Automatic injection pen for pre-filled syringe

Abstract

The invention relates to an automatic injection pen for a pre-filled syringe, which comprises a pre-filled syringe PFS, the PFS is mounted in an automatic injection device, and the automatic injection device comprises an outer pen shell, an excitation unlocking sleeve, a needle retracting spring base and a syringe; the fixed part of the narrowing spring base penetrates through the excitation unlocking sleeve to be connected with the outer sleeve; the narrowing spring base is fixed in the outer sleeve; a narrowing spring is mounted on the upper part of the narrowing spring base, and a syringe is mounted on the narrowing spring base in a releasable manner; before injection, the PFS is connected with the outer sleeve through the narrowing spring base; and the needle head of the PFS penetrates through the narrowing spring base, so that the puncture part of the needle head crosses the bottom of the outer sleeve. According to the invention, the structure of the needle retracting spring base is improved, so that the needle head of the PFS can move downwards along with the outer sleeve in the needle puncturing process, and the puncturing process is more controllable and reliable.

Description

Technical Field

[0001] The invention relates to an automatic injection pen formed by installing a pre-filled syringe, belonging to the field of medical syringes. Background Art

[0002] The present invention relates to an automatic injection pen with Chinese patent publication number CN116392673A, a locking and activation mechanism and an automatic injection pen thereof with Chinese patent publication number CN219558328U, and structural improvements of related products.

[0003] In the aforementioned published Chinese patent, when the pen cap is removed, the syringe needle remains hidden within the hidden needle sleeve. The hidden needle sleeve presses against the skin at the injection site, triggering the locking mechanism and releasing the push spring. This first pushes the syringe out, allowing the needle to penetrate the injection site. The spring then continues to act, allowing the injection to proceed. In this structure, the depth to which the needle penetrates the patient's injection site is difficult to control. The hope is that when the push spring is first released, the thrust will be strong enough to fully penetrate the injection site. However, this also results in a strong puncture force from the push spring, which may cause discomfort to the patient during self-injection and lead to a loose grip, resulting in injection failure, thus posing a certain risk.

[0004] Therefore, it is necessary to make appropriate improvements to the product structure in order to improve the reliability and controllability during needle puncture and improve the safety of the automatic injection device. Summary of the Invention

[0005] The purpose of the present invention is to provide an automatic injection pen for prefilled syringes, with an improved internal structure so that during puncture, the PFS needle moves downward along with the outer sleeve to perform puncture, thereby improving the accuracy and controllability of the needle puncture; at the same time, in combination with this action, the internal structure is adjusted accordingly in order to expand the application scenarios of the automatic injection pen.

[0006] To achieve the above-mentioned object of the invention, the present invention provides an automatic injection pen for a prefilled syringe, comprising a prefilled syringe PFS, the PFS being installed in an automatic injection device;

[0007] The automatic injection device includes an outer pen housing, an activation and unlocking sleeve, a needle retraction spring base, and a syringe;

[0008] The outer pen shell includes an outer sleeve and a detachable pen cap;

[0009] An activation and unlocking sleeve is provided slidingly inside the outer sleeve;

[0010] The fixed portion of the needle-retracting spring base passes through the trigger unlocking sleeve and is connected to the outer sleeve; the needle-retracting spring base is fixed in the outer sleeve;

[0011] The upper part of the needle retraction spring base is equipped with a needle retraction spring and a releasable injection cylinder;

[0012] The injection cylinder is composed of the PFS mounting sleeve and the injection spring sleeve connected together;

[0013] An injection spring is installed inside the injection spring sleeve; a push rod is provided inside the injection spring, and a releasable structure at the top of the push rod is connected to the top of the injection spring sleeve;

[0014] The bottom of the trigger unlocking sleeve is provided with a trigger portion which can be extended beyond the bottom of the outer sleeve;

[0015] The top of the trigger unlocking sleeve is provided with an unlocking portion, which matches the release portion at the top of the push rod to unlock the injection spring;

[0016] The push rod is provided with an unlocking part, which matches the release part of the needle closing spring to unlock the needle closing spring;

[0017] The flange of the PFS is installed in the PFS mounting sleeve, and the main body of the PFS syringe passes through the PFS mounting sleeve and is inserted into the needle retraction spring base;

[0018] Before injection, the PFS is connected to the outer sleeve through the needle retraction spring base; the needle of the PFS passes through the needle retraction spring base so that the puncture part of the needle passes over the bottom of the outer sleeve.

[0019] As a further improvement of the present invention, a mounting portion is provided on the inner side of the sleeve body of the outer sleeve;

[0020] A mounting buckle is provided on the outer wall of the needle-retracting spring base;

[0021] The mounting portion of the outer sleeve is combined with the mounting buckle of the needle shrinking spring base to achieve the installation and fixation of the needle shrinking spring base in the outer sleeve.

[0022] Furthermore, the mounting portion of the outer sleeve includes a lower limit platform and an upper limit platform;

[0023] The mounting buckle of the needle-retracting spring base includes a stop block and a hook;

[0024] The abutment block abuts against the lower limit platform;

[0025] The hook is engaged with the upper limit platform;

[0026] Axial upper and lower limit fixation is achieved between the needle shrinking spring base and the outer sleeve.

[0027] Furthermore, the lower limit platform and the stop block are provided in two places, and the upper limit platform and the hook are provided in the middle;

[0028] The lower limit platforms and the stop blocks on both sides radially limit the upper limit platform and the hook in the middle.

[0029] Furthermore, an axially extending guide bar is provided above the mounting portion of the outer sleeve, and two guide bars are provided and located on both sides of the mounting portion;

[0030] A connecting buckle groove is provided on the connecting tube of the needle spring base, and the connecting buckle groove matches the guide strip to achieve radial limitation;

[0031] The mounting buckle of the needle shrinking spring base is arranged in the connecting buckle groove.

[0032] As a further improvement of the present invention, an elastic locking arm is provided on the upper part of the needle-retracting spring base, the upper part of the elastic locking arm protrudes inward to form a needle-retracting lock buckle, and the upper part of the needle-retracting lock buckle is provided with a needle-retracting triggering inclined surface;

[0033] The lower outer side of the PFS mounting sleeve is provided with a needle-reduction locking hook, which matches the needle-reduction lock buckle;

[0034] When the needle closing lock buckle and the needle closing locking hook are connected together, the needle closing spring base is connected to the PFS mounting sleeve, and the needle closing spring is in a compressed state;

[0035] The needle retraction lock buckle is disengaged from the needle retraction locking hook, and the needle retraction spring base and the PFS mounting sleeve can slide axially. The needle retraction spring is in an unlocked and excited state, which can push the syringe barrel to move axially away from the needle retraction spring base.

[0036] Furthermore, both sides of the middle portion of the push rod extend downward to form a needle-retracting unlocking portion with a free end;

[0037] The free end of the needle reduction unlocking portion matches the needle reduction excitation inclined surface of the needle reduction spring base.

[0038] As a further improvement of the present invention, before the injection spring is unlocked and activated, the push head of the push rod is inserted into the syringe or located outside the syringe, and the push head is spaced apart from the piston in the syringe;

[0039] After the injection spring is unlocked and activated, the push head contacts the piston. Under the thrust of the injection spring, the push head drives the piston to move axially in the syringe to inject the medicine.

[0040] As a further improvement of the present invention, before the needle-retracting spring is unlocked and activated, the PFS together with the PFS mounting sleeve are connected to the outer sleeve through the needle-retracting spring base;

[0041] After the needle retraction spring is unlocked and activated, the PFS installation sleeve drives the PFS to move axially upward in the outer pen shell under the thrust of the needle retraction spring, and the needle is completely retracted into the activation unlocking sleeve.

[0042] As a further improvement of the present invention, the flange of the PFS is installed in the PFS installation sleeve, the PFS installation sleeve is combined with the needle spring base, and the axial position is limited; the needle spring base is fixedly installed in the outer sleeve and axially limited;

[0043] The lower part of the needle-retracting spring base is extended outward to be provided with a plurality of positioning claws, and the lower inner side of the outer sleeve is provided with a guide body. The positioning claws of the needle-retracting spring base are in contact with the guide body of the outer sleeve to limit the axial position.

[0044] As a further improvement of the present invention, a buffer pad is provided below the flange of the PFS, and an elastic pressing member is provided above the flange of the PFS;

[0045] The bottom of the pressing piece is the pressing surface, which is annular and matches the inner circle size of the flange;

[0046] An elastic body is provided above the pressing surface, the elastic body is in a compressed state, and a top pressing surface is provided on the top of the elastic body;

[0047] The bottom surface of the injection spring sleeve is provided with a pressure surface, and the pressure surface of the injection spring sleeve is in contact with the top pressure surface of the pressing piece.

[0048] As a further improvement of the present invention, the length of the exposed end of the excitation sleeve can be adjusted according to the puncture depth and / or the length of the needle installed in the syringe.

[0049] As a further improvement of the present invention, a cap-removing tube made of thin-walled metal is provided inside the pen cap;

[0050] The inner wall of the cap-protecting tube is bulged inwards to form a plurality of cap-protecting claws.

[0051] As a further improvement of the present invention, the upper portion of the pen cap is a pen cap sleeve, which is detachably connected to the bottom of the outer sleeve; a cap removal tube is provided in the middle of the pen cap along the axial direction of the injection pen, and the cap removal tube is connected to the protective cap outside the needle;

[0052] A locking mechanism and an unlocking mechanism are provided on the inner wall of the pen cap;

[0053] The locking mechanism is that a number of locking blocks are provided on the top of the inner wall of the pen cap;

[0054] The unlocking mechanism is that a number of unlocking blocks are provided on the inner wall of the pen cap;

[0055] A cap body is also provided at the lower part of the pen cap sleeve, and a limiting claw is provided in the cap body;

[0056] A cap barrel is provided at the bottom of the outer sleeve, a limit platform is provided on the upper part of the cap barrel, and a guide inclined surface inclined axially downward is connected to the lower part of the limit platform; a guide strip arranged axially is provided on one side of the limit platform; and a clearance space is provided on the other side of the limit platform;

[0057] A recessed unlocking guide groove is provided in the middle and lower part of the cap barrel of the outer sleeve. The unlocking guide groove has an unlocking inclined surface inclined downward along the arc surface, and a guide limit surface is provided on one side of the unlocking guide groove;

[0058] A limiting protrusion is provided at the lower part of the exposed end of the excitation sleeve;

[0059] The locking block of the pen cap is located above the limit platform of the cap barrel of the outer sleeve when locked;

[0060] The unlocking block of the pen cap is located in the unlocking guide groove of the cap barrel of the outer sleeve when locked, and one or more unlocking blocks abut against the guide limit surface on one side of the unlocking guide groove, and the top of one or more unlocking blocks contacts the unlocking inclined surface of the unlocking guide groove;

[0061] The limiting claw of the pen cap is located above the limiting protrusion at the exposed end of the excitation sleeve when locked.

[0062] As a further improvement of the present invention, a top cover is provided on the top of the outer sleeve, and the top cover is fixedly connected to the top of the outer sleeve;

[0063] The upper portion of the inner side of the outer sleeve is provided with a limiting edge arranged in an arc shape along the inner wall of the cylinder cavity;

[0064] At the height of the arc of the limiting edge, the wall surface of the cylinder cavity bulges inward to form a limiting platform;

[0065] A fixing portion with a slot is provided above the lower part of the arc of the limiting edge;

[0066] The top cover comprises a cover body and a cover top; the bottom of the cover body of the top cover is symmetrically arc-shaped, forming a limiting bottom that matches the shape of the limiting edge;

[0067] The cover is arc-shaped, thereby forming two fixing parts with larger areas, and the fixing parts can be elastically deformed inwards; on the fixing parts, outward protrusions are formed to form locking hooks; the locking hooks are engaged with the card slots.

