Dose counter

Abstract

In general, the present invention proposes a dose counter for recording counts of doses dispensed from an inhaler. In one embodiment, a dose counter includes a counter ring that includes a circumferential drive feature. The dose counter also includes a worm including a shaft and a gear extending along a helical path about an axis of the shaft to drive the counter ring. The gear includes recesses uniformly distributed along a helical path. The dose counter also includes a cylindrical body including an engagement feature for driving the gear, the engagement feature extending from the cylindrical body along a helical or spiraling path to engage the gear such that relative rotational movement between the cylindrical body and the worm rotates the worm about its axis.

Description

Technical Field

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

[0002] Patients who use inhalers such as soft mist inhalers (SMIs), pressurized dose inhalers (pMDIs) and dry powder inhalers (DPIs) need to monitor their use of the inhaler. In addition, drug regulatory agencies have begun to require that some method of dose indication be included in the inhaler. Dose counters that provide an accurate count of the number of doses remaining and dose indicators that indicate the proportion of the dose 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 nebulizer, a pressurized dose inhaler or some other type of breast pump). However, despite the progress made, there remains a pressing need for dose counters that are both economical and reliable.

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

[0005] Therefore, there remains a need for an improved dose counter that overcomes the above-mentioned disadvantages.An object of the present invention is to solve at least one of the above-mentioned problems or other problems associated with the prior art. Summary of the invention

[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 also comprises a worm comprising a shaft and a gear extending along a spiral path around the axis of the shaft to drive the counter ring. The gear comprises one or more recesses distributed along the spiral path of the gear. The dose counter also comprises a columnar body comprising an engagement feature for driving a gear, the engagement feature extending from the columnar body along a spiral or spiral path to engage the gear, so that the relative rotational motion between the columnar body and the worm causes the worm to rotate around the shaft.

[0007] In this way, the dose counter can advantageously utilize the rotary motion of the cylindrical body to operate and drive the counter ring. Importantly, this can allow utilizing fewer components to measure the remaining number of inhaler doses. This in turn can advantageously simplify the manufacture of the dose counter. In addition, this dose counter can be suitably used for any situation where the start-up operation of the inhaler will cause some rotary motions, and therefore can be applied to many types of inhalers.

[0008] In some embodiments, the dose counter may include a transmission mechanism for converting the linear or reciprocating motion of the inhaler into the rotational motion of the cylindrical body. This may advantageously enable the cylindrical body to rotate when the activation operation of the inhaler is linear or reciprocating.

[0009] The term "dose counter" as defined herein is taken to include both mechanisms that use a digital count to indicate the number of doses remaining and dose indicating mechanisms that do not count the number of actuations. Such dose indicating mechanisms may, for example, use color coding or other means to indicate the proportion of dose remaining or to indicate that the device is about to end its useful life.

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

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

[0012] In some embodiments, the driving of the counter ring by the worm may be constrained in one direction. For example, the driving of the counter ring by the worm may be constrained in one direction by a ratchet. Suitably, the ratchet may include a pawl configured to engage the counter ring, the worm and / or the cylindrical body to prevent the counter ring from rotating in the opposite direction.

[0013] In some embodiments, the engagement feature may include ribbed worm teeth.

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

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

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

[0017] In some embodiments, the engagement shape can be generally square. For example, the engagement feature can include ribbed worm teeth having a generally square cross-section. In such an embodiment, the recess can define a generally right-angle corner (i.e., a cross-section along the helical path of the gear that is in the form of a right-angle corner). For example, the cross-section of the recess can be generally L-shaped.

[0018] In some embodiments, the engagement shape may be generally triangular. For example, the engagement feature may include a ribbed worm tooth having a generally triangular cross-section. In such an embodiment, the recess may be generally acute (i.e., having a cross-section in the form of a triangular vertex along the helical path of the gear). For example, the cross-section of the recess may be generally <-shaped.

[0019] In some embodiments, the engagement shape may have a generally involute profile.

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

[0021] In some embodiments, the columnar body may include a plurality of engagement features. For example, the columnar body may include two, three, four, five, six, seven, eight, nine or even ten engagement features. In such embodiments, the plurality of engagement features may extend along a spiral or spiral path that rotates in parallel.

[0022] In some embodiments, the cylindrical body may include two engagement features configured to engage the gear simultaneously. For example, the two engagement features may be configured to engage the gear at at least one position on a spiral or spiral path of each of the two engagement features.

