Abstract:
A dispensing apparatus (for delivering metered doses from a pressurized dispensing container) having a housing receiving the container and a dose counter with dose indication element. The dose counter has an indexing mechanism advancing the indication element on container actuation. The dispensing apparatus has an indexing member moving within the housing in sync with the container wherein on actuation of the container in a normal mode of operation the indexing member interfaces with the indexing mechanism to apply a force to the indexing mechanism to incrementally advance the indication element. The indexing member and mechanism are configured to cooperate with one another, upon the input of a force in a second mode, such that the indexing mechanism transmits a force to the indexing member sufficient to generate a relative displacing movement between the indexing member and mechanism without incurring incremental advancement of the indication element.

Description:
FIELD OF THE INVENTION 
     This invention relates to dispensing apparatus having integral dosage counting devices which require an axial force for actuation. 
     BACKGROUND OF THE INVENTION 
     It has been recognised that there is a need to provide accurate information to a user of a dose-dispensing delivery apparatus, such as a pressurised metered dose inhaler, concerning the number of doses delivered from, or remaining in, the dispensing apparatus. Without such information, there is a danger that a user will forget how many doses have been delivered and hence take a greater or fewer number of doses than are required. There is also a danger that a user may be unaware that the dispensing container of the dispensing apparatus is empty or close to empty. This is especially dangerous where the dispensing apparatus is for use in delivering medicinal compounds for the treatment of chronic or acute symptoms, for example, as in the case of a pressurised metered dose inhaler used for treating asthmatic reactions. 
     It is known to provide a dispensing apparatus with a dose counting device. Typically such dose counting devices are triggered by movement of the dispensing container wherein the movement either directly or indirectly provides the motive force for incrementing or decrementing the dose counting device. In order for a dose counting device to be accurate it must be designed not to under-count the number of doses dispensed from the dispensing container, otherwise a user may be misled into thinking that the dispensing apparatus has a greater number of remaining doses than is actually the case. There has therefore been a desire to develop dose counting devices where movement of the dispensing container into its actuated position in the dispensing apparatus is not possible without incrementing or decrementing the dose counter device. In this way under-counting is prevented. However, a disadvantage of such dispensing apparatus is that actuation of the dispensing container is not possible if the dose counting device should inadvertently jam or become inoperative for some other reason. There is then the danger that a user would not be able to actuate the dispensing container despite there being available doses therein. 
     There can also be a problem with known mechanical dosage counters in that they are prone to accidentally incrementing if the apparatus is dropped due to impact forces imparted on the counting mechanism. 
     Mechanical dose counters can also be difficult to manufacture so that they work reliably. One problem is that a mechanical dose counter typically requires a number of components which must be accurately located relative to one another during assembly to ensure that over-counting or under-counting is not experienced. This can lead to a requirement for very strict manufacturing tolerances which can make manufacture expensive. 
     SUMMARY OF THE INVENTION 
     According to the present invention there is provided dispensing apparatus for delivering metered doses of product from a pressurised dispensing container comprising: 
     a housing for receiving a pressurised dispensing container; 
     a dose counting mechanism comprising indication means for displaying to a user an indication associated with the number or quantity of doses dispensed from, or the number or quantity of doses remaining in, the received pressurised dispensing container; 
     the dose counting mechanism further comprising an indexing mechanism for advancing the indication means on actuation of the received pressurised dispensing container; 
     wherein the dispensing apparatus comprises an indexing member capable of moving within the housing in sync with the received pressurised dispensing container; 
     wherein on actuation of the received pressurised dispensing container in a normal mode of operation the indexing member is able to interface with the indexing mechanism to apply a force to the indexing mechanism sufficient to incrementally advance the indication means; 
     wherein in the eventuality that the indexing mechanism or the indication means is jammed so as to prevent advancement, the indexing member and the indexing mechanism are enabled to move relative to one another in such a way to allow the indexing member to bypass the indexing mechanism to allow actuation of the received pressurised dispensing container. 
     In this way the dispensing apparatus may advantageously still be operated when parts of the counting mechanism may have become jammed or otherwise inoperative. 
     The indexing mechanism may move to achieve the bypass. The indexing mechanism may be able to flex to allow the indexing member to bypass the indexing mechanism to allow actuation of the received pressurised dispensing container. 
     Alternatively, the indexing member may move to achieve the bypass. 
     The indexing member may be able to slide, pivot, retract or similar to bypass the indexing mechanism to allow actuation of the received pressurised dispensing container. 
     Preferably in the eventuality that the indexing mechanism or the indication means is jammed so as to prevent advancement the indexing mechanism is capable of applying a force to the indexing member sufficient to flex the indexing member such that the indexing member is able to bypass the indexing mechanism. 
     The indexing member may exhibit a degree of inherent flexibility. 
     The indexing member may flex elastically as it bypasses the indexing mechanism. 
     Preferably, the indexing member is capable of moving along a longitudinal axis of the housing in sync with the received pressurised dispensing container. 
     In one embodiment the longitudinal movement of the indexing member interfaces with the indexing mechanism to produce a rotational movement of the indication means about the longitudinal axis. 
     Preferably the indexing member comprises an elongate portion aligned substantially with the longitudinal axis of the housing. 
     Preferably flexure of the elongate portion of the indexing member allows the indexing member to move out of alignment with the longitudinal axis of the housing to allow by-pass of the indexing mechanism. 
