Covered stent and delivery device

Abstract

The present application belongs to the technical field of interventional medical instruments, and particularly relates to a covered stent and a delivery device. The covered stent comprises a stent body, a cover and at least one clamping unit. The cover is arranged on the stent body, and the clamping unit is arranged inside the stent body provided with the cover. The clamping unit can be clamped on the delivery device for delivering the covered stent. According to the covered stent, the delivery process of the covered stent can be realized, and the clamping unit will not cause damage to the blood vessel wall due to the outward force generated by the release of the covered stent, thereby ensuring the safety and reliability of the operation process and preventing unnecessary damage to the patient.

Description

Technical Field

[0001] This invention belongs to the field of interventional medical device technology, specifically relating to a covered stent and delivery device. Background Technology

[0002] Aneurysm is a common vascular disease in clinical practice, and it often occurs in the elderly. This disease can easily lead to the rupture of aortic aneurysm, posing a great threat to the patient's life.

[0003] With the continuous development of modern medical technology, minimally invasive surgery has been used to implant covered stents into the body for the treatment of aortic aneurysms and dissecting aneurysms. Due to its minimal trauma and rapid recovery, it has gained widespread application. This treatment method involves compressing the covered stent into a delivery device, guiding it along a pre-implanted guidewire into the body. Once it reaches the lesion site, the covered stent is released to isolate the lesion and reconstruct the blood flow channel. After the aneurysm and dissection lose their blood supply, the remaining blood in the aneurysm cavity gradually thrombus and myovascular tissue. The dilated aneurysm wall contracts under pressure, gradually returning to a near-original state, thereby achieving the goal of treating aneurysms and dissections.

[0004] Current endovascular stent graft systems used for thoracic aortic aneurysms and dissecting aneurysms consist of a delivery system and a endovascular stent graft. The delivery system typically comprises a sheath core, a sheath tube, and a handle, while the endovascular stent graft consists of a metal skeleton and a endovascular graft. The endovascular stent graft is pre-loaded into the sheath tube of the delivery system. To achieve precise positioning of the endovascular stent graft, the sheath core is typically used to fix the tip of the stent graft. The sheath core is then detached after the stent graft has been completely released from the sheath tube. Alternatively, to ensure the tip of the endovascular stent graft is fixed to the delivery system, an un-capped metal skeleton is usually attached to the tip of the stent graft, and the delivery system is fixed to this uncapped metal skeleton. However, this presents a problem. Because the metal skeleton at the tip of the endovascular stent graft is released last, a significant outward expansion force is generated at the moment of release. This outward expansion force acts on the vessel wall, causing damage and, in severe cases, creating new ruptures, leading to surgical failure. Summary of the Invention

[0005] The objective of this invention is to at least address the problem of damage to the blood vessel wall caused by covered stents during deployment. This objective is achieved through the following means:

[0006] A first aspect of the present invention provides a coated stent, the coated stent comprising:

[0007] Support body;

[0008] A film is applied to the support body;

[0009] At least one snap-fit ​​unit is located inside the support body on which the film is provided, and the snap-fit ​​unit is capable of snapping onto a conveyor for conveying the film-covered support.

[0010] According to the covered stent of the present invention, by providing a snap-fit ​​unit inside the covered stent body, the snap-fit ​​unit snaps onto the delivery device for delivering the covered stent during the delivery process of the covered stent, thereby realizing the delivery process of the covered stent. Since the snap-fit ​​unit is inside the stent body, the snap-fit ​​unit will not come into contact with the blood vessel wall. After the covered stent completes the delivery process, the connection between the stent and the delivery device is released. After the covered stent is completely released from the delivery device, the snap-fit ​​unit will not cause damage to the blood vessel wall due to the outward force generated by the release of the covered stent, thereby ensuring the safety and reliability of the surgical procedure and preventing unnecessary damage to the patient.

[0011] In addition, the covered stent according to the present invention may also have the following additional technical features:

[0012] In some embodiments of the present invention, the bracket body includes at least one metal wavering, the snap-fit ​​unit includes a limiting member and a connecting member, one end of the connecting member is connected to the metal wavering or the coating, and the other end of the connecting member is connected to the limiting member.

