First-aid injection pen

Abstract

The invention relates to the technical field of medical instrument manufacturing, in particular to a first-aid injection pen which comprises an excitation force locking mechanism, a PFS assembly, a driving assembly, a starting shell, an upper shell and a lower shell. The excitation force locking mechanism comprises an excitation rod, an inner main body and an outer main body in sequence from inside to outside, and is respectively provided with an upper radial extension limiting structure, a radial springback blocking structure and an avoiding notch. The driving assembly comprises an excitation spring, a spring containing piece and an auxiliary spring. In the initial state, the radial springback blocking structure and the avoiding notch are staggered and are surrounded and restrained by the outer body, the excitation rod is limited, the excitation spring is compressed, the auxiliary spring is naturally or slightly compressed, and the injection needle is hidden. In the excited state, the starting shell moves upwards to push the outer main body, the avoiding notch is right opposite to the radial springback blocking structure, the excitation rod is unlocked, injection is driven by the excitation spring, and the auxiliary spring synchronously stores energy. After the injection operation is finished, the auxiliary spring releases energy to push the outer main body and the starting shell to move downwards, and the injection needle is hidden.

Description

Technical Field

[0001] The present invention relates to the technical field of medical device manufacturing, and in particular to an emergency injection pen. Background Art

[0002] In the field of medical first aid, the safety locking and needle hiding functions of portable injection pens are crucial.

[0003] Existing emergency injection pens have significant defects in the safety locking mechanism, specifically manifested as follows: Traditional designs mostly adopt single-point clamping or interference fit, such as the simple contact structure between a boss and a housing. Under transportation vibration or external force impact, axial movement is likely to occur, resulting in accidental unlocking of the firing rod, causing premature drug release or dose deviation. More notably, the unlocking force of this type of locking structure is often difficult to precisely control, and it is extremely easy to be accidentally fired due to daily touch, or it may cause difficulty in firing during normal use, seriously affecting the first aid efficiency.

[0004] The technical bottlenecks of the needle hiding function are reflected in insufficient structural reliability and automation. Regarding the current industry situation, the manual hiding design requires the user to perform additional operations such as pressing after injection. However, in an emergency scenario where every second counts, the operator is likely to omit this step due to nervousness or panic, resulting in the needle remaining exposed, greatly increasing the risk of stabbing for medical staff or patients. For some products with automatic hiding functions, most rely on a single spring drive. When the auxiliary spring is fatigued or the fit tolerance between the starting shell and the lower housing exceeds the tolerance, it is difficult to precisely control the needle hiding stroke, and the needle may be exposed during actual use, which obviously does not meet the safety standards of medical devices. In addition, since this type of automatic hiding structure lacks a linkage design with the firing process, it often requires an additional power source, which not only increases the complexity of the structure but also increases the probability of failure. Therefore, it is urgent for technical personnel to solve the above problems. Summary of the Invention

[0005] The present invention provides an emergency injection pen, which aims to solve the technical problems of existing emergency injection pens in aspects such as firing safety locking and needle hiding through the collaborative design of multiple components.

[0006] The present invention relates to an emergency injection pen, including a firing force locking mechanism, a PFS assembly, a driving assembly, a starting shell, an upper housing, and a lower housing that cooperate to achieve the functions of initial locking, firing injection, and needle hiding during the injection process;

[0007] The PFS assembly is received by the starting shell and includes a syringe barrel, a piston, and an injection needle. The starting shell is sleeved in the lower housing;

[0008] The actuating force locking mechanism includes an actuating rod, an inner main body, and an outer main body that are sleeved in sequence from the inside out; an upper radially extending limiting structure is formed on the actuating rod, a radially resilient blocking structure is formed on the inner main body, and an avoidance notch is formed on the outer main body;

[0009] The driving assembly includes an actuating spring and a spring receiving member sleeved around the actuating rod, and an auxiliary spring compressed between the upper housing and the outer main body; the actuating spring is received by the spring receiving member and axially pressed, and is inserted into the accommodating cavity of the actuating rod;

[0010] In the initial state, the radially resilient blocking structure is misaligned with the avoidance notch, and it is surrounded and constrained by the outer main body. The axial displacement of the actuating rod is limited, the actuating spring is compressed, the auxiliary spring is in a natural length or slightly compressed state, the injection needle is hidden in the starting shell, and the starting shell and the lower shell maintain the initial assembly position;

[0011] In the actuated state, the starting shell is pushed up by the human body, pushing the outer main body to move up. The avoidance notch is aligned with the radially resilient blocking structure. The radially resilient blocking structure expands under the radial component force of the upper radially extending limiting structure to unlock the actuating rod. The actuating spring releases its potential energy to push the actuating rod down to drive the piston to complete the injection. At the same time, the auxiliary spring is compressed and stores energy due to the relative movement between the upper housing and the outer main body;

[0012] In the state after the injection is completed, the starting shell is separated from the human body. The auxiliary spring releases its energy to push the outer main body down, synchronously driving the starting shell to move down in the lower shell, so that the needle is hidden in the starting shell again.

[0013] As a further improvement of the technical solution disclosed in the present invention, the upper radially extending limiting structure includes n built-in limiting protrusions evenly distributed along the circumferential side of the actuating rod; the radially resilient blocking structure includes n radially resilient arms formed by slitting the circumferential side of the inner main body. The number of avoidance notches is also n. An external limiting protrusion is provided at the free end of the radially resilient arm to be adapted to the built-in limiting protrusion, and n≥1.

