Abstract:
A pressurized dispensing container for dispensing fluid products contains a valve stem which engages a resilient annular restoring boot to assure that the valve is returned to its closed state once manual force is removed from the valve. A valve stem shoulder engages the upper end of the restoring boot. To avoid having the boot snap around the shoulder and thus fail to restore the valve to its closed state when required, the following design feature is employed. The upper end of the annular boot has an inwardly facing flange which engages an annular recess or groove in the valve stem which recess is at a position directly below the valve shoulder. Certain dimensional relationships are optimum to provide assurance of full engagement between the inwardly facing boot flange and stem recess.

Description:
REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a continuation-in-part of Ser. No. 11/842,632 filed 21 Aug. 2007 and Ser. No. 11/842,640 filed 21 Aug. 2007; which applications in turn are continuations-in-part of Ser. No. 11/334,716 filed 18 Jan. 2006, which in turn is a continuation-in-part of Ser. No. 10/882,625 filed 30 Jun. 2004, which in turn is a continuation of Ser. No. 10/816,969 filed 2 Apr. 2004, now abandoned, and which in turn is a continuation of Ser. No. 10/285,238 filed 31 Oct. 2002, now abandoned; the entire disclosures of which are hereby incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     This invention relates to a valve for use in dispensing product from a pressurized container and more particularly to a valve with a design that minimizes the risk of a particular type of valve failure.  
         [0003]     The particular type of valve failure to which this invention is addressed is one involving the relationship between the resilient boot that restores a valve to the closed state when pressure is removed and the valve stem which engages the boot. The problem that arises is that, particularly in smaller valves, the upper rim around the boot snaps over the stem shoulder against which it abuts when the vertical pressure on the boot exceeds a threshold peculiar to the boot.  
         [0004]     The seriousness of this problem is inversely proportion to the size of the valve and more directly proportional to the pressure which has to be exerted to open the valve and to hold it open.  
         [0005]     Applicant&#39;s U.S. Pat. No. 5,785,301 and U.S. Pat. No. 6,425,503 and U.S. Pat. No. 6,340,103 are representative of prior valve designs for use in hand held pressurized containers dispensing a variety of products.  
         [0006]     The valve designs to which this invention is addressed have a sealing grommet which surrounds the valve stem. When the valve is closed, the lower portion of the sealing grommet encases the product openings in the valve stem and prevents product from being dispensed. The upper portion of the grommet is a thin wall boot portion whose upper edge engages a shoulder that extends out from the stem. When the stem is depressed to open the valve, the shoulder pushes down on the boot causing the boot to buckle. The boot, being resilient, therefore exerts a restoring force on the stem shoulder and thus on the stem to return the valve to its closed state once actuating pressure is removed from the valve stem.  
         [0007]     There are times when the pressure exerted by the valve shoulder on the resilient boot to open the valve causes the boot to snap around the shoulder, thus losing the restoring force and making the valve ineffective.  
         [0008]     The major purpose of this invention is to provide a valve design that minimizes the risk of this failure of engagement between boot and valve stem shoulder.  
         [0009]     It is a further and related purpose of this invention to meet the above objective in a design which minimizes the additional cost of fabricating the valve so as to make this improved valve economically viable or attractive in a wide range of pressurized dispensing containers.  
         [0010]     It is a further related purpose of this invention to provide such an improvement such that present manufacturing and assembly processes can readily be adapted to assembling the valve.  
       BRIEF DESCRIPTION  
       [0011]     This invention involves the provision of a radially inwardly extending annular flange at the upper edge of the boot and a mating annular recess on the stem. Since the upper edge of the boot abuts the stem shoulder, this annular recess on the stem has to be adjacent to and below the stem shoulder.  
         [0012]     It is important that the edge flange on the grommet will be fully inserted in the recess on stem wall. To assure this full engagement, it is desirable that the inner diameter of the boot below the flange essentially equal the outer diameter of the stem below the recess. A slip fit relationship would be preferable in most cases.  
         [0013]     This valve has been designed and tested and is shown to minimize or entirely avoid valve failure due to the boot snapping over the shoulder.  
         [0014]     It is believed that the key reason why the design is effective is that the downwardly facing surface of the stem which engages the upwardly facing surface of the boot is by this design extended radially inward. Accordingly, the net force exerted on the boot is brought radially inward. This relationship provides a greater surface over which stem to boot contact is maintained and appears to favorably affect the resolution of forces which otherwise tend to pull the upper edge of the boot out and around the engaging shoulder.  
       DEFINITIONS  
       [0000]     Nominal Clearance  
         [0015]     This term is used to refer to structural relations where the design values or target values of engaging structures are selected in part with an eye to the expected manufacturing tolerances and in part to prevent bonding of the boot flange on the stem recess.  
         [0016]     For example, the depth of the stem recess being slightly greater than the length of the boot flange coupled with the thickness of the inner end of the stem recess being slightly greater than the thickness of the end of the boot flange. In one embodiment, the stem recess design value is 15 mils and the boot flange length design value is 14 mils. In that embodiment, the design values are that at the innermost area of the stem recess. The width is 24 mils and at the end of the boot flange, the thickness is 20 mils.  
