Injection Device with a Filling Level Indicator

Abstract

The present disclosure relates to an injection device for setting and injecting of a dose of a medicament. The injection device includes an elongated housing extending along a longitudinal direction and configured to accommodate a cartridge, a first member movably arranged inside the elongated housing for setting of the dose, and a second member, and a piston rod configured to advance in a longitudinal distal direction and operable to exert a distally directed pressure onto a bung of the cartridge for expelling of the dose. Depending on the setting, the first member is rotatable relative to the second member or is rotationally locked to the second member. The injection device includes a filling level indicator threadedly engaged with one of the first member and the second member, the filling level indicator being rotationally locked and longitudinally slidingly engaged with the other one of the first member and the second member.

Claims

1.-15. (canceled)

16. An injection device for setting and injecting a dose of a medicament, the injection device comprising: an elongated housing extending along a longitudinal direction, the elongated housing being configured to accommodate a cartridge; a first member movably arranged inside the elongated housing for setting of the dose; a second member; a piston rod configured to advance in a longitudinal distal direction and operable to exert a distally directed pressure onto a bung of a cartridge for expelling the dose, wherein during one of setting the dose and expelling the dose the first member is rotatable relative to the second member, and wherein during the other one of setting the dose and expelling the dose the first member is rotationally locked to the second member; and a filling level indicator threadedly engaged with one of the first member and the second member and wherein the filling level indicator is rotationally locked and longitudinally slidingly engaged with the other one of the first member and the second member, wherein the filling level indicator is movable in a longitudinal direction at least from a start position to an end position relative to at least one of the first member and the second member, and wherein the filling level indicator is visible from outside the elongated housing when the filling level indicator is in the start position.

17. The injection device of claim 16, wherein the filling level indicator is visible from outside the elongated housing when the filling level indicator is in the end position.

18. The injection device of claim 16, wherein the filling level indicator is visible from outside the elongated housing in any position between the start position and the end position.

19. The injection device of claim 16, wherein one of the first member and the second member comprises a first stop and a second stop, wherein the first stop and the second stop are separated from each other along the longitudinal direction.

20. The injection device of claim 19, wherein the filling level indicator engages the second stop when in the end position, and wherein the filling level indicator is operable to prevent a further movement of the first member relative to the second member at least with regard to one direction of movement when the filling level indicator is engaged with the second stop.

21. The injection device of claim 16, wherein the elongated housing comprises an elongated aperture extending along the longitudinal direction, and wherein at least an indicating portion of the filling level indicator is visible through the elongated aperture.

22. The injection device of claim 21, wherein the elongated aperture is covered or closed by a transparent window.

23. The injection device of claim 16, wherein the elongated housing comprises an elongated aperture extending along the longitudinal direction, and wherein at least an indicating portion of the filling level indicator is located outside the elongated housing.

24. The injection device of claim 23, wherein the filling level indicator comprises a L-shaped rod comprising the indicating portion and a bridging portion, wherein the bridging portion extends through the aperture.

25. The injection device of claim 23, further comprising an outer housing covering or enclosing at least a portion of the elongated housing in a region of the filling level indicator, wherein the outer housing comprises a transparent window overlapping at least with the indicating portion of the filling level indicator.

26. The injection device of claim 16, wherein the elongated housing comprises a cartridge holder configured to accommodate the cartridge, wherein the cartridge holder is opaque.

27. The injection device of claim 21, wherein the elongated housing comprises a scale extending along the elongated aperture, and wherein the indicating portion comprises a pointer pointing towards the scale.

28. The injection device of claim 16, wherein the filling level indicator comprises a threaded section and at least one of a radial protrusion and a radial recess.

29. The injection device of claim 28, wherein the threaded section is engaged with a correspondingly shaped counter threaded section of the one of the first member and the second member.

30. The injection device of claim 28, wherein the at least one of the radial protrusion and the radial recess is in a longitudinal sliding engagement with a correspondingly shaped radial recess or the radial protrusion of other one of the first member and the second member.

31. The injection device of claim 16, wherein the first member is movable relative to the second member only during one of setting the dose and dispensing the dose.

32. The injection device of claim 16, further comprising the cartridge arranged inside the elongated housing, the cartridge being filled with the medicament.

33. A method for setting and injecting a dose of a medicament using an injection device, the method comprising: setting the dose by rotating a first member relative to the second member, wherein the first member is movably arranged inside the elongated housing for setting the dose; advancing a piston rod in a longitudinal distal direction to exert a distally directed pressure onto a bung of a cartridge for expelling of the dose by rotationally locking the first member to the second member; and threadedly engaging a filling level indicator with one of the first member and the second member, wherein the filling level indicator is rotationally locked and longitudinally slidingly engaged with the other one of the first member and the second member, the filling level indicator being movable in a longitudinal direction at least from a start position to an end position relative to at least one of the first member and the second member, and wherein the filling level indicator is visible from outside the elongated housing when the filling level indicator is in the start position.

