Autoinjector

Abstract

An autoinjector (1) is disclosed. The autoinjector comprises a main housing (10); and a cartridge assembly (30) disposed within the main housing (10). The cartridge assembly may comprise a cartridge (3) and a needle (40). A power pack (100) is disposed within the main housing (10) for moving the cartridge (31) and the needle (40) from the storage position to the injection position when actuated. The actuation unit (50) includes a cartridge container (52) and a needle cap (60) disposed between the cartridge container (52) and the main housing (10). The actuation unit (50) is operably coupled to the power pack (110) and is retractable from a first position to an actuation position for actuating the power pack. The needle cover (60) is extendable to an extended position covering the needle (40) when the cartridge (31) and the needle (40) are in the injection position. The helmet (20) is removable from a mounted position on the front end of the main housing (10) to expose a front portion of the actuation unit (50).

Description

Technical Field

[0001] The present invention relates to an automatic injector. Background Art

[0002] An auto-injector is a medical device for delivering medication. In particular, an auto-injector is generally configured for intramuscular or subcutaneous delivery of self-administration (or untrained administration) of an accurate dose of medication. An auto-injector can be used to deliver a range of medications, including emergency medications (e.g., epinephrine for allergic reactions) or conventional medications (e.g., medications for rheumatoid arthritis). An auto-injector generally has a multi-stage actuation sequence, which may include a needle penetration step and a dose delivery step, in which the needle is moved to the injection position to cause skin penetration, and in which the piston is actuated to discharge the medication from the cartridge within the auto-injector. The auto-injector may have a further needle protection stage, which makes the device safe after use by shielding the needle (e.g., by retracting into a needle cover or unfolding a needle cover). Although some auto-injectors may include a user-operated button (or other trigger), for ease of operation, the auto-injector may be activated by the user grasping the housing of the syringe and forcing the front portion of the syringe against the injection site. Many such auto-injectors require the removal of a safety pin at the rear end to allow activation, and are activated by pressing the needle shield at the front end against the injection site. Such auto-injectors have an activation process that is performed at opposite ends of the device. This two-end activation process may cause confusion to some users about which end to press against the injection site. Some auto-injectors have a safety cap that is removed at the front end, which may also damage the sterility barrier. It is possible that a user may remove the safety cap without intending to use the device at the time.

[0003] Although a variety of auto-injector devices are available, there is still a desire for improved or alternative auto-injectors that are simple and / or intuitive for the end user to operate, particularly to avoid foreseeable misuse where the user misunderstands which end is the needle end. There is also a desire for auto-injectors that incorporate safety features that, for example, can prevent accidental operation and / or make the auto-injector safe after use or in the event that the user wishes to restore the device to a safe state that is not in use (e.g., if the device is not in use while sterility is maintained, the front safety cap is replaced after the safety cap is removed). Further, since auto-injectors are typically single-use devices (which need to be safely disposed of as "sharps" clinical waste after use), it is advantageous to ensure that the auto-injector device is designed for efficient manufacturing and material use. Embodiments of the present invention seek to address one or more of these needs. Summary of the invention

[0004] According to a first aspect of the present invention, an automatic injector is provided, comprising: a main housing; a cartridge assembly, the cartridge assembly being arranged in the main housing and comprising a cartridge and a needle, the cartridge containing a drug; and a power pack, the power pack being arranged in the main housing, the power pack being used to move the cartridge and the needle from a storage position to an injection position relative to the main housing when actuated. The actuation unit comprises a cartridge container and a needle cover arranged between the cartridge container and the main housing, the actuation unit being operably connected to the power pack and being capable of being retracted from a first position to an actuation position relative to the main housing for actuating the power pack. Thereafter, when the cartridge and the needle are in the injection position, the needle cover can be extended to an extended position covering the needle. The safety cap can be removed from a mounting position on the front end of the main housing to expose a front portion of the actuation unit comprising the needle cover and the cartridge container.

[0005] The hard hat is arranged to press the locking arm against the actuation unit when the hard hat is in the installed position to lock the actuation unit from moving from the first position until the hard hat is removed. In particular, the hard hat may lock the actuation unit from retracting relative to the housing until the hard hat is removed. The hard hat may lock the actuation unit from moving to the actuation position.

[0006] Advantageously, embodiments of the present invention provide an arrangement in which the safety cap ensures that the auto-injector is locked to prevent accidental actuation whenever the safety cap is in place on the main housing. This includes, for example, when the device is initially supplied to the user, but also includes if the user removes and then replaces the safety cap without using the device in the case of a recappable safety cap. In other words, the auto-injector of an embodiment has an arrangement that makes it safe even by recapping the safety cap before the device has been actuated. Advantageously, the sterility of the needle / needle assembly is maintained after recapping. That is, the cartridge container, plunger / piston rod and cartridge form a sterile enclosure that is not affected by removing the safety cap.

[0007] In an embodiment, removal of the front safety cap is the only action necessary to change the device from safe to ready to fire (ready to unlock the actuation unit). After removing the safety cap, the actuation unit can be moved backward to activate the power pack to drive the cartridge and needle assembly forward to the injection site and drive the drug from the cartridge.

[0008] In an embodiment, the autoinjector maintains a sterile chamber around the needle independent of removal of the safety cap.

[0009] In an embodiment, the autoinjector is arranged to be operated only from the front end by removal of the safety cap (to unlock movement of the actuation unit to allow actuation of drug delivery) and in such a way that removal of the safety cap does not lose sterility of the needle so that the safety cap can be recapped without losing sterility.

[0010] It will be appreciated that the storage position refers to the pre-use configuration of the auto-injector. In other words, this is the configuration in which the auto-injector is supplied to the user. Thus, in the storage position, the needle may be completely contained within the housing or any other part exposed to the outside, such as the cartridge container or needle cover. In the storage position, the cartridge and needle may be retracted relative to the housing. The injection position is the position of the needle and cartridge when a dose of medication is delivered. In the injection position, the forward end of the needle has been advanced forwardly beyond the housing (beyond the outer envelope of the auto-injector) to penetrate the skin and allow the injection to be delivered.

[0011] The hard hat may include inwardly protruding structures, such as ribs, for pressing the locking arms against the actuation unit to lock the actuation unit from retracting from the first position until the hard hat is removed. Advantageously, the inwardly protruding structures of the hard hat may engage the locking arms radially inwardly of the outer surface of the main housing, so that the locking arms may be concealed to a certain extent to reduce the risk of a user obstructing their movement after removing the hard hat.

[0012] When the hard hat is in the installed position, the actuating unit of the main housing and the locking arm can be engaged in a locking manner. When the hard hat is removed, the actuating unit of the main housing and the locking arm can be free or biased to disengage the lock. In an alternative embodiment, the lock is engaged by a part connected to the housing, which is actuated by the hard hat in the installed position.

[0013] The actuation unit may include a groove or step forming structure in its outer surface.When the hard hat is in the installed position, the locking arm may be pressed into engagement with the groove or step forming structure by the hard hat.

[0014] In some embodiments, when the hard hat is removed, the locking arm is free or biased to open outwardly, leaving the engagement with the groove or step forming structure. In other embodiments, the locking arm is forced to leave the groove by a structure or an actuating unit on the hard hat.

[0015] The front portion of the actuation unit may have a circular cross section. The safety helmet may have a non-circular cross section, for example, an oval cross section (which may include an elliptical cross section). That is, the shape of the safety helmet is designed to have a major axis in cross section that is different from the vertical minor axis. The cross-sectional shape of the safety helmet may generally match the cross-sectional shape of the housing. By providing a circular profile of the front portion of the actuator, and providing the safety helmet with a non-matching oval (or similar shape), it is possible to ensure that the opening of the safety helmet is always larger than the front portion of the actuation unit, regardless of the axial orientation of the safety helmet. This advantageously reduces the risk of accidental actuation of the device during recapping.

[0016] The hard hat and the main housing may include mechanical cooperating features. These features may include detents to releasably mount the hard hat on the front end of the main housing. The oval (or other non-circular shape) of the hard hat and housing ensures that when the hard hat is recapped, the cooperating features that engage the locking arm(s) are properly aligned.

[0017] In some embodiments, the front end of the hard hat and the main shell have cooperating oval cross-sections. The cooperating cross-sections can provide a snug fit installation and re-closing of the front end of the hard hat and the main shell.

[0018] The hard hat can be configured to be removable from the front end of the main housing by translation without rotation. Visual and / or tactile features can be provided on the exterior of the hat to indicate the removal action of the hard hat.

[0019] The needle cover may include a through opening.The cartridge container may include a recess such that a front end portion of the locking arm extends through the opening in the needle cover and is pressed into engagement with the recess of the cartridge container.

[0020] In some embodiments, the autoinjector may include a first locking arm and a second locking arm arranged at diametrically opposed positions. As herein, the safety cap is arranged to press the first locking arm and the second locking arm against the actuation unit when the safety cap is in the installed position to lock the actuation unit from retracting from the retracted position until the safety cap is removed.

[0021] In some embodiments, the locking arm has a front end that is enlarged to protrude inwardly.

[0022] In an embodiment, the main housing includes a window opening. The main housing may further include a transparent window sheet inserted into the main housing to close the window opening. The forward-projecting locking arm may be formed integrally with the window sheet. The main housing may include a pair of diametrically opposed window openings. The transparent window sheet may be inserted into each window opening, and each window sheet may include a forward-projecting locking arm.

[0023] According to another aspect of the present invention, an automatic injector is provided, comprising: a main housing; a cartridge assembly, the cartridge assembly being arranged in the main housing and comprising a cartridge and a needle, the cartridge containing a drug; and a power group, the power group being arranged in the main housing, the power group being used to move the cartridge and the needle relative to the main housing from a storage position to an injection position when actuated. The power group comprises an inner body, an outer body, a spring and a piston rod, the inner body comprising at least one chuck arm being movable between a retracted position and an outwardly opened position. The inner body is arranged in the outer body and is movable between an unactuated position and a released position in the outer body. When the inner body is in the unactuated position, the outer body maintains at least one chuck arm of the inner body in engagement with the piston rod to maintain the storage position of the piston rod against the bias of the spring. When the inner body is in the released position, at least one chuck arm is free to move to an open position, thereby releasing the piston rod to move the cartridge assembly by the action of the spring. The needle cover is operably connected to the power group. The needle cover can be retracted from a first position to an actuation position relative to the main housing for actuating the power group by moving the inner body of the power group from an unactuated position to a release position. Thereafter, when the cartridge and the needle are in the injection position, the needle cover can be extended to an extended position covering the needle.

