WO2016059645A1

WO2016059645A1 - A dose counter

Info

Publication number: WO2016059645A1
Application number: PCT/IN2015/000384
Authority: WO
Inventors: Ashwin Gregory SOARES; Prashant Narayan NAVALE; Saikat De
Original assignee: Cadila Healthcare Limited
Priority date: 2014-10-14
Filing date: 2015-10-13
Publication date: 2016-04-21
Also published as: PH12017500709A1

Abstract

The present invention relates to a dose counter for counting the number of doses of fluid that have been dispensed or that remain to be dispensed from a fluid dispenser device, said counter comprising a cylindrical housing (2), a trigger member (1), a ratchet member (3) and a counter member (4) constructed and arranged to undergo a predetermined counting movement each time a dose is dispensed.

Description

A DOSE COUNTER

FIELD OF THE INVENTION:

The present invention relates to a counter, and more particularly to a dose counter, for indicating to the user the number of doses that have been dispensed or that remain to be dispensed from a dispenser device.

BACKGROUND AND PRIOR ART:

The use of inhalation devices in the administration of medicaments, for example in bronchodilation therapy is well known. Such devices generally comprise a body or housing within which a medicament carrier is located. Known inhalation devices include those in which the medicament is delivered in aerosol form, including the well-known metered dose inhaler (MDI) delivery devices.

It is advantageous to provide the patient with a dose counter for counting the number of doses of medicament dispensed or still remaining. For flexibility, the dose counter should also be suitable for use with various types of medicament dispenser including those suitable for dispensing medicament in aerosol. It is also desirable that any counter be configured to register a count only when medicament is provided to the patient for inhalation, and in particular that opportunities for false counts and/or tampering are minimized. It is further desirable that the count be clearly visible by the patient.

U.S. Patent No. 5,988,496 describes a dose counter comprising a first count wheel and a second count wheel arranged to rotate about a common axis of rotation. The first count wheel includes a drive tongue that is movable between a rest position, in which it does not cooperate with the second count wheel and a drive position, in which it co-operates with the second count wheel to cause it to rotate about the common axis of rotation. The drive tongue is forced into position by action of a cam.

International (PCT) Publication No. WO2005/079727 describes a dose counter for use with a medicament dispenser. The dose counter comprises a first count wheel arranged to rotate about a first axis of rotation, the first count wheel including a set of primary drive teeth arranged annularly thereon for drivable rotation of the first count wheel about the first axis of rotation; and a second count wheel arranged to rotate about the same first axis of rotation. A kick wheel is arranged to rotate about a second axis of rotation offset from the first axis of rotation and provides for intermittent motion of the second count wheel.

U.S. Patent No. 8,596,495 describes a dose counter for counting the number of doses of fluid or powder that have been dispensed or that remain to be dispensed from a fluid dispenser device, said counter including a first rotary counter element forming a units wheel, and a second rotary counter element forming a tens wheel, said first and second counter elements co-operating with each other to define and to display, in a viewing window, said number of doses, said first counter element co-operating with an actuator member that is adapted to cause said first counter element to turn each time said actuator member is actuated, said counter being characterized in that it includes a base body that incorporates a pivot pin for said first and second counter elements and an opening, said counter possibly being pre- assembled in said base body so as to form a pre-assembled counter unit.

U.S. Patent No. 8,245,906 discloses a dose counter for use with a medicament dispenser, said dose counter comprising a ratchet; a first count wheel arranged to rotate about a first axis of rotation, said first count wheel including one or more ratchet drive receipt elements arranged thereon for receipt of drive from said ratchet to rotate the first count wheel about said first axis of rotation; a second count wheel arranged to rotate about the first axis of rotation, said second count wheel including a set of teeth arranged annularly thereon; and a kick wheel arranged to rotate about a second axis of rotation offset from the first axis of rotation, said kick wheel including a set of kick teeth arranged annularly thereon and in meshed relationship with the set of teeth of the second count wheel such that rotary motion of the kick wheel results in rotary motion of the second count wheel, wherein said first count wheel further includes at least one fixed index tooth arranged for intermittent meshing with the kick teeth of the kick wheel such that rotary motion of the kick wheel results from rotary motion of the first count wheel only when said intermittent meshing occurs.

International (PCT) Publication No. WO 2012150427 discloses a dose counter comprising a rotary counting element, or driven wheel, and an actuator, the actuator being movable relative to the rotary counting element from a first position to a second position and comprising a shaped part which engages with a complementary feature of the rotary counting element when the actuator is in said first position to resist rotation of the rotary counter element; characterized in that the shaped part of the actuator is moved out of engagement with the rotary counting element by movement of the actuator towards said second position.

