Orthopedic surgery assisting device

Abstract

The present invention belongs to the technical field of auxiliary tools for orthopedic surgery, and discloses an orthopedic surgery auxiliary device, comprising a traction mechanism arranged along the Y axis, and a front clamping mechanism and a rear clamping mechanism respectively connected to the two ends of the traction mechanism; the traction mechanism is used to adjust the traction distance between the front clamping mechanism and the rear clamping mechanism; the front clamping mechanism comprises a lifting drive component and a rotatable front C-arm, and the lifting drive component is used to drive the front C-arm to lift and lower along the Z axis; the rear clamping mechanism comprises a moving drive component and a rotatable rear C-arm, and the moving drive component is used to drive the rear C-arm to move along the X axis; the front C-arm and the rear C-arm are both spirally penetrated with two symmetrically arranged positioning steel nails; as mentioned above, the front clamping mechanism can perform longitudinal adjustment, and the rear clamping mechanism can perform lateral adjustment, thereby effectively ensuring that the fracture site can be accurately aligned during the operation, and the overall operation is convenient.

Description

Technical Field

[0001] The present invention belongs to the technical field of auxiliary tools for orthopedic surgery, and in particular relates to an auxiliary device for orthopedic surgery. Background Art

[0002] Take fracture surgery as an example. During orthopedic surgery and treatment, it is often necessary to clamp and traction the bones at the fracture site to promote the natural growth and repair of human bones. In traditional surgical operations, the traction and reduction of fractured bones is mostly done by medical staff holding clamps in their hands, using the clamps to clamp the bones to be reduced, and then manually moving and stretching the bones, and finally fixing them with bone screws, steel plates and other tools; although the above method can achieve a certain reduction and traction effect, it is cumbersome to operate, and requires the cooperation of multiple people during the specific operation.

[0003] In addition, manual traction reduction relies on human power to pull the bones to move, and different medical staff have different strengths. Therefore, when the bones are manually pulled to reduce the fracture, they are affected by different forces, making it difficult to ensure the precise positioning of the bones at the fracture site. Summary of the invention

[0004] In view of this, in order to solve the problems raised in the above background technology, an object of the present invention is to provide an orthopedic surgery auxiliary device.

[0005] To achieve the above-mentioned object, the present invention provides the following technical solutions: an orthopedic surgery auxiliary device, comprising a traction mechanism arranged along the Y axis, and a front clamping mechanism and a rear clamping mechanism respectively connected to both ends of the traction mechanism;

[0006] The traction mechanism is used to adjust the traction distance between the front clamping mechanism and the rear clamping mechanism;

[0007] The front clamping mechanism includes a lifting drive component and a rotatable front C-arm, and the lifting drive component is used to drive the front C-arm to lift and lower along the Z axis; the rear clamping mechanism includes a moving drive component and a rotatable rear C-arm, and the moving drive component is used to drive the rear C-arm to move along the X axis; the front C-arm and the rear C-arm are both spirally penetrated by two symmetrically arranged positioning steel nails.

[0008] Preferably, the front clamping mechanism comprises:

[0009] A front mounting base with an opening at the top, and one end of the traction mechanism is connected to the outside of the front mounting base;

[0010] A limit assembly is liftably arranged inside the front mounting base; the limit assembly includes two symmetrically arranged slides and two limit gear rollers rotatably installed between the two slides, the two slides are respectively slidably connected to the inner walls on both sides of the front mounting base, and the two limit gear rollers are respectively meshed and connected to the inner and outer side walls of the front C-arm.

[0011] Preferably, the lifting drive assembly in the front clamping mechanism includes:

[0012] Two movable frames are movably arranged inside the front mounting base, the two movable frames are symmetrically distributed on both sides of the limiting gear roller, and the two movable frames move synchronously towards or in opposite directions;

[0013] The movable gear rollers mounted on the movable frame are rotatably connected, and the two movable gear rollers are meshedly connected with the outer side wall of the front C-arm.

[0014] Preferably, a limit spring is connected between the bottom of the slide and the bottom wall of the front mounting base, and the limit spring is used to press the front C-arm onto the movable gear roller from top to bottom.

