An injection pen

Abstract

The present application relates to a kind of injection pen, comprising: barrel shell, drug storage device, delivery system and clutch block, drug storage device is detachably connected with shell, it can be switched between the injection state fixed in shell, and the drug change state with shell unfixing.Fixed in the injection state, drug storage device and shell are connected, and the drug change state with shell unfixing, drug storage device and shell are disconnected.The delivery system includes piston rod and drive assembly, drive assembly is composed of driving piece and guide piece, guide piece is rotatably assembled in shell, one of driving piece and guide piece is slidably connected with piston rod and can be relatively slid along the first direction of the length direction of shell, the other is threadedly connected with piston rod and can be relatively rotated along the second circumferential direction perpendicular to the first direction, to cooperate and realize drug delivery drive.The clutch block is movably arranged in the interior of shell, and can be switched between coupling position and decoupling position.Drug storage device is switched to the injection state, clutch block moves to the coupling position and stops rotation of guide piece, so that driving piece can drive piston rod to move downward by rotation, and stable injection operation is completed;When drug storage device is switched to the drug change state, clutch block moves to decoupling position and is separated from guide piece, and the rotation restriction of guide piece is removed, so that piston rod can be moved upward to reset under the action of external force.The present application realizes the independent distinction of injection state and drug change state by the adaptive switching of clutch block relative to guide piece, so that piston rod can be reset in the drug change state, and the problem of repeated use of injection pen is solved.

Description

Technical Field

[0001] This invention belongs to the field of medical infusion device technology, specifically relating to an injection pen. Background Technology

[0002] Injection pens, as portable medical devices enabling micro- and quantitative subcutaneous drug delivery, are widely used in long-term chronic disease and precision drug delivery scenarios such as diabetes, growth hormone intervention, and postoperative analgesia. However, current injection pens are limited by the self-locking characteristic of their threaded joints, preventing the piston rod from returning to its original position after a single injection. This results in single-use pens, leading to significant waste and increased costs. In reality, the mechanical structure of an injection pen is generally not contaminated by the injection process and can therefore be reused. For subsequent uses, only the drug reservoir, especially the vial and needle, needs to be replaced, and the piston rod needs to be reset. The replaced drug reservoir and the reset piston rod are then reassembled for the next injection.

[0003] Therefore, there is an urgent need to propose a novel injection pen structure to solve the technical problems of the piston rod not being able to reset and the lack of replacement of the drug storage part, which leads to increased usage costs and wasted resources. Summary of the Invention

[0004] The purpose of this invention is to overcome the defects of the prior art and provide an injection pen that solves the technical problems of the piston rod not being able to reset and the drug storage part not being replaceable in existing injection pens, so as to realize the reusability of the mechanical structure of the injection pen, thereby reducing the cost of use and saving resources.

[0005] The present invention provides an injection pen, comprising:

[0006] case; The drug storage device is detachably connected to the housing and has an injection state fixed to the housing and a drug replacement state unfixed to the housing; A delivery system includes a piston rod for delivering a drug within the drug storage device and a drive assembly for driving the piston rod. The drive assembly includes a drive member and a guide member. The guide member is rotatably disposed on the housing. One of the drive member and the guide member is slidably connected to the piston rod and is slidable relative to the piston rod in a first direction. The other is threadedly connected to the piston rod and is rotatable relative to the piston rod in a second direction. A clutch block, movably disposed in the housing, has a coupled position that restricts the rotation of the guide member and a decoupled position that releases the restriction on the rotation of the guide member. When the drug storage device is switched to the injection state, the clutch block moves to the coupled position to stop the rotation of the guide member, allowing the drive member to rotate and drive the piston rod downward to inject the drug in the drug storage device. When the drug storage device is switched to the medication replacement state, the clutch block can move to the decoupled position to disengage from the guide member, allowing the piston rod to be driven upward by an external force to reset. The shell is formed into a cylindrical shape, the first direction is along the length of the shell, and the second direction is the circumferential direction in a plane perpendicular to the first direction.

[0007] In some embodiments, when the clutch block moves to the coupling position, the clutch block and the guide member engage with each other through anti-rotation grooves and anti-rotation ribs extending along the first direction to prevent the guide member from rotating.

[0008] In some embodiments, both the anti-rotation groove and the anti-rotation rib include a plurality of corresponding ones, one of which is distributed on the outside of the guide member and the other is distributed on the inside of the clutch block.

[0009] In some embodiments, the anti-rotation rib has a first inclined surface near one end of the anti-rotation groove, and the groove wall of the anti-rotation groove has a second inclined surface corresponding to the first inclined surface near one end of the anti-rotation rib. When the clutch block moves to the coupling position, the first inclined surface and the second inclined surface slide together to guide the anti-rotation rib into the anti-rotation groove.

[0010] In some embodiments, the housing is provided with a sliding groove extending along the first direction, and the clutch block is provided with a sliding rib corresponding to the sliding groove on its outer side, and the sliding groove and the sliding rib slide in engagement.

[0011] In some embodiments, an elastic element is also included between the housing and the clutch block. When the drug storage device switches from the injection state to the drug changing state, the elastic element pushes the clutch block to slide from the coupling position to the decoupling position.

[0012] In some embodiments, the elastic element is a spring, the housing is provided with a positioning ring, the clutch block is provided with a positioning groove, and the two ends of the spring are respectively sleeved on the positioning ring and in the positioning groove.

[0013] In some embodiments, the sliding rib is provided on the outer wall of the positioning groove, and when the clutch block is provided with an anti-rotation groove or an anti-rotation rib, the anti-rotation groove or the anti-rotation rib is provided on the inner wall of the positioning groove.

[0014] In some embodiments, the housing has a recess extending along the first direction inside, and a slider is provided on the outside of the clutch block and slidably disposed in the recess.

[0015] In some embodiments, the slider is provided with a third inclined surface extending along the first direction, the groove is formed on a protrusion on the inner side of the housing, and the protrusion is provided with a fourth inclined surface at the lower end of the groove that slides in cooperation with the third inclined surface.

[0016] In some embodiments, the fourth inclined surface is provided on the protrusion at the lower end of the protrusion, and an annular rib is provided on the outer side of the clutch block. The annular rib is provided with a break that matches the protrusion. When the clutch block is in the coupling position, the protrusion is located inside the break.

[0017] In some embodiments, the upper part of the drug storage device is provided with a locking block, and the lower part of the housing is provided with a locking groove. The locking block cooperates with the locking groove. The locking groove includes an inlet section extending along the first direction and a locking section extending along the second direction. When the drug storage device switches from the drug changing state to the injection state, the locking block enters the locking section from the inlet section to fix the drug storage device to the housing to form the injection state.

[0018] In some embodiments, a locking groove and a locking protrusion extending along the first direction are provided between the drug storage device and the clutch block. One of the locking groove and the locking protrusion is located on the upper part of the drug storage device, and the other is located on the lower part of the clutch block. When the drug storage device is in the injection state, the locking protrusion enters the locking groove, thereby restricting the rotation of the drug storage device relative to the housing when the drug storage device is in the injection state.

