U.S. patent application number 16/364620 was filed with the patent office on 2019-10-03 for latch holder having automatic opening structure and an appliance with automatic opening door using latch holder.
The applicant listed for this patent is LG ELECTRONICS INC.. Invention is credited to Seongho JEONG, Jeongkil KIM, Sangki LEE, Jangmo SHIN, Myeong Jun SHIN.
Application Number | 20190301203 16/364620 |
Document ID | / |
Family ID | 65991670 |
Filed Date | 2019-10-03 |
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United States Patent
Application |
20190301203 |
Kind Code |
A1 |
SHIN; Jangmo ; et
al. |
October 3, 2019 |
LATCH HOLDER HAVING AUTOMATIC OPENING STRUCTURE AND AN APPLIANCE
WITH AUTOMATIC OPENING DOOR USING LATCH HOLDER
Abstract
A lever pushes a latch drawn into a hook accommodating space in
a latch holder in a direction where a door opens is installed in
the latch holder, and the latch is released from the latch holder
using the lever. The door that is opened by an initial opening
angle by the latch holder releasing the latch automatically opens
by self-weight of the door.
Inventors: |
SHIN; Jangmo; (Seoul,
KR) ; KIM; Jeongkil; (Seoul, KR) ; SHIN;
Myeong Jun; (Seoul, KR) ; JEONG; Seongho;
(Seoul, KR) ; LEE; Sangki; (Seoul, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
LG ELECTRONICS INC. |
Seoul |
|
KR |
|
|
Family ID: |
65991670 |
Appl. No.: |
16/364620 |
Filed: |
March 26, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E05B 15/1635 20130101;
E05Y 2201/21 20130101; F24C 15/023 20130101; H05B 6/6417 20130101;
E05C 19/12 20130101; E05F 1/1261 20130101; E05F 3/02 20130101; E05F
3/20 20130101; E05Y 2201/254 20130101; E05F 3/18 20130101; E05B
47/0046 20130101; E05B 2047/0068 20130101; H05B 6/6414 20130101;
E05F 3/224 20130101; E05Y 2800/26 20130101; E05Y 2900/302 20130101;
F24C 15/022 20130101; E05B 15/022 20130101; E05Y 2900/308 20130101;
E05Y 2201/264 20130101; E05B 47/0012 20130101; E05F 1/1276
20130101 |
International
Class: |
E05B 47/00 20060101
E05B047/00; E05C 19/12 20060101 E05C019/12; E05B 15/02 20060101
E05B015/02; E05B 15/16 20060101 E05B015/16; F24C 15/02 20060101
F24C015/02 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 27, 2018 |
KR |
10-2018-0035257 |
Apr 2, 2018 |
KR |
10-2018-0038379 |
Apr 11, 2018 |
KR |
10-2018-0042414 |
Claims
1. An appliance, comprising: a main body having a cavity with an
open front; a door that opens and closes the open front of the
cavity; a rotational axis member that serves as a center of
rotation for opening and closing movements of the door, wherein the
rotational axis member swivably connects a bottom of the door to
the main body; a latch provided in the door that extends from a
surface of the door facing the main body and that is swivable
around a pivot axis in the door; and a latch holder in the main
body, the latch holder including: a holder body including a hook
accommodating space that holds the latch when the latch enters the
main body to keep the door closed; a lever that pushes the latch
held in the hook accommodating space of the holder body to release
the latch when the door is opened in a direction the door opens;
and a motor to drive the lever, wherein the lever pushes the latch
to open the door by a predetermined angle such that the door
continues to open by self-weight of the door.
2. The appliance of claim 1, wherein the latch is provided on both
sides of the door, the two latches swivel independently from each
other, and the lever and the motor are is provided only to one of
the latch holder.
3. The appliance of claim 1, wherein the latch includes a latch bar
that extends from the door toward the main body and a hook member
that protrudes downward from an end of the latch bar to be held by
the hook accommodating space of the holder body, the hook member
including a rear inclined surface; the door includes a spring to
apply elastic force to the latch in a direction where the hook
member moves downward; and the holder body includes a latch passage
forward the hook accommodating space, the latch passage including
an outer inclined surface and an inner inclined surface provided at
a rear of the outer inclined surface, wherein, as the door is
closes, the hook member contacts and slides along the outer
inclined surface and when the door is closed, the rear inclined
surface of the hook member catches with the inner inclined surface
while the hook member is held in the hook accommodating space of
the holder body.
4. The appliance of claim 1, wherein holder body includes a lever
supporting portion in which the lever is swivably installed, the
lever including a pushing member that contacts the hooking member
of the latch, the pushing member includes a push-up inclined
surface and a push-end part at a front end; and the hook member
includes a low distal end inclined surface, wherein, as the lever
swivels to open the door by the predetermined angle, the push-up
inclined surface of the pushing member lifts the low distal end
inclined surface of the hooking member upward and forward toward
the push-end part until the hooking member is no longer held in the
hook accommodating space of the holder body.
5. The appliance of claim 4, wherein the pushing member comprises
an inner insertion member made from a metallic material and an
outer insertion member made from a resin material.
6. The appliance of claim 4, wherein the latch passage of the
holder body includes an upper ceiling and the latch includes an
upper inclined surface provided at an upper distal end of the
latch, wherein, as the hooking member of the latch is closer to the
push-end part of the pushing member, the upper ceiling of the latch
passage is more parallel with the upper inclined surface of the
latch until the upper inclined surface of the latch contacts the
upper ceiling of the latch passage.
7. The appliance of claim 4, wherein the pushing member is disposed
further downward than a rotational center of the lever, and as the
lever is rotated, a position of the hook member contacting the
push-up inclined surface of the pushing member moves lower down the
push-up inclined surface and when the push-end part of the pushing
member is a same height as the rotational center of the lever, the
lever has pushed the hook member farthest away from the pushing
member.
8. The appliance of claim 4, wherein the lever includes an effort
arm extending backward and then upward from the rotational center
of the lever, and a distance between an end of the effort arm and
the rotational center is greater than a distance between the
rotational center and the pushing member.
9. The appliance of claim 1, comprising: a pusher; the holder body
including a hole, the pusher coupled to the motor through the hole
of the holder body, wherein the pusher exerts a force to move the
lever when the motor is turned on.
10. A latch holder, comprising: a holder body; a latch passage
provided at a front of the holder body in which a latch comes in
and out, the latch passage including an inclined surface provided
at the latch passage; a hook accommodating space provided at a rear
of the latch passage; a lever supporting portion spaced apart from
the latch passage at a rear thereof; a lever that is swivably
supported by the lever supporting portion, wherein a pushing member
provided at a distal end of the lever is accommodated in a lower
part of the hook accommodating space; and a motor to drive the
lever such that the lever swivels and causes the pushing member to
lift to a position where the pushing member pushes the latch to
open a door by a predetermined angle.
11. The latch holder of claim 10, wherein the pushing member
includes an inner insertion member and an outer insertion member
into which the inner insertion member is inserted, the outer
insertion member pushes the latch in a direction where the door
opens while contacting the latch and moving.
12. The latch holder of claim 11, wherein the outer insertion
member includes a resin material and the inner insertion member
includes a metal material.
13. The latch holder of claim 10, comprising a covering plate
disposed laterally with respect to the latch passage in an offset
manner, the covering plate covers an inside of the latch holder
such that an inside of the latch holder is not seen through the
latch passage from the outside is provided on a front surface of
the lever supporting portion.
14. The latch holder of claim 10, wherein the lever is supported by
a lever shaft supporter that is provided on a second lateral
surface of the lever supporting portion and is swivably installed
near the second lateral surface of the lever supporting portion,
the lever provided with a shaft that is hinge-coupled to the lever
supporting portion and a load arm that extends from the shaft
forward, the pushing member extends from a distal end of the load
arm in a first lateral direction and is accommodated in a lower
part of the hook accommodating space.
15. The latch holder of claim 10, the pushing member further
comprising: an upper surface, a lower surface disposed in a lower
part of the upper surface and extends further forward than the
upper surface, a push-up inclined surface where a front end of the
upper surface inclinedly connects with a front end of the lower
surface, and a push-end part provided at a lower end of the push-up
inclined surface and protrudes furthest forward from the pushing
member, wherein, as the lever swivels, and the pushing member is
lifted, the latch that is accommodated and held in the hook
accommodating space receives force from the lever forward and
upward, is lifted and moves in a direction the door opens while
contacting the push-up inclined surface and moving from a boundary
between the upper surface and the push-up inclined surface to a
lower end of the push-up inclined surface.
16. The latch holder of claim 15, wherein the pushing member is
disposed further downward than a rotation center of the lever, and,
as the lever swivels, the push-end part is lifted above a height
corresponding to the rotation center of the lever, wherein the
height corresponds to the lever pushing the latch farthest away
from the pushing member.
17. The latch holder of claim 10, wherein the lever further
includes an effort arm that extends from a rotation center of the
lever and that receives force of swiveling the lever in a position
spaced apart from the rotation center, the effort arm and the
holder body are connected by a return spring applying force to the
effort arm in a direction where the pushing member moves
downward.
18. The latch holder of claim 17, wherein an opening sensing switch
that senses whether a door is closed is installed in a lower part
of the hook accommodating space, a trigger of the opening sensing
switch is disposed under the pushing member, the pushing member
that is moved downward by the return spring does not press the
trigger in the state where the latch is not drawn into the hook
accommodating space.
19. The latch holder of claim 17, wherein the effort arm is pressed
by a pusher in a direction opposite to a direction where the return
spring applies force, the pusher comprising: a rotating plate that
is rotated by the motor; a pusher cam that is placed eccentrically
from a rotation center of the rotating plate and that revolves as
the rotating plate rotates so as to press the effort arm or release
the same from the pressure; and a pressing boss that is
eccentrically placed from the rotation center of the rotating
plate; a return/stop switch installed in the holder body near the
pusher, the return/stop switch includes a trigger that is pressed
when the pressing boss is placed in a predetermined position and
that is not pressed when the pressing boss is not in the
predetermined position, as the rotating plate rotates.
