A high-rigidity, high-contraction-ratio columnar structure sealing box welding internal support fixture and its deployment and retraction method

Abstract

This invention belongs to the field of robotics mechanics, specifically relating to a high-rigidity, high-retraction-ratio cylindrical structure internal support fixture for box welding and its deployment and retraction method. It includes a central column and deformable components, which are spaced circumferentially along the central column. Each deformable component comprises a skeleton module and a support module, with the skeleton module connected between the central column and the support module. The internal support fixture sequentially changes between a first configuration, a second configuration, and a third configuration to achieve deployment-retraction conversion. Compared with existing technologies, this invention solves the problem that existing integrated internal support fixtures cannot simultaneously achieve high rigidity and high retraction ratio, thus failing to meet the requirements of box welding. The internal support fixture of this invention achieves a balance between high rigidity and high retraction ratio, exhibiting high rigidity and effective support during deployment, while maintaining a small diameter during retraction for easy removal from the flange hole, thus achieving a high retraction ratio.

Description

Technical Field

[0001] This invention belongs to the field of robotics mechanics, specifically relating to a high-rigidity, high-capacity cylindrical structure sealing box welding inner support fixture and its unfolding and retraction method. Background Technology

[0002] Heavy-lift launch vehicle fuel tanks are assembled using friction stir welding. The tanks themselves are cylindrical structures with relatively weak overall rigidity and poor resistance to deformation. During friction stir welding, the weld joints must withstand several tons of upward force. Therefore, internal support fixtures are needed at the weld joints to improve the tank structure's resistance to deformation. Specifically, after the final circumferential weld of the tank structure is completed—also known as the sealing weld—the internal support fixtures must be able to be removed through the flange openings. Taking the Long March 9 heavy-lift launch vehicle assembly as an example, the upward force at the weld joint can reach up to eight tons, but the deviation at the weld joint must be controlled within 0.2mm. Therefore, the internal support fixtures must possess very high rigidity in their deployed supporting state. Meanwhile, the Long March 9 carrier rocket has a diameter of 9.5m, while the flange orifice is only 0.9m. The radial dimension variation of the internal support clamp is more than 10. Therefore, the internal support clamp is required to have both high rigidity and high packing ratio.

[0003] In addition, existing internal support fixtures for sealing and welding cylindrical structures mostly adopt a manual disassembly design, which requires manual assembly, is time-consuming and labor-intensive, and has limited operating space. During the installation and debugging process, nuts and other parts may fall off and cause scratches or other damage to the inner wall. Therefore, there is an urgent need to develop automated fixture designs.

[0004] Existing umbrella-shaped clamp designs cannot adequately balance the requirements for both high rigidity and high collapsibility of the internal support clamp. Either the clamp lacks sufficient support rigidity when unfolded, or the collapsible clamp has a small collapsibility, making it difficult to remove from the flange hole.

[0005] CN212043117U discloses an internal support device for friction stir welding circumferential seam welding, including a central pressure plate, a telescopic nut, a left-handed screw, a right-handed screw, and a wedge block. The right-handed screw is connected to the central pressure plate, the left-handed screw is connected to the right-handed screw via the telescopic nut, and the wedge block is connected to the left-handed screw. The distance is adjusted by the telescopic nut, causing the wedge block to move and form a complete circle. However, the structural variation of this device is small and depends on the length of the telescopic nut and the distance between the left-handed and right-handed screws, making it difficult to simultaneously guarantee a high storage ratio and high rigidity. CN104785999A discloses a 5M-class tank sealing circumferential seam internal support device for rounding the sealing circumferential seam of the tank. It is supported by a support mechanism (lifting mechanism), which also makes it difficult to simultaneously guarantee a high storage ratio and high rigidity.

[0006] Currently, there is no design for an internal support fixture that can meet the requirements of sealing and welding cylindrical structures while possessing both high rigidity and high storage capacity. Therefore, there is an urgent need to propose an internal support fixture that can simultaneously achieve high rigidity and high storage capacity, while minimizing the use of fasteners. Summary of the Invention

[0007] The purpose of this invention is to provide a high-rigidity, high-retractability columnar structure sealing welding inner support fixture and its unfolding and retraction method to solve at least one of the above-mentioned problems. This solves the problem that the existing integrated inner support fixture cannot simultaneously achieve high rigidity and high retractability, thus failing to meet the usage requirements of sealing welding. The inner support fixture of this invention achieves a balance between high rigidity and high retractability. When unfolded, it has high rigidity and can form effective support, while when retracted, it has a small diameter and is easy to remove from the flange hole, thus achieving a high retractability.

