Autoinjector

Abstract

An auto-injector 1 is disclosed. This auto-injector includes a main casing 10 and a cartridge assembly 30 disposed within the main casing 10. The cartridge assembly can include a cartridge 31 and a needle 40. A power pack 100 is disposed within the main casing 10 for moving the cartridge 31 and the needle 40 from a storage position to an injection position during operation. An actuating unit 50 includes a cartridge container 52 and a needle cover 60 disposed between the cartridge container 52 and the main casing 10. The actuating unit 50 is operably connected to a power pack 110 and is retractable from a first position for actuating the power pack to an actuating position. 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. A safety cap 20 is removable from an attachment position at the front end of the main casing 10 to expose the front portion of the actuating unit 50.

Description

Technical Field

[0001] The present invention relates to an autoinjector.

Background Art

[0002] An autoinjector is a medical device for delivering drugs. In particular, autoinjectors are generally configured for intramuscular or subcutaneous delivery to self-administer (or administer without training) an accurate dose of a drug. Autoinjectors can be used to deliver a variety of drugs, including emergency drugs such as epinephrine for anaphylaxis and prescription drugs such as drugs for rheumatoid arthritis. Autoinjectors generally have a multi-step actuation sequence that includes a needle insertion step of moving a needle to an injection position and piercing the skin, and a drug delivery (administration) step of actuating a piston to expel a drug from a cartridge within the autoinjector. The autoinjector can further have a needle protection step of securing the device after use by shielding the needle (e.g., by retracting it into a needle cover or deploying a needle cover). Some autoinjectors can include a button (or other trigger) that is operated by the user, but to facilitate operation, the autoinjector can be actuated by the user gripping the housing of the syringe and pressing the front portion of the syringe against the injection site. Many such autoinjectors require removal of a safety pin at the rear end to enable actuation and are actuated by pressing a needle shield located at the front end against the injection site. Such autoinjectors have an actuation process at the opposite end of the device. This dual-end actuation process can cause confusion for some users as to which end to press against the injection site. Some autoinjectors have a safety cap that is removed at the front end, which also breaks a sterile barrier. There is a possibility that the user may remove the safety cap when not intending to use the device at that time.

[0003] While various automatic injectors are available, there is a desire for improved or alternative automatic injectors that are easy and / or intuitive to operate for end-users, and that avoid foreseeable misuse, particularly where the user might misunderstand which end is the needle end. Also, automatic injectors are desired to incorporate safety features, for example, to prevent accidental operation and / or to make the automatic injector safe when it is desired to return the device to a safe state after use or when the user does not use the device (e.g., replace the front-end safety cap after removal if the device has not been used while sterility was maintained). Further, since automatic injectors are typically single-use devices (which need to be safely discarded as "sharps" medical waste after use), it is advantageous to ensure that the automatic 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, there is provided an automatic injector comprising a main casing, a cartridge assembly disposed within the main casing and including a cartridge containing a medicament and a needle, and a power pack disposed within the main casing that, when actuated, moves the cartridge and the needle from a storage position to an injection position relative to the main casing. The actuation unit comprises a cartridge container and a needle cover disposed between the cartridge container and the main casing, and is operatively coupled to the power pack and is capable of being retracted from a first position to an actuation position for actuating the power pack relative to the main casing. Thereafter, the needle cover is extendable to an extended position covering the needle when the cartridge and the needle are in the injection position. The safety cap is removable from an attachment position at the front end of the main casing, exposing the front portion of the actuation unit including the needle cover and the cartridge container.

[0005] The safety cap is arranged to press the locking arm against the actuating unit when the safety cap is in the attached position, locking the actuating unit so that it cannot move from the first position until the safety cap is removed. In particular, the safety cap can lock the actuating unit so that it does not retract relative to the casing until the safety cap is removed. The safety cap can lock the actuating unit so that it does not move to the actuated position.

[0006] Advantageously, embodiments of the present invention provide a configuration in which the auto-injector is always securely locked against unintentional actuation when the safety cap is in a predetermined position on the main casing. This includes, for example, not only when the device is first supplied to the user, but also in the case of a re-closable safety cap when the user removes the safety cap without using the device and then replaces it. In other words, the auto-injector of the embodiment has a configuration that can also be made safe by re-capping the safety cap before the device is actuated. Advantageously, the sterility of the needle / needle assembly is maintained even after re-capping. That is, the cartridge container, the plunger / piston rod, and the cartridge form a sterile housing that is not affected by the removal of the safety cap.

[0007] In an embodiment, the removal of the previous safety cap is the only action necessary to change the device from a safe state to an operable state (release the lock of the actuating unit). After removing the safety cap, the actuating unit can be moved rearward to activate the power pack, advance the cartridge and the needle assembly to the injection site, and deliver the drug from the cartridge.

[0008] In an embodiment, the auto-injector maintains a sterile chamber around the needle regardless of the removal of the safety cap.

[0009] In an embodiment, the auto-injector is configured to be operated only from the front end by removing a safety cap (to unlock the movement of the actuating unit to enable the operation of drug delivery), and the safety cap is configured to be re-capped without losing sterility so that the sterility of the needle is not lost by removing the safety cap.

[0010] It will be understood that the storage position means the configuration of the auto-injector before use. In other words, this is the configuration in which the auto-injector is supplied to the user. Therefore, in the storage position, the needle may be fully housed within the casing, or may be housed in other externally exposed components such as a cartridge container or a needle cover. In the storage position, the cartridge and the needle may be retracted relative to the casing. The injection position refers to the position of the needle and the cartridge when drug delivery (administration) is performed. In the injection position, the front end of the needle advances forward beyond the casing (beyond the outer wrapping of the auto-injector) and penetrates the skin to deliver the injection.

[0011] The safety cap can include a structure protruding inward, such as a rib, for pressing a locking arm against the actuating unit to lock the actuating unit against being pulled in from a first position until the safety cap is removed. Advantageously, the structure protruding inward of the safety cap may engage with a locking arm that is radially inward of the outer surface of the main casing, and in such a case, the locking arm may be somewhat hidden to reduce the risk of the user interfering with its movement after the safety cap is removed.

[0012] The locking arm of the actuating unit and the main casing can be lockably engaged when the safety cap is in the attached position. The locking arm of the actuating unit and the main casing may be in a free (not biased) or biased state so as to disengage from the lock when the safety cap is removed. In another embodiment, the lock is engaged by a component connected to a housing that is actuated by the safety cap being in the attached position.

[0013] The actuating unit can include a recess or a stepped formation structure on its outer surface. The locking arm may be pressed by the safety cap to engage with the recess or the stepped formation structure when the safety cap is in the attached position.

[0014] In some embodiments, the locking arm is free from engagement with the recess or stepped formation structure or is biased to spread outward when the safety cap is removed. In other embodiments, the locking arm is pushed out of the recess by a structure on the safety cap or the actuating unit.

[0015] The front portion of the actuating unit may have a circular cross-section. The safety cap may have a non-circular cross-section, for example, an oval cross-section (which may include an elliptical cross-section). That is, the safety cap has a shape with a major axis of a cross-section different from the perpendicular minor axis. The cross-sectional shape of the safety cap may generally match the cross-sectional shape of the casing. By making the front portion of the actuator circular and providing the safety cap with a non-matching oval (or similar shape) shape, the opening of the safety cap can always be larger than the front portion of the actuating unit regardless of the axial orientation of the safety cap. Thereby, the risk of the device accidentally operating during recapping is advantageously reduced.

[0016] The safety cap and the main casing may include a mechanism that mechanically cooperates. This mechanism may include a detent for releasably attaching the safety cap to the front end of the main housing. By making the safety cap and the casing oval (or other non-circular shape), the cooperating mechanism that engages with the locking arm is properly aligned when the safety cap is recapped.

[0017] In some embodiments, the front ends of the safety cap and the main casing have cooperating portions with an oval cross-section. The cooperating cross-sections enable attachment and recapping by sliding and fitting the front ends of the safety cap and the main casing together.

[0018] The safety cap may be configured to be removable from the front end of the main casing by translational movement without rotation. In order to indicate the removal operation of the safety cap, visual and / or tactile features may be provided on the outside of the cap.

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

[0020] In some embodiments, the auto-injector may include first and second locking arms disposed at diametrically opposed positions. As used herein, the safety cap is arranged to press against the actuating unit with the first and second locking arms when the safety cap is in the attached position, and locks the actuating unit against retraction 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 project inwardly.

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

[0023] According to another aspect of the present invention, there is provided an auto-injector comprising a main casing, a cartridge assembly disposed within the main casing and containing a cartridge containing a medicament and a needle, and a power pack disposed within the main casing for moving the cartridge and the needle from a storage position to an injection position relative to the main casing during operation. The power pack includes an inner body, an outer body, a spring and a piston rod, and the inner body includes at least one collet arm movable between a retracted position and an outwardly expanded position. The inner body is disposed within the outer body and is movable therein between a non-operating position and a release position. The outer body maintains at least one collet arm of the inner body in engagement with the piston rod and maintains the storage position of the piston rod against the biasing force of the spring when the inner body is in the non-operating position. At least one collet arm is free to move to an expanded position when the inner body is in the release position, thereby releasing the piston rod to move the cartridge assembly by the action of the spring. The needle cover is operatively coupled to the power pack. The needle cover is retractable from a first position to an operating position for actuating the power pack relative to the main casing by moving the inner body of the power pack from the non-operating position to the release position. The needle cover is then extendable to an extended position covering the needle when the cartridge and the needle are in the injection position.

