Handheld needleless injection instrument and use method thereof

Abstract

The invention provides a handheld needleless injection instrument and a using method thereof, and belongs to the technical field of needleless injectors. The handheld needleless injection instrument comprises an injection shell; the injection cylinder is arranged in the injection shell; the connector is fixedly connected to the lower end of the syringe; the replaceable needle head is connected to the outer surface of the connector in a sliding manner; the number of the replacing assemblies is two, each replacing assembly comprises a fixing groove, an extrusion plate, a first spring groove, a first spring, a fixing block, a pressing groove and a liquid outlet hole, the pressing groove is formed in one side end of the replacing needle head, the fixing groove is formed in the inner wall of one side of the pressing groove, and the replacing needle head can be used as a disposable needle head to guarantee cleanliness of the replacing needle head; during injection, the replaceable needle heads of different liquid outlet holes can be replaced to cooperate with injection according to specific use conditions.

Description

Technical Field

[0001] This invention belongs to the field of needle-free injector technology, specifically relating to a handheld needle-free injection device and its usage method. Background Technology

[0002] Needle-free injection, also known as jet injection, is a medical device that uses the instantaneous high pressure generated by a power source to force the drug (liquid or lyophilized powder) in the syringe through the nozzle to form a high-speed, high-pressure jet (the flow rate is generally greater than 100m / s), thereby allowing the drug to penetrate the outer layer of the skin and release its effects into the subcutaneous, intradermal, and other tissue layers.

[0003] A search revealed a needle-free injector disclosed in Chinese Patent Publication No. CN115337503B, comprising a drug storage assembly, an injection assembly, a safety device, and an actuation assembly. The drug storage assembly includes a drug storage chamber housing, which encloses a drug storage cavity pre-filled with liquid medication. The injection assembly includes an injection cavity housing and a piston assembly, with an injection micro-orifice at the front end of the injection cavity housing. The piston assembly is movably disposed within the injection cavity. The safety device is operably disposed between the drug storage cavity and the injection cavity, and is configured to enable communication between the drug storage cavity and the injection cavity when actuated. The actuation assembly includes an operating device configured to move towards the injection micro-orifice after the safety device is actuated, allowing the liquid medication in the drug storage cavity to reach the injection cavity, and to trigger the piston assembly to move when it reaches a predetermined position, causing the liquid medication in the injection cavity to be ejected through the injection micro-orifice. The needle-free injector according to the above scheme can accelerate injection speed and improve injection efficiency.

[0004] The needleless injector described above is equipped with a drug storage chamber to store the medication to be injected. Therefore, users do not need to draw the medication from other storage bottles. However, different types of needles need to be changed depending on the condition of the illness or the patient's skin condition. In the above invention and the prior art, the needles are generally fixed and need to be disinfected and cleaned after use, which is not convenient for continuous injection. Summary of the Invention

[0005] The purpose of this invention is to provide a handheld needleless injection device and its usage method, which aims to solve the problem in the prior art where different types of needles need to be changed for different diseases or patients' skin conditions. In the above invention and prior art, the needles are generally fixed and need to be disinfected and cleaned after use, which is inconvenient for continuous injection.

[0006] To achieve the above objectives, the present invention provides the following technical solution: 1. A handheld needle-free injection device, comprising: Injection casing; An injection cartridge, wherein the injection cartridge is disposed within an injection housing; A connector, which is fixedly connected to the lower end of the syringe; The replacement needle is slidably connected to the outer surface of the connector. The replacement assembly comprises two sets, each set including a fixing groove, a squeezing plate, a first spring groove, a first spring, a fixing block, a pressing groove, and a liquid outlet. The pressing groove is located on one side of the replacement needle, the fixing groove is located on one side of the inner wall of the pressing groove, the first spring groove is located on one side of the connector, the fixing block is slidably connected to the first spring groove and the fixing groove, the first spring is fixedly connected to one side of the inner wall of the first spring groove and one side of the fixing block, the squeezing plate is fixedly connected to the lower inner wall of the pressing groove, and the liquid outlet is located at the lower end of the replacement needle.

