Automatic injection pen

Abstract

The invention discloses an automatic injection pen, which relates to the technical field of injection pens and comprises a pen shell, a pen cap, an injection mechanism, a dose adjusting mechanism, an energy storage mechanism, a clutch mechanism and a push rod non-return mechanism, the pen shell comprises an upper pen shell and a lower pen shell which are connected with each other; the end of the upper pen shell is rotationally connected with a knob, and a button is clamped to the end of the knob in a limiting mode. The pen cap is sleeved on the surface of the end part of the lower pen shell; after injection is finished every time, the push rod is kept in the original position and tightly abuts against the piston in the clamping type bottle, and during next injection, only dosage adjustment is needed, emptying operation is not needed, and automatic multi-time adjustment injection is achieved; meanwhile, the dosage adjusting operation and the force applying energy storage operation are synchronously carried out, and after liquid medicine injection is completed, the injector can return to the original position, so that convenience is provided for next injection, and the whole injection operation is simpler and more convenient.

Description

Technical Field

[0001] The present invention relates to the technical field of injection pens, and more particularly to automatic injection pens. Background Art

[0002] An automatic injection pen is a convenient and easy-to-operate medical device, which is widely used in the medical field. In clinical practice, automatic injection pens are widely used in the treatment of various diseases, such as diabetes, rheumatoid arthritis, etc.; The design of the automatic injection pen aims to simplify the drug injection process and improve the convenience and accuracy of self-injection for patients. Compared with traditional syringes, automatic injection pens usually have functions such as pre-filled drugs and one-button injection. Users only need to unscrew the cap, attach the needle, set the dose, and then press the button to complete the injection, which is simple and convenient to operate; This design makes the automatic injection pen particularly suitable for patients who need frequent injections, such as diabetes patients. Patients can easily perform drug injections at home without the help of professionals, reducing the waste of medical resources, improving the treatment convenience and compliance of patients, and helping to reduce the risk of medication errors and cross-infections. Since the drugs are pre-filled and the dose is set accurately, patients can avoid problems caused by incorrect drug preparation or inaccurate injection dose during use. At the same time, it also helps to improve the stability and preservation of drugs. Drugs are usually loaded into the automatic injection pen during production, avoiding multiple openings and contacts, reducing the possibility of drug contamination or oxidation, and being conducive to maintaining the effectiveness and stability of drugs; However, after using the same bottle of liquid medicine and for the first injection, the existing automatic injection pen needs to push the push rod back to the original position. Then, for the next injection, it is necessary to first adjust the scale, perform an emptying operation. After completing the emptying operation, then adjust the scale to the dose value to be injected. Although the operation is more convenient compared to traditional syringes, for patients who need to inject drugs for a long time, there are still certain inconveniences. Therefore, it is necessary to design a new type of automatic injection pen to solve the above problems. Summary of the Invention

[0003] The purpose of the present invention is to design an automatic injection pen to solve the problem that the existing automatic injection pen, when injecting drugs using the same bottle of liquid medicine, needs to first perform emptying and then adjust the scale to the dose value to be injected, and the operation is still not convenient enough as mentioned in the above background art.

[0004] To achieve the above invention purpose, the present invention provides the following technical solutions: An automatic injection pen, comprising a pen shell, a pen cap, an injection mechanism, a dose adjustment mechanism, an energy storage mechanism, a clutch mechanism, and a push rod check mechanism; The pen shell includes an upper pen shell and a lower pen shell that are connected to each other; a knob is rotatably connected to the end of the upper pen shell, and a button is limited and engaged with the end of the knob; the pen cap is sleeved on the surface of the end of the lower pen shell; The injection mechanism includes a cartridge installed inside the lower pen shell and a push rod installed inside the upper pen shell. The bottom of the push rod abuts against the cartridge, a connecting rod is sleeved on the outer surface of the push rod in a limited manner, and the top of the connecting rod is limited and engaged with the button; The dose adjustment mechanism includes an adapter tube provided on the outer surface of the connecting rod. The bottom of the connecting rod is clamped at the bottom of the adapter tube. A spiral scale disk is limited and engaged with the outer surface of the adapter tube. The spiral scale disk is threadedly connected inside the upper pen shell, and an observation port matching the spiral scale disk is provided on the upper pen shell; an upper transmission assembly is provided between the inside of the knob and the connecting rod, and a lower transmission assembly is provided between the bottom of the adapter tube and the push rod; The energy storage mechanism includes a torsion spring provided between the connecting rod and the adapter tube. The bottom of the torsion spring is clamped with the adapter tube, and the top of the torsion spring is clamped on a positioning plate, and the positioning plate is fixed inside the upper pen shell; The clutch mechanism includes a switch member provided between the adapter tube and the lower transmission assembly. A second spring is provided between the switch member and the adapter tube, and a first spring is provided between the button and the positioning plate.

