Automatic injection pen

Abstract

The invention relates to an automatic injection pen which comprises a lower pen shell pre-assembly module and an upper pen shell pre-assembly module, and a pre-filling syringe is installed in the automatic injection pen. The lower pen shell pre-assembling module comprises three parts, namely a lower pen shell, a pen cap and an excitation sleeve; the upper pen shell pre-assembly module comprises an upper pen shell, a push rod, an injection spring, a safety pin, a retraction sleeve, an injection spring support, a needle retracting spring base, a needle retracting spring and eight parts. The pen cap is connected with the bottom of the lower pen shell, the lower pen shell is connected with the upper pen shell, and a mounting cavity for other parts is formed in the lower pen shell. The automatic injection pen can effectively guarantee the safety of the storage and transportation process of products, and is convenient to use and operate.

Description

Technical Field

[0001] The invention relates to an automatic injection pen and belongs to the field of medical injectors. Background Art

[0002] An automatic injection pen is a syringe product that is convenient for patients or ordinary people to operate. During production, the manufacturer first fills the liquid medicine into the syringe to form a prefilled syringe (Prefilled Syringe, PFS, also known as a drug-loaded syringe). Figure 4 As shown; then load the PFS into the automatic injection device to form an automatic injection pen for transportation and sale. After obtaining the automatic injection pen, consumers use it as needed, remove the pen cap, and then press it on the patient's injection site to stimulate the injection, and finally remove the injection pen to complete the automatic injection of the liquid medicine; compared with traditional syringes, it eliminates the process of using a disposable syringe to draw medicine, pierce the needle, and push the medicine, making the operation more convenient, and the injection dose can be guaranteed, and there will be no deviation in the injection dose due to unskilled operation.

[0003] There are many PFS auto-injection pens with one-time fully automatic injection function on the market, which are convenient for patients to use. However, due to regulatory requirements, the needle needs to be shielded before and after use to avoid needle injuries. Therefore, two sets of spring systems are generally required inside to implement the functions of pushing the drug injection and removing the needle for shielding. Therefore, the structure of the auto-injection pen is generally more complicated, which makes the automatic injection device more complicated when assembled with PFS.

[0004] However, after completing the production of the drug and filling it to form PFS, when assembling the entire pen, the pharmaceutical manufacturer often hopes to simplify the assembly process as much as possible, that is, most of the structural parts of the automatic injection device are completed at the manufacturer's end of the automatic injection device. This can reduce the facilities and equipment for loading PFS and improve assembly efficiency.

[0005] Therefore, considering the final assembly requirements of pharmaceutical manufacturers and the terminal's requirements for safe and convenient use of automatic injection pens, it is necessary to improve the structure of automatic injection pens, especially to optimize the structure of the automatic injection device. Summary of the invention

[0006] The purpose of the present invention is to provide an automatic injection pen, so that the automatic injection pen can be easily assembled during the production process, especially to achieve modular assembly when delivered to a drug manufacturer; after the injection pen is formed, the storage and transportation can be stable and reliable; and when the patient finally obtains it for use, it is easy to operate.

[0007] To achieve the above-mentioned object of the invention, the present invention provides an automatic injection pen, comprising a lower pen housing pre-assembly module and an upper pen housing pre-assembly module, wherein a pre-filled syringe is installed inside;

[0008] A lower pen shell pre-assembly module, including a lower pen shell, a pen cap, and an excitation sleeve;

[0009] The upper pen shell pre-assembly module includes eight parts: the upper pen shell, the push rod, the injection spring, the safety pin, the retraction sleeve, the injection spring bracket, the needle closing spring base, and the needle closing spring;

[0010] The pen cap is connected to the bottom of the lower pen shell, the lower pen shell is connected to the upper pen shell, and the interior is a mounting chamber for other parts;

[0011] The trigger sleeve is movably mounted in the lower pen housing, and the upper part of the trigger sleeve forms a trigger piece which can unlock and push the safety pin;

[0012] The needle closing spring base is fixedly installed at the lower part of the upper pen shell, and the needle closing spring is sleeved on the needle closing spring base;

[0013] The retraction sleeve is unlockably mounted on the needle retraction spring base; an injection spring bracket is arranged in the retraction sleeve and an injection spring is installed therein; the injection spring is installed in the push rod;

[0014] The bottom of the push rod is connected to the piston of the prefilled syringe; the top of the push rod is unlockably mounted on the top of the retraction sleeve;

[0015] The safety pin is movably installed in the upper pen shell, and an excitation pin is arranged in the safety pin. The excitation pin is removably installed on the inner side of the top of the push rod.

[0016] As a further improvement of the present invention, the lower pen housing comprises an outer shell, wherein a housing cavity is provided in the outer shell;

[0017] A PFS mounting sleeve is provided in the housing cavity, and a chamber for storing a syringe of a prefilled syringe is formed in the PFS mounting sleeve;

[0018] A channel is formed between the shell cavity and the PFS installation sleeve, which is connected vertically and through which the excitation sheet of the excitation sleeve can be inserted and moved.

[0019] Furthermore, an observation window is provided on the lower pen housing;

[0020] The PFS installation sleeve is a transparent sleeve, or the PFS installation sleeve is provided with an observation window that matches the observation window of the lower pen housing.

[0021] As a further improvement of the present invention, the excitation sleeve has an excitation tube at the bottom, and the excitation tube is slidably mounted on the bottom inner side of the outer shell of the lower pen shell;

[0022] The excitation tube of the excitation sleeve is upwardly formed with two excitation sheets, and the excitation sheets are slidably arranged in the channel of the lower pen shell.

[0023] As a further improvement of the present invention, the push rod includes a push rod barrel, the inner side of the push rod barrel is a spring chamber for storing the injection spring; more than two fixed arms are provided on the top of the push rod barrel, and a clearance chamber is provided between adjacent fixed arms; the top of the fixed arm protrudes outward to form a fixed claw, and a contraction guide is formed below the end of the fixed claw.

[0024] Furthermore, a piston cone head is provided downwardly at the bottom of the push rod tube of the push rod.

[0025] Furthermore, a syringe stopper protruding outward is provided at the lower part of the push rod cylinder of the push rod, and the syringe stopper has elasticity that can shrink inward;

[0026] The distance between the syringe stopper and the piston cone matches the distance between the piston and the top opening of the prefilled syringe when the filled medicament is not in use.

[0027] As a further improvement of the present invention, the safety pin has two movable arms, the bottoms of the two movable arms are downwardly extended with elastic excitation claws, the bottoms of the excitation claws are outwardly protruding to form an excitation hook, and the excitation hook is detachably buckled into the bottom of the upper pen shell; the lower part of the excitation hook is provided with an excitation guide;

[0028] The tops of the two movable arms of the safety pin are connected through a connecting top, and the connecting top is provided with an excitation pin column protruding downward, and the excitation pin column matches the safety pin accommodating cavity formed by the top of the fixed arm of the push rod.

[0029] Furthermore, a guide arm is provided between the two movable arms of the safety pin, and the guide arm is connected below the connecting top; a longitudinal guide groove is formed between the movable arm and the guide arm;

[0030] A plurality of longitudinally raised guide strips are arranged inside the shell of the upper pen shell; the guide strips match the guide grooves.

