Dose counter

Abstract

Generally, the present invention proposes a dose counter for recording a count of doses dispensed from an inhaler. The dose counter comprises a counter ring comprising a circumferential drive feature. The dose counter further comprises a worm comprising a shaft and a gear extending along a helical path about an axis of the shaft to drive the counter ring. The gear comprises recesses evenly distributed along the helical path. The dose counter further comprises a cylindrical body comprising an engagement feature for driving the gear, the engagement feature extending from the cylindrical body along a helical or spiral path to engage the gear such that relative rotational motion between the cylindrical body and the worm causes the worm to rotate about its shaft.

Description

TECHNICAL FIELD

[0001] The present invention relates to a dose counter. In particular, but not exclusively, the present invention relates to a dose counter for recording the count of doses dispensed from an inhaler, and to an inhaler comprising the dose counter. BACKGROUND

[0002] Patients using inhalers such as soft mist inhalers (SMI), pressurised metered dose inhalers (pMDI) and dry powder inhalers (DPI) need to monitor their usage of the inhaler. Furthermore, pharmaceutical regulatory bodies have started to require some form of dose indication method to be included in inhalers. Dose counters which provide an accurate count of the number of doses remaining and dose indicators which indicate the proportion of doses remaining are both known.

[0003] There have been many proposals for dose counters for use with inhalers (whether the inhaler is for example a dry powder inhaler, a portable nebuliser, a pressurised metered dose inhaler or some other type of inhaler). However, despite the progress made, there is still a pressing need for a dose counter which is both economical and reliable.

[0004] In most dose counters and indicators, a display is indexed each time the inhaler is used. Many dose counters and / or dose indicators are complex and require several small mechanical components. This can increase cost, cause difficulties in assembly and often requires tight dimensional manufacturing tolerances.

[0005] Accordingly, there is still a need for an improved dose counter which can overcome the above-mentioned disadvantages. It is an object of the present invention to address at least one of the problems mentioned above or other issues associated with the prior art. SUMMARY

[0006] A first aspect of the present invention provides a dose counter for recording the count of doses dispensed from an inhaler. The dose counter comprises a counter ring comprising one or more circumferential drive features. The dose counter further comprises a worm comprising a shaft and a gear extending along a helical path about an axis of the shaft to drive the counter ring. The gear comprises one or more recesses distributed along the helical path of the gear. The dose counter further comprises a cylindrical body comprising an engagement feature for driving the gear, the engagement feature extending from the cylindrical body along a helical or spiral path to engage the gear such that relative rotational motion between the cylindrical body and the worm rotates the worm about the shaft.

[0007] In this way, the dose counter can advantageously utilize the rotational movement of the columnar body to operate and drive the counter ring. Importantly, this can allow the remaining number of doses of the inhaler to be measured with fewer components. This in turn can advantageously simplify the manufacture of the dose counter. Furthermore, such a dose counter can suitably be used in any situation where the priming operation of the inhaler causes some rotational movement, and can thus be applied to many types of inhaler.

[0008] In some embodiments, the dose counter can comprise a transmission mechanism for converting the linear or reciprocating movement of the inhaler into rotational movement of the columnar body. This can advantageously enable the columnar body to rotate in the case where the priming operation of the inhaler is linear or reciprocating.

[0009] The term "dose counter" as defined herein is considered to encompass both mechanisms that use a numerical count to indicate the number of doses remaining, and dose indicating mechanisms that do not count the number of doses actuated. Such dose indicating mechanisms can for example use colour coding or other means to indicate the proportion of doses remaining or to indicate that the device is nearing the end of its useful life.

[0010] Suitably, the gear wheel can comprise two, three, four, five, six, seven, eight, nine or even ten recesses distributed along the helical path of the gear wheel (i.e. the helical path of the gear wheel about the axis of the worm shaft). In some embodiments, the recesses can be evenly distributed along the helical path of the gear wheel.

[0011] Suitably, the gear wheel can comprise a plurality of teeth distributed along the helical path of the gear wheel. Thus, the one or more recesses can be defined by one or more gaps between the plurality of teeth.

[0012] In some embodiments, the drive of the worm on the counter ring can be constrained in one direction. For example, the drive of the worm on the counter ring can be constrained in one direction by a ratchet. Suitably, the ratchet can comprise a pawl configured to engage the counter ring, the worm and / or the columnar body to prevent counter ring reverse rotation.

[0013] In some embodiments, the engagement feature can comprise a ribbed worm tooth.

[0014] In some embodiments, a cross-section of the engagement feature generally orthogonal to the helical or spiral path can have an engagement shape. The engagement shape can suitably be configured to fit into each recess of the gear wheel of the worm. For example, as the worm rotates about its shaft, the orientation of the engagement shape can change along the path of the engagement feature, such that the engagement shape remains fitted into at least one of the one or more recesses of the gear wheel.

[0015] In some embodiments, the orientation of the engagement shape can be changed by a single rotation along the path of the engagement feature.

