Single-use pre-filled auto-injector

Abstract

The application discloses a disposable pre-filled automatic injection pen and relates to the technical field of injection pens, which comprises a pre-filled assembly and an automatic injection assembly. The pre-filled assembly comprises a pen shell and a pen cap which are connected through clamping. A medicine bottle is arranged in the lower section of the pen shell. The automatic injection assembly comprises an outer locking cylinder which is movably arranged in the pen shell. The outer locking cylinder is elastically sleeved outside an inner locking cylinder. An injection cylinder is slidably connected in the inner locking cylinder. The bottom of the injection cylinder is abuttingly connected with an inner piston of the medicine bottle. The injection cylinder is elastically connected with a pen cover. The pen cover is clamped on the top of the pen shell. Upper and lower clamping grooves are respectively arranged on the upper and lower ends of the outer surface of the injection cylinder. A first elastic limiting part is arranged on the inner locking cylinder. The first elastic limiting part is respectively matched with the upper and lower clamping grooves. The automatic injection can be realized by pressing the driving cylinder after it is contacted with the skin of a patient. The structure is simple, the operation is convenient, and time and labor are saved.

Description

Technical Field

[0001] This invention relates to the field of injection pen technology, and more specifically to a disposable pre-filled automatic injection pen. Background Technology

[0002] With the rapid development of biopharmaceutical technology, the clinical application of insulin, monoclonal antibodies, peptide drugs, vaccines, and various chronic disease treatments is becoming increasingly widespread. These drugs often require subcutaneous injection, and some require long-term home self-injection by patients. Therefore, extremely high demands are placed on the ease of operation, safety, and user experience of the drug delivery device. Pre-filled syringes, due to their advantages such as pre-filled medication, elimination of the need for on-the-spot preparation, and avoidance of cross-infection, have become the mainstream drug delivery carrier for biological agents. Furthermore, the automatic injection pen, which is paired with the pre-filled syringe, provides stable injection power through a built-in spring, eliminating the need for manual injection and significantly reducing the difficulty of operation and injection pain for patients, making it a core device for home injection drug delivery.

[0003] Currently, existing disposable pre-filled automatic injection pens on the market can achieve basic automatic injection functions. For example, the Chinese authorized utility model patent CN211410495U, with an application date of December 9, 2019, an announcement date of September 4, 2020, discloses a disposable automatic injection pen with an automatic needle withdrawal function. This pen includes a button and a pen body. The button has injection opening safety and injection activation functions. The pen body internally houses a push spring, an injection push rod with a needle withdrawal trigger, a pre-filled syringe holder with a needle, and a needle withdrawal spring. A pen cap is located at the bottom of the pen body. After the cap is removed, the injection pen is rotated to open, and pressing the button activates the push spring lock plate, causing the push spring lock to open. The push rod, under pressure, pushes the piston in the vial, initiating automatic injection. Although this achieves automatic injection, its structure is complex and inconvenient to operate. Therefore, there is an urgent need to provide a disposable pre-filled automatic injection pen to solve the aforementioned technical problems. Summary of the Invention

[0004] The purpose of this invention is to design a disposable pre-filled automatic injection pen to solve the problems mentioned in the background art, such as the complex automatic injection function structure and inconvenient operation of existing disposable automatic injection pens.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution: A disposable pre-filled automatic injection pen includes a pre-filling assembly and an automatic injection assembly. The pre-filling assembly includes a pen shell and a pen cap that are snap-fitted together, with a medicine bottle located in the lower part of the pen shell. The automatic injection assembly includes an outer locking cylinder movably disposed inside the pen shell, which is elastically fitted outside an inner locking cylinder. An injection cylinder is slidably connected inside the inner locking cylinder, and the bottom of the injection cylinder abuts against a piston inside the medicine bottle. The injection cylinder is elastically connected to the pen cap, which is snapped onto the top of the pen shell. The upper and lower ends of the outer surface of the injection cylinder are respectively provided with... The device includes an upper and lower locking slot. The inner locking cylinder has a first elastic limiting part that engages with the upper and lower locking slots respectively. The outer surface of the first elastic limiting part has an outward protrusion that fits tightly against the inner wall of the outer locking cylinder. A driving cylinder slides between the pen shell and the medicine bottle, with its bottom extending outside the pen shell and its top abutting against the bottom of the outer locking cylinder. This application achieves automatic injection by pressing firmly after the driving cylinder contacts the patient's skin. The structure is simple, the operation is convenient, and it saves time and effort.

[0006] Preferably, a pen cap plug is integrally provided at the bottom of the pen shell, and the pen cap is inserted into the outer surface of the pen cap plug to facilitate the assembly and disassembly of the pen cap and the pen shell; a pen cap slot is provided on the pen shell, and a pen shell locking block is fixed on the pen cap, and the pen shell locking block engages with the pen cap slot to facilitate the installation of the pen cap; an observation window is provided on the surface of the pen shell to facilitate the patient's observation of the injection.

