A multi-joint pipeline robot

Abstract

The present application relates to a multi-joint pipeline robot, including a body, a running part and a shooting unit, wherein the body is provided with a mounting slot, and a running part is installed in each mounting slot; the running part includes a plurality of buffer racks, and the buffer rack includes two buffer plates, and the buffer plates are rotatably connected to the body; the buffer rack also includes an elastic member connected between the two buffer plates, and also includes a supporting wheel pair installed on each buffer plate, and the supporting wheel pair includes a running wheel, and the running wheel is rotatably connected to the buffer plate; the running part also includes a guide mechanism and a crawler, and the guide mechanism includes a guide wheel rotatably connected to the body, and the crawler includes a chain and a plurality of pads, and the plurality of pads are connected end to end to form a closed annular structure, and the annular structure formed by the pads is coated on the guide wheel and the running wheel, and the chain is fixed on the pad, and the running part is connected with a driving mechanism. The present application enables the pipeline robot to conveniently pass through obstacles in the raised part of the pipeline.

Description

Technical Field

[0001] The present application relates to the technical field of pipeline robots, and in particular to a multi-joint pipeline robot. Background Art

[0002] A pipeline robot is an integrated mechanical, electrical and instrumentation system that can automatically walk along the inside or outside of a small pipeline, carry one or more sensors and operating machinery, and perform a series of pipeline operations under remote control by staff or automatic computer control.

[0003] At present, the patent document with the authorization announcement number CN206191162U discloses a pipeline robot, whose main technical solution is that it includes two symmetrically arranged bracket units, a control unit is connected between the two bracket units, the bracket unit and the control unit are connected through a universal joint, a walking unit is connected to the bracket unit, the bracket unit includes an electric push rod and three brackets, the electric push rod is provided with three evenly distributed adjustment nuts, the three brackets are connected to the electric push rod through the adjustment nuts, and the three brackets are arranged in an isosceles triangle; the walking unit includes a motor box, two walking wheels, a motor and two bevel gears. This pipeline robot can detect whether there are cracks inside a straight pipeline.

[0004] With respect to the above-mentioned related technologies, the inventor believes that the support unit of the above-mentioned pipeline robot is prone to get stuck when encountering obstacles in the raised parts inside the pipeline, thereby hindering the detection work, and therefore it needs to be improved. Summary of the invention

[0005] In order to enable the pipeline robot to easily pass through obstacles at raised locations within the pipeline, the present application provides a multi-joint pipeline robot.

[0006] The multi-joint pipeline robot provided in this application adopts the following technical solution:

[0007] A multi-joint pipeline robot comprises a body, a running part and a shooting unit, wherein the body is provided with no less than three installation slots, and a running part is installed in each installation slot; the running part comprises a plurality of buffer frames, each buffer frame comprises two buffer plates, and the buffer plates are rotatably connected to the body; the buffer frame also comprises an elastic member connected between the two buffer plates, and also comprises a supporting wheel pair installed on each buffer plate, the supporting wheel pair comprises a running wheel, and the running wheel is rotatably connected to the buffer plate; the running part also comprises a guide mechanism and a crawler track, the guide mechanism comprises a guide wheel rotatably connected to the body, the crawler track comprises a chain and a plurality of pads, the plurality of pads are connected end to end to form a closed ring structure, adjacent pads are hinged to each other, the ring structure formed by the pads covers the guide wheel and the running wheel, the chain is fixed on the pad, and the running part is connected to a driving mechanism.

[0008] By adopting the above technical solution, the machine body is placed in the pipeline, and the driving mechanism drives the pad to rotate around the guide wheel and the running wheel, so that the machine body can move in the pipeline. When the machine body encounters a protruding obstacle on the inner wall of the pipeline during its movement, the protruding obstacle can push the pad, so that the pad applies pressure to the running wheel, and then push the buffer plate to rotate. The rotation of the buffer plate can compress the elastic part, and at the same time the relative position of the running wheel and the machine body changes, so that the shape of the annular structure surrounded by multiple pads can be changed to make way for the protruding obstacle, so that the machine body can smoothly cross the protruding obstacle in the pipeline.

[0009] Optionally, the driving mechanism includes a driving shaft rotatably supported on the machine body, and also includes a driving sprocket fixed on the driving shaft, the driving sprocket is meshed with the chain, and the driving shaft is connected to a power component.

