Automatic injection device

Abstract

The utility model provides an automatic injection device. The automatic injection device comprises a medicine cylinder, a needle, a shell, a plunger rod, a first elastic piece, a first switch piece and an injection button. The needle is arranged at the far end of the medicine cylinder, the shell is connected to the medicine cylinder, and the plunger rod is used for driving liquid medicine in the medicine cylinder to the far end. The plunger rod comprises a rod body and a limiting piece arranged on the rod body, the rod body is sleeved with the shell, and the limiting piece abuts against the shell towards the far end; the first elastic piece applies elastic force towards the far end to the rod body; the first switch piece is arranged on the shell so as to be switched between an opening state and a closing state; the injection button is arranged on the shell; when the first switch piece is in a closed state, the injection button abuts against the first switch piece towards the far end; when the first switch piece is in the open state, the injection button avoids relative to the first switch piece and can move towards the far end under external force so as to drive the limiting piece to be separated from the shell. Through the arrangement, the problem that liquid medicine is injected in advance due to the fact that the injection button is mistakenly touched can be solved.

Description

[0001] Cross-references

[0002] This application claims priority to Chinese patent application No. 202323165479.8, entitled "Automatic Injection Device", filed on November 22, 2023, with the State Intellectual Property Office of the People's Republic of China, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application belongs to the field of medical device technology, and more specifically, relates to an automated injection device. Background Technology

[0004] In the medical industry, disposable injection devices are increasingly favored by patients and medical staff and are widely used in order to prevent cross-infection.

[0005] Currently, the general procedure for using disposable injection devices on the market is as follows: first, insert the needle of the injection device into the injection site, and then press the injection button to administer the disposable medication. However, when inserting the needle into the injection site, the injection button may be accidentally pressed due to unfamiliarity with the procedure, or the button may be triggered by the device falling, causing premature injection of the medication.

[0006] For example, when the injection device is used for injecting antibody drugs, weight-loss drugs, medications for diabetes, and cardiovascular diseases, the device is usually administered by the patient themselves. Since the patient is not a medical professional, there is a high risk of accidental activation due to unfamiliarity with the device or accidental triggering of the injection button during drop. This poses a risk of injecting the medication prematurely before the needle is properly inserted into the injection site. Furthermore, because the device is disposable, each injection renders the entire device unusable, resulting in significant economic waste. Utility Model Content

[0007] One of the objectives of this application is to provide an automatic injection device that addresses the technical problem in the prior art where accidental activation of the injection button on the injection device leads to premature injection of the medication.

[0008] To solve the above-mentioned technical problems, the technical solution adopted in the embodiments of this application is as follows:

[0009] An automatic injection device is provided, having an axial direction, with its two opposite ends along the axial direction being a proximal end and a distal end, respectively; the automatic injection device includes a cartridge and a needle disposed at the distal end of the cartridge, and further includes:

[0010] The outer casing is attached to the cartridge case;

[0011] a plunger rod for driving a liquid medicine in a cartridge to a distal end; the plunger rod comprises a rod body and a limiting member elastically movably arranged on the rod body, and a housing is arranged on the rod body; the limiting member is configured to abut against the housing to the distal end;

[0012] a first elastic member for applying an elastic force to the rod body to the distal end to drive the rod body to inject;

[0013] a first switch member movably arranged on the housing to switch between an open state and a closed state;

[0014] an injection button axially movably arranged on the housing; in the closed state of the first switch member, the injection button abuts against the first switch member to the distal end and is spaced apart from the limiting member; in the open state of the first switch member, the injection button is spaced apart from the first switch member and can move to the distal end under an external force to drive the limiting member to disengage from the housing.

[0015] In an embodiment, the automatic injection device further comprises a cap, the cap being configured to detachably cover the needle and to sterilize the needle.

[0016] In an embodiment, the cap comprises:

[0017] a cap body configured to at least partially cover the needle;

[0018] a sterilization device arranged on the cap body and configured to sterilize the needle when the cap body covers the needle;

[0019] a second switch member arranged on the cap body and electrically connected to the sterilization device and configured to at least control the sterilization device.

[0020] In an embodiment, the limiting member comprises a first elastic arm and a barb arranged on the first elastic arm, the first elastic arm is arranged on the rod body, and the barb is configured to hook the housing to the distal end and the injection button can press the barb;

[0021] and / or, the first elastic member comprises a spring arranged on the rod body, the spring is configured to abut against the housing to the distal end and the injection button can press the spring.

[0022] In an embodiment, the injection button and the housing are sleeved with each other, either of the injection button and the housing is provided with a sliding groove extending along an axial direction, and the other is provided with a first guide rail slidingly arranged in the sliding groove; the injection button is provided with a first pressing portion, and the first pressing portion and the limiting member are arranged opposite to each other along the axial direction.

[0023] In an embodiment, the housing comprises a housing body and a fixing member arranged in the housing body, the cartridge is fixed in the housing body, the fixing member is sleeved on the rod body, and the limiting member can abut against the fixing member to the distal end;

[0024] The injection button comprises a button body, a first annular portion arranged on the button body, and a first extrusion portion arranged in the first annular portion; the shell and the fixing member are provided with an annular groove, and the first annular portion is arranged in the annular groove in an axially movable manner; the first switch member is arranged on the shell and / or the fixing member in a rotatable manner about the axis, and can be alternatively rotated to an open state and a closed state, and at least a part of the first switch member is arranged in the annular groove;

[0025] In the closed state, the first annular portion abuts against the first switch member in the distal direction; in the open state, the first annular portion is spaced apart from the first switch member and can move in the distal direction; the first extrusion portion can extrude the limiting member in the distal direction to make the limiting member disengage from the fixing member.

[0026] In an embodiment, the first switch member comprises a limiting ring rotatably arranged in the annular groove and axially opposite to the first annular portion; either the limiting ring or the first annular portion is provided with a protrusion, and the other is provided with a spacing groove; in the open state, the protrusion is configured to be axially opposite to the spacing groove to allow the button body to move in the distal direction under an external force; in the closed state, the protrusion is configured to limit the first annular portion in the distal direction.

[0027] In an embodiment, the protrusion has an elastic hook configured to be clamped in the spacing groove after the first extrusion portion extrudes the limiting member.

[0028] In an embodiment, the automatic injection device further comprises a protective sleeve, the shell is sleeved on the cartridge, the protective sleeve is sleeved between the cartridge and the shell and can move in the axial direction to retract into the shell or extend out of the distal end of the shell; the proximal end of the protective sleeve has a second elastic arm, and the distal end of the first switch member has a third elastic arm; when the protective sleeve retracts into the shell, the third elastic arm is configured to extrude the second elastic arm during switching of the first switch member to the open state; when the protective sleeve extends out of the distal end of the shell, the third elastic arm is configured to abut against the second elastic arm in the distal direction in the open state.

[0029] In an embodiment, the automatic injection device further comprises a third elastic member for applying an elastic force in the distal direction to the protective sleeve to make the protective sleeve extend out of the distal end of the shell and cover the needle.

[0030] The automatic injection device provided by the embodiments has the following beneficial effects:

[0031] The automatic injection device provided in this application embodiment allows for the following steps: After the needle is vertically inserted into the injection site, the first switch is activated to the open state. Then, the injection button is pressed, causing it to move distally and drive a limiting member to detach from the housing. When the limiting member detaches, the rod moves distally under the elastic force of the first elastic member, driving the medication in the cartridge and completing the injection. Furthermore, by allowing the limiting member to detach from the housing and the rod to drive the medication in the cartridge distally under the elastic force of the first elastic member, the rod cannot move proximally again, rendering the automatic injection device unusable and achieving a single-use capability. During the process of the needle not being inserted into the injection site or being inserted into the injection site, the first switch can be kept in the closed state. In this case, the injection button pushes against the first switch distally, preventing the injection button from moving distally. This means the injection button cannot drive the limiting member to detach from the housing, preventing the rod from driving the medication in the cartridge. Even if the injection button is accidentally pressed, the injection cannot be performed. This design can solve the problem of the medicine being injected prematurely due to accidental activation of the injection button. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 A partial perspective view of the automatic injection device provided in the initial state according to an embodiment of this application;

[0034] Figure 2 for Figure 1 Exploded view;

[0035] Figure 3 for Figure 1 A sectional view;

[0036] Figure 4 for Figure 3 A magnified view of a portion of the image;

[0037] Figure 5 for Figure 1 A schematic diagram of the provided automatic injection device in the open state of the first switch element.

[0038] Figure 6 for Figure 5 A sectional view;

[0039] Figure 7 for Figure 6 A magnified view of a portion of the image;

[0040] Figure 8 for Figure 5 A schematic diagram of the provided automatic injection device after drug injection;

[0041] Figure 9 for Figure 8 A schematic diagram of the provided automated injection device after the needle has been removed;

[0042] Figure 10 for Figure 1 Partial illustration Figure 1 ;

[0043] Figure 11 A perspective view of the fixture of the automatic injection device provided in the embodiments of this application;

[0044] Figure 12 A perspective view of the first housing of the automatic injection device provided in an embodiment of this application;

[0045] Figure 13 A perspective view of the injection button of the automatic injection device provided in the embodiments of this application;

[0046] Figure 14 A perspective view of the plunger rod of the automatic injection device provided in the embodiments of this application;

[0047] Figure 15 A perspective view of the first switching element of the automatic injection device provided in the embodiments of this application;

[0048] Figure 16 for Figure 15 A three-dimensional schematic diagram of the first switch component in conjunction with the injection button;

[0049] Figure 17 for Figure 16 Enlarged view of point A in the middle;

[0050] Figure 18 for Figure 1 Partial illustration Figure 2 ;

[0051] Figure 19 for Figure 8 A partial three-dimensional schematic diagram of the automated injection device shown.