[0007] Preferably, a cartridge positioning ring is fixed to the lower end of the pen casing, and cartridge positioning blocks are symmetrically fixed to both sides of the upper surface of the cartridge positioning ring. The observation window passes through the pen casing and the cartridge positioning blocks respectively to realize the observation of drug injection. A cartridge is inserted between the two sets of cartridge positioning blocks. A top protrusion is fixed to the upper end of the cartridge, and the top protrusion fits against the top surface of the cartridge positioning block. Cartridge claws are symmetrically fixed to the bottom of the cartridge. Cartridge limiting grooves that engage with the cartridge claws are symmetrically opened at the bottom of the cartridge positioning ring, so that the cartridge can be easily inserted into the pen casing and limited in place, which facilitates subsequent injection operations. Limiting ridges that match the width of the cartridge positioning blocks are symmetrically fixed to both the upper and lower ends of the cartridge, so that the cartridge can be oriented to be inserted into the pen casing and the cartridge can be limited in the vertical and circumferential directions, so that the cartridge is stably placed in the pen casing. The medicine bottle is secured inside the medicine cartridge. Symmetrically fixed medicine bottle claws are located at the bottom of the medicine cartridge, and these claws fit snugly against the bottom of the medicine bottle. The distance between the two sets of medicine bottle claws is smaller than the outer diameter of the medicine bottle, preventing the medicine bottle from moving downwards. A needle sleeve in the shape of an inverted frustum is sealed to the needle tip of the medicine bottle. An elastic claw is integrally connected inside the pen cap, and the top of the elastic claw is set as an arc-shaped protrusion with the same shape as the needle sleeve. The elastic claw engages with the upper surface of the needle sleeve, so that when the pen cap is installed with the pen shell, the elastic claw hooks the needle sleeve. When in use, the user can remove the needle sleeve at the same time as removing the pen cap, making the operation simple, convenient, time-saving, and labor-saving.

[0008] Preferably, a first spring in a compressed state is connected between the outer locking cylinder and the inner locking cylinder. In this state, the first spring is compressed by the outer and inner locking cylinders, possessing elastic potential energy. Under the restoring force generated by this elastic potential energy, it pushes the outer and inner locking cylinders outward. A syringe slot is provided in the middle of the pen cap's interior. A positioning rod is fitted inside the syringe slot and inserted into the syringe. A second spring in a compressed state is located between the positioning rod and the syringe. The uncompressed length of the second spring is greater than the axial length of the syringe. The top of the second spring abuts against the positioning rod, and the bottom of the second spring abuts against the bottom surface of the syringe's interior. Under the action of the pen cap, the positioning rod, and the syringe, the second spring is tightly compressed within the syringe. The two springs also possess elastic potential energy, and under the restoring force generated by this elastic potential energy, they will also act in the opposite direction on the syringe and the positioning rod. The bottom of the inner locking cylinder is provided with an elastic pressure plate, which abuts against the top surface of the vial, limiting the vial's position and preventing rigid contact and compression between the vial and the inner locking cylinder while keeping the vial stationary. The bottom of the drive cylinder has an integrally formed pressure surface, and the vial needle is located inside this pressure surface, forming a hidden needle structure so that the patient cannot see the needle during injection, reducing their anxiety. A connecting piece is symmetrically fixed to the top of the drive cylinder, and a limiting opening is provided on the connecting piece. Drive cylinder spring pieces are symmetrically fixed to both sides of the vial, and a locking protrusion is fixed to the top of the side wall of each drive cylinder spring piece. This locking protrusion engages with the limiting opening, allowing the drive cylinder to move along the limiting opening.

[0009] Preferably, the bottom surface of the outer locking cylinder is symmetrically fixed with first spring positioning protrusions on both sides. The first spring is engaged between the outer locking cylinder and the first spring positioning protrusions. The outer wall of the outer locking cylinder is fixed with a lower limiting protrusion, and the outer wall of the inner locking cylinder is fixed with an upper limiting protrusion. The outer walls of the lower limiting protrusion and the upper limiting protrusion are both in contact with the inner sidewall of the first spring to limit the first spring and prevent the first spring from being misaligned and affecting the injection.

[0010] Preferably, the inner locking cylinder is fitted with a limiting cylinder inside, and a second elastic limiting part that cooperates with the limiting cylinder is fixed on the inner locking cylinder. The limiting cylinder has a retaining groove inside, and a retaining lug that cooperates with the retaining groove is fixed on the top of the injection cylinder, so that the injection cylinder can only move in the vertical direction, thereby limiting the movement of the injection cylinder.

[0011] Preferably, the inner wall of the pen casing is symmetrically provided with directional grooves, and the outer wall of the bottom end of the outer locking cylinder is symmetrically fixed with an outer locking cylinder directional block that cooperates with the directional groove. The outward protrusion and the second elastic limiting part are both arranged on the same side as the outer locking cylinder directional block. The pen cap directional block that cooperates with the directional groove is symmetrically fixed on the side wall of the pen cap. Limiting springs are symmetrically fixed on both sides of the outer locking cylinder. A slider is fixed on the inner wall of the limiting spring. A sliding groove that cooperates with the slider is provided on the outer wall of the bottom of the inner locking cylinder. Through the design of the above structure, the overall assembly process of this application is clear and straightforward.

[0012] Preferably, the top of the inner locking cylinder has symmetrically symmetrically opened slots, and the top of the inner locking cylinder has a sound-emitting tube that can strike the inner surface of the pen cap to produce sound. The side wall of the sound-emitting tube is symmetrically fixed with an extension block that cooperates with the slot. The opening direction of the slot and the extension block is the same as the direction of the outer locking cylinder directional block. The side wall of the sound-emitting tube is symmetrically fixed with an inner locking cylinder locking block, and the upper side wall of the inner locking cylinder has symmetrically opened with a sound-emitting tube locking groove that cooperates with the inner locking cylinder locking block. The inner wall of the sound-emitting tube is tightly fitted with the outer wall of the limiting cylinder. The bottom of the extension block has a buckle groove that is locked onto the upper surface of the first spring. After the injection is completed, the limiting cylinder will move to the lower section inside the inner locking cylinder, disengaging from the squeezing and limiting of the inner locking cylinder locking block. This causes the inner locking cylinder locking block to retract inward under the elastic force of the first spring, thereby disengaging from the sound-emitting tube locking groove. At this time, the sound-emitting tube will strike the inner surface of the pen cap under the restoring force of the first spring, thereby emitting a prompt sound to remind the patient to complete the injection.

