Unlted States Patent
`
`[19]
`
`U5005349945A
`[11] Patent Number:
`
`5,349,945
`
` .
`
`Wass et a1.
`
`[45] Date of Patent:
`
`Sep. 27, 1994
`
`[54] AEROSOL DISPENSER COMPRISING AN
`INDICATOR ASSEMBLY
`
`[56]
`
`References Cited
`U.s. PATENT DOCUMENTS
`
`[75]
`
`_
`Inventors: Anthony C. L. Wass, mes; Brian R.
`Law, Leicester, both of United
`Kingdom
`
`[73] ASSignee‘ Minnesma Mining and
`Mimufactuflng Company, St- Paul,
`Minn.
`
`[21] Appl. No.: 790,373
`
`[22] Filed:
`
`Nov. 12, 1991
`
`[30]
`
`Foreign Application Priority Data
`.
`.
`Nov. 26, 1990 [GB] United Kingdom ................. 9025654
`
`Int. Cl.5 ............................................. A61M 11/00
`[51]
`[52] US. Cl. .......................... 128/200.23; 128/200.14;
`128/203,15
`[58] Field of Search ...................... 128/200.14, 200.18,
`128/200.23, 203.12, 203.15; 222/48, 23, 402.1,
`402.13
`
`5,020,527
`
`6/1991 Dessertine ...................... 128/200.23
`
`FOREIGN PATENT DOCUMENTS
`0269496
`6/1988 European Pat. Off.
`.
`1058636 2/1967 United Kingdom .
`1290484
`9/1972 United Kingdom .
`2063075
`6/1981 United Kingdom .
`2191032A 12/1987 United Kingdom .
`W091/O6334 5/1991 World Int. Prop. 0. .
`
`Primary Examiner—Vincent Millin
`Assistant Examiner—Raleigh W. Chin
`Attorney, Agent, or Firm—Gary L. Griswold; Walter N.
`Kim; Dale E. Hulse
`
`[57]
`
`ABSTRACT
`
`An aerosol dispenser for use with an aerosol vial. The
`dispenser contains an assembly that indicates the quan-
`tity of doses dispensed from 01‘ remaining in the aerosol
`vial. The assembly comprises a rotatable indicator com-
`prising a circumferential rack that is engaged by a
`worm-gear. Reciprocal movement of an aerosol vial
`within the dispenser causes rotation of the worm-gear
`which in turn causes rotation of the rack.
`
`16 Claims, 4 Drawing Sheets
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`
`RFC-1006
`
`RPC v Trudell
`
`Page 1 of 10
`
`RPC-1006
`RPC v Trudell
`Page 1 of 10
`
`

`

`US. Patent
`
`Sep. 27, 1994
`
`Sheet 1 of 4
`
`5,349,945
`
`
`
`RFC-1006 / Page 2 of 10
`
`RPC-1006 / Page 2 of 10
`
`

`

`US. Patent
`
`Sep. 27, 1994
`
`Sheet 2 of 4
`
`5,349,945
`
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`RFC-1006 / Page 3 of 10
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`RPC-1006 / Page 3 of 10
`
`
`

`

`US. Patent
`
`Sep. 27, 1994
`
`Sheet 3 of 4
`
`5,349,945
`
`
`
`RFC-1006 / Page 4 of 10
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`RPC-1006 / Page 4 of 10
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`

`

`US. Patent
`
`Sep. 27, 1994
`
`Sheet 4 of 4
`
`5,349,945
`
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`RFC-1006 / Page 5 of 10
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`RPC-1006 / Page 5 of 10
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`
`
`
`

