A drive assembly for a medicament delivery device and a medicament delivery device comprising the drive assembly

Abstract

The present disclosure relates to a drive assembly for a medicament delivery device (1), the drive assembly extending in a longitudinal (Y) direction extending between a proximal end and a distal end of the drive assembly, and in a transverse (X) direction being perpendicular to the longitudinal direction and comprising: a rod holder (17) having a central through-opening (17a) and a cam surface (17b), a plunger rod (19) comprising a cam follower (19a), a torsion member (21) operatively arranged to, upon activation, cause rotation of the plunger rod relative to the rod holder, wherein the plunger rod or the rod holder comprises a first locking surface (27), being a transversely extending surface, as seen relative to a longitudinal axis of the plunger rod, and the other one of the plunger rod and the rod holder comprises a second locking surface (29) abutting the first locking surface for restraining the plunger rod from movement in the proximal direction prior to activation.

Description

[0001] A DRIVE ASSEMBLY FOR A MEDICAMENT DELIVERY DEVICE AND A MEDICAMENT DELIVERY DEVICE COMPRISING THE DRIVE ASSEMBLY TECHNICAL FIELD

[0002] The present disclosure generally relates to medicament delivery devices such as autoinjectors or infusers, and particularly concerns a drive assembly for a medicament delivery device.

[0003] BACKGROUND

[0004] Medicament delivery devices, such as autoinjectors, generally include a plunger rod that is moved forward within a rod holder by a power source during drug administration. The medicament container may include a stopper positioned axially between the plunger rod and the medicament. During delivery, the plunger rod advances to push the stopper forward, directing the medicament towards and through the needle.

[0005] Prior to initiating drug delivery, there is generally an axial gap between the plunger rod and the stopper. Upon activation, the power source drives the plunger rod forward, closing this gap. Various types of power sources may be used for driving the plunger rod. Some autoinjectors comprise a rotational power source converting rotational motion into linear motion to drive the injection process. The power source may include a torsion spring, being a coiled spring storing energy. The torsion spring releases rotational energy translating into linear force to drive the plunger rod. Advantage with rotational power sources might be an enhanced precision and adjustable dosing mechanisms and / or a constant force to expel the medicament can be provided.

[0006] Rotational power sources may be facilitated by the interaction of a cam surface and a follower mechanism on the plunger rod and rod holder, respectively. The cooperation between the cam surface and the follower results in an initial rotation of the plunger rod relative to the rod holder, powered by the energy release of a torsion member, and may reduce the risk of excessive rotation of the torsion spring, preventing tangling of the torsion spring.

[0007] However, the incorporation of the cam surface presents a challenge, as it removes the capability to axially secure the plunger rod in place within an unused device. Hence, there is still a need to ensure axial stability while preserving the benefits provided by the cam mechanism.SUMMARY

[0008] An object of the present disclosure is to provide a drive assembly and a medicament delivery device comprising the drive assembly which solves, or at least mitigates problems of the prior art.

[0009] According to a first aspect of the present disclosure, there is provided a drive assembly for a medicament delivery device, the drive assembly extending between a proximal end and a distal end in a longitudinal direction, and in a transverse direction being perpendicular to the longitudinal direction and comprising:

[0010] a rod holder having a central through-opening and a cam surface,

[0011] a plunger rod operatively arranged to move within the through-opening of the rod holder, and comprising a follower configured to cooperate with the cam surface to enable rotation between the rod holder and the plunger rod,

[0012] a torsion member operatively arranged to, upon activation, cause rotation of the plunger rod relative to the rod holder,

[0013] wherein the plunger rod or the rod holder comprises a first locking surface, being a transversely extending surface, as seen relative to a longitudinal axis of the plunger rod, and the other one of the plunger rod and the rod holder comprises a second locking surface abutting the first locking surface for restraining the plunger rod from movement in the proximal direction prior to activation.

[0014] The provision of a cam surface and a follower on the plunger rod configured to cooperate with the cam surface to enable rotation between the rod holder and the plunger rod may reduce excessive rotation of the torsion member and prevent tangling. However, prior to activation of the plunger rod, such as when the drive assembly is in a deactivated state, there is a need to restrict axial movement of the plunger rod, such as to prevent axial drop of the plunger rod.

[0015] With “axial drop” is intended an unintentional axial movement of the plunger rod in a proximal direction. Such unintentional axial movement of the plunger rod could, for example, result from an unused medical delivery device being shaken or being dropped. An aim of the present disclosure is to prevent such undesired axial movement of the plunger rod.

[0016] In the present disclosure, when the term “distal direction” is used, this refers to the direction pointing away from the dose delivery site during use of the medicament delivery device. When the term “distal part / end” is used, this refers to the part / end of the delivery device, or the parts / ends of the components thereof, which under use of the medicament deliverydevice is / are located furthest away from the dose delivery site. Correspondingly, when the term “proximal direction” is used, this refers to the direction pointing towards the dose delivery site during use of the medicament delivery device. When the term “proximal part / end” is used, this refers to the part / end of the delivery device, or the parts / ends of the members thereof, which under use of the medicament delivery device is / are located closest to the dose delivery site.

[0017] Further, the term “longitudinal”, “longitudinally”, “axially” or “axial” refer to a direction extending from the proximal end to the distal end, typically along the device or components thereof in the direction of the longest extension of the device and / or component.

