A telescopic mechanism, system and method of a mouthpiece for small and medium pipe diameters

Abstract

This invention discloses a telescopic mechanism, system, and method for an internal alignment device for small and medium diameter pipes. The mechanism includes a hydraulic cylinder, a male mold, a female mold, and a universal coupling. The male mold is fitted inside the female mold. The female mold connects to the rear support of the internal alignment device. The male mold connects to the front support of the internal alignment device. One end of the universal coupling connects to the front support of the internal alignment device, and the other end connects to the piston rod of the hydraulic cylinder. When the piston rod of the hydraulic cylinder extends outward, it pushes the universal coupling to move the male mold away from the female mold. The system includes at least one displacement sensor, a front support of the internal alignment device, a rear support of the internal alignment device, a controller, and a telescopic mechanism. This mechanism, system, and method can flexibly switch the telescopic state of the telescopic mechanism according to the conditions of the pipeline, allowing the internal alignment device to smoothly pass through bends in small and medium diameter pipes.

Description

Technical Field

[0001] This invention relates to the field of pipe alignment technology, and particularly to a telescopic mechanism, system and method for an internal alignment device for small and medium diameter pipes. Background Technology

[0002] With the rapid development of China's oil pipeline construction, the proportion of pipeline construction in mountainous areas is increasing. Due to the special terrain of mountainous areas, the internal alignment tools need to have strong bending capabilities. Especially for internal alignment tools with small and medium diameter pipes, the small internal space of the pipe strictly limits the external dimensions of the internal alignment tools.

[0003] Currently, the length of internal connectors for small and medium-sized pipelines is insufficient to directly pass through bends with a curvature radius of 6 times the pipe diameter. Even with a split design and a spring-loaded flexible connection in the middle, excessive curvature can cause spring failure and even damage to the inner wall of the pipe. Therefore, it is urgent to solve the problem of bending for internal connectors in small and medium-diameter pipes. Summary of the Invention

[0004] In view of the above problems, the present invention is proposed to provide a telescopic mechanism, system and method for a small-diameter pipe fitting that overcomes or at least partially solves the above problems.

[0005] In a first aspect, embodiments of the present invention provide a telescopic mechanism for a small-diameter pipe fitting, comprising:

[0006] Hydraulic cylinders, male molds, female molds, and universal joints;

[0007] The male mold is fitted inside the female mold; the female mold is used to connect with the rear support of the inner mouth-aligning device; the male mold is used to connect with the front support of the inner mouth-aligning device.

[0008] One end of the universal joint is used to connect to the front bracket of the inner alignment device, and the other end is connected to the piston rod of the hydraulic cylinder, so that when the piston rod of the hydraulic cylinder extends outward, it pushes the universal joint to move the male mold away from the female mold.

[0009] In one embodiment, the telescopic mechanism of the small-diameter pipe fitting described above further includes: a sliding shaft and a guide key;

[0010] The master mold has a first through hole, and the sliding shaft is slidably disposed in the first through hole;

[0011] The hydraulic cylinder is connected to the universal joint via the sliding shaft.

[0012] In one embodiment, the telescopic mechanism of the small-diameter pipe fitting described above has a guide groove on the inner wall of the first through hole and a keyway on the outer wall of the sliding shaft; the guide key is disposed in the keyway and can slide along the guide groove.

[0013] In one embodiment, the telescopic mechanism of the aforementioned small-diameter pipe fitting, wherein the hydraulic cylinder and the universal joint are connected via the sliding shaft, specifically includes:

[0014] The inner wall of the sliding shaft is provided with a second through hole, and the piston rod of the hydraulic cylinder is connected to the inlet of the second through hole;

[0015] The sliding shaft has a first stop and a first hole at its end face. The sliding shaft is connected to the rear end face of the universal joint through the first hole and the universal joint is axially limited by the first stop.

[0016] In one embodiment, in the telescopic mechanism of the above-mentioned small-diameter pipe fitting, the inner diameter of the first through hole in the female mold is the same as the outer diameter of the sliding shaft.