[0052] Figure 20 for Figure 9 A partial three-dimensional schematic diagram of the automated injection device shown.

[0053] Figure 21 A perspective view of the protective cover of the automatic injection device provided in the embodiments of this application;

[0054] Figure 22Fig. 1 is a perspective view of an automatic injection device according to an embodiment of the present application; Figure 9 Fig. 2 is a sectional view of the automatic injection device of Fig. 1;

[0055] Figure 23 Fig. 3 is a perspective view of an automatic injection device according to another embodiment of the present application;

[0056] Figure 24 Fig. 4 is a sectional view of the automatic injection device of Fig. 3; Figure 23

[0057] Fig. 5 is a sectional view of the automatic injection device of Fig. 3; Figure 25 Figure 24 Fig. 6 is a sectional view of the automatic injection device of Fig. 3;

[0058] Figure 26 Fig. 7 is a sectional view of the automatic injection device of Fig. 3; Figure 24 Fig. 8 is a sectional view of the automatic injection device of Fig. 3;

[0059] In the drawings, reference numerals:

[0060] 10 - housing; 101 - limiting groove; 102 - sliding groove; 103 - sliding slot; 104 - annular groove; 11 - shell; 111 - first shell; 112 - second shell; 1121 - protrusion; 113 - fixed shell; 114 - fourth limiting portion; 115 - second guide rail; 12 - fixing member; 121 - first limiting portion; 122 - sleeve shell; 123 - third annular portion; 20 - syringe; 21 - cartridge; 22 - needle; 23 - plunger rod; 2301 - first pressing surface; 231 - rod body; 232 - limiting member; 2321 - first elastic arm; 2322 - barb; 24 - needle cap; 30 - first elastic member; 40 - first switch member; 41 - limiting ring; 42 - protrusion; 421 - elastic hook; 43 - third elastic arm; 44 - third pressing portion; 45 - trigger portion; 46 - connecting portion; 50 - injection button; 501 - avoiding groove; 51 - first guide rail; 52 - second limiting portion; 53 - button body; 54 - first annular portion; 55 - first pressing portion; 5501 - second pressing surface; 56 - second annular portion; 60 - second elastic member; 70 - protective sleeve; 701 - guide groove; 71 - second elastic arm; 72 - second pressing portion; 73 - sleeve; 74 - third limiting portion; 80 - third elastic member; 90 - guide rod; 100 - cap; 110 - cap body; 1110 - base; 1120 - first cap; 11210 - buckle; 1130 - second cap; 11310 - groove; 120 - sterilization device; 130 - second switch member; Y1 - first axial direction; Y2 - second axial direction. DETAILED DESCRIPTION

[0061] ​Embodiments of the present application are described below in detail with reference to the accompanying drawings, examples of which are shown in the drawings, wherein the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below are exemplary and are intended to explain the present application, and are not to be understood as limiting the present application.

[0062] In the description of the present application, it is to be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0063] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified and limited, wherein two or more includes two.

[0064] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium, it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0065] The following is described in detail in combination with specific drawings and examples:

[0066] Please refer to Figure 1 The automatic injection device provided by the embodiments of the present application has an axial direction, and the opposite ends of the automatic injection device along the axial direction are respectively a proximal end and a distal end. The proximal end refers to the end of the automatic injection device away from the injection site during the injection process, and the distal end refers to the end of the automatic injection device close to the injection site during the injection process. The proximal end is, for example, Figure 1 indicated by reference numeral a, and the distal end is, for example, Figure 1The schematic reference b. The axial direction includes a first axial direction Y1 and a second axial direction Y2, both of which are parallel to the axial direction, and the directions of the first axial direction Y1 and the second axial direction Y2 are opposite. Hereinafter, "proximal" generally refers to the first axial direction Y1, and "distal" generally refers to the second axial direction Y2.

[0067] In particular, please refer to Figure 1 and Figure 2 , the automatic injection device comprises a housing 10, a syringe 20, a first elastic member 30, a first switch member 40 and an injection button 50.

[0068] As shown in Figure 2 and Figure 3 , the syringe 20 comprises a cartridge 21, a needle 22 and a plunger rod 23. The cartridge 21 is used to store the medicine, and the needle 22 is arranged at the distal end of the cartridge 21 and communicates with the cartridge 21. Part of the plunger rod 23 penetrates into the cartridge 21 from the proximal end of the cartridge 21 and is used to move distally in the cartridge 21 to drive the medicine in the cartridge 21, so as to press the medicine in the cartridge 21 out of the needle 22. Wherein, the needle 22 vertically penetrates into the injection site during the injection process, and the injection site can be the arm, hip, waist or other parts of the human or animal body.

[0069] As shown in Figure 3 and Figure 4 , the plunger rod 23 comprises a rod body 231 and a limiting member 232, and the limiting member 232 is elastically movably arranged on the rod body 231. It can be understood that the limiting member 232 is connected to the rod body 231 and can elastically move relative to the rod body 231. At least part of the rod body 231 penetrates into the cartridge 21 from the proximal end of the cartridge 21 and is used to move distally in the cartridge 21 to drive the medicine in the cartridge 21. The housing 10 is sleeved on the rod body 231, and the limiting member 232 is configured to abut against the housing 10 distally. It can be understood that the limiting member 232 abuts against the housing 10 distally, which realizes the limiting of the plunger rod 23 distally.

[0070] Please continue to refer to Figure 3 and Figure 4 , the first elastic member 30 is used to apply an elastic force to the rod body 231 towards the distal end, so as to drive the rod body 231 to move distally to perform injection work. Wherein, the first elastic member 30 can be a spring, a tension spring, a spring sheet or other elastic structure.

[0071] Please refer to Figures 1 to 4 , the first switch member 40 is movably arranged on the housing 10 to switch between an open state and a closed state. It can be understood that when the first switch member 40 moves relative to the housing 10, it can be moved to the open state or the closed state.

[0072] Please continue to refer toFigures 1 to 4 The injection button 50 is arranged on the housing 10 and is axially movable relative to the housing 10. Optionally, the injection button 50 is arranged at the proximal end of the housing 10, which is convenient for a user to operate the injection button 50.

[0073] When the first switch member 40 is in the closed state, as shown in Figure 3 and Figure 4 , the injection button 50 abuts against the first switch member 40 in the distal direction, and is spaced apart from the limiting member 232. At this time, the injection button 50 cannot move in the distal direction under the limitation of the first switch member 40, and thus cannot drive the limiting member 232, so that the limiting relationship between the limiting member 232 and the housing 10 can be maintained at this time. In other words, the injection button 50 cannot drive the plunger rod 23 at this time, so that the plunger rod 23 cannot drive the medicine in the medicine cartridge 21 in the distal direction, i.e., the injection work of the medicine cannot be performed.

[0074] When the first switch member 40 is in the open state, as shown in Figure 5 to 9 , the injection button 50 is spaced apart from the first switch member 40. In this way, the injection button 50 can move in the distal direction under an external force to drive the limiting member 232, so that the limiting member 232 is separated from the housing 10. That is, the injection button 50 removes the limiting relationship between the limiting member 232 and the housing 10 under the external force. At this time, since the first elastic member 30 applies an elastic force in the distal direction to the rod body 231, the rod body 231 can move in the distal direction under the elastic force of the first elastic member 30 and drive the medicine in the medicine cartridge 21, i.e., the injection work of the medicine can be performed.

[0075] It should be noted that when the limiting member 232 abuts against the housing 10 in the distal direction, the first elastic member 30 is in a force storage state, and when the first elastic member 30 is a spring or a spring sheet, the first elastic member 30 is in a compressed state at this time. When the injection button 50 removes the limiting relationship between the limiting member 232 and the housing 10 under the external force, the first elastic member 30 resets to make the rod body 231 and the limiting member 232 move in the distal direction together and be separated from the injection button 50, and thus the rod body 231 drives the medicine in the medicine cartridge 21 in the distal direction, i.e., the injection work of the medicine is performed, as shown in Figure 8 and Figure 9 . At this time, the first elastic member 30 has recovered from the force storage state to a natural state, the limiting member 232, the rod body 231 and the first elastic member 30 are all located in the housing 10, so that the first elastic member 30 is difficult to recover to the force storage state again, and the limiting member 232 and the rod body 231 are also difficult to move in the proximal direction to the initial state again, so that the plunger rod 23 cannot be used again. That is, the automatic injection device cannot be used again, so that the performance of one-time use of the automatic injection device is achieved. Furthermore, as shown in Figures 6 to 9As shown, the shell 10 is sleeved on the rod body 231, and the injection button 50 is arranged at the proximal end of the shell 10, so that the plunger rod 23 and the first elastic member 30 are located in the space enclosed by the shell 10 and the injection button 50. In this way, after the plunger rod 23 drives the medicine in the medicine cartridge 21, that is, after the injection of the medicine is completed, it is difficult for the user to restore the plunger rod 23 and the first elastic member 30 to the initial state, thereby further improving the effect of the one-time use performance of the automatic injection device.