[0019] In some embodiments, an elastic element is included. The drug storage device includes a drug reservoir and a drug bottle installed in the drug reservoir. The drug reservoir is formed into a cylindrical shape with an open top. When the drug storage device is in the injection state, the elastic element presses the clutch block downward, so that the clutch block abuts against the upper end of the drug bottle, thereby locking the drug bottle in the drug reservoir along the first direction.

[0020] In some embodiments, the housing includes an outer shell and a mounting base, the clutch block is movably connected to the mounting base, the outer shell has a mounting surface extending perpendicular to the first direction, the mounting surface has mounting holes, the mounting base and the drive member are respectively disposed on both sides of the mounting surface and connected by a snap-fit ​​structure passing through the mounting holes.

[0021] The injection pen provided by this invention has at least the following beneficial effects: (1) A clutch-type position linkage switching mechanism is set up. By coupling the clutch block relative to the guide and adaptively switching the structural position, the injection state and the medication change state can be independently distinguished. In the injection state, the guide is stopped from rotating, ensuring the stable operation of the piston rod feed and preventing the transmission components from rotating or deviating, thereby ensuring injection accuracy. In the medication change state, the stop on the rotation of the guide is released, and the piston rod can be manually reset, thus solving the problem that the transmission injection pen cannot reset the piston rod, which leads to the inability to reuse it.

[0022] (2) In order to meet the needs of drug refilling, the drug storage device is detachably connected to the shell, so that the drug storage device or the drug bottle in the drug storage device can be replaced separately, ensuring that the rest of the injection pen can be reused, saving usage costs and reducing resource waste.

[0023] (3) The combination structure of multiple sets of evenly distributed anti-rotation grooves and anti-rotation ribs, combined with the alignment structure of the first inclined surface and the second inclined surface, realizes the precise insertion and stable positioning of the clutch block. The anti-rotation force is uniform, the structural wear is small, the fitting accuracy is high, and the stability and service life of long-term operation are guaranteed.

[0024] (4) The integrated guide limit and locking structure forms a guide track for the clutch block through the sliding groove and sliding rib, the sink groove and the slider. The elastic element presses the locking block on the locking groove, the clutch block presses the medicine bottle, the anti-rotation groove and anti-rotation rib prevent circumferential rotation, and the protrusion and the break prevent circumferential rotation. This achieves multiple constraints and locking of the medicine storage device to prevent rotation and detachment, and to prevent the medicine bottle from shaking. This avoids problems such as loosening and movement of the medicine storage structure, so as to ensure the stability of the injection pen and meet the needs of high-precision injection.

[0025] (5) By separating the outer shell and the mounting base, and setting the mounting base and the drive unit on the two sides of the mounting surface, the manufacturing difficulty caused by setting a lot of complex structures in a single shell is avoided. In particular, the relevant structures in the shell do not overlap along the length of the shell, which makes it easy to demold during the injection molding process of the shell. Attached Figure Description

[0026] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art 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.

[0027] Figure 1 This is an overall schematic diagram of the injection pen in some embodiments of the present invention; Figure 2This is a cross-sectional schematic diagram of the injection pen in some embodiments of the present invention; Figure 3 This is an exploded view of the injection pen in some embodiments of the present invention; Figure 4 This is a schematic diagram of the clutch block in some embodiments of the present invention; Figure 5 This is a schematic diagram of a guide component in some embodiments of the present invention; Figure 6 This is a schematic cross-sectional view of the housing in some embodiments of the present invention; Figure 7 This is an exploded view of the shell in some embodiments of the present invention; Figure 8 This is an exploded view of the drug storage device in some embodiments of the present invention; Figure 9 This is a schematic diagram of the outer casing in some embodiments of the present invention; Figure 10 This is a cross-sectional schematic diagram of the outer casing in some embodiments of the present invention; Figure 11 This is a schematic diagram of the mounting base in some embodiments of the present invention; Figure 12 This is an exploded view of the driving component in some embodiments of the present invention.

[0028] Explanation of reference numerals in the attached figures: 1. Housing; 11. Outer shell; 111. Mounting surface; 1111. Mounting hole; 112. Receiving groove; 113. Guide rib; 114. Display window; 12. Mounting base; 121. Sliding groove; 122. Positioning ring; 123. Countersunk groove; 124. Protrusion; 1241. Fourth inclined surface; 1242. Protrusion; 125. Locking groove; 1251. Inlet section; 1252. Locking section; 126. Extending arm; 127. Hook hole; 128. Annular positioning rib; 129. Perforation; 2. Drug storage device; 21. Drug compartment; 211. Locking block; 212. Snap-fit ​​groove; 2121. Side wall; 22. Drug bottle; 23. Injection needle; 24. Piston; 3. Delivery system; 31. Piston rod; 32. Drive component; 321. Hook; 322. Guide groove; 323. Fixing screw; 324. Drive rod; 33. Guide component; 331. Anti-rotation rib; 3311. First inclined surface; 332. Positioning end; 3321. Rotating section; 3322. Positioning section; 34. Button; 35. Scale rod; 36. Transmission rod; 4. Clutch block; 41. Anti-rotation groove; 411. Second inclined surface; 42. Sliding rib; 43. Positioning groove; 44. Slider; 441. Third inclined surface; 45. Annular rib; 451. Break; 46. Snap-fit ​​protrusion; 461. Side surface; 5. Elastic components. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some 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.

[0030] In the description of this invention, it should be noted that the terms "first direction," "second direction," "axial direction," "circumferential direction," "center," "upper," "lower," "left," "right," "vertical," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for 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. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0031] In the description of this invention, it should be noted that "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural.

[0032] In the description of this invention, it should be noted that the term "layer" refers to a portion of material comprising a region having a certain thickness. A layer may extend over the entire lower or upper structure, or may have a extent smaller than that of the lower or upper structure. Furthermore, a layer may be a region of a homogeneous or heterogeneous continuous structure, with a thickness less than the thickness of the continuous structure. For example, a layer may be located between the top and bottom surfaces of a continuous structure, or between any pair of horizontal planes therebetween. A layer may extend horizontally, vertically, and / or along a conical surface.

[0033] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0034] Embodiments of the present invention will now be described with reference to the accompanying drawings.

[0035] This invention discloses an injection pen, such as Figures 1 to 3As shown, it includes a cylindrical shell 1, a drug storage device 2, a delivery system 3, and a clutch block 4. Hereinafter, the length direction of the shell 1 is defined as the first direction, and the circumferential direction in the plane perpendicular to the first direction, that is, the circumferential direction of the shell 1, is defined as the second direction. The drug storage device 2 contains drugs or has a drug delivery system that introduces drugs into the drug storage device 2. Its lower end is generally an injection needle 23, and its upper part is equipped with a piston 24. When the piston 24 is driven to move downward, the drugs are discharged from the drug storage device 2 through the injection needle 23. Subsequently, the drug bottle 22 in the drug storage device 2 can be replaced or the drugs in the drug storage device 2 can be re-injected through the delivery system. The upper part of the drug storage device 2 is detachably connected to the lower part of the housing 1, thereby forming a space in the internal space of the two that can accommodate drugs, delivery system 3, clutch block 4 and other related structures. When the drug storage device 2 is fixed to the housing 1, the entire injection pen structure is stably connected, forming an injection state in which drugs can be injected into the drug storage device 2. When it is de-fixed from the housing 1, the related structures can be reset and the drugs in the drug storage device 2 can be replaced or re-injected, forming a drug replacement state.