[0015] Preferably, the lifting drive assembly in the front clamping mechanism further includes:

[0016] Rotating a first lead screw installed inside the front mounting base;

[0017] The spiral sleeves are arranged on two first thread sleeves on the first lead screw; the two first thread sleeves are fixedly connected to two moving frames respectively, and when the first lead screw rotates, the two first thread sleeves move synchronously towards or in opposite directions.

[0018] Preferably, a first driving motor is fixed on the outer wall of one side of any one of the movable frames, and the corresponding one of the movable gear rollers includes an inner roller and an outer roller that can rotate relative to each other, the inner roller is driven to rotate by the first driving motor, and at least one mounting groove is arranged in an array on the outer wall of the inner roller, an electric push rod is installed in each of the mounting grooves, and a limit block that can engage with the inner wall of the outer roller is fixed to the telescopic end of the electric push rod.

[0019] Preferably, the rear clamping mechanism comprises:

[0020] A rear mounting base with an opening at the top;

[0021] A drive assembly rotatably arranged inside the rear mounting base; the drive assembly includes two drive gear rollers arranged in sequence from top to bottom, the two drive gear rollers are respectively meshed and connected with the inner and outer side walls of the rear C-arm, and the two drive gear rollers include a driving gear roller and a driven gear roller;

[0022] A second driving motor is fixed on an outer wall of one side of the rear mounting base, and the active gear roller is driven to rotate by the second driving motor.

[0023] Preferably, the mobile driving assembly in the rear clamping mechanism includes:

[0024] A fixed base with a slide groove on the top, and the other end of the traction mechanism is connected to the outside of the fixed base;

[0025] Rotating a second lead screw installed inside the fixed base;

[0026] The spiral sleeve is arranged on at least one second threaded sleeve on the second lead screw, and the second threaded sleeve passes through the slide groove and is fixedly connected to the rear mounting base.

[0027] Preferably, scale marks are provided on the inner wall and / or the side wall of the front C-arm and the rear C-arm, and the scale marks are used to mark the current rotation angles of the front C-arm and the rear C-arm.

[0028] Preferably, the traction mechanism comprises:

[0029] A traction outer rod is provided with a cavity inside, and a threaded column is rotatably mounted on one side wall of the traction outer rod;

[0030] The inner traction rod is slidably matched in the cavity of the outer traction rod, and a thread groove is opened on one side wall of the inner traction rod, and one side of the thread column is screwed and connected to the inside of the thread groove, and the other side is limited to the outside of the outer traction rod.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) In the present invention, a front clamping mechanism and a rear clamping mechanism that can adjust the traction distance are symmetrically arranged, wherein the front clamping mechanism can perform longitudinal adjustment, and the rear clamping mechanism can perform lateral adjustment, thereby effectively ensuring that the fracture site can be accurately aligned during the operation, and the overall operation is convenient.

[0033] (2) With respect to the front clamping mechanism, a front C-arm and two movable gear rollers that mesh with each other are provided. Specifically, when the two movable gear rollers approach each other, the front C-arm can be pushed up, and when the two movable gear rollers move away from each other, the front C-arm automatically descends under the limitation of the limit assembly. Thus, the lifting and lowering adjustment of the front clamping mechanism is effectively realized, and the overall adjustment structure is simple.

[0034] (3) With respect to the above-mentioned movable gear roller, the inner roller and the outer roller cooperate to form a separable and cooperable combined structure, based on which: when the two movable gear rollers approach each other, based on the separation of the inner roller and the outer roller, the two outer rollers can freely rotate in opposite directions without affecting the inner roller; when adjusting the positioning angle of the front C-arm, based on the cooperation of the inner roller and the outer roller, the rotation of the inner roller can drive the outer roller that cooperates with it to rotate, thereby realizing the meshing drive between the movable gear roller and the front C-arm. In summary, the lifting and rotation drive of the front C-arm is effectively realized based on the same structure, and the two drives do not interfere with each other.

