Tandem air cylinder tensioning mechanism and using method thereof

Abstract

The invention discloses a series air cylinder tensioning mechanism and a using method thereof. The series air cylinder tensioning mechanism can be installed on a pipeline aligning device and comprises a cylinder barrel, a first piston, a second piston, a push disc, a plurality of connecting rods, a plurality of ejector rods, a plurality of tensioning shoes and a tensioning disc. A first cavity and a second cavity are formed in the cylinder barrel. The first piston is arranged in the first cavity, the second piston is arranged in the second cavity, the second piston is fixedly connected with the first piston and the push disc, and driving media can be injected into the first cavity and the second cavity so as to drive the first piston and the second piston to move synchronously and drive the push disc to move; a plurality of guide holes are formed in the tensioning disc in the radial direction, the ejector rods penetrate through the corresponding guide holes, the connecting rods are hinged to the push disc and the ejector rods respectively, and the ejector rods can stretch out of the guide holes under the thrust action of the push disc so that the tensioning shoes can abut against the inner wall of the pipeline; according to the series air cylinder tensioning mechanism, the ovality deviation of the pipe openings of the steel pipes is effectively reduced, and the pipe openings are quickly and accurately assembled.

Description

Technical Field

[0001] The invention relates to the technical field of pipeline welding construction, and in particular to a series cylinder tensioning mechanism and a use method thereof. Background Art

[0002] As pipeline construction develops towards intelligence and digitalization and the quality of pipeline construction is increasingly valued, automatic pipeline welding technology has become the most important method of pipeline construction, and automatic pipeline welding equipment has been rapidly developed and widely promoted and applied. As the key equipment of automatic pipeline welding technology, the internal welding machine (or internal pipe jointer) that can be used for rapid assembly of pipe ends plays a vital role in realizing the on-site welding flow operation of pipeline projects.

[0003] The quality of pipeline construction welding is crucial to ensure the safe operation of the pipeline, and the ovality of the pipeline end has a great impact on the quality of the welding group, which directly affects the quality of pipeline welding construction. At present, although the ovality of long-distance pipeline pipes meets the requirements of relevant steel pipe standards when they leave the factory, there are still large deviations in the ovality of the steel pipe ends at the construction site caused by factors such as hoisting and transportation. During construction, the grading method is generally used to minimize the deviation of the two steel pipes. However, when welding steel pipes with insulation heating belts and installation position requirements, the grading method cannot be used for adjustment. This will cause difficulties in pipeline assembly and a large amount of misalignment at the joints, thereby affecting the welding quality of long-distance pipelines. Summary of the invention

[0004] In order to enrich the product categories of tensioning mechanisms, increase the selection space of tensioning and rounding methods, and improve the rounding effect, the present invention provides a series cylinder tensioning mechanism and a use method thereof.

[0005] In a first aspect, an embodiment of the present invention provides a tandem cylinder tensioning mechanism that can be installed in a pipe docking device, including a cylinder barrel, a first piston, a second piston, a push plate, a plurality of connecting rods, a plurality of push rods, a plurality of tensioning shoes and a tensioning plate;

[0006] The cylinder barrel is provided with a first cavity and a second cavity respectively;

[0007] The first piston is disposed in the first cavity, the second piston is disposed in the second cavity, and the second piston is fixedly connected to the first piston and the push plate, respectively. The first cavity and the second cavity can be respectively injected with a driving medium to drive the first piston and the second piston to move synchronously and drive the push plate to move;

[0008] The end of the push rod is fixedly connected to the corresponding expansion shoe;

[0009] A plurality of guide holes are radially arranged inside the tensioning disk, and the plurality of guide holes are evenly distributed circumferentially on the tensioning disk. The push rod is passed through the corresponding guide holes. The connecting rod is hinged to the push plate and the push rod respectively. The push rod can extend out of the guide hole under the thrust of the push plate so that the expansion shoe presses against the inner wall of the pipe.