     The indexing member may comprise a cantilevered portion having a free distal end which interfaces in use with the indexing mechanism. 
     The cantilevered portion of the indexing member may depend from a flexure point of the dispensing apparatus. 
     The apparatus may further comprise a sleeve for receiving in use the pressurised dispensing container. 
     Preferably the indexing member is joined to or formed as part of the sleeve. 
     The indexing member may comprise a cantilevered portion having a free distal end which interfaces in use with the indexing mechanism, the indexing member depending from a flexure point of the dispensing apparatus, wherein a void space is provided around the cantilevered portion to accommodate flexure of the indexing member. 
     The dose counting mechanism may comprise one or more annular members. 
     The one or more annular members may be orientated for rotation about the longitudinal axis of the housing. 
     In use, the pressurised dispensing container may be received within the housing such that the one or more annular members surround the pressurised dispensing container. 
     The indexing mechanism may comprise a plurality of angled teeth which interface with the indexing member on longitudinal movement of the indexing member to produce rotation of the one or more annular members. 
     Preferably the indexing member is formed from acetal, ABS or nylon. 
     Preferably the sleeve is formed from acetal, ABS or nylon. 
     The present invention also provides dispensing apparatus for delivering metered doses of product from a pressurised dispensing container comprising: 
     a housing for receiving a pressurised dispensing container; 
     a dose counting mechanism comprising indication means for displaying to a user an indication associated with the number or quantity of doses dispensed from, or the number or quantity of doses remaining in, the received pressurised dispensing container; 
     the dose counting mechanism further comprising an indexing mechanism for advancing the indication means on actuation of the received pressurised dispensing container; 
     wherein the dispensing apparatus comprises an indexing member capable of moving within the housing in sync with the received pressurised dispensing container; 
     wherein on actuation of the received pressurised dispensing container the indexing member is able to interface with the indexing mechanism to apply a force to the indexing mechanism sufficient to incrementally advance the indication means; 
     wherein the indexing member has a degree of inherent flexibility such that in the event of the dispensing apparatus suffering a sudden impact the indexing member is able to flex under impact loading to thereby lessen the chances of damaging the indexing mechanism. 
     Advantageously, the apparatus is better able to cope with sudden impacts without leading to damage of the indexing mechanism, in particular damage to the teeth of the annular members that preferably make up a part of the indexing mechanism. 
     The indexing member may comprise a cantilevered portion having a free distal end which interfaces in use with the indexing mechanism. 
     The cantilevered portion of the indexing member may depend from a flexure point of the dispensing apparatus. 
     The apparatus may further comprises a sleeve for receiving in use the pressurised dispensing container. 
     Preferably the indexing member is joined to or formed as part of the sleeve. 
     The indexing member may comprise a cantilevered portion having a free distal end which interfaces in use with the indexing mechanism, the indexing member depending from a flexure point of the dispensing apparatus, wherein a void space is provided around the cantilevered portion to accommodate flexure of the indexing member. 
     The dose counting mechanism may comprise one or more annular members. 
     The one or more annular members may be orientated for rotation about the longitudinal axis of the housing. 
     In use, the pressurised dispensing container may be received within the housing such that the one or more annular members surround the pressurised dispensing container. 
     The indexing mechanism may comprise a plurality of angled teeth which interface with the indexing member on longitudinal movement of the indexing member to produce rotation of the one or more annular members. 
     Preferably the indexing member is formed from acetal, ABS or nylon. 
     Preferably the sleeve is formed from acetal, ABS or nylon. 
     The present invention further provides dispensing apparatus for delivering metered doses of product from a pressurised dispensing container comprising: 
     a housing for receiving a pressurised dispensing container; 
     a dose counting mechanism comprising indication means for displaying to a user an indication associated with the number or quantity of doses dispensed from, or the number or quantity of doses remaining in, the received pressurised dispensing container; 
     the dose counting mechanism further comprising an indexing mechanism for advancing the indication means on actuation of the received pressurised dispensing container; 
     wherein the dispensing apparatus comprises first and second indexing members which together act to incrementally advance the indexing mechanism on actuation of the received pressurised dispensing container; 
     wherein movement of the received pressurised dispensing container in a first direction relative to the indexing mechanism causes the first indexing member to advance the indexing mechanism by a partial increment and also causes a strain to be imparted on the second indexing member; 
     wherein subsequent movement of the received pressurised dispensing container a second direction, opposed to the first direction, allows the second indexing member to move the indexing mechanism to complete the incremental advancement of the indexing mechanism by recovery of the imparted strain. 
     Advantageously, the use of two indexing members working together produces a more reliable mechanism with lower manufacturing tolerances. 
     Preferably the strain imparted on the second indexing member is in a different direction compared to the direction of movement of the first indexing member. 
     Preferably the strain imparted on the second indexing member is in a direction substantially perpendicular compared to the direction of movement of the first indexing member. 
     The first indexing member may be moveable parallel to the longitudinal axis of the received pressurised dispensing container. 
     The strain imparted on the second indexing member may be in a radial direction relative to the received pressurised dispensing container. 
     The first indexing member may comprise a cantilevered portion having a free distal end which interfaces in use with the indexing mechanism. 
     The cantilevered portion of the indexing member may comprise an elongate portion running parallel to the longitudinal axis of the received pressurised dispensing container. 
     The second indexing member may comprise a cantilevered portion having a free distal end which interfaces in use with the indexing mechanism. 
