Automatic injection pen release mechanism and automatic injection pen

Abstract

The utility model discloses an automatic injection pen releasing mechanism and an automatic injection pen, and relates to the technical field of medical instruments, the automatic injection pen releasing mechanism comprises a push rod, a needle locking sleeve and a first driving part; an axial cavity is formed in the lock pin sleeve, a holding and clamping part is arranged at the end of the lock pin sleeve, and an opening communicated with the axial cavity is formed in the holding and clamping part. The push rod is movably matched with the axial cavity and the holding and clamping part, and the push rod can axially move relative to the lock pin sleeve; the first driving piece is used for driving the push rod to extend out of the needle locking sleeve, and the push rod is used for pushing and injecting liquid medicine after extending out. According to the automatic injection pen releasing mechanism, by optimizing the structure, the radial displacement of the push rod is effectively limited, the accuracy of the injection dosage and the stability of the injection process are ensured, meanwhile, abnormal sounds are reduced, and the overall use experience is improved.

Description

Technical Field

[0001] This application relates to the field of medical device technology, and in particular to an automatic injection pen release mechanism and an automatic injection pen. Background Technology

[0002] An auto-injection pen is a portable drug delivery device used in the medical field, enabling patients to manage their own medication injections. One of the core components of this device is its release mechanism, which locks the plunger in its initial state and unlocks it when triggered by the user, thereby propelling the medication through the injection needle for accurate injection into the patient.

[0003] Currently, in automated injection pens, while the release mechanism allows the plunger to move axially along the internal space of the mechanism during unlocking, there is a risk of radial displacement when the plunger reaches its end position. This radial displacement can lead to inaccurate dosage or even injection failure, affecting the safety and effectiveness of drug delivery. Furthermore, radial displacement can cause unnecessary friction between internal components of the pen, generating abnormal noise and impacting the user experience. These issues reflect shortcomings in the structural design of existing release mechanisms, and their motion stability needs improvement. Utility Model Content

[0004] The purpose of this application is to provide an automatic injection pen release mechanism that, through optimized structure, effectively limits the radial displacement of the plunger, ensuring the accuracy of the injection dosage and the stability of the injection process, while reducing abnormal noise and improving the overall user experience. Another purpose of this application is to provide an automatic injection pen.

[0005] To achieve the above objectives, this application provides an automatic injection pen release mechanism, including a push rod, a locking needle sleeve, and a first driving member;

[0006] The locking pin sleeve has an axial cavity inside, and the end of the locking pin sleeve has a clamping part, and the clamping part has an opening that communicates with the axial cavity.

[0007] The push rod is movably engaged with the axial cavity and the clamping part, and the push rod can move axially relative to the locking pin sleeve;

[0008] The first driving member is used to drive the push rod to extend out of the locking needle sleeve, and the push rod is used to inject the liquid medicine after it extends.

[0009] In some embodiments, a pin guard assembly is further included, which is used to lock and unlock the push rod and the locking pin sleeve; when the push rod and the locking pin sleeve are unlocked, the first drive member drives the push rod to move.

[0010] In some embodiments, the locking pin sleeve has a hole; the pin guard assembly includes an inner body, which is sleeved on the outside of the locking pin sleeve, and the inner body has a first protrusion inside, which locks the inner body and the locking pin sleeve when the first protrusion is engaged with the hole.

[0011] In some embodiments, the hole is located in the clamping part; when the push rod is in the locking pin sleeve, the first protrusion is engaged in the hole; when the push rod is disengaged from the locking pin sleeve, the clamping part deforms inward, and the first protrusion disengages from the hole.

[0012] In some embodiments, the push rod has a slot; the needle guard assembly includes an inner body, the interior of which has a second protrusion, which locks the inner body and the push rod when the second protrusion engages with the slot.

[0013] In some embodiments, the outer side of the inner body is provided with a spring arm, which is connected to the second protrusion; the needle guard assembly further includes a release ring, which is sleeved on the outer side of the inner body and can move axially relative to the inner body; when the release ring abuts against the spring arm, the second protrusion is engaged in the groove; when the release ring disengages from the spring arm, the spring arm deforms outward and the second protrusion disengages from the groove.

[0014] In some embodiments, the locking pin sleeve has a movement window and a locking window; the pin protection assembly includes a pin protection sleeve, a second driving member and a release ring, the pin protection sleeve and the release ring are axially opposed, the release ring has a third protrusion inside, the third protrusion can move axially in the movement window, the second driving member is used to drive the release ring to drive the pin protection sleeve to move, and when the third protrusion is engaged in the locking window, the pin protection sleeve is in the pin protection position.

[0015] In some embodiments, the clamping portion includes a connected extension and an arcuate body, the extension being connected to the end of the locking pin sleeve, and the arcuate body extending circumferentially along the locking pin sleeve.