[0076] Based on this, the automatic injection device provided by the embodiment of the present application can first vertically pierce the needle 22 into the injection site when in use. After the needle 22 is vertically pierced into the injection site, the first switch member 40 is driven from the closed state to the open state, as shown. Figures 5 to 7 Then, the injection button 50 is pressed to move the injection button 50 to the distal end, so that the injection button 50 drives the limiting member 232 to move away from the shell 10, and the rod body 231 moves to the distal end under the elastic force of the first elastic member 30 to drive the medicine in the medicine cartridge 21, thereby realizing the injection of the medicine, as shown. Figure 8 Finally, the needle 22 is pulled out of the injection site, as shown. Figure 9

[0077] In the prior art, some disposable automatic injection devices are difficult to completely self-destruct after the injection of the medicine, that is, the automatic injection device can be restored to the initial state by assembly after the injection of the medicine is completed, which leads to the risk that the automatic injection device can be used twice. The automatic injection device provided by the embodiment of the present application drives the limiting member 232 by the injection button 50 under the external force, so that the plunger rod 23 and the first elastic member 30 cannot be restored to the initial state when the plunger rod 23 drives the medicine in the medicine cartridge 21, thereby making the automatic injection device unable to be repeatedly used, that is, the one-time use performance of the automatic injection device is realized.

[0078] ​Therefore, the automatic injection device provided by the embodiment achieves the disposable performance of the automatic injection device through the design of the plunger rod 23, the shell 10 and the first switch piece 40. Specifically, when the first switch piece 40 is in the open state, the injection button 50 can drive the plunger rod 23, so that the plunger rod 23 realizes the one-time injection work, that is, the disposable use effect of the automatic injection device is realized. When the first switch piece 40 is in the closed state, the plunger rod 23 cannot realize the injection work of the medicine. Based on this, during the use process of the automatic injection device, when the needle 22 has not been inserted into the injection site or the needle 22 is inserted into the injection site, the first switch piece 40 can be maintained in the closed state. At this time, the injection button 50 abuts against the first switch piece 40 in the distal direction, so that the injection button 50 cannot move in the distal direction. That is, the injection button 50 cannot drive the limiting piece 232 to move away from the shell 10, and the plunger rod 23 is fixed relative to the shell 10 through the limiting piece 232, so that the rod body 231 of the plunger rod 23 cannot drive the medicine in the medicine cartridge 21, that is, even if the injection button 50 is mistakenly touched, the injection work of the medicine cannot be performed. In this way, the problem that the injection button 50 is mistakenly touched during the process that the needle 22 is inserted into the injection site or the needle 22 is inserted into the injection site, and the medicine is injected in advance can be solved.

[0079] In addition, the automatic injection device provided by the embodiment has a simple structure, is convenient to manufacture, and has low cost.

[0080] When the injection button 50 removes the limiting relationship between the limiting piece 232 and the shell 10 under the external force, and the first elastic piece 30 drives the rod body 231 to drive the medicine in the proximal direction, the rod body 231 can slowly move in the distal direction under the elastic force of the first elastic piece 30, so as to slowly drive the medicine, so that the injection work of the automatic injection device has certain safety performance.

[0081] Optionally, as shown in Figure 3 , Figure 4 , Figure 6 and Figure 7 , one end of the first elastic piece 30 is connected to the rod body 231, and the other end abuts against the injection button 50. When the limiting piece 232 abuts against the shell 10, the first elastic piece 30 is in a force storage state, as shown in Figure 3 and Figure 4 ; when the limiting piece 232 moves away from the shell 10, the first elastic piece 30 resets and drives the rod body 231 and the limiting piece 232 to move in the distal direction away from the injection button 50. Since the first elastic piece 30 is connected to the rod body 231 and abuts against the injection button 50, at this time, the first elastic piece 30 drives the rod body 231 to move in the distal direction away from the injection button 50 under the elastic action of itself, as shown in Figure 8 and Figure 9As shown, in this way, the plunger rod 23 and the first elastic member 30 cannot be reset to the initial state again, thereby helping to improve the one-time use effect of the automatic injection device.

[0082] Optionally, as shown in Figure 3 and Figure 4 , the first elastic member 30 is limited in the rod body 231. Moreover, the rod body 231 has a guide rod 90 extending in the axial direction, the first elastic member 30 is sleeved outside the guide rod 90, and the guide rod 90 is limited in the rod body 231. In this way, the guide effect of the elastic force direction of the first elastic member 30 is achieved, thereby helping the first elastic member 30 to better drive the plunger rod 23 to drive the medicine in the cartridge 21 to the distal end.

[0083] Optionally, the limiting member 232 is provided as at least two, and the at least two limiting members 232 are distributed at intervals on the rod body 231. In the initial state of the automatic injection device, the at least two limiting members 232 abut against the outer shell 10 in the distal direction.

[0084] In some embodiments, the needle 22 and the cartridge 21 are integrally arranged. Moreover, the syringe 20 is a pre-filled syringe, and the medicine in the syringe 20 is pre-filled medicine, that is, the medicine is filled in the cartridge 21 and the needle 22 of the syringe 20.

[0085] Specifically, when the pre-filled medicine is filled, the medicine can be pre-filled in the cartridge 21 and the needle 22, and then the plunger rod 23 is used to block the end of the cartridge 21 away from the needle 22, so that the medicine is filled in the cartridge 21 and the needle 22. The medicine has a certain pressure, and when the plunger rod 23 moves in the distal direction, the medicine will be pushed by the plunger rod 23 and injected from the needle 22.

[0086] In one embodiment, please refer to Figure 2 , the automatic injection device further comprises a pen cap 100, which is used to detachably cover the needle 22 and is also used to disinfect the needle 22.

[0087] The pen cap 100 refers to a structure for covering the needle 22. Specifically, in the case where the needle 22 does not need to be used, covering the needle 22 by the pen cap 100 can achieve the protection effect of the needle 22, and can also solve the problem of accidental injury of the user by the needle 22.

[0088] The pen cap 100 also has a disinfection function. Specifically, in the case where the pen cap 100 covers the needle 22, the needle 22 can be disinfected by the pen cap 100, thereby achieving the sterile use effect of the needle 22.

[0089] By adopting the above technical solution, the needle cap 100 can cover the needle 22, and the needle cap 100 can disinfect the needle 22 based on the protection effect of the needle cap 100 on the needle 22.

[0090] In one embodiment, referring to Figure 2 、 Figures 23 to 25 The needle cap 100 includes a cap body 110, a disinfection device 120, and a second switch 130. At least part of the cap body 110 is used to detachably cover the needle 22. The disinfection device 120 is arranged on the cap body 110 and is used to disinfect the needle 22 when the cap body 110 covers the needle 22. The second switch 130 is arranged on the cap body 110 and is electrically connected to the disinfection device 120 and is used to at least turn on the disinfection device 120.

[0091] The cap body 110 refers to a structure for covering the needle 22.

[0092] The disinfection device 120 refers to a device for disinfection. As an example, the disinfection device 120 is an ultraviolet lamp. When the cap body 110 covers the needle 22, the disinfection device 120 can emit ultraviolet light to the needle to disinfect the needle 22.

[0093] The second switch 130 refers to a switch structure for turning on the disinfection device 120. The second switch 130 can be a touch switch or a press button. Taking the second switch 130 as a press button as an example, when the cap body 110 covers the needle 22, the user can press the second switch 130 to turn on the disinfection device 120 and disinfect the needle 22. As an example, the second switch 130 can be in the form of a soft rubber sheet, which is convenient for the second switch 130 to be operated.

[0094] By adopting the above technical solution, the disinfection device 120 can be turned on by the second switch 130 to disinfect the needle 22.

[0095] In some embodiments, referring to Figures 23 to 25 The disinfection device 120 is arranged in the cap body 110. When the cap body 110 covers the needle 22, the disinfection device 120 is located at the distal end of the needle 22, so that the disinfection device 120 can disinfect the needle 22.

[0096] In some embodiments, referring to Figures 23 to 25 The second switch 130 is arranged on the cap body 110 and is exposed outside the cap body 110, which is convenient for the user to operate the second switch 130. As an example, as shown in Figures 23 to 25As shown, the second switch member 130 is located at the distal end of the sterilization member 120 and exposed outside the distal end of the cap 110, so as to facilitate the user to operate the second switch member 130.

[0097] In some embodiments, as shown in Figures 23 to 25 As shown, the second switch member 130 is located at the distal end of the sterilization member 120 and exposed outside the distal end of the cap 110, so as to facilitate the user to operate the second switch member 130.

[0098] In some embodiments, the cap 100 further comprises a battery, which is electrically connected to the sterilization member 120 and used to supply power to the sterilization member 120, so that the sterilization member 120 can sterilize the needle 22.

[0099] In some embodiments, the sterilization member 120 is configured to be turned off after a predetermined sterilization time. Specifically, when the cap 100 is in operation, the cap 110 can be first covered on the needle 22, and then the second switch member 130 is operated to turn on the sterilization member 120 and sterilize the needle 22. The sterilization member 120 is automatically turned off after a predetermined sterilization time, so as to stop sterilizing the needle 22. In this way, on the one hand, the waste of the sterilization member 120 can be reduced, and on the other hand, the control work of the sterilization member 120 can be reduced.

