US2916175A - Screw cap and sealed package - Google Patents

Description

Dec. 8, 1959 D. n. ACTON 2,916,175

scREw CAP AND SEALED PACKAGE Filed May 3, 1957 r 2 Sheets-Sheet 1 IN V EN TOR. Dav /e4 l2 Acre/v v iwm z AIM/vars Dec. 8, 1959 D. D. ACTON SCREW CAP AND SEALED PACKAGE Filed May 3, 1957 2 Sheets-Sheet 2 l l v l INVENTOR. 040/54 Q He Anngyrs 'tinuous thread caps.

United States Patent SCREW CAP AND SEALED PACKAGE Daniel D. Acton, Lancaster, Ohio, assignor to Anchor Hocking Glass Corporation, Lancaster, Ohio, a corpo- The present invention relates to the sealing art and more particularly to a lug type screw cap, the method of making the cap, and to a sealed package.

Screw caps fall into two general classes. First, caps which have a continuous thread to cooperate with a corresponding thread on the container; and second, lug caps which have a plurality of spaced lugs which cooperate with corresponding cams or interrupted threads on the container.

Lug caps are easier to apply and remove than con- One full turn or more may be required to apply or remove a continuous thread cap while a fraction of a turn will apply or remove lug caps. In addition, continuous thread caps tend to grip both the upper and lower part of the container thread and sometimes freeze, whereas this does not occur with a lug cap.

Furthermore, lug caps form more secure seals because the uniform pressure applied at a plurality of points will permit the cap to grip the rim of the container throughout its circumference whereas with continuous thread caps irregularities in the closure and glass finish prevent uniform pressure on the rim of the container throughout its circumference. Lug caps are easy to remove and to reseal and are preferred by housewives. A lug cap can be easilyremoved as compared to the difficult prying-up operation which must be performed on other types of vacuum caps. One difficulty with lug caps is the accuracy required in the manufacture thereof, and the corresponding accuracy required in the manufacture of the glass containers to which they are applied. Because of the low price at which the large quantities of caps and containers are sold, it is impractical to gauge and inspect individual caps and containers for correctness in size. Definite tolerances have been worked out for the glass containers which manufacturers endeavor to adhere to but it is not feasible to prevent some offsize containers from passing the inspectors.

Hence, it has been found that where the thread of the container is too low, the lug tends to ride over the thread to raise one side of the cap and impair the seal and where the thread is too high, the cap is not pulled down with sufficient force to form a tight seal. Excessive variations in either the lugs or the corresponding thread portions of the glass finish will result in a defective seal and spoilage of the contents of the package.

Another difliculty inherent in using lug caps to vacuum seal containers is that in the present practice when the lug caps are unscrewed, the lug cap is lifted from the rim of the container with uniform pressure at spaced points so that the full force of the vacuum within the container tends to hold the cap on the rim, thereby making it difiicult to unscrew such caps from the containers.

The present invention aims to eliminate these difficulties and has for one of its objects the provision of a lug capwhich has greater flexibility so as to form a perfect seal with containers having both high and low cams or threads.

Another object of the present invention is to provide a lug cap having increased resiliency and flexibility to permit it to grip the container thread in a more secure manner.

Another object of the present invention is to provide an improved method of making a lug cap adapted to accommodate a greater range of size variations in glass containers.

A further object of the present invention is to provide a sealed package which will permit the lug cap to be easily removed therefrom.

A further object of the present invention is to provide a container finish for the lug cap which will facilitate breaking the vacuum within the container.

Other and further objects of the invention will be obvious upon an understanding of the illustrative embodiment about to be described, or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice.

A preferred embodiment of the invention has been chosen for purposes of illustration and description and is shown in the accompanying drawings, forming a part of the specification, wherein:

Fig. 1 is a fragmentary sectional View showing a closure cap blank from which the lugs are to be formed;

Fig. 2 is a fragmentary perspective view of the blank shown in Fig. 1;

Fig. 3 is a fragmentary sectional view similar to Fig. 1 showing the step of forming the rolled edge or bead at the bottom of the skirt;

Fig. 4 is a fragmentary perspective view of the step shown in Fig. 3;

Fig. 5 is a fragmentary sectional View of the cap showing the step of pre-fiattening that portion of the head from which the lugs are to be formed;

Fig. 6 is a fragmentary perspective view of a portion of the closure showing the pre-flattened portions;

Fig. 7 is a fragmentary sectional View showing the step of turning the pre-flattened portion of the bead inwardly to form the lug;

Fig. 8 is a fragmentary perspective view of the closure showing a completed lug;

Fig. 9 is a sectional view of the finished cap after the sealing composition has been applied thereto;

Fig. 10 is an elevational view of a container finish laid out flat showing the container threads and the means for facilitating the removal of a lug cap therefrom;

Fig. 11 is a sectional view taken on line 1111 of Fig. 10 showing the lug cap in sealed position on the container; and

Fig. 12 is a sectional view taken on line 12-12 of Fig. 10 showing the position of the lug cap after it has been initially twisted to remove it from the container and showing the position of the lug during the breaking of the vacuum in the container.

