An adjustable length lock seal pipe joint and method

Abstract

The application discloses a length-adjustable locking and sealing pipeline joint and method, and belongs to the technical field of fuel system pipe joints. The joint comprises a base, a bevel gear transmission mechanism, a rotating pipe, a translating pipe and a composite sealing head. The middle part of the base is provided with a bevel gear mounting seat, and the two sides are symmetrically provided with the rotating pipe. The rotating pipe is internally threadedly connected with the translating pipe. The rotating pipe and the base are sealed through an end face gasket. The composite sealing head comprises a sealing head gasket and a sealing nut. The sealing head gasket has a multi-section sealing structure and simultaneously forms multiple seals with the base clamping strips, the translating pipe clamping grooves and the rotating pipe inner wall. The tightening fastening nut simultaneously compresses the end face gasket and drives the sealing head gasket to radially expand through axial displacement, thereby realizing the synchronous locking and sealing between the rotating pipe and the base and between the rotating pipe and the translating pipe. The pipeline extension and contraction adjustment and multiple sealing can be completed through a single operation, and the application has the advantages of convenient operation, reliable sealing, no rotating torque transmission to the pipeline and the like.

Description

Technical Field

[0001] This invention belongs to the field of fuel system pipe fitting technology, specifically relating to an adjustable length locking and sealing pipe fitting and method. Background Technology

[0002] Unmanned aerial vehicles (UAVs) are widely used in agricultural plant protection, logistics and distribution, and other fields due to their small size, light weight, and high maneuverability. The fuel system of a UAV typically connects the fuel tank to the engine. Because of the compact size of the UAV, the length of the fuel lines needs to be adjusted urgently in special circumstances to accommodate different configurations; therefore, the fuel lines need to have a certain degree of flexibility and adjustability.

[0003] In existing technologies, expandable pipe fittings mostly employ threaded expansion structures or corrugated pipe structures. Threaded expansion structures achieve length adjustment by rotating the inner and outer pipes; however, this structure is relatively complex to operate, and because its two ends rotate relative to each other, the rotational torque is transmitted to the pipe, affecting sealing or fixation. While corrugated pipe structures have a certain degree of expansion and contraction, their pressure-bearing capacity is limited, and the amount of expansion and contraction is small. Furthermore, bending them occupies additional space, making them unsuitable for large-scale length adjustments.

[0004] Furthermore, drone fuel systems have extremely high requirements for sealing. Fuel leaks not only waste resources but can also cause safety accidents such as fires. Existing telescopic joints often require readjustment of the seal compression after length adjustment, which can easily lead to problems such as incomplete sealing or excessive tightness causing difficulty in rotation.

[0005] Therefore, it is necessary to develop a pipe fitting for drones that is easy to operate, reliably sealed, and allows for quick length adjustment. Summary of the Invention

[0006] The technical problem to be solved: To overcome the shortcomings of existing technologies, this invention provides an adjustable-length locking and sealing pipe connector and method. The pipe connector uses a bevel gear to drive a rotating tube, which in turn drives a translation tube to extend and retract axially, thus achieving length adjustment. The translation tube is circumferentially limited by a retaining strip, ensuring no torque is transmitted to the pipe during adjustment. This invention's connector, through its integrated design, allows length adjustment and locking sealing to be completed simultaneously, and its sealing structure provides multiple sealing effects, making it particularly suitable for unmanned aerial vehicle (UAV) fuel systems.

[0007] The technical solution of this invention is: an adjustable-length locking and sealing pipe joint, comprising: Base 1, as the supporting body, extends axially to both ends; Two rotating tubes 6 are rotatably fitted onto the two ends of the base 1, and their inner walls are provided with internal thread sections. Two translation tubes 7 are respectively inserted into two rotating tubes 6, and their outer walls are provided with external thread sections that mate with the internal thread sections of the rotating tubes 6; a circumferential limiting structure is provided between the translation tube 7 and the extension of the base 1, so that the translation tube 7 can only translate along the axial direction without relative rotation. A transmission mechanism is provided on the base 1 and is used to drive the rotating tubes 6 installed at both ends of the base 1 to rotate. Fasteners, placed on base 1, are used to apply axial preload; A sealing assembly is disposed between the rotating tube 6 and the translation tube 7, and between the rotating tube 6 and the base 1; When the fastener applies axial preload, the rotating tube 6 moves outward along the axial direction under the action of axial force, and synchronously drives the sealing assembly to generate radial expansion, so that multiple seals are formed between the rotating tube 6 and the base 1, and between the rotating tube 6 and the translation tube 7; when the fastener releases the axial preload, the rotating tube 6 is driven to rotate through the transmission mechanism, which in turn drives the translation tube 7 to translate along the axial direction, thereby realizing the adjustment of the pipeline length.

[0008] A further technical solution of the present invention is: the base 1 includes: Hollow connecting shaft 1-1 is a straight tubular structure of equal diameter with a hollow core. The base plate 1-2 is coaxially fixed to the outer periphery of the hollow connecting shaft 1-1 and located at the axial center. The outer periphery of the base plate 1-2 is a regular hexagon, which facilitates the use of tools to fix the base 1 during installation or maintenance. Multiple radial grooves are evenly distributed along the circumference of its outer periphery. The bottom surface of the groove is provided with a radially extending shaft 1-4. The bottom surface of the groove at the root of the shaft 1-4 is provided with a spring groove 1-5, and the top is provided with a shaft thread 1-6. Two small base discs 1-3 are coaxially fixed to the outer periphery of the hollow connecting shaft 1-1 and symmetrically arranged on both sides of the large base disc 1-2; a gasket groove 1-7 is provided on the opposite side of the large base disc 1-2 for installing the end face gasket 2; The base retaining strip 1-8 is a long, straight rod with both its inner and outer edges being arc-shaped and concentric with the base 1. Its inner diameter is slightly larger than the inner diameter of the hollow connecting shaft 1-1, so that the base retaining strip 1-8 does not occupy the pipeline channel. Multiple base retaining strips 1-8 are provided on both sides of the hollow connecting shaft 1-1 along the axial extension direction, and the base retaining strips 1-8 on both sides are symmetrically and evenly distributed, serving as the two end extensions of the base 1. The ends of the multiple base retaining strips 1-8 on the same side are processed into a stepped shape to form a slightly larger diameter end base retaining strip 1-9. The outer end of the end base retaining strip 1-9 is connected to a base sealing head threaded ring 1-10, which is coaxial with the hollow connecting shaft 1-1. The minor diameter of the thread of the base sealing head threaded ring 1-10 is consistent with the outer diameter of the end base retaining strip 1-9, forming a smooth transition.

