Needle retracting spring locking excitation mechanism for automatic injection pen

Abstract

The utility model provides a narrowing spring locking excitation mechanism for an automatic injection pen, which comprises a push rod, a retraction sleeve, a narrowing spring base, a narrowing spring and the like, and is arranged around the narrowing spring, so that the locking can be ensured to be safe and cannot be easily triggered and unlocked; unlocking excitation can be achieved only when the push rod pushes medicine to complete injection, pushing force is automatically provided by the needle retracting spring in the unlocking excitation process, dependence on the elastic force of the tail section of the injection spring can be eliminated, and the unlocking excitation process is convenient and rapid.

Description

Technical Field

[0001] This utility model relates to a mechanism for locking and activating the needle retraction spring in an automatic injection pen, belonging to the field of medical syringes. Background Technology

[0002] An automatic injection pen is a syringe product that is convenient for patients or the general public to operate. During production, the manufacturer pre-fills the syringe with medication, forming a pre-filled syringe (PFS, also known as a drug-loaded syringe). Figure 4 As shown; the PFS is then installed into an automatic injection device to form an automatic injection pen for transportation and sale. After receiving the automatic injection pen, the consumer uses it as needed, removing the pen cap and pressing it onto the patient's injection site to initiate the injection. Finally, the pen is removed, completing the automatic injection of the medication. Compared to traditional syringes, it eliminates the need for drawing, inserting, and pushing medication with a disposable syringe, making operation more convenient and ensuring a guaranteed dosage without deviations due to operator inexperience.

[0003] Currently, there are many automated injection pens for PFS (Prophylactic Assistive Device) on the market with disposable, fully automated injection functions, which makes it convenient for patients to use. However, due to regulatory requirements, the needle must be covered before and after use to prevent needle injury. Therefore, it generally requires two sets of spring systems to perform the functions of pushing the drug into the injection and removing the needle for covering. As a result, the structure of automated injection pens is generally quite complex, which makes the assembly of automated injection devices with PFS also more complicated.

[0004] In particular, the needle retraction spring needs to be reliably locked during transportation and also needs to remain reliably locked during the initial use of the automatic injection pen (needle insertion and drug injection). Once the drug injection is completed, it needs to be unlocked in time to unfold and realize the needle retraction action (needle removal and needle concealment).

[0005] Therefore, the locking and triggering mechanism of the retractable spring needs to be cleverly designed to achieve reliable safety locking and convenient and quick unlocking.

[0006] Existing automatic injection pens often use the elastic force of the injection spring after it unfolds to unlock the locking mechanism of the needle retraction spring. However, in this case, if sufficient unlocking force can still be provided, the elastic force of the entire injection spring needs to be extremely large, and the residual force of the injection spring should not affect the unfolding and retraction of the needle retraction spring. Therefore, the mechanism is often quite complex.

[0007] In response to the above situation, it is necessary to design a more ingenious mechanism to safely lock the retracting needle spring and unlock it for activation. Utility Model Content

[0008] The purpose of this invention is to provide a needle-retracting spring locking and triggering mechanism for an automatic injection pen. The mechanism is designed around the needle-retracting spring to ensure that the locking is secure and cannot be easily triggered to unlock. Unlocking and triggering can only be achieved when the injection is completed by pushing the push rod. During unlocking and triggering, the needle-retracting spring provides the pushing force on its own, which can eliminate the dependence on the end elastic force of the injection spring. The unlocking and triggering process is convenient and quick.

[0009] To achieve the above-mentioned utility model objectives, this utility model provides a needle retraction spring locking and actuation mechanism for an automatic injection pen, including a push rod, a retractable sleeve, a needle retraction spring base, and a needle retraction spring.

[0010] The needle-retracting spring base is a cylinder with openings at both ends, containing a spring cylinder. The bottom of the spring cylinder extends outward to form a spring seat.

[0011] The take-off spring is sleeved on the spring sleeve, and the bottom of the take-off spring abuts against the spring seat;

[0012] The inside of the spring cylinder is a connecting cavity;

[0013] The lower part of the retractable sleeve has a stepped surface, and the top of the take-up spring abuts against the stepped surface;

[0014] A connecting sleeve is provided below the stepped surface of the retractable sleeve. The diameter of the connecting sleeve is smaller than that of the stepped surface and also smaller than that of the inner diameter of the spring sleeve.

[0015] The lower part of the connecting sleeve of the retractable sleeve is an elastic needle retraction fixing claw. The bottom of the needle retraction fixing claw protrudes outward to form a needle retraction fixing hook. The upper part of the needle retraction fixing hook has an inclined needle retraction guide.

[0016] The interior of the connecting cylinder and the needle retaining claw forms a push rod guide cavity;

[0017] The lower part of the push rod is the push rod cylinder, which is a cylindrical tube; the push rod cylinder can slide along the axis within the push rod guide cavity;

[0018] The top of the push rod cylinder has an axial clearance cavity; the clearance cavity is located in the same direction as the needle retraction fixing claw.

