US20080116231A1

US20080116231A1 - Valve for use in a container which employs pressure to dispense product

Info

Publication number: US20080116231A1
Application number: US12/009,518
Authority: US
Inventors: Christian Scheindel
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-10-31
Filing date: 2008-01-18
Publication date: 2008-05-22

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

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

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.
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.
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.
Applicant'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.
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.
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.
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.
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.
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

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.
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.
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.
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

Nominal Clearance
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.
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.
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.
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.
Up and Down; Lower and Upper
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

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.
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.
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.
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.
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

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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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

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)

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.

Claims

1. In a vertically movable valve for use in a pressurized dispensing container, the valve movable between an upper closed state and a depressed dispensing state, the valve including a valve stem with an axis, at least one dispensing opening at a lower zone of the stem, the improvement in a resilient annular sealing grommet around the stem, comprising:

an upper boot portion of said grommet having an upper edge,

a shoulder on said valve stem,

said shoulder and said upper edge of said grommet engaging to provide a restoring force when said valve is depressed,

an inwardly extending annular flange at said upper edge of said boot,

an annular recess on said stem, said recess being adjacent to and below said shoulder,

said boot flange and said stem recess engaging to provide full insertion of said flange into said recess.

2. The improvement of claim 1 wherein: said stem recess has an opening whose width is greater than the thickness of said boot flange.

3. The improvement of claim 1 wherein: the inner diameter of said boot below said flange has an interference fit relation to the outer diameter of said stem below said recess.

4. The improvement of claim 2 wherein: the inner diameter of said boot below said flange has an interference fit relation to the outer diameter of said stem below said recess.

5. The improvement of claim 1 wherein said flange has a lower surface and said boot has an inner wall further comprising: a fillet at the juncture between said flange lower surface and said boot inner wall.

6. The improvement of claim 2 wherein said flange has a lower surface and said boot has an inner wall further comprising: a fillet at the juncture between said flange lower surface and said boot inner wall.

7. The improvement of claim 3 wherein said flange has a lower surface and said boot has an inner wall further comprising: a fillet at the juncture between said flange lower surface and said boot inner wall.

8. The improvement of claim 4 wherein said flange has a lower surface and said boot has an inner wall further comprising: a fillet at the juncture between said flange lower surface and said boot inner wall.

9. The improvement of claim 1 wherein: there is nominal clearance between the inner end of the boot flange of the inner end of the stem recess, said nominal clearance comprising at least one of a diameter clearance and a thickness clearance.

10. The improvement of claim 2 wherein: there is nominal clearance between the inner end of the boot flange of the inner end of the stem recess, said nominal clearance comprising at least one of a diameter clearance and a thickness clearance.

11. The improvement of claim 3 wherein: there is nominal clearance between the inner end of the boot flange of the inner end of the stem recess, said nominal clearance comprising at least one of a diameter clearance and a thickness clearance.

12. The improvement of claim 5 wherein: there is nominal clearance between the inner end of the boot flange of the inner end of the stem recess, said nominal clearance comprising at least one of a diameter clearance and a thickness clearance.

13. The improvement of claim 8 wherein: there is nominal clearance between the inner end of the boot flange of the inner end of the stem recess, said nominal clearance comprising at least one of a diameter clearance and a thickness clearance.

14. The improvement of claim 1 wherein: the outer diameter of the upper edge of said boot is at least equal to the outer diameter of said shoulder.

15. The improvement of claim 2 wherein: the outer diameter of the upper edge of said boot is at least equal to the outer diameter of said shoulder.

16. The improvement of claim 4 wherein: the outer diameter of the upper edge of said boot is at least equal to the outer diameter of said shoulder.

17. The improvement of claim 13 wherein: the outer diameter of the upper edge of said boot is at least equal to the outer diameter of said shoulder.

18. The improvement of claim 3 wherein: said stem to boot interference is approximately 11 mils on a diameter.

19. The improvement of claim 4 wherein: said stem to boot interference is approximately 11 mils on a diameter.

20. The improvement of claim 17 wherein: said stem to boot interference is approximately 11 mils on a diameter.