Injection pen anti-fall structure and usage method thereof

Abstract

The present invention belongs to the field of medical technology, and in particular relates to an anti-drop structure for an injection pen and a method for using the same. The present invention provides an anti-drop structure for an injection pen, comprising: a graduated rotary drum, comprising a rotary drum body fitted with an inner liner, and a dosage scale knob fitted on the rotary drum body; a locking mechanism disposed within the dosage scale knob and comprising a locking tongue adapted to retract toward the inner liner; a limiting opening adapted to fit the locking tongue on the inner liner facing the dosage scale knob; and when in a stationary state, the locking tongue retracts and hooks into the limiting opening, thereby self-locking the dosage scale knob. Through the interaction of the inner liner, the graduated rotary drum, and the locking mechanism, when the graduated rotary drum rotates to zero, the locking mechanism can lock the graduated rotary drum, preventing it from rotating outward, thereby avoiding waste of medication within the pen barrel.

Description

Technical Field

[0001] The present invention belongs to the field of medical technology, and in particular relates to a syringe, and more particularly to an anti-fall structure of an injection pen and a method of using the same. Background Art

[0002] For chronic diseases, medical professionals and patients who self-inject medications at home often use injection pens to inject medications to achieve the purpose of treating chronic diseases. Pen-based medication treatments can be divided into diabetes treatment, growth hormone treatment, osteoporosis treatment, fertility treatment, and other treatments.

[0003] In the related art, there are many different types of injection pens that can achieve the effect of self-injection by patients. When in use, after rotating the scale drum to the specified scale, squeeze the button. The scale drum pushes the stopper to move horizontally while rotating to achieve the effect of quantitative injection.

[0004] However, because the graduated cylinder can rotate forward and backward at will, if the pen is dropped or impacted during storage, the graduated cylinder may rotate outward. Patients may then habitually press the button to return the graduated cylinder to zero. Since the graduated cylinder has already rotated outward a few notches, pressing the button directly at this point can cause the stopper to slide horizontally outward, wasting the amount of liquid in the vial.

[0005] Therefore, how to avoid wasting the liquid medicine in the medicine bottle caused by the scale drum rotating outward due to the injection pen falling or being hit by external force is a technical problem that needs to be solved urgently in this field.

[0006] It should be noted that the above information disclosed in this background technology section is only used to understand the background technology of the present application concept, and therefore, the above description is not considered to constitute information of the prior art. Summary of the Invention

[0007] The embodiments of the present disclosure at least provide an anti-fall structure for an injection pen and a method for using the same.

[0008] In a first aspect, an embodiment of the present disclosure provides an anti-drop structure for an injection pen, comprising:

[0009] The graduated rotary drum comprises a rotary drum body provided with an inner lining, and a dosage graduated knob fixed on the rotary drum body;

[0010] A locking mechanism is slidably disposed inside the dosage scale knob and includes a locking tongue facing the lining side and adapted to retract;

[0011] The inner lining is provided with a limit opening adapted to the lock tongue on the side facing the dosage scale knob;

[0012] When in a stationary state, the lock tongue retracts and hooks the limit mouth, and the scale knob is used for self-locking.

[0013] In an optional embodiment, the locking mechanism includes: a connecting rod, which passes through the dosage scale knob and has an outer end abutting against a button, and the button is slidably arranged on the outer end of the dosage scale knob;

[0014] The locking tongue is arranged at the inner end portion of the connecting rod;

[0015] The button pushes the dosage scale knob to slide inward, and the locking tongue is suitable for abutting against the side wall of the limiting opening.

[0016] In an optional embodiment, a locking groove is provided on the inner wall of the limiting opening;

[0017] The locking tongue includes: a limiting block, which is arranged at the inner end of the connecting rod;

[0018] A locking block, which is arranged on the side wall of the limiting block, and the locking block is adapted to the locking groove;

[0019] Wherein, when the limiting block abuts against the inner wall of the limiting opening, the locking block is suitable for being inserted into the locking groove.

