Prefilled syringe and its plunger

Abstract

This invention provides a pre-filled syringe, including a barrel containing a piston and a push rod. A flange is located at the rear end of the barrel, and a push handle is mounted on the flange. The push handle engages with the flange via a slot with a side opening, and the upper and lower sides of the slot communicate with an upper through slot and a lower through slot, respectively. A push plate abuts against the piston at the front end of the push rod. The push rod is configured such that its shaft can pass through the upper through slot, but its push plate cannot. This eliminates the need for a complex connection between the push plate and the piston; they simply abut against each other, simplifying manufacturing and assembly and reducing costs. The push plate can push the piston forward but cannot pull it back, preventing repeated use of the syringe and the resulting medical waste contamination. Furthermore, the upper through slot of the push handle restricts the push plate's passage, ensuring the push rod does not detach from the barrel during transport, resulting in better performance.

Description

Technical Field

[0001] This utility model belongs to the field of medical device technology, specifically relating to a pre-filled syringe and its plunger. Background Technology

[0002] Prefilled syringes (PFS) are a new type of high-end packaging material that can be directly filled with medication and used for injection. They combine the functions of a drug packaging container and a syringe into one. They can be used directly to fill medication during drug production and directly for injection during drug use, eliminating the traditional step of removing medication from ampoules or vials with a syringe. This makes them very convenient for healthcare professionals and patients to use. Due to these advantages, prefilled syringes are particularly widely used in biological agents.

[0003] Currently, pre-filled syringes have their plunger and piston fixedly connected or threaded together. This not only requires the fabrication of a complex connection structure but also makes the assembly process more cumbersome and increases costs. Furthermore, the plunger in this design can both push the piston forward and pull it back, allowing for reuse. Pre-filled syringes, however, are typically disposable; once the pre-filled medication is injected, the entire syringe is discarded as medical waste. Because the piston can be pulled back, the product may be recycled and reused after its initial use. Utility Model Content

[0004] This invention aims to solve the problems of the prior art by providing a pre-filled syringe and its plunger. By setting a push plate structure at the front end of the plunger, and allowing the pull-back push plate to detach freely from the piston, it facilitates production and assembly and prevents the piston from being pulled back for reuse. At the same time, during transportation, the push plate structure and the push handle work together to prevent the plunger from falling off the syringe barrel.

[0005] This pre-filled syringe includes a barrel containing a piston and a plunger. A flange is located at the rear end of the barrel, and an assist handle is mounted on the flange. The assist handle engages with the flange via a slot with a side opening, and the upper and lower sides of the slot communicate with an upper through slot and a lower through slot, respectively. The plunger has a push plate at its front end that abuts against the piston. The plunger is configured such that its shaft can pass through the upper through slot, but its push plate cannot. This design eliminates the need for a complex connection between the push plate and the piston; they simply abut against each other, simplifying manufacturing and assembly and reducing costs. The push plate can push the piston forward but cannot pull it back, preventing repeated use of the syringe and the resulting medical waste contamination. Furthermore, the upper through slot on the assist handle restricts the push plate's passage, ensuring the plunger does not detach from the barrel during transport, resulting in better performance.

[0006] Preferably, the push plate is circular, with a diameter greater than the width of the upper through groove, and the width of the upper through groove is greater than the width of the rod body. With this structure, the push rod can slide freely within the cylinder without detaching from it, thus meeting the usage requirements.

[0007] Preferably, the push plate has a connector at its front end and a socket at its rear end that mates with the connector. The connector engages with the socket in a way that allows it to detach freely. This allows the push plate to push the piston forward more easily without pulling it back.

[0008] Preferably, the rod is in the shape of a quadrangular prism, with reinforcing structures supporting the four edges; multiple reinforcing structures are evenly spaced along the rod. This gives the push rod sufficient strength while reducing cost and improving its performance.

[0009] Preferably, the edge is provided with a demolding force block. In this way, force can be applied at the demolding force block during demolding, which facilitates demolding and ensures that the edge will not deform.

[0010] Preferably, the reinforcing structure protrudes outward from the shaft. This prevents the reinforcing structure from passing through the upper slot, allowing for adjustment of the maximum pre-filled medication volume of the syringe, resulting in more precise medication filling and avoiding unnecessary waste.

[0011] This invention also provides a plunger for the aforementioned pre-filled syringe, comprising a shaft with a push plate protruding outward from the front end of the shaft. This eliminates the need for complex connections between the plunger tip and the piston, resulting in low production costs while meeting the requirements of disposable pre-filled syringes and preventing the reuse of medical waste.