[0009] A further technical solution of the present invention is: the transmission mechanism is a bevel gear transmission mechanism, including a bevel gear 3 and a spring 4. The bevel gear 3 is sleeved on the shaft 1-4, and the spring 4 is disposed between the bevel gear 3 and the root of the shaft 1-4, with its bottom embedded in the spring groove 1-5; The end face of the rotating tube 6 near the base plate 1-2 is provided with a bevel gear surface 6-1, which meshes with the teeth 3-2 of the bevel gear 3; The bevel gear transmission mechanism is used to ensure that the two rotating tubes 6 rotate synchronously in opposite directions. The bevel gear 3 can float axially along the shaft 1-4. When the fastener is released, the spring 4 pushes the bevel gear 3 away from the root, so that the axial force on the rotating tube 6 disappears, while maintaining the continuous meshing between the bevel gear 3 and the bevel gear surface 6-1. The bevel gear 3 has a gear spring groove 3-1 at the small diameter end of the shaft. One end of the spring 4 is embedded in the spring groove 1-5, and the other end is embedded in the gear spring groove 3-1, so that both ends of the spring 4 are radially positioned to prevent the spring 4 from radially shifting during compression.

[0010] A further technical solution of the present invention is: the rotating tube 6 is a hollow tubular structure, and is provided sequentially from one end near the base plate 1-2 towards the other end: The small disc cavity 6-3 has a two-stage central through hole. The small diameter section is fitted onto the hollow connecting shaft 1-1 between the large base disc 1-2 and the small base disc 1-3. The inner diameter of the large diameter section matches the outer diameter of the small base disc 1-3, allowing the rotating tube 6 to rotate around the small base disc 1-3. The axial depth of the small disc cavity 6-3 is slightly greater than the thickness of the small base disc 1-3, giving the rotating tube 6 a certain axial movement space to generate axial displacement when the fastener applies axial preload, thereby squeezing the sealing assembly. The fit between the inner wall of the large diameter section of the small disc cavity 6-3 and the outer diameter of the small base disc 1-3 simultaneously limits the maximum axial displacement of the rotating tube 6, preventing the rotating tube 6 from coming off. The end face of the small diameter section is provided with a bevel gear surface 6-1. The threaded cavity 6-4 has one end detachably connected to the small disc cavity 6-3, and the inner wall of the middle section is machined with internal threads to form the threaded cavity 6-4, which mates with the external thread 7-1 of the translation tube; the other end is provided with a base retaining strip cavity 6-6 and a sealing head cavity 6-7, which are used to accommodate the end of the base retaining strip 1-8 and part of the sealing assembly structure. The rotating tube 6 has a hexagonal screwing part 6-5 on the outside corresponding to the threaded cavity 6-4, which makes it easy to rotate the rotating tube 6 with tools such as wrenches.

[0011] A further technical solution of the present invention is: the translation tube 7 is a thin-walled tubular structure with a uniform inner diameter, and its outer surface is provided with: The external thread 7-1 of the translation tube is located at one end of the translation tube 7 near the base plate 1-2 and is installed in conjunction with the threaded cavity 6-4 of the rotating tube 6. The translation tube retaining groove 7-2 is an axial groove set on the outer surface of the translation tube 7. Multiple translation tube retaining grooves 7-2 are evenly distributed around the circumference of the translation tube 7. The axial length of the translation tube retaining groove 7-2 is greater than the axial length of the external thread 7-1 of the translation tube. It covers the external thread area and extends towards the end of the translation tube 7, so that the sealing recess 8-3 of the sealing head gasket 8 keeps in contact with the surface of the translation tube 7 when the translation tube 7 is in any extended position, maintaining an effective seal. The number and cross-sectional shape are consistent with the base retaining strip 1-8. It slides with the base retaining strip 1-8 along the axial direction and restricts the circumferential rotation of the translation tube 7 relative to the base 1. The external thread 7-1 of the translation tube is divided into multiple discontinuous external thread beams 7-3 along the circumferential direction by the translation tube retaining groove 7-2. The number of thread beams 7-3 is the same as the number of translation tube retaining grooves 7-2, so that the thread fit and circumferential restriction are realized in the same axial section. Pipe connector 7-4 is located at the end of the translation pipe 7 and is used to connect to external pipes.

[0012] A further technical solution of the present invention is: the sealing assembly includes an end face gasket 2 and a composite sealing head; The end face gasket 2 is disposed between the base small disc 1-3 and the inner end face of the small disc cavity 6-3 of the rotating tube 6. The cross-section of the end face gasket 2 is convex, and the protruding part is embedded in the base gasket groove 1-7 for positioning. When under pressure, the deformation is constrained by the groove, thereby improving the sealing effect. The composite sealing head includes a sealing head gasket 8 and a sealing nut 9; The main body of the sealing head gasket 8 is an annular structure. Its outer ring is provided with a wedge surface 8-1, which fits against the inner wall of the sealing head cavity 6-7 of the rotating tube 6. Its inner ring is divided into a large inner ring 8-2 and a small inner ring along the axial direction. The large inner ring 8-2 is located on the side away from the base 1, and the small inner ring is located on the side close to the base 1. The stepped sealing surface 9-2 of the sealing nut 9 fits against the end face of both the large inner ring 8-2 and the end face of the small inner ring, axially defining the position of the sealing head gasket 8. The small inner ring is provided with multiple sealing protrusions 8-4 along the circumference. A sealing recess 8-3 is formed between adjacent sealing protrusions. The arc length of the sealing protrusion 8-4 is slightly larger than the width of the translation tube clamping groove 7-2. When embedded in the translation tube clamping groove 7-2, sealing is achieved by compression. The sealing protrusion 8-4 has an axial retaining strip hole 8-5 inside for inserting the base retaining strip 1-8; The inner ring of the sealing nut 9 is provided with a sealing head thread 9-1, which is installed in conjunction with the sealing head thread ring 1-10 of the base; its outer ring is provided with a sealing head stepped sealing surface 9-2, which is in contact with the end faces of the large inner ring 8-2 and the small inner ring of the sealing head gasket 8.