[0013] In some embodiments of the present invention, the minimum radial dimension of the limiting member is greater than the maximum radial dimension of the connecting member, and the limiting member includes a spherical structure, a disc-shaped structure, a polyhedral structure, or an irregular structure.

[0014] In some embodiments of the present invention, the limiting member includes a strip-shaped structure, an arc-shaped structure, a spiral structure, a wave-shaped structure, or a zigzag structure, and the connection point between the connecting member and the limiting member is at a position other than the two ends of the limiting member.

[0015] In some embodiments of the present invention, the connector includes a strip structure, an arc structure, a spiral structure, a wavy structure, or a zigzag structure.

[0016] Another aspect of the present invention provides a conveyor for conveying the aforementioned film-coated support, the conveyor comprising:

[0017] A first sheath core has at least one protrusion on its outer peripheral wall. The protrusion includes a first part, one end of which is connected to the first sheath core. The first part has a first through hole that extends through the other end of the first part. The snap-fit ​​unit passes through the first through hole from the other end of the first part to axially fix the snap-fit ​​unit.

[0018] In some embodiments of the present invention, the protrusion further includes a second portion, which is connected to the first portion. The second portion has a free end and a second through hole that penetrates the free end. The second through hole and the first through hole are interconnected. The snap-fit ​​unit passes through the second through hole and the first through hole from the free end, and the second portion radially fixes the snap-fit ​​unit.

[0019] In some embodiments of the present invention, the snap-fit ​​unit includes a limiting member and a connecting member connected to each other. The minimum radial dimension of the limiting member is greater than the maximum value of the maximum width of the first through hole and the maximum width of the second through hole, and the maximum radial dimension of the connecting member is less than the minimum value of the minimum width of the first through hole and the minimum width of the second through hole.

[0020] In some embodiments of the present invention, the snap-fit ​​unit includes a limiting member and a connecting member connected to each other. When the limiting member includes a strip-shaped structure, an arc-shaped structure, a spiral structure, a wave-shaped structure, or a zigzag structure, and the connection point between the connecting member and the limiting member is at any position of the limiting member other than the two ends of the limiting member, the length of the limiting member is greater than the maximum value of the maximum width of the first through hole and the maximum width of the second through hole, and the maximum radial dimension of the connecting member is less than the minimum value of the minimum width of the first through hole and the minimum width of the second through hole.

[0021] In some embodiments of the present invention, the conveyor further includes a second sheath core, the first sheath core being sleeved on the outside of the second sheath core, and the outer peripheral wall of the second sheath core being provided with at least one boss corresponding to the free end of the protrusion, the free end of the protrusion being able to abut against the boss. Attached Figure Description

[0022] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. Wherein:

[0023] Figure 1 This is a partial structural diagram of the film-coated stent according to Embodiment 1;

[0024] Figure 2 for Figure 1 A schematic diagram of the AA cross-sectional structure of the membrane-covered stent;

[0025] Figure 3 This is a partial structural diagram of the conveyor according to Embodiment 1;

[0026] Figure 4 for Figure 3 A schematic diagram of the partial connection structure between the first sheath core and the snap-fit ​​unit;

[0027] Figure 5 This is a partial structural diagram of the film-coated scaffold according to Embodiment 2;

[0028] Figure 6 for Figure 5 Schematic diagram of the BB cross-sectional structure of the membrane-covered stent;

[0029] Figure 7 This is a partial structural diagram of the first sheath core of the conveyor in Embodiment 3;

[0030] Figure 8 This is a partial structural diagram of the second sheath core of the conveyor in Embodiment 3;

[0031] Figure 9 This is a partial structural diagram of the first sheath core being sleeved outside the second sheath core in Embodiment 3;

[0032] Figure 10 This is a schematic diagram of the portion of the snap-fit ​​unit in Embodiment 3 snapping into the closed locking cavity. Detailed Implementation

[0033] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the invention and to fully convey the scope of the invention to those skilled in the art.

[0034] It should be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “described” as used herein may also include the plural forms. The terms “comprising,” “including,” “containing,” and “having” are inclusive and therefore indicate the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not construed as requiring them to be performed in a particular order described or illustrated unless the order of performance is explicitly indicated. It should also be understood that additional or alternative steps may be used.

