Prime clutching arrangement and injection pen therefor

Abstract

The present application belongs to the technical field of hygiene, and particularly relates to a trigger clutch structure and an injection pen. One of the trigger clutch structures comprises: a driving sleeve, which is rotationally arranged in a pen body and has a plurality of key tooth groups uniformly distributed on the inner wall in the circumferential direction; a driving link, which is rotationally arranged in the driving sleeve and has at least two second racks uniformly distributed on the outer wall in the circumferential direction; and a limiting ring, which is rotationally arranged on the outer wall of the driving link and has a plurality of limiting notches uniformly distributed on the outer wall in the circumferential direction. One limiting notch corresponds to one key tooth group, and the opening size of the limiting notch is smaller than the tooth gap between the two second racks. When the dose is adjusted, the driving sleeve is rotated relative to the driving link, and the key tooth group drives the limiting ring to rotate synchronously. When the trigger is triggered, the driving sleeve is axially moved relative to the driving link, the key tooth group is moved relative to the limiting ring and inserted into the tooth gap between the two second racks. After the key tooth group is disengaged from the limiting of the limiting notch, the two side walls of the key tooth group are respectively attached to the side walls of the two second racks.

Description

Technical Field

[0001] This invention belongs to the field of hygiene technology, specifically relating to syringes, and more particularly to a trigger clutch structure and its injection pen. Background Technology

[0002] As a convenient drug delivery tool, the core function of an injection pen is to achieve precise dosage adjustment and safe injection through its internal precision structure.

[0003] In related technologies, current injection pens achieve automatic injection through the interaction of multiple structures, including coil springs, springs, drive sleeves, drive linkages, clutch rods, rotary gears, and push plates. A mainstream approach involves axial displacement of the drive sleeve relative to the drive linkage, causing them to mesh and thus activating the injection pen. Specifically, the inner wall of the drive sleeve is equipped with several first racks, and the outer wall of the drive linkage is equipped with several second racks. Axial displacement of the drive sleeve relative to the drive linkage enables the first and second racks to mesh. However, this mainstream technical solution has a significant drawback:

[0004] When the drive sleeve rotates to the preset dose scale following the dose adjustment button, during the axial displacement to engage the first and second racks, due to manufacturing tolerances and assembly clearances, the center line of the tooth peak of one first rack is difficult to completely coincide with the center line of the tooth valley of the second rack when it is inserted between two adjacent second racks. Even a slight circumferential offset (possibly due to minor circumferential rotation of the drive sleeve relative to the drive linkage or tooth profile error), while not affecting the macroscopic engagement, will cause misaligned contact and collision between the engagement slopes of the first and second racks.

[0005] This misaligned contact generates a tangential force that causes an uncontrollable, minute rotation (typically ±0.5°) in the circumferential direction of the drive linkage. This results in a deviation in the final displacement of the medication stopper. For high-precision dosing pens (especially insulin pens), such micrometer-level displacement deviations are sufficient to cause fluctuations in the injection dose, resulting in a discrepancy between the actual and set doses, severely affecting dosing accuracy and potentially posing risks to patient medication safety.

[0006] Therefore, how to solve the circumferential rotation of the drive linkage caused by the misalignment of the rack meshing is a technical problem that urgently needs to be solved in this field.

[0007] It should be noted that the information disclosed in this background section is only for understanding the background technology of this application concept, and therefore, the above description is not considered to constitute information related to the technology. Summary of the Invention

[0008] This disclosure provides at least one excitation clutch structure and its injection pen.

[0009] In a first aspect, embodiments of this disclosure provide an activation clutch structure, comprising:

[0010] The drive sleeve is rotated inside the pen body, and several key teeth are evenly distributed around its inner wall.

[0011] The drive linkage rotates within the drive sleeve, and its outer wall is provided with at least two second racks in the circumferential direction;

[0012] A limiting ring is rotatably sleeved on the outer wall of the drive connecting rod, and several limiting notches are opened in the circumferential direction of the outer wall;

[0013] A limiting notch accommodates and limits a set of key teeth;

[0014] During dosage adjustment, the drive sleeve rotates relative to the drive linkage, and the key tooth assembly drives the limit ring to rotate synchronously.

