Automatic injection pen

Abstract

The utility model relates to the technical field of medical instruments, and discloses an automatic injection pen which comprises a shell, a bracket and an injector, the shell is provided with an opening, the bracket is arranged in the shell, the injector is fixedly arranged on the bracket, the bracket is provided with a first position and a second position, and a plurality of positioning blocks are arranged on the inner wall of the shell. The multiple positioning blocks are arranged at intervals and annularly distributed around the axis of the injector, a positioning groove is defined by every two adjacent positioning blocks, and the bracket is provided with a first positioning part and a second positioning part; when the automatic injection pen is not used, the bracket is located at the first position, the first positioning part makes contact with the positioning block, the first positioning part can penetrate through the positioning groove under the action of the propelling mechanism, at the moment, the syringe needle is located in the shell, and potential safety hazards can be reduced; when the automatic injection pen is used, the pushing mechanism drives the bracket to move from the first position to the second position, when the bracket is located at the second position, the second positioning part makes contact with the positioning block, the bracket is stably arranged at the second position, and at the moment, a syringe needle stretches out of the opening.

Description

Technical Field

[0001] The utility model relates to the technical field of medical equipment, in particular to an automatic injection pen. Background Art

[0002] An automatic injection pen includes a shell, in which a syringe and a propulsion mechanism are arranged, and the propulsion mechanism pushes the piston in the syringe to realize automatic injection. In the related art, a bracket is also provided in the shell, and the syringe is arranged on the bracket, and the bracket has a first position and a second position. When the automatic injection pen is not in use, the bracket is in the first position and the needle of the syringe is located in the shell. When the automatic injection pen is in use, the propulsion mechanism pushes the bracket to move from the first position to the second position to make the needle of the syringe extend out of the shell, and then pushes the piston in the syringe to move. In the automatic injection pen of this structure, when it is not in use, the needle of the syringe is located in the shell, which can reduce safety hazards. To achieve this effect, the bracket needs to be fixed in the shell in a movable manner and be located in the first position, and after it moves to the second position, it needs to be stably arranged to avoid the syringe from moving during the injection. Utility Model Content

[0003] The purpose of the utility model is to provide an automatic injection pen which can reduce potential safety hazards when not in use.

[0004] In order to achieve the above-mentioned object, the utility model provides an automatic injection pen, comprising a shell, a propulsion mechanism, a bracket and a syringe, wherein the shell has an opening, the propulsion mechanism is arranged on the shell, the bracket is arranged in the shell, the syringe is fixedly arranged on the bracket, the bracket has a first position and a second position, the propulsion mechanism is used to push the bracket to move from the first position toward the opening to the second position, and to push the piston of the syringe to move toward the opening; wherein a positioning block is provided on the inner wall of the shell, and the positioning block is provided in plurality, the plurality of the positioning blocks are arranged at intervals and arranged in a ring shape around the axis of the syringe, a positioning groove is defined between two adjacent positioning blocks, the bracket has a first positioning portion and a second positioning portion, and the second positioning portion is located on a side of the first positioning portion away from the opening;

[0005] When the bracket is located at the first position, the first positioning portion contacts two adjacent positioning blocks, and the first positioning portion can pass through the corresponding positioning groove under the action of the propulsion mechanism, and the needle of the syringe is located in the shell; when the bracket is located at the second position, the second positioning portion contacts at least one positioning block, and the needle of the syringe extends out of the opening.

[0006] In a specific embodiment of the utility model, the bracket also has a connecting portion, the first positioning portion and the second positioning portion are arranged along the axial direction of the syringe, the first positioning portion is connected to the bracket, and the connecting portion connects the first positioning portion and the second positioning portion, and in the arrangement direction of the positioning block, the length of the positioning groove is greater than the length of the connecting portion.

[0007] In a specific embodiment of the utility model, the first positioning portion includes a first positioning foot, a second positioning foot and a first clamping block, the first positioning foot and the second positioning foot are both connected to one end of the connecting portion away from the second positioning portion, and the two are arranged at intervals, and the side of the first positioning foot away from the second positioning foot and the side of the second positioning foot away from the first positioning foot are both connected to the first clamping block;

[0008] When the bracket is located at the first position, the first clamping block on the first positioning foot and the second positioning foot is detachably clamped with two adjacent positioning blocks respectively.

