KR102694749B1 - Auto-injector - Google Patents

Abstract

An embodiment of the present invention provides an automatic drug injection device, comprising: a tubular housing forming an exterior; a drug container provided with a drug storage unit for storing a drug and a syringe needle capable of penetrating skin to inject the drug stored in the drug storage unit, and fixated to the tubular housing; an activation member slidably installed along the tubular housing and having a receiving hole formed in a sliding direction; a first elastic member for pressing the activation member in a base direction; a plunger activated by the movement of the activation member to press the drug in the drug container; a trigger module activating the plunger by the movement of the activation member; a locking member installed in the receiving hole of the activation member, and moving from a first position to a second position by the movement of the activation member to be fixated to the housing; and a flexible element allowing the proximal end to be spread outward in the radial direction when the locking member moves from the first position to the second position, wherein when the activation member moves to the initial position, the receiving hole of the activation member and the proximal end of the flexible element are locked together to finally lock the activation member.

Description

AUTO-INJECTOR

The embodiment relates to an automatic drug injection device.

In cases of chronic diseases such as diabetes that require continuous management, or acute attacks such as anaphylactic shock in allergy patients that require immediate response, autoinjectors that allow users to inject themselves without visiting a hospital are widely used.

A pen needle-type auto injector has been developed and is widely used, which can be carried around and inserted into an appropriate injection location, automatically inserting the needle into the muscle and automatically injecting the injection liquid by a spring or other device.

However, in the case of conventional auto injectors, there was a problem in that it was impossible to know whether the drug injection had started or whether the drug injection was complete. In addition, there was a disadvantage in that when the auto injector needle was pulled out from the user's body after the drug injection was complete, it was exposed to the outside.

To solve this problem, many auto injectors have been developed that have a structure that locks the injection needle after injection of the injection liquid is completed, or a feedback structure that can inform the injection status of the injection liquid.

Korean Patent No. 10-2059765 discloses a drug injection device having an automatic feedback mechanism.

Referring to FIG. 1, a drug delivery device (1) according to the prior art comprises a plunger rod (11) arranged to be biased toward the proximal end (3a), a plunger (13), a first elastic member, i.e., an energy accumulation member (15), which may be, for example, a spring, arranged to bias the plunger rod (11) in the proximal direction, a second elastic member or energy accumulation member (9) arranged to bias the drug delivery member cover (7) in the proximal direction, a tubular rotor (17) arranged to receive the plunger rod (11) and the first energy accumulation member (15), a tubular extension member (5) axially and rotationally fixed to the housing (3), a tubular operating member (17) arranged to receive a portion of the rear end cap (7) and the plunger rod (11) and referred to as a tubular rotor (17) hereinafter, and arranged to receive the first energy accumulation member (15). It further comprises a signal generating member (21) hereinafter exemplified as a U-shaped bracket, hereinafter referred to as a "U-bracket", and a rod (19). The exemplified drug delivery device (1) further comprises a drug container holder (23) and a drug container (25) provided with a needle (25a). The plunger (13) is arranged to travel within the drug container (25) by linear displacement of the plunger rod (11) to discharge the drug through the needle (25a).

The plunger rod (11), the tubular extension member (5), the tubular actuating member (17), the energy accumulating member (15) and the signal generating member (21) form an automatic feedback mechanism or simply a feedback mechanism for the drug delivery device (1). The feedback mechanism is arranged to notify the user of the start of the discharge of the drug from the drug container (25).

Before use, the plunger rod is positioned axially fixed in the initial position. When the drug delivery device is actuated, i.e. the user initiates drug delivery, the plunger rod is released from the initial position and is pushed proximally by the energy accumulating member. When the plunger rod is displaced by a distance corresponding to the distance required for initiation of drug release, the contact between the first section of the plunger rod and the signal generating member will cease. Accordingly, the plunger rod and the signal generating member are designed such that the axial overlap of the first section and the signal generating member at the initial position of the plunger rod is equal to or substantially equal to said distance. Accordingly, the first section only supports the signal generating member during the axial displacement of the plunger rod distance corresponding to the distance required for initiation of drug release. When the plunger rod is displaced by an amount corresponding to this distance, the signal generating member will bend radially inwardly without being biased in its radial direction. Thereby, the signal generating member will separate from the tubular extension member. Therefore, the signal generating element that was biased distally by the first energy accumulating element is no longer retained by the tubular extension element and will therefore be thrown toward the distal inner surface of the tubular extension element. This results in an audible "click" sound and also a tactile sensation to the user.