[0031] As a further improvement of the present invention, the retracting sleeve comprises a sleeve body, the bottom of the sleeve body of the retracting sleeve is connected to a connecting tube with a smaller outer diameter; the lower part of the connecting tube of the retracting sleeve is an elastic needle-retracting fixing claw, the bottom outer protrusion of the needle-retracting fixing claw forms a needle-retracting fixing hook, and the upper part of the needle-retracting fixing hook has a needle-retracting guide; the interior of the needle-retracting fixing claw forms a push rod guide cavity, which matches the push rod tube;

[0032] The bottom of the retracting sleeve forms a step plane, the upper part is a needle-retracting support surface, and the lower part is a top abutting plane of the needle-retracting spring.

[0033] As a further improvement of the present invention, a narrow spring seat is provided on the top of the injection spring support; both sides of the narrow spring seat extend downward to form a connecting arm, and the bottom of the connecting arm is connected to the retracting sleeve.

[0034] Furthermore, the middle of the narrow spring seat of the injection spring bracket extends downward to form a slender spring positioning column, and the spring positioning column is inserted into the inner side of the injection spring.

[0035] As a further improvement of the present invention, the needle-retracting spring base has a spring cylinder, and the needle-retracting spring is sleeved on the spring cylinder; the bottom of the spring cylinder extends outward to form an annular spring seat; the spring seat of the needle-retracting spring base is fixedly installed in the upper pen housing;

[0036] The bottom of the needle-retracting spring abuts against the spring seat of the needle-retracting spring base; the top of the needle-retracting spring abuts against the bottom plane of the sleeve body of the retracting sleeve.

[0037] The automatic injection pen of the present invention is first produced and preassembled by the injection device manufacturer to form a lower pen shell preassembled module and an upper pen shell preassembled module, and the two preassembled modules are delivered to the drug manufacturer.

[0038] The pre-assembly of the lower pen shell pre-assembly module includes three parts: the lower pen shell, the pen cap, and the excitation sleeve; the excitation sleeve is installed into the lower pen shell from the bottom, and then the pen cap is inserted to form the lower pen shell pre-assembly module; at this time, the top of the lower pen shell pre-assembly module is an open mouth.

[0039] The pre-assembly of the upper pen shell pre-assembly module includes eight parts: the upper pen shell, the push rod, the injection spring, the safety pin, the retraction sleeve, the injection spring bracket, the needle closing spring base, and the needle closing spring; the needle closing spring is sleeved on the needle closing spring base, and then the bottom of the sleeve body of the retraction sleeve is against the top of the needle closing spring and moves toward the needle closing spring base, so that the needle closing fixing hook passes over the spring tube and presses against the bottom of the spring tube, and the needle closing fixing claw is located in the spring tube, and the needle closing spring is compressed; then the push rod is installed so that the middle and lower part of the push rod tube of the push rod is located in the push rod guide cavity on the inner side of the needle closing fixing claw, so that the needle closing fixing claw cannot shrink and deform inward; at this time, the fixing claw at the top of the push rod hooks the top plane of the sleeve body of the retraction sleeve; the injection spring is installed in the spring cavity of the push rod, and then the injection spring bracket is installed on the top of the injection spring, the spring positioning column is inserted into the injection spring, the narrow spring seat presses against the top of the injection spring and compresses the injection spring downward, and finally the narrow spring seat is snapped into the let-down of the push rod The locking cam is then engaged with the spring support and the spring is engaged with the spring support, and the locking cam ...

[0040] The automatic injection pen of the present invention is assembled with a lower pen shell preassembly module and an upper pen shell preassembly module and a prefilled syringe at a pharmaceutical manufacturer, and the prefilled syringe is loaded into the lower pen shell preassembly module, and the prefilled syringe is loaded from the open port at the top of the lower pen shell preassembly module, and the syringe is inserted into the inner shell, and the protective cap is inserted into the protective cap holder, so that the assembly of the prefilled syringe and the lower pen shell preassembly module is completed; then the upper pen shell preassembly module is installed, and the connector of the upper pen shell is inserted into the top of the lower pen shell, and the guide inclined surface is squeezed to make the connector shrink and deform inward, until the pen shell fixing block completely falls into the shell fixing groove, and the pen shell positioning strip is inserted into the pen shell positioning groove, and the piston cone head is inserted into the piston; and with the insertion of the connector, the excitation head is attached to the inner wall of the upper pen shell and reaches the upper pen shell preassembly module, and the excitation head is aligned with the excitation guide of the excitation hook; the automatic injection pen of the present invention can be quickly formed.

[0041] The automatic injection pen of the present invention, when delivered to a patient, comprises the following steps when used:

[0042] Step 1. The patient removes the pen cap; the patient holds the pen body (lower pen shell, upper pen shell) with one hand and the pen cap with the other hand, applies force to separate the pen cap from the lower pen shell. At this time, the pen cap will remove the protective cap together, leaving the needle in the excitation sleeve exposed, but the needle is still in the excitation sleeve and is shielded by the excitation sleeve.

[0043] Step 2, the patient performs the injection; the patient holds the pen body, places the bottom plane of the guard ring of the ignition sleeve against the site to be injected, and then applies pressure toward the body to retract the ignition sleeve into the lower pen shell; at this time, the needle gradually passes over the guard ring and penetrates into the injection site, completing the injection action;

[0044] As the ignition sleeve moves upward relative to the lower pen housing, the ignition head contacts the ignition guide of the ignition hook and converts the longitudinal force into an inward contraction deformation force of the ignition hook along the inclined surface of the ignition guide 3, so that the ignition hook is disengaged from the safety pin connection groove. Further, the ignition head pushes the safety pin to move upward as a whole, so that the ignition pin column is disengaged from the safety pin accommodating cavity at the top of the push rod fixed arm, so that the internal mechanism of the automatic injection pen of the present invention can realize injection and needle collection in a continuous manner under the thrust of the injection spring and the needle collection spring. The specific action process is as follows:

[0045] Action 2.1, the fixing claw retracts inwards; when the trigger pin is disengaged from the safety pin accommodating cavity at the top of the fixing arm, there is no limit inside the fixing claw, and then under the elastic expansion force of the injection spring, the push rod tends to move downward, and at this time, the contraction guide converts the downward force of the fixing arm into a force for the fixing arm to contract and deform inwards, so that the fixing claw slides along the top of the sleeve body through the contraction guide; finally, the fixing claw completely separates from the top plane of the sleeve body and enters the interior of the sleeve body, so that the push rod is in a state of being pushed downward by the thrust of the injection spring;

[0046] Action 2.2, during the injection process, the syringe stopper is compressed and squeezed into the syringe; after the push rod moves downward for a certain distance, the syringe stopper contacts the top of the syringe, and the syringe stopper is compressed and deformed inward until it is completely compressed and squeezed into the syringe; at this time, the push rod has driven the piston to move downward for a certain distance, thus achieving drug injection;

[0047] Action 2.3, during the injection process, the push rod pushes the piston to continue to move downward; the narrow spring seat is just located in the clearance cavity between the fixed arms and does not affect the downward movement of the push rod;

