Sound production mechanism of pre-filled-and-sealed automatic injection pen, and pre-filled-and-sealed automatic injection pen

Abstract

Provided are a sound production mechanism of a pre-filled-and-sealed automatic injection pen, and a pre-filled-and-sealed automatic injection pen. The sound production mechanism of the pre-filled-and-sealed automatic injection pen comprises: a supporting frame (1), which is fixed in a shell (10) of a pre-filled-and-sealed automatic injection pen and is configured to limit the initial positions of a push rod (6) and a sound production member (3) at the beginning; the sound production member (3), which is mounted in the supporting frame (1), is positioned by the supporting frame (1) at the beginning, and can impact on the supporting frame (1) to produce a sound when the injection is finished; the push rod (6), which is mounted in the supporting frame (1), is positioned by the supporting frame (1) at the beginning, can be triggered and drive a pre-filled-and-sealed syringe (8) to move to complete automatic needle feeding, and drives, after same reaches a limit position, the sound production member (3) to disengage from the initial position thereof; and a rear cover (2), which is fixed to the rear end of the supporting frame (1) and fits onto the supporting frame (1) to initially position the sound production member (3). The consistently stationary supporting frame (1) fits onto the rear cover (2) to support the sound production member (3), such that it is ensured that the sound production member (3) can be stably supported during the action process of the push rod (6), and is triggered, when the push rod (6) reaches the limit position, to produce a sound, thereby ensuring the reliability of reminding of the completion of injection.

Description

Sounding mechanism of prefilled automatic injection pen and prefilled automatic injection pen Technical Field

[0001] The present invention belongs to the technical field of automatic injection, and in particular relates to a sounding mechanism of a prefilled automatic injection pen and the prefilled automatic injection pen. Background Art

[0002] An autoinjector is a medical device that automatically injects liquid medication from a prefilled syringe into a patient's body, meeting the user's need for self-administration. Since most patients are not professional medical professionals, autoinjectors are typically required to be simple to use, highly reliable, and comfortable, and to emit a prompt signal after the injection is completed to help the user confirm the injection is complete.

[0003] Existing autoinjectors typically require the front end of the syringe to be pressed against the area where injection is desired, while the back end of the syringe is manually moved. Once the front end of the autoinjector is positioned at the patient's injection site, a triggering element is pressed to activate the autoinjector, allowing the needle to quickly puncture the skin and automatically inject the medication.

[0004] Existing CN112076364A discloses an automatic injector comprising a rattle, which is the primary component that emits a prompt signal after the push rod completes injection. The rattle is axially slidably sleeved around the outer periphery of the push rod. A driving elastic member acts on the rattle, driving it to slide toward the rear end of the housing. This allows the rattle to provide a signal under the elastic force of the driving elastic member. The driving elastic member and the rattle are constrained by other components to maintain their initial assembly state, preventing them from sliding toward the rear end of the housing. The rattle is provided with a push rod retaining mechanism. A rattle retaining mechanism is provided between the rattle and the inner tube, maintaining their relative position in a fixed position during the initial assembly state. Once the rattle is freed from the axial restraint of the inner tube, it moves toward the rear end of the housing under the elastic force of the push rod, simultaneously emitting a prompt signal. This sounding mechanism employs dynamic support between the push rod and the rattle, which can be unstable, resulting in premature sounding before the injection is complete. Summary of the Invention

[0005] In view of the problems existing in the above background technology, the purpose of the present invention is to provide a sounding mechanism of a prefilled automatic injection pen and a prefilled automatic injection pen with a reliable injection completion reminder function.

[0006] The technical solution adopted in the present invention is:

[0007] A sounding mechanism of a pre-filled automatic injection pen, comprising

[0008] A support frame, which is fixed in the housing of the pre-filled automatic injection pen and is used to initially define the initial positions of the push rod and the sounding member;

[0009] A sound-generating member, which is installed in the support frame and is initially positioned by the support frame, and can strike the support frame to generate a sound at the end of the injection;

[0010] The push rod is installed in the support frame and is initially positioned by the support frame. It can be triggered to drive the pre-filled syringe to move and complete automatic needle insertion. After reaching the limit position, it drives the sounding part out of the initial position;

[0011] The rear cover is fixed to the rear end of the support frame and cooperates with the support frame to initially position the sound-generating component.

