IL44816A - Tear-off bottle closure - Google Patents

Abstract

1464577 Metal closure AMERICAN FLANGE & MFG CO Inc 13 May 1974 [23 May 1973] 21045/74 Heading B8T A metallic closure has a circular cap portion 2 stiffened by means of an annular embossment 11 which itself surrounds a circular embossment 13 the cap being integral with a cylindrical skirt 4, two score lines 6 passing across the surface of the cap and skirt and defining between them a tear strip 7 which extends in a direction perpendicular to the grain structure of the cap material, the score lines being ruptured at the time of opening by means of a pull tab 8. A gasket 10 is secured to the junction between cap and skirt. [GB1464577A]

Description

ΡΌΡ37 W7JTJ "UO TEAB-OPP BOTTLE CLOSUBE CONVENIENCE CLOSURE Abstract of the Disclosure A lightweight metal closure cap for containers having a pa of score lines extending acros s the cap skirt and top portions defining a tear strip therebetween including a depending ring pull member extending radially from the skirt free edge. An annular reces s ed embos sment formed in the cap top portion and an annular sealing gasket formed in situ within the cap interior.

Background of the Invention With the increas ing acceptance of tear- off convenienc e closures, particularly in the "wide mouth" beverage bottle field, further refinement of the tear- off s ealing concept has been sought. Such refinement stems from the desire to evolve a lightweight metal tear- off closure having improved structural characteristics as compared to present standards . In those s ituations where severe abuse is encount ered, due to rigorous handling and storage conditions, the structural characteristics of the closure become increas ingly acute. One such area of concern involves the rigidity of the closure top panel which must, of neces s ity, flex to a certain degree under the influence of internal pressure. At the same time, however, in keeping with accepted sealing principles, the closure gasket must be constantly held in tight sealing contact with the underlying bottle neck regardles s of the severity of the top panel flexure.

It has also been found that the presence of any warpag e quality as the gasket is formed in situ within the closure interior. g Thus the ability to maintain the closure top panel in a flat plane is an important factor in achieving the precise gasket positioning essential for maximum sealing effectiveness.

The tear-off convenience closure construction disclosed by the instant invention embodies the improved structural characteristics sought after and achieves a degree of sealing efficiency, coupled with ease of opening, heretofore unattainable. This has been accomplished through the provision of an annular recessed embossment formed in the closure top panel which serves to add a highly desirable degree of rigidity to the overall closure. As a result, excessive flexure of the top panel due to severe use conditions is minimized with the closure gasket tightly anchored to the underlying bottle lip regardless of internal pressure variations. In addition, the embossed top panel eliminates any warpage that might otherwise be present, permitting the precise application of a semi-liquid gasket compound about the periphery of the top panel interior surface.

It is, accordingly, a principal object of this invention to provide an improved lightweight metal tear-off convenience closure for "wide mouth" beverage bottles.

Another object is to provide an improved tear-off closure having a depressed embossment in the top panel specially formed to minimize flexure and warpage of the closure.

Other and more detailed objects will be in part obvious and in part pointed out as the description of the invention, taken in conjunction n a raw ng: Fig. 1 is a perspective view of the closure cap in accordance with the invention: Fig. 2 is a vertical s ection thereof; Fig. 3 is an enlarged fragmentary vertical section thereof; Fig. 4 shows a closure cap in pos ition on a spinning chuck for receiving the gasketing compound; Fig. 5 is an enlarged fragmentary vertical s ection of the closure cap applied to a bottle in a pres surized condition; and Fig. 6 is a view s imilar to Fig. 5 but showing the pr ior art condition.

