Automatic injector
The autoinjector addresses the issues of user manipulation and drop-induced activation by incorporating a locking mechanism and biasing means for consistent actuation force and feedback, improving usability and reliability.
Patent Information
- Application Number
- JP2025528515
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-11-15
- Filing Date
- 2023-11-13
- Publication Date
- 2025-11-18
AI Technical Summary
Existing automatic injectors require additional user manipulation for actuation, are prone to inadvertent activation during drop tests, and provide abrupt feedback, making them challenging to use and unreliable.
An autoinjector design with a locking mechanism that allows actuation without additional user input, featuring a biasing means to maintain consistent actuation force and provide tactile feedback, preventing inadvertent activation during drops.
Enables actuation of the injection mechanism solely by pressing the needle cover against the injection site, ensuring consistent force and continuous feedback, thereby enhancing user experience and reliability.
Smart Images
Figure 2025537575000001_ABST
Abstract
Description
[Technical Field]
[0001] The present invention relates to an autoinjector.
[0002] In this application, the distal end of a component or device should be understood to mean the end furthest from the user's hand, and the proximal end should be understood to mean the end closest to the user's hand. Similarly, in this application, the term "distal direction" should be understood to mean the direction away from the user's hand, and the term "proximal direction" should be understood to mean the direction toward the user's hand. [Background technology]
[0003] Automatic injection devices are designed for automatically injecting a medical product into an injection site. Automatic injection devices typically include 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 with an injection needle and an open proximal end for receiving a plunger rod for pressing a stop. The open proximal end typically includes a flange.
[0004] The automatic injector also includes a safety shield mechanism that moves from an extended position to a retracted position to shield or release the needle, respectively, and an injection mechanism for automatically injecting the medical material into the injection site. The injection mechanism typically includes a plunger rod for pressing a stop within the barrel of the medical container and an initial compression spring for moving the plunger in a distal direction. A locking means is provided to maintain the plunger rod in an initial position in which it is axially blocked despite the action of the compression spring. A release member is typically positioned to release the plunger from the locking means, allowing the spring to push the plunger rod in a distal direction to perform the injection. A predetermined displacement of the safety shield toward the retracted position is required to allow the release member to unlock the locking means and release the plunger rod.
[0005] EP 2 921 191 A1 discloses a device for automatic injection of a medical product into an injection site. The device includes a two-part assembly having an upper subassembly assembled to a lower subassembly. The lower subassembly receives an injector with an injection needle. The injection needle is covered by a rigid needle shield. The device further includes a needle cover movable relative to the housing between an extended position and a retracted position. The plunger rod is coupled to a compression spring and maintained in an initial position by a deflectable retainer on an inner cylinder. A push button is positioned at the proximal end of the device to release the plunger rod by outward deflection of the retainer. Actuation of the push button is possible only when the needle cover has moved a predetermined distance proximally toward the retracted position. Furthermore, actuation of the push button requires an end user to press the push button. This means that the end user must perform a specific additional operation to activate the device. Furthermore, this operation can be challenging because the end user must simultaneously apply a distal force to the push button and hold the automatic injector against the skin.
[0006] Therefore, there is a need for an automatic injector that allows for actuation of the injection mechanism without requiring additional manipulation by the end user.
[0007] From EP 3 384 944 A1 an automatic injector for administering medicinal products is known.
[0008] To assess the robustness of power injectors, they are subjected to drop tests required by ISO 11608. These drop tests typically consist of at least one drop from a height of 1 m onto a level floor. There are three drop orientations: a "cap up" drop, a "cap down" drop, and a drop with the power injector in a horizontal position. Power injectors can be sensitive to the "cap up" drop test.
[0009] Therefore, there is a need for a power injector that reduces the risk of being activated during a "cap up" or other drop test.
[0010] To activate a power injector, a user must press the power injector against the injection site. The force exerted by the user must overcome a predetermined activation force to activate the power injector and initiate an injection. However, the activation force may be quite high to avoid activation during a "cap up" drop test, and once overcome, there may no longer be resistance, making the activation process and subsequent initiation of injection quite abrupt for the user.
[0011] Therefore, there is a need for a more consistent actuation force and less abrupt feedback to the end user. Summary of the Invention
[0012] One aspect of the present invention is an autoinjector for automatically injecting a product into an injection site, the autoinjector comprising: a housing configured to receive a medical container having a barrel extending along a longitudinal axis A and defining 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 pressing a stop disposed inside the barrel; a needle cover coupled to the housing and axially movable relative to the housing between a first extended position in which the needle cover at least partially shields the infusion needle, a retracted position in which the needle cover moves proximally relative to the housing, and a second extended position in which the needle cover moves back distally to shield the infusion needle; a plunger rod axially movable within the housing between a storage position, an actuation position disposed proximally relative to the storage position, and an injection end position disposed distally relative to the storage position and the actuation position, the plunger rod configured to press against a stop for expelling the medical product as the plunger rod moves from the actuation position to the injection end position; biasing means for biasing the plunger rod distally toward an end-of-injection position; a locking portion for distally blocking the plunger rod in a storage position prior to actuation of the automatic injector, the locking portion including a first blocking member radially movable between a blocking position in which the first blocking member abuts axially against a distal abutment surface of the plunger rod to prevent distal movement of the plunger rod relative to the locking portion, and a released position in which the first blocking member moves away from the distal abutment surface of the plunger rod to allow distal movement of the plunger rod relative to the locking portion; a retainer secured to the housing for maintaining the first blocking member of the locking portion in a blocking position, the retainer including a lateral abutment surface for radially abutting against the locking portion so that the first blocking member of the locking portion is blocked in the blocking position, and the retainer including a proximal shoulder for axially abutting against the second blocking member of the locking portion; Equipped with The locking portion is axially movable with the plunger rod relative to the retaining portion between a storage position in which the locking portion abuts radially against the lateral abutment surface of the retaining portion such that the first blocking member is blocked in the blocking position and the second blocking member of the locking portion abuts axially against the proximal shoulder of the retaining portion such that the retaining portion distally blocks the locking portion in the storage position, and an actuated position in which the locking portion is disposed proximally relative to the storage position and the locking portion is spaced from the lateral abutment surface of the retaining portion such that the first blocking member of the locking portion can move from the blocking position to the released position, and movement of the locking portion from the storage position to the actuated position is caused by movement of the needle cover from the first extended position to the retracted position.
