Push rod reset mechanism for needle-free syringe

Abstract

The present invention relates to the technical field of needle-free syringes, in particular to a push rod reset mechanism of a needle-free syringe, comprising an oil storage cylinder for storing hydraulic oil, a pull rod and a reset piston fixed at the front end of the pull rod, the oil storage cylinder is fixed on a gun body, the reset piston is slidably installed in the oil storage cylinder, a valve body is fixed at the front end of the gun body, an oil return flow channel is provided in the valve body, the outer end of the oil return flow channel is connected with the front end of the oil storage cylinder, the inner end of the oil return flow channel is connected with the part between the stepping piston and the hydraulic piston, an oil return one-way valve for preventing the hydraulic oil between the stepping piston and the hydraulic piston from entering the oil storage cylinder is provided in the oil return flow channel, the present invention unlocks the oil return one-way valve through a one-way unlocking structure, and the oil return flow channel is opened, so that when the pull rod is pulled backward, the hydraulic oil between the stepping piston and the hydraulic piston can be drawn into the oil storage cylinder through the oil return flow channel, thereby realizing the reset of the stepping piston and the push rod fixed on the stepping piston, the operation is simple, and the reset accuracy is high.

Description

Technical Field

[0001] The invention relates to the technical field of needle-free syringes, in particular to a push rod resetting mechanism of a needle-free syringe. Background Art

[0002] The working principle of the needle-free syringe is to use the power source to release power to generate instant high pressure, which pushes the liquid medicine to spray out from the micron-sized pores. The high-speed liquid medicine flow will instantly penetrate the skin and reach the subcutaneous tissue, so that the liquid medicine can be diffused and distributed in the subcutaneous tissue, with a faster onset time and a higher drug absorption rate.

[0003] Needle-free syringes generally use a power mechanism to push a push rod to move at high speed in a straight line, so that the push rod quickly pushes the drug solution to form an injection, and then resets the push rod after the injection. However, existing needle-free syringes usually use a push rod to directly push the push rod to reset, which makes the operation complicated and the reset accuracy low. Summary of the invention

[0004] The technical problem to be solved by the present invention is: in order to solve the problem that the needle-free syringe in the prior art usually adopts the method of directly pushing the push rod by the push rod to reset when resetting, resulting in complicated operation and low resetting accuracy, a push rod resetting mechanism for a needle-free syringe is provided.

[0005] The technical solution adopted by the present invention to solve its technical problems is: a push rod reset mechanism for a needle-free syringe, the needle-free syringe comprises a gun body, an external hydraulic tube, an internal hydraulic tube and a power mechanism, the internal hydraulic tube is fixed in the gun body, the external hydraulic tube is fixed at the front end of the gun body, the tail end of the external hydraulic tube is connected with the head end of the internal hydraulic tube, a push rod for injection is arranged in the external hydraulic tube, a stepping piston is fixed at the tail end of the push rod, the stepping piston is slidably installed in the external hydraulic tube, a hydraulic piston is slidably installed in the internal hydraulic tube, the power mechanism is used to drive the hydraulic piston to reciprocate along the axial direction of the internal hydraulic tube, and the push rod The reset mechanism includes an oil storage cylinder for storing hydraulic oil, a pull rod and a reset piston fixed at the front end of the pull rod. The oil storage cylinder is fixed on the gun body, and the reset piston is slidably installed in the oil storage cylinder. A valve body is fixed to the front end of the gun body, and an oil return channel is opened in the valve body. The outer end of the oil return channel is connected to the front end of the oil storage cylinder, and the inner end of the oil return channel is connected to the part between the stepping piston and the hydraulic piston. The oil return channel is provided with an oil return check valve for preventing the hydraulic oil between the stepping piston and the hydraulic piston from entering the oil storage cylinder, and the valve body is provided with a one-way unlocking structure for unlocking the oil return check valve to make the oil return channel unobstructed.

