FIELD OF THE INVENTION
The present invention relates generally to removable covers for containers, and more particularly, to removable and reusable covers for use with microwavable containers.
BACKGROUND OF THE INVENTION
It is known to provide a removable cover for a container, such as a container of food or drink. Many such containers can be placed in a microwave oven to heat their contents. The cover or closure functions to prevent the contents of the container from spilling when the container is moved, or splattering when being heated in the microwave. However, many prior art container covers have suffered from deficiencies. Depending on their construction, they may be difficult to put on or to remove, or may be too easily detached, thereby resulting in inadvertent removal of the cover. Many prior art container covers suffer from distortion when heated in the microwave. As a result, the attachment of the cover to the container is impaired or the quality of the seal between the cover and the container is reduced.
A need, therefore, exists for a cover which is easier to put onto and take off of a container, inhibits inadvertent removal, and that seals more dependably.
SUMMARY OF THE INVENTION
The invention is directed to a container cover for use with a container having a neck with an outer bead ring or lip. In exemplary embodiments, the container cover comprises a lid with a skirt extending downward from the circumference of the lid and a concentric plug seal extending downward from the bottom of the lid disposed inside the skirt. The skirt includes a plurality of flexible locks each having at least one inwardly projecting wedge, which hold the cover in place on the container by engaging the container neck bead ring. An edge of each lock is defined by a slot extending through the skirt that allows the lock to flex to disengage the bead ring.
When the cover is installed on the container, the wedges on the inside of the locks engage the outside of the container neck, and the plug seal preferably sealingly engages the inside of the container neck. In an embodiment, the lid is circular and fits on a container neck with a circular cross section. In an embodiment, the skirt has two slotted flexible locks disposed on opposite sides of the cover.
Other objects, aspects and advantages of the present invention will become apparent to those skilled in the art upon reading the following detailed description, when considered in conjunction with the appended claims and the accompanying drawings briefly described below.
BRIEF DESCRIPTION OF THE DRAWINGS
For the purpose of illustrating the invention, there is shown in the drawings embodiments that are presently preferred; it being understood, however, that this invention is not limited to the precise arrangements and constructions particularly shown. In the drawings:
FIG. 1 is an isometric view of an embodiment of a container cover according to the present invention.
FIG. 2 is an isometric view of the bottom side of the cover of FIG. 1.
FIG. 2A is an enlarged view of a portion of the cover shown in FIG. 2.
FIG. 3 is a plan view of the top of the container cover of FIG. 1.
FIG. 3A is an enlarged partial section view of the cover shown in FIG. 3 taken along lines 3A-3A.
FIG. 3B is a cross-sectional view of the cover shown in FIG. 3 taken along lines 3B-3B.
FIG. 3C is a cross-sectional view of the cover shown in FIG. 3 taken along lines 3C-3C.
FIG. 4 is an isometric view of the container cover of FIG. 3 illustrating the top of the cover.
FIG. 4A is an enlarged view of a portion of the cover of FIG. 4.
FIG. 4B is an enlarged view of a portion of the cover of FIG. 4A.
FIG. 5 is a cross-sectional view of a cover according to one embodiment of the invention attached to a container (shown in phantom), and with a second cover stacked on top.
FIG. 5A is an enlarged view of the interface between the two stacked covers of FIG. 5.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings which illustrate several preferred embodiments of the invention, a container cover is shown for use on a microwavable container. The container cover preferably includes a plurality of integral locks. The cover is preferably microwavable and easily removed and reapplied to the container by the user. It is contemplated that the cover can be locked onto the top lip of the container during an assembly process at the factory, keeping the top surface of the container clean during shipping and storage. To remove the cover cap, the user can pull up on the lock. This mechanical action moves the lock away from the container bead ring, making it possible to lift a section of the cover. Simultaneously as the user lifts up on one section of the cover, the cover is moved forward in an arc, causing the other lock or locks to flex, thereby disengaging them from the container rim.
