End-of-life lockout mechanisms for inhalers

Abstract

An end-of-life lockout mechanism for an inhaler (100, 200, 300, 400) comprises a first housing (101a, 201a, 301a, 401a), a second housing (101b, 201b, 301b, 401b), a counting ring (106, 206, 306, 406), and a clip (112, 212, 312, 312-1, 412), the first and second housings and counting ring configured to rotate relative to one another around a common central axis, the counting ring and first and second housings configured so that each time the first and second housings are rotated relative to one another the counting ring rotates incrementally around the central axis in a forwards direction towards a zero dose position, the clip comprising a locking element (112d, 212d, 312d, 412d), the locking element configured to engage with the second housing at the zero dose position to prevent rotation relative to the first housing, the clip and counting ring further mutually configured so that once the zero-dose position is reached, rotation of the counting ring can still take place in the forwards direction over at least a limited arc.

Description

[0001] END-OF-LIFE LOCKOUT MECHANISMS FOR INHALERS

[0002] TECHNICAL FIELD

[0003] This invention relates to end-of-life lockout mechanisms for inhalers. In particular, though not exclusively, this invention relates to end-of-life lockout mechanisms for soft mist inhalers. This invention also relates to inhalers having an end-of-life lockout mechanism.

[0004] BACKGROUND

[0005] Inhalers such as soft mist inhalers (SMIs) use a cartridge or container as the source of the medicament that they deliver. In this type of inhaler, the cartridge contains a volume of medicament for delivery to a user via discrete doses that comprise a portion of the total volume within the cartridge. In use, the cartridge is located within an inhaler assembly that includes a micropump. Delivery of the medicament from the cartridge is achieved by using the micropump, which is normally manually operated / activated by the user. Although reusable inhaler assemblies are known where the cartridge can be removed and replaced once expired, it is more normal for both the inhaler and the cartridge to be disposed of after use, at end-of-life. In use, the inhaler is operated to release a discrete dose of medicament from the cartridge, with the micropump within the inhaler used to deliver the medicament dose from the cartridge.

[0006] It is important that a precise and known dose of medicament is delivered each time the inhaler is operated. However, the amount of medicament within the cartridge decreases with each delivered dose. This can lead to a situation where the amount of medicament remaining in the cartridge has dropped below the level necessary to deliver a full dose for any single operation of the inhaler, but is still sufficient to allow the appearance (but not actuality) of successful operation of the inhaler and successful delivery of a full dose. Alternatively or as well as this, operation of the micropump with a cartridge at or towards the end of life can lead to the appearance (but not actuality) of successful delivery of a full dose. Alternatively, it is possible that an over- or underconcentrated dose of medicament could be delivered if use is continued beyond the stated / design limit.

[0007] Regulators of medicines can frequently require that some method of dose indication is included in this type of inhaler, and many inhalers contain a mechanism such as a dose counter that provides a precise count of the number of doses remaining, or a dose indicator which provides an indication of the proportion of doses remaining. These counters index or ‘count’ each time the inhaler is used and the intention is that when the remaining dose count reaches zero, a user will know to replace the cartridge with a fresh, fully pressurised cartridge (either by replacing the cartridge, or replacing the entire inhaler). Examples of this type of device are described and shown in US10,929,742, US11 ,544,520, US11 ,369,760, and W02022 / 002993.

[0008] However, it is often still possible for a user to operate the inhaler even after a zero dose count has been reached. If a user attempts to use the inhaler after a zero dose count has been reached, this can result in issues such as those outlined above.

[0009] There therefore remains a need for a mechanism that can help to overcome the aforementioned drawbacks, or which at least provides the public with a useful choice.

[0010] SUMMARY OF THE INVENTION

[0011] It is an object of the present invention to provide an end-of-life lockout mechanism for inhalers which goes some way to overcoming the abovementioned disadvantages or which at least provides the public or industry with a useful choice.

[0012] It is a further object of the present invention to provide an inhaler device having an end-of-life lockout mechanism which goes some way to overcoming the abovementioned disadvantages or which at least provides the public or industry with a useful choice.

[0013] Accordingly, in a first aspect the present invention may broadly be said to consist in an end-of- life lockout mechanism for an inhaler, comprising: a first housing; a second housing; a counting ring; the first and second housings configured to connect such that the housings rotate relative to one another around a common central axis; the first and second housings and counting ring further configured and connected so that each time the first and second housings are rotated relative to one another the counting ring rotates incrementally around the central axis in a forwards direction towards a zero dose position; the mechanism further comprising a clip configured to engage with the second housing at the zero dose position to prevent rotation relative to the first housing; the clip and counting ring further mutually configured so that once the zero-dose position is reached, rotation of the counting ring can still take place in the forwards direction over at least a limited arc.

[0014] In an embodiment, the counting ring comprises a plurality of teeth around the circumference of the counting ring except for a non-toothed section that extends over an arc of the circumference of the ring, the teeth configured to engage with a gear that forms part of the inhaler so that rotation of the gear causes rotation of the ring, the non-toothed section configured and located so that at the zero-dose position the ring disengages from the gear and can rotate freely over the length of the arc.

[0015] In an embodiment, the clip comprises a spring arm, the second housing comprising a second housing abutment configured to receive and engage with the end of the spring arm at the zerodose position so as to prevent rotation of the second housing.

[0016] In an embodiment, the counting ring is configured to hold the spring arm away from engagement with the second housing abutment until the zero-dose position.

[0017] In an embodiment, the clip comprises a split ring having one end formed as a spring arm, the spring arm bent at an angle out of the plane of the ring.

[0018] In an embodiment, the locking element and counting ring are mutually configured to engage at the zero dose position to prevent rotation of the counting ring in a rearwards direction.

[0019] In an embodiment, the counting ring comprises a notch configured to receive the spring arm, the notch having a front wall configured so that when the front wall and spring arm are in contact, rotation of the counting ring in a rearwards direction is prevented.

[0020] In an embodiment, the front wall is aligned substantially perpendicular to the plane of rotation of the counting ring.

[0021] In an embodiment, the rear wall of the notch is configured to allow the spring arm to freely enter and leave the notch as the counting ring rotates.

[0022] In an embodiment, the rear wall is sloped at an angle to the plane of rotation of the counting ring.

[0023] In an embodiment, the clip comprises a split ring having one end formed as a spring arm, the spring arm bent at an angle out of the plane of the ring to form an outer angled portion, and the counting ring comprises a ledge, the ledge extending inwardly from the perimeter of the ring around substantially the whole of the perimeter of the ring except for a gap formed in the ledge, the gap configured to receive the outer angled portion so that the end of the spring arm can pass through the ring to engage with the second housing at the zero-dose position.