34. The method of claim 33, further comprising: engaging by the filling level indicator the second stop when in the end position; and preventing by the filling level indicator a further movement of the first member relative to the second member at least with regard to one direction of movement when the filling level indicator is engaged with the second stop.

35. The method of claim 33, further comprising: bringing the filling level indicator in the end position in which the filling level indicator is visible from outside the elongated housing.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0151] In the following, numerous examples of the injection device comprising a filling level indicator will be described in greater detail by making reference to the drawings, in which:

[0152] FIG. 1 shows an example of an injection device,

[0153] FIG. 2 shows the injection device of FIG. 1 in an exploded perspective view,

[0154] FIG. 3 shows a cross-section through the injection device,

[0155] FIG. 4 is an enlarged view of a portion of FIG. 3 with the filling level indicator in an initial configuration,

[0156] FIG. 5 is an illustration corresponding to FIG. 4 with the filling level indicator in an intermediate configuration,

[0157] FIG. 6 is an enlarged view of a portion of the housing of the injection device according to FIG. 4 as seen from outside

[0158] FIG. 7 is an enlarged view of a portion of the housing of the injection device according to FIG. 5 as seen from outside

[0159] FIG. 8 is a transverse cross-section through the filling level indicator engaged with the housing,

[0160] FIG. 9 is a longitudinal cross-section through a further example of the filling level indicator and

[0161] FIG. 10 is a transverse cross-section through the filling level indicator according of FIG. 9.

DETAILED DESCRIPTION

[0162] One of a plurality of examples of an injection device 1 suitable for implementation of a filling level indication of a cartridge is shown in FIGS. 1 and 2. The injection device 1 is a pre-filled disposable injection device that comprises a housing 90 to which an injection needle 15 can be affixed. The housing 90 comprises a body 10 forming a proximal end of the housing and a cartridge holder 14 forming a distal end of the injection device 1. The injection needle 15 is protected by an inner needle cap 16 and either an outer needle cap 17 and/or a protective cap 18 that is configured to enclose and to protect a distal section of the housing 90 of the injection device 1. The housing 90 comprises the body 10 configured to accommodate a drive mechanism 8 as shown in FIG. 2. The distal housing component is commonly denoted as a cartridge holder 14. The cartridge holder 14 may be permanently or releasably connected to the body 10.

[0163] The body 10 may form or constitute a main body or main housing of the injection device 10. Furthermore, the body 10 may form or constitute a second member according to the terminology of the present disclosure. The cartridge holder 14 can be configured to accommodate a cartridge 6 that is filled with a liquid medicament. The cartridge 6 comprises a cylindrically shaped or tubular-shaped barrel 25 sealed in proximal direction 3 by a bung 7 located inside the barrel 25. The bung 7 is displaceable relative to the barrel 25 of the cartridge 6 in a distal direction 2 by a piston rod 20. A distal end of the cartridge 6 is sealed by a pierceable seal 26 configured as a septum and being pierceable by a proximally directed tipped end of the injection needle 15. The cartridge holder 14 comprises a threaded socket 28 at its distal end to threadedly engage with a correspondingly threaded portion of the injection needle 15. By attaching the injection needle 15 to the distal end of the cartridge holder 14 the seal 26 of the cartridge 6 is penetrated thereby establishing a fluid transferring access to the interior of the cartridge 6.

[0164] When the injection device 1 is configured to administer e.g. human insulin, the dosage set by a dose dial 12 at a proximal end of the injection device 1 may be displayed in so-called international units (IU), wherein 1 IU is the biological equivalent of about 45.5 μg of pure crystalline insulin (1/22 mg). The dose dial 12 may be rotatable relative to the housing 90 or body 10 with regard to a longitudinal axis.

[0165] As shown further in FIGS. 1 and 2, the body 10 comprises a dosage window 13 that may be in the form of an aperture in the body 10. The dosage window 13 permits a user to view a limited portion of a number sleeve 80 that is configured to move when the dose dial 12 is turned, to provide a visual indication of a currently set dose. The dose dial 12 is rotated on a helical path with respect to the body 10 when turned during setting and/or dispensing or expelling of a dose.

