Multi-degree-of-freedom surgical forceps with replaceable forceps heads

Abstract

The present invention discloses a multi-degree-of-freedom surgical forceps with replaceable forceps heads, belonging to the technical field of medical instruments, in order to solve the technical problems in the prior art that the execution end of the surgical forceps and the instrument body cannot be disassembled and reused, thereby making the execution end of a single surgical forceps single in function and the surgical cost high. It comprises: an execution part, the execution part comprises a connecting rod and a forceps head; a conversion assembly, the conversion assembly is connected to the execution part, and comprises a first connecting seat, a nut housing and a second connecting seat; an action conversion part is arranged in the nut housing; an actuating assembly, the actuating assembly is connected to the conversion assembly through an arched arm; transmission wires are evenly arranged in the connecting rod and the arched arm; a handle, the handle is connected to the actuating assembly. The multi-degree-of-freedom surgical forceps with replaceable forceps heads of the present invention can conveniently disassemble and replace the execution end of the surgical forceps, can meet different surgical needs, and achieve the purpose of saving medical resources and reducing surgical costs.

Description

Technical Field

[0001] The present invention relates to the technical field of medical instruments, and in particular to a multi-degree-of-freedom surgical forceps with replaceable forceps heads. Background Art

[0002] Minimally invasive surgery refers to the use of slender surgical tools by doctors to penetrate the body through tiny incisions on the surface of the human body to perform surgical operations. Compared with traditional open surgery, it has the advantages of smaller surgical incisions, less bleeding, smaller postoperative scars, and faster recovery time, which greatly reduces the pain suffered by patients. Therefore, minimally invasive surgical instruments are widely used in clinical surgery and are essential tools for surgical operations. They can perform different functions, including clamping, resection, cutting, suturing, and anastomosis. Currently, most minimally invasive surgical instruments are hand-controlled straight-rod instruments. The end effector of the instrument only has the freedom of opening and closing, and has no joint deflection function. The instrument operation flexibility is low, which increases the difficulty of surgical operation.

[0003] To solve the above problems, some companies at home and abroad have developed multi-degree-of-freedom surgical instruments, which enable the instruments to have freedom in multiple directions such as opening and closing, pitching and yaw, thereby increasing the flexibility of minimally invasive surgical instruments, such as the multi-degree-of-freedom instruments disclosed in U.S. Patent No. US18207640 and Chinese Patent Application No. CN202210193363.6. However, the execution ends of these schemes are fixedly connected to the instrument rod and the instrument body, and the internal transmission wires and their transmission structures are inseparable from the instrument as a whole. Therefore, these published multi-degree-of-freedom instruments can only be used for one operation and have only one surgical function. They cannot be reused and cannot achieve other functions by only replacing the ends. This causes a waste of medical resources and leads to high surgical costs. Summary of the Invention

[0004] The purpose of the present invention is to provide a multi-degree-of-freedom surgical forceps with replaceable forceps heads to solve the technical problems in the prior art that the surgical forceps execution end and the instrument body cannot be disassembled and reused, thereby resulting in a single surgical forceps execution end having a single function and high surgical costs.

[0005] To achieve the above objectives, the present invention provides the following technical solutions:

[0006] The present invention provides a multi-degree-of-freedom surgical forceps with replaceable forceps heads, comprising:

[0007] The executing part includes a connecting rod and a clamp head;

[0008] The conversion assembly is connected to the execution part, and the conversion assembly includes a first connection seat, a nut shell and a second connection seat; the action conversion part is provided in the nut shell;

[0009] an actuating assembly connected to the conversion assembly via an arched arm;

[0010] Transmission wires are arranged in the connecting rod and the bow-shaped arm, one end of the transmission wire in the connecting rod is connected to the pliers head, and the other end is connected to the action conversion part;

[0011] One end of the transmission wire in the bow-shaped arm is connected to the actuating assembly, and the other end is connected to the motion conversion part;

[0012] A handle is connected to the actuating assembly.