[0035] Although terms such as first, second, third, etc., may be used in this document to describe multiple elements, components, regions, layers, and / or segments, these elements, components, regions, layers, and / or segments should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or segment from another. Unless the context clearly indicates otherwise, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence. Therefore, the first element, component, region, layer, or segment discussed below may be referred to as the second element, component, region, layer, or segment without departing from the teachings of the exemplary embodiments.

[0036] For ease of description, spatial relative terms may be used in the text to describe the relationship of one element or feature relative to another element or feature, as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "below," "above," "over," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure. For example, if the device in the figure is flipped, an element described as "below other elements or features" or "below other elements or features" would subsequently be oriented as "above other elements or features" or "above other elements or features." Therefore, the example term "below" can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions), and the spatial relative descriptors used in the text will be interpreted accordingly.

[0037] To more clearly describe the structure of this application, the terms "proximal" and "distal" are used herein as conventional terms in the field of interventional medicine. Specifically, "distal" refers to the end furthest from the operator during the surgical procedure, "proximal" refers to the end closest to the operator during the surgical procedure, "axial" refers to its length direction, and "radial" refers to the direction perpendicular to the "axial".

[0038] Implementation Method 1

[0039] Combination Figure 1 and Figure 2 As shown, the film-coated support 10 of this embodiment includes a support body 11, a film 12 and at least one snap-fit ​​unit 13. The support body 11 includes at least one metal bellows 111. The film 12 is disposed on the support body 11. At least one snap-fit ​​unit 13 is located inside the support body 11 with the film 12. The snap-fit ​​unit 13 can snap onto the conveyor used to transport the film-coated support 10.

[0040] According to this embodiment, the covered stent 10 has a snap-fit ​​unit 13 disposed inside the stent body 11 with a covering 12. During the delivery of the covered stent 10, the snap-fit ​​unit 13 is snapped onto the delivery device for delivering the covered stent 10, thereby realizing the delivery process of the covered stent 10. Since the snap-fit ​​unit 13 is located inside the stent body 11 with a covering 12, the snap-fit ​​unit 13 will not come into contact with the blood vessel wall. When the covered stent 10 completes the delivery process, the connection between it and the delivery device is released. During the process of the covered stent 10 being completely released from the delivery device, the snap-fit ​​unit 13 will generate an outward force as the covered stent 10 is released. This force will not cause damage to the blood vessel wall, thereby ensuring the safety and reliability of the surgical procedure and preventing unnecessary damage to the patient.

[0041] Specifically, in this embodiment, the membrane 12 is made of a biocompatible material, such as ePTFE (porous polytetrafluoroethylene), PTFE (polytetrafluoroethylene), PET (polyterephthalic acid), or PE (polyethylene). The metal corrugated coil 111 is cylindrical, including multiple peaks and troughs, connected by straight rods, giving the metal corrugated coil 111 good radial and axial extensibility. The number of metal corrugated coils 111 can be one or more, preferably two or more, and they are made of materials with good biocompatibility and elasticity, such as nickel-titanium alloy and stainless steel. The connection between the support body 11 and the membrane 12 can be achieved by high-temperature pressure treatment or by suture fixation. If suture fixation is used, it requires stitching with suture thread. The suture thread is made of a biocompatible material, such as PTFE, PET, or PP. In this embodiment, the metal corrugated coil 111 and the membrane 12 are stitched together with suture thread.

[0042] Further, the snap-fit ​​unit 13 of this embodiment includes a limiting member 132 and a connecting member 131. One end of the connecting member 131 is connected to the metal bellows 111, and the other end of the connecting member 131 is connected to the limiting member 132. In one embodiment, the minimum radial dimension of the limiting member 132 is greater than the maximum radial dimension of the connecting member 131. The connecting member 131 includes a strip-shaped structure, an arc-shaped structure, a spiral structure, a wave-shaped structure, or a zigzag structure, and the limiting member 132 includes a spherical structure, a disc-shaped structure, a polyhedral structure, or an irregular structure. In this embodiment, specifically, the connecting member 131 is a strip-shaped structure, and the limiting member 132 is a spherical structure, the diameter of which is greater than the width of the strip-shaped structure.