         [0017]     These nominal clearance relations assure that, when manufacturing tolerances are taken into account, there will be room for the flange to fit fully within the recess in both closed and open valve states.  
         [0018]     The above examples are for a given embodiment. The amount of the nominal clearances will be a function of experience with particular materials, manufacturing machines and the size of the valve.  
         [0000]     Up and Down; Lower and Upper  
         [0019]     The terms up and down as well as relational terms lower and upper are used to refer to the relations when a container having a valve is sitting on the shelf. In use, the container is usually tilted or upside down when used. It should be understood that these terms are used to provide easier description and refer to the valve when on a container sitting on a shelf.  
     
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0020]      FIG. 1  is a schematic view, in partial longitudinal sectional view of the valve of this invention in a closed state.  FIG. 1  shows the stem shoulder  32  engaging the upper edge of the boot  26  and also shows the boot flange and stem recess engagement.  
         [0021]      FIG. 2  is a schematic view, similar to that of  FIG. 1 , except that it shows the valve in an open state, that is in a product dispensing, state.  FIG. 2A  shows an alternate valve stem opening  22   a.    
         [0022]      FIG. 3  is an elevational view of the movable valve element which is also called the stem. It includes the button  18  and shoulder  32 .  FIG. 3  shows the annular recess  38  below the shoulder, which recess engages the boot flange  36 .  
         [0023]      FIG. 4  is a longitudinal sectional view of the grommet in its relaxed state showing the inwardly facing annular boot flange  36  at the upper edge of the boot  26 . This is the flange that engages the annular recess  38  in the stem.  
         [0024]      FIG. 5  is a larger scale view of the boot flange  36  and stem recess  38 . It is an exploded view to best show the relationship between the flange and recess.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0025]     The FIGs. illustrate a single embodiment. As shown in  FIG. 1 , the valve is a three piece valve assembly. It is constituted by a mounting cup  10 , a movable valve element  12  and a resilient annular sealing grommet  14 . The movable valve element  12  is also referred to as a valve stem  12 .  
         [0026]     In  FIGS. 1 and 2 , a finger operated actuator  16  is used to move the valve from a  FIG. 1  closed state to its  FIG. 2  open state. In the open state, product is dispensed because of the pressure within the container to which the valve is mounted.  
         [0027]     A lower portion of stem  12  has a button  18  which fits into a recess  20  in the grommet  14 . The valve stem has two openings  22  (one of which is shown) through which product is dispensed when the valve is open. When the valve is in the closed position shown in  FIG. 1 , the button  18  abuts against a surface  24  of the grommet  14  thereby effectively sealing the contents of the container from access to the valve openings  22 . When the valve stem  12  is depressed, as shown in  FIG. 2 , the button  18  moves down within the recess  20 . In that condition, edge recesses or openings  25  in the button  18  permit communication from within the container through these openings  25  to the valve stem openings  22  so that product can be dispensed.  
         [0028]     The upper portion of the grommet  14  is called a boot  26 . A center section  28  of this boot collapses under vertical pressure, as shown in  FIG. 2 , so as to permit the valve stem  12  to move down and place the valve stem openings  22  in communication, through the button edge recesses  25 , with the product to be dispensed.  
         [0029]     This opening and closing of the valve involves an engagement between the upper surface  30  of the boot  26  and a downwardly facing surface  31  of a shoulder  32  in the valve stem  12 . The shoulder  32  engages the boot  26  so that the boot section  28  buckles outwardly when finger pressure is applied to force the stem  12  in a downward direction. But the resilient nature of the boot  26  material pushes the boot  26  up once finger pressure is removed thereby closing the valve. The valve is held tightly closed by pressure underneath the button  18  from the pressurized material in the container. The boot  26  material is selected to have a resilience appropriate to the pressures required in a particular design.  
         [0030]     When the valve is open, as shown in  FIG. 2 , the passage of the Product P is through the edge recesses  25  (see  FIG. 3 ) in the button  18 , then through the openings  22  in the valve stem, then up the center passage  34  in the valve stem  12  and out through the actuator  16 .  
         [0031]     The problem that occurs in connection with these vertically actuated valve stem designs is that in certain circumstances the pressure required to open the valve is sufficiently great so that the upper end of the boot  26  can occasionally snap around the shoulder  32  thereby essentially disabling the valve and holding it open.  
         [0032]     A design which overcomes this problem of loss of proper engagement between boot  26  and shoulder  32  is one that includes an inwardly facing annular flange  36  at the upper edge of the boot  26  and an engagement between this flange  36  and an annular recess  38  in the stem  12 .  
         [0033]     Because of the small sizes of the flange  36  and recess  38 , dictated by the small size of the entire valve structure, it is important that various dimensional relationships be selected to assure that the boot flange  36  is fully inserted into the stem recess  38 . In order to achieve this full insertion result and in view of the inevitable variations due to tolerance and manufacture, the following relationships have been found to be valuable and are preferred.  
