Abstract:
A metered dispenser includes a housing including a reciprocable piston drive stem including an inlet opening at a first end thereof, a floating piston at a second end, and a passage between the first and second ends. An inlet valve is provided adjacent the first end for permitting entry of liquid product into the passage. A biased cocking mechanism is reciprocally disposed substantially within the housing. A biased loading mechanism is movable in a second generally opposite direction by the cocking mechanism, and is engageable with the piston drive stem to move the drive stem in the second direction. When the cocking mechanism is moved from an initial rest position toward the second direction, a series of operations allow the loading mechanism to project the drive stem in the first direction to dispense a metered dose of liquid product through a discharge orifice provided adjacent the second end.

Description:
BACKGROUND OF INVENTION  
       [0001]     a. Field of Invention  
         [0002]     The invention relates generally to liquid dispensers, and, more particularly, to a mechanically propelled metered dispenser for dispensing a predetermined quantity of liquid product.  
         [0003]     b. Description of Related Art  
         [0004]     Finger-powered dispensing pumps are known in the art, and generally include a finger operated pump head, which when depressed, discharges liquid product from a container having the pump mounted thereon. An exemplary finger-powered dispensing pump is disclosed in U.S. Pat. No. 3,414,169. Such pumps can be arranged as sprayers or atomizers in which a spray nozzle emits the pumped liquid as a spray, as shown in U.S. Pat. Nos. 3,194,447 and 4,433,799. Alternatively, the pumps can be arranged as liquid dispensers in which a dispensing nozzle thereof is a discharge spout, as shown in U.S. Pat. No. 3,216,625.  
         [0005]     It is desirable that means be provided for metering the amount of liquid dispensed, and also that such means be easy for a consumer to operate. For example, if the pump is used on a spray dispensing bottle for a hair spray, a consumer may desire a generally repeatable amount of spray dispensed per pump actuation. However, if the pump is used with a medicine dispensing bottle, it is desirable that the dispensed amount be repeatable and precise for imparting the intended effect.  
         [0006]     Such an exemplary metered dispenser for dispensing of medicine is disclosed in U.S. Pat. No. 5,613,957 to Py. Specifically, referring to  FIG. 1  of Py, there is disclosed an apparatus ( 10 ) for applying medicament and generally including an outer body ( 12 ), an inner body ( 14 ) and a piston body ( 16 ). When piston body ( 16 ) is located in the up position (see  FIG. 1 ), medicament is permitted to flow from medicament chamber ( 33 ), through slots ( 46 ), and drop cavity ( 38 ) to fill the drop cavity. When piston body ( 16 ) is pushed toward outer body ( 12 ) and into a down position, the downward stroke of piston ( 18 ) forces the medicament in drop cavity ( 38 ) through channel ( 44 ) and into interface ( 25 ). During this downward stroke of piston ( 18 ), flexible rim ( 40 ) is forced outwardly into contact with cylindrical wall ( 36 ), thus preventing the passage of medicament in drop cavity ( 38 ) back into medicament chamber ( 33 ). The pressurized medicament flowing through channel ( 44 ) opens interface ( 25 ) by forcing flexible outer nozzle portion ( 22 ) away from inner nozzle portion ( 24 ) to open the nozzle and release the medicament. Once the medicament is released, outer nozzle portion ( 22 ) returns to its normal position in contact with inner nozzle portion ( 24 ) so as to close interface ( 25 ).  
         [0007]     As readily evident from the afore-described operation of the Py metered dispenser, the dispenser requires piston body ( 16 ) to be pushed toward outer body ( 12 ) for dispensing of medicine through nozzle ( 20 ). When used adjacent an eye or a nostril for dispensing medicine, such a pushing action can lead to contact of the nozzle tip with a user&#39;s eye to contaminate the dispenser, and more importantly, can present a danger to the user&#39;s eye during repeated use if the nozzle tip indeed becomes contaminated. Yet further, since the amount of medicine dispensed is a function of piston body ( 16 ) which is pushed toward outer body ( 12 ), the amount of medicine dispensed can vary depending on whether a user completely pushes piston body ( 16 ) toward outer body ( 12 ), which can also be a function of a user&#39;s ability to push piston body ( 16 ) as required.  
         [0008]     It would therefore be of benefit to provide a metered dispenser which is repeatable in operation to dispense a predetermined dosage of medicine or other products, and which is usable by a broad range of users to repeatedly dispense a metered dosage of medicine without fluctuations in the amount of medicine dispensed. It would also be of benefit to provide a metered dispenser which is simple and economical to manufacture and assemble, and which is robust in design and efficient to operate.  
         [0009]     The following patents are representative of metered dispensers with feed-containing piston drive mechanisms:  
         [0010]     U.S. Pat. No. 3,754,687 to Robert W. Norton describes a pipetting dispenser of the piston-cylinder type with interchangeable fittings by which the operative movement of the piston may be arranged to be in line with or at an angle to the axis of an attached pipette and having adjustable stop means to limit travel of the piston within predetermined limits, together with means automatically retracting the piston from its discharge position to a position in engagement with said adjustable stop means, thereby insuring the repeated dispensing of the like volumes of liquid from said pipette in successive operations of the dispenser, for any adjusted position of the stop means.  
