Insulin injection pen and method of using the same

Abstract

The application discloses an insulin injection pen, comprising: a pen body, one end of the pen body being provided with a mounting portion; a needle seat, one end of the needle seat, which is away from the pen body, being provided with a needle, the other end of the needle seat being provided with a mounting cavity which is suitable for detachable cooperation with the mounting portion; and a protective cap, the protective cap being provided with a avoiding opening which is suitable for the needle to pass through, the protective cap being sleeved on the needle seat, the protective cap being in sliding cooperation with the needle seat, the protective cap being movable along the axial direction of the needle seat between a needle exposing position and a protective position, in the needle exposing position, the needle passes through the avoiding opening and extends out of the protective cap, in the protective position, the needle is located in the protective cap. The application also relates to a method for using the insulin injection pen. According to the insulin injection pen, after the insulin injection pen completes injection, the needle can be prevented from pricking, the pen cap does not need to be sleeved, the clinical nursing requirement and nursing regulation can be met, and the use safety of the insulin injection pen can be ensured.

Description

Technical Field

[0001] This invention relates to the field of medical devices, and in particular to an insulin pen and its method of use. Background Technology

[0002] Diabetes is a prevalent disease that can occur in all age groups. Persistent hyperglycemia and long-term metabolic disorders can affect the whole body’s tissues and organs. In the treatment of diabetes, insulin injection is a common medical procedure, usually administered using an insulin pen.

[0003] However, according to clinical nursing needs, insulin pens in related technologies require the pen cap to be put back on before rotating the discarded needle to avoid needlestick injuries. But according to nursing regulations, the pen cap cannot be put back on after the insulin injection is completed. Obviously, insulin pens in related technologies cannot simultaneously meet both clinical nursing needs and nursing regulations, and it is necessary to improve them. Summary of the Invention

[0004] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes an insulin pen that avoids needle pricks after injection and eliminates the need to recap the pen, while simultaneously meeting clinical nursing needs and regulations, thus contributing to the safe use of the insulin pen.

[0005] An insulin injection pen according to an embodiment of the present invention includes: a pen body, one end of which is provided with a mounting portion; a needle holder, one end of which is provided with a needle away from the pen body, and the other end of which is provided with a mounting cavity adapted to detachably engage with the mounting portion; and a protective cap, which has a clearance opening adapted for the needle to pass through, the protective cap being fitted over the needle holder, the protective cap being slidably engaged with the needle holder, and the protective cap being movable between a needle-exposed position and a protected position along the axial direction of the needle holder. In the needle-exposed position, the needle passes through the clearance opening and extends out of the protective cap; in the protected position, the needle is located inside the protective cap.

[0006] According to an embodiment of the present invention, the insulin pen has a movable protective cap. During insulin injection, the protective cap can be adjusted to the needle-exposed position so that the needle protrudes. After the insulin injection is completed, the protective cap can be moved to the protective position to retract the needle into the protective cap. Then, the needle holder and the protective cap can be detached from the pen body as a whole. Thus, after the insulin pen is used for injection, needle puncture can be avoided, and there is no need to put the pen cap back on. At the same time, it can meet the clinical nursing needs and nursing regulations, which helps to ensure the safe use of the insulin pen.

[0007] In some embodiments of the present invention, the needle holder is provided with a sliding groove, the sliding groove including a first groove segment and a second groove segment, the first groove segment extending in the length direction of the mounting portion, one end of the second groove segment being connected to the end of the first groove segment opposite to the needle, and the other end of the second groove segment extending along the circumferential direction of the insulin pen, the protective cap being provided with a sliding block, the sliding block being adapted to slide and engage with the first groove segment and the second groove segment.

[0008] In some embodiments of the present invention, the insulin pen further includes a needle ejection mechanism, the needle ejection mechanism including a locking assembly and an elastic member, the locking assembly being disposed between the needle holder and the mounting portion to lock or unlock the needle holder, the elastic member being disposed between the needle holder and the mounting portion, the elastic member extending in the axial direction of the mounting portion and being normally in a compressed state, the locking assembly being adapted to unlock the needle holder when the protective cap is in the protective position so that the protective cap and the needle holder are ejected under the action of the elastic member.

