The present disclosure relates to an autoinjector, the autoinjector comprises a housing, a needle guard mounted axially moveable in the housing for movement between a storage state, a dispensing state and a lock-out state in which states the needle guard adopts different axial positions relative to the housing, with the needle guard being configured to be axially moved in a proximal direction between the dispensing state and the lock-out state.
Autoinjectors are typically disposable devices configured to dispense medicament from a pre-filled syringe. Such devices are single-use and intended for administration by a patient (i.e. self-administration) or carer. At point of use, the user removes a protective cap from the proximal end of the autoinjector and positions the autoinjector at the injection site (typically the skin of the thigh or belly) and presses the autoinjector axially in a proximal direction, to achieve needle insertion of a needle of the pre-filled syringe into the skin and to initiate dispense.
It is an object of the present disclosure to make available an autoinjector formed from a very small number of low cost components and a very simple process, compared to the state of the art. It is a further object of the present disclosure to make available an as compact design as possible.
This object is satisfied by an autoinjector comprising the subject matter disclosed herein.
Such an autoinjector comprises a housing, a pre-filled syringe mounted in the housing and fixed relative to the housing, a needle guard mounted axially moveable in the housing for movement between a storage state, a dispensing state and a lock-out state in which states the needle guard adopts different axial positions relative to the housing, the needle guard comprising one or more clip arms, with the one or more clip arms being configured to engage a corresponding cut-out in the housing of the autoinjector in the storage state, and a drive chassis biased with respect to said housing, the drive chassis further being fixed with respect to the housing and a movement relative to the housing in a storage state of the autoinjector, the drive chassis being configured to axially move and act on said pre-filled syringe during dispensing, the drive chassis comprising one or more trigger arms, wherein the needle guard is configured to be axially moved in a distal direction between the storage state and the dispensing state and wherein the needle guard is configured to be axially moved in a proximal direction between the dispensing state and the lock-out state, wherein a respective one of the one or more trigger arms is configured to engage a respective one of one or more clip arms of the needle guard on moving the needle guard in the proximal direction between the dispensing state and the lock-out state.
The trigger arms can be configured to bias the clip arms towards the housing and thereby ensures that the clip arm engages the cut-out at the end of dispense to secure the needle guard relative to the housing after dispensing of the medicament has taken place.
In this way the drive chassis is configured to prevent the one or more clip arms from engaging the housing during release of the needle guard on transitioning from the dispensing state into the lock-out state of the autoinjector.
In this connection it should be noted that the needle guard can project further from the housing in the lock-out state than in the storage state. In this way a needle of the pre-filled syringe can be completely surrounded by the needle guard after use of the autoinjector leading to a better protection against accidental pricks.
Due to the disposable nature of single-use auto-injectors, it is considered advantageous to minimise autoinjector complexity, material usage, package size and assembly complexity in this way, as this all tends to reduce cost and environmental impact, this is achieved by the autoinjector presented herein and specifically providing the needle guard with a mechanism that can engage the housing and that can be disengaged from the housing in the various states of use.
Such an arrangement also leads to a reduction in the size of the device as the needle guard has several functions associated therewith thereby leading to a reduction of the number of parts needed and thus to a reduction of the volume of raw materials used.
Moreover, since fewer parts are used one can reduce the cost of manufacturing equipment and simplify the assembly process.
Smaller devices also lead to a reduction of the volume required in transport and storage, which can be particularly expensive when low temperatures are required. This also reduces the carbon footprint associated with such autoinjectors.
In this connection it should be noted that the drive chassis is a component that can be configured to move in a straight line within the housing in order to drive a medicament stored in a pre-filled syringe arranged within the housing out of the pre-filled syringe on activation of the autoinjector by entraining the plunger of the pre-filled syringe in a manner known per se.
Providing the needle guard with a plunger arm for activation of a release mechanism of the autoinjector enables a more compact design of the autoinjector. Moreover, such a plunger arm can reliably aid in triggering the autoinjector in an as simple as possible way.
Arranging the release mechanism between the housing and the drive chassis of the autoinjector also ensures an even compacter design of the autoinjector can be achieved.
In this connection it should further be noted that the axial position of the needle guard in the storage state and the lock-out state can be the same axial position or they can be different, axial positions.
The autoinjector can further comprise a lock-out spring arranged between the needle guard and the housing. Such a lock-out spring aids in moving the needle guard relative to the housing between the various states of use.
The needle guard can be configured to compress the lock-out spring on moving between the storage state and the dispensing state, and wherein the needle guard can be configured to be moved by a relaxation of the lock-out spring between the dispensing state and the locked out state.
Two or more clip arms can be provided, for example, each respective clip arm being arranged on opposite sides of the needle guard, with the lock-out spring being arranged between the two or more clip arms. In this way an as compact an assembly as possible can be formed.
The needle guard can comprise a projection projecting towards the housing, with the lock-out spring being arranged at the projection. The use of such a projection aids in the guidance of the lock-out spring. The projection can cooperate with an aperture in the housing such that a movement range of the lock-out spring is predefined within the autoinjector. Such a projection cooperating with an aperture also prevents a radial and/or transverse displacement of the lock-out spring, i.e. prevents buckling leading to a more reliable autoinjector.
An axial movement of the needle guard towards the drive chassis can release the fixing of the drive chassis with respect to the housing on activation of the autoinjector. The plunger arm can be reliably used as a trigger for the autoinjector.
The release mechanism can comprise the one or more trigger arms arranged at the drive chassis, the one or more trigger arms cooperating with a respective stop feature arranged at the housing, with the plunger arm being configured to deflect the one or more trigger arms on a distal axial movement of the needle guard. Such a release mechanism is simple to use and enables a compact design of the autoinjector.
The needle guard can be configured to cooperate with a cap via one or more snap-fit connections, optionally with each snap fit connection comprising a protruding edge cooperating with a corresponding snap-fit area and wherein an inner surface of the housing comprises one or more grooves in which one or more of said protruding edges can axially move relative to the housing on an axial movement of the needle guard. Such a cap protects an accidental activation of the autoinjector in the storage state and also prevents an accidental contact of the user with a needle thereof.
The one or more clip arms can each comprise a block at an end thereof, with the block being configured to engage a lock-out surface of the cut-out in the housing of the autoinjector in the lock-out state. Such a block, respectively a projection protrusion or the like, enables the clip arm to engage a part of the housing to clip the needle guard, i.e. hook the needle guard into place after a medicament has been dispensed.
The cut-out can be at least generally L-shaped respectively is L-shaped, with the lock-out surface being arranged at a short limb of the L-shaped cut-out. In this way a simple to manufacture engagement region of the clip arm can be formed.
The lock-out surface can be arranged at an angle to a long limb of the L-shaped cut-out. In this way a surface of the cut-out can be provided that only interacts with the clip arm in the lock-out state.
The short limb and the long limb of the L-shaped cut-out can be arranged at an angle to one another, with the angle being selected in the range of 10 to 120°; in particular of 20 to 80°. In this way one can ensure that the clip arm cannot readily be moved out of the lock-out state.
The one or more clip arms can extend in a proximal direction from the needle guard. This aids in forming an as compact an autoinjector as possible.
The one or more clip arms can extend in a proximal direction from the plunger arm of the needle guard. This ensures an even more compact design of the needle guard and thus of the autoinjector.
The needle guard can comprise a plunger arm for activation of a release mechanism of the autoinjector, and wherein the release mechanism can be arranged between the housing and the drive chassis of the autoinjector.
The needle guard can comprise a sleeve at a proximal end thereof. Such a sleeve can be configured to cover the needle respectively, the cannula of the autoinjector in the storage state and the lock-out state in order to protect a user from an unwanted prick.
The needle guard can be of at least generally T-shaped design respectively can be of T-shape, with the plunger arm then being arranged in parallel to an axial direction of the autoinjector from a proximal end to a distal end of said sleeve. Such a design enables a more compact assembly of the autoinjector.
The sleeve can comprise one or more elongate slots extending in parallel to an axial direction of the autoinjector from a proximal end to a distal end of said sleeve. Such slots can advantageously be used to guide the needle guard between the different states to ensure a smooth operation of the autoinjector.
The housing can comprise an inner body and an outer body, with the cut-out then being arranged at the inner body. Such a two-part housing is simpler to manufacture and hence reduces the cost of manufacture of such autoinjectors.
The disclosure will be described in the following with reference to the Figures and the submitted drawings by way of examples. In the drawings there is shown:
References made in the following regarding directions are made in the context of the drawing and can naturally vary if the viewing position is changed. Moreover, similar parts or parts having similar functions will be referred to in the following using the same feature and/or reference numeral.