[0013] Thus, the automatic injector of the present invention allows the plunger rod to move toward the end-of-injection position without any actuation from the end user other than pressing the injection needle cover against the injection site. Moreover, the biasing means acts against the movement of the locking portion from the stored position to the activated position, thus defining the actuation force. As a result, the actuation force is more consistent, which prevents inadvertent actuation of the automatic injector during drop testing or due to an accidental drop. The end user can also feel the resistance of the biasing means as they apply the needle cover against the injection site, and this resistance persists from the stored position to the activated position of the locking portion, providing the end user with continuous tactile feedback that the actuation process is engaged until actuation of the automatic injector, i.e., release of the biasing means and plunger rod to begin the injection process.
[0014] The automatic injector of the present invention may further include some or all of the following features.
[0015] In one embodiment, the first block member defines a proximal abutment surface for axially abutting against the distal abutment surface of the plunger rod, and the proximal abutment surface of the first block member and / or the distal abutment surface of the plunger are inclined. The first block member can be moved to the release position under pressure transmitted to the plunger rod by the biasing means. Preferably, the distal abutment surface of the plunger rod and the abutment surface of the first block member are complementary in shape, e.g., frustum-shaped. The locking portion may include two diametrically opposed first block members and / or two diametrically opposed second block members. The retaining portion may include two diametrically opposed lateral abutment surfaces. An inner diameter defined between the two lateral abutment surfaces is smaller than the diameter of the larger diameter portion of the retaining portion.
[0016] In one embodiment, the first blocking member is disposed on an inner surface of an axially extending flexible leg of the locking portion, the outer surface of the flexible leg defining an outer abutment surface configured to abut against the lateral abutment surface of the retainer when the locking portion is in the storage position. The outer abutment surface may be defined by a radially outward protrusion. The radially outward protrusion may define a guide proximal surface, which may be inclined with respect to the longitudinal axis A to facilitate proximal insertion of the locking portion within the retainer. The flexible leg may be resiliently deformable. The flexible leg has a fixed proximal end and a free distal end.
[0017] In one embodiment, the first blocking member is disposed at the distal end of the flexible leg, and the flexible leg is bounded by two axial slots. The axial slots have a closed proximal end and an open distal end. This facilitates deformation of the flexible leg between the blocked position and the released position. The locking portion includes two diametrically opposed flexible legs and two pairs of axial slots that bound the flexible legs. The first blocking member may be a radially inward protrusion.
[0018] Possibly, the released position of the first blocking member may correspond to the deformed position of the flexible legs and the blocked position of the first blocking member may correspond to the rest position of the flexible legs, or alternatively, the released position of the first blocking member may correspond to the rest position of the flexible legs and the blocked position of the first blocking member may correspond to the deformed position of the flexible legs.
[0019] In one embodiment, the second blocking member is disposed on the outer surface of the flexible leg of the locking member, i.e., on the distal end 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 retainer when the locking member is in the storage position. The distal stop may be perpendicular to the longitudinal axis A.
[0020] In one embodiment, the locking portion includes a drive leg for receiving a proximal push of the needle cover when the needle cover moves from the first extended position to the retracted position. The drive leg may be separated from the flexible leg by one of two axial slots. The drive leg defines a distal abutment surface configured to abut against the needle cover when the needle cover moves from the first extended position to the retracted position. The distal abutment surface may be the distal-most surface of the locking portion. The locking portion includes two diametrically opposed drive legs. Preferably, the drive leg(s) and flexible leg(s) of the locking portion are circumferentially distributed 90° from each other. The drive leg may be distal to the flexible leg. Possibly, the locking portion includes an outwardly extending radial arm connecting the drive leg to an outer surface of the lateral wall of the locking portion. The outwardly extending radial arms may define a proximal stop that may abut against the retainer when the lock is in the activated position.
[0021] In one embodiment, the locking portion has a cylindrical guide portion, and the retaining portion has one or more cylindrical central surfaces configured to guide axial movement of the locking portion within the retaining portion between the storage position and the actuated position. The retaining portion may include two diametrically opposed central surfaces. Possibly, the guide portion of the locking portion is configured to allow the locking portion to rotate inside the retaining portion relative to the longitudinal axis A. The central surfaces are adjacent to the larger diameter portion of the retaining portion.
[0022] In one embodiment, the guide portion of the locking portion includes anti-rotation means for blocking rotation of the locking portion relative to the retaining portion.
[0023] Possibly, the retainer is in the form of a tubular sleeve having an open distal end and a closed proximal end secured to a transverse wall of the housing. The retainer may further be connected to the transverse wall of the housing by one or more reinforcements.
[0024] In one embodiment, the proximal shoulder is disposed proximally relative to one or more central surfaces. The proximal shoulder is disposed on the proximal portion or half of the retainer. In this case, the proximal side of the radially inward projection may be angled relative to the longitudinal axis A.
[0025] Possibly, the retainer includes an axial notch for receiving the drive leg of the locking portion when the locking portion is in the activated position. The axial notch may have an open distal end and a closed proximal end bounded by a distal stop, which may be configured to abut against the proximal stop of the drive leg.
[0026] In one embodiment, the lateral abutment surfaces of the retainer are defined by radially inward protrusions, and the retainer has a larger diameter portion proximal to the radially inward protrusions configured to receive the first blocking member of the locking portion when the first blocking member is moved to the unlocked position. That is, the larger diameter portion provides space for outward deformation of the locking portion. The radially inward protrusions may be located at a distal end of the retainer. The larger diameter portion of the retainer has a diameter larger than the diameter defined between the lateral abutment surfaces. The larger diameter portion is located proximal to the lateral abutment surfaces.
[0027] In one embodiment, the proximal shoulder of the retainer is located proximal to the radially inward projection of the retainer, and the proximal shoulder may therefore be distal to the central surface.