[0007] In a preferred embodiment of the present invention, both the replacement needle and the compression plate are made of medical-grade polypropylene material.

[0008] As a preferred embodiment of the present invention, a sealing film is fixedly connected to the inner circumferential wall of the liquid outlet.

[0009] In a preferred embodiment of the present invention, a drug solution tank is provided inside the syringe, an energy storage tank is provided on the upper inner wall of the drug solution tank, a limiting groove is provided on the upper inner wall of the energy storage tank, and a sliding groove is provided on the lower inner wall of the limiting groove, the energy storage tank, and the drug solution tank. The sliding groove is connected to the liquid outlet hole, a pressure boosting rod is slidably connected in the sliding groove, a spring push plate is fixedly connected to the circumferential surface of the pressure boosting rod, and an energy storage spring is fixedly connected to the upper end of the spring push plate and the upper inner wall of the energy storage tank.

[0010] In a preferred embodiment of the present invention, a support groove is formed on the circumferential surface of the booster rod, and two sets of fixing components are provided inside the injection cylinder. Each set of fixing components includes a second spring groove, a spring push block, a second spring, a support block, and a sliding groove. There are two second spring grooves, spring push blocks, and second springs. The two second spring grooves are formed on the inner circumferential wall of the limiting groove. The two spring push blocks are slidably connected to the two second spring grooves respectively. The two second springs are fixedly connected to one side of the spring push block and one side of the inner wall of the second spring groove respectively. The support block is fixedly connected to one side of the two spring push blocks and matches the support groove. The sliding groove is formed on the upper end of the support block.

[0011] As a preferred embodiment of the present invention, an injection block is provided at the upper end of the injection shell, and an injection spring is fixedly connected to the lower end of the injection block and the upper end of the injection shell. Two injection inserts are fixedly connected to the lower end of the injection block, and the two injection inserts are respectively matched with two sliding grooves.

[0012] As a preferred embodiment of the present invention, an observation mirror is fixedly connected to one side of the injection shell.

[0013] As a preferred embodiment of the present invention, a connecting hole is provided on one side of the syringe, an energy storage handle is rotatably connected to the upper end of the observation mirror via a rotating shaft, a lifting plate is fixedly connected to the circumferential surface of the booster rod, a lifting block is fixedly connected to the lower end of the energy storage handle, and one side of the lifting block slides on the lower end of the lifting plate.

[0014] As a preferred embodiment of the present invention, the upper and lower inner walls of the medicine tank are fixedly connected with two sets of sealing rings.