The autoinjector 10 has a housing 12 with a syringe window 14 (see
A needle guard 18 (see e.g.
In this connection it should be noted that the terms proximal and distal refer to the position of the needle 34 relative to a patient with proximal meaning closest to a main mass of the body of a patient and distal meaning it is more distant from the main mass of the body of a patient.
A cap 70 is arranged at the proximal end 28 of the autoinjector 10 disposed opposite to a distal end 30 of the autoinjector 10. The cap 70 covers both the needle 34 and the needle guard 18 in the storage state of the autoinjector 10.
On engaging the release mechanism 40, the drive chassis 24 (see also
In this connection it should be noted that the plunger 26 can be a part separate from the dispensing limb 22 and can be pre-arranged within the pre-filled syringe and configured to be engaged by the dispensing limb 22.
In other designs of the autoinjector 10, the plunger 26 can be a part of the dispensing limb 22.
In the drawings shown above, the status indicator window 20 on the side of autoinjector 10 shows a device status in clear, binary form, which is likely to be very useful particularly to naïve users. Before (and possibly during) dispense, the colour displayed through the window is printed on the drive chassis 24 (see also
Moreover, before dispensing, the dispensable fluid volume of the medicament M is clearly visible through the syringe window 14 that is formed as a large wrap-around window in the housing 12. The geometry of this window 14 is intended to maximise the viewing angle for the user.
The progress of the dispensing can also be viewed through the window 20 as a movement of the plunger 26 and of the drive chassis 24 is visible through the syringe window 14.
At the end of the dispensing, the syringe window 14 is filled with the drive chassis 24 and the plunger 26 to provide additional visual indication that the autoinjector 10 has been used. This means that two forms of different visual indication of the end of dose are present. The part of the drive chassis 24 visible through the syringe window 14 could be provided with a surface decoration or marking, e.g. printed in a different colour to provide further visual communication of the end of the dose.
The trigger limb 32 and the dispensing limb 22 are arranged in an at least generally U-shaped manner respectively in a U-shaped manner and are connected to one another at a distal end 38 of the drive chassis 24 via a web 42, i.e. axially offset from one another in the transverse direction T with a length of the trigger limb 32 being longer than a length of the dispensing limb 22.
In this connection it should be noted that in other designs the dispensing limb 22 can also have the same length as the trigger limb 32 or even be longer than the trigger limb 32.
A plunger support 44 is arranged at an end of said dispensing limb 22 remote from said web 42. The plunger support 44 is configured to engage the plunger 26 that moves through the pre-filled syringe 16, i.e. the plunger support 44 is configured to act on the pre-filled syringe 16 of the autoinjector 10 via the plunger 26 that is arranged within the pre-filled syringe 16.
A trigger arm 36 is arranged to extend proximally from said trigger limb 32 in both a transvers direction T and a radial direction R relative to an axial direction A, with the axial direction A extending in parallel to the trigger limb 32. The trigger arm 36 is arranged extending from the trigger limb 32 in a direction remote from the distal end 38.
The trigger arm 36 is fixedly attached to the trigger limb 32 and moveable relative to the trigger limb 32.
The trigger arm 36 is connected to the trigger limb at a position corresponding to a length of the trigger limb 32 corresponding to 20 to 80% of a length of the trigger limb 32 from the distal end 38.
In this connection it should be noted that the drive chassis 24 is formed in one piece, i.e. the trigger limb 32, the dispensing limb 22, the plunger support 44 and the trigger arm 36 are integrally formed in one piece, preferably from one and the same material. e.g. in the same injection mold, or, if manufactured by additive manufacturing techniques, in one production cycle.
The drive chassis 24 can be installed in the autoinjector 10 shown in connection with
For this purpose, the drive chassis 24 can have first and second guiding aids 46, 48 cooperating with corresponding structures present within the housing 12. In the present example the first and second guiding aids 46, 48 are formed by first and second grooves 46′, 48′ that respectively extend in the axial direction A along the dispensing limb 22 respectively the trigger limb 32. The first and second grooves 46′, 48′ cooperate with lugs 164, 228 (see e.g.
Alternatively, the drive chassis 24 can comprise lugs cooperating with corresponding grooves in the housing 12 as the first and second guiding aids 46, 48.
Alternatively, the trigger limb 32 and the dispensing limb 22 can be shaped in such a way that they cooperate with guide structures present within the housing 12, by way of example, the trigger limb 32 and the dispensing limb 22 can have a round outer shape in a cross-section therethrough perpendicular to the axial direction A, with the round outer shapes of the trigger limb 32 and the dispensing limb 22 then being guided in complementary shaped parts of the housing 12.
In the storage state the trigger arm 36 is held at a stop feature 54 (see e.g.
In this connection it should be noted that the stop feature 54 is arranged at a height along the axial direction A of the housing 12 corresponding to a length of 45% of the length of the housing 12 from the distal end 30 of the autoinjector 10.
In this connection it should be noted that the stop feature 54 can be arranged at a height along the axial direction A of the housing 12 selected in the range of 30 to 70% of the length of the housing 12 from the distal end 30 of the autoinjector 10.
In this connection it should be noted that the trigger arm 36 is configured to move radially in the radial direction R and transversely in the transverse direction T with respect to the trigger limb 32.
The trigger limb 32 has an outer surface 49 comprising the first part outer surface 50 (hashed surface) and the second part outer surface 52 (black outer surface). The first and second part outer surfaces 50, 52 are present at a transverse side of the trigger limb 32, i.e. pointing in the transverse direction T. The first and second part outer surfaces 50, 52 are visible via the status indicator window 20 in different states of use of the autoinjector 10.
Specifically, as indicated in
A first limb of the U-shaped drive chassis 24 is formed by the dispensing limb 22 and a second limb of the U-shapes drive chassis 24 is formed by the trigger limb 32.
A distal end of the syringe window 14 is arranged at approximately the same height as a distal end of the status indicator window 20. The syringe window 14 and the status indicator window 20 are arranged in a part of the housing 12 where an inner body 80 and an outer body 82 (see
In this connection it should be noted that the first and second parts 50, 52 of the drive chassis 24 are not visible in the syringe window 14.
So that a user (not shown) can distinguish between the different states of use, i.e. between the first and second part outer surfaces 50, 52, the appearances of the first and second part outer surfaces 50, 52 differ from one another, i.e. these are different from one another.
In the present example the second part outer surface 52 comprises a marking printed thereon in the form of a hashed structure, other kinds of surface decorations and/or markings can be employed. The first part outer surface 50 is e.g. formed in the same colour as the remaining drive chassis 24, however, can also have some other colour comprise some form of surface marking and/or decoration or other form of visual indicator.
By way of example words such as “full and/or ready” and “empty and/or used” could printed on the first and second part outer surfaces 50, 52. Additionally and/or alternatively the first and second part outer surfaces 50, 52 can be coloured differently from one another. e.g. in red or green or the like.
The autoinjector 10 shown in
In the storage state of the autoinjector 10, a cap 70 is installed at the proximal end 28 of the autoinjector 10. On removal of the cap 70, the needle guard 18 of the autoinjector 10 becomes accessible.
The needle guard 18 is mounted axially moveable in the housing 12 for movement between the storage state, the dispensing state and the lock-out state. The needle guard 18 adopts different axial positions relative to the housing 12 in each one of the storage state, the dispensing state and the lock-out state.
As indicated in
The needle guard 18 can be moved automatically in the distal direction along the axial direction A as the patient moves the autoinjector 10 towards the injection point, as the contact with the patients' skin will automatically move the needle guard into the housing 12 of the autoinjector 10. For this purpose the needle guard 18 is configured to be axially moved in the distal direction between the storage state and the dispensing state.
On moving the needle guard from the storage state into the dispensing state the lock-out spring 76 is biased between the needle guard 18 and an inner body 80 of the housing 12.
Once a medicament M has been administered, i.e. dispensed from the autoinjector 10, the needle guard 18 is configured to be axially moved in the proximal direction between the dispensing state and the lock-out state on removing the autoinjector 10 from the injection site. This movement of the needle guard 18 is automatically brought about by a relaxation of the lock-out spring 76.
The housing 12 is a two-part housing formed of the inner body 80 and an outer body 82 that are fixed in position relative to one another and that are snap fit to one another via a connection 72.
As shown in
In this connection it should be noted that the connection 72 can also be brought about via a different kind of connection. For example, the nose 188 can be formed at the outer body 82 and project towards the inner body 80 and engage the window 190 then formed at the inner body 80, alternatively different forms of connector can be used to form the connection 72.
