Excitation force locking mechanism and first-aid injection pen comprising same
Through the dynamic collaborative design of the radial rebound blocking structure and the extended limiting structure, reliable locking and automatic unlocking of the emergency injection pen are achieved, solving the problems of unlocking lag and locking failure in traditional designs, and improving operational safety and response speed.
Patent Information
- Application Number
- CN202510767828.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-10
- Publication Date
- 2025-09-23
AI Technical Summary
The activation mechanism of traditional emergency injection pens has insufficient radial constraint and axial displacement linkage, which leads to unlocking lag or false touch, and structural wear can easily lead to locking failure. It lacks dynamic adaptive capabilities and cannot achieve reliable locking and automatic unlocking.
The dynamic collaborative design of radial and axial structures is adopted, and the mechanical interlocking of the radial rebound blocking structure and the extended limit structure is used to achieve initial locking and automatic unlocking after triggering. The inclined surface geometry design is used to convert the axial force into a radial component force, driving the expansion of the rebound structure to ensure irreversible locking after a single trigger.
It improves operational safety, simplifies the activation process, avoids the risk of locking failure caused by elastic force attenuation in traditional spring structures, achieves fast and direct unlocking response, and solves the risk of repeated injection caused by misoperation.
Smart Images
Figure CN120679037A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of medical device manufacturing, in particular to an excitation force locking mechanism and an emergency injection pen comprising the same. Background Art
[0002] As a portable medical device, the emergency injection pen is widely used in scenarios such as insulin injection and emergency drug injection. Its core lies in achieving precise dosage control, safe triggering and preventing reuse through mechanical structure.
[0003] As far as the current status of the industry is concerned, the activation and locking mechanism of the emergency injection pen has the following core problems: 1) The traditional activation mechanism has insufficient linkage between radial constraint and axial displacement. For example, some solutions use mechanical engaging structures (such as locking protrusions and slots) to achieve limitation, but the release of radial constraint relies on spring reset or manual intervention, resulting in a lag in unlocking of axial displacement and the possibility of false touch; 2) The coordination of radial deformation structures such as metal springs and axial movements relies on compensation from auxiliary components. For example, in the solution that achieves adjustment through the engagement of spring protrusions and tooth grooves, the decoupling design of the radial expansion freedom of the spring and the axial displacement is not direct enough, and long-term use may cause locking failure due to structural wear; 3) In the axial assembly structure, the coordination of radial constraint and axial movement relies on static limitation of the fixing parts, lacks dynamic self-adaptation capability during activation, and cannot achieve active decoupling and one-way unlocking through structural linkage during the activation process. Therefore, technical personnel are urgently needed to solve the above problems. Summary of the Invention
[0004] The present invention aims to provide an excitation force locking mechanism, which realizes reliable locking before triggering and automatic unlocking after triggering of the emergency injection pen through dynamic coordination of radial structure and axial structure, thereby improving operational safety.
[0005] The invention relates to an excitation force locking mechanism, which comprises an excitation rod, an inner body and an outer body which are sequentially mounted from the inside out.
[0006] A radial extension limit structure is formed on the excitation rod near its top, a radial rebound blocking structure is formed on the inner body near its top, and an avoidance notch is formed on the outer body.
[0007] In the initial state, the radial rebound blocking structure and the avoidance notch are dislocated with each other and are surrounded by the outer body, so that the radial expansion freedom is constrained. The extension limiting structure is subject to the blocking force from the radial rebound blocking structure, so that the axial displacement freedom is restricted.
[0008] After the emergency injection pen is activated, the outer body moves upward due to the axial pushing force until the radial rebound blocking structure is aligned with the avoidance gap. The radial rebound blocking structure expands radially due to the radial component force from the extension limiting structure, and as the activation rod continues to move downward, the extension limiting structure is able to pass over the radial rebound blocking structure. At this time, the activation rod has axial displacement freedom.
[0009] As a further improvement of the technical solution disclosed in the present invention, the radially outward extension limiting structure includes N built-in limiting protrusions. The built-in limiting protrusions are formed by continuing to radially extend the circumferential outer wall of the excitation rod. The radial rebound blocking structure includes N radial rebound arms. The radial rebound arms are formed by cutting and removing material from the circumferential outer wall of the inner body, and an external limiting protrusion that is compatible with the built-in limiting protrusion is formed near its free end. The avoidance notch is formed by removing material from the circumferential outer wall of the outer body, and the number of the avoidance notch is N; N ≥ 1.
