CN115177816A

CN115177816A - Pen type injector

Info

Publication number: CN115177816A
Application number: CN202210791387.1A
Authority: CN
Inventors: 王峰; 俞晓琳
Original assignee: Juyi Kerui Medical Technology Shanghai Co ltd
Current assignee: Juyi Kerui Medical Technology Shanghai Co ltd
Priority date: 2022-07-06
Filing date: 2022-07-06
Publication date: 2022-10-14

Abstract

The invention relates to the technical field of drug administration and injection, and discloses a pen-type injector which comprises a cartridge, wherein one end of the cartridge is provided with an injection needle; a main body disposed at one end of the cartridge; the drug delivery mechanism is arranged in the main body and comprises a plug part and a connecting part, wherein the plug part and the connecting part are matched with the inner wall of the drug cylinder in size; the calibration mechanism extends into the main body and is matched with the inner wall surface of the main body, and the calibration mechanism comprises a dose setter sleeved on the outer side of the connecting part; the trigger is arranged at one end of the main body, which is back to the medicine cylinder, and is connected with the dose setter; the rewinding ring is sleeved on the outer side of the medicine cylinder and connected to the connecting part to drive the plug part to reset. The pen-type administration injector can carry out multiple injections scientifically and quantitatively, so that the injection requirement that a user can carry out multiple injections without dosage by filling once is met, the times of filling medicines are reduced, and the time cost and the waste of human resources of the injection are reduced.

Description

Pen type injector

Technical Field

The invention relates to the technical field of drug administration and injection, in particular to a pen-type injector.

Background

The pen type medicine-feeding injection device is one device combining medicine and syringe and consists of mainly trigger, main body, driving unit, power accumulating unit, medicine cartridge and needle. The medicament is stored in a cartridge, typically in conjunction with a particular injection device. When in use, the safety cap is taken down, the disposable injection needle is arranged and the air is exhausted, and the medicine delivery is realized by adjusting the required dosage and driving the trigger. At present, the conventional injection device generally adopts a structure that medicine is loaded once and is directly injected after a dose is set. The injection amount of the medicine is single and fixed, the setting of the dose is unidirectional, the delivery amount of the medicine is fixed every time, the medicine cannot be scientifically and quantificationally controlled and delivered for multiple times, and the delivery requirement of a customer for multiple injections without the dose cannot be met; moreover, the medicine needs to be filled for many times of injection, which wastes human resources and improves the time cost of injection.

Disclosure of Invention

The purpose of the invention is: the pen-type injector is provided, so that the pen-type administration injector can carry out multiple injections scientifically and quantitatively, the injection requirement that a user can carry out multiple injections without dosage by single filling is met, the times of filling medicines are reduced, and the time cost and the waste of human resources for injection are reduced.

In order to achieve the above object, the present invention provides a pen injector comprising:

a cartridge having an injection needle disposed at one end;

a body arranged at an end of the cartridge facing away from the injection needle;

the drug delivery mechanism is arranged in the main body and comprises a plug part which is matched with the inner wall of the drug cylinder in size, one end of the plug part extends into the drug cylinder, and the drug delivery mechanism also comprises a connecting part which is connected with the plug part;

the calibration mechanism extends into the main body and is matched with the inner wall surface of the main body, and the calibration mechanism comprises a dose setter sleeved on the outer side of the connecting part;

a trigger disposed at an end of the body facing away from the cartridge, the trigger being connected to the dose setter;

the rewinding ring is sleeved on the outer side of the medicine cylinder and connected with the connecting part so as to drive the plug part to reset.