The trigger arm 36 is actuated on by the needle guard 18 of the autoinjector 10 on moving the autoinjector 10 from the storage state into the dispensing state of the autoinjector 10. As can be seen from a comparison of
The drive spring 74 is arranged within the housing 12 of the autoinjector 10. The drive spring 74 is specifically arranged between a distal housing wall 84 and the drive chassis 24. More specifically the drive spring 74 is arranged between the distal housing wall 84 of the outer body 82 and within the trigger limb 32 of the drive chassis 24. In order to fix a position of the drive spring 74 this can be arranged at a projection 86 projecting proximally from the distal housing wall 84 of the outer body 82.
The drive spring 74 is received within a passage 140 formed in the trigger limb 36 of the drive chassis 24. This means that the trigger limb 36 is configured to receive the drive spring 74. In the present example, the passage 140 has a cylindrical shape that is complementary to an outer shape of the drive spring 74.
As can be seen from a comparison of
The drive spring 74 also biases the trigger arm 36 in the storage state of the autoinjector 10 with respect to the housing 12 of the autoinjector 10 by urging this against the stop feature 54 by means of the inherent spring bias of the drive spring 74.
The drive spring 74 is further configured to drive the plunger support 44 of the drive chassis of the autoinjector 10 into the pre-filled syringe 16. This is due to the fact that the drive chassis 24 is linearly guided within the housing 12 and is permitted to move proximally once the trigger arm 36 is released from its engagement with the stop feature 54.
The needle guard 18 surrounds the needle 34 of the pre-filled syringe 16 in the storage state and in the lock-out state. Once the cap 70 is removed and the autoinjector 10 has been moved into the dispensing state, the needle guard 18 does not surround the needle 34 of the pre-filled syringe 16.
As indicated in
The lock-out spring 76 is biased between an end wall 88 of the needle guard 18 and a proximal end 92 of the inner body 80. The end wall 88 is arranged proximally with respect to the inner body 80 and the drive chassis 24.
Moreover, the needle guard 18 comprises a projection 90 projecting distally from the proximal end 28. The lock-out spring 76 is arranged at the projection 90, in particular, the projection 90 projects into the lock-out spring 76.
The needle guard 18 is configured to compress the lock-out spring 76 on moving between the storage state and the dispensing state. This is possible as the lock-out spring 76 abuts a proximal end 92 of the inner body 80 of the autoinjector 10 and the projection 90 is guided through an aperture 91 present in the inner body 80.
Following a use of the autoinjector 10 and removal of the autoinjector from an injection site, the needle guard 18 is configured to be moved by a relaxation of the lock-out spring 76 between the dispensing state and the lock-out state in a proximal direction.
In this connection it should be noted that the projection 90 could also be provided at the inner body 80 such that it projects towards the proximal end 28 of the needle guard 18. If this option is selected, then a length of the projection 90 has to be adapted such that the projection does not prevent a movement of the needle guard in the distal direction and/or such that it does not project beyond the needle guard 18 in the dispensing state so as to not come into contact with a patient's skin, e.g. if it cooperates with an aperture (not shown) of the needle guard 18.
In the storage state of the autoinjector 10, the needle guard 18 is arranged at a first axial position. In the dispensing state the needle guard 18 is arranged at a second axial position and in the lock-out state the needle guard 18 is arranged at a third axial position. The first, second and third axial positions respectively differ from one another, with the third axial position being more proximal than the first and second axial positions and the first axial position being more proximal than the second axial position with respect to the housing 12.
In this connection it should be noted that the third axial position can be the same or very similar to the first axial position in other designs of the autoinjector 10.
This means that an outer length of the autoinjector 10 with the cap 70 removed is longest in the lock-out state, shortest in the dispensing state and of medium length in the storage state.
In this connection it should be noted that each of the following components can be respectively integrally formed in one piece, preferably from one and the same material. e.g. in the same injection mold, namely the outer body 82, the inner body 80, the drive chassis 24, the needle guard 18, the cap 70, and/or the needle shield 78.
As shown in
A needle guard facing end 102 of the cap 70 comprises a needle shield holder 104 at an end of the cap 70 disposed opposite to the base 100. The needle shield holder 104 is configured to hold the removable needle shield 78 covering the needle of the pre-filled syringe 16 in the storage state of the autoinjector 10.
The inner wall 106 of the needle shield holder 104 further comprises two windows 112.
A respective one of the inwardly facing projections 108 is arranged at each of the windows 112.
Two recesses 114 are formed in the inner wall 106 of the needle shield holder 104 of the cap 70. The recesses are arranged between respective parts of the needle shield holder 104 having the windows 112.
The needle shield holder 104 projects distally from the base 100 of the cap 70 and is surrounded by an outer wall 116 of the cap 70. An inner surface 118 of the outer wall 116 of the cap 70 comprises several ribs 120.
As indicated in
The ribs 120 are configured to press radially inwardly, i.e. in the radial direction R, and transversely inwardly, i.e. in the transverse direction T, against the needle guard 18 in the storage state of the autoinjector 10.
As also shown in
As indicated in
The snap-fit connection 94 holds the cap 70 in place in the storage state of the autoinjector. The cap 70 is removably connected to the needle guard 18 and, on removal of the cap 70, the needle shield 78 is also removed from the autoinjector 10, as the projections 108 of the cap press on the syringe facing surface 110 of the removable needle shield 78 to entrain the removable needle shield in the proximal direction on removal of the cap 70.
In order to permit an as compact as possible design of the autoinjector 10, an inner surface 128 of the outer body 82 comprises a groove 130 in which one of said protruding edges 96 can axially move relative to the outer body 82 on an axial movement of the needle guard 18.
Similarly, an inner surface 132 of the inner body 80 comprises a further groove 134 in which a further one of said protruding edges 96 can axially move relative to the inner body 80 on an axial movement of the needle guard 18 relative to the housing 12.
The snap-fit projection 96 thereby forms detent features on the needle guard 18 that engage with corresponding features on the cap in order to provide a tight axial fit between the components following assembly.
A reverse arrangement of the detent features can also be possible, e.g. snap-fit areas can be present at the housing 12 and corresponding snap-fit projections could be present at the cap 70.
The proximal side of these detent features (snap-fit projections 96) on the needle guard is relatively steep, i.e. the proximal side of the snap-fit projections 96 is steeper than the distal side of the snap-fit projections 96 in the axial direction, so that once the cap 70 is removed, if the user attempts to re-attach it, the force to re-engage the detent features is high enough to cause the needle guard 18 to be moved distally until the detent features are hidden within the housing 12.
In this way, re-attachment of the detent features will not be possible (although the cap can be held in place by the engagement of the RNS 78 and the syringe glass). The distance by which the needle guard 18 is moved in order to hide the detent features is designed to be less than the distance required to trigger dispense, so that attempted re-attachment of the cap 70 in this way does not trigger dispense.
When the cap 70 is attached to the autoinjector 10. i.e. to the needle guard 18 via the snap-fit connection 94, the cap 70 prevents axial movement of the needle guard 18 when attached to the needle guard 18 in the storage state.
As further indicated in
It should be noted in this connection that the outer wall 136 of the housing is the outer wall 136 of the outer body 82 forming a part of the two-part housing 12.
Clip features in the form of the projections 108 on the cap 70 act on the distal surface of the rigid needle shield (RNS) 78 to grip onto it and remove it from the pre-filled syringe 16 when the cap 70 is pulled off by the user.
In this connection it should be noted that a ‘three plate tool’ construction can be used to mould the cap 70, including the clip features (projections 108) in a single component in a common injection mold (not shown) where state of the art devices typically construct similar caps from two or more separate components.
The projections 108 are supported by the needle guard 18 during removal of needle shield 78, helping to prevent them from splaying outwards and disengaging, as the needle shield holder 104 is biased radially inwardly by the needle guard 18.
These Figures illustrate a distal movement of the needle guard 18 into the housing 12 and how this then engages the release mechanism 40 comprising the trigger arm 36 and the stop feature 54 before the drive chassis 24 is moved proximally in order to administer the medication M stored in the pre-filled syringe 16.
The needle guard 18 comprises a plunger arm 142 as part of the release mechanism 40 of the autoinjector 10. The plunger arm 142 extends distally from the front end 122 of the needle guard 18.
