Two-step injection pen

Abstract

The invention belongs to the technical field of injection pens, and particularly relates to a two-step injection pen. A two-step type injection pen comprises a pushing piece, a first groove part and a second groove part are formed in the outer wall of the pushing piece; the excitation piece is arranged on the outer wall of the propelling piece in a sleeving manner and comprises a first elastic tongue part; the limiting guide piece can axially and movably sleeve the outer wall of the excitation piece; the locking piece is axially and movably arranged between the excitation piece and the limiting guide piece; the needle head sleeve is axially and movably arranged in the pen body, and the lower end of the needle head sleeve abuts against the limiting guide piece; when the first elastic tongue part is not excited, the first elastic tongue part is clamped into the limiting guide part and is limited in the limiting guide part in the radial direction, and the first elastic tongue part is clamped into the first groove part. During excitation, the needle sleeve pushes the limiting guide piece and the locking piece to move in the direction away from the needle; after the first elastic tongue part is separated from the limit, the first elastic tongue part is separated from the first groove part, so that the pushing piece moves towards the needle head; after injection is completed, the first elastic tongue part is clamped into the second groove part.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of injection pens, and particularly relates to a two-step injection pen. BACKGROUND

[0002] As a kind of drug delivery device aiming at simplifying operation and improving user experience, the two-step injection pen is designed to automatically complete the whole process of needle ejection, drug injection and needle recovery / protection through "pressing to trigger".

[0003] However, the existing two-step injection pen generally has problems such as complex structure, poor part stability, difficult assembly and the like. The triggering and locking mechanism is mainly composed of independent and complicated components, resulting in bulky overall structure and low reliability. The key elastic buckle is easily damaged during installation due to defects in the structure of the injection pen, and the elastic structure is prone to interference with adjacent parts during movement, causing action jamming.

[0004] Therefore, how to solve the problem of elastic structure interference with adjacent parts and causing action jamming is a technical problem urgently to be solved in the field.

[0005] It should be noted that the above information disclosed in the background section is only used to understand the background of the present application, and therefore, the above description is not considered to constitute relevant information of the prior art. SUMMARY

[0006] The present application provides at least a two-step injection pen.

[0007] The present application provides a two-step injection pen, comprising: a pusher movably arranged in the pen body in an axial direction, and having a first slot and a second slot formed in the outer wall thereof; a trigger member sleeved on the outer wall of the pusher and comprising a first elastic tongue; a limiting guide member movably arranged on the outer wall of the trigger member in an axial direction; a locking member movably arranged between the trigger member and the limiting guide member in an axial direction; a needle sleeve movably arranged in the pen body in an axial direction, and having a lower end abutting against the limiting guide member; wherein, when not triggered, the first elastic tongue is radially limited in the limiting guide member and clamped into the first slot; when triggered, the needle sleeve pushes the limiting guide member and the locking member to move away from the needle; after the first elastic tongue is disengaged from the limiting guide member, the first elastic tongue is disengaged from the first slot, and the pusher moves towards the needle; after the injection is completed, the first elastic tongue is clamped into the second slot.

[0008] In an alternative embodiment, further comprising: a reset spring arranged between the limiting guide and the locking member; and a locking step symmetrically arranged inside the limiting guide; A second elastic tongue is arranged on the locking member and slidably arranged inside the limiting guide; When activated, the limiting guide moves away from the needle, and the reset spring is in a compressed state; After injection, the reset spring pushes the limiting guide to move towards the needle, and the second elastic tongue abuts against the locking step.

[0009] In an alternative embodiment, the inner wall of the limiting guide is circumferentially spaced apart with a first guide groove and a second guide groove; When not activated, the first elastic tongue abuts against the groove wall of the first guide groove, and the second elastic tongue abuts against the groove wall of the second guide groove.

[0010] In an alternative embodiment, the first guide groove is formed with a first step protruding inwardly; When not activated, the first elastic tongue is clamped between the first step and the first groove.

[0011] In an alternative embodiment, the second guide groove is formed with a second step protruding inwardly; The activation member includes an activation sleeve, and a second guide groove is further arranged on the sleeve wall of the activation sleeve, The locking member is slidably arranged on the outer wall of the activation sleeve, and the second elastic tongue is accommodated in the second guide groove; When not activated, the second elastic tongue is clamped between the second step and the second guide groove; When activated, the second elastic tongue axially slides along the second guide groove.

