WO1999046183A1

WO1999046183A1 - Gasketed aerosol mounting cup

Info

Publication number: WO1999046183A1
Application number: PCT/US1999/005199
Authority: WO
Inventors: Valve Corporation Precision; Robert H. Abplanalp; Charles S. Radtke
Original assignee: Precision Valve Corp
Priority date: 1998-03-10
Filing date: 1999-03-10
Publication date: 1999-09-16
Also published as: AU2996099A

Abstract

An improved gasketed mounting cup (14) for an aerosol container (12), said mounting cup having a flat bottom channel portion (22), said gasket having inner and outer folded-over segments (36, 38) wherein the outer segment extends beyond the free-end terminus of the inner segment, and further wherein the segment of the body of the mounting cup merging into the channel portion of the mounting cup is displaced laterally toward the skirt portion (24) of the mounting cup, as compared to the segment of the body of the mounting cup distal to the channel portion of the mounting cup.

Description

GASKETED AEROSOL MOUNTING CUP

This application is a continuation-in-part of United

States Patent Application Serial No. 08/512,533, filed on

August 8, 1995, naming Robert H. Abplanalp and Charles S.

Radtke as inventors, which application was abandoned in favor of U.S. Serial No. 08/867,609, filed on June 2, 1997.

This invention generally relates to valve mounting assemblies for aerosol containers, said mounting assemblies being commonly referred to as "gasketed mounting cups." More particularly, this invention relates to an improved gasket for the mounting cup, i.e., the gasket that forms the seal between the perimetal rim of the mounting cup and the bead of the aerosol container, wherein the sleeve gasket is folded over on itself to provide a double thickness of gasket material disposed within the channel portion of the mounting cup. Also, the invention concerns modifying the dimensions of the channel portion of a conventional aerosol mounting cup to better assure the proper position of the folded-over gasket in the channel portion of the mounting cup.

Background Of The Invention;

Aerosol containers are widely used to package a variety of fluid materials, both liquid and powdered particulate products. Typically, the product and a propellant are confined within the container, at above atmospheric pressure, and the product is released from the container by manually opening a dispensing valve to cause the pressure within the container to deliver the product through the valve and connecting conduits to a discharge orifice.

The dispensing valve, crimped to a mounting cup having a sealing gasket, is normally mounted in a top opening of the container, which opening is defined by a component commonly referred to as the "bead" of the container opening. The mounting cup includes a central pedestal portion for holding the dispensing valve, a profile portion extending outward from the pedestal portion, which profile portion merges into an upwardly extending body portion, the body portion emerging into a hemispherically-shaped channel portion terminating in a skirt portion, which channel portion is configured to receive the bead portion of the container opening. The sealing gasket normally is disposed within the channel portion and in many gasket configurations extends downward along a part of the body portion. After the sealing gasket is disposed onto the mounting cup, the cup is positioned onto the container and the cup is clinched to the container. The clinching operation is well-known to those skilled in the aerosol container art.

In an aerosol container, an effective seal between the gasketed mounting cup and the container bead is obviously critical. This seal is accomplished through the sealing gasket, which must prevent the loss of pressure (propellant) through the interface between the container bead and mounting cup.

Various types of sealing gaskets are known in the art. One common type of gasket comprises a conventional flat rubber gasket that is placed inside the channel of the mounting cup. Gaskets of this type are typically manufactured by extruding, molding and vulcanizing the compounded rubber mixture onto rods and then cutting or slicing off thin, annular sections of the extruded and vulcanized product (tube) . These gaskets are often referred to as cut or flat gaskets. Cut gaskets are relatively expensive to manufacture. It is very difficult to control precisely the radial dimensions of the tubes, from which the cut gaskets are made, the tubes having varying dimensions and being out of round. Consequently, the outer cylindrical surfaces of these tubes are usually machined to the desired dimensions, said machining adding considerable cost to the gasket manufacture.

Another type of gasket comprises a relatively thin sleeve of elastomeric material that is mounted on the body portion of the mounting cup and then advanced along said body so that the gasket extends ultimately into a limited portion of the annular channel of the mounting cup as well as downward along the body portion beyond the annular clinch zone. When the mounting cup is mounted and then clinched onto the aerosol container, the sealing gasket is forced into a sealing engagement with both the channel of the mounting cup and the bead of the container. Typically, these gaskets are forced into a sealing engagement with the mounting cup along only a relatively small circumferential portion of the gasket at positions referred to as the 5 o'clock and 11 o'clock positions. Due to their shape, gaskets of this type are often referred to as sleeve gaskets. Sleeve gaskets are manufactured by advancing a tube of gasket material onto the body of the mounting cup and then cutting or slicing off an annular section of the tube. The axial heights of sleeve gaskets, however, are substantially greater than the axial heights of a cut gasket. Sleeve gaskets are much less expensive to make and assemble to the mounting cup than cut gaskets. When making sleeve gaskets, it is not necessary to machine the outside cylindrical surface of the extruded tubes of gasket material. Moreover, a tubular sleeve gasket may be assembled to the mounting cup more easily than assembling a cut gasket to the mounting cup.

