Automatic injection device

Abstract

The invention 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. By means of the arrangement, the situation that the automatic injection device is replaced after mistaken pricking can be avoided, and energy waste can be reduced.

Description

Technical Field

[0001] The present application belongs to the technical field of medical devices, and more specifically, to an automatic injection device. Background Art

[0002] In the medical industry, in order to prevent cross infection, disposable injection devices are becoming more and more popular among patients and medical staff and are widely used.

[0003] At present, disposable injection devices on the market usually include a housing, a syringe and a needle protection mechanism, and the syringe and the needle protection mechanism are both arranged on the housing, and the needle protection mechanism is used to be set outside the needle of the syringe. During the use of the injection device, the needle can be inserted into the injection site first, and the needle protection mechanism retracts into the housing of the injection device under the reaction force of the injected site. Then, the liquid medicine is injected into the injected site through the syringe. Finally, the needle is pulled out of the injected site, and the needle protection mechanism is directly reset and extended out of the housing to cover the needle, and is locked relative to the housing. In this way, under the locking action of the needle protection mechanism and the housing, the needle cannot be used again, thereby realizing the disposable performance of the injection device. It can be understood that the disposable injection device on the market, after the needle is inserted into the injected site and pulled out, the injection device is immediately locked and self-destructed, and cannot be used again, so as to achieve the disposable performance.

[0004] However, when the injection device is used for injection of antibody drugs, weight loss drugs, diabetes, cardiovascular and cerebrovascular diseases, etc., the injection device is usually used by the patient himself. Since the patient is not a professional medical person, when using the injection device for injection, it is very likely that the needle will not be inserted into the appropriate position of the injection site due to lack of skill or the needle will be pulled out by mistake before the medicine is injected. It is also possible that the patient will have a stress reaction due to fear and try to break free from the needle.

[0005] When the injection device is used on infants and young children, they are prone to have a stress reaction due to fear and struggle to break free from the needle.

[0006] As mentioned above, during the process of the needle of the injection device being inserted into the injection site, the patient may not be mentally prepared and may have a stress reaction, or the needle may not be inserted into the appropriate position of the injection site, and the needle needs to be pulled out from the injection site; the needle may also be pulled out by mistake before injection. In this way, the injection device cannot be used again due to premature locking, and a new injection device needs to be replaced, which wastes the injection device and the medicine in the syringe, causing economic losses. Therefore, there is an urgent need for a disposable automatic injection device that can be inserted twice without locking in the case of mistaken insertion. Summary of the invention

[0007] One of the purposes of the embodiments of the present application is to provide an automatic injection device, aiming to solve the technical problem in the prior art that after the needle is pulled out without injection, the injection device self-destructs and the injection device needs to be replaced, resulting in energy waste.

[0008] In order to solve the above technical problems, the technical solution adopted in the embodiment of the present application is:

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

[0010] a housing connected to the cartridge;

[0011] The plunger rod is used to drive the liquid medicine in the cartridge toward the distal end; the plunger rod comprises a rod body and a stopper elastically disposed on the rod body, the outer shell is sleeved outside the rod body, and the stopper is configured to abut against the outer shell toward the distal end;

[0012] A first elastic member, used for applying an elastic force toward the distal end of the rod body to drive the rod body for injection;

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

[0014] The injection button is axially movable on the housing; when the first switch is in the closed state, the injection button abuts against the first switch toward the distal end and is spaced apart from the limiting member; when the first switch is in the open state, the injection button avoids relative to the first switch and can move toward the distal end under external force to drive the limiting member to detach from the housing.

[0015] In one embodiment, the automatic injection device further comprises a pen cap, which is used to detachably cover the needle and is also used to sterilize the needle.

[0016] In one embodiment, the pen cap comprises:

[0017] A cap body, at least partially used to detachably cover the needle;

[0018] A disinfection device is arranged on the cap body and is used to disinfect the needle when the cap body covers the needle;

[0019] The second switch is arranged on the cap body, is electrically connected to the disinfection device, and is at least used for the disinfection device.

[0020] In one embodiment, the stopper comprises a first elastic arm and a barb disposed on the first elastic arm, the first elastic arm is disposed on the rod body, the barb is configured to hook the housing toward the distal end, and the injection button can squeeze the barb;

[0021] And / or, the first elastic member includes a spring sheet disposed on the rod body, the spring sheet is configured to abut against the housing toward the distal end, and the injection button can squeeze the spring sheet.

[0022] In one embodiment, the injection button and the shell are socketed with each other, and either one of the injection button and the shell is provided with a slide groove extending along the axial direction, and the other is provided with a first guide rail, and the first guide rail is slidably arranged in the slide groove; the injection button has a first extrusion portion, and the first extrusion portion and the limit member are arranged opposite to each other along the axial direction.

[0023] In one embodiment, the housing includes a shell and a fixing member assembled in the shell, the cartridge is fixed in the shell, the fixing member is sleeved outside the rod, and the limiting member can abut the fixing member toward 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 housing and the fixing member define an annular groove, and the first annular portion is axially movable in the annular groove; the first switch member is axially rotatable on the housing and / or the fixing member, and can rotate alternately to an open state and a closed state, and at least a portion of the first switch member is arranged in the annular groove;

[0025] When the first switch member is in the closed state, the first annular portion abuts against the first switch member toward the distal end; when the first switch member is in the open state, the first annular portion avoids relative to the first switch member and can move toward the distal end; the first extrusion portion can extrude the limiting member toward the distal end to make the limiting member detach from the fixing member.

[0026] In one embodiment, the first switch component includes a limit ring, which is rotatably disposed in the annular groove and is axially opposite to the first annular portion; either the limit ring or the first annular portion is provided with a convex portion, and the other is provided with a avoidance groove; when the first switch component is in the open state, the convex portion is configured to be axially opposite to the avoidance groove so that the button body can move toward the distal end under external force; when the first switch component is in the closed state, the convex portion is configured to enable the first annular portion to be limited toward the distal end.

[0027] In one embodiment, the protrusion has an elastic hook, and the elastic hook is configured to be engaged in the avoidance groove after the first extrusion portion extrudes the limiter.

[0028] In one embodiment, the automatic injection device further comprises a protective sleeve, the outer shell is sleeved on the outside of the cartridge, the protective sleeve is sleeved between the cartridge and the outer shell, and can move axially to be retracted into the outer shell or extended out of the distal end of the outer shell; the proximal end of the protective sleeve has a second elastic arm, and the distal end of the first switch element has a third elastic arm; under the condition that the protective sleeve is retracted into the outer shell, the third elastic arm is configured to squeeze the second elastic arm during the process of the first switch element switching to the on state; under the condition that the protective sleeve extends out of the distal end of the outer shell, the third elastic arm is configured to press the second elastic arm toward the distal end in the on state.

[0029] In one embodiment, the auto-injection device further includes a third elastic member configured to apply an elastic force towards the distal end to the protective sleeve, so that the protective sleeve extends out of the distal end of the housing and covers the needle.

[0030] The beneficial effects of the auto-injection device provided by the embodiments of the present application are as follows:

[0031] For the auto-injection device provided by the embodiments of the present application, during use, after the needle penetrates into the injection site, the first switch member can be first driven to the open state, and then the injection button is pressed, so that the injection button moves towards the distal end to drive the limiting member to disengage from the housing. At this time, the rod body moves towards the distal end under the elastic force of the first elastic member to drive the liquid medicine in the cartridge, thereby completing the injection work. Moreover, the limiting member disengages from the housing, and the rod body drives the liquid medicine in the cartridge towards the distal end under the elastic force of the first elastic member. In this way, the rod body cannot move towards the proximal end again, making the auto-injection device unusable again. Thus, through the design of the plunger rod and the housing, the disposable use performance of the auto-injection device is realized. After the needle penetrates into the injection site, when the patient has a stress reaction without being mentally prepared, or the needle does not penetrate into the accurate injection position of the injection site, the first switch member can be maintained in the closed state. At this time, the injection button abuts against the first switch member towards the distal end. In this way, the injection button cannot move towards the distal end, that is, the injection button cannot drive the limiting member to disengage from the housing, and the plunger rod is fixed relative to the housing through the limiting member. Thus, the needle can be pulled out from the injection site, and after adjusting the specific injection position or the patient's mental preparation, the first switch member can be adjusted to the open state to perform the injection work. Therefore, the situation of replacing the auto-injection device after accidental puncture is avoided, which helps to reduce energy waste. Description of the Drawings

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0033] Figure 1 Partial perspective schematic view of the auto-injection device provided by the embodiments of the present application in the initial state;

[0034] Figure 2 is Figure 1 exploded view of;

[0035] Figure 3 is Figure 1 cross-sectional view of;

[0036] Figure 4 is Figure 3 A partial enlarged view of

[0037] Figure 5 for Figure 1 A partial schematic diagram of the automatic injection device provided when the first switch member is in an on state;

[0038] Figure 6 for Figure 5 A cross-sectional view of

[0039] Figure 7 for Figure 6 A partial enlarged view of

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

[0041] Fig. 9 for Figure 8 A schematic diagram of the automatic injection device after the needle is removed is provided;

