HK1219066B - Dose counters for inhalers, inhalers and shafts thereof - Google Patents

Description

Dose counter for inhaler, inhaler and shaft thereof

This application is a divisional application of the Chinese patent application with international application number PCT/EP2011/002462, national application number 201180024350.6, application date May 18, 2011, and titled “Dose counter for inhaler, inhaler and shaft thereof”.

Technical Field

The present invention relates to a dose counter for an inhaler, an inhaler and a shaft thereof, and a method of assembling the same. The present invention is particularly applicable to metered dose inhalers, including dry powder inhalers, breath-actuated inhalers, and manually operated metered dose inhalers.

Background Art

Metered dose inhalers can include a pressurized canister that holds a mixture of an active drug and a propellant. Such canisters are typically formed from a deep-drawn aluminum cup with a crimped lid that carries a metering valve assembly. The metering valve assembly is provided with a protruding valve stem that, during use, acts as a push-fit member to be inserted into a valve stem seat in the actuator body of the inhaler having a drug delivery outlet. To activate the manually operable inhaler, the user applies a compressive force to the closed end of the canister by hand. The internal components of the metering valve assembly are spring-loaded, requiring approximately 15 to 30N of compressive force to activate the device in typical cases. In response to this compressive force, the canister moves axially relative to the valve stem, and this axial movement is sufficient to actuate the metering valve and cause the metered amount of drug and propellant to be pushed through the valve stem. This is then released into the mouthpiece of the inhaler through a nozzle in the valve stem seat, allowing the user, who inhales through the inhaler outlet, to receive a metered dose of the drug.

A disadvantage of self-administration of inhalers is that it is difficult to determine how much active drug and/or propellant remains in the inhaler (especially active drug), if any, and this is potentially dangerous for the user as dosage becomes unreliable and backup devices are not always available.

Thus, inhalers comprising a dose counter have become known.

WO 98/280733 discloses an inhaler having a ratchet mechanism for driving a belt-driven dose counter. The shaft onto which the belt is wound has a friction clutch or spring to prevent reverse rotation of the shaft.

EP-A-1486227 discloses an inhaler for dry powder medicaments having a ratchet mechanism for a dose counter that is operated when the mouthpiece of the inhaler is closed. Due to the manner in which the mouthpiece is opened and closed, the actuating pawl of the device, which is mounted on a yoke, travels a long, known, and consistent length when opening and closing the mouthpiece.

WO 2008/119552 discloses a metered dose inhaler suitable for breath-operated applications and operating with a known and constant canister stroke length of 3.04 mm +/- 0.255 mm. A storage reel from which a counter is unwound rotates on a shaft having a cotter pin intended to keep the storage reel taut.

Recently, it has become desirable to further improve dose counters, and in particular, it has been found that extremely accurate dose counters are provided for manually operated canister-type metered dose inhalers. Unfortunately, in the process of making the present invention, it has been found that in these inhalers, the stroke length of the canister in use is largely controlled by the user's operation on each dose. Therefore, the stroke length is highly variable, and it has been found that it is extremely difficult to provide highly reliable dose counters for these applications. When the canister is not released, the dose counter must not count the dose, because this may mistakenly indicate that the user's dose has been applied, and if this is done repeatedly, the user will throw away the canister or the entire device before the real time of replacing the device. In addition, the canister must not be released when the dose counter is not counting, because the user may think that the canister has not yet been released and subsequently apply another dose, and if this is done repeatedly, the active drug and/or propellant may run out, and the user may think that the device is still suitable for use according to the counter. It has also been found that it is quite difficult to assemble some known inhaler devices and the dose counters used for them. In addition, it would be desirable to improve the inhaler by making them easily usable after being washed with water. Some dose counters may not keep a particularly reliable count, for example if they are dropped onto a hard surface.

Summary of the Invention

The present invention is directed to alleviating, at least to some extent, one or more problems of the prior art.

According to a first aspect of the present invention, there is provided a dose counter for a metered dose inhaler having a body arranged to hold a medicament canister in a predetermined configuration for movement relative to the body; the dose counter comprising:

An incremental counting system for counting doses, the incremental counting system having a body; an actuator, the actuator being arranged to be driven in response to a canister movement and to drive an incremental output member in response to the canister movement, the actuator and the incremental output member being configured to have a predetermined canister release configuration and a counting configuration in a canister release sequence, the canister release configuration being determined by the position of the actuator relative to a reference, the canister releasing the medicament in the canister release configuration, and the counting configuration being determined by the position of the actuator relative to the reference, the incremental counting system making incremental counts in the counting configuration, wherein the actuator is arranged to reach the position of the actuator in the counting configuration at or after the position of the actuator in the canister release configuration.

It has been found that this arrangement is highly advantageous, and this is owing to it provides very accurate dose counter, and this dose counter is applicable to the metered dose inhaler of manual operation.It has been found that the dose counter with these features has the failure rate of pressing 50 failure counts less than per million complete canisters start.In making process of the present invention, unexpectedly found that, can realize highly reliable counting by dose counter at the point that canister discharges or counting soon after this.The inventor has found, release the momentum and the motion related in this canister, and in certain embodiments, the reduction slightly in the canister back pressure on the user when canister discharges, can very reliably cause the other further motion through counting point.

The actuator and incremental counting system can be arranged so that the actuator is displaced less than 1 mm relative to the body between its positions in the counting and release configurations, typically 0.25 to 0.75 mm, more preferably about 0.4 to 0.6 mm, with about 0.48 mm being preferred. A canister that can move substantially in unison with the actuator can reliably move this additional distance to achieve very reliable counting.

The incremental counting system may comprise a ratchet mechanism, and the incremental output member may comprise a ratchet wheel having a plurality of circumferentially spaced teeth arranged to engage the actuator.

The actuator may include an actuating pawl arranged to engage the teeth of the ratchet. The actuating pawl may be arranged to be connected to or integral with an actuator pin, which is arranged to engage and be depressed by a flange at the bottom of the medication canister. The actuating pawl may be substantially U-shaped, having two parallel arms arranged to pull on a central pawl member arranged substantially perpendicular to the arms. This provides a highly reliable actuating pawl that can reliably pull the teeth of the ratchet.

The incremental counting system may comprise a tape counter having a tape with incremental dose markings located thereon, the tape being arranged on a tape storage spool and arranged to be unwound therefrom.

The actuator and incremental output member can be arranged to provide: a start configuration in which the actuator is spaced apart from the ratchet output member; a reset configuration in which the actuator is engaged with the incremental output member during a tank release sequence; and an end configuration in which the actuator is disengaged from the ratchet output member during a tank release sequence.

When in the start configuration, the actuator may be arranged to be positioned approximately 1.5 to 2.0 mm from its position in the release configuration, with approximately 1.80 mm being preferred.

When in the reset configuration, the actuator may be arranged to be positioned approximately 1.0 to 1.2 mm from its position in the release configuration, with approximately 1.11 mm being preferred.

When in the end configuration, the actuator may be arranged to be positioned approximately 1.1 to 1.3 mm from its position in the release configuration, with approximately 1.18 mm being preferred.

These arrangements provide very reliable dose counting, particularly in the case of manually operated canister-type metered dose inhalers.

The body may include a structure for urging the actuator to disengage the incremental output member when the actuator passes through the end configuration. The structure may include a raised portion of an otherwise substantially straight surface on which the actuator engages and is arranged to slide along the surface during a canister release sequence.

The dose counter may comprise a counting pawl having teeth arranged to engage the incremental output member, the teeth and incremental output member being arranged to allow only unidirectional incremental relative movement therebetween. When the incremental output member comprises a ratchet, the teeth may therefore act as anti-backward drive teeth for the ratchet, thereby allowing only unidirectional movement or rotation of the ratchet.