[0100] It can be understood that the battery, the sterilization member 120, the second switch member 130 and the like form an electric circuit, which is provided with a delay circuit. Through the setting of the delay circuit, the sterilization member 120 is turned off after a predetermined sterilization time. The predetermined time can be set according to actual needs.

[0101] In some embodiments, as shown in Figures 23 to 25 The cap 110 can comprise a base 1110 and a first cap 1120 arranged on the base 1110. The first cap 1120 is in the form of a sleeve and is used to cover the needle 22. The sterilization member 120 and the second switch member 130 are arranged on the base 1110, and at least part of the sterilization member 120 is exposed to the first cap 1120, so that the ultraviolet light emitted by the sterilization member 120 can sterilize the needle 22 through the first cap 1120.

[0102] In some embodiments, as shown in Figures 23 to 26 The cap 110 can further comprise a second cap 1130, which is sleeved outside the first cap 1120. The second cap 1130 is used to be sleeved outside the shell 10 to form a detachable connection with the shell 10.

[0103] As an example, as shown in Figure 26As shown, the inner circumferential wall of the second cap 1130 is provided with a groove 1131, and the outer circumferential wall of the shell 10 is provided with a protrusion 1121. When the second cap 1130 is sleeved on the shell 10, the protrusion 1121 is clamped in the groove 1131, so as to realize the detachable connection between the second cap 1130 and the shell 10.

[0104] In some embodiments, the syringe 20 can further comprise a needle cap 24, which is used to detachably plug the needle 22 to seal and protect the needle 22.

[0105] Based on this, when the cap body 110 covers the needle 22, the cap body 110 can cover the needle cap 24 and the needle 22 at the same time.

[0106] Among them, the needle cap 24 is transparent, so that the ultraviolet light emitted by the sterilization device 120 can pass through the needle cap 24, thereby realizing the sterilization work of the needle 22.

[0107] When the syringe 20 is a pre-filled syringe, after the medicine is pre-filled in the barrel 21 and the needle 22, the plunger rod 23 can then plug the end of the barrel 21 away from the needle 22, so that the medicine is filled in the barrel 21 and the needle 22, and the needle 22 is sealed and protected by the needle cap 24.

[0108] In some embodiments, the first cap 1120 can be provided with a buckle 11210. When the first cap 1120 is removed from the needle 22, the buckle 11210 of the first cap 1120 can drive the needle cap 24 to move, so that the needle cap 24 and the cap 100 are removed from the needle 22 at the same time, thereby reducing the use steps of the automatic injection device.

[0109] In some embodiments, the cap body 110 is transparent, so as to facilitate the observation of the working condition of the sterilization device 120 in the cap body 110.

[0110] In one embodiment, please refer to Figure 3 、 Figure 4 、 Figure 8 、 Figures 10 to 12 The limiting member 232 comprises a first elastic arm 2321 and a barb 2322, the barb 2322 is arranged on the first elastic arm 2321, and the opening formed by the barb 2322 and the first elastic arm 2321 faces the distal end, and the first elastic arm 2321 is arranged on the rod body 231. In the initial state, as shown in Figure 3 and Figure 4As shown, the barb 2322 hooks the outer shell 10 distally, and the abutting relationship between the limiting member 232 and the outer shell 10 is achieved. When the first switch member 40 is in the open state, and the injection button 50 moves distally under external force, the injection button 50 extrudes the barb 2322 distally, so that the barb 2322 elastically moves relative to the rod body 231 under the joint action of the first elastic arm 2321 and the injection button 50, and is separated from the outer shell 10, thereby achieving the effect that the limiting relationship between the limiting member 232 and the outer shell 10 is removed. Figure 8 As shown.

[0111] In another embodiment, the limiting member 232 does not include the first elastic arm 2321 and the barb 2322 described above, but includes a spring sheet (not shown in the figure). The spring sheet is arranged on the rod body 231, and the opening formed by the spring sheet and the rod body 231 faces distally. In the initial state, the spring sheet hooks the outer shell 10 distally. When the first switch member 40 is in the open state, and the injection button 50 moves distally under external force, the injection button 50 extrudes the spring sheet distally, so that the spring sheet is separated from the outer shell 10, thereby achieving the effect that the limiting relationship between the limiting member 232 and the outer shell 10 is removed.

[0112] In another embodiment, the limiting member 232 is provided as at least two, at least one of which includes the first elastic arm 2321 and the barb 2322 described above, and at least one of which includes the spring sheet described above.

[0113] In one embodiment, please refer to Figure 10 and Figure 11 , the outer shell 10 is provided with a limiting groove 101, and the limiting member 232 is arranged to be circumferentially limited in the limiting groove 101. In this way, when the automatic injection device is in the initial state, the limiting member 232 abuts against the groove wall of the limiting groove 101 distally, and is circumferentially limited in the limiting groove 101, thereby achieving the positioning of the limiting member 232 in the circumferential direction, which can avoid the rotation of the limiting member 232 relative to the outer shell 10. In this way, when the injection button 50 moves distally, the injection button 50 can accurately contact and extrude the limiting member 232, thereby accurately achieving the contact of the limiting relationship between the limiting member 232 and the outer shell 10, which is beneficial to the distal driving of the plunger rod 23 to the medicine in the cartridge 21.

[0114] In one embodiment, please refer to Figures 3 to 9 , Figure 13 and Figure 14 , the injection button 50 and the outer shell 10 are mutually sleeved; and the injection button 50 has a first extrusion part 55, the first extrusion part 55 and the limiting member 232 are arranged to face each other in the axial direction, and the first extrusion part 55 is used to extrude the limiting member 232 distally to remove the limiting relationship between the limiting member 232 and the outer shell 10. Please continue to refer to Figure 13 andFigure 14 The injection button 50 is provided with a first guide rail 51 extending in the axial direction, and the shell 10 is provided with a sliding groove 102 extending in the axial direction, and the first guide rail 51 is slidably arranged in the sliding groove 102.

[0115] In this way, when the first switch member 40 is switched to the open state and the injection button 50 moves distally under the external force, the first guide rail 51 moves distally in the sliding groove 102, at this time, the injection button 50 and the shell 10 are sleeved with each other, realizing the radial limiting between the injection button 50 and the shell 10, the first guide rail 51 is slidably arranged in the sliding groove 102, realizing the circumferential limiting between the injection button 50 and the shell 10, and further limiting the relative rotation between the injection button 50 and the shell 10, so that the injection button 50 can only move relative to the shell 10 in the axial direction, realizing the guiding effect of the movement of the injection button 50, so that after the injection button 50 moves distally, the first extrusion part 55 can accurately contact and extrude the limiting member 232, and further accurately and effectively release the limiting relationship between the limiting member 232 and the shell 10, facilitating the driving work of the plunger rod 23 on the medicine.

[0116] Specifically, as shown in Figure 13 , the first guide rail 51 and the first extrusion part 55 are spaced apart.

[0117] In other embodiments, the sliding groove 102 can also be provided on the injection button 50, and correspondingly, the first guide rail 51 is provided on the shell 10; or the injection button 50 is provided with the sliding groove 102 and the first guide rail 51 at the same time, and the shell 10 is also provided with the first guide rail 51 and the sliding groove 102 at the same time.

[0118] Optionally, as shown in Figure 4 , Figure 10 , Figure 12 and Figure 13 , the proximal end side of the barb 2322 or the spring of the limiting member 232 has a first extrusion surface 2301 for extrusion by the first extrusion part 55, and the first extrusion surface 2301 is an inclined surface, a circular arc surface or a free curved surface; the distal end side of the first extrusion part 55 has a second extrusion surface 5501, and the second extrusion surface 5501 is an inclined surface, a circular arc surface or a free curved surface. In this way, the first extrusion part 55 can extrude the first extrusion surface 2301 of the limiting member 232 through the second extrusion surface 5501 thereon, thereby helping the first extrusion part 55 to extrude the limiting member 232 to be separated from the shell 10, thereby releasing the limiting relationship between the limiting member 232 and the shell 10.

[0119] Optionally, as shown in Figure 4 , Figure 10 , Figure 11 and Figure 13As shown, the first extruding part 55 is axially opposite to the limiting groove 101 of the shell 10. When the first switch part 40 is switched to the open state and the injection button 50 is moved distally under the external force, the first extruding part 55 is inserted into the limiting groove 101 distally, thereby extruding the limiting part 232 in the limiting groove 101 out of the limiting groove 101, and the limiting relationship between the limiting part 232 and the shell 10 is released.

[0120] In one embodiment, referring to Figure 2 , Figure 4 , Figure 7 , Figure 11 and Figure 13 , the second elastic part 60 is arranged between the shell 10 and the injection button 50, and is used to apply an elastic force to the injection button 50 towards the proximal end, so that the injection button 50 is separated from the limiting part 232. It can be understood that the second elastic part 60 abuts between the shell 10 and the injection button 50. The shell 10 is provided with a first limiting part 121, and the injection button 50 is provided with a second limiting part 52, which is used to abut the first limiting part 121 towards the proximal end, and the first limiting part 121 abuts the second limiting part 52 towards the distal end.

