Drug delivery device

A drug delivery device (1) is provided comprising a housing (2), a cartridge holder (3) which is adapted and arranged for receiving a cartridge (4) for holding a plurality of doses of a drug (5), wherein the cartridge holder (3) is removable from the housing (2) to enable an exchange of the cartridge (4), a piston rod (9) adapted and arranged to be moved from an initial position towards an end position for dispensing a dose of drug (5) from the device (1) and to be moved from the end position back towards the initial position to perform a reset operation of the device (1), and at least one resilient member (20, 25). The at least one resilient member (20, 25) is in direct mechanical contact with the piston rod (9) and the resilient member (20, 25) is adapted and arranged to prevent an unintentional movement of the piston rod (9) towards the initial position due to mechanical cooperation with the piston rod (9).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. national stage application under 35 USC § 371 of International Application No. PCT/EP2015/064356, filed on Jun. 25, 2015, which claims priority to European Patent Application No. 14174641.2 filed on Jun. 27, 2014, the entire contents of which are incorporated herein by reference.

The present disclosure relates to a drug delivery device.

In a drug delivery device, often, a bung within a cartridge containing a plurality of doses of a drug is displaced by a piston rod. Thereby, a dose of the drug is expelled from the cartridge.

A drug delivery device is described in document WO 2008/058666 A1, for example.

Certain aspects of the present disclosure relate to facilitate provision of an improved drug delivery device.

One aspect relates to a drug delivery device. The device may comprise a housing. The device may further comprise a cartridge holder. The cartridge holder may be connectable, e.g. screwable, to the housing. The cartridge holder may be adapted and arranged for receiving a cartridge for holding a plurality of doses of a drug. The cartridge holder may be removable from the housing to enable an exchange of the cartridge. The device may, thus, be a reusable device. The device may further comprise the cartridge for holding a plurality of doses of a drug. The term “drug”, as used herein, preferably means a pharmaceutical formulation containing at least one pharmaceutically active compound,

Exendin-4 for example means Exendin-4(1-39), a peptide of the sequence H His-Gly-Glu-Gly-Thr-Phe-Thr-Ser-Asp-Leu-Ser-Lys-Gln-Met-Glu-Glu-Glu-Ala-Val-Arg-Leu-Phe-Ile-Glu-Trp-Leu-Lys-Asn-Gly-Gly-Pro-Ser-Ser-Gly-Ala-Pro-Pro-Pro-Ser-NH2.

or an Exendin-4 derivative of the sequence

The cartridge may be connectable, for example screwable, to the housing. Alternatively, the cartridge may be retained in the cartridge holder and the cartridge holder may be connectable to the housing. The cartridge may comprise a bung. The bung is moveably disposed in an interior of the cartridge. The device further comprises a piston rod. The piston rod is moveable with respect to the cartridge. The piston rod may be guided through the housing. The piston rod is adapted and arranged to be moved from an initial position towards an end position for dispensing a dose of the drug from the device and, in particular from the cartridge. The initial position may be that position in which the piston rod is positioned when the device is supplied from the manufacturer. For dispensing a dose, the piston rod may mechanically cooperate with the bung, thereby moving the bung with respect to the cartridge and, thus, expelling the drug from the cartridge. Preferably, the piston rod is in permanent mechanical contact with the bung when a cartridge is loaded within the device.

When the complete amount or almost the complete amount of drug was dispensed from the cartridge, the piston rod is positioned in the end position. The piston rod is adapted and arranged to be moved from the end position back towards the initial position to perform a reset operation of the device. Preferably, the piston rod is moved from the end position towards the initial position after the complete amount of drug was dispensed from the cartridge. The piston rod is moved back into the initial position to prepare the insertion of a replacement cartridge into the device.

The device further comprises at least one resilient member. The resilient member may be a spring member. The resilient member may comprise a spring arm, for example. The resilient member may be adapted and arranged to be in direct mechanical contact with the piston rod. The resilient member may abut, preferably permanently abut, the piston rod.

The at least one resilient member is adapted and arranged to prevent an unintentional movement of the piston rod towards the initial position due to mechanical cooperation with the piston rod. An unintentional movement of the piston rod towards the initial position may occur when the connectable cartridge or the cartridge holder is unintentionally partly removed, e.g. unscrewed, from the device, for example when a user tries to replace a needle assembly on the device. In other words, a movement of the piston rod is for example unintentional, when the piston rod is moved towards the initial position while the cartridge is still loaded within the device. More general, an unintentional movement of the piston rod may be any movement of the piston rod towards the initial position which is not actively triggered by the user.

Preferably, the resilient member mechanically cooperates with the piston rod such that the piston rod cannot be moved back towards the initial position without applying a minimum force against the piston rod in axial direction. In other words, the minimum required force in order to move the piston rod back towards the initial position is determined by a frictional force exerted onto the piston rod by the resilient member that mechanically cooperates with the piston rod in such way that the frictional force represents a mechanical resistance. The piston rod may not be able to move towards the initial position due to its own weight.

In this way, the piston rod always comprises a well-defined position with respect to the bung. In particular, it is prevented to bring the piston rod out of mechanical cooperation with the bung when the cartridge holder containing the cartridge is—unintentionally—partly unscrewed from the device. Only if an axial force is applied onto the piston rod, e.g. when the user intentionally pushes onto the piston rod after the cartridge holder has been detached and the cartridge has been completely removed, the piston rod becomes able to move towards the initial position. In this way, dispensing of an underdose from the cartridge, which may have fatal consequences for a user, can be prevented. Thus, provision of a safe and user-friendly device is facilitated.