The counting pawl may be substantially fixedly mounted on the body of the incremental counting system and may be arranged to repeatedly engage equally spaced teeth of the incremental output member in an anti-back drive interlock configuration when the counter is operated. The counting pawl may be positioned so that, when the actuator and the incremental output member are in their end configurations, the incremental output member moves halfway, or substantially halfway, from one anti-back drive interlock configuration to the next anti-back drive interlock configuration. This is highly advantageous because it minimizes the risk of the dose counter double counting or non-counting.

According to a further aspect of the invention there is provided an inhaler comprising a body arranged to hold a medicament canister in a predetermined configuration; and a dose counter mounted in the body, the dose counter being as set out in at least one other aspect of the invention.

The inhaler body may include a canister receiving portion and a separate counter chamber, the dose counter being located within the body thereof, the incremental output member and its actuator being within the counter chamber, the inhaler body having a wall surface separating the canister receiving portion and the counter chamber, the wall surface being provided with a communicating hole, the actuating member extending through the communicating hole so that movement of the canister is transmitted to the actuator.

According to another aspect of the present invention, a kind of inhaler for metered dose inhalation is provided, this inhaler comprises: main body, described main body has tank shell, described tank shell is arranged to hold medicament tank so that medicament tank moves in tank shell; And dose counter, described dose counter has actuating member, at least a part of described actuating member is positioned in described tank shell so that by the movement of medicament tank and operates, wherein described tank shell has inner wall and the first inner wall tank support structure positioned adjacent to described actuating member.This is highly advantageous, because the first inner wall tank support structure can prevent jar from excessively swinging relative to the main body of inhaler.Because this jar can operate the actuating member of dose counter, this significantly improves dose counting and avoids counter error.

The canister housing may have a longitudinal axis passing through a central outlet port thereof, the central outlet port being arranged to cooperate with an external canister release lever of a medicament canister, the inner wall canister support structure, the actuation member and the outlet port being located in a common plane coinciding with the longitudinal axis. This configuration may therefore prevent the canister from swinging towards the position of the dose counter actuation member, thereby minimizing errors in counting.

The tank housing may have an additional inner tank wall support structure located on the inner wall opposite or substantially opposite the actuating member. Thus, the tank may be supported against rocking motion away from the actuating member to minimize counting errors.

The tank shell may be substantially straight and tubular and may have an arrangement in which each of the inner wall support structures comprises a rail extending longitudinally along the inner wall.

Each of the rails may be stepped, wherein it may have: a first portion positioned toward the drug outlet end or the valve stem seat of the canister housing, the first portion extending inwardly a first distance from the main surface of the inner wall; and a second portion positioned toward the opposite end of the canister chamber, the second portion extending inwardly a second, smaller distance from the main surface of the inner wall. Thus, this may facilitate insertion of the canister into the canister housing so that the canister can be gradually aligned in a stepwise manner as it is inserted into the canister housing.

The inhaler may include further canister support rails spaced about the inner periphery of the inner wall of the canister housing and extending longitudinally thereof.

At least one of the further rails may extend inwardly from a major surface of the inner wall a constant distance.

At least one of the further rails may be formed with a similar configuration as the first inner wall tank support structure.

The dose counter may be located in a counter chamber separate from the canister housing, except for the at least part of the actuation member, the actuation member comprising a pin extending through a hole in a wall separating the counter chamber from the canister housing.

According to another aspect of the present invention, there is provided an inhaler for inhaling a medicament, the inhaler comprising:

A body for holding a medicament reservoir; the body comprising a dose counter having a movable actuator and a return spring for the actuator, the return spring having a substantially cylindrical and annular end; the body having a support structure therein for supporting the end of the return spring, the support structure comprising a shelf to which the end can be engaged and a recess below the shelf.

This shelf and groove arrangement is highly advantageous since it allows a tool, such as manual or mechanical tweezers, to be used to place the actuator's return spring onto the shelf, the tool subsequently being withdrawn at least partially through the groove.

The shelf may be U-shaped.

The support structure may comprise a U-shaped upright wall extending around the U-shaped frame, the frame and upright wall thereby forming a stepped riser of a step-like arrangement.

The groove below the shelf may also be U-shaped.

At least one chamfered surface may be provided at the entrance to the shelf. This may facilitate insertion of the actuator and return spring into position.

Another aspect of the present invention provides a method for assembling an inhaler, the method comprising the steps of positioning the end of the spring on the frame with the aid of an assembly tool and subsequently withdrawing the assembly tool at least partially through the recess. This assembly method is highly advantageous compared to prior art methods, in which spring insertion is difficult and withdrawal of the tool sometimes inadvertently withdraws the spring.

The cylindrical and annular end of the spring can be moved into the holder while being positioned on the holder in a direction transverse to its cylindrical extension.

According to a further aspect of the invention, there is provided an inhaler for inhaling a medicament, the inhaler having a body for holding a medicament reservoir; and a dose counter having a movable actuator and a chassis mounted on the body; the chassis being heat-fixed in position on the body.

This is highly advantageous as the chassis can be very accurately arranged and securely held in position, thereby further improving counting accuracy compared to prior art arrangements where some movement of the chassis relative to the body may be tolerated in the snap connection.

The chassis may have at least one of a pin or hole heat-secured to a corresponding hole or pin of the body.

The chassis may have a ratchet counter output member mounted thereon.

The ratchet counter output member may comprise a ratchet wheel arranged to incrementally wind up a dose meter tape on which dose indicia are located.

According to a further aspect of the present invention, there is provided a method of assembling an inhaler according to the aforementioned aspect of the present invention, the method comprising the step of: heat-fixing the chassis to the body. The heat-fixing step is highly advantageous in that the chassis is fixedly arranged to the body so as to achieve highly accurate dose counting in the assembled inhaler.

The assembly method may include installing a spring return ratchet actuator in the body prior to heat fixing the chassis in place.

The method may comprise pre-assembling the chassis with a dose meter tape prior to the step of heat fixing the chassis in position.

The method may include attaching a dose meter cover to the body after the heat fixing step.The cover may be welded to the body, or in some embodiments may be glued or otherwise attached in place.

According to a further aspect of the invention, there is provided an inhaler for inhaling a medicament and having a body having: a main portion thereof for holding a medicament reservoir; and a dose counter located in a dose counter chamber of the body, the dose counter chamber being separate from the main portion of the body, the dose counter chamber of the body having a dose display device and being perforated to allow water or a water-containing substance in the dose counter chamber to evaporate into the atmosphere.

This is highly advantageous as it enables the inhaler to be thoroughly washed and the dose counting chamber to be fully dried thereafter.

The display device may include a mechanical counter display device within the dose counter chamber and a window for viewing the mechanical counter display device. The mechanical counter display device may include a belt. The perforated dose counter chamber thus allows for reliable washing of the inhaler (if desired, by the user) and thus allows for drying without fogging of the display device window.

The dose counter chamber may be perforated with a discharge hole formed through the outer wall of the body. The discharge hole may be located at a bottom portion of the body of the inhaler, thereby facilitating adequate discharge of the inhaler when the inhaler is in an upright position after washing.

According to a further aspect of the invention there is provided a dose counter for an inhaler, the dose counter having a display tape arranged to be incrementally driven from a tape storage spool onto an incremental tape take-up drive shaft, the spool having an inner bore supported by and for rotation about a support shaft, at least one of the bore and the support shaft having a protrusion resiliently biased into frictional engagement with the other of the bore and the support shaft by longitudinally extending mutual frictional interaction.

This arrangement may provide good friction for the spool, thereby improving the accuracy of the tape counter display and preventing the spool from undesirably unwinding (for example if the inhaler is accidentally dropped).

The support shaft may be forked and resilient so as to resiliently bias the support shaft and aperture into frictional engagement.

The support shaft may have two prongs, or in some cases more prongs, each prong having a radially extending protrusion having a friction edge extending therealong parallel to the longitudinal axis of the support shaft so as to frictionally engage the hole of the support shaft with a longitudinally extending friction interaction between the protrusion and the hole of the support shaft.