[0005] Through the design of the above structure, while the automatic injection pen realizes dose adjustment and automatic injection, a check valve design is also carried out on the push rod, which can prevent the push rod from retracting. In this way, after each injection use, the push rod will still tightly abut against the piston of the cartridge, and the dose scale disk will automatically return to its original position. For the next injection of the same cartridge, only need to continue to adjust the knob to the dose value to be injected, without the need for an evacuation operation, further saving the injection steps and realizing automatic multiple injection operations, which are simple and convenient.

[0006] Preferably, the upper transmission assembly includes a lining sleeve that is limited and engaged with the surface of the connecting rod. A first rack is provided on the lining sleeve. An outer lining sleeve is sleeved on the surface of the lining sleeve. A second rack is provided on the outer lining sleeve. The first rack and the second rack are meshed with each other; the outer lining sleeve is clamped with the inner wall of the knob; through the design of the above structure, it is realized that by rotating the knob, the lining sleeve is driven to rotate, the lining sleeve rotation drives the connecting rod to rotate, and the connecting rod rotation drives the adapter tube to rotate.

[0007] Preferably, two sets of arc-shaped slots that are centrosymmetric are provided on the surface of the outer bushing. Two arc-shaped inserts are symmetrically arranged inside the knob, and the inserts cooperate with the slots; through the design of the inserts and slots, the rotation of the knob drives the rotation of the outer bushing. A first spring strip is fixed on each set of slots, and the two first spring strips are centrosymmetrically designed. A first annular sawtooth that is in limit abutment with the tail of the first spring strip is fixed on the inner wall of the upper pen shell; through the design of the first spring strip and the first annular sawtooth, it can be ensured that the knob can only rotate around a single direction, that is, it can avoid the patient's operation error and make the adjustment unique and simple.

[0008] Preferably, the lower transmission assembly includes a movable sleeve that is limit-inserted at the bottom of the connecting pipe. A third rack is fixed to the bottom of the movable sleeve; the bottom of the movable sleeve abuts against the docking sleeve, and a fourth rack is fixed to the top of the docking sleeve. The third rack and the fourth rack mesh with each other. A third spring is provided between the docking sleeve and the connecting pipe; a fifth rack is provided inside the docking sleeve. A rotating sleeve is threadedly connected to the surface of the push rod, and a sixth rack is fixed to the surface of the rotating sleeve. The fifth rack and the sixth rack mesh with each other; the rotating sleeve is inserted at the bottom end inside the upper pen shell; through the design of the movable sleeve, the docking sleeve, the rotating sleeve, and the second spring and the third spring, when the connecting pipe rotates, it will drive the third rack to rotate. At this time, since the rotating sleeve does not move, the docking sleeve will not move either. Therefore, the movable sleeve will compress the second spring for skip tooth movement to ensure the normal rotation of the connecting pipe.

[0009] Preferably, the switch member includes a seventh rack fixed to the bottom of the connecting pipe. An opening that cooperates with the seventh rack is provided on the movable sleeve. An eighth rack is fixed to the inner side of the top of the docking sleeve. The seventh rack and the eighth rack mesh with each other; the second spring is provided between the connecting pipe and the movable sleeve; the third spring is arranged between the positioning plate and the inner bushing. Through the design of the above structure, when the connecting pipe is pressed down, the seventh rack will firmly press the eighth rack on the docking sleeve. At this time, the transmission of the connecting pipe, the movable sleeve, the docking sleeve, the rotating sleeve, and the push rod is realized. The downward movement of the push rod is driven by the rotation of the rotating sleeve for the liquid medicine injection operation.

[0010] Preferably, the push rod check mechanism includes a locking sleeve that is limited and engaged with the bottom surface of the push rod. A ninth rack is fixed on the surface of the locking sleeve. A check sleeve is provided at the upper end of the locking sleeve. A tenth rack is fixed to the bottom of the check sleeve. The tenth rack and the ninth rack are meshed with each other. A fourth spring is provided between the check sleeve and the locking sleeve. A second annular sawtooth is provided inside the check sleeve. The second annular sawtooth is limited and engaged with a second spring strip. The second spring strip is fixed on the receiving sleeve. The receiving sleeve is limited and engaged with the surface of the push rod. Through the design of the locking sleeve, the fourth spring, the check sleeve, the receiving sleeve, the second spring strip and the second annular sawtooth, the push rod can only move downward and cannot retract. When it is necessary to push the push rod back, at this time, the locking sleeve lacks the abutment of the cartridge bottle and will be disengaged from the check sleeve under the restoring force of the fourth spring. At this time, when pushing the push rod back, it will drive the receiving sleeve and the check sleeve to rotate synchronously, realizing the reset of the push rod.