Referring more particularly to Figs. 1 to 9 which show the method of making the cap according to the present invention, the first step is to stamp the hat-shaped blank 1, shown in Figs. 1 and 2, from a sheet of tin plate which is preferably coated or lacquered. The blank .1 comprises a cover portion 2 and a depending skirt 3. The cover portion 2 is provided with an annular groove 4 and a flexible panel 5which will indicate whether or not a vacuum is present in the container, as will be more fully described hereinafter. The space between the annular groove 4 and the skirt portion 3 forms a channel 6 which will receive a sealing composition to providea hermetic seal with the container.

The skirt portion 3 of the blank is provided with an outwardly extending brim portion 7 at its lower end. As shown in Figs. 3 and 4, this brim portion 7 is rolled into a bead 8, Preferably the bead 8 is rolled to such an extent that the raw edge of the bead 8. is adjacent the Ou side o t e Skirt po t o 3 an bel w t e upp p fi t s b ad- In order to obtain a more flexible lug, the bead 8 is pre-fiattened at spaced intervals as shown at 9 in Figs. and This pre-flattening operation is to permit the lugs to be of uniform thiekness. The pre-flattening of the portions 9 of the bead 8 may be accomplished in any well known or desired manner. Preferably the bead 8 is flattened at the portions 9 by pressure applied thereto, as indieated by the arrow in Fig. 5, in a lug forming machine. Preferably the inside of the cap rests against an annular cylindrical surface and pressure is applied at equally spaced points to flatten the lug portions. Along with this pre-flattening step the bead 8 may be, and preferably is, further rolled to form a tighter bead.

In forming the lugs, the pro-flattened portions 9 are turned inwardly as shown at 10 at about an 80 angle to the skirt portion 3. Preferably, in forming the lugs, the blank is on a roller with lug forming pockets having bottoms which limit and control the inward movement of the lug to insure uniformity. By flattening the lug portions laterally, the bead at the lug portion is flat and hence has its greatest resistance to deformation in a vertical direction; When the pre-flattened portion is turned inwardly an improved structural shape results. Pressure by the container thread portions tends to deflect the flattened portion in the direction of its smallest dimension rather than in the direction of a greater dimension. Thus, the turning in of the pre-flattened portions shifts the vertical plies of metal at an angle of about 80 to give greater flexibility to the lug when the container lug presses laterally against these plies. This flexibility permits the lug to flex downwardly under the pressure of the container lug as the closure is screwed home. Prefer ably, the length of the skirt of the closure is increased which adds further to the flexibility by giving greater leverage to the skirt portion.

After the lugs 10 are formed in the cap, the annular gasket 11 is applied to the channel 6 formed between the groove 4 and skirt portion 3. The gasket 11 may be any desired composition. Preferably, however, the gasket 10 is a flowed-in type gasket formed by flowing rubber or some synthetic compound in a plastic or liquid state into the channel 9 and permitting it to form the gasket 11 with suflicient plasticity to permit the rim of the container to imbed itself therein.

The resulting cap provides strong flexible lugs which will provide a secure seal with all permissible lug tolerances. If the thread is slightly lower than the permitted tolerances the lugs 11 have the necessary resiliency to be flexed down so as to prevent the lugs from riding over the thread and without breaking the glass. If the threads are higher than tolerances permit, the angularity of the lugs will permit them .to grip the threads to form a secure seal with the container.

The panel 5 the cap is used to determine whether or not a partial vacuum exists within the container. If a vacuum is present in a container the panel 5 will bulge downwardly due to the greater amount of pressure outside the container than within it; whereas, if a vacuum is not present, the panel will remain in the position shown in Fig.9 since the pressure within the container will be substantially-equal to the outside pressure. Various types of feeler mechanisms can be employed to bear against panel 5 to determine the presence of a vacuum in the container.

While the cap described above may be used with containers having the usual lug finishes, an improved finish therefor is shown in Figs. 10 to 12.