The hole may be a smooth cylindrical or substantially cylindrical hole.

Each of the above-mentioned inhalers according to various aspects of the present invention may have a medicament canister mounted thereon.

The canister may comprise a pressurized metered dose canister having a reciprocating rod extending from the canister and movable into its main canister portion to release a metered dose of medicament under pressure (e.g., by operating a metered dose valve within the canister body). The canister is operable by manually pressing on the main canister body.

In the case where one or more support rails or inner wall support structures are provided, the canister can always have a clearance of about 0.25 to 0.35 mm from the first inner wall support structure when it is inside the canister chamber. This clearance can be almost exactly 0.3 mm. This clearance, which can be applied to the canister body itself or the canister once the label has been applied, is sufficient to allow smooth movement of the canister in the inhaler while preventing significant oscillation of the canister, which could lead to inaccurate counting of the dose counter of the inhaler, particularly when the lower surface of the canister is arranged to engage an actuating member of the dose counter for counting purposes.

Another aspect of the invention provides a method of assembling a dose counter for an inhaler, the method comprising: providing a tape having dose indicia thereon; providing tape positioning indicia on the tape; and loading the tape while monitoring the tape positioning indicia with a sensor.

The method advantageously allows efficient and precise loading, for example by means of a wound tape.

The method may comprise providing the dose indicia as numbers.The method may comprise providing the tape positioning indicia as one or more lines across the tape.

The loading may include winding the tape onto a reel or shaft.

The method may include stopping winding when the positioning mark is in a predetermined position.

The method may include providing the tape with pixelated markings at locations along the tape spaced apart from the positioning markings.

The method may include providing a start point for the belt.

A further aspect of the invention provides a tape system for a dose counter for use with an inhaler, the tape system having a main elongate tape structure and dose indicia and tape positioning indicia located on the tape structure.

The belt positioning indicia may comprise at least one line extending across the belt structure.

The belt system may include pixelated markings located on the belt structure and spaced apart from the positioning markings.

The belt system may include an activation point located on the belt structure.

The positioning mark may be located between the timing point and the pixelated mark.

The main elongate strip structure may have at least one end thereof wound on a reel or shaft.

A further aspect of the invention provides a method of designing an incremental dose counter for an inhaler, the method comprising:

calculating a nominal canister release position and a dose counter position for a dose counter actuator for the inhaler; calculating a failure/success rate for the dose counter configured according to a tolerance level for counting each release of the inhaler, the dose counter actuator being applicable to the inhaler; and selecting the tolerance level so that the failure/success rate is at or below/above a predetermined value.

This is highly advantageous as it allows efficient and accurate prediction of the reliability of a series of inhaler counters manufactured according to the design.

The method may include selecting the failure/success rate to be no more than a one in 50 million failure rate.

The method may comprise setting a mean counting position so that a dose counter configured according to the tolerance is at or after its mean release position during a canister release movement.

The method may include setting the average count position to approximately 0.4 to 0.6 mm after the average release position, such as approximately 0.48 mm after the average release position.

The method may comprise setting a tolerance for the standard deviation of the release positions in a dose counter configured according to the tolerance to approximately 0.12 to 0.16 mm, such as approximately 0.141 mm.

The method may comprise setting a tolerance for the standard deviation of the counting positions in a dose counter configured according to the tolerance to approximately 0.07 to 0.09 mm, such as approximately 0.08 mm.

A further aspect of the invention comprises a computer implemented method of designing an incremental dose counter for an inhaler, the method comprising the method as set out in the last preceding aspect of the invention.The computer implemented method may comprise any of the optional features set out above.

A further aspect of the invention comprises a method of manufacturing a series of incremental dose counters for inhalers in a production run, the method comprising manufacturing the series of dose counters according to a design method as set out above in at least one of the preceding aspects of the invention.

Further aspects of the invention include a method of manufacturing a series of incremental dose counters for an inhaler, the method comprising manufacturing the dose counter having nominal canister release and dose counting positions of a dose counter actuator relative to a dose counter chassis (or inhaler body); and the method comprising constructing the dose counter with an average dose counting position in the series being at or after an average canister release position in the series during canister release.

The method may comprise configuring the dose counter such that the average dose count position in the series is approximately 0.4 to 0.6 mm, such as approximately 0.48 mm, after the average release position in the series.

The method may comprise configuring the dose counter such that the standard deviation of the release positions in the series is between approximately 0.12 and 0.16 mm, such as approximately 0.14 mm.

The method may comprise configuring the dose counter such that the standard deviation of the dose count positions in the series is between approximately 0.07 and 0.09 mm, such as approximately 0.08 mm.

Further aspects of the invention include a method of manufacturing a range of inhalers, the method comprising: performing a method as set out in at least one of the preceding aspects of the invention; and fitting each dose counter of the range of incremental dose counters to a respective body of the inhaler.

These aspects advantageously provide for a production run of a series of inhalers and dose counters that count reliably in operation.

Another aspect of the present invention provides an incremental dose counter for a metered dose inhaler having a body arranged to hold a canister for movement relative to the body, the incremental dose counter comprising: a main body; an actuator arranged to be driven in response to movement of the canister and to drive an incremental output member in a counting direction, the actuator being configured to restrict movement of the output member in a direction opposite to the counting direction. This advantageously enables the dose counter of the inhaler to maintain a reliable count of the remaining doses, even if it is dropped or otherwise jolted.

The output member may comprise a ratchet.

The actuator may comprise a pawl, and the ratchet wheel and pawl may be arranged to allow only one-way ratcheting movement of the wheel relative to the pawl.

The dose counter may comprise an anti-backward drive member fixed to the body.

When in the rest position of the dose counter, the ratchet may be capable of being in a configuration in which a rear surface of one tooth of the ratchet engages the anti-back drive member and the pawl is spaced from an adjacent rear surface of another tooth of the ratchet in the absence of positive driving/blocking engagement between the pawl and wheel.

In at least one of the aforementioned aspects of the present invention, the incremental counting system can be arranged to incrementally move the counter display device along a first direction from a first station to a second station in response to an actuation input, wherein an adjuster is provided, which is arranged to act on the counter display device at the first station to adjust the movement of the counter display device to incremental movement at the first station.

According to another aspect of the present invention, there is provided a dose counter for an inhaler, the dose counter having: a counter display device arranged to indicate dose information; a drive system arranged to incrementally move the counter display device from a first station to a second station in a first direction in response to an actuation input, wherein an adjuster is provided and arranged to act on the counter display device at the first station to adjust the movement of the counter display device to an incremental movement at the first station.

The adjuster is advantageous in that it helps prevent unwanted movement of the counter display in the event that the counter is dropped.

Preferably, the counter comprises a belt.

Preferably, the strip has dose counter indicia displayed thereon.The first station may comprise an area for holding a dose counter of the strip, the area being located before a display location, such as a display window, for the counter indicia.

The first station may include a first shaft on which the tape is arranged and from which it is unwound when the counter display device is moved.

The first shaft may be mounted for rotation relative to a substantially rotationally fixed element of the dose counter.

The adjuster may include at least one protrusion disposed on one of the first shaft and the substantially rotationally fixed element and incrementally engaging one or more structures on the other of the first shaft and the substantially rotationally fixed element.

At least two of the protrusions may be provided. Exactly two of the protrusions may be provided.

Each protrusion may include a rounded surface.

The at least one protrusion may be located on the substantially fixed element, which may comprise a fixed shaft fixed to the body of the dose counter, the first shaft being rotationally mounted to the fixed shaft.

Preferably, the fixed shaft has at least two elastically flexible legs (or forks). Each leg may have at least one protrusion formed on the leg in an outwardly facing direction, and the one or more structures are formed on the inwardly facing engagement surface of the first shaft, the at least one protrusion being arranged to elastically engage the one or more structures. Preferably, a series of structures are provided. An even number of structures may be provided. From 8 to 12 structures may be provided. In one embodiment, ten structures are provided.

