Dilation sheathing canal fixing device for percutaneous biliary tract puncture fistulization
By designing a expansion sheath fixing device including an abdominal wall fitting plate, a movable adjustment bracket and a clamp, the problem of the expansion sheath easy to displace and fall off during the operation is solved, and stable fixation is achieved, reducing the operating burden of the operator and assistant, and ensuring the smooth progress of the operation.
Patent Information
- Application Number
- CN202422132805.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-02
- Publication Date
- 2025-07-11
- Estimated Expiration
- 2034-09-02
AI Technical Summary
In the prior art, the dilated sheath is prone to displacement and fall off when the surgical operation instrument enters and exits, resulting in surgical failure or complications, and the operator and assistant have a heavy burden on operation.
An expansion sheath fixing device including an abdominal wall fitting plate, a movable adjustment bracket and a clamp is designed, and is fixed to the abdominal wall through an adhesive layer, and the multi-angle adjustment and fixation of the expansion sheath is achieved using the connecting rod and universal ball groove structure of the movable adjustment bracket.
Effectively fix the dilated sheath to avoid displacement and fall off, reduce the work burden of the surgeon and assistant, and ensure the smooth progress of the operation.
Smart Images
Figure CN223081735U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of medical devices, and particularly relates to a fixing device for a dilatation sheath tube for percutaneous biliary puncture and fistulation. Background Art
[0002] Biliary calculi can occur in the common bile duct, gallbladder and common hepatic duct, and can also occur in the confluence area of the left and right hepatic ducts and the intrahepatic biliary duct system; they can be diffusely multiple or limited to a certain hepatic segment or lobar bile duct. Due to the many branches of the intrahepatic bile ducts and possible anatomical variations, patients with a history of multiple biliary surgeries are prone to adhesions in the abdominal cavity, the liver is deformed by traction and inflamed and atrophied, and the location, quantity, size, etc. of biliary calculi are not the same. Therefore, the treatment of especially complex biliary calculi is relatively difficult. How to improve the stone extraction rate and minimize the invasiveness of treatment is the difficulty in the treatment of this disease.
[0003] The basic principle of minimally invasive surgical treatment of hepatolithiasis is still the "twenty-character" principle of "removing the focus, removing all stones, correcting stenosis, ensuring unobstructed drainage, and preventing recurrence". At present, the treatment of biliary calculi is mainly surgical. Traditional stone extraction surgical methods include open laparotomy and laparoscopic hepatectomy with bile duct exploration, endoscopic retrograde cholangiopancreatography for stone extraction, etc. However, traditional stone extraction surgeries are associated with large trauma, high costs, and slow postoperative recovery. Moreover, due to factors such as inflammation, anatomical stenosis, and easy stone residue, the postoperative stone recurrence rate can be as high as 70%. In addition, secondary stone extraction surgery causes great physical pain and economic burden to patients. In addition, with the development of the combined technology of choledochoscope, duodenoscope and laparoscope, the cure rate of multiple bile duct stones has been significantly improved, but there are still certain limitations in the treatment of complex intrahepatic and extrahepatic bile duct stones.
