Drug mixing syringe

Abstract

The medicine mixing injector comprises a sleeve, a middle push rod assembly and a rear push rod assembly which are coaxially sleeved from outside to inside, the middle push rod assembly comprises a middle push rod and a piston body arranged on the outer wall of the middle push rod, the middle push rod is connected into the sleeve in a sliding mode through the piston body, and the rear push rod assembly is connected into the middle push rod in a sliding mode. The front end of the sleeve is provided with an injection port and a matched sealing piece, the front end of the middle push rod is provided with a medicine outlet hole, a matched sealing cover body is installed at the medicine outlet hole, the front end of the middle push rod, the cover body and the sleeve form a front closed cavity, the front end of the rear push rod assembly, the cover body and the middle push rod form a rear closed cavity, and the inner wall of the sleeve is provided with an exhaust groove. The exhaust groove is communicated with the front sealing cavity in a matched mode. The utility model provides the medicine mixing injector which is convenient for exhausting gas and has higher safety.

Description

Technical Field

[0001] This utility model relates to a drug mixing syringe, belonging to the field of medical device technology. Background Technology

[0002] Traditional injection procedures involve first drawing the solvent (i.e., water for injection) into a syringe, then inserting the syringe needle into a solute bottle (for powder or liquid injection), then pushing the solvent and solute out to mix and dissolve, and finally drawing the mixed solution into the syringe before injection into the human body or adding medication to an infusion bottle. This procedure is complex, labor-intensive for nurses, and the medication needs to be transferred several times, making it prone to contamination. To address this, disposable drug-filled syringes, such as those disclosed in application number CN201410024549.4, were developed. However, with these syringes, if there is gas inside after the medication in the rear sealed chamber is pushed into the front sealed chamber for mixing, it is difficult to expel, affecting the safety of the injection. Utility Model Content

[0003] The technical problem to be solved by this utility model is to provide a drug mixing syringe that facilitates the mixing of two drugs while also facilitating the expulsion of gas, thereby improving the safety of injection and overcoming the shortcomings of the prior art.

[0004] The technical solution of this utility model is: a drug mixing syringe, comprising a sleeve, a middle push rod assembly, and a rear push rod assembly coaxially arranged from the outside to the inside. The middle push rod assembly includes a middle push rod and a piston body disposed on the outer wall of the middle push rod. The middle push rod is slidably connected to the sleeve through the piston body, and the rear push rod assembly is slidably connected to the middle push rod. The front end of the sleeve is provided with an injection port and a matching seal. The front end of the middle push rod is provided with a drug outlet hole, and a matching seal is installed at the drug outlet hole. The front end of the middle push rod, the seal, and the sleeve form a front sealed cavity. The front end of the rear push rod assembly, the seal, and the middle push rod form a rear sealed cavity. The inner wall of the sleeve is provided with an exhaust groove, and the exhaust groove is connected to the front sealed cavity.

[0005] Furthermore, the peripheral wall of the middle push rod has a retractable and expandable elastic part. In the initial position, the elastic part is in an expanded state that abuts against the rear end of the sleeve. In this state, the rear push rod assembly can move forward relative to the middle push rod and block the elastic part from retracting, so that the middle push rod cannot move forward relative to the sleeve. The peripheral wall of the rear push rod assembly is provided with a groove. When the rear push rod assembly moves forward to the groove and engages with the elastic part on the middle push rod, the elastic part can retract and release the abutment from the sleeve, and the middle push rod can move forward relative to the sleeve.

[0006] Furthermore, the rear push rod assembly and the middle push rod have a cooperating connection structure. When the rear push rod assembly moves forward to the position where the groove and the elastic part on the middle push rod are engaged, the connection structure engages, and the rear push rod assembly and the middle push rod move forward together relative to the sleeve.

[0007] Furthermore, the connection structure is such that when the rear push rod assembly moves forward to the position where the groove engages with the elastic part on the middle push rod, the rear push rod assembly is flush with the rear end of the middle push rod.

