WO2006062450A1

WO2006062450A1 - Dose indicator for a dose inhaler

Info

Publication number: WO2006062450A1
Application number: PCT/SE2004/001836
Authority: WO
Inventors: Ernst Hörlin
Original assignee: Ernst Hörlins Ingenjösbyra Ab
Priority date: 2004-12-10
Filing date: 2004-12-10
Publication date: 2006-06-15

Abstract

A dose indicator (1) for indicating the amount of doses delivered from a dose inhaler. The dose indicator (1) comprises a housing containing a indicator mechanism in the form of a worm gear, the worm gear comprising a rotating pointer wheel (2) and a gear axis (3) having an external thread (14). The pointer wheel (2) has a first side (7) comprising peripherally arranged dose indications (9) and a second side (8) comprising peripherally arranged teeth (10) and is mounted in the housing (4) with the teeth (10) in engagement with the external thread (14) on the gear axis (3). The housing comprises an indication window (21) and the pointer wheel (2) is mounted in the housing (4) with a part of the dose indications (9) visible through the indication window (21) and with the gear axis (3) rotatably joined to the housing (4).

Description

DOSE INDICATOR FOR A DOSE INHALER

TECHNICAL FIELD

The invention concerns a dose indicator for indicating the amount of doses delivered from and/or remaining in a dose inhaler.

BACKGROUND ART

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. The most common way to transfer a medicament from an inhaler to a user is 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.

When a breath-activated dose inhaler is used, a dose 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 releases a dose for delivery to a user. Delivery of the dose into the oral cavity of the user takes place through a hollow mouth piece on the dose inhaler when the user inhales though the mouth piece.

Dose inhalers containing multiple doses and which are intended for repeated use are generally equipped with some means for indicating or 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 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 not yet completely emptied container.

One example of a 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/indicating 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 dose indicating or counting mechanisms for dose inhalers have previously been made available, a need for a further improved counting mechanism having a reliable function and a simple and less bulky construction still exists.

Particularly, there is a need for an improved dose indicator for a breath activated dose inhaler. DISCLOSURE OF INVENTION

The invention offers a dose indicator having a simple and reliable construction. The dose indicator device is preferably used with breath activated dose inhalers such as those disclosed in co-pending patent applications Nos:.

The delivery device in accordance with the invention is primarily distinguished in that said dose indicator comprises a housing containing a indicator mechanism in the form of a worm gear, the worm gear comprising a rotating pointer wheel and a gear axis having an external thread, the pointer wheel having a first side comprising peripherally arranged dose indications and a second side comprising peripherally arranged teeth and being mounted in the housing with the teeth in engagement with the external thread on the gear axis, the housing comprising an indication window and the pointer wheel being mounted in the housing with a part of the dose indications visible through the indication window and with the gear axis being rotatably joined to the housing.

The gear axis preferably comprises coupling means for movable coupling of the gear axis to a part of a dose inhaler and for incremental rotation of the gear axis. The coupling means connects the indicator mechanism to the dose inhaler so that when the user operates the inhaler, the indicator mechanism is simultaneously operated to indicate that a dose has been delivered from the inhaler.

The coupling means may comprise a toothed ratchet. In accordance with one embodiment a toothed ratchet is arranged at each end of the gear axis.

The teeth on the pointer wheel may be arranged equidistantly in a row along a first part of the periphery of the second side of the pointer wheel. The distance between the teeth is adapted to the width of the external thread on the gear axis. The number of teeth in the row of teeth along the periphery of the pointer wheel is chosen so that the pointer wheel is rotated a suitable distance with each delivered dose. Preferably, there is a gap between the teeth at each end of the row of teeth, the gap having a length exceeding the distance between the equidistantly arranged teeth. The purpose of the gap is to provide a position on the pointer wheel in which the gear mechanism is non-operational. This is achieved by making the gap sufficiently long so that the gear axis becomes disengaged from the teeth on the pointer wheel, when the external thread on the gear axis coincides with the gap in the row of teeth on the pointer wheel.