[0012] In an alternative embodiment, the lower end of the activation sleeve is provided with an annular wall step; The locking member includes a locking sleeve; When injection is completed, the second elastic tongue is disengaged from the abutment with the advancing member, and the reset spring pushes the locking sleeve to axially move away from the needle to impact the annular wall step to make a sound.

[0013] In an alternative embodiment, the lower end of the advancing member is symmetrically provided with two bosses; The inner wall of the activation member is symmetrically provided with two first guide grooves along the axial direction, and one first guide groove corresponds to one boss; The first guide groove is provided with a stop step near the first elastic tongue end; The stop step is in abutment with the boss.

[0014] In an alternative embodiment, a lower inclined surface is formed in the inner wall of the lower end of the limiting guide, and the included angle between the lower inclined surface and the axis of the limiting guide is 10-20°. The lower inclined surface is adapted to guide the insertion of the first elastic tongue into the limiting guide.

[0015] In an alternative embodiment, an upper inclined surface is formed in the inner wall of the upper end of the limiting guide, and the included angle between the upper inclined surface and the axis of the limiting guide is 40-50°. The upper inclined surface is adapted to guide the ejection of the first elastic tongue from the limiting guide.

[0016] In an alternative embodiment, two inclined blocks are symmetrically arranged on the outer wall of the annular wall platform. The bottom of the pen body is provided with a plunger guide rod, and the inner wall of the plunger guide rod is provided with a positioning groove matched with the inclined blocks. When the plunger guide rod is inserted between the pen body and the annular wall platform, the inclined blocks are inserted into the positioning groove.

[0017] The beneficial effects of the present application are that the present application provides a two-step injection pen, which integrates core components such as a trigger, a limiting guide, and a propelling member, optimizes the cooperation mechanism of the elastic tongue and the groove, and avoids the structural bulkiness problem caused by multiple independent components in traditional designs. The elastic tongue adopts a symmetrical design and an interference fit, combined with the guide groove on the limiting guide, effectively preventing interference and jamming during movement, and improving the smoothness and reliability of the action.

[0018] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art from the description, or can be learned by practice of the present application. The objects and other advantages of the present application will be realized and achieved by the structures particularly pointed out in the description and the appended drawings.

[0019] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the preferred embodiments are described in detail below, and the accompanying drawings are described as follows. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the specific embodiments or related art, the following will briefly introduce the drawings needed to be used in the specific embodiments or related art description. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creating any inventive labor.

[0021] Figure 1 Internal development schematic view of the two-step injection pen provided by the embodiment of the present disclosure; Figure 2 Internal perspective view of the two-step injection pen provided by the embodiment of the present disclosure; Figure 3 Perspective view of the pusher provided by the embodiment of the present disclosure; Figure 4 Axial sectional perspective view of the trigger and the pusher provided by the embodiment of the present disclosure; Figure 5 Axial sectional view of the limit guide provided by the embodiment of the present disclosure; Figure 6 Axial sectional perspective view of the two-step injection pen provided by the embodiment of the present disclosure; Figure 7 Axial sectional view of the trigger and the lock provided by the embodiment of the present disclosure.

[0022] In the figure: 1, pen body; 11, plunger guide rod; 12, positioning groove; 2, pusher; 21, first groove part; 22, second groove part; 23, boss; 24, trigger spring; 3, trigger; 30, first elastic tongue part; 31, first guide groove; 32, stop step; 33, annular wall platform; 34, inclined block; 35, trigger sleeve; 36, second guide groove; 4, limit guide; 40, locking step; 42, lower inclined surface; 43, upper inclined surface; 44, first guide groove; 45, second guide groove; 46, first step; 47, second step; 5, needle sleeve; 6, lock; 61, second elastic tongue part; 62, locking sleeve; 7, reset spring. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme of the present application will be described clearly and completely below with reference to the drawings. Obviously, the described embodiments are some of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0024] In this document, when referred to as a first component being on a second component, it can mean that the first component can be directly formed on the second component, or a third component can be interposed between the first component and the second component. Also, in the drawings, the thickness of components can be exaggerated or reduced for effective description of the technical idea.