[0010] By adopting the above technical solution, after the drive shaft rotates under the action of the power assembly, it can drive the drive sprocket to rotate. Since the drive sprocket is meshed with the chain, the drive sprocket can drive the pad to move along the annular path.

[0011] Optionally, the driving mechanism also includes a driving bevel gear fixed on the driving shaft, a transmission shaft rotatably supported inside the machine body, and a driving bevel gear fixed on the transmission shaft, the transmission bevel gear meshing with the driving bevel gear; the transmission shaft is connected to a power mechanism.

[0012] By adopting the above technical solution, the power mechanism drives the transmission shaft to rotate, which can drive the transmission bevel gear to rotate. Since the transmission bevel gear is meshed with the driving bevel gear, and the driving bevel gear is fixed on the driving shaft, the rotation of the transmission shaft can drive the driving shaft to rotate.

[0013] Optionally, the driving mechanism further comprises a driving member installed in the body, the driving member is connected to the driving bevel gear and can drive the driving bevel gear to rotate, a connecting bevel gear is fixed on the transmission shaft, and the driving bevel gear is meshed with the connecting bevel gear.

[0014] By adopting the above technical solution, the driving member drives the active bevel gear to rotate, and then drives the connecting bevel gear to rotate. Since the connecting bevel gear is fixed on the transmission shaft, the driving member can be started to drive the transmission shaft to rotate.

[0015] Optionally, a connecting sleeve is fixedly provided on the buffer plate, and a connecting shaft is rotatably connected to the connecting sleeve. The elastic member is a buffer hydraulic cylinder, and the buffer hydraulic cylinder is connected between two connecting shafts on the same buffer frame, and the cylinder barrel of the buffer hydraulic cylinder is rotatably connected to one connecting shaft, and the end of the piston rod of the buffer hydraulic cylinder is rotatably connected to another connecting shaft.

[0016] By adopting the above technical solution, the buffer plate can drive the buffer hydraulic cylinder to expand and contract after rotating, so that the buffer hydraulic cylinder absorbs or releases elastic potential energy, thereby achieving a shock-absorbing effect.

[0017] Optionally, the shooting unit includes a mounting arm rotatably supported on the body, a mounting bracket fixed to the mounting arm, and a camera rotatably connected to the mounting bracket, and a driving device for driving the mounting arm to rotate is provided on the body.

[0018] By adopting the above technical solution, the mounting arm rotates and the camera is connected to the mounting frame so that the camera can be rotated in two dimensions, and the viewing angle is wider when the camera is shooting.

[0019] Optionally, a driving shaft is fixedly provided on the mounting arm, and the driving shaft is rotatably supported on the machine body. A power part is fixedly provided on the machine body, and the power part is connected to a power gear and can drive the power gear to rotate. A transmission gear is fixed on the driving shaft, and the power gear is meshed with the transmission gear.

[0020] By adopting the above technical solution, the power member drives the power gear to rotate, which can drive the transmission gear to rotate. Since the transmission gear is fixed on the driving shaft, the rotation of the transmission gear can drive the driving shaft to rotate, thereby achieving the purpose of driving the installation arm to rotate.

[0021] Optionally, a mounting shaft is rotatably supported on the mounting frame, the camera is fixed on the mounting shaft, the mounting shaft is connected to a driving assembly, the driving assembly includes a driving motor, a driving gear and a reversing gear, the driving motor is fixed on the mounting frame, the driving gear is fixed on the output shaft of the driving motor, the reversing gear is fixed on the mounting shaft, and the driving gear and the reversing gear are meshed with each other.

[0022] By adopting the above technical solution, the driving motor drives the active gear to rotate, which can drive the reversing gear to rotate, thereby driving the installation shaft to rotate, thereby achieving the purpose of driving the camera to rotate, allowing the camera to shoot at a wider viewing angle.

[0023] In summary, the present application includes at least one of the following beneficial technical effects:

[0024] 1. The machine body is placed in the pipeline, and the driving mechanism drives the pad to rotate around the guide wheel and the running wheel, so that the machine body can move in the pipeline. When the machine body encounters a raised obstacle on the inner wall of the pipeline during its movement, the raised obstacle can push the pad, so that the pad exerts pressure on the running wheel, and then pushes the buffer plate to rotate. The rotation of the buffer plate can compress the elastic member, and at the same time, the relative position of the running wheel and the machine body changes, so that the shape of the annular structure surrounded by multiple pads can be changed to make way for the raised obstacle, so that the machine body can smoothly pass over the raised obstacle in the pipeline;

[0025] 2. After the drive shaft rotates under the action of the power assembly, it can drive the drive sprocket to rotate. Since the drive sprocket is engaged with the chain, the drive sprocket can drive the pad to move along the circular path. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the overall structure of an embodiment of the present application.