[0013] A further technical solution of the present invention is: the far end of the sealing protrusion 8-4 near the axis is connected to the main body of the sealing head gasket 8 only through the sealing protrusion connecting part 8-6, and the remaining part of the sealing protrusion 8-4 forms a suspended structure with the main body, so that the radial force can be transmitted to the front end of the sealing protrusion 8-4 through the sealing protrusion connecting part 8-6. The arc length of the sealing protrusion 8-4 is greater than the arc length of the locking strip hole 8-5. The middle part of the far end of the sealing protrusion 8-4 is provided with a sealing protrusion installation seam 8-7, which is convenient for being fitted onto the base locking strip 1-8.

[0014] A further technical solution of the present invention is: the fastener is a fastening nut 5, which is disposed on the shaft 1-4, and its internal thread is fitted with the shaft thread 1-6; When the fastening nut 5 is tightened, the spring 4 is compressed, the bevel gear 3 is pushed to the root of the shaft 1-4, and the rotating tube 6 is moved outward by axial force, so that the end face gasket 2 and the sealing head gasket 8 are squeezed and deformed to form a seal. When the fastening nut 5 is loosened, the spring 4 returns to its original deformation, the bevel gear 3 moves away from the root of the shaft 1-4, the axial force on the rotating tube 6 disappears, and the compression deformation of the end face gasket 2 and the sealing head gasket 8 is restored. The upper length of the pipeline joint can be adjusted by rotating the rotating tube 6. A sealing method for an adjustable-length locking and sealing pipe joint, comprising: Locking and sealing: Tightening the locking nut 5 compresses the spring 4, pushes the bevel gear 3 to the root of the shaft 1-4, and causes the rotating tube 6 to move outward along the axial direction under axial force, producing the following multiple sealing effects: (a) The inner end face of the small disc cavity 6-3 of the rotating tube 6 is pressed against the end face gasket 2 to achieve a seal between the rotating tube 6 and the base 1; (b) The sealing head cavity 6-7 of the rotating tube 6 presses the wedge surface 8-1 of the sealing head gasket 8, so that the wedge surface 8-1 is tightly fitted with the inner wall of the sealing head cavity 6-7; (c) The radial deformation of the wedge surface 8-1 under pressure causes the sealing recess 8-3 to fit tightly against the surface of the translation tube 7, and at the same time causes the surface of the clip hole 8-5 away from the axis to fit tightly against the base clip 1-8; (d) The radial force is transmitted to the front end of the sealing protrusion 8-4 through the sealing protrusion connection 8-6, so that the sealing protrusion 8-4 is tightly fitted with the inner wall of the translation tube clamp groove 7-2; (e) After the sealing protrusion 8-4 is embedded in the translation tube clamping groove 7-2, the reaction force generated by the translation tube clamping groove 7-2 on the sealing protrusion 8-4 causes the surface of the clamping hole 8-5 near the axis to form a seal between it and the base clamping strip 1-8. Together with the seal of the surface of the clamping hole 8-5 away from the axis on the base clamping strip 1-8, it constitutes a bidirectional clamping seal on the base clamping strip 1-8. (f) The sealing nut 9, which has been tightened during assembly, has a stepped sealing surface 9-2 that axially defines the position of the large inner ring 8-2 and the small inner ring end face of the sealing head gasket 8, thus assisting in achieving a seal; Length adjustment: Loosen the fastening nut 5. Under the elastic force of the spring 4, the bevel gear 3 moves away from the root of the shaft 1-4, the axial force on the rotating tube 6 disappears, and the compression deformation of the end face gasket 2 and the sealing head gasket 8 is restored. Rotate the rotating tube 6, and drive the two rotating tubes 6 to rotate synchronously in opposite directions through the transmission mechanism. Drive the translation tube 7 to translate axially through the threaded engagement to realize the adjustment of the pipeline length. During the adjustment process, the translation tube 7 only translates axially without rotating under the restriction of the base clamp strips 1-8. Reset seal: After adjusting to the target length, tighten the locking nut 5 again. The rotating tube 6 is once again subjected to axial force and moves outward. The end face gasket 2 and the sealing head gasket 8 are once again squeezed and deformed, restoring the multiple sealing state in the locking seal.

[0015] A further technical solution of the present invention is: during the length adjustment, when the translation tube 7 extends outward, the sealing recess 8-3 of the sealing head gasket 8 always remains in contact with the surface of the translation tube 7 to maintain an effective seal; The extreme position where the translation tube 7 extends outward is the position where the end of the external thread 7-1 of the translation tube contacts the sealing head gasket 8.

[0016] Beneficial effects The beneficial effects of this invention are as follows: This invention uses bevel gear transmission to the pipe joint, achieving synchronous telescopic adjustment on both sides; a single operation triggers multiple seals, solving the problem of step-by-step operation for adjustment, locking, and sealing in traditional joints; the structure is compact, making it particularly suitable for rapid connection in the confined spaces of UAVs. Specific effects are analyzed below: 1. In this invention, the translation tube and the base are circumferentially limited by the clamp strip. When adjusting the length, the translation tube only moves horizontally and does not rotate. The rotational torque only acts on the rotating tube and the base and will not be transmitted to the pipeline system, thus avoiding the risk of pipeline torsion damage. It is particularly suitable for fixed pipeline connections.

[0017] 2. The sealing head gasket of this invention adopts a multi-segment structure, forming multiple sealing paths with the inner wall of the rotating tube, the groove of the translation tube clamping strip, and the base clamping strip. During radial expansion, the sealing force can be transmitted to the front end of the sealing protrusion, so that the sealing protrusion and the groove of the translation tube clamping strip form a tight fit. Even if the sealing area changes after the translation tube moves, it can still maintain an effective seal, avoiding the problems of easy aging and single-point failure of traditional sealing rings.

[0018] 3. This invention can simultaneously lock and seal the rotating tube and the base, and the rotating tube and the translation tube by tightening or loosening the fastening nut in the middle of the base in a single operation. This eliminates the need to operate multiple sealing components separately, greatly simplifying the operation process and making it particularly suitable for the rapid connection of UAVs in confined spaces.

[0019] 4. The wedge-shaped structure of the sealing head gasket of this invention, combined with the radial expansion principle, makes the sealing force proportional to the axial preload. The tighter it is tightened, the better the sealing effect, avoiding the problems of difficulty in rotation due to excessive sealing or leakage due to insufficient sealing.

