Note: Descriptions are shown in the official language in which they were submitted.
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The present invention xelates to a combination micro-
wave and electric oven and~ more particularly, to such an oven
includ~n~ a turntable.
~ combination microwave and electric oven has been
developed as disclosed in U.S. Patent No. 3,172,98~ entitled
"COMBINATION EIJECTRIC AND ELECTRONIC OVENS " on March 9, 1965 . A
turn~able is provided to faci~itats uniform microwave cooking,
and a heater mean~ is disposed below the turntable to maintain
the oven temperature at a predetermined value in the electric
heating mode. ` -
In the conventional combination microwave and electric
oven, a~heater means is disposed between a stainless steel turn-
table and a bottom wall of an oven cavity. The conventional
combinatlon microwave and electric oven such as disclosed in the
above~mentioned U.S. Patent NO. 3,172,987 is very large and,
therefore, a suf~icient space is provided between the stainless
steel turntable and the heater means~
However! when a compact si~e combination microwave and
electric oven is desired to be fabricated, the distance between
the twrntable and the heater means is unavoidably reduced. When
~ the turntable is made of stainless steel, uniform cooking can not
-~ be achieved in the electric cooking mode, because the stainless
steel turntable does not have a uniform surface temperature when
~he heater means is close to the turntable.
Moreovar, there is a possibility of sparks being gener-
ated by the stainless steel t~rntable when microwaves of a high
frequency, ~or example, 2450MHZ, are introduced into the oven
cavity~
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Accord,ing to the present invention there is provided
a combination microwave and electric oven comprising an oven
cavity, microwave generation means for microwave cooking pur-
poses, a turntable disposed in a lower seclion of the oven
cavity, and a heater means disposed be~ween the turntable and a
bottom wall of the oven cavity for electric cooking purposes,
wherein the turntable is a metallic turntable coated with
heat resistant non-metallic material to prevent the occurence
of sparks when the turntable is rotated during microwave cooking
operations and to ensure the even distribution of heat within
the turntable during electric cooking operation.
According to the present invention, there is also
provided a turntable for use in a combination microwave and
electric oven including an oven cavity, microwave generation
means for microwave cooking purposes and a heater means disposed
between the turntable and a bottom wall of the oven cavity
for electric cooking purposes, the turntable being disposed
in a lower section of the oven cavity and comprising: a metal
,;
body of a high thermal conductivity for reflecting microwaves ~ '-
and transmitting heat energy; and a heat resistant non-metallic
materlal layer formed on the metal body for preventing an
occurrence of sparks during microwave cooking and for uniformly
distributing the heat energy when the heater means is energi~ed.
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Such an oven can be of a compact size and yet can
achieve stable and uniform cooking in both microwave cooking and
elactric heating cooking modes.
The heat resistant non-metallic coating on the metal
turntable, which may be an enamel, functions to render more
uniform the surface temperature of the turntable in the electric
heating cooking mode, and to prevent the occurrence of sparks in
the microwave cooking mode. In a preferred form, openings are
formed in the turntable to stlr the microwave energy in the
microwave cooking mode during rotation of the turntable.
The present invention will be more fully understood
from the detailed description given below by way of example of
preferred embodiments thereoE and with reference to the accom- ~ ;
panying drawings, which are given by way of illustration only
and are not limita~ive of the present inven-tion, in which:
Figure 1 is a sectional view of a combination micro-
wave and electric oven including an embodiment of an enameled
metal turntable;
Figure 2 is a sectional view of the enameled metal
turntable employed within the oven of Figure l;
Figure 3 is a plan view showing the enameled metal
turntable of Figure 2 and showing in dotted lines a coupler
for driving the turntable;
Figure 4 is a perspective view of the coupler shown
in Figure 3;
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Figure 5 is a plan view oE another embodiment of an
enameled metal turn-table;
Figure 6 is a sectional view of the enameled turn-table
as seen at VI-VI o~ Figure 5.
Figure 1 shows a combination mi.crowave and electric
oven 10 which mainly comprises an oven wall 12 defining an oven
cavity, an enameled metal turntable 14 for supportin~ a foods-tuff
mounted thereon, and a sheath heater 16 disposed between the
turntable 14 and the bottom wall o~ the oven cavity in a ~ashion
-to surround a coupler 30 described below.
An upper heater unit 18 compri.ses a sheath heater 180
and a reflec-tion plate 182. The upper heater unit 18 and -the
sheath heater ].6 function, in combination, to heat the oven in an
electric heating cooking mode. A hea-t insulating wall or an
athermanous wall 20 made of, for example, glass wool, asbestos
or calcium silicate is provided in such a manner as to surround ;'
the oven wall 12, whereby -the oven cavity is readily maintained
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: at a high temperature in the electric heating cooking mode.
l~icrowave energy genera-ted from a magnetron 22 is intro-
~; 20 duced into the oven cavity through a waveguide 24 for performing
; microwave cooking~ A power supply unit 25 is disposed outside
the oven cavity.
, The enameled metal turntable 14 is driven to rotate in :~
both the microwave cooking mode and the electric hea-ting cooking
mode through the use of a turntable motor 26, a drive mechanism
~! 28, and the coupler 30.
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Figure 2 shows a sectional view of the enameled metal
-turntable 14, which mainly comprises a steel plate 140 coated -~
with enamel 142. Coupling projec-tions 144 are formed on -the bottom
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surface of the enameled metal tuxntable 14. I'he enameled metal
turntable 14 is removably engaged with the coupler 30 through
the use of the coupling projections 144. The thickness of the
enamel 1~2 is preferably in the range from 0.1 through O.5 mm.
Figure 3 shows the enameled metal turntable 14 engaged
with the coupler 30. Like elements corresponding to those of
Figures 1 and 2 are indicated by like numerals.
The enameled metal turntable 14 i9 driven to rotate
about the center thereo~, and supportiny roll~rs 3~ are rotatably
fixed to the bottom wall of the oven cavity at desired positions
to ensure stable rotation of the enameled metal turntable 14.
- Figure 4 show~ the coupler 30, which is made of heat-
resisting plastics and has projections 3QO which are engaged with
the coupling pro~ections 144 for rotating the enameled metal
~-~ turntable 14.
-~ Figures 5 and 6 show another embodiment of the enameled
metal turntable. Like elements corresponding to those of Figures
2 through 4 are indicated by like numerals. As shown in Figures
5 and 6, openings 146 are fo~med in the enameled metal turntable
~ ~0 14 ~or stirring the microwaves introduced into the oven cavity
during the microwave cooking modes as enameled metal turntable
14 rotates.
The invention being thus described, it will be obvious
to those skilled in the art that the same may be varied in many
ways. Such variations are not to be regarded as a departure
from the spirit and scope of the invention, and all such modifi-
cations are intended to be included within the scope of the
following claims.
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