In an exemplary implementation, after the user has removed the cover, the user opens the container, such as by pulling upward on a now exposed metal ring tab of a sealed container top, completely separating the top from the container and discarding it. Next, the user replaces the cover cap and places the container and cover combination into a microwave. Vent holes may be included and serve to vent steam generated in the container by the heating process.
The container may be of any size or shape and may be fabricated from any of a variety of materials. Preferably, the container contains food products which are heated in a microwave oven prior to consumption. Therefore, container is preferably fabricated from a material suitable for use with food products and for heating in a microwave, for example a thermoplastic material such as polypropylene formed by injection molding. As shown in FIG. 3A, the container 500 preferably includes a neck or rim with a protruding lip having an outer bead ring 502, or similar structure proximate to its upper end 504. The outer bead ring 502 may be disposed directly adjacent to the upper end 504 of the container 500 or in close proximity thereto. While the container 500 and the cover 10 are illustrated as each having a substantially circular shape, it will be appreciated by those of ordinary skill in the art that the teachings of the invention are applicable to a variety of other shapes. The following description and embodiments of the invention are not intended to describe all cover/container combinations, but are merely illustrative of how the teachings of the present invention may be employed in the context of a preferred container configuration.
Referring to FIGS. 1 and 2, the container cover 10 includes a lid 20, having a top surface 21, a bottom surface 22, and a circumferential edge 23. When installed on the container, the top of the lid faces away from the container, and the bottom of the lid faces into the container. The cover also includes a skirt 30 extending downward from or near the circumferential edge 23 of the lid 20. The skirt 30 has an inner surface (or wall) 31 and an outer surface (or wall) 32. When installed on the container, the outer wall faces away from the container, and the inner wall faces toward the container and is preferably shaped to fit snugly around the outside of the container neck and/or outer bead ring. The container cover is held onto the container by a plurality of locks or lock panels 40. The lock panels engage the outer bead ring on the neck of the container, as will be described hereinafter.
FIG. 2 is an isometric view of the bottom of the cover of FIG. 1. FIG. 3C is a cross-sectional view of FIG. 3 (a top view of cover 10), seen along lines 3C-3C. Referring to FIGS. 2 and 3C, plug seal 50 is preferably formed concentrically to the skirt 30 and has a smaller diameter than the skirt. The plug seal 50 extends from the bottom of the lid and preferably connects along its entire length to the bottom of the lid. As shown in FIG. 3A, the plug seal 50 has an outer wall shaped to preferably fit snugly and sealingly against the inside of the neck or rim of the container. Thus, the plug seal 50 forms a seal against the inside surface of the container rim to prevent or inhibit the contents of the container from readily passing between the container cover and the container rim. As shown in FIGS. 2, 3A, and 3C, a plurality of stop ribs 60 preferably extend from the inside of the skirt and/or the bottom of the lid. The stop ribs are located so that, when the cover is installed on a container, the stop ribs touch the top of the container neck limiting the downward movement of the cover onto the container.
FIGS. 2A and 3A illustrate the lock panel 40 in more detail. The lock panel 40 is preferably formed as part of the skirt 30. The lock panel includes at least one and more preferably two or more locking wedges 70 that extend inward from an inside surface of the lock panel 40. While only one wedge 70 is visible in FIG. 3A, FIG. 2A illustrates that it is preferable that each lock panel 40 includes a plurality of wedges 70. In a locked position, each locking wedge engages the lower edge of outer bead ring of the container. In an unlocked position, each wedge 70 is released from the outer bead ring 502.
FIG. 2A is an enlarged view of a portion of FIG. 2 showing the lock panel 40. Also shown are slots 80, which are formed in the skirt 30 on either side of the lock panel 40, thus defining the circumferential location of, which define the ends of lock 40. The slots extend at least partially up the skirt 30. Preferably the slots extend at least halfway up the skirt between the bottom and top of the skirt. More preferably, the slots 80 extend more than 50% of the skirt height. The slots permit the flexing of the lock panels 40, thereby permitting the locking wedges to disengage from the container bead 502.