[0068] Furthermore, the wall surface at the location of the locking hook of the top cover is convex inward to form a locking platform, and an inclined locking guide surface is provided below the locking platform; and a clearance space is provided above the locking platform;

[0069] A fixed spring claw is provided on the wall surface at the top of the unlocking sleeve; the main body of the fixed spring claw is a locking hook; the top of the locking hook is connected to the top of the unlocking sleeve, and the other three sides are hollowed out to form a hollow cavity;

[0070] The bottom surface of the locking hook is a locking surface protruding outward;

[0071] After the unlocking sleeve is fully unlocked, the locking surface of the locking hook passes over the locking guide surface and reaches above the locking platform.

[0072] As a further improvement of the present invention, multiple axial motion guide structures are provided between the trigger unlocking sleeve and the outer sleeve from top to bottom, including:

[0073] A guide portion is provided at the bottom of the trigger unlocking sleeve, and a guide body is provided on the inner side of the bottom of the outer sleeve, and the guide portion is clamped between the guide bodies;

[0074] A guide protrusion is provided in the middle of the trigger unlocking sleeve, and a guide groove is provided in the axial direction on the inner upper part of the outer sleeve, and the guide protrusion is stuck in the guide groove;

[0075] An elastic arm is provided above the guide protrusion that activates the unlocking sleeve, and the spring piece of the elastic arm extends outward to form a protrusion, which is stuck in the guide groove.

[0076] Furthermore, the elastic arm that activates the unlocking sleeve is installed in the outer sleeve in a state of being compressed and deformed inwardly, and there is a positive pressure between the protrusion and the guide groove.

[0077] Furthermore, an axial motion guide structure is provided between the activation unlocking sleeve and the top cover on the top of the outer sleeve;

[0078] A long straight guide groove is provided on the top of the trigger unlocking sleeve along the axial direction, and a guide slide block is provided on the top cover, and the guide slide block is stuck in the guide groove.

[0079] Furthermore, a plurality of elastic buckles are provided downwardly in the middle of the top cover, and the lower part of the elastic buckles is provided with an outward limiting protrusion;

[0080] When the top cover is pre-assembled, the elastic buckle of the top cover is inserted between the two fixed elastic arms at the top of the push rod, and the limiting protrusion is stuck under the locking groove.

[0081] As a further improvement of the present invention, a spring upper circumferential limiter is provided on the inner side of the upper limiter of the needle shrinking spring of the PFS mounting sleeve;

[0082] A plurality of spring lower circumferential limiters are arranged on the outer ring of the needle closing spring lower limiter of the needle closing spring base.

[0083] As a further improvement of the present invention, the gap between the needle shrinking spring base and the PFS mounting sleeve is filled with buffer grease.

[0084] The automatic injection pen for prefilled syringes of the present invention improves the structure of the needle retraction spring base so that it is always fixedly connected to the outer sleeve of the outer pen shell. During the needle puncture process, the PFS needle can move downward together with the outer sleeve, and while pushing the activation and unlocking sleeve to activate and unlock it, the puncture of the injection site is completed. The puncture process is more controllable and reliable, and the patient acceptance is higher. Subsequently, the injection spring and the needle retraction spring inside the automatic injection device release the thrust respectively, realizing fully automatic drug withdrawal injection and convenient needle retraction operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0085] Figure 1 This is the overall appearance of the automatic injection pen of the present invention before use;

[0086] Figure 2 for Figure 1 Schematic diagram of the internal structure;

[0087] Figure 3 An exploded view of the components of the automatic injection pen of the present invention;

[0088] Among them, 1-PFS (Prefilled Syringe, prefilled syringe, or prefilled needle assembly, or prefilled syringe, or drug-loaded syringe), 10-drug, 11-syringe, 12-flange (or flange), 13-needle, 14-piston, 15-soft protective cap, 16-hard protective cap; 21-outer sleeve, 22-top cover, 23-pen cap; 31-activation sleeve, 32-unlocking sleeve; 4-needle retraction spring base; 51-needle retraction spring, 52-PFS installation sleeve; 61-injection spring, 62-injection spring sleeve; 7-push rod; 8-buffer pad;

[0089] Figure 4 Schematic diagram of the outer sleeve structure of the present invention;

[0090] Figure 5 Schematic diagram of the internal structure of the outer sleeve of the present invention;

[0091] Figure 6 Schematic diagram of the assembled trigger unlocking sleeve Figure 1 ;

[0092] Figure 7 Schematic diagram of the assembled trigger unlocking sleeve Figure 2 ;

[0093] Figure 8 Schematic diagram of the structure of the excitation sleeve of the present invention;

[0094] Figure 9 This is a schematic diagram of the appearance structure of the unlocking sleeve of the present invention;

[0095] Figure 10 for Figure 7 Schematic diagram of the internal structure;

[0096] Figure 11 A schematic diagram of the internal structure of the unlocking sleeve and outer sleeve combination;

[0097] Figure 12 Schematic diagram of the appearance structure of the needle reduction spring base of the present invention;

[0098] Figure 13This is a schematic diagram of the internal structure of the needle reduction spring base of the present invention;

[0099] Figure 14 This is a schematic diagram of the internal structure after the needle shrinking spring base is installed in the outer sleeve;

[0100] Figure 15 Schematic diagram of the fixing structure of the needle-reduction spring base and the outer sleeve;

[0101] Figure 16 This is a schematic diagram of the external structure of the PFS mounting sleeve and injection spring sleeve combination;

[0102] Figure 17 for Figure 16 Schematic diagram of the internal structure;

[0103] Figure 18 The outer structure of the push rod of the present invention is shown in FIG. Figure 1 ;

[0104] Figure 19 The outer structure of the push rod of the present invention is shown in FIG. Figure 2 ;

[0105] Figure 20 It is a schematic diagram of the external structure of the push rod combined with the injection spring sleeve;

[0106] Figure 21 It is a cross-sectional view of the combination of the push rod, injection spring and injection spring sleeve;

[0107] Figure 22 for Figure 21 Schematic diagram of the internal structure of the component combined with the unlocking sleeve;

[0108] Figure 23 for Figure 22 Overall cross-sectional view;

[0109] Figure 24 This is a schematic structural diagram of step 1 of using the automatic injection pen of the present invention;

[0110] Figure 25 This is a schematic structural diagram of step 2 of using the automatic injection pen of the present invention;

[0111] Figure 26 for Figure 25 Overall cross-sectional view;

[0112] Figure 27 This is a schematic diagram of the action structure of activating and unlocking the injection spring in step 2 of using the automatic injection pen of the present invention;

[0113] Figure 28 This is a schematic structural diagram of step three of using the automatic injection pen of the present invention;

[0114] Figure 29 for Figure 28 Overall cross-sectional view;

[0115] Figure 30 This is a schematic diagram of the action structure of unlocking the needle-retracting spring in step three of using the automatic injection pen of the present invention;

[0116] Figure 31 This is a schematic structural diagram of step four of using the automatic injection pen of the present invention;

[0117] Figure 32 for Figure 31 Overall cross-sectional view.

[0118] Figure 33 This is the installation diagram of PFS;

[0119] Figure 34 This is the internal cross-sectional view after PFS installation;

[0120] Figure 35 It is the lower axial positioning structure of the needle-retracting spring base;

[0121] Figure 36 A comparison chart of PFS of different flanges;

[0122] Figure 37 Schematic diagram of the overall structure of the cushion;

[0123] Figure 38 Schematic diagram of the inner structure of the PFS mounting sleeve;

[0124] Figure 39 This is a schematic diagram of the installation of the buffer pad in the PFS mounting sleeve;

[0125] Figure 40 This is the appearance of the buffer pad after installation in the PFS installation sleeve;

[0126] Figure 41 for Figure 40 Cross-sectional view of the internal structure of the state;

[0127] Figure 42 Schematic diagram of the overall structure of the pressing part Figure 1 ;

[0128] Figure 43 Schematic diagram of the overall structure of the pressing part Figure 2 ;

[0129] Figure 44 It is a structural diagram of the combination of the pressing member and the injection spring sleeve;

[0130] Figure 45 It is a schematic diagram of the overall structure of the small flange PFS combined with the buffer pad and the pressing piece;

[0131] Figure 46 This is a schematic diagram of the overall structure of the large flange PFS combined with the buffer pad and the pressing piece;

[0132] Figure 47 This is a schematic diagram of the installation of the large flange PFS in the PFS installation sleeve;

[0133] Figure 48 This is a schematic diagram of the internal structure of PFS installed through buffer pads and compression parts;

[0134] Figure 49 for Figure 48 A partial enlarged schematic diagram;

[0135] Figure 50 Comparison of auto-injection pens with different puncture depths;

[0136] Figure 51 To compare the excitation sleeves adapted to different puncture depths;

[0137] Figure 52 for Figure 50 A partial enlarged schematic diagram;

[0138] Figure 53 This is a comparison of the use of auto-injection pens with different puncture depths in step 1;

[0139] Figure 54 This is a comparison of the auto-injection pen at different puncture depths at the end of step 4.

[0140] Figure 55 for Figure 54 A partial enlarged schematic diagram;

[0141] Figure 56 This is a structural comparison of different needle lengths and puncture depths.

[0142] Figure 57 This is a schematic diagram of the structure of a pen cap that uses a metal cap-protecting tube;

[0143] Figure 58 It is a structural diagram of a metal cap-retaining tube;

[0144] Figure 59 This is a schematic diagram of the overall structure of a plastic injection-molded pen cap;

[0145] Figure 60 Schematic diagram of the bottom structure of the pen cap;

[0146] Figure 61 This is a schematic diagram of the overall structure of a pen cap that uses a metal cap-protecting tube;

[0147] Figure 62 for Figure 61 Schematic diagram of the internal structure;

[0148] Figure 63 This is a schematic diagram of the pen cap after the protective cap tube is removed;

[0149] Figure 64 Schematic diagram of the fixing and unlocking structure (activation sleeve and lower part of outer sleeve) connected to the pen cap;

[0150] Figure 65 Schematic diagram of the combined structure of the pen cap and the connecting structure;

[0151] Figure 66 A schematic diagram of unlocking the pen cap and the connecting structure;

[0152] Figure 67 This is a schematic diagram of the structure of the pen cap sealing and fixing the end of the automatic injection pen;

[0153] Figure 68 Schematic diagram of the structure of the upper part of the outer sleeve;

[0154] Figure 69 Schematic diagram of the overall structure of the top cover Figure 1 ;

[0155] Figure 70 Schematic diagram of the overall structure of the top cover Figure 2 ;

[0156] Figure 71 It is a schematic cross-sectional view of the local structure of the top cover;

[0157] Figure 72 A schematic diagram of the structure for sealing and assembling the outer sleeve with the top cover;

[0158] Figure 73 for Figure 72 Schematic diagram of the local structure cutaway state Figure 1 ;

[0159] Figure 74 for Figure 72 Schematic diagram of the local structure cutaway state Figure 2 ;

[0160] Figure 75 A schematic diagram of the overall structure of the unlocking excitation sleeve;

[0161] Figure 76 for Figure 75 Schematic diagram of the local structure cutaway Figure 1 ;

[0162] Figure 77 for Figure 75 Schematic diagram of the local structure cutaway Figure 2 ;

[0163] Figure 78 A schematic diagram of the structure for locking the top cover and the unlocking trigger sleeve;

[0164] Figure 79 A schematic cross-section of the local structure showing the unlocking of the trigger sleeve locked in the outer sleeve assembly Figure 1 ;

[0165] Figure 80 A schematic cross-section of the local structure showing the unlocking of the trigger sleeve locked in the outer sleeve assembly Figure 2 ;

[0166] Figure 81 Schematic diagram of the distribution of the axial motion guide structure provided for unlocking the excitation sleeve;

[0167] Figure 82 A schematic diagram of the axial motion guide structure for unlocking the lower portion of the excitation sleeve;

[0168] Figure 83 A schematic diagram of the axial motion guide structure of the middle portion of the unlocking excitation sleeve;

[0169] Figure 84 A schematic diagram of the axial motion guide structure for unlocking the upper portion of the excitation sleeve;

[0170] Figure 85 Schematic diagram of the internal structure of the top cover;

[0171] Figure 86 A schematic diagram of the structure for guiding the axial movement of the top cover and the top structure of the unlocking trigger sleeve;

[0172] Figure 87 Schematic diagram of the overall structure for pre-assembly of the top cover and the unlocking trigger sleeve;

[0173] Figure 88 for Figure 87 Schematic diagram of the internal structure;

[0174] Figure 89 for Figure 87 A main sectional view in one direction;

[0175] Figure 90 for Figure 87 A main sectional view in another direction;

[0176] Figure 91 This is a schematic diagram of the structure of the upper limit position of the needle spring in the PFS installation sleeve;

[0177] Figure 92 This is a schematic diagram of the structure of the lower limit position of the needle closing spring in the needle closing spring base;

[0178] Figure 93It is a structural diagram of the needle-retracting spring part. DETAILED DESCRIPTION

[0179] The specific embodiments of the present invention are further described in detail below with reference to the accompanying drawings.