[0016] In some embodiments, the end of the locking pin sleeve is further provided with a bearing portion; the arc-shaped body is provided with a cut surface, and when the locking pin sleeve is demolded, the cut surface avoids the push rod, so that the push rod abuts against the bearing portion, and the locking pin sleeve is removed from the mold.

[0017] This application also provides an automatic injection pen, including a pen body, a pen cap, and the aforementioned automatic injection pen release mechanism. The automatic injection pen release mechanism is disposed on the pen body, and the pen cap is connected to the pen body. The pen body is used to install a pre-filled syringe, and the automatic injection pen release mechanism is used to eject the liquid medicine in the pre-filled syringe when the push rod moves.

[0018] Compared to the aforementioned background technology, the automatic injection pen release mechanism provided in this application mainly includes a push rod, a locking needle sleeve, and a first driving member; the locking needle sleeve has an axial cavity inside, and a clamping part is provided at the end of the locking needle sleeve, with an opening communicating with the axial cavity inside the clamping part; the push rod is movably engaged with the axial cavity and the clamping part, and the push rod can move axially relative to the locking needle sleeve; the first driving member is used to drive the push rod to extend out of the locking needle sleeve, and the push rod is used to inject the drug solution after extending.

[0019] In the design of automated injection pens, ensuring precise control of the plunger is crucial, as it directly affects the accuracy of the injection dosage and the reliability of the entire injection process. Defects mentioned in the background section, such as radial displacement of the plunger at the end of the release mechanism, can lead to dosage errors or injection failures, posing risks to the safety and effectiveness of patient treatment.

[0020] To address these technical challenges, this technical solution proposes an optimized automatic injection pen release mechanism. This mechanism includes a push rod, a locking needle sleeve, and a first drive component. Stable axial movement of the push rod is achieved through a carefully designed axial cavity inside the locking needle sleeve and an end clamping portion. The clamping portion design of the locking needle sleeve allows the push rod to move flexibly within it while ensuring that no unintended radial displacement occurs during injection.

[0021] The primary driving component provides power to ensure the plunger extends smoothly from the locking needle sleeve, a necessary step for drug injection. This movement of the plunger is precisely controlled, ensuring accurate dosage. The optimized fit between the plunger and the locking needle sleeve reduces unnecessary friction, thus minimizing potential noise during injection.

[0022] Based on the above structural and process descriptions, it can be seen that the automatic injection pen release mechanism has at least the following beneficial effects: Through optimized structure, the automatic injection pen release mechanism effectively limits the radial displacement of the push rod, ensuring the accuracy of the injection dosage and the stability of the injection process. Simultaneously, by reducing friction during movement, it also reduces abnormal noise, thereby improving the overall user experience. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0024] Figure 1 A schematic diagram of the automatic injection pen release mechanism and the automatic injection pen provided in the embodiments of this application;

[0025] Figure 2 A schematic diagram of the push rod and locking pin sleeve provided in the embodiments of this application. Figure 1 ;

[0026] Figure 3 A schematic diagram of the push rod and locking pin sleeve provided in the embodiments of this application. Figure 2 ;

[0027] Figure 4 A schematic diagram of the locking pin sleeve provided in an embodiment of this application;

[0028] Figure 5 Schematic diagram of the interior provided in the embodiments of this application Figure 1 ;

[0029] Figure 6 Schematic diagram of the interior provided in the embodiments of this application Figure 2 ;

[0030] Figure 7 Schematic diagram of the inner body and locking pin sleeve provided in the embodiments of this application Figure 1 ;

[0031] Figure 8 Schematic diagram of the inner body and locking pin sleeve provided in the embodiments of this application Figure 2 ;

[0032] Figure 9 A schematic diagram of the inner body and release ring provided in an embodiment of this application;

[0033] Figure 10 A schematic diagram showing the axial displacement of the release ring provided in the embodiments of this application;

[0034] Figure 11 A schematic diagram of the third protrusion, the locked window, and the motion window provided in the embodiments of this application;

[0035] Figure 12 An external view of the automatic injection pen provided in the embodiments of this application;

[0036] Figure 13 A perspective view of an automatic injection pen provided in an embodiment of this application;

[0037] Figure 14 This is a schematic diagram of a locking pin sleeve provided in another embodiment of this application.

[0038] in:

[0039] 1. Pen cap; 2. Front body; 3. Gasket; 4. Release ring; 5. Needle sleeve spring; 6. Rear body; 7. Needle sleeve; 8. Pre-filled syringe; 9. Push rod; 10. Push rod spring; 11. Spring guide rod; 12. Locking needle sleeve; 13. Inner body.

