Dose Delivery Mechanism

Abstract

1. A dose delivery mechanism comprising a piston rod and a nut, the piston rod forming an external thread that mates with the internal thread of the nut, and wherein, during setting of a dose, the nut is configured to rotate relative to the piston rod to advance the nut distally a first distance relative to the piston rod; a dose delivery mechanism comprising an actuating member that can be moved by a user to achieve delivery of a set dose, and a housing, wherein a second threaded connection is provided, the second threaded connection being configured to move the actuating member distally a second distance during setting of a dose, the actuating member being coupled to the piston rod via the nut during delivery of a dose, and wherein moving the actuating member proximally the second distance advances the piston rod proximally the first distance, the second distance being less than 1.5 times the first distance.

Description

[Technical field]

[0001] The present invention relates to dose delivery mechanisms such as injection pens.

[0002] Injection pens can be used to self-inject a specific amount of medication, i.e., a specific dose. To self-inject a medication, a patient must usually set the desired dose and then press an actuating member at the distal end of the injection pen in a proximal direction. Most pens use gear mechanisms with a gear ratio of 2-4 to reduce the force required to press the actuating member. Such pens are limited as to the amount of medication that a patient can self-inject in one actuation of the pen, since there is a maximum distance that the actuating member can be comfortably pressed with the thumb while holding the pen in one hand.

[0003] There is a need for a dose delivery mechanism that allows people to comfortably self-inject larger amounts of medication.

[0004] This problem is satisfied by a dose delivery mechanism comprising a piston rod and a nut, the piston rod forming an external thread that mates with the internal thread of the nut, and wherein, during setting of a dose, the nut is configured to rotate relative to the piston rod to advance the nut distally a first distance relative to the piston rod, wherein the dose delivery mechanism comprises an actuating member that can be moved by a user to achieve delivery of the set dose, and a housing, wherein a second threaded connection is provided, the second threaded connection being configured to move the actuating member distally a second distance during setting of a dose, and wherein, during delivery of a dose, the actuating member is coupled to the piston rod via the nut, and advances the piston rod proximally a first distance when the actuating member moves proximally a second distance, the second distance being less than 1.5 times the first distance.

[0005] The general idea behind the present invention is a dose delivery mechanism having a relatively small gear ratio that allows the delivery of relatively large amounts of drug with a relatively small axial movement of the actuating member.

[0006] The second threaded connection can have a constant pitch. The second threaded connection can act between the housing and the actuating member. The actuating member can be configured to follow a path defined by the second threaded connection during setting of a dose. Alternatively, the actuating member can be configured to move linearly a second distance when a separate member of the dose delivery mechanism follows a path defined by the second threaded connection during setting of a dose.

[0007] For example, the second threaded connection may act between the dose metering member and the housing of the dose setting mechanism, whereby the dose metering member may be configured to follow a path defined by the second threaded connection during setting of a dose. For example, the dose metering member may be directly engaged with the housing via the second threaded connection, such that the dose metering member and the housing form the second threaded connection. The dose metering member and / or the housing may be connected to the second threaded connection via one or more respective intermediate members, such as via an intermediate member that is axially and / or rotationally fixed relative to the dose metering member and / or via an intermediate member that is axially and / or rotationally fixed relative to the housing.

[0008] The actuating member may be configured to undergo both rotational and linear movement with the dose metering member in the distal direction during setting of a dose, or alternatively, the actuating member may be configured to undergo only linear, non-rotational movement with the dose metering member in the distal direction during setting of a dose.

[0009] The dose delivery mechanism may comprise a dose setting member configured to be gripped and manipulated, e.g. rotated, by a user to set the dose to be injected. For example, rotation of the dose setting member may cause relative rotation of two members, such as a housing and a dose setting member, which engage with each other via a second screw connection during setting of a dose. The dose setting member may be configured integrally with the actuation member, e.g. as a member that is rotated to set the dose to be injected and pushed proximally to achieve delivery of the set dose, or may be rigidly connected to the actuation member. Furthermore, the dose setting member may be configured separately from the actuation member, e.g. as a dose setting ring provided around the housing of the dose delivery mechanism.

[0010] The first distance is determined by the pitch of the first threaded connection between the piston rod and the nut, and the second distance is determined by the pitch of the second threaded connection. The first distance must correspond to the desired dispensed dose. When using a typical commercial cartridge with a nominal fill of 3 ml, the distance is about 14 mm to dispense 1.0 ml. The limit of the second distance is given by a usability assessment and may be, for example, 20 mm. Thus, if the maximum dispensed dose from the pen injector is 1 ml, the pitch of the second threaded connection is less than 1.4 times the pitch of the first connection. Additionally or alternatively, the minimum allowable value of the second pitch may be greater than the maximum allowable value of the first pitch, while the minimum allowable value of the second pitch is the minimum value that the second pitch can take within its manufacturing tolerances, and the maximum allowable value of the first pitch is the maximum value that the first pitch can take within its manufacturing tolerances.

[0011] The piston rod may be rotationally fixed relative to the housing during dose setting and / or delivery.

[0012] Embodiments of the dose delivery mechanism are defined by the dependent claims and described in the following disclosure.

[0013] According to one embodiment, the first distance is essentially equal to the second distance, which allows one to self-inject even larger amounts of drug while ensuring that the distance the actuation member must be pushed to inject that amount of drug is small enough that the actuation member can be pushed in a comfortable manner.

[0014] If the second distance and / or the pitch of the second screw connection is at most 1.01 times, in particular at most 1.005 times, the first distance and / or the pitch of the first screw connection, the first and second distances may be essentially equal.

[0015] The actuating member may be configured to push the piston rod proximally during delivery of the dose, either directly or via one or more intermediate members. For example, the actuating member may be configured to push a threaded member, such as a dose metering member connected to the housing via a second threaded connection, proximally during delivery of the dose, thus achieving rotation of the threaded member along the second threaded connection. The threaded member may then be configured to push the piston rod proximally, for example via an intermediate member, such as a nut. During delivery of the dose, the nut may be rotationally fixed relative to the piston rod, such that proximal movement of the nut results in proximal movement of the piston rod due to the mutual threaded connection.

[0016] The dose delivery mechanism may be configured to advance the piston rod proximally during dose delivery at the same rate that the actuation member moves distally during dose delivery.

[0017] During dose delivery, only a single threaded connection, such as the second threaded connection, can achieve guided axial and rotational relative movement between the members of the dose delivery device.

[0018] According to a further embodiment, all parts configured to rotate relative to the housing during dose delivery are connected to the housing via exactly one thread. "Connected to the housing via exactly one thread" means that all parts configured to rotate relative to the housing during dose delivery form a subassembly, which is connected to the housing via a single threaded connection. This means that there is no second threaded connection acting between the housing and the subassembly, i.e. connecting the housing and the subassembly. The pitch of the single threaded connection defines the axial distance that all rotating parts that rotate during dose delivery move in a given angular rotation. All parts configured to rotate relative to the housing during dose delivery may be axially and rotationally fixed to one another during dose delivery. During dose setting, one or more of these parts may be rotationally and / or axially movable relative to one or more of the other parts. In other embodiments, parts that rotate relative to the housing during dose delivery may be rotationally and axially fixed to one another during dose setting.

[0019] Components configured to rotate relative to the housing during dose delivery may include a driver, a dose sleeve, a dose metering member, and / or a snap element.

[0020] The exactly one thread may be, for example, a second threaded connection.

[0021] The dose delivery mechanism may have a dose setting unit with a dose metering member, which may be rotationally fixed to the dose setting member and / or the actuating member during setting of a dose. The dose metering member as well as the dose setting member and the actuating member may for example be rotatable in unison to set a desired dose. The dose metering member may be connected to the housing via a second screw connection.

[0022] The dose metering member may be rotationally decoupled from the dose setting member and / or the actuating member during delivery of a dose. The dose metering member may be configured to rotate relative to the housing during delivery of a dose. Additionally or alternatively, the dose setting member and / or the actuating member may be configured to be rotationally fixed relative to the housing during delivery of a dose.

[0023] The dose metering member may be configured to rotate relative to the housing during delivery of the dose. The dose metering member may be connected to the housing of the device via a second threaded connection during delivery of the dose. Proximal movement of the actuation member during delivery of the dose may cause the dose metering member to follow a path defined by the second threaded connection in the proximal direction.

[0024] The dose metering member may be configured to apply a force, such as a linear force in a proximal direction, to the piston rod during delivery of a dose. For example, the dose metering member may apply a force to the piston rod via a nut. The dose metering member may be configured to advance proximally during delivery of a dose, thereby abutting the nut. The nut and the piston rod may then be retracted proximally together with the dose metering member.

[0025] According to one embodiment, the dose delivery mechanism further comprises a dose setting unit having a dose sleeve indicating a set dose, rotationally coupled to the actuation member during setting of the dose. The actuation member and the dose sleeve may be rotatable to set the desired dose. Preferably, the actuation member and the dose sleeve are rotatable together to set the desired dose. The dose sleeve may be connected to the housing via a second screw connection.

[0026] The dose sleeve may constitute the dose metering member or may be part of the dose metering member that is axially and / or rotationally fixed to another part of the dose metering member.

[0027] According to one embodiment, the dose sleeve and the actuating member are rotationally decoupled during dose delivery, such that the actuating member does not rotate during dose delivery, which allows the actuating member to be comfortably pressed without friction between the thumb and the actuating member.

[0028] According to one embodiment, the dose delivery mechanism further comprises a driver, which exerts a force on the nut to drive the piston rod during delivery of the dose. The dose sleeve and the driver may form one part or may be rotationally and axially rigidly connected to each other. The dose sleeve and the driver may be part of the dose metering member.

[0029] According to a further embodiment, the driver directly abuts the nut to drive the piston rod during dose delivery, which allows the force applied to the driver to be transmitted directly to the nut.

[0030] According to one embodiment, the driver is rotated relative to the housing during delivery of the dose, this rotational movement being preferably caused by the second threaded connection.

[0031] According to a further embodiment, the dose delivery mechanism comprises a spring acting between the housing and the actuation member during setting of the dose. The spring may be provided between the housing and the dose sleeve or between the housing and the driver.

[0032] Additionally or alternatively, a spring may act between the housing and the dose metering member.

[0033] Preferably, the spring is configured to assist the user in moving the actuating member to achieve delivery of the set dose, thereby ensuring that the patient requires less force to inject the set dose. To ensure that the spring assists in moving the actuating member to the end of the injection, the spring may be preloaded in the as-delivered state, i.e. when the pen is delivered to the user.

[0034] The spring may be a torsion spring. If the torsion spring is a helical torsion spring, a large assist force can be obtained. Preferably, the spring is configured to be tensioned during setting of a dose. In other words, the spring is preferably arranged within the dose delivery mechanism such that rotational movement of a dose setting knob, e.g. an actuation member, causes the spring to be tensioned or further tensioned.

[0035] According to one embodiment, the spring is coupled to a piston rod guide and driver that guides the linear motion of the piston rod. The piston rod guide may be part of the housing or may be fixedly coupled to the housing.

[0036] Preferably, the spring is located in a proximal part, in particular in a proximal end part, of the dose delivery mechanism. The dose delivery mechanism, e.g. a unit for setting and delivering a set dose, can be coupled to a drug preparation unit, such as a unit intended for mixing a lyophilized drug with a solvent before use, i.e. a reconstitution unit. It is also possible to couple to a unit with a cartridge already containing the drug ready to be used.

[0037] According to one embodiment the actuating member is rotationally fixed to the nut during dose setting and dose delivery, the actuating member may comprise longitudinally extending torque transmitting means of the nut, for example longitudinally extending ribs mating with longitudinally extending grooves.

[0038] According to another embodiment, the driver and a part of the housing, in particular the piston rod guide, form the second threaded connection. Preferably, the driver and an inner housing part, in particular an inner housing part arranged radially inside the dose sleeve, form the second threaded connection. In general, any part that can be rotated during dose delivery, in particular a part that can be rotated during dose setting and dose delivery, such as the dose sleeve or the driver, and any part that cannot be rotated relative to the housing during dose delivery can form the second threaded connection.

[0039] According to one embodiment, the piston rod is linearly guided in the housing. Alternatively or additionally, the piston rod may be non-rotatably attached to the housing, i.e. non-rotatably supported by the housing. In order to support the piston rod in such a way that it is linearly, but non-rotatably guided in the housing, the housing, in particular the piston rod guide, can have a longitudinal through opening with a non-circular inner circumference that corresponds to the non-circular outer circumference of the piston rod.

[0040] A ball bearing can be provided to reduce friction during dose delivery. The bearing can be disposed between the driver and the nut to reduce friction between the driver and the nut. Alternatively or additionally, a washer can be disposed between the driver and the nut, the washer being made of a low friction material, for example PTFE. Prior to the development of this dose delivery mechanism, it was believed that a gear ratio of more than 2 was necessary to allow the user to comfortably inject the set dose. However, the improvements described above and below make it possible to provide a dose delivery mechanism having a gear ratio of less than 2, or even less than 1.5, but still allowing the user to comfortably inject the set dose.

[0041] According to one embodiment, the velocity of the actuating member during delivery of the dose v am and the piston rod velocity v prIn other words, preferably the actuation member and the piston rod move simultaneously at the same speed in the proximal direction during delivery of the dose.

[0042] According to one embodiment, the nut is configured not to rotate relative to the housing and / or piston rod during delivery of the dose.

[0043] These and other features, aspects, and advantages are described below with reference to the drawings, in which like reference characters refer to corresponding features consistently throughout the drawings, and in which the embodiments shown in the drawings can be modified in numerous ways without departing from the invention. [Brief description of the drawings]

[0044] [Figure 1] 1 shows an exploded view of an injection pen according to the present invention; [Figure 2A] 2 shows a perspective view of a knob cover of the injection pen of FIG. 1; [Figure 2B] FIG. 2B shows a side view of the knob cover of FIG. 2A. [Figure 2C] 2C shows a cross-sectional view of the knob cover of FIG. 2B taken along line AA of FIG. 2B. [Figure 3A] 2 shows a perspective view of an injection button of the injection pen of FIG. 1; [Figure 3B] FIG. 3B shows a side view of the injection button of FIG. 3A. [Figure 3C] 3B shows a cross-sectional view of the injection button of FIG. 3B along line AA of FIG. 3B. [Figure 3D] 3B shows a cross-sectional view of the injection button of FIG. 3B along line BB of FIG. 3B. [Figure 3E] 3C shows a cross-sectional view of the injection button of FIG. 3B along line CC of FIG. 3B. [Figure 4A] 2 shows a perspective view of a snap ring of the injection pen of FIG. 1; [Figure 4B] FIG. 4B shows a top view of the snap ring of FIG. 4A. [Figure 4C]FIG. 4B shows a side view of the snap ring of FIG. 4A. [Figure 4D] FIG. 4B shows a bottom view of the snap ring of FIG. 4A. [Figure 5A] 2 shows a first perspective view of the dose setting knob of the injection pen of FIG. 1; [Figure 5B] FIG. 5B shows a second perspective view of the dose setting knob of FIG. 5A. [Figure 5C] FIG. 5B shows a side view of the dose setting knob of FIG. [Figure 5D] 5C shows a cross-sectional view of the dose setting knob of FIG. 5A along line AA of FIG. 5C. [Figure 6A] 2 shows a perspective view of a snap element of the injection pen of FIG. 1; [Figure 6B] 6B shows a side view of the snap element of FIG. 6A. [Figure 6C] 6B shows a cross-sectional view of the snap element of FIG. 6A along line AA of FIG. 6B. [Figure 7A] 2 shows a perspective view of the connector of the injection pen of FIG. 1; [Figure 7B] FIG. 7B shows a bottom view of the connector of FIG. 7A. [Figure 7C] 7B shows a side view of the connector of FIG. 7A. [Figure 7D] 7B shows a top view of the connector of FIG. 7A. [Figure 8A] 2 shows a first perspective view of a dose selector of the injection pen of FIG. 1; [Figure 8B] FIG. 8B shows a bottom view of the dose selector of FIG. 8A. [Figure 8C] FIG. 8B shows a side view of the dose selector of FIG. 8A. [Figure 8D] 8C shows a cross-sectional view of the dose selector of FIG. 8A along line AA of FIG. 8C. [Figure 8E] 8C shows a cross-sectional view of the dose selector of FIG. 8A along line BB of FIG. 8C. [Figure 9] FIG. 8B shows a second perspective view of the dose selector of FIG. 8A. [Figure 10A] 2 shows a perspective view of a knob key of the injection pen of FIG. 1; [Figure 10B] FIG. 10B shows a side view of the knob key of FIG. 10A. [Figure 11A] 2 shows a perspective view of the housing of the injection pen of FIG. 1; [Figure 11B] FIG. 11B shows a side view of the housing of FIG. 11A. [Figure 11C] 11B shows a cross-sectional view of the housing of FIG. 11A taken along line AA of FIG. [Figure 12A] 2 shows a first side view of the dose setting sleeve of the injection pen of FIG. 1; [Figure 12B] FIG. 12B shows a second side view of the dose setting sleeve of FIG. 12A. [Figure 12C] FIG. 12B shows a third side view of the dose setting sleeve of FIG. 12A. [Figure 12D] FIG. 12B shows a fourth side view of the dose setting sleeve of FIG. 12A. [Figure 12E] 12B shows a front view of the dose setting sleeve of FIG. 12A. [Figure 12F] 12B shows a first perspective view of the dose setting sleeve of FIG. 12A. [Figure 12G] A second perspective view of the dose setting sleeve of Figure 12A is shown. [Figure 13A] 2 shows a perspective view of a driver of the injection pen of FIG. 1; [Figure 13B] FIG. 13B shows a first side view of the driver of FIG. 13A. [Figure 13C] FIG. 13B shows a second side view of the driver of FIG. 13A. [Figure 13D] 13C shows a cross-sectional view of the driver of FIG. 13A taken along line AA of FIG. 13C. [Figure 14A] 2 shows a first perspective view of the nut of the injection pen of FIG. 1; [Figure 14B] FIG. 14B shows a second perspective view of the nut of FIG. 14A. [Figure 14C] FIG. 14B shows a side view of the nut of FIG. 14A. [Figure 14D] 14C shows a first cross-sectional view of the nut of FIG. 14A taken along line AA of FIG. 14C. [Figure 14E]14C shows a second cross-sectional view of the nut of FIG. 14A taken along line BB of FIG. 14C. [Figure 15A] FIG. 2 shows a first side view of the piston rod guide of the injection pen of FIG. 1; [Figure 15B] FIG. 15B shows a second side view of the piston rod guide of FIG. 15A. [Figure 15C] 15B shows a cross-sectional view of the piston rod guide of FIG. 15A taken along line AA of FIG. 15A. [Figure 15D] FIG. 15B shows a perspective view of the piston rod guide of FIG. 15A. [Figure 16A] FIG. 15B shows a first longitudinal cross-sectional view of the piston rod guide of FIG. 15A. [Figure 16B] FIG. 15B shows a second longitudinal cross-sectional view of the piston rod guide of FIG. 15A. [Figure 16C] FIG. 15B shows a perspective view of the piston rod guide of FIG. 15A. [Figure 17A] 2 shows a side view of the piston rod of the injection pen of FIG. 1; [Figure 17B] 17B shows a cross-sectional view of the piston rod of FIG. 17A taken along line AA of FIG. 17A. [Figure 17C] FIG. 17B shows a first perspective view of the piston rod of FIG. 17A. [Figure 17D] FIG. 17B shows a second perspective view of the piston rod of FIG. 17A. [Figure 18A] FIG. 2 shows a perspective view of the piston disc of the injection pen of FIG. 1; [Figure 18B] FIG. 18B shows a top view of the piston disc of FIG. 18A. [Figure 18C] 18B shows a cross-sectional view of the piston disc of FIG. 18A along line AA of FIG. 18B. [Figure 19A] 2 shows a perspective view of a dual chamber cartridge of the injection pen of FIG. 1; [Figure 19B] FIG. 19B shows a side view of the dual chamber cartridge of FIG. 19A. [Figure 19C] 19B shows a cross-sectional view of the dual chamber cartridge of FIG. 19A along line AA of FIG. 19B. [Figure 20A] 2 shows a perspective view of a cartridge receptacle of the injection pen of FIG. 1; [Figure 20B] FIG. 20B shows a first side view of the cartridge receptacle of FIG. 20A. [Figure 20C] FIG. 20B shows a second side view of the cartridge receptacle of FIG. 20A. [Figure 20D] 20C shows a cross-sectional view of the cartridge receptacle of FIG. 20A taken along line AA of FIG. 20C. [Figure 21A] 2 shows a first perspective view of a cartridge key of the injection pen of FIG. 1; [Figure 21B] FIG. 21B shows a second perspective view of the cartridge key of FIG. 21A. [Figure 21C] FIG. 21B shows a first side view of the cartridge key of FIG. 21A. [Figure 21D] FIG. 21B shows a second side view of the cartridge key of FIG. 21A. [Figure 22A] FIG. 21B shows a third side view of the cartridge key of FIG. 21A. [Figure 22B] 22A shows a cross-sectional view of the cartridge key of FIG. 21A taken along line AA of FIG. 22A. [Figure 23A] FIG. 2 shows a side view of the injection pen of FIG. 1 as delivered. [Figure 23B] 23B shows a cross-sectional view of the injection pen of FIG. 23A taken along line AA of FIG. 23A. [Figure 24] 23B shows a perspective view of the injection pen of FIG. 23A without the knob cover and with some parts shown transparent. [Figure 25A] FIG. 23B shows a second side view of the injection pen of FIG. 23A. [Figure 25B] 25A shows a cross-sectional view of the injection pen of FIG. 23A taken along line AA of FIG. 25A. [Figure 26A] 2 shows a side view of the injection pen of FIG. 1 in a reconstituted state. [Figure 26B] 26B shows a cross-sectional view of the injection pen of FIG. 26A taken along line AA of FIG. 26A. [Figure 27A]FIG. 26B shows a second side view of the injection pen of FIG. 26A. [Figure 27B] FIG. 26B shows a third side view of the injection pen of FIG. 26A. [Figure 27C] 27B shows a cross-sectional view of the injection pen of FIG. 26A taken along line AA of FIG. 27B. [Figure 28A] 2 shows a side view of the injection pen of FIG. 1 with the knob cover unlocked; [Figure 28B] 28B shows a cross-sectional view of the injection pen of FIG. 28A taken along line AA of FIG. 28A. [Figure 29A] 2 shows a side view of the injection pen of FIG. 1 at the end of the reconstituted state. [Figure 29B] 29B shows a cross-sectional view of the injection pen of FIG. 29A taken along line AA of FIG. 29A. [Figure 30A] FIG. 2 shows a side view of the injection pen of FIG. 1 in a post-dose state. [Figure 30B] 30B shows a cross-sectional view of the injection pen of FIG. 30A taken along line AA of FIG. 30A. [Figure 31A] 2 shows a side view of the injection pen of FIG. 1 at the start of an injection state. [Figure 31B] 31B shows a cross-sectional view of the injection pen of FIG. 31A taken along line AA of FIG. 31A. [Figure 32A] 2 shows a further side view of the injection pen of FIG. 1 at the start of an injection state. [Figure 32B] 32B shows an enlarged cross-sectional view of the injection pen of FIG. 32A taken along line AA of FIG. 32A. [Figure 33A] 2 shows a side view of the injection pen of FIG. 1 at the end of the injection state. [Figure 33B] 33B shows a cross-sectional view of the injection pen of FIG. 33A taken along line AA of FIG. 33A. [Diagram 34] 1 shows a second injection pen according to the present disclosure in a pre-assembled state. [Diagram 35] 1 shows another view of the second injection pen in a pre-assembled state. [Diagram 36] 1 shows an exploded view of a second injection pen. [Figure 37]1 shows a longitudinal section of a second injection pen in a pre-assembled state. [Figure 38] FIG. 2 shows a detailed view of the distal portion of the second injection pen in a pre-assembled state. [Figure 39] FIG. 2 shows a detailed view of the distal end of the second injection pen in an assembled state during dose setting. [Diagram 40] 1 shows another view of the distal end of the second injection pen in an assembled state during dose setting. [Diagram 41] FIG. 2 shows a detailed view of the distal end of the second injection pen in an assembled state during dose delivery. [Diagram 42] 13 shows another view of the distal end of the second injection pen in an assembled state during dose delivery. [Diagram 43] 1 shows a longitudinal cross-sectional view of a dose setting element of a first and a second injection pen; [Diagram 44] 1 shows a perspective view of a longitudinal section of a dose setting element. [Diagram 45] FIG. 2 shows a perspective view from the distal side of the dose setting element. [Figure 46] FIG. 2 shows a perspective view from the proximal side of the dose setting element. [Figure 47] 1 shows a perspective view of a third injection pen according to the present disclosure. [Figure 48] 1 shows an exploded view of a third injection pen. [Figure 49] 13 shows a longitudinal cross-sectional view of the dose delivery mechanism of a third injection pen. [Figure 50] 13 shows a distal perspective view of the dose metering member of the third injection pen. [Figure 51] 13 shows a longitudinal section through the dose metering member of a third injection pen; [Figure 52] 13 shows a perspective view of a piston rod of a third injection pen. [Diagram 53] 13 shows a distal perspective view of an extension of a third injection pen. [Figure 54] FIG. 54 illustrates a distal view of the extension shown in FIG. 53. [Figure 55]FIG. 54 illustrates a proximal view of the extension shown in FIG. 53. [Figure 56] 13 shows a perspective view of a coupling element of a third injection pen. [Figure 57] 13 shows a perspective view of the bearing, piston rod, extension, coupling element and adjustment element of a third injection pen. [Figure 58] 13 shows a proximal perspective view of the adjustment element of the third injection pen. [Figure 59] 13 shows a side view of a control element of a third injection pen. [Figure 60] 59 shows a cross-sectional view of the third injection adjustment element along line AA in FIG. 59. [Figure 61] 59 shows a cross-sectional view of the third injection adjustment element along line BB in FIG. 59. [Figure 62] 13 shows a perspective view of a coupling member of a third injection pen. [Figure 63] 13 shows a distal perspective view of the sleeve of a third injection pen. [Figure 64] 13 shows a longitudinal cross-sectional view of a sleeve of a third injection pen. [Figure 65] 13 shows a perspective view of a housing insert of a third injection pen. [Figure 66] 13 shows a perspective view of a connector of a third injection pen. [Figure 67] 13 shows a perspective view of a longitudinal section of a connector of a third injection pen. [Figure 68] FIG. 2 shows a side view of the third injection pen in an assembled state during dose setting. [Figure 69] 1 shows a side view of a third injection pen in a pre-assembled state. [Figure 70] FIG. 2 shows a detailed view of a longitudinal section of the distal end of the third injection pen in an assembled state during dose setting. [Figure 71] FIG. 2 shows a further detailed longitudinal section of the distal end of the third injection pen in the assembled state during dose setting. [Figure 72]FIG. 2 shows a detailed view of a longitudinal section of the distal end of the third injection pen in an assembled state during dose delivery. [Figure 73] FIG. 13 shows a further detailed longitudinal section view of the distal end of the third injection pen in an assembled state during dose delivery. [Figure 74] 1 shows a detailed view of a longitudinal section of the distal end of a third injection pen in a pre-assembled state. [Figure 75] 1 shows a further detailed longitudinal section of the distal end of the third injection pen in a pre-assembled state. [Figure 76] 1 shows a perspective view of a fourth injection pen according to the present disclosure. [Figure 77] FIG. 2 shows a side view of the fourth injection pen in an assembled state during dose setting. [Figure 78] FIG. 13 shows a side view of the fourth injection pen in a pre-assembled state with the adjustment element in a pre-assembled position. [Figure 79] FIG. 13 shows a side view of the fourth injection pen in a pre-assembled state with the adjustment element in the adjustment position. [Figure 80] 1 shows an exploded view of a fourth injection pen. [Figure 81] FIG. 2 shows a longitudinal cross-sectional view of the dose delivery mechanism of the fourth injection pen in an assembled state during dose setting. [Figure 82] 13 shows a perspective view of a coupling element of a fourth injection pen. [Figure 83] 83 shows a cross-sectional view of the joining element shown in FIG. 82 taken along line AA. [Figure 84] FIG. 13 shows a perspective view of the piston rod of the fourth injection pen. [Figure 85] 13 shows a proximal perspective view of the adjustment element of the fourth injection pen. [Figure 86] 13 shows a side view of the adjustment element of the fourth injection pen. [Figure 87] 87 shows a first longitudinal cross-sectional view of the adjustment element along line AA in FIG. 86. [Figure 88]87 shows a further side view of the adjustment element of the fourth injection pen in a direction perpendicular to the direction of FIG. 86. [Figure 89] 89 shows a second longitudinal cross-sectional view of the adjustment element along line BB in FIG. 88. [Figure 90] 13 shows a distal perspective view of the sleeve of the fourth injection pen. [Figure 91] 1 shows a perspective view from the distal side of the sleeve insert. [Figure 92] 13 shows a proximal perspective view of the sleeve insert. FIG. [Figure 93] 1 shows a distal perspective view of the outer portion of the sleeve. [Figure 94] 13 shows a side view of a coupling member of a fourth injection pen. [Figure 95] 91 is a longitudinal cross-sectional view of the coupling member taken along line AA in FIG. 90. [Figure 96] 91 is a cross-sectional view of the coupling member taken along line BB in FIG. 90. [Figure 97] 13 shows a distal perspective view of the dose metering member of the fourth injection pen. [Figure 98] FIG. 2 shows a perspective view of a longitudinal section of the dose metering member; [Figure 99] 1 shows a longitudinal cross-sectional view of the distal end of the dose delivery mechanism of the fourth injection pen in an assembled state during dose setting. [Figure 100] 13 shows a further longitudinal cross-sectional view of the distal end of the dose delivery mechanism of the fourth injection pen in the assembled state during dose setting. [Figure 101] 1 shows a longitudinal cross-sectional view of the distal end of the dose delivery mechanism of the fourth injection pen in an assembled state during dose delivery. [Figure 102] 13 shows a further longitudinal cross-sectional view of the distal end of the dose delivery mechanism of the fourth injection pen in the assembled state during dose delivery. [Figure 103] FIG. 2 shows a longitudinal cross-sectional view of the distal end of the dose delivery mechanism of the fourth injection pen in a pre-assembled state with the adjustment element in a pre-assembled position. [Figure 104]FIG. 2 shows a further longitudinal cross-sectional view of the distal end of the dose delivery mechanism of the fourth injection pen in a pre-assembled state with the adjustment element in a pre-assembled position. [Figure 105] FIG. 2 shows a longitudinal cross-sectional view of the distal end of the dose delivery mechanism of the fourth injection pen in a pre-assembled state with the adjustment element in the adjusted position. [Figure 106] FIG. 2 shows a further longitudinal cross-sectional view of the distal end of the dose delivery mechanism of the fourth injection pen in the pre-assembled state with the adjustment element in the adjusted position. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0045] The components of an injection pen 10 according to the present invention will now be described with reference to Figures 1 to 22B, followed by a description of how the pen is intended to be used with reference to Figures 23A to 33B.