[0027] Figure 2 This is a cross-sectional view of the machine body to show the running gear and drive mechanism.

[0028] Figure 3 yes Figure 2 Partial structural diagram at A in the middle, in order to illustrate the structure of the buffer rack.

[0029] Figure 4 yes Figure 2 Partial structural diagram at B in the figure to illustrate the driving mechanism.

[0030] Description of reference numerals: 1, machine body; 11, mounting groove; 12, mounting sleeve; 121, limit bearing; 2, running part; 21, buffer frame; 211, hinge shaft; 212, buffer plate; 213, positioning sleeve; 214, connecting sleeve; 215, connecting shaft; 216, buffer hydraulic cylinder; 217, supporting sleeve; 218, supporting wheel pair; 2181, supporting shaft; 2182, running wheel; 22, guide mechanism; 221, guide shaft; 222, guide wheel; 23, crawler; 231, chain; 232, pad; 3 , shooting unit; 31, mounting arm; 311, driving shaft; 312, transmission gear; 32, power member; 321, power gear; 33, mounting frame; 331, mounting shaft; 332, accommodating chamber; 34, camera; 35, driving assembly; 351, driving motor; 352, driving gear; 353, reversing gear; 4, driving mechanism; 41, driving shaft; 42, driving sprocket; 43, driving bevel gear; 44, transmission shaft; 45, transmission bevel gear; 46, driving member; 47, driving bevel gear; 48, connecting bevel gear. DETAILED DESCRIPTION

[0031] The following is combined with Figure 1-4 This application is described in further detail.

[0032] The present application embodiment discloses a multi-joint pipeline robot. Figure 1 The multi-joint pipeline robot includes a body 1, a running part 2 and a shooting unit 3, and a driving mechanism 4 for driving the running part 2, wherein the body 1 is a cylindrical cavity shell structure, and no less than three mounting grooves 11 are arranged on the side wall of the body 1. In the present embodiment, three mounting grooves 11 are provided, and the mounting grooves 11 are long strip grooves with rectangular side walls. The mounting grooves 11 are arranged along the axial direction of the body 1 and penetrate to the two end faces of the body 1. The mounting grooves 11 are evenly arranged at equal angles along the circumferential direction of the outer wall of the body 1.

[0033] Reference Figure 2 and Figure 3, the number of running parts 2 is the same as the number of mounting slots 11. In the present embodiment, three running parts 2 are provided, and each mounting slot 11 is provided with one running part 2 mentioned above. Each running part 2 includes a plurality of buffer racks 21. In the present embodiment, each running part 2 is provided with two buffer racks 21; each buffer rack 21 includes two mutually parallel hinge shafts 211 fixed on the side walls of the mounting slot 11, and also includes two buffer plates 212. The two buffer plates 212 are symmetrically arranged about a plane passing through the middle of the two hinge shafts 211. A positioning sleeve 213 is fixed on each buffer plate 212. The positioning sleeve 213 is a cylindrical cylinder with openings at both ends. The two positioning sleeves 213 are respectively sleeved on the two hinge shafts 211, so that the two buffer plates 212 are rotatably connected to the two hinge shafts 211.

[0034] Reference Figure 2 and Figure 3 A connecting sleeve 214 is also fixedly provided on the buffer plate 212. The connecting sleeve 214 is a cylinder with openings at both ends. The axis of the connecting sleeve 214 is parallel to the hinge shaft 211. A connecting shaft 215 is passed through each connecting sleeve 214. The connecting shaft 215 is rotatably connected to the connecting sleeve 214. The buffer frame 21 also includes a buffer hydraulic cylinder 216 connected between the two connecting shafts 215. The cylinder barrel of the buffer hydraulic cylinder 216 is rotatably connected to one connecting shaft 215, and the end of the piston rod of the buffer hydraulic cylinder 216 is rotatably connected to the other connecting shaft 215. When the buffer plate 212 rotates around the hinge shaft 211, it can drive the buffer hydraulic cylinder 216 to expand and contract, so that the buffer hydraulic cylinder 216 has the effect of buffering vibration.

