US 3401863 A
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Description (OCR text may contain errors)
Sept. 17, 1968 L. w. EARL COMPARTMENTED TRAY Filed Dec. 12 1966 INVEN TOR. 4 if WALL 4 RL X 3 United States Patent Office 3,401,863 Patented Sept. 17, 1968 3,401,863 COMPARTMENTED TRAY Lee Wall Earl, Easton, Pa., assignor to American Can Company, New York, N.Y., a corporation of New Jersey Filed Dec. 12, 1966, Ser. No. 600,940 6 Claims. (Cl. 229-2.5)
ABSTRACT OF THE DISCLOSURE A fiberboard compartmented tray having a plurality of rib elements in the tray bottom dividing the tray into a plurality of compartments. The bottom of the tray and a peripheral ridge are of less thickness, having been compressed, than the rib elements, thus increasing the trays resistance to bending under load.
This invention relates to plates or trays and more particularly to a more rigidized compartmented tray for holding a quantity of different foods, each being separated from the other by ribs or barriers joined together and to surrounding side walls.
In institutional or mass feeding of large groups of people, it is often desirable to use disposable trays, dishes, and utensils in order to eliminate costly and time-consuming washing and storage problems. In the armed services, compartmented metal trays have been used for many years to handle complete meals while still separating the different types of food from each other. However, the reusable metal trays used in the services necessitated subsequent washing and storage.
There are a number of compartmented trays made of disposable material shown in the prior art, such as in US. Patents 2,738,915 and 3,067,922. These trays are used to hold several different foods such as meats, fish, vegetables, salad and the like, either hot or cold. Due to their relatively small size, complete meals could not be served in these trays. If a complete meal were served, a much larger tray would be needed. It is readily apparent that the larger the tray, the more difficulty is encountered in maintaining it in a rigid condition so it will not bend when filled. A major disadvantage of paper plates .and trays has been their low structural strength.
It is, therefore, an object of the present invention to provide a compartmented tray for holding a plurality of foods, each separated from the other, wherein said tray has increased bending resistance.
Another object of the present invention is to provide a disposable tray which is both inexpensive and resistant to deformation by relatively heavy loads, such as may be encountered when carrying a full meal therein from a serving area to an eating area.
A further object of the present invention is to provide a disposable serving tray of improved structural strength and rigidity.
Yet another object of the present invention is to provide a disposable fibre serving tray of improved'structural strength and rigidity with little or no change in the quantity of material used in its manufacture.
Numerous other objects and advantages of the invention will be apparent as it is better understood from the following description, which taken in connection with the accompanying drawings, discloses a preferred embodiment thereof.
Referring to the drawing:
FIGURE 1 is a fragmentary top plan view of .a blank prior to its formation into a compartmented tray;
FIGURE 2 is a top plan view of a compartmented tray embodying the present invention;
FIGURE 3 is a fragmentary sectional view taken along the line 33 in FIGURE 2; and
FIGURE 4 is a fragmentary sectional view taken along the line 4-4 in FIGURE 2.
As a preferred or exemplary embodiment of the instant invention, FIGURE 1 illustrates a tray blank 10 made of a compressible material such as fibre. Solid bleached paperboard having a weight of 84 pounds per thousand square feet has been found to be preferred in the manufacture of this article. As shown, the blank 10 is in the form of a rectangle and at each corner of the rectangle are formed a plurality of radial scores .12 having a substantially equal length. These scores function in a manner which will be explained more fully hereinafter. Small cutouts 14 are formed in the sides of the blank 10 in order to facilitate forming the tray 15 shown in FIGURE 2.
The rectangular plate or tray 15 has a bottom wall 16, side walls 17, 18, and end walls 19, 20. Forming the periphery of the tray 15 is a curved upper marginal ridge 2.1 which merges with and extends obliquely upwardly from the bottom wall 16. This ridge 21 terminates in an outwardly and downwardly sloping edge 22 (FIG- URE 3).
A plurality of rib elements 23, 24 divide the bottom wall .16 of the tray 15 into a plurality of compartments or separate sections 25, 27, 29. These rib elements 23, 24 preferably are in the form of an inverted V-shape section (FIGURE 4) which are embossed in the bottom wall and may, if desired, extend the full height of the tray, but for the purpose of this invention it is desired that they extend upwardly for a distance approximately halfway of the height of the surrounding side walls. The rib elements 23, 24 terminate at the ridge 21 where the cutouts 14 are formed in the blank 10.
