Anti-falling structure of injection pen and use method of anti-falling structure

Abstract

The invention belongs to the technical field of medicine, and particularly relates to an injection pen anti-falling structure and a using method thereof. The invention provides an anti-drop structure for an injection pen, comprising: a scale drum comprising a drum body sleeved with a lining and a dosage scale knob sleeved on the drum body; the locking mechanism is arranged in the dosage scale knob and comprises a spring bolt which faces the lining side and is suitable for retreating; a limiting opening matched with the spring bolt is formed in the side, facing the dosage scale rotary knob, of the lining. And in a static state, the spring bolt retreats to hook the limiting opening, so that the scale knob is used for self-locking. Through mutual cooperation of the lining, the scale rotating cylinder and the locking mechanism, when the scale rotating cylinder rotates to zero scale, the locking mechanism can lock the scale rotating cylinder to prevent the scale rotating cylinder from rotating outwards, and waste of medicine in the pen body cylinder is avoided.

Description

Technical Field

[0001] The invention belongs to the field of medical technology, and specifically relates to a syringe, and in particular to an anti-fall structure of an injection pen and a use method thereof. Background Art

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

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

[0004] However, since the graduated cylinder can rotate forward and backward at will, when the injection pen is dropped or hit by external force during storage, the graduated cylinder will rotate outward. At this time, the patient will habitually squeeze the button to restore the graduated cylinder to zero scale. Since the graduated cylinder has rotated outward by some scales, directly squeezing the button at this time will cause the rubber stopper to slide outward horizontally, wasting the measured amount of the liquid medicine in the medicine bottle.

[0005] Therefore, how to avoid wasting the liquid medicine in the medicine bottle due to the outward rotation of the graduated rotating drum caused by 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 disclosed embodiments 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-fall structure for an injection pen, comprising: The graduated rotary drum comprises a rotary drum body sleeved with an inner liner, and a dosage graduated knob sleeved on the rotary drum body; A locking mechanism is slidably disposed inside the dosage scale knob and includes a locking tongue facing the lining side and adapted to retract; The inner lining is provided with a limit opening adapted to the lock tongue on the side facing the dosage scale knob; When in a stationary state, the lock tongue retracts and hooks the limit opening, so that the measuring scale knob can be used for self-locking.

[0009] 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 at the outer end of the dosage scale knob; The locking tongue is arranged at the inner end of the connecting rod; 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.

[0010] In an optional embodiment, a locking groove is provided on the inner wall of the limit opening; The locking tongue comprises: a limiting block, which is arranged at the inner end of the connecting rod; A locking block, which is arranged on the side wall of the limiting block, and the locking block is adapted to the locking groove; 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.

[0011] In an optional embodiment, the length of the locking block is smaller than the slot length of the locking slot; Wherein, in the static state, the locking block is inserted into the locking groove so that the locking tongue is self-locking.

[0012] In an optional embodiment, a protrusion is provided on one side of the locking block close to the connecting rod; The inner wall of the locking groove is provided with a limiting groove adapted to the protrusion; Wherein, when the limiting block abuts against the side wall of the limiting opening, the protrusion is suitable for being inserted into the limiting groove so that the limiting dosage scale knob rotates in the opposite direction.

[0013] In an optional embodiment, an air passage is provided on the outer wall of the button along the axial direction, the air passage is adapted to the connecting rod, and an air outlet of the air passage is located between the button and the dosage scale knob; 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.

[0014] In a second aspect, the present disclosure also provides an injection pen, including: The pen body tube has an observation window on its outer wall; The inner lining is arranged in the pen body tube and has a through hole corresponding to the observation window; a graduated rotating drum, which is rotatably arranged inside the liner; The graduated rotary drum comprises: a rotary drum body, which is adapted to the inner liner thread; and a dosage scale knob sleeved on the drum body; A button, which is slidably arranged at the end of the dosage scale knob; A locking mechanism is slidably disposed inside the dosage scale knob and is linked to the button; After the rotating drum body rotates outward to a predetermined scale, the button pushes the graduated rotating drum to rotate inward, so as to push the rubber plug in the pen body to move toward the liquid outlet; In a static state, the locking tongue of the locking mechanism is inserted into a limiting opening provided on the side wall of the liner so as to be self-locked using the measuring scale knob.

[0015] 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; A locking tongue, which is arranged at the inner end of the connecting rod and is suitable for being inserted into the limiting opening; The locking tongue comprises: a limiting block, which is arranged at the inner end of the connecting rod; A locking block, which is arranged on the side wall of the limiting block, and the locking block is suitable for being inserted into the locking groove of the inner wall of the limiting opening; Among them, 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.