[0012] Furthermore, a sounding spring is installed between the rear end of the sounding member and the rear cover to drive the sounding member to hit the support frame.

[0013] Furthermore, a receiving cavity for receiving a sound-generating spring is provided in the rear cover.

[0014] Furthermore, a positioning rod is provided in the support frame, the push rod is sleeved outside the positioning rod and an excitation spring capable of driving the push rod is provided between the push rod and the positioning rod.

[0015] Furthermore, when the sounding member is in the initial position, a distance is provided between its rear end and the rear end of the positioning rod, and the rear end of the sounding member can hit the rear end of the positioning rod to produce sound when the injection is completed.

[0016] Furthermore, the sound-generating component includes a U-shaped sound-generating body, and both front ends of the U-shaped sound-generating body are provided with cantilevers.

[0017] Furthermore, a step surface is provided inside the front end of the support frame for initially limiting the position of the cantilever.

[0018] Furthermore, the rear end of the push rod is provided with a convex portion for pushing the cantilever out of the step surface.

[0019] A prefilled automatic injection pen comprising

[0020] a housing, which is a hollow structure;

[0021] The pen cap is snapped onto the head of the housing and can cause the inner protective rubber cover of the prefilled syringe to fall off together with it when it is pulled off;

[0022] The excitation sleeve is movably mounted in the housing and is provided with a return spring for resetting along the axial direction between the housing and the excitation sleeve. The head of the excitation sleeve is exposed outside the housing and can touch the protective sleeve when it moves from the initial position to the limit position.

[0023] The prefilled syringe is clamped on the fixed seat when pre-filled. When the activation sleeve moves from the initial position to the extreme position, the injection end of the prefilled syringe is always hidden in the needle sheath. When the injection end of the prefilled syringe is triggered, it moves instantly, extending the activation sleeve to realize automatic needle insertion.

[0024] A fixing seat is fixedly installed between the ignition sleeve and the prefilled syringe, and initially defines the initial position of the prefilled syringe and provides support when the prefilled syringe is automatically inserted into the needle;

[0025] The protective sleeve is installed outside the support frame. Initially, it is buckled outside the support frame and can be moved by the excitation sleeve to trigger the push rod. At the same time, it can limit the excitation sleeve from moving backward to protect the needle after moving;

[0026] The sound-generating mechanism is installed in the shell.

[0027] Compared with the existing technology, the present invention has the following significant advantages: the sound-emitting part is supported by the support frame that is always stationary and cooperates with the back cover to ensure that the sound-emitting part can be stably supported during the movement of the push rod, and the sound is triggered only when the push rod reaches the limit position, thereby ensuring the reliability of the injection completion reminder. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] FIG1 is a schematic cross-sectional view of the sound-generating mechanism of the present invention;

[0029] FIG2 is a schematic diagram of the operation flow of the sound-generating mechanism of the present invention;

[0030] FIG3 is a schematic cross-sectional view of the support frame and the back cover after assembly according to the present invention.

[0031] FIG4 is a schematic structural diagram of the sound-generating member of the present invention.

[0032] FIG5 is a schematic diagram of the explosion structure of the prefilled automatic injection pen of the present invention.

[0033] Among them, 1. support frame, 11. positioning part, 12. step surface; 2. back cover, 21. accommodating chamber, 3. sounding part, 31. U-shaped sounding body, 32. cantilever, 4. sounding spring, 5. excitation spring, 6. push rod, 61. convex part, 7. protective cover, 8. prefilled syringe, 9. fixing seat, 10. shell, 20. excitation sleeve, 30. return spring. DETAILED DESCRIPTION

[0034] The present invention will be further described below with reference to specific embodiments, but the present invention is not limited to these specific embodiments. Those skilled in the art should recognize that the present invention covers all possible alternatives, improvements and equivalents within the scope of the claims.

[0035] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more, unless otherwise clearly defined.

