CN218900444U - Safety indwelling needle with backflow prevention function - Google Patents

Abstract

The utility model belongs to the field of medical equipment, and relates to a safety type indwelling needle with a backflow prevention function, which comprises a catheter seat assembly, a spring plate seat assembly and a needle seat assembly, wherein one end of the spring plate seat assembly is inserted into the catheter seat assembly, and the other end of the spring plate seat assembly is inserted into the needle seat assembly; the needle seat assembly comprises a needle seat and a needle tube, and the rear end of the needle tube is fixedly connected with the needle seat; the catheter seat component comprises a catheter seat, the front end of the catheter seat is connected with a catheter, and an anti-backflow valve and a valve switch which is matched with the anti-backflow valve to work are fixed in the inner cavity of the catheter seat; the spring plate seat assembly comprises a spring plate seat, a spring card is arranged in the spring plate seat, the tail end of the spring card is fixed with the tail part of the spring plate seat, and the head end of the spring card is provided with a front end hook body; the needle tube penetrates through the elastic sheet seat, the backflow prevention valve and the valve switch which are inserted into the guide tube seat penetrate out of the guide tube, and the front end hook body of the spring card is positioned on one side of the needle tube. The utility model can not only prevent blood from overflowing, but also avoid the situation that other people are injured by the needle after the needle is pulled out.

Description

Safety indwelling needle with backflow prevention function

Technical Field

The utility model relates to a safety indwelling needle with a backflow prevention function, and belongs to the field of medical devices.

Background

The venous indwelling needle is a medical instrument for clinical venous transfusion treatment, when in use, the catheter and the needle tube are punctured together into a blood vessel, and after the catheter completely enters the blood vessel, the needle tube is withdrawn, and only the soft catheter is indwelled in the blood vessel, so that transfusion treatment is carried out. The use of the indwelling needle can greatly reduce the infusion and needle insertion times, comprehensively lighten the pain of infusion patients and reduce the working intensity of medical staff, and is acceptable to both doctors and patients.

However, compared with the closed type indwelling needle, the structure of the straight type indwelling needle is easy to cause blood overflow, so that the application and popularization degree of the straight type indwelling needle are low. When the straight indwelling needle is successfully punctured and exits the needle tube, medical staff needs to press the upper part of the skin of the blood vessel where the catheter is positioned to seal the blood vessel so as to reduce the blood outflow. However, this mode of operation requires close fitting of the hands, and is prone to sealing failure, blood spilling, blood contamination, and patient panic. In addition, needle stick injuries have become an important occupational injury for clinical medical staff, and the major hazard of needle stick injuries is the occurrence of blood-borne infectious diseases, so that the protection of nursing staff against blood-borne infectious diseases is more urgent. Therefore, developing a safety indwelling needle with an anti-reflux function is a problem to be solved by those skilled in the art.

Disclosure of Invention

The utility model aims to solve the technical problems that: the safety type indwelling needle with the anti-reflux function can prevent blood from overflowing and avoid other personnel from being injured by needle punching after needle withdrawal.

The utility model relates to a safety indwelling needle with a backflow prevention function, which comprises a catheter seat assembly, a spring plate seat assembly and a needle seat assembly, wherein one end of the spring plate seat assembly is inserted into the catheter seat assembly, and the other end of the spring plate seat assembly is inserted into the needle seat assembly; the needle seat assembly comprises a needle seat and a needle tube, and the rear end of the needle tube is fixedly connected with the needle seat; the catheter seat component comprises a catheter seat, the front end of the catheter seat is connected with a catheter, and an anti-backflow valve and a valve switch which is matched with the anti-backflow valve to work are fixed in the inner cavity of the catheter seat; the spring plate seat assembly comprises a spring plate seat, a spring card is arranged in the spring plate seat, the tail end of the spring card is fixed with the tail part of the spring plate seat, and the head end of the spring card is provided with a front end hook body; the needle tube penetrates through the elastic sheet seat, the backflow prevention valve and the valve switch which are inserted into the guide tube seat penetrate out of the guide tube, and the front end hook body of the spring card is positioned on one side of the needle tube.

