Piston for pre-filled syringe

Abstract

The utility model relates to the technical field of pistons for injectors, and aims to solve the problems that pistons are low in sealing performance, force application is inconvenient, and injection force and injection amount cannot be accurately controlled. The utility model provides a piston for a pre-filled syringe. The piston comprises a piston body, the plug body comprises a first end part and a second end part; the first end part is provided with a conical sealing head; a sealing boss is annularly arranged on the outer side wall of the second end part; a plurality of convex rings are arranged between the conical sealing head and the sealing boss at intervals; the convex rings are arranged on the outer wall of the plug body; according to the piston for the pre-filled syringe, the sealing performance and the accuracy in the injection process are guaranteed, and the accumulation and waste of injection liquid and the resistance in the later stage of propelling injection are reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to a piston for pre-filled syringe and specifically relates to a piston for pre-filled syringe. BACKGROUND

[0002] The fit of the pre-filled syringe body directly affects its use adaptability, in addition, the piston sliding property is one of the important detection indexes of the pre-filled syringe, because, when the piston is pushed, a certain resistance will be generated between the piston and the inner wall of the glass needle tube; in actual use, too large force value will cause injection difficulty, and too small force value will cause the risk of too fast and too violent injection;

[0003] In the prior art, a common piston, such as the piston disclosed in the patent with the announcement number CN208641444U, has a conical top hat at one end of the piston and an annular groove for inserting a push rod at the other end; however, during the injection process of pushing the piston by the push rod, local pressure is generated, and thus there is the defect of liquid leakage, and the force cannot be controlled during pushing, thereby causing injection difficulty, too fast injection and other problems;

[0004] Based on the above description, there is an urgent need for a safe injection piston that can prevent the push rod from detaching and reduce the resistance between the push rod and the needle cylinder. SUMMARY

[0005] The utility model aims at providing a piston for pre-filled syringe, which aims to solve the technical problems of low fit of the existing piston, inconvenient force application, and inaccurate control of injection force and injection amount.

[0006] The embodiment of the utility model realizes the following technical scheme:

[0007] A piston for pre-filled syringe, comprising a plug body; the plug body comprises a first end portion and a second end portion; the first end portion is provided with a conical sealing head; the outer side wall of the second end portion is provided with a sealing boss; a plurality of convex rings are arranged between the conical sealing head and the sealing boss; the plurality of convex rings are arranged on the outer wall of the plug body.

[0008] As a preferred, the sealing boss comprises a contraction portion and an expansion portion; the contraction portion is arranged at the opening bottom end of the plug body; the expansion portion is arranged at one end of the plug body close to the convex ring.

[0009] As a preferred, the expansion portion is provided with a groove away from the convex ring.

[0010] As a preferred, the side wall of the convex ring away from the plug body is an arc-shaped side wall; the outer groove wall of the groove away from the plug body and the side top end of the arc-shaped side wall are on the same vertical line.

[0011] Preferably, a flow guide is provided inside the groove cavity.

[0012] Preferably, the plug body has a convex cavity; the top end of the convex cavity extends toward the conical sealing head; and the bottom end of the convex cavity communicates with the opening at the bottom of the plug body.

[0013] Preferably, the bottom of the plug body is provided with multiple limiting components.

[0014] Preferably, the limiting component includes an elastic protrusion and a hemisphere; one end of the elastic protrusion is connected to the inner wall of the plug; the hemisphere is located at the end of the elastic protrusion away from the plug.

