CN114084805A

CN114084805A - Derrick plays to rise anti-drop protection mechanism for oil-well rig

Info

Publication number: CN114084805A
Application number: CN202111306847.9A
Authority: CN
Inventors: 苟灵生
Original assignee: Xijing University
Current assignee: Xijing University
Priority date: 2021-11-05
Filing date: 2021-11-05
Publication date: 2022-02-25

Abstract

The invention relates to a derrick lifting anti-drop protection mechanism for an oil drilling machine, which comprises a frame body, wherein a traveling block is arranged in the frame body, two sides of the traveling block are fixedly connected with traction rings, a winch is arranged on one side of the frame body, traction ropes are wound on winch drums, the tail ends of the traction ropes are tied on the two traction rings, a crown block is arranged right below the traveling block, the bottom of the traveling block is fixedly connected with a suspension ring, a plurality of suspension ropes are tied on the suspension ring, the tail ends of the suspension ropes are fixedly connected with four corners of the top of the crown block, the side walls on two sides of the crown block are fixedly connected with connecting blocks, movable grooves matched with the connecting blocks are formed in the side walls on two sides of the frame body, the tail ends of the connecting blocks penetrate through the movable grooves and are fixedly connected with mounting blocks, speed measuring sensors are mounted on the mounting blocks, and a first brake mechanism and a second brake mechanism are respectively arranged above and below the mounting blocks. The invention has the characteristics of reasonable structural design, timely braking, various braking means, capability of effectively preventing the derrick from being damaged due to the falling of a rope during lifting and the like.

Description

Derrick plays to rise anti-drop protection mechanism for oil-well rig

Technical Field

The invention relates to the technical field of oil exploration, in particular to a derrick lifting anti-drop protection mechanism for an oil drilling machine.

Background

In the field of oil exploration, an oil drilling machine is used for driving a drilling tool to crush rock and drill downwards so as to drill a well hole with a specified depth, and an oil extraction machine or a gas extraction machine can obtain oil or natural gas. The derrick is used for placing crown block, hanging traveling block, hook, hanging ring and elevator, and taking off and storing drilling rod, oil pipe and sucker rod. The oil rig can not be installed and operated without leaving the derrick.

The derrick of the petroleum drilling machine on the market at present lacks anti-drop protection measures due to structural design, when a rope drops in the lifting process, the rope cannot be braked in time, so that related drilling machine components such as a crown block fall rapidly, the related components are damaged due to severe impact between the components and the ground under the action of gravity, normal work of the derrick is influenced, and safety accidents are caused, so that the derrick lifting anti-drop protection mechanism for the petroleum drilling machine is urgently needed to be invented.

Disclosure of Invention

The invention solves the technical problem that the derrick of the petroleum drilling machine in the prior art is short of anti-drop protection measures, and the derrick lifting anti-drop protection mechanism for the petroleum drilling machine is provided, so that the defect that braking cannot be performed in time when a rope drops in the lifting process is overcome. The derrick lifting anti-drop protection mechanism for the petroleum drilling machine has the characteristics of reasonable structural design, timely braking, various braking means, capability of effectively preventing damage to the derrick due to the fact that a rope drops during lifting and the like.

In order to achieve the purpose, the invention provides the following technical scheme: a derrick lifting anti-drop protection mechanism for an oil drilling machine comprises a frame body, wherein a traveling block is arranged in the frame body, traction rings are fixedly connected to the side walls of the two sides of the traveling block, a pair of wheel carriers are fixedly connected to the top of the frame body, wheel shafts are fixedly connected between the wheel carriers, guide wheels are movably connected to the shaft bodies of the wheel shafts, rope grooves are formed in the surfaces of the guide wheels, a winch is arranged on one side of the frame body, traction ropes are wound on a roller of the winch and penetrate through the rope grooves in the surfaces of the guide wheels, the tail end of each traction rope is divided into two strands and tied on the two traction rings respectively, a crown block is arranged under the traveling block, a suspension ring is fixedly connected to the bottom of the crown block, a plurality of suspension ropes are tied on the suspension ring, the tail end of each suspension rope is fixedly connected to four corners of the top of the crown block, and connecting blocks are fixedly connected to the side walls of the two sides of the crown block, the utility model discloses a speed sensor, including support body, connecting block, installation piece, speed sensor, the both sides lateral wall of support body all seted up with connecting block matched with movable groove, the end of connecting block passes movable groove and fixedly connected with installation piece, the installation piece is located outside the support body, just install speed sensor on the installation piece, the top and the below of overhead traveling crane are provided with first arrestment mechanism and second arrestment mechanism respectively.

