US 2880900 A
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April 7, 1959 B. FoYE 2,880,900
` EXPANDABLE DAPPIIRAGIVIv AS A CUSHION IN LOOSE PACKED BOTTLES Filed 0G12. 3, 1955 United States Patent EXPANDABLE DIAPHRAGM AS A CUSHION LOOSE PACKED BOTTLES Allen Bradford Foye, West Bridgewater, Mass., assigner to W. R. Grace & Co., Cambridge, Mass., a corporation of Connecticut Application October 3, 1955, Serial No. 538,083
1 Claim. (Cl. 215-40) This invention relates to container closures and particularly to a closure designed to be used on jars or cans in which solids are packed. Presently, hard candies are packed in jars and, when a weighed amount of the candy is inserted in the jar, a crumpled piece of waxed paper is inserted through the mouth of the jar to hold the candies and prevent them from abrading during shipment.
Pharmaceutical products, particularly tablets, are also packed in this manner, but usually a wad of sterile cotton instead of paper is pushed through the neck of the bottle just prior to the capping operation. Small mechanical parts such as watch and small radio components are also packed in the same manner.
The closure which I have developed eliminates the need of paper or cotton stuffing and, in addition, gives the advantage of vacuum packing to the contents. Vacuum packing prevents the absorption of moisture. In the case of hard candies, this is a particular advantage because the hygroscopic nature of candies causes them to stick together during transit. In the case of mechanical parts, it prevents the rusting of steel or the oxidation of other metals.
If a container is sealed under vacuum (for example in a mechanical vacuum closing machine) and if the entire interior surface of the closure is made of an extensible, air impervious diaphragm, the diaphragm will form the normal sealing gasket and maintain the internal vacuum; then, additionally, if a minute puncture is made through the metal only of the top panel, air pressure above the diaphragm will cause it to balloon from its restrained margins, and expand to ll the unoccupied vacuum space. It comes to rest against the irregular packing pattern of the contents. The package may be bumped and jolted, but wedged down by the balloon, the separate parts cannot move.
Should one so choose, although the cost of the pulp V` liner must be considered, the diaphragm may be applied over the conventional pulp liner used in many jar and cap closures. Such liners are not impervious to air and, after the jar or the can has been closed as described, it will be found that in a few minutes suicient aii has leaked between the threads and through the pulp to expand the diaphragm in the same manner as when a minute hole is made through the metal.
The invention will be clear from the accompanying drawings, in which- Figure l is a vertical section through a common screw or CT jar cap,
Figure 2 is a vertical section through CT cap provided with a pulp liner,
Figure 3 is an elevation showing the improved closure applied to a jar of hard candies, and
Figure 4 is an elevation showing the invention applied to a broken thread screw top can.
In Figure 1 the CT screw cap 10, is provided with a diaphragm 11 of rubber or rubbery material which covers the entire inner surface of the cap. The diaphragm 11 can be made slightly thicker around the channe or norrice mal sealing area 13, but it must extend entirely across the panel 14.
Referring to Figure 3, the cap of Figure 1 is shown applied to a jar 15 of hard candies. After the cap 10 has been applied in a vacuum closing machine, the minute hole 16 is pierced through the panel 14, diaphragm 11 expands as is shown, pressing down on the top layer of sour balls, which are now cushioned against movement.
In Figure 2 a CT cap 10a is shown provided with a pulp liner 17 over which the diaphragm 11a is placed. As was explained, it is not necessary to pierce the top panel when such a closure is vacuum sealed on a jar. In a short time after sealing, enough air will have leaked through the pulp liner 17 to cause the diaphragm 11a to assume the position of diaphragm 11 in Figure 3.
In Figure 4, the diaphragmllb has been applied across the inner surface of the closure 18 of a broken-thread, removable top can 19. The minute hole 21 has allowed the diaphragm 11b to expand into and till the normal head space in can 19.
Any material which is essentially air-impervious, extensible and somewhat resilient so that a proper seal is formed around the mouth of the container is suitable as a diaphragm. There are many elastomeric substances besides natural rubber and several plasticized resins which meet these requirements among which may be mentioned natural rubber, butadiene-styrene copolymers, butadiene acrylonitrile, copolymers, vinyl polymers, polyvinyl butyrals, and super polyesters of the nylon type. These may be formed or molded and inserted in the closure or they may be poured in in liquid form and converted to a solid diaphragm by drying.
I prefer, however, to make the diaphragm from a vinyl plastisol because the manufacture of diaphragm lined caps can then become both rapid and simple. The plastisol is owed into the cap by any of the conventional lining machines now used in the container closure industry, and the liquid plastisol can be liuxed" or converted to a solid diaphragm in but a few seconds by heating the closure in a properly designed oven.
Any closure which loses its liner in handling prior to capping is an industrial nuisance. The diaphragm must be adhered to the cap suiciently to prevent its falling out in handling prior to closing the jar. If the diaphragm is molded or cut from a sheet, it is cemented to the closure by a layer of cement applied to the channel 13 only. No cement is necessary when latex or plastisols are used, but the degree of adhesion to the panel must be kept low. This can be achieved by various means. For example, vinyl plastisols will stick tenaciously to a vinyl base tin plate enamel, but if the enamel be oleoresinous, the mild adhesion is suicient to prevent the diaphragm from falling out during handling, but is insuficient to prevent the diaphragm from being blown away from the panel after the panel is punctured.
Because air is admitted over the diaphragm, my closure is not operative with top seal and other types of closures which depend upon the continuance of vacuum beneath the cap to hold the closure in place, but it is suitable for any closure which is provided with threads or lugs or any holding device which mechanically secures the closure to the container.
Iclaim: In a sealed container including a container element and a rigid closure element said closure element including a top closure panel and a closure retaining skirt, means to prevent the movement of solid contents, comprising van essentially air-impervious, extensible elastomeric diaof said elements thereby forming a sealinggasket for said container, the rem'ai'ndelof said diaphragm being exposed to atmospheric pressure on its closureside and to subatmospheric pressure on itsv container side, the said difference in pressure causing s aid remaining portion of the -diaphragm to balloon into the free space within the container thereby forming a cushion packing for its contents.
References Cited in the le of this patent UNITED STATES PATENTS Griswold etal Mar. 23, 1880 Eisen Feb. 25, 1941 Wright Apr. 7, 1942 FOREIGN PATENTS France Mar. 15,. 1950