Guided Adjustable Longitudinal Bone Transport Device

Abstract

This invention discloses a guided and adjustable longitudinal bone transport device, comprising a main rod, a fixing pin, an embedded slider, and a moving pin. The main rod has a threaded section in its middle, with a strip-shaped sliding hole in the middle of the threaded section. The embedded slider is fitted inside the strip-shaped sliding hole. An adjusting sleeve is fitted outside the threaded section, connecting to the embedded slider. The embedded slider body includes at least two through holes, each fitted with a screw. One screw includes an upper threaded section and a lower self-tapping section. The two ends of the threaded section of the screw are respectively fitted with clamping screws, which press against the upper and lower surfaces of the corresponding through holes. This invention can control the transport direction while continuously controlling the transport. Because the adjusting sleeve is on the threaded section of the main rod, turning the adjusting sleeve can drive the embedded slider to move, thereby driving the bone end to move forward axially.

Description

Technical Field

[0001] This invention belongs to the field of bone transport device technology, specifically relating to a longitudinal bone transport device capable of guiding and adjusting direction. Background Technology

[0002] Current bone transport surgeries require long-term external fixation for at least two years to ensure rigidity and prevent fractures in newly formed bone. However, long-term external fixation not only restricts movement but also easily leads to joint stiffness, pin tract infection, and secondary osteomyelitis. Many patients have to discontinue treatment due to these serious complications.

[0003] Large-segment bone defects in long bones refer to fractures that cannot heal spontaneously or can only regenerate 110% of their original size, typically affecting 2-3 times the diameter of the long bone. These defects are usually caused by high-energy trauma, infection, tumors, etc., and are often accompanied by limb shortening, deformities, osteomyelitis, muscle atrophy, and stiffness in adjacent joints. Repairing and correcting these defects is one of the greatest challenges in orthopedics. External fixation involves osteotomy at the proximal or distal end of the defect, with the free bone segment transported to the defect site. Bone lengthening, or distraction osteogenesis, involves cutting the bone while preserving soft tissue and blood supply, fixing both ends with a specialized traction device, and gradually applying tension using the tensile stress principle to slowly pull the bone segment, continuously stimulating the body's tissues and activating their regenerative potential, allowing new bone to form between the osteotomy sites, thus achieving bone regeneration. Existing external fixation structures used for bone transport and lengthening are unstable and pose a risk of angular deformities. Intramedullary nails used for bone lengthening require complex mechanical structures or external energy.

[0004] Large bone defects cause enormous physical and psychological harm and economic burden to patients, so how to solve this problem has become an important issue in the field of orthopedics.

[0005] Existing devices used for longitudinal bone transport cannot adjust direction during the transport process, leading to inaccurate alignment of the bone ends in the later stages of transport. Because bone transport treatment is lengthy, discovering misalignment of the bone ends later can result in secondary surgeries or even lifelong bone deformities.

[0006] Since the main shaft is a single unit, two fixation screws are needed at each end to penetrate the muscle tissue and extend into the bone for fixation. During the process of at least four fixation screws penetrating the muscle tissue, it is necessary to consider avoiding blood vessels and nerve tissue. Existing similar products either cannot effectively avoid these tissues or use clips located at the ends and middle to hold the fixation screws, making the assembly and adjustment of the proximal and distal fixation screws cumbersome. A second scenario is exemplified by a device for bone transport and lengthening using an intramedullary-extramedullary combination method, disclosed in CN206964671 U. This device includes an external fixator, a pressure traction device, bone pins, and an intramedullary nail. The pressure traction device is mounted on the external fixator, the intramedullary nail extends into the medullary cavity, the external fixator and the intramedullary nail are arranged parallel to each other, and the bone pins pass through the external fixator and the intramedullary nail. The intramedullary nail has a nail body with bone pin holes at the proximal and distal ends to facilitate bone pin passage. A bone pin movement groove extending along the elongation direction of the nail body is located between the proximal and distal ends. Multiple locking holes are located at the proximal end, distal end, and between the proximal and distal ends of the nail body. The intramedullary-extramedullary combined device for bone transport and lengthening of this invention has a stable structure, but it is inconvenient to use. The assembly and disassembly of the external fixator are troublesome before and after bone transport and lengthening surgery. Furthermore, it has many components, requiring separate installation and adjustment of multiple fixation pins. The fixed spacing and orientation of adjacent fixation pins make it impossible to effectively avoid potentially encountered blood vessels, nerves, and other tissues. This solution, and similar products in the field, generally cannot adjust the transport state at any time, nor can they correct the transport direction during the transport process. Summary of the Invention

[0007] In response to the common problem in existing similar products that directional deviation easily occurs during longitudinal transport of bone ends, leading to inaccurate docking, this invention provides a guided and adjustable longitudinal bone transport device that can control the transport direction while continuously controlling the transport.