Each of the structures may include a depression formed on the joint surface. Each depression may include a rounded surface wall portion, preferably merging into a flat wall portion surface on at least one side thereof. The joint surface may include a series of the depressions, and a convex wall portion of the joint surface may be formed between each adjacent two of the depressions, each convex wall portion including a convex rounded wall portion.

Each convexly rounded wall portion of each convex wall portion may be connected to each adjacent recess by said flat wall portion surface.

The fixed axle may include a split pin having a fork leg and each protrusion may be located on the fork leg.

The first shaft may comprise a substantially hollow spool.

The at least one structure may be located on an inner surface of the reel. In other embodiments, it may be located on an outer surface thereof. The engagement surface may extend partially along the reel, with the remainder or another portion of the respective inner or outer surface having a substantially smooth journal portion along at least a portion thereof.

The drive system may comprise a toothed ratchet arranged to act on a second shaft at the second station, the second shaft being rotatable to wind the belt onto the second shaft.

The second axis may be located on the body of the dose counter spaced apart from and parallel to the first axis.

The ratchet may be fixed to the second shaft and arranged to rotate with the second shaft.The ratchet may be fixed to an end of the second shaft and aligned coaxially with the second shaft.

The dose counter may comprise an anti-back drive system arranged to restrict movement of the second shaft.The anti-back drive system may comprise substantially fixed teeth arranged to act on teeth of the ratchet wheel.

According to a further aspect of the invention there is provided a shaft for retaining a counter strip in a dose counter for an inhaler, the shaft having an engagement surface comprising incrementally spaced formations around its circumference comprising a series of curved recesses and projections.

The shaft may comprise a hollow spool.

The engagement surface may be a substantially cylindrical inwardly directed surface.

The engaging surface may include a flat surface wall portion connecting each of the concave and convex wall portions.

Each recess may comprise a rounded wall portion.

Each raised wall portion may comprise a rounded wall portion.

The recesses may be regularly spaced about the longitudinal axis of the shaft.

The raised wall portions may be regularly spaced about the longitudinal axis of the shaft.

In some embodiments, there may be 8 to 12 of the concave and/or convex wall portions regularly spaced about its longitudinal axis.

One embodiment comprises ten of said concave and/or convex wall portions regularly spaced about the longitudinal axis of said shaft.

According to a further aspect of the invention, there is provided a shaft and counter belt assembly for a dose counter for use with an inhaler, the assembly comprising a rotatable shaft and a counter belt which is wound around the shaft and adapted to be unwound from the shaft upon actuation of the inhaler, the shaft having an engagement surface comprising incrementally spaced formations located around its circumference.

According to a further aspect of the present invention there is provided an inhaler for inhalation of medicaments and the like, the inhaler comprising a dose counter as in the second to last aforementioned aspect of the invention.

A preferred construction consists of a manually operated metered dose inhaler comprising a dose counter chamber including a dose display strip driven by a ratchet which in turn is driven by an actuating pawl actuated by movement of the canister, said strip being unwound from a storage reel during use of the inhaler, the rotation adjuster being provided for the storage reel and comprising a contoured engagement surface having a recess which engages a control element in the form of a protrusion on a resilient prong of a cotter pin, thereby allowing incremental unwinding of the storage reel but still preventing over-rotation in the event the inhaler is dropped on a hard surface.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention may be implemented in various ways and preferred embodiments of the dose counter, shaft, inhaler and assembly methods, design and manufacture will now be described with reference to the accompanying drawings, in which:

FIG1 is an isometric view of the body of a preferred embodiment of an inhaler according to the present invention, together with a mouthpiece cover therefor;

FIG2 is a top plan view of the components as shown in FIG1 ;

FIG3A is a cross-section on plane 3A-3A in FIG2 ;

FIG3B is a view corresponding to FIG3A , but with the dose counter assembled to the body of the inhaler;

FIG4A is an exploded view of the inhaler body, mouthpiece cover, dose counter, and dose counter window;

FIG4B is a view of the spring retainer of the dose counter taken along direction 4B in FIG4C ;

FIG4C is a top view of the spring retainer of FIG4B ;

FIG5 is a bottom view of the assembled inhaler body, mouthpiece cover, dose counter, and dose counter window;

6A, 6B, 6C, 6D, 6E, 6F, 6G and 6H are various views of the dose counter component of the inhaler;

7A and 7B are cross-sectional views showing the canister void within the body of the inhaler;

FIG7C is a further cross-sectional view similar to the cross-sectional view of FIG7B , but with the can removed;

FIG7D is a top plan view of the inhaler body;

8A , 8B, 8C and 8D show the inhaler body and dose counter components during assembly;

FIG9 shows a cross-sectional side view of a reference line of an actuating claw for a dose counter;

10A, 10B, 10C, 10D, 10E and 10F show various side views of the position and configuration of the actuating pawl, ratchet and counter pawl;

FIG11 shows the tolerance distribution of the start, reset, release, count and end positions of an actuator of a dose counter;

FIG12 is an enlarged view of a portion of FIG4A;

Figure 13 shows an end portion of the tape of a dose counter;

FIG14 shows a computer system used to design a dose counter;

FIG15 is an isometric view of a modified storage reel for use with the inhaler of FIGS. 1 to 14 ;

FIG16 shows an end view of the storage reel of FIG15;

Fig. 17 is a section through the longitudinal axis of the storage reel of Figs. 15 and 16;

18A to 18C are views of the storage spool of FIGS. 15 to 17 mounted in the dose counter chassis of FIGS. 1 to 14 , with the control element of the fork of the second shaft (or cotter pin) having a slightly different profile than that of FIG. 6F , the fork being in a compressed configuration;

19A to 19C are views equivalent to those of FIGs. 18A to 18C , but with the fork in a more extended configuration due to a different rotational position of the storage spool;

FIG20 is an isometric view of the chassis assembled and including the storage reel of FIG15 to 17 but without the belt for clarity;

FIG21 is a view of a preferred embodiment of a dry powder inhaler according to the present invention;

FIG22 is an exploded view of the inhaler of FIG21;

FIG23 is a view of the dose counter of the inhaler of FIG21;

FIG24 is an exploded view of the dose counter shown in FIG23;

FIG25 is an exploded view of the various parts of the inhaler of FIG21; and

FIG. 26 is a view of the yoke of the inhaler of FIG. 21 .

DETAILED DESCRIPTION

Figure 1 shows a body 10 of a manually operated metered dose inhaler 12 according to a preferred embodiment of the present invention and having a nozzle cover 14 securable over a nozzle 16 of the body.

The main body has a tank chamber 18 into which a tank 20 (Fig. 7A) can slide. The tank 20 has a substantially cylindrical main sidewall 24 connected to a head portion 28 by a tapered section 26, the head portion having a substantially flat lower surface 30 having an outer annular drive surface 32 arranged to engage and drive an actuating pin 34 of a dose counter 36, as will be described. Centrally and axially extending from the lower surface 30 is a valve stem 38 arranged to sealably engage in a valve stem seat 40 of the main body 10 of the inhaler 12. The valve stem seat 40 has a passage 42 leading to a nozzle 44, which is used to direct the contents of the tank 20, i.e., the active drug and propellant, to an air outlet 46 of the inhaler body 12. It will be appreciated that, due to the gap 48 between the canister 20 and the inner wall 50 of the body 10 of the inhaler 12, the open top 52 of the body 10 forms an air inlet into the inhaler 12, which air inlet communicates with the air outlet 46 via an air passage 54, such that the contents of the canister exiting the nozzle 44 mix with air inhaled by the user through the air passage 54 so as to pass together through the air outlet and into the user's mouth (not shown).