[0048] Action 2.4, injection is completed, the push rod pushes the piston to move to the bottom of the syringe, at this time the fixed claw of the push rod also moves to the bottom of the sleeve body, resting on the platform at the bottom of the sleeve body; and the clearance cavity between the fixed arms also moves to the bottom of the sleeve body, located on the inner side of the needle-retracting fixed claw;

[0049] Action 2.5, the needle-retracting fixed claw retracts inwardly; when the push rod barrel of the push rod moves downwardly away from the position of the needle-retracting fixed claw, the clearance cavity between the fixed arms moves to the position of the needle-retracting fixed claw. At this time, the interior of the needle-retracting fixed claw is no longer unlimited, and then under the action of the needle-retracting spring, the top of the needle-retracting spring pushes the step surface at the bottom of the sleeve body, so that the retraction sleeve has an upward movement trend, and then the needle-retracting fixed claw also moves upward, and the needle-retracting guide on the upper part of the needle-retracting fixed hook contacts the bottom of the spring seat, converting the upward force into a force for the needle-retracting fixed claw to retract and deform inwardly, so that the needle-retracting fixed claw slides along the bottom of the spring seat through the needle-retracting guide; finally, the needle-retracting fixed claw is completely separated from the bottom of the spring seat and enters the spring barrel, so that the retraction sleeve is in a state of being pushed upward by the thrust of the needle-retracting spring;

[0050] Action 2.6, needle retraction process; the needle retraction spring gradually expands, driving the retraction sleeve to move upward, and the bottom of the sleeve body of the retraction sleeve also drives the fixed claw of the push rod to move upward together; in this process, the piston cone head of the push rod drives the piston, and the piston drives the syringe through the friction between the piston and the bottom of the syringe, and the syringe drives the needle through the connecting force, and multiple parts move upward together; and as the needle moves upward, the needle is gradually pulled out from the injection site and hidden in the excitation sleeve.

[0051] Step 3: After the injection is completed and the needle is removed, the patient discards the automatic injection pen of the present invention after the injection.

[0052] The automatic injection pen of the present invention is produced and preassembled to form a lower pen shell preassembled module and an upper pen shell preassembled module, which are delivered to a drug manufacturer as two preassembled modules and then assembled with a prefilled syringe. The drug manufacturer uses the assembly process conveniently and quickly.

[0053] The automatic injection pen of the present invention has a simple and ingenious design of the triggering mechanism; the top of the push rod is locked and limited by the triggering pin of the safety pin; the push rod can be triggered by the injection spring to achieve drug injection only through the displacement of the safety pin; the bottom of the retracting sleeve is locked and limited by the push rod tube of the push rod; the retracting sleeve can be triggered by the needle retraction spring to achieve needle retraction and shielding only through the sufficient displacement of the push rod.

[0054] The automatic injection pen of the present invention can effectively ensure the safety of the storage and transportation process of the product and is easy to use and operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 This is the overall appearance diagram of the automatic injection pen of the present invention;

[0056] Figure 2 It is a schematic diagram of a pre-assembled module of the automatic injection pen of the present invention;

[0057] Figure 3 An exploded view of the components of the automatic injection pen of the present invention;

[0058] Figure 4 It is a schematic diagram of the overall structure of a prefilled syringe (PFS);

[0059] In the figure, 1-prefilled syringe (PFS); 11-sliding sleeve; 12-piston; 13-injection needle; 14-protective cap (cap, also called protective sheath); 15-flange (flange, also called flange);

[0060] Figure 5 The overall structural appearance diagram of the lower pen housing of the present invention is shown;

[0061] Figure 6 A cross-sectional view of the internal structure of the lower pen housing of the present invention;

[0062] Figure 7 The overall structural appearance diagram of the pen cap of the present invention;

[0063] Figure 8 is a cross-sectional view of the internal structure of the pen cap of the present invention;

[0064] Fig. 9 The figure is the overall structural appearance of the excitation sleeve of the present invention;

[0065] Fig.10 It is a partial cutaway schematic diagram of the excitation sleeve of the present invention;

[0066] Fig.11 It is a structural schematic diagram of the PFS installation sleeve of the present invention;

[0067] Fig.12 It is a schematic diagram of the structure of the PFS of the present invention installed in the lower pen housing component;

[0068] Fig.13 It is the overall cross-sectional view of the PFS after being installed in the lower pen shell pre-assembly module;

[0069] Fig.14 The overall structural appearance diagram of the upper pen housing of the present invention;

[0070] Fig.15 A cross-sectional view of the internal structure of the upper pen housing of the present invention;

[0071] Fig.16 The figure is a diagram of the overall structure of the push rod of the present invention;

[0072] Fig.17 is a cross-sectional view of the internal structure of the push rod of the present invention;

[0073] Fig.18 The overall structural appearance diagram of the safety pin of the present invention;

[0074] Fig.19 A cross-sectional view of the internal structure of the safety pin of the present invention;

[0075] Fig. 20 It is the overall structural appearance diagram of the retractable sleeve of the present invention;

[0076] Fig.21 It is a cross-sectional view of the internal structure of the retractable sleeve of the present invention;

[0077] Fig. 22 It is the overall structural diagram of the injection spring support of the present invention;

[0078] Fig.23 It is a schematic diagram of the structure of assembling the push rod, the injection spring and the injection spring bracket on the retraction sleeve;

[0079] Fig.24 This is a diagram of the overall structure of the needle-retracting spring base of the present invention;

[0080] Fig.25 A cross-sectional view of the internal structure of the needle-retracting spring base of the present invention;

[0081] Fig.26 This is the overall structural appearance diagram of the upper pen shell pre-assembly module of the present invention;

[0082] Fig. 27 It is a cross-sectional view of the internal structure of the upper pen shell pre-assembly module of the present invention;

[0083] Fig.28 The automatic injection device of the present invention is in a fully assembled and unused state;

[0084] Fig.29 The automatic injection method of the present invention is as follows: 1. The pen cap is removed;

[0085] Fig.30 Schematic diagram of the initial stage of step 2 of the automatic injection method of the present invention Figure 1 ;

[0086] Fig.31 Schematic diagram of the initial stage of step 2 of the automatic injection method of the present invention Figure 2 ;

[0087] Fig.32 A schematic diagram of step 2.1 of using the automatic injection of the present invention;

[0088] Fig.33 A schematic diagram of step 2.2 of using the automatic injection of the present invention;

[0089] Fig.34 This is a schematic diagram of the initial stage of step 2.3 of using the automatic injection of the present invention;

[0090] Fig.35 A schematic diagram of step 2.3 of using the automatic injection of the present invention;

[0091] Fig.36 This is a schematic diagram of the termination of step 2.3 of the automatic injection of the present invention;

[0092] Fig.37 A schematic diagram of steps 2.4 to 2.5 of using the automatic injection of the present invention;

[0093] Fig.38 A schematic diagram of step 2.6 of using the automatic injection of the present invention;

[0094] Fig.39 A schematic diagram of step 3 of using the automatic injection of the present invention;

[0095] Fig.40 Schematic diagram of the inward contraction deformation process of the fixed claw in step 2.1 of the automatic injection method of the present invention Figure 1 ;