[0023] In some embodiments, the helical path of the gear may extend less than a full turn around the axis of the worm's shaft. In some embodiments, the helical path of the gear may extend a full turn around the axis of the worm's shaft.

[0024] In some embodiments, the helical path of the gear may extend one or more full revolutions around the axis of the worm shaft. This may advantageously ensure that engagement is maintained throughout the movement.

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

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

[0027] In some embodiments, the feature of the counter ring can be arranged to release a biasing component or element, which is configured to engage with the cylindrical body to stop the cylindrical body from moving further (e.g., rotating) relative to the counter ring after recording the final dose. This can advantageously stop the cylindrical body from moving further after the dose of the predetermined count has been distributed from the inhaler. Suitably, the feature on the counter ring can include a missing tooth, a filling tooth, or an interruption or a projection protruding from the counter ring. The biasing component or element can include a spring or a stamped metal part. The biasing component or element can be configured to engage with the engagement feature or an engagement feature, or engage with other features of the cylindrical body.

[0028] In some embodiments, the dose counter may include a spring metal component. In this embodiment, a portion of the periphery of the counter ring may include a gap for receiving the spring metal component. Suitably, the spring metal component may be anchored to a part of the inhaler that includes the dose counter, such as a housing or a mouthpiece of the inhaler. In this way, the leading edge of the spring metal component may be arranged to move into the gap and move into the path of the engagement feature. This may stop the columnar body from, for example, moving further (for example rotating) relative to the housing or the mouthpiece after recording the final dose. This may advantageously stop the columnar body from moving further after dispensing a predetermined count of doses from the inhaler.

[0029] In some embodiments, the dose counter can include a spring and a rigid locking component. The spring and the rigid locking component can be appropriately located in the guide feature. The guide feature can be fixed to a part of the inhaler that includes the dose counter, such as 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 the columnar body from, for example, moving further (e.g., rotating) relative to the housing or mouthpiece after recording the final dose. This can advantageously prevent the columnar body from moving further after the dose of the predetermined count has been dispensed from the inhaler. The rigid locking component can be arranged to prevent the spring from disengaging after engaging with the columnar body.

[0030] In some embodiments, the dose counter may include a locking clip. The locking clip may be suitably attached to the counter ring. The locking clip may be arranged to be movable by the worm into a position engaging the engagement feature to prevent further movement of the cylindrical body. For example, the locking clip may be arranged such that engagement of the locking clip with the worm causes the locking clip to move from a first (unlocked) position, in which the locking clip is substantially flush with the counter ring (i.e. substantially in the same plane as the counter ring), thereby causing the locking clip to not block the path of the engagement feature, to a second (locked) position, in which the locking clip is tilted relative to the counter ring, thereby causing the locking clip to block the path of the engagement feature.

[0031] In this way, after the locking clip engages with the worm, the worm may remain fixed in position 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 may be mounted on a fixed part of the housing or mouthpiece. Thus, locking the cylindrical body to the counter ring may prevent further movement (e.g. rotation) of the cylindrical body relative to the housing or mouthpiece after the last dose has been recorded.

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

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

[0034] In some embodiments, the engagement features may 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 around a common axis.

[0036] In some embodiments, the counter ring circumferential drive feature may include regularly spaced teeth or ribs.

[0037] In some embodiments, the circumferential drive feature may extend around a portion of the circumference of the counter ring. Suitably, the circumferential drive feature may be interrupted by discontinuities. For example, where the circumferential drive feature comprises regularly spaced teeth or ribs, the circumferential drive feature may be interrupted by discontinuities located in the regular spacing of the teeth or ribs. Suitably, the discontinuities may be in the form of wider gaps or gap-filling ones.

[0038] In some embodiments, the dose counter may include 1 to 12 engagement features. For example, the dose counter may include 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 cylindrical 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 invention provides an inhaler (ie an inhalation device) comprising a dose counter according to the first aspect of the present invention.

[0041] In some embodiments, the inhaler can be suitably configured to aerosolize a pharmaceutical liquid. For example, the inhaler can be a soft mist inhaler (SMI).

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

[0043] Throughout the description and claims of this specification, the words "comprise" and "comprising" and variations of these words, such as "having" and "containing", mean "including but not limited to", and do not exclude other components, integers or steps. In addition, unless the context requires otherwise, the singular encompasses the plural: in particular, where the indefinite article is used, the specification is to be understood as contemplating both plural and singularity, unless the context requires otherwise.