         [0011]     U.S. Pat. No. 3,934,585 to David M. Maurice discloses a method and apparatus for applying therapeutic eye drops to the eye by metering a predetermined volume of fluid and rapidly applying a pressure to one end of the metered fluid for forcing the fluid from a nozzle of means defining a small passageway such as and open-ended tube as a droplet having sufficient velocity to travel a generally horizontal distance in space to the eye. Unit dose application and multiple dose applications are included and provision is made for preventing anticipatory blinking of the eye during self-administration.  
         [0012]     U.S. Pat. No. 4,091,677 to Yuji Oshikubo describes a pipetting apparatus comprising a housing, a liquid receiving tube attached to the lower end of the housing and receiving a predetermined amount of a liquid sample herein, a cylinder piston device disposed in the housing for applying vacuum pressure on the upper end of the liquid receiving tube for sucking a liquid sample into the tube, a manually operable device for actuating the cylinder piston device, an air inlet for directing compressed air into the housing, and a manually operable valve for directing compressed air either to the upper end of the liquid receiving tube or to atmosphere.  
         [0013]     U.S. Pat. No. 5,226,895 to Dale C. Harris describes a present invention which relates to a hypodermic syringe having the same general appearance as a pen which is specifically adapted to provide for multiple measured injections of materials such as insulin or human growth hormone.  
         [0014]     U.S. Pat. No. 5,267,986 to Daniel Py describes and illustrates a cartridge for actuating a piston-like or accordion-like dispenser-vial for applying medication to any eye. The cartridge includes a housing for holding the dispenser-vial and a telescoping cylinder for compressing the dispenser-vial in the longitudinal direction to actuate the vial. The cartridge includes a locking mechanism for locking the telescoping cylinder to restrict its movement and a trigger mechanism for releasing the cylinder from the locked position so that a drop is released form the dispenser. The housing includes a finger for engaging the lower eyelid and exposing the conjunctival cul de sac.  
         [0015]     U.S. Pat. No. 5,401,259 to Daniel Py discloses a cartridge for actuating a piston-like or accordion-like dispenser-vial for a applying medicament to an eye. The cartridge includes a housing for holding the dispenser-vial and a telescoping cylinder for compressing the dispenser-vial in the longitudinal direction to activate the vial. The cartridge includes a locking mechanism for locking the telescoping cylinder to restrict its movement and a lever mechanism for releasing the cylinder from the locked position so that a drop is released from the dispenser. The housing includes a finger for engaging the lower eyelid and exposing the conjunctival cul-de-sac.  
         [0016]     U.S. Pat. No. 5,613,957 to Daniel Py discloses an apparatus used for applying medicament to an eye and to store the medicament in a medicament chamber. A nozzle is coupled in fluid communication with the medicament chamber and is formed by an outer nozzle portion and an inner nozzle portion received within the outer nozzle portion. A tight interface is defined between the inner nozzle portion and the outer nozzle portion and is normally in a closed position to prevent the passage of medicament through the nozzle. The interface opens in response to the flow of medicament of sufficient pressure into it to permit the passage of medicament through the nozzle for release into the eye.  
         [0017]     U.S. Pat. No. 5,685,869 to Daniel Py describes and illustrates an apparatus used to apply medicament to an eye and to store the medicament in a medicament chamber. A nozzle is couples in fluid communication with the medicament chamber and is formed by an outer nozzle portion and an inner nozzle portion received within the outer nozzle portion. A seam is formed by the interface of the inner nozzle portion and the outer nozzle portion and is normally in a closed position to prevent the passage of medicament through the nozzle. The seam opens in response to the flow of medicament or sufficient pressure into the seam to permit the passage of medicament through the nozzle for release into the eye.  
         [0018]     U.S. Pat. No. 6,413,246 B1 to John E. Harrold describes a present invention that relates to a metered, mechanically propelled, liquid dispenser. It has a main body cylinder having liquid and liquid advancing mechanism for advancing the liquid into a metered dosage dispensing chamber. There is a cocking mechanism which includes a lock pin, a stressed slot and rest slot. When the cocking mechanism is locked, the advancing means is moved and liquid is ready for firing from the metered dosage dispensing chamber through a dispensing orifice. The cocking mechanism is slowly rotated while holding the main body cylinder vertically and the pin is manually moved in the rest slot thereby causing a plunger to be forced by a spring to push against a stop on a trigger which advances the trigger to rapidly force the liquid out of the metered dosage dispensing chamber through the dispensing orifice. The dispensing orifice includes a one-way valve which allows the liquid to be dispensed while preventing air from returning to the device.  
         [0019]     U.S. Pat. No. 6,419,663 B2 to John E. Harrold describes a present invention mechanically propelled, liquid metered dispenser includes a main housing with liquid storage and a liquid advancing component for either allowing liquid to flow out or assisting in the flow of liquid out of the main housing by exerting pressure, into a metered dosage dispensing chamber in response to a loading movement of a cocking mechanism. The chamber has an inlet connected to the main housing with a one-way valve to only permit flow of liquid into the chamber. The chamber also has an outlet orifice for dispensing liquid therefrom in a metered amount. The chamber ahs a reciprocal plunger and has a load and release component connected to it, which includes a cocking mechanism, a locking mechanism, and a spring. The cocking mechanism is functionally connected to the plunger so as to move in harmony therewith, or, more preferably, to move a relatively, short distance relative to the distance traveled by the cocking mechanism.  