20. The latch holder of claim 17, wherein a distance between an end
of the effort arm and the rotational center is greater than a
distance between the rotational center and the pushing member.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to and the benefit of
Korean Patent Application No. 10-2018-0035257, filed on Mar. 27,
2018, Korean Patent Application No. 10-2018-0038379, filed on Apr.
2, 2018 and Korean Patent Application No. 10-2018-0042414, filed on
Apr. 11, 2018, the entire content of which is hereby incorporated
by reference.
FIELD OF THE DISCLOSURE
[0002] The present disclosure relates to a home appliance that has
an automatic opening structure to automatically open a door of the
home appliance, and a door opening speed controller to control a
door opening speed.
BACKGROUND
[0003] A cooking appliance such as an oven or a microwave oven has
a rectangular cuboid shape and includes a cooking chamber that is
opened at the front and a door at the front of the cooking
chamber.
[0004] A door can open in many different ways. One example is a
hinge-coupled door that rotates about a rotational axis to open and
close the front of the cooking chamber. The door may have a handle
or a groove that can be gripped by a user.
[0005] For convenience, a function to automatically open and close
a door may be added to a cooking appliance. According to a known
automatic door opening structure of a cooking appliance, a high
output power driver is used to open a door in order to overcome
elasticity that is applied to the door so as to add closing force
to the door.
[0006] A known driver for supplying opening force to open a door is
installed near a rotational shaft of a door which has a narrow
space. This narrow space restricts the design and installation of
the driver. Additionally, the driver often operates incorrectly
because it is exposed to heat in a cooking chamber.
SUMMARY
[0007] In U.S. Patent Publication No. 2011-0095019, a controlled
door opening structure, in which latches of a swing door are lifted
by a cam so as to open a door, is disclosed. Two latches of the
swing door are provided in the upper and lower parts of one side of
the door and are linked with each other. The latches are connected
with each other such that one latch and the other latch can operate
simultaneously. The cam for opening the door lifts any one of the
two latches, and the lifted latch is pushed forward by an inclined
surface provided in the upper part of a latch holder so as to open
the door.
[0008] However, a structure in which latches are linked with each
other is a prerequisite for opening the door. That is, when one
latch is lifted, the other latch is also lifted.
[0009] Generally, latches on one side of a swing door may be linked
with each other without difficulty. However, in the case of a
pull-down door, a distance between two latches in the left and
right upper parts of the pull-down door of a cooking appliance is
longer than that between two latches of the swing door of a cooking
appliance. Accordingly, it is not simple to link with each other
the latches of a pull-down door of a cooking appliance. For
instance, if the two latches are to be linked with each other, a
structure of a door for shielding electromagnetic leakage and a
structure of a main body for shielding electromagnetic leakage, and
the like need to be redesigned. This is a cumbersome process. As a
result, a controlled door opening structure in U.S. Patent
Publication No. 2011-0095019 is hardly applied to a pull-down
door.
[0010] In an automatic opening structure of a pull-down door, it is
desirable that a structure for lifting the left latch and the right
latch, respectively, be applied on both sides of a main body of the
cooking appliance. However, space on both sides of the main body of
the cooking appliance with a pull-down door is smaller than that of
a cooking appliance with a swing-type door. Additionally, unless
both latches are lifted and unlocked simultaneously, automatic
opening of the door may not be smoothly performed.
[0011] According to the controlled door opening structure in U.S.
Patent Publication No. 2011-0095019, the force of lifting a latch
is implemented by means of a cam operation. A cam directly connects
to a driving means such as a motor, and the like, and five curved
profiles are radially provided in a circumferential surface of the
cam. Accordingly, a motor that generates as much power as the
driving force of the cam or a speed reducer is required.
Additionally, the driving system is very heavy. A heavy driving
system is greatly affected by inertial force. Thus, the cam may not
stop immediately at the correct position when the profile of the
cam has pressed a switch.
[0012] If the cam stops in the incorrect position, there may be a
problem when the door is closed. That is, even though the latch is
inserted into a latch holder when the door is closed, the force
that the lower end of a hook of the latch presses against the cam
may not be enough to rotate the heavy driving system. As a result,
the latch may not be completely mounted onto the latch holder to
lock onto the latch holder. This may cause a sensor for sensing
whether the door is closed or not to sense that the door is not
closed and may cause the cooking appliance to determine that the
door is not completely closed and not operate.
[0013] Most of the controlled door opening structures include a
motor, a cam that is rotated by the motor and a micro switch that
is pressed by the cam so as to control the rotational displacement
of the motor.
[0014] In U.S. Pat. No. 7,225,804, a method for monitoring a
mechanism for automatically opening a door with a motor driven
latch (locking member) is disclosed. The monitoring mechanism
confirms whether an oven door locking member is properly in the
locked or released position. When sensing that the oven door
locking member is in the incorrect position, the monitoring
mechanism supplies pulse signals to a motor repeatedly to place the
locking member in the correct position.
[0015] However, since changes in voltage supplied to the motor may
not have been considered, the position of the locking member may
not be constant with each single pulse signal of the monitoring
mechanism.
[0016] Additionally, according to the method, pulse signals are
supplied a number of times instead of uninterrupted signals so as
to allow the locking member to be placed in the correct position.
Thus, much time is spent on sensing failure because there are gaps
between signals.
[0017] The above-described method for sensing failure is performed
apart from the operation of the locking member. Thus, input power
for operating the locking member and pulse power for sensing a
failure of the locking member are separately used. This makes an
electric power source of the cooking appliance complicated.
[0018] If a pull-down door automatically opens by means of its
self-weight after the pull-down door is unlocked, the opening angle
of the door increases as the door opens, and accordingly, the
opening force of the door increases proportionally. In a hinge
module for controlling the opening speed of a door, a structure in
which elasticity is applied in a direction opposite to the
direction of the force of the opening door and a structure in which
damping force is applied in a direction opposite to the direction
of the force of the opening door are combined.
[0019] The hinge module is configured to have elasticity and
damping force small enough for most people not to feel the
self-weight of a door when they open the door. However, in a
structure where a door automatically opens from a closed position
to a completely opened position, the door opening speed is hardly
controlled.
[0020] For instance, when the damping force of the door is
increased to prevent an increase in the door opening speed, the
initial door opening speed is significantly decreased. Conversely,
when the damping force of the door is decreased to increase the
initial door opening speed, the door swings open with significant
force because the applied damping force is overwhelmed by the
opening force of the door increasing in accordance with an
increasing opening angle of the door.
[0021] In view of the exemplary problems described above, the
present disclosure provides a home appliance capable of
automatically opening a door even though an automatic door opening
structure provided with two latches moving independently is applied
only to any one latch.
[0022] The present disclosure provides a home appliance capable of
automatically opening a door with a low power driver.
[0023] The present disclosure provides a home appliance that is not
affected by heat in a cooking chamber, thereby ensuring a reliable
automatic opening.
[0024] The present disclosure provides a home appliance that has a
structure for automatically opening a door, which is not seen from
the outside, thereby ensuring a neat appearance of the home
appliance.
[0025] The present disclosure provides a door opening speed
controller capable of controlling door opening speed in an
automatic door opening structure in which the wider the door opens,
the bigger the opening force of the door is.
[0026] The present disclosure provides a door opening speed
controller enabling a door to smoothly open even when the door
initially opens and enables a door to slowly open at limited speed
while the opening of the door finishes in an automatic door opening
structure in which the wider the door opens, the bigger the opening
force of the door is.
[0027] The present disclosure provides a control method for an
automatic opening of a door of a home appliance including
uninterruptedly supplying signals using electric power
(uninterrupted square wave AC power) that is usually input to a
home appliance instead of repetitive pulse signals, so as to drive
a motor and guarantee that the motor and a driver relevant to the
motor is in the correct positions.
[0028] The present disclosure provides a control method for an
automatic opening of a door of a home appliance, including
confirming signals sensed by a monitoring device such as a switch
during a predetermined period of time using usual input signals so
as to monitor operation of an automatic door opening device without
generating error signals and driving a motor.
[0029] The present disclosure provides a control method for an
automatic opening of a door, including automatically opening a door
and simultaneously confirming whether there is an error in an
automatic door opening mechanism.
[0030] The present disclosure provides a door opening speed
controller that may ensure an initial opening speed of a door and
suppress an increase in a final opening speed of the door
sufficiently in automatic opening of a pull-down door.
[0031] The present disclosure includes a main body having a cavity
or cooking chamber therein, a door for opening and closing an open
front of the cavity or cooking chamber and a rotational axis member
serving as a center of rotation for opening and closing movements
of the door, wherein the rotational axis member swivably connects
the door to the main body around a horizontal rotation axis placed
in a front lower part of the main body and extending in the
left-right direction, wherein the door opens forward and downward
around the rotation axis and is applied to a home appliance
(domestic appliance) having a pull-down door the elasticity of
which is applied by a spring in the direction where the door is
closed.
[0032] An automatic door opening structure of the present
disclosure may be applied to a structure in which a latch extending
toward the main body and swiveling around a horizontal pivot shaft
in the door is provided on a surface of the door, which faces the
main body, and a latch holder that locks the latch so as to keep
the door closed or that unlocks the latch so as to open the door is
provided in a part of the main body, which corresponds to a
position in which the latch is provided, in the state where the
door is closed.
[0033] The present disclosure includes a lever that is installed in
the latch holder for pushing the latch drawn in a hook
accommodating space in the latch holder in the direction where the
door opens and that allows the latch to be released from the latch
holder.
[0034] To this end, the lever pushes the latch in the direction
where the door opens while lifting the latch. The force that the
door opens by means of the self-weight is greater than force
applied by the spring at an angle (a1) where the door slightly
opens by the lever. Accordingly, the door opens by means of the
self-weight thereof.
[0035] In the structure, the lever is not exposed to the outside.
