CN115054293A

CN115054293A - Conveying cable and preparation method thereof

Info

Publication number: CN115054293A
Application number: CN202210685002.3A
Authority: CN
Inventors: 王禹都; 陈贤淼
Original assignee: Lifetech Scientific Shenzhen Co Ltd
Current assignee: Lifetech Scientific Shenzhen Co Ltd
Priority date: 2017-12-29
Filing date: 2017-12-29
Publication date: 2022-09-16
Also published as: CN109984779A; CN109984779B

Abstract

The invention relates to a conveying cable which comprises a first section of nickel-titanium cable and a second section of nickel-titanium cable connected with the first section of nickel-titanium cable, wherein the length ratio of the first section of nickel-titanium cable to the second section of nickel-titanium cable is 1: 12.75-1: 1, and the equivalent bending rigidity of the first section of nickel-titanium cable is smaller than 1/2 of the equivalent bending rigidity of the second section of nickel-titanium cable. One end of the conveying cable is relatively soft, the flexibility is relatively good, and the overall bending rigidity of the conveying cable meets the pushing requirement.

Description

Conveying cable and preparation method thereof

Technical Field

The invention relates to the field of interventional medical instruments, in particular to a conveying cable and a preparation method thereof.

Background

With the continuous development of interventional medical devices, catheter-mediated minimally invasive therapy is becoming an important method for treating congenital heart diseases such as Atrial Septal Defect (ASD), Ventricular Septal Defect (VSD), Patent Ductus Arteriosus (PDA) and Patent Foramen Ovale (PFO).

The interventional medical device is delivered to a human lesion site by a delivery system through catheter interventional minimally invasive therapy. Taking a ventricular septal defect occlusion as an example, the delivery system 100 shown in fig. 1 is used to push a ventricular septal defect occluder 20 to a desired position by means of a delivery cable 10 during an interventional procedure. One end of the delivery cable 10 is connected to the ventricular septal defect occluder 20, and the other end is connected to the handle 30 of the delivery system 100, and the delivery cable 10 plays a key role in the pushing process of the ventricular septal defect occluder 20.

The existing conveying cable 10 is typically a stainless steel spring tube, such as 304 stainless steel tube, 316L stainless steel tube, etc. The conventional stainless steel spring tube 10 is formed by winding and shaping a plurality of stainless steel wires 12, and has a circular cross-section as shown in fig. 2. This stainless steel spring tube 10 has a high hardness and bending rigidity. Due to the complexity of the blood vessel path and the diseased area in the human body, a delivery system 100 is required to withstand large bends in the delivery process for a blood vessel with a large degree of bending or a portion that needs to be bent to reach, such as a ventricular septal defect. Thus, it is desirable that the sheath used in the delivery system 100 be capable of bending at the head at an angle to pass through a curved vessel or to align with a defect site, but this bending is particularly difficult due to the relatively high stiffness and bending stiffness characteristics of the existing delivery cables 10. Particularly with the delivery system 100 used in a transcatheter ventricular septal defect occlusion procedure, the procedure using the existing stainless steel spring tube 10 would be very challenging due to the greater degree of bending of the sheath head, making the transcatheter ventricular septal defect occlusion procedure difficult to perform. Therefore, the head of the conveying wire rope 10 needs to be softened.

The existing softening method for the stainless steel spring tube conveying steel cable 10 is a machining method. The outer surface of the end of the stainless steel spring tube 10 to which the interventional medical device is attached is uniformly ground in an axisymmetric manner to obtain a ground region having a relatively small outer diameter, and the cross section of the ground region is shown in fig. 3. Since the bending stiffness EI is determined jointly by the material properties E (modulus of elasticity) and the structural properties I (moment of inertia in cross section). As the stainless steel spring tube delivery wire rope is ground, its end section moment of inertia I becomes smaller, and correspondingly the bending stiffness becomes smaller. The stainless steel spring tube 10 after being processed has the characteristics that the front section is softer and is easy to deform, and the rear section is harder and can provide larger pushing force. The softening method is widely used for metal winding spring tubes at present, but the external force in the grinding process easily causes the woven structure to be scattered and separated due to machining, the machining process consumes labor hours, and the product performance is easily inconsistent and even poor due to machining errors. In addition, the softening effect achieved by the method is not ideal, and after grinding, the spring tube still has great elasticity and only has small bending rigidity. Particularly for the delivery system 100 used in transcatheter ventricular septal defect occlusion (as shown in figure 4), the head of the delivery system 100 is bent to a greater extent, and the head of the stainless steel spring tube 10 is required to be more flexible. The mechanical grinding processing mode is difficult to satisfy.

Disclosure of Invention

Based on this, it is necessary to provide a conveying cable with good flexibility at one end and with overall bending rigidity meeting the pushing requirement.

A conveying cable comprises a first section of nickel-titanium cable and a second section of nickel-titanium cable connected with the first section of nickel-titanium cable, the length ratio of the first section of nickel-titanium cable to the second section of nickel-titanium cable is 1: 12.75-1: 1, and the equivalent bending stiffness of the first section of nickel-titanium cable is smaller than 1/2 of the equivalent bending stiffness of the second section of nickel-titanium cable.

In one embodiment, the first and second lengths of nitinol cable are a unitary structure; or the first section of nickel titanium cable is fixedly connected with the second section of nickel titanium cable.

In one embodiment, the equivalent bending stiffness of the first section of the nickel titanium cable is 50-400N-mm ² The equivalent bending rigidity of the second section of nickel-titanium cable is 150-1000 N.mm ² 。

In one embodiment, the nickel in the first and second nitinol cables is present in an atomic percentage of 49.8 at% to 51.2 at%.

In one embodiment, the atomic percent of nickel in the first nickel titanium cable is 49.8-50.8 at%, and the atomic percent of nickel in the second nickel titanium cable is 0.2-0.4 at% higher than the atomic percent of nickel in the first nickel titanium cable.

In one embodiment, the length of the first section of nickel titanium cable is 80-200 mm, and the length of the second section of nickel titanium cable is 600-1020 mm; or the length of the first section of nickel-titanium cable is 80-200 mm, and the length of the second section of nickel-titanium cable is 200-520 mm.

In one embodiment, the first and second sections of nitinol cables are hollow nitinol tubes formed by helically winding a plurality of nitinol wires around a cylindrical mandrel; or the first section of nickel-titanium cable and the second section of nickel-titanium cable are both solid nickel-titanium cables formed by spirally winding a plurality of nickel-titanium wires; or the first section of nickel-titanium cable and the second section of nickel-titanium cable are both single nickel-titanium wires; or one of the first section of nickel-titanium cable and the second section of nickel-titanium cable is a hollow nickel-titanium tube formed by spirally winding a plurality of nickel-titanium wires around a cylindrical mandrel, and the other one of the first section of nickel-titanium cable and the second section of nickel-titanium cable is a solid nickel-titanium cable formed by winding a single nickel-titanium wire or a plurality of nickel-titanium wires; or one of the first section of nickel-titanium cable and the second section of nickel-titanium cable is a solid nickel-titanium cable formed by winding a plurality of nickel-titanium wires, and the other is a single nickel-titanium wire.

