Piston rod and medicine tube of disposable needleless injector and needleless injector thereof

Abstract

The utility model belongs to the technical field of syringes, and particularly relates to a disposable needleless syringe piston rod, a medicine tube and a needleless syringe, the piston rod comprises a rod body formed by extending in the axial direction, the front end of the rod body in the axial direction is an installation part used for installing a piston, and the rear end of the rod body protrudes in the radial direction to form a flange; a rigid protrusion used for abutting against the injection tube body is arranged at the front end of the flange, and when the rigid protrusion abuts against the rear end face of the injection tube body, a safety distance L exists between the front end of the piston and the front end of the injection tube body. When the rigid protrusion on the flange abuts against the rear end of the injection tube body, the front end of the piston does not make contact with the front end of the injection tube body, the situation that the front end of the injection tube body is broken due to impact can be avoided, and the service life of the injector is prolonged.

Description

Technical Field

[0001] The utility model belongs to the technical field of syringes, and particularly relates to a piston rod, a medicine tube of a disposable needleless syringe and the needleless syringe. Background Art

[0002] A needleless syringe is usually used for subcutaneous injection of insulin. It includes an injection tube body, a piston rod sliding inside it, and a pressing mechanism for pushing the piston rod. During injection, the pressing mechanism pushes the piston rod, and the piston rod forms a high-speed jet of the liquid medicine in the injection tube body and sprays it into the body.

[0003] In the prior art, when the piston rod pushes out the liquid medicine, the pressing mechanism pushes the piston rod until it abuts against the head of the injection tube body. The collision between the high-speed moving piston rod and the head of the injection tube body will cause the injection tube body to rupture, resulting in the failure of the pressure of the liquid medicine during liquid discharge, and the liquid medicine cannot be injected into the body, thus leading to the failure of liquid injection. Summary of the Utility Model

[0004] The technical problem to be solved by the utility model is: to solve the problem that in the prior art, when the piston rod pushes out the liquid medicine, the pressing mechanism pushes the piston rod until it abuts against the head of the injection tube body, and the collision between the high-speed moving piston rod and the head of the injection tube body will cause the injection tube body to rupture, resulting in the failure of the pressure of the liquid medicine during liquid discharge, and the liquid medicine cannot be injected into the body, thus leading to the failure of liquid injection. Now, a piston rod, a medicine tube of a disposable needleless syringe and the needleless syringe are provided.

[0005] The technical solution adopted by the utility model to solve its technical problem is: a piston rod of a disposable needleless syringe, which is used in cooperation with the injection tube body of the needleless syringe to push out the liquid medicine in the injection tube body. The piston rod includes a rod body formed by extending axially. The front end of the rod body along its axis is an installation part for installing a piston. The rear end of the rod body protrudes radially to form a flange. A rigid protrusion for abutting against the injection tube body is provided at the front end of the flange. When the rigid protrusion abuts against the rear end face of the injection tube body, there is a safety distance L between the front end of the piston and the front end of the injection tube body.

[0006] Furthermore, there are several rigid protrusions, and the several rigid protrusions are spaced apart circumferentially along the flange.

[0007] Furthermore, the rigid protrusion is of a hemispherical structure.

[0008] Furthermore, a connecting piece is axially extended from the rear end of the flange, and the connecting piece is used for connecting with the pressing mechanism of the needleless syringe.

[0009] Furthermore, the connecting piece includes a rod part connected with the flange and a hook part bent inward from the rear end of the rod part.

[0010] Further, there are several of the connecting members, and the several connecting members are circumferentially spaced along the flange.

[0011] Further, the several rod portions among the several connecting members gradually approach each other from front to back.

[0012] Further, several grooves are circumferentially formed on the outer peripheral wall of the rod body, and each groove extends along the axial direction of the rod body.

[0013] A needleless syringe medicine tube includes an injection tube body having an inner cavity, and a nozzle communicating with the inner cavity is provided at the front end of the injection tube body. The piston rod is slidably installed in the inner cavity, and a piston is clamped on the installation portion of the piston rod.

[0014] A needleless syringe includes the above-mentioned needleless syringe medicine tube.

[0015] The beneficial effect of the present utility model is that when the rigid protrusion on the flange abuts against the rear end of the injection tube body, the front end of the piston has not yet contacted the front end of the injection tube body, which can avoid the situation that the front end of the injection tube body is impacted and broken, and improves the service life of the syringe.

[0016] Other features and advantages of the present application will become clear through the following detailed description of the exemplary embodiments of the present application with reference to the accompanying drawings. Description of the Drawings

[0017] The present utility model will be further described below in conjunction with the drawings and embodiments.