[0016] In an optional embodiment, the length of the locking block is smaller than the slot length of the locking slot; Wherein, in the static state, the locking block is inserted into the locking groove so that the locking tongue is self-locking; When injection is required, the button pushes the connecting rod to disengage the locking block from the locking groove; The dosage scale knob is rotated outward to a predetermined scale, and the button pushes the dosage scale knob to rotate inward to push the rubber plug in the pen body barrel to move toward the liquid outlet.

[0017] In an optional embodiment, a protrusion is provided on one side of the locking block close to the connecting rod; The inner wall of the locking groove is provided with a limiting groove adapted to the protrusion; Wherein, when the limiting block abuts against the side wall of the limiting opening, the protrusion is suitable for being inserted into the limiting groove so that the limiting dosage scale knob rotates in the opposite direction.

[0018] In an optional embodiment, an air passage is provided on the outer wall of the button along the axial direction, the air passage is adapted to the connecting rod, and an air outlet of the air passage is located between the button and the dosage scale knob; 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.

[0019] In a third aspect, the present disclosure also provides a method for using an injection pen, the method comprising: When injection is required, after the graduated rotating cylinder is rotated outward to a predetermined scale, the button pushes the dosage graduated knob to rotate inward to push the rubber plug in the pen barrel toward the liquid outlet; When in a stationary state, the lock tongue retracts and hooks the limit opening, so that the measuring scale knob can be used for self-locking.

[0020] The beneficial effect of the present invention is that the anti-fall structure of the injection pen and the use method thereof of the present invention cooperate with each other through the inner lining, the scale rotating cylinder and the locking mechanism. When in a stationary state, the locking tongue retracts and hooks the limit opening, so that the scale knob is self-locked. The locking mechanism avoids the situation where the scale rotating cylinder rotates outward due to the injection pen falling or being hit by external force, causing the liquid medicine in the medicine bottle to be wasted.

[0021] Other features and advantages of the present invention will be described in the following description, and partly 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.

[0022] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, this article specifically cites preferred embodiments and provides detailed descriptions as follows in conjunction with the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 A schematic diagram of an unfolded state of the anti-fall structure of the injection pen provided in an embodiment of the present disclosure; Figure 2 A front view of the locking mechanism and the dosage scale knob provided in the embodiment of the present disclosure; Figure 3 A schematic diagram of a state where the lock tongue and the limit opening are about to be self-locked provided in an embodiment of the present disclosure; Figure 4 A three-dimensional diagram of a locking tongue provided in an embodiment of the present disclosure; Figure 5 A schematic diagram of the locking state of the protrusion and the limiting groove provided in the embodiment of the present disclosure; 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; Figure 7 A three-dimensional diagram of the anti-fall structure of the injection pen provided in an embodiment of the present disclosure.

[0025] In the figure: 1. Pen body; 10. Observation window; 11. Rubber plug; 2. Lining; 20. Through hole; 21. Limiting opening; 22. Locking groove; 23. Limiting groove; 3. Scaled rotating drum; 31. Rotating drum body; 32. Quantity scale knob; 4. Button; 40. Airway; 5. Locking mechanism; 50. Lock tongue; 51. Connecting rod; 510. Positioning block; 52. Limiting block; 53. Locking block; 54. Protrusion. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] In this article, when it is mentioned that the first component is located on the second component, this may mean that the first component may be directly formed on the second component, or the third component may be interposed between the first component and the second component. In addition, in the drawings, in order to effectively describe the technical content, the thickness of the components may be exaggerated or reduced.

[0028] 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..." modify the entire list of elements when following a 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.

[0029] The terms used herein are only used to describe specific exemplary configurations and are not intended to be limited. As used herein, the singular articles "one", "an" and "the" may also be intended to include plural forms, unless it is clearly indicated above that this is not the case. 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 specific order discussed or shown, unless specifically identified as an execution order. Additional or alternative steps may be adopted.

[0030] 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. Therefore, a particular feature, structure, or characteristic may be included in more than one embodiment of the present disclosure, so 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 superior to other implementations, aspects, or designs. On the contrary, the use of the terms "example," "exemplary," and the like is intended to present concepts in a concrete manner.

[0031] 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, and the scale cylinder pushes the stopper to move horizontally while rotating to achieve the effect of quantitative injection.

[0032] However, since the graduated cylinder can rotate forward and backward at will, when the injection pen is dropped or hit by external force during storage, the graduated cylinder will rotate outward. At this time, the patient will habitually squeeze the button to restore the graduated cylinder to zero scale. Since the graduated cylinder has rotated outward by some scales, directly squeezing the button at this time will cause the rubber stopper to slide outward horizontally, wasting the measured amount of the liquid medicine in the medicine bottle.

[0033] Therefore, how to avoid wasting the liquid medicine in the medicine bottle due to the outward rotation of the graduated rotating drum caused by the injection pen falling or being hit by external force is a technical problem that needs to be solved urgently in this field.