[0015] As a method of using a handheld needle-free injection device according to the present invention, the method includes the following steps: S1. Before performing needle-free injection, replace the needle with a new one. Place the new needle on the lower end of the connector. When the needle slides upward, it contacts the fixing block. The contact surface between the fixing block and the needle is inclined. The needle pushes the fixing block into the first spring groove and compresses the first spring. When the needle is completely covered outside the connector, the liquid outlet is aligned with the lower opening of the sliding groove. The previously compressed first spring rebounds and pushes the fixing block into the fixing groove to fix the needle, thus completing the installation of the needle. S2. After the needle replacement and installation are completed, the operator rotates the energy storage handle to drive the lifting block to rotate. The lifting block lifts the lifting plate and the pressure rod upward. As the pressure rod slides upward, it compresses the energy storage spring to contract. The pressure rod compresses the inclined surface on one side of the support block, pushing the support block towards the side of the second spring groove and compressing the second spring to contract. When the pressure rod moves upward until the support groove matches the sliding groove, the previously compressed second spring rebounds, pushing the support block into the support groove to fix the pressure rod and keep the energy storage spring in a contracted state. As the pressure rod slides upward, a vacuum is generated in the sliding groove until the pressure rod slides upward out of the sliding groove opened on the lower inner wall of the drug tank. The drug in the drug tank will flow into and fill the outlet hole and the sliding groove, thus completing the injection preparation. S3. After injection preparation is complete, the operator presses the injection block. At the same time, the two injection inserts at the lower end of the injection block are inserted into the two sliding grooves respectively. The inclined surfaces of the injection inserts press against the inclined surfaces of the sliding grooves, causing the two sliding grooves to slide outward into the support groove. The fixed restraint of the support groove makes contact. The previously compressed energy storage spring rebounds, pushing the spring push plate and the pressure booster rod into the sliding groove. With the high-speed rebound of the pressure booster rod, the pressure in the sliding groove is instantly increased, thereby ejecting the liquid in the outlet hole to complete the injection. After the injection is completed, the operator presses the two squeeze plates on both sides. The two squeeze plates squeeze the fixed block back into the first spring groove to release the fixation of the replacement needle. Then, the replacement needle is pulled out and replaced with a new replacement needle for the next injection.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. This solution allows for the use of disposable needles to ensure their cleanliness. During injection, different needles with different dispensing orifices can be used depending on the specific application. Furthermore, the needles can be quickly installed and removed using interchangeable components, making replacement convenient.

[0017] This device uses medical-grade polypropylene for both the needle replacement and the compression plate, which have excellent mechanical properties. When the needle is pressed against the patient's skin, it fits snugly. The material is inexpensive and disposable. The needle is replaced after each injection to ensure hygiene. Medical-grade polypropylene is also highly resilient. Pressing the compression plate deforms it and squeezes the fixing block to remove and replace the needle.

[0018] This device allows for continuous injection by pre-storing medication in a fixed assembly and medication tank, eliminating the need for replenishment after each injection and improving injection efficiency. Attached Figure Description

[0019] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0020] Figure 1 This is a first structural perspective view of the present invention; Figure 2 This is a perspective view of the second structure in this invention; Figure 3 This is an exploded cross-sectional view of the first structure in this invention; Figure 4 This is a cross-sectional view of the structure in this invention; Figure 5 This is an exploded cross-sectional view of the second structure in this invention; Figure 6 This is an exploded view of the structure in this invention; Figure 7 For the present invention Figure 3 Enlarged view of point A in the middle; Figure 8 For the present invention Figure 4 Enlarged view of point B in the middle.

[0021] In the diagram: 1. Injection casing; 2. Injection barrel; 3. Connector; 4. Replacement needle; 5. Fixing groove; 6. Squeezing plate; 7. First spring groove; 8. First spring; 9. Fixing block; 10. Pressing groove; 11. Liquid outlet; 12. Sealing membrane; 13. Sliding groove; 14. Pressure boosting rod; 17. Limiting groove; 18. Second spring groove; 19. Spring push block; 20. Second spring; 21. Support block; 22. Sliding inclined groove; 23. Support groove; 24. Injection block; 25. Injection spring; 26. Injection insert; 27. Observation mirror; 28. Connecting hole; 29. ​​Energy storage handle; 30. Lifting block; 31. Energy storage spring; 32. Lifting plate; 33. Spring push plate; 34. Energy storage groove; 35. Drug tank. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Example 1 Please see Figures 1-8 The present invention provides the following technical solutions: 1. A handheld needle-free injection device, comprising: Injection shell 1; Injector 2, which is located inside the injection housing 1; Connector 3 is fixedly connected to the lower end of syringe 2; Replace needle 4, which is slidably connected to the outer surface of connector 3; The replacement assembly consists of two sets. Each set includes a fixing groove 5, a squeezing plate 6, a first spring groove 7, a first spring 8, a fixing block 9, a pressing groove 10, and a liquid outlet 11. The pressing groove 10 is located on one side of the replacement needle 4. The fixing groove 5 is located on one side of the inner wall of the pressing groove 10. The first spring groove 7 is located on one side of the connector 3. The fixing block 9 is slidably connected to the first spring groove 7 and the fixing groove 5. The first spring 8 is fixedly connected to one side of the inner wall of the first spring groove 7 and one side of the fixing block 9. The squeezing plate 6 is fixedly connected to the lower inner wall of the pressing groove 10. The liquid outlet 11 is located at the lower end of the replacement needle 4.

