Hemostatic clip placement auxiliary device for gastrointestinal surgery

Abstract

The invention relates to the technical field of medical instruments, and discloses a gastrointestinal operation hemostatic clip placement auxiliary device which comprises a traction rod, a first sliding groove is formed in the side wall of the traction rod, an opening assembly is slidably connected to the side wall of the first sliding groove, and a first moving assembly is slidably connected in the first sliding groove and a second sliding groove; the first moving assembly and one end of a second pull rod are fixedly installed, the other end of the second pull rod and a second moving assembly are fixedly installed, a rotating assembly is rotationally installed on the side wall of the traction rod, and the bottom of the rotating assembly is in threaded connection with the second moving assembly. A first moving ring moves up and down in a first sliding groove of a traction rod, then a first rotating plate and a second rotating plate are driven to rotate in a hinged mode to achieve the distraction action, a clear operation visual field is provided for a doctor, the traction rod can conveniently and accurately place a hemostatic clip to a bleeding part, and the problems that an existing device is insufficient in distraction function and the visual field is blocked are effectively solved; and the operation difficulty and risk are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to a hemostatic clip placement auxiliary device for gastrointestinal surgery. Background Art

[0002] Existing hemostatic clip placement assist devices are mainly used in gastrointestinal surgery to assist doctors in accurately placing hemostatic clips on bleeding blood vessels or tissues. Through the structural design of the device, doctors can manipulate the hemostatic clips to clamp tissues or blood vessels to stop bleeding.

[0003] However, during gastrointestinal surgery, the surgical site is often surrounded by fat and tissue that obstruct the surgeon's vision, making it difficult for the surgeon to clearly see the bleeding blood vessels or tissue, thus affecting the accurate placement of the hemostatic clip. Existing auxiliary devices may lack effective expansion structures or have unreasonable expansion structure designs, failing to effectively expand these tissues that block the surgeon's view. This results in an unclear field of view for the surgeon during the operation, increasing the difficulty and risk of the surgery.

[0004] In addition, during operation, the existing device may lack effective damping control in the transmission structure, making it difficult for doctors to accurately control the degree and speed of expansion when operating the device, and it is easy for doctors to move too quickly or too violently. This may not only cause additional damage to the tissues at the surgical site, but also affect the accuracy of the hemostatic clip placement, thereby affecting the hemostatic effect and the safety of the operation.

[0005] Therefore, it is necessary to provide a gastrointestinal surgery hemostatic clip placement auxiliary device to solve the above problems. Summary of the Invention

[0006] The purpose of the present invention is to provide a technical solution to solve the problems in the prior art raised in the above background technology.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] The hemostatic clip placement auxiliary device for gastrointestinal surgery comprises a traction rod, the interior of the traction rod is slidably connected to a first pull rod, one end of the first pull rod is installed with a thumb ring, the other end of the first pull rod is installed with a hemostatic clip pull head, one end of the traction rod is fixedly installed with the hemostatic clip, and the other end of the traction rod is fixedly connected to index finger rings on both sides, the side wall of the traction rod is provided with a first sliding groove, the side wall of the first sliding groove is slidably connected to a spreading assembly, and the spreading assembly comprises a first rotating plate, a second rotating plate and a silicone strip, the first rotating plate is hinged to the second rotating plate, the surfaces of the first rotating plate and the second rotating plate are provided with a dovetail groove, the bottom of the silicone strip is connected to the dovetail groove with a mortise and tenon joint, the end of the first rotating plate is hinged to the traction rod, and the end of the second rotating plate is hinged to the first moving assembly;

[0009] The first moving assembly is slidably connected in the first sliding groove and the second sliding groove, and one end of the second pull rod is fixedly installed with the first moving assembly;

[0010] The other end of the second pull rod is fixedly installed with the second moving assembly, and the side wall of the traction rod is rotatably installed with a rotating assembly, and the bottom of the rotating assembly is threadedly connected with the second moving assembly.

[0011] Preferably, the surface of the silica gel strip is arc-shaped, and the inside of the silica gel strip is hollow and filled with air.