The front end of the spring plate seat is inserted into the tail end of the catheter seat, and the rear end of the spring plate seat is positioned in the inner cavity of the needle seat; in the initial state, the front end hook body of the spring card is jacked up by the needle tube and positioned at one side of the needle tube, at the moment, the front end hook body of the spring card presses the needle tube under the action of elastic force, and at the moment, the needle tube penetrates through the anti-reflux valve, the anti-reflux valve tightly wraps the needle tube, meanwhile, the catheter seat is clamped at the shaft shoulder position of the head end of the needle seat, and the catheter seat component, the elastic sheet seat component and the needle seat component cannot be separated under the action of no external force; when the needle holder is used, the needle holder is held to drive the needle tube to puncture, meanwhile, the needle holder pushes the catheter at the front end of the catheter holder to puncture together with the needle tube, after the puncture is completed, the needle is withdrawn, in the process of withdrawing the needle tube, when the head of the needle tube retreats to the rear of the front end hook body of the spring card, the needle tube does not have supporting force on the front end hook body any more, so the front end hook body of the spring card falls back under the action of elasticity, at the moment, the needle point of the needle tube is covered and blocked by the front end hook body, and when the needle holder is dragged backwards, the spring sheet seat is separated from the catheter holder immediately; after the needle tube is withdrawn from the anti-reflux valve, the anti-reflux valve is automatically closed, so that the blood is effectively prevented from overflowing; when transfusion is needed, the outer luer conical connector of the transfusion device is inserted into the catheter seat, and when the transfusion device is pushed forwards, the transfusion device pushes the valve switch to move forwards, so that the through incision of the anti-reflux valve is opened, and transfusion treatment is realized; after one infusion treatment, the catheter sealing liquid is injected into the catheter seat assembly to prevent blood outflow. After withdrawing the needle, the needle point is covered and blocked by the front end hook body, so that the condition that other people are injured by the needle after the needle is pulled out can be effectively avoided, and the safety is high.

Preferably, the anti-backflow valve comprises a valve body, wherein the front end of the valve body is provided with a through cut, and the rear end of the valve body is provided with a valve cavity; the valve switch comprises a switch body, wherein the switch body is provided with a hollow circulation cavity, and the front end of the switch body is inserted into the valve cavity. The periphery of the valve body is in a ladder shape, the big head end of the front end of the valve body is fixedly mounted with the inner cavity wall of the corresponding position of the guide pipe seat in an interference fit manner, the inner cavity wall of the guide pipe seat behind the big head end of the front end of the valve body is additionally provided with a back-off, the back-off is clamped at the Zhou Zhoujian position outside the valve body, the front part of the big head end of the front end of the valve body is clamped at the shaft shoulder of the inner cavity wall of the guide pipe seat, and the valve body is clamped, so that the position of the valve body is effectively prevented from moving randomly.

Preferably, the through incision is Y-shaped, and after the needle tube is pulled out, the Y-shaped through incision is automatically closed under the elastic action to prevent blood from flowing out.

Preferably, the front end of the switch body is conical, and the periphery of the front end of the switch body is provided with a barb. The valve body rear end is equipped with the binding off hole, and binding off hole diameter is less than valve cavity diameter and barb diameter, guarantees that the needle tubing in-process pulls out the in-process, and valve switch barb is in the valve that prevents against the current all the time.