[0024] Advantageously, in an embodiment, the arrangement of the power pack can enhance compactness. Further, in an embodiment, the inner body, the spring and the piston move rearward as a unit during activation. Such an arrangement can reduce the activation force of the auto-injector because the spring of the power pack is not compressed by the activation operation (compressed within the power pack during assembly of the auto-injector and released from this state during activation).

[0025] The spring can be disposed between the piston rod and the inner housing.

[0026] The needle cover may comprise at least one hook that engages with a fastener included in the auto-injector to hold the needle cover in a first position. The fastener may be disposed on the cartridge container. The needle cover may be disposed between the main casing and the cartridge container. In an embodiment, the at least one hook flexes by an outer body when the needle cover is retracted from the first position to an actuated position, thereby releasing the at least one hook from the fastener.

[0027] At least one collet arm of the inner body and the rear end of the piston rod can include mating tapered surfaces. The surfaces may mate when at least one collet arm is in a contracted position and the inner body is in a non-operated position.

[0028] The piston rod may be a one-piece molded part.

[0029] The spring may be wound around the piston rod. The spring may have opposing ends respectively disposed against a spring shoulder of the piston rod and under a collet of the inner body. The collet constitutes at least one collet arm.

[0030] In some embodiments, the inner body is movable rearward within the outer body between a non-operated position and a release position. The inner body, the piston rod, and the spring can move as a unit.

[0031] The inner body may comprise a collet. At least one collet arm may comprise at least three collet arms that constitute the collet.

[0032] According to another aspect of the present invention, there is provided an autoinjector comprising a main casing, a cartridge container housed within the main casing, and a cartridge assembly disposed within the cartridge container. The cartridge assembly includes a cartridge and a needle, the cartridge contains a drug, and includes a stopper movable within the cartridge for discharging the drug through the needle. A power pack is disposed within the main casing, and the power pack includes a piston rod for moving the cartridge and the needle from a retracted position to an injection position relative to the main casing during operation. A sealing ring is disposed between the neck portion of the cartridge and between the cartridge and the cartridge container.

[0033] By providing a sealing ring around the neck portion of the cartridge, a sterile chamber can be formed around the needle. Such positioning of the sealing ring can improve lateral compactness. The sealing ring also helps to ensure the positioning of the front end of the cartridge during operation of the autoinjector.

[0034] The cartridge may include a partition wall. The rear end of the needle may be spaced from the partition wall when the cartridge is in the retracted position. The rear end of the injection needle may be configured to penetrate the partition wall when the cartridge is in the injection position.

[0035] A seal member, such as a membrane, can be included in the opening at the front end of the needle cover or the cartridge container. In some embodiments, the membrane may be a porous filtration membrane. Additionally, or alternatively, the seal member may be a gas-permeable material. The sealing membrane may be penetrated by the injection needle when the cartridge and the injection needle are in the injection position. In an embodiment, the seal member and the sealing ring provide a sterile chamber within the cartridge container. The porous filtration membrane or the gas-permeable material can provide a sterilization barrier (e.g., allowing atmospheric gas and / or sterilizing gas to pass through while preventing the passage of bacteria). Gas-permeable materials that can be used may include, for example, solid materials that allow gas to pass through (e.g., polymers or silicones) or materials having a porous structure. The pores of the material may be small enough to prevent the passage of substances that compromise sterility, such as bacteria, fungi, viruses, etc. Examples of filtration membranes include woven or non-woven materials, open-cell foam materials, paper, etc.

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

[0037] The cartridge of the embodiments described herein may be made of glass (or other inert materials). The cartridge may generally be cylindrical (having a tubular form with openings at one or both ends). For example, one end of the cartridge may be closed by a penetrable partition, and the other end may be provided with a stopper (sometimes also referred to as a piston).

[0038] According to another aspect of the present invention, there is provided an autoinjector comprising: a main casing; a cartridge container disposed within the housing; a cartridge assembly disposed within the cartridge container and including a cartridge containing a drug and a needle; and a power pack disposed within the main casing, the power pack configured to move the cartridge from a storage position to an injection position relative to the main casing when actuated. The power pack is configured to drive a piston rod within the cartridge and drive the drug through the needle. A needle cover is operatively coupled to the power pack. The needle cover is retractable relative to the main casing from a first position to an actuation position for actuating the power pack. Thereafter, the needle cover is extendable to an extended position covering the needle when the cartridge and the needle are in the injection position. The needle cover is positioned between the main casing and the cartridge container. The main casing includes a casing window and the needle cover includes a needle cover window. When the needle cover is in the first position, the casing window and the needle cover window are aligned. When the needle cover is in the extended position, a solid body forming a rigid body of the needle cover is visible through the casing window. Thus, it will be understood that at the first position, the user can inspect the drug within the cartridge. On the other hand, in the extended position, the window is blocked by the needle cover, visually indicating that the autoinjector has been actuated.

[0039] The cartridge may be enclosed in a cartridge sleeve. The cartridge sleeve may serve to connect the piston rod of the power pack and the cartridge assembly. Such an arrangement may help to prevent or reduce an unintentional relative movement between the cartridge and the piston rod, for example, before actuation of the autoinjector.

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

[0041] The embodiment may include a needle cover spring. The needle cover may be extendable to the extended position by the action of the needle cover spring. The needle cover spring may be arranged longitudinally between the needle cover and the power pack. The needle cover spring may further be between the needle cover and the rear portion of the cartridge container. The needle cover spring may be arranged around the cartridge container.

[0042] In some embodiments, the needle cover spring may be located behind the casing window when the needle cover is in the first position and when the needle cover is in the extended position. Advantageously, such an arrangement can avoid the needle cover spring from obstructing the view through the window.

[0043] The main casing may be opaque. The casing window may be a through-opening. The window of the casing may be filled with a transparent window piece.

[0044] According to another aspect of the present invention, there is provided an auto-injector comprising a main casing, a cartridge container, a cartridge assembly disposed within the cartridge container and including a cartridge containing a medicament and a needle, and a power pack disposed within the main casing, the power pack being for moving the cartridge assembly from a storage position to an injection position relative to the main casing when actuated. A needle cover is operatively coupled to the power pack. The needle cover is retractable relative to the main casing from a first position to an actuating position for actuating the power pack. The needle cover is extendable to an extended position covering the needle when the cartridge assembly is in the injection position. The needle cover is locked against forward movement in the first position by a first locking assembly and against rearward movement in the extended position by a second locking assembly. The first locking assembly includes a fastening assembly between the needle cover and the rear end of the cartridge container that is released upon movement of the needle cover to the actuating position. The second locking assembly includes an elastic member of the needle cover that snaps over a ledge of the main casing when the needle cover is moved to the extended position.

[0045] Thus, in embodiments of the present invention, a needle cover having a relatively long axial length can be utilized. In this way, the needle cover spring can be disposed, for example, behind any window within the auto-injector main casing. Thereby, the front portion of the auto-injector can be made narrower to provide space for the window. The locking assembly (or each locking assembly) in the embodiments can be opened by a cooperating mechanism on the power pack, thereby providing a configuration with reduced complexity and / or ease of manufacture (e.g., reduced number of parts).

[0046] The power pack of the embodiment includes an inner body, an outer body, a spring, and a piston rod. The needle cover may be retractable relative to the main casing from a first position to an operating position for actuating the power pack by moving the inner body of the power pack relative to the outer body from a non-operating position to a release position. The spring may be released to drive the piston rod and drive the cartridge assembly to an injection position when the inner body is in the release position.

[0047] The latch assembly of the first locking assembly can include a hook disposed at the rear end of the needle cover. The hook can engage a first protruding portion at the rear end of the auto-injector. The hook can engage a first protruding portion at the rear end of the cartridge container. Alternatively, the hook can engage a first protruding portion at the front end of the power unit. The hook may be disposed on an elastic arm. The elastic arm can flex to disengage the engagement with the protruding portion when the needle cover is moved to the operating position, thereby releasing the needle cover from the cartridge container and allowing the needle cover to move to the extended position.

[0048] In some embodiments, the auto-injector can include a needle cover spring disposed longitudinally between the needle cover and the power pack around the cartridge container.

[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 disposed behind the window.

[0050] According to a further aspect of the present invention, there is provided an auto-injector comprising a main casing and a cartridge assembly disposed within the main casing. The cartridge assembly includes a cartridge and a needle, and the cartridge contains a medicament. A plunger member is disposed within the cartridge and, when moved forward, expels the medicament through the needle. A power pack is disposed within the main casing and, when actuated, is for moving the cartridge assembly from a retracted position to an injection position relative to the main casing. The auto-injector comprises a cartridge sleeve including a lip at its rear end and a cartridge container disposed within the main casing. The cartridge sleeve is disposed around the neck portion of the cartridge at the front end of the cartridge sleeve. The power pack includes a piston rod having a front end that extends through the rear opening of the cartridge to engage and move the plunger member forward. The front end is included in the bulbous portion of the piston rod, and the lip engages behind the bulbous portion to connect the piston rod and the cartridge.