[0004] Percutaneous transhepatic cholangioscopic lithotripsy (PTCSL) uses an internal dilation sheath to establish a direct channel connecting the hepatic bile duct to the outside world, enabling the instruments to not come into direct contact with the hepatic tissue of the fistula tract throughout the process. It can directly reach the target bile ducts of grades III-IV in the patient's liver, effectively observing the states of bleeding, edema, etc. of the bile duct mucosa in the patient, and carefully observing the size, number, shape, etc. of the hepatobiliary duct stones in the patient. By dilating the sinus tract to 14F or 18F, rigid choledochoscopy can be performed simultaneously for lithotripsy and stone extraction. When the patient's fistula tract is dilated, a dilation sheath can be inserted. Since the dilation sheath tightly covers the bile duct with the stone, a direct channel connecting the hepatic bile duct to the outside world is established, avoiding the entry of lithotripsy into the patient's abdominal cavity and causing complications. And it is beneficial to flush out the lithotripsy with flowing water, improving the stone extraction efficiency. With the support and protection of the dilation sheath, the phenomena of fistula tract bleeding and bile peritonitis are avoided. Compared with the traditional stone extraction surgery, the operation of the internal dilation sheath combined with the rigid choledochoscope has the advantages of fast stone extraction, large quantity, and saving operation time. Currently, during clinical surgical operations, it is often necessary for the surgeon or assistant to fix the dilation sheath by hand. However, this method of fixing the sheath has the following problems: (1) It will impose a burden on the operation of the surgeon or assistant, and the fixer is prone to fatigue and unable to fix it for a long time; (2) The manual fixation has insufficient stability. When the surgical operation instruments enter and exit the dilation sheath, problems such as displacement and detachment of the dilation sheath are likely to occur, leading to surgical failure and even serious complications such as bile leakage and bleeding. Utility Model Content
[0005] The technical problem to be solved by this utility model is to provide a fixing device for the dilation sheath of percutaneous transhepatic biliary fistula. This fixing device for the dilation sheath can not only effectively fix the dilation sheath, but also be applicable to fixing dilation sheaths at different orientations and inclination angles, avoiding problems such as displacement and detachment when surgical operation instruments enter and exit, being beneficial to ensuring the smooth progress of surgical treatment, and reducing the work burden of the surgeon and assistant. The adopted technical solution is as follows:
[0006] A fixing device for the dilation sheath of percutaneous transhepatic biliary fistula, characterized in that it includes an abdominal wall fitting plate, a movable adjustment bracket, and a clamp for clamping the dilation sheath; an adhesive layer is provided on the bottom surface of the abdominal wall fitting plate, and a connecting block is provided on the top surface of the abdominal wall fitting plate; the movable adjustment bracket includes a plurality of connecting rods that are movably connected in sequence from top to bottom, the lower end of the lowermost connecting rod is installed on the connecting block, and the clamp is installed at the upper end of the uppermost connecting rod.
[0007] During the percutaneous transhepatic biliary drainage (PTBD) procedure, a gastric tube and a urinary catheter are indwelled in the patient. After general anesthesia with tracheal intubation and surgical site disinfection, the target bile duct is punctured under real-time guidance of DSA and B-ultrasound. After bile is aspirated and seen, cholangiography is performed to confirm entry into the target bile duct. The condition of the bile duct is observed. Then, a disposable biliary dilator is slowly and gently advanced along the guide wire into the intrahepatic bile duct, and the fistula tract is gradually dilated from 8F to 14 - 18F. Then, a dilatation sheath is inserted. According to the position of the dilatation sheath, the abdominal wall fitting plate of the above-mentioned dilatation sheath fixing device is attached to the corresponding position on the patient's abdominal wall through its adhesive layer. Then, the relative positions between the connecting rods of the movable adjustment bracket are adjusted to change the height position and inclination angle of the clamp, so that the clamp is in a position where it can clamp the dilatation sheath, facilitating the clamping and fixing of the dilatation sheath by the clamp, and enabling the dilatation sheath to maintain a certain inclination angle and orientation position throughout the operation. Subsequently, the original super-stiff guide wire is retained, the end of the guide wire is passed through the working channel inside the rigid choledochoscope, and the choledochoscope is slowly inserted along the guide wire. At the same time, the water pressure is turned on, and the rigid choledochoscope is advanced along the guide wire into the sheath to explore the bile duct. This dilatation sheath fixing device can effectively fix the dilatation sheath, and is applicable to fixing dilatation sheaths at different orientations and inclination angle positions, which can avoid problems such as displacement and detachment during the entry and exit of surgical instruments, facilitating the smooth progress of the surgical treatment. Moreover, since there is no need for the surgeon and the assistant to hold the dilatation sheath during the operation, the work burden of the surgeon and the assistant is reduced.
[0008] As a preferred embodiment of the present utility model, the abdominal wall fitting plate is made of medical silicone or medical-grade plastic (such as PVC).
[0009] As a preferred embodiment of the present utility model, each connecting rod of the movable adjustment bracket and the clamp are made of medical-grade plastic (such as polyethylene).
[0010] As a preferred embodiment of the present utility model, the adhesive layer is made of bioadhesive.
