Device for dispensing a plurality of unitary doses of dry powder, and inhaler comprising such device

Device for dispensing a plurality of unitary doses (2) of dry powder, includes at least one support comprising conduits each defining a flow path for an airstream carrying one of the unitary dose (2), the support having first (26) and second (27) members secured to one another so that a first conduit portion (29) of the first member faces a second conduit portions (43) of the second member to define one of the conduits, and a first separation portion (30) of the first member faces a second separation portions (45) of the second member, the support comprising a plurality of barrier-forming elements (31, 46) each arranged between corresponding first (30) and second (45) separation portions to prevent dry powder from passing from one of the conduits to one of the adjacent conduits.

The invention relates to a device for dispensing a plurality of unitary doses of dry powder, and to an inhaler comprising such device.

In particular, the invention relates to a device for dispensing a plurality of unitary doses of dry powder, comprising at least one support for a carrier having a plurality of housings for respective unitary doses, the support comprising a plurality of conduits adapted to be connected respectively to the housings, each conduit defining a flow path for an airstream carrying the unitary dose through inhalation by a user, wherein the support has:a first member having a plurality of first conduit portions adjacent to each other, and a plurality of first separation portions each arranged between two adjacent first conduit portions, anda second member having a plurality of second conduit portions adjacent to each other, and a plurality of second separation portions each arranged between two adjacent second conduit portions,

the first and second members being secured to one another so that each first conduit portion faces one corresponding of the second conduit portions to define one of the conduits, and each first separation portion faces one corresponding of the second separation portions.

Such a device is known from WO-A-2005/002654.

The device disclosed in the aforementioned document provides for one sole conduit for each unitary dose of dry powder. In use, a user actuates the device to inhale a unitary dose of medicine in the form of dry powder through one of the conduits. Upon a subsequent actuation of the device, a new unitary dose can be inhaled through a new conduit.

With the known device, it may happen, under some conditions of misuse, that an excess of powder is inhaled by the user. It is especially the case when the device is activated so that a new unitary dose is ready to be inhaled after the device has already been activated without the previous unitary dose being inhaled.

Actually, it has been found that powder of a previous unitary dose that has not been inhaled may be drawn in the airstream of the subsequent unitary dose, resulting in a so called cross-dosing.

The invention aims to solve the above mentioned problem.

To this end, according to a first aspect, the invention provides for a device of the aforementioned type wherein the support comprises a plurality of barrier-forming elements each arranged between corresponding first and second separation portions to prevent dry powder from passing from one of the conduits to one of the adjacent conduits.

Therefore, the barrier-forming elements of the invention prevent dry powder passing between the corresponding first and second separation portions of the first and second members, and thereby minimise cross-dosing and the risk of inhalation of an excess of powder, especially when the previous unitary dose has not been inhaled.

In particular, at least one of the barrier-forming elements may comprise a baffle between the corresponding first and second separation portions.

As a complementary feature or an alternative feature, at least one of the barrier-forming elements may comprise at least one rib and at least one groove adapted to receive said rib, one of said rib and said groove being arranged on the first separation portion and the other of said rib and said groove being arranged on the corresponding second separation portion. In particular, the rib may include a first pair of opposed surfaces inclined with respect to one another, and the groove may include a second pair of opposed surfaces inclined with respect to one another and complementary to the first pair of opposed surfaces.

As a complementary feature or an alternative feature, at least one of the barrier-forming elements may comprise an additive layer interposed between the corresponding first and second separation portions.

As a complementary feature or an alternative feature, at least one of the barrier-forming elements may comprise a welded connection of the corresponding first and second separation portions. In the latter case, at least the first and second separation portions of the first and second members may be made of thermoplastic material, the welded connection being made by an ultrasonic welding process.

The device may further comprise a casing provided with a mouthpiece for inhalation by the user, the support being moveably mounted within the casing so as to bring successively each conduit in communication with the mouthpiece.

Furthermore, the support may be of circular configuration, the conduits being adjacent to each other in a circumferential direction, the conduits and the first and second separation portions extending in radial directions, and the support may be rotatably mounted within the casing with respect to a central axis.

The first member may consist in a first concave plate provided with a plurality of through-holes forming the first conduit portions, said through-holes being delimited by radial walls as the first separation portions, the first concave plate being adapted to accommodate the carrier in its concavity with the through-holes in correspondence respectively with the housings

In a similar way, the second member may consist in a second concave plate provided with a plurality of channels having each an inlet and an outlet and forming the second conduit portions, said channels being delimited by radial walls as the second separation portions, the second concave plate accommodating the first concave plate in its concavity, such that the first concave plate is interposed between the second concave plate and the carrier, with the channels in communication respectively with the through-holes.

The device may comprise two supports respectively for two carriers.

According to a second aspect, the invention concerns an inhaler comprising a device for dispensing a plurality of unitary doses of dry powder as above defined, and at least one carrier having a plurality of housings for respective unitary doses, the carriers being associated with the support.

The carrier may be formed of a plate provided with a plurality of through-holes in which the housings are moveably mounted between a storage position, in which said housing is flush with the carrier, and a discharge position, in which said housing protrudes from the carrier, the device may further comprise an assembly for successively moving each housing from the storage position to the discharge position in which said housing extends within one of the first conduit portions of the first member.