[0020] 5. This invention integrates the length adjustment mechanism, locking mechanism, and multiple sealing mechanism into one unit, resulting in a compact overall structure that occupies little space and meets the design requirements of lightweight and miniaturized UAVs. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of an adjustable-length locking and sealing pipe joint assembly structure according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the base 1 structure in an embodiment of the present invention; Figure 3 This is a schematic diagram of the end face gasket 2 structure in an embodiment of the present invention; Figure 4 This is a schematic diagram of the bevel gear 3 structure in an embodiment of the present invention; Figure 5 This is a schematic diagram of the spring 4 structure in an embodiment of the present invention; Figure 6 This is a schematic diagram of the fastening nut 5 in an embodiment of the present invention; Figure 7 This is a schematic diagram of the rotating tube 6 in an embodiment of the present invention; Figure 8 This is a schematic diagram of the translation tube 7 structure in an embodiment of the present invention; Figure 9 This is a schematic diagram of the sealing head gasket 8 in an embodiment of the present invention; Figure 10 This is a schematic diagram of the sealing nut 9 in an embodiment of the present invention; Explanation of reference numerals in the attached drawings: 1. Base 1; 1-1. Hollow connecting shaft; 1-2. Large base disc; 1-3. Small base disc; 1-4. Shaft; 1-5. Spring groove; 1-6. Shaft thread; 1-7. Base gasket groove; 1-8. Base retaining strip; 1-9. End base retaining strip; 1-10. Threaded ring of base sealing head; 2. End face gasket; 3. Bevel gear; 3-1. Gear spring groove; 3-2. Gear; 4. Spring; 5. Fastening nut; 6. Rotating tube; 6-1. Bevel gear surface; 6-2. Large end inlet of rotating tube; 6-3. Small disc cavity; 6-4. Threaded cavity; 6-5. 6-6. Tightening part; 6-7. End base retaining strip cavity; 6-8. Sealing head cavity; 7-9. Small disc cavity thread; 7-1. Translation tube; 7-2. Translation tube retaining strip groove; 7-3. Translation tube external thread beam; 7-4. Pipe connector; 8. Sealing head gasket; 8-1. Wedge surface; 8-2. Large inner ring; 8-3. Sealing recess; 8-4. Sealing protrusion; 8-5. Retaining strip hole; 8-6. Sealing protrusion connection part; 8-7. Sealing protrusion installation seam; 9. Sealing nut; 9-1. Sealing head thread; 9-2. Sealing head stepped sealing surface; 9-3. Hexagonal nut head. Detailed Implementation The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the invention, and should not be construed as limiting the invention.

[0022] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention 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 invention.

[0023] To address the problems existing in the prior art, this invention discloses an adjustable-length locking and sealing pipe joint, comprising: Base 1, as the supporting body, extends axially to both ends; Two rotating tubes 6 are rotatably fitted onto the two ends of the base 1, and their inner walls are provided with internal thread sections. Two translation tubes 7 are respectively inserted into two rotating tubes 6, and their outer walls are provided with external thread sections that mate with the internal thread sections of the rotating tubes 6; a circumferential limiting structure is provided between the translation tube 7 and the extension of the base 1, so that the translation tube 7 can only translate along the axial direction without relative rotation. A transmission mechanism is provided on the base 1 and is used to drive the rotating tubes 6 installed at both ends of the base 1 to rotate. Fasteners, placed on base 1, are used to apply axial preload; A sealing assembly is disposed between the rotating tube 6 and the translation tube 7, and between the rotating tube 6 and the base 1; When the fastener applies axial preload, the rotating tube 6 moves axially under the action of axial force, and at the same time drives the sealing assembly to generate radial expansion, so that multiple seals are formed between the rotating tube 6 and the base 1, and between the rotating tube 6 and the translation tube 7; when the fastener releases the axial preload, the rotating tube 6 is driven to rotate through the transmission mechanism, which in turn drives the translation tube 7 to translate axially, thereby realizing the adjustment of the pipeline length.

[0024] The above technical solution will be further analyzed below with reference to the accompanying drawings and examples: Reference Figure 1 As shown, this embodiment provides a telescopic pipe joint, including a base 1, two rotating pipes 6, two translating pipes 7, a bevel gear transmission mechanism, fasteners, and a composite sealing head.

[0025] Reference Figure 2 As shown, base 1 serves as the main support for the entire connector, and its structural design balances strength and functional integration. Base 1 has a hexagonal mounting plate in the center, called the large base plate 1-2. This polygonal design facilitates tooling for securing the base during installation or maintenance. Two smaller base plates 1-3 are coaxially connected to both sides of the large base plate 1-2. The diameter of these two smaller plates is slightly smaller than that of the large base plate, and their structure and position are symmetrical along the axial direction. The large base plate 1-2 and the smaller base plates 1-3 are connected by a hollow connecting shaft 1-1, the inner diameter of which is the inner diameter of the pipeline channel.

[0026] The base plate 1-2 has three evenly spaced grooves around its circumference, with a radially extending shaft 1-4 positioned in the center of each groove. A spring groove 1-5 is located at the root of the shaft 1-4 (the end closest to the center of the base plate), and a shaft thread 1-6 is machined at the top of the shaft 1-4. Base gasket grooves 1-7 are located on the inner sides of the two small base plates 1-3 (i.e., the side facing the base plate). These grooves are used to install end face gaskets 2 with a convex cross-section (such as...). Figure 3 (As shown).

[0027] Three base retaining strips 1-8 are evenly distributed circumferentially on the base 1, extending to both sides from the positions of the small base discs 1-3. The inner and outer edges of the base retaining strips 1-8 are arc-shaped concentric with the base, and their inner diameter is slightly larger than the inner diameter of the hollow connecting shaft 1-1 to ensure that the strips themselves do not obstruct the pipeline passage. The end of the base retaining strip 1-8 (the end furthest from the large base disc) is machined into a stepped shape, forming a slightly larger diameter end base retaining strip 1-9. The outer end of the end base retaining strip 1-9 is connected to an annular base sealing head threaded ring 1-10. The minor diameter of the internal thread of this threaded ring is consistent with the outer diameter of the end base retaining strip 1-9, forming a smooth transition.