[0166] The injection device 1 may be configured so that turning the dosage knob or dose dial 12 causes a mechanical click sound to provide acoustical feedback to a user. The number sleeve 80 mechanically interacts with a piston in the insulin cartridge 6. When the needle 15 is stuck into a skin portion of a patient, and when the trigger 11 or injection button is pushed, the insulin dose displayed in display window 13 can be ejected from injection device 1. When the needle 15 of the injection device 1 remains for a certain time in the skin portion after the trigger 11 is pushed, a high percentage of the dose is actually injected into the patient's body. Ejection of an insulin dose may also cause a mechanical click sound, which is however different from the sounds produced when using the dose dial 12.

[0167] In this embodiment, during delivery of the insulin dose, the dose dial 12 is turned to its initial position in an axial movement, that is to say without rotation, while the number sleeve 80 is rotated to return to its initial position, e.g. to display a dose of zero units.

[0168] The injection device 1 may be used for several injection processes until either the cartridge 6 is empty or the expiration date of the medicament in the injection device 1 (e.g. 28 days after the first use) is reached.

[0169] Furthermore, before using injection device 1 for the first time, it may be necessary to perform a so-called “prime shot” to remove air from the cartridge 6 and the needle 15, for instance by selecting two units of the medicament and pressing trigger 11 while holding the injection device 1 with the needle 15 upwards. For simplicity of presentation, in the following, it will be assumed that the ejected amounts substantially correspond to the injected doses, so that, for instance the amount of medicament ejected from the injection device 1 is equal to the dose received by the user.

[0170] An example of the drive mechanism 8 is illustrated in more detail in FIG. 2. It comprises numerous mechanically interacting components. A flange like support of the body 10 comprises a threaded axial through opening threadedly engaged with a first thread or distal thread 22 of the piston rod 20. The distal end of the piston rod 20 comprises a bearing 21 on which a pressure foot 23 is free to rotate with the longitudinal axis of the piston rod 20 as an axis of rotation. The pressure foot 23 is configured to axially abut against a proximally facing thrust receiving face of the bung 7 of the cartridge 6. During a dispensing action the piston rod 20 rotates relative to the body 10 thereby experiencing a distally directed advancing motion relative to the body 10 and hence relative to the barrel 25 of the cartridge 6. As a consequence, the bung 7 of the cartridge 6 is displaced in distal direction 2 by a well-defined distance due to the threaded engagement of the piston rod 20 with the body 10.

[0171] The piston rod 20 is further provided with a second thread 24 at its proximal end. The distal thread 22 and the proximal thread 24 are oppositely handed.

[0172] The injection device 1 includes a dose setting member 30, e.g. forming or constituting a drive sleeve. The dose setting member 30 or drive sleeve may form or constitute a first member according to the terminology of the present disclosure. Here, the first member 30, e.g. in form of the dose setting member 30 or drive sleeve, has a hollow interior to receive the piston rod 20.

[0173] The dose setting member 30 comprises an inner thread which is threadedly engaged with the proximal thread 24 of the piston rod 20. Moreover, the dose setting member 30 comprises an outer threaded section 31 at its distal end. The threaded section 31 is axially confined between a first stop 32 and a second stop 33. The first stop 32 comprises distal flange portion. The second stop 33 comprises a proximal flange portion located at a predefined axial distance from the distal flange portion 32. Between the two flange portions 32, 33 there is provided a filling level indicator 35. In the present example the filling level indicator 35 comprises a semi-circular nut having an internal thread 38 mating the threaded section 31 of the dose setting member 30. The filling level indicator 35 may also form or constitute a last dose limiter e.g. in form of a last dose nut.

[0174] The filling level indicator 35 further comprises a radial recess or protrusion 39 at its outer circumference to engage with a complementary-shaped recess 99 or protrusion at an inside of the sidewall of the body 10. In this way the filling level indicator 35 is splined to the body 10. A rotation of the dose setting member 30 in a dose incrementing direction 4 or clockwise direction during consecutive dose setting procedures leads to an accumulative axial displacement of the filling level indicator 35 relative to the dose setting member 30. There is further provided an annular spring 40 that is in axial abutment with a proximally facing surface of the flange portion 33. Moreover, there is provided a tubular-shaped clutch 60. At a first end the clutch 60 is provided with a series of circumferentially directed saw teeth. Towards a second opposite end of the clutch 60 there is located a radially inwardly directed flange.

[0175] Furthermore, there is provided a dose dial sleeve also denoted as number sleeve 80. The number sleeve 80 is provided outside of the spring 40 and the clutch 60 and is located radially inward of the body 10. A helical groove 81 is provided about an outer surface of the number sleeve 80. The body 10 is provided with the dosage window 13 through which a part of the outer surface of the number 80 can be seen. The body 10 is further provided with a helical rib at an inside sidewall portion of an insert piece 62, which helical rib is to be seated in the helical groove 81 of the number sleeve 80. The tubular shaped insert piece 62 is inserted into the proximal end of the body 10. It is rotationally and axially fixed to the body 10. There are provided first and second stops on the body 10 to limit a dose setting procedure during which the number sleeve 80 is rotated in a helical motion relative to the body 10.