[0010] In one or some optional embodiments, the tandem cylinder tensioning mechanism further includes a plurality of first pins and a plurality of second pins;

[0011] A plurality of guide grooves are tangentially arranged in the push plate, and the two ends of the first pin shaft are respectively inserted into two corresponding adjacent guide grooves;

[0012] A through hole is radially arranged at one end of the push rod close to the connecting rod, and the second pin shaft is inserted into the through hole;

[0013] Both ends of the connecting rod are provided with connecting holes, and the first pin shaft and the second pin shaft respectively pass through the corresponding connecting holes at both ends of the connecting rod.

[0014] In one or some optional embodiments, a plurality of grooves are radially arranged between two adjacent guide grooves;

[0015] One end of the connecting rod is located in the corresponding groove.

[0016] In one or some optional embodiments, the tandem cylinder tensioning mechanism further includes a front cylinder cover and a rear cylinder cover;

[0017] The front cylinder cover is respectively fixedly connected to the cylinder barrel and the tensioning plate;

[0018] The rear cylinder cover is fixed to one end of the cylinder barrel away from the push plate.

[0019] In one or some optional embodiments, the front cylinder head and the rear cylinder head are connected and fixed to the cylinder barrel via a first fastener.

[0020] In one or some optional embodiments, the rear cylinder cover is provided with a first communication port;

[0021] The side wall of the cylinder is provided with a second communication port;

[0022] The first communication port and the second communication port are respectively connected to the first cavity.

[0023] In one or some optional embodiments, the side wall of the cylinder is provided with a third communication port;

[0024] A fourth communication port is provided on the side of the front cylinder cover;

[0025] The third communication port and the fourth communication port are respectively connected to the second cavity.

[0026] In one or some optional embodiments, sealing rings are provided between the first piston, the second piston and the inner wall of the cylinder.

[0027] In one or some optional embodiments, grease is applied inside the guide hole.

[0028] In one or some optional embodiments, the first piston and the second piston are connected and fixed by a second fastener.

[0029] In a second aspect, an embodiment of the present invention provides a method for using the tandem cylinder tensioning mechanism according to the first aspect, comprising:

[0030] Extending the tandem cylinder tensioning mechanism into the pipeline;

[0031] At the same time, compressed air or hydraulic oil is injected into the first cavity and the second cavity, so that the first piston and the second piston push the push plate to move, drive a plurality of push rods to extend out of the guide holes, and make a plurality of expansion shoes press against the inner wall of the pipeline.

[0032] The beneficial effects of the above technical solution provided in the embodiments of the present invention include at least:

[0033] The tandem cylinder tensioning mechanism provided in the embodiment of the present invention can allow the first piston and the second piston to move simultaneously by injecting compressed air or hydraulic oil into the first cavity and the second cavity at the same time, and push the push plate to move in the direction of the tensioning plate, so that a plurality of push rods extend in the circumferential direction of the tensioning plate, and the expansion shoe presses against the inner wall of the steel pipe, thereby fixing the pipe and achieving rounding of the pipe mouth; through the synchronous movement of the first piston and the second piston, compared with the conventional cylinder tensioning mechanism, the tensioning force is greatly improved, which can effectively reduce the ovality deviation of the steel pipe mouth, improve the pipe mouth assembly effect, and achieve fast and accurate pipe mouth assembly, laying a foundation for root welding, ensuring the welding quality and construction progress, and having a high engineering promotion and application value.

[0034] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description and the accompanying drawings.

[0035] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0037] Figure 1 A front view of a tandem cylinder tensioning mechanism provided in an embodiment of the present invention;

[0038] Figure 2 A cross-sectional view of a tandem cylinder tensioning mechanism provided in an embodiment of the present invention;

[0039] Figure 3 A front view of a push plate provided in an embodiment of the present invention;

[0040] Figure 4 A cross-sectional view of a push plate provided in an embodiment of the present invention;

[0041] Figure 5 A front view of a tensioning disk provided in an embodiment of the present invention;

[0042] Figure 6 It is a cross-sectional view of a tension disk provided in an embodiment of the present invention.

