DOSE INHALER WITH A DOSE COUNTER
TECHNICAL FIELD
The invention pertains to a counting mechanism for counting the number of doses delivered from a dose inhaler.
BACKGROUND:
It is common to use dose inhalers to administer medicaments into the oral cavity or nasally. A number of dose inhalers designed to release a predetermined dose when activated are available for the purpose. In the past, the usual way to transfer a medicament from an inhaler to a user was by means of a pressurised container. However, it has become increasingly more common to use breath activated inhalers where the dose transfer is activated and effected by the user's inhalation.
Dose inhalers containing multiple doses and which are intended for repeated use are generally equipped with means for counting the number of doses delivered and/or for indicating the number of doses remaining in the dose container. By providing the inhaler with a counting mechanism indicating the number of doses remaining in the dose container, it is possible to monitor the consumption of the medicament and avoid premature discarding of a container that has not been completely emptied.
One example of an existing counting mechanism is disclosed in the Swedish patent No. 515858 C2. The counting mechanism is arranged on a spray dose inhaler and comprises a lid, a counting wheel and a control wheel, all having generally circular shape and being concentrically stacked on each other. The counting mechanism is arranged to be rotated a predetermined distance when activating the delivery of a dose so that a dose step is counted and the remaining number of doses indicated each time a dose is delivered from the spray dose inhaler.
Another counting mechanism is disclosed in Swedish patent application SE 0301039-4. When using a dose inhaler provided with the counting mechanism, a dose is delivered from a dose container when the dose container is moved in an inhaler body. The counting mechanism comprises a rotatable gear mechanism and a pointer unit arranged to move in a circular path between different positions on a circular indicator wheel. When moving the container in the inhaler body in order to release a dose, the movement simultaneously results in a force acting on the gear mechanism and thereby causing the pointer unit to move a predetermined distance along the circular path.
The previously known counting mechanisms are relatively complicated constructions consisting of several movable parts. Moreover, they are voluminous and make the dose inhalers unnecessarily large and cumbersome to use or carry along for instance in a handbag or a pocket.
Accordingly, although a number of counting mechanisms for dose inhalers have previously been made available, a need for a further improved counting mechanism having a reliable function and a handy and less bulky construction still exists.
There is also a need for a breath activated dose inhaler having an improved counting mechanism.
With the expression "delivery action" is meant the movement of a dose container in a delivery device that triggers the transfer of a dose from the container and out through the delivery device. Hence, the returning movement of the dose container after the dose has been delivered and the dose container returns to its neutral in-rest position is not considered to be part of the delivery action.
When a dose inhaler is used, a hollow mouth piece on the dose inhaler is inserted into the mouth of the user and a container that is mounted in an upper part of the dose inhaler is pressed down into the dose inhaler. The
movement of the dose container activates a delivery mechanism in the inhaler body and results in the release of a dose into the user's oral cavity.
DISCLOSURE OF THE INVENTION
The invention offers a dose inhaler having a counting mechanism with a simple and reliable construction. The counting mechanism can be used with different types of dose inhalers such as pressurised inhalers and breath activated inhalers.
The dose inhaler in accordance with the invention is primarily distinguished in that the counting mechanism comprises a cassette containing a rotatable feed wheel and an indicator strip arranged to be fed by rotation of the feed wheel, the feed wheel and the indicator strip comprising cooperating engagement means, the feed wheel comprising coupling means for coupling to a control means arranged on the dose inhaler, the coupling means comprising means for stepwise rotation of the feed wheel.
The indicator strip is preferably made from a thin material having high tensile strength and is preferably comprises a metal foil band. It has proven to be particularly advantageous to use an aluminium foil band. Alternatively, plastic bands, paper/plastic laminates, plastic/metal laminates, metal/paper laminates, or similar can be used.
The indicator strip is very thin, which means that the counting mechanism only adds to the height of the dose inhaler by one or a few millimetres. The slim construction makes the dose inhaler considerably less clumsy and easier to carry along and use than previously known dose inhalers.
In accordance with one embodiment of the invention, the indicator strip comprises holes arranged with a predetermined spacing in the length direction of the strip and the feeding wheel comprises corresponding protruding engagement means such as spikes or protrusions which are
engagable with the holes in the indicator strip and which are arranged with the same spacing as the holes in the indicator strip.
