US3789843A - Breath-actuated aerosol dispenser - Google Patents

Abstract

An inhalation device for use with an aerosol container capable of discharging a metered amount of an aerosol formulation on depression of its valve nozzle comprising, a chamber, a mouthpiece communicating with the chamber, a mechanism for causing actuation of the valve including a movable wall, a linking lever, an actuating lever, a spring biasing the actuating lever, and a latch mechanism such that the movable wall member disposed between an air admission port into said chamber and said mouthpiece moves away from said port under influence of air flow through said port to release the latch mechanism when suction is applied to said mouthpiece and therefore causing the actuating lever to actuate the valve.

Description

United States Patent Armstrong et a1. Feb. 5, 1974 [54] BREATH-ACTUATED AEROSOL 3,456,646 7/1969 Phillips 128/173 R DISPENSER [75] Inventors: John C. Armstrong, Milton; George Prima'y Examiner-Richard Gaudet F. Lyman, Weston, both of Mass. W" f 'i 75 9 7) Recla Attorney, Agent, or Firm-Robert E. Meyer, Dike, [73] Assignee: Armstrong-Krupp Development Bronstein Roberts & Cushman Corporation, West Roxbury, Mass. V V [22] Filed: Feb. 23, 1972 [57] ABSTRACT [21] Appl. No.: 228,529 An inhalation device for use with an aerosol container capable of discharging a metered amount of an aerosol formulation on depression of its valve nozzle com- [301 Forelgn Apphcanml Data prising, a chamber, a mouthpiece communicating with Feb. 25, Great Bntaln hamber, a mechanism for causing actuation of the valve including a movable wall, a linking lever, an [52] US. Cl. 128/173 actuating lever a spring biasing the actuating lever ::-:--.:;.--1::::---;Al and a latch mechanism such that the movable wall [58] F|e1,d ofSearch.. ..l28/173,208,213, 222, member i d between an air admission port i 13/1722 272; 46 M said chamber and said mouthpiece moves away from said port under influence of air flow through said port [56] References C'ted to release the latch mechanism when suction is ap- UNITED STATES PATENTS plied to said mouthpiece and therefore causing the ac- 3,456,645 7/1969 Brock 128/173 R mating lever t tuat the valve. 3,636,949 8 1969K 128 173 R ropp 5 Claims, 13 Drawing Flgures5a I 54 55 42 94 2s 7 '31 3 93 l 56 j M Q I ifI 42 a i 35 b 24I 34e1 44 1; J 5 25 T i I L 1| 41 mm a e 64 -66 5-68 K r PATENTEDFEB 5 1914 SHEET 1 BF 7 FIG. 1

PATENTEU FEB 5 I974 SHEEI 2 BF 7 FIG. 3

PATENTEDFEB mm 3.789.843

SHEET 7 0F 7 I36 FIG. IO

BREATH-ACTUATED AEROSOL DISPENSER BRIEF SUMMARY OF THE INVENTION This invention relates to an inhalation-actuated aerosol dispenser of the type disclosed and claimed in Kropp US. Pat. No. 3,636,949, dated Jan. 25, 1972.

Aerosol pharmaceuticals still constitute a relatively minor unit volume in the aerosol field. In the period from 1950 to 1960, there was considerable enthusiasm about the future growth of aerosol pharmaceuticals, but by the early l960s, it was apparent that the market for aerosol pharmaceuticals had not developed as some had predicted.

Much of the early optimism about this future market size developed as a result of the potential for inhalation aerosols, especially bronchodilators. This was based on the enormous advantage that the modern aerosol package brought into inhalation therapy, in contrast to the earlier crude nebulizers.

These advantages are:

1. Uniform dosage with metering valves;

2. Uniform particle size of the medicinal preparation;

3. Greatly improved product stability and elimination of outside contamination by virtue of the hermetically sealed aerosol;

4. Inexpensive, compact dispensing containers. in contrast to orally delivered medication, inhalation aerosols have these outstanding advantages:

1. Infinitely more rapid relief through absorption in the bronchi and pulmonary areas. In this respect, aerosol inhalation can often be considered equivalent to injection;

2. Lower dosage levels of medicament are possible due to its delivery to the site of the broncho-spasm. This is usually due to the absence of loss in the intestinal tract;

3. Elimination of gastro-intestinal side effects. With these advantages generated by aerosol technology, the early optimism is not surprising.

