FIELD OF THE INVENTION
- BACKGROUND OF THE INVENTION
This invention relates to closures, and more particularly to fluted crown caps for sealing a bottle opening
Crown caps are well known for sealing bottle openings. Conventional crown cap configurations include a circular top, a circular skirt depending downwardly from a periphery of the top, and a downwardly and radially outwardly extending flange extending from a periphery of the skirt. The skirt generally has flutes or serrations formed therein to enhance capping and gripping on a bottle finish.
For example, U.S. Pat. No. 5,458,253 describes a conventional crown in which substantially trapezoidal-shaped troughs or depressions are formed between raised flutes. The industry is the United States is presently standardized on a configuration employing 21 flutes.
Crown caps, originally developed for opening by deforming upon actuation by a lever opener, are often configured for twisting off by employing threads formed on the finish of the bottle. Such twisting, in some circumstances, requires a relative high amount of opening torque and may be difficult to open or uncomfortable with respect to a user's hand.
- SUMMARY OF THE INVENTION
Also, some crown cap configurations are subject to gearing, which is the engagement and interlocking of the flange of a crown cap with the opposite facing flange of another crown cap during shipping or handling thereof. In this regard, because crown caps are often shipped loose, two adjacent, oppositely facing crown caps may maneuver into a position in which the underside of a trough of the first cap may (in some configurations) become aligned and inserted into the underside of a serration of a second cap. If the first and second caps become engaged or locked together, the two-crown cap combination has the potential to jam capping equipment or otherwise be detrimentally affect the capping or crown-cap handling process.
A crown cap for applying to a beverage bottle comprises a circular top member; a skirt depending downwardly from a periphery of the skirt; and a flange extending from a periphery of the skirt. The flange includes plural, substantially radially oriented repeating potions, which include circumferentially spaced apart, upwardly extending flutes and land portions disposed between each flute. Each land portion has a circumferential dimension, which is measured at a perimeter of the flange, that is greater than a distance between the flat portions, thereby preventing gearing engagement of oppositely oriented crowns.
Each flute includes a pair of upwardly-extending, opposing flute sidewalls that meet at an uppermost portion thereof to form a crest. A lower portion of each flute sidewall extends downwardly to couple with a land portion. Preferably, at least a portion of each land is flat. The invention, however, is not limited to flat lands, but rather encompasses any shaped land, as explained more fully below.
Each flute preferably is formed in an inverted-V shape that forms an angle that preferably is between 21 and 51 degrees, more preferably, between 26 and 46 degrees, even more preferably between 31 and 41 degrees, and, in the embodiment illustrated in the figures, approximately 36 degrees.
BRIEF DESCRIPTION OF THE DRAWINGS
The crown cap preferably has 27 flutes, which, in accordance with the flute configuration described herein, is believed to enhance a user's ability to grip the crown cap while at the same time making it more comfortable to a user's hand during the twist-off process. An equation is provided governing the configuration of the lands relative to the configuration of the flutes to prevent or substantially reduce engagement or gearing between oppositely disposed, crown caps in circumstances where such crown caps are loose.
FIG. 1 is a top perspective view of a crown cap illustrating the present invention;
FIG. 2 is another top perspective view of the crown cap shown in FIG. 1;
FIG. 3 is a bottom perspective view of the crown cap shown in FIG. 1;
FIG. 4 is another bottom perspective view of the crown cap shown in FIG. 1;
FIG. 5 is a top view of the crown cap shown in FIG. 1;
FIG. 6 is a bottom view of the crown cap shown in FIG. 1;
FIG. 7 is an enlarged view taken through line 7-7 in FIG. 5;
FIG. 8 is a side view of the crown cap shown in FIG. 1; and
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
FIG. 9 is an enlarged view taken of a portion of FIG. 8.
A crown cap 10, as illustrated in the perspective views shown in FIGS. 1 through 4, includes a substantially circular top member 12 about which a circumferential skirt 14 downwardly depends. Skirt 14 smoothly merges into a downwardly and radially outwardly extending flange 14. Flange 14 is divided into undulating, repeating portions including flutes 18 and lands 20. Preferably, the repeating portions are circumferentially evenly spaced apart such that each flute 18 is identical to all other flutes around the circumference of crown cap 10, and each land 20 is identical to all other lands around the circumference of crown cap 10.
