Low-resistance dispensing injector

Abstract

The utility model provides a low-resistance dispensing injector, and belongs to the technical field of injectors. A low-resistance dispensing syringe comprises a needle tube, a push rod is arranged in the needle tube, the push rod comprises a piston rod and a piston, a connecting shaft is fixed to the bottom of the piston rod, and a pressing disc is fixed to the side, away from the piston rod, of the connecting shaft; when no liquid exists, the friction force between the sealing ring and the inner wall of the needle tube is smaller than the elastic force of the reset springs, so that the sealing ring and the inner wall of the needle tube are sealed, and the sealing ring and the inner wall of the needle tube are connected in a sliding mode. When liquid is pushed out or sucked, the piston rod can be pushed or pulled to enable the pressing disc to extrude the sealing ring at the corresponding position, so that the sealing ring at the corresponding position expands outwards, the friction force of the whole piston can be reduced, and the sealing performance of the piston is improved under the condition that the friction force is not changed.

Description

Technical Field

[0001] The utility model belongs to the field of syringes, in particular to a low-resistance medicine dispensing syringe. Background Art

[0002] The emergence of the syringe is an epoch-making revolution in the field of medical devices. The process of extracting and injecting gas or liquid with a needle is called injection. The syringe consists of a syringe with a small hole at the front end and a matching piston core rod. It is used to inject a small amount of liquid or gas into areas that are inaccessible by other methods or to extract it from those places. When the core rod is pulled out, the liquid or gas is sucked from the small hole at the front end of the syringe, and the liquid or gas is squeezed out when the core rod is pushed in.

[0003] When assembling a dispensing syringe, an interference fit is required for the piston to ensure its sealing. However, the interference fit is difficult to install during the assembly process, and when in use, it will cause greater resistance due to its greater friction, which is time-consuming and labor-intensive. Utility Model Content

[0004] The utility model aims at the deficiencies of the prior art and provides a low-resistance medicine dispensing syringe.

[0005] In order to achieve the above-mentioned purpose, the utility model provides the following technical solutions: a low-resistance dispensing syringe, comprising a needle tube, wherein a push rod is arranged in the needle tube, characterized in that: the push rod comprises a piston rod and a piston, a connecting shaft is fixed at the bottom of the piston rod, and a pressure plate is fixed on the side of the connecting shaft away from the piston rod;

[0006] The connecting shaft and the pressure plate are slidably connected with the piston. Return springs are installed on both side end surfaces of the pressure plate. The return springs are in contact with the inside of the piston. The two side end surfaces of the piston are connected together through sealing rings.

[0007] Optionally, a sliding cavity is provided inside the piston, and liquid storage cavities are provided on both sides of the sliding cavity. The pressure plate is located in the sliding cavity, and the return spring abuts against the side end surface of the liquid storage cavity.

[0008] Optionally, the sealing ring is located at the liquid storage cavity, and the liquid storage cavity is filled with a medium.

[0009] Optionally, the sealing ring protrudes outward from the piston, and the material of the sealing ring is one of resin and rubber.

[0010] Optionally, a needle opening is provided at the bottom of the needle tube, and a tube ring is provided on the side of the needle tube away from the needle opening.

[0011] In summary, compared with the prior art, the present invention has the following beneficial effects:

[0012] 1. Due to the setting of the piston, when there is no liquid, the friction between the sealing ring and the inner wall of the needle tube is less than the elastic force of the return spring, so the resistance when pushing and pulling the piston rod can be greatly reduced. When pushing out or sucking liquid, the piston rod can be pushed or pulled to make the pressure plate squeeze the sealing ring at the corresponding position, so that the sealing ring at the corresponding position expands outward, thereby reducing the friction of the piston as a whole and increasing its sealing performance without changing the friction. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a three-dimensional diagram of the utility model.

[0014] Figure 2 It is a half-section view of the utility model.

[0015] Figure 3 For this utility model Figure 2 Enlarged view of point A in the middle.

[0016] 10. Needle tube; 11. Piston rod; 12. Connecting shaft; 13. Piston; 14. Pressure plate; 15. Return spring; 16. Liquid storage chamber; 17. Sliding chamber; 18. Sealing ring; 19. Needle mouth; 20. Cylinder ring. DETAILED DESCRIPTION

[0017] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solution in the embodiment of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiment of the present invention.