[0018] Figure 1 is a schematic structural view of the piston rod;

[0019] Figure 2 is a schematic structural view of a needleless syringe having two connecting members;

[0020] Figure 3 is Figure 2 a cross-sectional view taken along the A-A direction in;

[0021] Figure 4 is a schematic structural view of a needleless syringe having four connecting members;

[0022] In the figure:

[0023] 1. Injection tube body; 101. Nozzle; 102. Conical section; 103. Cylindrical section;

[0024] 2. Piston rod; 201. Flange; 2011. Rigid protrusion; 202. Connecting member; 2021. Rod portion; 2022. Hook portion; 203. Groove; 204. Rod body; 205. Installation portion;

[0025] 3. Piston; 301. Cylindrical part; 302. Conical part. Detailed implementation manners

[0026] The present utility model will be further described in detail below with reference to the accompanying drawings. These drawings are all simplified schematic diagrams, only schematically showing the basic structure of the present utility model, so they only show the components related to the present utility model. Directions and references (such as up, down, left, right, etc.) can only be used to assist in the description of the features in the drawings. Therefore, the following specific implementation manners are not adopted in a restrictive sense, and the scope of the claimed subject matter is only defined by the appended claims and their equivalent forms.

[0027] As Figures 1 - 4 shown, the piston rod of the disposable needleless syringe is used in cooperation with the injection tube body 1 of the needleless syringe to push out the liquid medicine in the injection tube body 1. The piston rod includes a rod body 204 formed by extending axially. The rod body 204 is generally in a cylindrical structure. The front end of the rod body 204 in the axial direction is an installation part 205 for installing the piston 3. The rear end of the piston rod 2 extends out of the injection tube body 1 and protrudes radially to form a flange 201. A rigid protrusion 2011 for abutting against the injection tube body 1 is provided at the front end of the flange 201. When the rigid protrusion 2011 abuts against the rear end face of the injection tube body 1, there is a safety distance L between the front end of the piston 3 and the front end of the injection tube body 1; the rear end of the injection tube body 1 has a larger thickness and a long axial extension length, and it has a large structural strength, while the front end is a thin-wall structure compared with the rear end and has a smaller structural strength. The piston rod 2 moves forward at a high speed under the action of the pushing mechanism. When the rigid protrusion 2011 abuts against the rear end of the injection tube body 1, at this time, the piston rod 2 does not contact the front end of the injection tube body 1, which can avoid hitting the front end of the injection tube body 1 and causing it to break. Although the high-strength rear end collides with the rigid protrusion 2011, it is not easily damaged due to its own strength, and even if there is a little breakage, it will not affect the high-speed ejection of the liquid medicine, thereby improving the service life of the syringe.

[0028] In some examples, there are several rigid protrusions 2011, and the several rigid protrusions 2011 are circumferentially spaced apart along the flange 201. The number of the rigid protrusions 2011 is not limited in this embodiment and can be two, three, four, etc. When the spaced-apart rigid protrusions 2011 abut against the flange 201, the flange 201 can be evenly stressed, thereby improving the service life of the flange 201.

[0029] In some examples, the rigid protrusion 2011 is in a hemispherical structure. Of course, it can also be in a cylindrical structure, etc. It only needs to satisfy protruding from the front end face of the flange 201, and the rigid protrusion 2011 is integrally formed with the flange 201, thereby improving the structural strength of the rigid protrusion 2011.

[0030] In some examples, a connecting member 202 is formed by axially extending the rear end of the flange 201. The connecting member 202 is used to connect with the pressing mechanism of the needleless syringe. The pressing mechanism drives the piston rod 2 to move forward at high speed through the connecting member 202.

[0031] In some examples, the connecting member 202 includes a rod portion 2021 connected to the flange 201 and a hook portion 2022 bent inward from the rear end of the rod portion 2021. The hook connection with the pressing mechanism can be achieved through the hook portion 2022.

[0032] In some examples, there are several connecting members 202, and the several connecting members 202 are circumferentially spaced along the flange 201. The number of the connecting members 202 can be two, three, four, etc. This embodiment does not limit this. The circumferentially spaced connecting members 202 can improve the connection strength between it and the pressing mechanism.

[0033] In some examples, the several rod portions 2021 among the several connecting members 202 gradually approach each other from front to back, that is, the rod portions 2021 are in an inclined state. When the hook portion 2022 is hooked to the pressing mechanism, the several inclined rod portions 2021 wrap the pressing mechanism, thereby improving the connection strength between the piston rod 2 and the pressing mechanism.

