A reusable auto-injector

Abstract

This invention relates to a reusable autoinjector, belonging to the field of drug injection technology. The reusable autoinjector provided by this invention, through the systematic integration of an innovative anti-accidental contact mechanism and a needle depth adjustment mechanism, not only effectively solves the core safety and accuracy challenges in reusable scenarios, but also produces significant technical effects through the synergistic effect of the two mechanisms. It is the first invention to integrate two major functions—active mechanical anti-accidental contact and multi-level stable depth adjustment—into a single reusable device.

Description

Technical Field

[0001] This invention relates to a reusable automatic injector, belonging to the field of drug injector technology. Background Technology

[0002] As a core device for clinical diagnosis, drug injection, and home self-administration, the precision, safety, and reliability of syringe operation are of paramount importance. With advancements in medical technology and the increasing prevalence of chronic disease self-management, the demand for safe and reliable reusable injection devices is growing. These devices not only require excellent durability and sterilizability but also must ensure the stability and controllability of each injection action throughout complex reusable procedures.

[0003] However, very few reusable syringes in the current technology can truly meet the above requirements. Commercially available designs often focus on the mechanical durability of the structure, neglecting the human-machine interface safety and precision control issues in two crucial aspects during the reuse cycle, leading to significant deficiencies in practical applications.

[0004] First, there is a general lack of effective mechanisms to prevent accidental activation during the reset safety process. Many reusable syringes currently use spring-driven mechanisms for stable injection, typically with the injection spring integrated into the plunger. After each injection, the user must manually pull the plunger back to recompress and recharge the injection spring for the next use. However, in this reset state, the plunger and the trigger button (or trigger) for the spring are usually in a "ready-to-fire" state without locking. This design presents a serious safety hazard: when the device is subjected to accidental impact, pressure, or jolting during storage or transport, the button can be easily triggered or the plunger moved directly, causing the injection spring to release energy unexpectedly. This accidental triggering not only destroys the stored driving force, causing the next injection to fail due to insufficient thrust, but can also lead to safety issues such as sudden needle extension and medication splashing, significantly reducing the reliability of the reusable device and the operator's personal safety. In addition, since the reset needs to be performed multiple times, the coordination between the anti-accidental touch device and the injection button during the reset process also needs to be carefully designed. It is necessary to ensure that the movement of the injection button during the reset process is not affected by the anti-accidental touch device. Otherwise, multiple resets will cause the injection button to wear out and become unable to continue working.

[0005] Secondly, there is a serious lack of stable and adjustable needle depth control mechanisms in the injection accuracy stage. Different drugs (such as subcutaneous insulin, intramuscular antibiotics, and intradermal vaccines) have millimeter-level precision requirements for needle depth. Most existing reusable syringes are still designed with the concept of "push injection" itself in mind, relying entirely on the user's personal experience and feel for visual estimation and manual control of needle depth. This rough operation method, in the hands of users with varying levels of skill, can easily lead to needles being inserted too deeply or too shallowly, resulting in poor drug efficacy, local tissue damage, or increased pain. Although a few devices on the market have a depth adjustment concept, their adjustment structure is often relatively simple (such as a simple threaded adjustment), with problems such as vague adjustment levels, insecure locking, and accidental slippage under injection pressure, failing to provide a lasting and stable depth maintenance function in multiple cycles of repeated use.

[0006] More importantly, the two aforementioned shortcomings are often addressed and resolved in isolation in existing technologies. Some solutions may attempt to add simple anti-accidental touch locks, while others may try to improve the depth adjustment ring. However, a systematic solution that integrates reset safety locking with precise injection depth control is lacking. Such isolated improvements typically result in structural complexity, cumbersome operation procedures, and potential interference between functional modules in their timing. This fails to fundamentally achieve a high-performance reusable injection device that is both safe and error-proof, and can accurately adapt to different injection scenarios.

[0007] Therefore, there is an urgent need in the field for a reusable autoinjector that can solve the above problems. Summary of the Invention

[0008] To address the above problems, the present invention provides a reusable automatic injector, comprising: An injection assembly includes a top shell, an injection button, an injection spring, a plunger, and an anti-accidental press mechanism. The anti-accidental press mechanism includes: an anti-accidental press member with a button window on one side and a button limiting block at the rear end of the button window; an anti-accidental press boss on the other side of the anti-accidental press member; an anti-accidental press spring abutting against the rear end of the anti-accidental press member, providing a biasing force to hold the button limiting block below the injection button; and a rotatable stop arm driven by a metal torsion spring. The button limiting block is located below the injection button to prevent accidental presses when not injecting. The plunger is movably sleeved on the front of the injection spring. During injection, the anti-accidental touch component is pushed backward, the button limiting block is pushed away from the lower part of the injection button, and the button window reaches the lower part of the injection button. After injection, the stop spring arm abuts against the anti-accidental touch boss, and the button window remains at the lower part of the injection button. After injection, when the plunger is pushed backward to reset, the plunger presses down on the stop spring arm, the stop spring arm disengages from the anti-accidental touch boss, and the button limiting block returns to the lower part of the injection button under the action of the anti-accidental touch spring. The needle insertion depth adjustment mechanism includes a lower shell and a hidden needle component, wherein the hidden needle component rotates relative to the lower shell to adjust different needle insertion depths.