[0042] Fig.10 for Figure 1 Partial indication Figure 1 ;

[0043] Fig.11 A three-dimensional schematic diagram of a fixing member of an automatic injection device provided in an embodiment of the present application;

[0044] Fig.12 A three-dimensional schematic diagram of a first shell of an automatic injection device provided in an embodiment of the present application;

[0045] Fig.13 A three-dimensional schematic diagram of an injection button of an automatic injection device provided in an embodiment of the present application;

[0046] Fig.14 A three-dimensional schematic diagram of a plunger rod of an automatic injection device provided in an embodiment of the present application;

[0047] Fig.15 A three-dimensional schematic diagram of a first switch member of an automatic injection device provided in an embodiment of the present application;

[0048] Fig.16 for Fig.15 A three-dimensional schematic diagram of the first switch member cooperating with the injection button is provided;

[0049] Fig.17 for Fig.16 The enlarged view of point A in the middle;

[0050] Fig.18 for Figure 1 Partial indication Figure 2 ;

[0051] Fig.19 for Figure 8 A partial perspective schematic diagram of the automatic injection device shown;

[0052] Fig. 20 for Fig. 9 A partial perspective schematic diagram of the automatic injection device shown;

[0053] Fig.21 A three-dimensional schematic diagram of a protective cover of an automatic injection device provided in an embodiment of the present application;

[0054] Fig. 22 for Fig. 9 A partial enlarged view of

[0055] Fig.23 A three-dimensional structural diagram of an automatic injection device provided in some embodiments of the present application;

[0056] Fig.24 for Fig.23 A cross-sectional view of

[0057] Fig.25 for Fig.24 A partial enlarged view of

[0058] Fig.26 for Fig.24 Enlarged view of B.

[0059] Among them, the reference numerals in the figure are:

[0060] 10-housing; 101-limiting groove; 102-sliding groove; 103-sliding groove; 104-annular groove; 11-housing; 111-first housing; 112-second housing; 1121-protrusion; 113-fixed housing; 114-fourth limiting part; 115-second guide rail; 12-fixed member; 121-first limiting part; 122-housing; 123-third annular part; 20-syringe; 21-cartridge; 22-needle; 23-plunger rod; 2301-first extrusion 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 extrusion The pressure part; 45-trigger part; 46-connecting part; 50-injection button; 501-avoidance groove; 51-first guide rail; 52-second limiting part; 53-button body; 54-first annular part; 55-first extrusion part; 5501-second extrusion surface; 56-second annular part; 60-second elastic member; 70-protective cover; 701-guide groove; 71-second elastic arm; 72-second extrusion part; 73-sleeve; 74-third limiting part; 80-third elastic member; 90-guide rod; 100-pen cap; 110-cap body; 1110-base; 1120-first cap; 11210-buckle; 1130-second cap; 11310-groove; 120-disinfection device; 130-second switch member; Y1-first axial direction; Y2-second axial direction. DETAILED DESCRIPTION

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

[0062] In the description of the present application, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0063] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the feature. In the description of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined, wherein more than two includes two.

[0064] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0065] The following is a detailed description with reference to the accompanying drawings and embodiments:

[0066] See also Figure 1 The automatic injection device provided in the embodiment of the present application has an axial direction, and the two opposite ends of the automatic injection device along the axial direction are respectively a proximal end and a distal end, wherein the proximal end refers to the end of the automatic injection device away from the injected site during the injection process, and the distal end refers to the end of the automatic injection device close to the injected site during the injection process. Figure 1 The symbol a is shown, and the far end is Figure 1 Schematic symbol b. The axial direction includes a first axial direction Y1 and a second axial direction Y2, the first axial direction Y1 and the second axial direction Y2 are both parallel to the axial direction, and the first axial direction Y1 and the second axial direction Y2 are in opposite directions, and the "proximal end" mentioned below generally refers to the first axial direction Y1, and the "distal end" generally refers to the second axial direction Y2.

[0067] For details, please refer to Figure 1 and Figure 2 The automatic injection device includes a housing 10 , a syringe 20 , a first elastic member 30 , a first switch member 40 and an injection button 50 .

[0068] like Figure 2 and Figure 3As shown, the syringe 20 includes a cartridge 21, a needle 22 and a plunger rod 23. The cartridge 21 is used to store liquid medicine, and the needle 22 is disposed at the distal end of the cartridge 21 and is in communication 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 toward the distal end in the cartridge 21 to drive the liquid medicine in the cartridge 21, thereby pressing the liquid medicine in the cartridge 21 out of the needle 22. During the injection process of the automatic injection device, the needle 22 is inserted into the injected site, which may be the arm, buttocks, waist, etc. of the human or animal body.

[0069] like Figure 3 and Figure 4 As shown, the plunger rod 23 includes a rod body 231 and a stopper 232, and the stopper 232 is elastically movable on the rod body 231. It can be understood that the stopper 232 is connected to the rod body 231 and can be elastically movable relative to the rod body 231. At least a portion 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 liquid medicine in the cartridge 21. The housing 10 is sleeved outside the rod body 231, and the stopper 232 is configured to abut the housing 10 distally. It can be understood that the stopper 232 abuts against the housing 10 distally, thereby realizing the distal limit of the plunger rod 23.

[0070] Please continue reading Figure 3 and Figure 4 The first elastic member 30 is used to apply an elastic force toward the distal end to the rod body 231 to drive the rod body 231 to move toward the distal end for injection. The first elastic member 30 can be a spring, a tension spring, a spring sheet, or other elastic structure.

[0071] Please also read Figures 1 to 4 The first switch member 40 is movably disposed 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 move to an open state or a closed state.

[0072] Please continue reading Figures 1 to 4 The injection button 50 is disposed on the housing 10 and can move axially relative to the housing 10. Optionally, the injection button 50 is disposed at the proximal end of the housing 10, so that the user can operate the injection button 50 conveniently.

[0073] When the first switch element 40 is in the closed state, Figure 3 and Figure 4As shown, the injection button 50 abuts against the first switch member 40 toward the distal end, and is spaced apart from the stop member 232. At this time, the injection button 50 cannot move toward the distal end under the limit of the first switch member 40, and cannot drive the stop member 232, so that the limit relationship between the stop member 232 and the housing 10 can be maintained at this time. In other words, at this time, the injection button 50 cannot drive the plunger rod 23, so that the plunger rod 23 cannot drive the liquid medicine in the cartridge 21 toward the distal end.

[0074] When the first switch element 40 is in the on state, Figures 5 to 9 As shown, the injection button 50 is evacuated relative to the first switch member 40. In this way, the injection button 50 can move distally under external force to drive the stopper 232, so that the stopper 232 is separated from the housing 10. That is, the injection button 50 removes the stopper relationship between the stopper 232 and the housing 10 under external force. At this time, since the first elastic member 30 applies an elastic force toward the distal end to the rod body 231, the rod body 231 can move distally under the elastic force of the first elastic member 30 and drive the liquid medicine in the cartridge 21.

[0075] It should be noted that when the stopper 232 abuts against the housing 10 toward the distal end, the first elastic member 30 is in a force storage state. When the first elastic member 30 is a spring or a spring sheet, the first elastic member 30 is in a compressed state. When the injection button 50 removes the limit relationship between the stopper 232 and the housing 10 under external force, the first elastic member 30 is reset, so that the rod 231 and the stopper 232 move toward the distal end together and separate from the injection button 50, so that the rod 231 drives the liquid medicine in the cartridge 21 toward the distal end, as shown in FIG. Figure 8 and Fig. 9 At this time, the first elastic member 30 has been restored from the power storage state to the natural state, and the limiter 232, the rod body 231 and the first elastic member 30 are all located in the housing 10. It is difficult for the first elastic member 30 to be restored to the power storage state again, and it is also difficult for the limiter 232 and the rod body 231 to move proximally to the initial state again, so that the plunger rod 23 cannot be used again. In other words, the automatic injection device cannot be used again, thereby achieving the one-time use performance of the automatic injection device. And, as Figures 6 to 9 As shown, the housing 10 is sleeved outside the rod body 231, and the injection button 50 is disposed at the proximal end of the housing 10, so that the plunger rod 23 and the first elastic member 30 are both located in the space enclosed by the housing 10 and the injection button 50. In this way, after the plunger rod 23 drives the liquid medicine in the cartridge 21, 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 disposable performance of the automatic injection device.

[0076] Based on this, when the automatic injection device provided in the embodiment of the present application is used, the needle 22 can be first inserted into the injection site. Then, the first switch 40 is driven from the closed state to the open state, such as Figures 5 to 7 Then, the injection button 50 is pressed to move the injection button 50 to the distal end, and the injection button 50 can drive the stopper 232 to separate from the housing 10, and the rod 231 moves to the distal end under the elastic force of the first elastic member 30 to drive the liquid medicine in the cartridge 21, thereby realizing the liquid medicine injection work, as shown in FIG. Figure 8 Finally, the needle 22 is pulled out from the injected site. Fig. 9 The injection button 50 drives the stopper 232 under external force, so that when the plunger rod 23 drives the liquid medicine in the cartridge 21, the plunger rod 23 and the first elastic member 30 cannot return to the initial state again, so that the automatic injection device cannot be reused, that is, the one-time use performance of the automatic injection device is achieved.