Thus, even though an automatic door opening structure is applied to
a product, the product may have a neat appearance and may provide
emotional quality.
[0036] Additionally, the door may open automatically by means of
the self-weight thereof without being driven to open completely,
thereby implementing an automatic door opening structure
readily.
[0037] The latch is provided on both sides of the door, and the two
latches swivel independently. The lever may be provided only at any
one of the latch holders of the two latches. That is, according to
the present disclosure, pushing any one of the two latches
operating independently allows all the two latches to be
released.
[0038] If the door opens downward by means of the self-weight
without damping, the door or a part where the door and the main
body are connected is seriously affected by the slamming of the
door.
[0039] A door opening speed controller of the present disclosure
allows damping force to act in a direction opposite to the
direction in which the door opens from an opening angle (a2)
greater than the opening angle (a1) to a complete opening angle
(a3).
[0040] The opening angle (a2) at which damping force starts to act
ranges from 30.degree. to 40.degree. such that the door receives
enough damping force and opens slowly, but does not open too
slowly.
[0041] A hinge module may be installed respectively at the lower
end of one side of the door and at the lower end of the other side
of the door. A damping start angle (a2) of any one of the hinge
modules may range from 30.degree. to 40.degree. while a damping
start angle (a2') of the other hinge module may range from
60.degree. to 80.degree..
[0042] That is, a damper in the hinge module at the lower end of
one side of the door starts to provide damping force when an
opening angle of the door is at a damping start angle (a2) while a
damper in the hinge module at the lower end of the other side of
the door starts to provide damping force when an opening angle of
the door is at an additional damping start angle (a2') greater than
the damping start angle (a2).
[0043] The hinge module may include a housing extending forward and
backward and fixed to the main body; a door bar swivably connected
to the housing around a rotational axis member and fixed to the
door; an inner link housing swivably connected to the door bar
through a door bar connecting hinge and guided by the housing so as
to move forward and backward; and a damper including a piston and a
cylinder and providing damping force according to a relative
movement of the piston and the cylinder.
[0044] The door bar connecting hinge may be spaced a predetermined
distance (r, r') apart from the rotational axis member.
[0045] Any one of the piston and the cylinder of the damper moves
forward as the inner link housing moves forward, and the other of
the piston and the cylinder of the damper moves forward by a
predetermined distance (d2, d2') as the inner link housing moves
forward and then is interfered by the housing not to move further
forward.
[0046] According to the present disclosure, a predetermined
distance (d2) of the hinge module on one side of the door is
shorter than a predetermined distance (d2') of the hinge module on
the other side of the door such that damping start angles (a2, a2')
of the two hinge modules differ.
[0047] Specifically, the damper may further include a slot provided
in the other of the piston and the cylinder of the damper and
extending forward and backward and a damper support pin installed
in the housing and fitted into the slot. The predetermined
distances (d2, d2') may be determined based on a length of the
slot.
[0048] Next, a distance (r) between the door bar connecting hinge
and the rotational axis member of the hinge module installed on one
side of the door may be longer than a distance (r') between the
door bar connecting hinge 831 and the rotational axis member of the
hinge module installed on the other side of the door.
[0049] If there is a difference in the distances between the door
bar connecting hinge 831 and the rotational axis member, a distance
moved by the inner link housing at the same opening angle of the
door differs. With this structure, the damping start angles (a2,
a2') of the two hinge modules may differ.
[0050] Of course, the method of making lengths of the slots of the
two hinge modules different from each other and the method of
making the distance between rotational axis member and the door bar
connecting hinge of the two hinge modules different from each other
may be applied together.
[0051] A stroke of the damper of the hinge module installed on one
side of the door and a stroke of the damper of the hinge module
installed on the other side of the door may be differentiated at
the same opening angle of the door. As an example, a distance
between the door bar connecting hinge and the rotational axis
member of the hinge module may be adjusted.
[0052] If the stroke of each damper differs at the same opening
angle of the door, damping force applied to the door by each hinge
module may differ even though the same damper is used for two hinge
modules. That is, even though the damping coefficient of the damper
of the hinge module installed on one side of the door and the
damping coefficient of the damper of the hinge module installed on
the other side of the door are substantially the same, damping
forces (Fd1, Fd2) applied at different moments may differ by
differentiating strokes of dampers at the same opening angle of the
door. The damping force may be removed at an angle that is
0.degree. to 5.degree. less than a maximum opening angle (a3) of
the door such that the door completely opens.
[0053] The latch includes a latch bar extending from the door
toward the main body and a hook member protruding downward from the
end of the latch bar.
[0054] Force is applied to the latch in the direction in which the
hook member moves downward. A rear inclined surface extending from
the lower end of the hook member toward the latch bar is provided
on the rear surface of the hook member, which closely faces the
door and, in the state where the door is closed, keeps interfering
with an inner inclined surface of the latch holder.
[0055] The inner inclined surface is inclined upward from the main
body toward the door so as to correspond to the rear inclined
surface such that the user may manually open the latch holder
having an automatic opening structure.
[0056] The latch may not be released from the latch holder only by
means of a lift of the latch performed by the lever. The latch has
to be able to be pushed in the direction in which the door opens
while being lifted by the lever. Accordingly, the lever pushes the
latch upward in the diagonal direction between the forward
direction and the upward direction. Then the latch may pass a
structure that holds the latch and escape from the latch
holder.
[0057] The lever is provided with a pushing member contacting the
latch, the pushing member is arranged further forward and downward
than the rotation center of the lever and is provided with a
push-up inclined surface having a normal line facing the front
upper part at the front end thereof, and the push-up inclined
surface may include a curved surface.
[0058] Accordingly, a low distal end inclined surface having a
normal line facing the rear lower part and contacting the push-up
inclined surface may be provided at the lower distal end of the
latch, and an upper inclined surface that is inclined downward when
the upper inclined surface becomes farther away from the door may
be provided at the upper distal end of the latch.
[0059] A latch passage that is a passage for drawing the latch into
and out of the hook accommodating space is provided at the front of
the latch holder.
[0060] Even though the door is prevented from opening due to
interference that happens in the direction where the door opens,
and the upper surface of the latch contacts the ceiling of the
latch passage and may not move further upward while the latch is
moved forward and upward and pushed from the latch holder by the
lever, when the lever continues to push the latch forward and lift
the same, the latch may finally slide in the direction where the
door opens and push the door in the state where the upper surface
of the latch contacts the ceiling.
[0061] That is, the upper inclined surface provided at the upper
distal end of the latch contacts an upper ceiling that is the
ceiling of the latch passage in the state where the latch is lifted
by the lever and then moves in the direction where the door opens
while contacting the ceiling of the passage for a latch so as to
allow the force that the lever pushes the latch to be smoothly
delivered to the door.
[0062] The latch is mounted onto an outer inclined surface provided
on the bottom of the latch passage provided at the front of the
latch holder by means of elasticity after the latch is released by
the lever and pushed in the direction where the door opens. The
outer inclined surface is inclined downward from the main body to
the door. Thus, the latch does not prevent the opening of the door
but, rather, pushes the door further outward by means of the
interaction between the force that the latch moves downward and the
outer inclined surface while the door opens.
[0063] A latch holder for the above-described door opening
mechanism includes a holder body constituting an entire frame of
the latch holder; a latch passage provided at the front of the
holder body and allowing a latch to come in and out; an outer
inclined surface provided in the lower part of the latch passage
and inclined downward toward the forward direction; an upper
ceiling provided in the upper part of the latch passage; a lever
supporting portion spaced apart from the latch passage at the rear
thereof; a hook accommodating space provided between the latch
passage and the lever supporting portion; a lever swivably
supported by the lever supporting portion and having a pushing
member that is provided at the distal end the lever and
accommodated in the lower part of the hook accommodating space; a
pusher swiveling the lever supporting portion so as to lift the
lever; and a pusher driver driving the pusher.
[0064] The pushing member includes an inner insertion member
provided at the distal end of the lever and an outer insertion
member into which the inner insertion member is inserted and allows
the outer insertion member to push the latch in the direction in
which the door opens while the outer insertion member contacts the
latch and moves. Preferably, the outer insertion member and the
lever may be optionally based on different materials in accordance
with the properties of each of the components.
[0065] Preferably, the outer insertion member is based on a resin
material such that the outer insertion member has wear resistance
higher than that of the inner insertion member, a coefficient of
friction lower than that of the inner insertion member and a
surface more lubricated that that of the inner insertion
member.
[0066] A covering plate that covers the inside of the latch holder
such that the inside of the latch holder may not be seen through
the latch passage from the outside is provided on the front surface
of the lever supporting portion, thereby ensuring a neat appearance
of a home appliance.
[0067] The lever is supported by a second lever shaft supporter
provided on a second lateral surface of the lever supporting
portion and swivably installed near the second lateral surface of
the lever supporting portion. The lever is provided with a shaft
hinge-coupled to the lever supporting portion and a load arm
extending from the shaft forward.
[0068] The lever may be disposed by detouring the covering plate,
and accordingly, the pushing member may extend from the distal end
of the load arm in the first lateral direction so as to be
accommodated in the lower part of the hook accommodating space.
[0069] The covering plate is disposed laterally with respect to the
latch passage in an offset manner. Thus, even though the pushing
member is disposed by detouring the covering plate, the degree at
which the pushing member is eccentrically placed from the load arm
of the lever in the lateral direction may be minimized.
[0070] The pushing member further includes an upper surface, a
lower surface disposed in the lower part of the upper surface and
extending further forward than the upper surface, a push-up
inclined surface where the front end of the upper surface and the
front end of the lower surface are inclinedly connected and a
push-end part provided at the lower end of the push-up inclined
surface and protruding furthest forward from the pushing
member.
[0071] As the lever swivels, and the pushing member is lifted, the
latch accommodated and held in the hook accommodating space
receives force from the lever and is lifted while contacting the
push-up inclined surface and moving from the boundary between the
upper surface and the push-up inclined surface to the lower end of
the push-up inclined surface.