[0035] (4) With respect to the above-mentioned movable gear roller and rear clamping mechanism, their movement is driven by a lead screw structure, which has a simple structure and stable driving and positioning. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A top view of the present invention;

[0037] Figure 2 It is a structural schematic diagram of the traction mechanism in the present invention;

[0038] Figure 3 It is a structural schematic diagram of the front clamping mechanism in the present invention;

[0039] Figure 4 for Figure 3 A in the enlarged view;

[0040] Figure 5 It is a schematic diagram of the principle of the movable gear roller in the present invention when it moves and rotates;

[0041] Figure 6 It is a structural schematic diagram of the rear clamping mechanism in the present invention;

[0042] In the figure:

[0043] Traction mechanism-1; traction outer rod-11; threaded column-12; traction inner rod-13; threaded groove-14;

[0044] Front clamping mechanism-2; front C-arm-21; front mounting base-22; slide-23; limit gear roller-24; moving frame-25; first driving motor-251; moving gear roller-26; inner roller-261; outer roller-262; electric push rod-263; limit block-264; limit spring-27; first lead screw-28; first threaded sleeve-29;

[0045] Rear clamping mechanism-3; rear C-arm-31; rear mounting base-32; driving gear roller-33; second driving motor-34; fixed base-35; second lead screw-36; second threaded sleeve-37;

[0046] Positioning steel nails-4. 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, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] See also Figure 1-Figure 6 As shown, an orthopedic surgery auxiliary device is provided in the present invention, and the device mainly includes the following structures: a traction mechanism 1 arranged along the Y axis, and a front clamping mechanism 2 and a rear clamping mechanism 3 respectively connected to the two ends of the traction mechanism 1.

[0049] Above

[0050] The traction mechanism 1 is used to adjust the traction distance between the front clamping mechanism 2 and the rear clamping mechanism 3, and is combined with Figure 2 As shown, the traction mechanism 1 comprises:

[0051] A traction outer rod 11 with a cavity inside is provided, and a threaded column 12 is rotatably mounted on one side wall of the traction outer rod 11;

[0052] The traction inner rod 13 is slidably fitted in the cavity of the traction outer rod 11, and a thread groove 14 is opened on one side wall of the traction inner rod 13, and one side of the thread column 12 is screwed and connected to the inside of the thread groove 14, and the other side is limited to the outside of the traction outer rod 11.

[0053] From the above, it can be seen that the principle of adjusting the traction distance by the traction mechanism 1 is:

[0054] The threaded column 12 located outside the traction outer rod 11 is manually turned, and the threaded column 12 rotates and spirally transmits with the thread groove 14, thereby driving the traction inner rod 13 to move, thereby changing the distance between the two ends of the overall traction mechanism 1, and further achieving the effect of adjusting the traction distance between the front clamping mechanism 2 and the rear clamping mechanism 3.

[0055] Above

[0056] The front clamping mechanism 2 includes a lifting drive assembly and a rotatable front C arm 21, and the lifting drive assembly is used to drive the front C arm 21 to lift and lower along the Z axis;

[0057] The rear clamping mechanism 3 includes a mobile driving assembly and a rotatable rear C-arm 31, and the mobile driving assembly is used to drive the rear C-arm 31 to move along the X-axis;

[0058] Two symmetrically arranged positioning steel nails 4 are spirally penetrated on both the front C arm 21 and the rear C arm 31 .

[0059] As can be seen from the above, the principle of the auxiliary device disclosed above in performing traction reduction of the bone at the fracture site is:

[0060] According to the actual fracture status of the patient, the positioning angles of the front C-arm 21 and the rear C-arm 31 are rotated and adjusted to facilitate driving the positioning steel nail 4 at an appropriate position and angle. After adjusting the angle, the positioning steel nail 4 is rotated so that the positioning steel nail 4 is driven into the patient's bone to complete the connection between the overall device and the patient's bone. Then, according to the dislocation status of the patient's fractured bone, the longitudinal position of the front clamping mechanism 2 along the Z axis and the lateral position of the rear clamping mechanism 3 along the X axis are adjusted to ensure the precise alignment of the dislocated bones. On this basis, the traction mechanism 1 is used to perform contraction traction to effectively achieve bone repositioning and repair.

[0061] Specific, combined Figure 3-Figure 5 It can be seen that regarding the front clamping mechanism 2, the following implementation structure is provided.

