Injection device and dose limiting mechanism

Abstract

The present disclosure relates to a dose limiting mechanism (100) for an injection device (1), the dose limiting mechanism (100) being configured to be arranged inside a housing (3) of the injection device (1) and being operable to limit a total number of doses dispensable by the injection device, the dose limiting mechanism (100) comprising: - a first elongated member (110) extending in a longitudinal direction and comprising a first profile structure (112), - a second elongated member (120) coaxial or parallel to the first elongated member (110) and comprising a second profile structure (122) facing the first profile structure (112), - a dose limiter (130) arranged between the first elongated member (110) and the second elongated member (120), the dose limiter (130) comprising a first profile section (131) and a second profile section (132), - wherein the first profile section (131) is engageable with the first profile structure (112) to transmit a longitudinal movement of the first elongated member (110) to the dose limiter (130) when the first elongated member (110) is longitudinally moved in a distal direction relative to the second member (120) during dose dispensing, and - wherein the second profile section (132) is engageable with the second profile structure (122) to maintain a longitudinal position of the dose limiter (130) relative to the second member (120) when the first member (110) is longitudinally moved in a proximal direction relative to the second member (120).

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to an injection device, such as a drug delivery device for automatic spring driven injection of a liquid medicament, i.e. a dose, which the user can set to a single size. The present disclosure further relates to a dose limiting mechanism for such an injection device. BACKGROUND

[0002] Drug delivery devices are suitable for routine injection by persons without formal medical training. This can be increasingly common among patients suffering from diabetes for whom self-treatment enables those patients to effectively manage their disease. In practice, such drug delivery devices allow the user to individually select and dispense a number of user variable doses of medicament. The present disclosure therefore does not relate to so-called fixed dose devices which only allow dispensing of a predetermined dose without the possibility to increase or decrease the set dose.

[0003] Basically, there are two types of drug delivery devices: resettable devices, i.e. reusable, and non-resettable, i.e. disposable. For example, disposable drug delivery devices are supplied as self-contained devices. Such stand-alone devices do not have a removable pre-filled cartridge. Rather, the pre-filled cartridge is not removable and replaceable from these devices without destroying the device itself. Therefore, such disposable devices do not need to have a resettable dose setting mechanism. The present invention is generally applicable for both types of devices, i.e. disposable devices as well as reusable devices.

[0004] Further differentiation of drug delivery device types involves the drive mechanism: there are devices that are manually driven (e.g. by the user applying force to an injection button), devices that are driven by a spring or the like, and devices that combine both concepts, i.e. spring-assisted devices that still require the user to apply injection force. Spring-type devices include pre-loaded springs and springs that are loaded by the user during dose selection. Some energy storage devices use a combination of spring pre-load and additional energy provided by the user, e.g. during dose setting. Other types of energy storage can include compressed fluids or electrically driven devices with batteries or the like. Although many aspects of the present disclosure can be applicable to all these types of devices, i.e. to devices with or without a drive spring or similar energy store. These types of delivery devices typically comprise three main elements: a cartridge section comprising a cartridge, usually housed within a housing or body or holder, a needle assembly connected to one end of the cartridge section, and an administration section connected to the other end of the cartridge section. The cartridge (often referred to as an ampoule) typically comprises a reservoir filled with a medicinal product, a movable rubber-type bung or stopper at one end of the cartridge reservoir, and a top with a pierceable rubber seal at the other end, usually the necked-down end. A crimped annular metal band is typically used to hold the rubber seal in place. While the cartridge housing can typically be made of plastic, the cartridge reservoir has historically been made of glass.

[0005] The needle assembly is typically a replaceable double-ended needle assembly. Prior to injection, the replaceable double-ended needle assembly is attached to one end of the cartridge assembly, a dose is set, and then the set dose is administered. This removable needle assembly can be screwed or pushed (i.e. snapped) onto the pierceable seal end of the cartridge assembly.

[0006] The administration section or dose setting mechanism is typically part of the device for setting (selecting) a dose. During injection, a lead screw, plunger or piston rod contained within the dose setting mechanism presses against the bung or stopper or plunger of the cartridge. This force causes the medicinal product contained within the cartridge to be injected through the attached needle assembly. After injection, the needle assembly is removed and discarded, as is generally recommended by most drug delivery device and / or needle assembly manufacturers and suppliers.

[0007] The administration section of a drug delivery device for selecting and dispensing a plurality of user variable doses of a medicament typically comprises a display for indicating the selected dose to the user. This is particularly important in cases where the user can select different doses each time depending on the health condition. There are mechanical displays, such as a barrel with numbers printed on its outer surface, wherein the number corresponding to the actually selected dose is visible through a window or opening in the device. While such mechanical displays are simple and reliable, they typically require a relatively large structural space, which makes the device bulky.

[0008] Pharmaceutical delivery devices or injection devices for setting a dose of variable size and for subsequently injecting or dispensing such dose can also be equipped with a so-called last dose limiting mechanism. A last dose limiting mechanism typically records the total amount of medicament dispensed from a medicament container or cartridge. A last dose limiting mechanism is typically used to prevent a set dose from exceeding the remaining amount of medicament provided in a medicament container or cartridge.

[0009] Some medicaments and thus some medicament treatment regimes require regular injections of a liquid medicament. Since the amount of medicament provided in a medicament container or cartridge is typically sufficient for multiple injections over a longer time interval, it should be ensured that once the shelf life of a medicament has passed, the medicament can no longer be injected.

[0010] For some medicaments, the medicament container and thus the medicament located therein should be used up within a predetermined time interval after the first use of the medicament. For example, the service life of a cartridge should not exceed a predefined time interval, e.g. a few days or weeks.

[0011] Furthermore, since the dose of a medicament should be dispensed or injected regularly, e.g. once or twice a day, it should be ensured that a user regularly using an injection device does not artificially or inappropriately extend the service life of a medicament container or cartridge.

[0012] It is therefore desirable to provide an injection device with a dose limiting mechanism operable to limit the total number of doses dispensable by the injection device. It is a further object to provide a dose limiting mechanism operable to limit the total number of doses dispensable by the injection device and suitable for a variety of injection devices. The injection device should provide the setting and dispensing of variable doses (and thus doses of a size settable by a user).

[0013] The dose limiting mechanism and the injection device should provide the functionality of preventing the setting and / or dispensing of a dose of medicament after a predetermined number of dose dispensing procedures has been performed. The dose limiting mechanism and the injection device should provide a limitation of the total number of doses dispensable or injectable by the injection device irrespective of the total amount of medicament dispensed or injected by consecutive dose dispensing procedures. SUMMARY

[0014] In one aspect, a dose limiting mechanism for an injection device, such as a pen-type injector, is provided. The dose limiting mechanism is configured to be arranged inside a housing of the injection device. The dose limiting mechanism is operable to limit the total number of doses dispensable or injectable by the injection device. The dose limiting mechanism comprises a first elongated component extending in a longitudinal direction and comprising a first profile structure. The dose limiting mechanism further comprises a second elongated component coaxial or parallel to the first elongated component. The second elongated component comprises a second profile structure facing the first profile structure.

[0015] The dose limiting mechanism further comprises a dose limiter arranged between the first elongated member and the second elongated member. The dose limiter comprises a first profile section and a second profile section. The first profile section is engageable with the first profile structure to transfer longitudinal movement of the first elongated member to the dose limiter when the first elongated member is longitudinally moved in a distal direction relative to the second member during or for dispensing of a dose.

[0016] The second profile section of the dose limiter is engageable with the second profile structure of the second elongated member to maintain the longitudinal position of the dose limiter relative to the second member when the first member is longitudinally moved in a proximal direction relative to the second member.

[0017] In this way, the dose limiter is operable to follow the pointing longitudinal and distal displacement of the first elongated member relative to the second elongated member. In case the first elongated member is longitudinally displaced in an opposite direction, thus along the proximal direction, the dose limiter is maintained by the second longitudinal member.

[0018] Generally, when implemented in an injection device, the first elongated member is displaced in a distal direction relative to the second elongated member when a dose dispensing action is triggered, i.e. when a trigger of the injection device is pressed by a user. When the trigger of the injection device is released, e.g. at the end of a dose dispensing or dose injection procedure, the first elongated member can be moved in an opposite direction, thus in a proximal direction. This proximally pointing movement can be induced or caused by a spring element.

[0019] In a typical configuration, the first elongated member is longitudinally moved back and forth relative to the second elongated member during or for dispensing of a medicament dose. For some examples, the first elongated member is moved in a distal direction relative to the second elongated member at the beginning of a dose dispensing action, and the first elongated member is longitudinally displaced in a proximal direction relative to the second elongated member when the dose dispensing action is interrupted or when the dose dispensing procedure is terminated.

[0020] The first profile structure of the first elongated member is engageable with the first profile section of the dose limiter such that a distally pointing longitudinal displacement of the first elongated member is equally or unalterably transferred to the dose limiter when the first elongated member is moved in a distal direction relative to the second elongated member.

[0021] In the opposite movement direction, thus when the first elongated member is subjected to proximally directed movement relative to the second elongated member, the mutual engagement of the first profile structure with the first profile section causes the first profile structure to be allowed to move proximally relative to the first profile section. In this way, the first elongated member is allowed to move in a proximal direction relative to the dose limiter.

[0022] To this end, the dose limiter is operably engaged with the second profile structure of the second elongated member by a second profile section. In other words, the mutual engagement of the second profile structure of the second elongated member with the second profile section of the dose limiter causes the dose limiter to always be allowed to move in a distal direction relative to the second elongated member but be hindered from proximally moving relative to the second elongated member.

[0023] The mutual engagement between the first profile section of the dose limiter and the first profile structure of the first elongated member supports and enables proximally directed movement of the first elongated member relative to the dose limiter but is operable to prevent distally directed movement of the first elongated member relative to the dose limiter. When the first elongated member is subjected to distally directed movement relative to the second elongated member, the dose limiter has to follow this distally directed movement.

[0024] Generally, the first elongated member is movable relative to the second elongated member and / or relative to the housing of the injection device along the distal direction from a first longitudinal position, e.g. an initial position, to a second longitudinal position, e.g. a triggered position. When the second longitudinal position is reached, the dose limiter, which has also been moved from a first longitudinal position into a second longitudinal position, is longitudinally secured to the second elongated member at least in terms of proximally directed displacement. Since the first elongated member is supposed to be subjected to a return movement from the second longitudinal position along the proximal direction towards and into the first longitudinal position, the second profile section of the dose limiter is longitudinally engaged with the second profile structure of the second elongated member such that the dose limiter is longitudinally held at the second elongated member.

[0025] According to a further example, the first profile structure comprises a regularly shaped profile structure extending along the longitudinal direction. The same applies to the second profile structure. Also, the second profile structure extends along the longitudinal direction and comprises a regular profile as seen in longitudinal direction.

[0026] According to a further example, each time the first elongated member is subjected to a distally directed longitudinal movement from the first position towards and into the second position, the dose limiter is correspondingly moved in distal direction. Typically, the longitudinal distance between the first longitudinal position of the first elongated member and the second longitudinal position defines a step size. Each time the first elongated member is subjected to a distally directed movement from the first longitudinal position towards and into the second longitudinal position, the dose limiter is moved distally by the step size.

[0027] During a return movement of the first elongated member in opposite direction relative to the second elongated member, the dose limiter remains and / or is held in longitudinal direction with and / or by the second longitudinal member. With subsequent and distally directed longitudinal displacement of the first elongated member relative to the second elongated member from the first longitudinal position towards and into the second longitudinal position, the dose limiter is again subjected to a further distally directed movement according to the step size. Typically, with each distally directed longitudinal movement of the first elongated member relative to the second elongated member, the dose limiter is subjected to a well-defined stepwise and discontinuous longitudinal displacement in distal direction.