[0072] The pushing member is disposed further downward than the
rotation center of the lever, and the push-end part is lifted up to
a height greater than a height corresponding to the rotation center
of the lever as the lever swivels. Accordingly, the pushing member
pushes the lever upward and outward.
[0073] The lever further includes an effort arm extending from the
rotation center of the lever and receiving the force of swiveling
the lever in a position spaced apart from the rotation center. The
effort arm and the holder body are connected by a return spring
applying force to the effort arm in the direction where the pushing
member moves downward.
[0074] An opening sensing switch for sensing whether the door is
closed is installed in the lower part of the hook accommodating
space, and a trigger of the opening sensing switch is disposed in
the lower part of the pushing member. In the state where the latch
is not drawn into the hook accommodating space, the pushing member
moved downward by the return spring is not allowed to press the
trigger, thereby preventing the pushing member from solely pressing
the opening sensing switch. As a result, the home appliance is
prevented from operating incorrectly.
[0075] The effort arm is pressed by the pusher in a direction
opposite to the direction in which the return spring applies force.
Accordingly, the effort arm is moved by force that is generated
when the pusher presses the effort arm while the force overcomes
the restoring force of the return spring, and then the lever
swivels such that the pushing member lifts the latch. Additionally,
when the pusher returns, the lever is returned to an initial
position by the return spring.
[0076] The pusher includes a rotating plate rotated by a motor; a
pusher cam placed eccentrically from the rotation center of the
rotating plate and revolving as the rotating plate rotates so as to
press the effort arm and release the same from the pressure. Thus,
based on the rotational displacement of the rotating plate, the
pusher cam presses the lever or releases the same from the
pressure.
[0077] The rotating plate further includes a pressing boss
eccentrically placed from the rotation center of the rotating plate
and placed in a position where the pressing boss avoids the lever
even though the pressing boss revolves as the rotating plate
rotates, and a return/stop switch having a trigger, pressed when
the pressing boss is placed in a predetermined position after the
rotating plate rotates and not pressed when the pressing boss
escapes from the predetermined position, is provided near the
pusher so as to control rotation of the rotating plate and control
where the rotating plate stops.
[0078] When the trigger of the return/stop switch is pressed, a
pusher driver for driving the pusher is allowed to stop, such that
the operation of the pusher is exactly controlled by a
controller.
[0079] According to the present disclosure, a control method for an
automatic opening of a door may be applied to a main body 710
having a cooking chamber therein and the above-described automatic
opening structure of a home appliance.
[0080] According to the present disclosure, a control method for an
automatic opening of a door includes controlling the lever, the
pusher and the pusher driver by the controller so as to arrange the
same in the correct positions when electric power is supplied to
the cooking appliance, or the user turns on the home appliance.
[0081] The pusher connected with the motor is arranged in a
position where the pusher presses the return/stop switch, that is,
the return/stop switch is on. When the door opens, the motor moves
the pusher and then moves the pusher to a position where the pusher
presses the return/stop switch again.
[0082] There are times when the pusher is not in the correct
position when the home appliance initially operates (the moment
when electric power starts to be supplied, the moment when the
power button is pressed, and the like). According to the present
disclosure, even in this case, the pusher may be arranged in the
correct position. If the pusher is not in the position where the
return/stop switch is on when the home appliance starts to operate,
electric power is supplied to the motor, and then the motor rotates
until the pusher presses the return/stop switch. When the motor
rotates, and then the pusher presses the return/stop switch, the
electric power being supplied to the motor is cut off.
[0083] Electric power supplied to the home appliance, i.e., AC
power may be used as power supplied to the motor. The power is
supplied in an uninterrupted manner not in the form of pulses or in
a sporadic manner.
[0084] The above-described initial arrangement of the pusher in the
correct position is meaningful in the application of a method for
uninterruptedly supplying electric power to the motor of the latch
holder.
[0085] According to the present disclosure, in driving the latch
holder, the correct position of the pusher has to be figured out,
and the pusher is required to be arranged in the correct position.
To this end, in the control method for an automatic opening of a
door, the controller continuously monitors a period in which
electric power is supplied to the motor, the state where the
return/stop switch is on/off and the state where the opening
sensing switch is on/off. As a result, an automatic opening of a
door may be exactly controlled. Additionally, an arrangement of the
pusher in the correct position and an automatic opening of the door
may be controlled without a sensor for confirming whether the motor
rotates.
[0086] According to the latch holder, the pusher moves to a
position where the pusher presses the return/stop switch by means
of the pressing force applied to the lever by the hook member of
the latch while being linked with the latch when the latch is
accommodated in the latch holder and locked by the latch
holder.
[0087] Thus, if the door is correctly closed, the pusher in the
latch holder maintains the initial correct position.
[0088] At the time of the initial operation of the home appliance,
the door may be opened or closed. Even though the door is open, the
pusher may be out of the position where the pusher presses the
return/stop switch due to a power outage, and the like.
[0089] For this reason, the controller according to the present
disclosure controls the pusher to arrange the same at the time of
the initial operation of the home appliance. According to the
present disclosure, a control method for an automatic opening of a
door includes step 1 of confirming whether a return/stop switch is
on when a home appliance is turned on; step 2 of supplying electric
power to a motor when the return/stop switch is off in step 1; step
3 of confirming whether the return/stop switch is on after a
predetermined period of time (t.sub.0) passes following step 2 of
supplying electric power to a motor; step 4-1 of returning to step
1 when the controller confirms that the return/stop switch is
turned on in step 3.
[0090] With the above-described control algorithm, the pusher may
be arranged in the correct position at the time of the initial
operation of the home appliance.
[0091] When the controller confirms that the return/stop switch is
kept off in step 3, the return/stop switch or the motor is
operating incorrectly. Accordingly, the control method may further
include step 4-2 of generating a fourth error signal of a problem
with the return/stop switch or the motor and stopping the operation
of the home appliance.
[0092] When the controller confirms that the return/stop switch is
on in step 1, the pusher is already in the correct position. Thus,
there is no need to arrange the pusher in the correct position. If
the pusher is arranged even though the pusher is arranged in the
correct position, a closed door may open.
[0093] According to the latch holder of the present disclosure, the
pusher is arranged in the correct position by means of the linkage
between the lever and the pusher in the state where the door is
closed. Thus, the pusher is not required to be arranged when the
controller confirms that the return/stop switch is pressed at the
time of the initial operation of the home appliance.
[0094] When the pusher is arranged in the initial correct position,
the controller is in a wait state until the user inputs an
instruction to open the door through an input part such as a touch
panel, and the like. As described above, the controller continues
to monitor the state where the return/stop switch and the opening
sensing switch are on/off and whether electric power is supplied to
the motor after the home appliance starts to operate.
[0095] When the user inputs an instruction to open the door after
the controller confirms that the pusher is in the correct position
in step 1, and step 5 in which the controller is in a wait state
until the user inputs the instruction to open the door starts, an
automatic opening of the door starts to be controlled, regardless
of whether the pusher is arranged so as to be in the correct
position, or whether the pusher is not arranged because the pusher
is already in the correct position.
[0096] To this end, the control method for an automatic opening of
a door includes step 6 of supplying electric power to the motor and
confirming whether the return/stop switch is turned off, when the
user inputs an instruction to open the door in step 5.
[0097] When the controller confirms that the return/stop switch is
turned off in step 6, the motor is normally operating. In this
case, the control method includes step 7 of confirming whether the
opening sensing switch is turned off after a predetermined period
of time.
[0098] When the controller confirms that the opening sensing switch
is turned off in step 7, the lever normally pushes the latch, and
the latch is released from the latch holder. In this case, the
control method includes step 8 of confirming whether the
return/stop switch is turned on.
[0099] When the controller confirms that the return/stop switch is
turned on in step 8, the return/stop switch is normally operating.
In this case, the control method includes step 9-1 of returning to
step 1.
[0100] Steps 6, 7, 8 and 9-1 may be carried out when the normal
operation of the motor, the normal opening of the door (release of
the latch) and the normal operation of the return/stop switch are
all confirmed through monitoring signals (signals from the
return/stop switch and the opening sensing switch, a period in
which electric power is supplied to the motor).
[0101] When the return/stop switch is turned off in step 6, the
motor operated when electric power was supplied to the motor.
Accordingly, the motor is normally operating. However, when the
return/stop switch is kept on, the motor didn't operate even when
electric power was supplied to the motor. In this case, the motor
is operating incorrectly.
[0102] When the return/stop switch is kept off after a
predetermined period of time (long enough for the pusher to operate
and to return to the correct position by means of the motor) even
though the return/stop switch was turned off in step 6, the motor
is normally operating, and the return/stop switch is normally
operating because the return/stop switch senses that the motor is
normally operating. However, there is a problem with the opening of
the door or the operation of the latch such as a problem that the
latch may not escape from the latch holder, and the like.
[0103] When the return/stop switch is kept off after a
predetermined period of time (long enough for the pusher to operate
and to return to the correct position by means of the motor) even
though the return/stop switch was turned off, and the opening
sensing switch was turned off, in step 6, the motor is smoothly
operating, and accordingly, the latch is normally released from the
latch holder. However, the return/stop switch could not sense that
the pusher returned to the initial position. In this case, the
return/stop switch is operating incorrectly.
[0104] If the opening sensing switch is turned off after a
predetermined period of time even though the return/stop switch is
kept on in step 6, the motor is normally operating, and
accordingly, the latch is normally released from the latch holder.
However, the return/stop switch could not sense that the pusher is
placed in the position where the pusher does not press the
return/stop switch by means of the normal operation of the motor
and the pusher. In this case, the return/stop switch is operating
incorrectly.
[0105] The algorithm and sequence performed by a controller are
described as follows.
[0106] When the return/stop switch is kept off in step 8, even
after electric power is supplied to the motor with an instruction
to open the door input by the user, the return/stop switch is
turned off, and following a predetermined period of time, the
opening sensing switch is turned off, the controller may determine
the return/stop switch is operating incorrectly, generate a second
error signal and finish operation of the home appliance.