         [0020]     Notwithstanding the prior art, the present invention is neither taught nor rendered obvious thereby.  
       SUMMARY OF INVENTION  
       [0021]     The invention solves the problems and overcomes the drawbacks and deficiencies of prior art metered dispenser designs by providing a manually operable metered dispenser including a housing having a reciprocable piston drive stem including an inlet opening at a first end thereof, a floating piston disposed at a second end thereof, and a passage between the first and second ends. An inlet valve may be provided adjacent the first end for permitting entry of liquid product into the passage, and an outlet valve may be provided adjacent the second end. A cocking mechanism may be reciprocally disposed substantially within the housing, and may be biased in a first direction. A loading mechanism may be biased in the first direction, movable in a second generally opposite direction by the cocking mechanism, and engageable with the piston drive stem to move the piston drive stem in the second direction. The loading mechanism may be further engageable with one or more stops provided in the housing.  
         [0022]     For the metered dispenser described above, when the cocking mechanism is moved from an initial rest position toward the second direction, the cocking mechanism moves the loading mechanism and along therewith the piston drive stem in the second direction. Further, during movement of the loading mechanism in the second direction, the loading mechanism engages the stop, and during continued movement of the cocking mechanism in the second direction, the loading mechanism is disengaged from the stop to project in the first direction by the loading mechanism bias, and along therewith, project the piston drive stem in the first direction to dispense a metered dose of liquid product through a discharge orifice provided adjacent the second end.  
         [0023]     For the metered dispenser described above, the dispenser may be connectable to a pressurized or non-pressurized storage container having the housing formed integrally with the container. Alternatively, the dispenser may be connectable to a pressurized or non-pressurized storage container, and the housing may be formed separately from the container. The cocking mechanism may include a handle for permitting manual movement of the cocking mechanism toward the second direction. The inlet and outlet valves may be one-way valves for respectively permitting flow of liquid product into the passage and out through the discharge orifice. In an exemplary embodiment, the cocking mechanism may be biased by a first coil spring disposed substantially around the loading mechanism, and the loading mechanism may be biased by a second coil spring disposed substantially around the piston drive stem. In the noted exemplary embodiment, the first coil spring may have a diameter greater than the second coil spring.  
         [0024]     For the metered dispenser described above, the loading mechanism may include one or more substantially rigid arms including a catch element engageable with a shoulder on the piston drive stem for moving the piston drive stem in the second direction. The loading mechanism may include one or more legs including a catch element engageable with the stop to retain the loading mechanism in a loaded configuration during movement of the cocking mechanism from the initial rest position toward the second direction. The catch element of the legs may include a tapered surface engageable with a respective tapered surface on the stop to deflect the loading mechanism leg radially inwards and allow engagement of the loading mechanism catch element with the stop during movement of the cocking mechanism from the initial rest position toward the second direction.  
         [0025]     Yet further, for the metered dispenser described above, the cocking mechanism may include one or more legs including a release tab engageable with the catch element on the loading mechanism leg to disengage the loading mechanism from the stop during continued movement of the cocking mechanism in the second direction. The release tab may include a tapered surface for moving the catch element on the loading mechanism leg radially inwards to disengage the loading mechanism from the stop. The cocking mechanism may include one or more flexible arms including a finger engageable with the loading mechanism. The flexible arm may be deflected outwards during continued movement of the cocking mechanism in the second direction to release the loading mechanism from the cocking mechanism and allow the loading mechanism to project the piston drive stem toward the first direction.  
         [0026]     In a particular embodiment, the dispenser may be connectable to a pressurized or non-pressurized storage container including a sealed chamber defined by a container wall, an upper surface including the inlet valve and a lower surface including a spring biased piston for pressurizing liquid disposed within the chamber. The container may include a lower end having a removable container closure for retaining the spring biased piston. The container closure may include one or more release arms for retaining the spring biased piston in a first position. The release arm may further include a detent engageable by a piston plug insertable in an opening in the spring biased piston to release the spring biased piston from the first position for pressurizing liquid disposed within the chamber. When the cocking mechanism is moved from the initial rest position toward the second direction, the floating piston is allowed to move within an area at the second end to allow liquid product to enter from the passage into a metering chamber between the floating piston and the outlet valve for allowing the metered dose of liquid product to be dispensed through the discharge orifice when the piston drive stem is projected in the first direction.  
         [0027]     In alternative embodiments of the present invention, the dispenser may be connectable to a storage container including a sealed chamber defined by a container wall, an upper surface including the inlet valve and a lower surface including a floating piston. Alternatively, the dispenser may be connectable to a pressurized storage container including a sealed chamber defined by a container wall, an upper surface including the inlet valve and a lower surface including an externally threaded piston engageable with complementary internal threads in the container for pressurizing liquid disposed within the sealed chamber upon rotation of the piston.  