[0034] The defects existing in the above solutions are the results obtained by the inventor after practice and careful research. Therefore, the discovery process of the above problems and the solutions proposed by the present invention in this article for the above problems should be the contributions made by the inventor to the present invention during the disclosure process.

[0035] 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, further definition and explanation thereof is not required in subsequent drawings.

[0036] Some embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0037] like Figures 1 to 7As shown, some embodiments provide an anti-fall structure for an injection pen, comprising: a graduated rotating drum 3, comprising a rotating drum body 31 sleeved with an inner liner 2, and a dosage scale knob 32 sleeved on the rotating drum body 31; the inner liner 2 is arranged in the pen body 1; a locking mechanism 5, which is slidably arranged inside the dosage scale knob 32, and comprises a locking tongue 50 suitable for retreating toward the inner liner 2; the inner liner 2 is provided with a limiting opening 21 adapted to the locking tongue 32 toward the dosage scale knob 32; in a stationary state, the locking tongue 50 retreats and hooks the limiting opening 21, so as to self-lock the dosage scale knob 32. Through the mutual cooperation of the inner liner 2, the graduated rotating drum 3 and the locking mechanism 5, in a stationary state, the locking tongue 50 retreats and hooks the limiting opening 21, so as to self-lock the dosage scale knob 32. The locking mechanism 5 avoids the situation where the medicine in the medicine bottle is wasted due to the graduation rotating drum 3 rotating outwards due to the injection pen falling or being hit by external force.

[0038] Reference Figure 1 The limiting opening 21 is provided on a side of the inner liner 2 close to the scale drum 3, and a side wall of the limiting opening 21 away from the scale drum 3 is in an arc shape. Preferably, there are two limiting openings 21, and the two limiting openings 21 are symmetrically arranged; when the scale drum 3 rotates to zero scale, the locking tongue 50 abuts against the side wall of the limiting opening 21, and the limiting opening 21 is suitable for preventing the scale drum 3 from continuing to rotate. The cooperation between the locking tongue 50 and the locking groove 22 limits the outward rotation of the scale drum 3.

[0039] Reference Figure 2The locking mechanism 5 comprises: a connecting rod 51, which passes through the dosage scale knob 32, and the outer end of which abuts against the button 4; a positioning block 510 is arranged on the outer wall of the connecting rod 51, and a spring is arranged between the positioning block 510 and the inner wall of the dosage scale knob 32, and the spring is suitable for pushing the connecting rod 51 to move away from the liner 2. The locking tongue 50 is arranged at the inner end of the connecting rod 51; the locking tongue 50 comprises: a limit block 52, which is arranged at the inner end of the connecting rod 51; when the rotating drum body (31) rotates to zero scale, the limit block 52 is suitable for inserting into the limit opening 21; a locking block 53, which is arranged on the side wall of the limit block 52, and the locking block 53 is adapted to 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 limit block 52 is suitable for abutting against the side wall of the limit 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 separates 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 medicine in the medicine bottle to flow outward, so as to achieve the effect of quantitative injection.

[0040] Reference Figure 4 The locking block 53 is provided with a protrusion 54 on one side 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; wherein, 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, and at this time, the scale rotating cylinder 3 cannot be reversely rotated outward relative to the liner 2. When another injection is required, the button 4 is pressed, and the button 4 pushes the connecting rod 51 to move the connecting rod 51 toward the direction of the liner 2 until the protrusion 54 is disengaged from the limiting groove 23, and the scale rotating cylinder 3 is reversely rotated, and the scale rotating cylinder 3 is adapted to be reversely rotated outward relative to the liner 2.

[0041] Reference Figure 5 An air passage 40 is axially provided on the outer wall of the button 4, and the air passage 40 is matched with the connecting rod 51, and the air outlet of the air passage 40 is located between the button 4 and the scale rotating cylinder 3; wherein, when the button 4 is pushed to move toward the pen body 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.

[0042] Reference Figure 7 Some embodiments provide an injection pen, including: a pen barrel 1, an outer wall of which is provided with an observation window 10; a medicine chamber is provided on a side of the pen barrel 1 away from a button 4, and the medicine chamber is suitable for placing a medicine bottle; a transmission connecting rod structure adapted to a rubber stopper of the medicine bottle is provided in the pen barrel 1, and when the button 4 is pressed to push the scale rotating cylinder 3 to move spirally into the pen barrel 1, the transmission connecting rod structure is suitable for pushing the rubber stopper in the medicine bottle to slide outward, so as to push the liquid medicine in the medicine bottle to flow outward, so as to achieve the effect of quantitative injection. 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 with 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 to move toward the liquid outlet; after the locking tongue 50 is inserted into the limiting opening 21 of the liner 2, the limiting scale drum 3 rotates outward. Through the cooperation between the liner 2, the graduated cylinder 3 and the locking mechanism 5, when the graduated cylinder 3 rotates to the zero scale, that is, the injection is finished, the locking mechanism 5 is inserted into the limit opening 21, and the protrusion 54 is inserted into the limit groove 23 to prevent the graduated cylinder 3 from rotating in the opposite direction. The locking mechanism 5 avoids the situation where the graduated cylinder 3 rotates outward due to the injection pen falling or being hit by external force, which causes the waste of the liquid medicine in the medicine bottle. When the injection pen is used again, the button 4 is pressed to disengage the protrusion 54 from the limit groove 23, and the graduated cylinder 3 is rotated outward in the opposite direction to achieve quantitative injection again.

