Bonding tool for composite material co-curing test plate

Abstract

The utility model discloses a bonding tool for a composite material co-curing test panel, which comprises an equipment bottom box, the top surface of the equipment bottom box is provided with a bearing groove in a penetrating manner, the inner bottom surface of the equipment bottom box is fixedly connected with a supporting column, the top end of the supporting column is fixedly connected with a supporting disc, the edge of the bearing groove in the top surface of the equipment bottom box is fixedly connected with a bearing ring, and the bearing ring is fixedly connected with a supporting plate. A bearing strip is arranged between the supporting disc and the bearing ring in the radial direction, an adjusting sliding groove is formed in the bearing strip in a penetrating mode, an adjusting sliding block is slidably connected into the adjusting sliding groove, and a clamping groove column is fixedly connected to the top face of the adjusting sliding block. The relative positions of the four groups of bearing strips and the positions of the clamping groove columns can be flexibly adjusted through the sliding fit of the bearing strips, the outer sliding grooves, the outer sliding blocks, the inner sliding grooves and the inner sliding blocks and the sliding of the adjusting sliding blocks in the adjusting sliding grooves.

Description

Technical Field

[0001] This utility model relates to the field of bonding tooling equipment technology, specifically a bonding tooling for composite material co-curing test plates. Background Technology

[0002] A composite co-curing test plate is an experimental specimen used to study and test the co-curing process and performance of composite materials. It is typically composed of two or more different composite material layers, cured under specific temperature, pressure, and time conditions to simulate the co-curing process of composite material structures in actual production. By conducting various performance tests on the co-curing test plate, such as mechanical properties and interfacial bonding performance, the feasibility of the co-curing process and optimization parameters can be evaluated, providing important reference for the design and manufacture of composite material structures. The bonding fixture used for the composite co-curing test plate is a specially designed device used to precisely position and fix the composite material components to be bonded during the preparation of the test plate, ensuring that they maintain the correct relative position and gap during bonding, while providing appropriate pressure and constraint to promote good adhesion of the adhesive under specified process conditions, thereby ensuring that the quality and performance of the co-curing test plate meet the test requirements.

[0003] Most existing composite material co-curing test plate bonding fixtures adopt fixed-size or fixed-shape clamping structures. This means that the equipment can only bond composite material co-curing test plates of a limited size. It is difficult to flexibly adjust the clamping structure according to the actual test plate size or shape, which limits the scope of equipment use. Multiple equipment are required to meet production needs, increasing production and usage costs. Utility Model Content

[0004] The purpose of this utility model is to provide a bonding fixture for composite material co-curing test plates in order to solve the above-mentioned problems existing in the prior art.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a bonding fixture for composite material co-curing test plates, comprising: a base box, a support groove extending through the top surface of the base box, a support column fixedly connected to the bottom surface inside the base box, a support plate fixedly connected to the top of the support column, a support ring fixedly connected to the edge of the support groove on the top surface of the base box, a support strip radially arranged between the support plate and the support ring, an adjusting groove extending through the support strip, an adjusting slider slidably connected inside the adjusting groove, a clamping groove column fixedly connected to the top surface of the adjusting slider, a connecting rod fixedly connected to one side of the adjusting slider, a collar fixedly connected to the end of the connecting rod, a hexagonal screw cylinder movably passing through the collar, two sets of fixing lugs fixedly connected to one side of the support strip, an adjusting screw fixedly connected between the two sets of fixing lugs, connecting rod grooves symmetrically extending through both ends of the inner side of the clamping adjusting groove, and a leveling frame fixedly connected to the top surface of the support strip.

[0006] As a further embodiment of this utility model: an outer sliding groove is provided on the inner side of the supporting ring, an inner sliding groove is provided on the outer side of the supporting plate, and an outer slider and an inner slider are respectively fixed to both ends of the supporting strip. The outer sliding groove and the outer slider are compatible in specifications and are slidably connected to each other. The inner sliding groove and the inner slider are compatible in specifications and are slidably connected to each other.