[0013] The operator holds the handle and operates the actuating assembly, which converts the operator's hand operation into the movement of the transmission wire through the actuating assembly. The transmission wire transmits and converts the movement from the actuating assembly to the conversion assembly through the bow arm. The conversion assembly is affected by the transmission wire and synchronously converts the movement of the transmission wire into the movement of the forceps head. By operating the actuating assembly, the operator can achieve multi-degree-of-freedom synchronous control of the forceps head, including synchronous opening and closing, pitch and yaw of the forceps head, thereby achieving good surgical results.

[0014] In addition, the execution part is detachably connected to the instrument body, which allows the instrument body to be reused multiple times, saving medical resources and reducing surgical costs.

[0015] Optionally or preferably, the action conversion portion includes a first connection block connected to the first connection seat and a second connection block connected to the second connection seat;

[0016] The first connecting block includes a mounting plate 1, on which a single or multiple mounting holes 1 are formed, and the mounting holes 1 are used to mount a transmission wheel set 1;

[0017] The second connecting block includes a second mounting plate, on which a single or multiple second mounting holes are formed, and the second mounting holes are used to mount the second transmission wheel set;

[0018] The first transmission wheel set is cooperatively connected with the second transmission wheel set.

[0019] Optionally or preferably, the transmission wheel set 1 and the transmission wheel set 2 both include a transmission shaft, a rotating gear is fixedly connected to the middle of the transmission shaft, bearings and winding wheels are provided on both sides of the rotating gear, and a spiral groove is opened on the winding wheel; the spiral groove is used for winding the transmission wire;

[0020] The bearing in the transmission wheel set 1 is fixed in the mounting hole 1; the bearing in the transmission wheel set 2 is fixed in the mounting hole 2;

[0021] The rotating gear in the transmission wheel set 1 is meshed with the rotating gear in the transmission wheel set 2.

[0022] Optionally or preferably, the number of the mounting holes 1 is 2; the transmission wheel set 1 includes a first wheel set and a second wheel set;

[0023] The number of the second mounting holes is 2; the second transmission wheel group includes a third wheel group and a fourth wheel group.

[0024] Multi-degree-of-freedom control of the surgical forceps head is achieved through the first wheel group, the second wheel group, the third wheel group and the fourth wheel group. Different wheel groups combined with corresponding transmission wires can realize transmission control of one degree of freedom of the forceps head. For example, the transmission cooperation of the first wheel group and the fourth wheel group can realize the opening and closing of one side of the forceps head (left or right) separately; the transmission cooperation of the second wheel group and the third wheel group can realize the opening and closing of the other side of the forceps head (left or right); the transmission cooperation of the first wheel group, the fourth wheel group and the second wheel group and the third wheel group at the same time and in the same direction can realize the left and right swing movement of the entire forceps head; the simultaneous transmission cooperation of the winding wheels on the same side of the first wheel group and the second wheel group and the winding wheels on the same side of the third wheel group and the fourth wheel group in the opposite directions can realize the pitching movement of the forceps head respectively.

[0025] Optionally or preferably, a positioning pin is provided on the first mounting plate; a positioning hole is provided on the second mounting plate; and the positioning pin is matched and connected with the positioning hole.

[0026] Optionally or preferably, the transmission wire is a wear-resistant flexible rope.

[0027] Optionally or preferably, both the first mounting plate and the second mounting plate have a clamping portion;

[0028] The first mounting plate and the second mounting plate are respectively connected to the first connecting seat and the second connecting seat through the connecting parts.

[0029] Optionally or preferably, the starting point of the helical groove is adapted to the shape of the end of the transmission wire.

[0030] By providing a spiral groove on the winding wheel, the transmission wire can be wound around the winding wheel and tightened, so that the rotating gears of the first wheel group and / or the second wheel group in the first connecting block can be rotated under the drive of the transmission wire tensioning force, thereby converting the linear motion of the transmission wire wound around the first wheel group and the second wheel group into the rotational motion of the rotating gears in the first wheel group and the second wheel group, and then through the meshing relationship between the rotating gears in the first wheel group and the second wheel and the rotating gears in the third wheel group and the fourth wheel group, the rotational motion of the first wheel group and the second wheel group is converted into the rotational motion of the rotating gears in the third wheel group and the fourth wheel group, so that the transmission wire wound around the third wheel group and the fourth wheel group moves and is tensioned, thereby converting the rotational motion into the linear motion of the transmission wire and then driving the pliers head to move in the corresponding degree of freedom.