[0009] In some embodiments of the present invention, the free end of the mounting portion is provided with an annular protrusion, the annular protrusion defining the liquid outlet of the pen body, the liquid outlet communicating with the needle, the elastic member being located between the annular protrusion and the inner wall of the mounting cavity and extending along the axial direction of the mounting portion, one end of the elastic member being connected to the inner wall of the mounting cavity, and the other end of the elastic member being connected to the mounting portion.

[0010] In some embodiments of the present invention, one end of the elastic member is bonded to the inner wall of the mounting cavity, and the other end of the elastic member abuts against the mounting portion; or, one end of the elastic member abuts against the inner wall of the mounting cavity, and the other end of the elastic member is bonded to the mounting portion.

[0011] In some embodiments of the present invention, the lock assembly includes a spring and a latch, and the outer peripheral wall of the mounting portion is provided with a mounting groove suitable for mounting the spring and the latch, wherein the spring is connected between the bottom wall of the mounting groove and the latch.

[0012] In some embodiments of the present invention, the needle ejection mechanism further includes a sliding post and a sliding button. The needle seat is provided with a mating hole in the radial direction of the needle seat. The sliding post is slidably engaged with the mating hole. The protective cap is also provided with a sliding button adapted to move along the radial direction of the protective cap. When the protective cap is in the protective position, the sliding button, the sliding post and the latch are opposite each other in the radial direction of the mounting part.

[0013] In some embodiments of the present invention, the side of the latch facing away from the spring is provided with a hemispherical portion, and the end of the needle holder facing the pen body is provided with a guide surface. In the direction from the pen body to the needle, the guide surface extends obliquely toward the axis of the needle holder.

[0014] In some embodiments of the present invention, there are two mounting slots, which are arranged opposite to each other in the radial direction of the mounting portion.

[0015] In some embodiments of the present invention, the insulin pen further includes a pen cap adapted to engage with the protective cap to define a receiving space, wherein the needle is located within the receiving space.

[0016] In some embodiments of the present invention, the present invention also provides a method of using the insulin injection pen as described above, characterized in that the method includes the following steps:

[0017] S1: When the protective cap is in the exposed needle position, complete the injection, and then switch the protective cap to the protective position;

[0018] S2: Separate the protective cap and the needle holder as a whole from the pen body.

[0019] In some embodiments of the present invention, in step S2 above, separating the protective cap and the needle holder as a whole from the pen body includes ejecting the protective cap and the needle holder as a whole from the pen body via a needle ejection mechanism. The needle ejection mechanism includes a locking component and an elastic element. The locking component is disposed between the needle holder and the mounting portion to lock or unlock the needle holder. The elastic element is disposed between the needle holder and the mounting portion. The elastic element extends in the axial direction of the mounting portion and is normally in a compressed state. When the protective cap is in the protective position, the locking component is adapted to unlock the needle holder so that the protective cap and the needle holder are ejected under the action of the elastic element.

[0020] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0021] Figure 1 This is a three-dimensional schematic diagram of an insulin injection pen according to an embodiment of the present invention;

[0022] Figure 2 yes Figure 1 The diagram shows an explosion of an insulin pen.

[0023] Figure 3 yes Figure 1A cross-sectional view of the insulin pen shown;

[0024] Figure 4 This is an exploded view of a needle holder, protective cap, needle ejection mechanism, and pen cap according to an embodiment of the present invention;

[0025] Figure 5 This is an assembly diagram of a needle holder, protective cap, needle ejection mechanism, and pen cap according to an embodiment of the present invention;

[0026] Figure 6 yes Figure 5 Enlarged view of point A in the middle;

[0027] Figure 7 yes Figure 5 An explosion diagram;

[0028] Figure 8 This is a schematic diagram of the needle holder according to an embodiment of the present invention;

[0029] Figure 9 This is a schematic diagram of an insulin injection pen according to an embodiment of the present invention, wherein the pen cap is fitted onto a protective cap;

[0030] Figure 10 This is a schematic diagram of an insulin injection pen according to an embodiment of the present invention, wherein the pen cap is removed from the protective cap, and the protective cap is in the needle-exposed position;

[0031] Figure 11 This is a schematic diagram of an insulin injection pen according to an embodiment of the present invention, wherein the protective cap is in the protective position and the locking assembly locks the needle holder;

[0032] Figure 12 This is a schematic diagram of an insulin injection pen according to an embodiment of the present invention, wherein the protective cap is in the protective position and the locking assembly unlocks the needle holder;

[0033] Figure 13 This is a schematic diagram of an insulin injection pen according to an embodiment of the present invention, wherein the protective cap and the needle hub pop out together;

[0034] Figure 14 This is a schematic diagram of an insulin injection pen according to another embodiment of the present invention.

