Autoinjector

Abstract

An autoinjector (1) comprising: a housing (10) extending along a longitudinal axis A and configured to receive a medical container (100); a needle cover (5) coupled to and axially movable relative to the housing (10) between a first extended position, a retracted position, and a second extended position in which the needle cover (5) is moved rearward in a distal direction to shield the injection needle (103). The autoinjector (1) further comprises: a plunger rod (2) axially movable within the housing (10) between a storage position, an activation position proximal to the storage position, and an end-of-injection position distal to the storage position and the activation position; biasing means for biasing the plunger rod (2) in a distal direction towards an injection end position; and a lock (3) for distally blocking the plunger rod (2) in the storage position prior to activation of the autoinjector (1). The lock (3) comprises a first blocking member (31) radially movable between a blocking position in which said first blocking member (31) prevents distal movement of the plunger rod (2) relative to the lock (3) and a release position to allow distal movement of the plunger rod (2) relative to the lock (3). The retaining member (4) is fixed to the housing (10) for retaining the first blocking member (31) of the locking member (3) in the blocking position, the retaining member (4) comprising a lateral abutment surface (40) for radially abutting against the locking member (3) such that the first blocking member (31) of the locking member (3) is blocked in the blocking position, and the holder (4) comprises a proximal shoulder (41) for axially abutting against a second blocking member (33) of the locking member (3). The locking member (3) is axially movable together with the plunger rod (2) relative to the holding member (4) between a storage position in which the first blocking member (31) is blocked in a blocking position and an activation position, such that the first blocking member (31) of the locking member (3) can be moved from the blocking position to a release position, the movement of the lock (3) from the storage position to the activation position is caused by the movement of the needle cover (5) from the first extended position to the retracted position.

Description

Technical Field

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

[0002] In the present application, the distal end of a component or device should be understood to mean the end furthest from the user's hand, while the proximal end should be understood to mean the end closest to the user's hand. Similarly, in the present application, the "distal direction" should be understood to mean the direction away from the user's hand, while the "proximal direction" should be understood to mean the direction towards the user's hand.

[0003] Auto-injection devices are designed to automatically inject a medical product into an injection site. An auto-injector typically includes a housing for receiving a medical container. The medical container has a barrel defining a reservoir for containing the medical product, the barrel having a distal end provided with an injection needle and an open proximal end for receiving a plunger rod for pushing a stopper. The open proximal end is typically provided with a flange.

[0004] The auto-injector further includes a safety shield mechanism that moves from an extended position to a retracted position to shield or expose the needle, and an injection mechanism for automatically injecting the drug into the injection site. The injection mechanism typically includes a plunger rod for pushing the stopper inside the barrel of the medical container and an initial compression spring for moving the plunger in the distal direction. A locking device is provided for holding the plunger rod in an initial position in which, despite the action of the compression spring, the plunger rod is axially blocked. A release member is typically arranged to release the plunger from the locking device and allow the spring to push the plunger rod in the distal direction to effect the injection. It is required that the safety shield move a predetermined displacement towards the retracted position to allow the release member to unlock the locking device and release the plunger rod.

[0005] Document EP2921191 discloses a device for automatically injecting a medical product into an injection site. The device includes a two-component assembly having an upper sub-assembly assembled to a lower sub-assembly. The lower sub-assembly receives a syringe barrel provided with an injection needle. The injection needle is covered by a rigid needle shield. The device further includes a needle cap that is movable relative to the housing between an extended position and a retracted position. The plunger rod is coupled to a compression spring and is held in an initial position by a deflectable retainer of an inner cylinder. A button is arranged at the proximal end of the device for releasing the plunger rod by deflecting the retainer outwards. The button can only be activated when the needle cap has moved a predetermined distance in the proximal direction towards the retracted position. In addition, activation of the button requires the end user to press the button. That is, the end user must perform a specific additional operation to activate the device. Moreover, this specific additional operation may not be very easy since the end user must simultaneously apply a distal force to the button and hold the auto-injector pressed against his / her skin.

[0006] Accordingly, there is a need for an autoinjector that allows activation of the injection mechanism without additional action by the end user.

[0007] An autoinjector for administering a medicament is known from the document EP3384944.

[0008] To evaluate the robustness of the autoinjector, the autoinjector is subjected to drop tests in accordance with the requirements of ISO11608. These drop tests typically include dropping the autoinjector from a height of 1 m onto a horizontal floor at least once. There are three drop directions: "cap up" drop, "cap down" drop, and horizontal drop of the autoinjector. The autoinjector may be sensitive to the "cap up" drop test.

[0009] Accordingly, there is a need for an autoinjector that reduces the risk of being activated during a "cap up" drop test or any other drop.

[0010] To activate the autoinjector, the user must press the autoinjector against the injection site. The force applied by the user must overcome a predetermined activation force to activate the autoinjector and trigger the injection. However, to avoid activation during the "cap up" drop test, the activation force may be very large, and once overcome, there may no longer be any resistance, making the activation process and subsequent injection triggering rather sudden for the user.

[0011] Accordingly, there is a need to provide a more stable activation force and less sudden feedback to the end user. SUMMARY OF THE INVENTION

[0012] One aspect of the invention is an autoinjector for automatically injecting a product into an injection site, the autoinjector comprising:

[0013] a housing that extends along a longitudinal axis A and is configured to receive a medical container having a barrel that defines a reservoir for containing a medical product, the barrel having a distal end provided with an injection needle and an open proximal end configured to receive a plunger rod for pushing a stopper disposed inside the barrel;

[0014] a needle cap that is coupled to the housing and is axially movable relative to the housing between a first extended position, a retracted position, and a second extended position, in the first extended position, the needle cap at least partially shields the needle, in the retracted position, the needle cap moves proximally relative to the housing, and in the second extended position, the needle cap moves rearward in a distal direction to shield the injection needle;

[0015] A plunger rod that is axially movable within a housing between a storage position, an activation position proximal to the storage position, and an injection end position distal to the storage position and the activation position, the plunger rod being configured to push a stopper when moving from the activation position to the injection end position so as to expel a medical product;

[0016] A biasing device for biasing the plunger rod in a distal direction towards the injection end position;

[0017] A locking member for blocking the plunger rod distally in the storage position before activation of the auto-injector, wherein the locking member includes a first blocking member that is radially movable between a blocking position and a release position, in the blocking position, the first blocking member axially abuts against a distal abutment surface of the plunger rod so as to prevent the plunger rod from moving distally relative to the locking member, and in the release position, the first blocking member is away from the distal abutment surface of the plunger rod to allow the plunger rod to move distally relative to the locking member;

[0018] A retaining member fixed to the housing for holding the first blocking member of the locking member in the blocking position, the retaining member including a lateral abutment surface for radially abutting against the locking member such that the first blocking member of the locking member is blocked in the blocking position, and the retaining member includes a proximal shoulder for axially abutting against a second blocking member of the locking member.

