US 3430803 A
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March 4, 1969 P. B. NELSON 3,430,803
SEMIDISPOSABLE TRAY Filed Oct. 2. 1967 FIG. 3
INVENTOR. PAUL B. NELSON United States Patent 3,430,803 SEMIDISPOSABLE TRAY Paul B. Nelson, Aliquippa, Pa., assiguor to Sinclair- Koppers Company, a partnership of Delaware Filed Oct. 2, 1967, Ser. No. 672,231 US. Cl. 220-63 8 Claims Int. Cl. 365d 25/14, 25/34 ABSTRACT OF THE DISCLOSURE A tray is provided, comprising a unitary foam plastic base in combination with a nonfoam plastic guard, which is useful in the serving of comestibles. Following a single use period, the guard may be removed and discarded while the base member can be used for any number of servings, with a clean guard in place. The configuration of the base member provides structural stability for the tray and the guard rests firmly in place when superimposed upon said base member.
Background of the invention Even in todays world of disposable items people often have an aversion to the use of paper or pulp trays and plates. The use of plastic coated paper or plastic material adds cost to the item and is, because of this reason, unattractive. Also, such products tend to dissipate heat rapidly and foodstufis cool much sooner than is desirable. Thus, with the evergrowing number of social gatherings, barbeques, picnics, and camping, a need exists for an economical tray which will combine low cost with aesthetic appearance and insulating properties.
Summary of the invention According to the present invention, an economical semidisposable tray is provided which comprises a foam plastic base member and a nonfoam film guard. The foam base member has a horizontal bottom and an upwardly and outwardly extending lip to form a container. The lips terminate in a downwardly and outwardly extending wall which extends below the plane defined by the horizontal bottom and, when placed on a substrate, positions the bottom so that it does not rest on the substrate. The nonfoam plastic guard has a configuration conforming t that of the base member and is superimposed thereon. The downwardly and outwardly extending wall of the guard, however, terminates so as to expose a portion of the base member wall, perventing lifting or bending of the guard and providing a contiguous fit with relation to the base member.
The objects and novel features of the invention are described by the following detailed description when the same is read in connection with the accompanying drawings. It is to be expressly understood, however, that the drawings are not intended as a definition of the invention, but are for the purpose of illustration only.
Brief description of the drawings In the drawings, wherein like parts are marked alike:
FIGURE 1 is a perspective view of the tray of the invention with a guard removed in phantom.
FIGURE 2 is a partial cross-sectional view of the tray of the invention taken along the line 22 of FIGURE 1.
FIGURE 3 is a perspective view of a plurality of the trays of FIGURE 1 stacked one upon another, showing one container without and two with guards.
FIGURE 4 is an isometric view of another embodiment of the tray of the invention.
Detailed description Referring now to 'FIGURE '1, there is illustrated the base member 1 of the tray of the invention having a substantially horizontally disposed bottom portion 3 and an outwardly and upwardly extending lip 5. The lip 5 terminates in an outwardly and downwardly extending exterior wall 7.
The exterior wall 7 extends downwardly below the plane formed by the substantially horizontally disposed bottom portion 3 as seen in FIGURE 2. This extension of the exterior wall raises the bottom portion 3 so that the bottom portion does not rest upon a substrate upon which the tray rests. This configuration greatly decreases sliding or slippage of the tray on a substrate because of the fact that maximum weight is exerted on an area surrounding the bottom portion and because of frictional forces thereby produced.
Also illustrated in FIGURE 1 is the nonfoam plastic guard 11 of the tray of the invention. This guard 11, has a substantially horizontally disposed bottom portion 13 and an outwardly and upwardly extending lip 15. This lip 15 also terminates in an outwardly and downwardly extending wall 17.
The guard 11 must be of such dimensions that the guard will, when superimposed upon the base member 1, conform with the base member and will rest in contiguous relationship with the base member. However, the outwardly and downwardly extending exterior wall 17 must terminate at a point short of the terminal point of the exterior wall of the base member. By terminating at such a point, there is a portion 9 of the base member 1 exposed. This prevents bending or lifting of the guard from its contiguous relationship with the base member and re sults in a close and adherent positioning of the guard 11 on the base member.
For the purpose of adherence of the guard 11 to the base member 1 and utility of the tray as a food serving tray, the angle a, formed by the bottom portion 3 and lip 5, must be within a specific range. This angle a, as better seen by referring to FIGURE 2, must be within the range of to This range of values for the angle a is needed since a smaller angle, i.e., less than 90 will cause accumulation of foodstuifs or dust in the area formed by this angle. On the other hand, if the angle a is greater than about 160, the guard 11 will not be positioned sufiiciently secure to prevent slippage of the guard under normal use conditions.
As seen in FIGURE 3, the tray has a configuration which allows stacking of the trays when not in use. Such stacking is an essential property of the trays of this sort so as to provide a most compact package and allow the most efiicient use of storage or shipping space. The trays can be stacked both with and without a guard 11 in place, as illustrated.
Another embodiment of the tray of the present invention is shown in FIGURE 4. There is illustrated a base member 1, with a guard 11, both of which have ridges or dividers 21 transverse the bottom portions 3 and 13 respectively thereof. These dividers provide a means for the separation of different types of foodstuffs and, of course, any number of such dividers can be used, depending upon the desired end result.