[0025] In this document, example embodiments of the present disclosure will be described in greater detail with reference to the accompanying drawings. As used herein, expressions such as "at least one of," when preceded by terms introducing a list of elements such as "…a, b, and c," modifies the entire list of elements and do not modify the individual elements of the list. For example, the expression "at least one of a, b, and c" should be understood as including only a, only b, only c, both a and b, both a and c, both b and c, or all of a, b, and c.

[0026] The terminology used herein is for the purpose of describing particular example configurations only and is not intended to be limiting. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises," "comprising," "includes," and "including" are inclusive and therefore specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order in which they are discussed or illustrated, unless specifically identified as an order of performance. Additional or alternative steps can be employed.

[0027] As used herein, the phrases "in an embodiment," "according to an embodiment," "in some embodiments," and the like generally mean the particular feature, structure, or characteristic following the phrase can be included in at least one embodiment of the present disclosure. Thus, appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. As used herein, the term "example" or "exemplary" means "serving as an example, instance, or illustration." Any implementation, aspect, or design described herein as "example" or "exemplary" is not necessarily to be construed as preferred or advantageous over other implementations, aspects, or designs. Rather, the term "example" or "exemplary" is intended to present concepts in a concrete manner. In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments can be practiced without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

[0028] It is found through research that the two-step injection pen, as a drug delivery device aiming to simplify the operation and improve the user experience, its design concept is to automatically complete the whole process of needle ejection, drug injection and needle recycling / protection through the "press-to-trigger" mode.

[0029] However, the existing two-step injection pen has the problems of complex structure, poor part stability, difficult assembly and the like. The triggering and locking mechanism is composed of independent and complicated components, resulting in bulky overall structure and low reliability. The key elastic buckle is easily damaged during installation due to defects in the structure of the injection pen, and the elastic structure is easily interfered with the adjacent components during movement, causing action jam.

[0030] Therefore, how to solve the problem of elastic structure easily interfering with adjacent components and causing action jam is a technical problem urgently to be solved in the field.

[0031] The defects of the above-mentioned solutions and the causes thereof are the results of the inventors after practice and careful research, and therefore, the discovery process of the above-mentioned problems and the solutions proposed by the present disclosure to solve the above-mentioned problems should be the contributions of the inventors to the present disclosure in the process of the present disclosure.

[0032] It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0033] Some embodiments of the present application will be described in detail below with reference to the accompanying drawings. The following embodiments and features in the embodiments can be combined with each other without conflict.

[0034] As shown in Figure 1 At least one embodiment of the two-step injection pen can include a pusher 2 which is axially movably arranged in the pen body 1, and the outer wall of which is provided with a first slot portion 21 and a second slot portion 22.

[0035] The distance between the second slot portion 22 and the first slot portion 21 is adjustable, and the axial distance between the second slot portion 22 and the first slot portion 21 can be adjusted according to the height of the medicine bottle in the pen body 1. The lower end of the pusher 2 is symmetrically provided with two bosses 23, and an activation spring 24 is arranged inside. The activation spring 24 is used to push the pusher 2 to move axially towards the needle direction. The specific structure of the pusher 2 is shown in Figure 3

[0036] Referring to the accompanying Figure 4 , the trigger 3 is sleeved on the outer wall of the pusher 2 and includes a first elastic tongue portion 30. The inner end of each first elastic tongue portion 30 is adapted to be clamped into the first slot portion 21. The first elastic tongue portion 30 can be clamped into the first slot portion 21 or the second slot portion 22. Two first guide grooves 31 are symmetrically arranged on the inner wall of the trigger 3 along the axial direction, and a stop step 32 is arranged at the end of the first elastic tongue portion 30. An annular wall table 33 is arranged on the bottom wall of the trigger 3, and two inclined blocks 34 are symmetrically arranged on the outer wall of the annular wall table 33. The assembly relationship between the trigger 3 and the pusher 2 is shown in​Figure 4 as shown.

[0037] Reference is made to the accompanying drawings Figure 5 A limiting guide 4 is axially movably sleeved on the outer wall of the activating member 3. A lower inclined surface 42 is formed on the inner wall of the lower end of the limiting guide 4. The inclined angle between the lower inclined surface 42 and the axis of the limiting guide 4 is 10°-20°. Preferably, the inclined angle is 15°. The lower inclined surface 42 is adapted to guide the insertion of the first elastic tongue 30 into the limiting guide 4. An upper inclined surface 43 is formed on the inner wall of the upper end of the limiting guide 4. The inclined angle between the upper inclined surface 43 and the axis of the limiting guide 4 is 40°-50°. Preferably, the inclined angle is 45°. The upper inclined surface 43 is adapted to guide the ejection of the first elastic tongue 30 out of the limiting guide 4.

