U.S. patent number 3,876,130 [Application Number 05/413,482] was granted by the patent office on 1975-04-08 for food tray with integral cover.
This patent grant is currently assigned to Mobil Oil Corporation. Invention is credited to Donald A. Haase.
United States Patent |
3,876,130 |
Haase |
April 8, 1975 |
Food tray with integral cover
Abstract
A foamed plastic food tray having a cover of the same material
hinged to one side of the tray is formed with a simple, secure
latch constituted by a portion of a strengthening rim about the
periphery of the tray and a slot in a depressed flute of a skirt at
the front of the cover.
Inventors: |
Haase; Donald A. (Penfield,
NY) |
Assignee: |
Mobil Oil Corporation (New
York, NY)
|
Family
ID: |
23637397 |
Appl.
No.: |
05/413,482 |
Filed: |
November 7, 1973 |
Current U.S.
Class: |
229/406;
220/4.23 |
Current CPC
Class: |
B65D
1/36 (20130101) |
Current International
Class: |
B65D
1/34 (20060101); B65D 1/36 (20060101); B65d
001/00 (); B65d 005/66 () |
Field of
Search: |
;229/2.5,29M,44R,44M
;220/31 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Christian; Leonard D.
Attorney, Agent or Firm: Huggett; C. A.
Claims
I claim:
1. In a package of the class described:
a. a vessel segment to contain a packaged product defined by a
bottom wall and side walls integral with said bottom wall along the
edges thereof, said side walls being arranged to diverge from each
other away from the bottom wall, a flange integral with said side
walls at their edges remote from said bottom and extending
outwardly from the axis of said vessel in a plane substantially
perpendicular to said axis;
b. a cover segment having top wall, side walls and flange
substantially as described with respect to said vessel and a hinge
connecting said segments between the flange on one side of the
vessel and the flange on one side of the cover and adpated to cause
the flanges of vessel and cover to come into aligned registry with
each other upon relative rotation of the cover about the hinge
toward the vessel;
c. a skirt extending from the flange of one of said segments from
the outer edges thereof free of said hinge in a direction away from
said segment;
d. a recessed surface extending across the face of said skirt
remote from said hinge providing a flute across said face and
adapted to ride over the opposing portion of the vessel flange upon
closure of the package; and;
e. a slot across said flute adapted to receive said opposing
portion of the flange of the other segment upon closure of the
package and thereby provide a mechanical latch inhibiting casual
opening of the package.
Description
FIELD OF THE INVENTION
The invention is concerned with a preformed package of general
utility but particularly adapted to enclosure of prepared foods.
Illustrative examples herein include packaging of complete meals
and of hot sandwiches such as hamburgers or other fillings of
sandwiches utilizing buns.
Prepackaged prepared foods are presently available in a great
variety of contained food products and nature of packages. Frozen
foods, either raw or prepared, must be enclosed by means which
inhibit transfer of gases and vapors, for example to prevent
excessive loss of moisture resulting in "freezer burn." It will be
recognized from the description hereinafter that the package of
this invention is not inherently vapor-tight, in fact, for some
purposes herein discussed, it is desirable to afford a substantial
measure of ventilation. Such packages may be enclosed by bags,
coated wrappers or the like known in the art, if freezing is
desired.
The invention is, accordingly, more in the field of permeable or
ventilated packaging which may be optionally wrapped for freezer
storage. Such packages may contain sandwiches, such as those on a
bun in which the filling is any one of a variety of tasty meats and
other foods, e.g., hamburgers, cheeseburgers, barbecued beef or
pork, chicken, fish, sliced beef, etc. Depending on the election of
the consumer, the so packaged food may be consumed immediately on
the sales premises (where permitted); carried to automobile, home
or picnic grounds for consumption after a relatively short
interval; stored under refrigeration for consumption within a few
days; or frozen for storage over a longer period of time to be
consumed at a time suiting the convenience or emergency of the
consumer.
More or less complete meals are also prepared in package form,
e.g., the sidely sold frozen packages commonly referred to as "TV
Dinners" which may be heated in the metal trays of the package when
desired. More recently, institutional and industrial food suppliers
have made use of disposable compartmented serving containers in
which each of several foods intended for consumption at the same
meal by one person is filled into a separate compartment of the
tray or dish-like container. These are convenient for dispensing
lunches and other meals at schools, industrial cafeterias, and
other similar facilities. The technique is also applicable to use
in galleys of planes, trains and watercraft, particularly
sight-seeing boats.
