An automatic injection pen

Abstract

The utility model discloses an automatic injection pen, including the pen tube shell of open front end, be equipped with pre-filled sealed syringe in the pen tube shell, be equipped with the medicine pushing rod and locking mechanism in the pen tube shell, the pen tube shell still has the unlocking structure of sliding connection, the pen tube shell still is equipped with when the first elastic element of the first prompt sound and makes pre-filled sealed syringe to inject of the piston of pre-filled sealed syringe is hit in the medicine pushing rod after the unlocking of locking mechanism and pushes, be equipped with when the medicine pushing rod is in initial state and is locked, when the medicine pushing rod advances second preset distance and makes pre-filled sealed syringe to inject when being unlocked and thus hit on the pen tube shell and send the second prompt sound of prompting piece of the pen tube shell. The product can produce clear discernible sound at injection start and injection complete two key nodes respectively, so that the user can accurately judge injection process without relying on vision, is applicable to the operation of visually impaired population or emergency scene, improves the security of taking medicine and the psychological security.

Description

Technical Field

[0001] This utility model relates to the field of medical and health care device technology, and in particular to an automatic injection pen. Background Technology

[0002] With the rapid development of biopharmaceutical technology, an increasing number of therapeutic drugs require administration via subcutaneous or intramuscular injection. Traditional injection methods rely on medical personnel, which not only places a psychological burden on patients but also limits the self-management abilities of patients with chronic diseases. To improve medication adherence and safety, automated injection pens, as portable and easy-to-use drug delivery devices, have been widely used in home and out-of-hospital settings.

[0003] Existing automated injection pens typically consist of a housing, a built-in pre-filled syringe, a drive mechanism, and a safety protection structure. Their basic working principle is that when the user triggers the device, an internal elastic element releases energy, pushing the syringe piston to inject the medication. However, existing products still have many shortcomings in terms of safety, operational feedback, and user experience.

[0004] First, regarding injection process prompts, users find it difficult to intuitively determine whether the injection has started or finished. Although some products introduce sound or visual cues, these largely rely on electronic components, increasing structural complexity and cost, and limiting reliability. Second, after injection, the drug delivery mechanism often remains at the endpoint, lacking clear "injection complete" feedback, which affects the user's confirmation of treatment completion.

[0005] This utility model is based on the above-mentioned circumstances. Utility Model Content

[0006] This invention overcomes the shortcomings of the prior art and provides an automatic injection pen that can clearly indicate the start and end of injection with two distinct sounds, thereby improving patient confidence and compliance.

[0007] This utility model is achieved through the following technical solution:

[0008] An automatic injection pen includes a pen casing with an open front end. A pre-filled syringe extends from the front end of the pen casing. The pen casing also includes a push rod that pushes the piston of the pre-filled syringe to inject medication, and a locking mechanism that locks the push rod. The pen casing is slidably connected to an unlocking structure that triggers the locking mechanism to unlock when the push rod extends from the pen casing and slides inward a first preset distance. The pen casing also includes a first elastic element that, when the locking mechanism is unlocked, pushes the push rod to strike the piston of the pre-filled syringe, emitting a first alert sound and initiating injection. A prompting element is provided between the push rod and the pen casing, which is locked when the push rod is in its initial state and unlocked when the push rod advances a second preset distance and completes injection in the pre-filled syringe, striking the pen casing and emitting a second alert sound.

[0009] As described above, in an automatic injection pen, the locking mechanism includes a fixed bracket, a push rod slidably connected to the fixed bracket, a first slot on the outer wall of the push rod, a first buckle on the fixed bracket that can engage with the first slot, and a first inclined surface on the rear side wall of the first buckle and / or the rear side wall of the first slot that allows the first buckle to disengage from the first slot when the push rod is subjected to force and moves forward. The locking mechanism also includes a sliding sleeve fitted on the outside of the fixed bracket to restrict the first buckle from disengaging from the first slot.

[0010] As described above, in an automatic injection pen, the unlocking structure includes a pusher frame that is slidably connected to the pen housing and can push a sliding sleeve when sliding into the pen housing. A second elastic element is provided between the sliding sleeve and the pen housing to push the sliding sleeve to reset.