The sealing gasket may also be formed by a liquid material containing water or solvent that is deposited on the annular channel and body portion of the mounting cup. The solvent or water evaporates during curing and the remaining material produces a resilient sealing material in the mounting cup channel. Forming the gasket from a liquid material also is a comparatively expensive procedure requiring multiple production steps including the use of curing ovens or other means to dry and cure the gasket material. Moreover, means must be provided for rotating the mounting cup beneath and relative to a metering apparatus that dispenses carefully determined amounts of a gasket forming composition. These gaskets are commonly referred to as "flowed-in" gaskets. The "flowed-in" gasket system has been disfavored recently due to environmental concerns .

Thus, the above described types of gaskets, as well as others that may be used, have both advantages and disadvantages. Both cut and sleeve gaskets generally produce excellent sealing results. Cut gaskets have seen widespread commercial use for a longer period of time than sleeve gaskets. When using sleeve gaskets on filling and clinching equipment previously used with flat or cut gaskets, a time consuming adjustment is necessary to the clinching tool. Often, a clinching line will be required to accommodate both flat and sleeve gaskets, depending on the gasket specifications of the valved container being clinched. To avoid having to make the clinching tool adjustment, and the consequent down- time, there has been a tendency, particularly in Europe, to stay with flat or cut gaskets, even though such gaskets are more costly.

In the past, an attempt has been made to overcome the disadvantages of a cut gasket by converting a specially dimensioned sleeve-type gasket into a cut-type gasket. This attempt is described in U.S. Pat. Application Serial No. 08/384,736, filed on February 3, 1995. A disadvantage of utilizing the aforementioned sleeve to cut-type gasket is that the apparatus used to manufacture the sleeve-type gasket is designed to handle tubing having a thickness on the order of .014". Cut gaskets generally are .040" thick, and to manufacture sleeve-type gasket material for conversion into a cut- type gasket of .040" or more requires a significant retooling.

A further attempt to generate a cut gasket from a sleeve- type gasket is set forth in U.S. Patent Application No. 08/512,533, filed August 8, 1995, naming Robert H. Abplanalp and Charles S. Radtke as the inventors. In the 08/512,533 application, a sleeve gasket is advanced along the body portion of the mounting cup into the channel portion of the cup, whereat a tool advances against the sleeve and causes the sleeve to fold over onto itself. Further advancement of the folded-over gasket to its ultimate position within the channel portion of the cup is then effected.

It has been found that the gasket and gasket system of the 08/512,533 application, especially when utilized with mounting cups having a curvilinear channel portion and in association with aluminum aerosol containers, had a higher leakage percentage than desired. The bead (portion forming the container opening) of aluminum containers are formed by a necking-in process which results in the formation of fissures, commonly referred to as eye-lashing, in the bead of the aluminum container from the top mid-point toward the radially inward arc extending therefrom. In aerosol industry parlance, the mid-point of the bead of the container is referred to as 12 o'clock and the further point radially inward from 12 o'clock is referred to as 3 o'clock. Such fissures may provide leak paths for the propellant to escape from the container. The subject invention overcomes the limited failing of the prior art.

SUMMARY OF THE INVENTION

An object of this invention is to provide an improved gasketed mounting cup for aerosol containers and an improved method for assembling the gasket to the mounting cup. Another object of the present invention is to provide a mounting cup for an aerosol container with a sealing gasket that has the manufacturing cost advantages of a sleeve gasket and the advantages of the thickness of a cut gasket in the clinching operation of the aerosol container.

These and other objectives are attained through use of the gasketed mounting cup of this invention.

