US3448881A - Closure with means to control opening torque - Google Patents

Description

June 10, 1969 D. H. ZIPPER 3,448,881

CLOSURE WITH MEANS TO CONTROL OPENING TORQUE Filed May 2, 1967 Sheet of 2 f". j] I v W V INVENTOR f O ALD H.ZIPPER June 10, 1969 D. H. Z I PPER I 3,448,831

CLOSURE WITH MEANS T0 CONTROL OPENING TORQUE Filed May 2, 1967 Sheet 2 of 2 I INVENTOR O DONALD H.Z/PPER I BY MW,

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United States Patent 3,448,881 CLOSURE WITH MEANS TO CONTROL OPENING TORQUE Donald H. Zipper, Western Springs, 111., assignor to Continental Can Company, Inc., New York, N.Y., a corporation of New York Filed May 2, 1967, Ser. No. 635,439 Int. Cl. 365d 33/00 US. Cl. 215-40 11 Claims ABSTRACT OF THE DISCLOSURE A package including a container and a closure cap of the press-on turn-off type having means to prevent settling of the cap onto the container finish after application thereby to prevent an increase in removal torque. One means to prevent increase in torque removal consists of forming the top panel of the shell of the cap with a debossment or groove which, on the underside, forms a ridge axially opposed to the top rim of the closure. If continuous, the ridge defines with the rim a thin gasket area serving to reduce oxygen permeation through the gasket.

This invention relates to improvements in packages of the typewherein a press-on turn-off type cap is applied to a container finish. More specifically, the present invention relates to improvements in the torque removal characteristics in packages of the type illustrated and described in U.S. Patents Nos. 3,270,904 and 3,285,452.

In the above-identified patents is disclosed a package of the type formed by applying a closure cap to a container finish by a press-on movement without intentional rotation. Prior to application, the closure cap is linedwith a suitable gasket compound, such as a foamed plastisol or the like which, with time and/ or heat, forms a cam-off means to co-operate with threads or a cam-off means on the container to permit removal of the cap by rotation.

In one preferred form of package, the container finish is of a frusto-conical shape and has cam-01f means such as threads embossed thereon. The co-operating closure cap is formed with a top panel and depending skirt and a lining of gasket material which, on capping, conforms to the shape of the container finish. One product which is commonly packed in this type of package is baby foods. In one method, subsequent treatment includes processing the filled and capped containers in high temperature and pressure retorts. Another method of packaging is to fill the package with the contents in a heated condition, and thereafter apply the cap, permitting the package to cool. After considerable testing, it was discovered that packages formed by this latter process behaved differently in that over several months, the opening torque required to remove the cap increased beyond the preferred range of 20 to 30 inch pounds in a common baby food closure cap of 53 mm. size. Immediately after filling and capping, the opening torque was in the preferred range, however, over a prolonged period, regardless of the gasket formulation, the opening torque seemed to rise well beyond the preferred range. Some gasket formulations had a lesser torque increase than others, but even with the best of all the gasket compositions tested, the opening torque values increased to a point Where they were beyond the preferred range Within four to six months of the date of capping. This was undesirable, as the presson turn-off closure cap is most suitable for packaging applications. If consumer good will was not to be lost, opening torques must be consistent to permit the average housewife to remove the cap, but yet the closure cap must fit with suflicient tightness to prevent oxygen permeation or leaking.

The present invention relates to a novel means for preventing the increase in removal torque which was discovered to be attributable to the settling of the cap on the finish. The present invention is directed to a means which prevents such settling of the cap onto the finish and, in one embodiment, also provides a means which serves to reduce the thickness of the gasket material and thereby reduce the cross-sectional area through which oxygen may permeate. One form of the means which prevents settling may consist of a continuous groove formed in the top panel of the cap and presenting on the underside a continuous ridge which is disposed in axial opposition to the rim of the container finish. In this design, the cross-sectional area of the gasket material between the ridge and the rim of the container finish is minimized to provide good resistance to oxygen permeation. Where oxygen permeation is not a problem, settling of the gasket on the finish may be prevented by forming spaced dimple means in the top panel of the cap which present raised ridges at spaced locations on the underside of the cap. These ridges are positioned in opposition to the rim of the container finish and co-operate with the finish through a thin layer of gasket material to prevent settling of the cap on the finish, effectively to reduce torque rise beyond the preferred range. A greater appreciation of the features and advantages of the present invention may be had upon considering the objects achieved and the accompanying detailed description of preferred embodiments.

It is an object of this invention to provide a new and improved closure cap of the type having a gasket means for thread forming and in which is provided a means to prevent increases in removal torque after press-on application of the cap to a thread forming finish of a container.

It is a further object of this invention to provide a new and improved package including a press-on type of closure cap and container having a thread forming finish wherein the closure cap is provided with means to prevent increase in removal torque, which means is also effective to reduce the total cross-sectional area of gasket material between the cap and container and thus reduces oxygen permeation through the gasket.

