Abstract
An inhaler for delivery of a medicament by inhalation is disclosed. The inhaler comprises a dose counting mechanism comprising a counter. The inhaler further comprises a dispensing mechanism, the dispensing mechanism being configured, on actuation, to dispense a dose of medicament and to adjust the counter. The inhaler further comprises a resetting member configured for movement in a first direction between a first position and a second position to reset the dispensing mechanism, and a prevention mechanism comprising a pair of first and second engaging members. If the movement of the resetting member in the first direction is reversed before it reaches the second position, the first and second engaging members prevent further actuation of the dispensing mechanism until the resetting member is again moved in the first direction. At least one of the first and second engaging members is configured to resiliently flex, under load, into abutment with a substantially rigid component of the inhaler. Preferably the dose counting mechanism counter indicates the number of remaining doses in, or the number of dispensed doses from, the inhaler.
Claims
1. An inhaler for delivery of a medicament by inhalation, comprising: a dose counting mechanism including a counter; a canister containing a medicament; a dispensing mechanism that is configured, when actuated, to dispense a dose of medicament and to adjust the counter of the dose counting mechanism, wherein the dispensing mechanism includes a spring for applying compressive force to the canister and a releasable locking arrangement for locking the dispensing mechanism and preventing actuation thereof; cap that pivots about an axis between a first position to and a second position to load the spring and reset the dispensing mechanism; and a prevention mechanism including at least a first engaging member and a second engaging member, wherein the first engaging member is configured to engage in a mating configuration with the second engaging member, wherein: when movement of the cap in a first direction is interrupted before the cap reaches the second position, the first engaging member engages the second engaging member and holds the load of the spring, thereby preventing actuation of the dispensing mechanism until the cap is moved again in the first direction, and at least one of the first engaging member and the second engaging member is configured to flex, under the load of the spring, into abutment with a substantially rigid component of the inhaler and the first engaging member and the second engaging member are configured to disengage from each other when subjected to a compressive motion or force.
2. The inhaler of claim 1, wherein the medicament includes an active pharmaceutical ingredient and a propellant.
3. The inhaler of claim 2, wherein the medicament includes a corticosteroid and a beta2-adrenoceptor agonist and the propellant includes at least one of HFA 227 (1,1,1,2,3,3,3-heptafluoropropane) or HFA 134a (1,1,1,2-tetrafluoroethane).
4. (canceled)
5. (canceled)
6. The inhaler of claim 1, wherein the releasable locking arrangement includes a lock member for locking a lever arm to prevent movement of the lever arm, and wherein the releasable locking arrangement includes a latch mechanism having a drop link for holding the lock member in position.
7. The inhaler of claim 6, further comprising a breath actuation mechanism an actuation button, wherein the breath actuation mechanism and the actuation button are configured to release the releasable locking arrangement thereby enabling actuation of the dispensing mechanism.
8. The inhaler of claim 7, wherein the breath actuation mechanism includes a breath-triggered pivotable vane.
9. The inhaler of claim 1, further comprising a mouthpiece, and wherein the cap covers the mouthpiece of the inhaler when the cap is in the second position.
10. The inhaler of claim 9, wherein the cap does not cover the mouthpiece when the resetting member is in the first position, and wherein the cap is configured to lock or snap in place when the resetting member is in the first position.
11. The inhaler of claim 10, wherein the dispensing mechanism further comprises a yoke, wherein the cap is configured such that rotation of the cap causes translational movement of the yoke to load the spring and to reset the dispensing mechanism.
12. The inhaler of claim 2, wherein the canister is configured to contain a plurality of doses of the medicament, and wherein the counter of the dose counting mechanism indicates how many doses of the medicament are in the canister and the counter is updated each time a dose is dispensed.
13. The inhaler of claim 1, wherein the inhaler is configured such that the counter of the dose counting mechanism is actuated at substantially the same time as a dose of medicament is dispensed.
14. The inhaler of claim 1, wherein one of the first engaging member and the second engaging member has a female engaging portion including at least one of a slot or recess and the respective other of the first engaging member and the second engaging member has a male engaging portion including at least one of a tooth or a hook, wherein the female engaging portion is configured to receive the male engaging portion.