[0009] In a specific embodiment of the present invention, the second positioning portion includes a positioning platform, the positioning platform is connected to the bracket, and in the arrangement direction of the positioning blocks, the length of the positioning platform is greater than the length of the positioning slot.

[0010] In a specific embodiment of the present invention, the automatic injection pen further comprises a first reinforcing rib portion, the first reinforcing rib portion is located on a side of the positioning platform away from the first positioning portion, and the first reinforcing rib portion connects the bracket and the positioning platform.

[0011] In a specific embodiment of the present invention, the bracket further comprises a mounting portion, wherein the mounting portion is provided with a plurality of mounting portions arranged circumferentially, and the mounting portions are in contact with the inner wall of the shell.

[0012] In a specific embodiment of the present invention, the automatic injection pen further comprises a second reinforcing rib portion, wherein the second reinforcing rib portion connects the mounting portion and the bracket.

[0013] In a specific embodiment of the utility model, the automatic injection pen further comprises a protective sleeve and an elastic member, wherein the protective sleeve is movably connected to an end of the bracket close to the opening, and the protective sleeve partially extends outside the opening, and the needle of the syringe extends into the protective sleeve, and the elastic member connects the protective sleeve and the bracket to fix the protective sleeve;

[0014] When the protective cover is subjected to force, the protective cover can be retracted away from the opening.

[0015] In a specific embodiment of the utility model, the automatic injection pen further comprises a second card block, which is arranged on the inner wall of the shell and located at one end of the shell close to the opening;

[0016] The outer wall of the protective sleeve is also provided with a strip-shaped card slot, the length direction of which is parallel to the axial direction of the syringe, and in the axial direction of the syringe, the length of the card slot is greater than the length of the second card block;

[0017] Wherein, when the bracket is located at the first position, the second card block is located between the card slot and the opening, and the card slot and the second card block are arranged along the axial direction of the syringe, and the second card block is used to be connected to one end of the card slot close to the opening to prevent the protective sleeve from retracting back to the opening.

[0018] In a specific embodiment of the present invention, the automatic injection pen further comprises a protective cap, which is detachably connected to the housing and covers the opening.

[0019] Compared with the prior art, the automatic injection pen of the present utility model has the following beneficial effects:

[0020] The automatic injection pen of the embodiment of the utility model has a bracket located at the first position when not in use, and its first positioning portion is in contact with the positioning block, and the first positioning portion can pass through the corresponding positioning groove under the action of the pushing mechanism, that is, the bracket is fixed in the shell in a movably manner and is located in the first position, at which time the needle of the syringe is located in the shell; when the automatic injection pen is in use, the pushing mechanism drives the bracket to move from the first position to the second position, and when the bracket is in the second position, the second positioning portion is in contact with the positioning block, based on which the bracket is stably arranged in the second position, at which time the needle of the syringe extends out of the opening. In summary, since the needle of the syringe is located in the shell when the automatic injection pen is not in use, safety hazards can be reduced; in addition, by arranging a positioning block in the shell to position the first position and the second position of the bracket, the positioning block can strengthen the strength of the shell. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a structural diagram of the automatic injection pen of the utility model embodiment;

[0022] Figure 2 It is a cross-sectional structural diagram of the automatic injection pen when the bracket of the embodiment of the utility model is located at the first position;

[0023] Figure 3 It is a cross-sectional structural diagram of the automatic injection pen when the bracket of the embodiment of the utility model is located at the second position;

[0024] Figure 4This is a structural diagram of the cooperation between the bracket and the protective cover in the embodiment of the utility model;

[0025] Figure 5 It is a structural diagram of the housing of the embodiment of the utility model;

[0026] Figure 6 It is a structural diagram of the cooperation between the first positioning part and the positioning platform when the bracket of the embodiment of the utility model is located at the first position;

[0027] Figure 7 It is a structural diagram of the cooperation between the second positioning portion and the positioning platform when the bracket of the embodiment of the utility model is located at the second position;

[0028] Figure 8 This utility model embodiment Figure 3 A is an enlarged schematic diagram.

