US 3794090 A
A thin gauge plastic cover having reinforcing ribs in its annular side wall and top, and a recessed knob-like handle at its top is disposed on a plate for serving food, for example, in institutions. The cover has a lower arcuate rim provided with a plurality of spaced inwardly projecting lugs to lock the cover to the periphery of the plate and to space the remainder of the rim of the cover slightly above the periphery of the plate to allow for venting from the interior of the container. The lugs and reinforcing ribs are arranged to prevent covers from sticking to each other when a plurality of covers are nested together.
Claims available in
Description (OCR text may contain errors)
United States Patent Commisso 1 Feb. 26, 1974 COVERED CONTAINER FOR SERVING FOOD  Inventor: Nicholas D. Commisso, Victor, NY.
 Assignee: Mobil Oil Corporation, New York,
22 Filed: July 14,1972
21 Appl. No.: 271,864
 US. Cl. 150/.05, 220/44 R, 220/60 R, 99/172, 220/97 F [51 Int. Cl A45c 100, B65d100  Field of Search 220/44 R, 60 R, 97 F; 150/.05; 99/172  References Cited UNITED STATES PATENTS 3,690,902 3/1970 Dahl ISO/.05 X 3,511,288 5/1970 Swett et al. 150/05 Primary Examiner-George T. Hall Attorney, Agent, or FirmA. L. Gaboriault; J. D.
Tierney [5 7] ABSTRACT A thin gauge plastic cover having reinforcing ribs in its annular side wall and top, and a recessed knob-like handle at its top is disposed on a plate for serving food, for example, in institutions. The cover has a lower arcuate rim provided with a plurality of spaced inwardly projecting lugs to lock the cover to the periphery of the plate and to space the remainder of the rim of the cover slightly above the periphery of the plate to allow for venting from the interior of the container. The lugs and reinforcing ribs are arranged to prevent covers from sticking to each other when a plurality of covers are nested together.
8 Claims, 6 Drawing Figures COVERED CONTAINER FOR SERVING FOOD BACKGROUND OF THE INVENTION The present invention relates generally to covered containers of the type comprising plates or other dishes which have covers placed thereon for the purpose of keeping the food warm and sanitary.
Heretofore, combinations of this nature, which are used extensively in institutions, such as hospitals for serving patients, as well as in hotels and restaurants, have generally been made of metal and were intended to be washed and reused repeatedly.
SUMMARY OF THE INVENTION It is a primary object of the present invention to provide a novel dish and cover assembly for serving food in which the cover and preferably also the dish can be produced so economically while having the requisite strength and pleasing appearance that they may be discarded after a single use.
In keeping with these objectives, the cover of the invention is formed of thin gauge synthetic plastic such as biaxially oriented polystyrene. The cover which is generally dome shaped is made of thin gauge plastic and has an inwardly and upwardly inclined annular side wall with substantially uniformly spaced flutes and strengthening ribs. The strengthening ribs are continued onto the top of the cover and extend radially inwardly terminating adjacent a recessed handle.
An arcuate rim at the lower periphery of the cover is designed to be positioned upon the peripheral edge of a dish, such as a dinner plate. A plurality of inwardly extending lugs disposed around the circumference of the arcuate rim of the cover aresnapped down over the edge of the dish via a camming action to secure the cover to the dish. The remainder of the rim between the spaced lugs is held slightly above the upper surface of the perimeter of the dish to allow for the venting of steam which may emanate from food upon the dish and to prevent formation of a vacuum.
Prior to use, it is customary to store the covers and dishes in separate stacks. During such storage, the lugs in the annular rim also serve as stacking lugs which limit the extent that adjacent covers nest with each other to reduce sticking of the covers to each other when unstacked.
Excessive nesting of the covers is also prevented by varying the size and location of the reinforcing ribs, e.g., making some of the reinforcing ribs on the side of the cover shorter than the others.
The top of the cover has a recessed region which is contoured complementary to the bottom of the dishes with which the cover is employed so that a plurality of covered dishes may be placed one upon another to facilitate transportation and distribution of the filled containers to the points of use.