`

`1
`
`AEROSOL DISPENSER COMPRISING AN
`INDICATOR ASSEMBLY
`
`5,349,945
`
`10
`
`15
`
`This invention relates to devices for indicating the 5
`quantity of doses dispensed from and/or remaining in
`an inhalation device and in particular to inhalation de-
`vices by which medicaments contained in a pressurised
`aerosol vial are administered to a patient.
`Certain devices that are operated by a reciprocating
`element, e.g., a button, require the presence of a count-
`ing device in order to provide an indication of the ex-
`tent of use. Known counting devices range from com-
`plex electrical devices providing a visual digital display
`to simple mechanical devices having a sliding scale to
`display the extent of use.
`Inhalation therapy is becoming an increasingly im-
`portant method of administering medicaments to a pa-
`tient. The medicament is formulated with suitable pro-
`pellant and appropriate other components and charged
`in an aerosol vial. The aerosol vial is fitted with a valve
`which generally comprises a metering chamber such
`that each operation of the valve dispenses a predeter-
`mined measured quantity of medicament. The aerosol
`vial is inserted into an adaptor having a mouthpiece or
`a port adapted for nasal use and the medicament is ad-
`ministered by firing the aerosol simultaneously with
`inhalation. Examples of such inhalation devices are the
`MEDIHALER TM and AUTOHALER TM aerosol
`
`20
`
`25
`
`30
`
`35
`
`inhalation devices commercially available from Minne-
`sota Mining and Manufacturing Company.
`With a conventional press-and-breathe device in
`which the patient fires the device by depressing the
`aerosol vial whilst inhaling, a rough indication of the
`amount of medicament remaining in the vial can be
`obtained by shaking the whole unit. With experience,
`the user can distinguish the difference in ‘feel’ between
`a vial that is substantially full and one that is substan-
`tially empty. However, this method is necessarily far
`from precise and is even less satisfactory with a breath
`actuated inhaler in which, because of the additional
`parts, the mass of the aerosol contents is a smaller pro-
`portion of the total unit weight.
`With inhalation devices that utilize an aerosol vial
`initially charged with a known quantity of medicament,
`a metered dose of which is dispensed each time the vial
`is operated, counting the number of operations of the
`valve will give an indication of the total amount of
`medicament dispensed and hence the amount of medica-
`ment remaining in the vial. The metering is normally
`accurate but incorrect actuation of the vial occasionally
`results in a reduced dose. The dose, however, can never
`exceed the predetermined metered quantity. Therefore
`counting the number of doses used is a safe basis for
`computing the number of doses remaining because any
`error will indicate the presence of fewer doses than are
`actually present. It is highly desirable that the patient be
`given an indication that the contents of the vial are
`being depleted before the vial is actually empty and the
`patient attempts to use the empty inhaler at a time when
`the patient is under stress. Accordingly, it is desirable to
`incorporate some form of counting device on the aero-
`sol vial or adaptor which will give an indication before
`the vial is empty.
`A conventional aerosol vial is operated by causing a 65
`valve stem to be depressed relative to the vial body. A
`convenient means of counting the number of discharges
`from the aerosol vial is to convert the reciprocatory
`
`45
`
`50
`
`55
`
`2
`movement of the valve stem into one-way movement of
`some form of indicator. If the number of doses con-
`tained within the Vial were relatively small, it would be
`possible to use the linear movement of the vial to index
`along a simple indicator band and so mark the progres-
`sion from “full” to “empty”. Such a counting means
`need only comprise a ratchet device and a toothed indi-
`cator rack moving in a direction parallel to the recipro-
`cal motion of the valve stem. However, the number of
`doses normally number at least fifty, often two hundred.
`Accordingly, in practice the total linear movement of
`such a rack would be far too great to be accommodated
`in a conventional inhaler unless each incremental step of
`the rack were very small. However, tiny incremental
`steps require firstly that only a small fraction of the total
`reciprocatory movement of the valve stem is converted
`into rack movement and secondly very fine teeth must
`be moulded on both mating parts. These requirements
`are not easy to fulfill economically and on a mass pro-
`duction basis. Even if such fine teeth were readily
`mouldable with such precision, the slightest distortion
`would lead to the indicator rack either not being in-
`dexed at all or indexed by two or more increments for
`a given single actuation. Such an inaccurate counting
`device would serve no useful purpose.
`In an alternative arrangement, the rack can take the
`form of an indicator wheel or a counter ring mounted
`for rotational movement in response to the reciprocal
`movement of the valve stem. The rack can be rotatable
`
`about an axis either transverse or parallel to the direc-
`tion of valve movement.
`
`British Published Patent Application No. 2191032A
`discloses an indicator assembly for use with aerosol
`dispensers of the press-and-breathe type comprising a
`housing mounted on the exterior of the dispenser and
`defining a compartment containing a ratchet wheel and
`a ratchet wheel driving member movable with the aero-
`sol vial to cause rotation of the ratchet wheel; and a
`rotatable toothed indicator wheel mounted for rotation
`about an axis transverse or substantially transverse to
`the movement of the aerosol via]. The ratchet wheel is
`provided with a spur gear which meshes with the iridi-
`cator Wheel to cause rotation of the same. The indicator
`wheel is provided with suitable markings to provide the
`user with a visual impression of the quantity of doses
`dispensed from the vial. One revolution of the indicator
`wheel would permit much greater total movement
`within the confines of a normal inhaler configuration
`than any purely linear movement. Aerosol vials, how-
`ever, may contain up to 200 doses. It would be difficult
`to provide so many teeth on a small circular rack. It
`would therefore be necessary to reduce the number of
`teeth and allow the rack to rotate through a number of
`revolutions before the aerosol vial was empty. How-
`ever, this arrangement would require some means of
`counting the revolutions of the rack.
`British Patent Specification No. 1290484 discloses an
`aerosol dispenser of the press-and-breath type having an
`indicator assembly comprising two coaxial,
`toothed
`indicator rings spaced in parallel planes and mounted
`for rotation within the dispenser housing about an axis
`substantially parallel to the direction of valve move-
`ment, one of which rings is rotatable by the other at a
`fraction of the rotational displacement thereof; and a
`sleeve slidably mounted within the dispenser housing
`which receives and is movable with the aerosol vial.
`
`Displacement of the aerosol vial at device actuation
`causes the sleeve to engage and rotate one of the two
`
`RFC-1006 / Page 6 of 10
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`RPC-1006 / Page 6 of 10
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`