According to one embodiment, the resilient member is flexible in the radial direction. The resilient member exerts a radial force, in particular a radially inwardly directed force, onto a peripheral or outer surface of the piston rod such that movement of the piston rod between the initial position and the end position is impeded. Preferably, any movement of the piston rod with respect to the cartridge may be hampered by means of the resilient member. The resilient member may slide along the piston rod when the piston rod is moved between the initial position and the end position. Preferably, the force which is exerted onto the peripheral surface of the piston rod by means of the resilient member does not result in a significant increase of the force which is required for dispensing a dose of the drug, i.e. for moving the piston rod towards the end position. The force which is applied onto the piston rod by means of the resilient member may be adjustable by adjusting an elasticity or spring force of the resilient member, a length of the resilient member, the number of resilient members and/or a diameter of the piston rod. In this way, provision of a flexibly usable drug delivery device is facilitated.

According to one embodiment, the resilient member comprises a free end-face. A free end-face may be an end-face which is not connected to or is not a part of a further component of the device. In this way, a high elasticity of the resilient member is achieved. The free end-face is shaped spoon-like. The free end-face may be rounded. The free end-face may be curved. The free end-face may comprise a convexely curved part or side-face. The free end-face may further comprise a concavely curved part or side-face. The convexely curved part and the concavely curved part may be arranged oppositely to one another. The convex part of the end-face is preferably in direct mechanical contact with the piston rod. The convex part abuts, preferably permanently abuts, the piston rod. In this way, a jamming of the resilient member and the piston rod may be prevented. In particular, it may be prevented that the resilient member gets tilted with a thread arranged on the peripheral surface of the piston rod. In this way, provision of a reliable drug delivery device is facilitated which is less prone to errors.

According to one embodiment, the device comprises two, three or more resilient members. The resilient members may be are arranged symmetrically around the piston rod. In this case the different resilient members may have an equal spring force. In this way, unintentional movement of the piston rod towards the initial position may be effectively prevented. Moreover, the resilient members help to center the piston rod within the device. Alternatively, the different resilient members may have a different spring force as compared to one another. In this case, a symmetric arrangement of the resilient members may be superfluous. Due to the different spring forces of the resilient members, the piston rod may be centered within the device and, further, unintentional movement of the piston rod towards the initial position may be prevented.

According to one embodiment, the device further comprises an interaction member. The interaction member is secured against rotation with respect to the housing. The interaction member and the housing are configured to mechanically cooperate with one another for preventing rotation of the interaction member with respect to the housing. The interaction member may be shaped ring-like. The interaction member may be resilient. The interaction member may be a spring member. The interaction member may be a multispring.

According to one embodiment, the interaction member comprises the resilient member. Preferably, the interaction member may comprise two, three or more resilient members. The resilient member and the interaction member may be integrally formed. The resilient member may be formed out of the interaction member.

According to one embodiment, the interaction member comprises an opening, preferably an inner opening. The piston rod is arranged at least partly within the opening of the interaction member. The piston rod is moveable through the opening between the initial position and the end position. In particular, the interaction member is arranged around the piston rod. The resilient member is adapted and arranged to protrude, e.g. from the interaction member, in a radial inward direction towards the piston rod. The resilient member may be adapted and arranged to protrude in the radial inward direction and into the opening as seen in plan view onto the device. In this way, an inner diameter of the opening may be diminished or reduced. In particular, an area within the device through which the piston rod is moved during operation of the device may be reduced by means of the resilient member. In particular, the resilient member is configured to reduce a diameter of the opening through which the piston rod is guided. In this way, the resilient member mechanically cooperates with the piston rod when the piston rod is moved between the initial position and the end position.

According to one embodiment, the resilient member comprises two end-faces. One endface may be in mechanical contact with the interaction member, for example. Alternatively, the end-face may be in mechanical contact with a further component of the device. In other words, this end-face may not be free. The other end-face is free from mechanical contact with the interaction member or with the further component. In other words, said end-face is the previously described free end-face. The free end-face of the resilient member protrudes into the opening of the interaction member—as seen in a plan view onto the device—for mechanically cooperating with the piston rod.

According to one embodiment, the interaction member comprises metal. The interaction member may comprise a carrier. The carrier may be shaped plate-like. The carrier may be circular or approximately circular. The carrier may comprise a shape corresponding to the shape of a diameter, in particular an inner diameter, of the drug delivery device. The carrier may comprise an inner area comprising the opening. The opening may be stamped out of the inner area of the carrier.

According to one embodiment, the resilient member is formed out of the inner area of the interaction member. The resilient member may protrude from the carrier. Thus, the number of components of the device is kept small. Accordingly, provision of a cost-effective and reliable drug delivery device is facilitated. The resilient member comprises metal. The resilient member may comprise the same metal as the interaction member.

According to one embodiment, the interaction member and, in particular, the carrier comprises at least one securing member. The carrier may comprise two, three or more securing members. With one end, the securing member may be fixed to the carrier. With another end, the securing may be free. The securing member may comprise a spring arm, for example. The resilient member and the securing member may be arranged on opposite sides of the interaction member. The interaction member may comprise a proximal side and a distal side. The distal side may be that side which is arranged closer to a dispensing end of the device. The resilient member may be arranged on the proximal side. The securing member may be arranged on the distal side.

According to one embodiment, the device further comprises a guiding member, e.g. a guide nut. The guiding member may be adapted and arranged to mechanically cooperate with the piston rod for guiding the movement of the piston rod between the initial position and the end position. Due to mechanical cooperation with the guiding member, the piston rod may perform a helical movement through the housing. The securing member may be resiliently mounted on the carrier for engaging with the guiding member. In this way, rotation of the guiding member with respect to the housing may be prevented.