In one embodiment, the diameters of circumscribed circles of the hollow nickel-titanium pipe formed by spirally winding a plurality of nickel-titanium wires around a cylindrical mandrel and the solid nickel-titanium cable formed by spirally winding a plurality of nickel-titanium wires are both 1.0-4.5 mm; the diameter of each single nickel-titanium wire is 0.5-1.0 mm.

In one embodiment, the delivery cable further comprises a transition section nitinol cable, one end of the transition section nitinol cable is connected to the first section nitinol cable, and the other end of the transition section nitinol cable is connected to the second section nitinol cable.

A method of making a transfer cable comprising the steps of:

providing a nickel titanium cable; and

one end of the nickel-titanium cable is placed in an environment with the temperature of 450-540 ℃ for heat treatment for at least 30min, and then the nickel-titanium cable is cooled to 200 ℃ within 10-150 min, so that the nickel-titanium cable forms a first section of nickel-titanium cable and a second section of nickel-titanium cable connected with the first section of nickel-titanium cable, wherein the length ratio of the first section of nickel-titanium cable to the second section of nickel-titanium cable is 1: 12.75-1: 1, and the equivalent bending stiffness of the first section of nickel-titanium cable is smaller than 1/2 of the equivalent bending stiffness of the second section of nickel-titanium cable.

In one embodiment, the step of placing one end of the nickel-titanium cable in an environment with the temperature of 450-540 ℃ for heat treatment for at least 30min is to perform heat treatment in a vacuum environment or perform heat treatment in a protective gas atmosphere.

A method of making a transfer cable comprising the steps of:

providing a nickel titanium cable; and

and heating one end of the nickel-titanium cable to 450-540 ℃ by adopting laser, cooling to 200 ℃ in 10-150 min, and enabling the nickel-titanium cable to form a first section of nickel-titanium cable and a second section of nickel-titanium cable connected with the first section of nickel-titanium cable, wherein the length ratio of the first section of nickel-titanium cable to the second section of nickel-titanium cable is 1: 12.75-1: 1, and the equivalent bending rigidity of the first section of nickel-titanium cable is smaller than 1/2 of the equivalent bending rigidity of the second section of nickel-titanium cable.

A method of making a transfer cable comprising the steps of:

providing a first section of nickel-titanium cable and a second section of nickel-titanium cable, wherein the length ratio of the first section of nickel-titanium cable to the second section of nickel-titanium cable is 1: 12.75-1: 1;

placing the first section of nickel-titanium cable in an environment with the temperature of 450-540 ℃ for heat treatment for at least 30min, and then cooling to 200 ℃ within 10-150 min to form a softened first section of nickel-titanium cable; or heating the first section of nickel-titanium cable to 450-540 ℃ by adopting laser, and then cooling to 200 ℃ in 60-150 minutes to form a softened first section of nickel-titanium cable; and

connecting the second length of nitinol cable with the softened first length of nitinol cable to obtain the delivery cable, wherein the equivalent bending stiffness of the first length of nitinol cable is less than 1/2 of the equivalent bending stiffness of the second length of nitinol cable.

The conveying cable comprises a first section of nickel-titanium cable and a second section of nickel-titanium cable connected with the first section of nickel-titanium cable, the length ratio of the first section of nickel-titanium cable to the second section of nickel-titanium cable is set to be 1: 12.75-1: 1 reasonably, and the bending rigidity of the first section of nickel-titanium cable is smaller than 1/2 of the bending rigidity of the second section of nickel-titanium cable, so that one end of the conveying cable is softer and better in flexibility, and the overall bending rigidity of the conveying cable meets the pushing requirement.

Drawings

Figure 1 is a schematic view of a prior art delivery system in connection with a ventricular septal defect occluder;

FIG. 2 is a cross-sectional view of a prior art delivery system prior to grinding of the delivery cable;

FIG. 3 is a cross-sectional view of a prior art conveyor system after grinding of the conveyor cable;

FIG. 4 is a schematic illustration of a prior art transcatheter ventricular septal defect occlusion;

FIG. 5 is a schematic structural view of a transfer cable according to an embodiment of the present invention;

FIG. 6 is a schematic representation of the bending stiffness of the first and second sections of the nitinol cable of the delivery cable shown in FIG. 5;

FIG. 7 is a schematic structural view of another embodiment of a transfer cable;

FIG. 8 is a schematic representation of the bending stiffness of the first, transition and second sections of the nitinol cable of the delivery cable of FIG. 7.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, but rather should be construed as broadly as the present invention is capable of modification in various respects, all without departing from the spirit and scope of the present invention.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

Referring to fig. 5, one embodiment of a delivery cable 200 for delivering an interventional medical device, such as an occluder for treating congenital heart disease. The delivery cable 200 includes a first length of nitinol cable 210 and a second length of nitinol cable 220 connected to one end of the first length of nitinol cable 210.

The first section of nitinol cable 210 and the second section of nitinol cable 220 are both hollow nitinol tubes formed by a plurality of nitinol wires spirally wound around a cylindrical mandrel and shaped. The circumscribed circles of the first and second lengths of

nitinol cable

210 and 220 are of equal diameter. The first and second lengths of

nitinol cable

210 and 220 are integrally formed to form the delivery cable 200. It is understood that in other embodiments, the first and

second nitinol cables

210 and 220 are fixedly connected to form the delivery cable 200, such as by welding one end of the first nitinol cable 210 to one end of the second nitinol cable 220. The first section of the nitinol cable 210 and the second section of the nitinol cable 220 are connected by welding, so that the bending of the first section of the nitinol cable 210 at the heart is not affected, and the bending rigidity of the whole conveying cable 200 is not adversely affected, as long as the welding connection meets the strength requirement.

In another embodiment, the delivery cable 200 may be a solid nitinol cable formed by helically winding a plurality of nitinol wires. The diameter of the circumscribed circle of the conveying cable 200 is 1.0-4.5 mm no matter the conveying cable 200 is a hollow nickel-titanium tube or a solid nickel-titanium cable; preferably, the first and

second nitinol cables

210 and 220 are hollow nitinol tubes formed by winding 9 nitinol wires with a wire diameter of 0.36mm around a cylindrical mandrel with a diameter of 0.85 mm.

It is understood that in other embodiments, the first and second lengths of

nitinol cable

210 and 220 may each be a solid cable formed from a single nitinol wire, so long as the wire diameter of the single nitinol wire is sufficient. Preferably, the wire diameter of a single nickel-titanium wire is 0.5-1.0 mm.

Alternatively, in another embodiment, when the first and

second nitinol cables

210 and 220 are fixedly connected to form the delivery cable 200, one of the first and

second nitinol cables

210 and 220 is a hollow nitinol tube formed by a plurality of nitinol wires helically wound around a cylindrical mandrel, and the other is a single nitinol wire or a solid nitinol cable formed by a plurality of nitinol wires wound. Alternatively, one of the first and

second nitinol cables

210, 220 is a solid nitinol cable formed by winding a plurality of nitinol wires, and the other is a single nitinol wire.

It should be noted that in the embodiment where the first and

second nitinol cables

210 and 220 are fixedly connected to form the delivery cable 200, when the first and

second nitinol cables

210 and 220 are both solid structures, the cross-sections of the first and

second nitinol cables

210 and 220 are matched in size, for example, when the first and

second nitinol cables

210 and 220 are both single nitinol wires, the wire diameters of the first and

second nitinol cables

210 and 220 are equal. When one of the first section of nickel-titanium cable 210 and the second section of nickel-titanium cable 220 is a hollow nickel-titanium tube, and the other is a solid structure, the inner diameter of the hollow nickel-titanium tube is matched with the cross section of the solid structure, so that one end of the solid structure can penetrate through the hollow nickel-titanium tube.