     The cantilevered portion of the second indexing member may comprise an arcuate portion running around the longitudinal axis of the received pressurised dispensing container. 
     Preferably a distal end of the second indexing member comprises an outwardly directed projection for engaging the indexing mechanism. 
     The indexing mechanism may comprise an annular member. 
     The annular member may comprise a first set of abutment surfaces for engagement with the first indexing member and a second set of abutment surfaces for engagement with the second indexing member. 
     Preferably the second set of abutment surfaces are formed by a circumferential series of inwardly directed projections of the annular member. The series of inwardly directed projections comprises interspaced peaks and troughs defined by the abutment surfaces. 
     Preferably a distal end of the second indexing member comprises an outwardly directed projection for engaging the second set of abutment surfaces. 
     The apparatus may further comprise a sleeve for receiving in use the pressurised dispensing container. 
     The first and second indexing members may be joined to or formed as part of the sleeve. 
     The dispensing apparatus may be a pharmaceutical dispensing device, such as, for example, a pulmonary, nasal, or sub-lingual delivery device. A preferred use of the dispensing apparatus is as a pharmaceutical metered dose aerosol inhaler device. The term pharmaceutical, as used herein, is intended to encompass any pharmaceutical, compound, composition, medicament, agent or product which can be delivered or administered to a human being or animal, for example pharmaceuticals, drugs, biological and medicinal products. Examples include antiallergics, analgesics, bronchodilators, antihistamines, therapeutic proteins and peptides, antitussives, anginal preparations, antibiotics, anti-inflammatory preparations, hormones, or sulfonamides, such as, for example, a vasoconstrictive amine, an enzyme, an alkaloid, or a steroid, including combinations of two or more thereof. In particular, examples include isoproterenol [alpha-(isopropylaminomethyl)protocatechuyl alcohol], phenylephrine, phenylpropanolamine, glucagon, adrenochrome, trypsin, epinephrine, ephedrine, narcotine, codeine, atropine, heparin, morphine, dihydromorphinone, ergotamine, scopolamine, methapyrilene, cyanocobalamin, terbutaline, rimiterol, salbutamol, flunisolide, colchicine, pirbuterol, beclomethasone, orciprenaline, fentanyl, and diamorphine, streptomycin, penicillin, procaine penicillin, tetracycline, chlorotetracycline and hydroxytetracycline, adrenocorticotropic hormone and adrenocortical hormones, such as cortisone, hydrocortisone, hydrocortisone acetate and prednisolone, insulin, cromolyn sodium, and mometasone, including combinations of two or more thereof. 
     The pharmaceutical may be used as either the free base or as one or more salts conventional in the art, such as, for example, acetate, benzenesulphonate, benzoate, bicarbonate, bitartrate, bromide, calcium edetate, camsylate, carbonate, chloride, citrate, dihydrochloride, edetate, edisylate, estolate, esylate, fumarate, fluceptate, gluconate, glutamate, glycollylarsanilate, hexylresorcinate, hydrobromide, hydrochloride, hydroxynaphthoate, iodide, isethionate, lactate, lactobionate, malate, maleate, mandelate, mesylate, methylbromide, methylnitrate, methylsulphate, mucate, napsylate, nitrate, pamoate, (embonate), pantothenate, phosphate, diphosphate, polygalacturonate, salicylate, stearate, subacetate, succinate, sulphate, tannate, tartrate, and triethiodide, including combinations of two or more thereof. Cationic salts may also be used, for example the alkali metals, e.g. Na and K, and ammonium salts and salts of amines known in the art to be pharmaceutically acceptable, for example glycine, ethylene diamine, choline, diethanolamine, triethanolamine, octadecylamine, diethylamine, triethylamine, 1-amino-2-propanol-amino-2-(hydroxymethyl)propane-1,3-diol, and 1-(3,4-dihydroxyphenyl)-2 isopropylaminoethanol. 
     The pharmaceutical will typically be one which is suitable for inhalation and may be provided in any suitable form for this purpose, for example as a solution or powder suspension in a solvent or carrier liquid, for example ethanol, or isopropyl alcohol. Typical propellants are HFA134a, HFA227 and di-methyl ether. 
     The pharmaceutical may, for example, be one which is suitable for the treatment of asthma. Examples include salbutamol, beclomethasone, salmeterol, fluticasone, formoterol, terbutaline, sodium chromoglycate, budesonide and flunisolide, and physiologically acceptable salts (for example salbutamol sulphate, salmeterol xinafoate, fluticasone propionate, beclomethasone dipropionate, and terbutaline sulphate), solvates and esters, including combinations of two or more thereof. Individual isomers such as, for example, R-salbutamol, may also be used. As will be appreciated, the pharmaceutical may comprise of one or more active ingredients, an example of which is flutiform, and may optionally be provided together with a suitable carrier, for example a liquid carrier. One or more surfactants may be included if desired. 
     Rigid components of the dispensing apparatus may be formed from, for example, from polyester, nylon, acetal or similar. 