[0077] Therefore, the automatic injection device provided in this embodiment realizes the disposable performance of the automatic injection device through the design of the plunger rod 23, the housing 10 and the first switch 40. Specifically, when the first switch 40 is in the on state, the injection button 50 can drive the plunger rod 23, so that the plunger rod 23 can realize a one-time injection work, that is, to achieve the disposable effect of the automatic injection device. When the first switch 40 is in the off state, the plunger rod 23 cannot realize the injection work of the liquid medicine. Based on this, during the use of the automatic injection device, after the needle 22 is inserted into the injected part, when the patient is not mentally prepared and has a stress reaction, or the needle 22 is not inserted into the accurate injection position of the injected part, the first switch 40 can be maintained in a closed state and the needle 22 can be pulled out from the injected part. When the patient has a stress reaction to prepare himself mentally and breaks free from the needle 22, or the needle 22 is pulled out from the injected part by mistake, the first switch 40 can also be maintained in a closed state first. By maintaining the first switch 40 in the closed state, the injection button 50 can be made to abut against the first switch 40 in the distal end, so that the injection button 50 cannot move in the distal end. That is, the injection button 50 cannot drive the limiter 232 to separate from the housing 10, and the plunger rod 23 is fixed relative to the housing 10 by the limiter 232. In this way, the needle 22 can be inserted into the injection site again, so that after adjusting the specific injection position or the patient's psychological preparation, the first switch 40 is adjusted to the open state to perform the liquid medicine injection work, so that the situation that the automatic injection device needs to be replaced when performing the injection work on the same patient can be avoided, that is, the problem that the injection device cannot be used again due to premature locking and self-destruction is solved, thereby helping to reduce energy waste and injection costs. It can be understood that after the needle 22 is inserted into the injection site, the needle 22 is pulled out from the injection site before the liquid medicine is injected, and the automatic injection device will not be locked or self-destructed. At this time, the needle 22 can be inserted again. When the needle 22 is inserted into the injection site and the needle 22 is pulled out after the injection of the liquid medicine, the injection device is locked and self-destructed, and the automatic injection device cannot be used again.

[0078] In addition, the automatic injection device provided in the embodiment of the present application has a very simple structure, is easy to manufacture, and has low cost.

[0079] Among them, when the injection button 50 removes the limiting relationship between the limiting member 232 and the shell 10 under external force, and the first elastic member 30 drives the rod body 231 to drive the medicine toward the proximal end, the rod body 231 can slowly move toward the distal end under the elastic force of the first elastic member 30 to slowly drive the medicine, so that the injection work of the automatic injection device has a certain safety performance.

[0080] Alternatively, if Figure 3 , Figure 4 , Figure 6 and Figure 7 As shown, one end of the first elastic member 30 is connected to the rod body 231, and the other end abuts against the injection button 50. When the stopper 232 abuts against the housing 10, the first elastic member 30 is in a force storage state, such as Figure 3 and Figure 4 As shown; when the limiting member 232 is separated from the housing 10, the first elastic member 30 is reset and drives the rod 231 and the limiting member 232 to move distally away from the injection button 50. Since the first elastic member 30 is connected to the rod 231 and abuts against the injection button 50, the first elastic member 30 drives the rod 231 to separate from the injection button 50 distally under its own elastic action. Figure 8 and Fig. 9 As shown, in this way, the plunger rod 23 and the first elastic member 30 cannot be reset to the initial state toward the proximal end again, thereby helping to improve the effect of the one-time use of the automatic injection device.

[0081] Alternatively, if Figure 3 and Figure 4 As shown, the first elastic member 30 is limited in the rod body 231. In addition, the rod body 231 has a guide rod 90 extending along 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, which helps to achieve the guiding effect of the elastic force direction of the first elastic member 30, thereby helping the first elastic member 30 to better achieve the effect of the plunger rod 23 driving the liquid medicine in the cartridge 21 to the distal end.

[0082] Optionally, at least two limiting members 232 are provided, and at least two limiting members 232 are spaced apart and distributed on the rod body 231 ; in the initial state of the automatic injection device, at least two limiting members 232 are both distally abutted against the housing 10 .

[0083] In some embodiments, since the design of the needle 22 needs to meet the national standard GB15811-2016, the needle 22 meets the requirements of having no burrs, burrs, hooks, etc. on the needle tip.

[0084] It should be noted that the skin tissue is elastic and closely connected to each other, so that the skin tissue will not fall off at will. When the needle tip of the needle 22 pierces the skin, the skin tissue will not remain inside or on the outer surface of the needle 22 due to its elasticity.

[0085] When the needle tip of the needle 22 penetrates the skin, the skin is punctured and the muscles next to the skin are separated by the needle tip, i.e., the skin is cut by the needle 22. As the needle 22 penetrates deeper, the skin and muscles near the needle 22 are stretched open by the tube wall of the needle 22 and gathered more tightly around the needle 22, and will not enter the needle 22.

[0086] Moreover, based on the national standard GB15811-2016, the needle tip of the needle 22 has an inclined angle, and the outer surface of the needle 22 is smoothly set. Due to the elasticity of the skin tissue and the smoothness of the outer wall of the needle 22, when the needle 22 is inserted into the skin and then pulled out of the skin tissue, no skin tissue will remain on the outer surface of the needle 22.

[0087] It should also be added here that even if there is residual tissue on the outer surface of the needle 22, due to the tight connection and elasticity between the skin tissue and the tissue, when the needle 22 is inserted into the skin again, the residual tissue on the outer surface of the needle 22 will slide along the smooth outer surface of the needle 22 and be blocked outside the skin without entering the skin tissue.

[0088] Therefore, the needle 22 is designed so that the needle 22 will not contaminate the subcutaneous tissue after being inserted into the skin. Based on this, the problem of skin tissue infection can be improved when the needle 22 is pulled out from the injected part before injection and then inserted into the injected part again.

[0089] In some embodiments, the needle 22 and the cartridge 21 are integrally arranged. In addition, the syringe 20 is a prefilled syringe, and the liquid medicine in the syringe 20 is a prefilled liquid medicine, that is, the liquid medicine is filled and filled in the cartridge 21 and the needle 22 of the syringe 20 .

[0090] Specifically, when pre-filling the liquid medicine, the liquid 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 liquid medicine is filled in the cartridge 21 and the needle 22. The liquid medicine has a certain pressure, and when the plunger rod 23 moves toward the distal end, the liquid medicine will be pushed by the plunger rod 23 and injected from the needle 22.

[0091] When the needle 22 is inserted into the injection site, the medicine solution has a certain pressure, and the plunger rod 23 blocks the end of the cartridge 21 away from the needle 22, so that the skin tissue of the injection site will not enter the needle 22. In this way, after the needle 22 is pulled out from the injection site before injection, it can be inserted into the correct injection site again to avoid infection.

[0092] In addition, since the syringe 20 is a prefilled syringe, the medicine barrel 21 and the needle 22 of the syringe 20 are filled with liquid medicine, and there is no need to perform an exhaust operation before injection, and the injection operation can be performed after piercing the injection site.

[0093] In one embodiment, see Figure 2 The automatic injection device further comprises a pen cap 100 , which is used to detachably cover the needle 22 and to sterilize the needle 22 .

[0094] The pen cap 100 refers to a structure for covering the needle 22. Specifically, when the needle 22 is not yet in use, the pen cap 100 covers the needle 22, thereby achieving a protective effect on the needle 22 and solving the problem of the needle 22 accidentally injuring the user.

[0095] The pen cap 100 also has a sterilizing function. Specifically, when the pen cap 100 covers the needle 22, the needle 22 can be sterilized by the pen cap 100, thereby achieving the aseptic use effect of the needle 22.

[0096] By adopting the above technical solution, when the needle 22 is not in use, the pen cap 100 can be used to cover the needle 22. On the basis of the pen cap 100 achieving the protective effect on the needle 22, the pen cap 100 can also be used to sterilize the needle 22. After the needle 22 is inserted into the injection site, due to the patient's stress reaction and other reasons, the needle 22 is pulled out from the injection site when the medicine is not injected. The pen cap 100 can be used to cover the needle 22 again to sterilize the needle 22, and then the sterilized needle 22 is inserted into the injection site again to perform the medicine injection operation. In this way, the pen cap 100 can be used to sterilize the needle 22, which can solve the infection problem after the needle 22 is pulled out from the injection site, so that the needle 22 can be safely inserted into the injection site again after being pulled out from the injection site when the medicine is not injected, and the automatic injection device does not need to be replaced when the medicine is not injected, which can solve the problem of resource waste.

[0097] In one embodiment, please refer to Figure 2 , Figure 23 to Figure 25 The pen cap 100 includes a cap body 110, a disinfection device 120 and a second switch 130. At least a portion of the cap body 110 is used to detachably cover the needle 22. The disinfection device 120 is disposed 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 disposed on the cap body 110, is electrically connected to the disinfection device 120, and is at least used to turn on the disinfection device 120.