[0036] like Figure 2As shown, the delivery system 3 includes a piston rod 31 for delivering medication into the drug storage device 2 and a drive assembly for driving the piston rod 31. The piston rod 31 passes through the housing 1 and extends downward into the drug storage device 2. When the piston rod 31 is driven downward by the drive assembly, it can push the medication in the drug storage device 2 for injection. The drive assembly includes a drive member 32 and a guide member 33. Under the action of external force, the drive member 32 provides a driving force for the piston rod 31 to move downward, while the guide member 33 provides a guiding function for the movement of the piston rod 31. To enable the piston rod 31 to move downwards, the drive member 32 is mounted inside the housing 1 in a unidirectional rotation manner. It is threadedly connected to the piston rod 31, meaning it can rotate relative to the piston rod 31 in a second direction. At this time, the threaded connection between the drive member 32 and the piston rod 31 is located at the lower part of the piston rod 31. When the drive member 32 rotates, its position relative to the housing 1 in the first direction remains fixed. Therefore, the piston rod 31 can move downwards relative to the drive member 32 without rotating with it, thus achieving feed. Since the piston rod 31 is generally a slender cylindrical structure, a guide member 33 is used to ensure the stability of its feed. The piston rod 31 is connected to the piston rod 31 in a sliding manner along the first direction, thereby ensuring that it does not shake during the feeding process. When the drive member 32 rotates in one direction, it presses the piston rod 31 downward through the threaded connection to inject the drug in the drug storage device 2, that is, the injection state. When the injection is completed, the threaded connection between the drive member 32 and the piston rod 31 is located at the upper part of the piston rod 31, while the guide member 33 remains fixed relative to the housing 1 during this process. Therefore, on the one hand, it restricts the piston rod 31 from rotating and prevents the piston rod 31 from rotating with the rotation of the drive member 32, and on the other hand, it guides the feeding of the piston rod 31 along the first direction.

[0037] In order for the piston rod 31 to return to its original position in the first direction during the medication change, that is, for its threaded connection with the drive member 32 to move from the upper part to the lower part of the piston rod 31 in preparation for the next injection, the piston rod 31 needs to be able to rotate relative to the housing 1. This requires releasing the anti-rotation mechanism of the guide member 33 on the piston rod 31. Figure 2As shown, this embodiment also includes a clutch block 4 movably mounted on the housing 1. The clutch block 4 has a decoupling position and a coupling position on the housing 1. In the coupling position, the clutch block 4 controls the guide 33 to stop rotation, thereby preventing the piston rod 31 from rotating, ensuring the injection stability and accuracy of the piston rod 31. In the decoupling position, the clutch block 4 no longer prevents the guide 33 from rotating, and the piston rod 31 can rotate relative to the housing 1, thereby rotating relative to the drive 32, causing its threaded connection with the drive 32 to move from its upper part to its lower part, thus completing the reset. This method controls the rotation of the guide 33 by switching the position of the clutch block 4 relative to the guide 33 in the injection state and the medication change state, allowing the piston rod 31 to move upward or downward in the first direction in both states to achieve different functions. This ensures that the piston rod 31 can be reset while clearly distinguishing between the two states, guaranteeing the rational allocation of the entire injection pen's functions.

[0038] Obviously, in the above embodiments, the movement of the piston rod 31 relative to the driving member 32 and the guide member 33 is related, that is, the driving member 32 rotates relative to the piston rod 31, and the guide member 33 controls the piston rod 31 to only feed in the first direction. By swapping the functions of the drive member 32 and the guide member 33, the above functions can still be achieved. That is, the drive member 32 and the piston rod 31 are connected in a sliding manner along the first direction, while the guide member 33 and the piston rod 31 are connected in a threaded manner. When the unidirectional rotation of the drive member 32 drives the piston rod 31 to rotate, since the guide member 33 is threadedly connected to the piston rod 31 and the guide member 33 is controlled by the clutch block 4 to remain fixed, the piston rod 31 can rotate relative to the guide member 33. During the rotation, it achieves feeding in the first direction, thereby injecting the drug in the drug storage device 2. When the piston rod 31 needs to be reset, the clutch block 4 releases the anti-rotation of the guide member 33, and the piston rod 31 is pushed in the first direction in the opposite direction to the feeding direction. Then the piston rod 31 can rotate relative to the guide member 33, thereby moving the threaded connection position of the piston rod 31 and the guide member 33 from the upper part to the lower part of the piston rod 31, realizing the reset of the piston rod 31.

[0039] Furthermore, when the clutch block 4 is in the coupling position, the clutch block 4 is sleeved on the outside of the guide member 33, and the two form an axial anti-rotation fit through the anti-rotation groove 41 and the anti-rotation rib 331 extending along the first direction. Specifically, as shown... Figure 4 , Figure 5As shown, the anti-rotation groove 41 is formed on the inner wall of the clutch block 4 facing the guide member 33, and the anti-rotation rib 331 is correspondingly protruding on the outer wall of the guide member 33. On the one hand, in the injection state, the clutch block 4 is in the coupling position, and the groove wall of the anti-rotation groove 41 abuts against the side wall of the anti-rotation rib 331, which can form a limiting constraint on the guide member 33 in the second direction, keeping the guide member 33 in a fixed and stationary state. At this time, the guide member 33 plays a role in anti-rotation limiting and axial guidance for the piston rod 31, preventing the piston rod 31 from rotating relative to the housing 1 when the drive member 32 rotates, ensuring that the piston rod 31 can only be stably fed downward in the first direction, thereby To avoid problems such as feed deviation and inaccurate dosage caused by the rotation of the guide member 33, the stability and injection accuracy during the injection process are ensured. On the other hand, since both the anti-rotation groove 41 and the anti-rotation rib 331 extend along the first direction, when the drug storage device 2 switches from the injection state to the injection state, the clutch block 4 slides from the decoupled position to the coupled position to form a guide, thereby ensuring that the position switching of the clutch block 4 is smooth and accurate until the anti-rotation groove 41 and the anti-rotation rib 331 disengage from each other, releasing the anti-rotation limit on the guide member 33. The guide member 33 then returns to a state where it can rotate relative to the housing 1, and the piston rod 31 can cooperate to complete the reset action, realizing the state switching of the injection pen. Obviously, in the above embodiment, the positions of the anti-rotation groove 41 and the anti-rotation rib 331 are interchanged, that is, the anti-rotation groove 41 is set on the outer wall surface of the guide member 33, and the anti-rotation rib 331 is set on the inner wall surface of the clutch block 4, which can also achieve the above effect.

