Automatic injection pen capable of slowing down injection speed

Abstract

Provided is an automatic injection pen capable of slowing down the injection speed, which comprises: a housing (4), wherein the housing is arranged along a longitudinal axis and has a proximal end and a distal end, a cavity for accommodating a syringe is provided in the housing, and the syringe comprises a syringe body (3) and a piston (32) arranged in the syringe body (3); an injection mechanism (5) comprising an injection push rod (6) sleeved on the bottom of the syringe body; and a driving mechanism (7) driving the injection push rod to move axially. An initial position of the injection push rod (6) maintains a preset spacing L from the piston (32). The injection push rod (6), when coming into contact with the piston (32), overcomes its static friction resistance; during the subsequent pushing process, the driving force only needs to be greater than the dynamic friction resistance of the piston (32).

Description

An automated injection pen that can slow down the injection speed Technical Field

[0001] This invention relates to the field of medical device technology, and more specifically, to an automatic injection pen that can slow down the injection speed. Background Technology

[0002] With explosive population growth and the urban siphon effect, medical resources are becoming increasingly scarce. The management of chronic diseases consumes a significant amount of medical resources, resulting in substantial economic costs. Society has placed higher demands on self-administered injection devices, expecting them to be as simple to operate as possible without requiring special training. Traditional injection devices typically require mastery of the needle angle and depth, involving manual injection, which can lead to variations in drug efficacy depending on the user's skill level. Furthermore, with advancements in pharmaceutical technology, more and more chronic diseases are treated with periodic dosing. Traditional injection methods are cumbersome and complex, and patients may forget the steps before each injection, preventing the medication from achieving its intended effect.

[0003] The emergence of automated injection devices has provided an effective solution to this problem. Users desire devices that are simple to operate, have high patient compliance, and provide multi-dimensional feedback during the injection process, such as auditory, visual, and tactile feedback. Patients can control the entire injection process by receiving feedback signals, reducing anxiety and increasing confidence. Simultaneously, the needle depth should be consistent and stable, requiring no patient adjustment, and the needle tip should not be exposed before or after injection to avoid causing fear. The injection process should eliminate the need for manual injection and the injection time should be reasonable. After injection, it should also have functions to prevent accidental contact and / or reuse. At the same time, people are increasingly concerned about personal privacy, placing higher demands on the miniaturization, portability, and usability of the products. How to achieve these functions and performance to meet market demands is currently attracting increasing attention from engineering and technical personnel.

[0004] The existing patent number 2023109385598 discloses an automatic injection pen, including a pre-filled syringe module, a guide groove at the guide sleeve, a wing-shaped structure corresponding to the guide groove at the injection push rod, a spring at the trigger sleeve, and a rib at the corresponding wing-shaped structure. When the injection pen is in use, the spring opens and causes the trigger sleeve to move downward. The triggering inclined surface of the rib pushes the wing-shaped structure so that the wing-shaped structure can slide in the guide groove, and the injection spring pushes the injection push rod to inject.

[0005] However, in order to ensure proper triggering, the pressure spring of this disposable automatic injection pen needs to overcome both the starting resistance of the triggering mechanism and the starting resistance of the rubber stopper in the glass tube. Therefore, the initial pressure spring force of the injection pen is often too large, resulting in an injection time that is too short and an injection speed that is too fast. An excessively fast injection speed will cause more pain to the user. Summary of the Invention

[0006] In view of this, the present invention proposes an automatic injection pen that can slow down the injection speed, including a housing 4, which is arranged along a longitudinal axis and has a proximal end and a distal end. The housing 4 has a chamber for accommodating a syringe, which includes a syringe body 3 and a piston 32 disposed within the syringe body 3. An injection mechanism 5 is disposed in the distal end accommodating chamber of the housing 4. The injection mechanism 5 includes an injection push rod 6 sleeved with the bottom of the syringe body 3 and a drive mechanism 7 for driving the injection push rod 6 to move axially. The injection push rod 6 initially maintains a preset distance L from the piston 32. When the triggering mechanism is activated, the drive mechanism 7 applies a driving force to the injection push rod 6 to accelerate its movement and accumulate kinetic energy. The injection push rod 6 overcomes the static friction resistance of the piston 32 when it contacts the piston with this kinetic energy. During the subsequent pushing process, the driving force only needs to be greater than the dynamic friction resistance of the piston 32 to complete the injection, thereby extending the entire injection time.