[0176] The dose dial 12 in form of a dose dial grip is disposed about an outer surface of the proximal end of the number sleeve 80. An outer diameter of the dose dial 12 typically corresponds to and matches with the outer diameter of the body 10. The dose dial 12 is secured to the number 80 to prevent relative movement there between. The dose dial 12 is provided with a central opening.

[0177] The trigger 11, also denoted as dose button is substantially T-shaped. It is provided at a proximal end of the injection device 10. A stem 64 of the trigger 11 extends through the opening in the dose dial 12, through an inner diameter of extensions of the dose setting member 30 and into a receiving recess at the proximal end of the piston rod 20. The stem 64 is retained for limited axial movement in the dose setting member 30 and against rotation with respect thereto. A head of the trigger 11 is generally circular. The trigger side wall or skirt extends from a periphery of the head and is further adapted to be seated in a proximally accessible annular recess of the dose dial 12.

[0178] To dial a dose a user rotates the dose dial 12. With the spring 40 also acting as a clicker and the clutch 60 engaged, the dose setting member 30, the spring or clicker 40, the clutch 60 and the number sleeve 80 rotate with the dose dial 12. Audible and tactile feedback of the dose being dialed is provided by the spring 40 and by the clutch 60. Torque is transmitted through saw teeth between the spring 40 and the clutch 60. The helical groove 81 on the number sleeve 80 and a helical groove in the dose setting member 30 have the same lead. This allows the number sleeve 80 to extend from the body 10 and the dose setting member 30 to climb the piston rod 20 at the same rate. At a limit of travel a radial stop on the number sleeve 80 engages either with a first stop or a second stop provided on the body 10 to prevent further movement in a first sense of rotation, e.g. in a dose incrementing direction 4. Rotation of the piston rod 20 is prevented due to the opposing directions of the overall and driven threads on the piston rod 20.

[0179] The filling level indicator 35 keyed to the body 10 is advanced along the threaded section 31 by the rotation of the dose setting member 30. When a final dose dispensing position is reached, a radial stop formed on a surface of the filling level indicator 35 may abut a radial stop on the second stop 33 or proximal flange portion of the dose setting member 30, preventing both, the filling level indicator 35 and the dose setting member 30 from rotating further.

[0180] Should a user inadvertently dial beyond the desired dosage, the injection device 1, configured as a pen-injector allows the dosage to be dialed down without dispense of the medicament from the cartridge 6. For this the dose dial 12 is simply counter-rotated. This causes the system to act in reverse. A flexible arm of the spring or clicker 40 then acts as a ratchet preventing the spring 40 from rotating. The torque transmitted through the clutch 60 causes the saw teeth to ride over one another to create the clicks corresponding to dialed dose reduction. Typically, the saw teeth are so disposed that a circumferential extent of each saw tooth corresponds to a unit dose. Here, the clutch may serve as a ratchet mechanism.

[0181] As an alternative or in addition the ratchet mechanism may comprise at least one ratchet feature, such as a flexible arm on the sidewall of the tubular-shaped clutch 60. The at least one ratchet feature may comprise a radially outwardly extending protrusion e.g. on a free end of the flexible arm. The protrusion is configured to engage with a correspondingly shaped counter ratchet structure on an inside of the number sleeve 80. The inside of the number sleeve 80 may comprise longitudinally shaped grooves or protrusions featuring a saw-tooth profile. During dialing or setting of a dose the ratchet mechanism allows and supports a rotation of the number sleeve 80 relative to the clutch 60 along a second sense of rotation 5, which rotation is accompanied by a regular clicking of the flexible arm of the clutch 60. An angular momentum applied to the number sleeve 80 along the first sense of rotation for is unalterably transferred to the clutch 60. Here, the mutually corresponding ratchet features of the ratchet mechanism provide a torque transmission from the number sleeve 80 to the clutch 60.

[0182] When the desired dose has been dialed the user may simply dispense the set dose by depressing the trigger 11. This displaces the clutch 60 axially with respect to the number sleeve 80 causing dog teeth thereof to disengage. However, the clutch 60 remains keyed in rotation to the dose setting member 30. The number sleeve 80 and the dose dial 12 are now free to rotate in accordance with the helical groove 81.

