阅读说明：本技术 一种固定锁紧结构及医用导管、血泵 (Fixed locking structure, medical catheter and blood pump ) 是由 唐智荣 刘智勇 徐玲艳 于 2021-11-03 设计创作，主要内容包括：本发明公开一种固定锁紧结构,包括套设在导管外的内筒体、卡盘和外筒体；导管包括驱动轴和位于驱动轴外部的鞘管；卡盘为筒状弹性体；外筒体的远端形成有容纳卡盘的第一腔体,内筒体的近端与外筒体的远端通过连接结构连接,卡盘的一端与内筒体的近端抵接,另一端与第一腔体的内壁抵接；卡盘的两端均设置有卡紧部,卡紧部沿周向等间距设置有多个槽口,内筒体和外筒体与卡紧部抵接处形成有压接部。本发明设置两端具有卡紧部的卡盘,内筒体和外筒体设置与卡紧部抵接的压接部；卡紧部沿周向设置有槽口,使得鞘管在槽口处向外侧形变,鞘管的形变量可控；卡紧部与压接部呈圆台结构,通过圆台面抵接,在轴向锁紧时,给予径向压力,保证固定锁紧效果。(The invention discloses a fixed locking structure, which comprises an inner cylinder, a chuck and an outer cylinder, wherein the inner cylinder, the chuck and the outer cylinder are sleeved outside a conduit; the catheter comprises a driving shaft and a sheath tube positioned outside the driving shaft; the chuck is a cylindrical elastic body; a first cavity for accommodating the chuck is formed at the far end of the outer barrel, the near end of the inner barrel is connected with the far end of the outer barrel through a connecting structure, one end of the chuck is abutted against the near end of the inner barrel, and the other end of the chuck is abutted against the inner wall of the first cavity; the both ends of chuck all are provided with the clamping part, and the clamping part is provided with a plurality of notches along circumference equidistant, and interior barrel and outer barrel are formed with the clamping part butt department and press from both sides the portion. The invention is provided with a chuck with clamping parts at two ends, and an inner cylinder and an outer cylinder are provided with a crimping part which is abutted against the clamping parts; the clamping part is provided with a notch along the circumferential direction, so that the sheath tube deforms outwards at the notch, and the deformation amount of the sheath tube is controllable; the clamping part and the crimping part are of a circular truncated cone structure, and the clamping part is abutted against the circular truncated cone surface, so that radial pressure is applied to the clamping part when the clamping part and the crimping part are axially locked, and a fixed locking effect is guaranteed.)

1. A fixed locking structure is characterized by comprising an inner cylinder, a chuck and an outer cylinder which are sleeved outside a guide pipe, wherein the guide pipe comprises a driving shaft and a sheath pipe positioned outside the driving shaft; the chuck is a cylindrical elastic body; a first cavity for accommodating the chuck is formed at the far end of the outer cylinder body, the near end of the inner cylinder body is connected with the far end of the outer cylinder body through a connecting structure, one end of the chuck is abutted against the near end of the inner cylinder body, and the other end of the chuck is abutted against the inner wall of the first cavity; a first clamping part is formed at one end, abutted against the inner cylinder body, of the chuck, a plurality of first notches are formed in the first clamping part at equal intervals in the circumferential direction, and a first pressing part abutted against the first clamping part is formed on the inner wall of the near end of the inner cylinder body; a second clamping part is formed at one end, abutted against the outer cylinder, of the chuck, a plurality of second notches are formed in the second clamping part at equal intervals in the circumferential direction, and a second pressing part abutted against the second clamping part is formed on the inner wall of the near end of the first cavity; when the near end of the inner barrel body is connected with the far end of the outer barrel body, the first clamping part is pressed by the first pressing part to shrink inwards, the second pressing part is pressed by the second pressing part to shrink inwards, and the sheath tube is fixedly locked while being deformed outwards at the notch.

2. The securing lock structure according to claim 1, wherein the first notch and the second notch are both provided in an axial direction of the chuck; the first notch and the second notch are arranged in a staggered mode.