[0012] Preferably, the pusher plate has a connector at its front end, and the sidewall surface of the connector is smooth. This makes it easier to push the piston forward while preventing it from being pulled back.

[0013] The shaft is shaped like a four-sided prism, with reinforcing structures supporting the four edges; multiple reinforcing structures are evenly spaced along the shaft. This type of putter offers sufficient strength while reducing costs and providing excellent performance.

[0014] The reinforced structure protrudes outward from the rod. This type of push rod allows for adjustment of the maximum pre-filled medication volume of the disposable pre-filled syringe, resulting in more precise medication filling and preventing unnecessary waste.

[0015] The disposable pre-filled syringe and its plunger provided by this utility model have at least the following advantages:

[0016] This invention simplifies the connection structure between the plunger and piston without affecting normal use. It is low-cost, effective, and conducive to widespread adoption. Furthermore, it avoids the repeated use of disposable pre-filled syringes, thus preventing medical waste pollution. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the pre-filled syringe of this utility model;

[0018] Figure 2 This is a cross-sectional view of the pre-filled syringe of this utility model;

[0019] Figure 3 This is a schematic diagram of the structure of the booster handle of this utility model;

[0020] Figure 4 This is a schematic diagram of the push rod of this utility model;

[0021] Figure 5 This is a structural schematic diagram of the push rod of this utility model from another perspective;

[0022] Figure 6 This is a schematic diagram of the mating structure between the push plate and the upper through groove of this utility model;

[0023] Figure 7 This is a schematic diagram of the cooperation structure between the reinforcing structure and the upper through groove in Embodiment 2 of this utility model.

[0024] Explanation of reference numerals in the attached figures:

[0025] Push rod 1, rod body 11, edge 111, push plate 12, plug connector 121, reinforcing structure 13, demolding force block 14, push rod head 15, push handle 2, slot 21, upper through slot 22, lower through slot 23, cylinder 3, cap 4, piston 5, plug hole 51. Detailed Implementation

[0026] The following specific embodiments illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification.

[0027] It should be understood that the structures, proportions, sizes, etc., illustrated in the accompanying drawings of this specification are only for illustrative purposes to aid those skilled in the art and are not intended to limit the implementation of this utility model. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effects and objectives of this utility model, should still fall within the scope of the technical content disclosed in this utility model. Furthermore, the terms such as "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity of description and are not intended to limit the scope of implementation of this utility model. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of implementation of this utility model.

[0028] Example 1: As Figure 1 As shown, the pre-filled syringe provided by this utility model includes a barrel 3, inside which a piston 5 and a push rod 1 are provided. A flange 31 is provided at the rear end of the barrel 3, and a push handle 2 is provided on the flange 31. A cap 4 is provided at the front end of the barrel 1. For ease of description, the direction toward the cap 4 is uniformly referred to as "front" in this patent application text, and conversely, the direction toward the flange 31 is referred to as "rear".

[0029] like Figure 1 , Figure 2 , Figure 3 As shown, the booster handle 2 engages with the flange 31 via a slot 21 with a side opening, and the upper and lower sides of the slot 21 are connected to the upper through slot 22 and the lower through slot 23, respectively. The upper through slot 22 is used for the push rod 1 to pass through, and the push rod 1 can move back and forth within it to push the piston 5. The lower through slot 23 is used for the cylinder 3 to pass through.

[0030] like Figure 2 As shown, the front end of the push rod 1 is provided with a push plate 12 that abuts against the piston 5. In this embodiment, the front end of the push plate 12 is provided with a connector 121, and the rear end of the piston 5 is provided with a connector hole 51 that mates with the connector 121. The connector 121 mates with the connector hole 51 in a freely detachable manner. The side wall surface of the connector 121 is smooth, and the diameter of its front end is no greater than that of its rear end, so that it can easily disengage from the piston 5 when it moves backward. In this way, the push plate 12 can smoothly push the piston 5 forward without pulling it back. Of course, the front end of the push plate 12 may also be without a connector 121, and the push plate 12 and the piston 5 may be completely separated, only abutting against each other when it is necessary to push the piston 5. This still achieves the requirement that the push rod 1 can push the piston 5 forward without pulling it back.