[0015] The technical solution of this utility model embodiment has at least the following advantages and beneficial effects:

[0016] This invention features a sealing boss at the end of the plug body away from the conical sealing head. The sealing boss extends towards the end away from the outer wall of the plug body, allowing the sealing boss, the convex ring, and the inner wall of the syringe to form a sealed cavity during the push rod's advancement. During injection, the medication seeps into the sealed cavity, is intercepted by the sealing boss, and then, with subsequent thrust, is squeezed out of the sealed cavity as injection fluid. The squeezed-out injection fluid also acts as a lubricant and reduces drag, thus ensuring a tight seal during injection, reducing fluid accumulation and waste, and minimizing resistance in the later stages of injection. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a first structural schematic diagram of the present invention;

[0019] Figure 2 for Figure 1 A sectional view;

[0020] Figure 3 for Figure 2 An enlarged schematic diagram of the local structure A;

[0021] Figure 4 This is a schematic diagram of the second structure of the present invention;

[0022] Figure 5 for Figure 4 A sectional view;

[0023] Figure 6 For Figure 5 the enlarged schematic view of the local structure B;

[0024] Figure 7 For the third structure schematic view of the utility model;

[0025] Figure 8 For Figure 7 the sectional view;

[0026] Figure 9 For Figure 8 the enlarged schematic view of the local structure C.

[0027] Icon: 1 - plug body, 11 - convex chamber, 2 - conical sealing head, 3 - sealing boss, 4 - convex ring, 5 - flow guide, 6 - limiting assembly, 61 - elastic lug, 62 - hemisphere. DETAILED DESCRIPTION

[0028] Example 1

[0029] Please refer to Figures 1 to 9 , the utility model provides the following technical scheme: a piston for pre-filled syringe, applicable to the situation of connecting the injector piston of push rod.

[0030] Specifically, as Figure 1 And Figure 2 Indicated, a piston for pre-filled syringe, including plug body 1;Plug body 1 includes first end and second end;The first end is provided with conical sealing head 2;The outer side wall of the second end is provided with sealing boss 3;Conical sealing head 2 and sealing boss 3 are spaced apart and provided with a plurality of convex rings 4;A plurality of convex rings 4 are arranged on the outer wall of plug body 1.

[0031] In this embodiment, the conical sealing head 2 can increase the sliding property of the piston, thereby reducing the resistance during injection, so that after connecting the push rod, the injection is easily pushed forward;By setting a plurality of convex rings 4 on the outer side wall of the plug body 1 at intervals, the sliding property is ensured, and a certain resistance is generated, so that the resistance is appropriate during the injection process, and the injection force, speed and injection volume cannot be accurately controlled due to excessive or insufficient resistance;Further, the sealing boss 3 is arranged at the end of the plug body 1 away from the conical sealing head 2, and the sealing boss 3 extends away from the outer side wall of the plug body 1, so that the sealing boss 3, the convex ring 4 and the inner wall of the injection barrel form a sealed cavity during the pushing process of the push rod, so that the drug solution penetrates into the sealed cavity during the injection process, is intercepted by the sealing boss 3, and is squeezed out again as injection liquid under the subsequent thrust, and the injection liquid can also play a role in lubrication and resistance reduction, so that the tightness during the injection process is ensured, and the accumulation and waste of injection liquid and the resistance in the late injection process are reduced.

[0032] Specifically, as shown in Figure 3 , the sealing boss 3 comprises a contraction part and an expansion part; the contraction part is arranged at the opening bottom end of the plug body 1; and the expansion part is arranged at one end of the plug body 1 close to the convex ring 4.

[0033] In this embodiment, the cross section of the sealing boss 3 is a right-angled trapezoid, the contraction part corresponds to one end of the parallel short side of the right-angled trapezoid, and the expansion part corresponds to one end of the parallel long side of the right-angled trapezoid, and the expansion part is arranged at one end of the plug body 1 close to the convex ring 4, so that the resistance during pushing can be reduced, and the stability of the sealing boss 3 can be ensured.

[0034] Specifically, as shown in Figures 4 to 6 , the expansion part is provided with a groove facing the convex ring 4. The side wall of the convex ring 4 away from the plug body 1 is an arc-shaped side wall; and the outer groove wall of the groove away from the plug body 1 is a vertical line with the side top end of the arc-shaped side wall.

[0035] In this embodiment, the groove is provided on the expansion part facing the convex ring 4, and the groove can further play the role of liquid accumulation, thereby further improving the tightness of the plug body 1 during injection.