`

`3
`rings so as to indicate to the user that a dose has been
`dispensed from the vial. At least one of the counter
`rings is provided with markings viewed through a win-
`dow in the dispenser housing to provide a visual indica-
`tion to the user of the quantity of doses dispensed from
`the aerosol vial. However, such a device still relies on
`the relatively coarse movement of the aerosol vial to
`effect rotation of the indicator ring(s). Furthermore, as
`the function of the indicator assembly is simply to give
`an indication to the user when the vial is approaching
`the empty condition, a large amount of rack movement
`is unnecessary. It would be highly desirable to arrange
`that the indicator ring did not move through more than
`one revolution so that one end of the arc of movement
`
`could carry the indication “FULL” and the other end
`of the arc of movement could carry an “EMPTY” indi—
`cation. Heretofore there is no known simple counting
`device meeting these requirements.
`According to the present invention there is provided
`an aerosol dispenser comprising a housing having a
`patient port, the housing being adapted to accommo-
`date an aerosol vial equipped with a metered-dose dis-
`pensing valve that comprises a valve stem movable
`between closed and discharge positions, the dispenser
`further comprising a support block having a socket
`adapted to receive the stem of the valve and an orifice
`having open communication with the socket and the
`patient port, the aerosol vial and support block being
`reciprocally movable relative to each other to cause the
`stem to move to its discharge position, thereby dispens-
`ing a dose from the aerosol vial, the dispenser having an
`indicator
`assembly comprising rotatable indicator
`means to provide an indication of the quantity of doses
`dispensed from or remaining in the aerosol vial, the
`indicator means comprising a circumferential rack and
`being mounted for rotation about an axis parallel or
`substantially parallel to said reciprocal movement of the
`vial and support block; a worm-gear engaging said cir-
`cumferential rack and a movement detecting member
`movable in response to said reciprocal movement of the
`vial and support block, wherein movement of the move—
`ment detecting member in response to said reciprocal
`movement causes rotation of said worm gear and indi-
`cator means.
`
`Indicator assemblies for use in the present invention
`comprise counting devices
`for aerosol dispensers,
`wherein the linear (and often rather coarse) movement
`of an aerosol vial relative to its support block, or vice
`versa, used to dispense a single dose from the vial is
`translated via a worm (reduction) gear into a much
`smaller incremental movement of a rotable indicator
`means to provide a visual indication of the total quantity
`of doses dispensed from, or remaining in, that aerosol
`vial. The conversion of linear to rotary movement to—
`gether with permanent engagement of the worm gear
`and indicator means is found to provide a reliable count-
`ing device.
`While such counting devices can be fitted to a wide
`range of aerosol dispensers, they are most suitable for
`use with metered-dose inhalers, i.e., dispensers that are
`used in connection with a aerosol vial containing a
`self-propelled pharmaceutical formulation comprising a
`medicament, the vial being equipped with a valve that
`dispenses a metered dose of a medicament for inhalation
`by a patient. The counting device can be used with both
`press-and-breathe metered dose inhalers and breath
`actuated metered dose inhalers.
`
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`5,349,945
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`4
`The indicator means generally comprises a circular
`or annular rack. The rack is generally mounted for
`rotation about whichever of the aerosol vial and sup-
`port block is held stationary and is provided with a
`plurality of circumferential, generally equally~spaced
`teeth that mesh with the worm of the reduction gear.
`The teeth can project radially inward or radially out-
`ward. The indicator rack is preferably provided with
`suitable markings to indicate to the patient the quantity
`of doses dispensed from or remaining in the aerosol vial.
`The teeth of the indicator rack preferably include a
`spacer gap and/or a spacer block to halt its rotation at
`a given point or to prevent more than one full revolu-
`tion of the rack.
`The housing of the dispenser can be provided with a
`viewing port through which the indicator means is
`visible. Alternatively the indicator means can be viewed
`through the patient port. In one embodiment the view-
`ing port comprises a window of a transparent, option-
`ally magnifying, material.
`The worm gear generally comprises a shaft bearing a
`worm and having an integral ratchet wheel that is selec-
`tively engaged by the movement detecting member to
`cause rotation of the worm gear. The shaft is normally
`mounted for rotation about an axis transverse or sub-
`stantially transverse to the direction of reciprocal
`movement between the vial and support block. In a
`further embodiment, the worm and ratchet wheel can
`be integrated into a single ‘toothed’ worm. The pitch of
`the worm is selected such that rotary movement of the
`worm-gear produces a much smaller incremental move-
`ment of the indicator means. In this manner, a single
`revolution of the indicator means can cope with an
`aerosol vial containing several hundred doses of medi—
`cament.
`
`The movement detecting member generally com-
`prises a projecting finger that is selectively engageable
`with the ratchet wheel to cause rotation of the ratchet
`
`wheel and hence rotation of the worm gear. In one
`embodiment the finger is fixed relative to whichever of
`the aerosol vial and support block is movable relative to
`the other so that movement causes the finger to engage
`the ratchet wheel. In an alternative embodiment the
`
`projecting finger can be fixed relative to the stationary
`element (e.g., the support block) such that the displaced
`aerosol vial engages and displaces the projecting finger,
`thereby causing it to engage the worm gear. Alterna-
`tively, the movement detecting member can comprise
`the aerosol vial or the support block itself. For example,
`the cap or ferrule of the aerosol vial can, on relative
`movement of the vial, engage and rotate the ratchet
`wheel, thereby rotating the worm gear.
`The indicator assembly can additionally comprise
`means to prevent unwanted movement of the indicator
`means. For example, the assembly can be provided with
`one or more fixed,
`‘non-return’
`fingers to prevent
`‘wrong—way’ rotation of the worm gear and/or the
`indicator means during handling and transport and dur-
`ing return movement of the movement detecting mem-
`ber.
`the indicator assembly is constructed
`Preferably,
`such that the patient (or any other person) cannot
`readily obtain access to the counting device. This pre-
`vents unauthorized or accidental tampering. In addi-
`tion, the assembly is preferably constructed such that
`the aerosol vial can be readily removed from the dis-
`penser housing for cleaning, freeing stem obstructions
`
`RFC-1006 / Page 7 of 10
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`RPC-1006 / Page 7 of 10
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`