It will be appreciated that whether delivery cable 200 is a hollow nitinol tube formed by helically winding a plurality of nitinol wires around a cylindrical mandrel, a solid nitinol cable formed by helically winding a plurality of nitinol wires, or a solid nitinol cable formed from a single nitinol wire, the nitinol wires may have a cross-section that is not limited, e.g., circular, oval, square, rectangular, etc.

The length ratio of the first section of nickel titanium cable 210 to the second section of nickel titanium cable 220 is 1: 12.75-1: 1. Referring to FIG. 6, the equivalent bending stiffness ((EI) of the first nitinol cable segment 210 _{Equivalence 2} ) Less than the equivalent bending stiffness ((EI) of the second length of nitinol cable 220) _{Equivalent 1} ) 1/2 of (1).

Bending stiffness refers to the ability of an object to resist its bending deformation. The ability of a material to resist bending deformation is expressed in terms of the product EI of the elastic modulus E of the material and the moment of inertia I of the cross section of the member being bent about its neutral axis. Because the actual bending rigidity can not be obtained by simply applying a formula due to the structure of the spring tube, the equivalent bending rigidity (EI) is measured by using a three-point bending method _{Equivalence of} ＝F/(48Yl ³ ) (ii) a Wherein F is the concentration force and Y is the deflectionAnd l is the span. Equivalent bending stiffness is an accurate and effective attribute for measuring the softness of the transfer cable 200.

During delivery of delivery cable 200 along the path of a blood vessel in vivo, there may be a tortuous path, particularly from the heart' S access (e.g., inferior vena cava) to the ventricular septal defect site, which may be shaped like an S. Therefore, the path of the sheath in the blood vessel of the human body is complicated and meandering, and the carrying cable 200 is subjected to a large resistance during the pushing. In order to be able to push the interventional medical device better to the defect site, on the one hand, the delivery cable 200 is required to have strong elasticity and rigidity; on the other hand, because the distal end of delivery cable 200 (the end distal to the handle, i.e., the end coupled to the interventional medical device) may be subject to significant bending, it is desirable that delivery cable 200 have a flexible head.

Therefore, the transmission cable 200 is required to be as flexible as possible to accommodate the change in the shape of the path, while satisfying its pushing performance and maintaining the torsion characteristics. By reasonably setting the ratio of the length L1 of the first section of nickel-titanium cable 210 to the length L2 of the second section of nickel-titanium cable 220 to be 1: 12.75-1: 1 and setting the equivalent bending rigidity of the first section of nickel-titanium cable 221 to be less than the equivalent bending rigidity of the second section of nickel-titanium cable 220, one end of the conveying cable 200 is relatively soft and relatively good in flexibility, the conveying cable can adapt to paths of different shapes, the overall bending rigidity of the conveying cable 200 meets the pushing requirement, and the interventional medical instrument can be smoothly pushed to an expected position through the sheath tube.

Preferably, the equivalent bending rigidity of the first section of the nickel-titanium cable is 50-400N-mm ² The equivalent bending rigidity of the second section of the nickel-titanium cable is 150-1000 N.mm ² . The equivalent bending rigidity of the first section of the nickel-titanium cable is 50-400 N.mm ² The value in the range and the equivalent bending rigidity of the second section of nickel-titanium cable are 150-1000 N.mm ² The value of (a) should satisfy 1/2 that the equivalent bending stiffness of the first section of the nitinol cable is less than the equivalent bending stiffness of the second section of the nitinol cable.

Preferably, when the delivery cable 200 is used in a femoral vein implantation pathway ventricular septal defect occlusion procedure, the ratio of the lengths of the first section of nickel titanium cable 210 and the second section of nickel titanium cable 220 is 1: 12.75-1: 3. Further preferably, the length of the first section of nickel titanium cable 210 is 80-200 mm, and the length of the second section of nickel titanium cable 220 is 600-1020 mm, so that when the delivery cable 200 is applied to the femoral vein implantation path ventricular septal defect occlusion, the second section of nickel titanium cable 220 can smoothly push the first section of nickel titanium cable 210 to the heart, and the first section of nickel titanium cable 210 can run inside the heart to reach the defect position.

In further embodiments, preferably, when the delivery cable 200 is used in a jugular vein implantation pathway ventricular septal defect occlusion procedure, the ratio of the lengths of the first and second sections of

nickel titanium cable

210, 220 is from 1:6.5 to 1: 1. Further preferably, the length of the first section of nickel titanium cable 210 is 80-200 mm, and the length of the second section of nickel titanium cable 220 is 200-520 mm, so that when the delivery cable 200 is applied to a jugular vein implantation path ventricular septal defect occlusion, the second section of nickel titanium cable 220 can smoothly push the first section of nickel titanium cable 210 to a heart part, and the first section of nickel titanium cable 210 can run inside the heart to reach a defect position.

It will be appreciated that in clinical applications, the lengths of the first and

second nitinol cables

210, 220 may be chosen appropriately depending on the implantation path and the size of the patient.

In the embodiment where the length of the first nitinol cable 210 is 80-200 mm and the length of the second nitinol cable 220 is 600-1020 mm, it is preferable that the length of the second nitinol cable 220 is not 1020mm when the length of the first nitinol cable 210 is 80 mm.

In the embodiment where the length of the first nitinol cable 210 is 80-200 mm and the length of the second nitinol cable 220 is 200-520 mm, it is preferable that the length of the second nitinol cable 220 is not 520mm when the length of the first nitinol cable 210 is 80 mm.

The content distribution of nickel element in the first and

second nitinol cables

210 and 220 is uniform. Preferably, the atomic percent of nickel in the first and second sections of

nitinol cable

210, 220 is 49.8 at% to 51.2 at% each.

In other embodiments, the delivery cable 200 has a non-uniform distribution of nickel content, with the first nitinol cable 210 being in a nickel-poor phase and the second nitinol cable 220 being in a nickel-rich phase, i.e., the atomic percent of nickel in the first nitinol cable 210 is less than the atomic percent of nickel in the second nitinol cable 220. Preferably, the atomic percent of nickel in the first nitinol cable 210 is 49.8-50.8 at%, and the atomic percent of nickel in the second nitinol cable 220 is 0.2-0.4 at% higher than the atomic percent of nickel in the first nitinol cable. Generally, the higher the nickel content, the more rigid the resulting nickel titanium cable after heat treatment. By setting the first section of the nickel-titanium cable 210 to be in the nickel-poor phase and the second section of the nickel-titanium cable 220 to be in the nickel-rich phase, the bending rigidity of the first section of the nickel-titanium cable 210 and the second section of the nickel-titanium cable 220 can be adjusted, so that the bending rigidity of the first section of the nickel-titanium cable 210 is smaller than that of the second section of the nickel-titanium cable 220.

It should be noted that the atomic percentages of nickel and titanium in the first and

second nitinol cables

210 and 220 are dominant, but it is not excluded that the first and

second nitinol cables

210 and 220 may contain other trace elements. In NiTi shape memory alloys, Ni functions similarly to Co, Cr, etc., and thus, in other embodiments, the stiffness of the transfer cable 200 may be adjusted by increasing the content of alloying elements such as Co, Cr, etc., while keeping the atomic percentage of Ni in the transfer cable constant.

