Bone fixing and angle adjusting device for orthopedic surgery

Abstract

The invention discloses a skeleton fixing and angle adjusting device for orthopedic surgery, and belongs to the technical field of medical instruments. The fixing and angle adjusting device comprises two coaxially-arranged lantern rings and telescopic rods annularly distributed on the sides, close to each other, of the two lantern rings. The needle threading seats are arranged on the sides, away from each other, of the lantern ring and used for allowing a steel nail to penetrate into the bone; the moving structure is arranged on the lantern ring and used for changing the angular position of the needle threading seats; the fixing and angle adjusting device further comprises tightening structures which are arranged on the inner sides of the two lantern rings and used for being fixed to limbs. According to the bone fixing and angle adjusting device for the orthopedic surgery, the tightening degree between the elastic ring and the limb can be conveniently controlled in the mode that the non-elastic rope is wound through the winding assembly to enable the elastic ring to be folded, so that the bone fixing and angle adjusting device adapts to fixation of different limbs in different shapes and sizes, meanwhile, stability in the bone steel nail puncturing process can be guaranteed, and the bone fixing and angle adjusting device is convenient to use. And the operation convenience is improved.

Description

Technical Field

[0001] The present application relates to the technical field of medical devices, and in particular to a bone fixation and angle adjustment device for orthopedic surgery. Background Art

[0002] Fracture treatment in orthopedic surgery is a complex and challenging process, especially when it involves long bones, joints, spine and other parts. How to accurately fix the fracture and ensure smooth fracture healing has become one of the key issues in clinical treatment.

[0003] The Chinese utility model patent with announcement number CN220213049U discloses an adjustable bone external fixator. It improves work efficiency and brings convenience to operators by adjusting the length between the distal ring and the proximal ring. However, the distal ring and the proximal ring used to be put on the outside of the limb in this device are designed with fixed sizes. In actual surgery, there are significant differences in the size and shape of the limbs of different patients, and the fixed-size rings are often not suitable for all patients' limbs. At the same time, in actual application, additional tools or manual positioning of the distal ring and the proximal ring are required to perform steel bar puncture fixation. The operation is inconvenient and it is difficult to ensure its stability.

[0004] Therefore, the present application provides a bone fixation and angle adjustment device for orthopedic surgery to solve the above problems. Summary of the invention

[0005] The present application provides a bone fixation and angle adjustment device for orthopedic surgery, aiming to solve the problems raised in the background technology that the distal ring and the proximal ring of the existing bone fixation device for orthopedic surgery are difficult to adapt to the limb sizes of different patients due to the fixed size design, and require additional tools or manual positioning, which is inconvenient to operate and difficult to ensure stability.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical solutions: a bone fixation and angle adjustment device for orthopedic surgery, comprising two coaxially arranged rings, telescopic rods distributed in an annular manner on the sides of the two rings close to each other, a needle holder arranged on the sides of the rings away from each other for allowing a steel nail to penetrate into the bone, and a movable structure arranged on the rings for changing the angle position of the needle holder;

[0007] The fixing and angle adjustment device also includes a tightening structure arranged on the inner side of the two collars for fixing to the limb;

[0008] The tightening structure comprises elastic rings respectively arranged on the inner sides of the two sleeves, inelastic ropes respectively movably arranged on the two sleeves and sleeved on the outer sides of the corresponding elastic rings for closing the elastic rings, and a winding assembly arranged on the two sleeves for winding or loosening the two inelastic ropes;

[0009] The inner sides of the two elastic rings are movably provided with convex balls distributed in an annular array, and the side of the two rings close to each other is provided with a driving mechanism connected to the winding assembly for pushing out or falling back the convex balls; through the movable structure arranged on the ring, the angle position of the needle seat can be easily changed to be suitable for fixation of different fracture types and positions, thereby improving the flexibility of the device. At the same time, the design of the telescopic rod further increases the flexibility of the device, and the length can be adjusted as needed. Elastic rings are arranged in the two rings, and the winding assembly is used to wind up the non-elastic rope to make the elastic ring close. The tightening degree can be conveniently controlled to adapt to the shapes and sizes of different limbs, and the stability during the puncture of the bone steel nail can also be ensured, thereby improving the convenience of operation. The convex ball is driven by the driving mechanism connected to the winding assembly to be repeatedly pushed out and fallen back, and the muscles of the limbs can be massaged and relaxed while being fixed and tightened, which helps to reduce the resistance and pain during puncture, makes the operation process smoother, and can also reduce the patient's postoperative discomfort.