[0010] As a further improvement to the technical solution disclosed in the present invention, the internal limiting protrusion undergoes a bevel cutting process, and an internal upper sliding guide surface is formed on its top wall, and an internal lower sliding guide surface is formed on its bottom wall. The external limiting protrusion undergoes a bevel cutting process, and an external upper sliding guide surface that matches the internal lower sliding guide surface is formed on its top wall, and an external lower sliding guide surface that matches the internal upper sliding guide surface is formed on its bottom wall.
[0011] As a further improvement to the technical solution disclosed in the present invention, the elastic modulus of the radial rebound arm is controlled within 1.8 to 2.5 GPa, and the unlocking force is maintained at 8 to 12 N. The radial rebound arm has a thickness gradient structure, with a root thickness of 1 to 1.5 mm and a free end thickness of 0.5 to 0.8 mm, and its length L satisfies the formula:
[0012] L = (D*tanα) / 2+2t;
[0013] Wherein, D is the outer diameter of the excitation rod, α is the horizontal angle of the built-in lower sliding guide surface, and t is the radial thickness of the built-in limiting protrusion.
[0014] As a further improvement of the technical solution disclosed in the present invention, the built-in upper sliding guide surface, the built-in lower sliding guide surface, the external upper sliding guide surface and the external lower sliding guide surface are all subjected to chemical vapor deposition treatment to form a self-lubricating coating, and the thickness is controlled at 0.5 to 1 μm.
[0015] As a further improvement of the technical solution disclosed in the present invention, the inner body material is preferably any one of polycarbonate, polyamide, polyoxymethylene, and polypropylene.
[0016] As a further improvement to the disclosed technical solution, M anti-deflection extension protrusions are formed on the circumferential outer wall of the trigger rod at a set distance from the radial extension limit structure. After material removal, M anti-deflection limit grooves are formed on the circumferential inner wall of the inner body, matching the anti-deflection extension protrusions; M ≥ 1.
[0017] As a further improvement of the technical solution disclosed in the present invention, when the anti-deflection extension protrusion and the anti-deflection limit groove are aligned, a gap is formed between the two, and the single-side gap value is controlled at 0.2 to 0.3 mm.
[0018] As a further improvement to the disclosed technical solution, an annular damping groove is formed on the circumferential inner wall of the outer body, and an O-ring is embedded in the damping groove. Initially, the O-ring forms an interference fit with the circumferential outer wall of the inner body. When the outer body moves upward, the inner body is subjected to a damping force from the O-ring.
[0019] Furthermore, the present invention also discloses an emergency injection pen, which includes the above-mentioned excitation force locking mechanism.
[0020] The working principle of the excitation force locking mechanism disclosed in the present invention is roughly as follows:
[0021] In the initial state, the radial rebound blocking structure is surrounded by the outer body, physically blocking its radial expansion path to ensure its structural stability in the initial state; the radial extension limiting structure and the radial rebound blocking structure form a mechanical interlock to prevent the trigger rod from moving downward; the avoidance notch and the radial rebound blocking structure are offset from each other to form a physical isolation to prevent accidental unlocking due to external forces, thus meeting the "zero false touch" design requirement;
[0022] During the excitation process, the outer body moves upward due to the axial pushing force until the avoidance notch is aligned with the radial rebound blocking structure, thereby releasing the radial embracing constraint on the radial rebound blocking structure; the excitation rod begins to move downward under the action of gravity or spring force, and the radial extension limiting structure contacts the radial rebound blocking structure, and the axial force is converted into a radial component force through the inclined surface geometry design, driving the radial rebound blocking structure to expand outward; and after the radial rebound blocking structure expands, the extension limiting structure is able to smoothly cross the blocking position. At this time, the outer body remains in an upward state due to the pushing force, and the radial rebound blocking structure contracts again due to elastic reset, but the extension limiting structure has passed, thereby forming an irreversible unlocking after a single trigger.
[0023] When injection is complete, the trigger rod moves downward after injection is complete, and the avoidance notch and the radial rebound blocking structure become misaligned again, allowing the outer body to re-embrace the rebound structure, limiting its radial expansion. At this point, the radial extension limiter is already below the radial rebound blocking structure. Even if a pushing force is applied to the outer body again, the radial rebound blocking structure is constrained by the outer body and cannot expand, preventing the trigger rod from being released again.