Taking the ventricular septal occluder as an example, when the delivery cable 200 is used for delivering the ventricular septal occluder, one end of the first section of the nickel-titanium cable 210 of the delivery cable 200, which is far away from the second section of the nickel-titanium cable 220, is detachably connected with the ventricular septal occluder, one end of the second section of the nickel-titanium cable 220, which is far away from the first section of the nickel-titanium cable 210, is fixedly connected with a handle of a delivery system, then enters the heart through a femoral vein implantation path or a jugular vein implantation path under the guidance of a delivery sheath, then the first section of the nickel-titanium cable 210 bends and enters a ventricular septal defect part, after the ventricular septal occluder is released, the connection between the ventricular septal occluder and the first section of the nickel-titanium cable 210 is released, the delivery cable 200, the delivery sheath and the like are withdrawn from the body, and the ventricular septal defect occlusion operation is completed.

It is understood that the end of the first length of nitinol cable 210 distal to the second length of nitinol cable 220 may be removably attached to the interventional medical device to be delivered by a threaded connection or the like. For example, an internally threaded locking sleeve may be provided at an end of the first length of nitinol cable 210 distal to the second length of nitinol cable 220 for threaded connection to an interventional medical device, or a plurality of connecting wires may be provided at an end of the first length of nitinol cable 210 distal to the second length of nitinol cable 220 for detachable connection to an interventional medical device.

Taking ventricular septal defect occlusion as an example, when a traditional steel conveying cable, namely a stainless steel spring tube, is adopted to convey an occluder, the elasticity of the stainless steel spring tube is larger because the elasticity modulus of the stainless steel material is larger, about 200 GPa. Referring to fig. 4 again, after the ventricular septal occluder is delivered to the defect site of the heart 300 and released, the delivery cable 10 (stainless steel spring tube) is disconnected from the ventricular septal occluder 20, and due to the elasticity of the stainless steel spring tube, the stainless steel spring tube may be bounced to other sites of the heart 300, which may cause damage to other sites, or the stainless steel spring tube may be bounced to the ventricular septal occluder 20, which may cause damage to the ventricular septal occluder 20, for example, the flow-resistant membrane of the ventricular septal occluder 20 is scraped, thereby affecting the occlusion effect.

The elastic modulus of the nickel-titanium alloy is small, the maximum elastic modulus in different crystal phases is only 70-80 GPa and is less than half of the elastic modulus of stainless steel, after heat treatment, the minimum elastic modulus can be only 30GPa, and compared with a stainless steel cable, the elastic modulus of the nickel-titanium alloy cable is greatly reduced. Therefore, after the delivery cable 200 is disconnected from the heart ventricular septum occluder, the elastic action of the first section of the nickel-titanium cable 210 is beneficial to avoiding other parts of the heart or the heart ventricular septum occluder from being damaged, thereby being beneficial to improving the smoothness of the operation and reducing the clinical use risk.

Referring to fig. 7, another embodiment delivery cable 300 includes a first section of nitinol cable 310, a second section of nitinol cable 320, and a transition section of nitinol cable 330. The transition section nickel titanium cable 330 is arranged between the first section nickel titanium cable 310 and the second section nickel titanium cable 320, one end of the transition section nickel titanium cable 330 is connected with one end of the first section nickel titanium cable 310, and the other end is connected with one end of the second section nickel titanium cable 320. The first section of nitinol cable 310, the second section of nitinol cable 320, and the transition section of nitinol cable 330 are a unitary structure.

The first length of nitinol cable 310 is L1, the second length of nitinol cable 320 is L2, and the transition length of nitinol cable 330 is L3. The ratio of L1 to L2 is 1: 12.75-1: 1, and L3 is 10-100 mm.

Referring to FIG. 8, the second nitinol cable 320 has a constant equivalent bending stiffness of (EI) _{Equivalent 1} (ii) a Equivalent bending stiffness ((EI) of first segment of nickel-titanium cable 310) _{Equivalence 2} ) Constant (EI) _{Equivalence 2} Less than 1/2 (EI) _{Equivalent 1} . The equivalent bending stiffness of the transition section nitinol cable 330 gradually increases from a value equal to the equivalent bending stiffness of the first section nitinol cable 310 to (EI) _{Equivalent 1} I.e. from (EI) _{Equivalence 2} Gradually rise to (EI) _{Equivalent 1} 。

L1 is satisfied by properly setting the length L1 of the first length of nitinol cable 310 and the length L2 of the second length of nitinol cable 220: l2 is 1: 12.75-1: 1, the equivalent bending stiffness of the first nickel titanium cable section 310 is less than 1/2 of the equivalent bending stiffness of the second nickel titanium cable section 320, the equivalent bending stiffness of the transition section nickel titanium cable 330 is gradually increased from a value equal to the equivalent bending stiffness of the first nickel titanium cable section 310 to a value equal to the bending stiffness of the second nickel titanium cable section 320, so that one end of the conveying cable 300 is relatively flexible and relatively good in flexibility, the conveying cable can adapt to paths of different shapes, and the overall bending stiffness of the conveying cable 300 meets the pushing requirement.

A method of making a transfer cable of an embodiment, comprising the steps of:

s110: a nickel titanium cable is provided.

The nickel-titanium cable is a hollow nickel-titanium tube formed by spirally winding a plurality of nickel-titanium wires around a cylindrical mandrel, or a solid cable formed by spirally winding a plurality of nickel-titanium wires, or a single nickel-titanium wire. The nitinol cable has superelastic properties.

S120: one end of the nickel-titanium cable is placed in an environment with the temperature of 450-540 ℃ for heat treatment for at least 30min, and then the nickel-titanium cable is cooled to 200 ℃ within 10-150 min, so that the nickel-titanium cable forms a first section of nickel-titanium cable and a second section of nickel-titanium cable connected with the first section of nickel-titanium cable, wherein the length ratio of the first section of nickel-titanium cable to the second section of nickel-titanium cable is 1: 12.75-1: 1, and the equivalent bending rigidity of the first section of nickel-titanium cable is smaller than 1/2 of the equivalent bending rigidity of the second section of nickel-titanium cable.

One end of the nickel titanium cable is placed in the heat treatment furnace, and the other end of the nickel titanium cable is positioned outside the heat treatment furnace. The temperature of the heat treatment furnace is 450-540 ℃. And carrying out heat treatment on one end of the heat treatment furnace at 450-540 ℃ for at least 30min, and not carrying out heat treatment on the other end of the heat treatment furnace. Or cooling the region close to the heat treatment furnace at the other end outside the heat treatment furnace to lower the temperature of the one end outside the heat treatment furnace to less than 200 ℃, such as soaking in cold water or pouring with cold water, to reduce the high temperature generated by heat conduction, to keep the temperature of the region close to the heat treatment furnace consistent with that of the region far from the heat treatment furnace or to avoid the influence of heat conduction on the other end outside the heat treatment furnace.

And after the heat treatment is finished, cooling the end subjected to the heat treatment to 200 ℃ within 10-150 min, and then naturally cooling the end to room temperature or cooling the conveying cable to room temperature by adopting air cooling, water cooling and other modes.