As can be seen the relative position of the plunger arm 142 relative to the housing 12 varies and a distance the needle guard 18 projects beyond the housing 12 at the proximal end 28 reduces between
In this connection it should be noted that the opening 138 of the housing 12 is indicated as a through-going opening, i.e. it is open both at an outer wall of the housing 12 as well as an inner wall of the housing 12. It should however be noted that it can also be formed as a recess in the inner wall of the housing 12 such that it does not go through the wall of the housing 12.
The drive chassis 24 is mounted in said housing 12, the drive chassis 24 is biased with respect to said housing 12 via the drive spring 74. The drive chassis 24 is further fixed with respect to the housing 12 and a movement relative to the housing 12 in the storage state of the autoinjector 10 via the trigger arm 36 that is held at the opening 138.
In the storage state of the autoinjector 10, the drive spring 74 biases the trigger arm 36 in the axial direction A against the stop feature 54. The trigger arm 36 is present at the right hand side in the opening 138 (of the present Figure).
In order to activate the autoinjector 10 and to release the drive chassis 24 for its proximal movement, the autoinjector 10 comprises the release mechanism 40.
The release mechanism permits a relative movement between the needle guard 18 and the drive chassis 24. This relative movement is achieved by an axial movement of the needle guard 18 towards the drive chassis 24 which releases the fixing of the drive chassis 24 with respect to the housing 12 on activation of the autoinjector 10.
For this purpose the plunger arm 142 is configured to cooperate with the trigger arm 36 of the drive chassis 24 for activation of the release mechanism 40. On moving the plunger arm 142 in the distal direction the plunger arm 142 contacts and thereby deflects the trigger arm 36 in the transverse direction T as indicated by the arrow B and a comparison of the position of the trigger arm 36 relative to the opening 138 shown in
The plunger arm 142 of the needle guard 18 comprises a blocking rib 144. The blocking rib 144 is configured to block a radial movement of the trigger arm 36 when the plunger arm 142 contacts the trigger arm 36.
In this connection it should be noted that the blocking rib 144 is also configured to block a radial movement of the trigger arm 36 during the storage state prior to the plunger arm 142 contacting the trigger arm 36 due to an axial movement of the needle guard 18.
In order to engage the trigger arm 36, the plunger arm 142 comprises a cam 162. The cam 162 has an engagement surface 146 configured to engage the trigger arm 36. The engagement surface 146 projects from the cam 162 of the plunger arm 142 at a position adjacent to the blocking rib 144 in the transverse direction T such that it faces the trigger arm 36.
The trigger arm 36 comprises a web 148. The web 148 extends axially (proximally) below the projection 154 from the trigger arm 36 and provides a contact surface in the transverse direction T facing the cam 162 of the plunger arm 142 for engagement with the cam 142 following axial (distal) movement of the needle guard 18.
On distally moving the needle guard 18, the engagement surface 146 engages the web 148. This means that the web 148 and the engagement surface 146 are provided to further facilitate the contact between the trigger arm 36 and the plunger arm 142.
In a non-shown embodiment, the web 148 can comprise a deflection surface 150 inclined with respect to the trigger arm 36 relative to the axial direction A, i.e. a movement direction of the drive chassis 24.
In this connection it should be noted that the deflection surface 150 can be inclined with respect to the axial direction A at an angle selected in the range of 0 to 40°, especially in the range of 5 to 35° and most preferably in the range 10 to 30°.
The engagement surface 146 is also inclined with respect to a movement direction of the drive chassis 24, i.e. with respect to the axial direction A. The engagement surface 146 is inclined to gradually deflect said trigger arm 36 in the direction transverse to the axial direction A of movement of the needle guard 18 in order to shift the trigger arm 36 from the right hand side of the opening 138 of
In this connection it should be noted that the engagement surface 146 can be inclined with respect to the trigger arm 36 at an angle selected in the range of 5 to 50°, especially in the range of 7 to 30° and most preferably in the range 8 to 20°.
In this connection it should be noted that the engagement surface 146 and the web 148 are arranged to face one another in a cooperating manner.
When the engagement surface 146 contacts the web 148 respectively the deflection surface 150, the trigger arm 36 is configured to be moved, in particular disengaged, from said stop feature 54, through a deflection in the direction of the arrow B.
The opening 138 at which the stop feature 54 is arranged comprises a surface 152 that has a convex shape. The trigger arm 36 is configured to cooperate with said convex surface 152 of said stop feature 54.
For this purpose the trigger arm 36 comprises a projection 154 engaging the stop feature 54. The projection 154 is configured to cooperate with said opening 138 by engaging into this and by resting on said surface 152 of the stop feature 54 at least in the storage state of the autoinjector 10.
The web 148 is arranged at a surface of the trigger arm 36 different from a surface at which the projection 154 of the trigger arm 36 is arranged. The projection 154 is arranged to project radially from said trigger arm 36, whereas the web 148 is arranged to project transversely from said trigger arm 36.
As discussed in the foregoing, the stop feature 54 comprises the convex surface 152 formed by first and second planar surfaces 156, 158 inclined with respect to one another. The first and second planar surfaces 156, 158 adjoin one another at the apex 160 formed therebetween.
In this connection it should be noted that an angle of inclination between the first and second planar surfaces 156, 158 is selected in the range of 110 to 175°, preferably in the range of 120 to 1700 and especially in the range of 130 to 165°.
In this connection it should further be noted that an angle between the first planar surface 156 and the axial direction A is selected in the range of 0 to 50°, especially in the range of 1 to 30° and most preferably in the range of 2 to 20°.
In this connection it should further be noted that an angle between the second planar surface 158 and the axial direction A is selected in the range of −20 to 20°, especially in the range of −10 to 100 and most preferably in the range of −5 to 5°.
The apex 160 forms an overhauling angle the trigger arm 36 faces on activation of the autoinjector 10 in order to shift this from the storage state into the dispensing state.
In this connection it should be noted that the faces of the trigger arm can preferably be inclined and angled in such a way that the inclination and angle matches the angles and inclinations of the first and second planar surfaces 156, 158. In this way a contact area between the first and second planar surfaces 156, 158 can be maximised providing an improved attachment between the respective surfaces particularly in the storage state.
In the storage state the blocking rib 144 is configured to block radial movement of the trigger arm 36, since it forms a wall against which the trigger arm 36 abuts in the event that the trigger arm 36 is urged radially inwardly in a non-permitted manner, e.g. from the outside of the opening 138 when the plunger arm 142 contacts the trigger arm 36.
In this storage state the drive spring 74 urges the drive chassis 24 in the axial direction A and the drive chassis 24 is axially held in position at the opening 138 via the protrusion 154 of the trigger arm 36.
More specifically, the protrusion 154 is so to say held in the acute space formed by the first planar surface 156 of the stop feature in the opening, as to move the trigger arm 36, this not only has to be moved in the transverse direction T but also distally in the axial direction A.
Once the needle guard 18 is moved towards the drive chassis 24 on moving the autoinjector 10 from the storage state into the dispensing state, the plunger arm 142 via the engagement surface deflects the trigger arm 36, i.e. via the deflection surface 150 of the web 148, both distally in the axial direction A by lifting the web 148 distally in the axial direction A and pushing the web 148 transversely in the transverse direction T.
Once the projection 154 of the trigger arm 36 has passed the apex 160, the spring force of the drive spring 74 causes the drive spring 74 to relax and urge the drive chassis 24 proximally in the axial direction A and the trigger arm 36 out of engagement from the opening 138 as indicated e.g. in
Moreover, once the engagement surface 146 of the plunger arm has deflected the trigger arm 36 in the transverse direction T this can also be deflected radially inwardly in the radial direction R. As is shown in
Prior to dispense, the trigger arm 36 of the drive chassis 24 is biased into engagement with the axial stop feature 54 in the outer body 82 of the housing 12.
Under the action of the axial force from the drive spring 74 on the drive chassis 24, the trigger arm 36 is discouraged from moving either transversely or radially inwards by:
In this connection it should be noted that this geometry can require the drive chassis 24 to be slightly lifted and therefore the drive spring 74 to be slightly compressed in order to disengage the trigger arm 36. However, sufficient robustness (i.e. protection against accidental triggering) can be achieved purely by a combination of the load and frictional coefficient of the surfaces of the stop feature 54 and of the trigger arm 36 in contact. If the frictional coefficient is high enough, even a negatively inclined holding surface (opposite to that shown in the diagram) can be functional.
The blocking rib 144 on the needle guard 18 also prevent the trigger arm 36 from moving radially inwards. It would also be feasible to add further blocking rib features (not shown) to the needle guard to prevent transverse movement of the trigger arm 36. These transverse blocking rib features would be arranged such that, during the initial displacement of the needle guard 18 on actuation, they axially disengage from and release transverse movement of the trigger arm 36.