[0014] As a further improvement of the technical solution disclosed in the present invention, the built-in limiting protrusion is subjected to bevel cutting to form an inner upper sliding guiding surface and an inner lower sliding guiding surface; the external limiting protrusion is subjected to bevel cutting to form an external upper sliding guiding surface adapted to the inner lower sliding guiding surface and an external lower sliding guiding surface adapted to the inner upper sliding guiding surface.

[0015] As a further improvement of the technical solution disclosed in the present invention, the elastic modulus of the radially resilient arm is 1.8 - 2.5 GPa, the unlocking force is 8 - 12 N, it has a gradually changing thickness structure, the root thickness is 1 - 1.5 mm, the free end thickness is 0.5 - 0.8 mm, and the length L satisfies L=(D·tanα) / 2 + 2t, where D is the outer diameter of the actuating rod, α is the horizontal angle of the inner lower sliding guiding surface, and t is the radial thickness of the built-in limiting protrusion.

[0016] As a further improvement of the technical solution disclosed in the present invention, the trigger rod is also formed with a lower radial extension limit structure. The lower radial extension limit structure includes m arc-shaped limit bodies, m ≥ 2, and is evenly distributed around the central axis of the trigger rod; the tail of the syringe barrel is formed with an annular stop edge that contacts and cooperates with the arc-shaped limit body; the perpendicularity tolerance between the annular stop edge and the central axis of the syringe barrel is ≤ 0.05mm.

[0017] As a further improvement of the technical solution disclosed in the present invention, the axial distance L1 between the upper radially outward limiting structure and the lower radially outward limiting structure, and the axial distance L2 from the initial position of the piston to the bottom of the syringe barrel, satisfy L1=(0.95-1.05)L2; when the arc-shaped limiting body contacts the annular stop edge during the downward movement of the excitation rod, the piston just reaches the bottom of the syringe barrel.

[0018] As a further improvement of the technical solution disclosed in the present invention, the spring storage component includes a main body, a left-placed elastic arm, a right-placed elastic arm and a middle auxiliary positioning column; the left-placed elastic arm and the right-placed elastic arm are symmetrically distributed along the central axis of the middle auxiliary positioning column; the middle auxiliary positioning column is inserted into the excitation spring to control the radial offset of its upper end portion.

[0019] As a further improvement of the technical solution disclosed in the present invention, the inner side wall of the inner main body is formed with a left-placed limit groove adapted to the left-placed elastic arm and a right-placed limit groove adapted to the right elastic arm; the depth of the left-placed limit groove is 0.5~1.2mm, and the groove width is 0.1~0.2mm larger than the thickness of the left elastic arm; the depth of the right-placed limit groove is 0.5~1.2mm, and the groove width is 0.1~0.2mm larger than the thickness of the right elastic arm.

[0020] As a further improvement of the technical solution disclosed in the present invention, an upper radial outward anti-slip structure and a lower radial rebound damping structure are axially arranged on the starting shell; an upper resistance step and a lower resistance step are arranged on the inner wall of the lower shell; in the initial state, the upper radial outward anti-slip structure touches the upper resistance step, and the lower radial rebound damping structure and the lower resistance step maintain an axial gap of 0.1 to 0.3 mm; when the starting shell is moved upward by the top touch, the lower radial rebound damping structure contracts radially and passes over the lower resistance step; after the injection is completed, the lower radial rebound damping structure expands radially and touches the upper resistance step, and the maximum downward movement stroke of the starting shell is limited.

[0021] As a further improvement of the technical solution disclosed in the present invention, the upper radial outward anti-slip structure includes q upper radial outward anti-slip protrusions, and the lower radial rebound damping structure includes q radial rebound damping hook arms, q≥1; the radial rebound damping hook arms are formed by cutting the circumferential side of the starting shell, and when excited, they are radially contracted by the reaction force of the lower resistance step to cross the lower resistance step, and after injection is completed, they radially expand and touch the upper resistance step.

[0022] In practical applications, the emergency injection pen disclosed in the present invention can achieve at least the following beneficial technical effects, specifically:

[0023] 1) In terms of the safety locking mechanism, this solution achieves multi-dimensional constraints through the spatial coordination of the geometric structures of the trigger rod, inner body, and outer body. In the initial state, the outer body embraces and constrains the radial rebound blocking structure, and forms a mechanical interlock with the upper radial extension limit structure, thereby effectively resisting transportation vibration or external force impact, and avoiding the premature release of drugs caused by axial movement of the trigger rod. When triggered, the outer body moves upward to make the avoidance gap face the radial rebound blocking structure, and the radial force is used to drive the radial rebound blocking structure to expand and unlock. In this way, not only does it prevent the occurrence of daily touch-induced misactivation, but it also ensures that the trigger rod can respond quickly when performing emergency operations, solving the problem of difficult-to-control unlocking force in traditional design structures;

[0024] 2) For the injection needle hiding function, this solution uses the dual power sources of the excitation spring and the auxiliary spring. During injection, the auxiliary spring is compressed to store energy, and after injection, the energy is released to push the outer body linkage starter shell downward, so that the injection needle is hidden in the starter shell again; and the injection needle hiding action is organically integrated with the injection force excitation process, and no additional power source is required throughout the action, which simplifies the design structure of the emergency injection pen while improving its reliability;

[0025] 3) From the perspective of overall structural design, the excitation force locking mechanism, drive assembly and PFS assembly are linked to complete locking, injection force excitation and injection needle hiding in sequence during the injection process. In addition, the dual-power design of the excitation spring and auxiliary spring not only provides stable injection power, but also realizes self-hiding of the injection needle, thereby improving the application stability and safety of the first aid injection pen, and providing an efficient and reliable portable solution for first aid scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 It is a three-dimensional schematic diagram of the first aid injection pen disclosed by the present invention.

