Needle retracting spring locking excitation mechanism assembly for automatic injection pen

Abstract

The utility model relates to a narrowing spring locking excitation mechanism assembly for an automatic injection pen. The narrowing spring locking excitation mechanism assembly is formed by preassembling a narrowing spring, a narrowing spring base, a push rod and a narrowing connecting sleeve together. When the narrowing spring is in a compressed energy storage state, the narrowing spring base is combined with the narrowing connecting sleeve; the push rod is positioned in the narrowing spring base and the narrowing connecting sleeve; the push rod can slide relative to the narrowing spring base and the narrowing connecting sleeve; the middle upper part of a rod barrel of the push rod protrudes outwards to form a narrowing unlocking sheet; when the push rod slides to the maximum stroke relative to the narrowing spring base and the narrowing connecting sleeve, the narrowing spring base and the narrowing connecting sleeve are separated, the narrowing spring is unlocked, the narrowing spring is converted into an unfolded working state from a compressed energy storage state, and the narrowing spring is unfolded from the compressed state to release thrust. And the narrowing spring pushes the narrowing connecting sleeve to move. The device is reliable in structure and easy to manufacture; the reliability in the using process is high, and the unlocking action response is fast.

Description

Technical Field

[0001] The utility model relates to a locking and triggering mechanism for a needle retracting spring in an auto-injector pen, belonging to the field of medical syringes. Background Art

[0002] An auto-injector pen is a syringe product that is convenient for patients or the general public to operate; when manufacturers produce, they first fill the liquid medicine in the syringe to form a prefilled syringe (Prefilled Syringe, PFS, also known as a drug-loaded syringe,), as Figure 1 、 Figure 2 shown; then load the PFS into the auto-injector device to form an auto-injector pen for transportation and sales. After obtaining the auto-injector pen, consumers use it as needed, remove the pen cap, then press it on the injection site of the patient to trigger the injection, and finally remove the injection pen to complete the automatic injection of the liquid medicine; compared with traditional syringes, it saves the processes of sucking medicine, pricking the needle, and pushing the medicine with a disposable syringe, is more convenient to operate, and the injection dose can be guaranteed, and there will be no deviation in the injection dose due to unskilled operation.

[0003] At present, there are many auto-injector pens for PFS with a one-time fully automatic injection function on the market, which facilitates the use of patients. However, due to regulatory requirements, the needle needs to be shielded before and after use to avoid needle injury, so generally two sets of spring systems are required inside, which respectively implement the functions of pushing the medicine and shielding, so the structure of the auto-injector pen is generally more complex, which leads to the assembly of the auto-injector device with the PFS being more complex.

[0004] However, when pharmaceutical manufacturers complete the production of pharmaceuticals and fill them to form PFS, and then assemble the whole pen, they often hope to simplify the assembly process as much as possible, that is, most of the structural parts of the auto-injector device are completed at the production factory end of the auto-injector device, which can reduce the facilities and equipment for loading the PFS and improve the assembly efficiency.

[0005] Therefore, in combination with the final assembly requirements of pharmaceutical manufacturers and the safety and convenient use requirements of the terminal for auto-injector pens, it is necessary to improve the structure of auto-injector pens, especially to optimize the structure of auto-injector devices.

[0006] An auto-injector pen generally uses an injection spring for triggering and injection. However, if the operator still needs to manually remove the needle after injection, the needle is likely to be exposed, causing a safety hazard; therefore, for a fully automatic injection pen, after injection, the needle will be automatically retracted and hidden.

[0007] Therefore, a locking and triggering mechanism component for the needle retracting spring needs to be set inside the auto-injector pen to automatically trigger the needle retracting spring after injection to perform the automatic needle retracting operation. Summary of the Invention

[0008] The purpose of the present utility model is to provide a needle retraction spring locking and actuating mechanism assembly for an auto-injector pen, which can reliably compress and lock the needle retraction spring during the assembly, storage and transportation of the auto-injector pen; during the use of the auto-injector pen, it is unlocked in a timely manner as the use progresses, so that the needle retraction spring is released, thereby realizing actions such as automatic needle retraction and hidden needle.

