BACKGROUND OF THE INVENTION
Field of the Invention
[0001] The present invention relates to a door opening/closing apparatus for an electric
oven, and more particularly, to a door opening/closing apparatus for an electric oven,
capable of exactly indicating a door's opening/closing status of the electric oven
and safely shielding a cavity when the door is closed. Further, the present invention
relates to a door opening/closing apparatus for an electric oven, wherein the electric
oven is not operated upon inadvertent use of a user so that the electric oven may
be more safely used.
Description of the Related Art
[0002] Generally, an electric oven is an apparatus for cooking foods by heating an electric
heater with foods put in an inside of a cavity. The electric oven can perform a grill
or oven function using radiant heat of the electric heater or convectional hot blast
of a convection fan. Also, in case a magnetron is additionally provided, an electromagnetic
wave generated from the magnetron is radiated to an inside of the cavity, whereby
food cooking may be swiftly performed even more.
[0003] Generally, a door is formed on a front side of the electric oven and a door's opening/closing
operation in an up/down direction is performed by a hinge provided to a lower portion
of the door. A latch is formed on an upper portion of the door and inserted into and
hooked at a latch receiving hole provided to a front side of a main machine of the
electric oven, so that a closed state of the door can be stably maintained. When a
user intends to open the door, the latch is released by a predetermined mechanism
so that a user can open the door. Further, it is known that a predetermined door switch
for detecting that the latch is inserted into the latch receiving hole is provided,
so that if the latch is inserted into the latch receiving hole, the door is judged
to have been closed' and the electric oven starts to operate and if the latch is not
inserted, the electric oven does not operate even if a start button is pressed.
[0004] In the meantime, there are following problems in using the above-described general
electric oven of the related art. When temperature in an inside of the cavity reaches
a high temperature and a user who dose not yet recognize the high temperature opens
the door, there is a danger of getting burned. To prevent such a danger, another related
art of United States Patent No. 6,315,336 entitled "motorized self-cleaning oven latch"
has been suggested. However, the above US patent is difficult to realize and the manufacturing
cost is raised due to its complicated structure.
[0005] Further, even a case that a careless user inadvertently inserts a long rod into the
latch receiving hole, the related art electric oven may detect the case as a door-closed
state. In that case, the electric oven may operate unexpectedly and the user may get
burned. Still further, if the case described above occurs when the oven is overheated,
there is a dander that a fire may break out.
SUMMARY OF THE INVENTION
[0006] Accordingly, the present invention is directed to a door opening/closing apparatus
for an electric oven that substantially obviates one or more problems due to limitations
and disadvantages of the related art.
[0007] An object of the present invention is to provide a door opening/closing apparatus
for an electric oven, in which operational accidents can be prevented.
[0008] Also, an object of the present invention is to provide a door opening/closing apparatus
for an electric oven, capable of promoting a user's convenience by realizing the door
opening/closing apparatus in a more reliable manner.
[0009] Further, an object of the present invention is to provide a door opening/closing
apparatus for an electric oven, capable of reducing a damage on a user's body that
may generated due to an inadvertent use, or a danger of a fire that may be broken
out in a room due to a high temperature generated from the electric oven.
[0010] Further, an object of the present invention is to provide a door opening/closing
apparatus for an electric oven, capable of reducing manufacturing costs and enhancing
convenience in product application even more by simplifying a structure of the door
opening/closing apparatus of the electric oven.
[0011] Additional advantages, objects, and features of the invention will be set forth in
part in the description which follows and in part will become apparent to those having
ordinary skill in the art upon examination of the following or may be learned from
practice of the invention. The objectives and other advantages of the invention may
be realized and attained by the structure particularly pointed out in the written
description and claims hereof as well as the appended drawings.
