Abstract:
The invention relates to a capsule opening arrangement for a powder inhaler device. The arrangement has a first part and a second part which are relatively movable with respect to one another. The first part has a capsule support including an aperture for supporting at least one severable capsule. The second part contains a capsule severing device fixedly located therein so as to pass across the supporting aperture during relative movement of the first and second parts. The opening arrangement provides particular advantages in that the capsule, after severing, has a large open area from which powder can be extracted without any part of the capsule interfering with the powder flow.

Description:
This application is a continuation of application Ser. No 09/117,385, filed on Sep. 21, 1998, now ABN for which priority is claimed under 35 U.S.C. § 120. Application Ser. No. 09/117,385 is the national phase of PCT International Application No. PCT/SE97/00120 filed on Jan. 27, 1997 under 35 U.S.C. § 371. The entire contents of each of the above-identified applications are hereby incorporated by reference. This application also claims priority of application Ser. No. 9600306-6 filed in Sweden on Jan. 29, 1996 under 35 U.S.C. § 119. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to a capsule opening arrangement for a powder inhaler device according to the preamble of claim  1 . In particular, the invention relates to a capsule severing arrangement. 
     BACKGROUND TO THE INVENTION 
     Several types of powder inhaler devices are known in the prior art. One of these types is a device which uses capsules containing powder, said capsules needing to be opened before the device can be operated by a user. 
     Two main types of device are available for opening such capsules. The first is a pin arrangement within the inhaler device, said pin being operable so as to pierce a capsule and thus allow access to its contents. Such a device is known from U.S. Pat. No. 4 069 819 for example. Due to the presence of a reduced pressure around the powder capsule when a user inhales, and due to a processional motion of the capsule in a restricted cavity, the powder is withdrawn therefrom. 
     The second type of device for opening such capsules is a device which separates a two-part capsule into its two parts by first clamping one part and then forcing the other part away therefrom. An example of such a device is disclosed in WO-A-91/19524, said device corresponding to the features defined in the preamble of claim  1 . 
     Such devices suffer from several disadvantages. The pin-piercing device produces a relatively small opening within the capsule and may thus lead to it not being completely emptied. Although the problem can be alleviated to some extent by providing multiple piercing elements, variations in the dose provided may still be observed. 
     The capsule-separation device relies on the capsule being of the separable type. Additionally, the separation of the capsules relies to a great extent on a good balance between capsule shell hardness and separation force required to separate the two parts. Moreover, even when separation is achieved, the loose parts are left to block the flow passage of the powder. Furthermore a grid structure is also required, on which powder may accumulate and cause blockage. 
     SUMMARY OF THE PRESENT INVENTION 
     The present invention seeks to provide a solution to the aforementioned problems by means of a capsule opening arrangement having the features defined in appended claim  1 . 
     Preferred features of the invention are defined in the dependent claims. 
     In a particularly preferred embodiment of the invention, the opening device is intended to be attached, or integral with, the powder inhaler of the type disclosed in WO-A95/03846. To avoid repetition of the principal of operation of such device, which will be clear to the skilled man upon reading said document, specific reference is hereby made to said document in its entirety. 
     Although the invention will be elucidated by reference to a particular form of a device of the type according to WOA-95/03846, it will be understood by the skilled man that the capsule opening device of the present invention will also be applicable to other forms of inhaler devices. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will now be described in more detail with reference to the accompanying drawings, in which: 
     FIG. 1 is a schematic view of a powder inhaler device having an upper and lower section, said lower section containing the capsule opening arrangement of the invention, 
     FIG. 2 is an exploded view of the powder inhaler device of FIG. 1, depicting its various component parts, 
     FIG. 3 is a cross-sectional view through the central rotational axis of the device, in which the cover of the capsule opening device has been opened, 
     FIG. 4 is an end view on to the base of the device depicted in FIG. 3, 
     FIG. 5 is a view similar to FIG. 3 but with the cover closed, 
     FIG. 6 is an end view on to the base of the cover depicted in FIG. 5, 
     FIG. 7 depicts an enlarged view of the severing means of the capsule opening device together with indications showing superimposed capsule movement and the edge of the entrance to the capsule receiving cavity, and 
     FIG. 8 depicts a cross-sectional view of a further embodiment of the device, similar to the view in FIG. 5, but with a severed capsule in place and being provided with an airflow passageway which eases capsule-emptying. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The inhaler device depicted in FIG. 1 has a lower section A and an upper section B. The lower section A contains the capsule opening arrangement of the invention, whilst the upper section B contains a united tubular mouthpiece/chamber  1  of the inhaler, sealed by a cover member  2 . The cover member is removably attached to the upper mouthpiece/chamber  1  by means of threads  3  for example. Other means of removable attachment may of course be used instead of threads. The thread  3  attachment is shown only schematically in FIG.  1 . 