[0029] In the figure, 1, shell; 101, opening; 11, second clamping block; 2, propulsion mechanism; 3, bracket; 31, first positioning part; 311, first positioning foot; 312, second positioning foot; 313, first clamping block; 32, second positioning part; 321, positioning platform; 33, connecting part; 34, first reinforcing rib part; 35, mounting part; 36, second reinforcing rib part; 4, syringe; 41, cap; 5, positioning block; 501, positioning groove; 6, protective sleeve; 601, clamping slot; 7, elastic member; 8, protective cap; 81, clamping body. DETAILED DESCRIPTION

[0030] The following is a further detailed description of the specific implementation of the present invention in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0031] like Figure 1-8As shown, an automatic injection pen according to an embodiment of the utility model comprises a housing 1, a propulsion mechanism 2, a bracket 3 and a syringe 4, wherein the housing 1 has an opening 101, the propulsion mechanism 2 is arranged on the housing 1, the bracket 3 is arranged in the housing 1, the syringe 4 is fixedly arranged on the bracket 3, the bracket 3 has a first position and a second position, the propulsion mechanism 2 is used to push the bracket 3 to move from the first position toward the opening 101 to the second position, and to push the piston of the syringe 4 to move toward the opening 101; wherein the inner wall of the housing 1 is provided with a positioning block 5, and the positioning block 5 is provided with a plurality of The positioning blocks 5 are spaced apart and arranged in a ring shape around the axis of the syringe 4, a positioning groove 501 is defined between two adjacent positioning blocks 5, the bracket 3 has a first positioning portion 31 and a second positioning portion 32, the second positioning portion 32 is located on the side of the first positioning portion 31 away from the opening 101; when the bracket 3 is located at the first position, the first positioning portion 31 contacts with two adjacent positioning blocks 5, and the first positioning portion 31 can pass through the corresponding positioning groove 501 under the action of the propulsion mechanism 2, and when the bracket 3 is located at the second position, the second positioning portion 32 contacts with at least one positioning block 5.

[0032] Specifically, when the automatic injection pen of this embodiment is not in use, the bracket 3 is located at the first position, and its first positioning portion 31 is in contact with the positioning block 5, and the first positioning portion 31 can pass through the corresponding positioning groove 501 under the action of the propulsion mechanism 2, that is, the bracket 3 is fixed in the shell 1 in a movably manner and is located in the first position. At this time, the needle of the syringe 4 is located in the shell 1; when the automatic injection pen is in use, the bracket 3 is driven by the pushing mechanism to move from the first position to the second position, and when the bracket 3 is in the second position, the second positioning portion 32 is in contact with the positioning block 5, based on this, the bracket 3 is stably arranged in the second position, and at this time, the needle of the syringe 4 extends out of the opening 101. In summary, since the needle of the syringe 4 is located in the shell 1 when the automatic injection pen is not in use, safety hazards can be reduced; in addition, by arranging the positioning block 5 in the shell 1 to position the first position and the second position of the bracket 3, the positioning block 5 can strengthen the strength of the shell 1.

[0033] The pushing mechanism includes a button, a plunger and a spring. The housing 1 has an installation port, which is arranged opposite to the opening 101. The plunger is clamped in the housing 1. The button is arranged at the installation port. The spring is arranged in the housing 1 and connects the housing 1 and the plunger, and the spring is in a compressed state. In actual application, pressing the button can make the plunger disengage from the clamping state with the housing 1. Thereafter, the spring drives the plunger to move axially along the syringe 4. The plunger includes a column and a pusher. The pusher is detachably connected to the column. The pusher pushes the bracket 3 from the first position to the second position. When the bracket 3 is fixed in the second position, the pusher is separated from the column, and then the column moves in the syringe and pushes the piston, thereby completing the injection. Specifically, the pusher is detachably clamped on the column.

[0034] In this embodiment, if Figure 4 As shown, the bracket 3 also has a connecting portion 33, the first positioning portion 31 and the second positioning portion 32 are arranged axially along the syringe 4, the first positioning portion 31 connects the bracket 3, and the connecting portion 33 connects the first positioning portion 31 and the second positioning portion 32, that is, the first positioning portion 31 and the second positioning portion 32 that have a matching relationship with the positioning block 5 are arranged along one direction. The advantage of this structure is that it is conducive to determining the position of the second positioning portion 32 on the bracket 3, so that the second positioning portion 32 can contact the positioning block 5 when the bracket 3 is in the second position, which is convenient for design. In the arrangement direction of the positioning block 5, the length of the positioning groove 501 is greater than the length of the connecting portion 33. Based on this, when the bracket 3 moves from the first position to the second position, the connecting portion 33 can pass through the positioning groove 501.