Aerosol inhalation therapy, however, at least in the United States, has failed to meet the expected growth pattern. Perhaps the drug industry has needed a decade to become aerosol oriented and accept this new delivery system before expanding into new opportunities involving inhalation aerosols.

The most significant problem associated with inhalation aerosols has been the difficulty for many patients to coordinate the manual release of the medication with the initiation of inspiratory effort. Indeed, many people not afflicted with asthma, bronchitis, emphysema, or other respiratory difficulties have demonstrated that they are unable to coordinate these tasks properly. Patients suffering from the distress of broncho-restriction may have much greater difficulty. In addition, synchronization is difficult for both children and elderly patients. These are two important groups who could benefit from aerosol bronchodilators if coordination were not a problem.

A second and related problem lies in the fact that even though the aerosol metering valve delivers a predetermined dosage of aerosol medicament time it is depressed, the valve can be depressed repeatedly. Thus, if the patient's coordination with his breathing is off and the desired relief is not obtained, he has a tendency to press the valve again and again. This possibility of an unintentional excess dosage delivered to the region of the mouth and upper throat rather than to the bronchi and pulmonary areas as desired has somewhat restricted the range of medicaments packaged in aerosol form.

Very recently, these problems have been alleviated with the development of breath-actuated aerosol dispensing devices such as the one disclosed in the aforesaid Kropp patent. Sometimes these are referred to as inhalation-initiated aerosols or more simply demand valves. Very simply, the demand valve eliminates the need for manual coordination by actuating automatically when the patient inhales with his lips in contact with a mouthpiece. Only a very slight negative pressure is required to trip the simple mechanism which actuates the metering valve. In addition the demand valve must be reset before the metering valve may be discharged again. One of the important features of this development is that it in no way changes the dosage or packaging components previously in use insofar as the refill aerosol is concerned. The same metering valve, container body (glass, metal or plastic), medicament, and propellant system may be used. No changes are required in the filling and packaging lines with the exception of final assembly and the insertion of the demand valve itself. The unit is easy to use and compact.

One such device is described and claimed in the aforesaid patent. This comprises a walled chamber provided with a mouthpiece and with an air access port remote from the mouthpiece. The air access port is at least substantially filled with a movable wall portion designed to move toward the interior of the chamber when air is removed from the chamber through the mouthpiece as by a person inhaling with the mouthpiece in his mouth. Means are provided to retain an aerosol container in a fixed position with the metering valve of the aerosol container located within the chamber in a position to discharge aerosol compound through the mouthpiece. The actuating mechanism consists of the movable wall portion; a linking lever having a latch means, which lever is pivotally mounted in the chamber to move about its pivot responsive to the movement of the wall portion; an actuating lever with a catch means adapted to cooperate with the latch means on the linking lever pivotally mounted in the chamber, said actuating lever having a portion adapted to press against the metering valve of the aerosol container and spring means to bias said wall portion and said linking lever toward an initial portion wherein the latch means of the linking lever may engage the catch means of the actuating member and to move the actuating lever toward pressing engagement with the metering valve. Finally, there is a resetting means such as a strap associated with the actuating mechanism passing to the outside of the chamber adapted when pulled to move the actuating lever against the force of the spring away from engaging contact with the metering valve and to bring the catch of the actuating lever into contact with the latch of the linking lever and an air valve means associated with the actuating mechanism adapted to admit outside air freely from a position remote from the mouthpiece relative to the metering valve when the actuating mechanism is triggered.

The operation is very simple. To cock the device one pulls on the resetting means. This pulls the actuating lever away from the metering valve to a position where the latch of the actuating lever can engage the catch of the linking lever. At the same time the movable wall 3 portion is biased toward an initial position pivoting the linking lever so that its latch may engage the catch. When the latch and the catch are engaged the device is cocked.

To trigger the device all one need do is to place the mouthpiece in his mouth and inhale. Upon reduction of pressure within the chamber the movable wall-portion moves inwardly. This rotates the linking lever about its pivot removing the catch from engagement with the latch of the actuating lever. As soon as this happens the spring moves the actuating lever into contact with the metering valve which in turn discharges the metered amountof aerosol compound through the mouthpiece. Simultaneously the air valve is opened admitting a scavenging flow of air into'the chamber from a position behind the metering valve relative to the mouthpiece permitting the person to complete his inhalation cycle freely and completely. At the same time, since the rush of air comes in behind the metered aerosol discharge of medicament, forces that medicament into the bronchi and pulmonary areas as is desired.