Preferably, the top fixedly connected with fixed block of tourist car, the equal fixedly connected with connecting rod in both sides of fixed block, the spacing pipe of terminal fixedly connected with of connecting rod, spacing pipe box is established on the haulage rope.

Preferably, first brake mechanism includes first cylinder, first cylinder is installed at the both sides inner wall of overhead traveling crane, and its output shaft runs through the lateral wall and the fixedly connected with braking plate of overhead traveling crane, just through control line electric connection between first cylinder and the speed sensor.

Preferably, second arrestment mechanism includes the braking frame, braking frame fixed connection is in the bottom of overhead traveling crane, and the opening has all been seted up to its both sides lateral wall, open-ended inner wall fixedly connected with shaft, the axle body swing joint of shaft has the braked wheel, the braked wheel laminating is at the inner wall of support body, the bottom inner wall fixedly connected with riser of braking frame, the second cylinder is all installed to the both sides of riser, the terminal fixedly connected with brake pads of output shaft of second cylinder, just pass through control line electric connection between second cylinder and the tacho sensor, the below of braking frame is provided with buffer gear.

Preferably, the brake block is arc-shaped, a layer of non-slip mat is arranged on the surface of one side, close to the brake wheel, of the brake block, a layer of non-slip mat is also arranged on the surface of one side, close to the inner wall of the frame body, of the brake block, the non-slip mat is of a rubber pad structure, and herringbone non-slip lines are engraved on the surface of the non-slip mat.

Preferably, buffer gear includes a pair of buffer cylinder, buffer cylinder fixed connection is in the bottom both sides of braking frame, is provided with the slider in its section of thick bamboo, the both sides lateral wall of buffer cylinder has all been seted up with slider matched with spout, spout and fixedly connected with lug are passed at the both ends of slider, the lug is located outside the buffer cylinder, and its width is greater than the groove width of spout, the first spring of fixedly connected with between the top of slider and the bottom of braking frame, its bottom fixedly connected with buffer beam, the bottom and the fixedly connected with buffer board of buffer cylinder are run through to the bottom of buffer beam.

Preferably, the bottom surface of buffer board evenly is provided with a plurality of hemisphere rubber piece, and a pair of support of its top fixedly connected with, fixedly connected with guide arm between the support, the pole body cover of guide arm is equipped with a pair of driving block, the surface of driving block is seted up with guide arm matched with through-hole, the guide arm passes the through-hole, fixedly connected with second spring between driving block and the support, the second spring winding is at the pole body of guide arm, the top fixedly connected with a pair of connecting seat of driving block, fixedly connected with pivot between the connecting seat, the axle body swing joint of pivot has the connecting rod, the terminal fixedly connected with shaft of connecting rod, the axle body fixedly connected with gyro wheel of shaft, the gyro wheel laminating is on the bottom surface at the braking frame.

Compared with the prior art, the invention has the beneficial effects that:

1. the speed measuring sensor can monitor the speed of the overhead travelling crane in real time in the lifting process, and when the overhead travelling crane falls down rapidly due to the falling of a rope in the lifting process, the speed measuring sensor can monitor the speed abnormity in time and transmit control signals to the first brake mechanism and the second brake mechanism respectively through the control line;

2. the invention has good braking effect, and can carry out double braking on the overhead travelling crane when the speed sensor monitors that the speed is abnormal through the combined action of the first braking mechanism and the second braking mechanism so as to effectively slow down the falling speed of the overhead travelling crane, thereby playing the anti-falling protection effect;

3. the buffering mechanism can play a role in buffering when the overhead travelling crane falls to the ground through mutual matching of all the components in the buffering mechanism, so that the ground impact force on the buffering plate is greatly reduced, and the related components at the bottom of the overhead travelling crane are prevented from being damaged due to violent impact.