[0043] In the figure:

[0044] 1. Cylinder barrel; 101. First cavity; 102. Second cavity; 103. Second connecting port; 104. Third connecting port; 2. First piston; 3. Second piston; 4. Push plate; 401. Guide groove; 402. Groove; 5. Connecting rod; 501. Connecting hole; 6. Push rod; 601. Through hole; 7. Tensioning shoe; 8. Tensioning plate; 801. Guide hole; 9. First pin shaft; 10. Second pin shaft; 11. Front cylinder head; 1101. Fourth connecting port; 12. Rear cylinder head; 1201. First connecting port; 13. First fastener; 14. Second fastener; 15. Pipeline. DETAILED DESCRIPTION

[0045] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art. In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", "far", "near", "front", "rear" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. The inventors have found that the existing tensioning mechanisms used for pipe rounding have problems such as insufficient tensioning force and inability to align pipes efficiently, which often affects the pipe joint effect and further affects the quality of pipe welding. Based on this, the present invention proposes a tandem cylinder tensioning mechanism and a method of using the same, which will be described in detail below through specific embodiments. Embodiment 1 The embodiment of the present invention provides a series cylinder tensioning mechanism, which can be installed in a pipe docking device, referring to Figure 1-Figure 6 As shown, it includes a cylinder 1, a first piston 2, a second piston 3, a push plate 4, a plurality of connecting rods 5, a plurality of push rods 6, a plurality of expansion shoes 7 and a tensioning plate 8; The cylinder 1 is provided with a first cavity 101 and a second cavity 102 respectively; The first piston 2 is disposed in the first cavity 101, the second piston 3 is disposed in the second cavity 102, and the second piston 3 is respectively fixedly connected to the first piston 2 and the push plate 4, and the first cavity 101 and the second cavity 102 can be respectively injected with a driving medium to drive the first piston 2 and the second piston 3 to move synchronously, and drive the push plate 4 to move; The end of the push rod 6 is fixedly connected to the corresponding expansion shoe 7;

[0046] A plurality of guide holes 801 are radially arranged inside the tensioning disk 8, and the plurality of guide holes 801 are evenly distributed circumferentially on the tensioning disk 8. The push rod 6 is passed through the corresponding guide holes 801. The connecting rod 5 is hinged to the push plate 4 and the push rod 6 respectively. The push rod 6 can extend out of the guide hole 801 under the thrust of the push plate 4 so that the expansion shoe 7 is against the inner wall of the pipe 15.

[0047] The tandem cylinder tensioning mechanism provided in the embodiment of the present invention can be installed in an internal welding machine (or a pipe internal aligner) for quick pipe orifice assembly, and is used for pipe orifice rounding. Specifically, when the driving medium is injected into the first cavity 101 and the second cavity 102 respectively, the driving medium injected into the two cavities will drive the first piston 2 and the second piston 3 to move synchronously, thereby driving the push plate 4 to move toward the tensioning plate 8, and then push the plurality of push rods 6 out of the guide holes 801 of the tensioning plate 8, so that the plurality of expansion shoes 7 tighten the inner wall of the pipe 15, thereby achieving the effect of pipe orifice rounding.

[0048] In the embodiment of the present invention, the driving medium injected into the first cavity 101 and the second cavity 102 may be compressed air or hydraulic oil, etc. For details, please refer to the detailed description in the prior art, which will not be repeated here.

[0049] In the embodiment of the present invention, refer to Figure 2-Figure 4 As shown, the connecting rod 5 is respectively hinged to the push plate 4 and the push rod 6. Specifically, the tandem cylinder tensioning mechanism further includes a plurality of first pins 9 and a plurality of second pins 10, a plurality of tangential guide grooves 401 are provided in the push plate 4, the two ends of the first pin 9 are respectively inserted into the corresponding two adjacent guide grooves 401 and fixed to the guide grooves 401, a radial through hole 601 is provided at one end of the push rod 6 close to the connecting rod 5, the second pin 10 is inserted into the through hole 601, both ends of the connecting rod 5 are provided with connecting holes 501, the first pin 9 and the second pin 10 respectively pass through the connecting holes 501 at both ends of the connecting rod 5, thereby realizing the hinge connection between the connecting rod 5 and the push plate 4 and the push rod 6.