[0043] In another embodiment, the limiting member 132 includes a strip-shaped structure, an arc-shaped structure, a spiral structure, a wave-shaped structure, or a zigzag structure, and the connection point between the connecting member 131 and the limiting member 132 is at a position other than the two ends of the limiting member 132. For example, the limiting member 132 is a strip-shaped structure, and the connecting member 131 is a strip-shaped structure, and the two are connected in a similar "T" shape.

[0044] Both the connector 131 and the limiting member 132 can be made of metallic materials with good biocompatibility and elasticity, such as nickel-titanium alloy or 316L stainless steel, thereby ensuring that the connector 131 and the limiting member 132 have a certain strength. The connector 131 can have elastic deformation characteristics to provide better flexibility, or the connector 131 can be without elastic deformation characteristics.

[0045] In this embodiment, Figure 2 The middle metal wave ring 111 can be an inner wave ring that is set separately inside the outer wave ring of the coating support 10, in which case the coating support 10 is a double-layer wave ring design; or it can be any one of the multiple wave rings axially arranged on the coating support 10, in which case the coating support 10 is a single-layer wave ring design.

[0046] Combination Figure 3 and Figure 4 As shown, the conveyor 20 of this embodiment includes a first sheath core 21, which is a hollow structure with openings at both ends. At least one protrusion 211 is provided on the outer peripheral wall of the first sheath core 21. The protrusion 211 includes a first part 2111 and a second part 2112 connected to each other. The first part 2111 has a fixed end connected to the first sheath core 21, and the second part 2112 has a free end extending distally. Figure 4 In this configuration, the first portion 2111 is used to axially fix the snap-fit ​​unit 13, and the second portion 2112 is used to radially fix the snap-fit ​​unit 13. When the first sheath core 21 is pushed distally, the snap-fit ​​unit 13 disengages from the first portion 2111 and the second portion 2112, and the snap-fit ​​unit 13 is released from the protrusion 211. In other embodiments, the protrusion 211 may not include the second portion 2112, and the snap-fit ​​unit 13 only needs to be axially fixed, because the covered support 10 is compressed between the sheath (not shown) and the first sheath core 21, and radial fixation can be achieved by the compressive force of the sheath on the covered support 10.

[0047] Specifically, the first part 2111 has a first through hole (not shown in the figure), the second part 2112 has a second through hole 2113, the second through hole 2112 passes through the free end, the first through hole and the second through hole 2113 are interconnected, the snap-fit ​​unit 13 includes a limiting member 132 and a connecting member 131 connected to each other, the limiting member 132 can be snapped between the second part 2112 and the first sheath core 21, the connecting member 131 passes through the first through hole, when the first sheath core 21 is pushed to the distal end, the snap-fit ​​unit 13 can be released through the second through hole 2112.

[0048] Based on the above classification of the shape of the limiting member 132, there are two cases: The first case is when the limiting member 132 includes a spherical structure, a disc-shaped structure, a polyhedral structure, or an irregular structure, wherein the minimum radial dimension of the limiting member 132 is greater than the maximum radial dimension of the connecting member 131, the minimum radial dimension of the limiting member 132 is greater than the maximum of the maximum width of the first through hole and the maximum width of the second through hole 2113, and the maximum radial dimension of the connecting member 131 is less than the minimum of the minimum width of the first through hole and the minimum width of the second through hole 2113, so that the limiting member 132 cannot pass through the first through hole and the second through hole 2113, while the connecting member 131 can pass through the first through hole and the second through hole 2113. Two through holes 2113; the second case is when the limiting member 132 includes a strip-shaped structure, an arc-shaped structure, a spiral structure, a wavy structure, or a broken line structure, and the connection point between the connecting member 131 and the limiting member 132 is any position of the limiting member 132 other than its two ends, wherein the length of the limiting member 132 is greater than the maximum of the maximum width of the first through hole and the maximum width of the second through hole 2113, and the maximum radial dimension of the connecting member 131 is less than the minimum of the minimum width of the first through hole and the minimum width of the second through hole 2113, so that the limiting member 132 cannot pass through the first through hole and the second through hole 2113, while the connecting member 131 can pass through the first through hole and the second through hole 2113. The length of the limiting member 132 refers to the distance between the two ends of the strip-shaped structure, arc-shaped structure, spiral structure, wavy structure, or broken line structure in its natural state.