[0008] Furthermore, the rear end of the sleeve has an outwardly expanding gripping portion with an outwardly expanding inner wall, and the elastic portion cooperates with the inner wall of the gripping portion to resist.

[0009] Furthermore, the rear push rod assembly includes a hollow rear push rod and a piston located at the front end of the rear push rod. The rear end of the middle push rod is outwardly flared and has an outwardly flared inner peripheral wall. A positioning mechanism is provided between the inner peripheral wall and the rear push rod to cooperate with the positioning mechanism to keep the rear push rod assembly in the initial position of sliding contact with the middle push rod.

[0010] By implementing this invention, the front sealed chamber and the rear sealed chamber respectively hold two drugs to be mixed. In the initial position before injection, before the drugs are mixed, the front end of the venting groove is located behind the piston body of the middle push rod assembly. At this time, due to the obstruction of the piston body, the front sealed chamber is in a sealed state and is not connected to the venting groove. In use, hold the sleeve with one hand and push the rear push rod assembly forward with the other hand. At this time, the pressure in the rear sealed chamber opens the cover, and the front sealed chamber and the rear sealed chamber are connected. As the rear push rod assembly moves forward, the drugs in the rear sealed chamber are pushed into the front sealed chamber for mixing. This process... As the middle and rear sealed chambers gradually shrink until they disappear, the pressure in the front sealed chamber increases, forcing the middle push rod assembly to move backward. The volume of the front sealed chamber automatically expands to accommodate the mixed medication. The medication in the rear sealed chamber is then pushed into the front sealed chamber. At this point, the front end of the venting groove is located in front of the piston body of the middle push rod assembly and thus communicates with the front sealed chamber. During injection, the rear push rod assembly and the middle push rod assembly are pushed forward relative to the sleeve to eject the mixed medication from the injection port at the front end of the sleeve. If there is air in the front sealed chamber, it will be discharged from the venting groove, achieving automatic venting and improving injection safety. Attached Figure Description

[0011] Figure 1 This is a three-dimensional schematic diagram of the initial state of this utility model;

[0012] Figure 2 This is a cross-sectional view of the present invention in its initial state;

[0013] Figure 3 for Figure 2 Enlarged view of point A;

[0014] Figure 4 A cross-sectional view of the drug being pushed from the rear sealed cavity to the front sealed cavity in this invention.

[0015] Figure 5 A cross-sectional view of the injection state of this utility model.

[0016] The figure shows: sleeve 1; middle push rod 2; piston body 3; seal 4; medicine outlet 5; cover 6; front sealed cavity 7; rear sealed cavity 8; elastic part 9; groove 10; rear push rod 11; piston 12; inner convex ring 13; outer convex ring 14; exhaust groove 15; gripping part 16. Detailed Implementation

[0017] Embodiments of this utility model: such as Figures 1 to 5 As shown, a drug mixing syringe includes a sleeve 1, a middle push rod assembly, and a rear push rod assembly coaxially arranged from the outside to the inside. The middle push rod assembly includes a middle push rod 2 and a piston body 3 disposed on the outer wall of the middle push rod 2. The middle push rod 2 is slidably connected to the sleeve 1 through the piston body 3, and the rear push rod assembly is slidably connected to the middle push rod 2. The front end of the sleeve 1 is provided with an injection port and a matching seal 4. The front end of the middle push rod 2 is provided with a drug outlet 5, and a sealing cap 6 is provided at the drug outlet 5. The front end of the middle push rod 2, the cover 6, and the sleeve 1 form the front sealed cavity 7, and the front end of the rear push rod assembly, the cover 6, and the middle push rod 2 form the rear sealed cavity 8. The front sealed cavity 7 and the rear sealed cavity 8 respectively contain two drugs to be mixed, such as a liquid drug in the front sealed cavity 7 and a different liquid or powder drug in the rear sealed cavity 8. In the initial position before injection, before the drugs are mixed, the front end of the vent groove 15 is located behind the piston body 3 of the middle push rod assembly. At this time, due to the active... With the obstruction of the plug body 3, the front sealing cavity 7 is in a sealed state, not connected to the venting groove 15. During use, hold the sleeve 1 with one hand and push the rear push rod assembly forward with the other. At this time, the pressure in the rear sealed cavity 8 opens the cover body 6, and the front sealing cavity 7 is connected to the rear sealed cavity 8. As the rear push rod assembly moves forward, the drug in the rear sealed cavity 8 is pushed into the front sealed cavity 7 for mixing. During this process, the rear sealed cavity 8 gradually shrinks until it disappears, and the pressure in the front sealed cavity 7 increases, forcing the middle push rod assembly to move backward. The volume of the front sealed cavity 7 automatically expands to accommodate the mixed drug. At this time, the front end of the venting groove 15 is located in front of the piston body 3 of the middle push rod assembly and is therefore connected to the front sealed cavity 7. During injection, remove the seal 4 and push the rear push rod assembly and the middle push rod assembly forward relative to the sleeve 1 to eject the mixed drug from the injection port at the front end of the sleeve 1. If there is air in the front sealed cavity 7, it will be discharged from the venting groove 15, realizing automatic venting and improving the safety of injection.