[0036] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0037] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0038] 1-4, this embodiment provides a sound-generating mechanism for a pre-filled automatic injection pen, comprising

[0039] The support frame 1 is fixed in the housing of the pre-filled automatic injection pen and is used to initially define the initial positions of the push rod 6 and the sounding member 3;

[0040] The sound-generating member 3 is installed in the support frame 1 and is initially positioned by the support frame 1, and can strike the support frame 1 to produce a sound at the end of the injection;

[0041] The push rod 6 is installed in the support frame 1 and is initially positioned by the support frame 1. It can be triggered to drive the pre-filled syringe to move and complete automatic needle insertion. After reaching the limit position, it drives the sounding member 3 out of the initial position;

[0042] The rear cover 2 is fixed to the rear end of the support frame 1 and cooperates with the support frame 1 to initially position the sound-emitting member 3 .

[0043] In this embodiment, a sound spring 4 is installed between the rear end of the sound member 3 and the rear cover 2 to drive the sound member 3 to hit the support frame 1. The rear cover 2 is provided with an accommodating cavity 21 for accommodating the sound spring 4.

[0044] In this embodiment, the support frame 1 is provided with a positioning rod 11, and the push rod 6 is sleeved outside the positioning rod 11. An excitation spring 5 is provided between the push rod 6 and the positioning rod 11 to drive the push rod 6. When the sounding member 3 is in the initial position, there is a gap between its rear end and the rear end of the positioning rod 11. The rear end of the sounding member 3 can strike the rear end of the positioning rod 11 to produce a sound when the injection is completed.

[0045] The sounding member 3 of this embodiment comprises a U-shaped sounding body 31, each of which is provided with cantilevers 32 at its front end. The front end of the support frame 1 is internally provided with a stepped surface 12 that initially engages with the cantilevers 32. The rear end of the push rod 6 is provided with a protrusion 61 that pushes the cantilevers 32 off the stepped surface 12.

[0046] The sounding part 3 of the present invention is fixed to the step surface 12 on the support frame 1 through the cantilever 32, and the rear sounding spring 4 is compressed to store force. When the push rod 6 is excited, the excitation spring 5 inside the push rod is in a stored force state, and the push rod 6 releases the excitation. When the push rod 6 reaches the limit position, its protrusion 61 pushes the cantilever 32 away, causing the cantilever 32 to slide out from the step surface 12 on the support frame 1, and hits the rear end of the positioning rod 11 under the elastic force of the sounding spring 4 to issue a prompt signal sound, and the sound is stable and reliable.

[0047] The present invention supports the sounding member 3 by cooperating with the support frame 1 and the back cover 2, thereby ensuring that the sounding member 3 can be stably supported during the movement of the push rod 6, and is not triggered to sound until the push rod 6 reaches the limit position, thereby ensuring the reliability of the injection completion reminder.

[0048] Example 2

[0049] Referring to FIG5 , this embodiment provides a pre-filled automatic injection pen, comprising

[0050] The housing 10 is a hollow structure;

[0051] The pen cap is snapped onto the head of the housing and can cause the inner protective rubber cover of the prefilled syringe to fall off together with it when it is pulled off;

[0052] The excitation sleeve 20 is movably mounted in the housing 10 and is provided with a return spring 30 for resetting along the axial direction between the housing 10. The head of the excitation sleeve 20 is exposed outside the housing 10. When the excitation sleeve 20 moves from the initial position to the limit position, it can touch the protective sleeve 7.

[0053] The prefilled syringe 8 is clamped on the fixing seat 9 when pre-installed. During the movement of the trigger sleeve 20 from the initial position to the extreme position, the injection end of the prefilled syringe 8 is always hidden in the needle sheath. When the injection end of the prefilled syringe 8 is triggered, it moves instantly and extends the trigger sleeve 20 to realize automatic needle insertion.

[0054] The fixing seat 9 is fixedly installed between the ignition sleeve 20 and the prefilled syringe 8, and initially defines the initial position of the prefilled syringe 8 and can provide support when the prefilled syringe 8 is automatically inserted into the needle;

[0055] The protective sleeve 7 is mounted on the outside of the support frame 1. Initially, it is fastened to the outside of the support frame 1 and can be moved by the excitation sleeve 20 to trigger the push rod 6. At the same time, after the movement, it can limit the excitation sleeve 20 from moving backward to protect the needle;

[0056] The sound-generating mechanism described in the first embodiment is installed in the housing 10 .