15. (canceled)
16. (canceled)
17. The inhaler of claim 1, wherein at least one of the first engaging member and the second engaging member is deflectable or flexibly moveable relative to the other of the first engaging member and the second engaging member.
18. The inhaler of claim 17, wherein at least a portion of one and preferably both of the first engaging member and the second engaging member includes a sloped deflecting edge for aiding deflection.
19. The inhaler of claim 1, wherein at least one of the first engaging member and the second engaging member is included as part of another component of the inhaler.
20. The inhaler of claim 19, wherein the first engaging member is formed integrally with a lever of a releasable locking arrangement and the second engaging member is formed integrally with a chassis of the inhaler.
21. The inhaler of claim 2 wherein: the dispensing mechanism is configured to dispense a dose of medicament in a fire position and to be reset, for further dispensing, in a dispensing reset position; the dose counting mechanism is configured to count a dose in a counting position and to be reset, for further counting, in a counter reset position; the canister comprises a metering valve, the metering valve being configured to dispense medicament upon actuation and to refill with medicament in a refill position; when actuated, the inhaler passes through the fire position and the counting position, and after actuation, movement of the cap from a first location to a second location causes the inhaler to pass through the refill position, then the counter reset position, then the dispensing reset position; and if movement of the cap is altered after the inhaler has passed the refill position but before it has reached the dispensing reset position, the prevention mechanism engages to prevent actuation of the inhaler, and once engaged, the prevention mechanism is configured to disengage in response to further movement of the cap towards the second location.
22.-26. (canceled)
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0115] Preferred aspects and embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:
[0116] FIG. 1 is a front side perspective view of an inhaler in accordance with the present invention with the cap closed;
[0117] FIG. 2 is a schematic side view of some internal components of an inhaler in accordance with the present invention with the cap closed;
[0118] FIG. 3 is a schematic side view of the inhaler components of FIG. 2 with the cap open and the dispensing mechanism loaded and ready to dispense a dose;
[0119] FIG. 4 is a schematic side view of the inhaler components of FIG. 2 with the cap open and the dispensing mechanism unloaded having dispensed a dose;
[0120] FIG. 5 is an exploded schematic view of the components of the inhaler of FIG. 1, which has the components shown in FIGS. 2 to 4;
[0121] FIG. 6 is a schematic side view of the inhaler of FIG. 2;
[0122] FIG. 7 is a schematic side view of the inhaler of FIG. 3;
[0123] FIG. 8 is a schematic side view of the inhaler of FIG. 4;
[0124] FIG. 9 is a perspective front side view of a chassis of an inhaler in accordance with the present invention;
[0125] FIG. 10 is a close up view of the top portion of the chassis of FIG. 9, showing a component of the prevention mechanism;
[0126] FIG. 11 is a perspective side view of a lever of a releasable locking arrangement of an inhaler in accordance with the present invention;
[0127] FIG. 12 is a perspective front side view of the lever of FIG. 11 and a lever lock of the releasable locking arrangement;
[0128] FIG. 13 is a perspective front side view of the lever of FIG. 11 in its operating position in the chassis of FIG. 9;
[0129] FIG. 14 is a perspective rear side view of the inhaler of FIG. 1 with the back housing or cover and certain other components removed to show the internal components and the cap in the closed position;
[0130] FIG. 15 is a perspective rear side view of the inhaler of FIG. 1 with the cap in the open position and the dispensing mechanism loaded and ready to dispense a dose;
[0131] FIG. 16 is a perspective rear side view of the inhaler of FIG. 1 with the cap in the open position and the dispensing mechanism unloaded having dispensed a dose;
[0132] FIG. 17 is a perspective rear side view of the inhaler of FIG. 1 with the cap in the open position and the dispensing mechanism partially reset, with the reset load being held by the prevention mechanism,
[0133] FIG. 18 schematically shows the various stages of operation and potential misuse of a typical breath actuated inhaler,
[0134] FIG. 19 schematically shows the various stages of operation of a breath actuated inhaler having a prevention mechanism in accordance with the present invention, and
[0135] FIG. 20 is a perspective view of a prevention mechanism in accordance with the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0136] Referring now to FIG. 1, a breath actuated inhaler (BAI) 100, in accordance with embodiments of the present invention, is shown. The inhaler 100 comprises a housing or back cover 10, a mouthpiece cover or cap 2 and a front fascia 30 having an aperture through which is visible a counting mechanism 200. A magnifying protective cover (not shown) fills the aperture and shields the counter mechanism from ingress of dirt and other undesirable particulates, whilst enhancing the visibility and brightness of the counter digits. The fascia 30 preferably has a line of weakness (not shown) such that, if it is attempted to forcibly remove the fascia 30 and access the internal components, the line of weakness shows as a deformation or change in the plastic (e.g. colour change or other visible weakness) in the outer surface of the fascia 30, indicating that the inhaler 100 has been tampered with and should not be used.