`

`5,349,945
`
`5
`etc., without changing the position of the indicator
`means.
`The invention will now be described with reference
`
`to the accompanying drawings in which:
`FIG. 1 is a perspective view of an indicator assembly
`suitable for use with an aerosol dispenser in accordance
`with the invention;
`FIGS. 2 to 5 are perspective views of alternative
`arrangements of indicator assembly for use with aerosol
`dispensers in accordance with the invention;
`FIG. 6 is a vertical section through a breath-actuated,
`metered dose aerosol dispenser in accordance with the
`invention;
`FIG. 7 is a sectional View through the support block
`of the aerosol dispenser shown in FIG. 6 fitted with an
`alternative indicator assembly,
`FIG. 8 is a vertical section through a press-and-
`breathe, metered dose inhaler in accordance with the
`invention,
`FIG 9 is a horizontal section through the support
`block of an aerosol dispenser in accordance with the
`invention,
`FIG. 10 is a vertical section along the axis C—C of
`the support block of FIG. 9, and
`FIG. 11 is a vertical section along the axis D—D of
`the support block of FIG. 9.
`FIGS. 1 to 5 represent a series of closely related
`indicator assemblies with each assembly shown isolated
`from its aerosol dispenser in order to more clearly illus-
`trate the principles underlying the invention. Each as-
`sembly comprises indicator means in the form of a cir-
`cumferential rack, hereinafter referred to as counter
`ring 2 having a plurality of circumferential teeth 4.
`Counter ring 2 is adapted to be rotated about an axis
`parallel or substantially parallel to the linear (recipro-
`cal) movement of the aerosol vial and support block
`(denoted by center line A); and a worm (reduction) gear
`permanently engaging teeth 4 of counter ring 2 and
`adapted to be rotated about an axis transverse or sub-
`stantially transverse to the movement of the vial and
`support block (denoted by centre line B).
`Referring to FIG. 1, the reduction gear comprises
`shaft 6 bearing worm 8 and integral ratchet wheel 10.
`Ratchet wheel 10 is selectively engaged by the move-
`ment detecting member in the form of ‘actuating’ finger
`12, typically located on the aerosol vial or the support
`block, thereby rotating the reduction gear a predeter—
`mined distance. Worm 8 engages teeth 4 of counter ring
`2 and converts the rotation of the reduction gear into
`incremental movement of the counter ring. The indica—
`tor assembly is preferably provided with ‘non-return’
`finger 14 which ensures that the reduction gear is able
`to rotate in one direction only (in thiscase clockwise).
`Thus, linear movement of the aerosol vial can be con-
`verted into unidirectional incremental movement of the
`
`reduction gear which, in turn, is converted into unidi-
`rectional, incremental movement of the counter ring.
`In order to reduce the size of the indicator assembly
`even further, thereby enabling it to be fitted into a wide
`range of commercially available press-and-breathe and
`breath actuated inhalers with the minimum of modifica-
`tions, modifications as illustrated in FIGS. 2—5 have
`been made to the assembly shown in FIG. 1.
`Referring to FIG. 2, the ratchet wheel and the worm
`of the reduction gear have been combined as ‘toothed’
`worm 16 enabling both to be located on the center line
`of the indicator assembly (the actuating and non-return
`fingers have been omitted from the figure for reasons of
`
`5
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`clarity). The use of a combined worm/ratchet wheel
`allows teeth 4 of counter ring 2 to be oriented axially
`about its circumference (see FIG. 3) or radially inwards
