Electric heating – Microwave heating – Enclosed cavity structure
Reexamination Certificate
2000-08-03
2002-01-29
Leung, Philip H. (Department: 3742)
Electric heating
Microwave heating
Enclosed cavity structure
C219S725000, C219S392000, C099SDIG014, C126S0390BA
Reexamination Certificate
active
06342693
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to the fields of protective coverings, and specifically, to protecting a microwave oven from food spills and spatter.
BACKGROUND OF THE INVENTION
Microwave ovens are widely used all over the world to heat and cook food items much more rapidly than conventional heating ovens. But the nature of microwave technology is such that in the process of heating food items, the microwaves will often cause the food items to overflow, or to “pop,” which of course, produces a mess along the sides, back and front (interior surface) of the microwave oven that needs to be cleaned with a sponge or similar cleaning apparatus. This entails reaching into the oven and applying “elbow grease” at various awkward angles, and as anyone who uses and has ever had to clean a microwave oven is aware, is tiresome and difficult.
The U.S. Patent literature does disclose some efforts to solve this problem. U.S. Pat. Nos. 4,721,140; 4,785,160; 4,797,523; 4,801,773; and 4,950,859, for example, all disclose various containers, covers, shields, etc., that are placed over or around a particular food item being cooked, in order to block and prevent spills and spatters from that food item from reaching the inner surface of the microwave oven. But these are associated in their use with each individual food item being cooked, rather than with the microwave oven itself. As such, these devices are removed along with the associated food item each time a food item is heated or cooked, and reintroduced into the microwave oven each time a new food is to be cooked.
U.S. Pat. Nos. 4,663,052; 4,778,968; and 5,290,985 improve this situation, since these protective devices are each used in connection with the microwave oven itself, and remain in place to guard against spills and spatter from the cooking of one food item to the cooking of subsequent foods items. After a time, once the protective device has become soiled beyond a certain point, the device is removed and disposed of, and is replaced with a new, similar device.
But microwave ovens are manufactured and sold in many varied sizes, and all of U.S. Pat. Nos. 4,663,052; 4,778,968; and 5,290,985 suffer the common deficiency that they cannot easily be used in connection with varying sizes of microwave oven. Indeed, a survey taken by applicants of over
100
microwave oven models reveals that microwave ovens typically vary in volume from about 0.5 to 1.8 cubic feet, and in linear dimension from a minimum height of about 6 inches to a maximum height of about 15 inches, from a minimum width of about 11 inches to a maximum width of about 21 inches, and from a minimum depth of about 10 inches to a maximum depth of about 18 inches. This survey also reveals that these linear dimensions typically vary by ¼ inch, ⅛ inch, ⅙ inch, or {fraction (1/16)} inch increments. Given this wide size variability from one microwave oven to the next, it would be difficult or impossible to use the protective devices of U.S. Pat. Nos. 4,663,052; 4,778,968; and 5,290,985 for more than a single size of microwave oven, give or take perhaps a fraction of an inch along any one linear dimension. As such, if these protective devices were to be used for all commonly-manufactured oven sizes, it would be necessary to manufacture dozens of different sizes of these protective devices.
In addition, all of these liners are difficult to set up and attach for use inside the microwave oven, and (e.g., U.S. Pat. Nos. 4,778,968, column 2, lines 58-61) even need an independent support structure.
These liners also do not appear to provide suitable protection for the front door of a microwave oven.
Additionally, the choice of materials used to construct a microwave oven liner is very important. Saran-type polymeric materials do not hold up well over time and are meant for one use and then disposed of. They do not have a heat history at all, melting in the presence of steam resulting from cooking food. Cardboard-type material and papers commonly used in paper bag construction are not appropriate either. These materials absorb moisture and spilled foods. This causes them to stick to the microwave interior, defeating their purpose and usefulness.
OBJECTS OF THE INVENTION
It would be desirable therefor, to provide a microwave oven liner which can be configured (resized or scaled) to protect a wide range of microwave oven sizes, encompassing at least the size ranges noted in the background of the invention.
It would further be desirable if this resizing could be achieved at various small increments, permitting the microwave oven liner to be resized to any height from about 6 inches to 15 inches, and to any width from about 11 inches to about 21 inches, and to any depth from about 10 inches to about 18 inches by, for example, not limitation, ⅛ inch increments.
It would further be desirable to provide a simple means to attach the microwave oven liner to the microwave oven, once it has been resized to the dimensions appropriate to the given microwave oven for which it is to be used.
It would further be desirable to provide a means for protecting the front door of a microwave oven, in addition to protecting the sides, top, bottom, and back of the microwave oven.
It would further be desirable to provide a microwave oven liner which is fabricated from a material which has structural integrity and is able to free-stand in the microwave device on its own, requiring minimal or no supports, and without imposing undue setup requirements upon the liner user.
It would further be desirable for the liner to be durable under repeated microwave bombardment and heating, so that the liner remains free-standing after many microwave uses, and needs to be disposed of because of the spilled food that it has prevented from being caked on the microwave surface—not due to the liner becoming deformed from heat.
It would further be desirable for the microwave oven liner not to allow food to be absorbed or soaked into its surface, as this would cause the liner to stick to the microwave surface, defeating its purpose.
SUMMARY OF THE INVENTION
A preferred embodiment of the invention disclosed herein is a pleated microwave oven liner comprising a plurality of semi-rigid liner pleats that enable the microwave oven liner to be expanded from initial dimensions of approximately 6 inches in height by 11 inches in width, to final dimensions as large as approximately 15 inches in height by 21 inches in width, for example, not limitation, by ⅛ inch increments. As such, a single microwave oven liner can be produced which is suitable for use in microwave ovens over a wide range of varying sizes. The depth is varied from approximately 10 inches to 18 inches either by folding over the front of the liner on itself, or by removing part of the front of the liner, e.g. by cutting the liner, or by tearing the liner along perforated tear lines.
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Hogan David
Hogan Elizabeth
Smith Rose Mary
Leung Philip H.
Yablon Jay R.
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