Preferably, the rear end of the inner cavity of the spring plate seat is provided with a spring plate fixing seat, a seat hole is arranged in the middle of the spring plate fixing seat, and a fixing groove is formed between the spring plate fixing seat and the spring plate seat rear end plate; the tail part of the spring card is provided with an inverted U-shaped groove, the front end hook body is arranged at the front end of the inverted U-shaped groove, the rear end of the inverted U-shaped groove is provided with an elastic folding hook, the inverted U-shaped groove is clamped on the elastic sheet fixing seat, and the elastic folding hook is positioned in the fixing groove; the needle tube penetrates through the rear end plate of the elastic sheet seat, a rear limit hole and a seat hole of the groove wall at one side of the inverted U-shaped groove of the spring card and a front limit hole arranged at the front end of the elastic sheet seat, and the elastic folding hook and the front end hook body are respectively arranged at the opposite side of the needle tube; the front end of the needle tube is provided with an indentation, and the diameter of the indentation of the needle tube is larger than the diameter of the rear limit hole. The seat hole is overlapped with the rear limit hole; the reinforcing ribs are additionally arranged on the front arm of the spring card, so that the strength of the front arm of the spring card is increased, the elastic effect is improved, the front hook body can rebound rapidly, and the needling prevention effect is enhanced; the spring card is original non-deformation state when not receiving the needle tubing power, spring card forearm and reverse U type groove opening part parallel and level this moment, be deformation state when receiving the power of needle tubing jack-up, consequently, back is withdrawn at the needle tubing, spring card's front end coupler body kick-backs rapidly and stop needle tubing needle tip, and needle tubing front end is equipped with the indentation and moves to back spacing hole department just this moment, because needle tubing indentation department diameter is greater than back spacing hole diameter, consequently drive shell fragment seat and pipe seat separation simultaneously at the in-process that operation needle file drove the needle tubing and continue the back.

Preferably, a fixed hook is additionally arranged on the inner cavity of the spring plate seat at one side of the spring plate fixing seat close to the front end hook body, and the spring card is clamped below the fixed hook. After the needle tube jacks up the front end hook body to deform the spring card, the fixed hook presses the position of the spring card close to the inverted U-shaped groove, so that the spring card is prevented from being lifted up entirely, the deformation effect is influenced, and the rebound effect is influenced.

Preferably, the outer wall of the middle part of the elastic sheet seat is additionally provided with a guide column, both sides of the inner cavity wall of the needle seat are provided with guide sliding grooves, the guide column is inserted into the guide sliding grooves, and the guide column is in sliding fit with the guide sliding grooves. When the needle tube is installed, the guide post is matched with the guide sliding groove, so that the spring plate seat and the needle seat are smooth when being installed and matched, and the spring plate seat and the needle seat can be prevented from rotating relatively in the process of controlling the needle tube to withdraw by the hand-held needle seat, and the spring card can be guaranteed to play a better role in protection.

Preferably, the top end of the spring plate seat corresponding to the spring card on one side of the front end hook body is hollow, a rear end groove is additionally formed in the rear end of the inner cavity of the catheter seat, and the front end hook body jacked by the needle tube is clamped in the rear end groove. The front-end hook body is clamped in the rear-end groove to a certain extent, so that the guide tube seat and the elastic sheet seat are fixed, and when the front-end hook body rebounds to leave the rear-end groove, the guide tube seat and the elastic sheet seat can be easily separated.

Preferably, the front end of the elastic sheet seat matched with the inner cavity of the catheter seat is a luer conical connector, and the luer conical connector is matched with the inner cavity of the catheter seat to effectively prevent the elastic sheet seat from shaking.

Preferably, the periphery of the rear part of the switch body is provided with a convex supporting ring, the outer diameter of the convex supporting ring is matched with the inner diameter of the inner cavity wall at the corresponding position of the catheter seat, and the valve switch is effectively prevented from shaking in the catheter seat. The shell fragment seat front end sets up dodges the hole, dodges the setting in hole and makes the rear end of the switch body and shell fragment seat can not take place the lower on the basis of mutual influence guarantee overall dimension, and dodges the setting in hole and also can avoid valve switch to rock in the pipe seat to a certain extent.

Compared with the prior art, the utility model has the following beneficial effects:

the utility model has reasonable structural design, and the arrangement of the anti-reflux valve can realize the prevention of the overflow of blood; the arrangement of the elastic sheet seat assembly and the cooperation of the elastic sheet seat assembly and the catheter seat assembly as well as the needle seat assembly effectively avoid the condition that other personnel are injured by the needle after the needle is pulled out.