[0006] In this solution, the return oil one-way valve is unlocked by a one-way unlocking structure, and the return oil flow channel is opened. Therefore, when the pull rod is pulled backward, the hydraulic oil between the stepping piston and the hydraulic piston can be drawn into the oil storage cylinder through the return oil flow channel, thereby realizing the resetting of the stepping piston and the push rod fixed on the stepping piston. The operation is simple and the resetting accuracy is high.

[0007] Furthermore, a screw sleeve is threadedly connected to the tail end of the oil storage cylinder, and the front end of the screw sleeve extends into the oil storage cylinder, and the pull rod passes through the screw sleeve; by rotating the screw sleeve, the distance between the screw sleeve and the front end of the oil storage cylinder is changed, thereby changing the maximum distance that the pull rod can be pulled backward, so that the displacement of the push rod moving backward can be accurately adjusted according to the injection dose; specifically, according to the next injection dose, after adjusting the position of the screw sleeve, the pull rod is pulled backward until the front end end of the reset piston screw sleeve contacts, thereby completing the reset of the push rod. When the screw sleeve is twisted and moved forward, it means that the stroke of the pull rod becomes shorter and the displacement of the push rod reset is small. When the screw sleeve is twisted and moved backward, it means that the stroke of the pull rod becomes longer and the displacement of the push rod reset is large.

[0008] Furthermore, an injection check valve is provided between the inner hydraulic pipe and the outer hydraulic pipe, a first oil chamber containing hydraulic oil is formed between the hydraulic piston and the injection check valve, a second oil chamber is formed between the injection check valve and the stepping piston, the hydraulic oil in the first oil chamber can reach the second oil chamber through the injection check valve, and the inner end of the return oil channel is connected to the second oil chamber; the injection check valve can prevent the hydraulic oil in the second oil chamber from returning to the first oil chamber.

[0009] Furthermore, the oil return one-way valve comprises an oil return plug, an oil return spring, a sealing ball and a valve seat, a valve hole is formed on the valve seat, the valve seat is arranged in the oil return flow channel, and the valve hole of the valve seat is communicated with the oil return flow channel, the oil return plug and the valve seat are both fixed in the valve body, the oil return spring and the sealing ball are both located between the oil return plug and the valve seat, one end of the oil return spring abuts against the oil return plug, and the other end abuts against the sealing ball, and the sealing ball blocks the valve hole;

[0010] The one-way unlocking structure comprises a pressure relief button slidably mounted on the valve body, and the pressure relief button is used to push the sealing ball away from the valve seat;

[0011] When the pressure relief button is pressed inward, the pressure relief button pushes the sealing ball away from the valve seat, the oil return spring is compressed, and the sealing ball releases the blockage of the valve hole, thereby allowing the hydraulic oil in the oil return flow channel to flow back.

[0012] Further, the pressure relief button can rotate relative to the valve body, a thin section extends from one end of the pressure relief button close to the sealing ball, an inner arc groove and an outer arc groove are provided on the outer circumference of the pressure relief button, the outer arc groove is located on the side of the inner arc groove away from the sealing ball, the outer arc groove and the inner arc groove are connected, a locking plate is fixed in the valve body, the locking plate is embedded in the inner arc groove, the curvature of the inner arc groove is less than the curvature of the outer arc groove, and a sealing ring is provided between the outer circumference of the pressure relief button and the valve body;

[0013] After the pressure relief button is pressed, the locking plate will relatively reach the outer arc groove, and then the pressure relief button can be rotated to make the locking plate stuck in the outer arc groove, thereby maintaining the pressure relief button in an unlocked state for easy operation. When the pressure relief button is not pressed, the locking plate is embedded in the inner arc groove to prevent the pressure relief button from falling off the valve body.

[0014] Furthermore, the thin section outer sleeve is provided with a compression spring, one end of the compression spring abuts against the valve seat, and the other end abuts against the pressure relief button. The provision of the compression spring can facilitate the resetting of the pressure relief button after being pressed.