     Preferably, the first and or second indexing members are formed of an elastic material such that imparted strains during normal actuation are recoverable elastically 
     In order that the invention may be fully disclosed, embodiments will now be described, by way of example, with reference to the accompanying drawings, in which:— 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a first embodiment of dispensing apparatus according to the present invention; 
         FIG. 2  is a cross-sectional view of the apparatus of  FIG. 1 ; 
         FIG. 3  is a perspective view of various internal features of the dispensing apparatus of  FIG. 1 ; 
         FIG. 4  is a perspective view of a cog forming part of the dispensing apparatus of  FIG. 1 ; 
         FIG. 5  is a perspective view of a sleeve forming part of the dispensing apparatus of  FIG. 1 ; 
         FIG. 6  is a perspective view of first and second number rings and a cog forming part of the dispensing apparatus of  FIG. 1 ; 
         FIG. 7  is a perspective view of a first number ring having two different diameter portions, forming part of the dispensing apparatus of  FIG. 1 ; 
         FIG. 8  is a perspective view of a second embodiment of dispensing apparatus according to the present invention; 
         FIG. 9  is a cross-sectional view of the apparatus of  FIG. 8 ; 
         FIG. 10  is a perspective view of various internal features of the dispensing apparatus of  FIG. 8 ; 
         FIG. 11  is a perspective view of first and second number rings and a cog forming part of the dispensing apparatus of  FIG. 8 ; 
         FIG. 12  is a perspective view of a cog forming part of the dispensing apparatus of  FIG. 8 ; 
         FIG. 13  is a perspective view of a sleeve forming part of the dispensing apparatus of  FIG. 8 ; 
         FIG. 14  is a perspective view of a first number ring having two different diameter portions, forming part of the dispensing apparatus of  FIG. 8 ; 
         FIG. 15  is a perspective view of the dispensing apparatus of  FIG. 8  with the mouthpiece detached and some parts shown in cross-section; and 
         FIG. 16  is a schematic view of part of the apparatus of  FIG. 8  with some parts omitted for clarity. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows a dispensing apparatus, indicated generally at  1 , having a cap  2 , a fixing collar  3 , a main body  5  and a detachable mouthpiece  20 . A dust cap may be used to cover the mouthpiece  20  when the apparatus is not in use. As shown in  FIG. 2 , the dispensing apparatus is also provided with first and second number rings  11 , 13 , a cog  12  and a sleeve  100 . In use the apparatus receives a pressurised dispensing container  10 . 
     The main body  5 , which is substantially cylindrical, comprises an enlarged portion  31 , and is open at its upper end. The enlarged portion  31 , situated at the upper end thereof,—in relation to the dispensing apparatus—houses the cog  12  and the first and second number rings  11 ,  13 . The number rings  11 ,  13  rest upon internal projections  110  of the main body  5 . Such internal projections  110  provide up-facing surfaces upon which the second number ring  13  may rest and rotate, during use. The first number ring  11  rests and rotates, during use, on top of the second number ring  13 . The cog  12  is rotatably mounted within the main body  5  on a cylindrical portion  112  and interacts with both first and second number rings  11 ,  13 . As can be seen, the axis of rotation of the cog  12  is offset from the axes of the numbered rings  11 ,  13  but parallel thereto so that the cog  12  can interact with both number rings  11 ,  13  which are housed in the substantially cylindrical part of the main body  5  without impeding axial movement of the container  10 . 
     The main body  5  is provided at a lower end thereof with an axial protrusion  121  integral with the main body  5 . The axial protrusion  121  comprises a hollow elongate portion into which the valve stem  22  of the container  10  can be received. The hollow portion is provided with a narrowed constriction against which the valve stem  22  can abut when the dispensing apparatus is actuated. The axial protrusion  121  protrudes from the lower end of the main body  5  as shown in  FIG. 2 . The axial protrusion  121  provides protection for the valve stem when the mouthpiece  20  has been removed. In particular with the mouthpiece  20  removed the valve stem  22  is not easily accessed as it is recessed relative to the distal end of the protrusion  121 . This significantly reduces the chance that the container  10  could be actuated by direct pressure being applied to the end of the valve stem  22  which might circumvent the dose counter mechanism. 
     The main body  5  is provided with one or more slots  122  in an upper region for interaction with corresponding parts of the fixing collar  3  as described below. 
     The detachable mouthpiece  20  is attached to the main body  5  by means of a bayonet fitting.  FIG. 15  shows the bayonet fitting as applied to a second embodiment of apparatus as will be described below. However, the mouthpiece fitting is equally applicable to the first embodiment. As shown in  FIGS. 2 and 15  the mouthpiece  20  is provided with an upstanding rim  120  in which are formed two opposed recesses  123  of roughly an L-shape configuration. The main body  5  comprises a circumferential recess  200  which receives the rim  120  when the two pieces are coupled together. At opposed points of the circumferential recess  200  the main body  5  is provided with retaining lugs  125  which pass along the recesses of the mouthpiece. Thus the mouthpiece may be coupled to the main body  5  by locating the lugs  125  relative to the upper end of the recesses and then twisting the main body  5  relative to the mouthpiece  20  whilst applying a compressive axial force to the two components. This results in the lugs  125  riding along the recesses resulting in the two components being firmly connected. Accordingly, it is very simple to change the mouthpiece of the dispensing apparatus, if desired or remove the mouthpiece for washing. The mouthpiece  20  is also provided with a spray block  14  for receipt of the axial protrusion  121 . The spray block  14  comprises a conduit having an upper end which receives the axial protrusion  121  and a lower end which comprises a spray outlet directed towards the outlet of the mouthpiece  20 . The spray outlet may be provided with a suitably dimensioned orifice or spray pattern block as known in the art to produce an atomised spray of product on dispensation. 
