Sleeve structure

Abstract

The utility model discloses a sleeve structure which solves the problems that in the prior art, construction is affected due to the fact that a sleeve is too long, and the receiving risk of a short sleeve is large. The sleeve structure comprises a first sleeve and a second sleeve, the bottom of the first sleeve is supported through a first base, the bottom of the second sleeve is supported through a second base, a telescopic cylinder structure is arranged between the first sleeve and the second sleeve, and under the action of the telescopic cylinder structure, the second sleeve can longitudinally slide in a sealing mode along the first sleeve. The telescopic sleeve structure is arranged between the first sleeve and the second sleeve, so that the length of the sleeve is reduced, the synchronous construction space requirement is met, and the safety of the heading machine during receiving is guaranteed by the closed sleeve space.

Description

Technical Field

[0001] The utility model relates to the technical field of tunnel construction, in particular to a sleeve structure. Background Art

[0002] In order to speed up the formation of subway tunnels, the connecting channel and the main tunnel need to be constructed simultaneously. There are two methods for constructing the connecting channel: mechanical method and freezing method. Among them, the mechanical connecting channel is constructed by a tunnel boring machine. When the tunnel boring machine receives it, a sleeve structure needs to be arranged to ensure safety during reception.

[0003] In the prior art, such as the sleeve structure disclosed in the Chinese patent with publication number CN216691084U, this full-length sleeve structure will occupy the main tunnel space and cannot carry out synchronous construction. Therefore, it is necessary to design a short sleeve structure to receive and meet the synchronous construction space requirements. The Chinese patent with publication number CN206957717U proposes a shield to receive a micro steel sleeve. Although it can meet the synchronous construction space requirements, it is necessary to open the back cover to allow the tunnel boring machine to continue moving forward until it is received, which has the risk of leakage and poor safety. Therefore, it is necessary to design a sleeve structure for tunnel boring machine reception to solve the problems of sleeves being too long and short sleeves receiving high risks in the prior art. Utility Model Content

[0004] In view of the deficiencies in the above-mentioned background technology, the utility model proposes a sleeve structure, which solves the problems in the prior art that the sleeve is too long and affects the construction, and the short sleeve has a high receiving risk.

[0005] The technical solution of the utility model is implemented as follows: a sleeve structure includes a first sleeve and a second sleeve, the bottom of the first sleeve is supported by a first base, and the bottom of the second sleeve is supported by a second base, and a telescopic cylinder structure is provided between the first sleeve and the second sleeve. Under the action of the telescopic cylinder structure, the second sleeve can slide longitudinally along the first sleeve for sealing.

[0006] Further preferably, the first sleeve is a double-pass structure, and one end of the first sleeve is connected to the hole steel ring, and the other end is cooperatively connected to the second sleeve or the telescopic cylinder structure; the second sleeve is a single-pass structure, and the open end of the second sleeve is cooperatively connected to the first sleeve or the telescopic cylinder structure, and a removable top cover is provided at the closed end of the second sleeve.

[0007] Further preferably, the first base is an inwardly concave arc base, the inner arc surface of the inwardly concave arc base contacts and cooperates with the outer circumferential surface of the first sleeve; the second base is a slide rail base with two parallel sets, the slide rail base is detachably provided with a slide seat, and the second sleeve and / or the telescopic cylinder structure is slidably set on the slide rail base through the slide seat.

[0008] As a preferred embodiment, the telescopic cylinder structure includes an overlapping ring portion arranged on one side of the first sleeve, the outer diameter of the overlapping ring portion is equal to the outer diameter of the first sleeve and smaller than the inner diameter of the second sleeve, the overlapping ring portion is sleeved with the second sleeve, and the bottom of the overlapping ring portion is slidably matched with the second base through a detachable inclined frame.

[0009] Preferably, a sealing member in contact with the inner wall of the second sleeve is provided on the outer ring surface of the overlapping ring portion.

[0010] As a preferred embodiment, the telescopic cylinder structure includes an overlapping ring portion arranged on one side of the first sleeve and a double-pass sleeve arranged at the open end of the second sleeve. The outer diameter of the overlapping ring portion is equal to the outer diameter of the first sleeve and is smaller than the inner diameter of the double-pass sleeve. The overlapping ring portion is sleeved with the double-pass sleeve, and the bottom of the overlapping ring portion and the bottom of the double-pass sleeve are respectively slidably matched with the second base through a detachable inclined frame.