[0031] Optionally or preferably, one end of the first connecting seat is fixedly connected to the bow arm, and the other end is threadedly connected to the nut housing;

[0032] One end of the second connecting seat is clamped with the nut shell, and the other end is detachably connected to the connecting rod.

[0033] Based on the above technical solution, the present invention can produce at least the following technical effects:

[0034] (1) The multi-degree-of-freedom surgical forceps with replaceable forceps heads provided by the present invention converts the operator's hand operation into the movement of the transmission wire through an actuating assembly, and then synchronously converts the movement of the transmission wire into the movement of the forceps heads through a conversion assembly; the operator can achieve multi-degree-of-freedom synchronous control of the forceps heads by operating the actuating assembly, including synchronous opening and closing, pitching and yaw of the forceps heads, thereby achieving good surgical results;

[0035] (2) The conversion assembly is provided so that the actuator can be detachably connected to the instrument body, and the transmission wire and the connecting rod of the actuator can be separated from the instrument body, so that the instrument body can be reused multiple times and the forceps with other functions can be easily replaced, saving medical resources and reducing surgical costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a schematic diagram of the overall structure of the multi-degree-of-freedom surgical forceps with replaceable forceps heads according to the present invention;

[0037] Figure 2 1 is a front view of the multi-degree-of-freedom surgical forceps with replaceable forceps heads according to the present invention;

[0038] Figure 3 It is a front view of a conversion assembly in a multi-degree-of-freedom surgical forceps with replaceable forceps heads according to the present invention;

[0039] Figure 4 This is a front view of the conversion assembly (the nut housing is omitted) in the multi-degree-of-freedom surgical forceps with replaceable forceps heads of the present invention;

[0040] Figure 5 It is a partial structural diagram of the first connecting seat in the multi-degree-of-freedom surgical forceps with replaceable forceps heads of the present invention;

[0041] Figure 6 It is a partial structural diagram of the second connecting seat in the multi-degree-of-freedom surgical forceps with replaceable forceps heads of the present invention;

[0042] Figure 7 This is a schematic structural diagram of a mounting plate 1 in a multi-degree-of-freedom surgical forceps with replaceable forceps heads according to the present invention;

[0043] Figure 8 This is a schematic structural diagram of the mounting plate 2 in the multi-degree-of-freedom surgical forceps with replaceable forceps heads according to the present invention;

[0044] Figure 9 This is a schematic structural diagram of the motion conversion portion of the multi-degree-of-freedom surgical forceps with replaceable forceps heads according to the present invention;

[0045] Figure 10It is a top view of the motion conversion part of the multi-degree-of-freedom surgical forceps with replaceable forceps heads of the present invention.

[0046] In the figure: 10, executive part; 11, connecting rod; 12, pliers head; 20, conversion assembly; 21, first connecting seat; 22, nut housing; 23, second connecting seat; 24, first connecting block; 25, second connecting block; 26, positioning hole; 27, mounting hole one; 28, transmission wheel group one; 29, winding wheel; 210, bearing; 211, mounting hole two; 212, transmission wheel group two; 213, first wheel group; 214, second wheel group; 215, third wheel group; 216, fourth wheel group; 217, positioning pin; 218, rotating gear; 219, transmission shaft; 30, actuating assembly; 40, bow arm; 50, handle. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making creative work shall fall within the scope of protection of the present invention.

[0048] Example

[0049] See also Figures 1 to 2 A multi-degree-of-freedom surgical forceps with replaceable forceps heads includes a handle 50, an actuating assembly 30, a bow arm 40, a conversion assembly 20, and an actuator 10 detachably connected to the conversion assembly 20, which are connected in sequence.

[0050] The handle 50 is used to install the above-mentioned actuating assembly 30 and support the entire surgical forceps structure, so that the doctor can hold it easily; the actuating assembly 30 is used to convert the doctor's hand operation into the movement of the transmission wire, and then control the execution part 10 to operate through the movement of the transmission wire; the bow arm 40 is used to connect the actuating assembly 30 and the conversion assembly 20, and there is space in the bow arm 40 for arranging the above-mentioned transmission wire, so that the operation from the actuating assembly 30 can be transmitted to the conversion assembly 20 through the transmission wire; the conversion assembly 20 is used to convert the movement of the transmission wire into the action of the execution part 10.