[0024] In an embodiment, the outer angled portion comprises an elongate cut-out notch on the outer side of the ring, the notch configured to align with the ledge so that the ledge can travel within the notch as the counting ring rotates.

[0025] In an embodiment, the counting ring comprises a groove formed in a surface or edge of the counting ring, the groove running round substantially the entirety of the surface / edge of the counting ring, the groove further comprising a triggering section configured to allow travel off the groove and into the area bounded by the perimeter of the counting ring.

[0026] In an embodiment, the counting ring comprises an inwardly-extending ledge on the surface / edge of the counting ring, the triggering section comprising a cut-out in the inner wall of the groove and a cut-out in the ledge at the same location, the groove formed so the direction of the groove is angled slightly inwards at the triggering section.

[0027] In an embodiment, the clip comprises a body having one end formed as a spring arm, the spring arm comprising an outer / free end configured as a groove riding element to in use locate into a run within the groove on the edge / surface of the counting ring, the spring arm held in tension in use when the groove riding element is located in the groove.

[0028] In an embodiment, the clip and second housing are configured to engage via a male and female interference fit.

[0029] In an embodiment, the counting ring comprises a notch configured to receive at least part of the clip so that at the zero dose position at least part of the clip can pass into and through the notch to engage with the second housing. In an embodiment, the clip comprises a unitary item having a main body configured to allow the clip to be rigidly connected to the inhaler housing so that the clip 412 does not move relative to the housing, and a free end configured to pass into and through the notch to engage with the second housing.

[0030] With respect to the above description then, it is to be realised that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention.

[0031] This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.

[0032] Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.

[0033] BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Further aspects of the invention will become apparent from the following description which is given by way of example only and with reference to the accompanying drawings which show an embodiment of the device by way of example, and in which:

[0035] Figure 1 shows a cutaway side view of a known, prior art inhaler from Anovent Pharmaceutical that is typical of a known type of soft mist inhaler, the figure showing internal detail of a housing that encloses a cartridge, the housing formed from an upper housing and a lower or base housing, the upper housing comprising a mouthpiece for a user.

[0036] Figure 2 shows a side view of a type of known prior art soft mist inhaler from Merxin, the inhaler comprising a housing comprising an upper housing and a base or lower housing, the upper housing and lower / base housing in use enclosing a cartridge, the upper housing comprising a mouthpiece, a dose-release button located on the upper housing and a lid hingedly connected to the upper housing at one side, the lid shown open, the base and lid shown partly transparent so that elements enclosed by the lid and base can be seen.

[0037] Figure 3 shows a perspective view from above and to one side of the prior art inhaler of figure 2, the lid shown in the closed position, a dose counter shown on the side of the upper housing, the base and lid shown partly transparent so that elements enclosed by the lid and base can be seen.

[0038] Figure 4 shows a perspective side view of the prior art inhaler of figures 2 and 3 with the lid shown partly open.

[0039] Figure 5 shows a cut-away side view of the prior art inhaler of figures 2 to 4, the inhaler cut away on the vertical plane to show internal detail of the inhaler, the upper housing comprising a mouthpiece and nozzle assembly, the lower or base housing enclosing a spring cage that in turn encloses a cartridge, a counting ring located between the upper and lower housings.

[0040] Figure 6 shows a side view of an inhaler according to a first embodiment of the invention, part of the lower housing removed / not present, and part of the upper housing shown transparent and with the lid not present, so as to show internal detail of the inhaler, the end-of-life mechanism of the inhaler comprising a clip that interacts with a counting ring, the clip and counting ring held in position by a fastening element that forms part of the upper housing.

[0041] Figure 7 shows a perspective, partly exploded view of the inhaler of figure 6, that part of the upper housing shown in figure 6 and the fastening element shown in exploded view so as to show detail of the clip and counting ring located in the inhaler.

[0042] Figure 8 shows a perspective view from the same angle as figure 7 of the interior elements of the inhaler of figures 6 and 7 with the counting ring and clip removed and not present.

[0043] Figure 9a shows a perspective view of the interior elements of the inhaler from the same angle as figures 7 and 8, with the clip and counting ring present and shown in a position where the inhaler has been used to dispense a number of doses and there are a number of doses still left in the inhaler.

[0044] Figure 9b shows a perspective view from the same angle as figure 9a of the same elements as figure 9a, with the clip and counting ring shown in an end-of-life position.

[0045] Figure 10 shows a side view of the interior elements of the inhaler, showing detail of a worm gear that interacts with the counting ring to drive the counting ring, the counting ring shown in an end- of-life position, the worm gear located on the opposite side of the inhaler to the clip and counting ring at end-of-life.

[0046] Figure 11 shows a perspective view of the counting ring of the first embodiment.

[0047] Figures 12a and 12b show a perspective and a plan view respectively of the clip of the first embodiment.

[0048] Figures 13a and 13b show a perspective and a plan view respectively of a clip according to a second embodiment of the invention.

[0049] Figures 14a and 14b show a perspective and a plan view respectively of a counting ring according to a second embodiment of the invention. Figure 15 shows a perspective view from above of the interior elements of an inhaler according to a second embodiment, the inhaler fitted with the clip and counting ring of figures 13 and 14, the clip and counting ring shown in an end-of-life position.

[0050] Figure 16 shows a perspective view from above and from a different angle to figure 15 of the interior elements of an inhaler according to a second embodiment, the inhaler fitted with the clip and counting ring of figures 13 and 14, the clip and counting ring shown in an end-of-life position.

[0051] Figure 17 shows a cutaway side view of part of the upper housing, spring cage, counting ring, and clip of the second embodiment.

[0052] Figure 18 shows a close-up perspective view of the internal elements of the inhaler for a third embodiment of the invention located in an inhaler and ready for use, showing detail of a clip and counting ring according to the third embodiment.

[0053] Figure 19 shows a close-up perspective view from above of the internal elements of the inhaler for the third embodiment, located in an inhaler and ready for use, the figure showing in particular a clip and counting ring according to a third embodiment.

[0054] Figure 20 shows a close-up perspective view from above of the internal elements of the inhaler from a different angle than figure 19, and with the clip and counting ring at the end-of-life position.

[0055] Figure 21 shows a close-up perspective view from above of the clip and counting ring of the third embodiment at the end-of-life position, from a different angle than figure 20.

[0056] Figures 22a - 22d show perspective view from different angles of the counting ring of the third embodiment.