[0024] In practical applications, the excitation force locking mechanism disclosed in the present invention can achieve at least the following beneficial technical effects, specifically:
[0025] 1) The outer body embraces the radial rebound blocking structure, forming a physical constraint on its radial expansion. Simultaneously, the radial extension limiter structure and the radial rebound blocking structure are mechanically interlocked to lock the axial displacement of the trigger rod. Rigid locking is achieved solely through the geometric coordination of the outer and inner bodies, thereby avoiding the risk of locking failure due to elastic force attenuation in traditional spring structures and improving the stability of the locked state.
[0026] 2) When the avoidance notch is aligned with the radial rebound blocking structure and the trigger rod moves downward, the radial rebound blocking structure expands due to the radial force component from the radial extension limit structure. This structural geometric design achieves active decoupling of the radial constraint, greatly simplifying the triggering process and making the unlocking response more direct, which is particularly suitable for the rapid operation requirements in emergency scenarios.
[0027] 3) After the radial rebound blocking structure passes over the radial rebound blocking structure and the emergency injection pen completes the injection, the radial rebound blocking structure and the avoidance gap are misaligned again, and it can be re-encircled and constrained, thereby preventing it from expanding again. In this way, the design goal of physical irreversible locking 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 the traditional design. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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 any creative work.
[0029] Figure 1 It is a three-dimensional schematic diagram of the first aid injection pen disclosed in the present invention.
[0030] Figure 2 yes Figure 1 side view.
[0031] Figure 3 yes Figure 2 AA cross-sectional view.
[0032] Figure 4 yes Figure 3 A magnified view of the I part.
[0033] Figure 5 It is a three-dimensional schematic diagram of the excitation rod in the excitation force locking mechanism disclosed in the present invention.
[0034] Figure 6 It is a three-dimensional schematic diagram of the inner body in the excitation force locking mechanism disclosed in the present invention.
[0035] Figure 7 yes Figure 6 side view.
[0036] Figure 8 yes Figure 7 CC cross-sectional view.
[0037] Figure 9 It is a three-dimensional schematic diagram of the outer body of the excitation force locking mechanism disclosed in the present invention.
[0038] Figure 10 yes Figure 4 Partially enlarged view of II.
[0039] Figure 11 yes Figure 3 BB cross-sectional view.
[0040] Figure 12 This is a schematic diagram of the action flow of the excitation force locking mechanism disclosed in the present invention (in sequence: initial state, excitation rod critical triggering state and triggering completion state).
[0041] 1-excitation rod; 11-radial extension limiting structure; 111-internal limiting protrusion; 1111-internal upper sliding guide surface; 1112-internal lower sliding guide surface; 12-anti-deflection extension protrusion; 2-inner body; 21-radial rebound blocking structure; 211-radial rebound arm; 2111-external limiting protrusion; 21111-external upper sliding guide surface; 21112-external lower sliding guide surface; 22-anti-deflection limiting groove; 3-outer body; 31-avoidance gap. DETAILED DESCRIPTION
[0042] In the description of the present invention, it should be understood that the positions or positional relationships indicated by terms such as "left", "right", "front", "back", "up", and "down" are based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific position, be constructed and operate in a specific position, and therefore cannot be understood as a limitation on the present invention.
[0043] The emergency injection pen is a portable automatic injection device designed specifically for emergency treatment scenarios, used to quickly and accurately deliver emergency medications (such as epinephrine and insulin). Its core function is to quickly complete puncture and medication delivery. The trigger lock mechanism is the core safety control unit of the emergency injection pen, directly determining its effectiveness and safety in emergency situations.
[0044] The excitation force locking mechanism disclosed in the present invention is further described in detail below with reference to specific embodiments. Figures 1 to 4 As shown in FIG, the excitation force locking mechanism is mainly composed of an excitation rod 1, an inner body 2 and an outer body 3, which are assembled in sequence from the inside to the outside.
[0045] like Figure 5 As shown in FIG, near its top, the excitation rod 1 is formed with a radially extending limiting structure 11. The radially extending limiting structure 11 is composed of two oppositely disposed internal limiting protrusions 111. The internal limiting protrusions 111 are formed by the circumferential outer wall of the excitation rod 1 continuing to radially extend.