The length of the end located outside the heat treatment furnace was L1, and the length of the end located outside the heat treatment furnace was L2. In the heat treatment process, when the area, close to the heat treatment furnace, at the other end outside the heat treatment furnace is cooled at the same time, so that the temperature of the end outside the heat treatment furnace is lower than 200 ℃, the nickel titanium cable forms a first section of nickel titanium cable with different equivalent bending stiffness and a second section of nickel titanium cable connected with the first section of nickel titanium cable. The length of the first section of nickel-titanium cable is L1, the length of the second section of nickel-titanium cable is L2, the ratio of L1 to L2 is 1: 12.75-1: 1, and the equivalent bending rigidity of the first section of nickel-titanium cable is smaller than 1/2 of the equivalent bending rigidity of the second section of nickel-titanium cable.

Preferably, the heat treatment is carried out in an environment of 450-540 ℃ for 30-120 min, and further preferably cooled to 200 ℃ within 60-150 min.

In the heat treatment process, when no cooling measure is taken for one end positioned outside the heat treatment furnace, after the heat treatment is finished and cooled, the nickel-titanium cable forms a first section of nickel-titanium cable, a second section of nickel-titanium cable and a transition section of nickel-titanium cable, and the two ends of the transition section of nickel-titanium cable are respectively connected with the first section of nickel-titanium cable and the second section of nickel-titanium cable. The length of the first section of nickel-titanium cable is L1, the length of the second section of nickel-titanium cable is L2, the length of the transition section of nickel-titanium cable is L3, L1: l2 is 1: 12.75-1: 1. The value of L3 is preferably 10 to 100 mm.

Preferably, the step of placing a section of the nickel-titanium cable in an environment of 450-540 ℃ for heat treatment for at least 30min is to perform heat treatment in a vacuum environment or in a protective gas atmosphere so as to prevent the nickel-titanium cable from being oxidized. The protective gas is a gas which does not react with the components in the nickel-titanium alloy, such as nitrogen, argon, helium and the like.

The heat treatment furnace may be a tube furnace. Alternatively, the heat treatment furnace may be another heat treatment apparatus capable of providing a vacuum environment at a temperature of 450 to 540 ℃ or a protective atmosphere environment at a temperature of 450 to 540 ℃.

According to the preparation method of the conveying cable, the area with a certain length at the end part of the nickel-titanium cable is subjected to heat treatment at 450-540 ℃, and then the area is cooled to 200 ℃ in 10-150 minutes, so that the equivalent bending rigidity of the section of the nickel-titanium cable subjected to heat treatment is small, a first section of the nickel-titanium cable with different equivalent bending rigidities and a second section of the nickel-titanium cable connected with the first section of the nickel-titanium cable are formed, and the conveying cable which can ensure that the equivalent bending rigidity of one end is small, the flexibility is strong, and the whole conveying cable has enough bending rigidity is prepared.

According to the preparation method of the conveying cable, the first section of the nickel-titanium cable is softened in a heat treatment mode, so that one end of the conveying cable is good in flexibility, and the bending rigidity of the whole conveying cable meets the pushing requirement. The preparation method does not need mechanical grinding, not only has high preparation efficiency, but also has higher reliability, can not generate the phenomenon that the braided structure is scattered and separated, and can avoid the problems of inconsistent product performance and even poor performance caused by mechanical processing errors.

A method of making a transfer cable according to another embodiment includes the steps of:

s210: a nickel titanium cable is provided.

The nickel-titanium cable is a hollow nickel-titanium tube formed by spirally winding a plurality of nickel-titanium wires around a cylindrical mandrel or a solid nickel-titanium cable formed by spirally winding a plurality of nickel-titanium wires or a single nickel-titanium wire. The nitinol cable has superelastic properties.

S220: one end of the nickel-titanium cable is heated to 450-540 ℃ by laser, and then cooled to 200 ℃ within 10-150 min, so that the nickel-titanium cable forms a first section of nickel-titanium cable and a second section of nickel-titanium cable connected with the first section of nickel-titanium cable, wherein the length ratio of the first section of nickel-titanium cable to the second section of nickel-titanium cable is 1: 12.75-1: 1, and the equivalent bending rigidity of the first section of nickel-titanium cable is 1/2 smaller than that of the second section of nickel-titanium cable.

Laser heating has the characteristic of local heating, and the metal is heated by adopting laser, so that the advantage of heating only a target area can be realized.

And heating a partial area of the nickel-titanium cable extending from the end part to the other end to 450-540 ℃ by using laser, cooling to 200 ℃ in 10-150 minutes, and finally naturally cooling to room temperature or cooling the conveying cable to room temperature by using air cooling, water cooling and other modes. One section heated by the laser forms a first section of the nickel-titanium cable, and the other section is a second section of the nickel-titanium cable connected with the first section of the nickel-titanium cable. The length ratio of the first section of nickel-titanium cable to the second section of nickel-titanium cable is 1: 12.75-1: 1, and the equivalent bending stiffness of the first section of nickel-titanium cable is smaller than 1/2 of the equivalent bending stiffness of the second section of nickel-titanium cable.

According to the preparation method of the conveying cable, the first section of the nickel-titanium cable is softened in a laser heat treatment mode, the length ratio of the first section of the nickel-titanium cable to the second section of the nickel-titanium cable is 1: 12.75-1: 1, the bending rigidity of the first section of the nickel-titanium cable is smaller than 1/2 of the bending rigidity of the second section of the nickel-titanium cable, one section of the conveying cable can be good in flexibility, and the bending rigidity of the whole conveying cable meets the pushing requirement. The preparation method does not need mechanical grinding, has high preparation efficiency and high reliability, does not generate the phenomenon that the braided structure is scattered and separated, and can avoid the problems of inconsistent product performance and even poor performance caused by machining errors.

The method utilizes the characteristic that laser heating can be carried out aiming at a local specific area, and only the first section of the nickel-titanium cable can be heated so as to accurately control 1/2 that the equivalent bending rigidity of the first section of the nickel-titanium cable is less than that of the second section of the nickel-titanium cable. And the laser heating time is very short, and the preparation efficiency can be obviously improved by adopting the laser heating.

A method of making a transfer cable according to yet another embodiment includes the steps of:

s310: providing a first section of nickel-titanium cable and a second section of nickel-titanium cable, wherein the length ratio of the first section of nickel-titanium cable to the second section of nickel-titanium cable is 1: 12.75-1: 1.

The first section of nickel-titanium cable and the second section of nickel-titanium cable are both hollow nickel-titanium tubes formed by spirally winding a plurality of nickel-titanium wires around a cylindrical mandrel or solid nickel-titanium cables formed by spirally winding a plurality of nickel-titanium wires. Or the first section of nickel-titanium cable and the second section of nickel-titanium cable are both single nickel-titanium wires. Or one of the first section of nickel-titanium cable and the second section of nickel-titanium cable is a hollow nickel-titanium tube formed by spirally winding a plurality of nickel-titanium wires around a cylindrical mandrel, and the other one of the first section of nickel-titanium cable and the second section of nickel-titanium cable is a solid nickel-titanium cable formed by winding a single nickel-titanium wire or a plurality of nickel-titanium wires. Or one of the first section of nickel-titanium cable and the second section of nickel-titanium cable is a solid nickel-titanium cable formed by winding a plurality of nickel-titanium wires, and the other is a single nickel-titanium wire.