According to one embodiment, the interaction member further comprises a retaining means. The retaining means may be formed as a cantilever-structure with a fixed end and a free end. The fixed end may be fixed onto the carrier. The retaining means may be formed resiliently. The retaining means may comprise a spring arm, for example. The retaining means may comprise a snap feature, e.g. a protrusion. The snap feature may be adapted and arranged for mechanically cooperating with a retaining member of the device for rotationally locking the retaining member with respect to the housing. The interaction member and the retaining member may be adapted and arranged to encompass the guiding member when assembled within the housing of the device. The retaining member may be secured against axial movement with respect to the housing due to mechanical cooperation with the housing. When the cartridge holder is not firmly connected to the housing, the retaining member may be rotatable between a first and a second position. In this way, the securing member may not engage with the guiding member that may rotate with respect to the housing and may lead to the piston rod performing helical movement towards the initial position. When the cartridge holder is firmly connected to the housing, the retaining member may be secured against rotation with respect to the housing due to mechanical cooperation with the interaction member. Consequently, the securing member may engage with the guiding member which becomes prevented from rotating with respect to the housing and the piston rod becomes prevented from moving back towards the initial position, but may be moved towards end position by dispensing.

According to one embodiment, the device further comprises an inner member. The inner member may comprise metal. The inner member may be shaped plate-like. The inner member may comprise a ring-like structure. The inner member may comprise a carrier or base plate. An opening may be provided in an inner area of the carrier. The opening may have a smaller diameter as compared to the opening of the interaction member. The piston rod may be at least partly arranged within the opening of the inner member. The inner member and the resilient member may be integrally formed. Accordingly, the resilient member can be connected or, alternatively, arranged adjacently to the interaction member without being connected to the interaction member by means of the inner member. The resilient member comprises metal. The resilient member comprises the same metal as the inner member.

The resilient member may protrude from the inner member, in particular from the carrier. The inner member and, in particular the carrier, may comprise an inner side-face. The inner side-face may be arranged oppositely to the peripheral surface of the piston rod. The inner member and, in particular the carrier, may comprise an outer side-face. The outer side-face may form an (outer) edge or side of the carrier. The inner side-face may form an (inner) edge or side of the carrier. The resilient member may protrude from the outer side-face towards the inner side-face. This may help to provide a resilient member which comprises a length which is greater than the length of the resilient member being unitarily formed with the interaction member. In this way, the elasticity of the resilient member and the end-face of the resilient member may be optimally adjusted to the size and the diameter of the piston rod.

According to one embodiment, as seen in plan view onto the device, the inner member is arranged at least partly within the opening of the interaction member. As seen in plan view, the inner member at least partly protrudes into the opening of the interaction member. In particular, the resilient member may protrude from the outer side-face and into the opening of the interaction member. In this way, the diameter of the opening of the interaction member may be reduced. The resilient member protrudes into the opening for mechanically cooperating with the piston rod.

According to one embodiment, the resilient member and, in particular the inner member, is connected to the interaction member. In other words, the resilient member and the interaction member may not be integrally formed. Rather, the inner member, which comprises the resilient member, may be engaged with the interaction member. This may help to save development costs for the device as the resilient member can be designed independently from the function of the interaction member. The inner member may be snapped into the opening of the interaction member, for example. Thus, the inner member and the interaction member may be releasably connected. Alternatively, the inner member may be laser-welded to the interaction member. Thus, the inner member and the interaction member may be non-releasably connected.

According to one embodiment, the inner member and the interaction member are arranged adjacently within the housing. The inner member and the interaction member may be arranged to abut one another. However, there may be no connection feature between the inner member and the interaction member. In this way, the resilient member can be designed independently from the function of the interaction member. In particular, a degree of freedom in the construction of the resilient member may be greater as compared to the embodiment where the inner member is connected to the interaction member. Accordingly, a length of the resilient member may be greater as compared to the embodiment where the inner member is connected to the interaction member. Also an outer diameter of the inner member, in particular the whole size, may be greater as compared to the embodiment where the inner member is connected to the interaction member.

The inner member and the interaction member may be arranged in a predetermined position with respect to one another. The predetermined position may be a predetermined rotational or angular position. For arranging the interaction member and the inner member at the predetermined position with respect to one another, an outer shape of the inner member may be equal to or at least similar to an outer shape of the interaction member. In particular, the carriers of the interaction member and the inner member may comprise the same contour or outer shape or at least a similar contour or outer shape. In particular, the interaction member and the inner member may comprise similarly or equally shaped positioning elements. The housing may comprise at least one positioning element, for example two, three or more positioning elements. The positioning element may comprise a notch or groove, for example. The positioning element may be adapted and arranged to receive the inner member and the interaction member for arranging the inner member and the interaction member in the predetermined position with respect to one another.

The inner member may also comprise at least one positioning element, for example two, three or more positioning elements. The number of positioning elements of the inner member may be equal to the number of positioning elements of the housing. The positioning elements of the inner member may be adapted and arranged to mechanically cooperate with the positioning element of the housing. The positioning element may comprise a protrusion, for example. The protrusion may protrude from the carrier of the inner member. The interaction member may comprise at least one positioning element, for example two, three or more positioning elements. The number of positioning elements of the interaction member may be equal to the number of positioning elements of the housing and of the inner member. The positioning element of the interaction member may be adapted and arranged to mechanically cooperate with the positioning element of the housing. The positioning element may comprise a protrusion, for example. The protrusion may protrude from the carrier of the interaction member. An outer shape of the positioning element of the inner member may be equal to an outer shape of the positioning element of the interaction member. The positioning elements of the inner member and the interaction member may be adapted and arranged to mechanically cooperate with the positioning element of the housing such that the inner member and the interaction member are rotationally locked with respect to the housing and with respect to one another.

The resilient member is adapted and arranged to impede the movement of the piston rod towards the initial position when the cartridge holder is only partly removed, e.g. unscrewed, from the housing, which may happen when the user replaces a needle device arranged at an end section of the cartridge holder. By means of the device and especially of the resilient member, the piston rod is kept in arrangement with the bung until the cartridge holder and, thus, the cartridge is completely removed from the device. In this way, a user-friendly and safe drug delivery device is provided.