[0011] Preferably, a limiting cavity is provided inside the bottom of the connecting rod. A limiting ring is threadedly connected in the limiting cavity. The limiting ring is limited and engaged with the surface of the push rod. The distance that the limiting ring moves in the limiting cavity is the same as the distance that the push rod moves when injecting the liquid medicine. Through the design of the limiting cavity and the limiting ring, when the device performs dose adjustment and energy storage by applying force, the limiting ring moves upward synchronously. On the contrary, when the device releases the stored energy, the connecting pipe, the movable sleeve, the docking sleeve and the rotating sleeve will all rotate synchronously, thereby driving the push rod to move downward. At the same time, the rotation of the connecting pipe will also drive the connecting rod to rotate. When the connecting pipe and the connecting rod rotate in the opposite direction, the limiting ring will move downward, and the spiral scale will return to its original position, and the downward movement of the push rod will realize the injection operation of the liquid medicine.

[0012] Preferably, the bottom of the upper pen shell is in interference fit with a cartridge case. The cartridge case is threadedly connected with the lower pen shell. The rotating sleeve is arranged at the middle position of the cartridge case. The bottom end of the docking sleeve is attached to the top surface of the cartridge case. The locking sleeve is limited and engaged inside the cartridge case. By designing the upper pen shell to be split, it is convenient for assembly.

[0013] Preferably, a limiting piece is in interference fit on the cartridge case. The limiting piece is located below the locking sleeve. Through the design of the limiting piece, it is convenient to limit the locking sleeve and prevent the locking sleeve from popping out and falling off under the restoring force of the fourth spring when the cartridge bottle is taken out.

