Drug Delivery Device Subassembly

Abstract

A subassembly for a drug delivery device, the subassembly comprising a tubular cap (3, 3', 3''), an adapter (2, 2', 2''), a delivery member assembly (1) and a delivery member guard (4), wherein a rotation mechanism is disposed between the tubular cap (3, 3', 5 3'') and the adapter (2, 2', 2''), the rotation mechanism being configured to move the delivery member guard (4) from a distal position to a proximal position when a rotation of the adapter (2, 2', 2'') is caused relative to the tubular cap (3, 3', 3'') about a longitudinal axis (L).

Description

[Technical field]

[0001] The present disclosure relates generally to a subassembly of a medication delivery device, and more particularly to a subassembly having a rotation mechanism. [Background technology]

[0002] Drug delivery devices such as pen-type manual injectors or auto-injectors are commonly known for self-administration of drugs by patients without formal medical training. For example, a patient suffering from diabetes may require repeated injections of insulin, or a patient may require regular doses of other types of drugs, such as growth hormones.

[0003] A drug container, such as a cartridge or syringe, is often inserted or pre-installed into a portion of a drug delivery device. Because a cartridge can keep the contained drug completely sealed until a user wishes to perform a drug delivery action, a cartridge is usually more suitable for storing drugs for long periods of time than a syringe. However, a cartridge requires the user to attach a drug delivery member, such as a needle or nozzle, before use, which can be difficult for users without formal medical training.

[0004] Therefore, a drug delivery device that can automatically attach a drug delivery member is desirable. Summary of the Invention

[0005] The invention is defined by the claims appended hereto, to which reference should now be made.

[0006] In this disclosure, when the term "distal direction" is used, it refers to the direction away from the dose delivery site during use of the injection device. When the term "distal part / end" is used, it refers to the part / end of the delivery device, or the part / end of a member thereof, that is located the furthest from the dose delivery site during use of the injection device. Correspondingly, when the term "proximal direction" is used, it refers to the direction towards the dose delivery site during use of the injection device. When the term "proximal part / end" is used, it refers to the part / end of the delivery device, or the part / end of a member thereof, that is located the closest from the dose delivery site during use of the injection device.

[0007] Additionally, the terms "longitudinal," "longitudinally," "axially," or "axial" typically refer to a direction extending along a device or a component thereof from a proximal end to a distal end, in the direction of the greatest extension of the device and / or component.

[0008] Similarly, the terms "transverse," "transversal," and "transversally" refer to a direction generally perpendicular to the longitudinal direction.

[0009] Additionally, the terms "circumferential," "circumferential," or "circumferentially" refer to the circumference or direction relative to an axis, typically a central axis extending in the direction of the longest extension of a device and / or component. Similarly, "radial" or "radially" refers to a direction extending radially relative to an axis, and "rotation," "rotational," and "rotationally" refer to rotation relative to an axis.

[0010] Accordingly, a subassembly of a medication delivery device is provided, the subassembly comprising a tubular cap, an adapter, a delivery member assembly and a delivery member guard. The tubular cap extends along a longitudinal axis between a proximal end and a distal end. The delivery member assembly comprises a delivery member hub and a delivery member attached to the delivery member hub. The delivery member hub comprises a fastener configured to be attached to a counter fastener of a housing of the medication delivery device via relative rotation between the fastener and the counter fastener. The delivery member hub is rotatable relative to the housing of the medication delivery device about the longitudinal axis between an unattached position in which the fastener is not attached to the counter fastener and an attached position in which the fastener is attached to the counter fastener. The adapter comprises a body operatively connected to the delivery member hub, whereby the adapter is non-rotatable and axially movable relative to the delivery member hub. The adapter is disposed within the tubular cap. The adapter comprises a distally directed surface. The delivery member guard comprises a proximally directed surface adjacent the distally directed surface of the adapter. The delivery member guard is axially movable relative to the tubular cap from a distal position to a proximal position. The rotation mechanism is disposed between the tubular cap and the adapter. The rotation mechanism is configured such that when the delivery member guard moves from the distal position to the proximal position, a rotation of the adapter about the longitudinal axis relative to the tubular cap is caused, whereby the delivery member hub is moved from the unattached position to the attached position by rotation of the adapter.

[0011] Preferably, according to another embodiment, the rotation mechanism comprises a screw thread and a protrusion disposed within the screw thread, one of the screw thread and the protrusion extending from the body of the adapter, and the other of the screw thread and the protrusion extending from the body of the tubular cap toward the body of the adapter.

[0012] Preferably, according to another embodiment, the threads are disposed on an exterior surface of the body of the adapter. The tubular cap includes a distally extending arm extending from the body of the tubular cap in the direction of the longitudinal axis. The protrusion extends from the distally extending arm in a direction transverse to the longitudinal axis.

[0013] Alternatively, according to another embodiment, the threads are disposed on an inner surface of the body of the tubular cap. The projection extends from an outer surface of the body of the adapter in a direction transverse to the longitudinal axis.

[0014] Alternatively, according to another embodiment, the rotation mechanism includes a torsion spring wound about the longitudinal axis. The torsion spring extends between a first end and a second end. The first end is secured to the tubular cap. The second end is secured to the body of the adapter. The adapter includes an engagement member extending from the body of the adapter. The tubular cap includes an opposing engagement member that is circumferentially aligned with the engagement member of the adapter when the delivery member guard is in the distal position and that is circumferentially offset relative to the engagement member of the adapter when the delivery member guard is in the proximal position.

[0015] Preferably, according to another embodiment, the engagement member is a rib extending from an outer surface of the body of the adapter in a direction transverse to the longitudinal axis, and the counter engagement member is a notch in a wall of the body of the tubular cap.

[0016] Preferably, according to another embodiment, the adapter includes a flange extending from a body of the adapter. The flange defines a distally directed surface. A notch is disposed in the flange, and a second end of the torsion spring is mounted within the notch of the flange.

[0017] Preferably, according to another embodiment, the delivery member assembly includes a tubular inner cap. A delivery member hub is disposed within the tubular inner cap. The delivery member hub is non-rotatable and axially movable relative to the inner cap via a first engagement between the delivery member hub and the inner cap. The inner cap is disposed within the body. The inner cap is non-rotatable relative to the body of the adapter via a second engagement between the inner cap and the body of the adapter.

[0018] Preferably, according to another embodiment, the first engagement is formed by a longitudinally extending rib on the inner cap and a longitudinally extending rib on the delivery member hub.

[0019] Alternatively, according to another embodiment, the first engagement is formed by a longitudinally extending rib on the inner cap and a notch / recess on the delivery member hub, the notch / recess opening in a direction transverse to the longitudinal axis.

[0020] Alternatively, according to another embodiment, the first engagement is formed by a longitudinally extending rib on the delivery member hub and a notch / recess on the inner cap, the notch / recess opening in a direction transverse to the longitudinal axis.

[0021] Alternatively, according to another embodiment, the first engagement is formed by a non-circular cross-sectional body portion of the delivery member hub mating with a non-circular cross-sectional body portion of the inner cap.

[0022] Preferably, according to another embodiment, the second engagement is formed by a longitudinally extending rib on the inner cap and a longitudinally extending rib on the body of the adapter.