[0019] Wherein the locking member is axially movable relative to the retaining member together with the plunger rod between the storage position and an activation position proximal to the storage position, in the storage position, the locking member radially abuts against the lateral abutment surface of the retaining member such that the first blocking member is blocked in the blocking position, and in the storage position, a second locking member of the locking member axially abuts against the proximal shoulder of the retaining member such that the retaining member blocks the locking member distally in the storage position, in the activation position, the locking member is away from the lateral abutment surface of the retaining member such that the first blocking member of the locking member can move from the blocking position to the release position, and the movement of the locking member from the storage position to the activation position is caused by the needle cap moving from a first extended position to a retracted position.

[0020] Accordingly, the autoinjector of the present invention allows the plunger rod to move towards the injection end position, and the end user does not need to perform any further action other than pressing the needle cap against the injection site. In addition, the biasing device opposes the movement of the locking member from the storage position to the activation position and thus defines the activation force. Accordingly, the activation force is more stable, and this prevents the autoinjector from being inadvertently activated during a drop test or any accidental drop. When the end user applies the needle cap to the injection site, the end user can also feel the resistance of the biasing device, and this resistance persists from the storage position of the locking member to the activation position, which provides the end user with continuous tactile feedback that the activation process is in progress until the autoinjector is activated, i.e., the biasing device and the plunger rod are released, which initiates the injection process.

[0021] The autoinjector of the present invention may also include some or all of the following features.

[0022] In one embodiment, the first blocking member defines a proximal abutting surface for axially abutting against the distal abutting surface of the plunger rod, and the proximal abutting surface of the first blocking member and / or the distal abutting surface of the plunger are inclined. The first blocking member may move to a release position under the action of the pressure transmitted by the biasing device to the plunger rod. Preferably, the shapes of the distal abutting surface of the plunger rod and the abutting surface of the first blocking member are complementary, for example, a truncated conical shape. The locking member may include two diametrically opposed first blocking members and / or two diametrically opposed second blocking members. The holding member may include two diametrically opposed lateral abutting surfaces. The inner diameter defined between the two lateral abutting surfaces is smaller than the diameter of the larger diameter portion of the holding member.

[0023] In one embodiment, the first blocking member is disposed on the inner side of the axially extending flexible leg of the locking member, and the outer side of the flexible leg defines an outer abutting surface configured to abut against the lateral abutting surface of the holding member when the locking member is in the storage position. The outer abutting surface may be defined by a radially outwardly protruding portion. The radially outwardly protruding portion may define a guiding proximal surface, and the guiding proximal surface may be inclined relative to the longitudinal axis A to facilitate the insertion of the locking member into the interior of the holding member in the proximal direction. The flexible leg may be elastically deformable. The flexible leg has a fixed proximal end and a free distal end.

[0024] In one embodiment, the first blocking member is located at the distal end of the flexible leg, and the flexible leg is defined between two axial slots. The axial slots have a closed proximal end and an open distal end. This facilitates the deformation of the flexible leg between the blocking position and the release position. The locking member includes two diametrically opposed flexible legs and two pairs of axial slots defining the flexible legs. The first blocking member may be a radially inwardly protruding portion.

[0025] Possibly, the release position of the first blocking member may correspond to the deformed position of the flexible leg, while the blocking position of the first blocking member may correspond to the rest position of the flexible leg. Alternatively, the release position of the first blocking member may correspond to the rest position of the flexible leg, while the blocking position of the first blocking member may correspond to the deformed position of the flexible leg.

[0026] In one embodiment, the second blocking member is located on the outer surface of the flexible leg of the locking member. That is, on the distal portion of the locking member. The second blocking member may be in the form of a circumferentially extending rib. The axial distance between the second blocking member and the distal end of the flexible leg is less than the axial distance between the storage position and the activation position of the locking member. The second blocking member includes a distal stop configured to abut against the proximal shoulder of the retaining member when the locking member is in the storage position. The distal stop may be orthogonal to the longitudinal axis A.

[0027] In one embodiment, the locking member includes a drive leg for receiving the proximal thrust of the needle cap when the needle cap moves from the first extended position to the retracted position. The drive leg may be separated from the flexible leg through one of the two axial slots. The drive leg defines a distal abutment surface configured to abut against the needle cap when the needle cap moves from the first extended position to the retracted position. The distal abutment surface may be the farthest distal surface of the locking member. The locking member includes two diametrically opposed drive legs. Preferably, one or more drive legs and one or more flexible legs of the locking member are circumferentially distributed at 90° to each other. The drive legs may be located distally of the flexible legs. Possibly, the locking member includes an outwardly extending radial arm that connects the drive leg to the outer surface of the lateral wall of the locking member. The outwardly extending radial arm may define a proximal stop that may abut against the retaining member when the locking member is in the activation position.

[0028] In one embodiment, the locking member has a cylindrical guide portion, and the retaining member has one or more cylindrical centering surfaces configured to guide the axial movement of the locking member within the retaining member between the storage position and the activation position. The retaining member may include two diametrically opposed centering surfaces. Possibly, the guide portion of the locking member is configured such that the locking member can also rotate relative to the longitudinal axis A within the retaining member. For example, the guide portion has no protrusions. The centering surfaces are located proximal to the larger diameter portion of the retaining member.

[0029] In one embodiment, the guide portion of the locking member includes an anti-rotation device for blocking the rotation of the locking member relative to the retaining member.

[0030] Possibly, the retaining member is in the form of a tubular sleeve having an open distal end and a closed proximal end, the closed proximal end being fixed to the transverse wall of the housing. The retaining member may also be connected to the lateral wall of the housing by one or more strengthening members.

[0031] In one embodiment, the proximal shoulder is disposed proximal to the one or more centering surfaces. The proximal shoulder is disposed at the proximal portion (i.e., the proximal half) of the retaining member. In this case, the proximal portion of the radially inwardly projecting portion may be inclined relative to the longitudinal axis A.