[0028] In one embodiment, the second blocking member is an elastically deformable tab. The second blocking member may be spaced apart from the flexible legs of the locking portion. The second blocking member may be circumferentially offset from the first blocking member, i.e., not axially aligned with the first blocking member, but instead aligned with the drive legs. The second blocking member may be disposed at a proximal portion, i.e., proximal half, of the locking portion. The second blocking member includes an end stop configured to abut against the proximal shoulder of the retaining portion when the locking portion is in the storage position. The end stop may be perpendicular to the longitudinal axis A.
[0029] In one embodiment, the housing has a containment wall configured to laterally retain the proximal end of the biasing means. The containment wall may be in the form of an annular rib projecting distally from a transverse wall forming the distal end of the housing. Preferably, the containment wall and the transverse wall of the housing are made in a single piece.
[0030] In one embodiment, the retainer and housing are made from a single piece. Alternatively, the retainer and housing are two different parts, and the proximal end of the retainer is secured to the housing by any suitable means, such as, for example, clips, a friction fit, or adhesive. In one embodiment, the transverse and lateral walls of the housing are made from a single piece. In another embodiment, the transverse and lateral walls of the housing are made from two different parts secured to each other by any suitable means, such as, for example, clips, a friction fit, or adhesive. Such a transverse wall forms a cap for closing the proximal end of the housing.
[0031] In some cases, the plunger rod extends into the biasing means, or alternatively, the biasing means extends inside the plunger rod.
[0032] In one embodiment, movement of the lock from the stored position to the activated position is opposed only by a biasing means: there are no points or protrusions that impede movement of the lock from the stored position to the activated position.
[0033] The present invention and the advantages arising therefrom will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: [Brief explanation of the drawings]
[0034] [Figure 1A] FIG. 1A is a perspective view of an automatic injector according to an embodiment of the present invention. [Figure 1B] FIG. 1B is a top view of a power injector according to an embodiment of the present invention. [Figure 2] FIG. 2 is an exploded perspective view of an automatic injector according to one embodiment of the present invention. [Figure 3] 3 is a perspective view of the top body of the power injector according to the embodiment of FIG. 2. FIG. [Figure 4A] 4A is a perspective view of a locking portion of the automatic injector according to the embodiment of FIG. 2. FIG. [Figure 4B] 4B is a perspective view of a locking portion of the power injector according to the embodiment of FIG. 2. FIG. [Figure 5A] FIG. 5A is a cross-sectional view of the power injector of FIG. 2 taken along line AA of FIG. 1B, with the lock and plunger rod in the stored position. [Figure 5B] FIG. 5B is a cross-sectional view of the power injector of FIG. 2 taken along line BB of FIG. 1B, with the lock and plunger rod in the stored position. [Figure 6A] FIG. 6A is a cross-sectional view of the power injector of FIG. 2 taken along line AA of FIG. 1B, with the locking portion and plunger rod in the activated position. [Figure 6B] 6B is a cross-sectional view of the power injector of FIG. 2 taken along line BB of FIG. 1B, with the locking portion and plunger rod in the activated position. [Figure 7] FIG. 7 is a perspective view of the upper body of an automatic injector according to another embodiment of the present invention. [Figure 8A] 8A is a perspective view of a locking portion of the power injector according to the embodiment of FIG. 7. FIG. [Figure 8B] 8B is a perspective view of a locking portion of the power injector according to the embodiment of FIG. 7. FIG. [Figure 9A]9A is a cross-sectional view of the power injector according to the embodiment of FIG. 7 taken along line AA of FIG. 1B, with the lock and plunger rod in the stored position. [Figure 9B] 9B is a cross-sectional view of the power injector according to the embodiment of FIG. 7 taken along line BB of FIG. 1B, with the lock and plunger rod in the stored position. [Figure 10A] 10A is a cross-sectional view of the autoinjector according to the embodiment of FIG. 7 taken along line AA in FIG. 1B, with the locking portion and plunger rod in the activated position. [Figure 10B] 10B is a cross-sectional view of the autoinjector according to the embodiment of FIG. 7 taken along line B-B-B of FIG. 1, with the locking portion and plunger rod in the activated position. [Figure 11A] FIG. 11A is a cross-sectional view of a plunger rod of an autoinjector in accordance with an embodiment of the present invention. [Figure 11B] FIG. 11B is a perspective view of a plunger rod of an autoinjector in accordance with an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION
[0035] Different features of embodiments may be used in combination with other embodiments so long as the combined parts do not conflict with or interfere with the operation of the devices and assemblies. Phrases and terms used herein are for purposes of description and should not be considered limiting. The use of "comprises," "constitutes," or "having," and variations thereof, herein is intended to encompass the subsequently listed items and equivalents thereof, as well as additional items. Unless otherwise limited, the terms "coupled," "coupled," "attached," and variations thereof, herein are used broadly and include direct and indirect couplings, couplings, and attachments. Furthermore, the terms "coupled" and "coupled" and variations thereof are not limited to physical or mechanical couplings or connections. As used herein, the singular forms "a," "an," and "the" are 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 associated listed items. Although the terms "first," "second," etc. herein may be used to describe various elements, it will be understood that these elements should not be limited by these terms. These terms are used merely to distinguish one element from another. For example, a first element could be referred to as a second element, and similarly, a second element could be referred to as a first element without departing from the scope of the present disclosure.
[0036] 1A and 1B, shown is an automatic injector 1 according to one embodiment of the present invention. The automatic injector 1 is designed for automatic injection of a product into an injection site. The automatic injector 1 extends along a longitudinal axis A. The automatic injector 1 includes a housing 10 having a top body 10A and a bottom body 10B assembled together by any suitable fastening means, such as a 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 lateral wall 13 and a transverse wall 14 that forms the closed, fixed proximal end 11 of the housing 10. As shown here, the transverse wall 14 and the transverse wall 13 of the housing 10 are made of a single piece. In an alternative embodiment (not shown), the transverse wall 14 and the lateral wall 13 of the housing 10 may be made of two different parts secured to each other by any suitable means, such as, for example, a snap fit, a friction fit, or adhesive.
