Three-part Press Type Seal

Abstract

A multi-part and distortable seal construction employing a biased center wall and sealing wall arrangement which, upon the application and release of pressure to a center-positioned plunger, distends and contracts the sealing wall portion thereof.

Description

This invention relates to containers and container closures in which the closures are formed from distortable materials of construction. More particularly, the invention concerns distortable, reusable, plastic container closures for open-mouthed containers and further contemplates a closure arrangement that is quickly and easily operable and which assures a reliable hermetic seal.

Plastic food storage containers have been available for many years and have generally employed a bowl, cylinder, pitcher or similarly shaped vessel and a separate closure or lid made of a relatively flexible material. Further, the closures have normally been of several types, one of which 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 the two parts. Another typical closure is the two-position type which may be flexed to either of two fixed positions. In one of these positions, the closure may be easily fitted over the rim or within the open-mouth of a container, and then when flexed to the second position, its peripheral portions are forced into tight locking contact with the rim or inside container wall. Others include the cork-like and toggle-like closures which loosely fit into the open mouth of a container and which are thereafter expanded into contact with the container inside wall surfaces. Then, of course, there have been the relatively inflexible plug type closures that have been provided for these purposes. Normally, these have been employed with vessels that are also relatively inflexible and include a tapered body portion into which the closure could be inserted until it frictionally engaged the tapered body.

As might be expected, all of the mentioned closures have been quite satisfactory in operation and construction. It should be noted, however, that each is not wholly satisfactory from a plurality of diversified points of view. For example, the closure having the inverted peripheral groove has had to be stretched over or pressed onto the container rim normally by finger pressure applied at successively adjacent points along the top groove defining wall. This, of course, may be a time-consuming and laborious procedure, especially if the closure is as tight fitting as is required to obtain a hermetic seal. Further, when the closure must be stretched in this manner, stress concentrations are increased to such a degree that stress cracking may result. Similarly, lids of this type are susceptible to warpage due to the inordinate internal stresses and in this warped condition, placement of the lid on a container is made more difficult and sometimes even impossible.

The two-position closure may also require some dexterity if it is to be accurately locked in position. When using this closure, the peripheral edge of the closure must be maintained in close association with the top edge of the container as the top wall of the closure is flexed to its locking position. As might be expected, this, in some instances, necessitates that the closure be simultaneously held at the edges and flexed at the center.

Similarly, the toggle-action closures may also require dexterity in their proper assemblage with suitable closures. In addition, however, the toggle action lids include hinged areas that necessarily have been weakened and are therefore more susceptible to failure. These also present numerous molding difficulties which tend to limit the materials of construction from which they may be manufactured. And, of course, like the tightly stretched closure mentioned above, extreme stresses are created in the sealed position and this accelerates stress cracking of the closure. Further, if a roll-type toggle is employed, it is not uncommon for the seal between the closure and container to be lost if items are placed on top of the closure so that the weight of such items depresses the dome-like central area thereof. It should also be apparent that such closures also have a tendency to turn inside-out, thus requiring that the user reinvert the closure before any further attempt is made to seal the container.

The expandible cork-like closures are also deficient in several respects, especially where large open-mouthed containers are concerned. For example, the construction of such closures besides employing complicated mechanical manipulative devices also necessarily decrease the usable volume in where they are used because of their bulk. Likewise, the plug type closures lack versatility and, of course, are somewhat unreliable in their sealing action.

This invention provides a sealing closure that is, in all respects, representative of a composite incorporating the good features of those mentioned above, and in addition, is more simple in its mode of operation. The construction more fully described hereinbelow enables the user to apply the closure of this invention to any of several types of containers simply by an application of pressure to the approximate center of the closure main wall. As is readily discernible from the drawings, this closure is of a multi-pieced construction and includes a finger operable plunger that is adapted to transmit pressure to the approximate center of the main wall.