[0032] Possibly, the retaining member includes an axial notch for receiving the drive leg of the locking member when the locking member is in the activated position. The axial notch may have an open distal end and a closed proximal end, the closed proximal end being defined by a distal stop, which may be configured to abut against the proximal stop of the drive leg.

[0033] In one embodiment, the lateral abutment surface of the retaining member is defined by a radially inwardly projecting portion and is located proximal to the radially inwardly projecting portion. The retaining member has a larger diameter portion configured to receive the first blocking member when the first blocking member of the locking member moves to the release position. That is, the larger diameter portion provides space for the outward deformation of the locking member. The radially inwardly projecting portion may be disposed at the distal end of the retaining member. The diameter of the larger diameter portion of the retaining member is greater than the diameter defined between the lateral abutment surfaces. The larger diameter portion is disposed proximal to the lateral abutment surfaces.

[0034] In one embodiment, the proximal shoulder of the retaining member is located on the proximal portion of the radially inwardly projecting portion of the retaining member. Thus, the proximal shoulder may be located distal to the centering surface.

[0035] In one embodiment, the second blocking member is an elastically deformable tab. The second blocking member may be remote from the flexible leg of the locking member. The second blocking member may be circumferentially offset from the first blocking member (i.e., the second blocking member may not be axially aligned with the first blocking member), but may be aligned with the drive leg. The second blocking member may be located in the proximal portion of the locking member (i.e., in the proximal half). The second blocking member includes a distal stop configured to abut against the proximal shoulder of the retaining member when the locking member is in the storage position. The distal stop may be orthogonal to the longitudinal axis A.

[0036] In one embodiment, the housing has a receiving wall configured to laterally hold the proximal end of the biasing device. The receiving wall may be in the form of an annular rib projecting distally from the transverse wall forming the distal end of the housing. Preferably, the receiving wall and the transverse wall of the housing are made of a single piece.

[0037] In one embodiment, the retainer and the housing are made of a single piece. Alternatively, the retainer and the housing are two different components, and the proximal end of the retainer is fixed to the housing by any suitable means (e.g., a clamping device, a friction fit, or gluing). In one embodiment, the transverse wall and the lateral wall of the housing are made of a single piece. In another embodiment, the transverse wall and the lateral wall of the housing are made of two different components, and the two different components are fixed to each other by any suitable means (e.g., a clamping device, a friction fit, or gluing). The transverse wall is formed to close the cap at the proximal end of the housing.

[0038] Possibly, the plunger rod extends within the biasing device. Alternatively, the biasing device extends inside the plunger rod.

[0039] In one embodiment, the movement of the locking member from the storage position to the activation position is resisted only by the biasing device. There are no bumps or protrusions that impede the movement of the locking member from the storage position to the activation position. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The invention and the advantages brought by it will be clearly presented by the following detailed description with reference to the following drawings:

[0041] - Figure 1A is a perspective view of an auto-injector according to an embodiment of the present invention,

[0042] - Figure 1B is a top view of an auto-injector according to an embodiment of the present invention,

[0043] - Figure 2 is an exploded view of an auto-injector according to an embodiment of the present invention,

[0044] - Figure 3 is according to Figure 2 a perspective view of the top body of an auto-injector according to an embodiment of

[0045] - Figure 4A and Figure 4B is according to Figure 2 a perspective view of the locking member of an auto-injector according to an embodiment of

[0046] - Figure 5A and Figure 5B is Figure 2 of the auto-injector respectively along Figure 1B lines A-A and B-B of

[0047] - Figure 6A and 6B is Figure 2 of the auto-injector respectively along Figure 1BCross-sectional views of line A-A and line B-B, with the locking member and the plunger rod in the activated position,

[0048] - Figure 7 is a perspective view of the top body of an auto-injector according to another embodiment of the present invention,

[0049] - Figure 8A and Figure 8B is a perspective view of the locking member of an auto-injector according to an embodiment of Figure 7 the present invention,

[0050] - Figure 9A and Figure 9B are cross-sectional views of an auto-injector according to an embodiment of Figure 7 the present invention, respectively, along line A-A and line B-B of Figure 1B the present invention, with the locking member and the plunger rod in the storage position,

[0051] - Figure 10A and Figure 10B are cross-sectional views of an auto-injector according to an embodiment of Figure 7 the present invention, respectively, along line A-A and line B-B of Figure 1B the present invention, with the locking member and the plunger rod in the activated position,

[0052] - Figure 11A and Figure 11B are a cross-sectional view and a perspective view of the plunger rod of an auto-injector according to an embodiment of the present invention, respectively. Detailed Description

[0053] The different features of the embodiments can be combined and used together with other embodiments, provided that the combined components do not conflict with or interfere with the operation of the device and components. The wording and terminology used herein are for descriptive purposes and should not be construed as limiting. As used herein, "comprising", "including" or "having" and their variations are intended to cover the items listed hereinafter and their equivalents as well as other items. Unless otherwise limited, the terms "connected", "coupled" and "mounted" and their variations are used broadly and cover direct and indirect connections, couplings and mountings. Additionally, the terms "connected" and "coupled" and their variations are not limited to physical or mechanical connections or couplings. As used herein, the singular forms "a", "an" and "the" are also intended to include the plural forms, unless the context clearly dictates otherwise. As used herein, the term "and / or" includes any and all combinations of one or more of the related listed items. It should be understood that although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish between the various elements. For example, without departing from the scope of the present disclosure, the first element may be referred to as the second element, and similarly, the second element may also be referred to as the first element.

[0054] Reference Figure 1A and Figure 1B shows an auto - injector 1 according to an embodiment of the present invention. The auto - injector 1 is designed to automatically inject a product into an injection site. The auto - injector 1 extends along a longitudinal axis A. The auto - injector 1 includes a housing 10, which includes a top body 10A and a bottom body 10B, and the top body and the bottom body are assembled to each other by any suitable fixing means (e.g., snap - fit means). The housing 10 has a proximal end 11 and an opposite distal end 12. A cap 19 is removably attached to the distal end 12. The top body 10A has a cylindrical side wall 13 and a transverse wall 14, and the transverse wall forms a closed and fixed proximal end 11 of the housing 10. As shown herein, the transverse wall 14 and the side wall 13 of the housing 10 are made of a single piece. In an alternative embodiment (not shown), the transverse wall 14 and the side wall 13 of the housing 10 can be made of two different components, which are fixed to each other by any suitable means (e.g., snap - fit means, friction fit, or gluing).