[0037] FIG. 2 is an exploded perspective view of the automatic injector 1. The base body 10B is configured to receive a medical container 100, such as a syringe. For example, the medical container 100 may be a prefilled syringe. The medical container 100 has a tubular barrel 101 defining a reservoir for containing a medical product to be injected. The barrel 101 has a distal end 102 (FIG. 6B) provided with an injection needle 103, and a needle shield 104 removably attached to the distal end 102 to protect and seal the injection needle 103. The barrel 101 has an open proximal end 105 configured to receive a plunger rod 2 that may be provided with a flange 106 and that is biased distally by a biasing means, which may be in the form of an injection spring 6. The injection spring 6 has a distal end 61 that abuts against the plunger rod 2 (the radial flange 21 of the plunger rod 2) and a proximal end 60 that abuts against the housing 10 (more specifically, the transverse wall 14). The ring 108 may be secured to the proximal end 105 of the barrel 101 .
[0038] The plunger rod 2 is configured to press against a stop 107 (FIG. 6B) disposed within the barrel 101, thereby expelling the medical product. The plunger rod 2 includes a distal abutment surface 20, the function of which will be described below. The plunger rod 2 is axially movable within the housing 10 between a storage position (FIGS. 5A-5B, 9A-9B), an actuation position (FIGS. 6A-6B, 10A-10B) disposed proximal to the storage position, and an end-of-injection position (not shown) disposed distal to the storage and actuation positions. In the end-of-injection position, the plunger rod 2 may press against the stop 107 against the distal end of the reservoir formed by the barrel 101.
[0039] The automatic injector further includes a needle cover 5 disposed within the base body 10B. The needle cover 5 has a distal end 50 designed to be pressed against an injection site, such as a user's skin, a radial tab 52 for engaging a first slot 70 of the cam 7, and a proximal pressing surface 51 for abutting against the locking portion 3, as described in more detail below. The contact between the needle cover 5 and the locking portion 3 may be direct, i.e., without any intervening components. The proximal pressing surface 51 may extend circumferentially, with the upper surface of the tab 52 defining a radial portion of the pressing surface 51 to ensure abutment between the needle cover 5 and the locking portion 3. The needle cover 5 is axially movable along the longitudinal axis A relative to the housing 10 between a first extended position (pre-use position, Figures 5A-5B, 9A-9B) in which the needle cover 5 at least partially or completely shields the injection needle 103, a retracted position (Figures 6A-6B, 10A-10B) in which the needle cover 5 activates the automatic injector 1 and thus primes the injector, and a second extended position (safety position, not shown) in which the needle cover 5 moves back in the distal direction to safely shield the injection needle 103. Movement of the needle cover 5 from the first extended position to the retracted position is caused by the user pressing the distal end 50 of the needle cover 5 against the injection site, and movement of the needle cover 5 from the retracted position to the safe position is caused by the safety spring 8 pushing the needle cover 5 back in the distal direction when the user removes the injection needle 103 from the injection site.
[0040] As shown in FIG. 2 , the automatic injector 1 may include a cam 7. The cam 7 is in the form of a cylindrical ring having a first slot 70 and a second slot 71. The first slot 70 has an angled 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 cover 5, which is located at the first end 704 when the needle cover 5 is in the first extended position, at the second and third ends 705 and 706 when the needle cover 5 is in the retracted position, and near or at the fourth end 707 when the needle cover 5 is in the safe position. The second slot 71 includes an axial portion 710 that includes a proximal shoulder 711 and an angled portion 712 that extends from the proximal shoulder 711. The second slot 71 is engaged by the ring 108, which extends into the axial portion 710 when the needle cover 5 is in the first extended position. The cam 7 is pivotally mounted inside the housing 10. Rotation of the cam 7 is first caused by the radial tab 52 sliding against the angled portion 701 when the needle cover 5 moves from the first extended position to the retracted position, and then caused by the ring 108 sliding against the angled portion 712 when the ring 108 is pushed distally together with the medical container 100 by the injection spring 6. This second rotation of the cam 7 causes the radial tab 52 to move from the second end 705 to the third end 706, allowing the radial tab 52 to slide inside the axial portion 703 as the needle cover 5 moves from the retracted position to the safe position.
[0041] 2 and 4A-4B, the power injector 1 includes a locking portion 3. The locking portion 3 is disposed inside the top body 10A for distally blocking the plunger rod 2 in a storage position prior to actuation of the power injector 1. The locking portion 3 may be in the form of a tubular sleeve. The locking portion 3 may have a cylindrical transverse wall 30 having an inner surface 300 and an outer surface 301. The inner surface 300 defines an internal cavity 302 for receiving the plunger rod 2 and a biasing means. The internal cavity 302 has a proximal end 303 which may define a proximal opening 304 to allow insertion of the plunger rod 2 and the biasing means inside the locking portion 3, and an opposite distal end 305 which may define a distal opening 306 to allow extension of the plunger rod 2 outside the locking portion 3 as the plunger rod 2 moves from the actuation position to the ejection end position. The first block member 31 may extend at a distal end 305 of the internal cavity 302 .
[0042] The locking portion 3 is disposed inside the retaining portion 4 and is axially movable together with the plunger rod 2 relative to the retaining portion 4 between a storage position (FIGS. 5A-5B) in which the locking portion 3 prevents movement of the plunger rod 2 to the ejection end position, and an actuated position (FIGS. 6A-6B) in which the locking portion 3 is disposed proximal to the storage position and no longer prevents movement of the plunger rod 2 to the ejection end position. In the actuated position of the locking portion 3 and the plunger rod 2, the biasing means may be fully compressed.
[0043] The locking portion 3 includes a first blocking member 31 that is radially deformable between a blocking position in which it axially abuts against the distal abutment surface 20 of the plunger rod 2 to prevent distal movement of the plunger rod 2, and a release position in which the first blocking member 31 moves away from the distal abutment surface 20 of the plunger rod 2 to allow distal movement toward the end of injection position. The top body 10A includes a retaining portion 4, FIG. 5A , that includes a lateral abutment surface 40 for maintaining the first blocking member 31 of the locking portion 3 in the blocking position.