[0028] The bevel gear transmission mechanism ensures that the two rotating tubes 6 rotate synchronously in opposite directions. Specifically, on each shaft 1-4 of the base plate 1-2, a spring 4, a bevel gear 3, and a fastening nut 5 are sequentially mounted from the inside out. (Refer to...) Figure 4 As shown, the smaller diameter side of the bevel gear 3 has a hollowed-out center to form a gear spring groove 3-1. One end of the spring 4 is installed in the spring groove 1-5 at the root of the shaft, and the other end is installed in the gear spring groove 3-1. A fastening nut 5 (as shown) Figure 6 (As shown) It engages with the shaft thread 1-6 to lock the position of the bevel gear 3 and apply preload. The teeth 3-2 of the bevel gear 3 are always engaged with the bevel gear surface 6-1 on the end face of the rotating tube 6.

[0029] Reference Figure 5 As shown, the stiffness of spring 4 satisfies the following conditions: the sealing assembly does not leak when the fastener is fully tightened, and the manual operating torque of the fastener is within a reasonable range.

[0030] Two rotating tubes 6 are respectively fitted onto the small base discs 1-3 on both sides of the base 1. (Refer to...) Figure 7As shown, the rotating tube 6 is a hollow tubular structure with its two ends having a diameter slightly larger than the middle section to accommodate different functional structures. The large-diameter end face of the rotating tube 6 is machined into a bevel gear surface 6-1, and the hole at the center of this end face serves as the large-end inlet 6-2 of the rotating tube. Extending inwards is a smaller disc cavity 6-3 with an even larger diameter. The inner diameter of this cavity matches the outer diameter of the base small disc 1-3, allowing the rotating tube 6 to rotate around the base small disc 1-3. The depth of the small disc cavity 6-3 is slightly greater than the thickness of the base small disc 1-3 to ensure that the rotating tube 6 has a certain axial movement space. Further inwards from the small disc cavity 6-3 (towards the end) is a threaded cavity 6-4, with a diameter smaller than that of the small disc cavity 6-3. The inner wall of the threaded cavity 6-4 is machined with an internal thread, the length of which is slightly greater than half the length of the threaded cavity 6-4, for mating with the external thread of the translation tube 7. The outer part of the rotating tube 6, corresponding to the threaded cavity 6-4, is designed in a hexagonal shape, forming a screwing part 6-5, which facilitates the rotation of the rotating tube using tools such as wrenches. The threaded cavity 6-4 extends to the small-diameter end of the rotating tube 6. Inside the end, there are an end base retaining strip cavity 6-6 and a sealing head cavity 6-7. The inner diameter of both cavities is larger than the inner diameter of the threaded cavity 6-4 to accommodate the end of the base retaining strip and part of the composite sealing head structure. The small disc cavity 6-3 is a detachable structure, connected by the small disc cavity thread 6-8 for easy assembly.

[0031] Two translation tubes 7 are respectively inserted into the corresponding rotating tubes 6. (Refer to...) Figure 8 As shown, the translation tube 7 is a thin-walled pipe with a uniform inner diameter, ensuring smooth internal fuel passage. The outer surface of the translation tube 7 is divided into several functional areas: starting from one end near the base, approximately half of its length is machined with external threads 7-1; approximately four-fifths of its length (covering the external thread area and extending outwards) is machined with axially evenly distributed translation tube retaining grooves 7-2. The cross-sectional shape and distribution of these retaining grooves match the base retaining strips 1-8, but the width of the grooves is much larger than the width of the base retaining strips. At another section of the external thread 7-1, the translation tube retaining grooves 7-2 divide the translation tube circumferentially into three segments; these divided protruding segments are called the external thread beams 7-3. The end of the translation tube 7 is a pipe connector 7-4, used to connect to external pipes.

[0032] The composite sealing head is one of the core innovations of this invention, comprising a sealing head gasket 8 and a sealing nut 9.

[0033] Reference Figure 9As shown, the main body of the sealing head gasket 8 is an annular structure, made of a material with certain elasticity and oil resistance (such as fluororubber). Its outer ring is machined with a wedge surface 8-1, the angle of which matches the taper of the inner wall of the sealing head cavity 6-7 of the rotating tube 6. After installation, the wedge surface 8-1 fits into the sealing head cavity 6-7. The inner ring of the sealing head gasket 8 is divided into two sections along the axial direction: a larger inner ring 8-2 on the side away from the base, and a smaller inner ring on the side closer to the base. Three sealing protrusions 8-4 are evenly distributed circumferentially on the smaller inner ring. The projection shape and size of the sealing protrusions 8-4 on a plane perpendicular to the axis are basically the same as the translation tube clamping groove 7-2. The difference is that the arc length of the sealing protrusions 8-4 is 1.1 to 1.3 times the width of the translation tube clamping groove 7-2. After installation, the sealing protrusions 8-4 undergo elastic deformation under compression, tightly fitting against the inner wall of the translation tube clamping groove 7-2 to achieve a seal. After installation, each sealing protrusion 8-4 fits perfectly into the corresponding translation tube retaining groove 7-2. Each sealing protrusion 8-4 has a retaining hole 8-5 inside (radially outwards). The projection shape and size of this retaining hole on a plane perpendicular to the axis are completely identical to the base retaining strip 1-8. After installation, the base retaining strip 1-8 passes through the retaining hole 8-5. The small inner ring, excluding the area with the three sealing protrusions 8-4, consists of a sealing recess 8-3 circumferentially. The arc length (circumferential length) of the sealing protrusion 8-4 is much greater than the arc length of its internal retaining hole 8-5. The far end of the sealing protrusion 8-4 near the axis (i.e., the innermost radial end) is connected to the main body of the sealing head gasket 8 via the sealing protrusion connecting part 8-6. This design allows radial force to be transmitted to the front end of the sealing protrusion through the connecting part. A sealing protrusion mounting slot 8-7 is cut in the middle of the far end of the sealing protrusion for easy fitting onto the base retaining strip.

[0034] Reference Figure 10 As shown, the main body of the sealing nut 9 is a nut structure. The inner ring is machined with a sealing head thread 9-1, which mates with the base sealing head threaded ring 1-10. The inner side of the outer ring of the sealing nut 9 (the side closest to the base) is machined with a stepped sealing surface 9-2, which fits against the end faces of the large inner ring 8-2 and the small inner ring of the sealing head gasket 8. The outer side of the outer ring of the sealing nut 9 has a hexagonal nut head 9-3 for easy tightening with tools.

[0035] Except for the base 1, the bevel gear transmission mechanism, and the fasteners, all other parts of the joint are in pairs and are arranged symmetrically along the axial direction, with identical structure and function.

