Medical injection pen

Abstract

The invention provides a medical injection pen. The medical injection pen comprises a pen container, a pressing assembly, a transmission assembly and an injection assembly. The interior of the pen container is divided into an installation channel and a liquid injection channel. The pressing assembly comprises a digital barrel, a sliding barrel and a pressing head, the screwing part is rotationally arranged at the upper end of the mounting channel, the pressing head is arranged on the screwing part, and the sliding barrel is arranged in the digital barrel in a sliding mode and is in transmission connection with the pressing head; the transmission assembly comprises a push rod and a transmission ring, and the transmission ring is arranged in the sliding cylinder in a sliding mode. The inner wall of the transmission ring is in threaded fit with the push rod, and a limiting protrusion is arranged at the upper end of the push rod and can be matched with the upper end face of the transmission ring. The injection assembly has a cartridge bottle. According to the medical injection pen, after injection is completed, the limiting protrusion at the upper end of the push rod abuts against the transmission rod up and down, so that a patient cannot screw the digital tube outwards, and the patient is reminded to replace the injection pen.

Description

Technical Field

[0001] The invention belongs to the technical field of medical devices, and in particular relates to a medical injection pen. Background Art

[0002] When treating some diseases for patients, syringes are generally used to inject drugs directly into human tissues to achieve effective treatment results. An injection pen is a type of syringe that can automatically inject liquid drugs pre-filled into the syringe barrel into the patient's body. It can meet the user's need for self-administration and reduce the number of times patients go back and forth for treatment.

[0003] After using the liquid medicine in a single injection pen, the injection pen needs to be discarded to avoid cross infection caused by repeated use. Since the inside of the injection pen is not visible, it is difficult for the patient to judge whether the liquid medicine has been used up, which affects the patient's judgment and may even cause an empty injection pen to be inserted into the human body, causing injection failure. The patient cannot replace or purchase a new injection pen in time, which affects the patient's treatment effect and brings inconvenience to the patient. Summary of the invention

[0004] The embodiment of the present invention provides a medical injection pen, which aims to solve the problem in the prior art that the injection pen cannot promptly remind the patient to replace the medicine after the medicine liquid is used up, thus affecting the patient's treatment.

[0005] To achieve the above object, the technical solution adopted by the present invention is: Provided is a medical injection pen, comprising: The pen barrel has a limiting portion inside, the limiting portion divides the inside of the pen barrel into an installation channel and a liquid injection channel distributed in the up-down direction, and a through hole is provided in the middle of the limiting portion; The pressing assembly comprises a digital tube, a sliding tube and a pressing head. The upper end of the digital tube forms a screwing part, the screwing part is rotatably arranged at the upper end of the installation channel, the outer periphery of the digital tube is threadedly matched with the side wall of the installation channel, the pressing head is slidably arranged on the screwing part, the sliding tube is only slidably arranged inside the digital tube along the axis of the installation channel, and the top end of the sliding tube is transmission-connected with the pressing head; A transmission assembly, comprising a push rod and a transmission ring, wherein the transmission ring is slidably arranged inside the sliding cylinder along the axis of the installation channel, and a circumferential limiter is arranged on the inner wall of the sliding cylinder, and the circumferential limiter is used to limit the rotation of the transmission ring relative to the sliding cylinder in the circumferential direction; the inner wall of the transmission ring is threadedly matched with the push rod, and the push rod passes through the limiter and extends into the injection channel, and a limit protrusion is arranged on the upper end of the push rod, and the limit protrusion can be matched with the upper end surface of the transmission ring to limit the axial displacement of the push rod when the liquid medicine is exhausted; and The injection assembly comprises a cartridge bottle which is clamped at the opening of the injection channel, and the piston of the cartridge bottle is in contact with the push rod.