[0137] FIG. 2 shows some of the internal components of the inhaler 100, as the back cover 10 and front fascia 30 has been removed. FIG. 6 also illustrates the components of s FIG. 2 but in perspective view. In these figures, the inhaler 100 is in the neutral or rest position with the cap 2 closed and covering the mouthpiece, which is the preferred state of the inhaler 100 when it is not in use. A canister of medicament 20 (which typically holds a suspension or solution of one or more active pharmaceutical ingredients in a propellant under pressure) is housed in the inhaler 100. Such canisters 20 are well known in the art.
[0138] A yoke 4 is shown in its uppermost position and a coiled spring 6 is shown in a loaded state, thus storing an actuation or dispensing force. Most of the mechanical components of the inhaler, except the yoke 4, are unloaded and there is no compression of the canister 20. The yoke 4 is supported by the cap 2, specifically by a cam surface 3 of a cam 110 of the cap 2. Thus in the neutral position, the loaded spring force (typically of about 50 N) is held by the yoke 4, which is typically formed of a material that is resistant to flexing and buckling (such as polyoxymethylene, e.g. Ultraform N 2720 (M60)). A lever 50 and a lever lock 53, both parts of a releasable locking arrangement, are each in their locked positions, although may not be under tension. A further component of the releasable locking arrangement is a drop link 55, which is shown in its latched position whereby it rests upon a pivot shaft 58 of a breath-actuated element, vane 57, thus able to hold the lever lock 53 in its locked position. A return spring 210 abuts the inner surface of the back cover 10 when the inhaler 100 is assembled, to bias the releasable locking arrangement into the locked position so that it will lock when under tension or load.
[0139] A manual firing button 48 is provided and enables the user to deliver a dose of medicament as an emergency function if, for any reason, the usual dispensing mechanism fails, or if the user otherwise cannot breath actuate the dispensing mechanism to deliver a dose of medicament, for example, during a chronic asthma attack. Alternatively the button 48 can be used to test and/or prime the inhaler 100 or simply as an alternative firing mechanism if desired.
[0140] Most of the mechanical components of the inhaler 100 are retained in a chassis 40, which is not shown in FIG. 2 but is shown in later figures (such as FIG. 9). Most of the components of the dispensing mechanism are pivoted on, engaged with, or supported by the chassis 40.
[0141] FIG. 3 illustrates the inhaler 100 when it is ready to be used/fired. FIG. 7 also illustrates the components of FIG. 3 but in perspective view. The cap 2 is opened to uncover a mouthpiece 60. As the cap 2 pivots on opening, the yoke 4 moves downwardly under the force of the spring 6 to engage the base of the canister 20. However compression of the canister 20 to deliver a dose of medicament is substantially prevented by the releasable locking arrangement which is becomes engaged as the yoke 4 moves and holds the load of the spring 6, the lever lock 53 holding the lever 50. In this primed or dispensing state, the inhaler 100 is loaded, ready to fire and deliver a dose of medicament.
[0142] Inhalation by the user at the mouthpiece 60 causes air to flow through the air flow path defined inside inhaler 100. Due to the pressure drop created by the air flow (or use of the firing button 48 if manual actuation occurs), the vane 57 pivots and releases the drop link 55. The vane 57 is configured to be of a suitable size and shape such that it is able to move under a relatively low pressure drop, and the inhalation channel is configured such that the gap between the edge of the vane 57 and the channel remains substantially the same as the vane 57 rotates under inhalation. Movement of the drop link 55 allows the lever lock 53 to release the lever 50, which is biased into its released position by the load of the spring 6 acting on the yoke 4 which pushes on the yoke protrusions 82 of the lever 50. The lever 50 in its unlocked state allows the coiled spring 6 to unload and to compress the canister 20 to deliver a dose of medicament. The dispensing mechanism also triggers an adjustment of the counter 201 of the counting mechanism 200.