[0014] Compared with the prior art, the beneficial effects of the present invention are: The present invention is designed with a knob, an inner bushing, a first rack, an outer bushing, a second rack, an insertion block, a slot, a first spring strip, a first annular sawtooth, a connecting rod, a spiral scale disk that is limited and engaged on the surface of the connecting pipe, the spiral scale disk is threadedly connected to the inner wall of the upper pen shell, a torsion spring clamped inside the connecting pipe, a movable sleeve, a third rack, a docking sleeve, a fourth rack, a seventh rack, an eighth rack, a rotating sleeve, a sixth rack, a first spring, a second spring and a third spring; when injecting liquid medicine is required, first rotate the knob to drive the outer bushing and the inner bushing to rotate synchronously. The rotation of the inner bushing drives the connecting rod to rotate, and the rotation of the connecting rod drives the connecting pipe to rotate. When the connecting pipe rotates, it drives the torsion spring to rotate for energy storage operation; Meanwhile, when the connecting pipe rotates, under the action of the spiral scale disk being limited and engaged with the connecting pipe and the spiral scale disk being threadedly connected to the inner wall of the upper pen shell, the spiral scale disk rotates and moves downward at the same time, realizing the dose adjustment operation; When the connecting pipe rotates, it drives the movable sleeve to rotate. The movable sleeve meshes with the docking sleeve and the docking sleeve does not move. At this time, with the cooperation of the third spring, the movable sleeve can perform skip tooth movement on the docking sleeve to ensure the normal rotation of the connecting pipe, that is, to ensure that the dose adjustment operation and the energy storage operation can proceed normally; At this time, due to the one-way limiting effect of the first spring strip and the first annular sawtooth, after the energy storage and dose adjustment operations are completed, they are limited and stuck to prevent reset; After the dose adjustment operation and the energy storage operation are completed, press the button to simultaneously squeeze the connecting rod, the connecting pipe and the inner bushing downward. The downward movement of the connecting rod and the connecting pipe drives the seventh rack to move downward until it abuts and meshes with the eighth rack on the docking sleeve; the downward movement of the inner bushing compresses the first spring. At this time, the inner bushing and the outer bushing are disengaged from meshing, that is, the limitation on the connecting rod and the connecting pipe is released. At this time, under the restoring force of the torsion spring, it will rotate in the reverse direction, driving the connecting pipe, the movable sleeve and the docking sleeve to rotate. The rotation of the docking sleeve drives the rotating sleeve to rotate, and the rotation of the rotating sleeve drives the push rod to move downward to realize the injection of liquid medicine; at the same time, the spiral scale disk will rotate and move upward to return to its original position; During the above-mentioned energy storage and liquid medicine injection processes, the limiting ring in the limiting cavity at the bottom of the connecting rod will perform upward and downward movements synchronously. Through the design of the length of the limiting cavity, further limiting control of the dose adjustment and the injection volume is realized, so that each dose adjustment value and each injection volume are strictly controlled, further making it simpler and more convenient for patients to operate and reducing misoperation; Through the design of the locking sleeve, the ninth rack, the check sleeve, the tenth rack, the second annular sawtooth, the fourth spring, the receiving sleeve and the second spring strip, when injecting the liquid medicine, the cartridge vial abuts against the locking sleeve, and the fourth spring is in a compressed state. Under the meshing of the ninth rack and the tenth rack, the locking sleeve tightly meshes with the check sleeve. At this time, the locking sleeve that is limited and engaged with the cartridge case and the check sleeve that meshes with the locking sleeve are stationary. However, under the limitation of the second annular sawtooth and the second spring strip, the receiving sleeve can only rotate in a single direction, that is, the push rod can only move downward to inject the liquid medicine and cannot retract reversely. Therefore, the push rod will always tightly abut against the piston of the cartridge vial. When the liquid medicine in the cartridge vial is injected and the push rod needs to be reset, by pushing the push rod upward, since the locking sleeve lacks the abutment of the cartridge vial at this time, the locking sleeve and the check sleeve will be disengaged under the restoring force of the fourth spring. Therefore, when pushing the push rod upward, the check sleeve and the receiving sleeve will be driven to rotate together, thereby ensuring that the push rod can be reset smoothly. In summary, it can be seen that after each injection of the present invention, the push rod remains in place and tightly abuts against the piston in the cartridge vial. The next time an injection is made, only the dose needs to be adjusted, and there is no need for an emptying operation, realizing automatic multiple injection adjustments. At the same time, in the present invention, the dose adjustment operation and the energizing and energy storage operation are carried out synchronously, and after the liquid medicine injection is completed, it will return to the original position, providing convenience for the next injection and making the entire injection operation simpler and more convenient. At the same time, it can also ensure that each dose adjustment value and each injection volume are strictly controlled to avoid misoperation. At the same time, it can achieve simple and accurate reset of the push rod. Finally, through the interference fit design of the upper pen case and the cartridge case, the entire device can achieve better assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a front view structural schematic diagram of the present invention; Figure 2 It is an exploded structural schematic diagram of the present invention; Figure 3 It is a three-dimensional structural schematic diagram of the upper pen case of the present invention; Figure 4 It is a three-dimensional structural schematic diagram of the cartridge case of the present invention; Figure 5 It is a bottom view structural schematic diagram of the cartridge case of the present invention; Figure 6 It is a bottom view structural schematic diagram of the knob of the present invention; Figure 7 It is a top view structural schematic diagram of the outer bushing of the present invention; Figure 8 It is a bottom view structural schematic diagram of the outer bushing of the present invention; Figure 9 It is a three-dimensional structural schematic diagram of the connection state of the connecting rod and the inner bushing of the present invention; Figure 10 Schematic three-dimensional structure diagram of the limit ring in the present invention; Figure 11 Schematic three-dimensional structure diagram of the connecting rod in the present invention; Figure 12 Schematic bottom view of the structure of the connecting pipe in the present invention; Figure 13 Schematic three-dimensional structure diagram of the connecting pipe in the present invention; Figure 14 Schematic three-dimensional structure diagram of the movable sleeve in the present invention; Figure 15 Schematic top view of the structure of the movable sleeve in the present invention; Figure 16 Schematic three-dimensional structure diagram of the docking sleeve in the present invention; Figure 17 Schematic three-dimensional structure diagram of the rotating sleeve in the present invention; Figure 18 Schematic three-dimensional structure diagram of the locking sleeve in the present invention; Figure 19 Schematic three-dimensional structure diagram of the check sleeve and the fourth spring in the present invention; Figure 20 Schematic top view of the structure of the connection state between the check sleeve and the receiving sleeve in the present invention.

[0016] Labels in the figure: 110, upper pen case; 111, first annular sawtooth; 112, positioning plate; 113, observation port; 120, cartridge case; 121, limiting piece; 130, lower pen case; 140, knob; 141, insertion block; 150, button; 160, pen cap; 210, push rod; 310, connecting rod; 311, limiting cavity; 410, inner lining sleeve; 411, first rack; 420, outer lining sleeve; 421, second rack; 422, slot; 423, first spring strip; 430, first spring; 510, connecting pipe; 511, seventh rack; 610, movable sleeve; 611, third rack; 612, opening; 620, docking sleeve; 621, fourth rack; 622, fifth rack; 623, eighth rack; 630, rotating sleeve; 631, sixth rack; 640, second spring; 650, third spring; 710, spiral scale; 810, torsion spring; 910, locking sleeve; 911, ninth rack; 920, check sleeve; 921, tenth rack; 922, second annular sawtooth; 930, fourth spring; 940, receiving sleeve; 941, second spring strip. Detailed implementation manners

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention.