The device described in the aforesaid Kropp patent has proven to be a very practical, useful, effective and relatively inexpensive device. However, a number of changes have been made during the course of the development toward commercialization of this device,as a result of extensive testing, without, however, any substantial change in the essential mechanism as described above.

DETAILED DESCRIPTION OF THE DRAWINGS FIG. 1 is'an elevation partially in section of a first version of the improved device of the present invention at the moment of actuation taken alongline 11 of FIG.

FIG. 2 is an elevation partially in section corresponding to FIG. 1 but with the device in its cocked and locked position; v I

FIG. 3 is a top view of the device of FIGS. 1 and 2;

- FIG. 4 is a section alongline 44 of FIG. 1;

FIG. 5 is a rear view of the device of FIGS. 1 and 2;

FIG. 6 is an elevation partially in section of a second version of the improved device in its cocked and locked position;

FIG- 7 is an elevation in section of the device of FIG. 6 at the moment of actuation; I

FIG. 8 is a front view of the device of FIGS. 6 and 7;

FIG. 9 is'a rear view of the device of FIGS. 6 and 7;

FIG. 10 is a top view of the device of FIGS. 6 and 7;

FIG. 11 is a section along line 1l11 of FIG. 6;

FIG. 12 is a detail of the leaf spring and linking lever of the device of FIGS. 6 and 7; and

FIG. 13 is a partial elevation showing a second ver-' sion of the sliding cover.

DETAILED DESCRIPTION than. but substantially the same size as, a pack of kingsize cigarettes. molded from a rigid thermoplastic material such as high-impact polystyrene, in two symmetrical halves indicated at 22 and 23.joined together. De-

mand valve 21 is provided with afront wall portion 24,

arear wall portion 25, aright side 26, aleft side 27, a top 28, and a bottom 29. A forwardly extendingportion 31 near the bottom offront'wall portion 24 together with a corresponding extension at the bottom ofright side 26,left side 27 and bottom 29, forms amouthpiece 32 with a substantiallyrectangular aperture 33 of convenient size to be held between a persons lips. Aninternal wall 34 having a generally vertical portion -35 and ahorizontal portion 36 divides the interior ofdemand valve 21 into two chambers, an aerosol-receivingchamber 37 and an operatingchamber 38.Internal wall 34 is continuous except foraperture 39 provided inhorizontal portion 36 at the bottom of aerosol container-receivingchamber 37 to receive thevalve nozzle portion 39 of anaerosol container 43 within operatingchamber 38.Rear wall portion 25 is provided with a plurality of horizontal air-admitting apertures orports 41, which when themouthpiece 32 is held'in a persons mouth provides the only important access for entry of air into operatingchamber 38.Walls 24, 34 and portions ofwalls 28 and 29 are provided with an internal groove in left half 32 (the half shown in FIGS. 1 and 2) and a corresponding tongue inright half 23, to facilitate the matching of the two halves and to provide an airlock along the line of juncture. Y

A standard medicament aerosol container is indicated at 43. Such containers are provided in glass, metal or plastic (a typical glass container is shown) and while there are some minor structural differences between the three,,all three are made to a standard size and all conventionally have acontainer body 44 with aneck portion 45, acap 46, acylindrical extension 47 oncap 46, avalve stem 48 and anozzle 49.Nozzle portion 49 is generally rectangular in cross-section with flat parallel sides. The standard such container is designed to be operated in the inverted or valve-down position and to expell upon pressure a measured amount of a mixture of propellant and medicament horizontally fromnozzle 49 eachtime nozzle 49 is pressed towardcontainer 44. Aerosolcontainer-receivingchamber 37 is of asize to receive thestandard aerosol container 43 with the shoulder ofcap 46 resting against the top ofhorizontal wall portion 36 and withcylindrical extension 47,valve stem 48, andnozzle portion 49 extending into operatingchamber 38 throughaperture 39 withoutlet 50 ofnozzle portion 49 adjacent to and substantially at the center ofmouthpiece aperture 33. Guidingslots 52 and 53 are provided on the inside ofside walls 26 and 27, both to insure the proper entry ofcontainer 43 intochamber 37 and to minimize the width ofdemand valve 21.