Of course, features described above in connection with different aspects and embodiments may be combined with each other and with features described below.

Like elements, elements of the same kind and identically acting elements may be provided with the same reference numerals in the figures.

InFIGS. 1 to 3a drug delivery device1is shown. The drug delivery device1comprises a housing2. The housing2is adapted and arranged for protecting components of the device1arranged within the housing2from environmental influences.

The drug delivery device1and the housing2have a distal end6and a proximal end7. The term “distal end” designates that end of the drug delivery device1or a component thereof which is or is to be arranged closest to a dispensing end of the drug delivery device1. The term “proximal end” designates that end of the device1or a component thereof which is or is to be arranged furthest away from the dispensing end of the device1. The distal end6and the proximal end7are spaced apart from one another in the direction of an axis29. The axis29may be the longitudinal axis or rotational axis of the device1.

The drug delivery device1comprises a cartridge holder3. The cartridge holder3comprises a cartridge4. The cartridge4contains a drug5, preferably a plurality of doses of the drug5. The cartridge4is retained within the cartridge holder3. The cartridge holder3stabilizes the position of the cartridge4mechanically. The cartridge holder3is connectable, e.g. by a threaded engagement or by a bayonet coupling, to the housing2. The cartridge holder3and the housing2are releasably connected to one another. In an alternative embodiment, the cartridge4may be directly connected to the housing2. In this case, the cartridge holder3may be redundant. The drug delivery device1may be a pen-type device, in particular a pen-type injector. The device1may be a re-usable device, which means that the cartridge4can be replaced, in particular during a reset operation, by a replacement cartridge for dispensing a plurality of doses from the replacement cartridge.

A bung5is slideably retained within the cartridge4. The bung5seals the cartridge4proximally. Movement of the bung5in the distal direction with respect to the cartridge4causes the drug5to be dispensed from the cartridge4. A needle assembly (not explicitly shown in the Figures) can be arranged at the distal end section of the cartridge holder3, e.g. by means of an engagement means12, e.g. a thread. A cap17may be secured to the cartridge holder3to protect the device1and, in particular, the cartridge holder3from environmental influences, e.g. when the device1is not in use.

The device1further comprises a dose setting member14and a dose button15operated for setting and dispensing a dose of the drug5. The device1comprises a piston rod9. The piston rod9is configured to transfer movement through the housing2for expelling a dose of drug5from the cartridge4. The piston rod9is moveable between an initial position with respect to the housing2and an end position with respect to the housing2. The initial position may be the position of the piston rod9when the device1is supplied from the manufacturer. Moreover, the initial position may be the position of the piston rod9after a reset operation was performed. The initial position may be the most proximal position of the piston rod9. The end position may be the position of the piston rod9after the complete amount of the drug5was dispensed from the cartridge4. The end position may be the most distal position of the piston rod9. During operation of the device1, in particular for dispensing a dose of the drug5, the piston rod9is moved towards the end position.

The piston rod9has a distal end, which is arranged nearest to the dispensing end of the device1. The distal end section of the piston rod9comprises a bearing member11. The bearing member11is arranged between the bung8and the piston rod9. The bearing member11is configured to reduce damages that may be caused by friction. The bearing member11may be part of the piston rod9. The bearing member11may be connected to the piston rod9. Alternatively, the bearing member11and the piston rod9may be integrally formed. The bearing member11and the bung8are in mechanical contact, in particular in abutment, throughout the operation of the device. The bearing member11and the bung8are in mechanical contact as long as the cartridge4or a replacement cartridge is loaded within the device. In other words, the bearing member11and the bung8are in mechanical contact as long as the cartridge holder3is at least partly connected to the housing2, which is explained in detail in connection with the description of theFIGS. 4 to 9.

The piston rod9is configured as a lead screw. The piston rod9comprises two threaded sections10A,10B. The threaded sections10A,10B have opposite senses of rotation. A first threaded section10A is located at a distal part of the piston rod9and a threaded section10B is located at a proximal part of the piston rod9. The piston rod9and, in particular, the first threaded section10A, is in threaded engagement with a guiding member18, e.g. a guide nut. The guiding member18comprises a centered hole. Within the centered hole a screw thread is designed. The screw thread is used for being coupled to the piston rod9in order to urge the piston rod9in a predetermined helical movement through the housing2and towards the end position. The piston rod9is axially and rotationally moveable towards the end position due to mechanical cooperation with the guiding member18.

Furthermore, the piston rod9and, in particular, the second threaded section10B is in threaded engagement with a drive member13. The drive member13exerts a force onto the piston rod9to cause a movement of the piston rod9for delivering a dose of the drug5when a user pushes onto the dose button15.

The device further comprises an interaction member16. The device1further comprises a retaining member19. The interaction member16and the retaining member19encompass the guiding member18when assembled within the housing2of the device1. The interaction member16is positioned within the housing2and secured against rotational movement with respect to the housing2, e.g. by mechanical cooperation of locking or positioning elements30A,30B (seeFIG. 4) with corresponding locking or positioning elements36A,36B, e.g. notches or grooves, of the housing2(seeFIG. 13). The interaction member16is a spring member. The interaction member16may be designed as a multispring. The interaction member16is shaped ring-like or approximately ring-like. The interaction member16comprises a carrier21(seeFIG. 4). The carrier21may be shaped plate-like. The carrier21comprises an inner area26. The inner area26comprises an opening27. The opening27is stamped out of the inner area27. In an operating state of the device1, i.e. the state when the cartridge holder3holding the cartridge4is—at least partly—connected to the housing2and the device1is ready for setting and dispensing a dose, the piston rod9is led through the opening27(seeFIG. 5). In particular, the piston rod9is at least partly positioned within the opening27for being moved through the opening27during operation of the device1.