[0044] Preferred features of each aspect of the invention may be described in conjunction with any other aspect. Within the scope of this application, it is expressly intended that the various aspects, embodiments, examples and alternatives set forth in the preceding paragraphs, claims and / or the following description and drawings, and in particular the individual features therein, may be employed independently or in any combination. That is, all embodiments and / or features of any embodiment may be combined in any manner and / or combination, unless such features are incompatible. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0046] Figure 1AA perspective view of a dose counter according to a first embodiment of the invention, viewed from above and from one side, is shown, the dose counter having a hollow cylindrical body concentrically located within a cylindrical counter ring, the cylindrical body and the counter ring being concentrically arranged in a housing chassis and rotatable relative to each other, the first end of the cylindrical counter ring comprising a circumferential drive feature having a plurality of equally spaced tooth-like projections extending from the first end of the counter ring, a worm being meshed to the cylindrical body and the counter ring, the worm having a cylindrical shaft. The end of the cylindrical shaft is rotatably mounted in a generally cylindrical slot in the housing.

[0047] Figure 1B Shows Figure 1A A side cross-sectional view of a dose counter in FIG.

[0048] Figure 1C Shows Figure 1A A top view of a dose counter in FIG.

[0049] Figure 1D Shows Figure 1A Side view of the dose counter in the locked position;

[0050] Figure 2A Shows Figures 1A to 1D A three-dimensional view of the cylindrical body in FIG.

[0051] Figure 2B Shows Figures 1A to 1D A side view of a cylindrical body in FIG.

[0052] Figure 3 Shows Figures 1A to 1D A stereogram of the worm in ;

[0053] Figure 4A Shows Figures 1A to 1D A side view of the dose counter in FIG. 1 before the cylindrical body is rotated relative to the counter ring;

[0054] Figure 4B Shows Figure 4A A side view of the dose counter in FIG. 1 after the cylindrical body is rotated 90 degrees counterclockwise;

[0055] Figure 4C Shows Figure 4B A side view of the dose counter in FIG. 1 after the cylindrical body is further rotated 90 degrees clockwise;

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

[0057] Figure 5B Shows Figure 5BA partial cross-sectional view of a soft mist inhaler (SMI) device in FIG. 1 , the partial cross-sectional view showing a spring cap engaged with a spring retainer;

[0058] Fig. 6A shows a perspective view of a dose counter according to a second embodiment of the invention, the dose counter in this embodiment being similar to the dose counter in the first embodiment and having a sprung metal locking member which is shown in an unlocked position;

[0059] Figure 6B Shows Fig. 6A A perspective view of a dose counter in FIG. 1 , the spring metal locking member is shown in a position where the locking member is released by the dose counter before locking occurs;

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

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

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

[0063] Fig.9A shows a perspective view of a counter ring and an end-of-life clip according to a fourth embodiment of the present invention, the counter ring and the end-of-life clip being shown in an unlocked position;

[0064] Fig. 9B Shows Fig.10 A is a perspective view of the counter ring and end-of-life clip in the locked position;

[0065] Fig.10 shows a perspective view of a dose counter according to a fifth embodiment of the invention, the dose counter having a disc-shaped counter ring with a central cylindrical hole and having a hollow cylindrical body, a first end of the hollow cylindrical body being concentrically located within the central cylindrical hole of the counter ring, the cylindrical body being concentrically arranged in a housing chassis forming part of a device such as a dry powder inhaler, the cylindrical body and the counter ring each being independently rotatable relative to the housing chassis, the outer face of the cylindrical body comprising three engagement features for engagement with teeth of a worm, each engagement feature comprising a ribbed worm tooth having a square engagement shape;

[0066] Fig.11 Shows Fig.10 An exploded view of the dose counter in ;

[0067] Fig. 12A Shows Fig.10 A side cross-sectional view of a dose counter in FIG. 1 before the cylindrical body is rotated relative to the engagement feature;

[0068] Fig. 12B Shows Figure 7 A is a side cross-sectional view of the dose counter after the cylindrical body is rotated 60 degrees counterclockwise;

[0069] Fig.13A shows a top view of a cylindrical body and a worm according to a sixth embodiment of the present invention; and