[0051] In this embodiment, the execution part 10 includes a connecting rod 11 and a pliers head 12, wherein a transmission wire is arranged inside the connecting rod 11, one end of the transmission wire is connected to the above-mentioned pliers head 12, and the other end passes through the conversion assembly 20 and the bow arm 40 in sequence and is finally connected to the actuator assembly 30.

[0052] In actual work, the doctor holds the handle 50 and operates the actuating assembly 30. Under the transmission action of the transmission wire, the conversion assembly 20 can convert the doctor's hand operation into synchronous opening and closing, pitching and yaw movements of the forceps head 12.

[0053] See also Figure 3 and Figure 4 Specifically, the conversion assembly 20 includes a first connecting seat 21, a nut housing 22 and a second connecting seat 23, wherein one end of the first connecting seat 21 is fixed to the bow arm 40 by fasteners such as screws and bolts, and the other end is threadedly connected to the nut housing 22; one end of the second connecting seat 23 is clamped to the nut housing 22, and the other end is clamped to one end of the connecting rod 11.

[0054] In this embodiment, a motion conversion unit is provided in the nut housing 22 , and the motion conversion unit is used to convert its own rotational motion into the linear motion of the transmission wire, thereby converting the doctor's hand operation into a multi-degree-of-freedom motion of the forceps head 12 .

[0055] See also Figure 5 and Figure 6 Specifically, the action conversion portion includes a first connecting block 24 connected to the first connecting seat 21 and a second connecting block 25 connected to the second connecting seat 23;

[0056] See also Figure 7 and Figure 8 , wherein the first connecting block 24 includes a mounting plate 1, which can be formed by splicing multiple plates or can be an integrally formed setting; in this embodiment, the mounting plate 1 is composed of two bilaterally symmetrical mounting blocks, each of which has two mounting holes 1 27, and a transmission wheel set 1 28 is disposed in each corresponding mounting hole 1 27;

[0057] The second connecting block 25 includes a second mounting plate. Similar to the first mounting plate, the second mounting plate can also be formed by splicing multiple plates or forming an integral structure. In this embodiment, the second mounting plate is composed of two bilaterally symmetrical mounting blocks, each of which has two second mounting holes 211 formed therein. A second transmission wheel assembly 212 is disposed in each of the second mounting holes 211.

[0058] It can be understood that the number of mounting holes set on the mounting block and the number of wheel sets set are related to the degree of freedom control of the pliers head. Only one mounting hole can be set on each mounting block to install the wheel set, and a total of two wheel sets can be used to achieve transmission control of only one degree of freedom; or more than three mounting holes can be set on each mounting block to install multiple wheel sets to achieve transmission control of more than three degrees of freedom.

[0059] In this embodiment, a positioning pin 217 is provided on the mounting plate 1, and a corresponding positioning hole 26 is provided on the mounting plate 2, and the positioning pin 217 and the positioning hole 26 are matched and connected; in addition, both the mounting plate 1 and the mounting plate 2 have a clamping portion, through which the mounting plate 1 and the mounting plate 2 are respectively clamped with the first connecting seat 21 and the second connecting seat 23. It can be understood that the first connecting seat 21 and the second connecting seat 23 have corresponding clamping grooves.

[0060] See also Figure 9 and Figure 10 In this embodiment, the transmission wheel group 1 28 includes a first wheel group 213 and a second wheel group 214; the transmission wheel group 212 includes a third wheel group 215 and a fourth wheel group 216; the first wheel group 213, the second wheel group 214, the third wheel group 215 and the fourth wheel group 216 all include a transmission shaft 219, and a rotating gear 218 is fixedly connected to the middle of the transmission shaft 219 of each wheel group. The rotating gear 218 is provided with bearings 210 and a winding wheel 29 on both sides; wherein the bearings 210 in the first wheel group 213 and the second wheel group 214 are fixed to the middle of the transmission shaft 219 of each wheel group. 10 is fixed in the mounting hole 1 27 on the mounting plate 1, and the rotating gear 218 is located between the corresponding two mounting holes 1 27; the setting method of the third wheel group 215 and the fourth wheel group 216 is similar to the above-mentioned first wheel group 213 and the second wheel group 214, that is, the bearing 210 is fixed in the mounting hole 211 on the mounting plate 2, and its rotating gear 218 is located between the corresponding two mounting holes 211; the rotating gear 218 located between the mounting holes 1 27 is meshed and connected with the rotating gear 218 located between the mounting holes 211.