3. A fixing and locking structure as recited in claim 1, wherein the first clamping portion, the second clamping portion, the first crimping portion and the second crimping portion are all in a truncated cone shape, the apex angle of the cone where the first clamping portion is located is smaller than the apex angle of the cone where the first crimping portion is located, and the apex angle of the cone where the second clamping portion is located is smaller than the apex angle of the cone where the second crimping portion is located.

4. The fastening lock structure of claim 1, wherein the connection structure is a threaded connection structure comprising an external thread provided on an outer wall of the proximal end of the inner barrel and an internal thread provided on an inner wall of the distal end of the outer barrel, the external thread matching the internal thread, the proximal end of the inner barrel being gradually screwed into the distal end of the outer barrel.

5. The fixed locking structure of claim 1, wherein the connecting structure is a snap connecting structure, the snap connecting structure comprises a positioning pin disposed on the outer wall of the near end of the inner cylinder and an annular groove disposed on the inner wall of the far end of the outer cylinder, the annular groove is circumferentially disposed along the inner wall of the outer cylinder, the number of the annular grooves is at least one, the inner wall of the far end of the outer cylinder is axially provided with a guide groove, the guide groove is communicated with the annular groove, the positioning pin axially slides into the annular groove through the guide groove and is rotationally locked into the annular groove for fixing, and the inner cylinder is locked into the annular groove of the outer cylinder through the positioning pin.

6. The fixation and locking structure of claim 1, wherein the minimum inner diameter of the sheath of the catheter after the chuck is compressed and locked for fixation is estimated by the following calculation formula:

D=d-d×n×(arcsin(w/d))/π-2δ；

wherein, D: the inner diameter of the sheath pipe after the chuck is compressed; d: the chuck compresses the front inside diameter; n: the number of the notches; w: the width of the notch; δ: the thickness of the sheath tube wall.

7. The fixation and locking structure of claim 1, wherein the number of said notches is 2-12 when the sheath size of said catheter is 4fr-14 fr.

8. The fixation locking structure of claim 7, wherein the slot width is 0.18mm to 0.78mm when the sheath size of the catheter is 9 fr.

9. The fastening structure of claim 1, wherein the outer walls of the outer cylinder and the inner cylinder are provided with anti-slip threads.

10. A medical catheter comprising a drive shaft and a sheath external to the drive shaft, the sheath being externally provided with a fixation lock structure as claimed in any one of claims 1 to 9 for securing the sheath.

11. A blood pump comprising a pump device, a catheter and an extracorporeal drive device, the catheter comprising a drive shaft and a sheath located outside the drive shaft, the extracorporeal drive device driving the pump device via the drive shaft, characterized in that the sheath is externally provided with a fixation lock structure according to any one of claims 1 to 9 for fixing the sheath.

Technical Field

The invention relates to the field of medical instruments, in particular to a fixing and locking structure, a medical catheter and a blood pump.

Background

The clinical route of use of percutaneous catheter pumps is to draw blood from the ventricle, through a catheter across the valve, and into the artery from the outflow port, which determines the distribution of the suction and outflow ports on either side of the valve. When the product is implanted, the suction inlet and the outflow outlet can be accurately distributed on two sides of the valve under the guidance of DSA (Digital subtraction angiography). After the product is put in place, the suture system and the catheter are fixedly connected through the locking structure, and then the whole catheter body and the human body are fixed through the suture system. If the locking structure and the catheter body are not reliably locked, the catheter is stressed to shift in the process of assisting blood circulation, the arrangement that the suction inlet and the outflow port are distributed on two sides of the valve can be directly changed, and the product loses clinical effect. On the other hand, when the sheath pipe deformation at the catheter locking part is uncontrollable, the internal structure of the sheath pipe is affected. In severe cases, this can lead to product failure and failure of the procedure. In order to find the displacement of the catheter body in time, foreign products of the same kind develop a very complicated in-vivo displacement alarm system, but the main function of the alarm is only to remind a doctor to remedy the unexpected displacement of the catheter, and the best way is to provide reliable locking force to prevent the displacement.