[0096] Fig.41 Schematic diagram of the inward contraction deformation process of the fixed claw in step 2.1 of the automatic injection method of the present invention Figure 2 ;

[0097] Fig.42 It is a schematic diagram of the fixed claw sliding inside the sleeve body in step 2.3 of the use of the automatic injection of the present invention;

[0098] Fig.43 This is a schematic diagram of the automatic injection of the present invention using steps 2.2 and 2.3 in which the injection spring pushes the push rod to perform injection;

[0099] Fig.44 A schematic diagram of the movement of the push rod relative to the injection spring support in step 2.3 of the automatic injection of the present invention;

[0100] Fig.45 It is a schematic diagram of the process in which the yielding cavity continuously approaches the needle-retracting fixed claw at the end of step 2.3 of the automatic injection of the present invention;

[0101] Fig.46It is a schematic diagram of the change process of the needle-retracting fixing claw in step 2.5 of the automatic injection of the present invention;

[0102] Fig.47 Schematic diagram of step 2.6 for use of the automatic injection of the present invention. DETAILED DESCRIPTION

[0103] The specific implementation modes of the present invention are further described in detail below in conjunction with the accompanying drawings.

[0104] The object of the present invention is to provide an automatic injection pen, the overall structure of which when not in use is as follows: Figure 1 As shown, from bottom to top, it includes a pen cap 22, a lower pen shell 21, and an upper pen shell 31. An observation window is provided on the lower pen shell 21. The internal syringe 11 can be seen through a transparent PFS mounting sleeve or a PFS mounting sleeve also provided with an observation window, and the internal medicine state can be observed through the wall of the transparent syringe 11.

[0105] The automatic injection pen of the present invention is produced and preassembled by the injection device manufacturer to form a lower pen shell preassembled module 2 and an upper pen shell preassembled module 3, and the two preassembled modules are delivered to the drug manufacturer, and then assembled with the prefilled syringe 1, such as Figure 2 As shown, the prefilled syringe 1 is loaded into the lower pen shell preassembly module 2, and then the upper pen shell preassembly module 3 is installed, and the automatic injection pen of the present invention can be quickly formed. All the parts of the automatic injection pen of the present invention are as shown in FIG. Figure 3 shown.

[0106] Pen Shell Pre-assembled Module 2 ,like Figure 3 As shown, it includes four parts: a lower pen shell 21, a pen cap 22, an excitation sleeve 23, and a PFS installation sleeve 24.

[0107] Pen Shell 21 ,like Figure 5 , Figure 6 As shown, it includes an outer shell 211, within which is a shell cavity 212; an observation window 213 is provided on the outer shell 211; the inner wall of the outer shell 211, and located in the shell cavity 212, are provided with two protrusions, namely an excitation guide protrusion 215, and a PFS support protrusion 216; the two protrusions are arranged at intervals.

[0108] The top of the outer shell 211 is provided with a structure for connecting and fixing with the upper pen shell 31 of the upper pen shell pre-assembly module 3 . In this embodiment, a shell fixing groove 218 is provided on the top wall surface of the outer shell 211 .

[0109] Pen cap 22 ,like Figure 7 , Figure 8As shown, a cap shell 221 is provided on the outside, and the upper part of the cap shell 221 is a connecting shell 222, which is used to connect with the pen cap mounting surface 217 at the bottom of the lower pen shell 21; preferably, the inner wall of the cap shell 221 is provided with a pen cap positioning protrusion 2222, which matches the size and position of the pen cap positioning groove 2172 to achieve positioning between the lower pen shell 21 and the pen cap 22.

[0110] A protective cap holder 223 is provided inside the pen cap 22 for storing the protective cap 14 of the prefilled syringe 1 . The upper part of the protective cap holder 223 is composed of more than two cap claws 224 (in the present embodiment, two cap claws 224 are symmetrically arranged), the cap claws 224 are elastic, and the tops of the cap claws 224 form cap hooks 225 inwardly; the upper part of the cap hook 225 is a guiding inclined surface inclined inwardly, and when the prefilled syringe 1 is loaded into the lower pen shell preassembly module 2, the bottom of the protective cap 14 contacts the guiding inclined surface, so that the cap hook 225 can be pushed outward, and at this time, the cap claws 224 elastically deform outwardly; the bottom of the cap hook 225 is a plane, and when the prefilled syringe 1 is installed in place in the lower pen shell preassembly module 2, the protective cap 14 is just completely located in the protective cap holder 223, and at this time, the cap claws 224 are elastically reset, so that the cap hook 225 just clamps the top of the protective cap 14, and then the protective cap 14 is completely located in the protective cap holder 223, and when the pen cap 22 is pulled out at this time, the protective cap 14 will be pulled off from the syringe 11, thereby exposing the needle 13. Furthermore, a blocking bar 226 is provided at the bottom of the protective cap holder 223 to retain the protective cap 14 in the protective cap holder 223 to prevent it from falling off.

[0111] A plurality of fixed spring claws 227 are provided at the lower part of the wall surface of the protective cap holder 223 of the pen cap 22, and the lower part of the fixed spring claws 227 protrudes outward to form a pen cap fixing protrusion 228. The upper part of the pen cap 22 is limited by the lower pen shell 21 and cannot move upward, and the lower part of the pen cap 22 is connected to the excitation sleeve 23 through the pen cap fixing protrusion 228; when the pen cap 22 needs to be pulled off, it is necessary to apply force to pull it downward, at which time the pen cap fixing protrusion 228 moves inward against the bottom of the excitation sleeve 23, so that the fixed spring claws 227 shrink inward, until the pen cap fixing protrusion 228 leaves the excitation sleeve 23, and then the pen cap 22 can be pulled off.

[0112] Excitation sleeve 23 ,like Fig. 9 , Fig.10 As shown, an excitation tube 231 is provided at the bottom, and the excitation tube 231 can be slidably installed on the bottom inner side of the outer shell 211 of the lower pen shell 21; the bottom plane of the excitation tube 231 shrinks inward to form a protective ring 232, and the size of the protective ring 232 matches the pen cap fixing protrusion 228 and can be stuck on the pen cap fixing protrusion 228; at the same time, the size of the protective ring 232 is also small, which can prevent fingers from reaching in and avoiding touching the needle 13.

[0113] The excitation tube 231 of the excitation sleeve 23 forms two excitation pieces 233 upwards, and the excitation pieces 233 are slidably arranged in the channel 214 of the lower pen housing 21; an excitation head 234 is arranged on the top of the excitation piece 233, and an inclined excitation slope 235 is arranged on the top of the excitation head 234. Preferably, a longitudinal guide groove 236 is arranged on the excitation piece 233, and the guide groove 236 matches the excitation guide protrusion 215, and the two are combined to form a slide guide.

[0114] PFS Mounting Sleeve 24 ,like Fig.11 As shown, a mounting cylinder 241 is provided, inside of which is a PFS accommodating cavity 242; a supporting cylinder 243 is provided on the outer side of the mounting cylinder 241, and the supporting cylinder 243 matches the shell cavity 212 of the lower pen shell 21, and the two are connected and fixed, at which time the bottom surface 244 of the supporting cylinder 243 is connected to the PFS supporting protrusion 216; the mounting cylinder 241 is connected to the top surface of the supporting cylinder 243 to form a PFS flange platform for supporting the flange 15 of the PFS.