[0098] The cap body 110 is a structure for covering the needle 22 .

[0099] 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.

[0100] The second switch 130 refers to a switch structure for turning on the disinfection device 120. The second switch 130 may be a touch switch or a push button. Taking the second switch 130 as a push button as an example, when the cap 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 may be in the form of a soft rubber spring to facilitate the control of the second switch 130.

[0101] By adopting the above technical solution, the disinfection device 120 can be turned on by the second switch 130, so that the disinfection device 120 can disinfect the needle 22. In this way, the infection problem after the needle 22 is pulled out from the injection site can be solved, so that after the needle 22 is pulled out from the injection site when the liquid medicine is not injected, it can be safely inserted into the injection site again after disinfection to perform the liquid medicine injection operation, so that there is no need to replace the automatic injection device when the liquid medicine is not injected, which can solve the problem of waste of resources.

[0102] In some embodiments, please refer to Figure 23 to Figure 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.

[0103] In some embodiments, please refer to Figure 23 to Figure 25 The second switch 130 is disposed on the cap body 110 and exposed outside the cap body 110, so that the user can operate the second switch 130. As an example, Figure 23 to Figure 25 As shown, the second switch component 130 is located at the distal end of the disinfection device 120 and is exposed outside the distal end of the cap body 110 , which makes it convenient for the user to operate the second switch component 130 .

[0104] In some embodiments, Figure 23 to Figure 25 As shown, one side of the second switch element 130 close to the distal end is located inside the cap body 110 , which can improve the problem of the second switch element 130 being accidentally touched.

[0105] In some embodiments, the pen cap 100 further includes a battery, which is electrically connected to the disinfection device 120 and is used to supply power to the disinfection device 120 so that the disinfection device 120 can disinfect the needle 22 .

[0106] In some embodiments, the disinfection device 120 is configured to be turned off after a predetermined disinfection time. Specifically, when the pen cap 100 is working, the cap body 110 can first cover the needle 22, and then the second switch 130 can be manipulated to turn on the disinfection device 120 and disinfect the needle 22. The disinfection device 120 automatically turns off after the predetermined disinfection time, thereby stopping the disinfection of the needle 22. This configuration can reduce the waste of the disinfection device 120 on the one hand, and reduce the control work of the disinfection device 120 on the other hand.

[0107] It can be understood that the battery, the disinfection device 120, the second switch 130, etc. form an electrical circuit, and the electrical circuit is provided with a delay circuit. Through the setting of the delay circuit, the disinfection device 120 is turned off after the predetermined disinfection time. Among them, the predetermined time can be set according to actual needs.

[0108] In some embodiments, please refer to Figure 23 to Figure 25 The cap body 110 may include a base 1110 and a first cap 1120 disposed on the base 1110. The first cap 1120 is sleeve-shaped and is used to cover the needle 22. The disinfection device 120 and the second switch 130 are both disposed on the base 1110, and at least part of the disinfection device 120 is exposed to the first cap 1120, so that the ultraviolet light emitted by the disinfection device 120 can disinfect the needle 22 through the first cap 1120.

[0109] In some embodiments, please refer to Figure 23 to Figure 26 The cap body 110 may further include a second cap 1130, which is sleeved outside the first cap 1120. The second cap 1130 is used to be sleeved outside the housing 10 to form a detachable connection with the housing 10.

[0110] As an example, Fig.26 As shown, the inner wall of the second cap 1130 is provided with a groove 1131, and the outer wall of the housing 10 is provided with a protrusion 1121. When the second cap 1130 is sleeved outside the housing 10, the protrusion 1121 is snapped into the groove 1131 to achieve a detachable connection between the second cap 1130 and the housing 10.

[0111] In some embodiments, the syringe 20 may further include a needle cap 24 , which is used to detachably plug the needle 22 to seal and protect the needle 22 .

[0112] 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.

[0113] The needle cap 24 is transparent so that the ultraviolet light emitted by the disinfection device 120 can pass through the needle cap 24 , thereby achieving the disinfection of the needle 22 .

[0114] When the syringe 20 is a prefilled syringe, after the medicine is prefilled into the cartridge 21 and the needle 22 , the plunger rod 23 can then block the end of the cartridge 21 away from the needle 22 so that the medicine is filled into the cartridge 21 and the needle 22 , and the needle 22 is sealed and protected by the needle cap 24 .

[0115] In some embodiments, the first cap 1120 may 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 may drive the needle cap 24 to move, so that the needle cap 24 and the pen cap 100 are removed from the needle 22 together, which can reduce the steps of using the automatic injection device.

[0116] In some embodiments, the cap body 110 is transparent, so that it is easy to observe the working condition of the disinfection device 120 inside the cap body 110.

[0117] In one embodiment, please refer to Figure 3 , Figure 4 , Figure 8 , Figures 10 to 12 The stopper 232 includes a first elastic arm 2321 and a barb 2322. The barb 2322 is disposed on the first elastic arm 2321, and the opening formed by the barb 2322 and the first elastic arm 2321 faces the distal end. The first elastic arm 2321 is disposed on the rod body 231. Figure 3 and Figure 4 As shown, the barb 2322 hooks the housing 10 toward the distal end, realizing the abutment relationship between the limiter 232 and the housing 10. When the first switch member 40 is in the on state and the injection button 50 moves toward the distal end under the external force, the injection button 50 squeezes the barb 2322 toward the distal end, 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 housing 10, thereby realizing the effect that the limiting relationship between the limiter 232 and the housing 10 is removed, as shown in FIG. Figure 8 shown.

[0118] In another embodiment, the limiting member 232 does not include the first elastic arm 2321 and the barb 2322, but includes a spring sheet (not shown), which is disposed on the rod body 231, and the opening formed by the spring sheet and the rod body 231 faces the distal end. In the initial state, the spring sheet hooks the housing 10 toward the distal end, and when the first switch member 40 is in the on state and the injection button 50 moves toward the distal end under an external force, the injection button 50 squeezes the spring sheet toward the distal end, so that the spring sheet is separated from the housing 10, thereby achieving the effect that the limiting relationship between the limiting member 232 and the housing 10 is removed.

[0119] In another embodiment, at least two limiting members 232 are provided, at least one limiting member 232 includes the first elastic arm 2321 and the barb 2322, and at least one limiting member 232 includes the spring sheet.

[0120] In one embodiment, please refer to Fig.10 and Fig.11 The housing 10 is provided with a limiting groove 101, and the limiting member 232 is configured to be limited in the limiting groove 101 along the circumferential direction. 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 toward the distal end, and is limited in the limiting groove 101 along the circumferential direction, so that the limiting member 232 is positioned in the circumferential direction, and the limiting member 232 can be prevented from rotating relative to the housing 10. In this way, when the injection button 50 moves toward the distal end, the injection button 50 can accurately contact and squeeze the limiting member 232, so that the contact of the limiting relationship between the limiting member 232 and the housing 10 can be accurately achieved, which is conducive to the plunger rod 23 driving the liquid medicine in the cartridge 21 toward the distal end.

[0121] In one embodiment, please refer to Figures 3 to 9 , Fig.13 and Fig.14 The injection button 50 and the housing 10 are sleeved with each other; and the injection button 50 has a first extrusion portion 55, which is arranged opposite to the stopper 232 along the axial direction, and the first extrusion portion 55 is used to extrude the stopper 232 toward the distal end to release the stopper relationship between the stopper 232 and the housing 10. Please continue to read Fig.13 and Fig.14 The injection button 50 is provided with a first guide rail 51 , which is extended in the axial direction; the housing 10 is provided with a slide groove 102 , which is extended in the axial direction, and the first guide rail 51 is slidably arranged in the slide groove 102 along the axial direction.

[0122] With such arrangement, when the first switch member 40 is switched to the on state and the injection button 50 moves distally under the external force, the first guide rail 51 moves distally along the axial direction in the slide groove 102. At this time, the injection button 50 and the housing 10 are sleeved with each other, realizing radial limitation between the injection button 50 and the housing 10. The first guide rail 51 is slidably arranged in the slide groove 102, realizing circumferential limitation between the injection button 50 and the housing 10, thereby limiting the relative rotation between the injection button 50 and the housing 10. In this way, the injection button 50 can only move relative to the housing 10 along the axial direction, realizing the guiding effect when the injection button 50 moves, so that after the injection button 50 moves distally, the first extrusion portion 55 can accurately contact and extrude the limiting member 232, thereby accurately and effectively releasing the limiting relationship between the limiting member 232 and the housing 10, which is beneficial to the driving work of the plunger rod 23 on the medicine solution.

[0123] Specifically, Fig.13 As shown, the first guide rails 51 and the first pressing portions 55 are distributed at intervals.

[0124] In other embodiments, the slide groove 102 may also be opened on the injection button 50, and correspondingly, the first guide rail 51 is provided on the housing 10; or, the injection button 50 is provided with the above-mentioned slide groove 102 and the first guide rail 51 at the same time, and the housing 10 is also correspondingly provided with the above-mentioned first guide rail 51 and the slide groove 102 at the same time.