The locking structure described in chinese patent CN109793975A is that when the locking cap is screwed to the locking base, the elastic locking ring 5 is axially extruded, and radial compression is formed by the volume conservation principle to achieve the purpose of locking, and the locking manner has the following problems: in this locking structure, when the elastic locking ring is radially compressed, the amount of radial deformation of the elastic locking ring is difficult to control, and the deformation of the sheath 4 of the corresponding catheter is difficult to predict, as shown in fig. 1. This situation will lead to the following problems: 1. the locking force is unstable or the consistency of the locking force is poor; when the elastic locking ring 5 is axially extruded, because the pipe wall of the locking ring 5 deforms and the deformation cannot be predicted, the shapes of the contact surfaces of the locking ring 5 and the sheath pipe 4 are different, and when the locking cap and the locking base are screwed into the same displacement, the locking forces generated at different positions of the outer wall of the locking ring 5 are different; 2. internal collapse is caused during locking; in the use process, the deformation of the tube wall of the locking ring 5 is not controlled, so that in order to achieve the required locking force, the local deformation of the wall of the sheath tube 4 is overlarge, and unexpected structural changes such as collapse and the like occur in the catheter; 3. after locking, the minimum inner diameter of the sheath tube is small; in clinical use of a percutaneous interventional blood pump, the catheter comprises at least an inner mechanical drive shaft and an outer sheath 4, and it is desirable to maintain the dimensions of the inner wall of the sheath 4 when locked to ensure proper operation of the mechanical drive shaft.

The locking structure described in chinese patent CN101224145B is that when the locking cap is screwed to the connecting piece, the locking head 9 is axially extruded, and the multi-petal contracting structure that the locking head 9 can contract locks the conveying conduit after contracting; in the process of forced extrusion, the locking head proximal end 91 is forced to deform to drive the petal-shaped structure of the locking head distal end 92 to contract, therefore, the locking head 9 is designed to be thick at the distal end and thin at the proximal end, and the separation groove of the multi-petal contraction structure is longer in length and extends from the distal end to the proximal end. The thinner proximal end and longer separation channels are easily deformed to effect distal end retraction as shown in fig. 2. Each lamella of the locking head 9 multi-lamella structure forms a cantilever structure, greater pressure needs to be applied to the near end to enable the far end to achieve locking, stress concentration of the locking head near end 91 is caused, the stress concentration of the locking head near end 91 is easy to break and damage, meanwhile, the locking head far end 92 needs to achieve the force for locking the catheter sheath tube 4, the lamella-shaped structure of the locking head far end 92 needs to shrink greatly, deformation of the sheath tube 4 is caused to be large, the space in the catheter is small, and the catheter is not suitable for being used in occasions where the catheter contains a mechanical transmission shaft.

Thus, there is a need for improvements and enhancements in the art.

Disclosure of Invention

The invention aims to solve the technical problem of providing a fixing and locking structure, a medical catheter and a blood pump, which are fixedly locked outside a sheath of the catheter through a chuck with a notch, so that the deformation of the sheath is controllable while the fixing and locking effect is ensured.

The invention adopts the technical scheme that a fixed locking structure is provided for solving the technical problems, and comprises an inner cylinder body, a chuck and an outer cylinder body which are sleeved outside a guide pipe, wherein the guide pipe comprises a driving shaft and a sheath pipe positioned outside the driving shaft; the chuck is a cylindrical elastic body; a first cavity for accommodating the chuck is formed at the far end of the outer cylinder body, the near end of the inner cylinder body is connected with the far end of the outer cylinder body through a connecting structure, one end of the chuck is abutted against the near end of the inner cylinder body, and the other end of the chuck is abutted against the inner wall of the first cavity; a first clamping part is formed at one end, abutted against the inner cylinder body, of the chuck, a plurality of first notches are formed in the first clamping part at equal intervals in the circumferential direction, and a first pressing part abutted against the first clamping part is formed on the inner wall of the near end of the inner cylinder body; a second clamping part is formed at one end, abutted against the outer cylinder, of the chuck, a plurality of second notches are formed in the second clamping part at equal intervals in the circumferential direction, and a second pressing part abutted against the second clamping part is formed on the inner wall of the near end of the first cavity; when the near end of the inner barrel body is connected with the far end of the outer barrel body, the first clamping part is pressed by the first pressing part to shrink inwards, the second pressing part is pressed by the second pressing part to shrink inwards, and the sheath tube is fixedly locked while being deformed outwards at the notch.