[0121] In this way, on the one hand, the injection button 50 has a tendency to move distally under the action of the second elastic part 60, so that when the injection button 50 is not moved distally under the external force, the spacing distribution effect between the injection button 50 and the limiting part 232 can be maintained, and the problem that the limiting relationship between the limiting part 232 and the shell 10 is released by the injection button 50 when the injection button 50 is not triggered by the external force can be avoided. On the other hand, when the injection button 50 is moved proximally under the elastic force of the second elastic part 60, the second limiting part 52 of the injection button 50 abuts the first limiting part 121 towards the proximal end, thereby achieving the limiting of the injection button 50 towards the proximal end, so that the injection button 50 can be prevented from separating from the shell 10 towards the proximal end. In this way, when it is necessary to release the limiting relationship between the limiting part 232 and the shell 10 by the injection button 50 to achieve the injection of the medicine, it is not necessary to additionally install the injection button 50, so that the axial alignment effect between the injection button 50 and the limiting part 232 can be maintained, which is beneficial to the subsequent accurate extrusion of the limiting part 232 by the injection button 50, thereby improving the accuracy and efficiency of the injection work of the automatic injection device. In addition, the abutting relationship between the second limiting part 52 and the first limiting part 121 can prevent the injection button 50 from separating from the shell 10 towards the proximal end, so that after the plunger rod 23 drives the medicine in the cartridge 21 distally, the problem that the user removes the injection button 50 from the shell 10 and restores the plunger rod 23 and the first elastic part 30 to the initial state can be solved, so that the one-time use effect of the automatic injection device can be further maintained, thereby avoiding the problem of cross infection caused by repeated use of the automatic injection device.

[0122] The second elastic member 60 can be a spring, a tension spring, a spring sheet, or the like.

[0123] In one embodiment, referring to Figure 2 , Figure 4 , Figure 10 and Figure 11 , the shell 10 includes a housing 11 and a fixing member 12, the fixing member 12 is assembled in the housing 11; the cartridge 21 is fixed in the housing 11, the fixing member 12 is sleeved on the rod body 231, and the limiting member 232 can abut against the fixing member 12 in the distal direction. The first switch member 40 is arranged on the housing 11 and / or the fixing member 12, and can rotate relative to the housing 11 and the fixing member 12 in the axial direction, so as to be alternately rotated to the open state and the closed state. In this way, the first switch member 40 can be alternately switched to the open state or the closed state by rotating between the housing 11 and the fixing member 12, so as to improve the switching stability of the first switch member 40.

[0124] The first switch member 40 is axially limited in the housing 11, or the first switch member 40 is axially limited in the fixing member 12, or the first switch member 40 is axially limited in the housing 11 and the fixing member 12. In this way, when the first switch member 40 is rotated to the closed state, the injection button 50 abuts against the first switch member 40 in the distal direction, so as to indirectly achieve the effect of limiting the injection button 50 in the distal direction relative to the shell 10.

[0125] Specifically, as shown in Figure 11 , the limiting groove 101 is arranged on the fixing member 12.

[0126] Specifically, as shown in Figure 4 , the second elastic member 60 abuts between the fixing member 12 and the injection button 50.

[0127] Referring to Figure 13 , the injection button 50 further includes a button body 53.

[0128] Specifically, as shown in Figure 4 and Figure 13 , the first guide rail 51 and the first extrusion part 55 are arranged on the button body 53. The one end of the second elastic member 60 away from the shell 10 in the axial direction abuts on the button body 53. And the one end of the first elastic member 30 away from the rod body 231 in the axial direction also abuts on the button body 53.

[0129] Referring to Figure 4 and Figure 13, the injection button 50 further comprises a first annular portion 54 and the first extrusion portion 55 described above, the first annular portion 54 is arranged on the button body 53, and the first extrusion portion 55 is arranged in the first annular portion 54; the first extrusion portion 55 is used for extruding the limiting piece 232 to the distal end, so as to drive the limiting piece 232 to disengage from the fixing piece 12, thereby releasing the limiting relationship between the limiting piece 232 and the fixing piece 12. As shown in Figure 4 and Figure 10 , the annular groove 104 is arranged between the shell 11 and the fixing piece 12, the first annular portion 54 is arranged in the annular groove 104, and the first annular portion 54 can move axially relative to the fixing piece 12. At least part of the first switch piece 40 is arranged in the annular groove 104 and is arranged in axial opposite to the first annular portion 54. When the first switch piece 40 is in the closed state, as shown in Figure 4 , the first annular portion 54 abuts against the first switch piece 40 to the distal end, so as to indirectly realize the limiting of the first extrusion portion 55 to the distal end, so that the first extrusion portion 55 cannot drive the limiting piece 232 to the distal end under external force. When the first switch piece 40 is in the open state, as shown in Figure 7 , the first annular portion 54 is spaced from the first switch piece 40 and can move to the distal end, so as to facilitate the first extrusion portion 55 to extrude the limiting piece 232 to the distal end, thereby releasing the limiting relationship between the limiting piece 232 and the fixing piece 12.

[0130] Among them, the first annular portion 54 is arranged in the annular groove 104, so that the first annular portion 54 is limited between the inner circumferential side of the shell 11 and the outer circumferential side of the fixing piece 12 in the radial direction, which is helpful to realize the movement of the first annular portion 54 in the axial direction.

[0131] Specifically, as shown in Figure 4 , Figure 7 , Figure 11 and Figure 13 , the first limiting portion 121 is arranged on the outer circumferential side of the fixing piece 12, and the second limiting portion 52 is arranged on the inner circumferential side of the first annular portion 54. Of course, in other embodiments, the first limiting portion 121 can also be arranged on the inner circumferential side of the shell 11, and correspondingly, the second limiting portion 52 is arranged on the outer circumferential side of the first annular portion 54.

[0132] Specifically, as shown in Figure 13 and Figure 14 , the first guide rail 51 is arranged on the outer circumferential side of the first annular portion 54, and the sliding groove 102 is arranged on the inner circumferential side of the shell 11. In other embodiments, when the injection button 50 is provided with the sliding groove 102, the sliding groove 102 is arranged on the outer circumferential side of the first annular portion 54; when the shell 10 is provided with the first guide rail 51, the first guide rail 51 is arranged on the inner circumferential side of the shell 11.

[0133] Specifically, as shown in Figure 4As shown, the one end of the first elastic member 30 away from the rod body 231 and the one end of the second elastic member 60 away from the fixing member 12 are both abutted against the button body 53 and located in the first annular portion 54.

[0134] Specifically, as shown in Figure 13 , the injection button 50 further comprises a second annular portion 56, the second annular portion 56 is arranged on the button body 53, the first annular portion 54 is arranged on the outer periphery of the second annular portion 56 in a spaced ring manner, and the first extrusion portion 55 is arranged on the second annular portion 56. As shown in Figure 11 , the fixing member 12 further comprises a sleeve 122 and a third annular portion 123 arranged in the sleeve 122, the first limiting portion 121 is arranged on the outer periphery side of the sleeve 122, and the limiting groove 101 is arranged on the third annular portion 123. As shown in Figure 4 , one end of the second elastic member 60 abutting the fixing member 12 is sleeved between the sleeve 122 and the third annular portion 123, and the other end of the second elastic member 60 abutting the injection button 50 is sleeved between the first annular portion 54 and the second annular portion 56. It should be noted that when the injection button 50 moves distally under external force, the second annular portion 56 is inserted between the sleeve 122 and the third annular portion 123, and the first extrusion portion 55 can be directly inserted into the limiting groove 101, which further improves the guiding effect of the first extrusion portion 55 extruding the limiting member 232, thereby facilitating the effect of the plunger rod 23 driving the medicine in the medicine cartridge 21. And as shown in Figure 4 , the outer periphery side of the sleeve 122 and the inner periphery side of the shell 11 define the annular groove 104.

[0135] In one embodiment, referring to Figure 1 , Figure 10 and Figure 15 , the first switch member 40 comprises a limiting ring 41, the limiting ring 41 is rotatably arranged in the annular groove 104 and axially opposite to the first annular portion 54; wherein the limiting ring 41 is radially limited to the inner periphery side of the shell 11 and the outer periphery side of the fixing member 12. The limiting ring 41 is provided with a protrusion 42, and the first annular portion 54 is provided with an avoiding groove 501. When the first switch member 40 is in the closed state, the protrusion 42 is configured to limit the first annular portion 54 to move distally, specifically, as shown in Figure 4As shown, the convex portion 42 and the avoiding groove 501 are circumferentially staggered, and the convex portion 42 abuts against the first annular portion 54, so that the injection button 50 is limited to move distally relative to the shell 10, and the injection button 50 cannot be pressed distally by the first pressing portion 55 to press the limiting piece 232 under external force. When the first switch piece 40 is in the open state, the convex portion 42 and the avoiding groove 501 are axially opposite, so that the injection button 50 can move distally under external force, so that the first pressing portion 55 presses the limiting piece 232 distally to release the limiting relationship between the limiting piece 232 and the fixed piece 12, and at this time, the convex portion 42 is inserted into the avoiding groove 501, so that the first pressing portion 55 can press the limiting piece 232.

[0136] The limiting ring 41 is axially limited in the shell 11, or the limiting ring 41 is axially limited in the fixed piece 12, or the limiting ring 41 is axially limited in the shell 11 and the fixed piece 12.

[0137] In another embodiment, the convex portion 42 is arranged on the first annular portion 54, and the avoiding groove 501 is arranged on the limiting ring 41. Alternatively, in other embodiments, the limiting ring 41 is provided with the convex portion 42 and the avoiding groove 501, and the first annular portion 54 is also provided with the avoiding groove 501 and the convex portion 42.