The device may comprise two supports, two carriers being each associated with a respective support.

On the Figures, same references refer to similar or analogous elements.

FIG. 1illustrates an inhaler1from which a user may inhale successively unitary doses2of medicament in the form of dry powder.

The inhaler1of the illustrated embodiment includes a device3for dispensing the unitary doses2and two carriers15, visible in particular onFIGS. 3 and 5, which carry the unitary doses2and which are mounted in the device3.

OnFIG. 1, the device3comprises a casing5presenting a contour with a hump-shaped part5aand a constant-radius shaped part5b.

The casing5is provided with a mouthpiece6, formed integrally with the casing5or as a separate component, arranged substantially at a first end of the constant-radius shaped part5b.

The constant-radius shaped part5bis provided with a slot14, partly visible onFIG. 2, extending from the mouthpiece6to a second end opposite to the first end. A priming lever4extends out of the casing5through the slot14. As it will be apparent from the following description, the priming lever4is mounted so as to rotate around the constant-radius shaped part5b, about a central axis A, along a stroke delimited by the slot14. The user may actuate the priming lever4to prime the device3so that one of the unitary doses2may be inhaled through the mouthpiece6.

The device3includes a window7in one side of the casing5. The window7allows the user to view a counter display8which provides the user with an indication of how many unitary doses2have been dispensed and/or how many unitary doses2remain unused.

An L-shaped mouthpiece cover10may be mounted on the casing5. The mouthpiece cover10comprises long11and short12hollow parts substantially perpendicular to each other. An end of the long part11is rotatably mounted on the casing5in the vicinity of the second end of the constant-radius shaped part5bso that the long11and short12parts may selectively cover or expose, as illustrated onFIG. 1, the slot14, the priming lever4and the mouthpiece6. An actuation rib13, the purpose of which will be explained later, extends centrally in the long part11.

As can be seen onFIG. 2, the casing5is made of two halves assembled to each other to define a housing. The casing5comprises a central shaft64extending within the housing along the central axis A and on which the following components of the device3are mounted:first25aand second25bsupports which each receive one respective of the carriers15,an actuating mechanism60arranged between the first25aand second25bsupports and comprising the priming lever4,a changeover mechanism90, anda counter mechanism140.

With reference toFIGS. 3,4,5and6, one of the carriers15and the first support25aare described, by way of example. This description can be transposed to the other carrier15and to the second support25b, these being identical or at least similar to the described carrier15and first support25a.

As can be seen onFIGS. 3 and 5, the carrier15, similar to that disclosed in WO-A-2005/002654, is formed from a disc-shaped plate16having an axis and a central opening17. The plate16is provided with a plurality of through-holes18extending between top and bottom surfaces of the plate16and defining housings for the respective unitary doses of dry powder. In the illustrated embodiment, thirty through-holes18are arranged at equally spaced locations, according to a circumferential array. The through-holes18are hence adjacent to each other in a circumferential direction and extend in radial directions with respect to the axis of the plate16.

One location of the plate16is deprived of a through-hole, so that a full portion19is formed between two adjacent through-holes18. An indent20is formed at the periphery of the plate16in correspondence with this full portion19.

Each through-hole18may receive a cup-shaped insert21, visible in particular onFIGS. 7 and 8, opening in the top surface of the plate16. Each insert21is adapted to contain one of the unitary doses2of dry powder. To protect the dry powder, especially from humidity and contaminants, and to retain the inserts21and the dry powder in the through-holes18, appropriate top22and bottom23lidding sheets may be secured to the top and bottom surfaces of the plate16.

The first support25ais of circular configuration with respect to an axis and has first and second members, consisting respectively of an anvil plate26and an airway plate27.

As can be seen onFIG. 3which shows a top surface of the anvil plate26, the anvil plate26comprises a disc-shaped part28pierced with a central opening32. The disc-shaped part28is provided with successive through-holes29adapted to be placed in correspondence respectively with the through-holes18of the carrier15. As for the carrier15, the though-holes29are adjacent to each other in a circumferential direction and extend in radial directions with respect to the axis of the first support25a. The disc-shaped part28is provided with radial walls30each extending in a radial direction and each arranged between two adjacent through-holes29so as to separate them.

OnFIG. 4, it can be seen that each radial wall30of the disc-shaped part28of the anvil plate26has a rib31protruding on the top surface of the anvil plate26. Each rib31has a rectangular cross-section and a radial dimension which corresponds substantially to that of the adjacent through-holes29.

The anvil plate26also has a securing element for attachment of the top surface of the anvil plate26to the airway plate27. In the illustrated embodiment, a recessed portion39surrounding the central opening32is formed on the disc-shaped part28to cooperate with a securing element of the airway plate27.

As can be seen onFIG. 5which shows a bottom surface of the anvil plate26, the anvil plate26is generally concave with a concavity formed on its bottom surface. For example, the anvil plate26is provided with an annular lateral wall33adapted to surround the external periphery of the carrier15so as to accommodate the carrier15in the concavity of the anvil plate26. In particular, the lateral wall33extends perpendicularly to an outer edge of the disc-shaped part28.

Internally, the lateral wall33is provided with a coupling portion formed, for example, of gear teeth34protruding toward the axis of the first support25a, and with a decoupling portion formed, for example, of a smooth part35arranged locally and deprived of a gear tooth. The lateral wall33also has a protrusion36extending toward the axis and adapted to be received in the indent20of the carrier15.