[0015] During activation, the drive sleeve moves axially relative to the drive connecting rod, and the key tooth assembly moves relative to the limiting ring and inserts into the tooth gap between the two second racks.

[0016] After the key tooth assembly is released from the limiting notch, the two side walls of the key tooth assembly respectively fit into the side walls of the two second toothed racks.

[0017] In one optional embodiment, the limiting notch is V-shaped, and the horizontal projected area of ​​the limiting notch opening is smaller than the horizontal projected area of ​​the tooth gap between the two second racks.

[0018] In one alternative embodiment, the key tooth assembly is elastic, and when the key tooth assembly is disengaged from the limiting notch, the key tooth assembly is adapted to deform toward the two adjacent second toothed racks.

[0019] In one optional embodiment, the key tooth assembly includes two symmetrically arranged first racks, the first racks having a triangular horizontal projection, and a gap between the two first racks;

[0020] When the two first racks are limited by the limiting notch, their horizontal projected area is smaller than the horizontal projected area of ​​the tooth gap between the two second racks.

[0021] In one optional embodiment, an expansion groove is formed on the outer wall of the first rack, and the axial length of the expansion groove is greater than the axial thickness of the limiting ring.

[0022] The drive sleeve moves axially relative to the drive connecting rod, and the expansion groove is adapted to abut against the side wall of the limiting notch so that the side walls of the two first racks abut against the side walls of the two second racks respectively.

[0023] In one alternative embodiment, an inclined surface is provided on one side wall of the expansion groove near the second rack, the inclined surface being adapted to guide the side wall of the limiting notch into the expansion groove.

[0024] In one optional embodiment, at least one elastic tooth is provided on the outer wall of the end of the drive link away from the drive sleeve;

[0025] The inner wall of the pen body is evenly distributed with a plurality of sound-producing teeth, and the elastic teeth mesh with the sound-producing teeth;

[0026] In this configuration, after the key tooth assembly meshes with the second rack, the coil spring is adapted to drive the drive sleeve and drive connecting rod to rotate, and the elastic teeth sequentially abut against the sound-producing teeth to produce sound.

[0027] Secondly, embodiments of this disclosure also provide an injection pen, comprising:

[0028] The dosage knob is located at one end of the pen body;

[0029] A spring-loaded bracket is installed inside the pen body, and a spring is installed inside it;

[0030] The clutch lever is rotatably mounted inside the coil spring bracket, with one end fixed to the end of the drive sleeve and engaging with the dosage knob;

[0031] During dosage adjustment, the dosage knob drives the clutch lever to rotate, and the clutch lever drives the drive sleeve to rotate synchronously to compress the coil spring.

[0032] In one optional embodiment, a return spring is provided inside the drive sleeve, the return spring is sleeved on the outer wall of the drive connecting rod, and one end of the return spring is fixed to a fixed platform on the outer wall of the drive connecting rod.

[0033] In one optional embodiment, an inner core frame is rotatably disposed inside the coil spring bracket, and the inner end of the coil spring is fixed to the outer wall of the inner core frame.

[0034] The inner core frame has a convex strip axially arranged on its inner wall, and the clutch rod has a sliding groove axially arranged on its outer wall to match the convex strip.

[0035] When the clutch lever rotates, it pushes the inner core frame to rotate synchronously through the protrusion.

[0036] When activated, the clutch lever moves axially relative to the inner core frame, thereby driving the drive sleeve to move axially synchronously.

[0037] In one optional embodiment, a limiting plate is provided at the end of the inner core frame away from the coil spring bracket. The outer diameter of the limiting plate is smaller than the inner diameter of the coil spring bracket, and the limiting plate is adapted to limit the axial movement of the coil spring.