In its broadest aspect, the gasketed mounting cup of this invention comprises a flat mounting cup having a flat-bottomed channel portion and having a folded-over gasket formed from a sleeve- type gasket, which folded-over gasket has an inner segment contiguous to the mounting cup and an outer segment folded onto the inner segment, which outer segment has a greater length than the inner segment, in combination with a reduction in the width of the channel portion of the mounting cup as compared to that of a conventionally sized mounting cup to foreclose the lateral or side to side movement of the folded-over gasket, thereby negating any tendency of the folded-over gasket to be disposed in a canted position within the channel portion of the cup when the cup and the bead of the container are clinched together to form a seal between the gasketed mounting cup and the container bead. In a preferred embodiment, the folded-over gasket thickness has been reduced compared to that of a conventional cut gasket. The gasket of this invention is formed by advancing the gasket material in the form of a sleeve along the body portion of the mounting cup and into the channel portion of the mounting cup and thereat advancing a tool that creates an annular line of compressive force against the gasket at a point beyond the mid-point of the width of the sleeve to thereby effect a fold line in the gasket with the result that the segment of the gasket most advanced into the channel portion folds over on the other segment of the gasket material .

After the longer segment of the gasket has been folded onto the other segment, and at the point in the manufacturing process where the gasket is partially in the channel portion, the gasket is then urged further into the channel portion of the mounting cup. In the instance where the channel portion of the mounting cup is flat, the gasket will be ultimately disposed against the flat surface of the bottom of the channel portion. Advancement of the gasket to its ultimate position in the channel portion of the mounting cup may be accomplished through the use of a tool or through advancement by placing the gasketed mounting cup on the bead of the container.

In sum, in the process of this invention, a continuous tubular member is initially positioned onto the body portion of the mounting cup. The tubular member is then cut to dispose a sleeve of gasket material on the body portion of the cup. After cutting, the sleeve gasket is then partially advanced along the body portion of the mounting cup and then further advanced into the annular channel thereof in two separate steps. The clinching of the mounting cup and container then occurs . Further benefits and advantages of the invention will become apparent from a consideration of the following detailed description given with reference to the accompanying drawings which specify and show preferred embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a partial cross-sectional view of the gasketed mounting cup of this invention disposed in unclinched position on the bead of an aerosol container. Figures 2A-2F are views in cross -section of the gasketed mounting cup of this invention showing the sequential steps for forming the gasketed mounting cup; the apparatus for advancing and folding over the sleeve gasket being shown in schematic. Figure 2A shows the mounting cup of this invention with a tubular sleeve gasket in its initial position of disposition on the body portion of the mounting cup.

Figure 2B shows the tubular sleeve gasket being advanced onto the body portion of the mounting cup. Figure 2C shows the tubular sleeve gasket positioned to be advanced by a tool having a sharp leading edge.

Figure 2D shows the tubular sleeve gasket on the mounting cup being advanced into the channel portion of the mounting cup and the tool bottoming against the channel portion of the mounting cup to form plural segments of the gasket.

Figure 2E shows the tubular sleeve gasket segment most advanced onto the mounting cup folded over onto the other segment of the gasket. Figure 2F shows the folded-ever sleeve gasket being disposed in the bottom of the channel portion of the mounting cup.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Figure 1 illustrates a valve mounting assembly, generally shown at 10, positioned within the open end 32 of a container 12, shown in partial section. More specifically, valve assembly 10 (valve unit not shown) includes a mounting cup, generally designated as 14, and gasket 16. The mounting cup, in turn, includes a pedestal portion 18, a profile portion 19, and a body portion 20 terminating in a radially outwardly flat channel portion 22 that receives the gasket 16, the channel portion 22 terminating in the skirt 24. Container 12 includes upper portion 30 that forms central container opening 32 and an upper rolled rim or bead 34 that extends around opening 32. As shown in Figure 1, channel portion 22 of cup 14 is mounted on and receives bead 34. Gasket 16 is disposed between bead 34 and the under surface of channel 22. The bead 34 directly supports the valve mounting assembly 10.

Again, with reference to Figure 1, in order to connect assembly 10 permanently to container 12, a portion of the body 20 is forced radially outward, underneath bead 34, around the circumference of body 20 thereby clinching the mounting assembly 10 to container 12. This clinching operation also forces gasket 16 into a tight pressure fit against both bead 34 and the under-surface of channel 22, thereby forming an effective seal therebetween. The clinching operation is well known to those skilled in the art.

Note that the folded-over gasket of this invention has a segment 36 of the gasket contiguous to the channel portion 22 that is shorter than the segment 38 folded onto the segment

36.

It should be further noted that the channel portion 22 is substantially flat in its traverse from the body portion 20 to the skirt portion 24 of the mounting cup 10 except at the termini where the channel merges into the body portion and the skirt portion, respectively.