As best shown in FIG. 7, flange 16 extends at a flange angle, measured from a horizontal plane, that is approximately 27.25 degrees. As best shown in FIGS. 3, 4, 8, and 9, each flute 18 includes a crest 22 that is formed by a pair of opposing flute walls 24. A lowermost portion of each flute sidewall 24 preferably smoothly merges with a land 20.
Preferably, the land portions 20 are flat (as shown in the figures), or are substantially flat with slightly upturned edges (in side view) that smoothly merge with the lowermost portions of the flute sidewalls. The present invention is not limited to such flat or substantially flat lands, but rather encompasses lands of any shape (in side view) that comport with the broad aspects of the present invention.
The juncture between flutes 18 and lands 20 are formed by a tooling radius R, which is indicated in FIG. 9. The magnitude of radius R may be chose according to conventional tooling considerations.
As described above, some crown cap configurations may be detrimentally coupled together when oppositely oriented crown caps are aligned such that a land of a first crown cap is inserted into the flute of an adjacent crown cap.
Crown cap 10
prevents such gearing because land 20
has a peripheral dimension that is greater than the opening dimension of the underside of the flute 18
. Such configuration may not always be optimum, however, and thus the land 20
may have a peripheral dimension that is less than the opening at the underside of flute 18
by a dimension that depends on the starting plate thickness and the radius at which flute sidewalls 24
merge into land 20
. In particular, the circumferential, peripheral land dimension A (illustrated in FIG. 9
) may be governed by the following equation:
- where D is the outside diameter of the base of the crown cap,
- N is the number of flutes,
- G is the starting plat thickness (generally shown in FIG. 7), and
- R is the tooling radius (generally shown in FIG. 9).
A crown cap for which land dimension A is equal to or slightly less than the right side of the above equation would enable a land to enter the underside of an opposing crown cap, but such a land would not likely engage or gear together with such an opposing crown cap.
The crown cap illustrated in the figures has twenty-seven flutes 18, which departs from the current standard that is set at 21 flutes. A crown cap with twenty-seven flutes, it is believed, would generally enable a user to more effectively grip crown cap 10 (compared with prior art 21 flute caps) for crew-type opening crown caps, and would generally provide a better feel for the user because the magnitude or height of each flute in crown cap 10 would likely be less than in conventional crown caps. The present invention is not limited to crown caps having flutes with lower heights than the prior art, and this discussion merely points out one of the advantages of a particular configuration to which crown cap 10 is suitable.
The actual configuration of the flutes would depend upon the particular configuration of parameters, including (in addition to the number of flutes), diameter of the blank from which the crown cap is formed, choice of material, thickness of the sheet from which the crown cap is formed, and like parameters, as will be understood by persons familiar with conventional crown cap configuration, engineering, and manufacturing. In the preferred embodiment shown in the Figures, crown cap 10 is formed of 78 pound, conventional tin plate. The overall diameter (that is, across the outermost points of flange 16 as, for example, shown in FIG. 7) is 1.263 inches, which is conventional.
For the configuration illustrated in the Figures, and as indicated in FIG. 9, flute sidewalls 24 are oriented at an angle alpha that is approximately 36 degrees. The present invention, however, encompasses flute angles alpha between 21 and 51 degrees, more preferably between 26 and 46 degrees and even more preferably 31 to 41 degrees.
The actual height of a flute configured according to the present disclosure may be determined according to the factors discussed above, as will be understood by persons familiar with conventional crown cap design in light of the present disclosure. Furthermore, the configuration of the dies and related manufacturing processes for forming crown caps made in accordance with the present invention, and the configuration of the machinery to apply crown caps made in accordance with the present invention to conventional bottles, will be apparent to persons familiar with crow cap design and implementation.
The present invention has some advantages relating to comfort with respect to twist-off crown caps, but the invention is not limited to crown caps only for such twist-off use. Moreover, the invention is illustrated by the present disclosure, which is not intended to be limiting. Rather, the present invention encompasses all crown caps configured according to the broad principles provided herein, as will be understood by persons familiar with crown cap design.