Compared with the prior art, the pen-type injector provided by the embodiment of the invention has the beneficial effects that: before the injection, put into the medicine of treating the injection in the cartridge case, install the cartridge case on rewinding the ring again, it resets to rotate rewinding the ring to fill in the portion, pressurize connecting portion, rotate the trigger, the direction that drives calibration mechanism's dose setting ware orientation cartridge case moves, reach and predetermine calibration value after, press the trigger towards the cartridge case direction, the trigger passes through dose setting ware trigger connecting portion, make connecting portion move towards the cartridge case direction, promote the fill in the portion and remove and promote the medicine to the syringe needle direction in the cartridge case, finally pour into the human body through the syringe needle. After the injection is completed again, the trigger drives the dose setter to reset, so that the dose setter returns to the initial position where the injection is not performed, and the trigger can be rotated again to calibrate the injection value of the next time. The device enables the pen type drug delivery injector to carry out multiple injections scientifically and quantitatively, so that the injection requirement that a user can carry out multiple injections without dosage after single filling is met, the times of filling drugs are reduced, and the time cost of injection and the waste of human resources are reduced.

According to the pen-type injector disclosed by the embodiment of the invention, one side of the scale is abutted against the dose setter, the scale is arranged in the trigger, and the trigger is provided with an observation window for displaying the reading of the scale.

In the pen-type injector according to the embodiment of the present invention, the outer sides of the dose setter and the scale are sleeved with a biasing spring for resetting, and the inner wall surface of the body is provided with a mounting plane for supporting the biasing spring.

According to the pen-type injector provided by the embodiment of the invention, the connecting part comprises a clutch, an outer driving shaft and an inner driving shaft, the clutch is connected with the dose setting device, the clutch is sleeved on the outer side of the outer driving shaft, the outer driving shaft is sleeved on the outer peripheral surface of the inner driving shaft and can drive the inner driving shaft, and the inner driving shaft is connected with the plug part.

In the pen injector according to the embodiment of the present invention, a torsion spring is provided between the inner drive shaft and the outer drive shaft, and the torsion spring is connected to the inner drive shaft and the drive shaft, respectively.

In the pen injector according to the embodiment of the present invention, a plunger is connected to an inside of the inner drive shaft, and one end of the plunger is connected to the plug portion.

In the pen injector according to the embodiment of the present invention, an outer rib is provided on an outer end surface of the outer drive shaft in a direction close to the trigger, and a flat wall is provided close to the cartridge, an inner rib matching with the outer rib is provided on an inner wall surface of the clutch, and an inner wall groove matching with the outer rib is also provided on an inner wall of the scale.

According to the pen-type injector provided by the embodiment of the invention, the dose setter is provided with the first clamping groove, and one end of the clutch facing the dose setter is provided with the first clamping buckle matched with the first clamping groove.

In the pen-type injector according to the embodiment of the invention, the inner wall surface of the main body is provided with a plurality of tickler ribs, and the outer wall surface of the dose setter is provided with an elastic contact piece matched with the tickler ribs.

According to the pen-type injector provided by the embodiment of the invention, one end of the trigger, which is close to the dose setter, is provided with the second buckle groove, and one end of the dose setter, which faces the trigger, is provided with the second buckle matched with the second buckle groove.

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

Drawings

FIG. 1 is a schematic exploded view of a pen injector according to an embodiment of the present invention;

figure 2 is a schematic structural view of an exploded body of a pen injector according to an embodiment of the present invention;

FIG. 3 is a schematic structural view of a pen injector disassembled dose setter of an embodiment of the present invention;

FIG. 4 is a schematic structural view of a disassembled trigger of the pen injector according to the embodiment of the present invention;

figure 5 is a structural schematic of an exploded rewind ring of a pen injector in accordance with an embodiment of the present invention;

figure 6 is a schematic structural view of an exploded ratchet sleeve of a pen injector in accordance with an embodiment of the present invention;

FIG. 7 is a schematic structural view of an exploded scale of a pen injector in accordance with an embodiment of the present invention;

figure 8 is a schematic structural view of a disassembled clutch of the pen injector according to an embodiment of the present invention;

figure 9 is a schematic structural view of an exploded outer drive wheel of a pen injector according to an embodiment of the present invention;

figure 10 is a schematic view of the structure of the disassembled stopper of the pen injector according to the embodiment of the present invention.