[0062] The front clamping mechanism 2 comprises:

[0063] A front mounting base 22 with an opening at the top, one end of the traction mechanism 1 is connected to the outside of the front mounting base 22;

[0064] A limit assembly is arranged inside the front mounting base 22 and can be raised and lowered; the limit assembly includes two symmetrically arranged slides 23 and two limit gear rollers 24 rotatably installed between the two slides 23, the two slides 23 are respectively slidably connected to the inner walls on both sides of the front mounting base 22, and the two limit gear rollers 24 are respectively meshed and connected to the inner and outer side walls of the front C-arm 21.

[0065] The lifting drive assembly in the front clamping mechanism 2 includes:

[0066] Two movable frames 25 are movably arranged inside the front mounting base 22, and the two movable frames 25 are symmetrically distributed on both sides of the limiting gear roller 24, and the two movable frames 25 move synchronously toward or in the opposite direction;

[0067] The movable gear rollers 26 mounted on the movable frame 25 are rotatably connected, and both movable gear rollers 26 are meshedly connected with the outer side wall of the front C-arm 21 .

[0068] Preferably, a limit spring 27 is connected between the bottom of the slide 23 and the bottom wall of the front mounting base 22 , and the limit spring 27 is used to press the front C-arm 21 against the movable gear roller 26 from top to bottom.

[0069] As can be seen from the above, the lifting principle of the front C-arm 21 is:

[0070] The two movable racks 25 drive the two movable gear rollers 26 to approach each other. At this time, the two movable gear rollers 26 rotate in opposite directions to engage and move toward the lowest point of the front C-arm 21. The height of the movable gear rollers 26 remains unchanged, thereby driving the front C-arm 21 to rise upward. At the same time, the front C-arm 21 drives the slide 23 to rise through the limitation of the two limit gear rollers 24, thereby stretching the limit spring 27.

[0071] The two moving racks 25 drive the two moving gear rollers 26 away from each other. At this time, the two moving gear rollers 26 do not rotate, and the distance between them and the front C arm 21 increases. At the same time, based on the loss of height limitation of the front C arm 21, the limit spring 27 contracts, thereby pulling the slide 23 and the two limit gear rollers 24 downward, and the two limit gear rollers 24 pull the front C arm 21 downward, thereby realizing the downward adjustment of the front C arm 21. As the front C arm 21 descends, its outer wall is meshed and limited on the moving gear roller 26, thereby ensuring the stable assembly of the moving gear roller 26 and the front C arm 21 after adjustment.

[0072] Furthermore, the lifting drive assembly in the front clamping mechanism 2 also includes:

[0073] Rotate a first lead screw 28 mounted inside the front mounting base 22;

[0074] The two first threaded sleeves 29 are spirally sleeved on the first lead screw 28; the two first threaded sleeves 29 are fixedly connected to the two moving frames 25 respectively, and when the first lead screw 28 rotates, the two first threaded sleeves 29 move synchronously towards or in the opposite direction.

[0075] It can be seen from this that the movement drive of the two movable gear rollers 26 can be achieved by utilizing the spiral transmission between the first screw 28 and the two first threaded sleeves 29, wherein the first screw 28 can be driven by a motor or manually. When manual drive is adopted, a rotating handle is connected to one end of the first screw 28.

[0076] Furthermore, a first driving motor 251 is fixed on the outer wall of one side of any one of the movable frames 25, and a corresponding movable gear roller 26 includes an inner roller 261 and an outer roller 262 that can rotate relative to each other, the inner roller 261 is driven to rotate by the first driving motor 251, and at least one mounting groove is arranged in an array on the outer wall of the inner roller 261, an electric push rod 263 is installed in each mounting groove, and a limit block 264 that can engage with the inner wall of the outer roller 262 is fixed to the telescopic end of the electric push rod 263.

[0077] In summary

[0078] When the two movable toothed rollers 26 move toward each other, Figure 5As can be seen from the left figure, the electric push rod 263 drives the limit block 264 to separate from the outer roller 262, so that the corresponding inner roller 261 and the outer roller 262 can rotate relative to each other, and the two outer rollers 262 rotate in the opposite direction ( Figure 3 The left outer roller 262 rotates counterclockwise, and the right outer roller 262 rotates clockwise), thereby completing the movement without interfering with the inner roller 261 and the first drive motor 251 connected thereto.

