US 3380621 A
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Description (OCR text may contain errors)
April 30, 1968 c. B RG JR" ET AL 3,380,621
HERMETICALLY SEALED CONTAINER Filed Feb. 9, 1967 A R THUR C. R/S'SBERGER, JR L A WRENCE A. ULMSCHNE/DER INVENTORS United States Patent 3,380,621 HERMETICALLY SEALED CONTAINER Arthur C. Rissberger, In. Webster, and Lawrence A. Ulrn- Schneider, Rochester, N.Y., assignors to Eastman Kodak Company, Rochester, N .Y., a corporation of New Jersey Filed Feb. 9, 1967, Ser. No. 614,929 7 Claims. (Cl. 220-44) ABSTRACT OF THE DISCLOSURE A container comprising a bottom and a reclosable cover both formed by a molding technique has a gasket arrangement which accommodates for any mold parting line formed in the container parts as the result of their being molded in order to provide a hermetic seal between the cover and the bottom. For venting the interior of the closed container when the pressure within the container exceeds that acting on the outside thereof, the bottom is provided with a normally closed pressure relief vent the valve of which may be formed by a component of said gasket arrangement but allows the container to be vented without breaking the seal between the cover and the bottom.
The present invention relates to containers, and particularly to containers which are capable of being hermetically sealed.
A conventionally used method of vapor barrier packaging of many products, including photographic products, has been the common heat-seal aluminum foil wrap which is susceptible to being perforated by sharp corners on the product packed or by heavy external impacts. To provide a suitable moisture vapor barrier package when the product is too large to seal in foil, it has been com mon practice to use slip cover metal cans which are sealed by covering the joint between the cover and the bottom with overlapping convolutions of pressure-sensitive tape. Such cans are not strong enough to resist side blows and have, therefore, generally been strengthened by the use of a tubular liner which, for practical economic reasons, is made of paper board. Movement of the contents of the container against this liner creates fiber dirt which is objectionable. While it is well known to package material in hermetically sealed containers, with or without vacuum packing, the seals of such packages are generally destroyed when they are once opened. Also, while the vacuum packing of containers is widely practiced, the containers ordinarily used are not generally ones which are reclosable, and they have generally had to be individually evacuated at the time the container is filled and before, or at the same time, the container is hermetically sealed.
The primary object of the present invention is to provide a hermetically sealed container which overcomes the above-noted disadvantages of such prior art containers.
More specifically, the objects of the present invention include providing a container having a readily removable snap-on cover which provides a reclosable hermetic seal after each opening by merely pressing the cover in place but which cover is not subject to being accidentally dislodged by impacts it might encounter during handling of the container; providing a container which has at least a single one-way venting valve so as to eliminate the possibility of the cover being accidentally blown off in the event the pressure within the container becomes greater than that acting on the outside of the container and/or to allow a group of such containers to be vacuum packed after the cover is in place by merely placing them in an evacuation chamber; providing a container which is so constructed that the bottom part and the cover can be molded from a plastic material and a single gasket located in a peripheral groove extending about the container bottom will accommodate for any mold parting lines left in the parts and provide a reclosable hermetic seal for the cover and at the same time provide the one-way valve for venting the interior of the container to the outside.
The novel features that we consider charactertistic of our invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and its methods of operation, together with additional objects and advantages thereof, will best be understood from the following description when read in connection with the accompanying drawings, in which:
FIG. 1 is a partial side elevational view, partly in section, of a circular container constructed in accordance with one embodiment of the present invention, and
FIG. 2 is an enlarged sectional detail of a container constructed in accordance with another embodiment of the present invention.