S320: and (3) placing the first section of nickel-titanium cable in an environment with the temperature of 450-540 ℃ for heat treatment for at least 30min, and then cooling to 200 ℃ within 10-150 min to form a softened first section of nickel-titanium cable. Or heating the first section of nickel-titanium cable to 450-540 ℃ by adopting laser, and then cooling to 200 ℃ in 60-150 min to form a softened first section of nickel-titanium cable.

Preferably, the step of placing the first nickel titanium cable in an environment of 450-540 ℃ for heat treatment for at least 30min is to perform heat treatment in a vacuum environment or in a protective gas atmosphere to prevent the first nickel titanium cable from being oxidized. The protective gas is a gas which does not react with the components in the nickel-titanium alloy, such as nitrogen, argon, helium and the like.

And performing heat treatment, cooling to 200 ℃ for a specified time, and naturally cooling to room temperature or cooling the conveying cable to room temperature by adopting an air cooling mode, a water cooling mode and the like.

Preferably, the first section of the nickel-titanium cable is placed in an environment with the temperature of 450-540 ℃ for heat treatment for 30-120 min, and is further preferably cooled to 200 ℃ within 60-150 min.

S330: and connecting the second section of the nickel-titanium cable with the softened first section of the nickel-titanium cable to obtain the conveying cable, wherein the equivalent bending rigidity of the first section of the nickel-titanium cable is less than 1/2 of the equivalent bending rigidity of the second section of the nickel-titanium cable.

Preferably, the second section of the nickel titanium cable is fixedly connected with the softened first section of the nickel titanium cable so as to ensure the stability of pushing the interventional medical instrument by using the conveying cable. For example, the second section of the nickel titanium cable is fixedly connected with the softened first section of the nickel titanium cable by welding. Further preferably, in order to ensure that the first nickel titanium cable and the second nickel titanium cable are reliably connected by welding, the first nickel titanium cable and the second nickel titanium cable can be connected by sleeving the connecting sleeve on the first nickel titanium cable and the second nickel titanium cable at the same time and welding.

According to the preparation method of the conveying cable, the first section of the nickel-titanium cable is softened in a heat treatment mode, then the second section of the nickel-titanium cable is connected with the softened first section of the nickel-titanium cable, so that one section of the conveying cable is good in flexibility, and the bending rigidity of the whole conveying cable meets the pushing requirement. The preparation method does not need mechanical grinding, has high preparation efficiency and high reliability, does not generate the phenomenon that the braided structure is scattered and separated, and can avoid the problems of inconsistent product performance and even poor performance caused by machining errors.

In addition, the preparation method can accurately control the equivalent bending rigidity of the first section of the nickel-titanium cable and the second section of the nickel-titanium cable, so that the prepared conveying cable is good in consistency.

The above-described transport cable and its method of manufacture are further illustrated by the following specific examples.

The following test methods and equipment were used in the following examples:

1. measurement of flexural rigidity of conveying cable: the equivalent resistance is measured by a universal force measuring machine and a three-point bending methodFlexural rigidity (EI) _{Equivalence of} ＝F/(48Yl ³ ) Wherein F is the concentration force, Y is the deflection, and l is the span.

2. Laser heating was performed with a TruDisk type 10002 YAG laser.

Example 1

A hollow nickel titanium cable of 1100mm length was provided, formed by 9 nickel titanium wires of 0.36mm wire diameter wound around a cylindrical mandrel of 0.85mm diameter. The diameter of the circumscribed circle of the nickel-titanium cable is 1.57mm, and the atomic percentage of nickel in the nickel-titanium cable is 50.2 at%.

Preheating the heat treatment furnace to 500 ℃, then placing one end of the nickel titanium cable in the heat treatment furnace with the temperature of 500 ℃, and remaining the other end of the nickel titanium cable outside the heat treatment furnace. In the heat treatment process, one end of the furnace outside the heat treatment furnace is soaked by cold water to make the temperature lower than 200 ℃. Wherein, the length of one end in the heat treatment furnace is 80mm, and the length of one end outside the heat treatment furnace is 1020 mm. And the heat treatment furnace is in a vacuum environment, one end in the heat treatment furnace is subjected to heat treatment at 500 ℃ for 60min, then is cooled to 200 ℃ within 60min, and finally is naturally cooled to room temperature, so that the nickel-titanium cable forms a first section of nickel-titanium cable and a second section of nickel-titanium cable connected with the first section of nickel-titanium cable, and the conveying cable is obtained.

In the conveying cable, the length of the first section of nickel titanium cable is 80mm, and the length of the second section of nickel titanium cable is 1020 mm. The equivalent bending rigidity of the first section of the nickel-titanium cable is 120 +/-6 N.mm ² The equivalent bending rigidity of the second section of the nickel-titanium cable is 280 +/-14 N.mm ² 。

After the puncture system is adopted to puncture the cardiac ventricular septal defect of a healthy pig, the conveying cable is used in a conveying system, the ventricular septal defect occluder is conveyed to the cardiac ventricular septal defect part of the pig, and the conveying and releasing processes are smooth.

Example 2

A680 mm long hollow nitinol cable was provided formed by 8 nitinol wires with a wire diameter of 0.328mm wound around a cylindrical mandrel with a diameter of 0.705 mm. The diameter of the circumscribed circle of the nickel titanium cable is 1.361mm, and the atomic percentage of nickel in the nickel titanium cable is 49.8 at%.

Preheating the heat treatment furnace to 450 ℃, then placing one end of the nickel titanium cable in the heat treatment furnace with the temperature of 450 ℃, and remaining the other end of the nickel titanium cable outside the heat treatment furnace. In the heat treatment process, one end of the furnace outside the heat treatment furnace is soaked by cold water to make the temperature lower than 200 ℃. Wherein, the length of one end in the heat treatment furnace is 80mm, and the length of one end outside the heat treatment furnace is 600 mm. And the heat treatment furnace is in a vacuum environment, one end in the heat treatment furnace is subjected to heat treatment at 450 ℃ for 60min, then is cooled to 200 ℃ within 60min, and finally is naturally cooled to room temperature, so that the nickel-titanium cable forms a first section of nickel-titanium cable and a second section of nickel-titanium cable connected with the first section of nickel-titanium cable, and the conveying cable is obtained.

In the conveying cable, the length of the first section of nickel titanium cable is 80mm, and the length of the second section of nickel titanium cable is 600 mm. The equivalent bending rigidity of the first section of the nickel-titanium cable is 100 +/-5 N.mm ² The equivalent bending rigidity of the second section of the nickel-titanium cable is 240 +/-12 N.mm ² 。

After the heart ventricular septal defect of a healthy pig is punctured by the puncture system, the conveying cable is used in the conveying system, the ventricular septal defect occluder is conveyed to the heart ventricular septal defect part of the pig, and the conveying and releasing processes are smooth.

Example 3

A nickel titanium cable formed from a nickel titanium wire having a wire diameter of 0.8mm is provided. The length of the nickel titanium cable is 1200mm, and the atomic percentage of nickel in the nickel titanium cable is 51.2 at%.