[0024] Advantageously, in embodiments, the arrangement of the power pack may provide increased compactness. Further, in embodiments, the inner body, spring and piston move rearwardly as a unit during activation. Such an arrangement may reduce the activation force of the autoinjector because the spring of the power pack is not compressed by the activation action (it is compressed within the power pack during assembly of the autoinjector and released from this state when activated).

[0025] A spring may be located between the piston rod and the inner housing.

[0026] The needle cover may include at least one hook that engages a catch included in the automatic injector to hold the needle cover in the first position. The catch may be disposed on the cartridge container. The needle cover may be disposed between the main housing and the cartridge container. In an embodiment, when the needle cover is retracted from the first position to the actuated position, the at least one hook is deflected by the outer body, thereby releasing the at least one hook from the catch.

[0027] At least one collet arm of the inner body and the rearward end of the piston rod may include cooperating tapered surfaces. When the at least one collet arm is in the retracted position and the inner body is in the unactuated position, these surfaces may cooperate.

[0028] The piston rod may be an integrally formed part.

[0029] The spring may be coiled around the piston rod. The spring may have opposite ends which are positioned against a spring shoulder of the piston rod and an underside of a collet of the inner body, respectively. The collet may include at least one collet arm.

[0030] In some embodiments, the inner body is movable rearwardly within the outer body between an unactuated position and a released position.The inner body, piston rod and spring may move as a unit.

[0031] The inner body may include a collet. The at least one collet arm may include at least three collet arms forming a collet.

[0032] According to another aspect of the present invention, an automatic injector is provided, comprising: a main housing; a cartridge container, the cartridge container being contained in the main housing; and a cartridge assembly, the cartridge assembly being disposed in the cartridge container. The cartridge assembly comprises a cartridge and a needle, the cartridge containing a drug and a stopper, the stopper being movable in the cartridge for dispensing the drug through the needle. A power group is disposed in the main housing, the power group comprising a piston rod for moving the cartridge and the needle from a storage position to an injection position relative to the main housing when actuated. A sealing ring is disposed around the neck of the cartridge and between the cartridge and the cartridge container.

[0033] Providing a sealing ring around the neck of the cartridge can enable a sterile chamber to be formed around the needle. Such positioning of the sealing ring can allow for improved lateral compactness. The sealing ring also helps to ensure the positioning of the forward end of the cartridge during actuation of the automatic injector.

[0034] The cartridge may include a septum. When the cartridge is in the storage position, the rear end of the needle may be spaced from the septum. When the cartridge is in the injection position, the rear end of the needle may be configured to have pierced through the septum.

[0035] The opening in the front end of the needle cover or cartridge container may include a sealing member, such as a membrane. In some embodiments, the membrane may be a porous filter membrane. Additionally or alternatively, the sealing member may be a gas permeable material. When the cartridge and needle are in the injection position, the sealing member may be pierced by the needle. In an embodiment, the sealing member and the sealing ring provide a sterile chamber in the cartridge container. The porous filter membrane or the gas permeable material may provide a sterilization barrier (e.g., the sterilization barrier allows atmospheric gas and / or sterilizing gas to pass through and prevents bacteria from passing through). For example, the gas permeable material that can be used may include a solid material (e.g., a polymer or silicone) that allows gas to pass through or a material with a porous structure. The pores of the material may be small enough to prevent substances that will damage sterility from passing through, such as bacteria, fungi or viruses. The filter membrane may, for example, include woven or non-woven materials, open-cell foam-based materials and paper.

[0036] In some embodiments, the sealing member at the opening in the front end of the needle cover or cartridge container can be non-porous (e.g., silicone rubber). In such embodiments, a separate gas permeable opening can be provided in the sealing member, and the sealing ring provides a sterile chamber within the cartridge container.

[0037] The cartridges of the embodiments described herein may be made of glass (or other inert materials). The cartridges may generally be cylindrical (having a tubular form with an opening in one or both ends). For example, the cartridge may be closed at one end by a pierceable septum, and at the other end, the cartridge may be equipped with a stopper (also referred to as a piston).

[0038] According to another aspect of the present invention, an automatic injector is provided, comprising: a main housing; a cartridge container, the cartridge container being disposed in the housing; a cartridge assembly, the cartridge assembly being disposed in the cartridge container and comprising a cartridge and a needle, the cartridge containing a drug; and a power group, the power group being disposed in the main housing, the power group being used to move the cartridge relative to the main housing from a storage position to an injection position when actuated. The power group is configured to drive a piston rod in the cartridge to drive the drug through the needle. The needle cover is operably connected to the power group. The needle cover can be retracted from a first position to an actuation position relative to the main housing for actuating the power group. Thereafter, when the cartridge and the needle are in the injection position, the needle cover can be extended to an extended position covering the needle. The needle cover can be located between the main housing and the cartridge container. The main housing includes a housing window, and the needle cover includes a needle cover window. When the needle cover is in the first position, the housing window and the needle cover window are aligned. When the needle cover is in the extended position, the solid body of the needle cover is viewed through the housing window. Thus, it should be understood that in the first position, the user can inspect the drug in the cartridge. Conversely, in the extended position, the window is blocked by the needle cover and provides a visual indication that the autoinjector has been activated.

[0039] The cartridge can be loaded into a cartridge sleeve. The cartridge sleeve can be used to connect the piston rod of the power group and the cartridge assembly. For example, such an arrangement helps to prevent or reduce accidental relative movement between the cartridge and the piston rod before actuating the automatic injector.

[0040] The cartridge sleeve may include a cartridge sleeve window. When the needle cover is in the first position, the housing window, the needle cover window and the cartridge sleeve window may be aligned.

[0041] Embodiments may include a needle cover spring. The needle cover can be extended to the extended position by the action of the needle cover spring. The needle cover spring may be longitudinally disposed between the needle cover and the power pack. The needle cover spring may further be disposed between the needle cover and a rearward portion of the cartridge container. The needle cover spring may be disposed around the cartridge container.

[0042] In some embodiments, when the needle cover is in the first position, and when the needle cover is in the extended position, the needle cover spring may be located behind the housing window. Advantageously, such an arrangement may avoid any obstruction to viewing through the window caused by the needle cover spring.

[0043] The main housing may be opaque. The housing window may be a through opening. The housing window may be filled with a transparent window sheet.

[0044] According to another aspect of the present invention, an automatic injector is provided, comprising: a main housing; a cartridge container; a cartridge assembly, the cartridge assembly being arranged in the cartridge container and comprising a cartridge and a needle, the cartridge containing a drug; and a power group, the power group being arranged in the main housing, the power group being used to move the cartridge assembly from a storage position to an injection position relative to the main housing when actuated. The needle cover is operably connected to the power group. The needle cover can be retracted from a first position to an actuation position relative to the main housing for actuating the power group. When the cartridge assembly is in the injection position, the needle cover can be extended to an extended position covering the needle. The needle cover is locked by a first locking assembly in a first position to prevent forward movement, and is locked by a second locking assembly in an extended position to prevent backward movement. The first locking assembly includes a fastener assembly between the needle cover and the cartridge container at the rear end of the needle cover and the cartridge container, and the fastener assembly is released when the needle cover moves to the actuation position. The second locking assembly includes an elastic member of the needle cover, and when the needle cover moves to the extended position, the elastic member pops up to exceed the edge (ledge) of the main housing.

[0045] Thus, embodiments of the present invention may utilize a needle cover having a relatively long axial length. In this way, the needle cover spring may be positioned, for example, behind any window in the main housing of the auto-injector. This may allow the front of the auto-injector to be narrowed to provide space for the window. The locking assembly (each locking assembly) in the embodiments may be opened by cooperating features on the power pack, which may provide an arrangement with reduced complexity and / or ease of manufacture (e.g., with reduced parts count).

[0046] The power group of the embodiment comprises an inner body, an outer body, a spring and a piston rod. The needle cover can be retracted from a first position to an actuated position relative to the main housing for actuating the power group by moving the inner body of the power group from an unactuated position relative to the outer body to a release position. When the inner body is in the release position, the spring can be released to drive the piston rod and drive the cartridge assembly to the injection position.

[0047] The catch assembly of the first locking assembly may include a hook disposed at a rear end of the needle cover. The hook may engage the first protrusion at the rear end of the automatic injector. The hook may engage the first protrusion at the rear end of the cartridge container. Alternatively, the hook may engage the first protrusion at the forward end of the power unit. The hook may be disposed on a resilient arm. When the needle cover moves to the actuated position, the resilient arm may be deflected to disengage the protrusion, thereby releasing the needle cover from the cartridge container so that the needle cover can move to the extended position.

[0048] In some embodiments, the autoinjector may include a needle cover spring disposed about the cartridge container and longitudinally between the needle cover and the power pack.

[0049] The needle cover may include a needle cover window for viewing the drug in the cartridge when the needle cover is in the first position. The needle cover spring may be located rearward of the window.

[0050] According to a further aspect of the present invention, an automatic injector is provided, comprising: a main housing; and a cartridge assembly, which is arranged in the main housing. The cartridge assembly comprises a cartridge and a needle, the cartridge containing a drug. A plunger member is arranged in the cartridge, and when moved forward, the plunger member forces the drug to be discharged through the needle. A power group is arranged in the main housing, and the power group is used to move the cartridge assembly from a storage position to an injection position relative to the main housing when actuated. The automatic injector comprises a cartridge sleeve and a cartridge container, the cartridge sleeve comprising a lip at the rear end, and the cartridge container is arranged in the main housing. The cartridge sleeve is arranged around the neck of the cartridge at the front end of the cartridge sleeve. The power group comprises a piston rod, which has a front end extending through the rear opening of the cartridge for engaging and moving the plunger member forward. The front end is included in the spherical portion of the piston rod, and the lip engages behind the spherical portion to connect the piston rod and the cartridge.