[0043] Some embodiments provide a method for using an injection pen, the method comprising: rotating the scale drum 3 outward to a predetermined scale, pressing the button 4, the button 4 pushing the scale drum 3 to rotate, so as to push the rubber plug in the pen body 1 to move toward the liquid outlet; after the locking mechanism 5 is inserted into the limiting opening 21 of the lining 2, the locking mechanism 5 is suitable for limiting the scale drum 3 to slide outward in the opposite direction.

[0044] In summary, in the static state, the locking tongue 50 retracts and hooks the limit opening 21, so as to self-lock the use scale knob 32. When the injection pen needs to be used, the button 4 pushes the connecting rod 51 to disengage the locking block 53 from the locking groove 22; the scale knob 3) is rotated outward to a predetermined scale, and the button 4 pushes the scale knob 32 to rotate inward to push the rubber plug 11 in the pen body 1 to move toward the liquid outlet.

[0045] In the description of the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0046] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. is based on the orientation or positional relationship shown in the drawings, which is 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 a limitation of the present invention. In addition, terms such as "first", "second" and other numerical terms do not imply an order or sequence when used in this document unless explicitly 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.

[0047] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope 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 graduated knob (32) sleeved on the rotary drum body (31); A locking mechanism (5) which is slidably disposed inside the dosage scale knob (32) and comprises a locking tongue (50) which is adapted to retract toward the side of the liner (2); The inner lining (2) is provided with a limiting opening (21) adapted to the locking tongue (32) on the side facing the dosage scale knob (32); In the static state, the locking tongue (50) retracts and hooks the limit opening (21) to self-lock using the measuring scale knob (32).

2. The anti-fall structure of the injection pen according to claim 1, characterized in that: 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 of the connecting rod (51); The button (4) pushes the dosage scale knob (32) to slide inward, and the locking tongue (50) is suitable for abutting against the side wall of the limiting opening (21).

3. The anti-fall structure of the injection pen according to claim 2, characterized in that: 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) disposed on a side wall of the limiting block (52), the locking block (53) being adapted to fit 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).

4. The anti-fall structure of the injection pen according to claim 3, characterized in that: 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.

5. The anti-fall structure of the injection pen according to claim 4, 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 fit 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.

6. The anti-fall structure of the injection pen according to claim 2, 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), and an 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 in the direction of the liner (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 outwards to clean the dust between the button (4) and the dosage scale knob (32).

7. 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) formed at a position corresponding to the observation window (10); A graduated rotating drum (3) rotatably arranged inside the inner liner (2); The graduated rotary drum (3) comprises: a rotary drum body (31) which is threadably adapted to the inner liner (2); and a dosage scale knob (32) sleeved on the drum body (31); A button (4) slidably disposed at the end of the dosage scale knob (32); A locking mechanism (5) which 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 graduated 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 liner (2) so as to be self-locked using the measuring scale knob (32).

8. The injection pen according to claim 7, characterized in that: The locking mechanism (5) comprises: a connecting rod (51) which passes through the dosage scale knob (32) and whose outer end abuts against the button (4); A locking tongue (50) disposed at the inner end of the connecting rod (51) and 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) disposed on a side wall of the limiting block (52), the locking block (53) being 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).

9. The injection pen according to claim 8, characterized in that: 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, so as to push the rubber plug (11) in the pen body tube (1) to move toward the liquid outlet.

10. The injection pen according to claim 9, 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 fit 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.

11. The injection pen according to claim 10, 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), and an 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 outwards to clean the dust between the button (4) and the dosage scale knob (32).

12. A method for using an injection pen, characterized in that: Using the injection pen according to any one of claims 7 to 11, the method of using comprises: When injection is required, after the graduated rotating cylinder (3) is rotated outward to a predetermined scale, the button (4) pushes the dosage graduated knob (32) to rotate inward, thereby pushing the rubber plug (11) in the pen body (1) to move toward the liquid outlet; In the static state, the locking tongue (50) retracts and hooks the limit opening (21) to self-lock using the measuring scale knob (32).

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