[0035] Figure label:

[0036] Insulin pen 100;

[0037] 10. Pen body; 11. Mounting part; 12. Annular protrusion; 13. Mounting groove;

[0038] Needle holder 20; needle 21; mounting body 211; mounting cavity 22; sliding groove 23; first groove section 231; second groove section 232; mating hole 24;

[0039] 30; protective cap; 31; sliding block; 32; sliding hole; 33; guide surface;

[0040] Needle ejection mechanism 40; locking assembly 41; spring 411; latch 412; hemispherical part 413; elastic element 42; sliding post 43; sliding button 44;

[0041] Pen cap 50. Detailed Implementation

[0042] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0043] The following disclosure provides numerous different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. Additionally, examples of various specific processes and materials are provided in this invention; however, those skilled in the art will recognize the applicability of other processes and / or the use of other materials.

[0044] The following is a reference appendix. Figure 1-14 An insulin pen 100 according to an embodiment of the present invention is described.

[0045] Reference Figure 1-4 As shown, the insulin pen 100 according to an embodiment of the present invention may include: a pen body 10, a needle holder 20, and a protective cap 30.

[0046] Reference Figure 1 and Figure 2 As shown, one end of the pen body 10 (refer to) Figure 2 The pen body 10 has a mounting part 11 at the left end, and the injection mechanism (not shown) is located inside the pen body 10. The injection mechanism is connected to the needle holder 20 through the mounting part 11.

[0047] Reference Figures 2-4 As shown, the end of the needle holder 20 that is away from the pen body 10 (refer to...) Figure 2The needle head 21 is provided at the right end of the needle head 20, and the other end of the needle head 20 is provided with a mounting cavity 22 suitable for detachable engagement with the mounting part 11. For example, the needle head 20 can be connected to the mounting part 11 by a snap or threaded connection.

[0048] Reference Figure 5 and Figure 6 As shown, the protective cap 30 is provided with a clearance opening 31 suitable for the needle 21 to pass through. For example, the needle 21 is connected to the needle seat 20 through the mounting body 211. The diameter of the mounting body 211 is larger than the diameter of the needle seat 20. The mounting body 211 is suitable for passing through the clearance opening 31.

[0049] Reference Figure 2 and Figure 5 As shown, the protective cap 30 is fitted over the needle holder 20, and the protective cap 30 and the needle holder 20 are in sliding engagement. The protective cap 30 is oriented along the axial direction of the needle holder 20 (refer to...). Figure 2 The needle can move between the exposed needle position and the protective position (in the left and right directions). In the exposed needle position (refer to...) Figure 10 The needle 21 passes through the clearance opening 31 and extends out of the protective cap 30; in the protective position (refer to...) Figure 11 The needle 21 is located inside the protective cap 30, and the needle 21 is opposite to the clearance opening 31 in the axial direction of the mounting part 11.

[0050] It is understood that, according to the embodiments of the present invention, the insulin pen 100, by providing a movable protective cap 30, allows the protective cap 30 to be adjusted to the needle-exposed position during insulin injection so that the needle 21 protrudes; after the insulin injection is completed, the protective cap 30 can be moved to the protective position to retract the needle 21 into the protective cap 30, and then the needle holder 20 and the protective cap 30 can be detached from the pen body 10 as a whole. Thus, after the insulin pen 100 has completed injection, needle 21 puncture injury can be avoided, and there is no need to reattach the pen cap 50. At the same time, it can meet clinical nursing needs and nursing regulations, which is conducive to ensuring the safe use of the insulin pen 100.