[0057] Figures 23a and 23b show perspective views from different angles of the clip of the third embodiment.

[0058] Figure 24 shows a perspective view from above of a variation of the clip of the third embodiment.

[0059] Figure 25 shows an exploded perspective view of an inhaler according to a fourth embodiment of the invention.

[0060] Figure 26 shows an exploded perspective view of an inhaler according to a fourth embodiment of the invention from the same angle as figure 25, with part of the upper housing removed so as to show detail of the internal elements of the inhaler, the figure showing in particular a clip and counting ring according to a third embodiment.

[0061] Figure 27 shows

[0062] Figure 28 shows a perspective view of the inhaler of figures 25 to 27 with part of the upper housing removed so as to show internal detail of the inhaler.

[0063] Figures 29a and 29b show perspective views from different angles of the counting ring according to the fourth embodiment of the invention, the counting ring having a notch in the lower side of the counting ring.

[0064] Figure 30 shows a perspective view of the clip according to the fourth embodiment of the invention.

[0065] Figure 31 shows a perspective side view of the inhaler in use, with part of the upper housing removed so as to show detail of the counting ring and clip, the clip and counting ring shown at a position at or close to the start of the life of the inhaler with multiple doses remaining, the clip moving over the outer surface of the counting ring.

[0066] Figure 32 shows a perspective side view of the inhaler in use, with part of the upper housing removed so as to show detail of the counting ring and clip, the clip and counting ring shown at the end-of-life position with the clip engaging with the notch in the counting ring.

[0067] Figure 33 shows

[0068] DETAILED DESCRIPTION

[0069] General

[0070] In all of the embodiments of the invention described below, the inhalers have certain common elements, both with known, prior art types of inhalers, and with one another. A known, prior art type of inhaler is shown in figures 2 to 5. This has the following basic or standard elements: a housing 1 formed so as to have an upper or first housing 1 a, and a lower housing 1 b; a mouthpiece 2 that forms part of the upper housing 1a; a cartridge 3; a spring 4; a spring cage 5 that forms part of the lower housing 1b; a counting ring 6, a button 7, and; a lid 8. The inhaler is configured to act as a micropump that operates in use to deliver a dose of medicament from the cartridge to the mouthpiece. The upper housing 1a, and the lower housing 1 b, do not have to be unitary items, and can each be formed as an assembly, from multiple pieces.

[0071] The cartridge 3 is contained within the housing 1 , and is fluid ical ly connected internally within the housing to the mouthpiece 2 so that in use doses of medicament can travel from the cartridge 3 to the mouthpiece for inhalation by a user when the inhaler is activated - that is, by a user pressing the button 7.

[0072] The inhaler is operated by twisting the upper and lower housings 1a, 1 b of the housing 1 relative to one another to ‘cock’ the mechanism and prime the micropump. This action causes the counting ring 6 to incrementally rotate, and to index once (that is, to rotate sufficiently so as to count one dose). A user then presses the button 7 to release a dose of medicament via the mouthpiece.

[0073] The inhalers of the present invention contain the same common elements as described above, plus an end-of-life mechanism. The lockout mechanism / end-of-life mechanism is configured so that after a set number of uses, the end-of-life mechanism activates to prevent further use of the inhaler, as described in detail below for the specific embodiments. Similar numbering is used for all of the common elements in the specific embodiments of the invention described below, this numbering based on the general numbering outlined above - e.g. in the first embodiment the upper / first and lower / second housings are numbered 101a, 101b, the mouthpiece is numbered 102, the counting ring 106 etc. In the second embodiment the upper and lower housings are numbered 201a, 201 b, the mouthpiece is numbered 202, the counting ring 206 etc.

[0074] Where directional signifiers such as ‘vertical’ or ‘horizontal’ are used, these have their normal meaning. However, when these are used with reference to the inhaler or any part thereof, this should be taken to mean ‘with the inhaler standing upright on a flat substantially horizontal surface’, and with the mouthpiece pointing upwards vertically.

[0075] First Embodiment

[0076] A first embodiment of an end-of-life lockout mechanism according to the invention, and an inhaler fitted with the end-of-life mechanism, is shown in figures 6 to 12.

[0077] An inhaler 100 with the lower housing and lid removed or not shown is shown in figure 6. The inhaler 100 is substantially similar to the known type of inhaler 1 , with differences to accommodate the end-of-life mechanism as outlined below.

[0078] In this embodiment, the mouthpiece 102 forms part of the upper housing 101a, and the upper housing 101a also has an attachment hinge at one side for a lid (similar to that shown in figure 2).

[0079] The housing 101 encloses the internal elements of the inhaler such as the cartridge (not shown for this embodiment), counting ring 106, and a clip 112 that forms part of the end-of-life lockout mechanism. The spring cage 105 can be taken to form part of the lower housing assembly 101b, or to be connected to the lower housing 101 b.

[0080] The counting ring 106 comprises a ring-shaped element - circular in plan view - located so as to extend around the upper part of the spring cage 105 inside the upper housing 101a. The counting ring 106 is located towards the lower end of the upper housing 101 a. The counting ring 106 is described in detail below.

[0081] A central connector ring 116 is located below the counting ring 116, the central connector forming part of the upper housing 101a. The counting ring 106 rotates on top of the central connector ring 116 in use.

[0082] As shown in figure 8, the spring cage 105 comprises a helical thread 109 running around the outer surface. A stop portion or abutment 110 is formed extending upwards from the upper surface of the helical thread approximately halfway along the length of the helical thread.

[0083] A clip 112 locates onto the top of the counting ring 106, the clip 112 circular in plan view and having substantially the same radius and horizontal thickness as the counting ring 106. The clip 112 is described in detail below. The counting ring 106 and clip 112 are held in position by a fastening element 113 that comprises a circular main body 113a and connecting arms 113b at each side (diametrically opposed) of the main body 113a, the fastening element 113 locating over the top of the clip 112 to sandwich the clip 112 and counting ring 106 between the underside of the fastening element 113 and the central connector 116, the connecting arms 113b connecting to the central connector 116.

[0084] The clip 112, the spring cage 105, the central connector ring 116, the fastening element 113, and counting ring 106 are arranged concentrically at the point / height in the inhaler where the counting ring 106 is located, with the clip 112, the spring cage 105, central connector 116, and counting ring 106 having a common central axis.

[0085] The counting ring 106, clip 112, and fastening element 113 are held together so that the counting ring 106 can rotate about the common central axis relative to the clip 112, with the fastening element 113 and clip 112 held in position (not rotating) relative to the upper housing 101a. Fastening element 113 connects to the central connector 116, and fastening element 113 and the central connector 116 can also be considered to be part of the assembly that forms upper housing 101a.