[0023] Alternatively, according to another embodiment, the second engagement is formed by a longitudinally extending rib on the inner cap and a notch / recess on the body of the adapter, the notch / recess opening in a direction transverse to the longitudinal axis.

[0024] Alternatively, according to another embodiment, the second engagement is formed by a longitudinally extending rib on the body of the adapter and a notch / recess on the inner cap, the notch / recess opening transversely to the longitudinal axis.

[0025] Alternatively, according to another embodiment, the second engagement is formed by a non-circular cross-sectional body portion of the adapter body mating with a non-circular cross-sectional body portion of the inner cap.

[0026] Preferably, according to another embodiment, the adapter is directly engaged with the delivery member hub via an engagement formed by longitudinally extending ribs on the delivery member hub and longitudinally extending ribs on the body of the adapter.

[0027] Alternatively, according to another embodiment, the adapter is directly engaged with the delivery member hub via an engagement formed by a longitudinally extending rib on the delivery member hub and a notch / recess on the body of the adapter, the notch / recess opening in a direction transverse to the longitudinal axis.

[0028] Alternatively, according to another embodiment, the adapter is directly engaged with the delivery member hub via an engagement formed by a longitudinally extending rib on the body of the adapter and a notch / recess on the delivery member hub, the notch / recess opening in a direction transverse to the longitudinal axis.

[0029] Alternatively, according to another embodiment, the adapter is directly engaged with the delivery member hub via engagement formed by a non-circular cross-sectional body portion of the adapter's body matching with a non-circular cross-sectional body portion of the delivery member hub.

[0030] Preferably, according to another embodiment, one of the fastener and the counterfastener is a thread and the other of the fastener and the counterfastener is a thread follower.The delivery member hub is axially movable in a distal direction of the tubular cap relative to the housing of the medication delivery device.

[0031] Alternatively, according to another embodiment, one of the fastener and counter-fastener is a bayonet track and the other of the fastener and counter-fastener is a bayonet track follower.

[0032] Preferably, according to another embodiment, the delivery member guard comprises a tubular body configured to surround the delivery member, the proximal end of the tubular body defining a proximally directed surface.

[0033] Another aspect of the invention provides a front subassembly for a medication delivery device, the front subassembly comprising a subassembly. The front subassembly comprises a body extending along a longitudinal axis from a proximal end to a distal end. A delivery member guard is coaxially mounted to the body and axially movable relative to the body along the longitudinal axis, and a locking member is mounted to the body. The locking member is movable relative to the delivery member guard between a locked position and an unlocked position. The locking member comprises a distally directed surface adjacent a second proximally directed surface of the delivery member guard in the locked position. The distally directed surface of the locking member is circumferentially spaced relative to the longitudinal axis from the proximally directed surface of the delivery member guard in the unlocked position.

[0034] Preferably, according to another embodiment, the locking member is rotatable relative to the delivery member guard about the longitudinal axis between a locked position and an unlocked position.

[0035] Preferably, according to another embodiment, the front sub-assembly includes a biasing member disposed between the distally oriented surface of the delivery member guard and the proximally oriented surface of the body.

[0036] Another aspect of the present invention provides a medication delivery device comprising a subassembly.

[0037] Another aspect of the present invention provides a medication delivery device that includes a front subassembly.

[0038] Preferably, according to another embodiment, the drug delivery device comprises a multi-chamber drug container disposed within a carrier.

[0039] Preferably, according to another embodiment, the drug delivery device is an automatic injector or a manual insulin pen.

[0040] Preferably, according to another embodiment, the medicament container is a cartridge.

[0041] Another aspect of the invention provides a method of attaching a delivery member to a drug delivery device, the method comprising, in order, the steps of providing a tubular cap extending along a longitudinal axis, the tubular cap housing an adapter, a delivery member hub, a delivery member secured to the delivery member hub, and a delivery member guard in contact with the adapter in the direction of the longitudinal axis, and using the delivery member guard to axially move the adapter towards the tubular cap in the direction of the longitudinal axis, thereby causing rotation of the adapter relative to the tubular cap about the longitudinal axis, thereby rotating the delivery member hub together with the adapter relative to the tubular cap, thereby attaching the delivery member to the drug delivery device by rotation of the delivery member hub.

[0042] Preferably, according to another embodiment, the step of causing rotation of the adapter relative to the tubular cap about the longitudinal axis by axially moving the adapter in the direction of the longitudinal axis using the delivery member guard includes the steps of axially moving the adapter out of a rotation block structure of the tubular cap using the delivery member guard and rotating the adapter using a torsion spring fixed between the tubular cap and the adapter.

[0043] Preferably, according to another embodiment, the step of causing rotation of the adapter relative to the tubular cap about the longitudinal axis by using the delivery member guard to axially move the adapter in the direction of the longitudinal axis includes rotating the adapter using a converter assembly configured to convert axial motion of the adapter into rotational motion of the adapter.

[0044] Preferably, according to another embodiment, the converter assembly is formed by a screw thread and a protrusion disposed on the screw thread, one of the screw thread and the protrusion being disposed on an outer surface of the adapter and the other of the screw thread and the protrusion being disposed on an inner surface of the tubular cap.

[0045] Preferably, according to another embodiment, the delivery member is attached to the medication delivery device via a threaded or bayonet connection between the delivery member hub and the medication delivery device.

[0046] The injection devices described herein can be used for the treatment and / or prevention of one or more of many different types of disorders. Exemplary disorders include, but are not limited to, rheumatoid arthritis, inflammatory bowel disease (e.g., Crohn's disease and ulcerative colitis), hypercholesterolemia, diabetes (e.g., type 2 diabetes), psoriasis, migraines, multiple sclerosis, anemia, lupus, atopic dermatitis, asthma, nasal polyps, acute hypoglycemia, obesity, anaphylaxis, and allergies. Exemplary types of drugs that may be included in the injection devices described herein include, but are not limited to, antibodies, proteins, fusion proteins, peptibodies, polypeptides, pegylated proteins, protein fragments, protein analogs, protein variants, protein precursors, and / or protein derivatives. Exemplary drugs that may be included in the injection devices described herein include, but are not limited to, the following (with non-limiting examples of associated disorders in parentheses): etanercept (rheumatoid arthritis, inflammatory bowel disease (e.g., Crohn's disease and ulcerative colitis)), evolocumab (hypercholesterolemia), exenatide (type 2 diabetes), secukinumab (psoriasis), erenumab (migraines), alirocumab (rheumatoid arthritis), methotrexate (amethopterin) (rheumatoid arthritis), tocilizumab (rheumatoid arthritis), interferon beta-1a (multiple sclerosis), sumatriptan (migraine), adalimumab (rheumatoid arthritis), darbepoetin alfa (anemia), belimumab (lupus), peginterferon beta-1a' (multiple sclerosis), sarilumab (rheumatoid arthritis), semaglutide (type 2 diabetes, obesity), dupilumab (atopic dermatitis, asthma, nasal polyps, allergies), glucagon (acute hypoglycemia), epinephrine (anaphylaxis), insulin (diabetes), atropine and vedolizumab (inflammatory bowel disease (e.g., Crohn's disease and ulcerative colitis)). Pharmaceutical formulations, including, but not limited to, any of the drugs described herein, such as a pharmaceutical formulation comprising a drug listed herein (or a pharma- ceutically acceptable salt of the drug) and a pharma- ceutically acceptable carrier, are also contemplated for use in the injection devices described herein.A pharmaceutical formulation containing a drug (or a pharma- ceutically acceptable salt of the drug) listed herein may contain one or more other active ingredients, or may be the only active ingredient present.