Externally, the lateral wall33is provided with an engaging portion formed, for example, of gear teeth37arranged locally and protruding opposite to the axis.

The appropriate relative arrangement of the coupling and decoupling portions, of the protrusion36and of the engaging portion will become apparent from the following description of the device3.

The anvil plate26also has a securing element for attachment of the carrier15to the bottom surface of the anvil plate26. In the illustrated embodiment, the bottom surface comprises a mounting skirt38extending perpendicularly from the disc-shaped part28and adapted to be fitted in the central opening17of the carrier15.

Regarding the airway plate27, as can be seen onFIG. 3which shows a top surface of the airway plate27, it comprises a disc-shaped part40pierced with a central opening41. The disc-shaped part40is provided with successive pairs of through-holes42,44adjacent to each other in a circumferential direction. The through-holes42,44of each pair of through-holes extend in a radial direction with respect to the axis of the first support25aand are adapted to be placed in correspondence with one of the through-holes29of the anvil plate26.

As can be seen onFIG. 5which shows a bottom surface of the airway plate27, the disc-shaped part40is provided with successive channels43and with radial walls45arranged so that the channels43and the radial walls45of the airway plate27may face respectively the through-holes29and the radial walls30of the anvil plate26. The channels43are adjacent to each other in a circumferential direction. Each channel43extends in the radial direction between one pair of the through-holes42,44so as to form an inlet42, close to the axis of the first support25a, and an outlet44, at a distance from the axis of the first support25a, for the channel43. Each radial wall45extending in a radial direction is arranged between two adjacent channels43so as to separate them.

The airway plate27is generally concave with a concavity formed on its bottom surface adapted to accommodate the anvil plate26, such that the anvil plate26is interposed between the airway plate27and the carrier15. For example, the airway plate27is provided with an annular lateral wall47adapted to surround the lateral wall33of the anvil plate26. In particular, the lateral wall47extends perpendicularly to an outer edge of the disc-shaped part40. The lateral wall47presents an outer smooth contact surface48and a notch49extending locally from a free edge of the lateral wall47.

In the illustrated embodiment, the securing element for attachment of the airway plate27to the top surface of the anvil plate26comprises a mounting flange50surrounding the central opening41and adapted to be fitted in the recessed portion39of the anvil plate26.

OnFIG. 6, it can be seen that each radial wall45of the disc-shaped part40of the airway plate27has a groove46formed in the bottom surface of the airway plate27. Each groove46of rectangular cross-section is adapted to receive the rib31protruding on the corresponding radial wall30of the anvil plate26.

FIG. 7illustrates the above disclosed anvil plate26and airway plate27assembled to form the first support25ain which one of the carrier15is received.

From the above, the anvil plate26and the airway plate27are secured to one another with the bottom surface of the airway plate27in contact with the top surface of the anvil plate26, and the mounting flange50of the airway plate27fitted in the recessed portion39of the anvil plate26. The lateral wall47of the airway plate27surrounds the lateral wall33of the anvil plate26. As apparent fromFIG. 2, the gear teeth37of the engaging portion of the anvil plate26extend in the notch49of the airway plate27.

The channels43of the airway plate27are in communication respectively with the through-holes29of the anvil plate26. In particular, the inlet42of each channel43communicates with one side of its corresponding through-hole29whilst the outlet44communicates with the opposite side of the corresponding through-hole29.

The through-holes29of the anvil plate26and the channels43of the airway plate27form respectively first and second conduit portions which together define a plurality of conduits adapted to be connected respectively to the housings of the carrier15. The conduits are adjacent to each other in the circumferential direction and extend in radial directions with respect to the support25. The radial walls30of the anvil plate26and the radial walls45of the airway plate27form respectively first and second separation portions interposed between the conduits.

The carrier15is mounted within the first support25awith the top lidding sheet22in contact with the bottom surface of the anvil plate26, and the central opening17of the carrier15fitted on the mounting skirt38of the anvil plate26. The lateral wall33of the anvil plate26surrounds the periphery of the carrier15with the protrusion36of the anvil plate26placed in the indent20of the carrier15, thereby providing an appropriate positioning of the through-holes18and the full portion19of the carrier15with respect to the conduits of the first support25a. In this regard, it will be appreciated that each housing of the carrier15has its own conduit formed in the first support25a, the conduit being adapted to define a flow path for an airstream carrying the unitary dose through inhalation by a user.

In relation toFIGS. 7 and 8, a dispensing process of one of the unitary doses2of dry powder contained in one insert21is disclosed.

OnFIG. 7, the insert21is in a storage position in which it is fully contained in the through-hole18of the carrier15and flush with the top surface of the carrier15. The insert21faces the conduit of the first support25a.

As shown onFIG. 8, by pushing the insert21from the side of the bottom lidding sheet23, it is possible to move the insert21outwardly to a discharge position, in which the insert21protrudes from the top surface of the carrier15and extends in the through-hole29of the anvil plate26. The insert26used to outwardly burst through the top lidding sheet22is still held securely in place. In this respect, the anvil plate26can be used to improve the predictability of the rupture of the top lidding sheet22.