[0034] In some examples, a plurality of grooves 203 are circumferentially formed on the outer peripheral wall of the rod body 204, and each groove 203 extends axially along the rod body 204. The extension length is less than the length of the rod body 204, that is, the front and rear ends of the groove 203 do not penetrate the end face of the rod body 204. The cross section of the groove 203 can be arc-shaped, square, trapezoidal, etc. This embodiment does not limit this. It only needs to satisfy the formation of a depression to reduce the contact area with the injection tube body 1, thereby reducing the thrust applied by the pressing mechanism to the piston rod 2.

[0035] In some examples, a needleless syringe cartridge includes an injection tube body 1 having an inner cavity. The inner cavity includes a tapered section 102 at the front end and a cylindrical section 103 at the rear end. A nozzle 101 communicating with the inner cavity is provided on the tapered section 102. The piston rod 2 is slidably installed in the inner cavity, and a piston 3 is clamped on the installation portion 205 of the piston rod 2. Correspondingly, the piston 3 includes a cylindrical portion 301 matching the cylindrical section 103 of the inner cavity and a tapered portion 302 matching the tapered section 102 of the inner cavity. The cylindrical portion 301 of the piston 3 is snap-connected to the piston rod 2. An annular groove is provided on the installation portion 205, and a receiving groove for receiving the piston rod 2 is provided at the rear end of the cylindrical portion 301. The notch of the receiving groove contracts radially to form a constriction, and the constriction is snapped into the annular groove to realize the connection between the piston rod 2 and the piston 3. A liquid storage cavity for storing the liquid medicine is formed by enclosing the piston 3 and the inner cavity wall. The piston 3 pushes the liquid medicine in the liquid storage cavity forward under the action of the piston rod 2. When the liquid medicine reaches the tapered section 103, the cross-sectional area of the liquid storage cavity decreases sharply, the flow rate of the liquid medicine increases, and the liquid medicine sprays out from the nozzle 101 at the front end of the injection tube body 1.

[0036] In some examples, a needleless syringe includes the above-mentioned needleless syringe cartridge.

[0037] Based on the ideal embodiments of the present invention as inspiration, through the above description, relevant staff can completely make various changes and modifications without departing from the technical idea of this invention. The technical scope of this invention is not limited to the content in the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A disposable needle-free syringe piston rod, which is used in conjunction with an injection tube body (1) of the needle-free syringe to push out a liquid medicine in the injection tube body (1), characterized in that: The piston rod (2) comprises a rod body (204) extending in the axial direction, the front end of the rod body (204) in the axial direction is a mounting portion (205) for mounting the piston (3), the rear end protrudes in the radial direction to form a flange (201), the front end of the flange (201) is provided with a rigid protrusion (2011) for abutting against the injection tube body (1), when the rigid protrusion (2011) abuts against the rear end surface of the injection tube body (1), the front end of the piston (3) and the front end of the injection tube body (1) have a safety distance L.

2. The disposable needle-free syringe piston rod according to claim 1, characterized in that: There are a plurality of rigid protrusions (2011), and the rigid protrusions (2011) are distributed at intervals along the circumference of the flange (201).

3. The disposable needle-free syringe piston rod according to claim 1, characterized in that: The rigid protrusion (2011) is a hemispherical structure.

4. The disposable needle-free syringe piston rod according to claim 1, characterized in that: A connecting piece (202) is formed at the rear end of the flange (201) along its axial direction, and the connecting piece (202) is used to be connected to a pushing mechanism of a needle-free syringe.

5. The disposable needle-free syringe piston rod according to claim 4, characterized in that: The connecting member (202) comprises a rod portion (2021) connected to the flange (201) and a hook portion (2022) bent inward from the rear end of the rod portion (2021).

6. The disposable needle-free syringe piston rod according to claim 4, characterized in that: There are a plurality of connecting pieces (202), and the connecting pieces (202) are distributed at intervals along the circumference of the flange (201).

7. The disposable needle-free syringe piston rod according to claim 5, characterized in that: The plurality of rod portions (2021) in the plurality of connecting members (202) gradually move closer together from front to back.

8. The disposable needle-free syringe piston rod according to claim 1, characterized in that: The outer peripheral wall of the rod body (204) is provided with a plurality of grooves (203) along its circumference, and each groove (203) extends axially along the rod body (204).

9. A needle-free syringe cartridge, characterized in that: The invention comprises an injection tube body (1) having an inner cavity, wherein the front end of the injection tube body (1) has a nozzle (101) connected to the inner cavity, wherein a piston rod (2) as claimed in any one of claims 1 to 8 is slidably installed in the inner cavity, and a piston (3) is clamped on the mounting portion (205) of the piston rod (2).

10. A needle-free syringe, characterized in that: Comprising the needle-free syringe cartridge as claimed in claim 9.

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