[0047] Moreover, all terms used in the claims are to be interpreted according to their ordinary meaning in the art, unless expressly specified otherwise herein. All references to elements, devices, components, means, etc. are to be openly interpreted as referring to at least one instance of the element, device, component, means, etc., unless expressly specified otherwise. [Brief description of the drawings]

[0048] Embodiments of the inventive concept will now be described, by way of example only, with reference to the accompanying drawings, in which: [Figure 1] FIG. 2 shows a schematic perspective view of a delivery member assembly of the subassembly of the present invention; [Diagram 2] FIG. 2 shows a schematic perspective view of a delivery member assembly of the subassembly of the present invention; [Diagram 3] FIG. 2 shows a schematic perspective view of a delivery member assembly of the subassembly of the present invention; [Figure 4A] 1 illustrates a schematic representation of an adapter of the present invention; [Figure 4B] 1 illustrates a schematic representation of an adapter of the present invention; [Diagram 5] FIG. 4C illustrates a perspective view of the delivery member assembly of FIGS. 1-3 with the adapter of FIGS. 4A-4B. [Figure 6] 1 shows a schematic perspective view of a portion of a tubular cap of the present invention; [Figure 7] 4A-4B and a tubular cap of the present invention. FIG. 4B shows a cross-sectional view of the delivery member assembly of FIGS. [Figure 8] FIG. 4 shows a schematic perspective view of the delivery member assembly of FIGS. 1-3 with an adapter of the present invention and a tubular cap of the present invention in another embodiment. [Figure 9] 1 shows a schematic perspective view of a delivery member guard of the present invention; [Figure 10] 1 shows a schematic perspective view of a subassembly of the present invention; [Figure 11] 13A and 13B are schematic perspective views of a subassembly of the present invention in another embodiment; [Figure 12] 13A and 13B are schematic perspective views of an adapter and torsion spring of the present invention in another embodiment; [Figure 13] FIG. 13 shows a schematic perspective view of the delivery member assembly of the tubular cap of the present invention in the example of FIG. 12. [Figure 14] FIG. 13 shows a schematic perspective view of the delivery member assembly of the tubular cap of the present invention in the example of FIG. 12. [Figure 15] 1 shows a schematic perspective view of a drug delivery device with which the subassembly of the present invention can be used; [Figure 16A] FIG. 16 shows a schematic perspective view of the locking member of the drug delivery of FIG. 15; [Figure 16B] FIG. 16 shows a schematic perspective view of the locking member of the drug delivery of FIG. 15; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0049] 1 to 14 show a subassembly of a drug delivery device comprising a tubular cap 3, 3', 3'', an adaptor 2, 2', 2'', a delivery member assembly 1 and a delivery member guard 4.

[0050] As shown in FIG. 6, the tubular cap 3, 3', 3'' extends along a longitudinal axis L between a proximal end and a distal end. The tubular cap 3, 3', 3'' comprises a body 30, 30', 30''. The tubular cap 3, 3', 3'' is configured to be gripped by a user and moved away from the drug delivery device prior to a drug delivery operation. As shown in FIG. 6, the tubular cap 3, 3', 3'' is generally cylindrical. Alternatively, the body of the tubular cap may comprise an elliptical or polygonal cross-section (viewed in the direction of the longitudinal axis) depending on the design needs of the drug delivery device.

[0051] 1-3, the delivery member assembly 1 comprises a delivery member hub 11 and a delivery member 12 attached to the delivery member hub 11, for example by adhesive or friction fit. The delivery member hub 11 comprises a fastener 112 configured to be attached to a counter fastener 132 of a housing of a medication delivery device via relative rotation between the fastener 112 and the counter fastener 132. The housing of the medication delivery device is configured to contain a medication for the medication delivery device.

[0052] Thus, when the delivery member hub 11 rotates relative to the housing of the drug delivery device, the delivery member hub 11 is attached to the housing of the drug delivery device via the fastener 112 and the counter fastener 132. Thus, fluid communication between the drug contained within the housing of the drug delivery device and the delivery member 12 can be established.

[0053] In one example, the counterfastener is an integral part of the housing of the drug delivery device. Alternatively, as shown in FIG. 2, the counterfastener 132 may be a separate component configured to be attached to the housing of the drug delivery device prior to the drug delivery operation, for example, via a snap-fit, bayonet engagement, or thread engagement. For example, as shown in FIG. 2, the counterfastener 132 is part of a retainer 13 with a snap-fit ​​arm 131 configured to be attached to the housing of the drug delivery device. In this example, the retainer 13 can be attached to the housing of the drug delivery device during manufacturing of the drug delivery device.

[0054] In this example, one of the fastener 112 and the counter fastener 132 is a thread and the other of the fastener 112 and the counter fastener 132 is a thread follower, e.g., a protrusion disposed within a thread or another thread. For example, as shown in FIG. 2, the fastener 112 is a thread and the counter fastener 132 is a thread. In this example, the delivery member hub 11 is axially and rotationally movable relative to the housing of the drug delivery device distally of the tubular cap 3, 3′, 3″ between an unattached position in which the fastener 112 is not attached to the counter fastener 132 and an attached position in which the fastener 112 is attached to the counter fastener 132.

[0055] Alternatively, one of the fastener and the counterfastener is a bayonet track and the other of the fastener and the counterfastener is a bayonet track follower. In this example, the delivery member hub 11 may be axially immobile relative to the housing of the drug delivery device and rotationally movable about the longitudinal axis L. For example, the bayonet track may be a circumferential groove with a notch (e.g., for manufacturing purposes) and the bayonet follower may be a protrusion disposed in the circumferential groove, such that rotation of the delivery member hub about the longitudinal axis relative to the housing can move the protrusion from an unattached position (e.g., closer to the end with the notch) to an attached position (e.g., farther away from the end with the notch).

[0056] Optionally, the delivery member assembly 1 comprises an inner cap 10, which is releasably attached to the housing of the drug delivery device via a rotational engagement. In one example, the rotational engagement is a threaded engagement, as shown in Figures 2-3. In this example, the inner cap 10 comprises a thread 102 and the housing of the drug delivery device comprises a reverse thread 133. In a preferred example, the reverse thread 133 extends from an outer surface of the retainer 13. Alternatively, the reverse thread may be an integral part of the housing of the drug delivery device.

[0057] In one example where the delivery member assembly includes an inner cap 10, a delivery member hub 11 is disposed within the tubular inner cap 10. The delivery member hub 11 is non-rotatable and axially movable relative to the inner cap 10 via a first engagement between the delivery member hub 11 and the inner cap 10. In one example, as shown in FIG. 3, the first engagement is formed by a notch 113 in the delivery member hub 11, the notch 113 being open in a direction transverse to the longitudinal axis, and the longitudinal rib 103 extending from the inner surface of the inner cap 10. It should be noted that the first engagement may also be formed by a longitudinally extending rib on the inner cap and a longitudinally extending rib on the delivery member hub, or the first engagement may be formed by a longitudinally extending rib on the delivery member hub and a notch / recess on the inner cap, the notch / recess being open in a direction transverse to the longitudinal axis, or the first engagement is formed by a non-circular cross-sectional body portion of the delivery member hub matching with a non-circular cross-sectional body portion of the inner cap.

