An experimental device for axial durability testing of vascular stents

Abstract

The present invention discloses an experimental device for axial durability testing of vascular stents, which relates to the technical field of biomedical experimental devices and includes an external support frame, an upper support cantilever, a lower support cantilever, a loading mechanism and a clamping mechanism; the upper support cantilever and the lower support cantilever are slidably arranged in the external support frame, and the upper support cantilever is located above the lower support cantilever; the upper support cantilever and the lower support cantilever are both provided with a clamping mechanism; the clamping mechanism is used to connect to the end of the vascular stent to be tested; the loading mechanism is transmission-connected to the upper support cantilever. The clamping device provides a fixed point and reduces deformation, thereby enabling direct clamping testing. Vascular stents of different diameters and lengths can be tested. The loading mechanism can achieve high-frequency loading, has a compact structure, high reliability, and can adapt to different loading requirements. Multiple groups of stents can provide consistent loads and environments, and the test results of each stent are comparable, which is conducive to obtaining effective test results and improving test efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of biomedical experimental devices, in particular to an experimental device for axial durability testing of a blood vessel stent. Background Art

[0002] After a stent is implanted into a blood vessel, it is subjected not only to the pressure of vascular pulsation, but also to multi-directional forces such as torsion, bending, stretching and compression. With the maturity of stent manufacturing technology and its widespread clinical application, the axial tensile and compressive fatigue of the stent has become the main indicator for evaluating the safety and effectiveness of vascular stents.

[0003] The axial durability of stents is typically tested by directly securing the stent and simulated vessel ends to a test fixture, or by placing the stent in a simulated vessel (without securing the stent ends). A loading mechanism then applies constant-frequency cyclic deformation, periodically stretching or compressing the stent to detect strut fractures. The test fixture must provide a secure and stable anchor point for the vessel model (and / or stent) and be capable of imparting quantifiable cyclic axial deformation to the stent.

[0004] Based on the above-mentioned testing requirements, the article "Research and Development of Fatigue Testing System for Vascular Stents" proposed a stent axial compression fatigue testing device. Stent loading joints are arranged on the upper and lower cantilevers respectively. The upper cantilever is driven to move up and down cyclically by the rotation of the eccentric wheel to perform cyclic compression on the stent. The position of the cam in the U-shaped groove is adjusted to confirm the compression amount of the upper baffle, thereby adjusting the compression size according to the length of the stent.

[0005] Chinese patent publication number CN113984559A discloses a device for synchronous tension, compression, and torsion fatigue testing of vascular stents. The device features a connecting plate connected to the output shaft of a linear motor, enabling reciprocating motion. Multiple claws are arranged around the outer periphery of the plate, with load sensors correspondingly positioned on these claws, along with a synchronous rotation mechanism. This device can simultaneously perform tension, compression, and torsion fatigue testing on multiple vascular stents. The height of the load sensors and the angular position of the claws can be adjusted during testing to accommodate stents of varying lengths.

[0006] The two test devices mentioned above have common problems. First, the stent loading joints both adopt a simple cylindrical structure, which is only suitable for simulating the fixation of the blood vessel end and is prone to slipping. In certain specific cases, such as the measurement of experimental deformation, direct fixation of the stent end is required, and the vascular stent has typical thin-walled parts that are easy to deform. The experimental device should provide a safe and firm fixing point and reduce deformation during the installation process, which the above device cannot achieve; secondly, this type of device needs to replace joints of different diameters when facing stents of different diameters, that is, it has poor adaptability to the size of the vascular stent and insufficient flexibility; in addition, the loading mechanism should provide high-frequency reciprocating motion with adjustable loading amplitude to continuously and consistently make the stent produce the expected length change to adapt to the simulation of different loading conditions. Summary of the Invention

[0007] In order to solve the above technical problems, the present invention provides an experimental device for axial durability testing of vascular stents. The device has a certain flexibility, can realize the positioning of stents of different diameters and lengths, and provide reliable clamping force. The above-mentioned cam loading mechanism is improved to provide reliable cyclic deformation, and the loading amplitude is continuously adjustable.

[0008] To achieve the above object, the present invention provides the following solutions:

[0009] The present invention provides an experimental device for axial durability testing of a vascular stent, comprising an external support frame, an upper support cantilever, a lower support cantilever, a loading mechanism and a clamping mechanism; the upper support cantilever and the lower support cantilever are slidably arranged in the external support frame, and the upper support cantilever is located above the lower support cantilever; the clamping mechanism is provided at the bottom of the upper support cantilever and the top of the lower support cantilever; the clamping mechanism is used to connect to the end of the vascular stent to be tested; the loading mechanism is arranged on the external support frame and is transmission-connected to the upper support cantilever.

