Sternum dilator

Abstract

The invention relates to the technical field of medical instruments, and provides a sternum dilator. Comprising a guide plate, the guide plate is provided with a first distraction arm and a second distraction arm, and the distance between the first distraction arm and the second distraction arm is adjustable; a first limiting assembly is arranged on the first distraction arm, a second limiting assembly is arranged on the second distraction arm, and the first limiting assembly and the second limiting assembly are symmetrically arranged; a first U-shaped seat and a second U-shaped seat in the first limiting assembly can get close to each other or get away from each other in the axial direction of the first distraction arm, and the opposite ends of the first U-shaped seat and the second U-shaped seat can deform; a third U-shaped seat and a fourth U-shaped seat of the second limiting assembly can get close to or get away from each other in the axial direction of the second distraction arm, and the opposite ends of the third U-shaped seat and the fourth U-shaped seat can deform. The sternum distraction device has the advantages that elastic deformation of the flexible units can adapt to the shape of the sternum distraction position, the supporting strips on the four U-shaped seats can deform after being subjected to acting force of sternum, and an operation can be conducted conveniently.

Description

Technical Field

[0001] The invention relates to the technical field of medical devices, and in particular to a sternal spreader. Background Art

[0002] Median sternotomy is a classic surgical approach in cardiothoracic surgery and can be used for many lower neck and intrathoracic organ surgeries. Partial and complete median sternotomy can be used for lower neck surgeries including tracheal resection, thyroid nodules and parathyroid adenomas, lower neck lymph node dissection, removal of cervical esophageal tumors, and cleaning of bilateral chest empyema. Due to its excellent exposure to the heart and great vessels, the median sternotomy has become the gold standard incision for many cardiac surgeries, especially those requiring extracorporeal circulation. The median sternotomy can also expose the bilateral lungs, hilum, and pleural cavity, and can be used for lobectomy, bilateral lung volume reduction, bilateral lung metastatic tumor resection, and lung transplantation. For re-lobectomy, especially pneumonectomy, if the hilum adhesions are mild, the median sternotomy can also be used.

[0003] Existing sternal spreaders have a single function and can only be used to support the sternum. Moreover, most sternal spreaders only have flexible parts on the spreader arms to adapt to the shape of the sternum, which cannot meet the use requirements.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The purpose of the present invention is to provide a sternal spreader to solve the technical problems existing in the prior art.

[0006] To achieve the above object, the technical solution adopted by the present invention is: a sternal spreader, comprising: a guide plate, on which a first spreader arm and a second spreader arm are arranged, and the distance between the first spreader arm and the second spreader arm is adjustable;

[0007] The first opening arm is provided with a first limiting assembly, the second opening arm is provided with a second limiting assembly, and the first limiting assembly and the second limiting assembly are symmetrically arranged;

[0008] The first U-shaped seat and the second U-shaped seat in the first limiting assembly can move closer to or farther from each other along the axial direction of the first spreading arm, and the opposite ends of the first U-shaped seat and the second U-shaped seat can be deformed;

[0009] The third U-shaped seat and the fourth U-shaped seat of the second limiting assembly can approach or move away from each other along the axial direction of the second spreading arm, and the opposite ends of the third U-shaped seat and the fourth U-shaped seat can be deformed.

[0010] In an optional embodiment, the first U-shaped seat and the second U-shaped seat can move along the first spreading arm body of the first spreading arm;

[0011] The first U-shaped seat and the second U-shaped seat each include a movable base, each of the movable bases is provided with a U-shaped plate, and the U-shaped opening of the U-shaped plate is arranged in a direction away from the second spreading arm;

[0012] A plurality of parallel support bars extending along the axial direction of the first spreading arm body are arranged on the bottom plate of each U-shaped plate, and each of the support bars has a certain elasticity and can be deformed;

[0013] The support bars on the first U-shaped seat and the second U-shaped seat are arranged facing each other, and the opposite ends do not contact each other.