[0044] 4A-4B, the first blocking member 31 is in the form of a radially inward protrusion that projects from the inner surface 300 of the locking portion 3, more particularly from the inner surface 11 of the flexible leg 31 of the locking portion 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 prior to actuation of the automatic injector 1. The proximal abutment surface 310 may be sloped. The distal abutment surface 20 of the plunger rod 2 may also be sloped, and preferably, the distal abutment surface 20 of the plunger rod 2 and the abutment surface of the first blocking member 31 have complementary shapes, such as a frustum shape. This facilitates movement of the first blocking member 31 from the blocking position to the unlocked position.
[0045] The locking portion 3 may include two pairs of axial slots 312, each pair defining a flexible leg 311 from which a first blocking member 31 projects. The first blocking member 31 may be disposed at a distal end 316 of the flexible leg 311. The axial slots 312 have a closed proximal end 313 and an open distal end 314, which facilitates deformation of the flexible leg 311 between the blocking position and the unlocked position. The flexible leg 311 has a fixed proximal end 317.
[0046] It is envisaged that the released position of the first blocking member 31 may correspond to the deformed position of the flexible legs 311, and the blocked position of the first blocking member 31 may correspond to the rest position of the flexible legs 311. Thus, the movement of the first blocking member 31 from the blocked position to the released position is due to the distal pressure of the biasing means pressing the distal abutment surface 20 of the plunger rod 2 against the first blocking member 31. In another embodiment, the released position of the first blocking member 31 may correspond to the rest position of the flexible legs 311, and the blocked position of the first blocking member 31 may correspond to the deformed position of the flexible legs 311. In this case, the movement of the first blocking member 31 from the blocked position to the released position may be due to the elastic legs automatically returning to their natural rest position.
[0047] 4A-4B, the locking portion 3 may include a drive leg 32 for abutting against a proximal pressing surface 51 of the needle cover 5 when the needle cover 5 moves from the first extended position to the retracted position. The drive leg 32 thus includes a distal abutment surface 320 that receives a proximal pressing force from the needle cover 5. The distal abutment surface 320 may be the most distal surface of the locking portion 3. The drive leg 32 may be radially offset relative to the flexible leg 311. The locking portion 3 may thus include an outwardly extending radial arm 321 that connects the drive leg 32 to a lateral wall of the locking portion 3. The outwardly extending radial arm 321 may define a proximal stop 322 that may abut against the retaining portion 4 when the locking portion 3 is in the activated position. In the storage position of the locking part 3 and the first extended position of the needle cover 5 , an axial gap may exist between the proximal pressing surface 51 of the needle cover 5 and the drive leg 32 of the locking part 3 .
[0048] 5A, the locking portion 3 has an external abutment surface 315 radially opposite the first blocking member 31, configured to abut against the lateral abutment surface 40 of the retainer 4 when the locking portion 3 is in the storage position. This abutment between the external abutment surface 315 of the flexible leg 311 and the lateral abutment surface 40 of the retainer 4 maintains the first blocking member 31 in the blocking position. Referring to FIG. 9A, the external abutment surface 315 may be defined by a radially outward protrusion. The radially outward protrusion may define a guide proximal surface 42, which may be angled with respect to the longitudinal axis A to facilitate proximal insertion of the locking portion 3 inside the retainer 4.
[0049] The distal end 316 of the flexible leg 311 may include a chamfer 318 to facilitate passage of the first blocking member 31 from the blocking position to the release position.
[0050] 4A-4B, 5A-5B, and 6A-6B, the locking portion 3 includes a second blocking member 33 configured to distally block the locking portion 3 in the storage position. The second blocking member 33 may be disposed 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 activated position of the locking portion 3. The second blocking member 33 includes a distal stop 330 configured to abut against the proximal shoulder 41 (FIG. 5A) of the retainer 4 when the locking portion 3 is in the storage position.
[0051] As shown in FIGS. 4A-4B , the outer surfaces of the lateral walls of the locking portion 3 may define cylindrical outer surfaces forming guide portions 307 configured to guide the axial movement of the locking portion 3 inside the holding portion 4 between the storage position and the actuated position. The guide portions 307 are configured to slide relative to the holding portion 4. In the embodiment of FIGS. 4A-4B , the guide portions 307 are configured to allow the locking portion 3 to rotate inside the holding portion 4 about the longitudinal axis A. For example, the guide portions 307 may be devoid of any protrusions, which allows the locking portion 3 to be translated and then rotated inside the holding portion 4 for assembly.
[0052] 3, 5A-5B, and 6A-6B show the retainer 4. The retainer 4 may be in the form of a tubular sleeve extending axially inside the housing 10. The retainer 4 has a cylindrical transverse wall 43 defining an outer surface 430 and an inner surface 431. The outer surface 430 may be connected to the transverse wall 13 of the housing 10 by one or more reinforcing members 15. The reinforcing members 15 may be axially extending walls running along the inner surface 16 of the housing 10 and the outer surface of the retainer 4. The reinforcing members 15 may be regularly distributed around the longitudinal axis A or may extend in an imaginary longitudinal plane that includes the longitudinal axis A. For example, the automatic injector 1 has four reinforcing members 15, although the number and shape of the reinforcing members 15 may vary.
[0053] The inner surface 431 of the holder 4 defines an internal cavity 432 having 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 axial insertion of the locking portion 3, and / or the plunger rod 2 and biasing means, inside the holder 4. The open distal end 433 is also configured to allow extension of the plunger rod 2 outward from the holder 4 when the automatic injector 1 is actuated, i.e., when the plunger rod 2 moves from the actuated position to the end-of-injection position under the distal pressure exerted by the biasing means.