[0012] To achieve these objects and other advantages and in accordance with the purpose
of the invention, as embodied and broadly described herein, a door opening/closing
apparatus for an electric oven having a cavity where a high temperature condition
is formed, a door for selectively opening/closing the cavity, and a door opening/closing
structure for exactly opening/closing the door, the door opening/closing structure
includes: a hooked portion formed on an inner side of the door; a hook selectively
caught on the hooked portion; a cam guide formed on a body of the hook; and a cam
for moving the cam guide and being rotated by external force.
[0013] According to the present invention, operational safety of the electric oven where
high temperature is generated can be enhanced even more. Further, the door opening/closing
apparatus is more reliably realized, so that user's convenience of the electric oven
can be promoted even more.
[0014] Particularly, according to the present invention, damage on a user's body due to
an inadvertent use, or a danger of a fire can be reduced.
[0015] Further, a structure of the door opening/closing apparatus of the electric oven is
simplified, whereby manufacturing cost is reduced and convenience is increased upon
application of the electric oven.
[0016] It is to be understood that both the foregoing general description and the following
detailed description of the present invention are exemplary and explanatory and are
intended to provide further explanation of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The accompanying drawings, which are included to provide a further understanding
of the invention and are incorporated in and constitute a part of this application,
illustrate embodiment(s) of the invention and together with the description serve
to explain the principle of the invention. In the drawings:
[0018] Fig. 1 is a perspective view of an electric oven to which the present invention is
applied;
[0019] Fig. 2 is a cross-sectional view, taken along line I-I' of Fig. 1, and illustrating
a construction of a latch;
[0020] Fig. 3 is a cross-sectional view, taken along line II-II' of Fig. 1;
[0021] Fig. 4 is a view illustrating a state before a latch is not inserted in a second
door opening/closing structure;
[0022] Fig. 5 is a view illustrating a state in which a latch is inserted to some extent
and a first micro-switch is switched on;
[0023] Fig. 6 is a view illustrating a state in which a latch is inserted completely and
both a first and a second micro-switches are switched on;
[0024] Figs. 7 and 8 are views illustrating that an alien material is inserted into the
second door opening/closing structure;
[0025] Fig. 9 is a cross-sectional view, taken along line III-III' of Fig. 1;
[0026] Fig. 10 is a side view of a first door opening/closing structure; and
[0027] Figs. 11 through 13 are views sequentially illustrating a movement procedure of a
hook in the first door opening/closing structure.
DETAILED DESCRIPTION OF THE INVENTION
[0028] Reference will now be made in detail to the preferred embodiments of the present
invention, examples of which are illustrated in the accompanying drawings.
[0029] Fig. 1 is a perspective view of an electric oven to which the present invention is
applied.
[0030] Referring to Fig. 1, an electric oven 1 according to the present invention includes:
a cavity 3 having a heating element in its inside; a door 30 formed on one side of
the cavity 3, for selectively being opened/closed so that food may be put in and out;
a pair of latches 20 provided to an inner side of the door 30; and a receiving hole
6 provided to one side of a housing 5, for fixing the door 30 by receiving the latch
20. Further, a hooked portion such as ring 65 formed on about a central portion of
the inner side of the door 30, and a hook 60 for selectively being engaged with the
hooked portion 65 in its inside and catching the hooked portion 65 so that the door
30 may not be opened when the door 30 is in a closed state.
[0031] Operation of the door opening/closing apparatus according to the present invention
will be briefly described below. If a user closes the cavity 3 by taking the door
30 with one hand, the latch 20 is inserted into the receiving hole 6 and fixed by
a predetermined second door opening/closing structure formed in the receiving hole
6. When the latch 20 is inserted into the receiving hole 6, the second door opening/closing
structure detects insertion of the latch 20, thereby checking detection of the door
30. Further, the second door opening/closing structure performs a function of determining
that the door is not closed when an alien material, not the latch 20, is inserted.
[0032] Further, to prevent unexpected dangerous circumstances such as a case in which the
cavity is heated to a high temperature during operation of the electric oven and a
user does not recognize such a high temperature and opens the cavity, a first door
opening/closing structure making the hooked portion 65 caught on the hook 60 is provided.