[0051] The cartridge sleeve and piston rod of the embodiment can advantageously allow a simplified connection between the cartridge and the power pack. For example, it can eliminate the need for a threaded fit or friction fit interface between the power pack and the piston of the cartridge. Further, this can enable the piston (which can also be referred to as the stopper) to have a simple uniform thickness. A piston of uniform thickness can provide improved drug stability and sealing.

[0052] The sealing ring may be compressed between the cartridge container and the neck of the cartridge.

[0053] The cartridge sleeve may be open along a portion of one side. The cartridge sleeve may include a front collar disposed around the cartridge, and the front portion of the cartridge extends through the collar. The front portion of the cartridge may include a septum.

[0054] According to a further aspect of the present invention, an automatic injector is provided, comprising: a main housing; a cartridge assembly, the cartridge assembly being arranged in the main housing and comprising a cartridge and a needle, the cartridge containing a drug; and a power group, the power group being arranged in the main housing, the power group being used to move the cartridge and the needle from a storage position to an injection position relative to the main housing when actuated; and a needle cover spring. The automatic injector further comprises an actuation unit, the actuation unit comprising a cartridge container and a needle cover arranged between the cartridge container and the main housing. The actuation unit is operably connected to the power group and can be retracted from a first position to an actuation position relative to the main housing for driving the power group. Thereafter, when the cartridge and the needle are in the injection position, the needle cover can be extended to an extended position covering the needle by the action of the needle cover spring. When the actuation unit is in the actuation position, the needle cover spring is compressed between a spring stopper fixed to the main housing and the needle cover, thereby biasing the actuation unit toward the front end of the main housing.

[0055] The rearward portion of the needle cover may have an enlarged cross-sectional profile. The rearward portion may define a cavity between the needle cover and the cartridge container. The needle cover spring may be compressed within the cavity. The interface between the rearward portion and the forward portion of the needle cover includes a step change in profile to define a rearward-facing seat for the forward end of the needle cover spring.

[0056] The spring stop may comprise a fixed inward projection protruding from the inner surface of the main housing. The inward projection may, for example, comprise one or more bosses or flanges.

[0057] The actuation unit may further comprise a forward facing spring seat. The forward facing spring seat may be provided on the cartridge container, for example, on a rearward portion of the cartridge container. The forward facing spring seat may, for example, comprise at least one outwardly protruding tab on the cartridge container. When the actuation unit is in the first position, the forward facing spring seat may support the needle cover spring.

[0058] When the starter unit is in the actuated position, the forward facing spring seat may be rearward of the spring stop. Thus, when the spring is compressed between the spring stop and the needle cover, the forward facing spring seat may disengage the needle cover spring. The rear end of the needle cover spring may rest on a structure connected to the housing or outer body of the power pack, thereby enabling the spring to be compressed during start-up. Advantageously, this provides a stable and predictable force contribution to the start-up force, and advantageously provides a force bias towards a stable unstarted phase.

[0059] Unless otherwise stated, each integer described may be used in combination with any other integer, as will be understood by those skilled in the art. Further, while all aspects of the present invention preferably "comprise" the features described in relation to that aspect, it is specifically contemplated that they may "consist of" or "consist essentially of" those features outlined in the claims. Furthermore, unless specifically defined herein, all terms are intended to be given their meanings as commonly understood in the art.

[0060] Although the invention has been described above, the invention extends to any inventive combination of the features set out above or in the following description or drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Embodiments of the present invention may be carried out in various ways and embodiments thereof will now be described by way of example only with reference to the accompanying drawings, in which: Figure 1 shows an exploded view of an automatic injector according to an embodiment; Figure 2A and Figure 2B Shown in its initial, pre-use state Figure 1 Orthogonal side and cross-sectional views of an automatic injector; Figure 3A and Figure 3B Shown in a ready-to-actuate state Figure 1 Orthogonal side and cross-sectional views of an automatic injector; Figure 4A and Figure 4B Shows the transmitting state Figure 1 Orthogonal side and cross-sectional views of an automatic injector; Figure 5A and Figure 5B Shown in final, post-use state Figure 1 Orthogonal side and cross-sectional views of an automatic injector; Figure 6 Shown is a diagram for use in an initial, pre-use state. Figure 1 An isolated view of the power pack used in the auto-injector; Figure 7 Shows the ready state Figure 6 An independent view of the power group; Figure 8 Shows the pressed / triggered state Figure 6 An independent view of the power group; Fig. 9 Shows the transmitting state Figure 6 An independent view of the power group; Fig.10 Shown in its initial, pre-use state Figure 1An isolated view of the power pack and actuation unit of the auto-injector; Fig.11 Shows the pressed / triggered state Fig.10 Power group and actuation unit; Fig.12 Shown in final, post-use state Fig.10 Power group and actuation unit; Fig.13 Shows Figure 1 Cross-sectional detail of the auto-injector; FIG. 14A to FIG. 14D A series of piston rods for use in the autoinjector of the embodiments are shown; Fig.15 shows an alternative configuration of a hard hat according to an embodiment; Fig.16 shows an alternative configuration of the main housing according to an embodiment; Fig.17 shows alternative configurations of actuation units and power units for use in embodiments; Fig.18A and Fig.18B shows an alternative configuration of a cartridge sleeve for use in the embodiments; and A to D of Figures 19 show a label arrangement for use in the embodiment. DETAILED DESCRIPTION

[0062] It can be noted that "forward" and "rearward" are used herein to conveniently refer to various aspects of the device with reference to its typical orientation in use. Therefore, it should be understood that forward can generally mean a surface, component or direction close to or facing the drug delivery end (e.g., needle end) of the device. Similarly, it should be understood that rearward can generally refer to a surface, component or direction away from the delivery end. However, it should be understood that such references are not intended to be limiting, and the device can take any orientation in use. References to circumferential, radial or axial directions can also be used herein as general geometric terms for orientation relative to the longitudinal axis of the automatic injector device (typically consistent with the longitudinal direction toward the needle end). However, such terms are not intended to be interpreted in a narrow or restrictive manner, and, for example, do not exclude that the components may have non-circular or irregular forms.

[0063] Figure 1An autoinjector 1 according to an embodiment of the present invention is shown in FIG. 5 . The autoinjector 1 comprises a main housing 10 closed by a cap 20 (also referred to herein as a safety cap). Within the main housing 10, the autoinjector comprises a cartridge assembly 30, an actuation unit 50 and a power group 100, the power group comprising a spring 130. The actuation unit 50 comprises a cartridge container 52, a needle cover 60 and a needle cover spring 70. The needle cover 60 is radially disposed between the cartridge container 52 and the main housing 10.

[0064] The autoinjector 1 comprises a main housing 10 formed by two main body shells 11 and 12, which are configured to snap together elastically during assembly of the device. The snap-fit ​​connection will typically be an irreversible engagement, so that the end user cannot disassemble the housing 10, and therefore cannot access the internal components of the autoinjector 1. The label (discussed further below) locks the two main body shells 11, 12 together by bridging the joint between them, providing increased strength, and making the main body shells 11, 12 more difficult to disassemble. Therefore, advantageously, the autoinjector can be supplied without a protective case or a carrying case. The main housing 10 has an elongated tubular profile, wherein the rear end is closed and the opening 14 is located at the forward end. Having a closed rear end helps to ensure that the autoinjector is intuitive to use, because the user can immediately recognize which end of the device to operate from. The cross-sectional profile of the housing 10 is generally oval. It will be appreciated that oval is widely used herein and can include an elliptical or super-elliptical cross section and allow the label to be attached to the main housing. The oval shape advantageously prevents rolling and thus accidental falling from a surface.

[0065] The main housing 10 can be made of injection-molded plastic material. The main housing can be opaque. One or more windows 15 can be formed in the side of the housing 10, for example in the form of a through opening. A transparent window sheet 16 can be inserted into the main housing 10 to close the window opening. In the embodiment shown, the window sheet has an annular form and includes two halves 16a, 16b, each of which is interconnected with the corresponding main body shell 11, 12 of the main housing 10. The window sheet also includes locking arms 17a, 17b of the forward projections that will be further described below. A safety helmet 20 (described in further detail below) is removably mounted on the front end of the main housing 10 and closes the front opening 14.

[0066] As will be explained below with reference to corresponding features, the interior surface of the main housing 10 may be provided with integrally formed features which project inwardly into the autoinjector 1 to provide cooperating structures for components of the actuation unit 50 or power pack 100. For example, these features may include ribs 17, flanges 18 and / or stops 13.

[0067] The cartridge assembly 30 is disposed within the main housing 10. The cartridge assembly supports a cartridge 31. The cartridge 31 is typically a glass drug container with a stopper 35 ( Figure 1 14 ) is movable to dispense the drug from the cartridge. The size of the cartridge 31 can be selected based on the dose or drug that the auto-injector is intended to deliver, and can be, for example, in the range of 0.3 mL to 2.5 mL, such as approximately 1 mL or 1.5 mL. As will be further described below with reference to FIG. 14 , in some embodiments, a single sized cartridge 31 can be used in several auto-injector configurations that deliver different volumes of the same drug and thus provide the option of delivering different single doses during use (when the delivered volume is lower, more volume of drug remains in the cartridge after use). The forward end of the cartridge 31 can be provided with a septum 32a (see Fig.13 ) is closed by an aluminum crimp cap 32, the septum being, for example, a bromobutyl septum, which seals the drug inside the cartridge. The septum 32a is pierceable, thereby allowing the penetration of a needle.

[0068] In front of the cartridge 31 , the cartridge assembly 30 includes a needle 40 which is carried by a needle guide 42 . Fig.13 4 shows a detailed cross section of the needle 40. The rear end of the needle 40 protrudes beyond the needle guide 42, toward the septum 32a of the cartridge 31. The needle guide 42 is aligned relative to the forward end of the cartridge 31 by a guide sleeve 44, which is sized to seat on the shoulder of the crimp cap 32 of the cartridge 31. A sealing ring 46 is positioned between the guide sleeve 44 and the cartridge 31 (and can pass over the crimp cap 32 during assembly of the autoinjector to be seated on the neck of the cartridge 31).