[0007] As a further embodiment of this utility model: The adjusting slider is symmetrically provided with the same number of connecting rods, collars, and hexagonal screw cylinders on both sides. An annular groove is provided on the outer side of the middle section of the hexagonal screw cylinder so that it can be movably inserted into the collar without dislodging. The supporting strip is symmetrically fixed with the same number of fixing lugs and adjusting screws at positions flush with the connecting rod groove on both sides. The adjusting screws and the hexagonal screw cylinders are screwed together to flexibly fix the adjusting slider in the adjusting groove.

[0008] As a further embodiment of this utility model: a spring groove is provided at one end of the support bar near the outer slider, a tension spring is fixedly connected to one end of the spring groove, a holding plate is fixedly connected to the other end of the tension spring, a positioning post is fixedly connected to one end of the holding plate, and a through groove is provided through the other end of the spring groove. Several sets of adjustment grooves are evenly arranged in a ring in the outer sliding groove inside the support ring. Under the elastic tension of the spring groove, the positioning post continuously passes through the through groove and extends into the corresponding adjustment groove to fix the position of the support bar between the support plate and the support ring.

[0009] As a further embodiment of this utility model: a support plate is fixedly connected to one side of the equipment base box, and an equipment top box is fixedly connected to the top of one side of the support plate. A hydraulic lifting column is installed on the bottom surface of the equipment top box, an installation plate is fixedly connected to the bottom end of the hydraulic lifting column, a rotating protrusion is fixedly connected to the bottom surface of the installation plate, and a rotating concave ring is provided on the outer side of the rotating protrusion for limiting.

[0010] As a further embodiment of this utility model: the outer top of the rotating concave ring is hinged to a pressure plate threaded tube, the pressure plate threaded tube is internally threaded with a pressure plate threaded rod, the outer bottom of the pressure plate threaded tube is hinged to a first hinge block, one end of the first hinge block is fixedly connected to an unfolding threaded tube, the outer bottom of the rotating concave ring is hinged to a second hinge block, one end of the second hinge block is rotatably connected to an unfolding threaded rod.

[0011] As a further embodiment of this utility model: the threaded tube of the pressure plate and the threaded rod of the pressure plate are screwed together and are in a telescopic connection state; the unfolded threaded tube and the unfolded threaded rod are also screwed together and are in a telescopic connection state.

[0012] Compared with the prior art, the beneficial effects of this utility model are:

[0013] 1. In this utility model, the relative positions of the four sets of support strips and the positions of the clamping groove columns can be flexibly adjusted by the sliding cooperation between the support strip and the outer slide groove, the outer slider, the inner slide groove and the inner slider, and the sliding of the adjusting slider in the adjusting slide groove. Regardless of the test plate of different shapes or specifications, it can be accurately adapted and stably clamped, which greatly expands the application range of the tooling and meets the diverse test plate bonding needs.

[0014] 2. In this utility model, a rotating concave ring is used as the basis, and a rotating convex column is used to realize the flexible rotation of the pressing structure. At the same time, by adjusting the extension and retraction of the pressure plate threaded tube and pressure plate threaded rod, and the unfolding threaded tube and unfolding threaded rod, the range and shape of the pressure plate structure covering the test plate can be flexibly changed, and the pressure angle and force applied to the test plate can be precisely controlled to ensure that test plates of different specifications and shapes can obtain uniform and effective pressure, which significantly improves the bonding quality of composite material co-curing test plates. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0016] Figure 2 This is a schematic diagram of the support column in this utility model;

[0017] Figure 3 This is a schematic diagram of the structure of the outer slider in this utility model;

[0018] Figure 4 This is a schematic diagram of the structure of the adjusting slider in this utility model;

[0019] Figure 5 This is a schematic diagram of the spring groove in this utility model;

[0020] Figure 6 This is a schematic diagram of the hydraulic lifting column in this utility model;

[0021] Figure 7 This is a schematic diagram of the rotating protrusion in this utility model;

[0022] Figure 8 This is a schematic diagram of the rotating concave ring in this utility model;

[0023] Figure 9 This is a structural schematic diagram of section A in this utility model, which is an enlarged view.