Chamber 37 is provided with acover portion 54 pivotally mounted as indicated at 55 at one end between the side walls at a point adjacentinternal wall 34. The other end ofcover.portion 54 is provided with a forwardly extendingfinger grip 56 which extends through a recess provided therefor at the top of .front wall 24. At each side of grip 56 a series of interlocking ridges, indicated at 57, are provided both on the forward end ofcover 54 and the inside offront wall 24, to retaincover 54 in place. The bottom ofcover 54 is provided with anupstanding bead 58 adapted to press against the bottom ofcontainer 43. Withcover 54 raisedcontainer 43 can easilybe introduced into or removed from container-receivingchamber 37. Whencover 54 is locked into position by interlockingridges 57 by pressure on its top,container 43 is retained inchamber 37.

The actuating mechanism is substantially identical to that disclosed and claimed in the aforesaid US. Pat.

No. 3,636,949, and comprises amovable wall portion 61, a linkinglever 62, an actuatinglever 63 and aspring 64. Such modifications as have been made were made for ease and reliability of manufacture, and ease and reliability of assembly, It will be noted as explained below that there are only five parts other than the twoshell halves 22 and 23; that there are no sub-assemblies except to link one end ofspring 64 to actuatinglever 63, and all of the parts except forspring 64, the other end of which is slipped over apost 80 provided therefor between the two shell halves, are pivotally mounted between opposed sockets provided in the two shell halves, so that the entire assembly can be put together very rapidly and very easily.

Movable wall portion 61 is a flat plate that substantially fills all of the interior space insiderear wall 25. It is pivotally mounted at the bottom by a pair ofstuds 65, one of which is provided on each side and each of which is adapted to fit into asocket 70 provided therefor inside walls 26 and 27. A raisedportion 66 is provided on the interior side thereof to provide a bearing surface for one end of linkinglever 62.

Linkinglever 62 is provided at an intermediate portion with a pair ofopposed studs 67 adapted to fit into sockets (not shown) provided therefor on the inner walls ofsides 26 and 27 to act when assembled as a pivot. A centrally disposedelongated arm portion 68 is provided abovestuds 67 and a relativelyshort blade portion 69 is provided belowstuds 67.Arm portion 68 is provided on one side at its end with arounded knob portion 71 adapted to ride against raisedportion 66 ofmovable wall 61. The lower end ofblade portion 69 is provided with aflat surface 72 which acts as the catch.Surface 72 is tapered slightly so that the edge closest to actuatinglever 63 is slightly closer tostud 67 than is the edge away from the actuatinglever 63. The back ofarm portion 68 is provided with a rounded raisedportion 73 at a position slightly abovepivot 62 adapted to rest againstspring 64 and thereby to biasknob 71 and correspondinglymovable wall 61 towardrear wall 25.

Actuatinglever 63, resettingstrap 74 and mouthpiece cover 75 are injection molded as a one-piece assembly. Actuatinglever 63 is provided at one end with a pair ofopposed studs 76 adapted to fit into a pair of sockets (not shown) provided therefor on the inside ofside walls 26 and 27 to provide a pivot mounting. The body oflever 63 is formed as an inverted saddle with twoside walls 77 adapted whendemand valve 21 is assembled andaerosol container 43 is in place therein, to overlie closely on each side the flat sides ofnozzle portion 49.Side walls 77 are connected bybottom wall 78.Bottom wall 78 is formed,adjacent pivot 76, in an inverted V-shape providing on the top thereof a relativelysharp edge 79 adapted to press against the end ofnozzle 49. At a point remote frompivot 76 beyond the location ofnozzle 49, there is provided aweb portion 81 betweenside walls 77 of actuatinglever 63. Beyondweb portion 81, abottom wall 78 is thickened slightly as a strengthening measure and terminates in a generallycylindrical portion 82 which is separated fromside walls 77 and is adapted to receive a loop at one end ofcoil spring 64. The loop at the other end ofspring 64 passes around mountingpost 80 provided betweenside walls 26 and 27adjacent top 28. The arrangement of the parts is such that the side ofspring 64 presses against roundedportion 73 of linkinglever 62 as the demand valve is being cocked to biasmovable wall portion 61 towardrear wall 25.

Side walls 77 of actuatinglever 63 extend beyond the location ofspring 64 passing therebetween and anotch 83 is provided at the intersection of the top of eachside wall 77 with that end of eachside wall 77 remote from pivots 76. The two aforesaid notches are adapted to engagesurface 72 ofblade portion 69 of linkinglever 62 to act as a latch.