[0086] Counting Ring - First Embodiment

[0087] The counting ring 106 in this embodiment has a toothed lower edge or surface, with teeth 106a formed in the lower surface / edge. A wormgear 114 is located in the housing, and connects between the housing and the counting ring 106 so that the wormgear 114 interacts with the teeth 106a of the counting ring 106. The upper surface of the counting ring 106 is adapted to act as part of the lockout mechanism, as detailed below.

[0088] As noted above, in use the user ‘cocks’ or prepares the inhaler for use by twisting the upper and lower housings relative to one another, this twisting motion occurring around the common central axis of rotation, which runs substantially centrally, vertically, from the top to the bottom of the inhaler (the inhaler in this embodiment being a similar configuration to inhaler 1 of the prior art). The wormgear 114 is connected to the housing and located so that this relative rotational action drives rotation of the wormgear 114, which causes the counting ring 106 to rotate and to index once (that is, rotate around its central axis a fraction of the circumference of the ring 106, from an initial position to a second position, to make a count of ‘one dose’). This movement of the counting ring 106 takes place every time the relative rotational movement of the upper and lower housings takes place, with the counting ring 106 moving in the same direction each time, so that there is incremental rotation of the counting ring 106. In this embodiment, the counting ring 106 is marked with numbers, and a window is formed in the housing so as to allow a user to see how many doses have been used and / or are remaining.

[0089] This twisting action also primes the inhaler for delivery of the medicament from the cartridge to the mouthpiece. Once the inhaler has been prepared for use, a user then puts their mouth over the mouthpiece 102 and presses the button 107 to release a dose of medicament into their mouth via the mouthpiece.

[0090] A notch or cut-out section 111 is formed in the upper surface or edge of the counting ring 106. The notch 111 has a flat base 111a that runs parallel to the upper and lower edges of the counting ring, and a substantially vertical front wall 111 b. The rear wall 111 c of the notch 111 is angled so that there is a shallow slope between the top edge of the counting ring 106, and the base 111 a of non-toothed span or non-toothed section 115 is formed over a sector of the lower edge of the counting ring 106. The non-toothed section is as deep as the gaps that form part of the teeth 106a, the non-toothed section 115 having a length around the perimeter of the counting ring that is approximately the same as that of five or six of the teeth 106a.

[0091] Clip - First Embodiment

[0092] The end-of-life lockout mechanism in this embodiment comprises a clip 112, that has the general form of a split ring. That is, the clip 112 is circular in plan view, but with a gap or split at one point in the circle so that there are two free ends, the free ends generally adjacent to one another.

[0093] As shown in figures 12a and 12b, a short portion or section 112b of the body of the clip 112 is bent upwards towards one free end of the clip, so as to run substantially perpendicular to the main ring body 108a. A portion 112c of the ring directly next to portion 112b, further towards the free end, is bent back so as to run substantially parallel with the main ring body 112a, but above the main ring body 112a. The final portion of the ring between the free end and portion 112c is angled downwards at an angle of approximately 20 degrees to the plane of the main body portion 112a, so as to form an angled portion 112d , with the free end (the outer end of angled portion 112d) located below the plane of the main body 112a.

[0094] Use - First Embodiment

[0095] In use, as outlined above, a user operates the inhaler by twisting / rotating the two housings relative to one another to prime or ‘cock’ the inhaler, the user then pressing the button 107 to release a dose once the inhaler is primed. Pressing the button also allows the inhaler to revert back to an unprimed or ‘uncocked’ state where a user can restart the process.

[0096] Each time the inhaler is used, the counting ring 106 will rotate incrementally so as to count ‘one dose’.

[0097] During the majority of the uses of the inhaler, from fully loaded with e.g. 120 doses, down to the last few remaining doses, the outer angled portion 112d of clip 112 is bent upwards and held upwards in spring tension, so that the outer angled portion 112d rides or sweeps along the top edge or surface of the ring 106 as shown in figure 9a. Therefore, in normal use, the free end of the outer angled portion 112d will pass over the top of the abutment 110 on the spring cage 105 (part of the lower housing 101b) as the two housings are rotated relative to one another. As outlined above, the clip 112 is held in a non-moving / non-rotational relationship with the fastener 113, which is rigidly connected to connecting ring 116, the fastener 113 and connecting ring 116 forming part of the upper housing 101a.

[0098] Towards the end of life of the inhaler, with only a few doses remaining, the ring 106 has rotated sufficiently so that the free end of the outer angled portion 112d will align with the top end of the rear wall 111 c of the notch 111. Further uses of the inhaler cause the ring to rotate, and the free end of the outer angled portion 112d will start to move down the sloped rear wall 111c, with the spring tension in the arm releasing to push the arm downwards and into the notch 111. That is, the rear wall of the notch is configured to allow the spring arm to freely enter the notch as the counting ring rotates.

[0099] As the inhaler continues to be used, and reaches the final dose stage, the free end of the outer angled portion 112d is located fully within the notch, and as can be seen with reference to figure 9b, the free end contacts the abutment 110. This contact prevents further rotation of the two housings relative to one another. When a user attempts to cock the inhaler ready for use, the abutment 110 (on the spring cage 105, which forms part of the lower housing 101b) contacts the free end of the outer angled portion 112d (which is held in a rigid, non-rotational relationship with the housing assembly 101a). The spring cage 105 cannot rotate as it is blocked from doing so by the free end of the outer angled portion 112d pressing against the abutment 110. Therefore, relative rotation of the two housings 101a, 101 b is prevented, and a user cannot cock the inhaler ready for use.

[0100] The inhaler has now been locked out of use at end of life - the inhaler is effectively locked and can no longer be operated - that is, the inhaler has an end-of-life lockout mechanism, as it cannot be ‘cocked’ for further use.

[0101] At this point, as can be seen best with reference to figure 9b, the front wall 111 b of the notch 111 in the counting ring 106 is also in contact with the free end of the outer angled portion 112d. This prevents the counting ring from rotating anti-clockwise (with reference to figure 9b). However, the counting ring is not prevented from rotating clockwise - rotation in this direction would cause the free end of the outer angled portion 112d to slide along the flat base 111a and up the angled rear wall 111c. That is, the rear wall of the notch is configured to allow the spring arm to freely leave the notch as the counting ring rotates.