In order to achieve stability and a uniform tension in the indicator strip, the indicator strip can comprise a row of holes along each side edge of the indicator strip.
The protruding engagement means on the feeding wheel can be arranged on the periphery of the feeding wheel with a spacing dividing the feeding wheel into at least 8 equal parts.
The indicator strip is preferably provided with visually identifiable dose step indications. Such indications may be in the form of numerals indicating the number of remaining doses or, alternatively, the number of delivered doses.
It is also possible to use different types of colour indications to show the amount of medicament in the inhaler. Another possible embodiment is a band having continuously diminishing width, or some other physical design reflecting the level of content in the dose inhaler. Further, it is possible to combine numerical indications with a graphical representation of the level of content in the inhaler.
In order for the user of the inhaler to be able to monitor the dose consumption, the dose inhaler is preferably provided with an indication window through which the dose step indications are visible as the indicator strip is fed past the window.
In order to be mounted on the dose inhaler, the outer casing of the counting mechanism is suitably equipped with means for attachment to the dose container. Such means can be part of a coupling means comprising a corresponding part arranged on the inhaler body. Some examples of useful coupling means are snap locks, slide couplings, or the like. A particularly simple and efficient coupling means is a circular cap that can be slipped over an outer end of a dose container arranged in a dose inhaler. The coupling means is used as an operating means when the dose container is pressed
into the inhaler body when a new dose is being delivered. Alternatively, the counting mechanism can be an integrated part of the dose container
The coupling between the inhaler body and the feed wheel may comprise a control means being attached to the inhaler body and acting on a ratchet arranged on the feed wheel, whereby each delivery action brings the control means to pass over a tooth on the ratchet.
In order to make the counting mechanism easily accessible, it is preferably arranged in an openable cassette. Thereby, the counting mechanism is easy to assemble and it is easy to insert an indicator strip or to change a used indicator strip.
Even if the counting mechanism in accordance with the invention can be used with different types of dose inhalers, it is particularly suitable for use with a breath activated dose inhaler.
The dose inhaler in accordance with the invention preferably comprises a dose container provided with a feed tube. The inhaler body comprises a tubular container part into which the dose container is inserted and a mouth piece in communication with the container part. Further, the inhaler body contains a dose delivery mechanism comprising a spring loaded trigger sail arranged to cooperate with a valve in the feed tube on the dose container for opening and closing the valve and further arranged to be brought from a neutral in-rest-position to an active use position by the delivery action and to be arranged to be activated in the use position by inhalation through the mouth piece and thereby bring the valve to an open position in which a dose in the feed tube can be transferred to a delivery space which is in direct communication with the mouth piece.
It is also advantageous if the trigger sail acts as a means to indicate whether the dose inhaler is in the active position or in the neutral position. This can be achieved by making the trigger sail visible in the active position through an inspection window arranged in the inhaler body. In order to make it easy to
immediately determine whether the trigger sail is present in the inspection window, it is preferred that at least the visible part of the trigger sail has a colour differing from that of the inhaler body.
DESCRIPTION OF FIGURES:
The invention will in the following be described with reference to the embodiments shown in the appended drawings.
Figure 1 shows a counting mechanism in accordance with the invention and mounted in an outer covering or cassette;
Figure 2 shows a feed wheel in the counting mechanism in
Fig. 1 ;
Figure 3 shows an indicator strip in the counting mechanism in Fig. 1 ;
Figure 4 shows a cassette for the counting mechanism in Fig. 1 ;
Figure 5 shows a lid for the cassette in Fig. 4;
Figure 6 shows the counting mechanism in Fig. 1 mounted on a dose container;
Figure 7 shows an inhaler body for a dose inhaler in accordance with the invention;
Figure 8 shows an assempled dose inhaler with a counting mechanism and a dose container;
Figure 9 shows an assembled dose inhaler with the inhaler body partially removed and the delivery mechanism visible in the use position;
Figure 10 shows a detail view of the delivery mechanism in the active position;
Figure 11 shows an assembled dose inhaler with the inhaler body partially removed and the delivery mechanism visible in the delivery position;
Figure 12 shows a detail of the delivery mechanism in the delivery position;
Figure 13 shows a partially assembled dose counter according to a second embodiment of the invention;
Figure 14 shows the partially assembled dose counter in Fig.