[0125] Alternatively, if Figure 4 , Fig.10 , Fig.12 and Fig.13 As shown, the proximal side of the barb 2322 or the spring sheet of the stopper 232 has a first extrusion surface 2301 for the first extrusion portion 55 to extrude, and the first extrusion surface 2301 is an inclined surface, an arc surface or a free-form surface; the distal side of the first extrusion portion 55 has a second extrusion surface 5501, and the second extrusion surface 5501 is an inclined surface, an arc surface or a free-form surface. In this way, the first extrusion portion 55 can extrude the first extrusion surface 2301 of the stopper 232 through the second extrusion surface 5501 thereon, thereby facilitating the first extrusion portion 55 to extrude the stopper 232 to detach from the housing 10, thereby releasing the limiting relationship between the stopper 232 and the housing 10.

[0126] Alternatively, if Figure 4 , Fig.10 , Fig.11 and Fig.13 As shown, the first extrusion portion 55 is axially opposite to the limiting groove 101 of the housing 10. When the first switch member 40 is switched to the on state and the injection button 50 moves distally under an external force, the first extrusion portion 55 is inserted into the limiting groove 101 distally, thereby squeezing the limiting member 232 in the limiting groove 101 out of the limiting groove 101, thereby releasing the limiting relationship between the limiting member 232 and the housing 10.

[0127] In one embodiment, please refer to Figure 2 , Figure 4 , Figure 7 , Fig.11 and Fig.13 A second elastic member 60 is provided between the housing 10 and the injection button 50, and the second elastic member 60 is used to apply an elastic force toward the proximal end to the injection button 50 so that the injection button 50 is separated from the stopper 232; it can be understood that the second elastic member 60 abuts between the housing 10 and the injection button 50. The housing 10 is provided with a first stopper 121, and the injection button 50 is provided with a second stopper 52, and the second stopper 52 is used to abut the first stopper 121 toward the proximal end, and the first stopper 121 abuts the second stopper 52 toward the distal end.

[0128] With such arrangement, on the one hand, the injection button 50 has a tendency to move distally under the action of the second elastic member 60, so that when the injection button 50 does not move distally under external force, the spacing distribution effect between the injection button 50 and the limiting member 232 can be maintained, and the problem that the limiting relationship between the limiting member 232 and the housing 10 is released by the injection button 50 when the injection button 50 is not triggered by external force can be avoided. On the other hand, when the injection button 50 moves proximally under the elastic force of the second elastic member 60, the second limiting portion 52 of the injection button 50 abuts against the first limiting portion 121 proximally, thereby achieving the limitation of the injection button 50 toward the proximal end, thereby preventing the injection button 50 from being separated from the housing 10 proximally. In this way, when it is necessary to release the limiting relationship between the limiting member 232 and the housing 10 through the injection button 50 to achieve the injection of the medicine, there is no need to additionally install the injection button 50. In this way, the axial facing effect between the injection button 50 and the limiting member 232 can be maintained, which is beneficial for the injection button 50 to accurately squeeze the limiting member 232 subsequently, thereby improving the accuracy and efficiency of the injection work of the automatic injection device. In addition, the abutment relationship between the second limiting portion 52 and the first limiting portion 121 can prevent the injection button 50 from being separated from the housing 10 from the proximal end. In this way, after the plunger rod 23 drives the medicine in the cartridge 21 toward the distal end, the problem of the user removing the injection button 50 from the housing 10 and restoring the plunger rod 23 and the first elastic member 30 to their initial states can be solved. This can further maintain the one-time use effect of the automatic injection device, thereby avoiding the problem of cross infection caused by repeated use of the automatic injection device.

[0129] The second elastic member 60 may be a spring, a tension spring, a spring sheet or other elastic structure.

[0130] In one embodiment, please refer to Figure 2 , Figure 4 , Fig.10 and Fig.11 The housing 10 includes a shell 11 and a fixing member 12, and the fixing member 12 is assembled in the shell 11; the cartridge 21 is fixed in the shell 11, and the fixing member 12 is sleeved outside the rod body 231, and the limit member 232 can abut the fixing member 12 at the distal end. The first switch member 40 is arranged on the shell 11 and / or the fixing member 12, and can rotate axially relative to the shell 11 and the fixing member 12, so as to rotate alternately to an open state and a closed state. In this way, the first switch member 40 can be alternately switched to an open state or a closed state by rotating between the shell 11 and the fixing member 12, so as to improve the switching stability of the first switch member 40.

[0131] The first switch member 40 is axially limited to the housing 11, or the first switch member 40 is axially limited to the fixing member 12, or the first switch member 40 is axially limited to the housing 11 and the fixing member 12. In this way, when the first switch member 40 rotates to the closed state, the injection button 50 abuts against the first switch member 40 toward the distal end, thereby indirectly achieving the effect of limiting the injection button 50 toward the distal end relative to the housing 10.

[0132] Specifically, Fig.11 As shown, the limiting groove 101 is formed on the fixing member 12 .

[0133] Specifically, Figure 4 As shown, the second elastic member 60 abuts between the fixing member 12 and the injection button 50 .

[0134] See also Fig.13 The injection button 50 further includes a button body 53 .

[0135] Specifically, Figure 4 and Fig.13 As shown, the first guide rail 51 and the first pressing portion 55 are spaced apart from the button body 53. The end of the second elastic member 60 axially away from the housing 10 abuts against the button body 53. In addition, the end of the first elastic member 30 axially away from the rod 231 also abuts against the button body 53.

[0136] Please also read Figure 4 and Fig.13 The injection button 50 further includes a first annular portion 54 and the first extrusion portion 55. The first annular portion 54 is disposed on the button body 53, and the first extrusion portion 55 is disposed inside the first annular portion 54. The first extrusion portion 55 is used to extrude the limiting member 232 toward the distal end to drive the limiting member 232 to separate from the fixing member 12, thereby releasing the limiting relationship between the limiting member 232 and the fixing member 12. Figure 4 and Fig.10 As shown, an annular groove 104 is provided between the housing 11 and the fixing member 12, and the first annular portion 54 is provided in the annular groove 104, and the first annular portion 54 can move axially relative to the fixing member 12. At least part of the first switch member 40 is provided in the annular groove 104, and is axially opposite to the first annular portion 54. When the first switch member 40 is in the closed state, as shown in FIG. Figure 4 As shown, the first annular portion 54 abuts against the first switch member 40 toward the distal end, thereby indirectly limiting the first extrusion portion 55 toward the distal end, so that the first extrusion portion 55 cannot drive the limiting member 232 toward the distal end under external force. Figure 7As shown, the first annular portion 54 is evacuated relative to the first switch member 40 and can move distally, so that the first extrusion portion 55 extrudes the limiting member 232 distally, thereby releasing the limiting relationship between the limiting member 232 and the fixing member 12.

[0137] The first annular portion 54 is disposed in the annular groove 104 , and the first annular portion 54 is radially limited between the inner circumference of the housing 11 and the outer circumference of the fixing member 12 , which helps to achieve axial movement of the first annular portion 54 .

[0138] Specifically, Figure 4 , Figure 7 , Fig.11 and Fig.13 As shown, the first limiting portion 121 is disposed on the outer circumference of the fixing member 12, and the second limiting portion 52 is disposed on the inner circumference of the first annular portion 54. Of course, in other embodiments, the first limiting portion 121 can also be disposed on the inner circumference of the housing 11, and correspondingly, the second limiting portion 52 is disposed on the outer circumference of the first annular portion 54.

[0139] Specifically, Fig.13 and Fig.14 As shown, the first guide rail 51 is provided on the outer circumference of the first annular portion 54, and the slide groove 102 is provided on the inner circumference of the housing 11. In other embodiments, when the injection button 50 is provided with the slide groove 102, the slide groove 102 is provided on the outer circumference of the first annular portion 54; when the housing 10 is provided with the first guide rail 51, the first guide rail 51 is provided on the inner circumference of the housing 11.

[0140] Specifically, Figure 4 As shown, one end of the first elastic member 30 away from the rod body 231 and one end of the second elastic member 60 away from the fixing member 12 both abut against the button body 53 and are located in the first annular portion 54 .

[0141] Specifically, Fig.13 As shown, the injection button 50 further includes a second annular portion 56, which is disposed on the button body 53, the first annular portion 54 is disposed at intervals around the outer periphery of the second annular portion 56, and the first extrusion portion 55 is disposed on the second annular portion 56. Fig.11 As shown, the fixing member 12 further includes a casing 122 and a third annular portion 123 disposed in the casing 122, the first limiting portion 121 is disposed on the outer circumference of the casing 122, and the limiting groove 101 is opened in the third annular portion 123. Figure 4As shown, one end of the second elastic member 60 abutting against the fixing member 12 is sleeved between the sleeve 122 and the third annular portion 123, and one end of the second elastic member 60 abutting against 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 toward the distal end 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 squeezing the limiting member 232, thereby facilitating the effect of the plunger rod 23 driving the liquid medicine in the cartridge 21. And, as Figure 4 As shown, the outer circumference of the sleeve 122 and the inner circumference of the housing 11 define the annular groove 104 .