[0009] In some embodiments of the present invention, the inner wall of the front end of the lower shell is provided with a first stepped limiting platform, the front end of the first stepped limiting platform having a plurality of first stepped contact surfaces located at different axial heights; the surface of the hidden needle is provided with a second stepped limiting platform, the second stepped limiting platform having a plurality of second stepped contact surfaces that cooperate with the first stepped contact surfaces; during injection, the hidden needle moves inward relative to the lower shell, and the first stepped contact surfaces engage with the second stepped contact surfaces; when adjusting the needle insertion depth, the hidden needle rotates relative to the lower shell, and after rotation, the engagement position of the first stepped contact surfaces and the second stepped contact surfaces during injection changes, thereby adjusting different needle insertion depths.

[0010] In some embodiments of the present invention, the reusable autoinjector further includes: a concealed needle mating member, the front end of which is connected to the inner periphery of the concealed needle member, the concealed needle mating member being axially fixed to the concealed needle member; a concealed needle spring, the concealed needle spring providing a spring force that biases the concealed needle mating member forward; an insertion member slidable relative to the lower housing; and a pre-filled syringe (PFS) detachably disposed within the insertion member.

[0011] In some embodiments of the present invention, the needle insertion member is provided with a sliding limiting groove, and the two ends of the sliding limiting groove are respectively provided with a front limiting snap-fit ​​member and a rear limiting snap-fit ​​member. The lower shell is provided with a buckle, and the buckle cooperates with the front limiting snap-fit ​​member and the rear limiting snap-fit ​​member to limit the travel of the needle insertion member relative to the lower shell. In some embodiments of the present invention, the inner wall of the concealed needle mating part is provided with a first concealed needle spring limiting surface, and the rear end of the needle insertion part is provided with a second concealed needle spring limiting surface opposite to the first concealed needle spring limiting surface. The two ends of the concealed needle spring respectively abut against the first concealed needle spring limiting surface and the second concealed needle spring limiting surface.

[0012] In some embodiments of the present invention, a hook is provided at the front end of the injection button, and a hanging hole is provided on the plunger to cooperate with the hook.

[0013] In some embodiments of the present invention, the reusable auto-injector further includes a frame. After injection, when the plunger is pushed back to reset, the plunger presses down on the stop spring arm, the stop spring arm disengages from the anti-accidental contact boss, and the anti-accidental contact component moves forward under the action of the anti-accidental contact spring and collides with the frame to produce a sound. In some embodiments of the present invention, a stop block is provided on the plunger. After the injection is completed, when the plunger is pushed back to reset, the stop block presses down on the stop spring arm, and the stop spring arm disengages from the anti-accidental contact boss. The anti-accidental contact component is a long cylindrical structure partially sleeved on the outside of the plunger, and a strip groove is provided on the anti-accidental contact component for the stop block to pass through. In some embodiments of the present invention, the upper shell of the injection assembly is provided with a window, and the plunger is marked with an indicator indicating injection in progress and injection completion, the indicator being displayed in the window.

[0014] In some embodiments of the present invention, the inner circumference of the hidden needle is detachably connected to a cap remover, and the hidden needle is rotated by rotating the cap remover; the pfs is provided with a needle cap, and the front end of the cap remover is provided with a claw that engages with the needle cap. When the cap remover is pulled outward, the claw will grab the needle cap and pull it outward together.

[0015] In some embodiments of the present invention, the front section of the concealed needle mating part is provided with a concealed needle mating groove, and the inner surface of the concealed needle part is provided with a concealed needle limiting ring that mates with the concealed needle mating groove; the mating between the concealed needle part and the concealed needle mating part allows them to rotate relative to each other, but they are fixed to each other in the axial direction, that is, they move together in the axial direction.

[0016] In some embodiments of the present invention, the hidden needle component is provided with a spring arm, the end of the spring arm is provided with a protrusion, and the inner wall of the lower shell is provided with a depth limiting groove that cooperates with the protrusion. When the hidden needle component rotates relative to the lower shell to adjust different needle insertion depths, the spring arm will drive the protrusion to sequentially engage in different depth limiting grooves.