     The first number ring  11  is provided with two rows of angled abutment surfaces  41  located on two different diameter portions of that number ring as shown in  FIG. 9 . The angled abutment surfaces  41  of a larger diameter portion are indicated by reference  41   a  and those of a smaller diameter by reference  41   b , as shown in  FIG. 7 , in particular. The first number ring  11  comprises at least one notch  40  positioned on the outer edge thereof. The first number ring  11  is also provided with a set of numbering (not shown in the drawings) from 0 to 9 for each notch  40 , so that after the ninth actuation of the apparatus  1 , the notch  40  is in position to interact with the cog  12 . In a preferred embodiment, the number ring  11  will have three notches  40  and, so, will have three sets of numbering from 0 to 9. 
     The second number ring  13  is provided with an extended portion  150  which is positioned to enable covering of the markings on the first number ring  11  when a container locatable in the housing is empty. Advantageously, the extended portion  150  provides a clear indication to a user that the dispensing apparatus has provided its full-quota of dispensations. 
     The cog  12 , as shown in  FIG. 4  in particular, is provided with one or more teeth separated by a non-toothed spacer  160 . A first end  161  of the cog  12  includes four teeth  162  of reduced height and four teeth  164  of full height which in use interact with the first annular member  11 . The full height teeth  164  extend from the spacer  160  to the distal face of the first end  161  of the cog  12 . The teeth  50  at a second end of the cog  12  are all full height and these teeth in use interact with the second annular member  13 . The four teeth  162  having reduced height are, typically, half the height of the full height teeth  164 . Most preferably, the reduced height teeth  162  and full height teeth  164  are arranged alternately around the circumference of the cog  12 . 
     As shown in  FIGS. 2 and 5 , the sleeve  100  comprises an open-ended cylinder  170  having an upper end  171  which can receive the container  10  to be located in the dispensing apparatus  1  and a lower end  172  which has a reduced diameter opening  173  through which the valve stem  22  of the container  10 , located within the sleeve  100  may protrude from but through which the body of the container  10  cannot pass. The sleeve  100  is provided with two sets of formations on its exterior surface. The sets of formations are arranged diametrically opposite one another (only one set of formations is shown in  FIG. 5 ). Each set of formations comprises first, second and third formations. The first formation is provided at the lower end  172  in the form of longitudinally extending slots  114 . The slots  114  may be formed as a recess in the surface of the sleeve  100  or defined as the space between two parallel ridges formed on the sleeve  100 . The slots  114  extend from the lower end  172  to approximately the mid-point of the sleeve  100 . The second formation is provided above the slots  114  in the form of a projection  175  having upper and lower angled abutment surfaces  176 ,  177 . The third formation is provided at the upper end  171  in the form of a cantilevered projection  178 . The cantilevered projection  178  comprises an elongated portion having an angled abutment surface  179  on its lower, distal end. The elongated portion of the cantilevered projection  178  is axially aligned with the projection  175 . The elongated portion is joined to the cylindrical body of the sleeve  100  at a hinge point  181 . A void space  182  is formed around the elongated portion to accommodate movement of the cantilevered projection  178  in use as will be described below. 
     As shown in  FIG. 2 , the cap  2  fits over the upper end of the container  10 , opposite the metering valve. The cap  2  is provided with a plurality of external flange portions  130 , for interaction with the fixing collar  3 . 
     The fixing collar  3  is provided with one or more notches for locating in the one or more slots  122  of the main body  5 , so as to provide an improved push-fit attachment of the fixing collar  3  to the main body  5 . The fixing collar  3  is provided with internal flange portions  140 , such that, the external flange portions  130  of the cap  2  interact with the internal flange portions  140  to retain the cap  2  and, therefore, the container  10 , within the main body  5  when closed. The fixing collar  3  is provided with a clear portion  30 , or one or more apertures  30  through which portions provided with markings of the number rings  11 ,  13  are visible. Preferably, the fixing collar  3  is provided with a projection  124  at the end of which is provided the clear portion  30  or one or more apertures  30 . This projection  124  extends into the region of the main body  5  into a correspondingly-shaped hole  125 . This arrangement provides the clear portion  30  or the one or more apertures  30  at a position in the region of the main body  5  which allows viewing of the markings on the number rings  11 , 13 . 
     The fixing collar  3 , in combination with the cap  2 , provides a closure to the upper end of the main body  5 , remote from the mouthpiece  20 . In addition, the internal parts of the dispensing apparatus, for example, the number rings  11 ,  13 , the cog  12 , the sleeve  100 , and the container are held within the main body  5  by the fixing collar  3  and the cap  2 . 
     In use, a container  10  can be loaded into position within the apparatus  1  by separating the fixing collar  3  from the main body  5 . The pressurised dispensing container  10  is first inserted into the sleeve  100  and the cap  2  positioned on an upper end of the container  10 . The sleeve  100  is dimensioned so that the fit is a tight push-fit so that the container  10  is firmly retained in the sleeve  100 . The sleeve  100  and container  10  sub-assembly is then inserted, valve stem  22  first, into the opening of the main body  5 . The internal projections  110  of the main body  5  are received slidingly in the slots  114  of the sleeve  100  with the effect that the sleeve  100  is fixed rotationally relative to the main body  5 . The valve stem  22  of the pressurised dispensing container  10  is received in the axial protrusion  121 . Such loading inserts the sleeve  100  and dispensing container  10  through the central holes/apertures of the number rings  11 ,  13  and, when loaded, the number rings  11 , 13  are located around the container  10  as shown in  FIG. 2 . The fixing collar  3  is then fixed to the main body  5 . 