[0142] In one embodiment, please refer to Figure 1 , Fig.10 and Fig.15 The first switch member 40 includes a limit ring 41, which is rotatably disposed in the annular groove 104 and is axially opposite to the first annular portion 54; wherein the limit ring 41 is radially limited to the inner circumference of the housing 11 and the outer circumference of the fixing member 12. The limit ring 41 is provided with a convex portion 42, and the first annular portion 54 is provided with a avoidance groove 501. When the first switch member 40 is in the closed state, the convex portion 42 is configured to limit the first annular portion 54 toward the distal end, specifically, as Figure 4 As shown, the convex portion 42 and the avoidance groove 501 are staggered in the circumferential direction, and the convex portion 42 is held against the first annular portion 54, so that the injection button 50 is limited to the distal end relative to the housing 10, so that the injection button 50 cannot be pressed to the distal end by the first pressing portion 55 under external force. When the first switch member 40 is in the on state, the convex portion 42 and the avoidance groove 501 are axially opposite, and the injection button 50 can move to the distal end under external force, so that the first pressing portion 55 presses the limiter 232 to the distal end to release the limiter 232 and the fixing member 12. At this time, the convex portion 42 is inserted into the avoidance groove 501, so that the first pressing portion 55 can press the limiter 232.

[0143] The limiting ring 41 is axially limited at the housing 11 , or the limiting ring 41 is axially limited at the fixing member 12 , or the limiting ring 41 is axially limited at the housing 11 and the fixing member 12 .

[0144] In another embodiment, the convex portion 42 is provided on the first annular portion 54, and the avoidance groove 501 is correspondingly provided on the limiting ring 41. Alternatively, in other embodiments, the limiting ring 41 is provided with the convex portion 42 and the avoidance groove 501, and the first annular portion 54 is also provided with the avoidance groove 501 and the convex portion 42.

[0145] Specifically, Fig.10 , Fig.14 and Fig.15 As shown, the housing 11 is provided with a sliding groove 103, and the sliding groove 103 and the sliding groove 102 are spaced apart. The first switch member 40 also includes 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 housing 11, so that it is convenient for the user to trigger it so that the limiting ring 41 rotates to an open state or a closed state. The connecting portion 46 is axially limited in the sliding groove 103 to indirectly achieve the axial limitation of the limiting ring 41 relative to the housing 11 and the fixing member 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 achieving the rotation effect of the limiting ring 41 relative to the housing 11 and the fixing member 12.

[0146] In one embodiment, please refer to Figures 15 to 17 The first switch member 40 is configured to be in the open state, and when the injection button 50 removes the abutment relationship between the limit member 232 and the housing 10 under external force, the first switch member 40 and the injection button 50 are relatively locked, so that the first switch member 40 cannot move again relative to the injection button 50 and the housing 10, that is, the first switch member 40 cannot be switched to the closed state again.

[0147] Specifically, Figures 15 to 17 The protrusion 42 has an elastic hook 421 , and the elastic hook 421 is configured to be engaged in the avoidance groove 501 after the first extrusion portion 55 extrudes the limiting member 232 .

[0148] 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 avoidance groove 501. At this time, when the injection button 50 moves distally under the external force, the first extrusion portion 55 extrudes the limit member 232 distally to make the limit member 232 disengage from the shell 11, and the plunger rod 23 drives the medicine in the cartridge 21 distally under the elastic force of the first elastic member 30. At the same time, the avoidance groove 501 moves axially relative to the elastic hook 421 under the drive of the injection button 50, so that the elastic hook 421 axially penetrates into the avoidance groove 501 and is engaged with the avoidance groove 501. In this way, the relative locking and fixing 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, it can prevent the first switch member 40 from switching from the open state to the closed state again. In this way, the first switch member 40 cannot be restored to the initial state, further realizing the disposable performance of the automatic injection device. Furthermore, the first switch member 40 cannot rotate again, which helps to achieve the limiting effect of the protective cover 70 involved below. For details on how to achieve the limiting effect, please refer to the description below.

[0149] Specifically, Fig.17 As shown, when the elastic hook 421 is engaged in the avoidance groove 501, the elastic hook 421 hooks the bottom wall of the avoidance groove 501 toward the distal end, which can prevent the elastic hook 421 from escaping from the avoidance groove 501, and the elastic hook 421 is also limited in the avoidance groove 501 along the circumferential direction, which can prevent the first switch component 40 from rotating again, thereby preventing the first switch component 40 from switching from the open state to the closed state.

[0150] like Fig.16 and Fig.17 As shown, each protrusion 42 includes at least two elastic hooks 421 , which helps to improve the reliability of the relative locking between the first switch member 40 and the injection button 50 . The elastic hooks 421 are provided on the limiting ring 41 .

[0151] In one embodiment, please refer to Figure 2 and Figure 3 The automatic injection device further comprises a protective sleeve 70. The housing 10 is sleeved on the cartridge 21, and the protective sleeve 70 is sleeved between the cartridge 21 and the housing 10 and can move axially relative to the cartridge 21 and the housing 10 to be retracted into the housing 10 or extended out of the distal end of the housing 10.

[0152] It is understandable that when the automatic injection device is in the initial state, such as Figure 1 and Figure 3 As shown, the protective cover 70 can extend out of the distal end of the housing 10 and be mounted on the needle 22, thereby hiding the needle 22 and preventing the needle 22 from stabbing the user as much as possible. When the automatic injection device is used, the needle 22 is first inserted into the injection site, and the protective cover 70 moves toward the proximal end under the reaction of the injection site to retract into the housing 10. At this time, the first switch 40 can be switched to the on state, as shown in FIG. Figure 6 and Figure 7 Then, the injection button 50 is driven to remove the limiting relationship between the limiting member 232 and the housing 10, and the rod 231 drives the liquid medicine in the cartridge 21 to the distal end under the elastic force of the first elastic member 30 to achieve the injection of the liquid medicine, as shown in FIG. Figure 8 As shown; finally, the needle 22 is pulled out from the injection site, and the reaction force of the injection site on the protective cover 70 is removed. At this time, the protective cover 70 can be extended out of the distal end of the housing 10 again and cover the needle 22 again to achieve the hiding of the needle 22.

[0153] Specifically, Figures 1 to 3As shown, the housing 10 includes the above-mentioned shell 11 and the fixing member 12, the shell 11 includes a first shell 111 and a second shell 112, the first shell 111 is arranged at the distal end of the second shell 112, and the first shell 111 is connected to the second shell 112. The fixing member 12 is arranged in the first shell 111, and the slide groove 102 and the sliding groove 103 are both opened in the first shell 111, and the first switch member 40 is arranged between the fixing member 12 and the first shell 111. The second shell 112 is sleeved on the cartridge 21 and connected to the cartridge 21, and the protective cover 70 is sleeved between the second shell 112 and the cartridge 21. More specifically, the shell 11 also includes a fixing shell 113, the fixing shell 113 is assembled in the second shell 112, and the cartridge 21 is penetrated through the fixing shell 113 and assembled to the fixing shell 113, thereby indirectly realizing the connection relationship between the cartridge 21 and the second shell 112.

[0154] In one embodiment, please refer to Fig.15 , Figures 18 to 20 , the proximal end of the protective sleeve 70 has a second elastic arm 71, and the distal end of the first switch member 40 has a third elastic arm 43. When the protective sleeve 70 is retracted into the housing 10, the third elastic arm 43 is configured to squeeze the second elastic arm 71 during the process of the first switch member 40 switching from the closed state to the open state, so that the third elastic arm 43 and the second elastic arm 71 are staggered with each other; when the injection is completed, when the protective sleeve 70 extends out of the distal end of the housing 10, the second elastic arm 71 is simultaneously ejected to the distal end, and after ejection, the distal end of the third elastic arm 43 abuts against the proximal end of the second elastic arm 71.

[0155] For details, please refer to Figure 3 and Fig.21 The protective sleeve 70 includes a sleeve 73 and the second elastic arm 71, the second elastic arm 71 is arranged at the proximal end of the sleeve 73, and the sleeve 73 is sleeved between the housing 10 and the cartridge 21. Specifically, the cartridge 21 is sleeved between the second shell 112 and the fixed shell 113.

[0156] Understandably, in the initial state, Figure 3 and Fig.18 As shown, the sleeve 73 extends out of the distal end of the housing 10 and covers the needle 22 to hide 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 member 40 is in a closed state, and the third elastic arm 43 and the second elastic arm 71 are staggered in the circumferential direction, that is, at this time the second elastic arm 71 and the third elastic arm 43 are not axially opposite.

[0157] When the automatic injection device is used, the needle 22 is first inserted into the injection site, and the sleeve 73 moves toward the proximal end under the reaction of the injection site and retracts into the housing 10. At the same time, the second elastic arm 71 moves toward the proximal end along with the sleeve 73 to move to the side of the third elastic arm 43; then, the first switch 40 is switched to the on state, and the third elastic arm 43 squeezes 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 FIG. Figure 5 and Figure 6 As shown, the relative avoidance of the second elastic arm 71 and the third elastic arm 43 is achieved in this way, so that after the sleeve 73 is extended out of the far end of the housing 10 again, 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 axially opposite and abutted.

