US3152711A

US3152711A - Closure cap

Info

Publication number: US3152711A
Application number: US68859A
Authority: US
Inventors: George V Mumford; Norman C Geithman
Original assignee: Owens Illinois Glass Co
Current assignee: OI Glass Inc
Priority date: 1960-11-14
Filing date: 1960-11-14
Publication date: 1964-10-13
Anticipated expiration: 1981-10-13

Description

United States Patent 3,152,711 CLGSURE CAP George V. Mumford and Norman C. 'Geithman, Toledo, Ohio, assignors to GWens-llllinois Glass Company, a corporation of Ghio Filed Nov. 14, 1960, Ser. No. 68,859 Claims. (Cl. 2l5--38) This invention relates to closure caps, and more particularly to sheet metal closure caps for hermetically sealing containers such as jars and bottles which are adapted for the preservation of comestibles.

In the preserving of comestibles it is common practice to place them While in a heated condition in a glass container and to provide a head-space into which steam or an inert gas is introduced. This steam or gas replaces any air that may be present in the head-space of the container. Immediately thereafter the container is closed with a gasket-containing cap. If a tight seal is initially obtained between the cap and container it is known that as the hot food and the receptacle are cooled the entrapped steam condenses and an etlective vacuum is created in the container. The purpose of the gasket is to provide and maintain a hermetic seal in order that the food is preserved during storage.

Due to various uncontrollable factors, it is not always possible to maintain an air-tight seal with the result that over a period of time air which contains various bacteria, molds, etc. may seep into the container and contaminate the food with the result that the consumer may sufier ill effects from consuming such food. The problem then arises as to how this failure of the closure cap to provide an air-tight seal may readily be determined prior to the time at which the container is opened. It often is not possible for a consumer to determine merely by looking at the container or the food therein that the same has or has not been contaminated unless the contamination has progressed to such an extent that it is clearly visible on the food. In the prior art, various closure caps have been proposed for sealing containers. For instance, in U.S. Patent No. 2,458,360 to Pay et al., they propose the provision of a closure device having a curvilinear top portion which allegedly assumes a concave position if sufiicient vacuum is present in the container and a convex position when insufficient vacuum is present. This change in position is also allegedly accompanied by an audible click.

This method has not proved satisfactory because the change from the concave to the convex configuration will take place slowly upon the gradual reduction of the vacuum thereby making it very diflicult, if not impossible, to determine by visual means the absence or presence of the desired vacuum in the container. In addition, the curvilinear top portion renders it almost impossible to stack a container having such a closure cap on top of another container containing a like cap. Also, when the cap is removed the audible click, if present at all, is very faint so that if the consumer has been educated to expect a loud click upon the opening of the container, then upon hearing such a barely audible click, he will naturally assume that the vacuum was not present in the container and that the food may be spoiled. If such occurs, the consumer will be reluctant to use thecontents of the container and may be led to doubt the skill of the manufacturer of the foods, thereby damaging its sales.

It is, therefore, an important object of the present invention to overcome the above described difficulties of the prior art. i

It is a further object of the present invention to provide a sheet metal closure cap which has a panel configuration that assumes a concave position in the presence of a vacuum in the container and rapidly assumes. aconvex 3,152,7ll Patented Get. 13, 1964 position when the desired vacuum is released and is accompanied by a loud click.

It is a further object of the present invention to provide a sheet metal closure cap whose panel configuration is such that the presence or absence of the desired vacuum in the container may be readily determined by touch or sight.

Another object of the present invention is to provide a sheet metal closure cap for hermetically vacuum sealing a container in which the presence or absence of vacuum in the container may readily be determined by mechanical or photo-electrical devices which react to changes in the panel contour of the caps in response to conditions internally of the sealed container.

A further object of the present invention is to provide a sheet metal closure cap of simple construction, which, when used to hermetically vacuum seal a container, will provide a loud audible click when the seal is broken.

The present invention contemplates a closure cap formed from sheet metal having certain specific characteristics, for hermetically vacuum sealing a glass container. This cap comprises a disc-like panel portion, a depending attaching skirt at the periphery of the panel portion and a sealing gasket carried by the cap. The panel portion has an annular substantially flat area in proximity to its periphery and a normally upwardly domed central part peripherally defined by the substantially flat area. When this cap is placed on the glass container and the latter vacuumized, the major portion of the upwardly domed central part assumes a concave configuration. This being in the center of the panel portion makes its presence readily determinable by either sight, touch, or by mechanical devices, which is contrary to the prior art devices whose domed portion consisted of the entire top panel.