[0107] When the opening sensing switch is kept on after a
predetermined period of time, even after electric power is supplied
to the motor with an instruction to open the door input by the
user, and the return/stop switch is turned off, the controller may
determine there is a problem with the operation of the latch,
generate a first error signal and stop the operation of the home
appliance.
[0108] When the return/stop switch is kept on, even after electric
power is supplied to the motor with an instruction to open the door
input by the user, the controller may determine there is a problem
with the motor or the return/stop switch and generate an error
signal.
[0109] The order of determining which of the motor and the
return/stop switch is operating incorrectly is described as
follows. The determination may be made after it is confirmed that
the opening sensing switch having been kept on by the closed door
is turned off, following a predetermined period of time (long
enough for the motor to rotate so as to operate the pusher and long
enough for the lever to push the latch from the latch holder when
the motor normally operates).
[0110] According to the present disclosure, the control method
includes step 12 of confirming whether the opening sensing switch
is turned off after a predetermined period of time if the opening
sensing switch was on by the closed door when electric power
started to be supplied to the motor in step 6.
[0111] When the controller confirms that the opening sensing switch
is turned off in step 12, the motor is normally operating while the
return/stop switch is operating incorrectly. Accordingly, the
control method may include step 13-1 of generating a second error
signal of a problem with the return/stop switch.
[0112] Conversely, when the controller confirms that the opening
sensing switch is kept on in step 12, the motor is operating
incorrectly. Accordingly, the control method may include step 13-2
of generating a third error signal of a problem with the motor.
[0113] As described above, when determining which of the motor and
the return/stop switch is operating incorrectly, it is confirmed
that a closed door normally opens. Thus, when the opening sensing
switch is already off (the door is open) from the moment when
electric power is supplied to the motor, it is difficult to confirm
which of the motor and the return/stop switch is operating
incorrectly. In this case, the controller may generate a fourth
error signal of a problem with any one of the motor and the
return/stop switch.
[0114] The error signals may be shown on a display, and the like,
or an alarm may be used as the error signals.
[0115] According to the present disclosure, a structure for an
automatic opening of a door provided with a pair of latches moving
independently may be implemented only with the installation and
operation of a lever applied to any one latch holder. Accordingly,
a door may automatically open with no need to link a pair of
latches and apply an opening structure to all the two latches,
thereby making it possible to simply design a door and ensure
greater space for a cavity of a home appliance.
[0116] Additionally, according to the present disclosure, a lever
is used to increase the opening force of a door, and a door
initially opens to a position where the door automatically opens by
means of the self-weight, thereby making it possible to
automatically open a door only with a low output power driver.
[0117] Additionally, according to the present disclosure, since a
driving system itself is light, a lever and a pusher may be
rearranged in the correct positions by means of the pressing force
applied to the lever by a latch even though the lever and the
pusher slightly escape from the correct positions when the latch is
accommodated in a latch holder by closing a door, thereby making it
possible to smoothly close a door.
[0118] Additionally, an automatic opening structure of the present
disclosure is installed in a position not affected by heat of a
cooking chamber, and components thereof are not exposed to the
outside, thereby making it possible to prevent a home appliance
from operating incorrectly and to ensure a neat appearance of a
home appliance.
[0119] A door opening speed controller of the present disclosure
enables a door to smoothly open even when the door initially opens
and enables a door to slowly open while the opening of the door
finishes in an automatic door opening structure in which the wider
the door opens, the bigger the opening force of a door is, thereby
making it possible to control an automatic opening of a door and to
smoothly open the door.
[0120] According to a control method for an automatic opening of a
door of a home appliance of the present disclosure, usual electric
power is supplied to a motor with no need to generate another type
of power in addition to uninterrupted AC power usually supplied to
a home appliance, and errors or abnormalities of each component of
an automatic door opening device may be monitored only through
signals from a return/stop switch for determining where a motor
stops and an opening sensing switch for confirming whether a door
opens. That is, according to the control method of the present
disclosure, an automatic opening may be exactly controlled without
a sensor for confirming whether a motor operates or a sensor for
confirming whether a latch stays in the correct position in a latch
holder.
[0121] Additionally, according to the present disclosure, power
supplied to a motor and signals from a return/stop switch and an
opening sensing switch may be continuously monitored while a door
automatically opens with no need to confirm errors in the automatic
opening of a door, thereby making it possible to confirm whether
the door operates correctly in real time.
[0122] Further, according to the control method of the present
disclosure, an automatic opening of a door may be exactly
controlled simply with a motor and a pusher (cam), a lever and a
return/stop switch in addition to a conventional latch holder in
the absence of a sensor or a controlling means.
BRIEF DESCRIPTION OF THE DRAWINGS
[0123] FIG. 1 is a perspective view illustrating a latch holder to
which an automatic opening structure of a cooking appliance
according to an embodiment of the invention is applied.
[0124] FIG. 2 is an exploded perspective view illustrating the
latch holder in FIG. 1.
[0125] FIG. 3 is a perspective view illustrating a holder body of
the latch holder in FIG. 2.
[0126] FIG. 4 is an enlarged view illustrating a shaft, a load arm
and a pushing member of a lever of the latch holder in FIG. 2.
[0127] FIG. 5 is a side view illustrating the latch holder in FIG.
1.
[0128] FIG. 6 is a view illustrating a state where a pusher in FIG.
5 pushes the lever and the pushing member of the lever is
lifted.
[0129] FIG. 7 is a view illustrating a state where the pusher and
the lever are returned to initial positions thereof in the state
where a latch is released.
[0130] FIG. 8 is a side view illustrating a state where a door of a
front of a cavity of a cooking appliance in which the latch holder
is installed is closed and the latch is inserted into and fixed in
the latch holder.
[0131] FIG. 9 is a view illustrating a process in which the pusher
pushes the lever such that a push-up inclined surface of the
pushing member of the lever lifts the latch in FIG. 8.
[0132] FIG. 10 is a view illustrating a process in which the
push-end part of the lever pushes the latch after the process of
lifting the latch in FIG. 9 further proceeds.
[0133] FIG. 11 is a view illustrating a state where the latch moves
downward and is disposed onto an outer inclined surface after the
latch is pushed away.
[0134] FIG. 12 is a view illustrating a process in which the door
opens by means of self-weight after the latch is released from the
latch holder as in FIG. 11.
[0135] FIG. 13 is a perspective view illustrating a structure of a
hinge according to an embodiment of the invention used to move the
door downward by means of self-weight and allow the door to open
automatically as in FIG. 12.
[0136] FIG. 14 is a side view illustrating the structure of the
door hinge in FIG. 13.
[0137] FIG. 15 is a view illustrating a structure in which a slot
of a cylinder extends so as to delay interference of a damper in an
opening of the door in the structure of the door hinge.
[0138] FIG. 16 is a view illustrating a structure in which a
distance between a rotational axis member and a door bar connecting
hinge is shortened so as to delay interference of a damper in an
opening of the door in the structure of the door hinge.
[0139] FIG. 17 is a view illustrating an opening force of the door,
resistance of a spring against the opening force and damping force
of a damper based on an opening angle of the door.
[0140] FIG. 18 is a view illustrating a geometric shape of a lever
according to an embodiment of the invention.
[0141] FIG. 19 is a flow chart illustrating a control method for an
automatic opening structure of a cooking appliance according to an
embodiment of the invention.
[0142] FIG. 20 is a flow chart illustrating the steps of generating
error signals in FIG. 19.
[0143] FIG. 21 is a flow chart illustrating a process of arranging
a motor and a pusher in a correct position at the time of initially
operating the cooking appliance in FIG. 19.
[0144] FIG. 22 is a block diagram of an electronic system to
implement an automatic opening structure and the control method in
FIGS. 19 to 21 according to an embodiment of the invention.
DETAILED DESCRIPTION
[0145] Implementations of the present disclosure will now be
described with reference to the attached drawings.
[0146] The present disclosure may be implemented in many different
forms and accordingly, is not limited to the implementations set
forth hereunder. Features illustrated in the drawings may be
combined or omitted as needed in order to achieve a desired
purpose. Further, the implementations are provided to make the
present disclosure thorough and complete to one having ordinary
skill in the art to which the present disclosure pertains.
[0147] Referring now to FIG. 12, a cooking appliance is
illustrated. However, the implementations of the present disclosure
is not limited to a cooking appliance. The implementations of the
present disclosure can be applied to other appliances with
pull-down doors. An appliance can be that used in a home or
commercially.
[0148] The cooking appliance includes a main body 710 that has an
approximately rectangular cuboid shape, that is hollow inside and
an open front. A door 720 is installed at the open front of the
main body 710.
[0149] The main body 710 includes an outer housing defining an
outer appearance of the cooking appliance, and an inner housing
forming a cavity that is opened in the front. In this embodiment,
the cavity may be a cooking chamber. The main body 710 further
includes various components required for operating the cooking
appliance.
[0150] The door 720 is a pull-down type opening and closing
structure which rotates about a horizontal hinge shaft 814 (see
FIGS. 13 and 14) that is provided at a lower end of the door. The
door 720 swivels forward and downward with respect to the main body
so as to be opened and swivels rearward and upward with respect to
the main body so as to be closed.
[0151] A surface area of a door may simply be a surface area for
opening and closing the front of the cooking chamber.
Alternatively, as illustrated in FIG. 12, the door 720 may have a
surface area for entirely closing the front of an upper space above
the cooking chamber as well as the cooking chamber. A display, a
touch panel, and the like may be installed on the front surface of
the door 720 corresponding to the upper space above the cooking
chamber. The display and the touch panel connect with a controller
90 (see FIG. 22). The controller 90 may be installed in the upper
space above the cooking chamber or an inner space of the door 720
corresponding to the upper space above the cooking chamber.
[0152] A latch holder 10 for keeping the door 720 closed and
allowing the door to automatically open is provided at an upper
part of the main body 710 in the lateral direction of the main
body. A latch 200 that is locked by the latch holder 10 so as to
keep the door closed and that is released from the latch holder 10
so as to open the door is provided at the door 720.