The dose counter 36 will now be described. The dose counter 36 includes an actuator pin 34 that, once installed in the body 10, is biased upward from below by a return spring 56. As best shown in Figures 4A, 6H, and 8A, the pin 34 has side surfaces 58, 60 arranged to slide between corresponding guide surfaces 62, 64 located in a dose counting chamber 66 of the body 10, and an end stop surface 68 arranged to engage a corresponding end stop 70 formed in the dose counting chamber 66 to limit the upward movement of the pin 34. The pin 34 has a top portion 72 that is cylindrical and extends through an aperture 74 formed through a partition wall 76 that separates the dose counting chamber 66 from the canister chamber 18. The top portion 72 of the pin 34 has a flat top surface 78 that is arranged to engage the outer annular drive surface 32 of the canister 20.

The actuation pin 34 is integrally formed with a drive or actuation pawl 80. The actuation pawl 80 has a generally inverted U-shaped configuration having two mutually spaced and parallel arms 82, 84 extending from the base of the actuation pin 34, each arm retaining at its respective distal end 88 an opposite end of a pawl member 90 extending in a direction generally perpendicular to the arms 82, 84 to provide what may be referred to as a "saddle" drive arrangement for pulling each of the eleven drive teeth 92 of a ratchet wheel 94 of an incremental drive system 96 or ratchet mechanism 96 of the dose counter 36. As shown, for example, in FIG10B , the pawl member 90 has a sharp lower longitudinal side edge 98 arranged to engage the drive teeth 92, the edge-to-surface contact provided by such engagement providing very precise positioning of the actuation pawl 80 and, consequently, rotational positioning of the ratchet wheel 94.

The dose counter 36 also has a chassis preassembly 100, as shown in Figures 4A and 6A, which includes a chassis 102 having: a first shaft 104 that receives the ratchet 94 fixed to the reel shaft 106; and a second shaft (or cotter pin) 108 that is parallel to the first shaft 104 and spaced apart from the first shaft 104, and which receives the tape storage reel 110 in a slidable and rotatable manner.

6B , when the inhaler has not been used at all, the majority of the tape 112 is wound around the tape storage spool 110, and the tape 112 has a series of regularly spaced numbers 114 displayed along it to indicate the number of doses remaining in the canister 20. As the inhaler is used repeatedly, as the actuating pin 34 is operated by the canister 20, the ratchet 94 is rotated by the actuating pawl 80, and the tape 112 is incrementally and gradually wound from the second shaft 108 onto the reel shaft 106. The tape 112 passes around a tape guide 116 of the chassis 102, allowing the numbers 114 to be displayed through a window 118 in a dose counter chamber cover 120, the tape having dose markings 122 formed thereon or otherwise located thereon.

As shown in Fig. 6 A and 6D, second shaft 108 is formed with two forks 124,126.Fork 124,126 deviate from each other.These forks have the position relative along diameter direction on second shaft 108, the friction or control element 128,130 that is positioned thereon, each fork described friction or control element.Each control element longitudinally extends along its fork 124,126 separately and has longitudinally extending friction surface 132,134, this friction surface extends substantially parallel to the longitudinal axis of second shaft and is suitable for being engaged in the substantially cylindrical hole 136 in the tape storage reel 110.This control arrangement that is arranged between hole 136 and control element 128,130 provides good rotation control for tape storage reel 110, makes it can not unwind (such as when inhaler falls) unexpectedly.Unwinding tape storage reel 10 and overcoming the required belt force of this friction force are about 0.1N.

As can be seen in Figures 6D, 6G and 10A to 10F, the chassis 102 is provided with an anti-return drive tooth 138 or counting pawl 138 that is resiliently and substantially fixedly mounted thereto. As will be described below and as can be seen in Figures 10A to 10F, when the actuating pin 34 is fully depressed to release a metering valve (not shown) within the canister 20, the actuating pawl 80 pulls down one of the teeth 92 of the ratchet wheel 94 and rotates the wheel 94 counterclockwise as shown in Figure 6D so that one tooth 92 clears the counting pawl 138, thereby incrementally winding the tape 112 a distance relative to the dose indicia 122 on the dose counter chamber 120 to indicate that a dose has been used.

10B , the teeth of ratchet wheel 94 have tips 143 that are rounded with a 0.1 mm radius between flat surfaces 140, 142. Ratchet wheel 94 has a central axis 145 that is 0.11 mm above reference plane 220 ( FIG. 9 ). The top/nose surface 147 of the anti-backward drive tooth 138 is located 0.36 mm above reference plane 220. The vertical (i.e., transverse to reference plane 220 - FIG. 9 ) distance between the top nose surface 147 of the anti-backward drive tooth and the central axis 145 of wheel 94 is 0.25 mm. The projection surface 144 has a lateral extension of 0.20 mm, a flat portion 145' having a vertical length of 1 mm, a width of the projection surface of 1.22 mm (along axis 145), a top 149 of the projection surface 144 vertically below axis 145 of 3.02 mm, and a flat portion 145' spaced 2.48 mm laterally from axis 145 (i.e., parallel to reference plane 220). When the actuator pawl 80 and pin 34 are in the starting configuration, the top surface 78 of the pin 34 ( FIG. 6H ) is 11.20 mm above the reference plane 220 ( FIG. 9 ). The valve stem 22 is 11.39 mm long, and when the canister is at rest awaiting actuation, the drive surface 32 of the canister 20 is 11.39 mm above the reference plane 220, resulting in a clearance of 0.19 mm between the canister 20 and the pin 34 in this configuration.

10A and 10B show the actuating pawl 80, ratchet 94 and counter pawl 138 in a starting position, wherein the flat top 78 of the pin 34 has not yet engaged the outer annular drive surface 32 of the canister 20, or at least has not yet been pushed down during canister depression.

In this "start" position, the counting pawl 138 engages the check rear surface 140 of one of the teeth 92 of the ratchet wheel 94. The underside edge 98 of the actuating pawl is a distance "D" (FIG. 9) of 1.33 mm above a reference plane 220 that passes through the bottom surface or shoulder 41 of the valve stem seat 40, the reference plane 220 being perpendicular to the main axis "X" of the body 10 of the inhaler 12, which is coaxial with the center of the valve stem seat aperture 43 and parallel to the direction in which the canister 20 slides in the body 10 of the inhaler 12 when the canister is released.

As shown in Figure 10B, the advantageous feature of said construction is that, when the inhaler 12 is not used for inhalation, the pawl teeth/actuator 90 serves as a supplementary anti-return drive member. In particular, if the inhaler 12 is accidentally dropped, causing the dose counter 36 to vibrate, then, if the wheel 94 will attempt to rotate clockwise (backward) as shown in Figure 10B, the rear surface 140 of the tooth will engage the tooth member 90 of the pawl 80 and be blocked by the tooth member. Therefore, even if the anti-return drive tooth 138 is temporarily bent or overcome by this vibration, the undesirable backward rotation of the wheel 94 is prevented, and when the next tank release sequence is released, the pawl 90 will force the wheel 94 to catch up with its correct position so that the dose counter 36 continues to provide correct dose indication.

FIG10C shows a configuration in which the actuator pawl 80 has been depressed by the canister 20 via the pin 34 to a position where the side edge 98 of the pawl member 90 is engaged with one of the teeth 92, and thus any further depression of the pin 34 will begin to rotate the wheel 94. This is referred to as the "reset" position or configuration. In this configuration, the lower side edge 98 of the actuator 80 is 0.64 mm above the reference plane 220.

FIG10D shows a configuration in which the actuator pawl 80 has been moved to a position lower than that shown in FIG10C and in which the metered dose valve (not shown) within the canister has been released in this precise position to discharge the active drug and propellant through the nozzle 44. It will be noted that in this configuration, the counter pawl 138 is very slightly spaced from the rear surface 140 of the tooth 92 that it had engaged in the configuration of FIG10D. The configuration shown in FIG10D is referred to as a "release" configuration. In this configuration, the lower edge 98 of the actuator 80 is 0.47 mm below the reference plane 220.