In the figure, 1, the cartridge; 2. an injection needle; 3. a safety helmet; 4. a main body; 41. a third snap groove; 42. a clutch groove; 44. a tick rib; 45. a mounting plane; 5. a dose setter; 51. a stop surface; 52. a first snap groove; 53. a finger portion; 54. an elastic contact piece; 55. a second buckle; 6. a trigger; 61. a threaded rib; 62. an observation window; 63. a second snap-fit groove; 7. a rewinding ring; 71. ratchet teeth; 72. a counter bore; 73. a bump; 8. a ratchet sleeve; 81. a positioning column; 82. a third buckle; 9. a scale; 91. a graduated scale; 92. an inner wall groove; 10. a biasing spring; 11. a clutch; 111. a first buckle; 112. a U-shaped rib; 113. an inner rib; 12. an outer drive shaft; 121. an outer rib; 122. a flat wall; 13. an inner drive shaft; 14. a torsion spring; 15. a plunger; 151. a long groove; 16. a plug portion.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

In the description of the present invention, it should be understood that the orientation or positional relationship referred to in the description of the orientation, such as the upper, lower, front, rear, left, right, etc., is based on the orientation or positional relationship shown in the drawings, and is only for convenience of description and simplification of description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.

In the description of the present invention, the meaning of a plurality of means is one or more, the meaning of a plurality of means is two or more, and larger, smaller, larger, etc. are understood as excluding the number, and larger, smaller, inner, etc. are understood as including the number. If there is a description of first and second for the purpose of distinguishing technical features only, this is not to be understood as indicating or implying a relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of technical features indicated.

In the description of the present invention, unless otherwise explicitly limited, terms such as arrangement, installation, connection and the like should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above terms in the present invention in combination with the specific contents of the technical solutions.

Referring to fig. 1, a pen-type injector according to a preferred embodiment of the present invention includes a cartridge 1, wherein an injection needle 2 for injecting medicine is disposed at one end of the cartridge 1, a safety cap 3 is further connected to the cartridge 1 at an outer side of the injection needle 2, and the safety cap 3 is used for protecting the injection needle 2 when the injector is not in use, so as to prevent accidents. One side of the medicine cylinder 1 back to the injection needle 2 is fixed on a rewinding ring through threads, the rewinding ring adopts a step arrangement, a holding part with a larger diameter is used for rotating and resetting, and a connecting part with a smaller diameter is used for connecting the main body of the device, so that the main body is connected to one end of the rewinding ring back to the medicine cylinder 1.

As shown in fig. 1, a pen-type injector according to a preferred embodiment of the present invention further includes a main body 4, the main body 4 is disposed at an end of the drug cartridge 1 opposite to the injection needle 2, the main body 4 is configured as a hollow cylinder, and the inner wall surface of the main body 4 is provided with various grooves and ribs to meet the assembly and working requirements of different components; the inside of main part 4 is provided with the mechanism of dosing, and the mechanism of dosing includes cock portion 16 and connecting portion, and wherein cock portion 16 and the size cooperation of the inner wall of medicine section of thick bamboo 1 and one end stretch into in the medicine section of thick bamboo 1, and the connecting portion then connects cock portion 16 in the outside of medicine section of thick bamboo 1 in order to provide the power of business turn over medicine section of thick bamboo 1 to cock portion 16, and the connecting portion still is connected with other parts of syringe. The calibration mechanism is arranged in the main body 4 and used for determining the dose of the injector injected each time, extends into the main body 4 and is matched with the inner wall surface of the main body 4, the calibration mechanism comprises a dose setter 5 sleeved on the outer side of the connecting part, and the stroke of the dose setter 5 moving in the main body 4 can determine the dose required by one-time injection; the dose setter 5 is connected to a trigger 6, the trigger 6 is arranged at an end of the body 4 facing away from the cartridge 1, the trigger 6 is shell-shaped and arranged at an end of the body 4, and the trigger 6 can change the stroke of the dose setter 5 when pressed or rotated to adjust the stroke of the dose setter 5 moving in the body 4.