[0019] When the take-off spring needs to be in a compressed and locked state, the connecting sleeve of the retractable sleeve is located inside the spring sleeve of the take-off spring base, the take-off fixing claw passes through the spring seat, and the take-off fixing hook hooks onto the bottom of the spring seat; the cylindrical section of the push rod tube of the push rod is located inside the push rod guide cavity; at this time, the inner side of the take-off fixing claw is blocked by the cylindrical section of the push rod tube and cannot retract inward, thus ensuring the connection between the retractable sleeve and the take-off spring base, so that both ends of the take-off spring are fixed and in a reliable compressed and locked state;

[0020] When the needle-retracting spring needs to be in the unlocked and activated state, the push rod cylinder of the push rod moves downward, causing the cylindrical section to leave the push rod guide cavity. The clearance cavity at the top of the push rod cylinder moves into the push rod guide cavity and is located next to the needle-retracting fixing claw. At this time, the inside of the needle-retracting fixing claw is no longer in a position to move. Then, under the action of the needle-retracting spring, the top of the needle-retracting spring pushes the stepped surface at the bottom of the sleeve body, causing the retracting sleeve to tend to move upward. This causes the needle-retracting fixing claw to move upward as well. The needle-retracting guide at the top of the needle-retracting hook contacts the bottom of the spring seat, converting the upward force into the force of the needle-retracting fixing claw to contract and deform inward. This causes the needle-retracting fixing claw to slide along the bottom of the spring seat through the needle-retracting guide. Finally, the needle-retracting fixing claw completely disengages from the bottom of the spring seat and enters the spring cylinder, so that the needle-retracting spring is in an unfoldable state.

[0021] As a further improvement of this utility model, the spring seat of the needle retraction spring base extends outward to form a base fixing claw;

[0022] The needle retraction spring base is fixedly installed inside the pen case via the base fixing claw;

[0023] The bottom of the take-off spring is fixed to the take-off spring base, and the take-off spring can be unfolded upwards.

[0024] As a further improvement of this utility model, the top of the push rod extends outward to form a fixing claw, the size of which is larger than the inner diameter of the connecting cylinder of the retractable sleeve. When the retracting spring is released, the fixing claw at the top of the push rod abuts against the upper part of the connecting cylinder of the retractable sleeve. When the retractable sleeve is pushed upward by the retracting spring, it simultaneously drives the push rod to move upward.

[0025] As a further improvement of this utility model, the bottom of the push rod is provided with a piston cone, which is fixedly connected to the piston of the syringe.

[0026] The automatic injection pen's needle-retracting spring locking mechanism of this invention utilizes the cylindrical section of the push rod to abut against the needle-retracting fixing claw, achieving a safe and reliable locking. As the push rod moves, the clearance cavity moves to the edge of the needle-retracting fixing claw, allowing the claw to retract and deform inward. Under the action of the needle-retracting spring, the mechanism unlocks. Unlocking does not require the injection spring to provide elasticity; the unlocking force is entirely provided by the needle-retracting spring.

[0027] The automatic injection pen's needle-retracting spring locking and actuation mechanism of this utility model has an ingenious structural design. It can reliably and safely lock the needle-retracting spring, and can also quickly unlock it as the push rod moves, making unlocking convenient. Attached Figure Description

[0028] Figure 1 This is an overall outline drawing of the automatic injection pen of the present invention;

[0029] Figure 2 This is a schematic diagram of the pre-assembled module of the automatic injection pen of the present invention;

[0030] Figure 3 This is an exploded view of the components of the automatic injection pen of the present invention;

[0031] Figure 4 This is a schematic diagram of the overall structure of a prefilled syringe (PFS).

[0032] In the diagram, 1-Prefilled syringe (PFS); 11-Sliding sleeve; 12-Piston; 13-Injection needle; 14-Cap (also known as protective sheath); 15-Flange (also known as flange).

[0033] Figure 5 This is a schematic diagram of the overall structure of the lower pen shell of the present invention.

[0034] Figure 6 This is a cross-sectional view of the internal structure of the lower pen shell of the present invention;

[0035] Figure 7 This is a structural outline of the pen cap of the present invention;

[0036] Figure 8 This is a cross-sectional view of the internal structure of the pen cap of the present invention;

[0037] Figure 9 This is an overall structural outline of the excitation sleeve of the present invention;

[0038] Figure 10 This is a partial cross-sectional schematic diagram of the excitation sleeve of the present invention;

[0039] Figure 11 This is a schematic diagram of the structure of the PFS mounting sleeve of the present invention;

[0040] Figure 12 This is a schematic diagram of the structure of the PFS of the present invention installed in the lower pen shell component;

[0041] Figure 13 This is an overall cross-sectional view of the PFS after it has been installed in the lower pen shell pre-assembly module.

[0042] Figure 14 This is a schematic diagram of the overall structure of the upper pen shell of the present invention;

[0043] Figure 15 This is a cross-sectional view of the internal structure of the upper pen shell of the present invention;

[0044] Figure 16This is a schematic diagram of the overall structure of the push rod of the present invention;

[0045] Figure 17 This is a cross-sectional view of the internal structure of the push rod of the present invention;

[0046] Figure 18 This is an overall structural outline drawing of the safety pin of the present invention;

[0047] Figure 19 This is a cross-sectional view of the internal structure of the safety pin of the present invention;

[0048] Figure 20 This is an overall structural outline of the retractable sleeve of the present invention;

[0049] Figure 21 This is a cross-sectional view of the internal structure of the retractable sleeve of the present invention;

[0050] Figure 22 This is an overall structural diagram of the injection spring support of the present invention;

[0051] Figure 23 A schematic diagram of the assembly of the push rod, injection spring, and injection spring support on the retraction sleeve;

[0052] Figure 24 This is an overall structural outline of the needle retraction spring base of the present invention;

[0053] Figure 25 This is a cross-sectional view of the internal structure of the needle retraction spring base of the present invention;

[0054] Figure 26 This is an overall structural outline of the upper pen shell pre-assembly module of the present invention;

[0055] Figure 27 This is a cross-sectional view of the internal structure of the upper pen shell pre-assembly module of the present invention;

[0056] Figure 28 This is the fully assembled, unused state of the automatic injection system of the present invention.