The angled engagement surface 146 of the cam 162 of the needle guard 18 contacts the trigger arm 36 and translates its projection 154 transversely over the apex 160 of the stop feature 54 in the outer body 82 of the housing 12.
Once the projection 154 of the trigger arm 36 is over the apex 160 of the stop feature 54, it engages with a steeper slope of the second planar surface 158 that, under the action of the drive spring 74, causes the trigger arm 36 to continue to deflect and eventually disengage the stop feature 54 also in the radial direction without further contact from the needle guard 18.
In an alternative embodiment, the cross-section profile of the trigger arm 36 tends to create a radial movement of the projection 154 (to enable disengagement) when the arm 36 is moved transversely.
Once fully disengaged, the drive chassis 24 advances towards the pre-filled syringe 16 to engage the plunger 26 and starts to dispense medicament M under the action of the drive spring 74.
The drive chassis 24 is likewise inserted into the inner body 80. The inner body 80 comprises the lug 164 cooperating with the second groove 48′ of the drive chassis 24 as the second guiding aid 48 that enables a linear guidance of the drive chassis 24 within the inner body 80 of the housing 12.
The needle guard 18 comprises a protrusion 166 cooperating with an elongate hole 168 present in the inner body 80, to ensure a linear guidance of the needle guard 18 relative to the inner body 80.
The needle guard 18 further comprises an anti-pull off feature 170. The anti-pull off feature 170 being configured to prevent a removal of the needle guard from the proximal end of the housing 12.
For this purpose the elongate hole 168 comprises a proximal stop 172 that prevents the protrusion 166 from being moved proximally beyond the stop 172 and hence the stop 172 acts as the anti-pull off feature 170 of the needle guard 18.
In this connection it should be noted that the elongate hole 168 is dimensioned such that it is complementary to the shape of the protrusion 166 and such that it defines a linear movement range of the needle guard 16 relative to the inner body 80.
This means that a width of the elongate hole 168 perpendicular to the axial direction A can be selected such that it is complementary to a width of the protrusion perpendicular to the axial direction A.
Moreover, a length of the elongate hole 168 between the proximal stop 172 and a distal stop 192 in parallel with the axial direction A can be selected to correspond to a movement range along the axial direction of the needle guard 18.
The inner body 80 further comprises a first cut-out 174. The first cut-out 174 being configured to cooperate with a clip arm 184 and a lock-out arm 186 of the needle guard 18.
Specifically, as shown in
The first and second portions 180 and 182 of the first cut-out respectively have a rectangular shape, directly adjoin one another and are offset along the axial direction A with respect to one another.
The inner body 80 further comprises a second cut-out 176 that is axially arranged adjacent to the first cut-out 174 and is separated from the first cut-out 174 by a bar 178. The second cut-out 176 is configured to cooperate with the lock out arm 186.
In this connection it should be noted that the second cut-out is configured to only cooperate with the lock-out arm 186 and thus not with the clip arm 184. This is made possible due to the offset between the first and second portions 180, 182.
In this connection it should further be noted that the lock-out arm comprises an engagement portion 220 that is configured to engage a corresponding cut-out 176.
In the embodiment shown the engagement portion 220 has a ramp 222 via which it can overcome the bar 178 on being moved proximally from the first cut-out 174 to the second cut-out 176 and a planar portion 224 that is configured to drop into the second cut-out 176 and then to act as an abutment that prevents a distal movement of the needle guard 18 out of the lock-out state beyond the bar 178.
As indicated the first cut-out 174 can be present at the same side of the inner body 80 as the elongate hole 168. The first cut-out 174 can also be present at a side different from the side at which the elongate hole 168 is arranged. It is further possible that two first cut-outs 174 and/or two elongate holes 168 are provided that are then arranged at oppositely disposed sides of the inner body 80 (see e.g.
As also indicated in
The function of the needle guard 18 before dispensing is as follows:
The needle guard spring, i.e. the lock-out spring 76 (that is biased against the inner body 80) applies a proximal force to the needle guard 18. The needle guard 18 is axially retained within the inner body 80 by its clip arm 184. The needle guard lock-out arm 186 is in clearance to the inner body to avoid long term creep affecting subsequent lock-out robustness.
As the needle guard 18 is pressed during dispense by the user, the clip arm 184 moves up within the first cut-out 174, more specifically within the first portion 180 of the first cut-out 174, in the inner body 80. Towards the end of the dispense stroke of the drive chassis 24 (but before an end of dose click (see
Once a user removes the needle 34 and thereby the needle guard 18 from the skin, the needle guard 18 extends linearly proximally under the action of the lock-out spring 76. Because the clip arm 184 is deflected radially inwards by the drive chassis 24, it does not engage with an inner body assembly stop feature 194 during this return travel. Instead, the needle guard 18 continues to extend until its lock-out arm 184 engages with the bar 178 of the inner body 80 in an extended position to lock the needle guard 18 from being able to move in the distal direction. The bar 178 separates the first cut-out 174 from the second cut-out and the lock-out arm 184 is moveable within the first cut-out 174 during use and prior to lock-out of the needle guard 18.
Moreover, the protrusion 166 prevents the needle guard 18 from being moved more proximally, in the lock-out state as it engages the proximal end of the elongate hole 168 acting as the anti-pull off feature 170.
The trigger limb 32 further comprises at least a first part 56 of an audible end of dose feedback member 58 in the shape of a click arm 56. The first part 56, i.e. the click arm 56, is formed by a nose 60, optionally having a generally triangular outer shape, formed at an end of a tongue 62, projecting from the trigger limb 32.
The tongue 62 projects from the trigger limb 32 in the region of a recess 64 formed in the outer surface 49 of the trigger limb 32. An opening 68 of the recess 64 faces in the radial direction R.
The inner body 80 of the housing 12 further comprises at least a second part 66 of the audible end of dose feedback member 58 (see e.g.
The second part 66 of the audible end of dose feedback member 58 comprises a distal surface 196 and a proximal surface 198 surrounding an inner body recess 206.
In this connection it should be noted that the positioning of the respective first and second parts 56, 66 of the audible feedback member 58 could be reversed, i.e. the recess 206 could be provided at the drive chassis 24, whereas the tongue 62 could be provided at the inner body 80. It should also be noted that each one of the drive chassis 24 and the inner body 80 could comprise a respective first and second part 56, 66 of the audible feedback member 58 which cooperate with a respective other one of the first and second part 56, 66 of the audible feedback member 58 provided at the other component, i.e. the inner body 80 has both a recess and a tongue each cooperating with a respective one of a tongue and a recess at the drive chassis 24.
On use of the autoinjector 10, the trigger limb 32 is moved by the drive spring 74 in the axial direction A during dispensing, the first part 56 of the audible end of dose feedback member 58 is then deflected in the transverse direction T towards the drive spring 74.
This is achieved as an inclined surface 200 of the end of dose feedback member 58 is deflected by a distal inner housing end 204 of the inner housing 80. This can be aided as the distal inner housing end 204 can be chamfered towards the distal wall 84 of the housing 12.
The audible end of dose feedback member 58 is configured to emit a sound once the material has been dispensed from the autoinjector, i.e. once a click surface 202 of the nose 60 attached to the latching tongue 62 engages the distal surface 196 of the inner body recess 206 by moving in the transverse direction T outwardly.
The positions of the first and second parts 56, 66 of the audible feedback member 58 are selected such that the audible click occurs once the plunger 26 reaches or is about to reach its final position in the pre-filled syringe 16.
Thereby the audible end of dose feedback member 58 is configured to emit a sound between the drive chassis 24 and the housing 12 once the material has been dispensed from the autoinjector 10.
Thus, towards the end of dose, the nose 60 of the drive chassis 24 engages with a ramp of the inner body 80, i.e. the chamfered distal inner housing end 204 which deflects the tongue 62 radially inwards. Near the end of travel, nose 60 drops through the inner housing recess 206 in the inner body 80, rapidly releasing its deformation and creating an audible click (either by virtue of contact with another component surface or purely acceleration in the air).
The windows 112 shown in
The recesses 114 shown in the
In this connection it should further be noted that the provision of the windows 112 at the needle shield holder 104 also provide a respective tooling lead-in surface that enables ejection of the cap 70 from the injection mold tool.
As indicated in the section shown in
An inner shape of the needle shield holder 104 is shaped complementary to an outer shape of the removable needle shield 78 to aid an as compact a design as possible of the cap 70 and to permit a reliable removal of the removable needle shield 78 on removing the cap 70 from the autoinjector 10.