[0143] FIG. 4 illustrates the components of the inhaler 100 after a dose of medicament has been dispensed. FIG. 8 also illustrates the components of FIG. 4 but in perspective view. In order to be able to dispense a further dose of medicament, the inhaler 100 must be fully reset from the FIG. 4 configuration to the dispensing state shown in FIG. 3. Fully resetting the inhaler 100 allows the metering valve 21 (see FIG. 5) of the canister 20 to refill with medicament. It also causes the lever 50 to return to a position where it can be locked by the lever lock 53, which is pushed back into its locking position by the spring 210. The drop link 55 is also pushed back into place by the spring, thus readying the releasable locking arrangement to again lock the dispensing mechanism and prevent actuation until the inhaler is fired.
[0144] Resetting of the inhaler 100 is achieved by closing the cap 2 so that the cam surface 3 pushes the yoke 4 upwards, which in turn pivots the lever 50, etc., and returns the inhaler 100 to the state shown in FIG. 3. Further details of the resetting mechanism are discussed below, in particular in relation to the prevention mechanism to prevent the inhaler 100 being only partially reset.
[0145] FIG. 5 is an exploded view of a typical inhaler 100, such as one in accordance with embodiments of the present invention. The component parts are shown in the unassembled state. The counting mechanism 200 is shown separately but is insertable into the chassis 40 such that at least the display of the counter 201 of the counting mechanism 200 is visible through an aperture in the fascia 30.
[0146] FIGS. 9 and 10 show a chassis 40 in accordance with embodiments of the present invention. The chassis 40 comprises an injection moulded polyoxymethylene copolymer, such as Hostaform MT12U03, although other suitable materials and/or manufacturing techniques can be used to form a chassis 40 suitable for use in embodiments of the present invention. The chassis 40 is a primary structural component of the exemplified inhalers 100 and defines many of the pivot points of the inhaler mechanisms and also defines the position of many the other components of the inhaler 100.
[0147] In the embodiment shown in FIGS. 9 and 10, the chassis 40 also defines one of the components of a prevention mechanism 70. As most clearly shown in FIG. 10, the chassis comprises an integrally formed second engaging member 74. The second engaging member 74 projects generally upwards when the chassis 40 is located in the inhaler 100 and the inhaler 100 is held in an upright position. The second engaging member 74 is sufficiently flexible such that it can be deflected out of the plane of the chassis side (i.e. in direction A as shown in FIG. 20 and also in a direction substantially directly opposite to A). At the upper end of the second engaging member 74 there is provided an engaging portion 75, which is a hooked-shaped portion having a protruding tooth or hammer head. The tooth is configured for engagement in a mating configuration with an engaging portion 73 of a first engaging member 72, which is shown in FIGS. 11 to 13. The tooth 75 is angled to aid in locating and retaining the tooth 75 in the engaging portion 73 of the first engaging member 72. The second engaging member 74 is also sufficiently flexible such that it can be deflected generally towards the chassis (i.e. in direction B as shown in FIG. 20) such that the tooth 75 is brought into abutment with the chassis 40. As well as being sufficiently flexible to be deflectable in this ways described above, the second engaging member 74 is also sufficiently resilient such that it will reliably return to its initial position once the deflecting force(s) is removed. Although only one second engaging member 74 is visible on the chassis 40 of FIGS. 9 and 10, there is provided a further second engaging member 74 of the same configuration but on the opposite side of the chassis 40, which is not visible in these figures.
[0148] FIG. 11 shows a lever 50 for the inhalers 100 shown in the figures. The lever 50 is a generally symmetrical component that is held in a pivotable configuration by the chassis 40. Chassis protrusions 80 (only one of which is shown in FIG. 11) are provided for engagement with the chassis 40 when the inhaler 100 is assembled (as shown in FIG. 13). In use, e.g., when dispensing a dose of medicament, the lever 50 pivots about these chassis protrusions 80. The lever 50 also comprises two yoke protrusions 82 (only one of which is shown in FIG. 11) which engage with the yoke 4 when the inhaler 100 is assembled such that movement of the yoke 4 (e.g. under the force of the spring 6 or when resetting the inhaler 100 using the cap 2) is translated to the lever 50 and pivots the lever 50 about the chassis protrusions 80.