[0007] An automatic injection pen capable of slowing down injection speed includes a housing 4, which is arranged along a longitudinal axis and has a proximal end and a distal end. The housing 4 has a chamber for accommodating a syringe. The syringe includes a syringe body 3 and a piston 32 disposed within the syringe body 3. An injection mechanism 5 is disposed in the distal end chamber of the housing 4. The injection mechanism 5 includes an injection plunger 6 sleeved with the bottom of the syringe body 3 and a drive mechanism 7 for driving the axial movement of the injection plunger 6. The injection plunger 6 initially maintains a preset distance L from the piston 32. When the trigger mechanism is activated, the drive mechanism 7 applies a driving force to the injection plunger 6 to accelerate its movement and accumulate kinetic energy. The injection plunger 6 overcomes the static friction resistance of the piston 32 upon contact with this kinetic energy. During subsequent pushing, the driving force only needs to be greater than the dynamic friction resistance of the piston 32 to complete the injection, thereby extending the overall injection time.

[0008] Further, the auto-injector is provided with a stepped resistance system, and the stepped resistance system has: a starting resistance threshold F1 for the driving mechanism 7, a starting resistance threshold F2 for the piston 32, and a steady injection resistance threshold F3 for the piston 32, wherein F1<F3<F2 is satisfied; the auto-injector is further provided with a dynamic energy management system, which comprises: a pre-stroke acceleration section, an energy release section and a continuous control section, wherein the pre-stroke acceleration section is that when the driving force of the driving mechanism is greater than F1, the injection push rod 6 is released from the constraint of the driving mechanism 7 and accelerates to accumulate kinetic energy, the energy release section is that at the instant when the injection push rod 6 contacts the piston 32, the kinetic energy enables the instantaneous output force of the system to be greater than F2, and the continuous control section is that the driving force of the driving mechanism is maintained in the interval of F3 < driving force < F2. If no preset spacing is provided between the injection push rod 6 and the piston 32, the initial driving force requirement of the driving mechanism 7 in the pre-stroke acceleration section is reduced to be greater than the sum of F1 and F2, and the driving mechanism 7 in the energy release section and the continuous control section is greater than F3, resulting in a shorter injection time.

[0009] In some embodiments, the spacing between the injection push rod 6 and the piston 32 is 3-30 mm. An excessively long spacing will increase the length of the injection pen and cause an impact feeling during injection due to the excessively long spacing, while an excessively short spacing will result in a shorter injection time.

[0010] Further, by adjusting the spacing between the injection push rod 6 and the piston 32, the driving force of the elastic driving module in the pre-stroke acceleration section is greater than F1, and the driving force generated by the accumulated elastic potential energy in the continuous control section is maintained at F3 < driving force < F2, so that the moving speed of the piston 32 moves according to a preset speed.

[0011] Further, the elastic driving module is an injection spring. Since the driving force value of the spring has a linear relationship, the maximum compression force value can be reduced, and a smaller change rate is conducive to stable injection, facilitating better control of the driving force in the pre-stroke acceleration section and the driving force in the continuous control section. If the maximum compression force value is very large at the beginning, it is difficult to reduce the force value during the injection process and achieve a change rate as small as possible.

[0012] In some embodiments, the distance between the injection plunger 6 and the piston 32 is adjusted according to the difference between F2 and F3. When the distance between the injection plunger 6 and the piston 32 is reduced, the driving force of the drive mechanism 7 at the moment of contact between the injection plunger 6 and the piston 32 is greater than F2. At this time, the driving force of the drive mechanism 7 is the main force to overcome the starting resistance of the piston 32, and the kinetic energy of the injection plunger 6 is the auxiliary force, resulting in a relatively long injection time. When the distance between the injection plunger 6 and the piston 32 is increased, the injection plunger 6 has already accelerated for a period of time before contacting the piston 32, gaining a relatively large kinetic energy. At this time, the driving force of the drive mechanism 7 is less than F2. At this time, the kinetic energy of the injection plunger 6 is the main force to overcome the starting resistance of the piston 32, and the driving force of the drive mechanism 7 is the auxiliary force. The driving force of the drive mechanism 7 is closer to F3, thereby effectively prolonging the injection time and reducing injection pain.

[0013] In some embodiments, the syringe body 3 is sleeved with the needle protection sleeve 2. A needle is installed at the front end of the syringe body 3, and a mounting seat 31 protruding from the syringe body 3 is at the rear end. The mounting seat 31 abuts against the inner wall of the needle protection sleeve 2. The needle protection sleeve 2 can selectively shift axially relative to the housing 4 along the longitudinal axis. An injection mechanism 5 is provided at the end of the needle protection sleeve 2 away from the body.