13 with an indicator strip;
Figure 15 shows a completely assembled dose counter according to the second embodiment of the invention;
Figure 16 shows the dose counter in Fig. 15 mounted on a dose container;
Figure 17 shows a second embodiment of a dose inhaler in a neutral position;
Figure 18 shows the dose inhaler in Fig. 17 in an activated position;
Figure 19 shows the dose inhaler in Figs. 17 and 18 at the beginning of an inhalation; and
Figure 20 shows the dose inhaler in Figs. 17-19 after a dose has been released.
DESCRIPTION OF EMBODIMENTS:
Fig. 1 shows a dose counter with a counting mechanism for a dose inhaler. The dose counter 1 comprises a feed wheel 2 and a roll of indicator strip 3, arranged in an outer covering or cassette 4. The cassette 4 is openable, whereby the feed wheel 2 and the indicator strip 3 can be readily mounted in the cassette 4. Fig. 1 shows the cassette 4 as it appears when it is opened. When the cassette 4 is mounted on a dose inhaler, it is suitably closed by a lid 5 such as shown in Fig. 5. The cassette is closed by snapping the lid over the opening 6 in the cassette 4. The cassette is further equipped with an annular coupling part 7 designed to be slid over an end portion 8 of a cylindrical dose container 9, as shown in Fig. 6.
The main components of the counting mechanism 1 are the feed wheel 2 and the indicator strip 3, which is arranged to cooperate with the feed wheel 2. As best shown in Fig. 2, the feed wheel 2 has a cylindrical shape and is provided with a row of protruding engagement means 10 along each edge of the cylinder. The engagement means 10 are arranged equidistantly in parallel rows on the feed wheel 2 and with the spacing between the engagement means 10 in each row being synchronised such that two engagement means 10 are positioned on the same axial line on the surface of the feed wheel 2. Further, the feed wheel has a ratchet 11 arranged to cooperate with a control means for turning the feed wheel a distance corresponding to one dose step.
The indicator strip is best shown in Fig. 3 and is provided with holes 12 along both side edges. The holes 12 have the same general shape as the cross- section of the protruding engagement means 10 on the feed wheel 2 and are arranged on the indicator strip 3 with the same spacing as the engagement means 10. When the feed wheel 2 and the indicator strip 3 are mounted in the cassette 4, the protruding engagement means 10 on the feed wheel 2 are engaged in the holes 12 on the indicator strip 3. Thereby the indicator strip 3
can be fed by rotation of the feed wheel 2, in the same manner a film strip is fed in a camera.
As is shown in Fig. 3, the indicator strip 3 is in the form of a roll 13 that is rotatably mounted in the cassette 4 of the counting mechanism 1 , as shown in Figs. 1 and 6. The indicator strip 3 is provided with dose step indications 14. In the embodiment shown in the Figs., the dose step indications 14 are numerals showing the remaining number of doses in the dose inhaler. As the indicator strip 3 is moved forward by rotation of the feed wheel 2 when an inhalation dose is delivered a new dose step indication 14 will be advanced to an inspection position. Fig. 6 shows a dose step indication 14 that is visible through an indication window 15. The part of the indicator strip 3 that has been unwound from the roll 13 is passed down into a collection space 16 in the cassette 4 of the counting mechanism. As the dose inhaler is emptied of its contents, and the doses are counted down to zero, the collection space 16 will gradually be filled with the used indicator strip 3. When no more doses are to be delivered from the dose inhaler, the cassette 4 can be opened by removing the lid 5 and the unwound indicator strip 3 can be removed and discarded. The counting mechanism can then be used again with a fresh dose container if the discarded indicator strip 3 is replaced with a new indicator strip.
The cassette 4 of the counting mechanism 1 and the feed wheel 2 are preferably moulded or injection moulded plastic details. The indicator strip 3 is preferably a flexible metal or plastic foil band. It has proven particularly suitable to use indicator strips made of aluminium or aluminium/plastic laminates.
The specific designs disclosed for the cooperating engagement means (the protruding engagement means 10 and the holes 12) on the feed wheel 2 and the indicator strip 3 are not critical to the invention. Accordingly, instead of the square shapes shown for the engagement means 10,12, it is possible to use holes and protrusions that are circular, rectangular, oval, etc. Moreover,
the invention is not limited to the use of two rows of cooperating protrusions/holes. Hence, it is alternatively possible to use one or several rows. The rows can be arranged along straight paths, as shown in the Figs, or can be arranged along one or more paths undulating between the side edges of the feed wheel. Further, the engagement means may be placed in a zig-zag pattern or in any other suitable pattern.