Further, the first notch and the second notch are arranged along the axial direction of the chuck; the first notch and the second notch are arranged in a staggered mode.

Further, first clamping part, second clamping part, first crimping portion and second crimping portion all are round platform shape, the apex angle of the circular cone at first clamping part place is less than the apex angle of the circular cone at first crimping portion place, the apex angle of the circular cone at second clamping part place is less than the apex angle of the circular cone at second crimping portion place.

Further, connection structure is threaded connection structure, threaded connection structure is including setting up the external screw thread of barrel near-end outer wall and setting up the internal thread at outer barrel distal end inner wall including, the external screw thread matches with the internal thread, the near-end of interior barrel is gradually screwed in the distal end of outer barrel.

Further, connection structure is buckle connection structure, buckle connection structure is including setting up the locating pin of barrel near-end outer wall and setting up the annular at outer barrel distal end inner wall including, the annular sets up along outer barrel inner wall circumference, annular quantity is one at least, outer barrel distal end inner wall axial is provided with the guide way, guide way intercommunication annular, the locating pin axial slides to the annular in through the guide way and the rotatory card goes into the annular and fixes, the inner barrel passes through the annular of locating pin card income outer barrel.

Further, the minimum inner diameter of the sheath of the catheter after the chuck is compressed, locked and fixed can be estimated through the following calculation formula: d = D-D × n × (arcsin (w/D))/pi-2 δ, wherein D: the inner diameter of the sheath pipe after the chuck is compressed; d: the chuck compresses the front inside diameter; n: the number of the notches; w: the width of the notch; δ: the thickness of the sheath tube wall.

Further, when the sheath size of the catheter is 4fr-11fr, the number of the notches is 2-12.

Further, when the sheath size of the catheter is 9fr, the width of the notch is 0.18mm-0.78 mm.

Furthermore, the outer wall of outer barrel and interior barrel is provided with anti-skidding line.

The second technical solution adopted to solve the above technical problems is to provide a medical catheter, which includes a driving shaft and a sheath tube located outside the driving shaft, wherein the sheath tube is provided with the above fixing and locking structure for fixing the sheath tube.

A third technical solution adopted by the present invention to solve the above technical problem is to provide a blood pump, which includes a pump device, a catheter and an extracorporeal drive device, wherein the catheter includes a drive shaft and a sheath located outside the drive shaft, and the extracorporeal drive device drives the pump device through the drive shaft, and is characterized in that the sheath is externally provided with the above fixing and locking structure for fixing the sheath.

Compared with the prior art, the invention has the following beneficial effects: the invention provides a fixed locking structure, a medical catheter and a blood pump, wherein a chuck with clamping parts at two ends is arranged, and the clamping parts are pressed by a crimping part of an inner cylinder body and an outer cylinder body which are abutted against the clamping parts to fixedly lock a sheath tube of the catheter; the clamping part is provided with a notch along the circumferential direction, so that the sheath tube deforms outwards at the notch, the deformation amount of the sheath tube is controllable, and the minimum inner diameter of the deformed sheath tube can be estimated; the clamping part and the crimping part are of a circular truncated cone structure and are abutted against each other through the circular truncated cone surface, so that when the axial locking is carried out, radial pressure can be given, sufficient static friction is generated, the fixed locking effect is ensured, and meanwhile, the function of the driving shaft can be fully ensured.