[0050] In the embodiment of the present invention, refer to Figure 2-Figure 4 As shown, a plurality of grooves 402 are radially arranged between two adjacent guide grooves 401. Since the two ends of the first pin shaft 9 are respectively inserted into the corresponding two adjacent guide grooves 401, the middle of the first pin shaft 9 is located in the groove 402, one end of the connecting rod 5 is located in the corresponding groove 402, and the first pin shaft 9 passes through the connecting hole 501 at the end of the connecting rod 5, so that the connecting rod 5 can be angularly displaced relative to the first pin shaft 9; and the second pin shaft 10 is fixed to the push rod 6, and the connecting rod 5 can be angularly displaced relative to the second pin shaft 10; therefore, when the push plate 4 rises When the tightening plate 8 is pushed in the direction, the thrust of the push plate 4 is transmitted to the push rod 6 through the connecting rod 5, the angle between the push plate 4 and the connecting rod 5 gradually decreases, the angle between the connecting rod 5 and the push plate 4 gradually increases, and the push rod 6 gradually extends out of the guide hole 801, so that the expansion shoe 7 fixes and tightens the inner wall of the pipe 15. Since the specifications of several push rods 6 are consistent and evenly distributed, the specifications of several expansion shoes 7 are also consistent and evenly distributed. The pipe 15 can gradually return to a circular shape under the action of the tightening force, effectively reducing the ellipticity deviation of the steel pipe mouth, and realizing fast and accurate assembly of the pipe mouth. When the push plate 4 moves toward the rear cylinder head 12, the pulling force of the push plate 4 is transmitted to the push rod 6 through the connecting rod 5, the angle between the push plate 4 and the connecting rod 5 gradually increases, the angle between the connecting rod 5 and the push plate 4 gradually decreases, and the push rod 6 gradually retracts the guide hole 801, so that the expansion shoe 7 leaves the inner wall of the pipe 15, and releases the fixation and tightening of the inner wall of the pipe 15.

[0051] In the embodiment of the present invention, refer to Figure 2As shown, the tandem cylinder tensioning mechanism further includes a front cylinder head 11 and a rear cylinder head 12. The front cylinder head 11 is fixedly connected to the cylinder barrel 1 and the tensioning plate 8 respectively, and the rear cylinder head 12 is fixed to the end of the cylinder barrel 1 away from the push plate 4. The front cylinder head 11 and the rear cylinder head 12 are respectively matched with the cylinder barrel 1 to seal the first cavity 101 and the second cavity 102, so that the driving medium in the first cavity 101 and the second cavity 102 will not leak out. The front cylinder head 11 and the rear cylinder head 12 are connected and fixed to the cylinder barrel 1 by a first fastener 13, and the first fastener 13 can be a bolt, etc., which is not specifically limited here.

[0052] In the embodiment of the present invention, refer to Figure 2 As shown, the first piston 2 and the second piston 3 are coaxially locked and connected by a second fastener 14, and the second fastener 14 is arranged at the center of the first piston 2 and the second piston 3, so that the first piston 2 and the second piston 3 can apply a more uniform thrust to the push plate 4, making it easier to push the push plate 4 to move. The second fastener 14 can be a nut, etc., and is not specifically limited here.

[0053] In a specific embodiment, the second piston 3 is fixedly connected to the push plate 4, and the fixed connection method includes but is not limited to bolt connection. For details, please refer to the detailed records in the prior art, which will not be repeated here.

[0054] In a specific embodiment, the push rod 6 is fixedly connected to the expansion shoe 7, and the fixing connection method includes but is not limited to bolt connection. For details, please refer to the detailed records in the prior art, which will not be repeated here.