[0012] Preferably, the first moving assembly comprises a first moving ring, a second hinged groove, a first sliding block, a sliding cylinder and a mounting block, the second hinged groove is arranged on the side wall of the moving ring, the first moving ring is slidably connected on the first sliding groove, the inner side of the first moving ring is fixedly connected with the sliding cylinder through the first sliding block, the first sliding block is slidably connected in the second sliding groove, and the inner two sides of the sliding cylinder are fixedly connected with mounting blocks, and the mounting blocks are fixedly installed with one end of the second pull rod.

[0013] Preferably, a first hinged groove is arranged on one side of the first sliding groove, the end of the first rotating plate is rotatably connected with the inside of the first hinged groove, the second hinged groove is arranged along one circle of the first moving ring at equal angles, and the ends of the second rotating plate are rotatably connected with the inside of the second hinged groove.

[0014] Preferably, the second moving assembly comprises a second moving ring, a second sliding block and a third sliding groove, the second sliding block is fixedly connected on the side wall of the first moving ring, the inside of the traction rod is arranged with a third sliding groove, the second sliding block is slidably connected in the third sliding groove, the other end of the second pull rod is fixedly connected with the bottom surface of the first moving ring, and the inside of the first moving ring is arranged with a threaded hole.

[0015] Preferably, the rotating assembly comprises a rotating part, a driving part and a damping part, the rotating part is rotatably installed on the side wall of the traction rod, the driving part is fixedly connected on the bottom surface of the rotating part, the damping part is fixedly connected on the top surface of the rotating part, and the driving part is threadedly connected with the threaded hole.

[0016] Preferably, the rotating part comprises a knob, a connecting plate and a rotating cylinder, the top of the traction rod is arranged with a rotating groove, the knob is fixedly connected with the side wall of the rotating cylinder through the connecting plate, the rotating cylinder is rotatably connected in the inside of the traction rod, the knob is rotatably connected on the side wall of the traction rod, and the connecting plate is slidably connected in the rotating groove.

[0017] Preferably, the driving part comprises a threaded cylinder, the threaded cylinder is fixedly connected on the bottom surface of the rotating cylinder, and the side wall of the threaded cylinder is threadedly connected with the threaded hole.

[0018] Preferably, the damping component includes a swivel, a mounting groove, a spring, a bullet and an annular wave groove. The swivel is fixedly connected to the top surface of the drum. A mounting groove is provided inside the side wall of the swivel. The spring is installed in the mounting groove. The bullet is slidably installed in the mounting groove. An annular wave groove is provided on the inner side wall of the traction rod. The end of the bullet is in contact with the annular wave groove.

[0019] Preferably, the interiors of the rotating ring, the rotating cylinder and the threaded cylinder are all provided with through grooves for the first pull rod to pass through.

[0020] Technical effects and advantages of the present invention: The gastrointestinal surgery hemostatic clip placement auxiliary device proposed by the present invention has the following advantages compared with the prior art:

[0021] 1. The expansion assembly of the present invention comprises a first rotating plate, a second rotating plate, and a silicone strip. Rotating the knob drives the threaded barrel to rotate, causing the first movable ring to move up and down in the first sliding groove of the traction rod, thereby driving the first and second rotating plates to hinge and rotate to achieve the expansion action. The silicone strip has a curved surface and a hollow, air-filled interior, making it elastic and able to gently expand fat and tissue that obstructs the view, providing the doctor with a clear surgical field of view and facilitating the traction rod to accurately place the hemostatic clip at the bleeding site. This effectively solves the problems of insufficient expansion function and obstructed field of view of existing devices, reducing the difficulty and risk of surgery.

[0022] 2. The damping component of the rotating assembly in this invention, through the coordination of a swivel, spring, bullet, and annular wave groove, produces a damping effect when the knob is turned, allowing the surgeon to more smoothly control the degree and speed of distraction. Furthermore, the threaded transmission structure and the sliding of the first slider in the second groove ensure the stability of the movement of the first movable ring, enabling precise control of the distraction assembly's movement. This avoids the overly rapid or abrupt movements of existing devices, reduces additional damage to the surgical site, improves the accuracy of hemostatic clip placement, and ensures hemostatic effectiveness and surgical safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic structural diagram of the gastrointestinal surgery hemostatic clip placement auxiliary device of the present invention;

[0024] Figure 2 This is a schematic structural diagram of the installation of the expansion assembly, the first moving assembly and the traction rod of the present invention;

[0025] Figure 3 Schematic diagram of the structure of the first moving assembly of the present invention;

[0026] Figure 4 This is a schematic diagram of the structure of the support assembly of the present invention;

[0027] Figure 5It is a schematic structural diagram of a bottom cross-section of a drawbar of the present invention;

[0028] Figure 6 It is a schematic structural diagram of a top cross-section of a drawbar of the present invention;

[0029] Figure 7 For the present invention Figure 6 Schematic diagram of the structure enlarged at point A.