[0031] like Figure 2 , Figure 6As shown, the push rod 1 is configured such that its body 11 can pass through the upper through groove 22, while its push plate 12 cannot. In this embodiment, the push plate 12 is circular, with a diameter greater than the width of the upper through groove 22, and the width of the upper through groove 22 is greater than the width of the body 11. This configuration allows the body 11 to slide freely within the cylinder 3 through the upper through groove 22, while the push plate 12 cannot pass through the upper through groove 22, preventing the entire push rod 1 from detaching from the upper through groove 22. The circular shape of the push plate 12 facilitates better fit with the inner wall of the cylinder. Of course, the push plate 12 does not have to be circular; as long as it has an arc surface supporting it on the inner wall of the cylinder 3, and its maximum width is greater than the width of the upper through groove 22, it can still slide smoothly within the cylinder 3 without detaching from the upper through groove 22, thus meeting the usage requirements. As mentioned above, those skilled in the art can devise various methods to achieve the goal of allowing the body 11 to pass through the upper through groove 22 while preventing the push plate 12 from doing so, which will not be elaborated upon here.

[0032] like Figure 4 , Figure 5 As shown, the rod body 11 is a quadrangular prism, with reinforcing structures 13 supporting the four edges 111; two reinforcing structures 13 are evenly spaced on the rod body 11. The rear end of the push rod 11 has a disc-shaped push rod head 15 for easy thumb pressing. One edge 111 has a total of four demolding force blocks 14, two near the reinforcing structure 13, one near the push plate 12, and one near the push rod head 15.

[0033] This utility model also provides a plunger suitable for disposable pre-filled syringes that can be sold separately, such as... Figure 4 , Figure 5 As shown, the push rod includes a rod body 11, with a push plate 12 protruding outward from the front end of the rod body 11. A connector 121 is located at the front end of the push plate 12. The rod body 11 is a quadrangular prism, with reinforcing structures 13 supporting the four edges 111; two reinforcing structures 13 are evenly spaced on the rod body 11. The rear end of the push rod 11 has a disc-shaped push rod head 15 for easy thumb pressing. One edge 111 has a total of four demolding force blocks 14: two near the reinforcing structure 13, one near the push plate 12, and one near the push rod head 15.

[0034] The usage process of this utility model is as follows:

[0035] Filling with liquid: First, install the cap 4 at the front end of the barrel 3, then prefill the barrel 3 with liquid, then push in the piston 5 to seal the liquid, then install the push rod 1, and finally lock the push handle 2 at the flange 31 of the barrel 3, and then seal the entire prefilled syringe.

[0036] During transportation, the push rod will not fall off the cylinder 3 because the upper through slot 22 restricts the push plate 12.

[0037] Injecting the medication: Remove the cap 4 and attach the needle to the Luer connector at the front end of the cylinder 3. After inserting the needle into the body, use your index and middle fingers to hold the front end of the push handle 2 and press the push rod head 15 with your thumb to push the push rod 1 until the push plate 12 presses against the piston 5. Push the piston 5 forward and then inject all the pre-filled medication.

[0038] After injection, the plunger 1 can no longer pull the piston 5 back, thus avoiding repeated use of the syringe.

[0039] As can be seen from the above, this utility model has low cost, is easy to process, assemble and use, and is conducive to promotion.

[0040] Example 2: As Figure 7 As shown, the difference from Embodiment 1 is that the reinforcing structure 13 protrudes outward from the rod body 11. Thus, the reinforcing structure 13 cannot pass through the upper through groove 22, and in this case, the reinforcing structure 13 can be used as a positioning component to determine the maximum amount of pre-filled liquid in the cylinder 3. An example is given below:

[0041] like Figure 7 As shown, during assembly, adjust the position of the push rod 1 so that the reinforcing structure 13 located at the bottom in the diagram is inside the cylinder 3. Then, lock the push handle 2 onto the flange 31, positioning it between the two reinforcing structures 13. At this time, the reinforcing structure 13 shown in the diagram will not be able to pass upward through the upper through slot 22, and the rod body 11 below it will always be inside the cylinder 3, thus limiting the highest position of the piston 5 inside the cylinder 3, thereby limiting the maximum amount of pre-filled liquid, making the amount of pre-filled liquid more accurate, and avoiding unnecessary waste. It should be noted that at this time, the stroke of the push rod 1 is limited to the distance between the two reinforcing structures 13, and the push rod 1 needs to complete the injection within this stroke. One is located near the push plate 12, and the other is located near the push rod head 15.

[0042] This utility model also provides a plunger suitable for disposable pre-filled syringes that can be sold separately, such as... Figure 4 , Figure 5 As shown, the push rod includes a rod body 11, with a push plate 12 protruding outward from the front end of the rod body 11. A connector 121 is located at the front end of the push plate 12. The rod body 11 is a quadrangular prism, with reinforcing structures 13 supporting the four edges 111; two reinforcing structures 13 are evenly spaced on the rod body 11. The rear end of the push rod 11 has a disc-shaped push rod head 15 for easy thumb pressing. One edge 111 has a total of four demolding force blocks 14: two near the reinforcing structure 13, one near the push plate 12, and one near the push rod head 15.