[0014] In an optional embodiment, the third U-shaped seat and the fourth U-shaped seat can move along the second spreading arm body of the second spreading arm;

[0015] The third U-shaped seat and the fourth U-shaped seat each include a movable base, each of the movable bases is provided with a U-shaped plate, and the U-shaped opening of the U-shaped plate is arranged in a direction away from the first spreading arm;

[0016] A plurality of parallel support bars extending along the axial direction of the second spreading arm body are arranged on the bottom plate of each U-shaped plate, and each of the support bars has a certain elasticity and can be deformed;

[0017] The support bars on the third U-shaped seat and the fourth U-shaped seat are arranged facing each other, and the opposite ends do not contact each other.

[0018] In an optional embodiment, a flexible polymer component extending from the front end of the first U-shaped seat to the rear end of the second U-shaped seat is disposed in the first U-shaped seat and the second U-shaped seat;

[0019] A flexible polymer component extending from the front end of the third U-shaped seat to the rear end of the fourth U-shaped seat is arranged in the third U-shaped seat and the fourth U-shaped seat.

[0020] In an optional embodiment, the flexible polymer component is composed of a plurality of flexible units connected together, and a drug coating is disposed on the surface of each of the flexible units.

[0021] In an optional embodiment, the surface of the flexible polymer component without drug coating is adhered to a gasket component, and the gasket component is composed of a plurality of gasket units, and the size of the gasket unit is the same as the size of the flexible unit.

[0022] In an optional embodiment, the gasket assembly fits the bottom plate of the U-shaped plate of the first U-shaped seat and the second U-shaped seat and the plurality of support bars; the gasket assembly fits the bottom plate of the U-shaped plate of the third U-shaped seat and the fourth U-shaped seat and the plurality of support bars.

[0023] In an optional embodiment, a plurality of suture line limiting components are provided on the surface of the first spreading arm body away from the first U-shaped seat and the second U-shaped seat;

[0024] A plurality of suture line limiting components are arranged on the surface of the second spreading arm body away from the third U-shaped seat and the fourth U-shaped seat;

[0025] The number of the suture line limiting components on the first expansion arm body and the suture line limiting components on the second expansion arm body are the same and are arranged in a mirror image.

[0026] In an optional embodiment, the suture thread limiting assembly includes a first thread groove, a second thread groove and a third thread groove; the starting ends of the first thread groove and the second thread groove face the outside of the spreader, the end of the third thread groove faces the inside of the spreader, and the ends of the first thread groove and the second thread groove are connected to the starting end of the third thread groove;

[0027] The first wire groove and the second wire groove are symmetrical about the center line of the third wire groove.

[0028] In an optional embodiment, a rotatable first pressing wheel is disposed in the first wire groove, and a rotatable second pressing wheel is disposed in the second wire groove;

[0029] The first pressing wheel and the second pressing wheel are arranged facing each other and rotate in opposite directions; the surfaces of the first pressing wheel and the second pressing wheel are both provided with pressing teeth.

[0030] The beneficial effects of the present invention are:

[0031] (1) The elastic deformation of the flexible unit and the gasket unit of the present invention can better adapt to the shape of the sternal expansion part. In order to further adapt to the shape of the sternal expansion part of different patients during surgery, the distance between each group of U-shaped seats is adjustable, and the multiple support bars on the four U-shaped seats can also undergo adaptive deformation after being subjected to the force of the sternum, which is convenient for the operation. The support bars on each group of U-shaped seats are arranged facing each other, and the opposite ends do not touch each other, which can expand the deformation space.

[0032] (2) The present invention utilizes two expansion arms, suture limiting components on the two expansion arms, and sutures to expand the tissue opening of the surgical site from both sides to a size suitable for surgery, thereby enriching the function of the sternal expander. In addition, a drug coating is provided on the surface of the flexible unit, which is beneficial to the patient's postoperative recovery. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0034] Figure 1 The overall structure of the sternum spreader provided by one embodiment of the present invention is schematically shown. Figure 1 .

[0035] Figure 2 for Figure 1 A schematic diagram of the enlarged local structure at point A in the middle.

[0036] Figure 3 for Figure 1 A magnified schematic diagram of the local structure at point B in the middle.

[0037] Figure 4 The overall structure of the sternum spreader provided by one embodiment of the present invention is schematically shown. Figure 2 .