[0180] The present invention relates to an automatic injection pen for prefilled syringes, the overall structure of which is as follows Figure 1 、 Figure 2 、 Figure 3 As shown, it includes a PFS for containing medicines and an automatic injection device installed and using the PFS. The automatic injection device is composed of an outer sleeve 21 and a top cover 22 combined together to form a pen barrel for installing internal components and for the operator to hold; a pen cap 23 is detachably connected to the lower part of the outer sleeve 21, and the pen cap 23 is used to seal the pen barrel during storage and transportation; an activation and unlocking sleeve formed by combining an activation sleeve 31 and an unlocking sleeve 32 is slidably provided inside the outer sleeve 21; the lower part of the outer sleeve 21 is fixedly mounted A needle-retracting spring base 4 is installed (in the above-mentioned prior art, the lower spring sleeve (8) is slidably installed in the pen barrel body (21)); a needle-retracting spring 51 is installed on the upper part of the needle-retracting spring base 4, and a PFS mounting sleeve 52 is releasably installed; an injection spring sleeve 62 is connected and installed on the upper part of the PFS mounting sleeve 52; an injection spring 61 is installed on the upper part of the injection spring sleeve 62; a push rod 7 is sleeved inside the injection spring 61, and the top of the push rod 7 is releasably connected to the top of the injection spring sleeve 62.

[0181] The automatic injection pen for prefilled syringes of the present invention is installed with a PFS1 in a PFS mounting sleeve 52, in particular, the main body of the syringe 11 is passed through the PFS mounting sleeve 52 and extended into the needle retraction spring base 4; the puncture end of the needle 13 connected to the bottom of the syringe 11 passes through the bottom of the outer sleeve 21 and enters the excitation end of the excitation sleeve 31 (in the above-mentioned prior art, the needle (12) is located in the pen barrel main body (21) and the hidden needle sleeve (3) before the whole is excited and unlocked); the protective cap wrapped around the needle 13, generally including a soft protective cap 15 and a hard protective cap 16, is inserted into the pen cap 23 and combined with the pen cap 23; the flange 12 is fixedly mounted in the PFS mounting sleeve 52 by a buffer pad 8; at the same time, the push head end of the push rod 7 enters the syringe 11 and approaches the piston 14 (in the above-mentioned prior art, the end of the piston assembly (4) is always connected to the piston (111)).

[0182] The outer sleeve 21 has a specific structure as follows Figure 4 、 Figure 5As shown, a sleeve body 211 with openings at both ends has a sleeve cavity 212 inside; a fixing portion 213 is provided at the top of the sleeve body 211 for fixedly connecting with the top cover 22; a pen cap connecting portion 214 is provided at the bottom of the sleeve body 211 for connecting or unlocking the pen cap 23; a guide body 215 and a guide groove 2152 are axially provided on the inner side of the sleeve body 211, that is, on the wall surface of the sleeve cavity 212, to guide the axial movement of the trigger unlocking sleeve in the outer sleeve 21, the guide body 215 is located at the lower part, and the guide groove 2152 is located at the upper part, realizing axial movement guidance at the upper and lower parts; a mounting portion is provided at the middle and lower part of the inner side of the sleeve body 211, including a lower limit platform 216 and an upper limit platform 217, for connecting and fixing with the needle spring base 4; at the same time, an axially extending guide strip 218 is also provided above the mounting portion.

[0183] Stimulate the unlocking sleeve, the specific structure is as follows Figure 6 、 Figure 7 、 Figure 10 As shown;

[0184] Excitation sleeve 31, please refer to Figure 8 The bottom is an excitation surface 311, which is used to press against the skin of the injection site; the middle of the excitation surface 311 is a puncture hole 312, for the puncture end of the needle 13 to pass through and pierce the skin of the injection site; the lower part of the excitation sleeve 31 is provided with a guide part 313, which is adapted to the guide body 215 to guide the axial movement of the lower part; the upper part of the excitation sleeve 31 is provided with an opening 314 for other components to pass through; the top of the excitation sleeve 31 is provided with a fixing part 315; the upper outer wall surface of the excitation sleeve 31 is provided with a guide protrusion 316, which is adapted to the guide groove 2152 to guide the axial movement of the upper part.

[0185] Unlocking sleeve 32, please refer to Figure 9 An unlocking plate 321 is provided on the inner side of the upper part, and an unlocking inclined surface 322 is provided on the unlocking plate 321; a safety plug-in plate 323 is provided in the middle of the unlocking plates 321 on both sides, and a safety protrusion 324 is provided on the top of the safety plug-in plate 323; a fixing portion 325 is provided at the bottom of the unlocking sleeve 32, and the fixing portion 315 of the excitation sleeve 31 is combined with the fixing portion 325 of the unlocking sleeve 32 to realize the combination of the excitation sleeve 31 and the unlocking sleeve 32 to form an integrated excitation unlocking sleeve; further, a fixing claw 326 is provided at the top of the unlocking sleeve 32.

[0186] like Figure 11 As shown, the activation unlocking sleeve is installed in the outer sleeve 21, the guide portion 313 is adapted to the guide body 215, and the guide protrusion 316 is inserted into the guide groove 2152, so that the activation unlocking sleeve can move axially along the outer sleeve 21.

[0187] The needle spring base 4, the specific structure is as shown in 12, Figure 13 As shown, the lower middle portion is a hollow guide cylinder 41; the bottom of the guide cylinder 41 protrudes inward, forming an elastic limiting claw 412, which is used to position and cushion the bottom of the syringe 11; the bottom of the guide cylinder 31 protrudes outward, forming a positioning claw 413. Preferably, there are four positioning claws 413, which respectively contact the guide body 215 of the outer sleeve 21 to achieve positioning. The upper portion of the guide cylinder 41 forms a connecting structure, including a needle spring lower limit 414 formed at the top of the guide cylinder 41. The PFS mounting sleeve coupling cavity 42 is provided outside the lower limit 414 of the needle spring, and a connecting cylinder 43 is provided on the outer side. The connecting cylinder 43 is symmetrically provided with connecting snap grooves 45, which match the guide bar 218 to achieve radial limiting. A mounting buckle is provided on the lower inner portion of the connecting buckle slot 45, which engages with the mounting portion within the outer sleeve 21 to securely mount the needle-reduction spring base 4 within the outer sleeve 21. The buckle includes a stopper 442 that abuts the lower limit plate 216, and a hook 441 that engages the upper limit plate 217, thereby securing the needle-reduction spring base 4 in the axial direction. A lock that can be opened from the inside out is also provided on the upper inner portion of the connecting buckle slot 45. The lock includes an elastic locking arm 46 that is slightly inwardly inclined in its natural state. The upper portion of the elastic locking arm 46 protrudes inward to form a needle-reduction lock buckle 47. The upper portion of the needle-reduction lock buckle 47 is provided with a needle-reduction activation slope 48.

[0188] like Figure 14 、 Figure 15 As shown, the needle-retracting spring base 4 is combined with the mounting portion of the outer sleeve 21 through a mounting buckle to achieve fixed installation.

[0189] The PFS mounting sleeve 52 and the injection spring sleeve 62 can be combined together to form a mounting cavity for mounting the injection spring 61 and the push rod 7. Figure 16 、 Figure 17 shown.

[0190] The lower portion of the PFS mounting sleeve 52 is a guide tube 521, which can be inserted into the PFS mounting sleeve coupling cavity 42 of the needle spring base 4. The guide tube 521 is provided with a needle-retracting sliding surface 5212 and a needle-retracting locking hook 5213. The top of the guide tube 521 extends inward, forming an upper limit 522 for the needle-retracting spring. A platform is formed on the top of the guide tube 521, namely the PFS fixing platform 523. Above the PFS fixing platform 523 is an inwardly extending PFS fixing claw 524. The PFS fixing platform 523 and the PFS fixing claw 524 combine to limit and fix the flange 12 of the PFS in the upper and lower positions, thereby achieving the fixation of the PFS 1. The upper portion of the PFS mounting sleeve 52 is provided with a connecting portion, including a connecting groove 527 and a limiting surface 528, for fixed connection with the injection spring sleeve 62.

[0191] The top of the injection spring sleeve 62 is located in a through-hole for the top of the push rod 7 to pass through. An injection spring upper limit 622 is located below the top of the injection spring sleeve 62. Inside the through-hole at the top of the injection spring sleeve 62, a push rod fixing bracket 623 and an anti-rotation groove 624 are provided for connecting to and preventing the top of the push rod 7. The lower portion of the injection spring sleeve 62 is provided with an axial slot, namely a guide groove 626. The lower portion of the injection spring sleeve 62 is provided with a connecting portion, including a connecting hook 627 and a limit plate 628, which respectively mate with the connecting groove 527 and limit surface 528 of the PFS mounting sleeve 52 to achieve a fixed connection.

[0192] Push rod 7, the specific structure is as follows Figure 18 、 Figure 19 As shown; the lower part of the push rod 7 is the push rod portion 71, and the bottom of the push rod portion 71 is the push head 72; the upper part of the push rod 7 is provided with two fixed elastic arms 73 that can be elastically deformed inward, and the bottom of the fixed elastic arm 73 extends outward to form a lower limit 733 of the injection spring. The upper portion of the fixed elastic arm 73 is provided with a fixing structure and an unlocking structure. The fixing structure is a locking groove 74, with a locking hook 742 formed at the top of the locking groove 74, which mates with the push rod fixing bracket 623. An anti-rotation latch 75 is provided between the two locking grooves 74, which mates with the anti-rotation groove 624. A safety groove is formed in the middle of the top of the two fixed elastic arms 73 to accommodate the safety plug plate 323. Furthermore, the inner side of the top of the two fixed elastic arms 73 forms a safety cone groove 76. The safety cone groove 76 is tapered, narrow at the top and wide at the bottom, to accommodate the safety protrusion 324. When the safety protrusion 324 attempts to move upward, it is squeezed by the safety cone groove 76, generating greater force, making it difficult to disengage, thereby improving safety. Unlocking heads 77 are provided on both sides of the top of each fixed elastic arm 73, which mate with the unlocking slope 322 on the unlocking plate 321. The middle part of the push rod 7, that is, the lower part of the lower limit 733 of the injection spring, extends downward on both sides to form a needle-retracting unlocking part 78. The needle-retracting unlocking part 78 is simultaneously stuck in the guide groove 626 to guide the axial movement of the push rod 7; the bottom plate of the needle unlocking part 78 preferably forms an unlocking inclined surface 782, which contacts the needle-retracting excitation inclined surface 48 to achieve unlocking.