[0011] As a preferred embodiment of the present utility model, the movable adjustment bracket includes two connecting rods, namely a first connecting rod and a second connecting rod from bottom to top; a universal ball groove is provided on the top surface of the connecting block, a universal ball is provided at the lower end of the first connecting rod, and the universal ball is installed in the universal ball groove; the lower end of the second connecting rod is rotatably connected to the upper end of the first connecting rod through a first pin shaft, and the fixture is rotatably connected to the upper end of the second connecting rod through a second pin shaft, and the second pin shaft is parallel to the first pin shaft. With this structure, through the cooperation between the universal ball and the universal ball groove, the first connecting rod can be horizontally rotated and swung up and down around the connecting block; the second connecting rod can swing up and down relative to the first connecting rod around the first pin shaft to change the included angle between the second connecting rod and the first connecting rod, and the fixture can swing up and down relative to the second connecting rod around the second pin shaft to change the included angle between the fixture and the second connecting rod, thereby realizing the adjustment of the orientation and tilt angle position of the fixture and the dilatation sheath tube thereon.
[0012] As a further preferred embodiment of the present utility model, the first pin shaft is fixedly installed at the upper end of the first connecting rod, a first through hole is provided at the lower end of the second connecting rod, the lower end of the second connecting rod is sleeved on the first pin shaft through the first through hole, and a first friction sleeve is installed on the first pin shaft, and the first friction sleeve is in close contact with the inner wall of the first through hole; the second pin shaft is fixedly installed on the fixture, a second through hole is provided at the upper end of the second connecting rod, the upper end of the second connecting rod is sleeved on the second pin shaft through the second through hole, and a second friction sleeve is installed on the second pin shaft, and the second friction sleeve is in close contact with the inner wall of the second through hole. The first friction sleeve and the second friction sleeve can be made of rubber sleeves, plastic sleeves or metal sleeves. The first friction sleeve is used to fix the angular position rotated by the second connecting rod and play a role in positioning the second connecting rod; the second friction sleeve is used to fix the angular position rotated by the fixture and play a role in positioning the fixture.
[0013] As another preferred embodiment of the present utility model, the movable adjustment bracket includes three connecting rods, namely the first connecting rod, the second connecting rod, and the third connecting rod from bottom to top; universal ball grooves are provided on the top surface of the connecting block, the lower end and the upper end of the second connecting rod, and the bottom of the fixture. Universal balls are provided at the lower end and the upper end of the first connecting rod, the lower end and the upper end of the third connecting rod. The universal ball at the lower end of the first connecting rod is installed in the universal ball groove on the top surface of the connecting block, the universal ball at the upper end of the first connecting rod is installed in the universal ball groove at the lower end of the second connecting rod, the universal ball at the lower end of the third connecting rod is installed in the universal ball groove at the upper end of the second connecting rod, and the universal ball at the upper end of the third connecting rod is installed in the universal ball groove at the bottom of the fixture. With this structure, through the cooperation between each universal ball and the corresponding universal ball groove, the first connecting rod can rotate horizontally and swing up and down around the connecting block, the second connecting rod can rotate horizontally and swing up and down around the upper end of the first connecting rod, and the third connecting rod can rotate horizontally and swing up and down around the upper end of the second connecting rod, thereby realizing the adjustment of the orientation and tilt angle position of the fixture and the dilatation sheath tube thereon.
[0014] As another preferred embodiment of the present utility model, the movable adjustment bracket includes five connecting rods that are movably connected in sequence from top to bottom, namely the first connecting rod, the second connecting rod, the third connecting rod, the fourth connecting rod, and the fifth connecting rod; universal ball grooves are provided on the top surface of the connecting block, the lower end and the upper end of the second connecting rod, and the lower end and the upper end of the fourth connecting rod. Universal balls are provided at the lower end and the upper end of the first connecting rod, the lower end and the upper end of the third connecting rod, and the lower end of the fifth connecting rod. The universal ball at the lower end of the first connecting rod is installed in the universal ball groove on the top of the abdominal wall fitting plate, the universal ball at the upper end of the first connecting rod is installed in the universal ball groove at the lower end of the second connecting rod, the universal ball at the lower end of the third connecting rod is installed in the universal ball groove at the upper end of the second connecting rod, the universal ball at the upper end of the third connecting rod is installed in the universal ball groove at the lower end of the fourth connecting rod, and the universal ball at the lower end of the fifth connecting rod is installed in the universal ball groove at the upper end of the fourth connecting rod. The fixture is fixedly installed at the upper end of the fifth connecting rod. With this structure, through the cooperation between each universal ball and the corresponding universal ball groove, the first connecting rod can rotate and swing freely around the connecting block, the second connecting rod can rotate and swing freely around the upper end of the first connecting rod, the third connecting rod can rotate and swing freely around the upper end of the second connecting rod, the fourth connecting rod can rotate and swing freely around the upper end of the third connecting rod, and the fifth connecting rod can rotate and swing freely around the upper end of the third connecting rod, thereby realizing the adjustment of the orientation and tilt angle position of the fixture and the dilatation sheath tube thereon.