[0006] In a possible implementation, the pressing assembly also includes a bushing, which is fixed at the opening of the installation channel, the inner wall of the bushing is provided with an internal thread, the outer periphery of the digital tube is provided with a thread groove corresponding to the internal thread, and the internal thread is threadably matched with the thread groove.

[0007] In a possible implementation, the transmission assembly further includes: A transmission member, one end of which is connected to the upper end of the sliding cylinder, and the other end of which is slidably connected to the pressing head; An elastic member, two ends of which are respectively connected to the pressing head and the transmission member; and A push plate is arranged at one end of the push rod away from the pressing head, and the push plate abuts against the piston of the cartridge bottle.

[0008] In a possible implementation, a guide sleeve is provided at one end of the transmission member facing the pressing head, the pressing head is arranged on a guide column corresponding to the guide sleeve, the guide column is plugged into the guide sleeve, and the elastic member is simultaneously sleeved on the outer periphery of the guide column and the guide sleeve.

[0009] In a possible implementation, an anti-disengagement hook is provided on the outer periphery of one end of the pressing head facing the digital tube, and the digital tube is provided with an anti-disengagement groove corresponding to the anti-disengagement hook, and the anti-disengagement hook is engaged with the anti-disengagement groove to limit the displacement of the pressing head on the axis of the installation channel.

[0010] In a possible implementation, the circumferential limit member includes a guide protrusion provided on the outer circumference of the transmission ring and a guide groove provided on the inner wall of the sliding cylinder, the guide groove extends along the axis of the sliding cylinder, and the guide protrusion and the guide groove slide up and down in cooperation.

[0011] In a possible implementation, a reading port is provided on the outer circumference of the pen holder, the reading port is communicated with the installation channel, and a scale is provided on the outer wall of the digital tube.

[0012] In a possible implementation, the medical injection pen further includes a sound component, and the sound component includes: A sounding member is fixedly arranged in the injection channel, a sounding groove is provided at the upper end of the sounding member, a toothed ring is provided on the groove wall of the sounding groove, and the sounding groove and the limiting portion are enclosed to form a fixed space; a striking ring rotatably disposed in the fixed space, the inner wall of the striking ring being in threaded engagement with the push rod, a striking arm being disposed on the outer periphery of the striking ring, the striking arm being in contact with the gear ring; and The transmission tooth is arranged between the striking ring and the sliding cylinder, and the upper and lower ends of the transmission tooth can be respectively engaged with the striking ring and the sliding cylinder.

[0013] In a possible implementation, the transmission assembly further includes a pen cap, which is disposed on the outer periphery of the injection assembly and is connected to the bottom opening of the injection channel.

[0014] In a possible implementation, the injection assembly further includes a refill rack, the cartridge bottle is clamped inside the refill rack, and the top of the refill rack is clamped on the inner wall of the injection channel.

[0015] The medical injection pen provided by the present invention provides a new transmission mode compared with the prior art. The digital tube limits the sliding tube circumferentially through a circumferential limiting portion. The sliding tube is connected to the push rod through a transmission ring. The top of the sliding tube is also connected to the pressing head through transmission. When the patient adjusts the injection dose, the digital tube is rotated. At this time, the transmission ring rotates with the sliding tube, and the transmission ring rises relative to the push rod. When injecting, the patient pushes the pressing head downward, and the pressing head drives the sliding tube to descend. The descending of the sliding tube drives the transmission ring to descend. Since the inner wall of the transmission ring is screwed to the push rod, the descending of the transmission ring drives the push rod to descend, which drives the liquid in the cartridge bottle to change, thereby realizing the injection. When the injection is completed, the limiting protrusion on the upper end of the push rod abuts against the transmission rod up and down, so that the patient cannot twist the digital tube outward, thereby realizing the reminder for the patient to replace the injection pen. The whole process is simple. With each injection of the liquid medicine, the transmission ring rises relative to the push rod, which can remind the patient in time. The whole process is mechanical transmission, which is simple to operate and has high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0017] Figure 1 A schematic diagram of the main structure of a medical injection pen provided by an embodiment of the present invention; Figure 2 for Figure 1 sectional view of; Figure 3 for Figure 2 A schematic diagram of the structure of the sound component used in the invention; Figure 4 for Figure 1 The structural diagram of the digital tube used in the embodiment; Figure 5 for Figure 2A schematic diagram of the structure of the transmission assembly used in; Figure 6 for Figure 2 The assembly diagram of the digital tube and bushing used in the embodiment; Figure 7 for Figure 2 Schematic diagram of the assembly of the sliding cylinder and the transmission ring used in; Figure 8 for Figure 2 A schematic diagram of the structure of the sliding cylinder used in; Fig. 9 for Figure 2 A schematic diagram of the structure of the sounding member and the striking ring used in the invention; Fig.10 for Figure 1 The assembly cross-sectional view of the digital tube and the pressing head used in the embodiment; Fig.11 for Figure 2 A cross-sectional view of the transmission assembly used in FIG.