[0017] In one embodiment, the telescopic mechanism of the small-diameter pipe fitting device further includes: a hydraulic cylinder fixing seat; the hydraulic cylinder fixing seat is L-shaped, the hydraulic cylinder is disposed at the horizontal end of the hydraulic cylinder fixing seat, and the female mold is connected to the vertical end of the hydraulic fixing seat.

[0018] In one embodiment, in the telescopic mechanism of the above-mentioned small-diameter pipe fitting device, the vertical end of the hydraulic cylinder fixing seat is provided with a second hole and a second stop. The hydraulic cylinder fixing seat is connected to the female mold through the second hole and the female mold is axially limited by the second stop.

[0019] In one embodiment, the telescopic mechanism of the above-mentioned small-diameter pipe fitting device has a hydraulic cylinder with a protruding step; a limiting groove is provided at the horizontal end of the hydraulic cylinder fixing seat, and the protruding step is disposed in the limiting groove to axially limit the hydraulic cylinder.

[0020] In one embodiment, the telescopic mechanism of the aforementioned small-diameter pipe fitting device has a female mold with a flared outer contour to match the outer contour of the male mold.

[0021] Secondly, embodiments of the present invention provide a control system for the telescopic mechanism of a small-diameter pipe fitting, comprising:

[0022] At least one displacement sensor, a front support for the inner connector, a rear support for the inner connector, a controller, and a telescopic mechanism for the small-diameter inner connector as described above.

[0023] In the telescopic mechanism of the small-diameter pipe alignment device, the male mold is connected to the front support of the inner alignment device, and the female mold is connected to the rear support of the inner alignment device.

[0024] The at least one displacement sensor is disposed on the front bracket of the inner alignment device;

[0025] The controller is electrically connected to at least one displacement sensor and the hydraulic cylinder in the telescopic mechanism, respectively.

[0026] The controller is used to determine whether the inner alignment device is in a bend or a straight section of the pipeline based on the displacement signal received from at least one displacement sensor. If it is determined to be in a bend, a first control signal is sent to the hydraulic cylinder to control the piston of the hydraulic cylinder to extend, pushing the universal joint to drive the front frame and rear frame of the inner alignment device to pass through the bend in sequence, separating the male mold and the female mold. If it is determined that the inner alignment device has moved from the bend to the straight section, a second control signal is sent to the hydraulic cylinder to control the piston rod of the hydraulic cylinder to pull back the universal joint until the male mold and the female mold abut together.

[0027] Thirdly, embodiments of the present invention provide a method for controlling the telescopic mechanism of a small-diameter internal connector, the method being implemented using the aforementioned telescopic mechanism of a small-diameter internal connector, the method comprising the following steps:

[0028] Based on the displacement signal received from at least one displacement sensor, it is determined whether the inner fitting is in a bend or a straight section of the pipeline.

[0029] When the judgment result is a curved section, the piston rod of the control hydraulic cylinder extends, pushing the universal joint to drive the front frame and rear frame of the inner aligner to pass through the curve in sequence, and the male mold and female mold separate; when the judgment result is that the inner aligner moves from the curved section to the straight section, the piston rod of the control hydraulic cylinder pulls back the universal joint, and the male mold and female mold abut together.

[0030] The beneficial effects of the above-described technical solutions provided in the embodiments of the present invention include at least the following:

[0031] The telescopic mechanism of the small-diameter pipe alignment device provided in this embodiment of the invention is disposed between the front support and the rear support of the pipe alignment device, so that the pipe alignment device can adopt a split structure. When the pipe alignment device travels in the bend, the telescopic mechanism is in the extended state. Relative to the rear frame of the pipe alignment device, the front frame of the pipe alignment device can swing freely under the constraint of the universal joint. The front and rear parts of the pipe alignment device can adaptively adjust their states according to the curvature of the bend to ensure that the pipe alignment device can pass smoothly through the bend of small-diameter pipes.

[0032] Furthermore, during the assembly of the inner connector, the telescopic mechanism is in the retracted state, so that the front and rear parts of the inner connector can form an effective rigid body, which can smoothly complete the pipe end assembly. Therefore, the telescopic mechanism can flexibly switch between telescopic states according to the pipeline conditions, so that the inner connector can adapt to the travel of straight and curved sections of small and medium diameter pipes, as well as the pipe alignment requirements.