FIG10E illustrates another step in this sequence, referred to as the "count" position, in which the actuating pawl 80 has rotated the ratchet wheel 94 over the circumferential angular distance between two of the teeth 92, such that the counting pawl 138 has just completed its advance along the forward surface 142 of one of the teeth 92 and has resiliently cleared that tooth to engage the rear surface 140 of the next tooth. Thus, in this "count" configuration, sufficient travel of the pin 34 has occurred such that the band 112 of the dose counter 36 will count down exactly one dose. In this configuration, the lower edge 98 of the actuator is 0.95 mm below the reference plane 220. Thus, in this position, the actuator 80 (including the edge 98) is typically 0.48 mm lower than in the released configuration. It has been found that, although the counting configuration occurs further than the released configuration, counting is highly reliable, with a failure rate of less than one in 500 million. This is due, at least in part, to momentum effects and, in some embodiments, to the release of the internal metering valve of the canister upon release of some back pressure on the user.

In the configuration of FIG10F , the pawl 80 has been further depressed by the canister 20 via the pin 34 to a position where it has just disengaged from one of the teeth 92, and the actuating pawl 80 assists in this disengagement by engaging one of the arms 84 with a projection surface 144 on the chassis 102 (see FIG6G ). At this disengagement point (referred to as the “end” configuration), it will be seen that the counting pawl 138 is positioned exactly halfway, or substantially halfway, between two of the drive teeth 92. This advantageously means that there is minimal potential for any double counting or non-counting, which would be undesirable. In this end configuration, the side edge 98 of the actuator is 1.65 mm below the reference plane 220. It will be appreciated that any further depression of the actuating pawl 80 and pin 34 past the “end” configuration shown in FIG10F will not affect the position of the band 112 displayed by the dose counter 36, as the actuating pawl 80 is disengaged from the ratchet 94 when it is below the position shown in FIG10F .

As shown in Figures 7C and 7D , the inner wall 50 of the body 10 is provided with a two-step support rail 144 that extends longitudinally within the body and is positioned proximate to the aperture 74. As shown in Figure 7B , two diametrically opposed support rails 146 are also provided, and this diametric opposition means that a vertical plane (not shown) can pass substantially directly through the first rail 144, the aperture 74, the central aperture 148 of the valve stem holder 40 (in which the pot stem 25 is located), and the second two-step support rail 146. As shown in Figure 7A and schematically illustrated in Figure 7B , the rails 144, 146 provide a maximum radial clearance of almost exactly 0.3 mm between the pot 20 and the rails 144, 146, with a typical range of approximately 0.25 to 0.35 mm. This clearance in this plane means that the pot 20 can only swing forward and backward in this plane, away from the actuator pin 34. The relatively small distance and the above thus prevent the canister from rocking and changing the height of the actuating pin 34, thereby undesirably changing the accuracy of the dose counter 36. This is therefore highly advantageous.

The inner wall 50 of the body 10 is provided with two pairs of rails 152, 154 extending inwardly from the inner wall 50 by different constant radial amounts and two further two-step rails 150, so that for all rails 144, 146, 150, 152, 154 spaced about the circumference of the inner wall 50, a maximum clearance of almost exactly 0.3 mm is achieved substantially around the canister 20 to prevent undue wobbling while still allowing the canister to move freely within the inhaler 12. As will be best seen in FIG7C , for example, the two-step rail has: a first portion near the outlet end 156 of the canister chamber 18 having a substantially constant radial or inwardly extending width; a first step 160 leading to a second portion 162 of the rail; a second portion 102 having a lesser radial or inwardly extending extent than the first portion 156; and a final second step 164 where the rail merges into the main inner wall 50 major surface.

A method of assembling the inhaler 12 will now be described.

Referring to Figure 8A, the body 10 of the inhaler 12 is formed from two or more plastic mouldings that have been joined together in the configuration shown.

As shown in FIG. 8B , the actuation pawl 80 and pin 34 translate forward into a position into the pin receiving area 166 in the dose counter chamber 66 , and the pin 34 and actuator 80 may then be raised until the pin 34 emerges through the aperture 74 .

Next, the return spring 56 can be inserted under the pin 34, and the substantially cylindrical annular lower end 168 of the spring 56 can be moved into engagement with the shelf 170 of the spring retainer 172 in the dose counter chamber 66 by pliers or a pliers-like assembly tool (not shown). The spring retainer 172 is U-shaped, and the shelf 170 is U-shaped and has a groove 174 formed thereunder. As shown in Figures 4B, 4C, and 12, the shelf 170 includes three chamfered surfaces 176, 178, 180 that are arranged to facilitate moving the lower end 168 of the spring into position on the shelf using an assembly tool (not shown). Once the lower end 168 of the spring is in place, the assembly tool (not shown) can be easily removed at least partially through the groove 174 below the lower end 168 of the spring 56.

The tape 112 is attached at one end (not shown) to a tape storage spool 110 and is wound onto the spool by a motor 200 ( FIG. 13 ) having a hexagonal output shaft 202 that engages in a hexagonal slot 204 ( FIG. 6B ) in the spool. During winding, the tape is monitored by a sensor 206, which may be in the form of a camera or laser scanner, which feeds data to a computer controller 205 for the motor 200. The controller 205 identifies three positioning marks 210 in the form of lines across the tape 112 and stops the motor 202 when the tape 112 is almost completely wound onto the spool 110, so that the distal end 212 of the tape 112 can be secured to the reel shaft 106, for example, by adhesive. The controller 205 also recognizes the pixelated tape size markings 214 observed by the sensor 206 and records the details of the tape 112 (such as the number of numbers 114 on the tape, such as one hundred and twenty or two hundred) in the storage system data memory 217. Next, the tape reel is wound until the appropriate position of the line 210, in which the start point 216 will be in a position to be located in the window 118 when the inhaler 12 is fully assembled once the reel 110 and reel shaft 106 are slid onto the second shaft 108 and the first shaft 104. In this embodiment, the reel 110 and reel shaft 106 can be slid onto the shafts 108, 104 before the tape 112 is secured to the reel shaft 106, and the reel shaft can then be wound to the position of the start point 216.

Next, the assembled dose counter components of the chassis preassembly 100 shown in FIG6B can be inserted into the dose counter chamber 66 as shown in FIG8C , with the pins 182, 184, 186 formed on the body 10 in the dose counter chamber 66 extending through (or at least into) the holes or slots 188, 190, 192 formed on the chassis 102. The pins 182, 184, 186 are then heat-set by the chassis 102 being relatively firmly pushed toward the body 10, and the chassis 102 is thereby very firmly held in position in the body and cannot move, thereby helping to provide great accuracy for the dose counter 36. Next, as shown in FIG8D , the dose counter chamber cover 120 can be assembled over the dose counter chamber 66 and fixed in place, such as by welding, with the activation point 216 visible through a window.

When preparing the inhaler 12 for first use, the user can prime the inhaler by depressing the canister 20 three times, which will cause the first number 114 on the tape to be displayed through the window 118 at the location of the activation point 216. The number 114 shown in FIG. 8D is "200," thereby indicating that 200 doses remain to be dispensed from the canister 20 and inhaler 12.

8D and as shown in FIG5 , an open drain hole 194 is provided in the bottom of the dose counter chamber 66 by a substantially semicircular cutout or recessed structure 196 in the lower surface 198 of the inhaler's body 10. Thus, if a user (not shown) were to decide to wash the inhaler's body 10 (e.g., after encountering an unsanitary situation or simply as an option), the drain hole 194 allows water to initially drain from within the dose counter chamber 66 and thereafter also evaporates the water or any aqueous matter in the dose counter chamber 66 so that the window 118 does not undesirably fog up.