Drawings

FIG. 1 is a schematic view of a safety indwelling needle with anti-reflux function;

FIG. 2 is a schematic view of a catheter hub assembly;

FIG. 3 is an enlarged view of part of A in FIG. 2;

FIG. 4 is a top view of the spring plate seat assembly;

FIG. 5 is a perspective view of the spring plate seat assembly;

fig. 6 is a schematic view of the needle hub assembly;

fig. 7 is a schematic view of the catheter hub assembly, the spring hub assembly and the hub assembly mated (initial state);

fig. 8 is a schematic view of the catheter hub assembly, the spring hub assembly and the hub assembly mated (post-needle withdrawal state);

FIG. 9 is a schematic diagram of an anti-reflux valve structure;

FIG. 10 is a schematic diagram of the valve and valve switch engagement (infusion state) for anti-reflux;

fig. 11 is a sectional view showing the cooperation of the valve for preventing reverse flow and the valve switch (state at the time of infusion).

In the figure: 1. a catheter hub assembly; 2. a spring plate seat assembly; 3. a hub assembly;

11. a conduit; 12. a catheter holder; 13. an anti-reflux valve; 14. a valve switch;

121. reversing; 122. a rear end slot; 131. a through incision; 132. a valve cavity; 133. a valve body; 141. a raised support ring; 142. a switch body; 143. a hollow flow-through chamber; 144. a barb;

21. a spring plate seat; 22. a spring card;

211. a fixed hook; 212. a fixing groove; 213. a spring plate fixing seat; 214. a front limit hole; 215. a guide post; 216. a seat hole; 217. avoidance holes;

221. a front end hook body; 222. reinforcing ribs; 223. spring-shaped folding hooks; 224. an inverted U-shaped groove; 225. a rear limit hole; 31. a needle tube; 32. a needle stand; 311. indentation; 321. and a guiding chute.

Detailed Description

The utility model is further described below with reference to the accompanying drawings:

1-11, the safety indwelling needle with the backflow prevention function comprises a catheter seat assembly 1, a spring plate seat assembly 2 and a needle seat assembly 3, wherein one end of the spring plate seat assembly 2 is inserted into the catheter seat assembly 1, and the other end of the spring plate seat assembly 2 is inserted into the needle seat assembly 3; the needle seat assembly 3 comprises a needle seat 32 and a needle tube 31, and the rear end of the needle tube 31 is fixedly connected with the needle seat 32; the catheter seat assembly 1 comprises a catheter seat 12, a catheter 11 is connected to the front end of the catheter seat 12, and an anti-backflow valve 13 and a valve switch 14 which is matched with the anti-backflow valve 13 are fixed in the inner cavity of the catheter seat 12; the spring plate seat assembly 2 comprises a spring plate seat 21, a spring card 22 is arranged in the spring plate seat 21, the tail end of the spring card 22 is fixed with the tail of the spring plate seat 21, and the head end of the spring card 22 is provided with a front end hook 221; the needle tube 31 penetrates through the spring plate seat 21, the backflow prevention valve 13 and the valve switch 14 which are inserted into the catheter seat 12 penetrate out of the catheter 11, and the front end hook 221 of the spring card 22 is positioned on one side of the needle tube 31.

In this embodiment:

the anti-backflow valve 13 comprises a valve body 133, a through notch 131 is formed in the front end of the valve body 133, and a valve cavity 132 is formed in the rear end of the valve body 133; the valve switch 14 includes a switch body 142, the switch body 142 having a hollow flow chamber 143, the front end of the switch body 142 being inserted into the valve cavity 132. The periphery of the valve body 133 is in a step shape, the big head end of the front end of the valve body 133 is fixedly mounted with the inner cavity wall of the corresponding position of the catheter seat 12 in an interference fit manner, the back-off 121 is additionally arranged on the inner cavity wall of the catheter seat 12 behind the big head end of the front end of the valve body 133, the back-off 121 is clamped at the Zhou Zhoujian position outside the valve body 133, the front part of the big head end of the valve body 133 is clamped at the shaft shoulder of the inner cavity wall of the catheter seat 12, and the valve body 133 is clamped, so that the position of the valve body 133 is effectively prevented from moving randomly. The through-cut 131 is Y-shaped, and after the needle tube 31 is withdrawn, the Y-shaped through-cut 131 is automatically closed under the elastic action to prevent blood from flowing out.

The front end of the switch body 142 is tapered, and the outer periphery of the front end of the switch body 142 is provided with a barb 144. The rear end of the valve body 133 is provided with a closing hole, the diameter of which is smaller than the diameter of the valve cavity 132 and the diameter of the barb 144, so that the barb 144 of the valve switch 14 is always positioned in the anti-reflux valve 13 in the process of pulling out the needle tube 31.