[0015] The beneficial effect of the present invention is that the push rod reset mechanism of the needle-free syringe of the present invention unlocks the return oil one-way valve through the one-way unlocking structure, and the return oil flow channel is opened, so that when the pull rod is pulled backward, the hydraulic oil between the stepping piston and the hydraulic piston can be drawn into the oil storage cylinder through the return oil flow channel, thereby realizing the reset of the stepping piston and the push rod fixed on the stepping piston, the operation is simple, and the reset accuracy is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0017] Figure 1 is a schematic diagram of a push rod reset mechanism of a needle-free syringe of the present invention;

[0018] Figure 2 yes Figure 2 A is a partial enlarged schematic diagram;

[0019] Figure 3 It is a schematic diagram of an explosion at a valve body portion in a push rod reset mechanism of a needle-free syringe of the present invention;

[0020] Figure 4 It is a front view schematic diagram of the valve body portion of the push rod reset mechanism of the needle-free syringe of the present invention;

[0021] Figure 5 yes Figure 4 BB-direction cross-sectional view;

[0022] Figure 6 yes Figure 4 Schematic diagram of CC section;

[0023] Figure 7 It is a schematic diagram of the coordination of the pressure relief button and the oil return one-way valve in the push rod reset mechanism of the needle-free syringe of the present invention;

[0024] Figure 8 It is a schematic diagram of a pressure relief button in the push rod reset mechanism of the needle-free syringe of the present invention.

[0025] In the figure: 1, gun body, 101, rodless chamber, 102, rod chamber, 103, air inlet, 104, air outlet, 2, pneumatic piston, 201, piston rod, 3, hydraulic rod, 301, hydraulic piston, 4, inner hydraulic pipe, 5, outer hydraulic pipe, 6, stepping piston, 601, push rod, 7, injection check valve, 8, oil return flow channel, 9, oil return check valve, 901, oil return plug, 902, oil return spring, 903, sealing ball, 904, valve seat, 9041, valve hole;

[0026] 10. Oil storage cylinder, 11. Reset piston, 1101. Pull rod, 12. Valve body, 13. First oil chamber, 14. Second oil chamber, 15. Pressure relief button, 1501. Inner arc groove, 1502. Outer arc groove, 1503. Thin section, 16. Compression spring, 17. Sealing ring, 18. Locking plate, 19. Screw sleeve, 20. Core. DETAILED DESCRIPTION

[0027] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams that only illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention, and directions and references (e.g., up, down, left, right, etc.) may only be used to help describe the features in the drawings. Therefore, the following specific embodiments are not to be taken in a limiting sense, and the scope of the subject matter claimed is limited only by the attached claims and their equivalents.

[0028] Example 1

[0029] like Figure 1-8As shown, a push rod reset mechanism of a needle-free syringe, the needle-free syringe includes a gun body 1, an outer hydraulic tube 5, an inner hydraulic tube 4 and a power mechanism, the inner hydraulic tube 4 is fixed in the gun body 1, the outer hydraulic tube 5 is fixed at the front end of the gun body 1, the tail end of the outer hydraulic tube 5 is connected with the head end of the inner hydraulic tube 4, a push rod 601 for injection is arranged in the outer hydraulic tube 5, a stepping piston 6 is fixed to the tail end of the push rod 601, the stepping piston 6 is slidably installed in the outer hydraulic tube 5, a hydraulic piston 301 is slidably installed in the inner hydraulic tube 4, the power mechanism is used to drive the hydraulic piston 301 to reciprocate along the axial direction of the inner hydraulic tube 4, and the push rod reset mechanism includes an oil storage cylinder for storing hydraulic oil 10, a pull rod 1101 and a reset piston 11 fixed at the front end of the pull rod 1101, the oil storage cylinder 10 is fixed on the gun body 1, the reset piston 11 is slidably installed in the oil storage cylinder 10, a valve body 12 is fixed at the front end of the gun body 1, an oil return channel 8 is opened in the valve body 12, the outer end of the oil return channel 8 is connected to the front end of the oil storage cylinder 10, the inner end of the oil return channel 8 is connected to the part between the stepping piston 6 and the hydraulic piston 301, the oil return channel 8 is provided with an oil return check valve 9 for preventing the hydraulic oil between the stepping piston 6 and the hydraulic piston 301 from entering the oil storage cylinder 10, and the valve body 12 is provided with a one-way unlocking structure for unlocking the oil return check valve 9 to make the oil return channel 8 unobstructed.