[0018] Description of reference numerals: 1. Pen holder; 11. Limiting part; 12. Reading port; 2. Pressing assembly; 21. Digital tube; 211. Screwing part; 212. Anti-slip groove; 22. Sliding tube; 221. Guide groove; 23. Pressing head; 231. Guide column; 232. Anti-slip hook; 24. Bushing; 3. Transmission assembly; 31. Push rod; 311. Limiting protrusion; 32. Push plate; 33. Transmission ring; 331. Guide protrusion; 34. Transmission member; 341. Guide sleeve; 35. Elastic member; 4. Injection assembly; 41. Cartridge bottle; 42. Pen refill holder; 5. Sound assembly; 51. Sound piece; 511. Gear ring; 52. Beating ring; 521. Beating arm; 53. Transmission gear; 6. Pen cap. DETAILED DESCRIPTION

[0019] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0020] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0021] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0022] It should be noted that the terms "length", "width", "height", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "head", "tail" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the 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 a limitation on the invention. The directional terms "inside" and "outside" refer to the inside and outside relative to the outline of each component itself.

[0023] It should also be noted that, unless otherwise clearly specified and limited, the terms such as "install", "connect", "connect", "fix", "set" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0024] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" may include both "above" and "below". The device may also be positioned in other different ways, and the spatially relative descriptions used here are interpreted accordingly.

[0025] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In addition, the meaning of "multiple" and "several" is two or more, unless otherwise clearly and specifically defined.

[0026] Please also read Figures 1 to 11 , the medical injection pen provided by the present invention is now described. The medical injection pen includes a pen barrel 1, a pressing assembly 2, a transmission assembly 3 and an injection assembly 4. A limiting portion 11 is provided inside the pen barrel 1, and the limiting portion 11 divides the inside of the pen barrel 1 into an installation channel and an injection channel distributed along the up and down directions, and a through hole is provided in the middle of the limiting portion 11; the pressing assembly 2 includes a digital tube 21, a sliding tube 22, and a pressing head 23. A screwing portion 211 is formed at the upper end of the digital tube 21, and the screwing portion 211 is rotatably arranged at the upper end of the installation channel. The outer periphery of the digital tube 21 is threadedly matched with the side wall of the installation channel, and the pressing head 23 is slidable up and down and is arranged in the screwing portion 211. The sliding tube 22 is only slidable along the axis of the installation channel and is arranged inside the digital tube 21, and the top end of the sliding tube 22 is transmission-connected to the pressing head 23; the transmission assembly 3 includes a push rod 31 And a transmission ring 33, the transmission ring 33 is slidably arranged inside the sliding cylinder 22 along the axis of the installation channel, and the inner wall of the sliding cylinder 22 is provided with a circumferential limiter, which is used to limit the circumferential rotation of the transmission ring 33 relative to the sliding cylinder 22; the inner wall of the transmission ring 33 is threadedly matched with the push rod 31, and the push rod 31 passes through the limiting portion 11 and extends into the injection channel. The upper end of the push rod 31 is provided with a limiting protrusion 311, which can cooperate with the upper end surface of the transmission ring 33 to limit the axial displacement of the push rod 31 when the medicine is exhausted; the injection assembly 4 has a cartridge bottle 41, which is clamped at the opening of the injection channel, and the piston of the cartridge bottle 41 abuts against the push rod 31.