[0035] Reference Figure 2 and Figure 3 A support sleeve 217 is fixedly provided on each buffer plate 212. The support sleeve 217 is also a cylinder with openings at both ends. The axis of the support sleeve 217 is parallel to the axis of the hinge shaft 211. The connecting sleeve 214 and the support sleeve 217 on the same buffer plate 212 are respectively arranged on both sides of the plane determined by the axes of the two hinge shafts 211 on the same buffer frame 21, and the support sleeve 217 is closer to the opening of the mounting groove 11 than the connecting sleeve 214.

[0036] Reference Figure 2 and Figure 3The buffer frame 21 also includes a support wheel pair 218 installed on each support sleeve 217, and the support wheel pair 218 includes a support shaft 2181 inserted into the support sleeve 217, and the support shaft 2181 is rotatably connected to the support sleeve 217. Both ends of the support shaft 2181 respectively pass through the openings at both ends of the support sleeve 217. The support wheel pair 218 also includes a running wheel 2182 coaxially fixed at both ends of the support shaft 2181. The running wheel 2182 is a cylindrical structure, which is used to support the body 1.

[0037] Reference Figure 2 and Figure 3 The running part 2 also includes a plurality of guide mechanisms 22. In the present embodiment, two guide mechanisms 22 are provided. Each guide mechanism 22 includes a guide shaft 221 fixed on the side wall of the mounting groove 11. The guide shaft 221 is arranged parallel to the hinge shaft 211. The guide mechanism 22 also includes a guide wheel 222 rotatably connected to the guide shaft 221. The guide wheel 222 is a cylindrical structure. The running part 2 also includes a track 23. The track 23 includes a chain 231 and a plurality of pads 232. The pads 232 are rectangular structures. The plurality of pads 232 are connected end to end to form a closed ring structure. The two edges of adjacent pads 232 are hinged to each other. The ring structure formed by the pads 232 is covered on the guide wheel 222 and the running wheel 2182 and is in a taut state. The chain 231 is fixed to the edge of the pad 232 and forms a closed loop along the path surrounded by the pad 232.

[0038] Reference Figure 2 and Figure 3 The driving mechanism 4 includes a driving shaft 41 rotatably supported in each mounting groove 11, and the driving shaft 41 is arranged parallel to the hinge shaft 211. The driving mechanism 4 also includes a driving sprocket 42 coaxially fixed on the driving shaft 41, and the driving sprocket 42 is arranged inside the annular path surrounded by the pad 232, and the driving sprocket 42 and the chain 231 are meshed with each other. By driving the driving shaft 41 to rotate, the driving sprocket 42 can be rotated. Since the driving sprocket 42 is meshed with the chain 231, the chain 231 can drive multiple pads 2 The circular path formed by the plurality of pads 232 is rotated to place the machine body 1 in the pipeline so that the pad 232 is against the inner wall of the pipeline. The rotation of the pad 232 can drive the machine body 1 to move in the pipeline. If there is a raised obstacle on the inner wall of the pipeline, the raised part can generate a thrust on the pad 232, thereby pushing the buffer plate 212 to rotate around the hinge shaft 211, so that the relative position of the running wheel 2182 and the machine body 1 changes, and then the shape of the annular structure surrounded by multiple pads 232 changes, so as to facilitate the machine body 1 to cross the obstacle in the pipeline.

[0039] Reference Figure 3 and Figure 4The end of the driving shaft 41 passes through the side wall of the mounting groove 11 and extends into the interior of the body 1. The driving mechanism 4 also includes a driving bevel gear 43 coaxially fixed on the portion of the driving shaft 41 located in the body 1, and also includes a transmission shaft 44 rotatably supported inside the body 1. The transmission shaft 44 is arranged along the radial direction of the cross section of the body 1. In the present embodiment, three transmission shafts 44 are arranged, and the three transmission shafts 44 are arranged at equal intervals. Each transmission shaft 44 is close to a driving bevel gear 43. The driving mechanism 4 also includes a transmission bevel gear 45 coaxially fixed on each transmission shaft 44. The three transmission bevel gears 45 are meshed with the three driving bevel gears 43 respectively.