[0011] Preferably, a sealing member in contact with the inner wall of the double-pass sleeve is provided on the outer ring surface of the overlapping ring portion.

[0012] As a preferred embodiment, the telescopic cylinder structure includes a folding tube, one end of which is fixedly connected to the first sleeve and the other end is fixed to the opening end of the second sleeve; the bottom of the folding tube is slidably matched with the second base through a bracket.

[0013] Preferably, the outer diameter of the folded tube is equal to the outer diameter of the first sleeve, and the outer diameter of the first sleeve is equal to the outer diameter of the second sleeve.

[0014] As a preferred embodiment, the telescopic cylinder structure includes a folding tube and a double-way sleeve, one end of the folding tube is connected to the open end of the second sleeve, and the other end is fixedly connected to the double-way sleeve, the double-way sleeve is cooperatively connected to the first sleeve, the bottom of the folding tube is slidably matched with the second base through a bracket, and the bottom of the double-way sleeve is slidably matched with the second base through a detachable inclined frame.

[0015] Preferably, the outer diameter of the double-pass sleeve is equal to the outer diameter of the second sleeve, and the inner diameter of the double-pass sleeve is greater than the outer diameter of the first sleeve. The double-pass sleeve is sleeved with the first sleeve and a seal is provided between the two.

[0016] As a preferred embodiment, the telescopic cylinder structure includes an overlapping ring portion arranged on one side of the first sleeve and a folding tube arranged at the open end of the second sleeve, and a double-way sleeve is provided at one end of the folding tube facing the overlapping ring portion, and the double-way sleeve is sleeved and matched with the overlapping ring portion, and the bottom of the folding tube is slidably matched with the second base through a bracket, and the bottom of the double-way sleeve is slidably matched with the second base through a detachable inclined frame.

[0017] Preferably, the inner diameter of the double-pass sleeve is larger than the outer diameter of the overlapping ring portion, the outer diameter of the double-pass sleeve is equal to the outer diameter of the second sleeve, and a seal is provided between the double-pass sleeve and the overlapping ring portion.

[0018] The beneficial effects of the utility model are as follows: the utility model reduces the length of the sleeve by setting a telescopic cylinder structure between the first sleeve and the second sleeve, meets the space requirements for synchronous construction, and the closed sleeve space ensures the safety of the tunnel boring machine when receiving; it solves the problem in the prior art that the sleeve is too long to affect the construction, and the short sleeve has a high risk of receiving. The telescopic cylinder structure of the utility model is simple, ensuring sealing while achieving stable telescoping; by setting a compressible sleeve in the middle, the structure is simple and the operation is convenient, achieving the effect of rapid conversion between short and long sleeves; further improving the efficiency and safety of synchronous construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present utility model, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 This is a side view of the overlapping double sleeve structure of the utility model;

[0021] Figure 2 This is a side view of the structure of the overlapping double sleeves after contraction in Example 2;

[0022] Figure 3 This is a front view of the structure of the overlapping double sleeves after contraction in Example 2;

[0023] Figure 4 This is a side view of the structure after the overlapping three sleeves are deployed in Example 3;

[0024] Figure 5 This is a side view of the structure after the double sleeve plus the folding sleeve is collapsed in Example 5;

[0025] Figure 6 It is a side view schematic diagram of the structure after the overlapping double sleeves and folded tubes are unfolded in Example 6;

[0026] Figure 7 This is a side view of the structure after the double sleeves in Example 4 are connected by folding tubes and unfolded. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0028] like Figure 1 The embodiment 1 shown is a sleeve structure, including a first sleeve 1 and a second sleeve 2. The bottom of the first sleeve 1 is supported by a first base 4, and the first base 4 provides stable support for the first sleeve; the bottom of the second sleeve 2 is supported by a second base 5, and the second base 5 provides stable support for the second sleeve 2. A telescopic cylinder structure 3 is provided between the first sleeve 1 and the second sleeve 2. Under the action of the telescopic cylinder structure, the second sleeve 2 can slide longitudinally and sealed along the first sleeve 1. The utility model reduces the length of the sleeve by setting a telescopic cylinder structure to meet the space requirements for synchronous construction, and the closed sleeve space ensures the safety when the tunnel boring machine receives it. When the tunnel boring machine does not receive it, the telescopic cylinder structure can be retracted to ensure synchronous construction; when the tunnel boring machine receives it, the telescopic cylinder structure can be extended, and it can be gradually extended by the advancement of the tunnel boring machine, or it can be directly extended to the position at one time by pulling outward, and the combined length of the first sleeve and the second sleeve meets the receiving length of the tunnel boring machine.