[0115] like Fig.12 As shown, the lower pen housing 21, the excitation sleeve 23, and the PFS installation sleeve 24 are preassembled together to form a structure for accommodating the PFS. At this time, in order to observe the prefilled syringe 1 through the observation window 213, the PFS installation sleeve 24 can be made transparent as a whole, or the PFS installation sleeve 24 can be locked in position between the lower pen housing 21, and then a corresponding observation window can be opened on the wall surface of the PFS installation sleeve 24 inside the observation window 213.

[0116] Further Fig.13 As shown, the prefilled syringe 1 is loaded from the open mouth at the top of the lower pen shell preassembly module 2, the syringe 11 is inserted into the PFS mounting sleeve 24, and the protective cap 14 is inserted into the protective cap holder 223, the flange 15 contacts the top surface of the mounting cylinder 241 to achieve positioning, and the PFS accommodating cavity 242 positions the prefilled syringe 1 as a whole; at this point, the assembly of the prefilled syringe 1 and the lower pen shell preassembly module 2 is completed.

[0117] Upper pen shell pre-assembled module 3 ,like Figure 3 As shown, it includes an upper pen housing 31, a push rod 41, an injection spring 42, a safety pin 43, a retraction sleeve 51, an injection spring bracket 52, a needle retraction spring base 61, and a needle retraction spring 62, a total of eight parts.

[0118] Upper pen case 31 ,like Fig.14 , Fig.15 As shown, it includes an upper shell 311, which is a cylindrical shell with an open lower end and a closed top 312; a connector 313 is provided at the lower part of the upper shell 311 for connecting with the top of the lower pen shell 21.

[0119] In order to achieve the connection between the upper pen shell 31 and the lower pen shell 21, the outer dimension of the wall of the connecting body 313 is smaller than the outer dimension of the wall of the upper shell 311, and the corresponding top wall of the lower pen shell 21 is thinned internally so as to match the connecting body 313; further, the connecting body 313 is provided with a longitudinal makeshift groove 3132, so that the connecting body 313 has elastic deformation space, which is convenient for inserting into the top of the lower pen shell 21; further, the connecting body 313 is provided with a raised pen shell fixing block 314, the number, position and size of which match the shell fixing groove 218, and further, the lower part of the pen shell fixing block 314 is provided with an insertion guide inclined surface 3142.

[0120] When the upper pen shell preassembly module 3 is loaded into the lower pen shell preassembly module 2, the connector 313 of the upper pen shell 31 is inserted into the top of the lower pen shell 21; during the insertion process, the guide slope 3142 first contacts the top wall of the lower pen shell 21, so that the wall of the connector 313 is elastically deformed by force until the pen shell fixing block 314 completely falls into the shell fixing groove 218, at which time the wall of the connector 313 is elastically restored; further, the cross-sections of the upper pen shell 31 and the lower pen shell 21 are not fully circular, and after being plugged in, they also have positioning and limiting functions to prevent the upper pen shell 31 and the lower pen shell 21 from rotating.

[0121] The upper pen shell 31 is also provided with a safety pin connection groove 316 and a needle spring base fixing groove 318, two installation grooves; in this embodiment, the safety pin connection groove 316 is located at the upper part, and the needle spring base fixing groove 318 is located at the lower part and located on the connecting body 313. A plurality of longitudinally protruding guide strips 317 are provided inside the shell of the upper pen shell 31.

[0122] Putter 41 ,like Fig.16 , Fig.17 As shown, it is an elongated cylinder, including a push rod cylinder 411, the upper end of the push rod cylinder 411 is open, the lower end is closed, the inner side of the push rod cylinder 411 is a spring chamber 412 for storing the injection spring 42; the top of the push rod cylinder 411 is provided with more than two fixed arms 413, and the space between adjacent fixed arms 413 is a clearance chamber 414; the top of the fixed arm 413 protrudes outward to form a fixed claw 415, and a contraction guide 416 is formed below the end of the fixed claw 415. In a natural state, the inner side walls of the tops of the plurality of fixed arms 413 are surrounded to form a safety pin accommodating chamber.

[0123] The outer diameter of the lower portion of the push rod barrel 411 of the push rod 41 is smaller than the inner diameter of the syringe 11 , so that the push rod 41 can be inserted into the syringe 11 without any obstacles and move along the axial direction of the syringe 11 .

[0124] A piston cone head 417 is provided downwardly at the bottom of the push rod barrel 411 of the push rod 41. In the present invention, the piston cone head 417 of the push rod 41 not only needs to apply a downward thrust to the piston 12 for injection, but also needs to apply an upward pulling force for needle retraction. Therefore, the piston cone head 417 not only has a downward conical surface, but also has a connecting rod with a cross-section smaller than the cross-section of the top of the piston cone head 417 between the push rod barrel 411, so that after the piston cone head 417 is inserted into the piston hole 121 of the piston 12, it is elastically wrapped by the piston 12, so that it can withstand the upward pulling force.

[0125] The lower part of the push rod barrel 411 of the push rod 41 is provided with a syringe stopper 418 protruding outward. The syringe stopper 418 has the elasticity to shrink inward and can shrink inward when subjected to force; the distance between the syringe stopper 418 and the piston cone head 417 matches the distance between the piston 12 and the top opening of the syringe 11 when the prefilled syringe 1 is not in use.

[0126] When the upper pen shell preassembly module 3 is loaded into the lower pen shell preassembly module 2, the piston cone head 417 is inserted into the top opening of the syringe 11, and finally completely inserted into the piston 12 and fixed with the piston 12; at this time, the bottom of the push rod barrel 411 of the push rod 41 is also inserted into the top opening of the syringe 11, and the syringe stopper 418 just abuts against the outside of the top opening of the syringe 11, thereby preventing the syringe 11 from being bumped during transportation, causing the impact force to move upward, causing the needle 13 to be accidentally pulled out of the protective cap 14, and causing the medicine to be ejected in advance, reducing the dosage.

[0127] Injection spring 42 , is a slender spring, the lower part of which is installed in the push rod barrel 411 of the push rod 41, and the bottom is against the bottom of the push rod barrel 411, exerting a downward thrust on the push rod 41; the upper part is in contact with the injection spring bracket 52. The elastic expansion stroke of the injection spring 42 is long enough to fully push the push rod 41 into the syringe 11, so that the piston cone head 417 drives the piston 12 to move along the axial direction of the syringe 11, and the piston 12 moves to the bottom of the syringe 11, and the medicine in the syringe 11 is completely injected.

[0128] Safety pin 43 ,like Fig.18 , Fig.19 As shown, there are two movable arms 431, and a connecting top is provided on the top of the movable arm 431. Furthermore, a guide arm 432 is provided between the two movable arms 431, and the guide arm 432 is also connected below the connecting top; a longitudinal guide groove 433 is formed between the movable arm 431 and the guide arm 432.