[0046] 1 shows an exploded view of a medication delivery device in the form of an injection pen 10. The injection pen 10 comprises, from the distal end 12 to the proximal end 14, a knob cover 16, which may also be referred to as a knob lock, cover or retaining element, an injection button 18, which may be part of an actuation member, a snap ring 20, a dose setting knob 22, which may also be referred to as a dose setting element, dose adjustment member or knob and may be part of an actuation member, a snap element 24, which may also be referred to as a dose setting device, a connector 26, a dose selector 28, a knob key 30, which may also be referred to as a clip, a housing 32, which may also be referred to as a body, a dose setting sleeve 34, which may also be referred to as a dose sleeve or dose indicating member, a driver 36, a nut 38, a spring 40, a piston rod guide 42, which may also be referred to as a piston guide, a piston rod 44, a piston disc 46, which may also be referred to as a bearing, a dual chamber cartridge 48, which may also be referred to as a medication container, fluid compartment or cartridge, a cartridge receptacle 50, and a cartridge holder or cartridge key 52. The combination of cartridge container 50 and cartridge holder 52 may be referred to as a medical container holder, whereby cartridge container 50 provides an outer container holder and cartridge key 52 provides an inner container holder of the container holder.

[0047] Although the above-mentioned components of the injection pen 10 may each be formed as separate components to simplify the manufacture of the separate components, it is generally contemplated that one or more of the components may be integrally formed with one another. For example, the injection button 18, the snap ring 20, and / or the dose setting knob 22 may be integrally formed with one another. Additionally, the dose setting sleeve 34 and the driver 36 may be integrally formed with one another. Generally, even the housing 32 and the piston rod guide 42 may be integrally formed with one another.

[0048] Different parts can be grouped together to define various functional units. For example, the part between the injection button 18 and the piston rod guide 42 can be referred to as the dose setting mechanism 54, the dose setting unit, the dose delivery mechanism, and / or the dose delivery actuation mechanism. On the other hand, the part between the piston rod guide 42 and the cartridge key 52 can be referred to as the drug reconstitution unit 56 or the reconstitution means. The cartridge container 50 and the cartridge holder 52 can be referred to as the cartridge holding unit. The cartridge container 50, the cartridge holder 52, and the cartridge 48 can be referred to as the cartridge unit. For example, the cartridge unit can be sold separately from the rest of the injection pen 10, either preassembled or as a separate part.

[0049] The above-mentioned components of the injector pen 10 will now be described in order, beginning with the distal end 12 and ending with the proximal end 14, which are the opposing ends of the injector pen 10, the proximal end 14 including the delivery outlet.

[0050] 2A-2C show the knob cover 16, which covers the dose setting knob 22 during delivery or transport of the injection pen 10 to a customer, such as a patient. The knob cover 16 is completely removable from the remainder of the injection pen 10. The knob cover 16 is attachable to and / or removable from the housing 32 via two deformable wings 58 that can be deflected outwardly, i.e. radially, to remove the knob cover 16 from the housing 32. The wings 58 form a proximal end portion of the knob cover 16. On the inner surface of each wing 58, form-fit engagement means in the form of lugs 60 are provided, which are adapted to engage the housing 32, and in particular to engage radially extending coupling surfaces 228 (see FIG. 15C) formed on the piston guide 42, to axially secure the knob cover 16 relative to the housing 32 in the distal direction. Adjacent each lug 60, a window 62, i.e., a radially extending opening, is formed in the wing 58. When the knob cover 16 is attached to the housing 32, the window 62 is located in an axial position where the housing 32 forms a circumferentially extending ridge 64 (see FIG. 25A). At the distal side of each window 62, i.e., away from the lug 60, an abutment portion 66 is formed on the inner surface of the respective wing 58. The abutment portion 66 has a width that corresponds to the width of a recess or notch 68 (see FIG. 11A) in the outer surface of the housing 32, more precisely, in a chamfered portion 69 formed in the outer surface of the housing 32. Furthermore, the abutment portion 66 forms a front surface 66a that axially abuts against a radially extending surface 32a (see FIG. 11B) that defines the proximal end of the notch 68 when the knob cover 16 is attached to the housing 32. Radially extending surface 32a defines a stop surface that terminates proximal movement of knob cover 16 relative to housing 32, for example, if injection pen 10 is dropped distal end 12 first on the floor. To further ensure that knob cover 16 does not move in the proximal direction 1 beyond its attached position, an axial abutment ridge 70 (see FIG. 11A) may be formed on the exterior surface of housing 32.The ridge 70 is configured to engage with a gap 72 (see FIG. 2C) formed between the wings 58 such that the proximal front surface of the knob cover 16 abuts the distal front surface of the axial abutment ridge 70.

[0051] The form-fitting engagement between the abutment portion 66 and the notch 68 and / or the form-fitting engagement between the ridge portion 70 and the gap 72 ensures that the knob cover 16 is rotationally restrained relative to the housing 32 when the knob cover 16 is attached to the housing 32.

[0052] As can be seen from Fig. 2A, the knob cover 16 can be removed from the rest of the injection pen 10 only by linearly moving the knob cover 16 in a distal direction. To do so, a linear recess 74 is formed on the inner circumferential surface of the knob cover 16, which corresponds to an anti-rolling means 76 (see Fig. 5B) of the dose setting knob 22 in the form of an axially extending rib. The dose setting knob 22 is thus prevented from rotating inside the knob cover 16 by form-fitting engagement of the linear recess 74 with the anti-rolling means 76. Furthermore, the knob cover 16 forms an anti-rolling means 78 in the form of an axially extending rib on the outer surface of the knob cover 16, as can be seen in Fig. 2A. The anti-rolling means 76 and 78 ensure that the injection pen 10 and the knob cover 16 do not roll when placed on a flat surface. As can also be seen from Fig. 2A, the knob cover 16 has a closed periphery 16a and a closed face 16b at the distal end. The knob cover 16 thus forms a closed sleeve around the distal portion of the injection pen 10 .

[0053] Figures 3A-3E show the injection button 18. The injection button 18 forms a distal front surface 80 for applying a force to the injection button 18 to inject the set dose. The injection button 18 comprises axial fixing means 82 for axially mounting the injection button 18 to a snap ring 20 (see Figures 4A-4D) axially connected to a dose setting knob 22 (see Figures 5A-5D). The axial fixing means 82 comprises two elastically deformable hooks 82 which engage with circumferentially extending ribs 84 on the snap ring 20. Furthermore, the snap ring 20 comprises axial fixing means 86 in the form of elastically deformable bendable hooks which engage with undercuts 88 formed in the dose setting knob 22. The injection button 18, the snap ring 20 and the dose setting knob 22 are permanently axially fixed to one another in the assembled state of the dose delivery mechanism 54.

[0054] Furthermore, the injection button 18 forms rotational locking means 90 in the form of radially extending ribs which engage by form-fitting with rotational locking means 92 in the form of teeth (see FIG. 4A) arranged on the inner circumferential surface of the snap ring 20 in order to rotationally connect the injection button 18 to the snap ring 20. The rotational locking means 92 forms a toothed portion 93 of the snap ring 20 and the ribs 90 form an engagement portion of the injection button 18. The snap ring 20 defines the flanks of the elastically deformable bendable hook 86 and comprises a rotational locking means 94 in the form of an axially extending recess which engages with a rotational locking means 96 in the form of an axially extending rib (see FIG. 5A) on the inner circumferential surface of the dose setting knob 22.

[0055] In the assembled state after assembly of the dose delivery mechanism 54, the injection button 18, the snap ring 20 and the dose setting knob 22 are rigidly connected to each other and form both the dose setting member and the actuation member of the dose delivery mechanism 54.

[0056] The injection button 18 forms a cylindrical portion 18a, on which assembly means 98 in the form of a ridge are formed for axially preassembling the injection button 18 with the snap element 24. More precisely, the lower, i.e. proximal, assembly means 98b (see FIG. 3C) limit the distal movement of the injection button 18 relative to the snap element 24 by interfering with the coupling means 102 on the snap element 24. The upper, i.e. distal, assembly means 98a limits the proximal movement of the injection button 18 relative to the snap element 24 after preassembly by interfering with the coupling means 102 on the snap element 24 and limits the distal movement of the injection button 18 after final assembly. When the snap element 24 and the injection button 18 are preassembled, i.e. in the preassembled state, the coupling means 102 is located between the proximal assembly means 98b and the distal assembly means 98a. In said preassembled state, the injection button 18 is not yet rigidly connected to the snap ring 20 and the dose setting knob 22. However, when the coupling means 102 is arranged distal to the distal assembly means 98a, i.e. in the assembled state, the injection button 18 is rigidly connected to the snap ring 20 and to the dose setting knob 22. Furthermore, the injection button 18 forms a coupling means 100 in the form of a protrusion arranged on the outer circumferential surface of the injection button 18 at a resiliently inwardly bendable portion, which extends axially and is partially surrounded by a notch 101.

[0057] The coupling means 100 is configured to permanently axially lock the injection button 18, and thus also the snap ring 20 and the dose setting knob 22, to the snap element 24 after the injection is completed, rendering the injection pen 10 inoperable. That is, when the injection button 18 moves axially to initiate the delivery of the dose, the coupling means 100 passes a radially inwardly extending coupling means in the form of a circumferentially extending ledge 102 (see FIG. 6A) on the snap element 24. The radially inwardly extending ledge 102 bends inwardly a protrusion arranged on the elastically inwardly bendable portion 100 until the protrusion passes the ledge 102. To reduce the force required to push the protrusion 100 past the ledge 102, the protrusion 100 forms a chamfered outer surface 100a. Alternatively or additionally, the ledge 102 may form a chamfered inner surface. Once the projections 100 clear the ledge 102, the projections 100 spring back to their neutral position, thereby permanently axially locking the injection button 18 to the snap element 24. This feature ensures that the injection pen 10 can only be used once to inject exactly one dose.

[0058] As best seen in Figures 3C and 3E, the injection button 18 includes an axially extending rib 104 on its inner circumferential surface. The axially extending rib 104 engages an axially extending groove 106 (see Figure 14C) in the nut 38 to form a rotational locking means. The axially extending rib 104 and corresponding axially extending groove 106 allow the injection button 18 and the nut 38 to move axially relative to each other, but are rotationally fixed relative to each other.

[0059] As can be best seen in Figures 5B and 5D, the dose setting knob 22 is provided with a set of teeth 108 on its inner axial portion. These teeth 108 are adapted to mesh with a set of teeth 110 arranged on a distal portion of the outer circumferential surface of the snap element 24 (see Figures 6A-6C) during dose setting. Thus, when the dose setting knob 22 is rotated during dose setting, the snap element 24 is also rotated. As can be seen in Figure 6A, the teeth 110 are arranged only on two oppositely facing portions of the snap element 24, with no teeth formed on the portion between the two oppositely facing portions. This has advantages with regard to the manufacture of the injection pen 10. Alternatively, the teeth 110 may be formed along the entire circumference of the snap element 24.

[0060] The snap element 24 forms an axial portion with a reduced cross section that forms a coupling surface 112 for the connector 26. The connector 26 shown in the figures is formed as a one-piece part. However, the connector 26 may also be formed from several parts, for example two parts, that are connected to each other, for example by a form-fit connection. The connector 26 has an open cross section (see FIG. 7D) so that it can clip onto the reduced cross section of the snap element 24. The connector 26 is axially fixedly connected to the snap element 24 in both directions, since it has an axial length L1 that corresponds to the axial length L2 of the axial portion with the reduced cross section. However, the connector 26 is rotatable relative to the snap element 24. When the dose setting knob 22 is pressed in the proximal direction 1 to initiate the delivery of a dose, the teeth 108 of the dose setting knob 22 engage with a set of teeth 114 formed on the outer circumferential surface of the connector 26 instead of the teeth 110 of the snap element 24, so that the snap element 24 can rotate relative to the dose setting knob 22 during the delivery of the dose. The engagement between teeth 108 of the dose setting knob 22 and teeth 114 of the connector 26 ensures that the dose setting knob 22 does not rotate relative to the housing 32 during delivery of a dose because the connector 26 is rotationally fixed to the housing 32 via the dose selector 28.

[0061] The snap element 24 further comprises an engagement feature 116 in the form of an axially extending radial protrusion. The engagement feature 116 is an axially extending rib. The engagement feature 116 can have a symmetrical or asymmetrical cross-section in a radial plane perpendicular to the longitudinal axis of the injection pen 10. The engagement feature 116 is configured to engage with dose stops 118a, 118b, 118c, and 118d (see FIG. 8B) formed on the inner circumferential surface of the dose selector 28 to set the desired dose. The engagement feature 116 is thus used as a dose defining element, and together with the dose stops 118a, 118b, 118c, 118d, the engagement feature 116 forms the dose defining feature 115 of the injection pen 10. The dose defining element 116 is arranged on an axially extending arm partially surrounded by an elastically deformable portion 120, i.e. a notch 121. The elastically deformable portion 120 bends inwards when the dose defining element 116 passes through one of the dose stops 118a, 118b, 118c and 118d. To reduce the force required to rotate the dose setting knob 22 and the snap element 24 relative to the dose selector 28 to increase or decrease the dose to be set, the dose stopper 118 has chamfered side faces 122a-122d and 123a-122d. According to the embodiment shown in Fig. 8B, the dose stops 118a-118d have a symmetrical cross section in a radial plane perpendicular to the longitudinal axis of the injection pen 10. In other words, the chamfered side faces 122 and 123 have equal pitches with respect to their volume. According to another embodiment shown in Fig. 9, the chamfered side surfaces 122a'-122d', which contact the projection 116 and deform the elastically deformable portion 120 when setting the dose to a higher dose, have a smaller pitch than the chamfered side surfaces 123a'-123d', which contact the projection 116 when setting the dose to a lower dose. The side surfaces 123a-123d define rotational positions corresponding to the settable doses. A spring 40 is configured to rotate the snap element 24 relative to the dose selector 28 such that the dose defining element 116 abuts against one of the side surfaces 123a-123d.

[0062] The snap element 24 further comprises a hard stopper 124 in the form of an axially extending rib that abuts a hard stopper 126 formed on the dose selector 28 when the injection pen 10 is delivered to a customer. In contrast to known pens, the hard stopper 126 does not correspond to a zero-dose stopper, but instead to a preset dose stopper. This feature will be discussed further below. The hard stopper 124 is axially spaced from the dose defining element 116 but is axially aligned with it. The hard stopper 124 is configured to abut an end of the dose setting hard stopper 128.

[0063] The snap element 24 further comprises axial and rotational fixing means in the form of a radially extending opening 130 and an axially extending slot 132 for fixing the snap element 24 to the driver 36 for axial movement and rotation. As seen in FIG. 13A, the driver 36 has an axially extending rib 134 configured to engage with the slot 132 of the snap element 24. Furthermore, the driver 36 has a protrusion 136 having a chamfered surface 136a that engages with the opening 130 of the snap element 24. The opening 130 and the protrusion 136 form the axial fixing means, while the slot 132 and the rib 134 form the rotational fixing means. The axial and rotational fixing means allow the snap element 24 and the driver 36 to be connected to each other in one defined relative rotational position. To enhance the rotational fixation between the snap element 24 and the driver 36, the inner circumferential surface of the snap element 24 (see FIG. 6C) is formed with an axially extending rib 138 which engages with an axially extending groove 140 (see FIG. 13D) in the outer circumferential surface of the driver 36.

[0064] 8A-8E show the dose selector 28. The dose selector 28 comprises an axial fixing means 142 in the form of a circumferentially extending protrusion on the inner circumferential surface of a distal portion of the dose selector 28. The dose selector 28 is axially fixed to the dose setting knob 22 by inserting the distal portion having the axial fixing means 142 into a circumferentially extending inlet 144 (see FIG. 5B). At the inlet 144 the dose setting knob 22 forms an axial fixing means 146 in the form of a circumferentially extending protrusion on its outer circumferential surface which engages with the axial fixing means 142 of the dose selector 28 to form an axial connection allowing relative rotational movement between the dose selector 28 and the dose setting knob 22.

[0065] As best seen in FIG. 8E, a rotational fixing means 148 in the form of an axially extending groove is formed on the inner circumferential surface of the dose selector 28. The rotational fixing means 148 engages with a rotational fixing means 150 in the form of an axially extending rib formed on the outer circumferential surface of the connector 26 (see FIG. 7B). The rotational fixing means 148, 150 allow axial movement between the dose selector 28 and the connector 26. The dose selector 28 further comprises a rotational fixing means 152 in the form of an axially extending rib formed on the outer circumferential surface of the dose selector 26. The rotational fixing means 152 engages with a rotational fixing means 154 in the form of an axially extending groove formed on the inner circumferential surface of the housing 32 (see FIG. 11C). The rotational fixing means 152, 154 are configured to define only one possible rotational alignment that allows insertion of the dose selector 28 into the housing 32. The rotational fixing means 150, 152 allow axial movement between the dose selector 28 and the housing 32.

[0066] To define the deliverable doses, the dose selector 28 (see FIG. 8B) forms a circumferentially extending rib 156 with notches 158a, 158b, 158c, and 158d, which are assigned to the respective dose stops 118a, 118b, 118c, and 118d. The rib 156 with the notches 158a, 158b, 158c, and 158d ensures that an injection is only possible when the dose defining element 116 of the snap element 24 is in an angular position associated with one of the notches 158a, 158b, 158c, and 158d, i.e. associated with one of the settable doses. If the dose defining element 116 is not in an angular position associated with one of the notches 158a-158d, axial movement of the dose defining element 116, and thus the snap element 24, relative to the dose selector 28 is prevented by the circumferentially extending rib 156. As can be seen in Fig. 8B, the preset dose hard stopper 126 does not have a notch assigned to it. Thus, the start of an injection is prevented when the injection pen 10 is set to a preset dose.

[0067] According to another embodiment, the circumferentially extending rib 156 may be arranged to interact with the hard stopper 124 instead of the dose defining element 116. Thus, injection is only possible when the hard stopper 124 of the snap element 24 is in an angular position associated with one of the notches 158a, 158b, 158c and 158d, i.e. associated with one of the settable doses.

[0068] 10A and 10B show the knob key 30. The knob key 30 is configured to be attached to the outer periphery of the dose selector 28 and to prevent the dose setting knob 24 from unintentionally moving in the proximal direction 1 relative to the housing 32 if the as-delivered injection pen 10 is dropped from its proximal end. The clip element 30 has a width W1 that corresponds to the width W2 (see FIG. 29A ) between the proximal edge 160 of the dose setting knob 22 and the distal edge 162 of the housing 32. The knob key 30 is C-shaped and has a retaining protrusion 164 that interacts with a rotational fixing means 152 on the outer periphery of the dose selector 28 to attach the knob key 30 to the dose selector 28. The knob key 30 can be removed from the dose selector 28 by slightly bending the C-shaped knob key 30. In the as-delivered state, the knob cover 16 extends around the knob key 30 and holds it in place. The knob key 30 can only be removed from the dose selector 28 after the knob cover 16 has been removed.

[0069] The housing 32 is shown in Figures 11A-11C. The housing 32 forms an observation window 166 for displaying the status of the injection pen 10, in particular the set dose indicated by the dose sleeve 34, through which the window 166 is displayed. The dose sleeve 34 rotates relative to the housing during dose setting and dose delivery, which changes the content of the display in the window 166. At various circumferential positions along the outer circumferential surface of the dose sleeve 34, labels 168a-168d (see Figures 12C and 12D) relating to the various settable doses are arranged. Furthermore, a preset dose label 168e (see Figure 12B) is arranged on the dose sleeve 34, which corresponds to a preset dose, i.e. the amount of medicine that would be injected if an injection could be started from the preset dose. The preset dose label 168e, which can be seen from a comparison of Figures 12A and 12B, is different from the zero dose label 168f, i.e. a label indicating that no medicine will be injected if an injection is started in that state. This zero dose label 168f is indicated through the window 166 when the injection is completed. Labels 168a, 168b, 168c, and 168d correspond to the settable doses defined by dose stops 118a, 118b, 118c, and 118d.