Drawings

FIG. 1 is a perspective view of a portion of the present invention;

FIG. 2 is a schematic view of the overall structure of the present invention;

FIG. 3 is a schematic structural view of the traveling block of the present invention;

FIG. 4 is a schematic structural diagram of a crown block according to the present invention;

FIG. 5 is a schematic structural view of a first braking mechanism according to the present invention;

FIG. 6 is a schematic structural view of a second brake mechanism according to the present invention;

FIG. 7 is a schematic structural view of a damper mechanism according to the present invention;

fig. 8 is an enlarged view of fig. 7 at a.

Reference numbers in the figures: 1. a frame body; 2. traveling vehicles; 3. a traction ring; 4. a wheel carrier; 5. a guide wheel; 6. a winch; 7. a hauling rope; 8. a crown block; 9. a suspension ring; 10. a suspension rope; 11. connecting blocks; 12. a movable groove; 13. mounting blocks; 14. a speed measuring sensor; 15. a fixed block; 16. a connecting rod; 17. a limiting pipe; 18. a first cylinder; 19. a brake plate; 20. a brake frame; 21. a brake wheel; 22. a vertical plate; 23. a second cylinder; 24. a brake pad; 25. a non-slip mat; 26. a buffer cylinder; 27. a slider; 28. a chute; 29. a bump; 30. a first spring; 31. a buffer rod; 32. a buffer plate; 33. a support; 34. a guide bar; 35. a transmission block; 36. a second spring; 37. a connecting seat; 38. a connecting rod; 39. and a roller.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1-8, the present invention provides a technical solution: a derrick lifting anti-drop protection mechanism for an oil drilling machine comprises a frame body 1, a traveling block 2 is arranged in the frame body 1, two side walls of the traveling block 2 are fixedly connected with traction rings 3, the top of the frame body 1 is fixedly connected with a pair of wheel carriers 4, a wheel shaft is fixedly connected between the wheel carriers 4, a guide wheel 5 is movably connected with a shaft body of the wheel shaft, a rope groove is formed in the surface of the guide wheel 5, a winch 6 is arranged on one side of the frame body 1, a traction rope 7 is wound on a roller of the winch 6, the traction rope 7 penetrates through the rope groove in the surface of the guide wheel 5, the tail end of the traction rope is divided into two strands and tied on the two traction rings 3 respectively, the roller can be driven to rotate by driving the winch 6 so as to tighten or loosen the traction rope 7, when the traction rope 7 is tightened or loosened, the traveling block 2 can be driven to move up and down by the traction rings 3, a fixed block 15 is fixedly connected to the top of the traveling block 2, connecting rods 16 are fixedly connected to two sides of the fixed block 15, the tail end of the connecting rod 16 is fixedly connected with a limiting pipe 17, the limiting pipe 17 is sleeved on the traction rope 7, the traction rope 7 can be limited through the limiting pipe 17, so that the influence of shaking on the stability of the traveling block 2 caused by the shaking in the traction process is prevented, the crown block 8 is arranged under the traveling block 2, the bottom of the crown block is fixedly connected with a suspension ring 9, a plurality of suspension ropes 10 are tied on the suspension ring 9, the tail ends of the suspension ropes 10 are fixedly connected with four corners at the top of the crown block 8, the crown block 8 can be driven by the suspension ropes 10 to move together when the traveling block 2 moves up and down, so that the lifting operation is realized, the side walls at two sides of the crown block 8 are fixedly connected with connecting blocks 11, the side walls at two sides of the frame 1 are respectively provided with a movable groove 12 matched with the connecting blocks 11, the tail ends of the connecting blocks 11 pass through the movable grooves 12 and are fixedly connected with mounting blocks 13, the mounting blocks 13 are positioned outside the frame 1, and speed measuring sensors 14 are arranged on the mounting blocks 13, the speed of the crown block 8 in the lifting process can be monitored in real time through the speed measuring sensor 14, a first brake mechanism and a second brake mechanism are respectively arranged above and below the crown block 8, the first brake mechanism comprises a first air cylinder 18, the first air cylinder 18 is arranged on the inner walls of two sides of the crown block 8, an output shaft of the first air cylinder penetrates through the side wall of the crown block 8 and is fixedly connected with a brake plate 19, the first air cylinder 18 is electrically connected with the speed measuring sensor 14 through a control line, when the rope falls off in the lifting process to cause the crown block 8 to fall down rapidly, the speed measuring sensor 14 can monitor abnormal speed in time, and transmits a control signal to the first air cylinder 18 through the control line, so as to drive the first air cylinder 18 to drive the brake plate 19 to move towards the inner wall of the frame body 1 until the brake plate 19 tightly abuts against the inner wall of the frame body 1, the second brake