[0024] In a specific embodiment of the present invention, the replacement needle 4 is a needleless injection head, which can be replaced after a medical injection. The lower end of the squeeze plate 6 is fixed to the lower inner wall of the pressing groove 10, and the squeeze plate 6 has a certain toughness and can be bent. When a new replacement needle 4 needs to be installed, the new replacement needle 4 is inserted into the lower end of the connector 3. When the replacement needle 4 slides upward, it contacts the fixing block 9. The contact surface between the fixing block 9 and the replacement needle 4 is an inclined surface. The replacement needle 4 squeezes the fixing block 9 and slides into the first spring groove 7, and squeezes the first spring 8 to retract. When the replacement needle 4 is completely sleeved outside the connector 3, the liquid outlet 11 and the lower opening of the sliding groove 13 are closed. Alignment is achieved by the first spring 8, which was previously compressed, rebounding to push the fixing block 9 into the fixing groove 5, thus securing the replacement needle 4. After one injection, the operator presses the squeezing plates 6 on both sides with their fingers, squeezing the fixing block 9 into the first spring groove 7 to release the fixation of the replacement needle 4. The replacement needle 4 is then pulled out for replacement. This device allows the replacement needle 4 to be used as a disposable needle, ensuring its cleanliness. During injection, different replacement needles with different outlet holes 11 can be used for injection depending on the specific application. The replacement needle 4 can be quickly installed and removed using the replacement assembly, making replacement convenient.

[0025] Please refer to the details. Figures 1-8 The replacement needle 4 and the compression plate 6 are both made of medical-grade polypropylene.

[0026] In this embodiment: both the replacement needle 4 and the compression plate 6 are made of medical-grade polypropylene material, which has good mechanical properties. When the replacement needle 4 is pressed against the patient's skin, it can fit closely to the patient's skin. The material is inexpensive and can be used once. It is replaced after each injection to ensure the hygiene of the injection head. Medical-grade polypropylene has high toughness. Pressing the compression plate 6 can deform the compression plate 6 to squeeze the fixing block 9 and remove and replace the replacement needle 4.

[0027] Please refer to the details. Figures 1-8 A sealing film 12 is fixedly connected to the inner circumference of the liquid outlet 11.

[0028] In this embodiment: the sealing film 12 is an insulating film that blocks the lower opening of the liquid outlet 11. When the liquid medicine is injected into the sliding groove 13, the liquid medicine is blocked by the sealing film 12 and cannot flow out. When the pressure rod 14 applies pressure to the sliding groove 13, the hydraulic pressure in the sliding groove 13 is too large and breaks through the sealing film 12, and the liquid medicine is ejected into the replacement needle 4 to complete the injection.

[0029] Please refer to the details. Figures 1-8The syringe 2 has a drug solution tank 35 inside, and an energy storage tank 34 is provided on the upper inner wall of the drug solution tank 35. A limiting groove 17 is provided on the upper inner wall of the energy storage tank 34. A sliding groove 13 is provided on the lower inner wall of the limiting groove 17, the energy storage tank 34 and the drug solution tank 35. The sliding groove 13 is connected to the liquid outlet 11. A pressure boosting rod 14 is slidably connected in the sliding groove 13. A spring push plate 33 is fixedly connected to the circumferential surface of the pressure boosting rod 14. An energy storage spring 31 is fixedly connected to the upper end of the spring push plate 33 and the upper inner wall of the energy storage tank 34.