[0038] The beneficial effects of this invention are that it provides an excitation clutch structure and its injection pen. Through the cooperation of the key tooth assembly, the second rack, and the limiting ring, in the initial stage of excitation (when the drive sleeve just begins to move axially towards the second rack), the limiting ring limits the key tooth assembly, preventing misaligned contact collisions on the meshing inclined surfaces during the engagement of the first key tooth with the two second racks. This eliminates minor axial offsets caused by slight circumferential rotation or tooth profile errors of the drive linkage, ensuring the stability of the dosage injection.

[0039] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention are realized and obtained through the structures particularly pointed out in the description and the drawings.

[0040] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the specific embodiments or related technologies of the present invention, the drawings used in the description of the specific embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0042] Figure 1 This is a front view of the drive sleeve and drive connecting rod during the meshing process in the prior art;

[0043] Figure 2 This is a perspective view of the activation clutch structure provided in an embodiment of the present disclosure;

[0044] Figure 3 A perspective view of the drive sleeve and drive linkage when not activated, provided in an embodiment of this disclosure;

[0045] Figure 4 A perspective view of the drive linkage provided in an embodiment of this disclosure;

[0046] Figure 5 A perspective view of the drive sleeve provided in an embodiment of this disclosure;

[0047] Figure 6 A perspective view of the key tooth assembly provided in an embodiment of this disclosure;

[0048] Figure 7 A partial perspective view of the first rack and the limiting ring provided in an embodiment of this disclosure;

[0049] Figure 8A perspective view of the limiting notch inserted into the expansion groove according to an embodiment of this disclosure;

[0050] Figure 9 A cross-sectional front view of the injection pen provided in an embodiment of this disclosure;

[0051] Figure 10 A sectional perspective view of the clutch lever and coil spring bracket provided in an embodiment of this disclosure.

[0052] In the picture:

[0053] 1. Drive sleeve; 10. Return spring;

[0054] 2. Drive linkage; 20. Elastic tooth; 21. Fixed platform;

[0055] 3. Limiting ring; 30. Limiting notch;

[0056] 4. Keyway assembly; 41. First rack; 42. Expansion groove; 43. Inclined surface;

[0057] 5. Second rack;

[0058] 6. Pen body; 60. Vocal teeth;

[0059] 7. Dosage knob;

[0060] 8. Spring support; 80. Inner core frame; 81. Protruding strip; 82. Limiting plate; 83. Spring;

[0061] 9. Clutch lever; 90. Slide groove. Detailed Implementation

[0062] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. 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.

[0063] In this document, when it is mentioned that a first component is located on a second component, this can mean that the first component can be directly formed on the second component, or that a third component can be inserted between the first and second components. Furthermore, in the accompanying drawings, the thickness of the components may be exaggerated or reduced for the purpose of effectively describing the technical content.

[0064] In this document, exemplary embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. As used herein, expressions such as “at least one of…” modify an entire column of elements when following a column of elements. For example, the expression “at least one of a, b, and c” should be understood to include only a, only b, only c, both a and b, both a and c, both b and c, or all of a, b, and c.

[0065] The terminology used herein is for the purpose of describing specific exemplary configurations only and is not intended to be limiting. As used herein, the singular articles “a,” “an,” and “the” may also be intended to include plural forms unless otherwise expressly stated herein. The terms “comprising,” “including,” and “having” are inclusive and thus specify the presence of features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein should not be construed as requiring them to be performed in the specific order discussed or shown, unless specifically identified as such. Additional or alternative steps may be employed.

[0066] As used herein, the phrases “in one embodiment,” “according to one embodiment,” “in some embodiments,” etc., generally refer to the fact that a particular feature, structure, or characteristic following the phrase can be included in at least one embodiment of this disclosure. Therefore, a particular feature, structure, or characteristic can be included in more than one embodiment of this disclosure, such that these phrases do not necessarily refer to the same embodiment. As used herein, the terms “example,” “exemplary,” etc., are used to “serve as an example, instance, or illustration.” Any implementation, aspect, or design described herein as “example” or “exemplary” is not necessarily to be construed as preferred or superior to other implementations, aspects, or designs. Rather, the use of the terms “example,” “exemplary,” etc., is intended to present concepts in a specific manner.