The interaction member16comprises metal. In particular, the interaction member16is formed from metal. The interaction member16comprises one, two or more securing members31. The respective securing member31is formed in the carrier21. The securing member31and the carrier21are integrally formed. The securing member31comprises a spring arm, for example. The securing member31is resiliently mounted on the carrier21for engaging with the guiding member18. At the respective free end, the securing member31comprises an edge or a hook31A for engagement with corresponding notches or interspaces18A of the guiding member18(seeFIG. 2A). Thus, the securing member31may be pivoted on its free ends with the hooks31A thereon towards the centre of the carrier21. Thus, the respective securing member31may perform a radial movement.

In the embodiment shown in the Figures, the interaction member16comprises two securing members31. The securing members31comprise an arm or cantilever arranged on opposite side-faces of the carrier21. The respective securing member31can comprise a cantilever- or leaf spring-structure with a hook, a pawl or an edge for engagement with the structure elements of the guiding member18as explained below. With one end, the respective securing member31is fixed to the carrier21and with the other end the securing member31is free. The securing member31is configured to take an engaged state in which the securing member31is engaged with the guiding member18in order to prevent rotation of the guiding member18with respect to the housing2. Moreover, the securing member31is adapted and arranged to take a disengaged state, in which the securing member31is disengaged from the guiding member18in order to allow rotation of the guiding member18. The retaining member19may be rotatable relative to the housing2for interaction with the securing member31in order to change between the engaged state and the disengaged state of the securing member31as described later on in more detail.

Due to mechanical cooperation with the interaction member16, and in particular, the securing members31, the guiding member18is secured against rotational movement with respect to the housing2when the cartridge holder3is firmly connected to the housing2, which is explained later in more detail. This means that, as long as the cartridge holder3is firmly connected to the housing2, i.e. it is not partly unscrewed from the housing2, the guiding member18is not rotatable and, hence, mechanical cooperation between the guiding member18and the piston rod9prevents movement of the piston rod9towards the initial position. Thus, when the cartridge holder3is firmly connected to the housing2, unintentional movement of the piston rod9towards the initial position is prevented due to mechanical cooperation with the guiding member18.

The retaining member19is a ring-shaped member. The retaining member19comprises one or more radial recesses. The securing members31may be circumferentially arranged on at least a part of the exterior of the interaction member19. The securing members31may pass the radial recesses of the retaining member19in order to engage with the guiding member18. Preferably, the securing members31may be resilient or resiliently mounted such that they are tensioned in radial direction towards the longitudinal axis of the device1. This has the effect that during the disengaged state of the securing members31, the retaining member19holds the securing members31out of engagement with the guiding member18, whereby for switching into the engaged state of the securing members31, the retaining member19releases the securing members31such that the securing members31may be urged to pass the recesses of the retaining member19caused by spring forces and may engage with the guiding member18.

Moreover, the retaining member19provides a ramp-shaped exterior surface (not explicitly shown in the Figures) providing two ramps arranged at opposite sides of the exterior of the retaining member19. The ramps are angled ramps providing a transition from a broader diameter to a narrowed diameter of the exterior of the retaining member19. The ramps are arranged substantially at the positions of the corresponding radial recesses. The ramps are designed in order to enable the securing member31to slide along the exterior surface of the retaining member19from the broader part to the narrowed part and to perform a radial movement towards the center of the retaining member19when reaching the narrowed diameter of the retaining member19.

In one embodiment (seeFIG. 2A), the securing members31can provide protrusions38which are molded on the cantilever-formed securing members31and which are directed towards the centre of the carrier21. The protrusions38are designed for sliding along the ramps on the exterior of the retaining member19.

A second embodiment (seeFIG. 2B) differs from the first embodiment in that the free ends of the cantilever-formed securing members31are bent such that an edge is provided forming protrusions39for engagement with a part of the retaining member19in order to actuate the securing members31. Moreover, the respective free ends of the cantilever-formed securing members31provide a sinusoidal shape with at least two reverse loops40A and40B, wherein a first loop40A is molded towards the axis of the device1and forms the hook, edge or pawl31A for engagement with the guiding member18and wherein a second loop40B is molded away from the axis of the device1and finishes in the free end of the securing member31. The second loop40B is designed to at least partially contact with a part of the retaining member19in the engaged state of the securing members31, i.e. when the securing members31are actuated by the retaining member19and engage with the guiding member18. In particular, in the engaged state, the second loop40B may be tangentially arranged with respect to a corresponding part of the retaining member19, thereby providing for a smooth contact with the retaining member19. This embodiment may provide for a save engagement and contact between the securing members31and the retaining member19without the risk of any damage of the retaining member19due to scratching of a sharp edge of a free end of the securing members31on the retaining member19during torsional moments.

A third embodiment (seeFIG. 2C) differs from the first and second embodiments in that the securing members31with their cantilevers are arranged such that the interaction of the retaining member19and the securing members31works in opposite manner according to the principle of the embodiments ofFIGS. 2A and 2B. That means the resilient securing members31are tensioned in radial direction away from the axis of the carrier21such that spring forces may urge the securing members31away from the axis of the assembly for disengagement from the guiding member18. That means, the retaining member19may engage with the securing members31in order to urge the securing members31in radial direction towards the axis and into engagement with the guiding member18oppositely to the spring forces of the tensioned securing members31. On the contrary, when the securing members31are to be brought in the disengaged state, the retaining member19may release the securing members31such that the securing members31are urged in radial direction away from the center axis of the device due to the spring forces of the securing members31.