[0040] Specifically, such as Figure 4 , Figure 5 As shown, both the anti-rotation groove 41 and the anti-rotation rib 331 are configured as multiple sets of corresponding structures. That is, multiple sets of anti-rotation ribs 331 are evenly distributed along the second direction on the outer wall of the guide member 33, and multiple sets of anti-rotation grooves 41 are evenly distributed along the second direction on the inner wall of the clutch block 4. Each set of anti-rotation grooves 41 corresponds one-to-one with the anti-rotation rib 331. When the clutch block 4 moves to the coupling position, all the anti-rotation ribs 331 are simultaneously engaged in the corresponding anti-rotation grooves 41. This configuration allows the guide member 33 to be subjected to more uniform force in the second direction, avoiding local stress concentration, improving the anti-rotation effect and service life, and preventing the guide member 33 from shifting relative to the first direction when anti-rotation is performed on one side, thereby better ensuring the stability of the piston rod 31's posture during feeding.

[0041] Furthermore, since the guide member 33 is rotatably connected relative to the housing 1, it may rotate during medication changes or product assembly, causing misalignment between the anti-rotation rib 331 and the anti-rotation groove 41. Therefore, in some embodiments of the present invention, such as... Figure 5 As shown, the anti-rotation rib 331 has a first inclined surface 3311 machined at one end facing the anti-rotation groove 41, and at the same time, as Figure 4As shown, the anti-rotation groove 41 has a second inclined surface 411 on the groove wall near the anti-rotation rib 331, which is adapted to the first inclined surface 3311. During the movement of the clutch block 4 in the coupled position, the first inclined surface 3311 and the second inclined surface 411 come into contact and slide together. With the guiding effect of the inclined surfaces, the anti-rotation rib 331 can be smoothly guided into the anti-rotation groove 41, completing the alignment and insertion of the two. The design of the first inclined surface 3311 and the second inclined surface 411 effectively reduces the difficulty of alignment when the clutch block 4 slides from the decoupled position to the coupled position, avoids jamming between the anti-rotation rib 331 and the groove wall of the anti-rotation groove 41, and ensures smooth position switching of the clutch block.

[0042] In some embodiments of the present invention, such as Figure 11 As shown, a sliding groove 121 extending along a first direction is provided inside the housing 1, such as... Figure 4 As shown, a sliding rib 42 is correspondingly provided on the outer wall of the clutch block 4, and the sliding rib 42 forms a sliding fit with the sliding groove 121. During the movement of the clutch block 4 between its coupling position and decoupling position, the sliding rib 42 always slides along the direction of the sliding groove 121, thereby restricting the movement trajectory of the clutch block 4 and ensuring that the clutch block 4 can only move in a straight line in the first direction, making its movement smooth, stable and controllable. At the same time, it further ensures the accurate alignment of the anti-rotation groove 41 and the anti-rotation rib 331, improving the reliability of the product.

[0043] In some embodiments of the present invention, such as Figure 3 As shown, an elastic element 5 is provided between the housing 1 and the clutch block 4, which can continuously provide an elastic force along the first direction to the clutch block 4. In the injection state, the drug storage device 2, through its assembly with the housing 1, limits the clutch block 4. At this time, the elastic element 5 is in an energy storage state, generating downward pressure on the clutch block 4 along the first direction. This keeps the clutch block 4 stably in the coupling position. When the drug storage device 2 switches from the injection state to the drug replacement state, the drug storage device 2 releases the limiting constraint on the clutch block 4. At this time, the elastic element 5 releases its stored energy, pushing the clutch block 4 to automatically move from the coupling position to the decoupling position. There is no need to manually adjust the position of the clutch block 4, or to place the injection pen vertically so that the clutch block 4 can be displaced by its own weight. This releases the anti-rotation of the clutch block 4 against the guide 33, thereby allowing the piston rod 31 to gain freedom in the second direction for reset. This effectively simplifies the operation steps of resetting the injection pen in this embodiment and improves its ease of use.

[0044] Specifically, in this embodiment, a spring is selected as the elastic element 5 to drive the clutch block 4. The spring has the advantages of simple structure, stable elastic force, and low cost. In order to avoid the spring from tilting during the extension and contraction process, which would cause uneven force on the clutch block 4 and lead to its movement jamming, a positioning ring 122 is fixedly installed inside the housing 1, and a positioning groove 43 is opened on the clutch block 4. The upper end of the spring is sleeved on the outside of the positioning ring 122 to achieve fixed positioning, and the lower end is accommodated in the positioning groove 43, so that the two ends of the spring are stably connected to the housing 1 and the clutch block 4. Since the clutch block 4 slides in the housing 1 along the first direction, the way the spring is set can ensure that its elastic force is always applied to the clutch block 4 along the first direction, so that the clutch block 4 can be continuously pressed in the coupling position, and can ensure that the elastic force on the clutch block 4 is very uniform, thereby ensuring that the position switching of the clutch block 4 is always stable and reliable.

[0045] Of course, in this embodiment, the elastic element 5 can also be selected in other ways, such as using an airbag, hydraulic pressure, elastic rubber ring or elastic rope, etc. However, compared with springs, these methods are difficult to adapt to the small size and high assembly precision requirements of injection pens, and cannot effectively control product costs.

[0046] Furthermore, such as Figure 4 As shown, the anti-rotation groove 41 on the clutch block 4 is arranged on the inner wall of the positioning groove 43, while the sliding rib 42 is arranged on the outer wall of the positioning groove 43, so that the positioning groove 43 forms an upward opening structure. The inner and outer sides of the positioning groove 4 are respectively provided with a structure in which the clutch block 4 slides with the housing 1 and a structure in which the clutch block 4 anti-rotation with the guide 33. This effectively integrates the relevant structures on the clutch block 4, controls the product volume, and ensures that each part is independent of each other and will not cause positional interference, thus ensuring the reliability of the clutch block 4's sliding, elastically driven, and anti-rotation functions.

[0047] In some embodiments of the present invention, such as Figure 6 , Figure 7 As shown, the interior of the housing 1 is also provided with a recessed groove 123 extending along the first direction, correspondingly, as... Figure 3 , Figure 4 As shown, a slider 44 is fixed on the outer wall of the clutch block 4. The slider 44 is slidably assembled inside the recess 123. On the one hand, it forms a double guiding structure with the aforementioned sliding groove 121 and sliding rib 42, further guiding the sliding of the clutch block 4 and avoiding problems such as deflection and tilting of the clutch block 4, thus ensuring the smooth movement of the clutch block 4. On the other hand, the lower end wall of the recess 123 can form a limiting block on the slider 44, thereby preventing the clutch block 4 from detaching from the housing 1 when moving from the coupling position to the decoupling position by limiting the stroke of the slider 44, avoiding problems such as loss of parts, and improving the safety and durability of the product.