Figure 14 shows computer system 230, this computer system is used for design dose counter 36, and be used for calculating distribution especially, this distribution represents actuator downside edge 98 with respect to the beginning of reference plane 220 (Fig. 9), reset, release, mean position and the standard deviation in the product series of the inhaler of counting and end position, and therefore represents actuating pawl 80 substantially with respect to the beginning of the main body 10 of ratchet 94, chassis 102 and (when inhaler 12 are assembled fully) inhaler 12, reset, release, mean position and the standard deviation in the product series of the inhaler of counting and end position.Computer system 230 comprises data storer 232, CPU 234, input device 236 (such as keyboard or communication port) and output device 238 (such as communication port, display screen and/or printer). The user can input data by input device 236, when various dose counters will be configured to a series of dose counter position sets, these data can be used for predicting counting failure rate by CPU 234 in mathematical calculation, this position set has given average and standard deviation, and considers that any momentum/inertia effect and metering valve user back pressure reduce effect (this will occur when the jar of given type is discharged).Therefore, computer system 230 is used for designing this distribution mathematically.For inhaler 12 described here with dose counter 36 and jar 20, this distribution is designed to as shown in Figure 11.The x-axis illustrates the distance of the downside surface 98 of the actuator 80 above the reference plane 220, and the y-axis represents distribution. Thus, curve 240 shows the starting configuration having an average value of 1.33 mm (standard deviation of 0.1 mm) above the reference plane 200, curve 242 shows the reset configuration having an average value of 0.64 mm (standard deviation of 0.082 mm) above the reference plane 220, curve 244 shows the release configuration having an average value of 0.47 mm (standard deviation of 0.141 mm) below the reference plane 220, curve 246 shows the counting configuration having an average value of 0.95 mm (standard deviation of 0.080 mm) below the reference plane 220, and curve 248 shows the ending configuration having an average value of 1.65 mm (standard deviation of 0.144 mm) below the reference plane 220.

Figures 15 to 20 show a preferred embodiment according to the present invention, which is an improved version of the embodiment described with reference to Figures 1 to 14. In these figures, identical reference numerals have been used for those in the preceding figures to indicate equivalent parts. Except for the following modification, inhaler 12 is identical to the inhaler in Figures 1 to 14.

Firstly, it can be seen that a modification is present in that the drive teeth 92 of the ratchet wheel 94 have a different profile to that of the drive teeth in Figures 1 to 14. In this embodiment, there are only nine ratchet teeth 94 instead of eleven.

18C and 19C , the control elements 128, 130 on the forks 124, 126 of the second shaft 108 have a tapered profile that differs from the profile of the control elements 128, 130 shown in FIG 6F . However, either profile may be used with the embodiments of FIG 15 to 20 .

Furthermore, as shown in FIG15 , the tape storage reel 110 has an inwardly facing, substantially cylindrical engagement surface 300 having an undulating shape extending partially along the engagement surface. The engagement surface 300 has a cross-section 301 perpendicular to the longitudinal length of the constant storage reel 110. This cross-section 301 can be seen in FIG16 and consists of a series of ten regularly spaced depressions 302 and ten convex wall portions 304. The convex wall portions 304 are equally spaced between the depressions 302. Each depression 302 has a radius of 0.2 mm. Each convex wall portion 304 also has a radius of 0.2 mm. Finally, the cross-section 301 includes flat wall portions 306 between all the rounded wall portions of the depressions 302 and convex wall portions 304. The geometry of the cross-section 301 is therefore defined by the radii of the depressions 302 and convex wall portions 304, the flat wall portions 306, and the presence of ten depressions 302 and convex wall portions 304.

The minor diameter of the engagement surface 300 (i.e., between the ends of the opposing convex wall portions 304) is 2.46 mm. The major diameter of the engagement surface 300 (i.e., between the outermost portions of the recess 302) is 2.70 mm. The undeformed end-to-end maximum diameter of the prongs 124, 126 of the cotter pin (second shaft) 108 (i.e., in the region of maximum radial extension of the control elements 128, 130) is 3.1 mm, and it will be understood that, in all rotational configurations of the storage reel 110 relative to the cotter pin 108, once the storage reel 110 has been assembled onto the cotter pin 108, the prongs 124, 126 are elastically compressed. When the cotter pin 108 is in the undeformed, pre-insertion state, the minimum gap between the prongs 124, 126 in the plane of the cross-sections of Figures 18C and 19C is 1 mm. When the cotter pin 108 is at maximum compression, as shown in Figures 18A to 18C , when the control elements 128, 130 are shown engaged on top of the raised wall portion 304, the gap 308 between the tips 310, 312 of the prongs 124, 126 is 0.36 mm. On the other hand, as shown in Figures 19A to 19C , when the cotter pin 108 is at minimum compression (once inserted into the storage reel), when the control elements 128, 130 rest in the recess 302, the gap 308 between the tips 310, 312 of the prongs 124, 126 is 0.6 mm. The control elements 128, 130 radiate outwardly with a radius also of 0.2 mm so that they can rest squarely on the recess 302 with full surface contact (at least at the axial location on the cotter pin where the tapered control elements are at their greatest radial extent) without rattling into the recess 302, locking onto the recess 302, or failing to fit within the recess 302. Therefore, the radius of the control elements 128, 130 is preferably substantially the same as the radius of the recess 302.

It will be understood that while Figures 18B and 19B are end views along the coaxial axis of the storage spool 110 and the cotter pin 108, Figures 18A and 19A are cross-sections. Figure 19A is a cross-section on plane A-A' in Figure 19C, while Figure 18A is a cross-section at the same plane, but of course with the storage spool 110 rotated relative to the cotter pin 108.

When the inhaler 12 is used and the ratchet 94 is rotated to count the used doses, the storage reel is rotated incrementally through a rotational position that resists rotation (i.e., due to the increased compression of the cotter pin 108 in this rotational position) and a rotational position that facilitates rotation (i.e., due to the reduced compression of the cotter pin 108 in this rotational position), and this may involve the storage reel 110 clicking forward to a next position equivalent to the position in Figures 19A to 19C, in which the control elements 128, 130 of the cotter pin are located in the recess 302. This functionality firstly allows the storage reel to be unwound as needed during use, but also prevents the tape 112 from becoming unwound during transport (if the inhaler 12 is dropped onto a hard surface, for example). This is very advantageous because the tape 112 is prevented from moving to a position where it would give an incorrect reading of the number of doses in the canister.

During the compression and expansion of fork radially between two structures shown in Figure 18 C and the 19C, fork 124,126 rotates around the point 316 on the cotter pin, and fork 124,126 meets at this point.This rotational action means that there is cam action and there is not significant friction between fork 124,126 and engagement surface 300, but, though like this, the elastic force that provides by the regulator that is formed by engagement surface 300 and fork 124,126 can regulate the unwinding of band, make during transportation or when inhaler 12 falls, the unwinding of band is not easy to take place.Have found during test that 0.3 to 0.4N power need be applied to band 112 to overcome the regulator at storage reel 110 places.0.32N is realized by the control element 128 with the profile shown in Figure 19 C, and 0.38N is realized by being changed into the profile of the control element 128 that is shown and described as reference figure 6 F. These forces are significantly greater than the 0.1 N force described above and substantially prevent unwanted movement of the strap, even if the inhaler is dropped onto a hard surface. The improved arrangement of Figures 15 to 20 does not "constantly" provide such forces, so that there is generally no undesirably high friction of the strap 112 as it passes over other components of the dose counter, because, due to the incremental nature of the spring force at the adjuster, the strap 112 can be incrementally relaxed as it slides over stationary chassis components.