Before the injection, put into the medicine of treating the injection in cartridge case 1, install cartridge case 1 on rewinding ring 7 again, it resets to rotate rewinding ring 7 cock portion 16 and compresses the pressurization to the connecting portion, rotate trigger 6, drive calibration mechanism's dose setting device 5 and move towards cartridge case 1's direction, after reaching preset calibration value, press trigger 6 towards cartridge case 1 direction, trigger 6 triggers the connecting portion through dose setting device 5, make the connecting portion move towards cartridge case 1 direction, promote cock portion 16 and remove and promote the medicine to syringe needle 2 direction in cartridge case 1, finally inject into the human body through syringe needle 2. After the injection is completed again, the trigger 6 of the plug part 16 drives the dose setter to reset, and the dose setter returns to the initial position of the plug part 16 where the injection is not performed, and at this time, the trigger 6 can be rotated again to calibrate the injection value of the next time.

As shown in fig. 5, the pen-type injector according to the preferred embodiment of the present invention further includes a rewinding ring 7, wherein the rewinding ring 7 is sleeved on the outside of the medicine container 1 and connected to the connecting portion to drive the plug portion 16 to reset. In particular, the side of the rewinding ring 7 facing the injection needle 2 is provided with a thread for fixing the safety cap 3. The outer circumferential surface of the end of the rewinding ring 7 with the smaller diameter is sleeved with a ratchet sleeve 8, the outer circumferential surface of the rewinding ring 7 facing the ratchet sleeve 8 is provided with two ratchet teeth 71 arranged in opposite directions, and the inner circumferential surface of the ratchet sleeve 8 is provided with two positioning posts 81 matched with the ratchet teeth 71, so that the ratchet sleeve 8 can be stably fixed on the rewinding ring 7. The ratchet sleeve 8 is provided with a third buckle 82 in an upward direction, one end of the main body 4 close to the ratchet sleeve 8 is provided with a third buckle groove 41, the third buckle 82 and the third buckle groove 41 are matched to enable the ratchet sleeve 8, the rewinding ring 7 and the main body 4 to form a synchronous component, and the main body 4 provides unidirectional rotation limitation in the rotation movement process of the rewinding ring 7.

In some embodiments of the present invention, as shown in fig. 7, the calibration mechanism further includes a scale 9, the scale 9 is disposed in a spiral shape, and scales 91 are disposed on an outer end surface of the scale 9 and are uniformly spaced apart from each other. A stop surface 51 is provided on the end surface of the dose setter 5 adjacent the dial 9 and the end of the dial 9 adjacent the dose setter 5 abuts the stop surface 51 to be restrained by the dose setter 5 during movement. The scale 9 is arranged in the trigger 6, the inner wall surface of the trigger 6 is provided with a thread rib 61, and the thread rib 61 is matched with the rotation angle and the length of the scale 9, so that the scale 9 can move axially along with the rotation of the trigger 6; the trigger 6 is further provided with an observation window 62 for displaying the reading of the scale 9, so that a user can conveniently check the reading on the scale 9 when rotating the trigger 6 to accurately grasp the medicine amount required by the injection.

As shown in figure 1, in some embodiments of the invention, the dose setter 5 and the outside of the scale 9 are fitted with a biasing spring 10 for return, and a mounting plane 45 supporting the biasing spring 10 is set on the inner wall surface of the body 4; the biasing spring 10 is forced towards the mounting plane 45 when the dose setter 5 and the scale 9 are rotationally displaced towards the cartridge 1 and then loses its restraining force on the trigger 6 after the trigger 6 is depressed to complete the injection, the biasing spring 10 acting in the opposite direction to force the dose setter 5 and the scale 9 back into the initial position ready for the next calibration injection.