[0030] The tail end of the oil storage cylinder 10 is threadedly connected with a screw sleeve 19, and the front end of the screw sleeve 19 extends into the oil storage cylinder 10, and the pull rod 1101 passes through the screw sleeve 19; by rotating the screw sleeve 19, the distance between the screw sleeve 19 and the front end of the oil storage cylinder 10 is changed, thereby changing the maximum distance that the pull rod 1101 can be pulled backward, so that the displacement of the push rod 601 moving backward can be accurately adjusted according to the injection dose; specifically, according to the next injection dose, after adjusting the position of the screw sleeve 19, the pull rod 1101 is pulled backward until the reset piston 11 and the front end of the screw sleeve 19 contact, thereby completing the reset of the push rod 601, when the screw sleeve 19 is twisted and moved forward, it means that the stroke of the pull rod 1101 becomes shorter, and the displacement of the push rod 601 reset is small, and when the screw sleeve 19 is twisted and moved backward, it means that the stroke of the pull rod 1101 becomes longer, and the displacement of the push rod 601 reset is large.

[0031] An injection check valve 7 is provided between the inner hydraulic pipe 4 and the outer hydraulic pipe 5, a first oil chamber 13 for accommodating hydraulic oil is formed between the hydraulic piston 301 and the injection check valve 7, a second oil chamber 14 is formed between the injection check valve 7 and the stepping piston 6, the hydraulic oil in the first oil chamber 13 can reach the second oil chamber 14 through the injection check valve 7, and the inner end of the return oil channel 8 is connected to the second oil chamber 14; the injection check valve 7 can prevent the hydraulic oil in the second oil chamber 14 from returning to the first oil chamber 13.

[0032] The oil return check valve 9 includes an oil return plug 901, an oil return spring 902, a sealing ball 903 and a valve seat 904. The valve seat 904 is provided with a valve hole 9041. The valve seat 904 is arranged in the oil return flow channel 8, and the valve hole 9041 of the valve seat 904 is communicated with the oil return flow channel 8. The oil return plug 901 and the valve seat 904 are both fixed in the valve body 12. The oil return spring 902 and the sealing ball 903 are both located between the oil return plug 901 and the valve seat 904. One end of the oil return spring 902 abuts against the oil return plug 901, and the other end abuts against the sealing ball 903. The sealing ball 903 blocks the valve hole 9041.

[0033] The one-way unlocking structure includes a pressure relief button 15 slidably mounted on the valve body 12, and the pressure relief button 15 is used to push the sealing ball 903 away from the valve seat 904;

[0034] When the pressure relief button 15 is pressed inward, the pressure relief button 15 pushes the sealing ball 903 away from the valve seat 904, the oil return spring 902 is compressed, and the sealing ball 903 releases the blockage of the valve hole 9041, so that the hydraulic oil in the oil return channel 8 can flow back.

[0035] The pressure relief button 15 can rotate relative to the valve body 12. A thin section 1503 extends from one end of the pressure relief button 15 close to the sealing ball 903. An inner arc groove 1501 and an outer arc groove 1502 are provided on the outer circumference of the pressure relief button 15. The outer arc groove 1502 is located on the side of the inner arc groove 1501 away from the sealing ball 903. The outer arc groove 1502 is connected to the inner arc groove 1501. A locking plate 18 is fixed in the valve body 12. The locking plate 18 is embedded in the inner arc groove 1501. The curvature of the inner arc groove 1501 is less than the curvature of the outer arc groove 1502. A sealing ring 17 is provided between the outer circumference of the pressure relief button 15 and the valve body 12.