The closure cap of the invention, generally indicated by numeral 1 and as shown in Figs . 1 and 2, is formed but of lightweight sheet metal and is s een to compris e a circular top panel 2 surrounded by a radius ed juncture portion 3 from which a cylindrical skirt 4 depends terminating in a lowermost free edge 5. A pair of score lines 6, formed in the cap interior surface, extend acros s the cap skirt in substantially parallel relationship and then flare outwardly away from each other in their extent acros s the cap top panel defining a tear strip 7 therebetween. It should be noted that exterior scoring and scoring having other configurations could also be employed. A ring pull portion 8 is formed as an integral part of the tear strip 7 and extends away from the skirt edge 5. A pair of notches 9 are formed at either s ide of the tear str ip at the skirt edg Turning to Fig. 3 which shows the cap top panel 2 in greater detail, it is seen that a major recessed embossment 11 is formed therein which extends radially outwardly to the radiused juncture portion 3. The major embossment.il has been found to yield the desired degree of rigidity, as discussed further hereinafter, if formed to a depth of approximately one and one half times the thickness of the sheet metal from which the cap is formed and no deeper than three times the metal thickness as a maximum. It has also been found the step between the uppermost surface of the cap and the embossed surface 11 should be a very gradual incline as indicated at 12 in order to minimize the inherent resistance to tearing presented by a change in the tearing plane. To further strengthen the cap, a minor recessed embossment 13 is centrally disposed within the major embossment 11 and defined by a gradual step 14.

As stated hereinbefore, several advantages have been found to arise as a result of forming the above described embossed formation in the cap top panel. Firstly, the embossing adds a substantial degree of rigidity and flatness to the cap uppermost surface, thus eliminating any warpage that might otherwise be introduced during the cap manufacturing process. As shown in Fig. 4, the sealing gasket 10 is formed in situ within the cap interior by injecting a semi-liquid gasketing compound through a nozzle 15 into the cap as it is spun on a rotating lining chuck 16. It can readily be seen that the degree of flatness in the cap top panel has a direct effect on the precise placement and formation of the sealing gasket 10.

Another advantage offered by the particular embossing employed is illustrated in Fig. 5 wherein the closure cap 1 is shown a lied to the neck of a bottle 17 containin an internal ressure typical of that normally contained in a beer or soft drink bottle.

Fig. 6 illustrates the same condition as Fig. 5 but instead incorporates the prior art closure cap 20 having a flat top panel 21 surrounded by a radius ed juncture portion 22 a cylindrical skirt 23 and including a s ealing gasket 24. Looking first at the prior art cap 20 in Fig. 5, it is clearly shown how the doming of the cap top panel 21 due to internal pres sure buildup tends to lift the gasket portion 24a away from the underlying glas s surface, thus introducing the pos s ibility of a leakage path between the gasket and the bottle neck . In the invention construction of Fig. 5 the same pres sure buildup has the harmles s effect of caus ing only the embos sed portion of the cap top 2 to dome upwardly. Accordingly, while doming in the prior art cap caus ed the top panel to flex from the radius ed portion inwardly, in the invention cap the major embossment 1 1 flexes from the step 12 inwardly, leaving the radius ed juncture panel and the underlying gasket 10 relatively undistrubed. Tight compres s ion of the s ealing gasket throughout its extent, as above des cribed, as sures maximum effectiveness for long term carbonation retention.

In addition to generally strengthening the cap s o as to advantageously withstand the abuse frequently encountered due to s evere handling and storage conditions, the embos sment construction permits the cap to be fabricated from sheet metal having a microscopic grain structure running perpendicular to the skirt scor e lines 6 as indicated by the arrow at numeral 7a in Fig. 2. In the manufactur e of prior art caps , it was neces sary to have the metal grain running in a direction parallel to the skirt scoring in order to prevent However due to the embos s ed construction disclosed herein, sufficient rigidity is built into the cap during the manufacturing proces s to eliminate the warpage that had heretofore neces s itated orienting the grain parallel to the skirt scor ing. Since running the metal grain perpendicular to the skirt scoring minimizes fracturing of the thin layer of metal remaining behind the s coring, a stronger cap and one having improved tearing characteristics results .

Having described my invention, what we claim is as follows : behatt

Claims (1)

1. , A tear-off convenience bottle closure formed of lightweight sheet metal comprising a circular top panel surrounded by a depending cylindrical skirt terminating in a lowermost free edge, a radiused juncture portion connecting said top panel and said skirt, a pair of score lines extending across said cap skirt in substantially vertical parallelism and continuing across said top and defining a tear strip therebetween, said tear strip, including an integrally formed pull member extending away from said skirt free edge, a sealing gasket affixed to said juncture portion, characterized by the combination, of stiffening means formed in said top panel . and said sheet metal having a grain structure running in a direction perpendicular to the score lines in the skirt portion of said closure. FOR AND ON BEHALF O APPLICANT ; ^