The first door opening/closing structure may be formed at an electric equipment unit
in an upper portion of the cavity.
[0033] The first door opening/closing structure can be understood as a door locking apparatus
and the second door opening/closing structure can be understood as a door interlocking
apparatus. More specifically, the door interlocking apparatus is a predetermined structure
for preventing the door from being detected as being closed using a door switch formed
in an inside of the receiving hole 6 when a user inadvertently inserts a rod into
the receiving hole 6. If the door is detected as being closed due to the inadvertently
inserted rod and the electric oven starts to operate, a dangerous circumstance such
as a fire in a room may be caused. Therefore, the door should be exactly detected
as being closed only when the latch 20 is inserted reasonably.
[0034] In the meantime, the electric oven 1 of the present invention further includes: an
operation unit 4 for operating the electric oven 1 according to a user's intention;
an exhaust port 2 for exhausting water vapor generated while food is being cooked
in an inside of the cavity 3; a convection fan 7 formed in an inside of the cavity
3, for circulating an air in the inside of the cavity 3 convectively. Further, if
necessary, a hot plate (not shown) is provided to an upper surface of the electric
oven so that a cookware such as a pot may be placed and food is cooked.
[0035] Figs. 2 through 8 are views illustrating a door interlocking apparatus according
the present invention. Referring to Figs. 2 through 8, the door interlocking apparatus
will be described in detail.
[0036] Fig. 2 is a cross-sectional view, taken along line I-I' of Fig. 1, and illustrating
a construction of a latch. Referring to Fig. 2, the latch 20 is formed in an inside
of the door 30 and the latch 20 can stably operate at a set position. For maintaining
stable operation of the latch 20, there are provided a latch pivot 21 functioning
as a pivot of the latch 20 at a central position of a latch operation, and a latch
spring 22 connecting a rear end of the latch 20 with a latch fixing part 23 to operate
the latch 20 elastically. The latch 20 slightly rotates in a clockwise direction about
the latch pivot 21 during a closing operation of the door 30 and once the latch 20
is inserted, the latch 20 rotates again in a counterclockwise direction. At this point,
since force by which the latch 20 would rotate counterclockwise is constantly applied
by the latch spring 22, a position of the latch 20 may be stably maintained. Further,
a hook-shaped latch head 24 is formed on a front end of the latch 20, thus an insertion
operation of the latch 20 can be stably performed and after the latch 20 is inserted,
a hooking operation is performed and a position of the door 30 can be fixed.
[0037] Fig. 3 is a cross-sectional view, taken along line II-II' of Fig. 1 and illustrating
a second door opening/closing structure. Referring to Fig. 3, a latch board 40 is
formed in an inside of the receiving hole 6. The latch board 40 performs a function
of detecting whether the latch 20 is inserted or not, together with a function of
fixing a position of the latch 20. Further, if an alien material such as a pin, not
the latch 20, is inserted, the latch board 40 may perform a function of detecting
that the door is not closed.
[0038] The latch board 40 includes: a plurality of operation parts 45, 48, and 50 to be
moved by the latch head 24 when the latch 20 is inserted into an inside of the receiving
hole 6; micro-switches 41 and 42 for detecting the insertion of the latch 20 by receiving
movements of the operation parts; and a latch hooking part 53 for guiding the insertion
operation of the latch 20 and fixing a position of the inserted latch 20.
[0039] More specifically, the operation parts includes: a first operation part 45 to be
touched first when the latch 20 is inserted; a third operation part 50 pressed in
cooperation with the first operation part 45; and a second operation part 48 sequentially
moving after the first operation part 45 is moved. Further, the first operation part
45, which is a plate-shaped member, rotates on a first pivot 46, and a pressing part
51 is extended from a predetermined position of the first operation part 45. The second
operation part 48 has one end touched to the latch head 24 and other end touched to
a second switch button 44 of the second micro-switch 42 so as to be rotated about
the second pivot 49. In the third operation part 50, one end is fixed to the first
micro-switch 41 and other end is pressed by the pressing part 51 so as to make a first
switch button 43 switched on. The operation parts are formed into a plate shapes,
whereby cooperative operation of the operation parts can be swiftly performed.