[0008] The objective of this invention is achieved through the following technical solution:

[0009] The first aspect of the present invention discloses a columnar structure sealing box welding internal support fixture with high rigidity and high storage ratio, including a central column and deformable components, wherein the deformable components are arranged at intervals along the circumference of the central column.

[0010] The deformable component includes a skeleton module and a support module, wherein the skeleton module is connected between the intermediate column and the support module;

[0011] The skeleton module includes a first independent rod, a second independent rod, a first closed-loop rod, a second closed-loop rod, a third closed-loop rod, and a fourth closed-loop rod;

[0012] The first end of the first closed chain rod is hinged to the first end of the intermediate column, and the second end of the first closed chain rod is hinged to the support module; the fourth closed chain rod is disposed on the first closed chain rod.

[0013] The first end of the first independent rod is hinged to the first end of the middle column, and the second end of the first independent rod is detachably hinged to the first end of the fourth closed chain rod.

[0014] The first end of the second independent rod is hinged to the second end of the middle column, and the second end of the second independent rod is detachably hinged to the second end of the fourth closed chain rod.

[0015] The first end of the second closed chain rod is hinged to the first end of the middle column, and the second end of the second closed chain rod is hinged to the second end of the fourth closed chain rod.

[0016] The first end of the third closed chain rod is hinged to the first end of the fourth closed chain rod, and the second end of the third closed chain rod is hinged to the support module.

[0017] Preferably, the second end of the intermediate column has a groove at the position where it connects to the second independent rod, and the groove has space to accommodate the first end of the second independent rod.

[0018] Preferably, the intermediate column and the second independent rod are connected by a sleeve-type cylindrical joint.

[0019] Preferably, the support module is connected to the end of the skeleton module via an L-shaped connecting block.

[0020] Preferably, the L-shaped connecting block is composed of a first connecting plate and a second connecting plate, with the first connecting plate and the second connecting plate being arranged perpendicularly; the support module is hinged to the first connecting plate, and the skeleton module is hinged to the second connecting plate.

[0021] Preferably, the support module includes a first alignment rod and a second alignment rod; the first end of the first alignment rod is connected to the skeleton module, and the first end of the second alignment rod is hinged to the second end of the first alignment rod.

[0022] Preferably, both the first and second straightening rods are arc-shaped, and the arc of the first and second straightening rods is the same.

[0023] Preferably, the first alignment rod and the second alignment rod are connected by a cylindrical joint.

[0024] Preferably, the hinge is achieved through a revolute joint.

[0025] The second aspect of this invention discloses a method for unfolding and retracting a columnar structure sealing box welding inner support clamp with high rigidity and high storage ratio as described above, wherein the inner support clamp changes sequentially between a first configuration, a second configuration and a third configuration to achieve unfolding-retraction conversion;

[0026] In the first configuration: the first end of the first closed-chain rod is hinged to the first end of the intermediate column, and the second end of the first closed-chain rod is hinged to the support module; the fourth closed-chain rod is disposed on the first closed-chain rod; the first end of the first independent rod is hinged to the first end of the intermediate column, and the second end of the first independent rod is hinged to the first end of the fourth closed-chain rod; the first end of the second independent rod is hinged to the second end of the intermediate column, and the second end of the second independent rod is hinged to the second end of the fourth closed-chain rod; the first end of the second closed-chain rod is hinged to the first end of the intermediate column, and the second end of the second closed-chain rod is hinged to the second end of the fourth closed-chain rod; the first end of the third closed-chain rod is hinged to the first end of the fourth closed-chain rod, and the second end of the third closed-chain rod is hinged to the support module; each support module constitutes a ring structure centered on the intermediate column.

[0027] In the second configuration: the second end of the first independent rod is disconnected from the first end of the fourth closed chain rod, and the first independent rod rotates around the first end of the first independent rod until it is parallel to the axis of the middle column; the second end of the second independent rod is disconnected from the second end of the fourth closed chain rod, and the second independent rod rotates around the first end of the second independent rod until it is parallel to the axis of the middle column.