[0036] Specifically, as shown in Figures 7 to 9 , a flow guide piece 5 is arranged in the groove cavity of the groove.

[0037] In this embodiment, the flow guide piece 5 is a ring body provided with a flow guide slope surface, and the slope surface is inclined from high to low to the outer side wall of the plug body 1, so that the drug liquid infiltrating into the sealing cavity can be guided to the plug body 1 during pushing, thereby avoiding the drug liquid from being further squeezed out of the sealing cavity, and further improving the sealing performance of the piston.

[0038] Specifically, as shown in Figure 2 or Figure 5 , a convex chamber 11 is arranged in the plug body 1; the top end of the convex chamber 11 extends to the conical sealing head 2; and the bottom end of the convex chamber 11 is in communication with the opening at the bottom of the plug body 1.

[0039] In this embodiment, the top end of the convex chamber 11 is narrow, thereby enhancing the strength and hardness of the end portion of the plug body 1.

[0040] Specifically, as shown in Figure 3 or Figure 6 , a plurality of limiting assemblies 6 are arranged in the bottom of the plug body 1. The limiting assembly 6 comprises an elastic lug 61 and a hemispherical body 62; one end of the elastic lug 61 is connected to the inner side wall of the plug body 1; and the hemispherical body 62 is arranged at the end of the elastic lug 61 away from the plug body 1.

[0041] In the embodiment, the push rod is provided with a clamping groove structure matched with the limiting assembly 6, so as to further improve the stability of the push rod extruded and embedded into the convex chamber 11; wherein the hemispherical body 62 is vertically arranged at one end of the elastic lug 61 away from the inner side wall of the plug body 1, and is clamped into the clamping groove of the push rod through the elastic lug 61, so as to play a clamping and limiting role, and the hemispherical body 62 can not only play a role of reducing the abrasion of the push rod during installation, but also play a role of being embedded into the clamping groove of the push rod for limiting.

[0042] The preferred embodiments of the utility model are merely used for limiting the utility model, and the utility model can be variously changed and varied for the person skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the utility model should be included in the protection scope of the utility model.

Claims

1. A piston for a pre-filled syringe, comprising a stopper body (1), characterized in that: The plug body (1) includes a first end and a second end; the first end is provided with a conical sealing head (2); the outer side wall of the second end is provided with a sealing boss (3); a plurality of convex rings (4) are provided between the conical sealing head (2) and the sealing boss (3); the plurality of convex rings (4) are provided on the outer wall of the plug body (1); the sealing boss (3) includes a contraction part and an expansion part; the contraction part is provided at the bottom opening of the plug body (1); the expansion part is provided at one end of the plug body (1) near the convex ring (4); the expansion part has a groove opening towards the convex ring (4).

2. The piston for a pre-filled syringe according to claim 1, characterized in that: The side wall of the convex ring (4) away from the plug (1) is an arc-shaped side wall; the outer groove wall of the groove away from the plug (1) and the top edge of the arc-shaped side wall are on the same vertical line.

3. The piston for a pre-filled syringe according to claim 1, characterized in that: The groove cavity is provided with a flow guide (5).

4. The piston for a pre-filled syringe according to any one of claims 1-3, characterized in that: The plug body (1) has a convex cavity (11) inside; the top of the convex cavity (11) extends toward the conical sealing head (2); the bottom of the convex cavity (11) is connected to the opening at the bottom of the plug body (1).

5. The piston for a pre-filled syringe according to claim 4, characterized in that: The bottom of the plug (1) is provided with multiple limiting components (6).

6. The piston for a pre-filled syringe according to claim 5, characterized in that: The limiting component (6) includes an elastic protrusion (61) and a hemisphere (62); one end of the elastic protrusion (61) is connected to the inner wall of the plug (1); the hemisphere (62) is located at the end of the elastic protrusion (61) away from the plug (1).

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