[0070] Fig. 13B Shows Fig.13A A three-dimensional diagram of the cylindrical body and the worm. DETAILED DESCRIPTION

[0071] First embodiment

[0072] With reference to FIG1 , a dose counter 100 according to a first embodiment of the present invention comprises a hollow cylindrical body 102 concentrically located within a cylindrical counter ring 104. The cylindrical body 102 can rotate relative to the counter ring 104. The cylindrical body 102 and the counter ring 104 are concentrically arranged in a housing chassis 105. The housing chassis 105 may form part of a device such as a soft mist inhaler (SMI) (not shown in FIG1 ) that includes a liquid drug supply and a mouthpiece for delivering the liquid drug to a patient. The cylindrical body 102 and the counter ring 104 can each rotate independently relative to the housing chassis 105.

[0073] The first end of the cylindrical counter ring 104 includes a circumferential drive feature 106. In this example, the circumferential drive feature 106 is defined by a plurality of equally spaced teeth 107 extending from the first end of the counter ring 104. The plurality of teeth 107 define a series of equally spaced gaps 108 therebetween. The plurality of teeth 107 extend over a majority of the circumference of the first end of the counter ring 104. The counter ring 104 has an outer face printed with a numerical indicator. The outer face printed with the numerical indicator indicates the number of doses of liquid medication that have been dispensed.

[0074] The dose counter 100 also includes a worm 120 meshing with both the cylindrical body 102 and the counter ring 104. The worm 120 has a cylindrical shaft 122 and a gear 124. The end of the cylindrical shaft 122 is rotatably mounted in a generally cylindrical slot 150 in the housing 105. The gear 124 meshes into the gap 108 and engages with the toothed protrusion 107 of the 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 face of the cylindrical body 102 includes a pair of engagement features 130a, 130b that engage 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 in shape) and extending 180° along a spiral path around opposite sides of the outer face of the cylindrical body 102. Each engagement feature 130a, 130b undergoes a 90° twist as it extends around the outer side of the cylindrical body 102. The twist of the engagement features 130a, 130b maintains tight engagement between two adjacent teeth in the teeth 126 of the worm 120 as the cylindrical body 102 rotates.

[0076] Figure 1B and Figure 1C A side cross-sectional view and a top view of the dose counter 100 are provided, respectively.

[0077] Figure 1D A side view of a dose counter 100 is provided. Figure 1D As shown in FIG, a portion of the periphery of the counter ring 104 is provided with an elongated tooth portion 109 which does not have any gap and defines an end-of-life locking feature. Figure 1D In the embodiment of the present invention, the worm 120 is shown abutting the elongated toothed portion 109, which prevents the cylindrical body 102 from rotating further counterclockwise relative to the counter ring 104. In use, this allows the dose counter 100 to be intentionally jammed. When the dose counter 100 is assembled in a soft mist inhaler (SMI) containing liquid medicament, this can advantageously prevent the inhaler from releasing more liquid medicament after a predetermined number of liquid medicament doses have been dispensed.

[0078] Figure 2A and Figure 2B A perspective view and a side view of the columnar body 102 are provided respectively, and Figure 3 A perspective view of the worm 120 is provided.

[0079] Reference now FIG. 4A to FIG. 4C In use, the worm 120 is initially engaged between the first and second teeth 107a, 107b of the circumferential drive feature 106 (eg, Figure 4ATo use a device including a dose counter 100 ( FIG. 4A to FIG. 4C In an inhaler (not shown), such as a soft mist inhaler (SMI), the patient rotates the base portion of the device 180° counterclockwise to provide a dose of medication from the device through the mouthpiece of the device.

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

[0081] Figure 4C The dose counter 100 is shown after the base portion, and therefore the cylindrical body 102, has been rotated a further 90 degrees counter-clockwise (a total of 180 degrees).

[0082] Because the increments of rotation are small, the outer surface of the counter ring 104 is printed with numbers displayed in increments of 5, 10 or 20 to allow the patient to determine the remaining number of doses. For options with lower gear ratios (such as gear ratios in the range of 2:5 to 1:30), printing individual numbers (i.e., 1, 2, 3) is feasible.

