WO1998051359A1

WO1998051359A1 - Powder inhaler with metering device

Info

Publication number: WO1998051359A1
Application number: PCT/NL1998/000271
Authority: WO
Inventors: Erwin Petrus Boes; Johannes Hubertus Jozef Maria Kelders
Original assignee: R + D Injector Ag
Priority date: 1997-05-14
Filing date: 1998-05-14
Publication date: 1998-11-19
Also published as: AU7554698A; NL1006058C2

Abstract

The invention relates to a device for dosed dispensing of a powder-form or granular material, provided with a container for the material having a dispensing opening through which a user can suck up the dosed material, operable dosing means arranged in the vicinity of the dispensing opening and operating means co-acting with the dosing means and movable manually by the user, wherein the dosing means are adapted to dispense a single dose of material at an operating movement of the operating means. The dosing means, which can be rotatable, are herein adapted for continuous transport of material from the container directly to the dispensing opening and are displaceable through a limited stroke by the operating means. The movement of the operating means is thereby bounded. The operating means can be linearly movable, wherein a transmission is then arranged between the operating means and dosing means. This transmission comprises for instance a gear rack connected to the operating means and, co-acting therewith, a toothed wheel connected to the dosing means, wherein one outer end of the gear rack co-acts with loop-shaped guide means.

Description

POWDER INHALER WITH METERING DEVICE

The invention relates to a device for dosed dispensing of a powder-form or granular material, provided with a container for the material having at least one dispensing opening through which a user can suck up the dosed material, operable dosing means arranged in the vicinity of the dispensing opening and operating means co-acting with the dosing means and movable manually by the user, wherein the dosing means are adapted to dispense a single dose of material at an operating movement of the operating means. Such a dosing device is known from US-A-5 437 270.

The known dosing device is intended for dosed dispensing of a powder for inhaling by a user, for instance a prophylactic or a pharmacon. The device is provided with a container in which a powder can be received, with a dispensing opening and a rotatable dosing wheel connecting thereto. The dosing wheel, which takes a conical form, has a number of regularly distributed chambers which are recessed into the cone surface. The dosing wheel is operated by a push-button via a ratchet mechanism with resetting spring.

By rotating the dosing wheel the chambers are guided one by one past the dispensing opening of the container and subsequently displaced to an opening in an inhalation mouthpiece. When placed in register with the dispensing opening the chambers are herein filled in each case with a measured dose of the powder which can be sucked up by the user when the chamber lies in register with the opening in the inhalation mouthpiece. After passing this opening, the chambers are carried along a brush when the dosing wheel is further rotated, whereby powder which may have been left behind in the chamber is swept into a receiving space in order to prevent powder collecting in the chambers and too high a dose being dispensed. A single pressing of the control button results in the dosing wheel being displaced through one position, whereby only one filled chamber at a time is thus placed into communication with the inhalation mouthpiece and a single dose is thus dispensed.

Compared with conventional dosing devices, such as are marketed for instance by the company Astra under the name Turbuhaler, this dosing device has the advantage that it is considerably simpler to use. Thus, the conventional device, which was normally placed on an end surface of the container, first had to be turned over before dispensing so that powder could flow from the container to a dosing disc. In this overturned position the container and the dosing disc herein had to be rotated relative to one another, whereafter the device had to be placed in a horizontal position to enable inhalation of the metered powder. This involved the user requiring two hands to operate the conventional device. In contrast, the dosing device according to US-A-5 437 270 can be operated simply with one hand by pressing the control button. Furthermore, due to the presence of a resetting spring in the operating mechanism, the button always returns automatically to its starting position at the end of an operating movement.

The known dosing device has the drawback however that it is of relatively complicated structure and, in addition, cannot be adapted readily for dosing different quantities, since the dispensed dose is determined by the dimensions of the chambers in the dosing wheel and is therefore fixed at a determined size of these chambers . Because the dimensioning of all openings in the known dosing device is adapted to the dimensions of the chambers, the whole device will therefore have to be adapted in order to change the dose to be dispensed. The present invention has for its object to provide an improved dosing device of the above described type, wherein this drawback does not occur. According to the invention this is achieved in that the dosing means are adapted for continuous transport of material from the container directly to the dispensing opening and are displaceable through a limited stroke by the operating means. The dose for dispensing can in this manner be simply adjusted by adapting the stroke through which the dosing means can be displaced. The movement of the operating means is preferably bounded herein, for instance by placing a stop.