[0058] In one example where the inner cap 10 is releasably attached to the housing of the drug delivery device via a thread engagement and the delivery member hub 11 is also attached to the housing of the drug delivery device via a thread engagement, the thread engagement between the inner cap 10 and the housing of the delivery member hub is a proximal oriented thread and the thread engagement between the delivery member hub 11 and the housing of the drug delivery device is a distal oriented thread. Thus, when the inner cap 10 rotates relative to the housing of the drug delivery device, the inner cap 10 can be moved away from the housing of the drug delivery device and removed from the housing via the proximal oriented thread engagement. Meanwhile, the delivery member hub 11 is rotated by the inner cap 10 relative to the housing of the drug delivery device via the first engagement. Thereby, the delivery member hub 11 can be moved towards the housing of the delivery member device and attached to the housing of the delivery member device via the distal oriented thread.

[0059] The adapter 2, 2', 2'' comprises a body 20, 20', 20'', as shown in Figures 4A-4B and 11, and is operably connected to the delivery member hub 11, whereby the adapter 2, 2', 2'' is non-rotatable and axially movable relative to the delivery member hub 11. The adapter 2, 2', 2'' is disposed within a tubular cap 3, 3', 3'', as shown in Figures 7-8, 10, and 13-14, and the adapter 2, 2', 2'' comprises a distally directed surface 20c, 21a'', as shown in Figures 4B and 11. In a preferred embodiment, the body 20, 20', 20'' of the adapter 2, 2', 2'' is a sleeve, as shown in Figures 4A-4B. Alternatively, the body of the adapter may be a ring or semicircle, or any suitable shape depending on the design. In a preferred embodiment, the adapter 2,2',2'' is configured to be axially movable relative to the tubular cap 3,3',3'' within a predetermined axial distance, such that when a user removes the tubular cap 3,3',3'' from the drug delivery device, the adapter 2,2',2'' can also be removed together with the tubular cap 3,3',3''. Examples of connections between the adapter 2,2',2'' and the tubular cap 3,3',3'' are described in detail below.

[0060] In one example where the delivery member assembly includes an inner cap 10, the inner cap 10 is disposed within the body 20, 20', 20'' of the adapter 2, 2', 2''. The inner cap 10 is non-rotatable relative to the body 20, 20', 20'' of the adapter 2, 2', 2'' via a second engagement between the inner cap 10 and the body 20. In a preferred example, the second engagement is formed by the non-circular cross-sectional body 20b of the body of the adapter 2, 2', 2'' mating with the non-circular cross-sectional body 101 of the inner cap 10, as shown in Figures 3 and 4B. Alternatively, the second engagement is formed by a longitudinally extending rib on the inner cap and a longitudinally extending rib on the body of the adapter. The second engagement is formed by a longitudinally extending rib on the inner cap and a notch / recess on the body of the adapter, the notch / recess opening in a direction transverse to the longitudinal axis, or the first engagement is formed by a longitudinally extending rib on the body of the adapter and a notch / recess on the inner cap, the notch / recess opening in a direction transverse to the longitudinal axis.

[0061] It should be noted that when a non-circular cross-section body of one component is used to mate with another non-circular cross-section body of another component, a rotational engagement is formed, which means that the two components can now only rotate together. For example, the non-circular cross-section body can be a polygonal cross-section body, a star-shaped cross-section body, or a heart-shaped cross-section body.

[0062] In this example, preferably, the adapter 2, 2', 2'' is axially attached to the inner cap 10. For example, the inner cap 10 includes a proximal neck portion 104, as shown in FIG. 2, and the adapter 2 includes a ledge 20d extending from an inner surface of the body 20 of the adapter 2 in a direction transverse to the longitudinal axis L, as shown in FIG. 4A. The ledge 20d engages the neck portion 104 of the inner cap 10, as shown in FIG. 5, such that the inner cap 10 is removed together with the adapter 2 when a user removes the adapter 2 from the medication delivery device.

[0063] In another example, the adapter is directly engaged with the delivery member hub via an engagement, which in this example may be formed by a longitudinally extending rib on the delivery member hub and a longitudinally extending rib on the body of the adapter, or the engagement is formed by a longitudinally extending rib on the delivery member hub and a notch / recess on the body of the adapter, the notch / recess opening in a direction transverse to the longitudinal axis, or the engagement is formed by a longitudinally extending rib on the body of the adapter and a notch / recess on the delivery member hub, the notch / recess opening in a direction transverse to the longitudinal axis, or the engagement is formed by a non-circular cross-sectional body portion of the body of the adapter mating with a non-circular cross-sectional body portion of the delivery member hub.

[0064] The delivery member guard 4 is axially movable from a distal position to a proximal position relative to the tubular cap 3, 3', 3''. In a preferred example, the delivery member guard 4 comprises a tubular body 40 configured to surround the delivery member 12. In a preferred example, as shown in FIG. 10, the delivery member guard 4 comprises a proximally oriented surface 40a adjacent to a distally oriented surface of the adapter 20c, 21a''. The proximal end of the tubular body 40 defines the proximally oriented surface 40a. Alternatively, the delivery member guard comprises a proximally oriented arm, the proximal end of the arm defining the proximally oriented surface. In another example, the delivery member guard 4 comprises a proximally oriented surface 42a adjacent to the distally oriented surface 32 of the tubular cap 3, as shown in FIG. 10. In a preferred example, the delivery member guard 4 comprises a distally extending arm 41. The distally extending arm 41 may include one or more protrusions 42, 43 for multiple design needs, such as to interact with a power pack to trigger a drug delivery operation and / or to interact with a lock so that the delivery member guard can be locked in a proximal position after use. For example, the proximally directed surface 42a may be defined by one protrusion 42.

[0065] It should be noted that FIG. 10 is drawn to show these two examples in the same view. However, preferably, the axial movement of the delivery guard 4 is configured to generate relative axial movement between the adapter 2 and the tubular cap 3, so that the delivery member guard 4 presses only against either the adapter 2 or the tubular cap 3. If the delivery member guard presses against both the adapter 2 and the tubular cap 3, a force adjustment design needs to be in place. For example, a damper or brake can be added either between the delivery member guard and the tubular cap, or between the delivery member guard and the adapter, thereby creating relative axial movement between the adapter 2 and the tubular cap 3.

[0066] The subassembly of the present invention further comprises a rotation mechanism disposed between the tubular cap 3,3',3' and the adapter 2,2',2''. The rotation mechanism is configured such that when rotation of the adapter 2,2',2'' is caused relative to the tubular cap 3,3',3'', about the longitudinal axis L, the delivery member guard 4 moves from a distal position to a proximal position, whereby the delivery member hub 11 is moved from a proximal position to a distal position by rotation of the adapter 2,2',2''.