Some of such packages use metal trays or dishes, generally
aluminum, of light gauge and low cost, suitable for discard after
consumption of the contained food. Such packages are heated, when
desired, in radiant heat ovens over a period of time suitably long
for raising the interior of the food to a desired elevated
temperature without application of such intense heat radiation as
to adversely affect the surface of the food. These metal packages
are not suited to rapid heating in microwave ovens.
Other known food packages are bags of metal foil, paper, plastic
film and the like. These are very effective for "carry-out" foods,
such as hamburgers. They provide essentially no protection of
physical integrity of the contained food and must be handled with
care to avoid abrasion, crushing or other mechanical impairment of
surface, form and arrangement of elements of the food, all of which
are detrimental to the original appetizing appearance of the food,
if not of its nutritive value.
Plates and other dishes of greater depth are often formed of pulp
or plastic. A more recent development, described in U.S. Pat. No.
3,684,633, Haase, provides a variety of tableware which is
thermoformed of foamed plastic having a layer of plastic film on at
least one surface. The technology so described is applicable to
formation of plates, bowls, cups, saucers, in fact of tableware
generally. Covers suitable for such vessels are described in
copending application of N.D. Commisso, Ser. No. 271,864, filed
July 14, 1972.
The rigid dishes of plastic, like those of china, glass etc.,
intended for repeated reuse may be covered by a sheet of protective
material, such as foil, paper or plastic film to protect the
contents from contamination. Such fragile elements leave the
contents subject to physical damage or disarrangement, though to a
lesser extent than the three-dimensional insecurity found with
bags, as above described. Relatively rigid covers for permanent or
disposable vessels are available in a variety of materials. These
separate covers are inconvenient at best. A greater disadvantage is
found when it is attempted to use separate vessels and covers in
the preparation and dispensing of prepared foods on a large scale,
as practiced by roadside "hamburger shops." In such environment,
the use of separate vessels and covers is grossly wasteful of time
in requiring that the packager draw from two separate sources of
supply of packaging elements.
Food packages have been made by concurrent thermoforming of a lid
and tray portion joined by an integral hinge and characterized by
matching surfaces. These have been provided with such fasteners as
a tongue projecting from one member engageable by an opening cut
into the other whereby closure is effected.
SUMMARY OF THE INVENTION
The invention provides a packaging system uniquely suited to the
needs of dispensers of food in large volume. This and other
desirable objectives are achieved by an integral food-containing
vessel and cover therefor joined by a linear hinge portion. Both
vessel and cover are of generally similar outline in cross-section.
The vessel is provided at its upper, open edge with a flange
extending outwardly of the vessel in a plane generally
perpendicular to the central axis of the vessel. The flange serves
two important purposes. The flange, together with the side wall of
the vessel, provides a strengthening structure because lateral
pressures against the side of the vessel will be strongly resisted
by this web in a plane parallel to the applied stress. The flange
also serves as a protection against contamination of the contents
of the closed package in a manner presently to be described.
The cover of the package according to this invention is also
provided with a circumferential flange which strengthens the cover,
and hence the package as a whole, in a manner analogous to the
effect of the flange about the vessel portion as described above.
The flange about the cover is provided with a dependent skirt at
the outer edge of the cover flange, which skirt extends about those
portions other than the hinge. By this arrangement, two flanges in
contact provide a means for restricted ventilation which avoids
contamination while permitting enough flow of air to avoid
development of a "soggy" condition. The skirt about the flange of
the cover extends over the joint between the flanges of the vessel
and cover thus inhibiting flow of suspended solid contaminants
present in the atmosphere to the interior of the package. It will
be apparent that two facing flanges provide a channel of air flow
of high pressure drop, insuring that rate of air flow shall be low.
The skirt about the joint (depending from the upper, or cover,
flange) assures that such slow air flow shall cause dropout of
solid contaminants at the exterior of the package.
The security of closure in the package of this invention is
provided by a positive mechanical latch as compared with the
friction closure arrangement of other techniques for closure. A
flute extending across the skirt at the front of the cover is
provided with an opening adapted to receive the flange about the
vessel. This arrangement affords a mechanical abutment type of
latch and avoids the angular corners and unsupported flaps of other
types of closure.
These and other objects and advantages will be apparent from
consideration of the annexed drawings, taken with the description
thereof below.
THE DRAWINGS
FIG. 1 is a plan view of a package according to the invention in
open position;
FIG. 2 is a view of the same package as in FIG. 1, shown in
elevation;
FIG. 3 is an elevation view of the same package as FIGS. 1 and 2,
but shown in closed position and illustrating the recessed
character of the latch;
FIG. 4 is a fragmentary section through the latch taken on line
4--4 of FIG. 3;
FIG. 4A is an enlarged section of the latch shown in FIG. 4;
FIG. 5 is a fagmentary plan view, similar in nature to that of FIG.