[0102] In this position, as can be seen with reference to figure 10, the counting ring 106 has advanced to a position where the worm gear 114 has interacted with the final tooth on the counting ring 106 before the non-toothed span or section 115, and the counting ring 106 has rotated so that the worm gear 114 is just located in the non-toothed span or section 115, at the leading edge of the non-toothed section. The counting ring 106 is therefore free to rotate clockwise without the worm gear 114 preventing this movement - the worm gear 114 does not lock the counting ring 106 in place via the teeth 106a.

[0103] Second Embodiment Second embodiments of a counting ring 206 and a clip 212 are shown in figures 13 and 14.

[0104] Counting Ring - Second Embodiment

[0105] The counting ring 206 in this embodiment is shown in figures 14a and 14b, and comprises an outer wall 206b (on which the dose numbers are marked), and an inwardly-extending ledge 206c that runs around the top edge of the vertical outer wall 206b, substantially perpendicular to the outer wall 206b. A short gap 206d is formed in the ledge 206c at one location on the circumference of the ledge 206c.

[0106] The counting ring 206 has teeth 206a on the underside of the ring 206, and a non-toothed span or section 215, substantially similar to the counting ring 106 of the first embodiment.

[0107] Clip - Second Embodiment

[0108] The clip 212 of the second embodiment is shown in figures 13a and 13b and is substantially similar to that of the first embodiment. However, in this embodiment the outer angled portion 112d comprises a shallow elongate cut-out notch 212d(i) on the outer side, as shown in figures 13a and 13b.

[0109] Use - Second Embodiment

[0110] The clip 212 and counting ring 206 are mounted in an inhaler in a substantially similar manner to that described above for the first embodiment. Use of the inhaler is substantially similar to that described above for the first embodiment, with the outer angled portion 212d of clip 212 bent upwards and held upwards in spring tension, so that the outer angled portion 212d rides or sweeps along the top edge or surface of the ring 206.

[0111] Towards the end of life of the inhaler, with only a few doses remaining, the ring 206 has rotated sufficiently so that the free end of the outer angled portion 212d will align with the short gap 206c in the ledge 206b. Further uses of the inhaler cause the ring 206 to rotate, and the free end of the outer angled portion 212d will move into the short gap 206c, with the spring tension in the arm releasing to push the arm downwards and into the short gap 206c.

[0112] As the inhaler reaches the final dose stage, the free end of the outer angled portion 212d contacts the abutment 210. This contact prevents further rotation of the two housings relative to one another. When a user attempts to cock the inhaler ready for use, the abutment 210 presses against the free end of the outer angled portion 212d, and relative rotation of the two housings is prevented, and a user cannot cock the inhaler ready for use.

[0113] The inhaler has now been locked out of use at end of life - the inhaler is effectively locked and can no longer be operated - that is, the inhaler has an end-of-life lockout mechanism, as it cannot be ‘cocked’ for further use.

[0114] At this point, as can be seen best with reference to figure 17, the free end of the outer angled portion 212d is below the level of the ledge 206c on the counting ring 206. The outer angled portion 212d is aligned at an angle in relation to the ledge 206c, with the ledge travelling inside the cut-out notch 212d(i). The counting ring 206 is therefore not prevented from rotating by the clip 212.

[0115] Similar to the first embodiment, in this position the counting ring 206 has advanced to a position where the worm gear has interacted with the final tooth on the counting ring 206 before the nontoothed span or section 215, and the counting ring 206 has rotated so that the worm gear is just located in the non-toothed section 215, at the leading edge of the non-toothed section. The counting ring is therefore free to rotate clockwise, without the worm gear 214 preventing this movement.

[0116] The inhaler has been locked out of use at end of life - the inhaler is effectively locked and can no longer be operated as the upper and lower housing assemblies can no longer rotate relative to one another. That is, the inhaler has an end-of-life lockout mechanism, as it cannot be ‘cocked’ for further use.

[0117] Third Embodiment

[0118] A third embodiment of lockout mechanism is shown in figures 18 - 24.

[0119] The inhaler 300 in this embodiment is substantially similar to the inhaler 100 of the first embodiment, with differences to accommodate the third embodiment of end-of-life mechanism as outlined below.

[0120] As for the first and second embodiments described above, the internal elements of the inhaler are contained within a housing formed from upper and lower housing parts.

[0121] A central connector ring 316, spring cage 305, and fastening element 313 are located within the housing. These elements are substantially the same as those described above for the first embodiment (central connector ring 116, spring cage 105, and fastening element 113 in the first embodiment). The spring cage 305 comprises a helical thread 309 running around the outer surface, as for the first embodiment, with a stop portion or abutment 310 extending upwards from the upper surface of the helical thread approximately halfway along the length of the helical thread.

[0122] A ring-shaped counting ring 306, circular in plan view, is located in a substantially similar position to that of the counting ring 106 of the first embodiment - towards the lower end of the upper housing 301a and extending around the upper part of a spring cage inside the upper housing 301a - the counting ring 306 rotating on top of the central connector ring 316 in use. Rotation of the counting ring 306 when the inhaler is operated is substantially similar to that of the embodiments described above, with a worm gear (not shown for this embodiment) interacting with the teeth on the lower side / edge of the counting ring 306 to drive rotation of the counting ring 306.

[0123] The counting ring 306 is held in position by a fastening element 313 that is substantially similar to the fastening element 113 of the first embodiment, the fastening element comprising a circular main body 313a and connecting arms 313b at each side (diametrically opposed) of the main body 313a. In use, the fastening element 313 locates over the top of counting ring 306 to sandwich the counting ring 306 between the underside of the fastening element 313 and the central connector 316, the connecting arms 313b connecting to the central connector 316.

[0124] As for the first embodiment, the spring cage 305, the central connector ring 316, the fastening element 313, and counting ring 306 are arranged concentrically at the point / height in the inhaler where the counting ring 306 is located, with the clip 312, the spring cage 305, central connector 316, and counting ring 306 having a common central axis. The counting ring 306 and fastening element 313 are held together so that the counting ring 306 can rotate about the common central axis, with the fastening element 313 held in position (not rotating) relative to the upper housing 301 a. Fastening element 313 connects to the central connector 316, and fastening element 313 and the central connector 316 can also be considered to be part of the assembly that forms upper housing 301a.

[0125] As shown in figure 18, a clip 312 is connected to the underside of the fastening element 313, close to one of the connecting arms 313b (that arm on the opposite side from the worm gear, in this embodiment). The fastening element 313 has a cut-out slot on the underside of the fastening element 31 , along a short length of the underside of the fastening element 313, the slot sized and shaped so that the body of the clip 312 can located fully into the slot. A short cylindrical pole 317 extends downwards into the slot from the upper surface of the slot, with the clip 312 attaching to the fastening element 313 via a circular aperture in the body of the clip 312. In use, the clip 312 is pushed onto the short cylindrical pole 317 and is held in place via an interference fit between the short cylindrical pole 317 and the circular aperture in the body of the clip 312. The aperture in the clip and the pole form a male / female connector. It should be noted that the positions of these could be reversed- that is, the pole could be on the clip and the aperture on the housing.