[0016] Suitably, the engagement shape can be configured to fit snugly into each recess.

[0017] In some embodiments, the engagement shape can be substantially square. For example, the engagement feature can comprise a ribbed worm tooth having a substantially square cross-section. In such embodiments, the recess can define a substantially right-angled corner (i.e. have a cross-section in the form of a right-angled corner along the helical path of the gear). For example, the cross-section of the recess can be substantially L-shaped.

[0018] In some embodiments, the engagement shape can be substantially triangular. For example, the engagement feature can comprise a ribbed worm tooth having a substantially triangular cross-section. In such embodiments, the recess can be substantially acute-angled (i.e. have a cross-section in the form of a vertex of a triangle along the helical path of the gear). For example, the cross-section of the recess can be substantially < -shaped.

[0019] In some embodiments, the engagement shape can have a substantially involute profile.

[0020] In some embodiments, the engagement feature can be configured to engage the gear at at least two different locations along the helical or spiral path of the engagement feature simultaneously.

[0021] In some embodiments, the cylindrical body can comprise a plurality of engagement features. For example, the cylindrical body can comprise two, three, four, five, six, seven, eight, nine or even ten engagement features. In such embodiments, the plurality of engagement features can extend along helical or spiral paths that are parallel in rotation.

[0022] In some embodiments, the cylindrical body can comprise two engagement features configured to engage the gear simultaneously. For example, the two engagement features can be configured to engage the gear at at least one location on the helical or spiral path of each of the two engagement features.

[0023] In some embodiments, the helical path of the gear can extend less than one full revolution around the axis of the axis of the worm. In some embodiments, the helical path of the gear can extend one full revolution around the axis of the axis of the worm.

[0024] In some embodiments, the helical path of the gear can extend one full revolution or more around the axis of the axis of the worm. This can advantageously ensure engagement at all times throughout the motion.

[0025] In some embodiments, the dose counter can comprise a housing. Suitably, the worm can be mounted in the housing.

[0026] In some embodiments, the dose counter can comprise a locking arm coupled to the housing. Suitably, the locking arm can engage with an engagement feature of the columnar body after the final dose has been recorded. This can advantageously prevent further movement (e.g. rotation) of the columnar body, for example after a predetermined count of doses has been dispensed from the inhaler.

[0027] In some embodiments, a feature on the counter ring can be provided to release a biasing component or element configured to engage with the columnar body to prevent further movement (e.g. rotation) of the columnar body relative to the counter ring after the final dose has been recorded. This can advantageously prevent further movement of the columnar body, for example after a predetermined count of doses has been dispensed from the inhaler. Suitably, the feature on the counter ring can comprise a missing tooth, a filled tooth or an interruption or protrusion from the counter ring. The biasing component or element can comprise a spring or a stamped metal component. The biasing component or element can be configured to engage with the engagement feature or an engagement feature or to engage with other features of the columnar body.

[0028] In some embodiments, the dose counter can comprise a spring metal component. In such embodiments, a portion of the periphery of the counter ring can comprise a gap for receiving the spring metal component. Suitably, the spring metal component can be anchored to a portion of the inhaler comprising the dose counter, for example the housing or mouthpiece of the inhaler. In this way, a leading edge of the spring metal component can be provided to move into the gap and into the path of the engagement feature. This can prevent further movement (e.g. rotation) of the columnar body, for example relative to the housing or mouthpiece, after the final dose has been recorded. This can advantageously prevent further movement of the columnar body, for example after a predetermined count of doses has been dispensed from the inhaler.

[0029] In some embodiments, the dose counter can comprise a spring and a rigid locking component. Suitably, the spring and the rigid locking component can be located in a guide feature. The guide feature can be fixed to a portion of the inhaler comprising the dose counter, for example the housing or mouthpiece of the inhaler. The spring can be configured to be released by the counter ring to move into the path of the engagement feature. This can prevent further movement (e.g. rotation) of the columnar body, for example relative to the housing or mouthpiece, after the final dose has been recorded. This can advantageously prevent further movement of the columnar body, for example after a predetermined count of doses has been dispensed from the inhaler. The rigid locking component can be provided to prevent the spring from disengaging after engagement with the columnar body.

[0030] In some embodiments, the dose counter can comprise a locking clip. The locking clip can be suitably attached to the counter ring. The locking clip can be arranged to be movable by the worm into a position in which it engages the engagement feature to prevent further movement of the cylindrical body. For example, the locking clip can be arranged such that engagement of the locking clip with the worm moves the locking clip from a first (unlocked) position in which the locking clip is substantially flush with the counter ring (i.e. lies substantially in the same plane as the counter ring) such that the locking clip does not block the path of the engagement feature, to a second (locked) position in which the locking clip is inclined relative to the counter ring such that the locking clip blocks the path of the engagement feature.