Moreover, the opening 124 of said cap 70 is formed between the outer wall 116 of said cap 70 and the needle shield holder 104. The dimensions of the opening are selected in dependence on the dimensions of the part of the needle guard that is to be inserted into the opening in the storage state to the autoinjector 10.
The needle shield holder 104 projects distally from the base 100 of the cap 70 and is surrounded by the outer wall 116 of the cap 70. The inner surface 118 of the outer wall 116 of the cap 70 comprises several ribs 120. These ribs are configured to press against the front end 122 of the needle guard 18 when this is arranged within the opening 124.
As indicated in the section shown in
The inner wall 106 of the needle shield holder 104 further comprises the two windows 112, with a respective one of the inwardly facing projections 108 being arranged at each of the windows 112.
Two recesses 114 are formed in the inner wall 106 of the needle shield holder 104 of the cap 70. The recesses are arranged between respective parts of the needle shield holder 104 having the windows 112.
The snap-fit areas 98 of the cap 70 are provided at the inner surface 118 of the cap 70 and a first snap-fit area 208 is formed within some of the ribs 120 of the cap, whereas a second snap in area 210 is formed in a region of the cap 70 free of ribs 120.
The cap 70 is of single piece design and an end face in a proximal surface of the cap 70 at the base 100 does not comprise a hole.
In contrast to the embodiment shown in connection with the previous figures, the outer body 82 comprises two stop features 54 present at either side of the outer body 82 in the respective windows 40 as indicated in
Moreover, the projection 86 projecting from the distal wall 84 of the outer body 82 of the housing 12 is visible in
In this connection it should be noted that the drive chassis 24 is a component that can be configured to move in a straight line within the housing 12 in order to drive the medicament M stored in the pro-filled syringe 16 arranged within the housing 12 out of the pre-filled syringe 16 on activation of the autoinjector 10 by entraining the plunger 26 of the pre-filled syringe 26.
The inner body 80 is configured to cooperate with the outer body 82 of
Moreover, the needle guard 18 also comprises a single plunger arm 142 having two blocking ribs 144 and two cams shaped in the manner described in the foregoing. The blocking ribs 144 are configured to cooperate with the drive chassis 24 discussed in connection with
The section B:B of
The lip 216 comprises two tips 218, with each tip 218 being configured to engage a respective one of the clip arms 184 formed at the needle guard 18.
It should also be noted that the first and second guiding aids extend proximally from the web 42, with the second groove 48′ extending directly from the web 42 and the first groove 46′ begin offset from the web 42.
In the foregoing the mechanism elements of a disposable auto-injector 10 to dispense medicament M from the pre-filled syringe (PFS) 16 are described. The design disclosed permits state of the art features to be incorporated into a small physical package using a very small number of low cost components and a very simple process, compared to the state of the art.
The auto-injector device disclosed consists of an assembly surrounding a pre-filled syringe (PFS) 16 that contains medicament M. Typically, such devices are single-use and intended for administration by a patient (i.e. self-administration) or carer.
At point of use, the user removes the protective Cap 70 from the proximal end of the autoinjector 10, positions the autoinjector 10 at the injection site (typically the skin of the thigh or belly) and presses the autoinjector 10 axially in a proximal direction, to achieve needle insertion of the needle 34 into the skin and to initiate dispense.
Energy from a helical compression drive spring 74 is released to displace the plunger 26 within the PFS 16 and deliver the medicament m to the patient. An audible click notifies the patient that dispense has started. In this connection it should be noted that such an audible click can be generated when the trigger arm 36 cooperates with the stop feature 54 on triggering the release mechanism 40 on moving the autoinjector 10 from the storage state to the dispensing state. The progress of dispense can be monitored by the user as a change in position of the PFS plunger 26 and mechanism plunger within the large wrap-around ‘syringe window’ 14.
The user is notified when the dose is complete by an audible click emitted from the autoinjector 10 and a change in the colour displayed within a unique ‘status indicator window’ 20. The autoinjector 10 can then be removed from the injection site, allowing the sprung needle guard 18 to extend to a locked position under the action of a separate helical compression spring 76 to cover the needle 34. In this locked position, the needle guard 18 covens the needle 34 and protects the patient or a further person from needle 34 stick injuries.
The mechanism described utilises a parallel drive arrangement where the axis of the drive spring 74 is offset from the axis of the PFS 16, rather than passing into the bore of the PFS 16 as is common in the prior art. This arrangement has a number of advantages:
The simplicity of the mechanism results in a reduced number of components, which in turn helps to minimise the number of wall thicknesses required and hence device width and depth.
Due to the disposable nature of single-use auto-injectors 10, it is considered advantageous to minimise autoinjector 10 complexity, material usage, package size and assembly complexity in this way, as this all tends to reduce cost and environmental impact by:
The disclosure achieves this simplicity and small size whilst incorporating state of the art user features and adding innovative new user features.
In the following only the differences between the needle guard 18 and the inner body 80 will be discussed. Those parts of the needle guard 18 and the inner body 80 that are shown in the foregoing and not discussed in the following can likewise be provided at the corresponding component.
The cut-out 174 is present in the form of a profiled aperture 174′ that is at least generally L-shaped respectively is L-shaped, with the lock-out surface being arranged at a short limb 236 of the L-shaped cut-out 174.
The lock-out surface 234 is arranged at a short limb 236 at an angle to a long limb 238 of the L-shaped cut-out 174. The short limb 236 and the long limb 238 of the L-shaped cut-out 174 are arranged at an angle to one another, with the angle being selected in the range of 10 to 120°; in particular of 20 to 80°. In the present example the angle between the short limb 236 and the long limb 238 is 65°.
When assembled, the block 184′ on the compliant arm (clip arm 184) of the needle guard 18 is located within the profiled aperture 174′ of the inner body 80. The radial protrusion of the block 184′ from the general form of the complaint arm 184 ensures that the block 184′ overlaps the general radial wall thickness of the inner body 80.
The block 184′ of the clip arm 184 can be positioned such that there is a transverse clearance to the corresponding inner body lock-out surface 234, thus ensuring the lock-out surface 234 and the block 184′ cannot engage prior to triggering.
The clip arm 184 of the needle guard 18 can be moulded to nominally position the block lower than the aperture 174′, so that some deformation of the compliant arm 184 is required to achieve this assembled state, and therefore a transverse biasing force exists which holds the block 184′ in the position shown.
This restricts any transverse movement of the block 184′ whilst the dispense event is occurring.
The block 184′ travels along the long limb 238 of the profiled aperture 174 until full travel of the needle guard 18 is reached, which can be limited by an abutment in another area of the mechanism.
Axial movement of the block 184′ within the aperture 174 can be unrestricted. Alternatively it can be preferred to introduce detent features (not shown’) within the profiled aperture to provide a specific force feedback profile to the user during axial travel of the needle guard 18.
As the drive chassis 24 travels in the proximal direction along the axial direction A, contact occurs between the trigger arm 36 and the needle guard 18 in the transverse direction T. Initially this contact can occur with the needle guard 18, which can be considered rigid relative to the stiffness of the complaint trigger arm 36 (i.e. it is the trigger arm 36 that deflects, rather than the needle guard 18).
As the spring chassis 24 travel continues, the trigger arm 36 contacts the compliant arm 184 of the needle Guard 18. With the block 18′ guided within the long limb 238 of the profiled aperture 174, the block 184′ is prevented from being deflected, such that the needle guard complaint arm 184 becomes effectively rigid. The trigger arm 36 therefore continues to be displaced, or is displaced further, in the transverse direction T.
When the drive chassis 24 completes its axial travel, the trigger arm 36 can continue to be transversely defected due to contact with the needle guard 18. An angled surface is provided on the needle guard, to provide a gradual lead-in as contact with the trigger arm 36 transitions from the block 184′ at the end of the complaint arm 184 to the needle guard 18.
The geometry of the needle guard 18 is controlled to provide a smooth and progressive contact surface to the complaint trigger arm 36, so as not to generate force losses which could affect autoinjector 10 function. The complaint arm 184 of the needle guard 18 being built into the needle guard 18 at its distal end disposed opposite of the proximal end 92, and extending in a proximal direction, is advantageous in this respect.
As the needle guard 18 approaches the end of travel towards its proximal position, the block 184′ on the compliant arm 184 of the needle guard 18 passes the lock-out abutment surface 234 of the inner body and becomes axially aligned within the short limb 236 of the profiled aperture 174′. At this point, the biasing force, provided by contact and transverse deflection of the trigger arm 36, is sufficient to deflect the compliant arm 184 and block 184′ of the needle guard 18 into a raised position.