[0069] The cartridge assembly 30 further comprises a cartridge sleeve 38 which slides around the cartridge 31 during assembly. The rearward end of the cartridge sleeve 38 is provided with a lip 39 which is located on the rearward end (open end) of the cartridge 31. The lip 39 defines an opening at the rearward end of the cartridge assembly which has a reduced diameter compared to the inner diameter of the cartridge 31. The cartridge sleeve 38 is also provided with a window 37 in the form of a through opening so as to avoid obstructing viewing of the contents of the cartridge 31. The cartridge sleeve 38 is axially and rotationally connected to the piston rod 140 and therefore cannot rotate and obstruct the window. The piston rod 140 can move forward but not backward.

[0070] The power pack 100 is also disposed within the main housing 10 for moving the cartridge assembly 30 relative to the main housing 10 from a storage position to an injection position when actuated (as will be explained below). The power pack 100 comprises an inner body 110, an outer body 120, a spring 130 and a piston rod 140. The spring 130 stores energy for actuating the autoinjector 1, and when released, the energy is used to drive the piston rod 140 and the cartridge assembly 30 to the actuated position. The inner body 110 and the outer body 120 are configured to hold the spring 130 in a latched state and release the spring to activate the device. Figures 6 to 8 The assembled power pack 100 is shown in isolation and in various stages of operation.

[0071] The piston rod 140 is an integrally formed part. The piston rod 140 has a forward portion 141 that is configured to extend through the rear opening of the cartridge 31 and engage the piston 35. The engaging end of the forward portion 141 may have an enlarged or spherical head 142 for engaging the piston 35. The lip 39 of the cartridge sleeve 38 has an inner diameter opening that is smaller than the outer diameter of the head 142 of the piston rod. In this way, the lip 39 engages the rearward end of the head 142 and maintains the connection between the cartridge 31 and the piston rod 140. The rearward portion 146 of the piston rod 140 is circumferentially surrounded by the spring 130 (and the spring 130 and the piston rod 140 are generally coaxial). The flange 145 extends around the middle portion of the piston rod 140 and defines a separation between the forward portion 141 and the rearward portion 146. The rearward face of the flange 145 provides a spring shoulder against which the forward end of the spring 130 is mounted. The rearward end of the piston rod 140 includes a latch head 148 that can be engaged by the inner body 110 of the power pack 100 (as will be further described below).

[0072] The inner body 110 is a generally tubular, integrally formed part that generally surrounds the piston rod 140 and the spring 130 (the spring is radially intermediate the rod and the inner body). The forward end of the inner body 110 includes latch members 116a, 116b that provide a snap-fit ​​assembly feature between the power pack 100 and the actuation unit 50. The rearward end of the inner body 110 includes a collet 112. The collet 112 includes four collet arms 113 that are circumferentially distributed around the inner body 110, and each collet arm is a section of the collet 112. Each collet arm 113 extends rearwardly from a collar 114. The collar 114 has an oval cross-section that is generally conformal to the shape of the autoinjector 1 defined by the main housing 10 (and supports and aligns the outer body 120 relative to the inner body 110). The collar 114 includes a groove 115 that is configured to receive and retain a head 126 of a latch arm 125 (described further below) of the outer body 120 .

[0073] As shown in Figures 2 and Figure 6 As best seen in the drawings, the shape of the collet 112 of the inner body 110 is designed and configured to engage and retain the latch head 148 of the piston rod 140. Specifically, the rearward end of each collet arm 113 includes a radially inwardly extending engagement surface that cooperates with the forward shoulder of the latch head 148 in the initial state of the device. Figure 6 14, it can be noted that the shoulder of the latch head 148 and the engaging surface of the collet arm 113 are provided with corresponding cooperating inclined surfaces 148a and 113a. Specifically, the inclined profiles of the cooperating surfaces 148a and 113a are angled forwardly and inwardly so that (as will be further described below) the latch head 148 can slide forwardly through the collet 112, thereby camming the collet arm 113 outwardly. The rearward end of the collet arm 113 further defines an annular, forward-facing surface on the underside of the collet 112. The forward-facing surface provides a spring shoulder against which the rearward end of the spring 130 is mounted. In the illustrated embodiment, there are four collet arms 113, two of which support the piston rod 140 and can release the piston rod when the collet is moved, while the other two collet arms 113 provide spring shoulders for the spring 130.

[0074] The outer body 120 is generally an oval tubular body and circumferentially surrounds the inner body 110 (so that it is intermediate between the inner body and the main housing). The outer body 120 can be regarded as a trigger member, which maintains the engagement between the collet 112 and the piston rod 140 in an initial position against the bias of the spring 130. As will be explained below, the relative axial movement between the inner body 110 and the outer body 120 can move the outer body 120 away from the alignment with the collet arm 113 to enable the collet to be disengaged. Since the outer body 120 is generally fixed relative to the main housing 10, the outer body 110 and the main housing 10 are provided with an interconnecting geometry to provide positive positioning between the two. For example, in the illustrated embodiment, the main housing 10 includes an internal flange 18, and when the automatic injector is assembled, the forward end of the outer body 120 abuts against the internal flange.

[0075] The forward end of the outer body 120 includes four radially outwardly extending tabs 122. The tabs 122 are arranged in two pairs on opposite sides of the outer body 120, with the tabs of each pair being circumferentially spaced apart. As will be explained below, the tabs 122 provide an interaction surface for the needle cover 60 to increase the robustness of the automatic injector and ensure accurate sequencing of spring release. The tabs 122 further act as a push rod to release the needle cover 60 because when the needle cover locking latch 64 (also referred to herein as a hook) is pressed against the tab, the arm 63 of the locking latch bends and releases the gripper on the tower 56 (also referred to herein as a boss) on the cartridge container 56.

[0076] The outer body 120 also includes two rearwardly extending latch arms 125. The latch arms 125 are diametrically opposed. Each latch arm 125 is a flexible, axially elongated member that is integrally formed with the outer body 120. The latch arm extends from a forward end that is continuous with the outer body 120 to a free rearward end that includes an inwardly protruding head 126.

[0077] The autoinjector 1 further comprises an actuation unit 50 comprising a cartridge container 52 , a needle cover 60 and a needle cover spring 70 . Figures 10 to 12 An isolated view of the actuation unit 50 and the power pack 100 is shown at different stages of operation. The cartridge container 52 is a generally tubular body configured to enclose the cartridge 31 and the cartridge assembly 30 (which includes the needle assembly 40). The forward end of the cartridge container 52 includes an opening 53, which is initially closed by a membrane 54. The cartridge assembly 30 is inserted into the cartridge container 52 from the opening at the rearward end. As shown in Fig.13 As best seen in the detailed cross-section of FIG. 5 , the sealing ring 46 of the cartridge assembly 30 can provide a seal between the exterior surface of the cartridge 31 and the interior surface of the cartridge container 52. By positioning the sealing ring 46 around the neck of the cartridge 31, not only a compact arrangement is provided, but also correct (coaxial) positioning of the leading end of the cartridge (with the assistance of the guide sleeve 44) within the cartridge container 52 is ensured.

[0078] The forward portion of the cartridge container 52 may form a chamber ( Fig.13 46). The chamber S in the automatic injector 1 extends axially from the membrane 54 to the sealing ring 46. Before starting the automatic injector 1, the needle assembly is completely contained in the chamber S to maintain the sterility of the needle assembly 40. The chamber S can have a gas permeable opening-for example, one or more of the membrane 54, the sealing ring 46 or the dedicated orifice can include a gas permeable material. With the sealed chamber S closed by the porous material, bacteria, viruses or fungi cannot enter the area around the needle assembly 40. However, the material is not a barrier to gases (including atmospheric gases). This arrangement allows the assembly to be sterilized using gases such as ethylene oxide during manufacturing. Although the illustrated embodiment uses a gas permeable membrane 54, other embodiments can provide alternative ways to maintain a sterile barrier in the cartridge container 52.

[0079] The rear portion of the cartridge container 52 provides an interface to enable interconnection between the actuation unit 50 and the power pack 100 . Figures 10 to 1210. The interconnection can be best seen in FIG. 10. In particular, the cartridge container 52 is provided with a pair of slots 55a and 55b that are configured to receive latching members 116a, 116b of the inner body 110 of the power pack 100. The slots 55a, 55b include forward ends with shoulders beyond which the latching features 116 can snap to couple the power pack 100 and the actuation unit 50. When the latching members 116 snap into place in the slots 55, the needle cover spring 70 is axially located between the inner side of the latch on the inner body 110 and the cartridge container 52 (e.g., see FIG. 10. Figures 10 to 12 ). As such, it will be noted that the needle cover spring 70 is located below the end of the latch member 116. This arrangement advantageously supports the latching configuration of the latch 116 and the slot 55 and blocks the latch member 116 from deflecting out of engagement once the autoinjector 1 has been assembled (and thereby enhances the robustness of the assembled connection between the power pack 100 and the actuation unit 50).

[0080] The rear end of the cartridge container 52 also includes a radially outwardly projecting boss 56. The bosses 56 are arranged in two pairs on opposite sides of the cartridge container 52, with the bosses of each pair being circumferentially spaced apart. As will be explained below, the bosses provide a fastener for the connection between the cartridge container 52 and the needle cover 60. Adjacent to the bosses 56, a forwardly facing seat 58 is also provided for receiving the rearward end of the needle cover spring 70.

[0081] The forward portion of the cartridge container 52 includes a pair of diametrically opposed external recesses 57a and 57b (or other step-forming features). The recesses are sized and shaped to receive and engage the enlarged, inwardly projecting free ends of the forwardly projecting locking arms 17a, 17b of the main housing 10. As will be further described below, in the initial configuration of the device, the recesses 57a, 57b (of which only 57b is in the Figure 1 ) and the ends of the locking arms 17a, 17b are axially aligned.