[0048] Furthermore, such as Figure 6 , Figure 7 As shown, the upper surface of slider 44 is a third inclined surface 441 extending obliquely along the first direction. That is, viewed from the side, slider 44 is a triangle or trapezoid with a smaller top and a larger bottom. Figure 6 , Figure 7 , Figure 11 As shown, the recess 123 for accommodating the slider 44 is formed on the protrusion 124 inside the housing 1. At the position of the lower end of the recess 123 on the protrusion 124, a fourth inclined surface 1241 is provided that can slide and cooperate with the third inclined surface 441. When the clutch block 4 is assembled onto the housing 1, it is only necessary to align the third inclined surface 441 with the recess 123 and then push the clutch block 4 upward on the lower inner side of the housing 1. The third inclined surface 441 can then guide the slider 44 into the recess 123, thereby reducing the assembly difficulty of the clutch block 4.

[0049] Furthermore, such as Figure 6 As shown, a protrusion 1242 is provided at the lower end of the protrusion 124, and a fourth inclined surface 1241 is correspondingly provided on the protrusion 1242, as shown. Figure 6 , Figure 7 As shown, an annular rib 45 is provided on the outer side of the clutch block 4. The annular rib 45 has a cut 451 that matches the shape of the protrusion 1242. When the clutch block 4 slides upward to the coupling position, the protrusion 1242 is just accommodated inside the cut 451, forming a locking fit in the second direction. This fits with the sliding rib 42 and the sliding groove 121 in the coupling position, where the housing 1 engages with the anti-rotation action of the clutch block 4. This further anti-rotation positioning of the clutch block 4 improves the overall stability of the anti-rotation fit, effectively ensuring that the clutch block 4 will not shake or shift in the coupling position, thus ensuring a smooth and reliable injection process.

[0050] In some embodiments of the present invention, such as Figure 3 , Figure 6 , Figure 8 As shown, the drug storage device 2 is engaged with the locking block 211 on its upper part and the corresponding locking groove 125 on the lower part of the housing 1 to achieve the detachable and fixed assembly of the drug storage device 2 and the housing 1, thereby forming the injection state of the injection pen.

[0051] During the assembly and use of the injection pen, after resetting the piston rod 31, the drug storage device 2 is aligned with the lower part of the housing 1 for installation, so that the locking block 211 engages with the locking groove 125, thus forming the injection state. This, in conjunction with the internal clutch block 4, guide 33, piston rod 31, and other structures, allows for drug injection. When medication needs to be changed, by releasing the locking block 211 from the locking groove 125, the drug storage device 2 can be separated from the housing 1, switching it to the medication change state. This provides operational space for resetting the piston rod 31, changing medication, or replenishing medication, achieving flexible switching between injection and medication change states while maintaining a simple structure and reliable assembly.

[0052] In this embodiment, the drug storage device 2 and the housing 1 can also be fixedly assembled by other detachable connection methods such as threaded connection and interference fit. The structural forms are flexible and diverse, and all of them can realize the switching between the injection state and the drug changing state of the drug storage device 2, and can effectively ensure the connection stability.

[0053] Specifically, such as Figure 6 , Figure 7 As shown, the locking groove 125 at the lower part of the housing 1 includes an inlet section 1251 and a locking section 1252 that are interconnected. The inlet section 1251 extends along a first direction, and the locking section 1252 extends along a second direction, forming a groove structure that is introduced in the first direction and moves to the locking position in the second direction. When the drug storage device 2 switches from the drug changing state to the injection state, the locking block 211 on the upper part of the drug storage device 2 is aligned with the inlet section 1251, and the drug storage device 2 is pushed along the first direction, so that the locking block slides into the groove along the inlet section 1251. After the locking block 211 slides to the upper end of the inlet section 1251, the drug storage device 2 is rotated, so that the locking block 211 slides into the groove of the locking section 1252 along the second direction. The locking block 211 is then limited in the first direction by the side wall of the groove of the locking section 1252, so that the drug storage device 2 and the housing 1 are stably assembled and the two will not separate in the first direction.

[0054] Furthermore, such as Figure 6 , Figure 7As shown, the inlet section 1251 is formed on the inner sidewall of the housing 1, while the locking section 1252 penetrates the sidewall of the housing 1. At the location where the locking block 211 is installed on the drug storage device 2, its overall radial dimension, i.e., its diameter perpendicular to the first direction, is greater than the inner diameter of the inlet section 1251 on the housing 1. In this configuration, when the locking block 211 slides along the inlet section 1251, the two form an interference fit. When the locking block 211 enters the locking section 1252, since the locking section 1252 penetrates the sidewall of the housing 1, the locking block 211 is confined within the locking section 1252, forming a double limit in both the first and second directions. This prevents the drug storage device 2 from rotating and slipping off the housing 1 at will, ensuring the connection stability of the two during injection.

[0055] Furthermore, since the radial dimension of the locking block 211 is larger than the inner diameter of the inlet section 1251, in order for the locking block 211 to smoothly enter the inlet section 1251 during the upward assembly of the drug storage device 2 to the lower part of the housing 1, as follows: Figure 3 , Figure 8 As shown, the upper end of the locking block 211 is machined into a conical surface structure, which reduces the assembly difficulty by using its inclined transition.

[0056] In some embodiments of the present invention, a circumferential locking structure is provided between the drug storage device 2 and the clutch block 4. When the drug storage device 2 is assembled and in the injection state, the clutch block 4 is mutually locked with the clutch block 4 by means of the circumferential locking structure. Since the clutch block 4 and the housing 1 are anti-rotation in the second direction, the drug storage device 2 can also be anti-rotation limited in the second direction, so that the drug storage device 2 remains fixed in the injection state, further improving the overall assembly stability of the injection pen, so as to ensure that the injection operation can be carried out stably.

[0057] Specifically, such as Figure 3 , Figure 4 , Figure 8 As shown, the aforementioned circumferential locking structure consists of a locking groove 212 and a locking protrusion 46, both of which extend along the first direction and are respectively located on the upper part of the drug storage device 2 and the lower part of the clutch block 4. When the drug storage device 2 is in the injection state, the locking protrusion 46 on the clutch block 4 is embedded in the locking groove 212 of the drug storage device 2, thereby locking the drug storage device 2 in the second direction by means of the locking cooperation between the two, so that it remains fixed in the injection state. Obviously, the positions of the locking groove 212 and the locking protrusion 46 can be interchanged, that is, the locking groove 212 is located on the lower part of the clutch block 4, while the locking protrusion 46 is located on the upper part of the drug storage device 2, which can achieve the aforementioned effect.

[0058] Furthermore, since the clutch block 4 can slide inside the housing 1 along the first direction, therefore... Figure 3 , Figure 4 , Figure 8 As shown, the two side walls 2121 of the locking groove 212 and the two side surfaces 461 of the locking protrusion 46 are all inclined. When the medicine storage device 2 is rotated, causing the locking block 211 to disengage from the locking section 1252, the side walls 2121 of the locking groove 212 will abut against the side surfaces 461 of the locking protrusion 46. Thus, with the help of the force transmission of the inclined surface, the clutch block 4 will slide towards the upper part of the housing 1, and finally the locking protrusion 46 will disengage from the locking groove 212, thereby releasing the restriction between the two in the second direction, so as to separate the medicine storage device 2 from the housing 1.