[0013] Preferably, the top of the outer locking cylinder is symmetrically provided with a first elastic part, which is configured as an inwardly curved arc. The bottom of the outer side of the second elastic limiting part is fixed with a second elastic part, which is configured as an outwardly curved arc. By setting the first elastic part and the second elastic part, the first elastic part is blocked by the second elastic part, and the outer locking cylinder cannot continue to move towards the pen cap, thus preventing reuse.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention enables automatic injection by pressing the injection pen after the driving cylinder's contact surface contacts the patient's skin, thereby releasing the outer locking cylinder from its limiting lock. Under the action of the second spring, the injection cylinder pushes open the first elastic limiting part, and under the action of the second spring's restoring force, pushes the piston inside the medicine bottle downward, realizing automatic injection operation. It is simple, convenient, time-saving, and labor-saving.

[0015] This invention utilizes the design of a sound-emitting tube slot and an inner locking tube block to facilitate the easy attachment of the sound-emitting tube to the inner locking tube. The design of the limiting tube compresses the inner locking tube block, ensuring it is firmly positioned within the sound-emitting tube slot, thus limiting the sound-emitting tube to its top. The first spring provides thrust to the sound-emitting tube. Upon completion of the injection, the limiting tube moves downward, releasing the compression on the inner locking tube block. At this point, under the restoring force of the first spring, the inner locking tube block disengages from the sound-emitting tube slot and impacts the inner surface of the pen cap, producing a clicking sound to alert the patient that the injection is complete.

[0016] After injection, the second elastic limiting part on the inner locking cylinder is squeezed by the limiting cylinder, thereby causing the second elastic part on the outer side of the second elastic limiting part to open outward, thereby limiting the first elastic part at the upper end of the outer locking cylinder. Even if the pen cap accidentally falls off, it will not trigger a second injection due to slight collision or squeezing of the driving cylinder, thus preventing reuse.

[0017] The present invention, through the design of the directional groove, the outer locking cylinder directional block, the outer protrusion and the second elastic limiting part being arranged on the same side as the outer locking cylinder directional block, and the pen cap directional block, makes the assembly of this application clear and easy to install. Attached Figure Description

[0018] Figure 1 This is a front view structural diagram of the present invention; Figure 2 This is a frontal cross-sectional view of the present invention. Figure 3 This is a front view cross-sectional structural diagram of the pre-filled component in this invention; Figure 4 This is a three-dimensional structural diagram of the pen shell in this invention; Figure 5 This is a top view of the pen casing structure in this invention; Figure 6 This is a schematic diagram of the pen shell structure from below in this invention; Figure 7 This is a three-dimensional structural diagram of the pen cap in this invention; Figure 8 This is a front view schematic diagram of the structure of the medicine tube in this invention; Figure 9 This is a three-dimensional structural diagram of the assembly of the medicine tube and the pen shell in this invention; Figure 10 This is a three-dimensional structural diagram of the drive cylinder in this invention; Figure 11 This is a front view schematic diagram of the injection section in this invention; Figure 12 This is a frontal cross-sectional view of the injection section in this invention; Figure 13 This is a three-dimensional structural diagram of the outer locking cylinder in this invention; Figure 14 This is a top view of the outer locking cylinder in this invention. Figure 15 This is a three-dimensional structural diagram of the inner locking cylinder in this invention; Figure 16 This is a three-dimensional structural diagram of the sound-generating tube in this invention; Figure 17 This is a front view of the structure of the injection cylinder in this invention; Figure 18 This is a three-dimensional structural diagram of the limiting cylinder in this invention; Figure 19 This is a three-dimensional structural diagram of the pen cap in this invention.

[0019] The image shows: 111. Pen casing; 112. Pen cap plug; 113. Pen cap slot; 114. Cartridge positioning ring; 115. Cartridge positioning block; 116. Observation window; 117. Cartridge limiting groove; 118. Orientation groove; Pen cap; 121, flexible locking claw; Pen cap; 131. Pen casing retaining block; 132. Injector cartridge retaining slot; 133. Pen cap directional block; 211. Caliper cartridge; 212. Caliper cartridge claw; 213. Bottle claw; 214. Limiting ridge; 215. Drive cylinder spring; 216. Clamping protrusion; Medicine bottle; 221, needle sheath; 311. Outer locking cylinder; 312. Outer locking cylinder directional block; 313. First spring positioning protrusion; 314. Lower limit protrusion; 315. Limiting spring; 316. Slider; 317. First elastic part; First spring; Inner locking cylinder; 331, slide groove; 332, elastic pressure plate; 333, first elastic limiting part; 334, outward protrusion; 335, second elastic limiting part; 336, second elastic part; 337, upper limit protrusion; 338, slot; 339, sound tube slot; Sound-emitting tube; 341, extension block; 342, inner locking cylinder block; 343, latching groove; Injector; 351, lower slot; 352, upper slot; 353, second spring; 354, positioning rod; 355, retaining lug; Drive cylinder; 361, contact surface; 362, connecting piece; 363, limiting opening; 410. Limiting cylinder; 411. Clamping groove. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0021] Therefore, the following detailed description of embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely illustrates some embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0022] It should be noted that, unless otherwise specified, the embodiments and features and technical solutions in the present invention can be combined with each other.

