Piggyback microwave container

A piggyback food container having a polymeric bowl forming a first food compartment and a removable cover thereover, a polymeric overcap on said bowl forming a central second food compartment and a peripheral wall, a breakaway juncture between this central compartment and the peripheral wall, enabling the wall to add volume capacity to the uncovered bowl.

BACKGROUND OF THE INVENTION 
This invention relates to a food container, and more particularly to a 
so-called piggyback type microwave container for separated food components 
to be mixed together prior to use 
In general, piggyback containers capable of enabling separate food 
processing of the components and retention of the separated food 
components in individual compartments for ultimate mixing thereof are 
known in the art. In U.S. patent application Ser. No. 228,623, filed Aug. 
4, 1988, U.S. Pat. No. 4,883,955 and entitled A SEABLE RECOMBINABLE 
MULTI-T CONTAINER WITH SEATELY SEALED CHAMBERS, is disclosed a 
container wherein the separate food components are ultimately mixed 
together in the lower compartment just prior to use, the upper container 
serving as an overcap to close the lower container. That multi-part 
container included a special seam ring which projects upwardly around the 
periphery of the lower compartment so as to increase the volume capacity 
thereof for ease of mixing components. Increasing the volume capacity of 
the lower compartment is particularly advantageous to enable easy, rapid 
mixing of the two food components together therein, and subsequent 
processing such as heating in a microwave oven. 
SUMMARY OF THE INVENTION 
The present invention provides a multi-part or so-called piggyback 
container which not only allows separate pretreatment and separate storage 
of two food components, but also provides a unique breakaway feature in 
the upper container component, achieving greatly increased volume capacity 
for convenient mixing of the food components and processing thereof as by 
microwave heating, yet no separate seam ring need be employed just prior 
to use. 
The unique container enables shipping, handling and display of the product 
components in the separate compartments, followed by consumer separation 
of the container compartments and food components for unsealing and mixing 
thereof This involves separation of the upper food compartment from the 
lower one for unsealing the lower compartment, and breakaway of the 
central part of the upper food compartment from its peripheral outer wall 
such that this outer wall can be retained in engagement with the lower 
compartment to greatly increase the volume capacity thereof for most 
convenient mixing, and for processing of the mixed components as in a 
microwave. 
The multi-part container is capable of mass production so as to minimize 
cost. No added seam ring is required. The various parts of the container 
can be fabricated of known materials such as moldable polymers. The 
container is simple to use, yet effecting substantially increased volume 
capacity for ease of mixing and treatment. 
These and several other objects, advantages and features of this invention 
will become apparent to those in the art upon studying the following 
detailed description in conjunction with the drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to the drawings, the complete container 10 (FIG. 4) comprises 
a lower bowl member 12 and an upper overcap member 22, each of which 
initially retains one of the food components in a manner to be described 
hereinafter. Lower bowl 12 includes a bottom 13 and an integrally joined 
peripheral upstanding wall 15 terminating in an upper rim 16 which 
projects upwardly and outwardly. This bowl forms a compartment 14 for a 
first food component such as a food component which requires high 
temperature processing as in an autoclave. This container has an open top 
18 (FIG. 1) which is closed after filling and prior to shipment by a cover 
or lid 19 of conventional thin metal e.g. aluminum, or paper stock for 
easy removal by a consumer. This cover includes a peripheral seam portion 
19a interengaged with peripheral rim 16 of bowl 12, as shown in FIG. 2, 
wherein the cover and rim are rolled into mutual engagement with each 
other. 
Typically, the lower container with its contents and its cover in place 
will be subjected to a thermal processing operation such as autoclaving. 
The lower member may be molded of a polymer such as polypropylene. 
The upper overcap member 22 is also of a polymeric material such as high 
density polyethylene It includes a peripheral outer wall 24 which has at 
its lower end connecting means 30 for sealingly engaging with the rim of 
bowl 12. This connecting means is a resilient, flexible sealing connector 
shown as an inverted U-shaped component 29 (FIG. 8) with an annular 
inwardly facing snap rib 31 on the outer leg of the U, to engage around 
and beneath the periphery of rim 16 which forms the cooperative connecting 
means. In the event that cover 19 of bowl 12 is of metallic material, the 
depending outer skirt 33 of this U-shaped component 30 on upper member 22 
also serves to cover any metal retained on the rim when the bowl is 
opened, so that the metal will not interfere with microwave heating to be 
conducted on the mixed food components. 