[0138] Specifically, as shown in Figure 10 , Figure 14 and Figures 15 to 17 , the shell 11 is provided with a sliding groove 103, and the sliding groove 103 and the sliding groove 102 are spaced apart. The first switch piece 40 further comprises a trigger portion 45 and a connecting portion 46, and the connecting portion 46 is connected between the trigger portion 45 and the limiting ring 41. The trigger portion 45 is located outside the shell 11, so as to be triggered by the user to rotate the limiting ring 41 to the open state or the closed state. The connecting portion 46 is axially limited in the sliding groove 103 to indirectly limit the limiting ring 41 in the axial direction relative to the shell 11 and the fixed piece 12, and the connecting portion 46 can also slide along the sliding groove 103; specifically, the trigger portion 45 can slide under external force, so that the connecting portion 46 slides along the sliding groove 103, thereby realizing the rotating effect of the limiting ring 41 relative to the shell 11 and the fixed piece 12.

[0139] In one embodiment, referring to Figures 15 to 17 , the first switch piece 40 is configured to be locked relative to the injection button 50 and the shell 10 in the open state, so that the first switch piece 40 cannot be moved again relative to the injection button 50 and the shell 10, that is, the first switch piece 40 cannot be switched to the closed state again, when the injection button 50 removes the abutting relationship between the limiting piece 232 and the shell 10 under external force.

[0140] Specifically, as shown in Figure 17The convex portion 42 has an elastic hook 421 configured to be clamped in the avoiding groove 501 after the first extruding portion 55 extrudes the limiting member 232.

[0141] It can be understood that when the first switch member 40 is switched from the closed state to the open state, the elastic hook 421 is axially opposite to the avoiding groove 501. At this time, when the injection button 50 moves distally under the external force, the first extruding portion 55 extrudes the limiting member 232 distally to make the limiting member 232 disengage from the shell 11, and the plunger rod 23 drives the medicine in the medicine cartridge 21 distally under the elastic force of the first elastic member 30. At the same time, the avoiding groove 501 moves axially opposite to the elastic hook 421 under the driving of the injection button 50 to make the elastic hook 421 axially penetrate into the avoiding groove 501 and be clamped in the avoiding groove 501. Thus, the relative locking between the first switch member 40 and the injection button 50 is achieved, which can prevent the first switch member 40 from rotating again, that is, prevent the first switch member 40 from being switched from the open state to the closed state. In this way, after the automatic injection device completes the injection of the medicine, the first elastic member 30 and the plunger rod 23 cannot be restored to the initial state, and the first switch member 40 cannot be switched from the open state to the closed state, that is, cannot be restored to the initial state, further achieving the one-time use performance of the automatic injection device. Moreover, the first switch member 40 cannot rotate again, which is also helpful to achieve the limiting effect of the protective sleeve 70 described below. How to achieve the limiting effect can be referred to the description below.

[0142] Specifically, as shown in Figure 16 , when the elastic hook 421 is clamped in the avoiding groove 501, the elastic hook 421 hooks the bottom wall of the avoiding groove 501 distally, which can prevent the elastic hook 421 from disengaging from the avoiding groove 501, and the elastic hook 421 is also circumferentially limited in the avoiding groove 501, which can prevent the first switch member 40 from rotating again, thereby preventing the first switch member 40 from being switched from the open state to the closed state.

[0143] As shown in Figure 17 and Figure 2 , each convex portion 42 includes at least two elastic hooks 421, which is helpful to improve the firmness of the relative locking between the first switch member 40 and the injection button 50. The elastic hooks 421 are arranged on the limiting ring 41.

[0144] In one embodiment, referring to Figure 3 and Figure 1 , the automatic injection device further includes a protective sleeve 70. The shell 10 is sleeved on the medicine cartridge 21, and the protective sleeve 70 is arranged between the medicine cartridge 21 and the shell 10 and can axially move relative to the medicine cartridge 21 and the shell 10 to retract into the shell 10 or extend outward from the distal end of the shell 10.

[0145] Understandably, when the automatic injection device is in its initial state, such as... Figure 3 and Figure 6 As shown, the protective sleeve 70 extends beyond the distal end of the outer casing 10 and covers the needle 22, thereby concealing the needle 22 and minimizing the risk of the needle 22 pricking the user. When the automatic injection device is in use, the needle 22 is first inserted vertically into the injection site. The protective sleeve 70 moves proximally under the reaction force of the injection site to retract into the outer casing 10. At this time, the first switch 40 can be switched to the open state, specifically as follows... Figure 7 and Figure 8 As shown; then, the injection button 50 is activated, causing the injection button 50 to release the limiting relationship between the limiting member 232 and the outer shell 10. Under the elastic force of the first elastic member 30, the rod 231 drives the medicine in the cartridge 21 to the distal end to realize the injection of the medicine, specifically as follows. Figures 1 to 3 As shown; finally, the needle 22 is pulled out from the injection site, and the reaction force of the injection site on the protective sleeve 70 is removed. At this time, the protective sleeve 70 can be extended out of the far end of the outer shell 10 again and cover the needle 22 again to achieve the concealment of the needle 22.

[0146] Specifically, such as Figure 15 As shown, the outer casing 10 includes the aforementioned housing 11 and fixing member 12. The housing 11 includes a first housing 111 and a second housing 112. The first housing 111 is located at the distal end of the second housing 112 and is connected to the second housing 112. The fixing member 12 is located inside the first housing 111, and both the sliding groove 102 and the sliding groove 103 are formed in the first housing 111. The first switching member 40 is annularly arranged between the fixing member 12 and the first housing 111. The second housing 112 is sleeved on and connected to the cartridge 21, and a protective sleeve 70 is sleeved between the second housing 112 and the cartridge 21. More specifically, the housing 11 also includes a fixing housing 113, which is assembled inside the second housing 112. The cartridge 21 passes through the fixing housing 113 and is assembled to the fixing housing 113, thereby indirectly realizing the connection between the cartridge 21 and the second housing 112.

[0147] In one embodiment, please refer to [the relevant documentation / reference]. Figures 18 to 20 , Figure 3 The protective sleeve 70 has a second elastic arm 71 at its proximal end, and the first switch member 40 has a third elastic arm 43 at its distal end. When the protective sleeve 70 is retracted into the outer shell 10, the third elastic arm 43 is configured to compress the second elastic arm 71 during the switching process of the first switch member 40 from the closed state to the open state, so that the third elastic arm 43 and the second elastic arm 71 are offset from each other; when the injection is completed, when the protective sleeve 70 extends beyond the distal end of the outer shell 10, the second elastic arm 71 simultaneously pops out distally, and after popping out, the distal end of the third elastic arm 43 abuts against the proximal end of the second elastic arm 71.

[0148] Specifically, please refer to Figure 21 and Figure 3 , the protective sleeve 70 comprises a sleeve 73 and the second elastic arm 71 described above, the second elastic arm 71 is arranged at the proximal end of the sleeve 73, and the sleeve 73 is sleeved between the outer shell 10 and the cartridge 21. Specifically, the cartridge 21 is sleeved between the second shell 112 and the fixed shell 113.

[0149] Understandably, in the initial state, as shown in Figure 18 and Figure 5 , the sleeve 73 protrudes out of the distal end of the outer shell 10, and covers the needle 22 to achieve the hiding of the needle 22; the third elastic arm 43 is located on the proximal side of the second elastic arm 71, and at this time the first switch element 40 is in the closed state, the third elastic arm 43 and the second elastic arm 71 are arranged in the circumferential direction, that is, at this time the second elastic arm 71 and the third elastic arm 43 are not axially opposite.

[0150] When the automatic injection device is in use, the needle 22 is first vertically pierced into the injection site, the sleeve 73 moves towards the proximal end under the reaction of the injection site and is retracted into the outer shell 10, and at the same time the second elastic arm 71 moves towards the proximal end with the sleeve 73 to move to the side of the third elastic arm 43; then, the first switch element 40 is switched to the open state, the third elastic arm 43 presses the second elastic arm 71 and moves relative to the second elastic arm 71, at this time at least part of the second elastic arm 71 and the third elastic arm 43 are deformed, as shown in Figure 6 and Figure 8 , so as to realize the relative displacement of the second elastic arm 71 and the third elastic arm 43, so that the second elastic arm 71 and the third elastic arm 43 can be reset after the sleeve 73 protrudes out of the distal end of the outer shell 10 again, so that the second elastic arm 71 and the third elastic arm 43 are axially opposite and abut.

[0151] Then, the injection button 50 releases the limiting relationship between the limiting part 232 and the outer shell 10 under the external force, so that the rod body 231 drives the medicine in the cartridge 21 under the elastic force of the first elastic part 30 to complete the injection of the medicine, as shown in Figure 19 and Figure 16 ; and at this time the elastic hook 421 of the first switch element 40 is clamped in the displacement slot 501 of the injection button 50, realizing the relative locking between the first switch element 40, the outer shell 10 and the injection button 50, as shown in Figure 17 and Figure 19 .