This new closure further includes several distinctive constructional features which enhance its applicability for use in a food storage capavity as well as in other related fields. Among these is a biased, corrugated, fluted or similar center main wall arrangement that effectively and easily enables the contraction and recovery of the center main wall peripheral edge to a relaxed or as-molded posiltion. This edge, of course, includes as an integral part a sealing wall portion which functions to produce a sealed relationship between closure and container, thus preserving and physically retaining the contained materials therein.

The invention also encompasess variable construction parameters affecting the efficient operability of such closures. Therefore, the construction described in detail below has as its principle objectives to minimize both internal stresses within the closure and the force required to properly assemble a closure and container, while at the same time to maximize the sealing pressure between the closure and container and the lateral contraction of the closure sealing wall portion per unit of applied force. In these respects, it is applicant's wish that the disclosures in co-pending U.S. patent applications Ser. Nos. 8,228, now U.S. Pat. No. 3,679,088 and 67,340, now U.S. Pat. No. 3,679,089 filed on Feb. 3, 1970, and Aug. 27, 1970, respectively, be incorporated by reference in this application for Letters Patent.

Further objectives of the invention, of course, are to provide: an improved closure that is easily applicable to a container and yet will effectively hermetically seal that container; a closure construction which may be molded by compression or injection techniques and which will be economical to manufacture and durable in operation.

Other objectives and advantages will becomd 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 an enlarged cross-section of the closure and a partial cross-section of a pitcher, the closure cross-section being taken along line 2--2 in FIG. 3 and showing the closure in sealing relationship with the container;

FIG. 3 is a bottom view of the closure as is depicted in FIG. 1;

FIG. 4 is a partial cross-section of a typical closure of this invention and of another container; and,

FIG. 5 is a partial cross-section of a pitcher adapted to accommodate the closure of this invention.

Referring now to FIGS. 1-4, it can be seen that the closure member 10 of this invention is composed of a plurality of separate parts which function together in the operation of the closure. These include a radially biased, fluted or corrugated center main wall 14 having a centrally positioned substantially planar area 16 in the center surface wall and an upwardly extended side wall 26; a closure top wall 12 having an integral substantially centered bushing-like guide 13; and a plunger 15. Specifically, the biased or corrugated areas are composed of a plurality of upstanding tapered ridges 18, more fully described hereinafter, which emanate from the substantially planar area 16 and terminate at the peripheral edge 24 of the center main wall 14.

The closure center main wall 14 is preferably formed from a distortable thermoplastic, for example, low density polyethylene; however, high density polyethylene, polypropylene, polyolefin blends or similar materials, even light gage metals may be suitably employed using the inventive concept. Likewise, the open-mouthed containers 20 (FIGS. 2 and 4) with which these closures are primarily intended for use, are also generally formed from the same or similar materials. It should be pointed out, however, that such closures may well be adapted for use with containers of a diversified range of materials such as glass, metal, etc.

Upon continued reference to FIGS. 2 and 4, it can be seen that at the peripheral edge 24 of the center main wall, there is an integral upwardly extended side wall 26. The outer portion 28 of wall 26 is adapted for mating engagement with the inner area of the projecting wall 30 which forms the open mouth in container or pitcher 10. 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 and/or liquids.

These closure embodiments include an outwardly protruding bead 32 which extends around the periphery of outer portion 28 of wall 26 which bead presses against the container walls in sealing relationship with them. FIG. 2 further shows a circumferential ledge 34 which is intended to act as a bottom stop member for the closure 10. As is readily apparent, the ledge is produced by downwardly directed inwardly sloping portion 36 of the pitcher wall 21. This terminates after a relatively short inward progression and the normal inner wall contour is resumed. This ledge tends to assist the user in the proper orientation of the closure on the container; however, as is evident from FIG. 4, containers of other configurations may similarly employ this closure member. In fact, this type of closure may be used to "chase" a diminishing amount of foodstuff or liquid down into the container. This operation would minimize the amount of air trapped in contact with the remaining foodstuff in the container and thereby lengthen the time of preservation of the remaining contents.