[0054] The internal cavity of the retainer 4 includes two cylindrical central surfaces 435 configured to guide the axial movement, and optionally, rotation, of the locking portion 3 within the retainer 4. The cylindrical central surfaces 435 suitably engage with the mounting portion of the locking portion 3, and they may have complementary shapes. In the illustrated embodiment, the retainer 4 includes two diametrically opposed central surfaces 435. The diameter between the two central surfaces 435 may be smaller than the diameter of the remainder of the internal cavity of the retainer 4, with the largest diameter configured to allow movement of the locking portion 3 from the stored position to the released position within the retainer 4. As seen in FIGS. 5A and 6A , the internal cavity of the retainer 4 provides space to allow outward deformation of the flexible legs 311 of the locking portion 3 from the blocked position to the released position.
[0055] 5A and 6A, the retaining portion 4 includes a lateral abutment surface 40 for radially abutting against the first blocking member 31, more specifically, against the outer abutment surface 315 of the locking portion 3, such that the first blocking member 31 is blocked in the blocking position as long as the locking portion 3 is in the storage position. The lateral abutment surface 40 may be defined by a radially inward protrusion 45 protruding from the inner surface 431 of the retaining portion 4. The radially inward protrusion 45 may be located at the distal end 434 of the retaining portion 4. When the locking portion 3 is moved to the activated position, the lateral abutment surface 40 of the retaining portion 4 no longer abuts against the first blocking member 31, allowing the first blocking member 31 of the locking portion 3 to flex outward to the released position.
[0056] The retaining portion 4 further includes a proximal shoulder 41 for axially abutting against the second blocking member 33 of the locking portion 3. The proximal shoulder 41 may be defined by a proximal side of a radially inward projection 45. In the stored position, the second blocking member 33 of the locking portion 3 axially abuts against the proximal shoulder 41. In the activated position, the second blocking member 33 of the locking portion 3 may be axially spaced from the proximal shoulder 41.
[0057] 3-6B, assembly of the locking part 3 inside the retaining part 4 is achieved by axially inserting the locking part 3 inside the retaining part 4, circumferentially shifting the second blocking member 33 over the radially inward projection 45 of the retaining part 4 so that the second blocking member 33 of the locking part 3 may pass proximally beyond the radially inward projection 45 of the retaining part 4, and then rotating the locking part 3 inside the retaining part 4 so that the second blocking member 33 axially faces the radially inward projection 45. As a result, the second blocking member 33 can abut against the proximal shoulder 41 of the retaining part 4, blocking the locking part in the storage position.
[0058] 3, the retainer 4 may include one or more axial notches 46 for receiving the drive legs 32 of the locking part 3. The axial notches 46 may have an open distal end 460 and a closed proximal end 461 that bounds a distal stop 462 that may be configured to abut against a proximal stop of the drive legs 32 when the locking part 3 is moved proximally. In either case, the axial clearance between the proximal stop of the drive legs 32 of the locking part 3 in the stored position and the distal stop 462 of the notch 46 is equal to or greater than the axial distance the locking part 3 must travel from the stored position to the activated position.
[0059] In the illustrated embodiment, the retainer 4 and the housing 10 are made from a single piece. Alternatively, the retainer 4 and the housing 10 may be two different parts, and the proximal end 433 of the retainer 4 may be secured to the housing 10 by any suitable means, such as, for example, a snap fit, a friction fit, or adhesive.
[0060] As seen in FIG. 3 , the housing 10 may have a containment wall 17 configured to laterally retain the proximal end 60 of the biasing means. The containment wall 17 may be in the form of an annular rib projecting distally from the transverse wall 14 of the housing 10. Preferably, the containment wall 17 and the transverse wall 14 of the housing 10 are made of a single piece. The containment wall 17 may define a distal stop 18 for abutting against the locking portion 3 when the locking portion 3 is moved proximally. In either case, the axial clearance between the proximal end 303 of the locking portion 3 in the stored position and the containment wall 17 or the transverse wall 14 is equal to or greater than the axial distance the locking portion 3 must travel from the stored position to the activated position.
[0061] Figures 7, 8A-8B, 9A-9B, and 10A-10B show another embodiment. As best shown in Figure 8A or 8B, the second blocking member 33 of the locking portion 3 may here be in the form of an axially extending tab instead of a circumferential rib. Moreover, the tab may be located in the proximal portion, i.e., the proximal half, of the locking portion 3. The second blocking member 33 (tab) includes a distal stop 330 configured to abut against the proximal shoulder 41 of the retaining portion 4 when the locking portion 3 is in the storage position (Figures 5A-5B, 9A-9B). The tab may include a first end 331 fixed to the outer surface 301 of the locking portion 3 and a second end 332 that may be free and define the distal stop 330. The first end 331 may be proximal, and the second end 332 may be distal. The tab may include an angled portion 333 extending from the first end 331 and which may be angled with respect to the longitudinal axis A, and an axial portion 334 extending from the angled portion 333 to the second end 332 parallel to the longitudinal axis A. The second blocking member 33 (tab) may be resiliently deformable between a retracted position (not shown) in which the tab flexes radially inward to allow proximal insertion of the locking portion 3 inside the retainer 4, and an extended position ( FIGS. 8A-8B , 9B , 10B ) in which the tab extends radially outward from the retracted position such that the distal stop 330 of the tab axially faces the proximal shoulder 41 of the retainer 4 and can abut against the proximal shoulder 41 when the locking portion 3 is in the retracted position. The lateral wall of the locking portion 3 may include a notch 335 that provides space for deformation of the second blocking member 33 in the storage position.
[0062] 8A-8B, the guide portion 307 of the locking portion 3 may include anti-rotation means for blocking rotation of the locking portion 3 relative to the retaining portion 4. Therefore, the first blocking member 31 cannot be rotated out of position relative to the retaining portion 4. Preferably, the anti-rotation means may be configured to rotatably position the locking portion 3 relative to the retaining portion 4 prior to assembly, i.e., align the first blocking member 31 of the locking portion 3 with the lateral abutment surface 40 of the retaining portion 4 and align the second blocking member 33 of the locking portion 3 with the proximal shoulder 41 of the retaining portion 4. The anti-rotation means may be in the form of axially extending ribs 308 projecting from the outer surfaces of the lateral walls of the locking portion 3. The axially extending ribs 308 define orthogonal stops 309 that abut against the retaining portion 4, more specifically, against corresponding abutment surfaces on either side of the central surface 435, to block rotation of the locking portion 3 relative to the retaining portion 4.