[0055] In a specific embodiment, a sealing ring (not shown in the figure) is arranged between the first piston 2, the second piston 3 and the inner wall of the cylinder 1, which facilitates the movement of the first piston 2 and the second piston 3 while ensuring the sealing of the first cavity 101 and the second cavity 102. Since the second piston 3 is connected to the push plate 4, a sealing ring is also arranged between the second piston 3 and the front cylinder cover 11 to prevent the driving medium in the second cavity 102 from overflowing.

[0056] In a specific embodiment, referring to Figure 2 and Figure 6As shown, the rear cylinder cover 12 is provided with a first connecting port 1201, and the side wall of the cylinder barrel 1 is provided with a second connecting port 103, the first connecting port 1201 and the second connecting port 103 are respectively connected to the first cavity 101, and the first piston 2 is located between the first connecting port 1201 and the second connecting port 103; the first connecting port 1201 and the second connecting port 103 can be connected to the driving medium supply device through a pipeline; when the driving medium fills the first cavity 101 and continues to be injected into the first cavity 101 from the first connecting port 1201, the first piston 2 drives the second piston 3 to move in the direction of the push plate 4, and the driving medium flows out from the second connecting port 103, driving the push plate 4 to move in the direction of the tensioning plate 8, so that the push rod 6 extends out of the guide hole 801 and the tensioning shoe 7 tightens the inner wall of the pipe 15. If the push rod 6 is to be retracted and the expansion shoe 7 is to be separated from the inner wall of the pipe 15 , a driving medium can be injected into the first cavity 101 from the second connecting port 103 , so that the first piston 2 drives the second piston 3 to move toward the rear cylinder head 12 , thereby driving the push plate 4 to move toward the rear cylinder head 12 and retracting the push rod 6 into the guide hole 801 .

[0057] In a specific embodiment, referring to Figure 2 and Figure 6 As shown, the side wall of the cylinder 1 is provided with a third connecting port 104, and the front cylinder head 11 is provided with a fourth connecting port 1101. The third connecting port 104 and the fourth connecting port 1101 are respectively connected to the second cavity 102 for heat exchange, and the second piston 3 is located between the third connecting port 104 and the fourth connecting port 1101; the third connecting port 104 and the fourth connecting port 1101 can be connected to the driving medium supply device through a pipeline; when the driving medium fills the second cavity 102 and continues to be injected into the second cavity 102 from the third connecting port 104, the second piston 3 drives the first piston 2 to move in the direction of the push plate 4, and the driving medium flows out from the fourth connecting port 1101, driving the push plate 4 to move in the direction of the tensioning plate 8, so that the push rod 6 extends out of the guide hole 801 and the tensioning shoe 7 tightens the inner wall of the pipe 15. If the push rod 6 is to be retracted and the expansion shoe 7 is to be separated from the inner wall of the pipe 15, a driving medium can be injected into the second cavity 102 from the fourth connecting port 1101, so that the second piston 3 drives the first piston 2 to move toward the rear cylinder head 12, thereby driving the push plate 4 to move toward the rear cylinder head 12 and retracting the push rod 6 into the guide hole 801.

[0058] In the embodiment of the present invention, by injecting the driving medium from the first connecting port 1201 and the third connecting port 104 to the first cavity 101 and the second cavity 102 at the same time, that is, driving the first piston 2 and the second piston 3 at the same time, the first piston 2 and the second piston 3 will move synchronously in the direction of the tensioning plate 8, pushing the push plate 4 to move in the direction of the tensioning plate 8, so that the plurality of expansion shoes 7 are expanded along the circumferential direction of the tensioning plate 8, tightening the inner wall of the pipe 15, thereby fixing the pipe 15 and completing the pipe mouth rounding. By coaxially connecting and using the first piston 2 and the second piston 3 at the same time, compared with the conventional cylinder tensioning mechanism, the tensioning force is greatly improved. The inventor has found through comparative verification that the tensioning force can be increased by about 90%, thereby effectively reducing the ovality deviation of the steel pipe mouth, improving the efficiency and effect of the pipe mouth rounding, and achieving accurate pipe 15.