[0036] Installation process: Before leaving the factory, first unscrew the thread 6-8 of the small disc cavity, put the end face gasket 2 and the small disc cavity 6-3 onto the hollow connecting shaft 1-1, and then put on the base plate 1-2 and weld it in place. After installing the translation tube 7 into the corresponding position, weld on the base clip 1-8.

[0037] During installation, screw the other part of the rotating tube 6 onto the small disc cavity thread 6-8, and then install the sealing head gasket 8 (which is fitted onto the base clip 1-8 through the sealing protrusion installation seam 8-7) and the sealing nut 9 in sequence.

[0038] The expandable pipe joint of the present invention has two working states during use: Locked and sealed state: such as Figure 1 In steps (b) and (c), tighten the three fastening nuts 5, compress the spring 4, and push the bevel gear 3 to the root of the shaft 1-4 and make it touch the bottom. At this time, the bevel gear surfaces 6-1 of the two rotating tubes 6 are squeezed by the bevel gear 3, generating an axial force away from the center of the base. This axial force causes the inner end face of the small disc cavity 6-3 of the rotating tube 6 to press against the end face gasket 2, causing the gasket to undergo a slight deformation, thus achieving a seal between the small disc 1-3 of the base and the small disc cavity 6-3. Simultaneously, because the sealing nut 9 is in a tightened state, the sealing head gasket 8 is compressed and undergoes multi-directional deformation: the wedge surface 8-1 is pressed against the inner wall of the sealing head cavity 6-7, achieving a seal at that point; the radial inward deformation generated by the wedge surface 8-1 after being compressed causes the sealing recess 8-3 to fit tightly against the external threaded beam 7-3 (or the smooth rod section) of the translation tube 7, achieving a seal; this radial deformation also causes the surface of the retaining strip hole 8-5 away from the axis to fit tightly against the base retaining strip 1-8, achieving a seal; since the arc length of the sealing protrusion 8-4 is much larger than that of the retaining strip hole 8-5, the radial force generated by the compression of the wedge surface 8-1 passes through the sealing protrusion connecting part 8-6 The force is transmitted to the end of the sealing protrusion 8-4 near the axis. Since the arc length of the distal end of the sealing protrusion is slightly greater than the arc length of the translation tube retaining groove, the sealing protrusion 8-4 fits more tightly against the inner wall of the translation tube retaining groove 7-2 during compression, achieving a seal on the groove itself. Simultaneously, the reaction force of the translation tube retaining groove 7-2 on the sealing protrusion 8-4 further seals the surface of the retaining hole 8-5 near the axis with the base retaining strip 1-8. The already tightened sealing nut 9, with its stepped sealing surface 9-2 axially limiting the position of the sealing head gasket 8, compresses the end faces of the large inner ring 8-2 and the small inner ring, assisting in achieving a seal. Thus, multiple sealing paths are formed, ensuring zero fuel leakage.

[0039] Pipeline adjustment status: such as Figure 1 In sections (d) and (e), when adjusting the pipe length, keep the position and orientation of base 1 unchanged, and keep the sealing nut 9 tightened. First, loosen the three fastening nuts 5. Under the elastic force of spring 4, the bevel gear 3 moves away from the root of shaft 1-4, generating... Figure 1 The displacement shown in (d) reduces the axial force on the bevel gear surface 6-1 of the rotating tube 6 until it disappears. At this time, the compression deformation of the end face gasket 2 and the sealing head gasket 8 gradually recovers, producing a result similar to... Figure 1As shown in (d), gaps 1 and 2 allow the rotating tube 6 to produce a small axial displacement towards the origin, and the rotating tube 6 can rotate freely around its axis. During initial adjustment, the base 1 can be fixed using the base plate 1-2. A wrench can be used to turn the screw 6-5 of one of the rotating tubes 6. Due to the meshing of the bevel gear 3, the other rotating tube 6 will rotate synchronously in the opposite direction. Alternatively, both rotating tubes 6 can be turned in opposite directions simultaneously. Due to the restriction of the base retaining strip 1-8, the translation tube 7 can only translate axially and cannot rotate around its axis. At this time, due to the rotation of the rotating tube 6, the internal thread of its threaded cavity 6-4 acts on the external thread 7-1 of the translation tube, driving the translation tube 7 to translate axially away from the center of the base, thereby increasing the total length of the entire device.

[0040] The axial adjustable range of the translation tube 7 is determined by the effective length of the external thread 7-1 of the translation tube, which is generally 3 / 10 of the total length of the translation tube 7. The length of the translation tube 7 matches the length of the rotating tube 6, and can be customized according to different application scenarios. The axial adjustment is stepless, and continuous adjustment at any position is achieved by controlling the rotation angle of the rotating tube 6.

[0041] Once the desired length is achieved, stop rotating the rotating tube 6 and tighten the locking nut 5 again, causing the bevel gear 3 to return to the root of the shaft 1-4. The rotating tube 6 is then subjected to an outward axial force and moves, causing the end face gasket 2 and the sealing head gasket 8 to be compressed and sealed again, returning the entire joint to a locked and sealed state. The extreme position of the outward extension of the translation tube 7 is when the end of the external thread 7-1 of the translation tube contacts the sealing head gasket 8.

[0042] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. An adjustable-length locking and sealing pipe joint, characterized in that, include: The base (1), as the supporting body, extends axially to both ends; Two rotating tubes (6) are rotatably fitted onto the two ends of the base (1), and their inner walls are provided with internal thread sections; Two translation tubes (7) are respectively inserted into two rotating tubes (6), and their outer walls are provided with external thread sections that are fitted to the internal thread sections of the rotating tubes (6); a circumferential limiting structure is provided between the translation tube (7) and the extension of the base (1), so that the translation tube (7) can only translate along the axial direction without relative rotation. A transmission mechanism is provided on the base (1) and is used to drive the rotating tubes (6) installed at both ends of the base (1) to rotate. Fasteners, placed on the base (1), are used to apply axial preload; A sealing assembly is disposed between the rotating tube (6) and the translation tube (7), and between the rotating tube (6) and the base (1); When the fastener applies axial preload, the rotating tube (6) moves outward along the axial direction under the action of axial force, and simultaneously drives the sealing assembly to generate radial expansion, so that multiple seals are formed between the rotating tube (6) and the base (1) and between the rotating tube (6) and the translation tube (7); when the fastener releases the axial preload, it drives the rotating tube (6) to rotate through the transmission mechanism, thereby driving the translation tube (7) to translate along the axial direction, so as to realize the adjustment of the pipeline length.