[0018] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely represents some embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0019] It should be noted that, without conflict, the embodiments in the present invention and the features and technical solutions in the embodiments may be combined with each other.

[0020] It should be noted that like reference numerals and letters denote like items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0021] The embodiments of the present invention are as follows: See Figure 1-20 As shown, an auto-injector pen includes a pen housing; the pen housing includes an upper pen housing 110 and a lower pen housing 130; a pen cap 160 is threadedly connected to the surface of the lower pen housing 130; a cartridge is snap-fitted inside the lower pen housing 130. There is a piston inside the cartridge. The top of the piston inside the cartridge abuts against a push rod 210, and the push rod 210 extends into the upper pen housing 110; a knob 140 is movably snap-fitted to the top of the upper pen housing 110. A button 150 is snap-fitted to the top of the knob 140. The button 150 abuts against a connecting rod 310, and the connecting rod 310 is snap-fitted on the outer surface of the push rod 210; Dose adjustment and force storage structure: See attached Figure 3 and attached Figure 5 and attached Figure 6 and attached Figure 7 and attached Figure 8 and attached Figure 9: A limiting sleeve is sleeved on the top surface of the connecting rod 310, and a first rack 411 is fixed on the inner lining sleeve 410. An outer lining sleeve 420 is sleeved on the surface of the inner lining sleeve 410, and a second rack 421 is fixed inside the outer lining sleeve 420. The second rack 421 and the first rack 411 are meshed with each other; two groups of slots 422 are opened at the top of the outer lining sleeve 420, and two groups of insertion blocks 141 are fixed inside the knob 140. The insertion blocks 141 and the slots 422 are matched with each other; two groups of first spring strips 423 are fixed on the outer lining sleeve 420, and a first annular sawtooth 111 is fixed on the inner wall of the upper pen shell 110. The first spring strips 423 extend in an arc from the inner side to the outer side of the slots 422 and are clamped with the first annular sawtooth 111 in a limiting manner; the two groups of first spring strips 423 and the two groups of insertion blocks 422 are both arranged in central symmetry; See appendix Figure 2 and appendix Figure 11 and appendix Figure 12 and appendix Figure 13 : An adapter tube 510 is sleeved on the outer surface of the connecting rod 310, and at the same time, the bottom of the connecting rod 310 is clamped with the adapter tube 510 in a limiting manner; a torsion spring 810 is arranged between the connecting rod 310 and the adapter tube 510. The bottom of the torsion spring 810 is clamped with the bottom of the adapter tube 510, and the top of the torsion spring 810 is clamped with the positioning plate 112; a plurality of vertical slots are opened on the surface of the adapter tube 510, and the spiral scale 710 is clamped on the surface of the adapter tube 510 in a limiting manner. At the same time, the spiral scale 710 is threadedly connected with the inner wall of the upper pen shell 110, and an observation port 113 matched with the spiral scale 710 is opened on the upper pen shell 110; In this way, by rotating the knob 140, under the cooperation of the insertion blocks 141 and the slots 422, the outer lining sleeve 420 is driven to rotate. At this time, the first spring strips 423 jump on the first annular sawtooth 111; when the outer lining sleeve 420 rotates, under the meshing action of the second rack 421 and the first rack 411, the inner lining sleeve 410 is driven to rotate, and when the inner lining sleeve 410 rotates, the connecting rod 310 is driven to rotate; when the connecting rod 310 rotates, the adapter tube 510 and the torsion spring 810 will be driven to rotate, and at the same time, the spiral scale 710 will spiral down to realize the adjustment of the dose; and when the torsion spring 810 rotates, it will realize the winding and energy storage, and under the limitation of the first spring strips 423 and the first annular sawtooth 111, the adapter tube 510, the torsion spring 810 and the spiral scale 710 are maintained in the adjusted state unchanged; See appendix Figure 2 and appendix Figure 14 and appendix Figure 15 and appendix Figure 16 and appendix Figure 17: A rotating sleeve 630 is clamped at the central position of the bottom of the upper pen shell 110. At the same time, the rotating sleeve 630 is threadedly connected to the push rod 210. A sixth rack 631 is fixed on the surface of the rotating sleeve 630. A docking sleeve 620 is sleeved on the outer surface of the rotating sleeve 630. The bottom of the docking sleeve 620 fits against the inner bottom end of the upper pen shell 110. A fifth rack 622 is fixed inside the docking sleeve 620. The fifth rack 622 meshes with the sixth rack 631; A fourth rack 621 is fixed at the top of the docking sleeve 620. An activity sleeve 610 is arranged at the top of the docking sleeve 620. A third rack 611 is fixed at the bottom of the activity sleeve 610. The third rack 611 and the fourth rack 621 mesh with each other; The activity sleeve 611 is clamped at the bottom of the connecting pipe 510. A third spring 650 is arranged on the outer surface of the docking sleeve 620. The bottom of the third spring 650 fits against the inner bottom end of the upper pen shell 110. The top of the third spring 650 fits against and abuts against the bottom of the connecting pipe 510; During the above dose adjustment process, the connecting pipe 510 is driven to rotate, which drives the clamped activity sleeve 610 to rotate. Due to the action of the third spring 650, at this time, under the action of the rotating sleeve 630 that is limited from moving by the push rod 210 and the docking sleeve 620 that is limited from moving by the rotating sleeve 630, the activity sleeve 610 will perform a skip tooth rotation on the surface of the docking sleeve 620, so as to ensure the rotation of the connecting pipe 510 and complete the dose adjustment and energization energy storage operations; Liquid medicine injection structure: See attached Figure 2 、attached Figure 13 、attached Figure 14 、attached Figure 15 、attached Figure 16 and attached Figure 17 : A first spring 430 is abutted between the positioning plate 112 and the inner lining sleeve 410. A seventh rack 511 is fixed at the bottom of the connecting pipe 510. The seventh rack 511 is inserted into the activity sleeve 610 together with the connecting pipe 510. An opening 612 matching the