[0067] In one example where one of the fastener 112 of the delivery member hub 11 and the counter fastener 132 of the housing of the medication delivery device is a thread and the other of the fastener 112 and the counter fastener 132 is a thread follower, the rotation direction of the adapter 2, 2', 2'' depends on the direction of the thread that can move the delivery member hub 11 distally relative to the tubular cap 3, 3', 3''. For example, if a clockwise rotation of the delivery member hub 11 (as viewed from the proximal end of the delivery member hub) moves the delivery member hub 11 distally relative to the tubular cap 3, 3', 3'', along the thread, the rotation mechanism is configured to rotate the adapter 2, 2', 2'' in a clockwise direction.

[0068] The adapter 2, 2', 2'' is operatively connected to the delivery member hub 11, and rotation of the adapter 2, 2', 2'' relative to the tubular cap 3, 3', 3'' rotates the delivery member hub 11 relative to the tubular cap 3, 3', 3''. The tubular cap 3, 3', 3'' remains stationary relative to the housing of the drug delivery device, and rotation of the delivery member hub 11 relative to the tubular cap 3, 3', 3'' moves the delivery member hub 11 from a proximal position where the fastener 112 is not attached to the counter fastener 132 to a distal position where the fastener 112 is attached to the counter fastener 132. Thus, the delivery member hub 11 and the delivery member 12 are attached to the housing of the drug delivery device as described above.

[0069] In one example, the rotation mechanism comprises threads 20a, 30a' and a protrusion 31b disposed within the threads 20a, 30a'. The threads 20a, 30a' and the protrusion 31b extend, on the one hand, from the adapter 2, 2', and the threads 20a, 30a' and the protrusion 31b extend, on the other hand, from the body 30, 30' of the tubular cap 3, 3' towards the body 20, 20' of the adapter 2, 2'.

[0070] In one example, the threads 20a are disposed on the outer surface of the adapter 2, as shown in FIG. 4A and FIG. 10. In this example, the projection 31b extends from the inner surface of the body 30 of the tubular cap 3 toward the body 20 of the adapter 2, as shown in FIG. 6-7 and FIG. 10. For example, the tubular cap 3 includes a distally extending arm 31 extending along the inner surface of the body 30. The distally extending arm 31 includes an arm body 31a from which the projection 31b extends. Alternatively, the projection 31b can extend directly from the body 30. In another example, the threads 30a' are disposed on the inner surface of the body 30' of the tubular cap 3', as shown in FIG. 8. In this example, the projection (not shown) extends from the outer surface of the body 20' of the adapter 2' toward the body 30' of the tubular cap 3'. As the delivery member guard 4 moves from a distal position to a proximal position, it moves the adapter 2, 2' in a proximal direction relative to the tubular cap 3, 3' following the threads, thereby rotating the adapter 2, 2' relative to the tubular cap 3, 3'. Alternatively, in one example where the delivery member guard 4 is engaged with the tubular cap 3, 3' as described above, the delivery member guard 4 can move the tubular cap 3, 3' relative to the adapter 2, 2' to rotate the adapter 2, 2', or the delivery member guard 4 can pull the tubular cap 3, 3' relative to the adapter 2, 2' to facilitate a user being required to rotate the adapter 2, 2'.

[0071] In one example, in which the adapter 2, 2' is configured to be axially movable relative to the tubular cap 3, 3' within a predetermined axial distance, the predetermined axial distance may be defined by threads and protrusions between the adapter 2, 2' and the tubular cap 3, 3'.

[0072] In another example, as shown in Figs. 11-14, the rotation mechanism includes a torsion spring 5 wound around a longitudinal axis L. The torsion spring 5 extends between a first end 51 and a second end 52. The first end 51 is fixed to the tubular cap 3''. In one example, a notch / recess 30a'' is in the wall of the body 30'' of the tubular cap 3'', and the first end 51 of the torsion spring is disposed within the notch / recess 30a'', as shown in Fig. 14. The second end 52 is fixed to the body 20'' of the adapter 2''. In one example, a notch / recess 21b'' is in the wall of the body 20'' of the adapter 2'', and the second end 52 of the torsion spring 5 is disposed within the notch / recess 21b'', as shown in Fig. 12. The adapter 2'' includes an engagement member 22 extending from the body 20'' of the adapter 2''. The tubular cap 3'' includes an opposing engagement member 31b'' that is circumferentially aligned with the engaging member 22 of the adapter 2'' when the delivery member guard 4 is in a distal position, as shown in Figure 13, and that is circumferentially offset relative to the engaging member 22 of the adapter 2'' when the delivery member guard 4 is in a proximal position, as shown in Figure 14. Thus, when the engaging member 22 is offset relative to the opposing engagement member 31b'', the torsion spring 5 rotates the adapter 2'' relative to the tubular cap 3''.

[0073] In one example, the engaging member 22 is a rib extending from the outer surface of the body 20'' of the adapter 2'' in a direction transverse to the longitudinal axis L, as shown in Figures 11-12. In this example, the counter engaging member 31b' is a notch in the wall of the body 30'' of the tubular cap 3''. Alternatively, the engaging member may be a notch / recess in the wall of the body of the adapter and the counter engaging member may be a rib extending from the inner surface of the body of the tubular cap.

[0074] In one example, the adapter 2'' includes a flange 21'' extending from a body 20'' of the adapter 2''. The flange 21'' defines a distally directed surface 21a', as shown in FIG. 12. Alternatively, the distal end of the body 20 of the adapter 2, 2' defines the distally directed surface 21a'. In one example where the adapter 2'' includes a flange 21'', the notch 21b'' is disposed in the flange 21''.

[0075] In one embodiment where the adapter 2'' is configured to be axially movable within a predetermined axial distance relative to the tubular cap 3'', the predetermined axial distance may be defined by a snap-fit ​​connection between the tubular cap 3'' and the adapter 2''. For example, the snap-fit ​​connection may be formed by an annular ledge on an inner surface of the body 30'' of the tubular cap 3'' and a hook on the body 20'' of the adapter 2''. The hook comprises a distally directed surface configured to engage the annular ledge when the delivery member guard 4 is in the proximal position.

[0076] The present invention further provides a front sub-assembly 6 for a drug delivery device, as shown in Figure 15. In a preferred embodiment, the front sub-assembly 6 is configured to be used in a cassette of a drug delivery device. A drug delivery device having a cassette is typically formed by a disposable cassette and a reusable drive unit 7. The cassette unit 6 comprises a drug container. The cassette 6 is configured to be attached to the drive unit 7 prior to a drug delivery operation.

[0077] The front subassembly comprises the subassembly defined above. The front subassembly further comprises a body 60 extending from a proximal end to a distal end along a longitudinal axis L. The delivery member guard 4 is coaxially mounted to the body 60 and axially movable relative to the body 60 along the longitudinal axis L. In a preferred example, the body 60 is a body of a cassette and is configured to house a drug container. In this example, the body 60 is configured to be mounted to a drive unit 7.