[0063] 7, 9B, and 10B, the proximal shoulder 41 of the retainer 4 is located in the proximal portion, or proximal half, of the retainer 4. In this case, the proximal side of the radially inward projection 45 of the retainer 4 may define an inclined surface 463 that is inclined with respect to the longitudinal axis A.
[0064] Assembly of the locking part 3 inside the holding part 4 is now achieved solely by movement of the locking part 3 inside the holding part 4. The second blocking members 33 are biased into a retracted position by abutment against the end stops 462 of the angled parts, and then slide against the central surfaces 435 of the holding part 4 until they reach the larger diameter portion 44 of the internal cavity, which diameter is larger than the diameter between the central surfaces 435 of the holding part 4. The larger diameter portion 44 of the internal cavity is separated from the central surfaces 435 by a proximal shoulder 41.
[0065] 2, 5A-5B, or 9A-9B, the plunger rod 2 is disposed within the locking member 3, more specifically, within the biasing means. The plunger rod 2 includes a distal end 22 for forcing the stop 107 into the barrel 101 of the medical container 100 and an opposite proximal end 23 that is spaced from the transverse wall 14 of the housing 10 when the plunger rod 2 is in the storage position. In the actuated position, the proximal end 23 may or may not abut against the transverse wall 14. The axial clearance 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 the plunger rod 2 must travel from the storage position to the actuated position. The distal abutment surface 20 of the plunger rod 2 is defined by the distal side of a radial flange 21. The radial flange 21 preferably extends 360° around the plunger rod 2. The distal abutment surface 20 may be inclined with respect to the longitudinal axis A. The distal abutment surface 20 may therefore deflect the first blocking member 31 under the action of the biasing means, which can therefore move from the blocking position to the release position as soon as the locking part 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 holding part 4. The opposite proximal side of the radial flange 21 may serve as a support for the distal end of the biasing means.
[0066] 11A-11B, the biasing means may be disposed inside the plunger rod 2 instead of extending around it. The plunger rod 2 is in the form of a tubular sleeve defining an internal cavity 25 for receiving the biasing means. The internal cavity 25 may define an open proximal end 23 that allows insertion of the biasing means 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 configured to receive the first block member 31 of the locking portion 3. The distal abutment surface 20 may be formed by the top side of the opening 24.
[0067] The operation of the automatic injector 1 is described below.
[0068] Prior to actuation of the automatic injector 1, the needle cover 5 is in the first extended position, the plunger rod 2 and locking portion 3 are in the storage position, the injection spring 6 is partially compressed, and the first blocking member 31 of the locking portion 3 is in a blocking position and cannot move to the release position due to its abutment against the lateral abutment surface 40 of the retaining portion 4. Additionally, the injection spring 6 maintains the locking portion 3 in the storage position, forcing the second blocking member 33 against the proximal shoulder 41. The biasing means resists inadvertent proximal movement of the locking portion 3 due to a drop test or accidental dropping. The plunger rod 2 is prevented from moving distally by the locking portion 3 (FIGS. 5A-5B and 9A-9B). Actuation of the automatic injector 1 is prevented.
[0069] The user must first pull the cap off the bottom body 10B, which involves removing the needle shield 104. During cap removal, the ring may abut against the proximal shoulder 41 of the cam 7, stopping the distal movement of the medical container 100.
[0070] The user then places the automatic injector 1 at the injection site. The distal end of the needle cover 5 rests against the injection site. As the user presses the automatic injector 1 against the injection site, the needle cover 5 moves from the first, extended position to the retracted position. This proximal movement of the needle cover 5 causes the radial tab 52 to slide against the cam 7. This causes the cam 7 to rotate, causing the ring to move away from the proximal shoulder 41 and now engage the axial portion. When the needle cover 5 reaches the retracted position, the radial tab 52 is at the second end of the first slot 70.
[0071] The proximal movement of the needle cover 5 toward the retracted position also presses the proximal pressure surface 51 of the needle cover 5 against (the drive leg 32 of) the locking part 3, thereby causing the locking part 3 together with the plunger rod 2 to be pressed from the storage position to the actuated position against the action of the injection spring 6. The first blocking member 31 therefore moves proximally and no longer abuts against the lateral abutment surface 40 of the holding part 4 (FIGS. 6A, 10A). The flexible legs 311 are now free to deflect radially outward. Due to the distal force exerted on the plunger rod 2 by the injection spring 6 and due to the contact between the plunger rod 2 and the first blocking member 31, the flexible legs 311 deflect outward. Thus, the first blocking member 31 moves to the release position, i.e., is moved away from the distal abutment surface 20 of the plunger rod 2, which can move toward the ejection end position under the action of the injection spring 6.
[0072] The plunger rod 2, coupled to the stop 107, first pushes the medical container 100 distally so that the injection needle 103 reaches the injection site. This movement causes the ring to slide against the angled portion of the second slot 71, further rotating the cam 7. The radial tab 52 reaches the third end of the first slot 70, and the needle cover 5 now has the ability to move distally toward the safety position. The plunger rod 2 then pushes against the stop 107 inside the barrel 101, expelling the medical product. When the stop 107 finally abuts against the distal end of the reservoir defined by the barrel 101, the injection is complete. An indicator, such as a visual, tactile, or audible indicator, may notify the user that the injection is complete.
[0073] The user then moves the automatic injector 1 away from the injection site. The radial tab 52 slides along the axial portion as the needle cover 5 moves from the retracted position to the safe position under the action of the safety spring 8. A locking mechanism may lock the needle cover 5 in the safe position to prevent needle stick injuries.
[0074] From the above, it can be readily seen that the automatic injector 1 of the present invention allows for a reduction in the steps required to initiate an injection (the user does not need to press a button, and the locking portion 3 automatically slides into the activated position once the automatic injector 1 is pressed against the user's skin). The resistance of the biasing means prevents inadvertent activation, and the user is given continuous feedback (without hard points or sudden releases) that the activation process is being carried out, i.e., that the automatic injector 1 is at the point where it should be activated. It should be understood that the present invention is not limited to the embodiments described above and illustrated in the drawings, but rather, those skilled in the art will recognize that many variations and modifications can be made within the scope of the appended claims.