[0049] In this embodiment, the protrusion 211 is generally L-shaped. In other embodiments, the protrusion 211 may be generally T-shaped, cross-shaped, or other shapes. To facilitate the transport process of the film-coated support 10, the protrusion 211 is positioned as close as possible to the distal end of the first sheath core 21. It may be at a position flush with the distal end face of the first sheath core 21, or at another position close to the distal end face.

[0050] In this embodiment, during operation, one end of the connector 131 connected to the limiting member 132 passes through the second through hole 2113 and the first through hole from the free end of the protrusion 211, and pulls the limiting member 132 to the position between the second part 2112 and the first sheath core 21 and locks it in place. In this manner, multiple limiting members 13 inside the film-coated bracket 10 are sequentially locked to the positions between the second part of the corresponding protrusion and the first sheath core 21, thereby fixing the film-coated bracket 10 onto the first sheath core 21.

[0051] The delivery device in this embodiment also includes a sheath (not shown in the figure). When the covered stent 10 needs to be delivered, the covered stent 10 is sleeved on the outside of the first sheath core 21, and the limiting member 132 of the locking unit 13 is locked between the second part 2112 of the protrusion 211 and the first sheath core 21. Then, the covered stent 10 together with the first sheath core 21 is assembled into the sheath. In actual use, the delivery device is first delivered to the lesion site, and the sheath is withdrawn proximally to complete the release of the covered stent 10. As the sheath is withdrawn proximally, a force is applied to the covered stent 10 towards the proximal end. The limiting member 132 is always subjected to force in the proximal direction, so that the limiting member 132 is always locked between the second part 2112 and the first sheath core 21. During the process of withdrawing the sheath to release the covered stent 10, the covered stent 10 is always fixed on the first sheath core 21. Then, the first sheath core 21 is withdrawn proximally, and the connector 131 and the limiting member 132 extend together from the free end of the protrusion 211, detaching the covered stent 10 and the first sheath core 21. Finally, the sheath of the delivery device and the first sheath core 21 are withdrawn from the body, leaving the covered stent 10 in the patient's body to isolate the lesion. During this operation, the clamping unit 13 remains inside the stent body 11 and does not come into contact with the blood vessel wall. After the covered stent 10 completes the delivery process, the connection between it and the delivery device is released, and the covered stent 10 is completely released from the delivery device. The clamping unit 13 will not cause damage to the blood vessel wall due to the outward force generated by the release, thereby ensuring the safety and reliability of the surgical procedure and preventing unnecessary damage to the patient.

[0052] Implementation Method 2

[0053] Combination Figure 5 and Figure 6As shown, the coated support 10 of this embodiment is basically the same as that in Embodiment 1. The coated support 10 of this embodiment includes a support body 11, a film 12, and at least one snap-fit ​​unit 13. The support body 11 includes at least one metal bellows 111. The film 12 covers the surface of the support body 11. At least one snap-fit ​​unit 13 is disposed inside the support body 11 covered with the film 12, and the snap-fit ​​unit 13 can snap onto the conveyor used to transport the coated support 10. Unlike Embodiment 1, in this embodiment, the snap-fit ​​unit 13 is connected to the film 12, that is, one end of the connector 131 is connected to the film 12, and the other end of the connector 131 is connected to the limiting member 132, thereby realizing the setting of the snap-fit ​​unit 13 inside the support body 11.

[0054] Implementation Method 3

[0055] Combination Figures 7 to 10 As shown, the conveyor 20 of this embodiment includes a first sheath core 21 and a second sheath core 22. The first sheath core 21 is sleeved on the outside of the second sheath core 22, and the first sheath core 21 is basically the same as that in Embodiment 1. In this embodiment, the outer peripheral wall of the second sheath core 22 is provided with at least one boss 221 corresponding to the free end position of the protrusion 211. The boss 221 can abut against the free end of the L-shaped protrusion 211, thereby closing the distal end of the second through hole 2113. It should be noted that in this embodiment, the free end of the protrusion 211 must extend at least beyond the distal end of the first sheath core 21 in order to cooperate with the boss 221 of the second sheath core 22.