mechanism comprises a brake frame 20, the brake frame 20 is fixedly connected to the bottom of the crown block 8, the side walls of the two sides of the speed measuring sensor are both provided with openings, the inner walls of the openings are fixedly connected with wheel shafts, the shaft bodies of the wheel shafts are movably connected with brake wheels 21, the brake wheels 21 are attached to the inner wall of a frame body 1, the brake frame 20 can drive the brake wheels 21 to roll along the inner wall of the frame body 1 in the lifting process, the inner wall of the bottom of the brake frame 20 is fixedly connected with a vertical plate 22, two sides of the vertical plate 22 are both provided with second air cylinders 23, the tail ends of output shafts of the second air cylinders 23 are fixedly connected with brake blocks 24, the second air cylinders 23 are electrically connected with the speed measuring sensor 14 through control lines, the brake blocks 24 are arc-shaped, when a crown block 8 falls rapidly due to falling off of a rope in the lifting process, the speed measuring sensor 14 can timely monitor abnormal speed and transmit control signals to the second air cylinders 23 through the control lines, so as to drive the second air cylinders 23 to drive the brake blocks 24 to move towards the brake wheels 21, until the brake block 24 tightly supports against the surface of the brake wheel 21, the surface of the brake block 24 close to one side of the brake wheel 21 is provided with a layer of non-slip mat 25, the surface of the brake block 19 close to one side of the inner wall of the frame body 1 is also provided with a layer of non-slip mat 25, the non-slip mat 25 is of a rubber pad structure, herringbone non-slip lines are engraved on the surface of the non-slip mat 25, the friction force between the brake block 19 and the inner wall of the frame body 1 and between the brake block 24 and the surface of the brake wheel 21 can be respectively increased, so that the double braking effect can be achieved, the falling speed of the crown block 8 can be effectively reduced, the anti-falling effect can be achieved, a buffer mechanism is arranged below the brake frame 20, the buffer mechanism comprises a pair of buffer cylinders 26, the buffer cylinders 26 are fixedly connected to two sides of the bottom of the brake frame 20, slide blocks 27 are arranged in the cylinders, slide grooves 28 matched with the slide blocks 27 are arranged on the side walls of two sides of the buffer cylinders 26, and two ends of the slide blocks 27 pass through the slide grooves 28 and are fixedly connected with convex blocks 29, the bump 29 is positioned outside the buffer cylinder 26, the width of the bump is larger than the width of the chute 28, a first spring 30 is fixedly connected between the top of the slide block 27 and the bottom of the brake frame 20, the bottom of the first spring is fixedly connected with a buffer rod 31, the bottom end of the buffer rod 31 penetrates through the bottom of the buffer cylinder 26 and is fixedly connected with a buffer plate 32, when the overhead traveling crane 8 with the reduced speed falls to the ground under the action of gravity, the overhead traveling crane can firstly contact with the buffer plate 32, a plurality of hemispherical rubber blocks are uniformly arranged on the bottom surface of the buffer plate 32, the rubber blocks have elasticity and can elastically deform when being extruded, so that the buffering effect can be achieved, a pair of brackets 33 are fixedly connected with the top of the buffer plate 32, a guide rod 34 is fixedly connected between the brackets 33, a pair of transmission blocks 35 is sleeved on the rod body of the guide rod 34, through holes matched with the guide rod 34 are formed in the surface of the transmission blocks 35, the guide rod 34 penetrates through holes, and a second spring 36 is fixedly connected between the transmission blocks 35 and the brackets 33, the second spring 36 is wound on the rod body of the guide rod 34, the top of the transmission block 35 is fixedly connected with a pair of connecting seats 37, a rotating shaft is fixedly connected between the connecting seats 37, a connecting rod 38 is movably connected to the shaft body of the rotating shaft, the tail end of the connecting rod 38 is fixedly connected with a wheel shaft, a roller 39 is fixedly connected to the shaft body of the wheel shaft, the roller 39 is attached to the bottom surface of the brake frame 20, the buffer plate 32 is stressed to drive the slider 27 to move upwards along the chute 28 and compress the first spring 30, meanwhile, the roller 39 rolls towards two sides along the bottom surface of the brake frame 20, at the moment, the connecting rod 38 deflects to respectively drive the two transmission blocks 35 to slide towards two sides along the guide rod 34 and compress the second spring 36, and then the buffer effect can be further achieved through the common elastic reset effect of the first spring 30 and the second spring 36, so as to greatly reduce the ground impact force on the buffer plate 32, thereby avoiding damage to the associated components at the bottom of the crown block 8 due to severe impact.