[0030] In this embodiment: the medicine tank 35 is a medicine storage tank to store medicine liquid, the sliding groove 13 connects multiple grooves and the pressure boosting rod 14 slides in the sliding groove 13, and the energy storage spring 31 is fixed between the spring push plate 33 and the inner wall of the energy storage tank 34. Under normal conditions, the energy storage spring 31 abuts against the spring push plate 33 and inserts the pressure boosting rod 14 into the bottom end of the sliding groove 13 to prevent the medicine liquid from flowing out.

[0031] Please refer to the details. Figures 1-8 The booster rod 14 has a support groove 23 on its circumferential surface. The syringe 2 has two sets of fixing components. Each set of fixing components includes a second spring groove 18, a spring push block 19, a second spring 20, a support block 21, and a sliding groove 22. There are two second spring grooves 18, two spring push blocks 19, and two springs 20. The two second spring grooves 18 are opened on the inner circumferential wall of the limiting groove 17. The two spring push blocks 19 are slidably connected to the two second spring grooves 18 respectively. The two second springs 20 are fixedly connected to one side of the spring push block 19 and one side of the inner wall of the second spring groove 18 respectively. The support block 21 is fixedly connected to one side of the two spring push blocks 19 and matches the support groove 23. The sliding groove 22 is opened on the upper end of the support block 21.

[0032] In this embodiment: a fixing component is provided in the limiting groove 17 to support the pressure rod 14 before it pushes out the liquid medicine to complete the injection. When injection is required, the pressure rod 14 is pulled upward. When the pressure rod 14 moves upward, it contacts the inclined surface of the side end of the support block 21. The pressure rod 14 squeezes the inclined surface of the support block 21 and pushes the two support blocks 21 to move outward. At the same time as the support blocks 21 move outward, the second spring 20 is squeezed and contracted. When the pressure rod 14 moves to the uppermost end, the position of the support groove 23 is at the same level as the upper end of the support block 21. The second spring 20, which was previously squeezed and contracted, rebounds and pushes the spring pusher 19 to insert the support block 21 into the support groove 23 to fix the position of the pressure rod 14. At the same time as the pressure rod 14 moves upward, the energy storage spring 31 is squeezed and contracted by the spring pusher plate 33. After the pressure rod 14 is fixed, the energy storage spring 31 is always in a contracted state until the injection.

[0033] Please refer to the details. Figures 1-8An injection block 24 is provided at the upper end of the injection housing 1. An injection spring 25 is fixedly connected to the lower end of the injection block 24 and the upper end of the injection housing 1. Two injection inserts 26 are fixedly connected to the lower end of the injection block 24. The two injection inserts 26 are respectively matched with two sliding grooves 22.

[0034] In this embodiment: the injection block 24 slides within the opening at the upper end of the injection housing 1, and an injection spring 25 is fixed between the injection block 24 and the upper end of the injection housing 1. When injection is required, the injection block 24 is pressed down to insert the two injection inserts 26 into the two sliding grooves 22. The contact surface between the sliding grooves 22 and the injection inserts 26 is inclined. As the injection inserts 26 are slowly inserted into the sliding grooves 22, the inclined surface of the injection inserts 26 presses the sliding grooves 22 outward. When the injection inserts 26 are fully inserted into the sliding grooves 22, the support block 21 is pushed by the injection inserts 26. Pulling the booster rod 14 out of the support groove 23 releases its fixed constraint, causing the previously compressed energy storage spring 31 to quickly rebound, pushing the spring push plate 33 and the booster rod 14 downwards. When the booster rod 14 inserts into the lowermost sliding groove 13, it continues to move downwards, squeezing the liquid in the sliding groove 13. The hydraulic pressure in the sliding groove 13 breaks through the sealing membrane 12 and ejects the liquid outlet 11 to complete the injection. By pre-storing the liquid in the fixed components and the liquid tank 35, the device can continuously inject without needing to replenish the liquid after each injection, thus improving injection efficiency.