[0014] In some embodiments, the injection push rod 6 has an axial receiving channel, the inner wall of which forms a continuous guide structure; the elastic drive mold is coaxially nested in the guide structure, and its compression deformation direction coincides with the motion axis of the injection push rod 6; through the constraint cooperation between the guide structure and the inner wall of the push rod, the elastic drive mold is pre-compressed and stores energy during the no-load stroke of the push rod, and the stored energy is converted into uniform propulsion force along the push rod axis.

[0015] In some embodiments, a spring frame 10 extends through the injection spring. The spring frame 10 includes a spring guide rod structure 1011 disposed in the middle of the spring frame 10 and spring arms disposed on both sides of the spring frame 10. A hook 1012 is provided at the top of the spring arm. The spring guide rod structure 1011 passes through the inside of the injection spring, such that one end of the injection spring abuts against the injection push rod 6 and the other end abuts against the spring frame 10. A guide sleeve 8 is sleeved on the outside of the spring frame 10. A platform structure 81 is provided on the upper part of the guide sleeve 8. Before the injection pen is used, the platform structure 81 engages with the hook 1012. A guide groove 82 is also provided on the guide sleeve 8. A wing-shaped structure 61 corresponding to the guide groove 82 is provided on the injection push rod 6. A contact sleeve is provided on the outer sleeve of the guide sleeve 8. The trigger sleeve 9 has its upper end abutting against the needle protection sleeve 2. The trigger sleeve 9 has a spring piece 91 at the platform structure 81. The inner wall of the spring piece 91 has a first protrusion 92 that abuts against the hook 1012. The trigger sleeve 9 has a rib 93 at the wing-shaped structure 61. The trigger sleeve 9 is covered with a return spring 11. When the injection pen is in use, the needle protection sleeve 2 pushes the trigger sleeve 9 downward. The spring piece 91 opens under the interaction of the first protrusion 92 and the hook 1012, causing the trigger sleeve 9 to move downward. The rib 93 pushes the wing-shaped structure 61, allowing the wing-shaped structure 61 to slide in the guide groove 82. The injection spring pushes the injection push rod 6 to inject, and at the same time, the spring frame 10 moves downward, ending the injection.

[0016] The beneficial effects of this invention: This invention proposes an automatic injection pen that can slow down the injection speed, including a housing 4. The housing 4 is arranged along a longitudinal axis and has a proximal end and a distal end. The housing 4 has a chamber for accommodating a syringe. The syringe includes a syringe body 3 and a piston 32 disposed within the syringe body 3. An injection mechanism 5 is disposed in the distal end accommodating chamber of the housing 4. The injection mechanism 5 includes an injection push rod 6 sleeved with the bottom of the syringe body 3 and a drive mechanism 7 for driving the axial movement of the injection push rod 6. The injection push rod 6 initially maintains a preset distance L from the piston 32. When the trigger mechanism is activated, the drive mechanism 7 applies a driving force to the injection push rod 6 to accelerate its movement and accumulate kinetic energy. The injection push rod 6 overcomes the static friction resistance of the piston 32 when it contacts the piston 32 with this kinetic energy. During the subsequent pushing process, the driving force only needs to be greater than the dynamic friction resistance of the piston 32 to complete the injection, thereby extending the overall injection time. Attached Figure Description

[0017] Figure 1 is an exploded view of the overall injection pen of the present invention.

[0018] Figure 2 is a cross-sectional view of the overall injection pen of the present invention.

[0019] Figure 3 is a magnified view (B) of Figure 2.

[0020] Figure 4 is a structural diagram of the guide sleeve of the automatic injection pen of the present invention, which can slow down the injection speed.

[0021] Figure 5 is a structural diagram of the spring frame of the automatic injection pen of the present invention, which can slow down the injection speed.

[0022] Figure 6 is a structural diagram of the trigger sleeve of the automatic injection pen of the present invention, which can slow down the injection speed.

[0023] Figure 7 is a cross-sectional view of the trigger sleeve of the automatic injection pen of the present invention, which can slow down the injection speed.