[0018] Similarly, the terms “transverse”, “transversal” and “transversally” refer to a direction generally perpendicular to the longitudinal direction.

[0019] Further, the terms “circumference”, “circumferential”, “circumferentially” refer to a circumference or a circumferential direction relative to an axis, typically a central axis extending in the direction of the longest extension of the device and / or component. Similarly, “radial” or “radially” refer to a direction extending radially relative to the axis, and “rotation”, “rotational” and “rotationally” refer to rotation relative to the axis.

[0020] According to one embodiment, the drive assembly is configurable in an initial deactivated state in which the plunger rod is arranged in a retracted position within the central through-opening of the rod holder, and configurable in an activated state in which the cam surface and the follower cause the rotation, such as an initial rotation, between the rod holder and the plunger rod as a result of the release of the torsion member to thereby cause the plunger rod to move forward in a proximal direction relative the rod holder.

[0021] According to one embodiment, the first locking surface extends at an angle within the range of from 10° to 90°, relative a longitudinal axis of the plunger rod, optionally 20° to 90° relative the longitudinal axis of the plunger rod, preferably 30° to 90°, relative a longitudinal axis of the plunger rod. The advantage of a first locking surface extending at an angle between 10° and 90° is that it effectively prevents undesired axial drop of the plunger rod relative to the rod holder, ensuring secure engagement and stability. At the same time, the angled design does not inhibit rotational motion, allowing for smooth and controlled adjustment or operation of the plunger rod as needed. This combination of axial locking and rotational freedom enhances the overall functionality and reliability of the mechanism.

[0022] According to one embodiment, the plunger rod or the rod holder comprises the first locking surface and the other one of the rod holder and the plunger rod comprises a protrusion, protruding out from the rod holder or the plunger rod in the transverse direction, wherein the protrusion comprises the second locking surface. Such configuration is a simple solution that ensures secure engagement to prevent undesired axial movement while allowing rotationalfreedom upon the activation of the drive assembly. This configuration enhances stability, durability, and functionality, making it ideal for applications requiring both locking and controlled rotational motion.

[0023] According to one embodiment, the first locking surface and the protrusion are configured to disengage from each other upon rotation between the rod holder and the plunger rod.

[0024] Further, in one embodiment, one of the plunger rod and the rod holder has a first thread and the other one of the rod holder and the plunger rod has a thread follower configured to cooperate with the first thread and wherein the first thread and the thread follower are configured to engage to enable further rotation of the plunger rod as a result of the release of the torsion member. Thus, their engagement converts the release of torsion energy from the torsion member into controlled rotational motion of the plunger rod.

[0025] The cam surface and the cam follower may thus be configured to cooperate to cause an initial rotation between the rod holder and the plunger rod and the first thread and the thread follower are configured to engage to cause further rotation of the plunger rod as a result of the release of the torsion member.

[0026] According to one embodiment, the rod holder comprises a locker thread and wherein the first locking surface forms part of an end section of the locker thread and the plunger rod comprises a protrusion, protruding out from the plunger rod in the transverse direction, wherein the protrusion comprises the second locking surface. The locker thread may optionally span an angular extent of 150° to 200° around the inner surface of the rod holder. Optionally, the locker thread may optionally span an angular extent of 160° to 190° around the inner surface of the rod holder. Optionally, the locker thread may optionally span an angular extent of 170° to 185° around the inner surface of the rod holder.

[0027] The fact that the rod holder comprises a locker thread and wherein the first locking surface forms part of an end section of the locker thread and the plunger rod comprises a protrusion according to the present disclosure offers a secure locking mechanism by preventing axial movement of the plunger rod in the first locked configuration. When the plunger rod is rotated, the protrusion disengages from the locker thread, transitioning the plunger rod into a second open configuration, thereby also providing ease of operation between the first locked configuration and the second opening configuration upon activation of the drive assembly. The “angular extent” of the locker thread herein refers to the portion of the rod holder’s inner circumference covered by the locker thread, as expressed in degrees. The rod holder is typically cylindrical, such that its inner surface forms a complete circle (360°). The locker thread is a section of the inner circular surface of the rod holder. If the locker thread span an angular extend of 150° to 200°, it does not cover the entire 360° of the inner surface but onlya segment. The angular extend thus refers to how much of this circular surface being occupied by the locker thread.

[0028] According to one embodiment, the protrusion on the plunger rod is configured to cooperate with the cam surface upon further rotation of the plunger rod. There may thus be a dual function of the protrusion, i.e. both to prevent axial movement of the plunger rod in the first locked configuration and to improve the rotational cooperation between the plunger rod and the rod holder.

[0029] According to one embodiment, the locker thread is positioned proximally, in the proximal direction of the drive assembly, relative the first thread prior to activation. The first thread or the thread follower being arranged on the plunger rod may be configured to cooperate with locker thread upon rotation of the plunger rod as a result of the release of the torsion member in the end of the activation state, i.e. when the plunger rod is in an extended state relative the rod holder. Such configuration prevents axial drop of the plunger rod when the plunger rod is in a locked state prior to activation and a continuous rotational control of the plunger rod during the active state.