[0028] Figure 2 yes Figure 1 Side view of.

[0029] Figure 3 yes Figure 2A-A sectional view.

[0030] Figure 4 is Figure 3 Partial enlarged view I of...

[0031] Figure 5 is Figure 3 Partial enlarged view II of...

[0032] Figure 6 is Figure 3 Partial enlarged view III of...

[0033] Figure 7 is Figure 4 Partial enlarged view IV of...

[0034] Figure 8 is Figure 4 Partial enlarged view V of...

[0035] Figure 9 is Figure 5 Partial enlarged view VI of...

[0036] Figure 10 is a three-dimensional schematic diagram of the firing rod in the first-aid injection pen disclosed by the present invention.

[0037] Figure 11 is a three-dimensional schematic diagram of the inner main body in the first-aid injection pen disclosed by the present invention.

[0038] Figure 12 is Figure 11 Side view of...

[0039] Figure 13 is Figure 12 B-B sectional view of...

[0040] Figure 14 is a three-dimensional schematic diagram of the outer main body in the first-aid injection pen disclosed by the present invention.

[0041] Figure 15 is a three-dimensional schematic diagram of the spring storage member in the first-aid injection pen disclosed by the present invention.

[0042] Figure 16 is a three-dimensional schematic diagram of the activation shell in the first-aid injection pen disclosed by the present invention.

[0043] Figure 17 is a three-dimensional schematic diagram of the lower housing in the first-aid injection pen disclosed by the present invention.

[0044] Figure 18 is Figure 17 Side view of...

[0045] Figure 19 is Figure 18 C-C sectional view of...

[0046] Figure 20 It is a schematic diagram of the action process of the excitation force locking mechanism in the first-aid injection pen disclosed by the present invention (in sequence: initial state, critical trigger state of the excitation rod, and completed trigger state).

[0047] 1 - Excitation force locking mechanism; 11 - Excitation rod; 111 - Upper radially extending limiting structure; 1111 - Built-in limiting protrusion; 11111 - Built-in upper sliding guiding surface; 11112 - Built-in lower sliding guiding surface; 112 - Accommodating cavity; 113 - Lower radially extending limiting structure; 1131 - Arc-shaped limiting body; 12 - Inner main body; 121 - Radial spring-back blocking structure; 1211 - Radial spring-back arm; 12111 - External limiting protrusion; 121111 - External upper sliding guiding surface; 121112 - External lower sliding guiding surface; 122 - Left limiting groove; 123 - Right limiting groove; 124 - Left blocking and leaning extension body; 125 - Right blocking and leaning extension body; 13 - Outer main body; 131 - Avoidance notch; 2 - PFS assembly; 21 - Syringe barrel; 211 - Annular stop edge; 22 - Piston; 23 - Injection needle; 3 - Driving assembly; 31 - Excitation spring; 32 - Spring storage part; 321 - Body; 322 - Left elastic arm; 3221 - Left limiting extension body; 323 - Right elastic arm; 3231 - Right limiting extension body; 324 - Middle auxiliary positioning column; 33 - Auxiliary spring; 4 - Starting shell; 41 - Upper radially extending anti-detachment structure; 411 - Upper radially extending anti-detachment protrusion; 42 - Lower radial spring-back damping structure; 421 - Radial spring-back damping hook arm; 5 - Upper outer shell; 6 - Lower outer shell; 61 - Upper blocking step; 62 - Lower blocking step; 7 - Safety locking soft cap. Detailed implementation manners

[0048] In the description of the present invention, it should be understood that the positional or positional relationships indicated by the terms "left", "right", "front", "rear", "upper", "lower", etc. are based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific position, be constructed and operated in a specific position, and thus should not be construed as a limitation to the present invention.

[0049] A first-aid injection pen is a portable automatic injection device designed specifically for emergency treatment scenarios and is used to quickly and accurately inject first-aid drugs (such as adrenaline, insulin, etc.) into a patient's body. Its core function is to complete puncture and liquid medicine pushing within a short time.

[0050] The following will further elaborate on the first-aid injection pen disclosed by the present invention in combination with specific embodiments, as Figures 1 - 6As shown in the figure, it is mainly composed of an excitation force locking mechanism 1, a PFS component 2, a driving component 3, a starting shell 4, an upper shell 5, a lower shell 6 and a safety locking soft cap 7, which work together to achieve the initial locking, excitation injection and needle concealment functions. The safety locking soft cap 7 is pre-assembled at the lower end of the lower shell 6 to tightly cover the PFS component 2 to form a physical isolation barrier, effectively preventing the PFS component 2 from being contaminated or accidentally touched when not in use. When the injection operation is required, the user only needs to remove the safety locking soft cap 7 to release the protection state.