However, in the case of conventional automatic drug injection devices, the operating member for unlocking and operating the plunger rod and the member for locking the drug container holder after drug injection is completed are provided separately, which has the disadvantages of increasing the number of parts and complicating assembly.

Therefore, there is a need to develop an automatic drug injection device that is easy to assemble and has a simplified structure to reduce the number of parts.

United States Patent Publication No. US20050273054A1 Republic of Korea Patent No. 10-2059765

The embodiment aims to provide an automatic drug injection device capable of preventing secondary infection and injury by preventing movement of an activation member after completion of drug injection of the automatic drug injection device so as to prevent exposure of the injection needle.

The invention provides an automatic drug injection device comprising: a tubular housing forming an exterior; a drug storage unit storing a drug; a drug container fixed to the tubular housing, the drug container having a drug storage unit capable of penetrating the skin to inject the drug stored in the drug storage unit; an activating member slidably installed along the tubular housing and having a receiving hole formed in a sliding direction; a first elastic member pressing the activating member in a proximal direction; a plunger activated by movement of the activating member to pressurize a drug in the drug container; a trigger module activating the plunger by movement of the activating member; a locking member installed in the receiving hole of the activating member and moved from a first position to a second position by movement of the activating member and then fixed to the housing; and a flexible element whose proximal end is radially spread outward when the locking member is moved from the first position to the second position; wherein when the activating member is moved to an initial position, the receiving hole of the activating member and the proximal end of the flexible element are locked to finally lock the activating member.

In another aspect of the invention, an automatic drug injection device is provided, wherein the locking member and the tubular housing have locking elements, and when the locking member moves to the second position, the locking elements of the locking member and the tubular housing are engaged with each other.

As another aspect of the embodiment, an automatic drug injection device is provided, characterized in that the flexible element is formed in a tubular housing.

As another aspect of the present invention, an automatic drug injection device is provided, further comprising a drug holder for fixing a drug container to a tubular housing; wherein the flexible element is formed on the drug holder.

In another aspect of the present invention, an automatic drug injection device is provided, characterized in that the length of a receiving hole formed in an activating member is greater than or equal to the sum of the length of a locking member and the distance the locking member moves from a first position to a second position.

As another aspect of the embodiment, an automatic drug injection device is provided, characterized in that it further includes a fixing element for fixing the position of the locking element in a first position before the activating member activates the trigger module.

In another aspect of the present invention, an automatic drug injection device is provided, wherein the securing element is formed on a proximal end of a flexible element and a locking member, and is characterized by a concave portion in which the proximal end of the flexible element is secured.

In another aspect of the present invention, an automatic drug injection device is provided, characterized in that the securing element is a projection or a recess formed on a locking member, and a recess formed on a housing and configured to receive the projection of the locking member or a projection received in the recess of the locking member.

In another aspect of the present invention, an automatic drug injection device is provided, characterized in that the trigger module includes a trigger housing installed in a tubular housing and having a tubular body accommodating a plunger and a catch formed along an inner circumference at a distal end of the body, a second elastic member installed in the trigger housing and urging the plunger in a proximal direction, a plurality of trigger arms formed at a distal end of the plunger and locked to the catches of the trigger housing, and a safety pin module installed at the distal end of the tubular housing and inserted into the center of the trigger arms to radially urge the trigger arms to maintain initial locking of the plunger and the trigger housing.

The drug injection device provided by the embodiment is small and light, and has the advantage of reducing the number of parts, simplifying the structure, and miniaturizing the device by having a locking member mounted within the activating member to prevent exposure of the injection needle by locking the activating member after drug injection is completed.

