CN115227913B

CN115227913B - Automatic injector and injection syringe thereof

Info

Publication number: CN115227913B
Application number: CN202210882880.4A
Authority: CN
Inventors: 朱元浩; 金开锋; 刘海燕
Original assignee: Nanjing Kaidi Medical Technology Co ltd
Current assignee: Nanjing Kaidi Medical Technology Co ltd
Priority date: 2022-07-26
Filing date: 2022-07-26
Publication date: 2023-10-20
Anticipated expiration: 2042-07-26
Also published as: CN115227913A

Abstract

The invention relates to an automatic injector and an injection syringe thereof. The outer cylinder assembly is sleeved outside the needle cylinder body and is in sliding connection with the needle cylinder body, and a first elastic piece is arranged on the side wall of the outer cylinder assembly. The second elastic piece is sleeved on the needle cylinder body, one end of the second elastic piece is abutted with the outer cylinder assembly, and the other end of the second elastic piece is abutted with the flanging of the needle cylinder body. The first clamping piece is in sliding connection with the side wall of the outer cylinder assembly along the first direction, one end of the second clamping piece is in sliding connection with the side wall of the outer cylinder assembly along the first direction, the other end of the second clamping piece is connected with the flanging of the syringe body, after the injection of the injection syringe is completed, the first elastic piece, the first clamping piece and the second clamping piece are in a complete clamping state along the first direction, namely, the outer cylinder assembly and the syringe body cannot generate relative movement, and a needle at the end part of the syringe body cannot extend out of the outer cylinder assembly, so that the syringe body can be prevented from being accidentally injured again due to the exposure of the needle.

Description

Automatic injector and injection syringe thereof

Technical Field

The invention relates to the technical field of automatic injectors, in particular to an automatic injector and an injection needle cylinder thereof.

Background

Autoinjectors include disposable autoinjectors and reusable autoinjectors, wherein a reusable autoinjector generally comprises a reusable injection holder and a syringe that is disposable. When injection is performed, only the disposable syringe is connected to the injection holder.

The existing disposable syringe generally comprises a syringe body, a needle arranged on one side of the syringe body and an outer barrel sleeved outside the syringe body, and before use, the outer barrel can cover the needle to protect the needle. In addition, the outer barrel can move along the axial direction of the syringe body, so that the needle head can be exposed out of the outer barrel to be inserted into the machine body when in use.

However, after the disposable needle cylinder is used, the outer cylinder can still move along the axial direction of the needle cylinder body, so that the risk of accidental injury of the body again due to the exposed needle head exists after the injection is finished.

Disclosure of Invention

In view of this, it is necessary to provide an automatic injector and a syringe thereof, which are directed to the problem that there is a risk of accidental injury of the body again due to exposure of the needle after the injection is completed.

An injection syringe, comprising:

a syringe body;

the needle head is arranged at one end of the syringe body along a first direction, and the first direction is along the length direction of the syringe body;

the outer cylinder assembly is sleeved outside the needle cylinder body and is in sliding connection with the needle cylinder body, and a first elastic piece is arranged on the side wall of the outer cylinder assembly;

the second elastic piece is sleeved on the needle cylinder body, one end of the second elastic piece is in butt joint with the outer cylinder assembly, and the other end of the second elastic piece is in butt joint with the flanging of the needle cylinder body;

the first clamping piece is in sliding connection with the side wall of the outer cylinder assembly along a first direction and is provided with a first sliding position and a second sliding position;

one end of the second clamping piece is connected with the side wall of the outer cylinder assembly in a sliding manner along a first direction, the other end of the second clamping piece is connected with the flanging of the needle cylinder body, and the second clamping piece is provided with a first clamping position and a second clamping position;

the injection syringe has a first state, a second state, and a third state;

when the injection needle cylinder is in a first state, the needle head is positioned in the outer cylinder assembly, the first clamping piece is positioned at a first sliding position, the first clamping piece locks the first elastic piece, the second clamping piece is positioned at a first clamping position, and the second clamping piece can be close to the first clamping piece;

when the syringe body and the outer cylinder assembly slide relatively and the needle extends out of the outer cylinder assembly, the syringe is switched from a first state to a second state, when the syringe is in the second state, the second elastic piece is in a force storage state, the second clamping piece is in a second clamping position and is clamped with the first clamping piece in a first sliding position, and meanwhile, the first clamping piece locks the first elastic piece;

when the second elastic piece is converted from a force storage state to a release state, the injection syringe is in a third state, the needle is retracted into the outer cylinder assembly, the second clamping piece is clamped with the first clamping piece at a first clamping position, the first clamping piece is in a second sliding position, the second clamping piece releases the first elastic piece, and the first elastic piece is used for being abutted with the first clamping piece along a first direction.