[0051] In some embodiments of the present invention, reference is made to... Figure 7 and Figure 8 As shown, the needle holder 20 is provided with a sliding groove 23, which includes a first groove segment 231 and a second groove segment 232. The first groove segment 231 extends along the length of the mounting portion 11. One end of the second groove segment 232 is connected to the end of the first groove segment 231 facing away from the needle 21. The other end of the second groove segment 232 extends along the circumferential direction of the insulin pen 100. The protective cap 30 is provided with a sliding block 32 (see reference). Figure 9 The sliding block 32 is adapted to slide in conjunction with the first groove segment 231 and the second groove segment 232.

[0052] It is understandable that by making the sliding groove 23 have a first groove segment 231 and a second groove segment 232, when the protective cap 30 is in the exposed pin position, rotating the protective cap 30 can switch the protective cap 30 between the locked and unlocked states, as shown in the reference. Figure 9 As shown, the sliding block 32 is located at the other end of the second groove segment 232, and the protective cap 30 is in a locked state; refer to Figure 10 As shown, the sliding block 32 is located at the end of the second groove 232 connected to the first groove 231. The protective cap 30 is in the unlocked state. At this time, the sliding block 32 can slide along the first groove 231 to move the protective cap 30 to the protective position (see reference). Figure 11 ).

[0053] In some embodiments of the present invention, reference is made to... Figure 9 and Figure 10 As shown, the insulin pen 100 also includes a needle ejection mechanism 40, which includes a locking assembly 41 and an elastic member 42. The locking assembly 41 is disposed between the needle holder 20 and the mounting portion 11 to lock or unlock the needle holder 20. The elastic member 42 is disposed between the needle holder 20 and the mounting portion 11, and extends along the axial direction of the mounting portion 11 and is normally in a compressed state. When the protective cap 30 is in the protective position, the locking assembly 41 is adapted to unlock the needle holder 20 so that the protective cap 30 and the needle holder 20 are ejected under the action of the elastic member 42 (see reference 11 and 12). Figure 12 For example, lock assembly 41 can be an electromagnetic lock or a manual lock.

[0054] Understandably, when the protective cap 30 is in the protective position, the locking assembly 41 can be controlled to unlock the needle holder 20 so that the protective cap 30 and the needle holder 20 can pop out together under the action of the elastic member 42, thereby facilitating the separation of the needle holder 20 from the mounting part 11; after a new needle holder 20 and protective cap 30 are installed, the locking assembly 41 locks the needle holder 20 and the mounting part 11, thereby facilitating the reliable installation of the needle holder 20.

[0055] In some embodiments of the present invention, reference is made to... Figure 5 and Figure 6 As shown, the free end of the mounting portion 11 is provided with an annular protrusion 12, which defines the liquid outlet of the pen body 10. The liquid outlet communicates with the needle 21. The elastic element 42 is located between the annular protrusion 12 and the inner wall of the mounting cavity 22 and extends along the axial direction of the mounting portion 11. One end of the elastic element 42 is connected to the inner wall of the mounting cavity 22, and the other end of the elastic element 42 is connected to the mounting portion 11. It can be understood that by providing the annular protrusion 12, reliable positioning of the elastic element 42 can be achieved, which is beneficial to ensuring the reliability of the operation of the elastic element 42.

[0056] Optionally, the elastic element 42 is a ring spring, which surrounds the annular protrusion 12. Thus, the annular protrusion 12 can act as a guide post, which helps to further ensure the reliability of the operation of the elastic element 42.

[0057] Or, refer to Figure 5 and Figure 6 As shown, there are multiple elastic elements 42, which are arranged at intervals in the circumferential direction of the annular protrusion 12, and each spring has a guide post at its center.

[0058] In some embodiments of the present invention, reference is made to... Figure 5 and Figure 6 As shown, one end of the elastic element 42 is bonded to the inner wall of the mounting cavity 22, and the other end of the elastic element 42 abuts against the mounting portion 11. It can be understood that when the protective cap 30 and the needle holder 20 are ejected under the action of the elastic element 42, the elastic element 42 ejects along with the protective cap 30 and the needle holder 20; or, one end of the elastic element 42 abuts against the inner wall of the mounting cavity 22, and the other end of the elastic element 42 is bonded to the mounting portion 11. It can be understood that when the protective cap 30 and the needle holder 20 are ejected under the action of the elastic element 42, the elastic element 42 remains on the needle holder 20. Therefore, the structure is simple and facilitates the reliable ejection of the needle holder 20.