The lock panel 40 includes the locking wedge 70, which extends from the inner wall of the skirt 30. The wedge 70 can be seen in FIGS. 2A and 3A in the shape of a triangle, with a substantially flat surface portion facing towards the top of the cover (i.e., upward). While the preferred embodiment includes a locking wedge that is triangular or wedge-shaped in cross-section, it is contemplated that other cross-sectional shapes, such as quadrangles or circular shapes, may be used.
Providing the slots 80 through the skirt 30 adds flexibility to the skirt and the lock panels. Defining a lock panel by the slots allows the panel to flex outward away from the container rim as the wedges pass over the container bead ring when the cover is applied or removed. When removing the cover, the slots in the skirt enable the lid to flex when the lock is lifted, promoting easy removal of the cover.
As shown in FIG. 3A, the level of the top of a locking wedge (i.e., the vertical location of the tops of the wedges on the skirt) is indicated by dashed line X1. The bottom of a stop rib 60 is also visible. The stop ribs 60 preferably extend from the skirt and/or the lid, and do not interfere with the plug seal 50 when the cover 10 is installed on a container. The distance d between the bottom of the stop rib 60 and the top of the locking wedge 70 is preferably sized so that when the cover is installed on a container having a bead ring 502 on its neck, the bottom of the stop rib 60 touches the top of the neck or the bead ring 502, and each locking wedge 70 engages the bottom of the container bead ring 502, thereby locking the container cover in place.
Prior to microwaving, the user removes the container lid by placing his finger tips under one of the lock panels and lifts upwards. The lifting action disengages the inside locking wedges that are molded on the inside surface of the lock. The slots through the skirt assist in removal of the cover by allowing the entire lock to flex while being pulled out and away from the container rim. When one lock is pulled upward, the other lock or locks begin to flex, causing the locking wedges on the other lock or locks to disengage from the container rim. Above each wedge is preferably a bypass hole 130 that runs through the top and bottom surfaces of the lid. In one preferred embodiment, the bypass hole 130 is formed during the molding process by dies the pierce downward through the lid. In one preferred embodiment, the die forces a portion of the lid material downward while in its moldable state to form the locking wedge. The illustrated embodiment in FIG. 2A shows a portion of the skirt above the locking wedge as being “shaved”, which is the result of the die forming the locking wedge. Although the illustrated embodiment includes holes 130, it should be readily apparent that the openings are not necessary in the cover. Preferably, a flexing slot 140 (shown in FIG. 3) is centered between the bypass holes 130. As shown in FIGS. 1, 3, and 4A, this flexing slot follows the arc of the lid's circumferential edge and allows the lock panel to flex more easily. The increased flexibility of the lock panel due to the flexing slot enables the locking wedges to be placed father apart, providing a wider and more consistent locking pressure area.
As previously described, the container cover is preferably made from one piece injection-molded polypropylene. Polypropylene has a tendency to grow slightly when heated in a microwave oven; such growth creates dimensional changes and deviations. Because the plug seal is in closest proximity to the heating container contents, it tends to experience more thermal growth than the rest of the cover components. The plug seal expansion improves the seal between it and the container rim, thus serving to reduce the possibility of leakage when the contents are extremely hot. Because the locking wedges are also in direct contact with the container, spacing the wedges farther apart creates less vertical distortion of the cover components during heating.
FIGS. 3B and 3C are cross-sectional views of the cover 10. In these figures, it can be seen that lid 20 includes sloping transitional surface 100, which circumscribes a central upper surface 110. A lower annular surface 120 circumscribes the transitional surface 100. Vent holes 90 are preferably formed in the container cover 10 to allow air and steam to escape from the container when the container's contents are heated. It should be apparent to one of ordinary skill in the art that while the embodiment features a preferable number and arrangement of vent holes, any number or arrangement of holes may serve substantially the same purpose.