`(see FIG. 4). This last arrangement allows the entire
`mechanism to be confined within the circumference of
`counter ring 2.
`Referring to FIG. 5, movement of counter ring 2 can
`be stopped automatically at a position corresponding to
`an ‘empty’ vial by incorporating spacer gap 18 in teeth
`4 of counter ring 2. Further rotation of counter ring 2
`past the empty position can be positively prevented by
`the inclusion of spacer block 20.
`Referring to FIG. 6, a breath actuated aerosol dis-
`penser of the type disclosed in European Patent No.
`147028 and commercially available under the trade
`name AUTOHALER TM aerosol
`inhalation device
`
`from Minnesota Mining and Manufacturing Company
`comprises housing 24 incorporating a patient port, here-
`inafter referred to as mouthpiece 26 enclosed by remov-
`able cover 28 and containing aerosol vial 30. In altema—
`tive embodiments (not shown), dispenser 22 can have an
`integral nasal adapter, or be supplied with both mouth-
`piece and adaptor in an interchangeable format. Aerosol
`vial 30 can be of any suitable size and has a metering
`valve (not shown) possessing hollow valve stem 32.
`Valve stem 32 is located within socket 34 in support
`block 36 which has a passage 38 in communication with
`mouthpiece 26. Discharge of the metering valve is ef-
`fected by relative movement between aerosol vial 30
`and valve stem 32.
`
`The breath actuation mechanism comprises vane 40
`pivotally mounted within mouthpiece 26, and rocker
`element 42 which supports catch 44 pivotally mounted
`on rocker element 42 at 46. When the breath actuation
`
`mechanism is in its blocking, inoperative position, as
`shown in FIG. 6, and a cocking force is applied in the
`direction of arrow ‘A’, the movement of aerosol vial 30
`is prevented. Such movement is blocked by rocker
`element 42 which is itself blocked from pivotal move-
`ment by catch 44 having curved surface 48 engaging
`curved surface 50 of vane 40. Thus, it is not possible to
`dispense the contents of aerosol vial 30 before the pa-
`tient has inhaled through mouthpiece 26.
`When a patient inhales through mouthpiece 26, inha-
`lation causes pivotal movement of vane 40. The fully
`displaced position of vane 40 is depicted in dotted relief
`and denoted by 52. Curved surface 50 of vane 40 and
`curved surface 48 of catch 44 effectively act as cooper-
`ating roller surfaces such that pivotal movement of vane
`40 causes curved surface 50 of vane 40 to rotate in one
`
`direction resulting in curved surface 48 of catch 44
`rotating in the opposite direction. Catch 44 is displaced
`from a blocking to an unblocking position allowing for
`pivotal movement of rocker element 42 which, in turn,
`allows movement of aerosol vial 30 relative to valve
`
`stem 32 under the influence of the cocking pressure,
`thereby causing the valve to fire. Rocker element 44 is
`biased, e.g, by a spring, to the home (blocking) position
`when patient inspiration is halted.
`Dispenser 221s fitted with an indicator assembly to
`provide an indication of the quantity of doses dispensed
`from and/or the quantity of doses remaining in vial 30.
`The indicator assembly comprises: counter ring 2 hav-
`ing a plurality of circumferential teeth 4 and mounted
`for rotation about support block 36 with no appreciable
`axial movement thereof, the axis of rotation being sub-
`stantially the same as the longitudinal axis of aerosol
`vial 30; and a reduction gear comprising shaft 6 bearing
`
`RPC-1006 / Page 8 of 10
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`RPC-1006 / Page 8 of 10
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`