In the discharge position, the insert21within the conduit faces the inlet42of the channel43. In this way, when the user inhales through the mouthpiece6of the device3, an airstream, illustrated by an arrow onFIG. 8, may be drawn through the airway plate27such that it passes through the inlet42down into the insert21, back up into the channel43and then out of the outlet44. The unitary dose of dry powder in the insert21is thus picked up by the airstream, removed from the insert21and carried out of the first support25a.

Suitable dimensions and shape of the conduits to ensure the dry powder is picked up, and where needed deaggregated, may resume that disclosed in WO-A-2005/002654. Besides, as in WO-A-2005/002654, a second flow path which bypasses the insert21may be provided to increase the overall cross sectional area available through which to inhale, and to control the overall flow resistance of the device so that it is comfortable for the user to inhale through. This second flow path may be formed by walls of the casing5.

As can be seen onFIG. 9, in the first support25a, when the anvil plate26and the airway plate27are assembled, the ribs31on the radial walls30of the anvil plate26are placed within the grooves46of the radial walls45of the airway plate27.

Therefore, even if small gaps exist at the interface between the radial walls30,45delimiting respectively the through-holes29of the anvil plate26and the channels43of the airway plates27, for example because these radial walls30,45are not closely tightened, the arrangement of ribs31and grooves46provides a circuitous path between two adjacent conduits.

In the case where the first and second unitary doses2of dry powder are placed in communication respectively with adjacent first and second conduits, the airstream created in the second conduit through inhalation by the user to pick up the second unitary dose2will draw the dry powder of the second unitary dose2without drawing that of the first unitary dose since the arrangement of rib31and groove46between corresponding radial walls30,45of the anvil plate26and of the airway plate27inhibits dry powder of the first unitary dose2from passing from the first conduit to the adjacent second conduit.

This situation may arise when the user actuates the device, thereby moving the insert21containing the first unitary dose2in the discharge position, and is distracted before inhaling the first unitary dose2. Subsequently, the user actuates the device once again, forgetting that he actuated it previously, thereby moving the insert21containing the second unitary dose2into the discharge position.

The rib31and the groove46of two facing radial walls of the anvil plate26and the airway plate27form barriers to the dry powder of the adjacent conduits, limiting thereby cross-dossing, i.e. the amount of dry powder inhaled when the previous unitary dose has been missed or untaken.

For example, in the device disclosed in WO-2005/002654 deprived of barrier-forming elements such as the above described rib and groove arrangement, it has been found that the cross-dosing could reach 150% or more of the nominal unitary dose, that is an excess of 50% or more of dry powder of the previous unitary dose may be inhaled when the subsequent unitary dose is inhaled.

The use of barrier-forming elements according to the invention aims to reduce cross-dosing to 135% or less. In particular, a cross-dosing of less than 115% can be obtained with the barrier-forming elements of the invention.

Of course, the barrier-forming elements are not limited to the above described rib and groove arrangement. For example, the ribs31could be arranged on the airway plate27and the grooves46could be arranged on the airway plate26.

Besides, in the above described embodiment, the barrier-forming elements form a baffle54between the corresponding radial walls30,45of the anvil plate26and the airway plate27providing a circuitous path between two adjacent conduits. Therefore, the barrier-forming elements may comprise any angled or curved interface between the corresponding walls30,45of the anvil plate26and the airway plate27.

In particular, the barrier-forming elements may comprise more than one rib31and one groove46.

For example, as illustrated onFIG. 10, each radial wall30of the anvil plate26is provided with one radial rib131and one radial groove146adapted to cooperate respectively with one radial groove146and one radial rib131of the corresponding radial wall45of the airway plate27. Besides, onFIG. 10, each rib131includes a first pair of opposed surfaces inclined with respect to one another, and each groove146includes a second pair of opposed surfaces inclined with respect to one another and complementary to the first pair of opposed surfaces of the corresponding rib131.

FIG. 11illustrates an alternative embodiment of the barrier-forming elements in which an additive layer52is interposed between the corresponding radial walls30,45of the anvil plate26and the airway plate27. Any appropriate gasket or adhesive in any appropriate pattern, such as continuous layers, discrete points or other, could be used an additive layer.

Besides, as shown onFIG. 12, in another alternative embodiment, the barrier-forming elements may comprise a welded connection between the corresponding radial walls30,45of the anvil plate26and the airway plate27. In this embodiment, the radial walls of the anvil plate26and the airway plate27, or the anvil plate26and the airway plate27themselves, are made of thermoplastic material and are configured to permit the corresponding radial walls30,45to be joined by an ultrasonic welding process. For example, a tipped protrusion or energy director53is arranged on the rib231and abuts the bottom surface of the groove246. The relative movement of the anvil plate26and the airway plate27caused by ultrasonic vibrations will cause the thermoplastic material to melt and the radial walls30,45to be welded.

The barrier-forming elements may implement one of the above disclosed embodiments or may combine several of them.

The invention is not limited to a device as above disclosed. For example, the device could comprise only one support25for one carrier15or more than two supports25for more than two carriers. The supports could be of different types and otherwise moveable with respect to the casing. Many aspects of the present invention are applicable to devices with appropriate supports for housing a wide variety of different carriers. In particular, many of the features of the embodiment described below can be used with carriers having a blister pack construction or with carriers having various arrays of housing.