[0028] For some examples, when the first elongated member is longitudinally engaged with a trigger of the injection device and when the second elongated member is longitudinally held to the housing of the injection device, each time the trigger of the injection device is pressed, the dose limiter is subjected to a stepwise distally directed movement relative to the second elongated member and thus relative to the housing. In this way, the longitudinal position of the dose limiter relative to the second elongated member or relative to the housing directly indicates the total number of dispense actions that have been performed by the injection device.

[0029] For some examples, an end stop is provided on one of the first elongated member, the second elongated member or on the housing of the injection device. The end stop is configured to engage with the dose limiter. When the dose limiter is in an engaged configuration with the end stop, the dose limiter and / or the first elongated member is at least one of longitudinally held or rotationally held relative to the second elongated member and / or relative to the housing. For some examples, when the dose limiter is in an engaged configuration with the end stop, the movability of the second elongated member, e.g. the rotation of the second elongated member relative to the first elongated member and / or relative to the housing, will be blocked.

[0030] Thus, when in the blocked configuration with the dose limiter engaged with the end stop, setting a dose and / or dispensing a dose with the injection device will no longer be possible.

[0031] According to a further example, the first profile structure comprises a plurality of stop faces arranged continuously in the longitudinal direction and facing the distal direction. The stop faces of the first profile structure are configured to longitudinally engage or longitudinally abut the first profile section of the dose limiter. In this way, when a stop face of the first profile structure longitudinally or axially abuts or engages the first profile section of the dose limiter, a longitudinal and distally directed displacement of the first elongated member relative to the second elongated member is transferred to the dose limiter.

[0032] The first profile structure comprises a plurality of regular, e.g. equidistantly arranged stop faces along the longitudinal direction. Typically, the consecutive or adjacently positioned stop faces are separated by a longitudinal distance according to a step length defined by the longitudinal distance between the first longitudinal position and the second longitudinal position, wherein the first elongated member is in an initial position and the first elongated member is in the triggered position.

[0033] Typically, the number of stop faces is associated with or defines the total number of doses that can be dispensed by the injection device. Before the injection device is used for the first time, a first stop face of the first profile structure can longitudinally abut or longitudinally engage the first profile section of the dose limiter.

[0034] During dose dispensing, as the first elongated member performs a distally directed movement from the first longitudinal position towards and into the second longitudinal position, the dose limiter is displaced or moved in the distal direction by a predefined step length. When the first elongated member performs a proximally directed return movement, at least when the first elongated member returns and reaches the first longitudinal position or initial position, e.g. at the end of a dose injection procedure, thus when the trigger of the injection device is released, a second stop face of the profile structure can engage or align with the first profile section of the dose limiter.

[0035] Now and in subsequent dose dispensing procedures, it will be this second stop face of the profile structure that is used to further drag or move the dose limiter in the distal direction by a predefined step length. After a second dose dispensing action, the first elongated member again performs a proximally directed return movement. At the end of this second return movement, a third stop face of the first profile structure longitudinally engages or aligns with the first profile section of the dose limiter.

[0036] Typically, during initiation and / or termination of a dose dispensing procedure, the longitudinal distance between consecutive arranged stop faces of the first profile structure is related to or substantially equal to a step length determined by the longitudinal distance between the first longitudinal position and the second longitudinal position of the first elongated member.

[0037] According to a further example, the first profile section comprises a first counter stop face facing in the proximal direction and configured to engage with the stop face(s) of the first profile structure. In this way, any distally directed displacement of the first elongated component relative to the second elongated component can be unalterably transmitted to the dose limiter. Prior to a first dose dispensing procedure, the first counter stop face of the first profile section will axially abut the distally facing first stop face of the first profile structure. After termination of the first dispensing procedure, the first counter stop face of the first profile section will longitudinally or axially abut, engage or align with a second or consecutive stop face of the first profile structure of the first elongated component, etc.

[0038] In this way and with each stepwise movement of the first elongated component relative to the second elongated component distally, the first counter stop face of the first profile section of the dose limiter engages with a consecutive stop face of the plurality of stop faces of the first profile structure.

[0039] According to another example, the second profile structure of the second elongated component comprises a plurality of retaining faces. The retaining faces are consecutively arranged in the longitudinal direction and face in the distal direction. Typically, the retaining faces of the second profile structure are arranged in a regular, e.g. equidistant, manner along the longitudinal direction of the second elongated component. The longitudinal distance between consecutively or adjacently arranged distally facing retaining faces of the second profile structure typically coincides or correlates with the step length determined by the longitudinal distance between the first longitudinal position and the second longitudinal position of the first elongated component.

[0040] Typically, and prior to dispensing of a first dose of the medicament, the second profile structure abuts longitudinally or axially with a first retaining face. When the dose limiter is dragged or pushed in the distal direction by distally directed movement of the first elongated component relative to the second elongated component, the second profile section of the dose limiter will engage with a second retaining face of the second profile structure. The second retaining face is distally offset from the first retaining face by a well-defined axial or longitudinal distance determined by the step length. In this way and when the second profile section engages the distally facing second retaining face of the second profile structure, the dose limiter is effectively hindered from moving in the proximal direction relative to the second profile structure and thus relative to the second elongated component.

[0041] Thus, when the dose limiter has moved in distal direction relative to the second elongated component by a well-defined step length, its second profile section will engage with the retaining face of the second profile structure and thus will be hindered from moving in proximal direction relative to the second elongated component.

[0042] According to a further example, the second profile section of the dose limiter comprises a second counter stop face facing in the proximal direction and configured to engage with the retaining face of the second profile structure. When engaged with the distally facing retaining face of the second profile structure, the second counter stop face serves to hinder proximally directed movement of the second profile section and thus of the entire dose limiter relative to the second elongated component.

[0043] According to a further example, the mutual engagement between the first profile structure and the first profile section provides a unidirectional ratchet allowing and forcing distally directed movement of the first elongated component to be transmitted to the dose limiter. The mutual engagement further supports and allows proximally directed movement of the first elongated component relative to the dose limiter and thus relative to the second elongated component.

[0044] The mutual engagement of the second profile section of the dose limiter and the second profile structure of the second elongated component provides a unidirectional ratchet supporting distally directed movement of the dose limiter relative to the second elongated component but preventing and hindering proximally directed movement of the dose limiter relative to the second elongated component.

[0045] In other words, the mutual engagement of the first profile section and the first profile structure supports and allows proximally directed displacement of the first elongated component relative to the dose limiter but prevents distally directed displacement of the dose limiter relative to the first elongated component. Distally directed displacement of the first elongated component is unalterably transmitted to the dose limiter.

[0046] Generally, the first and second profile structures and the first and second profile sections of complementary shape can comprise pairs of mutually corresponding protrusions and recesses or recessed holes. For some examples, the first profile structure can comprise a plurality of teeth, e.g. teeth protruding radially or transversely from the first elongated component. Alternatively, the first profile structure comprises a hole provided with a plurality of stop faces, e.g. extending perpendicularly, transversely or in radial direction relative to the elongation of the first elongated component.

[0047] The first profile section of the dose limiter is shape-complementary. It can comprise a shape-complementary toothing with counter-stop surfaces protruding perpendicularly, transversely or in radial direction with respect to the elongation of the first elongated component. Likewise, the second profile structure can comprise a toothed structure with teeth protruding perpendicularly, transversely or in radial direction with respect to the elongation of the second elongated component.

[0048] Alternatively, the second profile structure comprises counter-stop surfaces extending substantially perpendicularly or in radial direction with respect to the elongation of the second elongated component. When the retaining surfaces of the second profile structure are provided as side walls of recesses of the second profile structure, the corresponding shaped second counter-stop surfaces of the second profile section protrude radially, transversely or perpendicularly with respect to the elongation of the second elongated component.

[0049] Conversely, when the second profile structure comprises a toothed structure with radially protruding teeth, wherein the retaining surfaces are provided on the radially protruding teeth, it is conceivable that the dose limiter and thus the shape-complementary second profile section comprises the second counter-stop surfaces in recessed portions or on protruding portions.

[0050] In either way and when the first profile structure comprises a plurality of recesses, the first profile section comprises protrusions. Conversely, when the first profile structure comprises a plurality of protruding teeth, the first profile section can comprise recesses to engage with the teeth or it can alternatively comprise protruding teeth to engage with the teeth of the first profile structure. The same applies to the mutual engagement between the second profile structure and the second profile section.

[0051] According to another example, the first elongated component and the second elongated component are rotatable relative to each other during dose setting. The first elongated component and the second elongated component are further rotationally locked during dose dispensing.

[0052] An engager mechanism can be provided which operates between the first elongated component and the second elongated component. The engager can be activated or deactivated by axial or longitudinal sliding of the first elongated component relative to the second elongated component. Typically, when the first elongated component is in the first longitudinal position or in the initial position, wherein the trigger of the injection device is not pressed, the first and second elongated components are free to rotate relative to each other. It is precisely upon distal movement of the first elongated component relative to the second elongated component, for example caused by pressing the trigger of the injection device, that the first elongated component is rotationally locked to the second elongated component.

[0053] For some examples, the first elongated member comprises a tubular sleeve and the second elongated member also comprises a tubular sleeve. The first and second elongated members can be arranged coaxially. They can be arranged in a nested fashion, with one of the first and second elongated members being radially inside the other of the first and second elongated members. For such implementations, the dose limiter is typically arranged radially between the first and second elongated members. For some examples, the dose limiter comprises a closed ring structure. For other examples, the dose limiter comprises an open ring structure or a semi-circular structure.

[0054] According to another example, the dose limiter is rotationally locked to one of the first elongated member and the second elongated member. The dose limiter is further rotatable to the other of the first elongated member and the second elongated member. Typically, the dose limiter can be rotationally locked to one of the first and second elongated members by means of a splined feature. Thus, one of the dose limiter and the respective elongated member comprises a radial protrusion slidably engaging a longitudinal extending recess or groove of the other of the dose limiter and the respective elongated member. In this way, a rotational interlock between the dose limiter and one of the first and second elongated members can be provided.

[0055] For some examples, the dose limiter is permanently rotationally locked to the second elongated member. It can be slidable in longitudinal direction along the second elongated member.

[0056] According to a further example, at least one of the first elongated member and the second elongated member comprises an end stop configured to engage with the dose limiter. The end stop can be provided at or near a distal end of the first elongated member and the second elongated member. When implemented in an injection device, the end stop can alternatively be provided on or by the housing of the injection device, or by some other component immovably fixed to the housing of the injection device.

[0057] Typically and when the end stop is provided on the first elongated member, it can serve to prevent or prohibit proximally directed movement of the first elongated member relative to the dose limiter and thus relative to the second elongated member, provided that the dose limiter is in proximal axial engagement with the second elongated member. By this configuration, a trigger or trigger button, which is longitudinally connected to the first elongated member and has been pressed in distal direction after a dose dispensing procedure, for example, can be blocked from returning to an initial position. This would then be a clear indication to the user that the allowable or intended total number of dose injection procedures has been performed.

[0058] For another example, when the end stop is provided on or by the second elongated member, it can be operable to block further distal directed movement of the dose limiter beyond the end stop caused by the first elongated member. Thus, when the dose limiter has reached the end stop on or at the second elongated member, its further movement in distal direction relative to the second elongated member is blocked. In this way and due to the dose limiter being blocked from moving in distal direction relative to the second elongated member, the distal directed movement of the first elongated member relative to the second elongated member is effectively blocked.