     The apparatus  1  is actuated by depression of the cap  2  which protrudes upwardly from the fixing collar  3 . Depression of the cap  2  causes the dispensing container  10  and sleeve  100  to move axially within the main body  5  to actuate the container  10 . Actuation causes an amount of product to be dispensed from the container  10  by an opposite reaction force from the constriction in the axial protrusion  121  acting on the valve stem  22 , which is inwardly retracted relative to the remainder of the metering valve such that an amount of product is dispensed from the valve stem  22  through the valve stem receiving block  14 , from where it is dispensed as an aerosol through the mouthpiece  20  and inhaled by a user inhaling on the mouthpiece  20 . Release of the cap  2  causes the cap  2  and the container  10  to return to its starting position, owing to the internal spring bias of the metering valve, ready for subsequent dispensing. 
     Each actuation of the apparatus  1  causes the first number ring  11  to rotate during the downstroke of the dispensing container owing to engagement of the angled abutment surface  179  of the cantilevered projection  178  with the angled abutment surfaces  41   a  the first number ring  11  and during the upstroke of the dispensing container owing to engagement of the angled abutment surfaces  176  if the projection  175  with the angled abutment surfaces  41   b  of the first number ring  11 . Both rotations are in the same sense such that over the actuation cycle of one downstroke and one upstroke the first number ring  11  rotates by one increment. Angled abutment surfaces  177  of the projection  175  ease passing of the projection  175  past the upper surfaces of the lower teeth of the first number ring  11 . Importantly, the force needed to rotate the first number ring  11  during a normal mode of operation is less than the force needed to flex the cantilevered projection  178  about the hinge point  181  sufficiently to allow the projection to bypass the teeth of the first number ring  11 . Thus, normally the number ring  11  rotates rather than the cantilevered projection  178  being flexed. 
     Every ten actuations of the apparatus  1  cause the notch  40  to pass the cog  12 , the effect of this being that one of the full height teeth  164  of the upper row of teeth is caught in the notch  40  as it rotates, this rotation causes a corresponding rotation of the cog  12  in the opposite sense. As a consequence, the second number ring  13  is caused to rotate in the same sense as the first number ring  11  by interaction of the teeth  50  on the bottom of the cog  12  and the teeth of the second number ring  13 . Therefore, it can be seen that every actuation of the apparatus causes the value of the numbering visible through the one or more apertures  30  to be decreased or augmented by a value of one. 
     If the number rings  11 ,  13  or cog  12  become jammed or otherwise inoperative the dispensing apparatus can still be actuated as follows. On engagement of the angled abutment surface  179  of the cantilevered projection  178  against the angled surfaces  41   a  of the first number ring (which are now immobile) the elongated portion of the cantilevered projection flexes about the hinge point  181  so that the distal end of the elongate portion moves out of alignment with the angled surfaces  41   a  of the teeth of the first number ring. The cantilevered projection and hence the sleeve  100  as a whole can now move axially downwardly into the actuated position with the elongated portion of the cantilevered projection passing between a pair of the teeth  41  of the first number ring  11 . 
     Another advantage of the use of the cantilevered projection  178  for incrementing the indexing mechanism is that it provides the dispensing apparatus with a mechanism for resisting sudden impacts. With some conventional mechanical dosage counters a problem can occur where the dispensing apparatus is dropped or otherwise suffers a sudden impact. This can cause damage to the indexing mechanism in particular damage to the relatively small teeth of the annular counter rings  11 ,  13 . Another potential problem of sudden impacts is that this can cause the indexing mechanism to increment or decrement because the indexing member is held, in the unactuated position, in close proximity or in contact with the indexing mechanism. In the present invention the use of the cantilevered projection  178  provides a degree of inherent flexibility in the indexing member which allows the indexing member to absorb sudden impulses of force such as occur when the device is dropped without leading to damage of the mechanism or the mechanism in the form of the annular members  11 ,  13  being incremented or decremented. For example if the dispensing apparatus is dropped so as to impact on a hard surface with the mouthpiece lowermost, the force impulse is transmitted upwardly through the main body  5  into the annular members  11 ,  13 . The force impulse is then transmitted from the annular members to the cantilevered projection  178 . However, at this point the cantilevered projection  178  is able to flex upwardly sufficiently to absorb the impulse without the effect that the upper annular member is damaged or rotated relative to the cantilevered projection. Thus, the inherent flexibility of the cantilevered projection  178  and the fact that a void space  182  is provided around it to accommodate movement of the cantilevered projection  178 , provides the dispensing apparatus with a mechanism for coping with impact forces without suffering damage or indexing the indexing mechanism. 
       FIGS. 8 to 14  illustrate a second embodiment of dispensing apparatus according to the present invention in which certain components have been modified. In the following description, only the parts that differ in structure or use are described in detail. Other parts which function in the same way as described in the first embodiment will not be described any further and reference is directed to the description of that embodiment. 
     As shown in  FIG. 8 , the apparatus  1  comprises a lower body  5  and an upper body  3  which may be transparent. A detachable mouthpiece  20  is again provided which is shown in  FIG. 15  and is described above. The first and second number rings  11 ,  13  and cog  12  are housed in the lower body  5  together with the sleeve  100 . The upper body  3  is open at its upper end and does not comprise a cap. The opening in the upper body  3  is sized such that the sleeve  100  cannot pass therethrough but so that the container  10  is able to pass through. 