[0051] The starter housing 4 is sleeved in the lower housing 6 . The PFS assembly 2 is received by the starter housing 4 , and includes a syringe barrel 21 , a piston 22 and an injection needle 23 .

[0052] The excitation force locking mechanism 1 includes an excitation rod 11, an inner body 12 and an outer body 13 which are sequentially mounted from the inside to the outside. The upper shell 5 is in the form of an outer layer wrapping, and is coaxially mounted with the outer body 13, the inner body 12 and other components along the axial direction, and its inner wall is tightly matched with the outer body 13. Under the synergistic effect of the inner body 12 and the outer body 13, the axial displacement freedom of the excitation rod 11 is limited.

[0053] The excitation rod 11 is formed with an upper radial extension limit structure 111 and a receiving cavity 112. The upper radial extension limit structure 111 is composed of two oppositely disposed internal limit protrusions 1111 (such as Figure 10 ).

[0054] A radial rebound blocking structure 121 is formed on the inner body 12. In order to adapt to the internal limiting protrusion 1111, the radial rebound blocking structure 121 is composed of two radial rebound arms 1211 disposed opposite to each other. The radial rebound arm 1211 is formed by cutting and removing material from the circumferential outer wall of the inner body 12, and an external limiting protrusion 12111 (such as Figures 11 - 13 ).

[0055] Near the bottom end, the outer body 13 is formed with two oppositely disposed avoidance notches 131 to match the radial rebound blocking structure 121 (eg Figure 14 ).

[0056] The driving assembly 3 includes an excitation spring 31 and a spring receiving member 32 sleeved on the periphery of the excitation rod 11, and an auxiliary spring 33 compressed between the upper housing 5 and the outer body 13. The excitation spring 31 is received and axially pressed by the spring receiving member 32, and is inserted into the accommodating cavity 112.

[0057] Figure 20 The schematic diagram of the action flow of the excitation force locking mechanism is shown, and it can be clearly seen that:

[0058] Initial locking state: The safety locking soft cap 7 covers the lower end of the lower housing 6, physically isolating the PFS assembly 2 (including the injection needle 23) to avoid contamination and accidental contact. The radially resilient arm 1211 is misaligned with the avoidance notch 131, and the outer body 13 circumferentially restricts the radially resilient arm 1211, causing the built-in limit protrusion 1111 and the external limit protrusion 12111 to be interlocked, restricting the axial movement freedom of the firing rod 11; the firing spring 31 is compressed between the spring housing 32 and the accommodating cavity 112, and the auxiliary spring 33 is compressed and stores energy under the action of the upper housing 5 and the outer body 13, and the whole is in a safe state waiting to be triggered.

[0059] Firing injection process: After removing the safety locking soft cap 7, press the emergency injection pen against the injection site. The human body's pushing force causes the activation shell 4 to move upward along the lower housing 6, and then pushes the outer body 13 upward, aligning the avoidance notch 131 with the radially resilient arm 1211. At this time, the outer body 13 releases the circumferential restraint on the radially resilient arm 1211. The firing rod 11 has a downward movement tendency under the action of the firing spring 31. The built-in limit protrusion 1111 contacts the external limit protrusion 12111, and through the inclined plane geometric design, the axial force is converted into a radial component force, driving each radially resilient arm 1211 to expand outward; after the radially resilient arms 1211 expand, each built-in limit protrusion 1111 can smoothly cross the corresponding external limit protrusion 12111. At this time, the outer body 13 remains in the upward movement state, and each radially resilient arm 1211 radially contracts due to elastic reset, but the built-in limit protrusion 1111 has left the blocking area, and the firing rod 11 obtains the axial displacement freedom to complete the unlocking. The firing spring 31 continues to release potential energy to drive the firing rod 11 downward, pushing the piston 22, so that the liquid medicine in the syringe barrel 21 is accurately injected into the human body through the injection needle 23; at the same time, the upward movement of the outer body 13 further compresses the auxiliary spring 33 to store energy.

[0060] Needle retraction after injection: After the injection is completed, the activation shell 4 loses the pushing force. The auxiliary spring 33 releases energy to push the outer body 13 downward, driving the activation shell 4 to move downward synchronously until the injection needle 23 is completely retracted into the activation shell 4 to avoid the risk of needle exposure causing stabbing. After the firing rod 11 moves downward after the injection is completed, the outer body 13 loses the pushing force and falls back. The radially resilient arms 1211 and the avoidance notch 131 are misaligned again, and it is radially circumferentially restrained by the outer body 13 again, restricting the radial expansion freedom of each radially resilient arm 1211.