[0083] Figure 5A A cross-sectional view of a dose counter 100 when assembled within a soft mist inhaler (SMI) device 1 is provided. The device 1 comprises a housing 10, the lower half of which houses a cartridge 12 containing a liquid drug. The upper half of the housing 10 comprises a spring retainer 16. The spring retainer 16 is located directly above the cartridge 12. The dose counter 100 is held in place by the housing 10 concentrically around the spring retainer 16. The spring cap 14 and the coil spring ( Figure 5A The spring cap 14 is an annular member located at the upper end of the spring holder 16. The conduit 22 fluidly connects the cartridge 12 to the mouthpiece 30 of the device 1. The conduit 22 passes through the center of the spring cap 14 and the coil spring.

[0084] The lowermost end of the housing 10 is attached to a base portion 40 that can rotate relative to the upper half of the housing 10. Rotating the base portion 40 180° clockwise relative to the upper half of the housing 10 forces the cartridge 12 to move downward, thereby compressing the coil spring 17 and drawing a predetermined volume of liquid drug from the cartridge 12 through the conduit 22 and out through the micro pump 15 located inside the mouthpiece 30. After the device is actuated, the liquid drug is discharged from the micro pump 15 and the device 1, and then the coil spring is no longer compressed and the cartridge 12 returns to its original position. The spring cap 14 is aligned with the spring retainer 16 in a rotatable manner to prevent undesirable torque from being transmitted to the device mechanism during actuation of the device 1.

[0085] Figure 5B FIG. 1 is a partial cross-sectional view of the dose counter 100 when assembled in a soft mist inhaler (SMI) device 1, which shows the spring cap 14 engaged with the spring retainer 16. The spring cap 14 has a plurality of protruding ribs ( Figure 5B These protruding ribs engage with grooves 18 provided in the spring retainer 16 and extend in the grooves.

[0086] The base portion 40 is connected to the cylindrical body 102 of the dose counter 100 such that a 180° clockwise rotation of the base portion 40 causes the cylindrical body 102 to rotate 180° clockwise relative to the counter ring 104. When the cylindrical body 102 rotates 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] The slot 44 in the housing allows a digital indicator printed on the outside of the counter ring 104 to be read through the housing. In this example, the digital indicator indicates the number of doses of liquid drug that have been dispensed from the device 1.

[0088] Second embodiment

[0089] refer to Fig. 6A The dose counter 200 according to the second embodiment of the present invention has substantially the same structure as the dose counter 100 of the first embodiment described above, and has a hollow cylindrical body 202 concentrically located within a cylindrical counter ring 204. The cylindrical body 202 can rotate 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 may form part of a device such as a soft mist inhaler (SMI) ( Fig. 6A ), the soft mist inhaler comprises a liquid medicine supply and a mouthpiece for delivering the liquid medicine 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 invention, the circumferential drive feature 206 is defined by a plurality of equally spaced tooth-like projections 207 extending from the first end of the counter ring 204. The plurality of tooth-like projections 207 define a series of equally spaced gaps 208 therebetween. The plurality of tooth-like projections 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 locking feature that replaces the elongated tooth portion 109 described above in relation to the first embodiment.

[0091] The spring metal component 209 is anchored to a portion of the device ( Fig. 6A At the beginning of life (ie before use of the device) and while the dose counter 200 is counting throughout its life (ie during use of the device), the spring metal part 209b is held in a diametric position by the plurality of tooth-like protrusions 207.

[0092] After the dose counter 200 displays zero, the leading edge of the spring metal component 209b moves into the gap 209a in the diametrical direction, thereby blocking the path of further rotation of the cylindrical body 202 relative to the counter ring 204 (eg, Figure 6B The spring metal part 209b engages with the front of the spiral path of the columnar body 202 and prevents the columnar body 202 from moving relative to the fixed part of the device ( Figure 6B This advantageously prevents the device from releasing more liquid drug after a predetermined number of liquid drug doses have been dispensed.

[0093] Third embodiment

[0094] refer to Figure 7 , a dose counter 300 according to a third embodiment of the invention has a spring holder 316 comprising a cylindrical body 302. The cylindrical body 302 is concentrically located within a cylindrical counter ring 304. The cylindrical body 302 can rotate 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 may form part of a device 51, such as a soft mist inhaler (SMI) ( Figure 7 ), the soft mist inhaler comprises a liquid medicine supply and a mouthpiece for delivering the liquid medicine to a patient.