[0126] Clip - Third Embodiment

[0127] The clip 312 of the third embodiment is shown in detail in figures 23a and 23b. The clip 312 comprises a unitary item that has a main body formed from two substantially parallel sections 312a and 312c that are connected by a short portion or section 312b that runs substantially perpendicular to the parallel sections 312a and 312c so that the main body generally has an S- shape. An angled portion 312d extends from the end of the higher one of the sections - section 312c, the angled portion 312d forming a spring arm. The angled portion 312d is angled downwards at an angle of approximately 20 degrees to the substantially parallel sections 312a and 312c. The free end of the angled portion 312d is located below the lower one of the sections - section 312a - but in use is in contact with and pushed upwards into the slot by the upper edge of the counting ring 306, which the outer / free end of angled portion 312d is in contact with in use. When pushed upwards, the outer / free end of angled portion 312d is in spring tension. The outer / free end of the angled portion 312d is configured as a groove riding element or groove rider 312e, to in use locate into and run within a groove 311 on the upper edge / surface of the counting ring 306, as described in detail below.

[0128] As shown in figures 23a and 23b, the inner / upper one of the parallel sections - section 312c - has a circular aperture therethrough, which allows the clip 312 to be connected to the underside of the fastening element 313, within the slot, via the cylindrical pole 317.

[0129] Counting Ring - Third Embodiment

[0130] The counting ring 306 in this embodiment is shown in figures 22a - 22d. The counting ring 306 in this embodiment is generally the same as for the first embodiment, with a toothed lower edge or surface that interacts with a wormgear (not shown) that is located in the housing to in use cause the counting ring 306 to rotate. The upper surface of the counting ring 306 is adapted to act as part of the lockout mechanism, as detailed below.

[0131] The upper surface or edge of the counting ring 306 comprises an inwardly-extending ledge 306c. A groove 311 is formed in the upper surface or edge of the counting ring 306. The groove 311 is located on the top surface or edge of the ring 306, and is formed as a lower section or path in the top edge with walls on either side (inner and outer walls on the inner and outer sides of the counting ring 306). The lower or central path section of the groove 311 is located substantially in the centre of the upper edge. As shown in figure 22 and in particular figure 22d, the groove 311 runs round substantially the entirety of the upper edge of the counting ring 306, with a triggering section 318 formed in the upper edge / surface at one location. The triggering section 318 comprises a cut-out in the inner wall of the groove 311 , and a cut-out in the ledge 306c at the same location. These cutouts mean that at the triggering section 318, the groove 311 opens or runs inwards into the area bounded by the perimeter of the counting ring. The path section and walls of the groove 311 are formed at this point so the direction of the groove is angled slightly inwards. In use, anything travelling in the groove 311 will reach the triggering section 318 and will then travel / run off the groove and into the area bounded by the perimeter of the counting ring 306.

[0132] The same as for the first and second embodiments, a non-toothed span or section 315 is formed over a sector of the lower edge of the counting ring 306. The cut-out sector is as deep as the gaps that form part of the teeth on the lower edge of the counting ring 306, the non-toothed span or section 315 having a length around the perimeter of the counting ring that is approximately the same as that of five or six of the teeth.

[0133] Use - Third Embodiment

[0134] As for the first and second embodiments above, in use the user ‘cocks’ or prepares the inhaler for use by twisting the upper and lower housings relative to one another, the wormgear connected to the housing and located so that this relative rotational action drives rotation of the wormgear, which causes the counting ring 306 to rotate and to index once.

[0135] This twisting action also primes the inhaler for delivery of the medicament from the cartridge to the mouthpiece. Once the inhaler has been prepared for use, a user then puts their mouth over a mouthpiece and presses a button to release a dose of medicament into their mouth via the mouthpiece.

[0136] The clip 312 and counting ring 306 are mounted in an inhaler in a substantially similar manner to that described above for the first embodiment. In the third embodiment, the groove rider 312e locates into the groove 311 so that the groove rider 312e follows the groove 311 in the same way that a record player stylus will follow a groove in a vinyl record, as the ring 306 rotates.

[0137] Towards the end of life of the inhaler, with only a few doses remaining, the ring 306 has rotated sufficiently so that the groove rider 312e approaches the triggering section 318, as shown in figure 19. Further uses of the inhaler cause the ring 306 to rotate past this point, and the groove rider 312e then reaches the triggering section 318. At this point - the final dose point - the groove rider 312e moves inwards, following the inwardly angled groove, and the outer / free end of angled portion 312d moves downwards as the spring tension in the angled portion 312d is released to push the arm downwards, into and through the cut-out in the ledge 306c.

[0138] Once the outer / free end of angled portion 312d has moved downwards, and into and through the cut-out in the ledge 306c, the free / outer end of the angled portion 312d will contact the abutment 310 if any further rotation of the tow housing parts is attempted. This contact prevents further rotation of the two housings relative to one another. When a user attempts to cock the inhaler ready for use, the abutment 310 presses against the free end of angled portion 312d, preventing relative rotation of the two housings, and a user cannot cock the inhaler ready for use.

[0139] The inhaler has now been locked out of use at end of life - the inhaler is effectively locked and can no longer be operated - that is, the inhaler has an end-of-life lockout mechanism, as it cannot be ‘cocked’ for further use.

[0140] At this point, similarly to the embodiments described above, the counting ring 306 is not prevented from rotating. In this position the counting ring 306 has advanced to a position where the worm gear has interacted with the final tooth on the counting ring 306 before the non-toothed span or section 315, and the counting ring 206 has rotated so that the worm gear is just located in the non-toothed span or section at the leading edge of the non-toothed span or section 315. The counting ring is therefore free to rotate clockwise, without the worm gear preventing this movement.

[0141] The inhaler has been locked out of use at end of life - the inhaler is effectively locked and can no longer be operated as the upper and lower housing assemblies can no longer rotate relative to one another. That is, the inhaler has an end-of-life lockout mechanism, as it cannot be ‘cocked’ for further use. Third Embodiment - Variation

[0142] A variation of the third embodiment described above is shown in figure 24. In this variation, the counting ring is the same as for the third embodiment described above, with a groove on the upper surface. However, in this variation, the clip 312-1 is formed as an integral part of a split ring very similar to the split ring of the first embodiment. The clip 312-1 is as described above for the third embodiment, but is formed on the end of, and as part of, a split ring the same as or similar to that described above for the first embodiment.