Figure 1 is a drawing showing a drug injection device having an automatic feedback mechanism according to the prior art;
Figure 2 is an exploded view showing an automatic drug injection device according to the first embodiment;
Figure 3 is an exploded cross-sectional view showing an automatic drug injection device according to the first embodiment;
FIG. 4 is a cross-sectional perspective view showing the housing of the automatic drug injection device according to the first embodiment;
FIG. 5 is a perspective view showing an activation member of an automatic drug injection device according to the first embodiment;
FIG. 6 is a perspective view showing a locking member of an automatic drug injection device according to the first embodiment;
Fig. 7 is a cross-sectional view showing the initial state of the automatic drug injection device according to the first embodiment;
Figure 8 is a cross-sectional view showing the appearance of the automatic drug injection device according to the first embodiment at the start of trigger release.
Figure 9 is a cross-sectional view showing the appearance of the automatic drug injection device according to the first embodiment after the trigger is released.
Figure 10 is a cross-sectional view showing the appearance of the automatic drug injection device according to the first embodiment after drug injection is completed.
Figure 11 is a cross-sectional view showing the final locked state after the activation member of the automatic drug injection device according to the first embodiment returns to the initial position.
FIG. 12 is a cross-sectional view showing a locking member and a flexible element of an automatic drug injection device according to a second embodiment;
Fig. 13 is a perspective view showing a drug holder of an automatic drug injection device according to the second embodiment.
FIG. 14 is a drawing showing a locking member fixing element of an automatic drug injection device according to a third embodiment;
FIG. 15 is a drawing illustrating a locking member fixing element of an automatic drug injection device according to a fourth embodiment.

Hereinafter, embodiments will be described in more detail with reference to the drawings. However, the concept of the present invention may be implemented in many different forms and should not be limited to the embodiments disclosed herein; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete and will sufficiently convey the scope of the concept of the present invention to those skilled in the art.

As used herein, the term "proximal end" refers to that end of a drug delivery device from which drug release can be provided. Thus, it is that end of the drug delivery device that is tapered toward an injection or release site. This definition also extends to any internal or external component of the drug delivery device, i.e., the proximal end of any component is the end closest to the proximal end of the drug delivery device. The "distal end" is the end opposite the proximal end.

"Proximal direction" means the direction from the distal end to the proximal end along the central axis of the drug delivery device. "Distal direction" means the direction opposite to "proximal direction."

FIG. 2 is an exploded view illustrating an automatic drug injection device according to the first embodiment, FIG. 3 is an exploded cross-sectional view illustrating an automatic drug injection device according to the first embodiment, FIG. 4 is a cross-sectional perspective view illustrating a housing of the automatic drug injection device according to the first embodiment, FIG. 5 is a perspective view illustrating an activating member of the automatic drug injection device according to the first embodiment, and FIG. 6 is a perspective view illustrating a locking member of the automatic drug injection device according to the first embodiment.

An automatic drug injection device according to an embodiment comprises a drug storage unit (710) for storing a drug in a tubular housing (100) forming an exterior, and a drug container having an injection needle (720) capable of injecting the drug stored in the drug storage unit (710) by penetrating the skin, and the drug container is fixed by a drug holder (730). An activation member (200) and a first elastic member for pressing the activation member (200) in a proximal direction are installed on the proximal side of the drug container in the tubular housing (100), and a plunger (400) for pressing a drug and a trigger module (420, 500, 700, 800) for deactivating the plunger (400) and activating it by movement of the activation member (200) are installed on the distal side of the drug container.

As described above, the proximal end side of the tubular housing (100) includes an activating member (200) that is slidably installed in the axial direction, and a first elastic member (300) that presses the activating member (200) in the distal direction. The proximal end (210) of the activating member (200) is an open end, which is exposed outside the proximal end (110) of the tubular housing (100) before drug injection. On the other hand, the distal end (120) of the tubular housing (100) is not open, but is a closed end, which prevents a trigger module, which will be described later, from being separated from the tubular housing (100) after the trigger is released.

The plunger (400) is installed in a locked manner within the trigger housing (500), and when the trigger is released, the plunger (400) slides within the drug storage unit (710) and pressurizes the drug.

A second elastic member (600) is installed between the trigger housing (500) and the plunger (400), and the second elastic member (600) is installed in a compressed state so as to pressurize the plunger (400) in the proximal direction.

The plunger (400) is locked so that it does not move in the proximal direction even when pressure from the second elastic member (600) is applied until the activation member (200) slides distally to activate the automatic drug injection device.

A drug container (700) having a drug storage section (710) for storing a drug and an injection needle (720) for injecting the drug stored in the tubular housing (100) is installed in the tubular housing (100). The drug container (700) is maintained in a fixed position in the tubular housing (100) by the drug holder (700) regardless of movement of the activating member (200) or the plunger (400).

At this time, the proximal end of the plunger (400) is assembled in a state of being inserted into the drug storage unit (710) to a predetermined depth, so that when the second elastic member (600) presses the plunger (400), the plunger (400) moves in the proximal direction within the drug storage unit (710), and the drug is injected into the user's body through the injection needle (720).

