deep borehole.

[0006] Furthermore, the telescopic assembly includes a telescopic disc disposed on the housing and a telescopic block disposed on the telescopic disc, the telescopic block extending radially into the housing to engage with a first end of the adjusting member, the first end being configured to allow the telescopic block to move radially when moved axially relative to the housing.

[0007] Furthermore, the first end includes a conical surface that engages with the telescopic block, the conical surface being configured to allow the telescopic block to move radially outward when the large-diameter end of the first end moves toward the telescopic assembly, and to allow the telescopic block to move radially inward when the small-diameter end of the first end moves toward the telescopic assembly.

[0008] Furthermore, the second end of the adjusting member is screwed to the housing so that the first end moves relative to the housing in the axial direction when the adjusting member rotates relative to the housing.

[0009] Furthermore, the telescopic disc is provided with a mounting groove for mounting the telescopic block. The mounting groove is configured to limit the telescopic block in the axial direction while allowing the telescopic block to move in the radial direction.

[0010] Furthermore, the bottom of the mounting groove is provided with a through groove extending in the radial direction for accommodating the connecting part of the telescopic block, and an elastic element connected to the connecting part is provided in the through groove.

[0011] Furthermore, the housing is provided with a support member for supporting the housing when it leaves the ultra-long deep hole.

[0012] Furthermore, the support member is provided with a limiting groove for engaging with a limiting portion on the housing, so that the support member and the housing can be limited in the circumferential direction when the limiting portion is located in the limiting groove.

[0013] Furthermore, the outer wall of the support member is provided with threads for connecting the wall of the ultra-long deep hole when the support member and the housing form a circumferential limit.

[0014] Furthermore, the housing includes a first section for mounting the fixed plate and the telescopic assembly, and a second section connecting the first section. The second section is provided with an impact member for impacting the stepped surface between the first section and the second section, so as to assemble the annular component to the target position.

[0015] The beneficial effects of this invention lie in providing an assembly device for downhole tools, comprising a housing, a fixed plate, and a telescopic assembly disposed on the housing. An adjusting member is disposed within the housing. The telescopic assembly is configured to engage with the adjusting member, allowing it to extend and retract radially via the adjusting member. This enables the telescopic assembly, after passing through an annular component to be assembled, to work with the fixed plate to limit the annular component. The housing is configured to extend into an ultra-long, deep bore of the downhole tool, allowing the fixed plate and the telescopic assembly to assemble or disassemble the annular component at a target location within the ultra-long, deep bore. This assembly device can precisely assemble the annular component to the target location within the ultra-long, deep bore of the downhole tool, reducing assembly difficulty. Furthermore, the fixed plate can uniformly push the annular component during assembly, preventing damage and ensuring assembly quality. Similarly, the telescopic assembly can uniformly push the annular component during disassembly, ensuring its complete removal. Additionally, the assembly device allows real-time monitoring of the assembly process via a display and an endoscopic camera, ensuring installation quality. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0017] Figure 1 The image shown is a structural cross-sectional view of an assembly device for downhole tools.

[0018] Figure 2 As shown Figure 1 The structural cross-sectional view of the housing of the assembly device shown.

[0019] Figure 3 As shown Figure 1 The diagram shows the structural schematic of the support component of the assembly device.

[0020] Figure 4 As shown Figure 1 The diagram shows the structure of the adjustment tool of the assembly device.

[0021] Figure 5 As shown Figure 1 A schematic diagram of the telescopic disc of the telescopic assembly of the assembly device shown.

[0022] Figure 6 As shown Figure 1 A schematic diagram of the telescopic block of the telescopic assembly of the assembly device shown.

[0023] In the figures, the reference numerals are as follows: 100, assembly device; 10, housing; 11, first section; 111, limiting part; 12, second section; 121, stepped surface; 122, impact part; 13, support member; 131, limiting groove; 14, impact member; 15, through hole; 16, adjusting member; 161, first end; 1611, conical surface; 162, second end; 1621, adjusting part; 17, adjusting tool; 171, insertion hole; 172, handle; 18, opening; 20. Fixed plate; 30. Telescopic assembly; 31. Telescopic disc; 311. Mounting slot; 312. Through slot; 32. Telescopic block; 321. Connecting part; 40. Monitor; 50. Endoscopic camera. Detailed Implementation