[0030] According to one embodiment, the cam follower and the rod holder may be provided with a respective snap-fit lock element configured to rotationally secure the plunger rod, preventing movement prior to activation. The snap-fit elements may include a female element and a male element. The snap-fit lock elements may furthermore be configured to disengage from each other when subjected to a rotational force exerted by the torsion member upon activation of the drive assembly.

[0031] According to one embodiment, the cam surface forms part of a cam curve, the cam curve including a distal cam surface and a proximal opposing surface and a cam opening arranged between the distal cam surface and the proximal opposing surface, wherein the follower is configured to be in contact with and move along the distal cam surface during the rotation between the rod holder and the plunger rod and wherein the proximal opposing surface forms first locking surface. Hence, the cam follower will move within the cam curve during rotation of the plunger rod relative the rod holder and the distal cam surface will restrict the axial movement of the plunger rod before activation.

[0032] According to one embodiment, the proximal opposing surface of the cam curve comprises a first section and a second section, the second section being positioned distally, as seen in the proximal direction of the drive assembly, relative to the first section, the first section being the first locking surface and wherein the first section extends at a first angle relative the longitudinal axis of the plunger rod and the second section extends at a second angle relative the longitudinal axis of the plunger rod, wherein the first angle is greater than the second angle. The angle of the second section, relative the longitudinal axis of the plungerrod, may for example be around 0° or from around 0° to 20°. The fact that the proximal opposing surface of the cam curve comprises a first section and a second section according to the present disclosure, provides adequate space for the cam follower when the plunger rod is in its fully retracted position within the rod holder. Additionally, upon a slight axial movement of the plunger rod, the second section engages to limit further axial displacement, ensuring the plunger rod remains securely positioned before activation. Accordingly, the overall reliability and precision of the locking mechanism is improved during unintended activation and controlled engagement during operation is provided.

[0033] According to one embodiment, the first angle is within the range of from 30° to 80° relative the longitudinal axis of the plunger rod, optionally within the range of from 40° to 75° relative the longitudinal axis of the plunger rod. Such configuration may enhance the overall reliability and precision of the locking mechanism during pre-activation and ensures controlled engagement during operation.

[0034] According to one embodiment, the plunger rod comprises an axial support member connected to a proximal end of the plunger rod and configured to contact a stopper of a medicament container, the axial support member being connected to the rod holder at a proximal end of the rod holder prior to activation and being configured to disengage from the rod holder upon rotation between the rod holder and the plunger rod, wherein the rod holder or the axial support member comprising the first locking surface and the other one of the axial support member and the rod holder comprises the second locking surface. In this configuration, the plunger rod may thus comprise an additional component in the form of the axial support member.

[0035] The axial support member and the rod holder are releasably connected to each other, and the axial support member has a first function in the initial deactivated state of preventing axial displacement of the plunger rod by means of the first locking surface and upon activation, when the plunger rod starts to rotate and the cam follower slides along the cam surface transforming the moment to an axial force, the plunger rod axial force pushes on the axial support member. As the force increases the axial support member disengage from the rod holder.

[0036] According to one embodiment, one of the axial support member and the rod holder comprises a male part and the other one a mating female part configured to form a snap-fit connection with the male part. Meaning that the releasable connection between the rod holder and the axial support member is formed by the male and female part.

[0037] According to one embodiment, the rod holder comprises snap arms provided with the male part or with the female part. The snap arms are configured to hold the axial support memberprior to activation and configured to be flexed radially outwardly and release the axial support member upon rotation between the rod holder and the plunger rod.

[0038] The male and the female part may for example constitute of a rib and a mating groove. The rib and the groove may partly or completely extend around the circumference of the axial support member and the rod holder. The snap arms are configured to withstand the axial drop force from an axial drop of the plunger rod, which is low due to the light weight of the plunger rod. The snap arms are furthermore configured to release upon the axial force exerted upon activation of the drive assembly.

[0039] According to one embodiment, the snap arms comprise the male part in the form of an inwardly protruding flange and the axial support member comprises the mating female part in the form of a groove configured to form a snap-fit connection with the inwardly protruding flange.

[0040] According to one embodiment, the first locking surface is a surface of a locking ledge arranged at a proximal end of the rod holder and the plunger rod comprises a protrusion, protruding out from the plunger rod in the transverse direction, wherein the protrusion comprises the second locking surface. The protrusion may be the cam follower, with the second locking surface being a surface of the cam follower. The locking ledge may be positioned directly beneath the cam follower, as seen in the longitudinal direction, when the plunger rod is in its initial deactivated state. Meaning that when the plunger rod is in its initial deactivated state, the locking ledge prevents axial movement of the plunger rod. Upon activation and rotation of the plunger rod when the cam follower engages with and follows the cam surface, the cam follower moves past the locking ledge allowing continuous rotation of the plunger rod during the activated state.

[0041] According to one embodiment, the the drive assembly comprises a medicament container and a stopper arranged in the medicament container and wherein the plunger rod is configured to push the stopper in the proximal direction in the medicament container.

[0042] The provision of a cam surface and a cam follower enables an initial controlled impact speed with the stopper during the first axial displacement.

[0043] According to an embodiment, the plunger rod is arranged at a first axial distance from the stopper before the initial rotation of the plunger rod or the plunger rod holder, wherein a second axial distance travelled by the plunger rod as a result of the initial rotation is about the same as the first axial distance, or about plus minus 5 mm.