As can be seen onFIG. 2, within the casing5, the first25aand second25bsupports with their respective carriers15are superposed and arranged coaxially to the central axis A, the bottom surfaces of the carriers15facing each other. The first25aand second25bsupports are rotatably mounted within the casing5about the central axis A so as to bring successively each conduit in communication with the mouthpiece6, thus sequentially connecting the housings to the mouthpiece.

The actuating mechanism60, illustrated in detail onFIG. 13, is arranged between the bottom surfaces of the carriers15. The actuating mechanism60is adapted to expose one of the unitary doses2of dry powder such that it may be carried with the airstream out of the mouthpiece6each time the priming lever4is actuated.

In particular, the actuating mechanism60comprises a dispensing mechanism adapted to expose each unitary dose2to the corresponding conduit, and an indexing mechanism adapted to place each conduit in communication with the mouthpiece6.

The actuating mechanism60comprises a disc-shaped chassis61which supports the dispensing mechanism and the indexing mechanism. The chassis is fixed to the casing5and comprises a hollow pivot shaft65fitted on the shaft64of the casing5. At a location, the chassis comprises guide members71extending axially and defining a radial aperture between them.

The actuating mechanism60further comprises a priming member62bearing the priming lever4and rotatable about the central axis A so as to operate the dispensing mechanism and the indexing mechanism when the priming lever4is actuated.

An example of a suitable priming member62is disclosed in WO-A-2005/002654. The priming member62is formed of a disc-shaped plate moulded in plastic and having a central pivot opening66by which it is rotatably supported on the pivot shaft65of the chassis61.

In the illustrated embodiment, the dispensing mechanism is adapted to move each insert21of each carrier15from its storage position to its discharge position. Again, an example of a suitable dispensing mechanism, implementing prodgers69mounted on the priming member62, and cam surfaces68,75arranged on the priming member62and adapted to move the prodgers69axially, is disclosed in WO-A-2005/002654.

In particular, the dispensing mechanism includes an elongate cam member67formed on the priming member62and separated from the remaining part of the priming member62by elongate openings70through which the abutment members71of the chassis61extend. The cam member67extends in a circumferential direction and presents a profile adapted to provide a limited amount of flexibility. The central cam surface68is provided on each of two opposite sides of the cam member67. Besides, the lateral cam surfaces75extend on either side of the priming member62, in circumferential directions along the elongate openings70, opposite the cam member67.

The prodgers69are identical to each other and clip together with the cam member67between them. Each prodger69has arms73extending perpendicularly to a central part arranged to cooperate with the central cam surface68of the cam member67. The arms73extend through the elongate openings70of the priming member62, and have features72arranged at their ends to contact the lateral cam surfaces75of the priming member62.

The elongate openings70of the priming member62and the guide members71on the chassis61are arranged to hold the prodgers69rotationally but to allow them to move in an axial direction of the device3, towards and away from the carriers15by means of the central68and lateral75cam surfaces that positively guide the prodgers69.

As explained in WO-A-2005/002654, the actuating mechanism60arranges for one of the prodger69to be in alignment with one of the insert21of the corresponding carrier15while the other prodger69faces the full portion19of the other carrier15. In this way, the dispensing mechanism only dispenses one unitary dose2of one of the carrier15at a time.

Operation of the dispensing mechanism is now described.

Movement of the priming lever4in the slot14of the casing5along its stroke from a first position close to the mouthpiece6to a second position at a distance from the mouthpiece6primes the device3to expose the unitary dose2of dry powder to the corresponding conduit.

At an initial step, when the user moves the mouthpiece cover10to expose the mouthpiece6, the priming lever4is in its first position and both prodgers69are in a retracted position at one end of the cam member67opposite the central cam surfaces68.

When the user moves the priming lever4to its second position, the priming member62is rotated relative to the chassis61. The cam surfaces68of the cam member67engage the prodgers69, respectively. The cam surface68that engages the prodger69in alignment with one of the insert21presses out this prodger69so that this prodger69is moved outwardly towards its corresponding carrier15, penetrates the through-hole18of the carrier15and pushes the insert21in the discharge position. Meanwhile, the cam surface68that engages the prodger69in alignment with the full portion19deforms thanks to its flexibility.

After the user has inhaled the unitary dose2, the mouthpiece cover10may be rotated back by the user. The actuation rib13of the mouthpiece cover10may engage the priming lever4to move it back to its first position. The lateral cam surfaces75of the priming member62retract the prodgers69.

The indexing mechanism will now be described.

In the illustrated embodiment, the indexing mechanism is adapted to move the first25aand second25bsupports in successive active positions in each of which one of the conduits is connected to the mouthpiece6so that the corresponding unitary dose2may be carried by the airstream through the mouthpiece6. An example of a suitable indexing mechanism implementing an intermittent motion mechanism is disclosed in WO-A-2005/002654.

In particular, the indexing mechanism comprises a Geneva wheel76rotatably mounted within the casing5about an axis parallel to the central axis A. The Geneva wheel76includes a peg wheel77adapted to cooperate with the priming member62so that the Geneva wheel rotates through an angle of 120° each time the priming lever4is actuated. The Geneva wheel76also includes two gears78coaxial with the peg wheel77and adapted to cooperate respectively with the coupling portions of the first25aand second25bsupports.