[0024] To make the technical problem to be solved, the technical solution, and the beneficial effects of this invention clearer, the invention will now be described in detail with reference to the accompanying drawings. This drawing is a simplified schematic diagram, illustrating only the basic structure of the invention, and therefore only shows the components relevant to the invention. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0025] refer to Figure 1 As shown, the present invention provides an assembly device 100 for downhole tools, including a housing 10, a fixing plate 20 disposed on the housing 10, and a telescopic assembly 30 spaced apart from the fixing plate 20. The telescopic assembly 30 is configured to extend and retract in the radial direction to adjust the outer diameter of the telescopic assembly 30. This allows the outer diameter of the telescopic assembly 30 to be adjusted to be smaller than the inner diameter of the annular member to be assembled, enabling the annular member to be installed between the fixing plate 20 and the telescopic assembly 30. Then, the outer diameter of the telescopic assembly 30 can be adjusted to be larger than the inner diameter of the annular member, allowing the fixing plate 20 and the telescopic assembly 30 to limit the annular member in the axial direction. At this point, the annular member can be assembled by inserting the housing 10 into the extra-long deep hole of the downhole tool until the fixing plate 20 pushes the annular member to the target position in the extra-long deep hole. Alternatively, the annular member can be disassembled by removing the housing 10 from the extra-long deep hole of the downhole tool until the telescopic assembly 30 pushes the annular member out of the target position.

[0026] It should be understood that the ultra-long deep hole described in this application refers to a hole whose length is much greater than its inner diameter, and whose inner diameter is relatively small, for example, a length greater than 2.0m and an inner diameter less than 200mm.

[0027] It should be noted that the downhole tool in this application refers to a staged cementing device. It should be understood that the assembly device 100 in this application is not only applicable to downhole tools, but also to the assembly of tools with ultra-long, deep holes in other fields.

[0028] Combination Figure 1 and Figure 2 As shown, in some embodiments, the housing 10 is generally a tubular structure open at both ends. The outer diameter of the housing 10 is smaller than the inner diameter of the ultra-long deep hole so that the housing 10 can extend into the ultra-long deep hole.

[0029] In some embodiments, the housing 10 includes a first segment 11 for extending into an ultra-long deep hole, and a second segment 12 connected to the first segment 11. A support member 13 is provided at one end of the first segment 11 near the second segment 12 for connecting to the wall of the ultra-long deep hole, so as to ensure the coaxiality of the first segment 11 and the ultra-long deep hole when the first segment 11 is located in the ultra-long deep hole. Preferably, the support member 13 is generally annular. The inner wall of the support member 13 can be clearance-fitted with the outer wall of the first segment 11 so that the first segment 11 can slide and rotate relative to the support member 13. The outer wall of the support member 13 can connect to the wall of the ultra-long deep hole so that the support member 13 can reliably support the housing 10 and prevent the fixed disk 20 and the telescopic assembly 30 from shifting relative to the ultra-long deep hole.

[0030] In some preferred embodiments, the gap between the inner wall of the support member 13 and the outer wall of the first segment 11 is extremely small to ensure the coaxiality of the first segment 11 and the ultra-long deep hole throughout the assembly process. The outer wall of the support member 13 can be threaded to the hole wall of the ultra-long deep hole so that the support member 13 can effectively and reliably support the housing 10 during assembly and disassembly. More preferably, a limiting groove 131 is provided on the side surface of the support member 13 facing the second segment 12, and a limiting part 111 that mates with the limiting groove 131 is provided between the first segment 11 and the second segment 12. When the limiting part 111 is located in the limiting groove 131, a circumferential limitation is formed between the housing 10 and the support member 13. In this way, when the limiting part 111 is located in the limiting groove 131, the support member 13 can be threadedly connected to the hole wall of the ultra-long deep hole by rotating the housing 10. It should be understood that technicians can also rotate the support 13 independently when the limiting part 111 is not located in the limiting groove 131, so that the support 13 is threadedly connected to the wall of the ultra-long deep hole.

[0031] In this embodiment, two limiting parts 111 and two limiting grooves 131 are provided. The two limiting parts 111 are arranged opposite each other in the radial direction, and the two limiting grooves 131 are also arranged opposite each other in the radial direction.

[0032] In some other embodiments not shown, the limiting groove 131 may extend through the support 13 in the axial direction so that the housing 10 can extend further into the ultra-long deep hole when the limiting portion 111 is located in the limiting groove 131.