[0079] When driving the front C arm 21 to rotate, Figure 5 As can be seen from the right figure, the electric push rod 263 pushes the limit block 264 to engage with the inner wall of the outer roller 262, so as to achieve the matching limitation between the inner roller 261 and the outer roller 262. In this state, the corresponding inner roller 261 is driven to rotate by the first drive motor 251, and then the outer roller 262 is driven to rotate. The outer roller 262 is directly engaged with the outer wall of the front C-arm 21, thereby effectively driving the front C-arm 21 to rotate.

[0080] Specific, combined Figure 6 It can be seen that regarding the front clamping mechanism 2, the following implementation structure is provided.

[0081] The rear clamping mechanism 3 comprises:

[0082] A rear mounting base 32 with an opening at the top;

[0083] A drive assembly rotatably disposed inside the rear mounting base 32; the drive assembly includes two drive gear rollers 33 arranged in sequence from top to bottom, the two drive gear rollers 33 are respectively meshed and connected with the inner and outer side walls of the rear C-arm 31, and the two drive gear rollers 33 include a driving gear roller and a driven gear roller;

[0084] A second driving motor 34 is fixed on an outer wall of one side of the rear mounting base 32 , and the active gear roller is driven to rotate by the second driving motor 34 .

[0085] As can be seen from the above, the driving principle of the rear C-arm 31 is: the second driving motor 34 drives the active gear roller of the two driving gear rollers 33 to rotate, and the active gear roller drives the rear C-arm 31 to rotate through meshing, and at the same time, the driven gear roller cooperates with the active gear roller to clamp the rear C-arm 31, thereby ensuring the stable positioning of the rear C-arm 31.

[0086] Furthermore, the mobile driving assembly in the rear clamping mechanism 3 includes:

[0087] A fixed base 35 with a slide groove on the top, and the other end of the traction mechanism 1 is connected to the outside of the fixed base 35;

[0088] Rotate the second lead screw 36 installed inside the fixed base 35;

[0089] At least one second threaded sleeve 37 is spirally sleeved on the second lead screw 36 . The second threaded sleeve 37 passes through the slide groove and is fixedly connected to the rear mounting base 32 .

[0090] It can be seen that the movement drive of the rear mounting base 32 and the rear C-arm 31 can be realized by utilizing the spiral transmission between the second lead screw 36 and the two second threaded sleeves 37, wherein the second lead screw 36 can be driven by a motor or manually. When manual drive is adopted, a rotating handle is connected to one end of the second lead screw 36.

[0091] In addition, scale marks are provided on the inner wall and / or side wall of the front C arm 21 and the rear C arm 31, and the scale marks are used to mark the current rotation angle of the front C arm 21 and the rear C arm 31. As can be seen from the above, regarding the observation of the scale marks, the limit gear roller 24 and the drive gear roller 33 can be used as the positioning reference, combined with Figure 3 and Figure 6 As shown in FIG. 1 , the scale value at the middle position of the C-arm is recorded as “0°”, and the values ​​on both sides are respectively “+N°” and “-N°”, where N is an arbitrary real number. Specifically, when the limit gear roller 24 and the drive gear roller 33 are respectively set at Figure 3 and Figure 6 When the position is shown, it indicates that the current rotation angles of the front C-arm 21 and the rear C-arm 31 are both 0°.