[0040] Reference Figure 2 and Figure 4 The driving mechanism 4 also includes a driving member 46 installed in the body 1. In this embodiment, the driving member 46 is an electric motor, which is fixed on the inner wall of the body 1. The driving mechanism 4 also includes an active bevel gear 47 coaxially fixed on the output shaft of the motor. The active bevel gear 47 is coaxially arranged with the body 1. In addition, the driving mechanism 4 also includes a connecting bevel gear 48 coaxially fixed on each transmission shaft 44. The three connecting bevel gears 48 are meshed with the active bevel gear 47 at the same time. Starting the motor can drive the active bevel gear 47 to rotate, and then drive the connecting bevel gear 48 to rotate. Through the transmission of the transmission bevel gear 45 and the driving bevel gear 43, each driving shaft 41 is driven to rotate, so as to achieve the purpose of making the driving sprocket 42 drive the pad 232 to move around the annular path.

[0041] Reference Figure 1 The shooting unit 3 includes a mounting arm 31, which is a cylindrical rod-shaped structure. The mounting arm 31 is coaxially arranged with the body 1. A mounting sleeve 12 is fixedly arranged on one end surface of the body 1. The mounting sleeve 12 is coaxially fixed with the body 1. An opening is provided at the end of the mounting sleeve 12 away from the body 1. The mounting arm 31 is inserted into the mounting sleeve 12, and a gap is provided between the mounting arm 31 and the mounting sleeve 12. A limit bearing 121 is provided in the gap between the mounting sleeve 12 and the mounting arm 31. In this embodiment, the limit bearing 121 adopts a cylindrical roller bearing, the inner ring of the limit bearing 121 is fixed on the mounting arm 31, and the outer ring of the limit bearing 121 is fixed on the inner wall of the mounting sleeve 12, so that the mounting arm 31 is rotatably supported in the mounting sleeve 12.

[0042] Reference Figure 1 and Figure 2A driving shaft 311 is fixedly provided at the end of the mounting arm 31 close to the body 1. The driving shaft 311 is coaxially arranged with the mounting arm 31. The driving shaft 311 passes through the end of the body 1 and extends into the interior of the body 1. A power member 32 is fixedly provided on the inner wall of the body 1. In the present embodiment, the power member 32 is an electric motor. A power gear 321 is fixed on the output shaft of the motor. A transmission gear 312 is coaxially fixed on the driving shaft 311. The power gear 321 is meshed with the transmission gear 312. Starting the motor drives the power gear 321 to rotate, which can drive the transmission gear 312 to rotate. The rotation of the transmission gear 312 can drive the driving shaft 311 to rotate, thereby achieving the purpose of driving the mounting arm 31 to rotate.

[0043] Reference Figure 1 A U-shaped mounting bracket 33 is fixedly provided at the end of the mounting arm 31 away from the body 1, and a mounting shaft 331 is rotatably supported in the mounting bracket 33. A camera 34 for photographing the inside of the pipeline is fixed on the mounting shaft 331. In addition, a accommodating chamber 332 is provided on the mounting bracket 33, and a driving assembly 35 is connected to the mounting shaft 331. The driving assembly 35 includes a driving motor 351, a driving gear 352 and a reversing gear 353. The driving motor 351 is fixed in the accommodating chamber 332, and the driving gear 352 is coaxially fixed on the output shaft of the driving motor 351. The reversing gear 353 is coaxially fixed on the mounting shaft 331. The driving gear 352 and the reversing gear 353 are meshed with each other. After the output shaft of the driving motor 351 rotates, the driving gear 352 can be driven to rotate, and then the reversing gear 353 is driven to rotate, thereby driving the mounting shaft 331 to rotate, so as to achieve the purpose of changing the shooting direction of the camera 34.

[0044] The implementation principle of a multi-joint pipeline robot in an embodiment of the present application is: placing the body 1 in the pipeline, starting the motor of the driving mechanism 4, which can drive the multiple pads 232 of the running part 2 to move in a circular path, and the pads 232 are against the inner wall of the body 1 to drive the body 1 to move along the pipeline to be inspected. When the body 1 encounters a protruding obstacle in the pipeline, the protruding obstacle can push the pad 232, so that the pad 232 generates pressure on the running wheel 2182 to push the buffer plate 212 to rotate around the hinge shaft 211, so that the relative position of the running wheel 2182 and the body 1 changes, and then the shape of the annular structure surrounded by the multiple pads 232 can be changed to make way for the protruding obstacle, so that the body 1 can smoothly cross the protruding obstacle in the pipeline.