[0017] Advantages and effects of the present invention: This invention provides a reusable autoinjector with an anti-accidental touch mechanism that ensures the injection button movement is not obstructed during reset. This ensures the anti-accidental touch function of the autoinjector while also preventing button wear after multiple resets. Furthermore, a novel stepped needle depth adjustment mechanism is incorporated into the autoinjector with the anti-accidental touch mechanism. This not only effectively solves the core safety and accuracy challenges in reusable scenarios but also produces significant technical effects through the synergistic effect of the two mechanisms. (Includes:) 1. The anti-accidental touch mechanism is proactive and reliable, ensuring stable reset status and resolving wear issues from repeated resets: This invention achieves active anti-accidental touch protection through a sophisticated mechanical linkage logic: During reset, the plunger drive block presses down the stop arm, releasing the restriction on the anti-accidental touch boss; subsequently, the anti-accidental touch spring pushes the anti-accidental touch component forward, allowing its button limiting block to precisely enter the lower part of the injection button. This design forms a physical barrier, rigidly locking the injection button after reset, preventing it from pressing down to contact the injection spring. This mechanism eliminates the possibility of unintended spring release due to any accidental touch, ensuring absolute stability of the energy storage state and avoiding a chain of safety problems such as needle wobbling, liquid leakage, or accidental injury, greatly improving the reliability of the device. Simultaneously, after injection, the stop arm abuts against the anti-accidental touch boss, keeping the button window of the anti-accidental touch component below the stop arm. This ensures the injection button has downward space during reset, preventing collision and compression with the button limiting block, avoiding wear and ensuring multiple resets.

[0018] 2. A new stepped needle depth adjustment mechanism has been added to the automatic injector with anti-accidental contact mechanism, achieving a double leap in safety and accuracy.

[0019] 3. Precise and stable needle depth adjustment with clear feedback, adaptable to diverse injection scenarios: By rotating the hidden needle component, the second stepped limiting platform on it and the first stepped limiting platform on the lower shell form multiple engagement states, realizing multi-level digital adjustment of the needle insertion depth. This adjustment method is structurally stable and has clear settings, completely eliminating reliance on user experience and feel. The engagement between the elastic arm and the depth limiting groove provides clear tactile feedback and a distinct click, ensuring proper adjustment and a secure lock, preventing slippage even during injection. This allows the same device to precisely adapt to the injection depth requirements of different drugs, such as subcutaneous, intramuscular, and intradermal injections, greatly expanding its application range and improving the standardization of injection therapy.

[0020] 4. Functional modules work together efficiently, optimizing user operation processes and experience: This invention is not a simple aggregation of functions, but rather a design that seamlessly integrates accidental touch prevention and depth adjustment into the injection cycle. Depth adjustment and cap removal are performed in one integrated unit using a detachable cap remover; after adjusting the depth, the needle cap can be removed directly, simplifying the process.

[0021] 5. Its compact structure, strong adaptability, and ease of maintenance meet the essential requirement of reusability. The overall design is highly modular. The anti-accidental contact component uses a long cylindrical structure fitted outside the plunger, resulting in a high degree of spatial coupling with the existing injection components. The various components of the needle depth adjustment mechanism are mainly connected through plug-in and snap-fit ​​joints. This design allows the core mechanism of this invention to be easily adapted to existing spring-driven syringe platforms with low modification costs. At the same time, modularity also facilitates disassembly, cleaning, disinfection, and replacement of vulnerable parts (such as springs), perfectly meeting the stringent maintainability requirements of reusable instruments, extending the overall service life of the device, and reducing long-term operating costs.

[0022] 6. Multiple safety redundancy designs comprehensively protect the injection process: In addition to the core features of preventing accidental contact and depth adjustment, this invention integrates multiple auxiliary safety designs: the concealed needle spring design ensures that the needle tip can quickly and automatically conceal itself after injection, preventing needlestick injuries; the sliding limit groove on the needle insertion component, in conjunction with the lower shell latch, rigidly limits the needle insertion stroke through front and rear limit locking components, preventing excessive puncture. These designs together construct a multi-layered safety protection system, significantly reducing various operational risks.

[0023] In summary, this invention, through its groundbreaking integrated design, successfully solves the long-standing technical bottlenecks of reusable syringes in terms of "reset safety," "wear reduction," and "injection accuracy." It provides an innovative injection aid device that is safe, reliable, precisely adjustable, easy to operate, and easy to maintain, which has significant positive implications for promoting the development of reusable injection technology towards higher safety standards and wider application areas. Attached Figure Description

[0024] Figure 1 This is an assembly diagram of the overall structure of the present invention.