[0082] The needle cover 60 is also a generally tubular member and surrounds the cartridge container 52 from the outside so that the needle cover is disposed between the cartridge container 52 and the main housing 10. The needle cover includes a forward portion 61 that closely conforms to the outer contour of the cartridge container 52 with a small gap and a rearward portion 62 having an increased cross-sectional area. The contour of the rearward portion 62 provides an annular cavity around the cartridge container 52 that accommodates the needle cover spring 70 so that the spring is contained between the cartridge container 52 and the needle cover 60. The interface between the rearward portion 62 and the forward portion 61 of the needle cover 60 may include a step change in contour so that a rearward-facing seat 65 is defined for the forward end of the needle cover spring 70.

[0083] The needle cover 60, which is integrally formed with the rearward portion 62, includes four hooks 64, each of which is formed at the end of a rearwardly extending resilient arm 63. As will be further explained below, the hooks 64 form a first locking assembly which, in an initial configuration, engages the boss 56 of the cartridge container 52 to form a catch between the needle cover 60 and the cartridge container 52. The catch holds the needle cover in the first position against the forward bias of the needle cover spring 70. The needle cover spring 70 is initially compressed between the rearwardly facing seat 65 of the needle cover 60 and the forwardly facing seat 58 of the cartridge container 52. It may also be noted (particularly in Figure 2A and Figure 3B ), the rear end of the needle cover spring is also supported by the inwardly protruding stopper 13 of the main housing 10. In the initial (pre-use) configuration of the automatic injector 1, the stopper 13 and the forward-facing seat 58 are longitudinally aligned.

[0084] The needle cover 60 also includes a second locking assembly including a pair of diametrically opposed, outwardly extending resilient members 67a and 67b. Each resilient member 67 is integrally formed at a rearward portion of the forward portion 61 of the needle cover 60. The resilient members protrude outwardly and rearwardly from the forward end integral with the needle cover 61 to a free end 68. As will be further explained below, because the resilient members 67 are rearwardly angled, they can be cammed inwardly during forward movement to resiliently deflect the free ends 68 inwardly over features such as edges. Conversely, in the rearward movement, the free ends 68 of the resilient members will engage features such as edges and lock the needle cover 60.

[0085] The forward portion 61 of the needle cover 60 includes a pair of diametrically opposed through openings 66a, 66b. The openings 66a and 66b are axially and circumferentially aligned with the grooves 57a and 57b of the cartridge container 52. Thus, the locking arms 17a, 17b of the main housing 10 can each extend through a respective one of the through openings 66a, 66b to engage their respective grooves 57a, 57b.

[0086] The forward portion 61 of the needle cover 60 also includes a window 69 (typically a pair of diametrically opposed windows), which may be a through opening. Since the window 69 is in the forward portion 61 of the needle cover 60, it is forward of the needle cover spring 70. In the initial configuration of the autoinjector, the window 69 of the needle cover 60 is axially and circumferentially aligned with (or at least partially overlapped with) the window 15 of the main housing 10.

[0087] The cap 20 has an oval cross-section and a cup-like form with a closed front end 21 and an open rear end 22. One or more tactile features may be provided on the exterior of the cap 20 to allow the cap to be easily and intuitively grasped by the user. Advantageously, in the illustrated embodiment, the tactile features are three V-shaped ridges that both provide an additional grip and indicate the direction and action required to remove the hard hat 20. The oval cross-section of the hard hat has a shape that is complementary to the tapered front end of the main shell 10. The cap 20 and the main shell 10 are configured to provide a sliding fit that enables the front ends of the cap 10 and the main shell 10 to be installed and closed to cover the front opening 14. As shown in Figure 2B , Figure 3A and Figure 3B As best seen in FIG. 1 , a detent is provided to releasably mount the hard hat 20 on the front end of the main housing 10—for example, the interior surface of the cap 20 may include a protrusion 23 that engages a corresponding feature 19 (e.g., a protrusion 23) in the exterior surface of the main housing 10. Figure 2B as shown).

[0088] The cap 20 is configured internally to cooperate with the outer surfaces of the locking arms 17a, 17b of the main housing 10. In particular, the cap 20 may include inwardly protruding features, such as ribs 25a, 25b, which press the locking arms 17a and 17b radially inwardly against the actuation unit 50 so that the ends of the arms extend through the openings 66a, 66b of the needle cover 60 and engage the corresponding grooves 57a, 57b of the cartridge container 52. In this way, when the cap 20 is in place (e.g., installed) on the housing 10, the actuation unit 50 is locked in place relative to the housing 10.

[0089] The operation of the autoinjector 1 will now be described. FIG2 shows an initial configuration of the autoinjector pen (eg the configuration prior to use, such as being delivered to an end user) with the safety cap 20 attached to the forward end of the housing 10 . Figure 6 The corresponding configuration of the power pack 100 is shown in FIG. Fig.10 1 and 2 are shown in Figure 1. In this configuration, the ribs 25 of the cap 20 are forcing the locking arms 17 inward to lock the activation unit 50 relative to the housing 10. The needle cover 60 is latched to the power pack 100 by engagement of the first locking mechanism (the hook 64 engages the boss 56 of the cartridge container 52). In this position, the needle cover spring 70 is held in a compressed state with its forward end located on the rearwardly facing seat 65 of the needle cover 60 and its rearward end abutting against both the seat 58 of the cartridge container and the stopper 13 of the main housing 10.

[0090] like Figure 6As best seen in FIG. 1 , the power pack 100 (specifically, the inner body 110 thereof) is also initially in a latched configuration and is held against the forward bias of the spring 130. The latched state is maintained by the latch head 148 of the piston rod 140 held in the collet 112 of the inner body 110. The outer body 120 of the power pack 100 surrounds the collet 112 from the outside to resist its radial expansion (which would be required to release the head 148 of the piston rod 140).

[0091] It can be noted that the power pack 100 can also be provided with a safety pin 150 (such as Figure 6 As shown in FIG. 1 ), the safety pin mechanically blocks the movement between the inner body 110 and the outer body 120. The safety pin 150 can be inserted through an appropriate through hole in the main housing 10 (e.g., see FIG. Fig.19A 151 in the autoinjector 1. For example, such a safety pin can be used to ensure that the power pack cannot be accidentally released during assembly of the autoinjector 1. Once the autoinjector 1 is fully assembled (cap 20 attached), the safety pin 150 is no longer needed to isolate the power pack. In this way, the safety pin can be removed in one of the final assembly steps and before the autoinjector is packaged and delivered to the end user. The label 200 (discussed further below) is a hole through which the safety pin 150 extends to provide ingress protection and structural robustness.

[0092] In the initial configuration, the window 15 of the housing 10, the window 69 of the needle cover 60 and the window 37 of the cartridge sleeve 38 are aligned, and the cartridge container 52 is at least partially made of a transparent material. In this way, through the aligned windows 15, 69, 37 and the aligned transparent areas of the cartridge container 52, the user has an unobstructed view and can visually inspect the drug in the cartridge 31.

[0093] When it is desired to use the autoinjector 1, the user removes the cap by pulling the cap 20 axially away from the main housing 10. The stop features 19, 23 of the main housing 19 and cap 20 provide a slight resistance but can be easily overcome by the user. The ready-to-use configuration of the device is shown in FIG3 and Figure 7 2 shows the corresponding state of the power pack. It can be noted that, with the cap 20 removed, the forward end of the actuation unit 50 (which includes the forward portion of both the needle cover 60 and the cartridge container 52) extends forward of the opening 14 of the main housing 10. In this initial state, it can be noted that the needle assembly 40 is positioned so that the rearward needle tip is forward of the septum 32a, and the forward needle tip is rearward of the membrane, so that it is completely within the sterile chamber defined in the cartridge container 52.

[0094] With the cap 20 removed, the locking arms 17a and 17b are no longer held inwardly and can splay elastically outwardly so that the ends move out of engagement with the grooves 57a, 57b of the cartridge container 52. By this, the cartridge container is released and can move backwards to release the spring.

[0095] If the user chooses not to activate the autoinjector 1, removing the safety cap 20 from the housing 10 can be the opposite of repositioning the safety cap 20 on the autoinjector. This re-capping of the autoinjector 1 positions the ridges 25a, 25b back into engagement with the locking arms 17a and 17b so that they engage the grooves 57a, 57b. Thus, re-capping will make the autoinjector safe and lock the actuation unit 50 in place relative to the housing 10. The re-capping capability of the safety cap 20 is optional. Further, since the needle assembly 40 does not leave the sterile chamber S during the removal or replacement of the cap 20, the sterility of the device is maintained if the user uncovers the device without subsequent actuation.

[0096] To activate the autoinjector 1, the user grasps the main housing 10 and presses the front end of the device (the forward end of the actuation unit 50, e.g. the front end of the cartridge container / needle cover) against the injection site. The force on the front end causes the actuation unit 50 to move backward relative to the main housing 10. The locking arms 17a, 17b of the main housing 10 are no longer restrained inwardly and can be deflected outwardly, so that relative movement is not prevented. The cartridge container 52, needle cover 60 and needle cover spring 70 of the actuation unit are all moved backwards.

[0097] During the initial rearward movement of the actuation unit 50, the seat 58 of the cartridge container moves rearwardly away from the stopper 13 on the main housing 10. The seat 65 in front of the needle cover 60 moves longitudinally toward the stopper 13. The rearward end of the needle cover spring 70 cannot move past the stopper 13 and disengage from the seat 58. Therefore, the movement of the actuation unit 50 causes further compression of the needle cover spring 70 between the seat 65 and the stopper 13. Advantageously, this configuration helps to provide a reliable actuation force for the automatic injector (e.g., between 40% and 60% of the force may come from the spring).

[0098] In addition, compression of the needle cover spring 70 can be used to ensure that the autoinjector returns to a safe pre-use position (and can therefore be safely recapped) if it is not activated. Specifically, if the user only performs a partial activation movement (i.e., they do not depress the autoinjector 1 sufficiently to move the actuation unit 50 all the way to the activated position to initiate drug delivery) before removing pressure from the device, the needle cover spring 70 will act to return the actuation unit 50 to its pre-use or storage configuration by biasing the actuation unit 50 forwardly relative to the main housing 10 until the stop 13 and seat 58 are realigned.