[0009] To achieve the above-mentioned utility model purpose, the present utility model provides a needle retraction spring locking and actuating mechanism assembly for an auto-injector pen, which is pre-assembled together by a needle retraction spring, a needle retraction spring base, a push rod, and a needle retraction connection sleeve;

[0010] The needle retraction spring has a compressed energy storage state and an extended working state;

[0011] When the needle retraction spring is in the compressed energy storage state, the needle retraction spring base is combined with the needle retraction connection sleeve;

[0012] The push rod is located inside the needle retraction spring base and the needle retraction connection sleeve; the push rod can slide relative to the needle retraction spring base and the needle retraction connection sleeve;

[0013] The middle upper part of the rod barrel of the push rod bulges outwards to form a needle retraction unlocking piece;

[0014] When the push rod slides relative to the needle retraction spring base and the needle retraction connection sleeve to the maximum stroke, the needle retraction spring base and the needle retraction connection sleeve are separated, the needle retraction spring is unlocked, the needle retraction spring changes from the compressed energy storage state to the extended working state, the needle retraction spring expands from the compressed state to release thrust, and the needle retraction spring pushes the needle retraction connection sleeve to move.

[0015] As a further improvement of the present utility model, the needle retraction spring base includes a base barrel, a needle retraction spring cavity, a needle retraction spring bottom support, and a needle retraction locking part one;

[0016] The inside of the base barrel is provided with a needle retraction spring cavity for storing the needle retraction spring, and the bottom plate of the needle retraction spring cavity shrinks inwards to form a needle retraction spring bottom support for supporting the bottom of the needle retraction spring;

[0017] The needle retraction connection sleeve includes a guide barrel, a mounting flange, a needle retraction spring barrel, a needle retraction spring top support, a connection part, and a needle retraction locking part two;

[0018] The bottom of the guide barrel extends outwards to form a mounting flange, and the mounting flange is connected to the PFS mounting sleeve in the medicine cartridge pre-assembly;

[0019] Above the guide cylinder, there is a knitting needle retracting spring cylinder. The top of the knitting needle retracting spring cylinder extends outward to form a knitting needle retracting spring support. The knitting needle retracting spring is sleeved outside the knitting needle retracting spring cylinder, and the top of the knitting needle retracting spring abuts against the knitting needle retracting spring support.

[0020] At the top of the knitting needle retracting connecting sleeve, there is a connecting part. The knitting needle retracting connecting sleeve is fixed at the bottom of the injection connecting sleeve through the connecting part.

[0021] The first knitting needle retracting locking part of the knitting needle retracting spring base is clamped together with the second knitting needle retracting locking part of the knitting needle retracting connecting sleeve, so that the knitting needle retracting spring is in a compressed state.

[0022] When the knitting needle retracting unlocking piece on the rod cylinder of the push rod moves downward, it can unlock the clamping state between the first knitting needle retracting locking part and the second knitting needle retracting locking part, so that the knitting needle retracting spring is released and expanded.

[0023] Further, the first knitting needle retracting locking part of the knitting needle retracting spring base includes an elastic buckle, an elastic connecting part, a supporting surface, and a knitting needle retracting inclined surface.

[0024] At the bottom of the base cylinder, there are several elastic buckles. The elastic buckles are connected to the base cylinder through elastic connecting parts.

[0025] The bottom of the elastic buckle is a supporting surface. The supporting surface of the elastic buckle can removably support on the supporting seat of the knitting needle retracting connecting sleeve.

[0026] Inside the elastic buckle, a knitting needle retracting inclined surface is formed inward and downward.

[0027] The size of the knitting needle retracting inclined surface matches that of the knitting needle retracting unlocking piece of the push rod.

[0028] The second knitting needle retracting locking part of the knitting needle retracting connecting sleeve includes a supporting seat.

[0029] The top of the guide cylinder extends outward to form a supporting seat. Above the supporting seat, there is a knitting needle retracting spring cylinder.

[0030] The supporting surface at the bottom of the elastic buckle abuts against the supporting seat, so that the knitting needle retracting spring is in a compressed state.

[0031] The knitting needle retracting unlocking piece moves with the push rod. The knitting needle retracting unlocking piece contacts the knitting needle retracting inclined surface and presses the knitting needle retracting inclined surface downward, generating a component force that makes the elastic buckle open outward. The supporting surface of the elastic buckle disengages from the supporting seat of the knitting needle retracting connecting sleeve.