         [0034]     It is important that the opening  40  to the annular recess  38  be greater than the thickness of the flange  36  so that the recess opening  40  will not obstruct the full insertion of the flange. It is the engagement between the upper surface  30  of the boot and the lower surface  31  of the shoulder  32  that brings about opening and closing. Thus a tight fit between flange  36  and recess  38  is of little significance and could actually create resistance to the full insertion of the flange  36  into the recess  38 . As shown in  FIG. 5 , this dimensional relationship is arranged by having a sloping surface  42  for the lower surface of the recess  38 .  
         [0035]     A further feature that aids in assuring the full insertion of the flange  36  into the recess  38  is to have an interference fit relationship between the annular surface  44  of the boot immediately below the flange  36  and the corresponding annular surface  46  of the valve stem  12 . This assures that no part of the flange  36  sits outside of the recess  38 .  
         [0036]     It is also useful that the recess  38  extend inwardly nominally more than the length of the flange  36  and that the inner thickness of the recess  38  be at least nominally greater than the thickness of the inner edge of the flange  36 . These two clearance relations work together to assure room for the flange  36  in the recess  38  and thus removes the possibility that the flange will not fully sit within the recess. These two clearances also provide room to accommodate flange distortion under pressure when the valve is opened.  
         [0037]     The stem diameter just below the recess is greater than the corresponding boot diameter. The design value in one embodiment are that the stem diameter is 152 mils and the corresponding boot diameter is 148 mils. This four mil diameter difference serves to compensate sufficiently for manufacturing tolerances and to assure that the entire flange will be inserted into the stem recess.  
         [0038]     In large part for reasons of assembly of grommet and stem, the diameter of the shoulder  32  cannot be as great as might be desired for the purpose of assuring that the boot does not snap over the shoulder. It becomes useful to make sure that the upper surface  30  of the boot extends radially outward to at least the outer end of the downwardly facing surface of the shoulder  32 . This provides as much of an engagement surface as possible thereby minimizing unit pressure area and further helping to assure that the forces between boot  26  and shoulder  32  are resolved to reduce the tendency for the boot to snap over the shoulder.  
         [0039]     A 45 degree fillet  48  at the corner of the flange  36  and boot wall  44  serves to guide and keep the flange  36  in place. The 45 degree surface  42  at the recess opening provides room to accommodate the fillet  48 .  
         [0040]     The valve stem opening  22  shown in  FIG. 3  is deemed optimum for use with a liquid flowable product such as a gel shave. By contrast, when dispensing a product as a spray or mist or aerosol, it has been found preferable to employ a more rectangular valve stem opening such as shown in  FIG. 3A .  
         [0041]     The approximately triangular opening  22  of  FIG. 3  permits the user to meter out the amount of product being dispensed by the extent to which the user depresses the valve stem. By contrast, for spray products, a minimum volume of liquid is required in order to effect an adequate spray from the spray head. If used for spray dispensing, the triangular opening  22  of  FIG. 3  tends to result in a dribbling of product initially and at the end of the closing of the valve. The  FIG. 3A  rectangular opening  22   a  minimizes this problem.  
         [0042]     In one product designed for a gel shave, the inverted triangular opening  22  has the following dimensions: a 50 mil length or height; a 42.5 mil upper edge and a 10 mil tip or lower edge.  
         [0043]     A typical valve stem opening  22   a , such as is shown in  FIG. 3A , for a product providing a spray or mist has a height of 50 mils and a width of 20 mils.  
       An Example of the Embodiment  
       [0044]     The following table presents an example of a single embodiment of this invention in which the dimensional relationship discussed above are represented by a specific set of dimensions. The following provides an indication of the nominal nature of the interference and clearances which assure the full insertion of the flange  36  into the recess  38 .  
                                                             MILS                                        Stem Shoulder 32 Diameter   230           Stem Recess 38 Inner Diameter   122           Stem 46 Diameter below Recess   152           Stem Recess 38 Width at Inner Diameter   24           Stem Recess 38 Width at Recess Opening   32           Stem Recess 38 Depth   15           Boot 26 Upper Edge Diameter   230           Boot Flange 36 Inner Diameter   124           Boot Flange 36 Thickness   20           Boot Inner Diameter 44 below Flange   148           Boot Flange 36 Length   13           Interference between Boot 26 Diameter   4           And Stem 46 Diameter below Recess (152-148)           Clearance between Boot Flange 36   4           Thickness and Stem Recess 38 Width at their           Inner Ends (24 minus 20)           Clearance between Boot Flange 36   2           diameter and Stem Recess 38 diameter           (122 minus 124)                      
 
         [0045]     While the foregoing description and drawings represent the presently preferred embodiments of the invention, it should be understood that those skilled in the art will be able to make changes and modifications to those embodiments without departing from the teachings of the invention and the scope of the claims.