The working principle is as follows: when the hoisting mechanism is used, firstly, electrical elements in the mechanism are externally connected with a control switch and a power supply through leads, when an oil drilling machine is hoisted, a roller of a winch 6 is driven to rotate, so that the traction rope 7 is tightened, the traction rope 7 drives a traveling block 2 to move upwards after being tightened, and when the traveling block 2 moves upwards, a crown block 8 can be driven to move together through a suspension rope 10, so that the hoisting operation of the oil drilling machine is realized, and the speed of the traveling block 8 can be monitored in real time through a speed measuring sensor 14 in the hoisting process; when the crown block 8 falls rapidly due to the falling of the rope in the lifting process, the speed measuring sensor 14 can monitor the speed abnormality in time, and transmit a control signal to the first air cylinder 18 and the second air cylinder 23 respectively through a control line, the first air cylinder 18 and the second air cylinder 23 which receive the control signal can drive the brake plate 19 and the brake block 24 to move towards the inner wall of the frame body 1 and the surface direction of the brake wheel 21 respectively until the brake plate 19 and the brake block 24 are tightly pressed against the inner wall of the frame body 1 and the surface of the brake wheel 21 respectively, so that the double braking effect can be achieved, the falling speed of the crown block 8 can be effectively slowed down, the anti-falling protection effect can be achieved, when the crown block 8 with the slowed speed falls to the ground under the action of gravity, the crown block can be firstly contacted with the buffer plate 32, the buffer plate 32 can drive the slide block 27 to move upwards along the chute 28 and compress the first spring 30 after being stressed, meanwhile, the roller 39 rolls along the bottom surface of the brake frame 20 to both sides, and at this time, the connecting rod 38 deflects to respectively drive the two driving blocks 35 to slide along the guide rods 34 to both sides and compress the second springs 36, and then the buffering effect can be achieved through the common elastic resetting effect of the first springs 30 and the second springs 36, so that the ground impact force applied to the buffer plate 32 is greatly reduced, and the related components at the bottom of the crown block 8 are prevented from being damaged due to violent impact.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. The utility model provides a derrick plays to rise anti-drop protection mechanism for oil-well rig, includes support body (1), its characterized in that: the traveling block is characterized in that a traveling block (2) is arranged in the frame body (1), the side walls of the two sides of the traveling block (2) are fixedly connected with traction rings (3), a pair of wheel carriers (4) is fixedly connected to the top of the frame body (1), a wheel shaft is fixedly connected between the wheel carriers (4), a guide wheel (5) is movably connected to the shaft body of the wheel shaft, a rope groove is formed in the surface of the guide wheel (5), a winch (6) is arranged on one side of the frame body (1), a traction rope (7) is wound on a roller of the winch (6), the traction rope (7) penetrates through the rope groove in the surface of the guide wheel (5), the tail end of the traction rope is divided into two strands and tied on the two traction rings (3) respectively, a crown block (8) is arranged under the traveling block (2), a suspension ring (9) is fixedly connected to the bottom of the crown block, a plurality of suspension ropes (10) are tied to the suspension ring (9), and the tail end of the suspension rope (10) is fixedly connected to four corners at the top of the crown block (8), the equal fixedly connected with connecting block (11) of both sides lateral wall of day car (8), the both sides lateral wall of support body (1) has all been seted up with connecting block (11) matched with activity groove (12), the end of connecting block (11) passes activity groove (12) and fixedly connected with installation piece (13), installation piece (13) are located outside support body (1), just install tacho sensor (14) on installation piece (13), the top and the below of day car (8) are provided with first arrestment mechanism and second arrestment mechanism respectively.