[0043] The usage process of this utility model is as follows:

[0044] Filling with liquid: First, install the cap 4 at the front end of the barrel 3, then prefill the barrel 3 with liquid, then push in the piston 5 to seal the liquid, then install the push rod 1, and finally lock the push handle 2 at the flange 31 of the barrel 3, and then seal the entire prefilled syringe.

[0045] During transportation, the push rod will not fall off the cylinder 3 because the upper through slot 22 restricts the push plate 12.

[0046] Injecting the medication: Remove the cap 4 and attach the needle to the Luer connector at the front end of the cylinder 3. After inserting the needle into the body, use your index and middle fingers to hold the front end of the push handle 2 and press the push rod head 15 with your thumb to push the push rod 1 until the push plate 12 presses against the piston 5. Push the piston 5 forward and then inject all the pre-filled medication.

[0047] After injection, the plunger 1 can no longer pull the piston 5 back, thus avoiding repeated use of the syringe.

[0048] As can be seen from the above, this utility model has low cost, is easy to process, assemble and use, and is conducive to promotion.

[0049] Example 2: Figure 7 As shown, the difference from Embodiment 1 is that the reinforcing structure 13 protrudes outward from the rod body 11. Thus, the reinforcing structure 13 cannot pass through the upper through groove 22, and in this case, the reinforcing structure 13 can be used as a positioning component to determine the maximum amount of pre-filled liquid in the cylinder 3. An example is given below:

[0050] like Figure 7 As shown, during assembly, adjust the position of push rod 1 so that the reinforcing structure 13 located at the bottom in the diagram is inside the cylinder 3. Then, lock the push handle 2 onto the flange 31, positioning it between the two reinforcing structures 13. At this time, the reinforcing structure 13 shown in the diagram will not be able to pass upward through the upper through slot 22, and the rod body 11 below it will always remain inside the cylinder 3. This limits the highest position of the piston 5 inside the cylinder 3, thereby limiting the maximum amount of pre-filled medication, making the amount of pre-filled medication more accurate, and avoiding unnecessary waste. It should be noted that at this time, the stroke of push rod 1 can only be limited to the distance between the two reinforcing structures 13, and push rod 1 needs to complete the injection within this stroke.

Claims

1. A pre-filled syringe comprising a barrel (3), a piston (5) and a plunger rod (1) arranged inside the barrel (3), a flange (31) arranged at the rear end of the barrel (3), characterized in that, The flange (31) is provided with a push handle (2), which is engaged with the flange (31) through a slot (21) with a side opening, and the upper and lower sides of the slot (21) are connected to the upper through slot (22) and the lower through slot (23) respectively; the front end of the push rod (1) is provided with a push plate (12) that abuts against the piston (5), and the push rod (1) is configured such that its rod body (11) can pass through the upper through slot (22) while its push plate (12) cannot pass through the upper through slot (22).

2. The pre-filled syringe of claim 1, wherein, The push plate (12) is circular, and its diameter is greater than the width of the upper through groove (22), and the width of the upper through groove (22) is greater than the width of the rod body (11).

3. The pre-filled syringe of claim 1, wherein, The front end of the push plate (12) is provided with a connector (121), and the rear end of the piston (5) is provided with a plug hole (51) that cooperates with the connector (121). The connector (121) cooperates with the plug hole (51) in a manner that allows it to be freely detached.

4. The pre-filled syringe of claim 1, wherein, The rod body (11) is in the shape of a quadrangular prism, and a reinforcing structure (13) is supported between the four edges (111); the rod body (11) is provided with multiple reinforcing structures (13) at equal intervals.

5. The pre-filled syringe of claim 4, wherein, The ridge (111) is provided with a demolding force block (14).

6. The pre-filled syringe of claim 4, wherein, The reinforcing structure (13) protrudes outward from the shaft (11).

7. A plunger for a pre-filled syringe comprising a shaft (11), characterised in that, The front end of the rod (11) is provided with a push plate (12) that protrudes outward from the rod (11).

8. The plunger of a pre-filled syringe according to claim 7, wherein, The front end of the push plate (12) is provided with a connector (121), and the side wall surface of the connector (121) is smooth.

9. The plunger of a pre-filled syringe according to claim 7, wherein The rod body (11) is in the shape of a quadrangular prism, and a reinforcing structure (13) is supported between the four edges (111); the rod body (11) is provided with multiple reinforcing structures (13) at equal intervals.

10. The plunger of a pre-filled syringe according to claim 9, wherein, The reinforcing structure (13) protrudes outward from the shaft (11).

Images