[0055] Figure 2 shows an exploded view of the auto - injector 1. The bottom body 10B is configured to receive a medical container 100, such as a syringe. For example, the medical container 100 can be a pre - filled syringe. The medical container 100 has a tubular barrel 101, which defines a reservoir for containing the medical product to be injected. The barrel 101 has a distal end 102( Figure 6B ) provided with an injection needle 103 and a needle guard 104 removably attached to the distal end 102, and the needle guard is used to protect and seal the injection needle 103. The barrel 101 has an open proximal end 105, which can be provided with a flange 106, and the open proximal end is configured to receive a plunger rod 2 pushed in the distal direction by a biasing means, and the biasing means can be in the form of an injection spring 6. The injection spring 6 has a distal end 61 abutting against a radial flange 21 of the plunger rod 2 and a proximal end 60 abutting against the housing 10 (more particularly, against the transverse wall 14). A ring 108 can be fixed to the proximal end 105 of the barrel 101.

[0056] The plunger rod 2 is configured to push a stopper 107( Figure 6B ) disposed inside the barrel 101, so as to discharge the medical product. The plunger rod 2 includes a distal abutting surface 20, the function of which will be described below. The plunger rod 2 can be in a storage position( Figures 5A - 5B , Figures 9A - 9B ) inside the housing 10, an activation position proximal to the storage position( Figures 6A - 6B , Figures 10A - 10B) and axially move between a storage position and an injection end position (not shown) that is distal relative to the activation position. In the injection end position, the plunger rod 2 can press the stopper 107 against the distal end of the reservoir formed by the barrel 101.

[0057] The auto-injector further includes a needle cap 5 disposed within the bottom body 10B. The needle cap 5 has a distal end 50 designed to press against an injection site (e.g., the user's skin), a radial tab 52 for engaging with a first slot 70 of the cam 7, and a proximal push surface 51 for abutting against the locking member 3, which will be explained in more detail below. The contact between the needle cap 5 and the locking member 3 can be direct, i.e., without any intermediate components. The proximal push surface 51 can extend circumferentially away from the top surface of the tab 52, and the top surface of the tab can define a radial portion of the push surface 51 to ensure abutment between the needle cap 5 and the locking member 3. The needle cap 5 is axially movable relative to the housing 10 along the longitudinal axis A between a first extended position (pre-use position, Figures 5A - 5B , Figures 9A - 9B ), a retracted position proximal to the first extended position ( Figures 6A - 6B , Figures 10A - 10B ), and a second extended position (safe position, not shown). In the first extended position, the needle cap 5 at least partially or completely shields the injection needle 103. In the retracted position, the needle cap 5 activates the auto-injector 1 and thus triggers the injection. In the second extended position, the needle cap 5 moves backward in the distal direction to safely shield the injection needle 103. The movement of the needle cap 5 from the first extended position to the retracted position is caused by the user pressing the distal end 50 of the needle cap 5 against the injection site. The movement of the needle cap 5 from the retracted position to the safe position is caused by the safety spring 8 pushing the needle cap 5 backward in the distal direction when the user removes the injection needle 103 from the injection site.

[0058] As Figure 2As shown, the auto-injector 1 may include a cam 7. The cam 7 is in the form of a cylindrical ring provided with a first slot 70 and a second slot 71. The first slot 70 has an inclined portion 701 extending between a first end 704 and a second end 705, a transverse portion 702 extending from the second end 705 to a third end 706, and an axial portion 703 extending from the third end 706 to a fourth end 707. The first slot 70 is engaged by a radial tab 52 of the needle cap 5 which is located at the first end 704 when the needle cap 5 is in the first extended position, and is located at the second end 705 and the third end 706 when the needle cap 5 is in the retracted position; and is close to or located at the fourth end 707 when the needle cap 5 is in the safe position. The second slot 71 includes an axial portion 710 which includes a proximal shoulder 711; and an inclined portion 712 extending from the proximal shoulder 711. When the needle cap 5 is in the first extended position, the second slot 71 is engaged by a ring 108 which extends in the axial portion 710. The cam 7 is pivotally mounted inside the housing 10. The rotation of the cam 7 is first caused by the radial tab 52 sliding against the inclined portion 701 when the needle cap 5 moves from the first extended position to the retracted position, and then by the ring 108 sliding against the inclined portion 712 when the injection spring 6 pushes the ring 108 and the medical container 100 distally together. The second rotation of the cam 7 causes the radial tab 52 to move from the second end 705 to the third end 706, such that when the needle cap 5 moves from the retracted position to the safe position, it allows the radial tab 52 to slide in the axial portion 703.

[0059] Reference Figure 2 and Figures 4A - 4B , the auto-injector 1 includes a locking member 3. The locking member 3 is arranged inside the top body 10A for blocking the plunger rod 2 distally in the storage position before the auto-injector 1 is activated. The locking member 3 may be in the form of a tubular sleeve. The locking member 3 may have a cylindrical side wall 30 having an inner surface 300 and an outer surface 301. The inner surface 300 defines a lumen 302 for receiving the plunger rod 2 and a biasing device. The lumen 302 has a proximal end 303 and an opposite distal end 305, the proximal end may define a proximal opening 304 to allow the plunger rod 2 and the biasing device to be inserted inside the locking member 3, and the distal end may define a distal opening 306 to allow the plunger rod 2 to extend outside the locking member 3 when the plunger rod 2 moves from the activation position to the end-of-injection position. A first blocking member 31 may extend at the distal end 305 of the lumen 302.

[0060] The locking member 3 is arranged inside the holding member 4 and is movable relative to the holding member 4 together with the plunger rod 2 between a storage position ( Figures 5A - 5B ) and an activation position proximal to the storage position ( Figures 6A - 6B) axially moves therebetween. In the storage position, the locking member 3 prevents the plunger rod 2 from moving to the injection end position. In the activation position, the locking member 3 no longer prevents the plunger rod 2 from moving to the injection end position. In the activation positions of both the locking member 3 and the plunger rod 2, the biasing device can be fully compressed.

[0061] The locking member 3 includes a first blocking member 31 that is radially deformable between a blocking position and a release position. In the blocking position, the first blocking member 31 axially abuts against the distal abutment surface 20 of the plunger rod 2 to prevent the plunger rod 2 from moving distally. In the release position, the first blocking member 31 is away from the distal abutment surface 20 of the plunger rod 2 to allow distal movement towards the injection end position. The top body 10A includes a holding member 4( Figure 5A ) which includes a lateral abutment surface 40 for holding the first blocking member 31 of the locking member 3 in the blocking position.