In one embodiment, the first elastic member is a spring block, one end of the first elastic member along the forward direction of the first direction is connected with the side wall of the outer cylinder assembly, and the outer wall of the first elastic member extends in a direction away from the axis of the syringe body along the direction from the forward direction to the reverse direction of the first direction;

when the first clamping piece is at the first sliding position, the outer wall of the first elastic piece is abutted with the inner wall of the first clamping piece;

when the first clamping piece is at the second sliding position, the end part of the first elastic piece in the forward direction along the first direction is abutted with the first clamping piece;

wherein the first direction forward direction refers to the injection direction from the injection syringe, and the first direction reverse direction is opposite to the first direction forward direction.

In one embodiment, a sliding groove matched with the first elastic piece is formed in the inner wall of the first clamping piece.

In one embodiment, the first clamping piece is provided with a clamping groove with an opening direction facing the reverse direction of the first direction, one end of the second clamping piece along the forward direction of the first direction is provided with a clamping hook component, and the clamping hook component is used for being clamped with the clamping groove.

In one embodiment, the hook component includes two hooks, one ends of the two hooks along the reverse direction of the first direction are connected with each other, one ends of the two hooks along the forward direction of the first direction are arranged at intervals, the hooks are provided with hook parts, and the hook parts of the two hooks are away from each other;

the clamping groove comprises a shrinkage section and a hooking section which are sequentially connected, the hooking section is positioned at one end of the shrinkage section along the forward direction of the first direction, the opening size of the shrinkage section is smaller than that of the hooking section, a stepped hooking surface is formed at the connection position of the shrinkage section and the hooking section, and the hooking surface is used for hooking with the hook part.

In one embodiment, the end of the contraction section away from the hooking section is provided with a flaring part, and the flaring part is matched with the integral shape formed by the two hooking parts.

In one embodiment, the outer cylinder assembly is provided with a sliding hole, and the inner wall of the second clamping piece is provided with a sliding block, and the sliding block is used for sliding in the sliding hole.

In one embodiment, the outer cylinder assembly comprises a first cylinder and a second cylinder, the first cylinder is sleeved outside the second cylinder and is in clamping connection with the second cylinder, the second elastic piece is in abutting connection with the second cylinder, and one end of the first cylinder, which is opposite to the first direction, extends out of the syringe body and is used for being in abutting connection with the injection retainer.

In one embodiment, an end of the first cylinder extending out of the syringe body is provided with an inward folded edge, the folded edge is provided with a first step surface and a second step surface which are gradually increased, when the injection syringe is in a first state, the folded edge of the syringe body is abutted with the first step surface, and the second step surface is used for hooking with a frame body of the injection retainer.

In one embodiment, the injection syringe further comprises a protective needle cover, the protective needle cover comprises a first protective cover sleeved on the outer cylinder component and a second protective cover sleeved on the needle, the first protective cover is provided with an outer wall and an inner wall, one end of the outer wall is connected with the inner wall, the outer cylinder component is inserted between the outer wall and the inner wall, and the inner wall is sleeved outside the second protective cover and is connected with the second protective cover.

An automatic injector includes an injection holder and an injection syringe, the injection holder being disposed at an end of the syringe body remote from the needle.

The automatic injector and the injection syringe thereof can enable the injection syringe to be in a complete clamping state in the first direction after injection is completed through the arrangement of the syringe body, the outer cylinder assembly, the second elastic piece, the first clamping piece and the second clamping piece, and one end of the second clamping piece is connected with the syringe body due to the fact that the first elastic piece is arranged on the outer cylinder assembly, namely, relative movement cannot be generated between the outer cylinder assembly and the syringe body, so that a needle at the end of the syringe body cannot extend out of the outer cylinder assembly again, and the needle can be prevented from being exposed out of the syringe body to injure a syringe body by mistake again.