[0032] Still further, inside the guide cylinder of the knitting needle retracting connecting sleeve, there is a guide cavity. The diameter of the guide cavity matches the outer diameter of the rod cylinder of the push rod.

[0033] The guide cavity and the rod cylinder form a linear motion guide.

[0034] Furthermore, the first knitting lock part of the knitting spring base includes a locking buckle;

[0035] The locking buckle is fixed at the bottom of the base cylinder, and the bottom of the locking buckle shrinks inward to form a locking hook;

[0036] The knitting spring bottom support is arranged at intervals with the locking buckle and the locking hook;

[0037] The second knitting lock part of the knitting connection sleeve includes an elastic knitting claw;

[0038] The elastic knitting claw is located on the guide cylinder. The bottom of the elastic knitting claw is elastically connected to the cylinder wall of the guide cylinder, and the upper part of the elastic knitting claw is a claw body that can move elastically;

[0039] The middle upper part of the claw body of the elastic knitting claw bulges outward to form a locking support, and the locking support matches and corresponds to the locking hook and is connected together, so that the knitting spring is in a compressed state;

[0040] The top of the claw body of the elastic knitting claw extends inward to form an unlocking claw;

[0041] The size of the unlocking claw matches that of the knitting unlocking piece of the push rod;

[0042] The knitting unlocking piece moves with the push rod. The knitting unlocking piece contacts the unlocking claw. When the push rod moves downward, it squeezes the unlocking claw downward, so that the claw body of the elastic knitting claw deflects inward around the connection at the bottom. As a result, the locking support moves inward accordingly, so that the locking support and the locking hook gradually disengage until completely disengaged, and the knitting spring is released.

[0043] Furthermore, the end of the unlocking claw bulges upward to form a relief inclined surface.

[0044] Furthermore, a plurality of mounting ears are provided on the outer wall of the knitting spring base;

[0045] The knitting spring base is fixedly installed on the outer sleeve of the medicine cartridge pre-assembly through the mounting ears.

[0046] The knitting spring locking and actuating mechanism assembly for the automatic injection pen of the present utility model is composed of a knitting spring base, a knitting connection sleeve, and a knitting spring combined together; then, it is unlocked by the knitting unlocking piece of the push rod. By converting the downward movement of the knitting unlocking piece into the unlocking movement of the locking connection part, finally the locking connection part is completely disengaged, and the knitting spring is instantaneously released, driving the knitting connection sleeve to move upward.

[0047] The needle retraction spring locking and actuating mechanism assembly for the automatic injection pen of the present utility model realizes reliable locking of the compression energy storage state of the needle retraction spring; as the push rod for injection descends, unlocking is achieved through the needle retraction unlocking piece, and the unlocking process is simple and easy to implement; after unlocking, the needle retraction spring is instantaneously released, which can drive the needle retraction connecting sleeve to move upward to realize the actions of needle retraction and needle hiding.

[0048] The needle retraction spring locking and actuating mechanism assembly for the automatic injection pen of the present utility model has a reliable structure and is easy to manufacture; it has high reliability during use and a fast unlocking action response; moreover, the force of the needle retraction spring has nothing to do with the force of pushing the push rod, so the parameters of the needle retraction spring can be set separately according to the need for needle retraction, making the needle retraction action reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 is a schematic structural diagram of a prefilled syringe (PFS);

[0050] Figure 2 is an internal cross-sectional view of a prefilled syringe (PFS);

[0051] In the figure, 1 - prefilled syringe (PFS); 11 - syringe (sliding sleeve), 12 - syringe barrel (container, containing medicine inside), 13 - flange (also known as flange), 14 - injection needle, 15 - piston, 16 - protective cap (also known as protective sheath), 17 - shoulder;

[0052] Figure 3 is a schematic diagram of the preparation for assembling the automatic injection pen of the present utility model;

[0053] Figure 4 is a schematic diagram of the assembling process of the automatic injection pen of the present utility model;

[0054] Figure 5 is a schematic diagram of the preparation for assembling the functional pre-component;

[0055] Figure 6 is an internal cross-sectional view of the overall structure of the functional pre-component;

[0056] Figure 7 is a schematic diagram of the overall structure of the push rod of the present utility model;

[0057] Figure 8 is an overall cross-sectional view of the push rod of the present utility model;