[0059] In this way, the distal movement of the first elongated member relative to the second elongated member is hindered. When implemented in the injection device, the trigger of the injection device is locked against a distal directed pressing caused by the user.

[0060] Thus, for further embodiments, the end stop of the first elongated member is configured to prevent proximal directed longitudinal movement of the first elongated member relative to the dose limiter or relative to the second elongated member when engaged with the dose limiter. Here, the end stop can comprise a proximally facing abutment face for engaging with a distally facing abutment face of the dose limiter. The mutual abutment or engagement of the mutually corresponding abutment faces of the first elongated member and the dose limiter prevents and blocks the proximal directed movement of the first elongated member relative to the dose limiter.

[0061] According to further examples, the end stop of the second elongated member is configured to prevent or block the distal directed longitudinal movement of the first elongated member relative to the dose limiter or relative to the second elongated member when engaged with the dose limiter.

[0062] Here, the dose limiter can comprise a distally facing abutment face configured to be in longitudinal abutment or longitudinal engagement with a proximally facing abutment face of the end stop of the second elongated member. In this way, the mutual abutment of the respective shaped abutment faces prevents and blocks the distal directed displacement of the dose limiter beyond the end stop of the second elongated member.

[0063] Thus, when the first elongated member, in particular its first profile structure, is in longitudinal abutment or engagement with the first profile section of the dose limiter, the first elongated member cannot be moved further in distal direction relative to the dose limiter, thus relative to the second elongated member. Any further or repeated dose dispensing action is thus blocked.

[0064] According to a further example, the end stop and the dose limiter are configured to be rotationally interlocked when the dose limiter overlaps the end stop in the longitudinal direction. In this way and when the stop configuration is reached, the dose limiter is blocked from rotating relative to the end stop. This is particularly beneficial when the dose limiter is permanently rotationally engaged or rotationally locked to, for example, the second elongated member but is free to rotate relative to the first elongated member. Here, the end stop will be provided at a predetermined longitudinal position of the first elongated member. When the dose limiter reaches the respective end stop configuration, it is rotationally locked to the first elongated member.

[0065] Since the dose limiter is rotationally interlocked or rotationally constrained to the second elongated member, the second elongated member will also be rotationally interlocked to the first elongated member. For some examples, where the first elongated member is blocked from rotating during the dose setting procedure, while the second elongated member has to be rotated to set the dose, once the dose limiter is rotationally engaged with the end stop, further dose setting actions can be blocked and hindered.

[0066] For another example, the dose limiter is permanently rotationally locked to the first elongated member and is free to rotate relative to the second elongated member. Here, the end stop configured to rotationally engage with the dose limiter is provided on the second elongated member. In this way, when the dose limiter is rotationally interlocked with the end stop, a similar rotational interlock between the first elongated member and the second elongated member will be obtained.

[0067] According to another example, one of the end stop and the dose limiter comprises at least one locking tooth, and the other of the end stop and the dose limiter comprises a gear ring to rotationally engage with the at least one locking tooth.

[0068] The member provided with the at least one locking tooth can also comprise at least a second locking tooth, which is located at a circumferential offset from the first locking tooth, which is also configured to rotationally engage with the gear ring. In this way, at least a double rotational interlock between the end stop and the dose limiter can be obtained. This provides for a rather robust and fail-safe mutual interlock configuration between the dose limiter and the end stop.

[0069] When the dose limiter and the end stop are configured to be rotationally interlocked, the first and second elongated members are typically provided as tubular sleeves, respectively. For some examples, the at least one locking tooth or plurality of locking teeth are provided on the outer circumference of the first elongated member, thereby providing or constituting the end stop. Here, the gear ring is provided on the inner side surface of the annular or semi-annular dose limiter.

[0070] For other examples, the gear ring can be provided on the outer side surface of the first elongated member, while the at least one or several locking teeth are provided on the inner side surface of the dose limiter.

[0071] For another example, the first elongated member comprises a drive sleeve, which is movable relative to the housing of the injection device in the distal direction from a first longitudinal position to a second longitudinal position, wherein, when in the first longitudinal position, the drive sleeve is rotationally constrained to the housing, and wherein, when in the second longitudinal position, the drive sleeve is free to rotate relative to the housing.

[0072] The dose limiting mechanism or the drive mechanism of the injection device can further comprise a lead screw configured to be operably engaged with a piston of the cartridge in order to displace the piston relative to a barrel of the cartridge, thereby expelling a dose of the medicament from the cartridge.

[0073] The drive sleeve can be operably engaged with the lead screw such that rotation of the drive sleeve relative to the housing of the injection device causes or results in a distally directed movement of the lead screw relative to the housing and / or relative to the barrel of the cartridge.

[0074] According to another example, the second elongated member comprises a number sleeve or dose dial, which is longitudinally constrained to the housing and free to rotate relative to the housing. The number sleeve typically comprises a continuous sequence of numbers indicating the size of the currently set or dispensed dose. Typically, only a portion of the number sleeve is visible from the outside of the housing of the injection device. In order to set a dose, the number sleeve is rotated relative to the housing in a first direction. During or in order to dispense a dose, the number sleeve is rotated in an opposite direction, thus in a second direction. During setting of a dose, the first elongated member, e.g. in the form of a drive sleeve, is rotationally locked to the housing, while the second elongated member, e.g. in the form of a number sleeve, is rotated relative to the housing and relative to the first elongated member.

[0075] At the start of the dose dispensing action and with the trigger of the injection device being pressed by the user, the first elongated member performs a longitudinally and distally directed movement relative to the housing and / or relative to the second elongated member, thereby further pushing or dragging the dose limiter one step in distal direction until a second longitudinal position is reached, in which the dose limiter is engaged with the second elongated member and in which the dose limiter is blocked from moving in proximal direction relative to the second elongated member.

[0076] During or for dispensing a dose, an interface between the first elongated member and the second elongated member can be closed, such that the first and second elongated members, i.e. the number sleeve and the drive sleeve, rotate in unison.

[0077] The distally directed movement of the first elongated member and thus of the drive sleeve can also open an interface by which the first elongated member is rotationally constrained or rotationally locked to the housing.

[0078] According to another example, the longitudinal movement of the first elongated member relative to the second elongated member or the longitudinal movement of the first elongated member relative to the housing of the injection device is controlled by a dispensing spring. Thus, the first elongated member can be longitudinally engaged with the dispensing spring which serves as a return spring. The first elongated member can be moved from the first longitudinal position and into the second longitudinal position by the bias of the dispensing or return spring.

[0079] Upon release in the second longitudinal position, the dispensing or return spring is operable to move the first elongated member back to the first longitudinal position.

[0080] In one aspect, the present disclosure relates to an injection device for setting and dispensing a dose of a medicament. The injection device comprises a housing for accommodating a cartridge filled with a liquid medicament. The injection device further comprises a lead screw for operable engagement with the cartridge for expelling a dose of the medicament from the cartridge. The injection device further comprises a dose dial for setting or dialling a variable size dose. Typically, the dose dial is rotationally supported on the housing of the injection device. It can be provided at or near the proximal end of the housing.

[0081] The injection device further comprises a trigger for initiating the dose dispensing. The trigger can also be implemented and used to control the dose dispensing. Further, the injection device comprises a dose limiter mechanism as described above. Here, the first elongated member of the dose limiter mechanism is longitudinally engaged or longitudinally connected with the trigger of the injection device. The second elongated member of the dose limiter mechanism is longitudinally constrained to the housing. In this way and when the trigger of the injection device is pressed in a distal direction, the first elongated member is moved in a corresponding stepwise movement in a distal direction relative to the second elongated member. In this way, the dose limiter is moved in a distal direction in well-defined steps until it engages the second elongated member, by which means the dose limiter is blocked from moving proximally when the trigger is released, e.g. at the end of the dose dispensing procedure. In this way, the first elongated member is allowed to return towards the first longitudinal position in a proximal direction.

[0082] According to a further example, the injection device comprises a cartridge as described above filled with the liquid medicament and arranged inside the housing. The cartridge can be easily assembled inside the injection device. The injection device can be implemented as a pen-type injector. When the cartridge with the medicament is assembled inside the housing of the injection device, it can be implemented as a disposable device.

[0083] For other examples, the injection device is implemented as a reusable device. Here, the housing of the injection device can be opened or can be detached in order to enable replacement of the cartridge.

[0084] The injection device can be implemented as an automatic spring driven injection device. Here, the injection device can comprise a drive spring, e.g. implemented as a torsion spring. The drive spring can be configured to store mechanical energy. The drive spring can be biased during dose setting, e.g. when the dose dial of the injection device is rotated in a first direction, e.g. in a dose incrementing direction. The drive spring, which is normally pre-biased, will be further biased by the dose dial action. Upon pressing the trigger, the mechanical energy stored in the drive spring and e.g. collected during dose setting will be released. The energy released from the drive spring can be sufficient to rotate the drive sleeve and move or dispense the medicament dose in a distal direction.

[0085] Generally, the scope of the present disclosure is defined by the content of the claims. The injection device is not limited to the specific embodiments or examples, but includes any combination of elements of different embodiments or examples. Within this scope, the present disclosure covers any technically feasible combination of claims and any technically feasible combination of features disclosed in connection with different examples or embodiments.

[0086] In the present context, the term "distal" or "distally" relates to the end of the injection device that faces the injection site of a human or animal. The term "proximal" or "proximally" refers to the opposite end of the injection device, which is furthest away from the injection site of a human or animal.

[0087] The terms "drug" or "medicament" are used synonymously herein and describe a pharmaceutical formulation containing one or more active pharmaceutical ingredients or pharmaceutically acceptable salts or solvates thereof, and optionally a pharmaceutically acceptable carrier. In the broadest sense, an active pharmaceutical ingredient ("API") is a chemical structure that has a biological effect on humans or animals. In pharmacology, a drug or medicament is used in the treatment, cure, prevention, or diagnosis of disease or used to otherwise enhance physical or mental well-being. A drug or medicament can be used for a limited period, or on a regular basis, for chronic disorders.

[0088] As described below, a drug or medicament can include at least one API, or combinations thereof, in various types of formulations, for the treatment of one or more diseases. Examples of API can include small molecules having a molecular weight of 500 Da or less; polypeptides, peptides and proteins (e.g., hormones, growth factors, antibodies, antibody fragments, and enzymes); carbohydrates and polysaccharides; and nucleic acids, double or single stranded DNA (including naked DNA and cDNA), RNA, antisense nucleic acids such as antisense DNA and RNA, small interfering RNA (siRNA), ribozymes, genes, and oligonucleotides. Nucleic acids can be incorporated into molecular delivery systems such as vectors, plasmids, or liposomes. Mixtures of one or more drugs can also be contemplated.