[0099] Due to the connection between the inner body 110 of the power pack 100 and the cartridge container 52, the inner body of the power pack 100 also moves relatively backward with the actuation unit 50. The inner body 110 moves as a unit with the piston rod 140 and the spring 130. The outer body 120 of the power pack 100 is fixed relative to the main housing 10. The relative movement between the outer body 120 and the inner body 110 causes the collet 112 of the inner body 110 to move backward out of alignment with the surrounding portion of the outer body 120. This can be achieved in the embodiment of the present invention. Figure 8 and Fig.11 It can be clearly seen in the independent view of FIG. 1 that the inner body 110 extends rearwardly beyond the outer body 120.

[0100] As a result of the backward movement, the collet 112 is no longer restricted from expanding radially outward. Due to the forward force of the spring 130, the cooperating surface 148a of the latch head 148 is forced to bear on the corresponding cooperating surface 113a of the collet arm 113. The inclined surfaces of the cooperating surfaces 148a and 113a act to cam the collet arm 113 radially outward and release the latch head 148 of the piston rod 140. This allows the spring 130 to act freely and begin to push the piston rod 140 forward. In conjunction with this release of the piston rod 140, it can be noted that the head 126 of the latch arm 125 of the outer body 120 moves away from the groove 115 in the collar 114 of the inner body. This allows the latch arm 125 to snap inwardly in front of the collar 114. In this way, even if the user does not continue to maintain pressure on the main housing 10 of the automatic injector 1, the trigger configuration of the power unit 100 is maintained.

[0101] During activation, the relative rearward movement of the needle cover 60 also causes the release of the first locking assembly. The hook 64 of the needle cover 60 is pushed into engagement with the tab 122 of the outer body 120. This causes the resilient arms 63 carrying the hook 64 to be laterally resiliently deflected so that they move out of engagement with the boss 56. This causes the needle cover 60 to be unlocked and ready to be deployed under the forward force of the needle cover spring 70. However, at this stage, the needle cover 60 will not be deployed normally because the front end of the automatic injector 1 is still held in contact with the injection site.

[0102] As shown in Figure 4, after releasing piston rod 140, spring 130 pushes cartridge assembly 30 forward. Initially, this causes the forward end of needle to be pushed through porous filter membrane 54. When needle guide 42 reaches the inner front surface of the forward end of cartridge container 52, the rearward end of needle will pass through the diaphragm 32a of cartridge 30 to establish fluid passage after needle is fully extended. Once needle assembly 40 and cartridge 31 arrive in front of cartridge container 52, they may no longer move, and the force of spring 130 causes piston rod 140 to move stopper 35 forward in cartridge 31, and dose is applied via needle 40. When full dose has been applied, flange 145 of piston rod 140 reaches lip 39 of cartridge cover 38, and prevents further forward movement. Therefore, it should be understood that the position of flange 145 on piston rod 140 provides convenient features, which can be modified to provide an automatic injector that can deliver different volumes and therefore deliver different doses of medicine.

[0103] As shown in Figure 5 and Fig.12 As shown, once the injection is completed, the user can remove the automatic injector 1 from the injection site. Since the needle cover 60 is unlocked during the start-up and throughout the injection phase, the needle cover spring 70 can now act on the needle cover 60 and unfold the needle cover away from the forward end of the main housing 10, unless the front end of the automatic injector is manually held and forced not to unfold. When the needle cover 60 has been fully unfolded (it has been fully extended and the forward end of the cover exceeds the frontmost needle tip), the second locking assembly acts to lock the cover. The second locking assembly automatically acts because the outwardly extending elastic member 67 of the needle cover 60 passes over the inwardly extending rib 17 formed in the main housing 10. The angled arrangement of the elastic members 67 enables them to freely cam over the rib 17 during the forward movement of the cover 60 (under the force of the cover spring 70). Once beyond the rib 17, the elastic members 67 rebound to their outward positions. Therefore, the needle cover 60 is locked from moving backward because the elastic members cannot pass over the rib 17 in the opposite direction.

[0104] In this configuration, the autoinjector 1 cannot be reactivated and is safe because the needle 40 is completely covered by the cover 60. Due to the position of the needle cover, and because the window 15 of the main housing 10 is now blocked by a portion of the needle cover, the user can visually see that the autoinjector is no longer activated. Due to the forward extension of the needle cover 60, the user cannot replace the cap 20 on the main housing 10 (because the stop features 19, 23 of the main housing 19 and the cap 20 cannot be aligned). It can also be noted that the cross-sectional profile of the needle cover 60 is circular, while the cap 20 and the main housing 10 are both oval. This provides a useful visual indication to dissuade the user from attempting to re-cap the used device. Further, the geometry of the cap 20 and the main housing 10 can be selected to ensure that if an attempt is made to re-cap (before activation), the cap will not exert pressure on the needle cover (because it will only engage the larger oval profile of the main housing). After use, the needle cover 60 extends far beyond the main housing 10 and re-capping is impossible.

[0105] Figures 14A to 14D It is demonstrated how the autoinjector of the embodiments may be adapted to provide a variety of delivered doses by selecting an appropriate piston rod 140, without requiring modification of other aspects of the device. Fig.14A The piston rod 140 is as follows Figures 1 to 12 , and includes a single flange 145' at a central axial position that defines a separation between the forward portion 141 and the rearward portion 146 of the piston rod. The rearward face of the flange 145a provides a spring shoulder against which the forward end of the spring 130 is mounted. The forward face 145b of the flange 145 defines a stop surface that abuts the lip 39 of the cartridge sleeve 38 to prevent further forward movement of the piston rod relative to the cartridge 31 during drug delivery. Fig. 14B In the embodiment shown, the piston rod 140' has an increased axial spacing "x" between the forward face 145b' and the rearward face 145a'. In the illustrated arrangement, the additional axial spacing is provided by having two parallel spaced apart flange members 145' - however, it should be understood that a solid flange of increased axial thickness may have the same function. The rearward face 145a' may be positioned with respect to the Fig.14A The same axial position in the embodiment of the present invention is achieved so that the action of the spring 130 is not altered by the use of a modified piston rod 140'. Instead, the axially forwardly positioned forward face 145b' ensures that the piston rod 140 can enter the cartridge 31 to a reduced extent before being stopped by engagement between face 145a' and lip 39. This reduces the delivered dose provided by actuation of the autoinjector. Fig. 14C and Fig.14D Further variations are shown in Fig. 14BThe same as the embodiment of , but with increased axial spacing "y" and "z" which stops between the respective rearward faces 145a'', 145a''' and the respective forward faces 145b''', 145b'''. The greater the axial spacing, the lower the dose that will be delivered when the device is actuated - this enables the manufacture of a range of devices that use the same main component to deliver different doses, with only the piston rod changing (e.g. enabling a single production line to produce all syringes).

[0106] like 19A to 19D As shown, it will be noted that the autoinjector 1 is typically provided to the end user with the label 200 wrapped (and adhered) around the outer surface of the main housing 10. Fig.19A In the initially assembled configuration shown, the autoinjector 1 is unlabeled. In this arrangement, it should be noted that a number of apertures are present in the main housing 10. For example, aperture 151 at the rearward end of the housing 10 may include at least one opening for a safety pin 150 that prevents operation of the power pack during manufacturing. Further, aperture 155 may be provided at the forward end of the housing 10 and, for example, may be provided to assist in the flow of gas into the needle compartment S during sterilization of the autoinjector. Fig.19C As shown, the label 200 can be formed into a single web shape. The label has opposite sides 205, 206, a straight end 208 and a shaped forward end 210 to match the shape and configuration of the forward end of the automatic injector housing 10. It includes a pair of cutouts 201, 202, which are shaped and sized to match the window 15 of the housing 10. Fig.19D As can be seen, the label can be rolled up to form a tubular shape, wherein the sides 205 and 206 are adjacent and extend axially. In the rolled up configuration, the cutouts 201 and 202 are diametrically opposed. Fig.19B As shown, as a final step in assembling the autoinjector 1, the label 200 is wrapped around the housing 10 (and, for example, may be self-adhesive to adhere the label to a surface of the housing). With the label 200 in place, the openings 151, 155 of the housing 10 are covered, and in this way, the label 200 can provide inlet protection to the autoinjector 1. Since the main housing 10 is formed of two parts, the label 200 can also be arranged to cover the joint between the housing parts (for example, this can provide tamper protection and increased robustness).

[0107] Although aspects of the invention have been described above with reference to preferred embodiments, it will be appreciated that various changes or modifications may be made without departing from the scope of the invention as defined in the appended claims.

[0108] For example, it will be appreciated that the locking arrangement between the actuation unit 50 and the cap 20 may be formed in a variety of ways. Fig.15An alternative configuration is shown in the embodiment of FIG. In this arrangement, the cap 1520 is formed with a rearwardly protruding rib 1525 that forces or holds the locking arms 1517 in an outward direction to engage with the main housing 1510. When the locking arms 1517 are supported inwardly by the rib 1525, they cannot be compressed inwardly to ride over the inwardly protruding shoulder (or other such feature) of the housing. In this way, the cap 1520 blocks relative movement between the housing 1510 and the actuation unit 1550.

[0109] Fig.16 Another embodiment is shown in FIG. 1 , in which a locking arm 1617 is integrally formed as part of the main housing 1610. The locking arm 1617 may be formed as a forwardly extending tongue separated from adjacent portions of the housing by axially extending slots 1617a and 1617b to allow the forward end to be resiliently deflected. The cap in this embodiment may then be attached to the housing 1610 in the same manner as described above. Figure 1 to Figure 1 4, the locking arm 17 acts in the same manner against the forwardly extending tongue. Fig.17 An alternative arrangement of a first locking assembly is shown that holds the needle cover in the first (retracted) position. In this embodiment, hooks 1764 are radially outwardly oriented and provided on a pair of arms 1763 formed near the centerline of the rear portion of the needle cover 1760. The same arrangement can typically be provided on the opposite side of the automatic injector. Hooks 1764 engage bosses 1756 to lock the needle cover 1760 in place. It can be noted that in this embodiment, bosses 1756 are formed on the inner body 17110, rather than on the cartridge container 1752 (and, since the cartridge container 1752 and the inner body 17110 are fixed relative to each other, either component can include the bosses).