     In the second embodiment, as shown in  FIGS. 9 and 13 , the sleeve  100  is modified. Firstly, the slots of the first embodiment are replaces by a pair of notches  114  in the lower end of the sleeve  100 . Secondly, the formation of the projection  175  of the first embodiment is replaced by a tension arm  300 . Preferably two tension arms  300  are provided at opposed points of the sleeve  100 . As with the projection  175  of the first embodiment, the tension arm  300  is located longitudinally between the notches  114  and the cantilevered projection  178 . The tension arm  300  comprises a cantilevered portion  301  which is fixed to the sleeve  100  at a hinge point  302 . Preferably, the tension arm  300  is provided in a single moulding as part of the sleeve  100  in which case the hinge point  302  marks the junction between the body of the sleeve  100  and the start of the cantilevered portion  301  of the tension arm  300 . A distal end  303  of the tension arm  300  is provided with an outwardly directed projection  304 . It can be seen from  FIG. 13  that the cantilevered tension arm  300  is able to accommodate flexure in a direction perpendicular to flexure of the cantilevered projection  178 . That is, the outwardly directed projections  304  of the tension arm  300  can flex substantially radially inwards when pressure is applied to the projections in a radially inward direction. It will be appreciated that the shape of the container  10  must accommodate inward flexure of the tension arms  300 . It is therefore preferable that the position of the tension arms  300  be located to coincide with the neck of the container  10  where it narrows to meet the ferrule of the metering valve, as shown in  FIG. 9 . It will therefore be apparent that the overall length of the sleeve  100  is less than in the first embodiment. Alternatively, the walls of the container  10  may have formed in them depressions to accommodate inward flexure of the tensions arms  300 . 
     As shown in  FIGS. 10 to 12 , the cog  12  is slightly adapted compared to the first embodiment. The spacer  160  is cylindrical. In addition, the cog  12  is provided with upper and lower axial projections  190  and  191  which allow the cog  12  to be rotationally mounted in recesses formed in the lower body  5  as shown in  FIG. 10 . 
       FIG. 14  illustrates first number ring  11  of the second embodiment. It will be seen that the number ring  11  differs from that in the first embodiment only to the degree that the lower set of angled abutment surfaces  41   b  formed on the smaller diameter portion of the ring are replaced by a series of inwardly directed projections  310  having a triangular cross-section when viewed from above. The projections  310  are arranged around the circumference of the lower portion of the ring  11  so as to form a series of interspersed peaks and troughs. Each projection  310  comprises two faces  311 ,  312  on either side of the peak. Preferably, the faces  311 ,  312  are arranged symmetrically about the peak. The faces  311  and  312  form angled abutment surfaces which engage the outward projection  304  of the tension arm  300  in use as will be described below. 
     In use, the internal components of the apparatus, such as the cog  12 , the sleeve  100  and the number rings  11 ,  13  can be loaded into position within the apparatus  1  by separating the upper body  3  from the lower body  5 . The sleeve  100  can be inserted, valve stem  22  first, into the opening of the lower body  5 . The internal projections  110  of the lower body  5  are received slidingly in the notches  114  of the sleeve  100 , as shown in  FIG. 9 , with the effect that the sleeve  100  is fixed rotationally relative to the lower body  5 . The valve stem  22  of the pressurised dispensing container  10  is received in the axial protrusion  121 . The sleeve  100  is arranged to pass through the central holes/apertures of the number rings  11 ,  13  and, when loaded, the number rings  11 , 13  are located around the container  10  as shown in  FIG. 9 . The collar  3  is then attached to the main body  5 . 
     The pressurised dispensing container  10  can now be passed through the hole in the upper body  3  to be received in the sleeve  100 . The internal face of the sleeve  100  is provided with a non-return feature  200 , shown schematically in  FIG. 16 . The non-return feature  200  is preferably in the form of a flexible flange  200  which protrudes inwardly and in a downwards direction. As the container  10  is inserted into the sleeve  10  the flange  200  is deflected outwardly to allow a ferrule  201  of the container  10  to pass. Once in the assembled position the flange  200  springs back outwardly to engage in an undercut formation formed between the ferrule  201  and the body of the container  10  as shown in  FIG. 16 . In this way removal of the container  10  from the sleeve  100  is prevented. 
     In the inserted position the upper end of the container  10  protrudes upwardly through the hole in the upper body  3 . Once assembled, the sleeve  100  passes within the first number ring  11  as in the first embodiment. The arrangement is shown in  FIG. 9 . 