[0067] Research has revealed that current injection pens utilize the interaction of multiple structures, including coil springs, springs, drive sleeves, drive linkages, clutch rods, rotary gears, and push plates, to achieve automatic injection. A mainstream approach involves axial displacement of the drive sleeve relative to the drive linkage, causing them to mesh and thus activating the injection pen. Specifically, the inner wall of the drive sleeve is equipped with several first racks, and the outer wall of the drive linkage is equipped with several second racks. Axial displacement of the drive sleeve relative to the drive linkage enables the first and second racks to mesh. However, this mainstream technical solution has a significant drawback:

[0068] When the drive sleeve rotates to the preset dose scale following the dose adjustment button, during the axial displacement to engage the first and second racks, due to manufacturing tolerances and assembly clearances, the center line of the tooth peak of one first rack is difficult to completely coincide with the center line of the tooth valley of the second rack when it is inserted between two adjacent second racks. Even a slight circumferential offset (possibly due to minor circumferential rotation of the drive sleeve relative to the drive linkage or tooth profile error), while not affecting the macroscopic engagement, will cause misaligned contact and collision between the engagement slopes of the first and second racks.

[0069] This misaligned contact generates a tangential force that causes an uncontrollable, minute rotation (typically ±0.5°) in the circumferential direction of the drive linkage. This results in a deviation in the final displacement of the medication stopper. For high-precision dosing pens (especially insulin pens), such micrometer-level displacement deviations are sufficient to cause fluctuations in the injection dose, resulting in a discrepancy between the actual and set doses, severely affecting dosing accuracy and potentially posing risks to patient medication safety.

[0070] Therefore, how to solve the circumferential rotation of the drive linkage caused by the misalignment of the rack meshing is a technical problem that urgently needs to be solved in this field.

[0071] The defects in the above solutions and the reasons for their occurrence are the results of the inventors' practice and careful research. Therefore, the discovery process of the above problems and the solutions proposed in this disclosure should be considered as the inventors' contributions to this disclosure.

[0072] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0073] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0074] like Figure 1 As shown, in the prior art, a drive sleeve 1 is rotatably disposed inside the pen body 6, and a plurality of first racks 41 are evenly distributed circumferentially on the inner wall of the drive sleeve 1; a drive connecting rod 2 is rotatably disposed inside the drive sleeve 1, and at least two second racks 5 are disposed on the outer wall of the drive connecting rod 2; when the drive sleeve 1 moves toward the second racks 5, the first racks 41 mesh with the second racks 5; Figure 1In the diagram, 'a' represents the centerline of the first rack 41, and 'b' represents the centerline of the second rack 5. When the drive sleeve 1 moves towards the second rack 5, that is, when the centerlines 'a' and 'b' are completely aligned axially, and the first rack 41 is inserted between the two second racks 5 to form a meshing relationship, the drive link 2 will not experience a slight circumferential offset. However, during dosage adjustment, the drive sleeve 1 will rotate circumferentially relative to the drive link 2. If the centerline of the first rack 41 is aligned with the centerline of the second rack 5... Figure 1 At position a1 or a2, where the centerline of the first rack 41 is offset from the centerline of the second rack 5, when the first rack 41 is inserted between two adjacent second racks 5, the meshing inclined surfaces of the first rack 41 and the second rack 5 will make non-aligned contact collisions. This non-aligned contact will generate a tangential component force, which will cause the drive linkage 2 to rotate uncontrollably in the circumferential direction. This results in a deviation in the final displacement of the liquid stopper.