Instead of having ten recessed and convex wall portions 302 and 304, other numbers could be used, such as 8 or 12. However, it is preferred to have an even number (particularly due to the provision of two control elements 128, 130) so that all control elements 128, 130 will expand and contract simultaneously. However, other arrangements with three or more prongs are contemplated, and the number of recessed and convex wall portions can be maintained at an integer divisible by the number of prongs to maintain a system with simultaneous expansion and contraction. For example, it is contemplated to use 9, 12, or 15 recessed and convex wall portions with three prongs.

Instead of having the engagement surface 300 on the inside of the storage reel 110, the engagement surface may be placed on the outside of the storage reel 110 to be engaged by flexible external legs/pawls or the like.

It will be noted that the adjustment provided by the engagement surface 300 and the forks 124, 126 does not allow rotation of the storage spool in only one direction (as is the case with the ratchet 94). Rotation in both directions (i.e., forward and backward) is possible. This means that during assembly, if desired, the storage spool 110 can be wound backward during or after the spool 100, shaft 106, and belt 112 are assembled onto the carriage 102.

The storage reel 110 and the carriage 102 including the cotter pin 108 are molded from a polypropylene material.

16 , the cross-sectional shape 301 is not symmetrical within the hexagonal socket 204. This has enabled the hexagonal socket 204 to be maintained at a useful size while still allowing the desired size and geometry of the cross section 301 to mate without interference with the hexagonal shape of the hexagonal socket 204, and also allowing molding to occur during manufacturing.

As shown in Figure 17, the storage reel 110 has a series of four circumferential ribs 330 spaced apart along the interior of the storage reel. During molding, these ribs hold the storage reel 110 on the correct side of the molding tool.

Figure 21 and 22 shows and is used for dispensing dry powdered medicament with metered dose so that the inhaler 510 that patient sucks according to preferred embodiment of the present invention.Inhaler 510 is disclosed among Fig. 1 to 16 of EP-A-1330280, and the content of EP-A-1330280 is incorporated into here fully by reference at this, but the storage reel 110 and the second shaft 108 of dose counter 516 are modified so that as in Figure 15 to 20.Therefore, dry powder inhaler 510 comprises shell 518 and the assembly 512 (seeing Figure 21) that is contained in this shell usually.Shell 518 comprises: housing 520, and this housing has open end 522 and nozzle 524 (Figure 25) so that patient sucks; Lid 526, this lid is fixed to and the open end 522 of closed housing 520; And cover 528, this cover is mounted to housing 520 in a pivotable manner so that cover nozzle 524. As shown in FIG22 , the inhaler 510 further includes an actuating spring 569, a first yoke 566 having an opening 572, a bellows 540 having a crown 574, a reservoir 514, a second yoke 568 to which the reservoir 542 and the dose counter 516 are mounted, and a housing 520 having a transparent window 5130 thereon for viewing the dose counter band indicia 5128. The dose metering system further includes two cams 570 mounted on the nozzle cover 528 and movable with the cover 528 between open and closed positions. Each cam 570 includes an opening 580 for allowing an outwardly extending hinge 582 of the housing 520 to pass therethrough and be received in a first recess 584 of the cover 528. The cam 570 also includes a boss 586 that extends outwardly and is received in a second recess 588 of the cover 528, so that the cover 528 pivots about the hinge 582 and the cam 570 moves with the cover 528 about the hinge 582. As described in EP-A-1330280, the cam 570 acts on the cam follower 578 to move the second yoke 568 up and down and thereby operate the dose counter by engaging the pawl 5138 with the tooth 5136 on the second yoke 568. The remaining components of the inhaler are arranged as in EP-A-1330280 and operate as described in EP-A-1330280.

The dose counter system 516 thus includes a strip or tape 5128 (FIGS. 23 and 24) having sequential numbers or other suitable indicia printed thereon that is aligned with a transparent window 5130 disposed in the housing 18 (see FIG. 22). The dose counter system 516 includes: a rotatable storage reel 110 (as described above); an indexing spool 5134 rotatable in a single direction; and a strip 5128 wound up and received on the reel 110 with a first end 5127 secured to the spool 5134, wherein the strip 5128 is unwound from the reel 110 such that the indicia is sequentially displayed as the spool 5134 rotates or advances. In FIGs. 23 and 24, the undulating engagement surface 300 of the reel 110 is not shown for clarity.

The bobbin 134 is arranged to rotate when the yoke 566, 568 moves, to realize delivering a dose of medicament from the reservoir 514, so that the numeral on the strip 5128 advances to indicate that another dose has been dispensed by the inhaler 510. The strip 5128 can be arranged so that the numeral or other suitable marking increases or decreases when the bobbin 5134 rotates. For example, the strip 5128 can be arranged so that the numeral or other suitable marking reduces the quantity of the dosage remaining in the indication inhaler 510 when the bobbin 5134 rotates. Alternatively, the strip 5128 can be arranged so that the numeral or other suitable marking increases to indicate the quantity of the dosage dispensed by the inhaler 10 when the bobbin 5134 rotates.

The indexing shaft 5134 includes radially extending teeth 5136 that, when the yoke is moved, engage with pawls 5138 extending from the cam follower 578 of the second yoke 568 to rotate or advance the indexing shaft 5134. More particularly, the pawls 5138 are shaped and arranged so that they engage the teeth 5136 and advance the indexing shaft 5134 only when the nozzle cover 528 is closed and the yokes 566, 568 are retracted toward the lid 526 of the housing 518.

The dose counter system 516 also includes a chassis 5140 that secures the dose counter system to the hopper 542 and includes a shaft 108, 5144 for receiving the spool 110 and the indexing spool 5134. As described above with reference to Figures 15 to 20, the spool 108 is forked and includes radially projecting tabs 5146 that create a resilient resistance to rotation of the spool 110 on the shaft 108 by engaging with the contoured engagement surface 300 within the spool 110. A clutch spring 5148 is received on the end of the indexing spool 5134 and is locked to the chassis 5140 to allow the spool 5134 to rotate in only a single direction.

Various modifications may be made to the embodiments shown and described above without departing from the scope of the invention as defined by the appended claims interpreted in accordance with the patent statutes.

Claims (11)

1. A method for assembling a dose counter for an inhaler, the method comprising: A tape is provided, on which dosage markings are provided; Provide separate size markings; The strip is provided with positioning marks; Attach one end of the strip to the storage reel; Load the tape onto the storage reel; Secure the distal end of the belt to the belt reel shaft; The tape is wound onto the tape reel shaft, and the tape positioning marks and tape size marks are monitored by sensors; and The storage reel and the tape reel are mounted on the dose counter. 2. The method of claim 1, wherein the method includes providing the dose marker as a number. 3. The method of claim 1 or claim 2, wherein the method includes providing the band positioning mark as one or more lines across the band. 4. The method of claim 1, wherein the method includes stopping winding when the positioning mark is in a predetermined position. 5. The method of claim 1 or 2, wherein the band size mark includes a pixelated mark located at a position along the band spaced apart from the band positioning mark. 6. The method of claim 1 or 2, wherein the method includes providing a start point for the band. 7. A belt system for a dose counter used in an inhaler, the belt system having a main elongated belt structure and dose markings, separate belt size markings and belt positioning markings located on the belt structure, wherein a first end of the belt structure is attached to a storage reel, and a second end of the belt structure is fixed to a belt reel shaft, and wherein, prior to complete assembly of the inhaler, the belt structure is wound around both the storage reel and the belt reel shaft. 8. The belt system of claim 7, wherein the belt positioning mark comprises at least one line extending across the belt structure. 9. The belt system as claimed in claim 7 or claim 8, wherein the belt size marking includes pixelated markings located on the belt structure and spaced apart from the belt positioning markings. 10. The belt system as claimed in claim 7 or claim 8, wherein the belt system includes a starting point located on the belt structure. 11. The belt system of claim 7 or claim 8, wherein the belt size markings include pixelated markings located on the belt structure and spaced apart from the belt positioning markings, the belt system including a starting point located on the belt structure, and the belt positioning markings located between the starting point and the pixelated markings.