[0040] Third protrusion 41, groove 91, clamping part 121, hole 122, locking window 123, moving window 124, closed surface 125, bearing part 126, cut surface 127, spring arm 131, mating window 132, longitudinal rib 133, protrusion 134, support foot 135, anti-rotation block 136, second protrusion 137, first protrusion 138. Detailed Implementation

[0041] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0042] To enable those skilled in the art to better understand the present application, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0043] Please refer to Figures 1 to 3 ,in, Figure 1 This is a schematic diagram of the automatic injection pen release mechanism and the automatic injection pen provided in the embodiments of this application. Figure 2 A schematic diagram of the push rod and locking pin sleeve provided in the embodiments of this application. Figure 1 , Figure 3 A schematic diagram of the push rod and locking pin sleeve provided in the embodiments of this application. Figure 2 .

[0044] It should be noted that, in this application, the proximal end is the direction closest to the needle, i.e. towards the injection site, with the automatic injection pen as the reference object; the distal end is the direction opposite to the proximal end, i.e. away from the injection site.

[0045] In a first specific embodiment, the automatic injection pen release mechanism provided by the present application mainly includes a push rod 9, a locking needle sleeve 12, and a first driving member; the locking needle sleeve 12 has an axial cavity inside, and a clamping part 121 is provided at the end of the locking needle sleeve 12, with an opening communicating with the axial cavity inside the clamping part 121; the push rod 9 is movably engaged with the axial cavity and the clamping part 121, and the push rod 9 can move axially relative to the locking needle sleeve 12; the first driving member is used to drive the push rod 9 to extend out of the locking needle sleeve 12, and the push rod 9 is used to inject the drug solution after extending.

[0046] In some cases, the clamping part 121 is located at the proximal end of the locking pin sleeve 12, so the opening formed by the clamping part 121 is located at the proximal end of the locking pin sleeve 12. The axial cavity in the locking pin sleeve 12 communicates with the opening at the proximal end. The distal end of the locking pin sleeve 12 is closed, and the axial cavity is a single-opening form. The push rod 9 is inserted from the proximal end of the locking pin sleeve 12 and moves axially at the proximal end of the locking pin sleeve 12.

[0047] like Figure 2 As shown, the push rod 9 moves relative to the locking pin sleeve 12. The push rod 9 has exited the axial cavity, and its distal end is located in the clamping part 121. After the axial cavity is released, the push rod 9 is still restricted by the clamping part 121, thereby achieving the purpose of limiting the radial displacement of the push rod 9. Since the clamping part 121 is an additional structure set at the proximal end of the locking pin sleeve 12, this design also enhances the structural strength of the proximal end of the locking pin sleeve 12. Figure 3 As shown, as the push rod 9 moves further relative to the locking needle sleeve 12, the push rod 9 further retracts from the clamping part 121, and the end of the push rod 9, i.e. the distal end, is completely retracted from the locking needle sleeve 12. Since the extension length of the push rod 9 is sufficient to complete the injection requirements, the push rod 9 no longer needs to be restricted by radial offset at this time.

[0048] It should be noted that the radial restriction of the push rod 9 by the axial cavity and the clamping part 121 includes radial restriction at any circumferential angle position. However, the structural form of the axial cavity and the clamping part 121 is not limited here. For example, it can be a structure that fully wraps around the circumference of the push rod 9, such as a closed cylindrical structure, or a structure that partially wraps around the circumference, such as a hollow cylindrical structure. As long as it can achieve full-angle restriction, it should also be within the scope of this embodiment.

[0049] In the design of an automated injection pen, ensuring precise control of the plunger 9 is crucial, as it directly affects the accuracy of the injection dosage and the reliability of the entire injection process. Defects mentioned in the background section, such as radial displacement of the plunger 9 at the end of the release mechanism, can lead to dosage errors or injection failures, posing risks to the safety and effectiveness of patient treatment.

[0050] To address these technical issues, this technical solution proposes an optimized automatic injection pen release mechanism. This mechanism includes a push rod 9, a locking needle sleeve 12, and a first drive component. Stable axial movement of the push rod 9 is achieved through a carefully designed axial cavity inside the locking needle sleeve 12 and an end clamping portion 121. The clamping portion 121 of the locking needle sleeve 12 is designed to allow the push rod 9 to move flexibly within it, while ensuring that no unintended radial displacement occurs during injection.

[0051] The first driving component provides power to ensure that the push rod 9 can smoothly extend from the locking needle sleeve 12, a prerequisite for drug injection. This movement of the push rod 9 is precisely controlled, thus ensuring the accuracy of the injection dosage. Because the fit between the push rod 9 and the locking needle sleeve 12 is optimized, unnecessary friction between them is reduced, thereby reducing potential abnormal noises during injection.

[0052] Based on the above structural and process descriptions, it can be seen that the automatic injection pen release mechanism has at least the following beneficial effects: Through structural optimization, the automatic injection pen release mechanism effectively limits the radial displacement of the push rod 9, ensuring the accuracy of the injection dosage and the stability of the injection process. Simultaneously, by reducing friction during movement, it also reduces abnormal noise, thereby improving the overall user experience.