[0129] The bottom of the two movable arms 431 extends downward to form a mounting arm 434, which can be mounted in the upper pen shell 31 against the inner wall of the upper shell 311; further, an elastic excitation claw 435 is provided on the side of the mounting arm 434, and the bottom of the excitation claw 435 protrudes outward to form an excitation hook 436, which can be buckled into the safety pin connecting groove 316; the top of the excitation hook 436 has a flat fixing surface 4362, which is used to hook the top surface of the safety pin connecting groove 316 to achieve the fixation of the safety pin 43 in the upper pen shell 31; the lower part of the excitation hook 436 is provided with an inwardly inclined excitation guide 4363; before the automatic injection pen of the present invention is used, the excitation guide 4363 extends inward beyond the safety pin connecting groove 316, protrudes inward from the upper shell 311 of the upper pen shell 31, and matches the excitation head 234 and the excitation slope 235 of the excitation sleeve 23 of the lower pen shell pre-assembly module 2.

[0130] The connecting top of the safety pin 43 is provided with an excitation pin 437 protruding downward, and its size matches the safety pin accommodating cavity formed at the top of the fixed arm 413 of the push rod 41.

[0131] Retraction sleeve 51 ,like Fig. 20 , Fig.21 As shown, it is a cylinder with two ends opened, having a sleeve body 511 , and a spring bracket fixing groove 512 is provided at the lower part of the sleeve body 511 for connecting and fixing the injection spring bracket 52 .

[0132] The bottom of the sleeve body 511 of the retracting sleeve 51 is connected to a connecting tube with a smaller outer diameter, so that the bottom of the sleeve body 511 forms a step surface for abutting against the top of the needle retracting spring 62 .

[0133] The lower part of the connecting tube of the retracting sleeve 51 is an elastic needle-retracting fixing claw 513 , the bottom of the needle-retracting fixing claw 513 protrudes outward to form a needle-retracting fixing hook 514 , and the upper part of the needle-retracting fixing hook 514 has an inclined needle-retracting guide 515 .

[0134] A push rod guide cavity is formed inside the needle-retracting fixed claw 513, which matches the push rod tube 411; when the cylindrical tube of the push rod tube 411 is located in the push rod guide cavity, the needle-retracting fixed claw 513 cannot shrink and deform inward; when the cylindrical tube of the push rod tube 411 is not in the push rod guide cavity, the inner side of the needle-retracting fixed claw 513 is free and can achieve inward shrinkage and deformation.

[0135] Injection spring bracket 52 ,like Fig. 22As shown, there is a slender spring positioning column 521, and a narrow spring seat 522 is provided on the top of the spring positioning column 521 for limiting the top of the injection spring 42; both sides of the narrow spring seat 522 extend downward to form a connecting arm 523, and a bracket hook 524 is provided at the bottom of the connecting arm 523 for matching and connecting with the spring bracket fixing groove 512 of the retraction sleeve 51.

[0136] like Fig.23 As shown in the figure, the push rod 41, the retracting sleeve 51, and the injection spring bracket 52 are assembled together to compress and fix the injection spring 42, that is, the state of the automatic injection pen of the present invention before injection; the injection spring 42 is located in the push rod barrel 411 of the push rod 41, and the spring positioning column 521 of the injection spring bracket 52 is inserted into the injection spring 42; the bottom of the injection spring 42 is against the bottom of the inner cavity of the push rod barrel 411 of the push rod 41, applying a downward thrust to the push rod 41, and at this time, the outer side of the fixing claw 415 of the push rod 41 is placed on the top plane of the sleeve body 511 of the retracting sleeve 51 to achieve position limiting; injection The top of the injection spring 42 rests on the narrow spring seat 522 of the injection spring bracket 52, applying an upward thrust to the injection spring bracket 52, and at this time, the bracket hook 524 of the injection spring bracket 52 is stuck in the spring bracket fixing groove 512 of the sleeve body 511 of the retraction sleeve 51 to achieve fixation; during the use of the present invention, the bracket hook 524 is always located in the spring bracket fixing groove 512, so that the injection spring bracket 52 is always fixedly installed in the retraction sleeve 51; through the retraction sleeve 51, the position of the push rod 41 and the injection spring bracket 52 is locked, so that the injection spring 42 is compressed and fixed.

[0137] Needle spring base 61 ,like Fig.24 , Fig.25 As shown, it is a tube with openings at both ends, comprising a spring tube 611, on which the needle retraction spring 62 is sleeved; the bottom of the spring tube 611 extends outward to form an annular spring seat 612 for supporting the bottom of the needle retraction spring 62; the interior of the spring tube 611 is a connecting cavity 613 for the insertion of the lower connecting tube of the retraction sleeve 51.

[0138] The spring seat 612 of the needle-retracting spring base 61 further extends outward to form a base fixing claw 614, which is used to be inserted into the needle-retracting spring base fixing groove 318 of the upper pen shell 31. During use of the present invention, the base fixing claw 614 is always located in the needle-retracting spring base fixing groove 318, so that the needle-retracting spring base 61 is always fixed in the upper pen shell 31.

[0139] Needle closing spring 62, which is a spring with a relatively thick outer diameter and a relatively short length; the bottom of the needle closing spring 62 abuts against the spring seat 612 of the needle closing spring base 61. Since the needle closing spring base 61 is always fixed in the upper pen shell 31, the bottom of the needle closing spring 62 is fixed in position relative to the upper pen shell 31; the top of the needle closing spring 62 abuts against the bottom plane of the sleeve body 511 of the retraction sleeve 51, exerting an upward thrust on the retraction sleeve 51.

[0140] After the upper pen housing pre-assembly module 3 is assembled, Fig.26 , Fig. 27 As shown; the needle closing spring 62 is sleeved on the needle closing spring base 61, and then the bottom of the sleeve body 511 of the retracting sleeve 51 abuts against the top of the needle closing spring 62, and moves toward the needle closing spring base 61, so that the needle closing fixing hook 514 passes over the spring tube 611 and abuts against the bottom of the spring tube 611, and the needle closing fixing claw 513 is located in the spring tube 611, and the needle closing spring 62 is compressed; then the push rod 41 is installed, so that the middle and lower part of the push rod tube 411 of the push rod 41 is located in the push rod guide cavity on the inner side of the needle closing fixing claw 513, so that the needle closing fixing claw 513 cannot shrink and deform inward. The retraction sleeve 51 and the needle spring base 61 are separated by the thrust of the needle spring 62; at this time, the fixing claw 415 at the top of the push rod 41 hooks the top plane of the sleeve body 511 of the retraction sleeve 51; the injection spring 42 is installed in the spring cavity 412 of the push rod 41, and then the injection spring bracket 52 is installed on the top of the injection spring 42, the spring positioning column 521 is inserted into the injection spring 42, the narrow spring seat 522 presses against the top of the injection spring 42 to compress the injection spring 42 downward, and finally the narrow spring seat 522 is snapped into the yield cavity 414 of the push rod 41, and the connection The connecting arm 523 and the bracket hook 524 are installed in the sleeve body 511, and the connecting arm 523 shrinks and deforms inwards until the bracket hook 524 is inserted into the spring bracket fixing groove 512, so that the injection spring 42 is compressed and fixed; then the safety pin 43 is installed, so that the excitation pin 437 is inserted into the safety pin accommodating cavity formed by the top of the fixed arm 413 of the push rod 41, so that the fixed arm 413 cannot shrink and deform inwards, so that the fixed claw 415 reliably hooks the top plane of the sleeve body 511; finally, the whole is installed in the upper pen shell 31, and the guide bar 317 is inserted into the safety pin accommodating cavity. In the guide groove 433 of the full pin 43, the trigger claw 435 of the safety pin 43 shrinks and deforms inwards until the trigger hook 436 is buckled into the safety pin connecting groove 316, and the connecting body 313 is elastically deformed until the base fixing claw 614 of the needle spring base 61 is snapped into the needle spring base fixing groove 318 of the upper pen shell 31. At this time, the safety pin 43 and the needle spring base 61 are both fixed in the upper pen shell 31, and the positions of the various parts are relatively locked, especially the parts that compress and fix the injection spring 42 and the needle spring 62 are all mechanically limited by other parts to achieve safety locking. At this point, the upper pen shell pre-assembly module 3 of the present invention is formed.