The pointer wheel may also comprise a stop-knob protruding from the first side or the second side of the pointer wheel between the row of teeth and the centre of the pointer wheel and being arranged diametrically opposite to the gap. The stop-knob is intended to stop against a stop-means arranged on the housing in order to define an end position for the operation of the indicator mechanism. Accordingly, as the indicator mechanism reaches the end position, it will stop working. The presence of the gap in the row of teeth on the pointer wheel ascertains that the dose inhaler on which the indicator is mounted will still be operational.

In order to attach the dose indicator to a dose container in a dose inhaler, the housing may comprise a cap or ring-shaped connection part that is shaped to fit over the top of a dose container for a dose inhaler. When mounting the indicator on the inhaler, the connection part is slid over the top of the dose container to form a connected unit. When the user operates the dose inhaler, the dose indicator together with the dose container is manually pushed down into an inhaler body. For this purpose, the cap or ring-shaped connection part preferably has an upper surface with a shallow bowl-shape so as to conform to the user's fingertip.

The housing may be formed with a front wall and two side walls. The front wall of the housing may comprise a circular through-going hole or a recess extending only partly through the wall, from the inside of the housing. The pointer wheel preferably has a corresponding central circular opening, the pointer wheel being mounted on a circular axis that is inserted through the central opening in the pointer wheel and into the hole or recess in the housing wall. Alternatively, the circular axis may be fixed at the centre of the pointer wheel and the pointer wheel is mounted in the housing with the circular axis inserted in the hole or recess in the housing wall. Obviously, a further alternative is to have a circular axis fixed on the housing wall and inserted into a central hole on the pointer wheel.

When the circular axis is a component separate from the housing wall and the pointer wheel, it may be arranged at the end of a stop bar, which extends from a lower rim of the housing's cap or ring-shaped connection part to the hole or recess in the front wall. The stop bar serves the further purpose of providing an end position for the indicator mechanism by hindering further movement of the pointer wheel when the pointer wheel has reached a position in which the stop knob on the pointer wheel contacts the stop bar. The stop knob is preferably placed on the pointer wheel opposite a gap between the teeth on the pointer wheel, as previously described.

If the width of the gap is made to correspond to the length of the portion of the gear axis occupied by the outer thread, the pointer wheel and the gear axis will become disengaged and the indicator mechanism will stop its operation when the pointer wheel reaches the end position. However, the dose inhaler will still be operational due to the presence of the gap in the row of teeth on the pointer wheel. Hence, the gap allows the gear axis to be rotated without simultaneous rotation of the pointer wheel.

Further, the housing may comprise means for enabling and disabling a delivery mechanism on a dose inhaler.

The dose indicator according to the invention has a simple and reliable construction and consists of only three main parts. The parts are preferably made from plastic material, but metal parts are also conceivable. BRIEF DESCRIPTION OF DRAWINGS

The invention will in the following be described with reference to the embodiments shown in the appended drawings.

Figure 1 shows a dose indicator for a breath activated dose inhaler, mounted in a housing;

Figure 2 shows the dose indicator in Fig. 1 from the inside;

Figure 3 shows a pointer wheel in the dose indicator in Fig.

1 , as seen from a first side;

Figure 4 shows the pointer wheel in Fig. 3, as seen from a second side;

Figure 5 shows a gear axis for the dose indicator in Fig. 1 ;

EMBODIMENTS OF THE INVENTION

The dose indicator 1 shown in Figs. 1 and 2 comprises three main parts: a pointer wheel 2, a gear axis 3 and an outer housing 4. In the shown embodiment, all parts are moulded plastic details. The pointer wheel 2 and the gear axis 3 are mounted in the housing 4 and form a worm gear, as is best seen in Fig. 2. The gear axis 3 is connected to the housing 4 by a pin 5 at each end of the axis. The pins 5 are inserted into corresponding holes or recesses 6 in the housing 4 so as to allow rotation of the gear axis 3 around the pins 5.