[0027] It should be noted that the injection pen of this embodiment has two actions: One of the actions is to adjust the injection dose. At this time, the patient operates the screwing part 211 outward, and the digital tube 21 rotates upward. Due to the existence of the circumferential limit part, the digital tube 21 drives the sliding tube 22 to rotate, and the rotation of the sliding tube 22 drives the transmission ring 33 to rotate and rise. The inner wall of the transmission ring 33 is screwed with the push rod 31, and the transmission ring 33 will not drive the push rod 31 to move. The displacement distance of the transmission ring 33 is adjusted by screwing the digital tube 21; Another action is to inject the medicine. At this time, the patient pushes the pressing head 23 downward, and the pressing head 23 drives the sliding cylinder 22 to descend. The descent of the sliding cylinder 22 drives the transmission ring 33 to descend, and the transmission ring 33 performs unidirectional motion, driving the push rod 31 to rotate downward. The push plate 32 at the bottom end of the push rod 31 pushes the piston of the cartridge bottle 41 to descend, thereby realizing the injection of the medicine from the needle into the patient's body.

[0028] It should be noted that the up and down in this embodiment only refers to the up and down directions in the drawings.

[0029] It should be noted that the cartridge bottle 41 has a piston, and pushing the piston to change the volume of the liquid to perform the injection operation is a prior art, and the specific principle will not be repeated.

[0030] It should be noted that, after the transmission ring 33 of this embodiment is rotated out of the limit position of the inner wall of the sliding cylinder 22, or when the transmission ring 33 contacts the limit protrusion 311, it cannot be pressed down. Both combinations can prevent the transmission ring 33 from being pressed down to remind the patient to replace the new injection pen.

[0031] Compared with the prior art, the medical injection pen provided in this embodiment provides a new transmission mode. The digital tube 21 circumferentially limits the sliding tube 22 through the circumferential limiting portion 11. The sliding tube 22 is connected to the push rod 31 through the transmission ring 33. The top of the sliding tube 22 is also connected to the pressing head 23. When the patient adjusts the injection dose, the digital tube 21 is rotated. At this time, the transmission ring 33 rotates with the sliding tube 22, and the transmission ring 33 rises relative to the push rod 31. When injecting, the patient pushes the pressing head 23 downward, and the pressing head 23 drives the sliding tube 22 to descend. The sliding tube 22 The descent drives the transmission ring 33 to descend. Since the inner wall of the transmission ring 33 is threadedly connected to the push rod 31, the descent of the transmission ring 33 drives the push rod 31 to descend, pushing the liquid in the cartridge bottle 41 to change, thereby realizing injection; when the injection is completed, the limiting protrusion 311 on the upper end of the push rod 31 abuts against the transmission rod up and down, resulting in the patient being unable to twist the digital tube 21 outward, thereby reminding the patient to replace the injection pen. The whole process is simple. With each injection of the drug solution, the transmission ring 33 rises relative to the push rod 31, which can promptly remind the patient. The whole process is mechanical transmission, which is simple to operate and has high reliability.