[0028] In the third configuration: the first closed chain rod, the second closed chain rod, the third closed chain rod, the fourth closed chain rod and the support module are in a linear structure, and the first closed chain rod rotates around the first end of the first closed chain rod until it is parallel to the axis of the middle column.

[0029] The working principle of this invention is as follows:

[0030] In the first configuration (fully deployed state): the members of the internal support clamp form a truss structure, and the support module is fully supported against the inner wall of the welding equipment to be sealed. The structural configuration of the skeleton module in this state is derived from a high-rigidity topology optimization design; therefore, the internal support clamp presents a fully deployed, high-rigidity support state.

[0031] In the second configuration (intermediate deformation state): the first independent rod and the second independent rod are disconnected from the fourth closed chain rod, so that each rod of the skeleton module has a degree of freedom of movement and regains its mobility;

[0032] In the third configuration: the connection between the second and fourth closed-loop links is changed from a hinged revolute joint to a prismatic joint. The RRRR (4 rotations) single closed-loop kinematic chain composed of the first, second, third, and fourth closed-loop links is converted into an RRR-P (3 rotations - 1 translation) configuration; (the length change of the fourth closed-loop link is achieved through the prismatic joint). The fourth closed-loop link can change its length, and the single closed-loop kinematic chain can be contracted into a linear shape. The support module moves towards the central column, disengaging from contact with the inner wall of the welding equipment to be sealed. At the same time, the spatial orientation of the support module can be adjusted by adjusting the hinge structure. Through the planning of the contraction movement, the inner support clamp can be radially contracted to the set constraint dimension space in the contracted state.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The topology and geometry of this internal support clamp skeleton module are specifically optimized simultaneously using high-rigidity truss topology optimization technology. Moreover, the self-stress mode of the rotating joint is relatively high, ensuring the high rigidity characteristics of the clamp when it is in a fully deployed and supported state.

[0035] All kinematic pairs in this mechanism are mainly revolute pairs, and all links are rigid. The structure is simple, lightweight, and has stable motion performance. It facilitates the drive control of the internal support clamp, enables the design of automated solutions, and has high reliability. Attached Figure Description

[0036] Figure 1 This is a structural diagram of the internal support clamp in the first configuration (fully deployed support configuration);

[0037] Figure 2 This is a schematic diagram of the internal support clamp in the second configuration.

[0038] Figure 3 This is a structural diagram of the internal support clamp in the first step of converting the second configuration to the third configuration.

[0039] Figure 4 This is a structural diagram of the second step in the conversion of the internal support clamp from the second configuration to the third configuration.

[0040] Figure 5 This is a schematic diagram of the internal support clamp in the third configuration (fully retracted configuration);

[0041] Figure 6 This is a schematic diagram of the L-shaped connecting block;

[0042] Figure 7 A schematic diagram of the structure in which the first closed chain rod and the first straightening rod are hinged to the L-shaped connecting block;

[0043] Figure 8 A schematic diagram of a sleeve-type cylindrical joint connecting the intermediate column and the second independent rod;

[0044] In the diagram: 1-Central column; 2-First independent rod; 3-Second independent rod; 4-First closed chain rod; 5-Second closed chain rod; 6-Third closed chain rod; 7-Fourth closed chain rod; 8-First alignment rod; 9-Second alignment rod; 10-L-shaped connecting block; 11-Sleeve cylindrical pair. Detailed Implementation

[0045] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0046] Example 1

[0047] A high-rigidity, high-density columnar structure sealing box welding internal support fixture, such as... Figure 1-8 As shown, it includes a central column and deformable components, wherein the deformable components are arranged at intervals along the circumference of the central column.

[0048] The deformable component includes a skeleton module and a support module, wherein the skeleton module is connected between the intermediate column and the support module;

[0049] The skeleton module includes a first independent rod, a second independent rod, a first closed-loop rod, a second closed-loop rod, a third closed-loop rod, and a fourth closed-loop rod;

[0050] The first end of the first closed chain rod is hinged to the first end of the intermediate column, and the second end of the first closed chain rod is hinged to the support module; the fourth closed chain rod is disposed on the first closed chain rod.