[0010] Preferably, in order to facilitate the connection and use of the non-elastic rope, an active cavity is opened at the position of the ring corresponding to the non-elastic rope, and connecting blocks distributed in a ring array are fixedly arranged in the active cavity. The two ends of the non-elastic rope pass through the multiple connecting blocks in sequence and are movably connected with the multiple connecting blocks, and the two end edges of the outer side of the elastic ring are fixedly connected to the two end edges of the inner side of the active cavity; this design makes the connection of the non-elastic rope more stable, and also facilitates the subsequent winding and loosening operations.

[0011] Preferably, in order to facilitate the winding or loosening of the inelastic rope, the winding assembly includes a driving shaft rotatably connected to the two rings at positions corresponding to the active chambers and fixedly connected to one end of the corresponding inelastic rope, a driven shaft rotatably connected to one side of the two rings corresponding to the driving shaft and fixedly connected to the other end of the corresponding inelastic rope, a driving gear and a driven gear respectively fixedly sleeved on the driving shaft and the corresponding driven shaft and meshed, and a motor fixedly arranged on one of the rings for driving the corresponding driving shaft to rotate, the two driven shafts are fixedly connected to the two ends of one of the telescopic rods, and the two ends of the telescopic rod are respectively fixedly connected to the two rings; through the meshing transmission of the driving shaft, the driven shaft, the driving gear and the driven gear, and the drive of the motor, the automatic winding and loosening of the inelastic rope can be achieved, and this design greatly improves the efficiency and convenience of the operation.

[0012] Preferably, in order to meet the needs of different fracture types, the needle seats are provided in plurality, and the plurality of needle seats are evenly distributed on the ring; by providing multiple needle seats and evenly distributing them on the ring, the fixation needs of different fracture types and positions can be adapted. This design makes the device more widely applicable in surgery and can meet the needs of more patients.

[0013] Preferably, in order to facilitate the fixing of the angle and position of the needle seat, the movable structure includes a U-shaped clamp slidably connected to the edge of the ring corresponding to the active cavity and fixedly connected to the needle seat, and a fastening screw screwed on the outside of the U-shaped clamp for abutting against the outside of the ring; the angle and position of the needle seat can be conveniently adjusted by sliding the U-shaped clamp on the ring and screwing the fastening screw on the outside of the U-shaped clamp. This design makes the device more flexible during surgery and can adapt to the needs of different surgical scenarios.

[0014] Preferably, in order to facilitate the use of the convex ball, a cavity is provided in the elastic ring at the position of the convex ball; this design enables the convex ball to be ejected and returned more smoothly during the massage process, thereby improving the massage effect.

[0015] Preferably, in order to facilitate the ejection and return of the convex ball, the driving mechanism includes air bags fixedly arranged in the two cavities and located on the outer sides of the corresponding convex balls for expansion or contraction, and two air cylinder assemblies respectively arranged on one side of the two rings close to each other and connected to the corresponding driving shaft away from the driving gear for inflating or deflating the air bags; through the expansion or contraction of the air bags, the convex ball can be driven to be ejected or returned in the elastic ring, thereby achieving a massage effect on the limbs.

[0016] Preferably, in order to achieve the expansion or contraction of the airbag, the air cylinder assembly includes a rotating wheel fixedly connected to the end of the driving shaft away from the driving gear and located on the side where the two rings are close to each other, an eccentric shaft fixedly connected to the rotating wheel, an air cylinder fixedly arranged on the ring corresponding to the side of the eccentric shaft, a piston that moves laterally in the air cylinder, a push rod that laterally penetrates the air cylinder near the end of the eccentric shaft and is fixedly connected to the piston, and a connecting pipe that is fixedly connected to the end of the air cylinder away from the push rod and communicates with the airbag, the push rod is slidably connected to the air cylinder, and the push rod and the eccentric shaft are rotatably connected; such a design can ensure that while the elastic ring is tightened or loosened, the airbag can also be inflated and evacuated synchronously, and the convex ball can be lifted up or dropped back by the expansion or contraction of the airbag.