[0089] A drug or medicament contained in a drug delivery device as described herein can be used for the treatment and / or prophylaxis of many different types of medical disorders. Examples of disorders include, e.g., diabetes mellitus or complications associated with diabetes mellitus such as diabetic retinopathy, thromboembolic disorders such as deep vein or pulmonary thromboembolism. Further examples of disorders are acute coronary syndrome, angina, myocardial infarction, cancer, macular degeneration, inflammation, hay fever, atherosclerosis, and / or rheumatoid arthritis. Examples of APIs and drugs are those listed in publications such as the Rote Liste 2014, main groups 12 (antidiabetika) or 86 (onkologische

[0090] A drug or medicament contained in a drug delivery device as described herein can be used for the treatment and / or prophylaxis of many different types of medical disorders. Examples of disorders include, e.g., diabetes mellitus or complications associated with diabetes mellitus such as diabetic retinopathy, thromboembolic disorders such as deep vein or pulmonary thromboembolism. Further examples of disorders are acute coronary syndrome, angina, myocardial infarction, cancer, macular degeneration, inflammation, hay fever, atherosclerosis, and / or rheumatoid arthritis. Examples of APIs and drugs are those listed in publications such as the Rote Liste 2014, main groups 12 (antidiabetika) or 86 (onkologische

[0091] Examples of APIs used in the treatment and / or prophylaxis of diabetes mellitus type 1 or type 2 or complications associated with diabetes mellitus type 1 or type 2 include an insulin (e.g., human insulin, or a human insulin analogue or derivative, glucagon-like peptide-1, a GLP-1 analogue or a GLP-1 receptor agonist, or an analogue or derivative thereof, a dipeptidyl peptidase-4 (DPP4) inhibitor, or a pharmaceutically acceptable salt or solvate thereof, or any mixture thereof. As used herein, the terms “analogue” and “derivative” refer to a polypeptide which has a molecular structure which can formally be derived from the structure of a naturally occurring peptide (e.g., the structure of human insulin) by deleting and / or exchanging at least one amino acid residue occurring in the naturally occurring peptide and / or by adding at least one amino acid residue. The added and / or exchanged amino acid residue can be a codable amino acid residue or other naturally occurring residue or a purely synthetic amino acid residue. Insulin analogues are also referred to as “insulin receptor ligands”. In particular, the term “derivative” refers to a polypeptide which has a molecular structure which can formally be derived from the structure of a naturally occurring peptide (e.g., the structure of human insulin) in which one or more organic substituent (e.g., a fatty acid) is bound to one or more amino acids. Optionally, one or more amino acids occurring in the naturally occurring peptide can have been deleted and / or replaced by other amino acids, including non-codable amino acids, or amino acids, including non-codable amino acids, have been added to the naturally occurring peptide.

[0092] Examples of insulin analogues are Gly(A21 ), Arg(B31 ), Arg(B32) human insulin (insulin glargine); Lys(B3), Glu(B29) human insulin (insulin glulisine); Lys(B28), Pro(B29) human insulin (insulin lispro); Asp(B28) human insulin (insulin aspart); human insulin, wherein proline in position B28 is replaced by Asp, Lys, Leu, Val or Ala and wherein in position B29 Lys can be replaced by Pro; Ala(B26) human insulin; Des(B28-B30) human insulin; Des(B27) human insulin and Des(B30) human insulin.

[0093] Examples of insulin derivatives are, for example, B29-N-myristoyl-des(B30) human insulin, Lys(B29) (N- tetradecanoyl)-des(B30) human insulin (insulin detemir, ); B29-N-palmitoyl-des(B30) human insulin; B29-N-myristoyl human insulin; B29-N- palmitoyl human insulin; B28-N-myristoyl LysB28ProB29 human insulin; B28-N- palmitoyl-LysB28ProB29 human insulin; B30-N-myristoyl-ThrB29LysB30 human insulin; B30-N-palmitoyl-ThrB29LysB30 human insulin; B29-N-(N-palmitoyl-Y-glutamyl)- des(B30) human insulin, B29-N-o-carboxypentadecanoyl-gamma-L-glutamyl-des(B30) human insulin (Dean insulin,. ); B29-N-(N-lithocholyl-Y-glutamyl)-des(B30) human insulin; B29-N-(ooxocarheptyloyl)- des(B30) human insulin and B29-N-(ooxocarheptyloyl) human insulin.

[0094] Examples of GLP-1, GLP-1 analogues and GLP-1 receptor agonists are, for example, Lixlentide Exendin-4, a 39 amino acid peptide produced by the salivary glands of the Gila monster), Liraglutide Semaglutide, Taspoglutide, Albiglutide Dulaglutide rExendin-4, CJC-1134-PC, PB-1023, TTP-054, Langlenatide / HM-11260C (Efpeglenatide), HM-15211, CM-3, GLP-1 Eligen, ORMD-0901, NN-9423, NN-9709, NN-9924, NN-9926, NN-9927, Nodexen, Viador-GLP-1, CVX-096, ZYOG-1, ZYD-1, GSK-2374697, DA-3091, MAR-701, MAR 709, ZP-2929, ZP-3022, ZP-DI-70, TT-401 (Pegapamodtide), BHM-034, MOD-6030, CAM-2036, DA-15864, ARI-2651, ARI-2255, Tirzepatide (LY3298176), Bamadutide (SAR425899), Exenatide-XTEN and Glucagon-XTEN.

[0095] Examples of oligonucleotides are e.g. mipomersen sodium It is a cholesterollowering antisense therapeutic for the treatment of familial hypercholesterolemia or RG012 for the treatment of Alport syndrome.

[0096] Examples of DPP4 inhibitors are Linagliptin, Vildagliptin, Sitagliptin, Denagliptin, Saxagliptin, Berberine.

[0097] Examples of hormones include pituitary or hypothalamic hormones or regulatory active peptides and antagonists thereof, such as gonadotropins (follicle-stimulating hormone, luteinizing hormone, chorionic gonadotropin, menotropin), somatropin, desmopressin, terlipressin, goserelin, triptorelin, leuprolide, buserelin, nafarelin and goserelin.

[0098] Examples of polysaccharides include glucosaminoglycane, hyaluronic acid, heparin, low molecular weight heparin or ultra low molecular weight heparin or derivatives thereof, or sulfated polysaccharides (e.g. polysulfated forms of the above polysaccharides), and / or pharmaceutically acceptable salts thereof. An example of a pharmaceutically acceptable salt of polysulfated low molecular weight heparin is enoxaparin sodium. An example of a hyaluronic acid derivative is Hylan G-F 20 It is a sodium hyaluronate.

[0099] The term "antibody", as used herein, refers to an immunoglobulin molecule or an antigen binding portion thereof. Examples of antigen binding portions of immunoglobulin molecules include F(ab) and F(ab')2 fragments, which retain the ability to bind antigen. The antibody can be a polyclonal antibody, a monoclonal antibody, a recombinant antibody, a chimeric antibody, a de-immunized antibody or a humanized antibody, a fully human antibody, a non-human antibody (e.g., a murine antibody), or a single chain antibody. In some embodiments, the antibody has effector function and can fix complement. In some embodiments, the antibody has reduced or no ability to bind the Fc receptor. For example, the antibody can be of an isotype or subtype that does not support Fc receptor binding (e.g., IgG2 or IgG6), or it can be an antibody fragment or mutant, such as one that lacks part of the Fc receptor binding region. The term "antibody" also includes antigen binding molecules based on tetravalent bispecific tandem immunoglobulins (TBTI) and / or dual variable region antibody-like binding proteins with cross-over binding region orientation (CODV).

[0100] The term "fragment" or "antibody fragment" refers to polypeptides derived from an antibody polypeptide molecule (e.g., an antibody heavy and / or light chain polypeptide) that do not comprise a full-length antibody polypeptide, but that still comprise at least a portion of a full-length antibody polypeptide that is capable of binding to an antigen. Antibody fragments can comprise a cleaved portion of a full-length antibody polypeptide, although the term as used herein is not limited to such cleaved fragments. Antibody fragments that are useful in the present application include, for example, Fab fragments, F(ab')2 fragments, scFv (single-chain Fv) fragments, linear antibodies, monospecific or multispecific antibody fragments such as bispecific, trispecific, tetraspecific and multispecific antibodies (e.g., diabodies, triabodies, tetrabodies), monovalent or multivalent antibody fragments such as bivalent, trivalent, tetravalent and multivalent antibodies, minibodies, chelating recombinant antibodies, tribodies or bibodies, intrabodies, nanobodies, small modular immunopharmaceuticals (SMIPs), binding-domain immunoglobulin fusion proteins, camelized antibodies, and VHH containing antibodies. Additional examples of antigen-binding antibody fragments are known in the art.

[0101] The term "complementarity determining region" or "CDR" refers to short polypeptide sequences within the variable region of both heavy and light chain polypeptides that are primarily responsible for mediating specific antigen recognition. The term "framework region" refers to amino acid sequences within the variable region of both heavy and light chain polypeptides that are not CDR sequences, and that primarily serve to maintain correct positioning of the CDR sequences to permit antigen binding. Although the framework regions themselves typically do not directly participate in antigen binding, as is known in the art, certain residues within the framework regions of certain antibodies can directly participate in antigen binding, or can affect the ability of one or more amino acids in CDRs to interact with an antigen.

[0102] Examples of antibodies are anti-PCSK-9 mAbs (e.g., Alirocumab), anti-IL-6 mAbs (e.g., Sarilumab), and anti-IL-4 mAbs (e.g., Dupilumab).

[0103] Pharmaceutically acceptable salts of any API described herein are also contemplated for use in the drug or medicament in drug delivery devices. Pharmaceutically acceptable salts are for example acid addition salts and basic salts.

[0104] Those of skill in the art will appreciate that modifications (additions and / or removals) of various components of the APIs, formulations, devices, methods, systems and embodiments described herein can be made without departing from the full scope and spirit of the present application, which encompass such modifications and any and all equivalents thereof.

[0105] It will be further apparent to those of ordinary skill in the art that various modifications and changes can be made to the disclosed implementations without departing from the scope of the disclosure. Further, it should be noted that any reference signs in the appended claims should not be construed as limiting the scope of the disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0106] In the following, a number of examples of dose limiting mechanisms and injection devices will be described in more detail with reference to the drawings, in which:

[0107] Fig. 1 shows an exploded view of an example of an injection device,

[0108] Fig. 2 shows an exploded view of a further example of an injection device,

[0109] Fig. 3 is a perspective view of a sliding element of the device in Fig. 2,

[0110] Fig. 4 is a perspective view of a number sleeve of the device in Fig. 2,

[0111] Fig. 5 is a perspective view of a further section of the number sleeve in Fig. 4,

[0112] Fig. 6 is a perspective view of a drive spring of the device in Fig. 2,

[0113] Figs. 7a and 7b are perspective views of a button and a number sleeve of the device in Fig. 2,

[0114] Fig. 8 is a perspective view of parts of a drive spring of the device in Fig. 2,

[0115] Figs. 9a and 9b are perspective views of a drive sleeve and an engager plate of the device in Fig. 2,

[0116] Figs. 10a and 10b show a dose setting sequence of the device in Fig. 2 in side view,

[0117] Fig. 11 is a perspective view of a button and a housing of the device in Fig. 2,

[0118] Fig. 12 is a cross-sectional view of the device in Fig. 2,

[0119] Figs. 13a and 13b show the interaction between a drive sleeve and a number sleeve of the device in Fig. 2.

[0120] Fig. 14 shows a schematic view of an example of a dose limiting mechanism for use with or integrated with an injection device, with a first elongated member in a first longitudinal position,

[0121] Fig. 15 shows the dose limiting mechanism according to Fig. 14, with the first elongated member in a second longitudinal position,

[0122] Figure 16 shows the dose limiting mechanism of Figures 14 and 15 after the first elongated member has been returned from the second longitudinal position to the first longitudinal position,

[0123] Figure 17 illustrates an example of a dose limiting mechanism in which an end stop is provided on the second elongated member,

[0124] Figure 18 illustrates another example of a dose limiting mechanism in which an end stop is provided on the first elongated member,

[0125] Figure 19 illustrates another example of a dose limiting mechanism in which the first elongated member is provided by a drive sleeve of the injection device,

[0126] Figure 20 shows a schematic view of the second elongated member of the dose limiting mechanism implemented as a number sleeve of the injection device,

[0127] Figure 21 is a perspective view of an example of a dose limiter cooperating with the first and second elongated members illustrated in Figures 19 and 20.