[0061] In terms of the safety locking mechanism, this solution realizes multi-dimensional constraints through the spatial coordination of the geometric structures of the excitation rod 11, the inner body 12, and the outer body 13. In the initial state, the outer body 13 embraces the constrained radial rebound blocking structure 121, and forms a mechanical interlock with the upper radial extension limit structure 111, that is, the outer body 13 embraces the radial rebound arm 1211 to form a physical constraint on its radial expansion, and at the same time utilizes the mechanical interlocking mechanism of the built-in limit protrusion 1111 and the external limit protrusion 12111 to lock the axial displacement freedom of the excitation rod 11, and rigid locking can be achieved only through the geometric coordination of the outer body 13 and the inner body 12, thereby effectively resisting transportation vibration or external force impact, and avoiding the occurrence of premature drug release caused by axial movement of the excitation rod 11. When triggered, the outer body 13 moves upward to make the avoidance notch 131 face the radial rebound blocking structure 121, and the radial rebound blocking structure 121 is driven to expand and unlock through the radial force component, that is, each radial rebound arm 1211 expands itself due to the radial force component from the corresponding built-in limiting protrusion 1111, and the active decoupling of radial constraints is achieved through the structural geometric design. In this way, not only the occurrence of daily touch-induced mis-activation is eliminated, but also the trigger rod 11 is ensured to respond quickly when performing emergency operations, solving the problem of difficult control of unlocking force in traditional design structures;

[0062] Furthermore, for the hidden function of the injection needle 23, this solution uses the dual power sources of the excitation spring 31 and the auxiliary spring 33. During injection, the auxiliary spring 33 is compressed to store energy, and after injection, the energy is released to push the outer body 13 to move the linkage start shell 4 downward, so that the injection needle 23 is hidden again in the start shell 4; and the hiding action of the injection needle 23 is organically integrated with the injection force excitation process, and no additional power source is required throughout the action, which simplifies the design structure of the emergency injection pen while improving its reliability;

[0063] From the perspective of the overall structural design, the excitation force locking mechanism 1, the driving component 3 and the PFS component linkage 2 successively complete the locking of the excitation rod 11, the excitation of the excitation spring 31 and the hiding of the injection needle 23 during the injection process. In addition, the dual-power design of the excitation spring 31 and the auxiliary spring 33 not only provides stable injection power, but also realizes the self-hiding of the injection needle 23, thereby improving the application stability and safety of the first aid injection pen, and providing an efficient and reliable portable solution for first aid scenarios.

[0064] Here, it is particularly important to note that when the built-in limit protrusion 1111 passes over the external limit protrusion 12111 and after the emergency injection pen completes the injection, each radial rebound arm 1211 is misaligned with the avoidance notch 131 again, and it can be re-encircled and constrained by the outer body 13, thereby preventing it from expanding again. In this way, the physical irreversible locking design goal after a single trigger is achieved, and the secondary trigger path is directly blocked by the mechanical structure, solving the risk of repeated injection caused by misoperation in traditional designs.

[0065] As Figures 10 - 13 , Figure 7 shown in r , the built-in limit protrusion 1111 undergoes a chamfering process, and an inner upper sliding guiding surface 11111 is formed on its top wall, and an inner lower sliding guiding surface 11112 is formed on its bottom wall. The external limit protrusion 12111 undergoes a chamfering process, and an external upper sliding guiding surface 111111 adapted to the inner lower sliding guiding surface 11112 is formed on its top wall, and an external lower sliding guiding surface 121112 adapted to the inner upper sliding guiding surface 11111 is formed on its bottom wall. In this way, on the one hand, the angular design of the inner upper sliding guiding surface 11111 and the external lower sliding guiding surface 121112 efficiently decomposes the axial force into a radial expansion force F r and a tangential sliding force F, which can generate sufficient radial expansion force under a small axial thrust to reduce the energy threshold required for unlocking; on the other hand, when unlocking, the inner lower sliding guiding surface 11112 abuts against the external upper sliding guiding surface 111111, guiding the radial rebound arm 1211 to expand gently in the radial direction; subsequently, the inner upper sliding guiding surface 11111 cooperates with the external lower sliding guiding surface 121112 to ensure that there is no jamming during the passing-over process.

[0066] According to long-term manufacturing production experience, the elastic modulus of the radial rebound arm 1211 is also controlled within 1.8 - 2.5 GPa, which is adapted to medical-grade plastics such as polycarbonate, polyamide, polyoxymethylene, and polypropylene. While ensuring that the material has good elastic recovery ability, the brittle risk of high-modulus materials is avoided.

[0067] Furthermore, the unlocking force of the radial rebound arm 1211 should be maintained at 8 - 12 N. In this way, it can not only ensure that the emergency injection pen can be triggered quickly but also prevent misoperation caused by accidental situations such as collisions during daily carrying.

[0068] As an optimized design structure, the radial rebound arm 1211 also has a gradually changing thickness structure. Its root thickness is 1 - 1.5 mm, and the free end thickness is 0.5 - 0.8 mm, and its length L satisfies the formula:

[0069] L = (D * tanα) / 2 + 2t;

[0070] Wherein, D is the outer diameter of the trigger rod 11, α is the horizontal angle of the built-in lower sliding guide surface 11112, and t is the radial thickness of the built-in limiting protrusion 1111. The numerical value of (D*tanα) ensures that when the rebound arm 1211 expands, the displacement of the free end allows the built-in limiting protrusion 1111 to smoothly pass over the external limiting protrusion 12111 opposite to it; the numerical value of +2t is a reserved safety margin to compensate for the Poisson effect of the material and the manufacturing tolerance, ensuring a smooth and stable unlocking process.