The rear end of the inner cavity of the spring plate seat 21 is provided with a spring plate fixing seat 213, a seat hole 216 is arranged in the middle of the spring plate fixing seat 213, and a fixing groove 212 is arranged between the spring plate fixing seat 213 and the rear end plate of the spring plate seat 21; the tail of the spring card 22 is provided with an inverted U-shaped groove 224, a front end hook 221 is arranged at the front end of the inverted U-shaped groove 224, the rear end of the inverted U-shaped groove 224 is provided with a spring-shaped folding hook 223, the inverted U-shaped groove 224 is clamped on the spring plate fixing seat 213, and the spring-shaped folding hook 223 is positioned in the fixing groove 212; the needle tube 31 penetrates through the rear end plate of the spring plate seat 21, a rear limit hole 225 at one side of the inverted U-shaped groove 224 of the spring card 22, a seat hole 216 and a front limit hole 214 arranged at the front end of the spring plate seat 21, and a spring-shaped folding hook 223 and a front end hook 221 are respectively arranged at the opposite side of the needle tube 31; the front end of the needle tube 31 is provided with an indentation 311, and the diameter of the indentation 311 of the needle tube 31 is larger than the diameter of the rear limit hole 225. The seat hole 216 coincides with the rear limit hole 225; the reinforcing ribs 222 are additionally arranged on the front arm of the spring card 22, so that the strength of the front arm of the spring card 22 is increased, the elastic effect is improved, the front end hook 221 can rebound rapidly, and the needling prevention effect is enhanced; the spring card 22 is in an original non-deformation state when not subjected to the force of the needle tube 31, at the moment, the front arm of the spring card 22 is flush with the opening of the inverted U-shaped groove 224, and is in a deformation state when subjected to the jacking force of the needle tube 31, so that after the needle tube 31 is withdrawn, the front end hook 221 of the spring card 22 quickly rebounds to block the needle tip of the needle tube 31, at the moment, the front end of the needle tube 31 is provided with an indentation 311 to move to the position of the rear limit hole 225 just, and because the diameter of the indentation 311 of the needle tube 31 is larger than the diameter of the rear limit hole 225, the spring plate seat 21 is driven to be separated from the catheter seat 12 simultaneously in the process of operating the needle seat 32 to drive the needle tube 31 to continuously withdraw.

A fixed hook 211 is additionally arranged on the inner cavity of the spring plate seat 21 at one side of the spring plate fixing seat 213 close to the front end hook 221, and the spring card 22 is clamped below the fixed hook 211. After the front end hook body 221 is jacked up by the needle tube 31 to deform the spring card 22, the fixing hook 211 presses the position of the spring card 22 close to the inverted U-shaped groove 224, so that the spring card 22 is prevented from being lifted up completely, the deformation effect is influenced, and the rebound effect is further influenced.

The outer wall of the middle part of the spring plate seat 21 is additionally provided with a guide post 215, both sides of the inner cavity wall of the needle seat 32 are provided with guide slide grooves 321, the guide post 215 is inserted into the guide slide grooves 321, and the guide post 215 is in sliding fit with the guide slide grooves 321. During installation, the guide post 215 is matched with the guide chute 321, so that the elastic sheet seat 21 and the needle seat 32 are smooth during installation and matching, and the relative rotation between the elastic sheet seat 21 and the needle seat 32 can be prevented in the process of controlling the needle tube 31 to withdraw by holding the needle seat 32, so that the spring card 22 can be well protected.

The top end of the spring plate seat 21 corresponding to the spring card 22 on one side of the front end hook 221 is hollow, the rear end of the inner cavity of the catheter seat 12 is additionally provided with a rear end groove 122, and the front end hook 221 jacked up by the needle tube 31 is clamped in the rear end groove 122. The front hook 221 is clamped in the rear slot 122 to fix the catheter seat 12 and the spring plate seat 21 to a certain extent, and when the front hook 221 rebounds from the rear slot 122, the catheter seat 12 and the spring plate seat 21 can be easily separated.