[0128] Figure 22 shows a portion of a longitudinal section through a portion of the dose limiter of Figure 21, and

[0129] Figure 23 shows a portion of a cross section through the dose limiter of Figure 21. DETAILED DESCRIPTION

[0130] Figure 1 shows an exploded view of a first embodiment of an injection device 1, the components of which are a dose dial in the form of a dialling button 2, a housing or body 3, a dose scale drum or number sleeve 4 having an external thread 5 extending helically on its outer peripheral surface from a distal end to a proximal end. The scale drum 4 carries indicia 6 printed on the scale drum. The indicia 6 are helically disposed on the scale drum 4.

[0131] The housing or body 3 has an elongate window or aperture 7 of rectangular shape having two longitudinal boundaries 8 extending parallel to a longitudinal axis 9 of the injection device and two radial boundaries 10 perpendicular to the longitudinal axis 9. Through the window 7, a user can inspect the scale drum 4.

[0132] The dose dial 2 is axially retained in the housing 3 and the scale drum 4 is directly coupled to the dialling button 2 to follow the rotation of the dialling button 2 so that when a user rotates the dialling button 2 to select a dose, the scale drum 4 rotates with the dialling button 2. The dialling button 2 and the scale drum 4 are arranged so that they both rotate without any axial displacement. The dose dial 2 also has the function of a dose or trigger button. The connection between the dialling button 2 and the scale drum 4 can be achieved by a releasable coupling so that the dialling button 2 does not necessarily rotate back with the scale drum 4 when the injection is set.

[0133] The outer helical thread 5 of the scale drum 4 engages a corresponding male thread of the sliding element 11. The sliding element 11 has a tubular section and a window or sliding window 12, wherein on both axial sides of the window 12 a male thread is formed which engages the helical thread 5 of the scale drum 4. In a further embodiment of the shown device the inner surface of the sliding element 11 is in sliding contact with the outer surface of the scale drum between adjacent thread turns of the scale drum.

[0134] The inner surface of the housing 3 is provided with longitudinal strips which guide the sliding element 11 in axial direction but prevent relative rotation between the sliding element 11 and the housing 3. The longitudinal strips engage longitudinal recesses 13 on the outer surface of the sliding element 11. Due to this engagement and the engagement between the threads of the housing 3 and the sliding element 11 the sliding element 11 is axially moved each time the scale drum 4 is rotated. The axial movement of the sliding element 11 and thus of the sliding window 12 relative to the longitudinal window 7 in the housing 3 is coordinated with the helical pattern of the markings 6 printed on the scale drum 4 such that at the same time only one marking 6 is present in the longitudinal window 7 and the sliding window 12.

[0135] The drive spring 14 is connected at one end to the scale drum 4 and at the other end to the housing 3 such that relative rotation between the scale drum 4 and the housing 3 energizes the drive spring.

[0136] The axial length of the sliding element 11 is sufficient to cover the visible part of the helical track 5 of the scale drum 4 in order to completely prevent the user from viewing the invisible markings 6 through the sliding window 12. For this purpose the sliding element 11 has an extension 15 which extends in axial direction, wherein the distal end 16 and the proximal end 17 of the sliding element 11 are formed not to collide with the border 10 of the window 7. For this purpose the distal border 10 can have a receiving section for receiving the extension such that the window 12 of the sliding element 11 can be placed over each single number on the scale drum 4.

[0137] Fig. 2 shows an exploded view of the components of a further embodiment of the injection device.

[0138] The device 1 comprises a dose dial 2 in the form of a dial grip, a housing and / or housing body 3 with an elongated window 7, a dose scale drum in the form of a number sleeve 4 having an external thread 5 extending helically on its outer peripheral surface from the distal end towards the proximal end. The number sleeve 4 carries markings 6 printed on the scale drum. The markings 6 are helically located on the scale drum 4. The device further comprises a trigger button 18, a sliding element 11 configured as a metering member with a sliding window 12, an engager plate 19, a last dose nut 20, a drive sleeve 21, an engager spring 22, a lead screw 23, a bearing 24 provided at the distal end of the lead screw 23, a drive spring 14 in the form of a torsion spring, a cartridge holder 25 which can be attached to the distal end of the housing 3 and receives a cartridge 26 filled with a medicament and having a stopper or piston (not shown) inside, wherein when the bearing 24 is moved in the distal direction, the bearing displaces the stopper so that when a dispensing interface such as a double ended needle cannula is attached to the distal end of the cartridge, the medicament is dispensed from the cartridge 26. The number sleeve 4 comprises an upper number sleeve portion 27 referred to as number sleeve upper portion and a lower number sleeve portion 28 referred to as number sleeve lower portion. In contrast to the embodiment in figure 1, the dose dial 2 and the button 18 are separate independent components. All components are positioned concentrically around a common main longitudinal axis of the mechanism. The body 3 can also be a body element fixed to an outer housing or outer shell.

[0139] The button 18 is permanently splined to the dose dial 2. When the button 18 is not pressed, it is also splined to the number sleeve upper portion 28, but this splined interface is disconnected when the button 18 is pressed. When the button 18 is pressed, the splines on the button 18 engage with splines on the housing 3, thereby preventing the button 18 (and thus the dose dial 2) from rotating during dispensing. When the button 18 is released, the splines disengage, thereby allowing dialling of a dose. The dose dial 2 is axially constrained to the housing 3. It is rotationally constrained to the button 18 via the splined interface. The number sleeve lower portion 28 is rigidly fixed to the number sleeve upper portion 27 during assembly to form the number sleeve 4 and is a separate component to simplify number sleeve 4 moulding and assembly. This sub-assembly is constrained to the housing 3 by holding elements (not shown) towards the distal end to allow rotation but not translation. The number sleeve lower portion 28 is marked with a series of markings in the form of numbers which are visible through the window 12 of the sliding element 11 and the window 7 in the housing 3 to indicate dialled doses of medicament.

[0140] The adapter plate 19 is splined to the number sleeve 4. It is also coupled to the drive sleeve 21 via a ratchet interface. The ratchet provides detent positions corresponding to each unit of dose between the number sleeve 4 and the drive sleeve 21 and engages different angled splines during clockwise and counter clockwise relative rotation. The slider element 11 is constrained against rotation but is allowed to translate relative to the housing 3 via the splined interface. The slider element 11 has a helical feature on its inner surface which engages with a helical thread 5 cut in the number sleeve 4 such that rotation of the number sleeve 4 causes axial translation of the slider element 11. This helical feature on the slider element 11 also forms a stop abutment against the end of the helical cut in the number sleeve 4 to limit the minimum and maximum dose that can be set.

[0141] In Figures 1 to 13b, the last dose nut 20 is located between the number sleeve 4 and the drive sleeve 21. It is rotationally constrained to the number sleeve 4 via a splined interface. The last dose nut moves along a helical path relative to the drive sleeve 21 via a threaded interface when relative rotation between the number sleeve 4 and the drive sleeve 21 occurs. The drive sleeve 21 extends from an interface with the adapter plate 19 to contact with the adapter spring 22. The splined tooth interface with the number sleeve 4 is not engaged during dialling but is engaged when the button 18 is pressed, preventing relative rotation between the drive sleeve 21 and the number sleeve 4 during dispensing. The splined tooth interface with the housing 3 prevents rotation of the drive sleeve 21 during dose setting. When the button 18 is pressed, the drive sleeve 21 is disengaged from the housing 3, allowing the drive sleeve 21 to rotate.

[0142] The helical drive spring 14 is energised and stores energy by the action of the user rotating the dose dial 2 during dose setting. The spring energy is stored until the mechanism is triggered for dispensing, at which point the stored energy is used to deliver medicament from the cartridge to the user. The drive spring 14 is attached at one end to the housing 3 and at the other end to the number sleeve 4. The drive spring 14 is pre-wound at assembly such that when the mechanism is at zero unit dialling, the drive spring applies a torque to the number sleeve 4. The rotational action of the dose dial 2 to set a dose rotates the number sleeve 4 relative to the housing 3 and further energises the drive spring 14.

[0143] The lead screw 23 is rotationally constrained to the drive sleeve 21 via a splined interface. When rotated, the lead screw 23 is forced to move axially relative to the drive sleeve 21 by a threaded interface with the housing 3 (not shown). A bearing 24 is axially constrained to the lead screw 23 and acts on a bung within the liquid medicament cartridge 26.

[0144] The axial position of the drive sleeve 21, the engager plate 19 and the button 18 is defined by the action of the engager spring 22 which exerts a force on the drive sleeve 21 in the proximal direction. This spring force is reacted via the drive sleeve 21, the engager plate 19 and the button 18 and when “at rest” the spring force is further reacted by the dose dial 2 to the housing 3. The spring force ensures that the ratchet interface is always engaged. In the “at rest” position it also ensures that the button spline is engaged with the number sleeve 4 and the drive sleeve teeth are engaged with the housing 3. The housing 3 provides the location for the liquid drug cartridge and the cartridge holder 25, a window for viewing the dose numbers and the sliding element and features on its outer surface for axially retaining the dose dial 2 (not shown). The removable cap fits over the cartridge holder 25 and is retained via a clip feature on the housing 3.

[0145] Figure 3 shows the interior of the sliding element 11 which has a window 12 and a male threaded feature 29 on its inner surface which engages the outer thread 5 on the number sleeve 4 (see figure 4). The threaded feature 29 has a zero dose abutment 30 and a maximum dose abutment 31. As shown in figure 4, the outer thread 5 has a zero dose abutment 32 at one end of the thread 5 and a maximum dose abutment 33 at the other end of the thread 5 so that any dose size between zero and a predefined maximum can be selected to suit the medicament and user profile. The drive spring 14 (which has a number of pre-wound turns applied to it during assembly of the device) exerts a torque on the number sleeve 4 and is prevented from rotating by the zero dose abutment.

[0146] As shown in figure 5, the inner surface of the number sleeve 4 has a lead-in 34 followed by a recess 35 and an anchor point 36. The automatic assembly of the drive spring 14 into the number sleeve is achieved by incorporating the large lead-in 34 and recess feature 35. When the drive spring 14 is rotated during assembly, the hooked end structure 37 (see figure 6) at one end of the drive spring 14 sits in the recess feature 35 before it engages with the anchor point 36 in the number sleeve 4.

[0147] As shown in Figure 6, the drive spring 14 is formed from a helical wire having at least two different pitches. The two ends are formed from "closed" coils 38, i.e. the pitch is equal to the wire diameter and each coil touches the adjacent coil. The central portion has "open" coils 39, i.e. the coils do not touch each other. This has the following advantages. When setting the dose, the drive spring 14 is charged. If all the coils were closed, then winding the spring would increase the length of the spring by one wire diameter per turn, so the hook end would no longer be aligned with its anchor points on the housing and the number sleeve. The open coils allow the spring to compress to accommodate the extra turns without increasing the overall length of the spring. Furthermore, the open coils 39 allow the spring to be compressed during assembly. The spring is manufactured longer than the available space in the device. It is then compressed during assembly, thereby ensuring that the axial position of the hook end is better aligned with its anchor points on the housing and the number sleeve. Also, if most of the coils were closed, then it is easier to manufacture the spring to the specified length because the length of these coils is simply a function of the wire diameter. Furthermore, after assembly, the compression in the spring biases the number sleeve axially in a consistent direction relative to the housing, reducing the effect of geometric tolerances. Also, the addition of closed coils at each end makes the spring less prone to becoming entangled with each other when stored together between manufacture and assembly, and the closed coils at the ends provide flat surfaces for contact with the housing and the number sleeve.