[0033] Furthermore, the telescopic mechanism control system of the small-diameter pipe fitting provided in this embodiment of the invention uses intelligent control to deploy displacement sensors at the front end of the pipe fitting to monitor the inner wall of the pipe in real time, so as to realize the automatic switching of rigidity and flexibility of the telescopic mechanism of the small-diameter pipe fitting in the pipe, avoid manual operation, effectively save human resources, and efficiently enable the pipe fitting to pass smoothly through bends.

[0034] Furthermore, the telescopic mechanism control method for small-diameter pipe fittings provided in this embodiment of the invention determines the position of the telescopic mechanism of the small-diameter pipe fitting in the pipe by real-time monitoring of the inner wall of the pipe, so as to achieve the purpose of automatically switching the rigidity and flexibility of the telescopic mechanism. This method enables the telescopic mechanism to be applied autonomously and flexibly to small-diameter pipe bending scenarios and pipe fitting scenarios of the internal fitting.

[0035] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings.

[0036] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0037] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0038] Figure 1 This is a schematic diagram of the retracted state structure of the telescopic mechanism of the small-diameter pipe fitting in an embodiment of the present invention;

[0039] Figure 2 This is a schematic diagram of the extended state structure of the telescopic mechanism of the small-diameter pipe fitting in an embodiment of the present invention;

[0040] Figure 3 This is a schematic diagram of the sliding shaft structure in an embodiment of the present invention;

[0041] Figure 4 This is a schematic diagram of the hydraulic cylinder mounting base structure in an embodiment of the present invention;

[0042] Figure 5 This is a schematic diagram of the master mold structure in an embodiment of the present invention;

[0043] Figure 6 This is a schematic diagram of the common mold structure in an embodiment of the present invention;

[0044] Figure 7 This is a schematic diagram of the control method for the telescopic mechanism of the small-diameter pipe fitting in an embodiment of the present invention;

[0045] Explanation of reference numerals in the attached figures:

[0046] 1-Hydraulic cylinder; 2-Hydraulic cylinder mounting base; 3-Sliding shaft; 4-Guide key; 5-Female mold; 6-Universal coupling; 7-Male mold; 11-Drive oil chamber; 12-Retracting oil chamber; 21-Limit groove; 22-Second hole; 23-Second stop; 24-Third hole; 31-Keyway; 32-Second through hole; 33-First hole; 34-First stop; 51-First through hole; 52-Guide groove; 53-First connecting hole; 71-Second connecting hole. Detailed Implementation

[0047] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0048] The inventors of this invention discovered that even with a spring-type flexible connection in the middle section, internal couplings with a split design cannot directly pass through bends with a radius of curvature of 6 times the pipe diameter. Therefore, the problem of bending for internal couplings with small and medium diameter pipes urgently needs to be solved.

[0049] To address the aforementioned issues, embodiments of the present invention provide a telescopic mechanism, system, and method for a small-diameter pipe fitting.

[0050] First, the telescopic mechanism of the small-diameter pipe fitting provided in the embodiments of the present invention will be described in detail, referring to... Figure 1 As shown, the telescopic mechanism may specifically include: a hydraulic cylinder 1, a male mold 7, a female mold 5, and a universal coupling 6; wherein:

[0051] The aforementioned male mold 7 is fitted inside the female mold 5; the female mold 5 is used to connect with the rear support of the inner alignment device; the male mold 7 is used to connect with the front support of the inner alignment device; one end of the universal coupling 6 is used to connect with the front support of the inner alignment device, and the other end is connected with the piston rod of the hydraulic cylinder 1, so that when the piston rod of the hydraulic cylinder 1 extends outward, it pushes the universal coupling 6 to drive the male mold 7 to move away from the end of the female mold 5.