[0143] Fourth Embodiment

[0144] A fourth embodiment of lockout mechanism is shown in figures 26 to 32.

[0145] The inhaler 400 in this embodiment is substantially similar to the inhaler 100 of the first embodiment, with differences to accommodate the fourth embodiment of end-of-life mechanism as outlined below.

[0146] As for the embodiments described above, the internal elements of the inhaler are contained within a housing formed from upper and lower housing parts 401 a, 401b.

[0147] A central connector ring 416, fastening element 413, and spring cage 405 are located within the housing. These elements are substantially the same as those described above for the first embodiment (central connector ring 116, fastening element 113, and spring cage 105). The spring cage 405 comprises a helical thread 409 running around the outer surface, as for the first embodiment.

[0148] A ring-shaped counting ring 406, circular in plan view, is located in a substantially similar position to that of the counting ring 106 of the first embodiment - towards the lower end of the upper housing 401a and extending around the upper part of a spring cage inside the upper housing 401a - the counting ring 406 rotating on top of the central connector ring 416 in use. Rotation of the counting ring 406 when the inhaler is operated is substantially similar to that of the embodiments described above, with a worm gear (not shown for this embodiment) interacting with the teeth on the counting ring 406 to drive rotation of the counting ring 406. In this embodiment, the counting ring 406 and the drive mechanism (worm gear, etc) are configured with the teeth formed in and extending from the top or upper edge of the ring 406.

[0149] As for the first embodiment, the spring cage 405, the central connector ring 416, and counting ring 406 are arranged concentrically at the point / height in the inhaler where the counting ring 406 is located, with the spring cage 405, central connector 416, and counting ring 406 having a common central axis. In use, the counting ring 406 is held in position by the elements surrounding the ring 406 (e.g. the central connector 416, the fastening element 413), and is held and positioned so that the counting ring 406 can rotate about the common central axis.

[0150] As shown in figure 28, a clip 412 is located so as to in use interact with the counting ring 406.

[0151] The counting ring 406 and clip 412 are described in detail below, and the operation of the inhaler (and in particular the clip 412 and counting ring 406) is also described in detail below.

[0152] Counting Ring - Fourth Embodiment

[0153] The counting ring 406 in this embodiment is shown in figures 28a and 28b. The counting ring 406 in this embodiment is similar to the rings of the previous embodiments, except that in this embodiment, the ring has a toothed upper edge or surface rather than a toothed lower surface. The toothed edge interacts with a wormgear (not shown) that is located in the housing so that in use this causes the counting ring 406 to rotate.

[0154] A non-toothed span or section 415 is formed over a sector of the upper edge of the counting ring 406. The non-toothed span or section is as deep as the gaps that form part of the teeth on the upper edge of the counting ring 406, the non-toothed span or section 415 having a length around the perimeter of the counting ring that is approximately the same as that of five or six of the teeth.

[0155] A notch 411 is formed in the lower surface or edge of the counting ring 406, close to the zerodose count marking on the outer surface of the ring 406. In use, the notch receives a free end of the clip 412 as detailed below.

[0156] Clip - Fourth Embodiment

[0157] A fourth embodiment of clip is shown in figures 29a and 29b. The clip 412 comprises a unitary item that has a main body formed from two upright sections 412b and 412c arranged at a slight angle to one another. The end of section 412b is curved back around on itself (inwards towards the central axis of the inhaler in use) to form a hook 412a at one end of the clip 412. In use, the hooked end 412a allows the clip to be connected to the housing so that the clip 412 does not move relative to the housing.

[0158] The clip 412 further comprises an angled portion 412d that extends outwards perpendicularly to the upright section 412c, from the base or lower edge of the upright section 412c.

[0159] An extension stub 412e extends upwards from the outer end of the upright section 412c. In use, when the inhaler is assembled and ready for use (and before end-of-life) the upright section 412c is in contact with the outer surface of the counting ring 406 so that it is pushed radially outwards slightly, so that it is in spring tension with respect to upright section 412b.

[0160] Use - Fourth Embodiment

[0161] In use, and as shown in figures 31 to 33, the clip 412 and counting ring 406 are located internal to the housing of the inhaler 400 so that the majority of the clip 412 is located below the counting ring 406, with the extension 412e extending upwards to press against, and in use run around, the lower part of the outer surface of the counting ring 406.

[0162] In use, the counting ring 406 rotates incrementally in substantially the same manner as outlined for the previous embodiments, from an initial starting position, towards a zero-dose position. As shown in figures 32 and 33, at the zero dose position the ring 406 has rotated to a position where the notch 411 is aligned with extension 412e. At this point, the spring tension in the clip 412 releases so that the upright section 412c and extension 412e are pushed inwards into the notch 411 , with the extension 412e moving through the counting ring 406 via the notch 411.

[0163] As shown in figure 33, a stop portion or abutment 410 is formed on the outer surface of the spring cage 405, with the spring cage 405 in this embodiment forming part of the lower housing. With reference to figure 33, the upright section 412c and extension 412e move inwards so that they are pressed against the outer surface of the spring cage 405, inside a perimeter formed by the inner surface of the counting ring 406.

[0164] When a user next attempts to cock or prime the inhaler for use, and with reference to figure 33, the spring cage rotates anti-clockwise (looking down on the inhaler from above), and the free end of the clip 412 will contact the abutment 410 so as to prevent the inhaler from being cocked for use, thereby locking out the inhaler. As the upright section 412c and extension 412e are inside the perimeter of the counting ring 406, the counting ring is still free to rotate.

[0165] Miscellaneous

[0166] It should be noted that the counter can in certain variations be reset. The outer end of the clip 112, 212, 312, 412 (the angled portion 112d, 212d, 312d, 412d) can potentially be lifted up or moved outwards, and the counting ring (106, 206, 306, 406) can be rotated so that when the outer angled portion (112d, 212d, 312d, 412d / 412e) of the clip is released it rides or sweeps along the top edge or surface of the ring (106, 206, 306, 406) in a similar manner to that shown in figure 9a and as described above for ‘normal use’. It is possible to configure the outer housing with a small aperture or pin hole (not shown) into which an elongate member can be inserted in order to achieve a reset

[0167] The embodiments described above are not intended to be reusable, but this variation potentially allows the device to be re-used by inserting a new cartridge.