[0024] Key component symbols: 2. Needle protective sleeve; 3. Syringe body; 31. Mounting base; 32. Piston; 4. Housing; 5. Injection mechanism; 6. Injection plunger; 61. Wing-shaped structure; 7. Drive mechanism; 8. Guide sleeve; 81. Platform structure; 82. Guide groove; 9. Trigger sleeve; 91. Spring piece; 92. First protrusion; 93. Rib; 10. Spring frame; 1011. Spring guide rod structure; 1012. Hook; 11. Return spring. The following detailed embodiments will further illustrate the invention in conjunction with the above drawings. Detailed Implementation

[0025] Example 1:

[0026] As shown in Figures 1-3, an auto-injection pen capable of slowing injection speed comprises a housing 4, wherein the housing 4 is arranged along a longitudinal axis and has a proximal end and a distal end; a chamber for accommodating a syringe is provided in the housing 4, the syringe comprises a syringe body 3 and a piston 32 disposed in the syringe body 3, and an injection mechanism 5 is provided in the chamber at the distal end of the housing 4; the injection mechanism 5 comprises an injection push rod 6 sleeved on the bottom of the syringe body 3, and a driving mechanism 7 for driving the injection push rod 6 to move axially; the injection push rod 6 maintains a preset spacing L from the piston 32 at an initial position, after a trigger mechanism is started, the driving mechanism 7 applies a driving force to the injection push rod 6 to enable the injection push rod 6 to accelerate and accumulate kinetic energy, the injection push rod 6 breaks through the static friction resistance of the piston 32 by virtue of the kinetic energy when contacting the piston 32, and in the subsequent pushing process, the driving force only needs to be greater than the dynamic friction resistance of the piston 32 to complete injection, so that the whole injection time is prolonged. The auto-injection pen is provided with a stepped resistance system, and the stepped resistance system has: a starting resistance threshold F1 of the driving mechanism 7, a starting resistance threshold F2 of the piston 32, and a steady injection resistance threshold F3 of the piston 32, wherein F1<F3<F2 is satisfied; the auto-injection pen is further provided with a dynamic energy management system, which comprises: a pre-stroke acceleration section, an energy release section and a continuous control section, wherein the pre-stroke acceleration section refers to that when the driving force of the driving mechanism is greater than F1, the injection push rod 6 breaks away from the constraint of the driving mechanism 7 and accelerates to accumulate kinetic energy; the energy release section refers to that at the moment when the injection push rod 6 contacts the piston 32, the kinetic energy enables the instantaneous output force of the system to be greater than F2; the continuous control section refers to that the driving force of the driving mechanism is maintained in an interval of F3<driving force<F2. If no preset spacing is provided between the injection push rod 6 and the piston 32, the initial driving force requirement of the driving mechanism 7 in the pre-stroke acceleration section is reduced to be greater than the sum of F1 and F2, and the driving mechanism 7 in the energy release section and the continuous control section is greater than F3, resulting in shorter injection time.

[0027] The distance between the injection plunger 6 and the piston 32 is 3-30mm. An excessively long distance increases the length of the injection pen and causes an impact during injection. An excessively short distance results in a shorter injection time. Different distances are set depending on the situation. The distance between the injection plunger 6 and the piston 32 is adjusted based on the difference between F2 and F3. When the distance is reduced, the driving force of the drive mechanism 7 at the moment of contact between the injection plunger 6 and the piston 32 is greater than F2. In this case, overcoming the starting resistance of the piston 32 is primarily achieved through the driving force of the drive mechanism 7, with the kinetic energy of the injection plunger 6 serving as an auxiliary force, resulting in a relatively longer injection time. When the distance is increased, the injection plunger... Before the moment rod 6 contacts piston 32, the injection push rod 6 has already accelerated for a period of time and gained a relatively large kinetic energy. At this time, the driving force of the drive mechanism 7 is less than F2. At this time, the kinetic energy of the injection push rod 6 is the main force to overcome the starting resistance of piston 32, and the driving force of the drive mechanism 7 is secondary. The driving force of the drive mechanism 7 is closer to F3, thereby effectively prolonging the injection time and reducing injection pain. The elastic drive module is an injection spring. Since the driving force of the spring is linear, it can reduce the maximum compression force. The smaller rate of change is conducive to stable injection and makes it easier to better control the driving force of the pre-stroke acceleration section and the driving force of the continuous control section. If the maximum compression force is very large at the beginning, it is difficult to reduce the force value and the rate of change as small as possible during the injection process.