[0092] Although 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 the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An orthopedic surgery assisting device, characterized in that: It comprises a traction mechanism (1) arranged along the Y axis, and a front clamping mechanism (2) and a rear clamping mechanism (3) respectively connected to two ends of the traction mechanism (1); The traction mechanism (1) is used to adjust the traction distance between the front clamping mechanism (2) and the rear clamping mechanism (3); The front clamping mechanism (2) comprises a lifting drive assembly and a rotatable front C arm (21), and the lifting drive assembly is used to drive the front C arm (21) to lift and lower along the Z axis; the rear clamping mechanism (3) comprises a moving drive assembly and a rotatable rear C arm (31), and the moving drive assembly is used to drive the rear C arm (31) to move along the X axis; the front C arm (21) and the rear C arm (31) are both spirally penetrated with two symmetrically arranged positioning steel nails (4); The front clamping mechanism (2) comprises: A front mounting base (22) with an opening at the top, and one end of the traction mechanism (1) is connected to the outside of the front mounting base (22); A limit assembly is arranged inside the front mounting base (22) in a liftable manner; the limit assembly comprises two symmetrically arranged slides (23) and two limit gear rollers (24) rotatably mounted between the two slides (23); the two slides (23) are respectively slidably connected to the inner walls on both sides of the front mounting base (22); and the two limit gear rollers (24) are respectively meshedly connected to the inner and outer side walls of the front C-arm (21); The lifting drive assembly in the front clamping mechanism (2) comprises: Two movable frames (25) are movably arranged inside the front mounting base (22), the two movable frames (25) are symmetrically distributed on both sides of the limiting gear roller (24), and the two movable frames (25) move synchronously towards or in opposite directions; Rotating a movable toothed roller (26) mounted on the movable frame (25), wherein both movable toothed rollers (26) are meshedly connected with the outer side wall of the front C-arm (21); A first driving motor (251) is fixed on an outer wall of one side of any one of the movable frames (25), and a corresponding movable gear roller (26) includes an inner roller (261) and an outer roller (262) that can rotate relative to each other, the inner roller (261) being driven to rotate by the first driving motor (251), and at least one mounting groove is arranged in an array on the outer wall of the inner roller (261), an electric push rod (263) is installed in each of the mounting grooves, and a limit block (264) that can engage with the inner wall of the outer roller (262) is fixed at the telescopic end of the electric push rod (263).

2. An orthopedic surgery assisting device according to claim 1, characterized in that: A limit spring (27) is connected between the bottom of the slide seat (23) and the bottom wall of the front mounting base (22), and the limit spring (27) is used to press the front C arm (21) from top to bottom onto the movable gear roller (26).

3. The orthopedic surgery assisting device according to claim 1, characterized in that: The lifting drive assembly in the front clamping mechanism (2) further comprises: Rotating a first lead screw (28) mounted inside the front mounting base (22); Two first threaded sleeves (29) are spirally sleeved on the first lead screw (28); the two first threaded sleeves (29) are respectively fixedly connected to two moving frames (25), and when the first lead screw (28) rotates, the two first threaded sleeves (29) move synchronously towards or in opposite directions.

4. The orthopedic surgery assisting device according to claim 1, characterized in that: The rear clamping mechanism (3) comprises: A rear mounting base (32) with an opening at the top; A drive assembly rotatably arranged inside the rear mounting base (32); the drive assembly comprises two drive gear rollers (33) arranged in sequence from top to bottom, the two drive gear rollers (33) are respectively meshed and connected with the inner and outer side walls of the rear C-arm (31), and the two drive gear rollers (33) comprise a driving gear roller and a driven gear roller; A second drive motor (34) is fixed on an outer wall of one side of the rear mounting base (32), and the active gear roller is driven to rotate by the second drive motor (34).

5. The orthopedic surgery assisting device according to claim 4, characterized in that: The mobile driving assembly in the rear clamping mechanism (3) comprises: A fixed base (35) with a slide groove on the top, and the other end of the traction mechanism (1) is connected to the outside of the fixed base (35); Rotating a second lead screw (36) installed inside the fixed base (35); At least one second threaded sleeve (37) is spirally sleeved on the second lead screw (36); the second threaded sleeve (37) passes through the slide groove and is fixedly connected to the rear mounting base (32).

6. The orthopedic surgery assisting device according to claim 1, characterized in that: Scale marks are provided on the inner wall and / or the side wall of the front C arm (21) and the rear C arm (31), and the scale marks are used to mark the current rotation angles of the front C arm (21) and the rear C arm (31).

7. The orthopedic surgery assisting device according to claim 1, characterized in that: The traction mechanism (1) comprises: A traction outer rod (11) is provided with a cavity inside, and a threaded column (12) is rotatably mounted on a side wall of the traction outer rod (11); An inner traction rod (13) is slidably fitted in the cavity of the outer traction rod (11), a thread groove (14) is provided on one side wall of the inner traction rod (13), and one side of the threaded column (12) is screwed into the inside of the thread groove (14) and the other side is limited to the outside of the outer traction rod (11).

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