[0038] The inner wall of the limiting guide 4 is axially spaced apart with a first guide groove 44 and a second guide groove 45. The first guide groove 44 is formed with a first step 46 protruding inwardly. The second guide groove 45 is formed with a second step 47 protruding inwardly. When not activated, the first elastic tongue 30 abuts against the groove wall of the first guide groove 44, and the second elastic tongue 61 abuts against the groove wall of the second guide groove 45.

[0039] Reference is made to the accompanying drawings Figure 2 A needle sleeve 5 is axially movably arranged in the pen body 1 and abuts against the limiting guide 4 at the lower end. The needle sleeve 5 can push the limiting guide 4 to move synchronously when the needle sleeve 5 moves axially.

[0040] Reference is made to the accompanying drawings Figure 2 A locking member 6 is axially movably arranged between the activating member 3 and the limiting guide 4. A second elastic tongue 61 is arranged on the locking member 6 and is slidingly arranged inside the limiting guide 4. A locking sleeve 62 is arranged at the bottom of the locking member 6. The cooperating relationship between the activating member 3 and the locking member 6 is shown in Figure 7 .

[0041] When not activated, the first elastic tongue 30 is clamped into the first groove portion 21, i.e. the first elastic tongue 30 is clamped between the first step 46 and the first groove portion 21. When activated, the needle sleeve 5 pushes the limiting guide 4 and the locking member 6 to move away from the needle direction, and the first elastic tongue 30 is ejected out of the first groove portion 21 after being released from the limiting guide 4, so as to move the advancing member 2 towards the needle direction. After injection, the first elastic tongue 30 is clamped into the second groove portion 22.

[0042] Specifically, when not triggered, the first elastic tongue 30 is clamped into the first slot 21, which is a limiting slot, and functions to limit the first elastic tongue 30. After injection is completed, the first elastic tongue 30 is clamped into the second slot 22, which is an avoidance slot at this time, and when the first elastic tongue 30 is clamped into the second slot 22, the limiting guide 4 outside the triggering piece 3 can move to the needle direction to shield the exposed needle. The design of the second slot 22 can effectively prevent the limiting guide 4 and the first elastic tongue 30 from interfering in movement during the reset of the needle sleeve 5.

[0043] Reference is made to the accompanying drawings Figure 6 The bottom of the pen body 1 is provided with a plunger guide rod 11, and the inner wall is provided with a positioning slot 12 matched with the inclined block 34. The needle sleeve 5 is axially movably arranged in the pen body 1 and abuts against the limiting guide 4 at the lower end. The internal expansion schematic view of the injection pen is shown in Figure 1 , and the axial sectional view is shown in Figure 6 .

[0044] The working process is as follows: The standby state is shown in Figure 5 and Figure 6 When not triggered, the step structure of the limiting guide 4 (i.e. the inner wall of the first guide slot 44) abuts against the outer end of the first elastic tongue 30, and the inner end of the first elastic tongue 30 is clamped into the first slot 21 of the advancing piece 2, thereby limiting the advancing piece 2. At the same time, the outer end of the second elastic tongue 61 abuts against the inner wall of the second guide slot 45 of the limiting guide 4, and the inner end abuts against the advancing piece 2, forming a stable lock.

[0045] As shown in Figure 4 , when the needle sleeve 5 contacts the skin and is pressed downward, the needle sleeve 5 pushes the limiting guide 4 to move away from the needle direction (distal end). The upper inclined surface 43 of the limiting guide 4 guides the outer end of the first elastic tongue 30 to disengage from the first guide slot 44, and after the radial limiting is released, the inner end of the first elastic tongue 30 is disengaged from the first slot 21. Thus, the advancing piece 2 moves to the needle direction (proximal end) under the action of the triggering spring 24, and the drug injection is completed. At this time, the first elastic tongue 30 is clamped into the second slot 22, which provides an avoidance space for the next movement of the limiting guide 4 to the needle direction, so as to avoid interference.