[0059] In some embodiments of the present invention, since the elastic element 5 always presses the clutch block 4 downward, the locking protrusion 46 can always be stably locked in the locking groove 212 during the injection state. This ensures that the limiting fit between the locking protrusion 46 and the locking groove 212 will not be arbitrarily released due to improper use of the injection pen or other operational problems, thus keeping the drug storage device 2 locked to the clutch block 4 and ensuring stability during the injection operation.

[0060] Furthermore, such as Figure 3 , Figure 4 As shown, the outer side of the clutch block 4 is provided with an annular rib 45. When the drug storage device 2 is assembled onto the housing 1 and is in the injection state, the lower end face of the annular rib 45 presses against the upper end face of the drug storage device 2. This, combined with the downward pressure of the elastic element 5 on the clutch block 4, further tightens the assembly of the drug storage device 2, eliminates the assembly gap between the drug storage device 2 and the housing 1 in the first direction when in the injection state, prevents the drug storage device 2 from moving, and ensures the assembly stability in the first direction.

[0061] In some embodiments of the present invention, since general liquid injectable drugs are stored in sealed glass containers, in order to ensure that the glass containers are not broken during injection and thus do not cause safety issues, such as... Figure 2 , Figure 8As shown, the drug storage device 2 mainly consists of a drug compartment 21 and a drug bottle 22, with the drug bottle 22 installed inside the drug compartment 21. On the one hand, the drug compartment 21 provides a safe and stable space for the drug bottle 22 and plays a positioning role, thereby preventing the drug bottle 22 from shifting or being damaged by bumps during use. On the other hand, since the upper part of the drug storage device 2 needs to be detachably connected to the housing 1, it is necessary to process more structures, such as the aforementioned locking block 211 and snap-fit ​​groove 212, to adapt to the housing 1. Therefore, the separate design of the drug compartment 21 and the drug bottle 22 in the drug storage device 2 can also avoid the need for adaptation processing of the drug bottle 22, thereby facilitating the disassembly and replacement of the drug bottle 22. Even a drug bottle 22 that can be assembled into the drug compartment 21 can be used for drug injection by the injection pen in this embodiment. In addition, the structure of the medicine chamber 21 can be used to achieve accurate alignment with the shell 1 and the clutch block 4, so that the piston rod 31 can accurately enter the medicine bottle 22, thereby injecting the medicine in the medicine bottle 22.

[0062] Furthermore, such as Figure 8 As shown, the medication chamber 21 is designed as a cylindrical structure with an open top. This allows the medication bottle 22 to be inserted through the opening, and the piston rod 31 can enter the chamber and eventually reach the rear end of the bottle 22 to inject the medication. In this embodiment, to ensure stable connection of the bottle 22 within the chamber along the first direction, the elastic element 5 presses downwards against the clutch block 4. Therefore, the clutch block 4 can also partially enter the chamber and press against the upper surface of the bottle 22, effectively sealing the bottle 22 within the chamber. This restricts movement of the bottle 22 along the first direction, ensuring its stability during injection and preventing it from affecting injection accuracy. Furthermore, movement of the bottle 22 could cause the connected needle 23 to shake, potentially causing discomfort or injury to the patient. This ensures both safety and stability during use.

[0063] In some embodiments of the present invention, such as Figure 2 , Figure 7 As shown, the housing 1 is composed of an outer shell 11 and a mounting base 12 assembled inside the outer shell 11. The clutch block 4 is movably connected to the mounting base 12, as shown. Figure 9 , Figure 10As shown, the housing 11 has a mounting surface 111 perpendicular to the first direction inside. The mounting surface 111 has mounting holes 1111. The mounting base 12 and the driving component 32 are respectively located on both sides of the mounting surface 111 and are connected and fixed to each other by a snap-fit ​​structure passing through the mounting holes 1111, thereby connecting the driving component 32 to the housing 1. Since the housing 11 only has the mounting surface 111 inside, and there are no other overlapping parts along the first direction inside the housing 11, the existing design avoids the need for perforation and other processing in the horizontal and vertical directions of the housing 11 when attaching other components. This allows for the integration of multiple structures onto a single housing 11. Only injection molding is required, and demolding can be performed on the upper and lower sides of the housing 11 along the first direction. This transforms the complex injection molding and other processing of the housing 1 into a stable injection molding process for the housing 11 and the mounting base 12, effectively improving production efficiency and product yield. Furthermore, it avoids replacing the entire housing 1 when a single component is damaged, saving costs.

[0064] Specifically, such as Figure 6 , Figure 7 , Figure 12 As shown, the snap-fit ​​structure between the mounting base 12 and the drive component 32 consists of a snap-fit ​​hole 127 on the extension arm 126 of the mounting base 12 and a snap-fit ​​hook 321 on the drive component 32. The number and position of the two are matched. During assembly, the extension arm 126 passes through the mounting hole 1111 on the housing 11 and achieves a snap-fit ​​locking engagement with the snap-fit ​​hook 321 through the snap-fit ​​hole 127. This allows the mounting base 12 and the drive component 32 to fit against the two sides of the mounting surface 111 respectively. No screws or other fasteners are needed. The assembly of the drive component 32 and the housing 11 can be completed in one step. At the same time, the assembly position of the mounting base 12 and the drive component 32 is effectively guaranteed, ensuring the assembly accuracy of the internal structure of the injection pen. In addition, the housing 11 can be used for different types of injection pens. Only the structure of the mounting base 12 or the drive component 32 needs to be replaced, ensuring the universality of the parts and adapting to large-scale modular production.

[0065] In some embodiments of the present invention, such as Figure 6 , Figure 7 , Figure 11As shown, an annular positioning rib 128 is also provided on the outer side of the mounting base 12. After the mounting base 12 and the driving component 32 are connected and assembled through the snap-fit ​​structure, the lower end face of the outer shell 11 abuts against the upper end face of the annular positioning rib 128, and the lower end face of the driving component 32 abuts against the mounting surface 111 inside the outer shell 11. For the mounting base 12, the driving component 32 is pulled upward by the snap-fit ​​structure, while the annular positioning rib 128 is tightly attached to the lower end face of the outer shell 11, so that the mounting base 12 remains stable in the first direction and does not move up and down, avoiding problems with usage stability and injection accuracy; for the driving component 32, the mounting base 12 is pulled downward by the snap-fit ​​structure, and its lower end face abuts against the mounting surface 111 to prevent it from moving downward, so that the driving component 32 also remains stable in the first direction and does not move up and down, avoiding problems with usage stability and injection accuracy.