[0051] The cartridge sleeve and piston rod of the embodiment can advantageously simplify the connection between the cartridge and the power pack. For example, it is possible to eliminate the need for a threaded or friction fit interface between the power pack and the piston of the cartridge. Further, this may enable the piston (sometimes also referred to as a stopper) to have a simple and uniform thickness. A piston of uniform thickness can improve the stability and sealing of the medicament.

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

[0053] The cartridge sleeve may be open along a part of one side surface. The cartridge sleeve is disposed around the cartridge and may include a front collar through which the front portion of the cartridge extends. The front portion of the cartridge can include a partition wall.

[0054] According to a further aspect of the present invention, there is provided an auto-injector comprising a main casing, a cartridge assembly disposed within the main casing and having a cartridge containing a medicament and a needle, a power pack disposed within the main casing for moving the cartridge and the needle from a storage position to an injection position relative to the main casing when actuated, a needle cover spring, and an operating unit including a cartridge container and a needle cover disposed between the cartridge container and the main casing. The operating unit is operatively coupled to the power pack and is retractable relative to the main casing from a first position to an operating position to actuate the power pack. Thereafter, the needle cover is extendable by the action of the needle cover spring to an extended position covering the needle when the cartridge and the needle are in the injection position. The needle cover spring is compressed between a spring stop fixed to the main case and the needle cover when the operating unit is in the operating position, thereby biasing the operating unit towards the front end of the main casing.

[0055] The rear portion of the needle cover may have an enlarged cross-sectional shape. The rear portion may define a cavity between the needle cover and the cartridge container. The spring of the needle cover may be compressed within the cavity. The interface between the rear portion and the front portion of the needle cover may include a stepped shape for defining a rearward-facing seat for the front end of the needle cover spring.

[0056] The spring stop may be constituted by a fixed inward protrusion protruding from the inner surface of the main casing. This inward protrusion may be constituted by, for example, one or more bosses or flanges.

[0057] The actuating unit may further include a forward spring seat. The forward spring seat may be provided on the cartridge container, for example, on the rear portion of the cartridge container. The forward spring seat may be constituted by, for example, at least one outwardly protruding tab on the cartridge container. The forward spring seat can support the needle cover spring when the actuating unit is in the first position.

[0058] The forward spring seat may be behind the spring stop when the actuating unit is in the actuated position. Therefore, when the spring is compressed between the spring stop and the needle cover, the forward spring seat may come off the needle cover spring. The rear end of the needle cover spring may rest on the casing of the power pack or on a structure connected to the outer body, allowing the spring to be compressed during operation. Advantageously, this provides a stable and predictable contribution of force to the actuating force, and advantageously, a stable biasing of force to the non-actuated stage.

[0059] Unless otherwise specified, each integer described can be used in combination with other integers as understood by those skilled in the art. Further, all aspects of the present invention preferably "comprise" the features described in connection with that aspect, but it is particularly contemplated that they "consist of" or "consist essentially of" the features outlined in the claims. Further, all terms are intended to be given the meaning generally understood in the art unless specifically defined herein.

[0060] The present invention has been described above, but the present invention extends to any inventive combination of the features described above or in the following description or drawings.

Brief Description of the Drawings

[0061] Embodiments of the present invention can be implemented in various ways, and the embodiments will be described by way of example only with reference to the accompanying drawings. FIG. 1 is an exploded perspective view of an auto-injector according to an embodiment. Figures 2A and 2B are orthogonal side and cross-sectional views of the autoinjector of FIG. 1 in its initial state before use. Figures 3A and 3B are orthogonal side and cross-sectional views of the autoinjector of FIG. 1 in a state where preparation for operation is complete. Figures 4A and 4B are orthogonal side and cross-sectional views of the autoinjector of FIG. 1 in a fired state. Figures 5A and 5B are orthogonal side and cross-sectional views of the autoinjector of FIG. 1 in its final state after use. Figure 6 shows an exploded view of the power pack used for the autoinjector of FIG. 1 in its initial, pre-use state. Figure 7 is an exploded view of the power pack of FIG. 6 in a state where preparation is complete. Figure 8 is an exploded view of the power pack of FIG. 6 in a state where it has been pushed down / triggered. Figure 9 is an exploded view of the power pack of FIG. 6 in a fired state. Figure 10 shows an exploded view of the power pack and the operating unit of the autoinjector of FIG. 1 in its initial state before use. Figure 11 shows the state where the power pack and the operating unit of FIG. 10 have been pushed down / triggered. Figure 12 shows the power pack and the operating unit of FIG. 10 in their final state after use. Figure 13 is a detailed cross-sectional view of the autoinjector of FIG. 1. Figures 14A through 14D show the range of the piston rod used in the autoinjector of the embodiment. Figure 15 shows an alternative configuration of the safety cap according to the embodiment. Figure 16 shows an alternative configuration of the main casing according to the embodiment. Figure 17 shows an alternative configuration of the operating unit and the power unit for use in the embodiment. Figures 18A and 18B show an alternative configuration of the cartridge sleeve for use in the embodiment. Figures 19A through D show the labeling arrangement used in the embodiment.

Best Mode for Carrying Out the Invention

[0062] In this specification, it should be noted that the terms "front" and "rear" are used for the convenience of referring to the sides of the device with reference to the orientation during typical use. Thus, the front generally may mean the surface, component, or direction that is close to or faces the drug delivery end (e.g., the needle end) of the device. Similarly, the rear generally may be understood to mean the surface, component, or direction that is distal from the delivery end. However, such references are not intended to be limiting, and it will be understood that the device may be in any orientation during use. References to circumferential, radial, or axial directions may also be used herein as generally geometric terms for the orientation with respect to the longitudinal axis of the auto-injector device (which typically coincides with the longitudinal direction towards the needle end). However, such terms are not intended to be construed narrowly or restrictively and do not exclude, for example, the possibility that a component may have a non-circular or irregular shape.

[0063] An auto-injector 1 according to an embodiment of the present invention is shown in FIGS. 1 to 5. The auto-injector 1 includes a main casing 10 closed by a cap 20 (also referred to herein as a safety cap). Inside the main casing 10, a cartridge assembly 30, an actuation unit 50, and a power pack 100 including a spring 130 are provided. The actuation unit 50 includes a cartridge container 52, a needle cover 60, and a needle cover spring 70. The needle cover 60 is disposed between the cartridge container 52 and the main casing 10 in the radial direction.

[0064] The auto-injector 1 includes a main casing 10 that can be formed from two body shells 11 and 12, which are configured to snap-fit elastically during the assembly of the device. The snap connection is typically an irreversible engagement such that the end user cannot disassemble the casing 10 and thus cannot access the internal components of the auto-injector 1. A label (described later) locks the two body shells 11, 12 together by bridging the joint therebetween, enhancing the strength and making it more difficult to disassemble the body shells 11, 12. Thus, advantageously, the auto-injector can be supplied without the need for a protective case or a carrying case. The main casing 10 has an elongated tubular shape with a closed rear end and an opening 14 at the front end. With the rear end closed, the user can immediately identify from which end of the device it is to be operated, enabling intuitive use of the auto-injector. The cross-sectional shape of the casing 10 is generally oval. The oval is widely used herein and is understood to include an elliptical or super-elliptical cross-section and may enable the attachment of a label to the main casing. The oval advantageously rolls and thus prevents accidental drops from the surface.

[0065] The main casing 10 may be formed from an injection-molded plastic material. The main casing may be opaque. One or more windows 15 may be formed on the side surface of the casing 10, for example, in the form of through openings. To close the window openings, a transparent window piece 16 can be inserted into the main casing 10. In the illustrated embodiment, the window piece is annular and includes two half parts 16a, 16b, each of which interconnects with the respective body shells 11, 12 of the main casing 10. The window pieces each further include locking arms 17a, 17b that project forward, which will be described in more detail later. A safety cap 20 (details will be described later) is removably attached to the front end of the main casing 10 and closes the front opening 14.

[0066] As will be described below with reference to the corresponding features, the inner surface of the main casing 10 can be provided with integrally formed features that project inside the auto-injector 1 to provide a cooperating structure for the components of the operating unit 50 or the power pack 100. This feature portion includes, for example, ribs 17, flanges 18 and / or stops 13.

[0067] The cartridge assembly 30 is disposed within the main casing 10. The cartridge assembly supports a cartridge 31. The cartridge 31 is typically a glass container of a drug having a stopper 35 (not shown in FIG. 1) movable at the rear end for discharging the drug from the cartridge. The size of the cartridge 31 can be selected based on the dosage or drug to be delivered by the auto-injector, and can be in the range of 0.3 mL to 2.5 mL, for example, about 1 mL, or 1.5 mL. As will be further described below with reference to FIG. 14, in some embodiments, a single size of cartridge 31 can be used in multiple auto-injector configurations that deliver different volumes of the same drug, thus providing options for delivering different single-dose amounts in use (when the delivery volume is less, the volume of the drug remaining in the cartridge after use is greater). The front end of the cartridge 31 can be closed with an aluminum crimp cap 32 having a septum 32a (see FIG. 13), such as a bromobutyl septum, thereby sealing the drug within the cartridge. The septum 32a is pierceable and can be penetrated by the injection needle.