[0040] Further, a spring 47 is interposed between other end of the first operation part
45 and the latch board 40. A position of the first operation part 45 can be supported
by the spring 47. For example, if the latch 20 is not inserted, the first operation
part 45 is set to rotate counterclockwise on the first pivot 46. Of course, since
the first operation part 45 is rotated counterclockwise, the pressing part 51 and
the third operation part 50 are not touched each other, thus the first micro-switch
41 is in an off-state. Further, under a state that the first operation part 45 is
rotated counterclockwise, a terminal of the pressing part 51 pushes the second operation
part 48 so that the second operation part 48 may be rotated counterclockwise. Thus,
the second micro-switch 42 is also in an off-state.
[0041] If the latch 20 is inserted under such a state, the first operation part 45 and the
second operation part 48 are sequentially touched to the latch head 24. The first
operation part 45 continuously moves the third operation part 50. After that; the
first micro-switch 41 is switched on by the third operation part 50, and the second
micro-switch 42 is switched on by the second operation part 48. The micro-switches
41 and 42 are sequentially switched on, whereby the door 30 can be detected as being
normally closed. Of course, switch-on operations of the micro-switches 41 and 42 are
delivered to a controller of the electric oven, and an interval of the delivered continuous
detection signal is judged, so that the door 30 is detected as being closed. If an
alien material such as a spoon is inserted into the receiving hole 6, the operation
parts 45 and 48 are not operated continuously. In that case, it may be judged that
the door 30 is not closed because other material, not the latch 20 is inserted.
[0042] Figs. 4 through 6 are views sequentially illustrating an insertion process of the
latch. Fig. 4 illustrates a state just before the latch is inserted, Fig. 5 illustrates
a state that the latch is inserted to some extent and the first micro-switch 41 is
switched on, and Fig. 6 illustrates a state that the latch is inserted completely
and the second micro-switch 42 is also switched on as well as the first micro-switch
41.
[0043] Referring to Fig. 4, before the latch 20 is inserted, the first operation part 45
is rotated counterclockwise by the spring 47 and the pressing part 51 only touches
to the third operation part 50, thereby not applying any force on the third operation
part 50. At this point, the first and the second micro-switches 41 and 42 are all
in a switch-off state. Referring to Fig. 5, the latch head 24 is touched to the first
operation part 45, and the first operation part 45 is rotated clockwise on the first
pivot 46. If the first operation part 45 is rotated, the pressing part 51 is rotated
clockwise on the whole, pressing the third operation part 50. Then, the third operation
part 50 presses the first switch button 43 so that the first micro-switch 41 may be
switched on. Referring to Fig. 6, if inserted even further, the latch 24 pushes the
second operation part 48 to rotate the same clockwise. At this point, a terminal of
the second operation part 48 presses the second switch button 44 so that the first
micro-switch 42 may be switched on. Further, if the latch 20 is inserted completely,
the latch head 24 is hooked on the latch hooking part 53, so that the latch 20 can
be detached only when predetermined external force is applied. Thus, a position of
the closed door 30 can be stably fixed.
[0044] In the meantime, the micro-switches 41 and 42 are sequentially switched on during
a series of operations of the operation parts 45, 48, and 50. According to an experiment,
a time difference of about 4ms is generated. The continuous detection signal of the
micro-switch is delivered to the controller of the electric oven so that whether the
door is normally closed can be detected. Of course, since a continuous delivery of
the detection signal may have an error to some extent, a time difference of 4±1 ms
may be judged as closing of the door.
[0045] The sequentially operation of the micro-switch by an interlocking apparatus of the
second door opening/closing structure is intended to prevent a circuit for a safety
apparatus provided to an inside of the micro-switch from being connected simultaneously.