[0024] In the diagram: 1. Equipment base box; 2. Support groove; 3. Support column; 4. Support plate; 5. Support ring; 6. Outer slide groove; 7. Inner slide groove; 8. Support strip; 9. Outer slider; 10. Inner slider; 11. Adjusting slide groove; 12. Adjusting slider; 13. Clamping groove column; 16. Connecting rod groove; 17. Leveling frame; 18. Spring groove; 19. Tension spring; 20. Holding plate; 21. Positioning column; 22. Through groove; 23. 24. Adjustment groove; 25. Support plate; 26. Equipment top box; 27. Hydraulic lifting column; 28. Mounting plate; 29. ​​Rotating convex column; 30. Rotating concave ring; 31. Pressure plate threaded tube; 32. Pressure plate threaded rod; 33. Hinge block one; 34. Unfolding threaded tube; 35. Hinge block two; 36. Unfolding threaded rod; 37. Connecting rod; 38. Collar; 39. Hexagonal screw cylinder; 40. Fixed ear plate; 41. Adjusting screw. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0026] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not 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 this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. In the description of this utility model, it should be noted that unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "setting" 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 or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances. The embodiments of this utility model will be described below based on its overall structure.

[0027] Reference Figures 1 to 5 In this embodiment of the present invention, an adhesive bonding fixture for a composite material co-curing test plate includes: a base box 1, a support groove 2 extending through the top surface of the base box 1, a support column 3 fixedly connected to the bottom surface inside the base box 1, a support plate 4 fixedly connected to the top of the support column 3, a support ring 5 fixedly connected to the edge of the support groove 2 on the top surface of the base box 1, a support strip 8 radially arranged between the support plate 4 and the support ring 5, and an adjusting groove 11 extending through the support strip 8, allowing for sliding within the adjusting groove 11. An adjusting slider 12 is connected, and a clamping groove post 13 is fixedly connected to the top surface of the adjusting slider 12. A connecting rod 36 is fixedly connected to one side of the adjusting slider 12, and a collar 37 is fixedly connected to the end of the connecting rod 36. A hexagonal screw cylinder 38 is movably inserted inside the collar 37. Two sets of fixing ear plates 39 are fixedly connected to one side of the support strip 8, and an adjusting screw 40 is fixedly connected between the two sets of fixing ear plates 39. A connecting rod groove 16 is symmetrically opened through both ends of the inner side of the clamping adjusting groove 11, and a leveling frame 17 is fixedly connected to the top surface of the support strip 8.

[0028] Reference Figure 3 The inner side of the support ring 5 is provided with an outer sliding groove 6, and the outer side of the support plate 4 is provided with an inner sliding groove 7. The two ends of the support strip 8 are respectively fixed with an outer slider 9 and an inner slider 10. The outer sliding groove 6 and the outer slider 9 are compatible in specifications and are slidably connected to each other. The inner sliding groove 7 and the inner slider 10 are compatible in specifications and are slidably connected to each other.

[0029] Using the above scheme: the support strip 8 achieves flexible sliding between the support plate 4 and the support ring 5 through the structure of the outer sliding groove 6, the outer slider 9, the inner sliding groove 7, and the inner slider 10. This facilitates flexible adaptation to the clamping and stabilization requirements of test plates of different shapes by utilizing the variable relative positions of the four sets of support strips 8. The test plate is placed on the leveling frame 17 and the support plate 4, which are on the same horizontal plane.

[0030] Reference Figure 4 The adjusting slider 12 is symmetrically provided with the same number of connecting rods 36, collars 37 and hexagonal screw cylinders 38 on both sides. The outer side of the middle section of the hexagonal screw cylinder 38 is provided with an annular groove structure so that the hexagonal screw cylinder 38 can be moved through the collar 37 without falling out. The supporting strip 8 is symmetrically fixed with the same number of fixing ear plates 39 and adjusting screws 40 at the position flush with the connecting rod groove 16 on both sides. The adjusting screws 40 and the hexagonal screw cylinders 38 are screwed together to flexibly fix the position of the adjusting slider 12 in the adjusting groove 11.