[0066] Furthermore, in order to ensure the stable and reliable installation of the mounting base 12 and the drive component 32, the projections of the extension arm 126 and the hook 321 along the first direction need to partially overlap. Therefore, the end faces of the extension arm 126 and the hook 321 are both designed with an inclined structure to form an inclined guide fit structure. Thus, during assembly, the inclined end faces can play a guiding role, allowing the hook 321 to smoothly snap into the hook hole 127, avoiding the problem of the end faces of the extension arm 126 and the hook 321 being stuck together when the plane is set, which would prevent assembly.

[0067] Furthermore, such as Figure 10 As shown, the inner wall of the outer casing 11 is also provided with a receiving groove 112 communicating with the mounting hole 1111. On a plane perpendicular to the first direction, the size of the receiving groove 112 is not larger than the size of the mounting hole 1111, thereby ensuring that during the processing, the injection molding of the outer casing 11 can be completed simply by demolding along the first direction, ensuring the simplicity of processing and manufacturing. In addition, since the extension arm 126 is squeezed by the drive component 32 or its hook 321 during and after assembly, causing it to have a certain degree of deflection, the receiving groove 112 can provide a certain receiving space for the extension arm 126, effectively utilizing the internal space of the outer casing 11, which is conducive to the compact assembly of the product, effectively making the product more miniaturized and convenient for users.

[0068] Furthermore, such as Figure 10 , Figure 11 , Figure 12As shown, both the mounting base 12 and the driving component 32 are slidably engaged with the outer casing 11 via guide grooves 322 and guide ribs 113. That is, both the mounting base 12 and the driving component 32 are provided with guide grooves 322 extending along the first direction, while the inner wall of the outer casing 11 is provided with guide ribs 113 that match the guide grooves 322. Through the guiding engagement of the guide ribs 113 and the guide grooves 322, the rotation of the mounting base 12 or the driving component 32 relative to the outer casing 11 is restricted, ensuring that both can only enter the interior of the outer casing 11 along the first direction and complete the snap-fit ​​connection. This ensures the accurate alignment of the aforementioned hooks 321 and hook holes 127, guarantees assembly accuracy, and avoids problems such as component misalignment and jamming.

[0069] In some embodiments of the present invention, such as Figure 11 As shown, the mounting base 12 has a through hole 129 through which the guide member 33 can be installed. The upper end of the guide member 33 is a positioning end 332, which passes through the through hole 129 and forms a rotatable connection with the mounting base 12 at the through hole 129. This allows the guide member 33 to be fixed in the first direction and rotated in the second direction relative to the mounting base 12, thus ensuring the functional realization of the guide member 33.

[0070] Specifically, such as Figure 5 As shown, the positioning end 332 includes multiple elastic arms arranged along a second direction. Each elastic arm extends along a first direction and has a lower rotating section 3321 and an upper positioning section 3322. The multiple elastic arms together form a mushroom-shaped positioning end 332. When it is rotatably connected to the through hole 129, the rotating section 3321 is located inside the through hole 129, and the positioning section 3322 abuts against the upper end face of the through hole 129. The multiple elastic arms are spaced apart, giving it a certain deformation capability. When the positioning end 332 is inserted into the through hole 129, the elastic arms can deform to a certain extent, allowing the positioning section 3322 to pass through the through hole 129, reducing resistance during assembly. After passing through, the positioning section 3322 axially positions the entire guide 33 on the mounting base 12, thus ensuring the rotation of the guide 33 relative to the mounting base 12 while preventing movement between the two in the first direction, effectively ensuring the stability of the guide 33's installation structure and the ease of assembly.

[0071] In some embodiments of the present invention, such as Figure 2As shown, the delivery system 3 is used to inject the medicine in the vial 22. The driving component 32 consists of a fixing screw 323 fixed to the outer shell 11 and a driving rod 324 that can rotate relative to the outer shell 11. The hook 321 and the guide groove 322 are fixedly set on the fixing screw 323, while the driving rod 324 can be threadedly connected to the piston rod 31. Thus, the driving component 32 drives the piston rod 31 to feed during the unidirectional rotation of the driving rod 324 relative to the fixing screw 323. The driving component 32 can also be fixedly connected to the shell 1 through the hook 321 and the guide groove 322. In addition to the piston rod 31, drive member 32, and guide member 33 mentioned above, the injection pen delivery system 3 in this embodiment also includes a button 34 disposed on the upper end of the housing 1, a scale rod 35 connected to the button 34, and a transmission rod 36 connected to the scale rod 35. The scale rod 35 is threadedly connected to the fixing screw 323. In addition, a display window 114 is provided on the housing 11 to display the scale on the outer wall of the scale rod 35.

[0072] In some embodiments of this invention, the assembly process of the injection pen is as follows: Step S1: Insert the scale rod 35, transmission rod 36, and button 34 into the upper end of the fixing screw 323 respectively, and then insert the drive rod 324 and piston rod 31 into the lower end of the fixing screw 323 to form the first part of the assembly. Step S2: The assembled first part of the assembly is inserted into the interior of the outer shell 11 from the top along the first direction. The guide groove 323 on the fixing screw 323 cooperates with the guide rib 113 inside the outer shell 11, so that the guide rib 113 forms a guiding effect in the first direction and a limiting effect in the second direction on the first part of the assembly. Step S3: Insert the guide 33 from the lower part of the mounting base 12 upward into the through hole 129 in the mounting base 12. The positioning end 332 and the through hole 129 form a rotational fit in the second direction and a limiting fit in the first direction, so as to form the second part of the assembly. Step S4: Insert the second part assembly into the housing 11 from the lower part along the first direction, so that the piston rod 31 passes through the guide 33 and the extension arm 126 passes through the mounting hole 1111. Then the hook hole 127 will lock with the hook 321, thereby locking the mounting base 12 and the drive member 32. Step S5: Insert the elastic element 5 and the clutch block 4 sequentially from the bottom of the mounting base 12. During this process, the elastic element 5 is fitted into 122 and the positioning groove 43, while the slider 44 can slide into the recess 123, so that the elastic element 5 and the clutch block 4 are both attached to the lower part of the mounting base 12.

[0073] Step S6: Align the drug storage device 2 with the lower part of the mounting base 12 and push it upward in the first direction until the locking block 211 enters the locking section 1252 along the inlet section 1251. Then rotate the drug storage device 2. Due to size limitations, the locking block 211 will be locked in the locking section 1252. At the same time, the protrusion 1242 enters the break 451, the snap protrusion 46 enters the snap groove 212, and the lower end face of the annular rib 45 presses on the upper end face of the drug storage device (2). The clutch block 4 will also press the medicine chamber 21 and the medicine bottle 22, thus forming a stable assembly. At this time, the clutch block is in the coupling position, and the injection pen is in the injection state.

[0074] In some embodiments of the present invention, step S6 is also the process by which the drug storage device switches from the drug changing state to the injection state in some embodiments of the present invention.