The Applicants have now devised a dose counter that meets some or all of the above criteria. In embodiments, the dose counter may be provided to the medicament dispenser as a separable unit. The dose counter now provided has the advantage that it may be expressed in relatively compact forms and in particular, may be accommodated in a housing that is relatively thin (i.e. one that extends upwards in the direction of the axis defined by the counter wheels to only a minor extent). The counter herein may also be arranged to count over a relatively large count range (e.g. at least 100 counts).

SUMMARY OF THE INVENTION:

According to one aspect of the present invention, there is provided a dose counter for counting the number of doses of a medicament that have been dispensed or that remain to be dispensed from a medicament dispenser device, said counter comprising a cylindrical housing, a trigger member, a ratchet member and a counter member constructed and arranged to undergo a predetermined counting movement each time a dose is dispensed.

According to another aspect of the present invention, there is provided a dose counter comprising a cylindrical housing, a trigger member, a ratchet member and a counter member, wherein the firing of the valve causes downward movement of the trigger member relative to the counter member from a first position to a second position.

According to another aspect of the present invention, the trigger member constructed and arranged to undergo reciprocal movement coordinated with the reciprocal movement between the actuation means and the container, said reciprocal movement comprising an outward stroke and a return stroke. The trigger member, which is arranged to undergo reciprocal movement coordinated with the reciprocal movement between the actuator (e.g. valve) and the container, may be (directly or indirectly) secured to the valve ferrule and/or container and/or the valve stem of a valve depending on the particular reciprocal actuation means and/or inhaler being used. For example in the case of a conventional press-and-breath- inhaler, in which the container is typically positioned vertically with the valve stem oriented downwards and located in a nozzle block and the inhaler is actuated by moving the container downwardly, the trigger may be secured to the ferrule and/or container, so that the trigger moves therewith when the container is depressed to fire the valve and released to return to its rest position under the influence of the valve spring.

According to another aspect of the present invention, there is provided a counter member comprising a cylindrical teeth for interaction with the ratchet member which comprises at least one edged surface which is engaged by the ratchet member during the return stroke of the trigger member causing the counter member to undergo further counting motion to complete said predetermined counting movement.

The dose counter herein further comprises a ratchet member. The ratchet member may be a ratchet wheel which is suitably arranged for rotation about an axis, which is preferably common with the anti-clockwise axis of rotation about which the counter member rotates. Suitably, the ratchet is itself provided with one or more drive receipt elements for receipt of drive that results in movement (e.g. rotation) of the ratchet. Such drive receipt elements can take any form including one or more teeth, protrusions, and/or indents. Drive of the ratchet may be provided by a trigger member provided to the medicament dispenser and movable in response to user action (e.g. manual), which action typically relates to the dispensing action thereof. Suitably, the trigger member is adapted in use to couple with an operating mechanism of a medicament dispenser whereby actuation of the operating mechanism is transmitted to the dose counter.

The counter member includes a counting wheel arranged to rotate about an anti-clockwise axis of rotation. The counting wheel may for example, take the form of a disc or a ring.

The counting wheel includes one or more ratchet member receipt elements arranged (e.g. in spaced fashion) thereon for receipt of drive from said ratchet to rotate the counting wheel about said anti-clockwise axis of rotation. The ratchet member receipt elements can take any suitable form, including one or more teeth and/or indents.

Suitably, the ratchet member receipt elements are arranged annularly, such as about an inner or outer circumferential wall of the counting wheel. Preferably the counting wheel takes the form of a ring that is sized and shaped for disposed receipt of the ratchet member.

The dose counter further has a cylindrical housing. Suitably, the cylindrical housing acts to house the canister, where in canister will be in touch with the trigger member of the dose counter. The firing of the valve causes downward movement of trigger member in touch with the canister housed in cylindrical housing relative to the counter member from a first position to a second position.

The dose counter suitably includes a viewing window through which the count may be viewed. In preferred embodiments, the counter member of the dose counter is in the form of a ring. The ring may be open or closed, but typically it is closed. In the following it is understood that under the term counter member, a counter ring is preferred. The counter member is typically mounted for rotation within housing and has markings e.g. integers or color-coded markings, on the cylindrical side surface which may be viewed through ,, a window in the housing to determine the count. In the direction of advancing count on the counter member, the aforesaid markings may show a count up and/or a countdown of the number of doses. The counter member comprises a first region for interaction with the trigger member and a second region for interacting with the ratchet member. Each region typically comprises a series of inclined surfaces that defines a series of teeth. In one embodiment of the invention the counter member comprises a first set of teeth for engagement with the trigger and a second set of teeth for engagement with the ratchet member. In a second embodiment of the invention the counter member comprises one set of teeth for engagement by both the trigger and ratchet member.