The counting mechanism 1 is mounted in a dose inhaler together with a dose container 9 as shown in Fig. 6. The coupling part 7 of the cassette 4 is attached by snapping it over an end 8 portion of the dose container 9. The dose container 9 and the counting mechanism 1 are thereafter inserted into an inhaler body 17 of the kind shown in Fig. 7, whereafter the assembled dose inhaler 18 has the appearance shown in Fig. 8.
The main components of the inhaler body 17 is a tubular container part 19 and a mouth piece 20 protruding from the container part 19 and being in communication with the inside of the container part 19. The dose container 9 is movably arranged in the container part 19 such that the dose container can be pressed further into the inhaler body 17 when compared to the position shown in Fig. 7. The control means 21 that acts on the feed wheel 2 in the counting mechanism when the dose inhaler is being used is best shown in Fig. 7. The control means 21 is in the form of a resilient tongue. When the dose container 9 is pressed into the inhaler body the control means is pressed against a tooth on the ratchet 11 on the feed wheel 2 so that the feed wheel 2 is rotated one step and advances the indicator strip 3 a corresponding distance.
As seen in Fig. 9, the inhaler body 17 contains a dose delivery device 22 comprising a spring loaded trigger sail 23 arranged to cooperate with a valve 25 that is coupled to the feed pipe 24 on the dose container 9 to open and close the valve 25. When the dose container 9 is pressed into the inhaler body 17, the trigger sail 23 is simultaneously moved from a neutral position to an activated position. The user can see that the inhaler is activated for use by
the trigger sail becoming visible trough an inspection window 26 in the inhaler body 17, as is shown in Fig. 9. For this purpose, at least the visible part of the trigger sail 23 preferably has a colour that contrasts with the colour of the inhaler body 17 so that it is easy to establish whether the trigger sail 23 is positioned in front of the inspection window 26 or not. At the same time as the trigger sail 23 is raised to the activated position, the valve 25 is opened so that a dose located in the feed pipe 24 of the dose container 9 can be transferred to a delivery space 27 in the inhaler body 17. The delivery space 27 is in direct communication with the mouth piece 20 on the inhaler body 17.
In the shown embodiment, the valve 25 is a needle valve having a pin 28 that moves in a valve duct 29 to open and close the feed pipe 24 on the dose container 9. The valve 25 and the trigger sail 23 are mounted on a base having a base plate 30 and a hollow circular stem 31 into which the the feed pipe 24 is inserted. When the valve 25 is in the open position, the dose located in the feed pipe 24 can be released to the delivery space 27 trough a spray nozzle 32 arranged in the base stem 31.
The trigger sail 23 is coupled to the base stem 31 by two helical springs 33 and is pivotable around a hinge 34 between the neutral position, the activated position and the delivery position. The spring loaded coupling between the trigger sail 23 and the base ascertains that the dose container 9 automatically is returned to the neutral in-rest position when a new dose has been fed into the delivery space and the user ceases to press down on the dose container.
The function of the dose inhaler 18 and the counting mechanism 1 will now be described in more detail with reference to Figs. 9-12.
When the dose container 9 is pressed into the container part 19 of the inhaler body 17 by a user exerting pressure on the coupling part 7, the following happens:
1. A dose is filled up inside the dose container's 9 feed pipe 24.
2. In the counting mechanism 1 , the control means 21 is pressed against a tooth on the ratchet 11 on the feed wheel 2 so that the feed wheel 2 is rotated a distance corresponding to one dose step. In the shown example, this means that the feed wheel 2 is rotated 1/8 revolution and that a new dose number 14 becomes visible in the indicator window 15.
3. The trigger sail 23 is raised to the activated position and becomes visible through the inspection window 26 to show that the dose inhaler is ready to use.
4. The valve needle 28 is pressed forward into the valve duct 29 and closes the needle valve 25 as is shown in Fig. 10.
5. The helical springs are locked in the activated position by a locking means 51 on the trigger sail 23.
6. It is now possible to use the inhaler by inhaling the loaded dose through the inhaler's mouth piece 20. When the user starts inhaling, a small vacuum is built up in the delivery space due to the delivery space 27 being sealed off from the remaining part of the inhaler body 17. The vacuum causes the trigger sail 23 to move a small distance down into the delivery space 27 as is shown in Figs. 11 and 12. Two arms 35, one on each side of the base stem 31 will then press the valve needle 28 back out of the valve duct 29 so that the needle valve 25 is opened.
