Food Service Tray

Abstract

A food service tray made of polyurethane foam coated throughout its exterior with an epoxy, includes a base and cover, each having cavities therein in registry with cavities of the other for receipt of conventional dishware and flatware, each cavity having a perimetrical thermal barrier around it to minimize lateral heat transfer, each tray assembly having projections in its cover and recesses in its base facilitating stacking in vertical columns, one of the cavites in the cover being aligned with the lug projecting up from the top thereof, to facilitate stacking covers vertically, prior to mounting on bases, a reflective shield being provided in the facing surfaces of the base and cover.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to thermally insulated containers, and more particularly to containers adapted to food and beverage services.

2. Description of the Prior Art

There is a considerable amount of prior art in the field of insulated containers for food and beverage services and for other purposes. Specific examples of which we are aware in the issued patents are as follows:

3,107,027 Sheng-Chiao Hong Oct. 15, 1963 3,114,457 Knapp et al. Dec. 17, 1963 3,295,737 Page et al. Jan. 3, 1967 3,305,124 Whiteford Feb. 21, 1967 3,305,126 Cease Feb. 21, 1967 3,305,283 MacKay Feb. 21, 1967 3,342,397 Duitsman Sept. 19, 1967 3,401,863 Earl Sept. 17, 1968 3,532,247 Bridges Oct. 6, 1970 3,601,277 Andrews et al. Aug. 24, 1971 3,608,770 Naimoli Sept. 28, 1971 Des. 219,204 Bridges et al. Nov. 17, 1970

While the foregoing references disclose various ways and means of insulating trays, stacking trays, and arranging recesses therein, none of them is believed to provide an optimum combination of features.

It is therefore a general object of the present invention to provide a method and means of increasing the efficiency of food service department, by enabling the department to serve food and beverages at proper temperatures with fewer employees, more specifically implemented by a food service tray having insulating features and stacking features enabling longer periods to be taken for food/tray assembly, and storage, and service to patients, in the health-care industry, guests in the hotel/motel industry, students in the school lunch programs, customers in the airline industry, and the like.

SUMMARY OF THE INVENTION

Described briefly, in a typical embodiment of the present invention, there is a multi-compartment insulated food and beverage service tray incorporating a type of barrier or seal which occludes each food compartment opening, thus minimizing lateral (and vertical) transfer of heat from one compartment to another, and thus minimizing temperature change of the contents of any compartment over an extended period of time.

In the preferred embodiment, the user can place all food, beverages, and flatware for a complete meal within the confines of the tray, utilizing conventional sizes and shapes of permanent or disposable dishwater. The height, depth and length of the tray is such that it will fit in standard tray carts and in institutional dishwashers.

Stacking lugs are provided to enable stacking the tray assemblies in vertical columns, and also to enable stacking of covers conveniently, separate and apart from the tray bases. The shapes of the cover and base is distinctive, making the correct orientation thereof readily recognized for convenience of assembly of the cover to the base, and enabling placement of the base and of the cover in the dish rack of an institutional dish washing machine, without tipping either the base or cover.

Both the base and cover are made of material having high thermal insulation properties but having an exterior surface of suitable durability and cleanability the entire unit being sufficiently temperature resistant to avoid burning, and to avoid damage when exposed to the level of temperatures necessary for proper sterilization.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view of a food service tray assembly according to a typical embodiment of the present invention.

FIG. 2 is an elevational view of the assembly of FIG. 1.

FIG. 3 is a top plan view of the base half of the assembly, the cover being removed.

FIG. 4 is a section through the assembly of FIG. 1, taken at line 4--4 in FIG. 1 and viewed in the direction of the arrows.

FIG. 5 is an elevational view, on a smaller scale, showing two tray assemblies stacked, with the cut-away portion showing an interlocking lug and socket.

FIG. 6 is an enlarged fragmentary section of the base showing recesses disposed for reception of a menu clip.

FIG. 7 is an enlarged fragment of FIG. 4 showing the section through the thermal barrier or seal between the dinner plate compartment and soup bowl compartment at the point of nearest proximity of the one compartment with the other compartment.

FIG. 8 is an elevational view of two stacked covers.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings in detail, the illustrated embodiment of the food service tray assembly as shown in FIG. 1 is generally rectangular in shape, but one corner is provided with an angle as shown at 11, and this angle is provided on the face 12 of the cover and face 13 of the base, as indicated more specifically in the elevational view of FIG. 2. It facilitates quick recognition of the correct orientation of the cover with respect to the tray, and, together with a feature described hereinafter, facilitates placement of the cover and of the base in the dish rack of institutional type dishwashing machines, without tipping.

The parting line 14 between the cover and base is also the line at which the conventional type of tray permits considerable lateral heat flow from one compartment therein to another. The present invention has provisions for avoiding this, as will be described more fully hereinafter.