Drawings

FIG. 1 is an exploded view of an injection syringe in one embodiment;

fig. 2 is a schematic view of the structure of the syringe barrel prior to injection;

FIG. 3 is a schematic view of the internal structure of FIG. 2;

FIG. 4 is a schematic view of the structure of the syringe during injection;

fig. 5 is a schematic view of the structure of the syringe after injection.

Reference numerals:

100-syringe body; 110-flanging;

200-needle head;

300-an outer barrel assembly; 310-a first elastic member; 320-a first cylinder; 321-a first step surface; 322-second step surface; 330-a second cylinder; 331-slide hole;

400-a second elastic member;

600-first clamping piece; 610-chute; 620-a clamping groove; 621-a shrink section; 6211-flared portions; 622-hooking section; 623-hook interface;

700-second clamping piece; 710-a catch assembly; 711-clamping hook; 7111-hook; 720-sliders;

800-protecting the needle shield; 810-a first protective cover; 811-an outer wall; 812-inner wall; 820-a second protective cover; 900-plugging a soft plug; 910-stopper cap; 920-occlusion segment.

Detailed Description

In order that the above objects, features and advantages of the invention will be readily understood, a more particular description of the invention will be rendered by reference to the appended drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The present invention may be embodied in many other forms than described herein and similarly modified by those skilled in the art without departing from the spirit of the invention, whereby the invention is not limited to the specific embodiments disclosed below.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present invention.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present invention, unless expressly stated or limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.

It will be understood that when an element is referred to as being "fixed" or "disposed" on another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like are used herein for illustrative purposes only and are not meant to be the only embodiment.

Referring to fig. 1-5, an embodiment of the present invention provides an injection syringe, which includes a syringe body 100, a needle 200, an outer barrel assembly 300, a second elastic member 400, a first locking member 600 and a second locking member 700. The needle 200 is disposed at one end of the syringe body 100 along a first direction, which is a length direction of the syringe body 100. The outer cylinder assembly 300 is sleeved outside the syringe body 100 and is slidably connected with the syringe body 100, and a first elastic member 310 is disposed on a side wall of the outer cylinder assembly 300. The second elastic member 400 is sleeved on the syringe body 100, and has one end abutting against the outer cylinder assembly 300 and the other end abutting against the flange 110 of the syringe body 100. The first clamping piece 600 is slidably connected with the side wall of the outer cylinder assembly 300 along the first direction, and the first clamping piece 600 has a first sliding position and a second sliding position. One end of the second clamping member 700 is slidably connected with the side wall of the outer cylinder assembly 300 along the first direction, and the other end of the second clamping member 700 is connected with the flange 110 of the syringe body 100, and the second clamping member 700 has a first clamping position and a second clamping position. The syringe has a first state, a second state, and a third state. When the syringe is in the first state, the needle 200 is located in the outer barrel assembly 300, the first clamping member 600 is located in the first sliding position, the first clamping member 600 locks the first elastic member 310, the second clamping member 700 is located in the first clamping position, and the second clamping member 700 can approach the first clamping member 600. When the syringe body 100 and the outer barrel assembly 300 slide relatively and the needle 200 extends out of the outer barrel assembly 300, the syringe is switched from the first state to the second state, and when the syringe is in the second state, the second elastic member 400 is in the force storage state, the second clamping member 700 is in the second clamping position and is clamped with the first clamping member 600 in the first sliding position, and meanwhile, the first clamping member 600 locks the first elastic member 310. When the second elastic member 400 is switched from the power storage state to the release state, the syringe is in the third state, the second clamping member 700 is clamped with the first clamping member 600 at the first clamping position, the first clamping member 600 is in the second sliding position, the second clamping member 700 releases the first elastic member, and the first elastic member is used for abutting against the first clamping member 600.

When the device is specifically used, the first state, the second state and the third state are respectively the state of the injection needle cylinder before injection, the state of the injection needle cylinder during injection and the state of the injection needle cylinder after injection. The first clamping member 600 has a first sliding position and a second sliding position, wherein the first sliding position is located at one side of the second sliding position along the first direction OA. The second clamping member 700 has a first clamping position and a second clamping position, wherein the first clamping position is located at one side of the second clamping position near the opposite OB direction of the first direction. Wherein the first direction forward direction OA refers to an injection direction from the injection syringe, and the first direction reverse OB is opposite to the first direction forward direction OA.