[0020] In an optional embodiment, the length of the locking block is smaller than the slot length of the locking slot;

[0021] Wherein, in the static state, the locking block is inserted into the locking groove so that the locking tongue is self-locking.

[0022] In an optional embodiment, a protrusion is provided on a side of the locking block close to the connecting rod;

[0023] The inner wall of the locking groove is provided with a limiting groove adapted to the protrusion;

[0024] Wherein, when the limiting block abuts against the side wall of the limiting opening, the protrusion is adapted to be inserted into the limiting groove so as to rotate the limiting dosage scale knob in the opposite direction.

[0025] In an optional embodiment, an air channel is provided on the outer wall of the button along the axial direction, the air channel is adapted to the connecting rod, and an air outlet of the air channel is located between the button and the dosage scale knob;

[0026] When the button pushes the connecting rod to move toward the lining, the outer end of the connecting rod is inserted into the airway, so that the air in the airway flows outward to clean the dust between the button and the dosage scale knob.

[0027] In a second aspect, the present disclosure also provides an injection pen, comprising:

[0028] The pen body has an observation window on its outer wall;

[0029] The inner lining is arranged in the pen body and has a through hole corresponding to the observation window;

[0030] a graduated rotary drum, which is rotatably arranged inside the liner;

[0031] The scale drum comprises: a drum body, which is adapted to the inner lining thread,

[0032] and a dosage scale knob sleeved on the drum body;

[0033] a button slidably disposed on the end of the dosage scale knob;

[0034] A locking mechanism is slidably disposed inside the dosage scale knob and is linked to the button;

[0035] After the rotating drum body rotates outward to a predetermined scale, the button pushes the graduated rotating drum to rotate inward, thereby pushing the rubber plug in the pen barrel toward the liquid outlet;

[0036] In a stationary state, the locking tongue of the locking mechanism is inserted into a limiting opening provided on the side wall of the lining so as to be self-locked using the measuring scale knob.

[0037] In an optional embodiment, the locking mechanism includes: a connecting rod, which passes through the dosage scale knob and has an outer end abutting against the button;

[0038] a locking tongue, which is arranged at the inner end of the connecting rod and is suitable for being inserted into the limiting opening;

[0039] The locking tongue includes: a limiting block, which is arranged at the inner end of the connecting rod;

[0040] A locking block, which is arranged on the side wall of the limiting block, and is suitable for being inserted into the locking groove on the inner wall of the limiting opening;

[0041] The button pushes the dosage scale knob to slide inward until the limit block abuts against the inner wall of the limit opening, and the locking block is suitable for being inserted into the locking groove.

[0042] In an optional embodiment, the length of the locking block is smaller than the slot length of the locking slot;

[0043] Wherein, in the static state, the locking block is inserted into the locking groove so that the lock tongue is self-locking;

[0044] When injection is required, the button pushes the connecting rod to disengage the locking block from the locking groove;

[0045] The dosage scale knob is rotated outward to a predetermined scale, and the button pushes the dosage scale knob to rotate inward, so as to push the rubber plug in the pen body barrel to move toward the liquid outlet.

[0046] In an optional embodiment, a protrusion is provided on a side of the locking block close to the connecting rod;

[0047] The inner wall of the locking groove is provided with a limiting groove adapted to the protrusion;

[0048] Wherein, when the limiting block abuts against the side wall of the limiting opening, the protrusion is adapted to be inserted into the limiting groove so as to rotate the limiting dosage scale knob in the opposite direction.

[0049] In an optional embodiment, an air channel is provided on the outer wall of the button along the axial direction, the air channel is adapted to the connecting rod, and an air outlet of the air channel is located between the button and the dosage scale knob;

[0050] When the button moves toward the inner lining, the outer end of the connecting rod is inserted into the airway, so that the air in the airway flows outward to clean the dust between the button and the dosage scale knob.