The dose counter herein is in one aspect, suitable for use with a medicament dispenser of any suitable type and may be provided as an insert thereto.

According to another aspect of the present invention, there is provided a medicament dispenser comprises an inhaler body, a canister and a dose counter comprising a trigger member, a cylindrical housing, a ratchet member and a counter member, wherein the firing of the valve causes downward movement of trigger member relative to the counter member from a first position to a second position.

BRIEF DESCRIPTION OF THE DRAWINGS:

To complement the description that is being given and in order to promote a better understanding of the characteristics of the invention in accordance with a practical embodiment of the same and as an integral part of the said description a set of drawings accompany it in which, in an illustrative and non-restrictive way, the following are represented-

Figure 1 shows a trigger member of the invention;

Figure 2 shows a cylindrical housing of the invention;

Figure 3 shows a ratchet member of the invention;

Figure 4 shows a counter member of the invention;

Figure 4.1 shows an arrangement of the components of Figures 1, 3 and 4 of the invention; Figure 5 shows cross-section of actuator body with cylindrical housing of the invention; Figure 6 shows viewing window of the invention;

Figure 7 shows a cross-section of an inhaler device incorporating the dose counter of the invention;

Figure 8 shows an upper view of cylindrical housing of the invention.

Figure 9 shows an arrangement of the trigger member, ratchet member and counter member of the invention;

Figure 10 shows the placement of the trigger member, ratchet member and counter member in the housing of the invention;

Figure 1 1 shows the housing without the trigger member and counter member of the invention;

Figure 12 shows the housing with the viewing window of the invention;

Figure 13 shows the window for counter member to show the no. of doses dispensed of the invention;

Figure 14 shows the symmetrical view of all the components of the invention;

Figure 15 shows the various angles of dose counter in the inhaler of the invention.

DETAILED DESCRIPTION OF THE INVENTION:

The invention will be better understood from the following description of preferred embodiments, with reference to the drawings listed above. Throughout the description terms like 'front' and 'rear' are used for convenience only and are not intended to place any limitation on the orientation of the various components in use.

The embodiment of the invention is shown in Figures 1 to 4 of the accompanying drawings. Figure 1 shows the trigger member component 1 in isolation. The trigger member 1 is a unitary component comprising a rectangular beam 5. A protruded notch 6 for engagement with cylindrical housing 2 which in turn carries an MDI canister (not shown) extends from a front face of the beam 5, at a first end thereof.

A hook 7 is provided at a lower end of the beam 5 for engagement with the teeth of a ratchet member 4. The hook 7 is provided as a generally trapezoidal protrusion extending from one side of the central beam 5 to provide a triangular extension 8 to engage with the teeth of said ratchet member 4, and a trapezoidal part 9 arranged at a smaller angle to the rectangular beam 5.

A further raised area 10 is provided in continuation of protruded notch 6 towards opposite direction and run down towards opposite of rectangular beam 5. The raised area 10 has sides which are parallel to the sides of the beam 5. The rounded notch 1 1 at the end of raised area 10 provides some further rigidity to the part of the central beam 5 between the protrusion 6 and the lower end of trigger member 1.

Figure 2 shows the cylindrical housing 2 of the invention. The cylindrical housing 2 sits into the actuator body near the mouth piece. There are two triangular hooks 12 and 13 of cylindrical housing 2, which runs parallel downwards to the sliding notches 15 & 16. The sliding notches slide through the sliding frames 19 & 20 of actuator body 18 (as shown in Figure 5) for permanent fitting of cylindrical housing 2. The triangular hooks sit permanently near the mouthpiece and prevent the accidental removal of canister as well as the dose counter. If somebody try to remove the said dose counter forcefully, the triangular hooks 12 & 13 may deformed and prevent the accident by non-functioning of the metered dose inhaler.