[0057] Figure 29 The automatic injection process of this invention is in step 1, with the pen cap removed.

[0058] Figure 30 This is a schematic diagram of the initial stage of step 2 in the automatic injection process of the present invention. Figure 1 ;

[0059] Figure 31 This is a schematic diagram of the initial stage of step 2 in the automatic injection process of the present invention. Figure 2 ;

[0060] Figure 32 This is a schematic diagram of step 2.1 of the automatic injection process of the present invention;

[0061] Figure 33 This is a schematic diagram of step 2.2 of the automatic injection process of the present invention;

[0062] Figure 34 This is a schematic diagram of the initial stage of step 2.3 of the automatic injection process of the present invention;

[0063] Figure 35 This is a schematic diagram of step 2.3 of the automatic injection process of the present invention;

[0064] Figure 36 This is a schematic diagram showing the imminent termination of step 2.3 of the automatic injection process of the present invention;

[0065] Figure 37 This is a schematic diagram illustrating steps 2.4 to 2.5 of the automatic injection process of the present invention;

[0066] Figure 38 This is a schematic diagram of step 2.6 of the automatic injection process of the present invention;

[0067] Figure 39 This is a schematic diagram of step 3 of the automatic injection process of the present invention;

[0068] Figure 40 This is a schematic diagram of the inward retraction and deformation process of the fixing claw in step 2.1 of the automatic injection process of the present invention. Figure 1 ;

[0069] Figure 41 This is a schematic diagram of the inward retraction and deformation process of the fixing claw in step 2.1 of the automatic injection process of the present invention. Figure 2 ;

[0070] Figure 42 This is a schematic diagram showing the fixing claw sliding inside the sleeve in step 2.3 of the automatic injection process of the present invention.

[0071] Figure 43 This is a schematic diagram illustrating the injection spring pushing the plunger for injection in steps 2.2 and 2.3 of the automatic injection process of the present invention.

[0072] Figure 44 This is a schematic diagram of the movement of the push rod relative to the injection spring support in step 2.3 of the automatic injection process of the present invention.

[0073] Figure 45 This is a schematic diagram illustrating the process of the repositioning cavity continuously approaching the needle-retracting fixing claw at the end of step 2.3 of the automatic injection process of the present invention.

[0074] Figure 46 This is a schematic diagram illustrating the change process of the needle-retracting fixing claw in step 2.5 of the automatic injection process of the present invention.

[0075] Figure 47 This is a schematic diagram of step 2.6 of the automatic injection process of the present invention. Detailed Implementation

[0076] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0077] The purpose of this invention is to provide an automatic injection pen, the overall structure of which, when not in use, is as follows: Figure 1 As shown, from bottom to top, it includes a pen cap 22, a lower pen shell 21, and an upper pen shell 31. An observation window is provided on the lower pen shell 21, through which the internal syringe 11 can be seen through the transparent or also provided-with-an-observation-window PFS mounting sleeve, and through the transparent wall of the syringe 11, the state of the internal medicine can be observed.

[0078] The automatic injection pen of the present invention is manufactured and pre-assembled by an injection device manufacturer into a lower pen shell pre-assembly module 2 and an upper pen shell pre-assembly module 3. These two pre-assembly modules are delivered to the drug manufacturer and then assembled with a pre-filled syringe 1. Figure 2 As shown, the pre-filled syringe 1 is inserted into the lower pen shell pre-assembly module 2, and then the upper pen shell pre-assembly module 3 is installed, thus quickly forming the automatic injection pen of the present invention. All components of the automatic injection pen of the present invention are as follows... Figure 3 As shown.

[0079] Pen shell pre-assembly module 2 ,like Figure 3 As shown, it includes four parts: lower pen housing 21, pen cap 22, excitation sleeve 23, and PFS mounting sleeve 24.

[0080] Pen case 21 ,like Figure 5 , Figure 6 As shown, it includes an outer shell 211, inside which is a shell cavity 212; an observation window 213 is provided on the outer shell 211; the inner wall of the outer shell 211 and inside the shell cavity 212 are provided with two protrusions, namely an excitation guide protrusion 215 and a PFS support protrusion 216; the two protrusions are spaced apart.

[0081] The top of the outer shell 211 is provided with a structure for connecting and fixing with the upper pen shell 31 of the upper pen shell pre-assembly module 3. In this embodiment, a shell fixing groove 218 is provided on the top wall of the outer shell 211.

[0082] Pen Cap 22 ,like Figure 7 , Figure 8As shown, an outer cap shell 221 is provided, and the upper part of the cap shell 221 is a connecting shell 222, which is used to connect with the pen cap mounting surface 217 at the bottom of the lower pen shell 21; preferably, the inner wall of the cap shell 221 is provided with a pen cap positioning protrusion 2222, which matches the size and position of the pen cap positioning groove 2172 to realize the positioning between the lower pen shell 21 and the pen cap 22.