The activation member (200) has a cap-shaped proximal end (210) and a contact surface at the end of the proximal end (210) that comes into contact with the user's skin. A hole is provided in the center of the contact surface, and when the activation member (200) is retracted, an injection needle (720) is exposed through the hole.

The activation member (200) further includes an activation arm (220) extending distally from the proximal end (210). An accommodation hole (222) is formed in the activation arm (220) to accommodate a locking member (900) to be described later.

The trigger module for locking and unlocking the plunger (400) is composed of a trigger (420) of the plunger (400), a trigger housing (500), a second elastic member (600), and a safety cap module (800), and the trigger module operates only when the safety pin (830) of the safety pin module (800) is released.

The plunger (400) has a plunger rod (410) that slides into a drug container (710) to be described later and injects a drug solution, and a plurality of trigger arms (420) that extend distally from a distal end of the plunger rod (410). The plurality of trigger arms (420) are formed at intervals from each other along the outer periphery of the distal end of the plunger rod (410), and a cavity is formed in the center of the trigger arms (420). A safety pin (830) of a safety pin module (800) to be described later is inserted into the cavity. An arrowhead-shaped locking protrusion (422) is formed at the distal end of the trigger arm (420).

The trigger housing (500) has a tubular body (510), and a ring-shaped catch (520) is formed along the inner surface of the body (510) on the distal end side.

A safety pin module (800) is coupled to the distal end of the tubular housing (100). The safety pin module (800) has a tubular body (810), a head portion (820) formed at the distal end of the tubular body (810), and a safety pin (830) protruding from the head portion (820) in a proximal direction and inserted into an inner cavity of the trigger arms (420).

The trigger housing (500) is fixed to the tubular housing (100), and the distal end of the trigger housing (500) is located within the safety pin module (800), i.e., within the tubular body (810).

The locking projection (422) of the trigger arm (420) is spread radially outward when the safety pin (830) is inserted, and is locked with the catch (520) of the trigger housing (500). The locking of the trigger housing (500) and the trigger arm (420) is not released unless the safety pin (830) of the safety pin module (800) is removed from the cavity between the trigger arms (420). At this time, it is preferable that the trigger arm (420) is elastically movable in the radial direction, and when the safety pin (830) is not inserted into the middle of the trigger arms (420), it is preferable that the protruding radius of the locking projection (422) is smaller than the inner diameter of the catch (520) of the trigger housing (500). Accordingly, when the safety pin (830) is removed, the trigger arm (420) moves to the original position, and the locking of the catch (520) and the locking projection (422) is easily released.

In addition, the tubular housing (100) is formed with a flexible element (130) that is contracted by a locking member (900) to be described later and then opens when the locking member (900) moves to a second position to lock the activating member (200). In addition, a locking element is provided for fixing the position of the locking member (900) when the locking member (900) moves to the second position by the distal movement of the activating member (200). In the first embodiment, the locking element is a hole (910) formed in the locking member (900) and a locking protrusion (142) formed in the tubular housing (100) and inserted into the locking hole (910).

At this time, the tubular housing (100) may further include a stop projection (144) in addition to the locking projection (142), and the stop projection (144) comes into contact with the distal end (920) of the locking member (900) to prevent the locking member (900) from moving further in the distal direction.

The locking member (900) is installed in the receiving hole (222) of the activating member (200) as described above, and moves together with the activating member (200) when the activating member (200) slides in the distal direction, and moves from the first position to the second position. When the locking member (900) is in the first position, the flexible element (130) is in a state of being contracted radially inward by the locking member (900), and when the locking member (900) moves to the second position, the proximal end thereof spreads radially outward. In order for the activating member (200) to return to the initial position while the locking member (900) is fixed in position by the locking element in the second position, it is preferable that the length of the receiving hole (222) formed in the activating member (200) is greater than or equal to the sum of the length of the locking member (900) and the distance that the locking member (900) moves from the first position to the second position.

Meanwhile, since the locking member (900) is fixed in the second position and does not move back to the first position, the proximal end of the flexible element (130) continues to be spread out radially outward.

When the activation member (200) is moved in the proximal direction by the restoring force of the first elastic member (300) and returns to the initial position, the proximal end of the flexible element (130) is inserted into the receiving hole (222) of the activation member (200), and even if a distal external force is applied to the activation member (200) thereafter, the activation member (200) is finally locked so as not to move due to the interference of the receiving hole (222) and the flexible element (130). Therefore, the injection needle (720) is no longer exposed after the drug injection is completed.