If, for some reason, there is seepage of air into the container over a period of time, the vacuum therein will gradually be destroyed and when the vacuum reaches a certain point the cap panel will suddenly move from its concave to its convex position. This movement is accompanied by a very sharp click, thereby audibly indicating the loss of vacuum. More importantly, when the consumer breaks the vacuum seal by removing the cap, such will be accompanied by the same sharp and audible click, thereby indicating that the desired vacuum was present in the container up to the point of its opening. It can readily be seen that such a cap which permits very quick and easy determination of the presence or absence of vacuum in the container will be very useful in the food processing industry, particularly the baby food industry wherein the quick detection of probably spoiled food is most desirable.

The accomplishment of this invention and the foregoing objects will be readily understood by reference to the following detailed description taken in conjunction with the accompanying drawing in which:

FIGURE 1 is a plan View showing the closure device embodying the present invention;

FTGURE 2 is a view partly in elevation and partly in section of the closure cap taken along lines 2-2 of FIGURE 1, such cap being afiixed to a glass container; and

FIGURE 3 is an enlarged sectional view of the closure cap of FIGURE 2.

Referring now to the drawing which illustrates a preferred form of this invention, reference numeral 19 denotes a mouth-defining neck portion of a glass jar 11 which is hermetically sealed by a sheet metal closure cap C. The critical characteristics of this sheet metal will be explained hereinafter. The closure cap C is provided with a conventional or any preferred form of sealing ring or gasket 13 composed of an elastomeric material such I as arubber composition, plastisol or the like. The circular neck 10 of the jar 11 is formed with a relatively flat top sealing surface, or rim 14 and may also be provided with conventional corner and side sealing surfaces. Below the rim 14 and externally of the neck is a closure cap retaining projection 15, such being a continuous screwthread or one of a series of lugs. It may also be formed as a conventional single annular rib over which the cap skirt is forced. The finish of the glass jar 11 is or may well be conventional and requires no further discussion or illustration.

The sheet metal cap C comprises a flat circular top portion, or panel 16, having an annular depending attaching skirt 17 at its periphery which when the cap is affixed to a container surrounds the neck 10 and is radially spaced therefrom. The panel portion 16 is provided with an annular substantially flat area 12 in proximity to its periphery being in a plane normal to the cap axis and a normally upwardly domed central part 18 peripherally defined by the flat area 12.

The normally upwardly domed or convex central part 18 is axially deformable to a concave position as shown by the dotted lines in FIGURE 3. The domed central part 18 is substantially parabolic in shape and thus does not exhibit in cross-section any straight or fiat portions. Preferably the domed central part 13 at its highest point has a radius of about tolO inches and a radius at its periphery of about /2 to 1 inch.

The periphery of the cap panel 16 may assume any desired configuration, such as the illustrated upwardly formed hollow rib 21 which provides an internal gasket accommodating channel 22. This illustrated peripheral configuration is more fully explained in application Serial No. 62,950, filed Oct. 17, 1960, and now Patent Number 3,096,898, in the names of John Hohl and Jack M. Wheaten, entitled Container and Closure Cap Therefor, and owned by the common assignee.

The cap C may be secured to the glass container by any conventional means, such as an internal bead, a screw thread, or as illustrated, peripherally spaced internal lugs 20 which are integrally formed on the lower portions of the attaching skirt 17 and lock with the afore mentioned projections 15 on the container neck.

The upwardly domed central part 18 in the absence of a vacuum normaly assumes the convex configuration shown in full lines in FIGURE 3. When the cap C is placed on a jar 11 and a suitable vacuum is provided in the head-space between the product and the cap, the central part will assume the concave configuration shown in dotted lines in FIGURE 3. The flat area 12 also moves downwardly with the central part. However, such is so slight that it cannot be detected by the naked eye and it has not been illustrated for purposes of clarity. The concave configuration is readily detected by sight or feel and thus it is simple for one to determine that a vacuum is present in the jar 11. This configuration also makes it possible to electronically inspect the filled containers to determine the presence or 'absence of the required vacuum. In the prior art, the caps would scatter the light rays making it very difiicult if not impossible to position the device so as to only reject the containers possessing less than the desired vacuum. The concave configuration of the caps of this invention gathers the light rays into a narrow bandthereby permitting accurate positioning of the device to insure rejection of only the bad containers.