[0095] The first end of the cylindrical counter ring 304 includes 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 teeth 307 extending from the first end of the counter ring 304. The plurality of teeth 307 define a series of equally spaced gaps 308 therebetween. The plurality of teeth 307 extend over a majority of the circumference of the first end of the counter ring 304. The dose counter 300 includes a spring 309a and a rigid locking member 309b which together define an end-of-life locking feature that replaces the elongated teeth 109 described above with respect to the first embodiment.

[0096] The spring 309a and the rigid locking member 309b are located in a portion fixed to the device ( Figure 7 The spring 309a biases the rigid locking member 309b toward the toothed protrusion 307 of the counter ring 304. The toothed protrusion 307 on the counter ring 304 prevents the rigid locking member 309b from moving at the beginning of life (i.e., before using the device) and when the counter counts throughout the life (i.e., during use of the device).

[0097] After the dose counter 300 displays 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 cylindrical body 302 from being moved relative to the fixed part ( Figure 7 The rigid locking member engages with the front of the spiral path of the columnar body 302 and prevents the columnar body 302 from rotating relative to the fixed part (not shown) of the device. Figure 7 This advantageously prevents the device 51 from releasing more liquid drug after a predetermined number of liquid drug doses have been dispensed.

[0098] Fig. 8A and Figure 8B A cross-sectional view of a dose counter 300 assembled within a soft mist inhaler (SMI) device 51 is provided. The device 51 comprises a housing 60, the upper half of which comprises a micro pump 15 and a nozzle (in Fig. 8A and Figure 8B The dose counter 300 is fixed in place within the device 51 by the housing 60. Fig. 8A The rigid locking member 309 b is shown in a first, unlocked position, positioned over the toothed protrusion 307 on the counter ring 304 . Figure 8BThe rigid locking member 309 b is shown in a second locked position, wherein the rigid locking member 309 bb has been spring biased downwardly into the gap defined by the missing tooth-like protrusion 307 on the counter ring 304 .

[0099] Fourth embodiment

[0100] Fig.9A and Fig. 9B 4 shows a counter ring 404 according to a fourth embodiment of the present invention. 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 it reaches 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 move toward the axis ( Fig.10 A and Fig.10 B) bends and enters 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] like Fig. 9B , the locking clip 409a prevents the cylindrical body 402 from rotating because the locking clip 409a remains engaged with the counter ring 404, which in turn remains engaged with the worm gear 420, and the worm gear 420 is securely held by a portion of the device (e.g., a mouthpiece) in which the counter ring 404 is assembled. The counter ring 404 may include an optional rib 409b to improve the engagement between the locking clip 409a and the counter ring 404 when in the locked position.

[0102] Fifth embodiment

[0103] refer to Fig.10 and Fig.11 The dose counter 500 according to the fifth embodiment of the present invention has a disc-shaped counter ring 504 having a central cylindrical hole. The dose counter also has a hollow cylindrical body 502, the first end of which is concentrically located in the central cylindrical hole of the counter ring 504. The cylindrical body 502 is concentrically arranged in a housing chassis 505. The housing chassis 505 may form part of a device such as a dry powder inhaler (DPI) ( Fig.10 and Fig.11 ), the dry powder inhaler includes a drug powder supply and a mouthpiece for delivering the drug powder to the patient. The cylindrical body 502 and the counter ring 504 can each rotate independently relative to the housing chassis 505.

[0104] The counter ring 504 includes a circumferential drive feature 506 extending around the periphery of the circular aperture on the side of the counter ring 504 facing the hollow cylindrical body 502. In this example, the circumferential drive feature 506 is defined by a plurality of equally spaced tooth-like protrusions 407 that protrude outwardly from the side of the counter ring 504 facing the hollow cylindrical body 502. The plurality of tooth-like protrusions 507 define a series of equally spaced gaps 408 therebetween. A numerical indicator is printed on one side of the counter ring 504 indicating the number of doses of medicament powder dispensed.

[0105] The dose counter 500 also includes a worm 520 meshing with 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 meshes with the gap 508 and engages with the toothed protrusion 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 evenly distributed along the helical path.