[0057] The pen cap of this embodiment snaps onto the top of the housing 10 and, when removed, removes the inner protective rubber sheath of the prefilled syringe 8. Specifically, the pen cap is provided with symmetrically arranged cap clips that initially engage the inner protective rubber sheath of the prefilled syringe. When the pen cap is removed, the inner protective rubber sheath of the prefilled syringe 8 separates from the prefilled syringe 8, exposing the needle.

[0058] The housing 10 of this embodiment is a hollow structure. The housing 10 is provided with a visual window for checking the status of the drug solution, whether the pre-filled syringe is positioned correctly, and for checking the infusion status after registration is completed.

[0059] The excitation sleeve 20 described in this embodiment is movably installed in the housing 10 and is axially provided with a return spring 30 for resetting between the housing 10. The head of the excitation sleeve 20 is exposed outside the housing 10. When it moves from the initial position to the extreme position, it can trigger the excitation component. Specifically, the excitation sleeve 20 includes an excitation sleeve body that protects the needle tip. The tail end of the excitation sleeve body is extended with a symmetrically arranged excitation portion. The excitation portion is provided with a slot for the second cantilever of the fixed seat to move. The inner side of the excitation portion is provided with a protective buckle at one end of the slot that radially protrudes to limit the initial position of the second cantilever of the fixed seat 9. After the rear end of the excitation portion moves, it contacts the linkage portion of the protective sleeve 7, thereby driving the protective sleeve 7 to move backward to achieve excitation of the excitation component.

[0060] The prefilled syringe 8 described in this embodiment is clamped on the fixing seat 9 when pre-installed. During the process of the activation sleeve 20 moving from the initial position to the extreme position, the injection end of the prefilled syringe 8 is always hidden in the needle sheath. When the injection end of the prefilled syringe 8 is triggered, it is displaced instantly and the activation sleeve 20 is extended to realize automatic needle insertion. Specifically, the prefilled syringe 8 is clamped at the position of the second cantilever on the fixed seat 9 when pre-installed. This position is the initial position of the prefilled syringe 8. When excited, the excitation sleeve 20 moves from the initial position to the extreme position. When the excitation sleeve 20 is at the extreme position, the injection end of the prefilled syringe 8 is hidden in the excitation sleeve 20. When the injection end of the prefilled syringe 8 is triggered, it is displaced instantly, moving from the initial position to the stepped surface on the fixed seat 9, and exceeding the excitation sleeve 20 to realize automatic needle insertion; the injection end is a needle structure, and an internal protective rubber sleeve is initially provided to protect the injection end; the prefilled syringe 8 is pre-filled with liquid and sealed by a rubber plug; the protruding tail end of the prefilled syringe 8 is protruding, which can be limited to the initial position by the fixed seat 9, and cooperate with the stepped surface on the fixed seat 9 to limit the moving distance.

[0061] The fixing seat 9 described in this embodiment is fixedly installed between the activation sleeve 20 and the prefilled syringe 8, and initially defines the initial position of the prefilled syringe 8 and can provide support when the prefilled syringe 8 is automatically inserted into the needle. The fixing seat 9 is symmetrically provided with a second cantilever, and the second cantilever is provided corresponding to the slot of the activation sleeve 20. The outer side of the end of the second cantilever is provided with an outer buckle that initially cooperates with the protective buckle of the activation sleeve 20 to define the position of the second cantilever, and the inner side of the end of the second cantilever is provided with an inner buckle that initially cooperates with the protruding tail end of the prefilled syringe 8 to support the prefilled syringe 8. The inner wall of the fixing seat 9 is provided with a stepped surface that limits the movement of the prefilled syringe 8. The inner wall of the fixing seat 9 is axially provided with vertical ribs from the stepped surface to its tail end to provide support for the prefilled syringe 8 when the needle is automatically inserted into the needle. After the outer buckle of the second cantilever of the fixing seat 9 is separated from the protective buckle, the second cantilever can be deformed in the slot, so that the prefilled syringe 8 is pushed open by the push rod 6 and moves down to the stepped surface. A silicone gasket may be provided on the stepped surface to protect the protruding tail end of the prefilled syringe 8 and prevent it from breaking during movement.