Referring now to FIG. 1, a circular container 10 is shown as comprising open-ended bottom 11 and a flexible snap-on cover 12 which are both preferably molded from a suitable moisture vapor barrier plastic material. Since the cover is one of the reclosable type, it is preferable that it be molded from a thermoplastic material, e.g., any of the olefin family of plastics; polypropylene, high density polyethylene, Saran, etc., because the cover must have a certain flexibility. While for the purpose of withstanding impacts during handling without breaking, it is desirable that the container bottom also be molded from a thermoplastic material, it is possible that it be molded from a suitable thermosetting plastic material, e.g., the urea and phenol formaldehydes, etc. Molded into the outside surface of the bottom 11 adjacent the open end thereof is a recessed channel or groove 13 which completely encircles the bottom 11. The cover 12 has a downwardly extending, flexible skirt 14 the lower end of which has a retaining and sealing rim 15 extending radially inward therefrom. When the cover is pressed down onto the bottom 11 this retaining rim 15 snaps over the upper shoulder 16 formed by the upper edge of the groove 13 to retain the cover in place on the bottom. The lower end of the skirt 14 of the cover as molded has a diameter such that the retainer rim 15 will snap into the groove 13 when the cover is pressed down into place on the bottom. To expand this retaining rim portion of the skirt 14 as the cover is pressed down into place, the exterior of the bottom 11 above the groove 13 is tapered outwardly as shown at 17.
In order to produce the upper shoulder 15 and the groove 13 when the bottom 11 is molded requires a mold with sliding plates which result in a parting line marked 20 which extends into the bottom of the groove 13 and up the tapered portion 17 of the bottom 11. This parting line 20 can either be caused by the mold plates not being accurately aligned and/or by a flashing of the plastic at the parting line of the mold plates. The retaining and sealing rim 15 of the cover by itself would bridge this parting line, and create a passage through which air could move so that there would be no hermetic seal.
To accomplish the desired hermetic seal between the cover 12 and the bottom 11 it has been found advisable to use a soft, resilient snap-on, or molded in-place, gasket 22 which is thicker than any parting line 20 which might result from the mismatch of the sliding plates of the mold or from mold flash. This gasket 22 is retained by the groove 13 and encapsulates and seals off the parting line deficiencies. As the cover 12 is pressed into place and the retaining rim 15 snaps over the upper shoulder 16, the retaining rim 15 flexes inwardly and process into the gasket 22 to form a hermetic seal with the bottom 11.
3 The gasket 22 may be a band of natural rubber which is expanded and snapped into the recess 13, or if it is molded in place it may be formed of any other suitable material, e.g., silicone rubber, latex rubber, polyurethane, etc.
The cover 12 may be readily removed by applying an outward and upward force to the lower end of the skirt 14. However, by reason of the flexibility of the skirt 14 and the resilience of the gasket 22, the cover can be replaced and will reform a hermetic seal. In order to prevent the cover from being accidentally dislodged during handling of the container, the container bottom 11 is provided with a lower shoulder 25 which extends radially outward from the periphery of the container by an amount at least equal to that by which the skirt 14 of the cover 12 protrudes. This lower shoulder will act as a guard for absorbing blows which might other wise accidentally dislodge the cover.
In order to provide all of the above sealing and re sealing advantages to a container having one or more straight sides, e.g., a rectangular container, which, because of their length, may not be rigid enough to oppose the flexing force of the skirt 14 on the cover 12 so that a hermetic seal can be eifected between the retaining and sealing rim 15 and the gasket 22, the cover 12 may be modified as shown in the embodiment of FIG. 2. In this embodiment the cover is provided with a back-up rail 26 which extends downwardly from the underside of the cover in concentric spaced relation to the skirt 14. When the cover 12 is pressed onto the bottom 11 this back-up rail 26 engages the inside of the top or open end of the bottom and gives it the necessary rigidity to effect a hermetic seal between the cover and bottom. It necessary the backup rail 26 may be supported with one or more buttresses 27, as indicated in FIG. 2. While circular containers do not normally require the use of this back-up rail and buttress reinforcement, the use 01 such a reinforcing means on the cover is not limited to containers having rather long straight walls.
It will be apparent that with a container having a snap-on cover of the type disclosed under certain conditions the pressure within the container might become such as to blow the cover off the bottom. One example of a situation where this might occur is where a container packed under atmospheric conditions is carried up to a high elevation in an airplane which is not pressurized. Another example is where the contents of the container might give off a gas, e.g., by fermentation or the like, so that the gaseous pressure within the container finally builds up to exceed the atmospheric pressure acting down on the outside of the cover.