[0035] Furthermore, the first positioning portion 31 includes a first positioning foot 311, a second positioning foot 312 and a first clamping block 313. The first positioning foot 311 and the second positioning foot 312 are both connected to one end of the connecting portion 33 away from the second positioning portion 32, and the two are arranged at intervals. The side of the first positioning foot 311 away from the second positioning foot 312 and the side of the second positioning foot 312 away from the first positioning foot 311 are both connected to the first clamping block 313. Figure 6 As shown, when the bracket 3 is located in the first position, the first clamping block 313 on the first positioning foot 311 and the second positioning foot 312 are respectively detachably clamped with the two adjacent positioning blocks 5, and since the first positioning foot 311 and the second positioning foot 312 are arranged at intervals, when the propulsion mechanism 2 pushes the bracket 3 to move from the first position to the second position, the first positioning foot 311 and the second positioning foot 312 will be deformed and move closer to each other, thereby, the first clamping block 313 will move with the first positioning foot 311 and the second positioning foot 312 and enter the positioning groove 501, at this time, the first clamping block 313 is disengaged from the clamping state with the positioning block 5, based on this, the first positioning foot 311, the second positioning foot 312 and the connecting portion 33 can pass through the positioning groove 501, so that the bracket 3 can be smoothly moved from the first position to the second position; and this structure of the first positioning portion 31 is simple in structure and can effectively ensure the layout stability of the bracket 3 when it is in the first position.

[0036] In this embodiment, if Figure 4 and Figure 7 As shown, the second positioning portion 32 includes a positioning platform 321, which is connected to the bracket 3. In the arrangement direction of the positioning block 5, the length of the positioning platform 321 is greater than the length of the positioning groove 501, that is, the positioning platform 321 cannot pass through the positioning groove 501. Based on this, the bracket 3 can be stably arranged in the second position and cannot move toward the opening 101.

[0037] Furthermore, if Figure 4As shown, the automatic injection pen also includes a first reinforcing rib portion 34, which is located on a side of the positioning platform 321 away from the first positioning portion 31, and the first reinforcing rib portion 34 connects the bracket 3 and the positioning platform 321. Specifically, the setting of the first reinforcing rib portion 34 can improve the connection strength between the positioning platform 321 and the bracket 3, and improve the structural reliability of the bracket 3.

[0038] Furthermore, if Figure 4 As shown, the bracket 3 also has a mounting portion 35, and a plurality of mounting portions 35 are arranged circumferentially. The mounting portions 35 are in contact with the inner wall of the shell 1. Based on this, the bracket 3 can be stably arranged in the shell 1, and a layout space for the first positioning portion 31, the second positioning portion 32 and the positioning block 5 can be formed between the bracket 3 and the shell 1.

[0039] Specifically, the mounting portion 35 is a block, and further, as Figure 4 As shown, the automatic injection pen further includes a second reinforcing rib portion 36 , which connects the mounting portion 35 and the bracket 3 , thereby improving the connection strength between the mounting portion 35 and the bracket 3 and improving the structural reliability of the bracket 3 .

[0040] As a preferred embodiment of the present invention, the positioning platform 321 is disposed between two adjacent mounting portions 35, and the mounting portions 35 are flush with the side of the opening 101 and the positioning platform 321 are flush with the side of the opening 101. Thus, when the bracket 3 is located at the second position, the mounting portion 35 will also contact the positioning block 5, so that the bracket 3 can be more stably arranged at the second position.

[0041] In this embodiment, if Figure 2-3As shown, the automatic injection pen also includes a protective sleeve 6 and an elastic member 7. The protective sleeve 6 is movably connected to one end of the bracket 3 close to the opening 101, and the protective sleeve 6 partially extends to the outside of the opening 101. The needle of the syringe 4 extends into the protective sleeve 6. The elastic member 7 connects the protective sleeve 6 and the bracket 3 to fix the protective sleeve 6. Specifically, a connecting groove is provided on the protective sleeve 6, and a connecting protrusion is provided on the bracket 3. In the axial direction of the syringe 4, the length of the connecting groove is greater than the length of the connecting protrusion, and the connecting protrusion is snapped into the connecting groove. One end of the protective sleeve 6 is sleeved on the bracket 3. Under the action of the elastic member 7, the protective sleeve 6 can be stably connected to the bracket 3; and when the protective sleeve 6 is subjected to force, based on the fact that the length of the connecting groove is greater than the length of the connecting protrusion, the protective sleeve 6 can retract back to the opening 101. In actual application, when an injection is required, the user presses the automatic injection pen on the site to be injected, and the protective sleeve 6 first contacts the site to be injected, and the protective sleeve 6 retracts a certain distance to ensure that the needle of the subsequent syringe 4 can be inserted into the site to be injected, and then presses the button to release the plunger. Under the action of the plunger, the bracket 3 moves from the first position to the second position. At this time, the elastic member 7 will compress and provide a reaction force to the protective sleeve 6, and the protective sleeve 6 will be pressed more tightly on the site to be injected, which can play a certain analgesic effect. In this embodiment, the elastic member 7 is a spring, which has a simple structure and is easy to use.