[0168] It should further be noted that the core function of the end-of-life mechanism is to prevent further use of the inhaler at end-of-life. Having a mechanism that can achieve this as simply as possible with as few parts as possible is desirable, in order to avoid potential issues that come with increased complexity and number of components. For example, if three or more components are required to be brought into alignment and then lock together in order to achieve end-of-life lockout, then there is an increased risk of failure. That is, if each component has a similar likelihood of failing, and if end-of-life lockout will not be achieved if one component fails, then adding more components increases the likelihood that one (or more) will fail, and therefore the overall system will fail to operate as intended - there is an increased chance of failure of the system overall,

[0169] In the embodiments described above, the device is prevented from being primed or cocked by preventing rotation of the lower housing relative to the upper housing - the upper and lower housings are locked together. This removes the requirement for having additional features and complexity to also lock out the counting ring, as the counting ring is only driven as a consequence of the relative rotation of the housings. Therefore the arrangement described in the embodiments above assists with reducing the complexity of a device that includes a locking mechanism, and the additional control that would be required to bring three different components into alignment.

[0170] By reducing the complexity, a simpler design solution can be provided that has a lower component count and simpler manufacturing assembly process, which assists with reliability, and also assists with reducing cost. A simpler arrangement also helps to ensure that there are fewer ‘tolerance stacks’ (all interacting components in a device will fit together in use within a certain range of dimensions or within a ‘tolerance’, that can add movement or ‘play’ to the device, If multiple components interact with one another , then the tolerances can add to one another to increase the amount of movement or ‘play’ within the device even when it is nominally locked (no movement). Therefore, reducing the number of components can assist with reducing the amount of play, as there are fewer tolerance stacks).

Claims

CLAIMS1. An end-of-life lockout mechanism for an inhaler, comprising: a first housing; a second housing; a counting ring; the first and second housings configured to connect such that the housings rotate relative to one another around a common central axis; the first and second housings and counting ring further configured and connected so that each time the first and second housings are rotated relative to one another the counting ring rotates incrementally around the central axis in a forwards direction towards a zero dose position; characterised in that the mechanism further comprises a clip configured to engage with the second housing at the zero dose position to prevent rotation relative to the first housing; the clip and counting ring further mutually configured so that once the zero-dose position is reached, rotation of the counting ring can still take place in the forwards direction over at least a limited arc.

2. An end-of-life lockout mechanism as claimed in claim 1 wherein the counting ring comprises a plurality of teeth around the circumference of the counting ring except for a non-toothed section that extends over an arc of the circumference of the ring, the teeth configured to engage with a gear that forms part of the inhaler so that rotation of the gear causes rotation of the ring, the nontoothed section configured and located so that at the zero-dose position the ring disengages from the gear and can rotate freely over the length of the arc.

3. An end-of-life lockout mechanism as claimed in claim 1 or claim 2 wherein the clip comprises a spring arm, the second housing comprising a second housing abutment configured to receive and engage with the end of the spring arm at the zero-dose position so as to prevent rotation of the second housing.

4. An end-of-life lockout mechanism as claimed in claim 3 wherein the counting ring is configured to hold the spring arm away from engagement with the second housing abutment until the zero-dose position.

5. An end-of-life lockout mechanism as claimed in any one of claims 1 to 4 wherein the clip comprises a split ring having one end formed as a spring arm, the spring arm bent at an angle out of the plane of the ring.

6. An end-of-life lockout mechanism as claimed in claim 5 wherein the locking element and counting ring are mutually configured to engage at the zero dose position to prevent rotation ofthe counting ring in a rearwards direction.

7. An end-of-life lockout mechanism as claimed in claim 5 or claim 6 wherein the counting ring comprises a notch configured to receive the spring arm, the notch having a front wall configured so that when the front wall and spring arm are in contact, rotation of the counting ring in a rearwards direction is prevented.

8. An end-of-life lockout mechanism as claimed in claim 7 wherein the front wall is aligned substantially perpendicular to the plane of rotation of the counting ring.

9. An end-of-life lockout mechanism as claimed in 7 or claim 8 wherein the rear wall of the notch is configured to allow the spring arm to freely enter and leave the notch as the counting ring rotates.

10. An end-of-life lockout mechanism as claimed in claim 9 wherein the rear wall is sloped at an angle to the plane of rotation of the counting ring.

11. An end-of-life lockout mechanism as claimed in claim 3 or claim 4 wherein the clip comprises a split ring having one end formed as a spring arm, the spring arm bent at an angle out of the plane of the ring to form an outer angled portion, and the counting ring comprises a ledge, the ledge extending inwardly from the perimeter of the ring around substantially the whole of the perimeter of the ring except for a gap formed in the ledge, the gap configured to receive the outer angled portion so that the end of the spring arm can pass through the ring to engage with the second housing at the zero-dose position.

12. An end-of-life lockout mechanism as claimed in claim 11 wherein the outer angled portion comprises an elongate cut-out notch on the outer side of the ring, the notch configured to align with the ledge so that the ledge can travel within the notch as the counting ring rotates.

13. An end-of-life lockout mechanism as claimed in any one of claims 1 to 4 wherein the counting ring comprises a groove formed in a surface or edge of the counting ring, the groove running round substantially the entirety of the surface / edge of the counting ring, the groove further comprising a triggering section configured to allow travel off the groove and into the area bounded by the perimeter of the counting ring.

14. An end-of-life lockout mechanism as claimed in claim 13 wherein the counting ring comprises an inwardly-extending ledge on the surface / edge of the counting ring, the triggering section comprising a cut-out in the inner wall of the groove and a cut-out in the ledge at the same location, the groove formed so the direction of the groove is angled slightly inwards at the triggering section.

15. An end-of-life lockout mechanism as claimed in claim 13 or claim 14 wherein the clip comprises a body having one end formed as a spring arm, the spring arm comprising an outer / free end configured as a groove riding element to in use locate into a run within the groove on the edge / surface of the counting ring, the spring arm held in tension in use when the grooveriding element is located in the groove.

16. An end-of-life lockout mechanism as claimed in claim 15 wherein the clip and second housing are configured to engage via a male and female interference fit.

17. An end-of-life lockout mechanism as claimed in any one of claims 1 to 4 wherein the counting ring comprises a notch configured to receive at least part of the clip so that at the zero dose position at least part of the clip can pass into and through the notch to engage with the second housing.

18. An end-of-life lockout mechanism as claimed in claim 17 wherein the clip comprises a unitary item having a main body configured to allow the clip to be rigidly connected to the inhaler housing so that the clip 412 does not move relative to the housing, and a free end configured to pass into and through the notch to engage with the second housing.

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