[0052] The telescopic mechanism of the small-diameter pipe fitting provided in this embodiment of the invention is disposed between the front and rear supports of the pipe fitting, allowing the pipe fitting to adopt a split structure. When the pipe fitting travels in a bend, the telescopic mechanism is in the extended state. Relative to the rear frame of the pipe fitting, the front frame can swing freely under the constraint of the universal joint 6. The front and rear parts of the fitting can adaptively adjust their states according to the curvature of the bend to ensure that the pipe fitting can smoothly pass through bends of small-diameter pipes. Furthermore, when the pipe fitting is being assembled, the telescopic mechanism is in the retracted state, so that the front and rear parts of the pipe fitting can form an effective rigid body, which can smoothly complete the pipe fitting. Therefore, the telescopic mechanism can flexibly switch between telescopic states according to the conditions of the pipeline, so that the pipe fitting can adapt to the travel of the pipe fitting in straight and curved sections of small-diameter pipes, as well as the pipe fitting requirements.

[0053] In one embodiment, the telescopic mechanism of the small-diameter pipe fitting described above further includes: a sliding shaft 3 and a guide key 4;

[0054] Reference Figure 2 As shown, the female mold 5 has a first through hole 51, and the sliding shaft 3 is slidably disposed in the first through hole 51; the hydraulic cylinder 1 and the universal joint 6 are connected through the sliding shaft 3.

[0055] In one embodiment, a guide groove 52 is provided on the inner wall of the first through hole 51, and a keyway 31 is provided on the outer wall of the sliding shaft 3, as detailed below. Figure 3 As shown; the guide key 4 is set in the keyway 31 and can slide along the guide groove 52. This structure allows the guide key 4 to sequentially drive the sliding shaft 3 to generate relative displacement with the female mold 5 within the length range set by the guide groove 52. At the same time, the sliding shaft 3 will not rotate relative to the female mold 5. Due to the transmission of motion, when the sliding shaft 3 is pushed or pulled back by the piston rod of the hydraulic cylinder 1 and generates relative displacement with the female mold 5, the male mold 7 and the female mold 5 also generate corresponding relative displacement.

[0056] In one embodiment, the hydraulic cylinder 1 and the universal joint 6 are connected via the aforementioned sliding shaft 3, specifically in the following manner:

[0057] The inner wall of the sliding shaft 3 is provided with a second through hole 32, and the piston rod of the hydraulic cylinder 1 is connected to the inlet of the second through hole 32; the end face of the end of the sliding shaft 3 is provided with a first stop 34 and a first hole 33, the sliding shaft 3 is connected to the rear end face of the universal joint 6 through the first hole 33, and the universal joint 6 is axially limited by the first stop 34.

[0058] In one implementation, for example, an internal thread can be provided at the inlet of the second through hole 32 of the piston rod, through which the piston rod of the hydraulic cylinder 1 is connected to the sliding shaft 3.

[0059] In one embodiment, the first hole 33 and the universal coupling 6 can be connected by threads.

[0060] In one embodiment, the inner diameter of the first through hole 51 in the aforementioned female mold 5 is the same as the outer diameter of the sliding shaft 3.

[0061] In one embodiment, the telescopic mechanism of the aforementioned small-diameter pipe fitting further includes: a hydraulic cylinder 1 fixing seat; in a specific implementation, the hydraulic cylinder 1 fixing seat can be L-shaped, as shown in the reference. Figure 4 As shown, the hydraulic cylinder 1 is located at the horizontal end of the hydraulic cylinder 1 fixed seat, and the female mold 5 is connected to the vertical end of the hydraulic steel fixed seat.

[0062] In one embodiment, a third hole 24 is provided at the bottom of the horizontal end of the hydraulic cylinder 1 fixing seat, and the hydraulic cylinder 1 is fixed to the hydraulic cylinder 1 fixing seat through the third hole 24.

[0063] In one embodiment, the vertical end of the fixed seat of the hydraulic cylinder 1 is provided with a second hole 22 and a second stop 23. The hydraulic fixed seat is connected to the female mold 5 through the second hole 22 and the female mold 5 is axially limited by the second stop 23. This structure allows the outer surface of the male mold 7 to fit against the inner surface of the female mold 5 to form an effective rigid body when the entire telescopic mechanism is in the retracted state, so that the inner fitting device can smoothly perform pipe mouth assembly.

[0064] In one embodiment, the hydraulic cylinder 1 has a protruding step; a limiting groove 21 is provided at the horizontal end of the fixed seat of the hydraulic cylinder 1, and the protruding step is disposed in the limiting groove 21 to limit the hydraulic cylinder 1 axially.