The retaining member19is secured against axial movement with respect to the housing2due to mechanical cooperation with the housing2. When the cartridge holder3is not firmly connected to the housing2, the retaining member19is rotatable between a first and a second position. When the cartridge holder3is firmly connected to the housing2, the retaining member19is secured against rotation with respect to the housing2due to mechanical cooperation with the interaction member16. For this purpose, the retaining member19comprises a snap feature19A. The snap feature19A may comprise a protrusion. The snap feature19A may be shaped wedge-like.

The interaction member16comprises a retaining means23A. The retaining means23A is formed as a cantilever-structure with a fixed end and a free end. The retaining means23A is formed resiliently. The retaining means23A comprises a spring arm. The fixed end of the retaining means23A is fixed on the carrier21. The fixed end of the retaining means23A protrudes from the carrier21. The free end points substantially in a tangential direction with respect to the carrier21. The retaining means23A comprises a snap feature23(seeFIG. 4), e.g. a protrusion. The snap feature19A of the retaining member19is configured to interact with the corresponding snap feature23of the interaction member16for rotationally locking the retaining member19with respect to the housing2in the locked state of the device1.

The retaining member19further comprises a coupling member19B. The coupling member19B comprises protrusions protruding in the distal direction from the retaining member19. The coupling member19B is provided for interaction and engagement with a corresponding coupling member (not explicitly shown) of the cartridge holder3. When the coupling members mechanically cooperate, the retaining member19is rotationally locked to the cartridge holder3. The retaining member19can be operated, e.g. rotated, by mechanical cooperation of the coupling members. The retaining member19is rotatable during a mounting and unmounting movement of the cartridge holder3, when said cartridge holder3is assembled to or at least partly detached from the housing2.

When the cartridge holder3is rotated for being released from the device1, the securing member31is brought out of mechanical cooperation with the guiding member18due to the previously described interaction with the retaining member19. This allows the guiding member18to be rotated with respect to the interaction member16. When the guiding member18is allowed to rotate with respect to the housing2, the piston rod9is moveable towards the initial position for performing the reset operation. In other words, axial movement of the piston rod9in the proximal direction into the initial position is possible when the guiding member18is free to rotate relatively to the housing2, thus enabling a helical movement of the guiding member18with respect to the piston rod9irrespective of the position and movement of the piston rod9with respect to the housing2.

In conventional devices, it can happen that, when the user replaces the needle assembly attached to the distal end section of the cartridge holder3, he or she also unintentionally moves, in particular rotates, the cartridge holder3with respect to the housing2. Thus, the cartridge holder3is rotated without having the intention to remove the cartridge holder3and, thus, the cartridge4from the device1. Movement of the cartridge holder3, however, results in the guiding member18being brought out of engagement with the interaction member16. Thus, the guiding member18is rotatable with respect to the housing and the piston rod9is unintentionally, e.g. due to gravitational force, moveable in the proximal direction towards the initial position although one or more doses of the drug5are still present in the cartridge4.

Such a movement of the piston rod9must be prevented as it causes the bearing member11to be brought out of abutment with the bung8. If the user then tries to set and deliver a further dose of the drug5, he may deliver an underdose as the piston rod9must be brought into abutment with the bung8before the piston rod9can shift the bung8distally for dispensing the dose. Thus, it is crucial that the piston rod9is kept in abutment with the bung8throughout the use of the device1and, in particular, in the case when the user unintentionally rotates the cartridge holder3with respect to the housing2, thereby partly unscrewing the cartridge holder3from the housing2. For preventing an unintentional movement of the piston rod9with respect to the housing2towards the initial position, the device1comprises at least one resilient member20,25,35as shown inFIG. 8. The resilient member20,25,35is adapted and arranged for mechanically cooperating with the piston rod9, particularly with the first threaded section10A of the piston rod9, for preventing said unintentional movement.

FIG. 4shows a three-dimensional view of a part of the drug delivery device ofFIG. 1according to a first embodiment.FIG. 5shows a three-dimensional view of parts of the drug delivery device ofFIG. 1according to the first embodiment.

InFIG. 4two resilient members20are shown. However, the device1may comprise more than two resilient members20, e.g. three, four or five resilient members20. Alternatively, the device1may comprise only one resilient member20. In this embodiment, the resilient member20is part of the interaction member16. The resilient member20is firmly connected to the interaction member16. In particular, the resilient member20and the interaction member16are integrally formed. The resilient member20is formed out of the inner area26of the carrier21of the interaction member16. The respective resilient member20protrudes from the interaction member16in a radial inward direction into the opening27. The resilient member20, thus, reduces an inner diameter of the opening27. In particular, the resilient member20protrudes from an inner side-face22of the interaction member16in the radial inward direction. The inner side-face22delimits the opening27of the interaction member16. The resilient members20and the previously mentioned securing members31are arranged at opposite sides of the carrier21as shown inFIG. 4. In particular, the securing members31are arranged at a distal face of the carrier21. The resilient members20are arranged at a proximal face of the carrier21.

The resilient members20are configured to exert a force, in particular a radial force, onto the piston rod9. The respective resilient member20comprises a length and a shape such that the resilient member20can directly mechanically cooperate with the piston rod9and, in particular with the first threaded section10A. The resilient member20is pre-tensioned towards the piston rod9. The resilient members20each comprise a spring arm or cantilever which are arranged on opposite sides of the carrier21. The resilient members20can be arranged symmetrically around the piston rod9when the piston rod9is led through the opening27(seeFIG. 5). In this case, the different resilient members20may have an equal spring force, respectively. Alternatively, the different resilient members20can have a different spring force as compared to one another. In this case, the resilient members20are not necessarily arranged symmetrically around the piston rod9as long as the piston rod9is centered in the opening27due to the different spring forces of the resilient members20.