[0044] According to a second aspect of the present disclosure, there is provided a medicament delivery device comprising a drive assembly according to the first aspect.The medicament delivery member may for example be an autoinjector.

[0045] According to one embodiment, the medicament delivery member comprises a housing, wherein the plunger rod holder is rotationally fixed relative to the housing.

[0046] Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a / an / the member, apparatus, component, means, etc.” are to be interpreted openly as referring to at least one instance of the member, apparatus, component, means, etc., unless explicitly stated otherwise.

[0047] BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The specific embodiments of the inventive concept will now be described, by way of example, with reference to the accompanying drawings, in which:

[0049] Fig. 1 is a perspective view of a medicament delivery device according to embodiments of the present disclosure;

[0050] Fig. 2 is an exploded view of the medicament delivery device in Fig. 1 ;

[0051] Fig. 3 is a perspective view of a rod holder according to embodiments of the present disclosure;

[0052] Fig. 4 is a perspective view of an alternative rod holder according to embodiments of the present disclosure;

[0053] Fig. 5A illustrates a rod holder and a plunger rod in a first locked state according to embodiments of the present disclosure;

[0054] Fig. 5B illustrates the rod holder and the plunger rod shown in Fig. 5A after an initial rotation of the plunger rod relative the rod holder;

[0055] Fig. 6 is an exploded view of a rod holder and a plunger rod according to embodiments of the present disclosure; and

[0056] Fig. 7 is a section view of the rod holder and the plunger rod shown in Fig. 6 when the plunger rod is received in the rod holder.

[0057] DETAILED DESCRIPTION

[0058] The inventive concept will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplifying embodiments are shown. The inventive concept may, however, be embodied in many different forms and should not be construed aslimited to the embodiments set forth herein; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the inventive concept to those skilled in the art. Like numbers refer to like members throughout the description.

[0059] Fig. 1 is a perspective view of a medicament delivery device 1. The medicament delivery device 1 is an example of a device comprising an embodiment of a drive assembly according to the present disclosure.

[0060] The medicament delivery device 1 comprises a housing 3. The housing 3 in Fig. 1 comprises a front part 3a and a rear part 3b. It should, however, be noted that this is an optional feature and the front and rear parts 3a, 3b may be separate as illustrated in Fig. 1 or merged into one unit.

[0061] The medicament delivery device 1 may have a removable cap. In Fig. 1 , the cap has been removed.

[0062] The medicament delivery device 1 comprises a delivery member cover 5. The delivery member cover 5 is at least partly received by the housing 3. The delivery member cover 5 is configured to move along the longitudinal Y axis of the medicament delivery device 1. The delivery member cover 5 is configured to move between an extended position, shown in Fig.

[0063] 1 , and a retracted position relative to the housing 3. The delivery member cover 5 protrudes from the housing 3 in the extended position and is pushed further into the housing 3 in the retracted position.

[0064] The medicament delivery device 1 has a proximal end 7a and a distal end 7b. According to the example, a front end of the delivery member cover 5 defines the proximal end 7a when the cap has been removed and the delivery member cover 5 is in the extended position. The distal end 7b is the rear end of the medicament delivery device 1.

[0065] Fig. 2 is an exploded view of the exemplified medicament delivery device 1. It should, however, be noted that the specific medicament delivery device illustrated in Figures 1 and 2 is just an example of a medicament delivery device 1 and should not be construed as limiting for the present invention disclosed herein.

[0066] The medicament delivery device 1 comprises a resilient member 9, configured to bias the delivery member cover 5 towards the extended position. The resilient member 9 may be a spring, such as a compression spring.

[0067] The medicament delivery device 1 comprises a container holder 11 configured to be axially and rotationally fixed relative to the housing 3. In this figure, the container holder 11 is depicted with a front part 3a and rear part 3b. However, this is not mandatory. The container holder 11 is not limited to this specific configuration but may for example, and alternatively, constitute of one single unit.The container holder 11 is configured to hold a medicament container 13, such as a syringe provided with a needle. The medicament container 13 contains the drug to be administered. A stopper 15 is slidably arranged in the medicament container 13. The stopper 15 keeps the distal end of the medicament container 13 sealed.

[0068] The medicament delivery device 1 comprises a drive assembly. The drive assembly comprises a rod holder 17, a plunger rod 19, and a torsion member 21. The torsion member 21 may for example be a torsion spring. The torsion member 21 is operatively arranged to, upon activation, cause rotation of the plunger rod 19 relative to the rod holder 17.

[0069] The drive assembly extends in a longitudinal direction Y between a proximal end and a distal end of the drive assembly and in a transverse direction X being perpendicular to the longitudinal direction Y. According to the example, a front end of the rod holder 17 defines the proximal end of the drive assembly when the plunger rod is in a retracted position and a rear end of the torsion member 21 defines the distal end.

[0070] The rod holder 17 has a central through-opening 17a and a cam surface 17b. The plunger rod 19 is operatively arranged to move within the through-opening 17a of the rod holder 17. The plunger rod 19 has a cam follower 19a configured to cooperate with the cam surface 17b to enable rotation between the rod holder 17 and the plunger rod 17b.