[0071] Furthermore, if Figure 10 As shown in FIG. 1 , the trigger rod 11 is also formed with a lower radial extension limit structure 113. The lower radial extension limit structure 113 includes two arc-shaped limit bodies 1131 disposed opposite to each other. The tail of the syringe barrel 21 is formed with an annular stop edge 211 (as shown in FIG. 1 ) that contacts and cooperates with the arc-shaped limit bodies 1131. Figure 4 ). In actual application, in the initial state, the piston 22 is located at the initial position of the syringe barrel 21, and the liquid medicine is pre-installed in the syringe barrel 21. When the emergency injection pen is triggered, the trigger rod 11 moves downward rapidly along the axial direction due to the axial thrust, and at the same time, the arc-shaped limiter 1131 used to limit the final stroke moves synchronously; injection stage: during the downward movement of the trigger rod 11, the piston 22 is pushed to compress the liquid medicine in the syringe; as the piston 22 continues to slide, the liquid medicine is ejected through the injection needle 23 until the arc-shaped limiter 1131 conflicts with the annular stop edge 211, and the quantitative injection is completed.

[0072] By adopting the above technical solution, on the one hand, the interval-arranged built-in limiting protrusions 1111 and arc-shaped limiting bodies 1131 cooperate with the inner body 12, the outer body 13 and the syringe barrel 21 to form a precise injection stroke control mechanism. The built-in limiting protrusions 1111 are locked by the external limiting protrusions 12111 to ensure the stability of the initial state; after being triggered, the excitation rod 11 moves downward, and when the arc-shaped limiting body 1131 conflicts with the annular stop edge 211, the excitation rod 11 stops moving, that is, the axial movement distance of the excitation rod 11 is precisely limited, and the displacement of the piston 22 is directly related to the downward movement distance of the excitation rod 11, thereby accurately controlling the movement stroke of the piston 22 in the syringe barrel 21, ensuring that the volume of the liquid medicine discharged during each injection is consistent, and achieving precise quantitative determination.

[0073] like Figure 10 As shown in , the excitation rod 11 is preferably formed by an integrated injection molding process, and the built-in limiting protrusion 1111 and the arc-shaped limiting body 1131 are simultaneously molded in the same injection molding process, thereby facilitating ensuring the position accuracy and structural integrity of the two.

[0074] As described above, the quantitative injection mechanism limits the stroke of the piston 22 by the arc-shaped limiting body 1131 abutting against the annular stop edge 211, thereby controlling the injection dose. If the perpendicularity of the annular stop edge 211 is insufficient, the excitation rod 11 is bound to tilt when performing the downward movement, which will in turn cause a deviation in the stroke of the piston 22, resulting in a mismatch between the actual injection dose and the preset value. In view of this, as a further optimization of the above technical solution, the perpendicularity tolerance between the annular stop edge 211 and the axis of the syringe barrel 21 does not exceed 0.05 mm, so as to ensure that each time the excitation rod 11 moves downward to the limiting position, the moving distance of the piston 22 is precisely the same, ensuring that the volume of the liquid medicine injected each time is constant and achieving high-precision quantitative injection.

[0075] As Figure 3 shown in the figure, the axial distance between the built-in limiting protrusion 1111 and the arc-shaped limiting body 1131 is L1, and the axial distance L2 from the initial position of the piston 22 to the bottom of the syringe barrel 21. The movement stroke of the excitation rod 11 is determined by L1, and L2 directly affects the volume of the liquid medicine discharged. Therefore, by limiting the proportional relationship between L1 and L2, for example: the relationship between L1 and L2 satisfies the formula: L1 = (0.95 - 1.05)L2. In this way, not only can it ensure that the liquid medicine is completely discharged and improve the drug utilization rate, but also ensure that when the excitation rod 11 completes the downward stroke, the piston 22 just pushes the liquid medicine of the preset volume, thereby ensuring that the volume error of the liquid medicine injected each time can be controlled within a very small range and the accuracy of the drug dose is achieved.

[0076] As a design preference, as Figure 15 shown in the figure, the spring receiving member 32 is composed of a body 321, a left elastic arm 322, a right elastic arm 323, and a middle auxiliary positioning column 324. Among them, the left elastic arm 322, the right elastic arm 323, and the middle auxiliary positioning column 324 all extend downward from the body 321, and the three work together to achieve the design purposes of restraining, positioning, and energy storage of the excitation spring 31. And the left elastic arm 322 and the right elastic arm 323 are symmetrically distributed along the central axis of the middle auxiliary positioning column 324.

[0077] As Figure 4As shown, when the injection force excitation mechanism is assembled, the left elastic arm 322 and the right elastic arm 323 are surrounded and constrained by the inner body 12, and the upper limit of their axial movement is limited to ensure that the excitation spring 31 can be compressed and store energy. The excitation spring 31 is penetrated by the middle auxiliary positioning post 324. In this way, on the one hand, due to the surrounding constraint design of the inner body 12, the left elastic arm 322 and the right elastic arm 323 are synchronously stressed, ensuring that the excitation spring 31 is evenly stressed during the compression process, and then providing a stable axial thrust when released, guaranteeing the linearity of the movement of the excitation rod 12 and the injection accuracy. On the other hand, through the cooperation of the cylindrical surface and the inner diameter of the excitation spring 31, the radial offset of the upper end of the excitation spring 31 can be controlled within a reasonable range, avoiding bending or radial swing of the excitation spring 31 during compression, and ensuring that the elastic potential energy is released axially in a directional manner.