The geometry and material of the compliant arms 184 on the needle guard 18 and the drive chassis 24 are specified such that the trigger arm 36 is the stiffer and therefore the majority of the residual deflection occurs within in the compliant arm 184 of the needle guard 18.
Once this state is reached, the raised position of the block 184′ creates transverse overlap between a surface 240 of the block 184′ and the lock-out abutment surface 234. The needle guard 18 axial position is restricted to minimal movement between the surface 240 of the block 184′ and the lock-out abutment surface 234.
If the needle guard 18 is biased distally towards the housing 12 of the autoinjector 10, the surface 240 contacts the lock-out abutment surface 234, preventing further distal movement of the needle guard 18. The surfaces 240, 234 are angled to encourage further engagement of these surfaces 240, 234, via further deflection of the compliant arm 184. In this state, the requirements of needle 34 protection can be met.
The proximal end of the trigger arm 36 can raise to align transversely to the profiled aperture 174′ in the inner body 80. If this condition is reached, the end of the trigger arm 36 can move radially outwards, so that the trigger arm 36 becomes transversely restrained by the profiled aperture 174′. This state creates additional robustness, as the trigger arm 36 is locked in this raised state, creating maximum deflection in the complaint arm 184 in the needle guard 18 and maximising overlap between the surface 240 on the block 184′ and the lock-out abutment surface 234 on the inner body 80.
Further protection against high forces resulting from an impact event (autoinjector 10 is dropped) after use are provided by this mechanism. During a drop test the device must be decelerated from its impact velocity. Hence, the kinetic energy of the autoinjector 10 must be absorbed by the structure of the autoinjector 10, predominantly in the form of internal energy (stress & strain). If the distance over which the autoinjector 10 is decelerated can be increased, the forces required to decelerate the autoinjector 10 can be reduced. It is therefore advantageous to increase distance between the impact surface and the surfaces that restrict movement, so that the structural deflections are increased for a given applied load.
Thus, a respective one of the one or more trigger arms 36 is configured to engage a respective one of the one or more clip arms 184 on moving the needle guard 18 in the proximal direction between the dispensing state and the lock-out state.
Thus, a means of restricting axial travel of a needle protecting sleeve 230 (see
The inner body 80 has two profiled apertures 174′ as cut-outs 174 incorporated into respective sides of the inner body 80. There can be a single aperture 174′, but due to the general symmetry of the device, it can be beneficial to have a similar profiled aperture 174′ on both sides of the inner body 80.
At the proximal end of the aperture 174′, there can be two abutment surfaces 242, 244. There can be an assembly abutment surface 242, which provides the proximal abutment of the needle guard 18 prior to use. There can also be an extended abutment surface 244, which provides the proximal abutment of the needle guard 18 after use.
There can be an axial offset between the assembly abutment surface 242 and the extended abutment surface 244. Alternatively, there can be no axial offset between these surfaces 242, 244. These surfaces 242, 244 can be offset in the transverse direction, and the transverse width of the aperture 174′ at the proximal end can enable unrestricted movement between these abutment surfaces 242, 244 towards the distal end.
The profiled aperture 174′ can be narrower in the transverse direction than the transverse width of the aperture 174′ towards the proximal end, i.e. along the long limb 238. In particular, the width of the aperture 174′ towards the distal end can be matched to the transverse height of the block 184′, so that the block 184′ follows a defined path as the needle guard 18 travels in the distal direction.
The lock-out abutment surface 234 is arranged at the distal end of the short limb 236 of the aperture 174′. This lock-out abutment surface 234 provides a limit to distal travel of the needle guard 18. The moulded geometry described ensures that distal travel of the needle guard 18 is not restricted by this feature prior to use, but is restricted by this feature after a dispense event has occurred.
This block 184′ can also provide a limit of travel after use the proximal direction. The features which provides these proximal limits of travel are referred to as the assembly surface 242. After use, a proximal limit of travel is limited by the extended abutment surface 244, whereas the assembly surface 242 limits the proximal travel prior to use. This block 184′ can also provide a limit of travel after use in the distal direction, providing a lock-out abutment. The feature which provides the lock-out abutment is referred to as the ‘lock-out surface’ 234.
The one or more clip arms 184 extend in a proximal direction in parallel to the axial direction A from the needle guard 18. The one or more clip arms 184 extend in a proximal direction from the plunger arm 142 of the needle guard 18.
The needle guard 18 comprises a sleeve 230 at the proximal end 92 thereof. The needle guard 18 is of at least generally T-shaped design, with the plunger arm 142 being arranged in parallel to the axial direction A of the autoinjector 10 from the proximal end 92 to a distal end of said sleeve 230.
The sleeve 230 comprises one or more elongate slots 232 extending in parallel to the axial direction A of the autoinjector 10 from a proximal end to a distal end of said sleeve 230.
This further type of needle guard 18 and inner body 80 describe a mechanism to control the limits of travel of the needle guard 18 of the disposable autoinjector 10 used to dispense medicament from the pre-filled syringe 16. The mechanism disclosed permits full distal travel of the needle guard 18 to occur during initial use of the auto-injector, when a dispense event is initiated. After the dispensing event has occurred and the autoinjector 10 has been removed from the injection site, the mechanism enables the needle guard 18 to travel to a final proximal position. Once in the final position, the needle guard 18 is locked out to prevent further distal travel. This lock is intended to withstand sufficient axial force to provide the required protection from the needle 34, even in the event of an impact resulting from dropping the autoinjector 10.
The drive chassis 24 described in connection with the foregoing types of autoinjectors 10 can be used with the inner body 80 and the needle guard 18 and utilises the displacement of the Drive Chassis, which occurs during a dispense event, to provide the lock-out once the final position is reached. The forces required to axially displace the needle guard 18 into the final position are designed to be low, allowing the force output of the lock-out spring 76 to be minimised. This helps to achieve desirable low triggering forces, as the user must compress this spring 76 to operate the autoinjector 10.
When in the final position following dispense, the needle guard 18 achieves the lock-out, which must react sufficient force over sufficient travel to absorb the kinetic energy of the autoinjector 10 in an impact event. The mechanism provides an extended load path along the full length of the needle guard 18 and back along its compliant features and provides additional radial support of the compliant features to achieve both a high reaction load and a high displacement whilst loaded. Both of these combine to provide a large energy absorption capability, enabling the autoinjector 10 to better withstand impact events.
The mechanism requires no additional parts to be added to the autoinjector 10 described in
The needle guard 18 comprises two clip arms 184 each having a respective block 184′ that acts as a lockout block feature at the end of each of the two clip arms 184. The end surface of the respective clip arm 184 and of the block 184′ is known as an assembly stop feature 246.
On reaching the lock-out state the assembly stop feature 246 abuts the assembly abutment surface 242 of the inner body 80 as is shown e.g. in connection with
The clip arms 184 on the needle guard 18 are biased against the inside end face of the aperture 174′ in the inner body 80 to provide a stop limiting the travel of the needle guard 18 relative to the housing 12.
Towards the end of dose (EoD), the EoD click arm 250 of the inner body 80 engages with the EoD ramp 248 on the drive chassis 234 which deflects the EoD arm 250 transversely towards the centre of the device.
The EoD click arm 250 passes through the proximal end of the drive chassis 24 and drops off the end of the EoD ramp 248, rapidly releasing its stored energy and creating an audible click.
In this connection it should be noted that the click will always occur before the device reaches the ‘Fully Dispensed—Rigid Stopper’ condition. i.e. the position in which the plunger 26 can no longer move within the pre-filled syringe 16.
The EoD ramp 248 is arranged at the same or approximately the same axial position as a proximal end of the trigger arm 36 and of the first part outer surface 50 of the trigger limb 32.
It should further be noted that the web 42 also improves a damping function within the autoinjector 10. This is because when the drive chassis 24 impacts the plunger 26 during triggering of a dose, a large amount of energy is transferred to the syringe 16. If the load path is stiff, this can result in very high forces being applied to the flange of the syringe 16, causing it to break. The web 42 connecting the dispensing limb 22 to the trigger limb 32 provides a compliance between these two limbs 22, 32 which essentially reduces the force applied to the Syringe Flange during triggering of a dose.
In this connection it should be noted that the EoD click arm 250 can be arranged at an axial height of the inner body 80 within the inner body 80 ranging from 10% to 50%, preferably from 20 to 40%, of a length of the inner body 80 from the proximal end 92.