Claims
1. An automatic injector (1) for automatically injecting a product into an injection site, said automatic injector (1) comprising: A housing (10) configured to receive a medical container (100) having a barrel (101) extending along a longitudinal axis A and defining a reservoir for containing a medical product, the barrel (101) having a distal end provided with an injection needle (103) and an open proximal end (105) configured to receive a plunger rod (2) for pressing a stop (107) located inside the barrel (101); a needle cover (5) coupled to the housing (10), the needle cover (5) being axially movable relative to the housing (10) between a first extended position in which the needle cover (5) at least partially shields the infusion needle (103), a retracted position in which the needle cover (5) moves proximally relative to the housing (10), and a second extended position in which the needle cover (5) moves back distally to shield the infusion needle (103); a plunger rod (2) axially movable inside the housing (10) between a storage position, an actuation position disposed proximal to the storage position, and an end-of-injection position disposed distal to the storage position and the actuation position, the plunger rod (2) being configured to press against the stop (107) when moving from the actuation position to the end-of-injection position in order to expel the medical product; a biasing means for biasing the plunger rod (2) in a distal direction toward the end-of-injection position; a locking portion (3) for distally blocking the plunger rod (2) in the storage position prior to actuation of the automatic injector (1), the locking portion (3) including a first blocking member (31) radially movable between a blocking position in which the first blocking member (31) axially abuts against a distal abutment surface (20) of the plunger rod (2) to prevent distal movement of the plunger rod (2) relative to the locking portion (3), and a release position in which the first blocking member (31) moves away from the distal abutment surface (20) of the plunger rod (2) to allow distal movement of the plunger rod (2) relative to the locking portion (3); a retaining portion (4) fixed to the housing (10) for maintaining the first blocking member (31) of the locking portion (3) in the blocking position, the retaining portion (4) including a lateral abutment surface (40) for radially abutting against the locking portion (3) so that the first blocking member (31) of the locking portion (3) is blocked in the blocking position, and the retaining portion (4) including a proximal shoulder (41) for axially abutting against the second blocking member (33) of the locking portion (3); Equipped with The locking portion (3) has a storage position in which the locking portion (3) abuts radially against the lateral abutment surface (40) of the retaining portion (4) so that the first blocking member (31) is blocked in the blocking position, and the second blocking member (33) of the locking portion (3) abuts axially against the proximal shoulder (41) of the retaining portion (4) so that the retaining portion (4) blocks the locking portion (3) distally in the storage position, and the locking portion (3) is disposed proximally with respect to the storage position, and the locking portion (3) is disposed proximally with respect to the storage position. and an actuated position, wherein the locking portion (3) is spaced from the lateral abutment surface (40) of the holding portion (4) so that the first blocking member (31) of the locking portion (3) can move from the blocked position to the released position, and movement of the locking portion (3) from the stored position to the actuated position is caused by movement of the needle cover (5) from the first extended position to the retracted position.
2. 10. The automatic injector (1) according to claim 9, wherein the first block member (31) defines a proximal abutment surface (310) for axial abutment against the distal abutment surface (20) of the plunger rod (2), and the proximal abutment surface (310) of the first block member (31) and / or the distal abutment surface (20) of the plunger rod (2) are inclined.
3. 10. An automatic injector (1) according to any preceding claim, wherein the first blocking member (31) is arranged on an inner surface of an axially extending flexible leg (311) of the locking part (3), the outer surface of which defines an external abutment surface (315) configured to abut against the lateral abutment surface (40) of the holding part (4) when the locking part (3) is in the storage position.
4. 10. The automatic injector (1) according to claim 9, wherein the first block member (31) is arranged at the distal end of the flexible leg (311), the flexible leg (311) being bounded between two axial slots (312).
5. 5. The automatic injector (1) according to claim 3 or 4, wherein the second blocking member (33) is arranged on the outer surface of the flexible leg (311) of the locking portion (3).
6. 10. The automatic injector (1) according to any of the preceding claims, wherein the locking portion (3) comprises a drive leg (32) for receiving a proximal push of the needle cover (5) as the needle cover (5) moves from the first extended position to the retracted position.
7. 10. An automatic injector (1) according to any preceding claim, wherein the locking portion (3) has a cylindrical guide portion (307) and the holding portion (4) has one or more cylindrical central surfaces (435) configured to guide the axial movement of the locking portion (3) inside the holding portion (4) between the storage position and the actuated position.
8. 10. The automatic injector (1) according to the preceding claims, wherein the guide portion (307) of the locking part (3) comprises anti-rotation means for blocking rotation of the locking part (3) relative to the holding part (4).
9. 9. The automatic injector (1) of claim 7 or 8, wherein the proximal shoulder (41) is disposed proximally relative to one or more central surfaces (435).
10. 10. An automatic injector (1) according to any preceding claim, wherein the lateral abutment surface (40) of the holding portion (4) is defined by a radially inward protrusion (45) and has a larger diameter portion (44) proximal to the radially inward protrusion (45) and configured to receive the first blocking member (31) of the locking portion (3) when the first blocking member (31) is moved to the release position.
11. 10. The automatic injector (1) according to the preceding claim, wherein the proximal shoulder (41) of the holding portion (4) is located proximal to the radially inward projection (45) of the holding portion (4).
12. 10. The automatic injector (1) according to any of the preceding claims, wherein the second blocking member (33) is an elastically deformable tab.
13. 10. An automatic injector (1) according to any preceding claim, wherein the housing (10) comprises a containment wall (17) configured to laterally retain the proximal end (60) of the biasing means.
14. 10. An automatic injector (1) according to any of the preceding claims, wherein the holding part (4) and the housing (10) are formed in a single piece.
15. 10. An automatic injector (1) according to any preceding claim, wherein movement of the locking part (3) from the stored position to the activated position is opposed solely by the biasing means.