[0158] Then, the injection button 50 releases the limiting relationship between the limiting member 232 and the housing 10 under the external force, so that the rod body 231 drives the liquid medicine in the cartridge 21 under the elastic force of the first elastic member 30 to complete the injection of the liquid medicine. Figure 8 and Fig.19 And, at this time, the elastic hook 421 of the first switch member 40 is engaged with the avoidance groove 501 of the injection button 50, so that the relative locking between the first switch member 40, the housing 10 and the injection button 50 is achieved, as shown in FIG. Fig.16 and Fig.17 shown.

[0159] Finally, the needle 22 is pulled out from the injection site, and the reaction force of the injection site on the sleeve 73 is removed. The sleeve 73 can be extended out of the distal end of the housing 10 again, and the needle 22 can be covered again to hide the needle 22. At the same time, the second elastic arm 71 moves toward the distal end with the sleeve 73, and moves to the distal side of the third elastic arm 43. At this time, the second elastic arm 71 and the third elastic arm 43 are both reset, and the second elastic arm 71 faces and abuts the third elastic arm 43 toward the proximal end. In this way, the protective cover 70 is limited toward the proximal end through the mutual abutment between the second elastic arm 71 and the third elastic arm 43. In this way, the protective cover 70 cannot move toward the proximal end again, so that the needle 22 cannot be exposed again. On the one hand, the needle 22 is prevented from being used again, and the disposable performance of the automatic injection device is further realized. On the other hand, after the automatic injection device is used once, the needle 22 can be prevented from stabbing the user, thereby avoiding cross infection.

[0160] It should be noted here that when the injection button 50 releases the limiting relationship between the limiting member 232 and the housing 10 under external force, the elastic hook 421 of the first switch member 40 is engaged in the avoiding groove 501 of the injection button 50, thereby realizing the relative locking between the first switch member 40, the housing 10 and the injection button 50, so that the first switch member 40 cannot move relative to the housing 10 and the injection button 50 again, thereby maintaining the abutment state of the third elastic arm 43 of the first switch member 40 against the second elastic arm 71, so that the protective cover 70 cannot be retracted into the housing 10 toward the proximal end again, and further, the needle 22 cannot be exposed from the protective cover 70 for use again, thereby realizing the disposable performance of the automatic injection device. Of course, according to actual application requirements, a side wall can also be set on the second elastic arm 71 or the third elastic arm 43. When the second elastic arm 71 and the third elastic arm 43 are in contact with each other, 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 member 40, thereby achieving relative locking between the first switch member 40, the housing 10 and the injection button 50.

[0161] It should be noted that when the switch is in the on state, when the sleeve 73 extends out of the distal end of the housing 10, the second elastic arm 71 abuts against the third elastic arm 43 of the first switch member 40 toward the proximal end to limit the movement of the protective sleeve 70 toward the proximal end, so that the needle 22 cannot be used again. When the first switch member 40 is in the off state, the third elastic arm 43 and the second elastic arm 71 are staggered along the circumferential direction, and the sleeve 73 can move axially relative to the housing 10 and the cartridge 21. Therefore, if the patient is not mentally prepared and has a stress reaction, or the needle 22 does not pierce the accurate injection position of the injection site, the needle 22 can be pulled out from the injection site and inserted into the injection site again, so that after adjusting the specific injection position or adjusting the patient's psychological preparation, the first switch member 40 can be switched to the on state and the injection of the liquid medicine can be performed.

[0162] When the protective cover 70 is retracted into the housing 10 and the first switch 40 is switched to the on state, the third elastic arm 43 moves along the outer side of the second elastic arm 71 and squeezes the second elastic arm 71, so that the second elastic arm 71 is deformed radially inward. Fig.19 Of course, according to actual application requirements, the second elastic arm 71 and the third elastic arm 43 can also be configured as follows: when the protective cover 70 is retracted into the housing 10 and the first switch 40 is switched to the on state, the third elastic arm 43 moves along the inner side of the second elastic arm 71 and squeezes the second elastic arm 71, so that the second elastic arm 71 is deformed radially outward.

[0163] Specifically, Fig.21 and Fig. 22As shown, the outer circumference of the sleeve 73 is provided with a third limiting portion 74, and the inner circumference of the second shell 112 is provided with a fourth limiting portion 114. When the first switch 40 is in the on state, the plunger rod 23 completes the injection work, and the sleeve 73 extends out of the distal end of the housing 10 again, the third limiting portion 74 abuts against the fourth limiting portion 114 toward the distal end. In this way, the second elastic arm 71 abuts against the third elastic arm 43 toward the proximal end, and the third limiting portion 74 abuts against the fourth limiting portion 114 toward the distal end, so that the axial movement of the protective sleeve 70 is realized. At this time, the protective sleeve 70 cannot move toward the proximal end again, so that the needle 22 cannot be exposed again, and the protective sleeve 70 cannot be pulled out of the distal end of the housing 10, and the needle 22 cannot be exposed either. In this way, the disposable performance of the automatic injection device can be further realized, and the needle 22 can be prevented from stabbing the user and cross infection can be avoided.

[0164] Specifically, Figure 3 and Fig.21 As shown, the third limiting portion 74 is provided with a guide groove 701, which is extended in the axial direction. Correspondingly, the inner circumference of the housing 10 is provided with a second guide rail 115, which is extended in the axial direction, and the second guide rail 115 is slidably arranged in the guide groove 701, so that it is helpful to achieve the guiding effect of the axial movement of the protective sleeve 70, thereby helping to improve the use stability of the automatic injection device. Of course, according to actual application requirements, the guide groove 701 can be opened on the inner circumference of the housing 10, and correspondingly, the second guide rail 115 is arranged on the outer circumference of the sleeve 73.

[0165] In one embodiment, please refer to Fig.15 and Fig.21 A second pressing portion 72 is provided on the side of the second elastic arm 71 facing the third elastic arm 43 , and a third pressing portion 44 is provided on the side of the third elastic arm 43 facing the second elastic arm 71 . The third pressing portion 44 is configured to move along the second pressing portion 72 to press the second elastic arm 71 .

[0166] Specifically, the second extrusion portion 72 is arranged on the side of the second elastic arm 71 radially facing the third elastic arm 43, and the third extrusion portion 44 is arranged on the side of the third elastic arm 43 radially facing the second elastic arm 71. The second extrusion portion 72 and the opposite sides of the third extrusion portion 44 are adapted to each other. In this way, in the process of the first switch member 40 switching to the on state, the third elastic arm 43 can squeeze the second extrusion portion 72 through the third extrusion portion 44 to achieve the extrusion 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 cover 70 is extended out of the distal end of the housing 10 again, it is convenient for the second elastic arm 71 to abut against the third elastic arm 43 toward the proximal end.

[0167] Specifically, the third extrusion portion 44 is a convex portion 42 provided on one side of the third elastic arm 43, and the second extrusion portion 72 is a concave portion provided on one side of the second elastic arm 71; of course, according to actual application requirements, the second extrusion portion 72 can be a convex portion 42, and correspondingly, the third extrusion portion 44 is a concave portion, as long as the relative extrusion of the second elastic arm 71 and the third elastic arm 43 can be achieved. The extrusion surface of the second extrusion portion 72 is an inclined surface, an arc surface or a free-form surface, and the extrusion surface of the third extrusion portion 44 is an inclined surface, an arc surface or a free-form 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 during the relative extrusion deformation process, so that after the subsequent sleeve 73 extends out of the distal end of the housing 10, the second elastic arm 71 and the third elastic arm 43 can face and abut each other along the axial direction.

[0168] In one embodiment, please refer to Figure 2 and Figure 3 The automatic injection device further includes a third elastic member 80 , which is used to apply an elastic force toward the distal end to the protective sleeve 70 so that the protective sleeve 70 extends out of the distal end of the housing 10 and covers the needle 22 .

[0169] It can be understood that in the initial state, the protective cover 70 extends out of the distal end of the housing 10 under the elastic action of the third elastic member 80, and is sleeved outside the needle 22, so as to achieve hiding of the needle 22, thereby preventing the needle 22 from stabbing the user as much as possible. When the automatic injection device completes the injection work and pulls the needle 22 out of the injected part, the reaction force of the injected part on the protective cover 70 is gradually removed, and the protective cover 70 gradually extends out of the distal end of the housing 10 under the elastic force of the third elastic member 80, and sleeves the needle 22 again, so as to achieve hiding of the needle 22.

[0170] The third elastic member 80 may be a spring, a tension spring, a spring sheet or other elastic structure.

[0171] When the needle 22 is inserted into the injection site, the sleeve 73 retracts into the housing 10 under the reaction force of the injection site. When the needle 22 is pulled out from the injection site, the reaction force of the injection site on the sleeve 73 is removed, and the sleeve 73 gradually extends out of the distal end of the housing 10 under the elastic force of the third elastic member 80. That is, the sleeve 73 extends out of the distal end of the housing 10 through the action of the third elastic member 80. This can avoid the phenomenon that the protective cover 70 extends out of the distal end of the housing 10 when the needle 22 is not pulled out from the injection site, causing the needle 22 to shake.