[0008] The solution adopted by this invention to solve its technical problem is as follows: a guided and adjustable longitudinal bone transport device, including a main rod, a fixing pin, an embedded slider, and a moving pin. The main rod has a threaded section in the middle, and a strip-shaped sliding hole in the middle of the threaded section. An embedded slider is fitted inside the strip-shaped sliding hole. At the same time, an adjusting sleeve is fitted outside the threaded section. The adjusting sleeve is connected to the embedded slider, so that rotating the adjusting sleeve can drive the embedded slider to translate axially. The embedded slider body includes at least two through holes, each fitted with a screw. One screw includes a threaded section at the upper part and a self-tapping section at the lower part. The two ends of the threaded section of the screw are respectively installed with clamping wires and press against the upper and lower surfaces of the corresponding through holes. The other screw includes at least a self-tapping section at the lower part. The screw is fitted in the corresponding through hole and can slide freely axially.

[0009] The assembly relationship of each component is as follows: the embedded slider is fitted into the strip-shaped sliding hole and can slide left and right; the direction adjustment screw and the adaptive sliding screw are respectively fitted into the direction adjustment hole and the free hole; the two ends of the threaded section of the direction adjustment screw are respectively equipped with clamping wires and press against the upper and lower surfaces of the corresponding through holes; since the embedded slider has plates attached to the upper and lower ends respectively, the upper and lower clamping wires press against the upper side of the upper plate and the lower side of the lower plate respectively, and the upper and lower clamping wires press against each other to fix the upper and lower plates to the upper and lower sides of the embedded slider.

[0010] The spindle has shaft holes at both ends of the spindle, and each shaft hole is fitted with an adjustable end piece. Each adjustable end piece has an adjustment hole through it, and each adjustment hole has an adjustable pin fixed inside it. The main body has through-holes at both ends, and each hole contains a fixing screw. Each fixing screw includes a self-tapping section at the lower end and a threaded section at the upper end. The fixing hole contains a nut section, and the fixing screw is fixed to the fixing hole by connecting the threaded section and the nut section. However, other fixing methods are not excluded.

[0011] Each adjusting pin includes a self-tapping screw section at the lower end and a threaded section at the upper end. The adjusting hole includes a nut section. The adjusting pin is connected to the nut section through the threaded section to achieve fixation with the adjusting hole, but other fixing methods are not excluded.

[0012] The threaded section with a larger diameter in the middle of the main rod has milled planes on the upper and lower sides, retaining the threaded parts on the left and right sides, and a strip-shaped sliding hole running along the axial direction passes through between the upper and lower milled planes.

[0013] The embedded slider is a rectangular body with plates fixed on its upper and lower sides. The width of the upper and lower plates is greater than the width of the rectangular body. The width of the rectangular body is the same as the width of the strip-shaped sliding hole. The width of the upper and lower plates is greater than the width of the strip-shaped sliding hole. Thus, after the embedded slider is fitted into the strip-shaped sliding hole, the upper and lower plates can form a constraint relationship to prevent the embedded slider from falling out of the strip-shaped sliding hole.

[0014] The embedded slider body is provided with a slider pin hole, a free hole and a directional adjustment hole in sequence. The adjusting screw sleeve body is a threaded sleeve with an annular groove on the inner side of one end, and the annular groove is provided with an assembly hole.

[0015] The lower end of the directional adjustment screw and the adaptive sliding screw has a self-tapping section for penetrating into the bone, and the upper end has a threaded section for connecting to the main rod. The upper end also has an anti-rotation plane. The adaptive sliding screw is fitted into the free hole and can slide freely along the axis. The adaptive sliding screw is not locked or constrained. The self-tapping section at its lower end is screwed into the bone, and its upper section can slide freely in the free hole.