[0061] In this embodiment, the transmission wheel group 1 28 is a driving wheel, which is rotated by the tension of the transmission wire connected to the actuating assembly 30, and then drives the transmission wheel group 2 212 to transmit through the meshing relationship with the transmission wheel group 2 212; Specifically, a spiral groove is opened on the side wall of the winding wheel 29, and the groove is used to wind the transmission wire and tighten it, so that the rotating gear 218 in the transmission wheel group 1 28 can be rotated under the drive of the transmission wire tension, thereby converting the linear motion of the transmission wire wound on the transmission wheel group 1 28 into the first gear. The rotational motion of the first wheel group 213 and the second wheel group 214 is then converted into the rotational motion of the third wheel group 215 and the fourth wheel group 216 through the gear meshing relationship, that is, the rotating gear 218 in the third wheel group 215 and the fourth wheel group 216 is driven to rotate, so that the transmission wire wrapped around the third wheel group 215 and the fourth wheel group 216 moves and is tensioned, and the rotational motion is then converted into the linear motion of the transmission wire, which drives the pliers head 12 to move in the corresponding degree of freedom.

[0062] In actual operation, this embodiment realizes transmission control of one degree of freedom of the pliers head 12 by combining different wheel groups with corresponding transmission wires; for example, the transmission cooperation of the first wheel group 213 and the fourth wheel group 216 can realize the opening and closing of one side (left or right) of the pliers head 12 independently; the transmission cooperation of the second wheel group 214 and the third wheel group 215 can realize the opening and closing of the other side (left or right) of the pliers head 12; the transmission cooperation of the first wheel group 213, the fourth wheel group 216, the second wheel group 214, and the third wheel group 215 at the same time and in the same direction can realize the left and right swing movement of the entire pliers head 12; the simultaneous transmission cooperation of the winding wheels on the same side of the first wheel group 213 and the second wheel group 214 and the winding wheels on the same side of the third wheel group 215 and the fourth wheel group 216 in the opposite directions can respectively realize the pitching movement of the pliers head 12.

[0063] In this embodiment, the starting point of the above-mentioned spiral groove is adapted to the shape of the end of the transmission wire (such as a cylinder or a sphere), such as a cylindrical or spherical groove; in this embodiment, the transmission wire is a flexible rope with a certain strength and wear resistance, such as a steel wire rope.

[0064] The present invention provides a multi-degree-of-freedom surgical forceps with replaceable forceps heads. Compared with the prior art method in which the execution end is non-detachably and fixedly connected to the instrument body through the instrument rod, the execution part 10 of the present invention is detachable and divisible from the instrument body. The staff can conveniently remove the execution part 10 from the instrument body through a conversion assembly composed of multiple wheel groups, and then reinstall a new execution end for continued use, thereby realizing the reuse of the instrument body. By replacing the execution end with other functions, the switching of different surgical forceps functions can also be realized, such as changing cutting to suturing, thereby achieving the purpose of saving medical resources and reducing surgical costs.

[0065] The second connecting block 25 is connected to the connecting rod 11 with the clamp head 12 and the transmission wire, and the second connecting block 25 on which the third wheel group 215 and the fourth wheel group 216 are installed is connected to the second connecting block 23, and the transmission wire is wound onto the winding wheel 29 of the third wheel group 215 and the fourth wheel group 216 for tightening; then the positioning pin 217 on the first connecting block 24 which is pre-installed on the bow arm 40 through the first connecting block 21 is abutted through the positioning hole 26 on the second connecting block 25, and the rotating gear 218 on the transmission wheel group 1 28 and the transmission wheel group 2 212 is meshed, and finally the nut housing 22 is put on to further strengthen and protect the connection between the two, and finally the installation connection between the executing part 10 and the instrument body is realized.