[0152] Finally, the needle 22 is pulled out from the injection site, the reaction force of the injection site to the sleeve 73 is removed, the sleeve 73 can be extended outside the distal end of the shell 10 again, and the needle 22 is sleeved again to realize the hiding of the needle 22; at the same time, the second elastic arm 71 moves with the sleeve 73 to the distal end side of the third elastic arm 43, at this time, the second elastic arm 71 and the third elastic arm 43 are reset, and the second elastic arm 71 is opposite to and abuts against the third elastic arm 43. In this way, through the mutual abutting action of the second elastic arm 71 and the third elastic arm 43, the limiting of the protective sleeve 70 towards the proximal end is realized, so that the protective sleeve 70 cannot move towards the proximal end again, so that the needle 22 cannot be exposed again, on the one hand, the reuse of the needle 22 is avoided, and the performance of one-time use of the automatic injection device is further realized, on the other hand, after the automatic injection device completes one use, the user can be prevented from being pricked by the needle 22, so that cross infection can be avoided.

[0153] It should be noted that when the injection button 50 releases the limiting relationship between the limiting piece 232 and the shell 10 under the external force, the elastic hook 421 of the first switch piece 40 is clamped in the avoiding groove 501 of the injection button 50, and the relative locking between the first switch piece 40, the shell 10 and the injection button 50 is realized, so that the first switch piece 40 cannot move relative to the shell 10 and the injection button 50 again, so that the abutting state of the third elastic arm 43 of the first switch piece 40 to the second elastic arm 71 can be maintained, so that the protective sleeve 70 cannot be retracted into the shell 10 again, and the needle 22 cannot be exposed to the protective sleeve 70 for use again, so that the performance of one-time use of the automatic injection device is realized. Of course, according to the actual application requirement, a side wall can also be arranged on the second elastic arm 71 or the third elastic arm 43, when the second elastic arm 71 and the third elastic arm 43 abut, the second elastic arm 71 and the third elastic arm 43 can also be limited by the side wall to limit the rotation of the first switch piece 40, and then realize the relative locking between the first switch piece 40, the shell 10 and the injection button 50.

[0154] Wherein, when the protective sleeve 70 is retracted into the shell 10, and the first switch piece 40 is switched to the open state, the third elastic arm 43 moves along the outside of the second elastic arm 71 and presses the second elastic arm 71, so that the second elastic arm 71 is deformed inward along the radial direction, as shown in Figure 21 Of course, according to the actual application requirement, the second elastic arm 71 and the third elastic arm 43 can also be arranged as follows: when the protective sleeve 70 is retracted into the shell 10, and the first switch piece 40 is switched to the open state, the third elastic arm 43 moves along the inside of the second elastic arm 71 and presses the second elastic arm 71, so that the second elastic arm 71 is deformed outward along the radial direction.

[0155] Specifically, asFigure 22 and Figure 3 As shown, the outer periphery of the sleeve 73 is provided with a third limiting part 74, and the inner periphery of the second shell 112 is provided with a fourth limiting part 114. When the first switch 40 is in the open state, the plunger rod 23 completes the injection work, and after the sleeve 73 extends out of the distal end of the shell 10 again, the third limiting part 74 abuts against the fourth limiting part 114 towards the distal end. With this configuration, the second elastic arm 71 abuts against the third elastic arm 43 towards the proximal end, and the third limiting part 74 abuts against the fourth limiting part 114 towards the distal end, realizing the axial movement of the protective sleeve 70. At this time, the protective sleeve 70 cannot move towards the proximal end again, so the needle 22 cannot be exposed again. Furthermore, the protective sleeve 70 cannot be pulled out of the distal end of the shell 10, so the needle 22 cannot be exposed either. This further realizes the disposable performance of the automatic injection device and can prevent the needle 22 from pricking the user and avoid cross-infection.

[0156] Specifically, such as Figure 21 and Figure 15 As shown, the third limiting part 74 has a guide groove 701 that extends axially. Correspondingly, the inner circumferential side of the outer shell 10 has a second guide rail 115 that also extends axially and slides within the guide groove 701. This helps to guide the axial movement of the protective sleeve 70, thereby improving the stability of the automatic injection device. Of course, depending on the actual application requirements, the guide groove 701 can be located on the inner circumferential side of the outer shell 10, and the second guide rail 115 can be located on the outer circumferential side of the sleeve 73.

[0157] In one embodiment, please refer to [the relevant documentation / reference]. Figure 21 and Figure 2 The second elastic arm 71 is provided with a second pressing part 72 on the side facing the third elastic arm 43, and the third elastic arm 43 is provided with a third pressing part 44 on the side facing the second elastic arm 71. The third pressing part 44 is configured to move along the second pressing part 72 to press the second elastic arm 71.

[0158] Specifically, the second pressing part 72 is disposed on the side of the second elastic arm 71 facing the third elastic arm 43 radially, and the third pressing part 44 is disposed on the side of the third elastic arm 43 facing the second elastic arm 71 radially. The opposite sides of the second pressing part 72 and the third pressing part 44 are adapted to each other. In this way, during the process of the first switch 40 switching to the open state, the third elastic arm 43 can press the second pressing part 72 through the third pressing part 44 to achieve the pressing effect on the second elastic arm 71, thereby facilitating the relative deformation and avoidance effect of the second elastic arm 71 and the third elastic arm 43. In this way, when the protective sleeve 70 extends out of the far end of the outer shell 10 again, it is convenient for the second elastic arm 71 to abut against the third elastic arm 43 towards the near end.

[0159] Specifically, the third extrusion part 44 is a protrusion part 42 arranged on one side of the third elastic arm 43, and the second extrusion part 72 is a recessed part arranged on one side of the second elastic arm 71; of course, according to actual application requirements, the second extrusion part 72 can be a protrusion part 42, and correspondingly, the third extrusion part 44 is a recessed part, as long as the relative extrusion of the second elastic arm 71 and the third elastic arm 43 can be realized. The extrusion surface of the second extrusion part 72 is a bevel, an arc surface or a free curved surface, and the extrusion surface of the third extrusion part 44 is a bevel, an arc surface or a free curved surface, which facilitates the relative extrusion of the second elastic arm 71 and the third elastic arm 43, and facilitates the relative sliding of the second elastic arm 71 and the third elastic arm 43 in the process of relative extrusion deformation, so that after the sleeve 73 is extended out of the distal end of the shell 10, the second elastic arm 71 and the third elastic arm 43 can be axially aligned and abutted.

[0160] In one embodiment, referring to Figure 3 and Figure 3 , the automatic injection device further comprises a third elastic member 80 for applying an elastic force to the protective sleeve 70 towards the distal end, so that the protective sleeve 70 is extended out of the distal end of the shell 10 and covers the needle 22.

[0161] Understandably, in the initial state, the protective sleeve 70 is extended out of the distal end of the shell 10 under the elastic action of the third elastic member 80, and is sleeved on the needle 22, so as to realize the hiding of the needle 22, thereby preventing the needle 22 from injuring the user as much as possible. When the automatic injection device completes the injection and the needle 22 is pulled out of the injected part, the reaction force of the injected part on the protective sleeve 70 is gradually removed, and the protective sleeve 70 is gradually extended out of the distal end of the shell 10 under the elastic force of the third elastic member 80, and covers the needle 22 again to realize the hiding of the needle 22.

[0162] The third elastic member 80 can be a spring, a tension spring, a spring sheet or the like structure having elasticity.

[0163] When the needle 22 is vertically inserted into the injected part, the sleeve 73 is retracted into the shell 10 under the reaction force of the injected part, and when the needle 22 is pulled out of the injected part, the reaction force of the injected part on the sleeve 73 is removed, and the sleeve 73 is gradually extended out of the distal end of the shell 10 under the elastic force of the third elastic member 80, that is, the sleeve 73 is extended out of the distal end of the shell 10 by the action of the third elastic member 80, so as to avoid the phenomenon that the protective sleeve 70 is extended out of the distal end of the shell 10 when the needle 22 is not pulled out of the injected part, resulting in the shaking of the needle 22.

[0164] Wherein, the radial direction and the circumferential direction mentioned above are perpendicular to the axial direction, the axial direction can be the axial direction of the plunger rod 23, correspondingly, the radial direction is the radial direction defined by the circle formed on the outer circumferential side of the plunger rod 23, and the circumferential direction is the circumferential direction defined by the circle formed on the outer circumferential side of the plunger rod 23.

[0165] In some embodiments, the automatic injection device comprises a spring connected to the inner circumferential wall of the housing 10, and the outer circumferential wall of the protective sleeve 70 is provided with a clamping groove. After the protective sleeve 70 is retracted into the housing 10 and then extended out of the distal end of the housing 10, the spring is used to reset and be clamped in the clamping groove to at least limit the protective sleeve 70 from being retracted into the housing 10 again.

[0166] It can be understood that in the initial state of the automatic injection device, the spring is elastically deformed and pressed against the outer circumferential wall of the protective sleeve 70, and the end of the spring away from the housing 10 is located at the proximal end of the clamping groove, at this time, the spring is not clamped in the clamping groove. When the protective sleeve 70 is retracted into the housing 10, the clamping groove moves with the protective sleeve 70 to the proximal end of the spring. During the process of the protective sleeve 70 being retracted into the housing 10 and then being extended out of the distal end of the housing 10, when the clamping groove does not move to the distal end of the end of the spring away from the housing 10, but just moves to the end of the spring away from the housing 10, the spring can be clamped in the clamping groove, so that the protective sleeve 70 is difficult to be retracted into the housing 10 again, and the needle 22 is difficult to be used again.

[0167] Specifically, the spring can be connected to the inner circumferential wall of the fixed part 12 of the housing 10.