Also illustrated in FIGURE 4 is a unique aspect of the invention which is the decorating or ersonalizing of the trays. The base member 1 of the tray can easily be decorated (illustrated as 23) as by use of a decal, printing, or the like. By use of a guard 11 which is of transparent or translucent material, the decoration is readily visible. Thus, the base member, being reusable, can be decorated and by using disposable guards, reused any number of times. In fact, the purchaser of a tray of the invention could decorate it as to his desire with little or no problems associated therewith and change the decoration whenever desired. Such decoration can also be made on the underside of the nonfoam film guard by printing and the like or the guard can be colored or opaque. Such use as a promotional item or as a quality item is very effective.
There is also illustrated in FIGURE 4, the use of a tab or projection 25 on the guard 11 which may be used to assist in removal of the guard for disposal. This is not a necessary embodiment, but in some instances, may be desirable. The tab 25 in such a case would be an integral part of the guard.
The material used in the construction of the base member of the tray of the invention may be any suitable foamed plastic material such as polyethylene, polyurethane or polystyrene. Preferably, the container is formed from expandable polystyrene such, for example, as that sold under the trademark Dylite. The base member can be either molded, or formed by a thermoforming process from polystyrene sheet material. The molding of expandable polystyrene is well known and is described, for example, in the article, Expandable Polystyrene, by Edwin A. Edberg in Modern Plastics, Encyclopedia Issue, September 1957, pp. 347-350. Conventional techniques of thermoforming, vacuum forming, and the like are known in the art. Exemplary of such techniques are those described in Koppers Technical Bulletin, Thermoforming Foam Polystyrene Sheet and Polystyrene Foam Polystyrene Laminates, Bulletin C-9-273, chapter 4C, Apr. 15, 1952.
The thickness of the base member is dependent upon the end use therefor. The thickness would also depend upon the density of the foam material. Generally, for low density polystyrene, a thickness of about 80 mils is desirable, but much larger or much smaller thicknesses can obviously be used.
The nonfoam plastic film material used to fabricate the guard of the tray of the invention can be any plastic material which can be formed to the configuration necessary and which will hold such configuration. For example, crystal polystyrene, polyethylene and the like are usable. Especially useful is impact polystyrene, for example, styrene-butadiene copolymers, which will not be scratched or marred easily by utensils. Translucent or transparent films are especially desirable. The guard is also fabricated by thermoforming or the like, by generally known methods. The thickness of the nonfoam plastic film can vary, films in the order of 05-25 mils being preferred.
As an example of the size of such trays, specific trays have been formed having a diameter of about seven inches. Also, trays having the oval shape illustrated in FIGURE 4 have been made having the dimensions of eleven inches by eight inches, length and width, respectively. Specific such trays have been produced where the base member was molded from 5.0 pounds per cubic foot polystyrene with guards thermoformed from 5 mil me dium impact polystyrene. These dimensions and materials are exemplary only of those usable and not meant to be limiting.
There has been described a novel tray comprising a foam plastic base member and a nonfoam plastic film guard. The lightweight, structurally stable tray is especially useful where disposable items are desired. The preferably transparent or translucent guard can be easily and economically disposed of while the base member, possibly containing specific designs or notations can be reused with a subsequent such guard. The guard does not slip or separate easily from the base member during use because of its specific configuration. The trays are easily stacked both with or without guards to allow compact storage or shipping.
What is claimed is:
1. A tray comprising:
(a) a unitary base member of foam plastic material having a substantially horizontally extending bottom portion terminating in an outwardly and upwardly extending lip, said lip terminating in an outwardly and downwardly extending exterior Wall, said wall extending downwardly below said bottom portion;
(b) a nonfoam plastic film guard for said base member, the configuration of said guard having a substantially horizontally extending bottom portion terminating in an outwardly and upwardly extending lip, said lip terminating in an outwardly and downwardly extending exterior wall;
(0) the dimensions of said guard being such that when superimposed on said base member, said guard will rest in contiguous relationship with said base member with said outwardly and downwardly extending exterior wall of said guard terminating so as to expose a portion of the said outwardly and downwardly extending wall of said base member.
2. The tray of claim 1 wherein said outwardly and upwardly extending lips of said unitary base member and said guard form an angle of -160 with said substantially horizontally extending bottom portion of said unitary base member and said guard respectively.
3. The tray of claim 1 wherein said foam plastic material is expanded polystyrene.
4. The tray of claim 1 wherein said base member and guard have ridges transverse to the bottom portion thereof.
5. The tray of claim 1 wherein said guard has, as an integral part of said outwardly and downwardly extending exterior wall, a projection to enable the easy removal of said guard from a superimposed position on said base member.
6. The tray of claim 1 wherein said nonfoam plastic film is impact polystyrene.
7. A foam plastic unitary base member suitable for superimposition of a nonfoam plastic guard thereon, said base member having a substantially horizontally extending bottom portion terminating in an outwardly and up wardly extending lip, terminating in an outwardly and downwardly extending exterior wall, said wall extending downwardly below said bottom portion.
8. A nonfoam plastic film guard suitable for superimposition on a foam plastic base member, the configuration of said guard having a substantially horizontally extending bottom portion terminating in an outwardly and upwardly extending lip, said lip terminating in an outwardly and downwardly extending exterior wall, the dimensions of said guard being such that when superimposed on said base member, said guard will rest in contiguous relationship with said base member with said outwardly and downwardly extending exterior wall terminating so as to expose a portion of said base member.
References Cited UNITED STATES PATENTS 3,159,698 12/1964 Suh et al. 220-63X 3,305,124 2/1967 Whiteford 22063 GEORGE T. HALL, Primary Examiner.