Preheating the heat treatment furnace to 540 ℃, then placing one end of the nickel titanium cable in the heat treatment furnace with the temperature of 540 ℃, and remaining the other end of the nickel titanium cable outside the heat treatment furnace. In the heat treatment process, one end of the furnace outside the heat treatment furnace is soaked by cold water to make the temperature lower than 200 ℃. Wherein, the length of one end in the heat treatment furnace is 200mm, the heat treatment furnace is in a vacuum environment, one section in the heat treatment furnace is subjected to heat treatment at 540 ℃ for 60min, then is cooled to 200 ℃ within 60min, and finally is naturally cooled to room temperature. And after the heat treatment and the cooling to 200 ℃, continuously cooling to room temperature to enable the nickel-titanium cable to form a first section of nickel-titanium cable and a second section of nickel-titanium cable connected with the first section of nickel-titanium cable, thus obtaining the conveying cable.

In the conveying cable, the length of the first section of nickel titanium cable is 200mm, and the length of the second section of nickel titanium cable is 1000 mm. The equivalent bending rigidity of the first section of the nickel-titanium cable is 300 +/-15 N.mm ² The equivalent bending rigidity of the second section of the nickel-titanium cable is 900 +/-45 N.mm ² 。

Example 4

A hollow 800mm long nitinol cable is provided, formed by 9 nitinol wires of 0.36mm diameter and cold worked, wound around a cylindrical mandrel of 0.85mm diameter. The diameter of the circumscribed circle of the nickel-titanium cable is 1.57mm, and the atomic percentage of nickel in the nickel-titanium cable is 50 at%.

Preheating a heat treatment furnace to 500 ℃, then placing one end of the nickel-titanium cable in the heat treatment furnace with the temperature of 500 ℃, and remaining the other end of the nickel-titanium cable outside the heat treatment furnace. Wherein one end in the heat treatment furnace is 120mm, the heat treatment furnace is in a vacuum environment, one end in the heat treatment furnace is subjected to heat treatment at 500 ℃ for 60min, then is cooled to 200 ℃ within 120min, and finally is naturally cooled to room temperature. The other section located outside the heat treatment furnace was not subjected to any treatment. The nickel titanium cable forms first section nickel titanium cable, second section nickel titanium cable and changeover portion connecting cable, and first section nickel titanium cable and second section nickel titanium cable are connected respectively to the both ends of changeover portion connecting cable, obtain the conveying cable.

In the conveying cable, the length of the first section of nickel titanium cable is 120mm, the length of the second section of nickel titanium cable is 600mm, and the length of the transition section of nickel titanium cable is 80 mm. The equivalent bending rigidity of the first section of the nickel-titanium cable is 120 +/-6 N.mm ² The equivalent bending rigidity of the second section of the nickel-titanium cable is 280 +/-14 N.mm ² . The equivalent bending rigidity of the nickel-titanium cable at the transition section is 120 +/-6 N.mm ² Gradually increasing to 280 +/-14 N.mm ² 。

Example 5

The method comprises the steps of providing a first solid nickel-titanium cable and a second solid nickel-titanium cable which are formed by winding 4 nickel-titanium wires with the wire diameter of 0.56mm, wherein the length of the first nickel-titanium cable is 80mm, the length of the second nickel-titanium cable is 520mm, the diameter of a circumscribed circle of the first nickel-titanium cable and the second nickel-titanium cable is 1.57mm, the atomic percentage content of nickel in the first nickel-titanium cable is 49.8 at%, and the atomic percentage content of nickel in the second nickel-titanium cable is 50.2%.

Preheating a heat treatment furnace to 500 ℃, then placing the first section of nickel-titanium cable in the heat treatment furnace with the temperature of 500 ℃ and vacuum for heat treatment for 120min, then cooling to 200 ℃ within 120min, and finally naturally cooling to room temperature to obtain the softened first section of nickel-titanium cable.

And fixedly connecting the softened first section of nickel-titanium cable with the second section of nickel-titanium cable by welding to obtain the conveying cable.

In the conveying cable, the length of the first section of nickel titanium cable is 80mm, and the length of the second section of nickel titanium cable is 520 mm. The equivalent bending rigidity of the first section of the nickel-titanium cable is 300 +/-15 N.mm ² The equivalent bending rigidity of the second section of the nickel-titanium cable is 700 +/-35 N.mm ² 。

Example 6

The method comprises the steps of providing a first section of nickel-titanium cable and a second section of nickel-titanium cable, wherein the first section of nickel-titanium cable and the second section of nickel-titanium cable are both nickel-titanium wires with the wire diameter of 0.8 mm. Wherein, the length of the first section of nickel titanium cable is 100mm, the length of the second section of nickel titanium cable is 500mm, and the atomic percentage content of nickel in the first section of nickel titanium cable and the second section of nickel titanium cable is 49.8 at%.

Preheating a heat treatment furnace to 500 ℃, then placing the first section of nickel-titanium cable in the heat treatment furnace with the temperature of 500 ℃ and vacuum for heat treatment for 60min, then cooling to 200 ℃ in 60min, and finally naturally cooling to room temperature to obtain the softened first section of nickel-titanium cable.

In the conveying cable, the length of the first section of nickel titanium cable is 100mm, and the length of the second section of nickel titanium cable is 500 mm. The equivalent bending rigidity of the first section of the nickel-titanium cable is 100 +/-5 N.mm ² The equivalent bending rigidity of the second section of the nickel-titanium cable is 240 +/-12 N.mm ² 。

Example 7

A nickel titanium cable formed from a single nickel titanium wire is provided. The wire diameter of the nickel titanium cable is 1.0mm, and the length of the nickel titanium cable is 450 mm. The nickel-titanium cable has a nickel atom percentage of 51 at%.

Locally heating one end of the nickel-titanium cable to 500 ℃ by adopting laser, then cooling to 200 ℃ within 120min, and finally naturally cooling to room temperature. The length of the heated end was 120mm, and the other end was not subjected to any treatment.

After the laser heating treatment, the nickel-titanium cable forms a conveying cable comprising a first section of nickel-titanium cable and a second section of nickel-titanium cable, wherein the length of the first section of nickel-titanium cable is 120mm, and the length of the second section of nickel-titanium cable is 330 mm. The equivalent bending rigidity of the first section of the nickel-titanium cable is 350 +/-17.5 N.mm ² The equivalent bending rigidity of the second section of the nickel-titanium cable is 950 +/-47.5 N.mm ² 。

After the heart ventricular septal defect of the healthy pig is punctured by the puncture system, the conveying cable is used in the conveying system, and the ventricular septal defect occluder is conveyed to the heart ventricular septal defect part of the pig, so that the conveying process is smooth.

Example 8

A hollow nitinol cable of 850mm length was provided, formed by 9 nitinol wires of 0.36mm wire diameter, cold worked, wound around a cylindrical mandrel of 0.85mm diameter. The diameter of the circumscribed circle of the nickel-titanium cable is 1.57mm, and the atomic percentage of nickel in the nickel-titanium cable is 50.2 at%.

Locally heating one end of the nickel-titanium cable to 500 ℃ by adopting laser, then cooling to 200 ℃ within 60min, and finally naturally cooling to room temperature. The length of the heated end was 150mm, and the other end was not subjected to any treatment.