[0051] The first end of the first independent rod is hinged to the first end of the middle column, and the second end of the first independent rod is detachably hinged to the first end of the fourth closed chain rod.

[0052] The first end of the second independent rod is hinged to the second end of the middle column, and the second end of the second independent rod is detachably hinged to the second end of the fourth closed chain rod.

[0053] The first end of the second closed chain rod is hinged to the first end of the middle column, and the second end of the second closed chain rod is hinged to the second end of the fourth closed chain rod.

[0054] The first end of the third closed chain rod is hinged to the first end of the fourth closed chain rod, and the second end of the third closed chain rod is hinged to the support module.

[0055] A method for unfolding and retracting a high-rigidity, high-contraction-ratio columnar structure sealing box welding inner support clamp as described above, wherein the inner support clamp changes sequentially between a first configuration, a second configuration, and a third configuration to achieve unfolding-retraction conversion;

[0056] In the first configuration: the first end of the first closed-chain rod is hinged to the first end of the intermediate column, and the second end of the first closed-chain rod is hinged to the support module; the fourth closed-chain rod is disposed on the first closed-chain rod; the first end of the first independent rod is hinged to the first end of the intermediate column, and the second end of the first independent rod is hinged to the first end of the fourth closed-chain rod; the first end of the second independent rod is hinged to the second end of the intermediate column, and the second end of the second independent rod is hinged to the second end of the fourth closed-chain rod; the first end of the second closed-chain rod is hinged to the first end of the intermediate column, and the second end of the second closed-chain rod is hinged to the second end of the fourth closed-chain rod; the first end of the third closed-chain rod is hinged to the first end of the fourth closed-chain rod, and the second end of the third closed-chain rod is hinged to the support module; each support module constitutes a ring structure centered on the intermediate column.

[0057] In the second configuration: the second end of the first independent rod is disconnected from the first end of the fourth closed chain rod, and the first independent rod rotates around the first end of the first independent rod until it is parallel to the axis of the middle column; the second end of the second independent rod is disconnected from the second end of the fourth closed chain rod, and the second independent rod rotates around the first end of the second independent rod until it is parallel to the axis of the middle column.

[0058] In the third configuration: the first closed chain rod, the second closed chain rod, the third closed chain rod, the fourth closed chain rod and the support module are in a linear structure, and the first closed chain rod rotates around the first end of the first closed chain rod until it is parallel to the axis of the middle column.

[0059] More specifically, in this embodiment:

[0060] like Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 6 , Figure 7 and Figure 8 As shown, the cylindrical structure sealing box welding internal support fixture of this embodiment includes a central column 1, eight first independent rods 2, eight second independent rods 3, eight first closed chain rods 4, eight second closed chain rods 5, eight third closed chain rods 6, eight fourth closed chain rods 7, eight first straightening rods 8, eight second straightening rods 9, eight L-shaped connecting blocks 10, and eight sleeve-type cylindrical pairs 11. Among them, the first independent rods 2, second independent rods 3, first closed chain rods 4, second closed chain rods 5, third closed chain rods 6, and fourth closed chain rods 7 together constitute the skeleton module, and the first straightening rods 8 and second straightening rods 9 together constitute the support module.

[0061] In the internal support fixture described below, all hinges are achieved through revolute joints.

[0062] like Figure 1 and Figure 8 As shown, the central column 1 is cylindrical in shape, with eight skeleton modules connected to it via hinged revolute joints and sleeve-type cylindrical joints 11. Concave grooves are formed at the locations of the skeleton modules to accommodate their screwing in. The eight skeleton modules are arranged at equal 45-degree intervals along the circumference of the central column 1. Specifically: the hinged revolute joints are located within the cross-section of the central column 1 on the same plane (at the first end (bottom) of the central column 1), and the cylindrical shafts in the eight hinged revolute joints are respectively hinged to the first independent rod 2, the first closed-chain rod 4, and the second closed-chain rod 5 of the eight skeleton modules; the eight sleeve-type cylindrical joints 11 are arranged at equal 45-degree intervals along the circumference of the central column 1 on another plane (at the second end (top) of the central column 1), and the second independent rod 3 is hinged to each sleeve-type cylindrical joint 11 in a one-to-one correspondence. Notably, the axes of the sleeve-type cylindrical joints 11 and the revolute joints are parallel. At the location where the second independent rod 3 is connected to the middle column 1, a groove is provided at the location where the sleeve-type cylindrical part 11 is provided. This groove can accommodate the second independent rod 3, which has been rotated to be parallel to the central axis of the middle column 1 (the second independent rod 3 is pushed into the groove along the sleeve-type cylindrical part 11, so that the strip groove on the side wall of the middle column 1 is unobstructed).