[0015] Compared with the prior art, the present utility model has the following advantages:
[0016] This dilatation sheath fixing device can effectively fix the dilatation sheath, and is applicable to fixing dilatation sheaths at different orientations and inclination angles, which can avoid problems such as displacement and falling off during the entry and exit of surgical instruments, facilitate the smooth progress of surgical treatment, and reduce the workload of surgeons and assistants. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 is a schematic structural diagram of the first embodiment of the preferred embodiment of the present invention.
[0018] Figure 2 is a schematic structural diagram of the second embodiment of the preferred embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0019] Embodiment 1
[0020] As Figure 1 shown, this percutaneous biliary puncture and fistula dilatation sheath fixing device includes an abdominal wall fitting plate 1, a movable adjustment bracket 2, and a clamp 3 for clamping the dilatation sheath 50; an adhesive layer 11 is provided on the bottom surface of the abdominal wall fitting plate 1, and a connecting block 12 is provided on the top surface of the abdominal wall fitting plate 1; the movable adjustment bracket 2 includes a plurality of connecting rods movably connected in sequence from top to bottom, the lower end of the lowermost connecting rod is installed on the connecting block 12, and the clamp 3 is installed on the upper end of the uppermost connecting rod.
[0021] In this embodiment, the abdominal wall fitting plate 1 is made of silicone, and each connecting rod of the movable adjustment bracket and the clamp 3 are made of medical plastics.
[0022] In this embodiment, the movable adjustment bracket 2 includes three connecting rods, which are the first connecting rod 21, the second connecting rod 22, and the third connecting rod 23 from bottom to top; universal ball grooves 201 are provided on the top surface of the connecting block 12, the lower and upper ends of the second connecting rod 22, and the bottom surface of the clamp 3, and universal balls 202 are provided at the lower and upper ends of the first connecting rod 21 and the lower end of the third connecting rod 23. The universal ball 202 at the lower end of the first connecting rod 21 is installed in the universal ball groove 201 on the top surface of the connecting block 12, the universal ball 202 at the upper end of the first connecting rod 21 is installed in the universal ball groove 201 at the lower end of the second connecting rod 22, the universal ball 202 at the lower end of the third connecting rod 23 is installed in the universal ball groove 201 at the upper end of the second connecting rod 22, and the universal ball 202 at the upper end of the third connecting rod 23 is installed in the universal ball groove 201 at the bottom of the clamp 3. With this structure, through the cooperation between each universal ball 202 and the corresponding universal ball groove 201, the first connecting rod 21 can be horizontally rotated and swung up and down around the connecting block 12, the second connecting rod 22 can be horizontally rotated and swung up and down around the upper end of the first connecting rod 21, and the third connecting rod 23 can be horizontally rotated and swung up and down around the upper end of the second connecting rod 22, thereby realizing the adjustment of the orientation and tilt angle position of the clamp 3 and the dilatation sheath 50 thereon.