[0010] Optionally, a guide rail is provided on both sides of the external support frame, and both ends of the upper support cantilever and the lower support cantilever are slidably connected to the guide rails respectively.

[0011] Optionally, the loading mechanism includes a cam assembly and a drive assembly; the cam assembly is transmission-connected to the upper support cantilever, and the drive assembly is used to drive the cam assembly.

[0012] Optionally, the cam assembly includes a camshaft outer ring, a camshaft inner ring, a camshaft frame and an adjusting screw; the camshaft outer ring includes a camshaft with a larger diameter and a circular ring structure with a smaller diameter, and one end of the camshaft is connected to one end of the circular ring structure; the camshaft inner ring is a rod-shaped structure, and the inner diameter of the camshaft outer ring is larger than the outer diameter of the camshaft inner ring; one end of the camshaft inner ring is transmission-connected to the drive assembly; the other end of the camshaft inner ring extends into the circular ring structure; the adjusting screw is threadedly connected to the side wall of the circular ring structure; the adjusting screw passes through the side wall of the circular ring structure and is connected to the camshaft inner ring; the camshaft is arranged in the camshaft frame; the camshaft frame is connected to the upper support cantilever.

[0013] Optionally, two through holes are provided on the top of the external support frame, and the bottom of the camshaft frame is connected to the upper support cantilever via two connecting rods, and the connecting rods pass through the through holes.

[0014] Optionally, the clamping mechanism includes a support seat, an adjusting nut, a bearing, a center shaft, an end cover, an elastic clamp, a wedge block and a spring; a transverse middle support is provided in the middle of the support seat, and a bottom support is provided at the bottom of the support seat; the middle support is provided with a middle mounting hole, and the bottom support is provided with a bottom mounting hole; the bearing is provided in the mounting hole of the middle support, and the adjusting nut is provided in the bearing; a plurality of grooves are provided in the bottom mounting hole along the circumferential direction, and a wedge block is provided in each of the grooves, and a wedge block is provided between the wedge block and the groove. The spring is provided; the end cover is provided on the bottom support; the upper part of the central shaft is provided with an external thread, and the external thread matches the internal thread on the adjusting nut; the lower part of the central shaft is provided with a plurality of wedge-shaped grooves along the circumference, and the wedge-shaped grooves match the wedge-shaped blocks; the upper part of the central shaft is assembled and connected with the adjusting nut, and the lower part of the central shaft passes through the end cover and then passes between the plurality of wedge-shaped blocks; the elastic clamp is provided on the outside of the plurality of wedge-shaped blocks, and the elastic clamp cooperates with the plurality of wedge-shaped blocks to be connected with the end of the vascular stent to be tested.

[0015] Optionally, a limiting block is provided at one end of the wedge block, and the limiting block matches the groove; the spring is provided between the side wall of the limiting block and the side wall of the groove.

[0016] Optionally, the exterior of the wedge block is an outer cylindrical surface, the interior of the wedge block is a trapezoidal block, and the length of one end of the wedge block is smaller than the length of the other end.

[0017] Optionally, four grooves are arranged circumferentially in the bottom mounting hole.

[0018] Optionally, a slide rail is provided at the bottom of the external support frame, and a slide is provided on one side of the lower support cantilever, and the slide is slidably connected to the slide rail.

[0019] Compared with the prior art, the present invention has achieved the following technical effects:

[0020] 1. The clamping device provides a safe and secure fixing point and reduces deformation during the installation process. It can realize direct clamping testing of thin-walled and fragile parts such as vascular stents, meeting the needs of specific scenarios.

[0021] 2. The device has a certain degree of flexibility and can be used to test vascular stents of different diameters and lengths.

[0022] 3. The loading mechanism adopts an eccentric wheel, which can realize high-frequency loading, and has a compact structure and high reliability. At the same time, the eccentric adjustable mechanism improves the flexibility of the loading mechanism to adapt to different loading requirements.