Drawings

FIG. 1 is a cross-sectional view of a prior art locking structure during locking;

FIG. 2 is a schematic view of a locking head of another locking structure;

FIG. 3 is an exploded view of a secure locking structure according to an embodiment of the present invention;

FIG. 4 is a disassembled sectional view of a securing structure according to an embodiment of the present invention;

FIG. 5 is a sectional view of the sheath locked by the fixing and locking structure according to the embodiment of the present invention;

FIG. 6 is a schematic view illustrating a sheath locked by the fixing and locking structure according to an embodiment of the present invention;

FIG. 7 is a cross-sectional view of a sheath locked by the fixing and locking structure according to an embodiment of the present invention;

FIG. 8 is an exploded view of a snap-fit fastening arrangement according to an embodiment of the present invention;

FIG. 9 is a disassembled cross-sectional view of a snap-fit fastening structure in accordance with an embodiment of the present invention;

FIG. 10 is a schematic view of a medical catheter in accordance with an embodiment of the present invention;

fig. 11 is a schematic structural view of a blood pump according to an embodiment of the present invention.

In the figure:

1. an inner cylinder; 2. a chuck; 3. an outer cylinder; 4. a sheath tube; 5. locking a ring; 6. a drive shaft; 7. a pump device; 8. an extracorporeal drive device; 9. a locking head; 91. a proximal end of the locking head; 92. a locking head distal end; 11. a first crimping part; 12. an external thread; 13. positioning pins; 21. a first clamping part; 22. a first notch; 23. a second clamping part; 24. a second notch; 31. a first cavity; 32. a second crimping part; 33. an internal thread; 34. a ring groove; 35. a guide groove.

In the figure:

1. an inner cylinder; 2. a chuck; 3. an outer cylinder; 4. a sheath tube; 5. locking a ring; 6. a drive shaft; 7. a pump device; 8. an extracorporeal drive device; 9. a locking head; 91. a proximal end of the locking head; 92. a locking head distal end; 11. a first crimping part; 12. an external thread; 13. positioning pins; 21. a first clamping part; 22. a first notch; 23. a second clamping part; 24. a second notch; 31. a first cavity; 32. a second crimping part; 33. an internal thread; 34. a ring groove; 35. a guide groove.

Detailed Description

The invention is further described below with reference to the figures and examples.

FIG. 3 is an exploded view of a secure locking structure according to an embodiment of the present invention; FIG. 4 is a disassembled sectional view of a securing structure according to an embodiment of the present invention; FIG. 5 is a sectional view of the sheath locked by the fixing and locking structure according to the embodiment of the present invention; FIG. 6 is a schematic view illustrating a sheath locked by the fixing and locking structure according to an embodiment of the present invention; fig. 7 is a cross-sectional view of the sheath locked by the fixing and locking structure according to the embodiment of the present invention.

Referring to fig. 3-7, the fixing and locking structure of the embodiment of the present invention includes an inner cylinder 1, a chuck 2 and an outer cylinder 3, which are sleeved outside the conduit; the chuck 2 is a cylindrical elastic body; the distal end of outer barrel 3 is formed with the first cavity 31 that holds chuck 2, and the near-end of interior barrel 1 passes through connection structure with the distal end of outer barrel 3 to be connected, the near-end butt of the one end of chuck 2 and interior barrel 1, the inner wall butt of the other end and first cavity 31.

The chuck 2 is a cylindrical elastic body, which means that the chuck 2 is made of elastic material, the chuck 2 is made of nylon, rubber, polyethylene or a combination of rubber and polyethylene, and the hardness of the chuck 2 is greater than that of the sheath 4. The material of the inner cylinder body 1 and the outer cylinder body 3 is High Density Polyethylene (HDPE), Low Density Polyethylene (LDPE) or Linear Low Density Polyethylene (LLDPE).