A rectangular notch 14 of cylindrical housing 2 fits into the protruded area 21 of actuator body 18 to supports for the fixture or to prevent the further unwanted movement of the cylindrical housing 2. There are two pegs 17 and 22 (as shown in Figure 8) inside the cylindrical housing. The two pegs 17 and 22 are placed directly opposite to each other. The pegs 17 and 22 provides the holding to the ferrule of the canister to prevent it coming out after the trigger member 1 push it to fire the valve and released to return to its rest position under the influence of the valve spring.

Figure 3 shows the ratchet member 3 of the invention. The outer circumference of the ratchet member 3 is provided with a ring of toothed part 23 each having a triangular edge 24 which the triangular extension 8 of the hook 7 of the trigger member 1 will engage in use, and a straight edge with a narrow angle can be used. The toothed part 23 comprises at least 10 teeth.

A rounded part 25 extended above the toothed part 23 of the ratchet member 3 and is provided with a single triangular edge 26 which, in use, will engage with part of a Counter member 4 (Figure 4). The opposite face of the ratchet member is flat. Although only one triangular edge 26 is shown, it is possible to provide further drive teeth if required.

Figure 4 shows a counter member 4 of the invention. The counter member 4 is in the form of a generally flat circular ring and has numbers 27 indicative of the number of doses remaining in an MDI canister provided on a face.

Figure 4.1 further shows how the components of Figures 1, 3 & 4 engage during use to form a dose counter mechanism. The opposite side 28 of the counter member 4 is also shown in figure 4.1, but comprises a number of features to be engaged by the triangular edge 26 of the ratchet member 3 and by the rounded notch 11 of the raised area 10 on the trigger member 1. A number of small cylindrical teeth 29 can be seen. The cylindrical teeth 29 are located at a common radius, approximately half way between the inside and outside diameters of the counter member 27, and are provided at least 14 numbers of cylindrical teeth.

Radially outside the cylindrical teeth 29, a further protrusion 30 is provided. The further protrusion 30 is provided as a narrow wall extending around the entire circumference of the counter member 4.

The further protrusion 30 is shaped to form a partial loop around each of the cylindrical teeth 29, such that a number of troughs 31 are formed in the wall. Each trough 31 is sized and shaped to receive the rounded notch 11 of the raised area 10 on the trigger member 1.

As such, there is no link between the ratchet member 3 and the counter member 4 because the ratchet member would be free to rotate in any location of the rounded notch 11 of the raised area 10 on the trigger member 1 within a trough 31 on the counter member 4.

Further, the dose counter has housing. Suitably, the housing acts to house some or all of the other elements of the dose counter. The housing suitably includes a viewing window 32 through which the count may be viewed. Figure 4.1 shows the dose counter mechanism of the first embodiment in a neutral position, i.e. between doses. The ratchet member 3 of the dose counter is almost entirely obscured from view, but is not in engagement with any part of the opposite side 28 of the counter member 4. As such, there is no link between the ratchet member 3 and the opposite side 28 of the counter member 4 as shown in Figure 4.1 , and the ratchet member would be free to rotate.

Further, another Figure 9 (in line with figure 4.1) shows how the components of Figures 1, 3 & 4 engage during use to form a dose counter mechanism. The view of Figure 9 shows the opposite face of the counter member 4 which was not visible in Figure 4. A number of small cylindrical teeth 29 can be seen standing proud of the face of the counter member 4. The cylindrical teeth 29 are located at a common radius, approximately half way between the inside and outside diameters of the counter member 4, and are provided around the majority of its circumference.

During the delivering of dose, pressure applied to an MDI canister will apply a force to the protruded notch 6 in a downward direction. This will cause an upward movement of the trigger member 1 such that the rounded notch 11 of the raised area 10 on the trigger member 1 will move out of the trough 31 allowing the ratchet member to rotate. Since the hook 7 of the trigger member 1 is engaged with one of the toothed part 23 of the ratchet membe 3, the ratchet member 3 will rotate in an anti-clockwise direction as a result of the downward movement of the trigger member 1. However, this anticlockwise movement of the ratchet member 3 will not advance the counter member 4 because the triangular edge 26 will be rotated away from engagement with the left side of the cylindrical teeth 29 nearest to it.

Continuous actuations will lead to continued rotation of the triangular edge 26 away from engagement with the cylindrical teeth 29 and into the space within the inner circumference of the counter member 4 until the ratchet member 3 is rotated round far enough that the triangular edge 26 comes into contact with the right side of the first of the cylindrical teeth 29. At this point, the next actuation of the inhaler will cause further rotation of the ratchet member 3 and the triangular edge 26, which will now be engaged with the cylindrical teeth 29 of the driven wheel will cause the counter member 4 to advance one step. The movement of the counter member 4 and will then allow the triangular edge 26 to move past the cylindrical teeth 29 such that further actuations of the inhaler device will not cause any movement of the counter member 4 until another full rotation of the drive wheel is completed and the triangular edge 26 engages with the right side of a cylindrical teeth 29 of the counter member 4.