[0017] The bone fixation and angle adjustment device for orthopedic surgery can conveniently change the angle position of the needle seat through the movable structure arranged on the collar, so as to be suitable for fixation of different fracture types and positions, thereby improving the flexibility of the device. Meanwhile, the design of the telescopic rod further increases the flexibility of the device, and the length can be adjusted as needed.

[0018] The bone fixation and angle adjustment device for orthopedic surgery can conveniently control the degree of tightening between the elastic ring and the limb by winding up the non-elastic rope through the winding component, so as to adapt to the fixation of limbs of different shapes and sizes, and at the same time ensure the stability during the puncture of the bone steel nail, thereby improving the convenience of operation;

[0019] The bone fixation and angle adjustment device for orthopedic surgery drives the convex ball to be repeatedly ejected and retracted through a driving mechanism connected to the winding component, which can massage and relax the muscles of the limbs while fixing and tightening, helping to reduce resistance and pain during puncture, making the operation process smoother, and also reducing the patient's postoperative discomfort. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of the structure of a bone fixation and angle adjustment device for orthopedic surgery Figure 1 ;

[0021] Figure 2 A schematic diagram of the structure of a bone fixation and angle adjustment device for orthopedic surgery Figure 2 ;

[0022] Figure 3 It is a structural schematic diagram of a collar and a tightening structure in a bone fixation and angle adjustment device for orthopedic surgery;

[0023] Figure 4 A cross-sectional view of a tightening structure of a bone fixation and angle adjustment device for orthopedic surgery;

[0024] Figure 5 The present invention is a cross-sectional view of an elastic ring and a driving mechanism of a bone fixation and angle adjustment device used in orthopedic surgery.

[0025] In the figure:

[0026] 1. Ring; 11. Active cavity; 12. Connecting block;

[0027] 2. Telescopic rod;

[0028] 3. tightening structure; 31. elastic ring; 32. non-elastic rope; 33. winding assembly; 331. driving shaft; 332. driven shaft; 333. driving gear; 334. driven gear; 335. motor;

[0029] 4. Needle threading seat;

[0030] 5. Moving structure; 51. U-shaped clamp; 52. Fastening screw;

[0031] 6. Convex ball;

[0032] 7. Driving mechanism; 71. Air bag; 72. Air cylinder assembly; 721. Rotating wheel; 722. Eccentric shaft; 723. Air cylinder; 724. Piston; 725. Push rod; 726. Connecting pipe. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0034] This embodiment provides a bone fixation and angle adjustment device for orthopedic surgery, such as Figure 1-Figure 5 As shown, the fixing and angle adjustment device comprises two coaxially arranged rings 1, a telescopic rod 2 distributed in an annular shape on the side of the two rings 1 close to each other, a needle seat 4 arranged on the side of the rings 1 away from each other for allowing the steel nail to penetrate into the bone, and a moving structure 5 arranged on the rings 1 for changing the angle position of the needle seat 4; the fixing and angle adjustment device also comprises a tightening structure 3 arranged on the inner side of the two rings 1 for fixing with the limb; the tightening structure 3 comprises elastic rings 31 respectively arranged on the inner sides of the two rings 1, inelastic ropes 32 respectively movably arranged on the two rings 1 and sleeved on the outer sides of the corresponding elastic rings 31 for closing the elastic rings 31, and a winding assembly 33 arranged on the two rings 1 for winding or loosening the two inelastic ropes 32; convex balls 6 distributed in an annular array are movably arranged inside the inner sides of the two elastic rings 31, and a driving mechanism 7 connected to the winding assembly 33 for ejecting or falling back the convex balls 6 is arranged on the side of the two rings 1 close to each other.

[0035] Among them, in order to facilitate the connection and use of the inelastic rope 32, an active cavity 11 is opened at the position of the ring 1 corresponding to the inelastic rope 32, and connecting blocks 12 distributed in a ring array are fixedly arranged in the active cavity 11. The two ends of the inelastic rope 32 pass through the multiple connecting blocks 12 in turn and are movably connected with the multiple connecting blocks 12, and the two end edges of the outer side of the elastic ring 31 are fixedly connected to the two end edges of the inner side of the active cavity 11; this design makes the connection of the inelastic rope 32 more stable, and at the same time, when the inelastic rope 32 is rolled up, the inelastic rope 32 can squeeze the outer side of the elastic ring 31 and radially contract.