Fig. 7 is a cross-sectional view showing the initial state of the automatic drug injection device according to the first embodiment, Fig. 8 is a cross-sectional view showing the appearance of the automatic drug injection device according to the first embodiment at the start of trigger release.

As described above, when the activating member (200) moves distally, the activating arm (220) comes into contact with the head portion (810) of the safety pin module (830) and is pushed distally. At this time, the locking member (900) also begins to move distally together with the activating member (200), and the proximal end of the flexible element (130) of the housing (100) also gradually comes out of the locking member (900) and begins to spread outward in the radial direction.

The proximal end of the locking member (900) maintains contact with the proximal end of the receiving hole (222) while moving from the first position to the second position.

FIG. 9 is a cross-sectional view showing the appearance of the automatic drug injection device according to the first embodiment after the trigger is released.

When the activation member (200) reaches the distal final position, the safety pin (830) is released from the trigger arm (420) and the trigger module is activated. The safety pin (830) is removed and the locking projection (422) of the trigger arm (420) moves radially inward, easily releasing the locking with the catch (510) of the trigger housing (500).

In addition, when the activation member (200) reaches the distal final position, the locking member (900) accommodated in the accommodation hole (222) of the activation member (200) also reaches the second position, and the locking projection (142) of the tubular housing (100) and the locking hole (910) of the locking member (900) are locked with each other, and the position of the locking member (900) is fixed at the second position.

That is, when the activation member (200) reaches the distal final position, the locking projection (142) of the housing (100) is locked into the locking hole (910) of the locking member (900), and the locking of the trigger arm (420) of the plunger (400) and the trigger housing (500) is released.

The proximal end of the flexible element (130) of the housing (100) also completely escapes the locking member (900) and opens radially outward.

Figure 10 is a cross-sectional view showing the appearance of the automatic drug injection device according to the first embodiment after drug injection is completed.

The plunger (400) moves toward the base by the restoring force of the compressed second elastic member (600), and accordingly, the plunger (400) moves toward the base within the drug storage unit (710) and pressurizes the drug solution, which is injected into the user's body through the injection needle.

FIG. 11 is a cross-sectional view showing the final locked state after the activating member of the automatic drug injection device according to the first embodiment returns to the initial position.

The activation member (200) moves toward the base by the restoring force of the first elastic member (300) and returns to the initial position, but the locking member (900) installed in the receiving hole (222) is locked with the locking projection (142) of the housing (100) and maintains the second position. At this time, the distance between the distal end of the locking member (900) and the distal end of the receiving hole (222) becomes minimum, and the distance between the proximal end of the locking member (900) and the proximal end of the receiving hole (222) becomes maximum.

Accordingly, as the proximal end of the receiving hole (222) moves further in the base direction, the proximal end of the flexible element (130) of the housing (100) is further spread outward in the radial direction and inserted into the receiving hole (222) of the activating member (200).

Thereafter, even if the activation member (200) receives force in the distal direction, the flexible element (130) and the receiving hole (222) interfere with each other, thereby limiting the movement of the activation member (200), and preventing the injection needle (720) from being exposed to the outside.

FIG. 12 is a cross-sectional view illustrating a locking member and a flexible element of an automatic drug injection device according to a second embodiment, and FIG. 13 is a perspective view illustrating a drug holder of an automatic drug injection device according to the second embodiment.

Except that the flexible element (732a) is formed on the drug holder (730a) that secures the drug container to the housing (100a), the other components are the same as in the first embodiment.

The flexible element (732a) formed in the drug holder (730a) is also cut in a T-shape so that the proximal end spreads outward in a radial direction when the locking member (900) moves from the first position to the second position, and the proximal end is a free end and the distal end is a fixed end.

When the activating member (200) moves to the initial position, the proximal end of the flexible element (732a) of the drug holder (930a) is locked within the receiving hole (222) of the activating member (200), thereby finally locking the activating member.

FIG. 14 is a drawing illustrating a locking member fixing element of an automatic drug injection device according to a third embodiment.