         [0028]     Further, for the metered dispenser described above, the container may include a circular or a rectangular profile. The cocking mechanism may be spring biased to return to the initial rest position. The dispenser may be usable for nasal and/or eye-care, and the metered dose may be dispensed as a spray or a fine mist.  
         [0029]     The invention further provides a manually operable metered dispenser including a housing having a reciprocable piston drive stem including an inlet opening at a first end thereof, a floating piston disposed at a second end thereof, and a passage between the first and second ends. An inlet valve may be provided adjacent the first end for permitting entry of liquid product into the passage, and an outlet valve may be provided adjacent the second end. A cocking means may be reciprocally disposed substantially within the housing, and may be biased in a first direction. A loading means may be biased in the first direction, movable in a second generally opposite direction by the cocking means, and engageable with the piston drive stem to move the piston drive stem in the second direction. The loading means may be further engageable with one or more stops provided in the housing.  
         [0030]     For the metered dispenser described above, when the cocking means is moved from an initial rest position toward the second direction, the cocking means moves the loading means and along therewith the piston drive stem in the second direction. Further, during movement of the loading means in the second direction, the loading means engages the stop, and during continued movement of the cocking means in the second direction, the loading means is disengaged from the stop to project in the first direction by the loading means bias, and along therewith, project the piston drive stem in the first direction to dispense a metered dose of liquid product through a discharge orifice provided adjacent the second end.  
         [0031]     For the metered dispenser described above, in an exemplary embodiment, the dispenser may be connectable to a pressurized or non-pressurized storage means having the housing formed integrally with the storage means. Alternatively, the dispenser may be connectable to a pressurized or non-pressurized storage means, and the housing may be formed separately from the storage means. The cocking means may include a handle for permitting manual movement of the cocking means toward the second direction. The inlet and outlet valves may be one-way valves for respectively permitting flow of pressurized liquid product into the passage and out through the discharge orifice. The cocking means may be biased by a first spring (which in an exemplary embodiment may be a coil spring) disposed substantially around the loading means, and the loading means may be biased by a second (which in an exemplary embodiment may also be a coil spring) spring disposed substantially around the piston drive stem. In the noted exemplary embodiment of the present invention, the first coil spring may have a diameter greater than the second coil spring.  
         [0032]     For the metered dispenser described above, the loading means may include one or more substantially rigid arms including a catch element engageable with a shoulder on the piston drive stem for moving the piston drive stem in the second direction. The loading means may include one or more legs including a catch element engageable with the stop to retain the loading means in a loaded configuration during movement of the cocking means from the initial rest position toward the second direction. The loading means catch element may include a tapered surface engageable with a respective tapered surface on the stop to deflect the loading means leg radially inwards and allow engagement of the loading means catch element with the stop during movement of the cocking means from the initial rest position toward the second direction.  
         [0033]     Yet further, for the metered dispenser described above, the cocking means may include one or more legs including a release tab engageable with the catch element on the loading means leg to disengage the loading means from the stop during continued movement of the cocking means in the second direction. The release tab may include a tapered surface for moving the catch element on the loading means leg radially inwards to disengage the loading means from the stop. The cocking means may include one or more flexible arms including a finger engageable with the loading means. The flexible arm may be deflected outwards during continued movement of the cocking means in the second direction to release the loading means from the cocking means and allow the loading means to project the piston drive stem toward the first direction.  
         [0034]     In a particular embodiment, the dispenser may be connectable to a pressurized storage means including a sealed chamber defined by a storage means wall, an upper surface including the inlet valve and a lower surface including a spring biased piston for pressurizing liquid disposed within the chamber. The storage means may include a lower end having a removable storage means closure for retaining the spring biased piston. The storage means closure may include one or more release arms for retaining the spring biased piston in a first position. The release arm may further include a detent engageable by a piston plug insertable in an opening in the spring biased piston to release the spring biased piston from the first position for pressurizing liquid disposed within the chamber. When the cocking means is moved from the initial rest position toward the second direction, the floating piston is allowed to move within an area at the second end to allow liquid product to enter from the passage into a metering chamber between the floating piston and the outlet valve for allowing the metered dose of liquid product to be dispensed through the discharge orifice when the piston drive stem is projected in the first direction.  
         [0035]     In alternative embodiments of the present invention, the dispenser may be connectable to a storage means including a sealed chamber defined by a storage means wall, an upper surface including the inlet valve and a lower surface including a floating piston. Alternatively, the dispenser may be connectable to a pressurized storage means including a sealed chamber defined by a storage means wall, an upper surface including the inlet valve and a lower surface including an externally threaded piston engageable with complementary internal threads in the storage means for pressurizing liquid disposed within the sealed chamber upon rotation of the piston.  
         [0036]     The invention also provides a manually operable metered dispenser including a housing including a reciprocable frame member having a push-button connected thereto at a first end. The frame member and the push-button may be biased in a first direction. An inlet valve may be provided adjacent a second end for permitting entry of liquid product into a metering chamber defined by a cavity in the frame member. When the push-button is moved from an initial rest position toward a second generally opposite direction against the bias, a volume of the metering chamber is reduced to allow discharge of a metered dose of liquid product through a discharge orifice of a nozzle connected to the housing.  