[0075] like Figure 2 and Figure 9 As shown, at least one embodiment provides an activation clutch structure, comprising: a drive sleeve 1, which is rotatably disposed within the pen body 6, and has a plurality of key tooth groups 4 evenly distributed circumferentially on its inner wall; the key tooth groups 4 extend axially along the drive sleeve 1, and their length is greater than the axial movement stroke of the drive sleeve 1. A drive connecting rod 2, which is rotatably located within the drive sleeve 1, and has at least two second racks 5 circumferentially disposed on its outer wall; when the drive sleeve 1 moves axially toward the second racks 5, the key tooth groups 4 mesh with the second racks 5, and the drive sleeve 1 can drive the drive connecting rod 2 to rotate synchronously. A limiting ring 3, which is rotatably sleeved on the outer wall of the drive connecting rod 2, and has a plurality of limiting notches 30 circumferentially opened on its outer wall; one limiting notch 30 accommodates and limits one key tooth group 4, and limits the expansion of the key tooth group 4; the limiting ring 3 serves to limit each key tooth group 4, so that during the dosage adjustment stage, it limits the key tooth groups 4 from both sides, preventing them from expanding to both sides under the action of elasticity. During dose adjustment, the drive sleeve 1 rotates relative to the drive link 2, and the key tooth assembly 4 drives the limiting ring 3 to rotate synchronously. At this time, each key tooth assembly 4 is limited by the limiting ring 3, and its horizontal projected area is consistent with the horizontal projected area of ​​the limiting notch 30, and both are smaller than the horizontal projected area of ​​the tooth gap between the two second racks 5. During excitation, the drive sleeve 1 moves axially relative to the drive link 2, and the key tooth assembly 4 moves relative to the limiting ring 3 and inserts into the tooth gap between the two second racks 5. After the key tooth assembly 4 is disengaged from the limiting notch 30, the two side walls of the key tooth assembly 4 respectively fit against the side walls of the two second racks 5. Through the cooperation of the key tooth assembly 4, the second racks 5, and the limiting ring 3, in the initial stage of excitation, the limiting ring 3 limits the key tooth assembly 4, avoiding misaligned contact collisions of the meshing inclined surfaces during the meshing of the first key tooth with the two second racks 5. This eliminates the slight axial displacement caused by the slight circumferential rotation or tooth profile error of the drive link 2, ensuring the stability of the dose injection.

[0076] Reference Appendix Figure 4 The limiting notch 30 is V-shaped, and the horizontal projected area of ​​the opening of the limiting notch 30 is smaller than the horizontal projected area of ​​the tooth gap between the two second racks 5. Figure 4 In this context, angle B represents the opening angle of the limiting notch 30 in the horizontal direction; angle A represents the opening angle of the tooth gap between two adjacent second racks 5, and angle B is smaller than angle A. This ensures that when the two first racks 41, limited by the limiting notch 30, are initially inserted into the tooth gap between the two adjacent second racks 5, even if the centerline of the key tooth group 4 deviates from the centerline of the second rack 5, they will exhibit the following characteristics: Figure 1 In state a1 or a2, the meshing inclined surface of the key tooth group 4 and the meshing inclined surface of the second rack 5 will not collide due to misalignment; thus preventing uncontrollable micro-rotation of the drive linkage 2 in the circumferential direction. This improves the accuracy of the rotation of the drive linkage 2 and ensures the stability of the dosage injection.

[0077] Reference Appendix Figure 6 The key tooth assembly 4 is elastic. When the key tooth assembly 4 is disengaged from the limiting notch 30, it is adapted to deform towards the two adjacent second racks 5. The key tooth assembly 4 includes two symmetrically arranged first racks 41. The horizontal projection of the first racks 41 is triangular, and there is a gap between the two first racks 41. One corner of the first rack 41 faces the axis of the drive sleeve 1. Furthermore, the bottom edge of the first rack 41 is fixed to the inner wall of the drive sleeve 1. When the two first racks 41 are limited by the limiting notch 30, their horizontal projection area is smaller than the horizontal projection area of ​​the tooth gap between the two second racks 5.