Providing the end of dose click in the manner described above using a click arm 250 cooperating with a ramp 248 results in a louder click in comparison to the design shown e.g. in
In contrast to the outer body 82 shown e.g. in
Moving the status indicator window 20 downwards, i.e. towards the proximal end makes the autoinjector 10 more diversely useable, as the number of components that must change to accommodate different PFS 16 fill volumes can be reduced.
This also has the effect that the drive chassis 10 will not appear behind the window in the pre-dispense condition, i.e. prior to activation of the autoinjector 10 a part is not visible in the status indicator window 20 that is subsequently visible.
It is possible in this connection to texture the status indicator window 20 so that the internal mechanism is obscured when the drive chassis 24 is at the distal end of the outer body 82 and hence not visible in the status indicator window 20.
When the dispense is finished, the drive chassis 24 will appear behind the status indicator window 20 and should flood it with colour. Only showing the drive cassis 24 in one state (the ‘dispense complete’ state) has the advantage that the drive chassis 24 does not have to be printed on its outer surface 49 as it only appears once.
In this connection it should be noted that the projection 86 shown in
It should further be noted that a length of the projection can be selected in the range of 5% to 50% of a length of the outer body 82, preferably in the range of 10% to 40% of a length of the outer body 82.
Also visible is the convex surface 152 of the stop feature 54 in
It should further be noted that the inner surface 118 of the outer wall 116 of the cap 70 comprises two ribs 120 at each longitudinal side, whereas the cap 70 shown in
In each case the needle shield holder 104 has two windows 112 of reduced size in comparison to the cap 70 shown e.g. in connection with
The windows 112 and the needle shield holder are respectively configured to hold the clip 252 in place, with the clip 252 in turn being configured to remove the removable needle shield 78 on removal of cap 70 from the autoinjector 10. For this purpose the clip 252 comprises barbs 254 that engage the respective windows 112.
As also indicated the free end of the clip 252 facing the removable needle shield 78 is configured to exert a pressure on the removable needle shield 78 such that on removal of the cap 70 the removable needle shield 78 is automatically also removed.
As is shown in
The drive chassis 24 is prevented from moving by the engagement of the two trigger arms 36 that engage the stop feature 54 of the outer body 82.
Each trigger arm 36 and stop feature comprises angled surface that are angled so that under the action of the axial force from the drive spring 74 on the drive chassis 24, the trigger arms 36 are biased into engagement and discouraged from moving either transversely or radially inwards relative to the stop feature 54.
The drive spring 74 is supported within the drive chassis 24 in a spring bore also known as the passage 140 and on the projection 86 of the outer body 82 also known as a spring support pin.
The inner body 80 and the outer body 82 are clipped together at the status indicator window clip joint formed by a protrusion 256 formed on the inner body, which fits inside the status indicator window 20 in the outer body 82.
The projections 108 of the needle shield holder 104 present at the cap 70 engage behind the distal end of the rigid needle shield 78. The distal end of the cap 70 is pressed against the inner body 80.
The lock-out spring 76 applies an axial force between the inner body 80 and the needle guard 18. The Syringe is radially supported by a syringe rib 258 in the inner body 80 and axially by a syringe flange ring 260 near the distal end of the inner body 80 (see
The syringe 16 is prevented from moving distally by ribs in the outer body 82 (and also by the RNS 78 engagement with the cap 70).
If a cut flange syringe is fitted, it can be prevented from rotating by providing further ribs (not shown) in the inner body 80.
In this connection it should be noted that the inner body 80 can comprise support elements (not shown) that support the trigger arms 36 of the drive chassis 24 during the storage state of the autoinjector 10.
Such support elements would be arranged at the distal end of the inner body 80 such that they engage the trigger arms 36 between 30% and 70% of their length to increase the stiffness of the trigger arms 36 and to act as a support that discourages unwanted disengagement of the trigger arms 36 from the stop feature 54.
At point of use, the user removes the cap 70, overcoming the snap fit connection 94, i.e. the projections 96 and removing the RNS 78 from the syringe 16 via the cap 70 having the projections 108 (or equivalent metal pressing as shown in
During this movement, the plunger arm 142 at the distal end of the needle guard 18 contacts the drive chassis 24 trigger arms 36 via the engagement surfaces 146 and pushes them transversely.
As the trigger arms 36 move transversely, they ride up the slope of the first planar surface 156, causing the drive chassis 24 to move slightly distally, which in turn causes the drive spring 74 to be slightly further compressed.
When the needle guard 18 has pushed the trigger arms 36 transversely over the apex 160 of the convex surface 152 acting as a trigger stop of the stop feature 54 of the outer body 82, the force from the drive spring 74 on the spring chassis 24 causes the trigger arms 36 to slide down the second planar surface 258, i.e. the steeper slope of the trigger stop.
When the trigger arms 36 release from the trigger stops, i.e. the stop feature under the action of the high force from the drive spring 74, an ‘audible click’ will be emitted (due to the sudden release of energy).
In this connection it should be noted that the concave surface 262 is formed complementary to the convex surface to minimize a clearance between the two components.
For this purpose, the concave surface 262 has a first planar portion 264 and a second planar portion 266 that connected to one another via a depression 268.
The needle guard 18 will continue to be displaced distally until it stops on rib features 270 on the inner body 80 as indicated in
As the drive chassis 24 advances in the proximal direction as indicated in
Once the trigger arms 36 are released from the stop feature 54 of the release mechanism 40, the drive chassis 24 is moved in the proximal direction under the action of the drive spring 74.
The dispensing limb 22 of the drive chassis 24 will contact and then begin to move the plunger 26 (there can initially be a gap), forcing the medicament through the needle 34. Once the plunger 26 has reached the “fully dispensed state”, the first part outer surface 50 of the drive chassis 24 begins to fill the status indicator window 20 so that the moulded (optionally bright) colour of the drive chassis 24 is visible through the window 20, providing a clear binary indication to the user that dispense is complete. Before dispensing, the drive chassis 24 is not visible directly behind the window 20 so it will look dark with some shadows of the device internals.
The drive spring 74 will continue to advance the drive chassis 24 until one of the following occurs (depending on the stopper compliance and tolerance condition of the components).
The projection 86 on the outer body 82 remains axially overlapped with the drive chassis 24 so that the drive spring 74 is fully supported (and prevented from buckling) all the way through dispense.
In an ideal situation the trigger arms 36 would require a low force to deform transversely i.e. be transversely flexible (to reduce the user force required to trigger the autoinjector 10) but be very stiff and strong axially (to avoid buckling under long term loads from the drive spring 74). To try to achieve this, the trigger arms 36 of the drive chassis can be formed thicker in the middle section (to increase buckling strength) and thinner at the root (to reduce transverse stiffness).
As indicated at the end of dispense in
The blocks 184′ at the end of the clip arms 184 are biased transversely (upwards in the image above) within the short limb 236 of the aperture 174′ of the inner body 80 by the trigger arms 36 of the drive chassis 24.
As the needle guard 18 moves proximally, the blocks 184′ are configured to move proximally along the long limb 238 and on reaching the short limb 236 the blocks 184′ are configured to be deflected by the trigger arms 36 and locked into the short limb 236.
The lock-out spring 76 biases the block 184′ in a proximal direction against the lock-out surface 234 of the aperture 174′, preventing the needle guard 18 from moving further in the proximal direction.
If the user removes the autoinjector from their skin before dispensing is finished, the needle guard 18 will be extended by the lock-out spring 76. The drive spring 74 will nevertheless continue to advance the drive chassis 24 within the syringe 16 and liquid will still be dispensed from the needle 34. During the remainder of the dispense, the trigger arms will move the needle guard 18 clip arms 184 into the locked position within the aperture 174′ as per a ‘normal’ dispense.
1. An autoinjector 10 comprising:
Number | Date | Country | Kind |
---|---|---|---|
21205085.0 | Oct 2021 | EP | regional |
21217555.8 | Dec 2021 | EP | regional |
22168393.1 | Apr 2022 | EP | regional |
This application is a U.S. National Stage application of PCT/EP2022/080000, filed Oct. 26, 2022, which claims priority to European Application No. 22168393.1, filed Apr. 14, 2022, U.S. application Ser. No. 17/668,071, filed Feb. 9, 2022, European Application No. 21217555.8, filed Dec. 23, 2021 and European Application No. 21205085.0, filed Oct. 27, 2021, the contents of each of which are hereby incorporated by reference.
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/EP2022/080000 | 10/26/2022 | WO |