Specifically, the two ends of the chuck 2 are respectively provided with a clamping part, the clamping parts are circumferentially provided with a plurality of notches, and the abutting parts of the inner cylinder 1 and the outer cylinder 3 with the clamping parts are provided with compression parts; when the near end of the inner cylinder body 1 is connected with the far end of the outer cylinder body 3, the crimping part presses the clamping part to contract inwards, and the sheath tube 4 of the catheter deforms outwards at the notch and is fixed and locked. The deformation position is reserved in advance to the notch for 4 deformation directions of sheath pipe are to the outside, when guaranteeing to reach required biggest stiction, and the internal diameter after 4 deformation of sheath pipe is even controllable, and the minimum internal diameter is big.

Specifically, a first clamping part 21 is formed at one end of the chuck 2, which is abutted to the inner cylinder 1, a plurality of first notches 22 are circumferentially arranged on the first clamping part 21, and a first crimping part 11 abutted to the first clamping part 21 is formed on the inner wall of the near end of the inner cylinder 1; a second clamping part 23 is formed at one end of the chuck 2, which is abutted to the outer cylinder 3, a plurality of second notches 24 are circumferentially arranged on the second clamping part 23, and a second crimping part 32 abutted to the second clamping part 23 is formed on the inner wall of the near end of the first cavity 31. The chucks 2 with the clamping parts are symmetrically arranged at the two ends, so that the whole stress at the two ends of the chucks 2 is uniform, the local stress is reduced, and the maximum deformation is generated at the maximum normal stress position, thereby reducing the deformation quantity. Compare with the locking structure in prior art figure 2, locking head near-end 91 atress warp and drive the lamella structure shrink locking of locking head distal end 92, and locking head distal end 92 will reach the same locking dynamics, and the lamella structure of locking head distal end 92 now needs to have bigger shrink to chuck 2 structure that both ends symmetry locked, leads to sheath pipe 4 to warp greatly for the space is littleer in the pipe, is not suitable for the inside occasion that contains mechanical transmission shaft of pipe to use. Meanwhile, the locking head 9 is of a structure with a thick far end and a thin near end, the stress concentration part of the near end is easy to break and damage, the problem of wall thickness does not need to be considered due to the symmetrical structure of the chuck 2, and compared with the locking head 9, the structure is simpler, the manufacture is easy, and the production cost is reduced.

Specifically, the first clamping part 21 and the first crimping part 11 are both in a truncated cone shape, and the second clamping part 23 and the second crimping part 32 are both in a truncated cone shape. Through the abutting of the round table surfaces, when the first clamping part 21 and the second clamping part 23 of the chuck 2 are locked in the axial direction, radial pressure can be applied to the sheath tube 4, sufficient static friction is generated, and the fixing and locking effect is ensured; the vertex angle of the cone where the first clamping part 21 is located is smaller than that of the cone where the first crimping part 11 is located; the vertex angle of the cone where the second clamping part 23 is located is smaller than that of the cone where the second crimping part 32 is located; make chucking part and crimping portion form line contact, avoid the big problem of frictional force that the face contact leads to.

Specifically, the first notch 22 and the second notch 24 are both provided in the axial direction of the chuck 2; the first notch 22 is offset from the second notch 24.

Alternatively, the plurality of first notches 22 are provided at equal intervals in the first clamping part 21, and the plurality of second notches 24 are provided at equal intervals in the second clamping part 23. The equidistant arrangement can make the stress of the locking process more uniform.

In other embodiments, the first notch 22 and the second notch 24 may be disposed opposite to each other and on the same central axis.

The catheter comprises a driving shaft 6 and a sheath tube 4 arranged outside the driving shaft 6, wherein the driving shaft 6 is connected with an external driving device for driving the pump device, so that enough space must be reserved in the sheath tube to allow the driving shaft 6 to rotate for driving the pump device, and therefore, when the fixed locking structure is fixed outside the sheath tube 4, the space in the sheath tube 4 needs to be ensured to be controllable and predictable. In fig. 1 of the prior art, when the locking ring 5 locks the sheath tube 4 of the catheter, the deformation of the sheath tube 4 is not controlled, which causes unexpected structural changes such as collapse of the sheath tube 4, and thus the space inside the sheath tube 4 is not controlled.