[0023] 4. Consistent simulated loads and simulated environments can be provided for multiple groups of brackets, and the test results of each bracket are comparable, which is conducive to obtaining effective test results and improving test efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 Schematic diagram of the structure of the experimental device for axial durability testing of a vascular stent according to the present invention;

[0026] Figure 2 Schematic diagram of the structure of the loading mechanism in the experimental device for axial durability testing of a vascular stent according to the present invention;

[0027] Figure 3 Schematic diagram of the structure of the cam in the experimental device for axial durability testing of a vascular stent according to the present invention;

[0028] Figure 4 Schematic diagram of the structure of the clamping mechanism in the experimental device for axial durability testing of a vascular stent according to the present invention;

[0029] Figure 5 Schematic diagram of the partial structure of the clamping mechanism in the experimental device for axial durability testing of a vascular stent according to the present invention;

[0030] Figure 6This is a schematic diagram of the structural decomposition of the clamping mechanism in the experimental device for axial durability testing of a vascular stent according to the present invention;

[0031] Figure 7 Schematic diagram of the structure of the central axis of the experimental device for axial durability testing of a vascular stent according to the present invention;

[0032] Figure 8 This is a schematic structural diagram of a wedge block in the experimental device for axial durability testing of a vascular stent according to the present invention.

[0033] Explanation of reference numerals: 1. motor; 2. motor support; 3. camshaft; 4. camshaft frame; 5. clamping mechanism; 6. slide; 7. slide guide rail; 8. lower support cantilever; 9. vascular stent; 10. external support frame; 11. upper support cantilever; 12. connecting rod; 13. coupling;

[0034] 31. Camshaft outer ring; 32. Camshaft inner ring; 33. Adjusting screw;

[0035] 51. Support seat; 52. Adjusting nut; 53. Bearing; 54. Center shaft; 55. End cover; 56. Elastic clamp; 57. Wedge block; 58. Spring. DETAILED DESCRIPTION

[0036] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0037] like Figures 1 to 8 As shown, this embodiment provides an experimental device for axial durability testing of a vascular stent, comprising an external support frame 10, an upper support cantilever 11, a lower support cantilever 8, a loading mechanism and a clamping mechanism 5; the upper support cantilever 11 and the lower support cantilever 8 are slidably arranged in the external support frame 10, and the upper support cantilever 11 is located above the lower support cantilever 8; a clamping mechanism 5 is provided at the bottom of the upper support cantilever 11 and the top of the lower support cantilever 8; the clamping mechanism 5 is used to connect to the end of the vascular stent 9 to be tested; the loading mechanism is arranged on the external support frame 10 and is transmission-connected to the upper support cantilever 11.

[0038] In this specific embodiment, the external support frame 10 is used to support and position the entire device. The external support frame 10 is a square frame structure. Two through holes are opened on the top of the external support frame 10. A guide rail is provided on both sides of the external support frame 10. The two ends of the upper support cantilever 11 and the lower support cantilever 8 are respectively slidably connected to the guide rails, and the upper support cantilever 11 and the lower support cantilever 8 are guided up and down by the guide rails.

[0039] The loading mechanism includes a cam assembly and a drive assembly; the cam assembly is connected to the upper support cantilever 11 by transmission, and the drive assembly is used to drive the cam assembly. The drive assembly includes a motor 1 and a motor support 2.

[0040] The cam assembly includes a camshaft outer ring 31, a camshaft inner ring 32, a camshaft frame 4 and two adjusting screws 33; the camshaft outer ring 31 includes a camshaft 3 with a larger diameter and a circular ring structure with a smaller diameter, and one end of the camshaft 3 is connected to one end of the circular ring structure; the camshaft inner ring 32 is a rod-shaped structure, and the inner diameter of the camshaft outer ring 31 is larger than the outer diameter of the camshaft inner ring 32; one end of the camshaft inner ring 32 is transmission-connected to the drive assembly; the other end of the camshaft inner ring 32 extends into the circular ring structure; two threaded holes are provided on the side wall of the circular ring structure, and the two threaded holes are coaxially arranged, and each adjusting screw 33 is assembled and connected to a threaded hole; the adjusting screw 33 passes through the side wall of the circular ring structure through the threaded hole and is connected to the camshaft inner ring 32; the camshaft 3 is arranged in the camshaft frame 4; the camshaft frame 4 is connected to the upper support cantilever 11. More specifically, two holes are provided on the camshaft inner ring 32 , and the adjusting screw 33 passes through the side wall of the annular structure through the threaded hole and then extends into the hole and extends to the bottom of the hole, so that the end of the adjusting screw 33 contacts the bottom of the hole.

[0041] The motor 1 is mounted on the top of the external support frame 10 via the motor support 2 , and the output shaft of the motor 1 is connected to the end of the camshaft inner ring 32 via the coupling 13 .