[0031] In this way, once the locking clip is engaged with the worm, the worm can be held in place relative to the counter ring, thereby locking the cylindrical body to the counter ring and preventing further movement (e.g. rotation) of the cylindrical body relative to the counter ring. Suitably, the worm can be mounted on a fixed portion of the housing or mouthpiece. Thus, locking the cylindrical body to the counter ring can prevent further movement (e.g. rotation) of the cylindrical body relative to the housing or mouthpiece after the final dose has been recorded.

[0032] In some embodiments, the cylindrical body can be part of a second housing of the dose counter.

[0033] In some embodiments, the cylindrical body can be hollow.

[0034] In some embodiments, the engagement feature can suitably extend from an outer surface of the cylindrical body.

[0035] In some embodiments, the counter ring and the cylindrical body can share a common axis. For example, the counter ring and the cylindrical body can rotate about a common axis.

[0036] In some embodiments, the drive feature circumferentially of the counter ring can comprise regularly spaced teeth or ribs.

[0037] In some embodiments, the circumferential drive feature can extend around a portion of the perimeter of the counter ring. Suitably, the circumferential drive feature can be interrupted by an interruption. For example, where the circumferential drive feature comprises regularly spaced teeth or ribs, the circumferential drive feature can be interrupted by an interruption located in the regular spacing of the teeth or ribs. Suitably, the interruption can be in the form of a wider gap or a gap filled.

[0038] In some embodiments, the dose counter can comprise between 1 and 12 engagement features. For example, the dose counter can comprise one, two, three, four, five, six, seven, eight, nine, ten, eleven or even twelve engagement features.

[0039] In some embodiments, the ratio of the angular advancement of the counter ring relative to the angular movement of the columnar body can be in the range of 2:5 to 1 :400, in the range of 2:5 to 1 :300, in the range of 2:5 to 1 :200, in the range of 2:5 to 1 :100, in the range of 2:5 to 1 :80, in the range of 2:5 to 1 :60, in the range of 2:5 to 1 :40, or even in the range of 2:5 to 1 :20.

[0040] A second aspect of the present application provides an inhaler (i.e. inhalation device) comprising a dose counter according to the first aspect of the present application.

[0041] In some embodiments, the inhaler can be suitably configured for nebulising a liquid medicament. For example, the inhaler can be a soft mist inhaler (SMI).

[0042] In some embodiments, the inhaler can be suitably configured for delivering a dry powder medicament. For example, the inhaler can be a dry powder inhaler (DPI).

[0043] Throughout the description and claims of this specification, the words "comprise" and "contain" and variations of the words, for example "comprising" and "comprises", means "including but not limited to", and the

[0044] Preferred features of each aspect of the application can be applied to any other aspect of the application. It is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and / or in the following description and drawings, in particular any feature mentioned in conjunction with one aspect, embodiment example or alternative, can be applied, to any other aspect, embodiment, example or alternative of the application, alone or in combination with other features and / or aspects. That is, features described in the context of one aspect, embodiment or alternative are not only applicable to that aspect, embodiment or alternative, but also to other aspects, embodiments or alternatives, alone or in combination with other features and / or aspects. BRIEF DESCRIPTION OF DRAWINGS

[0045] One or more embodiments of the application will now be described, by way of example only, with reference to the accompanying drawings in which:

[0046] FIG. 1AA perspective view of a dose counter according to a first embodiment of the application is shown, viewed from above and from one side, the dose counter having a hollow cylindrical body concentrically located within a cylindrical counter ring, the cylindrical body and counter ring being concentrically arranged in a housing chassis and rotatable relative to one another, a first end of the cylindrical counter ring comprising a circumferential drive feature having a plurality of equally spaced teeth-like protrusions extending from the first end of the counter ring, a worm gear being engaged to the cylindrical body and counter ring, the worm gear having a cylindrical shaft. End portions of the cylindrical shaft are rotatably mounted in a generally cylindrical slot in the housing.

[0047] FIG. 1B A side view cross-sectional view of the dose counter in FIG. 1A is shown;

[0048] FIG. 1C A top view of the dose counter in FIG. 1A is shown;

[0049] FIG. 1D A side view of the dose counter in FIG. 1A when in a locked position is shown;

[0050] FIG. 2A A perspective view of the cylindrical body in FIGS. 1A-1D is shown;

[0051] FIG. 2B A side view of the cylindrical body in FIGS. 1A-1D is shown;

[0052] FIG. 3 A perspective view of the worm gear in FIGS. 1A-1D is shown;

[0053] FIG. 4A A side view of the dose counter in FIGS. 1A-1D before rotation of the cylindrical body relative to the counter ring is shown;

[0054] FIG. 4B A side view of the dose counter in FIG. 4A after a 90 degree counter clockwise rotation of the cylindrical body is shown;

[0055] FIG. 4C A side view of the dose counter in FIG. 4B after a further 90 degree clockwise rotation of the cylindrical body is shown;