[0066] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "provided with," "mounted / connected," and "connected" should be understood in a broad sense. For example, "connected" can mean a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be internal communication between two components. Those skilled in the art will be able to understand the specific meanings of the above terms in the present invention in specific circumstances.

[0067] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A multi-degree-of-freedom surgical forceps with replaceable forceps heads, characterized in that: include: An execution part (10), the execution part (10) comprising a connecting rod (11) and a clamp head (12); a conversion assembly (20), the conversion assembly (20) being connected to the execution unit (10), the conversion assembly (20) comprising a first connection seat (21), a nut housing (22) and a second connection seat (23); an action conversion unit is arranged in the nut housing (22); an actuating assembly (30), the actuating assembly (30) being connected to the conversion assembly (20) via a bow-shaped arm (40); Transmission wires are evenly distributed in the connecting rod (11) and the bow-shaped arm (40); one end of the transmission wire in the connecting rod (11) is connected to the pliers head (12), and the other end is connected to the action conversion part; One end of the transmission wire in the bow-shaped arm (40) is connected to the actuating assembly (30), and the other end is connected to the action conversion portion; A handle (50), the handle (50) being connected to the actuating assembly (30); The action conversion portion comprises a first connection block (24) connected to the first connection seat (21) and a second connection block (25) connected to the second connection seat (23); The first connecting block (24) comprises a mounting plate 1, the mounting plate 1 is provided with a mounting hole 1 (27), the number of the mounting holes 1 (27) is 2, and the mounting holes 1 (27) are used to set a transmission wheel set 1 (28); The second connecting block (25) comprises a second mounting plate, the second mounting plate is provided with a second mounting hole (211), the number of the second mounting holes (211) is 2, and the second mounting holes (211) are used to set the second transmission wheel set (212); The transmission wheel set 1 (28) is cooperatively connected with the transmission wheel set 2 (212); One end of the first connecting seat (21) is fixedly connected to the bow-shaped arm (40), and the other end is threadedly connected to the nut housing (22); One end of the second connecting seat (23) is snap-connected to the nut housing (22), and the other end is detachably connected to the connecting rod (11); The transmission wheel set 1 (28) and the transmission wheel set 2 (212) both comprise a transmission shaft (219), a rotating gear (218) being fixedly connected to the middle of the transmission shaft (219), bearings (210) and a winding wheel (29) being arranged on both sides of the rotating gear (218), and a spiral groove being provided on the winding wheel (29); the spiral groove being used for winding the transmission wire; The bearing (210) in the transmission wheel set 1 (28) is fixed in the mounting hole 1 (27); the bearing (210) in the transmission wheel set 2 (212) is fixed in the mounting hole 2 (211); The rotating gear (218) in the transmission wheel set 1 (28) is meshed with the rotating gear (218) in the transmission wheel set 2 (212); The transmission wheel set 1 (28) comprises a first wheel set (213) and a second wheel set (214); The second transmission wheel set (212) comprises a third wheel set (215) and a fourth wheel set (216).

2. The multi-degree-of-freedom surgical forceps with replaceable forceps heads according to claim 1, characterized in that: The first mounting plate is provided with a positioning pin (217); the second mounting plate is provided with a positioning hole (26); the positioning pin (217) is matched and connected with the positioning hole (26).

3. The multi-degree-of-freedom surgical forceps with replaceable forceps heads according to claim 2, characterized in that: The transmission wire is a wear-resistant flexible rope.

4. The multi-degree-of-freedom surgical forceps with replaceable forceps heads according to claim 1, characterized in that: The first mounting plate and the second mounting plate both have a clamping portion; The first mounting plate and the second mounting plate are respectively clamped with the first connecting seat (21) and the second connecting seat (23) via clamping parts.

5. The multi-degree-of-freedom surgical forceps with replaceable forceps heads according to claim 1, characterized in that: The starting point of the spiral groove is adapted to the shape of the end of the transmission wire.

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