[0042] By adjusting the distance between the two adjusting screws 33 screwed into the ring structure, the distance between the center of the camshaft inner ring 32 and the center of the camshaft outer ring 31 can be adjusted to adjust the eccentricity to meet different loading requirements.

[0043] The bottom of the camshaft frame 4 is connected to the upper support cantilever 11 via two connecting rods 12 , and the connecting rods 12 pass through the through holes at the top of the external support frame 10 .

[0044] Motor 1 rotates, transmitting its rotational output to camshaft outer ring 31 through coupling 13 and camshaft inner ring 32. Camshaft outer ring 31 rotates within camshaft frame 4, causing camshaft frame 4 to move up and down. This, in turn, drives upper support arm 11 up and down via connecting rod 12. The range of motion of upper support arm 11 is adjusted by adjusting the eccentricity of adjustment screw 33.

[0045] The clamping mechanism 5 includes a support seat 51, an adjusting nut 52, a bearing 53, a central shaft 54, an end cover 55, an elastic clamp 56, a wedge block 57 and a spring 58; a transverse middle support is provided in the middle of the support seat 51, and a bottom support is provided at the bottom of the support seat 51.

[0046] The middle support is provided with a middle mounting hole, and the bottom support is provided with a bottom mounting hole.

[0047] The bearing 53 is disposed in the mounting hole of the middle support, and the adjusting nut 52 is disposed in the bearing 53 .

[0048] Four grooves are circumferentially arranged in the bottom mounting hole. A wedge block 57 is arranged in each groove, and a spring 58 is arranged between the wedge block 57 and the groove.

[0049] The end cap 55 is arranged on the bottom support and is used to limit the axial displacement of the wedge block 57, to prevent the wedge block 57 from being separated from the groove when the lower portion of the wedge block 57 is inserted into the vascular stent 9, and to perform sealing at the same time.

[0050] An external thread is provided on the upper portion of the central shaft 54, which matches the internal thread on the adjusting nut 52; a plurality of wedge-shaped grooves are provided circumferentially on the middle and lower portion of the central shaft 54, which match the wedge blocks 57; the upper portion of the central shaft 54 is assembled and connected to the adjusting nut 52, and the lower portion of the central shaft 54 passes through the end cover 55 and passes between the plurality of wedge blocks 57; an elastic clamp 56 is sleeved on the outside of the plurality of wedge blocks 57, and the elastic clamp 56 cooperates with the plurality of wedge blocks 57 to connect with the end portion of the vascular stent 9 to be tested.

[0051] More specifically, a stopper is provided at one end of the wedge block 57, which mates with the groove. A spring 58 is positioned between the sidewalls of the stopper and the groove. The wedge block 57 has an outer cylindrical surface, while its interior is a trapezoidal block. One end of the wedge block 57 is shorter than the other end. Furthermore, a receiving hole is provided on the closed end surface of the groove. One end of the spring 58 extends into the hole, while the other end of the spring 58 contacts the stopper of the wedge block 57. The elastic force of the spring 58 pushes the wedge block 57 against the central shaft 54, achieving close contact between the wedge block 57 and the central shaft 54.

[0052] In a further embodiment, the lower portion of the central shaft 54 is a conical structure.

[0053] A slide rail 7 is provided at the bottom of the outer support frame 10, and a slide 6 is provided on one side of the lower support cantilever 8. The slide 6 is slidably connected to the slide rail 7. The slide 6 can slide along the slide rail 7 and can be locked. The position of the lower support cantilever 8 can be adjusted according to the length of the vascular stent 9. More specifically, a locking screw is provided on the slide 6. Loosening the locking screw allows the slide 6 to slide along the slide rail 7, and tightening the locking screw secures the slide 6 to the slide rail 7.

[0054] The operating method of the experimental device for the axial durability test of the vascular stent in this embodiment is as follows:

[0055] ① According to the loading deformation, adjust the cam eccentricity, determine the reciprocating motion amplitude, and adjust the output of motor 1 according to the loading frequency;

[0056] ② Place the vascular stent 9 above the lower clamping device, adjust the adjusting nut 52 to move the central axis 54 upward or downward until the four wedge blocks 57 support the inner wall of the vascular stent 9, and then adjust the bolts of the elastic clamp 56 to achieve clamping.

[0057] ③ According to the length of the vascular stent 9, adjust the slide 6 so that the lower support cantilever 8 reaches the appropriate position and lock it. Use the same clamping method on the upper clamping device to determine the gauge length;

[0058] ④Start fatigue test.