[0059] In the embodiment of the present invention, if the push rod 6 is to be retracted into the guide hole 801 and the expansion shoe 7 is to be separated from the inner wall of the pipe 15, a driving medium can be injected into the first cavity 101 and the second cavity 102 from the second connecting port 103 and the fourth connecting port 1101 at the same time, so that the driving medium flows out from the first connecting port 1201 and the third connecting port 104, driving the first piston 2 and the second piston 3 to move toward the rear cylinder head 12, and driving the push plate 4 to move toward the rear cylinder head 12, thereby retracting the push rod 6 and separating the expansion shoe 7 from the inner wall of the pipe 15.

[0060] In the embodiment of the present invention, grease may be applied to the guide hole 801 to reduce the friction between the guide hole 801 and the push rod 6 , thereby minimizing the resistance of the guide hole 801 to the push rod 6 , so that the push rod 6 can smoothly extend and slide in the guide hole 801 .

[0061] In the embodiment of the present invention, the specific process of using the series cylinder tensioning mechanism to calibrate the pipe opening of the pipe 15 may include:

[0062] The driving medium is injected into the first cavity 101 and the second cavity 102 simultaneously through the first connecting port 1201 and the third connecting port 104, driving the first piston 2 and the second piston 3 to move synchronously in the direction of the tensioning plate 8, and driving the push plate 4 to move in the direction of the tensioning plate 8, the connecting rod 5 transmits the thrust of the push plate 4 to the push rod 6, so that the push rod 6 extends out of the guide hole 801 and the expansion shoe 7 circumferentially tightens the inner wall of the pipe 15, the first piston 2 and the second piston 3 are continuously driven by force, so that the pipe mouth of the pipe 15 gradually restores a circular shape under the action of the tightening force;

[0063] After the calibration is completed, a driving medium is injected into the first cavity 101 and the second cavity 102 through the second connecting port 103 and the fourth connecting port 1101 to drive the first piston 2 and the second piston 3 to move synchronously in the direction of the rear cylinder head 12, and drive the push plate 4 to move in the direction of the rear cylinder head 12, and the connecting rod 5 transmits the pulling force of the push plate 4 to the push rod 6, so that the push rod 6 retracts the guide hole 801, thereby releasing the tightening force of the expansion shoe 7 on the inner wall of the pipe 15.

[0064] The tandem cylinder tensioning mechanism provided in the embodiment of the present invention can allow the first piston 2 and the second piston 3 to move simultaneously by injecting compressed air or hydraulic oil into the first cavity 101 and the second cavity 102 at the same time, and push the push plate 4 to move in the direction of the tensioning plate 8, so that a plurality of push rods 6 extend in the circumferential direction of the tensioning plate 8, and the expansion shoe 7 presses against the inner wall of the steel pipe, thereby fixing the pipe 15 and realizing the rounding of the pipe mouth; through the synchronous movement of the first piston 2 and the second piston 3, compared with the conventional cylinder tensioning mechanism, the tensioning force is greatly improved, which can effectively reduce the ovality deviation of the steel pipe mouth, improve the pipe mouth assembly effect, and realize fast and accurate pipe mouth assembly, laying a foundation for root welding, ensuring the welding quality and construction progress, and having a high engineering promotion and application value.

[0065] Embodiment 2

[0066] Based on the same inventive concept, an embodiment of the present invention further provides a method for using the tandem cylinder tensioning mechanism described in Embodiment 1, comprising:

[0067] S101: Extend the tandem cylinder tensioning mechanism into the pipe 15;

[0068] S102: Compressed air or hydraulic oil is injected into the first cavity 101 and the second cavity 102 at the same time, so that the first piston 2 and the second piston 3 push the push plate 4 to move, driving the plurality of push rods 6 to extend out of the guide holes 801, so that the plurality of expansion shoes 7 are against the inner wall of the pipe 15.

[0069] In the embodiment of the present invention, the method of using the tandem cylinder tensioning mechanism corresponds to the tandem cylinder tensioning mechanism described in Example 1. Its specific implementation process can refer to the specific process of using the tandem cylinder tensioning mechanism in Example 1 to achieve pipe orifice rounding, and the repeated parts will not be repeated.