[0035] Please refer to the details. Figures 1-8 An observation mirror 27 is fixedly connected to one side of the injection shell 1.

[0036] In this embodiment, the observation mirror 27 is located on one side of the injection shell 1 and is at the same horizontal level as the drug tank 35. The remaining amount of drug in the drug tank 35 can be observed through the observation mirror 27 to replenish the drug.

[0037] Please refer to the details. Figures 1-8 A connection hole 28 is provided on one side of the syringe 2. The upper end of the observation mirror 27 is rotatably connected to the energy storage handle 29 via a rotating shaft. A lifting plate 32 is fixedly connected to the circumferential surface of the booster rod 14. A lifting block 30 is fixedly connected to the lower end of the energy storage handle 29. One side of the lifting block 30 slides at the lower end of the lifting plate 32.

[0038] In this embodiment: the energy storage handle 29 is connected to the observation mirror 27 via a rotating shaft. The energy storage handle 29 can rotate at the upper end of the observation mirror 27 via the rotating shaft. A connecting hole 28 is provided on one side of the syringe 2, allowing the lifting block 30 to connect to the lifting plate 32. When injection preparation is required, the energy storage handle 29 can be pulled to one side. Simultaneously, the lifting block 30 is also driven to rotate by the energy storage handle 29. The lifting block 30, along with the rotation of the energy storage handle 29, lifts the lifting plate 32 upwards until the pressure booster 14 moves to the position to be filled. Please refer to the details. Figures 1-8 Two sets of sealing rings are fixedly connected to the upper and lower inner walls of the medicine tank 35.

[0039] In this embodiment, two sets of sealing rings are provided on the upper and lower inner walls of the liquid tank 35 and are sleeved on the outer surface of the pressure booster 14 for sealing, so as to prevent the liquid in the liquid tank 35 from leaking out.

[0040] The working principle and usage process of this invention are as follows: Before needle-free injection, the replacement needle 4 is replaced. The new replacement needle 4 is fitted onto the lower end of the connector 3. When the replacement needle 4 slides upward, it contacts the fixing block 9. The contact surface between the fixing block 9 and the replacement needle 4 is inclined. The replacement needle 4 squeezes the fixing block 9 and slides into the first spring groove 7, and squeezes the first spring 8 to contract. When the replacement needle 4 is completely fitted onto the connector 3, the liquid outlet 11 is aligned with the lower opening of the sliding groove 13, and the previously compressed first spring 8 rebounds, pushing the fixing block 9 into the fixing groove 5 to complete the fixation of the replacement needle 4. This completes the installation of the replacement needle 4. After the replacement needle 4 is installed, the operator rotates the energy storage handle 29 to drive the lifting block 30 to rotate. The lifting block 30 lifts the lifting plate 32 and the pressure rod 14 upward. As the pressure rod 14 slides upward, it compresses the energy storage spring 31 to contract. The pressure rod 14 compresses the inclined surface on one side of the support block 21, pushing the support block 21 towards the side of the second spring groove 18 and compressing the second spring 20 to contract. When the pressure rod 14 moves upward until the support groove 23 matches the position of the sliding inclined groove 22, the previously compressed second spring 20 rebounds and pushes the support block 21. The booster rod 14 is secured in the support groove 23, keeping the energy storage spring 31 in a contracted state. As the booster rod 14 slides upward, a vacuum is created in the sliding groove 13 until the booster rod 14 slides upward out of the sliding groove 13 on the lower inner wall of the liquid tank 35. The liquid in the liquid tank 35 then flows into and fills the outlet hole 11 and the sliding groove 13, thus completing the injection preparation. After the injection preparation is complete, the operator presses the injection block 24. At the same time, the two injection inserts 26 at the lower end of the injection block 24 are inserted into the two sliding inclined grooves 22 respectively. The inclined surfaces of the injection inserts 26 press against the inclined surfaces of the sliding inclined grooves 22. The two sliding grooves 22 are squeezed outward from the support groove 23. The support groove 23 is fixed and restricted. The previously compressed energy storage spring 31 rebounds and pushes the spring push plate 33 and the pressure booster rod 14 into the sliding groove 13. With the high-speed rebound of the pressure booster rod 14, the pressure in the sliding groove 13 is instantly increased, thereby ejecting the liquid in the outlet hole 11 to complete the injection. After the injection is completed, the operator presses the two squeeze plates 6 on both sides. The two squeeze plates 6 squeeze the fixing block 9 back into the first spring groove 7 to release the fixation of the replacement needle 4. Then the replacement needle 4 is pulled out and replaced with a new replacement needle 4 for the next injection.