[0056] FIG. 5A A cross-sectional view of the dose counter in FIGS. 1A-1D when located inside a soft mist inhaler (SMI) device is shown;

[0057] FIG. 5B A cross-sectional view of the dose counter in FIG. 5Apartial cross-sectional view of a soft mist inhaler (SMI) device in which the dose counter is located, showing the spring biased rigid locking member in the locked position;

[0058] FIG. 6A a perspective view of a dose counter according to a second embodiment of the application, the dose counter in this embodiment being similar to the dose counter in the first embodiment and having a spring metal locking member, shown in the unlocked position;

[0059] FIG. 6B a perspective view of FIG. 6A a dose counter in which the spring biased rigid locking member is shown in the position in which the locking member is released by the dose counter prior to locking occurring;

[0060] FIG. 7 a perspective view of a dose counter according to a third embodiment of the application, the dose counter in this embodiment being similar to the dose counters in the first and second embodiments and having a spring biased rigid locking member;

[0061] FIG. 8A a perspective view of FIG. 6A and FIG. 6B a cross-sectional view of a dose counter in which the spring biased rigid locking member is in the unlocked position when the dose counter is located inside a soft mist inhaler (SMI) device;

[0062] FIG. 8B a perspective view of FIG. 6A and FIG. 6B a cross-sectional view of a dose counter in which the spring biased rigid locking member is in the locked position when the dose counter is located inside a soft mist inhaler (SMI) device;

[0063] FIG. 9A a perspective view of a counter ring and end of life clip according to a fourth embodiment of the application, shown in the unlocked position;

[0064] FIG. 9B a perspective view of FIG. 9A a counter ring and end of life clip in the locked position;

[0065] FIG. 10A perspective view of a dose counter according to a fifth embodiment of the present invention is shown. The dose counter has a disc-shaped counter ring with a central columnar hole and a hollow columnar body. The first end of the hollow columnar body is concentrically located within the central columnar hole of the counter ring. The columnar body is concentrically arranged in a housing frame that forms part of a device such as a dry powder inhaler. The columnar body and the counter ring are each rotatable independently relative to the housing frame. The outer surface of the columnar body includes three engagement features that engage with the teeth of a worm gear. Each engagement feature includes ribbed worm gear teeth with a square engagement shape.

[0066] FIG. 11 It shows FIG. 10 A breakdown diagram of the dose counter in the image;

[0067] FIG. 12A It shows FIG. 10 A side cross-sectional view of the dose counter in the image before the columnar body is rotated relative to the joint feature.

[0068] FIG. 12B It shows FIG. 7 A side cross-sectional view of the dose counter after the columnar body has been rotated 60 degrees counterclockwise;

[0069] FIG. 13A A top view of the columnar body and worm gear according to a sixth embodiment of the present invention is shown; and

[0070] FIG. 13B It shows FIG. 13A A three-dimensional view of the columnar body and the worm gear. Detailed Implementation

[0071] First Implementation Method

[0072] refer to FIGS. 1A-1D According to a first embodiment of the present invention, a dose counter 100 includes a hollow cylindrical body 102 concentrically located within a cylindrical counter ring 104. The cylindrical body 102 is rotatable relative to the counter ring 104. The cylindrical body 102 and the counter ring 104 are concentrically arranged in a housing base 105. The housing base 105 may form part of a device such as a soft mist inhaler (SMI). FIGS. 1A-1D (Not shown in the image), the soft mist inhaler includes a liquid medication supply unit and a mouthpiece for delivering liquid medication to the patient. The cylindrical body 102 and the counter ring 104 can each rotate independently relative to the housing base 105.

[0073] The first end of the columnar counter ring 104 includes a circumferential drive feature 106. In this example, the circumferential drive feature 106 is defined by a plurality of equidistant toothed protrusions 107 extending from the first end of the counter ring 104. The plurality of toothed protrusions 107 define a series of equidistant gaps 108 between them. The plurality of toothed protrusions 107 extend over a large portion of the periphery of the first end of the counter ring 104. The counter ring 104 has an outer surface printed with numerical indicators. The outer surface printed with numerical indicators indicates the amount of liquid drug dose dispensed.

[0074] The dose counter 100 also includes a worm gear 120 that meshes with both the columnar body 102 and the counter ring 104. The worm gear 120 has a columnar shaft 122 and a gear 124. The end of the columnar shaft 122 is rotatably mounted in a generally columnar groove 150 in the housing 105. The gear 124 meshes into a gap 108 and engages with toothed protrusions 107 of a circumferential drive feature 106. The gear 124 extends 360° around the midpoint of the axis of the shaft 122 along a generally helical path and has four teeth 126 evenly distributed along the helical path.