[0148] To select a dose, the user rotates the dial grip 2 clockwise. As shown in Figures 7a and 7b, the button has internal splines 40 for engaging corresponding splines 41 on the upper part of the number sleeve 4 to form a splined interface 40 / 41. The dial grip splines are connected to the button 18, which has a further set of splines 42 for engaging corresponding splines of the housing 3. During dose selection, rotation of the dial grip is transmitted to the button 18. The button 18, in turn, is splined to the upper part of the number sleeve (only during dose selection). The upper part of the number sleeve is permanently fixed to the lower part of the number sleeve to form the number sleeve 4. Thus, rotation of the dial grip 2 causes the same rotation in the number sleeve 4. Rotation of the number sleeve 4 causes charging of the drive spring, thereby increasing the energy stored within it. As the number sleeve 4 rotates, the sliding element 11 translates axially due to its threaded engagement with the number sleeve 4, thereby showing the value of the dialled dose.

[0149] As shown in Figure 8, the drive sleeve 21 has splines 43 for engaging corresponding splines 44 formed on the inside of the housing 3 to form a splined interface 43 / 44. As a result of the engagement of the splined teeth 43 of the drive sleeve 21 with the teeth 44 of the housing 3, rotation of the drive sleeve is prevented when a dose is set and the number sleeve is rotated. Thus, relative rotation occurs between the driver plate, which is driven by the number sleeve, and the drive sleeve via the ratchet interface.

[0150] As shown in Figures 9a and 9b, the end face of the drive sleeve 21 is provided with a helical tooth 45 to form a ratchet interface 45 / 46 with the ratchet teeth 46 of the indexer plate 19. On the outer circumference of the indexer plate 19, splines 47 are formed for engagement with corresponding grooves on the number sleeve. The user torque required to turn the dial grip is the sum of the torque required to wind the drive spring and the torque required to index the ratchet feature 45 / 46. The indexer spring is designed to provide an axial force to the ratchet feature 45 / 46 and biases the indexer plate 19 onto the drive sleeve 21. This axial load acts to maintain the ratchet teeth of the indexer plate 19 in engagement with the drive sleeve 21. The torque required to index the ratchet in the dose setting direction is a function of the axial load applied by the indexer spring, the clockwise helix angle of the ratchet, the coefficient of friction between the mating surfaces and the average radius of the ratchet feature. When the user rotates the dial grip sufficiently to cause the mechanism to increment by one increment, the number sleeve 14 is rotated by one ratchet tooth relative to the drive sleeve 21. At this point, the ratchet teeth re-engage to the next detent position. The ratchet re-engagement produces an audible click and the change in required torque input gives tactile feedback.

[0151] Without the application of user torque to the dial grip 21, the number sleeve 4 is prevented from unwinding by the ratchet engagement 45 / 46 between the indexer plate 19 and the drive sleeve 21 only. The torque required to index the ratchet in the anticlockwise direction is a function of the axial load applied by the indexer spring 22, the anticlockwise helix angle of the ratchet 45 / 46, the coefficient of friction between the mating surfaces and the average radius of the ratchet feature. The torque required to index the ratchet must be greater than the torque applied to the number sleeve 4 (and hence the indexer plate 19) by the drive spring 14. Therefore, the ratchet helix angle is increased in the anticlockwise direction to ensure this, whilst ensuring the dial torque is as low as possible.

[0152] The user can choose to increase the selected dose by continuing to rotate the dial grip in the clockwise direction. For each dose increment, the process of indexing the ratchet interface between the number sleeve 4 and the drive sleeve 21 is repeated. For each dose increment, additional energy is stored in the drive spring 14 and audible and tactile feedback is provided for each increment of the dial by the re-engagement of the ratchet teeth. The torque required to rotate the dial grip 2 increases as the torque required to wind the drive spring 14 increases. Therefore, the torque required to index the ratchet in the anticlockwise direction must be greater than the torque applied to the number sleeve 4 by the drive spring 14 when the maximum dose has been reached.

[0153] If the user continues to increase the selected dose until the maximum dose limit is reached, the number sleeve 4 engages with its maximum dose abutment on the slide element (see Figures 3 and 4). This prevents further rotation of the number sleeve 4, the indexer plate 19 and the dial sleeve 2.

[0154] The last dose nut 20 is splined to the number sleeve 4, while the last dose nut 20 is threaded to the drive sleeve, such that relative rotation of the number sleeve to the drive sleeve during dose setting also causes the last dose nut to travel along its threaded path towards the last dose abutment on the drive sleeve. Depending on how many increments the mechanism has already delivered, the last dose nut can have its last dose abutment in contact with the drive sleeve during dose selection. The abutment prevents further relative rotation between the number sleeve 4 and the drive sleeve 21 and thus limits the dose that can be selected. The position of the last dose nut is determined by the total number of relative rotations between the number sleeve 4 and the drive sleeve 21 that have occurred each time the user sets a dose.

[0155] With a dose set, the user is able to deselect any number of increments from this dose. Deselection of the dose is achieved by the user rotating the dial grip 2 anticlockwise. The torque applied by the user to the dial grip 2, when combined with the torque applied by the drive spring 14, is sufficient to disengage the ratchet between the driver plate 19 and the drive sleeve 21 in the anticlockwise direction. When the ratchet 45 / 46 is disengaged, anticlockwise rotation occurs in the number sleeve 4 (via the driver plate 19) which returns the number sleeve 4 towards the zero dose position and releases the drive spring 14. Relative rotation between the number sleeve 4 and the drive sleeve 21 causes the last dose nut to return along its helical path away from the last dose abutment.

[0156] As shown in Figures 10a and 10b, the sliding element 11 has a flange or extension on either side of the window area which covers the number printed on the number sleeve adjacent to the dialled dose to ensure that only the dose number is visible to the user. In addition to the typical discontinuous dose number display on this type of device, the device also includes a visual feedback feature. The distal end of the sliding element 11 has an extension 15 (see Figure 2) which creates a sliding scale through a small window 48 in the housing 3. As the user sets a dose, the sliding element 11 translates axially, the distance moved being proportional to the dose magnitude set. This feature provides the user with explicit feedback about the approximate size of the dose set. Dispensing speed of an auto-injector mechanism can be higher than a manual injector device, so the digital dose display can not be readable during dispensing. The sliding element 11 provides feedback to the user about dispensing progress during dispensing without the need to read the dose number itself.

[0157] The window 48 can be formed by an opaque element on the sliding element 11 revealing the underlying contrasting coloured component 49 underneath. Alternatively, the revealable element 49 can be printed with a rough dose number or other index to provide a more accurate resolution. Furthermore, this display mimics the syringe action during dose setting and dispensing.

[0158] To reduce dust ingress and prevent user contact with moving parts, the viewing openings 7 and 48 in the housing 3 are covered by translucent windows. These windows can be separate components, but in this embodiment they are incorporated into the housing 3 using a 'two-shot' moulding technique. The 'first shot' of translucent material forms the internal features and windows, then the'second shot' of opaque material forms the outer cover of the housing 3.

[0159] Delivery of a dose is initiated by the user pressing the button axially. When the button 18 (see Figures 7a and 7b) is pressed, the splines 40 and 41 between the button 18 and the number sleeve 4 disengage, causing the button 18 and dial grip 21 to rotationally decouple from the delivery mechanism.

[0160] As shown in Figure 11, the splines 42 on the button 18 engage with splines 50 on the housing 3, preventing the button 18 (and hence the dial grip 21) from rotating during dispensing. Since the button 18 is stationary during dispensing, this can be used in the dispensing mechanism. A stop feature in the housing 3 limits the axial travel of the button 18, and reacts against any axial abuse loads applied by the user, reducing the risk of damage to internal components.

[0161] As shown in Figure 12, the adapter plate 19, which is disposed between the drive sleeve 21 and the button 18, moves axially with the button, and the drive sleeve 21 moves axially with the adapter plate 19.

[0162] As shown in Figures 13a and 13b, the axial displacement of the drive sleeve 21 causes the splines 51 on the drive sleeve 21 to engage with the splines 52 on the number sleeve 4, forming a spline tooth interface 51 / 52 which prevents relative rotation between the drive sleeve 21 and the number sleeve 4 during dispensing. The spline tooth interface 43 / 44 between the drive sleeve 21 and the housing 3 (Figure 8) disengages, so that the drive sleeve 21 can now rotate relative to the housing 3, and is driven by the drive spring via the number sleeve 4 and the adapter plate 19. Rotation of the drive sleeve 21 causes the lead screw 23 to rotate due to its spline engagement, and then the lead screw 23 advances due to its threaded engagement with the housing 3. Rotation of the number sleeve 4 also causes the slide element to move axially back to its zero position, whereby the zero dose abutment (Figures 3 and 4) stops the mechanism.

[0163] The spline teeth on the drive sleeve 21 or the housing 3 can be angled such that when the zero dose abutment 30 stops rotation of the number sleeve 4 at the end of a dose, and hence rotation of the drive sleeve 21, and the button 18 is released, the spline teeth between the drive sleeve 21 and the housing 3 cause the drive sleeve 21 to rotate a small amount backwards, and hence the lead screw 23 to move axially backwards away from the bung, and the number sleeve lower portion 28 to rotate from the zero dose stop position. This helps to prevent possible leakage.

[0164] In Figs. 14-18, the principle of a dose limiting mechanism 100 according to the present disclosure and configured for an injection device 1 is schematically illustrated, such as for example shown and described in connection with Figs. 1-13b. The dose limiting mechanism 100 is operable to limit the total number of doses that the injection device 1 can dispense. The dose limiting mechanism 100 comprises a first elongated member 110 extending in a longitudinal direction and comprising a first profiled structure 112. The dose limiting mechanism 100 further comprises a second elongated member 120 extending coaxially or in parallel with the first elongated member 110. The second elongated member 120 comprises a second profiled structure 122 facing the first profiled structure 112. A dose limiter 130 is further provided. The dose limiter 130 is arranged between the first elongated member 110 and the second elongated member 120. The dose limiter 130 comprises a first profiled section 131 and a second profiled section 132. The first profiled section 131 faces the first profiled structure 112. It is configured to engage, i.e. mechanically engage, with the first profiled structure 112 of the first elongated member 110. Likewise, the second profiled section 132 of the dose limiter 130 is configured to engage, i.e. mechanically engage, with the second profiled structure 122 of the second elongated member 120.

[0165] The mutual engagement of the first profiled structure 112 and the second profiled structure 122 with the respective first profiled section 131 and the second profiled section 132 causes a longitudinal movement, e.g. a longitudinal sliding movement, of the first elongated member 110 relative to the second elongated member 120 to be transferred to the dose limiter 130. Here, the dose limiter 130 is allowed to move in the distal direction 102 relative to the second elongated member 120. It can be pushed or dragged in the distal direction 102 by the first elongated member. It is hindered from moving proximally relative to the first elongated member 110. In this way, a distally directed movement of the first elongated member 110 is transferred to the dose limiter 130. This is immediately apparent from a comparison of Figs. 14 and 15.

[0166] The second profiled section 132 of the dose limiter 130 can further be engaged with the second profiled structure 122 to maintain the longitudinal position of the dose limiter 130 relative to the second member 120 when the first member should be moved longitudinally in the proximal direction 103 relative to the second elongated member 120. In other words, the mutual engagement of the second profiled section 132 with the second profiled structure 122 causes the dose limiter 130 to always be allowed to move distally relative to the second elongated member 120 but be hindered or blocked from moving in the proximal direction relative to the second elongated member 120.

[0167] Likewise, the first elongated component 110 is allowed to move in the proximal direction 103 relative to the dose limiter 130, but is blocked or hindered from moving in the distal direction 102 relative to the dose limiter 130. Any distally directed displacement of the first elongated component 110 relative to the second elongated component 120 is transmitted to the dose limiter 130. When the first elongated component 110 moves in the distal direction 102, the dose limiter 130 has to follow this distally directed movement. It is accordingly pushed in the distal direction 102.