[0058] Figure 9 is a schematic diagram of the overall structure of the needle retraction spring base of the present utility model Figure 1 ;

[0059] Figure 10 Schematic diagram of the overall structure of the knitting-needle retracting spring base of the present utility model Figure 2 ;

[0060] Figure 11 Overall sectional view of the knitting-needle retracting spring base of the present utility model;

[0061] Figure 12 Schematic diagram of the overall structure of the knitting-needle retracting connecting sleeve of the present utility model;

[0062] Figure 13 Overall sectional view of the knitting-needle retracting connecting sleeve of the present utility model;

[0063] Figure 14 Schematic diagram of the overall structure of the knitting-needle retracting spring locking and actuating mechanism (locked state);

[0064] Figure 15 Internal structure schematic diagram of the knitting-needle retracting spring locking and actuating mechanism (locked state);

[0065] Figure 16 Combined state schematic diagram of the knitting-needle retracting spring locking and actuating mechanism (locked state) and the push rod;

[0066] Figure 17 For Figure 16 Internal structure schematic diagram;

[0067] Figure 18 Internal schematic diagram of the process state of the push rod actuating the knitting-needle retracting spring locking and actuating mechanism;

[0068] Figure 19 Partial structure schematic diagram of the push rod actuating the knitting-needle retracting spring locking and actuating mechanism;

[0069] Figure 20 Schematic diagram of the overall structure of the second embodiment of the knitting-needle retracting spring base Figure 1 ;

[0070] Figure 21 Schematic diagram of the overall structure of the second embodiment of the knitting-needle retracting spring base Figure 2 ;

[0071] Figure 22 Schematic diagram of the overall structure of the second embodiment of the knitting-needle retracting connecting sleeve;

[0072] Figure 23 Internal structure schematic diagram of the second embodiment of the knitting-needle retracting connecting sleeve;

[0073] Figure 24 Half-sectional view of the second embodiment of the knitting-needle retracting connecting sleeve;

[0074] Figure 25Schematic diagram of the overall structure of the second embodiment of the retracting spring locking and actuating mechanism (locking state);

[0075] Figure 26 Schematic diagram of the combined state of the second embodiment of the retracting spring locking and actuating mechanism (locking state) and the push rod;

[0076] Figure 27 Internal schematic diagram of the process state of the push rod actuating the retracting spring locking and actuating mechanism (second embodiment). Detailed implementation manners

[0077] The following further elaborates on the detailed implementation manners of the present utility model in conjunction with the accompanying drawings.

[0078] As Figure 3 、 Figure 4 shown, the automatic injection device of the present utility model mainly includes a medicine cartridge pre-assembly 2, a function pre-assembly 3, and a top cover 4, which are delivered to the pharmaceutical manufacturer in the state of three parts of components, and then assembled with a pre-filled syringe 1. First, the pre-filled syringe 1 is loaded into the medicine cartridge pre-assembly 2 and fixed to form the state as Figure 4 shown, then the function pre-assembly 3 is loaded, and finally the top cover 4 is covered, thus forming the automatic injection pen of the present utility model.

[0079] The function pre-assembly 3, as Figure 5 、 Figure 6 shown, is mainly pre-assembled together by an injection spring sleeve 31, a safety unlocking sleeve 32, an injection connection sleeve 33, a retracting spring 34, a retracting spring base 35, an injection spring 36, a push rod 37, and a retracting connection sleeve 38.

[0080] The injection spring sleeve 31, the safety unlocking sleeve 32, and the injection connection sleeve 33 are connected to the injection spring 36 and the push rod 37 to form an injection spring locking and actuating mechanism, which mainly compresses and locks the injection spring 36 and then unlocks and actuates it; while the retracting spring 34, the retracting spring base 35, and the retracting connection sleeve 38 are connected to form a retracting spring locking and actuating mechanism, which mainly compresses and locks the retracting spring 34 and then unlocks and actuates it; the injection connection sleeve 33 is connected to the retracting connection sleeve 38 to form a support sleeve.

[0081] The present utility model provides a retracting spring locking and actuating mechanism assembly for an automatic injection pen.