The pointer wheel 2 has a first side 7 that is shown in Fig. 3 and a second side 8 that is shown in Fig. 4. The first side 7 comprises peripherally arranged dose indications 9 in the form of lines and numbers. The second side 8 comprises a row of peripherally arranged teeth 10 along the major part of the pointer wheel's 2 periphery but leaving a gap 11 that is free from teeth 10. Further, a stop-knob 12 protruding from the second side 8 of the pointer wheel 2 is arranged between the row of teeth 10 and the centre of the pointer wheel 2. In addition, the pointer wheel is provided with a central opening 13 for enabling attachment to the housing 4 and rotational movement of the pointer wheel 2.

The second element, the gear axis, is shown in Fig. 5. The gear axis 3 is shaped to conform to the contour of the pointer wheel 2 and has a thinner mid-section 15 and thicker end sections 16 with an external thread 14 arranged in the mid-section. The end sections 16 are provided with toothed ratchets 17 that are intended to be acted on by a coupling means arranged on a dose inhaler. The dose indicator 1 is designed to be attached to a dose container that is moved in and out of an inhaler body in order to feed a new dose to a delivery device in the dose inhaler. The coupling means is preferably a part of the inhaler body and can be the form of a resilient tongue that is in spring-loaded contact with a ratchet 17 on the dose indicator 1. When the dose container is pressed into the inhaler body, the coupling means is pressed against a tooth on the ratchet 17 on the gear axis 3 so that the gear axis 3 is rotated one step and in turn rotates the pointer wheel 2 a corresponding distance.

The housing 4 for the indicator mechanism comprises an upper ring-shaped connection part 18 that is shaped to fit over the top of a dose container for a dose inhaler (not shown in the figures) so that the dose indicator 1 can be attached to the dose container. The connection part 18 forms a cap over the end of the dose container and has a slightly concave upper surface 27 to provide a comfortable grip portion adapted to the shape of a finger tip. The upper surface 27 of the connection part 18 serves as a push-button for pushing the dose indicator and a connected dose container into a dose inhaler. However, the connection part 18 may comprise only the annular rim portion 28 without the upper surface. In such an embodiment, the user will press down directly on the dose container when operating the dose inhaler. The housing 4 has a front wall 19 and two side walls 20 but is open at the rear. When the dose indicator is mounted on a dose container in a dose inhaler, the front wall 19 and side walls 20 together with the outside of the dose container form a compartment enclosing the indicator's gear mechanism. An indication window 21 is arranged in an upper part of the housing's front wall 19 and the pointer wheel is mounted in the housing 4 with a part of the dose indications 9 visible through the indication window 21. As the pointer wheel 2 is rotated during operation of the indicator mechanism, the dose indications 9 will be shown successively in the indication window 21.

Further, the housing 4 is provided with a locking means 22, extending from a lower part of the front wall 19 and having a springy portion 23 and an end knob 24. The locking means 22 is optional, but is preferred when using the dose indicator for a breath activated dose inhaler. The locking means 22 is used to lock and unlock the delivery mechanism on a breath activated dose inhaler by inserting and removing the end knob into a locking hole or recess on the dose inhaler.

A hole 25 is provided in the front wall 19, corresponding to the central opening 13 in the pointer wheel 2 in order to enable secure attachment of the pointer wheel 2 in the housing 4.

When mounted in the housing 4, the pointer wheel 2 is arranged with the teeth 10 in engagement with the external thread on the gear axis 3 so as to form a worm gear, as is shown in Fig 2. The pointer wheel is held in place by means of a circular axis 26 arranged at the end of a stop bar 27, which extends from a lower rim of the housing's ring-shaped connection part 18 to the hole 25 in the front wall 19. The circular axis 26 is inserted through the central opening 13 in the pointer wheel 2 and through the hole 25 in the housing wall 19 so that the pointer wheel 2 is held in place between the stop bar 27 and the inside of the front wall 19. As can be seen in Fig. 2, the stop bar 27 also provides an end position for the indicator mechanism by hindering further movement of the pointer wheel 2 when the pointer wheel 2 has reached a position in which the stop knob 12 comes into contact with the stop bar 27. The stop knob 12 is placed on the pointer wheel 2 opposite the gap 11 between the teeth 10 on the pointer wheel 2. The width of the gap 11 corresponds to the length of the portion of the gear axis 3 occupied by the outer thread 14. This implies that when the pointer wheel 2 reaches the end position, the pointer wheel 2 and the gear axis 3 will become disengaged and the indicator mechanism will stop its operation but it will still be possible to use the dose inhaler.