[0168] For the presently illustrated example, the first profile structure 112 of the first elongated component 110 comprises a regular zigzag profile 113. The zigzag profile 113 comprises a plurality of teeth 118 arranged adjacent in the longitudinal direction. The teeth 118 comprise a rather steep flank which forms or constitutes a stop face 114 and faces in the distal direction 102. The teeth 118 further comprise a slightly inclined flank 119 facing the second elongated component 120.

[0169] The dose limiter 130 comprises a correspondingly shaped first profile section 131. The first profile section 131 comprises a counter stop face 133 facing in the proximal direction 103 and configured to engage with the distally facing stop face 114 of the teeth 118 of the profile structure 112 of the first elongated component 110.

[0170] The first profile section 132 of the dose limiter 130 is provided on a protrusion or projection 135 extending towards the first elongated component 110. The projection 135 is shaped to enter a transverse or radial recess formed by or adjacent to the stop faces 114, 114', 114" of the teeth 118.

[0171] The second profile section 132 of the dose limiter 130 facing the second elongated component 120 also comprises a transverse or radial projection 136 protruding towards the second elongated component 120. The projection 136 is shaped and configured to engage with the retaining faces 124, 124', 124" of the second profile structure 132. The retaining faces 124, 124', 124" are provided proximally of the respective recesses 126 which are arranged in a continuous and regular order in the longitudinal direction on the side of the second elongated component 120 facing the first elongated component 110.

[0172] As indicated in Figs. 14 to 16, the proximally facing counter stop face 134 provided, for example, at the proximal end of the projection 136 is in proximal end abutment with the distally facing retaining face 124 of the first recess 126 of the second profile structure 132.

[0173] When starting from an initial configuration as illustrated in Fig. 14, wherein the first elongated member 110 is in a first longitudinal position, and as the first elongated member 110 is moved along the distal direction 102 relative to the second elongated member 120, the stop face 114 at the first profile structure 112 exerts a force pointing distally onto the dose limiter 130. The distally facing side of the protrusion 136 comprises a bevel 138 through which the dose limiter 130 is allowed to smoothly slide out of the pocket or recess 126 in the distal direction 102 until the second profile section 132 engages with the consecutive retaining face 124' of the subsequent recess 126' of the second profile structure 122 as illustrated in Fig. 15.

[0174] Here, the first elongated member 110 has reached a second longitudinal position compared to the configuration illustrated in Fig. 14. In this position and due to the proximally facing counter stop face 134 of the dose limiter 130 being in longitudinal and proximal engagement with the distally facing second retaining face 124' of the second profile structure 122, the dose limiter 130 is hindered from returning to the proximal position as illustrated in Fig. 14. Rather, when the first elongated member 110 is moved back in the proximal direction 103, which movement can be caused or controlled by a trigger spring for example, the sawtooth profile 113 of the first profile structure 112 is allowed to slide along the first bevel side 137 of the dose limiter 130 facing the first elongated member 110. Then, as illustrated in Fig. 16, the first elongated member 110 is allowed to return proximally to the first longitudinal position, in which position the consecutive second stop face 114' of the consecutive tooth 118' is in axial abutment with the first profile section 131 of the dose limiter 130.

[0175] In fact, the proximally facing first counter stop face 133 of the dose limiter 130 can face the distally facing stop face 114' of the second tooth 118' of the first elongated member 110. Here, it is not required that the first counter stop face 133 and the stop face 114' are in direct longitudinal abutment. An axial or longitudinal gap can be provided which will be closed when the first elongated member 110 shall be moved in the distal direction 102 again, e.g. during a subsequent dose dispensing procedure.

[0176] Although not specifically illustrated, the dose limiter 130 as well as the first profile structure 112 and the second profile structure 122 can be shaped and arranged in such a way that the mutually corresponding bevels or side faces are allowed to slide relative to each other in the longitudinal direction. In detail, when in the configuration of Fig. 15, the flank portions 119 of the teeth 118' of the first elongated member 110 are allowed to slide along the bevel 137 of the dose limiter 130 in the proximal direction 103, while the dose limiter 130 is hindered from moving proximally by the engagement or abutment of the second profile section 132 with the second profile structure 122.

[0177] In the presently shown example, the first profile structure 112 is shown as a sawtooth profile 113, while the second profile structure 122 is implemented as a recessed profile 123 featuring a plurality of recesses 126 arranged equidistantly along the longitudinal direction. Generally, the dose limiter 130 can be implemented and configured in many different ways. There are conceivable configurations in which, for example, the dose limiter 130 comprises a recessed structure and in which the second profile structure 122 comprises a sawtooth profile. For some other examples, one of the first profile section 131 and the first profile structure 112 comprises a protrusion or a protruding sawtooth profile, while the other one of the first profile section 131 and the first profile structure 112 comprises a correspondingly shaped recessed profile.

[0178] The dose limiting mechanism 100 as shown in the sequence of Figs. 14 to 18 is generally applicable to a variety of injection devices in which the first elongated member 110 is subjected to a well-defined stepwise distally directed longitudinal movement relative to the second elongated member 120 during or in order to initiate a dose dispensing procedure, and in which the first elongated member is subjected to a return movement in proximal direction 103 at the end of the dose dispensing procedure. Each time the first elongated member 110 is subjected to a distally directed movement, for example initiated by pressing a trigger or trigger button 18 of the injection device 1, the dose limiter 130 is moved one step further. The step size is determined by the periodic or longitudinal dimension of the first profile structure 112 and the second profile structure 122 and the longitudinal distance between the first and second longitudinal positions of the first elongated member 110.

[0179] Generally, the total number of teeth or the total number of discontinuous stop or retaining surfaces provided on the first and / or second profile structure defines the total number of doses that can be injected or dispensed by the injection device 1.

[0180] In order to effectively limit or prohibit further use of the injection device after termination or handling of a permissible number of dose dispensing procedures, at least one end stop 115, 125 is provided on at least one of the first elongated member 110 and the second elongated member 120. One example of an end stop 125 is shown in Fig. 17. There, the end stop 125 is provided at or near the distal end of the second elongated member 120. The end stop 125 protrudes from the longitudinal direction of the second elongated member 120 in transverse radial direction inwardly and towards the first elongated member 110. The end stop 125 protrudes inwardly into the gap or interspace between the first elongated member 110 and the second elongated member 120.

[0181] The end stop 125 comprises a proximally facing abutment face 128 which is configured to abut with a correspondingly shaped distally facing abutment face 147 of the dose limiter 130. Once the stop configuration as illustrated in Fig. 17 has been reached, in which the abutment face 147 is engaged with the abutment face 128, any further distally directed movement of the dose limiter 130, initiated by a corresponding distally directed movement of the first elongated member 110, is effectively hindered. In this way, the first elongated member 110 cannot be moved further in the distal direction 102.

[0182] Generally, when the first elongated member 110 is in axial abutment or axial engagement with the trigger or trigger button 18 of the injection device 1, repeated pressing of the trigger or trigger button 18 in the distal direction 102 is effectively hindered and no further dose dispensing action can be performed using the injection device 1.

[0183] Another configuration of the end stop 115 is illustrated in Fig. 18. There, the end stop 115 is provided on the first elongated member 110. Also here, the end stop 115 protrudes inwardly into the gap or interspace between the first elongated member 110 and the second elongated member 120. The end stop 115 comprises a proximally facing abutment face 117 for engagement with a distally facing abutment face 147 of the dose limiter 130. Here and when the first elongated member 110 is axially or longitudinally connected to the trigger or trigger button 18 of the injection device 1, the mutual abutment of the corresponding abutment faces 117, 147 prevents and locks a return movement of the first elongated member 110 in the proximal direction 103 relative to the second elongated member 120 at the end of the final or last allowable dose dispensing procedure.

[0184] As a result, the trigger or trigger button 18 can be hindered from returning to the initial position in which it can be pressed by the user. The release of the trigger or trigger button 18 thus does not lead to the usual return movement of the trigger or trigger button in the proximal direction. Furthermore, an engager between the dose dial and the second elongated member 120, e.g. realized as a number sleeve, can permanently remain disengaged. In this way, the user will also be hindered from setting or dialling another dose of medicament.

[0185] In the further illustration of Figs. 19 to 23, the dose limiting mechanism 100 explained above in connection with Figs. 14 to 18 is implemented or integrated into the injection device 1 described and illustrated with respect to Figs. 1 to 13b.

[0186] Here, the drive sleeve 21 is implemented as the first elongated component 110, while the number sleeve 4 is implemented as the second elongated component 120. The second elongated component 120 can be in threaded engagement with the housing 3. The respective threads or thread sections are not specifically shown in Fig. 20. An outer thread 5 as an implementation of the second elongated component 120 of the number sleeve 4 is shown for example in Fig. 18. In contrast to the example of Figs. 1 to 13b, when the first elongated component 110 is implemented as the drive sleeve 21, it is devoid of an outer thread but comprises a sawtooth profile 113 featuring a series of distally facing annular abutment faces 114, 114', 114" as shown in Fig. 14.

[0187] For the example in Figs. 19 to 23, the dose limiter 130 is permanently rotationally locked to the second elongated component 120. To this end, the dose limiter 130 comprises at least one or a plurality of spline features 143 on the outer side surface which are in engagement with a correspondingly shaped spline feature 127 on the inside of the tubular second elongated component 120. The dose limiter 130 is longitudinally displaceable inside the second elongated component 120. As shown in Fig. 20, a recess profile 123 is implemented on or in the bottom of the spline feature 127 which is provided in the sidewall of the second elongated component 120.

[0188] The spline feature 127 comprises an elongated groove on the inside of the sidewall of the tubular second elongated component 120. The groove or spline feature 127 is further provided with a plurality of recesses 126, 126', 126" each providing a respective distally facing retaining face 124, 124', 124" in the distal direction 102. The dose limiter 130 comprises an annular ring 140. On the outer side surface 142, the spline features 143 are provided to be in engagement with the correspondingly shaped spline feature 127 of the second elongated component 120. On the spline features 143, the dose limiter 130 comprises at least one radially outwardly extending protrusion 136 which forms or constitutes a second profile section 132 to be in engagement with the second profile structure 122 provided by the recess profile 123 of the second elongated component 120. As shown in Fig. 21, the protrusion 136 comprises a proximally facing counter stop face 134 to be in engagement with the distally facing retaining faces 124, 124', 124" of the second profile structure 122. Generally, for other examples, the second profile section 132 can be located elsewhere on the outer side surface of the dose limiter 130. It can be arranged to be circumferentially offset from the spline features 143.

[0189] On the inner side surface 141 of the dose limiter, e.g. on the inner side of the ring 140, a gear ring 146 comprising a number of teeth 148 is provided. Each tooth 148 comprises or constitutes a first profile section 131 of the limiter 130. The teeth 148 are regularly arranged along the inner circumference of the ring 140. Each tooth 148 comprises a proximally facing first counter stop face 133 to engage with the sawtooth profile 113 provided on the outer side surface of the tubular first elongated member 110. In detail, the first counter stop faces 133 of the plurality of teeth 148 are configured to engage or abut in longitudinal direction with the distally facing stop faces 114, 114', 114" of the first profile structure 112. In this way, the dose limiter 130 can be dragged or pushed in distal direction 102 by the first elongated member 110 relative to the second elongated member 120, i.e. by the annular and distally facing stop faces 114 of the first profile structure 112. The stop faces 114 are in distally directed abutment with the first counter stop faces 133 of the respective first profile sections 131 of the dose limiter 130.