[0029] As a preferred solution, the first sleeve 1 of this embodiment is a double-pass structure, that is, the first sleeve 1 is open at both ends. One end of the first sleeve 1 is connected to the hole steel ring, and the other end is connected with the second sleeve 2 or the telescopic cylinder structure; the second sleeve 2 is a single-pass structure, that is, the second sleeve 2 is open at one end, and the open end of the second sleeve 2 is connected with the first sleeve 1 or the telescopic cylinder structure. The first sleeve is stably connected to the hole door, and the second sleeve moves along the sleeve longitudinally through the telescopic part to achieve the effect of shortening the sleeve to achieve synchronous construction, and the sleeve is extended to achieve the effect of safely and airtightly receiving the tunnel boring machine. A detachable top cover is set at the closed end of the second sleeve 2. The first sleeve 1 is provided with a chamber door 11 and a pressure gauge 12; the chamber door 11 is an openable structure, and the pressure gauge is set at the top of the first sleeve for detecting the internal pressure. The second sleeve 2 is provided with a pressure relief valve 21 for pressure relief operation in the second sleeve.

[0030] As a preferred solution, the first base 4 of this embodiment is a concave arc base, and the inner arc surface of the concave arc base contacts and cooperates with the outer peripheral surface of the first sleeve 1, that is, the inner arc surface of the concave arc base has the same curvature as the first sleeve, so as to provide stable support for the first sleeve. The second base 5 is a two-way parallel slide rail base, and the two slide rail bases are arranged in an eight-shaped shape at the bottom of the second sleeve and the telescopic cylinder structure to provide stable support for them. The slide rail base is detachably provided with a slide seat 51, and the second sleeve 2 and / or the telescopic cylinder structure are slidably set on the slide rail base through the slide seat 51; the second sleeve 2 and the telescopic cylinder structure are smoothly slid. The second base is in the shape of a long strip, parallel to the first base in the plane, and a track is arranged on the upper part to facilitate the movement of the slider and the installation of the bracket and the inclined frame.

[0031] like Figure 2 , 3As shown, embodiment 2 is a sleeve structure. On the basis of embodiment 1, the telescopic cylinder structure 3 described in this embodiment adopts an overlapping double sleeve structure, which specifically includes a superimposed ring portion 31 arranged on one side of the first sleeve 1. The superimposed ring portion 31 can be a part of the first sleeve 1, or two separate components can be used for fixed connection. In this embodiment, the superimposed ring portion 31 is a part of the first sleeve 1. The outer diameter of the superimposed ring portion 31 is equal to the outer diameter of the first sleeve 1 and is smaller than the inner diameter of the second sleeve 2. The superimposed ring portion 31 is sleeved with the second sleeve 2, and the second sleeve can move relative to the superimposed ring portion to realize the telescopic design between the first sleeve and the second sleeve. And the bottom of the superimposed ring portion 31 is slidably matched with the second base 5 through a detachable inclined frame 52. When the tunnel boring machine receives it, the second sleeve 2 slides relative to the superimposed ring portion 31 to realize its extension, and then the detachable inclined frame 52 is installed at the bottom of the superimposed ring portion 31 to improve its stability.

[0032] In this embodiment, the length of the first base is half the length of the first sleeve, and is located at the connecting end of the first sleeve hole, and the length of the second base is the length of the first sleeve. The front section and the rear section of the second base can be separated, and the rear section can be installed and used when receiving. A sealing member in contact with the inner wall of the second sleeve 2 is provided on the outer ring surface of the overlapping ring portion 31. The sealing member can be a rubber ring or other annular seal. Preferably, the sealing member is arranged at the opening of the telescopic portion, that is, the end of the small diameter sleeve. When the two sleeves slide relative to each other, the sealing member is close to the smooth inner wall of the large diameter sleeve, and the sealing effect is better.