[0082] For the specific structure of the push rod 37, reference can be made to Figure 7 、 Figure 8 , which includes a rod barrel 371, a spring cavity 372, a push head 373, a buckle groove 374, and a retracting unlocking piece 375. The rod barrel 371 is a thin-walled cylindrical barrel, and the internal spring cavity 372 is used to store the injection spring 36;

[0083] The middle upper part of the rod barrel 371 bulges outwards to form a stitch-receiving unlocking piece 375.

[0084] For the specific structure of the stitch-receiving spring base 35, reference can be made to Figures 9 - 11 , including a base barrel 351, a stitch-receiving spring cavity 352, a stitch-receiving spring base 353, an elastic buckle 354, an elastic connecting part 355, a support surface 356, a stitch-receiving inclined surface 357, and mounting ears 358. The base barrel 351 is a cylindrical barrel, and the internal stitch-receiving spring cavity 352 is used to store the stitch-receiving spring 34. The bottom plate of the stitch-receiving spring cavity 352 contracts inwards to form a stitch-receiving spring base 353 for supporting the bottom of the stitch-receiving spring 34; several elastic buckles 354 are provided at the bottom of the base barrel 351, and the elastic buckles 354 are connected to the base barrel 351 through the elastic connecting part 355. The elastic connecting part 355 has good elasticity, so that the elastic buckles 354 can be turned outwards by a relatively small force; the bottom of the elastic buckle 354 is the support surface 356; the inner side of the elastic buckle 354 forms a stitch-receiving inclined surface 357 inwards and downwards. The size of the stitch-receiving inclined surface 357 matches that of the stitch-receiving unlocking piece 375 of the push rod 37. When the stitch-receiving unlocking piece 375 contacts the stitch-receiving inclined surface 357 and presses down on the stitch-receiving inclined surface 357, a component force acting outwards on the elastic buckle 354 will be generated, causing the elastic buckle 354 to open outwards around the elastic connecting part 355.

[0085] The stitch-receiving spring base 35 is fixedly installed on the outer sleeve of the medicine cartridge pre-assembly 2. Therefore, several mounting ears 358 are provided on the outer wall of the stitch-receiving spring base 35. The size, quantity, and position of the mounting ears 358 match those of the outer sleeve buckle, and the mounting ears 358 are snap-fitted and installed on the outer sleeve.

[0086] For the specific structure of the stitch-receiving connecting sleeve 38, reference can be made to Figure 12 , Figure 13, including a guide cylinder 381, a guide cavity 382, a mounting flange 383, a support base 384, a needle retraction spring cylinder 385, a needle retraction spring support 386, and a connection buckle 387. The guide cylinder 381 is a cylindrical thin-walled cylinder with a guide cavity 382 inside. The diameter of the guide cavity 382 matches the outer diameter of the rod cylinder 371 of the push rod 37, so that the guide cavity 382 and the rod cylinder 371 form a linear motion guide; the bottom of the guide cylinder 381 extends outward to form a mounting flange 383. The outer diameter and thickness of the mounting flange 383 match the PFS mounting sleeve in the drug cartridge pre-assembly 2. The mounting flange 383 of the needle retraction connection sleeve 38 and the flange 13 of the encapsulation syringe 1 can be simultaneously installed in the mounting cavity formed by the flange spring claws of the PFS mounting sleeve; the top of the guide cylinder 381 extends outward to form a support base 384. Above the support base 384 is a needle retraction spring cylinder 385. The top of the needle retraction spring cylinder 385 extends outward to form a needle retraction spring support 386. The needle retraction spring 34 is sleeved outside the needle retraction spring cylinder 385, and the top of the needle retraction spring 34 abuts against the needle retraction spring support 386; preferably, a groove is provided on the wall surface of the needle retraction spring cylinder 385, so that the needle retraction spring cylinder 385 is divided into several elastic pieces.

[0087] As Figure 14 , Figure 16 shown, the needle retraction spring 34, the needle retraction spring base 35, and the needle retraction connection sleeve 38 are connected together to form a needle retraction spring locking and triggering mechanism; the needle retraction spring 34 is first placed in the needle retraction spring base 35, and then the elastic pieces of the needle retraction spring cylinder 385 of the needle retraction connection sleeve 38 contract inward, pass through the gap between the elastic buckles 354, and penetrate into the needle retraction spring cavity 352, while compressing the needle retraction spring 34, so that the needle retraction spring support 386 passes through the needle retraction spring cavity 352 and is located at the top of the compressed needle retraction spring 34; at this time, the needle retraction spring 34 is in a compressed state, and the support surface 356 of the elastic buckle 354 abuts against the support base 384, forming a locked state between the needle retraction spring base 35 and the needle retraction connection sleeve 38.

