BACKGROUND ART AND OBJECTS OF THE INVENTION Food storage containers are generally made of a plastic material such as polypropylene or polyethylene polymers or copolymers. Such containers are normally fairly rigid, but may be subject to some amount of flexure especially where the lid or cover is arranged to be peeled off of the container mouth. Most such container/lid configurations provide a sealing bead or rim along the upper wall of the container with a mating channel on the lid which engages the bead as well as the adjacent inner and outer surfaces of the container wall. Such sealing arrangements generally require considerable effort to force the lid onto the sealing bead during the closing procedure and perhaps greater effort to peal the lid away from the container during the opening process. While some lids are provided with one or more outwardly extending tabs to accommodate a user's fingers, the opening procedure may be quite difficult for a person suffering from arthritis or tendinitis. In addition, the lids of such salable containers often become distorted through heating, dishwashing or refrigeration procedures making lid replacement difficult or impossible. In addition containers designed for microwave use are generally provided with a separate vent located in the lid for preventing pressure build up.

In some designs a separate sealing member such as an 0-ring or annular gasket is disposed between the container rim and the lid channel to provide a more secure seal. Such designs may rely on frictional forces to maintain the lid in place on the container or may rely on latching arms carried by the lids which engage retention lips on the container. In either case the separate sealing member, i. e., 0-ring or gasket involves not only added manufacturing costs, but is subject to being misplaced or lost during use of the container.

There is a need for a more user friendly food storage container/cover which overcomes the above shortcomings.

SUMMARY OF THE INVENTION A container in accordance with the present invention includes a bottom wall and an upstanding peripheral wall terminating in an upper edge surrounding an open top or mouth.

At least an upper portion of the wall is inclined outwardly at a slight angle to the vertical, e. g., 2°-5°, when the bottom wall is positioned in a horizontal plane. While the container is preferably rectangularly-shaped it may also be circular or oval in shape.

A replaceable cover is provided which includes a top, preferably dish-shaped, with a planar top wall terminating in a downwardly extending outer rim flange or skirt. The skirt is arranged to fit over a substantial portion of the upper edge of the container. The cover includes a downwardly extending inner sealing flange which forms an interference fit with the inside surface of the upper portion of the container wall when the cover is pressed downwardly over the mouth or open top of the container.

A pair of latch handles are pivotally mounted on opposite sides of the cover along the outer rim flange thereof with each latch handle being provided with a protruding locking tab arranged to snap under a section of the peripheral upper edge of the container wall when the latch handle is rotated downwardly to lock the cover in a sealing relationship over the container mouth. Also when one of the latch handles is rotated to its unlocked position expanded fluid within the container will cause the lid (or a portion thereof) to rise slightly during microwave cooking to provide the necessary venting action to prevent excess pressure build-up.

The construction and function of the preferred embodiment of the container/cover arrangement of the present invention may best be understood by reference to the following description taken in conjunction with the accompanying drawings in which like components are designated by the same reference numeral in the several figures.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective top view of a container and cover in accordance with the present invention showing the cover in a separated condition with the latch handles unassembled; Fig. 2 is a perspective bottom view of the container/cover of Fig. 1 showing the bottom of the cover and container in some detail; Fig. 3 is a top plan view of the container; Fig. 4 is a cross-sectional view of the container taken along lines 4-4 of Fig. 3 showing the angle that the upper portion of the container side wall makes with the vertical ; Fig. 5 is a bottom plan view of the cover; Fig. 6 is a side elevational view of the cover; Fig. 7 is a cross-sectional view of the cover taken along lines 7-7 of Fig. 5; Fig. 8 is a top plan view of one of the latch handles; Fig. 9 is a bottom plan view of a latch handle; Fig. 10 is a side elevational view of a latch handle; Fig. 11 is a bottom plan view of the container and cover in an assembled and locked position; Fig. 12 is a top perspective view of the container and cover with one of the latch handles rotated to its fully upright position illustrating the simultaneous application of upward pressure to the latch handle and downward pressure to the cover for breaking the seal and releasing the cover from the container; Fig. 13 is a side elevational view of the container and cover in an assembled and locked position; and Fig. 13a is a enlarged sectional view of the right medial end of the assembled container and cover showing (a) the interference fit between the cover sealing flange and the inside surface of the upper portion of the container side wall and (b) the configuration of the end section of the cover overlying the container handle.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to Figs. 1-4, the container 10 of the present invention includes a flat bottom wall 12 which merges at its periphery, via a rounded corner 14, with a peripheral wall, comprising end walls 16 and side walls 18. As discussed previously, while the container shown in the drawings has a rectangular shape, the container of the present invention may have a circular or oval shape with only a peripheral upstanding wall. The end and side walls of the container 10 are merged, via rounded corners 20, as shown. The peripheral wall (16, 18) terminates in an upper edge 22, via an outwardly extending convex shaped segment 24. The edge 22 surrounds and defines an open top or mouth 24 of the container 10 and forms a pair of horizontally protruding handles 26 above the end walls 16 as shown. The top surface of the handles are substantially level with the plane of the edge 22 simplifying the manufacturing process and allowing the cover to overlie the handles as illustrated for example in Fig. 12 to be described. The bottom wall 12 of the container projects downwardly at the corners forming triangular shaped protruding feet 28.

The peripheral wall (16,18) has a slight convex surface, preferably formed along a radius R of about 75 inches, so that an upper section 30 of the peripheral wall (extending below the curved segment 24) is disposed at about an angle 6 of 2° to 5° and preferably about 3° to the vertical with the bottom 12 lying in a horizontal plane as is illustrated in Fig. 4. This slight angle facilitates the entry of a peripheral sealing flange or fin 44 on the cover, as will be explained in more detail, to enter the mouth of the container and form an interference or sealing fit with an inside rectangular sealing surface area within the section 30 when a cover 32 is seated onto the container. See Figs. 11 and 12.