[0172] Among them, the radial and circumferential directions mentioned above are both 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 by the outer circumferential side of the plunger rod 23, and the circumferential direction is also the circumferential direction defined by the circle formed by the outer circumferential side of the plunger rod 23.

[0173] The injection device provided in the embodiment of the present application has the following working principle:

[0174] The injection device is in the initial state, such as Figure 3 , Figure 4 and Fig.18 As shown, the stopper 232 of the plunger rod 23 abuts against the housing 10 at the distal end, specifically, the barb 2322 elastically hooks the housing 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 power storage state. The first switch member 40 is in a closed state, and the convex portion 42 of the first switch member 40 is not directly opposite to the avoidance groove 501 of the injection button 50, but staggered, so that the first annular portion 54 of the injection button 50 abuts against the convex portion 42 at the distal end, thereby preventing it from moving toward the distal end. The sleeve 73 of the protective cover 70 extends out of the distal end of the housing 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 side of the second elastic arm 71 of the protective sleeve 70, and the third elastic arm 43 and the second elastic arm 71 are staggered in the circumferential direction, that is, the second elastic arm 71 and the third elastic arm 43 are not axially opposite.

[0175] When using the injection device, the needle cap 24 can be disassembled from the needle 22 first, and the needle 22 can be inserted into the injection site distally. The sleeve 73 moves toward the proximal end under the reaction of the injection site and retracts into the housing 10, so that the third elastic member 80 is in a power storage state. At the same time, the second elastic arm 71 moves toward the proximal end with the sleeve 73 to move to the side of the third elastic arm 43. At this time, the first switch member 40 is still in a closed state, and the syringe is not self-destructed or locked. In this step, when the needle 22 is not inserted into the appropriate position of the injection site, or the patient is not mentally prepared and has a stress reaction and breaks free from the needle 22, or the needle 22 is pulled out by mistake, the needle 22 can be pulled out from the injection site, and then the pen cap 100 covers the needle 22, and the second switch member 130 on the pen cap 100 is manipulated so that the disinfection device 120 of the pen cap 100 disinfects the needle 22. After the pen cap 100 has been used to sterilize the needle 22 and the needle 22 needs to be inserted into the injection site again, the pen cap 100 is removed from the needle 22. In addition, before the needle 22 is inserted into the injection site for the first time, the needle 22 can also be sterilized by the pen cap 100.

[0176] 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 directly opposite to the avoidance groove 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 toward the distal end. In the process of the first switch member 40 rotating from the closed state to the open state, the third elastic arm 43 rotates relative to the second elastic arm and squeezes 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 FIG. Figure 5 and Figure 6 In this way, the relative avoidance of the second elastic arm 71 and the third elastic arm 43 is achieved, so that after the sleeve 73 extends out of the far end of the housing 10 again, 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 axially opposite and abutted.

[0177] Then, the injection button 50 is pressed to move the injection button 50 toward the distal end, and the first extrusion portion 55 of the injection button 50 extrudes the stopper 232 toward the distal end, so that the stopper 232 is separated from the housing 10. The first elastic member 30 is reset and drives the plunger rod 23 to move toward the distal end, so that the plunger rod 23 pushes the liquid medicine toward the distal end, thereby achieving liquid medicine injection. Figure 8 and Fig.19 Moreover, at this time, the elastic hook 421 of the first switch member 40 is engaged with the avoidance groove 501 of the injection button 50, thereby achieving relative locking between the first switch member 40, the housing 10 and the injection button 50. Fig.16 and Fig.17 shown.

[0178] Finally, the needle 22 is pulled out from the injection site, and the reaction force of the injection site on the sleeve 73 is removed, so that the sleeve 73 can be extended out of the distal end of the housing 10 again under the action of the third elastic member 80, and the needle 22 is again covered to achieve the hiding of the needle 22. At the same time, the second elastic arm 71 moves toward the distal end with the sleeve 73, and moves to the distal side of the third elastic arm 43. At this time, the second elastic arm 71 and the third elastic arm 43 are both reset, and the second elastic arm 71 is facing and abutting the third elastic arm 43 toward the proximal end. In this way, the protective cover 70 is limited toward the proximal end through the mutual abutment of the second elastic arm 71 and the third elastic arm 43, so that the protective cover 70 cannot move toward the proximal end again, and the needle 22 cannot be exposed again. Thereby, the locking and self-destruction effect of the automatic injection device is achieved.

[0179] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. An automatic injection device having an axial direction, wherein two opposite ends of the automatic injection device along the axial direction are respectively a proximal end and a distal end; the automatic injection device comprises a cartridge and a needle disposed at the distal end of the cartridge, It is characterized in that The automatic injection device further comprises: a housing connected to the cartridge; The plunger rod is used to drive the liquid medicine in the cartridge toward the distal end; the plunger rod comprises a rod body and a stopper elastically disposed on the rod body, the outer shell is sleeved outside the rod body, and the stopper is configured to abut against the outer shell toward the distal end; A first elastic member, used for applying an elastic force toward the distal end of the rod body to drive the rod body to perform injection; A first switch member is movably disposed on the housing to switch between an open state and a closed state; An injection button is axially movable on the housing; when the first switch is in a closed state, the injection button abuts against the first switch toward the distal end and is spaced apart from the limiting member; when the first switch is in an open state, the injection button is evacuated relative to the first switch and can move toward the distal end under an external force to drive the limiting member to detach from the housing.

2. The automatic injection device according to claim 1, It is characterized in that The automatic injection device further comprises a pen cap, which is used to detachably cover the needle and to sterilize the needle.

3. The automatic injection device according to claim 2, It is characterized in that The pen cap comprises: A cap body, at least partially used to detachably cover the needle; A disinfection device, disposed on the cap body and used for disinfecting the needle when the cap body covers the needle; The second switch is arranged on the cap body, is electrically connected to the disinfection device, and is at least used to turn on the disinfection device.

4. The automatic injection device according to claim 1, It is characterized in that The stopper comprises a first elastic arm and a barb disposed on the first elastic arm, wherein the first elastic arm is disposed on the rod body, the barb is configured to hook the housing toward the distal end, and the injection button can squeeze the barb; And / or, the first elastic member includes a spring sheet provided on the rod body, the spring sheet is configured to abut against the housing toward the distal end, and the injection button can squeeze the spring sheet.

5. The automatic injection device according to claim 1, It is characterized in that The injection button and the shell are socketed with each other, and either one of them is provided with a slide groove extending along the axial direction, and the other is provided with a first guide rail, and the first guide rail is slidably arranged in the slide groove; the injection button has a first extrusion portion, and the first extrusion portion and the limit member are arranged opposite to each other along the axial direction.

6. The automatic injection device according to any one of claims 1 to 5, It is characterized in that 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 outside the rod, and the limiting member can abut against the fixing member toward the distal end; The injection button comprises a button body, a first annular portion provided on the button body, and a first extrusion portion provided in the first annular portion; the housing and the fixing member define an annular groove, and the first annular portion is axially movable in the annular groove; the first switch member is axially rotatable on the housing and / or the fixing member, and can alternately rotate to the open state and the closed state, and at least a portion of the first switch member is provided in the annular groove; When the first switch member is in the closed state, the first annular portion distally abuts against the first switch member; when the first switch member is in the opened state, the first annular portion avoids relative to the first switch member and can move distally; the first extrusion portion can extrude the limiting member distally to separate the limiting member from the fixing member.

7. The automatic injection device according to claim 6, It is characterized in that The first switch component includes a limit ring, which is rotatably disposed in the annular groove and is axially opposite to the first annular portion; either the limit ring or the first annular portion is provided with a convex portion, and the other is provided with a avoidance groove; when the first switch component is in the open state, the convex portion is configured to be axially opposite to the avoidance groove so that the button body can move toward the distal end under external force; when the first switch component is in the closed state, the convex portion is configured to limit the first annular portion toward the distal end.

8. The automatic injection device according to claim 7, It is characterized in that The convex portion has an elastic hook, and the elastic hook is configured to be engaged in the avoidance groove after the first extrusion portion squeezes the limit member.

9. The automatic injection device according to any one of claims 1 to 5, It is characterized in that The automatic injection device further comprises a protective sleeve, the outer shell is sleeved on the outside of the cartridge, the protective sleeve is sleeved between the cartridge and the outer shell, and can move axially to be retracted into the outer shell or extended out of the distal end of the outer shell; The proximal end of the protective sleeve has a second elastic arm, and the distal end of the first switch element has a third elastic arm; Under the condition that the protective cover is retracted into the housing, the third elastic arm is configured to squeeze the second elastic arm during the process of the first switch element switching to the on state; Under the condition that 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 toward the distal end in the open state.

10. The automatic injection device according to claim 9, It is characterized in that The automatic injection device further comprises a third elastic member, and the third elastic member is used to apply an elastic force toward the distal end to the protective sleeve, so that the protective sleeve extends out of the distal end of the shell and covers the needle.

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