[0046] When the advancing piece 2 moves to the injection completion, the boss 23 abuts against the stop step 32 of the triggering piece 3. At the same time, the second elastic tongue 61 no longer abuts against the outer wall of the advancing piece 2, and thus the second elastic tongue 61 is disengaged from the step limiting of the limiting guide 4. The spring of the needle sleeve 5 is released, the locking piece 6 is pushed to move to the distal end, the locking sleeve 62 hits the annular wall step 33 to make a sound, and the injection completion is prompted.

[0047] The needle sleeve spring then pushes the limit guide 4 to move in the needle direction, thus pushing the needle sleeve 5 to move in the needle direction, covering the exposed needle, preventing injury to the patient or others.

[0048] Reference to the attached drawings Figure 5 The bottom of the activation sleeve 35 is provided with an annular wall platform 32, and the outer wall of the annular wall platform 32 at the bottom of the activation member 3 is symmetrically provided with two inclined blocks 33 with an inclination angle of 15°-30°, which are adapted with the positioning groove 42 on the inner wall of the plunger guide rod 41 at the bottom of the pen body 4. During assembly, the inclined blocks 33 are inserted into the positioning groove 42 to form a circumferential locking to prevent the rotation of the activation member 3. The assembly process is as follows: First, the operator inserts the advancing member 2 and the activation spring 24 into the activation member 3 from below, and the boss 23 on the outer wall of the advancing member 2 is inserted into the first guide groove 31 on the inner wall of the activation member 3. At the same time, the first slot part 21 of the advancing member 2 is clamped with the first elastic tongue part 30.

[0049] Secondly, the operator assembles the advancing member 2, the activation spring 24 and the activation member 3 into the pen body 1. Then the plunger guide rod 11 is inserted into the pen body 1, and the inclined blocks 34 of the annular wall platform 33 are clamped into the positioning groove 12 for fixation.

[0050] Then, the operator puts the locking member 6 on the outer wall of the activation member 3, and the second elastic tongue part 61 is accommodated in the second guide groove 36 of the activation sleeve 35. After that, the reset spring 7 and the limit guide 4 are sequentially reset, and the activation spring 24 and the reset spring are compressed to the standby position.

[0051] In the standby position, the first elastic tongue part 30 is radially limited between the first step 46 of the limit guide 4 and the first slot part 21 of the advancing member. At the same time, the second elastic tongue part 61 is radially limited between the second step 47 of the limit guide 4 and the end of the second guide groove 36, and abuts against the advancing member 2 inwardly. These two structures together stabilize the injection pen in the safe standby state without activation.

[0052] Here, it needs to be supplemented that the boss 23 on the outer wall of the advancing member 2 is inserted into the first guide groove 31 on the inner wall of the activation member 3. In case of accidental activation, the boss 23 and the stop step 32 at the end of the first guide groove 31 abut, which is used to prevent the advancing member 2 of the injection pen from being activated before the assembly of the medicine bottle or during transportation under the action of the advancing spring, so as to avoid the mechanical impact injury to the operator caused by the ejection of the advancing member 2.

[0053] The lower inclined surface 42 at the lower end of the limit guide 4 can guide the smooth assembly of the limit guide 4 relative to the first elastic tongue part 30 of the activation member 3.

[0054] In the description of the embodiments of the present application, unless specifically defined and limited otherwise, the terms "mounting", "connected", "connecting" should be understood broadly, for example, can be fixedly connected, can be detachably connected, or integrally connected; can be mechanically connected, can be electrically connected; can be directly connected, can be indirectly connected through an intermediate medium, can be internal communication of two elements. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0055] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, terms such as "first", "second" and other numerical terms are used herein and do not imply sequence or order unless expressly indicated herein. Therefore, the first element, component, region, layer or section discussed above can be referred to as the second element, component, region, layer or section without departing from the teachings of the example embodiments.

[0056] Based on the above ideal embodiments according to the present application, through the above description, relevant personnel can make various changes and modifications without deviating from the technical idea of the present application. The technical scope of the present application is not limited to the contents of the specification, and must be determined by the scope of the claims.