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`5,349,945
`
`7
`worm 8 and having at one end thereof integral ratchet
`wheel 10, shaft 6 being mounted for rotation about an
`axis transverse to the longitudinal axis of aerosol vial 30.
`Rocker element 42 is provided with actuating finger 12
`which selectively engages ratchet wheel 10 upon dis-
`placement of element 42 during each actuation of dis-
`penser 22 as described above, thereby causing the re-
`duction gear to rotate a predetermined amount. Worm
`8 engages teeth 4 of counter ring 2 and converts rota-
`tion of the reduction gear into incremental movement of
`counter ring 2. Support block 36 is provided with a
`flexible ‘non—return’ finger 14 which engages ratchet
`wheel 10 of the reduction gear to prevent unwanted
`(clockwise) rotation of the same during the return
`stroke of actuating finger 12, or in the course of han-
`dling and transport.
`Suitable indicator markings are provided on the side
`of counter ring 2 which can be viewed through trans-
`parent window 54 in housing 24 to provide the patient
`with an indication of the contents remaining. For exam-
`ple, the counter ring can be numerically marked with
`each actuation, either descending to represent the quan-
`tity of doses remaining, or ascending to represent the
`quantity of doses used, with the present dosage being
`viewed
`through the
`housing window. A vial
`“EMPTY” and optionally a vial “FULL” sign can also
`be provided. In the simplest embodiment, the empty
`status of the vial can be represented by a change in
`colour. For example, the counter ring can be moulded
`in a green material with a vertical red stripe printed
`upon it. Initially, the red stripe would be set just to one
`side of the counter window and as the dispenser is used,
`the stripe is rotated away from the window until it
`eventually approaches it from the other side. As the last
`few doses are used, the red stripe will begin to appear in
`the counter window to indicate to the patient that the
`dispenser is nearly empty. Alternatively, the counter
`ring can be viewed through the mouthpiece.
`Referring to FIG. 7, support block 36 of the aerosol
`dispenser shown in FIG. 6 is provided with a modified
`reduction gear, in which the ratchet wheel and worm
`are combined to produce ‘toothed’ worm 16.
`Referring to FIG. 8, aerosol dispenser 55 comprises
`housing 24 defining inner chamber 56 and having inte-
`gral mouthpiece 26. The dispenser additionally com-
`prises aerosol vial 30 displaceably mounted within
`chamber 56 so that valve stem 32 abuts support block
`36. The support block communicates with mouthpiece
`26 through connecting passage 58 and valve stem 32
`through socket 34. In use, mouthpiece 26 is inserted by
`the patient into his/her mouth and aerosol vial 30 fully
`depressed by the application of pressure to the base of
`aerosol vial 30 while the patient simultaneously inhales.
`Depression of aerosol vial 30 relative to valve stem 32
`causes a metered dose to exit through support block 36
`to mouthpiece 26. Patient inspiratory effort delivers the
`aerosolised medicament into the patient’s pulmonary
`system. Valve stem 32 is biased, e.g., by a spring (not
`shown), to return aerosol vial 30 to the closed position
`when the displacing pressure is removed.
`Dispenser 55 is provided with an indicator assembly
`comprising adaptor 60 which locates around support
`block 36 to support counter ring 2,
`the ring being
`mounted for rotation about support block 36; and a
`worm (reduction) gear comprising shaft 6 bearing
`worm 8 and ratchet wheel 10. Adaptor 60 is also pro-
`vided with actuating finger 12. Valve stem 32 passes
`through channel 62 in finger 12, which is selectively
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`4O