[0059] It should be noted that it is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, from all perspectives, the embodiments should be regarded as illustrative and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the foregoing description. It is intended that all changes that fall within the meaning and range of equivalents of the claims be included in the present invention, and any reference signs in the claims should not be construed as limiting the claims to which they relate.

[0060] This specification uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. An experimental device for axial durability testing of vascular stents, characterized in that: It includes an external support frame, an upper support cantilever, a lower support cantilever, a loading mechanism and a clamping mechanism; the upper support cantilever and the lower support cantilever are slidably arranged in the external support frame, and the upper support cantilever is located above the lower support cantilever; the clamping mechanism is provided at the bottom of the upper support cantilever and the top of the lower support cantilever; the clamping mechanism is used to connect with the end of the vascular stent to be tested; the loading mechanism is provided on the external support frame and is transmission-connected to the upper support cantilever; The clamping mechanism includes a support seat, an adjusting nut, a bearing, a central shaft, an end cover, an elastic clamp, a wedge block and a spring; a transverse central support is provided in the middle of the support seat, and a bottom support is provided at the bottom of the support seat; the central support is provided with a central mounting hole, and the bottom support is provided with a bottom mounting hole; the bearing is provided in the mounting hole of the central support, and the adjusting nut is provided in the bearing; a plurality of grooves are provided in the bottom mounting hole along the circumference, and a wedge block is provided in each of the grooves, and a wedge block is provided between the wedge block and the groove The spring is provided; the end cap is arranged on the bottom support; the upper portion of the central shaft is provided with an external thread, and the external thread matches the internal thread on the adjusting nut; the middle and lower portion of the central shaft is provided with a plurality of wedge-shaped grooves along the circumference, and the wedge-shaped grooves match the wedge-shaped blocks; the upper portion of the central shaft is assembled and connected with the adjusting nut, and the lower portion of the central shaft passes through the end cap and then passes between the plurality of wedge-shaped blocks; the elastic clamp is sleeved on the outside of the plurality of wedge-shaped blocks, and the elastic clamp cooperates with the plurality of wedge-shaped blocks to connect with the end of the vascular stent to be tested; A limiting block is provided at one end of the wedge-shaped block, and the limiting block matches the groove; the spring is provided between the side wall of the limiting block and the side wall of the groove.

2. The experimental device for axial durability testing of a vascular stent according to claim 1, characterized in that: A guide rail is respectively provided on both sides of the outer support frame, and both ends of the upper support cantilever and the lower support cantilever are respectively slidably connected to the guide rail.

3. The experimental device for axial durability testing of a vascular stent according to claim 1, characterized in that: The loading mechanism includes a cam assembly and a driving assembly; the cam assembly is transmission-connected to the upper supporting cantilever, and the driving assembly is used to drive the cam assembly.

4. The experimental device for axial durability testing of a vascular stent according to claim 3, characterized in that: The cam assembly includes a camshaft outer ring, a camshaft inner ring, a camshaft frame and an adjusting screw; the camshaft outer ring includes a camshaft and a circular ring structure, one end of the camshaft is connected to one end of the circular ring structure; the camshaft inner ring is a rod-shaped structure, and the inner diameter of the camshaft outer ring is larger than the outer diameter of the camshaft inner ring; one end of the camshaft inner ring is transmission-connected to the drive assembly; the other end of the camshaft inner ring extends into the circular ring structure; the adjusting screw is threadedly connected to the side wall of the circular ring structure; the adjusting screw passes through the side wall of the circular ring structure and is connected to the camshaft inner ring; the camshaft is arranged in the camshaft frame; the camshaft frame is connected to the upper support cantilever.

5. The experimental device for axial durability testing of a vascular stent according to claim 4, characterized in that: Two through holes are provided on the top of the external support frame. The bottom of the camshaft frame is connected to the upper support cantilever via two connecting rods, and the connecting rods pass through the through holes.

6. The experimental device for axial durability testing of a vascular stent according to claim 1, characterized in that: The outside of the wedge block is an outer cylindrical surface, the inside of the wedge block is a trapezoidal block, and the length of one end of the wedge block is smaller than the length of the other end.

7. The experimental device for axial durability testing of a vascular stent according to claim 1, characterized in that: Four grooves are arranged in the bottom mounting hole along the circumferential direction.

8. The experimental device for axial durability testing of a vascular stent according to claim 1, characterized in that: A slide rail is provided at the bottom of the outer support frame, and a slide is provided on one side of the lower support cantilever. The slide is slidably connected to the slide rail.

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