[0083] The pen cap 22 has a protective cap holder 223 inside for storing the protective cap 14 of the pre-filled syringe 1. The upper part of the protective cap holder 223 has two or more cap claws 224 (two cap claws 224 are symmetrically arranged in this embodiment). The cap claws 224 are elastic bodies, and the top of the cap claws 224 forms a cap hook 225 inward. The upper part of the cap hook 225 is an inwardly inclined guide slope. When the pre-filled syringe 1 is installed into the lower pen shell pre-assembly module 2, the bottom of the protective cap 14 contacts the guide slope, so that the cap hook 225 can be pushed outward. At this time, the cap claws 224 elastically deform outward. The bottom of the cap hook 225 is a flat surface. When the pre-filled syringe 1 is installed in the lower pen shell pre-assembly module 2, the protective cap 14 is exactly located inside the protective cap holder 223. At this time, the cap claws 224 elastically reset, so that the cap hook 225 is just locked in the top of the protective cap 14, so that the protective cap 14 is completely located inside the protective cap holder 223. When the pen cap 22 is pulled, the protective cap 14 will be pulled off the syringe 11, thereby exposing the needle 13. Furthermore, the bottom of the protective cap holder 223 is provided with a retainer 226, which keeps the protective cap 14 inside the protective cap holder 223 and prevents it from being lost.

[0084] The lower part of the protective cap holder 223 of the pen cap 22 is provided with several retaining claws 227. The lower part of the retaining claws 227 protrudes outward to form a pen cap retaining protrusion 228. The upper part of the pen cap 22 is limited by the lower pen shell 21 and cannot move upward. The lower part of the pen cap 22 is connected to the excitation sleeve 23 through the pen cap retaining protrusion 228. When it is necessary to remove the pen cap 22, force needs to be applied downward. At this time, the pen cap retaining protrusion 228 moves inward against the bottom of the excitation sleeve 23, causing the retaining claws 227 to retract inward until the pen cap retaining protrusion 228 leaves the excitation sleeve 23, at which point the pen cap 22 can be removed.

[0085] Excitation sleeve 23 ,like Figure 9 , Figure 10 As shown, an excitation cylinder 231 is provided at the bottom, and the excitation cylinder 231 can be slidably installed on the bottom inner side of the outer shell 211 of the lower pen shell 21; the bottom plane of the excitation cylinder 231 shrinks inward to form a protective ring 232, the size of the protective ring 232 matches the pen cap fixing protrusion 228, and can be locked on the pen cap fixing protrusion 228; at the same time, the size of the protective ring 232 is also small, which can prevent fingers or other objects from being inserted and avoid touching the needle 13.

[0086] The excitation sleeve 23 has two excitation plates 233 forming an upward-facing excitation cylinder 231. The excitation plates 233 are slidably disposed within the channel 214 of the lower pen shell 21. An excitation head 234 is provided at the top of the excitation plate 233, and an inclined excitation slope 235 is provided at the top of the excitation head 234. Preferably, the excitation plate 233 is provided with a longitudinal guide groove 236, which matches the excitation guide protrusion 215, and the two together form a sliding guide.

[0087] PFS Installation Sleeve 24 ,like Figure 11 As shown, an installation cylinder 241 is provided, which contains a PFS receiving cavity 242. A support cylinder 243 is provided on the outside of the installation cylinder 241. The support cylinder 243 matches the housing cavity 212 of the lower pen shell 21, and the two are connected and fixed. At this time, the bottom surface 244 of the support cylinder 243 is connected to the PFS support protrusion 216. The top surface of the installation cylinder 241 and the support cylinder 243 are connected to form a PFS flange platform, which is used to support the flange 15 of the PFS.

[0088] like Figure 12 As shown, the lower pen housing 21, the excitation sleeve 23, and the PFS mounting sleeve 24 are pre-assembled together to form a structure that accommodates the PFS. At this time, in order to observe the pre-filled syringe 1 through the observation window 213, the PFS mounting sleeve 24 can be made entirely transparent, or the position of the PFS mounting sleeve 24 between the lower pen housing 21 can be locked, and then a corresponding observation window can also be opened on the wall of the PFS mounting sleeve 24 inside the observation window 213.

[0089] Further as Figure 13 As shown, the pre-filled syringe 1 is inserted into the open opening at the top of the lower pen shell pre-assembly module 2. The syringe 11 is inserted into the PFS mounting sleeve 24, and the protective cap 14 is inserted into the protective cap holder 223. The flange 15 contacts the top surface of the mounting cylinder 241 to achieve positioning. The PFS receiving cavity 242 positions the pre-filled syringe 1 as a whole. Thus, the assembly of the pre-filled syringe 1 and the lower pen shell pre-assembly module 2 is completed.

[0090] Upper Pen Shell Pre-assembly Module 3 ,like Figure 3 As shown, it includes eight parts: upper pen shell 31, push rod 41, injection spring 42, safety pin 43, retraction sleeve 51, injection spring bracket 52, needle retraction spring base 61, and needle retraction spring 62.

[0091] Upper pen case 31 ,like Figure 14 , Figure 15 As shown, it includes an upper shell 311, which is a cylindrical shell with an open lower end and a closed top 312; the lower part of the upper shell 311 is provided with a connector 313 for connecting to the top of the lower pen shell 21.

[0092] To achieve the connection between the upper pen shell 31 and the lower pen shell 21, the outer dimension of the connecting body 313 is smaller than the outer dimension of the upper shell 311, and the corresponding inner wall of the lower pen shell 21 is thinned to match the connecting body 313. Furthermore, the connecting body 313 is provided with a longitudinal clearance groove 3132, which gives the connecting body 313 elastic deformation space, making it easy to insert into the top of the lower pen shell 21. Furthermore, the connecting body 313 is provided with protruding pen shell fixing blocks 314, the number, position and size of which match the shell fixing groove 218. Furthermore, the lower part of the pen shell fixing block 314 is provided with an insertion guide slope 3142.