[0033] In this embodiment, the telescopic part is the overlapping area when the two sleeves are contracted. The two sleeves have different diameters, and one sleeve is embedded in the other sleeve. When contracted, the telescopic part is supported by the base of the large diameter sleeve. When extended, an inclined frame is set at the bottom of the telescopic part to connect and support it with the second base.

[0034] like Figure 4 As shown, embodiment 3 is a sleeve structure. The difference between this embodiment and embodiment 2 is that: the telescopic cylinder structure 3 adopts an overlapping three-sleeve structure, specifically including a superimposed ring portion 31 arranged on one side of the first sleeve 1 and a double-pass sleeve 32 arranged at the open end of the second sleeve 2; the superimposed ring portion 31 can be a part of the first sleeve 1, and the double-pass sleeve 32 can be a part of the double-pass sleeve 32, or it can be a separate annular cylinder fixed on the second sleeve, and arranged coaxially with the second sleeve. In this embodiment, a separate annular cylinder fixed on the second sleeve is taken as an example; the outer diameter of the superimposed ring portion 31 is equal to the outer diameter of the first sleeve 1 and is smaller than the inner diameter of the double-pass sleeve 32, and the superimposed ring portion 31 and the double-pass sleeve 32 are sleeved and matched; when the tunnel boring machine receives it, the double-pass sleeve 32 can slide relative to the superimposed ring portion 31 to realize the extension of the second sleeve. The bottom of the overlapping ring portion 31 and the bottom of the double-pass sleeve 32 are respectively slidably matched with the second base 5 through a detachable inclined frame 52 to improve the stability of the overlapping ring portion 31 and the double-pass sleeve 32 .

[0035] As a preferred solution, a seal is provided on the outer ring surface of the overlapping ring portion 31, which contacts the inner wall of the double-pass sleeve 32; the seal can be a rubber ring or other annular seal. Similarly, the sealing component is preferably arranged at the opening of the telescopic portion, that is, the end of the small-diameter sleeve. When the two sleeves slide relative to each other, the sealing component is in close contact with the smooth inner wall of the large-diameter sleeve, and the sealing effect is better.

[0036] In this embodiment, the telescopic part is a double-pass sleeve structure, and three sleeves are preferably used to slide relative to each other to further shorten the length of the sleeve structure. After unfolding, the telescopic part is connected to the second base support through a detachable inclined frame. The detachable inclined frame can be composed of a fixed plate and an inclined frame. The fixed plate is arranged on the area where the bottom of the double-pass sleeve overlaps with the second sleeve, and the fixed plate is connected to the second base through the inclined frame. In actual construction, the entire sleeve is shortened to 2 / 3, which cannot be met for smaller main tunnels. The number of sleeves can be increased to shorten the sleeve length. For example, the above-mentioned three-sleeve form is set to reduce the sleeve length to 1 / 2. The third sleeve is a double-pass structure, and the bottom is connected to the second base through an inclined frame to ensure the stability of the third sleeve when receiving.

[0037] like Figure 7 As shown, embodiment 4 is a sleeve structure. The difference between this embodiment and embodiment 2 is that the telescopic cylinder structure 3 adopts a double sleeve and a folding tube connection structure, specifically including a folding tube 33. The folding tube 33 can be a flexible folding tube, preferably a steel spring tube; it can be stretched and folded by external force. One end of the folding tube 33 is fixedly connected to the first sleeve 1 to ensure sealing, and the other end is fixed to the open end of the second sleeve 2 to ensure sealing. The bottom of the folding tube 33 is slidably matched with the second base 5 through the bracket 53; while improving the stability of the folding tube, it can slide smoothly to achieve rapid stretching and folding.