     The external profile of the mouthpiece, even though hidden by the cover, has been drawn in solid lines in FIG. 1 so as to show a differentiation compared to the inner passageway of said mouthpiece/chamber which is shown in dashed lines. Said mouthpiece/chamber portion corresponds basically to that disclosed in WO-A-95/03846. 
     The lower section A is divided into first and second parts  4  and  5 . The second part  5  is non-rotatably attached to mouthpiece/chamber  1  and first part  4  is rotatably mounted relative to said second part  5 . An indicator arrow  6 , moulded into part  4 , indicates the relative position with respect to an indicator  7  on the second part  5 . 
     In the example to be described, the lower section A contains four capsules. Thus, four markings (and possibly also a further one, “L”) are provided around the outer surface of the second part. 
     In the exploded view in FIG. 2, the various structural elements can be seen in more detail. The first part  4  comprises two constituent parts  8  and  9 . Part  8  is a cover member for the lower part of the device and serves to maintain the four severable capsules  11  within the other part  9  which is a capsule supporting means. Parts  8  and  9  are preferably hingedly attached to one another. 
     The capsule supporting means  9  has at least one capsule supporting aperture  10 . In the depicted embodiment there are four capsule supporting apertures  10 . The apertures  10  are formed such that the capsules may be easily fitted into place within said apertures, without a large amount of play. The capsules  11  may be a press fit into the apertures  10 . The capsules  11  are normally made of relatively flexible material such as a gelatine compound (known per se) and may typically contain between 5 mg and 40 mg of powder substance to be inhaled, although such amounts are not limiting for the invention. 
     In the centre of the part  9  there is an aperture  12 . This aperture  12  fits around a projection  13  on the second part  5  when the device is ready for use. This fitted relationship is shown in FIG.  3 . 
     Second part  5  is comprised of three pieces fitted together. The first piece is a severing means in the form of a flat knife blade  14  having a severing edge  17 . The second piece is a knife blade support means  20 , and the third piece a chamber section  23  united with the mouthpiece (either integrally or by attachment of said parts). 
     The knife blade  14  has a two apertures therethrough. The first aperture  15  is formed by a substantially annular portion  45 . Said portion  45  fits, preferably as a push-fit, around the partially annular, projecting portion  13  of said blade support means  20 . 
     The blade support means  20  has a surface  18  formed therein which is recessed with respect to the lower planar surface  21  of said support means  20  by the thickness of said knife blade  14 . The knife blade is thus supported in position by two means and its lower surface is flush with the planar surface(s)  46  outside the recess. 
     The second aperture  16  in the knife blade  14  is positioned in line with a powder exit passageway  22  which passes from the lower side of said blade support means  20  to the upper side (i.e. the chamber side) thereof. It should be understood that the expression “in line with” is intended here to mean that the aperture  16  and the passageway  22  are in direct communication with one another. However the aperture  16  and the passageway  22  inlet do not need to be the same shape or size, and indeed will often be different (see e.g. the arrangement shown in FIG.  8 ). The exact shape and/or size will depend on the design chosen. 
     The blade  14  is shown in larger detail in FIG.  7 . The outside of the knife blade is preferably in the form of a circular arc  31  and fits closely to the circular inner wall perimeter of blade support means  20 . 