[0078] Reference Appendix Figure 6 An expansion groove 42 is formed on the outer wall of the first rack 41, and the axial length of the expansion groove 42 is greater than the axial thickness of the limiting ring 3. When the driving sleeve 1 moves axially relative to the driving connecting rod 2, the expansion groove 42 is adapted to abut against the side wall of the limiting notch 30, so that the side walls of the two first racks 41 abut against the side walls of the two second racks 5 respectively. An inclined surface 43 is provided on the side wall of the expansion groove 42 near the second rack 5, and the inclined surface 43 is adapted to guide the side wall of the limiting notch 30 into the expansion groove 42.

[0079] Reference Appendix Figure 7 When the two side walls of the limiting notch 30 are not inserted into the expansion groove 42, the horizontal projection angle of the two first racks 41 is B. (See attached diagram) Figure 8 When the drive sleeve 1 moves axially towards the second rack 5 until the two side walls of the limiting notch 30 are inserted into the expansion groove 42, the horizontal projection angle of the two first racks 41 is A. And angle B is less than angle A. Figure 7F1 in the equation represents the force applied to the first rack 41 when the drive sleeve 1 moves axially toward the second rack 5.

[0080] Reference Appendix Figure 4 and Figure 9 At least one elastic tooth 20 is provided on the outer wall of the end of the drive link 2 away from the drive sleeve 1; several sound-producing teeth 60 are evenly distributed around the inner wall of the pen body 6, and the elastic tooth 20 meshes with the sound-producing teeth 60; wherein, after the key tooth group 4 meshes with the second rack 5, the coil spring 83 is adapted to drive the drive sleeve 1 and the drive link 2 to rotate, and the elastic tooth 20 abuts against the sound-producing teeth 60 in sequence to produce sound.

[0081] Reference Appendix Figure 7 and Figure 8 The working principle of the clutch mechanism is as follows:

[0082] During dosage adjustment, when the drive sleeve 1 rotates circumferentially, the limiting ring 3 is driven to rotate synchronously relative to the drive connecting rod 2 through each key tooth group 4;

[0083] During activation, the drive sleeve 1 moves axially, and the drive sleeve 1 drives the key tooth group 4 to move axially synchronously, and each first rack 41 moves axially relative to the limiting ring 3.

[0084] like Figure 7 As shown, when the key tooth assembly 4 is initially inserted into the tooth gap between two adjacent second tooth racks 5, the two first tooth racks 41 are still limited by the limiting notch 30, even if the center line of the key tooth assembly 4 is offset from the center line of the second tooth rack 5 (i.e., exhibiting the following characteristics). Figure 1 (In state a1 or a2), the meshing inclined surface of the key tooth group 4 and the meshing inclined surface of the second rack 5 will not have misaligned contact collision.

[0085] like Figure 8 As shown, as the drive sleeve 1 continues to move towards the second rack 5, when the first rack 41 moves to the point where the two side walls of the limiting notch 30 are respectively inserted into the corresponding expansion grooves 42, the first rack 41 expands circumferentially to both sides under its own elastic force. At this time, the horizontal projection angle between the two first racks 41 increases, and the two outer walls of the first rack 41 abut against the side walls of the second rack 5, thereby improving the stability of the meshing between the first rack 41 and the second rack 5. When the key tooth group 4 is initially inserted into the two second racks 5, the key tooth group 4 is limited by the limiting notch 30 and will not expand outward to increase the angle, so as to reduce the non-aligned contact collision with the second rack 5 when it initially contacts it; and when the key tooth group 4 and the second rack 5 form a meshing relationship, the key tooth group 4 expands outward to improve the stability of the meshing. This prevents the phenomenon of uncontrollable micro-rotation of the drive linkage 2 in the circumferential direction. It improves the accuracy of the rotation of the drive linkage 2 and ensures the stability of the dosage injection.