[0051] In a third aspect, the present disclosure also provides a method for using an injection pen, the method comprising:

[0052] When injection is required, the scale drum rotates outward to a predetermined scale, and the button pushes the dosage scale knob to rotate inward to push the rubber plug in the pen barrel toward the liquid outlet;

[0053] When in a stationary state, the lock tongue retracts and hooks the limit mouth, and the scale knob is used for self-locking.

[0054] The beneficial effect of the present invention is that the anti-drop structure and method for using the injection pen of the present invention utilizes the interaction between the inner lining, the graduated cylinder, and the locking mechanism. When the injection pen is in a stationary state, the locking tongue retracts and hooks onto the limit opening, allowing the graduated knob to self-lock. The locking mechanism prevents the graduated cylinder from rotating outward due to the injection pen being dropped or impacted by external forces, which could result in the waste of liquid medicine in the medicine bottle.

[0055] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description and the drawings.

[0056] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are specifically cited herein and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0058] Figure 1 A schematic diagram of the unfolded state of the anti-fall structure of the injection pen provided by an embodiment of the present disclosure;

[0059] Figure 2 A front view of the locking mechanism and dosage scale knob provided in an embodiment of the present disclosure;

[0060] Figure 3 A schematic diagram of a lock tongue and a limit opening about to self-lock provided by an embodiment of the present disclosure;

[0061] Figure 4 A three-dimensional diagram of a lock tongue provided in an embodiment of the present disclosure;

[0062] Figure 5 A schematic diagram of the locking state of the protrusion and the limiting groove provided in an embodiment of the present disclosure;

[0063] Figure 6 A schematic diagram of a state in which a protrusion according to an embodiment of the present disclosure is disengaged from a limiting groove;

[0064] Figure 7 A three-dimensional diagram of the anti-fall structure of the injection pen provided in an embodiment of the present disclosure.

[0065] In the picture:

[0066] 1. Pen body; 10. Observation window; 11. Rubber stopper;

[0067] 2. Lining; 20. Through hole; 21. Limiting opening; 22. Locking groove; 23. Limiting groove;

[0068] 3. Scaled drum; 31. Drum body; 32. Quantity scale knob;

[0069] 4. Button; 40. Airway;

[0070] 5. Locking mechanism; 50. Lock tongue; 51. Connecting rod; 510. Positioning block; 52. Limiting block; 53. Locking block; 54. Protrusion. DETAILED DESCRIPTION

[0071] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0072] In this document, when it is mentioned that a first component is located on a second component, this may mean that the first component may be directly formed on the second component, or that a third component may be interposed between the first component and the second component. In addition, in the drawings, the thickness of components may be exaggerated or reduced in order to effectively describe technical content.

[0073] Herein, example embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. As used herein, expressions such as "at least one of..." when following a list of elements modify the entire list of elements, rather than modifying individual elements in the list. For example, the expression "at least one of a, b, and c" should be understood to include only a, only b, only c, both a and b, both a and c, both b and c, or all of a, b, and c.

[0074] The terms used herein are only used to describe specific exemplary configurations and are not intended to be limiting. As used herein, the singular articles "a", "an" and "the" may also be intended to include plural forms, unless otherwise clearly indicated herein. The terms "comprise", "include" and "have" are inclusive and therefore specify the presence of features, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components and / or combinations thereof. The method steps, processes and operations described herein should not be interpreted as necessarily requiring them to be performed in the particular order discussed or shown, unless specifically identified as an execution order. Additional or alternative steps may be adopted.

[0075] As used herein, the phrases "in one embodiment," "according to one embodiment," "in some embodiments," and the like generally refer to the fact that the particular feature, structure, or characteristic following the phrase may be included in at least one embodiment of the present disclosure. Thus, a particular feature, structure, or characteristic may be included in more than one embodiment of the present disclosure, such that these phrases do not necessarily refer to the same embodiment. As used herein, the terms "example," "exemplary," and the like are used to "serve as an example, instance, or illustration." Any implementation, aspect, or design described herein as "example" or "exemplary" is not necessarily to be construed as preferred or advantageous over other implementations, aspects, or designs. Instead, the use of the terms "example," "exemplary," and the like is intended to present concepts in a concrete manner.