[0033] Combination Figure 1 and Figure 2 As shown, in some preferred embodiments, the outer diameter of the second segment 12 is smaller than that of the first segment 11, so as to form a stepped surface 121 between the second segment 12 and the first segment 11. An impact member 14 is provided on the second segment 12. The impact member 14 is configured to slide on the first segment 11 to adjust the distance the housing 10 extends into the ultra-long deep hole by impacting the stepped surface 121, thereby precisely assembling the annular member to the target position. More preferably, an impact portion 122 is provided at the end of the second segment 12 away from the first segment 11. The impact member 14 can also impact the impact portion 122, causing the housing 10 to move outward toward the ultra-long deep hole. In this way, the housing 10 can push the annular member out of the ultra-long deep hole during disassembly via the telescopic assembly 30.

[0034] Combination Figure 1 As shown, in some preferred embodiments, both the first segment 11 and the second segment 12 are provided with through holes 15 extending radially through, for wires electrically connecting the display 40 and the endoscope camera 50 to pass through. The endoscope camera 50 is mounted on the first segment 11, close to the fixing plate 20 and the telescopic assembly 30. This allows technicians to observe the position of the annular component in real time during assembly using the endoscope camera 50 and the display 40, ensuring that the annular component can be accurately assembled to the target position.

[0035] Combination Figure 1 As shown, in some embodiments, the housing 10 also includes an adjusting member 16 extending from the second segment 12 to the first segment 11. The first end 161 of the adjusting member 16 engages with the telescopic assembly 30. The second end 162 of the adjusting member 16 is located outside the extra-long deep hole, allowing a technician to manipulate the second end 162 to extend or retract the telescopic assembly 30 radially using the first end 161.

[0036] In some embodiments and implementations, the first end 161 is configured as a tapered structure, including a tapered surface 1611 that engages with the telescopic assembly 30. A technician can adjust the outer diameter of the telescopic assembly 30 by manipulating the second end 162 to move the first end 161 axially relative to the telescopic assembly 30. Specifically, when the larger diameter end of the first end 161 moves toward the telescopic assembly 30, the tapered surface 1611 guides the telescopic assembly 30 to extend radially outward, thereby increasing the outer diameter of the telescopic assembly 30. When the smaller diameter end of the first end 161 moves toward the telescopic assembly 30, the tapered surface 1611 guides the telescopic assembly 30 to extend radially inward, thereby decreasing the outer diameter of the telescopic assembly 30.

[0037] In some preferred embodiments and implementations, the outer surface of the second end 162 is provided with threads that screw into the inner wall of the second segment 12. When a technician rotates the adjusting member 16 relative to the housing 10 via the second end 162, the threads between the second end 162 and the second segment 12 guide the adjusting member 16 to move axially relative to the telescopic assembly 30. More preferably, the second end 162 is also provided with an adjusting portion 1621. The adjusting portion 1621 is configured to engage with an adjusting tool 17 so that a technician can rotate the adjusting member 16 via the adjusting tool 17.

[0038] In this embodiment, the adjustment part 1621 has a prism-shaped structure, preferably a square prism-shaped structure, a pentagonal prism-shaped structure, or a hexagonal prism-shaped structure. For example... Figure 4 As shown, the adjustment tool 17 is provided with a corresponding insertion hole 171 for the adjustment part 1621 to be inserted. More preferably, the adjustment tool 17 is also provided with a handle 172 for a technician to grip.

[0039] Combination Figure 1 As shown, in some embodiments, the fixing disc 20 is an annular structure sleeved on the first segment 11. The fixing disc 20 is connected to the first segment 11 by a threaded connection, allowing technicians to adjust the position of the fixing disc 20 on the first segment 11, as well as the distance between the fixing disc 20 and the telescopic component 30. This also allows the fixing disc 20 to push the annular component to the target position. It should be understood that the outer diameter of the fixing disc 20 is smaller than the diameter of the ultra-long deep hole, so that the fixing disc 20 can enter the ultra-long deep hole.

[0040] Combination Figure 1 , Figure 5 and Figure 6 As shown, in some embodiments, the telescopic assembly 30 includes a telescopic disc 31 and a telescopic block 32 disposed on the telescopic disc 31. The telescopic disc 31 is configured to limit the telescopic block 32 in the axial direction and allow the telescopic block 32 to move in the radial direction so that the telescopic assembly 30 can adjust its outer diameter.