[0023] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0024] The embodiments of the present invention are as follows: See Figure 1-19 As shown, the disposable pre-filled automatic injection pen includes a pen shell 110. A pen cap plug 111 is integrally formed at the bottom of the pen shell 110. A pen cap 120 is inserted into the outer surface of the pen cap plug 111. The pen cap 120 is inserted into the pen cap plug 111 through an interference fit, so that the pen cap 120 and the pen shell 110 are firmly connected and can be quickly disassembled. A pen cap slot 112 is formed on the pen shell 110. A pen shell locking block 131 is fixed on the pen cap 130. The pen shell locking block 131 is engaged with the pen cap slot 112, so that the pen cap 130 is locked onto the top of the pen shell 110, which facilitates the assembly of internal components. An observation window 115 is formed on the surface of the pen shell 110. The observation window 115 penetrates the pen shell 110 and the cartridge positioning block 114, facing the position of the medicine bottle 220, so that the patient can directly see the remaining amount of medicine and the injection progress to confirm whether the injection is completed. A cartridge positioning ring 113 is fixed to the lower end of the pen casing 110. Cartridge positioning blocks 114 are symmetrically fixed to both sides of the upper surface of the cartridge positioning ring 113. A cartridge 210 is engaged between the two sets of cartridge positioning blocks 114. A top protrusion 211 is fixed to the upper end of the cartridge 210, and the top protrusion 211 fits against the top surface of the cartridge positioning block 114. Cartridge claws 212 are symmetrically fixed to the bottom of the cartridge 210. A cartridge limiting groove 116 is symmetrically opened at the bottom of the cartridge positioning ring 113 to engage with the cartridge claws 212. Limiting ridges 214 matching the width of the cartridge positioning blocks 114 are symmetrically fixed to both the upper and lower ends of the cartridge 210. A medicine bottle 220 is engaged inside the cartridge 210. A medicine bottle claw 213 is symmetrically fixed to the bottom of the cartridge 210, and the medicine bottle claw 213 fits against the bottom of the medicine bottle 220. When the two sets of vial clamps 213 are closed, the distance between them is less than the outer diameter of the vial 220. The cartridge 210 is circumferentially positioned by the engagement of the limiting ridge 214 and the cartridge positioning block 114, and is axially and upwardly positioned by the contact of the top protrusion 211 with the top surface of the cartridge positioning block 114. It is axially and downwardly positioned by the engagement of the cartridge clamp 212 with the cartridge limiting groove 116, thus achieving dual axial and circumferential fixation of the cartridge 210 and ensuring that the cartridge 210 will not move or rotate during injection. The vial 220 is axially and downwardly positioned by the lifting of the vial clamp 213 and radially positioned by the inner wall of the cartridge 210, thus achieving precise positioning of the vial 220 and ensuring that the piston of the vial 220 is coaxial with the syringe 350, avoiding needle jamming or leakage caused by uneven injection force. The needle end of the vial 220 is sealed with a needle sleeve 221 in the shape of an inverted frustum. The pen cap 120 has an integrally connected elastic claw 121 inside. The top of the elastic claw 121 is set with an arc-shaped protrusion with the same shape as the needle sleeve 221. The elastic claw 121 engages with the upper surface of the needle sleeve 221. When the pen cap 120 is inserted into the pen cap plug 111, the arc-shaped protrusion of the elastic claw 121 is precisely engaged with the upper inclined surface of the inverted frustum-shaped needle sleeve 221. When the pen cap 120 is removed, the elastic claw 121 hooks and pulls out the needle sleeve 221 simultaneously through friction and the self-locking action of the inclined surface. This combines the two operations of removing the pen cap 120 and removing the needle sleeve 221 into one, simplifying the operation steps, avoiding injection failure due to the patient forgetting to remove the needle sleeve 221, and reducing the opportunity for hand contact with the needle, thus improving the safety of use. A drive cylinder 360 is provided between the pen casing 110 and the medicine bottle 220. The bottom of the drive cylinder 360 has an integrally formed pressure surface 361. The needle of the medicine bottle 220 is located inside the pressure surface 361, forming a hidden needle structure, so that the patient cannot see the needle during injection, reducing their fear. A connecting piece 362 is symmetrically fixed to the top of the drive cylinder 360. The connecting piece 362 has a limiting opening 363. Drive cylinder spring pieces 215 are symmetrically fixed to both sides of the medicine bottle 210. A locking protrusion 216 is fixed to the top of the side wall of the drive cylinder spring piece 215. The locking protrusion 216 cooperates with the limiting opening 363. The top of the connecting piece 362 abuts against the bottom of the outer locking cylinder 310; the upper part of the upper limit opening 363 of the connecting piece 362 is limited by the locking protrusion 216 on the outside of the drive cylinder spring piece 215, so that the drive cylinder cannot move towards the pen cap 120. At the same time, under the action of the connecting piece 362 abutting against the outer locking cylinder, the drive cylinder 360 cannot move towards the pen cap 130 under normal circumstances, thus achieving axial limitation of the drive cylinder 360 under normal circumstances. Only when an external force is applied during injection can the drive cylinder 360 move towards the pen cap 130 and push the outer locking cylinder. The top of the connecting piece 362 is fitted with an outer locking cylinder 310. Symmetrical first spring positioning protrusions 312 are fixed on both sides of the bottom surface of the outer locking cylinder 310. A first spring 320 is engaged between the first spring positioning protrusions 312 and the outer locking cylinder 310. Under the action of the inner locking cylinder 330 and the outer locking cylinder 310, the first spring 320 is compressed. A lower limit protrusion 313 is fixed to the outer wall of the outer locking cylinder 310, and an upper limit protrusion 337 is fixed to the outer wall of the inner locking cylinder 330. The outer walls of both the lower limit protrusion 313 and the upper limit protrusion 337 are fitted with the inner wall of the first spring 320. The compressed first spring 320 allows the outer locking cylinder 310 to be pushed by the driving cylinder 360 while simultaneously compressing the first spring 320. An elastic pressure plate 332 is fixed at the bottom of the inner locking cylinder 330. The elastic pressure plate 332 abuts against the top surface of the medicine bottle 220. The design of the elastic pressure plate 332 ensures that the medicine bottle 220 is stably installed in the medicine cartridge 210 and avoids rigid contact between the medicine bottle 220 and the inner locking cylinder. The inner locking cylinder 330 is internally fitted with a limiting cylinder 410, which allows the limiting cylinder 410 to move vertically within the inner locking cylinder 330 and not circumferentially. A second elastic limiting part 335 is fixed on the inner locking cylinder 330 to cooperate with the limiting cylinder 410, limiting the initial position of the limiting cylinder 410. The limiting cylinder 410 has an ear groove 411 inside. The top of the syringe 350 is fixed with an ear 355 that cooperates