[0068] In front of the cartridge 31, the cartridge assembly 30 includes a needle 40 carried by a needle guide 42. A detailed cross-section showing the needle 40 is shown in FIG. 13. The rear end of the needle 40 projects beyond the needle guide 42 towards the partition wall 32a of the cartridge 31. The needle guide 42 is aligned with the front end of the cartridge 31 by a guide sleeve 44 sized to fit into the shoulder of the crimp camp 32 of the cartridge 31. A sealing ring 46 is disposed between the guide sleeve 44 and the cartridge 31 (and can pass through the crimp camp 32 during the assembly of the auto-injector so as to be mounted on the neck portion of the cartridge 31).

[0069] The cartridge assembly 30 also includes a cartridge sleeve 38 that slides around the cartridge 31 during assembly. At the rear end of the cartridge sleeve 38, a lip 39 is provided that seats on the rear (open) end of the cartridge 31. The lip 39 defines an opening at the rear of the cartridge assembly that is smaller in diameter than the inner diameter of the cartridge 31. The cartridge sleeve 38 also has a window 37 in the form of a through-opening so as not to obstruct the view of the contents of the cartridge 31. The cartridge sleeve 38 is axially and rotationally connected to the piston rod 140 such that rotation does not cause the window to become invisible. The piston rod 140 can move forward but not backward.

[0070] The power pack 100 is also disposed within the main casing 10 to move the cartridge assembly 30 relative to the main casing 10 from a storage position to an injection position during operation (as described below). The power pack 100 includes an inner body 110, an outer body 120, a spring 130, and a piston rod 140. The spring 130 stores energy for actuating the auto-injector 1 and, when released, is used to drive the piston rod 140 and the cartridge assembly 30 to an 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 actuate the device. The assembled power pack 100 is shown separated and in various stages of operation in FIGS. 6 through 8.

[0071] The piston rod 140 is a one-piece component. The piston rod 140 extends through the rearward opening of the cartridge 31 and has a forward portion 141 configured to engage the piston 35. The engaging end of the forward portion 141 can have an enlarged or bulbous head 142 for engaging the piston 35. The lip 39 of the cartridge sleeve 38 has an opening with an inner diameter smaller than the outer diameter of the head 142 of the piston rod. As such, the lip 39 engages the rearward end of the head 142 to maintain 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 (the spring 130 and the piston rod 140 are generally coaxial). A 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 to which the forward end of the spring 130 is attached. 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 (further described below).

[0072] The inner body 110 is a substantially tubular one-piece component that generally surrounds the piston rod 140 and the spring 130 (the spring is radially intermediate the rod and the inner body). The front end of the inner body 110 includes latch members 116a, 116b that provide a snap-together assembly function between the power pack 100 and the actuating unit 50. The rear end of the inner body 110 comprises a collet 112. The collet 112 includes four collet arms 113 that are circumferentially distributed around the inner body 110 and each of which is a segment of the collet 112. Each collet arm 113 extends rearwardly from a collar 114. The collar 114 has an elliptical cross-section that generally conforms to the shape of the autoinjector 1 defined by the main casing 10 (and supports and aligns the outer body 120 relative to the inner body 110). The collar 114 includes a recess 115 configured to receive and hold the head 126 of a latch arm 125 (described further below) of the outer body 120.

[0073] As best seen in FIGS. 2 and 6, the collet 112 of the inner body 110 is formed and configured to engage and hold the latch head 148 of the piston rod 140. Specifically, the rear end of each collet arm 113 includes an engagement surface that extends radially inward, which engages with the front shoulder of the latch head 148 in the initial state of the device. It should be noted from the cross-sectional view of FIG. 6 that the shoulder of the latch head 148 and the engagement surface of the collet arm 113 are provided with cooperating inclined surfaces 148a and 113a, respectively. Specifically, the inclined shapes of the cooperating surfaces 148a and 113a are inclined forward and inward so that the latch head 148 can slide forward while cam-moving the collet arm 113 outward through the collet 112 (as further described below). The rear end of the collet arm 113 further defines an annular forward-facing surface below the collet 112. The forward-facing surface provides a spring shoulder to which the rear end of the spring 130 is attached. In the illustrated embodiment, there are four collet arms 113, two of which support the piston rod 140 and release the piston rod when the collet is moved, and the other two collet arms 113 provide a spring shoulder for the spring 130.

[0074] The outer body 120 is generally an elliptical tubular body that circumferentially surrounds the inner body 110 (as if it is in the middle between the inner body and the main casing). The outer body 120 can be considered as a trigger member that maintains the engagement between the collet 112 and the piston rod 140 in the initial position against the biasing force of the spring 130. As will be described below, the relative axial movement between the inner body 110 and the outer body 120 can move the outer body 120 out of alignment with the collet arm 113, enabling the collet to disengage. Since the outer body 120 is generally fixed relative to the main casing 10, the outer body 110 and the main casing 10 have an interconnected shape to provide a secure position therebetween. For example, in the illustrated embodiment, the main casing 10 includes an inner flange 18 against which the front end of the outer body 120 abuts when the auto-injector is assembled.

[0075] The front 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, and the tabs of each pair are circumferentially spaced apart. As will be described below, the tabs 122 provide an interaction surface for the needle cover 60, enhance the robustness of the auto-injector, and ensure the correct sequence of spring release. The tabs 122 further function as a push rod for releasing the needle cover 60 in that when the needle cover lock latch 64 (also referred to herein as a hook) is pressed, the arm 63 of the lock latch bends to release the grip on the tower 56 (also referred to herein as a boss) on the cartridge container 56.

[0076] The outer body 120 also includes two latch arms 125 that extend rearwardly. The latch arms 125 are diametrically opposed. Each latch arm 125 is a flexible axially elongated member integrally formed with the outer body 120. The latch arms extend from a front end continuous with the outer body 120 to a free rear end that includes a head 126 that projects inwardly.

[0077] The autoinjector 1 further comprises an operating unit 50 including a cartridge container 52, a needle cover 60 and a needle cover spring 70. FIGS. 10 to 12 show exploded views of the operating unit 50 and the power pack 100 at various stages of operation. The cartridge container 52 is a generally tubular body configured to surround the cartridge 31 and the cartridge assembly 30 (including the needle assembly 40). The front end of the cartridge container 52 includes an opening 53 initially closed by a membrane 54. The cartridge assembly 30 is inserted into the cartridge container 52 from the rearward end opening. As best seen in the details of FIG. 13, the sealing ring 46 of the cartridge assembly 30 can provide a seal between the outer surface of the cartridge 31 and the inner surface of the cartridge container 52. By being disposed around the neck portion of the cartridge 31, the sealing ring 46 provides a compact arrangement and also ensures correct (coaxial) positioning of the front end of the cartridge (assisted by the guide sleeve 44) within the cartridge container 52.

[0078] The front portion of the cartridge container 52 can form an axially extending chamber (S in FIG. 13) from the membrane 54 to the sealing ring 46. Prior to operation of the autoinjector 1, the needle assembly is fully accommodated within the chamber S to maintain the sterility of the needle assembly 40. The chamber S may have a gas-permeable opening, for example, one or more of the membrane 54, the sealing ring 46 or a dedicated orifice may include a gas-permeable material. In a chamber S sealed by a porous material, bacteria, viruses, fungi cannot penetrate around the needle assembly 40. However, this material does not act as a barrier to gases (including gases in the atmosphere). This configuration allows the assembly to be sterilized during manufacture using a gas such as ethylene oxide. In the illustrated embodiment, a gas-permeable membrane 54 is used, but in other embodiments, alternative methods of maintaining a sterile barrier within the cartridge container 52 can be provided.

[0079] At the rearmost part of the cartridge container 52, an interface is provided that enables the interconnection between the operating unit 50 and the power pack 100. This interconnection is best shown in FIGS. 10 to 12. In particular, the cartridge container 52 is provided with a pair of slots 55a, 55b configured to receive the latch members 116a, 116b of the inner body 110 of the power pack 100. The slots 55a, 55b include a front end having a shoulder over which the latch member 116 can snap to couple the power pack 100 and the operating unit 50. When the latch member 116 snaps into a predetermined position in the slot 55, the needle cover spring 70 is axially between the inside of the latch on the inner body 110 and the cartridge container 52 (see, for example, FIGS. 10 to 12). Note that in this way, the needle cover spring 70 is under the end of the latch member 116. This arrangement advantageously supports the latched configuration of the latch 116 and the slot 55 and prevents the latch member 116 from disengaging and flexing when the auto-injector 1 is assembled (thus enhancing the robustness of the assembled connection between the power pack 100 and the operating unit 50).

[0080] The rear end of the cartridge container 52 also includes a radially outwardly projecting boss 56. Two pairs of bosses 56 are arranged on opposite side faces of the cartridge container 52, and each pair of bosses is circumferentially spaced apart. As will be described below, the bosses provide a fastener for the connection between the cartridge container 52 and the needle cover 60. Adjacent to the boss 56, a forward-facing seat 58 for receiving the rear end of the needle cover spring 70 is also provided.