[0028] As shown in Figures 4-7, the syringe body 3 is sleeved with the needle protective sleeve 2. A needle is mounted on the front end of the syringe body 3, and a mounting seat 31 protrudes from the syringe body 3 at the rear end. The mounting seat 31 abuts against the inner wall of the needle protective sleeve 2. The needle protective sleeve 2 can selectively shift axially relative to the housing 4 along the longitudinal axis. An injection mechanism 5 is located at the end of the needle protective sleeve 2 away from the proximal end. The injection push rod 6 has an axial receiving channel, and its inner wall forms a continuous guide structure. The elastic drive mold is coaxially nested within the guide structure, and its pressure... The direction of the compression deformation coincides with the motion axis of the injection push rod 6; through the constraint cooperation between the guide structure and the inner wall of the push rod, the elastic drive mold is pre-compressed and stores energy during the no-load stroke of the push rod. The stored energy is converted into a uniform propulsive force along the push rod axis. A spring frame 10 passes through the injection spring. The spring frame 10 includes a spring guide rod structure 1011 disposed in the middle of the spring frame 10 and spring arms disposed on both sides of the spring frame 10. A hook 1012 is provided at the top of the spring arm. The spring guide rod structure 1011 passes through the inside of the injection spring, so that one end of the injection spring abuts against the injection push rod 6. The other end abuts against the spring frame 10; a guide sleeve 8 is sleeved on the outside of the spring frame 10, and a platform structure 81 is provided on the upper part of the guide sleeve 8. Before the injection pen is used, the platform structure 81 is engaged with the hook 1012. A guide groove 82 is also provided at the guide sleeve 8. A wing-shaped structure 61 corresponding to the guide groove 82 is provided at the injection push rod 6. A trigger sleeve 9 is sleeved on the guide sleeve 8. The upper end of the trigger sleeve 9 abuts against the needle protection sleeve 2. A spring piece 91 is provided at the trigger sleeve 9 corresponding to the platform structure 81. The inner wall of the spring piece 91 is provided with a first The protrusion 92 abuts against the hook 1012. The trigger sleeve 9 has a rib 93 corresponding to the wing-shaped structure 61. The trigger sleeve 9 is covered with a return spring 11. When the injection pen is in use, the needle protection sleeve 2 pushes the trigger sleeve 9 downward. The spring piece 91 opens under the interaction of the first protrusion 92 and the hook 1012, causing the trigger sleeve 9 to move downward. The rib 93 pushes the wing-shaped structure 61 so that the wing-shaped structure 61 can slide in the guide groove 82. The injection spring pushes the injection push rod 6 to inject, and at the same time the spring frame 10 moves downward, and the injection ends.

[0029] The beneficial effects of this invention are as follows: This invention proposes an automatic injection pen that can slow down the injection speed, comprising a housing 4. The housing 4 is arranged along a longitudinal axis and has a proximal end and a distal end. The housing 4 has a chamber for accommodating a syringe. The syringe includes a syringe body 3 and a piston 32 disposed within the syringe body 3. An injection mechanism 5 is disposed in the distal end accommodating chamber of the housing 4. The injection mechanism 5 includes an injection push rod 6 sleeved with the bottom of the syringe body 3 and a drive mechanism 7 for driving the axial movement of the injection push rod 6. The injection push rod 6 initially maintains a preset distance L from the piston 32. When the trigger mechanism is activated, the drive mechanism 7 applies a driving force to the injection push rod 6 to accelerate its movement and accumulate kinetic energy. The injection push rod 6 overcomes the static friction resistance of the piston 32 when it contacts the piston 32 with this kinetic energy. During the subsequent pushing process, the driving force only needs to be greater than the dynamic friction resistance of the piston 32 to complete the injection, thereby extending the overall injection time.

[0030] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. An auto-injector capable of slowing down the injection speed, comprising a housing arranged along a longitudinal axis and having a proximal end and a distal end, a chamber inside the housing for accommodating a syringe, the syringe comprising a syringe body and a piston inside the syringe body, the distal end of the housing accommodating a chamber having an injection mechanism, the injection mechanism comprising an injection plunger sleeved with a bottom of the syringe body, a drive mechanism driving the injection plunger to move axially, characterized in that: The initial position of the injection push rod is at a preset distance L from the piston. When the trigger mechanism is activated, the driving mechanism applies a driving force to the injection push rod to accelerate its movement and accumulate kinetic energy. The injection push rod breaks through the static friction resistance of the piston when it contacts the piston due to the kinetic energy. In the subsequent pushing process, the driving force only needs to be greater than the dynamic friction resistance of the piston to complete the injection.