[0059] In some embodiments of the present invention, reference is made to... Figure 5 and Figure 6 As shown, the lock assembly 41 includes a spring member 411 and a latch 412. The outer peripheral wall of the mounting part 11 is provided with a mounting groove 13 suitable for mounting the spring member 411 and the latch 412. The spring member 411 is connected between the bottom wall of the mounting groove 13 and the latch 412. This structure makes the lock assembly 41 easy and reliable to operate.

[0060] In some embodiments of the present invention, reference is made to... Figure 5 As shown, the needle ejection mechanism 40 also includes a sliding post 43 and a sliding button 44, and the needle holder 20 is provided with a mating hole 24 in the radial direction of the needle holder 20 (see reference). Figure 7 and Figure 8 The sliding post 43 is slidably engaged with the mating hole 24. The protective cap 30 is also provided with a sliding button 44 suitable for moving in the radial direction of the protective cap 30. When the protective cap 30 is in the protective position, the sliding button 44, the sliding post 43, and the latch 412 are opposite each other in the radial direction of the mounting part 11 (see reference). Figure 11 and Figure 12 ).

[0061] For example, such as Figure 5As shown, the protective cap 30 has a sliding hole 33 extending through the protective cap 30 in the radial direction. The sliding button 44 is slidably engaged with the sliding hole 33. Optionally, one end of the sliding hole 33 opposite to the mounting portion 11 is provided with a stop portion suitable for preventing the sliding button 44 from dislodging. This ensures the reliability of the operation of the sliding button 44.

[0062] Understandably, after the injection is completed, the protective cap 30 can be moved from the exposed needle position to the protective position. In the protective position, the sliding button 44 can be pressed to drive the sliding column 43 to push the locking buckle 412, thereby disengaging the locking buckle 412 from the needle holder 20. Under the elastic force of the elastic element 42, the needle holder 20 and the protective cap 30 pop out together. The operation is convenient and the reliability is high.

[0063] In some embodiments of the present invention, reference is made to... Figure 14 As shown, the side of the latch 412 facing away from the spring has a hemispherical portion 413, and the end of the needle holder 20 facing the pen body 10 has a guide surface 34, in the direction from the pen body 10 to the needle 21 (refer to...). Figure 2 (From right to left) The guide surface 34 extends obliquely toward the axis of the needle holder 20. It can be understood that by providing a guide surface 34 in the needle holder 20 that is suitable for engaging with the hemispherical portion 413, the guide surface 34 can press the latch 412 into the mounting groove 13 when the needle holder 20 is installed, thereby facilitating the installation of the needle holder 20.

[0064] In some embodiments of the present invention, reference is made to... Figure 3 As shown, there are two mounting slots 13, which are arranged opposite each other in the radial direction of the mounting portion 11. There are also two needle ejection mechanisms 40, which are arranged one-to-one with the two mounting slots 13. It can be understood that by providing two needle ejection mechanisms 40 arranged opposite each other in the radial direction of the mounting portion 11, it is beneficial to further ensure the reliable ejection of the needle holder 20, thereby ensuring the reliable operation of the insulin pen 100.

[0065] In some embodiments of the present invention, reference is made to... Figure 5 As shown, the insulin pen 100 also includes a pen cap 50, which is adapted to engage with a protective cap 30 to define a receiving space, within which the needle 21 is located. Therefore, by placing the pen cap 50 over the protective cap 30, it is beneficial to prevent the needle 21 from being contaminated by external dust or other debris, thus ensuring safe injection.

[0066] In a specific example of the present invention, refer to Figures 9-13 As shown, the operation of insulin pen 100 can be performed as follows:

[0067] Reference Figure 9As shown, when the insulin pen 100 is not in use, the pen cap 50 and the protective cap 30 are engaged, the protective cap 30 is in the needle-exposed position, the needle 21 is in the receiving space, at this time, the sliding block 32 is at the other end of the second groove 232, and the protective cap 30 is in the locked state.