[0076] Research has found the shortcomings of the existing technology: In the relevant technology, there are already many different types of injection pens to achieve the effect of self-injection by patients. When in use, after rotating the scale cylinder to the specified scale, squeeze the button. The scale cylinder pushes the stopper to move horizontally while rotating to achieve the effect of quantitative injection.

[0077] However, because the graduated cylinder can rotate forward and backward at will, if the pen is dropped or impacted during storage, the graduated cylinder may rotate outward. Patients may then habitually press the button to return the graduated cylinder to zero. Since the graduated cylinder has already rotated outward a few notches, pressing the button directly at this point can cause the stopper to slide horizontally outward, wasting the amount of liquid in the vial.

[0078] Therefore, how to avoid wasting the liquid medicine in the medicine bottle caused by the scale drum rotating outward due to the injection pen falling or being hit by external force is a technical problem that needs to be solved urgently in this field.

[0079] The defects in the above solutions are the results obtained by the inventors after practice and careful research. Therefore, the discovery process of the above problems and the solutions proposed by the present disclosure in this article should be the contributions made by the inventors to the present disclosure during the disclosure process.

[0080] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0081] The following embodiments of the present invention are described in detail with reference to the accompanying drawings. In the absence of conflict, the following embodiments and features therein may be combined with each other.

[0082] like Figures 1 to 7 As shown, some embodiments provide an anti-drop structure for an injection pen, comprising: a graduated cylinder 3, comprising a cylinder body 31 fitted with an inner liner 2, and a dosage scale knob 32 secured to the cylinder body 31; the inner liner 2 disposed within the pen barrel 1; a locking mechanism 5 slidably disposed within the dosage scale knob 32 and comprising a locking tongue 50 adapted to retract toward the inner liner 2; a retaining notch 21 disposed on the inner liner 2 facing the dosage scale knob 32, adapted to mate with the locking tongue 32; when at rest, the locking tongue 50 retracts and engages the retaining notch 21, self-locking the dosage scale knob 32. Through the interaction of the inner liner 2, the graduated cylinder 3, and the locking mechanism 5, when at rest, the locking tongue 50 retracts and engages the retaining notch 21, self-locking the dosage scale knob 32. The locking mechanism 5 prevents the graduated cylinder 3 from rotating outward due to the injection pen being dropped or impacted by external forces, which could result in wasted liquid from the vial.

[0083] Reference Attachment Figure 1 The limiting opening 21 is formed on the side of the inner liner 2 near the scale drum 3, and the side wall of the limiting opening 21 away from the scale drum 3 is arc-shaped. Preferably, there are two limiting openings 21, and the two limiting openings 21 are symmetrically arranged. When the scale drum 3 rotates to zero, the locking tongue 50 abuts against the side wall of the limiting opening 21, preventing the scale drum 3 from further rotation. The locking tongue 50 cooperates with the locking groove 22 to limit the outward rotation of the scale drum 3.