7. The dose that is loaded in the feed pipe 24 is released through" the spray nozzle 32 in the base stem 31.
As is seen, for instance in Fig. 10, the arms 35 guiding the needle valve 25 are inserted into a guiding and locking recess 36 in the valve needle holder 37 and control and limit the movements of the trigger sail 23.
Accordingly, the valve 25 is operated by the movements of the trigger sail 23. The spray nozzle 26 can be a conventional spray nozzle. If it is desired to diminish the delivery speed for the released dose cloud, a cavity can be located beneath the valve duct to reduce the pressure in the valve. Some users experience an unpleasant choking sensation when a dose is delivered at high speed. Hence, a reduced pressure may be highly beneficial in order to make dose delivery more comfortable to the user.
In a dose inhaler in accordance with the invention, the time from loading a dose until it is released through the needle valve is very short and equals the time it takes from activating the dose inhaler until the user breathes in through the mouth piece 20.
A second embodiment of a counting mechanism for a dose inhaler is shown in Figs. 13-16.
The counting mechanism according to the second embodiment comprises a dose counter cassette 4 and a feed wheel 2 mounted in the cassette 4 together with an indicator strip 3. The cassette is further equipped with a cap- shaped coupling part 7 designed to be slid over an end portion 8 of a cylindrical dose container 9, as shown in Fig. 16. Further, the feed wheel 2 has a ratchet 11 arranged to cooperate with a control means for turning the feed wheel 2 a distance corresponding to one dose step when the dose container is moved inside a dose inhaler. As in the first embodiment, the control means is preferably a resilient tongue arranged on the inhaler body and pressing against the ratchet 11 so that the feed wheel is rotated when the dose container is moved in the inhaler body. Then number of teeth on the ratchet determines how much the feed wheel is rotated each time the inhaler is used. The ratchet preferably has at least 8 teeth.
The indicator strip is initially in the form of a roll of thin material, as described in connection with the previously described embodiment. The feed wheel 2 has protruding engagement means 10 in the form of axially oriented
elongated ridges placed equidistantly on the surface of the feed wheel 2. The engagement means 10 are arranged to cooperate with corresponding elongated slots 12 arranged in the indicator strip 3. In the shown embodiment, the engagement means 10 and the slots are positioned centrally along a straight path on the feed wheel 2 and the indicator strip 3, respectively. However, it is alternatively possible to arrange the engagement means and the slots in an undulating path, moving between the side edges of the feed wheel and the indicator strip. The cassette 4 is closed by a snap-on lid 5 having a dose indication window 15 through which dose indications 14 on the indicator strip 3 become visible as the indicator strip is unwound when the counting mechanism is operated.
The counting mechanism 1 is operated in the same manner as the previously described mechanism, a dose step being counted every time the dose inhaler is operated.
Fig. 17 shows the counting mechanism 1 in Figs. 13-16 when mounted on a dose inhaler 18 together with a dose container 9. The dose inhaler 18 in Fig. 17 is shown in a neutral, in-rest position, such as it will appear between delivery of doses. The dose inhaler 18 is locked in the neutral position by means of a protective cover 39 serving the dual purpose of protecting the dose inhaler and preventing unintentional dose release.
The coupling part 7 of the counter cassette 4 is attached by being snapped over an end portion 8 of the dose container 9. The dose container 9 and the dose counter 1 are thereafter inserted into an inhaler body 17.
The main components of the inhaler body 17 is a tubular container part 19 and a mouth piece 20 protruding from the container part 19 and being in communication with the inside of the container part 19. The dose container 9 is movably arranged in the container part 19 such that the dose container can be pressed further into the inhaler body 17 when compared to the position shown in Fig. 17. A control means in the form of a resilient tongue (not visible
in Fig. 17) acts on the feed wheel 2 in the counting mechanism when the dose inhaler is being used. The design and operation of the control means is the same as has previously been described with reference to Fig. 7. When the dose container 9 is pressed into the inhaler body 17 the control means is pressed against a tooth on the feed wheel ratchet 11 so that the feed wheel 2 is rotated one step and advances the indicator strip 3 a corresponding distance. When the container 9 returns to its neutral position after a dose has been delivered, the control means snaps back over the next tooth in the ratchet 11 and comes to rest in a position to activate the counting of a new dose the next time the inhaler is used.