[0053] It should be noted that the improvement of the automatic injection pen release mechanism provided in this embodiment lies in the dual radial restriction of the push rod 9 by the axial cavity and the clamping part 121. In particular, the clamping part 121 is used to restrict the radial displacement of the push rod 9 when the end of the push rod 9 is about to disengage from the locking needle sleeve 12. Apart from this, this embodiment does not limit the triggering principle of the automatic injection pen release mechanism, such as how to put the automatic injection pen release mechanism into the triggered state, and then drive the push rod 9 to move through the first driving member for injection. Other contents, including this, can be referred to the prior art, and will not be described in detail here.

[0054] In some embodiments, the number of clamping parts 121 is a pair, and the pair of clamping parts 121 are symmetrically arranged along the circumference of the locking pin sleeve 12.

[0055] In this embodiment, the clamping portions 121 are designed as a pair. This configuration is intended to provide better symmetry and balance, ensuring more stable and reliable functioning of the locking pin sleeve 12. The pair of clamping portions 121 are symmetrically arranged along the circumference of the locking pin sleeve 12, meaning they are evenly distributed in the circumferential direction of the locking pin sleeve 12, achieving full-angle restraint while providing uniform force.

[0056] Please continue to refer to this. Figure 4 In some embodiments, the clamping part 121 includes a connected extension and an arcuate body, the extension being connected to the end of the locking pin sleeve 12, and the arcuate body extending circumferentially along the locking pin sleeve 12.

[0057] In this embodiment, the extension is directly connected to the end of the locking pin sleeve 12, providing a fixed point, while the arc-shaped body extends circumferentially along the locking pin sleeve 12. This design allows the clamping part 121 to flexibly adapt to changes in the shape of the locking pin sleeve 12 and the push rod 9, while the arc-shaped body provides the necessary space and guidance when the push rod 9 moves axially.

[0058] This structural design not only enhances the stability of the interaction between the locking needle sleeve 12 and the push rod 9, but also helps improve the overall mechanical performance and service life of the injection pen. Through this carefully designed clamping part 121, the movement of the push rod 9 can be more precisely controlled during use, thereby ensuring the safety and effectiveness of drug injection.

[0059] Specifically, in the circumferential direction of the locking pin sleeve 12, there is a gap between the arc-shaped bodies of a pair of clamping parts 121 to meet the space requirements of the circumferential side when the clamping parts 121 undergo elastic deformation in the radial direction.

[0060] Please refer to Figure 14 , Figure 14 This is a schematic diagram of a locking pin sleeve provided in another embodiment of this application.

[0061] Optionally, the end of the locking pin sleeve 12 is also provided with a bearing portion 126; the arc-shaped body is provided with a cut surface 127, which avoids the push rod when the locking pin sleeve 12 is demolded, so that the push rod abuts against the bearing portion 126 and removes the locking pin sleeve 12 from the mold.

[0062] Specifically, the supporting part 126 is located between a pair of clamping parts 121. The function of the supporting part 126 is to contact the push rod, facilitating the push rod to push the locking pin sleeve 12 out of the mold. Because the contact point of the push rod is the supporting part 126, contact between the push rod and the clamping parts 121 is avoided. Therefore, the clamping parts 121 will not be deformed by force during the demolding process of the locking pin sleeve 12, thus improving the risk of deformation of the locking pin sleeve 12 during demolding. The cut surface 127 is a feature on the arc-shaped body, which is equivalent to cutting the clamping parts 121 at the proximal position, so that the push rod can extend and retract freely, avoiding the clamping parts 121 from obstructing the movement of the push rod.

[0063] In some cases, such as Figure 14 As shown, a pair of adjacent cut surfaces 127 are set as planes that overlap after extension. In the circumferential direction of the locking pin sleeve 12, a circumferential distance C is left between the pair of cut surfaces 127 to facilitate the action of the push rod. Along the axial direction of the locking pin sleeve 12, this plane is projected onto the support portion 126. In the radial direction of the locking pin sleeve 12, this plane is located inside the support portion 126. A radial distance R is left between the cut surfaces 127 and the support portion 126 to facilitate the action of the push rod.

[0064] Please refer to Figure 4 , Figure 4 This is a schematic diagram of the locking pin sleeve provided in an embodiment of this application.

[0065] like Figure 4 As shown, the locking pin sleeve 12 is provided with a clamping part 121, a hole 122, a locking window 123, a moving window 124, and a closing surface 125. In some cases, the clamping part 121 and the hole 122 are located at the proximal end of the locking pin sleeve 12, the locking window 123 is located near the proximal end, the moving window 124 is located near the distal end, and the closing surface 125 is located at the distal end.

[0066] Please refer to Figure 5 and Figure 6 , Figure 5 Schematic diagram of the interior provided in the embodiments of this application Figure 1 , Figure 6Schematic diagram of the interior provided in the embodiments of this application Figure 2 .