[0062] Reference Figures 4A - 4B , the first blocking member 31 is in the form of a radially inwardly projecting portion that projects from the inner surface 300 of the locking member 3, and more particularly, from the inner surface of the flexible leg 311 of the locking member 3. The first blocking member 31 defines a proximal abutment surface 310 for axially abutting against the distal abutment surface 20 of the plunger rod 2, thereby axially blocking the plunger rod 2 in the storage position before the auto-injector 1 is activated. The proximal abutment surface 310 can be inclined. The distal abutment surface 20 of the plunger rod 2 can also be inclined; preferably, the distal abutment surface 20 of the plunger rod 2 and the abutment surface of the first blocking member 31 are complementary in shape, for example, in a frustoconical shape. This facilitates the movement of the first blocking member 31 from the blocking position to the release position.

[0063] The locking member 3 can include two pairs of axial slots 312, each pair of axial slots 312 defining a flexible leg 311 from which the first blocking member 31 projects. The first blocking member 31 can be located at the distal end 316 of the flexible leg 311. The axial slots 312 have a closed proximal end 313 and an open distal end 314. This facilitates the deformation of the flexible leg 311 between the blocking position and the release position. The flexible leg 311 has a fixed proximal end 317.

[0064] It is conceivable that the release position of the first blocking member 31 may correspond to the deformed position of the flexible leg 311, while the blocking position of the first blocking member 31 may correspond to the rest position of the flexible leg 311. Therefore, the movement of the first blocking member 31 from the blocking position to the release position is caused by the distal pressure of the biasing device pushing the distal abutment surface 20 of the plunger rod 2 against the first blocking member 31. In another embodiment, the release position of the first blocking member 31 may correspond to the rest position of the flexible leg 311, while the blocking position of the first blocking member 31 may correspond to the deformed position of the flexible leg 311. In this case, the movement of the first blocking member 31 from the blocking position to the release position may be due to the elastic leg automatically returning to its natural rest position.

[0065] Still referring to Figures 4A - 4B , the locking member 3 may include a driving leg 32 for abutting against the proximal pushing surface 51 of the needle cap 5 when the needle cap 5 moves from the first extended position to the retracted position. Therefore, the driving leg 32 includes a distal abutment surface 320, and the proximal thrust of the needle cap 5 is received by the distal abutment surface. The distal abutment surface 320 may be the farthest surface of the locking member 3. The driving leg 32 may be radially offset relative to the flexible leg 311. Therefore, the locking member 3 may include a radially extending arm 321 that connects the driving leg 32 to the side wall of the locking member 3. The radially extending arm 321 may define a proximal stop 322 that may abut against the retaining member 4 when the locking member 3 is in the activated position. In the storage position of the locking member 3 and in the first extended position of the needle cap 5, there may be an axial gap between the proximal pushing surface 51 of the needle cap 5 and the driving leg 32 of the locking member 3.

[0066] Referring to Figure 5A , the locking member 3 has an outer abutment surface 315 that is radially opposite to the first blocking member 31, and the outer abutment surface is configured to abut against the side abutment surface 40 of the retaining member 4 when the locking member 3 is in the storage position. The abutment between the outer abutment surface 315 of the flexible leg 311 and the side abutment surface 40 of the retaining member 4 holds the first blocking member 31 in the blocking position. Referring to Figure 9A , the outer abutment surface 315 may be defined by a radially outward protrusion. The radially outward protrusion may define a guiding proximal surface 42 that may be inclined relative to the longitudinal axis A to facilitate the insertion of the locking member 3 into the retaining member 4 in the proximal direction.

[0067] The distal end 316 of the flexible leg 311 may include a chamfer 318 to facilitate the passage of the first blocking member 31 from the blocking position to the release position.

[0068] Referring to Figures 4A - 4B , Figures 5A - 5B andFigures 6A - 6B , the locking member 3 includes a second blocking member 33 which is configured to block the locking member 3 distally in the storage position. The second blocking member 33 may be located on the outer surface of the flexible leg 311 and may be in the form of a circumferentially extending rib. The axial distance between the second blocking member 33 and the distal end 316 of the flexible leg 311 is less than the axial distance between the storage position and the activation position of the locking member 3. The second blocking member 33 includes a distal stop 330 which is configured to abut against the proximal shoulder 41 of the retaining member 4 when the locking member 3 is in the storage position ( Figure 5A ).

[0069] As Figures 4A - 4B shown, the outer surface of the lateral wall of the locking member 3 may define a cylindrical outer surface which forms a guiding portion 307 configured to guide the axial movement of the locking member 3 within the retaining member 4 between the storage position and the activation position. The guiding portion 307 is configured to slide against the retaining member 4. In Figures 4A - 4B the embodiment, the guiding portion 307 is configured such that the locking member 3 can also rotate relative to the longitudinal axis A within the retaining member 4. For example, the guiding portion 307 has no protrusions. This allows the locking member 3 to be assembled into the retaining member 4 by translation and then rotation.

[0070] Figure 3 , Figures 5A - 5B and Figures 6A - 6B show the retaining member 4. The retaining member 4 may be in the form of a tubular sleeve axially extending within the housing 10. The retaining member 4 has a cylindrical lateral wall 43 which defines an outer surface 430 and an inner surface 431. The outer surface 430 may be connected to the lateral wall 13 of the housing 10 by one or more strengthening members 15. The strengthening members 15 may be axially extending walls which are alongside the inner surface 16 of the housing 10 and the outer surface of the retaining member 4. The strengthening members 15 may be regularly distributed around the longitudinal axis A and may extend within a virtual longitudinal plane including the longitudinal axis A. For example, the autoinjector 1 has four strengthening members 15, but the number and shape of the strengthening members may vary.

[0071] The inner surface 431 of the retaining member 4 defines a lumen 432 which has a closed proximal end 433 and an open distal end 434. The proximal end 433 may be closed by the transverse wall 14 of the housing 10. The open distal end 434 may be configured to allow the locking member 3 and / or the plunger rod 2 and the biasing means to be axially inserted into the retaining member 4. The open distal end 433 is also configured to allow the plunger rod 2 to extend out of the retaining member 4 when the autoinjector 1 is activated, i.e., when the plunger rod 2 moves from the activation position to the injection end position under the action of the distally applied pressure by the biasing means.

