Electric heating – Microwave heating – With control system
Reexamination Certificate
2000-11-20
2001-10-09
Leung, Philip H. (Department: 3742)
Electric heating
Microwave heating
With control system
C219S723000, C219S702000, C219S715000, C219S756000, C200S050010
Reexamination Certificate
active
06300610
ABSTRACT:
CLAIM OF PRIORITY
This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. §0119 from my application MICROWAVE OVEN filed with the Korean Industrial Property Office on Aug. 25, 2000 and there duly assigned Serial No. 49442/2000.
1. Technical Field
This invention relates in general to microwave ovens, and more particularly, to a microwave oven with a configuration simplified by decreasing the number of necessary components.
2. Description of the Related Art
FIG. 4
is an exploded perspective view partially showing a conventional microwave oven, and
FIG. 5
is a detailed circuit diagram specifically showing a conventional door safety device. Referring to these figures, a conventional microwave oven is comprised of a main casing
101
having a cooking chamber
103
and an electronic component chamber
105
, a door
107
for opening and closing a front part of the cooking chamber
103
, and a control panel
109
provided in the main casing
101
, for operating a number of components in the microwave oven. In the component chamber
105
are provided a high-voltage transformer
131
generating a high-voltage based on an electric power supplied from a power supply part
130
, and a magnetron
133
generating electromagnetic waves based on the high-voltage generated by the high-voltage transformer
131
.
The microwave oven
107
is equipped with a safety device to prevent the electromagnetic waves from being supplied into the cooking chamber
103
while the door is being opened. The safety device is comprised of a latch member
113
mounted at the door
107
so as to be engaged with a pair of hook holes
111
provided in a front wall part of the cooking chamber
103
, and safety switches which are switched on and off depending upon the opening and closing of the door
107
. The latch member
113
includes a pair of hooks
115
fitted into the hook holes
111
; and the safety switches include a first door switch
145
, a second door switch
147
and a pair of monitor switches
149
.
Hereinafter, the conventional safety device for the door will be described in more detail with reference to a detailed circuit diagram shown in FIG.
5
.
The conventional microwave oven has the power supply part
130
, the high-voltage transformer
131
generating the high-voltages based on the electric power supplied from the power supply part
130
, and the magnetron
133
generating electromagnetic waves generated based on the high-voltage from the high-voltage transformer
131
. Referring to the illustrated circuit diagram, a first current line L
2
and a second current line L
3
are respectively provided on both ends of a primary coil of the high-voltage transformer
131
. A common current line L
1
is installed between the first and second current lines L
2
and L
3
, forming a closed loop by being combined with the lines L
2
and L
3
.
On the common current line L
1
are provided the power supply part
130
, and a fuse
135
for cutting off overcurrent. Between the common current line L
1
and the first current line L
2
, a lamp
137
for illuminating the inside of the cooking chamber
103
and a fan motor
139
are connected in parallel with each other. The monitor switches
149
are respectively provided between the common current line L
1
and the first current line L
2
, and the common current line L
1
and the second current line L
3
, respectively. The monitor switches
149
are closed when the door is being opened whereas they are opened when the door is closed.
With this configuration, the first door switch
145
and the second door switch
147
are opened when the door is opened, thereby cutting off the electric power supplied into the magnetron
133
. Consequently, the electromagnetic waves from the magnetron
133
cannot be generated while the door is being opened.
In the conventional microwave oven equipped with such a safety device, in order to provide a more effective safety device, it would be necessary to reduce the number of the safety switches and have a simplified configuration of the circuit. In a word, it is needed to save the cost of production and avoid the complexity of the circuits' configuration.
SUMMARY OF THE INVENTION
Therefore, the present invention has been made in view of the above needs, and it is an object of the present invention to provide a microwave oven having a configuration of circuits simplified by decreasing the number of switches.
This and other objects of the present invention may be achieved by a provision of the microwave oven comprising a main casing with a cooking chamber, a door for opening and closing the cooking chamber, and a magnetron in the main casing, for heating food within the cooking chamber, the microwave oven further comprising a power supply part; a plurality of contact parts provided to the main casing to be spaced from each other, being electrically connected to the power supply part; and a conductive part provided at the door, being electrically connected to the contact parts.
Preferably, the conductive part and the contact parts are electrically disconnected when the cooking chamber is opened, to prevent the electric power from the power supply part from being supplied into the magnetron.
More effectively, the microwave oven further comprises a latch member having a plurality of hook holes formed in a front wall part of the cooking chamber, and a plurality of hooks provided at the door, being fitted into the respective hook holes, and the conductive part is provided inside the latch member so as to be exposed from the hooks toward the contact parts.
More preferably, on the conductive part or the contact parts are provided elastic members capable of elastically deformed in a transverse direction relative to opening and closing of the door, and the elastic member are comprised of a plate spring contacting with the contact parts.
REFERENCES:
patent: 3777098 (1973-12-01), Tapper
patent: 5235150 (1993-08-01), Buske et al.
patent: 5546927 (1996-08-01), Lancelot
patent: 5746456 (1998-05-01), Violo et al.
patent: 5818015 (1998-10-01), Lee et al.
patent: 1 047 119 (1979-01-01), None
patent: 59-153032 (1984-08-01), None
Han Dae-Sung
Kang Han-sung
Bushnell Robert E.
Leung Philip H.
Samsung Electronics Co,. Ltd.
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