If the circuit for the safety apparatus operating in cooperation with the micro-switch
is connected simultaneously to operate, a power switch is falsely operated, so that
an arcing region, in which the electric oven automatically operates without an instruction
of a user, may be generated.
[0046] In the meantime, in an opening operation of the door, a hooking position of the latch
hooking part 53 and the latch head 24 is released, and the latch head 24 is rotated
clockwise by a predetermined amount in order to be ejected through the receiving hole
6. At this point, the first operation part 45 is rotated counterclockwise by force
of the spring 47, the second operation part 48 is also rotated counterclockwise by
a pressing operation of the pressing part 51, and the third operation part 50 is restored
to its original position by elasticity of its own.
[0047] Figs. 7 and 8 illustrate an operation sequence of the second door opening/closing
structure when a pin, not the latch is inserted into the second door opening/closing
structure. Referring to Figs. 7 and 8, if an alien material such as a pin P is mistakenly
inserted into the receiving hole 6 by a user, the first micro-switch 41 may be normally
switched on by the first operation part 45. However, it is easily expected that the
pin P requires a little more time to operate the second operation part 48 than the
latch 20 because it may take a more time until the first operation part 45 is pushed
to its end by the pin P to push the second operation part 48, and such a time may
be at least more than 4ms. Further, the second operation part 48 might not be pushed
by the pin P, depending on cases.
[0048] Since closing of the door can be exactly detected by the above-described second door
opening/closing structure, malfunction associated with the door is reduced.
[0049] Figs. 9 through 13 illustrate the first door opening/closing structure as a door
locking apparatus. The first door opening/closing structure is intended to prevent
the door from being opened even by an external force from a user while a thermal decomposition
cleaning is performed in the cavity, so that user's safety can be enhanced even more.
[0050] Fig. 9 is a cross-sectional view taken along line III-III' of Fig. 1, illustrating
the first door opening/closing structure. Referring to Fig. 9, the first door opening/closing
structure includes: a hook 60 selectively hooked on the hooked portion 65; and a hook
operation unit 80 for generating external force by which the hook 60 is operated.
The hook operation unit 80 includes: a motor 70 for generating power; a cam operation
shaft 71 extended to a lower side of the motor 70 so that the hook 60 may be operated
in cooperation with the motor 70; a cam 72 on an eccentric position of which the cam
operation shaft 71 is formed; and a cam guide 73 into which the cam 72 is inserted
so that a predetermined hook operation is performed. Further, a guide slot 61 having
an elongated shape in an up and down direction is formed on each side of the cam guide
73, and a guide member 82 fixed to the hook operation unit 80 is provided in the guide
slot 61 to guide a movement of the hook 60, are provided. Further, a micro-switch
81 performing on/off operation according to a rotational angle of the cam 72 is provided
to control closing/releasing of the door.
[0051] In the meantime, the guide slot 61 is formed obliquely a predetermined angle of α
so that the hook 60 may move in a direction inclined a predetermined angel.
[0052] Fig. 10 is a side view of the first door opening/closing structure. Referring to
Fig. 10, the motor 70, the cam operation shaft 71 extending downwardly from the motor
70, the cam 72 formed at the end of the cam operation shaft 71, and the micro-switch
81 are illustrated.
[0053] Referring to the above-described first door opening/closing structure, an operation
of the first door opening/closing structure will be briefly described. When the motor
70 is rotated, the cam operation shaft 71 is rotated. The cam operation shaft 71 rotates
the cam 72 on the whole and the cam 72 pushes the cam guide 73 so that the hook 60
may be moved wholly in up and down directions. Further, when the hook 60 is moved
in the up and down directions, the hook 60 is made to be moved in a predetermined
direction only by interaction between the guide slot 61 and the guide member 82, whereby
the hook 60 can be exactly hooked on the hooked portion 65. Further, it is also possible
to make the rotation of the motor 70 stopped when the rotation of the cam operation
shaft 71 is detected by the micro-switch 81, and the door may be judged to have been
closed completely.