In some embodiments of the invention, as shown in fig. 1, the coupling part comprises a clutch 11, an outer drive shaft 12 and an inner drive shaft 13, the clutch 11 being coupled to the dose setter 5 and being axially movable with the dose setter 5, the clutch 11 being located on the side of the dose setter 5 facing in the direction of the recoil ring 7. The inner wall surface of the dose setter 5 is provided with a first snap groove 52, the end of the clutch 11 facing the dose setter 5 is provided with a first snap 111 cooperating with the first snap groove 52, the first snap 111 groove 52 is arranged in a ring around the inner circumference of the dose setter 5, this arrangement enables a synchronous axial movement of the dose setter 5 and the clutch 11, but does not restrict the axial rotation of the clutch 11.

In some embodiments of the invention, the biasing spring 10 may also be provided in the axial spacing between the outer drive shaft 12 and the clutch 11, and may also act to reset the clutch 11, the dose setter 5 and the scale 9 after an injection.

As shown in fig. 2, the inner wall surface of the body 4 is provided with a clutch groove 42, and the outer end surface of the clutch 11 is provided with a U-shaped rib 112 engaged with the clutch groove 42; when the clutch 11 is in a holding state, i.e. the trigger 6 is rotated to adjust the amount of medicine to be injected, the U-shaped ribs 112 are positioned outside the clutch grooves 42, and the clutch grooves 42 do not limit the axial rotation of the clutch 11; when the clutch 11 is in the released state, i.e. when the trigger 6 is pressed to start the injection of the syringe, the clutch 11 is axially displaced and the U-shaped ribs 112 enter the clutch grooves 42, limiting the axial rotation of the clutch 11.

As shown in fig. 2, a dose setting groove 43 is provided on the inner wall surface of the body 4, and a finger 53 which engages with the dose setting groove 43 is provided on the end surface of the dose setting device 5 facing the rewinding ring 7. When the trigger 6 rotates to adjust the injection dosage, the dosage setter 5 rotates along with the trigger to adjust the self stroke; when the trigger 6 is depressed to perform an injection, the fingers 53 enter the dose setter 43, causing both axial and rotational movement of the dose setter 5 to be limited.

As shown in fig. 8, the clutch 11 is sleeved outside the outer driving shaft 12, the outer side end face of the outer driving shaft 12 is provided with an outer rib 121 close to the trigger 6 and a flat wall 122 close to the medicine cartridge 1, the inner wall face of the clutch 11 is provided with an inner rib 113 matched with the outer rib 121, when the clutch 11 is in a holding state, that is, the trigger 6 rotates to adjust the medicine amount to be injected, the inner rib 113 of the clutch 11 is abutted with the outer rib 121 of the outer driving shaft 12 to limit the rotation of the outer driving shaft 12; when the clutch 11 is in the released state, i.e. the trigger 6 is pressed to start injection of the syringe, the clutch 11 is moved axially, the inner ribs 113 of the clutch 11 are disengaged from the outer ribs 121 of the outer drive shaft 12, and the outer drive shaft 12 is released and starts to rotate. The inner wall of the scale 9 is also provided with an inner wall groove 92 which cooperates with the outer rib 121 so that rotation of the outer drive shaft 12 causes the scale 9 to rotate together and move axially, and when the end of the scale 9 rotates to abut the stop surface 51 of the dose setter 5, the outer drive shaft 12 stops rotating and the injection is completed.

As shown in fig. 1, the outer driving shaft 12 is sleeved on the outer circumference of the inner driving shaft 13 and can drive the inner driving shaft 13, specifically, a torsion spring 14 is arranged between the inner driving shaft 13 and the outer driving shaft 12, the torsion spring 14 is respectively connected with the inner driving shaft 13 and the driving shaft, when the outer driving shaft 12 rotates, the torsion force is transmitted to the inner driving shaft 13 through the torsion spring 14, the inner driving shaft 13 is connected with the plug part 16, a certain axial displacement occurs during the rotation, and the medicine in the medicine cartridge 1 can be discharged out of the medicine cartridge 1 through the injection needle 2, so that the injection is completed.