Further, the body portion 20 of the mounting cup 10 has an upper segment 40 and a lower segment 42, the upper segment 40 merging with the channel portion 22 and the lower segment

42 merging with the profile portion 19 of the mounting cup 10.

At the joinder of the upper 40 and the lower 42 segments of the body portion 20, there is radially outward step 44, which reduces the distance "D" between the inner wall of the skirt portion 24 and the outer wall of the upper segment 40 of the valve body 20.

As shown in Figures 2A-2F, the gasket configuration and positioning of the gasket of this invention onto the mounting cup is formed in a series of steps commencing with the positioning of a portion 72 of a tubular gasket material onto the body portion 20 of a mounting cup 14. Subsequently, the tubular portion 72 of gasket material is cut by cutter 70 (see

Figure 2A) to provide a mounting cup 14 having a sleeve of tubular gasket material extending slightly above the profile portion 19 of the mounting cup. See Figure 2A.

After cutting the tubular gasket 72, the gasket 72 is partially advanced onto the body portion 20 of the mounting cup 14 by a suitable punch 74 to the position shown in Figure 2B to form a sleeve gasket. Then, the sleeve gasket 72 is advanced further onto the body portion 20 and into the channel portion 22 by a punch 76 (see Figure 2C) having a relatively sharp nose portion 78. Details of the punch construction for ultimately positioning the sleeve gasket are described hereafter. By bottoming the relatively sharp nose portion of the punch against the sleeve gasket positioned in the channel portion of the mounting cup, and with the mounting cup and its supporting member offering an opposing resistance to the force of the punch, a fold line 80 is created in the sleeve gasket at a point beyond the mid-point of the width "W" of the sleeve gasket, with the consequence that the segment of the sleeve gasket most advanced into the channel portion of the mounting cup folds onto the segment of the sleeve gasket which is contiguous to the body portion of the mounting cup. The steps of advancing the sleeve gasket within the channel portion of the mounting cup and bottoming the sharp-nosed punch against the gasket within the channel portion of the mounting cup are shown in Figures 2C and 2D. With the flat channel, the punch 50 shown in Figure 2D is retracted and the mounting cup moved to a station whereat the flat bottom punch 60 shown in Figure 2F advances to flatten the folded-over gasket against the bottom of the channel portion. As shown in Figure 2F, the ultimate positioning punch 60 advances the gasket against the flat surface of the channel .

As noted earlier, advancement of the folded-over gasket against the bottom of the channel portion of the mounting cup may be accomplished during the clinching of the mounting cup to the bead of the container, that is, when the mounting cup is placed on the bead for clinching, the bead will advance the gasket to the ultimate desired position against the bottom of the channel portion.

Also note that it is important, particularly where the mounting cup/aerosol container is to be under- the-cup filled, i.e., where the propellant is introduced to the container by introducing the propellent by vacuum evacuation of the air in the container through a space between the mounting cup and the bead of the container, that the folded-over gasket not extend beyond the terminal edge of the skirt portion of the mounting cup.

The apparatus for conducting the Steps 2A - 2B is described in United States Patent No. 4,546.525, issued October 15, 1985; the disclosure of said U.S. patent being incorporated by reference herein.

The apparatus and process for carrying out the steps shown in Figures 2A - 2F are also described in United States Patent Application No. 08/512,533 filed on August 8, 1995, the disclosure of which application is hereby incorporated by reference. The steps of Figures 2C - 2D are carried out by mounting a punch 76 (see Fig. 2C) having a serrated nose 78. It has been found satisfactory in carrying out the Steps of 2C - 2D to place the inverted mounting cup of Figures 2B atop a piston surface (not shown) that moves within a four inch (4") cylinder. The cylinder is charged to 20 psi to create a resistive force of 250-plus lbs. against the advancing serrated punch. The punch used to form the junction or fold- over line is fully described in U.S. Patent Application Serial No. 08/512,533, filed on August 8, 1995.

In the most preferred form, the radial thickness of the sleeve gasket material is sixteen and one-half thousands of an inch (.0165"), however, it is believed that said preferred thickness may vary between .0155" -.0175" . When the segments of the gasket are folded onto each other, the composite thickness of the gasket where there is overlap is thirty-three thousands of an inch (.033") in the instance where the thickness of the sleeve is .0165". A sleeve gasket width "W" of two hundred thousands of an inch (.200") has been found satisfactory. Firming the fold-over junction at a point on the sleeve gasket that yields gasket segments of .090" and .110" has been found to yield a satisfactory seal. However, variations in the length of these segments will expectedly produce a satisfactory seal. Critical is that the segment distal to the bottom of the channel portion have a greater length than the other segment. So arranging the lengths of the gasket segments avoids the possibility of the sleeve unfolding during positioning in the channel portion of the mounting cup .