[0030] In the picture:

[0031] 1. Traction rod; 11. First chute; 12. Second chute; 13. First hinge slot;

[0032] 2. Spreading assembly; 21. First rotating plate; 22. Second rotating plate; 23. Dovetail groove; 24. Silicone strip;

[0033] 3. First moving assembly; 31. First moving ring; 32. Second hinge groove; 33. First slider; 34. Slide; 35. Mounting block;

[0034] 4. Rotating assembly; 41. Knob; 42. Connecting plate; 43. Rotating cylinder; 44. Damping component; 441. Swivel; 442. Mounting slot; 443. Spring; 444. Bullet; 445. Annular wave groove; 45. Threaded cylinder;

[0035] 5. Index finger ring;

[0036] 6. Thumb ring;

[0037] 7. First pull rod;

[0038] 8. Hemostatic clamp pull head;

[0039] 9. Second pull rod;

[0040] 10. Second movable assembly; 101. Second movable ring; 102. Second slider; 103. Third slide groove. DETAILED DESCRIPTION

[0041] The subject matter described herein will now be discussed with reference to exemplary embodiments. It should be understood that these embodiments are discussed solely to enable those skilled in the art to better understand and implement the subject matter described herein, and that the functions and arrangements of the elements discussed may be varied without departing from the scope of this specification. Various examples may omit, substitute, or add various processes or components as needed. Furthermore, features described for some examples may be combined in other examples.

[0042] The invention provides Figures 1 to 7As shown, a gastrointestinal surgery hemostatic clamp placement auxiliary device includes a traction rod 1, a first pull rod 7 is slidably connected inside the traction rod 1, a thumb ring 6 is installed at one end of the first pull rod 7, and a hemostatic clamp pull head 8 is installed at the other end of the first pull rod 7. A hemostatic clamp is fixedly installed at one end of the traction rod 1, and the hemostatic clamp pull head 8 provides pulling force for the hemostatic clamp, so that the hemostatic clamp clamps tissues or blood vessels to stop bleeding. The other end of the traction rod 1 is fixedly connected to index finger rings 5 ​​on both sides.

[0043] When the doctor holds the device, his thumb passes through the thumb ring 6 and his index finger passes through the index finger ring 5, using the force of his fingers to move the traction rod 1. When he needs to clamp and stop bleeding, he pulls the thumb ring 6, driving the first pull rod 7 to slide inside the traction rod 1. The hemostatic clamp pull head 8 at the other end of the first pull rod 7 moves accordingly, providing tension to the hemostatic clamp, closing the clamp arms and clamping the tissue or blood vessel, ensuring that the hemostatic clamp can be accurately applied to the bleeding site.

[0044] like Figure 2 and Figure 3 As shown, the side wall of the traction rod 1 is provided with a first sliding groove 11, and the side wall of the first sliding groove 11 is slidably connected with a support component 2, and the support component 2 includes a first rotating plate 21, a second rotating plate 22 and a silicone strip 24. The first rotating plate 21 is hinged to the second rotating plate 22, and the surfaces of the first rotating plate 21 and the second rotating plate 22 are provided with a dovetail groove 23. The bottom of the silicone strip 24 is connected to the dovetail groove 23 with mortise and tenon joints, and the surface of the silicone strip 24 is an arc surface.