[0065] In one embodiment, the outer contour of the female mold 5 is trumpet-shaped, as shown in the reference. Figure 5 As shown, it is designed to match the outer contour of the male mold 7.

[0066] In one embodiment, the end of the female mold 5 away from the flared opening is connected to the fixed seat of the hydraulic cylinder 1; in a specific implementation, the end of the female mold 5 away from the flared opening is provided with a threaded hole, and the female mold 5 is connected to the fixed seat of the hydraulic cylinder 1 through the threaded hole.

[0067] In one embodiment, the end of the female mold 5 away from the flared opening is used to connect with the rear frame of the inner aligner; in a specific implementation, the end of the female mold 5 away from the flared opening may be provided with a plurality of first connecting holes 53, through which the female mold 5 is connected to the rear frame of the inner aligner.

[0068] In one embodiment, the end of the male mold 7 furthest from the female mold 5 is used to connect to the front frame of the inner alignment device; in a specific implementation, the end of the male mold 7 furthest from the female mold 5 is provided with a plurality of second connecting holes 71, the positions of which can be referred to... Figure 6 As shown, the male mold 7 is connected to the front frame of the inner connector through the multiple second connection holes 71.

[0069] In one embodiment, multiple holes may be formed on the outer contour of the female mold 5 to reduce the weight of the female mold, as detailed in the following figure. Figure 5 As shown.

[0070] In one embodiment, multiple holes can be formed on the outer contour of the male mold 7 to reduce the weight of the male mold, as detailed in the following figure. Figure 6 As shown.

[0071] This invention also provides a control system for the telescopic mechanism of a small-diameter pipe fitting, the system specifically including:

[0072] At least one displacement sensor, a front support for the inner connector, a rear support for the inner connector, a controller, and a telescopic mechanism for the small-diameter inner connector as described above.

[0073] In the telescopic mechanism of the aforementioned small-diameter pipe alignment device, the male mold 7 is connected to the front support of the inner alignment device, and the female mold 5 is connected to the rear support of the inner alignment device; at least one displacement sensor is installed on the front support of the inner alignment device; the controller is electrically connected to at least one displacement sensor and the hydraulic cylinder 1 in the telescopic mechanism.

[0074] The controller is used to determine whether the inner alignment device is in a bend or a straight section of the pipeline based on the displacement signal received from at least one displacement sensor. If it is determined to be in a bend, a first control signal is sent to the hydraulic cylinder 1 to control the piston of the hydraulic cylinder 1 to extend and push the universal joint 6 to drive the front frame and rear frame of the inner alignment device to pass through the bend in sequence, and the male mold 7 and the female mold 5 separate. If it is determined that the inner alignment device has moved from the bend to the straight section, a second control signal is sent to the hydraulic cylinder 1 to control the piston rod of the hydraulic cylinder 1 to pull back the universal joint 6 until the male mold 7 and the female mold 5 abut together.

[0075] The telescopic mechanism control system for small-diameter pipe fittings provided in this invention uses intelligent control to deploy displacement sensors at the front end of the pipe fitting to monitor the inner wall of the pipe in real time. This enables the automatic switching of the rigidity and flexibility of the telescopic mechanism of the small-diameter pipe fitting in the pipe, effectively saving manpower and efficiently enabling the pipe fitting to pass smoothly through bends.

[0076] This invention also provides a method for controlling the telescopic mechanism of a small-diameter pipe fitting, which is implemented using the aforementioned telescopic mechanism of a small-diameter pipe fitting. Figure 7As shown, the method may specifically include the following steps:

[0077] S71, Receive displacement signal from at least one displacement sensor;

[0078] S72. Based on the received displacement signal, determine whether the inner alignment device is in a bend or a straight section of the pipeline.

[0079] S73. When the judgment result is a curved section, the piston rod of the hydraulic cylinder 1 is extended to push the universal joint 6 to drive the front frame and rear frame of the inner aligner to pass through the curve in sequence, and the male mold 7 and female mold 5 are separated.