[0168] Specifically, the clamping groove can be provided on the outer circumferential wall of the sleeve 73 of the protective sleeve 70.

[0169] In other embodiments, the needle 22 vertically penetrates into the injection site, so that after the protective sleeve 70 is retracted into the housing 10, the needle 22 is pulled out of the injection site, and in the case that the protective sleeve 70 is re-extended, the protective sleeve 70 can be limited by other ways with the housing 10, so that the problem that the protective sleeve 70 can be retracted into the housing 10 to expose the needle 22 again can be improved.

[0170] The injection device provided by the embodiments of the present application has the working principle that:

[0171] The automatic injection device is in the initial state, such as Figure 4 、 Figure 18 and Figure 5As shown, the limiting member 232 of the plunger rod 23 abuts against the outer shell 10 at the distal end, specifically, the barb 2322 elastically hooks the outer shell 10 at the distal end. One end of the first elastic member 30 is connected to the rod body 231 of the plunger rod 23, and the other end abuts against the injection button 50. The first elastic member 30 is in a force storage state. The first switch member 40 is in a closed state. The convex portion 42 of the first switch member 40 is not aligned with the avoidance slot 501 of the injection button 50, but is staggered, so that the first annular portion 54 of the injection button 50 abuts against the convex portion 42 at the distal end, thereby unable to move distally. The sleeve 73 of the protective sleeve 70 extends out of the distal end of the outer shell 10 under the elastic action of the third elastic member 80, to cover the needle 22. The third elastic arm 43 of the first switch member 40 is located at the proximal end side of the second elastic arm 71 of the protective sleeve 70. The third elastic arm 43 and the second elastic arm 71 are arranged in a circumferential direction staggered, that is, the second elastic arm 71 and the third elastic arm 43 are not aligned in an axial direction.

[0172] When using the automatic injection device, the needle cap 24 can be first detached from the needle 22, and the needle 22 is vertically inserted into the injection site at the distal end. The sleeve 73 moves proximally under the reaction of the injection site, and is retracted into the outer shell 10, so that the third elastic member 80 is in a force storage state. At the same time, the second elastic arm 71 moves proximally with the sleeve 73, to move to the side of the third elastic arm 43.

[0173] Then, the first switch member 40 is rotated from the closed state to the open state, so that the convex portion 42 of the first switch member 40 is aligned with the avoidance slot 501 of the injection button 50. At this time, the first annular portion 54 of the injection button 50 is not abutted by the convex portion 42, that is, the injection button 50 can move distally. In the process of rotating the first switch member 40 from the closed state to the open state, the third elastic arm 43 rotates relative to the second elastic arm and presses the second elastic arm 71, so that at least part of the second elastic arm 71 and the third elastic arm 43 are relatively deformed, as shown in Figure 6 and Figure 8 Thus, the relative avoidance of the second elastic arm 71 and the third elastic arm 43 is realized, so that after the sleeve 73 is again extended out of the distal end of the outer shell 10, the second elastic arm 71 and the third elastic arm 43 can be reset, so that the second elastic arm 71 and the third elastic arm 43 are aligned and abutted in the axial direction.

[0174] Then, the injection button 50 is pressed to move distally, and the first pressing portion 55 of the injection button 50 presses the limiting member 232 distally, so that the limiting member 232 is separated from the outer shell 10. The first elastic member 30 is reset and drives the plunger rod 23 to move distally, so that the plunger rod 23 pushes the medicine out distally, to realize injection of the medicine, as shown in Figure 19 and Figure 16The elastic hook 421 of the first switch member 40 is clamped in the avoiding slot 501 of the injection button 50, and the relative locking between the first switch member 40, the shell 10 and the injection button 50 is achieved, as shown in Figure 17 and ​ as shown.

[0175] Finally, the needle 22 is pulled out from the injection site, and the reaction force of the injection site to the sleeve 73 is removed, so that the sleeve 73 can be extended from the distal end of the shell 10 under the action of the third elastic member 80 and again cover the needle 22 to achieve the hiding of the needle 22. At the same time, the second elastic arm 71 moves with the sleeve 73 to the distal end and moves to the distal end of the third elastic arm 43. At this time, the second elastic arm 71 and the third elastic arm 43 are reset, and the second elastic arm 71 is opposite and abuts against the third elastic arm 43. In this way, through the mutual abutting action of the second elastic arm 71 and the third elastic arm 43, the limiting of the protective sleeve 70 towards the proximal end is achieved, so that the protective sleeve 70 cannot move towards the proximal end again, so that the needle 22 cannot be exposed again. Thus, the locking and self-destruction effect of the automatic injection device is achieved.

[0176] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An automatic injection device having an axial direction, opposite axial ends of the automatic injection device being a proximal end and a distal end, respectively; the automatic injection device comprising a cartridge and a needle arranged at the distal end of the cartridge, characterized in that, The automatic injection device further comprises: a housing connected to the cartridge; a plunger rod for driving the liquid medicine in the cartridge to a distal end; the plunger rod comprises a rod body and a limiting member elastically movably arranged on the rod body, the housing is sleeved on the rod body, and the limiting member is configured to abut against the housing to a distal end; a first elastic member for applying an elastic force to the rod body towards the distal end to drive the rod body to inject; a first switch member movably arranged on the housing to switch between an open state and a closed state; an injection button axially movably arranged on the housing; in the closed state of the first switch member, the injection button abuts against the first switch member to a distal end, and is spaced apart from the limiting member; in the open state of the first switch member, the injection button is spaced apart from the first switch member, and can move to a distal end under an external force to drive the limiting member to be separated from the housing.

2. The automatic injection device of claim 1, wherein The automatic injection device further comprises a cap, which is used to detachably cover the needle and disinfect the needle.

3. The automatic injection device of claim 2, wherein the needle cover is biased into the extended position by the spring. The cap comprises: a cap body used to at least partially detachably cover the needle; a disinfecting device arranged on the cap body and used to disinfect the needle when the cap body covers the needle; a second switch member arranged on the cap body and electrically connected to the disinfecting device, and used to at least open the disinfecting device.

4. The automatic injection device of claim 1, wherein the needle cover is configured to be removed from the housing after the needle cover has been moved to the second position. The limiting member comprises a first elastic arm and a barb arranged on the first elastic arm, the first elastic arm is arranged on the rod body, the barb is configured to hook the housing to a distal end, and the injection button can press the barb; and / or, the first elastic member comprises a spring sheet arranged on the rod body, the spring sheet is configured to abut against the housing to a distal end, and the injection button can press the spring sheet.

5. The automatic injection device of claim 1, wherein the needle cover is configured to be removed from the housing after the needle cover has been moved to the second position. The injection button and the housing are sleeved with each other, any one of the injection button and the housing is provided with a sliding groove extending along an axial direction, and the other one is provided with a first guide rail sliding in the sliding groove; the injection button has a first pressing portion, and the first pressing portion and the limiting member are arranged opposite to each other along the axial direction.

6. An auto-injector according to any one of claims 1-5, wherein, The housing comprises a shell and a fixing member assembled in the shell, the cartridge is fixed in the shell, the fixing member is sleeved on the rod body, and the limiting member can abut against the fixing member to a distal end; The injection button comprises a button body, a first annular portion arranged on the button body, and a first pressing portion arranged in the first annular portion; the shell and the fixing member define an annular groove, the first annular portion is axially movably arranged in the annular groove; the first switch member is rotatably arranged on the shell and / or the fixing member, and can be alternately rotated to the open state and the closed state, and at least part of the first switch member is arranged in the annular groove; The first switch piece is in the closed state, and the first annular part abuts against the first switch piece in the distal direction; the first switch piece is in the open state, and the first annular part is spaced apart from the first switch piece and can move in the distal direction; the first extrusion part can extrude the limiting part in the distal direction to make the limiting part disengage from the fixing part.

7. The automatic injection device of claim 6, wherein the needle cover is biased into the extended position by the spring. The first switch piece comprises a limiting ring rotatably arranged in the annular groove and axially opposite to the first annular part; any one of the limiting ring and the first annular part is provided with a convex part, and the other is provided with a spacing groove; in the open state of the first switch piece, the convex part is configured to be axially opposite to the spacing groove to allow the button body to move in the distal direction under an external force; in the closed state of the first switch piece, the convex part is configured to limit the first annular part to move in the distal direction.

8. The automatic injection device of claim 7, wherein the needle cover is biased into the extended position by the spring. The convex part has an elastic hook configured to be clamped in the spacing groove after the first extrusion part extrudes the limiting part.

9. An auto-injector as claimed in any of claims 1 to 5 wherein, The automatic injection device further comprises a protective sleeve, the housing is sleeved on the cartridge, the protective sleeve is sleeved between the cartridge and the housing and can move in the axial direction to retract into the housing or extend out of the distal end of the housing; The proximal end of the protective sleeve has a second elastic arm, and the distal end of the first switch piece has a third elastic arm; When the protective sleeve retracts into the housing, the third elastic arm is configured to extrude the second elastic arm during the switching of the first switch piece to the open state; When the protective sleeve extends out of the distal end of the housing, the third elastic arm is configured to abut against the second elastic arm in the distal direction in the open state.

10. The automatic injection device of claim 9, wherein the needle cover is biased into the extended position by a spring. The automatic injection device further comprises a third elastic member for applying a distally directed elastic force to the protective sleeve to make the protective sleeve extend out of the distal end of the housing and cover the needle.

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