[0025] Figure 2 This is an exploded view of the overall structure of the present invention.

[0026] Figure 3 This is a schematic diagram of the overall structure of the injection assembly of the present invention.

[0027] Figure 4 This is a schematic diagram of the injection component before it is reset according to the present invention.

[0028] Figure 5 This is a schematic diagram of the injection component after resetting according to the present invention.

[0029] Figure 6 This is an assembly perspective view of the needle depth adjustment mechanism of the present invention.

[0030] Figure 7 This is a half-sectional schematic diagram of the lower shell of the present invention.

[0031] Figure 8 This is a three-dimensional structural diagram of the hidden needle component of the present invention.

[0032] Figure 9 This is a half-sectional schematic diagram of the hidden needle component of the present invention.

[0033] Figure 10 This is a schematic diagram of the needle insertion component of the present invention.

[0034] Figure 11 This is a schematic diagram of the structure during the preparation stage of the present invention.

[0035] Figure 12 This is a schematic diagram of the structure of the auto-injector after it is pressed down at the injection position during injection, according to the present invention.

[0036] Figure 13 This is a schematic diagram of the structure after the injection of the present invention.

[0037] Figure 14a and Figure 14b This is a three-dimensional structural schematic diagram and a half-sectional view of the hidden needle mating part of the present invention.

[0038] Figure 15a and Figure 15b This is a schematic diagram of the structure in the initial stage of the present invention.

[0039] Figure 16 This is a schematic diagram of the reset and anti-accidental touch activation stages of the present invention.

[0040] Figure 17 This is a schematic diagram of the anti-accidental contact component of the present invention.

[0041] Figure 18a and Figure 18b This is a schematic diagram of the plunger structure of the present invention.

[0042] Figure 19 This is a schematic diagram of the framework of the present invention.

[0043] Figure 20 This is an internal sectional view of the framework of the present invention.

[0044] In the diagram, 100 is the injection assembly; 200 is the needle depth adjustment mechanism; and 300 is the cap remover. 11. Anti-accidental touch spring; 12. Anti-accidental touch component; 121. Button limit block; 122. Anti-accidental touch boss; 13. Injection button; 131. Hook; 132. Button part; 14. Injection spring; 15. Plunger; 151. Stop block; 152. Hanging hole; 153. Sliding groove; 16. Stop spring arm; 17. Viewing window; 18. Frame.

[0045] 21. Lower shell; 22. Hidden needle component; 23. Hidden needle mating component; 24. Needle insertion component; 25. PFS; 211. First stepped limiting platform; 212. Buckle; 213. Depth limiting groove; 221. Second stepped limiting platform; 222. Positioning rib groove; 224. Hidden needle component limiting ring; 225. Elastic arm; 226. Protrusion; 231. Hidden needle component mating groove; 232. First hidden needle spring limiting surface; 234. Opening; 241. Front limiting snap-fit ​​component; 242. Rear limiting snap-fit ​​component; 243. Sliding limiting groove; 244. Second hidden needle spring limiting surface; 26. Hidden needle spring; 27. Upper shell; 28. Soft rubber pad. Detailed Implementation

[0046] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] In this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0048] In this invention, the terms "first" and "second" are used only to distinguish similar components / parts in different positions or with different features, and have no other limiting meaning. In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0049] Example 1 This embodiment provides a reusable autoinjector with a compact overall structure that integrates active anti-accidental contact and precise depth adjustment functions, specifically designed for scenarios requiring safe and precise repeated injections.

[0050] The propulsion gun mainly consists of two functional modules: an injection assembly 100 and a needle depth adjustment mechanism 200 detachably connected to its front end.

[0051] The injection assembly 100 constitutes the main body and drive section of the auto-injector. Its outer casing includes an upper shell 27, on which a viewing window 17 and an injection button panel are provided. The injection button panel has an injection button 13, which includes a button portion and a hook 131. The injection button 13 is plastically deformable; when the button portion 132 is pressed down, the hook 131 can tilt upwards due to plastic deformation. The viewing window 17 allows the user to easily observe the markings below. The internal core consists of an injection drive and an anti-accidental activation mechanism.

[0052] like Figure 3 As shown, the injection drive section includes: a spring post fixed inside the upper shell 27, an injection spring 14 sleeved on the spring post, and a plunger 15 movably sleeved on the front of the injection spring 14. The plunger 15 is a sleeve structure with a hollow interior. A stop block 151 is provided at the bottom of the plunger 15, and a hanging hole 152 is provided at the top, which cooperates with the hook 131 of the injection button 13. Injection in progress and injection complete indicators are provided on the surface of the plunger 15, which can be observed through the viewing window 17. Sliding grooves 153 are provided on the four sides of the plunger 15.