[0071] In this example the plunger rod 19 has a first thread 19b. The first thread 19b is arranged on the outer surface of the plunger rod 19. The plunger rod may be provided with a thread follower, not shown.

[0072] Alternatively, the rod holder may comprise the first thread, arranged on an inner surface defining the central through-opening 17a and the plunger rod may be provided with the thread follower. The thread follower may for example be a thread or a protrusion configured to co-operate with the first thread.

[0073] According to the example, one end of the torsion member 21 is connected to the rotator 25. The other end of the torsion member 21 is connected to one of the components of the rear cap assembly 26. The rear cap assembly 26 may be rotationally fixedly arranged relative to the housing 3. The torsion member 21 is configured to provide torsional bias of the rotator 25. The torsion member 21 is thus configured to cause rotation of the rotator 25.

[0074] The release member 23 is configured to maintain the rotator 25 rotationally fixed relative to the housing 3 when the delivery member cover 5 is in the extended position. The rod holder 17 may be provided with arms 17c, around which the release member 23 is arranged when the delivery member cover 5 is in the extended position. The arms 17c may have teeth configured to engage with corresponding teeth 25a on the outer surface of the rotator 25. The teeth of the arms and the teeth of the rotator may form a ratchet structure.The release member 23 pushes the arms 17c radially inwards such that the ratchet structure locks and prevents rotation of the rotator 25. When the delivery member cover 5 is moved from the extended position to the retracted 5 position, distally directed legs 5a, 5b of the deliver member cover 5 push the release member 23 in the distal direction, causing the release member 23 to move in the distal direction, away from the arms 17c, which as a result are flexed radially outwards. The rotator 25 is thus released from being rotationally locked, and the torsion member 21 will thus cause rotation of the rotator 25 as the torsion member 21 releases its stored energy.

[0075] The rotator 25 has an axial channel in which the plunger rod 19 is arranged to be at least partly received. The rotator 25 may have a keyed slot or keyway and the plunger rod 19 may have a corresponding keyseat engaging with the keyed slot or keyway. By rotation of the rotator 25, the plunger rod 19 is 15 rotated concurrently with the rotator 25.

[0076] In this embodiment, the rod holder 17 comprises a first locking surface 27, see Fig. 3 or 4, being a transversely extending surface, as seen relative to a longitudinal Y axis of the plunger rod 19, and the plunger rod 19 comprises a second locking surface 29 abutting the first locking surface 27 for restraining the plunger rod 19 from movement in the proximal direction prior to activation.

[0077] It should be noted, however, that in an alternative embodiment, the plunger rod may comprise the first locking surface, while the rod holder comprises the second locking surface 29, which abuts the first locking surface 27.

[0078] Figs. 3 and 4 illustrate alternative embodiments of the present disclosure. Each of Figs. 3 and 4 illustrate the rod holder 17, as seen from a proximal end thereof. The rod holders 17 includes the central through-opening 17a and the cam surface 17b. The cam surface 17b is formed by an inner wall of the rod holder 17 that defines the central through-opening 17a. When the plunger rod 19, see Fig. 2, is operatively arranged to move within the through-opening 17a of the rod holder 17, the cam follower 19a is configured to cooperate with the cam surface 17b. The cam follower 19 illustrated in Fig. 2 is a radially extending protrusion provided on the plunger rod 19.

[0079] Prior to activation, the cam follower 19a is located in the beginning of the cam surface 17b and the cam follower 19a is in contact with the cam surface 17b.

[0080] The rod holders 17 illustrated in each of Figs. 3 and 4 comprise a respective first locking surface 27, being a transversely extending surface, as seen relative to a longitudinal axis Ya. In these respective embodiments, the cam follower 19a comprises the second locking surface 29 which, upon axial movement in the proximal direction, will abut the first locking surface 27 and thereby restrains the plunger rod 19 from movement in the proximal direction prior to activation.In each of Figs. 3 and 4, the first locking surface 27 extends at an angle a within the range of from 10° to 90°, relative the longitudinal axis Ya of the plunger rod 19, optionally 20° to 90°, or 30° to 90°, relative the longitudinal axis Ya of the plunger rod 19. More specifically, the first locking surface 27 in the embodiment illustrated in Fig. 3 extends with an angle a within the range of from 30° to 45°, relative the longitudinal axis Ya of the plunger rod 19, while the first locking surface 27 in the embodiment illustrated in Fig. 4 extends with an angle of about 90°, relative the longitudinal axis Ya of the plunger rod 19.

[0081] In the embodiment illustrated in Fig. 3. the rod holder 17 comprises a cam curve 31 including a distal cam surface 33, corresponding to the cam surface 17b, a proximal opposing surface 35 and a cam opening arranged between the distal cam surface 33 and the proximal opposing surface 35. The cam follower 19a is configured to be in contact with and move along the distal cam surface 33, i.e. the cam surface 17b, at activation when the cam follower 19 slides along the distal cam surface 33 / cam surface 17b. The proximal opposing surface 35 forms the first locking surface 27. In this embodiment a proximal surface of the cam follower 19a constitutes the second locking surface 29. In case of axial displacement of the plunger rod 17 before activation, the proximal opposing surface 35 restrains the plunger rod 19 from movement in the proximal direction prior to activation by contacting the proximal opposing surface 35, i.e. the first locking surface 27. While the cam follower 19a may not necessarily remain in constant contact with the proximal opposing surface 35 of the cam curve 31 at all times before activation, any minor axial displacement of the plunger rod will cause the proximal opposing surface 35 of the cam curve 31 to act as a physical barrier. In the example illustrated in Fig. 3, the proximal opposing surface 35 of the cam curve 31 comprises a first section 35a and a second section 35b. The first section 35a is positioned distally relative to the second section 35b, as seen in the proximal direction of the drive assembly. The second section 35b functions as the first locking surface 27.