[0072] The inner cavity of the retaining member 4 includes two cylindrical centering surfaces 435 which are configured to guide the axial movement of the locking member 3 inside the retaining member 4 and, if necessary, to guide its rotation. The cylindrical centering surfaces 435 thus engage with the mounting portion of the locking member 3; they may have complementary shapes. In the illustrated embodiment, the retaining member 4 includes two diametrically opposed centering surfaces 435. The diameter between the two centering surfaces 435 may be smaller than the diameter of the remainder of the inner cavity of the retaining member 4; the largest of said diameters is configured to allow the locking member 3 to move from the storage position to the release position inside the retaining member 4. As can be seen in Figure 5A and Figure 6A , the inner cavity of the retaining member 4 provides space for allowing the flexible feet 311 of the locking member 3 to deform outwardly from the blocking position to the release position.

[0073] Referring to Figure 5A and Figure 6A , the retaining member 4 includes a lateral abutment surface 40 which is used to radially abut against the first blocking member 31, more particularly against the outer abutment surface 315 of the locking member 3, such that as long as the locking member 3 is in the storage position, the first blocking member 31 is blocked in the blocking position. The lateral abutment surface 40 may be defined by a radially inwardly projecting portion 45 which projects from the inner surface 431 of the retaining member 4. The radially inwardly projecting portion 45 may be arranged at the distal end 434 of the retaining member 4. When the locking member 3 moves to the activation position, the lateral abutment surface 40 of the retaining member 4 no longer abuts against the first blocking member 31, such that the first blocking member 31 of the locking member 3 can be deflected outwardly to the release position.

[0074] The retaining member 4 further includes a proximal shoulder 41 for axially abutting against the second blocking member 33 of the locking member 3. The proximal shoulder 41 may be defined by the proximal portion of the radially inwardly projecting portion 45. In the storage position, the second blocking member 33 of the locking member 3 abuts axially against said proximal shoulder 41. In the activation position, the second blocking member 33 of the locking member 3 may move axially away from the proximal shoulder 41.

[0075] In the Figures 3 to 6B embodiment, the assembly of the locking member 3 inside the retaining member 4 is accomplished by the following operations: axially inserting the locking member 3 inside the retaining member 4 with the second blocking member 33 of the locking member 3 circumferentially offset from the radially inwardly projecting portion 45 of the retaining member 4 such that the second blocking member 33 can move proximally past the radially inwardly projecting portion 45 and then rotating the locking member 3 inside the retaining member 4 such that the second blocking member 33 faces axially towards the radially inwardly projecting portion 45. Thus, the second blocking member 33 can abut against the proximal shoulder 41 of the retaining member 4 to block the locking member 3 in the storage position.

[0076] AsFigure 3 As shown, the retaining member 4 may include one or more axial cuts 46 for receiving the drive leg 32 of the locking member 3. The axial cuts 46 may have an open distal end 460 and a closed proximal end 461, and the closed proximal end defines a distal stop 462, which may be configured to abut against the proximal stop of the drive leg 32 when the locking member 3 moves in the proximal direction. In any case, the axial gap between the proximal stop of the drive leg 32 of the locking member 3 in the storage position and the distal stop 462 of the cut 46 is equal to or greater than the axial distance that the locking member 3 needs to travel from the storage position to the activation position.

[0077] In the illustrated embodiment, the retaining member 4 and the housing 10 are made of a single piece. Alternatively, the retaining member 4 and the housing 10 may be two different components, and the proximal end 433 of the retaining member 4 may be fixed to the housing 10 by any suitable means (e.g., snap-fit device, friction fit, or gluing).

[0078] As visible in Figure 3 the housing 10 may have a receiving wall 17 configured to laterally hold the proximal end 60 of the biasing device. The receiving wall 17 may be in the form of an annular rib that projects distally from the transverse wall 14 of the housing 10. Preferably, the receiving wall 17 and the transverse wall 14 of the housing 10 are made of a single piece. The receiving wall 17 may define a distal stop 18 configured to abut against the locking member 3 when the locking member 3 moves in the proximal direction. In any case, the axial gap between the proximal end 303 of the locking member 3 in the storage position and the receiving wall 17 or the transverse wall 14 is equal to or greater than the axial distance that the locking member 3 needs to travel from the storage position to the activation position.

[0079] Figure 7 and Figures 8A - 8B and Figures 9A - 9B and Figures 10A - 10B Another embodiment is shown. As clearly shown in Figure 8A or 8B, the second blocking member 33 of the locking member 3 may herein be in the form of an axially extending tab rather than a circumferential rib. Additionally, the tab may be located in the proximal portion of the locking member 3 (i.e., in the proximal half). The second blocking member 33 (tab) includes a distal stop 330 configured to Figures 5A - 5B and Figures 9A - 9B) abuts against the proximal shoulder 41 of the holder 4 at that time. The tab may include a first end 331 and a second end 332. The first end is fixed to the outer surface 301 of the locking member 3, and the second end may be a free end and define a distal stop 330. The first end 331 may be located proximally, while the second end 332 is located distally. The tab may include an inclined portion 333 and an axial portion 334. The inclined portion may extend from the first end 331 and be inclined with respect to the longitudinal axis A, and the axial portion may extend from the inclined portion 333 to the second end 332 parallel to the longitudinal axis A. The second blocking member 33 (tab) may be elastically deformed between a retracted position (not shown) and an extended position ( Figures 8A - 8B , Figure 9B , Figure 10B ). In the retracted position, the tab buckles radially inward to allow the locking member 3 to be inserted into the holder 4 in the proximal direction. In the extended position, the tab extends radially outward from the retracted position such that the distal stop 330 of the tab faces axially the proximal shoulder 41 of the holder 4, and when the locking member 3 is in the storage position, the tab may abut against the proximal shoulder 41. The lateral wall of the locking member 3 may include a notch 335, which provides space for the deformation of the second blocking member 33 in the retracted position.

[0080] Still referring to Figures 8A - 8B , the guiding portion 307 of the locking member 3 may include an anti-rotation device for blocking the rotation of the locking member 3 relative to the holder 4. Thus, the first blocking member 31 cannot be moved away from the holder 4 by rotation. Preferably, the anti-rotation device may be configured to rotationally position the locking member 3 relative to the holder 4 before assembly, that is, align the first blocking member 31 of the locking member 3 with the lateral abutting surface 40 of the holder 4 and align the second blocking member 33 of the locking member 3 with the proximal shoulder 41 of the holder 4. The anti-rotation device may be in the form of an axially extending rib 308 that projects from the outer portion of the lateral wall of the locking member 3. The axially extending rib 308 defines a straight radial stop 309s that abuts against the holder 4, and more particularly, against the corresponding abutting surfaces on both sides of the centering surface 435, for blocking the rotation of the locking member 3 relative to the holder 4.