seventh rack 511 is formed on the activity sleeve 610. A second spring 640 is arranged between the activity sleeve 610 and the connecting pipe 510. The top of the second spring 640 abuts against the connecting pipe 510. The bottom of the second spring 640 abuts against the activity sleeve 610; An eighth rack 623 is fixed inside the top of the docking sleeve 620. The eighth rack 623 and the seventh rack 511 cooperate with each other; Referring to the foregoing, when the liquid medicine needs to be injected, by pressing the button 150, the connecting rod 310 will be driven to move downward at this time. The downward movement of the connecting rod 310 will drive the inner lining sleeve 410, the connecting pipe 510 and the seventh rack 511 to move downward together. At this time, the first spring 430 and the second spring 640 are compressed, and the inner lining sleeve 410 is disengaged from the outer lining sleeve 420, and the seventh rack 511 is butted and engaged with the eighth rack 623. Therefore, when the inner lining sleeve 410 is disengaged from the outer lining sleeve 420, the limit of the outer lining sleeve 420 on the inner lining sleeve 410 will be released, so that the torsion spring 810 that stores energy by winding will drive the connecting pipe 510 to rotate in the reverse direction under the action of the restoring force, and at the same time drive the spiral scale 710 to gradually return to its original position; at the same time, when the seventh rack 511 is butted and engaged with the eighth rack 623, it will cause the connecting pipe 510 to rotate and drive the movable sleeve 610 and the docking sleeve 620 to rotate synchronously. The rotation of the docking sleeve 620 will drive the rotating sleeve 630 to rotate, and the rotation of the rotating sleeve 630 will drive the push rod 210 to rotate. Since the push rod 210 is limited and cannot rotate, the push rod 210 will move downward and gradually push the piston in the cartridge bottle to inject the liquid medicine until the injection of the adjusted dose is completed; Dose adjustment limit structure: See appendix Figure 2 , appendix Figure 10 and appendix Figure 11 : A limit cavity 311 is provided inside the bottom end of the connecting rod 310, and a limit ring 320 is threadedly connected inside the limit cavity 311. The limit ring 320 is limit-connected to the outer surface of the push rod 210; in the above dose adjustment and energy storage operation by winding, when the connecting rod 310 rotates, the limit ring 320 will rise synchronously inside the limit cavity 311 until it is limited by the top of the limit cavity 311 to complete the dose adjustment; on the contrary, when performing the injection operation, the limit ring 320 will move downward inside the limit cavity 311 until it is limited by the bottom of the limit cavity 311; through the design of the length of the limit cavity 311, further limit control of the dose adjustment and the injection volume is realized, so that each dose adjustment value and each injection volume are strictly controlled, further making the operation of the patient simpler and more convenient and reducing misoperation; Push rod 210 check valve and reset structure: See appendix Figure 2 , appendix Figure 4 , appendix Figure 18 , appendix Figure 19 and appendix Figure 20: At the bottom of the upper pen shell 110, a locking sleeve 910 that fits tightly against the top of the cartridge bottle is snap-fitted. At the top of the locking sleeve 910, a ninth rack 911 is fixed. At the upper part of the locking sleeve 910, a check sleeve 920 is provided. At the bottom of the check sleeve 920, a tenth rack 921 is fixed. The tenth rack 921 meshes with the ninth rack 911; between the check sleeve 920 and the locking sleeve 910, a fourth spring 930 in a compressed state is provided. Inside the top of the check sleeve 920, a receiving sleeve 940 is provided. The receiving sleeve 940 is threadedly connected to the push rod 210; on the surface of the receiving sleeve 940, a second spring strip 941 is fixed. On the inner wall of the check sleeve 920, a second annular sawtooth 922 that is snap-fitted and limited with the second spring strip 941 is fixed; During the injection process, since the locking sleeve 910 is snap-fitted and limited with the upper pen shell 110, the locking sleeve 910 cannot rotate. At the same time, the cartridge bottle abuts against the locking sleeve 910. At this time, the fourth spring 930 is in a compressed state. The locking sleeve 910 and the check sleeve 920 mesh with each other. Therefore, when the push rod 210 moves downward, it will drive the receiving sleeve 940 to rotate. At this time, the second spring strip 941 on the receiving sleeve 940 bounces on the second annular sawtooth 922; when the injection is completed, since the locking sleeve 910 cannot rotate, the check sleeve 920 meshing with it cannot rotate either; the check sleeve 920 cannot rotate. Limited by the second annular sawtooth 922 and the second spring strip 941, the receiving sleeve 940 cannot rotate either. Therefore, the push rod 210 is limited and cannot move, realizing the check of the push rod 210; When reinstalling and needing to push the push rod 210 back to its original position, since there is no abutment of the cartridge bottle at this time, the locking sleeve 910 and the check sleeve 920 will disengage from meshing under the restoring force of the fourth spring 930. Therefore, when the push rod 210 is pushed upward, it will drive the receiving sleeve 940 to rotate at this time. When the receiving sleeve 940 rotates, it will drive the check sleeve 920 to rotate synchronously under the action of the second spring strip 941 and the second annular sawtooth 922 until the push rod 210 returns to its original position, realizing the reset operation of the push rod 210; See Appendix Figure 1 、Appendix Figure 2 、Appendix Figure 4 and Appendix Figure 5 : The bottom of the upper pen shell 110 is in interference fit with a cartridge case 120. A rotating sleeve 630 is clamped at the central position of the cartridge case 120. A docking sleeve 620 is attached to the upper surface of the cartridge case 120; the locking sleeve 910 is snap-fitted and limited inside the bottom end of the cartridge case 120. The check sleeve 920 and the receiving sleeve 940 are synchronously arranged in the cartridge case 120. The lower pen shell 130 is threadedly connected to the cartridge case 120; at the upper end of the cartridge case 120, a limiting piece 121 is in interference fit; the limiting piece 121 is located below the locking sleeve 910 and is used to prevent the locking sleeve 910 from falling off; the upper pen shell 110 is designed to be split for convenient assembly.