[0070] The dose sleeve 34 is rigidly coupled for rotation and axial movement to the driver 36 (see Figures 13A-13D). To rotationally couple the dose sleeve 34 to the driver 36, corresponding non-circular outer and inner peripheral surfaces 169a, 169b are formed on the driver 36 and the dose sleeve 34, respectively. Furthermore, the dose sleeve 34 forms a fixing portion 171 that is sandwiched between the proximal end of the snap element 24 and a face surface 173 (see Figure 13A) of the driver 36 to axially fix the dose sleeve 34 to the driver 36 and the snap element 24. The driver 36 forms an external thread 170 that engages with an internal thread 172 (see Figures 16A and 16B) of the piston guide 42. The threaded connections 170, 172 allow the driver 36 to rotate when the driver 36 moves axially relative to the piston guide 42 and to move axially relative to the piston guide 42 when the driver 36 rotates relative to the piston guide 42. The driver 36 further defines an end stop 174 which abuts an end stop 176 of the piston guide 42 at the end of dose delivery. The surfaces defining the end stops 174, 176 are arranged parallel to the central axis of the injection pen and face radially. The driver 36 further defines attachment means 177 in the form of a radially extending hook for attaching one end of the spring 40 to the driver 36. The other end of the spring 40 is attached to attachment means 179 (see FIG. 16C) on the outer circumferential surface of the piston rod guide 42.

[0071] According to another variant, the dose sleeve and the driver can be formed as separate parts that are axially movable relative to each other but rotationally fixed relative to each other, and both the dose sleeve and the driver can have a thread that screws into the housing. The thread of the dose sleeve and the thread of the driver may have different pitches.

[0072] The piston guide 42 is fixed axially and radially to the housing 32 and can therefore be considered as part of the housing. To axially fix the piston guide 42 to the housing 32, an axial fixing means 178 in the form of a circumferentially extending groove is formed in the piston guide 42 and engages with an axial fixing means 180 (see FIG. 11A) in the form of a circumferentially extending rib formed on the inner peripheral surface of the housing 32. To rotationally fix the piston guide 42 to the housing 32, a rotation fixing means 182 in the form of an axially extending groove is formed in the outer peripheral surface 262 of the piston guide 42 and engages with a rotation fixing means 184 (see FIG. 11A) in the form of an axially extending rib formed on the inner peripheral surface of the housing 32. The axial fixing means 178 and 180 as well as the rotation fixing means 182 and 184 make it possible to mount the piston rod guide 42 to the housing 32 in exactly one relative rotational position.

[0073] The piston guide 42 has a non-circular axial opening 186 (see FIG. 15C) that corresponds to the non-circular cross section 188 (see FIG. 17B) of the piston rod 44. Thus, the piston rod 44 is axially movable relative to the piston rod guide 42, but cannot rotate relative to the piston rod guide 42. The piston rod 44 forms an external thread 190 that engages with an internal thread 192 (see FIG. 14D) of the nut 38. The external thread 190 and the internal thread 192 form a threaded connection 189 between the piston rod 44 as the first threaded element and the nut 38 as the second threaded element. The piston rod 44 and the nut 38 can move relative to each other in a forced guided combined axial and rotational motion. At the proximal end portion of the nut 38, a distally extending annular push surface 194 is formed on the nut 38. This push surface 194 abuts against a front face 196 of the driver 36 during dose delivery. During dose delivery, the driver 36 moves relative to the piston rod guide 42 in a combination of axial and rotational movement, while the nut 38 is rotationally fixed to the housing 32. To reduce friction during dose delivery, ball bearings and / or sliding disks made of low-friction material can be arranged between the pushing surface 194 and the front face 196 of the driver 36. In either case, during dose delivery, the driver 36 pushes the piston rod 44 in the proximal direction 1 via the nut 38.

[0074] At its proximal end, the piston rod 44 forms a coupling means 200 in the form of an undercut which engages with a coupling means 198 in the form of a radially inwardly extending rib on the inner circumferential surface of the piston disc 46 (see Figures 18A-18C).

[0075] 15A-22B show parts of a drug mixing or reconstitution unit 56 configured to mix various components, typically a lyophilized drug and a liquid solvent, to form an injectable liquid drug. In FIGS. 19A-19C, a dual chamber cartridge 48 is shown. The dual chamber cartridge 48 is made of a transparent material, such as glass. As can be seen in FIG. 19C, the cartridge 48 forms a first chamber 202 and a second chamber 204. In the as-delivered state shown in FIG. 19C, the first chamber 202, which is disposed proximal to the second chamber 204, comprises a bypass 206. The first chamber 202 and the second chamber 204 are separated by a first sealing element 208, for example made of a rubber material, which is axially slidably disposed inside the dual chamber cartridge 48. In other words, the first sealing element 208 forms the distal end of the first chamber 202 and the proximal end of the second chamber 204. A second sealing element 210, made for example of a rubber material, forms the distal end of the second chamber 204. The second sealing element 210 may also be referred to as a plunger. The piston disc 46 abuts against a distal end face of the second sealing element 210 upon mixing of the two components.

[0076] As delivered, the lyophilized drug is in the first chamber 202 and the solvent is in the second chamber 204 .

[0077] The dual chamber cartridge 48 is accommodated in a cartridge key 52 (see Figs. 21A-22b). The cartridge key 52 is fixed in the cartridge receptacle 50 with respect to axial movement and rotation. To achieve this, the cartridge key 52 forms an axial fixing means 212 in the form of a circumferentially extending groove that engages with an axial fixing means 214 in the form of a circumferentially extending rib on the inner peripheral surface of the cartridge receptacle 50 (see Fig. 20A). Furthermore, the cartridge key 52 forms a rotation fixing means 216 in the form of a radially extending rib that engages with a rotation fixing means 218 in the form of a radially extending groove on the inner peripheral surface of the cartridge receptacle 50. When the cartridge key 52 is mounted in the cartridge receptacle 50, an annular end surface 266 (Fig. 22B) lightly abuts a corresponding annular end surface 268 (Fig. 20A) of the cartridge receptacle 50. Both annular end surfaces 266 and 268 can be arranged perpendicular to the longitudinal axis of the pen 10. Additionally, when the cartridge key 52 is attached to the cartridge receptacle 50, a window 220 formed in the cartridge key 52 aligns with a window 222 in the cartridge receptacle 50 so that the patient can view the medication inside the transparent dual chamber cartridge 48 during reconstitution. The proximal end of the cartridge key 52, which also defines the proximal end of the injection pen 10, is formed with threads 224 for mounting a needle (not shown). The threads 224 surround an opening 252 in the proximal end of the cartridge holder 52. The opening 252 is configured to receive a needle that is in fluid communication with the interior of the cartridge 48 inserted into the cartridge holder 52.

[0078] The cartridge key 52 forms an inner surface 254 (FIG. 22B) that defines a cylindrical receptacle that receives the cartridge 48 and prevents tilting of the cartridge 48 relative to the longitudinal axis. Tilting of the cartridge 48 is prevented by surface contact between a cylindrical outer surface 256 of the cartridge and an inner surface 254 of the holding portion 249 of the cartridge holder 52. In addition, the cartridge holder 52 forms a notch 221 for receiving the bypass 206 of the dual-chamber cartridge 48. The bypass 206 engages by form-fitting in the notch 221 such that the dual-chamber cartridge 48 is fixed against axial movement and rotation to the cartridge key 52. ​​Opposite the notch 221 is formed an axially extending slot 223. The slot 223 allows the cartridge key 52 to be reversibly widened for axial insertion of the dual-chamber cartridge 48 with the bypass 206.

[0079] To mix the separate components in the dual-chamber cartridge 48 and prime the injection pen 10, the cartridge receptacle 50 is screwed into the piston rod guide 42 until the distal end face 226 of the cartridge receptacle 50 abuts the proximal face 228 (see FIG. 15B ) of the piston guide 42. To do this, the cartridge receptacle 50 forms an outer surface 246 that can be grasped with one hand to screw the cartridge receptacle 50 into the piston rod guide 42. As the cartridge receptacle 50 is screwed into the piston rod guide 42, the proximal portion of the piston rod guide 42 enters an annular space 258 ( FIG. 23B ) between an outer peripheral surface 264 of the cartridge holder 52 and an inner peripheral surface 260 of the cartridge receptacle 50, which defines an interior space 248 of the cartridge receptacle 260. To screw the cartridge receptacle 50 into the piston rod guide 42, a first thread 230 is formed on the inner peripheral surface 260 of the cartridge receptacle 50 and engages with a second thread 232 formed on the outer peripheral surface 262 of the piston rod guide 42. As seen in FIG. 15A, the piston rod guide 42 forms a snap element 234. The snap element 234 allows the screwing of the cartridge receptacle 50 into the piston rod guide 42 in the distal direction, i.e., a forced guided combined axial and rotational movement, but prevents the rotation of the cartridge receptacle 50 into the piston rod guide 42 in the proximal direction 1 when the snap element 234 engages with one of the openings 236, 238, and 240. The first opening 236 (see FIG. 20B) is configured to define a starting position of the cartridge receptacle 50 and ensures that the cartridge receptacle 50 cannot be dislodged from the piston rod guide 42. This starting position or as-delivered state is shown in FIGS. 25A and 25B.

[0080] The second opening 238 defines the reconstituted state of the cartridge container 50. In this state, the second chamber 202 still contains air, so the injection pen 10 can be moved back and forth to ensure that the medicament is evenly mixed. The second opening 238 may be omitted. Thus, the present disclosure also relates to an embodiment of the injection pen 10 that includes the first opening 236 and the third opening 240, but does not include the second opening 238. The third opening 240 defines the knob cover unlocked state of the cartridge container 50, in which most of the air has been expelled from the second chamber 202, which now contains the medicament that is reconstituted and ready to use.

[0081] Various states of the injection pen 10 during use thereof will now be described with reference to Figures 23A-33B.

[0082] 23A-25B show the injection pen 10 in the as-delivered state. As can be seen from FIG. 23A, the knob cover 16 covers the distal end portion of the injection pen 10 up to the junction of the housing 32 and the piston guide 42. The dose setting knob 22 is therefore completely covered by the knob cover 16 and in this state the user cannot prematurely set the dose. Turning to FIG. 23B, it can be seen that in the as-delivered state the drug reconstitution unit 56 forms two separate chambers 202, 204 divided by the first sealing element 208. This means that each of the two components of the drug is contained in one of the two chambers 202, 204 respectively and has not yet been mixed together. As can be seen from FIG. 24, where the knob cover 16 has been omitted to show what is present below the knob cover 16, the dose setting sleeve 34 indicates that the injection pen 10 is in a preset state different from the zero dose state. Thus, the dose setting knob 22 is also in a preset position different from the zero dose position. As seen in Figures 25A and 25B, the snap element 234 of the piston rod guide 42 snaps into a first opening 236 of the cartridge receptacle 50. In Figure 24, the cartridge receptacle 50 is depicted as semi-transparent to show the first thread 230 formed on the inner circumferential surface of the cartridge receptacle 50. Secondly, the piston rod guide 42 is also depicted as semi-transparent to show the position of the piston rod 44 in the preset state.

[0083] To start the preparation of the drug, as can be seen from a comparison of Figs. 25A and 26A, the user rotates the cartridge container 50, which includes the cartridge key 52 and the dual-chamber cartridge 48, and moves the cartridge container 50 distally relative to the piston rod guide 42. This moves the piston rod guide 42 into the annular space 258 (Fig. 23B) between the cartridge container 50 and the cartridge holder 52. The piston disc 46 is snap-fitted onto the piston rod 44, which is rotationally fixed by the piston rod guide 42 and axially fixed by the nut 38. The piston disc 46 thus prevents the movement of the second seal element 210 disposed within the dual-chamber cartridge 48, and thus the second seal element 210 slides along the inner circumferential surface of the dual-chamber cartridge 48 as the cartridge container 50 is further screwed onto the piston rod guide 42. The solvent contained in the second chamber 204 presses against the first sealing element 208, which also slides along the inner circumferential surface of the dual chamber cartridge 48. This would cause an overpressure in the cartridge, but the air can escape through a double-ended needle that the user attaches to the threads 224. When the first sealing element 208 reaches the bypass 206 (see FIG. 23B), the first chamber 202 and the second chamber 204 are connected by the bypass 206, thus allowing the lyophilized drug contained in the first chamber 202 and the solvent contained in the second chamber 204 to mix.

[0084] In the reconstituted state shown in Figs. 26A-27C, the mixed drug is contained in the first chamber 202 between the first seal element 208 and the proximal end 14 of the dual chamber cartridge 48. As can be seen in Fig. 26B, the proximal end face of the second seal element 210 abuts against the distal end face of the first seal element 208, and therefore, in the reconstituted state, the second chamber 204 is no longer present. As can be seen in Fig. 27C, the snap element 234 of the piston rod guide 42 snaps into the second opening 238 of the cartridge container 50. In this state, the front chamber 202 still contains a significant amount of air, which helps to create turbulence when moving the pen, making it easier to mix the lyophilized drug. As mentioned above, the second opening 238 may be omitted. In that case, mixing occurs with a small amount of remaining air.

[0085] After the reconstitution of the drug is completed, the user further rotates the cartridge container 50, moving it further axially in the distal direction relative to the piston rod guide 42. This causes the displacement portion 242 located at the distal end of the cartridge container 50 to engage with and spread radially outwardly with the wings 58 of the knob cover 16 (see FIG. 28B). The radially outward spreading of the wings 58 disengages the form-fitting engagement means 60 of the knob cover 16 from the coupling surface 228, allowing the knob cover 16 to be moved axially relative to the housing 32. The knob cover 16 can now be pulled distally away from the housing 32, resulting in the state shown in FIGS. 29A and 29B. When the cartridge container 50 is fully screwed into the piston rod guide 42, the radial end stop 244 formed on the outer circumferential surface 262 of the piston rod guide 42 abuts against the radial end stop (not shown) on the inner circumferential surface of the cartridge container 50. Additionally, the snap element 234 of the piston rod guide 42 snaps into the third opening 240. As a result, the cartridge receptacle 50 is rotationally locked to the piston rod guide 42 and housing 32 of the device. Thus, movement of the cartridge receptacle 50 and cartridge 48 relative to the housing 32 and piston rod guide 42 is prevented.

[0086] 29A and 29B, at this stage the knob key 30 is still clipped onto the outer circumferential surface of the dose selector 28 between the proximal edge 160 of the dose setting knob 22 and the distal edge 162 of the housing 32. Only after the knob cover 16 is removed can the knob key 30 be removed from the dose selector 28 by bending it slightly.

[0087] Thereafter, as can be seen by comparing Figures 29A and 30A, the user rotates the dose setting knob 22 to set a desired dose from a number of possible settable doses. In this example, the dose setting knob 22 is rotated 180° to set the desired dose. When the dose setting knob 22 is rotated, it performs a forced guided combined axial and rotational motion, i.e. a distal screwing motion.

[0088] Rotation of the dose setting knob 22 causes rotation of the injection button 18, which is axially and rotationally connected to the dose setting knob 22 via the snap ring 20, the snap element 24, which is rotationally and axially connected to the dose setting knob 22 via the teeth 108 that mesh with the teeth 110, the driver 36, which is rotationally and axially coupled to the snap element 24, and the dose setting sleeve 34, which is rotationally and axially coupled to the driver 36. Rotation of the driver 36 axially moves the driver 36 distally due to the engagement of the external threads 170 of the driver 36 with the internal threads 172 of the piston rod guide 42. The axial movement of the driver 36 moves the snap element 24 distally and pushes the injection button 18 and the dose setting knob 22 distally via the coupling means 102 of the snap element 24 that interact with the assembly means 98 of the injection button 18. The dose setting knob 22 thereby performs a combined axial and rotational movement that is forcibly guided when setting a dose.

[0089] Furthermore, rotation of the dose setting knob 22 causes rotation of the injection button 18, which is rotationally coupled to the nut 38. Because the piston rod 44 is rotationally fixedly coupled to the piston rod guide 42 by virtue of the corresponding non-circular cross sections 186, 188, rotation of the dose setting knob 22, and thus the nut 38, causes the nut 38 to move in a distal direction.

[0090] The amount of axial movement of the nut 38 relative to the piston rod 44 and the driver 36 relative to the piston guide 42 depends on the pitch of their respective threads. The external threads 170 of the driver 36 have a larger pitch than the external threads 190 of the piston rod 44, and therefore the driver 36 moves distally more than the nut 38. For example, the external threads 170 of the driver 36 may have a pitch of 10.71 mm and the external threads 190 of the piston rod 44 may have a pitch of 10.21 mm.

[0091] Once the desired dose is set, the helical torsion spring 40 applies a torque to the snap element 24 via the driver 36 causing the dose defining element 116 to abut against the respective dose stop 118a-118d, i.e. against its side surface 122b. By virtue of the spring 40, the injection pen 10 is configured to automatically rotationally align the snap element 24 and the dose selector 28 to various predefined rotational positions that define the desired doses.

[0092] When the user subsequently presses the injection button 18 at the distal end 12 of the injection pen 10, the dose setting knob 22 moves in the proximal direction 1 relative to the snap element 24. This causes the coupling means 100 to bend as it passes the circumferential ledge 102, creating a distal reaction force that the user must overcome to initiate the injection process. The proximal direction 1 movement of the dose setting knob 22 relative to the snap element 24 also causes the teeth 108 of the dose setting knob 22 to move out of engagement with the teeth 110 of the snap element 24 and instead engage the teeth 108 of the dose setting knob 22 with the teeth 114 of the connector 26. The connector 26 is rotationally coupled to the housing 32 via the dose selector 28, so that the dose setting knob 22 is rotationally fixed to the housing 32. Thus, the dose setting knob 22, the injection button 18, the dose selector 28, and the nut 38 do not rotate relative to the housing 32 during dose delivery.

[0093] As the user presses the injection button 18 further, the injection button 18 and the dose selector 28 move in the proximal direction 1 relative to the snap element 24. This causes the dose defining element 116 of the snap element 24 to pass through the circumferentially extending rib 156 on the dose selector 28 through the respective cut-outs 158a-158d corresponding to the set dose. At the same time, the hard stop 126 of the dose selector 28 moves axially relative to the hard stop 124 on the snap element 24, allowing the dose selector 28 and the snap element 24 to rotate relative to one another past the preset dose position towards the zero dose position.

[0094] When the injection button 18 is pressed during dose delivery, it pushes the driver 36 in the proximal direction 1 via the snap element 24. The spring 40 supports the axial movement of the driver 36 by applying a torque to the driver 36, which results in an axial movement of the driver 36 in the proximal direction 1 due to the male thread 170 of the driver 36. The driver pushes the nut 38 in the proximal direction 1, which causes the piston rod 44 to move in the proximal direction 1. The movement of the piston rod 44 and the piston disc 46 in the proximal direction 1 results in the injection of the drug into the patient. Since the injection pen 10 is made to inject a relatively large amount of drug, the pen 10 does not have a so-called gearing. In other words, the parts that are configured to rotate relative to the housing during dose delivery are connected to the housing 32. This means that the distance of advancement of the piston disc 46 is essentially equal to the distance the injection button 18 is pushed in the proximal direction 1 relative to the housing 32.

[0095] As the driver rotates relative to the housing due to its external threads 170, the dose setting sleeve 34 rotates during delivery of the dose. At the end of dose delivery (see Figures 33A and 33B), the dose setting sleeve 34 is in a rotated position where the dose zero label is visible through the window 166 in the housing 32. The end of the dose stopper 174 (see Figure 13B) of the driver 36 and the end of the dose stopper 176 (see Figure 16C) of the piston rod guide 42 define the end of the movement of the injection button 18 in the proximal direction 1 during dose delivery.

[0096] At the end of dose delivery, the coupling means 100 on the injection button 18 passes the coupling means 102 of the snap element 24 at the start of the injection, permanently rotationally coupling the dose setting knob 22 and the injection button 18 to the housing 32. Thus, the injection pen 10 is rendered inoperable as the user cannot rotate the dose setting knob 22 to set a new dose.

[0097] The injection pen 10 allows for adjusting the axial position of the piston rod 44 relative to the housing 32 in a pre-assembled state of the dose delivery mechanism 54. In the pre-assembled state, the injection button 18 forming the adjustment element 18 of the dose delivery mechanism 54 engages with its distal assembly means 98a with the coupling means 102 of the snap element 24. This allows the injection button 18 to be placed in a more distal pre-assembled position compared to its assembled position in the assembled state of the dose delivery mechanism 54, in which the adjustment element 18 engages with the coupling means 102 with its proximal assembly means 98b.

[0098] In the pre-assembled position, the adjustment element 18 protrudes from the dose setting element 22 and can rotate freely relative to the dose setting element 22. Rotation of the adjustment element 18 then rotates the nut 38 relative to the piston rod 44, thereby causing an axial movement of the piston rod 44 due to the threaded connection 189 between the piston rod 44 and the nut 38.

[0099] The adjustment of the piston rod 44 in the pre-assembled state will be described in further detail below in relation to a second injector pen 330 according to the present disclosure, which is a variant of the injector pen 10 shown in the previous figures.

[0100] Figures 34 and 35 show the second injector pen 300 in a preassembled state, Figure 36 shows an exploded view of the second injector pen, and Figure 37 shows a longitudinal section of the second injector pen 300 in a preassembled state. Unless differences are disclosed in the specification or drawings, the second injector pen 300 is constructed as disclosed for the injector pen 10 of the preceding figures, and vice versa.

[0101] The second injector pen 300 includes a dose delivery mechanism 354. Unless otherwise disclosed in the specification or drawings, the dose delivery mechanism 354 of the second injector pen 300 is configured as disclosed for the dose delivery mechanism 54 of the injector pen 10, and vice versa.

[0102] The dose delivery mechanism 354 comprises a housing 332 having an upper housing part 333 and a piston rod guide 342 forming a lower housing part. The upper housing part 333 and the piston rod guide 342 are rigidly connected to each other via a form-fit connection. In particular, the upper housing part 333 and the piston rod guide 342 are axially and rotationally fixed to each other. The lower housing part formed by the piston rod guide 342 is configured to be connected to a medicine container holder 305 which receives a medicine container 348. The medicine container holder 305 comprises a connector 307 located at a distal end of the medicine container holder 305. The connector 307 is configured to be connected to a corresponding connector 343 of the piston rod guide 342, which corresponding connector 343 is accessible at a proximal side of the piston rod guide 342. Connectors 307 , 343 provide a non-releasable form-fit connection between medicine container holder 305 and housing 332 after attachment of medicine container holder 305 to housing 332 .

[0103] The drug container 348 has a single drug chamber sealed at its distal end by a single plunger 210 (see FIG. 35). The drug chamber contains a fluid drug. At its proximal needle end 349, the drug container 348 includes a septum configured to be punched out upon attachment of a double ended cannula to a needle connector 306 located at the proximal end of the drug container holder 305. A cap 301 is releasably attachable to the drug container holder 305 during storage of the injection pen 300.

[0104] The dose delivery mechanism 354 comprises the injection button constituting the adjustment member 318, the snap element 24, the dose metering element 334 and a driver 336. In the pre-assembled and assembled state of the injection pen 300, the snap element 24 and the dose metering element 334 are rigidly connected to each other and form the dose metering member 323 of the dose delivery mechanism 354. The dose metering element 334 is coupled to the housing 332 of the dose delivery mechanism 354 via a threaded connection 335. The threaded connection 335 comprises an external thread on the outer surface of the dose metering member 323 and an internal thread (not visible in FIG. 36 ) on the inner surface of the housing 332. In other embodiments, the dose metering member 323 may be constructed as a single component.

[0105] The dose metering member 323 constitutes a dose indicating member of the dose delivery mechanism 354. The dose metering element 334 is thereby provided with markings which are visible through a window in the upper housing part 333 of the housing 332 when the dose metering member 323 is rotated relative to the housing 332 during setting of a dose.

[0106] The driver 336 is connected to the housing 332 via a further threaded connection 337 acting between the driver 336 and the piston rod guide 42, as described for the driver 336 and the piston rod guide 342 of the injection pen 10. Furthermore, the driver 336 is rotationally fixed and axially movable relative to the dose metering member 323 via a splined connection. Thereby, the driver 336 is received in a dose metering element 334 of the dose metering member 323. The splined connection comprises a first splined element on an outer periphery of the driver 336, which engages with a corresponding second splined element on an inner periphery of the dose metering element 334. The simultaneous rotation of the driver 336 and the dose metering member 323 requires an axial movement of the driver 336 by means of the further threaded connection 337 to the housing 332 and a simultaneous axial movement of the dose metering member 323 by means of the threaded connection 335 to the housing 332.

[0107] The pitch of the threaded connection 335 between the dose metering element 334 and the housing 332 is offset from the pitch of a further threaded connection 337 between the driver 336 and the housing 332. The ratio of these pitches determines the mechanical advantage of the dose delivery mechanism 354 during delivery of a dose, such that forced proximal movement of the dose metering member 334 a first axial distance results in proximal movement of the driver 336 a second axial distance different from the first axial distance.

