Press type closure with double seal

Abstract

A closure suitable of insertion over the opening of a tubular or similarly constructed member and adapted to hermetically seal that opening. The closure construction includes a fluted center main wall that particularly adapts it for placement upon the tubular member by a light application of finger pressure to the approximate center of the main wall. Likewise, the sealing feature of the closure includes upper and lower sealing beads positioned on the outside surface of the inner seal wall.

Description

This invention relates to containers and container closures which, preferably, are formed from distortable material of construction. More particularly, the invention concerns reusable, plastic container closures for open-mouthed containers and further contemplates a closure similar to that described in U.S. Pat. Nos. 3,679,088 and 3,679,089 which quickly and easily effects and assures a lasting reliable hermetic seal.

Food storage containers, including those formed of plastic materials, have been available for many years and have generally employed a bowl, cylinder or similarly shaped tubular vessel and a separate closure or lid made of a relatively flexible material. The closures for such vessels have normally been of several types. One of these types includes an inverted peripheral groove that is placed upon the top edge or rim of a container wall and is pressed onto or expanded over that edge to form a hermetic seal between two parts. The application of such a closure usually requires that the user apply pressure all around the periphery of the closure to effectively seat same upon the container. Another typical closure is the two position type which may be flexed to either of two stable positions. In one of these positions, the closure may be easily placed over the rim or within the open-mouth of a container, and then may be flexed to the second position. This flexing action either expands or contracts the peripheral portions of the closure and forces it into tight locking contact with the rim or inside container wall. Others, of course, include the cork-like and toggle action closures which loosely fit into the open mouth of a container and which are thereafter expanded into contact with the container inside wall surfaces.

As might be expected, all of these closures as well as those described and claimed in the above-mentioned patents, have been quite satisfactory in operation and construction. It should be noted, however, that each is not wholly satisfactory. Since the various deficiencies of most are discussed in U.S. Pat. Nos. 3,679,088 and 3,679,089, further review thereof here is unnecessary. Furthermore, it has also been found that larger sized closures of U.S. Pat. Nos. 3,679,088 and 3,679,089, when mounted on their containers, left microscopic openings between the container wall and the closure inner sealing wall. Accordingly, such larger seals permitted the passage of small quantities of contained fluid and did not effect a lasting hermetic seal.

As with the earlier closure, this invention provides a sealing closure that is, in all respects, a compromise between the known prior art closures and incorporates the best features of those mentioned above. Likewise, the construction enables the user to apply a closure to a container simply by applying pressure at the approximate center of the closure top wall.

This new closure, however, further includes several distinctive constructional features which enhance its applicability for use in larger sizes. Basically, the improvement relates to the inclusion of a secondary sealing bead to the outside surface of the inner sealing wall. This additional bead compliments the sealing effect of the primary bead and completely effects the desired hermetic seal.

The various objectives and advantages will become more apparent upon further reference to the specification, drawing and claims which describe the invention in more detail and wherein:

FIG. 1 is a top view of a closure construction incorporating the concepts of this invention;

FIG. 2 is a bottom view of the closure shown in FIG. 1;

FIG. 3 is a cross-sectional view of the closure taken along line 3--3 in FIG. 1;

FIG. 4 is an enlarged partial cross-section of the center main wall area of the closure taken along line 4--4 in FIG. 1.

FIG. 5 is a partial enlarged cross-section of the closure area bounded by line 5--5 in FIG. 3;

FIG. 6 is a partial enlarged cross-section of the closure area bounded by line 6--6 in FIG. 3;

FIG. 7 is a partial enlarged cross-section of the closure taken along line 7--7 of FIG. 5; and

FIG. 8 is a partial enlarged cross-section of the closure area bounded by line 8--8 in FIG. 2.

Referring to FIGS. 1 and 2, one will appreciate the overall general construction of the closure member 10 which includes essentially three functional parts, a peripheral inverted U-shaped groove or lip 12, a center main wall 14, including the flutes 16, and a centrally positioned substantially planar or button area 18 in that center main wall. These flutes or corrugations 16 emanate from the substantially planar area 18 and terminate at, in or as the inner seal wall 20. The seal wall 20 forms a part of the lip 12 and it is portions of this lip that effect the seal between the closure 10 and its mating container (not shown).

As noted above, the inner seal wall 20 forms a portion of the lip 12 in closure member 10. This lip and the U-shaped groove are completed by an outer wall 22 and an interconnecting substantially horizontally disposed top wall 24. The outer surface 26 of wall 20 is adapted for mating engagement with the inner wall of the open mouth of a suitable container (not shown). This engagement, of course, creates the hermetic seal spoken of and thus produces a highly desirable storage container especially suited for the storage of foodstuffs. Likewise, the outer and top walls 22 and 24, respectively, function to properly position the closure on the container.