[0067] like Figure 5 and Figure 6 As shown, the inner body 13 is provided with a spring arm 131, a mating window 132, a longitudinal rib 133, a protrusion 134, a support leg 135, an anti-rotation block 136, a second protrusion 137, and a first protrusion 138. In some cases, the protrusion 134, the support leg 135, and the anti-rotation block 136 are located at the proximal end of the inner body 13, the spring arm 131, the second protrusion 137, and the first protrusion 138 are arranged close to the proximal end, the spring arm 131 and the second protrusion 137 are on the inner body 13 with one outside and one inside, the first protrusion 138 is closer to the proximal end than the second protrusion 137, the mating window 132 and the longitudinal rib 133 are located between the proximal end and the distal end, and the mating window 132 and the longitudinal rib 133 are arranged at intervals along the circumference.

[0068] In one specific embodiment, the automatic injection pen release mechanism further includes a needle guard assembly, which is used to lock and unlock the push rod 9 and the locking needle sleeve 12; when the push rod 9 and the locking needle sleeve 12 are unlocked, the first driving member drives the push rod 9 to move.

[0069] In this embodiment, the needle protector assembly is designed to improve the safety and operational accuracy of the auto-injection pen. This assembly is responsible for locking the plunger 9 and the needle sleeve 12 before injection, preventing unintended injections due to accidental contact. When the user is ready to inject, the unlocking mechanism of the needle protector assembly is triggered by an operation, unlocking the plunger 9 and the needle sleeve 12.

[0070] In the locked state, the first actuator, which can be an elastic actuator such as a spring or similar elastic element, is designed to be in a stored state. It does not exert any movement on the push rod 9 because the positions of the push rod 9 and the locking needle sleeve 12 are fixed. This design ensures the safety of the injection pen when it is not unlocked, preventing any unintended injection actions.

[0071] Once the unlocking action occurs, the elastic actuator releases its stored energy, rapidly driving the plunger 9 to move axially, thus injecting the medication. This design not only improves the safety of the injection pen but also ensures rapid and accurate injection, providing users with a more reliable and convenient experience. In this way, the injection pen design simultaneously meets the requirements of both safety and functionality.

[0072] Please refer to Figure 7 and Figure 8 , Figure 7 Schematic diagram of the inner body and locking pin sleeve provided in the embodiments of this application Figure 1 , Figure 8 Schematic diagram of the inner body and locking pin sleeve provided in the embodiments of this application Figure 2 .

[0073] In some embodiments, the locking pin sleeve 12 is provided with a hole 122; the pin guard assembly includes an inner body 13, which is sleeved on the outside of the locking pin sleeve 12. The inner body 13 is provided with a first protrusion 138 inside, and the inner body 13 locks with the locking pin sleeve 12 when the first protrusion 138 is engaged with the hole 122.

[0074] In this embodiment, the locking pin sleeve 12 is designed with a hole 122 to achieve a mating and locking mechanism with the pin guard assembly. The pin guard assembly includes an inner body 13, which is designed to fit over the outside of the locking pin sleeve 12. The inner body 13 is characterized by a first protrusion 138, which plays a key structural role because it can interact with the hole 122 on the locking pin sleeve 12.

[0075] When the first protrusion 138 accurately engages with the hole 122, a locked state is formed between the inner body 13 and the locking needle sleeve 12, ensuring the safety and stability of the injection pen before use. This locking mechanism prevents the plunger 9 from extending accidentally without being triggered, thus ensuring that the medication is not injected unexpectedly. At the same time, this design simplifies the operation of the needle protector assembly, allowing the user to unlock and trigger the injection action with a simple operation when injection is needed.

[0076] It should be noted that in the mating relationship between the first protrusion 138 and the hole 122, since the inner body 13 is fitted outside the locking pin sleeve 12, the first protrusion 138 is located inside the inner body 13 and protrudes inward. The locking pin sleeve 12 is provided with the hole 122 instead of the protrusion, thus avoiding the method of providing an outward protrusion on the locking pin sleeve 12. This design avoids the risk of deformation caused by compression during storage of the locking pin sleeve 12 and improves safety and reliability.

[0077] Please refer to Figure 9 , Figure 9 This is a schematic diagram of the inner body and release ring provided in an embodiment of this application.

[0078] In some embodiments, the hole 122 is provided in the clamping part 121; when the push rod 9 is in the locking pin sleeve 12, the first protrusion 138 is engaged in the hole 122; when the push rod 9 is disengaged from the locking pin sleeve 12, the clamping part 121 deforms inward and the first protrusion 138 is disengaged from the hole 122.

[0079] In this embodiment, the clamping part 121 has an elastic structure. This design allows the clamping part 121 to undergo necessary elastic deformation in different states to adapt to the movement of the push rod 9 and the locking and unlocking requirements of the locking pin sleeve 12. The hole 122 is provided in the clamping part 121 to receive the first protrusion 138 and realize the locking between the push rod 9 and the locking pin sleeve 12.