[0108] FIG. 38 shows a detailed view of the distal part of the second injection pen 300 in a pre-assembled state. The adjustment element 318 differs from the adjustment element 18 of the injection pen 10 in that it does not comprise a coupling means 100 for axially locking the adjustment element 18 to the snap element 24 when delivering a dose. The second injection pen 300 therefore allows for repeatedly setting and injecting user-definable doses. Apart from this modification, the adjustment element 318 is configured similarly as disclosed for the adjustment element 18 and vice versa. In particular, the adjustment element 18 of the injection pen 10 is configured to adjust the position of the piston rod 46 in the pre-assembled state in the same way as disclosed below for the adjustment element 318 of the second injection pen 300. Furthermore, the adjustment element 318 forms an actuating member of the second injection pen 300. The actuating member is configured to be operated by a user to deliver a set dose. Exemplarily, the actuating member is configured to be pushed proximally by a user to deliver a set dose.

[0109] In the pre-assembled state shown in Figures 37 and 38, the proximal assembly means 98b of the adjustment element 318 engage with the coupling means 102 of the snap element 24, allowing the adjustment element 318 to be placed in a pre-assembled position relative to the housing 332. The pre-assembled position is the most distal axial position of the adjustment element 318 reached when the assembly means 98b engages with the coupling means 102 of the snap element 24 upon distal movement of the adjustment element 318. A biasing element 250 in the form of a spring acts between the snap element 24 and the adjustment element 318, biasing the adjustment element 318 distally towards the pre-assembled position. Since the injection pen 10 does not comprise a biasing element 250, the adjustment element 18 of the injection pen 10 is not held in a pre-assembled position. In the injection pen 10, the adjustment element 18 is manually placed in the pre-assembled position by the device assembler.

[0110] The assembly means 98b form the latch part of the latch mechanism 99 and the coupling means 102 of the snap element 24 form the latch counterpart of the latch mechanism 99. Furthermore, the dose metering member 323 with the snap element 24 forms the counter member of the latch mechanism 99. The latch mechanism 99 prevents the adjustment element 318 from being removed from the housing 332 in the pre-assembled state.

[0111] In the pre-assembled position, the adjustment element 318 protrudes distally from the dose setting element formed by the dose knob 22. Thus, the rotational locking means 90 of the adjustment element 318 does not engage with the rotational locking means 94 of the snap ring 20, and thus the adjustment element 318 is rotationally moveable relative to the housing 332 and the dose setting element 22.

[0112] In the pre-assembled position, the outer rim 19 of the adjustment element 318 is accessible to the assembler of the injection pen 300. When the adjustment element 318 is rotated relative to the housing 332 and the dose setting element 22, the adjustment element 318 rotates the nut 38. This prevents the nut 38 from moving axially relative to the housing 332, since the immobile driver 336 presses against the pressing surface 194 at the proximal end of the nut 38. The threaded connection 189 between the piston rod 44, which forms the first threaded element, and the rotating nut 38, which forms the second threaded element, thus allows the piston rod 44 to move axially relative to the housing 332. In this way, the second injection pen 300 allows the axial position of the piston rod 44 to be adjusted by rotating the adjustment element 318 relative to the housing 332 and the dose setting element 22. The same is true for the injection pen 10, in which the injection button 18 also forms the adjustment element.

[0113] Each of the dose delivery mechanisms 54, 354 of the injection pen 10, 300 comprises a rotation lock 89 formed by a rotation fixing means 90 of the respective adjusting element 18, 318 and by a toothed portion 93 of the respective snap ring 20. The snap ring 20 thereby forms a connector between the respective adjusting element 18, 318 and the respective dose setting element 22, the adjusting element 18, 318 being rotationally and / or axially fixed to the dose setting element 22 in the assembled state by the connector 20. Furthermore, the dose setting element 22 forms a counter element to which the adjusting element 18, 318 is attached in the assembled state of the respective dose delivery mechanism 54, 354.

[0114] Furthermore, the axial fixing means 82 of the adjusting element 18, 318 and the rib 84 of the snap ring 20 each form an axial lock 81 that allows axial movement between the adjusting element 18, 318 and the dose setting element 22 in a pre-assembled state of the dose delivery mechanism 54, 354 and prevents axial movement between the adjusting element 18, 318 and the dose setting element 22 in the assembled state.

[0115] The axial fixing means 82 of the adjusting element 18, 318 and the rib 84 of the snap ring 20 also form a latching mechanism acting between the adjusting element 18, 318 and the counter element formed by the dose setting element 22. In the assembled state of the dose delivery mechanism 54, 354, the latching mechanism prevents the adjusting element 18, 318 from moving from a second position relative to the counter element to a first position relative to the counter element, whereby the second position is a proximal position in which the adjusting element 18, 318 is rotationally and axially fixed to the counter element and the first position is a distal position which the adjusting element 18, 318 occupies in the pre-assembled state, in which the adjusting element 18, 318 is rotatable relative to the counter element.

[0116] Figure 39 shows a detailed longitudinal section of the distal end of the second injection pen 300 in the assembled state during dose setting, and Figure 40 shows a further detailed longitudinal section of the distal end of the second injection pen 300 in the assembled state during dose setting. The longitudinal section cuts shown in Figures 39 and 40 are oriented perpendicular to each other.

[0117] The injection pen 300 is transferred from the pre-assembled state to the assembled state by moving the adjustment element 318 proximally from the pre-assembled position to the assembled position relative to the dose setting element 22 and the housing 332. The adjustment element 318 is thereby rotationally and axially locked to the dose setting element 22 via the connector 20, the rotation lock 89 and the axial lock 81. In the assembled state, the distal assembly means 98a of the adjustment element 318 engage with the coupling means 102 of the snap element 24 to irreversibly prevent movement of the adjustment element 318 from the assembled position to the pre-assembled position.

[0118] The distal assembly means 98a of the adjustment element 318 forms a latch portion of a latch mechanism 97 configured to prevent the adjustment element 318 from moving from an assembled position to a pre-assembled position relative to the housing 332. The coupling means 102 of the snap element 24 forms a latch counterpart of the latch mechanism 97 and the dose metering member 323 with the snap element 24 forms a counter member of the latch mechanism 97.

[0119] Figure 41 shows a detailed longitudinal section of the distal end of the second injection pen 300 in the assembled state during dose delivery, and Figure 42 shows a further detailed longitudinal section of the distal end of the second injection pen 300 in the assembled state during dose delivery. The longitudinal cuts shown in Figures 41 and 42 are oriented perpendicular to each other. Figures 41 and 42 thus show the injection pen 300 at the end of dose delivery, when the set dose has been completely expelled and the adjustment element 318 is still being pressed in the proximal direction 1 by the user of the injection pen 300.

[0120] During setting of a dose in the assembled state, the adjusting element 318 is rotationally coupled to the dose metering member 323 via a clutch mechanism 107 formed by teeth 108 on the inner surface of the dose setting element 22 (see Figure 5) and teeth 110 on the outer surface of the snap element 24 (see Figure 6). The dose setting element 22 forms a first clutch member of the clutch mechanism 107 and the snap element 24 forms a second clutch member of the clutch mechanism 107. Each of the dose metering members 23, 323 of the dose delivery mechanism 54, 354 forms a respective further member of the dose delivery mechanism 54, 354.

[0121] In each dose delivery mechanism 54, 354, the respective clutch mechanism 107 rotationally couples the respective adjustment element 18, 318 to the respective further member when the respective clutch mechanism 107 is in a closed state during dose setting in the assembled state, and rotationally decouples the respective adjustment element 18, 318 from the respective further member when the respective clutch mechanism 107 is in an open state during dose delivery in the assembled state.

[0122] In other embodiments of the clutch mechanism 107 for coupling the adjustment element 18, 318 to the further member, the second clutch member may be integrally formed with the further member, for example if the snap element 24 and the dose metering element 334 are integrally formed as a single-piece dose metering member 323, which constitutes the further member and at the same time the second clutch member.

[0123] During delivery of a dose, the clutch mechanism 107 is opened, thus rotationally decoupling the adjustment element 318 and the dose metering member 323. In the pre-assembled state, the clutch mechanism 107 is closed but the adjustment element 318 is rotationally decoupled from the clutch mechanism 107, such that the clutch mechanism 107 does not transmit the rotation of the adjustment element 318 to the dose metering member 323. In particular, the adjustment element 318 is rotationally decoupled from both the dose setting element 22 and the dose metering member 323 in the pre-assembled state.

[0124] During delivery of a dose in the assembled state, the adjustment element 318 is rotationally coupled to the housing 332 via the further clutch mechanism 113, which is formed by the teeth 108 on the inner surface of the dose setting element 22 and the teeth 114 located on the outer surface of the connector 26. The dose setting element 22 thereby forms a first clutch member of the further clutch mechanism 113, and the connector 26 forms a second clutch member of the further clutch mechanism 113. When the further clutch mechanism 113 is in a closed state and the first clutch member engages with the second clutch member, the adjustment element 318 is rotationally fixed to the additional member formed by the housing 332.

[0125] During setting of a dose, the further clutch mechanism 113 is opened, allowing rotation of the adjustment element 318 relative to the housing 332. During delivery of a dose, the further clutch mechanism 118 is disclosed, rotationally fixing the adjustment element relative to the housing. In the pre-assembled state, the adjustment element 318 is rotationally decoupled from the further clutch mechanism 113, as it can rotate relative to both the first clutch member formed by the dose setting element 22 and the second clutch member formed by the connector 26.

[0126] Figure 43 shows a longitudinal section of the dose setting element 22 of the injection pen 10 and the second injection pen 300, Figure 44 shows an oblique view of the longitudinal section of the dose setting element 22, Figure 45 shows an oblique view of the dose setting element 22 from the distal side, and Figure 46 shows an oblique view of the dose setting element 22 having the teeth 108 of the clutch mechanisms 107, 113 from the proximal side.

[0127] In both the clutch mechanism 107 and the further clutch mechanism 113, the clutch mechanism 107, 113 is in a closed state during one of setting a dose and delivering a dose, and the clutch mechanism 107, 113 is in an open state during the other of setting a dose and delivering a dose, such that the clutch mechanism 107 is closed when the further clutch mechanism 113 is open, and the clutch mechanism 107 is open when the further clutch mechanism 113 is closed.

[0128] Further, each clutch mechanism 107, 113 causes the adjustment element 318 to assume a dose setting position relative to the respective second clutch member 24, 26 during setting of a dose and a dose delivery position relative to the respective second clutch member 24, 26 during delivery of a dose, whereby the dose delivery position is axially offset relative to the dose setting position. Illustratively, the dose delivery position is axially offset in the proximal direction 1.

[0129] With the dose delivery mechanism 54,354 the further clutch mechanism 113 also forms a locking mechanism configured to rotationally lock the adjustment element 18,318 to the housing 32,332 upon delivery of a dose in the assembled state.

[0130] Each of the dose selectors 28 of the dose delivery mechanism 54, 354 forms a retaining member of the respective dose delivery mechanism 54, 354. Each adjustment element 18, 318 is located in a first axial position relative to the retaining member in a pre-assembled state, and each adjustment element 18, 318 is movable from the first axial position to a second axial position relative to the retaining member to move the respective dose delivery mechanism 54, 354 from the pre-assembled state to the assembled state. Each adjustment element 18, 318 is rotatable relative to the retaining member in the pre-assembled state.

[0131] During dose setting in the assembled state, each adjustment element 18, 318 is rotatable relative to its respective retaining member, and during dose delivery in the assembled state, each adjustment element 18, 318 is rotationally fixed relative to its respective retaining member. By the dose delivery mechanism 54, 354, each adjustment element 18, 318 is axially fixed relative to its respective retaining member in the assembled state.

[0132] Due to the dose delivery mechanism 54, 354, the first thread element formed by the piston rod 44 is axially immobile relative to a third element of the dose delivery mechanism 54, 354 during dose setting in the assembled state. The third element is thereby the housing 32, 332. Furthermore, the second thread element formed by the nut 38 moves axially relative to the third element during dose setting in the assembled state. During adjustment of the piston rod 44 in the pre-assembled state, the first thread element formed by the piston rod 44 moves axially relative to the third element formed by the housing 32, 332 and the second thread element formed by the nut 38 is axially immobile relative to the third element formed by the housing 302, 332.

[0133] The dose definition mechanism 115 acting between the snap element 24 of the dose delivery mechanism 54, 354 and the dose selector 28 is not effective in the pre-assembled state because the adjustment element 318 is rotationally decoupled from the snap element 24 and the snap element 24 does not rotate when the adjustment element 318 is rotated.

[0134] With both dose delivery mechanisms 54, 354, the adjustment element 18, 318 is configured to be rotated in a pre-assembled state after the medicament container 48, 348 is attached until the bearing 46 contacts the distal face of the plunger 210. A method of adjusting the position of the piston rod 44 in the pre-assembled state of the dose delivery mechanism 54, 354 can include attaching the medicament container 48, 348 to the housing 32, 332 and rotating the adjustment element 18, 318 until the bearing 46 contacts the distal face of the plunger 210. The adjustment element 18, 318 can then be rotated further until a predetermined torque is required for rotation. The dose delivery mechanism 54, 354 can then be transitioned from the pre-assembled state to the assembled state.

[0135] The adjustment element 18, 380 may be rotated until the bearing 46 is located at a distance greater than zero from the distal face of the plunger 210, thus forming a gap between the distal face of the plunger 210 and the proximal face of the bearing 46. The distance may be measured, for example, by measuring the position of the bearing 46 relative to the plunger 210 through the medicine container 305, which may be fabricated from a transparent material.

[0136] Alternatively, the method may further comprise adjusting the position of the piston rod 44 by rotating the adjustment element 18, 318 without attaching the medicament container 48, 348 to the housing 32, 332. The method may then comprise placing the pre-assembled dose delivery mechanism 54, 354 in an assembly jig and rotating the adjustment element 18, 318 until the proximal face of the bearing 46 contacts a reference surface provided by the assembly jig, which may then be located within the proximal cylindrical portion of the connector 43 of the injection pen 10.

[0137] For example, in the injection pen 300, the medication container 348 can be attached to the housing 332, and then the adjustment element 318 can be rotated until the bearing 46 contacts the distal face of the plunger 210. The adjustment element 318 can then be rotated further until a predetermined torque is required to rotate it.

[0138] With the dose delivery mechanism 54 of the injection pen 10, the proximal portion of the piston rod guide 42 forms a connector 43 configured to axially movably connect the medicine container 48 to the housing 32, so that the medicine container 48 can perform an axial movement from a receiving position to an operating position after connection to the housing 32. The receiving position is thereby defined by a snap element 234 of the connector 43 engaging with a distal opening 236 of the medicine container holder 50, 52. The operating position is defined by the snap element 234 engaging with a proximal opening 240 of the medicine container holder 50, 52 after screwing the medicine container holder 50, 52 into the connector 43.

[0139] In the injection pen 10, the dose delivery mechanism 54 can be provided without the medicament container holders 50, 52 attached to the housing 32, and the position of the piston rod 44 can be adjusted by rotating the adjustment element 18 before attaching the medicament container holders 50, 52 to the housing 32. For example, the dose delivery mechanism 54 can be placed in an assembly jig. The adjustment element 18 can then be rotated until the bearing 46 contacts a reference surface of the assembly jig and the bearing 46 and piston rod 44 reach a predetermined position relative to the housing 32.

[0140] This adjusts the piston rod 44 to a position relative to the housing 32 that ensures that the bearing 46 contacts the plunger 210 during movement of the medication container 48 from the receiving position to the operating position. Furthermore, the position of the piston rod 44 is adjusted to ensure that a quantity of liquid medication is expelled from the medication container 48 at the end of movement to the operating position. For example, the position may be adjusted such that medication is expelled only in the last quarter turn of the threading movement of the medication container holder 50, 52 into the proximal portion of the piston rod guide 42.

[0141] In both the first injection pen 10 and the second injection pen 300, the piston rod 44 can advance a first distance in the proximal direction 1 when the actuating member 18 moves a second distance in the proximal direction, the second distance being less than 1.5 times the first distance. In the first injection pen 10, the first distance is equal to the second distance. Moreover, the piston rod 44 moves the first distance when the actuating member 18 is moving the second distance. In the second injection pen 300, the ratio between the second distance and the first distance is given by the ratio between the pitch of the threaded connection 335 between the dose metering member 323 and the pitch of the further threaded connection 337 between the driver 336 and the housing 332.

[0142] An alternative embodiment of the second injection pen 300 may comprise a single threaded connection between all parts of the second injection pen 300 that rotate during dose delivery and the housing 332. Such an alternative embodiment may comprise the dose metering member 23 of the first injection pen 10. As with the first injection pen 10, the dose metering member 23 may comprise the driver 36, dose metering element 34, and snap element 24 shown in FIG.

[0143] Additionally or alternatively, the second injection pen 300 may further comprise the drug reconstitution unit 56 of the first injection pen 10. In that case, such a second injection pen 300 may be configured to receive a dual-chamber cartridge 48 and perform reconstitution of the lyophilized drug prior to delivery of the drug.

[0144] Additionally or alternatively, the second injection pen 300 may be further configured to permanently axially lock an actuation member, such as an actuation member formed by the adjustment element 318 and / or the dose setting element 22, to the dose metering member 323 upon delivery of a dose. In that case, the second injection pen 300 may comprise the coupling means 100 described in relation to the first injection pen 10.

[0145] Generally speaking, the first injection pen 10 and the second injection pen 300 may each comprise a blocking mechanism configured to prevent the setting and / or delivery of a second dose after the delivery of a first dose with the respective injection pen 10, 300. The blocking mechanism may be configured to permanently fix the dose setting element 22 at least rotationally to the housing 32, 332 when a dose is delivered, such as when a first set dose is delivered. Additionally or alternatively, the blocking mechanism may be configured to permanently fix the actuating member 18 axially to the counter member, whereby the actuating member 18 is moved relative to the counter member to initiate delivery of the set dose. In the injection pen 10, 300, the respective counter member is exemplarily formed by the dose metering member 23, 323.

[0146] The blocking mechanism may comprise a first blocking portion that engages with a second blocking portion to prevent setting and / or delivery of the second dose. In the first and second injection pens 10, 300, the first blocking portion is illustratively formed by the coupling means 100 and the second blocking portion is illustratively formed by the coupling means 102.

[0147] The injection pen 10, 300 may comprise a clutch mechanism having a closed state which rotationally locks the dose setting element 22 to the housing upon delivery of a dose. The blocking mechanism may permanently fix the dose setting element 22 at least rotationally to the housing 32, 332 by locking the clutch mechanism in the closed state. The clutch mechanism may be, for example, the clutch mechanism 107.

[0148] The clutch mechanism may comprise a first clutch portion, e.g., teeth 114 of the connector 26, which engages with a second clutch portion, e.g., teeth 108 of the dose setting element 22, in a closed state of the clutch mechanism and disengages from the second clutch portion in an open state of the clutch mechanism. For example, the first and second clutch portions may engage and disengage with relative axial movement relative to each other. The clutch mechanism may be locked in the closed state, e.g., by axially locking the first clutch portion to the second clutch portion.

[0149] Similar to the first injector pen 10, embodiments of the second injector pen 300 may be configured to inhibit a user from prematurely activating the second injector pen 300. Similar to the first injector pen 10, embodiments of the second injector pen 300 may be configured to axially lock the actuation member 318 relative to the housing 332 prior to setting and delivering the first dose. Similar to the first injector pen 10, the second injector pen 300 may include a knob cover 16 and / or a knob key 30.

[0150] Like the first injection pen 10, the second injection pen 300 may be preset to an injectable dose greater than zero as delivered. For example, the dose metering member 323 may be preset to a position corresponding to a set dose greater than zero. Like the first injection pen 10, the second injection pen 300 may be configured to prevent reduction of the preset injectable dose to zero.

[0151] In both the first and second injection pens 10, 300, the dose metering member 23, 323 is stopped in one rotational direction in a first angular position during setting of a dose and stopped in said rotational direction in a second angular position during delivery of the dose, the second angular position being rotationally spaced from the first angular position by a distance corresponding to a preset dose greater than zero. For example, the dose metering member 23, 323 may be in the second angular position at the end of delivery of the dose.

[0152] The first and second injection pens 10, 300 may comprise a first stopper limiting rotation in one direction of rotation in a first angular position during dose setting and / or a second stopper limiting rotation in said direction of rotation in a second angular position during dose delivery, e.g. at the end of dose delivery. The first stopper may for example be the stopper 126 shown in Figure 9 and / or the second stopper may for example be the end stoppers 174, 176 shown in Figures 13B and 15D.

[0153] In another embodiment, a stopper preventing rotation of the dose metering member 23, 323 at the end of dose delivery may be provided on each dose selector 28. The stopper may interact with a corresponding stopper provided on the dose metering member 23, 323, such as, for example, hard stopper 124. Such a stopper is disclosed in WO2020015980A1, the disclosure of which is incorporated by reference in its entirety into the present disclosure, including the stopper configuration referred to in WO2020015980A1 as a zero dose hard stopper.

[0154] Figure 47 shows a perspective view of a third injector pen 500 according to the present disclosure, Figure 48 shows an exploded view of the third injector pen 500, and Figure 49 shows a longitudinal cross-sectional view of the dose delivery mechanism 554 of the third injector pen 500 in an assembled state during setting of a dose. Unless a difference is disclosed in the specification or drawings, the third injector pen 500 is configured as disclosed for the second injector pen 300, and vice versa.

[0155] The dose delivery mechanism 554 comprises a housing 532 configured to be connected to a medicament container holder 505 via a non-releasable form-fit connection. The connection comprises a connector 506 disposed at a distal end of the medicament container holder 505. The connector 506 is configured to engage with a corresponding connector 543 located at a proximal end of the housing 532 (see FIG. 49). The connection is configured as a non-releasable snap fit connection.

[0156] The medication container holder 505 is configured to receive the medication container 348 already described in relation to the second injection pen 300. At the proximal end, the medication container holder 505 comprises a needle connector 306 configured to receive a double-ended needle assembly 501 having a double-ended cannula 502. The needle connector 300 is connected to the needle assembly 501 via a threaded connection. Alternatively, the connection may be configured as a luer lock, a snap-fit ​​connection, or the like. When the needle assembly 501 is mounted on the medication container holder 505, the distal end of the cannula 502 pierces the septum of the proximal needle end 349 of the medication container 348. The proximal end of the cannula 502 is covered by a needle cap 503 that is removed prior to use of the injection pen 500. A cap 504 covers the medication container holder 505 during storage of the injection pen 500.

[0157] The dose delivery mechanism 554 comprises a dose metering member 523 which is axially fixed and rotationally movable relative to the housing 532 by a rotatable fixation 560. Figure 50 shows a distal perspective view of the dose metering member 523 and Figure 51 shows a longitudinal section of the dose metering member 523. The rotatable fixation 560 comprises an annular rim 561 arranged at the proximal end of the dose metering member 523 and corresponding retaining lugs 533 at the proximal end of the housing 532. The retaining lugs 533 snap behind the annular rim 561, thus axially fixing the dose metering member 523 to the housing 532.

[0158] The dose delivery mechanism 554 further comprises a piston rod 44, shown in a perspective view in Fig. 52. The piston rod 44 is received in an opening 567 in the proximal end of the dose metering member 523. The piston rod 44 is thereby connected to the dose metering member 523 via a threaded connection 189. The threaded connection 189 comprises an internal thread in the opening 567 of the dose metering member 523 and an external thread on the outer periphery of the piston rod 44. The piston rod 44 forms a first threaded element of the threaded connection 189 and the dose metering member 523 forms a second threaded element of the threaded connection 189. At its proximal end, the piston rod 44 comprises coupling means 198 which axially fixedly and rotationally movablely connects the bearing 46 to the piston rod 44.

[0159] FIG. 53 shows a distal perspective view, FIG. 54 shows a distal view and FIG. 55 shows a proximal view of the extension 525 of the dose delivery mechanism 554. The extension 525 is received within the dose metering member 523. It is axially fixed and rotationally movable within the dose metering member 523 by a rotatable fastener 570. The rotatable fastener 570 illustratively comprises an annular ridge 571 arranged at the proximal end of the extension 525 and a corresponding lug 566 provided on the proximal end of the dose metering member 523. The lug 566 snaps behind the annular ridge 571 from the proximal side of the extension 525, thereby axially fixing the extension 525 to the dose metering member 523.

[0160] Piston rod 44 is axially movable and rotationally fixed relative to extension 525. The extension is provided at its proximal end with a non-circular opening 573 that matches a corresponding non-circular profile of piston rod 44. Piston rod 44 is received within opening 573, thereby allowing relative axial movement between piston rod 44 and extension 525 while rotationally locking piston rod 44 to extension 525.

[0161] Figure 56 shows a perspective view of the coupling element 520 of the dose delivery mechanism 554. The coupling element 520 comprises an end plate 580 disposed at its distal end and two bars 582 extending axially and parallel to each other in the proximal direction.

[0162] The coupling element 520 is rotationally fixed and axially movable relative to the piston rod 44. The coupling element 520 is thereby coupled to the piston rod 44 via the extension 525. As can be seen in FIG. 57, the bar 582 of the coupling element 520 is received between two ridges 575 of the extension 525 that extend radially from the inner surface of the extension 525. The ridges 575 thereby extend parallel to each other along the axial direction. The bar 582 and the ridges 575 provide an axially movable connection between the coupling element 520 and the extension 525 that rotationally fixes the coupling element 520 to the extension 525.