[0086] Reference Appendix Figure 9 At least one embodiment provides an injection pen, including: a dosage knob 7, which is rotatably disposed at one end of the pen body 6; the dosage knob 7 is adapted to rotate in both directions relative to the pen body 6 to achieve the effect of adjusting the dosage in both directions. (See attached document) Figure 10 A coil spring bracket 8 is disposed inside the pen body 6, and a coil spring 83 is disposed inside it. The coil spring bracket 8 is fixed inside the pen body 6. An inner core frame 80 is rotatably disposed inside the coil spring bracket 8, and the inner end of the coil spring 83 is fixed to the outer wall of the inner core frame 80. The two ends of the coil spring 83 are respectively fixed to the coil spring bracket 8 and the inner core frame 80 to limit and fix the two ends of the coil spring 83. A protrusion 81 is axially provided on the inner wall of the inner core frame 80, and a sliding groove 90 adapted to the protrusion 81 is axially opened on the outer wall of the clutch rod 9. When the clutch rod 9 rotates, it pushes the inner core frame 80 to rotate synchronously through the protrusion 81. When activated, the clutch rod 9 moves axially relative to the inner core frame 80 to drive the drive sleeve 1 to move axially synchronously. The engagement of the protrusion 81 and the groove 90 allows the clutch lever 9 to drive the inner core frame 80 to rotate circumferentially relative to the coil spring support 8. When the clutch lever 9 moves axially, the protrusion 81 can move within the groove 90 to prevent the inner core frame 80 from moving relative to the coil spring support 8. The clutch lever 9 is rotatably mounted within the coil spring support 8, with one end fixed to the end of the drive sleeve 1 and engaging with the dosage knob 7. During dosage adjustment, the dosage knob 7 drives the clutch lever 9 to rotate, which in turn drives the drive sleeve 1 to rotate synchronously, thus compressing the coil spring 83. A return spring 10 is installed inside the drive sleeve 1, sleeved on the outer wall of the drive connecting rod 2, with one end fixed to the fixed platform 21 on the outer wall of the drive connecting rod 2. After excitation, the return spring 10 pushes the drive sleeve 1, causing it to move towards the dosage knob 7, thereby disengaging the first rack 41 from the second rack 5. The inclined surface 43 of the sidewall of the expansion groove 42 allows the sidewall of the limiting notch 30 to smoothly detach from the expansion groove 42.

[0087] Reference Appendix Figure 10 In order to improve the stability of the coil spring 83, a limiting plate 82 is provided at the end of the inner core frame 80 away from the coil spring bracket 8. The outer diameter of the limiting plate 82 is smaller than the inner diameter of the coil spring bracket 8, and the limiting plate 82 is suitable for limiting the axial movement of the coil spring 83.

[0088] In the description of the embodiments of the present invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention based on the specific circumstances.

[0089] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence unless expressly indicated herein. Therefore, without departing from the teachings of the exemplary embodiments, the first element, component, region, layer, or segment discussed above may be referred to as a second element, component, region, layer, or segment.

[0090] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. An excitation clutch structure, characterized in that, include: The drive sleeve (1) is rotated inside the pen body (6), and several key teeth (4) are evenly distributed on the inner wall. The drive link (2) rotates within the drive sleeve (1), and at least two second racks (5) are provided on the outer wall circumferentially. The limiting ring (3) is rotatably sleeved on the outer wall of the drive connecting rod (2), and several limiting notches (30) are opened in the circumferential direction of the outer wall. A limiting notch (30) accommodates and limits a key tooth assembly (4); During dose adjustment, the drive sleeve (1) rotates relative to the drive connecting rod (2) so that the key tooth assembly (4) drives the limiting ring (3) to rotate synchronously. When activated, the drive sleeve (1) moves axially relative to the drive connecting rod (2) so that the key tooth assembly (4) moves axially relative to the limiting ring (3) and is inserted into the tooth gap of the two second racks (5); After the key tooth assembly (4) is released from the limiting notch (30), the two side walls of the key tooth assembly (4) are respectively attached to the side walls of the two second toothed racks (5); The limiting notch (30) is V-shaped, and the horizontal projected area of ​​the opening of the limiting notch (30) is smaller than the horizontal projected area of ​​the tooth gap between the two second racks (5). The key tooth assembly (4) is elastic. When the key tooth assembly (4) is disengaged from the limiting notch (30), the key tooth assembly (4) is adapted to deform in the direction of approaching the two adjacent second toothed racks (5).