[0080] When the push rod 9 is inside the locking needle sleeve 12, the first protrusion 138 inserts into the hole 122. At this time, the clamping part 121 maintains its original shape, ensuring the safety of the injection pen when it is not activated. When an injection operation is required and the push rod 9 begins to disengage from the locking needle sleeve 12, the clamping part 121 deforms inward using its elastic properties. This deformation causes the first protrusion 138, which was originally stuck in the hole 122, to disengage, thereby unlocking the locking needle sleeve 12 from the inner body 13. This design, which utilizes the elastic deformation of the clamping part 121, not only simplifies the unlocking mechanism but also improves the reliability of the unlocking process and the overall stability of the injection pen.

[0081] Please refer to Figure 10 , Figure 10 This is a schematic diagram showing the axial displacement of the release ring provided in the embodiment of this application.

[0082] In some embodiments, the push rod 9 is provided with a slot 91; the needle guard assembly includes an inner body 13, and the inner body 13 is provided with a second protrusion 137 inside, and the inner body 13 and the push rod 9 are locked when the second protrusion 137 is engaged in the slot 91.

[0083] In this embodiment, the push rod 9 is designed with a slot 91 to interact with the inner body 13 in the needle assembly, enabling the locking and unlocking functions of the push rod 9. The inner body 13 has an internal structure that includes a second protrusion 137, which is used to mate with the slot 91 on the push rod 9. When the second protrusion 137 is inserted into and engaged with the slot 91, a locked state is formed between the inner body 13 and the push rod 9, ensuring that the push rod 9 remains fixed within the injection pen and does not move or trigger accidentally.

[0084] This locking mechanism is crucial for the safety of the injection pen because it prevents injection at inappropriate times or locations. Only when an injection is needed does the user disengage the second protrusion 137 from the slot 91 by operating the needle guard assembly, thereby unlocking the push rod 9 and allowing it to move axially under the drive of the first actuator to complete the drug injection. This design not only improves the safety of the injection pen but also ensures the accuracy and reliability of the injection operation.

[0085] In some embodiments, the inner body 13 is provided with a spring arm 131 on the outside, and the spring arm 131 is connected to the second protrusion 137; the needle guard assembly also includes a release ring 4, which is sleeved on the outside of the inner body 13 and can move axially relative to the inner body 13; when the release ring 4 abuts against the spring arm 131, the second protrusion 137 is engaged in the groove 91; when the release ring 4 is disengaged from the spring arm 131, the spring arm 131 deforms outward and the second protrusion 137 is disengaged from the groove 91.

[0086] In this embodiment, similar to the deformation principle of the clamping part 121, the spring arm 131 is an elastic structure. The design of the spring arm 131 allows it to undergo elastic deformation when subjected to operating force, thereby realizing the locking and unlocking of the push rod 9.

[0087] The movement of the release ring 4 is closely related to the position and state of the spring arm 131. When the release ring 4 contacts and abuts against the spring arm 131, the spring arm 131 is subjected to a pushing force, causing the second protrusion 137 to engage with the groove 91 on the push rod 9, forming a locked state. At this time, the push rod 9 is fixed and will not move.

[0088] Conversely, when the release ring 4 disengages from the spring arm 131, the spring arm 131 deforms outward due to its elasticity. This deformation causes the second protrusion 137 to disengage from the slot 91. At this point, the push rod 9 is unlocked and can move axially within the injection pen to complete the injection action. This design cleverly utilizes the elastic properties of the spring arm 131 and the relative movement of the release ring 4 to achieve precise control of the push rod 9, ensuring the safety and reliability of the injection pen operation.

[0089] Please refer to Figure 11 , Figure 11 This is a schematic diagram of the third protrusion and the locked window and the motion window provided in the embodiments of this application.

[0090] In some embodiments, the locking pin sleeve 12 is provided with a movement window 124 and a locking window 123; the pin protection assembly includes a pin protection sleeve 7, a second driving member and a release ring 4, the pin protection sleeve 7 and the release ring 4 are axially opposed, the release ring 4 is provided with a third protrusion 41 inside, the third protrusion 41 can move axially in the movement window 124, the second driving member is used to drive the release ring 4 to drive the pin protection sleeve 7 to move, when the third protrusion 41 is engaged in the locking window 123, the pin protection sleeve 7 is in the pin protection position.

[0091] In this embodiment, the locking pin sleeve 12 is designed with a movement window 124 and a locking window 123, both of which play a crucial role in the operation of the pin protector assembly. The movement window 124 allows the third protrusion 41 inside the release ring 4 to move axially within it, while the locking window 123 is used to lock the pin protector sleeve 7 in a specific position.

[0092] The needle protection assembly includes a needle sheath 7, a second drive member, and a release ring 4. The needle sheath 7 and the release ring 4 are axially opposed to each other, forming a pair of interacting components. The third protrusion 41 inside the release ring 4 can move freely in the motion window 124. This movement is controlled by the second drive member. After the injection is completed, the second drive member drives the release ring 4, which in turn drives the needle sheath 7 to perform a corresponding axial movement. When the third protrusion 41 moves to the locking window 123 and engages there, the needle sheath 7 is locked in the needle protection position, protecting the needle tip inside.