Upon release of the vacuum the domed concave central part 18 snaps to its convex or normal position and this is accompanied by a very loud and audible click. Such a click will assure the consumer that a vacuum was present in the container thereby reassuring him that no contamination is present in the product.

It has been found that the above described results can be obtained only by the use of the aforementioned configuration and the use of sheet metal which has certain critical characteristics. The sheet metal must be that which has a Rockwell hardness (scale T-30) of about 54 to 72. Such sheet metal is commonly referred to as temper three, 54 to 62, temper four, 60 to 64, or Universal temper metal, 64 to 68. If the sheet metal used does not meet this limitation such as with a softer metal, for example, temper one or temper two sheet metal, the sound which may result will be barely audible which is, of course, undesirable. In addition if the central domed part does not exhibit a curved surface in cross-section but instead at least in part is a flat surface, the light directing properties aforementioned will not be obtained. Also, the same will have an adverse effect on the sound producing properties of the cap. For instance a cap produced according to this invention produces twice as much sound as caps which do not have the required upwardly domed central part or are formed from less hard metal such as temper one sheet metal. In addition the frequency of the sound produced by this cap is in the range of 400 to 4000 cycles which is the range where the ear is most sensitive.

It should be apparent from the foregoing that we have discovered that by forming a closure cap of certain specified configuration from sheet metal of certain properties, we are able to obtain a closure cap having important characteristics not heretofore attainable. This closure cap not only provides an effective seal but more importantly provides one by which the presence or absence of the desired vacuum is easily determined. It also provides a very loud click upon the release of the vacuum.

The sheet metal commonly used for these caps is 75, and pound tinplate. However other sheet metals, such as steel that has not been tinplated, may be used equally as well.

Various modifications will be apparent from a reading of the foregoing description and as such are intended to be within the spirit and scope of this invention.

We claim:

1. A sheet metal closure cap for hermetically vacuum sealing a glass container comprising a disc-like panel portion, a depending attaching skirt at the periphery of the panel portion, said panel portion having an annular substantially fiat area in proximity to its periphery, and a substantially parabolic shaped and normally upwardly domed axially resilient central part peripherally defined by the substantially flat area, and a sealing gasket carried by the closure cap, said sheet metal having a Rockwell hardness of about 54 to 72.

2. A sheet metal closure cap for hermetically vacuum sealing a glass container comprising a disc-like panel portion, a depending attaching skirt at the periphery of the panel portion, said panel portion having an annular substantially fiat area in proximity to its periphery and a substantially parabolic shaped and normally upwardly domed axially resilient central part peripherally defined by the substantially fiat area, said parabolic shaped domed part having a radius at its highest point of about 5 to 10 inches, and a sealing gasket carried by the closure cap, said sheet metal having a Rockwell hardness of about 64 to 68.

3. A sheet metal closure cap according to claim 2 wherein said radius is about 7.0 inches.

4. A sheet. metal closure cap according to claim 2 wherein said parabolic shaped domed part has a radius at its periphery of about /2 to 1.0 inch.

5. A sheet metal closure cap according to claim 4 wherein said radius at the periphery of said domed part is about .7 of an inch.

References Cited in the file of this patent UNITED STATES PATENTS 1,805,623 Hammer May 19, 1931 2,027,430 Hansen Jan. 14, 1936 2,423,295 Crabbe et al. July 1, 1947 2,449,014 Shatter Sept. 7, 1948 2,458,360 Fay et al. Jan. 4, 1949 2,953,272 Mumford et al Sept. 20, 1960

Claims

1. A SHEET METAL CLOSURE CAP FOR HERMETICALLY VACUUM SEALING A GLASS CONTAINER COMPRISING A DISC-LIKE PANEL PORTION, A DEPENDING ATTACHING SKIRT AT THE PERIPHERY OF THE PANEL PORTION, SAID PANEL PORTION HAVING AN ANNULAR SUBSTANTIALLY FLAT AREA IN PROXIMITY TO ITS PERIPHERY, AND A SUBSTANTIALLY PARABOLIC SHAPED AND NORMALLY UPWARDLY DOMED AXIALLY RESILIENT CENTRAL PART PERIPHERALLY DEFINED BY THE SUBSTANTIALLY FLAT AREA, AND A SEALING GASKET CARRIED BY THE CLOSURE CAP, SAID SHEET METAL HAVING A ROCKWELL HARDNESS OF ABOUT 54 TO 72.