     The blade support means  20  comprises a receiving cavity  19  for receiving portions of said capsules  11  which are severed by knife edge  17 . A large portion of said cavity  19  is positioned above said knife blade  14 . With the knife blade  14  in place (not shown in FIG.  2 ), the receiving cavity  19  has a single entrance  24  extending on one side of said cutting edge  17  (i.e. to the anti-clockwise side as seen in the view in FIG.  2 ). The position of said entrance is also shown in FIG.  7 . 
     The blade support means  20  further comprises a capsule end guide channel  25  allowing sliding contact with the ends of each of said capsules during their rotational indexed movement. One end of said guide channel  25  also forms the single entrance  24  of the receiving cavity  19 . 
     On the chamber side of the blade support means  20  there is a central projecting member  26  which fits into the chamber  35  (see e.g. FIG. 5) to create a flow restriction between the chamber and the mouthpiece (see also WO-A-91/19524). A freely movable element  27  is also contained therein (see WO-A-91/19524). 
     Part  20  is attached to part  23  so that no relative movement between said parts occurs during normal use. However, part  9  is attached so as to be rotatably received at its outer edge within the lower part of the wall portion  28  of part  23 . As shown in FIG. 3, this is achieved by a radially inwardly projecting portion  32  engaging (e.g. as a snap-fit) into a groove  33  in part  23 . 
     FIG. 4 shows an end view of said inhaler from the lower end. Here it can be seen that none of the four capsule support apertures is aligned with the passageway  22 . An indexed rotation of about 72° is required for such alignment between one aperture  10  and said passageway in the depicted embodiment, presuming the apertures to be equally angularly spaced. 
     Part  9  is arranged to be rotatably indexed between various positions, so that opened capsules will assume an indexed position aligned with the powder exit passageway  22 . In order to accomplish this, an indexing means is provided between part  9  and part  20 / 23 . Such an indexing means is shown in FIGS. 3 and 4 by element  47  which is a sprung arm which can be moved out of its detent position by a sufficient rotational force in a rotational direction towards knife edge  17  applied between parts  9  and  5 . 
     FIGS. 5 and 6 show the inhaler according to FIGS. 3 and 4, with the lower cap in a closed state. In the bottom of the cap are semi-spherical recesses  34  which align with capsule support apertures  10 . Together with channel  25 , these elements  10  and  34  form the supporting and guiding elements for said capsules. 
     In FIG. 5, a severed capsule (not shown) will be positioned within the space bounded by the lower edge of the blade aperture  16  and the recess  34 . In this manner a direct flow communication is established between chamber  35  and the inside of a severed capsule (not shown in FIG.  5 ). FIG. 6 shows an end view of the lower part  8  in FIG.  5 . 
     FIG. 7 shows an enlarged view, from below, of the knife blade  14  depicted in FIG.  1 . The size, and even the shape, of the apertures  15  and  16  may vary according to circumstances, although generally the internal diameter of aperture  15  will be a push-fit with respect to the outer periphery of projection  13 . Although the knife is preferably made of steel and the rest of the inhaler of plastics, the knife may also be made of plastics. 
     FIG. 7 also schematically shows a horizontal section through capsule  11  by means of dotted lines. The capsule moves in a circular arc as indicated by arrow C (by rotational movement of part  9  having apertures  10 ) towards the knife edge  17 . The capsule will start from a first indexed position in which it is temporarily held upstream of the knife edge by some blocking or detent means (e.g. a ratchet or the like). Upon forward movement and upon reaching the knife edge, it will be pierced. Continued movement of the capsule in the direction of arrow C will result in the top thereof being cut off (severed) and moving into the entrance  24  of the receiving cavity  19 . Still further movement of the capsule will allow the severed capsule to reach its second indexed position directly below the aperture  16 . In this position, the powder contents of the capsule will then be in direct communication with passageway  22  and can be withdrawn by sucking through mouthpiece  1 . 