[0062] The support frame 1 of this embodiment is fixed within the housing 10 and serves to initially define the initial positions of the push rod 6, the sounding member 3, and the protective sleeve 7. Specifically, a positioning rod 11 is disposed within the support frame 1. The push rod 6 is sleeved outside the positioning rod 11, with an excitation spring 5 disposed between the positioning rod 11 to drive the push rod 6. When the sounding member 3 is in its initial position, a gap is provided between its rear end and the rear end of the positioning rod 11. The rear end of the sounding member 3 can strike the rear end of the positioning rod 11 to produce a sound at the end of an injection. The support frame 1 is provided with a first positioning groove for initially cooperating with the protective cover 7 for positioning, and the support frame 1 is provided with a limiting portion on the rear side of the first positioning groove for cooperating with the protective cover 7 for positioning after movement. The support frame 1 is provided with a first cantilever, and the inner wall of the first cantilever is provided with a first positioning buckle for initially cooperating with the push rod 6 for positioning. The first cantilever is initially pressed by the protective cover 7 so that the first positioning buckle is buckled on the push rod 6. The rear end of the support frame 1 is provided with a second positioning groove for fixing the back cover 2, and the outer surface of the support frame 1 is symmetrically provided with arc-shaped protrusions for propping up the protective cover 7 to resist the excitation cover 20.

[0063] The push rod 6 described in this embodiment is installed in the support frame 1 and is initially positioned by the support frame 1. After the protective cover 7 is triggered, it drives the prefilled syringe 8 to move under the drive of the excitation spring 6 to complete automatic needle insertion. Specifically, the push rod 6 is provided with a third positioning groove that cooperates with the first positioning buckle for initial positioning. The head of the push rod 6 is the pushing end that contacts the plug of the prefilled syringe 8, and the interior of the push rod 6 is a hollow structure that accommodates the excitation spring 6.

[0064] The protective cover 7 of this embodiment is mounted on the outside of the support frame 1. Initially, it is engaged with the outside of the support frame 1 and can be moved by the activation cover 20 to trigger the push rod 6. Furthermore, after the movement, the activation cover 20 can be restricted from moving backward to protect the needle. Specifically, the front wall of the protective cover 7 is provided with a notch, thereby forming a deformable structure at the front end. The deformable front end is symmetrically arranged, and the deformable front end can be stretched open under the action of the support frame 1 to resist the rear end of the excitation sleeve 20. A linkage part is protruded on the outer surface of the deformable front end, and the linkage part is driven by the rear end of the excitation sleeve 20 to drive the protective sleeve 7 to move backward. A second positioning buckle is provided on the inner side of the rear end of the protective sleeve 7, and the second positioning buckle can be buckled on the support frame 1 at the beginning and after movement. The protective sleeve 7 is provided with a first sliding groove which initially accommodates the protrusion and provides a stretching space for the first cantilever after movement. The setting of the first sliding groove makes the protective sleeve 7 not deformed at the beginning and in the front part of the backward movement process. Only when the deformable front end moves to the protrusion, it is stretched and deformed, thereby limiting the backward movement of the excitation sleeve 20, and when the first sliding groove moves to the first cantilever position, the first cantilever can be stretched open by the push rod 6 so that the push rod 6 leaves the initial position and moves under the action of the excitation spring 6.

[0065] The sounding member 3 of this embodiment comprises a U-shaped sounding body 31, each of which is provided with cantilevers 32 at its front end. The front end of the support frame 1 is internally provided with a stepped surface 12 that initially engages with the cantilevers 32. The rear end of the push rod 6 is provided with a protrusion 61 that pushes the cantilevers 32 off the stepped surface 12.

[0066] The rear cover 12 described in this embodiment is fixed to the rear end of the support frame 1 and cooperates with the support frame 1 to initially position the sound-emitting member 3 .

[0067] The sounding part 3 of the present invention is fixed to the step surface 12 on the support frame 1 through the cantilever 32, and the rear sounding spring 4 is compressed to store force. When the push rod 6 is excited, the excitation spring 5 inside the push rod is in a stored force state, and the push rod 6 releases the excitation. When the push rod 6 reaches the limit position, its protrusion 61 pushes the cantilever 32 away, causing the cantilever 32 to slide out from the step surface 12 on the support frame 1, and hits the rear end of the positioning rod 11 under the elastic force of the sounding spring 4 to issue a prompt signal sound, and the sound is stable and reliable.