The respective resilient member20comprises two end-faces28A,28B. With one end-face28B, the respective resilient member20is fixed to the carrier21. In other words, the end-face28B is a non-free end-face. The other end-face28A of the resilient member20is free from mechanical cooperation with the interaction member16. Accordingly, this end-face28A is a free end-face. The free end-face28A protrudes into the opening27. The resilient members20are resiliently mounted on the carrier21. Thus, the resilient members20are pivotable on their free end-faces28towards the centre of the opening27. Thus, the resilient members20may perform a radial movement.

The free end-face28A is shaped spoon-like. The free end-face28A is curved. In particular, it comprises a convexely and a concavely curved side-face33,34. The convex side-face33is in direct mechanical contact with the piston rod9. In particular, it abuts the piston rod9. When the piston rod9is moved during the operation and during the reset of the device1, the piston rod9slides along the free end-face28A, in particular along the convex side-face33. Thereby a radially inwardly directed force is exerted onto the piston rod9. Due to mechanical cooperation with the resilient member20, movement of the piston rod9between the initial position and the end position is impeded. In other words, the respective resilient member20mechanically cooperates with the piston rod9such that the piston rod9is moveable only by exceeding a resistance, in particular by exceeding a frictional force exterted onto the piston rod9by means of the resilient member20. In this way, an unintentional movement of the piston rod9towards the initial position as described above can be prevented. Thus, as long as the cartridge4is loaded within the device1, the piston rod9is always kept in abutment with the bung8by means of the resilient member20even if the user accidentally partly unscrews the cartridge holder3from the housing2.

Even if the cartridge holder3and, thus, the cartridge4is completely removed from the device1, the resilient member20keeps the piston rod9in the end position until the user actively pushes the piston rod9proximally and into the initial position, i.e. until the user intentionally resets the device1. Afterwards, the cartridge holder3holding a replacement cartridge can be screwed to the housing2.

FIG. 6shows a three-dimensional view of a part of the drug delivery device ofFIG. 1according to a second embodiment.FIG. 7shows a three-dimensional view of a part of the drug delivery device ofFIG. 1according to the second embodiment.FIG. 9shows a three-dimensional view of parts of the drug delivery device ofFIG. 1according to the second embodiment.

InFIG. 6two resilient members25are shown. However, the device1may comprise more than two resilient members25, e.g. three, four or five resilient members25. Alternatively, the device1may comprise only one resilient member25. With regard to the general features of the resilient members25, e.g. the shape (for example, the end-faces28A,28B) and the function, it is referred to the description of the first embodiment (FIGS. 4 and 5). In contrast to the resilient member20of the first embodiment, the resilient member25shown inFIGS. 6, 7 and 9is not integrally formed with the interaction member16. Rather, in this embodiment, the resilient member25is connected to the interaction member16, which is described below in detail.

In this embodiment an inner member24is provided. The inner member24is connected, preferably unreleasably connected, to the interaction member16. The inner member24is laser-welded to the interaction member16, for example. Alternatively, the inner member24may be snapped to the interaction member16. In this case, the connection between the inner member24and the interaction member16may be releasable. The inner member24comprises metal. The inner member24comprises a carrier or base plate24C. The inner member24is shaped ring-like. In other words, the inner member24comprises an opening arranged within an inner area of the carrier24C. The opening may be stamped out of the inner area. The opening may have a smaller diameter as compared to the diameter of the opening27of the interaction member16. When the device1is in an assembled state, the piston rod9is at least partly arranged within the opening of the inner member24(seeFIG. 9). According to this embodiment, the inner member24is arranged within the opening27of the interaction member16. The inner member24may comprise a connecting element24D, e.g. one or more protrusions. The connecting element24D is adapted and arranged to firmly connect the inner member24to the opening27, in particular an inner surface of the opening27which is arranged oppositely to the piston rod9, of the interaction member16. The connecting element24D is, for example, laser welded to the inner surface of the opening27. Thus, the inner member24reduces the diameter of the opening27.

The respective resilient member25is arranged at the inner member24. The inner member24and the resilient members25are integrally formed. The inner member24comprises an inner side-face24A and an outer side-face24B. The inner side-face24A forms an inner face of the carrier24C. The outer side-face24B forms an outer face of the carrier24C. The inner side-face24A delimits the opening of the inner member24, as shown inFIGS. 6 and 7. The resilient member25is arranged at the outer side-face24B. The resilient member25protrudes from the outer side-face24B in the radial inward direction. In an alternative embodiment (not explicitly shown in the Figures), the resilient member25can also protrude from the inner side-face24A in the radial inward direction.

The resilient member25protrudes into the opening27of the interaction member16for mechanically cooperating with the piston rod9. When the resilient member25mechanically cooperates with the piston rod9, it exerts a radially inwardly directed force onto the piston rod9, thus impeding the movement of the piston rod9between the initial position and the end position as described above.

FIGS. 10 and 11show a three-dimensional view of a part of the drug delivery device1ofFIG. 1according to a third embodiment.FIGS. 12 and 13shows a three-dimensional view of a part of the drug delivery device1ofFIG. 1according to the third embodiment.

InFIGS. 10 and 11two resilient members35are shown. However, the device1may comprise more than two resilient members35, e.g. three, four or five resilient members35. With regard to the general features of the resilient members35, e.g. the shape (for example the end-faces28A,28B) and the function, it is referred to the description of the first embodiment (FIGS. 4 and 5).

Also in this embodiment, the respective resilient member35is arranged at the previously described inner member24. The inner member24and the resilient members35are integrally formed as described above. The inner member24comprises the previously mentioned inner side-face24A and the outer side-face24B which delimit the carrier24C of the inner member24.

The respective resilient member35is arranged at the outer side-face24B. The resilient member35protrudes from the outer side-face24B in the radial inward direction (see, in particular,FIG. 11). In an alternative embodiment (not explicitly shown in the Figures), the resilient member35can also protrude from the inner side-face24A in the radial inward direction and, thus, towards the piston rod9.