[0036] When in use, first put the two rings 1 on the limbs where the bones need to be fixed, and then pull the two rings 1 according to the height or length of the bones to be fixed. At this time, the distance between the two rings 1 can be adjusted through the telescopic connection of the telescopic rod 2 to meet different fixing requirements. Then, start the winding component 33 to drive the non-elastic rope 32 set on the two rings 1 to wind up. Since the outer two end edges of the elastic ring 31 are fixedly connected to the inner two end edges of the active cavity 11, as the non-elastic rope 32 is rolled up and tightened, the non-elastic rope 32 will squeeze the outer side of the elastic ring 31, causing the elastic ring 31 to radially shrink, thereby shrinking and tightening on different limbs to ensure further fixation of the two rings 1 to the limbs. However, since the driving mechanism 7 is connected to the winding assembly 33, when the non-elastic rope 32 is wound by starting the winding assembly 33, the driving mechanism 7 will synchronously repeatedly lift or drop the convex ball 6 set in the elastic ring 31, so that the elastic ring 31 is gradually retracted on the limb, and the limb can be massaged by the lifting or falling of the convex ball 6 to relax the muscles before the steel nail puncture. Afterwards, after the device is fixed on the limb by tightening the elastic ring 31, the position and angle of the needle seat 4 can be changed by adjusting the moving structure 5 to meet the needs of different bone punctures. Conversely, after starting the winding assembly 33 to drive the elastic ring 31 to relax, the fixation of the two rings 1 to the limb can be released.

[0037] Specifically, the winding assembly 33 includes a driving shaft 331 which is rotatably connected to the positions of the corresponding active chambers 11 on the two collars 1 and fixedly connected to one end of the corresponding inelastic rope 32, a driven shaft 332 which is rotatably connected to one side of the corresponding driving shaft 331 on the two collars 1 and fixedly connected to the other end of the corresponding inelastic rope 32, a driving gear 333 and a driven gear 334 which are respectively fixedly sleeved on the driving shaft 331 and the corresponding driven shaft 332 and meshed, and a motor 335 which is fixedly arranged on one of the collars 1 and is used to drive the corresponding driving shaft 331 to rotate, the two driven shafts 332 are fixedly connected to the two ends of one of the telescopic rods 2, and the two ends of the telescopic rod 2 are respectively fixedly connected to the two collars 1;

[0038] When it is necessary to start the winding assembly 33 to wind up the inelastic rope 32 to close the elastic ring 31, the motor 335 can be started to drive the connected driving shaft 331 to rotate. Since a driven shaft 332 is provided on one side of the driving shaft 331, and a driving gear 333 and a driven gear 334 are respectively connected to the driving shaft 331 and the driven shaft 332, the driving gear 333 and the driven gear 334 are meshed. Therefore, when the motor 335 drives the connected driving shaft 331 to rotate, the corresponding driven shaft 332 will also rotate synchronously in the opposite direction. Since the driven shafts 332 on the two rings 1 are connected through one of the telescopic rods 2, when one of the driven shafts 332 rotates, the other driven shaft 332 will rotate synchronously. The shaft 332 will also rotate synchronously. At the same time, the other driven shaft 332 and the driving shaft 331 set on one side thereof will also rotate synchronously due to the meshing transmission of the driven gear 334 and the driving gear 333 connected thereto. Therefore, when the motor 335 is started, the driving shaft 331 and the driven shaft 332 set on the two rings 1 will rotate synchronously towards each other. As the driving shaft 331 and the driven shaft 332 set on the two rings 1 rotate towards each other, the two ends of the inelastic rope 32 set on the two rings 1 will be synchronously retracted to the correspondingly connected driving shaft 331 and the driven shaft 332. Afterwards, as the two inelastic ropes 32 are retracted, the two elastic rings 31 can be synchronously retracted and tightened on the limb.

[0039] In addition, in order to facilitate the use of the convex ball 6, a cavity is provided in the elastic ring 31 at the position of the convex ball 6; the design of the cavity enables the convex ball 6 to be pushed out and returned more smoothly during the massage process, thereby improving the massage effect.