[0075] The outer surface of the columnar body 102 includes a pair of engagement features 130a, 130b that engage with the teeth 126 of the worm 120. In this example, each engagement feature 130a, 130b is a ribbed worm tooth having a square engagement shape (i.e., the cross-section of the ribbed worm tooth is square) and extending 180° along a helical path around opposite sides of the outer surface of the columnar body 102. Each engagement feature 130a, 130b undergoes a 90° twist as it extends around the outer surface of the columnar body 102. The twist of the engagement features 130a, 130b maintains a tight engagement between two adjacent teeth of the worm 126 as the columnar body 102 rotates.

[0076] FIG. 1B and FIG. 1C Side cross-sectional view and top view of dose counter 100 are provided respectively.

[0077] FIG. 1D A side view of dose counter 100 is provided. FIG. 1D As shown, a portion of the periphery of the counter ring 104 is provided with an elongated toothed portion 109, which has no gaps and defines a life-end locking feature. FIG. 1DIn use, the worm 120 is shown abutting the elongated tooth portion 109, which prevents the cylindrical body 102 from further counterclockwise rotation relative to the counter ring 104. In use, this causes the dose counter 100 to be deliberately jammed. This can advantageously prevent the inhaler from releasing more liquid medicament after a predetermined number of doses of liquid medicament has been dispensed when the dose counter 100 is assembled within a soft mist inhaler (SMI) containing liquid medicament.

[0078] FIG. 2A and FIG. 2B respectively provide perspective and side views of the cylindrical body 102, while FIG. 3 provides a perspective view of the worm 120.

[0079] Reference is now made to FIGS. 4A-4C In use, the worm 120 is initially engaged between the first tooth 107a and the second tooth 107b of the circumferential drive feature 106 (as shown in FIG. 4A To use a device (not shown in FIGS. 4A-4C ) comprising the dose counter 100, such as a soft mist inhaler (SMI), a patient rotates a base portion of the device counterclockwise by 180° to provide a dose of medicament from the device through a mouthpiece of the device.

[0080] The base portion of the device is attached to the cylindrical body 102 such that when the base portion is rotated counterclockwise by 180°, the cylindrical body 102 is also rotated clockwise by 180° relative to a housing chassis (not shown). When the cylindrical body 102 is rotated by 180°, the engagement feature 130a of the cylindrical body 102 drives the gear 124 of the worm 120 to rotate the worm 120 by 90°, i.e., 1 / 4 of the pitch between the teeth 107a, 107b (as shown in FIG. 4B ).

[0081] FIG. 4C The dose counter 100 is shown after the base portion, and thus the cylindrical body 102, is further rotated counterclockwise by 90 degrees (for a total of 180 degrees).

[0082] Due to the small increment of rotation, the outer surface of the counter ring 104 is printed with numbers showing increments of 5, 10, or 20 to enable the patient to determine the remaining number of doses. For gear ratios that are comparatively low (such as gear ratios in the range of 2:5 to 1:30), it is feasible to print individual numbers (i.e., 1, 2, 3).

[0083] FIG. 5AA cross-sectional view of a dose counter 100 when assembled within a soft mist inhaler (SMI) device 1 is provided. The device 1 includes a housing 10, the lower half of which houses a cartridge 12 containing a liquid medicament. The upper half of the housing 10 includes a spring holder 16. The spring holder 16 is located directly above the cartridge 12. The dose counter 100 is fixed in place concentrically around the spring holder 16 by the housing 10. A spring cap 14 and a coil spring (not visible in FIG. 5A ) are arranged concentrically within the spring holder 16. The spring cap 14 is a ring-like component located at the upper end of the spring holder 16. A conduit 22 fluidly connects the cartridge 12 to a mouthpiece 30 of the device 1. The conduit 22 passes through the center of the spring cap 14 and coil spring.

[0084] The lowermost end of the housing 10 is attached to a base portion 40 that is rotatable relative to the upper half of the housing 10. A clockwise rotation of the base portion 40 by 180° relative to the upper half of the housing 10 forces the cartridge 12 to move downward, compressing the coil spring 17 and drawing a predetermined volume of liquid medicament from the cartridge 12 through the conduit 22 and out through a micro pump 15 located inside the mouthpiece 30. After the device has been actuated, the liquid medicament is expelled from the micro pump 15 and the device 1, and the coil spring is no longer compressed and the cartridge 12 returns to its original position. The spring cap 14 is rotatably aligned with the spring holder 16 to prevent the transmission of unwanted torque to the device mechanism during actuation of the device 1.

[0085] FIG. 5B is a partial cross-sectional view of the dose counter 100 when assembled within a soft mist inhaler (SMI) device 1, showing the spring cap 14 engaged with the spring holder 16. The spring cap 14 has a plurality of protruding ribs (not visible in FIG. 5B ) that engage and extend in grooves 18 provided in the spring holder 16.

[0086] The base portion 40 is connected to the cylindrical body 102 of the dose counter 100 such that a clockwise rotation of the base portion 40 by 180° causes the cylindrical body 102 to rotate clockwise by 180° relative to the counter ring 104. When the cylindrical body 102 is rotated by 180°, the engagement feature 130a of the cylindrical body 102 drives the gear 124 of the worm 120 to rotate the worm 120 by 90°, i.e. ¼ of the pitch between the teeth 107a.