[0032] In some embodiments, see Figure 2and Figure 5 The pressing assembly 2 further includes a bushing 24, which is fixed at the opening of the installation passage. The inner wall of the bushing 24 is provided with an internal thread, and the outer periphery of the digital tube 21 is provided with a thread groove corresponding to the internal thread, and the internal thread and the thread groove are threadedly matched. The bushing 24 is fixed in the pen barrel 1. Through the threaded match between the bushing and the digital tube 21, the inner part of the pen barrel 1 does not need to be provided with an internal thread, which can reduce the difficulty of manufacturing the pen barrel 1, and the wall thickness of the pen barrel 1 can be reduced, which is conducive to reducing the manufacturing cost of the pen barrel 1, reducing the overall weight of the injection pen, and making it convenient for patients to use.

[0033] In some embodiments, see Figure 2 and Figure 3 The transmission assembly 3 also includes a transmission member 34, an elastic member 35 and a push plate 32. One end of the transmission member 34 is connected to the upper end of the sliding cylinder 22, and the other end is slidably connected to the pressing head 23; the two ends of the elastic member 35 are respectively connected to the pressing head 23 and the transmission member 34; the push plate 32 is arranged at the end of the push rod 31 away from the pressing head 23, and the push plate 32 abuts against the piston of the cartridge bottle 41. The transmission member 34 is a connecting member, and the two ends of the transmission member 34 can be respectively adapted to the pressing head 23 and the sliding cylinder 22 to realize the transmission between the pressing head 23 and the sliding cylinder 22, so as to ensure that when the patient presses downward, the pressing head 23 drives the sliding cylinder 22 to descend normally; the elastic member 35 can automatically lift the pressing head 23 after the patient finishes pressing, and the pressing head 23 automatically recovers, thereby improving the convenience of use. The push plate 32 can increase the contact area between the push rod 31 and the piston of the cartridge bottle 41, so that the piston can be stably pushed and the stability of the injection is increased.

[0034] In some embodiments, see Fig.10 A guide sleeve 341 is provided at one end of the transmission member 34 facing the pressing head 23. The pressing head 23 is provided on the guide column 231 corresponding to the guide sleeve 341. The guide column 231 is plugged and matched with the guide sleeve 341. The elastic member 35 is sleeved on the outer periphery of the guide column 231 and the guide sleeve 341 at the same time. The setting of the guide sleeve 341 and the guide column 231 can guide the pressing head 23 to move downward. The pressing head 23 can only move along the axis of the guide sleeve 341, ensuring that the sliding cylinder 22 is driven downward stably and the normal operation of the injection pen is ensured. The guide sleeve 341 and the guide column 231 can also guide the extension direction of the elastic member 35. It is ensured that the elastic member 35 stably drives the pressing head 23 to reset.

[0035] In some embodiments, see Fig.10 The outer periphery of the end of the pressing head 23 facing the digital tube 21 is provided with an anti-detachment hook 232, and the digital tube 21 is provided with an anti-detachment groove 212 corresponding to the anti-detachment hook 232. The anti-detachment hook 232 and the anti-detachment groove 212 are engaged with each other to limit the displacement of the pressing head 23 on the axis of the installation channel. The anti-detachment hook 232 and the anti-detachment groove 212 can be engaged with each other to prevent the pressing head 23 from detaching from the digital tube 21, ensure that the pressing head 23 will not be lost, and ensure the integrity of the injection pen.

[0036] In some embodiments, see Figure 6 and Figure 8 The circumferential limiting member includes a guide protrusion 331 provided on the outer circumference of the transmission ring 33 and a guide groove 221 provided on the inner wall of the sliding cylinder 22. The guide groove 221 extends along the axis of the sliding cylinder 22. The guide protrusion 331 and the guide groove 221 slide up and down in cooperation. The guide protrusion 331 can only slide along the guide groove 221, and is limited in the circumferential direction of the transmission ring 33 to prevent the transmission ring 33 from rotating relative to the sliding cylinder 22, thereby ensuring stable transmission.