[0040] Furthermore, the driving mechanism 7 includes air bags 71 respectively fixedly arranged in the two cavities and located outside the corresponding convex balls 6 for expansion or contraction, and two sleeves 1 are respectively arranged on one side close to each other and connected to the corresponding driving shaft 331 away from the driving gear 333 for inflating or deflating the air bags 71. The sleeve assembly 72 includes a rotating wheel 721 fixedly connected to one end of the driving shaft 331 away from the driving gear 333 and located on the side close to each other of the two sleeves 1, and a rotating wheel 721 fixedly connected to the rotating wheel 7 21, an eccentric shaft 722 on the sleeve 1, an air cylinder 723 fixedly arranged on one side of the eccentric shaft 722 on the sleeve 1, a piston 724 moving laterally in the air cylinder 723, a push rod 725 laterally penetrating one end of the air cylinder 723 close to the eccentric shaft 722 and fixedly connected to the piston 724, and a connecting pipe 726 fixedly connected to one end of the air cylinder 723 away from the push rod 725 and communicating with the air bag 71, the push rod 725 is slidably connected to the air cylinder 723, and the push rod 725 and the eccentric shaft 722 are rotatably connected;

[0041] When the starting motor 335 drives the driving shafts 331 set on the two collars 1 to rotate, the rotating wheel 721 connected to each driving shaft 331 will also rotate accordingly. As the rotating wheel 721 rotates, the eccentric shaft 722 set thereon will also rotate synchronously. Since the eccentric shaft 722 is eccentrically set, it will periodically push the push rod 725 connected thereto. Under the pushing action of the eccentric shaft 722, the push rod 725 will drive the piston 724 to repeatedly move horizontally in the gas cylinder 723. When the piston 724 moves toward one end close to the connecting pipe 726, the gas in the gas cylinder 723 is compressed. The airbag 71 will shrink and be filled into the airbag 71 through the connecting tube 726. The airbag 71 will gradually expand as the gas is filled, thereby pushing up the convex ball 6 that is movably arranged in the airbag. When the piston 724 moves to the other end away from the connecting tube 726, the gas in the airbag 71 will be sucked back into the air cylinder 723 through the connecting tube 726. The airbag 71 will shrink as the gas is extracted. Then the convex ball 6 will not be affected by the expansion push force of the airbag 71, but will fall back into the airbag. By repeatedly pushing out or falling back of the convex ball 6, the muscles can be massaged and relaxed while the elastic ring 31 is contracted and tightened.

[0042] It is understandable that there are multiple needle seats 4, and the multiple needle seats 4 are evenly distributed on the ring 1; by providing multiple needle seats 4 and evenly distributing them on the ring 1, different numbers of needle seats 4 can be used according to the type and location of the fracture to meet different surgical needs.

[0043] Furthermore, the moving structure 5 includes a U-shaped clip 51 which is slidably connected to the edge of the corresponding active cavity 11 of the collar 1 and fixedly connected to the needle holder 4, and a fastening screw 52 which is screwed to the outside of the U-shaped clip 51 and is used to abut against the outside of the collar 1;

[0044] The user can manually push the needle seat 4 to reach the desired angular position as needed. When the needle seat 4 is adjusted to the desired angle, the user rotates the fastening screw 52 to make its end tightly abut against the outer surface of the ring 1. As the fastening screw 52 rotates and is gradually tightened, the gap between the U-shaped clip 51 and the ring 1 gradually decreases until a firm fixing effect is achieved. At this time, the needle seat 4 is firmly locked at the desired angular position. Conversely, the user only needs to rotate the fastening screw 52 in the opposite direction to gradually loosen it and withdraw it from the abutment state with the ring 1, so as to manually adjust the position and angle of the needle seat 4.

[0045] The above is only a preferred specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can make equivalent substitutions or changes according to the technical solution and concept of the present application within the technical scope disclosed in the present application, which should be covered by the protection scope of the present application.