[0038] In this embodiment, as a preferred mode, the outer diameter of the folding tube 33 is equal to the outer diameter of the first sleeve 1, and the outer diameter of the first sleeve 1 is equal to the outer diameter of the second sleeve 2. In this embodiment, the cylinder with a compressible component in the middle is the folding tube, and the second sleeve is formed in an "accordion" style, with rigid parts at both ends, a slider connected to the bottom of the rigid part, and a spring part (such as a steel wire spring tube) in the middle. After unfolding, the bottom of the spring part is supported and stabilized by the bracket, and the entire sleeve is supported by the first base, the inclined frame, the bracket, and the slider. The inclined frame, the bracket, and the slider are supported by the second base and can slide relative to the second base. The diameters of the two sleeves can be the same, and the spring tube is connected between the two sleeves. The shortening and elongation of the sleeve structure is achieved by compressing and unfolding the spring tube.

[0039] like Figure 5As shown, embodiment 5 is a sleeve structure. The difference between this embodiment and embodiment 2 is that the telescopic cylinder structure 3 adopts a double sleeve plus folding cylinder structure, specifically including a folding tube 33 and a double-pass sleeve 32. One end of the folding tube 33 is connected to the open end of the second sleeve 2 to ensure sealing, and the other end is fixedly connected to the double-pass sleeve 32 to ensure sealing. The double-pass sleeve 32 is sealed and connected to the first sleeve 1. Under the action of the folding tube, the second sleeve slides relative to the first sleeve. The bottom of the folding tube 33 is slidably matched with the second base 5 through the bracket 53, and the bottom of the double-pass sleeve 32 is slidably matched with the second base 5 through the detachable inclined bracket 52; providing overall stability.

[0040] In this embodiment, as a preferred solution, the outer diameter of the double-pass sleeve 32 is equal to the outer diameter of the second sleeve 2, and the inner diameter of the double-pass sleeve 32 is larger than the outer diameter of the first sleeve 1, so as to achieve a sealed connection with the first sleeve. The double-pass sleeve 32 is sleeved with the first sleeve 1 and a seal is provided between the two. The seal can be a rubber ring or other annular seal.

[0041] like Figure 6 As shown, Example 6 is a sleeve structure. The difference between this example and Example 2 is that the telescopic cylinder structure 3 adopts a structure of overlapping double sleeves and folding tubes, which specifically includes a superimposed ring portion 31 arranged on one side of the first sleeve 1 and a folding tube 33 arranged at the open end of the second sleeve 2. The folding tube 33 preferably adopts a steel spring tube, and the steel spring tube is sealed and connected to the open end of the second sleeve 2. Similarly, the superimposed ring portion 31 can be a part of the first sleeve 1. A double-pass sleeve 32 is provided at one end of the folding tube 33 facing the superimposed ring portion 31. The double-pass sleeve 32 is sleeved and matched with the superimposed ring portion 31, and a sealed connection between the two is ensured. The bottom of the folding tube 33 is slidably matched with the second base 5 through a bracket 53, and the bottom of the double-pass sleeve 32 is slidably matched with the second base 5 through a detachable inclined bracket 52; to ensure stable support of the telescopic part.

[0042] As a preferred solution, the inner diameter of the double-pass sleeve 32 is larger than the outer diameter of the overlapping ring portion 31, the outer diameter of the double-pass sleeve 32 is equal to the outer diameter of the second sleeve 2, and a seal is provided between the double-pass sleeve 32 and the overlapping ring portion 31; the seal can be a rubber ring or other annular seal.

[0043] In this embodiment, a compressible sleeve is provided, which has a simple structure and convenient operation, and can achieve the effect of rapid conversion between the short sleeve and the long sleeve.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A sleeve structure, characterized in that: The invention comprises a first sleeve (1) and a second sleeve (2), wherein the bottom of the first sleeve (1) is supported by a first base (4), and the bottom of the second sleeve (2) is supported by a second base (5), and a telescopic cylinder structure (3) is provided between the first sleeve (1) and the second sleeve (2), and under the action of the telescopic cylinder structure, the second sleeve (2) can slide longitudinally and seal along the first sleeve (1).

2. The sleeve structure according to claim 1, characterized in that: The first sleeve (1) is a double-pass structure, and one end of the first sleeve (1) is connected to the hole steel ring, and the other end is connected to the second sleeve (2) or the telescopic cylinder structure; the second sleeve (2) is a single-pass structure, and the open end of the second sleeve (2) is connected to the first sleeve (1) or the telescopic cylinder structure, and the closed end of the second sleeve (2) is provided with a detachable top cover.