1, of a modified form of the invention providing compartments in
the vessel for packaging a complete meal;
FIG. 5A is a fragmentary section on line A--A of FIG. 5;
FIG. 6 is a plan view, in open position, of a package having
superficial resemblance to the package of this invention but with a
different latch and lacking the skirt;
FIG. 7 is a view in elevation of the closed package illustrated by
FIG. 6; and
FIG. 8 is a fragmentary section on line 8--8 of FIG. 7.
FIGS. 6, 7 and 8 are included for comparison purposes to
demonstrate the advantages of the invention. The structure
illustrated by FIGS. 6, 7 and 8 is not intended to be claimed in
this application.
SPECIFIC EMBODIMENTS OF THE INVENTION
It is a principal object of the invention to provide a package,
particularly for foods, which is readily fabricated on automatic,
high-speed machinery of low cost materials having substantial heat
insulating qualities. It is a further object that the open package,
as supplied for filling and closing shall be nestable in the sense
that a large number of empty packages can be stacked together, each
within the cavities of an adjacent carton, such that the volume
occupied is very little more than the sum of the thicknesses of
walls of the packages. Such nesting results in najor economies in
shipping and storage. It is a further object that the empty
packages be readily denested; that is, the empty packages in a
stack should be capable of easy, rapid and uniformly smooth removal
from the stack at either end for convenience and low cost of the
filling and closing operation.
Further objects contemplate easy latching of the package and a
secure mechanical detent when latched. It is further contemplated
that the package shall be easily opened when desired and that it be
capable of reclosing and reopening many times without substantially
impairing security of closure.
The invention has, as additional objects, a rugged structure
resistant to mechanical damage and capable of protecting the
contents of the closed package against air-borne contamination
without major inhibition of ventilation; it being understood that
the package may be totally enclosed by films or like which are
impervious to gases and vapors. A still further object is of
particular importance when the package is so enclosed. That further
object is provision of a package free of sharp corners and spurs on
its exterior to avoid damage to the carton by "catching on" fabrics
or projecting elements and to avoid danger of puncture to enclosing
films.
The achievement of all these objectives simultaneously requires a
particular combination of structural elements as provided by this
invention. Constraints on available options are imposed by such
features as the need for production on high speed molding machinery
to provide for manufacture at an acceptable cost.
Some features of the present package are also present in the
packages described in my copending applications for design patents
Ser. Nos. 342,224 and 342,240, both filed Mar. 16, 1973.
Typical materials of construction which will provide the desired
heat insulation and strength are foamed resins, such as foamed
polystyrene, and pulp. The former is supplied as a web of foamed
resin to a thermoformer in which the web is heated to a temperature
high enough to permit reformation and drawing operations and is
then pressed between cooled matching molds to the desired form.
Pulp articles are formed from a suspension of paper fibers in water
supplied to a screen conforming to the desired shape. A vacuum
applied to the side of the screen opposite to the supply of water
suspension causes the fibers to felt on the screen in the desired
form. Upon drying, the finished product is removed from the
screen.
Both forming operations here briefly described require that the
form of the article be such that it is readily stripped at high
speed from the forming element with a high degree of assurance.
Faulty stripping of a single article, even to the extent of
misalignment, results in jamming of the machine and costly
shut-down to clear the jam. For that reason, surfaces of the formed
article must be sloped such that stripping involves merely release
from the surface of the forming element, as contrasted with sliding
friction between surfaces parallel to the direction of withdrawal.
There should be no undercuts, unless costly forming elements having
retractable parts are provided.
These limitations on structure arising from the manner of
manufacture are satisfied and the other objects are fulfilled by
packages having features shown in the annexed drawings, wherein
like parts are referred to by the same reference numerals.
A very useful form of the invention is embodied in the "hamburger
package" shown in FIGS. 1, 2, 3 and 4. This structure is adapted
for dispensing of the well known hamburger constituted by ground
beef in a bun and is subject to wide variation by addition of
cheese, vegetables, condiments and the like. The package comprises
a vessel 10 and cover 11. These elements are formed simultaneously
and integral with each other as shown. Along the line of division
between the vessel 10 and cover 11 means are provided to assure
that, on closing, the fold line will be in a predetermined hinge
area to assure registry of vessel and cover. In the embodiment
shown, the hinge line is defined by a compressed hinge line 12 in
the foam, pulp or other material of construction.