[0070] Obviously, various changes and modifications may be made to the present invention by those skilled in the art without departing from the spirit and scope of the present invention. The present disclosure is not limited to the precise structure described above and shown in the accompanying drawings, and various changes and modifications may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims. Thus, if these changes and modifications of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these changes and modifications.

Claims

1. A series cylinder tensioning mechanism, which can be installed on a pipe docking device, characterized in that: It includes a cylinder, a first piston, a second piston, a push plate, a plurality of connecting rods, a plurality of push rods, a plurality of expansion shoes and a tensioning plate; The cylinder barrel is provided with a first cavity and a second cavity respectively; The first piston is disposed in the first cavity, the second piston is disposed in the second cavity, and the second piston is fixedly connected to the first piston and the push plate, respectively. The first cavity and the second cavity can be respectively injected with a driving medium to drive the first piston and the second piston to move synchronously and drive the push plate to move; The end of the push rod is fixedly connected to the corresponding expansion shoe; A plurality of guide holes are radially arranged inside the tensioning disk, and the plurality of guide holes are evenly distributed circumferentially on the tensioning disk. The push rod is passed through the corresponding guide holes. The connecting rod is hinged to the push plate and the push rod respectively. The push rod can extend out of the guide hole under the thrust of the push plate so that the expansion shoe presses against the inner wall of the pipe.

2. The tandem cylinder tensioning mechanism according to claim 1, characterized in that: The tandem cylinder tensioning mechanism also includes a plurality of first pins and a plurality of second pins; A plurality of guide grooves are tangentially arranged in the push plate, and the two ends of the first pin shaft are respectively inserted into two corresponding adjacent guide grooves; A through hole is radially arranged at one end of the push rod close to the connecting rod, and the second pin shaft is inserted into the through hole; Both ends of the connecting rod are provided with connecting holes, and the first pin shaft and the second pin shaft respectively pass through the corresponding connecting holes at both ends of the connecting rod.

3. The tandem cylinder tensioning mechanism according to claim 2, characterized in that: A plurality of grooves are radially arranged between two adjacent guide grooves; One end of the connecting rod is located in the corresponding groove.

4. The tandem cylinder tensioning mechanism according to claim 1, characterized in that: The tandem cylinder tensioning mechanism also includes a front cylinder cover and a rear cylinder cover; The front cylinder cover is respectively fixedly connected to the cylinder barrel and the tensioning plate; The rear cylinder cover is fixed to one end of the cylinder barrel away from the push plate.

5. The tandem cylinder tensioning mechanism according to claim 4, characterized in that: The front cylinder head and the rear cylinder head are connected and fixed to the cylinder barrel via a first fastener.

6. The tandem cylinder tensioning mechanism according to claim 4, characterized in that: The rear cylinder cover is provided with a first communication port; The side wall of the cylinder is provided with a second communication port; The first communication port and the second communication port are respectively connected to the first cavity.

7. The tandem cylinder tensioning mechanism according to claim 4, characterized in that: The side wall of the cylinder is provided with a third communication port; A fourth communication port is provided on the side of the front cylinder cover; The third communication port and the fourth communication port are respectively connected to the second cavity.

8. The tandem cylinder tensioning mechanism according to claim 1, characterized in that: A sealing ring is arranged between the first piston, the second piston and the inner wall of the cylinder.

9. The tandem cylinder tensioning mechanism according to claim 1, characterized in that: The guide hole is coated with grease.

10. The tandem cylinder tensioning mechanism according to claim 1, characterized in that: The first piston and the second piston are connected and fixed by a second fastener.

11. A method for using the tandem cylinder tensioning mechanism according to any one of claims 1 to 10, characterized in that: include: Extending the tandem cylinder tensioning mechanism into the pipeline; At the same time, compressed air or hydraulic oil is injected into the first cavity and the second cavity, so that the first piston and the second piston push the push plate to move, drive a plurality of push rods to extend out of the guide holes, and make a plurality of expansion shoes press against the inner wall of the pipeline.

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