[0183] The axial movement deforms the flexible arm of the spring 40 to ensure the saw teeth cannot be overhauled during dispense. This prevents the dose setting member 30 from rotating with respect to the body 10 though it is still free to move axially with respect thereto. The deformation is subsequently used to urge the spring 40 and the clutch 60 back along the dose setting member 30 to restore the connection between the clutch 60 and the number sleeve 80 when the distally directed dispensing pressure is removed from the trigger 11.

[0184] The longitudinal axial movement of the dose setting member 30 causes the piston rod 20 to rotate through the through opening of the support of the body 10, thereby to advance the bung 7 in the cartridge 6. Once the dialed dose has been dispensed, the number sleeve 80 is prevented from further rotation by contact of at least one stop extending from the dose dial 12 with at least one corresponding stop of the body 10. A zero dose position may be determined by the abutment of one of axially extending edges or stops of the number sleeve 80 with at least one or several corresponding stops of the body 10.

[0185] The expelling mechanism or drive mechanism 8 as described herein is only exemplary for one of a plurality of differently configured drive mechanisms that are generally implementable in a disposable pen-injector. The drive mechanism as described above is explained in more detail e.g. in WO2004/078239A1, WO 2004/078240A1 or WO 2004/078241A1 the entirety of which being incorporated herein by reference.

[0186] Generally, the filling level indicating mechanism as disclosed herein is implementable with any injection device comprising a first member 30 and a second member 10, wherein the first member 30 rotates relative to the second member 10 during and/or for only one of setting of the dose and expelling of the dose and wherein the first member 30 is rotationally locked to the second member 10 during and/or for only one of the other one of setting of the dose and expelling of the dose. .sub.[IG1]Any reference to a dose setting member 30 may equally apply to the first member. Moreover, any reference to a body 10 or housing 90 may equally apply to the second member according to the terminology of the appended claims.

[0187] The dose setting mechanism 9 as illustrated in FIG. 2 comprises at least the dose dial 12 and the number sleeve 80. As the dose dial 12 is rotated during and for setting of a dose the number sleeve 80 starts to rotate relative to the housing along a helical path as defined by the threaded engagement of its outer thread or helical groove 81 with a correspondingly shaped threaded section at the inside surface of the housing.

[0188] During dose setting and when the drive mechanism 8 or the dose setting mechanism 9 is in the dose setting mode the dose setting member 30 rotates in unison with the dose dial 12 and with the number sleeve 80. The dose setting member 30 is threadedly engaged with the piston rod 20, which during dose setting is stationary with regard to the body 10. Accordingly, the dose setting member 30 is subject to a screwing or helical motion during dose setting. The dose setting member 30 starts to travel in proximal direction as the dose dial is rotated in a first sense or rotation or in a dose incrementing direction 4, e.g. in a clockwise direction. For adjusting of or correcting a size of a dose the dose dial 12 is rotatable in an opposite second sense of rotation, hence in a dose decrementing direction 5, e.g. counterclockwise.

[0189] In the example of FIGS. 1-5 a proximal end of the cartridge holder 14 is connectable or is permanently connected to a distal end of the body 10. For this, the cartridge holder 14 may comprise an insert section configured to be inserted in a receptacle provided at the distal end of the body 10. The cartridge holder 14 and the body 10 can be detachably or releasably engaged.

[0190] With some examples the cartridge holder 14 and the body 10 are permanently and/or non-releasably or non-detachably engaged, e.g. by a snap-fit interconnection and/or by a force fitting engagement, e.g. provided by an adhesive or by mutual welding of overlapping portions of the cartridge holder 14 and the body 10. With examples, wherein the cartridge holder 14 and the body 10 are non-detachably interconnected the injection device one is implemented as a disposable injection device intended to be discarded in its entirety once the content of the cartridge has been used up or should no longer be used.

[0191] The first member 30 and hence the dose setting member 30 may be implemented as a drive sleeve and is configured to rotate in a dose incrementing direction during setting of a dose. For correcting of a dose of the dose setting member may be rotatable in an opposite, hence in a dose decrementing direction relative to the first member and hence relative to the housing 90 or body 10. During dose expelling or dose dispensing the dose setting member 30 can be rotationally locked to the housing.

[0192] The filling level indicator 35 of the injection device 1 is engaged with the dose setting member 30. The filling level indicator 35 is further engaged with the elongated housing 90, in particular with the proximally located tubular shaped body 10. In the illustration of FIG. 4 the filling level indicator 35 is located in a start position 100. There, it is in abutment with a first stop 32 provided on the dose setting member 30. The position, in particular the start position 100 of the filling level indicator 35 is discernible from outside the housing through an elongated aperture 91 provided in the sidewall of the housing 90, in particular in a sidewall of the body 10 as indicated in FIGS. 4-7.