[0018] As a preferred embodiment, the peripheral wall of the middle push rod 2 has an elastic portion 9, which can expand and contract relative to the peripheral wall of the middle push rod 2. The peripheral wall of the rear push rod assembly is provided with a groove 10 that mates with the elastic portion 9. In the initial position, the elastic portion 9 is in an expanded state that abuts against the rear end of the sleeve 1, while the peripheral wall of the rear push rod assembly prevents the elastic portion 9 from contracting. At this time, the rear push rod assembly can move forward relative to the middle push rod 2, while the middle push rod 2 cannot move forward relative to the sleeve 1. During the forward movement of the rear push rod assembly relative to the middle push rod 2, the drug in the rear sealed cavity 7 is pushed into the front sealed cavity 8. When the closed cavity 8 disappears, the elastic part 9 on the peripheral wall of the middle push rod 2 corresponds to the groove 10 on the peripheral wall of the rear push rod assembly. When the middle push rod assembly and the rear push rod assembly move forward together relative to the sleeve 1, the elastic part 9 can retract inward to release the resistance to the sleeve 1 when it comes into contact with the inner wall of the sleeve 1. The two can move forward relative to the sleeve 1 to complete the injection of the mixed drug. This makes it convenient to quickly and evenly mix and inject the two drugs. The middle push rod 2 will not move forward relative to the sleeve 1 before the drugs are mixed, which will result in premature injection. This has better safety and stability.

[0019] As a preferred embodiment, the rear push rod assembly and the middle push rod 2 have a cooperating connection structure. When the rear push rod assembly moves forward to the position where the groove 10 and the elastic part 9 on the middle push rod 2 are engaged, the connection structure engages. The connection structure can be a cooperating snap-fit ​​structure or a blocking mechanism located between the rear push rod assembly and the middle push rod 2. When the rear push rod assembly moves forward relative to the middle push rod 2 and pushes the drug in the rear sealed cavity 7 into the front sealed cavity 8 (i.e., when the rear sealed cavity 8 disappears), when the elastic part 9 on the peripheral wall of the middle push rod 2 corresponds to the groove 10 on the peripheral wall of the rear push rod assembly, the connection structure connects the rear push rod assembly and the middle push rod 2, so that the two automatically move forward together relative to the sleeve 1 to realize the injection of the mixed drug, making the injection operation more convenient.

[0020] As a preferred option, to facilitate production and installation, a simpler structure is used to connect the middle push rod 2 and the rear push rod assembly. When the rear end of the rear push rod assembly is fully inserted into the middle push rod 2, that is, when the rear push rod assembly and the rear end of the middle push rod 2 are flush, the groove 10 at the rear push rod assembly and the elastic part 9 on the middle push rod 2 cooperate and correspond, so that they can be pushed forward together to realize the injection operation.