Again with particular reference to the pitcher 20 in FIGS. 2 and 5, note that a small interrupted bead 23 partially extends around the inside of wall 21, adjacent the upper edge 27 of the pitcher. This bead functions as an upper stop or position indicator so that the user may accurately reposition the closure 10 immediately below this bead. In this elevated position, the closure will not contact the wall 21 in the area of pour spout 25. Therefore, the closure 10 will remain securely engaged with the pitcher, yet pour spout 25 will be open to the container interior enabling the easy discharge of fluids or the like while the closure is so attached. To assist in this discharge, note that a tapered venting slot 17 is provided on the inside surface of wall 30 approximately opposite pour spout 25 so that when the closure is positioned in its elevated position, air may be bled into the pitcher at that point. For complete sealing of the pitcher 20, however, it is only necessary to again reposition the closure adjacent ledge 34 which is below the pour spout 25. Thus, sealing will be effected all around the pitcher 20 between protruding bead 32 and wall 21.

Referring now to FIG. 3, in particular, one will recognize that in operation the locally distortable closure member is contractably and distensibly constructed so that the wall 26 will be displacible with the peripheral edge 24 of biased center main wall 14. In accomplishing this, the resiliency and elastic memory of the particular materials of construction must be considered and, in particular, the center main wall shape should be carefully constructed to take advantage of the physical characteristics of the materials employed. Therefore, the radially extending biased center main wall 14 which extends between the center portion or substantially planar area 16 to a peripheral terminus 24 is of considerable importance to the invention. In essence, the biased center main wall 14 tends to collapse upon itself upon the application of pressure to center portion 16. This collapse substantially uniformly displaces the peripheral terminus 24 inwardly and thus draws the wall 26 inwardly.

The biased, corrugated, fluted or plaited center main wall 14 includes, therefore, a plurality of upwardly and outwardly tapered ridges 18. As can be readily seen in FIGS. 2, 3 and 4, the upper portion 38 of these ridges are angularly directed with respect to planar area 16 and therefore their respective peripheral terminus portions 24 lie plane removed from that of area 16. Similarly, the bottom portions 40 of these plaits lie in a substantially parallel plane approximate to that of area 16 when the closure is in a relaxed or as-molded condition. However, when the closure is in place upon a container, even the bottom portions 40 will be at least slightly angularly directed toward the container center; such being the result of oversizing which assures a proper seal between the components.

The corrugation height at its peripheral terminus 24, i.e., the point of connection to the integral upwardly extended side wall 26, is such that the uppermost flute portion 38 is approximately opposite or above the protruding bead 32. Thus, even through the lateral dimensions of the outer portion 28 at bead 32 are slightly greater than that of the inside diameter of the container, the application of pressure to the centrally positioned substantially planar area 16 will cause sufficient inward lateral displacement of the side wall 26 such that the closure slips easily onto the container.

As is best apparent from FIG. 2, the side wall 26 also includes a plurality of inwardly and upwardly disposed projections 29 which are integrally molded at spaced points around the wall. These projections 29 terminate at points adjacent the upper edge 35 of the wall and below the inwardly directed undercut 37 that is formed at the upper edge. Similarly, the socket 39 framed by wall 41 projects upwardly from the planar area 16 such that it cooperates with the plunger 15 as is described hereinbelow.

The closure top wall 12 includes a conically disposed upper wall 38 in the approximate center of which there is positioned the bushing-like guide 13. This guide extends above the upper wall 38 and is aligned with the socket 39. A peripherally disposed depending skirt 40 is positioned adjacent the outermost periphery of upper wall 38 so as to create a lip 42 around the periphery thereof. This lip then is positioned between the undercut 32 and terminal points of projections 29 and is securely held therebetween by these elements.

