Electric heating – Microwave heating – Radiation protection
Reexamination Certificate
2002-12-20
2004-07-06
Leung, Philip H. (Department: 3742)
Electric heating
Microwave heating
Radiation protection
C219S740000, C219S756000, C124S035100
Reexamination Certificate
active
06759638
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a microwave oven, and more particularly, to a microwave oven having a door which is projected forward to allow a user to observe a cooking chamber from various locations and constructed to be easily manufactured.
2. Description of the Related Art
Generally, a microwave oven is an appliance that cooks or heats food laid in a cooking chamber using microwaves that are generated by a magnetron disposed in a machine room. The microwave oven cooks or heats the food using a frictional heat produced between moisture molecules of the food, and generated by irradiating the microwaves into the cooking chamber. That is, the microwaves repeatedly change the molecular arrangement of moisture contained in the food to cook the food.
FIG. 1
shows a perspective view of a conventional microwave oven with its door
8
opened. As shown in
FIG. 1
, the microwave oven comprises a housing
1
having a machine room
2
and a cooking chamber
3
partitioned from each other in an interior of the housing
1
. A magnetron
4
which generates microwaves, and a blower fan
5
which cools the magnetron
4
and discharges moisture and odor generated from food to the outside of the microwave oven are mounted in the machine room
2
. The blower fan
5
discharges the moisture and odor by circulating air through the cooking chamber
3
.
The cooking chamber
3
is constructed in a form of a box with its front opened. The cooking chamber
3
has a rectangular bottom
3
a
, a front end of which is laid on the same plane as a front of the cooking chamber
3
. A turntable
6
which allows the food to be laid thereon, and a rotation guide (not shown) which rotatably supports the turntable
6
are mounted on the rectangular bottom
3
a
. The turntable
6
is rotated at a relatively low speed while being coupled to a motor (not shown) disposed under the cooking chamber
3
.
The door
8
is rotatably hinged to one side of the housing
1
in front of the cooking chamber
3
so as to selectively open and close the cooking chamber
3
. The door
8
is constructed in a form of a rectangle. A see-through member
9
having a plurality of see-through holes is fitted into a center portion of the door
8
to allow a user to see through the door
8
. The door
8
, including the see-through member
9
, has planar front and back surfaces. Accordingly, where the door
8
is tightly closed, the planar back surface of the door
8
comes into close contact with the front of the cooking chamber
3
, and the front of the door
8
constitutes a plane.
Where the microwave oven operates, the microwaves generated by the magnetron
4
are irradiated into the cooking chamber
3
, and simultaneously, the turntable
6
is rotated at a relatively low speed. Accordingly, the food laid on the turntable
6
is cooked by the irradiated microwaves.
However, since the conventional microwave oven having the construction as described above is shaped in a form of a hexahedron and the see-through member
9
formed to allow a user to see through the door
8
constitutes a plane along with the frame of the door
8
, the user has to observe the interior of the cooking chamber
3
with his eyes being level with the see-through member
9
. That is, the user must adjust his/her body toward and directly in front of the see-through member
9
to ascertain a cooking status of the food.
Specifically, the door
8
of the conventional microwave oven and the see-through member
9
thereof are planar, and a region where the see-through holes are formed is small as compared to the overall size of the door
8
. Therefore, the user has to approach the see-thorough member
9
to observe the interior of the cooking chamber
3
. As a result, the conventional microwave oven is inconvenient and time-consuming for the user to ascertain the cooking status of the food being cooked in the cooking chamber
3
. Therefore, the user cannot carry out other tasks and must remain attentive to the microwave oven while cooking the food with the conventional microwave oven.
SUMMARY OF THE INVENTION
Accordingly, it is an aspect of the present invention to provide a microwave oven which allows a cooking status of food being cooked in a cooking chamber to be easily and rapidly ascertained from various locations.
Another aspect of the present invention is to provide a microwave oven having a door which enables a user to observe the interior of a cooking chamber from various locations, and is constructed to be easily manufactured.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
To achieve the above and/or other aspects of the present invention, there is provided a microwave oven comprising a heating unit to cook food, a cooking chamber having an opening, and a door which selectively opens and closes the opening of the cooking chamber. The door comprises a first piece including a frame which is constructed to form an outer edge of the door and be brought into contact with a rim of the opening, and a second piece including a front plate which is projected forward from both sides of the frame, wherein the door is formed by joining the first piece with the second piece.
The first piece may further include top and bottom plates, and the top and bottom plates are attached to respective upper and lower ends of the front plate to form a cooking space extending from the cooking chamber, together with the front plate.
The front, top and bottom plates may be made of metallic plates, and the front and top plates-include a plurality of see-through holes.
The heating unit may include a magnetron which generates microwaves to cook the food, and the frame may include a plurality of choke slits which prevent a leakage of the microwaves from the cooking chamber through the door, where the opening is closed by the door.
The front plate may have a half-cylinder shape, and the top and bottom plates may each be shaped in a form of a semi-circle to cover a top and a bottom of an inner space formed inside the front plate, respectively.
The front plate may have a half-box shape with an open top and bottom, and the top and bottom plates may each be shaped in a form of a rectangle to cover a top and a bottom of an inner space formed inside the front plate, respectively.
The top and bottom plates may be attached to the respective upper and lower ends of the front plate through one of a welding process, a caulking process and a riveting process.
The front plate may include flange portions which extend outward from respective side ends of the front plate, and the flange portions are attached to corresponding inner ends of the both sides of the frame constituting the first piece.
The flange portions may be attached to the frame through one of a welding process, a caulking process and a riveting process.
The frame may include stepped portions which are provided at the inner ends of the both sides of the frame so as to receive the flange portions of the front plate.
In the microwave oven of the present invention, the first piece may be manufactured by primarily manufacturing a single flat body, into which the frame and the top and bottom plates are integrated, through a press working process, and secondarily bending the top and bottom plates forward at a right angle.
REFERENCES:
patent: 3594531 (1971-07-01), Hough
patent: 3943318 (1976-03-01), Hirai
patent: 4645892 (1987-02-01), Gustafsson
patent: 4794218 (1988-12-01), Nakano et al.
patent: 5365918 (1994-11-01), Smith et al.
patent: 1-184332 (1989-07-01), None
U.S. patent application Ser. No. 10/323,739, Dae-Sung Han et al., filed Dec. 20, 2002.
U.S. patent application Ser. No. 10/324,057, Dae-Sung Han et al., filed Dec. 20, 2002.
Han Dae-Sung
Han Yong-Woon
Jang Seong-Deog
Kang Han-Seong
Yeo Joo-Yong
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