[0011] As described above, in an automatic injection pen, the indicator is sleeved on the rear end of the push rod. The front end of the indicator has a second buckle that can engage with a fixed bracket. The rear side wall of the second buckle has a second inclined surface for engaging with the fixed bracket to release the buckle. The first elastic element is disposed between the push rod and the indicator. When the push rod advances but has not reached a second preset distance, the push rod restricts the second buckle from releasing. When the push rod advances to the second preset distance, the push rod leaves the second buckle, causing the second buckle to release its restriction. When the first elastic element pushes the indicator backward, it pushes the second buckle to release, and the indicator strikes the pen cartridge shell, emitting a second indicator sound.

[0012] As described above, in an automatic injection pen, the sliding sleeve is provided with a third latch that, when the indicator strikes the pen barrel shell, elastically resets and abuts against the front end of the indicator, thereby limiting the reset of the indicator.

[0013] As described above, in an automatic injection pen, the outer wall of the indicator is provided with a second slot for a third buckle to engage, and the front and rear walls of the second slot are provided with a third inclined surface to facilitate the disengagement of the third buckle.

[0014] As described above, in an automatic injection pen, the outer wall of the indicator is provided with a groove that communicates with the second slot for the third buckle to slide back and forth.

[0015] As described above, in an automatic injection pen, the front end of the pen barrel is detachably connected to a cap for fitting over the outside of the front end of the unlocking mechanism to prevent accidental activation.

[0016] As described above, in an automatic injection pen, the front end of the pre-filled syringe is detachably connected to a needle cap, and the cap is provided with a fourth latch that pulls the needle cap out together when it is pulled out of the pen cartridge.

[0017] As described above, an automatic injection pen has an observation window on its barrel for observing a pre-filled syringe, and a retainer on the inner edge of the observation window that cooperates with a fixed bracket to restrict the movement of the pre-filled syringe.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] This product produces clear and distinct sounds at the two key stages of injection initiation and completion, allowing users to accurately judge the injection progress without relying on vision. It is especially suitable for visually impaired individuals or in emergency situations, significantly improving medication safety and psychological reassurance.

[0020] The entire triggering, injection, and alerting process is achieved through mechanical components, eliminating the need for electronic control modules or power supplies. It features a simple structure, high stability, and strong environmental adaptability, making it suitable for various temperature, humidity, and electromagnetic environments. It also helps reduce manufacturing costs and maintenance complexity.

[0021] When the pusher advances to the second preset distance, corresponding to the position where the medication is completely dispensed, the indicator unlocks from the pusher and strikes the pen holder housing to emit a second warning sound, clearly informing the user that the injection is complete. This mechanism effectively prevents users from prematurely removing the device due to uncertainty about whether the injection is finished, ensuring accurate and complete dosage. Attached Figure Description

[0022] The specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings, wherein:

[0023] Figure 1 This is an exploded view of the present invention;

[0024] Figure 2 This is a cross-sectional view of the present invention before injection. Figure 1 ;

[0025] Figure 3 This is a cross-sectional view of the present invention before injection. Figure 2 ;

[0026] Figure 4 This is a cross-sectional view of the present invention after injection. Figure 1 ;

[0027] Figure 5 This is a cross-sectional view of the present invention after injection. Figure 2 ;

[0028] Figure 6 This is a cross-sectional view of the self-locking needle retraction mechanism of this utility model. Figure 1 ;

[0029] Figure 7 This is a cross-sectional view of the self-locking needle retraction mechanism of this utility model. Figure 2 ;

[0030] Figure 8 This is a schematic diagram of the locking structure of this utility model;

[0031] Figure 9 This is an exploded view of the locking structure of this utility model;

[0032] Figure 10 This is a cross-sectional schematic diagram of the front pen holder of this utility model. Detailed Implementation

[0033] The present invention will be further described below with reference to the accompanying drawings:

[0034] like Figures 1 to 10 An automatic injection pen is shown, comprising a pen housing 1 with an open front end, a pre-filled syringe 2 extending from its front end inside the pen housing 1, a push rod 4 for injecting medication by pushing the piston of the pre-filled syringe 2 inside the pen housing 1, and a locking mechanism for locking the push rod 4. An unlocking structure 6 is slidably connected to the pen housing 1, which triggers the unlocking mechanism when the front end extends from the pen housing 1 and slides inward a first preset distance. The pen housing 1 also has a first elastic element 71 that, when the locking mechanism is unlocked, pushes the push rod 4 to strike the piston of the pre-filled syringe 2, thereby emitting a first prompt sound and initiating injection by the pre-filled syringe 2. A prompting element 8 is provided between the push rod 4 and the pen housing 1, which is locked when the push rod 4 is in its initial state and unlocked when the push rod 4 advances a second preset distance and completes injection by striking the pen housing 1, thereby emitting a second prompt sound.

[0035] This product uses a purely mechanical structure to generate clear and distinct sounds at the two key points of injection initiation and completion, allowing users to accurately judge the injection progress without relying on vision. It is especially suitable for visually impaired individuals or emergency situations, significantly improving medication safety and psychological reassurance. The entire triggering, injection, and prompting process requires no electronic control module or power supply, featuring a simple structure, high stability, and strong environmental adaptability. It can reliably operate in various temperature, humidity, and electromagnetic environments, while also helping to reduce manufacturing costs and maintenance complexity. When the push rod 4 advances to the second preset distance, i.e., the position where the medication is completely discharged, the prompting element 8 unlocks from the push rod 4 and strikes the pen holder housing 1, emitting a second prompt sound, clearly informing the user that the injection is complete. This effectively prevents premature removal of the device due to uncertainty about whether the injection is finished, ensuring accurate and complete dosage.

[0036] In one embodiment, the pen holder 1 includes a front shell and a rear shell, the pre-filled syringe 2 is disposed in the front shell, the push rod 4, the locking structure and the indicator 8 are disposed in the rear shell, the unlocking structure 6 is disposed between the front shell and the rear shell, and the front shell and the rear shell are connected by a snap-fit, or of course, they can also be connected by other connection methods such as threads.

[0037] Furthermore, the locking mechanism includes a fixed bracket 51, the push rod 4 is slidably connected to the fixed bracket 51, the outer wall of the push rod 4 is provided with a first slot 41, the fixed bracket 51 is provided with a first buckle 511 that can engage with the first slot 41, the rear side wall of the first buckle 511 and / or the rear side wall of the first slot 41 are provided with a first inclined surface 411 that allows the first buckle 511 to disengage from the first slot 41 when the push rod 4 moves forward under force, the locking mechanism also includes a sliding sleeve 9 sleeved on the outside of the fixed bracket 51 to restrict the first buckle 511 from disengaging from the first slot 41. The fixed bracket 51 is fixed to the pen barrel shell 1 by the cooperation of the locking block and the slot, or it can be fixed to the pen barrel shell 1 by threaded connection or other connection methods, the fixed bracket 51 is provided with an elastic arm 512 for pressing the pre-filled syringe 2.

[0038] The locking mechanism employs a "buckle-slot" mechanical engagement for primary locking, while the sliding sleeve 9 applies radial constraint to the first buckle 511, forming a secondary limit. Even under extreme conditions such as transport vibration or accidental drops, the force exerted on the push rod 4 alone is insufficient to disengage the buckle; the constraint of the sliding sleeve 9 must be released first before the push rod 4 can be released. This dual locking mechanism greatly improves the safety of the device and effectively prevents unintended injections.

[0039] Furthermore, the unlocking structure 6 includes a pusher frame that is slidably connected to the pen holder shell 1 and can push the sliding sleeve 9 when sliding into the pen holder shell 1. A second elastic element 72 that can push the sliding sleeve 9 to reset is provided between the sliding sleeve 9 and the pen holder shell 1. Both the first elastic element 71 and the second elastic element 72 can be reset springs.