[0084] Reference Attachment Figure 2 The locking mechanism 5 comprises: a connecting rod 51, which passes through the dosage scale knob 32 and abuts against the button 4 at its outer end; a positioning block 510 is provided on the outer wall of the connecting rod 51, and a spring is provided between the positioning block 510 and the inner wall of the dosage scale knob 32, and the spring is adapted to push the connecting rod 51 to move away from the lining 2. The locking tongue 50 is provided at the inner end of the connecting rod 51; the locking tongue 50 comprises: a limiting block 52, which is provided at the inner end of the connecting rod 51; when the rotating drum body (31) rotates to zero scale, the limiting block 52 is adapted to be inserted into the limiting opening 21; a locking block 53, which is provided on the side wall of the limiting block 52, and the locking block 53 is adapted to be matched with the locking groove 22; wherein, the button 4 pushes the dosage scale knob 32 to slide inward, and when the scale of the rotating drum body (31) is zero, the limiting block 52 is adapted to abut against the side wall of the limiting opening 21. The inner wall of the limit opening 21 is provided with a locking groove 22, and the locking groove 22 faces the limit block 52; when the limit block 52 abuts against the inner wall of the limit opening 21, the locking block 53 is adapted to be inserted into the locking groove 22. The length of the locking block 53 is less than the slot length of the locking groove 22; in a stationary state, the locking block 53 is inserted into the locking groove 22, so that the locking tongue (50) is self-locking. When injection is required, the button 4 moves toward the pen barrel 1, and the connecting rod 51 pushes the locking block 53 to slide into the locking groove 22; until the locking block 53 is separated from the locking groove 22; the dosage scale knob 32 slides outward until the drum body 31 rotates to a predetermined scale; the button 4 moves inward, and the scale drum 3 rotates inward to push the liquid in the medicine bottle to flow outward, so as to achieve the effect of quantitative injection.

[0085] Reference Attachment Figure 4The locking block 53 is provided with a protrusion 54 on the side closest to the connecting rod 51. The inner wall of the locking groove 22 is provided with a stop groove 23 that matches the protrusion 54. When the stop block 52 abuts the side wall of the stop opening 21, the protrusion 54 is adapted to be inserted into the stop groove 23. At this time, the scale drum 3 cannot rotate outward relative to the liner 2. To inject again, the button 4 is pressed, which pushes the connecting rod 51, moving it toward the liner 2 until the protrusion 54 disengages from the stop groove 23. The scale drum 3 is then rotated in the opposite direction, and is adapted to rotate outward relative to the liner 2.

[0086] Reference Attachment Figure 5 An air passage 40 is axially formed on the outer wall of the button 4, and the air passage 40 is adapted to the connecting rod 51. The air outlet of the air passage 40 is located between the button 4 and the scale cylinder 3. When the button 4 is pushed toward the pen barrel 1, the outer end of the connecting rod 51 is inserted into the air passage 40, so that the air in the air passage 40 flows outward to clean the dust between the button 4 and the dosage scale knob 32.

[0087] Reference Attachment Figure 7Some embodiments provide an injection pen, comprising: a pen barrel 1 having an observation window 10 defined on its outer wall; a medicine chamber disposed on a side of the pen barrel 1 away from a button 4, the medicine chamber being suitable for placing a medicine bottle; a transmission connecting rod structure adapted to a rubber stopper of the medicine bottle being disposed within the pen barrel 1; when the button 4 is pressed to push a graduated rotating drum 3 to spirally move into the pen barrel 1, the transmission connecting rod structure is adapted to push the rubber stopper in the medicine bottle to slide outward, thereby pushing the liquid medicine in the medicine bottle to flow outward, thereby achieving a quantitative injection effect. The liner 2 is arranged in the pen barrel 1 and has a through hole 20 corresponding to the observation window 10; the scale drum 3 is arranged inside the liner 2, and the scale drum 3 includes: a drum body 31, which is threadably adapted to the liner 2, and a dosage scale knob 32 sleeved on the drum body 31; a button 4, which is slidably arranged at the end of the dosage scale knob 32; a locking mechanism 5, which is slidably arranged inside the dosage scale knob 32 and is linked to the button 4; wherein, the scale drum 3 rotates outward to a predetermined scale, and the button 4 pushes the scale drum 3 to rotate to push the rubber plug in the pen barrel 1 toward the liquid outlet; after the lock tongue 50 is inserted into the limiting opening 21 of the liner 2, it limits the scale drum 3 from rotating outward. Through the interaction of the liner 2, graduated cylinder 3, and locking mechanism 5, when the graduated cylinder 3 rotates to zero, indicating the end of injection, the locking mechanism 5 engages the stop opening 21, and the protrusion 54 engages the stop groove 23, preventing the graduated cylinder 3 from rotating in the opposite direction. The locking mechanism 5 prevents the graduated cylinder 3 from rotating outward due to the pen being dropped or impacted by external forces, which could waste the liquid in the vial. To use the pen again, press the button 4 to disengage the protrusion 54 from the stop groove 23, and rotate the graduated cylinder 3 outward in the opposite direction to achieve another dosed injection.