[0078] It is known that according to design common sense, various design structures can be adopted to achieve the effective assembly of the spring receiving member 32 relative to the inner body 12. However, here a design structure is recommended, which is easy to manufacture and implement, and has excellent embedding stability. Specifically, as Figures 11 - 13 shown, the inner side wall of the inner body 12 undergoes a material removal process to form a left limiting groove 122 adapted to the left elastic arm 332 and a right limiting groove 123 adapted to the right elastic arm 323, so as to form an embedded constraint structure for the spring receiving member 32. And the left limiting groove 122 and the right limiting groove 123 cooperate to form a radial surrounding constraint on the spring receiving member 32 (not shown in the figure). When the excitation spring 31 is compressed, the radial expansion forces of the left elastic arm 332 and the right elastic arm 323 are offset, avoiding structural deformation of the left elastic arm 332 and the right elastic arm 323 caused by outward expansion.

[0079] As a further optimization of the above technical solution, the left limiting groove 122 and the right limiting groove 123 have the same design dimensions. Taking the left limiting groove 122 as an example, its depth is controlled within 0.5 - 1.2 mm, and the groove width is 0.1 - 0.2 mm larger than the thickness of the left elastic arm 332. In this way, when the excitation spring 31 is compressed, the left elastic arm 332 and the right elastic arm 323 can not only maintain accurate axial positioning through the constraint of the inner body 12, but also release sufficient elastic potential energy during excitation (such as after the radial spring-back arm 1211 is unlocked), pushing the excitation rod 11 to move smoothly.

[0080] As Figure 16As shown in the figure, an upper radially extending anti - detachment structure 41 and a lower radially resilient damping structure 42 are axially spaced along the starting shell 4. The upper radially extending anti - detachment structure 41 consists of two upper radially extending anti - detachment protrusions 411 distributed in an axially symmetric state. The upper radially extending anti - detachment protrusion 411 is formed by continuously radially extending from the circumferential outer wall of the starting shell 4. The lower radially resilient damping structure 42 consists of two radially resilient damping hook arms 421 distributed in an axially symmetric state. The radially resilient damping hook arm 421 is formed by slitting and removing materials from the circumferential outer wall of the starting shell 4. As Figures 17 - 19 shown in the figure, an upper blocking step 61 and a lower blocking step 62 are spaced on the inner side wall of the lower outer shell 6.

[0081] As Figure 5 shown in the figure, in the initial state, the upper radially extending anti - detachment protrusion 411 abuts against the upper blocking step 61, while the radially resilient damping hook arm 421 is in critical contact with the lower blocking step 62 (that is, there is an axial gap of 0.1 - 0.3 mm between the radially resilient damping hook arm 421 and the lower blocking step 62).

[0082] When the emergency injection pen is activated, during the process of the starting shell 4 moving upward, the radially resilient damping hook arm 421 abuts against the lower blocking step 62, and the radially resilient damping hook arm 421 radially elastically contracts by itself due to the reaction force from the lower blocking step 62. At the same time, the upper radially extending anti - detachment protrusion 411 gradually moves away from the upper blocking step 61. As the upward movement process of the starting shell 4 continues, the radially resilient damping hook arm 421 can cross the upper blocking step 61, and it radially expands by itself due to the loss of physical constraint;

[0083] After the injection is completed, the starting shell 4 moves downward due to the pushing force from the outer main body 13 until the expanded radially resilient damping hook arm 421 abuts against the upper blocking step 61. After the injection is completed, the auxiliary spring 33 releases energy to push the outer main body 13 downward, driving the starting shell 4 to move downward along the inner wall of the lower outer shell 6, and the lower radially resilient damping hook arm 421 moves downward accordingly. When it crosses the lower blocking step 62, the expanded radially resilient damping hook arm 421 abuts against the upper blocking step 61, thus accurately limiting the extreme downward movement stroke of the starting shell 4. Through the dynamic cooperation between the upper radially extending anti - detachment protrusion 411, the radially resilient damping hook arm 421, the upper blocking step 61 and the lower blocking step 62, accurate limit and reliable guidance for the whole movement process of the starting shell 4 are achieved.

[0084] Finally, it should be noted that when the injection needle 23 is hidden, the starter shell 4 is flush with the bottom end of the lower shell 6, or the starter shell 4 is retracted into the lower shell 6 by 0.5-1.0 mm. In this way, on the one hand, the injection needle 23 is completely hidden inside the starter shell 4, and the protection of the injection needle 23 is enhanced by the physical barrier of the lower shell 6, which is conducive to eliminating the risk of the injection needle 23 being exposed due to the starter shell 4 not being moved down to its proper position.