[0063] The eight skeleton modules are structurally identical. Each skeleton module includes a first independent rod 2, a second independent rod 3, a first closed-link rod 4, a second closed-link rod 5, a third closed-link rod 6, and a fourth closed-link rod 7. The first independent rod 2, the first closed-link rod 4, and the second closed-link rod 5 are hinged together by a revolute joint of the intermediate column 1. The other end of the first independent rod 2 is hinged to the third closed-link rod 6 and the fourth closed-link rod 7. The other end of the first closed-link rod 4 is hinged to the third closed-link rod 6. The other end of the second closed-link rod 5 is hinged to the second independent rod 3 and the fourth closed-link rod 7. Figure 8 As shown, the sleeve-type cylindrical part 11 of the middle column is connected to one end of the second independent rod 3 of the skeleton module. In particular, the fourth closed chain rod 7 is located in the middle of the first closed chain rod 4; the two ends of the fourth closed chain rod 7 are respectively located on both sides of the first closed chain rod 4, and the middle part is fitted into the side of the first closed chain rod 4 through a curved structure. The connecting structure at both ends of the fourth closed chain rod 7 presses it onto the first closed chain rod 4.

[0064] like Figure 6 and 7 As shown, eight identical L-shaped connecting blocks 10 are used to hinge a skeleton module and a corresponding first alignment rod 8, respectively. The axes of the two rotational joints formed on the L-shaped connecting blocks 10 are offset perpendicularly. The first connecting plate constituting the L-shaped connecting block 10 is hinged to the first closed chain rod 4, and the second connecting plate is hinged to the first alignment rod 8.

[0065] The outer edges of the eight first-alignment rods 8 and the eight second-alignment rods 9 are all in a standard arc-shaped geometric shape, with a corresponding arc degree of 22.5 degrees. One end of the first-alignment rod 8 is hinged to the first closed-chain rod 4 through an L-shaped connecting block 10, and the other end is connected to the second-alignment rod 9 through a cylindrical joint.

[0066] By separating, fusing, and transforming the connecting joints, the skeleton module's topology can be changed, increasing its degrees of freedom and enabling switching between configurations and states to achieve the purpose of expansion and contraction. This internal support fixture can achieve three configuration transformations, thus possessing high rigidity performance in the fully expanded state and high storage ratio characteristics in the fully retracted state.

[0067] like Figure 1 As shown, the first configuration is in a fully deployed, supported state, exhibiting high stiffness. For example... Figure 2 It is the second configuration, which is the intermediate extended / retracted state of the internal support clamp. Figure 3 and Figure 4 The figures show two states of transition from the second configuration to the third configuration. In the third configuration, the internal support clamp can be completely retracted within the set radial space constraint, as shown below. Figure 5 As shown.

[0068] The working principle and unfolding / unfolding process of this internal support clamp for sealing and welding cylindrical structures are as follows:

[0069] In the first configuration, the skeleton module is a truss structure, with each member and structure mutually constrained and having zero mobility. At this point, the outer edges of all supporting modules form a standard circle, and the central axis of this standard circle coincides with the central axis of the central column 1. This structural configuration is derived from a high-stiffness topology optimization design and possesses high stiffness characteristics. First, analyzing the closing process, the eight first independent rods 2 disconnect from their hinged connections with the third closed-link rod 6 and the fourth closed-link rod 7, and can rotate around the revolute joint formed with the central column 1. The eight second independent rods 3 disconnect from their hinged connections with the second closed-link rod 5 and the fourth closed-link rod 7, and can rotate using the sleeve-type cylindrical joint 11 with the central column 1 to move accordingly. Based on the separation of these hinges, the internal support clamp transforms from the first configuration to the second configuration.