[0163] As can be further seen in Fig. 57, adjustment element 518 is fixed for axial and rotational movement to a distal end of coupling element 520. Fig. 58 shows a proximal perspective view of adjustment element 518, Fig. 59 shows a side view of adjustment element 518, Fig. 60 shows a cross-sectional view of adjustment element 518 taken along line AA in Fig. 59, and Fig. 61 shows a cross-sectional view of adjustment element 518 taken along line BB in Fig. 59.

[0164] The adjustment element 518 is fixed with respect to axial movement and rotation to the coupling element 520. Thus, the adjustment element 518 and the coupling element 520 form a single member of the dose delivery mechanism 554. As can be seen from FIG. 56, the coupling element 520 is part of the axial fixation acting between the adjustment element 518 and the coupling element 520 and comprises an axial fixing element 584 which engages with a corresponding axial fixing element provided on the adjustment element 518. Thereby, the axial fixing element 584 of the coupling element 520 is configured as a snap hook and the corresponding axial fixing element of the adjustment element 518 is configured as a periphery which engages with the snap hook. The coupling element 520 further comprises at least one rotation fixing element 585, for example several rotation fixing elements 585. The rotation fixing element 585 rotationally locks the adjustment element 518 to the coupling element 520 by engaging with a corresponding rotation fixing element provided on the adjustment element 518. The rotational fixing elements 585 of the coupling element 520 are configured as longitudinal ridges extending parallel to the axial direction, which are received between corresponding longitudinal recesses 586 provided in the adjustment element 518. In other embodiments of the dose delivery mechanism 554, the adjustment element 518 and the coupling element 520 may be configured as an integral, single member.

[0165] Figure 62 shows a perspective view of the coupling member 524 of the dose delivery mechanism 554. The coupling member 524 is configured as a hollow member. As can be seen from Figure 49, the coupling member 524 is located between the dose metering member 523 and the extension 525. The coupling member 524 is thereby arranged in the dose metering member 523 and receives the extension 525 in its internal cavity. The coupling member 524 is rotationally fixed to the dose metering member 523 via an axially movable rotational fixing part 563. The rotational fixing part 563 comprises a longitudinal recess 590 on an outer surface of the coupling member 524 which engages with a corresponding longitudinal ridge 564 on an inner surface of the dose metering member 523 (see Figures 50 and 51).

[0166] Figure 63 shows a distal perspective view of the sleeve 528 of the dose delivery mechanism 554, and Figure 64 shows a longitudinal cross-sectional view of the sleeve 528. The sleeve 528 is configured as a hollow member. As can be seen in Figure 49, the sleeve 528 is located between the housing 532 and the dose metering member 523.

[0167] The sleeve 528 is threadably connected to and threadably engages the dose metering member 523. The threaded connection between the sleeve 528 and the dose metering member 523 comprises an internal thread 612 on the inner surface of the sleeve 528 which engages with an external thread 562 on the outer surface of the dose metering member 523.

[0168] Furthermore, the sleeve 528 is rotationally fixedly and axially movably connected to the housing 532. The connection between the sleeve 528 and the housing 532 thereby comprises a connector 620. The connector 620 is located at a distal end of the housing 532. It is axially and rotationally fixed relative to the housing 532. In other embodiments, the connector 620 may be formed integrally with the housing 532. The connector 620 comprises a pair of radial lugs 622 provided on an outer surface of the connector 620. The radial lugs 622 engage with corresponding openings 535 accessible in an inner surface of the housing 532. The connector 620 further comprises an outer annular rim 626 provided at a distal end of the connector 620. The annular rim 626 abuts against a distal surface of the housing 532 to prevent the connector 620 from moving in a proximal direction.

[0169] The inner surface of connector 620 is provided with a longitudinal recess 624 that engages with a corresponding longitudinal ridge 616 on the outer surface of sleeve 528. This provides a rotationally fixed, axially movable connection between housing 532 and sleeve 528.

[0170] The dose sleeve 523 is configured as a dose indicating member and is provided with markings on its outer surface serving to indicate the set dose. A window 610 is formed in the sleeve 528 through which the dose sleeve 523 is visible. The window 610 of the sleeve 528 is aligned with a housing window 534 provided in the housing 532 such that the dose sleeve 523 is visible from outside the housing 532. The set dose is thus indicated by markings visible through the windows 534, 610.

[0171] Coupling member 524 is axially fixed and rotationally movable relative to sleeve 528. The connection between coupling member 524 and sleeve 528 comprises a connector 527.

[0172] Fig. 66 shows a perspective view of connector 527, and Fig. 67 shows a perspective view of a longitudinal section of connector 527. Connector 527 is axially and rotationally fixed relative to sleeve 528. Connector 527 includes longitudinal ridges 632 on its outer surface that engage corresponding recesses 618 (see Fig. 64) on the inner surface of sleeve 528. Additionally, connector 527 includes radially extending lugs 630 that engage accessible openings 614 in the inner surface of sleeve 528. This engagement prevents removal of connector 527 from sleeve 528.

[0173] A distal blocking element 635 and a proximal blocking element 654 are formed on an inner surface of connector 527. The blocking elements 635, 654 provide an axially fixed and rotationally movable connection to coupling member 524 such that a radially extending annular rim 592 (see FIG. 62 ) on an outer surface of coupling member 524 is received between the blocking elements 635, 654.

[0174] Furthermore, a radial stopper 568 is formed between the sleeve 528 and the dose metering member 523. This radial stopper 568 is configured to stop relative rotation between the dose metering member 523 and the sleeve 528, and thus between the dose metering member 523 and the housing 532, at the end of the delivery of the dose. The radial stopper 568 comprises at least one stopper surface 569 provided on the dose metering member 523 and a corresponding stopper surface 636 provided on the connector 527. The stopper surfaces 569, 636 are oriented parallel to each other and configured to engage with each other at the end of the delivery of the dose. The stopper surfaces 569, 636 form an angle with a radial plane oriented perpendicular to the longitudinal axis of the dose delivery mechanism 554. In the third injection pen 500, the stopper surfaces 569, 636 are oriented parallel to the longitudinal axis. Although the stop surface 636 is provided on the connector 527, in other embodiments the stop surface 636 may be provided directly on the sleeve 528.

[0175] In the third injection pen 500, the adjustment element 518 forms the dose setting member of the dose delivery mechanism 554. To set the dose to be delivered, the user rotates the adjustment element 518 relative to the housing 532 in the assembled state.

[0176] Fig. 68 shows a side view of the third injection pen 500 in an assembled state during dose setting when no dose has been set. Fig. 69 shows a side view of the third injection pen 500 in a pre-assembled state. In the pre-assembled state, the adjustment element 518 is in a pre-assembled position relative to the housing 532, and during dose setting and in the assembled state when no dose has been set, the adjustment element 518 is in an assembled position relative to the housing 532. This causes the assembled position to be more proximal than the pre-assembled position.

[0177] Figure 70 shows a detailed longitudinal cross-sectional view of the distal end of the third injection pen 500 in the assembled state during dose setting, and Figure 71 shows a further detailed longitudinal cross-sectional view of the distal end of the third injection pen 500 in the assembled state during dose setting, whereby the longitudinal cross-section of the view shown in Figure 71 is oriented perpendicular to the longitudinal cross-section of the view shown in Figure 70.

[0178] During dose setting, the adjusting element 518 is rotationally fixed relative to the coupling member 524 by the clutch mechanism 507. Rotation of the adjusting element 518 thus causes rotation of the piston rod 44 due to rotational fixation via the extension 525 and the coupling element 520, and a simultaneous rotation of the dose metering member 523 due to rotational fixation via the coupling element 520, the clutch mechanism 507 and the coupling member 524. As both the piston rod 44 and the dose metering member 523 rotate relative to the housing 532 at the same speed during dose setting, the axial position of the piston rod 44 relative to the housing 532 does not change despite the threaded connection 189 between the piston rod 44 and the dose metering member 523.

[0179] Rotation of dose metering member 523 relative to sleeve 528 during setting a dose causes sleeve 528 to move axially distally relative to housing 532 due to threaded connections 562, 612. This also causes distal movement of adjustment element 518 and coupling element 520. Furthermore, coupling member 524 also moves distally due to its axially fixed, rotationally movable connection to sleeve 528 via connector 527.

[0180] As can be seen in Figures 70 and 71, the adjustment element 518 is coupled to the sleeve 528 by a latch mechanism 597 that prevents distal movement of the adjustment element 518 and the coupling element 520 relative to the sleeve 528. As can be seen in Figures 58-61, 63, and 64, the latch mechanism 597 comprises a latch portion 600 located at a proximal end of the adjustment element 518 that engages with a latch counterpart 529 of the sleeve 528. The latch counterpart 529 of the sleeve 528 is configured as an annular edge located on an outer surface of the sleeve 528. The latch portion 600 of the adjustment element 518 is configured as a corresponding radial lug provided on an inner surface of the adjustment element 518. In the assembled position of the adjustment element 518, the radial lug 600 engages the annular edge 529, thus preventing the adjustment element 518 from moving further distally towards the pre-assembled state.

[0181] Adjustment element 518 and coupling element 520 are configured as compression springs and are biased distally against sleeve 528 by biasing member 250, shown in FIG. 48 and not visible in FIGS. 70 and 71.

[0182] Upon rotation of the dose metering member 523 and axial movement of the sleeve 528 relative to the housing 532 during setting of a dose, the window 610 in the sleeve 528 moves axially along the dose metering member 523. This causes the respective markings on the dose sleeve 523 visible through the window 610 to indicate the dose currently being set.

[0183] To deliver a set dose, a user of the third injection pen 500 pushes the adjustment element 518 and the coupling element 520 in the proximal direction 1 against the force of the biasing member 250 .

[0184] Figure 72 shows a detailed longitudinal section of the distal end of the third injection pen 500 in the assembled state during dose delivery, and Figure 73 shows a further detailed longitudinal section of the distal end of the third injection pen 500 in the assembled state during dose delivery, whereby the longitudinal section is oriented perpendicular to the longitudinal section of the view in Figure 73. Figures 72 and 73 thus show the dose delivery mechanism 554 of the third injection pen 500 at the end of dose delivery, when the set dose has been fully expelled and the user is still pushing the adjustment element 518 and the coupling element 520 in the proximal direction.

[0185] During dose delivery, the adjustment element 518 and the coupling element 520 are rotationally locked to the housing 532 via the sleeve 528 because proximal movement of the coupling element 520 and the adjustment element 518 relative to the sleeve 528 at the start of dose delivery closes the clutch mechanism 513 between the adjustment element 518 and the sleeve 528. The clutch mechanism 513 comprises teeth 515 formed on the adjustment element 518 and corresponding teeth 514 formed on the distal end of the sleeve 528. Furthermore, the clutch mechanism 513, via the extension 525, the coupling element 520, the adjustment element 518 and the sleeve 528, rotationally locks the piston rod 44 to the housing 532 during dose delivery.

[0186] When the coupling element 520 moves proximally relative to the coupling member 524 at the start of dose delivery, the clutch mechanism 507 between the coupling element 520 and the coupling member 524 opens, allowing the coupling member 524 to rotate relative to the coupling element 520. After the clutch mechanism 507 is disengaged, further proximal movement of the coupling element 520 pushes the sleeve 528 in the proximal direction 1. The proximal movement of the sleeve 528 rotates the dose metering member 523 via the threaded connection 612 between the sleeve 528 and the dose metering member 523. Since the piston rod 44 is rotationally locked to the housing 332 during dose delivery, the rotation of the dose metering member 523 causes a proximal movement of the piston rod 44, which is driven via the threaded connection 189.

[0187] Figure 74 shows a detailed longitudinal cross-sectional view of the distal end of the third injection pen 500 in a pre-assembled state of the dose delivery mechanism 554, and Figure 75 shows a further detailed longitudinal cross-sectional view of the distal end of the third injection pen 500 in a pre-assembled state, whereby the longitudinal cross-section is oriented perpendicular to the longitudinal cross-section of the view in Figure 74.

[0188] In the pre-assembled state, adjustment element 518 and coupling element 520 are located in an adjusted position relative to housing 532 and sleeve 528. In the adjusted position, adjustment element 518 and coupling element 520 are displaced distally relative to their respective assembled positions in the assembled state.

[0189] The dose delivery mechanism 554 comprises a further latch mechanism 599 which prevents the adjustment element 518 and the coupling element 520 from disengaging in a pre-assembled state. The further latch mechanism 599 comprises a latch portion 600 of the adjustment element 518 and a further latch counterpart 530 arranged at the distal end of the sleeve 528 such that the further latch counterpart 530 is located distal to the latch counterpart 529.

[0190] The further latch counterpart 530 is configured as an angled recess that receives a radial lug of the latch portion 600 of the adjustment element 518. The latch portion 600 formed by the radial lug thereby releasably engages the further latch counterpart 530 and prevents distal movement of the adjustment element 518 while allowing proximal movement.

[0191] In the pre-assembled state, the clutch mechanism 507 between the coupling element 520 and the coupling member 524 is opened, thus rotationally decoupling the adjustment element 518 from the dose metering member 523. At the same time, the adjustment element 518 is rotationally coupled and rotationally fixed to the piston rod 44 by the coupling element 520 and the extension 525. Rotation of the adjustment element 518 relative to the housing 532 thereby causes the piston rod 44 to rotate relative to the housing 532 and the dose metering member 523. Due to the threaded connection 189 between the dose metering member 523 and the piston rod 44, the piston rod 44 moves axially relative to the housing 332 upon rotation of the adjustment element 518.

[0192] In the clutch mechanism 507, the coupling element 520 forms a first clutch member of the clutch mechanism 507 and the coupling member 524 forms a second clutch member of the clutch mechanism 507. The dose metering member 523 of the dose delivery mechanism 554 forms a further member of the dose delivery mechanism 54, 354 to which the adjustment element 518 rotationally couples during setting of a dose in the assembled state and to which the adjustment element 518 rotationally decouples during delivery of a dose in the assembled state.

[0193] The coupling element 520 comprises a first clutch portion 508 of the clutch mechanism 507. The first clutch portion 508 is configured as radial teeth on an outer surface of the coupling element 520. The coupling member 524 comprises a second clutch portion 509 of the clutch mechanism 507. The second clutch portion 509 is configured as radial teeth on an inner surface of the coupling member 524. In a closed state of the clutch mechanism 507, the first clutch portion 508 engages with the second clutch portion 509, as shown in FIG. 71.

[0194] During adjustment of the piston rod in the pre-assembled state, the clutch mechanism 507 is in an open state, whereby the first clutch part 508 and the second clutch part 509 are disengaged by being axially spaced apart from each other. This causes the first clutch part 508 to be displaced distally from the second clutch part 509, the distal direction being opposite to the proximal direction 1 (see FIG. 74). During delivery of a dose in the assembled state, the clutch mechanism 507 is also in an open state, whereby the first clutch part 508 and the second clutch part 509 are disengaged by being axially spaced apart from each other, whereby the second clutch part 509 is displaced proximally from the first clutch part 508 (see FIG. 72).

[0195] Furthermore, the adjustment element 518 forms a first clutch member of the clutch mechanism 513 and the sleeve 528 forms a second clutch member of the clutch mechanism 513. The housing 532 of the dose delivery mechanism 554 forms a further member of the dose delivery mechanism 554 to which the adjustment element 518 rotationally couples during setting of a dose in the assembled state and to which the adjustment element 518 rotationally disengages during delivery of a dose in the assembled state.

[0196] The sleeve 528 forms a retaining member for the adjustment element 518 .

[0197] The dose delivery mechanism 554 comprises a dose defining mechanism 115 that defines a dose that can be set by a user. An engagement mechanism 116 of the dose defining mechanism 115 is provided on the adjustment element 518 (see FIG. 58). The engagement mechanism 116 is configured as a radially extending lug that is radially flexible. The engagement mechanism 116 engages with a corresponding dose stopper 118 provided on the distal end of the sleeve 528 (see FIGS. 63 and 64). The dose stopper 118 is configured as a longitudinal recess formed on the inner surface of the sleeve 528. During setting of a dose, the adjustment element 518 and the coupling element 520 are configured to perform multiple complete rotations about the longitudinal axis of the dose delivery mechanism 554.

[0198] Upon adjustment of the piston rod 44 in the pre-assembled state, the dose defining feature 115 of the dose delivery mechanism 554 is not effective because the engagement feature 116 is axially displaced relative to the dose stopper 118, causing the engagement feature 116 and the dose stopper 118 to disengage from each other (see Figure 75).

[0199] In the dose delivery mechanism 554, the housing 532 forms a third element, relative to which a first thread element formed by the piston rod 44 rotates during adjustment of the piston rod in the pre-assembled state, and a second thread element formed by the dose metering member 523 is rotationally fixed relative to the third element. During delivery of a dose in the assembled state, the first thread element formed by the piston rod 44 is rotationally fixed relative to the third element formed by the housing 532, and the second thread element formed by the dose metering member 523 rotates relative to the third element.

[0200] In the third injection pen 500, the piston rod 44 may be configured to advance a first distance in the proximal direction 1 when the actuating member 520 moves a second distance in the proximal direction, the second distance being less than 1.5 times the first distance. In the third injection pen 500, the ratio between the second distance and the first distance is given by the ratio of the pitch of the threaded connection 189 between the piston rod 44 and the dose metering member 523 and the pitch of the further threaded connection 562 between the sleeve 528 and the dose metering member 523.

[0201] Additionally or alternatively, the third injection pen 500 may further comprise the drug reconstitution unit 56 of the first injection pen 10. In that case, such a third injection pen 500 may be configured to receive the dual-chamber cartridge 48 and perform reconstitution of the lyophilized drug prior to delivery of the drug.

[0202] Similar to the first injector pen 10, embodiments of the third injector pen 500 may be configured to inhibit a user from prematurely activating the third injector pen 500. Similar to the first injector pen 10, embodiments of the third injector pen 500 may be configured to axially lock the actuation member 520 relative to the housing 532 prior to setting and delivering the first dose. Similar to the first injector pen 10, the third injector pen 500 may include a knob cover 16 and / or a knob key 30.

[0203] FIG. 76 shows a perspective view of a fourth injector pen 700 according to the present disclosure. The fourth injector pen 700 is a variant of the third injector pen 500. Unless differences are disclosed in the specification or drawings, the fourth injector pen 700 is configured as disclosed for the third injector pen 500 and vice versa. In the following, components of the fourth injector pen 700 that perform the same function as corresponding components of the third injector pen 500 are provided with the same reference numerals. However, these components may differ in shape and / or appearance between the third injector pen 500 and the fourth injector pen 700.

[0204] 77 shows a side view of the fourth injection pen 700 in an assembled state during dose setting, whereby no dose is set and the adjustment element 518 of the dose delivery mechanism 754 of the fourth injection pen 700 is in an assembled position relative to the housing 532 of the dose delivery mechanism 754.

[0205] 78 shows a side view of the fourth injection pen 700 in a preassembled state with the adjustment element 518 in a preassembled position relative to the housing 532. In the preassembled position, the adjustment element 518 is offset distally from its assembled position, such that the distal direction is oriented perpendicular to the proximal direction 1.

[0206] 79 shows a side view of the fourth injection pen in a pre-assembled state with the adjustment element 518 in the adjustment position, in which the adjustment element 518 is displaced proximally compared to the pre-assembled position.

[0207] FIG. 80 shows an exploded view of the fourth injection pen 700, and FIG. 81 shows a longitudinal cross-section of the dose delivery mechanism 754 of the fourth injection pen 700 in an assembled state during dose setting when no dose has been set.

[0208] Similar to the dose delivery mechanism 554 of the third injection pen 500, the dose delivery mechanism 754 of the fourth injection pen 700 comprises a coupling element 720 that is rotationally fixed and axially movable relative to the piston rod 44. Unlike the dose delivery mechanism 554, the dose delivery mechanism 754 does not comprise an extension 525. Instead, the coupling element 720 directly engages the piston rod 44 in a manner that rotationally fixes the coupling element 720 to the piston rod 44 and allows axial movement between the coupling element 720 and the piston rod 44.

[0209] The dose delivery mechanism 754 further comprises a biasing element in the form of a spring, not shown in Figures 80 and 81. The biasing element biases the adjustment element 518 in a distal direction in both the pre-assembled and assembled states of the dose delivery mechanism 754.

[0210] Fig. 82 shows a perspective view of the coupling element 720 of the dose delivery mechanism 754, and Fig. 83 shows a cross-section of the coupling element 720 along line AA shown in Fig. 82. The coupling element 720 is configured as a tubular member extending along a longitudinal direction. It has a non-circular inner cross-section configured to receive the piston rod 44. The piston rod 44 shown in Fig. 84 has a distal portion 45 having a profile configured to engage with the non-circular inner cross-section of the coupling element 720 to rotationally lock the piston rod 44 and the coupling element 720 while allowing axial movement between the coupling element 720 and the piston rod 44.

[0211] 85-89 show the adjustment element 518 of the dose delivery mechanism 754. The adjustment element 518 engages with a distal portion of the coupling element 720, whereby the adjustment element 518 is rotationally fixed relative to the coupling element 720 in both the pre-assembled and assembled states of the dose delivery mechanism 704. The rotational lock between the coupling element 720 and the adjustment element 518 comprises a non-circular outer cross-section of the coupling element 720 which conformally engages with a corresponding inner shape of a central opening 519 of the adjustment element 518.

[0212] A latch mechanism 597 acts between the coupling element 720 and the adjustment element 518. In the assembled state of the dose delivery mechanism 754, the latch mechanism 597 prevents the adjustment element 518 from moving distally from an assembled position to a pre-assembled position relative to the housing 532. The latch mechanism 597 comprises a latch portion 600 formed on the adjustment element 518 and a latch counterpart 529 formed on the coupling element 720. The latch portion 600 is configured as a flexible hook that protrudes radially inwardly from an inner surface of the adjustment element 518 at the opening 519. The latch counterpart 529 is configured as a recess located on an outer surface of a distal portion of the coupling element 720.

[0213] The coupling element 720 may form a retaining member of the dose delivery mechanism 754 .

[0214] In the pre-assembled state of the dose delivery mechanism 754, the adjustment element 518 is located in a more distal position relative to the coupling element 720 compared to the assembled state. In this position, the further latch mechanism 599 prevents the adjustment element 518 from disengaging from the dose delivery mechanism 754 and the coupling element 720. The further latch portion of the further latch mechanism 599 is formed by the latch portion 600 and the further latch counterpart 530 of the further latch mechanism 599 is formed by an additional recess in the outer surface of the coupling element 720. This results in the further latch counterpart 530 being located more distally than the latch counterpart 529.

[0215] Figures 90-93 show a sleeve 528 of a dose delivery mechanism 754 which is rotationally fixed but axially movable relative to a housing 532. The sleeve 528 includes a longitudinal recess on its outer surface which engages a corresponding longitudinal ridge on the inner surface of the housing 532 to rotationally fix the sleeve 528 to the housing 532. The sleeve 528 includes an outer portion 528a and an insert 528b which is rotationally and axially fixed inside the outer portion 528a at a distal end of the outer portion 528a.

[0216] A dose defining mechanism 115 of the dose delivery mechanism 754 acts between the adjustment element 518 and the sleeve 528. The dose defining mechanism 115 is configured as a flexible hook and comprises an engagement mechanism 116 provided at the proximal end of the adjustment element 518. The engagement mechanism 116 interacts with a dose stopper 118 provided at a proximal portion of the inner surface of the insert 528b of the sleeve 528.

[0217] The dose delivery mechanism 754 further comprises a clutch mechanism 513 acting between the adjustment element 518 and the sleeve 528. The clutch mechanism 513 comprises teeth 515 disposed on a proximal outer surface of the adjustment element 518. When the clutch mechanism 513 is in a closed state, the teeth 515 engage corresponding teeth 514 provided on a distal portion of an inner surface of the insert 528b, whereby the inner surface is a side of a cavity formed in the distal end of the insert 528b and the sleeve 528.

[0218] The adjustment element 518 forms a first clutch member of the clutch mechanism 513 and the sleeve 528 forms a second clutch member of the clutch mechanism 513. The housing 532 of the dose delivery mechanism 754 forms a further member of the dose delivery mechanism 754 to which the adjustment element 518 is rotationally coupled during setting of a dose in the assembled state and to which the adjustment element 518 is rotationally decoupled during delivery of a dose in the assembled state. Furthermore, the clutch mechanism 513 forms a locking mechanism which rotationally locks the adjustment element 718 to the housing 532 during delivery of a dose in the assembled state of the dose delivery mechanism 754.

[0219] Figures 94-96 show the coupling member 524 of the dose delivery mechanism 754. The coupling member 524 is axially secured to the sleeve 528 by a rim 592 at the distal end of the coupling member 524. The rim 592 is held between a proximal blocking element 634 and a distal blocking element 635 at the proximal end of the insert 528b. The proximal blocking element 634 is configured as a flexible hook and the distal blocking element 635 is formed by a radial surface of the insert 528b.