[0041] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A handheld needle-free injection device, characterized in that: include: Injection shell (1); Injection cartridge (2), which is disposed inside the injection shell (1); Connector (3), which is fixedly connected to the lower end of the syringe (2); Replace the needle (4), which is slidably connected to the outer surface of the connector (3); The replacement assembly is provided in two sets. Each set of the replacement assembly includes a fixing groove (5), a squeezing plate (6), a first spring groove (7), a first spring (8), a fixing block (9), a pressing groove (10), and a liquid outlet (11). The pressing groove (10) is opened on one side of the replacement needle (4). The fixing groove (5) is opened on one side of the inner wall of the pressing groove (10). The first spring groove (7) is opened on one side of the connector (3). The fixing block (9) is slidably connected in the first spring groove (7) and the fixing groove (5). The first spring (8) is fixedly connected to one side of the inner wall of the first spring groove (7) and one side of the fixing block (9). The squeezing plate (6) is fixedly connected to the lower inner wall of the pressing groove (10). The liquid outlet (11) is opened at the lower end of the replacement needle (4).

2. The handheld needle-free injection device according to claim 1, characterized in that: The replacement needle (4) and the compression plate (6) are both made of medical-grade polypropylene material.

3. The handheld needle-free injection device according to claim 2, characterized in that: A sealing film (12) is fixedly connected to the inner circumference of the liquid outlet (11).

4. A handheld needle-free injection device according to claim 3, characterized in that: The syringe (2) is provided with a liquid tank (35), and the upper inner wall of the liquid tank (35) is provided with an energy storage tank (34). The upper inner wall of the energy storage tank (34) is provided with a limiting groove (17). The lower inner wall of the limiting groove (17), the energy storage tank (34) and the liquid tank (35) is provided with a sliding groove (13). The sliding groove (13) is connected to the liquid outlet (11). A pressure boosting rod (14) is slidably connected in the sliding groove (13). A spring push plate (33) is fixedly connected to the circumferential surface of the pressure boosting rod (14). An energy storage spring (31) is fixedly connected to the upper end of the spring push plate (33) and the upper inner wall of the energy storage tank (34).

5. A handheld needle-free injection device according to claim 4, characterized in that: The booster rod (14) has a support groove (23) on its circumferential surface. The syringe (2) has two sets of fixing components. Each set of fixing components includes a second spring groove (18), a spring push block (19), a second spring (20), a support block (21), and a sliding groove (22). There are two second spring grooves (18), two spring push blocks (19), and two springs (20). The two second spring grooves (18) are opened on the inner circumferential wall of the limiting groove (17). The two spring push blocks (19) are slidably connected in the two second spring grooves (18). The two second springs (20) are fixedly connected to one side of the spring push block (19) and one side of the inner wall of the second spring groove (18). The support block (21) is fixedly connected to one side of the two spring push blocks (19) and matches the support groove (23). The sliding groove (22) is opened at the upper end of the support block (21).

6. A handheld needle-free injection device according to claim 5, characterized in that: An injection block (24) is provided at the upper end of the injection housing (1). An injection spring (25) is fixedly connected to the lower end of the injection block (24) and the upper end of the injection housing (1). Two injection inserts (26) are fixedly connected to the lower end of the injection block (24). The two injection inserts (26) are respectively matched with two sliding grooves (22).