[0053] The anti-accidental touch mechanism is the core safety design of the injection assembly 100, and it is highly integrated with the injection drive part. This mechanism includes an anti-accidental touch component 12, which is a long cylindrical structure partially fitted outside the plunger 15. Its bottom has a slot for the stop block 151 to pass through, ensuring smooth relative movement between the two. The anti-accidental touch component 12 has a button window on the side near the injection button 13. The injection button 13 is mounted on the upper shell 27 via an injection button panel, and its lower part can pass through the upper shell 27 and be pressed down to the button window. At the rear end of the button window, a button limiting block 121 is integrally formed. The button window of the anti-accidental touch component 12 has a deformation space, providing space for the injection button 13 to move downwards; at this time, the button limiting block 121 is located behind this deformation space and will not obstruct the normal downward movement of the injection button 13. An anti-accidental touch boss 122 is provided at the bottom of the anti-accidental touch component 12. The anti-accidental touch spring 11 always abuts against the rear end of the anti-accidental touch component 12, providing it with a forward thrust. A rotatable stop arm 16, driven by a metal torsion spring, is fixed to the inner wall of the upper shell 27. Its free end is naturally raised to abut against the anti-accidental touch boss 122, thereby limiting the forward movement of the anti-accidental touch component 12 under the action of the anti-accidental touch spring 11. In some embodiments of the present invention, the stop arm 16 is made of plastic. To ensure the stability of the anti-accidental touch function, the metal torsion spring and the plastic arm are combined, enabling reuse.

[0054] In the initial state, the button limiting block 121 of the anti-accidental touch component 12 is located below the injection button 13, preventing the injection button 13 from being pressed down and thus preventing accidental touch. During injection, the anti-accidental touch component 12 is pushed backward, and the button window of the anti-accidental touch component 12 reaches the lower part of the injection button 13, allowing the injection button 13 to be pressed down. Pressing down the injection button 13 lifts the hook 131, thereby releasing the plunger 15. The injection spring 14 pushes the plunger 15 forward to achieve needle insertion and injection. After injection, the anti-accidental touch boss 122 of the anti-accidental touch component 12 is abutted by the stop spring arm 16, limiting the forward movement of the anti-accidental touch component 12 under the action of the anti-accidental touch spring 11, so that the button window of the anti-accidental touch component 12 is always located below the injection button 13. After the injection is completed and a reset is required, the plunger 15 is pushed backward. During the reset process, the stop block 151 of the plunger 15 presses down the stop spring arm 16, and the anti-accidental touch component 12 moves forward under the action of the anti-accidental touch spring 11. The button limit block 121 of the anti-accidental touch component 12 moves back to the lower part of the injection button 13 and returns to the initial state.

[0055] The needle depth adjustment mechanism 200 is detachably connected to the front end of the injection assembly 100 via a snap-fit ​​or other means. It internally houses a PFS 25 (pre-filled syringe), which includes a rear push rod. This mechanism mainly includes: The lower shell 21 has a first stepped limiting platform 211 formed on its front inner wall. The front end of this first stepped limiting platform 211 has multiple first stepped contact surfaces located at different axial heights. This multi-step design forms the basis for depth adjustment, and its axial positioning characteristics ensure the stability of the adjusted depth, accurately adapting to different injection needs such as subcutaneous and intramuscular injections. The lower shell 21 also has a buckle 212. A depth limiting groove 213 is provided on the inner wall of the lower shell 21.

[0056] The concealed needle component 22 is located on the inner periphery of the front section of the lower shell 21. The outer surface of the concealed needle component 22 has a second stepped limiting platform 221, on which multiple second stepped contact surfaces corresponding to the first stepped contact surfaces are provided. Depth marks are provided near the second stepped contact surfaces. By rotating the concealed needle component 22, the mating position of the first and second stepped contact surfaces can be changed, thereby changing the axial position of the concealed needle component 22 when moving relative to the lower shell 21, thus achieving needle insertion depth adjustment. The inner wall of the concealed needle component 22 has a positioning rib groove 222, and a concealed needle component limiting ring 224 is also provided on the inner wall of the concealed needle component 22. The hidden needle component 22 is provided with a spring arm 225, and the end of the spring arm 225 is provided with a protrusion 226. The protrusion 226 is in movable cooperation with the depth limiting groove 213 of the lower shell. When the hidden needle component 22 is rotated to switch different depth levels, the spring arm 225 will drive the protrusion 226 to be inserted into different depth limiting grooves 213 in sequence, forming a clear gear feel and sound feedback and mechanical locking point.