Thus, once a dose has been delivered and the ratchet member 3 has been rotated one step, there is a reverse force urging the trigger member 1 to back towards its starting position. When pressure is released from the MDI canister, the force previously acting on protruded notch 6 is removed, and the trigger member 1 is free to move vertically downward under the influence of the reverse force.

It is important in ensuring a reliable count from the dose counter that the movement of the trigger member 1 back to its starting position does not serve to rotate the ratchet member 3 in an anti-clockwise direction. This could be problematic since the actuator will have to move past the ratchet member 3 in two opposite directions.

The counter member 4 is mounted on a cylindrical rod which is provided as a part circular wall engaging the inner surface of the counter member 4 and having an open part to accommodate the trigger member 1 and ratchet member 3.

The advantage of trigger member 1 as described allows for the linear movement of an MDI canister to be a translated into rotational movement of a dose counter in a simple and reliable way without deforming the shape of trigger member 1 for continuous smooth working of dose counter.

Further, the rounded notch 11 of the raised area 10 on the trigger member 1 with each of the trough 31 of the further protrusion 30 of the counter member 4 prevents free rotation of the counter member 4 between actuations. This avoids the danger of accidental movement of the counter when the device is not in use.

Figure 10 shows the components 1, 3 & 4 of Figure 4.1 arranged in a housing 39. In comparison with Figure 4.1, the opposite side of the arrangement of components 1, 3 & 4 is visible. This means that the ratchet member 3 as viewed in Figure 10 will be rotated in a clockwise direction when the trigger member 1 is moved vertically upwards. The protruded notch 6 of the trigger member fitted in a channel 40 in the housing 39 for engagement with an MDI canister. The channel 40 restricts lateral movement of the rectangular beam 5, but it is free to move vertically upwards from the position shown.

The ratchet member 3 is mounted for rotation about a boss extending from an internal surface of the housing 39. A simple ratchet mechanism is provided by a thin rod of material extending from the housing at a slight angle to the internal surface such that its free end is proud of the rear surface. The free end of the rod 41 is shown engaging with the edge of one of the toothed part 23 on the ratchet member 3. The angle of the rod 41 means that when the counter member 4 is rotating in a clockwise direction. However, rotation of the ratchet member 3 in an anti-clockwise direction is resisted by the free end of the rod 41 abutting with the edge of each toothed part 23.

Figure 1 1 shows the internal surface of housing 39. It shows the show a ridge members 41 to provide on which the counter member 4 is to be mounted. There is a stationary boss (not visible) on which the ratchet member 3 is to be mounted and that may be toothed or plane rounded to engage the internal side of the ratchet member 3 and resist rotation of the counter member 4 in one direction in a similar way to the engagement of the rod 41 and the toothed part 23. Further, there are 5 bosses in the housing 39 named as boss 42, the boss 42 provides the way to attach the outer cover 37 (Figure 13) to cover and only provide the view for number of doses dispensed or delivered by MDI canister. Also, Figure 12 the internal side of outer cover 37 along with the viewing window 32 shown in Figure 6. The trigger member 1, ratchet member 3 and counter member 4 fits below the viewing window 32 and then the outer cover 37 fits over the housing 39 to cover the same.

Figure 7 shows how a dose counter is incorporated into an inhaler device 33. Although Figure 7 shows the counter of the embodiments could be integrated into an inhaler body in exactly the same way, either when manufacturing the inhaler bodies or through modification of existing inhaler devices. Preferably, the housing is formed integrally with an inhaler body when the inhaler body is manufactured.

An MDI canister 34 is shown within the inhaler body 35 with its valve stem 36 retrained in position such that a dose will be displaced when a force is applied to the canister 34. The dose counter mechanism is shown built into the inhaler body 35, and an outer cover 37 is provided to conceal the individual components of dose counter i.e. trigger member 1, ratchet member 3, counter member 4 and viewing window 32 from view and to keep dirt out of the mechanism. A window 38 is provided in the outer cover to show a part of the counter member 4 corresponding to the current count of doses remaining in the MDI canister.

As shown in Figure 7, the dose counter is inverted from the position shown in the previous figures. However, the orientation of the dose counter of the present invention has no bearing on its operation.