[0078] In a preferred example, the front subassembly includes a locking member 62 attached to the body 20. The locking member 62 is movable relative to the delivery member guard 4 between a locked position and an unlocked position. As shown in FIGS. 16A-16B, the locking member 62 includes a distally directed surface 622. The locking member 622′ is adjacent to the second proximally directed surface 43a of the delivery member guard 4 in the locked position, and the distally directed surface of the locking member 62 is circumferentially spaced relative to the longitudinal axis L from the proximally directed surface of the delivery member guard 4 in the unlocked position. For example, the notch 623 is aligned with the second proximally directed surface 43a of the delivery member guard 4 when the locking member 62 is in the unlocked position. Alternatively, the second proximally-directed surface 43a of the delivery member guard 4 is aligned with a distally-directed surface 622' that extends beyond the second distally-directed surface 623' in the distal direction of the body 60 in the locked position, and the delivery member guard 4 is aligned with the second distally-directed surface 623' in the unlocked position.

[0079] In a preferred example, the locking member 62 is rotatable relative to the delivery member guard 4 about the longitudinal axis L between a locked position and an unlocked position. Alternatively, the locking member is a pin that is slidable relative to the delivery member guard in a direction transverse to the longitudinal axis between a locked position and an unlocked position. In a preferred example, the locking member is configured to be removed from the delivery member guard and body in the unlocked position.

[0080] Thus, when the locking member 62 is in the unlocked position, the delivery member guard 4 can be moved from a proximal position to a distal position, thereby triggering the rotation mechanism of the subassembly as described above, thereby attaching the delivery member hub and delivery member to the body 60 (in this example, the body 60 is the housing of the drug delivery device), as described above.

[0081] In one example, the front subassembly comprises a biasing member disposed between a distally directed surface of the body 60 and a proximally directed surface of the other end of the delivery member guard 4, such that when the locking member 62 is in the unlocked position, the delivery member guard 4 is moved from the distal position to the proximal position by the biasing member. In another example, the delivery member guard 4 is moved from the distal position to the proximal position by the drive unit 7. For example, the drive unit comprises an arm extending from a wall of the drive unit toward the longitudinal axis L. When the body is attached to the drive unit, the arm pushes against a distal end of the delivery member guard, which moves the delivery member guard from the distal position to the proximal position.

[0082] The present invention further provides a method for attaching a delivery member to a medication delivery device. The method includes the steps of providing a tubular cap 3,3',3'', extending along a longitudinal axis L, the tubular cap 3,3',3'', which houses an adapter 2,2',2'', providing a delivery member hub 11, a delivery member 12 fixed to the delivery member hub 11, and a delivery member guard 4 in contact with the adapter 2,2',2'' in the direction of the longitudinal axis L, and then causing a rotation of the adapter 2,2',2'' about the longitudinal axis L relative to the tubular cap 3,3',3'', using the delivery member guard 4 to axially move the adapter 2,2',2'' in the direction of the longitudinal axis L towards the tubular cap 3,3',3'', thereby rotating the delivery member hub 11 together with the adapter 2,2',2'' relative to the tubular cap 3,3',3'', thereby attaching the delivery member 12 to the drug delivery device by rotation of the delivery member hub 11.

[0083] Preferably, the method includes the step of causing rotation of the adapter 2, 2', 2'' relative to the tubular cap 3, 3', 3'' about the longitudinal axis L and axially moving the adapter 2, 2', 2'' in the direction of the longitudinal axis L using the delivery member guard 4, wherein the moving step includes the step of rotating the adapter 2, 2', 2'' using a torsion spring 5 fixed between the tubular cap 3, 3', 3'' and the adapter 2, 2', 2'' using the delivery member guard 4 to axially move the adapter 2, 2', 2'' from the rotation block structure of the tubular cap 3, 3', 3''.

[0084] Preferably, the method includes the steps of inducing a rotation of the adapter 2, 2' relative to the tubular cap 3, 3'' about the longitudinal axis L and axially moving the adapter 2, 2' in the direction of the longitudinal axis L using the delivery member guard 4, the moving step including rotating the adapter 2, 2' using a converter assembly configured to convert an axial movement of the adapter into a rotational movement of the adapter 2, 2'. In a preferred example, the converter assembly is formed by a screw thread 20a, 30a and a protrusion 31b arranged on the screw thread. One of the screw thread and the protrusion is arranged on an outer surface of the adapter 2, 2' and the other of the screw thread and the protrusion is arranged on an inner surface of the tubular cap 3, 3'. In a preferred example, the delivery member is attached to the drug delivery device via a screw thread or a bayonet connection between the delivery member hub and the drug delivery device.

[0085] The inventive concept has been described above primarily with reference to certain examples, however, as will be readily appreciated by those skilled in the art, other embodiments besides those disclosed above are equally possible within the scope of the inventive concept as defined by the appended claims.