[0088] Some embodiments provide a method for using an injection pen, which includes: rotating the scale drum 3 outward to a predetermined scale, pressing the button 4, and the button 4 drives the scale drum 3 to rotate to push the rubber plug in the pen body 1 toward the liquid outlet; after the locking mechanism 5 is inserted into the limiting opening 21 of the liner 2, the locking mechanism 5 is suitable for limiting the scale drum 3 from sliding outward in the opposite direction.

[0089] In summary, when the pen is at rest, the locking tongue 50 retracts and hooks onto the stopper 21, locking the dosage scale knob 32. To use the injection pen, the button 4 pushes the connecting rod 51, disengaging the locking block 53 from the locking groove 22. The dosage scale knob 3 is then rotated outward to a predetermined scale, and the button 4 pushes the dosage scale knob 32 inward, pushing the rubber stopper 11 inside the pen barrel 1 toward the liquid outlet.

[0090] In the description of the embodiments of the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0091] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, terms such as "first", "second" and other numerical terms do not imply an order or sequence when used herein unless expressly indicated above. Therefore, without departing from the teachings of the example embodiments, the first element, component, region, layer or section discussed above may be referred to as a second element, component, region, layer or section.

[0092] With the above-described preferred embodiments of the present invention as a guide, and with reference to the above description, relevant personnel are fully capable of making various changes and modifications without departing from the technical scope of this invention. The technical scope of this invention is not limited to the contents of the specification and must be determined according to the scope of the claims.

Claims

1. An anti-fall structure for an injection pen, characterized in that: include: The graduated rotary drum (3) comprises a rotary drum body (31) sleeved with an inner lining (2), and a dosage scale knob (32) sleeved on the rotary drum body (31); A locking mechanism (5) is slidably arranged inside the dosage scale knob (32) and includes a locking tongue (50) adapted to retract toward the side of the lining (2); The inner lining (2) is provided with a limiting opening (21) adapted to the locking tongue (50) on the side facing the dosage scale knob (32); In the static state, the lock tongue (50) retracts and hooks the limit opening (21), and the scale knob (32) is used for self-locking; The locking mechanism (5) comprises: a connecting rod (51) which passes through the dosage scale knob (32) and whose outer end abuts against a button (4); the button (4) is slidably arranged on the outer end of the dosage scale knob (32); The locking tongue (50) is arranged at the inner end portion of the connecting rod (51); The button (4) pushes the dosage scale knob (32) to slide inward, and the locking tongue (50) is adapted to abut against the side wall of the limiting opening (21); The inner wall of the limiting opening (21) is provided with a locking groove (22); The locking tongue (50) comprises: a limiting block (52) arranged at the inner end of the connecting rod (51); A locking block (53) is provided on a side wall of the limiting block (52), and the locking block (53) is adapted to the locking groove (22); When the limiting block (52) abuts against the inner wall of the limiting opening (21), the locking block (53) is adapted to be inserted into the locking groove (22).

2. The anti-fall structure of the injection pen according to claim 1, characterized in that: The length of the locking block (53) is smaller than the slot length of the locking slot (22); In the static state, the locking block (53) is inserted into the locking groove (22) so that the locking tongue (50) is self-locking.

3. The anti-fall structure of the injection pen according to claim 2, characterized in that: A protrusion (54) is provided on one side of the locking block (53) close to the connecting rod (51); The inner wall of the locking groove (22) is provided with a limiting groove (23) adapted to the protrusion (54); When the limiting block (52) abuts against the side wall of the limiting opening (21), the protrusion (54) is adapted to be inserted into the limiting groove (23) so as to rotate the limiting dosage scale knob (32) in the opposite direction.