[0023] The following briefly describes the usage method of this dilatation sheath fixing device:
[0024] During the percutaneous transhepatic biliary drainage (PTBD) procedure, after indwelling a gastric tube and a urinary catheter for the patient, performing general anesthesia with tracheal intubation and disinfecting the operative area, the target bile duct is punctured under the real-time guidance of DSA and B-ultrasound. After aspirating bile, angiography is performed to confirm entry into the target bile duct. The condition of the bile duct is observed, and then a disposable biliary dilator is slowly and gently advanced along the guide wire into the intrahepatic bile duct, gradually dilating the fistula tract from 8F to 14 - 18F, and then the dilatation sheath 50 is inserted. According to the position of the dilatation sheath 50, the abdominal wall attaching plate 1 of the above dilatation sheath 50 fixing device is attached to the corresponding position on the patient's abdominal wall through its adhesive layer 11, and then the relative positions between the connecting rods of the movable adjustment bracket 2 are adjusted to change the height position and tilt angle of the clamp 3, so that the clamp 3 is in a position where it can clamp the dilatation sheath 50, facilitating the clamp 3 to clamp and fix the dilatation sheath 50, enabling the dilatation sheath 50 to always maintain a certain tilt angle and orientation position during the operation; subsequently, the original super-stiff guide wire is retained, the tail end of the guide wire is passed through the working channel inside the rigid choledochoscope, and the choledochoscope is slowly inserted along the guide wire while opening the water pressure, and the rigid choledochoscope is advanced into the sheath along the guide wire to explore the bile duct.
[0025] Embodiment Two
[0026] Reference Figure 2, under the condition that other parts are the same as those in the first embodiment, the difference lies in that: in this embodiment, the movable adjustment bracket 2 includes two connecting rods, namely the first connecting rod 21 and the second connecting rod 22 from bottom to top; a universal ball groove 121 is provided on the top surface of the connecting block 12, and a universal ball 211 is provided at the lower end of the first connecting rod 21. The universal ball 211 is installed in the universal ball groove 121; the lower end of the second connecting rod 22 is rotatably connected to the upper end of the first connecting rod 21 through a first pin shaft 24. The first pin shaft 24 is fixedly installed at the upper end of the first connecting rod 21. A first through hole 221 is provided at the lower end of the second connecting rod 22. The lower end of the second connecting rod 22 is sleeved on the first pin shaft 24 through the first through hole 221. A first friction sleeve 25 is installed on the first pin shaft 24, and the first friction sleeve 25 is in close contact with the inner wall of the first through hole 221; the fixture 3 is rotatably connected to the upper end of the second connecting rod 22 through a second pin shaft 26. The second pin shaft 26 is fixedly installed on the fixture 3. The second pin shaft 26 is parallel to the first pin shaft 24. A second through hole 222 is provided at the upper end of the second connecting rod 22. The upper end of the second connecting rod 22 is sleeved on the second pin shaft 26 through the second through hole 222. A second friction sleeve 27 is installed on the second pin shaft 26, and the second friction sleeve 27 is in close contact with the inner wall of the second through hole 222. With this structure, through the cooperation between the universal ball 211 and the universal ball groove 121, the first connecting rod 21 can be horizontally rotated and swung up and down around the connecting block 12; the second connecting rod 22 can swing up and down relative to the first connecting rod 21 around the first pin shaft 24 to change the included angle between the second connecting rod 22 and the first connecting rod 21. The first friction sleeve 25 is used to fix the angular position turned by the second connecting rod 22 and plays a role in positioning the second connecting rod 22; the fixture 3 can swing up and down relative to the second connecting rod 22 around the second pin shaft 26 to change the included angle between the fixture 3 and the second connecting rod 22. The second friction sleeve 27 is used to fix the angular position turned by the fixture 3 and plays a role in positioning the fixture 3, thereby realizing the adjustment of the orientation and inclination angle position of the fixture 3 and the dilatation sheath 50 thereon.
[0027] In addition, it should be noted that for the specific embodiments described in this specification, the names of their respective parts and the like can be different. Any equivalent or simple changes made according to the structure, features, and principles of the inventive concept of the present utility model are included in the protection scope of the patent of the present utility model. Those skilled in the technical field to which the present utility model belongs can make various modifications, supplements, or use similar methods to replace the specific embodiments described, as long as they do not deviate from the structure of the present utility model or exceed the scope defined by the claims of this patent, they should all fall within the protection scope of the present utility model.
Claims
1. A fixing device for a percutaneous biliary puncture and fistula dilation sheath tube, characterized in that: It includes an abdominal wall attaching plate, a movable adjusting bracket, and a fixture for clamping the dilation sheath tube; an adhesive layer is provided on the bottom surface of the abdominal wall attaching plate, and a connecting block is provided on the top surface of the abdominal wall attaching plate; the movable adjusting bracket includes a plurality of connecting rods movably connected in sequence from top to bottom, the lower end of the lowermost connecting rod is installed on the connecting block, and the fixture is installed at the upper end of the uppermost connecting rod.