`
`45
`
`50
`
`55
`
`65
`
`8
`engaged by depressed aerosol vial 30 via lug 64. Actuat-
`ing finger 12, in turn, engages ratchet wheel 10 thereby
`rotating the reduction gear. As described above for the
`dispenser shown in FIG. 6, worm 8 of the reduction
`gear meshes with teeth 4 of counter ring 2 to convert
`rotation of the reduction gear into incremental move-
`ment of the counter ring. Housing 24 is provided with
`‘non-return’ finger 14 to prevent unwanted (counter-
`clockwise) rotation of ratchet wheel 10. In this embodi-
`ment, counter ring 2 is viewed by the patient through
`mouthpiece 26.
`Referring to FIGS. 9 to 11, an alternative arrange-
`ment of indicator assembly is shown for use with the
`aerosol dispenser of FIG. 8. The indicator assembly
`comprises adaptor 60, counter ring 2 mounted for rota-
`tion about the periphery of adaptor 60 and having a
`plurality of circumferential teeth 4, a reduction gear
`comprising shaft 6 bearing worm 8 and having at either
`end thereof ratchet wheel 10 and 66 and a movement
`
`ring—
`detecting member comprising base portion 68,
`shaped portion 70 and two resiliently flexible members
`72 and 74.
`
`Adaptor 60 comprises circular base 76 having central
`boss 78 which is complementary in shape to support
`block 36 of the aerosol dispenser. During assembly,
`adaptor 60 is located about support block 36 as shown in
`FIG. 10 and serves to support the remainder of the
`indicator assembly. Central boss 78 of adaptor 60 is
`provided with channel 62 which allows the valve stem
`of the aerosol vial (not shown) to be inserted into socket
`34 of support block 36.
`Counter ring 2 is formed with peripheral groove 80
`which supports ring 2 on base 76 of adaptor 60 to permit
`rotation thereof. Flange 82 and retaining clips 84 secure
`counter ring 2 in position to prevent unwanted lateral
`and axial movement of the ring.
`Base portion 68 of the movement detecting member is
`pivotally mounted at 86 to permit displacement of the
`member in the direction indicated by the solid arrow
`labelled E (see FIG. 10). When the dispenser is not in
`use, displacement of the movement detecting member
`as indicated is prevented by resiliently flexible members
`72 and 74 which abut support columns 88 and 90.
`Ring shaped portion 70 of the movement detecting
`member extends around central boss 78 and support
`block 36 and is provided with actuating finger 12 which
`is selectively engageable with ratchet wheel 10 of the
`reduction gear and projecting lugs 92 and 94 which are,
`in turn, selectively engageable by the aerosol vial. To
`use the dispenser the patient inserts the mouthpiece (not
`shown) into his or her oral or nasal cavity and depresses
`the aerosol vial relative to the valve stem by the appli-
`cation of pressure to the base of the vial, thereby caus-
`ing a metered dose to exit through support block 36 to
`the mouthpiece. Subsequent patient inspiration delivers
`the aerosolised medicament into the lungs. In this man—
`ner, depression of the aerosol vial by the patient causes
`the vial to engage lugs 92 and 94 of ring-shaped portion
`70 of the movement detecting member, thereby displac—
`ing the member. This enables actuating finger 12 to
`engage ratchet wheel 10 of the reduction gear, thereby
`rotating the reduction gear. Worm 8 of the reduction
`gear meshes with teeth 4 of counter ring 2 to convert
`rotation of the reduction gear into incremental move-
`ment of counter ring 2.
`Displacement of the movement detecting member
`produces an antagonistic tension in resiliently flexible
`members 72 and 74 which on the return of the aerosol
`
`RPC-1006 / Page 9 of 10
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`RPC-1006 / Page 9 of 10
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`