The dosing means are preferably rotatable. A relatively compact construction is hereby obtained. Easy operation, for instance by performing a squeezing movement, is then obtained when the operating means are movable substantially in a straight line and a transmission is arranged between the operating means and dosing means. This can then be achieved advantageously, at least when the operating means are movable counter to a spring bias, in that the transmission is adapted to connect the operating means and the dosing means during the operating movement and to disconnect them during a return movement under the influence of the spring bias . Thus is ensured that never more than one dose of material is dispensed during the operating movement.

A structurally simple embodiment of the transmission is obtained when this latter comprises a gear rack connected to the operating means and, co-acting therewith, a toothed wheel connected to the dosing means, and one outer end of the gear rack co-acts with loopshaped guide means. With these loop-shaped guide means the gear rack is placed into engagement with the toothed wheel during the operating movement and is guided at a distance along the toothed wheel during the return movement .

An accurate dosage can be obtained in simple manner when the dosing means comprise a screw conveyor arranged in the container and having an end part closing the dispensing opening, and a helical groove of the screw conveyor extends through the end par . The operating means can herein be adapted to cause the screw conveyor to rotate through at least one half rotation, whereby the helical groove leading into the end part is displaced between two rest positions staggered through 180°.

In order to prevent the administration of an overdose as a result of inhaling a new dose together with remnants of previous doses, the device preferably has means arranged in the vicinity of the dispensing opening for removing the material left behind after dosing. These removing means are advantageously connected in controllable manner to the operating means, wherein the operating means can be adapted to operate the removing means during the return movement under the influence of the spring bias. Thus is ensured that, after each operating movement wherein a dose of material is dispensed, remnants of this dose of material which may have been left behind are removed immediately.

A structurally simple embodiment is herein obtained when the removing means comprise a scraper member movable along the dispensing opening and the operating means have a carrier for placing into engagement with the scraper member. The scraper member can herein be movable counter to a spring bias so that it always returns to its starting position. The carrier advantageously has at least one control cam co-acting with a guide connected to the container, whereby the carrier-is placed-as-required in or out of engagement with the scraper member. For collection of the removed material a second container is preferably present which co-acts with the removing means so that this material, which will generally be a medicine, is prevented from being released into the environment in uncontrolled manner . In order to enable use of the dosing device as inhaler, the device preferably has an inhalation mouthpiece connected to the dispensing opening.

The device is now elucidated on the basis of two embodiments, wherein reference is made to the annexed drawing, in which: figure 1 is a schematic, perspective view of a first embodiment of the dosing device according to the invention before use; figure 2 is a longitudinal section through the device of figure 1 along the line II-II, wherein the inhalation mouthpiece has been removed; figure 3 is a schematic bottom view of the transmission between the operating means and the dosing means in figure 2 ; figure 4 is a view corresponding with figure 2 of the dosing device at the end of an operating movement; figure 5 is a view corresponding with figure 3 of the transmission in the situation shown in figure 4; figure 6 is a schematic, perspective view with exploded parts of the top part of the container and removing means co-acting therewith; figure 7 is a cross- sectional view on enlarged scale corresponding with figures 2 and 4 in which the removal of left-over material is shown; figures 8A-E show schematically the operation of the removing means ; figure 9 is a longitudinal section through the upper part of a dosing device according to an alternative embodiment of the invention; and figure 10 is a schematic perspective view of a carrier applied in this embodiment.

A dosing device 1 for a powder- form or granular material comprises a housing 2 (figure 1) , in which is arranged a container 5 for the material 8 (figure 2) as well as operating means 3 which are arranged slidably in housing 2 and which co-act with dosing means 44 arranged in the vicinity of a dispensing opening 6 of container 5. Dosing device 1 further comprises an inhalation mouthpiece 4 connected to dispensing opening 6.

Operating means 3 comprise a handgrip 18 which in the shown example, as stated, is arranged slidably, i.e. linearly movable, in housing 2. Side walls 48, 49 and bottom 46, 47 of handgrip 18 and housing 2 herein form sliding surfaces . Further arranged between operating handgrip 18 and housing 2 is a pressure spring 19 which is received on shaft ends 24, 25 of operating handgrip 18 respectively housing 2, and which urges operating handgrip 18 back to its rest position.

In the shown embodiment container 5 is cylindrical and provided on its end remote from dispensing opening 6 with a sealing cap 11. The material 8 in container 5 is urged in the direction of dispensing opening 6 by a piston 9, which is biased by a pressure spring 10 in the direction of dispensing opening 6. Piston 9 is provided in the middle with an opening 51 and is slidable round a shaft part 51 of a screw conveyor 12 which forms part of dosing means 44. Screw conveyor 12 is adapted for continuous transport of material 8 from container 5 to dispensing opening 6 and is provided at the top with a continuous helical groove 13 leading to an end part 14 which sealingly closes dispensing opening 6 of container 5. For this purpose the end part 15 of helical groove 13 is practically parallel to the shaft 51 of screw 12 and thus forms the actual dosing opening.