[0080] S74. When the judgment result is that the inner alignment device moves from the curved section to the straight section, the piston rod of the hydraulic cylinder 1 is controlled to pull back the universal joint 6, and the male mold 7 and the female mold 5 abut together.

[0081] The telescopic mechanism control method for small-diameter pipe fittings provided in this invention monitors the inner wall of the pipe in real time to determine the position of the telescopic mechanism in the pipe, thereby achieving the purpose of automatically switching between rigidity and flexibility of the telescopic mechanism. This method enables the telescopic mechanism to be applied autonomously and flexibly to small-diameter pipe bending scenarios and pipe fitting scenarios of the internal fitting.

[0082] The following example illustrates the working process of the telescopic mechanism, control system, and method of the small-diameter pipe fitting provided in the embodiments of the present invention.

[0083] See Figure 1 As shown, this example illustrates the telescopic mechanism of the pipe fitting device for small and medium diameter pipes. The hydraulic cylinder 1 has two oil chambers: a drive oil chamber 11 and a retraction oil chamber 12. Both the drive oil chamber 11 and the retraction oil chamber 12 have oil inlets. When oil enters the oil inlet of the drive oil chamber 11, the drive oil chamber 11 drives the piston rod to extend. When oil enters the oil inlet of the retraction oil chamber 12, the retraction oil chamber 12 drives the piston rod to retract.

[0084] Hydraulic cylinder 1 piston rod extension process: After oil enters the oil inlet of the drive oil chamber 11, the piston rod extends, pushing the sliding shaft 3 forward along the first through hole 51 of the female mold 5. Because the first through hole 51 is equipped with a guide key 4, the sliding shaft 3 will not rotate relative to the female mold 5. At the same time, the sliding shaft 3 pushes the universal joint 6 forward. Since one end of the universal joint 6 is connected to the front frame of the inner alignment device, and the front frame is connected to the male mold 7, the outer surface of the male mold 7 separates from the inner surface of the female mold 5 and begins to move away from the female mold 5. At this time, relative to the rear frame of the inner alignment device, the front frame of the inner alignment device can swing freely under the constraint of the universal joint 6. The front and rear parts of the alignment device can adaptively adjust their states according to the curvature of the bend to ensure that the inner alignment device can smoothly pass through the bend with a curvature radius of 6 times the pipe diameter. For details on the extension state of the telescopic mechanism of the inner alignment device for small and medium diameter pipes, please refer to [reference needed]. Figure 2 As shown.

[0085] Hydraulic cylinder 1 piston rod retraction process: After oil enters the oil inlet of the retractable oil chamber 12, the piston rod retracts. The piston rod pulls the sliding shaft 3 to slide backward along the first through hole 51 of the female mold 5. Because the first through hole 51 is equipped with a guide key 4, the sliding shaft 3 will not rotate relative to the female mold 5. At the same time, the sliding shaft 3 pulls the universal joint 6 to slide backward. Since one end of the universal joint 6 is connected to the front frame of the inner fitting device, and the front frame is connected to the male mold 7, the outer surface of the male mold 7 moves towards the end close to the female mold 5 until the outer surface of the male mold 7 is pressed against the inner surface of the female mold 5, so that the front and rear parts of the inner fitting device form an effective rigid body, which facilitates the subsequent assembly work of the inner fitting device. For the specific retraction state of the telescopic mechanism of the small and medium diameter inner fitting device, please refer to Figure 1 As shown.

[0086] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A telescopic mechanism for a small-to-medium diameter pipe fitting, characterized in that, include: Hydraulic cylinders, male molds, female molds, and universal joints; The male mold is fitted inside the female mold; The female mold is used to connect with the rear support of the inner mouth-aligner; the male mold is used to connect with the front support of the inner mouth-aligner. One end of the universal joint is used to connect to the front bracket of the inner alignment device, and the other end is connected to the piston rod of the hydraulic cylinder, so that when the piston rod of the hydraulic cylinder extends outward, it pushes the universal joint to move the male mold away from the female mold.

2. The telescopic mechanism of the small-diameter pipe fitting as described in claim 1, characterized in that, Also includes: Sliding shaft and guide key; The master mold has a first through hole, and the sliding shaft is slidably disposed in the first through hole; The hydraulic cylinder is connected to the universal joint via the sliding shaft.