The structural aspects of the center main wall 14 are virtually identical to those described in the above noted patents. Accordingly, upon the application of pressure to the planar area 18, the flutes will tend to collapse upon one another thus displacing the inner seal wall 20 inwardly with them. Furthermore, the diameter of at least a portion of the inner seal wall 20 is larger than that of its mating container so that the subsequent sealing relationship can be formed therebetween. Seemingly, the entire center main wall 14 would continue to collapse with an umbrella-like result if it were not for the reinforcing and stiffening effect of the side wall 20 and lip 12. Despite this restraining effect, the corrugated wall 14 continues to function as described and, in fact, the resilient return of the closure to its approximate as molded size and shape after each distortion is presumably aided by the noted side wall 20.

As is readily apparent in FIGS. 3, 5 and 6, the inner seal wall 20 also includes an outwardly protruding bead 28 which extends around the periphery of outer surface 26 of side wall 20. As indicated above, when the closure is manufactured in large sizes (10 inch diameters and above), this bead 28 has a tendency to distort slightly. Such distortion is theorized to be caused due to variances in the shrinkage of the center main wall 14. And, of course, the end result of that distortion is the creation of microscopic openings between the container wall and sealing bead 28.

To alleviate this problem, the present invention contemplates the further inclusion of a secondary sealing bead 30 above the first or primary bead 28. This secondary bead is also integral with inner seal wall 20 of lip 12, and preferably is positioned on that wall in an area where the effect of shrinkage distortion is minimized. Likewise, in another embodiment of the invention, the primary bead 28 is also positioned slightly above the uppermost point of intersection of the center main wall 14 and inner seal wall 20. Accordingly, in such embodiment both beads 28, 30 would be positioned so as to be affected by the effect of shrinkage on wall 20.

Turning to FIGS. 5 and 6, one will gain a better appreciation of the relationship between the beads 28 and 30. Accordingly, these two beads form separate spaced apart, continuous annular rings around the exterior surface of wall 20. These rings also, as is readily apparent, lie within the bounds of the U-shaped groove walls 22 and 24. Further, it is thus apparent that bead 28 is constructed to provide a maximum sealing surface, while the bead 30 is designed as a more flexible supplementary element. Note, in particular, that this secondary bead 30 is of finger-like construction and projects downwardly into the U-shaped groove opening at approximately a 45.degree. angle. Thus, a bending moment is created in the finger-like bead 30 upon the application of closure 10 to a container and such forces that bead into sealing engagement with the container inner wall. In addition, the lower primary sealing bead 28 takes considerably hydrostatic pressure off the secondary bead 30 so that even if microscopic openings are present along both sealing areas, it (the pressure) is sufficient to force liquids therethrough.

Another aspect of construction which may be employed with closures of this type is clearly exhibited in FIGS. 2, 5, 7 and 8. There, the ribs 32 are exposed and may be seen to extend from wall 20 along the underside of wall 24 and then downwardly along the inside of outer wall 22. These ribs are spaced at selected intervals around the lip so that air can be easily expelled from the container (not shown) as the closure 10 is applied. Note, in particular, that by extending the ribs 32 down the outer wall 22, sealing between that wall and the container 20 is prevented during the application of the closure. This enables a maximum of air to be displaced from the container and thus creates a more desirable inside condition in the container subsequent to its being sealed by closure wall 22 and beads 28 and 30.

In the new closures of this invention, there is a tendency to experience a lateral displacement within the fluted area 18 as pressure is applied to the planar area 16 in the approximate center of the main wall 14. The fluted construction accentuates this displacement as the center main wall 14 folds upon itself in an accordion-like fashion. This, then, similarly tends to enable the side wall 20 to draw inwardly, thereby facilitating entry of the central surface wall are 14 into the open-mouth end of a container or tubular member. After insertion and upon release of the applied pressure, the resilient closure material, due to its elasticity, attempts to assume its relaxed or as molded orientation and thus expands the side wall 20 against the inner portion of the container wall to hermetically seal the container. To remove the closure, it is only necessary to apply an upward pressure against the U-shaped seal lip 12 thus prying the closure off from projecting edge of the container.

From the foregoing description, it should be apparent that the invention encompasses an advantageous advance in the art. Further, it should be clear that the invention may be embodied in other specific forms without departing from the spirit of the essential characteristics thereof. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims

We claim:

1. A locally distortable plastic closure contractably and distensibly constructed and having an elasticity such that it is adapted to hermetically seal an open-mouthed member and comprising:

a. a center main wall including a corrugated area emanating from a center portion thereof toward a peripherally extending wall, said center main wall being adapted for the application of pressure to the approximate center thereof in such manner that said corrugated area tends to collapse upon itself and substantially uniformly displace said peripherally extending wall until said closure is easily positionable on an open-mouthed member; and,

b. first and second integral extended sealing beads positioned around said peripherally extending wall, said sealing beads being displaceable in like manner with said peripherally extending wall such that at least a portion of said sealing means is closely engageable with and sealable against the walls of an open-mouthed member due to the resiliency and elasticity of said closure upon the discontinuance of applied pressure to said center main wall and wherein said secondary annular sealing bead is angularly disposed with respect to the horizontal, is of a more narrow cross-sectional configuration than the first sealing bead and is positioned above the first such bead.