Arranged between screw conveyor 12 ^'and operating handgrip 18 is a transmission 45 whereby the linear movement of operating handgrip 18 is converted into a rotation movement of screw conveyor 12. For this purpose transmission 45 comprises a toothed wheel 16 connected to the screw conveyor and a gear rack 17 which can be placed into engagement with the wheel and which is connected to operating handgrip 18. During the operating movement of handgrip 18 the gear rack 17 is in engagement with toothed wheel 16 but, at the end of this movement when handgrip 18 is fully pressed in (figure 4) , is disengaged from toothed wheel 16, so that during the return movement of handgrip 18 the toothed wheel 16, and thereby the screw conveyor 12, are not rotated back again under the influence of the force of spring 19. For this purpose, one outer end of gear rack 17 is pivotally connected by means of a shaft 20 to handgrip 18, while the other outer end is provided with a pin 21 which co-acts with guide means 22 which are connected fixedly to housing 2 and thus to container 5. These guide means 22 comprise a loop-shaped guide track 23 in which pin 21 is received. Owing to the loop shape of guide track 23, the free outer end of gear rack 17 is placed practically transversely of the direction of the operating movement and is thereby disengaged from toothed wheel 16 (figure 5) . By squeezing the operating handgrip 18 the screw conveyor 12 is thus rotated, whereby material 8 is transported upward through helical groove 13 to the opening 15 (figure 4) , whereafter the user can inhale the thus dosed material . After inhalation the operating handgrip 18 can be released, whereafter it returns to its starting position under the influence of the spring bias without screw conveyor 12 being further rotated herein.

In order to prevent material which has been dosed but not inhaled by the user still being inhaled during subsequent use, whereby in combination with the new dose an overdose could be formed, means 27 are arranged in the vicinity of dispensing opening 6 for removing left-over material. These removing means 27 are likewise operated by operating means 3, this during the return movement thereof. For this purpose the removing means 27 comprise a scraper member 28 which is movable along dispensing opening 6 and is provided with an opening 36 which virtually corresponds with dispensing opening 6 and which is divided by means of a bridge piece 37 into two half-openings 38 and 39. Scraper member 28 is provided with protruding cams 40 which can be placed in engagement with carriers 35 connected to operating handgrip 18. Scraper member 28 is further connected to a pressure spring 30 which supports against the inside of operating handgrip 18 and whereby scraper member 28 is biased to its rest position. In order to place carriers 35 as required in or out of contact with cams 40 of scraper member 28, the carriers are arranged on spring arms 31 which are connected to operating handgrip 18 and are provided with control cams 32 which co-act with guides 33 in the side walls 34 of housing 2. In the shown embodiment each guide 33 takes the form of a profiled cam track with a widened part 42 and a downward bending part 43.

In the rest position of the device, each control cam 32 is situated at the beginning of the cam track 33 (figure 8A) . During squeezing of the operating handgrip the control cam 32 is moved to the left in the figure, wherein it follows the track 33 having therein the curved part 43, so that arm 31 will be bent downward and carrier 35 is also moved downward. With a continued movement of operating handgrip 18 the control cam 43 arrives at the widened part 42 and finally comes into contact with cam 40 of scraper member 28. Since scraper member 28 rests against the rear wall 49 of housing 2, it will not move, so that carrier 35 is urged downward by cam 40 while arm 31 bends. Cam 32 can follow this movement because -su ficient space is provided in widened part 42 for this purpose. After carrier 35 has passed over the cam of scraper member 28, the arm 31 springs upward again, whereby carrier 35 will hook behind cam 40 (figure 8C) . Operating handgrip 18 has now reached the end of its stroke so that a dose of material is dispensed which can be inhaled by the user. When operating handgrip 18 is now released and moves back to the right in the figure under the influence of the spring bias, the scraper member 28 is herein carried along by the carriers 35 hooked behind cams 40 (figure 8D) . Any material which may have been left behind on the top part of end part 14 of the screw conveyor is herein scraped off by bridge piece 37 and edge 52 of opening 36 and finally drops into a second container 26 placed adjacently of the first container 5 (figure 7) . During this movement of scraper member 28 the biasing spring 30 is compressed. When control cam 32 now reaches the curved part 43 of guide track 33 it is urged downward, whereby carrier 35 is disengaged from a cam 40. Under the influence of the biasing force of spring 30 the scraper member 28 is then urged back to its starting position (figure 8D) , in which the dispensing opening 6 is left clear and second container 26 is closed. In this way the excess material is prevented from being released into the environment in uncontrolled manner. In the starting position the opening 15 in end part 14 is otherwise covered by bridge piece 37, so that no material can escape therefrom either. In this way one dose at a time is dispensed when the device is operated, which dose can be inhaled by a user, whereafter possibly left-over material is disposed of in safe manner without a conscious operation of the user being required for this purpose. The device is moreover simple to use with one hand, since the operating means are movable linearly and can thus be easily squeezed and return automatically to their starting position under the influence of a spring. In a structurally slightly more simplified embodiment (figure 9) , the control cam 32 does not co-act with a cam track 33 recessed into side wall 34 but instead with a fixed cam 53 protruding from the side wall. Control cam 32 is herein provided with an inclining bottom surface 54 whereby arm 31 is bent slightly upward when it reaches fixed cam 53. If the operating handgrip 18 is moved further, carrier 35 then comes into engagement with cam 40 of slide member 28 and is pressed thereunder as a result of the inclining contact surfaces. During the return movement of operating handgrip 18, wherein carrier 35 is hooked behind cam 40 of slide member 28, control cam 32 comes with its inclining rear surface 55 in contact with the fixed cam 53 in housing 2, whereby arm 31 w ll be bent downward and carrier 35 disengages from cam 40 of scraper member 28 which returns to its starting position under the influence of pressure spring 30. It will be apparent that the invention is not limited to the embodiments shown and described here. Instead of a slidable operating handgrip use could for instance be made of a p votable handgrip or trigger with which a practically linear movement is also achieved. A rotatable operating member, for instance a turning knob, can however also be envisaged. There would hereby be no necessity for a transmission.