It should be noted that, the fixing and locking structure according to the embodiment of the present application is sleeved outside the catheter, specifically, is sleeved outside a sheath on the catheter, and the sheath may optionally include at least one sheath, and the number of the sheaths is not limited. For example, there are a first sheath and a second sheath, the second sheath is sleeved outside the first sheath, the fixing and locking structure is sleeved outside the second sheath, and so on.

In particular, the drive shaft 6 is a mechanical transmission structure, preferably extending through the entire conduit. Drive shaft 6 may alternatively consist of or comprise a flexible cable, which may alternatively consist of layers of fibres in different orientations. The drive shaft 6 may alternatively consist of a plurality of coaxial windings, the proximal end of the drive shaft 6 being connected to an extracorporeal drive device 8, the drive shaft 6 being arranged to transmit torque from the extracorporeal drive device 8 to a pump device 7 at the distal end of the drive shaft 6.

The pump device 7 is inserted into the heart or a blood vessel via a catheter and may be used to pump blood through the circulatory system. Such as in the heart, can reduce the workload on the patient's heart, for example, enabling the heart to recover after a heart attack. The pump device 7 typically comprises an impeller arranged in a pump housing, which may be arranged in a fixed diameter, or expandable, configuration. The extracorporeal drive 8 may be an electric motor or a pneumatic motor. In the fixing and locking structure of the embodiment of the invention, the sheath tube 4 of the catheter is deformed outwards at the groove opening, so that the minimum inner diameter of the sheath tube 4 of the catheter after the chuck 2 is compressed, locked and fixed can be estimated through the following calculation formula:

D=d-d×n×(arcsin(w/d))/π-2δ，

wherein, D: the inner diameter of the sheath tube 4 after the chuck 2 is compressed; d: the chuck 2 has a pre-compression inner diameter; n: the number of the notches; w: the width of the notch; δ: the sheath 4 is thick. From this can calculate the minimum internal diameter after sheath pipe 4 compression locking is fixed through setting for notch number and notch width, guarantee sheath pipe 4 internal dimension.

In order to make the positive stress of the fixing and locking structure to the sheath tube 4 uniform, the groove width and the number of notches, i.e., the cumulative width of the plurality of notches, should be reduced as much as possible. Under the condition of certain notch accumulated width, the number of the notches is increased to reduce the width of the notch, so that the sheath tube 4 is deformed more uniformly. However, the interventional catheter instrument generally has a small outer diameter, and is provided with excessive notches, so that the processing difficulty and cost are increased. While the cumulative width of the notches should be determined to be the minimum value based on the amount of deformation of the material of the sheath 4 corresponding to the required maximum static friction force.

In the prior art, when the sheath tube 4 is made of a very soft material, the locking ring 5 is difficult to achieve the required maximum static friction force by reducing the limited size. And the chuck 2 can apply positive stress to the sheath 4 through notch shrinkage, and the required maximum static friction force can be obtained through the reduction of the small size.

In the fixed locking structure, the number of the notches of the clamping part at one end of the chuck 2 can be set to be 2-16, and the notches are uniformly distributed. When the sheath 4 is small, for example, less than 9fr, the number of the notches should be reduced to prevent the stress concentration, and 2 to 8 are preferable, because the contact area between the chuck 2 and the sheath 4 is small. Wherein the 9fr sheath tube 4 has a corresponding slot width of 0.78mm (2 slots) to 0.18mm (8 slots). When the size of the sheath tube 4 is 4fr-11fr, the number of the notches of the chuck 2 is 2 to 12, and when the size of the sheath tube 4 is extremely large, the number of the notches can be properly increased according to the actual situation so as to avoid the concentration of deformation positions and the occurrence of unexpected deformation.