[0193] In the present example the filling level indicator 35; 135 provides a twofold function. On the one hand it provides the function of a last dose member or last dose nut. On the other hand the filling level indicator 35; 135 is indicative of the filling level of the medicament provided in the cartridge 6. Here, the longitudinal position of the filling level indicator 35; 135 relative to the housing 90 or body 10 directly correlates with the longitudinal position of the piston rod 20 relative to the housing 90 or body 10. The filling level indicator is visually inspectable and/or discernable from outside the housing 90 in each configuration of the injection device.

[0194] In FIGS. 4-10 various examples of a filling level indicator 35; 135 are illustrated in connection with one particular example of an injection device 1. Generally, one of the presently disclosed concepts of a filling level indicator 35; 135 is implementable with a variety of different injection devices. With some examples and for the implementation of the filling level indicator 35; 135 there is only required a first member 30, e.g. a dose setting member 30 being rotatable in a dose incrementing direction relative to a second member 10, e.g. a body 10 during setting of a dose and being non-rotatable during dose expelling or dose injection. With other examples the first member is rotationally locked to the second member 10 during and/or for setting of the dose. The first member is then rotatable relative to the second member 20 during and/or for expelling of the dose.

[0195] In the presently illustrated non-limiting example the filling level indicator 35 is threadedly engaged with the dose setting member 30. For this, the filling level indicator 35 comprises an inner threaded section 38 threadedly engaged with a correspondingly shaped outer threaded section 31 of the dose setting member 30. The dose setting member 30 comprises a tubular or sleeve-shaped geometrical structure.

[0196] The threaded section 31 extends in longitudinal direction on the outside surface of the dose setting member 30. The threaded section 31 is delimited in proximal direction 3 by the second stop 33. The threaded section 31 is delimited in distal direction 2 by the first stop 32. In the presently illustrated example the first stop 32 comprises a radially outwardly extending flange portion integrally formed with the dose setting member 30. Likewise also the second stop 33 is implemented as a radially outwardly extending flange portion. In particular and as illustrated in FIG. 4, there may be provided a stop feature 29 of a distally pointing side of the second stop 33.

[0197] The stop feature 34 may comprise a stop surface, wherein the stop surface extends in longitudinal and radial direction. Hence, the surface normal of the stop surface of the stop feature 29 extends in tangential or circumferential direction.

[0198] The filling level indicator 35 may comprise a semicircular-shaped half-nut as illustrated in FIG. 8.

[0199] The filling level indicator 35 may be either axially engageable with the second stop 33, in particular with the distally directed surface of the flange. Alternatively or additionally the filling level indicator 35 may comprise a stop feature 44, 45 at a circumferential or tangential end configured to abut in tangential or circumferential direction with the stop feature 29 of the second stop 33. In this way, a rather abrupt and well-defined stop configuration can be provided as the filling level indicator 35 reaches an end position 102 as indicated in FIG. 6 by the dashed rectangle.

[0200] At least an indicating portion 36 of the filling level indicator 35, in particular an outside facing sidewall portion of the filling level indicator 35 is visually discernible or is visible from outside the housing 90. For this, the housing 90, in particular the body 10, e.g. also representing the second member, comprises an elongated aperture 91 as illustrated in FIGS. 4-8. The elongated aperture 91 comprises a longitudinal elongation that is identical or that substantially matches with the longitudinal elongation between the first stop 32 and the second stop 33 of the dose setting member 30. In this way the longitudinal position of the filling level indicator 35 from the start position 100 towards the end position 102 is always and/or entirely visible. The elongated aperture 91 may be covered or closed by a transparent window 92 as indicated in FIG. 8. In this way, the interior of the body 10 or housing 90 is substantially protected against ingress of humidity and/or particles.

[0201] Outside and circumferentially or tangentially offset from the elongated aperture 91 the housing 90 or body 10 comprises at least one or several radial recesses 99 configured to engage with correspondingly shaped radial protrusions 39 of the filling level indicator 35. Here, the radial protrusions 39 extend radially outwardly from an outside surface of the filling level indicator 35. The correspondingly shaped recesses 99 are provided on an inside facing portion of the sidewall of the body 10 or housing 90. An inside of the filling level indicator 35 is provided with a threaded section 38 that is in threaded engagement with an outer counter threaded section 31 of the dose setting member 30.