[0193] like Figure 20 、 Figure 21 As shown, this is a structural schematic diagram of the push rod 7 and the injection spring 61 installed in the injection spring sleeve 62, wherein the locking hook 742 is engaged with the push rod fixing bracket 623, and the anti-rotation card 75 is engaged with the anti-rotation groove 624; the injection spring 61 is in a compressed state, with the top resting on the upper limit 622 of the injection spring and the bottom resting on the lower limit 733 of the injection spring; the needle retraction unlocking portion 78 is located in the guide groove 626; the push rod portion 71 extends downward and exceeds the injection spring sleeve 62.

[0194] Further, if Figure 22 、 Figure 23As shown, it is combined with the unlocking sleeve 32; the safety plug plate 323 is inserted into the safety groove in the middle of the top of the two fixed elastic arms 73, especially the safety protrusion 324 is inserted into the safety cone groove 76, so that the two fixed elastic arms 73 cannot be elastically deformed inward, that is, they cannot be separated from the injection spring sleeve 62, thereby making the injection spring 61 always in a compressed state; the unlocking inclined surface 322 of the unlocking plate 321 is located below the unlocking head 77.

[0195] The automatic injection pen for prefilled syringes of the present invention is assembled as follows Figure 1 、 Figure 2 As shown, the activation and unlocking sleeves (activation sleeve 31 and unlocking sleeve 32) are located at the bottom, the pen cap 23 is installed in place, and the entire automatic injection pen is in a safe and closed state and can be transported and stored.

[0196] The prefilled syringe automatic injection pen of the present invention comprises the following steps when used:

[0197] Step 1: Pull out the pen cap 23. Figure 24 As shown; the operator holds the outer sleeve 21 in one hand and the pen cap 23 in the other hand, and removes the pen cap 23 from the outer sleeve 21 by first rotating and then pulling; when the pen cap 23 is pulled off, the protective caps (soft protective cap 15, hard protective cap 16) wrapped around the needle 13 are also pulled off, so that the needle 13 is in a puncture-ready state; at this time, the lower part of the trigger sleeve 31 extends beyond the outer sleeve 21 and wraps the puncture end of the needle 13, and is in a state ready for triggering.

[0198] Step 2: Wear stimulating hair, such as Figure 25 , Figure 26 As shown, the operator holds the main body of the automatic injection pen after removing the pen cap 23 in step 1 with one hand, presses the activation surface 311 of the activation sleeve 31 against the skin of the patient's injection site, and then applies a downward force, so that the outer sleeve 21 drives the internal components connected thereto to move downward together; from the perspective of the automatic injection pen, the activation sleeve 31 moves upward relative to the outer sleeve 21; during this process, the needle 13 passes through the puncture hole 312, passes over the activation surface 311, and pierces the injection site.

[0199] Compared with the prior art (the applicant's prior application, the automatic injection pen with Chinese patent publication number CN116392673A), the PFS1 where the needle 13 is located is installed in the PFS mounting sleeve 52, and is now engaged with the needle retraction spring base 4, and the needle retraction spring base 4 is fixed in the outer sleeve 21. Therefore, as the outer sleeve 21 is pressed downward, the needle 13 also moves downward, and the depth to which the needle 13 can penetrate the injection site beyond the excitation surface 311 is also controllable. Therefore, the automatic injection pen for prefilled syringes of the present invention can ensure that the same puncture depth can be obtained each time during puncture, reaching the set depth of drug injection, which is more reliable; and the puncture process is manually performed by the operator, the process is more controllable, and the patient acceptance is better.

[0200] In this step, in addition to completing the puncture, as the excitation sleeve 31 moves upward relative to the outer sleeve 21, the unlocking sleeve 32 also moves upward relative to the outer sleeve 21 to excite. Figure 27 :

[0201] (1) The safety protrusion 324 is forced out of the safety cone groove 76;

[0202] (2) The safety plate 323 is removed from the safety slot between the two fixed elastic arms 73;

[0203] (3) As the unlocking head 77 moves downward, it contacts the unlocking inclined surface 322 of the unlocking plate 321. Guided by the unlocking inclined surface 322, the unlocking head 77 drives the two fixed elastic arms 73 to deform inward. Subsequently, the lock hook 742 of the locking groove 74 disengages from the push rod fixed support 623, and the anti-rotation clip 75 disengages from the anti-rotation groove 624.

[0204] (4) Until the two fixed elastic arms 73 are fully deformed inward, the locking groove 74 and the anti-rotation clip 75 at the top are completely disengaged from the push rod fixing bracket 623 and the anti-rotation groove 624 at the top of the injection spring sleeve 62, that is, the top of the push rod 7 is disengaged from the top of the injection spring sleeve 62; at this point, the injection spring 61 is unlocked and is in a releasable state;

[0205] (5) The fixed spring claw 326 at the top of the unlocking sleeve 32 passes over the fixed inner claw 224 of the top cover 22 (the fixed outer claw 222 of the top cover 22 is combined with the fixed portion 213 / fixing groove of the outer sleeve 21 to achieve the fixation between the top cover 22 and the outer sleeve 21), so that the unlocking sleeve 32 and the triggering sleeve 31 are stopped and fixed at the upper limit position in the outer sleeve 21 after completing the unlocking and triggering actions.

[0206] After the injection spring 61 is unlocked, it is released outwards, pushing the push rod 7, and then entering step three.

[0207] Step 3: Injection Figure 28 、 Figure 29 As shown; the injection spring 61 is unfolded and released, and the top of the injection spring 61 is fixed by the injection spring upper limit 622 of the injection spring sleeve 62, while the bottom of the injection spring 61 pushes the injection spring lower limit 733 of the push rod 7, causing the push rod 7 to move downward; the push head 72 at the bottom of the push rod 7 contacts the piston 14 in the PFS1, thereby pushing the piston 14 to move axially in the syringe 11, and injecting the medicine 10 in the syringe 11 out of the needle 13 and into the patient's body.

[0208] During the downward movement of the push rod 7, the needle-retraction unlocking parts 78 on both sides move downward accordingly. When the piston 14 is about to reach the bottom of the inner tube of the syringe 11, the unlocking inclined surface 782 of the needle-retraction unlocking part 78 contacts the needle-retraction triggering inclined surface 48; the push rod 7 continues to move downward, and the needle-retraction unlocking part 78 opens the needle-retraction triggering inclined surface 48 outward, so that the needle-retraction lock buckle 47 gradually disengages from the needle-retraction locking hook 5213.

[0209] Until the piston 14 reaches the bottom of the inner tube of the syringe 11, the medicine 10 in the syringe 11 is completely injected, the needle lock 47 is completely disengaged from the needle locking hook 5213, so that the needle spring 51 between the PFS mounting sleeve 52 and the needle spring base 4 is unlocked and is in a releasable state. Figure 30 As shown, then, go to step four.

[0210] Step 4: Close the needle. Figure 31 、 Figure 32 As shown; since the needle withdrawal spring base 4 is fixed in the outer sleeve 21, the bottom of the needle withdrawal spring 51 is against the needle withdrawal spring lower limit 414 of the needle withdrawal spring base 4, and the top of the needle withdrawal spring 51 pushes the needle withdrawal spring upper limit 522, thereby driving the PFS mounting sleeve 52 to move upward; the PFS mounting sleeve 52 then drives the buffer pad 8 and PFS1 connected thereto to move upward together, and the upward movement of PFS1 drives the needle 13 to move upward, so that the needle 13 is pulled out from the injection site; at the same time, the PFS mounting sleeve 52 drives the injection spring sleeve 62 and the injection spring 61 and push rod 7 located inside the two to move upward together.

[0211] Until the top of the injection spring sleeve 62 is pressed against the top of the unlocking sleeve 32 to achieve positioning, at which time the needle 13 retreats from the puncture hole 312 and retracts into the lower part of the excitation sleeve 31, or even retracts into the lower part of the outer sleeve, away from the excitation surface 311, meeting safety standards and achieving a safety protection effect.

[0212] The above content has disclosed the essential technical features of the automatic injection pen for prefilled syringes of the present invention. Furthermore, the automatic injection pen for prefilled syringes of the present invention has the following structural improvements.

[0213] 1. Improve the installation stability of PFS1 so that the position of PFS1 relative to the outer sleeve 21 can be stable during the above steps 2 and 3.

[0214] like Figure 33 、 Figure 34 、 Figure 35 As shown, the upper portion of the PFS1, the flange 12 is mounted in the PFS mounting sleeve 52, and the PFS mounting sleeve 52 is mounted by combining the needle lock buckle 47 with the needle locking hook 5213, and the mounting portion 44 of the needle spring base 4 is elastically connected to the upper limit platform 217 of the outer sleeve 21, and each connection is elastically connected in the diameter direction, thereby making the PFS1 at the flange 12 and the outer sleeve 21 almost concentric and coaxial. In the middle and lower portion of the PFS1, the syringe 11 is sleeved in the guide cylinder 41 of the needle spring base 4, and there is almost no gap between the two, and the upper portion of the needle spring base 4 is directly connected to the outer sleeve 21 to achieve positioning. At the same time, the lower portion of the needle spring base 4 contacts the guide body 215 of the outer sleeve 21 at multiple locations (four locations in this embodiment) through the positioning claws 413, thereby making the guide cylinder 41 of the needle spring base 4 almost concentric and coaxial with the outer sleeve 21. Furthermore, the shoulder of the syringe 11 of the PFS1 (i.e. Figure 43 、 Figure 44 The bottom of the syringe 11 is supported by the inwardly extending elastic retaining claws 412, which position it in the diameter direction, ensuring that the bottom of the syringe 11 is also nearly concentric and coaxial with the outer sleeve 21. Ultimately, the syringe 11 of the PFS1 is nearly concentric and coaxial with the outer sleeve 21 from top to bottom, ensuring that the needle 13 of the PFS1 is nearly coaxial with the outer sleeve 21.

[0215] Furthermore, when the flange 12 of PFS1 is installed into the PFS installation sleeve 52, a buffer pad 8 is provided below, and the upper portion is limited by the pressing member 9, as shown in FIG. Figure 44 As shown, the pressing member 9 is an elastic member, and the bottom of the pressing member 9 is a circular pressing surface 91, which is completely pressed on the flange 12, so that the flange 12 is evenly pressed in the circumferential direction; the top of the pressing surface 91 is a hollow elastic body 92, and the top of the elastic body 92 does not press the pressing surface 94, but is pressed and limited by the bottom of the injection spring sleeve 62. Figure 44In the installation state shown, the elastomer 92 is compressed and deformed, so that a certain pressure can be applied to the flange 12 through the pressing surface 91, so that the axial direction of the syringe 11 of PFS1 is downward, that is, the flange 12 can be pressed against the buffer pad 8 to maintain flat fit, and the shoulder of the syringe 11 can always be pressed against the elastic limiting claw 412 to support and limit it, and further the syringe 11 is coaxial with the outer sleeve 21, thereby ensuring that the needle 13 is coaxial with the outer sleeve 21; it is intended to improve the puncture process of the needle 13 in step two, to ensure that there is no swinging or deviation, to ensure the smooth progress of the needle puncture, the accuracy of the needle insertion position can also improve the patient's comfort, and at the same time, it can improve the vertical displacement of the needle 13 in the direction of the needle insertion depth under the influence of the impact force of the injection spring 61.

[0216] 2. Anti-tampering.