Resettingstrap 74 extends fromcylindrical portion 82 beyond the location of the end of thespring 64 through aslot 84 provided therefor inbottom wall 29. Agroove 85 is provided on the bottom or back side ofstrap 74 at a position adjacent the outside ofbottom wall 29 when the device is in its cocked position to act as a bend line.Strap 74 terminates in mouthpiece cover portion adapted to coveraperture 33 ofmouthpiece 32. A second groove or thinnedportion 86 is provided at the intersection ofstrap 74 andcover portion 75 also to act as a bend line. The length of 74 is such that whencover portion 75 is in place overmouthpiece 32 the latch of actuatinglever 63 is slightly removed from the catch of linkinglever 62 as shown in FIG. 2 so that no movement ofmovable wall 61, while the device is in the storage position can uncock the device. The release ofcover 75 frommouthpiece 32 permits the catch to re-engage the latch under the force ofspring 64 placing the device in condition for instant use.

The upper end ofcover portion 75 is provided with aninward extension 87 having a groove 88 adapted to engage aridge 89 provided on the upper outer end ofupper wall 31 ofmouthpiece 32. Aridge 91 is provided across a midpoint on the inside ofcover piece 75 of an extent substantially equal to the width ofaperture 33 to insure thatcover 75 will covermouthpiece 32 when in position.

As pointed out above the release ofcover 75 frommouthpiece 32 permits the catch and latch to engage and further permits the mouthpiece to be placed in a persons mouth as indicated in FIG. 1. Upon the inhalation by that person the pressure is reduced within operatingchamber 38 creating a pressure differential between the side ofmovable wall portion 61adjacent airadmitting ports 41 inrear wall 25 and theside facing chamber 38. As soon as the pressure differential is sufficient to overcome the biasing force imposed upon linkinglever 62 by contact between the side ofspring 64 and roundedportion 73 on the rear of linkinglever 62,movable wall portion 61 pivots aboutpivot 65 causing the linkinglever 62 to pivot about pivots 67, releasing the latch at the lower end of linkinglever 62 from the catch at the outer end of actuatinglever 63. As soon as this happensspring 64 is permitted to retract, forcingsharp edge 79 onbottom 78 of actuatinglever 63 against the end ofnozzle 49 ofaerosol container 43, causingaerosol container 43 to discharge a metered discharge throughaperture 53 ofmouthpiece 32 into the mouth of the person. The instant of discharge is shown in FIG. 1.

Valve means for admitting outside air into operatingchamber 38 at the instant of discharge to eliminate the reduced pressure withinchamber 38 permitting the person to complete his inhalation cycle and acting as a scavenger to force the discharge deep into the bronchi and pulmonary regions is provided by providing the upper portion of theside walls 26 and 27 with a pair ofrecesses 92 and 93, which recesses extend acrosstop wall 28 as indicated at 94 at a position behind the location ofmovable wall portion 61 when in its cocked position next torear wall 25 as in FIG. 2 but at the position assumed by the upper end ofmovable wall portion 61 between discharge as shown in FIG. 1.

Sincemovable wall portion 61 substantially fills the cross-section of operatingchamber 38 when the wall portion is in its cocked position adjacentrear wall 25, very little air is admitted intochamber 38 during the initial part of the persons inhalation cycle. It has been determined that some air leakage intochamber 38 is desirable since this prevents the device from being actuated by a mere sucking action and requires that there be an actual inhalation into the lungs. In addition either this leakage or the fact that the movable wall portion is pivotally mounted at one end or both increases both the sensitivity and the reproducibility of operation of the device. As soon as the device triggersmovable wall portion 61 pivots to a position where it is surrounded at its upper end byrecesses 92, 93 and 94 which in the actual device measure about l /z, l /zand 1 in. long respectively by one-sixteenth in. in depth. This additional opening of one-fourth square inch is approximately the same in area as the aperture shown in the embodiments shown in US. Pat. No. 3,636,949 and therefore permits the instantaneous ingress of approximately an equal amount of outside air.

The device is reset by pulling onstrap 74, which pulls down actuatinglever 63 against the force ofspring 64 permitting the catch of linkinglever 62 to engage the latch of actuatinglever 63. At the same time contact betweenspring 64 and roundedportion 73 of linkinglever 62 biases themovable wall portion 61 towardrear wall 25.

The embodiment ofdemand valve 21 shown in FIGS. 1 to 5 has been subjected to a very extensive testing program under field conditions. As a result of this testing a number of refinements were made, resulting in the embodiment shown in FIGS. 6 to 13 wherein as to most of the parts which remain unchanged the same numbers are assigned as in FIGS. 1 to 5.