[0018] As shown in Figure 1-3, a low-resistance dispensing syringe includes a needle tube 10, a push rod is arranged in the needle tube 10, a needle hole 19 is arranged at the bottom of the needle tube 10, a tube ring 20 is arranged on the side of the needle tube 10 away from the needle hole 19, the push rod includes a piston rod 11 and a piston 13, a connecting shaft 12 is fixed at the bottom of the piston rod 11, a pressure plate 14 is fixed on the side of the connecting shaft 12 away from the piston rod 11, the connecting shaft 12 and the pressure plate 14 are slidably connected with the piston 13, and return springs 15 are installed on both side end faces of the pressure plate 14, the return springs 15 are abutted against the inside of the piston 13, and the two side end faces of the piston 13 are connected together by sealing rings 18.

[0019] A sliding cavity 17 is provided inside the piston 13, and liquid storage cavities 16 are provided on both sides of the sliding cavity 17. The pressure plate 14 is located in the sliding cavity 17, and the return spring 15 abuts against the side end surface of the liquid storage cavity 16. The sealing ring 18 is located in the liquid storage cavity 16, and the liquid storage cavity 16 is filled with a medium. The sealing ring 18 protrudes outward from the piston 13, and the material of the sealing ring 18 is one of resin and rubber.

[0020] When in use, the piston 13 is tightly matched with the needle tube 10 through the raised sealing ring 18, which is easier to install than interference fit and has less friction. Moreover, it only contacts the inner wall of the needle tube 10 through the sealing ring 18, which greatly reduces its contact area, thereby reducing its friction. When the syringe is pushed normally, due to the high air density, it is less difficult to absorb the liquid, that is, when the piston rod 11 is moved, the friction between the needle tube 10 and the piston 13 is less than the elastic force of the return spring 15, so the return springs 15 on both sides will not be compressed, and the tightly matched piston 13 can move in the needle tube 10 more effortlessly. However, when liquid needs to be absorbed, the liquid completely blocks the needle opening 19, and the density of the liquid is relatively large, so its absorption is difficult. There is a certain pressure when taking. At this time, this pressure and the friction between the piston 13 and the inner wall of the needle tube 10 are greater than the elastic force of the return spring 15. Therefore, when sucking liquid, the piston rod 11 can drive the pressure plate 14 to compress the return spring 15 near the piston rod 11, so that the liquid in the liquid storage chamber 16 near the piston rod 11 is squeezed, so that the sealing ring 18 near the piston rod 11 continues to bulge outward to increase the sealing here, and the sealing ring 18 away from the piston rod 11 retracts inward, thereby reducing the overall friction of the piston 13, so that its sealing is increased when the friction remains unchanged. Similarly, when pushing out the liquid, the sealing ring 18 away from the piston rod 11 bulges to increase its sealing.

[0021] Obviously, the described embodiments are only a part of the embodiments of the utility model, not all of them. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the utility model.

Claims

1. A low-resistance dispensing syringe, comprising a needle tube (10), wherein a push rod is provided inside the needle tube (10), characterized in that: The push rod comprises a piston rod (11) and a piston (13); a connecting shaft (12) is fixed to the bottom of the piston rod (11); and a pressure plate (14) is fixed to the side of the connecting shaft (12) away from the piston rod (11); The connecting shaft (12) and the pressure plate (14) are slidably connected with the piston (13); return springs (15) are installed on both side end surfaces of the pressure plate (14); the return springs (15) abut against the inside of the piston (13); and the two side end surfaces of the piston (13) are connected together via a sealing ring (18).

2. A low resistance dispensing syringe according to claim 1, characterized in that: A sliding cavity (17) is provided inside the piston (13), and liquid storage cavities (16) are provided on both sides of the sliding cavity (17). The pressure plate (14) is located in the sliding cavity (17), and the return spring (15) is in contact with the side end surface of the liquid storage cavity (16).

3. A low resistance dispensing syringe according to claim 2, characterized in that: The sealing ring (18) is located at the liquid storage cavity (16), and the liquid storage cavity (16) is filled with a medium.

4. A low resistance dispensing syringe according to claim 1, characterized in that: The sealing ring (18) protrudes outward from the piston (13), and the material of the sealing ring (18) is one of resin and rubber.

5. A low resistance dispensing syringe according to claim 1, characterized in that: The bottom of the needle tube (10) is provided with a needle opening (19), and a tube ring (20) is provided on the side of the needle tube (10) away from the needle opening (19).

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