     During movement of the capsule  11 , which is supported in aperture  10  of part  9 , the upper, generally planar, surface  43  of said part  9  will be in sliding contact with the lower surface of the knife  14  and the surface  46  with which it is flush. In this way, the severed capsule remaining in the part  9  will have its upper severed surface also in sliding contact with the lower surface of knife  14  and thus will form a relatively good seal between the two parts. This seal will help ensure that the reduced pressure in chamber  35  will efficiently withdraw the powder from the severed capsule. 
     The upper parts of the capsule  11  which enter into the cavity  19  via entrance  24  are held in the cavity which is bounded partly by the knife blade upper surface and surface  36  of cover  8  (see FIG. 5) and also the upper planar surface of part  9 . Since the entrance  24  is always sealed by the upper planar surface of part  9  (apart from when actually severing a capsule), no capsule parts can fall out and block the device. Removal of said capsule parts is effected only by opening lower end cap  8  which move from cavity  19 , through an open space  44  in the middle of part  9  and to the outside of the device. 
     When operating the device as described above, the inhaler should be kept upright as shown in e.g. FIG.  5 . Otherwise there is a risk of powder exiting the capsule prematurely and ending up in the cavity  19 . 
     In the further embodiment of the invention shown in FIG. 8, which corresponds in most aspects to FIG. 5, an air passageway  39  from the surroundings is arranged in said mouthpiece/chamber portion  1  and in said second portion  9 . 
     An air passageway is thus formed from the surroundings, directly through said mouthpiece/chamber portion and said second part  9 , as well as through said aperture  16   a  in the knife  14 . The passageway  39  is thus in communication with said aperture  10  (or a severed capsule  11  if one is present). The aperture  16   a  will thus be larger, or of a different shape, compared to aperture  16  in FIG. 5, all other things being equal. 
     When a suction force is applied to the open end  41  of mouthpiece  1 , air will be sucked through apertures  42  into the chamber to create the required swirling effect (see WOA-95/03846). Similarly, air will also be drawn in through passageway  39 , and will impinge onto the powder  40  within the severed capsule  11  and draw it along with the flow into the swirling air in chamber  35 . In this way, emptying of the capsule is facilitated to a greater degree compared to the arrangement shown in FIG.  5 . 
     The passageway  39  is preferably arranged so that its longitudinal axis is directed to a point impinging onto the passageway-side of the capsule, as shown in FIG.  8 . In this way all the air will tend to act in one direction when moving through the capsule, rather than merely creating counteractive turbulence within the capsule, as would be the case if the passageway were directed to the other side of the capsule  11 . 
     As will be clear from the a foregoing, the provision of an air passageway, as described, for emptying a severed capsule in an inhaler device, is an aspect of the invention which can be used independently of the exact type of opening means used, as long as an opened upright capsule will be presented for use. Its subject matter, in the broadest sense, may thus form an independent invention. 
     However its use with the arrangement of the present invention is particularly preferred. 
     Similarly, the provision of the particular severed capsule receiving cavity, in its broadest sense, by which severed portions of capsules are removed from interference with the airstream or powder stream flow in inhaler devices, is an aspect of the invention which can be the subject matter of an independent invention. Its use in the arrangement of the present invention is however preferred. 
     An indexing detent means  37  is shown on one side of the capsule opening means. Said detent means may be of any suitable type, several of which are known to the skilled man and which therefore do not need to be described in more detail. 
     Radially outwardly of the inlet to the passageway  39  is a ledge  38 . Said ledge  38  is so arranged such that when a cover  2  (as in FIG. 1) is fitted over the mouthpiece  1 , the inner surface of said cover  2  will seal the passageway  39  from the surroundings. 
     Although the invention has been described above with reference to particular embodiments of the invention depicted in the drawings, it is to be understood that such embodiments are not limiting for the invention, the scope of which is defined by the following claims. 
     For example, the type of capsule used does not need to be a two-part capsule, but may be any other type of severable capsule. Similarly, whilst the capsule has been shown as being generally oval and having two parts of different outer diameter attached to each other, other shapes of capsule may be used.