[0093] During the process of installing the upper pen shell pre-assembly module 3 into the lower pen shell pre-assembly module 2, the connector 313 of the upper pen shell 31 is inserted into the top of the lower pen shell 21. During the insertion process, the guide slope 3142 first contacts the top wall of the lower pen shell 21, thereby causing the wall of the connector 313 to undergo elastic deformation under force until the pen shell fixing block 314 falls completely into the housing fixing groove 218. At this time, the wall of the connector 313 elastically recovers. Furthermore, the cross-sections of the upper pen shell 31 and the lower pen shell 21 are not completely circular. After insertion, they also have positioning and limiting functions to prevent rotation between the upper pen shell 31 and the lower pen shell 21.

[0094] The upper pen shell 31 is also provided with a safety pin connecting groove 316 and a needle retraction spring base fixing groove 318, two mounting grooves; in this embodiment, the safety pin connecting groove 316 is located at the upper part, while the needle retraction spring base fixing groove 318 is located at the lower part and is located on the connecting body 313. The interior of the upper pen shell 31 is provided with several longitudinally protruding guide strips 317.

[0095] Putter 41 ,like Figure 16 , Figure 17 As shown, the device is a slender cylindrical body, including a push rod cylinder 411. The upper end of the push rod cylinder 411 is open, and the lower end is closed. The inner side of the push rod cylinder 411 is a spring cavity 412 for storing the injection spring 42. The top of the push rod cylinder 411 is provided with two or more fixing arms 413, and the space between adjacent fixing arms 413 is a clearance cavity 414. The top of the fixing arms 413 protrudes outward to form a fixing claw 415, and a retraction guide 416 is formed below the end of the fixing claw 415. In the natural state, the inner walls of the tops of the fixing arms 413 converge to form a safety pin receiving cavity.

[0096] The lower outer diameter of the push rod 411 of the push rod 41 is smaller than the inner diameter of the syringe 11, so that it can be inserted into the syringe 11 without obstruction and move along the axial direction of the syringe 11.

[0097] The bottom of the push rod cylinder 411 of the push rod 41 is provided with a piston cone 417. In this invention, the piston cone 417 of the push rod 41 not only needs to apply a downward pushing force to the piston 12 for injection, but also needs to apply an upward pulling force for needle retraction. Therefore, the piston cone 417 not only has a downward conical surface, but also has a connecting rod with a cross-section smaller than the top cross-section of the piston cone 417 between it and the push rod cylinder 411. This allows the piston cone 417 to be inserted into the piston hole 121 of the piston 12 and then be wrapped by the rubber elasticity of the piston 12, thereby being able to withstand the upward pulling force.

[0098] The lower part of the push rod cylinder 411 of the push rod 41 is provided with an outwardly protruding syringe stop 418. The syringe stop 418 has an inwardly retractable elasticity and can retract inward when subjected to force. The distance between the syringe stop 418 and the piston cone 417 matches the distance between the piston 12 and the top opening of the syringe 11 when the pre-filled syringe 1 is not in use.

[0099] During the process of the upper pen shell pre-assembly module 3 being installed into the lower pen shell pre-assembly module 2, the piston cone 417 is inserted into the top opening of the syringe 11 and finally fully inserted into the piston 12, where it is fixed. At this time, the bottom of the push rod cylinder 411 of the push rod 41 is also inserted into the top opening of the syringe 11, while the syringe stop 418 is positioned outside the top opening of the syringe 11. This prevents the syringe 11 from being subjected to impact force and moving upwards during transportation, which could cause the needle 13 to be accidentally pulled out of the protective cap 14 and result in premature injection of the medication, thus reducing the dosage.

[0100] Injection spring 42 The injection spring 42 is a slender spring, with its lower part installed inside the push rod cylinder 411 of the push rod 41, and its bottom abutting against the bottom of the push rod cylinder 411, applying a downward pushing force to the push rod 41; its upper part contacts the injection spring support 52. The elastic unfolding stroke of the injection spring 42 is relatively long, sufficient to fully push the push rod 41 into the syringe 11, so that the piston cone 417 drives the piston 12 to move along the axial direction of the syringe 11. The piston 12 moves to the bottom of the syringe 11, completely injecting the medicine into the syringe 11.

[0101] Safety pin 43 ,like Figure 18 , Figure 19 As shown, it has two movable arms 431, and the top of the movable arms 431 is provided with a connecting top. Furthermore, a guide arm 432 is provided between the two movable arms 431, and the guide arm 432 is also connected to the bottom of the connecting top; a longitudinal guide groove 433 is formed between the movable arms 431 and the guide arm 432.

[0102] The bottom of the two movable arms 431 extends downward to form mounting arms 434, which can be installed into the upper pen shell 31 along the inner wall of the upper shell 311. Furthermore, the mounting arms 434 are provided with elastic excitation claws 435, the bottom of which protrudes outward to form an excitation hook 436, which can be engaged into the safety pin connecting groove 316. The top of the excitation hook 436 has a flat fixing surface 4362 for hooking the top surface of the safety pin connecting groove 316 to fix the safety pin 43 in the upper pen shell 31. The lower part of the excitation hook 436 is provided with an inwardly inclined excitation guide 4363. Before the automatic injection pen of the present invention is used, the excitation guide 4363 extends inward beyond the safety pin connecting groove 316, protrudes inward from the upper shell 311 of the upper pen shell 31, and matches the excitation head 234 and excitation inclined surface 235 of the excitation sleeve 23 of the lower pen shell pre-assembly module 2.

[0103] The safety pin 43 has a downwardly protruding trigger pin 437 on its connecting top, the size of which matches the safety pin receiving cavity formed by the top of the fixed arm 413 of the push rod 41.