[0149] Lever 50 further comprises a pair of counter protrusions 92 for engaging and actuating the counting mechanism 200. The counter protrusions 92 are curved such that, if the lever 50 rotates too far, the counter protrusions can disengage from the counting mechanism 200 to avoid overcounting. Lever 50 also comprises an abutting protrusion 52 that is configured to rest against a portion of a lever lock 53 when the inhaler 100 is in its armed state (as shown in FIGS. 3, 7 and 12).
[0150] Lever 50 further comprises a pair of first engaging members 72 that protrude from the lever 50, each having a respective engaging portion 73 (only one shown in FIG. 11) generally at an end thereof. The engaging portions 73 are shaped to receive a tooth of the respective engaging portions 75 of the second engaging members 74 of the chassis 40. When the engaging portions 75 of the second engaging members are received in the engaging portions 73 of the first engaging members 72 any tensile force pulls the engaging members 72, 74 further into a mating configuration and prevents the engaging members 72, 74 being pulled apart. This arrangement locks the lever 50 against rotation about the chassis protrusions 80 even if the yoke 4 acts on the lever 50 via the yoke protrusions 82 and attempts to move it.
[0151] Operation of the inhaler 100 will now be described with a focus on the rle of the prevention mechanism 70. FIGS. 14 to 17 show the inhaler 100 at different stages of operation. In FIG. 14, the inhaler 100 is in the neutral or rest state, which is the preferred state for storing the inhaler 100 between uses. The prevention mechanism 70 comprises a pair of first engaging members 72 integrally formed with the lever 50 (of which only one is shown in FIG. 14) and a pair of first engaging members 74 integrally formed with the chassis 40 (of which only one is shown in FIG. 14 and for clarity, the rest of the chassis 40 has been removed, including the portions against which the engaging portions 75 of the second engaging members 74 abut when the engaging portions are engaged in the mating configuration and are under load). In the rest state, the engaging portion 75 of the second engaging member 74 sits above and separate from the engaging portion 73 of the first engaging member 72. Furthermore the engaging portion 75 is not in contact with the substantially rigid component of the inhaler 100, which in the shown inhaler is another part of the chassis 40.
[0152] When a patient wishes to inhale a dose of medicament, the first operation step is to open the mouthpiece cap 2 to expose the mouthpiece 60, as shown in FIG. 15. The cap 2 is pivotally mounted on the chassis 40 and has a cam 110 at the pivot point. Pivotal movement of the cap 2 from the second or closed position to the first or open position allows the yoke 4 to move downwards, under the force applied by the coiled spring 6. As the yoke 4 moves downwards the load of the compressed spring 6 transfers from the yoke 4 (which rests on the cam surface 3, when the cap 2 is fully closed), to being held by the releasable locking arrangement, as the cap 2 is opened. Specifically as the cap 2 opens, the lever 50 rotates and the lever abutting protrusion 52 contacts with, and is locked by, the lever lock 53 which is held by the drop link 55 that rests on the pivot shaft 58 of the vane 57 to hold the load of the spring 6. This can be seen in FIG. 15, as when the cap 2 is fully opened, there is space between the foot of the yoke 4 and the cam surface 3 of the cap 2. Although, as the load is transferred to the releasable locking arrangement the lever 50 pivots slightly about the chassis protrusions 80 as the yoke 4 moves downwards, any such movement of the lever 50 will be minimal and will not engage or otherwise affect the prevention mechanism 70, as can be seen in the close-up view of FIG. 15.