As described above, when the activating member (200) moves in the distal direction, the locking member (900b) formed in the receiving hole (222) moves together with the activating member (200), and then the locking member (900b) is fixed to the second position. In order for only the activating member (200) to return to the initial position, the length of the receiving hole (222) must be longer than the length of the locking member (900b). Preferably, the length of the receiving hole (222) must be greater than or equal to the sum of the length of the locking member (900b) and the distance that the locking member (900b) moves from the first position to the second position.

Therefore, when the activation member (200) is in the initial position, the locking member (900b) is not fixed in the first position within the receiving hole (222) and may move around within the receiving hole (222). To prevent this, the third embodiment additionally provides a fixing element for fixing the locking member (900b) in the first position.

According to the third embodiment, the locking member (900b) has a recessed portion (930b) at a position where it comes into contact with the flexible element (130), and the flexible element (130) is inserted into the recessed portion (930b) to restrict movement of the locking member (900b). However, the recessed portion (930b) is not completely locked with the proximal end of the flexible element (130) to prevent movement of the locking member (900b), and the depth of the recessed portion (930b) is formed shallow so that the flexible element (130) can move out of the recessed portion (930b) when an external force is applied to the activating member (200).

FIG. 15 is a drawing illustrating a locking member fixing element of an automatic drug injection device according to the fourth embodiment.

The fourth embodiment also has a fixing element for fixing the locking member (900c) in the first position, but the formation position and shape of the fixing element are somewhat different from those of the third embodiment.

If the fixing element is a projection (930c) formed on the surface where the locking member (900c) comes into contact with the housing (100c), the housing (100c) has a concave portion (150c) that accommodates the projection (930c). At this time, even if the housing (100c) does not have the concave portion (150c), if the protruding height of the concave portion (150c) is higher than the gap between the locking member (900c) and the inner surface of the housing (100c), the locking member (900c) can be prevented from being disengaged from the first position due to interference between the projection (930c) and the housing (100c).

Claims (9)

A tubular housing forming the exterior;
A drug container having a drug storage compartment for storing a drug and an injection needle capable of injecting the drug stored in the drug storage compartment by penetrating the skin, and fixed to a tubular housing;
An activating member that is installed slidably along a tubular housing and has a receiving hole formed in the sliding direction;
A first elastic member for pressurizing the activation member in the direction of the base;
A plunger that is activated by movement of the activating member to pressurize the drug within the drug container;
A trigger module that activates the plunger by movement of the activation member;
A locking member installed in the receiving hole of the activation member and sliding in the distal direction by the movement of the activation member from the first position to the second position and then fixed to the housing; and
A flexible element comprising a proximal end that is radially outwardly opened when the locking member moves from a first position to a second position;
An automatic drug injection device characterized in that when the activation member moves to an initial position, the receiving hole of the activation member and the proximal end of the flexible element are locked to finally lock the activation member. In the first paragraph,
An automatic drug injection device, characterized in that the locking member and the tubular housing have locking elements, and when the locking member moves to the second position, the locking elements of the locking member and the tubular housing engage with each other. In the first paragraph,
An automatic drug injection device characterized in that the flexible element is formed in a tubular housing. In the first paragraph,
Further comprising a drug holder for fixing the drug container to the tubular housing;
An automatic drug injection device, characterized in that the flexible element is formed in a drug holder. In the first paragraph,
An automatic drug injection device, characterized in that the length of the receiving hole formed in the activation member is greater than or equal to the sum of the length of the locking member and the distance the locking member moves from the first position to the second position. In paragraph 5,
An automatic drug injection device, characterized in that it further comprises a securing element for fixing the position of the locking element in the first position before the activating member activates the trigger module. In Article 6,
An automatic drug injection device, wherein the anchoring element is formed in the proximal end of the flexible element and the locking member, and is characterized by a concave portion in which the proximal end of the flexible element is anchored. In Article 6,
An automatic drug injection device, characterized in that the securing element is a projection or recess formed on a locking member, and a recess formed on a housing and configured to receive the projection of the locking member or a projection received in the recess of the locking member. In the first paragraph,
An automatic drug injection device, characterized in that the trigger module comprises: a trigger housing installed in a tubular housing and having a tubular body accommodating a plunger and a catch formed along an inner circumference at a distal end of the body; a second elastic member installed in the trigger housing and urging the plunger in a proximal direction; a plurality of trigger arms formed at the distal end of the plunger and locked to the catches of the trigger housing; and a safety pin module installed at the distal end of the tubular housing and inserted into the center of the trigger arms to radially urge the trigger arms to maintain initial locking of the plunger and the trigger housing.