[0042] Furthermore, if Figure 5 As shown, the automatic injection pen further includes a second card block 11, which is disposed on the inner wall of the housing 1 and located at one end of the housing 1 close to the opening 101; Figure 4 As shown, the outer wall of the protective sleeve 6 is also provided with a strip-shaped card slot 601, and the length direction of the card slot 601 is parallel to the axial direction of the syringe 4. In the axial direction of the syringe 4, the length of the card slot 601 is greater than the length of the second card block 11; wherein, when the bracket 3 is located at the first position, the second card block 11 is located between the card slot 601 and the opening 101, and the card slot 601 and the second card block 11 are arranged along the axial direction of the syringe 4, and when the bracket 3 is located at the second position and the injection of the syringe 4 is completed, the second card block 11 is connected to the end of the card slot 601 close to the opening 101 to prevent the protective sleeve 6 from retracting back to the opening 101. Specifically, when the injection is performed, the injection site will limit the movement of the protective sleeve 6, and after the bracket 3 moves from the first position to the second position, the protective sleeve 6 and the bracket 3 will compress the elastic member 7. Therefore, when the injection is completed, the elastic member 7 will drive the protective sleeve 6 to move toward the opening 101 during the process of restoring the initial state. At this time, as shown in FIG. Figure 8As shown, the second card block 11 will be inserted into the card slot 601 and connected to the end of the card slot 601 close to the opening 101. At this time, the protective sleeve 6 is in a state of extending out of the opening 101 and is maintained, and the needle of the syringe 4 is located in the protective sleeve 6. The second card block 11 will limit the movement of the protective sleeve 6 toward the syringe 4. Based on this, even if the protective sleeve 6 is accidentally touched, it will not move toward the syringe 4, that is, the needle will not be exposed, which can avoid accidental injury to the user and reduce safety hazards.

[0043] In this embodiment, if Figure 2 As shown, the automatic injection pen also includes a protective cap 8, which is detachably connected to the shell 1 and covers the opening 101, and the protective cap 8 also includes the protective sleeve 6. The protective cap 8 can prevent foreign matter from entering the shell 1 from the opening 101, and can also prevent the protective sleeve 6 from being contaminated. In addition, in actual application, the syringe 4 also includes a cap 41, which is detachably connected to the barrel of the syringe 4 and includes the needle. Based on this, in this embodiment, the protective cap 8 has a snap-on body 81, and the snap-on body 81 is located in the protective cap 8. The snap-on body 81 is snap-on with the cap 41. When the protective cap 8 is removed from the shell 1, the protective cap 8 will take the cap 41 off together, which can reduce the steps of manually removing the cap 41 of the syringe 4, and has high safety and easy operation.

[0044] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principle of the present invention. These improvements and substitutions should also be regarded as the protection scope of the present invention.

Claims

1. An automatic injection pen, characterized in that: The invention comprises a housing (1), a propulsion mechanism (2), a bracket (3) and a syringe (4), wherein the housing (1) has an opening (101), the propulsion mechanism (2) is arranged on the housing (1), the bracket (3) is arranged in the housing (1), the syringe (4) is fixedly arranged on the bracket (3), the bracket (3) has a first position and a second position, the propulsion mechanism (2) is used to push the bracket (3) from the first position toward the opening (101) to the second position, and is used to push the syringe (4) The piston of the syringe (4) moves toward the opening (101); wherein a positioning block (5) is provided on the inner wall of the housing (1), and a plurality of the positioning blocks (5) are provided, the plurality of the positioning blocks (5) are arranged at intervals and arranged in a ring shape around the axis of the syringe (4), and a positioning groove (501) is defined between two adjacent positioning blocks (5), and the bracket (3) has a first positioning portion (31) and a second positioning portion (32), and the second positioning portion (32) is located on a side of the first positioning portion (31) away from the opening (101); When the bracket (3) is located at the first position, the first positioning portion (31) contacts two adjacent positioning blocks (5), and the first positioning portion (31) can pass through the corresponding positioning groove (501) under the action of the propulsion mechanism (2), and the needle of the syringe (4) is located in the shell (1); when the bracket (3) is located at the second position, the second positioning portion (32) contacts at least one of the positioning blocks (5), and the needle of the syringe (4) extends out of the opening (101).