[0093] In some cases, the second drive element can also be an elastic drive element.

[0094] Please refer to Figure 12 and Figure 13 ,in, Figure 12 This is an external view of the automatic injection pen provided in an embodiment of this application. Figure 13 A perspective view of an automatic injection pen provided in an embodiment of this application.

[0095] This application also provides an automatic injection pen, including a pen body, a pen cap 1, and the aforementioned automatic injection pen release mechanism. The automatic injection pen release mechanism is located on the pen body, and the pen cap 1 is connected to the pen body. The pen body is used to install a pre-filled syringe 8, and the automatic injection pen release mechanism is used to push out the liquid medicine in the pre-filled syringe 8 when the push rod 9 moves.

[0096] In some embodiments, the pen body includes a front body 2 and a rear body 6 connected together; the automatic injection pen release mechanism includes an inner body 13, which is disposed on the rear body 6.

[0097] In some cases, the first driving component can be a push rod spring 10, which is located between the push rod 9 and the locking pin sleeve 12; the second driving component can be a protective pin sleeve spring 5, which is located between the release ring 4 and the rear body 6. Figure 1 The automatic injection pen includes a pen cap 1, a front body 2, a gasket 3, a release ring 4, a needle sleeve spring 5, a rear body 6, a needle sleeve 7, a pre-filled syringe 8, a push rod 9, a push rod spring 10, a spring guide rod 11, a locking needle sleeve 12, and an inner body 13.

[0098] The locking needle sleeve 12 can be a cylindrical structure, with the closed surface 125 located at the distal end of the locking needle sleeve 12. Its inner surface abuts against the spring guide rod 11, and its other surface abuts against the inner surface of the rear body 6 after injection. After injection, the locking needle sleeve 12 will move to the distal position, while the release ring 4 will move towards the proximal end under the action of the needle sleeve spring 5. Thus, the third protrusion 41 of the release ring 4 will engage with the locking window 123, and the release ring 4 will be restricted by the barrier between the locking window 123 and the moving window 124 of the locking needle sleeve 12, and thus cannot move further to the distal axial position.

[0099] The inner body 13 can be a tubular structure with open ends, and is completely fixed to the rear body 6. The longitudinal rib 133 engages with the longitudinal groove on the inner side of the release ring 4 to limit the radial positioning of the release ring 4 on the inner body 13. The protrusion 134 is loosely fitted with the symmetrical small square opening at the proximal end of the release ring 4, serving as the positioning when the release ring 4 is in the proximal position on the inner body 13. The window 132 allows the third protrusion 41 of the release ring 4 to pass through, providing space for axial movement.

[0100] In one specific implementation, the instructions for using the automatic injection pen are as follows.

[0101] Before use, the push rod spring 10 is housed between the push rod 9 and the locking pin sleeve 12; wherein the spring guide rod 11 passes through the hollow part inside the push rod spring 10 to guide the push rod spring 10 and reduce its deformation in the compressed state; the inner body 13 is fixed as a fixing member to the opening near the end of the rear body 6, and a release ring 4 that can move axially along the inner body 13 is arranged on its outer side; the release ring 4 wraps around the inner body 13 to prevent the spring arm 131 from spreading outward, thereby limiting the axial movement of the push rod 9.

[0102] When the injection pen is in the activation process, the hole 122 of the locking needle sleeve 12 engages with the first protrusion 138 of the inner body 13, and at the same time, the release ring 4 abuts against the spring arm 131. The push rod 9 is restricted from radial displacement outward by the second protrusion 137 of the inner body 13, so it remains in the axial position of the inner body 13.

[0103] Press the needle sheath 7 against the injection site. The needle sheath 7 pushes the release ring 4 to move to the rear end. At this time, the release ring 4 disengages from the spring arm 131. The second protrusion 137 of the inner body 13 loses the restriction that it is restricted from making radial displacement outward. The second protrusion 137 springs outward, and the push rod 9 moves towards the proximal end under the action of the push rod spring 10.

[0104] When the push rod 9 makes a proximal axial displacement, and a section of the distal end is still within the range of the inner body 13, the clamping part 121 at the proximal end of the locking needle sleeve 12 can still cover the distal part of the push rod 9, reducing the sway of the push rod 9 and reducing the friction between the push rod 9 and other parts during the injection process due to the increased radial space, which would cause abnormal noise.