Figure 14 provides all the parts of dose counter of present invention in order to provide the symmetric view of each part in the dose counter. Figure 15 provides the view of various angles of dose counter with inhaler and canister.

The dose counter may be integrated into, or otherwise provided in combination with, a metered dose inhaler.

In an embodiment, a medicament dispenser comprises an inhaler body, a canister and a dose counter comprising a trigger member, a cylindrical housing, a ratchet member and a counter member, wherein the firing of the valve causes downward movement of trigger member relative to the counter member from a first position to a second position.

In an embodiment, dose counter was described with reference to its use with a conventional press-and-breathe inhaler. However, it will be readily appreciated that the dose counter may be adapted for use with other devices having a reciprocal actuation means, such as dry powder inhalers, pump spray devices, and other liquid spray devices.

The embodiments are intended to be illustrative only, and are not intended to in any way to restrict the scope of the present invention.

The present invention is not limited to the specific embodiment described above. Alternative arrangements and suitable materials will be apparent to a reader skilled in the art.

It will be readily apparent to one skilled in the art that varying substitutions and modifications may be made to the invention disclosed herein without departing from the spirit of the invention. Thus, it should be understood that although the present invention has been specifically disclosed by the preferred embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and such modifications and variations are considered to be falling within the scope of the invention.

It is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of "including," "comprising," or "having" and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items.

It must be noted that, as used in this specification and the appended claims, the singular forms "a," "an" and "the" include plural references unless the context clearly dictates otherwise. Thus, for example, reference to "a ridge" includes a single ridge as well as two or more ridges.

Claims

We claim:

1. A dose counter for counting the number of doses of a medicament that have been dispensed or that remain to be dispensed from a medicament dispenser device, wherein the counter comprises a trigger member (1), a cylindrical housing (2), a ratchet member (3), and a counter member (4) constructed and arranged to undergo a predetermined counting movement each time a dose is dispensed.

The dose counter of claim 1, wherein the trigger member (1) is constructed and arranged to undergo a reciprocal movement coordinated with the reciprocal movement between the actuation means and the container, said reciprocal movement comprising an outward stroke and a return stroke.

The dose counter of claim 2, wherein the trigger member (1) is a unitary component comprising a rectangular beam (5), a protruded notch (6) for engagement with a cylindrical housing 2, which in turn carries an Metered dose inhaler canister and a hook (7) at a lower end of the beam (5) for engagement wi th the teeth of a ratchet member (3 ).

The dose counter of claim 1, wherein the cylindrical housing (2) acts to house the canister, wherein firing of the valve causes a downward movement of the trigger member (1) in touch with the canister housed in the cylindrical housing (2) relative to the counter member (4) from a first position to a second position.

The dose counter of claim 4, wherein the cylindrical housing (2) comprises two triangular hooks (12) and (13), which runs parallel downwards the sliding notches (15) & (16), which slide through the sliding frames (19) & (20) of actuator body (18) for permanent fitting of the cylindrical housing (2).

The dose counter of claim 1, wherein the ratchet member (3) is a ratchet wheel which is arranged for rotation about an axis, which is common with the anti-clockwise axis of rotation about which the counter member (4) rotates.

7. The dose counter of claim 6, wherein the ratchet member (3) comprises a ring of toothed part (23) with a triangular edge (24) which is engaged with the triangular extension (8) of the hook (7) of the trigger member (1) in use, and a rounded part (25) extended above the toothed part (23) is provided with a single triangular edge (26) which will engage with part of a Counter member (4) in use.

8. The dose counter of claim 7, wherein the toothed part (23) comprises at least 10 teeth.

9. The dose counter of claim 1, wherein the counter member (4) comprises a cylindrical teeth (29) for interaction with the ratchet member (3) which comprises at least one edged surface (26) which is engaged by the ratchet member (3) during the return stroke of the trigger member (1) causing the counter member (4) to undergo further counting motion to complete said predetermined counting movement.

10. The dose counter of claim 1, which comprises a housing (39) to accommodate the trigger member (1), counter member (4), and the ratchet member (3).

11. A medicament dispenser comprising an inhaler body, a canister and a dose counter comprising a trigger member (1), a cylindrical housing (2), a ratchet member (3), and a counter member (4), wherein the firing of the valve causes a downward movement of the trigger member (1) relative to the counter member from a first position to a second position.

12. The medicament dispenser of claim 11, wherein the canister of the inhaler contains a medicinal aerosol formulation.