[0038] Figure 5 The overall structure of the sternum spreader provided by one embodiment of the present invention is schematically shown. Figure 3 .

[0039] Figure 6 A bottom view of a sternal spreader provided in one embodiment of the present invention.

[0040] Figure 7 for Figure 6 Schematic diagram of the enlarged local structure at C in the middle (suture line).

[0041] Among them, the accompanying drawings are marked as follows:

[0042] 1-first opening arm, 11-first base, 12-first opening arm body; 2-second opening arm, 21-second base, 22-second opening arm body, 23-limiting hole, 24-first guide groove, 25-second guide groove; 3-guide plate; 4-locking assembly, 41-locker, 42-handle; 5-first limiting assembly, 51-first U-shaped seat, 511-first support bar, 512-second support bar, 52-second U U-shaped seat, 521-third support bar, 522-fourth support bar; 6-second limiting assembly, 61-third U-shaped seat, 62-fourth U-shaped seat, 621-movable base, 622-U-shaped plate, 623-guide groove; 7-flexible polymer assembly, 71-flexible unit; 8-gasket assembly; 9-suture line limiting assembly, 91-first wire groove, 92-second wire groove, 93-third wire groove, 94-first pressure wheel, 95-second pressure wheel. DETAILED DESCRIPTION

[0043] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0044] It should be noted that when a component is referred to as being "fixed on" or "disposed on" another component, it may be directly or indirectly located on the other component. When a component is referred to as being "connected to" another component, it may be directly or indirectly connected to the other component. The directions or positions indicated by the terms "upper", "lower", "left", "right", "front", "back", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. are based on the directions or positions shown in the accompanying drawings and are only for the convenience of description and cannot be understood as limitations on the present technical solution. The terms "first" and "second" are only used for the convenience of description and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features. "Multiple" means two or more, and "several" means any number including one, unless otherwise clearly and specifically defined.

[0045] Please see attached Figure 1-7 The purpose of this embodiment is to provide a sternal spreader, including: a guide plate 3, on which a first spread arm 1 and a second spread arm 2 are arranged, and the distance between the first spread arm 1 and the second spread arm 2 is adjustable. Specifically, the first spread arm 1 includes a first base 11, and a first spread arm body 12 connected to the first base 11; the second spread arm 2 includes a second base 21, and a second spread arm body 22 connected to the second base 12. In this embodiment, the first base 11 is fixedly connected to one end of the guide plate 3, and the second base 21 is sleeved on the guide plate 3, and the second base 21 can move along the guide plate 3. Adjust the distance between the two spread arms to complete different degrees of expansion of the patient's chest. In a preferred embodiment, the first base 1 can also be slidably sleeved on the guide plate 3 to further improve the convenience of adjusting the distance between the two spread arms. A locking assembly 4 is provided on the second base 12, and the locking assembly 4 includes a handle 42 and a locker 41. After the position of the second spreading arm 2 is determined, the second base 21 is fixed to the guide plate 3 by using the locking assembly 4. It should be noted that the locking assembly 4 is a prior art, and technicians in this field can select it according to design requirements, which will not be described in detail.

[0046] Furthermore, a first limiting assembly 5 is provided on the first expansion arm 1, and the first limiting assembly 5 includes a first U-shaped seat 51 and a second U-shaped seat 52. The first U-shaped seat 51 and the second U-shaped seat 52 in the first limiting assembly 5 can be close to or away from each other along the axial direction of the first expansion arm 1 (to meet the expansion requirements of different patients), and the opposite ends of the first U-shaped seat 51 and the second U-shaped seat 52 can be deformed. Specifically, the first U-shaped seat 51 and the second U-shaped seat 52 can move along the first expansion arm body 12 of the first expansion arm 1, and the first U-shaped seat 51 and the second U-shaped seat 52 each include a movable base, and each movable base is provided with a U-shaped plate, and the U-shaped opening of the U-shaped plate is arranged in a direction away from the second expansion arm 2.