Claims

1. A bone fixation and angle adjustment device for orthopedic surgery, comprising two coaxially arranged collars (1), a telescopic rod (2) distributed in an annular shape on the side of the two collars (1) close to each other, a needle holder (4) arranged on the side of the collars (1) far away from each other for allowing a steel nail to penetrate into a bone, and a moving structure (5) arranged on the collars (1) for changing the angle position of the needle holder (4); Features: The fixing and angle adjustment device further comprises a tightening structure (3) arranged on the inner side of the two collars (1) for fixing to the limb; The tightening structure (3) comprises elastic rings (31) respectively arranged on the inner sides of the two sleeve rings (1), non-elastic ropes (32) respectively movably arranged on the two sleeve rings (1) and sleeved on the outer sides of the corresponding elastic rings (31) for closing the elastic rings (31), and a winding assembly (33) arranged on the two sleeve rings (1) for winding or loosening the two non-elastic ropes (32); The inner sides of the two elastic rings (31) are both movably provided with convex balls (6) distributed in a ring array, and the side of the two sleeve rings (1) close to each other is provided with a driving mechanism (7) connected to the winding assembly (33) for pushing out or falling back the convex balls (6).

2. The bone fixation and angle adjustment device for orthopedic surgery according to claim 1, characterized in that: The sleeve ring (1) is provided with an active cavity (11) at a position corresponding to the non-elastic rope (32), and connecting blocks (12) distributed in a ring array are fixedly arranged in the active cavity (11), and two ends of the non-elastic rope (32) are sequentially passed through a plurality of the connecting blocks (12) and are movably connected to the plurality of the connecting blocks (12), and the outer two end edges of the elastic ring (31) are fixedly connected to the inner two end edges of the active cavity (11).

3. The bone fixation and angle adjustment device for orthopedic surgery according to claim 2, characterized in that: The winding assembly (33) comprises a driving shaft (331) rotatably connected to the two sleeves (1) at positions corresponding to the active chambers (11) and fixedly connected to one end of the corresponding inelastic rope (32), a driven shaft (332) rotatably connected to one side of the two sleeves (1) corresponding to the driving shaft (331) and fixedly connected to the other end of the corresponding inelastic rope (32), a driving gear (333) and a driven gear (334) respectively fixedly sleeved on the driving shaft (331) and the corresponding driven shaft (332) and meshed, and a motor (335) fixedly arranged on one of the sleeves (1) for driving the corresponding driving shaft (331) to rotate, the two driven shafts (332) being fixedly connected to the two ends of one of the telescopic rods (2), and the two ends of the telescopic rod (2) being fixedly connected to the two sleeves (1).

4. The bone fixation and angle adjustment device for orthopedic surgery according to claim 2, characterized in that: A plurality of needle threading seats (4) are provided, and the plurality of needle threading seats (4) are evenly distributed on the collar (1).

5. The bone fixation and angle adjustment device for orthopedic surgery according to claim 4, characterized in that: The movable structure (5) comprises a U-shaped clip (51) slidably connected to the edge of the collar (1) corresponding to the active cavity (11) and fixedly connected to the needle holder (4), and a fastening screw (52) screwed on the outside of the U-shaped clip (51) for abutting against the outside of the collar (1).

6. The bone fixation and angle adjustment device for orthopedic surgery according to claim 3, characterized in that: A cavity is provided in the elastic ring (31) at the position of the convex ball (6).

7. The bone fixation and angle adjustment device for orthopedic surgery according to claim 6, characterized in that: The driving mechanism (7) comprises an air bag (71) fixedly arranged in the two cavities and located outside the corresponding convex ball (6) for expansion or contraction, and an air cylinder assembly (72) arranged on two sides of the two collars (1) close to each other and connected to the corresponding driving shaft (331) away from the driving gear (333) for inflating or deflating the air bag (71).

8. The bone fixation and angle adjustment device for orthopedic surgery according to claim 7, characterized in that: The air cylinder assembly (72) comprises a rotating wheel (721) fixedly connected to an end of the driving shaft (331) away from the driving gear (333) and located on a side where the two collars (1) are close to each other, an eccentric shaft (722) fixedly connected to the rotating wheel (721), an air cylinder (723) fixedly arranged on a side of the collar (1) corresponding to the eccentric shaft (722), a piston (724) that moves transversely in the air cylinder (723), a push rod (725) that transversely penetrates an end of the air cylinder (723) close to the eccentric shaft (722) and is fixedly connected to the piston (724), and a connecting pipe (726) that is fixedly connected to an end of the air cylinder (723) away from the push rod (725) and communicates with the air bag (71), wherein the push rod (725) is slidably connected to the air cylinder (723), and the push rod (725) and the eccentric shaft (722) are rotatably connected.

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