[0085] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An emergency injection pen, characterized in that, It includes a firing force locking mechanism, a PFS assembly, a driving assembly, a starting shell, an upper shell and a lower shell that cooperate to achieve initial locking, firing injection and needle retraction functions during the injection process; The PFS assembly is received by the starting shell and includes a syringe barrel, a piston and an injection needle; the starting shell is sleeved in the lower shell; The firing force locking mechanism includes a firing rod, an inner body and an outer body that are sequentially sleeved from the inside out; the firing rod is formed with an upper radially extending limiting structure, the inner body is formed with a radially resilient blocking structure, and the outer body is formed with an avoidance notch; The driving assembly includes a firing spring and a spring receiving member sleeved around the firing rod, and an auxiliary spring compressed between the upper shell and the outer body; the firing spring is received by the spring receiving member and axially pressed, and is inserted into the accommodating cavity of the firing rod; In the initial state, the radially resilient blocking structure is misaligned with the avoidance notch, and is surrounded and constrained by the outer body, the axial displacement of the firing rod is limited, the firing spring is compressed, the auxiliary spring is in a natural length or slightly compressed state, the injection needle is hidden in the starting shell, and the starting shell and the lower shell maintain the initial assembly position; In the fired state, the starting shell is pushed up by human touch, pushing the outer body to move up, the avoidance notch is aligned with the radially resilient blocking structure, and the radially resilient blocking structure expands under the radial component force of the upper radially extending limiting structure to unlock the firing rod, and the firing spring releases potential energy to push the firing rod down to drive the piston to complete the injection. At the same time, the auxiliary spring is compressed and stores energy due to the relative movement of the upper shell and the outer body; In the state after injection is completed, the starting shell is separated from the human body, and the auxiliary spring releases energy to push the outer body down, synchronously driving the starting shell to move down in the lower shell, so that the needle is hidden in the starting shell again.

2. The emergency injection pen according to claim 1, wherein The upper radially extending limiting structure includes n built-in limiting protrusions evenly distributed along the circumference of the firing rod; the radially resilient blocking structure includes n radially resilient arms formed by slitting the circumference of the inner body; the number of avoidance notches is also n; an external limiting protrusion is provided at the free end of the radially resilient arm to be adapted to the built-in limiting protrusion, and n≥1.

3. The first aid injection pen according to claim 2, characterized in that, The built-in limiting protrusion is formed with an inner upper sliding guiding surface and an inner lower sliding guiding surface after bevel cutting; the external limiting protrusion is formed with an external upper sliding guiding surface adapted to the inner lower sliding guiding surface and an external lower sliding guiding surface adapted to the inner upper sliding guiding surface after bevel cutting.

4. The first aid injection pen according to claim 3, wherein The radially resilient arm has an elastic modulus of 1.8 - 2.5 GPa, an unlocking force of 8 - 12 N, and has a gradually changing thickness structure, with a root thickness of 1 - 1.5 mm, a free end thickness of 0.5 - 0.8 mm, and the length L satisfies L=(D·tanα) / 2 + 2t, where D is the outer diameter of the firing rod, α is the horizontal angle of the inner lower sliding guiding surface, and t is the radial thickness of the built-in limiting protrusion.

5. The emergency injection pen according to any one of claims 1-4, characterized in that The excitation rod is also formed with a lower radially extended limiting structure; the lower radially extended limiting structure includes m arc-shaped limiting bodies, m≥2, and are circumferentially evenly distributed around the central axis of the excitation rod; the tail of the syringe barrel is formed with an annular stop edge that abuts against the arc-shaped limiting body; the perpendicularity tolerance between the annular stop edge and the central axis of the syringe barrel is ≤0.05mm.

6. The first aid injection pen according to claim 5, characterized in that, The axial distance L1 between the upper radially outward extending limit structure and the lower radially outward extending limit structure, and the axial distance L2 from the initial position of the piston to the bottom of the syringe barrel, then satisfy L1=(0.95-1.05)L2; during the downward movement of the excitation rod, when the arc-shaped limit body contacts the annular stop edge, the piston just reaches the bottom of the syringe barrel.

7. The emergency injection pen according to any one of claims 1-4, characterized in that, The spring storage component includes a main body, a left elastic arm, a right elastic arm and a middle auxiliary positioning column; the left elastic arm and the right elastic arm are symmetrically distributed along the central axis of the middle auxiliary positioning column; the middle auxiliary positioning column penetrates the excitation spring to control the radial offset of its upper end.

8. The first aid injection pen according to claim 7, wherein The inner side wall of the inner main body is formed with a left-positioned limit groove adapted to the left-positioned elastic arm and a right-positioned limit groove adapted to the right-positioned elastic arm; the left-positioned limit groove has a depth of 0.5 to 1.2 mm, and a groove width that is 0.1 to 0.2 mm greater than the thickness of the left elastic arm; the right-positioned limit groove has a depth of 0.5 to 1.2 mm, and a groove width that is 0.1 to 0.2 mm greater than the thickness of the right elastic arm.

9. The first-aid injection pen according to claim 1, wherein The starting shell is axially provided with an upper radial outward anti-slip structure and a lower radial rebound damping structure; an upper resistance step and a lower resistance step are provided on the inner side wall of the lower shell; in an initial state, the upper radial outward anti-slip structure contacts the upper resistance step, and the lower radial rebound damping structure maintains an axial gap of 0.1 to 0.3 mm with the lower resistance step; when the starting shell is moved upward by the contact, the lower radial rebound damping structure contracts radially and passes over the lower resistance step; after injection is completed, the lower radial rebound damping structure expands radially and contacts the upper resistance step, and the maximum downward movement stroke of the starting shell is limited.

10. The emergency injection pen according to claim 9, characterized in that, The upper radial outward anti-slip structure includes q upper radial outward anti-slip protrusions, and the lower radial rebound damping structure includes q radial rebound damping hook arms, q≥1; the radial rebound damping hook arms are formed by cutting the circumferential side of the starting shell, and when excited, they are radially contracted by the reaction force of the lower resistance step to cross the lower resistance step, and after injection, they are radially expanded and touch the upper resistance step.

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