with the ear groove 411. The bottom of the syringe 350 abuts against the piston inside the medicine bottle 220. The inner locking cylinder 330 limits the limiting cylinder 410, and then the limiting cylinder 410 limits the syringe 350, thereby indirectly limiting the syringe 350 and ensuring that the inner locking cylinder 330 can subsequently limit and lock the syringe 350. A positioning rod 354 is inserted inside the syringe 350. A second spring 353, in a compressed state, is sleeved between the positioning rod 354 and the syringe 350. The length of the second spring 353 in its uncompressed state is greater than the axial length of the syringe 350. The top of the second spring 353 abuts against the positioning rod 354, and the bottom of the second spring 353 abuts against the inner bottom surface of the syringe 350. The top of the positioning rod 354 is engaged inside the pen cap 130, and an injection device engaged with the positioning rod 354 is fixed at the middle position inside the pen cap 130. The cylinder slot 132; through the above structural design, after the second spring 353 is fully compressed into the injection cylinder 350, and then limited by the pen cap 130, where the pen cap 130 is locked to the top of the pen shell 110, and at the same time the pen cap 120 abuts against the top of the inner locking cylinder 330, under the restoring force of the second spring 353, it will tightly press against the injection cylinder 350, so that the second spring 353 has a large elastic potential energy, providing power for the subsequent movement of the injection cylinder 350 to the pen cap 120 side for injection; The upper and lower ends of the outer surface of the syringe 350 are respectively provided with an upper slot 352 and a lower slot 351. The inner locking cylinder 330 is provided with a first elastic limiting part 333. The outer surface of the first elastic limiting part 333 is provided with an outward protrusion 334. The outward protrusion 334 is tightly fitted with the inner wall of the outer locking cylinder 310. By setting the outward protrusion 334 tightly fitted with the inner wall of the outer locking cylinder 310, the first elastic limiting part 333 cannot be squeezed outward by the restoring force of the second spring 353, so that the first elastic limiting part 333 is kept engaged with the lower slot 351, and the inner locking cylinder 330 achieves initial limiting and locking of the syringe 350. The inner locking cylinder 330 has symmetrical slots 338 on its top. Inside the top of the inner locking cylinder 330, there is a sound-emitting cylinder 340 that can strike the inner surface of the pen cap 130 to produce sound. The inner wall of the sound-emitting cylinder 340 is tightly fitted to the outer wall of the limiting cylinder 410. Symmetrically fixed to the side wall of the sound-emitting cylinder 340 are extension blocks 341 that mate with the slots 338. The opening directions of the slots 338 and extension blocks 341 are the same as the direction of the outer locking cylinder directional block 311. Symmetrically fixed to the side wall of the sound-emitting cylinder 340 are inner locking cylinder locking blocks 342. Symmetrically fixed to the upper side wall of the inner locking cylinder 330 are sound-emitting cylinder locking grooves 339 that mate with the inner locking cylinder locking blocks 342. The inner wall of the sound-emitting cylinder 340 is tightly fitted to the outer wall of the limiting cylinder 410. A latching groove 343 is provided at the bottom of the extension block 341. The inner locking cylinder block 342 is held firmly against the outer wall of the limiting cylinder 410 in the initial state, preventing the inner locking cylinder block 342 from being squeezed and deformed by the first spring 320. This allows the inner locking cylinder block 342 to be firmly engaged in the sound tube slot 339, making the sound tube 340 stably installed on the top of the inner locking cylinder 330. After the injection is completed, the limiting cylinder 410 moves downward and disengages from the limiting of the inner locking cylinder block 342. This causes the inner locking cylinder block 342 to be squeezed and deformed by the restoring force of the first spring 320, thus disengaging from the sound tube slot 339. At this time, under the restoring force of the first spring 320, the sound tube 340 is pushed to collide with the inner surface of the pen cap 130, producing a clicking sound. The top of the outer locking cylinder 310 is symmetrically provided with a first elastic part 316, which is configured as an inwardly curved arc. The bottom of the outer side of the second elastic limiting part 335 is provided with a second elastic part 336, which is configured as an outwardly curved arc. When the outer locking cylinder 310 moves upward and gradually releases the restriction on the outward protrusion 334 of the first elastic limiting part 333, the first elastic limiting part 333 will be squeezed open by the restoring force of the second spring 353 and then pop out from the lower slot 351, thereby releasing the limiting lock on the syringe 350. At this time, under the elastic restoring force of the second spring 353, the syringe 350 pushes the piston inside the medicine bottle 220 to move towards the pen cap 120 to perform the injection action. Since the syringe 350 moves downward, there is a part of the free travel in the limiting cylinder 410. During this part of the travel, the downward movement of the syringe 350 will not drive the limiting cylinder 410. The syringe 350 moves downward until the latch 355 at the top of the syringe 350 contacts the bottom surface of the latch groove 411 inside the limiting cylinder 410. Only then will the syringe 350 move downward, causing the limiting cylinder 410 to move downward. At this time, the downward movement of the limiting cylinder 410 will push the second elastic limiting part 335 to open outward until the syringe 350 completes the injection. Because the second elastic limiting part 335 opens outward, the first elastic part 316 is limited by the action of the second elastic part 336, thereby preventing the outer locking cylinder from continuing to move upward. After the injection is completed, the outer locking cylinder 310 will be pushed back to its original position by the restoring force of the first spring 320, until the driving cylinder 360 is limited by the latch protrusion 216. Even if the driving cylinder 360 is pushed again to move the outer locking cylinder 310, it will continue to be limited by the second elastic part 336 and cannot be pushed, thus preventing reuse. The inner wall of the pen casing 110 is symmetrically provided with directional grooves 117. The outer wall of the bottom end of the outer locking cylinder 310 is symmetrically fixed with an outer locking cylinder directional block 311 that mates with the directional groove 117. The outward protrusion 334 and the second elastic limiting part 335 are both arranged on the same side as the outer locking cylinder directional block 311. The side wall of the pen cap 130 is symmetrically fixed with a pen cap directional block 133 that mates with the directional groove 117. The outer locking cylinder 310 is symmetrically fixed with limiting spring pieces 314 on both sides. The inner wall of the limiting spring piece 314 is fixed with a slider 315. The outer wall of the bottom of the inner locking cylinder 330 is provided with a sliding groove 331 that mates with the slider 315. Through the design of the above structure, the outer locking cylinder 310, inner locking cylinder 330, injection cylinder 350, pen cap 130 and other structures all have directional installation guidance, and the whole assembly process is clear, simple and