[0086] Certain aspects of the invention are described in the following clauses. Clause 1. A subassembly for a medication delivery device, the subassembly comprising: a tubular cap, an adapter, a delivery member assembly, and a delivery member guard; The tubular cap extends along a longitudinal axis between a proximal end and a distal end, The delivery member assembly comprises a delivery member hub and a delivery member attached to the delivery member hub, the delivery member hub comprising a fastener configured to be attached to a counter fastener of a housing of the medication delivery device via relative rotation between the fastener and the counter fastener, the delivery member hub being rotatable relative to the housing of the medication delivery device about a longitudinal axis between an unattached position in which the fastener is not attached to the counter fastener and an attached position in which the fastener is attached to the counter fastener; the adapter comprises a body operatively connected to the delivery member hub such that the adapter is non-rotatable and axially movable relative to the delivery member hub, the adapter is disposed within the tubular cap, the adapter comprises a distally directed surface; the delivery member guard includes a proximally directed surface adjacent the distally directed surface of the adapter, the delivery member guard being axially movable relative to the tubular cap from a distal position to a proximal position; A rotation mechanism is disposed between the tubular cap and the adapter, the rotation mechanism being configured to cause rotation of the adapter about the longitudinal axis relative to the tubular cap when the delivery member guard moves from the distal position to the proximal position, whereby the delivery member hub is moved from the unattached position to the attached position by rotation of the adapter, subassembly. Clause 2. A subassembly as described in clause 1, wherein the rotation mechanism comprises a screw thread and a protrusion disposed within the screw thread, one of the screw thread and the protrusion extending from the body of the adapter and the other of the screw thread and the protrusion extending from the body of the tubular cap toward the body of the adapter. Clause 3. A subassembly as described in clause 2, wherein the threads are disposed on an outer surface of the adapter body, the tubular cap includes a distally extending arm extending from the tubular cap body in a longitudinal axis direction, and the protrusion extends from the distally extending arm in a direction transverse to the longitudinal axis. Clause 4. The subassembly of clause 2, wherein the threads are disposed on an inner surface of the body of the tubular cap and the projection extends from an outer surface of the body of the adapter in a direction transverse to the longitudinal axis. Clause 5: The subassembly described in clause 1, wherein the rotation mechanism comprises a torsion spring wound around the longitudinal axis, the torsion spring extending between a first end and a second end, the first end being secured to the tubular cap and the second end being secured to the body of the adapter, the adapter comprising an engagement member extending from the body of the adapter, the tubular cap comprising an opposing engagement member circumferentially aligned with the engagement member of the adapter when the delivery member guard is in the distal position and circumferentially offset relative to the engagement member of the adapter when the delivery member guard is in the proximal position. Clause 6. The subassembly of clause 5, wherein the engagement member is a rib extending from an outer surface of the body of the adapter in a direction transverse to the longitudinal axis, and the opposing engagement member is a notch in a wall of the body of the tubular cap. Clause 7. The subassembly of clause 5 or 6, wherein the adapter includes a flange extending from a body of the adapter, the flange defining a distally directed surface, a notch disposed in the flange, and a second end of the torsion spring mounted within the notch in the flange. Clause 8. A subassembly described in any of clauses 1 to 7, wherein the delivery member assembly comprises a tubular inner cap, a delivery member hub disposed within the tubular inner cap, the delivery member hub being non-rotatable and axially movable relative to the inner cap via a first engagement between the delivery member hub and the inner cap, and the inner cap being disposed within the body, the inner cap being non-rotatable relative to the body of the adapter via a second engagement between the inner cap and the body of the adapter. Clause 9. The subassembly of clause 8, wherein the first engagement is formed by a longitudinally extending rib on the inner cap and a longitudinally extending rib on the delivery member hub, or the first engagement is formed by a longitudinally extending rib on the inner cap and a notch / recess on the delivery member hub, the notch / recess opening in a direction transverse to the longitudinal axis, or the first engagement is formed by a longitudinally extending rib on the delivery member hub and a notch / recess on the inner cap, the notch / recess opening in a direction transverse to the longitudinal axis, or the first engagement is formed by a non-circular cross-sectional body portion of the delivery member hub that aligns with the non-circular cross-sectional body portion of the inner cap. Clause 10. The subassembly of clause 8 or 9, wherein the second engagement is formed by a longitudinally extending rib on the inner cap and a longitudinally extending rib on the body of the adapter, or the second engagement is formed by a longitudinally extending rib on the inner cap and a notch / recess on the body of the adapter, the notch / recess opening in a direction transverse to the longitudinal axis, or the second engagement is formed by a longitudinally extending rib on the body of the adapter and a notch / recess on the inner cap, the notch / recess opening in a direction transverse to the longitudinal axis, or the second engagement is formed by a non-circular cross-sectional body portion of the body of the adapter mating with a non-circular cross-sectional body portion of the inner cap. Clause 11. A subassembly as described in any of clauses 1 to 7, wherein the adapter is directly engaged with the delivery member hub via engagement formed by longitudinally extending ribs on the delivery member hub and longitudinally extending ribs on the body of the adapter, or the engagement is formed by longitudinally extending ribs on the delivery member hub and notches / recesses on the body of the adapter, the notches / recesses opening in a direction transverse to the longitudinal axis, or the engagement is formed by longitudinally extending ribs on the body of the adapter and notches / recesses on the delivery member hub, the notches / recesses opening in a direction transverse to the longitudinal axis, or the engagement is formed by a non-circular cross-sectional body portion of the body of the adapter matching with the non-circular cross-sectional body portion of the delivery member hub. Clause 12. A subassembly as described in any of clauses 1 to 11, wherein one of the fastener and the counterfastener is a thread and the other of the fastener and the counterfastener is a thread follower, and the delivery member hub is axially movable in a distal direction of the tubular cap relative to the housing of the drug delivery device. Clause 13. The subassembly of any of clauses 1 to 12, wherein one of the fastener and the counter-fastener is a bayonet track and the other of the fastener and the counter-fastener is a bayonet track follower. Clause 14. The subassembly of any of clauses 1-13, wherein the delivery member guard comprises a tubular body configured to surround the delivery member, a proximal end of the tubular body defining a proximally directed surface. Clause 15. A front sub-assembly for a medication delivery device, the front sub-assembly comprising the sub-assembly of any of clauses 1 to 14, the front sub-assembly comprising: a body extending along a longitudinal axis from a proximal end to a distal end; a delivery member guard coaxially attached to the body and axially movable relative to the body along the longitudinal axis; A locking member attached to the main body, the locking member is movable relative to the delivery member guard between a locked position and an unlocked position; the locking member includes a distally directed surface adjacent a second proximally directed surface of the delivery member guard in the locked position; A front subassembly, the distally directed surface of the locking member being spaced circumferentially relative to the longitudinal axis from the proximally directed surface of the delivery member guard in the unlocked position. Clause 16. The front subassembly of clause 15, wherein the locking member is rotatable relative to the delivery member guard about the longitudinal axis between a locked position and an unlocked position. Clause 17. The front subassembly of clause 15 or 16, comprising a biasing member disposed between the distally directed surface of the delivery member guard and the proximally directed surface of the body. Clause 18. A drug delivery device comprising a front subassembly according to any one of clauses 15 to 17. Clause 19. A method of attaching a delivery member to a medication delivery device, the method comprising, in sequence: a tubular cap extending along a longitudinal axis, the tubular cap housing the adapter; A delivery member hub; a delivery member secured to a delivery member hub; a delivery member guard in contact with the adapter in the direction of the longitudinal axis; using the delivery member guard to axially move the adapter toward the tubular cap in the direction of the longitudinal axis, thereby causing rotation of the adapter relative to the tubular cap about the longitudinal axis, thereby rotating the delivery member hub together with the adapter relative to the tubular cap, thereby attaching the delivery member to the medication delivery device by rotation of the delivery member hub. Clause 20: The step of causing rotation of the adapter relative to the tubular cap about the longitudinal axis by using the delivery member guard to axially move the adapter in the direction of the longitudinal axis, axially displacing the adapter from the rotation block structure of the tubular cap using the delivery member guard; and rotating the adapter using a torsion spring secured between the tubular cap and the adapter. Clause 21: The step of causing rotation of the adapter relative to the tubular cap about the longitudinal axis by using the delivery member guard to axially move the adapter in the direction of the longitudinal axis, 20. The method of claim 19, comprising rotating the adapter using a converter assembly configured to convert axial motion of the adapter into rotational motion of the adapter. Clause 22. The method of clause 21, wherein the converter assembly is formed by a screw thread and a protrusion disposed on the screw thread, one of the screw thread and the protrusion being disposed on an outer surface of the adapter and the other of the screw thread and the protrusion being disposed on an inner surface of the tubular cap. Clause 23. A method according to any of clauses 19 to 22, wherein the delivery member is attached to the drug delivery device via a threaded or bayonet connection between the delivery member hub and the drug delivery device.

Claims

1. 1. A subassembly for a medication delivery device, the subassembly comprising: a tubular cap (3,3',3''), an adapter (2,2',2'), a delivery member assembly (1), and a delivery member guard (4); said tubular cap (3,3',3') extends along a longitudinal axis (L) between a proximal end and a distal end; the delivery member assembly (1) comprises a delivery member hub (11) and a delivery member (12) attached to the delivery member hub (11), the delivery member hub (11) comprising a fastener (112) configured to be attached to a counter fastener (132) of a housing of the drug delivery device via relative rotation between the fastener (112) and the counter fastener (132), the delivery member hub (11) being rotatable relative to the housing of the drug delivery device about the longitudinal axis (L) between an unattached position in which the fastener (112) is not attached to the counter fastener (132) and an attached position in which the fastener (112) is attached to the counter fastener (132); the adapter (2, 2', 2'') comprises a body (20, 20', 20'') operably connected to the delivery member hub (11), whereby the adapter (2, 2', 2') is non-rotatable and axially movable relative to the delivery member hub (11), the adapter (2, 2', 2') is disposed within a tubular cap (3, 3', 3''), the adapter comprising a distally directed surface (20c, 21a''); the delivery member guard (4) comprises a proximally directed surface (40a) adjacent the distally directed surface (20c, 21a'') of the adapter (2, 2', 2''); said delivery member guard (4) being axially movable from a distal position to a proximal position relative to said tubular cap (3, 3', 3'); a rotation mechanism is disposed between the tubular cap (3,3',3'') and the adapter (2,2',2''), and the rotation mechanism is configured such that when a rotation of the adapter (22',2'') is caused relative to the tubular cap (3,3',3'') about the longitudinal axis (L), the delivery member guard (4) moves from the distal position to the proximal position and the delivery member hub (11) moves from an unattached position to an attached position by rotation of the adapter (2,2',2'').