[0141] The upper pen shell pre-assembly module 3 needs to be assembled with the pre-filled syringe 1 and the lower pen shell pre-assembly module 2. The connector 313 of the upper pen shell 31 is inserted into the top of the lower pen shell 21. The guide slope 3142 is squeezed to make the connector 313 shrink and deform inward until the pen shell fixing block 314 completely falls into the shell fixing groove 218, and the pen shell positioning strip 315 is inserted into the pen shell positioning groove 219. At the same time, the piston cone head 417 is inserted into the piston 12; and with the insertion of the connector 313, the excitation head 234 sticks to the inner wall of the upper pen shell 31 and reaches the upper pen shell pre-assembly module 3. The excitation head 234 is aligned with the excitation guide 4363 of the excitation hook 436. At this point, the automatic injection pen of the present invention is in an unused state, and can be stored and transported, such as Fig.28 shown.

[0142] The automatic injection pen of the present invention, when delivered to a patient, comprises the following steps when used:

[0143] Step 1: The patient removes the pen cap 22; Fig.29 As shown, hold the pen body (lower pen shell 21, upper pen shell 31) with one hand and hold the pen cap 22 with the other hand, apply force to separate the pen cap 22 from the lower pen shell 21, and the pen cap 22 will remove the protective cap 14 together, so that the needle 13 in the excitation sleeve 23 is in a naked state, but the needle 13 is still located in the excitation sleeve 23 and is shielded by the excitation sleeve 23.

[0144] Step 2, the patient performs the injection; the patient holds the pen body, places the bottom plane of the guard ring 232 of the ignition sleeve 23 against the site where the injection is required, and then applies pressure toward the body to retract the ignition sleeve 23 into the lower pen housing 21; at this time, the needle 13 gradually passes over the guard ring 232 and penetrates into the injection site, completing the injection action;

[0145] As the trigger sleeve 23 moves upward relative to the lower pen housing 21, the trigger head 234 contacts the trigger guide 4363 of the trigger hook 436, and along the inclined surface of the trigger guide 4363, the longitudinal force is converted into an inward contraction deformation force of the trigger hook 436, so that the trigger hook 436 is disengaged from the safety pin connection groove 316. Fig.30 Further, the trigger head 234 pushes the safety pin 43 to move upward as a whole, thereby causing the trigger pin 437 to disengage from the safety pin accommodating cavity at the top of the push rod 41 fixed arm 413, as shown. Fig.31 As shown, the internal mechanism of the automatic injection pen of the present invention can realize injection and needle collection continuously under the thrust of the injection spring 42 and the needle collection spring 62. The specific action process is as follows:

[0146] Action 2.1, the fixed claw 415 retracts inwards; Fig.32As shown in FIG. 4 , when the excitation pin 437 is disengaged from the safety pin accommodating cavity at the top of the fixed arm 413, the fixed claw 415 has no limit position inside, and then under the elastic expansion force of the injection spring 42, the push rod 41 tends to move downward. At this time, the contraction guide 416 converts the downward force of the fixed arm 413 into a force for the fixed arm 413 to contract and deform inward, so that the fixed claw 415 slides along the top of the sleeve body 511 through the contraction guide 416, as shown in FIG. Fig.40 , Fig.41 Finally, the fixed claw 415 is completely separated from the top plane of the sleeve body 511 and enters the interior of the sleeve body 511, so that the push rod 41 is in a state where the thrust of the injection spring 42 is applied downward, as shown Fig.34 As shown;

[0147] Action 2.2, during the injection process, the syringe stopper 418 is compressed and squeezed into the syringe 11; Fig.33 As shown, after the push rod 41 moves downward for a distance, the syringe stopper 418 contacts the top of the syringe 11, and the syringe stopper 418 is compressed and deformed inward until it is completely squeezed into the syringe 11, as shown in FIG. Fig.43 As shown; at this time, the push rod 41 has driven the piston 12 to move downward for a distance to achieve drug injection;

[0148] Action 2.3, during the injection process, the push rod 41 pushes the piston 12 to continue to move downward; Fig.34 , Fig.35 , Fig.36 ,and Fig.44 As shown, the narrow spring seat 522 is just located in the clearance cavity 414 between the fixed arms 413 and does not affect the downward movement of the push rod 41;

[0149] In the process, Fig.45 As shown, the clearance cavity 414 between the fixed arms 413 of the push rod 41 moves accordingly, and then continuously enters the lower area of ​​the sleeve body 511, gradually approaching the inner side of the needle-retracting fixed claw 513;

[0150] Action 2.4, the injection is completed, and the push rod 41 pushes the piston 12 to move to the bottom of the syringe 11, as shown in FIG. Fig.37 As shown, at this time, the fixed claw 415 of the push rod 41 also moves to the bottom of the sleeve body 511 and rests on the platform at the bottom of the sleeve body 511; and the clearance cavity 414 between the fixed arms 413 also moves to the bottom of the sleeve body 511 and is located on the inner side of the needle-retracting fixed claw 513;

[0151] Action 2.5, the needle-retracting fixed claw 513 is retracted inward; Fig.37 , Fig.46When the push rod barrel 411 of the push rod 41 moves downward away from the position of the needle closing fixed claw 513, the clearance cavity 414 between the fixing arms 413 moves to the position of the needle closing fixed claw 513. At this time, the interior of the needle closing fixed claw 513 is no longer unlimited, and under the action of the needle closing spring 62, the top of the needle closing spring 62 pushes the step surface at the bottom of the sleeve body 511, so that the retraction sleeve 51 has a tendency to move upward, thereby causing the needle closing fixed claw 513 to move upward accordingly, and the needle closing guide 515 on the upper part of the needle closing fixed hook 514 contacts the bottom of the spring seat 612, converting the upward force into a force for the needle closing fixed claw 513 to shrink and deform inwardly, so that the needle closing fixed claw 513 slides along the bottom of the spring seat 612 through the needle closing guide 515; finally, the needle closing fixed claw 513 is completely separated from the bottom of the spring seat 612 and enters the spring barrel 611, so that the retraction sleeve 51 is in a state of being pushed upward by the thrust of the needle closing spring 62, as shown in FIG. Fig.38 As shown;

[0152] Action 2.6, needle closing process; Fig.38 As shown, the needle retracting spring 62 is gradually expanded, driving the retracting sleeve 51 to move upward, and the bottom of the sleeve body 511 of the retracting sleeve 51 also drives the fixing claw 415 of the push rod 41 to move upward together, as shown in FIG. Fig.47 As shown; in this process, the piston cone 417 of the push rod 41 drives the piston 12, the piston 12 drives the syringe 11 through the friction between the piston 12 and the bottom of the syringe 11, and the syringe 11 drives the needle 13 through the connection force, and multiple parts move upward together; and as the needle 13 moves upward, the needle 13 is gradually pulled out from the injection site and hidden in the excitation sleeve 23, as shown in FIG. Fig.39 shown.