convenient. This invention achieves automatic injection by pressing the injection pen after the pressure surface 361 of the drive cylinder 360 contacts the patient's skin. Simultaneously, the design of removing the needle cap 120 to remove the needle sheath 221 makes it simpler, more convenient, and saves time and effort for the patient. The specific working principle is as follows: In use, first remove the pen cap 120. The elastic claw 121 inside the pen cap 120 simultaneously pulls out the needle sleeve 221 on the medicine bottle 220. Then, the contact surface 361 of the drive cylinder 360 is vertically attached to the skin at the injection site. Press the pen body firmly, and the drive cylinder 360 moves upward and pushes the outer locking cylinder 310 upward. The inner wall of the outer locking cylinder 310 disengages from the limit of the outward protrusion 334 on the first elastic limiting part 333. The first elastic limiting part 333 is squeezed by the second spring 353 and opens outward. At this time, the first elastic limiting part 333 disengages from the lower slot 351 of the injection cylinder 350, completing the locking and unlocking action of the injection cylinder 350. At this time, the injection cylinder 350 moves rapidly downward under the restoring force of the second spring 353, pushing the piston inside the medicine bottle 220 and completing the injection of medicine, realizing automatic injection. During the injection, the patient can observe the injection process through the observation window 115; After injection, the limiting cylinder 410 is moved downward by the injection cylinder 350, thereby releasing the limiting of the inner locking cylinder block 342. At this time, under the restoring force of the first spring 320, the inner locking cylinder block 342 will be squeezed, causing the inner locking cylinder block 342 to retract inward and disengage from the sound tube slot 339. At this time, under the restoring force of the first spring 320, the sound tube 340 moves upward and impacts the inner surface of the pen cap 130, emitting a clicking reminder sound. Since the bottom of the slot 338 opened at the top of the inner locking cylinder 330 is located below the sound tube slot 339, the two sections of the top structure of the inner locking cylinder 330 separated by the slot 338 have a certain elastic deformation. Therefore, under the push of the restoring force of the first spring 320, the inner locking cylinder block 342 can be squeezed out of the sound tube slot 339. After the inner locking cylinder 330 releases its lock on the injection cylinder 350, the injection cylinder 350 moves rapidly downward under the restoring force of the second spring 353 to perform injection. Because the retaining groove 411 inside the limiting cylinder 410 has a certain length, the injection cylinder 350 will continue to move rapidly downward during the initial injection phase until the retaining lug 355 at the top of the injection cylinder 350 contacts the bottom surface of the retaining groove 411. At this point, the injection cylinder 350 will drive the limiting cylinder 410 to continue moving downward. As the limiting cylinder 410 is driven downward, it gradually compresses the second elastic limiting part 335, causing the second elastic limiting part 335 to open outward, thereby causing the second elastic part 336 to expand outward. Meanwhile, as the outer locking cylinder 310 moves upward, it also... The first elastic part 316 will gradually come into contact with the second elastic part 336, thereby blocking and limiting the first elastic part 316 by the second elastic part 336, so that the outer locking cylinder 310 can no longer move. At this time, the lower part of the upper limit opening 363 of the drive cylinder 360 is also limited by the locking protrusion 216. At this time, the entire injection operation is completed. When the patient removes the injection pen, the outer locking cylinder 310 will be pushed back to its original position by the restoring force of the first spring 320, thereby driving the drive cylinder 360 to move back to its original position synchronously until the upper part of the upper limit opening 363 of the drive cylinder 360 is limited by the locking protrusion 216 on the outside of the drive cylinder spring 215, and then stops moving. The drive cylinder 360 then hides the needle of the medicine bottle 220 again. If the drive cylinder 360 is accidentally touched later, it will be unable to move further because the first elastic part 316 on the outer locking cylinder 310 is limited and blocked by the second elastic part 336, thus preventing repeated use. The assembly process of this invention is as follows: Pre-filled component assembly: First, insert the cartridge 210 into the pen shell 110 under the limiting action of the limiting ridge 214 and the cartridge positioning block 114 until the top protrusion 211 fits against the cartridge positioning block 114. At the same time, the cartridge claw 212 deforms and passes through the cartridge positioning ring 113 and then returns to its original shape to engage with the cartridge limiting groove 116, thereby achieving the installation limitation of the cartridge 210. Next, insert the vial 220 with needle sheath 221 into the vial 210 until the bottom of the vial 220 is stopped and abutted by the vial clip 213; Next, insert the connecting piece 362 on the drive cylinder 360 into the pen shell 110 along the gap between the two sets of cartridge positioning blocks 114 until the locking protrusion 216 on the drive cylinder spring piece 215 enters the limiting opening 363. Finally, insert the pen cap 120 into the pen cap plug 111 on the pen shell 110. At this time, the elastic claw 121 just locks the needle sleeve 221. Automatic injection assembly: First, insert the sound tube 340 into the inner locking tube 330 under the action of the extension block 341 and the slot 338 until the inner locking tube block 342 is elastically engaged with the sound tube slot 339. Next, the top of the first spring 320 is locked in the buckle groove 343, and then the first spring 320 is sleeved on the outside of the outer locking cylinder 310 and limited by the first spring positioning protrusion 312; at this time, the inner locking cylinder 330 is slidably connected together under the action of the sliding groove 331 and the slider 315, and the first spring 320 is supported by the lower limit protrusion 313 and the upper limit protrusion 337. Then the limiting cylinder 410 is inserted along the circular direction of the inner wall of the inner locking cylinder 330 until it is stopped and limited by the second elastic limiting part 335; Finally, press down on the pen cap 130, and insert the assembly consisting of the pen cap 130, the syringe 350, the second spring 353, and the positioning rod 354 into the limiting cylinder 410 under the action of the top ear 355 and the ear groove 411 of the syringe 350, until the lower groove 351 at the bottom of the syringe 350 elastically engages with the first elastic limiting part 333, thus completing the limiting and locking of the syringe 350. Assembly of the pre-filled component and the automatic injection component: Clamp the outer locking cylinder 310 and press the pen cap 130. Insert the entire automatic injection component into the pen shell 110 under the positioning and sliding action of the outer locking cylinder directional block 311 and the directional groove 117 until the pen cap 130 is engaged with the pen shell 110 under the positioning and sliding action of the pen cap directional block 133 and the directional groove 117. When the pen shell locking block 131 and the pen cap locking groove 112 are elastically engaged, the overall assembly is achieved.