Referring to FIGS. 6 to 13, the overall shape ofdemand valve 21 has been modified slightly to conform better to the shape of the hand. Thus since the width of the hand at the location of the little finger is less than the width of the hand at the location of the first three fingers, the bottom ofrear wall 25 has been rounded in slightly withmovable wall 61 shaped to conform. So alsoside walls 26 and 27 have been rounded in correspondingly adjacent their intersection withbottom portion 29. In addition the forward ends ofside walls 26 and 27 have been rounded in adjacent their junction withfront wall 24 to better conform to the typical shape of a bent thumb. As pointed out above, these changes in shape makedemand valve 21 easier and more comfortable to hold as well as making the overall appearance aesthetically more pleasing.

As far asrear wall 25 is concerned, it was discovered on field testing that there were two deficiencies. One was that the plurality of air-admittingports 41 tended to pick up dust, dirt and lint from the inside of pockets and pocketbooks, and provided to be difficult to clean. In addition there were a number of people who felt the need of a panic buttonsomething that they could push to trigger the device, if, for example, they were in the midst of an asthma attack. As a result, it was decided to provide a singleround aperture 101 as the airadmitting port. Amatching button 102 is provided on the face ofmovable wall portion 61.Button 102 is provided with an upstandingperipheral wall portion 103 designed to fit closely againstshoulder 104 provided around the periphery ofaperture 101.Button 102 is provided with a depressedcentral panel 105 in order to avoid the possibility that the device could be triggered inadvertently because of accidental contact between the side of a finger andbutton 102. The close contact betweenshoulder 104 ofaperture 101 and theperipheral wall portion 103 effectively keeps dirt out of space betweenmovable wall portion 61 and the inner sides ofrear wall 25. The area ofaperture 101 is such (the diameter is about eleven-sixteenth inch) that upon a slight reduction of pressure within operatingchamber 38wall portion 103 moves slightly away fromshoulder 104 admitting outside air to the entire back side ofmovable wall portion 61.

One unexpected development was that there turned out to be a wide variation in the force required to actuate various metering valves. This variation is not very critical when such valves are actuated manually since a persons thumb can develop a substantial amount of force. It becomes quite critical, however, when the force is applied by a spring attached to a lever arm since if the designed force applied is insufficient, it can be increased only by increasing the mechanical ratio of the lever arm or increasing the strength of the spring. A change in the ratio of the lever arm is impractical since this because of space limitations would require a complete redesign of the entire demand valve housing. On the other hand, a change in the strength of the spring necessarily changes the biasing force of the spring against linkinglever 62, thereby changing the actuating pressure differential. Of course the desired actuating pressure differential could be re-established by changing the internal geometry either by moving the location of mountingpost 80 or by changing the shape of rounded raisedportion 73 on linkinglever 62, or both. On the other hand, it was deemed undesirable to provide all of thedemand valves 21 with a spring of increased strength merely to accommodate that small percentage of metering valves which require an excessively high operating pressure, or in the alternative, to provide a number of different models of the demand valve differing only in the location of mountingpost 80 and/or the shape of linkinglever 62.

It was decided therefore to eliminate raisedportion 73 from the back of linkinglever 62 and to re-locate mountingpost 80 so thatspring 64 would at all times be free of contact with linkinglever 62. At the same time aseparate biasing spring 107 was provided tobias linking lever 62 and correspondinglymovable wall portion 61 toward the cocked position. This is shown in detail in FIG. 12.Spring 107 is provided with a generallyrectangular slot 108 arranged axially internally thereof in the upper portion for the passage ofelongated arm portion 68 of linkinglever 62 therethrough. Anotch 109 is provided on the front face ofelongated arm portion 68 to receive the upper end ofspring 107.Leaf spring 107, which is substantially of the same width asblade portion 69, extends around elongatedarm portion 68 behindpivot studs 67 and terminates in front of a mountingstud 110 provided therefor betweensides 25 and 26 just in front of and above pivots 65. An additional advantage of the separation of the actuating function ofspring 64 from the biasing function is that as soon as the internal pressure within operatingchamber 38 returns to normal after the actuation ofdemand valve 21movable wall portion 61 returns to its normal position in contact with the inner side ofrear wall portion 25 under the influence of biasingspring 107 as indicated in FIG. 7.