It is a still further object of this invention to provide a new and improved means to prevent increase in removal torque in a package formed by applying a closure of the press-on turn-off type to a container finish which has thread means co-operating with gasket means in said cap to provides means to permit removal of the cap by rotation.

Objects other than those specifically set forth will become apparent when reference is made to the following descriptions and accompanying drawings wherein:

FIGURE 1 is an enlarged diametric cross-sectional view of a shell of a closure cap embodying the present invention;

FIGURE 2 is a top plan view of the shell of FIGURE 1 on a slightly reduced scale;

FIGURE 3 is an enlarged cross-sectional view of the shell of FIGURE 1 after it has been lined with gasket compound;

FIGURE 4 is a half-sectional view of the closure cap of FIGURE 3 after application to a container shown in fragmentary cross section;

FIGURE 5 is a top plan view of a modified form of shell; and

FIGURE 6 is an enlarged fragmentary cross-sectional view taken generally along the line '66 of FIGURE 5.

Referring now to FIGURE 1, reference numeral 10 indicates a body or shell having a top panel portion indicated generally at 11 and a depending skirt portion designated at 12. The cap bodies or shells are stamped from suitably coated tin plate or the equivalent. Generally, the plate is enameled on the exterior and the interior may be enameled or coated with a known lacquer formulation to form a protective coating on the underside of the shell, as well as to provide an attractive appearance.

The bottom edge of the depending skirt 12 is rolled, as at 13, to reinforce the edge, provide a neat appearance and turn in the sharp edge left by the stamping operation, hiding it for consumer safety and corrosion protection. The skirt 12 may be formed to any desired shape, such as the one shown, or a frusto-conical shape, cylindrical shape or the like. In the illustrated embodiment, the middle portion 14 of the skirt is of frusto-conical shape, while the upper and lower portions are generally cylindrical, as indicated at 15 and 16.

As seen in FIGURES 1 and 2, a continuous annular shoulder 17 is formed in the top panel portion .11 and forms one of the side walls of a channel 18 (FIGURE 1). The outer side wall of the channel 18 is formed by a rounded shoulder 20 formed at the intersection of the skirt 12 with the top panel 11. Within the channel 18 is formed a continuous annular groove 21 which, when viewed from the underside of the top panel 11, presents a continuous raised ridge 22 extending in the direction of the skirt. The annular groove 21 may be formed at the time the closure cap is stamped to the configuration'shown.

The shell 10 is lined with gasket compound around the entire inner surface of the skirt 12 with the gasket material extending onto the top panel 11 and substantially filling the channel or groove 18 in the manner shown at 23 in FIGURE 3 and, thus, forming a closure cap indicated generaly at 24. The gasket material 23 may be deposited by any suitable means, such as metering a measured quantity while slowly rotating the shell 10 in an inverted position or the equivalent. If required, it may be subsequently molded to any desired shape. The gasket composition may be of any suitable type, however, the problem outlined above was most prevalent in gasket compositions formed from foamed or puffed plastisols.

In FIGURE 4, reference numeral 30 indicates a package which is formed by applying the closure cap 24, shown in FIGURE 3, to a container 31. The container 31 may be of any suitable type, such as a glass jar having a finish 32 which includes threads 33 embossed on the outer circumference 34. At the upper end of the finish, the container mouth is defined by a rim 35 which is adapted for reception into the gasket channel 18. While a threaded container finish is shown, it may include cam-off means of any suitable type such as is illustrated and described in the above-mentioned patents. As torque removal due to cap settling or the like is only experienced in closures in which threads or cam-oft means are formed in the gasket, the present invention is mainly applicable to this field.

The closure cap 24 is applied to the container finish 32 by means of a press-on motion which causes the gasket material 23 to deform and assume the configuration shown, conforming to the shape of the circumference or external portion of the container finish and top rim 35. In this manner, threads 36 are formed in the gasket compound which, with the passage of time and/or application of heat, become sufiiciently rigid to permit subsequent re moval of the cap by rotation.

The ridge 22 projects toward the rim 35 and defines a thin gasket area 37. Ideally, from the standpoint of preventing cap settling, the ridge 22 should actually touch the rim 35, however, another factor, that of providing protection against impacts, dictates that a thin film covers the ridge to act as a cushion. Since the film is very thin in this area, settling of the cap with the attendant increase in torque removal is prevented. As is evident, the gasket material on opposite sides of the ridge 22 is of much greater thickness, with the intermediate material being very thin as shown at 37. In the absence of the ridge 22, the greater gasket thickness would permit substantial compression or settling of the cap with the passage of time, with an attendant increase in removal torque. The annular ridge 22 forms a substantially rigid means, which when acting through the less rigid thin gasket material 37, prevents cap settling after application. It has been discovered that the torque required to remove the closure cap 24 will remain substantially constant when such means is provided.

The thin gasket material at 37 between the ridge 22 and rim 35 is of reduced cross-sectional area and, hence, the oxygen permeation is minimized. This is particularly important in packaging products such as strained meats or the like, which require an extremely low leak-rate cap due to the products sensitivity to oxygen even in very small amounts. The novel co-operation of the ridge 22 and rim 35 to produce a narrow or thin gasket area materially reduces the leak-rate of the present cap when compared to prior art caps of comparable types.