The peg wheel77has three long pegs79and three short pegs80arranged alternately at intervals of 60° around its edge.

The indexing mechanism further comprises a driving member81formed on an outer edge of the priming member62. The driving member81is arranged so that:when the priming lever4is moved from its first position to its second position so that, as explained above, the dispensing mechanism pushes the insert21in the discharge position, the driving member81does not rotate the Geneva wheel76,when the priming lever4is moved back from its second position to its first position, the driving member81rotates the Geneva wheel76.

In particular, the driving member81is placed, in the circumferential direction, next to a portion of the priming member62comprising the dispensing mechanism.

The driving member81is provided with a leading portion82, a ratchet pawl83which slopes downward toward the leading portion82, and a slot84with a trailing edge85arranged in sequence.

The operation of the indexing mechanism will now be described in relation to one cycle defined by the movement of the priming lever4as it is actuated by the user. The terms “first”, “second” and “third” related to the long79and short80pegs in the following description are used in relation to one cycle. It should be understood that the “first”, “second” and “third” pegs would change in a subsequent cycle.

As indicated above, when the priming lever4is moved from its first position to its second position, the driving member81does not rotate the Geneva wheel76. In particular, the peg wheel77and the driving member81are arranged so that the outer edge of the priming member62passes over the first of the short pegs80and slides against the first and second of the long pegs79adjacent on either side of the first short peg80, the ratchet pawl83deforming when passing over the second short peg80. The peg wheel76is therefore prevented from rotating.

When the priming lever4returns from its second position to its first position, the leading portion82passes over the first short peg80and the outer edge of the priming member62slides against the first and second long pegs79, thereby preventing the peg wheel77from rotating. Then the ratchet pawl83engages with the first short peg80so that the peg wheel77is driven around, the second long peg79entering the slot84. As the ratchet pawl83disengages the first short peg80, the trailing edge85of the slot84engages the second long peg79and continues to drive the peg wheel77around. As the trailing edge85of the slot84disengages the second long peg79, the outer edge of the priming member62passes over the second of the short pegs80adjacent to the second long peg79and abuts against the second and third of the long pegs79.

The indexing mechanism causes one of each carrier15to be incremented by one unitary dose2each time the priming lever4is actuated.

The gear teeth34of the coupling portion of each airway plate27may be in engagement with the corresponding gear78of the Geneva wheel76so as to be moved with respect to the casing5successively in the active positions. The numbers of gear teeth34on the airway plates34and gears78are arranged so that the motion of an angle of 120° of the Geneva wheel76increments the support25exactly one conduit pitch.

Therefore, the indexing mechanism rotates successively each support25to the next position in which one of the conduit is in communication with the mouthpiece6and the prodger69is aligned with a new insert21. The above described operation of dispensing the unitary dose can then be repeated.

To avoid having both first25aand second25bsupports driven simultaneously, the indexing mechanism is caused initially to drive the first support25aand, when this has had all of its unitary doses2dispensed, to then drive the second support25b.

The first25aand second25bsupports are configured, in particular through the appropriate relative arrangement of the coupling and decoupling portions, of the protrusions36and of the engaging portions of the first25aand second25bsupports, so that the device3presents:a first dispensing state, in which the first support25ais in engagement with the Geneva wheel76of the indexing mechanism so as to be moved with respect to the casing5in each active position, and the second support25bis disengaged from the Geneva wheel76of the indexing mechanism so as to be stationary with respect to the casing5,a subsequent second dispensing state, in which the second support25bis in engagement with the Geneva wheel76of the indexing mechanism so as to be moveable with respect to the casing5in each active position, and the first support25ais disengaged from the Geneva wheel76of the indexing mechanism so as to be stationary with respect to the casing5.

In this respect, it is arranged that the decoupling portion of the airway plate27of one of the first25aand second25bsupports faces the corresponding gear78of the Geneva wheel76, while the gear teeth34of the coupling portion of the airway plate27of the other of the first25aand second25bsupports engage the corresponding gear78of the Geneva wheel76. As a result, with its decoupling portion, the airway plate27may be disengaged from the gear78of the Geneva wheel76so that rotation of the Geneva wheel76does not rotate the support25.

Besides, the decoupling portion and the protrusion36of each of the first25aand second25bsupports are arranged so that when the decoupling portion faces the gear78of the Geneva wheel76, the prodger69faces the full portion19of the carrier15and no unitary dose of this carrier15can be dispensed. Thus, as the indexing mechanism drives the first support25a, in the first dispensing state of the device3, the second support25bremains stationary with respect to the casing5, in an inactive position in which there is no connection between any unitary dose of the carrier15of this second support25band the mouthpiece6. And subsequently, as the indexing mechanism drives the second support25b, in the second dispensing state of the device3, the first support25aremains stationary with respect to the casing5, in an inactive position in which there is no connection between any unitary dose of the carrier15of this first support25aand the mouthpiece6.

The embodiment described above is arranged to dispense the dry powder from each insert21of one carrier15and then subsequently the dry powder from each insert21of the other carrier15. However, it should be appreciated that it is also possible for a device to dispense dry powder from inserts21alternately from one carrier15and then the other carrier15. Alternatively, inserts21of both carriers may be dispensed simultaneously.

