US 3642167 A
A flexible closure is provided with a flexing groove in the closure top and a sealing groove in a downwardly depending skirt adapted to conform substantially to the opposing surface of a beaded container rim to form a seal with the beaded rim although the closure is considerably flexed by a container of greater than optimum diameter.
Claims available in
Description (OCR text may contain errors)
United States Patent Kinney 1 Feb. 15, 1972  CONTAINER CLOSURE 3,269,588 8/1966 Ruekberg ..220/60 R  Inventor: Alfred W. Kinney, Kansas City, MO. FOREIGN PATENTS OR APPLICATIONS [731 Assignw Phillips Pelmkum Company 686,402 5/1964 Canada ..220/60 R 22 i July 20, 1970 865,039 4/ 1961 Great Britain ..215/41 ] Appl' 56,374 Primary Examiner-George E. Lowrance Attorney-Young and Quigg  [1.8. CI. ..220/60 R, 215/41  Int. Cl. ....B65d 43/10, 865d 41/22 ABSTRACT  Field of Search ..220/60 R; 215/41; 229/43 A flexible closure is provided with a flexing groove in the sure top and a sealing groove in a downwardly depending skirt  References Cited adapted to conform substantially to the opposing surface of a UNITED STATES PATENTS beaded container rim to form a seal with the beaded rim although the closure is considerably flexed by a container of l I 1 5 Blakeslee ..2 l greater than optimum diameten 2,586,775 2/1952 Benner ..215/41 X Cserny ..220/60 R x 5 Claims, 6 Drawing Figures PATENTEUFEB15 I972 3.64216? INVENTOR.
A. W. KINNEY A T TORNE VS CONTAINER CLOSURE This invention relates to a formed closure for a container. In one aspect, it relates to a closure made of flexible material. In another aspect, it relates to a reusable closure for a container. In still another aspect, it relates to a closure for a container having a beaded rim. In yet another aspect, it relates to a closure that forms a moisture retentive seal with a container. In yet another aspect, it more specifically relates to a closure suited for retaining the moisture content within a dairy product container.
A great number of container closures have been formed of flexible sheet material, such as synthetic therrnoplastics. Some of these closures have been of a stopper type, fitting inside the bore of a container opening. Others have been of the covering type, which fit over the outside of the container opening and seal around a head or other sealing device provided on the exterior of the container opening. This invention is concerned with the latter type of closure.
The design of conventional snap-on coverall closures, particularly the standard injection molded polymer closures, is such that only line contact is achieved when the closure contacts the container brim diameter. A line contact seal is unsatisfactory in many applications because it does not provide a good hermetic seal so that products with a high moisture content lose 1 percent or more of their moisture in a 7-day period when packed in such a container. Unfortunately the limitations of production equipment and production material characteristics make it impractical to hold dimensional tolerances on the brims of thermoformed plastic containers within limits that assure satisfactory sealing of conventional snap-on coverall closures. Even within practical tolerance limits as the diameter of the brim of the container increases to its upper tolerance limit the closure skirt angles outward moving the line of contact between the closure and the container brim toward the top of the rolled brim or beaded rim of the container thus reducing the effectiveness of the seal.
It is therefore an object of this invention to provide a container with a closure with improved moisture retentive sealing qualities. It is a further object of this invention to provide an economical, tight sealing closure for high moisture content product containers such as dairy product containers. It is a further object of this invention to provide a flexible closure that is reusable. It is a further object of this invention to provide a closure that is stackable. It is a still further object of this invention to provide a closure that allows a wider tolerance of size differential in container closures and container brim diameter without reducing sealing qualities.
These and other objects are achieved by the container closure of our invention as described in this specification, the drawings and the appended claims.
According to the invention a container closure is made of flexible material and is adapted to have the sealing groove on the inside of the downwardly depending skirt conform substantially to the opposed surfaces of the beaded rim of the container to which it is fitted so that on flexing the container closure, the sealing groove and flexing groove act in conjunction to continue conformation of the container closure groove to the opposed surface of the beaded rim of the container to which the closure is fitted.
The closure of the invention can be readily seen by reference to the drawings,
FIG. I shows two closures of the invention in stacked relationship.
FIG. 2 shows the sealing groove of the invention applied to the beaded rim that it was contoured to fit.
FIG. 3 shows an alternativecontour for the closure.
FIG. 4 shows a conventional coverall closure in perfect alignment with a beaded rim.
FIG. 5 shows a conventional coverall closure as aligned with a beaded rim of a container the diameter of which is approaching the maximum tolerable.
FIG. 6 shows a closure of this invention in alignment with a beaded rim of a container the diameter of which is ap proaching the maximum tolerable.