2. An auto-injector pen capable of slowing the rate of injection as claimed in claim 1, wherein: The automatic injection pen is provided with a staged resistance system, which has a driving mechanism activation resistance threshold F1, a piston activation resistance threshold F2, and a piston smooth injection resistance threshold F3, where F1 < F3 < F2. The automatic injection pen is also provided with a dynamic energy management system, which includes a pre-travel acceleration section, an energy release section, and a continuous control section. In the pre-travel acceleration section, the driving force of the driving mechanism is greater than F1, and the injection push rod is accelerated and accumulates kinetic energy. In the energy release section, the kinetic energy makes the instantaneous output force of the system greater than F2 when the injection push rod contacts the piston. In the continuous control section, the driving force of the driving mechanism is maintained in the interval F3 < driving force < F2.

3. An auto-injector pen capable of slowing the rate of injection as claimed in claim 1, wherein: The distance between the injection push rod and the piston is 3-30 mm.

4. An auto-injector pen capable of slowing the rate of injection as claimed in claim 1, wherein: By adjusting the distance between the injection push rod and the piston, the driving force of the elastic driving module in the pre-travel acceleration section is greater than F1, the accumulated elastic potential energy in the continuous control section maintains the driving force in the interval F3 < driving force < F2, and the movement speed of the piston is according to the preset speed.

5. An auto-injector pen capable of slowing the rate of injection as claimed in claim 1, wherein: The elastic driving module is an injection spring.

6. An auto-injector pen capable of slowing the rate of injection as claimed in claim 4, wherein: According to the difference between F2 and F3, the distance between the injection push rod and the piston is adjusted. When the distance between the injection push rod and the piston is reduced, the driving force of the driving mechanism when the injection push rod contacts the piston is greater than F2, which overcomes the piston activation resistance, and the driving force of the driving mechanism is the main force, and the kinetic energy of the injection push rod is the auxiliary force. When the distance between the injection push rod and the piston is increased, the injection push rod accumulates energy before it contacts the piston, and the driving force of the driving mechanism is less than F2, which overcomes the piston activation resistance, and the kinetic energy of the injection push rod is the main force, and the driving force of the driving mechanism is the auxiliary force.

7. An auto-injector pen capable of slowing the rate of injection as claimed in claim 6 wherein: The injection push rod has an axial accommodation channel with a continuous guide structure on its inner wall. The elastic driving module is coaxially nested in the guide structure, and its compression deformation direction coincides with the movement axis of the injection push rod. The pre-compression energy accumulation of the elastic driving module in the empty stroke of the push rod is realized by the constraint and cooperation of the guide structure and the inner wall of the push rod, and the accumulated energy is converted into uniform propulsion along the push rod axis.

8. An auto-injector pen capable of slowing the rate of injection as claimed in claim 5, wherein: The injection spring is internally penetrated by a spring holder, the spring holder comprises a spring guide rod structure arranged in the middle of the spring holder and a spring arm arranged on both sides of the spring holder, the top end of the spring arm is provided with a hook, the spring guide rod structure penetrates the inside of the injection spring, so that one end of the injection spring abuts against the injection push rod and the other end abuts against the spring holder; the outside of the spring holder is sleeved with a guide sleeve, the upper part of the guide sleeve is provided with a platform structure, when the injection pen is used, the platform structure is connected with the hook, the guide sleeve is also provided with a guide groove, the injection push rod is provided with a wing-shaped structure corresponding to the guide groove, the guide sleeve is externally sleeved with a trigger sleeve, the upper end of the trigger sleeve abuts against the needle protection sleeve, the trigger sleeve is provided with a spring piece corresponding to the platform structure, the inner wall of the spring piece is provided with a first protrusion and abuts against the hook, the trigger sleeve is provided with a muscle position corresponding to the wing-shaped structure, the trigger sleeve is externally sleeved with a return spring, when the injection pen is used, the needle protection sleeve pushes down the trigger sleeve, the spring piece is opened under the interaction of the first protrusion and the hook and makes the trigger sleeve move downward, the muscle position pushes the wing-shaped structure so that the wing-shaped structure can slide in the guide groove, the injection spring pushes the injection push rod to inject, at the same time, the spring holder moves downward, and the injection is completed.

9. An auto-injector pen capable of slowing the rate of injection as claimed in claim 1, wherein: The injector body is sleeved with the needle protection sleeve, the front end of the injector body is provided with a needle, and the rear end is a mounting seat protruding from the injector body, the mounting seat abuts against the inner wall of the needle protection sleeve, the needle protection sleeve can be selectively axially displaced relative to the shell along the longitudinal axis, and the needle protection sleeve is provided with an injection mechanism away from the near end.

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