The front end of the elastic sheet seat 21 matched with the inner cavity of the catheter seat 12 is a luer conical connector, and the luer conical connector is matched with the inner cavity of the catheter seat 12, so that the elastic sheet seat 21 is effectively prevented from shaking.

The periphery at the rear part of the switch body 142 is provided with a convex supporting ring 141, and the outer diameter of the convex supporting ring 141 is matched with the inner diameter of the inner cavity wall at the corresponding position of the catheter seat 12, so that the valve switch 14 is effectively prevented from shaking in the catheter seat 12. The front end of the spring plate seat 21 is provided with the avoiding hole 217, the back end of the switch body 142 and the spring plate seat 21 cannot be mutually influenced by each other due to the arrangement of the avoiding hole 217, the overall size is ensured to be smaller, and the valve switch 14 can be prevented from shaking in the catheter seat 12 to a certain extent due to the arrangement of the avoiding hole 217.

The front end of the spring plate seat 21 is inserted into the tail end of the catheter seat 12, and the rear end of the spring plate seat 21 is positioned in the inner cavity of the needle seat 32; in the initial state, the front end hook 221 of the spring card 22 is jacked up by the needle tube 31 to be positioned at one side of the needle tube 31, at the moment, the front end hook 221 of the spring card 22 presses the needle tube 31 under the action of elastic force, and at the moment, the needle tube 31 penetrates through the anti-reflux valve 13, the anti-reflux valve 13 tightly wraps the needle tube 31, meanwhile, the catheter seat 12 is clamped at the shaft shoulder position of the head end of the needle seat 32, and the catheter seat component 1, the elastic sheet seat component 2 and the needle seat component 3 cannot be separated under the action of no external force; when the needle holder 32 is used specifically, the needle tube 31 is driven to puncture by the hand-held needle holder 32, meanwhile, the needle holder 32 pushes the catheter 11 at the front end of the catheter holder 12 to puncture together with the needle tube 31, after the puncture is completed, the needle is withdrawn, in the process of withdrawing the needle tube 31, when the head of the needle tube 31 retreats to the rear of the front end hook 221 of the spring card 22, the needle tube 31 does not have supporting force on the front end hook 221 any more, so that the front end hook 221 of the spring card 22 falls back under the action of elasticity, at the moment, the needle point of the needle tube 31 is blocked by the front end hook 221, and when the needle holder 32 is dragged backwards again, the indentation 311 of the needle tube 31 drives the elastic sheet seat 21 to withdraw, and the elastic sheet seat 21 is separated from the catheter holder 12 immediately; after the needle tube 31 is withdrawn from the anti-reflux valve 13, the anti-reflux valve 13 is automatically closed, so that the blood is effectively prevented from overflowing; when infusion is needed, the outer luer conical connector of the infusion apparatus is inserted into the catheter seat 12, and when the infusion apparatus is pushed forward, the infusion apparatus pushes the valve switch 14 to move forward, so that the through-cut 131 of the anti-reflux valve 13 is opened, and infusion treatment is realized; after one infusion treatment, the catheter sealing liquid is injected into the catheter seat assembly 1, and a dry plastic cap is buckled at the tail end of the catheter seat 12 to prevent blood outflow. After withdrawing the needle, the needle tip is blocked by the front end hook 221, so that the condition that other people are injured by the needle after the needle is pulled out can be effectively avoided, and the safety is high.

Claims (10)

1. The utility model provides a safe type of area prevents flowing back function keeps somewhere needle which characterized in that: comprises a catheter seat assembly (1), a spring plate seat assembly (2) and a needle seat assembly (3), wherein one end of the spring plate seat assembly (2) is inserted into the catheter seat assembly (1), and the other end is inserted into the needle seat assembly (3); the needle seat assembly (3) comprises a needle seat (32) and a needle tube (31), and the rear end of the needle tube (31) is fixedly connected with the needle seat (32); the catheter seat assembly (1) comprises a catheter seat (12), the front end of the catheter seat (12) is connected with a catheter (11), and an anti-reflux valve (13) and a valve switch (14) which is matched with the anti-reflux valve (13) are fixed in the inner cavity of the catheter seat (12); the spring plate seat assembly (2) comprises a spring plate seat (21), a spring card (22) is arranged in the spring plate seat (21), the tail end of the spring card (22) is fixed with the tail end of the spring plate seat (21), and the head end of the spring card is provided with a front end hook body (221); the needle tube (31) penetrates through the elastic sheet seat (21), the backflow prevention valve (13) and the valve switch (14) which are inserted into the catheter seat (12) penetrate out of the catheter (11), and the front end hook body (221) of the spring card (22) is positioned on one side of the needle tube (31).