`

`5,349,945
`
`10
`further comprising an integral ratchet wheel which is
`selectively engageable by said movement detecting
`member to rotate the worm—gear, the worm meshing
`with the teeth of the rack to drive the rack upon said
`rotation.
`
`9
`vial to its home position (the displacing pressure having
`been removed) causes the movement detecting member
`to return to its home position.
`Adaptor 60 is provided with a flexible non-return
`finger 14 which engages the other ratchet wheel 66 of 5
`the reduction gear to prevent unwanted rotation of the
`same during the return stroke of actuating finger 12.
`We claim:
`1. An aerosol dispenser comprising a housing having
`a patient port, the housing being adapted to accommo-
`date an aerosol vial equipped with a metered-dose dis-
`pensing valve that comprises a valve stem movable
`between closed and discharge positions, the dispenser
`further comprising a support block having a socket
`adapted to receive a valve stem and an orifice having
`open communication with the socket and the patient
`port,
`the support block being reciprocally movable
`relative to an aerosol vial accommodated within the
`
`10
`
`15
`
`6. An aerosol dispenser according to claim 5 in which
`the worm and ratchet wheel are integral.
`7. An aerosol dispenser according to claim 1 in which
`the movement detecting member comprises a project-
`ing finger fixed relative to one of an aerosol vial accom-
`modated within the housing and said support block and
`selectively engageable with said worm-gear.
`8. An aerosol dispenser according to claim 7 in which
`the projecting finger is fixed relative to the aerosol vial
`and said vial is movable relative to the support block.
`9. An aerosol dispenser according to claim 7 in which
`the projecting finger is fixed relative to the support
`block and said vial is movable relative