[0041] In some embodiments, the telescopic disc 31 is also generally annular. The telescopic disc 31 has a plurality of radially extending mounting slots 311 for mounting various telescopic blocks 32. Each mounting slot 311 is radially opposite to an opening 18 on the first segment 11 of the housing 10, so that the telescopic blocks 32 within each mounting slot 311 can extend into the first segment 11 of the housing 10. This ensures that the end of the telescopic block 32 extending into the first segment 11 engages with the tapered surface 1611 of the first end 161.

[0042] Preferably, the telescopic disc 31 can be connected to the first section 11 of the housing 10 via threads. More preferably, each mounting groove 311 is a dovetail groove, so that the telescopic disc 31 can limit the telescopic block 32 in the mounting groove 311 in the axial direction.

[0043] Combination Figure 5 and Figure 6 As shown, in some preferred embodiments, the bottom of each mounting groove 311 is further provided with a radially extending through groove 312 for accommodating the connecting portion 321 of the telescopic block 32. An elastic element (not shown) connected to the connecting portion 321 is provided in the through groove 312, allowing the telescopic block 32 to move radially inward within the mounting groove 311. More preferably, the elastic element can be a tension spring provided in the through groove 312.

[0044] In some preferred embodiments, when the large-diameter end of the first end 161 moves toward the telescopic assembly 30, the conical surface 1611 guides each telescopic block 32 to move radially outward within the mounting groove 311, thereby increasing the outer diameter of the telescopic assembly 30. Simultaneously, each telescopic block 32 pulls on a corresponding elastic element, causing the elastic element to accumulate elastic potential energy. When the small-diameter end of the first end 161 moves toward the telescopic assembly 30, each elastic element releases its elastic potential energy and pulls each telescopic block 32 to move radially inward, thereby decreasing the outer diameter of the telescopic assembly 30.

[0045] Combination Figure 6 As shown, in some embodiments, each telescopic block 32 has a tapered arc surface at one end extending into the first segment 11 for tight engagement with the tapered surface 1611 of the first end 161. The end of each telescopic block 32 away from the first segment 11 is also provided with an arc surface for engagement with the wall of the ultra-long deep hole when the outer diameter of the telescopic assembly 30 is at its maximum.

[0046] The following is combined Figure 1-6 The assembly process of the assembly device 100 for downhole tools described above will be explained in detail.

[0047] First, rotate the adjusting member 16 to adjust the outer diameter of the telescopic assembly 30 to its minimum, so that the annular component to be assembled can pass through the telescopic assembly 30 and reach between the fixed plate 20 and the telescopic assembly 30. Then, rotate the adjusting member 16 in the opposite direction to increase the outer diameter of the telescopic assembly 30, so that the fixed plate 20 and the telescopic assembly 30 together provide axial restraint for the annular component. At this time, the fixed plate 20 is closer to the support member 13.

[0048] During the insertion of the first segment 11 of the housing 10 into the ultra-long deep hole, the support member 13 remains at the opening of the ultra-long deep hole. As the fixing plate 20 is about to push the annular member to the target position, the limiting part 111 partially enters the opening of the limiting groove 131. At this point, a technician can rotate the housing 10 to make the support member 13 threadedly connected to the wall of the ultra-long deep hole. Then, by sliding the impact member 14 on the second segment 12, the impact member 14 impacts the stepped surface 121 to further push the housing 10 into the ultra-long deep hole until the fixing plate 20 completely pushes the annular member to the target position.

[0049] At this point, the adjusting member 16 is rotated again to adjust the outer diameter of the telescopic component 30 to its minimum, so that the telescopic component 30 can pass through the annular member as the housing 10 leaves the ultra-long deep hole. During this process, the support member 13 always provides radial support to the housing 10, preventing the telescopic component 30 from deviating radially, thereby preventing the telescopic component 30 from touching the annular member as it leaves the ultra-long deep hole and ensuring the assembly quality of the annular member. When the fixed plate 20 and the telescopic component 30 reach the opening of the ultra-long deep hole, the support member 13 can be rotated independently so that the support member 13 is no longer screwed to the hole wall of the ultra-long deep hole. Thus, the assembly of the annular member is completed.

[0050] It should be understood that as long as the annular component is brought to the target position in the ultra-long deep hole by the assembly device 100, it can be considered as an assembly of the annular component. As for how the annular component is connected and fixed to the downhole tool with the ultra-long deep hole, it can be selected by those skilled in the art as needed.