To overcome this potential problem the container is provided with a one-way pressure relief valve which vents the container only from the inside out and normally hermetically seals the vent. To this end, and as shown in the FIG. 2 embodiment, the wall of the container bottom 11 is provided with one or more holes 30, only one being shown in FIG. 2, which open in the bottom of the groove 13 beneath the gasket 22. If the gasket is a rubber band which is normally stretched to tightly embrace the bottom of the groove then it will act as a normally closed valve for the hole to hermetic-ally seal the same. If the pressure within the container builds up to exceed that acting on the outside of the container for any reason, before the cover 12 blows off the gasket 22 will be expanded away from the hole(s) 30 and vent the container from the inside out. Just as soon as the pressure outside of the container exceeds, or is substantially equal to, the pressure within the container then the gasket will reseal the vent hole. It the pressure outside the container exceeds that within the container, then the outside pressure will assist the inherent resiliency of the gasket to reseal the vent hole. If the pressures within and outside of the container are equal, then it is the inherent resiliency of the stretched gasket which supplies the sealing force. It will be appreciated that by proper selection of the gasket material and the amount it is stretched when it is put in place in groove 13 one can adjust the valve to open under a pressure dilterential just short of that which will blow the cover off the container.
Attention is called to the fact that the vent holes 30 enter the groove 13 at a point below that which the reraining and sealing rim 15 on the skirt 14 of the cover 12 engages the gasket 22 to provide a hermetic seal between the cover 12 and the container bottom 11. This means that the gasket 22 can be expanded to vent the container without in any way affecting the hermetic seal between the bottom 11 and the cover 12. This arrangement of parts also makes it possible to vacuum pack the contents of the container 10 after the container is loaded and the cover is hermetically sealed closed. To this end, a multiplicity of filled containers with the covers in place thereon can be placed in a suitable evacuation chamber which will draw air simultaneously from each container through the one-way relief vents, 22 and 30. Just as soon as the containers have been sufficiently evacuated and atmospheric pressure is turned into the chamber the gasket 22 will immediately hermetically rescal the holes 39. It will be appreciated that this method of vaccum packing a container is much more expedient and simpler than the conventional method of individually evacuating each container at the time the same is sealed closed upon being filled.
While we have shown a container and cover combination which is particularly designed to overcome fabrication problems encountered in molding the parts from plastic or other materials by a molding technique, e.g., mold parting line, mold flash, etc., and wherein one gasket serves both as part of the hermetic seal for the cover as well as a valve for the venting hole in the container, the present invention is not limited to these structural details. For example, the gasket seal for the cover and the rubber band or gasket acting as the one-way valve for the vent hole(s) 30 could be independent parts and separated from one another by any amount along the side wall of the container so long as the relief vent for the container is beyond that part of the wall sealed off by the cover. Also the relief vent feature of this container could be advantageously applied to conventional food containers which are to be vacuum packed, rather than being limited to use in containers having removable covers. For example, metal cans which have their covers spun into place after filling could be provided with a one-way relief venting valve which would allow a multiplicity of them to be evacuated simultaneously in an evacuating chamber rather than individually at the time the cover is spun into place which applicants believe to be the conventional procedure. In this connection the valve couid be a rubber band or its equivalent seated between two heads rolled or otherwise formed in the wall of the can and covering one or more venting holes spaced about can circumference. Or, the can could have one or more holes in its walls normally covered by spring loaded clapper type valves adapted to hermetically seal off the holes and adapted to automatically open and vent the container when the sealed container is placed in an evacuating chamber.
While we have shown and described certain specific embodiments of our invention, we are aware that many modifications thereof are possible. Our invention, therefore, is not to be limited to the precise details shown and described, but is intended to cover all modifications coming within the scope of the appended claims.