[0082] The first section 35a is inclined at a first angle a, relative to the longitudinal axis Ya of the plunger rod 19, while the second section 35b is inclined at a second angle B relative to the same axis. Notably, the second angle B is greater than the first angle a. Specifically, the second angle B is within the range of from 30° to 80° relative the longitudinal axis Yaof the plunger rod 19, optionally within the range of from 40° to 75° relative the longitudinal axis Yaof the plunger rod 19. In contrast, the first angle a may for example range from 0° to 25°. In Fig. 4, the first locking surface 27 is formed by a surface on a locking ledge 37 located at a proximal end of the rod holder 17. In this embodiment a proximal surface of the cam follower 19a constitutes the second locking surface 29. In Fig. 4, the locking ledge 37 is positioned directly beneath the cam follower 19a, along the longitudinal axis Yawhen the plunger rod is in its initial deactivated state. Hence the locking ledge 37 prevents axial movement of the plunger rod 19 prior to activation by abutment with the cam follower 19a, and morespecifically the proximal surface of the cam follower, here corresponding to the second locking surface 29.

[0083] Similar to the embodiment depicted in Fig. 3, the second locking surface 29 of the cam follower 19a and the locking ledge 37 are not in constant abutment before activation.

[0084] However, any minor axial displacement of the plunger rod will cause the locking ledge 37 to act as a physical barrier. This occurs when the second locking surface 29 of the cam follower 19 abuts the locking ledge 37 thereby preventing further axial movement., i.e. through abutment of the first locking surfaces 27 of the locking ledge 37 and second locking surfaces 29 of the cam follower 19a.

[0085] Figs.5A and 5B illustrate the plunger holder 17 and the plunger rod 19 of the drive assembly according to a further embodiment of the present disclosure. In this example the rod holder 17 comprises a locker thread 39 and the first locking surface 27 forms part of an end section of the locker thread 39. The plunger rod 19 comprises a protrusion 41 comprising the second locking surface 29, being a transversely extending surface, as seen relative to a longitudinal axis Yaof the plunger rod 19.

[0086] The locker thread 39 spans an angular extent of 150° to 200° around the inner surface of the rod holder 17. Optionally, the locker thread 39 spans an angular extent of 160° to 190° around the inner surface of the rod holder 17. Optionally, the locker thread 39 may optionally span an angular extent of 170° to 185° around the inner surface of the rod holder 17.

[0087] The locker thread 39 is positioned proximally, in the proximal direction of the drive assembly, relative the first thread 19b before activation of the drive assembly. The first thread 19b on the plunger rod 19 is configured to engage with the locker thread 39 upon rotation of the plunger rod at the end of the activation state, i.e. when the plunger rod 19 is in an extended position relative the rod holder 17.

[0088] This configuration prevents axial displacement or drop of the plunger rod 19 while it is in a locked state before activation. Additionally, it ensures continuous rotational control of the plunger rod 19 during the activated state, contributing to precise operation.

[0089] Fig. 5B illustrates the initial rotation between the plunger rod 19 and the rod holder 17 in the activated state. As the plunger rod 19 rotated relative to the rod holder 17, the protrusion 41 disengages from the locker thread 39, transitioning the plunger rod 19 into a second open configuration.

[0090] Before activation, the locker thread 39 is positioned proximally, in the proximal direction of the drive assembly, relative to the first thread 19b. The first thread 19b may be configured to engage with locker thread 39 during rotation of the plunger rod 39.Figs. 6 and 7 illustrate a further embodiment in which the plunger rod 19 includes an axial support member 19’. The trust bearing 19’ is connected to a proximal end 43 of the plunger rod 19. The axial support member 19’ is configured to contact a stopper 15 of a medicament container 13 and is releasably connected to the rod holder 17 at a proximal end 45 of the rod holder 17 prior to activation of the drive assembly.

[0091] The axial support member 19’ is configured to disengage from the rod holder 17 upon the rotation of the plunger rod 19 relative the rod holder 17, i.e. upon activation of the drive assembly. In this configuration, the plunger rod 19 thus comprises an additional component in the form of the axial support member 19’. In the illustrated example, the rod holder 17 comprises snap arms 47 connected to an end portion 49 of the axial support member 19’. The snap arms 47 comprises a male part 51 in the form of a flange protruding, in the transverse direction X from a proximal edge of the snap arms 47. The male part 51 is configured to engage in a mating female part 53 in the form of a circumferential groove of the axial support member 19’, thereby forming a snap-fit connection.

[0092] The first locking surface 27 is arranged on the rod holder 17 and defined by a surface of the male part 51 of the snap arms 47. The second locking surface 29 is arranged on the axial support member and is a surface of the female part 53 abutting the first locking surface 27 during before activation of the drive assembly, thereby restraining the plunger rod 19 from movement in the proximal direction before activation.