[0088] As Figures 16 - 19 shown, the needle retraction spring locking and triggering mechanism finally needs to be unlocked by the needle retraction unlocking piece 375 of the push rod 37, so as to release the needle retraction spring 34 and achieve unlocking. Specifically, the push rod 37 is driven by the injection spring 36 and moves downward. The rod cylinder 371 of the push rod 37 can be limited by the guide cavity 382 of the needle retraction connection sleeve 38 to form a linear motion; finally, as Figure 18 , Figure 19As shown in the figure, the stitch retraction unlocking piece 375 of the push rod 37 approaches the elastic buckle 354 and abuts against the stitch retraction inclined surface 357. When the push rod 37 moves downward ①, it drives the stitch retraction unlocking piece 375 to move downward synchronously ②, and then squeezes the stitch retraction inclined surface 357, causing the elastic buckle 354 to move outward ③. At this time, the elastic buckle 354 rotates around the elastic connecting portion 355, causing the supporting surface 356 to gradually leave the upper surface of the supporting seat 384 of the stitch retraction connecting sleeve 38. Since the size of the stitch retraction unlocking piece 375 is slightly larger than the size of the upper surface of the supporting seat 384, when the stitch retraction unlocking piece 375 approaches the supporting seat 384, the supporting surface 356 of the elastic buckle 354 will completely disengage from the supporting seat 384. At this time, the stitch retraction spring base 35 is fixed, and the stitch retraction spring 34 is released. The top of the stitch retraction spring 34 pushes against the stitch retraction spring support 386, driving the stitch retraction connecting sleeve 38 to move upward together.

[0089] The above-mentioned stitch retraction spring locking and actuating mechanism unlocks by means of the component of the stitch retraction unlocking piece 375 pushing the stitch retraction spring base 35; of course, it can also be designed to unlock the stitch retraction spring 34 by means of the component of the stitch retraction unlocking piece 375 driving the stitch retraction connecting sleeve 38, that is, as Figures 20 - 27 shown.

[0090] In the second embodiment of the stitch retraction spring locking and actuating mechanism, the structures of both the stitch retraction spring base 35 and the stitch retraction connecting sleeve 38 are adjusted.

[0091] The second embodiment of the stitch retraction spring base 35 is as Figure 20 、 Figure 21 shown, and includes a base cylinder 351, a stitch retraction spring cavity 352, a stitch retraction spring bottom support 353, and a locking buckle 359; the locking buckle 359 is fixed at the bottom of the base cylinder 351, and the bottom of the locking buckle 359 contracts inward to form a locking hook 3591. Since the stitch retraction spring bottom support 353 is also a structure that contracts inward, the stitch retraction spring bottom support 353, the locking buckle 359, and the locking hook 3591 are arranged at intervals. In this embodiment, there are 4 places where they are respectively partially provided.

[0092] The top of the base cylinder 351 is still provided with a mounting ear 358 for fixedly installing the stitch retraction spring base 35 on the outer sleeve of the medicine storage pre-assembly 2.

[0093] The second embodiment of the stitch retraction connecting sleeve 38 is as Figure 22 、 Figure 23 、 Figure 24As shown, it includes a guide cylinder 381, a guide cavity 382, a mounting flange 383, and an elastic needle retracting claw 388; the upper part of the elastic needle retracting claw 388 is also provided with a needle retracting spring cylinder 385, a needle retracting spring support 386, and a connecting hook 389; the elastic needle retracting claw 388 is located on the guide cylinder 381, the bottom of the elastic needle retracting claw 388 is connected to the cylinder wall of the guide cylinder 381, and the upper part of the elastic needle retracting claw 388 is an elastically movable claw body.

[0094] In the upper middle part of the claw body of the elastic needle retracting claw 388, it protrudes outward to form a locking support 3881, and the locking support 3881 is matched with the locking hook 3591 and is correspondingly arranged; the top of the claw body of the elastic needle retracting claw 388 extends inward to form an unlocking claw 3882; preferably, the end of the unlocking claw 3882 protrudes upward to form a relief inclined surface 3883.