[0081] As Figure 7 , Figure 9B , Figure 10B shown, the proximal shoulder 41 of the holder 4 is arranged at the proximal portion (i.e., proximal half) of the holder 4. In this case, the proximal portion of the radially inward protrusion 45 of the holder 4 may define a ramp surface 463 that is inclined with respect to the longitudinal axis A.

[0082] The assembly of the locking member 3 inside the retaining member 4 is accomplished simply by translating the locking member 3 inside the retaining member 4. The second blocking member 33 is forced into the retracted position by the inclined portion abutting against the distal stop 462 and then slides against the centering surface 435 of the retaining member 4 until the second blocking member reaches the larger diameter portion 44 of the inner cavity, the diameter of which is greater than the diameter between the centering surfaces 435 of the retaining member 4. The larger diameter portion 44 of the inner cavity is separated from the centering surface 435 by the proximal shoulder 41.

[0083] Reference Figure 2 、 Figures 5A - 5B or Figures 9A - 9B , the plunger rod 2 is arranged inside the locking member 3 and, more particularly, inside the biasing means. The plunger rod 2 includes a distal end 22 and an opposite proximal end 23, the distal end being for pushing the stopper 107 inside the barrel 101 of the medical container 100, and the proximal end being remote from the transverse wall 14 of the housing 10 when the plunger rod 2 is in the storage position. In the activated position, the proximal end 23 may or may not abut against the transverse wall 14. The axial gap between the proximal end 23 of the plunger rod 2 in the storage position and the proximal end 11 of the housing 10 is equal to or greater than the axial distance that the plunger rod 2 needs to travel from the storage position to the activated position. The distal abutment surface 20 of the plunger rod 2 is defined by the distal portion of the radial flange 21. The radial flange 21 preferably extends 360° around the plunger rod 2. The distal abutment surface 20 may be inclined relative to the longitudinal axis A. Thus, the distal abutment surface 20 can deflect the first blocking member 31 under the action of the biasing means, and thus, as soon as the locking member 3 reaches the activated position, i.e., as soon as the first blocking member 31 no longer abuts against the lateral abutment surface 40 of the retaining member 4, the first blocking member 31 can immediately move from the blocking position to the release position. The opposite proximal portion of the radial flange 21 can serve as a support for the distal end of the biasing means.

[0084] In Figures 11A - 11B the other embodiment shown, the biasing means may be arranged inside the plunger rod 2 instead of extending around the plunger rod 2. The plunger rod 2 is in the form of a tubular sleeve that defines an inner cavity 25 for receiving the biasing means. The inner cavity 25 may define an open proximal end 23 that allows the biasing means to be inserted into the plunger rod 2 and a closed distal end 22 that provides support for the distal end 61 of the biasing means. The lateral wall 26 of the plunger rod 2 may include a radial opening 24 that is configured to receive the first blocking member 31 of the locking member 3. The distal abutment surface 20 may be formed by the top side portion of the opening 24.

[0085] The operation of the auto-injector 1 is described as follows.

[0086] Before the auto-injector 1 is activated, the needle cap 5 is in a first extended position, both the plunger rod 2 and the locking member 3 are in a storage position, the injection spring 6 is partially compressed, the first blocking member 31 of the locking member 3 is in a blocking position and cannot move to the release position because it abuts against the lateral abutting surface 40 of the holding member 4. In addition, the injection spring 6 holds the locking member 3 in the storage position and presses the second blocking member 33 against the proximal shoulder 41. The biasing device counteracts the inadvertent movement of the locking member 3 in the proximal direction due to a drop test or any accidental drop. The locking member 3 prevents the plunger rod 2 from moving in the distal direction ( Figures 5A - 5B and Figures 9A - 9B ). The auto-injector 1 is prevented from being activated.

[0087] The user must first withdraw the cap from the bottom body 10B. When the cap is withdrawn, the needle shield 104 is also removed. During cap removal, the ring can abut against the proximal shoulder 41 of the cam 7 to prevent the medical container 100 from moving distally.

[0088] Then, the user places the auto-injector 1 against the injection site. The distal end of the needle cap 5 abuts against the injection site. As the user presses the auto-injector 1 against the injection site, the needle cap 5 moves from the first extended position to the retracted position. The movement of the needle cap 5 in the proximal direction causes the radial tab 52 to slide against the cam 7. This causes the cam 7 to rotate such that the ring moves away from the proximal shoulder 41 and engages with the axial portion at this time. When the needle cap 5 reaches the retracted position, the radial tab 52 is located at the second end of the first slot 70.

[0089] The proximally directed movement of the needle cap 5 towards the retracted position also causes the proximal pushing surface 51 of the needle cap 5 to push against the locking member 3 (the driving leg 32 thereof), and thus overcomes the action of the injection spring 6 to push the locking member 3 together with the plunger rod 2 from the storage position to the activation position. Therefore, the first blocking member 31 moves proximally and no longer abuts against the lateral abutting surface 40 of the holding member 4 ( Figure 6A 、 Figure 10A ). At this time, the flexible leg 311 is free to deflect radially outward. Due to the distal force exerted by the injection spring 6 on the plunger rod 2 and due to the contact between the plunger rod 2 and the first blocking member 31, the flexible leg 311 deflects outward. The first blocking member 31 thus moves to the release position, that is, moves away from the distal abutting surface 20 of the plunger rod, and the distal abutting surface of the plunger rod can move towards the injection end position under the action of the injection spring 6.

[0090] The plunger rod 2 coupled to the stopper 107 first pushes the medical container 100 in the distal direction so that the injection needle 103 reaches the injection site. This movement causes the ring to slide against the inclined portion of the second slot 71, causing the cam 7 to rotate further. The radial tab 52 reaches the third end of the first slot 70; the needle cap 5 can then move distally towards the safe position. Then, the plunger rod 2 pushes the stopper 107 inside the barrel 101 to expel the medical product. When the stopper 107 finally abuts against the distal end of the reservoir defined by the barrel 101, the injection is completed. An indicator (e.g., visual, tactile, or auditory) can inform the user that the injection is complete.

[0091] Then, the user moves the auto-injector 1 away from the injection site. As the needle cap 5 moves from the retracted position to the safe position under the action of the safety spring 8, the radial tab 52 slides axially. The locking mechanism can lock the needle cap 5 in the safe position to prevent needle stick injuries.