[0068] The present invention supports the sounding member 3 by cooperating with the support frame 1 and the back cover 2, thereby ensuring that the sounding member 3 can be stably supported during the movement of the push rod 6, and is not triggered to sound until the push rod 6 reaches the limit position, thereby ensuring the reliability of the injection completion reminder.

Claims

1. A sound-generating mechanism for a prefilled automatic injection pen, characterized in that: include A support frame (1) is fixed in the housing (10) of the prefilled automatic injection pen and is used to initially define the initial positions of the push rod (6) and the sounding member (3); A sound-generating member (3) is installed in the support frame (1) and is initially positioned by the support frame (1), and can strike the support frame (1) to generate a sound when the injection is completed; A push rod (6) is installed in the support frame (1) and is initially positioned by the support frame (1). It can be triggered to drive the pre-filled syringe (8) to move and automatically insert the needle. After reaching the limit position, it drives the sounding member (3) to leave the initial position. The rear cover (2) is fixed to the rear end of the support frame (1) and cooperates with the support frame (1) to initially position the sound-generating member (3).

2. The sound-generating mechanism of a prefilled automatic injection pen according to claim 1, characterized in that: A sound-generating spring (4) is installed between the rear end of the sound-generating member (3) and the rear cover (2) to drive the sound-generating member (3) to collide with the support frame (1).

3. The sound-generating mechanism of a prefilled automatic injection pen according to claim 2, characterized in that: The rear cover (2) is provided with a receiving cavity (21) for receiving a sound-generating spring (4).

4. The sound-generating mechanism of a prefilled automatic injection pen according to claim 1, characterized in that: A positioning rod (11) is arranged inside the support frame (1), the push rod (6) is sleeved outside the positioning rod (11), and an excitation spring (5) capable of driving the push rod (6) is arranged between the push rod and the positioning rod (11).

5. The sound-generating mechanism of a prefilled automatic injection pen according to claim 4, characterized in that: When the sound-generating member (3) is in the initial position, a distance is provided between its rear end and the rear end of the positioning rod (11). The rear end of the sound-generating member (3) can collide with the rear end of the positioning rod (11) to generate sound when the injection is completed.

6. The sound-generating mechanism of a prefilled automatic injection pen according to claim 1, characterized in that: The sound-generating member (3) comprises a U-shaped sound-generating body (31), and both front ends of the U-shaped sound-generating body (31) are provided with cantilevers (32).

7. The sound-generating mechanism of a prefilled automatic injection pen according to claim 6, characterized in that: A step surface (12) is provided inside the front end of the support frame (1) for initially limiting the position of the cantilever (32).

8. The sound-generating mechanism of a prefilled automatic injection pen according to claim 7, characterized in that: The rear end of the push rod (6) is provided with a convex portion (61) for pushing the cantilever (32) out of the step surface.

9. A prefilled automatic injection pen comprising A housing (10) which is a hollow structure; A pen cap, which is buckled on the head of the housing (10) and can drive the inner protective rubber sleeve of the prefilled syringe (8) to fall off together when it is pulled off; An excitation sleeve (20) is movably mounted in the housing (10) and is provided with a return spring (30) for resetting along the axial direction between the housing (10). The head of the excitation sleeve (20) is exposed outside the housing and can touch the protective sleeve (7) when it moves from an initial position to an extreme position. The prefilled syringe (8) is clamped on a fixing seat (9) when pre-installed. When the activation sleeve (20) moves from an initial position to an extreme position, the injection end of the prefilled syringe (8) is always hidden in the needle sheath. When the injection end of the prefilled syringe (8) is triggered, it is instantly displaced and extends out of the activation sleeve (20) to achieve automatic needle insertion. A fixing seat (9) is fixedly installed between the ignition sleeve (20) and the prefilled syringe (8), and initially defines the initial position of the prefilled syringe (8) and can provide support when the prefilled syringe (8) is automatically inserted; A protective sleeve (7) is mounted outside the support frame (1), is initially buckled outside the support frame (1), and can be driven by the excitation sleeve (20) to move and trigger the push rod (6), and can also limit the excitation sleeve (20) from moving backwards to protect the needle after moving; Features: The housing (10) has a sound-generating mechanism as claimed in any one of claims 1 to 9 installed in it.

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