[0046] like Figures 6-8 As shown in FIG, a radial rebound prevention structure 21 is formed on the inner body 2 near its top end. To accommodate the radially outward-extending limiting structure 11, the radial rebound prevention structure 21 comprises two opposing radial rebound arms 211. The radial rebound arms 211 are formed by cutting and removing material from the circumferential outer wall of the inner body 2, and an outward-positioned limiting protrusion 2111 is formed near its free end.
[0047] like Figure 9 As shown in FIG, near its bottom end, the outer body 3 is formed with two opposite avoidance notches 31 to match the radial rebound blocking structure 21.
[0048] As Figure 12 As shown in FIG, in the initial state, the avoidance notch 31 and the radial rebound arm 211 are axially offset, and the outer body 3 encircles and restrains the radial rebound arm 211, physically limiting its radial expansion. The internal limiting protrusion 111 contacts the external limiting protrusion 2111 to form a mechanical interlock, preventing the trigger rod 1 from performing axial downward movement.
[0049] During the activation and unlocking phase, when the emergency injection pen is activated, an external force pushes the outer body 3 axially to cause it to move upward until the avoidance notch 31 and the radial rebound arm 211 are completely aligned axially. At this point, the outer body 3 releases the radial embracing constraint on the radial rebound arm 211. The activation rod 1 begins to move downward under the action of gravity or spring force, and the internal limiting protrusion 11 contacts the external limiting protrusion 2111. The axial force is converted into a radial component force through the inclined geometric design, driving each radial rebound arm 211 to expand outward. After the radial rebound arm 211 expands, each internal limiting protrusion 11 is able to smoothly pass over the corresponding external limiting protrusion 2111. At this time, the outer body 3 remains in the upward state, and each radial rebound arm 211 contracts radially due to elastic reset. However, the internal limiting protrusion 111 has left the blocking area, and the activation rod 1 obtains the axial displacement freedom, completing the unlocking.
[0050] When injection is complete, after the trigger rod 1 has completed the injection and moved downward, the outer body 3 loses its pushing force and falls back. Each radial rebound arm 211 is again misaligned with the avoidance notch 31 and is radially embraced by the outer body 3, thus limiting the radial expansion freedom of each radial rebound arm 211. At this point, the internal limiting protrusion 111 has moved below the external limiting protrusion 2111. Even if a pushing force is applied to the outer body 3 again, each radial rebound arm 211 cannot expand due to being constrained by the outer body 3, thus preventing the trigger rod 1 from being released again.
[0051] By adopting the above-mentioned technical solution, on the one hand, the outer body 3 embraces the radial rebound arm 211 to form a physical constraint on its radial expansion, and at the same time utilizes the mechanical interlocking mechanism of the built-in limiting protrusion 111 and the external limiting protrusion 2111 to lock the axial displacement freedom of the excitation rod 1, and rigid locking can be achieved only by the geometric cooperation of the outer body 3 and the inner body 2, thereby avoiding the risk of locking failure caused by elastic force attenuation of the traditional spring structure and improving the stability of the locked state; on the other hand, when the avoidance notch 31 is aligned with the radial rebound arm 211 and the excitation rod 1 moves downward, each radial rebound arm 211 expands itself due to the radial component force from the corresponding built-in limiting protrusion 111, and the active decoupling of the radial constraint is achieved through the structural geometric design, thereby greatly simplifying the excitation process and making the unlocking response more direct, which is particularly suitable for the rapid operation requirements in emergency scenarios.
[0052] Here, it is particularly important to emphasize that after the built-in limiting protrusion 111 passes over the external limiting protrusion 2111 and the emergency injection pen completes the injection, each radial rebound arm 211 is misaligned with the avoidance gap 31 again, and is able to be re-encircled and constrained by the outer body 3, thereby preventing it from expanding again. In this way, the design goal of physical irreversible locking after a single trigger is achieved, and the secondary trigger path is directly blocked by the mechanical structure, thereby solving the risk of repeated injection caused by misoperation in the traditional design.