[0045] The end of the first rotating plate 21 is hinged to the traction rod 1, the end of the second rotating plate 22 is hinged to the first moving component 3, the first moving component 3 is slidably connected in the first chute 11 and the second chute 12, and the first moving component 3 is fixedly installed with one end of the second pull rod 9. Specifically, Figure 3 As shown, the first moving component 3 includes a first moving ring 31, a second hinge groove 32, a first slider 33, a slide cylinder 34 and a mounting block 35. The second hinge groove 32 is opened on the side wall of the moving ring. The first moving ring 31 is slidably connected on the first slide groove 11. The inner side of the first moving ring 31 is fixedly connected to the slide cylinder 34 through the first slider 33. The first slider 33 is slidably connected in the second slide groove 12. The inner two sides of the slide cylinder 34 are respectively fixedly connected with mounting blocks 35. The mounting block 35 is fixedly installed on one end of the second pull rod 9. The traction rod 1 is located on one side of the first slide groove 11 and is provided with a first hinge groove 13. The end of the first rotating plate 21 is connected to the internal rotation of the first hinge groove 13. The second hinge groove 32 is opened at equal angles along a circle of the first moving ring 31. The ends of the second rotating plate 22 are respectively connected to the internal rotation of the second hinge groove 32.

[0046] When the screw cylinder 45 is rotated, the first movable ring 31 is driven to move up and down in the first slide groove 11 of the traction rod 1 due to the transmission effect of the thread. The first movable ring 31 is fixedly connected to the slide cylinder 34 through the first slider 33, and the first slider 33 slides in the second slide groove 12, thereby ensuring the stability of the movement of the first movable ring 31. The movement of the first movable ring 31 drives the second pull rod 9 to move through the mounting block 35. The other end of the second pull rod 9 is fixedly connected to the second movable assembly 10, and then the second movable assembly 10 slides in the third slide groove 103 inside the traction rod 1. The movable assembly plays a key role in transmission in the entire device. It converts the rotation of the rotating assembly 4 into linear movement, realizes the driving of the expansion assembly 2, and enables the expansion assembly 2 to expand or retract according to the doctor's operating intention, ensures the coordinated work between the various components of the device, and provides power transmission guarantee for the smooth progress of the surgical operation.

[0047] When the second movable assembly 10 moves up and down inside the traction rod 1, the first movable assembly 3 is driven to slide in the first slide groove 11 and the second slide groove 12 through the second pull rod 9. Since the first movable assembly 3 is hinged to the second rotating plate 22, and the first rotating plate 21 is hinged to the traction rod 1, the sliding of the first movable assembly 3 will cause the first rotating plate 21 and the second rotating plate 22 to rotate around the hinge point. When the first rotating plate 21 and the second rotating plate 22 rotate, the angle between the two changes, thereby achieving an opening or closing action. During the opening process, the curved silicone strip 24 can fit the tissue surface and gradually open the tissue as the rotating plate rotates. The opening assembly 2 can effectively open the fat, tissue, etc. that blocks the line of sight, providing the doctor with a clear surgical field of view, and facilitating the traction rod 1 to accurately place the hemostatic clamp on the bleeding blood vessel or tissue for hemostasis.

[0048] Furthermore, the interior of the silicone strip 24 is hollow and filled with air. The silicone strip 24 is filled with air and has elasticity. During the expansion process, the curved silicone strip 24 can fit the tissue surface and gradually expand the tissue as the rotating plate rotates. The elasticity and curved surface design of the silicone strip 24 reduce damage to the tissue, and the hollow air-filled structure enables it to apply force gently during expansion to avoid excessive squeezing of the tissue.

[0049] like Figure 6 As shown, the other end of the second pull rod 9 is fixedly installed with the second movable assembly 10. The second movable assembly 10 includes a second movable ring 101, a second slider 102 and a third slide groove 103. The second slider 102 is fixedly connected to the side wall of the first movable ring 31. The third slide groove 103 is opened inside the traction rod 1. The second slider 102 is slidably connected in the third slide groove 103. The other end of the second pull rod 9 is fixedly connected to the bottom surface of the first movable ring 31. The first movable ring 31 is opened inside with a threaded hole.

[0050] A rotating assembly 4 is rotatably installed on the side wall of the traction rod 1, and the bottom of the rotating assembly 4 is threadedly connected to the second movable assembly 10. Specifically, the rotating assembly 4 includes a rotating part, a driving part and a damping part 44. The rotating part is rotatably installed on the side wall of the traction rod 1, the driving part is fixedly connected to the bottom surface of the rotating part, the damping part 44 is fixedly connected to the top surface of the rotating part, and the driving part is threadedly connected to the threaded hole.