[0220] A clutch mechanism 507 acts between the coupling member 524 and a coupling element 720 housed within the coupling member 524. The clutch mechanism 507 comprises a first clutch portion 508 disposed on an outer surface of the coupling element 720 and comprising longitudinal teeth. The clutch mechanism 507 further comprises a second clutch portion 509 located on an inner surface of the coupling member 524. The second clutch portion 509 is configured as longitudinal teeth that mesh with the longitudinal teeth of the first clutch portion 508 in a clutch closed state.

[0221] The coupling element 520 forms a first clutch member of the clutch mechanism 507 and the coupling member 524 forms a second clutch member of the clutch mechanism 507. The dose metering member 523 of the dose delivery mechanism 754 forms a further member of the dose delivery mechanism 754 to which the adjustment element 518 rotationally couples during setting of a dose in the assembled state and to which the adjustment element 518 rotationally decouples during delivery of a dose in the assembled state.

[0222] Figures 97 and 98 show the dose metering member 523 of the dose delivery mechanism 754. Between the dose metering member 523 and the insert 528b of the sleeve 528 a radial stopper 568 is provided. The radial stopper 568 comprises a stopper surface 636 located on a proximal extension of the insert 528b and a corresponding stopper surface 569 located on the distal end of the dose metering member 523.

[0223] As can be seen from Figures 99 and 100, which show the dose delivery mechanism 754 in an assembled state during dose setting where no dose has been set, during dose setting the clutch mechanism 507 between the coupling element 720 and the coupling member 524 is closed and the clutch mechanism 513 between the adjustment element 518 and the sleeve 528 is opened. Dose setting is then achieved by rotating the adjustment element 720 in the same manner as described for the third injection pen 500.

[0224] Figures 101 and 102 show the dose delivery mechanism 754 in the assembled state during dose delivery when the set dose has been fully expelled and the user is still pushing the adjustment element 518 in the proximal direction 1. During dose delivery, the clutch mechanism 507 is opened, thus allowing rotation between the piston rod 44 and the dose metering member 523, and the clutch mechanism 513 is closed, thus rotationally locking the piston rod 44 to the housing 532.

[0225] 103 and 104 show the dose delivery mechanism 754 in a pre-assembled state. Compared to the assembled state, the adjustment element 518 is displaced distally relative to the coupling element 720 and the housing 532. Thus, the latch portion 600 of the adjustment element 518 engages with a further latch counterpart 530 provided on the coupling element 720 distally of the latch counterpart 529. In the state shown in FIGS. 103 and 104, the adjustment element 518 is located in a pre-assembled position relative to the housing 532.

[0226] To adjust the position of the piston rod 44 in the pre-assembled state, the adjustment element 518 is pushed in the proximal direction 1 from the pre-assembled position to the adjustment position against the biasing force of a spring acting between the adjustment element 518 and the sleeve 528, as shown in Figs. 105 and 106. The proximal movement of the adjustment element 518 results in a proximal movement of the coupling element 720 and an opening of the clutch mechanism 507. At the same time, the clutch mechanism 513 remains open, preventing the teeth 515 of the adjustment element 518 from engaging with the teeth 514 of the sleeve 528. This is due to the axial misalignment between the teeth 513 and 514.

[0227] When an assembler of the fourth injection pen 700 rotates the adjustment element 518 in the adjustment position shown in Figures 105 and 106, the piston rod 44 rotates with the adjustment element 518 and the dose metering member 523 does not rotate due to the open clutch mechanism 507. Rotation of the piston rod 44 relative to the dose metering member 523 thereby causes axial movement of the piston rod 44 relative to the housing 532 via the threaded connection 189.

[0228] In the fourth injection pen 700, the piston rod 44 may be configured to advance a first distance in the proximal direction 1 when the actuating member 518 moves a second distance in the proximal direction, the second distance being less than 1.5 times the first distance. In the fourth injection pen 700, the ratio between the second distance and the first distance is given by the ratio of the pitch of the threaded connection 189 between the piston rod 44 and the dose metering member 523 and the pitch of the further threaded connection 562 between the sleeve 528 and the dose metering member 523.

[0229] Additionally or alternatively, the fourth injection pen 700 may further comprise the drug reconstitution unit 56 of the first injection pen 10. In that case, such a fourth injection pen 700 may be configured to receive a dual-chamber cartridge 48 and perform reconstitution of the lyophilized drug prior to delivery of the drug.

[0230] Similar to the first injector pen 10, embodiments of the fourth injector pen 700 may be configured to inhibit a user from prematurely activating the fourth injector pen 700. Similar to the first injector pen 10, embodiments of the fourth injector pen 700 may be configured to axially lock the actuation member 520 relative to the housing 532 prior to setting and delivering the first dose. Similar to the first injector pen 10, the fourth injector pen 700 may include a knob cover 16 and / or a knob key 30.

[0231] The mechanism may include a dose definition mechanism that allows a user of the device to set at least one dose of the medicament for delivery. For example, the dose definition mechanism may be configured to allow only a single predetermined dose to be set. Alternatively, the dose definition mechanism may be configured to allow a user to set a number of different predetermined doses, such as two or more different doses.

[0232] In the injection pen 10, 300, 500, 700, each dose delivery mechanism 54, 354, 554, 754 comprises a dose defining mechanism 115 which acts between the respective dose setting element 18, 318, 518 and the housing 32, 332, 532 during setting of a dose. Thus, the dose defining mechanism 115 has at least one dose stopper 118 and a counter element 116 which is configured to rotate relative to the dose stopper 118 when the dose setting element 38, 318, 518 rotates during setting of a dose, and which is configured to engage with the dose stopper 118 when a dose is set. The counter element 116 is formed by the respective engagement mechanism 116 of the dose delivery mechanism 54, 354, 554, 754.

[0233] The dose defining mechanism 115 can define a rotational position of the dose setting element 22, 518 relative to the housing 32, 332, 532 that corresponds to a settable dose. For each settable dose, the dose defining mechanism 115 can comprise a separate dose stopper 118. In that case, the dose setting element 22, 518 can be configured to rotate less than one revolution when setting the dose. In the third and fourth injection pens 500, 700, the dose defining mechanism 115 can comprise individual dose stops 118 defining more than one dose, e.g., the individual dose stoppers 118 can be configured to engage with the counter element 116 once for each revolution of the counter element 116 relative to the dose stopper 118.

[0234] The counter element 116 may be configured as a flexible element which snaps onto the dose stopper 118 when the dose is set. For example, the counter element 116 may be configured as a flexible protrusion on a component of the respective dose delivery mechanism 54, 354, 554, 754. The counter element 116 may for example be integrally formed with the component of the respective dose delivery mechanism 54, 354, 554, 754 to which it is fixed. In the first and second injection pens 10, 300 this component is formed by the dose metering member 23, 323 and in the third and fourth injection pens 500, 700 it is formed by the dose setting element 518.

[0235] In the first and second injection pens 10, 300, engagement of the counter element 116 with the dose stop 118 prevents the spring 40 from releasing the energy stored during rotation of the dose setting element 22 when setting a dose. This enables the dose definition mechanism 115 to provide a latching function that keeps the spring 40 in a tensioned state until a dose is delivered by transitioning the respective dose delivery mechanism 54, 354 from a dose setting state to a dose delivery state.

[0236] In the first and second injection pens 10, 300, the counter element 116 is configured to disengage from the dose stop 118 when the respective dose delivery mechanism 54, 354 transitions from the dose setting state to the dose delivery state. This prevents the dose definition mechanism 115 from interfering with the delivery of the set dose. Furthermore, it may allow the spring 40 to release the energy stored during rotation during the setting of the dose. In an embodiment having multiple dose stops 118, the counter element 116 may be configured to disengage from all the dose stops 118 when the respective dose delivery mechanism 54, 354 transitions to the dose delivery state. This allows the counter element 116 to rotate back to its initial position during the delivery of the dose without interfering with the dose stop 118. The initial position may correspond to a zero dose position where no dose is set.

[0237] For example, the counter element 116 may be configured to move out of engagement with the dose stopper 118 by axially moving relative to the dose stopper 118 .

[0238] In the injection pen 10, 300, 500, 700, one of the dose stopper 118 and the counter element 116, e.g. the dose stopper 118, is rotationally fixed relative to the housing 32, 332, 532. Thus, one of the dose stopper 118 and the counter element 116 may be axially movable relative to the dose setting element 22, 518.

[0239] In the first and second injection pens 10, 300, one of the dose stopper 118 and the counter element 116, e.g. the dose stopper 118, is axially fixed relative to the button 18, 318. This allows the dose stopper 118 and one of the counter element 116 to move together with the button 18, 318 when the respective dose delivery mechanism 54, 354 moves from a dose setting state to a dose delivery state. This movement allows the dose stopper 118 and one of the counter element 116 to move out of engagement with the other of the dose stopper 118 and the counter element 116. For example, the dose stopper 118 and one of the counter element 116 may be linearly guided in the housing 32, 332.

[0240] In some embodiments, one of the dose stopper 118 and the counter element 116 is fixed to an outer housing part of the respective dose delivery mechanism 54, 354, 554, 754. The outer housing part may be fixed to a connection for coupling the medicament container 48, 348 to the respective dose delivery mechanism 54, 354, 554, 754. Alternatively, the outer housing part may be movable relative to the connection, such as axially movable. Furthermore, the outer housing part may be rotationally fixed relative to the connection. For example, the outer housing part may be a housing connector, such as a housing connector that engages with the housing 32, 332, 532 via an axially movable and rotationally fixed connection. In the first and second injection pens 10, 300, the outer housing part is formed by the dose selector 28, and in the third and fourth injection pens 500, 700, the outer housing part is formed by the sleeve 528.

[0241] In the first and second injection pens 10, 300, the dose defining mechanism 115 acts between the dose metering member 23, 332 and the housing 32, 332, 532. It thus defines a rotational position of the dose metering member 23, 332 relative to the housing 32, 332 that corresponds to a settable dose.

[0242] In the first and second injection pens 10, 300, the other of the dose stopper 118 and the counter element 116, e.g. the counter element 116, is rotationally fixed relative to the dose metering member 23, 332. Illustratively, the other of the dose stopper 118 and the counter element 116 is permanently rotationally fixed relative to the dose metering member 23, 332. The other of the dose stopper 118 and the counter element 116 is further fixed to the dose metering member 23, 332, e.g. a first part of the dose metering member 23, 332 which is movable relative to the housing 32, 332, 532.

[0243] In the first, second, third and fourth injection pens 10, 300, 500, 700, the other of the dose stopper 118 and the counter element 116, e.g. the counter element 116, is axially movable relative to the button 18, 318, 518. One of the dose stopper 118 and the counter element 116, e.g. the dose stopper 118, is axially fixed relative to the button 18, 318, 518. This allows the dose stopper 118 to be disengaged from the counter element 116 by moving the button relative to the housing 32, 332, 532, as in the first and second injection pens 10, 300.

[0244] In the second injection pen 300, the dose delivery mechanism 354 comprises a blocking mechanism having a first element and a second element, the first element engaging with the second element when the button 318 is released during dose delivery to prevent the respective dose delivery mechanism 354 from transitioning from the dose delivery state to the dose setting state. This keeps the respective dose delivery mechanism 354 in the dose delivery state and prevents a change in the dose setting upon interruption of the dose delivery due to the torque provided by the spring 40. The blocking mechanism can block distal movement of the button 318 against a biasing force biasing the button 318 in a distal direction. The biasing force can be provided by a biasing element 250.

[0245] The blocking mechanism is configured to disengage the first element from the second element at the zero dose position where the set dose has been fully delivered, thereby allowing the dose delivery mechanism 354 to return to the dose set state, and thus set a subsequent dose after the previous medicine delivery is completed.

[0246] Illustratively, the first element rotates relative to the second element in a first direction during dose setting and in a second direction opposite the first direction during dose delivery. Relative movement between the first and second elements can place the first and second elements in relative positions that prevent mutual engagement at the end of dose delivery and / or when the dose is set.

[0247] In the second injection pen 300, the first element is configured as a circumferential rib 156 extending longitudinally around the axis of the housing 332, and the second element is configured as a stopper or counter element formed by the engagement feature 116 of the snap element 24 that moves along the circumferential rib 124 during delivery of the dose.

[0248] Illustratively, the second element passes through the first element upon release of the button 318 at the end of dose delivery. For example, the second element can pass through an opening in the first element. The second element can rotate to be aligned with the opening at the end of dose delivery.

[0249] Additionally or alternatively, the blocking mechanism may be configured to prevent the transition of the dose delivery mechanism 354 from the dose set state to the dose delivery state unless a dose has been set. Such a blocking mechanism is illustratively also implemented in the dose delivery mechanism 54 of the first injection pen 10. Illustratively, the second element passes through the first element upon transition of the dose delivery mechanism 54, 354 from the dose set state to the dose delivery state. Illustratively, the second element passes through one of the openings or notches 158 in the first element. Illustratively, the second element rotates to be aligned with the opening 158 when the dose has been set.

[0250] Illustratively, the second element passes through one of the openings or notches 158 in the first element when the mechanism transitions from the dose setting state to the dose delivery state. Such opening 158 prevents blocking and thus allows axial movement of the button 18, 318 to initiate dose delivery.

[0251] Illustratively, a first element of the blocking mechanism and one of the dose stopper 118 and the counter element 116, e.g. the dose stopper 118, are fixed to the same member of the dose delivery mechanism 54, 354. Furthermore, a second element of the blocking mechanism and the other of the dose stopper 118 and the counter element 116, e.g. the counter element 116, are fixed to the same further member of the dose delivery mechanism 54, 354. This allows for accurate alignment of the elements of the blocking mechanism and the dose defining mechanism 115, improving the reliability of the dose delivery mechanism 54, 354.

[0252] The member of the mechanism comprising the first element of the blocking mechanism and one of the dose stopper 118 and the counter-element 116 is exemplarily the dose selector 28 of the dose delivery mechanism 54, 354. The further member of the dose delivery mechanism 54, 354 comprising the second element of the blocking mechanism and the other of the dose stopper 118 and the counter-element 116 is exemplarily a carrier which is rotationally moveable relative to the dose selector 28. The carrier is exemplarily part of the dose metering member 23, 332, i.e. by means of the snap element 24 of the dose metering member 23, 323.

[0253] The dose selector 28 is illustratively disposed at least partially within the outer housing, i.e., housing 32, 332, of the dose delivery mechanism 54, 354. The dose selector 28 is illustratively configured to protrude from the outer housing.

[0254] Illustratively, one of the first and second elements of the blocking mechanism and one of the dose stopper 118 and the counter element 118 are formed by a single element. By way of example, the second element of the blocking mechanism and the counter element 116 of the dose defining mechanism 115 are formed by a single element. This facilitates alignment of the components of the blocking mechanism with the components of the dose defining mechanism 115.

[0255] The single element is illustratively a flexible element configured to snap onto the dose stopper 118 upon rotation relative to the dose stopper 118 .

[0256] In the first and second injection pens 10, 300, the dose delivery mechanism 54, 354 comprises a maximum dose mechanism for prohibiting further rotation of the dose setting element 22 upon rotation past the maximum dose setting, the maximum dose mechanism comprising a maximum dose stopper 126, illustratively formed by a hard stopper 128, and a blocking portion 124, illustratively formed by a hard stopper 124, configured to engage with the maximum dose stopper 126-128 upon rotation past the maximum dose setting. This provides a well-defined end of rotation position for the dose setting element 22. Furthermore, the maximum dose stopper 126-128 can absorb torque provided by the user and direct the torque to the housing 32, 332 of the dose delivery mechanism 54, 354.

[0257] The blocking portion 124 illustratively engages the maximum dose stop 126 128 just at the maximum dose setting. In other embodiments, the blocking portion 124 may engage the maximum dose stop 126 128 only after rotating past the maximum dose setting a predetermined amount.

[0258] The blocking portion 124 is illustratively configured as a hard stop that is rigidly connected, e.g., integrally formed, to a component of the mechanism. Similarly, the maximum dose stop 126 is illustratively configured as such a hard stop.

[0259] Illustratively, the maximum dose stop 126 126 and the blocking portion 124 are configured to rotate relative to one another during setting of a dose. As an example, one of the maximum dose stop 126 126 and the blocking portion 124, i.e. the maximum dose stop 126 126, may be rotationally fixed relative to the housing 32, 332 during setting of a dose, and the other of the maximum dose stop 126 126 and the blocking portion 124, e.g. the blocking portion 124, may be rotationally fixed relative to the dose setting element 22 during setting of a dose. The other of the maximum dose stop 126 126 and the blocking portion 124 may be rotationally movable relative to the dose setting element 22 during delivery of a dose.

[0260] Illustratively, the maximum dose stop 126 is configured as a radial stop, and the blocking portion 124 is configured to rotate relative to the maximum dose stop 126 when rotating past the maximum dose. Such a radial stop provides a well-defined rotational position at which the blocking portion 124 and the maximum dose stop 126 engage.

[0261] The maximum dose stop 126 and the blocking portion 124 illustratively include engagement surfaces that engage with one another. The engagement surfaces are illustratively oriented essentially perpendicular, i.e. normal, to a circumferential direction about a longitudinal axis of the dose delivery mechanism 54, 354.

[0262] Illustratively, one of the maximum dose stop 126 and the blocking portion 124, e.g., the maximum dose stop 126, is rotationally fixed relative to the housing 32, 332. Illustratively, one of the maximum dose stop 126 and the blocking portion 124 is permanently rotationally fixed relative to the housing 32, 332 during both dose setting and dose delivery.

[0263] Illustratively, one of the maximum dose stopper 126 and the blocking portion 124 is fixed to an outer housing portion of the dose delivery mechanism 54, 354. The outer housing portion is illustratively configured as a housing connector located between the dose setting element 22 and the housing 32, 332 of the injection pen 10, 300. The outer housing portion is configured as a dose selector 28.

[0264] Illustratively, the other of the maximum dose stop 126 and the blocking portion 124, e.g. the blocking portion 124, is rotationally fixed relative to the dose metering member 23, 332. Thus, the other of the maximum dose stop 126 and the blocking portion 124 rotates relative to the housing 332, 32 both during dose setting and dose delivery. This allows the maximum dose mechanism to be reset upon delivery of a dose. In embodiments in which the rotational position of the dose metering member 23, 332 defines a set dose, by rotationally fixing one of the maximum dose stop 126 and the blocking portion 124 to the dose metering member 23, 332, the maximum dose position at which the maximum dose stop 126 and the blocking portion 124 engage with each other is precisely defined.

[0265] Exemplarily, the other of the maximum dose stop 126 and the blocking part 124 is fixed to a coupling member which rotationally couples the dose metering member 23, 332 to the dose setting element during dose setting. The coupling member is formed by a snap element 24.

[0266] Illustratively, one of the dose stopper 118 and the counter element 116, e.g. the dose stopper 118, and one of the maximum dose stopper 126 and the blocking portion 124, e.g. the maximum dose stopper 126, are fixed to the same member of the dose delivery mechanism 54, 354. This allows the relative position of the components of the dose defining mechanism 115 to the components of the maximum dose mechanism to be precisely defined. The member of the dose delivery mechanism 54, 354 is illustratively the dose selector 28.

[0267] Illustratively, the other of the dose stopper 118 and the counter element 116, e.g. the counter element 116, and the other of the maximum dose stopper 126 and the blocking portion 124, e.g. the blocking portion 124, are fixed to the same further member of the dose delivery mechanism 54, 354. This again allows the relative position of the components of the dose defining mechanism 115 to the components of the maximum dose mechanism to be precisely defined. The further member may for example be a carrier which is rotationally movable with respect to the dose selector 28 and which is formed by the snap element 24.

[0268] Illustratively, the dose delivery mechanism 54, 354 of the first and second injection pens 10, 300 comprises a zero dose mechanism that prevents further axial movement of the nut 38 at the end of dose delivery, the zero dose mechanism comprising a zero dose stopper and a further blocking portion that is configured to engage with the zero dose stopper at the end of dose delivery. This provides a well-defined end position for the piston rod 44 at the end of dose delivery and thus contributes to accurately define the amount of medicament delivered.

[0269] In the first injection pen 10, the zero dose stop is formed by an end stop 176 of the guide 42 of the piston rod 44 and a further blocking part is formed by an end stop 174 of the driver 36. In the second injection pen 300, the zero dose stop is formed as a protrusion on the inner surface of the dose selector 28 and a further blocking part is formed by the hard stop 124 of the snap element 24.

[0270] The further blocking portion 124, 174 is illustratively configured as a hard stop that is rigidly connected, e.g., integrally formed, to a component of the dose delivery mechanism 54, 354. Similarly, the zero dose stopper 176 is illustratively configured as such a hard stopper.

[0271] Illustratively, the zero dose stopper 176 and the further blocking portion 124, 174 are configured to rotate relative to one another during delivery of a dose. For example, one of the zero dose stopper 176 and the further blocking portion 124, 174, e.g. the zero dose stopper 176, is rotationally fixed relative to the housing 32, 332 during setting of a dose, and the other of the zero dose stopper 176 and the further blocking portion 124, 174, e.g. the further blocking portion 124, 174, is rotationally fixed relative to the dose setting element 22 during setting of a dose. The other of the zero dose stopper 176 and the further blocking portion 124, 174, illustratively, is rotationally movable relative to the dose setting element 22 during delivery of a dose.

[0272] Illustratively, the zero dose stop 176 is configured as a radial stop and the further blocking portion 124, 174 is configured to rotate relative to the zero dose stop 176 at the end of delivery of the dose. Such a radial stop provides a well-defined rotational position at which the further blocking portion 124, 174 and the zero dose stop 176 engage.

[0273] The zero dose stopper 176 and the further blocking portion 124, 174 illustratively comprise engagement surfaces which engage with each other. The engagement surfaces may be oriented essentially perpendicular, e.g. vertically, to a circumferential direction about a longitudinal axis of the dose delivery mechanism 54, 354.

[0274] Illustratively, the zero dose stopper 176 and one of the further blocking parts 124, 174, e.g. the zero dose stopper 176, is rotationally fixed relative to the housing 32, 332. The zero dose stopper 176 and one of the further blocking parts 124, 174, illustratively, is permanently rotationally fixed relative to the housing 32, 332 both during dose setting and during dose delivery.

[0275] Illustratively, the zero dose stopper 176 and one of the further blocking portions 124, 174 are fixed to an outer housing portion of the dose delivery mechanism 54, 354. In the second injection pen 300, the outer housing portion is illustratively configured as a housing connector located between the dose setting element 22 and the housing 332 of the second injection pen 300. The first injection pen 10 may also be provided with such a zero dose stopper 176.

[0276] Illustratively, the other of the zero dose stopper 176 and the further blocking part 124, 174 is rotationally fixed relative to the dose metering member 23, 332. Thus, the other of the zero dose stopper 176 and the further blocking part 124 rotates relative to the housing 32, 332 both during dose setting and dose delivery. This allows the zero dose mechanism to be reset when a dose is set. In embodiments in which the rotational position of the dose metering member 23, 332 defines the set dose, by rotationally fixing one of the zero dose stopper 176 and the further blocking part 124, 174 to the dose metering member 23, 332, the zero dose position where the zero dose stopper and the further blocking part 124 engage with each other is precisely defined.

[0277] In the second injection pen 200 the zero dose stopper 176 and the other of the further blocking parts 124, 174 are fixed to a coupling member which rotationally couples the dose metering member 23, 332 to the dose setting member 22 during dose setting. The coupling member is formed by a snap element 24 of the dose metering member 323. The first injection pen 10 may also be provided with such an arrangement.

[0278] Exemplarily, one of the dose stopper 118 and the counter element 116 of the second injection pen 300, e.g. the dose stopper 118, and one of the zero dose stopper and the further blocking part 124 of the second injection pen 300, e.g. the zero dose stopper, are fixed to the same member of the dose delivery mechanism 354. This allows the relative position of the components of the dose defining mechanism 115 to the components of the zero dose mechanism to be precisely determined. The member of the dose delivery mechanism 354 is exemplarily the dose selector 28. The first injection pen 10 may also have such a configuration.

[0279] Illustratively, the other of the dose stopper 118 and the counter element 116 of the second injection pen 300, e.g. the counter element 116, and the other of the zero dose stopper and the further blocking part 124 of the second injection pen 300, e.g. the further blocking part 124, are fixed to the same further member of the dose delivery mechanism 354. This again allows the relative position of the components of the dose defining mechanism 115 to the components of the zero dose mechanism to be precisely defined. The further member may for example be a carrier which is rotationally movable with respect to the dose selector 28. The first injection pen 10 may also have such a configuration.

[0280] Illustratively, in the second injection pen 300, one of the maximum dose stopper 126 and the blocking portion 124 of the maximum dose mechanism and one of the zero dose stopper and the further blocking portion 124 of the zero dose mechanism, e.g. the maximum dose stopper 126 and the zero dose stopper, are fixed to the same member of the mechanism. Furthermore, the other of the maximum dose stopper 126 and the blocking portion 124 of the maximum dose mechanism and the other of the zero dose stopper and the further blocking portion 124 of the zero dose mechanism, e.g. the blocking portion 124 and the further blocking portion 124, are fixed to the same further member of the mechanism. This provides accurate alignment between the components of the maximum dose mechanism and the components of the zero dose mechanism. The first injection pen 10 may also have such a configuration.

[0281] Regardless of whether they are fixed to the same member of the mechanism, the maximum dose stop 126 and / or the minimum dose stop may be integrally formed with the member to which they are fixed. Similarly, the blocking portion 124 and / or the further blocking portion 124 may be integrally formed with the member to which they are fixed.