[0068] Reference Figure 10 As shown, before insulin injection, remove the pen cap 50 for injection. After injection, rotate the protective cap 30 a certain angle along the extension direction of the second groove 232 to switch to the unlocked state. Then move the protective cap 30 so that the sliding block 32 slides along the first groove 231 (refer to...). Figure 11 This causes the protective cap 30 to move from the exposed needle position to the protective position;

[0069] Reference Figure 12 and Figure 13 As shown, pressing the two sliding buttons 44 unlocks the needle holder 20, causing the protective cap 30 and the needle holder 20 to pop out under the action of the elastic element 42. When needed for the next use, a new needle holder 20, protective cap 30, and pen cap 50 can be installed. Thus, after the insulin pen 100 has finished injecting, needle 21 punctures can be avoided, and there is no need to re-attach the pen cap 50. This meets clinical nursing needs and regulations, and helps ensure the hygiene and safety of the insulin pen 100.

[0070] Other structures and operations of the insulin pen 100 according to embodiments of the present invention are known to those skilled in the art and will not be described in detail here.

[0071] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" 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 this 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. Therefore, they should not be construed as limitations on this invention.

[0072] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0073] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0074] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0075] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "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 present 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. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0076] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. An insulin injection pen, characterized in that The application relates to an insulin injection pen, comprising: a pen body, one end of the pen body being provided with a mounting portion; a needle seat, one end of the needle seat being provided with a needle, the other end of the needle seat being provided with a mounting cavity adapted to detachably cooperate with the mounting portion; a protective cap, the protective cap being provided with an avoiding opening adapted to allow the needle to pass through, the protective cap being sleeved on the needle seat, the protective cap and the needle seat being in sliding cooperation, the protective cap being movable along the axial direction of the needle seat between a needle-exposed position and a protective position, in the needle-exposed position, the needle passes through the avoiding opening and extends out of the protective cap, in the protective position, the needle is located in the protective cap; a needle-ejection mechanism, the needle-ejection mechanism comprising a lock assembly and an elastic member, the lock assembly being arranged between the needle seat and the mounting portion to lock or unlock the needle seat, the elastic member being arranged between the needle seat and the mounting portion, the elastic member extending along the axial direction of the mounting portion and being always in a compressed state, when the protective cap is in the protective position, the lock assembly is adapted to unlock the needle seat so that the protective cap and the needle seat are ejected under the action of the elastic member; wherein the needle seat is provided with a sliding groove, the sliding groove comprising a first groove segment and a second groove segment, the first groove segment extending along the length direction of the mounting portion, one end of the second groove segment being connected with the end of the first groove segment away from the needle, the other end of the second groove segment extending along the circumferential direction of the insulin injection pen, the protective cap being provided with a sliding block, the sliding block being adapted to slide with the first groove segment and the second groove segment; wherein the lock assembly comprises a spring member and a lock buckle, the outer peripheral wall of the mounting portion being provided with a mounting groove adapted to mount the spring member and the lock buckle, the spring member being connected between the bottom wall of the mounting groove and the lock buckle; wherein the needle-ejection mechanism further comprises a sliding column and a sliding button, the needle seat being provided with a cooperating hole in the radial direction of the needle seat, the sliding column being in sliding cooperation with the cooperating hole, the protective cap being further provided with a sliding button adapted to move along the radial direction of the protective cap, when the protective cap is in the protective position, the sliding button, the sliding column and the lock buckle are opposite in the radial direction of the mounting portion; wherein the side of the lock buckle away from the spring member is provided with a hemispherical portion, one end of the needle seat towards the pen body is provided with a guide surface, in the direction from the pen body to the needle, the guide surface extends in the direction of being close to the axis of the needle seat.

2. The insulin injection pen of claim 1, wherein the free end of the mounting portion is provided with an annular protrusion, the annular protrusion defining a liquid outlet of the pen body, the liquid outlet being in communication with the needle, the elastic member being located between the annular protrusion and the inner wall of the mounting cavity and extending along the axial direction of the mounting portion, one end of the elastic member being connected with the inner wall of the mounting cavity, the other end of the elastic member being connected with the mounting portion.

3. The insulin injection pen of claim 2, wherein, One end of the elastic member is bonded to the inner wall of the mounting cavity, and the other end of the elastic member abuts against the mounting portion, or one end of the elastic member abuts against the inner wall of the mounting cavity, and the other end of the elastic member is bonded to the mounting portion.

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