[0051] The rotating component includes a knob 41, a connecting plate 42 and a rotating drum 43. A rotating groove is opened at the top of the traction rod 1. The knob 41 is fixedly connected to the side wall of the rotating drum 43 through the connecting plate 42. The rotating drum 43 is rotatably connected inside the traction rod 1. The knob 41 is rotatably connected on the side wall of the traction rod 1. The connecting plate 42 is slidably connected in the rotating groove. The driving component includes a threaded drum 45. The threaded drum 45 is fixedly connected to the bottom surface of the rotating drum 43. The side wall of the threaded drum 45 is threadedly connected to the threaded hole.

[0052] The doctor turns the knob 41, and the knob 41 is fixedly connected to the rotating cylinder 43 through the connecting plate 42, thereby driving the rotating cylinder 43 to rotate in the rotating groove inside the traction rod 1. The threaded cylinder 45 at the bottom of the rotating cylinder 43 is threadedly connected to the threaded hole of the first movable ring 31. The rotation of the rotating cylinder 43 causes the threaded cylinder 45 to rotate synchronously. According to the principle of thread transmission, the rotation of the threaded cylinder 45 will push the first movable ring 31 to move up and down in the first slide groove 11 of the traction rod 1, so that the first movable ring 31 drives the second pull rod 9 and the second movable ring 101 to slide up and down in the first slide groove 11, thereby controlling the action of the expansion component 2 by turning the knob 41.

[0053] Further, such as Figure 7 As shown, the damping component 44 includes a swivel 441, a mounting groove 442, a spring 443, a bullet 444 and an annular wave groove 445. The swivel 441 is fixedly connected to the top surface of the rotating drum 43. The side wall of the swivel 441 is provided with a mounting groove 442. The spring 443 is installed in the mounting groove 442. The bullet 444 is slidably installed in the mounting groove 442. The inner side wall of the traction rod 1 is provided with an annular wave groove 445. The end of the bullet 444 abuts against the annular wave groove 445. The swivel 441 on the top surface of the rotating drum 43 rotates with the rotating drum 43. The spring 443 in the mounting groove 442 on the side wall of the swivel 441 pushes the bullet 444 to abut against the annular wave groove 445 on the inner side wall of the traction rod 1. When the swivel 441 rotates, the bullet 444 slides in the wavy structure of the annular wave groove 445 and is subjected to the resistance of the wavy groove, thereby generating a damping effect, making the rotation of the knob 41 more stable.

[0054] It is worth noting that a through slot for the first pull rod 7 to pass through is provided inside the rotating ring 441 , the rotating cylinder 43 and the threaded cylinder 45 , thereby providing space for the first pull rod 7 to move.

[0055] The above describes the embodiments of the present invention, but the present invention is not limited to the above specific implementation methods. The above specific implementation methods are merely illustrative and not restrictive. Ordinary technicians in this field can also make many forms under the guidance of the present invention, all of which are protected by the present invention.

Claims

1. A gastrointestinal surgery hemostatic clip placement auxiliary device, comprising a traction rod (1), wherein the interior of the traction rod (1) is slidably connected to a first pull rod (7), one end of the first pull rod (7) is installed with a thumb ring (6), the other end of the first pull rod (7) is installed with a hemostatic clip pull head (8), one end of the traction rod (1) is fixedly installed with a hemostatic clip, and the other end of the traction rod (1) is fixedly connected to index finger rings (5) on both sides, characterized in that: The side wall of the traction rod (1) is provided with a first sliding groove (11), and the side wall of the first sliding groove (11) is slidably connected to a spreading assembly (2), and the spreading assembly (2) includes a first rotating plate (21), a second rotating plate (22) and a silicone strip (24), the first rotating plate (21) and the second rotating plate (22) are hinged, and the surfaces of the first rotating plate (21) and the second rotating plate (22) are provided with a dovetail groove (23), and the bottom of the silicone strip (24) is connected to the dovetail groove (23) by mortise and tenon, the end of the first rotating plate (21) is hinged to the traction rod (1), and the end of the second rotating plate (22) is hinged to the first moving assembly (3); The first moving component (3) is slidably connected in the first sliding groove (11) and the second sliding groove (12), and the first moving component (3) is fixedly mounted on one end of the second pull rod (9); The other end of the second pull rod (9) is fixedly mounted to the second movable assembly (10), and a rotating assembly (4) is rotatably mounted on the side wall of the traction rod (1), and the bottom of the rotating assembly (4) is threadedly connected to the second movable assembly (10).