[0036] After the pressure relief button 15 is pressed, the locking plate 18 will relatively reach the outer arc groove 1502. Then, the pressure relief button 15 can be rotated to make the locking plate 18 stuck in the outer arc groove 1502, thereby maintaining the pressure relief button 15 in an unlocked state for easy operation. When the pressure relief button 15 is not pressed, the locking plate 18 is embedded in the inner arc groove 1501 to prevent the pressure relief button 15 from falling off the valve body 12.

[0037] The thin section 1503 is provided with a pressing spring 16 on its outer sleeve, one end of the pressing spring 16 abuts against the valve seat 904, and the other end abuts against the pressure relief button 15. The setting of the pressing spring 16 can facilitate the reset of the pressure relief button 15 after being pressed.

[0038] In this embodiment, the power mechanism can adopt a pneumatic structure, which may specifically include a pneumatic piston 2. A piston cavity is provided in the gun body 1. The pneumatic piston 2 is slidably installed in the piston cavity. A piston rod 201 is fixed on the pneumatic piston 2. The piston rod 201 is transmission-connected to the hydraulic rod 3. The hydraulic piston 301 is fixed on the hydraulic rod 3. The pneumatic piston 2 divides the piston cavity into a rodless cavity 101 and a rod cavity 102. The piston rod 201 is located in the rod cavity 102. The gun body 1 has an air inlet 103 and an air outlet 104. The air inlet 103 is connected to the rodless cavity 101, and the air outlet 104 is connected to the rod cavity 102. When gas is introduced into the rodless cavity 101, the pneumatic piston 2 moves forward and fires, and the push rod 601 pushes out the liquid medicine in the medicine core 20 at the head end of the outer hydraulic tube 5. When gas is introduced into the rod cavity 102, the pneumatic piston 2 retreats and resets.

[0039] The reset process of the push rod 601 is as follows:

[0040] By pressing the pressure relief button 15 inward, the pressure relief button 15 pushes the sealing ball 903 away from the valve seat 904, the oil return spring 902 is compressed, the sealing ball 903 releases the blockage of the valve hole 9041, and the locking plate 18 relatively reaches the outer arc groove 1502. Then, the pressure relief button 15 is rotated to make the locking plate 18 stuck in the outer arc groove 1502, thereby maintaining the pressure relief button 15 in the unlocked state, which is convenient for operation;

[0041] Then pull the pull rod 1101 backward, the reset piston 11 moves backward, generating suction, and the hydraulic oil in the second oil chamber 14 reaches the oil storage cylinder 10 through the oil return channel 8. As the hydraulic oil in the second oil chamber 14 returns to the oil storage cylinder 10, the stepping piston 6 also moves backward and resets accordingly. After resetting, the pressure relief button 15 is rotated so that the inner arc groove 1501 thereon is opposite to the locking plate 18. After releasing the pressure relief button 15, the pressure relief button 15 is reset under the action of the pressing spring 16, and the oil return check valve 9 resumes the function of preventing the hydraulic oil in the second oil chamber 14 from entering the oil storage cylinder 10.