[0016] The upper ends of the directional adjusting screw and the adaptive sliding screw are respectively provided with anti-rotation planes, so there are corresponding anti-rotation planes in the directional adjusting hole and the free hole, so that the directional adjusting screw and the adaptive sliding screw are respectively fitted into the directional adjusting hole and the free hole, and can only move along the axial direction without rotating.

[0017] A through pin is fitted inside the slider pin hole of the embedded slider. The length of the through pin is not greater than the diameter of the annular groove, but the diameter of the through pin is greater than the inner diameter of the adjusting screw sleeve. After the through pin is fixed in the appropriate position of the slider pin hole of the embedded slider, the adjusting screw sleeve can rotate and drive the through pin and the embedded slider to move together. When the adjusting screw sleeve is turned to the left or right, it drives the embedded slider to move to the left or right. After the turning action is stopped, the embedded slider will not move.

[0018] The axis of the main shaft is determined to be parallel to the axes of the distal and proximal bones, meaning their projections are consistent. The distal fixation pins and adjustment pins are grouped together, the proximal fixation pins and adjustment pins are grouped together, and the directional adjustment screw and adaptive sliding screw in the middle are grouped together. All three groups are on the same straight line (passing through the axis of the main shaft and perpendicular to the main shaft respectively). Therefore, during transportation, there is no need to consider the issue of left-right changes in the transported bone ends.

[0019] The beneficial effects of this invention are: it enables control of the transport direction while continuously controlling the transport process. Because the adjusting sleeve is mounted on the threaded section of the main rod, turning the adjusting sleeve moves the embedded slider, thereby causing the bone end to move forward axially. During each movement, the direction of movement is adjusted continuously to avoid the problem of mismatch between the distal and proximal bone ends in the later stages of the movement.

[0020] When using this invention, first rotate the nails to the appropriate positions and insert them into the fixed positions. Then, pull and rotate the adjusting end outwards to select a suitable nailing position that avoids blood vessels and nerve tissue. Finally, insert the adjusting nails into the fixed positions.

[0021] In this invention, both the fixing nail and the adjusting nail are fixed together with the corresponding through hole of the main rod through the threaded section at the upper end, without the need to add a bulky fixing node, and the installation and fixing method is simple and convenient. Attached Figure Description

[0022] Figure 1 This is a three-dimensional view of a structure of the present invention.

[0023] Figure 2 yes Figure 1 Longitudinal cross-sectional view.

[0024] Figure 3 yes Figure 1 The left view.

[0025] Figure 4 These are views of the main rod from various angles.

[0026] Figure 5 This is a structural diagram of the embedded slider.

[0027] Figure 6 This is a structural diagram of the direction adjustment pin.

[0028] Figure 7 This is a structural diagram of a threaded sleeve.

[0029] Figure 8 yes Figure 7 Cross-sectional view of the middle CC section.

[0030] Figure 9 yes Figure 7 Cross-sectional view of DD.

[0031] Figure 10 yes Figure 2 Enlarged structural diagram of section E in the middle.

[0032] Figure 11 yes Figure 2 Enlarged structural diagram of the middle F section.

[0033] The following are the labels in the diagram: Main rod 1, threaded rod segment 2, strip-shaped sliding hole 3, adjusting screw sleeve 4, embedded slider 5, slider pin hole 6, free hole 7, directional adjustment hole 8, through pin 9, milled plane 10, stacked plate 11, head end assembly hole 12, fixing hole 13, adjusting hole 14, fixing pin 15, adaptive adjusting pin 16, adaptive adjusting end 17, shaft 18, shaft hole 19, directional adjusting screw 20, adaptive sliding screw 21, anti-rotation plane 22, self-tapping screw segment 23, threaded segment 24, clamping screw 25. Detailed Implementation

[0034] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0035] Example 1: A kind of Figure 1 and Figure 2 The guided and adjustable longitudinal bone transport device shown can be adjusted inward or outward at any time during the longitudinal transport of the proximal bone end, guiding and continuously adjusting the transport direction to always ensure that the bone end moves forward in the accurate direction.