[0037] In some embodiments, see Figure 1 The outer circumference of the pen barrel 1 is provided with a reading port 12, which is connected to the installation channel, and the outer wall of the digital tube 21 is provided with a scale. The setting of the reading port 12 can display the corresponding scale of the outer circumference of the digital tube 21, so that the patient can clearly and accurately know the dose adjusted by himself when adjusting by himself, ensure that the drug dose of a single injection is appropriate, facilitate the patient's self-medication treatment, and increase the convenience and reliability of use.

[0038] In some embodiments, see Figure 2 , Figure 3 and Fig. 9 The medical injection pen further includes a sound component 5, which includes a sound piece 51, a striking ring 52 and a transmission tooth 53. The sound piece 51 is fixed in the injection channel, and a sound groove is provided at the upper end of the sound piece 51, and a tooth ring 511 is provided on the groove wall of the sound groove. The sound groove and the limiting part 11 are enclosed to form a fixed space; the striking ring 52 is rotatably arranged in the fixed space, and the inner wall of the striking ring 52 is threadedly matched with the push rod 31, and a striking arm 521 is provided on the outer periphery of the striking ring 52, and the striking arm 521 is in contact with the tooth ring 511; the transmission tooth 53 is arranged between the striking ring 52 and the sliding cylinder 22, and the upper and lower ends of the transmission tooth 53 can be respectively engaged with the striking ring 52 and the sliding cylinder 22.

[0039] It should be noted that the teeth at the upper and lower ends of the transmission tooth 53 are respectively inclined along the circumferential direction of the transmission tooth to ensure that when the sliding cylinder 22 rotates forward, the sliding cylinder 22 can drive the transmission tooth 53 to rotate, and the transmission tooth 53 drives the striking ring 52 to rotate; when the sliding cylinder 22 rotates reversely, the transmission tooth 53 and the sliding cylinder 22 will jump teeth, and the sliding cylinder 22 will not drive the striking ring 52 to rotate.

[0040] The sound assembly 5 provided in this example has three parts. The driving gear 53 enables the striking ring 52 and the sliding cylinder 22 to achieve transmission connection. When the push rod 31 descends, the push rod 31 and the striking ring 52 are threadedly matched, and the striking ring 52 will rotate. When the striking ring 52 rotates, the striking arm 521 continuously strikes the gear ring 511, making a sound to remind the patient. The sound assembly 5 can assist the patient in use, greatly improves the convenience, and ensures the stability of single adjustment and injection.

[0041] In some embodiments, see Figure 1 The transmission assembly 3 further includes a cap 6, which is covered on the outer periphery of the injection assembly 4 and connected to the bottom opening of the injection channel. The cap 6 can cover the entire injection assembly 4, thereby improving the protection and sealing effect of the cartridge bottle 41. After the cap 6 is covered, a closed space is formed to prevent the drug solution from being contaminated and ensure the quality of the drug solution.

[0042] In some embodiments, see Figure 2 The injection assembly 4 further includes a cartridge holder 42, the cartridge bottle 41 is clamped inside the cartridge holder 42, and the top of the cartridge holder 42 is clamped on the inner wall of the injection channel. The cartridge holder 42 can protect the outer periphery of the cartridge bottle 41 to prevent the cartridge bottle 41 from being damaged by bumps, thereby improving the protection of the liquid medicine. The cartridge holder 42 can also fix the cartridge bottle 41 to improve the injection stability.