Claims

1. A two-step injection pen, characterized in that, include: The pusher (2) is axially movable inside the pen body (1) and has a first groove (21) and a second groove (22) on its outer wall. The excitation element (3) is sleeved on the outer wall of the propulsion element (2) and includes a first elastic tongue (30). A limiting guide (4) is axially movable and sleeved on the outer wall of the excitation element (3); The locking member (6) is axially movable between the actuating member (3) and the limiting guide member (4); The needle sleeve (5) is axially movable inside the pen body (1), and its lower end abuts against the limiting guide (4); When not activated, the first elastic tongue (30) is radially limited within the limiting guide and engages with the first groove (21). When activated, the needle sleeve (5) pushes the limiting guide (4) and the locking member (6) to move away from the needle. After the first elastic tongue (30) disengages from the radial limiting of the limiting guide (4), the first elastic tongue (30) disengages from the first groove (21), and the pusher (2) moves towards the needle. After the injection is completed, the first elastic tongue (30) is inserted into the second groove (22).

2. The two-step injection pen as described in claim 1, characterized in that, Also includes: A reset spring (7) is disposed between the limiting guide (4) and the locking member (6); the limiting guide (4) is symmetrically provided with locking steps (40) inside. The locking member (6) is provided with a second elastic tongue (61), which is slidably disposed inside the limiting guide member (4); During activation, the limiting guide (4) moves away from the needle tip, and the reset spring (7) is in a compressed state. After the injection is completed, the reset spring (7) pushes the limiting guide (4) to move towards the needle tip, and the second elastic tongue (61) abuts against the locking step (40).

3. The two-step injection pen as described in claim 2, characterized in that, The inner wall of the limiting guide (4) is provided with a first guide groove (44) and a second guide groove (45) spaced apart in the circumferential direction. When not activated, the first elastic tongue (30) abuts against the wall of the first guide groove (44), and the second elastic tongue (61) abuts against the wall of the second guide groove (45).

4. The two-step injection pen as described in claim 3, characterized in that, The first guide groove (44) has an inwardly protruding first step (46). In the unactivated state, the first elastic tongue (30) is engaged between the first step (46) and the first groove (21).

5. The two-step injection pen as described in claim 3, characterized in that, The second guide groove (45) has an inwardly protruding second step (47); The excitation element (3) includes an excitation sleeve (35), and a second guide groove (36) is provided on the sleeve wall of the excitation sleeve (35). The locking member (6) is slidably sleeved on the outer wall of the excitation sleeve (35), and the second elastic tongue (61) is accommodated in the second guide groove (36); In the unactivated state, the second elastic tongue (61) is engaged between the second step (47) and the second guide groove (36); When activated, the second elastic tongue (61) slides axially along the second guide groove (36).

6. The two-step injection pen as described in claim 5, characterized in that, The lower end of the excitation sleeve (35) is provided with an annular wall platform (33). The locking element (6) includes a locking sleeve (62); When the injection is completed, the second elastic tongue (61) disengages from the pusher (2), and the reset spring (7) pushes the locking sleeve (62) to move axially away from the needle and strike the annular wall (33) to produce a sound.

7. The two-step injection pen as described in claim 1, characterized in that, The lower end of the propulsion member (2) is symmetrically provided with two protrusions (23); The inner wall of the excitation element (3) is symmetrically provided with two first guide grooves (31) along the axial direction, and one first guide groove (31) corresponds to one boss (23). The first guide groove (31) is provided with a stop step (32) near the end of the first elastic tongue (30); The stop step (32) abuts against the boss (23).

8. The two-step injection pen as described in claim 1, characterized in that, The lower end of the limiting guide (4) has a lower inclined surface (42) on its inner wall, and the angle between the lower inclined surface (42) and the axis of the limiting guide (4) is 10°-20°. The lower slope (42) is adapted to guide the insertion of the first elastic tongue (30) into the limiting guide (4).

9. The two-step injection pen as described in claim 4, characterized in that, The upper inner wall of the limiting guide (4) has an upper inclined surface (43), and the angle between the upper inclined surface (43) and the axis of the limiting guide (4) is 40°-50°. The upper inclined surface (43) is adapted to guide the insertion or disengagement of the first elastic tongue (30) from the limiting guide (4).

10. The two-step injection pen as described in claim 6, characterized in that, Two inclined blocks (34) are symmetrically arranged on the outer wall of the annular platform (33). The bottom of the pen body (1) is provided with a plunger guide rod (11), and a positioning groove (12) adapted to the inclined block (34) is opened on its inner wall. When the plunger guide rod (11) is inserted between the pen body (1) and the annular wall platform (33), the inclined block (34) is inserted into the positioning groove (12).

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