[0104] 51 retraction sleeve ,like Figure 20 , Figure 21 As shown, it is a cylinder with openings at both ends, having a sleeve body 511. The lower part of the sleeve body 511 is provided with a spring bracket fixing groove 512 for connecting and fixing the injection spring bracket 52.

[0105] The bottom of the sleeve body 511 of the retracting sleeve 51 is connected to a connecting sleeve with a smaller outer diameter, thereby forming a stepped surface at the bottom of the sleeve body 511 to abut against the top of the take-off spring 62.

[0106] The lower part of the connecting sleeve of the retractable sleeve 51 is an elastic needle retraction fixing claw 513. The bottom of the needle retraction fixing claw 513 protrudes outward to form a needle retraction fixing hook 514. The upper part of the needle retraction fixing hook 514 has an inclined needle retraction guide 515.

[0107] The needle retraction fixing claw 513 forms a push rod guide cavity inside, which matches the push rod cylinder 411. When the cylindrical tube of the push rod cylinder 411 is located in the push rod guide cavity, the needle retraction fixing claw 513 cannot retract and deform inward. When the cylindrical tube of the push rod cylinder 411 is not in the push rod guide cavity, the inner side of the needle retraction fixing claw 513 is free and can retract and deform inward.

[0108] Injection spring stent 52 ,like Figure 22As shown, it has a slender spring positioning post 521, and a narrow spring seat 522 at the top of the spring positioning post 521 for limiting the top of the injection spring 42; the two sides of the narrow spring seat 522 extend downward to form connecting arms 523, and the bottom of the connecting arms 523 is provided with a bracket hook 524 for matching and connecting with the spring bracket fixing groove 512 of the retracting sleeve 51.

[0109] like Figure 23 As shown, the push rod 41, retractable sleeve 51, and injection spring bracket 52 are assembled together to compress and fix the injection spring 42, which is the pre-use state of the automatic injection pen of the present invention; the injection spring 42 is located inside the push rod cylinder 411 of the push rod 41, and the spring positioning post 521 of the injection spring bracket 52 is inserted into the injection spring 42; the bottom of the injection spring 42 abuts against the bottom of the inner cavity of the push rod cylinder 411 of the push rod 41, applying a downward pushing force to the push rod 41, while at this time, the outer side of the fixing claw 415 of the push rod 41 rests on the top plane of the sleeve body 511 of the retractable sleeve 51, achieving a limiting position; The top of the injection spring 42 abuts against the narrow spring seat 522 of the injection spring bracket 52, applying an upward thrust to the injection spring bracket 52. At this time, the bracket hook 524 of the injection spring bracket 52 is engaged in the spring bracket fixing groove 512 of the sleeve body 511 of the retractable sleeve 51, thus achieving fixation. In the use of this invention, the bracket hook 524 is always located in the spring bracket fixing groove 512, so that the injection spring bracket 52 is always fixedly installed in the retractable sleeve 51. The position of the push rod 41 and the injection spring bracket 52 is locked by the retractable sleeve 51, thereby compressing and fixing the injection spring 42.

[0110] 61 needle take-off spring base ,like Figure 24 , Figure 25 As shown, it is a cylinder with open ends and has a spring cylinder 611. The needle take-up spring 62 is sleeved on the spring cylinder 611. The bottom of the spring cylinder 611 extends outward to form an annular spring seat 612, which is used to support the bottom of the needle take-up spring 62. The inside of the spring cylinder 611 is a connecting cavity 613, which is used to insert the connecting cylinder at the bottom of the retractable sleeve 51.

[0111] The spring seat 612 of the needle retraction spring base 61 extends further outward to form a base fixing claw 614, which is used to engage with the needle retraction spring base fixing groove 318 of the upper pen shell 31. In the use of the present invention, the base fixing claw 614 is always located in the needle retraction spring base fixing groove 318, so that the needle retraction spring base 61 is always fixed in the upper pen shell 31.

[0112] 62 needle take-off springThe spring has a relatively large outer diameter and a relatively short length. The bottom of the retractable spring 62 abuts against the spring seat 612 of the retractable spring base 61. Since the retractable spring base 61 is always fixed inside the upper pen shell 31, the bottom of the retractable spring 62 is fixed in position relative to the upper pen shell 31. The top of the retractable spring 62 abuts against the bottom plane of the sleeve body 511 of the retractable sleeve 51, applying an upward thrust to the retractable sleeve 51.