[0202] The recesses 99 provide a sliding track for the filling level indicator 35. The splined engagement of the protrusions 39 with the recesses 99 rotationally locks the filling level indicator 35 to the body 10 or housing 90 thereby enabling a longitudinal sliding movement of the filling level indicator 35 relative to the body 10 in longitudinal direction. A longitudinal sliding displacement of the filling level indicator 35 relative to the body 10 is induced by a rotation of the dose setting member 30 relative to the body 10. Here, the degree of rotation of the dose setting member 30 directly matches with the size of a dose.

[0203] On an outside surface of the filling level indicator 35 there is provided an indicating portion 36. The indicating portion 36 is that portion of the filling level indicator 35 that is visible from outside the housing 90.

[0204] The filling level indicator 35 further comprises a base portion 34. The base portion 34 is that part of the filling level indicator 35 that is mechanically engaged with the dose setting member 30 and with the housing 90 or body 10.

[0205] On the outside surface of the housing 90 or body 10 and along the longitudinal elongation of the longitudinal aperture 91 there is provided a scale 94 provided with numerous marks, text, symbols or numbers that help to indicate the residual amount of medicament provided in the cartridge, when the filling level indicator 35 is located adjacent to a respective portion of the scale 94.

[0206] In the configuration as illustrated in FIGS. 4 and 6 the injection device 1 and the drive mechanism 8 are in an initial configuration. The piston rod 20 is in a proximal start position and the amount of medicament inside the cartridge substantially equals the initial filling amount. In this initial configuration there has not been expelled a dose of medicament from the cartridge 6 yet. Accordingly, the filling level indicator 35 is located at or near a first longitudinal end 93 of the elongated aperture 91 thus indicating that the initial filling volume of the cartridge is still available.

[0207] As a dose of the medicament is set by rotating the dose setting member 30 relative to the housing 90 the filling level indicator 35 becomes subject to a sliding motion along the elongated aperture 91 towards was the end position 102 as indicated in FIG. 6. The amount of longitudinal displacement is indicated by a pointer 37 of the indicating portion 36 that point towards a particular marker and/or indication of the scale 94 as indicated in FIG. 7.

[0208] As the dose has been set and as the filling level indicator 35 has been moved towards the end position 102 the piston rod 20 is still positionally locked to the housing 90 or body 10. It is only during a subsequent dose dispensing or dose expelling procedure that the piston rod 20 is advanced in distal direction relative to the barrel 25 of the cartridge 6 thereby expelling a respective amount of medicament from the cartridge, typically through the injection needle 15 penetrating a piece of an injection site of a patient.

[0209] In the intermediate position 101 of the filling level indicator 35 as indicated in FIGS. 5 and 7 the filling level indicator 35 is separated in longitudinal direction from both, the first stop 32 and the second stop 33. The distance to the second stop 33 and hence the distance between the indicating portion 36 and the second longitudinal end 95 of the longitudinal aperture 91 is indicative of the residual amount of medicament that is still available in the cartridge 6. The patient or user of the device is immediately aware of the residual content of the cartridge without being obliged to detach or to remove the protective cap 18 from the cartridge holder 14 to visually inspect the medicament in the cartridge.

[0210] In this way and since the filling level indicator 35 is immediately indicative of the remaining filling level of the cartridge the cartridge holder 14 can be made of an opaque material and the medicament located inside the cartridge 6 can be enclosed by a non-transparent and hence opaque cartridge holder. The medicament located inside the cartridge 6 can be protected against electromagnetic radiation when assembled inside the injection device 1 and when received in the cartridge holder 14.

[0211] In the further example as illustrated in FIGS. 9 and 10 the filling level indicator 135 also comprises an inner threaded section 138 that is in threaded engagement with the threaded section 31 of the dose setting member 30. Also here, radial protrusions 139 of the filling level indicator 135 are in a sliding engagement with the housing 90 or body 10 of the injection device 1. Also here, the filling level indicator 135 comprises a base portion 134 that is mechanically engaged with both, the housing 90 and the dose setting member 30. Different to the example as described above in connection with FIGS. 4, 5 and 8 the filling level indicator 135 comprises an indicating portion 142 located outside the housing 90 or located outside the body 10.

[0212] Here, the filling level indicator 135 comprises a L-shaped rod 140 comprising the indicating portion 142 and a bridging portion 141. The bridging portion 141 is connected to or integrally formed with a longitudinal end of the elongated indicating portion 142. It is also connected to or integrally formed with the base portion 134 of the filling level indicator 135. The bridging portion 141 extends through the elongated aperture 91 in the housing 90 or body 10. In this way the bridging portion 141 is in a longitudinally splined or sliding engagement with the housing 90 or body 10. It is hence rotationally locked to the housing 90 or body 10 through the bridging portion 141. The tangential width of the bridging portion 141 may substantially match or correspond to the tangential size of the elongated aperture 91. In this way, a substantially slack free sliding engagement between the housing 90 or body 10 with the filling level indicator 135 can be provided.