Claims

1. A dose indicator for indicating the amount of doses delivered from a dose inhaler, characterized in that said dose indicator comprises a housing containing a indicator mechanism in the form of a worm gear, said worm gear comprising a rotating pointer wheel (2) and a gear axis (3) having an external thread (14), said pointer wheel (2) having a first side (7) comprising peripherally arranged dose indications (9) and a second side (8) comprising peripherally arranged teeth (10) and being mounted in said housing (4) with said teeth (10) in engagement with said external thread (14) on said gear axis (3), said housing comprising an indication window (21) and said pointer wheel (2) being mounted in said housing (4) with a part of said dose indications (9) visible through said indication window (21) and with said gear axis (3) being rotatably joined to said housing (4).

2. A dose indicator according to claim ^characterized in that said gear axis (3) comprises coupling means (17) for movable coupling of said gear axis (3) to a part of a dose inhaler and for incremental rotation of said gear axis (3).

3. A dose indicator according to claim 2, characterized in that said coupling means (17) comprises a toothed ratchet.

4. A dose indicator according to claim 3, characterized in that said coupling means (17) comprises a toothed ratchet (17) arranged at each end of said gear axis (3).

5. A dose indicator according to any one of claims 1-4, characterized i n that said teeth (10) on said pointer wheel (2) are arranged equidistantly in a row along a first part of said periphery of said second side (8) of said pointer wheel (2) and that a gap (11) is formed between said teeth (10) at each end of said row of teeth (10), said gap (11) having a length exceeding the distance between the equidistantly arranged teeth (11).

6. A dose indicator according to claim 5, characterized in that the length of said gap (11) is at least four times the distance between said equidistantly arranged teeth (11 ).

7. A dose indicator according to claim 5 or 6, characterized in that said pointer wheel (2) comprises a stop-knob (12) protruding from the second side (8) of said pointer wheel (2) between said row of teeth (10) and the centre of the pointer wheel (2) and being arranged diametrically opposite to said gap (11).

8. A dose indicator according to any one of the preceding claims, c h a r a c t e r i z e d i n that said housing (4) comprises a cap or ring-shaped connection part (18) that is shaped to fit over the top of a dose container for a dose inhaler.

9. A dose indicator according to any one of the preceding claims, c h a r a c t e r i z e d in that said housing (4) comprises a front wall (19) and two side walls (20).

10. A dose indicator according to claim 9, characterized in that said front wall (19) of said housing (4) comprises a circular hole or recess (25) and said pointer wheel (2) has a central circular opening (13), said pointer wheel (2) being mounted on a circular axis (26) that is inserted through said central opening (13) in said pointer wheel (2) and through said hole or recess (25) in said housing wall (19).

11. A dose indicator according to claim 10, cha racterized i n that said circular axis (26) is arranged at the end of a stop bar (27), which extends from a lower rim of said housing's (4) ring-shaped connection part (18) to said hole or recess (25) in said front wall 19.

12. A dose indicator according to claim 11, cha racte rized i n that said stop bar (27) is arranged to provide an end position for the indicator mechanism by hindering further movement of said pointer wheel (2) when said pointer wheel (2) has reached a position in which said stop knob (12) on said pointer wheel (2) contacts said stop bar (27).

13. A dose indicator according to claim 12, cha racterized i n that said stop knob (12) is placed on said pointer wheel (2) opposite said gap (11) between said teeth (10) on said pointer wheel (2).

14. A dose indicator according to claim 13, characterized in that the width of said gap (11) corresponds to the length of the portion of the gear axis (3) occupied by the outer thread (14) so that when said pointer wheel (2) reaches said end position, said pointer wheel (2) and said gear axis (3) will become disengaged and said indicator mechanism will stop its operation.

15. A dose indicator according to any one of the preceding claims, c h a r a c terized in that the housing comprises means for enabling and disabling a delivery mechanism on a dose inhaler.