Referring further to FIG. 1, along with FIG. 2, there is an upwardly projecting lug 16 on the top of the cover and another upwardly projecting lug 17 on the top of the cover, horizontally spaced from lug 16. Lug 16 has two legs 18 and 19 extending horizontally in different directions and in this embodiment, they are shown extending at 90.degree. with respect to each other.

Another exterior surface feature of the cover is the stepped down portion 21 extending along the side of the tray at a lesser overall height than the major area 22 of the top. Similarly, in the base of the tray there is a stepped up portion providing a surface 23 closer to the parting line 14 than is the major area 24 of the bottom of the base. These features can be best appreciated by referring to FIG. 5. It provides a small enough thickness dimension (2 inches or less) to adapt the tray and the cover to separately fit the dish racks of institutional dishwashing machines. It also facilitates identification of one tray assembly from another in a stack, and also facilitates the separation of one tray assembly from another in a stack by providing a finger receiving space 25 between each tray assembly and that next above it.

While referring to FIG. 5, it should be noted that the lug 16 on the cover of the lower tray assembly is received in a recess or socket in the bottom of the base of the upper tray assembly. Similarly the lug 17 of the cover of the lower tray assembly is received in a recess or socket in the base of the upper tray assembly. This mating of lugs and sockets between the upper and lower members of succeeding tray assemblies facilitates secure stacking of made-up trays prior to, during, and subsequent to loading in a serving cart or the like.

Referring now to the top plan view of the base as shown in FIG. 3, the various cavities can be identified by reference letters as follows:

A dinner plate cavity

B soup Bowl cavity

C hot Beverage cavity

D milk carton cavity

E juice Glass cavity

F flatware cavity

G bread cavity

H condiment cavity

I salad cavity

J dessert cavity

A thermal barrier to lateral flow of heat into or out of certain of these cavities is provided in the form of a lip or bead completely surrounding the cavity. For example, for the dinner plate cavity A, there is a bead 26 projecting upwardly from the top surface 27 at the parting line 14. The nature of this bead is best shown in FIGS. 4 and 7. Typically this bead rises to a point one-quarter inch above the parting line and, as best shown in FIG. 4, it projects into cavity AA of the cover which is in registry with caviy A of the base, and is in contact with the wall of the cavity AA completely around the perimeter of the cavity. Thus it provides a perimetrical thermal barrier preventing or at least minimizing heat transfer laterally (in the plane of the parting line 14) from or to the dinner plate cavity defined by the registering cavities A and AA. This same type of perimetrical thermal barrier is provided between the registering cavities B and BB for the soup bowl cavity, registering cavities for the salad, dessert, milk carton and juice glass. It can also be provided by the registering cavities C and CC of the hot beverage cavity, if desired.

As shown in FIG. 4 and better shown in FIG. 7, at the location of nearest proximity of the dinner plate compartment to the soup bowl compartment, the bead 26 of the dinner plate cavity and the bead 28 of the soup bowl cavity, are disposed on opposite sides of the wall portion 29 of the cover located between the dinner plate cavity and soup bowl cavity thereof. The overlapping faces of the lips and wall are in occluding relationship, not only minimizing or precluding lateral heat transfer between cavities, but also minimizing or precluding lateral transfer of air, vapors and the like from one cavity to the next. Accordingly there is no intermixing of flavors of the contents of the tray assembly.

As mentioned above, the covers can be stacked separately, prior to assembly thereof with the trays. In this connection a comparison can be made of the location of the lug 16 in the cover of FIG. 1, and the location of the corner 31 in the bread cavity of the base. The cover has a bread cavity in registry with the cavity G of the base. The inside faces 34 and 36 (FIG. 8) of the corner of the bread cavity in the cover, are in vertical alignment with the inside faces 32 and 33 respectively of the corner 31 of the bread cavity in the base, and these are in vertical projection with the outside faces of the legs 18 and 19 of the lug 16 in the cover. Therefore it will be recognized that when one corner is placed on top of another cover, the lug in the top of the cover below will be received in the bread cavity corner of the cover above and thereby provide for vertical stacking of the covers with respect to one another. Similarly the cover has a recess in the underside thereof immediately under the lug 17 thereof to receive the lug of a cover immediately below it when the covers are stacked together. Thus a stable stack of covers can be provided. This is represented in FIG. 8 by way of example. When the covers are stacked, the outer face of the leg 19 of the lug 16 is piloting on the wall 36 of the bread cavity GG in the cover, and the outer face of the leg 18 of the lug is piloting on the face 34 of the corner in the cavity GG of the cover.

As shown in FIG. 6, the edge of the base has a recess at 37 therein adjacent the bottom, and a recess at 38 therein adjacent the top surface at the parting line 14. These recesses are adapted to receive the lugs 39 and 41, respectively of a menu clip 42, facilitating attachment thereof to the base.