[0213] With this example the further protrusions 139 of the filling level indicator 135 may become superfluous. Insofar, the filling level indicator 135 may be implemented also without the radially outwardly extending protrusions 139. Accordingly, also the housing 90 or body 10 may be void of the elongated recessed 99. A longitudinal sliding engagement between the housing 90 and the filling level indicator 135 may be exclusively provided and obtained by the bridging portion 141 extending through the elongated aperture 91 of the housing.

[0214] The bridging portion 141 further comprises at least one stop face 144 facing towards the end position 102 and hence facing towards the second longitudinal end 95 of the elongated aperture 91. When approaching the end position 102 the stop surface 144 may abut with the second longitudinal end 95 of the elongated aperture 91 thereby impeding any further displacement of the filling level indicator 135 beyond the end position 102.

[0215] Due to the threaded engagement between the filling level indicator 135 and the dose setting member 30 a further dose incrementing rotation of the dose setting member for setting of a dose that would exceed the amount of medicament left in the cartridge 6 can be effectively prevented.

[0216] Insofar, the filling level indicator 135 fulfills a twofold function. On the one hand the filling level indicator 135 visually illustrates the residual amount of medicament provided in the cartridge 6. On the other hand the filling level indicator 135 provides an end stop preventing dialing or setting of a dose exceeding the residual amount of medicament provided in the cartridge.

[0217] With the example of FIGS. 9 and 10 the elongated aperture 91 of the housing 90 is void of a covering window 92. Rather, a respective portion of the housing 90 may be encapsulated or provided with an outer housing 150 as illustrated in FIG. 9. The outer housing 150 at least covers the aperture 91. The outer housing 150 also covers at least a portion or the entirety of the rod-shaped and elongated indicating portion 142 of the filling level indicator 135. The outer housing 150 may cover the entirety of the L-shaped rod 140 in longitudinal direction and in any available position of the filling level indicator 135 relative to the housing 90 or body 10.

[0218] The outer housing 150 may further comprise a transparent portion 152. The transparent portion 152 may comprise a transparent window in the outer housing 150. The entirety of the elongated indicating portion 142 or only a portion thereof may be discernible in the transparent portion 152 of the outer housing 150. One of the indicating portion 142 and the transparent portion 152 is or may be provided with a scale whereas the other one of the indicating portion 142 and the transparent portion 152 is provided with a pointer pointing towards the scale.

[0219] The outer housing 150 may be opaque at least in a region in which it covers the elongated aperture 91 of the housing 90 or body 10. In this way, the internal structure or the interior of the dose setting mechanism 9 and/or of drive mechanism 8 can remain covered and invisible from the outside of the housing 90 or outer housing 150.

LIST OF REFERENCE NUMBERS

[0220] 1 injection device [0221] 2 distal direction [0222] 3 proximal direction [0223] 4 dose incrementing direction [0224] 5 dose decrementing direction [0225] 6 cartridge [0226] 7 bung [0227] 8 drive mechanism [0228] 9 dose setting mechanism [0229] 10 second member [0230] 11 trigger [0231] 12 dose dial [0232] 13 dosage window [0233] 14 cartridge holder [0234] 15 injection needle [0235] 16 inner needle cap [0236] 17 outer needle cap [0237] 18 protective cap [0238] 19 protrusion [0239] 20 piston rod [0240] 21 bearing [0241] 22 first thread [0242] 23 pressure foot [0243] 24 second thread [0244] 25 barrel [0245] 26 seal [0246] 28 threaded socket [0247] 29 stop feature [0248] 30 first member [0249] 31 threaded section [0250] 32 stop [0251] 33 stop [0252] 34 base portion [0253] 35 filling level indicator [0254] 36 indicating portion [0255] 37 pointer [0256] 38 threaded section [0257] 39 protrusion [0258] 40 spring [0259] 50 dose tracker [0260] 51 tracking stop feature [0261] 60 clutch [0262] 62 insert piece [0263] 64 stem [0264] 80 number sleeve [0265] 81 groove [0266] 90 housing [0267] 91 aperture [0268] 92 window [0269] 93 longitudinal end [0270] 94 scale [0271] 95 longitudinal end [0272] 99 recess [0273] 100 start position [0274] 101 intermediate position [0275] 102 end position [0276] 134 base portion [0277] 135 filling level indicator [0278] 138 threaded section [0279] 139 protrusion [0280] 140 rod [0281] 141 bridging portion [0282] 142 indicating portion [0283] 144 stop face [0284] 150 outer housing [0285] 152 transparent portion