3. The telescopic mechanism of a small-diameter pipe fitting as described in claim 2, characterized in that, A guide groove is provided on the inner wall of the first through hole, and a keyway is provided on the outer wall of the sliding shaft; the guide key is disposed in the keyway and can slide along the guide groove.

4. The telescopic mechanism of the small-diameter pipe fitting as described in claim 2, characterized in that, The hydraulic cylinder and the universal joint are connected via the sliding shaft, specifically including: The inner wall of the sliding shaft is provided with a second through hole, and the piston rod of the hydraulic cylinder is connected to the inlet of the second through hole; The sliding shaft has a first stop and a first hole at its end face. The sliding shaft is connected to the rear end face of the universal joint through the first hole and the universal joint is axially limited by the first stop.

5. The telescopic mechanism of the small-diameter pipe fitting as described in claim 2, characterized in that, The inner diameter of the first through hole in the master mold is the same as the outer diameter of the sliding shaft.

6. The telescopic mechanism of the small-diameter pipe fitting as described in any one of claims 1-5, characterized in that, Also includes: Hydraulic cylinder mounting base; the hydraulic cylinder mounting base is L-shaped, the hydraulic cylinder is disposed at the horizontal end of the hydraulic cylinder mounting base, and the female mold is connected to the vertical end of the hydraulic cylinder mounting base.

7. The telescopic mechanism of the small-diameter pipe fitting as described in claim 6, characterized in that, The vertical end of the hydraulic cylinder fixing seat is provided with a second hole and a second stop. The hydraulic cylinder fixing seat is connected to the female mold through the second hole and the female mold is axially limited by the second stop.

8. The telescopic mechanism of the small-diameter pipe fitting as described in claim 6, characterized in that, The hydraulic cylinder has a protruding step; a limiting groove is provided at the horizontal end of the hydraulic cylinder fixing seat, and the protruding step is disposed in the limiting groove to limit the hydraulic cylinder axially.

9. The telescopic mechanism of the small-diameter pipe fitting as described in any one of claims 1-5, characterized in that, The outer contour of the female mold is trumpet-shaped to match the outer contour of the male mold.

10. A control system for the telescopic mechanism of a small-diameter pipe fitting, characterized in that, include: At least one displacement sensor, a front support for the inner connector, a rear support for the inner connector, a controller, and a telescopic mechanism for the small-diameter inner connector as described in any one of claims 1-9; In the telescopic mechanism of the small-diameter pipe alignment device, the male mold is connected to the front support of the inner alignment device, and the female mold is connected to the rear support of the inner alignment device. The at least one displacement sensor is disposed on the front bracket of the inner alignment device; The controller is electrically connected to at least one displacement sensor and the hydraulic cylinder in the telescopic mechanism, respectively. The controller is used to determine whether the inner alignment device is in a bend or a straight section of the pipeline based on the displacement signal received from at least one displacement sensor. If it is determined to be in a bend, a first control signal is sent to the hydraulic cylinder to control the piston of the hydraulic cylinder to extend, pushing the universal joint to drive the front frame and rear frame of the inner alignment device to pass through the bend in sequence, separating the male mold and the female mold. If it is determined that the inner alignment device has moved from the bend to the straight section, a second control signal is sent to the hydraulic cylinder to control the piston rod of the hydraulic cylinder to pull back the universal joint until the male mold and the female mold abut together.

11. A method for controlling the telescopic mechanism of a small-diameter pipe fitting, the method being implemented using the telescopic mechanism of a small-diameter pipe fitting as described in any one of claims 1-9, characterized in that, The method includes the following steps: Based on the displacement signal received from at least one displacement sensor, it is determined whether the inner fitting is in a bend or a straight section of the pipeline. When the judgment result is a curved section, the piston rod of the control hydraulic cylinder extends, pushing the universal joint to drive the front frame and rear frame of the inner aligner to pass through the curve in sequence, and the male mold and female mold separate; when the judgment result is that the inner aligner moves from the curved section to the straight section, the piston rod of the control hydraulic cylinder pulls back the universal joint, and the male mold and female mold abut together.

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