[0095] As Figure 24 shown, when the unlocking claw 3882, especially the relief inclined surface 3883, receives a downward pressure, the elastic needle retracting claw 388 will be bent, thereby deflecting inward.

[0096] The top of the needle retracting connecting sleeve 38 can contract inward to form a connecting hook 389 for connecting with the injection connecting sleeve 33, that is, it is snapped into the connecting groove 336.

[0097] As Figure 25 shown, the needle retracting spring base 35 and the needle retracting connecting sleeve 38 are combined together to compress the needle retracting spring 34; the top of the needle retracting spring 34 still abuts against the lower part of the needle retracting spring support 386, and the bottom of the needle retracting spring 34 still abuts against the needle retracting spring base 353.

[0098] For the second embodiment of the needle retracting spring locking and actuating mechanism, it is still unlocked by the needle retracting unlocking piece 375 of the push rod 37, as Figure 26 、 Figure 27 shown; the push rod 37 moves downward ① and abuts against the unlocking claw 3882, thereby causing the claw body of the elastic needle retracting claw 388 to deflect inward around the connection at the bottom ②, so that the locking support 3881 moves inward accordingly ③, and thus the locking support 3881 and the locking hook 3591 gradually disengage; when the locking support 3881 and the locking hook 3591 are completely disengaged, the needle retracting spring 34 is instantly released, and the needle retracting spring 34 expands upward ④, thereby abutting against the needle retracting spring support 386 and driving the needle retracting connecting sleeve 38 to move upward ⑤.

[0099] In summary, the needle retraction spring locking and activation mechanism assembly of the automatic injection pen of the present utility model is composed of a combination of a needle retraction spring base 35, a needle retraction connection sleeve 38, and a needle retraction spring 34; then, it is unlocked by the needle retraction unlocking piece 375 of the push rod 37. By converting the downward movement of the needle retraction unlocking piece 375 into an unlocking movement of the locking connection part, the locking connection part is finally completely disengaged, and the needle retraction spring 34 is instantly released, driving the needle retraction connection sleeve 38 to move upward.

[0100] The preferred embodiments of the present utility model have been specifically described above. However, the present utility model is not limited to the described embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present utility model, and these equivalent modifications or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A needle retraction spring locking and activation mechanism assembly for an automatic injection pen, characterized in that: It is formed by pre-assembling a needle closing spring, a needle closing spring base, a push rod, and a needle closing connecting sleeve; The needle retracting spring has a compressed energy storage state and an expanded working state; When the needle closing spring is in a compressed energy storage state, the needle closing spring base is combined with the needle closing connecting sleeve; The push rod is located in the needle closing spring base and the needle closing connecting sleeve; the push rod can slide relative to the needle closing spring base and the needle closing connecting sleeve; The middle and upper part of the rod barrel of the push rod protrudes outward to form a needle closing unlocking piece; When the push rod slides to the maximum stroke relative to the needle closing spring base and the needle closing connecting sleeve, the needle closing spring base and the needle closing connecting sleeve are separated, the needle closing spring is unlocked, and the needle closing spring changes from a compressed energy storage state to an expanded working state. The needle closing spring expands from a compressed state to release thrust, and the needle closing spring pushes the needle closing connecting sleeve to move.

2. The needle retraction spring locking and activation mechanism assembly for an automatic injection pen according to claim 1, characterized in that: The needle closing spring base comprises a base tube, a needle closing spring cavity, a needle closing spring bottom support, and a needle closing locking part; A needle closing spring cavity for storing the needle closing spring is provided inside the base tube, and a bottom plate of the needle closing spring cavity contracts inwardly to form a needle closing spring bottom support for supporting the bottom of the needle closing spring; The needle-retracting connecting sleeve comprises a guide cylinder, a mounting flange, a needle-retracting spring cylinder, a needle-retracting spring supporting support, a connecting portion, and a second needle-retracting locking portion; The bottom of the guide cylinder extends outward to form a mounting flange, and the mounting flange is connected to the PFS mounting sleeve in the medicine chamber pre-assembly; A needle closing spring cylinder is arranged above the guide cylinder, the top of which extends outward to form a needle closing spring top support, the needle closing spring is sleeved outside the needle closing spring cylinder, and the top of the needle closing spring abuts against the needle closing spring top support; A connecting portion is provided on the top of the needle-retracting connecting sleeve, and the needle-retracting connecting sleeve is fixed to the bottom of the injection connecting sleeve through the connecting portion; The needle closing locking portion 1 of the needle closing spring base is clamped together with the needle closing locking portion 2 of the needle closing connecting sleeve, so that the needle closing spring is in a compressed state; The needle closing unlocking piece of the rod barrel of the push rod moves downward, which can unlock the clamping state of the needle closing locking part 1 and the needle closing locking part 2, so that the needle closing spring is released and unfolded.