2. The adjustable length locking and sealing pipe joint according to claim 1, characterized in that: The base (1) includes: The hollow connecting shaft (1-1) is a straight tubular structure of equal diameter with a hollow core. The base plate (1-2) is coaxially fixed to the outer periphery of the hollow connecting shaft (1-1) and located at the axial center. The outer periphery of the base plate (1-2) is a regular hexagon, which facilitates the use of tools to fix the base (1) during installation or maintenance. Multiple radial grooves are evenly distributed along the circumference of its outer periphery. The bottom surface of the groove is provided with a radially extending shaft (1-4). The bottom surface of the root groove of the shaft (1-4) is provided with a spring groove (1-5), and the top is provided with a shaft thread (1-6). Two small base discs (1-3) are coaxially fixed to the outer periphery of the hollow connecting shaft (1-1) and symmetrically arranged on both sides of the large base disc (1-2); a gasket groove (1-7) is provided on the side opposite to the large base disc (1-2) for installing the end face gasket (2). The base clip (1-8) is a long straight rod with its inner and outer edges being arcs concentric with the base (1). Its inner diameter is slightly larger than the inner diameter of the hollow connecting shaft (1-1), so that the base clip (1-8) does not occupy the pipeline channel. Multiple base clips (1-8) are provided on both sides of the hollow connecting shaft (1-1) along the axial extension direction, and the base clips (1-8) on both sides are symmetrically and evenly distributed, serving as the two ends of the base (1). The ends of the multiple base clips (1-8) on the same side are processed into a stepped shape to form a slightly larger end base clip (1-9). The outer end of the end base clip (1-9) is connected to a base sealing head threaded ring (1-10), which is coaxial with the hollow connecting shaft (1-1). The minor diameter of the thread of the base sealing head threaded ring (1-10) is consistent with the outer diameter of the end base clip (1-9), forming a smooth transition.

3. The adjustable length locking and sealing pipe joint according to claim 2, characterized in that: The transmission mechanism is a bevel gear transmission mechanism, including a bevel gear (3) and a spring (4). The bevel gear (3) is sleeved on the shaft (1-4), and the spring (4) is located between the bevel gear (3) and the root of the shaft (1-4), with its bottom embedded in the spring groove (1-5). The rotating tube (6) has a bevel gear surface (6-1) on one end face near the base plate (1-2), which meshes with the teeth (3-2) of the bevel gear (3); The bevel gear transmission mechanism is used to ensure that the two rotating tubes (6) rotate synchronously in opposite directions; The bevel gear (3) can float axially along the shaft (1-4). When the fastener is released, the spring (4) pushes the bevel gear (3) away from the root, so that the axial force on the rotating tube (6) disappears, while maintaining the continuous meshing between the bevel gear (3) and the bevel gear surface (6-1). The bevel gear (3) has a gear spring groove (3-1) at the small diameter end shaft. One end of the spring (4) is embedded in the spring groove (1-5), and the other end is embedded in the gear spring groove (3-1), so that both ends of the spring (4) are radially positioned to prevent the spring (4) from radially shifting during compression.

4. The adjustable length locking and sealing pipe joint according to claim 3, characterized in that: The rotating tube (6) is a hollow tubular structure, and is provided sequentially from one end near the base plate (1-2) towards the other end: The small disc cavity (6-3) has a two-stage central through hole. The small diameter section is fitted onto the hollow connecting shaft (1-1) between the large base disc (1-2) and the small base disc (1-3). The inner diameter of the large diameter section matches the outer diameter of the small base disc (1-3), allowing the rotating tube (6) to rotate around the small base disc (1-3). The axial depth of the small disc cavity (6-3) is slightly greater than the thickness of the small base disc (1-3), giving the rotating tube (6) a certain axial movement space to generate axial displacement when the fastener applies axial preload, thereby squeezing the sealing assembly. The fit between the inner wall of the large diameter section of the small disc cavity (6-3) and the outer diameter of the small base disc (1-3) simultaneously limits the maximum axial displacement of the rotating tube (6), preventing the rotating tube (6) from coming out. The end face of the small diameter section is provided with a bevel gear surface (6-1). The threaded cavity (6-4) is detachably connected at one end to the small disc cavity (6-3). The inner wall of the middle section is machined with internal threads to form the threaded cavity (6-4), which mates with the external thread (7-1) of the translation tube. The other end is provided with a base retaining strip cavity (6-6) and a sealing head cavity (6-7) to accommodate the end of the base retaining strip (1-8) and part of the sealing assembly structure. The rotating tube (6) is provided with a hexagonal screwing part (6-5) on the outside corresponding to the threaded cavity (6-4), which makes it easy to rotate the rotating tube (6) using tools such as wrenches.

5. The adjustable length locking and sealing pipe joint according to claim 4, characterized in that: The translation tube (7) is a thin-walled tubular structure with a constant inner diameter, and its outer surface is provided with: The external thread (7-1) of the translation tube is located at one end of the translation tube (7) near the base plate (1-2) and is installed in conjunction with the threaded cavity (6-4) of the rotating tube (6); The translation tube retaining groove (7-2) is an axial groove set on the outer surface of the translation tube (7). Multiple translation tube retaining grooves (7-2) are evenly distributed around the circumference of the translation tube (7). The axial length of the translation tube retaining groove (7-2) is greater than the axial length of the external thread (7-1) of the translation tube. It covers the external thread area and extends towards the end of the translation tube (7), so that the sealing recess (8-3) of the sealing head gasket (8) keeps in contact with the surface of the translation tube (7) when the translation tube (7) is in any extended position, maintaining an effective seal. The number and cross-sectional shape are consistent with the base retaining strip (1-8). It slides with the base retaining strip (1-8) along the axial direction and restricts the circumferential rotation of the translation tube (7) relative to the base (1). The external thread of the translation tube (7-1) is divided into multiple discontinuous external thread beams (7-3) along the circumferential direction by the translation tube retaining groove (7-2). The number of thread beams (7-3) is the same as the number of translation tube retaining grooves (7-2), so that the thread fit and circumferential restriction are realized in the same axial section. Pipe connector (7-4) is located at the end of the translation pipe (7) and is used to connect external pipes.