[0070] In the second configuration, the first independent rod 2 can rotate to a position parallel to the axis of the intermediate column 1, while the second independent rod 3 can rotate to a position parallel to the axis of the intermediate column 1. Furthermore, with the corresponding sleeve-type cylindrical pair 11 connected, the rotating shaft and the second independent rod 3 can be translated into the groove opened in the intermediate column 1. For example... Figure 2 As shown, when both the first independent rod 2 and the third independent rod 3 are parallel to the axis of the intermediate column 1, the second configuration can then be converted to the third configuration.

[0071] like Figure 3 As shown, during the transition to the third configuration, for each skeleton module, the hinged revolute joint between the second closed-loop link 5 and the fourth closed-loop link 7 is switched to a sliding joint, and the RRRR single closed loop composed of the first closed-loop link 4, the second closed-loop link 5, the third closed-loop link 6, and the fourth closed-loop link 7 is transformed into an RRR-P single closed loop. The eight skeleton modules achieve the transformation of the single closed-loop kinematic chain in two steps, with four modules transforming synchronously each time, and there should be a one-module interval between modules (i.e., interval synchronous transformation). During the skeleton module transformation, the first and second alignment rods 8 and 9 can be de-contacted with the inner wall of the welding equipment to be sealed. When the single closed-loop kinematic chain RRR-P moves to the collinear parallel convergence state of all the links (first closed-loop link 4, second closed-loop link 5, third closed-loop link 6, and fourth closed-loop link 7), the positions of the first alignment rod 8 and the second alignment rod 9 are adjusted, such as... Figure 4 and Figure 7As shown, by adjusting the cylindrical joint between the first adjusting rod 8 and the second adjusting rod 9, the end faces of the first adjusting rod 8 and the second adjusting rod 9 are separated, and they are rotated to a position where the chord lines of the outer arcs of the first adjusting rod 8 and the second adjusting rod 9 are approximately parallel. Rotating the revolute joint between the single closed-loop kinematic chain and the intermediate column 1 (the revolute joint connecting the first closed-loop rod 4 and the intermediate column 1) causes the single closed-loop kinematic chain to converge to a position parallel to the axis of the intermediate column 1 (just within the strip groove). Simultaneously, through the L-shaped connecting block 10 between the first closed-loop rod 4 and the first adjusting rod 8, the first adjusting rod 8 and the second adjusting rod 9 are also converged into the radial constraint space. After completing the convergence movement of all modules, the inner support fixture can be fully converged, as shown... Figure 5 As shown.

[0072] The unfolding process is the reverse of the retracting process. Specifically, when the RRR-P single closed-loop kinematic chain composed of the first closed-loop link 4, the second closed-loop link 5, the third closed-loop link 6, and the fourth closed-loop link 7 is transformed into the RRRR single closed-loop kinematic chain, the inner support clamp changes from the third configuration to the second configuration.

[0073] Compared with the prior art, the internal support fixture of the present invention has the characteristics of high rigidity and high storage ratio, which can meet the high rigidity performance requirements in the fully extended state and the high storage ratio in the fully retracted state. It realizes the automated tooling design of internal support fixtures suitable for sealing and welding cylindrical structures. At the same time, the internal support fixture has a simple structure, excellent motion performance, and is easy to control and maintain.

[0074] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A high-rigidity, high-contraction-ratio columnar structure sealing box welding inner support fixture, characterized in that, It includes a central column (1) and deformable components, wherein the deformable components are arranged at circumferential intervals along the central column (1); The deformable component includes a skeleton module and a support module, wherein the skeleton module is connected between the intermediate column (1) and the support module; The skeleton module includes a first independent rod (2), a second independent rod (3), a first closed chain rod (4), a second closed chain rod (5), a third closed chain rod (6), and a fourth closed chain rod (7); The first end of the first closed chain rod (4) is hinged to the first end of the middle column (1), and the second end of the first closed chain rod (4) is hinged to the support module; the fourth closed chain rod (7) is disposed on the first closed chain rod (4); The first end of the first independent rod (2) is hinged to the first end of the intermediate column (1), and the second end of the first independent rod (2) is detachably hinged to the first end of the fourth closed chain rod (7). The first end of the second independent rod (3) is hinged to the second end of the intermediate column (1), and the second end of the second independent rod (3) is detachably hinged to the second end of the fourth closed chain rod (7). The first end of the second closed chain rod (5) is hinged to the first end of the middle column (1), and the second end of the second closed chain rod (5) is hinged to the second end of the fourth closed chain rod (7). The first end of the third closed chain rod (6) is hinged to the first end of the fourth closed chain rod (7), and the second end of the third closed chain rod (6) is hinged to the support module.