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

[0107] Reference now Fig. 12A and Fig. 12B In use, the worm 520 is initially engaged with the circumferential drive feature 506 (eg Fig. 12A In order to use the device (shown in FIG. 500 ) comprising the dose counter 500 Fig. 12A and Fig. 12B In a device such as a dry powder inhaler (DPI), opening the cover of the mouthpiece of the device can cause the cylindrical body 502 to rotate 120° clockwise relative to the counter ring 504. When the cylindrical body 502 rotates 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 of approximately 60° out of a 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 present invention are shown. The disc-shaped body 602 has a single engagement feature 630 that extends over the entire periphery of the disc-shaped body 602. The engagement feature 630 follows a spiral profile. The twisting of the engagement feature 630 maintains a tight engagement between the two teeth of the worm 620. The disc-shaped body 602 can be Fig.10 and Fig.11 The counter ring 504 shown in FIG. 5 is used together with the counter ring 504 to drive the counter ring 504 in different planes.

Claims

1. A dose counter (100) for recording a count of doses dispensed from an inhaler, comprising: a counter ring (104) including a circumferential drive feature (106); a worm (120) comprising a shaft (122) and a gear (124) extending along a helical path around the axis of the shaft (122) to drive the counter ring (104), wherein the gear (124) comprises one or more recesses distributed along the helical path; A cylindrical body (102) includes an engagement feature (130a, 130b) for driving the gear (124), the engagement feature extending from the cylindrical body (102) along a spiral or spiral path to engage the gear (124), so that relative rotational movement between the cylindrical body (102) and the worm (120) causes the worm to rotate about the axis (122).

2. The dose counter of claim 1, wherein: A cross-section of the engagement feature orthogonal to the spiral 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 axis, the orientation of the engagement shape changes along the path of the engagement feature so 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. A dose counter according to claim 2 or 3, wherein: The engagement shape is generally square, and the recess defines right-angled corners.

5. A dose counter according to any one of the preceding claims, wherein: The cylindrical body includes a plurality of engagement features extending along parallel rotating helical or spiral paths.

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

7. A dose counter according to any preceding claim, wherein: The helical path of the gear extends less than one full revolution around the axis of the shaft.

8. A dose counter according to any preceding claim, wherein: The helical path of the worm extends one or more full revolutions around the axis of the shaft.

9. A dose counter according to any preceding claim, comprising a housing in which the worm is mounted.

10. A dose counter according to claim 9 including a locking arm coupled to the housing, the cylindrical body including a stop against which the locking arm is engageable to prevent further movement of the cylindrical body.

11. A dose counter according to any one of claims 1 to 9, wherein: The features of the counter ring are configured to release a biasing member configured to engage the cylindrical body to prevent further movement of the cylindrical body.

12. A dose counter according to any one of claims 1 to 9, wherein: The dose counter includes a spring metal component, and a portion of the periphery of the counter ring includes a gap for receiving the spring metal component, wherein the spring metal component is arranged to move into the gap and into the path of the engagement feature when the spring metal component is aligned with the gap to prevent further movement of the cylindrical body.

13. A dose counter according to any one of claims 1 to 9, 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 component is configured to prevent the spring from disengaging after engaging with the engagement feature.

14. A dose counter according to any one of claims 1 to 9, wherein: The counter ring includes a locking clip, wherein the locking clip is configured to be movable by the worm screw into a position engaging the engagement feature to prevent further movement of the cylindrical body.

15. A dose counter according to any one of claims 1 to 7, wherein: The cylindrical body is part of a second housing of the dose counter.

16. A dose counter according to any preceding claim, wherein: The cylindrical body is hollow.

17. A dose counter according to any preceding claim, wherein: The engagement feature extends from an outer surface of the cylindrical body.

18. A dose counter according to any preceding claim, wherein: The counter ring and the cylindrical body have a common axis.

19. A dose counter according to any preceding claim, wherein: The circumferential drive feature of the counter ring comprises regularly spaced teeth or ribs.

20. The dose counter of claim 18, wherein: The circumferential drive feature extends around a portion of the periphery and is interrupted by discontinuities in the regular spacing of the teeth or ribs, the discontinuities being in the form of wider gaps or gap-filling gaps.

21. A dose counter according to any preceding claim, wherein: The number of engagement features is in the range of 1 to 12.

22. A dose counter according to any preceding claim, wherein: The ratio of the angular advancement of the counter ring to the angular movement of the cylindrical body is in the range of 2:5 to 1:

200.

23. A dose counter according to any preceding claim, wherein: The dose counter includes a ratchet, and the ratchet includes 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. An inhaler according to claim 24, wherein The inhaler is either a soft mist inhaler (SMI) or a dry powder inhaler (DPI).

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