The container 20, shown in Figs. 1 0 to 12, has a glass finish 21 with a plurality of thread portions 22 below the rim 23. A shoulder 24 extends around the lower part of the neck 21. The thread portions 22 preferably have upwardly directed tapered ends 22a to permit a cap to be drawn down into contact with the rim 23 of the containers by engagement of cap lugs 10 with the underside 22b of the thread portions 22. It will be noted that the thread portions 22 are spaced from each other so as to permit the lugs 10 of a cap to be inserted between threads so that the lugs extend below the undersides 22b thereof. By twisting the gaps in one direction, the lugs engage the underside 22b of the upwardly directed ends 22a to draw the cap down until the gasket 11 is pressed against the rim 23 to effect a seal. The twisting of the cap is continued until the cap lugs engage stops 25. While the cap is being screwed on the container, the head space is usually filled with vapor to create a partial vacuum within the container.

The stops 25 are the forward faces of vertical portions 26 which are integral with and rearwardly of the thread portions 22. Each of the container lugs has an inclined cam surface 27 which is adapted to 'be engaged by the cap lugs 10 when the cap is twisted off to force the cap upwardly.

It will be noted that all of the rear edges of the inclined tail cam surfaces 27 are spaced in advance of the tip of the next rearwardly adjacent thread portion 22a with the exception of a single inclined release cam surface 27a which extends beneath the rearwardly adjacent inclined thread portion 22a for a considerable distance. This extended inclined release cam surface 27a provides the means for breaking the vacuum to facilitate removal of the cap. When the cap is twisted off, one of the lugs 10 engages this extended release cam surface 27a and as the lug rides on this cam surface the cap will be tilted at a single point as shown in Fig. 12 thereby admitting air into the container to break the Vacuum and facilitate removal of the cap. Since only a single inclined release cam surface 27a is provided, only one lug 10 will engage the cam surface 27a to thereby lift the cap a single point to break the vacuum. The unscrewing effort is much less where the cap is first raised at a single point than when it is lifted at several equidistant points.

In applying the cap to a container the cap is placed on the container so that the lugs enter between the spaced thread portions 22. When the cap is screwed on, the lug will engage the undersides 22b of the thread portions 22 and will be forced down until its gasket 11 is pressed against the rim 23. Continued twisting of the cap causes the lugs 10 to engage the stops 25. As shown in Fig. 11, the gasket 11 is in contact with the rim 23 throughout its circumference to provide a secure vacuum seal with the panel 5 bulging downwardly as shown exaggerated in Fig. 11. Since the lugs 10 are formed from pre-flattened sections 9 (Figs. 5 to 8) the final result is a more flexible lug which take up more variations in the thread portions 22a and will break less glass by reason of its flexibility, and will also take care of greater linear or gasket variations.

When it is desired to remove the cap from the container, the cap is twisted in the opposite direction. As shown in Fig. 12, one of its lugs 10 will engage the single extended inclined release cam surface 27a before the other lugs engage the remaining three cam surfaces 27. This permits the cap to be tilted at one point thereby permitting the gasket 11 to be forced away from the rim 23 at one point to thereby break the vacuum and permit easy removal of the cap.

:It will be seen that the present invention provides an improved glass finish and a lug cap which has greater flexibility so as to form a more perfect seal with both excessively high and excessively low container threads; and alsoprovides an improved method of making such lugs and an improved sealed package.

As various changes may be made in the form, construe? tion and arrangement of the parts herein without departing from the spirit and scope of the invention and without sacrificing any of its advantages, it is to be understood that all matter herein is to be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, 1 claim:

1. A sealed package comprising a closure cap having a cover portion and a depending skirt, screw lugs formed from the lower edge of the skirt and a sealing element within the closure for engaging the rim of the container to form a hermetic seal thereon in combination with a container having a plurality of thread portions for engaging said lugs respectively and having lift cam surfaces to engage and raise each of the lugs to the cap and in which one of said cam surfaces is effective to engage and raise its lug prior to the other cam surfaces becoming efiective upon their respective cap lugs.

2. A container having a plurality of thread portions to permit 9. lug cap to be screwed thereon into hermetic sealing relationship therewith, said thread portions being spaced from each other and being provided with rearwardly extending lifting cam surfaces, one of said cam surfaces being spaced from the front end of the thread portions a distance greater than the distance between the other earn surfaces and the front ends of their respective thread portions, whereby said one cam surface will engage said lug cap prior to the other cam surfaces and raise said lug cap at one portion thereof to break the vacuum and permit easy removal thereof.

3. A container as claimed in claim 2, wherein said one cam surface extends beneath the thread portion rearwardly adjacent thereto.

References Cited in the file of this patent UNITED STATES PATENTS 1,079,238 Hammer Nov. 18, 1913 1,849,522 Hammer Mar. 15, 1932 1,849,523 Hammer Mar. 15, 1932

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