In contrast to the resilient member20of the first embodiment, the resilient member35shown inFIGS. 10 to 13is, accordingly, not integrally formed with the interaction member16(seeFIG. 11). Further, in contrast to the resilient member25of the second embodiment, this resilient member35is also not connected to the interaction member16(seeFIG. 10). In particular, the inner member24, which comprises the resilient members35, is not connected to the interaction member16. Rather, the inner member24and the interaction member16and, thus, the resilient members35and the interaction member16, are separate components of the device1, which are not connected to one another but which are only adapted to be positioned adjacently with respect to one another within the housing2.

The inner member24is arranged more proximal with respect to the housing2than the interaction member16(seeFIGS. 12 and 13). The interaction member16and the inner member24are arranged within the housing2such that they mechanically cooperate with one another. In particular, they abut one another when positioned within the housing2. The interaction member16and the inner member24are arranged and/or fixed within the housing2at a predetermined position with respect to one another within the housing2of the device1. For this purpose, the carrier24C of the inner member24may have a greater outer diameter as compared to the carrier24C of the inner member24of the second embodiment. In particular, the carrier24C may have an outer diameter which is similar or equal to the outer diameter of the carrier21of the interaction member16. The carriers21,24C may have an equal or at least similar contour or outer shape. In particular, the carriers21,24C may comprise equally shaped positioning elements30A,30B,37D,37B. Due to mechanical cooperation of the carriers21,24C and the housing2, the inner member24and the interaction member16are arranged in the predetermined position with respect to one another.

The carrier21of the interaction member16comprises the previously mentioned positioning elements30A,30B (seeFIG. 13). The positioning elements30A,30B are arranged on opposite side-faces of the carrier21. A first positioning element30A may comprise a smaller width as compared to a second positioning element30B. In this case, the term “width” denotes an extension of the positioning elements30A,30B in a direction perpendicular to the longitudinal axis of the device1. According to a further embodiment (not explicitly shown in the figures), the carrier21may comprise only one positioning element or more than two positioning elements, e.g. three, four or more positioning elements. The positioning elements30A,30B each comprise an edge or a protrusion protruding from the carrier21in the radial outward direction. The carrier24C of the inner member24comprises two positioning elements37A,37B (seeFIG. 13). The positioning elements37A,37B are arranged on opposite side-faces of the carrier24C. A first positioning element37A may comprise a smaller width as compared to a second positioning element37B. According to a further embodiment (not explicitly shown in the figures), the carrier24C may comprise only one positioning element or more than two positioning elements, e.g. three, four or more positioning elements. The positioning elements37A,37B each comprise an edge or a protrusion protruding from the carrier24C in the radial outward direction.

The positioning elements30A,30B of the interaction member16and the positioning elements37A,37B of the inner member24are equally shaped. In particular, the first positioning elements30A,37A comprise a similar or equal shape and outer dimension, in particular width, as compared to one another and the second positioning elements30B,37B comprise a similar or equal shape and outer dimension, in particular width, as compared to one another.

The positioning elements30A,30B,37A,37B are configured to mechanically cooperate with corresponding positioning elements36A,36B of the housing2(seeFIG. 13). The positioning elements36A,36B of the housing2are arranged on an inner surface of the housing2. The positioning elements36A,36B may comprise a notch or groove, respectively. The notch or groove extends at least partly along the inner surface of the housing2. A first positioning element36A may comprise a smaller width than a second positioning element36B. The first positioning element36A may be adapted and arranged to receive the first positioning element30A,37A of the interaction member16and of the inner member24. The second positioning element36B may be adapted and arranged to receive the second positioning element30B,37B of the interaction member16and of the inner member24.

When the device1is assembled, the inner member24is rotationally positioned with respect to the housing2such that the first positioning element36A of the housing2receives the first positioning element37A of the inner member24and such that the second positioning element36B of the housing2receives the second positioning element37B of the inner member24. Then, the inner member24is introduced into the housing2. Thereby, the first positioning elements36A,37A mechanically cooperate with one another and the second positioning elements36B,37B mechanically cooperate with one another. In particular, the inner member24is guided within the housing2due to mechanical cooperation of the positioning elements36A,36B,37A,37B. Afterwards, the interaction member16is rotationally positioned with respect to the housing2such that the first positioning element36A of the housing2receives the first positioning element30A of the interaction member16and such that the second positioning element36B of the housing2receives the second positioning element30B of the interaction member16. Then, the interaction member16is introduced into the housing2such that the interaction member16is arranged adjacently with respect to the inner member24. Mechanical cooperation of the positioning elements30A,30B,36A,36B,37A,37B rotationally locks the inner member24with respect to the housing2and the interaction member16with respect to the housing2. Further, due to mechanical cooperation of the positioning elements30A,30B,36A,36B,37A,37B the inner member24and the interaction member16are arranged in a predetermined, in particular rotational, position with respect to one another. Accordingly, movement of the inner member24and, thus, of the resilient member35, with respect to the interaction member16is prevented although the inner member24is not connected to the interaction member16.

Once the interaction member16and the inner member24are arranged in the predetermined position, the resilient members35protrude into the opening27of the interaction member16—as seen in plan view onto the device—for mechanically cooperating with the piston rod9(seeFIGS. 10, 12 and 13). In other words, the inner member24and, in particular the resilient members35, diminish an inner diameter of the opening27as seen in plan view onto the device1although, in this embodiment, the inner member24is not arranged within the opening27of the interaction member16. In particular, the area within the housing2through which the piston rod9is moved during operation of the device1is reduced by means of the resilient members35. When the respective resilient member35mechanically cooperates with the piston rod9, it exerts a radially inwardly directed force onto the piston rod9, thus impeding the movement of the piston rod9between the initial position and the end position as described above.

Other implementations are within the scope of the following claims. Elements of different implementations may be combined to form implementations not specifically described herein.

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