Mounting cups of the type described above are well known in the art, and cups may be made by any appropriate procedure and from any suitable material. For instance, cups may be made of metal such as steel, aluminum, and the like and formed into the desired shape through a stamping process. In the preferred embodiment of this invention, the upper segment of the body portion of the mounting cup has a diameter of .996" and the lower segment of the body portion has a diameter of

.989".

Gasket material useful in this invention may be a polyolefin such as, for example, polyethylene (PE) and polypropylene (PP) . Rubber modifiers such as, for example, polyisobutylene may be added to the PE and PP. A preferred gasket material is 80% linear low density polyethylene and 20% polyisobutylene (80% LLDPE/20% PIB) .

If desired, the tubular gasket material may have coated on one or both surfaces an adhesive compound that is activatable after the gasket material has been disposed in its alternately desired position. Adhesive materials that have a delayed activation are well known to those skilled in the art.

There are many advantages to forming the gasket of this invention from sleeve- type gaskets. Among the advantages are: a) Cost Reduction:

1) eliminates machine cutting of gaskets;

2) assembly at higher speeds using sleeve gasket assembly technology; 3) tubing is extruded without required O.D. machining . b) Superior Gasket Retention:

Cut gaskets of the prior art have a tendency to become dislodged from the mounting cup during the handling operations prior to clinching of the gasketed mounting cup. The gaskets of this invention show a marked improvement in stability on the mounting cup. The folding of the gasket at the hinge results in the top segment (e.g. as shown in

Figures 4E and 4F) being highly stretched and thereby acting to maintain the gasket on the mounting cup . c) Sleeve gaskets provide a much broader selection in materials of construction, including blends of materials, than do the cut gaskets of the prior art. d) Eliminates dust common to machine cutting gaskets. e) Eliminates problems due to warpage in the cut gaskets of the prior art. f) With rubber cut gaskets, the industry experiences a so-called "squeeze out" problem familiar to those skilled in the art.

While it is apparent that the invention herein disclosed is well calculated to fulfill the objects previously stated, it will be appreciated that numerous modifications and embodiments may be devised by those skilled in the art, and it is intended that the appended claims cover all such modifications and embodiments as fall within the true spirit and scope of the present invention.

Claims

We claim :

1. In a gasketed valve mounting cup assembly for an aerosol container comprising a mounting cup having a central pedestal portion for affixing an aerosol valve, a profile portion emerging outward from the pedestal, a body portion extending upwardly from the outward terminus of the profile portion and terminating in a channel portion for receiving the bead of a container, said channel portion having an under surface, and terminating in a skirt portion, the improvement comprising, in combination, the channel portion of the mounting cup being substantially flat except in the areas where the channel portion merges into the skirt portion of the mounting cup, a gasket having inner and outer gasket segments folded onto each other along a fold line or hinge disposed within the channel portion of the mounting cup, said inner segment being nearest the mounting cup and the outer segment of the gasket extending beyond the free end of the inner segment and the body portion of the mounting cup having upper and lower segments, the upper segment merging into the channel portion and being displaced laterally toward the skirt portion of the mounting cup relative to the lower segment .

2. The improvement of claim 1 and further wherein the fold line or hinge of the gasket is distal to the body portion of the mounting cup.

3. The improvement of claim 1 and further wherein the gasket is disposed against the flat bottom of the channel portion of the mounting cup prior to the clinching of the mounting cup to an aerosol container.

4. The improvement of claim 2 and further wherein the gasket is disposed against the flat bottom of the channel portion of the mounting cup prior to the clinching of the mounting cup to an aerosol container.

5. The improvement of claim 1 and further wherein the gasket is disposed beneath the terminal edge of the skirt portion and diagonally within the channel portion of the mounting cup with the free edge of the segmented gasket contiguous to the body portion of the mounting cup prior to the clinching of the mounting cup to an aerosol container.

6. The improvement of claim 2 and further wherein the gasket is disposed beneath the terminal edge of the skirt portion and diagonally within the channel portion of the mounting cup with the free edge of the segmented gasket contiguous to the body portion of the mounting cup prior to the clinching of the mounting cup to an aerosol container.

7. The improvement of claim 1 and further wherein the combined thickness of the gasket segments ranges from 0.031 inches to 0.035 inches.