[0110] The outer body 17120 of the power pack 17100 includes cooperating cam surfaces 17122 that face the angled surfaces 1764a formed on the hook 1764. In use, it will be appreciated that relative movement between the needle cover 1760 and the outer body 17120 (i.e., during actuation of the autoinjector) will cause the angled surfaces 1764a to be engaged by the cam surfaces 17122. The cam surfaces 17122 squeeze the arms 1763 together and release the hook 1764 from engagement with the boss 1756 to release the needle cover 1760 for forward movement.

[0111] Fig.18A and Fig.18B An alternative cartridge sleeve 1838 is shown that may be used in embodiments. Fig.18A The cartridge sleeve 1838 is shown in its in-use configuration (ie, when assembled inside an auto-injector), and Fig.18BA pre-assembled configuration is shown. With a lip 39 open on one side to allow insertion of a cartridge 31 Figure 1 to Figure 1 In contrast to the embodiment of 1834, the cartridge sleeve 1838 is formed of two axially extending leg portions 1838a and 1838b connected at the forward end by an annular portion 1838c. The sides of the leg portions 1838a and 1838b are profiled to define a window 1837 therebetween when positioned around a cartridge. A lip 1839 is formed at the rear end of the cartridge sleeve 1838 by respective portions 1839a and 1839b and, like the lip 39 of the previous embodiment, will be located on the rear of the cartridge. Fig.18B As shown, the cartridge sleeve may have an initial configuration in which the legs 1838a and 1838b are open to allow easy insertion of the cartridge 31, and in use, the legs may be resiliently deflected together to close around the cartridge (and hold the enclosed cartridge holder 52 in place). Alternatively, the rest configuration of the sleeve 1838 may be as shown. Fig.18A As shown, the legs 1838a and 1838b can be elastically expanded to allow insertion of the cartridge 31 before springing back to the closed configuration.

[0112] Embodiments of the present invention may include features according to the following list of numbered statements (for the avoidance of doubt, these numbered statements are not claimed subject matter as defined in the appended claims): 1. An automatic injector, comprising: Main housing; a cartridge assembly disposed within the main housing and comprising a cartridge and a needle, the cartridge containing a medicament; a power pack disposed within the main housing, the power pack being operable, when actuated, to move the cartridge and the needle from a storage position to an injection position relative to the main housing; and an actuation unit comprising a cartridge container and a needle cover disposed between the cartridge container and the main housing, the actuation unit being operably coupled to the power pack and being retractable relative to the main housing from a first position to an actuation position for actuating the power pack and thereafter, when the cartridge and the needle are in an injection position, the needle cover being extendable to an extended position covering the needle; and A reclosable hard hat capable of being removed from a mounted position on the front end of the main housing to expose a front portion of the actuating unit, the hard hat being arranged to press a locking arm against the actuating unit when the hard hat is in the mounted position to lock the actuating unit from retracting from the first position until the hard hat is removed.

[0113] 2. The autoinjector of statement 1 wherein the safety cap includes ribs or other inwardly projecting structure for pressing the locking arm against the actuation unit to lock the actuation unit from retraction from the first position until the safety cap is removed.

[0114] 3. An autoinjector according to statement 1, wherein the actuation unit and the locking arms of the main housing are engaged in a locking manner when the safety cap is in the installed position, and the actuation unit and the locking arms of the main housing are free or biased to disengage the lock when the safety cap is removed.

[0115] 4. An autoinjector according to statement 1, wherein the actuation unit includes a groove or step forming structure in an outer surface thereof, and the locking arm is pressed into engagement with the groove or step forming structure by the safety cap when the safety cap is in the installed position.

[0116] 5. An autoinjector according to statement 4, wherein when the safety cap is removed, the locking arms are free or biased to open outwardly out of engagement with the recess or step forming structure.

[0117] 6. The autoinjector of statement 1, wherein the front portion of the actuation unit has a circular cross-section and the safety cap has an oval cross-section.

[0118] 7. The autoinjector of statement 1 wherein the safety cap and the main housing include mechanical cooperating features including a detent to releasably mount the safety cap on the front end of the main housing.

[0119] 8. The autoinjector of statement 1 wherein the safety cap and the front end of the main housing have cooperating oval cross-sections to provide a snug fit installation and recapping of the safety cap and the front end of the main housing.

[0120] 9. The autoinjector of statement 1 wherein the safety cap is removable from the front end of the main housing by translation without rotation.

[0121] 10. The autoinjector of statement 1 wherein the needle cover includes a through opening and the cartridge container includes a recess such that the forward end portion of the locking arm extends through the opening and is pressed into engagement with the recess of the cartridge container.

[0122] 11. An autoinjector according to statement 1, comprising first and second locking arms arranged in diametrically opposed positions, wherein the safety cap is arranged to press the first and second locking arms against the actuation unit when the safety cap is in the installed position to lock the actuation unit from retracting from the first position until the safety cap is removed.

[0123] 12. The automatic injector according to statement 1, wherein the locking arm has a front end which is enlarged to protrude inwardly.

[0124] 13. An automatic injector comprising: Main housing; a cartridge assembly disposed within the main housing and comprising a cartridge and a needle, the cartridge containing a medicament; a power pack disposed within the main housing, the power pack being operable, when actuated, to move the cartridge and the needle relative to the main housing from a storage position to an injection position; wherein the power pack comprises an inner body, an outer body, a spring and a piston rod, the inner body comprising at least one chuck arm movable between a retracted position and an outwardly extended position, the inner body being disposed within the outer body and movable within the outer body between an unactuated position and a released position, the outer body maintaining the at least one chuck arm of the inner body in engagement with the piston rod when the inner body is in the unactuated position to maintain the storage position of the piston rod against the bias of the spring, wherein when the inner body is in the released position, the at least one chuck arm is free to move to the extended position, thereby releasing the piston rod to move the cartridge assembly by the action of the spring; and A needle cover is operably connected to the power pack, the needle cover being retractable relative to the main housing from a first position to an actuated position for actuating the power pack by moving the inner body of the power pack from an unactuated position to a released position, after which the needle cover is extendable to an extended position covering the needle when the cartridge and the needle are in an injection position.

[0125] 14. The automatic injector of statement 13, wherein the spring is located between the piston rod and the inner housing.

[0126] 15. The autoinjector of statement 13, wherein the needle cover includes at least one hook that engages a catch included in the autoinjector to retain the needle cover in the first position.

[0127] 16. The autoinjector of statement 15, wherein the fastener is disposed on the cartridge container, and wherein the needle cover is disposed between the main housing and the cartridge container.

[0128] 17. The autoinjector of statement 16, wherein when the needle cover is retracted from the first position to the actuated position, the at least one catch is deflected by the outer body, thereby releasing the at least one catch from the catch.

[0129] 18. The autoinjector of statement 13, wherein the at least one collet arm of the inner body and the rearward end of the piston rod include matching tapered surfaces when the at least one collet arm is in the retracted position and the inner body is in the unactuated position.

[0130] 19. The autoinjector of statement 13, wherein the piston rod is an integrally molded part.

[0131] 20. The autoinjector of statement 13, wherein the spring is coiled around the piston rod and has opposing ends that are positioned against a spring shoulder of the piston rod and an underside of a collet of the inner body, respectively, wherein the collet includes at least one collet arm.

[0132] 21. The autoinjector of statement 13 wherein the inner body is movable rearwardly within the outer body between an unactuated position and a released position, and wherein the inner body, piston rod and spring move as a unit.

[0133] 22. The autoinjector of statement 13 wherein the inner body comprises a collet and the at least one collet arm comprises at least three collet arms forming the collet.

[0134] 23. An automatic injector comprising: Main housing; a cartridge container contained within the main housing; a cartridge assembly disposed within the cartridge container and comprising a cartridge and a needle, the cartridge containing a medicament and a stopper movable within the cartridge for dispensing the medicament through the needle; a power pack disposed within the main housing, the power pack including a piston rod for moving the cartridge and needle from a storage position to an injection position relative to the main housing when actuated; and A sealing ring is disposed around the neck of the cartridge and between the cartridge and the cartridge container.

[0135] 24. An autoinjector according to statement 23, wherein the cartridge includes a septum, and wherein when the cartridge is in the storage position, the rearward end of the needle is spaced from the septum, and wherein when the cartridge is in the injection position, the rearward end of the needle has pierced through the septum.

[0136] 25. An autoinjector according to statement 23, wherein the forward end of the needle cover or the opening in the cartridge container comprises a membrane which is pierced by the needle when the cartridge and needle are in the injection position.

[0137] 26. The autoinjector of statement 25, wherein the membrane is a porous filter membrane that provides a sterilization barrier that allows atmospheric gases to pass through and prevents bacteria from passing through.

[0138] 27. The automatic injector of statement 25, wherein the porous filter member and the sealing ring provide a sterile chamber within the cartridge container.

[0139] 28. The automatic injector of statement 23, wherein the cartridge is a vial made of glass.

[0140] 29. An automatic injector comprising: Main housing; a cartridge container disposed within the housing; a cartridge assembly disposed in a cartridge container and comprising a cartridge and a needle, the cartridge containing a drug; a power pack disposed within the main housing, the power pack being operable, when actuated, to move the cartridge from a storage position to an injection position relative to the main housing; and a needle cover operably coupled to the power pack, the needle cover being retractable relative to the main housing from a first position to an actuation position for actuating the power pack and thereafter, when the cartridge and needle are in an injection position, being extendable to an extended position covering the needle; wherein the needle cover is located between the main housing and the cartridge container, the main housing includes a housing window, and the needle cover includes a needle cover window, the housing window and the needle cover window are aligned when the needle cover is in the first position, and wherein the solid body of the needle cover is viewed through the housing window when the needle cover is in the extended position.

[0141] 30. The autoinjector of statement 29, wherein the cartridge is enclosed in a cartridge housing for coupling a piston rod of the power pack to the cartridge assembly, wherein the cartridge housing includes a cartridge housing window, wherein the housing window, the needle cover window, and the cartridge housing window are aligned when the needle cover is in the first position.