[0051] In this embodiment and implementation, when the annular component reaches the target position, the annular component can be connected to the downhole tool via a shear pin that penetrates the wall of the ultra-long deep hole.

[0052] When it is necessary to disassemble the annular component in the ultra-long deep hole, the outer diameter of the telescopic assembly 30 needs to be adjusted to its minimum so that the telescopic assembly 30 can pass through the annular component as the housing 10 extends into the ultra-long deep hole. After the telescopic assembly 30 passes through the annular component, the outer diameter of the telescopic assembly 30 is increased to be greater than the inner diameter of the annular component by the adjusting member 16. At this time, the technician can push the annular component out of the ultra-long deep hole by moving the housing 10 outward.

[0053] It should be understood that as long as the annular component is moved away from the target position in the ultra-long deep hole by the assembly device 100, it can be regarded as the disassembly of the annular component.

[0054] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0055] It should be understood that the terms "length", "width", "up", "down", "front and back", "left and right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0056] Although the invention has been described with reference to preferred embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, the technical features mentioned in the various embodiments can be combined in any manner as long as there is no structural conflict. The invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. An assembly device for downhole tools, comprising, Housing (10), wherein an adjusting member (16) is provided inside the housing (10); and A fixed disc (20) and a telescopic assembly (30) are disposed on the housing (10). The telescopic assembly (30) is configured to engage with the adjusting member (16) so that the telescopic assembly (30) can extend and retract in the radial direction via the adjusting member (16), thereby enabling the telescopic assembly (30) to, together with the fixed disc (20), limit the annular member after passing through it. in, The housing (10) is configured to extend into the extra-long deep hole of the downhole tool so that the fixed plate (20) and the telescopic assembly (30) can be assembled or disassembled at a target location in the extra-long deep hole.

2. The assembly device according to claim 1, characterized in that, The telescopic assembly (30) includes a telescopic disc (31) disposed on the housing (10) and a telescopic block (32) disposed on the telescopic disc (31), the telescopic block (32) extending radially into the housing (10) to engage with a first end (161) of the adjusting member (16), the first end (161) being configured to allow the telescopic block (32) to move radially when moved relative to the housing (10) in an axial direction.

3. The assembly device according to claim 2, characterized in that, The first end (161) includes a conical surface (1611) that engages with the telescopic block (32), the conical surface (1611) being configured to allow the telescopic block (32) to move radially outward when the large-diameter end of the first end (161) moves toward the telescopic assembly (30), and to allow the telescopic block (32) to move radially inward when the small-diameter end of the first end (161) moves toward the telescopic assembly (30).

4. The assembly device according to claim 2, characterized in that, The second end (162) of the adjusting member (16) is screwed to the housing (10) so that the first end (161) moves axially relative to the housing (10) when the adjusting member (16) rotates relative to the housing (10).

5. The assembly device according to claim 2, characterized in that, The telescopic disc (31) is provided with a mounting groove (311) for mounting the telescopic block (32). The mounting groove (311) is configured to limit the telescopic block (32) in the axial direction, while allowing the telescopic block (32) to move in the radial direction.

6. The assembly device according to claim 5, characterized in that, The bottom of the mounting groove (311) is provided with a through groove (312) extending in the radial direction for accommodating the connecting part (321) of the telescopic block (32). An elastic element connected to the connecting part (321) is provided in the through groove (312).

7. The assembly apparatus according to any one of claims 1-6, characterized in that, A support member (13) is provided on the housing (10) for supporting the housing (10) when the housing (10) leaves the ultra-long deep hole.

8. The assembly apparatus according to claim 7, characterized in that, The support member (13) is provided with a limiting groove (131) for engaging with a limiting part (111) on the housing (10) so that the support member (13) and the housing (10) can be limited in the circumferential direction when the limiting part (111) is located in the limiting groove (131).

9. The assembly device according to claim 8, characterized in that, The outer wall of the support member (13) is provided with threads for connecting the wall of the ultra-long deep hole when the support member (13) and the housing (10) form a circumferential limit.

10. The assembly apparatus according to any one of claims 1-6, characterized in that, The housing (10) includes a first section (11) for mounting the fixed plate (20) and the telescopic assembly (30), and a second section (12) connecting the first section (11), wherein an impact member (14) is provided on the second section (12) for impacting the stepped surface (121) between the first section (11) and the second section (12) in order to assemble the annular component to the target position.

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