[0087] A slot 44 in the housing allows the number indicators printed on the outside of the counter ring 104 to be read through the housing. In this example, the number indicators indicate the number of doses of liquid medicament that have been dispensed from the device 1.

[0088] Second embodiment

[0089] Reference FIG. 6AThe dose counter 200 according to the second embodiment of the present application has substantially the same structure as the dose counter 100 of the first embodiment described above, the dose counter 200 having a hollow cylindrical body 202 concentrically located within a cylindrical counter ring 204. The cylindrical body 202 is rotatable relative to the counter ring 204. The cylindrical body 202 and the counter ring 204 are arranged in a housing chassis 205. The housing chassis 205 can form part of a device (not shown in FIG. 6A such as a soft mist inhaler (SMI) including a supply of liquid medicament and a mouthpiece for delivering the liquid medicament to a patient.

[0090] The first end of the cylindrical counter ring 204 includes a circumferential drive feature 206. As with the dose counter 100 described above in relation to the first embodiment of the present application, the circumferential drive feature 206 is defined by a plurality of equally spaced apart toothed protrusions 207 extending from the first end of the counter ring 204. The plurality of toothed protrusions 207 define a series of equally spaced apart gaps 208 therebetween. The plurality of toothed protrusions 207 extend over a majority of the circumference of the first end of the counter ring 204. A portion of the circumference of the counter ring 204 includes a gap 209a for receiving a spring metal component 209b. The spring metal component 209b defines an end-of-life lock feature in place of the elongate tooth portion 109 described above in relation to the first embodiment.

[0091] The spring metal component 209 is anchored to a portion (not shown in FIG. 6A such as the mouthpiece) of the device. The spring metal component 209b is held in a diametrical position by the plurality of toothed protrusions 207 at the start of life (i.e. before use of the device) and whilst the dose counter 200 is counting during the life of the device (i.e. during use of the device).

[0092] Upon the dose counter 200 showing zero, the leading edge of the spring metal component 209b moves in a diametrical direction into the gap 209a, thereby blocking the path of further rotation of the cylindrical body 202 relative to the counter ring 204 (as shown in FIG. 6B ). The spring metal component 209b engages the leading face of the helical path of the cylindrical body 202 and prevents further rotation of the cylindrical body 202 relative to the fixed portion (not shown in FIG. 6B such as the mouthpiece) of the device. This advantageously prevents the device from releasing more liquid medicament after a predetermined number of doses of liquid medicament have been dispensed.

[0093] Third Embodiment

[0094] Reference FIG. 7The dose counter 300 according to the third embodiment of the present application has a spring cage 316 comprising a cylindrical body 302. The cylindrical body 302 is concentrically located within a cylindrical counter ring 304. The cylindrical body 302 is rotatable relative to the counter ring 304. The cylindrical body 302 and the counter ring 304 are concentrically arranged in a housing chassis 305. The housing chassis 305 can form part of a device 51 (not shown in FIG. 7 ) comprising a liquid medicament supply and a mouthpiece for delivering liquid medicament to a patient.

[0095] The first end of the cylindrical counter ring 304 comprises a circumferential drive feature 306. As with the dose counter 100 described above, the circumferential drive feature 306 is defined by a plurality of equally spaced apart toothed protrusions 307 extending from the first end of the counter ring 304. The plurality of toothed protrusions 307 define a series of equally spaced apart gaps 308 therebetween. The plurality of toothed protrusions 307 extend over a majority of the circumference of the first end of the counter ring 304. The dose counter 300 comprises a spring 309a and a rigid locking member 309b which together define a life end lock feature which replaces the elongate tooth portion 109 described above in relation to the first embodiment.

[0096] The spring 309a and the rigid locking member 309b are located in a guide feature 309c which is fixed to a part of the device (not shown in FIG. 7 ) such as the mouthpiece. The spring 309a biases the rigid locking member 309b towards the toothed protrusions 307 of the counter ring 304. The toothed protrusions 307 on the counter ring 304 prevent the rigid locking member 309b from moving at the start of life (i.e. before use of the device) and when the counter is counting during the life of the device (i.e. during use of the device).

[0097] After the dose counter 300 has been shown to be zero, there is a missing toothed protrusion 307 on the counter ring 304. The missing toothed protrusion 307 enables the rigid locking member 309b to be driven by the spring 309a into a locked position in which the rigid locking member 309b blocks the path of rotation of the cylindrical body 302 relative to the fixed part of the device (not shown in FIG. 7 ). The rigid locking member engages the front face of the helical path of the cylindrical body 302 and prevents the cylindrical body 302 from further rotating relative to the fixed part of the device (not shown in FIG. 7 ). This advantageously prevents the device 51 from releasing more liquid medicament after a predetermined number of doses of liquid medicament have been dispensed.