[0142] 31. The autoinjector of statement 29 including a needle cover spring, wherein the needle cover is extendable to the extended position by action of the needle cover spring, wherein the needle cover spring is disposed longitudinally between the needle cover and the power pack.

[0143] 32. The automatic injector of statement 31 wherein the needle cover spring is disposed about the cartridge container.

[0144] 33. The autoinjector of statement 31 wherein the needle cover spring is located rearwardly of the housing window when the needle cover is in the first position and when the needle cover is in the extended position.

[0145] 34. The autoinjector of statement 29 wherein the main housing is opaque and the housing window is through the opening.

[0146] 35. The automatic injector of statement 34, wherein the housing window is filled with a transparent window sheet.

[0147] 36. An automatic injector comprising: Main housing; Cartridge containers; a cartridge assembly disposed in a cartridge container and comprising a cartridge and a needle, the cartridge containing a drug; a power pack disposed within the main housing, the power pack being operable, when actuated, to move the cartridge assembly from a storage position to an injection position relative to the main housing; and a needle cover operably coupled to the power pack, the needle cover being retractable relative to the main housing from a first position to an actuation position for actuating the power pack, wherein the needle cover is extendable to an extended position covering the needle when the cartridge assembly is in the injection position; wherein the needle cover is locked by a first locking assembly in a first position to prevent forward movement, and is locked by a second locking assembly in an extended position to prevent backward movement; wherein the first locking assembly comprises a fastener assembly between the needle cover and the cartridge container at the rear ends of the needle cover and the cartridge container, the fastener assembly being released when the needle cover moves to the actuated position; and The second locking assembly includes an elastic member of the needle cover, and when the needle cover moves to the extended position, the elastic member pops up to exceed the edge of the main housing.

[0148] 37. An autoinjector according to statement 36, wherein the power pack comprises an inner body, an outer body, a spring and a piston rod, and wherein the needle cover is retractable relative to the main housing from a first position to an actuated position for actuating the power pack by moving the inner body of the power pack relative to the outer body from an unactuated position to a released position, wherein when the inner body is in the released position, the spring is released to drive the piston rod and drive the cartridge assembly to the injection position.

[0149] 38. The autoinjector of statement 36, wherein the catch assembly of the first locking assembly includes a hook disposed at a rearward end of the needle cover that engages the first protrusion at a rearward end of the cartridge container.

[0150] 39. An autoinjector according to statement 38, wherein the hook is disposed on a resilient arm which is deflected to disengage the projection when the needle cover is moved to the actuated position, thereby releasing the needle cover from the cartridge container to enable the needle cover to move to the extended position.

[0151] 40. The autoinjector of statement 36 including a needle cover spring disposed about the cartridge container and longitudinally between the needle cover and the power pack.

[0152] 41. The autoinjector of statement 36, wherein the needle cover includes a needle cover window for viewing the medicament in the cartridge when the needle cover is in the first position.

[0153] 42. The automatic injector of statement 41 including a needle cover spring located rearwardly of the window.

[0154] 43. An automatic injector comprising: Main housing; a cartridge assembly disposed within the main housing and comprising a cartridge and a needle, the cartridge containing a drug, wherein a piston member is disposed within the cartridge and, when moved forwardly, forces the drug to be expelled through the needle, wherein the piston member is disposed within the cartridge and, when moved forwardly, forces the drug to be expelled through the needle; a power pack disposed within the main housing, the power pack being configured to move the cartridge assembly from a storage position to an injection position relative to the main housing when actuated; a cartridge sleeve including a lip at a rearward end; a cartridge container disposed within the main housing; and Therein, the cartridge sleeve is arranged around the neck of the cartridge located at the front end of the cartridge sleeve, the power group includes a piston rod, the piston rod has a front end extending through the rear opening of the cartridge for engaging and moving the plunger member forward, and the front end is included in the spherical portion of the piston rod, and the lip is engaged behind the spherical portion to connect the piston rod and the cartridge.

[0155] 44. The automatic injector of statement 43, wherein the sealing ring is compressed between the cartridge container and the neck of the cartridge.

[0156] 45. The automatic injector of statement 43, wherein the cartridge sleeve is open along a portion of one side.

[0157] 46. ​​The autoinjector of statement 45 wherein the cartridge housing includes a front collar disposed about the cartridge and wherein the front portion of the cartridge extends through the collar.

[0158] 47. The automatic injector of statement 46, wherein the front portion of the cartridge comprises a septum.

[0159] 48. An automatic injector comprising: Main housing; a cartridge assembly disposed within the main housing and comprising a cartridge and a needle, the cartridge containing a medicament; a power pack disposed within the main housing, the power pack being operable, when actuated, to move the cartridge and the needle relative to the main housing from a storage position to an injection position; Needle cover spring; an actuation unit comprising a cartridge container and a needle cover disposed between the cartridge container and the main housing, the actuation unit being operatively coupled to the power pack and being retractable relative to the main housing from a first position to an actuation position for actuating the power pack, and thereafter, when the cartridge and the needle are in an injection position, the needle cover being extendable by the action of a needle cover spring to an extended position covering the needle; When the actuating unit is in the actuating position, the needle cover spring is compressed between the spring stopper fixed to the main housing and the needle cover, thereby biasing the actuating unit toward the front end of the main housing.

[0160] 49. The automatic injector of statement 48 wherein the needle cover includes a rearwardly facing spring seat for receiving a forward end of the needle cover spring.

[0161] 50. The autoinjector of statement 48 wherein the rearward portion of the needle cover has an enlarged cross-sectional profile to define a cavity between the needle cover and the cartridge container, the needle cover spring being compressed within the cavity.

[0162] 51. The autoinjector of statement 50 wherein the interface between the rearward and forward portions of the needle cover comprises a step change in profile to define a rearwardly facing seat for the forward end of the needle cover spring.

[0163] 52. The automatic injector of statement 48 wherein the spring stop comprises a fixed inward projection projecting from an inner surface of the main housing.

[0164] 53. The autoinjector of statement 52, wherein the actuation unit further comprises a forward facing spring seat, and wherein the forward facing spring seat supports the needle cover spring when the actuation unit is in the first position.

[0165] 54. The automatic injector of statement 54, wherein: When the starting unit is in the actuated position, the forward-facing spring seat is rearward of the spring stopper so that the forward-facing spring seat disengages the needle cover spring when the spring is compressed between the spring stopper and the needle cover.

[0166] 55. The automatic injector of statement 53 wherein the forward facing spring seat is located on a rearward portion of the cartridge container.

Claims

1. An automatic injector, comprising: Main housing; a cartridge assembly disposed within the main housing and comprising a cartridge and a needle, the cartridge containing a medicament; a power pack disposed within the main housing, the power pack being configured to move the cartridge and the needle from a storage position to an injection position relative to the main housing when actuated; as well as an actuation unit comprising a cartridge container and a needle cover disposed between the cartridge container and the main housing, the actuation unit being operably coupled to the power pack and being retractable relative to the main housing from a first position to an actuation position for actuating the power pack, and thereafter, when the cartridge and the needle are in the injection position, the needle cover being extendable to an extended position covering the needle; as well as a hard hat that can be removed from a mounted position on the front end of the main housing to expose a front portion of the actuation unit, the hard hat being arranged to press a locking arm against the actuation unit when the hard hat is in the mounted position to lock the actuation unit from retracting from the first position until the hard hat is removed Wherein, the needle cover includes a through opening and the cartridge container includes a recess, so that the front end portion of the locking arm extends through the opening and is pressed by the safety cap into engagement with the recess of the cartridge container.

2. The automatic injector according to claim 1, wherein: The hard hat includes a rib or other inwardly projecting structure for pressing the locking arm against the actuation unit to lock the actuation unit from retracting from the first position until the hard hat is removed.

3. The automatic injector according to claim 1, wherein: When the hard hat is in the mounted position, the actuation unit and the locking arm are engaged in a locking manner, and when the hard hat is removed, the actuation unit and the locking arm are free or biased to disengage locking.

4. The automatic injector according to claim 1, wherein: The cartridge container includes a recess in an outer surface thereof, and the locking arm is pressed into engagement with the recess when the safety cap is in the installed position.

5. The automatic injector according to claim 4, wherein: When the hard hat is removed, the locking arms are free or biased to expand outwardly out of engagement with the recesses.

6. The automatic injector according to claim 1, wherein: The front portion of the actuating unit has a circular cross-section, and the safety helmet has an oval cross-section.

7. The automatic injector of claim 1, wherein: The hard hat and the main shell include mechanical cooperating features including a detent to releasably mount the hard hat on the front end of the main shell.

8. The automatic injector of claim 1, wherein: The hard hat and the front end of the main housing have cooperating oval cross-sections to provide a snug fit installation and recapping of the hard hat and the front end of the main housing.

9. The automatic injector of claim 1, wherein: The hard hat is removable from the front end of the main housing by translation without rotation.

10. The automatic injector of claim 1, wherein: The safety cap is reclosable.

11. The autoinjector of claim 1 , comprising a first locking arm and a second locking arm disposed at diametrically opposed positions.

12. The automatic injector of claim 11, wherein: The safety cap is arranged to press the first and second locking arms against corresponding recesses of the cartridge container and extend through corresponding through openings of the needle cover when the safety cap is in the installed position to lock the actuation unit from retraction from the first position until the safety cap is removed.

13. The automatic injector of claim 1, wherein: The locking arm has a front end which is enlarged to protrude inwardly.

14. The automatic injector of claim 1, wherein: The main housing includes a window opening and further includes a transparent window piece inserted into the main housing to close the window opening, and wherein a forward-protruding locking arm is optionally formed integrally with the window piece, wherein the main housing includes a pair of completely opposite window openings, and a transparent window piece is inserted into each window opening, and wherein each window piece includes a forward-protruding locking arm.

15. The automatic injector of claim 1, wherein: The actuation unit comprises a sterile chamber for the needle, and removal of the safety cap does not affect the sterility of the sterile chamber.

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