[0036] Specifically, such as Figure 1 and Figure 2 As shown, a main rod serves as the main body of the outer frame, with a threaded rod segment 2 in the middle with an increased diameter. The threaded rod segment 2 has a strip-shaped sliding hole 3 in the middle, and an embedded slider 5 is fitted inside the strip-shaped sliding hole 3. At the same time, an adjusting screw sleeve 4 is fitted on the outside of the threaded rod segment 2. The adjusting screw sleeve 4 is connected to the embedded slider 5, so that rotating the adjusting screw sleeve 4 can drive the embedded slider 5 to translate axially.

[0037] Among them, main rod 1, as Figure 4 As shown, the upper and lower sides of the threaded rod segment 2 with the increased diameter in the middle are milled planes, while the threaded portions on the left and right sides are retained. A strip-shaped sliding hole 3 runs through between the upper and lower milled planes along the axial direction.

[0038] Embedded slider 5 Figure 5 As shown, the entire structure is rectangular, with plates 11 fixed to its upper and lower sides respectively. The width of the upper and lower plates 11 is greater than the width of the rectangular structure. The width of the rectangular structure is the same as the width of the strip-shaped sliding hole 3. The width of the upper and lower plates 11 is greater than the width of the strip-shaped sliding hole 3. Therefore, after the embedded slider is fitted into the strip-shaped sliding hole, the upper and lower plates can form a constraint relationship to prevent the embedded slider 5 from detaching from the strip-shaped sliding hole 3.

[0039] Figure 5 It can also be seen that the main body is sequentially provided with a slider pin hole 6, a free hole 7, and a direction adjustment hole 8.

[0040] Adjusting screw sleeve 4 Figures 7-9 As shown, its main body is a threaded sleeve, with an annular groove 26 on the inner side of one end, and an assembly hole 27 is provided in the annular groove.

[0041] Direction adjusting screw 20 and adaptive sliding screw 21 as follows Figure 6 As shown, the lower end of the rod has a self-tapping section 23 for penetrating the bone, the upper end has a threaded section 24 for connecting the main rod, and the upper end also has an anti-rotation plane 22.

[0042] like Figure 2 As shown, the assembly relationship of each component is as follows: the embedded slider 5 is fitted into the strip-shaped sliding hole 3 and can slide left and right; the direction adjustment screw 20 and the adaptive sliding screw 21 are respectively fitted into the direction adjustment hole 8 and the free hole 7; the two ends of the threaded section 24 of the direction adjustment screw 20 are respectively equipped with clamping wires 25 and press against the upper and lower surfaces of the corresponding through holes; since in this embodiment, the upper and lower clamping wires 25 are respectively pressed against the upper side of the upper clamping wire and the lower side of the lower clamping wire, and the upper and lower clamping wires 25 press against each other to fix the upper and lower clamping wires to the upper and lower sides of the embedded slider.

[0043] The adaptive sliding screw 21 is fitted into the free hole 7 and can slide freely along the axis. The adaptive sliding screw 21 is not locked or constrained. Its lower end self-tapping section 23 is screwed into the bone, and its upper section can slide freely in the free hole 7.

[0044] Since the upper ends of the directional adjusting screw 20 and the adaptive sliding screw 21 are respectively provided with anti-rotation planes 22, there are corresponding anti-rotation planes (or key and keyway cooperation) in the directional adjusting hole 8 and the free hole 7, so that the directional adjusting screw 20 and the adaptive sliding screw 21 are respectively fitted into the directional adjusting hole 8 and the free hole 7, and can only move along the axial direction without rotating.

[0045] Figure 2 It can also be seen that a through pin 9 is fitted inside the slider pin hole 6 of the embedded slider. The length of the through pin 9 is not greater than the diameter of the annular groove 26, but the diameter of the through pin 9 is greater than the inner diameter of the adjusting screw sleeve 4. Therefore, after the through pin 9 is fitted into the appropriate position of the slider pin hole of the embedded slider, as... Figure 2 As shown, this allows the adjusting screw sleeve 4 to rotate, causing the through pin and the embedded slider to move together. When the adjusting screw sleeve 4 is turned to the left or right, it causes the embedded slider to move to the left or right. After the turning action is stopped, the embedded slider will not move.