Overcap 22 includes a central depression formed by a depending peripheral 
wall 32 integrally formed with a bottom 33 to define chamber 34 for a 
second food component. This upper compartment has an upper rim 38. This 
central depression compartment 34 will have a sealed cover thereover as of 
thin metallic or paper material adhered to rim 38 to seal the second food 
component therein. Peripheral wall 24 is shown to have an annular top 26 
thereon. Between annular rim 38 and annular top 26 is a frangible annular 
ring juncture 40 made to have a breakaway characteristic. Specifically, 
referring to FIG. 7, this juncture 40 is of less thickness of polymeric 
material to allow fracture along this juncture for breakaway of the 
central portion of component 22 from the outer peripheral wall 24 thereof, 
by downward manual force of a predetermined amount. In the preferred 
embodiment depicted, the polymeric components, as noted, are of high 
density polyethylene such as the material designated 52053N from Dow 
Chemical Company, Midland, Mich., capable of being molded into the members 
set forth. In the preferred embodiment, the thickness of juncture 40 is 
approximately 0.010 inch as compared to a thickness of the adjacent 
portions of approximately 0.025 inch. Thus, the preferred thickness of the 
breakaway juncture is less than one-half that of the adjacent material. 
Further, the adjacent material has added strength and rigidity due to the 
convexly curved peripheral wall on the outer periphery of the juncture, 
and the vertical offset in the rim on the inner periphery thereof. This 
vertical offset not only adds strength and rigidity but also raises the 
rim sufficiently to enable manual force to be readily applied thereto. The 
horizontal 1 orientation of the juncture allows vertical force applied 
down on the rim to subject the juncture to shear, for breakage, thereby 
separating the central portion of the upper member from the peripheral 
wall portion thereof. This separation creates an opening where the central 
portion was located. The bottom of upper member 22 is open at 28, i.e., 
within the confines of connection 30 and beneath the central portion. 
Thus, when the central portion is removed, the structure is open from the 
top of wall 24 to the lower compartment 14. 
Breakaway of the central portion of member 22 ca be achieved either while 
upper and lower components 22 and 12 are still connected with each other 
or, if desired, after upper component 22 is separated from lower component 
12 by disengaging the peripheral connecting means 30 and 16. If the 
breakaway function is achieved after the two are separated, then, prior to 
mixing the second food component with the first one, peripheral wall 
portion 24 of upper container 22 is again reattached to lower container 
12. After breakaway of the center portion of component 22, the cover or 
lid is removed from the upper container and the contents thereof poured 
through the new opening remaining at juncture 40 and down into compartment 
14. 
In use, the food manufacturer fills lower bowl compartment 12 with a first 
food component through open top 18 of the bowl, places cover 19 thereover, 
secures it at its periphery with an adhesive heat seal or a conventional 
seaming process, and subjects the food to any desired processing such as 
thermal autoclaving. A separate food component is placed in compartment 
34, typically a food which does not require the high temperature 
processing operation, with the open top of compartment 34 then being 
closed by a sealing cover (not shown) adhered to rim 38. Upper member 22 
is then peripherally attached to lower member 12 by engaging the 
connecting means 16/30 therebetween. The separated product is then shipped 
as a unit package to the retailer where it is displayed in like fashion. 
Upon purchase of the item by a consumer, upper member 22 is separated from 
lower member 12, cover 19 is removed from lower member 12 to open lower 
compartment 14 at 18, breakaway juncture 40 is disjointed by applying 
manual force to the central part of member 22, with or without the 
peripheral wall 24 attached to the lower container, the cover is removed 
from the upper compartment 34, and the contents of compartment 34 are 
poured into the opening left by the breakaway at 40, to mix such with the 
contents of lower compartment 14. The peripheral wall 24 above lower 
container 12 adds considerable increased volume capacity so that mixing of 
the two components can be readily achieved without spilling Further, the 
mixed components can then be subjected to microwave heating or the like 
without spillage. 
Certain additional features not specifically cited may appear to those in 
this art upon studying this disclosure. In addition, certain details of 
construction could be modified without departure from the concept 
presented. Hence, the invention is intended to be limited not to the 
specific preferred illustrative embodiment set forth, but only by the 
scope of the appended claims and the reasonable equivalent structures to 
that set forth therein.