[0153] During this process, the push rod 41 also drives the injection spring bracket 52 and the retraction sleeve 51 to move upward through the injection spring 42 .

[0154] Step 3: After the injection is completed and the needle is removed, the patient discards the automatic injection pen of the present invention after the injection is completed. Fig.39 shown.

[0155] 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 violating 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, characterized in that: It includes a lower pen housing pre-assembly module and an upper pen housing pre-assembly module, and a pre-filled syringe is installed inside; A lower pen shell pre-assembly module, comprising a lower pen shell, a pen cap, and an excitation sleeve; A lower pen shell pre-assembly module, including a lower pen shell, a pen cap, and an excitation sleeve; The upper pen shell pre-assembly module includes eight parts: the upper pen shell, the push rod, the injection spring, the safety pin, the retraction sleeve, the injection spring bracket, the needle closing spring base, and the needle closing spring; The pen cap is connected to the bottom of the lower pen shell, the lower pen shell is connected to the upper pen shell, and the interior is a mounting chamber for other parts; The trigger sleeve is movably mounted in the lower pen housing, and the upper part of the trigger sleeve forms a trigger piece which can unlock and push the safety pin; The needle closing spring base is fixedly installed at the lower part of the upper pen shell, and the needle closing spring is sleeved on the needle closing spring base; The retraction sleeve is unlockably mounted on the needle retraction spring base; an injection spring bracket is arranged in the retraction sleeve and an injection spring is installed therein; the injection spring is installed in the push rod; The bottom of the push rod is connected to the piston of the prefilled syringe; the top of the push rod is unlockably mounted on the top of the retraction sleeve; The safety pin is movably installed in the upper pen shell, and an excitation pin is arranged in the safety pin. The excitation pin is removably installed on the inner side of the top of the push rod.

2. The automatic injection pen according to claim 1, characterized in that: The lower pen housing comprises an outer shell, wherein a housing cavity is arranged in the outer shell; A PFS mounting sleeve is provided in the housing cavity, and a chamber for storing a syringe of a prefilled syringe is formed in the PFS mounting sleeve; A channel is formed between the shell cavity and the PFS installation sleeve, which is connected vertically and through which the excitation sheet of the excitation sleeve can be inserted and moved.

3. The automatic injection pen according to claim 2, characterized in that: An observation window is provided on the lower pen housing; The PFS installation sleeve is a transparent sleeve, or the PFS installation sleeve is provided with an observation window that matches the observation window of the lower pen housing.

4. The automatic injection pen according to claim 1, characterized in that: The excitation sleeve has an excitation tube at the bottom, and the excitation tube is slidably mounted on the bottom inner side of the outer shell of the lower pen shell; The excitation tube of the excitation sleeve is upwardly formed with two excitation sheets, and the excitation sheets are slidably arranged in the channel of the lower pen shell.

5. The automatic injection pen according to claim 1, characterized in that: The push rod comprises a push rod barrel, the inner side of which is a spring cavity for storing an injection spring; more than two fixed arms are arranged on the top of the push rod barrel, and a clearance cavity is formed between adjacent fixed arms; the top of the fixed arm protrudes outward to form a fixed claw, and a contraction guide is formed below the end of the fixed claw.

6. The automatic injection pen according to claim 5, characterized in that: The bottom of the push rod tube of the push rod is downwardly provided with a piston cone head.

7. The automatic injection pen according to claim 5, characterized in that: The lower part of the push rod cylinder of the push rod is provided with a syringe stopper protruding outwards, and the syringe stopper has the elasticity of shrinking inwards; The distance between the syringe stopper and the piston cone matches the distance between the piston and the top opening of the prefilled syringe when the filled medicament is not in use.

8. The automatic injection pen according to claim 1, characterized in that: The safety pin has two movable arms, the bottoms of the two movable arms are downwardly extended with elastic excitation claws, the bottoms of the excitation claws are outwardly protruding to form excitation hooks, and the excitation hooks are detachably buckled into the bottom of the upper pen shell; the lower part of the excitation hook is provided with an excitation guide; The tops of the two movable arms of the safety pin are connected through a connecting top, and the connecting top is provided with an excitation pin column protruding downward, and the excitation pin column matches the safety pin accommodating cavity formed by the top of the fixed arm of the push rod.

9. The automatic injection pen according to claim 8, characterized in that: A guide arm is provided between the two movable arms of the safety pin, and the guide arm is connected below the connecting top; a longitudinal guide groove is formed between the movable arm and the guide arm; A plurality of longitudinally raised guide strips are arranged inside the shell of the upper pen shell; the guide strips match the guide grooves.

10. The automatic injection pen according to claim 1, characterized in that: The retracting sleeve comprises a sleeve body, and a connecting tube with a smaller outer diameter is connected to the bottom of the sleeve body of the retracting sleeve; the lower part of the connecting tube of the retracting sleeve is an elastic needle-retracting fixing claw, the outer protrusion at the bottom of the needle-retracting fixing claw forms a needle-retracting fixing hook, and the upper part of the needle-retracting fixing hook has a needle-retracting guide; the interior of the needle-retracting fixing claw forms a push rod guide cavity, which matches the push rod tube; The bottom of the retracting sleeve forms a step plane, the upper part is a needle-retracting support surface, and the lower part is a top abutting plane of the needle-retracting spring.

11. The automatic injection pen according to claim 1, characterized in that: A narrow spring seat is arranged on the top of the injection spring bracket; two sides of the narrow spring seat extend downward to form a connecting arm, and the bottom of the connecting arm is connected to the retracting sleeve.

12. The automatic injection pen according to claim 11, characterized in that: The middle of the narrow spring seat of the injection spring bracket extends downward to form a slender spring positioning column, and the spring positioning column is inserted into the inner side of the injection spring.

13. The automatic injection pen according to claim 1, characterized in that: The needle-retracting spring base has a spring cylinder, and the needle-retracting spring is sleeved on the spring cylinder; the bottom of the spring cylinder extends outward to form an annular spring seat; the spring seat of the needle-retracting spring base is fixedly installed in the upper pen shell; The bottom of the needle-retracting spring abuts against the spring seat of the needle-retracting spring base; the top of the needle-retracting spring abuts against the bottom plane of the sleeve body of the retracting sleeve.

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