2. The automatic injection pen according to claim 1, characterized in that: The bracket (3) further comprises a connecting portion (33), the first positioning portion (31) and the second positioning portion (32) are arranged axially along the syringe (4), the first positioning portion (31) is connected to the bracket (3), the connecting portion (33) is connected to the first positioning portion (31) and the second positioning portion (32), and in the arrangement direction of the positioning block (5), the length of the positioning groove (501) is greater than the length of the connecting portion (33).

3. The automatic injection pen according to claim 2, characterized in that: The first positioning portion (31) comprises a first positioning foot (311), a second positioning foot (312) and a first clamping block (313); the first positioning foot (311) and the second positioning foot (312) are both connected to one end of the connecting portion (33) away from the second positioning portion (32), and the two are arranged at intervals; the side of the first positioning foot (311) away from the second positioning foot (312) and the side of the second positioning foot (312) away from the first positioning foot (311) are both connected to the first clamping block (313); When the bracket (3) is located at the first position, the first clamping block (313) on the first positioning foot (311) and the second positioning foot (312) are respectively detachably clamped with two adjacent positioning blocks (5).

4. The automatic injection pen according to claim 2, characterized in that: The second positioning portion (32) comprises a positioning platform (321), the positioning platform (321) is connected to the bracket (3), and in the arrangement direction of the positioning blocks (5), the length of the positioning platform (321) is greater than the length of the positioning groove (501); When the bracket (3) is located at the second position, the connecting portion (33) passes through the positioning groove (501), and the positioning platform (321) contacts two adjacent positioning blocks (5).

5. The automatic injection pen according to claim 4, characterized in that: The bracket (3) further comprises a first reinforcing rib portion (34), the first reinforcing rib portion (34) being located on a side of the positioning platform (321) away from the first positioning portion (31), and the first reinforcing rib portion (34) connecting the bracket (3) and the positioning platform (321).

6. The automatic injection pen according to claim 1, characterized in that: The bracket (3) further comprises a mounting portion (35), wherein a plurality of mounting portions (35) are arranged circumferentially, and the mounting portions (35) are in contact with the inner wall of the housing (1).

7. The automatic injection pen according to claim 6, characterized in that: The bracket (3) further comprises a second reinforcing rib portion (36), wherein the second reinforcing rib portion (36) connects the mounting portion (35) and the bracket (3).

8. The automatic injection pen according to claim 1, characterized in that: The automatic injection pen further comprises a protective sleeve (6) and an elastic member (7), wherein the protective sleeve (6) is movably connected to an end of the bracket (3) close to the opening (101), and the protective sleeve (6) partially extends outside the opening (101), and the needle of the syringe (4) extends into the protective sleeve (6), and the elastic member (7) connects the protective sleeve (6) and the bracket (3) to fix the protective sleeve (6); When the protective sleeve (6) is subjected to force, the protective sleeve (6) can retract away from the opening (101).

9. The automatic injection pen according to claim 8, characterized in that: A second clamping block (11) is provided on the inner wall of the shell (1), and the second clamping block (11) is located at one end of the shell (1) close to the opening (101); The outer wall of the protective sleeve (6) is further provided with a strip-shaped card slot (601), the length direction of the card slot (601) is parallel to the axial direction of the syringe (4), and in the axial direction of the syringe (4), the length of the card slot (601) is greater than the length of the second card block (11); Wherein, when the bracket (3) is located at the first position, the second clamping block (11) is located between the clamping slot (601) and the opening (101), and the clamping slot (601) and the second clamping block (11) are arranged along the axial direction of the syringe (4), and the second clamping block (11) is used to clamp on one end of the clamping slot (601) close to the opening (101) to prevent the protective sleeve (6) from retracting back to the opening (101).

10. The automatic injection pen according to claim 1, characterized in that: The automatic injection pen further comprises a protective cap (8), wherein the protective cap (8) is detachably connected to the housing (1) and covers the opening (101).

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