2. The excitation and disengagement structure as described in claim 1, characterized in that, The key tooth assembly (4) includes two symmetrically arranged first toothed racks (41), the first toothed racks (41) are triangular in horizontal projection, and there is a gap between the two first toothed racks (41); When the two first racks (41) are limited by the limiting notch (30), the horizontal projected area of ​​the two first racks (41) is smaller than the horizontal projected area of ​​the tooth gap between the two second racks (5).

3. The excitation and disengagement structure as described in claim 2, characterized in that, An expansion groove (42) is formed on the outer wall of the first rack (41), and the axial length of the expansion groove (42) is greater than the axial thickness of the limiting ring (3); In this process, the drive sleeve (1) moves axially relative to the drive connecting rod (2), and the expansion groove (42) is adapted to abut against the side wall of the limiting notch (30) so that the side walls of the two first racks (41) abut against the side walls of the two second racks (5) respectively.

4. The excitation and disengagement structure as described in claim 3, characterized in that, An inclined surface (43) is provided on one side wall of the expansion groove (42) near the second rack (5), and the inclined surface (43) is adapted to guide the side wall of the limiting notch (30) to be inserted into the expansion groove (42).

5. The excitation and disengagement structure as described in claim 1, characterized in that, At least one elastic tooth (20) is provided on the outer wall of the end of the drive link (2) away from the drive sleeve (1); The inner wall of the pen body (6) is evenly distributed with a plurality of sound-producing teeth (60), and the elastic teeth (20) mesh with the sound-producing teeth (60); When the key tooth group (4) meshes with the second rack (5), the coil spring (83) is adapted to drive the drive sleeve (1) and the drive connecting rod (2) to rotate, and the elastic tooth (20) abuts against the sound-producing tooth (60) in sequence to produce sound.

6. An injection pen, characterized in that, The excitation clutch structure as described in any one of claims 1-5 includes: The dosage knob (7) is located at one end of the pen body (6); A spring support (8) is set inside the pen body (6), and a spring (83) is installed inside it. The clutch lever (9) is rotatably mounted inside the coil spring bracket (8), with one end fixed to the end of the drive sleeve (1) and engaging with the dosage knob (7); During dose adjustment, the dose knob (7) drives the clutch lever (9) to rotate, and the clutch lever (9) drives the drive sleeve (1) to rotate synchronously to pressurize the coil spring (83).

7. The injection pen as described in claim 6, characterized in that, A reset spring (10) is provided inside the drive sleeve (1). The reset spring (10) is sleeved on the outer wall of the drive connecting rod (2), and one end of the reset spring (10) is fixed on the fixed platform (21) on the outer wall of the drive connecting rod (2).

8. The injection pen as described in claim 7, characterized in that, An inner core frame (80) is rotatably disposed inside the coil spring bracket (8), and the inner end of the coil spring (83) is fixed to the outer wall of the inner core frame (80). The inner core frame (80) has a convex strip (81) axially arranged on its inner wall, and the clutch rod (9) has a sliding groove (90) axially arranged on its outer wall to match the convex strip (81). When the clutch lever (9) rotates, it pushes the inner core frame (80) to rotate synchronously through the protrusion (81); When activated, the clutch lever (9) moves axially relative to the inner core frame (80) to drive the drive sleeve (1) to move axially synchronously.

9. The injection pen as described in claim 8, characterized in that, A limiting plate (82) is provided at one end of the inner core frame (80) away from the coil spring bracket (8). The outer diameter of the limiting plate (82) is smaller than the inner diameter of the coil spring bracket (8). The limiting plate (82) is adapted to limit the axial movement of the coil spring (83).

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