Another problem that developed was that it was possible to insertaerosol container 43 so thatoutlet 50 ofnozzle portion 49 was facing in the wrong direction so that upon actuation the discharge was directed toward the interior of operatingchamber 38 rather than throughmouthpiece 32 as described. This possibility has been eliminated by providing the rear ofnozzle portion 49 with anoutstanding boss 112 andaperture 39 with a corresponding slot 113. Ifboss 112 is aligned with slot 113 ascontainer 43 is inserted intobottlereceiving chamber 37,nozzle portion 49 will pass into operatingchamber 38 as desired. Unless the boss and the slot are aligned,container 43 cannot be inserted completely into bottle-receivingchamber 37.

There have been a number of design changes in actuatinglever 63.Side walls 77 have been extended to more completely surround the sides ofnozzle portion 49. Thesharp edge 79 on the inside of bottom 78 has been replaced by arounded portion 115 to provide a better bearing surface againstnozzle 49. The details of the mounting ofintegral strap 74 and of the lower end ofspring 64 have been changed for increased strength.Strap 74 now extends the full width of bottom 78 and the lower end ofspring 64 is now mounted in ametal pin 116 that passes between apertures provided for that purpose inside walls 77 in the portion behindweb 81. Reinforcingmembers 117 may be provided on the inside ofside walls 77 to further reinforce and strengthenpin 116 andside walls 77.

While the volume of air admitted throughairadmission ports 92, 93 and 94 was sufficient, there was some who believed that there was an advantage in admitting outside air into operatingchamber 38 upon the triggering ofdemand valve 71 from a position just behindnozzle 49. Accordingly in the embodiment shown in FIGS. 6 to 13 the air-admission port has been reestablished as anaperture 121 inbottom wall 29, which aperture is closed off when the device is in its cocked position byresilient foam pad 122 formed of a material such as a closed-cell neoprene foam adhesively mounted tobottom 78 of actuatinglever 63.Aperture 121 is substantially square-shaped with a dimension of about one-fourth inch more or less on each side.

Finally the design ofcover portion 54 was such that it proved difficult to manufacture in that its proper operation depended upon the maintenance of precise dimensions in three separately molded parts-cover portion 54,right half 22 and lefthalf 23. If the distance between the effective center ofpivot 55 and interlockedridges 57 incover portion 54 increases relative with the corresponding distances in the shell ofdemand valve 21, the cover becomes difficult to press into position. On the other hand, if this distance incover portion 54 decreases relative to the corresponding distance in the shell, the cover wont lock at all. In any event, the interlockingridges 57 tend to wear down with use. All in all the arrangement proved to be intolerant of normal manufacturing tolerances.

In place thereof a slidingcover 125 has been provided that extends over the entire top ofdemand valve 21. To accomplish thisside walls 26 and 27 andfront wall 24 are extended abovetop wall 28 and ahorizontal groove 126 is provided on the inside thereof to receivetongue 127 oncover 125. Adepressed panel 128 is provided on the top and near the rear of cover to act as a finger grip. The underside ofcover 125 is provided with a slidingwedge 129 designed to wedge against the top ofaerosol container 43 to hold it in place withcap 46 pressed againstinternal wall 36. Slidingwedge 129 has atransverse web portion 131 designed to ride ingroove 126 beneathcover 125, a dependingwedge portion 132 that tapers rearwardly downwardly and anupstanding boss 133 adapted to ride in agroove 134 provided axially therefor in the underside ofcover 125. In one version the top oftongue 133 and the bottom ofgroove 134 are provided with interlocking V-shapednotches 135. In this version asecond groove 136 is provided on the underside ofcover 125 to engageknob 137 provided on top ofweb 131 of slidingwedge portion 129. This knob and second groove limits the travel ofwedge portion 129 relative to cover 125.

Rear wall portion 25 is provided with aportion 138 which extends abovetop wall 28 sufficiently to permit clearance betweentop wall 28 and the bottom of slidingwedge 129 and to act as an abutment for the rear of slidingwedge 129 while permittingcover 125 to pass. Thus ascover 125 is slid back, the rear ofwedge 129 is forced againstabutment 138 which pusheswedge 129 toward the forward edge ofcover 125 where its further movement is prevented bygrooves 134 and 136 preventing further movement ofcover 125 as soon as bottle-receivingchamber 37 is completely opened. After aerosolcontainer 43 has been pressed into position in bottle-receivingchamber 37,cover 125 is pushed forward. Initially, as the forward end ofwedge 132 starts to slide up on the bottom ofcontainer 43,wedge portion 129 is relatively free to slide backward relative to slidingcover 125. Aswedge 129 continues to slide forward overcontainer 43 the resistance to movement because of the interaction of notches increases sufficiently to lockwedge 129 relative to coverplate 125. Further movement ofcover plate 125 forces thecontainer 43 into position in bottle-receivingchamber 37. Aridge 139 of minor width is provided on the bottom of slidingcover 125 in a position to engage the inside ofabutment 138 to holdcover 125 in its closed position.