[0153] The latch 200 protrudes from a back surface of the door 720
facing the main body 710 from upper portions of both ends of the
door 720. The latch holder 10 at the main body 710 is arranged at
front upper parts of both ends of the main body, corresponding to
the positions where the latch is installed at the upper portions of
both ends of the door 720. The latch holder 10 is provided with a
latch passage 110 (see FIG. 3) opened forward to allow the latch to
come in and out of the latch holder 10.
[0154] A latch holder 10 with a mechanism for automatically
releasing a locked latch may be provided for any one of two latches
200 at the door 720, and another latch holder without a mechanism
for automatically releasing a locked latch may be provided for the
other latch 200. The two latches 200 may be installed at the door
720 such that they may independently move upward and downward. The
two latches 720 may be elastically supported at the door, for
example, using springs, with hook members at the distal ends of the
two latches facing downward. The elasticity applied to the two
latches may be the same or they may be different.
[0155] Referring now to FIGS. 13 and 14, a hinge module 800 in
which a spring 823 and a damper 850 are installed is connected to a
front lower part of the main body and a lower part of the door. The
spring 823 applies force to the door in the direction in which the
door 720 swivels backward and upward, i.e., in the direction in
which the door is closed. Thus, the spring 823 applies force that
opposes the force generated by the door that is automatically
released and swivels forward and downward, i.e., in the direction
in which the door is opened.
[0156] The damper 850 reduces a rotational force of the door when
the door opens, thereby causing the door to open more slowly when
the damping force is applied. The damper 850 may provide damping
force only when the door opens or may provide damping force at all
points where the door is opening and closing. In this embodiment,
the damper may provide damping force in a range among all of the
swivel angles in which the door swivels so as to be opened and
closed
[0157] The damper 850 may damp the opening force of the door in a
range of predetermined opening angles in a section where the door
opens and may not damp the opening force of the door outside the
range of predetermined opening angles. For example, referring to
FIG. 12, a structure in which a damper operates in a range of
opening angles between a2 and a3 is illustrated. A damping start
angle (a2), at which damping starts as the door opens, may be
35.+-.5.degree. which continues until the door is fully opened at
end angle (a3).
[0158] Referring now to FIGS. 1 to 7, a latch holder with an
automatic door opening device according to an embodiment of the
invention will be described.
[0159] The latch holder includes a holder body 100 for supporting
an entire structure, a latch passage 110 provided at a front of the
holder body 100, and a lever 300, an opening sensing switch 400, a
pusher 500, and a pusher driver 600 installed at the holder body
100.
[0160] The latch passage 110 provides for a latch 200 of the door
720 to come in and out of the holder body 100. A hook accommodating
space 180 for accommodating a hook of the latch is provided in the
holder body 100 at the rear of the latch passage 110. An opening
sensing switch 400 is installed in a lower part of the holder body
100 below the hook accommodating space 180 for sensing whether the
hook of the latch has entered the hook accommodating space 180 and
held by the same.
[0161] A lever supporting portion 120 in which the lever 300 is
swivably installed is provided at the rear of the hook
accommodating space 180. The lever 300 is provided with a load arm
320 extending forward from the lever supporting portion 120, a
pushing member 330 laterally extending from a distal end of the
load arm 320 to occupy a lower space in the hook accommodating
space 180 and an effort arm 340 extending backward from the lever
supporting portion 120 and then extending upward.
[0162] The opening sensing switch 400 installed below the hook
accommodating space 180 is provided with a trigger 420 disposed to
be able to abut a lower surface 335 of the pushing member 330. The
trigger 420 is pressed by contacting the pushing member 330.
However, the force of pressing the trigger 420 is insufficient by
the pushing member 330 alone, and the force is supplied by the
latch 200 when accommodated in the hook accommodating space
180.
[0163] A pusher 500 for pushing the effort arm 340 of the lever 300
backward and a pusher driver 600 for supplying force for driving
the pusher 500 are installed at an upper part of the holder body
100 above the lever supporting portion 120. A motor 610 of the
pusher driver 600 is fixed onto a second lateral surface of the
holder body 100, and the pusher 500 is disposed on a first lateral
surface of the holder body 100 and rotatable by the motor 610. The
rotational displacement of the motor 610 is controlled by a
return/stop switch 620 and the controller 90. The rotational
displacement is controlled by pressing a trigger 622 of the
return/stop switch 620 by a pressing boss 530 installed in the
pusher 500 based on an angular displacement of the pusher 500.
[0164] The effort arm 340 of the lever 300 is connected to the
holder body 100 by a return spring 630 and receives force applied
forward by the return spring 630 to return to its initial position.
Below, each element of the latch holder according to the present
disclosure will be described.
[0165] A holder body 100 supporting an entire structure of the
latch holder includes a flat surface extending in the up-down
direction and in the front-rear direction, i.e. a base plate 101
including a flat surface having a normal line in the first lateral
direction and in the second lateral direction.
[0166] A latch passage 110 opened forward is provided in the front
lower part of the holder body 100. The latch passage 110 is a
passage for allowing a latch 200 to come into the holder body 100
from the front part of the holder body 100 or for allowing the
latch to escape the holder body 100 from the front part of the
holder body 100.
[0167] An outer inclined surface 111 defines a lower inclined
boundary of the latch passage 110, an upper ceiling 113 defines an
upper boundary of the latch passage 110, and side walls 114 define
side boundaries of the latch passage 110 in both lateral directions
thereof.
[0168] The outer inclined surface 111 inclined upward from the
front thereof to the rear thereof is provided in the lower part of
the latch passage 110. When the latch 200 comes into the holder
body 100, a low distal end inclined surface 232 of a hook member
230 (see FIG. 8) of the latch 200 rides on the outer inclined
surface 111.
[0169] An inner inclined surface 112 is provided at the rear end of
the outer inclined surface 111. The inner inclined surface 112 is
inclined upward from the rear thereof to the front thereof The
inner inclined surface 112 and the upper end of the outer inclined
surface 111 are connected with each other in the shape of a
smoothly curved surface.
[0170] The inner inclined surface 112 contacts a rear inclined
surface 231 of the hook member 230 of the latch 200 drawn in the
holder body 100 so as to prevent the latch 200 from escaping out of
the holder body 100. Additionally, the inner inclined surface 112
supplies an inclined surface so as to allow the rear inclined
surface 231 of the latch 200 to naturally slide upward when the
user pulls the door forward to open the door. The rear inclined
surface 231 may be a flat surface or a curved surface with a
slightly convex shape. That is, the rear inclined surface 231 has a
surface such that the user may manually open the door.
[0171] The upper ceiling 113 includes a horizontal ceiling provided
in the upper part of the latch passage 110. When the lever 300
pushes the latch 200 so as to automatically open the door, the
upper ceiling 113 contacts the upper surface of the latch 200, more
specifically, an upper inclined surface 221 of the latch 200, and
guides the upper inclined surface 221 so as to allow the upper
inclined surface 221 to slide forward and out of the holder body
100.
[0172] Both sides of the upper ceiling 113 and the outer inclined
surface 111 are vertically connected to each other by the side wall
114. A gap between two side walls 114 is greater than a width of
the latch 200. Thus, the two side walls 114 do not interfere with
the latch 200.
[0173] A covering plate 123 is provided at the rear of the latch
passage 110 to cover the inside of the latch passage when seen from
the front to the rear. The covering plate 123 includes a flat plate
shape having a normal line in the front-rear direction. The
covering plate 123 is spaced backward from the latch passage 110 so
as to form one boundary of the hook accommodating space 180. The
hook member 230 of the latch 200 is accommodated in the hook
accommodating space 180.
[0174] The covering plate 123 is perpendicularly connected to the
base plate 101 so as to reinforce the entire stiffness of the
holder body 100. A lever supporting portion 120 for rotatably
supporting the lever 300 is installed at the rear of the covering
plate. The lever 300 is an element for releasing a latch 200 locked
by the holder body 100.
[0175] The lever supporting portion 120 requires a certain level of
stiffness so as to support the lever. The stiffness may be
satisfied by the covering plate 123.
[0176] The lever 300 installed at the lever supporting portion 120
is disposed in a position where the lever 300 swivels without
interfering with the covering plate 123 and the lever supporting
portion 120. The lever supporting portion 120 is provided with an
extending member 121 extending from the base plate 101 and
connected to the covering plate 123, and a lever shaft supporter
122 is provided in the extending member 121 to rotatably support
the lever 300. The lever 300 is axially coupled to the lever shaft
supporter 122 so as to swivel. The level 300 may contact a second
lateral surface of the extending member 121 so as to be guided when
swiveling.
[0177] A pushing member 330 extends from the distal end of the
lever 300 in the first lateral direction. The pushing member 330 is
disposed in the hook accommodating space 180 provided between the
covering plate 123 and the latch passage 110.
[0178] The covering plate 123 may be disposed in the first lateral
direction of the latch passage 110 in an offset manner. This is to
minimize lateral eccentricity between the pushing member 330 and
the effort arm 340 of the lever 300, to which force is applied.
[0179] An opening sensing switch fixing portion 150 for fixing an
opening sensing switch 400 sensing whether the door is closed is
provided below the latch passage 110 and the lever supporting
portion 120. The opening sensing switch fixing portion 150 includes
a flat surface having a normal line in the lateral direction and
connects the lower part of the latch passage 110 and the lower part
of the lever supporting portion 120.
[0180] The opening sensing switch fixing portion 150 includes a
fixing wall 151 for fixing a switch body 410 of the opening sensing
switch 400 to the opening sensing switch fixing portion 150, and at
least a part of the fixing wall 151 may be connected to the lever
supporting portion 120.
[0181] A trigger 420 of the opening sensing switch 400 protrudes
upward toward the hook accommodating space 180 in the state where
the switch body 410 is installed in the opening sensing switch
fixing portion 150. The lever 300 has a path that presses the
trigger 420.