[0217] like Figure 33 As shown, at the bottom of the guide cylinder 41 of the needle retraction spring base 4, it extends outward to form at least two wings 416; the bottom of the wing 416 is a cantilever, which contracts inward, and the inner diameter in the natural state is smaller than the outer diameter of the outer protective cap of the needle 13, especially the outer diameter of the hard protective cap 16.

[0218] During PFS1 installation, the syringe 11 is pre-installed with the protective cap. The cap pushes the flaps 416 outward from the top, causing them to elastically deform. Space for the flaps 416 is required at the connection point between the cap 23 and the protective cap, or the cap 23 requires a tool to further open the flaps 416 to facilitate installation. If the cap 23 of the autoinjector is accidentally removed, the protective cap separates from the needle 13, exposing the needle 13 and potentially contaminating the medication 10 in the syringe 11. Alternatively, the reverse injection of hazardous substances through the needle 13 could occur. However, with this design, once the protective cap is removed, several flaps 416 automatically retract inward, creating a smaller space. At this point, attempting to re-insert the cap is prevented from properly passing through the ends of the flaps 416.

[0219] Therefore, the automatic injection pen of the present invention has an anti-tampering function.

[0220] 3. Two specifications of flanges 12 adapted to PFS1.

[0221] The flange 12 of PFS1 is generally circular or non-circular, such as Figure 36 As shown, the small flange 121 and the large flange 122; Figure 36 As can be seen from the comparison of the top view below, the large flange 122 can completely accommodate the small flange 121 (the dotted line in the figure shows the outer dimensions of the small flange 121).

[0222] The above description has described the method of installing PFS1 into the installation accommodating cavity in the PFS installation sleeve 52 through the flange 12; however, when replacing the flange, it is generally necessary to replace the PFS installation sleeve 52. The reason is that in the above design, the cylinder of the syringe 11 of PFS1 passes through the hollow in the middle of the installation accommodating cavity in the PFS installation sleeve 52, and the flange 12 is placed on the PFS fixing platform 523. Then, the PFS fixing claw 524 elastically resets and clamps the top of the flange 12, thereby realizing the installation and fixation of PFS1 in the PFS installation sleeve 52. If the same PFS installation sleeve 52 needs to be adapted to flanges 12 of two sizes, the PFS fixing claw 524 needs to be lengthened so that it can pass over the long side of the large flange 122 and reach the inner circle position of the flange 12. However, the longer PFS fixing claw 524 is actually In order to achieve free reset, the material requirements are high, and the PFS fixing claw 524 only realizes mechanical reset. After reset, the distance between the bottom of the PFS fixing claw 524 and the PFS fixing platform 523 is fixed. Generally, it is necessary to leave some gap between the bottom of the PFS fixing claw 524 and the upper surface of the flange 12 after natural reset. Otherwise, the buffer pad 8 needs to be compressed during installation to achieve installation. However, when the buffer pad 8 is reset, or when puncturing with a needle, the flange 12 squeezes the PFS fixing claw 524 upward. At this time, the bottom of the PFS fixing claw 524 is subjected to an upward force. In addition to elastic deformation upward, it will also deform inward, which may contact the push rod 7, thereby hindering the injection. However, if there is a gap, the flange 12 will not be able to fully fit with the buffer pad 8, making the buffering effect of the buffer pad 8 not obvious.

[0223] Based on this, the installation and fixing method of PFS1 in PFS installation sleeve 52 was redesigned, referring to Figure 34 The PFS1 is installed in the PFS mounting sleeve 52 with the buffer pad 8, the bottom surface of the buffer pad 8 rests on the PFS fixing platform 523, and the top surface of the buffer pad 8 supports the bottom surface of the flange 12 of the PFS1; a clamping member 9 is provided on the top of the flange 12 of the PFS1, and the clamping member 9 is an elastic member. The top surface of the clamping member 9 is limited by the lower part of the injection spring sleeve 62, so that the clamping member 9 is elastically pressed on the top of the flange 12, and the flange 12 is firmly fixed in the PFS mounting sleeve 52.

[0224] Cushion 8, such as Figure 37 As shown, the PFS1 syringe 11 has a through hole 81 for passing through. A buffer platform 82 is provided outside the through hole 81, and its size matches that of the small flange 121. A pad 83 is preferably provided outside the buffer platform 82, and its size matches that of the large flange 122. Preferably, both sides of the buffer pad 8 also have relief surfaces 84 that are substantially flush with the surfaces on both sides of the large flange 122. Fixing protrusions 85 are preferably provided at both ends of the buffer pad 8.

[0225] PFS installation sleeve 52, such as Figure 38 As shown, there is a PFS1 installation cavity on the inner side, and a PFS fixing platform 523 at the bottom. There are clearance holes 525 on both sides of the installation cavity for the needle removal / hidden needle stimulation device of the automatic injection pen to pass through for stimulation. Correspondingly, the clearance holes 525 are adapted to the surfaces on both sides of the large flange 122; further, limiting protrusions 5252 are provided on both sides of the clearance hole 525.

[0226] The cushion 8 can be installed into the PFS installation sleeve 52 first, as shown in FIG. Figure 39 As shown; the clearance surface 84 of the buffer pad 8 is aligned with the clearance hole 525 of the PFS mounting sleeve 52, and does not block the clearance hole 525; accordingly, the limiting protrusion 5252 abuts against the clearance surface 84 of the buffer pad 8 to prevent the buffer pad 8 from deflecting in the PFS mounting sleeve 52 and blocking the clearance hole 525. Figure 40 、 Figure 41 As shown, a positioning mounting hole 529 is provided on the wall of the PFS mounting sleeve 52, and the fixing protrusions 85 on both sides of the buffer pad 8 are just inserted into the positioning mounting hole 529, so that the buffer pad 8 can be stably positioned and reliably installed in the PFS mounting sleeve 52, that is, the buffer pad 8 is prevented from deflecting in the PFS mounting sleeve 52, and the buffer pad 8 is prevented from falling off from the PFS mounting sleeve 52.

[0227] The pressing member 9 is made of plastic, such as Figure 42 、 Figure 43 As shown, it has a pressing surface 91, which is preferably in the shape of a circular ring, matching the size of the small flange 121 and the size of the inscribed circle of the large flange 122; an elastic body 92 is provided above the pressing surface 91, and the elastic body 92 is preferably a hollow structure, which realizes elastic deformation through a thin solid structure; preferably, the elastic body 92 is designed with two petals, and there is a makeshift space between the two petals, which is adapted to the orientation and size of the makeshift hole 525.

[0228] The pressing surface 91 of the pressing member 9 is relatively small, while the upper fixed end is relatively large, so the lower side of the elastic body 92 is relatively small and the upper side is relatively large for connection.

[0229] A top pressure surface 94 is provided on the top of the elastic body 92 ; further, the top of the elastic body 92 extends upward to form a limiting fixing portion, including an outer limiting body 95 and an inner limiting body 96 .

[0230] like Figure 44As shown, the compression member 9 is preferably coupled to the bottom of the injection spring sleeve 62; the bottom surface of the injection spring sleeve 62 is provided with a pressure surface 629 that abuts against the top pressure surface 94. The pressure surface 629 applies downward pressure to the top pressure surface 94, causing the elastic body 92 to deform appropriately. The bottom outer surface of the injection spring sleeve 62 is preferably provided with a slot for the outer limiter 95 to snap into, while the inner limiter 96 is clamped on the inner side of the bottom of the injection spring sleeve 62. The outer limiter 95 and the inner limiter 96 simultaneously clamp the injection spring sleeve 62 from both inside and outside, ensuring the orientation stability between the compression member 9 and the injection spring sleeve 62 and ensuring that the top pressure surface 94 always abuts against the pressure surface 629, preventing the top pressure surface 94 from shrinking inward due to the elastic deformation of the elastic body 92 and losing contact with the pressure surface 629.

[0231] like Figure 45 、 Figure 46 As shown, the buffer pad 8 can adapt to the small flange 121 and the large flange 122 at the same time; the small flange 121 can fall on the buffer platform 82 of the buffer pad 8 and obtain elastic support; the large flange 122 can fall on the pad 83 of the buffer pad 8 and also obtain appropriate support; if the buffer platform 82 and the pad 83 are completely connected together, the elastic deformation of the rubber will be small, resulting in insufficient buffering effect; therefore, the buffer platform 82 and the pad 83 are separated and there is a groove in the middle, so as to reduce the size of the elastomer to obtain a better buffering effect.

[0232] like Figure 47 As shown, the cushion 8 is installed in place within the PFS mounting sleeve 52, and the PFS1 is installed. When the large flange 122 is used, the flat surfaces on both sides of the large flange 122 are also pressed against by the limiting protrusions 5252, limiting the position and preventing the protruding portions of the large flange 122 from blocking the clearance hole 525. When the small flange 121 is used, the small flange 121 is inherently small and insufficient to block the clearance hole 525. The pressing member 9 is then pressed in, and the pressing surface 91 of the pressing member 9 is securely pressed against the inner area of ​​the flange 12. The center of the pressing surface 91 is a hole that aligns with the inner hole of the syringe 11 of the PFS1, allowing the push rod to penetrate and engage with the piston.

[0233] Specific usage, such as Figure 48 、 Figure 49As shown; the buffer pad 8 is installed in the PFS mounting sleeve 52, and the clamping piece 9 is installed below the injection spring sleeve 62; the PFS1 is installed in the buffer pad 8 and the PFS mounting sleeve 52, and then the other components of the automatic injection pen are installed, and then the clamping piece 9 and the injection spring sleeve 62 are installed. When the injection spring sleeve 62 is buckled with the PFS mounting sleeve 52, the pressure surface 629 of the injection spring sleeve 62 applies a certain pressure to the top pressure surface 94 of the clamping piece 9, so that the elastomer 92 undergoes appropriate elastic deformation, and then presses the flange 12 downward through the clamping surface 91, so that the flange 12 is always fixed between the clamping piece 9 and the buffer pad 8; the buffer pad 8 and the clamping piece 9 simultaneously provide elastic buffering and limiting for the flange 12 of the PFS1 in the upper and lower directions, ensuring the safe use of the PFS1 in the automatic injection pen.

[0234] 4. Needle length / puncture depth adaptation adjustment

[0235] In actual use, 1. The different indications of different drugs result in different injection depths; 2. The viscosity of different drugs is different, and some viscosities even reach 40cp and above. For this reason, drug manufacturers may choose special prefilled needles, such as BD Neopak XtraFlow glass prefilled syringes (the inner diameter of the needle is larger than that of ordinary prefilled needles, and the needle length is shorter than that of ordinary prefilled needles); when the injection depth and needle length change, the present invention adapts by adjusting the length of the excitation sleeve 31.

[0236] 1. The needle length is the same, but the puncture injection depth in step 2 is different; Figure 50 、 Figure 52 As shown, by replacing different excitation sleeves 31 for assembly and use, the distance of the needle 13 exposed from the excitation surface 311 can be adjusted, thereby meeting the different requirements of the pharmaceutical manufacturer for the puncture depth of the needle 13 for different pharmaceuticals 10 used, at least including a shallower 4.0mm depth, a conventional 6.0mm depth, and a deeper 8.0mm depth.

[0237] The trigger sleeves 31 and 31' have the same main structure, and only the length of the exposed end 318 is different. The length difference of the exposed end 318 between the conventional trigger sleeve 31 and the short trigger sleeve 31' is Δ=2.0mm. When the two trigger sleeves of different lengths are assembled with other components to form an automatic injection device and an automatic injection pen, Figure 51 Before use, the length of the exposed end 318 beyond the outer sleeve 21 is also different, and the difference is Δ; in the second step of use, when puncturing, the puncture depth of Δ depth difference is generated (such as Figure 50 、 Figure 52As shown), the conventional puncture penetration depth is L=6.0 mm. After using the short excitation sleeve 31', the puncture penetration depth is deepened to L'=8.0 mm.