Referring now to Figs. 1,2 and 5-8, a replaceable cover or lid 32 for use with the container 10 is formed with a generally planar depressed wall section 34 which merges with an upwardly inclined peripheral section 36 joined along apex 37 to a downwardly extending outer rim flange or skirt 38. The top of the cover, i. e., wall 34 and section 36 forms a dish-like shape for receiving the bottom of a like container/lid combination in a nesting arrangement. The outer flange or skirt 38 is interrupted by a pair of axel sections 40 which are spaced from the adjacent wall section 34 as is illustrated in Figs. 1 and 5 to receive latching handle 48 to be described. The skirt 38 fits over the upper edge of the container except for the axel portions. The cover 32 includes extended end sections 42 which fit over the top of the container handles 26 in the assembled condition. The end sections 42 define slightly depressed oblong sections 43 which overlie and accentuate the container handles.

See Fig. 13a.

The cover 32 further includes a downwardly extending inner sealing flange or fin 44 positioned inwardly of the outer skirt 30. The fin 44 preferably has a slightly greater periphery than the periphery of at least the lower rectangular portion 30a of section 30 of the peripheral wall of the container so that lower end of the fin 44 is deflected slightly inwardly by the wall portion 30a in the assembled condition. The slight deflection enhances an interference and sealing fit between the fin 44 and the inside surface of the container peripheral wall. See, for example, Fig. 13a. Spaced vertical ribs 46 are formed along the underside of the peripheral section 36 and the inner side of skirt 38 as shown in Fig. 2 to provide structural rigidity and seat on the upper edge 22 of the container.

Referring now particularly to Figs. 8-10, the cover or lid 32 is removably secured (and sealed) to the container 10 by means of a pair of oppositely disposed latching handles 48 which engage the underside 50a of a pair of latch hooks 50 formed on the outside of the peripheral upper edge of the container wall as is illustrated by the dashed lines in Fig. 13. Each latch handle is formed with an upper surface 48a including an outwardly extending finger engaging surface 48b, a back wall 48c and a lower surface. The lower surface is formed with a pair of short protruding spaced inner walls 48d which together with the back wall form two semicircular recesses 48e with downwardly faced openings 48f for receiving an associated axel 40. The lower latch handle surface further forms a downwardly protruding locking tab 48g for engaging the lower edge 50a of an associated locking hook 50 on the container wall. Additionally the lower latch handle surface includes a finger engaging surface 48h.

The latch handles are assembled to the cover or lid 32 by spreading the inner walls 48 slightly away from the back wall 48c (in a snapping action) to allow each axel to enter the respective recess 48e. The back wall 48c of each latch handle limits the rotational movement of the associated latch handle to about 90° by engaging the edge 34a of the wall 34 when the upper surface of the handle is about parallel to the surface 34. It should be noted that the edge 34a may include a small upward curvature formed as part of the arched peripheral section 36.

The container 10 may be made (i. e., injection molded) of a suitable rigid or semi-rigid plastic such as polypropylene, but is preferably made of polycarbonate which is suitable for microwave and conventional dishwasher use. While the bottom of the container may be frosted the sides are preferably transparent or translucent to enable the food or material stored in the container to be readily viewed. It should be noted that to vent excess gas pressure from the container interior (as a result of cooking) it is only necessary to unlatch one of the latch handles.

The cover or lid 32 as well as the latch handles may also be made of a suitable plastic, but are preferably made of polypropylene, having sufficient rigidity so that the inner flange of skirt 44 forms an interference or sealing fit with the inner surface of the container wall in the assembled condition.

The cover also preferably has sufficient beam strength and flexibility so that when an upward force is exerted on the finger engaging lower surface 48h of one or both latch handles (when in their upward most position) and a downward force is exerted on the planar top cover surface adjacent the latch handle the outer rim flange 38 will flex outwardly and upwardly to break the seal and disengage the cover from the container.

This feature adds to the user friendliness of the container/lid arrangement and particularly for persons suffering from arthritis or tendinitis of the hands an wrists.

In use the cover 32 with the latch handles assembled thereon may be placed over the mouth or top 24 of the container 10 and then pressed downwardly until the ribs 46 are seated on the container's upper edge 22. In this position the inner sealing flange 44 forms an interference fit with the inside of the container peripheral wall. The latch handles may then be easily rotated to a closed position by pressing downwardly and inwardly on the finger engaging surfaces 48b until the locking tabs 48g snap under the locking hooks 50.

The locked container and cover, with the contents stored therein, is now ready for storage. To open the cover it is only necessary to rotate one or both of the latch handles to an unlocked position and lift the cover. If desired, one latch handle (or both) may be rotated to its upper most position and pressed upwardly (e. g., by a finger 52) while an area of the planar surface of the cover adjacent the handle is simultaneously pressed downwardly (e. g., by a thumb 54). This simple maneuver causes the surface 34 to assume a slightly concave bow to break the seal and release the cover from the container. See Fig. 12.

The storage container/cover can be made in a variety of sizes, i. e., lengths, widths and depths (e. g., 12"x 7 "x 2" etc.), with or without a designed stacking system. The container with the cover removed may be used as a serving dish.

There has thus been described an improved, simple and inexpensive container/cover combination which provides a reliable sealing system for food stuffs. Various modifications of the combination will occur to persons skilled in the art without involving any departure from the spirit and scope of the invention as defined in the appended claims.