2. The dilatation sheath fixing device for percutaneous biliary tract puncture and fistulation according to claim 1, characterized in that: The abdominal wall attaching plate is made of medical-grade silicone or medical-grade plastic.
3. The dilatation sheath fixing device for percutaneous transhepatic biliary puncture and fistulation according to claim 1, characterized in that: Each connecting rod of the movable adjusting bracket and the fixture are both made of medical-grade plastic.
4. The dilatation sheath fixing device for percutaneous biliary tract puncture and fistulation according to claim 1, characterized in that: The adhesive layer uses biological glue.
5. A dilatation sheath fixing device for percutaneous biliary puncture and fistulation according to any one of claims 1-4, characterized in that: The movable adjusting bracket includes two connecting rods, which are the first connecting rod and the second connecting rod from bottom to top respectively; a universal ball groove is provided on the top surface of the connecting block, a universal ball is provided at the lower end of the first connecting rod, and the universal ball is installed in the universal ball groove; the lower end of the second connecting rod is rotatably connected to the upper end of the first connecting rod through a first pin shaft, and the fixture is rotatably connected to the upper end of the second connecting rod through a second pin shaft, and the second pin shaft is parallel to the first pin shaft.
6. The dilatation sheath fixing device for percutaneous biliary tract puncture and fistulation according to claim 5, wherein: The first pin shaft is fixedly installed at the upper end of the first connecting rod, a first through hole is provided at the lower end of the second connecting rod, the lower end of the second connecting rod is sleeved on the first pin shaft through the first through hole, a first friction sleeve is installed on the first pin shaft, and the first friction sleeve is in close contact with the inner wall of the first through hole; the second pin shaft is fixedly installed on the fixture, a second through hole is provided at the upper end of the second connecting rod, the upper end of the second connecting rod is sleeved on the second pin shaft through the second through hole, a second friction sleeve is installed on the second pin shaft, and the second friction sleeve is in close contact with the inner wall of the second through hole.
7. A fixing device for a dilatation sheath tube for percutaneous biliary tract puncture and fistulation according to any one of claims 1-4, characterized in that: The movable adjusting bracket includes three connecting rods, which are the first connecting rod, the second connecting rod, and the third connecting rod from bottom to top respectively; universal ball grooves are provided on the top surface of the connecting block, the lower end and the upper end of the second connecting rod, and the bottom of the fixture; universal balls are provided at the lower end and the upper end of the first connecting rod, the lower end and the upper end of the third connecting rod; the universal ball at the lower end of the first connecting rod is installed in the universal ball groove of the connecting block, the universal ball at the upper end of the first connecting rod is installed in the universal ball groove at the lower end of the second connecting rod, the universal ball at the lower end of the third connecting rod is installed in the universal ball groove at the upper end of the second connecting rod, and the universal ball at the upper end of the third connecting rod is installed in the universal ball groove at the bottom of the fixture.
8. A dilatation sheath fixing device for percutaneous biliary tract puncture and fistulation according to any one of claims 1-4, characterized in that: The movable adjustment bracket includes five connecting rods that are movably connected in sequence from top to bottom, namely a first connecting rod, a second connecting rod, a third connecting rod, a fourth connecting rod, and a fifth connecting rod; universal ball grooves are provided on the top surface of the connecting block, the lower end and the upper end of the second connecting rod, and the lower end and the upper end of the fourth connecting rod. Universal balls are provided at the lower end and the upper end of the first connecting rod, the lower end and the upper end of the third connecting rod, and the lower end of the fifth connecting rod. The universal ball at the lower end of the first connecting rod is installed in the universal ball groove at the top of the abdominal wall attaching plate, the universal ball at the upper end of the first connecting rod is installed in the universal ball groove at the lower end of the second connecting rod, the universal ball at the lower end of the third connecting rod is installed in the universal ball groove at the upper end of the second connecting rod, the universal ball at the upper end of the third connecting rod is installed in the universal ball groove at the lower end of the fourth connecting rod, and the universal ball at the lower end of the fifth connecting rod is installed in the universal ball groove at the upper end of the fourth connecting rod. The clamp is fixedly installed at the upper end of the fifth connecting rod.