[0031] The above scheme is adopted: the connecting rod 26 passes through the collar 37 fixed to the connecting rod groove 16 and the hexagonal screw cylinder 38 is movably inserted inside the collar 37. The hexagonal screw cylinder 38 is located inside the collar 37 and remains in a state of not coming out and can rotate flexibly. At the same time, the hexagonal screw cylinder 38 is sleeved on the adjusting screw 40 on the corresponding side and the two are screwed together. The structure of the two sets of symmetrical hexagonal screw cylinders 38 and adjusting screws 40 makes it easy to fix the adjusting slider 12 at any position in the adjusting groove 11, so that the clamping groove post 13 at the top of the adjusting slider 12 stably wraps around the corner of the test plate, that is, it can flexibly adapt to the clamping requirements of test plates of different specifications.

[0032] Reference Figure 2 and Figure 5 A spring groove 18 is provided at one end of the support bar 8 near the outer slider 9. A tension spring 19 is fixedly connected to one end of the spring groove 18, and a holding plate 20 is fixedly connected to the other end of the tension spring 19. A positioning post 21 is fixedly connected to one end of the holding plate 20, and a through groove 22 is provided through the other end of the spring groove 18. Several sets of adjustment grooves 23 are evenly arranged in a ring in the outer slider 6 inside the support ring 5. Under the elastic tension of the spring groove 18, the positioning post 21 continuously passes through the through groove 22 and extends into the corresponding adjustment groove 23 to fix the position of the support bar 8 between the support plate 4 and the support ring 5.

[0033] Using the above solution: The specific position of the support strip 8 between the support plate 4 and the support ring 5 is determined by the elastic tension of the tension spring 19 on the holding plate 20, so that the positioning post 21 passing through the through groove 22 is always in the state of being inserted into the corresponding adjustment groove 23, so as to conveniently fix the support strip 8. When it is necessary to readjust its position, simply press the holding plate 20 manually to compress the tension spring 19, so that the positioning post 21 can be disengaged from the corresponding adjustment groove 23.

[0034] Reference Figure 6 and Figure 7 A support plate 24 is fixedly connected to one side of the equipment base box 1. A top box 25 is fixedly connected to the top of one side of the support plate 24. A hydraulic lifting column 26 is installed on the bottom surface of the equipment top box 25. An installation plate 27 is fixedly connected to the bottom end of the hydraulic lifting column 26. A rotating protrusion 28 is fixedly connected to the bottom surface of the installation plate 27. A rotating concave ring 29 is provided on the outer side of the rotating protrusion 28 for limiting.

[0035] The above scheme is adopted: the structure of the pressing test plate is based on the rotating concave ring 29. The structure of the pressing test plate can be flexibly rotated through the rotating convex post 28 and the rotating concave ring 29 with matching specifications, thereby improving the applicability of the pressing test plate structure.

[0036] Reference Figure 8 and Figure 9 The outer top of the rotating concave ring 29 is hinged to the pressure plate threaded tube 30. The pressure plate threaded tube 30 is internally threaded to the pressure plate threaded rod 31. The outer bottom of the pressure plate threaded tube 30 is hinged to the first hinge block 32. One end of the first hinge block 32 is fixed to the unfolded threaded tube 33. The outer bottom of the rotating concave ring 29 is hinged to the second hinge block 34. One end of the second hinge block 34 is rotatably connected to the unfolded threaded rod 35. The pressure plate threaded tube 30 and the pressure plate threaded rod 31 are threaded together and are in a telescopic connection state. The unfolded threaded tube 33 and the unfolded threaded rod 35 are also threaded together and are in a telescopic connection state.