[0025] In the description of this invention, it should be noted that the terms "upper," "lower," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship conventionally understood by those skilled in the art. These terms are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0026] The above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described herein. Although the present invention has been described in detail with reference to the above embodiments, the present invention is not limited to the specific embodiments described above. Therefore, any modifications or equivalent substitutions to the present invention, as well as all technical solutions and improvements that do not depart from the spirit and scope of the invention, are covered within the scope of the claims of the present invention.

Claims

1. A disposable pre-filled automatic injection pen, characterized in that, include: A pre-filled assembly, comprising a pen casing (110) and a pen cap (120) that engage with each other, wherein a medicine bottle (220) is disposed in the lower part of the pen casing (110); and An automatic injection assembly includes an outer locking cylinder (310) movably disposed inside the pen casing (110), the outer locking cylinder (310) elastically sleeved outside the inner locking cylinder (330), an injection cylinder (350) slidably connected inside the inner locking cylinder (330), the bottom of the injection cylinder (350) abutting against the piston inside the medicine bottle (220); the injection cylinder (350) is elastically connected to the pen cap (130), the pen cap (130) being snapped onto the top of the pen casing (110); an upper slot (352) and a lower slot (351) are respectively provided at the upper and lower ends of the outer surface of the injection cylinder (350). The inner locking cylinder (330) is provided with a first elastic limiting part (333), which cooperates with the upper slot (352) and the lower slot (351) respectively; the outer surface of the first elastic limiting part (333) is provided with an outward protrusion (334), which is tightly fitted with the inner wall of the outer locking cylinder (310); a driving cylinder (360) is provided between the pen shell (110) and the medicine bottle (220) for limiting sliding; the bottom of the driving cylinder (360) extends to the outside of the pen shell (110), and the top of the driving cylinder (360) abuts against the bottom of the outer locking cylinder (310).

2. The disposable pre-filled automatic injection pen according to claim 1, characterized in that, The bottom of the pen case (110) is integrally provided with a pen cap plug (111), and the pen cap (120) is inserted into the outer surface of the pen cap plug (111); the pen case (110) is provided with a pen cap slot (112), and a pen case block (131) is fixed on the pen cap (130), and the pen case block (131) is engaged with the pen cap slot (112); the surface of the pen case (110) is provided with an observation window (115).