[0098] FIG. 8A and FIG. 8BA cross-sectional view of a dose counter 300 assembled within a soft mist inhaler (SMI) device 51 is provided. The device 51 includes a housing 60, the upper half of which includes a micro pump 15 and a nozzle (not shown in FIG. 8A and FIG. 8B ). The dose counter 300 is fixed in place within the device 51 by the housing 60. FIG. 8A A rigid locking member 309b is shown in a first, unlocked position, above a toothed protrusion 307 on the counter ring 304. FIG. 8B A rigid locking member 309b is shown in a second, locked position, where the rigid locking member 309bb has been biased downward by a spring into a gap defined by a missing toothed protrusion 307 on the counter ring 304.

[0099] Fourth embodiment

[0100] FIG. 9A and FIG. 9B A counter ring 404 according to a fourth embodiment of the present application is shown. The counter ring 404 includes a locking clip 409a attached to the counter ring. The locking clip 409a travels with the counter ring 404 until reaching a position where it collides with the path of the worm gear teeth 426. The worm gear teeth 426 cause one end of the locking clip 409a to bend towards the axis of the cylindrical body 402 (not shown in FIG. 10 and into the path of the engagement feature 430 of the cylindrical body 402, thereby preventing further rotation of the cylindrical body 402 relative to the counter ring 404.

[0101] As shown in FIG. 9B , the locking clip 409a prevents rotation of the cylindrical body 402 because the locking clip 409a remains engaged with the counter ring 404, which in turn remains engaged with the worm gear 420, which is firmly held by a portion of the device (e.g. the mouthpiece) to which the counter ring 404 is assembled. The counter ring 404 can include optional ribs 409b to improve the engagement between the locking clip 409a and the counter ring 404 when in the locked position.

[0102] Fifth embodiment

[0103] Referring to FIG. 10 and FIG. 11 , a dose counter 500 according to a fifth embodiment of the present application has a disc-shaped counter ring 504 having a central cylindrical bore. The dose counter also has a hollow cylindrical body 502 having a first end concentrically located within the central cylindrical bore of the counter ring 504. The cylindrical body 502 is concentrically arranged in a housing chassis 505. The housing chassis 505 can form a portion of a device such as a dry powder inhaler (DPI)FIG. 10 and FIG. 11 The dry powder inhaler (not shown in

[0104] The counter ring 504 includes a circumferential drive feature 506 that extends on the periphery of the circular aperture on the side of the counter ring 504 that faces the hollow cylindrical body 502. In this example, the circumferential drive feature 506 is defined by a plurality of equally spaced teeth 507 that project outwardly from the side of the counter ring 504 that faces the hollow cylindrical body 502. The plurality of teeth 507 define a series of equally spaced gaps 508 therebetween. The side of the counter ring 504 is printed with a numerical indicator that indicates the number of doses of medicament powder that have been dispensed.

[0105] The dose counter 500 also includes a worm 520 that engages both the cylindrical body 502 and the counter ring 504. The worm 520 has a cylindrical shaft 522 and a gear 524. The end of the cylindrical shaft 522 is rotatably mounted in a cylindrical slot 550 in the housing 505. The gear 524 engages the gaps 508 and interfaces with the teeth 507 of the circumferential drive feature 506. The gear 524 extends 360° around the midpoint of the axis of the shaft 522 along a generally helical path and has four teeth 526 that are evenly distributed along the helical path.

[0106] The outer face of the cylindrical body 502 includes three interface features 530a, 530b, 530c that interface with the teeth 526 of the worm 520. In this example, each interface feature 530a, 530b, 530c is a ribbed worm tooth that has a square interface shape (i.e., the cross-section of the ribbed worm tooth is a square shape) and itself extends 120° along a helical path around 1 / 3 of the outer face of the cylindrical body 502. Each interface feature 530a, 530b, 530c experiences a 90° twist as it extends around the outer side of the cylindrical body 502. The twist of the interface features 530a, 530b, 530c helps maintain a close interface between two teeth 526 of the worm 520 as the cylindrical body 502 rotates.

[0107] Referring now to FIG. 12A and FIG. 12B In use, the worm 520 initially interfaces with the first tooth 507a of the circumferential drive feature 506 (as shown in FIG. 12A In use, the worm 520 initially interfaces with the first tooth 507a of the circumferential drive feature 506 (as shown in FIG. 12A and FIG. 12BThe cap opening the mouthpiece of the device can rotate the cylindrical body 502 120° clockwise relative to the counter ring 504, for example, in a dry powder inhaler (DPI) (not shown). When the cylindrical body 502 is rotated 120°, the engagement feature 530a of the cylindrical body 502 drives the gear 524 of the worm 520 to rotate the worm 90°. FIG. 12B A position approximately 60° into the 120° rotation is shown.