[0282] Illustratively, in the second pen 300, the blocking portion 124 of the maximum dose mechanism forms a further blocking portion 124 of the minimum dose mechanism, which allows to precisely define the distance between the maximum dose position and the zero dose position. The first injection pen 10 may also have such a configuration.

[0283] In general, the dose delivery mechanism 54, 354, 554, 754 may comprise a clutch mechanism 113 having a first engagement portion and a second engagement portion, the clutch mechanism 113 being closed during one of dose setting and dose delivery and open during the other of dose setting and dose delivery. The clutch mechanism 113 is in an open state when the first engagement portion and the second engagement portion are not engaged with each other, and the clutch mechanism 113 is in a closed state when the first engagement portion and the second engagement portion are engaged with each other.

[0284] Illustratively, the first and second injection pen dose delivery mechanisms 54, 354 include a clutch mechanism 113 that rotationally locks the nut 38 to the piston rod 44 during dose delivery and rotatably releases the nut 38 from the piston rod 44 during dose setting. By rotationally locking the nut 38 to the piston rod 44, the clutch mechanism 113 forces simultaneous proximal movement of the nut 38 and the piston rod 44. Illustratively, the clutch mechanism 113 rotationally locks a threaded connection 189 that couples the nut 38 to the piston rod 44. The clutch mechanism 113 locks the nut 38 to the piston rod 44 in a closed state and rotatably releases the nut 38 from the piston rod 44 in an open state.

[0285] The clutch mechanism 113 illustratively comprises a first engagement portion and a second engagement portion configured to engage with one another to rotationally lock the nut 38 to the piston rod 44. The first engagement portion and the second engagement portion are illustratively configured to disengage from one another by relative axial movement with respect to one another. The first engagement portion is illustratively formed by teeth 114 of the connector 26, and the second engagement portion is illustratively formed by teeth 108 of the dose setting element 22.

[0286] The clutch mechanism 113 is illustratively configured to transition from an open state to a closed state when the button 18, 318 moves and the dose delivery mechanism 54, 354 transitions from a dose setting state to a dose delivery state. One of the first and second engagement portions, e.g. the second engagement portion, is axially fixed to the button 18, 318 and the other of the first and second engagement portions, e.g. the first engagement portion, is axially fixed to the housing 32, 332. Additionally or alternatively, the first engagement portion is axially fixed to the dose metering member 23, 332.

[0287] Illustratively, the first engagement portion is rotationally fixed to the housing 32 , 332 and the second engagement portion is rotationally fixed to the nut 38 .

[0288] The second engagement portion is illustratively rotationally fixed to the button 18, 318 and / or the dose setting element 22.

[0289] Illustratively, the clutch mechanism 113 rotationally secures the nut 38 to the piston rod 44 via the housing 32, 332, e.g. via the dose setting element 22 and / or the button 18, 318, during delivery of a dose.

[0290] Illustratively, the clutch mechanism 113 acts between the button 1,318 and the housing 32,332 and / or between the dose setting element 22 and the housing 32,332.

[0291] Illustratively, the button 18, 318 is rotationally coupled, e.g., permanently rotationally coupled, to one of the first and second engagement portions. As an example, the button 18, 318 constitutes one of the first and second engagement portions.

[0292] Illustratively, the dose delivery mechanism 54, 354 comprises a further clutch mechanism 107, which rotationally locks the dose setting element 22 to one end of the spring 40 during setting of the dose and decouples the dose setting element 22 from one end of the spring 40 during delivery of the dose. Furthermore, the further clutch mechanism 107 has a further first engagement portion and a further second engagement portion, which is configured to move into engagement with the further second engagement portion to rotationally lock the dose setting element 22 to one end of the spring 40. The further clutch mechanism 107 allows tensioning of the spring 40 during setting of the dose and at the same time prevents the dose setting element 22 from rotating during delivery of the dose when the spring 40 is released again. The further first engagement portion is illustratively formed by a tooth 110 of the snap element 23 and the further second engagement portion is illustratively formed by a tooth 108 of the button 22.

[0293] The further clutch mechanism 107 illustratively transitions from a closed state, in which the further first engagement portion and the further second engagement portion are engaged, to an open state, in which the further first engagement portion and the further second engagement portion are disengaged, by movement of the button 18, 318. Movement of the button 18, 318 illustratively transitions the dose delivery mechanism 54, 354 from a dose setting state to a dose delivery state.

[0294] Illustratively, one of the further first engagement portion and the further second engagement portion, e.g. the further second engagement portion, is rotationally and axially fixed to the dose setting element 22. This allows the further clutch mechanism 107 to be opened or closed by relative movement of the dose setting element 22 with respect to the other of the further first engagement portion and the further second engagement portion.

[0295] Illustratively, one of the further first engagement portion and the further second engagement portion is rotationally and axially fixed to the button 18, 318. This results in the dose setting element 22 being at least rotationally fixed to the button 18, 318.

[0296] Illustratively, a further clutch mechanism 107 acts between the dose metering member 23, 332 and the dose setting element 22. The dose metering member 23, 332 can then rotationally couple the dose setting element 22 to one end of the spring 40.

[0297] Illustratively, one of the further first engagement portion and the further second engagement portion, e.g. the further first engagement portion, is rotationally fixed to the dose metering member 23, 332. Illustratively, one of the further first engagement portion and the further second engagement portion may be axially fixed to the dose metering member 23, 332.

[0298] Illustratively, the clutch mechanism 113 comprises a first engagement portion which engages with a second engagement portion to rotationally secure the nut 38 to the piston rod 44 upon delivery of a dose, and a further second engagement portion of the further clutch mechanism 107 forms the first engagement portion of the clutch mechanism 113. This provides a compact construction of the clutch mechanisms 107, 113.

[0299] The nut 38 is illustratively rotationally fixed relative to the button 18, 318 and / or the dose setting element 22. By way of example, the nut 38 is rotationally fixed relative to the button 18, 318 and / or the dose setting element 22 and axially movable. The nut 38 is coupled to the button 18, 318 and / or the dose setting element 22 by a rotation lock. The rotation lock is formed by the nut 38 and one of the button 18, 318 and the dose setting element 22, for example by the nut 38 and the button 18, 318.

[0300] The nut 38 is rotationally moveable relative to the piston rod 44 when the dose delivery mechanism 54, 354 is in a dose setting state and the nut 38 is rotationally fixed relative to the piston rod 44 when the dose delivery mechanism 54, 354 is in a dose delivery state. Rotation of the nut 38 relative to the piston rod 44 during dose setting results in axial movement due to the threaded connection between the nut 38 and the piston rod 44. By rotationally locking the nut 38 to the piston rod 44 during dose delivery, the threaded connection between the nut 38 and the piston rod 44 is prevented and the nut 38 and the piston rod 44 are axially fixed relative to each other.

[0301] The nut 38 is rotated by the dose setting element 22 during setting of a dose and performs an axial movement due to its threaded connection to the piston rod 44. Rotation of the nut 38 causes it to translate axially distally along a thread located on the piston rod 44 during setting of a dose and to translate proximally during cancellation of a dose. The axial movement of the nut 38 relative to the piston rod 44 determines the axial movement of the piston rod 44 during delivery of a dose and thus the amount of medicine expelled in the delivery of a dose. Some general notes regarding this disclosure:

[0302] The second threaded connection 170, 172 may be provided between the driver 36 and the piston rod guide 42. However, there are several other options as to where the second threaded connection 170, 172 may be provided. For example, the second threaded connection may be provided between the dose metering element 34 and the housing 32. The second threaded connection 170, 172 preferably acts between any part that is rigidly connected to the driver 36 and any part that is rigidly connected to the housing 32.

[0303] Preferably, the actuating members 18, 20, 22 are coupled to the piston rod 44 via the nut 38 in such a way that axial movement of the actuating members 18, 20, 22 during dose delivery causes axial movement of the nut 38 and the piston rod 44. The nut 38 forms a first threaded connection with the piston rod 44 via external threads 190 that mate with internal threads 192 to apply an axial force from the nut 38 to the piston rod 44 to move the piston rod 44 axially through the nut 38 during dose delivery. Relative rotational movement of the nut 38 and the piston rod 44 is prevented during dose delivery, such that axial movement of the nut 38 causes axial movement of the piston rod 44.

[0304] With regard to the optional feature that "all parts configured to rotate relative to the housing 32 during dose delivery are connected to the housing 32 via exactly one threaded connection 170, 172", it is pointed out that the dose delivery mechanism 54 may comprise the driver 36, the dose sleeve 34, and / or the snap element 24. One or more of these parts may be configured to rotate relative to the housing 32 during dose delivery. Furthermore, the delivery mechanism 54 may have one or more further parts configured to rotate relative to the housing 32 during dose delivery. All parts of the delivery mechanism 54 configured to rotate relative to the housing 32 during dose delivery may form a subassembly. This subassembly may form exactly one threaded connection 170, 172 with the housing 32 or any part rigidly connected to the housing 32.

[0305] The coupling means 100, 102 can be formed on the injection button and the snap element 24. However, the coupling means 100 may alternatively be formed on the snap ring 20 or the dose setting knob 22. The coupling means 102 can generally be formed on any part that cannot move axially relative to the housing. A person skilled in the art will appreciate that there are multiple options for where to place the coupling means 100, 102. If the coupling means 100, 102 are configured to permanently axially lock the dose setting knob 22 to the dose setting device or the housing 50, this can be done in multiple ways, such as a permanent form-fit connection or a permanent friction-fit connection.

[0306] In general, the dose setting mechanism may comprise a clutch connecting a nut 38 to the piston rod 44, where the nut 38 is rotationally fixed to the piston rod 44 during delivery and rotates relative to the piston rod 44 during setting of a dose. Preferably, when setting a dose, rotation of the dose setting knob rotates the nut 38 relative to the piston rod 44. There are several ways how the connection between the dose setting knob and the nut 38 can be designed.

[0307] Generally, the piston rod 44 may be rotationally fixed relative to the housing during dose delivery / dispatch.

[0308] The proximal end 14 includes a delivery outlet. The distal end 12 is disposed at an opposite end to the proximal end 14. The delivery outlet can include one of a needle, a cannula, and a connection point for a needle or a cannula.

[0309] The cover 16 may cover a portion of a dose delivery actuation mechanism configured to actuate the delivery of a dose. The dose delivery actuation mechanism is a component configured to enable the delivery of a dose from the delivery device. The actuation mechanism may comprise an injection button 18 that forms the distal end face of the injection pen. The cover 16 may also cover a dose setting knob 22. In this way, the cover 16 prevents setting of a dose and / or actuation of an injection before mixing of the two components has taken place.

[0310] The as-delivered state is a state in which all parts of the dose delivery mechanism 54 are disposed in the same relative position relative to one another as they were after manufacture of the dose delivery mechanism 54. In other words, the as-delivered state is a state in which the user has not rotated or otherwise changed the position of the dose setting member 34 relative to the housing. Thus, when a dose is set by the user, the dose delivery mechanism 54 is no longer in the "as-delivered state" but instead in the "set state". According to one embodiment, in the "as-delivered state", the dose setting knob 22 cannot be rotated towards the zero dose position. According to one embodiment, actuation is prevented in the "as-delivered state" to prevent accidental actuation.

[0311] The dose delivery mechanism may comprise an actuating member 18, a dose setting knob 22, a snap element 24, a dose selector 28, and / or a clip 30. The actuating member 18 may be configured to be pressed by a user to initiate the injection process. The snap element 24 is preferably configured to engage the dose selector 28, preferably at different rotational positions, to define settable doses. The clip 30 may be used in combination with the knob cover 16 to avoid movement of the actuating member 18 relative to the housing 32 when the pen is dropped from the proximal end 14. [Explanation of symbols]

[0312] 1 Proximal 10 Injection pen 12 Distal end 14 Proximal end 16 Knob cover 16a Closed perimeter 16b Closed Surface 18 Injection button / adjustment element 18a Cylindrical part 19 Outer Rim 20 Snap ring / connector 22 Dose setting knob / dose setting element 23 Dose metering elements 24 Snap Elements 26 Connectors 28 Sleeve / Dose Selector 30 Knob Key 32 Housing 32a surface 34 Dose setting sleeve / dose metering element 36 Drivers 38 Nut 40 Spring 42 Piston rod guide 43 Connector 44 Piston rod 45 Distal part 46 Piston disc / bearing 48 Cartridge 50 Cartridge container / Medicine container 52 Cartridge key / cartridge holder 54 Dose Delivery Mechanism 56 Drug Reconstitution Unit 58 Wing 60 Rug 62 Windows 64 Ridge 66 Contact part 66a front 68 Notch 69 Chamfered part 70 Axial abutment ridge 72 Gap 74 Linear recess 76 Anti-rolling measures 78 Anti-rolling measures 80 front 81 Axial Lock 82 Axial fixing means 84 Ribs 86 Axial fixing means 88 Undercut 89 Rotation Lock 90 Rotation Fixing Means 92 Rotational Fixation Means 93 Toothed part 94 Rotational Fixation Means 96 Rotational Fixation Means 97 Latch mechanism 98 Assembly Method 98a Latch part 98b Further latch parts 100 Coupling means 100a Chamfered surface 101 Notch 102 Coupling means / latch counterpart 104 Ribs 106 Groove 107 Clutch mechanism 108 teeth 110 teeth 112 Bonding surface 114 teeth 115 Dose Definition Mechanism 116 Engagement mechanism 118 Dose Stopper 118a Dose stopper 118b Dose stopper 118c Dose stopper 118d Dose stopper 120 Elastically deformable parts 121 Cutout 122a-d side 123a-d side 124 Hard Stopper 126 Hard Stopper 128 Hard Stopper 130 Opening 132 Slots 134 Ribs 136 Protrusion 136a Chamfered surface 138 Ribs 140 Groove 142 Axial fixing means 144 Intake 146 Axial fixing means 148 Rotational Fixation Means 150 Rotation fixing means 152 Rotational Fixation Means 154 Rotational Fixation Means 156 Rib 158a Notch 158b Notch 158c Notch 158d Cutout 160 Proximal edge 162 Distal edge 164 Retaining protrusion 166 Windows 168a Label 168b Label 168c Label 168d Label 168e Label 169a Non-circular outer surface 169b Non-circular inner surface 170 Male thread 171 Fixed part 172 Female thread 173 Face 174 End stopper 176 End stopper 177 Attachment means 178 Axial fixing means 179 Attachment means 180 Axial fixing means 182 Rotational Fixation Means 184 Rotational Fixation Means 186 Opening 188 Section 189 Threaded Connections 190 Male thread 192 Female thread 194 Pushing surface 196 Front 198 Coupling means 200 Coupling means 202 First Chamber 204 Second Chamber 206 Bypass 208 First sealing element 210 Second sealing element / plunger 212 Axial fixing means 214 Axial fixing means 216 Rotational Fixation Means 218 Rotational Fixation Means 220 Window 221 Notch 222 Window 223 Slots 224 thread 226 End face 228 Surface 230 1st thread 232 Second Thread 234 Snap Elements 236 Opening 238 Opening 240 Opening 242 Displacement 244 Radial end stopper 246 Exterior 248 Interior Space 249 Holding part 250 energizing element 252 Opening 254 Inside 256 Exterior 258 Annular Space 260 Inner surface 262 Outer surface 264 Outer surface 266 End face 268 End face 300 Drug delivery device 301 Cap 305 Container Holder 306 Needle Connector 307 Connector 318 Adjustment Factors 323 Dose metering elements 332 Housing 333 Upper housing part 334 Dose metering element 335 Threaded Connection 336 Driver 337 Further screw connections 342 Piston rod guide 343 Connector 348 Pharmaceutical containers 349 Needle end 354 Dose Delivery Mechanism 500 Drug delivery device 501 Needle Assembly 502 Cannula 503 Needle Cap 504 Cap 505 Container Holder 506 Connector 507 Clutch 508 First clutch part 509 Second clutch part 513 Clutch mechanism 514 teeth 515 teeth 518 Adjustment Factor 520 Joint Element 523 Dose Metering Elements 524 Connecting members 525 Extension 527 Connector 528 Sleeve 528a outer part 529 Latch Counterpart 530 More Latch Counterparts 532 Housing 533 Retaining Lug 534 Housing Window 535 Opening 543 Connector 554 Dose Delivery Mechanism 560 Rotatable fixed part 561 Annular Rim 562 thread 563 Rotation Fixed 564 Longitudinal Ridge 566 Rug 567 Opening 568 Radial Stopper 569 Stopper surface 570 Rotatable Fixture 571 Annular Rim 573 Opening 575 Ridge 580 End Plate 582 Bar 584 Axial fixed 585 Rotation Fixed 586 Recess 587 Clicka 590 Recess 592 Rims 597 Latch mechanism 599 Further latching mechanisms 600 Latch part 610 Windows 612 Thread 614 Opening 616 Ridge 618 Recess 620 Connector 622 Rug 624 Recess 626 Annular Rim 630 Rug 632 Ridge 634 Proximal Blocking Element 635 Distal Blocking Element 636 Stopper surface 700 Drug delivery device 720 Joint Element 754 Dose Delivery Mechanism L1 Length L2 Length W1 width W2 Width

[0313] Additionally, the present disclosure relates to the following first set of enumerated embodiments:

[0314] EMBODIMENT 1 A dose setting mechanism (54) configured to set a desired dose for an injection device (10), the dose setting mechanism (54) comprising a housing (32), a dose setting knob (18, 22) and a dose setting device (24); the dose setting knob (22) is configured to set a desired dose by a combined axial and rotational movement by forced guidance of the dose setting knob (22) relative to the housing (32); The dose setting mechanism (54) comprises one or more coupling means (100), and during drug delivery, the dose setting knob (18, 22) moves axially relative to the dose setting device (24) and / or the housing (32), and the one or more coupling means (100) are configured to engage with at least one of the dose setting device (24) and the housing (32) to permanently axially lock the dose setting knob (18, 22) to the respective one of the dose setting device (24) and the housing (32).

[0315] EMBODIMENT 2 the dose setting mechanism is configured to set a desired dose for the one-time use injection device that is inoperable when the dose setting knob is axially locked to a respective one of the dose setting device and the housing; A dose setting mechanism according to embodiment 1.

[0316] EMBODIMENT 3 A dose setting mechanism (54) according to embodiment 1 or 2, wherein the dose setting knob (18, 22) is non-rotatable relative to the dose setting device (24) and / or the housing (32) when the dose setting knob (18, 22) is axially locked to a corresponding one of the dose setting device (24) and the housing (32).

[0317] EMBODIMENT 4 the one or more coupling means (100) being configured to cooperate between a dose setting device (24) and a dose setting knob (18, 22); A dose setting mechanism according to any one of embodiments 1 to 3.

[0318] EMBODIMENT 5 the dose setting knob (18, 22) comprises one or more coupling means (100) configured to cooperate with a respective one of the dose setting device (24) and the housing (32); A dose setting mechanism (54) according to any one of embodiments 1 to 4.

[0319] EMBODIMENT 6 One or more coupling means (100) are arranged on the outer circumferential surface of the dose setting knob (18, 22) and corresponding coupling means (102), e.g. a circumferentially extending ledge, are arranged on the inner circumferential surface of the dose setting device (24). A dose setting mechanism (54) according to any one of embodiments 1 to 5.

[0320] EMBODIMENT 7 The one or more fastening means (100) comprise one or more snap elements, in particular one or more elastically deformable tongues; A dose setting mechanism (54) according to any one of embodiments 1 to 6.

[0321] EMBODIMENT 8 one or more snap elements have a chamfered surface configured to engage the protrusion (102), in particular a circumferentially extending ledge, to elastically deform the snap element; A dose setting mechanism according to embodiment 7.

[0322] EMBODIMENT 9 a notch (101) is provided adjacent to at least one of the one or more coupling means (100); A dose setting mechanism (54) according to any one of embodiments 1 to 8.

[0323] EMBODIMENT 10 the notch (101) is provided partially surrounding at least one of the one or more coupling means (100); A dose setting mechanism according to embodiment 9.

[0324] EMBODIMENT 11 the dose setting device (24) comprises one or more protrusions (116) for setting said desired dose in cooperation with a dose selector (28); A dose setting mechanism (54) according to any one of embodiments 1 to 10.

[0325] EMBODIMENT 12 the dose setting knob (18, 22) is coupled to the dose selector (28) in a rotationally fixed manner during drug delivery, and / or the dose setting knob (18, 22) rotates relative to the housing (32) while the dose selector (28) does not rotate relative to the housing (32) during dose setting; A dose setting mechanism according to any one of embodiments 1 to 11.

[0326] EMBODIMENT 13 the dose setting knob (18, 22) defines an end surface for manually pushing the dose setting knob (18, 22) axially relative to the dose setting device (24) and / or the housing (32) during delivery of the medication; A dose setting mechanism (54) according to any one of embodiments 1 to 12.

[0327] EMBODIMENT 14 the dose setting knob (18, 22) and the dose setting device (24) are axially movable relative to one another for setting a dose by rotating the dose setting knob (18, 22) relative to the housing (32); A dose setting mechanism according to any one of embodiments 1 to 13.

[0328] EMBODIMENT 15 the dose setting device (24) and the dose setting knob (18, 22) are rotationally fixed relative to one another during setting of a dose, and / or the dose setting device (24) and the dose setting knob (18, 22) rotate relative to one another during delivery of the drug; A dose setting mechanism according to any one of embodiments 1 to 14.

[0329] EMBODIMENT 16 the dose setting device (24) rotates relative to the housing (32) during delivery of the medication, and / or the dose setting knob (18, 22) does not rotate relative to the housing (32) during delivery of the medication; A dose setting mechanism (54) according to any one of embodiments 1 to 15.

[0330] EMBODIMENT 17 The dose setting knob (18, 22) and the dose setting device (24) are axially movable relative to the housing (32) in setting the dose. A dose setting mechanism according to any one of embodiments 1 to 16.

[0331] EMBODIMENT 18 The dose setting knob (18, 22) and the dose setting device (24) are configured not to move relative to each other when setting a dose; A dose setting mechanism according to any one of embodiments 1 to 17.

[0332] EMBODIMENT 19 the dose setting knob (18, 22) comprises an injection button (18), and said one or more coupling means (100) are configured to permanently axially lock said injection button (18) to a respective one of the dose setting device (24) and the housing (32); A dose setting mechanism (54) according to any one of embodiments 1 to 18.

[0333] EMBODIMENT 20 At least a portion of the dose setting knob (18, 22) moves axially upon delivery of the dose. A dose setting mechanism according to any one of embodiments 1 to 19.

[0334] EMBODIMENT 21 The dose setting knob (18, 22) includes an injection button (18) that moves axially upon delivery of a dose. A dose setting mechanism according to any one of embodiments 1 to 20.

[0335] EMBODIMENT 22 During delivery of the drug, the dose setting knob (18, 22) moves axially relative to the dose setting device (24), and the one or more coupling means (100) are configured to engage with the dose setting device (24) to permanently axially lock the dose setting knob (18, 22) to the dose setting device (24) upon relative movement between the dose setting knob (18, 22) and the dose setting device (24). A dose setting mechanism according to any one of embodiments 1 to 21.

[0336] EMBODIMENT 23 A medicine delivery device (10), in particular an injection device, comprising a dose setting mechanism (54) according to any one of the embodiments 1 to 22.

[0337] EMBODIMENT 24 A single-use, single-dose pen, in which one or more doses can be selected for a single use by a dose setting mechanism (54) according to any one of embodiments 1 to 22.

[0338] EMBODIMENT 25 A method for locking a medication delivery device (10), particularly an injection pen (10), after first use, comprising: setting a dose by a combined axial and rotational movement of the dose setting knob (18, 22) with forced guidance relative to the housing (32); axially moving the dose setting knob (18, 22) of the dose setting mechanism (54) relative to the dose setting device (24) and / or the housing (32) to actuate one or more coupling means (100) to permanently axially lock the dose setting knob (18, 22); The method includes:

[0339] EMBODIMENT 26 moving said dose setting knob (18, 22) of the dose setting mechanism (54) axially relative to the dose setting device (24) and / or the housing (32) to engage one or more coupling means (100) of the dose setting knob (18, 22) with the dose setting device (24) or the housing (32) to axially lock the dose setting knob (18, 22) to the dose setting device (24) and / or the housing (32). A method for locking a medication delivery device (10), in particular an injection pen (10), according to embodiment 25, comprising:

[0340] EMBODIMENT 27 At least a portion of the dose setting knob (18, 22) moves axially upon delivery of the dose. 27. A method for locking an injection pen according to embodiment 25 or 26.

[0341] EMBODIMENT 28 The dose setting knob (18, 22) includes an injection button (18) that moves axially upon delivery of a dose. A method for locking an injection pen according to any one of embodiments 25 to 27.

[0342] EMBODIMENT 29 Axial movement of the dose setting knob (18, 22) of the dose setting mechanism (54) relative to the dose setting device (24) and / or the housing (32) is accomplished by manually pushing the dose setting knob (18, 22) axially. A method for locking an injection pen according to any one of embodiments 25 to 28.

[0343] EMBODIMENT 30 the dose setting knob (18, 22) is moved axially backwards relative to the housing (32) to set a desired dose for the medicine delivery device, in particular the injection device (10), before moving the dose setting knob (18, 22) of the dose setting mechanism (54) axially forwards relative to the dose setting device (24) and / or the housing (32); A method for locking an injection pen according to any one of embodiments 25 to 29.