With reference to fig. 2, before injection, i.e., the syringe is in the first state, i.e., the syringe is not stressed, at this time, the second elastic member 400 is in the released state, and the second elastic member 400 is disposed between the outer cylinder assembly 300 and the flange 110 of the syringe body 100. The first clamping member 600 is located at the first sliding position and locks the first elastic member 310, and the second clamping member 700 is located at the first clamping position, so that no clamping effect exists between the first clamping member 600 and the second clamping member 700.

Referring to fig. 4, when injection is required, i.e., the injection syringe is in the second state, one end of the outer cylinder assembly 300 is abutted against the body and the syringe body 100 is pressed downward, and the needle 200 at the end of the syringe body 100 is moved toward the body with respect to the outer cylinder assembly 300 to be inserted into the body. When the syringe body 100 moves toward the machine body, the syringe body 100 compresses the second elastic member 400, so that the second elastic member 400 is in a force storage state, and meanwhile, the second clamping member 700 moves from the first clamping position to the second clamping position and can be clamped with the first clamping member 600 at the second clamping position.

Referring to fig. 5, when the injection is completed, i.e., the syringe is in the third state, the needle 200 is pulled out of the body through the syringe body 100, and at this time, the second elastic member 400 is converted into the release state due to the pushing action of the inorganic body on the outer cylinder assembly 300 and the elastic force of the second elastic member 400 itself. At this time, the second clamping member 700 drives the first clamping member 600 to return to the first clamping position again, i.e. the first clamping member 600 moves from the first sliding position to the second sliding position. After the second clamping member 700 moves, the second clamping member 700 releases the first elastic member 310, and the released first elastic member 310 abuts against an end of the first clamping member 600 away from the second clamping member 700. Namely, the first elastic member, the first locking member 600 and the second locking member 700 are in a completely locked state in the first direction, and since the first elastic member is disposed on the outer cylinder assembly 300, one end of the second locking member 700 is connected with the syringe body 100, thereby being capable of preventing a relative movement between the outer cylinder assembly 300 and the syringe body 100.

That is, by the arrangement of the syringe body 100, the outer barrel assembly 300, the second elastic member 400, the first clamping member 600 and the second clamping member 700, the syringe body 100 and the outer barrel assembly 300 cannot generate relative movement after injection, i.e. the needle 200 at the end of the syringe body 100 cannot extend out of the outer barrel assembly 300 again, thereby preventing the needle 200 from being exposed to injure the body again.

In some embodiments, the first elastic member 310 is a spring block, one end of the first elastic member 310 along the first direction forward direction OA is connected to the side wall of the outer cylinder assembly 300, and the outer wall of the first elastic member extends away from the axis of the syringe body 100 along the direction from the first direction forward direction OA to the first direction reverse OB. When the first locking member 600 is at the first sliding position, the outer wall of the first elastic member 310 abuts against the inner wall of the first locking member 600. When the first locking member 600 is at the second sliding position, the end of the first elastic member along the first direction forward direction OA is in contact with the first locking member 600.

In this embodiment, since the outer wall of the first elastic member extends in a direction away from the axis of the syringe along the direction from the first direction forward OA to the first direction backward OB, that is, when the first locking member 600 slides from the first sliding position to the second sliding position, the first locking member 600 can gradually press the first elastic member 310, so that the first locking member 600 can slide from the first sliding position to the second sliding position. When the first locking member 600 is at the first sliding position, the first locking member 600 is located outside the first elastic member 310, and the first elastic member 310 is in a locked state. When the first locking element 600 is at the second sliding position, the first locking element 600 moves to one side of the first elastic element 310 along the direction OB in the first direction, that is, the first locking element 600 releases the first elastic element 310, and since the direction from the forward direction OA to the reverse direction OB in the first direction is along the direction away from the axis of the syringe, that is, after the first elastic element 310 is released, one end of the first elastic element 310 along the reverse direction OB in the first direction can limit the first locking element 600 along the forward direction OA, so as to prevent the first locking element 600 from moving to one side of the forward direction OA in the first direction.