4. The anti-fall structure of the injection pen according to claim 1, characterized in that: An air passage (40) is provided on the outer wall of the button (4) along the axial direction. The air passage (40) is adapted to the connecting rod (51). The air outlet of the air passage (40) is located between the button (4) and the dosage scale knob (32). When the button (4) pushes the connecting rod (51) to move toward the lining (2), the outer end of the connecting rod (51) is inserted into the air passage (40) so that the air in the air passage (40) flows outward to clean the dust between the button (4) and the dosage scale knob (32).

5. An injection pen, characterized in that: include: The pen body tube (1) has an observation window (10) formed on its outer wall; An inner lining (2) is arranged in the pen body (1) and has a through hole (20) corresponding to the observation window (10); A graduated rotary drum (3) rotatably arranged inside the inner liner (2); The graduated rotary drum (3) comprises: a rotary drum body (31) threadably adapted to the inner liner (2); and a dosage scale knob (32) sleeved on the drum body (31); A button (4) is slidably arranged at the end of the dosage scale knob (32); A locking mechanism (5) is slidably disposed inside the dosage scale knob (32) and is linked to the button (4); After the rotating drum body (31) rotates outward to a predetermined scale, the button (4) pushes the scale rotating drum (3) to rotate inward, thereby pushing the rubber plug (11) in the pen barrel (1) to move toward the liquid outlet; In a stationary state, the locking tongue (50) of the locking mechanism (5) is inserted into a limiting opening (21) provided on the side wall of the lining (2) so as to self-lock using the scale knob (32); The locking mechanism (5) comprises: a connecting rod (51) which passes through the dosage scale knob (32) and has an outer end in contact with the button (4); A locking tongue (50) is provided at the inner end of the connecting rod (51) and is adapted to be inserted into the limiting opening (21); The locking tongue (50) comprises: a limiting block (52) arranged at the inner end of the connecting rod (51); A locking block (53) is provided on a side wall of the limiting block (52), and the locking block (53) is suitable for being inserted into a locking groove (22) on an inner wall of the limiting opening (21); The button (4) pushes the dosage scale knob (32) to slide inward until the limit block (52) abuts against the inner wall of the limit opening (21), and the locking block (53) is suitable for being inserted into the locking groove (22).

6. The injection pen according to claim 5, wherein: The length of the locking block (53) is smaller than the slot length of the locking slot (22); Wherein, in a stationary state, the locking block (53) is inserted into the locking groove (22) so that the locking tongue (50) is self-locking; When injection is required, the button (4) pushes the connecting rod (51) to disengage the locking block (53) from the locking groove (22); The dosage scale knob (32) is rotated outward to a predetermined scale, and the button (4) pushes the dosage scale knob (32) to rotate inward, thereby pushing the rubber plug (11) in the pen body barrel (1) to move toward the liquid outlet.

7. The injection pen according to claim 6, wherein: A protrusion (54) is provided on one side of the locking block (53) close to the connecting rod (51); The inner wall of the locking groove (22) is provided with a limiting groove (23) adapted to the protrusion (54); When the limiting block (52) abuts against the side wall of the limiting opening (21), the protrusion (54) is adapted to be inserted into the limiting groove (23) so as to rotate the limiting dosage scale knob (32) in the opposite direction.

8. The injection pen according to claim 7, wherein: An air passage (40) is provided on the outer wall of the button (4) along the axial direction. The air passage (40) is adapted to the connecting rod (51). The air outlet of the air passage (40) is located between the button (4) and the dosage scale knob (32). When the button (4) moves toward the lining (2), the outer end of the connecting rod (51) is inserted into the air passage (40), so that the air in the air passage (40) flows outward to clean the dust between the button (4) and the dosage scale knob (32).

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