As shown in fig. 5, a counterbore 72 is provided on an end surface of the rewinding ring 7 facing the torsion spring 14, one end of the torsion spring 14 is fixed in the counterbore 72, and the rewinding ring 7 drives the torsion spring 14 to rotate and retract in the rotating process, so that the resetting of the connecting part is completed.

As shown in fig. 10, in some embodiments of the present invention, a plunger 15 is connected to the inside of the inner driving shaft 13, one end of the plunger 15 is connected to a plug portion 16, the plug portion 16 is equal in length and connected with the inner driving shaft 13, threads are provided on the outside of the plunger 15, threads are provided on the inner wall of the inner driving shaft 13 to match with the plunger 15, axial movement of the plunger 15 is provided when the torsion spring 14 rotates the inner driving shaft 13, and the plunger 15 moves the plug portion 16 in the direction of the injection needle 2 in the drug cartridge 1, thereby completing the drug delivery function.

As shown in fig. 10, two long slots 151 are respectively opened at the upper and lower ends of the plunger 15, two protrusions 73 matched with the long slots 151 are opened at one end of the rewinding ring 7 facing the plunger 15, and the protrusions 73 are arranged to enable the plunger 15 and the rewinding ring 7 to rotate together during rewinding, so that the plunger 15 retracts into the inner driving shaft 13, and the plug 16 withdraws to the inlet of the medicine cartridge 1. It will be appreciated that the two opposing slots 151 of the plunger 15 may be configured to have any mating shape that limits axial rotation but allows axial movement, and is not limited in any way. The ratchet teeth 71 of the rewinding ring 7 have no deformable space, can prevent the idle stroke movement of the plunger 15 of the medicine cylinder 1 generated in the process of storing force again on the rewinding ring 7 after the medicine cylinder 1 is loaded, ensures the safe and reliable protection effect of the injection dosage precision, and prevents various pathological risks caused by insufficient injection dosage of a user due to the defect of the injection dosage formed by the idle stroke of the plunger 15.

In some embodiments of the invention, as shown in fig. 2, the inner wall of the body 4 is provided with a plurality of click ribs 44, the outer wall of the dose setter 5 is provided with resilient contact 54 cooperating with the click ribs 44, and the click ribs collide with the resilient contact 54 during dose setting to generate a sound and tactile feedback synchronized with the set dose. The dose setting and injection scale system provides sound and tactile feedback for a user in a dose setting step and a medicine injection step, prompts the user for the feedback on the magnitude speed of a setting unit in dose setting and injection, provides first feedback information for the user to grasp the injection process in time and terminate the injection at any time.

In some embodiments of the invention, the click feature may also be designed to provide a moving contact between circumferentially spaced ribs on the inside of the trigger 6 and the outer ribs 121 of the outer drive shaft 12, providing an audible and tactile feedback synchronized with the setting of a dose.

In some embodiments of the invention, as shown in fig. 4, the trigger 6 has a second detent groove 63 at an end thereof adjacent to the dose setter 5, the dose setter 5 has a second detent 55 at an end thereof facing the trigger 6 for engaging the second detent groove 63, and the engagement of the second detent 55 with the second detent 55 groove 63 allows the trigger 6 and the dose setter 5 to be configured to rotate and move synchronously, such that the distance between the stop surface 51 of the dose setter 5 and the scale 9 can be set when the trigger 6 is rotated, and the distance is proportional to the stroke of the plunger 15 during the injection, thereby controlling the stroke of the plunger 15 in the cartridge 1 and hence the drug output of the cartridge 1.