The cover is preferably made of a clear plastic such as biaxially oriented polystyrene so that the food on the plate is visible through the cover, but an opaque or colored plastic may also be utilized.
The above and other objects, features and advantages of the invention will become more apparent as this description proceeds.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a plan view of a presently preferred embodiment of the invention.
FIG. 2 is a part sectional, part elevational view of a covered container in accordance with the embodiment of FIG. 1.
FIG. 3 is a partial cross sectional view taken along line 33 of FIG. ll.
FIG. 4 is a partial cross sectional view taken along line 4-4 of FIG. ll.
FIG. 5 is a partial elevational view showing one arrangement of a locking lug in relation to the lower ends of the adjacent reinforcing ribs.
FIG. 6 is a view similar to FIG. 5 but of another arrangement of a locking lug and the adjacent reinforcing ribs.
DETAILED DESCRIPTION OF THE INVENTION Reference numeral 10 generally designates a dome shaped plastic cover of a presently preferred embodiment of the invention which fits onto a food serving dish 12 which in the illustrated embodiment is a dinner plate. The cover has an annular side wall which slopes upwardly and inwardly at a small angle such as about 15 from the vertical and includes a plurality of flutes 14 having arcuate upper ends 16 which extend inwardly and merge into upper side wall portions 18. Generally wedge shaped indentations separate the flutes 1141 from each other. and constitute reinforcing ribs 20. The reinforcing ribs also extend up through the upper side wall portions 14 into the top of the cover.
The top of the cover includes an outer elevated annular rim 22, a wider generally flat main top section 24 connected to the rim 22 by a curved section 26, a downwardly inclined portion 28 which extends downwardly at an angle of approximately 30 to the plane of the top section 24, and a centrally disposed knob 30 which is employed as a handle. By virtue of the depression in the top formed by the inclined portion 28, the handle is readily accessible without increasing the height of the cover.
It is presently preferred that the cover 10 be made of a thin gauge synthetic thermoplastic such as biaxially oriented transparent polystyrene in the order of about 12 mils in thickness. Other clear or opaque plastics having the requisite strength and ease of processing may also be employed. This gauge material may be utilized in view of the strength imparted by the provision of the reinforcing ribs 20, and in view of the stepped or irregular contour of the cover, i.e., the stepped relationship between the flutes 14 and the upper side wall portions 18, and between the elements 22, 24, 28 and 30 of the top. By virtue of this construction, there are no bend or hinge lines extending across the cover.
At its lower end, the cover terminates in a downtumed arcuate rim 32 which has an outwardly flaring lower edge 34. Referring to FIGS. 2 and 4, the cover is attached to plate 12 by a plurality of lugs. Each lug comprises an outwardly inclined camming surface 35 and an upper surface 36 which is inclined inwardly at a slight angle from the vertical. When the cover is positioned upon the plate, the lugs function as locking elements which are pressed down over the upper peripheral edge 38 of the plate 12 into a snap-fit engagement. In the illustrated embodiment there are six of these locking lugs approximately equally spaced around the periphery of the cover, but the number of lugs is a matter of choice. There is sufiicient resiliency in the rim 32 that the locking lugs may be deflected slightly outwardly in order to allow them to slip over the rim 38. To facilitate this snap-fit, it is also preferred that the plate rim be capable of a slight downward and inward deflection upon initial contact with the locking lugs so that the lower end of the lug may snap under the bottom edge of the rim 38.
It is contemplated that the dish with which the cover is associated may also be disposable and made of an economical material such as paper or plastic. For example, a dinner plate is preferably made of a synthetic plastic material so that it is disposable after use. If desired, the plate may be compartmented, for example, into three compartments comprising one large compartment for the main entree and two smaller compartments for vegetables or other food. A suitable plate may be made of a thennoplastic such as polysytrene foam, with or without other plastic layers adhered to the foam layer. By way of further example and not by way of limitation, the plate may have a downtumed peripheral rim comprised of compressed foam with the degree of compression increasing in the direction of the edge of the rim. One such plate for use in carrying out the present invention is disclosed and claimed in U.S. Pat. application Ser. No. 104,046 filed Jan. 5, 1971 in the name of Donald A. Haase, which is assigned to the assignee of the present invention.