[0047] The first opening arm body 12 is provided with a first guide rail groove and a second guide rail groove, and the guide grooves on both sides of the movable base in the first U-shaped seat 51 and the second U-shaped seat 52 are slidably connected with the corresponding guide rail grooves. After adjusting the distance between the first U-shaped seat 51 and the second U-shaped seat 52, the first U-shaped seat 51 and the second U-shaped seat 52 can be fixed respectively. The first opening arm body 12 is provided with a plurality of limiting holes, and the plurality of limiting holes are used to limit the first U-shaped seat 51 and the second U-shaped seat 52.

[0048] It is worth mentioning that the bottom plate of each U-shaped plate is provided with a plurality of parallel support bars extending along the axial direction of the first open arm body 12, and each support bar has a certain elasticity and can be deformed. Figure 3 In this embodiment, the first U-shaped seat 51 is provided with a first support bar 511 and a second support bar 512. The first support bar 511 and the second support bar 512 extend from the closed end of the bottom plate of the U-shaped plate in the first U-shaped seat 51 in a direction away from the guide plate 3. The second U-shaped seat 52 is provided with a third support bar 521 and a fourth support bar 522. The third support bar 521 and the fourth support bar 522 extend from the closed end of the bottom plate of the U-shaped plate in the second U-shaped seat 52 in a direction close to the guide plate 3. The support bars on the first U-shaped seat 51 and the second U-shaped seat 52 are arranged facing each other, and the opposite ends do not contact, that is, the first support bar 511 does not contact the third support bar 521, and the second support bar 512 does not contact the fourth support bar 622, thereby expanding the deformation space.

[0049] Furthermore, a second limit assembly 6 is provided on the second spread arm 2, and the first limit assembly 5 and the second limit assembly 6 are symmetrically arranged. The third U-shaped seat 61 and the fourth U-shaped seat 62 of the second limit assembly 6 can be close to or away from each other along the axial direction of the second spread arm 2 (to adapt to the spread requirements of different patients), and the opposite ends of the third U-shaped seat 61 and the fourth U-shaped seat 62 can be deformed. The third U-shaped seat 61 and the fourth U-shaped seat 62 can move along the second spread arm body 22 of the second spread arm 2. The third U-shaped seat 61 and the fourth U-shaped seat 62 each include a movable base, each of which is provided with a U-shaped plate, and the U-shaped opening of the U-shaped plate is arranged in a direction away from the first spread arm 1.

[0050] The second opening arm body 22 is provided with a first guide groove 24 and a second guide groove 25, and the guide grooves 623 on both sides of the movable base 621 in the third U-shaped seat 61 and the fourth U-shaped seat 62 cooperate with the corresponding guide grooves for sliding connection, and after adjusting the distance between the third U-shaped seat 61 and the fourth U-shaped seat 62, the third U-shaped seat 61 and the fourth U-shaped seat 62 can be fixed respectively. The second opening arm body 22 is provided with a plurality of limiting holes 23, and the plurality of limiting holes 23 are used to limit the third U-shaped seat 61 and the fourth U-shaped seat 62.

[0051] It is worth mentioning that a plurality of parallel support bars extending along the axial direction of the second open arm body 22 are arranged on the bottom plate of each U-shaped plate, and each support bar has a certain elastic deformation. The third U-shaped seat 61 is provided with a first support bar, a second support bar, a first support bar, and a second support bar extending from the closed end of the bottom plate of the U-shaped plate in the third U-shaped seat 61 in a direction away from the guide plate 3. The fourth U-shaped seat 62 is provided with a third support bar, a fourth support bar, a third support bar, and a fourth support bar extending from the closed end of the bottom plate of the U-shaped plate 622 in the fourth U-shaped seat 62 in a direction close to the guide plate 3. The support bars on the third U-shaped seat 61 and the fourth U-shaped seat 62 are arranged facing each other, and the opposite ends do not touch, that is, the first support bar does not touch the third support bar, and the second support bar does not touch the fourth support bar, thereby expanding the deformation space.