[0238] Finally, after completing the needle closing in step 4, Figure 53 、 Figure 54 、 Figure 55 As shown, the needle hidden depth M of the needle 13 hidden in the excitation surface 311 of the excitation sleeve 31 is also different, with the same difference Δ. After using the short excitation sleeve 31', the needle hidden depth M' of the needle 13 hidden in the excitation surface 311 is relatively shorter.

[0239] See further Figure 56 (a), (b) or (c), (d) in (a); Figure 56 It is shown that when the needle lengths are different, matching can also be achieved by adjusting the length of the excitation sleeve 31, especially adjusting the length of the exposed end 318 of the lower portion of the excitation sleeve 31, as shown in the following table.

[0240] shape (a) (b) (c) (d) Needle length Z / mm Za=8.0 Zb=8.0 Zc=12.7 Zd=12.7 Exposed end 318 length W / mm Wa=16.3 Wb=15.8 Wc=21.0 Wd=19.5 Needle insertion depth L / mm La=6.5 Lb=7.0 Lc=6.5 Ld=8.0

[0241] 5. Adjustment of the structure of the pen cap 23

[0242] As mentioned above, the length of the needle 13 may be adjusted, and the corresponding protective caps, especially the structure and size of the outer hard protective cap 16 will be adjusted, and the pen cap 23 needs to be adapted to it; and as mentioned above, after using the short excitation sleeve 31', the needle 13 is hidden in the excitation surface 311. The needle hidden depth M' is relatively shorter, which will also make the needle tip more easily exposed. In order to meet relevant safety requirements, it is necessary to reduce the diameter of the puncture hole 312 of the excitation sleeve 31 (regular version, short version, etc.) at this time to improve the safety of the needle 13 after it is hidden, and the corresponding pen cap 23 also needs to be appropriately structurally improved.

[0243] like Figure 57 、 Figure 58 As shown, a special protective cap tube 232 is stamped out of thin-walled metal and then assembled with the pen cap cover 231, or the protective cap tube 232 is placed in an injection mold and connected to the pen cap cover 231 by injection molding to form a pen cap 23 with a thin-walled protective cap tube; the inner wall of the protective cap tube 232 protrudes inward to form a plurality of protective cap claws 2326 for clamping the protective cap, so that the protective cap can be pulled off the needle 13 together when removing the pen cap 23 in step 1; the lower part or bottom of the protective cap tube 232 extends outward to form a connector 2323, in order to provide a larger connector for reliable and effective connection with the pen cap cover 231.

[0244] After using the metal pull-out cap tube 232, the space occupied between the inner wall of the puncture hole 312 and the outer wall of the cap can be reduced. At the same time, the cap claws 2326 have better elasticity, can fully extend inward, and engage with the hard cap 16, meeting the requirements of step one.

[0245] 5. Adjustment of the connection structure of the pen cap 23

[0246] In order to improve the storage and transportation safety and reliability of the automatic injection pen, it is necessary to reinforce the connection between the pen cap 23 and the pen body to prevent the unlocking triggering mechanism from being accidentally triggered.

[0247] Specific structure such as Figures 59-63 As shown, the upper portion is a pen cap cover 231 , which is used to connect with the bottom of the outer sleeve 21 .

[0248] A cap-pull-out tube 232 is provided in the middle of the pen cap along the axial direction of the injection pen, which is used to connect with the cap outside the needle 13, especially the hard cap 16. The cap-pull-out tube 232 can be integrally injection-molded with other parts of the pen cap (such as Figure 59 、 Figure 60 As shown), it can also be manufactured separately, such as stamping a metal tube and then combining it with other parts of the pen cap (such as Figure 61 、 Figure 62 As shown), in order to enable the hard protective cap 16 to be removed smoothly by pulling out the protective cap tube 232 when the pen cap 23 is removed, a cap pulling mechanism is provided on the protective cap tube 232, which can be as shown in FIG. Figure 59 As shown, the hook 2322 is located at the top of the protective cap tube 232. The hook 2322 extends inwardly and can hook the top of the hard protective cap 16. Figure 61 、 Figure 62 As shown, the cap claw 2326 is located at the upper part of the cap removal tube 232 . The cap claw 2326 is an elastic cantilever that extends inward and can buckle the thick part of the hard cap 16 .

[0249] One of the improvements of the pen cap of the present invention is that a locking mechanism and an unlocking mechanism are provided on the inner wall of the pen cap sleeve 231 .

[0250] The locking mechanism is that a plurality of locking blocks 233 are provided on the top of the inner wall of the pen cap cover 231 .

[0251] The unlocking mechanism is that a plurality of unlocking blocks 234 are provided on the inner wall of the pen cap cover 231 .

[0252] To ensure reliable connection, the locking mechanism and the unlocking mechanism are generally evenly arranged at two or more locations along the inner wall of the pen cap sleeve 231.

[0253] The second improvement of the pen cap of the present invention is that a cap body is also provided at the lower part of the pen cap sleeve 231, surrounding the exposed part of the excitation sleeve 31 that extends beyond the bottom of the outer sleeve 21. The cap body is provided with limiting claws 235, which are generally evenly arranged at 2 or more locations. The limiting claws 235 are set downward to limit the axial position of the excitation sleeve 31.

[0254] like Figure 64 As shown, the connection parts between the outer sleeve 21 and the excitation sleeve 31 and the pen cap 23 are provided with a mechanism matching the relevant structure for fixing and unlocking the pen cap 23.

[0255] A cap barrel is provided at the bottom of the outer sleeve 21 for connecting with the cap sleeve 231 of the pen cap 23; a limit platform 2142 is provided on the upper part of the cap barrel of the outer sleeve 21, and an introduction inclined surface 2143 is connected to the lower part of the limit platform 2142 which is inclined downward in the axial direction; one side of the limit platform 2142 ( Figure 64 The left side of the center) is provided with a guide bar 2141 arranged in the axial direction, and the guide bar 2141 extends to the lower part of the cap barrel; the other side of the limit platform 2142 ( Figure 64 The middle right side is the yield space.

[0256] In the middle and lower part of the cap barrel of the outer sleeve 21, a recessed unlocking guide groove is provided. The unlocking guide groove has an unlocking inclined surface 2144 inclined downward along the arc surface. One side of the unlocking guide groove ( Figure 64 A guide limit surface 2145 is provided (on the middle left side).

[0257] A limiting protrusion 318 is provided at the lower portion of the exposed end of the excitation sleeve 31 .

[0258] like Figure 65 、 Figure 66 As shown, the pen cap connection structure is formed by connecting the pen cap 23 with the outer sleeve 21 and the excitation sleeve 31; during assembly, the pen cap sleeve 231 of the pen cap 23 is axially inserted into the cap barrel of the outer sleeve 21, and one side of the locking block 233 abuts against the side of the guide bar 2141, and then moves upward along the guide bar 2141, and then reaches the guide slope 2143, and then the locking block 233 moves upward along the guide slope 2143 (at this time, the open end of the pen cap sleeve 231 of the pen cap 23 is elastically deformed outward), and finally passes over the limit platform 2 142, rests on the top of the limit platform 2142 to achieve locking; while the locking block 233 is inserted upward to lock, the unlocking block 234 is also inserted into the unlocking guide groove, and one side of the unlocking block 234 rests on the guide limit surface 2145 and is inserted upward and finally positioned, so that one direction of the circumferential rotation of the pen cap 23 is limited, and it only has the rotational freedom in the other direction, that is, the unlocking block 234 can rotate along the downward inclined direction of the unlocking guide groove, and at the same time the locking block 233 rotates toward the side of the clearance space of the limit platform 2142.

[0259] Furthermore, when the pen cap 23 is in a locked state, there are two unlocking blocks 234 located in the same unlocking guide groove, which are arranged at intervals, thereby improving the connection and locking reliability of the pen cap 23 on the cap barrel of the outer sleeve 21; among them, the long unlocking block 2342 is abutting against the guide limit surface 2145, and the short unlocking block 2341 is spaced apart from it; the short unlocking block 2341 and the long unlocking block 2342 are both narrow blocks, thereby reducing the friction between the unlocking block 234 and the unlocking guide groove during the unlocking movement.

[0260] When unlocking, hold the outer sleeve 21 with one hand and the pen cap 23 with the other hand, and apply a rotational force in a specified direction between the pen cap 23 and the outer sleeve 21, so that the top of the unlocking block 234 slides along the unlocking inclined surface 2144 of the unlocking guide groove; while rotating, the pen cap 23 moves downward, and the locking block 233 is screwed into the clearance space on the side of the limit platform 2142, and the pen cap 23 is free, so that the pen cap 23 can be removed.

[0261] When locked, the limiting claw 235 of the pen cap 23 is located directly above the limiting protrusion 318 at the exposed end of the activation sleeve 31; furthermore, when the pen cap 23 moves directly downward in the axial direction, the limiting claw 235 will abut against the limiting protrusion 318 to restrict the downward movement of the pen cap 23; similarly, when the activation sleeve 31 tends to move upward during storage and transportation of the automatic injection pen, the limiting protrusion 318 will also be abutted by the limiting claw 235 and cannot move upward.

[0262] Furthermore, preferably, a limiting groove 317 is provided above the limiting protrusion 318 at the exposed end of the excitation sleeve 31, so that the limiting protrusion 318 is flush with the other main body parts of the exposed end of the excitation sleeve 31, and thus the limiting claw 235 is located in the limiting groove 317; furthermore, a removal slope 319 is provided on at least one side of the limiting groove 317, so that when the pen cap 23 is rotated to unlock, the limiting claw 235 can slide along the removal slope 319, move to the outside of the limiting groove 317, away from the limiting protrusion 318, and thus gain freedom.

[0263] Furthermore, an indicator mark 237 is provided on the outside of the pen cap 23, that is, an arrow indicating the unlocking rotation direction of the pen cap 23, so that the operator can know the direction of rotation to unlock.

[0264] Furthermore, a skirt 238 is provided at the bottom of the pen cap 23 to increase the bottom area of ​​the pen cap 23 , thereby enabling the automatic injection pen to obtain reliable support when it is desired to be placed vertically.

[0265] Furthermore, the skirt 238 is provided with a plurality of grooves 2382, which facilitate gripping by the operator's fingers. This allows the operator to grasp the skirt 238 for rotational unlocking, thereby achieving a larger rotational lever arm and reducing the rotational unlocking force. Furthermore, the provision of the grooves 2382 also eliminates the bottom of the pen cap 23 from being a perfect circle, thereby preventing the autoinjector pen from rolling and accidentally falling when placed horizontally on a table.

[0266] 6. The connection structure between the top cover 22 and the outer sleeve 21 is improved.

[0267] First, the locking structure between the outer sleeve 21 and the top cover 22 is improved.

[0268] like Figure 68 As shown, the upper portion of the inner side of the outer sleeve 21 (near the top) is provided with a limiting edge 2191 arranged in an arc shape along the inner wall of the cylinder cavity 212; the limiting edges 2191 are symmetrically arranged.

[0269] At the height of the arc of the limiting edge 2191 , the wall surface of the cylindrical cavity 212 bulges inward to form a limiting platform 2192 .

[0270] A fixing portion 213 is provided above the lower part of the arc of the limiting edge 2191 , where a slot is provided.

[0271] The fixing portion 213 is further recessed outward along the wall of the cylindrical cavity 212 to form a positioning groove 2153 ; a trumpet-shaped introduction port 2154 is provided at the top of the positioning groove 2153 . The positioning groove 2153 is preferably a part of the guide groove 2152 .

[0272] like Figure 69 、 Figure 70 、 Figure 71 As shown, the top cover 22 has a cover body 221 and a cover top 222 ; the cover body 221 can be inserted into the top of the barrel cavity 212 of the outer sleeve 21 to seal the top of the outer sleeve 21 .