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

[0082] The needle cover 60 is also a substantially tubular member that surrounds the cartridge container 52 from the outside such that the needle cover is disposed between the cartridge container 52 and the main casing 10. The needle cover includes a front portion 61 that closely conforms to the outer shape of the cartridge container 52 with a slight clearance, and a rear portion 62 with an increased cross-sectional area. The shape of the rear portion 62 provides an annular cavity around the cartridge container 52, which houses the needle cover spring 70 and allows the spring to be accommodated between the cartridge container 52 and the needle cover 60. The interface between the rear portion 62 and the front portion 61 of the needle cover 60 can include a step change in shape such that a rearward-facing seat 65 for the front end of the needle cover spring 70 is defined.

[0083] The needle cover 60, which is integrally formed with the rear portion 62, includes four hooks 64 respectively formed at the ends of four resilient rearwardly extending arms 63. As will be further described below, the hooks 64 form a first locking assembly that engages with the bosses 56 of the cartridge container 52 in the initial configuration and forms a fastener between the needle cover 60 and the cartridge container 52. The fastener holds the needle cover in a first position against the forward biasing of the needle cover spring 70. The needle cover spring 70 is initially compressed between a rearward-facing seat 65 of the needle cover 60 and a forward-facing seat 58 of the cartridge container 52. It should be noted that the rear end of the needle cover spring is also supported by a stop 13 that projects inwardly of the main casing 10 (particularly in the cross-sectional views of FIGS. 2A and 3B). In the initial (pre-use) configuration of the auto-injector 1, the stop 13 and the forward-facing seat 58 are longitudinally aligned.

[0084] The needle cover 60 also includes a second locking assembly having a pair of elastic members 67a and 67b that extend outwardly in diametrically opposed directions. Each elastic member 67 is integrally formed with a rear portion of the front portion 61 of the needle cover 60. The elastic member projects outwardly and rearwardly from a front end integral with the needle cover 61 to a free end 68. As will be further described below, since the elastic member 67 is angled rearwardly, it cams inwardly during forward movement and can elastically flex inwardly past a feature such as a ledge with its free end 68. In contrast, during rearward movement, the free end 68 of the elastic member engages a feature such as a ledge to lock the needle cover 60.

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

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

[0087] The cap 20 has an oval cross-section and has a cup-shaped shape with a closed front end 21 and an open rear end 22. On the outside of the cap 20, one or more tactile features can be provided so that the user can easily and intuitively grip it. Advantageously, in the illustrated embodiment, the tactile feature is three ridge-shaped ridges, which provide additional grip (gip) and indicate the direction and movement required to remove the safety cap 20. The oval cross-section of the safety cap has a shape complementary to the tapered front end of the main casing 10. The cap 20 and the main casing 10 are configured to provide a sliding fit that allows for attachment and re-capping of the front ends of the cap 10 and the main casing 10 to cover the front opening 14. As best shown in FIGS. 2B, 3A, and 3B, a detent is provided for releasably attaching the safety cap 20 to the front end of the main housing 10. For example, on the inner surface of the cap 20, there are provided protrusions 23 that engage corresponding features 19 (shown in FIG. 2B) provided on the outer surface of the main casing 10.

[0088] Internally, the cap 20 is configured to cooperate with the outer peripheral surfaces of the lock arms 17a, 17b of the main casing 10. In particular, the cap 20 can include inwardly projecting features such as ribs 25a, 25b, which press the lock arms 17a, 17b radially inward relative to the actuating unit 50 such that the ends of the arms extend through the through openings 66a, 66b of the needle cover 60 and engage the respective recesses 57a, 57b of the cartridge container 52. In this way, when the cap 20 is in a predetermined position (e.g., attached) on the outer casing 10, the actuating unit 50 is locked in a predetermined position relative to the outer casing 10.

[0089] Next, the operation of the auto-injector 1 will be described. The initial configuration of the auto-injector pen (for example, the configuration before use as distributed to the end-user) is shown in FIG. 2 with the safety cap 20 attached to the front end of the outer casing 10. The corresponding configuration of the power pack 100 is shown in FIG. 6, and the actuation unit 50 and the power pack 100 are shown in FIG. 10. In this configuration, the rib 25 of the cap 20 presses the locking arm 17 inward to lock the actuation unit 50 to the casing 10. The needle cover 60 is latched to the power unit 100 by the engagement of a first locking mechanism (the hook 64 engages with the boss 56 of the cartridge container 52). In this position, the needle cover spring 70 has its front end on the rearward-facing seat 65 of the needle cover 60 and its rear end abuts against both the seat 58 of the cartridge container and the stop 13 of the main casing 10 and is held in a compressed state.

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

[0091] Note that the power pack 100 can also be provided with a safety pin 150 (shown in FIG. 6) that mechanically prevents movement between the inner body 110 and the outer body 120. The safety pin 150 can be inserted through a suitable through-opening in the main casing 10 (see 151 in FIG. 19A for example). Such a safety pin can be used, for example, to prevent the power pack from being accidentally released during the assembly of the auto-injector 1. When the auto-injector 1 is fully assembled (when the cap 20 is attached), the safety pin 150 is no longer necessary to isolate the power pack. Therefore, the safety pin can be removed in one of the final assembly steps, before the auto-injector is packaged and shipped to the end user. The label 200 (described later) passes through the hole where the safety pin 150 extended, providing ingress protection and structural robustness.

[0092] In the initial configuration, the window 15 of the outer casing 10, the window 69 of the needle cover 60, and the window 37 of the cartridge sleeve 38 are aligned while the cartridge container 52 is made of at least partially transparent material. Therefore, the user can visually inspect the drug in the cartridge 31 through the aligned windows 15, 69, 37 and the aligned transparent regions of the cartridge container 52 without being obstructed from the view.

[0093] When it is necessary to use the auto-injector 1, the user removes the cap 20 by axially pulling it away from the main casing 10. The detents 19, 23 of the main casing 19 and the cap 20 provide a slight resistance, which the user can easily overcome. The operable state of the device is shown in FIG. 3, and the state of the corresponding power pack is shown in FIG. 7. Note that with the cap 20 removed, the front end of the actuating unit 50 (including the front portions of both the needle cover 60 and the cartridge container 52) extends in front of the opening 14 of the main casing 10. In this initial state, note that the needle assembly 40 is arranged such that the rear needle tip is in front of the partition 32a and the front needle tip is behind the membrane so as to completely enter the sterile chamber defined within the cartridge container 52.

[0094] When the cap 20 is removed, the locking arms 17a, 17b are no longer held inwardly and elastically spread outwardly, and the ends can disengage from the engagement with the recesses 57a, 57b of the cartridge container 52. This releases the cartridge container, which can move rearward to release the spring.

[0095] If the user chooses not to operate the auto-injector 1, the removal of the safety cap 20 from the casing 10 can be reversed by repositioning the safety cap 20 onto the auto-injector. Such re-capping of the auto-injector 1 causes the ribs 25a, 25b to engage the locking arms 17a, 17b again and engage the recesses 57a, 57b. Thus, re-capping places the auto-injector in a safe state and locks the actuating unit 50 in a predetermined position relative to the outer casing 10. The re-capping function of the safety cap 20 is optional. Further, since the needle assembly 40 does not move away from the sterile chamber S during removal or replacement of the cap 20, the sterility of the device is maintained even if the user removes the cap of the device without subsequent actuation.

[0096] To operate the auto-injector 1, the user grasps the main casing 10 and presses the front end of the device (the front end of the actuating unit 50, e.g., the front end of the cartridge container / needle cover) against the injection site. Due to the force applied to the front end, the actuating unit 50 moves rearward relative to the main casing 10. The locking arms 17a, 17b of the main casing 10 are no longer constrained inwardly and can flex outwardly, thus not preventing relative movement. The cartridge container 52, the needle cover 60, and the needle cover spring 70 of the actuating unit all move rearward.

[0097] During the first rearward movement of the actuating unit 50, the seat 58 of the cartridge container is moved rearward away from the stop 13 on the main casing 10. The seat 65 of the front portion of the needle cover 60 moves longitudinally towards the stop 13. The rear end of the needle cover spring 70 cannot move beyond the stop 13 and disengages from the seat 58. Thus, due to the movement of the actuating unit 50, the needle cover spring 70 is further compressed between the seat 65 and the stop 13. Advantageously, this configuration helps to provide a reliable actuating force for the auto-injector (e.g., 40 - 60% of the force may be provided by the spring).

[0098] Furthermore, the compression of the needle cover spring 70 can be used to ensure that the auto-injector returns to a safe pre-use position when not in operation (thus enabling safe recap). Specifically, if the user performs only a partial actuation operation before removing the pressure on the device (i.e., does not fully press the auto-injector 1 to move the actuating unit 50 to the actuating position where drug delivery starts), the needle cover spring 70 acts to return the actuating unit 50 to its pre-use or storage configuration by biasing the actuating unit 50 forward relative to the main casing 10 until the stop 13 and the seat 58 are readjusted.