[0021] As a preferred embodiment, the rear end of the sleeve 1 has an outwardly flared gripping part 16 with an outwardly flared inner wall. The elastic part 9 cooperates with the inner wall of the gripping part 16 to resist. The outwardly flared gripping part 16 is easy to hold and operate. When in use, one hand holds the gripping part 16 and the other hand pushes the push rod assembly. The outwardly flared inner wall plays a guiding role, which facilitates the installation of the push rod assembly in the sleeve 1 and also helps to resist and guide the elastic part 9, so that it can be retracted more smoothly.

[0022] As a preferred embodiment, the rear push rod assembly includes a hollow rear push rod 11 and a piston 12 located at the front end of the rear push rod 11. The rear end of the middle push rod 11 is outwardly flared and has an outwardly flared inner peripheral wall. A positioning mechanism is provided between the inner peripheral wall and the rear push rod 11. The positioning mechanism includes an inner convex ring 13 located on the inner peripheral wall at the rear end of the middle push rod 11 and an outer convex ring 14 located on the peripheral wall of the rear push rod 11. The initial position of the outer convex ring 14 is located behind the inner convex ring 12, which plays a certain role in blocking the rear push rod assembly 11 from moving forward relative to the middle push rod assembly, thereby preventing misoperation. When the force pushing the rear push rod assembly 11 is large enough, the two objects resist each other and deform, causing the outer convex ring 14 to pass through the inner convex ring 13 to achieve the sliding of the rear push rod assembly relative to the middle push rod assembly. The hollow rear push rod 11 makes it easy to deform and pass smoothly, while also saving materials.

Claims

1. A drug mixing syringe, comprising a sleeve, a middle push rod assembly, and a rear push rod assembly coaxially arranged from the outside to the inside, the middle push rod assembly including a middle push rod and a piston body disposed on the outer wall of the middle push rod, the middle push rod slidingly connected to the sleeve via the piston body, the rear push rod assembly slidingly connected to the middle push rod, the front end of the sleeve having an injection port and a matching seal, the front end of the middle push rod having a drug outlet, a matching seal cap installed at the drug outlet, the front end of the middle push rod, the cap and the sleeve forming a front sealed cavity, the front end of the rear push rod assembly, the cap and the middle push rod forming a rear sealed cavity, characterized in that: The inner wall of the sleeve is provided with an exhaust groove, which is connected to the front sealing cavity.

2. The drug mixing syringe according to claim 1, characterized in that: The peripheral wall of the middle push rod has an elastic part that can be retracted and expanded. In the initial position, the elastic part is in an expanded state that abuts against the rear end of the sleeve. In this state, the rear push rod assembly can move forward relative to the middle push rod and block the elastic part from retracting, so that the middle push rod cannot move forward relative to the sleeve. The peripheral wall of the rear push rod assembly is provided with a groove. When the rear push rod assembly moves forward to the groove and engages with the elastic part on the middle push rod, the elastic part can retract and release the abutment from the sleeve, and the middle push rod can move forward relative to the sleeve.

3. The drug mixing syringe according to claim 1, characterized in that: The rear push rod assembly and the middle push rod have a cooperating connection structure. When the rear push rod assembly moves forward to the position where the groove and the elastic part on the middle push rod are engaged, the connection structure engages, and the rear push rod assembly and the middle push rod move forward together relative to the sleeve.

4. The drug mixing syringe according to claim 3, characterized in that: The connection structure is such that when the rear push rod assembly moves forward to the position where the groove engages with the elastic part on the middle push rod, the rear push rod assembly is flush with the rear end of the middle push rod.

5. The drug mixing syringe according to claim 1, characterized in that: The sleeve has an outwardly expanding gripping part at its rear end, and the gripping part has an outwardly expanding inner wall. The elastic part cooperates with the inner wall of the gripping part to resist.

6. The drug mixing syringe according to any one of claims 1 to 4, characterized in that: The rear push rod assembly includes a hollow rear push rod and a piston located at the front end of the rear push rod. The rear end of the middle push rod is outwardly flared and has an outwardly flared inner peripheral wall. A positioning mechanism is provided between the inner peripheral wall and the rear push rod to cooperate with the positioning mechanism to keep the rear push rod assembly in the initial position of sliding contact with the middle push rod.

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