[0190] It is further apparent from Fig. 19 that the end stop 115 provided on the first elongated member 110 comprises a number of teeth 116. The teeth 116 are configured to be rotationally locked with the teeth 148 and thus with the gear ring 146 provided on the inner side surface 141 of the dose limiter 130. During dose setting and when located proximally of the end stop 115, the dose limiter 130 is free to rotate relative to the first elongated member 110. Due to the splined engagement with the second elongated member 120, the dose limiter 130 is rotated relative to the first elongated member 110 and thus relative to the drive sleeve 21 during dose setting.

[0191] The teeth 148 protruding radially inward from the inner side surface 141 of the dose limiter 130 comprise oppositely positioned flanks 139 as schematically illustrated in Figs. 21 and 23. The oppositely positioned flanks 139 are slightly symmetrical in circumferential direction. They merge with the bevel 137. As shown in Fig. 21, the flanks 139 converge in distal direction 102. This facilitates a rather smooth engagement with the teeth 116 of the end stop 115 when the respective stop configuration has been reached.

[0192] During dose setting, the drive sleeve 21 and thus the first elongated member 110 are rotationally locked to the housing 3 of the injection device 1, whereas the number sleeve 4 or scale barrel is subject to rotation. Now and when the dose limiter 130 is longitudinally aligned or longitudinally overlapping with the end stop 115, e.g. after the final or last dose dispensing action has been terminated, the gear ring 146 is rotationally locked to at least one locking tooth 116 provided on the outer side surface of the first elongated member 110 or drive sleeve 21. Due to this rotational interlock, the drive sleeve 21 will be rotationally locked to the number sleeve 4.

[0193] In this way and due to the rotational locking of the drive sleeve 21 to the housing 3, the number sleeve 4 and thus the dose dial 12 cannot be rotated further to set a dose. When the end of the dose configuration is reached and when the predetermined allowable number of doses has been dispensed by the injection device 1, the number sleeve 4 is rotationally locked to the drive sleeve 21 and any further use of the injection device 1 is effectively blocked and hindered.

[0194] List of reference signs

[0195] 1 injection device (drug delivery device)

[0196] 2 dose dial / dial grip

[0197] 3 housing / main body

[0198] 4 dose dial sleeve / number sleeve

[0199] 5 outer thread

[0200] 6 marker

[0201] 7 window

[0202] 8 longitudinal border

[0203] 9 longitudinal axis

[0204] 10 radial border

[0205] 11 sliding element

[0206] 12 sliding window

[0207] 13 recess

[0208] 14 drive spring

[0209] 15 extension

[0210] 16 distal end of sliding element

[0211] 17 proximal end of sliding element

[0212] 18 trigger button

[0213] 19 engager plate

[0214] 20 last dose nut

[0215] 21 drive sleeve

[0216] 22 engager spring

[0217] 23 lead screw

[0218] 24 bearing

[0219] 25 cartridge holder

[0220] 26 cartridge

[0221] 27 upper number sleeve portion

[0222] 28 lower number sleeve portion

[0223] 29 male threaded feature

[0224] 30 zero dose abutment of the sliding element

[0225] 31 maximum dose abutment of the sliding element

[0226] 32 zero dose abutment of the number sleeve

[0227] 33 maximum dose abutment of the number sleeve

[0228] 34 access port

[0229] 35 recess

[0230] 36 anchor

[0231] 37 hook

[0232] 38 closed loop

[0233] 39 open loop

[0234] 40 spline of the button

[0235] 41 spline of the number sleeve

[0236] 42 spline of the button

[0237] 43 spline of the drive sleeve

[0238] 44 spline of the main body

[0239] 45 helical tooth

[0240] 46 helical tooth

[0241] 47 spline of the adapter plate

[0242] 48 window

[0243] 49 revealable element

[0244] 50 spline on the main body

[0245] 51 spline on the drive sleeve

[0246] 52 spline on the number sleeve

[0247] 100 dose limiting mechanism

[0248] 102 Distal direction

[0249] 103 Proximal direction

[0250] 110 Slender component

[0251] 112 Profile Structure

[0252] 113 Serrated Profile

[0253] 114 Stop surface

[0254] 115 End stop

[0255] 116 Locking teeth

[0256] 117 Abutment Surface

[0257] 118 teeth

[0258] 119 Flanking section

[0259] 120 Slender Components

[0260] 122 Profile Structure

[0261] 123 Recessed Profile

[0262] 124 Maintain surface

[0263] 125 End stop

[0264] 126 recess

[0265] 127 Spline Features

[0266] 128 contact surface

[0267] 130 Dosage Limiter

[0268] 131 Profile Section

[0269] 132 Profile Section

[0270] 133 Reverse stop surface

[0271] 134 Reverse stop surface

[0272] 135 Protrusion

[0273] 136 Protrusion

[0274] 137 Hypotenuse

[0275] 138 Hypotenuse

[0276] 139 Flanking

[0277] 140 laps

[0278] 141 Inner surface

[0279] 142 Outer surface

[0280] 143 Spline Features

[0281] 146 Gear Ring

[0282] 147. Contact surface

[0283] 148 teeth

Claims

1. A dose limiting mechanism (100) for an injection device (1), the dose limiting mechanism (100) being configured to be disposed inside a housing (3) of the injection device (1) and operable to limit the total number of doses that can be dispensed by the injection device, the dose limiting mechanism (100) comprising: - A first elongated member (110) extending in the longitudinal direction and including a first profile structure (112), wherein the first profile structure (112) includes a plurality of stop surfaces (114, 114', 114") continuously arranged in the longitudinal direction and facing the distal direction. - A second elongated member (120), which is coaxial or parallel to the first elongated member (110) and includes a second profile structure (122) facing the first profile structure (112). A dose limiter (130) is disposed between the first elongated member (110) and the second elongated member (120), the dose limiter (130) comprising a first profile section (131) and a second profile section (132). - wherein the first profile segment (131) is capable of engaging with the first profile structure (112) to transmit longitudinal movement of the first elongated member (110) relative to the second elongated member (120) in the distal direction to the dose limiter (130) when the first elongated member (110) moves longitudinally in the distal direction during dose dispensing, and - wherein the second profile section (132) is capable of engaging with the second profile structure (122) to maintain the longitudinal position of the dose limiter (130) relative to the second elongated member (120) when the first elongated member (110) moves longitudinally relative to the second elongated member (120) in the proximal direction.

2. The dose limiting mechanism according to claim 1, wherein, The engagement of the first profile structure (112) with the first profile section (131) allows the first elongated member (110) to move proximally relative to the dose limiter (130), but prevents distal movement of the first elongated member relative to the dose limiter (130).

3. The dose-limiting mechanism according to claim 1 or 2, wherein, The engagement of the second profile structure (122) with the second profile section (132) allows the dose limiter (130) to move in the distal direction relative to the second elongated member (120) but is prevented from moving proximally relative to the second elongated member (120).

4. The dose limiting mechanism according to claim 1 or 2, wherein, The first profile section (131) includes a first reverse stop surface (133) facing the proximal direction (103) and configured to engage with the stop surface (114, 114', 114") of the first profile structure (112).

5. The dose limiting mechanism according to claim 1 or 2, wherein, The second profile structure (122) includes a plurality of retaining surfaces (124, 124', 124") arranged continuously in the longitudinal direction and facing the distal direction.

6. The dose limiting mechanism according to claim 5, wherein, The second profile section (132) includes a second reverse stop surface (134) facing the proximal direction and configured to engage with the retaining surfaces (124, 124', 124") of the second profile structure (122).

7. The dose limiting mechanism according to claim 1 or 2, wherein, The first profile structure (112) and the first profile section (131) provide a one-way ratchet, allowing and forcing distal movement of the first elongated member (110) to be transmitted to the dose limiter (130).

8. The dose limiting mechanism according to claim 1 or 2, wherein, The second profile section (132) and the second profile structure (122) provide a one-way ratchet that supports distal movement of the dose limiter (130) relative to the second elongated member (120) but prevents and blocks proximal movement of the dose limiter (130) relative to the second elongated member (120).

9. The dose limiting mechanism according to claim 1 or 2, wherein, The first elongated member (110) and the second elongated member (120) are rotatable relative to each other during dose setting, and wherein the first elongated member (110) and the second elongated member (120) are rotatably locked during dose dispensing.

10. The dose-limiting mechanism according to claim 1 or 2, wherein, The dose limiter (130) is rotatably locked to one of the first elongated member (110) and the second elongated member (120), and wherein the dose limiter (130) is rotatable relative to the other of the first elongated member (110) and the second elongated member (120).

11. The dose limiting mechanism according to claim 1 or 2, wherein, At least one of the first elongated member (110) and the second elongated member (120) includes an end stop (115, 125) configured to engage with the dose limiter (130).

12. The dose limiting mechanism according to claim 11, wherein, The end stop (115) of the first elongated member (110) is configured to prevent longitudinal movement of the first elongated member (110) relative to the dose limiter (130) or relative to the second elongated member (120) in a proximal direction when engaged with the dose limiter (130).

13. The dose-limiting mechanism according to claim 11, wherein, The end stop (125) of the second elongated member (120) is configured to prevent longitudinal movement of the first elongated member (110) relative to the dose limiter (130) or relative to the second elongated member (120) in a distal direction when engaged with the dose limiter (130).

14. The dose-limiting mechanism according to claim 11, wherein, The end stops (115, 125) and the dose limiter (130) are configured to rotate interlock when the dose limiter (130) overlaps with the end stops (115, 125) in the longitudinal direction.

15. The dose-limiting mechanism according to claim 14, wherein, One of the end stop (115) and the dose limiter (130) includes at least one locking tooth (116), and the other of the end stop (115) and the dose limiter (130) includes a gear ring (146) for rotatably engaging with the at least one locking tooth (116).

16. The dose limiting mechanism according to claim 1 or 2, wherein when the first elongated member (110) and the second elongated member (120) are arranged coaxially, the first elongated member (110) includes a tubular sleeve and the second elongated member (120) includes a tubular sleeve.

17. The dose-limiting mechanism according to claim 1 or 2, wherein, The dose limiter (130) includes one of a closed loop structure, an open loop structure, or a semi-circular structure.

18. The dose-limiting mechanism according to claim 1 or 2, wherein, The first elongated component (110) includes a drive sleeve (21) that is movable from a first longitudinal position to a second longitudinal position relative to the housing (3) of the injection device (1) along the distal direction, wherein, when in the first longitudinal position, the drive sleeve (21) is rotatably constrained to the housing (3), and wherein, when in the second longitudinal position, the drive sleeve (21) is freely rotatable relative to the housing (3).

19. The dose-limiting mechanism according to claim 1 or 2, wherein, The second elongated component (120) includes a digital sleeve (4) that rotates freely relative to the housing (3).

20. An injection device (1) for setting and dispensing a dose of a liquid medicine, the injection device (1) comprising: - A housing (3) for containing a cartridge (26) filled with the liquid medicine. - A lead screw (23) for operably engaging with the cartridge (26) to dispense a dose of the drug from the cartridge (26), - Dosage dial (2), used to set variable dosage, - Trigger (18) for triggering the dispensing of the dose, and - The dose limiting mechanism (100) according to any one of claims 1-19, wherein the first elongated member (110) of the dose limiting mechanism (100) is longitudinally engaged with the trigger (18), and wherein the second elongated member (120) of the dose limiting mechanism (100) is longitudinally constrained to the housing (3).

21. The injection device according to claim 20, further comprising the cartridge (26) filled with the liquid agent and disposed inside the housing (3).

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