[0273] The bottom of the cover body 221 of the top cover 22 is symmetrically arc-shaped, forming a limiting bottom 223 that matches the shape of the limiting edge 2191 .

[0274] Since the cover body 221 is arc-shaped, two larger fixed parts are formed. The fixed parts can elastically deform inward, and the smaller areas are the weak links in the structure to accommodate the elastic deformation. On the fixed parts, they bulge outward to form a locking hook 224. The bottom of the locking hook 224 is an inclined loading slope 2242. Further, the outside of the locking hook 224 further bulges outward to form a positioning protrusion 225. The size of the positioning protrusion 225 matches the width of the positioning groove 2153.

[0275] like Figure 72 、 Figure 73、 Figure 74 As shown, the top cover 22 is installed on the top of the outer sleeve 21. When it is closed, the locking hooks 224 are aligned with the position of the fixing parts 213, and the inclined surfaces 2242 are in contact with the top opening of the cylinder cavity 212. The pressure of installing the top cover 22 downward is applied, so that the fixing parts on both sides of the locking hooks 224 on both sides of the top cover 22 are elastically deformed inward, so that the cover body 221 of the top cover 22 can be inserted into the cylinder cavity 212; then, the positioning protrusions 225 are snapped into the positioning grooves 2153 through the introduction port 2154, ensuring that the locking hooks 224 are aligned with the fixing parts 213; finally, the top cover 22 is installed in place on the top of the outer sleeve 21. At this time, the arc of the limiting bottom 223 of the top cover 22 is aligned with the limiting edge 219 of the outer sleeve 21 1 matches and contacts the arc shape of 1, the smaller area of ​​the top cover 221 rests on the limit platform 2192, the combination of the limit bottom 223 and the limit edge 2191, as well as the combination of the smaller area of ​​the top cover 221 and the limit platform 2192 limit the downward movement trend of the top cover 221; at the same time, the locking hook 224 is smoothly inserted into the fixing portion 213, and the locking hook 224 hooks the top edge of the fixing portion 213 to limit the upward movement trend of the top cover 221; the up and down movement trends of the top cover 221 are all limited, and due to the combination of the limit bottom 223 and the limit edge 2191, the axial movement trend of the top cover 221 is also limited. At this point, the top cover 221 is fully and reliably fixed to the top of the outer sleeve 21.

[0276] The present invention further improves the locking structure between the top cover 22 and the unlocking sleeve 32 .

[0277] The top cover 22 utilizes the position of the locking hook 224 to make the wall surface bulge inward to form a locking platform 227, and an inclined locking guide surface 2272 is provided below the locking platform 227.

[0278] Further preferably, there is a clearance space 226 above the locking platform 227 ; the clearance space 226 can penetrate the wall surface of the cover body 221 of the top cover 22 , so that the cover body 221 is connected inside and outside at the clearance space 226 .

[0279] Further preferably, a limiting protrusion 228 is provided above the locking platform 227 in the clearance space 226 , and the limiting protrusion 228 protrudes inwardly, and the amount of the inward protrusion of the locking platform 227 is almost equal.

[0280] like Figure 75 As shown, the unlocking sleeve 32 has a fixed spring claw 326 on the top wall; Figure 76 、 Figure 77 As shown, the main body of the fixed spring claw 326 is a locking hook 3263; the top of the locking hook 3263 is connected to the top of the unlocking sleeve 32, and the other three sides are hollowed out to form a hollow cavity 3264, so that the locking hook 3263 is an elastic hook that can be elastically deformed at the bottom.

[0281] The bottom surface of the locking hook 3263 is a locking surface 3265 protruding outward.

[0282] Preferably, an inclined elastic guide surface 3266 is provided above the locking surface 3265.

[0283] like Figure 78 、 Figure 79 、 Figure 80 As shown, when the unlocking sleeve 32 is unlocked, it moves upward along the axis of the outer sleeve 21, so that the top of the unlocking sleeve 32 enters the top cover 22 and is locked with the top cover 22; during the process, the middle and lower parts of the locking hook 3263 contact the locking platform 227, especially the locking guide surface 2272 contacts the elastic guide surface 3266, and the two inclined surfaces contact, converting the axial force into a horizontal force, so that the locking hook 3263 elastically deforms inwardly until the locking hook 3263 completely passes over the locking platform 227 and arrives above the locking platform 227, and the locking surface 3265 overlaps axially with the locking platform 227. When the cam 226 is in the unlocking state, the locking surface 3265 of the locking hook 3263 is inserted into the clearance space 226 on the wall of the cover body 221, thereby achieving a better locking effect. At the same time, the locking hook 3263 is inserted into the clearance space 226 on the wall of the cover body 221 to limit the axial rotation of the unlocking sleeve 32. At the same time, the top of the unlocking sleeve 32 is pressed against the limiting protrusion 228, thereby preventing the unlocking sleeve 32 from shaking and causing the locking to fail.

[0284] 7. Activate the guide structure of the unlocking sleeve.

[0285] During the insertion and firing process in step 2, the triggering and unlocking sleeve must move relative to the outer sleeve 21 (actually, the triggering surface 311 of the triggering sleeve 31 abuts against the outer sleeve 21, and then the outer sleeve 21 drives the internal components connected to it downward). Because the triggering and unlocking sleeve and the outer sleeve 21 are both slender tubes, relative movement between them is the primary requirement for the use of the autoinjector pen of the present invention, and therefore reliable relative movement between the two is required.

[0286] like Figure 81 As shown, the unlocking sleeve is provided with multiple axial motion guide structures from bottom to top, including a guide portion 313 at the bottom and a guide protrusion 316 in the middle.

[0287] like Figure 82 As shown, the guide portion 313 is stuck between the guide bodies 215, and the contact length between the two is long, thereby achieving stable positioning and guiding.

[0288] like Figure 83 、 Figure 84 As shown, the guide protrusion 316 is stuck in the guide groove 2152 to achieve reliable axial guidance.

[0289] Furthermore, a guide structure is also provided on the unlocking sleeve 32 , including an elastic arm 327 provided at the lower portion of the unlocking sleeve 32 and a guide groove 328 provided at the upper portion of the unlocking sleeve 32 .

[0290] The elastic arm 327 protrudes from the wall of the unlocking sleeve 32 and includes a spring 3271, one end of which (the top is shown in the figure) is connected to the wall of the unlocking sleeve 32, and the other end extends outward to form a convex point 3272, which is adapted to the guide groove 2152. Figure 84 As shown, the protrusion 3272 is located just above the guide protrusion 316 and is also stuck in the guide groove 2152 to achieve reliable axial guidance.

[0291] The guide groove 328 is provided at the top of the unlocking sleeve 32 along the axis. The phase of the guide groove 328 is staggered with the phase of the fixed spring claw 326, and is distributed at intervals of 90 degrees as shown in the figure. Accordingly, the top cover 22 needs to be further improved, such as Figure 85 As shown, a guide slider 229 is provided at a position 90° out of phase with the locking platform 227; Figure 86 As shown, the guide slider 229 is just stuck in the guide groove 328. The figure shows the state before excitation. Only the bottom of the guide slider 229 is stuck in the guide groove 328. As the excitation starts, the guide slider 229 is continuously stuck in the guide groove 328. The two cooperate to achieve reliable axial guidance.

[0292] As mentioned above, the excitation unlocking sleeve is provided with four axial guides from bottom to top, which can effectively provide limiting and positioning, and realize good excitation guidance.

[0293] Further improvements of the present invention are as follows: Figure 84 As shown, the spring piece 3271 of the elastic arm 327 is fully opened outward. When the unlocking sleeve 32 is installed into the outer sleeve 21, the spring piece 3271 is compressed inward, so that not only an axial guide is formed between the protrusion 3272 and the guide groove 2152, but also positive pressure is formed. When the excitation is in progress, a certain friction resistance is generated between the protrusion 3272 and the guide groove 2152, so that in the use step two, the outer sleeve 21 drives the internal parts combined with it to move downward together, and a slight resistance is generated, thereby causing the operator to slow down the process, making the puncture process of the needle 13 more soothing, and improving the patient experience.

[0294] 8. Pre-assembly of the trigger unlocking sleeve.

[0295] like Figures 87-90As shown, after the trigger unlocking sleeve is assembled with other internal components, it needs to be pre-assembled with the top cover 22 and then installed into the outer sleeve 21; at this time, the top cover 22 is pre-assembled with the top of the unlocking sleeve 32 of the trigger unlocking sleeve. The guide slider 229 of the top cover 22 is inserted into the guide groove 328 of the unlocking sleeve 32, so that the two are directionally positioned; then, the top cover 22 is pressed downward in the direction of the unlocking sleeve 32, so that the locking guide surface 2272 of the top cover 22 contacts the elastic guide surface 3266 of the unlocking sleeve 32, and the two are squeezed, so that a certain binding force is generated between the top cover 22 and the unlocking sleeve 32, which is not easy to loosen, as shown in FIG. Figure 88 、 Figure 89 As shown, the locking surface 3265 does not go beyond the elastic guide surface 3266, completely locking the two axially.

[0296] Further, such as Figure 85 As shown, the center of the top cover 22 is downwardly positioned (in the figure, the top cover 22 is inverted and appears upward) with a plurality of elastic clips 2210, four of which are shown in groups of two and arranged opposite each other. The lower portions of the elastic clips 2210 are provided with outward-facing limiting protrusions 2211. During the above process, the elastic clips 2210 of the top cover 22 are inserted between the two fixed elastic arms 73 at the top of the push rod 7. In particular, the limiting protrusions 2211 extend beyond the locking grooves 74 and engage below them, thereby pre-assembling the top cover 22 and the push rod 7. The two elastic clips 2210 on each side are located on either side of the safety protrusion 324, and together stabilize one fixed elastic arm 73 and the locking groove 74 through the limiting protrusions 2211 below.

[0297] 9. Improvement of needle closing spring 51.

[0298] like Figures 91 to 93 As shown, circumferential limits are set at the upper and lower limits of the needle withdrawal spring 51; specifically, a spring upper circumferential limit 5222 is provided on the inner side of the needle withdrawal spring upper limit 522 of the PFS mounting sleeve 52, which, together with the inner wall of the guide cylinder 521, limits the inner and outer sides of the top of the needle withdrawal spring 51; a plurality of spring lower circumferential limits 415 are provided on the outer circle of the needle withdrawal spring lower limit 414 of the needle withdrawal spring base 4, which, together with the wall surface of the syringe 11, limit the inner and outer sides of the bottom of the needle withdrawal spring 51; this can effectively improve the stability of the needle withdrawal spring 51 when it is released.

[0299] At the same time, the upper and lower limits of the needle-retracting spring 51 place the position of the needle-retracting spring 51 in a compressed state at the height position when the piston 14 is not activated. Since the needle-retracting spring 51 is made of metal and is opaque, the position of the needle-retracting spring 51 overlaps with the piston 14, so that the medicine 10 in the syringe 11 below the piston 14 can be exposed as much as possible, making it convenient to directly observe the medicine 10 from the outside through the transparent shell and other components, and it is also more beautiful.

[0300] Furthermore, an appropriate amount of grease 53 is filled in the gap between the connecting tube 43 of the needle withdrawal spring base 4 and the guide tube 521 of the PFS mounting sleeve 52; in this way, when the needle withdrawal spring 51 in the fourth step of use is unlocked and activated, the PFS mounting sleeve 52 moves upward relative to the needle withdrawal spring base 4 under the action of the needle withdrawal spring 51. At this time, due to the presence of the grease 53, a viscous force is generated in the gap, thereby slowing down the needle withdrawal speed, slowing down the speed of pulling out the needle from the patient's body, and providing a better patient experience.