Further, referring to fig. 1, a sliding groove 610 matching the first elastic member 310 is formed on the inner wall of the first clamping member 600. Specifically, since the outer wall of the first elastic member extends in a direction away from the axis of the syringe along the direction from the first direction forward OA to the first direction backward OB, the depth of the chute 610 is also sequentially deepened along the direction from the first direction forward OA to the first direction backward OB, that is, the first elastic member is not pressed when the first clamping member 600 is in the first sliding position, and the first elastic member is pressed only when the first clamping member 600 is moved from the first sliding position to the second sliding position, which is favorable for maintaining the elastic force of the first elastic member and increasing the service life of the first elastic member.

In some embodiments, referring to fig. 1 and 2, the first clamping member 600 is provided with a clamping groove 620 with an opening direction facing the reverse direction OB of the first direction, and one end of the second clamping member 700 along the forward direction OA is provided with a hook component 710, that is, when the second clamping member 700 moves from the first clamping position to the second clamping position, the hook component 710 can be inserted into the clamping groove 620 from the opening position of the clamping groove 620, so as to be clamped with the clamping groove 620.

Further, the hook component 710 includes two hooks 711, wherein one ends of the two hooks 711 along the first direction opposite to OB are connected to each other, the two hooks 711 are disposed at intervals along one end of the first direction forward to OA, the hooks 711 have hook portions 7111, and the hook portions 7111 of the two hooks 711 are away from each other. The clamping groove 620 includes a shrinkage section 621 and a hooking section 622 connected in sequence, the hooking section 622 is located at one end of the shrinkage section 621 along the forward direction OA, the opening size of the shrinkage section 621 is smaller than that of the hooking section 622, so as to form a stepped hooking surface 623 at the connection position of the shrinkage section 621 and the hooking section 622, and the hooking surface 623 is used for hooking with the hook 7111.

In this embodiment, when the hook component 710 extends into the clamping groove 620, since one ends of the two hooks 711 are spaced apart, when the two hooks 711 extend into the shrinkage section 621, the shrinkage section 621 can press the two hooks 711 inwards, so that the two hooks 711 are close to each other. When the hooks 711 extend into the hooking sections 622, the hooking portions 7111 of the two hooks 711 are released at the hooking sections 622, and the hooking portions 7111 are hooked with the hooking surface 623, so that the hooking of the second clamping member 700 and the first clamping member 600 can be completed.

Specifically, the end of the shrinkage segment 621 remote from the hooking segment 622 has a flared portion 6211, and the flared portion 6211 is adapted to the overall shape formed by the two hooks 7111. The provision of flared portions 6211 facilitates the protrusion of hook portion 7111 into constriction 621.

In some embodiments, referring to fig. 1, the outer cylinder assembly 300 is provided with a sliding hole 331, and the inner wall of the second clamping member 700 is provided with a sliding block 720, where the sliding block 720 is used to slide in the sliding hole 331, so that stability of the second clamping member 700 when sliding on the outer cylinder assembly 300 can be increased.

In some embodiments, referring to fig. 3, the outer barrel assembly 300 includes a first barrel 320 and a second barrel 330, the first barrel 320 is sleeved outside the second barrel 330 and is engaged with the second barrel 330, the second elastic member 400 abuts against the second barrel 330, and one end of the first barrel 320 in the direction opposite OB extends outside the syringe body 100 and is used for interfacing with an injection holder.

In this embodiment, since the first cylinder 320 is engaged with the second cylinder 330, when the first cylinder 320 abuts against the body during injection, the first cylinder 320 and the second cylinder 330 are simultaneously kept stationary, and the syringe body 100 moves toward the body side in the first cylinder 320, so that the frame of the injection holder is conveniently inserted into the first cylinder 320 and is conveniently connected with the first cylinder 320.

Further, the end of the first cylinder 320 extending to the outside of the syringe body 100 has an inwardly turned flange having a first stepped surface 321 and a second stepped surface 322 which are sequentially increased. When the syringe is in the first state, the flange 110 of the syringe body 100 abuts against the first stepped surface 321, that is, the acting force of the first cylinder 320 on the second cylinder 330 and the syringe body 100 respectively and the elastic force of the second elastic member 400 are balanced, so that the syringe is in a stable state before not being used. In addition, the second step surface 322 is configured to hook into the body of the syringe retainer when docked with the syringe retainer to effect connection of the syringe barrel to the syringe retainer.