The plunger 15 is, of course, received in the bushing-like guide 13 for axial movement therein and is further received by the socket 39. The socket further includes a plurality of inwardly extending ribs 44 which pressingly engage the plunger and secure it in the socket and to the center main wall 14. As is apparent, plunger 15 also includes a ledge area 47 intermediate of its extremities which ledge area is adapted to engage with the undersurface of wall 38 adjacent bushing 13 and to thereby function as a stop to arrest the upward movement of the plunger and center main wall 14. Thus, axially applied pressure is transmitted by the plunger 15 to the planar area 16 of the center main wall 14 and the displacement of peripheral terminus 24 of wall 26 results as discussed above. The upper portion of guide 13 also includes a finger-grippable flange 45 above which the plunger is adapted to protrude. Thus, in operation the guide may be gripped between the finger digits below flange 45 while the plunger is depressed with the thumb, creating the axial pressure spoken of.

As was mentioned, one prime objective of this invention is to optimize forces for applying closures, sealing pressures and stresses but at the same time, to obtain a maximum of sealing pressure using minimum force and creating minimum stresses. Therefore, analysis of the relationships between the applied axial force (push-down pressure), the lateral contraction or displacement of the side wall 26, the stresses within the closure, and the sealing pressure becomes significant and a discussion of thee may be found in U.S. Ser. No. 8,228 and 67,340, filed on Feb. 3, 1970, and Aug. 27, 1970, respectively.

It should be obvious that other similar top wall and plunger constructions may be employed in carrying out the invention. For example, a sleeve and plunger might be suitably inserted and retained within the bushing-like guide in such manner as to permit elimination of the socket 39. Similarly, the plunger might be made integral with the center main wall 14 thereby reducing the number of separate parts included in the construction.

In operation, the closures of this invention tend to experience a lateral displacement within the conical, corrugated or fluted area 18 as pressure is applied to the planar area 16. The conical corrugated construction accentuates this displacement as the flutes fold upon themselves in an accordion-like fashion. This, then, similarly tends to draw the side wall 26 inwardly, thereby facilitating entry of the central surface wall area 14 into the open-mouth end of the container or pitcher 20. After insertion and upon release of the applied pressure, the resilient closure material attempts to assume its relaxed orientation and thus expands the side wall 26 against the inner portion of the container wall to hermetically seal the container. To remove the closure, it is only necessary to similarly depress the plunger 15 to remove the closure from the pitcher or 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 closure member contractably and distensibly constructed and having an elastic memory such that it is adapted to hermetically seal an open-mouthed container and comprising:

a. a center main wall including a biased area radially emanating from a central portion thereof to a peripheral terminus, said center main wall being adapted for the application of pressure to the approximate center thereof in such manner that said biased area tends to collapse upon itself and substantially uniformly displace said peripheral terminus until said closure is easily positionable in an open-mouthed container;

b. integral extended sealing means positioned around said peripheral terminus of the center main wall, said sealing means being displaceable in like manner with said peripheral terminus such that at least a portion of said sealing means is closely engageable with and sealable against the walls of an open-mouthed container due to the resiliency and elastic memory of said closure upon the discontinuance of applied pressure to said center main wall;

c. a closure top wall interconnected with said integral extended sealing means and said center main wall, said closure top wall further including an integral and substantially centered upstanding bushing-like guide terminating at its upper extremity in a finger grippable flange; and,

d. an axially movable plunger positioned in said guide in such manner as to have a portion thereof exposed above said flange so that pressure applied to the plunger is transmitted to the approximate center of said center main wall.

2. A closure member according to claim 1 wherein said plunger is secured to said center wall at the approximate center thereof.

3. In combination a container and a removable closure member according to claim 1 wherein said container includes a projecting wall construction forming the open mouth thereof and including therein a pouring spout and venting slot approximately opposite one another, said projecting wall construction being so that said removable closure is engageable with and sealable thereagainst below said spout and slot and is engageable and sealable with portions of said wall at positions proximate said spout and slot so that with the removable closure in the latter mentioned positions the container contents may be easily poured therefrom.

4. The combination according to claim 3 wherein said projecting wall also includes inwardly protruding means removed from the upper edge of said container such that said portion of the sealing means is positionable therebetween, said protruding means further providing an abutable surface against which said closure is positionable to assure its proper placement within the container.

5. A closure member according to claim 1 wherein the closure top wall and the integral extended sealing means include opposed locking means interconnectably overlapping to secure said top and main walls together.