[0043] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A medical injection pen, characterized in that: include: The pen barrel has a limiting portion inside, the limiting portion divides the inside of the pen barrel into an installation channel and a liquid injection channel distributed in the up-down direction, and a through hole is provided in the middle of the limiting portion; The pressing assembly comprises a digital tube, a sliding tube and a pressing head. The upper end of the digital tube forms a screwing part, the screwing part is rotatably arranged at the upper end of the installation channel, the outer periphery of the digital tube is threadedly matched with the side wall of the installation channel, the pressing head is slidably arranged on the screwing part, the sliding tube is only slidably arranged inside the digital tube along the axis of the installation channel, and the top end of the sliding tube is transmission-connected with the pressing head; The transmission assembly comprises a push rod and a transmission ring. The transmission ring is slidably arranged inside the sliding cylinder along the axis of the installation channel. The inner wall of the sliding cylinder is provided with a circumferential limiter, and the circumferential limiter is used to limit the rotation of the transmission ring relative to the sliding cylinder in the circumferential direction. The inner wall of the transmission ring is threadedly matched with the push rod. The push rod passes through the limiter and extends into the injection channel. The upper end of the push rod is provided with a limit protrusion, and the limit protrusion can be matched with the upper end surface of the transmission ring to limit the axial displacement of the push rod when the liquid medicine is exhausted. as well as The injection assembly comprises a cartridge bottle which is clamped at the opening of the injection channel, and the piston of the cartridge bottle is in contact with the push rod.

2. The medical injection pen according to claim 1, characterized in that: The pressing assembly also includes a bushing, which is fixed at the opening of the installation channel. The inner wall of the bushing is provided with an internal thread, and the outer periphery of the digital tube is provided with a thread groove corresponding to the internal thread, and the internal thread is threadably matched with the thread groove.

3. The medical injection pen according to claim 1, characterized in that: The transmission assembly also includes: A transmission member, one end of which is connected to the upper end of the sliding cylinder, and the other end of which is slidably connected to the pressing head; An elastic member, two ends of which are respectively connected to the pressing head and the transmission member; and A push plate is arranged at one end of the push rod away from the pressing head, and the push plate abuts against the piston of the cartridge bottle.

4. The medical injection pen according to claim 3, characterized in that: A guide sleeve is provided at one end of the transmission member facing the pressing head. The pressing head is arranged on a guide column corresponding to the guide sleeve. The guide column is plug-fitted with the guide sleeve. The elastic member is simultaneously sleeved on the outer periphery of the guide column and the guide sleeve.

5. The medical injection pen according to claim 3, characterized in that: An anti-detachment hook is provided on the outer periphery of one end of the pressing head facing the digital tube, and the digital tube is provided with an anti-detachment groove corresponding to the anti-detachment hook. The anti-detachment hook is engaged with the anti-detachment groove to limit the displacement of the pressing head on the axis of the installation channel.

6. The medical injection pen according to claim 1, characterized in that: The circumferential limiter comprises a guide protrusion arranged on the outer circumference of the transmission ring and a guide groove arranged on the inner wall of the sliding cylinder. The guide groove extends along the axis of the sliding cylinder, and the guide protrusion and the guide groove are slidably matched up and down.

7. The medical injection pen according to claim 1, characterized in that: A reading port is provided on the outer circumference of the pen holder, the reading port is communicated with the installation channel, and a scale is provided on the outer wall of the digital tube.

8. The medical injection pen according to claim 1, characterized in that: The medical injection pen further comprises a sound component, and the sound component comprises: A sounding member is fixedly arranged in the injection channel, a sounding groove is provided at the upper end of the sounding member, a toothed ring is provided on the groove wall of the sounding groove, and the sounding groove and the limiting portion are enclosed to form a fixed space; a striking ring rotatably disposed in the fixed space, the inner wall of the striking ring being in threaded engagement with the push rod, a striking arm being disposed on the outer periphery of the striking ring, the striking arm being in contact with the gear ring; and The transmission tooth is arranged between the striking ring and the sliding cylinder, and the upper and lower ends of the transmission tooth can be respectively engaged with the striking ring and the sliding cylinder.

9. The medical injection pen according to claim 1, characterized in that: The transmission assembly also includes a pen cap, which is arranged on the outer periphery of the injection assembly and connected to the bottom opening of the injection channel.

10. The medical injection pen according to claim 1, characterized in that: The injection assembly also includes a core frame, the cartridge bottle is clamped inside the core frame, and the top of the core frame is clamped on the inner wall of the injection channel.

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