[0182] The holder body 100 further includes a pusher 500 for
pushing the lever 300 and a structure for supporting the pusher
driver 600.
[0183] The pusher 500 for pushing the lever 300 is installed in the
holder body 100 so as to swivel the lever 300 in the direction in
which the latch 200 is released from the holder body 100. To this
end, a pusher supporting portion 130 for supporting the pusher 500
is provided at the base plate 101. The pusher supporting portion
130 includes a hole 131 into which a rotating shaft 510 of the
pusher 500 is inserted and a first lateral surface facing a
rotating plate 520 of the pusher 500. The first lateral surface
also faces a pressing boss 530 provided on a second lateral surface
of the rotating plate 520.
[0184] A pusher driver fixing portion 170 for fixing the pusher
driver 600 driving the pusher 500 is included on a second lateral
surface opposite to the first lateral surface of the base plate
101, on which the pusher 500 is installed. The pusher driver 600
may be a rotating motor 610, and a housing of the motor 610 may be
fixed onto the second lateral surface of the base plate 101.
[0185] A return/stop switch fixing portion 160 for fixing the
return/stop switch 620 is provided at the base plate 101 of the
holder body 100. The return/stop switch 620 is provided with a
trigger 622 pressed by the pressing boss 530 of the pusher 500. The
trigger 622 is pressed by the pressing boss 530 in a position to
which the pusher 500 is required to return after pushing the lever
300, so as to stop the rotation of the motor 610. Accordingly, the
return/stop switch 620 is installed in a position where the trigger
622 is pressed by the pressing boss 530 in a position to which the
pusher 500 returns. The return/stop switch fixing portion 160 may
be provided in the upper part of the holder body 100 above the
pusher supporting portion 130.
[0186] A return spring supporting portion 140 is provided at the
holder body 100 so as to supply the force of returning the lever
300 to an initial position after the lever 300 pushes the latch
200. The return spring supporting portion 140 is closer to the
lever supporting portion 120 than the pusher supporting portion
130. The return spring supporting portion 140 may include a hook
hanger 141 for hooking a ring provided at one end of the return
spring 630.
[0187] A shaft hole 310 of the lever 300 joins with a lever shaft
supporter 122 of the holder body 100 to be swivably fixed to the
lever supporting portion 120. The lever shaft supporter 122
includes a shaft shape extending in the second lateral direction,
and the shaft hole 310 may have a hole shape so as to accommodate
the shaft shape of the lever shaft supporter 122. Conversely, the
lever shaft supporter 122 may have a hole shape, and the shaft hole
310 may instead have a shaft shape instead of a hole.
[0188] The lever 300 includes a load arm 320 extending forward from
the shaft hole 310. A pushing member 330 extending in the first
lateral direction is provided at the distal end of the load arm
320. The pushing member 330 is disposed in a hook accommodating
space 180 of the holder body 100 in the state where the lever 300
is installed in the holder body 100.
[0189] According to the embodiment, the lever 300 is made from a
material having stiffness because the lever delivers the force of
pushing the latch 200, and the pushing member 330 is made from a
material having high wear resistance and a low coefficient of
friction because the pushing member 330 slidably contacts the latch
200. The lever 300 may be made from a metallic material such as an
aluminum alloy, and the like.
[0190] The pushing member 330 may be made from a material the same
as that of the lever 300 or includes an inner insertion member 331
integrally formed with the lever 300 and an outer insertion member
332 into which the inner insertion member 331 is inserted. The
inner insertion member 331 ensures stiffness of the pushing member
330, and the outer insertion member 332 may be made from a material
having high wear resistance and a low coefficient of friction so as
to slidably contact the latch 200. The pushing member 330 slidably
contacts the latch 200 and moves upward, and a push-end part 336
definitively pushes the distal ends 232, 233 of the latch 200.
Thus, the surface of the outer insertion member 332 may be made
from a material with a high degree of surface hardness, high wear
resistance, a low coefficient of friction and lubricability,
thereby ensuring a reliable operation.
[0191] The inner insertion member 331 may be integrally formed with
the lever 300 using a metallic material such as an aluminum alloy,
and the like. Unlike the inner insertion member, the outer
insertion member 332 may be made from a resin material. Even though
elastic deformation and restoration of the outer insertion member
is repeated by the force applied to the outer insertion member 332
by the latch 200, the surface of the outer insertion member is
resilient because resin materials have a high degree of surface
hardness, are elastically deformed and restored, and are not easily
broken and crumbled, unlike metallic materials. As a result, even
when movably contacting the latch 200, the outer insertion member
332 pushes the latch 200 through the elastic deformation and
restoration thereof but does not break.
[0192] The pushing member 330 may be a single member made from a
metallic material. When the pushing member 330 directly contacts
the latch 200 for an extended period of time, any one of the
pushing member 330 and the latch 200 may be damaged, caused by
continuous contact between metallic materials, on the surface
thereof. Additionally, since metallic materials do not have as much
elasticity, unlike resin materials, the latch 200 may not be
smoothly released.
[0193] The pushing member 330 seen from the side may have the cross
section of an approximate trapezoid shape. The lower surface 335 of
the pushing member 330 is a pressing surface that presses the
trigger 420 of the opening sensing switch 400 positioned below the
pushing member 330. The upper surface 334 of the pushing member 330
is a surface on which the hook member 230 of the latch 200
accommodated in the hook accommodating space 180 is rested. The
latch 200 presses the pushing member 330 downward from the upper
surface of the pushing member 330, and the pushing member 330
presses the trigger 420 by means of the pressing force of the
latch.
[0194] In the state where only the pushing member 330 is placed on
the trigger 420 without the latch 200 on the pushing member 330,
the pushing member 330 cannot press the trigger 420 but just seats
on the trigger 420 because the force exerted by the load of the
pushing member 330 is insufficient to press down and activate the
trigger 420 of the switch body 410.
[0195] A push-up inclined surface 333 is provided on the front
surface of the pushing member 330. The lower end of the push-up
inclined surface 333 protrudes further forward than the upper end
thereof and has a shape that inclines further backward starting
from the lower end of the push-up inclined surface to the upper end
thereof. The push-up inclined surface 333 may have a curved profile
with a slightly convex shape and is a surface that slidably
contacts a low distal end inclined surface 232 of the latch 200 and
delivers force of the lever 300 to the latch 200. A push-end part
336 for pushing the distal end of the latch 200 to the very end is
provided by the lower end of the push-up inclined surface 333.
[0196] The lever 300 further includes an effort arm 340 extending
backward and then upward from the shaft hole 310. A distance
between the shaft hole 310 and an effort of the effort arm 340 is
greater than a distance between the shaft hole 310 and the pushing
member 330, thereby providing leverage so as to increase the force
of lifting and pushing the latch 200 applied by the pushing member
330. Thus, with this structure, a low-powered and lighter pusher
driver 600 may be used.
[0197] To make the latch holder more compact, the effort arm 340
may have an approximate "L" shape, and the effort may be provided
near the upper end of the effort arm 340. The effort arm 340
receives force from the pusher 500, and that force is delivered to
the pushing member 330.
[0198] The effort arm 340 includes a spring fixing portion 342
connected to one end of a return spring 630 that returns the lever
300 to an initial position when the pusher 500 no longer applies
force to the effort arm 340. The spring fixing portion 342 is
disposed closer to the shaft hole 310 than the effort of the effort
arm 340. A strong returning force is required when the lever 300
pushes the latch 200 while a strong returning force is not required
when the lever 300 returns to an initial position after pushing the
latch 200. Accordingly, the spring fixing portion 342 may be
disposed closer to the shaft hole 310 than the effort of the effort
arm 340. The spring fixing portion 342 may have a hook hanger shape
for hooking a ring provided at the other end of the return spring
630.
[0199] According to the embodiment, the return spring 630 supplies
force small enough to allow the lever 300 to return to an initial
position, but does not further apply force after that. That is, the
return spring 630 is prevented from continuously applying force to
the lever 300 having returned to an initial position such that the
return spring 630 provides additional force to the pushing member
330 of the lever 300 that presses the trigger 420 of the opening
sensing switch 400 without the presence of the latch 200.
[0200] The lever 300 includes a first surface facing the first
lateral direction and a second surface facing the second lateral
direction. The first surface is contacted and supported by a second
surface of the lever supporting portion 120, which faces the second
lateral direction.
[0201] The pusher 500 is an element for pushing an effort of the
lever 300 and is installed in the holder body 100. The pusher 500
is disposed near the effort arm 340 of the lever 300. The pusher
500 includes a rotating plate 520 having a normal line in a first
lateral direction and a plane shape, a rotating shaft 510 provided
at the center of a second lateral surface (surface facing a second
lateral direction) of the rotating plate, a pressing boss 530
eccentrically placed from the center of the second lateral surface
of the rotating plate, and a pusher cam 540 eccentrically placed
from the center of a first lateral surface (surface facing a first
lateral direction) of the rotating plate 520.
[0202] The rotating plate 520 has a flat discus shape, and the
effort arm 340 of the lever 300 is disposed so as to face the first
lateral surface of the rotating plate 520.
[0203] The rotating shaft 510 extends toward the second lateral
direction. That is, the rotating shaft 510 is a rotation center of
the rotating plate 520 that is disposed so as to extend laterally.
The distal end (end part far from the rotating plate) of the
rotating shaft 510 is inserted into and rotatably supported by a
hole 131 of the holder body. The rotating shaft 510 is fixed to a
rotating driving shaft 611 of the motor 610 provided opposite the
rotating plate 520 by means of a shaft coupling, and the holder
body 100 is placed between the rotating plate 520 and the motor
610.