FIG. 3 is a view of cover 10, showing the top surface 21 of the lid 20. Visible in FIG. 3 are the vent holes 90, arranged on the sloping transitional surface 100. The lid 20 preferably has multiple open vent holes to automatically vent excess steam and heat that could build up during the microwaving process. If the steam was not vented, the steam would build up within that container and could potentially cause an injury to the user when removing the lid.
As shown in FIGS. 3, 3C, and 4, one or more vent holes 90 can be formed in the cover. In the illustrated embodiment, the vent holes 90 are formed on the sloping transition section 100 between the lower annular surface 120 and the upper surface 110. This configuration is designed to create a chimney effect whereupon the heat generated during cooking is channeled toward the center of the cover and escapes through the vents. This keeps the locks and plug seal cooler, and results in less potential for harm to the user while maintaining a better seal. However, while this embodiment is preferred, other numbers or arrangements of vent holes may serve the same purpose.
Referring now to FIGS. 4, 4A, and 4B, the outside surface of the lock panel 40 preferably has a textured area 160 substantially adjacent to the bottom edge of the panel. The textured area 160 includes a plurality of ridges 161, as can be seen in FIG. 4B. The textured area helps keep the fingers of a user from slipping, such as when removing the cover from the container. As shown in the figures, the textured area may be formed in the shape of an arrow to assist the user in the removal of the cover. FIG. 4A is an enlarged view of the cover in FIG. 4, showing the flexible lock panel 40 defined by slots 80. Also shown is a contoured edge 170 that is formed along the bottom edge of the lock panel 40. The contoured edge 170 includes a plurality of recesses or scallops designed to received the figures of the user. The finger recesses permit easy grasping by the user, thereby assisting in the flexing of the lock panel. While the contour is shown as an arrow in the figures, that is only an optional feature.
As shown in FIGS. 5 and 5A, the lids are designed to be stackable, which makes shipping more convenient. The cover preferably includes a raised top ring 150 (shown more clearly in FIGS. 3, 4, and 4A), which is concentric with the circumferential edge of lid 20. The raised top ring 150 may be interrupted by pass holes 130 and flexing holes 140. The top ring 150 has a diameter smaller than circumferential edge 23 of the cover, thus resulting in a space between edge 23 and ring 150. As shown in FIG. 5A, this space is preferably at least as wide as the thickness of skirt 30, and provides a resting place for the edge of skirt 30 of a second lid when multiple lids are stacked.
In a preferred container/cover configuration, the container has a circular neck, and the cover has two lock panels, one on each side of the cover. There are preferably two lock wedges formed on the inner wall of each lock panel. The stop ribs preferably do not touch the plug seal or cause seal distortions. This leaves the plug seal completely free from all connecting obstructions that create unwanted shrinkage, which can lead to leakage problems. Because the plug seal is uninterrupted, it is completely round and preferably provides a 360 degree seal against the inside of the neck of the container. Locating the locking wedges on the skirt allows for simple assembly by placing the cover over the container and pressing the cover directly down onto the container. When the lock panels engage, they preferably make a distinct snap sound as the locking wedges slide over the container bead. The locking action can also be felt by the user through the finger tips as the locking wedges lock over the container bead.
The lock panels are flexible so that the locking wedges will disengage from and slip over the container bead as the cover is removed. The two actions of pulling on a lock panel and lifting the cover need to be done simultaneously or sequentially to remove the cover. As the cover is lifted (or flexed), the other lock panel(s) flex, so that the locking wedges on those lock panels also disengage from the bead, and the cover can be peeled off of the container.
As can be seen in the figures, the skirt and lock panels are designed to permit flexure. Specifically, as discussed above, the lock panels are defined by a slot extending through the skirt. The slots are preferably about 0.06 inch wide and extend about 0.075 inch over the top of the lock wedge, although other slot sizes and placements can also be used.
It will be apparent to those skilled in the art that various modifications and variations can be made in the configuration of the present invention without departing from the spirit or scope of the invention. It is intended that the present invention cover such modifications and variations provided they come within the scope of the appended claims or their equivalents.
Patent Application
20080169287
