Electric heating – Microwave heating – With control system
Reexamination Certificate
2000-01-13
2001-12-25
Leung, Philip H. (Department: 3742)
Electric heating
Microwave heating
With control system
C219S724000, C200S050120
Reexamination Certificate
active
06333495
ABSTRACT:
CLAIM OF PRIORITY
This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. §119 from applications for DOOR INTERLOCK APPARATUS OF A MICROWAVE OVEN earlier filed in the Korean Industrial Property Office on the 14th of January 1999 and there duly assigned Ser. No. 760/1999, and for DOOR INTERLOCK APPARATUS OF A MICROWAVE Oven earlier filed in the Korean Industrial Property Office on the 14th of January 1999 and there duly assigned Ser. No. 761/1999.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a microwave oven, and more particularly to a safety device for a microwave oven which is operated in accordance with the opening/closing status of a door of the microwave oven to selectively connect a power supply with a driving circuit.
2. Description of the Prior Art
Generally, a microwave oven is a device for cooking/warming food by using microwaves, and has the advantage that it cooks various kinds of foods within a short period of time while keeping the original texture of the foods.
A conventional microwave oven is shown in FIG.
1
. Referring to
FIG. 1
, the conventional microwave oven has a cabinet
10
which is divided into a cooking chamber
10
a
and a device chamber
10
b
. The cooking chamber
10
a
receives the food to be cooked therein, and a door
30
is mounted on the front side of the cooking chamber
10
a
. Various electric components
22
a
,
22
b
,
22
c
,
22
d
are arranged in the device chamber
10
b
for generating the microwaves for cooking the desired food, and a control panel
40
is formed on the front side of the device chamber
10
b.
However, there is the possibility that the microwave oven can be operated without the door
30
being completely closed, and the microwaves radiated into the cooking chamber
10
a
may leak outside, harming the user. In order to prevent such a dangerous use, a safety device is essentially required for the microwave oven to selectively control the operation of the microwave oven by detecting the opening/closing status of the door
30
.
FIG. 2A
shows the safety device of a conventional microwave oven.
Referring to
FIG. 2A
, the safety device of the subject conventional microwave oven includes a first switch
41
, a second switch
42
, and a third switch
43
, all of which are formed on a door latch
12
of the device chamber
10
b
, and a door key
37
having a pair of key switch portions
37
a
and
37
b
formed on the door
30
for operating the contact points of the first, second, and third switches
41
,
42
, and
43
.
The first switch
41
is arranged near the end of a first guide portion
13
a
, and the second and third switches
42
and
43
are arranged near the end of a second guide portion
13
b
. Between the second guide portion
13
b
and the third switch
43
, a switch lever
44
is disposed such that it is pivoted on a hinge axis
44
a
. The first, second, and third switches
41
,
42
, and
43
selectively connect a power supply (not shown) with a driving circuit (not shown) of the microwave oven.
As the user closes the door
30
, the pair of key switch portions
37
a
and
37
b
of the door key
37
are inserted into a pair of insert holes
12
a
and
12
b
of the door latch
12
, and are guided along the guide portions
13
a
and
13
b
, respectively. Accordingly, by the second key switch portion
37
b
, the switch lever
44
is pivoted, and the contact point of the third switch
43
is operated. When the door
30
is completely closed, as shown in
FIG. 2B
, the pair of key switch portions
37
a
and
37
b
are moved downward by a spring
37
c
, so that the contact points of the first and second switches
41
and
42
are operated. Only when the contact points of the first, second, and third switches
41
,
42
, and
43
are operated, the power supply (not shown) is connected to the driving circuit (not shown).
In the event that the door
30
is incompletely closed and any contact point of the first, second, and third switches
41
,
42
, and
43
is not in operation, the power supply (not shown) can not make contact with the driving circuit (not shown), and as a result, the microwave oven can not be turned on.
According to the safety device of the subject conventional microwave oven, however, the third switch
43
, which is located in the innermost part of the device chamber
10
b
, is positioned to be operated indirectly via the switch lever
44
. Therefore, a space for the switch lever
44
between the second key switch portion
37
b
and the third switch
43
is needed, and the length L of the door latch
12
is lengthened.
As the length L of the door latch
14
is lengthened, the total available space in the device chamber
10
b
is relatively reduced, and the space for the various operational components
22
a
,
22
b
,
22
c
, and
22
d
is reduced. Accordingly, the efficient assembly of the microwave oven is deteriorated.
Further, according to the safety device of the conventional microwave oven, as shown in
FIGS. 2A and 2B
, wiring pins
41
a
and
42
a
of the first and second switches
41
and
42
are extended inward in the device chamber
10
b
, while the wiring pin
43
a
of the third switch
43
is extended toward the door
30
. Accordingly, the wiring structure becomes complex, and the assembly of the microwave oven is deteriorated due to the complex wiring process.
SUMMARY OF THE INVENTION
The present invention has been developed to overcome the above-mentioned problems of the referenced prior art, and accordingly, it is a first object of the present invention to provide a safety device for a microwave oven capable of improving the assembly of the microwave oven by reducing the space needed for a door latch and thus securing more assembly space for other component parts.
A second object of the present invention is to provide a safety device for a microwave oven which simplifies the wiring process and structure of switches, by extending the wiring pins of the switches in substantially the same direction.
The first object is accomplished by a safety device for a microwave oven including a door, a cabinet having a cooking chamber and a device chamber, a power supply, and a driving circuit according to the present invention, comprising: a door key movably mounted on the door of the microwave oven and having a key switch portion protruding toward the front side of the cabinet; and a plurality of switches turned on/off in accordance with drawing/withdrawing of the key switch portion, to selectively connect the power supply with the driving circuit, in which one of the plurality of switches, that is arranged in the innermost position of the device chamber, is operated directly by the key switch portion.
Further, the second object is accomplished by a safety deice for a microwave oven including a door, a cabinet having a cooking chamber and a device chamber, a power supply, and a driving circuit according to the present invention, comprising: a door key movably mounted on the door of the microwave oven and having a key switch portion protruding toward the front side of the cabinet; and a plurality of switches to be turned on/off in accordance with the drawing/withdrawing of the key switch portion to selectively connect the power supply with the driving circuit, in which wiring pins of the plurality of switches are extended either in a direction of the vertical line of the door key, or inward the device chamber from the vertical line of the door key.
REFERENCES:
patent: 3865097 (1975-02-01), Robinson
patent: 4982063 (1991-01-01), Tsunekawa et al.
patent: 2143410A (1985-02-01), None
patent: 2172180A (1986-09-01), None
patent: 60-245936 (1985-12-01), None
patent: 60-263036 (1985-12-01), None
patent: 61-268924 (1986-11-01), None
patent: 63-21422 (1988-01-01), None
patent: 64-70618 (1989-03-01), None
patent: 5-26451 (1993-02-01), None
patent: 5-66018 (1993-03-01), None
patent: 6-272871 (1994-09-01), None
German Patent Office Action, dated May 2, 2001 (English translation is attached.).
Bushnell , Esq. Robert E.
Leung Philip H.
Samsung Electronics Co,. Ltd.
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