[0053] As a further optimization of the above technical solution, Figures 5 to 8 、 Figure 10 As shown in , the internal limiting protrusion 111 undergoes a bevel cutting process, and a built-in upper sliding guide surface 1111 is formed on its top wall, and a built-in lower sliding guide surface 1112 is formed on its bottom wall. The external limiting protrusion 2111 undergoes a bevel cutting process, and an external upper sliding guide surface 21111 that matches the internal lower sliding guide surface 1112 is formed on its top wall, and an external lower sliding guide surface 21112 that matches the internal upper sliding guide surface 1111 is formed on its bottom wall. In this way, on the one hand, the angle design of the internal upper sliding guide surface 1111 and the external lower sliding guide surface 21112 allows the axial force to be efficiently decomposed into a radial expansion force F r and tangential slip force F t , it can generate sufficient radial expansion force under a smaller axial thrust to reduce the energy threshold required for unlocking; on the other hand, when unlocking, the built-in lower sliding guide surface 1112 and the external upper sliding guide surface 21111 touch each other, guiding the radial rebound arm 211 to expand radially and smoothly; then the built-in upper sliding guide surface 1111 and the external lower sliding guide surface 21112 cooperate to ensure that there is no jamming during the crossing process.
[0054] Based on long-term manufacturing and production experience, the elastic modulus of the radial rebound arm 211 is also controlled at 1.8~2.5GPa, which is suitable for medical-grade plastics such as polycarbonate, polyamide, polyoxymethylene, and polypropylene. While ensuring that the material has good elastic recovery ability, it avoids the brittle risk of high-modulus materials.
[0055] Furthermore, the unlocking force of the radial rebound arm 211 is preferably maintained at 8 to 12 N. This can ensure that the emergency injection pen can be triggered quickly and prevent misoperation due to accidents such as collisions during daily carrying.
[0056] As a preferred design structure, the radial rebound arm 211 also has a thickness gradient structure, with a root thickness of 1 to 1.5 mm and a free end thickness of 0.5 to 0.8 mm, and its length L satisfies the formula:
[0057] L = (D*tanα) / 2+2t;
[0058] Where D is the outer diameter of the trigger rod 1, α is the horizontal angle of the internal lower sliding guide surface 1112, and t is the radial thickness of the internal stop protrusion 111. The value (D * tanα) ensures that when the rebound arm 211 expands, the free end displacement allows the internal stop protrusion 111 to smoothly pass over the opposing external stop protrusion 2111. The value +2t is a safety margin to compensate for the Poisson effect of the material and manufacturing tolerances, ensuring a smooth and stable unlocking process.
[0059] Furthermore, to reduce the coefficient of friction and improve the smoothness of the unlocking operation, as a further optimization of the above-mentioned technical solution, the internal upper sliding guide surface 1111, the internal lower sliding guide surface 1112, the external upper sliding guide surface 21111, and the external lower sliding guide surface 21112 are all treated with chemical vapor deposition to form a self-lubricating coating with a thickness controlled to 0.5 to 1 μm. Thanks to the presence of the self-lubricating coating, the interfacial friction coefficient is significantly reduced, thereby directly reducing the mechanical resistance associated with unlocking and avoiding the "stuck-sudden sliding" phenomenon caused by fluctuations in friction resistance in traditional structures.
[0060] like Figures 3 to 8 、 Figure 11 As shown in FIG, two anti-deflection extension protrusions 12 are formed on the circumferential outer wall of the trigger rod 1 at a set distance from the internal limiting protrusion 111. After material removal, two anti-deflection limiting grooves 22 are formed on the circumferential inner wall of the inner body 2 to match the anti-deflection extension protrusions 12. When the anti-deflection extension protrusions 12 and the anti-deflection limiting grooves 22 are aligned, a gap is formed between them, with the single-side gap value controlled to be 0.2-0.3 mm. In this way, in actual application, the anti-deflection extended protrusion 12 and the anti-deflection limit groove 22 opposite to it form a "protrusion-groove" cooperation, and the circumferential rotational freedom of the excitation rod 1 is limited within the design range through geometric constraints, ensuring that the excitation rod 1 only moves axially when unlocking / locking, avoiding the occurrence of misalignment or jamming of the built-in limit protrusion 111 and the external limit protrusion 2111 due to circumferential deflection movement, and being compatible with manufacturing errors while suppressing the circumferential deflection amplitude of the excitation rod 1, thereby achieving the comprehensive effect of "precise guidance without jamming and dynamic buffering without damage".
[0061] Furthermore, as another preferred design of the above technical solution, the circumferential inner wall of the outer body 3 is formed with an annular damping groove, and an O-ring is embedded in the damping groove (not shown in the figure). In the initial state, the O-ring is interference fit with the circumferential outer wall of the inner body 2. When the outer body 3 performs an upward movement, the inner body 2 is always subjected to the damping force from the O-ring. In this way, the O-ring in the interference fit state holds the inner body 2 circumferentially and generates a controllable viscous damping force. The existence of the damping force increases the threshold for accidental touch unlocking, avoids the occurrence of accidental erroneous unlocking of the emergency injection pen, and improves its operational safety and controllability.