[0153] After opening the cap 2 of the inhaler 100, thus arming it such that a dose is ready to be dispensed (known as the prefire point or condition), the patient inhales through the mouthpiece 60. The pressure drop in the airflow passage through the inhaler 100 releases the releasable locking mechanism. Specifically the pressure drop causes the vane 57 to pivot about its pivot shaft 58 generally towards the mouthpiece 60, which allows the drop link 55 to disengage from the top surface of the vane, thus allowing the lever lock 53 to be pushed away by the lever abutting protrusion 52, which frees the lever 50 to pivot on the chassis protrusions 80 under the force of the compressed spring 6 (which acts on the yoke 4 which in turn acts on the lever 50 via the yoke protrusions 82). The downward movement of the yoke 4 under the full force of the expanding spring 6 compresses the valve stem 24 of the canister 20 against a nozzle block 62 of the inhaler 100 (in this embodiment, the nozzle block 62 is an integral part of the mouthpiece 60 but it could be a separately provided component or formed with another component of the inhaler 100). Compression of the valve stem 24 activates the metering valve and dispenses a dose of medicament under pressure into the inhalation airflow and through the mouthpiece 60 to be inhaled by the patient.
[0154] FIG. 16 shows the inhaler 100 after this sequence has occurred, i.e. in the fired or dispensed state, where a dose of medicament has been dispensed and the inhaler 100 has not been reset. The yoke 4 has been deployed under the load of the spring 6 and has moved downward back toward contact with the cam surface 3 of the cap. The lever 50 has pivoted relative to the chassis 40 such that the counter engaging portion 92 has moved downwards and actuated the counting mechanism 200 and the first engaging member 72 has moved upwards. In FIG. 16, the vane 57 has returned to its rest position because the patient has stopped inhaling. However the other components of the releasable locking arrangement cannot return to the rest or neutral position as the abutting protrusion 52 of the lever 50 is still pushing upwards on the lever lock 53 due to the position of the lever 50.
[0155] As mentioned above, as the lever 50 pivoted about the chassis protrusions 80, the end of the lever 50 having the first engaging member 72 (or members as can be seen in the FIG. 16 close up) moved upwards. As can be seen in FIG. 16, in the dispensed state, the engaging portion 73 of the first engaging member 72 has traveled such a distance that it has traveled past the engaging portion 75 of the second engaging member 74 and has finished above and spaced away therefrom. Clearly it is undesirable for the engaging portions 73, 75 of the engaging members 72, 74 to engage in a mating configuration during dispensing of a dose of medicament. Therefore the engaging portions 73, 75 are configured such that if the first engaging member portion 73 moves upwards from a position below the second engaging member portion 75, then as the engaging portions 73, 75 come into contact, one or both of the engaging portions 73, 75 is deflected by the other of the engaging portions 73, 75 such that they pass each other without engaging in the mating configuration. In the present embodiment, the engaging portions 75 of the second engaging members 74 (i.e. those formed on the chassis 40) are deflected inwardly (i.e. are squeezed slightly towards each other) by the more rigid engaging portions 73 of the first engaging members 72 (i.e. those formed on the lever 50).
[0156] After inhaling a dose of medicament, the patient is encouraged to reset the inhaler 100 by the configuration of the device, since it is not possible to dispense further doses until it has been fully reset. This not only ensures that the inhaler 100 is returned to its preferred rest state (in which it is configured to hold the load of the spring 6 through the yoke 4, which is a relatively strong component of the inhaler 100 and is designed to hold such a load reliably and without damage thereto) but also that the mouthpiece 60 is covered straight after use, thus preventing or minimising ingress of dirt and other undesired particles or contaminants into the inhaler 100. To reset the inhaler 100, the patient only needs to pivot the cap 2 back from the first (open) position to the second (closed) position. The cam 110 of the cap 2 is engaged with the yoke 4 and as the cap 2 rotates, the cam surface 3, which is helically shaped, helps push the yoke 4 upwards, thus reloading the spring 6 and moving the other components, particularly those of the releasable locking arrangement, back into the rest state.
[0157] However, it is possible that the patient might not fully reset the inhaler 100, i.e. may not move the cap 2 all the way from the first, open position to the second, closed position. This may be because, for example, the patient is distracted during the resetting motion and releases the cap 2, or the patient may lose their grip on the cap 2, or it may be that the patient plays with the cap 2 and repeatedly move it partially in and out of the open position, without ever fully closing the cap 2. This is undesirable as it might lead to the inhaler 100 not fully functioning when the next dose is dispensed, for example because the metering valve does not fully refill, or insufficient load is stored in the spring 6 to fully activate the valve. Still further, the inhaler 100 may not be reset to the point at which the counting mechanism 200 is reset, which means that any dose dispensed subsequently, even if not a full dose, will not be counted and the counter 201 may therefore inaccurately reflect the number of doses of the inhaler 100.