[0022] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by terms such as "upper" and "lower" is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship commonly understood by those skilled in the art. Such terms are only used 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 should not be construed as a limitation on the present invention. In addition, terms such as "first" and "second" are only used for descriptive distinction and should not be construed as indicating or implying relative importance.

[0023] The above embodiments are only used to illustrate the present invention and do not limit the technical solutions described in the present invention. Although the present specification has described the present invention in detail with reference to the above respective embodiments, the present invention is not limited to the above specific embodiments. Therefore, any modification or equivalent replacement of the present invention; and all technical solutions and their improvements that do not depart from the spirit and scope of the invention are covered by the scope of the claims of the present invention.

Claims

1. An auto-injector pen, characterized in that, Comprising: A pen shell, including an upper pen shell (110) and a lower pen shell (130) connected to each other; a knob (140) is rotatably connected to the end of the upper pen shell (110), and a button (150) is snap-fitted to the end of the knob (140); A pen cap (160) sleeved on the surface of the end of the lower pen shell (130); An injection mechanism, including a cartridge installed inside the lower pen shell (130) and a push rod (210) installed inside the upper pen shell (110), the bottom of the push rod (210) abuts against the cartridge, a connecting rod (310) is sleeved on the outer surface of the push rod (210) with a limit, and the top of the connecting rod (310) is snap-fitted with the button (150); A dose adjustment mechanism, including an adapter tube (510) provided on the outer surface of the connecting rod (310), the bottom of the connecting rod (310) is clamped at the bottom of the adapter tube (510), a spiral scale disk (710) is snap-fitted on the outer surface of the adapter tube (510), the spiral scale disk (710) is threadedly connected inside the upper pen shell (110), and an observation port (113) matching the spiral scale disk (710) is provided on the upper pen shell (110); an upper transmission component is provided between the inside of the knob (140) and the connecting rod (310), and a lower transmission component is provided between the bottom of the adapter tube (510) and the push rod (210); An energy storage mechanism, including a torsion spring (810) provided between the connecting rod (310) and the adapter tube (510), the bottom of the torsion spring (810) is clamped with the adapter tube (510), the top of the torsion spring (810) is clamped on a positioning plate (112), and the positioning plate (112) is fixed inside the upper pen shell (110); A clutch mechanism, including a switch member provided between the adapter tube (510) and the lower transmission component, a second spring (640) is provided between the switch member and the adapter tube (510), and a first spring (430) is provided between the button (150) and the positioning plate (112); and A push rod check mechanism.