2. The gastrointestinal surgery hemostatic clip placement auxiliary device according to claim 1, characterized in that: The surface of the silicone strip (24) is an arc surface, and the interior of the silicone strip (24) is hollow and filled with air.

3. The gastrointestinal surgery hemostatic clip placement auxiliary device according to claim 1, characterized in that: The first moving assembly (3) includes a first moving ring (31), a second hinge groove (32), a first slider (33), a slide cylinder (34) and a mounting block (35), wherein the second hinge groove (32) is provided on the side wall of the moving ring, the first moving ring (31) is slidably connected on the first slide groove (11), the inner side of the first moving ring (31) is fixedly connected to the slide cylinder (34) through the first slider (33), the first slider (33) is slidably connected in the second slide groove (12), and the inner two sides of the slide cylinder (34) are respectively fixedly connected with mounting blocks (35), and the mounting block (35) is fixedly mounted to one end of the second pull rod (9).

4. The gastrointestinal surgery hemostatic clip placement auxiliary device according to claim 3, characterized in that: The traction rod (1) is provided with a first hinge groove (13) on one side of the first slide groove (11), the end of the first rotating plate (21) is connected to the inside of the first hinge groove (13) for rotation, the second hinge groove (32) is provided at equal angles along a circle of the first movable ring (31), and the ends of the second rotating plate (22) are respectively connected to the inside of the second hinge groove (32) for rotation.

5. The gastrointestinal surgery hemostatic clip placement auxiliary device according to claim 1, characterized in that: The second moving assembly (10) includes a second moving ring (101), a second slider (102) and a third slide groove (103), the second slider (102) is fixedly connected to the side wall of the first moving ring (31), the third slide groove (103) is provided inside the traction rod (1), the second slider (102) is slidably connected in the third slide groove (103), the other end of the second pull rod (9) is fixedly connected to the bottom surface of the first moving ring (31), and a threaded hole is provided inside the first moving ring (31).

6. The gastrointestinal surgery hemostatic clip placement auxiliary device according to claim 5, characterized in that: The rotating assembly (4) comprises a rotating component, a driving component and a damping component (44); the rotating component is rotatably mounted on the side wall of the traction rod (1); the driving component is fixedly connected to the bottom surface of the rotating component; the damping component (44) is fixedly connected to the top surface of the rotating component; and the driving component is threadedly connected to the threaded hole.

7. The gastrointestinal surgery hemostatic clip placement auxiliary device according to claim 6, characterized in that: The rotating component comprises a knob (41), a connecting plate (42) and a rotating drum (43); a rotating groove is provided on the top of the traction rod (1); the knob (41) is fixedly connected to the side wall of the rotating drum (43) through the connecting plate (42); the rotating drum (43) is rotatably connected inside the traction rod (1); the knob (41) is rotatably connected on the side wall of the traction rod (1); and the connecting plate (42) is slidably connected in the rotating groove.

8. The gastrointestinal surgery hemostatic clip placement auxiliary device according to claim 7, characterized in that: The driving component comprises a threaded barrel (45), the threaded barrel (45) is fixedly connected to the bottom surface of the rotating barrel (43), and the side wall of the threaded barrel (45) is threadedly connected to the threaded hole.

9. The gastrointestinal surgery hemostatic clip placement auxiliary device according to claim 8, characterized in that: The damping component (44) comprises a rotating ring (441), a mounting groove (442), a spring (443), a bullet (444) and an annular wave groove (445); the rotating ring (441) is fixedly connected to the top surface of the rotating drum (43); a mounting groove (442) is provided inside the side wall of the rotating ring (441); the spring (443) is installed in the mounting groove (442); the bullet (444) is slidably installed in the mounting groove (442); an annular wave groove (445) is provided on the inner side wall of the traction rod (1); and the end of the bullet (444) abuts against the annular wave groove (445).

10. The gastrointestinal surgery hemostatic clip placement auxiliary device according to claim 9, characterized in that: The interiors of the rotating ring (441), the rotating cylinder (43) and the threaded cylinder (45) are all provided with through slots for the first pull rod (7) to pass through.

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