[0301] The preferred embodiments of the present invention have been specifically described above, but the present invention is not limited to the described embodiments. Those skilled in the art may make various equivalent modifications or substitutions without departing from the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. An automatic injection pen for prefilled syringes, characterized in that It includes a pre-filled syringe PFS, which is installed in an automatic injection device; The automatic injection device includes an outer pen housing, an activation and unlocking sleeve, a needle retraction spring base, and a syringe; The outer pen shell includes an outer sleeve and a detachable pen cap; An activation and unlocking sleeve is provided slidingly inside the outer sleeve; The fixed portion of the needle-retracting spring base passes through the trigger unlocking sleeve and is connected to the outer sleeve; the needle-retracting spring base is fixed in the outer sleeve; The upper part of the needle retraction spring base is equipped with a needle retraction spring and a releasable injection cylinder; The injection cylinder is composed of the PFS mounting sleeve and the injection spring sleeve connected together; An injection spring is installed inside the injection spring sleeve; a push rod is provided inside the injection spring, and a releasable structure at the top of the push rod is connected to the top of the injection spring sleeve; The bottom of the trigger unlocking sleeve is provided with a trigger portion which can be extended beyond the bottom of the outer sleeve; The top of the trigger unlocking sleeve is provided with an unlocking portion, which matches the release portion at the top of the push rod to unlock the injection spring; The push rod is provided with an unlocking part, which matches the release part of the needle closing spring to unlock the needle closing spring; The flange of the PFS is installed in the PFS mounting sleeve, and the main body of the PFS syringe passes through the PFS mounting sleeve and is inserted into the needle retraction spring base; Before injection, the PFS is connected to the outer sleeve through the needle retraction spring base; the needle of the PFS passes through the needle retraction spring base so that the puncture part of the needle passes over the bottom of the outer sleeve.

2. The automatic injection pen for prefilled syringes according to claim 1, wherein A mounting portion is provided on the inner side of the sleeve body of the outer sleeve; A mounting buckle is provided on the outer wall of the needle-retracting spring base; The mounting portion of the outer sleeve is combined with the mounting buckle of the needle shrinking spring base to achieve the installation and fixation of the needle shrinking spring base in the outer sleeve.

3. The automatic injection pen for prefilled syringes according to claim 2, wherein: The mounting portion of the outer sleeve includes a lower limit platform and an upper limit platform; The mounting buckle of the needle-retracting spring base includes a stop block and a hook; The abutment block abuts against the lower limit platform; The hook is engaged with the upper limit platform; Axial upper and lower limit fixation is achieved between the needle shrinking spring base and the outer sleeve.

4. The automatic injection pen for a prefilled syringe according to claim 3, wherein: There are two lower limit platforms and stop blocks, and an upper limit platform and hook in the middle; The lower limit platforms and the stop blocks on both sides radially limit the upper limit platform and the hook in the middle.

5. The automatic injection pen for prefilled syringes according to claim 3, wherein: Above the mounting portion of the outer sleeve, there is an axially extending guide bar, with two guide bars being provided, located on both sides of the mounting portion; A connecting buckle groove is provided on the connecting tube of the needle spring base, and the connecting buckle groove matches the guide strip to achieve radial limitation; The mounting buckle of the needle shrinking spring base is arranged in the connecting buckle groove.

6. The automatic injection pen for prefilled syringes according to claim 1 or 3, characterized in that: An elastic locking arm is provided on the upper part of the needle-retracting spring base, and the upper part of the elastic locking arm protrudes inward to form a needle-retracting lock buckle, and the upper part of the needle-retracting lock buckle is provided with a needle-retracting triggering inclined surface; The lower outer side of the PFS mounting sleeve is provided with a needle-reduction locking hook, which matches the needle-reduction lock buckle; When the needle closing lock buckle and the needle closing locking hook are connected together, the needle closing spring base is connected to the PFS mounting sleeve, and the needle closing spring is in a compressed state; The needle retraction lock buckle is disengaged from the needle retraction locking hook, and the needle retraction spring base and the PFS mounting sleeve can slide axially. The needle retraction spring is in an unlocked and excited state, which can push the syringe barrel to move axially away from the needle retraction spring base.

7. The automatic injection pen for a prefilled syringe according to claim 6, wherein: Both sides of the middle portion of the push rod extend downward to form a needle-retracting unlocking portion with a free end; The free end of the needle reduction unlocking portion matches the needle reduction excitation inclined surface of the needle reduction spring base.

8. The automatic injection pen for a prefilled syringe according to claim 1, wherein Before the injection spring is unlocked and activated, the pusher head of the push rod is inserted into the syringe or located outside the syringe, and the pusher head is spaced from the piston in the syringe; After the injection spring is unlocked and activated, the push head contacts the piston. Under the thrust of the injection spring, the push head drives the piston to move axially in the syringe to inject the medicine.

9. The automatic injection pen for a prefilled syringe according to claim 1, wherein Before the needle closing spring is unlocked and activated, the PFS together with the PFS mounting sleeve are connected to the outer sleeve through the needle closing spring base; After the needle retraction spring is unlocked and activated, the PFS installation sleeve drives the PFS to move axially upward in the outer pen shell under the thrust of the needle retraction spring, and the needle is completely retracted into the activation unlocking sleeve.

10. The automatic injection pen for a prefilled syringe according to claim 1, wherein The flange of PFS is installed in the PFS installation sleeve, which is combined with the needle spring base to limit the axial position; the needle spring base is fixedly installed in the outer sleeve to limit the axial position; The lower part of the needle-retracting spring base is extended outward to be provided with a plurality of positioning claws, and the lower inner side of the outer sleeve is provided with a guide body. The positioning claws of the needle-retracting spring base are in contact with the guide body of the outer sleeve to limit the axial position.

11. The automatic injection pen for a prefilled syringe according to claim 1, wherein A buffer pad is provided under the flange of the PFS, and an elastic pressing member is provided above the flange of the PFS; The bottom of the pressing piece is the pressing surface, which is annular and matches the inner circle size of the flange; An elastic body is provided above the pressing surface, the elastic body is in a compressed state, and a top pressing surface is provided on the top of the elastic body; The bottom surface of the injection spring sleeve is provided with a pressure surface, and the pressure surface of the injection spring sleeve is in contact with the top pressure surface of the pressing piece.

12. The automatic injection pen for a prefilled syringe according to claim 1, wherein The length of the exposed end of the activating sleeve can be adjusted according to the puncture depth and / or the length of the needle installed in the syringe.

13. The automatic injection pen for a prefilled syringe according to claim 1, wherein A cap-protecting tube made of thin-walled metal is provided inside the pen cap; The inner wall of the cap-protecting tube is bulged inwards to form a plurality of cap-protecting claws.

14. The automatic injection pen for a prefilled syringe according to claim 1, wherein The upper part of the pen cap is the pen cap cover, which is detachably connected to the bottom of the outer sleeve; a cap removal tube is provided in the middle of the pen cap along the axial direction of the injection pen, and the cap removal tube is connected to the protective cap outside the needle; A locking mechanism and an unlocking mechanism are provided on the inner wall of the pen cap; The locking mechanism is that a number of locking blocks are provided on the top of the inner wall of the pen cap; The unlocking mechanism is that a number of unlocking blocks are provided on the inner wall of the pen cap; A cap body is also provided at the lower part of the pen cap sleeve, and a limiting claw is provided in the cap body; A cap barrel is provided at the bottom of the outer sleeve, a limit platform is provided on the upper part of the cap barrel, and a guide inclined surface inclined axially downward is connected to the lower part of the limit platform; a guide strip arranged axially is provided on one side of the limit platform; and a clearance space is provided on the other side of the limit platform; A recessed unlocking guide groove is provided in the middle and lower part of the cap barrel of the outer sleeve. The unlocking guide groove has an unlocking inclined surface inclined downward along the arc surface, and a guide limit surface is provided on one side of the unlocking guide groove; A limiting protrusion is provided at the lower part of the exposed end of the excitation sleeve; The locking block of the pen cap is located above the limit platform of the cap barrel of the outer sleeve when locked; The unlocking block of the pen cap is located in the unlocking guide groove of the cap barrel of the outer sleeve when locked, and one or more unlocking blocks abut against the guide limit surface on one side of the unlocking guide groove, and the top of one or more unlocking blocks contacts the unlocking inclined surface of the unlocking guide groove; The limiting claw of the pen cap is located above the limiting protrusion at the exposed end of the excitation sleeve when locked.

15. The automatic injection pen for a prefilled syringe according to claim 1, wherein A top cover is provided on the top of the outer sleeve, and the top cover is fixedly connected to the top of the outer sleeve; The upper portion of the inner side of the outer sleeve is provided with a limiting edge arranged in an arc shape along the inner wall of the cylinder cavity; At the height of the arc of the limiting edge, the wall surface of the cylinder cavity bulges inward to form a limiting platform; A fixing portion with a slot is provided above the lower part of the arc of the limiting edge; The top cover comprises a cover body and a cover top; The bottom of the cover body of the top cover is symmetrically arc-shaped, forming a limiting bottom that matches the shape of the limiting edge; The cover is arc-shaped, thereby forming two fixing parts with larger areas, and the fixing parts can be elastically deformed inwards; on the fixing parts, outward protrusions are formed to form locking hooks; the locking hooks are engaged with the card slots.

16. The automatic injection pen for a prefilled syringe according to claim 15, wherein: The wall surface at the location of the locking hook of the top cover is convex inward to form a locking platform, and an inclined locking guide surface is provided below the locking platform; Above the locking table is the give-way space; A fixed spring claw is provided on the wall surface at the top of the unlocking sleeve; the main body of the fixed spring claw is a locking hook; the top of the locking hook is connected to the top of the unlocking sleeve, and the other three sides are hollowed out to form a hollow cavity; The bottom surface of the locking hook is a locking surface protruding outward; After the unlocking sleeve is fully unlocked, the locking surface of the locking hook passes over the locking guide surface and reaches above the locking platform.

17. The automatic injection pen for a prefilled syringe according to claim 1, wherein There are multiple axial motion guide structures between the trigger unlocking sleeve and the outer sleeve from top to bottom, including: A guide portion is provided at the bottom of the trigger unlocking sleeve, and a guide body is provided on the inner side of the bottom of the outer sleeve, and the guide portion is clamped between the guide bodies; A guide protrusion is provided in the middle of the trigger unlocking sleeve, and a guide groove is provided in the axial direction on the inner upper part of the outer sleeve, and the guide protrusion is stuck in the guide groove; An elastic arm is provided above the guide protrusion that activates the unlocking sleeve, and the spring piece of the elastic arm extends outward to form a protrusion, which is stuck in the guide groove.

18. The automatic injection pen for a prefilled syringe according to claim 17, wherein: The elastic arm that activates the unlocking sleeve is installed in the outer sleeve in a state of being compressed and deformed inwards, and there is positive pressure between the protrusion and the guide groove.

19. The automatic injection pen for a prefilled syringe according to claim 17, wherein: An axial motion guide structure is provided between the trigger unlocking sleeve and the top cover on the top of the outer sleeve; A long straight guide groove is provided on the top of the trigger unlocking sleeve along the axial direction, and a guide slide block is provided on the top cover, and the guide slide block is stuck in the guide groove.

20. The automatic injection pen for a prefilled syringe according to claim 19, wherein There are several elastic buckles downwardly provided in the middle of the top cover, and the lower part of the elastic buckles is provided with outward limiting protrusions; When the top cover is pre-assembled, the elastic buckle of the top cover is inserted between the two fixed elastic arms at the top of the push rod, and the limiting protrusion is stuck under the locking groove.

21. The automatic injection pen for a prefilled syringe according to claim 1, wherein The gap between the shrinking spring base and the PFS mounting sleeve is filled with buffer grease.

Images