FIGS. 14,15,16and17illustrate the changeover mechanism90provided to cause the device3to pass from the first dispensing state to the second dispensing state.

In the illustrated embodiment, the changeover mechanism90is formed of an integral changeover component91, made in one piece, for example by moulding, having first92and second93sides that extend along an axis in opposite directions from a plate94.

OnFIGS. 14 and 15, the first side92of the changeover component91comprises an axle96and a first engaging section95formed, in the illustrated embodiment, of first95a, second95band third95cgear teeth arranged in sequence along an arc.

The first gear tooth95aextends from the axle96in a radial direction to a free end that presents an end surface97substantially perpendicular to the radial direction of the first gear tooth95a. The first gear tooth95ahas thus a limited length in the radial direction with respect to that of the second95band third95cgear teeth. Besides, the first gear tooth95ahas a height along the axis of about one half of that of the second95band third95cgear teeth.

The second gear tooth95bextends from the axle96in a radial direction to a free end presenting a lower engaging profile98, close to the plate94, of a height substantially similar to that of the first gear tooth95a, and an upper profile99. The upper profile99comprises two end surfaces angled with respect to each other, one first100substantially parallel to the end surface97of the first gear tooth95aand offset toward the axle96with respect to this end surface97, the other second101substantially perpendicular to the radial direction of the second gear tooth95b.

In a similar manner, the third gear tooth95cextends from the axle96in a radial direction to a free end presenting a lower engaging profile102, close to the plate94, of a height substantially similar to that of the first gear tooth95a, and an upper profile103presenting an end surface104substantially perpendicular to the radial direction of the third gear tooth95c.

The first side92of the changeover component91further comprises a tab106extending substantially perpendicularly to the first gear tooth95aand tangentially to the axle96, in a direction opposite to the engaging section95. The tab106presents an abutting surface105substantially in alignment with the first end surface100of the second gear tooth95b.

OnFIGS. 16 and 17, the second side93of the changeover component91comprises an axle110and a second engaging section115formed, in the illustrated embodiment, of first115a, second115band third115cgear teeth arranged in sequence along an arc. As can be seen onFIGS. 14 and 16, the first115a, second115band third115cgear teeth of the second side93are substantially axially aligned respectively with the first95a, second95band third95cgear teeth of the first side92.

The first gear tooth115aextends from the axle110in a radial direction to a free end that presents an engaging profile116.

The second gear tooth115bextends from the axle110in a radial direction to a free end presenting a lower engaging profile117, close to the plate94, and an upper profile118. The upper profile118has an end surface120substantially perpendicular to a radial direction along which the third gear tooth115cextends.

The third gear tooth115cextends from the axle110to a free end presenting a lower profile121, close to the plate94, and an upper profile122. The lower profile121presents an end surface123substantially perpendicular to the radial direction of the third gear tooth115c. The upper profile122also presents an end surface125substantially perpendicular to the radial direction of the third gear tooth115c, the end surface125of the upper profile122being offset toward the axle110with respect to that of the lower profile121and being in alignment with the end surface120of the upper profile118of the second gear teeth115b.

The second side93of the changeover component91further comprises a tab129extending from the axle110next to the third gear tooth115cin a radial direction. The tab129presents an abutting surface130substantially in alignment with the end surfaces120,125of the upper profiles118,122of the second115band third115cgear teeth.

As can be seen onFIG. 18, the changeover component91is arranged between the first25aand second25bsupports and rotatably mounted within the casing5with its axis parallel to the central axis A. For example, a casing135, visible onFIG. 13, may be formed in one piece with the chassis61of the actuating mechanism to rotatably support the changeover component91.

The first92and second93sides of the changeover component91cooperate respectively with the first25aand second25bsupports.

In particular, the gear teeth95a,95b, and95cof the first side92of the changeover component91are adapted to mesh with the gear teeth37of the engaging portion of the first support25a. And the gear teeth115a,115b, and115cof the second side93of the changeover component91are adapted to mesh with the gear teeth37of the engaging portion of the second support25b.

The engaging portion of the first support25ais arranged so as to engage the engaging section of the first side92of the changeover component91after the last unitary dose2of the first support25ahas been dispensed and while the first support25ais disengaging from the indexing mechanism, i.e. the indexing mechanism moves the first support25aso as to disengage its coupling portion and to face its decoupling portion. The engaging portion of the first support25aremains engaged with the engaging section of the first side92of the changeover component91in the second dispensing state of the device. And the engaging portion of the second support25bis arranged so as to engage the engaging section of the second side93of the changeover component91after the last unitary dose2of the first support25ahas been dispensed and while the first support25ais disengaging from the indexing mechanism. The engaging portion of the second support25is engaged with the engaging section of the second side93of the changeover component91in the first dispensing state of the device.

The changeover component91is therefore adapted to place the gear teeth34of the coupling portion of the second support25binto engagement with the corresponding gear78of the indexing mechanism while the other gear78of the indexing mechanism moves the first support25aso as to face its decoupling portion, thereby disengaging the first support25afrom the indexing mechanism.

Furthermore, the first end surface100borne by the second gear tooth95band the abutting surface105of the tab106of the first side92of the changeover component91form a first abutting section adapted to cooperate with the contact surface48of the first support25a. And the end surfaces120,125borne by the second115band third115cgear teeth and the abutting surface130of the tab129of the second side92of the changeover component91form a second abutting section adapted to cooperate with the contact surface48of the second support25b.