[0052] In this embodiment, a flexible polymer component 7 extending from the front end of the first U-shaped seat 51 to the rear end of the second U-shaped seat 52 is provided in the first U-shaped seat 51 and the second U-shaped seat 52; a flexible polymer component 7 extending from the front end of the third U-shaped seat 61 to the rear end of the fourth U-shaped seat 62 is provided in the third U-shaped seat 61 and the fourth U-shaped seat 62. The flexible polymer component 7 is composed of a plurality of flexible units 71 connected together, and a drug coating is provided on the surface of each flexible unit 71, which helps postoperative recovery. The surface of the flexible polymer component 7 without the drug coating is fitted with a gasket component 8, which is composed of a plurality of gasket units, the size of the gasket unit is the same as the size of the flexible unit 71, and the length of the flexible polymer component 7 is the same as that of the gasket component 8.

[0053] When in use, the gasket assembly 8 fits the bottom plate and multiple support strips of the U-shaped plates of the first U-shaped seat 51 and the second U-shaped seat 52; the gasket assembly 8 fits the bottom plate and multiple support strips of the U-shaped plates of the third U-shaped seat 61 and the fourth U-shaped seat 62. After adjusting the distance between the two groups of U-shaped seats, the redundant flexible unit 71 and the gasket unit are torn off along the preset indentation, and the drug coating fits the expanded part. The elastic deformation of the flexible unit 71 and the gasket unit can better adapt to the shape of the expanded part of the sternum. In order to further adapt to the shape of the expanded part of the sternum of different patients, the multiple support strips on the four U-shaped seats can also be adaptively deformed after being subjected to the force of the sternum, which is convenient for the operation.

[0054] In addition, a plurality of suture limiting components are provided on the surface of the first expansion arm body 12 away from the first U-shaped seat 51 and the second U-shaped seat 52; a plurality of suture limiting components are provided on the surface of the second expansion arm body 22 away from the third U-shaped seat 61 and the fourth U-shaped seat 62. The number of suture limiting components on the first expansion arm body 12 is the same as that on the second expansion arm body 22, and they are mirror-imaged. The suture limiting components include a first line groove 91, a second line groove 92 and a third line groove 93; the starting ends of the first line groove 91 and the second line groove 92 face the outside of the expander, the end of the third line groove 93 faces the inside of the expander, and the ends of the first line groove 91 and the second line groove 92 are connected to the starting end of the third line groove 93; the first line groove 91 and the second line groove 92 are symmetrical about the center line of the third line groove 93. A rotatable first pressure wheel 94 is provided in the first wire groove 91, and a rotatable second pressure wheel 95 is provided in the second wire groove 92; the first pressure wheel 94 and the second pressure wheel 95 are arranged opposite to each other and rotate in opposite directions; the surfaces of the first pressure wheel 94 and the second pressure wheel 95 are both provided with pressure teeth, and the first pressure wheel 94 and the second pressure wheel 95 can be used in conjunction with a torsion spring.

[0055] During the operation, after the sternum is opened, it is necessary to further open the tissues of other surgical sites. Figure 7 A suture enters the first thread groove 91 and extends out through the third thread groove 93, passes through the tissue on one side of the surgical opening, and then passes out through the third thread groove 93 and the second thread groove 92. After adjusting the length of the suture, the two pressing wheels press the suture tightly, and the same operation is performed for each suture limiting assembly 9 that needs to be used. The two expansion arms, the suture limiting assembly 9 and the suture are used to expand the tissue opening of the surgical site from both sides to a size suitable for the operation.

[0056] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A sternal spreader, characterized in that: include: A guide plate (3), wherein a first spreading arm (1) and a second spreading arm (2) are arranged on the guide plate (3), and the distance between the first spreading arm (1) and the second spreading arm (2) is adjustable; The first spreading arm (1) is provided with a first limiting assembly (5), and the second spreading arm (2) is provided with a second limiting assembly (6), and the first limiting assembly (5) and the second limiting assembly (6) are symmetrically arranged; The first U-shaped seat (51) and the second U-shaped seat (52) in the first limiting assembly (5) can move closer to or farther from each other along the axial direction of the first spreading arm (1), and the opposite ends of the first U-shaped seat (51) and the second U-shaped seat (52) can be deformed; The third U-shaped seat (61) and the fourth U-shaped seat (62) of the second limiting assembly (6) can approach or move away from each other along the axial direction of the second spreading arm (2), and the opposite ends of the third U-shaped seat (61) and the fourth U-shaped seat (62) can be deformed.

