Matsushita Electric Industrial Co., Ltd.

Toshio Kai

Junzo Tanaka

Tsuyoshi Takami

Mamoru Isogai

Hitoshi Kurita

Chikao Urashima

Yoshitomo Fujitani

Self lubricating door key and door hook for high frequency heating

Multi-function oven with control circuit for operation during

The invention is related to improvements in a cooking appliance equipped with both a microwave heating means and a hot air circulation heating means. By controlling the rotational speed of an air circulating fan or the power of heater means according to the kind of food to be cooked, the cooking time is shortened and the quality of cooked food is improved. The hot air discharging section of such an oven includes a perforated plate so as to prevent leakage of microwaves from the heating chamber, and an air baffle means is provided strategically in the hot air discharging section to ensure a uniform distribution of temperature within the heating chamber. The invention also includes an improved relative position of the air inlets, a double-deck tray and the air baffle means which functions to prevent a substantive dehydration of food which is a drawback of a conventional hot air circulation heating system.

Cooking appliance of the hot air circulating type

A cooking device with one cooking or heating chamber in which food may be heated by either one or both of high-frequency heating means and the resistance heating means. The high-frequency or microwave energy is radiated into the heating chamber from the top while the air heated to high temperatures by the resistance heating means disposed within a rear chamber defined back of the rear wall of the heating chamber is circulated therethrough by a circulation fan. Food charges are placed on a receptacle which in turn is placed on a turntable, whereby the food charges may be uniformly heated. The simultaneous use of both the high frequency heating means and the resistance heating means may enable a more wide variety of food to be cooked by a more wide variety of methods.

Cooking device with high-frequency heating means and resistance heating

A microwave oven is equipped with a rotary table driven by magnetic coupling. The microwave oven has a heating chamber in which at least its bottom wall or base plate is made of a non-magnetic metallic material, while its other walls are formed of metallic material other than non-magnetic metallic material, for reduction of the cost of the microwave oven. The junctions between the wall of non-magnetic metallic material and the walls of metallic material other than non-magnetic metallic material are coated with coating film to improve corrosion resistance. Furthermore, the heating chamber together with the rotary table is so arranged as to facilitate insertion and withdrawal of a container of food material into and from the heating chamber to provide a microwave oven which is clean and convenient to use.

Microwave oven

A microwave oven including a rotary table or turn table disposed on the bottom surface of a heating cavity and a rotary member associated with a driving motor through a driving mechanism and disposed adjacent to the rotary table and the bottom wall of the heating cavity for rotating the rotary table through magnetic coupling means. Should the rotary table be prevented from being rotated or locked for some reason, the magnetic coupling is released, so that damage to the driving motor and the like are advantageously prevented.

A microwave oven equipped with a rotary table or turntable includes a heating chamber whose rear wall is formed into a concave shape of semi-circular cross section approximately concentric with a rotational center of the rotary table to eliminate any idle space at corner portions in the heating chamber for providing an economical microwave oven of compact size, and also to prevent the rotary table from being locked by a large object to be heated which may be caught by the corner portions during rotation, with the simultaneous elimination of damage to an observation window due to spark discharge arising from a metallic material included in the object, and with the further improvement of uniform heating within the heating chamber.

A microwave oven providing the combination of dielectric heating by the use of microwaves and resistive heating for scorching the surface of a food. An isolation chamber for accommodating an article to be heated by a resistive heater is formed adjacent to the resistive heater provided in a heating cavity. When heating by the resistive heater is desired, the article to be heated is accommodated in the isolation chamber so that it is heated either both by dielectric heating and resistive heating or solely by resistive heating for scorching in an effective manner and at the same time minimizing the contamination of the heating cavity. In this manner, the application of the microwave oven may be widened and the usefulness of the microwave is enhanced.

A structure of a microwave oven door screen which facilitates the observation of the inside of a heating cavity and enhances the safety against the electromagnetic wave leakage and durability. A door screen of this type generally comprises a pair of transparent plates and an electromagnetic wave shielding material interposed therebetween. The present door screen uses a punched metal plate as the electromagnetic shielding material made of aluminum having a thickness of 0.1 to 0.35 mm, an aperture diameter of 1.2 mm or less and a ratio of the aperture diameter to a center-to-center distance of an aperture of 0.67 to 0.85, these parameters being chosen such that an aperture rate of more than 40% is assured and the electromagnetic wave leakage through the door screen is effectively prevented (to meet the Regulations of U.S. Department of Health, Education, and Welfare) and a strain due to continuous mechanical treatment of the punched metal plate is minimized.

Microwave oven door screen

Microwave oven is provided with an improved door screen which allows an undisturbed clean observation of the heating chamber and at the same time assures safety and durability in use. The door screen comprises an electromagnetic wave shielding means made of a metal mesh interposed between a pair of transparent plates. The metal mesh is constituted by electrically conductive woven wires having a predetermined diameter with the space between the wires also being numerically predetermined.

Microwave ovens

A microwave oven whose door screen is constructed by interposing an electromagnetic wave shielding body of a metallic plate having a plurality of through-holes formed therein or a wire screen, between a tempered glass plate and a transparent resin plate, with the tempered glass plate being placed on the side of a heating cavity while the transparent resin plate being placed outwardly, a peripheral section of the shielding body extending to electrically connect with a metal plate which, essentially, electrically connects the heating cavity with the door body, whereby observation of food in the heating cavity during cooking can be facilitated while the safety from electromagnetic wave leakage is assured.

Growing community of inventors

Yamatokoriyama, Japan

Toshio Kai