[0075] In some embodiments of the present invention, step S6 is reversed. That is, the drug storage device 2 is first rotated to disengage the locking block 211 from the locking section 1252, and then the drug storage device 2 is disengaged from the lower part of the mounting base 12 in the first direction downwards, so that it is in the drug replacement state, thereby refilling the drug in the drug storage device 2 or replacing the medicine bottle 22. At the same time, the clutch block 4 is in the decoupled position, thereby releasing the anti-rotation limit on the guide 33, and the piston rod 31 can be manually rotated to reset it to the initial state, thereby preparing for the next injection.

[0076] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0077] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. An injection pen, characterized in that, include: Shell (1); The drug storage device (2) is detachably connected to the housing (1) and has an injection state fixed to the housing (1) and a drug replacement state unfixed to the housing (1); The delivery system (3) includes a piston rod (31) for delivering the drug in the drug storage device (2) and a drive assembly for driving the piston rod (31). The drive assembly includes a drive member (32) and a guide member (33). The guide member (33) is rotatably disposed on the housing (1). One of the drive member (32) and the guide member (33) is slidably connected to the piston rod (31) and can slide relative to the piston rod (31) in a first direction. The other is threadedly connected to the piston rod (31) and can rotate relative to the piston rod (31) in a second direction. The clutch block (4) is movably disposed in the housing (1) and has a coupling position that restricts the rotation of the guide member (33) and a decoupling position that releases the restriction on the rotation of the guide member (33). When the drug storage device (2) is switched to the injection state, the clutch block (4) moves to the coupling position to stop the rotation of the guide member (33), so that the drive member (32) can drive the piston rod (31) to move downward by rotation to inject the drug in the drug storage device (2); when the drug storage device (2) is switched to the drug changing state, the clutch block (4) can move to the decoupling position to disengage from the guide member (33), so that the piston rod (31) can be driven upward by external force to reset. The shell (1) is formed into a cylindrical shape, the first direction is along the length of the shell (1), and the second direction is the circumferential direction in a plane perpendicular to the first direction.

2. The injection pen according to claim 1, characterized in that, When the clutch block (4) moves to the coupling position, the clutch block (4) and the guide member (33) engage with each other through the anti-rotation groove (41) and anti-rotation rib (331) extending along the first direction to prevent the guide member (33) from rotating.

3. The injection pen according to claim 2, characterized in that, Both the anti-rotation groove (41) and the anti-rotation rib (331) include a plurality of corresponding ones, one of which is distributed on the outside of the guide (33), and the other is distributed on the inside of the clutch block (4).

4. An injection pen according to claim 3, characterized in that, The anti-rotation rib (331) has a first inclined surface (3311) near one end of the anti-rotation groove (41), and the groove wall of the anti-rotation groove (41) has a second inclined surface (411) corresponding to the first inclined surface (3311) near one end of the anti-rotation rib (331). When the clutch block (4) moves to the coupling position, the first inclined surface (3311) and the second inclined surface (411) slide to engage, and the anti-rotation rib (331) is guided into the anti-rotation groove (41).

5. An injection pen according to any one of claims 1-4, characterized in that, The housing (1) has a sliding groove (121) extending along the first direction inside, and the clutch block (4) has a sliding rib (42) corresponding to the sliding groove (121) on the outside. The sliding groove (121) and the sliding rib (42) slide together.

6. An injection pen according to claim 5, characterized in that, It also includes an elastic element (5) disposed between the housing (1) and the clutch block (4). When the drug storage device (2) switches from the injection state to the drug change state, the elastic element (5) pushes the clutch block (4) to slide from the coupling position to the decoupling position.

7. An injection pen according to claim 6, characterized in that, The elastic element (5) is a spring, the housing (1) is provided with a positioning ring (122), the clutch block (4) is provided with a positioning groove (43), and the two ends of the spring are respectively sleeved on the positioning ring (122) and in the positioning groove (43).

8. An injection pen according to claim 7, characterized in that, The sliding rib (42) is provided on the outer wall of the positioning groove (43). When the clutch block (4) is provided with an anti-rotation groove (41) or an anti-rotation rib (331), the anti-rotation groove (41) or the anti-rotation rib (331) is provided on the inner wall of the positioning groove (43).

9. An injection pen according to any one of claims 6-8, characterized in that, The housing (1) has a recess (123) extending along the first direction inside, and a slider (44) is provided on the outside of the clutch block (4) and is slidably disposed in the recess (123).

10. An injection pen according to claim 9, characterized in that, The slider (44) is provided with a third inclined surface (441) extending along the first direction, and the groove (123) is formed on the protrusion (124) on the inner side of the housing (1). The protrusion (124) is provided with a fourth inclined surface (1241) at the lower end of the groove (123) that slides in cooperation with the third inclined surface (441).

11. An injection pen according to claim 10, characterized in that, The fourth inclined surface (1241) is provided on the protrusion (1242) at the lower end of the protrusion (124). The clutch block (4) is provided with an annular rib (45) on the outside. The annular rib (45) is provided with a break (451) that is adapted to the protrusion (1242). When the clutch block (4) is located in the coupling position, the protrusion (1242) is located in the break (451).

12. An injection pen according to any one of claims 1-4, 6-8, 10, and 11, characterized in that, The upper part of the drug storage device (2) is provided with a locking block (211), and the lower part of the housing (1) is provided with a locking groove (125). The locking block (211) cooperates with the locking groove (125). The locking groove (125) includes an inlet section (1251) extending along the first direction and a locking section (1252) extending along the second direction. When the drug storage device (2) switches from the drug changing state to the injection state, the locking block (211) enters the locking section (1252) from the inlet section (1251) to fix the drug storage device (2) to the housing (1) to form the injection state.

13. An injection pen according to claim 12, characterized in that, A locking groove (212) and a locking protrusion (46) extending along the first direction are provided between the drug storage device (2) and the clutch block (4). One of the locking groove (212) and the locking protrusion (46) is located on the upper part of the drug storage device (2), and the other is located on the lower part of the clutch block (4). When the drug storage device (2) is in the injection state, the locking protrusion (46) enters the locking groove (212), thereby restricting the rotation of the drug storage device (2) relative to the housing (1) when the drug storage device (2) is in the injection state.

14. An injection pen according to any one of claims 1-4, 6-8, 10, 11, and 13, characterized in that, The medicine storage device (2) includes an elastic element (5) and includes a medicine container (21) and a medicine bottle (22) installed in the medicine container (21). The medicine container (21) is formed into a cylindrical shape with an open top. When the medicine storage device (2) is in the injection state, the elastic element (5) presses the clutch block (4) downward, so that the clutch block (4) abuts against the upper end of the medicine bottle (22) to lock the medicine bottle (22) in the medicine container (21) along the first direction.

15. An injection pen according to claim 114, characterized in that, The housing (1) includes an outer shell (11) and a mounting base (12). The clutch block (4) is movably connected to the mounting base (12). The outer shell (11) has a mounting surface (111) extending perpendicular to the first direction. The mounting surface (111) has a mounting hole (1111). The mounting base (12) and the drive member (32) are respectively located on both sides of the mounting surface (111) and connected by a snap-fit ​​structure passing through the mounting hole (1111).

Images