[0099] By connecting the inner body 110 of the power unit 100 to the cartridge container 52, the inner body of the power unit 100 also moves relatively rearward together with the operating unit 50. The inner body 110 moves integrally with the piston rod 140 and the spring 130. The outer body 120 of the power unit 100 is fixed relative to the main casing 10. As a result, due to the relative movement between the outer body 120 and the inner body 110, the collet 112 of the inner body 110 moves rearward out of alignment with the peripheral portion of the outer body 120. This can be clearly seen in the separated views of FIGS. 8 and 11, although the inner body 110 extends rearward beyond the outer body 120.

[0100] As a result of the rearward movement, the radial outward expansion of the collet 112 is no longer restricted. 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 inclination of the cooperating surfaces 148a, 113a cams the collet arm 113 radially outward, releasing the latch head 148 of the piston rod 140. Thereby, the spring 130 can act freely and start pushing the piston rod 140 forward. It can be noted that in connection with this release of the piston rod 140, the head 126 of the latch arm 125 of the outer body 120 moves out of the recess 115 of the collar 114 of the inner body. This enables the latch arm 125 to snap inward in front of the collar 114. Thus, the trigger configuration of the power unit 100 is maintained even if the user does not continue to maintain pressure on the main casing 10 of the auto-injector 1.

[0101] During operation, 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 in to engage with the tab 122 of the outer body 120. As a result, the elastic arm 63 carrying the hook 64 elastically deflects laterally so as to disengage from the engagement with the boss 56. As a result, the lock of the needle cover 60 is released, and it is ready to deploy under the forward force of the needle cover spring 70. However, at this stage, since the front end of the auto-injector 1 is still in contact with and held at the injection site, the needle cover 60 does not normally deploy.

[0102] As shown in FIG. 4, after the release of the piston rod 140, the spring 130 pushes the cartridge assembly 30 forward. Initially, this causes the forward end of the needle to be pushed out through the porous filter membrane 54. When the needle guide 42 reaches the inner front surface at the forward end of the cartridge container 52, the rearward end of the needle passes through the partition wall 32a of the cartridge 30 and establishes a fluid path after the needle is fully extended. When the needle assembly 40 and the cartridge 31 reach the front of the cartridge container 52, they can no longer move, and the force of the spring 130 causes the piston rod 140 to move the stopper 35 forward within the cartridge 31 and administer the dose through the needle 40. When the full dose is administered, the flange 145 of the piston rod 140 reaches the lip 39 of the cartridge sleeve 38 and prevents further forward movement. Thus, it will be understood that the position of the flange 145 on the piston rod 140 provides a convenient feature that can be changed to provide an auto-injector capable of delivering different volumes, and thus different doses, of the drug.

[0103] As shown in FIGS. 5 and 12, when the injection is completed, the user can remove the auto-injector 1 from the injection site. Since the needle cover 60 was unlocked during operation and throughout the injection phase, the needle cover spring 70 acts on the needle cover 60 and can deploy the needle cover from the front end of the main casing 10, unless the front end of the auto-injector is held and manually forced not to deploy. When the needle cover 60 is fully deployed (when the front end of the cover extends far enough to exceed the front most tip of the needle), the second lock assembly acts to lock the cover. The second lock assembly acts automatically as a result of an outwardly extending resilient member 67 of the needle cover 60 passing through an inwardly extending rib 17 formed in the main casing 10. The angled arrangement of the resilient member 67 allows the resilient member 67 to freely cam over the rib 17 during forward movement of the cover 60 (under the pressing force of the cover spring 70). Beyond the rib 17, the resilient member 67 springs back to an outward position. Thus, the needle cover 60 is locked against rearward movement as the resilient member does not pass through the rib 17 in the reverse direction.

[0104] In this configuration, since the needle 40 is completely covered by the cover 60, the auto-injector 1 cannot be activated again, which is safe. The user can visually confirm that the auto-injector is no longer operating based on the position of the needle cover and because the window 15 of the main casing 10 is blocked by a part of the needle cover. Since the needle cover 60 extends forward, the user cannot replace the cap 20 on the main casing 10 (because the detents 19, 23 of the main casing 19 and the cap 20 cannot be aligned). Also, note that the cross-sectional shape of the needle cover 60 is circular, while both the cap 20 and the main casing 10 are elliptical. This serves as an effective visual indication to deter users from attempting to recap (reuse) the used device. Furthermore, the shapes of the cap 20 and the main casing 10 can be selected such that, even if a recap attempt is made (before activation), the cap does not apply pressure to the needle cover (because it only engages with the large elliptical shape of the main casing). After use, the needle cover 60 extends far beyond the main casing 10, making it impossible to recap.

[0105] Figures 14A - 14D illustrate how the auto - injector of the embodiment can be adapted to provide various dosing amounts by selecting an appropriate piston rod 140, without the need to change other aspects of the device. The piston rod 140 in Figure 14A is as shown in the embodiments of Figures 1 - 12, and includes a single flange 145' at an axial central position that defines a separation between a forward portion 141 and a rearward portion 146 of the piston rod. The rear face of the flange 145a provides a spring shoulder to which the forward end of the spring 130 is attached. The front face 145b of the flange 145 defines a stop surface that abuts against 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. In Figure 14B, 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 flange members 145' - however, it will be understood that a stiff flange with an increased axial thickness could have the same function. The rearward face 145a' can be positioned at the same axial position as in the embodiment of Figure 14A so that the action of the spring 130 is not altered by the use of the modified piston rod 140'. In contrast, by positioning the forward face 145b' axially forward, the range in which the piston rod 140 can enter the cartridge 31 before being stopped by the engagement between the face 145a' and the lip 39 is reliably reduced. Thereby, the dosing amount provided by the operation of the auto - injector is reduced. Further variations are shown in Figures 14C and 14D, which are substantially identical to the embodiment of Figure 14B, but with the axial spacings "y" and "z" between the respective rear faces 145a'', 145a'' and the respective front faces 145b'', 145b'' increased. The larger the axial spacing, the smaller the dosing amount delivered during operation of the device. - This enables the manufacture of various devices that deliver different dosing amounts using the same major components with only the piston rod changed (e.g., it becomes possible to manufacture all injectors on a single production line).

[0106] As shown in FIGS. 19A-19D, it should be noted that the auto-injector 1 is typically provided to the end user with a label 200 wound (adhered) around the outer surface of the main casing 10. In the initial assembly configuration shown in FIG. 19A, the auto-injector 1 does not have a label. In this arrangement, note that there are a number of openings in the main casing 10. For example, the opening 151 at the rear end of the casing 10 can include at least one opening provided for a safety pin 150 that prevents the operation of the power pack during manufacture. Additional openings 155 may be provided at the front end of the casing 10, for example, to assist the flow of gas into the needle compartment S during sterilization of the auto-injector. The label 200 can be formed as a single web, as shown in FIG. 19C. The label has opposing side surfaces 205, 206, straight end portions 208, and a front end 210 shaped to conform to the shape and configuration of the front end of the auto-injector casing 10. A pair of cuts 201, 202 are included and are of a shape and size that match the window 15 of the casing 10. As seen in FIG. 19D, the label can be wound such that the side surfaces 205 and 206 are adjacent and form an axially extending tube. In the wound state, the cuts 201, 202 are diametrically opposed. As shown in FIG. 19B, as a final step in the assembly of the auto-injector 1, the label 200 is wound around the casing 10 (it may be self-adhesive, for example, to adhere the label to the surface of the casing). By the label 200 being in place, the openings 151, 155 of the casing 10 are covered, and as a result, the label 200 can provide intrusion protection for the auto-injector 1. Since the main casing 10 is formed of two parts, the label 200 can also be arranged to cover the joint between the casing parts (thereby, for example, providing protection against tampering and enhanced robustness).

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

[0108] For example, it will be understood that the locking arrangement between the actuating unit 50 and the cap 20 can be formed in various ways. One alternative configuration is shown in the embodiment of FIG. 15. In this arrangement, the cap 1520 is formed with a rearwardly projecting rib 1525 that presses or holds the locking arm 1517 outwardly so as to engage with the main casing 1510. When the locking arms 1517 are supported inwardly by the rib 1525, they cannot be compressed inwardly to overcome the inwardly projecting shoulder (or other such feature) of the housing. Thus, the cap 1520 prevents relative movement between the housing 1510 and the actuating unit 1550.

[0109] Another embodiment is shown in FIG. 16, in which the locking arm 1617 is integrally formed as part of the main casing 1610. The locking arm 1617 can be formed as a forwardly extending tongue separated from an adjacent portion of the housing by axially extending slots 1617a and 1617b such that the forward end is elastically deflectable. The cap of this embodiment can act on this forwardly extending tongue, similar to the locking arm 17 of the embodiments of FIGS. 1 to 14.

[0110] FIG. 17 shows an alternative arrangement of a first locking assembly for holding the needle cover in its first (retracted and retracted) position. In this embodiment, the hooks 1764 are directed radially outward and are provided on a pair of arms 1763 formed proximate the centerline of the rear portion of the needle cover 1760. Usually, the same configuration is provided on the opposite side of the auto-injector. The hook 1764 engages a boss 1756 to lock the needle cover 1760 in place. Note that the boss 1756 in this embodiment is formed in the inner body 17110 rather than in the cartridge container 1752 (since the cartridge container 1752 and the inner body 17110 are fixed relative to each other, either component may include the boss).