     On actuation of the apparatus  1 , downward movement of the sleeve  100  relative to the first number ring  11  brings the angled abutment surface  179  of the cantilevered projection  178  into contact with the angled abutment surfaces  41   a  of the upper teeth of the first number ring  11  as described above in the first embodiment. Thus, as in the first embodiment, during the down stroke of the sleeve  100  the first number ring  11  is rotated a partial increment by interaction of the angled abutment surface  179  with the angled abutment surfaces  41   a  of the first number ring  11 . This partial rotation of the first number ring  11  causes each outwardly directed projection  304  of each tension arm  300  to ride up an angled face  311  of respective protrusions  310 . This movement is accommodated by the tension arms  300  as they flex radially inwards. The relative location of the angled abutment surfaces  41   a  and the projections  310  is such that when the down stroke of the sleeve  100  is completed the outwardly directed projections  304  of the tension arms  300  have ridden up the angled abutment surfaces  311  and over the peak of the projections  310  such that the outwardly directed projections  304  lie in contact with the angled abutment surfaces  312  of the projections  310 . Thus, when the container is released, and the sleeve  100  consequently moves back on its up stroke, the completion of the incremental rotation of the first number ring  11  is achieved by the biasing force of the outwardly directed projections  304  of the tension arms  300  on the angled abutment surfaces  312  as the tension arms  300  try to return to their unstressed position. This biasing force completes the rotation of the first number ring  11  such that the outwardly directed projections  304  of the tension arms  300  lie in the neighbouring trough between the projections  310  after one actuation. Consequently, the cantilevered projection  178  and the tension arm  300  (or the pairs of these features where present) act as first and second indexing members which together act to index the counter mechanism. 
     The indexing mechanism of the second embodiment has a particular advantage over the indexing mechanism of the first embodiment. The indexing mechanism of the second embodiment is better able to cope with the manufacturing tolerances of the components. In the first embodiment, in order to ensure that the indexing mechanism is incremented at the right point it is necessary to control the longitudinal position of the cantilevered projection  178  relative to the projection  175  as well as the relative longitudinal positions of the cantilevered projection  178  with the features of the axial protrusion  121  which receives the valve stem in use. Not only this it is necessary to control the longitudinal position of the projection  175  relative to the features of the axial protrusion  121 . In the second embodiment, the longitudinal position of the projections  310  is not a determinative, critical tolerance since the longitudinal location of the projections  310  does not affect operation of the indexing mechanism as long as the projections  310  extend upwardly and downwardly enough to remain in contact with the outwardly directed projections  304  of the tension arms  300  in use. Thus, by ensuring that the projections  310  have sufficient depth the specific longitudinal location of the outwardly directed projections  304  relative to the projections  310  in the unactuated position is not a critical tolerance. This may be seen by noting that the cantilevered projection  178  and the tension arm  300  act along different axes—the first longitudinally relative to the sleeve and the second radially to the sleeve. Thus the relative longitudinal position of these two features is not critical. This results in the manufacture of the device being significantly simplified. 
     Another advantage is that the container  10  and sleeve  100  may more easily return to the unactuated position when the container  10  is released compared to the first embodiment. In the first embodiment the internal spring bias of the metering valve must overcome the friction caused by contact between the projection  175  and the angled abutment surfaces  41   b  which is relatively high. In the second embodiment the degree of friction caused by contact between the outwardly directed protrusions  304  and the projections  310  is much less as the contact face is parallel to the direction of movement of the sleeve  100 . 
     The remainder of the operation of the apparatus, for example the manner in which the first number ring  11  interacts with the second number ring  13  is the same as in the first embodiment described above. 
     In the first embodiment it has been described that the apparatus comprises a cap  2  to close off an upper end of the apparatus. It will be appreciated that the presence of the cap  2  is not essential to the working of the apparatus. In particular, if removal of the container  10  is to be prevented then other mechanisms may be provided other than the cap  2  without departing from the scope of the present invention as indicated in the second embodiment. 
     It will be appreciated that since the second embodiment still retains the cantilevered projection  178  as part of the indexing mechanism then the advantages of impact resistance as described above in the first embodiment will apply equally to the second embodiment. 
     Whilst in the specific example details of the invention are discussed, it will of course be understood that minor variations in features are still considered to be covered by the same inventive concept. 
     In an alternative embodiment, the dispensing apparatus may comprise, say, three or more number rings: a first number ring for ‘units’, a second for ‘tens’ and a third for ‘hundreds’. Further cogs may be provided. Subsequent number rings for ‘thousands’ and so on may also be added. The second and subsequent number rings are rotated by an arrangement as described herein (by a cog rotated by a previous number ring), whereby ten incremental rotations of the previous number ring—as started originally on the ‘units’ number ring by actuation of the apparatus—causes an incremental rotation of the subsequent number ring. 
     The invention has been described by way of example with the indexing member moving relative to the indexing mechanism in order to achieve bypass in the event of jamming of the apparatus. The preferred option is that the indexing member moves by means of flexing or otherwise being distorted relative to its unloaded configuration. It will be appreciated that the indexing member may be designed to pivot about a hinge point rather than flex. For example the hinge point could be provided with a spring element, such as a torsion spring, to allow pivoting only when a load threshold indicative of a jammed apparatus is exceeded. Alternatively, the indexing member may be sprung and be enabled to retract in a sliding manner relative to the sleeve  100  or shift sideways relative to the direction of movement of the sleeve  100  to allow the sleeve to move when the apparatus is jammed. Again, the spring force of the biasing means may be chosen to allow movement of the indexing member relative to the sleeve only when a jammed condition occurs. 
     The indexing member has been illustrated as being flexible about a single pivot point  181 . However the indexing member may be designed to have two pivot points forming a parallelogram four-bar mechanism. The flexible portion of the indexing member make take a number of forms including an arcuate portion having a serpentine configuration. 
     Finally, it will be appreciated that the indexing mechanism may be designed to move or flex relative to the indexing member as an alternative solution. For example, the teeth of the first and/or second number rings  11 ,  13  may be designed to have a degree of inherent elasticity which would allow a rigid indexing member to bypass by displacing or distorting the teeth if a jammed condition was encountered.