[0056] Combination Figure 9 and Figure 10 As shown, when the first sheath core 21 is fitted outside the second sheath core 22, the distal end face of the protrusion 211 abuts against the surface of the boss 221, and a closed locking cavity 23 with openings on both sides is formed between the protrusion 211 and the boss 221. The limiting member 132 of the locking unit 13 is locked inside the closed locking cavity 23, and the connecting member 131 of the locking unit 13 extends to the outside of the closed locking cavity 23, thereby limiting and fixing the film-coated bracket 10 fitted on the first sheath core 21.

[0057] The conveyor 20 of this embodiment can be used to convey any of the film-coated brackets 10 described in Embodiment 1 and Embodiment 2. The snap-fit ​​unit 13 can snap onto the conveyor 20, thereby realizing the fixing and conveying process of the film-coated bracket 10. When conveying the film-coated bracket 10 using the conveyor 20 of this embodiment, the limiting member 132 is always within the closed locking cavity 23 formed by the protrusion 211 and the boss 221. The limiting member 132 will not be released prematurely, thereby ensuring the safety and reliability of the conveying process of the film-coated bracket 10.

[0058] The specific release process is basically the same as that in Implementation Method 1. The sheath is removed first, and then the first sheath core 21 is removed to achieve the release and release of the covered stent 10 in the body. It will not be described in detail here.

[0059] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A covered stent, characterized by, The application relates to a stent, which comprises: a stent body comprising at least one metal coil; a film arranged on the stent body; and at least one clamping unit arranged inside the stent body with the film, which can be clamped on a conveying device for conveying the film stent.

2. The stent graft of claim 1, wherein, The clamping unit comprises a limiting member and a connecting member, one end of the connecting member is connected with the metal coil or the film, and the other end of the connecting member is connected with the limiting member.

3. The stent graft of claim 2, wherein, The minimum radial dimension of the limiting member is greater than the maximum radial dimension of the connecting member, and the limiting member comprises a spherical structure, a disc structure, a polyhedral structure or an irregular structure.

4. The stent graft of claim 2, wherein, The limiting member comprises a strip structure, an arc structure, a spiral structure, a wave structure or a zigzag structure, and the connecting member is connected with the limiting member at a position other than the two ends of the limiting member.

5. The stent graft of claim 2, wherein, The connecting member comprises a strip structure, an arc structure, a spiral structure, a wave structure or a zigzag structure.

6. A delivery device for delivering the covered stent of claim 1, wherein, The conveying device comprises: a first sheath core, and at least one protrusion is arranged on the outer peripheral wall of the first sheath core, the protrusion comprises a first part, one end of the first part is connected with the first sheath core, the first part has a first through hole, the first through hole penetrates the other end of the first part, and the clamping unit penetrates into the first through hole from the other end of the first part to axially fix the clamping unit.

7. The conveyor of claim 6, wherein, The protrusion further comprises a second part, the second part and the first part are connected with each other, the second part has a free end, the second part has a second through hole, the second through hole penetrates the free end, the second through hole and the first through hole are communicated with each other, the clamping unit penetrates into the second through hole and the first through hole from the free end, and the second part radially fixes the clamping unit.

8. The conveyor of claim 7, wherein, The clamping unit comprises a limiting member and a connecting member which are connected with each other, the minimum radial dimension of the limiting member is greater than the maximum value of the maximum width of the first through hole and the maximum width of the second through hole, and the maximum radial dimension of the connecting member is less than the minimum value of the minimum width of the first through hole and the minimum width of the second through hole.

9. The conveyor of claim 7, wherein, When the limiting member comprises a strip structure, an arc structure, a spiral structure, a wave structure or a zigzag structure, and the connecting member is connected with the limiting member at a position other than the two ends of the limiting member, the length of the limiting member is greater than the maximum value of the maximum width of the first through hole and the maximum width of the second through hole, and the maximum radial dimension of the connecting member is less than the minimum value of the minimum width of the first through hole and the minimum width of the second through hole.

10. The conveyor of claim 7, wherein, The conveying device further comprises a second sheath core, the first sheath core is sleeved outside the second sheath core, the outer peripheral wall of the second sheath core is provided with at least one boss corresponding to the free end of the protrusion, and the free end of the protrusion can abut against the boss.

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