         [0037]     For the metered dispenser described above, the frame member may be integrally formed with the push-button. In a particular embodiment, the dispenser may be connectable to a pressurized storage container including a sealed chamber defined by a container wall. An upper surface may include the inlet valve and a lower surface may include a spring biased piston for pressurizing liquid disposed within the sealed chamber. The container may include a lower end having a removable container closure for retaining the spring biased piston. The container closure may include one or more release arms for retaining the spring biased piston in a first position. The release arm may further include a detent engageable by a piston plug insertable in an opening in the spring biased piston to release the spring biased piston from the first position for pressurizing liquid disposed within the sealed chamber. In a particular embodiment, the push-button may be spring biased in the first direction.  
         [0038]     In alternative embodiments of the present invention, the aforementioned metered dispenser may be connectable to a storage container including a sealed chamber defined by a container wall, an upper surface including the inlet valve and a lower surface including a floating piston. Alternatively, the dispenser may be connectable to a pressurized storage container including a sealed chamber defined by a container wall, an upper surface including the inlet valve and a lower surface including an externally threaded piston engageable with complementary internal threads in the container for pressurrizng liquid disposed within the sealed chamber upon rotation of the piston.  
         [0039]     Additional features, advantages, and embodiments of the invention may be set forth or apparent from consideration of the following detailed description, drawings, and claims. Moreover, it is to be understood that both the foregoing summary of the invention and the following detailed description are exemplary and intended to provide further explanation without limiting the scope of the invention as claimed. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0040]     The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate preferred embodiments of the invention and together with the detail description serve to explain the principles of the invention. In the drawings:  
         [0041]      FIG. 1  is an exploded view of an embodiment of a metered dispenser according to the present invention, illustrating various components of the metered dispenser and an exploded view of an exemplary pressurized container for mounting the dispenser;  
         [0042]      FIG. 2 ( a ) is a front sectional view of the metered dispenser of  FIG. 1 , illustrating the dispenser in an unloaded configuration, and mounted to the exemplary pressurized container of  FIG. 1 ;  
         [0043]      FIG. 2 ( b ) is a front sectional view of the metered dispenser of  FIG. 1 , illustrating the dispenser in an unloaded configuration, and mounted to the exemplary container with a floating piston of  FIG. 1 ;  
         [0044]      FIG. 3  is an enlarged partial front sectional view of the metered dispenser of  FIG. 1 , illustrating the dispenser in the unloaded configuration;  
         [0045]      FIG. 4  is a cross-sectional view of the metered dispenser of  FIG. 1 , taken substantially along line  4 - 4  in  FIG. 3 ;  
         [0046]      FIG. 5  is an enlarged partial front sectional view of the metered dispenser of  FIG. 1 , illustrating the dispenser in a loaded configuration;  
         [0047]      FIG. 6  is an enlarged partial front sectional view of the metered dispenser of  FIG. 1 , illustrating the dispenser just after being loaded and prior to being discharged;  
         [0048]      FIG. 7  is an enlarged partial front sectional view of the metered dispenser of  FIG. 1 , illustrating the dispenser in a discharge configuration after loading;  
         [0049]      FIG. 8  is an enlarged front sectional view of the metered dispenser of  FIG. 1 , illustrating the dispenser in an inverted configuration for injection of liquid product within the container;  
         [0050]      FIG. 9  is a front sectional view of another embodiment of a metered dispenser according to the present invention, illustrating the dispenser in an unloaded configuration;  
         [0051]      FIG. 10  is a bottom view of yet another embodiment of a metered dispenser according to the present invention, usable in conjunction with the embodiments of  FIGS. 1 and 9 ; and  
         [0052]      FIG. 11  is a front sectional view of another embodiment of a metered dispenser according to the present invention, illustrating the dispenser in an unloaded configuration. 
     
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS  
       [0053]     Referring now to the drawings wherein like reference numerals designate corresponding parts throughout the several views,  FIGS. 1-8  illustrate a mechanically propelled metered dispenser according to the present invention, generally designated “metered dispenser  10 .”  FIGS. 9-11 , respectively, illustrative further embodiments of the present invention.  
         [0054]     Referring to  FIGS. 1 and 2 ( a ), metered dispenser  10  may be generally mounted on a pressurized storage container  12  of the type illustrated in  FIGS. 1 and 2 ( a ), or another similar pressurized container known in the art, for dispensing, for example, medicinal liquid  14  or other products which required dispensing of a metered dosage. As shown in FIGS.  2 ( a ) and  3 , metered dispenser  10  may generally include an upper end  16  having a discharge orifice  18  and a lower end  20  having an inlet port  22 . Orifice  18  may be fluidly connected to inlet port  22  via passage  24  provided in piston drive stem  26 , and may be configured to dispense liquid product  14  in the form of a liquid stream or a fine mist. Piston drive stem  26  may be biased upwardly by means of first internal spring  28 , which engages a loading mechanism  30  to bias stem  26  upwards by means of the engagement of shoulders  32 ,  34  respectively provided on loading mechanism  30  and stem  26 . Loading mechanism  30  may further include at least two rigid arms  31  including catch elements  33  engageable with shoulder  34  of piston drive stem  26 . In the particular embodiment illustrated, four symmetrically disposed rigid arms  31  may be provided. Piston drive stem  26  may be guided at its lower end for vertical reciprocation within a stem guide  36  and define a receiving chamber  35  between the lower-most end of piston drive stem  26  and the adjacent surface of stem guide  36 .  