[0037] The above scheme is adopted: by rotating the threaded rod 31 of the pressure plate to adjust the extent of its extension out of the threaded tube 30 of the pressure plate, and by rotating the unfolding threaded rod 35 to adjust the extent of its extension out of the unfolding threaded tube 33, the distance and included angle of each set of threaded rods 31 of the pressure plate relative to the side of the rotating concave ring 29 can be adjusted so that the range and shape of the pressure plate structure covering the test plate can be flexibly adjusted to meet the requirement of uniform pressure on test plates of different specifications and shapes.

[0038] The working principle of this utility model is as follows: When in use, the test plate is first placed in the support groove 2 on the top surface of the equipment bottom box 1. The bottom of the test plate is supported by the leveling frame 17 and the support plate 4, which are on the same horizontal plane, to ensure that the test plate is placed stably.

[0039] When it is necessary to clamp and fix test plates of different shapes or sizes, on the one hand, the support strip 8 can slide flexibly radially between the support plate 4 and the support ring 5 through the sliding cooperation of the outer slider 9 and the outer slide groove 6, and the inner slider 10 and the inner slide groove 7. By adjusting the relative positions of the four sets of support strips 8, it can adapt to the clamping requirements of test plates of different shapes. When adjusting the position of the support strip 8, the holding plate 20 is subjected to the elastic tension of the tension spring 19, so that the positioning post 21 continuously passes through the through groove 22 and extends into the adjustment groove 23 to fix the position of the support strip 8. If it is necessary to readjust, manually press the holding plate 20 to compress the tension spring 19, so that the positioning post 21 is disengaged from the adjustment groove 23, and the support strip 8 can be moved. After the adjustment is completed, release the holding plate 20, and the positioning post 21 extends into the corresponding adjustment groove 23 again to fix it.

[0040] On the other hand, the adjusting slider 12 can be flexibly positioned and slidably adjusted within the adjusting groove 11 of the supporting strip 8. The connecting rods 26 on both sides of the adjusting slider 12 pass through the connecting rod groove 16 and are fixedly connected to the collar 37. The hexagonal screw cylinder 38 inside remains in a non-detached state and can rotate flexibly. At the same time, the hexagonal screw cylinder 38 is sleeved on the adjusting screw 40 on the corresponding side, and the two are screwed together. The structure of the two sets of symmetrical hexagonal screw cylinders 38 and adjusting screw 40 makes it easy to fix the adjusting slider 12 at any position in the adjusting groove 11, so that the clamping groove post 13 at the top of the adjusting slider 12 stably wraps around the corner of the test plate, that is, it can flexibly adapt to the clamping requirements of test plates of different specifications.

[0041] After the test plate is clamped and fixed, the hydraulic lifting column 26 on the bottom surface of the top box 25 of the equipment is activated, which drives the mounting plate 27, rotating protrusion 28 and rotating concave ring 29 to a suitable height close to the test plate. Since the rotating protrusion 28 and rotating concave ring 29 are fitted together, the structure of the pressed test plate can rotate flexibly, which enhances its applicability. Then, by rotating the pressure plate threaded rod 31 to adjust its length extending out of the pressure plate threaded tube 30, and by rotating the unfolding threaded rod 35 to adjust its length extending out of the unfolding threaded tube 33, the distance and angle between each set of pressure plate threaded rods 31 and the side of the rotating concave ring 29 are changed, so that the pressure plate structure can flexibly adjust the range and shape of the test plate to meet the requirements of uniform pressure on test plates of different specifications and shapes, and finally achieve effective bonding and fixing of the test plate, which helps the composite material co-curing process to proceed smoothly.

[0042] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A bonding fixture for composite material co-curing test plates, comprising: The equipment base box (1) is characterized in that a support groove (2) is provided through the top surface of the equipment base box (1), a support column (3) is fixedly connected to the bottom surface inside the equipment base box (1), a support plate (4) is fixedly connected to the top of the support column (3), a support ring (5) is fixedly connected to the edge of the support groove (2) on the top surface of the equipment base box (1), a support strip (8) is arranged radially between the support plate (4) and the support ring (5), an adjustment groove (11) is provided through the support strip (8), and an adjustment slider (12) is slidably connected inside the adjustment groove (11). The top surface of the slider (12) is fixed with a clamping groove column (13). A connecting rod (36) is fixed to one side of the adjusting slider (12). A collar (37) is fixed to the end of the connecting rod (36). A hexagonal screw cylinder (38) is movably inserted inside the collar (37). Two sets of fixed ear plates (39) are fixed to one side of the support strip (8). An adjusting screw (40) is fixed between the two sets of fixed ear plates (39). A connecting rod groove (16) is symmetrically opened through both ends of the clamping adjusting slide groove (11). A leveling frame (17) is fixed to the top surface of the support strip (8).