A modified form of the invention is illustrated in FIGURES 5 and 6 and includes a shell 40. This shell 40 is of similar shape to the shell 10 shown in FIG- URE 1, however, is provided with a modified form of means to prevent the increase in cap removal torque in the form of a series of dimples 41 angularly arranged about the periphery of the top panel in the middle of the gasket channel 42. Any desired number of dimples may be provided, being dictated by the particular application, and they may be in the form of debossments formed during stamping and shaping of the shell. As seen in FIGURE 6, the dimples 41, when viewed in cross section, present a ridge 43 which is of similar shape'to the ridge 22, however, is not continuous. The shell 40 is applied to the container finish .and functions to prevent increase in torque removal in the manner described above with respect to the closure cap 24, however, because of the lack of continuity, does not resist oxygen permeation as described in the embodiments of FIGURES 1-4.

Upon a consideration of the foregoing, it will become obvious to those skilled in the art that various modifications may be made without departing from the invention embodied herein.

I claim:

1. In a package of the type wherein a cap having a top panel and a circumferentially continuous depending skirt is applied to a container having a finish including thread forming means thereon and terminating in an upwardly facing top rim, said depending skirt of said cap surrounding said finish in spaced relation thereto and said top panel being disposed in axially opposed spaced relation with said rim, a layer of plastisol gasket material adhered to said skirt and extending onto said top panel of said cap, said gasket material having threads formed therein by said thread forming means on said container when said cap is applied to said finish thereby permitting removal of said cap by rotation relative to said container, the improvement which comprises means to prevent the increase in cap removal torque after application of said cap to said container, said means including means to prevent settling of said cap on said container finish after capping thereof due to gradual deformation of said gasket material in engagement with said top rim whereby increase in said removal torque is prevented.

2. The improvement in packages as defined in claim 1 wherein said means to prevent settling of said cap on said finish comprises a continuous ring forming a ridge on the underside of said cap, said continuous ring being more rigid than said gasket material, said ridge being disposed in closer proximity to said finish than the immediately adjacent part of said cap whereby said continuous ring will prevent settling of said cap on said finish and thereby prevent increases in the opening torque of said cap.

3. The improvement in packages as defined in claim 1 wherein said means to prevent settling of said cap on said container finish includes a continuous groove means formed in a top panel portion of said closure cap and forming a continuous annular ridge projecting toward said container finish, said gasket means being interposed between said continuous ridge and said container finish to provide a section of reduced thickness and thereby reduce the eifective cross-sectional gasket through which oxygen may permeate.

4. The improvement in packages as defined in claim 1 wherein said means to prevent settling of said cap on said container finish after capping thereof comprises dimple means formed in said cap and projecting toward said container finish, said dimple means being provided at spaced locations around said closure cap and forming spaced ridges on the underside of said cap for disposition in closely spaced relation to said finish to prevent settling of said cap and thereby maintain opening torque thereof substantially constant over a prolonged period of time.

5. The improvement in packages as defined in claim 3 wherein said ridge is formed on the underside of said cap by deforming said top panel in an area which is axially opposed to said upwardly facing top rim.

6. The improvement in packages defined in claim 4 wherein said ridge on said dimple means is formed by a plurality of debossments formed in said top panel adjacent said circumferentially continuous skirt.

7. The improvement in packages as defined in claim 1 wherein said gasket material is a foamed plastisol.

8. A closure cap of the press-on turn-off type, said closure cap including a shell having a top panel portion and a continuous depending skirt portion, an endless layer of plastisol gasket material lining at least a part of said shell and being adapted to be reformed to conform to the shape of a container finish on press-on application thereto whereby thread means permitting removal of said cap by rotation will be formed, and means on said cap to prevent settling of said cap on said finish due to gradual deformation of said gasket material in engagement with said top rim and thereby preventing .an increase in torque removal after application of said cap to said container finish.

9. The closure cap of claim 8 wherein said means to prevent settling of said cap on said finish thereby preventing an increase in torque removal after application of said cap to said container finish comprises a continuous annular ridge formed on the underside of said top panel for disposition in axially opposed relation with said container finish, said gasket material covering said ridge in a thin layer to reduce oxygen permeation and prevent settling of said cap onto said container finish.

10. The closure cap of claim 8 wherein said gasket material is a foamed plastisol.

11. The closure cap of claim 8 wherein said means to prevent an increase in torque removal comprises ridge means in a gasket channel formed in said top panel of said shell, said ridge means being positioned for axial opposition with a top rim of said container finish to prevent settling of said cap after application thereto.

References Cited UNITED STATES PATENTS 2,085,934 7/1937 Von Till 21S40 2,848,131 8/1958 Ward 215-39 3,142,401 7/1964 Foss et al. 21540 3,270,904 9/1966 Foster et a1. 215-43 JOSEPH R. LECLAIR, Primary Examiner.

U.S. Cl. X.R. 215-43

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