The material employed throughout the base and cover must have good insulating qualities, durability, smooth and sanitary and durable surfaces, resistance to damage from heat under sterilizing temperatures, non flammability, light weight and low cost. An example of a material exhibiting such characteristics is a polyurethane rigid closed cell foam. Desirable characteristics of such material are a density of four to eight pounds per cubic foot, tensile strength of 90 to 250 pounds per square inch, compression strength at ten percent deflection of 70 to 275 pounds per square inch, maximum service temperature of 320.degree. Fahrenheit, a thermal conductivity of 0.15 to 0.21 Btu per square foot per hour per degree Fahrenheit per inch, a coefficient of linear expansion of 4 .times. 10.sup.-.sup.5 inches per inch per degree Fahrenheit, a dielectric constant of 1.10, and a dissipation factor at 28.degree.C of 0.0018. It also should have characteristics of self extinguishing in the event of application of a blaze thereto and, as specified by the ASTM Standard D1692-59T, it would qualify as burnable but self-extinguishing when compounded.

As examples of sizes of the compartments, the dinner plate cavity would typically be 9 inches in diameter or slightly greater than that to accommodate all standard dinner plates up to 9 inches in diameter. The soup bowl compartment is large enough to accommodate all 10 ounce conventional soup bowls and is 6.54 inches in diameter or slightly greater. The milk compartment is large enough to accommodate one half-pint milk carton. The juice compartment will accommodate four ounch juice glasses. The salad compartment will accommodate all conventional six inch diameter round salad plates, and is 6.47 inches in diameter or slightly greater. The dessert compartment will accommodate standard institutional dessert dishes and is 4.92 inches in diameter or slightly greater. The diameters are given at the level of greatest diameter in the compartment. Typically the stacking lugs would 31/2 inches long for lugs 17, five/sixteenth inch wide and one quarter inch high. The chevron shaped stacking lug 16 would be of similar dimension.

The foam material has been described above. preferably it is coated on the exterior by an epoxy coating. Although a coating comprising a single coat of epoxy (sprayed on, for example) may be suitable, a coating comprising at least two coats is preferred. This is best represented in FIG. 7 where the outermost coating 43 facing the cavities is a transparent epoxy. This covers a heat shield or reflective shield 44 which covers the first epoxy coating 46. On the bottom of the base and on the top of the cover, there need be only one or two coats of epoxy the first coat possibly containing the color, and the outer coat being clear. The radiation shield is a shiny metallic layer which may be applied by vacuum metallizing electro-plating, metallic painting, stamped sheet foil, a polyester film or other film coated with aluminum. As suggested above, the shield would be placed directly on the epoxy base coat and not directly on the foam. It will be noted from the various illustrations, that there is both a thickness of the foam material and the reflective barrier or shield, between the top of each cavity in the cover and the outside top of the cover, and between the bottom of each cavity in the base and the outside bottom face of the base. Thus the present invention is well adapted not only to minimizing lateral heat transfer, but also to minimize vertical heat transfer.

While the invention has been disclosed and described in some detail in drawings drawwings and foregoing description, they are to be considered as illustrative and not restrictive in character, as other modifications may readily suggest themselves to persons skilled in this art and within the broad scope of the invention.

Claims

The invention claimed is:

1. A food service tray assembly comprising:

a. a base, said base comprising a urethane foam shape of a polyurethane rigid closed cell foam, said shape having at least one coating all over the exterior of the foam;

b. a cover different from said base and mounted on top of said base; said cover comprising a urethane foam shape of a polyurethane rigid closed cell foam, said shape having at least one coating all over the exterior of the foam;

c. said base having a plurality of cavities therein, said cavities being of a size and shape to accommodate conventional sizes and shapes of permanent and disposable dishware;

d. said cover having a plurality of cavities therein;

e. each of said cavities of said cover being in registry with one of said cavities in said base to form a food storage compartment;

f. said cover and base having mating perimetrical thermal barriers around certain of said registering cavities, to inhibit lateral heat transfer between adjacent cavities;

g. said coaver having means to inhibit vertical heat release from said food storage compartments;

h. the overall height of said assembly being less for a distance along at least one margin thereof than elsewhere to provide, in a stack of assemblies, finger receiving spaces between each assembly and the assembly next below it, and to facilitate reception of said cover and said base separately in the dish rack of an institutional dishwasher machine; and

i. wherein one side of said assembly is irregular with respect to the others to facilitate identification of correct registry of said cover with said base in assembly thereof;

said cover having lug means projecting upward therefrom, and said base having upwardly extending recess means therein,

whereby said assembly is securely stackable with like assemblies, the lug means of said cover projecting into the recess means of the base of the assembly next above it, and the recess means of said base receiving the projecting lug means of the cover below it;

one of said cavities in said cover having a corner therein disposed in vertical projection with a corner in said one lug, whereby a plurality of covers like said cover is stackable, with the upwardly projecting one lug of each received in the corner of a cavity of the cover next adjacent thereto.

2. The assembly of claim 1 wherein:

the horizontally spaced lugs are confiningly receivable in recesses in a like cover of another tray assembly.