[0054] Figs. 11 through 13 sequentially illustrate a movement process of the hook. Referring
to Figs. 11 through 13, the hooked portion 65, the cam 72, the cam operation shaft
71, and the guide member 82 are fixed and only the hook 60 is moved.
[0055] Referring to Fig. 11, the hook 60 is hooked on the hooked portion 65 so that the
door 30 is closed. Under such a state, even if a user intends to open the door, the
door would not be opened. The inside of the cavity may be in a state in which food's
remnant is being thermally decomposed by high temperature. The cam operation shaft
71 is rotated, such that the cam 72 is rotated about the cam operation shaft 71. The
cam operation shaft 71 forces the hook 60 to move on the whole by an operation of
pushing/pulling the cam guide 73. The hook 60 is moved in a predetermined direction
by an interaction between the guide member 82 and the guide slot 61. Particularly,
since the guide slot 61 is obliquely formed from the upper left to the lower right,
the hook 60 is also moved in the direction inclined toward the upper left in order
to be completely detached from the hooked portion 65.
[0056] Fig. 12 illustrates that the hook 60 has moved half of the whole movement distance
with the cam rotated about 90°, and Fig. 13 illustrates that the hook 60 has moved
completely the whole movement distance with the cam rotated about 180°.
[0057] Further, although Figs. 11 through 13 illustrate that the hook is moved to a door-opening
direction, it is easily expected that the hook will be moved in a door-closing direction
by movement of the cam 72 in an opposite direction.
[0058] In the meantime, although the present embodiment explains that the hooked portion
is formed in the door and the hook is formed in the main machine of the oven, the
hook and the hooked portion may be also formed in the door and the main machine, respectively,
of course. The above configuration may be applied in the same way to the second door
opening/closing structure.
[0059] In the door opening/closing apparatus of the electric oven according to the present
invention, the first door opening/closing structure, a door locking structure, prevents
the locked door from opening, and simultaneously the second door opening/closing structure,
a door interlocking structure, indicates the opening/closing of the door exactly.
Thanks to such a configuration, the first door opening/closing structure is operated
only when the door is detected as being completely closed by the second door opening/closing
structure. However, either the first or the second opening/closing structure may be
selectively applied, depending on a specific application type of the electric oven.
That is, by mounting the first door opening/closing structure, it is possible to safely
use the electric oven when the door is closed. By mounting the second door opening/closing
structure, it is also possible to prevent the electric oven from being operated under
an unsafe state resulting from an inadvertent behavior of a user. Of course, the whole
sprit of the present invention can be fully realized in case both the first and the
second opening/closing structures are used simultaneously.
[0060] Further, although the first and the second opening/closing structures perform their
opening/closing operation using the latch and the hooked portion separately formed
in the door, the first and the second opening/closing structures may also operate
in cooperation with each other using a latch structure integrally formed in the door.
[0061] According to the door opening/closing apparatus of the present invention, an accident
that may occur due to malfunction of the electric oven can be prevented in advance,
and thereby a safety in using the electric oven can be enhanced even more.
[0062] Particularly, since opening of the door is prevented in case the inside of the cavity
is maintained at high temperature due to an inadvertent use, safety in using the electric
oven is enhanced even more. Further, an erroneous detecting that the door is closed
due to insertion of an alien material can be prevented, whereby a danger of a fire
in a room due to a high temperature generated from the electric oven can be removed.
[0063] Still further, the structure of the door opening/closing apparatus of the electric
oven is simplified, so that manufacturing cost can be reduced and the apparatus can
be conveniently applied to products.
[0064] It will be apparent to those skilled in the art that various modifications and variations
can be made in the present invention. Thus, it is intended that the present invention
covers the modifications and variations of this invention provided they come within
the scope of the appended claims and their equivalents.