[0093] The snap arms 47 are configured to withstand the axial force generated by the plunger rod 19 during an axial drop. This force is minimal due to the lightweight nature of the plunger rod 19. Additionally, the snap arms 47 are configured to be flexed radially outwardly and release the axial support member 19’ upon rotation between the rod holder 17 and the plunger rod 19.

[0094] In this example, the end portion 49 of the axial support member 19’ is connected to the proximal end of the plunger rod 19 by means of a snap-fit connection including an inwardly protruding male element 55, in the form of a circumferential inner rib. This male element 55 forms a snap-fit connection with a neck portion 57 at the proximal end 43 of the plunger rod 19.

[0095] A medicament delivery device (such as an autoinjector) may generally include various other components. For example, a sensor unit which may recognize medicament delivery events, such as the needle inserted into an attachment portion of e.g., a pad, injection started, and medicament delivery operation ends, a memory unit which is configured to store the recorded data during the medicament delivery operation, a connectivity unit configured to transmit the stored data to a smart device or the network directly, a processing unit configured to control the entire system and processes the data before transmitting it, and / oruser interface units that are configured to provide feedback to the patient, such as status LEDs, haptic, and / or audio feedback.

[0096] When the medicament delivery device is placed into the attachment portion, the sensors inside of the pad are configured to recognize the event and give feedback to the patient via haptic / visual or audio elements.

[0097] When the medicament delivery finishes, the sensors are configured to recognize the event and give feedback to the patient again. Further, the collected data is stored in the memory unit and may be transmitted to the smart device / network via the connectivity unit after the medicament delivery event finishes.

[0098] The sensor can be one of or the combination of the following: a mechanical switch, a Halleffect sensor, an accelerometer.

[0099] The mechanical switch, hall-effect sensor, or accelerometer can be used for detection of the insertion ofthe a needle into an injection port.

[0100] The accelerometer can be used for detecting medicament delivery events.

[0101] Possible wireless communication methods include Bluetooth and Cellular Networks.

[0102] Bluetooth connectivity requires a smart device to transmit the stored data to the network and it requires a pairing action between the pad and the smart device before being able to use the supporting pad in case of 2-way connection. But it’s a cheaper alternative and it requires less space on PCB. A 1-way connection does not require pairing.

[0103] The cellular network does not require any pairing process, it can be used as a plug-n-play device, no prior setup is needed, but it’s more expensive and it requires more space on PCB. Depending on the requirements ofthe product any of those two technologies can be used. Such processing units may comprise a logic circuit or control unit including a microprocessor, microcontroller, programmable digital signal processor or another programmable device. The processing circuitry may also, or instead, each include an application specific integrated circuit, a programmable gate array or programmable array logic, a programmable logic device, or a digital signal processor. Where the processing circuitry includes a programmable device such as the microprocessor, microcontroller or programmable digital signal processor mentioned above, the processor may further include computer executable code that controls operation ofthe programmable device.The medicament delivery devices described herein can be used for the treatment and / or prophylaxis of one or more of many different types of disorders. Exemplary disorders include, but are not limited to: rheumatoid arthritis, inflammatory bowel diseases (e.g.

[0104] Crohn’s disease and ulcerative colitis), hypercholesterolaemia, diabetes (e.g. type 2 diabetes), psoriasis, migraines, multiple sclerosis, anaemia, lupus, atopic dermatitis, asthma, nasal polyps, acute hypoglycaemia, obesity, anaphylaxis and allergies. Exemplary types of drugs that could be included in the medicament delivery devices described herein include, but are not limited to, antibodies, proteins, fusion proteins, peptibodies, polypeptides, pegylated proteins, protein fragments, protein analogues, protein variants, protein precursors, and / or protein derivatives. Exemplary drugs that could be included in the medicament delivery devices described herein include, but are not limited to (with nonlimiting examples of relevant disorders in brackets): etanercept (rheumatoid arthritis, inflammatory bowel diseases (e.g. Crohn’s disease and ulcerative colitis)), evolocumab (hypercholesterolaemia), exenatide (type 2 diabetes), secukinumab (psoriasis), erenumab (migraines), alirocumab (rheumatoid arthritis), methotrexate (amethopterin) (rheumatoid arthritis), tocilizumab (rheumatoid arthritis), interferon beta-1 a (multiple sclerosis), sumatriptan (migraines), adalimumab (rheumatoid arthritis), darbepoetin alfa (anaemia), belimumab (lupus), peginterferon beta-1 a' (multiple sclerosis), sarilumab (rheumatoid arthritis), semaglutide (type 2 diabetes, obesity), dupilumab (atopic dermatitis, asthma, nasal polyps, allergies), glucagon (acute hypoglycaemia), epinephrine (anaphylaxis), insulin (diabetes), atropine and vedolizumab (inflammatory bowel diseases (e.g. Crohn’s disease and ulcerative colitis)). Pharmaceutical formulations including, but not limited to, any drug described herein are also contemplated for use in the medicament delivery devices described herein, for example pharmaceutical formulations comprising a drug as listed herein (or a pharmaceutically acceptable salt of the drug) and a pharmaceutically acceptable carrier. Pharmaceutical formulations comprising a drug as listed herein (or a pharmaceutically acceptable salt of the drug) may include one or more other active ingredients, or may be the only active ingredient present.