The abutting sections of the first and second sides are arranged at opposite location with respect to the corresponding first95and second115engaging sections, whereas first95and second115engaging sections are arranged at a same location. Reasons of such arrangement will become apparent from the following description of the operation of the changeover component91.

The description of this operation is now made in relation toFIGS. 19a,19b,20a,20b,21aand21b.

OnFIG. 19a, in the first dispensing state of the device, whilst the first support25ais in engagement with the indexing mechanism, the gear78of the Geneva wheel76meshing with the coupling portion of the first support25a, the first support25ais rotated, as shown by an arrow, successively in the active positions so that the unitary doses of the carrier15mounted in the first support25amay be dispensed. Meanwhile, the second support25bis locked in the inactive position.

Actually, until the first support25ahas reached last active position, the changeover component91is prevented from rotating because the first end surface100of the second gear tooth95band the abutting surface105of the tab106of the first side92abut the contact surface48of the first support25a, shown in chain dotted line. Thanks to the limited length and height of the first tooth95aand to the limited length of the upper profile of second tooth95b, these first95aand second95bteeth do not interfere with the first support25a.

OnFIG. 19b, at this same step, the first115aand second115bgear teeth of the second side93of the changeover component91meshes with gear teeth37of the engaging portion of the second support25through the notch49. Since the changeover component91cannot rotate, the second support25bis also prevented from rotating.

OnFIG. 20a, after the last active position has been indexed on the first support25aand the last unitary dose2has been dispensed, the indexing mechanism moves the first support25aso that the first support25adisengages the indexing mechanism, the decoupling portion35being brought in correspondence with the gear78of the Geneva wheel76. The first support25ais driven to the inactive position. At the same time, thanks to the appropriate positioning of the decoupling portion35and the engaging portion, the notch49of the first support25afaces the first end surface100of the second gear tooth95bof the first side92of the changeover component91, thereby removing the rotational constraint on the changeover component91which can rotate.

At this step, the gear teeth37of the engaging portion of the first support25athat protrude into the notch49mesh with the engaging profile of the first gear tooth95aarranged in the path of the engaging portion of the first support25a. While the first support25akeeps on rotating to the inactive position by means of the indexing mechanism, the gear teeth37of the engaging portion of the first support25awhich mesh with the engaging section95of the first side92of the changeover component91rotate the changeover component91as shown by an arrow.

OnFIG. 20b, since the changeover component91is now free to rotate, the gear teeth115a,115band115cof the second side93of the changeover component91that mesh with gear teeth37of the engaging portion of the second support25brotate this second support25b, as shown by an arrow, to space apart its decoupling portion and to place its coupling portion in engagement with the corresponding gear78of the indexing mechanism. Thereby, the second support25bis spaced apart from its inactive position and can be driven to a first active position by the indexing mechanism.

OnFIG. 21b, at the completion of the move illustrated onFIG. 20b, the device is in the second dispensing state. The gear teeth115a,115band115cof the second side93of the changeover component91run out of engagement with the gear teeth37of the engaging portion of the second support25bso that subsequent rotational movement of the second support25bis independent of the changeover component91.

On the next index and all subsequent indexes of the second support25, the changeover component91is prevented from rotating because the end surfaces120,125of the second115band third115cgear teeth and the abutting surface130of the tab129of the second side93of the changeover component91abut the contact surface48of the second support25b, shown in chain dotted line.

OnFIG. 21a, at this step, the third gear teeth95cof the first side92of the changeover component91remains in mesh with the gear teeth37of the engaging portion of the first support25a, thereby preventing this first support25afrom rotating.

Therefore, in the illustrated embodiment, the first and second abutting sections provide the changeover component91with a locking arrangement that:in the first dispensing state of the device3, prevents the changeover component91from rotating with respect to the casing5so that the changeover component91locks the second support25bwhile the first support25ais driven by the indexing mechanism successively between its first and last active positions to dispense the unitary doses2of its carrier15,while the first support25ais disengaging from the indexing mechanism, allows the changeover component91to rotate with respect to the casing5so that the changeover component91releases the second support25band places the second support25binto engagement with the indexing mechanism,in the second dispensing state of the device, prevents the changeover component91from rotating with respect to the casing5so that the changeover component91locks the first support25awhile the second support25bis driven by the indexing mechanism successively between its first and last active positions to dispense the unitary doses2of its carrier15.

The invention is not limited to the above disclosed changeover mechanism90. Any other suitable changeover mechanism90that allows for a reliable locking of the unused support25and for a releasing at a determined moment, when the first support25is in a determined position, to allow the driven support25to be changed, could be provided.

The indexing of the device, in addition to moving the next insert21into alignment with the prodgers, actuates the counter mechanism140that provides a visual indication to the user of how many unitary doses2have been dispensed and/or how may unitary doses2remain unused

An example of a suitable counter mechanism140, implementing a unit and tens counter driven by a driving gear meshing with one of the gears78of the Geneva wheel76of the indexing mechanism, is disclosed in WO-A-2005/002654. The driving gear and the unit and tens counters are adapted to index a tens display of the counter display8of one number as a unit display of the counter display8is indexed from 9 to 0.