[0108] Sixth embodiment

[0109] FIG. 13A and FIG. 13B A disc-shaped body 602 and a worm 620 according to a sixth embodiment of the application are shown. The disc-shaped body 602 has a single engagement feature 630 that extends over the entire perimeter of the disc-shaped body 602. The engagement feature 630 follows a spiral profile. The twist of the engagement feature 630 maintains a close engagement between the two teeth of the worm 620. The disc-shaped body 602 can be used with the counter ring 504 shown in FIG. 10 and FIG. 11 the counter ring 504 shown in to drive the counter ring 504 in different planes.

Claims

1. A dose counter for recording a count of doses dispensed from an inhaler, comprising: a counter ring comprising a circumferential drive feature; a worm comprising a shaft and a gear extending along a helical path about an axis of the shaft to drive the counter ring, wherein the gear comprises one or more recesses distributed along the helical path; a cylindrical body comprising an engagement feature for driving the gear, the engagement feature extending from the cylindrical body along a helical or spiral path to engage the gear such that relative rotational motion between the cylindrical body and the worm rotates the worm about the shaft.

2. The dose counter of claim 1, wherein, a cross-section of the engagement feature normal to the helical or spiral path has an engagement shape configured to fit into each recess of the gear of the worm, wherein as the worm rotates about the shaft, an orientation of the engagement shape changes along the path of the engagement feature such that the engagement shape remains fitted into at least one of the recesses of the gear.

3. The dose counter of claim 2 wherein, the engagement shape is configured to fit tightly into each of the recesses.

4. The dose counter of claim 2 or 3 wherein, the engagement shape is substantially square and the recesses define right-angled corners.

5. The dose counter of any of claims 1 to 3 wherein, the cylindrical body comprises a plurality of engagement features, wherein the engagement features extend along helical or spiral paths that are parallel in rotation.

6. The dose counter of claim 5 wherein, two engagement features are configured to engage the gear simultaneously at at least one location along the helical or spiral path of each of the two engagement features.

7. The dose counter of any of claims 1 to 3 wherein, the helical path of the gear extends less than a full turn about the axis of the shaft.

8. The dose counter of any of claims 1 to 3 wherein, the helical path of the worm extends a full turn or more about the axis of the shaft.

9. The dose counter of any of claims 1 to 3, comprising a housing, wherein the worm is mounted in the housing.

10. The dose counter of claim 9, comprising a locking arm coupled to the housing, the cylindrical body comprising a stop, the locking arm being engageable against the stop to prevent further movement of the cylindrical body.

11. The dose counter of any of claims 1 to 3 wherein, a feature of the counter ring is provided as a release biasing member configured to engage with the cylindrical body to prevent further movement of the cylindrical body.

12. The dose counter of any of claims 1 to 3 wherein, the dose counter comprises a spring metal member and a portion of a periphery of the counter ring comprises a gap for receiving the spring metal member, wherein the spring metal member is provided to move into the gap and into the path of the engagement feature to prevent further movement of the cylindrical body.

13. A dose counter according to any one of claims 1 to 3, comprising a spring and a rigid locking member, wherein, the spring is configured to engage with the engagement feature to prevent further movement of the cylindrical body and the locking member is provided to prevent the spring from disengaging after engagement with the engagement feature.

14. The dose counter of any of claims 1 to 3 wherein, the counter ring comprises a locking clip, wherein the locking clip is provided to be movable by the worm into a position to engage with the engagement feature to prevent further movement of the cylindrical body.

15. The dose counter of any of claims 1 to 3 wherein, the cylindrical body is part of a second housing of the dose counter.

16. The dose counter of any of claims 1 to 3 wherein, the cylindrical body is hollow.

17. The dose counter of any of claims 1 to 3 wherein, the engagement feature extends from an outer surface of the cylindrical body.

18. The dose counter of any of claims 1 to 3 wherein, The counter ring and the cylindrical body have a common axis.

19. The dose counter of any of claims 1 to 3 wherein, The circumferential drive feature of the counter ring comprises regularly spaced teeth or ribs.

20. The dose counter of claim 12 wherein, The circumferential drive feature extends around a portion of the perimeter, and the circumferential drive feature is interrupted by discontinuities in the regular spacing of the teeth or ribs, the discontinuities being in the form of wider gaps or filled gaps.

21. The dose counter of any of claims 1 to 3 wherein, The number of engagement features is in the range 1 to 12.

22. The dose counter of any of claims 1 to 3 wherein, The ratio of angular advancement of the counter ring to angular motion of the cylindrical body is in the range 2:5 to 1 :

200.

23. The dose counter of any of claims 1 to 3 wherein, The dose counter comprises a ratchet, and the ratchet comprises a pawl configured to engage one of the counter ring, the worm and the cylindrical body to prevent reverse rotation of the counter ring.

24. An inhaler comprising a dose counter according to any preceding claim.

25. The inhaler of claim 24, which is a soft mist inhaler (SMI) or a dry powder inhaler (DPI).

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