         [0055]     A cocking mechanism  38  including a handle  40  may be provided for actuating metered dispenser  10 . Cocking mechanism  38  may be disposed for reciprocation within dispenser housing  42  and include a plurality of flexible arms  44  engageable with upper surface  46  of loading mechanism  30 . In the particular embodiment illustrated, two flexible arms  44  may be provided. Further, housing  42  may be formed with container  12  as shown, or may be otherwise formed separately and attached to container  12  by adhesive, threadeadly or other means known in the art. In this manner, a completely separate metered dispenser  10  may be manufactured, assembled and thereafter attached to a variety of pressurized containers. Cocking mechanism  38  may further include at least two legs  48  including release tabs  50  which are engageable with catch elements  52  provided on legs  54  of loading mechanism  30 . In the particular embodiment illustrated, two legs  48  and  54  may be provided. A second internal spring  56  may bias cocking mechanism  38  upwards to the unloaded position illustrated in FIGS.  2 ( a ) and  3 . As shown in  FIG. 5 , spring  56  may engage a support  57  in housing  42  for retention thereof in the housing. As discussed below, at least two complementary stops  58  may be provided on dispenser housing  42  for engagement with catch elements  52 . Stops  58  may each include a tapered edge  60  engageable with complementary tapered edge  62  of catch elements  52  for deflecting elements  52  radially inwards as shown in  FIG. 6 , and discussed in greater detail below.  
         [0056]     Referring still to FIGS.  2 ( a ) and  3 , metered dispenser  10  may include a first one way inlet valve  64  held in place by an insert  66  disposed in lower portion  68  of stem guide  36 . Further, a second one way inlet valve  70  may be disposed in an insert  71  or in an area  72  formed at upper end  74  of hollow stem  76 . Stem  76  may include an integrally formed cap  77  which allows retention of the internal components of dispenser  10  on housing  42 . As shown in FIGS.  2 ( a )- 4 , valves  64 ,  70  may each include a lower flexible portion  78  including a plurality of slits  80  for permitting flow of liquid  14  from container  12  into passage  24  when dispenser  10  is disposed in the unloaded configuration of  FIG. 1 . Further, valves  64 ,  70  may each include an upper rigid portion  82  which engages upper surface  84  of insert  66  or the upper surface of insert  71  to effectively prevent flow of liquid product from passage  24  back to container  12 .  
         [0057]     As shown in FIGS.  2 ( a ) and  3 , a floating valve piston  86  may be provided in upper cavity  88  of piston drive stem  26 . Piston  86  may be retained within cavity  88  by means of a circular ring  90  on drive stem  26  engageable with detent  92  on piston  86 .  
         [0058]     Referring next to  FIGS. 1 and 2 ( a ), for the exemplary pressurized storage container  12  illustrated, container  12  may generally include an outer shell  94  having an upper surface  96  onto which housing  42  can be formed with shell  94  or otherwise threadeadly or adhesively mounted to enable attachment of dispenser  10 . An inner piston  98  may be disposable within outer shell  94  and include a central opening  100  for permitting container  12  to be filled with liquid product  14 . Central opening  100  may include a circular catch  102  at a bottom area thereof, with catch  102  being engageable with circular detent  104  provided on release arm  106  of container closure  108 . A piston plug  110  may be sealingly insertable into central opening  100  for sealing chamber  112  within container  12 . Piston plug  110  may include a circular catch  114  engageable with the bottom of catch  102 , and be sized for a friction fit within opening  100 . A spring  116  may be provided within inner piston  98  for biasing piston  98  upwards as illustrated in  FIG. 1 .  
         [0059]     Referring to  FIG. 8 , container  12  is illustrated prior to being filled with liquid product  14 . As illustrated, in order to fill container  12  with liquid product and pressurize the container by means of inner piston  98 , piston  98  may first be disposed within outer shell  94 , such that ring  118  on release arm  106  is engaged with circular catch  102  to hold piston  98  in the position shown. With spring  116  disposed as shown within piston  98 , container closure  108  may be slid onto outer shell  94  to retain inner piston  98  and spring  116  within shell  94 . With container  12  inverted, liquid product  14  may then be injected into container  12  through central opening  100 . With container  12  still in an inverted configuration, piston plug  110  may be inserted into central opening  100  to seal chamber  112 . Alternatively, instead of injecting liquid into container  12  through central opening  100 , the liquid may be placed in container  12  in the inverted configuration illustrated, and container closure  108  having piston  98  attached as a unit may be slid onto the outer shell  94  of container  12  to achieve the same results. This would of course provide a larger area for injection of liquid into container  12 . As piston plug  110  is inserted, circular catch  114  on the bottom of piston plug  110  may contact circular detent  104  to deflect release arm  106  outwardly and thus release inner piston  98  within shell  94 . In this manner, as the volume of liquid product  14  within chamber  112  is reduced, inner piston  98 , which has piston plug  110  sealingly inserted therein, is biased upwards by means of spring  116  to pressurize chamber  112 .  