In some embodiments, referring to fig. 1, the syringe further comprises a protective needle shield 800, the protective needle shield 800 comprising a first protective shield 810 sleeved over the outer barrel assembly 300 and a second protective shield 820 sleeved over the needle 200, the first protective shield 810 having an outer wall 811 and an inner wall 812 connected at one end, the outer barrel assembly 300 being adapted to be inserted between the outer wall 811 and the inner wall 812, the inner wall 812 being sleeved over the second protective shield 820 and connected to the second protective shield 820.

In use, first, the outer wall 811 of the outer barrel assembly 300 is held, i.e., the first protective cover 810 and the second protective cover 820 can be pulled out simultaneously.

In some embodiments, referring to fig. 1 and 3, the syringe barrel further comprises a stopper 900, the stopper 900 being used to block the end of the syringe body 100 remote from the needle 200. Specifically, the stopper 900 includes a stopper cap 910 and a stopper section 920, the stopper section 920 is configured to be inserted into the barrel of the syringe body 100, and the stopper cap 910 is configured to mate with the flange of the first barrel 320.

The technical features of the above embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The foregoing examples illustrate only a few embodiments of the invention, which are described in detail and are not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.

Claims

1. An injection syringe, comprising:

a syringe body;

the injection syringe has a first state, a second state, and a third state;

when the second elastic piece is converted from a force storage state to a release state, the injection syringe is in a third state, the needle is retracted into the outer cylinder assembly, the second clamping piece is clamped with the first clamping piece at a first clamping position, the first clamping piece is in a second sliding position, the second clamping piece releases the first elastic piece, and the first elastic piece is used for being abutted with the first clamping piece along a first direction, so that the needle at the end part of the syringe body cannot extend out of the outer cylinder assembly again.

2. The syringe of claim 1, wherein the first elastic member is a spring block, one end of the first elastic member in a forward direction is connected to the side wall of the outer barrel assembly, and an outer wall of the first elastic member extends in a direction away from the axis of the syringe body in a direction from the forward direction to the reverse direction;

3. The syringe of claim 2, wherein the inner wall of the first locking element is provided with a chute matching the first elastic element.

4. The syringe of claim 1, wherein the first engaging member is provided with an engaging groove having an opening direction opposite to the first direction, and the second engaging member is provided with a hook assembly at one end along the forward direction of the first direction, and the hook assembly is adapted to engage with the engaging groove.

5. The syringe of claim 4, wherein the hook assembly comprises two hooks, wherein one ends of the two hooks along the first direction are opposite to each other, one ends of the two hooks along the first direction are spaced apart, the hooks have hook portions, and the hook portions of the two hooks face away from each other;

6. The syringe of claim 5, wherein the end of the contractile segment remote from the hooking segment has a flared portion that matches the overall shape formed by the two hooks.

7. The syringe of claim 1, wherein the outer barrel assembly defines a sliding aperture, and wherein the second locking element defines a slider disposed on an inner wall thereof for sliding within the sliding aperture.

8. The syringe of claim 1, wherein the outer barrel assembly comprises a first barrel and a second barrel, the first barrel is sleeved outside the second barrel and is clamped with the second barrel, the second elastic piece is abutted with the second barrel, and one end of the first barrel, which is opposite to the first direction, extends outside the syringe body and is used for being abutted with an injection retainer.

9. The syringe of claim 8, wherein an end of the first barrel extending beyond the syringe body has an inwardly turned flange having sequentially increasing first and second stepped surfaces, the flange of the syringe body abutting the first stepped surface in a first state of the syringe, the second stepped surface for hooking with a frame of an injection holder.

10. The syringe of claim 1 further comprising a protective needle shield comprising a first protective shield sleeved on the outer barrel assembly and a second protective shield sleeved on the needle, the first protective shield having an outer wall and an inner wall connected at one end, the outer barrel assembly being adapted to be inserted between the outer wall and the inner wall, the inner wall being sleeved outside the second protective shield and connected to the second protective shield.

11. An autoinjector comprising an injection retainer and an injection syringe according to any one of claims 1 to 10, said injection retainer being disposed at an end of said syringe body remote from said needle.