[0105] When the push rod 9 is completely disengaged from the inner diameter of the inner body 13, the axial position of the locking pin sleeve 12, which was originally restricted by the first protrusion 138 at the proximal end of the inner body 13, will be freed up due to the complete disengagement of the push rod 9. The clamping part 121 at the proximal end of the locking pin sleeve 12 can deform inward and break free from the restriction of the first protrusion 138 of the inner body 13. This allows the locking pin sleeve 12 to move to the distal end under the action of the push rod spring 10. At this time, the outer diameter of the locking pin sleeve 12 will interfere with the first protrusion 138 of the inner body 13 and make a sound. When it moves to the rear body 6, it will also make a sound.

[0106] After the injection is completed, the injection pen is lifted away from the injection site. The release ring 4 is then moved axially towards the proximal end by the action of the needle sleeve spring 5. When the third protrusion 41 of the release ring 4 is engaged in the locking window 123, the locking sleeve 12 then limits the release ring 4 to move to the distal end, thereby protecting the exposed needle tip.

[0107] It should be noted that many of the components mentioned in this application are general standard parts or components known to those skilled in the art, and their structure and principle can be learned by those skilled in the art through technical manuals or through conventional experimental methods.

[0108] It should be noted that in this specification, relational terms such as first and second are used only to distinguish one entity from several other entities, and do not necessarily require or imply any such actual relationship or order between these entities.

[0109] The above provides a detailed description of the automatic injection pen release mechanism and the automatic injection pen provided in this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and core ideas of this application. It should be noted that those skilled in the art can make various improvements and modifications to this application without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of this application.

Claims

1. An automatic injection pen release mechanism, characterized in that, Includes push rod, locking pin sleeve and first drive component; The locking pin sleeve has an axial cavity inside, and the end of the locking pin sleeve has a clamping part, and the clamping part has an opening that communicates with the axial cavity. The push rod is movably engaged with the axial cavity and the clamping part, and the push rod can move axially relative to the locking pin sleeve; The first driving member is used to drive the push rod to extend out of the locking needle sleeve, and the push rod is used to inject the liquid medicine after it extends.

2. The automatic injection pen release mechanism according to claim 1, characterized in that, It also includes a pin guard assembly, which is used to lock and unlock the push rod and the locking pin sleeve; when the push rod and the locking pin sleeve are unlocked, the first drive member drives the push rod to move.

3. The automatic injection pen release mechanism according to claim 2, characterized in that, The locking pin sleeve has a hole; the pin guard assembly includes an inner body, which is sleeved on the outside of the locking pin sleeve. The inner body has a first protrusion inside, and the inner body locks with the locking pin sleeve when the first protrusion is engaged with the hole.

4. The automatic injection pen release mechanism according to claim 3, characterized in that, The hole is located in the clamping part; when the push rod is in the locking pin sleeve, the first protrusion is inserted into the hole; when the push rod is removed from the locking pin sleeve, the clamping part deforms inward, and the first protrusion is removed from the hole.

5. The automatic injection pen release mechanism according to claim 2, characterized in that, The push rod has a slot; the needle guard assembly includes an inner body, and the interior of the inner body has a second protrusion. When the second protrusion is engaged in the slot, the inner body and the push rod are locked together.

6. The automatic injection pen release mechanism according to claim 5, characterized in that, The inner body is provided with a spring arm on its outside, and the spring arm is connected to the second protrusion; the needle guard assembly also includes a release ring, which is sleeved on the outside of the inner body and can move axially relative to the inner body; when the release ring abuts against the spring arm, the second protrusion is engaged in the groove; when the release ring disengages from the spring arm, the spring arm deforms outward and the second protrusion disengages from the groove.

7. The automatic injection pen release mechanism according to claim 2, characterized in that, The locking pin sleeve has a movement window and a locking window; the pin protection assembly includes a pin protection sleeve, a second driving member and a release ring, the pin protection sleeve and the release ring are axially opposed, the release ring has a third protrusion inside, the third protrusion can move axially in the movement window, the second driving member is used to drive the release ring to drive the pin protection sleeve to move, when the third protrusion is engaged in the locking window, the pin protection sleeve is in the pin protection position.

8. The automatic injection pen release mechanism according to any one of claims 1 to 7, characterized in that, The clamping part includes a connected extension body and an arc-shaped body. The extension body is connected to the end of the locking pin sleeve, and the arc-shaped body extends circumferentially along the locking pin sleeve.

9. The automatic injection pen release mechanism according to claim 8, characterized in that, The end of the locking pin sleeve is also provided with a bearing part; the arc-shaped body is provided with a cut surface, and when the locking pin sleeve is demolded, the cut surface avoids the push rod, so that the push rod abuts against the bearing part and removes the locking pin sleeve from the mold.

10. An automatic injection pen, characterized in that, The device includes a pen body, a pen cap, and an automatic injection pen release mechanism as described in any one of claims 1 to 9, wherein the automatic injection pen release mechanism is disposed on the pen body, the pen cap is connected to the pen body, the pen body is used to mount a pre-filled syringe, and the automatic injection pen release mechanism is used to eject the liquid medicine in the pre-filled syringe when the push rod is moved.

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