1. In combination, a container having an open end through which material can be inserted into and removed from said container; a snap-on cover for closing the open end of said container, and including a skirt adapted to overhang and embrace the outside'wall of said container adjacent the open end thereof; the side wall of said container provided with at least one vent hole passing completely therethrough and located at a point below but adjacent that part of the side wall covered by the skirt on said cover; means, including a single component, providing a reclosable hermetic seal between said cover and said container and a one-way valve for hermetically sealing said vent hole against entrance of air into said container which Will automatically open to vent the interior of the container when the gaseous pressure within the container exceeds that outside of the container but is insufficient to blow the cover from the container.
2. The combination is set forth in claim 1, in which the lower end of the skirt of said cover is provided with a sealing and retaining rim extending radially inward from the inside surface thereof; and wherein said single component of said last-mentioned means comprises a soft resilient band embracing the exterior surface of the side wall of said container and being of such dimension as to normally cover said vent hole and be engaged by the sealing and retaining rim on the skirt of said cover when said cover is snapped onto said container, said band having a density such that it is impermeable to the passage of vapor, a softness such that it will be compressed by said sealing and retaining rim on said cover, and a resiliency such that it will expand to uncover said vent hole when the gaseous pressure within said container exceeds the gaseous pressure outside said container by a given amount so as to vent the interior of said container before the cover blows oil.
3. A reclosable hermetically seal container comprising:
(a) an open-ended bottom molded from a moisturebarrier material;
(b) the outer surface of the upper end of the bottom provided with a recessed groove completely encircling said container bottom, the upper edge of said groove extending radially of said container bottom and forming a cover retaining shoulder;
(c) a gasket of soft, resilient material impervious to the passage of vapor located in the bottom of said groove, said gasket being thicker than the depth of any parting line mismatch or mold flash which might exist in the groove as the result of the molding of the container bottom;
(d) a snap-on cover molded from a moisture-barrier flexible plastic material, and including:
(1) a downwardly extending skirt adapted to embrace the outer surface of the upper end of said container bottom, and
(2) a retaining and sealing rim adjacent the bottom of said skirt extending radially inward from the inside of the skirt to snap over said cover retaining shoulder and to press into said gasket when the cover is pushed onto the open end of said container bottom and thereby form a reclostble hermetic seal between the container bottom and said cover which is releasable by applying an upward force on the bottom of the skirt to remove the retaining and sealing rim from engagement with the cover retaining shoulder on said container bottom.
4. A container according to claim 3, including a lower shoulder encircling the exterior of the container bottom at a point adjacent the bottom of said groove and extending radially outward therefrom to overhang the bottom of the skirt on said cover when it is in place and provide a guard for absorbing any blows which might otherwise accidentally dislodge the cover.
5. A container according to claim 3, and including at least one vent hole passing completely through the wall of said container bottom and opening into the bottom of said groove at a point beneath said gasket engaged by said retaining and sealing rim on the skirt of the cover so that said gasket acts as a one-way valve for venting the container when the gaseous pressure Within the container exceeds that outside of the container while the hermetic seal between the cover and container bottom remains intact.
6. A container according to claim 3, in which the wall of the container bottom is so flexible as to require reinforcement to effect a hermetic seal between the open end of the bottom and the cover, and characterized in that said cover includes a back-up rail which extends substantially parallel to said skirt and is spaced inwardly therefrom to telescope into engagement with the inside of the open end of said bottom when the cover is placed on said container bottom.
7. A container according to claim 6, and including a supporting buttress connecting said back-up rail to the underside of said cover to make said back-up rail sulficiently rigid as to eifect a hermetic seal between the cover and container bottom when the cover is snapped onto said bottom.
References Cited UNITED STATES PATENTS 638,022 11/1899 Lemyre 215-56 2,056,171 10/1936 Deschner 215-56 X 2,129,089 9/1938 Hood 220 2,997,397 8/ 1961 Doulgheridis 22044 X 3,223,278 12/1965 Allen 220-60 FOREIGN PATENTS 87,959 9/ 1921 Austria. 850,984 9/ 1952 Germany. 514,918 II/ 1939 Great Britain.
THERON E. CONDON, Primary Examiner. GEORGE E. LOWRANCE, Examiner.