[0040] Furthermore, the prompting element 8 is sleeved on the rear end of the push rod 4. The front end of the prompting element 8 is provided with a second buckle 81 that can engage with the fixed bracket 51. The rear side wall of the second buckle 81 is provided with a second inclined surface 811 for engaging with the fixed bracket 51 to release the buckle. The first elastic element 71 is provided between the push rod 4 and the prompting element 8. When the push rod 4 advances but does not reach the second preset distance, the push rod 4 restricts the second buckle 81 from releasing. When the push rod 4 advances to the second preset distance, the push rod 4 leaves the second buckle 81, causing the second buckle 81 to release the restriction. When the first elastic element 71 pushes the prompting element 8 backward, it pushes the second buckle 81 to release. The prompting element 8 hits the pen holder shell 1 and emits a second prompting sound.

[0041] The first elastic element 71 not only drives the syringe plunger 4 to complete the injection, but also, after the injection, drives the indicator 8 to move backward to trigger the second alert sound, achieving "dual use of a single spring". This energy reuse design reduces the number of parts, optimizes the internal space layout, and ensures that both sounds are driven by the same highly consistent elastic source, improving the predictability and recognizability of the sound feedback.

[0042] Furthermore, the prompting element 8 is also provided with a positioning guide rod 100 that can be inserted into the push rod 4, thereby positioning and guiding the push rod 4 and the first elastic element 71.

[0043] In some embodiments, the sliding sleeve 9 is provided with a third latch 91 that, when the indicator 8 impacts the pen cartridge housing 1, elastically resets and abuts against the front end of the indicator 8, thereby limiting the reset of the indicator 8. In disposable auto-injection pens, preventing reuse is an important safety requirement. The limiting effect of the third latch 91 on the indicator 8 makes it difficult to restore it to its initial ready-to-use state even if forcibly disassembled or subjected to external force. Structurally, it inherently possesses anti-reuse characteristics, helping to meet the safety requirements for disposable products under medical device regulations.

[0044] Furthermore, the outer wall of the reminder element 8 is provided with a second slot 82 for the third buckle 91 to engage. The front and rear walls of the second slot 82 are provided with a third inclined surface 821 to facilitate the disengagement of the third buckle 91. The outer wall of the reminder element 8 is provided with a sliding groove 83 that communicates with the second slot 82 for the third buckle 91 to slide back and forth. This reduces the frictional resistance between the third buckle 91 and the reminder element 8, making the sliding smoother, and also guides the sliding sleeve 9.

[0045] In one embodiment, the front end of the pen holder 1 is detachably connected to a cap 3 for fitting over the outer side of the front end of the unlocking structure 6 to prevent accidental contact. The front end of the pre-filled syringe 2 is detachably connected to a needle cap 21, and the cap 3 is provided with a fourth latch 31 that pulls the needle cap 21 out together when it is pulled out of the pen holder 1.

[0046] Traditional automatic injection pens typically require users to manually remove the outer cap and then separately remove the needle cap before use. This process is cumbersome and prone to omission, leading to injection failure or needle contamination. This design mechanically links the cap 3 and needle cap 21 using a fourth latch 31. Users only need to pull out the outer cap 3 to automatically remove the needle cap 21, achieving "one pull, two removals." This significantly simplifies preparation steps and improves operational convenience, making it especially suitable for emergency situations or people with limited mobility.

[0047] In one embodiment, the pen holder shell 1 is provided with an observation window 10 for observing the pre-filled syringe 2, and the inner edge of the observation window 10 is provided with a retainer 100 that cooperates with the fixed bracket 51 to restrict the movement of the pre-filled syringe 2.

[0048] The observation window 10 allows users to directly visually inspect the state of the medication inside the pre-filled syringe 2, improving medication safety. Simultaneously, the integrated retainer 100 on its inner edge works in conjunction with the internal fixing bracket 51 to provide axial and radial restraint for the pre-filled syringe 2, effectively preventing it from shaking, shifting, or even falling off during transportation, storage, or operation. This design cleverly integrates the functional window with the structural support, avoiding the problem of reduced visibility caused by adding additional obstruction structures to strengthen fixation in traditional solutions.