[0092] As can be readily understood from the above description, the auto-injector 1 of the present invention allows for a reduction in the steps required to trigger an injection (the user does not need to press a button, and when the auto-injector 1 is pressed against the user's skin, the locking member 3 automatically slides to the activation position). Due to the resistance of the biasing device, inadvertent activation can be avoided, and the user can obtain continuous feedback that the activation process is underway, i.e., the auto-injector 1 is about to be activated (no hard points and sudden releases).

[0093] It should be understood that the present invention is not limited to the embodiments described above and shown in the drawings; on the contrary, those skilled in the art will recognize that many changes and modifications can be made within the scope of the appended claims.

Claims

1. An auto-injector (1) for automatically injecting a product into an injection site, the auto-injector (1) comprising: a housing (10) extending along a longitudinal axis A and configured to receive a medical container (100), the medical container having a barrel (101) defining a reservoir for containing a medical product, the barrel (101) having a distal end and an open proximal end (105), the distal end being provided with an injection needle (103), the open proximal end being configured to receive a plunger rod (2) for pushing a stopper (107) disposed inside the barrel (101), a needle cap (5) coupled to the housing (10) and axially movable relative to the housing between a first extended position, a retracted position, and a second extended position, in the first extended position, the needle cap (5) at least partially shields the injection needle (103), in the retracted position, the needle cap (5) moves proximally relative to the housing (10), in the second extended position, the needle cap (5) moves rearward in a distal direction to shield the injection needle (103), a plunger rod (2) axially movable inside the housing (10) between a storage position, an activation position proximal to the storage position, and an injection end position distal to the storage position and the activation position, the plunger rod (2) being configured to push the stopper (107) when moving from the activation position to the injection end position so as to expel the medical product, a biasing device for biasing the plunger rod (2) in a distal direction towards the injection end position, a locking member (3) for blocking the plunger rod (2) distally in the storage position before activation of the auto-injector (1), wherein the locking member (3) includes a first blocking member (31) radially movable between a blocking position and a release position, in the blocking position, the first blocking member (31) axially abuts against a distal abutment surface (20) of the plunger rod (2) to prevent the plunger rod (2) from moving distally relative to the locking member (3), in the release position, the first blocking member (31) is away from the distal abutment surface (20) of the plunger rod (2) to allow the plunger rod (2) to move distally relative to the locking member (3), a retaining member (4) fixed to the housing (10) for retaining the first blocking member (31) of the locking member (3) in the blocking position, the retaining member (4) including a lateral abutment surface (40) for radially abutting against the locking member (3) such that the first blocking member (31) of the locking member (3) is blocked in the blocking position, and the retaining member (4) includes a proximal shoulder (41) for axially abutting against a second blocking member (33) of the locking member (3), Wherein, the locking member (3) can axially move together with the plunger rod (2) relative to the holding member (4) between a storage position and an activation position proximal to the storage position. In the storage position, the locking member (3) radially abuts against the lateral abutting surface (40) of the holding member (4), such that the first blocking member (31) is blocked in the blocking position. And in the storage position, the second blocking member (33) of the locking member (3) axially abuts against the proximal shoulder (41) of the holding member (4), such that the holding member (4) blocks the locking member (3) distally in the storage position. In the activation position, the locking member (3) is away from the lateral abutting surface (40) of the holding member (4), such that the first blocking member (31) of the locking member (3) can move from the blocking position to the release position. The movement of the locking member (3) from the storage position to the activation position is caused by the movement of the needle cap (5) from the first extended position to the retracted position.

2. The autoinjector (1) according to the preceding claim, wherein, The first blocking member (31) defines a proximal abutting surface (310) for axially abutting against the distal abutting surface (20) of the plunger rod (2), and the proximal abutting surface (310) of the first blocking member (31) and / or the distal abutting surface (20) of the plunger rod (2) is inclined.

3. The autoinjector (1) according to any one of the preceding claims, wherein, The first blocking member (31) is arranged on the inner side of the axially extending flexible leg (311) of the locking member (3), and the outer side of the flexible leg (311) defines an outer abutting surface (315), which is configured to abut against the lateral abutting surface (40) of the holding member (4) when the locking member (3) is in the storage position.

4. The autoinjector (1) according to the preceding claim, wherein, The first blocking member (31) is located at the distal end of the flexible leg (311), and the flexible leg (311) is defined between two axial slots (312).

5. The autoinjector (1) according to any one of the preceding claims 3 or 4, wherein, The second blocking member (33) is located on the outer surface of the flexible leg (311) of the locking member (3).

6. The autoinjector (1) according to any one of the preceding claims, wherein, The locking member (3) includes a driving leg (32) for receiving a proximal thrust of the needle cap (5) when the needle cap (5) moves from the first extended position to the retracted position.

7. The autoinjector (1) according to any one of the preceding claims, wherein, The locking member (3) has a cylindrical guiding portion (307), and the holding member (4) has one or more cylindrical centering surfaces (435), which are configured to guide the axial movement of the locking member (3) inside the holding member (4) between the storage position and the activation position.

8. The autoinjector (1) according to the preceding claim, wherein, The guiding portion (307) of the locking member (3) includes an anti-rotation device for blocking the rotation of the locking member (3) relative to the holding member (4).

9. The autoinjector (1) according to claim 7 or 8, wherein, The proximal shoulder (41) is arranged proximal to the one or more centering surfaces (435).

10. The autoinjector (1) according to any one of the preceding claims, wherein, The lateral abutment surface (40) of the retaining member (4) is defined by a radially inward protrusion (45), and proximal to the radially inward protrusion (45), the retaining member (4) has a larger diameter portion (44) configured to receive the first blocking member (31) of the locking member (3) when the first blocking member (31) moves to the release position.

11. The autoinjector (1) according to the preceding claim, wherein, The proximal shoulder (41) of the retaining member (4) is located on the proximal portion of the radially inward protrusion (45) of the retaining member (4).

12. An autoinjector (1) according to any one of the preceding claims, wherein, The second blocking member (33) is an elastically deformable tab.

13. The autoinjector (1) according to any one of the preceding claims, wherein, The housing (10) has a receiving wall (17) configured to laterally hold the proximal end (60) of the biasing device.

14. The autoinjector (1) according to any one of the preceding claims, wherein, The retaining member (4) and the housing (10) are made of a single piece.

15. The autoinjector (1) according to any one of the preceding claims, wherein, The movement of the locking member (3) from the storage position to the activation position is only resisted by the biasing device.

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