6. The adjustable length locking and sealing pipe joint according to claim 5, characterized in that: The sealing assembly includes an end face gasket (2) and a composite sealing head; The end face gasket (2) is disposed between the base small disc (1-3) and the inner end face of the small disc cavity (6-3) of the rotating tube (6). The cross section of the end face gasket (2) is convex, and the protruding part is embedded in the base gasket groove (1-7) for positioning. When under pressure, the deformation is constrained by the groove, which improves the sealing effect. The composite sealing head includes a sealing head gasket (8) and a sealing nut (9). The main body of the sealing head gasket (8) is a ring structure. Its outer ring is provided with a wedge surface (8-1). The wedge surface (8-1) is in contact with the inner wall of the sealing head cavity (6-7) of the rotating tube (6). Its inner ring is divided into a large inner ring (8-2) and a small inner ring along the axial direction. The large inner ring (8-2) is located on the side away from the base (1), and the small inner ring is located on the side close to the base (1). The stepped sealing surface (9-2) of the sealing nut (9) is in contact with the end face of the large inner ring (8-2) and the end face of the small inner ring at the same time, which axially limits the position of the sealing head gasket (8). The small inner ring is provided with multiple sealing protrusions (8-4) along the circumference. A sealing recess (8-3) is formed between adjacent sealing protrusions. The arc length of the sealing protrusion (8-4) is slightly larger than the width of the translation tube clamping groove (7-2). When it is embedded in the translation tube clamping groove (7-2), the sealing is achieved by compression. The sealing protrusion (8-4) has an axial retaining strip hole (8-5) inside for inserting the base retaining strip (1-8). The inner ring of the sealing nut (9) is provided with a sealing head thread (9-1), which is installed in conjunction with the sealing head thread ring (1-10) of the base; its outer ring is provided with a sealing head stepped sealing surface (9-2), which is in contact with the end face of the large inner ring (8-2) and the small inner ring of the sealing head gasket (8).

7. The adjustable length locking and sealing pipe joint according to claim 6, characterized in that: The far end of the sealing protrusion (8-4) near the axis is connected to the main body of the sealing head gasket (8) only through the sealing protrusion connecting part (8-6). The rest of the sealing protrusion (8-4) forms a suspended structure with the main body, so that the radial force can be transmitted to the front end of the sealing protrusion (8-4) through the sealing protrusion connecting part (8-6). The arc length of the sealing protrusion (8-4) is greater than the arc length of the locking strip hole (8-5). The middle part of the far end of the sealing protrusion (8-4) is provided with a sealing protrusion installation seam (8-7) to facilitate its fitting onto the base locking strip (1-8).

8. The adjustable length locking and sealing pipe joint according to claim 7, characterized in that: The fastener is a fastening nut (5), which is set on the shaft (1-4) and its internal thread is fitted with the shaft thread (1-6); When the fastening nut (5) is tightened, the spring (4) is compressed, the bevel gear (3) is pushed to the root of the shaft (1-4), and the rotating tube (6) is moved outward by axial force, so that the end face gasket (2) and the sealing head gasket (8) are squeezed and deformed to form a seal; When the fastening nut (5) is loosened, the spring (4) recovers its deformation, the bevel gear (3) moves away from the root of the shaft (1-4), the axial force on the rotating tube (6) disappears, the compression deformation of the end face gasket (2) and the sealing head gasket (8) is restored, and the upper length of the pipeline joint is adjusted by rotating the rotating tube (6).

9. A sealing method for an adjustable-length locking and sealing pipe joint according to any one of claims 1-8, characterized in that, include: Locking and sealing: Tightening the fastening nut (5) compresses the spring (4), pushes the bevel gear (3) to the root of the shaft (1-4), and the rotating tube (6) moves outward along the axial direction under the action of axial force, producing the following multiple sealing effects: (a) The inner end face of the small disc cavity (6-3) of the rotating tube (6) is pressed against the end face gasket (2) to achieve a seal between the rotating tube (6) and the base (1); (b) The sealing head cavity (6-7) of the rotating tube (6) presses the wedge surface (8-1) of the sealing head gasket (8) so that the wedge surface (8-1) fits tightly against the inner wall of the sealing head cavity (6-7); (c) The radial deformation of the wedge surface (8-1) under pressure causes the sealing recess (8-3) to fit tightly against the surface of the translation tube (7), while the surface of the card strip hole (8-5) away from the axis fits tightly against the base card strip (1-8); (d) The radial force is transmitted to the front end of the sealing protrusion (8-4) through the sealing protrusion connection (8-6), so that the sealing protrusion (8-4) fits tightly against the inner wall of the translation tube clamp groove (7-2); (e) After the sealing protrusion (8-4) is embedded in the translation tube clamping groove (7-2), the reaction force generated by the translation tube clamping groove (7-2) on the sealing protrusion (8-4) causes the surface of the clamping hole (8-5) near the axis to form a seal between it and the base clamping strip (1-8). Together with the seal of the surface of the clamping hole (8-5) away from the axis on the base clamping strip (1-8), it constitutes a bidirectional clamping seal on the base clamping strip (1-8). (f) The sealing nut (9) that has been tightened during assembly has its stepped sealing surface (9-2) axially defining the position of the large inner ring (8-2) and the small inner ring end face of the sealing head gasket (8), thus assisting in achieving a seal; Length adjustment: Loosen the fastening nut (5), and under the elastic force of the spring (4), the bevel gear (3) moves away from the root of the shaft (1-4), the axial force on the rotating tube (6) disappears, and the compression deformation of the end face gasket (2) and the sealing head gasket (8) is restored; rotate the rotating tube (6), and drive the two rotating tubes (6) to rotate synchronously in opposite directions through the transmission mechanism, and drive the translation tube (7) to translate along the axial direction through the threaded engagement to realize the adjustment of the pipeline length; during the adjustment process, the translation tube (7) only translates along the axial direction without rotating under the restriction of the base clamp (1-8); Reset seal: After adjusting to the target length, tighten the fastening nut (5) again. The rotating tube (6) is subjected to axial force and moves outward again. The end face gasket (2) and the sealing head gasket (8) are squeezed and deformed again, restoring the multiple sealing state in the locking seal.

10. The sealing method according to claim 9, characterized in that: During the length adjustment, when the translation tube (7) extends outward, the sealing recess (8-3) of the sealing head gasket (8) always remains in contact with the surface of the translation tube (7) to maintain an effective seal; The extreme position of the translation tube (7) extending outward is the position where the end of the external thread (7-1) of the translation tube contacts the sealing head gasket (8).

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