2. The high-rigidity, high-accommodation-ratio columnar structure sealing and welding internal support fixture according to claim 1, characterized in that, The second end of the intermediate column (1) is provided with a groove at the position where the second independent rod (3) is connected, and the groove has space to accommodate the first end of the second independent rod (3).

3. The high-rigidity, high-accommodation-ratio columnar structure sealing box welding internal support fixture according to claim 2, characterized in that, The intermediate column (1) and the second independent rod (3) are connected by a sleeve-type cylindrical pair (11).

4. The high-rigidity, high-accommodation-ratio columnar structure sealing box welding inner support fixture according to claim 1, characterized in that, The support module is connected to the end of the skeleton module via an L-shaped connecting block (10).

5. The high-rigidity, high-accommodation-ratio columnar structure sealing box welding inner support fixture according to claim 4, characterized in that, The L-shaped connecting block (10) is composed of a first connecting plate and a second connecting plate, with the first connecting plate and the second connecting plate being arranged perpendicularly; the support module is hinged to the first connecting plate, and the skeleton module is hinged to the second connecting plate.

6. The high-rigidity, high-accommodation-ratio columnar structure sealing box welding internal support fixture according to claim 1, characterized in that, The support module includes a first alignment rod (8) and a second alignment rod (9); the first end of the first alignment rod (8) is connected to the skeleton module, and the first end of the second alignment rod (9) is hinged to the second end of the first alignment rod (8).

7. A high-rigidity, high-accommodation-ratio columnar structure sealing box welding inner support fixture according to claim 6, characterized in that, Both the first alignment rod (8) and the second alignment rod (9) are arc-shaped, and the first alignment rod (8) and the second alignment rod (9) have the same curvature.

8. A high-rigidity, high-accommodation-ratio columnar structure sealing box welding inner support fixture according to claim 6, characterized in that, The first alignment rod (8) and the second alignment rod (9) are connected by a cylindrical joint.

9. A high-rigidity, high-accommodation-ratio columnar structure sealing and welding inner support fixture according to any one of claims 1-8, characterized in that, The hinge is achieved through a revolute joint.

10. A method for extending and retracting a high-rigidity, high-contraction-ratio columnar structure sealing box welding inner support clamp as described in any one of claims 1-9, characterized in that, The internal support clamp changes sequentially between the first configuration, the second configuration, and the third configuration to achieve the unfolding-folding conversion; In the first configuration: the first end of the first closed-loop rod (4) is hinged to the first end of the intermediate column (1), and the second end of the first closed-loop rod (4) is hinged to the support module; the fourth closed-loop rod (7) is mounted on the first closed-loop rod (4); the first end of the first independent rod (2) is hinged to the first end of the intermediate column (1), and the second end of the first independent rod (2) is hinged to the first end of the fourth closed-loop rod (7); the first end of the second independent rod (3) is hinged to the second end of the intermediate column (1). The second end of the second independent rod (3) is hinged to the second end of the fourth closed chain rod (7); the first end of the second closed chain rod (5) is hinged to the first end of the middle column (1), and the second end of the second closed chain rod (5) is hinged to the second end of the fourth closed chain rod (7); the first end of the third closed chain rod (6) is hinged to the first end of the fourth closed chain rod (7), and the second end of the third closed chain rod (6) is hinged to the support module; each support module forms a ring structure centered on the middle column (1); In the second configuration: the second end of the first independent rod (2) is disconnected from the first end of the fourth closed chain rod (7), and the first independent rod (2) rotates around the first end of the first independent rod (2) until it is parallel to the axis of the middle column (1); the second end of the second independent rod (3) is disconnected from the second end of the fourth closed chain rod (7), and the second independent rod (3) rotates around the first end of the second independent rod (3) until it is parallel to the axis of the middle column (1); In the third configuration: the first closed chain rod (4), the second closed chain rod (5), the third closed chain rod (6), the fourth closed chain rod (7) and the support module are in a straight line structure. The first closed chain rod (4) rotates around the first end of the first closed chain rod (4) until it is parallel to the axis of the middle column (1).

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