2. The bonding fixture for composite material co-curing test plates according to claim 1, characterized in that, The inner side of the support ring (5) is provided with an outer sliding groove (6), the outer side of the support plate (4) is provided with an inner sliding groove (7), and the two ends of the support strip (8) are respectively fixed with an outer slider (9) and an inner slider (10). The outer sliding groove (6) and the outer slider (9) are compatible in specifications and are slidably connected to each other. The inner sliding groove (7) and the inner slider (10) are compatible in specifications and are slidably connected to each other.

3. The bonding fixture for composite material co-curing test plates according to claim 1, characterized in that, The adjusting slider (12) is symmetrically provided with the same number of connecting rods (36), collars (37) and hexagonal screw cylinders (38) on both sides. The hexagonal screw cylinder (38) has an annular groove structure on the outer side of the middle section so that the hexagonal screw cylinder (38) can be moved through the collar (37) without falling out. The supporting strip (8) is symmetrically fixed with the same number of fixing ear plates (39) and adjusting screws (40) at the position flush with the connecting rod groove (16) on both sides. The adjusting screws (40) and the hexagonal screw cylinder (38) are screwed together to achieve flexible fixation of the adjusting slider (12) in the adjusting groove (11).

4. The bonding fixture for composite material co-curing test plates according to claim 1, characterized in that, The support strip (8) has a spring groove (18) at one end near the outer slider (9). A tension spring (19) is fixed to one end of the spring groove (18), and a holding plate (20) is fixed to the other end of the tension spring (19). A positioning post (21) is fixed to one end of the holding plate (20). A through groove (22) is opened through the other end of the spring groove (18). Several sets of adjustment grooves (23) are evenly arranged in a ring in the outer sliding groove (6) inside the support ring (5). Under the elastic tension of the spring groove (18), the positioning post (21) continuously passes through the through groove (22) and extends into the corresponding adjustment groove (23) to fix the position of the support strip (8) between the support plate (4) and the support ring (5).

5. The bonding fixture for composite material co-curing test plates according to claim 1, characterized in that, A support plate (24) is fixedly connected to one side of the equipment base box (1). A top box (25) is fixedly connected to the top of one side of the support plate (24). A hydraulic lifting column (26) is installed on the bottom surface of the equipment top box (25). An installation plate (27) is fixedly connected to the bottom end of the hydraulic lifting column (26). A rotating protrusion (28) is fixedly connected to the bottom surface of the installation plate (27). A rotating concave ring (29) is provided on the outer side of the rotating protrusion (28).

6. The bonding fixture for composite material co-curing test plates according to claim 5, characterized in that, The outer top of the rotating concave ring (29) is hinged to the pressure plate threaded tube (30), the pressure plate threaded tube (30) is internally threaded with the pressure plate threaded rod (31), the outer bottom of the pressure plate threaded tube (30) is hinged to the first hinge block (32), one end of the first hinge block (32) is fixedly connected to the unfolding threaded tube (33), the outer bottom of the rotating concave ring (29) is hinged to the second hinge block (34), one end of the second hinge block (34) is rotatably connected to the unfolding threaded rod (35).

7. The bonding fixture for composite material co-curing test plates according to claim 6, characterized in that, The pressure plate threaded tube (30) and the pressure plate threaded rod (31) are screwed together and are in a telescopic connection state. The unfolding threaded tube (33) and the unfolding threaded rod (35) are also screwed together and are in a telescopic connection state.

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