Claims

1. An automatic injection pen, characterized in that: The device includes a pen holder shell (1) with an open front end. Inside the pen holder shell (1) is a pre-filled syringe (2) that extends from its front end. The pen holder shell (1) also contains a push rod (4) that pushes the piston of the pre-filled syringe (2) to inject medication, and a locking mechanism that locks the push rod (4). The pen holder shell (1) is also slidably connected to an unlocking structure (6) that triggers the locking mechanism to unlock when the front end extends from the pen holder shell (1) and slides inward a first preset distance. The pen holder shell (1) also has a mechanism that... After the locking mechanism is unlocked, the push rod (4) is pushed to strike the piston of the pre-filled syringe (2), thereby emitting the first prompt sound and causing the pre-filled syringe (2) to inject. A first elastic element (71) is provided between the push rod (4) and the pen barrel shell (1) to lock when the push rod (4) is in the initial state and to unlock when the push rod (4) advances a second preset distance and causes the pre-filled syringe (2) to finish injecting, thereby striking the pen barrel shell (1) and emitting the second prompt sound.

2. An automatic injection pen according to claim 1, characterized in that: The locking mechanism includes a fixed bracket (51), the push rod (4) is slidably connected to the fixed bracket (51), the outer wall of the push rod (4) is provided with a first slot (41), the fixed bracket (51) is provided with a first buckle (511) that can engage with the first slot (41), the rear side wall of the first buckle (511) and / or the rear side wall of the first slot (41) are provided with a first inclined surface (411) that can disengage the first buckle (511) from the first slot (41) when the push rod (4) is subjected to force and moves forward, and the locking mechanism also includes a sliding sleeve (9) sleeved on the outside of the fixed bracket (51) to restrict the first buckle (511) from disengaging from the first slot (41).

3. An automatic injection pen according to claim 2, characterized in that: The unlocking structure (6) includes a pusher that is slidably connected to the pen holder shell (1) and can push the sliding sleeve (9) when sliding into the pen holder shell (1). A second elastic element (72) is provided between the sliding sleeve (9) and the pen holder shell (1) to push the sliding sleeve (9) to reset.

4. An automatic injection pen according to claim 3, characterized in that: The prompting element (8) is sleeved on the rear end of the push rod (4). The front end of the prompting element (8) is provided with a second buckle (81) that can be engaged with the fixed bracket (51). The rear side wall of the second buckle (81) is provided with a second inclined surface (811) for engaging with the fixed bracket (51) to release the buckle. The first elastic element (71) is located between the push rod (4) and the prompting element (8). When the push rod (4) advances but does not reach the second preset distance, the push rod (4) restricts the second buckle (81) from releasing. When the push rod (4) advances to the second preset distance, the push rod (4) leaves the second buckle (81) so that the second buckle (81) is released from restriction.

5. An automatic injection pen according to claim 4, characterized in that: The sliding sleeve (9) is provided with a third buckle (91) that, when the prompting element (8) hits the pen holder shell (1), it elastically resets and abuts against the front end of the prompting element (8) to limit the reset of the prompting element (8).

6. An automatic injection pen according to claim 5, characterized in that: The outer wall of the prompting element (8) is provided with a second slot (82) for the third buckle (91) to engage, and the front and rear slot walls of the second slot (82) are provided with a third inclined surface (821) to facilitate the withdrawal of the third buckle (91).

7. An automatic injection pen according to claim 6, characterized in that: The outer wall of the prompting element (8) is provided with a sliding groove (83) that communicates with the second slot (82) for the third buckle (91) to slide back and forth.

8. An automatic injection pen according to any one of claims 2-7, characterized in that: The front end of the pen holder shell (1) is detachably connected to a cap (3) for fitting on the outside of the front end of the unlocking structure (6) to prevent accidental contact.

9. An automatic injection pen according to claim 8, characterized in that: The pre-filled syringe (2) is detachably connected to a needle cap (21) at its front end. The cap (3) is provided with a fourth buckle (31) that pulls the needle cap (21) out together when it is pulled out of the pen holder (1).

10. An automatic injection pen according to claim 9, characterized in that: The pen holder shell (1) is provided with an observation window (10) for observing the pre-filled syringe (2), and the inner edge of the observation window (10) is provided with a retainer (100) that cooperates with the fixed bracket (51) to restrict the movement of the pre-filled syringe (2).

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