7. A handheld needle-free injection device according to claim 6, characterized in that: An observation mirror (27) is fixedly connected to one side of the injection shell (1).

8. A handheld needle-free injection device according to claim 7, characterized in that: The syringe (2) has a connection hole (28) on one side. The upper end of the observation mirror (27) is rotatably connected to the energy storage handle (29) via a rotating shaft. The circumferential surface of the booster rod (14) is fixedly connected to the lifting plate (32). The lower end of the energy storage handle (29) is fixedly connected to the lifting block (30). One side of the lifting block (30) slides at the lower end of the lifting plate (32).

9. A handheld needle-free injection device according to claim 8, characterized in that: The upper and lower inner walls of the liquid tank (35) are fixedly connected with two sets of sealing rings.

10. The method of using a handheld needle-free injection device according to claim 9, characterized in that: Includes the following steps: S1. Before performing needleless injection, replace the replacement needle (4) by placing the new replacement needle (4) on the lower end of the connector (3). When the replacement needle (4) slides upward, it contacts the fixing block (9). The contact surface between the fixing block (9) and the replacement needle (4) is inclined. The replacement needle (4) squeezes the fixing block (9) into the first spring groove (7) and squeezes the first spring (8) to contract. When the replacement needle (4) is completely covered outside the connector (3), the liquid outlet (11) is aligned with the lower opening of the sliding groove (13), and the first spring (8) that was previously squeezed and contracted rebounds to push the fixing block (9) into the fixing groove (5) to complete the fixing of the replacement needle (4) and thus complete the installation of the replacement needle (4). S2. After the needle replacement (4) is installed, the operator rotates the energy storage handle (29) to drive the lifting block (30) to rotate. The lifting block (30) lifts the lifting plate (32) and the pressure rod (14) upward. While the pressure rod (14) slides upward, it squeezes the energy storage spring (31) to contract. The pressure rod (14) squeezes the inclined surface on one side of the support block (21), pushing the support block (21) towards one side of the second spring groove (18) and squeezing the second spring (20) to contract. When the pressure rod (14) moves upward to the support groove (23) and the sliding inclined groove (28), the pressure rod (14) moves upward to the support groove (23) and the sliding inclined groove (28) to contract. 2) After the positions are matched, the second spring (20) that was previously squeezed and contracted rebounds and pushes the support block (21) into the support groove (23) to complete the fixation of the booster rod (14) and keep the energy storage spring (31) in a contracted state. While the booster rod (14) slides upward, a vacuum is generated in the sliding groove (13) until the booster rod (14) slides upward out of the sliding groove (13) opened on the lower inner wall of the liquid tank (35). The liquid in the liquid tank (35) will flow into and fill the outlet hole (11) and the sliding groove (13), thus completing the injection preparation. S3. After the injection preparation is completed, the operator presses the injection block (24). At the same time, the two injection inserts (26) at the lower end of the injection block (24) are inserted into the two sliding grooves (22) respectively. The inclined surface of the injection insert (26) presses the inclined surface of the sliding groove (22) and the two sliding grooves (22) slide outward into the support groove (23). The fixed restriction of the support groove (23) is contacted, and the previously compressed energy storage spring (31) rebounds and pushes the spring push plate (33) and the pressure rod (1) 4) Insert into the sliding groove (13), and with the high-speed rebound of the booster rod (14), instantly increase the pressure in the sliding groove (13), thereby ejecting the liquid in the outlet hole (11) to complete the injection. After the injection is completed, the operator presses the two squeeze plates (6) on both sides, and squeezes the fixing block (9) back into the first spring groove (7) through the two squeeze plates (6) to release the fixing of the replacement needle (4). Then, pull out the replacement needle (4) and replace it with a new replacement needle (4) for the next injection.

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