[0046] Figure 1 and Figure 2 It can also be seen that there are through fixing holes 13 at both ends of the main body of the main rod 1, and fixing nails 15 are fixed in each fixing hole. Figure 2 As can be seen, each fixing pin includes a self-tapping section at the lower end and a threaded section 151 at the upper end, such as... Figure 11 As shown, the fixing hole 13 includes a nut section 171. The fixing pin 15 is connected to the nut section 171 through the threaded section 151 to achieve fixing with the fixing hole 13, but other fixing methods are not excluded.

[0047] Figure 2 and Figure 4 As can be seen, there are shaft holes 19 at both ends of the spindle 1, and each shaft hole is fitted with an adaptive adjustment end 17. Each adaptive adjustment end 17 has an adjustment hole 14 through it, and each adjustment hole 14 has an adaptive adjustment pin 16 fixed inside it. Figure 2 As can be seen, each adjusting pin includes a self-tapping section at the lower end and a threaded section 151 at the upper end, as shown below. Figure 11 As shown, the adjusting hole 14 includes a nut section 171. The adjusting pin 16 is connected to the nut section 171 through the threaded section 151 to achieve fixation with the adjusting hole 14, but other fixing methods are not excluded.

[0048] In use, the two fixing screws and the adjusting screw located at both ends of the main rod are respectively driven into the bone of the distal and proximal bones. The direction adjusting screw 20 and the adaptive sliding screw 21 are respectively screwed into the bone of the moving bone. The driving sequence of each fixing screw and adjusting screw is as follows: first, the fixing screw 15 (first screw) is driven into the appropriate position by rotating it. Then, the adaptive adjusting end 17 is pulled outward and rotated to select a suitable driving position that avoids blood vessels and nerve tissue. Finally, the adaptive adjusting screw 16 (second screw) is driven into the device.

[0049] In this embodiment, the upper or lower clamping wire 25 can be screwed on at any time during femoral transport. For example, loosening the lower adjustment wire and screwing on the upper adjustment wire can move the bone end outward, while loosening the upper adjustment wire and screwing on the lower adjustment wire can move the bone end inward. After the direction is adjusted to the correct position, the upper and lower clamping wires are screwed on to fix the position.

[0050] Since the adjusting sleeve 4 is attached to the threaded section 2 of the main rod, turning the adjusting sleeve 4 can move the embedded slider, thereby causing the bone end to move forward axially. During each movement, the direction of movement is adjusted at any time to avoid the problem of mismatch between the distal and proximal bone ends in the later stages of movement.

[0051] It should be noted that when using this device, the axis of the main shaft is made parallel to the axes of the distal and proximal bones, meaning their projections are consistent. The distal fixation pins and adjustment pins form one group, the proximal fixation pins and adjustment pins form another group, and the central direction adjustment screw 20 and adaptive sliding screw 21 form a third group. All three groups are on the same straight line (passing through the axis of the main shaft and perpendicular to it), so that during transport, there is no need to consider the left-right changes of the transported bone ends.

[0052] In this embodiment, both the fixing pin and the adjusting pin are fixed together with the corresponding through hole of the main rod through the threaded section at the upper end, without the need to add a bulky fixing node, making the installation and fixing method simple and convenient.

[0053] Example 2: Based on Example 1, the embedded slider is equipped with a self-locking structure. For example, one way is to set the front end of the embedded slider, i.e. the traction end, as a two- or multi-lobed structure that expands outward. In its natural state, the expanded part can be supported on the inner wall of the strip-shaped sliding hole (the inner wall of the strip-shaped sliding hole is smooth or has friction texture). The outer side of the front end of the expanded part has a conical surface, and the rear side wall of the annular groove of the adjusting screw sleeve has a corresponding conical surface. When the adjusting screw sleeve 4 is rotated, the two conical surfaces match and slide relative to each other, causing the traction end of the embedded slider 5 to contract, thereby enabling axial movement and adjustment. Otherwise, the traction end of the embedded slider 5 expands outward, forming a self-locking relationship.

[0054] It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of the present invention and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of the present invention should be included within the protection scope of the present invention.