To increase the stiffness of the tray 15, the bottom wall 16 and the side and end walls 17, 18, 19, .and 20, together with the ridge 21, are compressed to a thickness less than that of the rib elements 23, 24. For example, if the thickness of the original blank 10 is 0.024 inch, the thickness of the rib elements 23, 24 are substantially the same as the blank 10, whereas the thickness of the bottom wall 16, the side and end walls 17, 18, 19, 20, and the ridge 21 are compressed to a thickness of approximately 0.021 inch. This results in an increase in density of the fibreboard in the compressed sections and a reduction in thickness of approximately 12 percent. This configuration imparts a stiffening effect which increases the trays bending resistance and produces .a flat rigid tray which is adequate to hold a complete meal without buckling when a fully loaded tray is carried.
In order to prevent objectionable wrinkling in the corner areas of the tray 15 when it is formed from the blank 10, the scores 12 guide the formation of overlapping folds 31 so that some degree of uniformity and spacing of these folds 31 are obtained. These folds 31 are outside the concave surface area of the compartments 25, 27, 29. In addition, the folds 31 are pressed flat against the surface of the ridge 21 and edge 22. Not only do these fiattened folds 31 give a more pleasing appearance, but they also facilitate nesting of the trays in a minimum amount of space, thus reducing storage and shipping volume necessary for a given number of trays.
In order to maintain a service life of approximately one hour, which is necessary for proper utilization of the tray 15, a grease-resistant coating 33 must be placed on the concave surface area of the compartments 25, 27, 29. One such coating 33, which not only increases the resistance of the tray material to grease and liquid penetration, but also provides increased resistance to puncturing by regular table knives during normal use of the tray, is a lacquer coating such as nitrocellulose.
For this coating, a clay and polyvinyl acetate precoat having a weight of approximately one pound per thousand square feet is placed on the surface in order to increase the adhesiveness of a nitrocellulose coating to the fibreboard. Thereafter the surface area of the tray 15 is coated a nitrocellulose lacquer coating 33 having a weight of approximately 0.5 pound per thousand square feet. An alternate for the nitrocellulose coating is an olefin coating of approximately 2 pounds per thousand square feet of polypropelene. However, the costs of olefin coatings are much greated than that of nitrocellulose coatings and are thus probably not economically feasible.
It is thought that the invention and many of its attendant advantages will be understood from the foregoing description and it will be apparent that various changes can be made in the form, construction, and arrangement of the parts Without departing from the spirit and scope of the invention or sacrificing .all of its material advantages, the form hereinbefore described being merely a preferred embodiment thereof.
1. A compartmented tray, comprising:
a substantially fiat bottom wall;
side and end Walls extending obiquely upwardly therefrom and merging into a curved upper marginal ridge peripherally surrounding said tray;
a plurality of rib elements in said bottom Wall extending upwardly therefrom and dividing said tray into .a plurality of compartments;
and said bottom Wall and said marginal ridge being compressed and having less thickness than said rib elements thereby imparting a stiffening effect which increases said trays bending resistance.
2. The tray of claim 1 wherein said tray is rectangular in shape.
3. The tray of claim 2 wherein there are flattened folds, positioned by scores formed in the corners of said upper marginal ridge, in the peripheral corner areas of said marginal ridge.
4. The tray of claim 1 wherein said material is made of low density fibreboard.
5. The tray of claim 4 wherein said bottom wall and marginal ridge are compressed approximately 12% in thickness.
6. The tray of claim 4 wherein at least the concave surface area of said compartments is coated with a nitrocellulose lacquer in order to increase the resistance of the tray material from grease and liquid penetration.
References Cited UNITED STATES PATENTS 1,748,865 2/1930 Chaplin 2292.5 3,033,434 5/1962 Carson 229-2.5 3,067,922 12/1962 Hill 229-25 3,113,710 12/1963 Meagher 2292.5 3,137,436 6/1964 Moors et a1 229-31 DAVIS T. MOORHEAD, Primary Examiner.