The vessel 10 is of generally rectangular shape in horizontal
cross-section with rounded corners and curved, bulging sides formed
by the side walls 13 which slope outwardly in rising from the
bottom 14 to a horizontal flange 15. The flange 15, formed
integrally with the vessel 10, extends across the front and along
the two sides of the vessel 10 and is preferably continued across
the back in a manner to space the vessel 10 from the hinge line 12.
For convenience in removing the contents, the vessel 10 may be
provided with recesses 16 at one or both rear corners, thus
enabling the consumer to insert a finger or fingers behind and
under the contents of the package.
The cover 11 comprises a top wall 17, side walls 18 and flange 19
generally similar to the corresponding elements of the vessel 10 in
size and configuration. At the front and along the sides of the
flange 19 is a skirt 20, which, in the closed position of the
package depends from the flange 19 to overlie and protect the
abutment of flanges 15 and 19 as shown in FIGS. 3 and 4. As best
seen in FIGS. 1 and 2, the edge of skirt 20 converges toward the
flange 19 from front to back and is faired into the surface of
flange 19 at the rear of cover 11.
At the front of the package (remote from the hinge 12) the wall
forming skirt 20 is depressed to form a flute 21 deep enough to
intersect flange 15 of vessel 10. A slot 22 is punched through the
flute at this area of intersection such that, on closure of the
package, the adjacent portion of flange 15 is received in slot 22
for positive latch of the package without the appearance of
elements projecting substantially beyond the pleasingly curved
protecting surfaces of the package. This feature will be clearly
apparent on study of the fragmentary section of FIG. 4.
As seen in FIG. 5, the invention may be applied to a variety of
package configurations and purposes. In the embodiment of FIG. 5,
the vessel is more sharply rectangular than in FIG. 1, though it is
still preferred that corners be rounded as shown. The FIG. 5
package is adapted to contain a complete meal and, for that
purpose, the vessel 10 is divided into three compartments by
partitions 23 and 24 molded into the bottom 14, as by forming a
double wall at each partition area. See FIG. 5A.
Referring now to FIGS. 6, 7 and 8, it will be immediately apparent
that the fluted skirt arrangement of this invention is superior in
appearance, security of closure, protection against contamination,
and ease of handling as compared with a closure which is feasible
for flanged cover and vessel elements without the skirt. As best
seen in FIG. 6, this comparative package comprises, as does the
package of the invention, vessel 10 and cover 11 having,
respectively, bottom and top walls 14 and 17; side walls 13 and 18;
and flanges 15 and 19. The closure arrangement is constituted by a
tongue 25 formed by cutting the cover flange 19 and an open ended
slot 26 cut into the vessel flange 15. On closure, the tongue 25 is
drawn down into slot 26 to frictionally engage the sides of slot 26
in the manner shown by FIG. 7.
It will be seen that engagement of the closure in the package of
FIGS. 6, 7 and 8 requires a separate operation in addition to that
of rotating the cover 11 above the hinge line until the flanges 15
and 19 abut each other. The tongue 25 must be displaced from its
position in the flange 19 and manually brought down through the
slot 26. After engagement of the closure the package has only
frictional forces to retain its closed position. By contrast, the
positive latch of this invention automatically engages as the
package is closed and the sloping inner wall of flute 21 rides over
flange 15 until the latter enters slot 22 for positive locking. In
addition, skirt 20 functions to protect against accidental
contamination while permitting escape of water vapor and the like,
as from a hot hamburger and thus avoids development of a soggy
condition of the contained food.
The package of this invention may be utilized in a variety of
different ways. Having regard only to the hamburger package of
FIGS. 1, 2 and 3, it may be applied in dispensing products at
roadside establishments by placing freshly cooked hamburgers in
individual packages as cooking is completed and placing a supply at
hand for prompt sale. The packaged food is adapted to be eaten at
once or at a future time. Freshness will be retained in driving a
short distance, as to a picnic ground. If longer delay is
contemplated, the packaged product is easily reheated by a
microwave oven without removal of the food from the package until
heating is complete. Such microwave reconstitution of previously
prepared (fully cooked) frozen food is a system in which the
invention offers important advantages. This technique is not
restricted to use by individual consumers. For example, hospitals
find it efficient to freeze prepared foods and reconstitute the
meal by microwave heating near the rooms of patients. In this
manner, the food is served hot without being maintained in a heated
cart for periods which result in loss of flavor. Many vessels
available for the purpose have pronounced tendency to "pop" open in
the microwave oven. The positive mechanical latch of the food
container provided by this invention avoids that difficulty.
Alternatively, sandwiches and other foods intended for consumption
hot may be so packaged in the raw state (preserved in a freezer if
desired) and cooked to taste when the occasion arises.
* * * * *