2. 2. The subassembly of claim 1, wherein the rotation mechanism comprises a screw thread (20a, 30a') and a protrusion (31b) disposed within the screw thread (20a, 30a'), one of the screw thread (20a, 30a') and the protrusion (31b) extending from the body (20, 20') of the adapter (2, 2') and the other of the screw thread (20a, 30a') and the protrusion (31b) extending from the body (30, 30') of the tubular cap (3, 3') towards the body (20, 20') of the adapter (2, 2').

3. 3. The subassembly of claim 2, wherein the threads (20a) are disposed on an outer surface of the body (20) of the adapter (2), the tubular cap (3) includes a distally extending arm (31a) extending from the tubular cap body (30) in the direction of the longitudinal axis (L), and the protrusion (31b) extends from the distally extending arm (31a) in a direction transverse to the longitudinal axis (L).

4. 3. The subassembly of claim 2, wherein the threads (30a') are disposed on an inner surface of the body (30') of the tubular cap (3') and the protrusion extends from an outer surface of the body (20') of the adapter (2') in a direction transverse to the longitudinal axis (L).

5. 2. The subassembly of claim 1, wherein the rotation mechanism comprises a torsion spring (5) wound around the longitudinal axis (L), the torsion spring (5) extending between a first end (51) and a second end (52), the first end (51) being fixed to the tubular cap (3'') and the second end (52) being fixed to the body (20'') of the adapter (2'), the adapter (2'') comprising an engagement member (22) extending from the body (20'') of the adapter (2''), the tubular cap (3'') comprising an opposing engagement member (31 b'') circumferentially aligned with the engagement member (22) of the adapter (2'') when the delivery member guard (4) is in the distal position and circumferentially offset relative to the engagement member (22) of the adapter (2'') when the delivery member guard (4) is in the proximal position.

6. 6. The subassembly of claim 5, wherein the engaging member (22) is a rib extending from an outer surface of the body (20'') of the adapter (2'') in a direction transverse to the longitudinal axis (L) and the opposing engaging member (31b') is a notch in a wall of the body (30'') of the tubular cap (3'').

7. 7. The subassembly of claim 5 or 6, wherein the adapter comprises a flange (21'') extending from the body (20'') of the adapter, the flange (21'') defining the distally directed surface (21a'), a notch (21b'') disposed in the flange (21''), and the second end (52) of the torsion spring (5) being mounted within the notch (21b'') of the flange (21'').

8. The delivery member assembly (1) comprises a tubular inner cap (10), the delivery member hub (11) is disposed within the tubular inner cap (10), the delivery member hub (11) is non-rotatable and axially movable relative to the inner cap (10) via a first engagement between the delivery member hub (11) and the inner cap (10), the inner cap (10) is disposed within the body (20, 20', 20''), and The inner cap (10) is attached to the body (20, 20', 20'') of the adapter (2, 2', 2'').

8. The subassembly of claim 1 , wherein the second engagement between the first and second bearings (20′, 20″) is non-rotatable via a second engagement between the first and second bearings (20′, 20″).

9. 9. The subassembly of claim 8, wherein the first engagement is formed by a longitudinally extending rib on the inner cap and a longitudinally extending rib on the delivery member hub, or the first engagement is formed by a longitudinally extending rib on the inner cap and a notch / recess on the delivery member hub, the notch / recess opening in a direction transverse to the longitudinal axis, or the first engagement is formed by a longitudinally extending rib on the delivery member hub and a notch / recess on the inner cap, the notch / recess opening in a direction transverse to the longitudinal axis, or the first engagement is formed by a non-circular cross-sectional body portion of the delivery member hub that mates with a non-circular cross-sectional body portion of the inner cap.

10. 10. The subassembly of claim 8 or 9, wherein the second engagement is formed by a longitudinally extending rib on the inner cap and a longitudinally extending rib on the body of the adapter; or the second engagement is formed by a longitudinally extending rib on the inner cap and a notch / recess on the body of the adapter, the notch / recess opening in a direction transverse to the longitudinal axis; or the second engagement is formed by a longitudinally extending rib on the body of the adapter and a notch / recess on the inner cap, the notch / recess opening in a direction transverse to the longitudinal axis; or the second engagement is formed by a non-circular cross-sectional body portion of the body of the adapter mating with a non-circular cross-sectional body portion of the inner cap.

11. 8. The subassembly of claim 1, wherein the adapter is directly engaged with the delivery member hub via engagement formed by a longitudinally extending rib on the delivery member hub and a longitudinally extending rib on the body of the adapter, or the engagement is formed by a longitudinally extending rib on the delivery member hub and a notch / recess on the body of the adapter, the notch / recess opening in a direction transverse to the longitudinal axis, or the engagement is formed by a longitudinally extending rib on the body of the adapter and a notch / recess on the delivery member hub, the notch / recess opening in a direction transverse to the longitudinal axis, or the engagement is formed by a non-circular cross-sectional body portion of the adapter body matching with a non-circular cross-sectional body portion of the delivery member hub.

12. 12. The subassembly of claim 1, wherein one of the fastener and the counterfastener is a thread and the other of the fastener and the counterfastener is a thread follower, and wherein the delivery member hub is axially movable distally of the tubular cap relative to the housing of the drug delivery device.

13. 13. The subassembly of any one of claims 1 to 12, wherein the delivery member guard (4) comprises a tubular body (40) configured to surround the delivery member (12), the proximal end of the tubular body (40) defining the proximally directed surface (40a).

14. A front sub-assembly for a medication delivery device, the front sub-assembly comprising the sub-assembly of any one of claims 1 to 13, the front sub-assembly comprising: a body (60) extending from a proximal end to a distal end along said longitudinal axis (L); the delivery member guard (4) coaxially attached to the body (60) and axially movable relative to the body (60) along the longitudinal axis (L); a locking member (62) attached to the body (20); the locking member (62) is movable relative to the delivery member guard (4) between a locked position and an unlocked position; a front sub-assembly, wherein the locking member (62) has a distally directed surface adjacent a second proximally directed surface (43a) of the delivery member guard (4) in the locked position, the distally directed surface of the locking member (62) being circumferentially spaced relative to the longitudinal axis (L) from the proximally directed surface of the delivery member guard (4) in the unlocked position.

15. 16. A front subassembly according to claim 15, wherein said locking member (62) is rotatable relative to said delivery member guard (4) about said longitudinal axis (L) between said locked and unlocked positions.

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