The inhaler body 17 contains a dose delivery device 22 comprising a spring loaded trigger sail 23 arranged to cooperate with a valve 25 that is coupled to the feed pipe 24 on the dose container 9 to open and close the valve 25. When the dose container 9 is pressed into the inhaler body 17, the trigger sail 23 is simultaneously moved from a neutral position to an activated position. The movements of the trigger sail 23 are shown in an inspection window 26 in the inhaler body 17. For this purpose, at least the visible part of the trigger sail 23 preferably has a colour that contrasts with the colour of the inhaler body 17 so that it is easy to establish that the trigger sail 23 is positioned in front of the inspection window 26. Moreover, as the trigger sail moves between the neutral position and an activated position, the movement can preferably be detected by a colour change in the visible parts of the trigger sail 23. Accordingly, in the shown embodiment, the part 40 of the trigger sail 23 that is visible through the inspection window 26 when the dose delivery device 22 is in the neutral position has a different colour than the part 41 that is visible when the dose delivery device is activated. Preferably, the first part 40 is green and the second part 41 is red but other colours may of course be used if desired.
In the neutral position shown in Fig. 17, it is impossible to release a dose from the dose inhaler. The protective cover 39 is locked in place over the
mouth piece 20 by means of a catch 42 inserted through an opening 50 in the inhaler body 17. The catch 42 is inserted beneath a locking heel 43 on the dose counter cassette 4 and prohibits downward movement of the counting mechanism 1 and the dose container 9.
When the protective cover 39 is opened, as shown in Fig. 18, it is possible to press down on the dose container and release a dose into a metering chamber 44 in the valve 45 that is a standard part of the dose container. The released dose is subject to a first expansion. In the shown example the dose volume is expanded approximately two times.
In the shown embodiment, the valve 25 is a needle valve having a pin 28 that moves in a valve duct 29 to open and close a delivery duct 46 in the delivery mechanism 22. The valve 25 and the trigger sail 23 are mounted on a base having a base plate 30, a hollow circular stem 31 arranged perpendicularly on the base plate 30 and a delivery duct 46 connecting the valve duct 29 in the stem 31 with the mouth piece 20.
The trigger sail 23 is held in place in the mechanism by being pivotably hinged to the valve needle 28 and by having a lever 47 connected to a plate spring 48 that is attached to the base plate 30. The connection between the lever 47 and the plate spring 48 is such that the lever 47 locks in a recess 49 in the plate spring when the trigger sail 23 is in the positions shown in Figs. 17 and18. The spring loaded coupling between the trigger sail 23 and the base ascertains that the dose container 9 automatically returns to the neutral in-rest position when a new dose has been fed into the delivery space and the user ceases to press down on the dose container.
When the dose container 9 is pressed down, the locking heel 43 on the dose counter cassette moves down and locks into the opening 50 in the inhaler body 17, thereby preventing further downward movement. The counting mechanism is rotated and counts down one dose step. In this position, the
dose that has been filled up in the metering chamber 44 is still prevented from being released by the needle valve 25.
In Fig. 19, inhalation has begun through the mouth piece 20. The suction has caused the trigger sail 23 to move downward a small distance, approximately 7°. This movement causes the lever 47 on the trigger sail 23 to disengage from the recess 49 in the plate spring 48 and releases the plate spring. The pin 28 in the needle valve 25 starts to move down.
In Fig. 20, the needle valve 25 is fully opened. The volume of the metered dose is further expanded. In the shown example the expansion is approximately 1.5 times. As explained above, the expansion of the dose lowers the pressure in the dose cloud and reduces or removes any discomfort that may be experienced by the user of the inhaler when the dose is delivered. The second part 41 of the trigger sail 23 becomes visible through the inspection window 26 to indicate that a dose is released.
After delivery of the dose, the user closes the protective cover 39 over the mouth piece 20 and the dose inhaler returns to the appearance in Fig. 17. When closing the cover 39, the catch 42 on the cover 39 is inserted into the opening 50 and pushes out the locking heel 43 on the dose counter cassette 4 so that the dose counter and the dose container can return to the in-rest position.
It is, of course, possible to use the described counting mechanisms together with other types of dose delivery mechanisms than those disclosed herein.