[0158] The prevention mechanism 70 is configured to solve all the above problems. If the cap 2 is not fully moved from the open position to the closed position, i.e. if the patient stops rotating the cap 2 when it is in some intermediate position and the spring force would therefore bias the yoke 4 to rotate the cap 2 back into the open position, the prevention mechanism 70 engages to hold the load of the spring 6 until the cap 2 completes its movement to the fully closed position, in which the inhaler 100 is fully reset. Thus the yoke 4 is not biased by the spring 6 as the prevention mechanism prevents such biasing. As can be seen in FIG. 17, the engaging portions 73, 75 are configured such that if the second engaging member portion 75 moves upwards from a position below the first engaging member portion 73, then as the engaging portions 73, 75 come into contact they are capable of engaging in the mating configuration, should rotation of the cap 2 to the closing position cease. In the present embodiment, in order to optimise the mating engagement, engaging portions 73, 75 are configured such that as they initially come into contact, one or both of the engaging portions 73, 75 is deflected by the other of the engaging portions 73, 75 such that the deflected engaging portion(s) snap into the mating configuration. In the present embodiment, the engaging portions 75 of the second engaging members 74 (i.e. those formed on the chassis 40) are again deflected, but this time outwardly (i.e. are deflected slightly away from each other) by the more rigid engaging portions 73 of the first engaging members 72 (i.e. those formed on the lever 50). Once the engaging portions 75 have passed beyond a certain point, they deflect back inwards (as the material from which they are formed is relatively resilient) and snap or slot into the engaging portions 73 of the first engaging members 72, which are sized and shaped to snugly receive the teeth of the engaging portions 75 of the second engaging members 74. This configuration can be seen in FIG. 17. Once engaged in the mating configuration, should the cap 2 cease to move and/or move in the opposite direction (i.e. move back towards the first, open position) the load of the spring 6 is held (via the lever 50) by the first engaging members 72 which are pulled in their engaged state against the second engaging members 74. As the second engaging members 74 are flexible, the engaging portions 75 thereof are deflected under this tension generally in direction B (as shown in FIG. 20) and abut a more rigid part of the chassis 40. The tensile load placed on the engaging members 72, 74 in this manner does not disengage the mated engaging portions 73, 75, but rather they are driven together in the mating configuration and by virtue of the abutment with the chassis 40, the force of the spring 6 is readily withstood by a mixture of tension between the first and second engaging members 72, 74 and compression of the engaging portions 75 of the second engaging members 74 against the more rigid portion of the chassis 40. Thus the first and second engaging members 72, 74 are strong and reliable and will not suffer significant material creep nor permanent damage or deflection.
[0159] When the cap 2 resumes its motion towards the second, closed position however, the force through the second engaging members 74 is relieved and they return to their rest position (i.e. no longer abut the chassis 40) and the engaging members 72, 74 are effectively pushed together or compressed by the resumed movement of the lever 50. The engaging members 72, 74 are configured such that a compressive force or motion readily disengages the mated engaging portions 73, 75 (in this embodiment, by the more rigid engaging portions 73 of the lever 50 again causing deflection of the chassis engaging portions 75 outwardly). The cap 2 can then progress to the fully closed state and the inhaler 100 will be fully reset thus providing an inhaler 100 that will reliably dispense and count any further doses of medicament.
[0160] Although the above disclosed embodiments of the present invention have first and second engaging members 72, 74 integrally formed with the lever 50 and the chassis 40 respectively, this is an exemplary arrangement and is not limiting to the scope of the present invention. Alternative arrangements are envisaged, for example one or both of the engaging members 72, 74 may be separately formed components and/or one or both of the engaging members 72, 74 may be integrally formed with one or more other components of the inhaler 100. The more rigid component of the inhaler 100 against which the first and/or second engaging members 72, 74 abuts may be a component of the chassis 40 as discussed above, but may alternatively or additionally be any other suitable component.