The working process of the invention is as follows: before injection, the medicine to be injected is put into the medicine cartridge 1, then the medicine cartridge 1 is arranged on the rewinding ring 7, the trigger 6 is rotated to drive the dose setter 5 of the calibration mechanism and the clutch 11 connected with the dose setter 5 to move towards the direction of the medicine cartridge 1, and at the moment, the outer driving shaft 12 cannot rotate along with the movement; after reaching the preset calibration value, the trigger 6 is pressed towards the direction of the medicine cartridge 1, the trigger 6 pushes the clutch 11 through the dose setter 5, the clutch 11 is in contact with the limit of the outer driving shaft 12, the outer driving shaft 12 starts to rotate to drive the inner driving shaft 13 to rotate, the plunger 15 moves towards the direction of the medicine cartridge 1, the plug part 16 is pushed to move in the medicine cartridge 1 and push the medicine to the direction of the injection needle 2, and finally the medicine is injected into a human body through the injection needle 2. After the injection is completed again, the biasing spring 10 drives the trigger 6 and the dose setter 5 to reset to the initial position before the injection, and at this time, the trigger 6 can be rotated again to calibrate the next injection value.

In summary, the embodiment of the present invention provides a pen-type injector, which enables the pen-type administration injector to perform multiple injections scientifically and quantitatively, so as to meet the injection requirement that a user can perform multiple injections without dosage by filling once, reduce the times of filling drugs, and reduce the time cost of injection and the waste of human resources.

The above is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and substitutions can be made without departing from the technical principle of the present invention, and these modifications and substitutions should also be regarded as the protection scope of the present invention.

Claims

1. A pen injector, comprising:

a cartridge having an injection needle disposed at one end thereof;

the drug delivery mechanism is arranged in the main body and comprises a plug part which is matched with the inner wall of the drug cylinder in size, and one end of the plug part extends into the drug cylinder;

2. The pen injector according to claim 1, characterized in that: the calibration mechanism further comprises a scale, one side of the scale is abutted against the dose setter, the scale is arranged in the trigger, and an observation window for displaying the reading of the scale is arranged on the trigger.

3. The pen injector according to claim 2, characterized in that: the outer sides of the dose setter and the scale are sleeved with a bias spring for resetting, and the inner wall surface of the main body is provided with a mounting plane for supporting the bias spring.

4. The pen injector according to claim 2, characterized in that: the connecting part comprises a clutch, an outer driving shaft and an inner driving shaft, the clutch is connected with the dose setting device, the clutch is sleeved on the outer side of the outer driving shaft, the outer driving shaft is sleeved on the outer peripheral surface of the inner driving shaft and can drive the inner driving shaft, and the inner driving shaft is connected with the plug part.

5. The pen injector according to claim 4, characterized in that: and a torsion spring is arranged between the inner driving shaft and the outer driving shaft and is respectively connected with the inner driving shaft and the outer driving shaft.

6. The pen injector according to claim 4, characterized in that: and a plunger is connected inside the inner driving shaft, and one end of the plunger is connected with the plug part.

7. The pen injector according to claim 4, characterized in that: an outer rib close to the trigger direction and a flat wall close to the medicine cartridge are arranged on the end face of the outer side of the outer driving shaft, an inner rib matched with the outer rib is arranged on the inner wall face of the clutch, and an inner wall groove matched with the outer rib is also arranged on the inner wall of the scale.

8. The pen injector according to claim 4, characterized in that: the dose setting device is provided with a first buckle groove, and one end of the clutch facing the dose setting device is provided with a first buckle matched with the first buckle groove.

9. The pen injector according to claim 2, characterized in that: the inner wall surface of the main body is provided with a plurality of tick ribs, and the outer wall surface of the dose setting device is provided with an elastic contact piece matched with the tick ribs.

10. The pen injector according to claim 1, characterized in that: and a second buckle groove is formed in one end, close to the dose setter, of the trigger, and a second buckle matched with the second buckle groove is arranged at one end, facing the trigger, of the dose setter.