Referring now to FIG. 1, the closure of our invention which is a one-piece closure, preferably made by thermoforming can be seen. The distinctive feature of the closure of this invention is the conformation of the sealing groove inside the downwardly depending skirt to the contour of the beaded rim of the container to which the closure is to be attached. The closure is formed having a central discoidal portion 11. At its perimeter, this discoidal portion is provided with an upstanding wall structure in the shape of a conical frustum of increasing diameter from bottom to top 12 which terminates at its top in an outwardly extending annular ring portion increasing in thickness towards the outer perimeter 14 and forming in conjunction with the conical frustum portion an outwardly extending groove on the inside of the closure 15 which serves as a flex point in the closure top. In the outer extremity of the annular ring 13 in the area of increased thickness 14 is a downwardly depending skirt 16. The skirt is of generally decreasing thickness from top to bottom and contains in its inside wall a sealing groove 17 which is conformed to the contour of the beaded rim of the container it will be used to close.
In the embodiment shown in FIG. 1, the skirt portion is offset from the outer periphery of annular ring portion and depressed from the upper edge of the annular ring portion to produce a groove on the upper outer perimeter of the closure which aids in the stacking of the closures. The closures are stacked by fitting the lower extremity of the skirt portion of one closure into the stacking groove of another closure.
FIG. 2 shows a closure of my invention applied to a container opening. The complete conformation of the closure seal groove 17 to the contour of the surface of the beaded rim of the container 19 is shown in this embodiment. In another embodiment shown in FIG. 3, the sealing groove 17 is shaped so that only the lower half of the sealing groove forms the contour of the are described by the radius of the curvature of the beaded rim of the container 19. The upper portion of the sealing groove may be squared off as illustrated 20, or can be a rounded fillet or other shape. The most important aspect of the invention is that the lower half of a sealing groove be able to conform to the curvature of the beadedrim if the area of sealing contact is forced to move toward the top of the beaded rim of the container because the container diameter is approaching the maximum that the closure can tolerate without the downward depending skirt being flexed to such a degree that the closure cannot be retained on the bead rim. Thus, it can be seen that by conforming the shape of the sealing groove to the contour of the container beaded rim an area of contact can be maintained to maintain a moisture retentive seal between the closure and the container even though the closure is considerably stretched and flexed by a container diameter of greater than optimum size.
Referring now to FIG. 4, a conventional snap-on, coverall closure is shown applied to a container with optimum size opening. It will be seen that the contact between the closure 21 and the container beaded rim 19, is, at most, little more than line contact 22. When a conventional closure is applied to a container opening of greater than optimum size the line of contact 22 between the closure 21 and the beaded rim of the container 19 rides up toward the top of the container brim and can establish another line contact 23 between the closure top portion and the top of the container rim, as shown in FIG. 5. These line contacts are insufficient, however, to prevent the loss of moisture content from within the closed container as is accomplished by the seal produced by the closure of this invention shown in FIG. 6. v
The closure of my invention is generally made of a synthetic thermoplastic material. Polyolefins, polystyrene and polyvinyl chloride are particularly preferred for such an application, although the invention is not limited to these materials but may include other thermoplastic materials alone or in a laminated form such as a thermoplastic coated paper.
The closures of this invention can be used with any container having a rounded beaded rim. As stated above, the invention is particularly applicable to closures for containers for EXAMPLE 1 To containers were added 100 grams of water. These containers were fitted with lids of the prior art design and weighed after closure. Ten more containers were similarly treated, but were fitted with closures of the design of this invention. After 6 days of shelf storage all the closed containers were weighed again.
Type Closure Range Average Prior Ar! 0.63 to 1.24 1.01 This lnvention 0.6l to 095 0.73
Reasonable variation and modification are possible within the scope of the foregoing disclosure and the drawings, the essence of which is that there has been provided a closure of flexible material containing a sealing groove in the skin conformed to the contour of the beaded rim of the container to which it is applied to provide a reliable moisture retentive seal with the closed container.
1. A flexible closure adapted to be fitted on a container having a beaded rim comprising:
a. a central discoidal portion,
b. a conical frustum portion of increasing diameter extending upward and radially outward from the periphery of said discoidal portion,
c. a radially outward extending annular portion attached to the top of said conical frustum portion and of increased thickness toward the radially outer periphery, forming in conjunction with said conical frustum portion an upwardly extending groove on the inside of the closure, and
d. a downwardly depending skirt of decreasing thickness attached to said thickened annular portion, said skirt containing on its inside a groove which conforms substantially to the opposed surface of the beaded container rim to which it is to be fitted.
2. The closure of claim 1 wherein said downwardly depending skirt contains on its inside a groove the lower half of which conforms substantially to the opposed surface of the beaded container rim to which it is to be fitted.
3. The closure of claim 1 wherein said downwardly depending skirt is offset from said annular portion to produce a groove on the outer perimeter of the top of the closure.
4. The closure of claim 1 wherein said flexible material is a synthetic organic thermoplastic.
5. The closure of claim 1 in combination with a container provided with a beaded rim at its opening wherein the beaded rim of the container and the groove contained in the skirt of the closure are adapted to form a moisturetight seal.