[0057] The front end of the concealed needle mating component 23 is connected to the concealed needle limiting ring 224 on the inner circumference of the concealed needle component 22 via the concealed needle mating groove 231, achieving relative rotation under axial limiting. In the initial state and during injection, the rear end of the concealed needle mating component 23 abuts against the anti-accidental touch component 12. When the concealed needle mating component 23 undergoes axial displacement rearward, the anti-accidental touch component 12 will also move rearward, causing the button window of the anti-accidental touch component 12 to reach the lower part of the injection button 13. A first concealed needle spring limiting surface 232 is provided on the inner wall of the middle section of the concealed needle mating component 23. The front end of the concealed needle mating component 23 has an elongated opening 234.

[0058] The needle insert 24 has a second concealed needle spring limiting surface 244 at its rear end. The two ends of the concealed needle spring abut against the first concealed needle spring limiting surface 232 and the second concealed needle spring limiting surface 244, respectively. The outer wall of the needle insert 24 has an elongated protrusion that slides within the elongated opening 234 of the concealed needle mating part 23. The front end of the protrusion has a sliding limiting groove 243, with a front limiting latch 241 and a rear limiting latch 242 at each end. A concealed needle spring 26 is located between the needle insert 24 and the concealed needle mating part 23. The latch 212 of the lower shell 21 extends into this sliding limiting groove 243, and its travel is limited by the front and rear limiting latches. This design provides dual protection: during injection, the needle insert 24 moves forward until the rear limit latch 242 abuts against the latch 212, preventing further forward movement. The plunger then pushes the push rod of the PFS 25 forward to inject the medication. In the initial state, the concealed needle spring 26 biases the needle insert 24 backward, causing the front limit latch 241 to abut against the latch 212, ensuring the needle insert 24 does not continue to detach from the lower housing. Figure 2 As shown, a soft rubber pad 28 is glued to one end of the needle insertion part. Figure 2 (At the right end of the middle), the soft rubber pad 28 acts as a buffer to prevent the flange face of PFS25 from breaking upon impact.

[0059] The cap remover 300 can be detachably inserted into the concealed needle assembly 22. The cap remover 300 has a claw at its front end for holding the pin cap of the PFS 25; its shaft has a positioning rib that engages with the positioning rib groove 222 of the concealed needle assembly 22. This gives the cap remover 300 two functions: first, it acts as a "wrench" to rotate the concealed needle assembly 22 to adjust the depth; second, it holds and pulls forward to remove the pin cap, integrating the operation without the need for additional tools.

[0060] The frame 18 is fixed inside the upper shell 27 in conjunction with the injection button panel. The frame 18 has two guide rail surfaces, and the injection button panel also has two rail surfaces. The four rail surfaces are respectively connected to the four sliding grooves of the plunger 15, so that the plunger 15 can slide on the rail surfaces.

[0061] Working principle and beneficial effects: Preparation stage: such as Figure 11 As shown, insert the cap remover 300 into the hidden needle part 22, and select the desired needle depth by rotating it. The user can clearly feel the elastic arm 225 engaging with different depth limit grooves 213.

[0062] Initial stage: such as Figure 15a and Figure 15bAs shown, after adjustment, use the claw at the front end of the same cap remover 300 to hold the PFS needle cap and pull it forward in a straight line to safely remove the needle cap. Then remove the cap remover 300. At this time, the button limit block 121 of the anti-accidental touch component 12 is below the injection button 13, and the injection button 13 cannot be pressed down.

[0063] During injection: Unlock the anti-accidental activation mechanism: such as Figure 12 As shown, after vertically aligning the front end of the device with the skin at the injection site and pressing down, the hidden needle 22 moves into the lower housing, causing the first stepped contact surface to engage with the second stepped contact surface. Simultaneously, due to the axial displacement of the hidden needle 22, the hidden needle mating component also undergoes axial displacement. Since the rear end of the hidden needle mating component abuts against the anti-accidental contact component 12, the anti-accidental contact component 12 also undergoes axial displacement rearward, bringing the button window of the anti-accidental contact component 12 to the lower part of the injection button 13, allowing the injection button 13 to be pressed down. Injection: As shown Figure 13 As shown, when the injection button 13 is pressed, the hook 131 of the injection button 13 lifts up and leaves the hanging hole 152 of the plunger 15, thereby releasing the plunger 15. The plunger 15 moves forward under the action of the injection spring 14. The plunger 15 pushes the push rod of the PFS, which will push the PFS and the needle insertion member 24 forward, so that the needle of the PFS enters the injection position. When the rear limit latch 242 of the needle insertion member 24 abuts against the lower shell latch 212, the needle insertion member no longer moves forward, and the plunger pushes the push rod of the PFS 25 to start the injection until the injection is completed.