[0161] FIGS. 18 and 19 schematically illustrate the above operation of an inhaler 100 in accordance with the present invention, with reference to the various trigger points in the operating cycle. Under normal use starting from the inhaler 100 rest or neutral position (cap closed), the cap 2 must be opened which, as shown under normal operation (closest to the left axis in both figures) moves the inhaler 100 in the dispensing direction through the following steps, in order: (i) the yoke 4 contacts the canister 20 (assuming it does not rest in a contacted state); (ii) the mechanism reaches the prefire point, where the inhaler 100 is primed and ready to fire (but is prevented from doing so by the releasable locking arrangement. Thereafter, when the inhaler 100 is actuated/fired, the inhaler 100 operates in a dispensing direction through the second part of the cycle in which: (iii) the mechanism compresses the canister past the valve firing point (fire point), at which a dose of medicament is dispensed; (iv) the mechanism moves the counter through the counting point at which the counting mechanism 200 is actuated and a dose is counted by the counter 201; and finally (v) the mechanism reaches the end of stroke (final rest/dispensed) position. Steps (iii) and (iv) typically occur in the above order although step (iv) can occur before step (iii). In inhalers in which a dose is automatically counted as the inhaler fires, it is essential that every dose is counted and that the counter never counts when a dose is not dispensed. To achieve this, ideally the fire point and counting point should be as close together as possible to minimise the potential for one to be reached without then reaching the other (i.e. steps (iii) and (iv) occur as close together as possible, no matter in which order they occur). Furthermore, to ensure a full dose of medicament is always dispensed, such an inhaler must be fully reset, at least past the prefire point and preferably past the BAI reset point before a subsequent dose is dispensed. Resetting occurs when the inhaler 100 moves in the resetting direction through the following steps, in order: (i) the mechanism passes the valve 21 reset point (i.e. the refill point, which is the position that, when the inhaler 100 is reset by rotation of the cap 2 in the resetting direction, the mechanism must reach for the valve 21 of the canister 20 to begin to refill; (ii) the mechanism passes the counter 201 reset point (i.e. the position that, when the inhaler 100 is reset by rotation of the cap 2 in the resetting direction, the mechanism must reach to be ready to subsequently count another dispensed dose); (iii) the mechanism passes the inhaler 100 reset point (i.e. the BAI reset which is the position that, when the inhaler 100 is being reset by rotation of the cap 2 in the resetting direction, the mechanism must reach to be fully reset and ready to subsequently actuate/refire).
[0162] As shown in FIG. 18, if the device is not fully reset (i.e. does not reach the BAI reset due to, e.g., incomplete cap closure (such as interrupted cap closure or cap tampering)), it is still possible for the inhaler to dispense at least a partial further dose that may be counted as a whole dose. In the interrupted cap closure example, the cap 2 ceases movement when the inhaler 100 has passed the refill point, so the valve 21 begins to fill with medicament, but before the counter reset point is reached. Therefore if the inhaler 100 refires, whatever dose has filled the valve 21 is released (at the fire point), but is not counted (although the inhaler 100 passes back through the count point, the counter has not been reset so no count occurs). Thus the inhaler 100 undercounts. In the cap tampering example, the inhaler 100 passes beyond the counter reset point, but does not reach the BAI reset. In the dispensing direction, cap 2 movement is reversed after the fire point but before the counting point (even though they are close together), so a dose is dispensed but not counted as the count point is not reached. Thus the inhaler 100 undercounts. The inhalers of FIG. 18 are not in accordance with the present invention as there is no mechanism to prevent actuation (or at least prevention of the inhaler 100 reaching the fire/count point) when the inhaler has not been fully reset.
[0163] FIG. 19, however, shows operation of an inhaler 100 in accordance with the present invention, having a prevention mechanism as previously described. As is shown in the figure, normal operation does not differ from the FIG. 18 examples. However, when cap 2 closure is interrupted or the cap 2 is tampered with before the inhaler 100 is reset to at least the BAI reset point, the prevention mechanism engages and prevents movement in the dispensing mechanism beyond a blocked point (shown as the horizontal red line). The blocked point is before the inhaler 100 can reach the fire or counting point. Thus the dispensing mechanism does not dispense nor the counter count as the inhaler 100 cannot reach the fire point or counting point, until the cap 2 is closed and the inhaler 100 reset at least to the BAI reset point.