[0113] After assembly, the upper pen shell pre-assembly module 3, as follows: Figure 26 , Figure 27 As shown; the take-off spring 62 is fitted onto the take-off spring base 61, then the bottom of the sleeve body 511 of the retracting sleeve 51 abuts against the top of the take-off spring 62, moving towards the take-off spring base 61, causing the take-off fixing hook 514 to pass over the spring sleeve 611 and abut against the bottom of the spring sleeve 611, while the take-off fixing claw 513 is located inside the spring sleeve 611, compressing the take-off spring 62; then the push rod 41 is inserted, so that the lower middle part of the push rod cylinder 411 of the push rod 41 is located in the push rod guide cavity inside the take-off fixing claw 513, preventing the take-off fixing claw 513 from retracting and deforming inward. This causes the retractable sleeve 51 to disengage from the needle-retracting spring base 61 under the thrust of the needle-retracting spring 62; at this time, the fixing claw 415 at the top of the push rod 41 hooks onto the top plane of the sleeve body 511 of the retractable sleeve 51; the injection spring 42 is installed in the spring cavity 412 of the push rod 41, and then the injection spring bracket 52 is installed on top of the injection spring 42, the spring positioning post 521 is inserted into the injection spring 42, the narrow spring seat 522 abuts against the top of the injection spring 42 and compresses the injection spring 42 downward, and finally the narrow spring seat 522 is inserted into the relief cavity 414 of the push rod 41, and the connection is complete. The connecting arm 523, along with the bracket hook 524, is inserted into the sleeve body 511. The connecting arm 523 retracts and deforms inward until the bracket hook 524 is engaged in the spring bracket fixing groove 512, thus compressing and fixing the injection spring 42. Then, the safety pin 43 is installed, so that the excitation pin 437 is inserted into the safety pin receiving cavity formed by the top of the fixing arm 413 of the push rod 41, preventing the fixing arm 413 from retracting and deforming inward, and allowing the fixing claw 415 to reliably hook onto the top plane of the sleeve body 511. Finally, the entire assembly is inserted into the upper pen shell 31, and the guide strip 317 is engaged in the safety pin holder. Within the guide groove 433 of the safety pin 43, the actuation claw 435 of the safety pin 43 retracts and deforms inward until the actuation hook 436 engages with the safety pin connecting groove 316. Meanwhile, the connecting body 313 elastically deforms until the base fixing claw 614 of the needle-retracting spring base 61 engages with the needle-retracting spring base fixing groove 318 of the upper pen shell 31. At this point, both the safety pin 43 and the needle-retracting spring base 61 are fixed within the upper pen shell 31, and the positions of the various parts are relatively locked. In particular, the parts that compress and fix the injection spring 42 and the needle-retracting spring 62 are mechanically limited by other parts, achieving a safety lock. Thus, the upper pen shell pre-assembly module 3 of the present invention is formed.

[0114] The upper pen shell pre-assembly module 3 needs to be assembled with the pre-filled syringe 1 and the lower pen shell pre-assembly module 2. The connector 313 of the upper pen shell 31 is inserted into the top of the lower pen shell 21. The guide slope 3142 is compressed, causing the connector 313 to contract inwards until the pen shell fixing block 314 completely falls into the shell fixing groove 218, and the pen shell positioning strip 315 is inserted into the pen shell positioning groove 219. Simultaneously, the piston cone 417 is inserted into the piston 12. As the connector 313 is inserted, the excitation head 234, against the inner wall of the upper pen shell 31, reaches the upper pen shell pre-assembly module 3, aligning with the excitation guide 4363 of the excitation hook 436. This completes the unused state of the automatic injection pen of the present invention, ready for storage and transportation. Figure 28 As shown.

[0115] When the automatic injection pen of the present invention is delivered to the patient for use, the following steps are included:

[0116] Step 1: The patient removes the pen cap 22; as Figure 29 As shown, hold the pen body (lower pen shell 21, upper pen shell 31) with one hand and the pen cap 22 with the other hand. Apply force to remove the pen cap 22 from the lower pen shell 21. At this time, the pen cap 22 will remove the protective cap 14 along with it, so that the needle 13 inside the excitation sleeve 23 is exposed, but the needle 13 is still inside the excitation sleeve 23 and is covered by the excitation sleeve 23.

[0117] Step 2: The patient performs the injection; The patient holds the pen body and places the bottom plane of the protective ring 232 of the excitation sleeve 23 against the injection site, and then applies pressure towards the body, causing the excitation sleeve 23 to retract into the lower pen shell 21; At this time, the needle 13 gradually passes over the protective ring 232 and enters the injection site, completing the injection action.

[0118] As the excitation sleeve 23 moves upward relative to the lower pen housing 21, the excitation head 234 comes into contact with the excitation guide 4363 of the excitation hook 436. Along the inclined surface of the excitation guide 4363, the longitudinal force is converted into an inward contraction deformation force of the excitation hook 436, causing the excitation hook 436 to disengage from the safety pin connecting groove 316. Figure 30 As shown; furthermore, the excitation head 234 pushes the safety pin 43 upward, thereby causing the excitation pin 437 to disengage from the safety pin receiving cavity at the top of the push rod 41 fixed arm 413, as shown. Figure 31 As shown, the internal mechanism of the automatic injection pen of the present invention continuously realizes injection and needle retraction under the pushing force of the injection spring 42 and the needle retraction spring 62. The specific operation process is as follows:

[0119] Action 2.1: The fixed claw 415 retracts inward; as... Figure 32As shown, when the trigger pin 437 disengages from the safety pin receiving cavity at the top of the fixed arm 413, the fixed claw 415 becomes infinitely movable. Then, under the elastic unfolding force of the injection spring 42, the push rod 41 tends to move downwards. At this time, the retraction guide 416 converts the downward force of the fixed arm 413 into a force causing the fixed arm 413 to retract and deform inwards, causing the fixed claw 415 to slide along the top of the sleeve body 511 through the retraction guide 416. Figure 40 , Figure 41 As shown; finally, the fixing claw 415 completely disengages from the top plane of the sleeve body 511 and enters the interior of the sleeve body 511, causing the push rod 41 to be in a downward state under the thrust of the injection spring 42, as shown. Figure 34 As shown;

[0120] Action 2.2, During the injection process, the syringe stop 418 is compressed and squeezed into the syringe 11; as... Figure 33 As shown, after the push rod 41 moves downward a certain distance, the syringe stop 418 contacts the top of the syringe 11, and the syringe stop 418 is compressed and deformed inward until it is completely squeezed into the syringe 11, as shown. Figure 43 As shown; at this time, the push rod 41 has driven the piston 12 to move downward a certain distance, realizing the injection of the drug;

[0121] Action 2.3, during the injection process, push rod 41 pushes piston 12 to continue moving downwards; as... Figure 34 , Figure 35 , Figure 36 ,and Figure 44 As shown, the narrow spring seat 522 is located exactly in the relief cavity 414 between the fixed arms 413, which does not affect the downward movement of the push rod 41.