Since the locking lugs extend inwardly of the annular rim 32; the portion of the rim between each pair of locking lugs is spaced slightly above the upper surface of the plate rim 38 as best seen in FIG. 4. This spacing allows for the venting of steam which may emanate from hot foods within the container and prevents the formation of a vacuum within the container while still maintaining the food substantially protected from the atmosphere and retaining heat in the food.
In order to conserve space, it is customary to store various receptacles nested one within the other. Due to various factors, such as rough handling and the weight of the units stacked above a given unit, it is known that such nested containers may become difficult to separate from each other. When the covers 10 of the invention are nested within each other, the reinforcing ribs and the lugs in the rim 32 perform the additional function of preventing excessive nesting of the covers within each other, and thus facilitates destacking of the covers when needed for use.
FIGS. 5 and 6 show that some of the reinforcing ribs, designated a, above the lugs in the rim 32 are shorter than the remaining ribs 20. In FIG. 5 there is one such short rib, and there are three in FIG. 6. If one nested cover is rotated relative to the adjacent cover, the dif ferent length ribs and possibly offset locking lugs of each will not permit the covers to nest excessively.
In the illustrated embodiment, the number of short ribs 20a above a respective locking lug alternates in sequence, i.e., one, three, one etc. If desired, the single short rib 20a of one or two of the three rib and lug units may be offset from the center of the lug, as shown in FIG. 5. This further reduces the possibility that any two superimposed covers will mate exactly with each other.
In stacking the covers, adjacent covers are intentionally rotated relative to each other.
Referring to FIG. 2, it can be appreciated that the flat main portion 24 of the top of the cover is of a size to support the plate of another complete unit of a cover and the plate thereon with the bottom 40 of the superposed plate resting on the top portion 24. To facilitate this superposition, the contour of the connecting portion 26 of the top is configured to accommodate the lower portion of the outwardly inclined side wall 42 of the plate of the superposed unit.
While a presently preferred embodiment of the invention has been shown and described with particularity, it will be appreciated that various changes and modifications may suggest themselves to those of ordinary skill in the art upon being apprised of the present invention. It is intended to encompass all such changes and modifications that fall within the scope and spirit of the appended claims.
What is claimed is:
1. In a container for use in serving food and having a dish for holding food, the improvement comprising a plastic cover disposed on said dish, said cover having a lower rim provided with a plurality of spaced inwardly projecting lugs, said lugs engaging the outer periphery of the top of said dish to detachably lock said cover to said dish, said lugs being disposed to space the remaining portions of said annular rim out of contact with the outer periphery of said dish to enable venting of vapors from the interior of said container.
2. A container according to claim 1, wherein said dish is made of plastic, and the outer periphery of said dish has an edge which is deflectable to enable said lugs to engage the outer periphery of the dish in locking relationship.
3. A container according to claim 1, wherein said cover has an annular side wall which slopes inwardly and upwardly and includes a plurality of flutes, said flutes having upper ends which extend inwardly and merge into upper side wall portions, and said flutes being separated from each other by reinforcing ribs.
4. A container according to claim 1, wherein said cover has a top comprising an elevated annular rim, a generally flat top main section connected to said rim by a curved connecting section, a downwardly inclined portion disposed inwardly of said main top section, and a centrally disposed recessed handle.
5. A container according to claim 4, wherein said handle has a knob-like configuration.
6. A container according to claim 4, further comprising reinforcing ribs extending throughout top of said cover and continuing down an annular side wall portion of said cover to adjacent said annular rim.
7. A container according to claim 1, further comprising vertically extending reinforcing ribs provided in the side of said cover, at least some of said ribs being shorter than the remainder of said ribs to limit the extent of nesting of one cover within another upon stacking a plurality of covers together.
8. A container according to claim 7, wherein at least some of said shorter ribs are disposed above at least some of said lugs.