2. The derrick lifting anti-drop protection mechanism for the oil drilling rig according to claim 1, characterized in that: the top fixedly connected with fixed block (15) of tourist car (2), the equal fixedly connected with connecting rod (16) in both sides of fixed block (15), the spacing pipe of terminal fixedly connected with (17) of connecting rod (16), spacing pipe (17) cover is established on haulage rope (7).

3. The derrick lifting anti-drop protection mechanism for the oil drilling rig according to claim 1, characterized in that: the first brake mechanism comprises a first cylinder (18), the first cylinder (18) is installed on the inner walls of the two sides of the overhead traveling crane (8), an output shaft of the first cylinder penetrates through the side wall of the overhead traveling crane (8) and is fixedly connected with a brake plate (19), and the first cylinder (18) is electrically connected with the speed measuring sensor (14) through a control line.

4. The derrick lifting anti-drop protection mechanism for the oil drilling rig according to claim 3, characterized in that: second arrestment mechanism includes braking frame (20), braking frame (20) fixed connection is in the bottom of overhead traveling crane (8), and the opening has all been seted up to its both sides lateral wall, open-ended inner wall fixedly connected with shaft, the axle body swing joint of shaft has braked wheel (21), the inner wall at support body (1) is laminated in braked wheel (21), the bottom inner wall fixedly connected with riser (22) of braking frame (20), second cylinder (23) are all installed to the both sides of riser (22), the terminal fixedly connected with brake pads (24) of output shaft of second cylinder (23), just through control line electric connection between second cylinder (23) and tacho sensor (14), the below of braking frame (20) is provided with buffer gear.

5. The derrick lifting anti-drop protection mechanism for the oil drilling rig according to claim 4, characterized in that: the brake block (24) is arc-shaped, a layer of anti-slip mat (25) is arranged on the surface of one side, close to the brake wheel (21), of the brake block, a layer of anti-slip mat (25) is also arranged on the surface of one side, close to the inner wall of the frame body (1), of the brake block (19), the anti-slip mat (25) is of a rubber pad structure, and herringbone anti-slip lines are engraved on the surface of the anti-slip mat (25).

6. The derrick lifting anti-drop protection mechanism for the oil drilling rig according to claim 4, characterized in that: buffer gear includes a pair of buffer cylinder (26), buffer cylinder (26) fixed connection is in the bottom both sides of brake frame (20), is provided with slider (27) in its section of thick bamboo, both sides lateral wall of buffer cylinder (26) all seted up with slider (27) matched with spout (28), spout (28) and fixedly connected with lug (29) are passed at the both ends of slider (27), lug (29) are located outside buffer cylinder (26), and its width is greater than the groove width of spout (28), first spring (30) of fixedly connected with between the top of slider (27) and the bottom of brake frame (20), its bottom fixedly connected with buffer beam (31), the bottom and the fixedly connected with buffer board (32) of buffer cylinder (26) are run through to the bottom of buffer beam (31).

7. The derrick lifting anti-drop protection mechanism for the oil drilling rig according to claim 6, characterized in that: the bottom surface of the buffer plate (32) is uniformly provided with a plurality of hemispherical rubber blocks, the top of the buffer plate is fixedly connected with a pair of brackets (33), a guide rod (34) is fixedly connected between the brackets (33), a rod body of the guide rod (34) is sleeved with a pair of transmission blocks (35), the surface of each transmission block (35) is provided with a through hole matched with the guide rod (34), the guide rod (34) penetrates through the through hole, a second spring (36) is fixedly connected between each transmission block (35) and the corresponding bracket (33), the second spring (36) is wound on the rod body of the guide rod (34), the top of each transmission block (35) is fixedly connected with a pair of connecting seats (37), a rotating shaft is fixedly connected between the connecting seats (37), the shaft body of the rotating shaft is movably connected with a connecting rod (38), the tail end of the connecting rod (38) is fixedly connected with a wheel shaft, and the shaft body of the wheel shaft is fixedly connected with a roller (39), the roller (39) is attached to the bottom surface of the braking frame (20).