Referring to fig. 3-7, in the fixing and locking structure according to the embodiment of the present invention, the connection structure between the inner cylinder 1 and the outer cylinder 3 is a threaded connection structure, the threaded connection structure includes an external thread 12 disposed on the outer wall of the proximal end of the inner cylinder 1 and an internal thread 33 disposed on the inner wall of the distal end of the outer cylinder 3, the external thread 12 is matched with the internal thread 33, when the proximal end of the inner cylinder 1 is gradually screwed into the distal end of the outer cylinder 3, the press-fastening portion gradually presses the clamping portion to contract inward, and the sheath tube 4 of the catheter deforms outward at the notch.

Referring to fig. 8 and 9, in the fixing and locking structure according to the embodiment of the present invention, the connection structure between the inner cylinder 1 and the outer cylinder 3 is a snap connection structure, the snap connection structure includes a positioning pin 13 disposed on the outer wall of the proximal end of the inner cylinder 1 and a ring groove 34 disposed on the inner wall of the distal end of the outer cylinder 3, the ring groove 34 is circumferentially disposed along the inner wall of the outer cylinder 3, the ring groove 34 is at least one, a guide groove 35 is axially disposed on the inner wall of the distal end of the outer cylinder 3, the guide groove 35 is communicated with the ring groove 34, the positioning pin 13 axially slides into the ring groove 34 through the guide groove 35 to be rotatably locked into the ring groove 34 for fixation, when the inner cylinder 1 is locked into the ring groove 34 of the outer cylinder 3 through the positioning pin 13, the press-clamping portion presses the clamping portion to contract inwards, and the sheath tube 4 of the catheter deforms outwards at the notch.

Preferably, the outer walls of the outer barrel 3 and the inner barrel 1 are provided with anti-slip lines, so that the outer barrel is convenient to hold and lock.

When the fixing and locking structure is used in a percutaneous interventional blood pump, the inner cylinder body 1 is connected with a suture system, and the outer cylinder body 3 is connected with a bacteria-blocking sleeve structure. In the actual operation process, the relative position of the suture system on the sheath 4 is different for different patients, and the suture system can move freely on the sheath 4. In the initial state, the inner cylinder 1 and the outer cylinder 3 are in an unconnected state, and after the suture system reaches a designated position along with the inner cylinder 1, the suture system is connected to the outer cylinder 3. The connection of interior barrel 1 and outer barrel 3 for the sewing system with hinder the bacterial cover structure fastening, when interior barrel 1 and outer barrel 3 are connected, crimping portion extrusion chuck 2's card-tight part simultaneously. The clamping part of the chuck 2 is shrunk inwards to be fixed on the sheath tube 4 through the notch, so that the sewing system is fixed; sheath pipe 4 is along the even deformation of notch outside, avoids the excessive deformation of sheath pipe 4.

Referring to fig. 10, the medical catheter according to the embodiment of the present invention includes a driving shaft 6 and a sheath 4 located outside the driving shaft 6, and a fixing and locking structure for fixing the sheath 4 is disposed outside the sheath 4.

Referring to fig. 11, the embodiment of the present invention includes a pump device 7, a catheter and an extracorporeal drive device 8, the catheter includes a drive shaft 6 and a sheath 4 located outside the drive shaft 6, the extracorporeal drive device 8 drives the pump device 7 through the drive shaft 6, and a fixing and locking structure for fixing the sheath 4 is provided outside the sheath 4.

In summary, the fixing and locking structure, the medical catheter and the blood pump according to the embodiment of the present invention are provided with the chuck 2 having the clamping part, and the sheath 4 of the catheter is fixedly locked by pressing the clamping part through the pressing part between the inner cylinder 1 and the outer cylinder 3; the clamping part is uniformly provided with notches along the circumferential direction, so that the sheath tube 4 deforms outwards at the notches, the deformation amount of the sheath tube 4 is controllable, and the minimum inner diameter of the deformed sheath tube 4 can be estimated; the clamping part and the crimping part are of a circular truncated cone structure and are abutted through a circular truncated cone surface, so that radial pressure can be applied to the clamping part during axial locking, sufficient static friction is generated, and a fixed locking effect is guaranteed.

Although the present invention has been described with respect to the preferred embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.