In addition, forms of continuously operating dosing means other than the screw conveyor shown here can be considered, for instance slide mechanisms and the like. Also the manner m which the movement of the operating means s bounded could also be embodied otherwise than shown here. A simple stop can for instance be envisaged here. Finally, the scraper member could also be embodied for instance pivotally instead of slidably.

The scope of the invention is therefore defined solely by the following claims .

Claims

1. Device for dosed dispensing of a powder-form or granular material, provided with a container for the material having at least one dispensing opening through which a user can suck up the dosed material, operable dosing means arranged in the vicinity of the dispensing opening and_ operating means co-acting with the dosing means and movable manually by the user, wherein the dosing means are adapted to dispense a single dose of material at an operating movement of the operating means, characterized in that the dosing means are adapted for continuous transport of material from the container directly to the dispensing opening and are displaceable through a limited stroke by the operating means.

2. Dosing device as claimed in claim 1, characterized in that the movement of the operating means is bounded.

3. Dosing device as claimed in claim 1 or 2 , characterized in that the dosing means are rotatable.

4. Dosing device as claimed in claim 3, characterized in that the operating means are movable substantially linearly and a transmission is arranged between the operating means and dosing means.

5. Dosing device as claimed in any of the foregoing claims, characterized in that the operating means are movable counter to a spring bias.

6. Dosing device as claimed in claims 4 and 5, characterized in that the transmission is adapted to connect the operating means and the dosing means during the operating movement and to disconnect them during a return movement under the influence of the spring bias.

7. Dosing device as claimed in claim 6, characterized in that the transmission comprises a gear rack connected to the operating means and, co-acting therewith, a toothed wheel connected to the dosing means, and one outer end of the gear rack co-acts with loop-shaped guide means.

8. Dosing device as claimed in any of the claims 3-7, characterized in that the dosing means comprise a screw conveyor arranged in the container and having an end part closing the dispensing opening, and a helical groove of the screw conveyor extends through the end part .

9. Dosing device as claimed in claim 8, characterized in that the operating means are adapted to cause the screw conveyor to rotate through at ^"least one half rotation.

10. Dosing device as claimed in any of the foregoing claims, characterized by means arranged in the vicinity of a dispensing opening for removing material left behind after dosing.

11. Dosing device as claimed in claim 10, characterized in that the removing means are connected in controllable manner to the operating means.

12. Dosing device as claimed in claim 11, characterized in that the operating means are adapted to operate the removing means during the return movement under the influence of the spring bias.

13. Dosing device as claimed in claim 11 or 12, characterized in that the removing means comprise a scraper member movable along the dispensing opening and the operating means have a carrier for placing into engagement with the scraper member.

14. Dosing device as claimed in claim 13, characterized in that the scraper member is movable counter to a spring bias .

15. Dosing device as claimed in claim 13 or 14, characterized in that the carrier has at least one control cam which co-acts with a guide connected to the container .

16. Dosing device as claimed in any of the claims 10-15, characterized by a second container co- acting with the removing means for receiving the removed material .

17. Dosing device as claimed in any of the foregoing claims, characterized by an inhalation mouthpiece connected to the dispensing opening.