2. The sternal spreader according to claim 1, characterized in that: The first U-shaped seat (51) and the second U-shaped seat (52) can move along the first spreading arm body (12) of the first spreading arm (1); The first U-shaped seat (51) and the second U-shaped seat (52) each comprise a movable base, each of the movable bases being provided with a U-shaped plate, the U-shaped opening of the U-shaped plate being arranged in a direction away from the second spreading arm (2); A plurality of parallel support strips extending along the axial direction of the first spreading arm body (12) are arranged on the bottom plate of each U-shaped plate, and each of the support strips has a certain elasticity and can be deformed; The support bars on the first U-shaped seat (51) and the second U-shaped seat (52) are arranged facing each other, and the opposite ends do not contact each other.

3. The sternal spreader according to claim 2, characterized in that: The third U-shaped seat (61) and the fourth U-shaped seat (62) can move along the second spreading arm body (22) of the second spreading arm (2); The third U-shaped seat (61) and the fourth U-shaped seat (62) each comprise a movable base, each of the movable bases being provided with a U-shaped plate, the U-shaped opening of the U-shaped plate being arranged in a direction away from the first spreading arm (1); A plurality of parallel support bars extending along the axial direction of the second spreading arm body (22) are arranged on the bottom plate of each U-shaped plate, and each of the support bars has a certain elasticity and can be deformed; The support bars on the third U-shaped seat (61) and the fourth U-shaped seat (62) are arranged facing each other, and the opposite ends do not contact each other.

4. The sternal spreader according to claim 3, characterized in that: The first U-shaped seat (51) and the second U-shaped seat (52) are provided with a flexible polymer component (7) extending from the front end of the first U-shaped seat (51) to the rear end of the second U-shaped seat (52); The third U-shaped seat (61) and the fourth U-shaped seat (62) are provided with a flexible polymer component (7) extending from the front end of the third U-shaped seat (61) to the rear end of the fourth U-shaped seat (62).

5. The sternal spreader according to claim 4, characterized in that: The flexible polymer component (7) is composed of a plurality of connected flexible units (71), and a drug coating is provided on the surface of each flexible unit (71).

6. The sternal spreader according to claim 5, characterized in that: The surface of the flexible polymer component (7) without drug coating is attached to a gasket component (8), and the gasket component (8) is composed of a plurality of gasket units, and the size of the gasket unit is the same as that of the flexible unit (71).

7. The sternal spreader according to claim 6, characterized in that: The gasket assembly (8) fits the bottom plates of the U-shaped plates of the first U-shaped seat (51) and the second U-shaped seat (52) and the plurality of support strips; the gasket assembly (8) fits the bottom plates of the U-shaped plates of the third U-shaped seat (61) and the fourth U-shaped seat (62) and the plurality of support strips.

8. The sternal spreader according to claim 3, characterized in that: A plurality of suture thread limiting components are arranged on the surface of the first spreading arm body (12) away from the first U-shaped seat (51) and the second U-shaped seat (52); A plurality of suture thread limiting components are arranged on the surface of the second spreading arm body (22) away from the third U-shaped seat (61) and the fourth U-shaped seat (62); The number of the suture line limiting components on the first spreading arm body (12) and the number of the suture line limiting components on the second spreading arm body (22) are the same and are arranged in a mirror image.

9. The sternal spreader according to claim 8, characterized in that: The suture thread limiting assembly comprises a first thread groove (91), a second thread groove (92) and a third thread groove (93); the starting ends of the first thread groove (91) and the second thread groove (92) face the outside of the spreader, the end of the third thread groove (93) faces the inside of the spreader, and the ends of the first thread groove (91) and the second thread groove (92) are connected to the starting end of the third thread groove (93); The first wire groove (91) and the second wire groove (92) are symmetrical about the center line of the third wire groove (93).

10. The sternal spreader according to claim 9, characterized in that: A rotatable first pressing wheel (94) is disposed in the first wire groove (91), and a rotatable second pressing wheel (95) is disposed in the second wire groove (92); The first pressing wheel (94) and the second pressing wheel (95) are arranged facing each other and rotate in opposite directions; the surfaces of the first pressing wheel (94) and the second pressing wheel (95) are both provided with pressing teeth.

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