[0042] The above-mentioned ideal embodiments of the present invention are for inspiration. Through the above-mentioned description, relevant staff can make various changes and modifications without departing from the technical idea of ​​the present invention. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A push rod reset mechanism for a needle-free syringe, the needle-free syringe comprising a gun body (1), an outer hydraulic tube (5), an inner hydraulic tube (4) and a power mechanism, the inner hydraulic tube (4) being fixed in the gun body (1), the outer hydraulic tube (5) being fixed at the front end of the gun body (1), the tail end of the outer hydraulic tube (5) being connected to the head end of the inner hydraulic tube (4), a push rod (601) for injection being arranged in the outer hydraulic tube (5), a stepping piston (6) being fixed at the tail end of the push rod (601), the stepping piston (6) being slidably mounted in the outer hydraulic tube (5), a hydraulic piston (301) being slidably mounted in the inner hydraulic tube (4), the power mechanism being used to drive the hydraulic piston (301) to reciprocate along the axial direction of the inner hydraulic tube (4), characterized in that: The push rod reset mechanism comprises an oil storage cylinder (10) for storing hydraulic oil, a pull rod (1101) and a reset piston (11) fixed to the front end of the pull rod (1101); the oil storage cylinder (10) is fixed on the gun body (1); the reset piston (11) is slidably mounted in the oil storage cylinder (10); a valve body (12) is fixed to the front end of the gun body (1); an oil return flow channel (8) is provided in the valve body (12); the outer end of the oil return flow channel (8) is connected to the front end of the oil storage cylinder (10); the inner end of the oil return flow channel (8) is connected to the portion between the stepping piston (6) and the hydraulic piston (301); an oil return check valve (9) is provided in the oil return flow channel (8) for preventing the hydraulic oil between the stepping piston (6) and the hydraulic piston (301) from entering the oil storage cylinder (10); and a one-way unlocking structure is provided on the valve body (12) for unlocking the oil return check valve (9) to make the oil return flow channel (8) unblocked; An injection check valve (7) is provided between the inner hydraulic pipe (4) and the outer hydraulic pipe (5); a first oil chamber (13) containing hydraulic oil is formed between the hydraulic piston (301) and the injection check valve (7); a second oil chamber (14) is formed between the injection check valve (7) and the stepping piston (6); the hydraulic oil in the first oil chamber (13) can reach the second oil chamber (14) through the injection check valve (7); and the inner end of the oil return channel (8) is in communication with the second oil chamber (14); The oil return check valve (9) comprises an oil return plug (901), an oil return spring (902), a sealing ball (903) and a valve seat (904); a valve hole (9041) is formed on the valve seat (904); the valve seat (904) is arranged in the oil return flow channel (8); the valve hole (9041) of the valve seat (904) is communicated with the oil return flow channel (8); the oil return plug (901) and the valve seat (904) are both fixed in the valve body (12); the oil return spring (902) and the sealing ball (903) are both located between the oil return plug (901) and the valve seat (904); one end of the oil return spring (902) abuts against the oil return plug (901) and the other end abuts against the sealing ball (903); the sealing ball (903) blocks the valve hole (9041); The one-way unlocking structure comprises a pressure relief button (15) slidably mounted on the valve body (12), wherein the pressure relief button (15) is used to push the sealing ball (903) away from the valve seat (904); The pressure relief button (15) is rotatable relative to the valve body (12); a thin section (1503) extends from one end of the pressure relief button (15) close to the sealing ball (903); an inner arc-shaped groove (1501) and an outer arc-shaped groove (1502) are provided on the outer peripheral surface of the pressure relief button (15); the outer arc-shaped groove (1502) is located on the side of the inner arc-shaped groove (1501) away from the sealing ball (903); the outer arc-shaped groove (1502) and the inner arc-shaped groove (1501) are connected; a locking plate (18) is fixed inside the valve body (12); the locking plate (18) is embedded in the inner arc-shaped groove (1501); the curvature of the inner arc-shaped groove (1501) is less than the curvature of the outer arc-shaped groove (1502); and a sealing ring (17) is provided between the outer peripheral surface of the pressure relief button (15) and the valve body (12).

2. The push rod reset mechanism of the needle-free syringe according to claim 1, characterized in that: The rear end of the oil storage cylinder (10) is threadedly connected to a screw sleeve (19), the front end of the screw sleeve (19) extends into the oil storage cylinder (10), and the pull rod (1101) passes through the screw sleeve (19).

3. The push rod reset mechanism of the needle-free syringe according to claim 1, characterized in that: The thin section (1503) is provided with a pressing spring (16) on its outer sleeve, one end of the pressing spring (16) abuts against the valve seat (904), and the other end abuts against the pressure relief button (15).

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