This arrangement works very well in the case of metal aerosol containers where tolerances can be maintained carefully and the overall distance between the outside ofcase 46 and the bottom ofaerosol container 43 varies but a few thousandths of an inch at the most. In the case of glass containers where the variation may be as much as one-eighth inch i some degree of jamming sometimes results. In such instances a second version of the sliding wedge is preferred.

In this second version, shown in FIG. 13,notches 135 are entirely removed permittingboss 133 to slide freely ingroove 134.Wedge portion 139 is urged forwardly by aspring 141 mounted between the rear ofwedge 132 andabutment 138. A rearwardly extendinglug 142 may be provided onwedge 142 to support one end ofspring 141.

We claim:

1. An inhalation device for use with an aerosol container capable of discharging a metered amount of an aerosol formulation on depression of its valve nozzle,

said device comprising a chamber, a mouthpiece communicating with said chamber, spring means for causing actuation of said valve, latch means for maintaining the device in a cocked position ready for discharge, and triggering means responsive to suction applied to said mouthpiece, said triggering means including a movable wall member pivotally mounted internally of said chamber between an air-admission port means into said chamber and said mouthpiece, said movable wall member adapted to move away from said port means under the influence of ambient air pressure applied to one side of said wall through said port means when suction is applied to said chamber through said mouthpiece and by so moving to release said latch means, wherein said air-admission port means comprises an aperture in a wall of said chamber and said movable wall means includes a button means substantially filling said aperture when the device is in its cocked position.

2. An inhalation device as claimed in claim 1 wherein the clearance between the sides of said movable wall portion and the walls of said chamber is substantially less when the device is in its cocked position than when in its discharge position.

3. An inhalation device as claimed in claim 1 wherein said spring means biases said movable wall member toward said port when the device is in its cocked position.

4. An inhalation device as claimed in claim 1 wherein separate biasing spring means are provided to bias said movable wall member toward said port means when the device is in its cocked position.

5. An inhalation device as claimed in claim 1 wherein said device includes a second chamber for receiving and retaining said aerosol container and said device is provided with a sliding cover for said second chamber, said cover including a wedge member movable relative thereto, said wedge member adapted to press against the end of said container to retain said container in a fixed position in said second chamber when said cover is closed.

Claims (5)

1. An inhalation deVice for use with an aerosol container capable of discharging a metered amount of an aerosol formulation on depression of its valve nozzle, said device comprising a chamber, a mouthpiece communicating with said chamber, spring means for causing actuation of said valve, latch means for maintaining the device in a cocked position ready for discharge, and triggering means responsive to suction applied to said mouthpiece, said triggering means including a movable wall member pivotally mounted internally of said chamber between an airadmission port means into said chamber and said mouthpiece, said movable wall member adapted to move away from said port means under the influence of ambient air pressure applied to one side of said wall through said port means when suction is applied to said chamber through said mouthpiece and by so moving to release said latch means, wherein said air-admission port means comprises an aperture in a wall of said chamber and said movable wall means includes a button means substantially filling said aperture when the device is in its cocked position.

2. An inhalation device as claimed in claim 1 wherein the clearance between the sides of said movable wall portion and the walls of said chamber is substantially less when the device is in its cocked position than when in its discharge position.

3. An inhalation device as claimed in claim 1 wherein said spring means biases said movable wall member toward said port when the device is in its cocked position.

4. An inhalation device as claimed in claim 1 wherein separate biasing spring means are provided to bias said movable wall member toward said port means when the device is in its cocked position.

5. An inhalation device as claimed in claim 1 wherein said device includes a second chamber for receiving and retaining said aerosol container and said device is provided with a sliding cover for said second chamber, said cover including a wedge member movable relative thereto, said wedge member adapted to press against the end of said container to retain said container in a fixed position in said second chamber when said cover is closed.

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