3. The needle retraction spring locking and activation mechanism assembly for an automatic injection pen according to claim 2, characterized in that: The needle closing locking part 1 of the needle closing spring base comprises an elastic buckle, an elastic connecting part, a supporting surface, and a needle closing inclined surface; A plurality of elastic buckles are provided at the bottom of the base tube, and the elastic buckles are connected to the base tube through elastic connecting parts; The bottom of the elastic buckle is a supporting surface; the supporting surface of the elastic buckle is removably supported on the supporting seat of the needle-retracting connecting sleeve; The inner side of the elastic buckle is turned inward and downward to form a needle narrowing slope; The size of the needle narrowing bevel matches the needle narrowing unlocking piece of the push rod; The needle-retracting locking part 2 of the needle-retracting connecting sleeve comprises a supporting seat, The top of the guide cylinder extends outward to form a support seat, and a needle-retracting spring cylinder is arranged above the support seat; The supporting surface of the bottom of the elastic buckle abuts against the supporting seat, so that the needle retracting spring is in a compressed state; The needle closing unlocking piece moves with the push rod, and the needle closing unlocking piece contacts the needle closing inclined surface and presses the needle closing inclined surface downward, generating a component force that pushes the elastic buckle outward, so that the elastic buckle opens outward around the elastic connecting part, and the supporting surface of the elastic buckle disengages outward from the supporting seat of the needle closing connecting sleeve.

4. The needle retraction spring locking and activation mechanism assembly for an automatic injection pen according to claim 3, characterized in that: A guide cavity is provided inside the guide cylinder of the needle-retracting connecting sleeve, and the diameter of the guide cavity matches the outer diameter of the rod cylinder of the push rod; The guide cavity and the rod barrel form a linear motion guide.

5. The needle retraction spring locking and activation mechanism assembly for an automatic injection pen according to claim 2, characterized in that: The needle-retracting locking part 1 of the needle-retracting spring base comprises a locking buckle; The locking buckle is fixed to the bottom of the base tube, and the bottom of the locking buckle shrinks inward to form a locking hook; The needle closing spring base support, the locking buckle and the locking support hook are arranged at intervals; The second needle closing locking part of the needle closing connecting sleeve comprises an elastic needle closing claw; The elastic needle-collecting claw is located on the guide cylinder, the bottom of the elastic needle-collecting claw is elastically connected to the cylinder wall of the guide cylinder, and the upper part of the elastic needle-collecting claw is a claw body that can move elastically; The upper and middle part of the claw body of the elastic needle-retracting claw protrudes outward to form a locking card holder, and the locking card holder matches the locking hook, is correspondingly arranged, and is connected together, so that the needle-retracting spring is in a compressed state; The top of the claw body of the elastic needle-collecting claw extends inward to form an unlocking claw; The size of the unlocking claw matches the needle-reducing unlocking piece of the push rod; The needle closing unlocking piece moves with the push rod, and the needle closing unlocking piece contacts the unlocking claw. The push rod moves downward and presses the unlocking claw downward, so that the claw body of the elastic needle closing claw deflects inward around the connection at the bottom, thereby causing the locking card holder to move inward, so that the locking card holder and the locking hook are gradually separated until they are completely separated and the needle closing spring is released.

6. The needle retraction spring locking and activation mechanism assembly for an automatic injection pen according to claim 5, characterized in that: The end of the unlocking claw is protruded upward to form a yielding slope.

7. The needle retraction spring locking and activation mechanism assembly for an automatic injection pen according to claim 2, characterized in that: The outer wall of the needle-retracting spring base is provided with a plurality of mounting ears; The needle retracting spring base is fixedly mounted on the outer sleeve of the medicine bin pre-assembly through the mounting ears.

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