[0344] EMBODIMENT 31 The dose setting knob (18, 22) is moved axially rearwardly relative to the housing (32) by rotating the dose setting knob (18, 22) relative to the housing; A method for locking an injection pen according to any one of embodiments 25 to 30.

[0345] Additionally, the present disclosure relates to the following second set of enumerated embodiments:

[0346] EMBODIMENT 1 A set comprising a medicine delivery device (10) and a cover (16), the medication delivery device (10) having a dose delivery actuation mechanism (54) configured to adjust the medication delivery device (10) from an inactivated state to an activated state capable of delivering a dose; a cover (16) that is mechanically attached to the medication delivery device (10) prior to use of the medication delivery device (10), the cover (16) being configured to cover at least a portion of the dose delivery actuation mechanism (54) to prevent a user from prematurely activating the medication delivery device (10); The cover (16) is configured to be movable in a distal direction to expose the portion of the dose delivery actuation mechanism (54) for actuating the medication delivery device (10) during use of the medication delivery device (10).

[0347] EMBODIMENT 2 The cover (16) is removable from the medication delivery device (10). A set according to embodiment 1.

[0348] EMBODIMENT 3 the medication delivery device (10) and the cover (16) include form-fit engagement means (58, 228) that are used to releasably attach the cover (16) to the medication delivery device (10) prior to use of the medication delivery device (10); A set according to embodiment 1 or 2.

[0349] EMBODIMENT 4 The form-fit engagement means (58, 228) comprises one or more snap-fit ​​connections; A set according to embodiment 3.

[0350] EMBODIMENT 5 A set according to embodiment 3 or 4, wherein the form-fitting engagement means (58, 228) comprises one or more wings (58) that can be deflected outward, in particular radially, with respect to a longitudinal axis extending through the medication delivery device (10).

[0351] EMBODIMENT 6 A set according to any one of embodiments 3 to 5, wherein the form-fitting engagement means comprises one or more lugs, in particular a lug having a triangular outer cross-section in at least one of its planes.

[0352] EMBODIMENT 7 A set according to embodiment 6, wherein the one or more lugs are positioned immediately adjacent to the window of the cover.

[0353] EMBODIMENT 8 A set according to embodiment 7, wherein the abutment portion is arranged on an opposite side of the window relative to the lug.

[0354] EMBODIMENT 9 The set according to embodiment 8, wherein the abutment portion is configured to contact a housing of the medication delivery device.

[0355] EMBODIMENT 10 10. The set according to embodiment 8 or 9, wherein the abutment portion is configured to contact a notch in the medication delivery device.

[0356] EMBODIMENT 11 A set according to embodiments 6 to 10, wherein the lugs are arranged at the proximal ends of the wings, in particular one lug per wing.

[0357] EMBODIMENT 12 A removal means (242) is provided for removing the cover (16) from the medication delivery device (10), and preferably the removal means (242) engages the wings (58), particularly the lugs, to deflect the wings (58) outwardly for removal of the cover (16). A set according to any one of embodiments 1 to 11.

[0358] EMBODIMENT 13 a detachment element (50) attachable to or pre-attached to the medication delivery device (10); The removal element (50) comprises a removal means (242), A set according to embodiment 12.

[0359] EMBODIMENT 14 The removal element (50) is a cartridge container. A set according to embodiment 13.

[0360] EMBODIMENT 15 The cartridge container (50) is configured to be attached, in particular screwed, to the medicine delivery device (10), in particular to the housing (32, 42) of the medicine delivery device (10), and the removal means (242) is configured to remove the cover (16) from the medicine delivery device (10) during or after the attachment, in particular screwing, of the cartridge container (50) to the medicine delivery device (10). A set according to embodiment 14.

[0361] EMBODIMENT 16 The dose delivery actuation mechanism (54) comprises a dose setting assembly for manually setting a dose; A set according to any one of embodiments 1 to 15.

[0362] EMBODIMENT 17 The dose setting assembly comprises a knob (22) which is rotated to set the dose, preferably The knob (22) is rotatable in one direction to increase the dose and in the opposite direction to decrease the dose. A set according to any one of embodiments 1 to 16.

[0363] EMBODIMENT 18 The cover (16) is rotationally and / or axially constrained relative to the medication delivery device (10) in the assembled state of the set. A set according to any one of embodiments 1 to 17.

[0364] EMBODIMENT 19 the housing of the medication delivery device has a chamfered portion, in particular a notch is provided in the chamfered portion, and the cover is provided with a complementary shaped collar that abuts the chamfered portion; A set according to any one of embodiments 1 to 18.

[0365] EMBODIMENT 20 A set according to any one of embodiments 1 to 19, wherein a distal end of the cover, particularly remote from the wing, is one of open and closed.

[0366] EMBODIMENT 21 A set according to any one of embodiments 1 to 20, wherein the inner shape of the cover (16) is complementarily shaped to the outer shape of at least a portion of the housing of the medicine delivery device (10) that contains the dose delivery actuation mechanism (54).

[0367] EMBODIMENT 22 The medication delivery device (10) is part of a pen-type injection device (10). A set according to any one of embodiments 1 to 21.

[0368] EMBODIMENT 23 The medication delivery device comprises a snap element and a dose selector which are rotated relative to one another to set a dose. A set according to any one of embodiments 1 to 22.

[0369] EMBODIMENT 24 The medication delivery device includes a nut having an internal thread and a piston rod having an external thread that mates with the internal thread of the nut. A set according to any one of embodiments 1 to 23.

[0370] EMBODIMENT 25 the cover having the form of a sleeve axially mounted on the medication delivery device; A set according to any one of embodiments 1 to 24.

[0371] EMBODIMENT 26 the cover is attached to the medication delivery device from a distal end of the medication delivery device; A set according to any one of embodiments 1 to 25.

[0372] EMBODIMENT 27 the cover (16) is configured to cover at least a portion of the dose delivery actuation mechanism (54) so ​​as to prevent a user from activating the medicament delivery device (10), in particular from setting a dose, prior to preparation of the medicament in the receptacle cartridge (48), in particular prior to mixing of two or more components of the medicament in the receptacle cartridge (48); A set according to any one of embodiments 1 to 26.

[0373] EMBODIMENT 28 The reservoir cartridge is configured to dispense the medicament while the reservoir cartridge is attached, in particular screwed, to the medicine delivery device. A set according to embodiment 27.

[0374] EMBODIMENT 29 A cover for a medication delivery device, the cover configured to be mechanically attached to the medication delivery device to cover at least a portion of a dose setting assembly of the medication delivery device so as to prevent a user from prematurely setting a dose on the medication delivery device.

[0375] EMBODIMENT 30 1. A method for avoiding premature dosing in a medication delivery device (10), comprising: Attaching a cover (16) to the medication delivery device (10) to cover a dose delivery actuation mechanism (54) of the medication delivery device (10) to prevent a user from prematurely setting a dose prior to use of the medication delivery device (10). wherein the cover (16) is movable in a distal direction to expose a dose delivery actuation mechanism (54) for actuating the medication delivery device (10) during use of the medication delivery device (10).

[0376] EMBODIMENT 31 The cover is removed from the medication delivery device prior to use of the medication delivery device, preferably after a medication preparation step has been performed. A method according to embodiment 30.

[0377] EMBODIMENT 32 The cover is removed by a removal means provided on a cartridge container attached to the medicine delivery device. The method according to embodiment 31.

[0378] EMBODIMENT 33 The cover is removed from the medication delivery device by breaking a snap-fit ​​connection between the cover and the medication delivery device. The method according to embodiment 31 or 32.

[0379] EMBODIMENT 34 The drug delivery device comprises: A) setting a dose with a dose setting assembly; and B) Injecting a set dose. Used by The method according to any one of embodiments 30 to 33.

[0380] Additionally, the present disclosure relates to the following third set of enumerated embodiments:

[0381] EMBODIMENT 1 A housing (32); a piston rod (44) configured to move axially relative to the housing (32) to act on a plunger (46) that seals the fluid compartment (48) and to deliver a set dose; a dose setting member (34) movable relative to a piston rod (44); It is equipped with the position of the dose setting member (34) relative to the housing (32) defines the set dose; In the as-delivered state, the dose setting member (34) is pre-set to a position corresponding to a set dose greater than zero, the dose delivery mechanism (54).

[0382] EMBODIMENT 2 In the as-delivered state, the position of the dose setting member (34) corresponds to a dose between zero dose and a minimum dose that can be delivered by the dose delivery mechanism (54), e.g., a minimum dose per treatment for the purpose of the dose delivery mechanism. A dose delivery mechanism (54) according to embodiment 1.

[0383] EMBODIMENT 3 A dose delivery mechanism (54) according to embodiment 1 or 2, further comprising a dose indicating member (34), the dose indicating member (34) indicating a set dose depending on the rotational position of the dose indicating member (34) relative to the housing (32).

[0384] EMBODIMENT 4 The dose setting member (34) is configured as a dose display member (34); A dose delivery mechanism (54) according to embodiment 3.

[0385] EMBODIMENT 5 In the as-delivered state, the dose indicating member (34) indicates a set dose as different from a zero dose. A dose delivery mechanism (54) according to embodiment 3 or 4.

[0386] EMBODIMENT 6 the dose indicating member (34) in the as-delivered state indicates the set dose to be between zero dose and the minimum dose that can be delivered by the dose delivery mechanism, e.g. the minimum dose per treatment for which the dose delivery mechanism is intended; A dose delivery mechanism according to embodiment 5.

[0387] EMBODIMENT 7 The dose setting member (34) is configured to move, e.g. rotate, relative to the housing (32) to set a dose different from the pre-set dose, e.g. the dose provided by the therapy or one of the doses provided by the therapy. A dose delivery mechanism (54) according to any one of embodiments 1 to 6.

[0388] EMBODIMENT 8 the dose setting member (34) cannot be moved, e.g. rotated, directly from a preset position to the zero dose position; A dose delivery mechanism (54) according to embodiment 7.

[0389] EMBODIMENT 9 two parts arranged inside the housing of the dose delivery mechanism are configured to cooperate with each other to prevent movement, e.g. rotation, of a first one of the two parts relative to a second one of the two parts to prevent the dose setting member from moving directly from a preset position to a zero dose position, A dose delivery mechanism according to embodiment 8.

[0390] EMBODIMENT 10 Each of the two parts forms a hard stop; the two hard stops are configured to cooperate with each other to prevent movement, e.g. rotation, of a first of the two parts relative to a second of the two parts in order to prevent movement of the dose setting member from a preset position to a zero dose position, A dose delivery mechanism according to embodiment 9.

[0391] EMBODIMENT 11 the two hard stops are configured to move out of alignment upon delivery of a set dose, such as a therapeutic dose, such that the two hard stops are movable, e.g., rotatable, past one another during delivery of the dose; A dose delivery mechanism according to embodiment 10.

[0392] EMBODIMENT 12 an actuation member (18) configured to be moved, e.g., in a proximal direction, to initiate delivery of the set dose; the actuating member (18) is prevented from initiating delivery of the set dose when the dose setting member (34) is in a preset position; A dose delivery mechanism (54) according to any one of embodiments 1 to 11.

[0393] EMBODIMENT 13 A separate member (30), e.g. a clip, is provided to prevent premature movement of the actuating member (18) relative to the housing (32), e.g. by the dose delivery mechanism (54) falling off its proximal end (14) before the separate member (32) is removed; A dose delivery mechanism (54) according to embodiment 12.

[0394] EMBODIMENT 14 two parts (24, 28) arranged inside the housing (32) of the dose delivery mechanism (54) are configured to cooperate with each other to prevent the actuating member (18) from moving unintentionally, e.g. in a proximal direction, relative to the housing (32) starting from a preset position; A dose delivery mechanism (54) according to embodiment 12 or 13.

[0395] EMBODIMENT 15 a first of the two parts forms a blocking structure (156), in particular a circumferentially extending rib (156), and a second of the two parts forms an engagement mechanism (116) configured to engage with the blocking structure (156) when the two parts move relative to each other to prevent the actuating member (18) from initiating delivery of the set dose when the dose setting member (34) is in a preset position; A dose delivery mechanism (54) according to embodiment 14.

[0396] EMBODIMENT 16 a notch is provided in the blocking structure at a position, e.g. an angular position, where the engagement mechanism is located when a dose other than the preset dose, e.g. a therapeutic dose, is set, such that the engagement mechanism can be moved past the blocking structure through the relevant notch upon delivery of the set dose; A dose delivery mechanism according to embodiment 15.

[0397] EMBODIMENT 17 The notches are provided adjacent to corresponding dose-defining elements. A dose delivery mechanism according to embodiment 16.

[0398] EMBODIMENT 18 The engagement mechanism is provided on the snap element. Dose delivery mechanism according to embodiments 15-17.

[0399] EMBODIMENT 19 two parts arranged inside the housing (32) of the dose delivery mechanism (54) are provided with respective dose defining elements (116, 118a-118d) configured to cooperate with each other to define a number of relative positions with respect to each other corresponding to settable doses; A dose delivery mechanism (54) according to any one of embodiments 1 to 18.

[0400] EMBODIMENT 20 two parts arranged inside the housing of the dose delivery mechanism configured to cooperate with each other to prevent the actuating member from unintentionally moving, e.g. in a proximal direction, relative to the housing starting from a preset position, are two parts with respective dose defining elements configured to cooperate with each other to define a number of relative positions with respect to each other corresponding to settable doses, A dose delivery mechanism according to embodiments 14 and 19.

[0401] EMBODIMENT 21 The position is defined by a dose stopper (118a-118d) formed on a first of the two parts and configured to contact a snap element (116) on a second of the two parts, A dose delivery mechanism (54) according to embodiment 19 or 20.

[0402] EMBODIMENT 22 The snap elements (116) are preloaded against the respective dose stops (118a-118d) by a spring (40), in particular a torsion spring. A dose delivery mechanism according to embodiment 21.

[0403] EMBODIMENT 23 at least one of the dose stops has a chamfered surface for guiding the snap element over the dose stop when setting a higher dose; and / or at least one of the dose stops has a surface opposite a chamfered surface configured to allow movement of a snap element when setting a smaller dose; 23. The dose delivery mechanism according to embodiment 21 or 22.

[0404] EMBODIMENT 24 the two parts being configured to cooperate with one another to prevent unintentional movement of one of the parts relative to the other of the parts, such that the actuating member is prevented from moving relative to the housing starting from a preset position; Dose delivery mechanism according to embodiments 19-23.

[0405] EMBODIMENT 25 At the end of the dose delivery procedure, the dose delivery mechanism is configured to reach a zero dose state. A dose delivery mechanism according to any one of embodiments 1 to 24.

[0406] EMBODIMENT 26 At the end of the dose delivery procedure, the dose indicating member indicates that the dose delivery mechanism is in the zero dose position. A dose delivery mechanism according to any one of embodiments 1 to 25.

[0407] EMBODIMENT 27 the dose delivery mechanism comprises a nut in mating engagement with the piston rod; Axial movement of the nut relative to the piston rod corresponds to the amount of the dose set by the dose delivery mechanism. A dose delivery mechanism according to any one of embodiments 1 to 26.

[0408] EMBODIMENT 28 The piston rod is non-rotatably mounted in the housing. A dose delivery mechanism according to embodiment 27.

[0409] EMBODIMENT 29 The piston rod is linearly guided within the housing. 29. The dose delivery mechanism according to embodiment 27 or 28.

[0410] EMBODIMENT 30 The nut is configured not to rotate relative to the housing and the piston rod during delivery of a dose. A dose delivery mechanism according to any one of embodiments 27 to 29.

[0411] EMBODIMENT 31 a driver configured to apply a force to the nut to move the piston rod proximally through the nut is rotated relative to the housing during delivery of the dose; A dose delivery mechanism according to any one of embodiments 1 to 30.

[0412] EMBODIMENT 32 The dose delivery mechanism is configured to be disposable after a single use. A dose delivery mechanism according to any one of embodiments 1 to 31.

[0413] EMBODIMENT 33 A medicine delivery device (10), in particular an injection device, comprising a dose delivery mechanism (54) according to any one of the embodiments 1 to 32.

[0414] EMBODIMENT 34 An assembly of a dose delivery mechanism and a removable element, e.g. a clip, The dose delivery mechanism is Housing and a piston rod configured to move axially relative to the housing to act on a plunger that seals the fluid compartment and to deliver a set dose; a dose setting member movable relative to the piston rod and defining a set dose by its position relative to the housing; an actuation member movable relative to the housing, particularly in a proximal direction, to deliver a set dose; Equipped with The assembly, wherein the removable element is disposed between the housing and the actuating member and prevents premature movement of the actuating member relative to the housing, particularly in said proximal direction, before the removable element is detached.

[0415] EMBODIMENT 35 a cover, the cover being mechanically attached to the dose delivery mechanism prior to use of the dose delivery mechanism; the cover is configured to cover at least a portion of the dose delivery mechanism and / or at least a portion of the removable element so as to prevent removal of the removable element from the dose delivery mechanism; the cover is configured to be movable to expose said portion of the dose delivery mechanism and / or said portion of the removable element such that the removable element can be removed from the dose delivery mechanism. An assembly according to embodiment 34.

[0416] EMBODIMENT 36 Housing and a dose adjustment member movable relative to the housing to adjust the dose and / or an actuation member for delivering a set dose; a dose indicating member indicating a dose set by its rotational position relative to the housing; It is equipped with A dose delivery mechanism that is preset to a dose greater than zero as delivered.

[0417] EMBODIMENT 37 In the as-delivered state, the dose adjustment member and / or the actuation member are preset to a position corresponding to a dose greater than zero. A dose delivery mechanism according to embodiment 36.

[0418] EMBODIMENT 38 In the as-delivered state, the dose delivery mechanism is preset to a dose between zero dose and a minimum dose, e.g., a minimum dose per treatment for which the dose delivery mechanism is intended. A dose delivery mechanism according to embodiment 35 or 36.

[0419] EMBODIMENT 39 A dose delivery mechanism according to any one of embodiments 36 to 38, wherein in the as-delivered state, the dose indicating member indicates a set dose as different from a zero dose.

[0420] EMBODIMENT 40 A dose delivery mechanism according to embodiment 39, wherein the dose indicating member in the as-delivered state indicates the set dose to be between zero dose and a minimum dose, e.g. a minimum dose per treatment for the purpose of the dose delivery mechanism.

[0421] EMBODIMENT 41 the dose adjusting member and the actuating member are fixedly connected to each other or are integrally formed with each other; A dose delivery mechanism according to any one of embodiments 36 to 40.

[0422] EMBODIMENT 42 Housing and a dose adjustment member movable relative to the housing to set a dose and / or an actuation member to deliver a set dose; a dose indicating member indicating a dose set by its rotational position relative to the housing; 1. A method for providing a dose delivery mechanism having Delivering the dose delivery mechanism to the customer with the dose preset to greater than zero. The method includes:

[0423] EMBODIMENT 43 An assembly of a dose delivery mechanism and a removable element, e.g. a clip, The dose delivery mechanism is Housing and a dose indicating member indicating a dose set by its rotational position relative to the housing; an actuating member movable relative to the housing, particularly in a proximal direction, to deliver a set dose; Equipped with The assembly, wherein the removable element is disposed between the housing and the actuating member and prevents premature movement of the actuating member relative to the housing, particularly in said proximal direction, before the removable element is detached.

[0424] EMBODIMENT 44 a cover, the cover being mechanically attached to the dose delivery mechanism prior to use of the dose delivery mechanism; the cover is configured to cover at least a portion of the dose delivery mechanism and / or at least a portion of the removable element so as to prevent removal of the removable element from the dose delivery mechanism; the cover is configured to be movable to expose said portion of the dose delivery mechanism and / or said portion of the removable element such that the removable element can be removed from the dose delivery mechanism. 44. An assembly according to embodiment 43.

[0425] EMBODIMENT 45 A housing (32); a piston rod (44) configured to move axially relative to the housing (32) to act on a plunger (46) that seals the fluid compartment (48) and to deliver a set dose; a dose setting member (34) movable relative to a piston rod (44); It is equipped with 1. A method for providing a dose delivery mechanism (54) that defines a set dose by the position of a dose setting member (34) relative to a housing (32), comprising: delivering the dose delivery mechanism (54), in particular the medicine delivery device (10) comprising the dose delivery mechanism (54), to the customer with a preset dose greater than zero. The method includes:

Claims

1. a piston rod (44) and a nut (38), the piston rod (44) forming external threads (190) that mate with internal threads (192) of the nut (38), the nut (38) configured to rotate relative to the piston rod (44) to advance the nut (38) distally a first distance relative to the piston rod (44) during dose setting; an actuation member (18, 20, 22) that can be moved by a user to achieve delivery of a set dose; A housing (32) and It is equipped with a second threaded connection (170, 172) is provided; the second threaded connection (170, 172) is configured to move the actuation member (18, 20, 22) a second distance in a distal direction during dose setting; the actuating member (18, 20, 22) is coupled to the piston rod (44) via the nut (38) during dose delivery, and when the actuating member (18, 20, 22) moves proximally the second distance, it advances the piston rod (44) proximally the first distance; The second distance is less than 1.5 times the first distance.

2. The dose delivery mechanism (54) of claim 1, wherein the first distance is essentially equal to the second distance.

3. A dose delivery mechanism (54) as described in claim 1 or 2, wherein all parts configured to rotate relative to the housing (32) during dose delivery, such as the driver (36), the dose sleeve (34), and the snap element (24), are connected to the housing (32) via exactly one threaded connection (170, 172).

4. a dose setting unit having a dose sleeve (34) indicative of a set dose, rotationally coupled to said actuating member (18, 20, 22) during dose setting, said actuating member (18, 20, 22) and said dose sleeve (34) being rotatable to set a desired dose; In particular, the dose sleeve (34) and the actuating member (18, 20, 22) are rotationally decoupled during dose delivery so that the actuating member (18, 20, 22) does not rotate during dose delivery. A dose delivery mechanism (54) as described in claim 1 or 2.

5. The dose delivery mechanism (54) further comprises a driver (36), the driver (36) exerting a force on the nut (38) to drive the piston rod (44) during dose delivery; the dose sleeve (34) and the driver (36) form one part or are rigidly connected to each other in the axial direction and in the rotation direction; In particular, the driver (36) directly abuts the nut (38) to drive the piston rod (44) during dose delivery, and / or 5. The dose delivery mechanism (54) of claim 4, wherein the driver (36) is rotated relative to the housing (32) during dose delivery.

6. a spring (40) acting between the housing (32) and the actuating member (18, 20, 22) when setting a dose; A dose delivery mechanism (54) according to claim 1 or 2, in particular, wherein the spring (40) is provided between the housing (32, 42) and the dose sleeve (34) or between the housing (32, 42) and the driver (36).

7. 7. The dose delivery mechanism (54) of claim 6, wherein the spring (40) is configured to assist a user in moving the actuation member (18, 20, 22) to achieve delivery of a set dose.

8. said spring (40) is a torsion spring, in particular a helical torsion spring, and / or 7. The dose delivery mechanism (54) of claim 6, wherein the spring (40) is configured to be tensioned during setting of a dose.

9. the spring (40) is coupled to a piston rod guide (42) and a driver (36) that guides the linear movement of the piston rod (44); and / or 7. A dose delivery mechanism (54) according to claim 6, wherein the spring (40) is arranged in a proximal portion of the mechanism, in particular in a proximal end portion.

10. 3. A dose delivery mechanism (54) according to claim 1 or 2, wherein the actuating member (18, 20, 22) is rotationally fixed to the nut (38) during dose setting and dose delivery.

11. A dose delivery mechanism (54) as described in claim 1 or 2, wherein the driver (36) and the housing (32, 42) form the second threaded connection (170, 172), preferably the driver (36) and an inner housing portion, in particular an inner housing portion arranged radially inside the dose sleeve (34), form the second threaded connection (170, 172).

12. the housing (32, 42) has a longitudinal through opening (186) with a non-circular inner periphery that corresponds to the non-circular outer periphery (188) of the piston rod (44); and / or 3. A dose delivery mechanism (54) according to claim 1 or 2, wherein ball bearings and / or sliding elements made of low-friction material are provided to reduce friction during dose delivery.

13. the velocity v of said actuating members (18, 20, 22) during dose delivery; ａｍ and the velocity v of the piston rod (44) ｐｒ 3. The dose delivery mechanism (54) of claim 1 or 2, wherein:

14. 3. The dose delivery mechanism (54) of claim 1 or 2, wherein the piston rod (44) is linearly guided within the housing (32, 42) and / or the piston rod (44) is non-rotatably attached to the housing (32, 42).

15. 3. The dose delivery mechanism (54) of claim 1 or 2, wherein the nut (38) is configured not to rotate relative to the housing (32, 42) and / or the piston rod (44) during dose delivery.

16. 3. The dose delivery mechanism (54) of claim 1 or 2, wherein when the actuating member (18, 20, 22) moves proximally by the second distance, the actuating member (18, 20, 22) is configured to apply an axial force to a driver (36) during dose delivery to advance the piston rod (44) proximally by the first distance, the driver (36) is configured to apply the axial force to the nut (38), and the nut (38) is configured to apply the axial force to the piston rod (44) via the male thread (190) and the female thread (192).

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