2. The safety indwelling needle with anti-reflux function according to claim 1, wherein: the anti-backflow valve (13) comprises a valve body (133), a through cut (131) is arranged at the front end of the valve body (133), and a valve cavity (132) is arranged at the rear end of the valve body (133); the valve switch (14) comprises a switch body (142), the switch body (142) is provided with a hollow circulation cavity (143), and the front end of the switch body (142) is inserted into the valve cavity (132).

3. The safety indwelling needle with anti-reflux function according to claim 2, wherein: the through-cut (131) is Y-shaped.

4. The safety indwelling needle with anti-reflux function according to claim 2 or 3, wherein: the front end of the switch body (142) is conical, and a barb (144) is arranged on the periphery of the front end of the switch body (142).

5. The safety indwelling needle with anti-reflux function according to claim 1, wherein: the rear end of the inner cavity of the spring plate seat (21) is provided with a spring plate fixing seat (213), the middle part of the spring plate fixing seat (213) is provided with a seat hole (216), and a fixing groove (212) is arranged between the spring plate fixing seat (213) and the rear end plate of the spring plate seat (21); the tail of the spring card (22) is provided with an inverted U-shaped groove (224), a front end hook body (221) is arranged at the front end of the inverted U-shaped groove (224), the rear end of the inverted U-shaped groove (224) is provided with a spring-shaped folding hook (223), the inverted U-shaped groove (224) is clamped on the spring sheet fixing seat (213), and the spring-shaped folding hook (223) is positioned in the fixing groove (212); the needle tube (31) penetrates through the rear end plate of the elastic sheet seat (21), a rear limit hole (225) of the groove wall at one side of the inverted U-shaped groove (224) of the spring card (22), a seat hole (216) and a front limit hole (214) arranged at the front end of the elastic sheet seat (21), and the elastic folding hook (223) and the front end hook body (221) are respectively arranged at the opposite side of the needle tube (31); the front end of the needle tube (31) is provided with an indentation (311), and the diameter of the indentation (311) of the needle tube (31) is larger than the diameter of the rear limit hole (225).

6. The safety indwelling needle with anti-reflux function according to claim 5, wherein: a fixed hook (211) is additionally arranged on the inner cavity of the spring plate seat (21) at one side of the spring plate fixing seat (213) close to the front end hook body (221), and the spring card (22) is clamped below the fixed hook (211).

7. The safety indwelling needle with anti-reflux function according to claim 1 or 5, wherein: the outer wall of the middle part of the spring plate seat (21) is additionally provided with a guide post (215), both sides of the inner cavity wall of the needle seat (32) are provided with guide sliding grooves (321), the guide post (215) is inserted into the guide sliding grooves (321), and the guide post (215) is in sliding fit with the guide sliding grooves (321).

8. The safety indwelling needle with anti-reflux function according to claim 1 or 5, wherein: the top end of the spring plate seat (21) corresponding to the spring card (22) at one side of the front end hook body (221) is hollow, the rear end of the inner cavity of the catheter seat (12) is additionally provided with a rear end groove (122), and the front end hook body (221) jacked by the needle tube (31) is clamped in the rear end groove (122).

9. The safety indwelling needle with anti-reflux function according to claim 1 or 5, wherein: the front end of the elastic sheet seat (21) matched with the inner cavity of the catheter seat (12) is a luer cone joint which is matched with the inner cavity of the catheter seat (12).

10. The safety indwelling needle with anti-reflux function according to claim 2, wherein: the periphery of the rear part of the switch body (142) is provided with a convex supporting ring (141), and the outer diameter of the convex supporting ring (141) is matched with the inner diameter of the inner cavity wall at the corresponding position of the catheter seat (12).

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