3. The disposable pre-filled automatic injection pen according to claim 2, characterized in that, A cartridge positioning ring (113) is fixed to the lower end of the pen shell (110). Cartridge positioning blocks (114) are symmetrically fixed to both sides of the upper surface of the cartridge positioning ring (113). The observation window (115) passes through the pen shell (110) and the cartridge positioning blocks (114). A cartridge (210) is engaged between the two sets of cartridge positioning blocks (114). A top protrusion (211) is fixed to the upper end of the cartridge (210). The top protrusion (211) fits against the top surface of the cartridge positioning block (114). Cartridge claws (212) are symmetrically fixed to the bottom of the cartridge (210). Cartridge limiting grooves (116) that engage with the cartridge claws (212) are symmetrically opened at the bottom of the cartridge positioning ring (113). Limiting edges (214) that match the width of the cartridge positioning blocks (114) are symmetrically fixed to both the upper and lower ends of the cartridge (210). The medicine bottle (220) is fitted inside the medicine cartridge (210). The bottom of the medicine cartridge (210) is symmetrically fixed with medicine bottle claws (213). The medicine bottle claws (213) fit against the bottom of the medicine bottle (220). The distance between the two sets of medicine bottle claws (213) is smaller than the outer diameter of the medicine bottle (220). The needle end of the medicine bottle (220) is sealed with a needle sleeve (221) in the shape of an inverted frustum. The pen cap (120) is integrally connected with an elastic claw (121). The top of the elastic claw (121) is set as an arc protrusion with the same shape as the needle sleeve (221). The elastic claw (121) engages with the upper surface of the needle sleeve (221).

4. The disposable pre-filled automatic injection pen according to claim 3, characterized in that, A first spring (320) in a compressed state is connected between the outer locking cylinder (310) and the inner locking cylinder (330). A syringe holder (132) is provided at the middle position inside the pen cap (130). A positioning rod (354) is fitted inside the syringe holder (132). The positioning rod (354) is inserted into the syringe (350). A second spring (353) in a compressed state is located between the positioning rod (354) and the syringe (350). The length of the second spring (353) in its uncompressed state is greater than the axial length of the syringe (350). The top of the second spring (353) abuts against the positioning rod (354), and the bottom of the second spring (353) abuts against the positioning rod (354). The bottom surface of the syringe (350) abuts against the inside; the bottom of the inner locking cylinder (330) is provided with an elastic pressure plate (332), which abuts against the top surface of the medicine bottle (220); the bottom of the drive cylinder (360) is integrally formed with a pressure surface (361), the needle of the medicine bottle (220) is located inside the pressure surface (361), the top of the drive cylinder (360) is symmetrically fixed with a connecting piece (362), the connecting piece (362) has a limiting opening (363), the two sides of the syringe (210) are symmetrically fixed with drive cylinder spring pieces (215), the top of the side wall of the drive cylinder spring piece (215) is fixed with a locking protrusion (216), and the locking protrusion (216) cooperates with the limiting opening (363).

5. The disposable pre-filled automatic injection pen according to claim 4, characterized in that, The outer locking cylinder (310) has symmetrically fixed first spring positioning protrusions (312) on both sides of its bottom surface. The first spring (320) is engaged between the outer locking cylinder (310) and the first spring positioning protrusions (312). The outer wall of the outer locking cylinder (310) has a lower limit protrusion (313) fixed on it. The outer wall of the inner locking cylinder (330) has an upper limit protrusion (337) fixed on it. The outer walls of the lower limit protrusion (313) and the upper limit protrusion (337) are both in contact with the inner wall of the first spring (320).

6. The disposable pre-filled automatic injection pen according to claim 5, characterized in that, The inner locking cylinder (330) is fitted with a limiting cylinder (410) inside, and a second elastic limiting part (335) that cooperates with the limiting cylinder (410) is fixed on the inner locking cylinder (330). A retaining groove (411) is opened inside the limiting cylinder (410), and a retaining ear (355) that cooperates with the retaining groove (411) is fixed on the top of the injection cylinder (350).

7. The disposable pre-filled automatic injection pen according to claim 6, characterized in that, The inner wall of the pen casing (110) is symmetrically provided with directional grooves (117), and the outer wall of the bottom end of the outer locking cylinder (310) is symmetrically fixed with an outer locking cylinder directional block (311) that cooperates with the directional groove (117). The outward protrusion (334) and the second elastic limiting part (335) are both provided on the same side as the outer locking cylinder directional block (311). The side wall of the pen cap (130) is symmetrically fixed with a pen cap directional block (133) that cooperates with the directional groove (117). The outer locking cylinder (310) is symmetrically fixed with limiting spring pieces (314) on both sides. The inner wall of the limiting spring piece (314) is fixed with a slider (315). The outer wall of the bottom of the inner locking cylinder (330) is provided with a sliding groove (331) that cooperates with the slider (315).

8. The disposable pre-filled automatic injection pen according to claim 7, characterized in that, The top of the inner locking cylinder (330) is symmetrically provided with slots (338). Inside the top of the inner locking cylinder (330) is a sound-emitting cylinder (340) that can strike the inner surface of the pen cap (130) to produce sound. The side wall of the sound-emitting cylinder (340) is symmetrically fixed with extension blocks (341) that cooperate with the slots (338). The opening direction of the slots (338) and the extension blocks (341) is the same as the direction of the outer locking cylinder directional block (311). The sound-emitting tube (340) is symmetrically fixed with an inner locking tube block (342) on its side wall. The upper side wall of the inner locking tube (330) is symmetrically provided with a sound-emitting tube slot (339) that cooperates with the inner locking tube block (342). The inner wall of the sound-emitting tube (340) is tightly fitted with the outer wall of the limiting tube (410). The bottom of the extension block (341) is provided with a buckle groove (343), which is locked on the upper surface of the first spring (320).

9. The disposable pre-filled automatic injection pen according to claim 8, characterized in that, The top of the outer locking cylinder (310) is symmetrically provided with a first elastic part (316), which is configured as an inwardly curved arc. The bottom of the outer side of the second elastic limiting part (335) is fixed with a second elastic part (336), which is configured as an outwardly curved arc.

Images