[0064] Reset and accidental touch prevention activation phase: such as Figure 16 After injection, the lower shell and upper shell are separated. A tool is used to push the plunger 15 in the upper shell backward. Preferably, the PFS 25 in the lower shell 21 is removed, and the cap remover 300 is inserted into the hidden needle part 22. The lower shell 21, with the PFS removed, is reversed, and the cap remover 300 is used as a tool to push the plunger backward. When the plunger 15 is pushed to its final position, the stop block 151 at its bottom enters the groove of the anti-accidental touch member 12 and presses down on the stop spring arm 16, causing it to rotate and release the restriction on the anti-accidental touch boss 122. Immediately afterwards, under the push of the anti-accidental touch spring 11, the anti-accidental touch member 12 quickly moves forward, causing its button limiting block 121 to reach the lower part of the injection button 13. The front end of the anti-accidental touch member 12 collides with the frame 18 inside the upper shell and emits a sound, providing audible and mechanical feedback of successful reset. At this time, the injection button 13 is physically blocked and cannot be pressed down, achieving a reliable locking state. The device can be safely stored or carried, completely avoiding the risk of accidental activation. In addition, the rearward movement of the plunger 15 causes its hanging hole 152 to engage with the hook 131 at the front end of the injection button 13, thereby achieving the reset of the plunger 15.

[0065] This embodiment seamlessly integrates depth adjustment, safe injection, automatic anti-accidental touch locking, and reset confirmation through the aforementioned ingenious mechanical linkage, achieving a significant improvement in ease of operation, injection accuracy, and safety of use on a reusable device.

[0066] Example 2 Based on Embodiment 1, this embodiment further provides some preferred variations to demonstrate the flexibility and universality of the invention.

[0067] In this embodiment, the first stepped contact surface of the first stepped limiting platform 211 and the second stepped contact surface of the second stepped limiting platform 221 may be provided with fine anti-slip textures (such as serrated or mesh patterns) that cooperate with each other. This can effectively increase the static friction between the mating surfaces, further improve the long-term stability of the needle depth setting lock, and even after frequent adjustment and use, it can still effectively prevent the setting from loosening due to minor wear, ensuring the precise consistency of the injection depth each time.

[0068] In this embodiment, the number and distribution of the depth limiting grooves 213 can be optimized according to the most common injection depth range in clinical practice. For example, four equally spaced grooves can be set to correspond to four commonly used depth levels; or, in order to meet the precise injection range of certain specific drugs, a non-equally spaced design can be adopted, with denser grooves set in key depth ranges (such as the 2-4mm range for subcutaneous injection), to achieve more precise depth adjustment, thereby expanding the applicability of the device in the field of specialized treatment.

[0069] In this embodiment, the fixed end of the stop arm 16 can be designed to be finely adjusted, for example, by adding an adjusting shim at the fixing screw, thereby precisely calibrating the natural contact pressure between its free end and the anti-accidental contact protrusion 122. This ensures that the anti-accidental contact mechanism can maintain optimal trigger sensitivity and locking reliability in different production batches or after long-term use, improving the product's quality control level and long-term stability.

[0070] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the claims.

Claims

1. A reusable auto-injector, characterized in that, The device includes an injection assembly (100), comprising an upper shell (27), an injection button (13), an injection spring (14), a plunger (15), and an anti-accidental touch mechanism. The anti-accidental touch mechanism includes an anti-accidental touch component (12), one side of which has a button window, and a button limiting block (121) at the rear end of the button window. The other side of the anti-accidental touch component (12) has an anti-accidental touch boss (122). The rear anti-accidental touch spring (11) provides a biasing force to hold the button limiting block (121) under the injection button (13); a stop spring arm (16); the button limiting block (121) is located under the injection button (13) to prevent accidental touch of the injection button (13) when not injecting; the plunger (15) is movably sleeved on the front of the injection spring (14); during injection, the anti-accidental touch component (12) is pushed backward, the button limiting block (121) is pushed away from the lower part of the injection button (13), and the button window reaches the lower part of the injection button (13); after injection, the stop spring arm (16) is released from the lower part of the injection button (13). The spring arm (16) abuts against the anti-misoperation boss (122), and the button window remains at the bottom of the injection button (13). After the injection is completed, when the plunger (15) is pushed back to reset, the plunger (15) presses down the stop spring arm (16), the stop spring arm (16) disengages from the anti-misoperation boss (122), and the button limiting block (121) returns to the lower part of the injection button (13) under the action of the anti-misoperation spring (11). The needle depth adjustment mechanism (200) includes a lower shell (21) and a hidden needle component (22). The hidden needle component (22) rotates relative to the lower shell (21) to adjust different needle depths.