3. The sleeve structure according to claim 1, characterized in that: The first base (4) is an inwardly concave arc base, the inner arc surface of which contacts and cooperates with the outer peripheral surface of the first sleeve (1); the second base (5) is a two-way parallel slide rail base, the slide rail base is detachably provided with a slide seat (51), and the second sleeve (2) and / or the telescopic cylinder structure is slidably arranged on the slide rail base via the slide seat (51).

4. The sleeve structure according to claim 1 or 3, characterized in that: The telescopic cylinder structure (3) comprises a stacking ring portion (31) arranged on one side of the first sleeve (1); the outer diameter of the stacking ring portion (31) is equal to the outer diameter of the first sleeve (1) and smaller than the inner diameter of the second sleeve (2); the stacking ring portion (31) is sleeved and matched with the second sleeve (2), and the bottom of the stacking ring portion (31) is slidably matched with the second base (5) via a detachable inclined bracket (52); and a sealing member is provided on the outer ring surface of the stacking ring portion (31) and contacts the inner wall of the second sleeve (2).

5. The sleeve structure according to claim 1 or 3, characterized in that: The telescopic cylinder structure (3) comprises a stacking ring portion (31) arranged on one side of the first sleeve (1) and a double-pass sleeve (32) arranged at the open end of the second sleeve (2); the outer diameter of the stacking ring portion (31) is equal to the outer diameter of the first sleeve (1) and smaller than the inner diameter of the double-pass sleeve (32); the stacking ring portion (31) and the double-pass sleeve (32) are sleeved and matched, and the bottom of the stacking ring portion (31) and the bottom of the double-pass sleeve (32) are respectively slidably matched with the second base (5) via a detachable inclined bracket (52); and a sealing member is provided on the outer ring surface of the stacking ring portion (31) and contacts the inner wall of the double-pass sleeve (32).

6. The sleeve structure according to claim 1 or 3, characterized in that: The telescopic cylinder structure (3) comprises a folding tube (33), one end of the folding tube (33) being fixedly connected to the first sleeve (1) and the other end being fixed to the open end of the second sleeve (2); the bottom of the folding tube (33) is slidably matched with the second base (5) via a bracket (53); the outer diameter of the folding tube (33) is equal to the outer diameter of the first sleeve (1), and the outer diameter of the first sleeve (1) is equal to the outer diameter of the second sleeve (2).

7. The sleeve structure according to claim 1 or 3, characterized in that: The telescopic cylinder structure (3) comprises a folding tube (33) and a double-pass sleeve (32); one end of the folding tube (33) is connected to the open end of the second sleeve (2), and the other end is fixedly connected to the double-pass sleeve (32); the double-pass sleeve (32) is cooperatively connected to the first sleeve (1); the bottom of the folding tube (33) is slidably matched with the second base (5) via a bracket (53); and the bottom of the double-pass sleeve (32) is slidably matched with the second base (5) via a detachable inclined bracket (52).

8. The sleeve structure according to claim 7, characterized in that: The outer diameter of the double-pass sleeve (32) is equal to the outer diameter of the second sleeve (2), and the inner diameter of the double-pass sleeve (32) is greater than the outer diameter of the first sleeve (1). The double-pass sleeve (32) and the first sleeve (1) are sleeved and matched, and a sealing member is provided between the two.

9. The sleeve structure according to claim 1 or 3, characterized in that: The telescopic cylinder structure (3) comprises a stacking ring portion (31) arranged on one side of the first sleeve (1) and a folding tube (33) arranged at the open end of the second sleeve (2); a double-pass sleeve (32) is provided at one end of the folding tube (33) facing the stacking ring portion (31); the double-pass sleeve (32) is sleeved and matched with the stacking ring portion (31); the bottom of the folding tube (33) is slidably matched with the second base (5) via a bracket (53); and the bottom of the double-pass sleeve (32) is slidably matched with the second base (5) via a detachable inclined bracket (52).

10. The sleeve structure according to claim 9, characterized in that: The inner diameter of the double-pass sleeve (32) is greater than the outer diameter of the overlapping ring portion (31), the outer diameter of the double-pass sleeve (32) is equal to the outer diameter of the second sleeve (2), and a sealing member is provided between the double-pass sleeve (32) and the overlapping ring portion (31).

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