Claims

1. A guided and adjustable longitudinal bone transport device, comprising a main rod (1), a fixing pin (15), an embedded slider (5), and a movable pin, characterized in that, The main rod (1) has a threaded rod section (2) in the middle, and a strip-shaped sliding hole (3) in the middle of the threaded rod section (2). An embedded slider (5) is fitted inside the strip-shaped sliding hole (3). At the same time, an adjusting screw sleeve (4) is fitted outside the threaded rod section (2). The adjusting screw sleeve (4) is connected to the embedded slider (5). Thus, rotating the adjusting screw sleeve (4) can drive the embedded slider (5) to translate along the axial direction. The embedded slider (5) has a slider pin hole (6), a free hole (7) and an adjustment hole (8) arranged sequentially on its main body; The movable nail includes a direction adjusting screw (20) and an adaptive sliding screw (21); The lower end of the rod of the direction adjusting screw (20) and the adaptive sliding screw (21) has a self-tapping section (23) for penetrating into the bone, and the upper end has a first thread section; The direction adjustment screw (20) is fitted into the direction adjustment hole (8). The two ends of its first thread section are respectively fitted with clamping wires (25) and press against the upper and lower surfaces of the direction adjustment hole (8). By turning the upper and lower clamping wires (25) respectively, the direction adjustment screw (20) can be driven to actively extend or retract relative to the embedded slider (5). The adaptive sliding screw (21) is fitted inside the free hole (7) and is not locked or constrained, allowing it to slide freely along the axial direction.

2. The guided and adjustable longitudinal bone transport device according to claim 1, characterized in that, The main rod (1) has shaft holes (19) at both ends of the axial position. Each shaft hole is fitted with an adjustment end (17). Each adjustment end (17) has an adjustment hole (14) through it. Each adjustment hole (14) has an adjustment pin (16) fixed inside it.

3. The guided and adjustable longitudinal bone transport device according to claim 1, characterized in that, The main body (1) has through fixing holes (13) at both ends. Each fixing hole is fixed with a fixing nail (15). Each fixing nail includes a self-tapping screw section at the lower end and a second thread section at the upper end. The fixing hole (13) includes a nut section (171). The fixing nail (15) is connected to the nut section (171) through the second thread section to achieve fixation with the fixing hole (13).

4. The guided and adjustable longitudinal bone transport device according to claim 2, characterized in that, Each adjusting pin includes a self-tapping screw section at the lower end and a third thread section at the upper end. The adjusting hole (14) includes a nut section (171). The adjusting pin (16) is connected to the nut section (171) through the third thread section to achieve fixation with the adjusting hole (14).

5. The guided and adjustable longitudinal bone transport device according to claim 1, characterized in that, The main rod (1) has a threaded rod section (2) with a larger diameter in the middle. The upper and lower sides have milled planes, and the threaded parts on the left and right sides are retained. A strip-shaped sliding hole (3) runs through between the upper and lower milled planes along the axial direction.

6. The guided and adjustable longitudinal bone transport device according to claim 1, characterized in that, The embedded slider (5) is a rectangular body with a plate (11) fixed on its upper and lower sides respectively. The width of the upper and lower plates (11) is greater than the width of the rectangular body. The width of the rectangular body is the same as the width of the strip-shaped sliding hole (3). The width of the upper and lower plates (11) is greater than the width of the strip-shaped sliding hole (3). Thus, after the embedded slider is fitted into the strip-shaped sliding hole, the upper and lower plates can form a constraint relationship to prevent the embedded slider (5) from falling out of the strip-shaped sliding hole (3).

7. The guided and adjustable longitudinal bone transport device according to claim 1, characterized in that, The upper ends of the directional adjusting screw (20) and the adaptive sliding screw (21) are respectively provided with anti-rotation planes (22). There are corresponding anti-rotation planes in the directional adjusting hole (8) and the free hole (7), so that when the directional adjusting screw (20) and the adaptive sliding screw (21) are respectively fitted into the directional adjusting hole (8) and the free hole (7), they can only move along the axial direction and cannot rotate.

8. The guided and adjustable longitudinal bone transport device according to claim 1, characterized in that, A through pin (9) is fitted inside the slider pin hole (6) of the embedded slider. The length of the through pin (9) is not greater than the diameter of the annular groove (26), but the diameter of the through pin (9) is greater than the inner diameter of the adjusting sleeve (4). After the through pin (9) is fitted into the appropriate position of the slider pin hole of the embedded slider, the adjusting sleeve (4) can rotate and drive the through pin and the embedded slider to move together. When the adjusting sleeve (4) is turned to the left or right, the embedded slider is driven to move to the left or right. After the turning action is stopped, the embedded slider will not move.

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