[0062] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily 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 is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. An excitation force locking mechanism, characterized in that: The device comprises an excitation rod, an inner body and an outer body which are assembled in sequence from the inside out; Near its top end, the excitation rod is formed with a radial extension limit structure; near its top end, the inner body is formed with a radial rebound blocking structure; and the outer body is formed with an avoidance notch; In the initial state, the radial rebound blocking structure and the avoidance notch are offset from each other and are surrounded by the outer body, so that the radial expansion freedom is constrained. The extension limiting structure is subject to the blocking force from the radial rebound blocking structure, so that the axial displacement freedom is restricted. After the emergency injection pen is activated, the outer body moves upward due to the axial pushing force until the radial rebound blocking structure is aligned with the avoidance gap. The radial rebound blocking structure expands radially due to the radial component force from the extension limiting structure, and as the downward movement of the activation rod continues, the extension limiting structure is able to pass over the radial rebound blocking structure. At this time, the activation rod has axial displacement freedom.
2. The excitation force locking mechanism according to claim 1, characterized in that: The radially outward extension limiting structure includes N built-in limiting protrusions; the built-in limiting protrusions are formed by continuing to radially extend from the circumferential outer wall of the excitation rod; the radial rebound blocking structure includes N radial rebound arms; the radial rebound arms are formed by cutting and removing material from the circumferential outer wall of the inner body, and an external limiting protrusion that is compatible with the built-in limiting protrusion is formed near its free end; the avoidance notch is formed by removing material from the circumferential outer wall of the outer body, and its number is N; N≥1.
3. The excitation force locking mechanism according to claim 2, characterized in that: The built-in limiting protrusion undergoes a bevel cutting process, and a built-in upper sliding guide surface is formed on its top wall, and a built-in lower sliding guide surface is formed on its bottom wall; the external limiting protrusion undergoes a bevel cutting process, and an external upper sliding guide surface that is compatible with the built-in lower sliding guide surface is formed on its top wall, and an external lower sliding guide surface that is compatible with the built-in upper sliding guide surface is formed on its bottom wall.
4. The excitation force locking mechanism according to claim 3, characterized in that: The elastic modulus of the radial rebound arm is controlled at 1.8 to 2.5 GPa, and the unlocking force is maintained at 8 to 12 N. The radial rebound arm has a thickness gradient structure, with a root thickness of 1 to 1.5 mm and a free end thickness of 0.5 to 0.8 mm, and its length L satisfies the formula: L = (D*tanα) / 2+2t; Wherein, D is the outer diameter of the excitation rod, α is the horizontal angle of the built-in lower sliding guide surface, and t is the radial thickness of the built-in limiting protrusion.
5. The excitation force locking mechanism according to claim 3, characterized in that: The built-in upper sliding guide surface, the built-in lower sliding guide surface, the external upper sliding guide surface and the external lower sliding guide surface are all subjected to chemical vapor deposition treatment to form a self-lubricating coating, and the thickness is controlled to be 0.5-1 μm.
6. The excitation force locking mechanism according to claim 2, characterized in that: The inner body is made of any one of polycarbonate, polyamide, polyoxymethylene, and polypropylene.
7. The excitation force locking mechanism according to any one of claims 1 to 6, characterized in that: M anti-deflection extension protrusions are formed on the circumferential outer side wall of the excitation rod at a set distance from the radial extension limit structure; after material removal processing, M anti-deflection limit grooves matching the anti-deflection extension protrusions are formed on the circumferential inner side wall of the inner body; M ≥ 1.
8. The excitation force locking mechanism according to claim 7, characterized in that: When the anti-deflection extension protrusion and the anti-deflection limiting groove are aligned, a gap is formed between the two, and the single-side gap value is controlled to be 0.2-0.3 mm.
9. The excitation force locking mechanism according to any one of claims 1 to 6, characterized in that: An annular damping groove is formed on the circumferential inner side wall of the outer body, and an O-ring is embedded in the damping groove; in an initial state, the O-ring is interference fit with the circumferential outer side wall of the inner body; when the outer body performs an upward movement, the inner body is subjected to the damping force from the O-ring.
10. An emergency injection pen, characterized in that: The invention comprises an excitation force locking mechanism as described in any one of claims 1 to 9.