[0105] The inventive concept has mainly been described above with reference to a few examples. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the inventive concept, as defined by the appended claims.

Claims

CLAIMS1. A drive assembly for a medicament delivery device (1), the drive assembly extending in a longitudinal (Y) direction extending between a proximal end and a distal end of the drive assembly, and in a transverse (X) direction being perpendicular to the longitudinal direction and comprising:a rod holder (17) having a central through-opening (17a) and a cam surface (17b), a plunger rod (19) operatively arranged to move within the through-opening of the rod holder, and comprising a cam follower (19a) configured to cooperate with the cam surface to enable rotation between the rod holder and the plunger rod,a torsion member (21) operatively arranged to, upon activation, cause rotation of the plunger rod relative to the rod holder,wherein the plunger rod or the rod holder comprises a first locking surface (27), being a transversely extending surface, as seen relative to a longitudinal axis (Ya) of the plunger rod, and the other one of the plunger rod and the rod holder comprises a second locking surface (29) abutting the first locking surface for restraining the plunger rod from movement in the proximal direction prior to activation.

2. The drive assembly according to claim 1 , wherein the first locking surface extends at an angle (a) within the range of from 10° to 90°, relative the longitudinal axis of the plunger rod, optionally 20° to 90° relative the longitudinal axis of the plunger rod.

3. The drive assembly according to claim 1 or claim 2, wherein the plunger rod or the rod holder comprises the first locking surface and the other one of the rod holder and the plunger rod comprises a protrusion (41), protruding out from the rod holder or the plunger rod in the transverse direction, wherein the protrusion comprises the second locking surface.

4. The drive assembly according to claim 3, wherein the first locking surface and the protrusion are configured to disengage from each other upon rotation between the rod holder and the plunger rod.

5. The drive assembly according to any one of the preceding claims, wherein one of the plunger rod and the rod holder has a first thread (19b) and the other one of the rod holder and the plunger rod has a thread follower (17d) configured to cooperate with the first thread and wherein the first thread and the thread follower are configured to engage to enable further rotation of the plunger rod as a result of the release of the torsion member.

6. The drive assembly according to any one of claims 1 to 5, wherein the rod holder comprises a locker thread (39) and wherein the first locking surface forms part of an end section of the locker thread and the plunger rod comprises a protrusion (41), protruding outfrom the plunger rod in the transverse direction, wherein the protrusion comprises the second locking surface.

7. The drive assembly according to claim 5 and 6, wherein the locker thread is positioned proximally, in the proximal direction of the drive assembly, relative to the first thread prior to activation.

8. The drive assembly according to any of claims 1 to 5, wherein the rod holder has a cam curve (31) including a distal cam surface (33) a proximal opposing surface (35) and a cam opening arranged between the distal cam surface and the opposing surface, wherein the follower is configured to be in contact with and move along the distal cam surface during the rotation between the rod holder and the plunger rod and wherein the proximal opposing surface forms first locking surface.

9. The drive assembly according to claim 8, wherein the proximal opposing surface of the cam curve comprises a first section (35a) and a second section (35b), the second section being positioned distally, as seen in the proximal direction of the drive assembly, relative to the first section, the first section being the first locking surface and wherein the first section extends at a first angle (a) relative the longitudinal axis of the plunger rod and the second section extends at a second angle (B) relative the longitudinal (Y) axis of the plunger rod, wherein the first angle is greater than the second angle.

10. The drive assembly according to any one of claims 1 to 5, wherein the plunger rod comprises an axial support member (19’) connected to a proximal end (43) of the plunger rod and configured to contact a stopper (15) of a medicament container (13), the axial support member being connected to the rod holder at a proximal end of the rod holder (45) prior to activation and being configured to disengage from the rod holder upon rotation between the rod holder and the plunger rod, wherein the rod holder or the axial support member comprising the first locking surface and the other one of the axial support member and the rod holder comprises the second locking surface.

11. The drive assembly according to claim 10, wherein one of the axial support member and the rod holder comprises a male part (51) and the other one a mating female part (53) configured to form a snap-fit connection with the male part.

12. The drive assembly according to claim 11 , wherein the rod holder comprises snap arms (47) provided with the male part or the female part, the snap arms being configured to hold the axial support member prior to activation and configured to be flexed radially outwardly and release the axial support member upon rotation between the rod holder and the plunger rod.

13. The drive assembly according to claim 12, wherein the snap arms comprise the male part in the form of an inwardly protruding flange and the axial support member comprises themating female part in the form of a groove configured to form a snap-fit connection with the inwardly protruding flange.

14. The drive assembly according to any one of claims 1 to 5, wherein the first locking surface is a surface of a locking ledge arranged at a proximal end of the rod holder and the plunger rod comprises a protrusion (19a), protruding out from the plunger rod in the transverse (x) direction, wherein the protrusion comprises the second locking surface.

15. The drive assembly according to any one of the preceding claims, wherein the drive assembly comprises a medicament container (13) and a stopper (15) arranged in the medicament container and wherein the plunger rod is configured to push the stopper in the proximal direction in the medicament container.

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