[0111] The outer body 17120 of the power unit 17100 includes a cooperating cam surface 17122 that faces an angled surface 1764a formed on the hook 1764. During use, it will be appreciated that the angled surface 1764a is engaged by the cam surface 17122 due to relative movement between the needle cover 1760 and the outer body 17120 (i.e., during operation of the auto-injector). The cam surface 17122 compresses the arms 1763 together, releasing the hook 1764 from engagement with the boss 1756 and freeing the needle cover 1760 for forward movement.

[0112] Figures 18A and 18B show an alternative cartridge sleeve 1838 that may be used in an embodiment. Figure 18A shows the configuration during use of the cartridge sleeve 1838 (i.e., when assembled within the auto-injector), and Figure 18B shows the configuration prior to assembly. In contrast to the embodiments of Figures 1 to 14 where one side is open (except for the lip 39) to allow insertion of the cartridge 31, the cartridge sleeve 1838 is formed from two axially extending leg portions 1838a and 1838b that are connected at the front end by an annular portion 1838c. The sides of the legs 1838a and 1838b are formed to define a window 1837 therebetween when disposed around the cartridge. The lip 1839 is formed by respective portions 1839a and 1839b at the rear end of the cartridge sleeve 1838 and seats on the rear portion of the cartridge similar to the lip 39 of the previous embodiments. The cartridge sleeve may have an initial configuration in which the legs 1838a and 1838b are spread apart to facilitate insertion of the cartridge 31, as shown in Figure 18B, and during use, the legs may elastically flex together to close around the cartridge (and be held in place by the surrounding cartridge holder 52). Alternatively, the stationary configuration of the sleeve 1838 may be as shown in Figure 18A, and the legs 1838a and 1838b may elastically spread apart to insert the cartridge 31 before springing back to the closed configuration.

[0113] Embodiments of the present invention may include features according to the following numbered listings (which are not the subject matter recited in the claims as defined in the appended claims for the purpose of avoiding misunderstanding): 1. A main casing, and A cartridge assembly disposed within the main casing and having a cartridge containing a drug and a needle, and A power pack disposed within the main casing and, when actuated, moves the cartridge and needle from a storage position to an injection position relative to the main casing, and An operating unit comprising a cartridge container and a needle cover disposed between the cartridge container and the main casing, wherein the operating unit is operatively coupled to the power pack and is retractable relative to the main casing from a first position to an operating position for actuating the power pack, and thereafter the needle cover is extendable to an extended position covering the needle when the cartridge and needle are in the injection position, and A safety cap removable from an attachment position at the front end of the main casing for exposing the front portion of the operating unit, the safety cap being arranged to press a locking arm against the operating unit to lock the operating unit against retraction from the first position until the safety cap is removed, and An auto-injector comprising. 2. The auto-injector according to statement 1, wherein the safety cap includes a rib or other inwardly projecting structure for pressing the locking arm against the operating unit to lock the operating unit against retraction from the first position until the safety cap is removed. 3. The auto-injector according to statement 1, wherein the operating unit and the locking arm of the main casing are lockably engaged when the safety cap is in the attachment position and are free or biased to disengage from the lock when the safety cap is removed. 4. The actuating unit includes a recess or a stepped structure on its outer surface, and the locking arm is pressed by the safety cap to engage with the recess or the stepped structure when the safety cap is in the attached position. The auto-injector according to statement 1. 5. When the safety cap is removed, the locking arm is in a free state or a biased state so as to disengage from the engagement with the recess or the stepped structure and spread outward. The auto-injector according to statement 4. 6. The front portion of the actuating unit has a circular cross-section, and the safety cap has an elliptical cross-section. The auto-injector according to statement 1. 7. The safety cap and the main casing include a mechanically cooperating mechanism having a detent for releasably attaching the safety cap to the front end of the main housing. The auto-injector according to statement 1. 8. The front ends of the safety cap and the main casing have cooperating elliptical cross-sections to provide a sliding fit attachment and re-capping of the front end of the safety cap and the main casing. The auto-injector according to statement 1. 9. The safety cap is removable from the front end of the main casing by translation without rotation. The auto-injector according to statement 1. 10. The needle cover includes a through-opening, the cartridge container includes a recess, and the front end portion of the locking arm extends through the opening and is pressed to engage with the recess of the cartridge container. The auto-injector according to statement 1. 11. Comprising first and second locking arms arranged at diametrically opposed positions, the safety cap is arranged to press the first and second locking arms against the actuating unit when the safety cap is in the attached position, locking the actuating unit against retraction from the first position until the safety cap is removed. The auto-injector according to statement 1. 12. The auto-injector according to statement 1, wherein the locking arm has a front end enlarged so as to protrude inwardly. 13. A main casing, a cartridge assembly disposed within the main casing and including a cartridge containing a drug and a needle, a power pack disposed within the main casing for moving the cartridge and the needle from a storage position to an injection position relative to the main casing during operation, wherein the power pack includes an inner body, an outer body, a spring, and a piston rod, the inner body having at least one collet arm movable between a retracted position and a position expanded outwardly, the inner body being disposed within the outer body and movable therein between a non-operating position and a release position, the outer body engaging and holding at least one collet arm of the inner body with the piston rod when the inner body is in the non-operating position to maintain the storage position of the piston rod against the biasing of the spring, and when the inner body is in the release position, the at least one collet arm freely moves to a position where it expands, thereby releasing the piston rod to move the cartridge assembly by the action of the spring, and a needle cover operatively coupled to the power pack and being retractable from a first position to an operating position relative to the main casing to operate the power pack by moving the inner body of the power pack from the non-operating position to the release position, and then being extendable to an extended position covering the needle when the cartridge and the needle are in the injection position, An auto-injector comprising the above. 14. The auto-injector according to statement 13, wherein the spring is disposed between the piston rod and the inner housing. 15. The auto-injector according to statement 13, wherein the needle cover includes at least one hook engaging a fastener included in the auto-injector to hold the needle cover in the first position. 16. The latch is disposed on the cartridge container, and the automatic injector according to statement 15, wherein the needle cover is disposed between the main casing and the cartridge container. 17. The automatic injector according to statement 16, wherein at least one hook is deflected by the outer body when the needle cover is retracted from the first position to the actuated position, whereby at least one hook is released from the latch. 18. The automatic injector according to statement 13, wherein when at least one collet arm is in the retracted position and the inner body is in the non-operated position, at least one collet arm of the inner body and the rear end of the piston rod include mating tapered surfaces. 19. The automatic injector according to statement 13, wherein the piston rod is a one-piece molded part. 20. The automatic injector according to statement 13, wherein a spring is coiled around the piston rod and has opposing ends respectively positioned against a spring shoulder of the piston rod and under a collet of the inner body, and the collet comprises at least one collet arm. 21. The automatic injector according to statement 13, wherein the inner body is movable rearwardly within the outer body between a non-operated position and a release position, and the inner body, the piston rod and the spring move as a unit. 22. The automatic injector according to description 13, wherein the inner body comprises a collet, and at least one collet arm comprises at least three collet arms constituting the collet. 23. The main casing, a cartridge container housed in the main casing, a cartridge assembly disposed within the cartridge container and including a cartridge and a needle, the cartridge including a drug and a stopper movable within the cartridge for dispensing the drug through the needle, A power pack disposed within the main casing, the power pack including a piston rod for moving a cartridge and a needle from a storage position to an injection position relative to the main casing during operation. A neck portion of the cartridge, the neck portion including a sealing ring disposed between the cartridge and the cartridge container. An auto-injector comprising the above. 24. The auto-injector according to statement 23, wherein the cartridge includes a partition wall, the rear end of the needle is spaced from the partition wall when the cartridge is in the storage position, and the rear end of the needle penetrates the partition wall when the cartridge is in the injection position. 25. The auto-injector according to statement 23, wherein an opening at the front end of the needle cover or the cartridge container includes a membrane that is penetrated by the injection needle when the cartridge and the injection needle are in the injection position. 26. The auto-injector according to statement 25, wherein the membrane is a porous filter membrane that provides a sterilization barrier for allowing the passage of atmospheric gas and preventing the passage of bacteria. 27. The auto-injector according to statement 25, wherein the porous filter member and the sealing ring provide a sterile chamber within the cartridge container. 28. The auto-injector according to statement 23, wherein the cartridge is a glass vial. 29. A main casing, A cartridge container disposed within the housing, A cartridge assembly disposed within the cartridge container and including a cartridge containing a drug and a needle, A power pack disposed within the main casing, the power pack being operable to move the cartridge from a storage position to an injection position relative to the main casing when activated, A needle cover operably coupled to the power pack, the needle cover being retractable relative to the main casing from a first position to an operating position for activating the power pack, and then extendable to an extended position for covering the needle when the cartridge and the needle are in the injection position. comprising, a needle cover is positioned between the main casing and the cartridge container, the main casing includes a casing window, the needle cover includes a needle cover window, when the needle cover is in the first position, the casing window and the needle cover window are aligned, and when the needle cover is in the extended position, the solid body of the needle cover is visible through the casing window, an autoinjector. 30. The cartridge is wrapped in a cartridge sleeve that serves to connect the piston rod of the power pack and the cartridge assembly, the cartridge sleeve includes a cartridge sleeve window, and the autoinjector according to statement 29 in which the casing window, the needle cover window, and the cartridge sleeve window are aligned when the needle cover is in the first position. 31. The autoinjector according to statement 29, comprising a needle cover spring, the needle cover being extendable to the extended position by the action of the needle cover spring, and the needle cover spring being longitudinally disposed between the needle cover and the power pack. 32. The autoinjector according to statement 31, wherein the needle cover spring is disposed around the cartridge container. 33. The autoinjector according to statement 31, wherein the needle cover spring is positioned behind the casing window when the needle cover is in the first position and when the needle cover is in the extended position. 34. The autoinjector according to description 29, wherein the main casing is opaque and the casing window is a through-opening. 35. The autoinjector according to statement 34, wherein the casing window is filled with a transparent window piece. 36. The main casing; a cartridge container, and a cartridge disposed within the cartridge container, the cartridge containing a medicament and a cartridge assembly including a needle, A power pack disposed within the main casing, the power pack being operable to move the cartridge assembly from a storage position to an injection position relative to the main casing, A needle cover operably coupled to the power pack, the needle cover being retractable relative to the main casing from a first position to an operating position for actuating the power pack and extendable to an extended position covering the needle when the cartridge assembly is in the injection position, Comprising, The needle cover is locked against forward movement at the first position by a first locking assembly and locked against rearward movement at the extended position by a second locking assembly, The first locking assembly includes a fastening assembly between the needle cover and the cartridge container at the rear end of the cartridge container that is released when the needle cover moves to the operating position, The second locking assembly includes an elastic member of the needle cover that springs beyond a ledge of the main casing when the needle cover is moved to the extended position, An autoinjector. 37. The power pack includes an inner body, an outer body, a spring, and a piston rod. The needle cover is retractable relative to the main casing from a first position to an operating position for actuating the power pack by moving the inner body of the power pack relative to the outer body from a non-operating position to a released position. The spring is released to drive the piston rod and drive the cartridge assembly to the injection position when the inner body is in the released position. The autoinjector according to statement 36. 38. The fastening assembly of the first locking assembly is disposed at the rear end of the needle cover and includes a hook that engages a first protrusion at the rear end of the cartridge container. The autoinjector according to statement 36. 39. The hook is disposed on an elastic arm that flexes to disengage from the protruding portion when the needle cover is moved to the operating position, thereby releasing the needle cover from the cartridge container so that the needle cover can move to the extended position. The automatic syringe according to statement 38. 40. The automatic syringe according to statement 36, including a needle cover spring disposed longitudinally around the cartridge container between the needle cover and the power pack. 41. The automatic syringe according to statement 36, wherein when the needle cover is in the first position, the needle cover is provided with a needle cover window for viewing the drug in the cartridge. 42. The automatic syringe according to statement 41, comprising a needle cover spring located behind the window. 43. A main casing, A cartridge assembly disposed within the main casing and including a cartridge containing a drug and a needle, wherein a piston member is disposed within the cartridge to extrude the drug through the needle when moved forward, A power pack disposed within the main casing, the power pack for moving the cartridge assembly from a storage position to an injection position relative to the main casing during operation, A cartridge sleeve including a lip at the rear end, A cartridge container disposed within the main casing, wherein the cartridge sleeve is disposed around the neck portion of the cartridge at the front end of the cartridge sleeve, and the power pack includes a piston rod having a front end that extends through the rear opening of the cartridge to engage and move the piston member forward, the front end being included in the bulbous portion of the piston rod, and the lip engages behind the bulbous portion to connect the piston rod and the cartridge. An automatic syringe. 44. The automatic syringe according to description 43, wherein a sealing ring is compressed between the cartridge container and the neck portion of the cartridge. The automatic syringe according to statement 43, wherein the cartridge sleeve is open along a part of one side surface. 46. The automatic syringe according to statement 45, wherein the cartridge sleeve is arranged around the cartridge and includes a front collar where the front portion of the cartridge extends. 47. The automatic syringe according to statement 46, wherein the front portion of the cartridge includes a partition wall. 48. A main casing, a cartridge assembly disposed within the main casing and including a cartridge containing a drug and a needle, a power pack disposed within the main casing for moving the cartridge and the needle from a storage position to an injection position relative to the main casing during operation, a needle cover spring, an operating unit including a cartridge container and a needle cover disposed between the cartridge container and the main casing, the operating unit being operably coupled to the power pack and being retractable relative to the main casing from a first position to an operating position for operating the power pack, and thereafter, the needle cover being extendable by the action of the needle cover spring to an extended position covering the needle when the cartridge and the needle are in the injection position, comprising, The needle cover spring is compressed between a spring stop fixed to the main case and the needle cover when the operating unit is in the operating position, thereby biasing the operating unit toward the front end of the main casing. Automatic syringe. 49. The automatic syringe according to statement 48, wherein the needle cover includes a rearward spring seat for receiving the front end of the needle cover spring. 50. The automatic syringe according to statement 48, wherein the rear portion of the needle cover has an enlarged cross-sectional shape for defining a cavity between the needle cover and the cartridge container, and the needle cover spring is compressed within the cavity. 51. The automatic syringe according to statement 50, wherein the interface between the rear portion and the front portion of the needle cover includes a stepped shape for defining a rearward seat for the front end of the needle cover spring. 52. The automatic syringe according to statement 48, wherein the spring retainer comprises a fixed inward projection protruding from the inner surface of the main casing. 53. The automatic syringe according to statement 52, wherein the actuating unit further comprises a forward spring seat, and the forward spring seat supports the needle cover spring when the actuating unit is in the first position. 54. The automatic syringe according to statement 54, wherein when the spring is compressed between the spring retainer and the needle cover, the forward spring seat is located behind the spring retainer when the actuating unit is in the actuated position, so that the forward spring seat disengages from the needle cover spring. 55. The automatic syringe according to statement 53, wherein the forward spring seat is located at the rear portion of the cartridge container.