[0045] The embodiments of this specific implementation method are all preferred embodiments of the present application, and are not intended to limit the protection scope of the present application. Therefore, all equivalent changes made based on the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A multi-joint pipeline robot, characterized in that: It comprises a body (1), a running unit (2) and a shooting unit (3), wherein the body (1) is provided with no less than three mounting slots (11), and each mounting slot (11) is provided with one of the running units (2); The running part (2) comprises a plurality of buffer frames (21), each buffer frame (21) comprises two buffer plates (212), and the buffer plates (212) are rotatably connected to the machine body (1); the buffer frame (21) also comprises an elastic member connected between the two buffer plates (212), and also comprises a supporting wheel pair (218) mounted on each buffer plate (212), the supporting wheel pair (218) comprises a running wheel (2182), and the running wheel (2182) is rotatably connected to the buffer plate (212); The running part (2) further comprises a guide mechanism (22) and a crawler track (23), the guide mechanism (22) comprising a guide wheel (222) rotatably connected to the machine body (1), the crawler track (23) comprising a chain (231) and a plurality of pads (232), the plurality of pads (232) being connected end to end to form a closed annular structure, adjacent pads (232) being hinged to each other, the annular structure formed by the pads (232) covering the guide wheel (222) and the running wheel (2182), the chain (231) being fixed to the pads (232), and the running part (2) being connected to a driving mechanism (4); The driving mechanism (4) comprises a driving shaft (41) rotatably supported on the machine body (1), and also comprises a driving sprocket (42) fixed on the driving shaft (41), the driving sprocket (42) being meshed with the chain (231), and the driving shaft (41) is connected to a power assembly; The driving mechanism (4) further comprises a driving bevel gear (43) fixed on the driving shaft (41), a transmission shaft (44) rotatably supported inside the machine body (1), and a driving bevel gear (45) fixed on the transmission shaft (44), wherein the driving bevel gear (45) meshes with the driving bevel gear (43); the transmission shaft (44) is connected to a power mechanism; The driving mechanism (4) further comprises a driving member (46) installed in the machine body (1), the driving member (46) being connected to a driving bevel gear (47) and being capable of driving the driving bevel gear (47) to rotate, a connecting bevel gear (48) being fixed on the transmission shaft (44), and the driving bevel gear (47) being meshed with the connecting bevel gear (48); The photographing unit (3) comprises a mounting arm (31) rotatably supported on the body (1), a mounting frame (33) fixed on the mounting arm (31), and a camera (34) rotatably connected to the mounting frame (33); the body (1) is provided with a driving device for driving the mounting arm (31) to rotate; A driving shaft (311) is fixedly arranged on the mounting arm (31), and the driving shaft (311) is rotatably supported on the machine body (1). A power piece (32) is fixedly arranged on the machine body (1), and the power piece (32) is connected to a power gear (321) and can drive the power gear (321) to rotate. A transmission gear (312) is fixedly arranged on the driving shaft (311), and the power gear (321) is meshed with the transmission gear (312); The mounting frame (33) is rotatably supported with a mounting shaft (331), the camera (34) is fixed on the mounting shaft (331), the mounting shaft (331) is connected with a driving assembly (35), the driving assembly (35) comprises a driving motor (351), a driving gear (352) and a reversing gear (353), the driving motor (351) is fixed on the mounting frame (33), the driving gear (352) is fixed on the output shaft of the driving motor (351), the reversing gear (353) is fixed on the mounting shaft (331), and the driving gear (352) and the reversing gear (353) are meshed with each other.

2. A multi-joint pipeline robot according to claim 1, characterized in that: A connecting sleeve (214) is fixedly provided on the buffer plate (212), and a connecting shaft (215) is rotatably connected to the connecting sleeve (214). The elastic member is a buffer hydraulic cylinder (216), and the buffer hydraulic cylinder (216) is connected between two connecting shafts (215) on the same buffer frame (21), and the cylinder barrel of the buffer hydraulic cylinder (216) is rotatably connected to one connecting shaft (215), and the end of the piston rod of the buffer hydraulic cylinder (216) is rotatably connected to the other connecting shaft (215).

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