After the laser heating treatment, the nickel-titanium cable forms a conveying cable comprising a first section of nickel-titanium cable and a second section of nickel-titanium cable, wherein the length of the first section of nickel-titanium cable is 150mm, and the length of the second section of nickel-titanium cable is 700 mm. The equivalent bending rigidity of the first section of the nickel-titanium cable is 120 +/-6 N.mm ² The equivalent bending rigidity of the second section of the nickel-titanium cable is 280 +/-14 N.mm ² 。

Example 9

The nickel-titanium composite cable is characterized in that a first nickel-titanium cable section and a second nickel-titanium cable section are provided, wherein the first nickel-titanium cable section and the second nickel-titanium cable section are formed by 8 nickel-titanium wires with the wire diameter of 0.328mm wound around a cylindrical mandrel with the diameter of 0.705mm, the first nickel-titanium cable section is 100mm long, the second nickel-titanium cable section is 200mm long, the diameter of a circumscribed circle of the first nickel-titanium cable section and the second nickel-titanium cable section is 1.361mm, the atomic percentage content of nickel in the first nickel-titanium cable section is 49.8 at%, and the atomic percentage content of nickel in the second nickel-titanium cable section is 50.2%.

Preheating a heat treatment furnace to 450 ℃, then placing the first section of nickel-titanium cable in the heat treatment furnace with the temperature of 450 ℃ and vacuum for heat treatment for 60min, then cooling to 200 ℃ in 60min, and finally naturally cooling to room temperature to obtain the softened first section of nickel-titanium cable.

In the conveying cable, the length of the first section of the nickel titanium cable is 100mm, and the length of the second section of the nickel titanium cable is 200 mm. The equivalent bending rigidity of the first section of the nickel-titanium cable is 100 +/-5 N.mm ² The equivalent bending rigidity of the second section of the nickel-titanium cable is 240 +/-14N·mm ² 。

Example 10

Preheating a heat treatment furnace to 500 ℃, then placing one end of the nickel-titanium cable in the heat treatment furnace with the temperature of 500 ℃, and remaining the other end of the nickel-titanium cable outside the heat treatment furnace. In the heat treatment process, one end of the furnace outside the heat treatment furnace is soaked by cold water to make the temperature lower than 200 ℃. Wherein, the length of one end in the heat treatment furnace is 80mm, and the length of one end outside the heat treatment furnace is 1020 mm. And the heat treatment furnace is in a vacuum environment, one end in the heat treatment furnace is subjected to heat treatment at 500 ℃ for 30min, then is cooled to 200 ℃ within 150min, and finally is naturally cooled to room temperature, so that the nickel-titanium cable forms a first section of nickel-titanium cable and a second section of nickel-titanium cable connected with the first section of nickel-titanium cable, and the conveying cable is obtained.

In the conveying cable, the length of the first section of nickel titanium cable is 80mm, and the length of the second section of nickel titanium cable is 1020 mm. The equivalent bending rigidity of the first section of the nickel-titanium cable is 120 plus or minus 20 N.mm ² The equivalent bending rigidity of the second section of the nickel-titanium cable is 280 plus or minus 20 N.mm ² 。

Example 11

Preheating the heat treatment furnace to 500 ℃, then placing one end of the nickel titanium cable in the heat treatment furnace with the temperature of 500 ℃, and remaining the other end of the nickel titanium cable outside the heat treatment furnace. In the heat treatment process, one end of the furnace outside the heat treatment furnace is soaked by cold water to make the temperature lower than 200 ℃. Wherein, the length of one end in the heat treatment furnace is 80mm, and the length of one end outside the heat treatment furnace is 1020 mm. And the heat treatment furnace is in a vacuum environment, one end in the heat treatment furnace is subjected to heat treatment at 500 ℃ for 600min, then is cooled to 200 ℃ within 10min, and finally is naturally cooled to room temperature, so that the nickel-titanium cable forms a first section of nickel-titanium cable and a second section of nickel-titanium cable connected with the first section of nickel-titanium cable, and the conveying cable is obtained.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. The conveying cable is characterized by comprising a first section of nickel-titanium cable and a second section of nickel-titanium cable connected with the first section of nickel-titanium cable, the length ratio of the first section of nickel-titanium cable to the second section of nickel-titanium cable is 1: 12.75-1: 1, and the equivalent bending stiffness of the first section of nickel-titanium cable is smaller than 1/2 of the equivalent bending stiffness of the second section of nickel-titanium cable.

2. The delivery cable of claim 1, wherein the first and second lengths of nitinol cable are a unitary structure; or the first section of nickel titanium cable is fixedly connected with the second section of nickel titanium cable.

3. The transfer cable of claim 1, wherein the first length of nitinol cable has an equivalent bending stiffness of 50-400N-mm ² The equivalent bending rigidity of the second section of nickel-titanium cable is 150-1000 N.mm ² 。

4. The delivery cable of claim 1, wherein the atomic percent of nickel in each of the first and second lengths of nitinol cable is between 49.8 at% and 51.2 at%.

5. The delivery cable of claim 1, wherein the atomic percent of nickel in the first section of nitinol cable is 49.8-50.8 at%, and the atomic percent of nickel in the second section of nitinol cable is 0.2-0.4 at% higher than the atomic percent of nickel in the first section of nitinol cable.

6. The transfer cable of claim 1, wherein the first length of nitinol cable is 80-200 mm in length and the second length of nitinol cable is 600-1020 mm in length; or the length of the first section of nickel-titanium cable is 80-200 mm, and the length of the second section of nickel-titanium cable is 200-520 mm.

7. The delivery cable of claim 1, wherein the first and second lengths of nitinol cable are each a single nitinol wire.

8. The transfer cable of claim 7, wherein the single wire of nickel titanium has a diameter of 0.5 to 1.0 mm.

9. The delivery cable of claim 1, further comprising a transition section of nitinol cable connected at one end to the first section of nitinol cable and at the other end to the second section of nitinol cable.

10. A preparation method of a conveying cable is characterized by comprising the following steps:

providing a nickel titanium cable; and

one end of the nickel-titanium cable is placed in an environment with the temperature of 450-540 ℃ for heat treatment for at least 30min, and then the nickel-titanium cable is cooled to 200 ℃ within 10-150 min, so that the nickel-titanium cable forms a first section of nickel-titanium cable and a second section of nickel-titanium cable connected with the first section of nickel-titanium cable, wherein the length ratio of the first section of nickel-titanium cable to the second section of nickel-titanium cable is 1: 12.75-1: 1, and the equivalent bending rigidity of the first section of nickel-titanium cable is smaller than 1/2 of the equivalent bending rigidity of the second section of nickel-titanium cable.

11. The method for preparing a transfer cable according to claim 10, wherein the step of heat treating the one end of the nitinol cable at 450-540 ℃ for at least 30min is heat treating in a vacuum environment or in a protective gas atmosphere.

12. A preparation method of a conveying cable is characterized by comprising the following steps:

providing a nickel titanium cable; and

13. A preparation method of a conveying cable is characterized by comprising the following steps:

providing a first section of nickel titanium cable and a second section of nickel titanium cable, wherein the length ratio of the first section of nickel titanium cable to the second section of nickel titanium cable is 1: 12.75-1: 1;

placing the first section of nickel-titanium cable in an environment with the temperature of 450-540 ℃ for heat treatment for at least 30min, and then cooling to 200 ℃ within 10-150 min to form a softened first section of nickel-titanium cable; or heating the first section of nickel-titanium cable to 450-540 ℃ by adopting laser, and then cooling to 200 ℃ within 10-150 min to form a softened first section of nickel-titanium cable; and