Claims

1. A main casing, a cartridge assembly disposed within the main casing and having a cartridge containing a drug and a needle, a power pack disposed within the main casing and, when actuated, adapted to move the cartridge and the needle from a storage position to an injection position relative to the main casing, an operating unit comprising a cartridge container and a needle cap disposed between the cartridge container and the main casing, wherein the operating unit is operatively coupled to the power pack and is retractable relative to the main casing from a first position to an operating position for actuating the power pack, and thereafter the needle cap is extendable to an extended position covering the needle when the cartridge and the needle are in the injection position, a safety cap removable from an attachment position at the front end of the main casing for exposing the front portion of the operating unit, the safety cap being arranged to press a locking arm against the operating unit and lock the operating unit against retraction from the first position until the safety cap is removed, comprising, the needle cap includes a through-opening, the cartridge container includes a recess, a front end portion of the locking arm extends through the opening and is pressed by the safety cap to engage with the recess of the cartridge container, an auto-injector.

2. The auto-injector according to claim 1, wherein the safety cap includes a rib or other inwardly projecting structure for pressing the locking arm against the operating unit to lock the operating unit against retraction from the first position until the safety cap is removed.

3. The auto-injector according to claim 1, wherein the operating unit and the locking arm are lockably engaged when the safety cap is in the attachment position and are free or biased to disengage from the lock when the safety cap is removed.

4. The auto-injector according to claim 1, wherein the cartridge container includes a recess on its outer surface, and the locking arm is pressed by the safety cap to engage with the recess when the safety cap is in the attachment position.

5. The auto-injector according to claim 4, wherein the locking arm is free or biased to spread outwardly from engagement with the recess when the safety cap is removed.

6. The automatic syringe according to claim 1, wherein the front part of the actuating unit has a circular cross-section and the safety cap has an elliptical cross-section.

7. The automatic syringe according to claim 1, wherein the safety cap and the main casing include a mechanically cooperating mechanism including a detent for releasably attaching the safety cap to the front end of the main housing.

8. The automatic syringe according to claim 1, wherein the front ends of the safety cap and the main casing have cooperating elliptical cross-sections for providing a sliding fit and re-capping of the front ends of the safety cap and the main casing.

9. The automatic syringe according to claim 1, wherein the safety cap is removable from the front end of the main casing by translation without rotation.

10. The automatic syringe according to claim 1, wherein the safety cap is re-cappable.

11. The automatic syringe according to claim 1, comprising first and second locking arms arranged at diametrically opposed positions.

12. The automatic syringe according to claim 11, wherein the safety cap, when in the attached position, presses the first and second locking arms into respective recesses of the cartridge container, extends through respective through-openings of the needle cover, and is arranged to lock the actuating unit against retraction from the first position until the safety cap is removed.

13. The automatic syringe according to claim 1, wherein the locking arm has a front end enlarged to project inwardly.

14. The main casing includes a window opening and further includes a transparent window piece inserted into the main casing to close the window opening. A locking arm projecting forward is optionally integrally formed with the window piece. The main casing includes a pair of diametrically opposed window openings, the transparent window pieces are inserted into the respective window openings, and each window piece includes a locking arm projecting forward. The automatic syringe according to claim 1.

15. The automatic syringe according to claim 1, wherein the actuating unit includes 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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