[0122] During the process, such as Figure 45 As shown, the clearance cavity 414 between the fixed arms 413 of the push rod 41 moves accordingly and then continuously enters the lower area of ​​the sleeve body 511, gradually approaching the inner side of the needle retraction fixing claw 513.

[0123] Action 2.4: Injection complete. The plunger 41 pushes the piston 12 to the bottom of the syringe 11, as shown. Figure 37 As shown, at this time, the fixing claw 415 of the push rod 41 also moves to the bottom of the sleeve body 511 and rests on the platform at the bottom of the sleeve body 511; while the clearance cavity 414 between the fixing arms 413 also moves to the bottom of the sleeve body 511 and is located inside the needle retraction fixing claw 513.

[0124] Action 2.5, the needle retaining claw 513 retracts inward; as... Figure 37 , Figure 46As shown, when the push rod cylinder 411 of the push rod 41 moves downward away from the position of the needle-retracting fixing claw 513, the clearance cavity 414 between the fixing arms 413 moves to the position of the needle-retracting fixing claw 513. At this time, the inside of the needle-retracting fixing claw 513 is no longer in a position of limit. Then, under the action of the needle-retracting spring 62, the top of the needle-retracting spring 62 pushes the bottom step surface of the sleeve body 511, causing the retracting sleeve 51 to tend to move upward. This causes the needle-retracting fixing claw 513 to move upward as well. The needle-retracting guide 515 on the upper part of the needle-retracting fixing hook 514 contacts the bottom of the spring seat 612, converting the upward force into the force of the needle-retracting fixing claw 513 contracting and deforming inward. This causes the needle-retracting fixing claw 513 to slide along the bottom of the spring seat 612 through the needle-retracting guide 515. Finally, the needle-retracting fixing claw 513 completely disengages from the bottom of the spring seat 612 and enters the spring cylinder 611, so that the retracting sleeve 51 is in a state of being pushed upward by the needle-retracting spring 62. Figure 38 As shown;

[0125] Action 2.6, the finishing stitch process; as follows Figure 38 As shown, the retracting spring 62 gradually unfolds, causing the retracting sleeve 51 to move upward. The bottom of the sleeve body 511 of the retracting sleeve 51 also causes the fixing claw 415 of the push rod 41 to move upward along with it. Figure 47 As shown; during this process, the piston cone 417 of the push rod 41 drives the piston 12, and the piston 12 drives the syringe 11 through friction with the bottom of the syringe 11. The syringe 11 drives the needle 13 through the connecting force, and multiple parts move upward together; as the needle 13 moves upward, it is gradually pulled out from the injection site and retracted into the excitation sleeve 23, as shown. Figure 39 As shown.

[0126] During this process, the push rod 41 will also drive the injection spring bracket 52 and the retraction sleeve 51 to move upward through the injection spring 42.

[0127] Step 3: Complete the injection and remove the needle. The patient should dispose of the automated injection pen of this invention after the injection is complete, such as... Figure 39 As shown.

[0128] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications or substitutions are all included within the scope defined by the claims of this application.

Claims

1. An automatic injection pen with a needle-retracting spring locking actuation mechanism, characterized in that, Includes push rod, retraction sleeve, needle take-up spring base, and needle take-up spring; The needle-retracting spring base is a cylinder with openings at both ends, containing a spring cylinder. The bottom of the spring cylinder extends outward to form a spring seat. The take-off spring is sleeved on the spring sleeve, and the bottom of the take-off spring abuts against the spring seat; The inside of the spring cylinder is a connecting cavity; The lower part of the retractable sleeve has a stepped surface, and the top of the take-up spring abuts against the stepped surface; A connecting sleeve is provided below the stepped surface of the retractable sleeve. The diameter of the connecting sleeve is smaller than that of the stepped surface and also smaller than that of the inner diameter of the spring sleeve. The lower part of the connecting sleeve of the retractable sleeve is an elastic needle retraction fixing claw. The bottom of the needle retraction fixing claw protrudes outward to form a needle retraction fixing hook. The upper part of the needle retraction fixing hook has an inclined needle retraction guide. The interior of the connecting cylinder and the needle retaining claw forms a push rod guide cavity; The lower part of the push rod is the push rod cylinder, which is a cylindrical tube; the push rod cylinder can slide along the axis within the push rod guide cavity; The top of the push rod cylinder has an axial clearance cavity; the clearance cavity is located in the same direction as the needle retraction fixing claw.

2. The automatic injection pen needle-retracting spring locking and actuation mechanism as described in claim 1, characterized in that, The spring seat of the needle retraction spring base extends outward to form a base fixing claw; The needle retraction spring base is fixedly installed inside the pen case via the base fixing claw; The bottom of the take-off spring is fixed to the take-off spring base, and the take-off spring can be unfolded upwards.

3. The automatic injection pen needle-retracting spring locking and actuation mechanism as described in claim 1, characterized in that, The top of the push rod extends outward to form a fixing claw, the size of which is larger than the inner diameter of the connecting sleeve of the retractable sleeve.

4. The automatic injection pen needle-retracting spring locking and actuation mechanism as described in claim 1, characterized in that, The bottom of the push rod is equipped with a piston cone, which is fixedly connected to the piston of the syringe.

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