         [0060]     According to an alternative embodiment shown in  FIG. 2 ( b ), dispenser  10  may be attached to a container with a floating piston. In this embodiment, piston drive stem  26 , when moving in the direction of bias of spring  28 , may suck liquid product  14  from container  12  through inlet port  22  into passage  24 . The amount of liquid suctioned may be determined by the size of receiving chamber  35  as well as the stroke parameters of piston drive stem  26 .  
         [0061]     Referring next to  FIGS. 3 and 5 - 7 , metered dispenser  10  is respectively illustrated in unloaded, loaded, prior to discharge and discharge configurations. The operation of metered dispenser  10  will therefore be described in detail with reference to FIGS.  2 ( a )- 7 .  
         [0062]     Specifically, as illustrated in FIGS.  2 ( a ) and  3 , metered dispenser  10  is illustrated in an unloaded configuration, with springs  28  and  56  disposed in their fully extended positions. In the unloaded configuration of FIGS.  2 ( a ) and  3 , inner piston  98  having piston plug  110  sealingly disposed therein may pressurize chamber  112  to force liquid product into passage  24  via first one way inlet valve  64 . Additionally, valve seat  87  of piston drive stem  26  may push floating valve piston  86  upwards so that upper area  89  of piston  86  contacts upper valve seat  91  to effectively close passage  24 . In order to discharge product  14  out through discharge orifice  18 , a user may grasp container  12  having metered dispenser  10  mounted thereon in the palm of their hand and with the fore and middle fingers contacting handle  40 , the user may pull handle  40  downwards.  
         [0063]     As handle  40  is being pulled downwards to the loaded position of  FIG. 5 , flexible arms  44  of cocking mechanism  38  pull loading mechanism  30  downwards until catch elements  33  on arms  31  contact the upper surface of shoulder  34 . At this position, catch elements  33  prevent loading mechanism  30  from being moved further downwards. Further, from the transition of handle  40  from the  FIG. 3  to the  FIG. 5  position, tapered edges  62  of catch elements  52  contact tapered edges  60  of stops  58  to deflect legs  54  radially inwards until catch elements  52  snap under stops  58  as shown in  FIG. 5 . Additionally, the contact between piston  86  and valve seat  87  is released to allow piston  86  to “float” within area  93 , and thus simultaneously allow liquid product  14  present in passage  24  to enter into metering chamber  95 .  
         [0064]     Referring to  FIGS. 5 and 6 , as handle  40  is pulled further downwards, the frictional contact between edges  122  of fingers  124  of flexible arms  44  is overcome to allow arms  44  to spread apart and thus allow further downward movement of cocking mechanism  38 . During the further downward movement of cocking mechanism  38 , tapered edges  126  of release tabs  50  on legs  48  contact edge  128  of catch elements  52  to deflect legs  54  radially inwards to release catch elements  52  from under stops  58  as shown in  FIG. 6 .  
         [0065]     Referring to  FIGS. 6 and 7 , upon release of catch elements  52  from under stops  58 , piston drive stem  26  is projected upwards with piston  86  under the bias of spring  28 , such that valve seat  87  which is disposed in contact with piston  86  projects piston  86  upwards and thus reduces the volume of metering chamber  95  to discharge liquid product through discharge orifice  18  as shown. In this manner, a precisely metered amount of liquid product present in metering chamber  95  is discharged through discharge orifice  18 . Once the upper area  89  of piston  86  contacts valve seat  91  and the lower area  93  of piston  86  contacts valve seat  87 , further flow of liquid product into metered chamber  95  is shut off. In a particular embodiment of the present invention, metering chamber  95  may be sized to discharge approximately 50-140 micro-liter of product through discharge orifice  18  for nasal usage, and may be otherwise sized to discharge approximately 15-25 micro-liter of product for eye-care usage.  
         [0066]     Referring to FIGS.  2 ( a ),  3  and  7 , in order to reset metered dispenser  10  for further actuation, handle  40  may be released to the position of  FIG. 2 ( a ), whereby a user may simply pull handle  40  as discussed above with reference to FIGS.  2 ( a ),  3  and  5 - 7  to actuate and dispense additional metered doses of liquid product through discharge orifice  18 .  
         [0067]     Referring next to  FIG. 9 , another embodiment of the invention will now be described in detail, with this embodiment being generally referred to as “metered dispenser  200 .” 
         [0068]     Specifically, as shown in  FIG. 9 , metered dispenser  200  may generally include the dispenser being mounted on a pressurized storage container, and in the particular embodiment illustrated, dispenser  200  may be mounted on a container  12  similar to the container illustrated in  FIG. 2 ( a ). Metered dispenser  200  may generally include a housing  202  including a horizontally extending nozzle  204  having a tapered discharge passage  206 . A spring biased push-button  208  may be reciprocally mounted on housing  202 , with a spring  210  disposed within the housing as shown for biasing push-button  208 . Push-button  208  may be mounted on a reciprocal frame  212 , which together with internal frame  214 , defines a metering chamber  216 . In the particular embodiment illustrated, internal frame  214  may be formed with container  12 , but as with metered dispenser  10 , the components of dispenser  200  may be formed separately, assembled as a unit, and thereafter attached to a variety of pressurized containers. A one-way inlet valve  218 , similar to valve  64  for metered dispenser  10  may be mounted by insert  220  to permit pressurized liquid product  14  to enter into chamber  216 .  