2. The auto-injector pen according to claim 1, wherein The upper transmission component includes a lining sleeve (410) snap-fitted on the surface of the connecting rod (310), a first rack (411) is provided on the lining sleeve (410), an outer lining sleeve (420) is sleeved on the surface of the lining sleeve (410), a second rack (421) is provided on the outer lining sleeve (420), and the first rack (411) and the second rack (421) are meshed with each other; the outer lining sleeve (420) is clamped with the inner wall of the knob (140).

3. The auto-injector pen according to claim 2, wherein, The surface of the outer bushing (420) is provided with two groups of arc-shaped slots (422) that are centrosymmetric. Inside the knob (140), two groups of arc-shaped inserts (141) are symmetrically arranged, and the inserts (141) cooperate with the slots (422); a first spring strip (423) is fixed on each group of the slots (422), and the two first spring strips (423) are designed to be centrosymmetric. A first annular sawtooth (111) that is in limit abutment with the tail of the first spring strip (423) is fixed on the inner wall of the upper pen shell (110).

4. The auto-injector pen according to claim 3, wherein, The lower transmission assembly includes a movable sleeve (610) that is limit-fitted at the bottom of the connection pipe (510). A third rack (611) is fixed at the bottom of the movable sleeve (610); the bottom of the movable sleeve (610) abuts against a docking sleeve (620). A fourth rack (621) is fixed at the top of the docking sleeve (620), and the third rack (611) and the fourth rack (621) mesh with each other. A third spring (650) is provided between the docking sleeve (620) and the connection pipe (510); a fifth rack (622) is provided inside the docking sleeve (620). A rotating sleeve (630) is threadedly connected to the surface of the push rod (210), and a sixth rack (631) is fixed on the surface of the rotating sleeve (630). The fifth rack (622) and the sixth rack (631) mesh with each other; the rotating sleeve (630) is clamped at the inner bottom end of the upper pen shell (110).

5. The auto-injector pen according to claim 4, characterized in that, The switch member includes a seventh rack (511) fixed at the bottom of the connection pipe (510). An opening (612) that cooperates with the seventh rack (511) is provided on the movable sleeve (610). An eighth rack (623) is fixed on the inner side of the top of the docking sleeve (620), and the seventh rack (511) and the eighth rack (623) mesh with each other; the second spring (640) is provided between the connection pipe (510) and the movable sleeve (610); the third spring (650) is arranged between the positioning plate (112) and the inner lining sleeve (410).

6. The auto-injector pen according to claim 5, wherein The push rod anti-backflow mechanism includes a locking sleeve (910) that is limit-fitted on the bottom surface of the push rod (210). A ninth rack (911) is fixed on the surface of the locking sleeve (910). A backflow prevention sleeve (920) is provided at the upper end of the locking sleeve (910). A tenth rack (921) is fixed at the bottom of the backflow prevention sleeve (920), and the tenth rack (921) and the ninth rack (911) mesh with each other; a fourth spring (930) is provided between the backflow prevention sleeve (920) and the locking sleeve (910); a second annular sawtooth (922) is provided inside the backflow prevention sleeve (920), and the second annular sawtooth (922) is in limit engagement with a second spring strip (941). The second spring strip (941) is fixed on a receiving sleeve (940), and the receiving sleeve (940) is threadedly connected to the surface of the push rod (210).

7. The auto-injector pen according to claim 6, wherein, A limiting cavity (311) is provided inside the bottom of the connecting rod (310), a limiting ring (320) is threadedly connected in the limiting cavity (311), and the limiting ring (320) is limited and engaged on the surface of the push rod (210).

8. The auto-injector pen according to claim 7, wherein, The moving distance of the limiting ring (320) in the limiting cavity (311) is the same as the moving distance of the push rod (210) when injecting the liquid medicine.

9. The auto-injector pen according to claim 8, wherein, An interference fit is provided between the bottom of the upper pen shell (110) and a clamping shell (120), and the clamping shell (120) is threadedly connected to the lower pen shell (130); the rotating sleeve (630) is clamped at the middle position of the clamping shell (120); the bottom end of the docking sleeve (620) is attached to the top surface of the clamping shell (120); the locking sleeve (910) is limited and engaged in the clamping shell (120).

10. The auto-injector pen according to claim 8, characterized in that, A limiting piece (121) is provided on the clamping shell (120) with an interference fit, and the limiting piece (121) is located below the locking sleeve (910).

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