2. The reusable auto-injector of claim 1, wherein, The inner wall of the front end of the lower shell (21) is provided with a first stepped limiting platform (211), and the front end of the first stepped limiting platform (211) has multiple first stepped contact surfaces located at different heights in the axial direction; the surface of the hidden needle (22) is provided with a second stepped limiting platform (221), and the second stepped limiting platform (221) is provided with multiple second stepped contact surfaces that cooperate with the first stepped contact surfaces. During injection, the hidden needle (22) moves inward relative to the lower shell (21), and the first stepped contact surface engages with the second stepped contact surface.

3. A reusable auto-injector according to claim 2, wherein Also includes: A concealed needle fitting (23) whose front end is connected to the inner periphery of the concealed needle (22), the concealed needle fitting (23) and the concealed needle (22) being fixed in the axial direction; a concealed needle spring that provides a spring force to bias the concealed needle fitting (23) forward; a needle inlet (24) that can slide relative to the lower shell (21); and a pfs (25) that is detachably disposed in the needle inlet (24).

4. The reusable auto-injector of claim 3, wherein, The needle insertion component (24) is provided with a sliding limiting groove (243). The two ends of the sliding limiting groove (243) are respectively provided with a front limiting snap-fit ​​component (241) and a rear limiting snap-fit ​​component (242). The lower shell (21) is provided with a buckle (212). The buckle (212) cooperates with the front limiting snap-fit ​​component (241) and the rear limiting snap-fit ​​component (242) to limit the travel of the needle insertion component (24) relative to the lower shell (21).

5. The reusable auto-injector of claim 4, wherein, The inner wall of the hidden needle fitting (23) is provided with a first hidden needle spring limiting surface (232), and the rear end of the needle insertion part (24) is provided with a second hidden needle spring limiting surface (244) opposite to the first hidden needle spring limiting surface (232). The two ends of the hidden needle spring abut against the first hidden needle spring limiting surface (232) and the second hidden needle spring limiting surface (244) respectively.

6. The reusable autoinjector according to claim 2, characterized in that, The injection button (13) has a hook (131) at its front end, and the plunger (15) has a hanging hole (152) that cooperates with the hook (131).

7. The reusable autoinjector according to claim 2, characterized in that... It also includes a frame. After the injection is completed, when the plunger (15) is pushed back to reset, the plunger (15) presses down on the stop spring arm (16), the stop spring arm (16) disengages from the anti-accidental contact boss (122), and the anti-accidental contact component (12) moves forward under the action of the anti-accidental contact spring (11) and collides with the frame to make a sound.

8. The reusable autoinjector according to claim 7, characterized in that, The plunger (15) is provided with a stop (151). After the injection is completed, when the plunger (15) is pushed back to reset, the stop (151) presses down the stop spring arm (16), and the stop spring arm (16) disengages from the anti-accidental contact boss (122). The anti-accidental contact component (12) is a long cylindrical structure that is partially sleeved on the outside of the plunger (15). The anti-accidental contact component (12) is provided with a strip groove for the stop (151) to pass through.

9. The reusable autoinjector according to claim 2, characterized in that, The upper shell (27) of the injection assembly (100) is provided with a window (17), and the plunger (15) is marked with an injection in progress and an injection completion mark, which is displayed in the window (17).

10. The reusable autoinjector according to claim 3, characterized in that, The hidden needle (22) is detachably connected to a cap remover (300) on its inner circumference. The hidden needle (22) is rotated by rotating the cap remover (300). The pfs (25) is provided with a needle cap, and the front end of the cap remover (300) is provided with a claw that engages with the needle cap.

11. The reusable autoinjector according to claim 3, characterized in that, The front section of the hidden needle fitting (23) is provided with a hidden needle fitting groove (231), and the inner surface of the hidden needle (22) is provided with a hidden needle limiting ring that mates with the hidden needle fitting groove (231).

12. The reusable autoinjector according to claim 2, characterized in that, The hidden needle component (22) is provided with a spring arm (225), and the end of the spring arm (225) is provided with a protrusion (226). The inner wall of the lower shell (21) is provided with a depth limiting groove (213) that cooperates with the protrusion (226). When the hidden needle component (22) rotates relative to the lower shell (21) to adjust different needle insertion depths, the spring arm (225) will drive the protrusion (226) to be inserted into different depth limiting grooves (213) in sequence.

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