         [0069]     In operation, in order to dispense liquid product through the outlet orifice of nozzle  204 , a user may grasp container  12  having dispenser  200  mounted thereon. By using a thumb, the user may press push-button  208  downwards so that pressurized product present in metering chamber  216  is expelled out through the outlet orifice of nozzle  204 . During pressing of push-button  208 , one-way inlet valve  218  may seal metering chamber  216  to prevent return of liquid product present in chamber  216  into container  12 . Further, upon release of push-button  208 , spring  210  may bias push-button  208  upwards, and during this movement of push-button  208 , additional liquid product may enter into metering chamber  216  by means of the pressure created by inner piston  98 , as discussed above.  
         [0070]     Referring next to FIGS.  2 ( a ) and  10 , another pressurized storage container  250  will now be described in detail.  
         [0071]     Specifically, as shown in  FIG. 10 , compared to container  12 , container  250  may include a generally rectangular profile. In this regard, container  250  may include a rectangular inner piston  252  into which a rectangular piston plug  254  is disposed and allows for the release of piston  252  by means of engagement with circular detent  256  provided on release arm  258 , in a similar manner as circular detent  104  provided on release arm  106  for the embodiment of  FIG. 2 ( a ). As apparent to those skilled in the art, a metered dispenser  10  or  200  may be mounted to container  250  in a similar manner as discussed above for container  12 .  
         [0072]     Referring next to FIGS.  2 ( a ) and  11 , another pressurized storage container  300  will now be described in detail.  
         [0073]     Specifically, as shown in  FIG. 11 , compared to container  12 , container  300  may be internally threaded at  302  for complementary engagement with an externally threaded piston  304 . In order to pressurize the liquid within container  300 , piston  304  may be rotated as needed for movement towards the dispenser, and for thereby dispensing of the pressurized liquid in the manner discussed above.  
         [0074]     To summarize, the present invention thus provides a metered dispenser which is repeatable in operation to dispense a predetermined dosage of medicine or other product, and is usable by a broad range of users to repeatedly dispense a metered dosage of medicine without fluctuations in the amount of medicine dispensed, or without the dispenser being readily susceptible to contamination during use.  
         [0075]     Although particular embodiments of the invention have been described in detail herein with reference to the accompanying drawings, it is to be understood that the invention is not limited to those particular embodiments, and that various changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the invention as defined in the appended claims.  
       INDEX OF REFERENCE NUMBERS  
       [0000]    
       
           10  . . . metered dispenser  
           12  . . . pressurized storage container  
           14  . . . liquid  
           16  . . . upper end  
           18  . . . discharge orifice  
           20  . . . lower end  
           22  . . . inlet port  
           24  . . . passage  
           26  . . . piston drive stem  
           28  . . . first internal spring  
           30  . . . loading mechanism  
           31  . . . rigid arm  
           32  . . . shoulder  
           33  . . . catch element  
           34  . . . shoulder  
           35  . . . receiving chamber  
           36  . . . stem guide  
           38  . . . cocking mechanism  
           40  . . . handle  
           42  . . . dispenser housing  
           44  . . . flexible arms  
           46  . . . upper surface  
           48  . . . legs  
           50  . . . release tabs  
           52  . . . catch elements  
           54  . . . legs  
           56  . . . second internal spring  
           57  . . . support  
           58  . . . complementary stops  
           60  . . . tapered edge  
           62  . . . tapered edge  
           64  . . . first one way inlet valve  
           66  . . . insert  
           68  . . . lower portion  
           70  . . . second one way inlet valve  
           72  . . . area  
           74  . . . upper end  
           76  . . . hollow stem  
           77  . . . cap  
           78  . . . lower flexible portion  
           80  . . . slits  
           82  . . . upper rigid portion  
           84  . . . upper surface  
           86  . . . floating valve piston  
           87  . . . valve seat  
           88  . . . upper cavity  
           89  . . . upper area  
           90  . . . circular ring  
           91  . . . valve seat  
           92  . . . detent  
           93  . . . area  
           94  . . . outer shell  
           95  . . . metering chamber  
           96  . . . upper surface  
           98  . . . inner piston  
           100  . . . central opening  
           102  . . . circular catch  
           104  . . . circular detent  
           106  . . . release arm  
           108  . . . container closure  
           110  . . . piston plug  
           112  . . . sealing chamber  
           114  . . . circular catch  
           116  . . . spring  
           118  . . . ring  
           122  . . . edges  
           124  . . . fingers  
           126  . . . tapered edges  
           128  . . . edge  
           200  . . . metered dispenser  
           202  . . . housing  
           204  . . . horizontally extending nozzle  
           206  . . . tapered discharge passage  
           208  . . . push-button  
           210  . . . spring  
           212  . . . reciprocal frame  
           214  . . . internal frame  
           216  . . . metering chamber  
           218  . . . one-way inlet valve  
           220  . . . insert  
           250  . . . pressurized storage container  
           252  . . . rectangular inner piston  
           254  . . . rectangular piston plug  
           256  . . . circular detent  
           258  . . . release arm