[0204] The pressing boss 530 is connected to the base end (end part
close to the rotating plate) of the rotating shaft 510 and provided
at the second lateral surface of the rotating plate 520. The
pressing boss 530 is provided at any one part of the rotating plate
520 in the circumferential direction thereof. In this embodiment,
the pressing boss 530 is a wedge shape. However, other shapes may
be used. The outer end of the pressing boss 530 in the radial
direction thereof may be used to press the trigger 662 of the
return/stop switch 620. In this embodiment, the pressing boss 530
is provided with a pressing portion in a position where the
pressing boss may press the trigger 622 of the return/stop switch
620. While various shapes may be used, in this embodiment, the
pressing boss has a convexly curved portion 531 at the distal end
thereof for pressing the trigger 622 while rotating around the
rotating shaft 510. The curved portion 531 of the pressing boss 530
has a convex shape when seen at least laterally. The trigger 622 is
contacted and pressed along a convex shape of the curved portion
531.
[0205] The curved portion 531 includes curve profiles 5311 provided
on both sides thereof and a push maintaining profile 5312
connecting the curve profiles 5311. The push maintaining profile
5312 maintains the state where the trigger 622 is pressed even when
the rotating plate 520 rotates for a predetermined angle (a). Thus,
even though electric power being supplied to the motor 610 is cut
off as soon as the trigger 622 is pressed, the rotating plate 520
rotates further by the inertia of the motor 610 and the rotating
plate 520, and the pressing boss 530 may no longer press the
trigger 622, thereby releasing the trigger 622. The push
maintaining profile 5312 maintains the state where the pressing
boss presses the trigger even when the rotating plate rotates
further by the inertia of the motor and the rotating plate.
[0206] According to the embodiment, one rotation of the rotating
plate 520 is associated with the opening of the lever. Accordingly,
the one rotation of the rotating plate may be exactly controlled
with the structure of the push maintaining profile 5312.
[0207] In comparison, the cam in U.S. Patent Publication No.
2011-0095019 is heavy because the cam has a structure in which the
cam is directly connected to a driving portion, and one-fifth
rotation of the cam is associated with the upward movement of a
lever. Thus, the rotating cam might not stop in the correct
position but might rotate further. When the cam does not stop in
the correct position, the door is closed. In this case, the cam is
not likely to return to the correct position even though the latch
presses the cam.
[0208] The pusher cam 540 has a cylinder shape protruding and
extending from the first lateral surface of the rotating plate 520
in the first lateral direction. As the pusher 500 rotates, the
outer circumferential surface of the cylinder of the pusher cam 540
pushes the effort arm 340 of the lever 300 backward, which is
disposed close to the first lateral surface of the rotating plate
520.
[0209] The pusher driver 600 includes the motor 610 fixed onto the
second lateral surface of the holder body 100 and coupled to the
rotating shaft 510 of the pusher 500 penetrating the holder body
100. The return/stop switch 620 is fixed onto the first lateral
surface of the holder body 100 and controls the stop of the motor
610.
[0210] The housing 612 of the motor 610 is fixed to the holder body
100, and the rotating driving shaft 611 of the motor 610 is fixed
to the rotating shaft 510 of the pusher 500.
[0211] When the user inputs an instruction to automatically open
the door of the cooking appliance through an input part, electric
power is supplied to the motor 610, and the rotating driving shaft
611 rotates. Then the motor 610 rotates until the pressing boss 530
of the pusher 500 presses the trigger 622 of the return/stop switch
620. That is, when the trigger 622 of the return/stop switch 620 is
pressed by the pressing boss 530, the electric power being supplied
to the motor 610 is cut off. Accordingly, the rotating driving
shaft 611 and the pusher 500 start to rotate from a position where
the pressing boss 530 presses the trigger 622 and continue to
rotate until the pressing boss 530 presses the trigger 622 again.
Thus, when one pressing boss 530 is provided in the rotating plate
520 in the circumferential direction thereof as in the embodiment,
the pusher 500 makes one rotation and then stops all the time. If
two pressing bosses 530 are provided at equal intervals in the
circumferential direction thereof, the pusher 500 makes half a
rotation and then stops all the time.
[0212] The switch body 621 of the return/stop switch 620 is
installed outside the pusher 500 so as not to interfere with the
pusher. However, the switch body 621 is installed in a position
where the trigger 622 may interfere with the pressing boss 530.
[0213] Controlling a position where the pusher 500 stops rotating
with the return/stop switch 620 is advantageous in many aspects.
Rotating (one rotation in the embodiment) at a predetermined angle
all the time may be physically realized with a simple structure.
Additionally, as long as the controller 90 allows electric power to
be supplied to the motor 610 such that the pusher 500 rotates when
electric power is supplied again, even though the pusher 500 stops
rotating due to a power outage, and the like, the pusher 500
returns and exactly stops and is disposed back to its initial
position and pressing the trigger 622 of the return/stop switch
620.
[0214] The opening sensing switch 400 includes a switch body 410
fixed onto the fixing wall 151 of the opening sensing switch fixing
portion 150 provided below the hook accommodating space 180, and
the trigger 420 protruding upward from the switch body 410. The
trigger 420 has elasticity such that the trigger protrudes upward
when external force is not applied to the trigger. Accordingly,
when external force pressing the trigger 420 is removed, the
trigger 420 protrudes upward.
[0215] As described above, the pushing member 330 presses the
trigger 420 by means of the pressing force applied to the pushing
member 330 of the lever 300 by the latch 200 accommodated in the
hook accommodating space 180 in the state where the hook member 230
of the latch 200 is held by and fixed onto the inner inclined
surface 112. In the state where the latch 200 does not press the
pushing member 330, and the pushing member 330 alone presses
against the trigger 420, for the reason that the latch 200 is
released from the latch passage 110, and the like, the pushing
member 330 does not have sufficient force to press and activate the
trigger 420. That is, the force applied upward by the trigger 420
is weaker than the pressing force applied by the latch 200, but
stronger than the pressing force applied solely by the pushing
member 330.
[0216] The latch 200 may be provided on both sides of the door, and
a latch holder provided with an outer inclined surface 111 and an
inner inclined surface 112 as a lock for the latch may also be
disposed on both sides of an opening of a cavity opened and closed
by the door in the main body of the cooking appliance. Also, the
opening sensing switch 400 may be provided in both latch holders.
Thus, the controller may determine that the door of the cooking
appliance is open and may prevent the cooking appliance from
operating, as long as the triggers of both opening sensing switches
400 are not simultaneously pressed.
[0217] An automatic latch release structure including the lever,
the pusher, and the like according to the above-described
embodiment may be provided in any one of the both latch holders.
Accordingly, the opening sensing switch 400 in one latch holder may
be indirectly pressed by the lever 300 when the latch 200 is
accommodated and presses against the pushing member 330 of the
lever 300, and the opening sensing switch in the other latch holder
may be directly pressed by the latch when the latch is
accommodated.
[0218] Referring now to FIG. 5, in the state where the hook member
230 of the latch 200 is accommodated in the hook accommodating
space 180, i.e., the state where the door of the cooking appliance
is closed, the pushing member 330 of the lever 300 is pressed by
the hook member 230, which, in turn presses the trigger 420 of the
opening sensing switch 400. In this case, the lever 300 is rotated
most clockwise around the lever shaft supporter 122.
[0219] When the user inputs an instruction to release the hook
member 230 of the latch 200 from the hook accommodating space 180,
i.e., an instruction to open the door of the cooking appliance, the
motor 610 rotates, which rotates the pusher 500, as shown in FIG.
6. According to the embodiment, the pusher 500 rotates
counterclockwise although the rotational direction of the pusher is
not concerned. As the pusher 500 rotates, the lever 300 is pushed
by the pusher cam 540, which rotates counterclockwise around the
lever shaft supporter 122. Then the pushing member 330 is lifted
upward angularly, and the hook member 230 of the latch 200, which
was resting on the pushing member 330 is also lifted.
[0220] When the pusher 500 further rotates, the pusher cam 540
further pushes the effort arm 340 of the lever 300 to the rear end
until the pusher cam 540 has rotated sufficiently such that it no
longer contacts the effort arm 340. The pusher 500 continues to
rotate to the position in FIG. 7 where the pressing boss 530
presses the trigger 622 of the return/stop switch 620 and then
stops. The lever 300 then rotates clockwise around the lever shaft
supporter 122 by means of the return spring 630 and returns to the
initial position the lever has started from.
[0221] With reference to FIGS. 8 and 11, a process of automatically
opening the door of the cooking appliance having the latch holder
10 that operates as described above will be described.
[0222] The latch 200 used together with the latch holder 10 of the
present disclosure, as shown in FIG. 8, is installed so as to
swivel vertically and angularly about a horizontal pivot axis 210
and includes a latch bar 220 where elasticity is applied downward
via a spring (not shown) and the hook member 230 protrudes and
extends downward from the distal end of the latch bar 220.
[0223] The latch 200 has an upper inclined surface 221 in the upper
part of the distal end thereof, and the upper inclined surface 221
has a surface shape smoothly (e.g., linearly) inclined downward
toward the distal end of the latch. The upper inclined surface 221
is a surface slidably contacting the upper ceiling 113 of the latch
passage 110 when the latch 200 is moved upward and supported
forward by the lever 300, for example, when the door is prevented
from opening due to unexpected problems.
[0224] The hook member 230 includes a distal end flat surface 233
with a flat surface shape provided at the distal end thereof, and a
low distal end inclined surface 232 with a curved surface shape
provided in the lower part of the distal end flat surface 233.
Additionally, the hook member 230 includes a rear inclined surface
231 with a curved surface shape, contacted and held by an inner
inclined surface 112 of the latch passage 110, at the rear surface
thereof.
[0225] The latches 200 provided on the left and right of the door
may both have the shape described above.
[0226] In this embodiment, even though the lever 300 of the latch
holder 10 on one side of the door pushes the latch 200 upward and
forward, the latch on the other side of the door is not linked to
and swivels with the latch on the one side of the door with the
lever 300. However, the opening force of the door is exerted to the
other side of the door by means of the pushing force applied by the
lever 300 to the latch on the one side of the door. Accordingly,
the rear inclined surface 231 of the hook member 230 of the latch
200 on the other side of the door is released and escapes from the
other latch holder while riding on the inner inclined surface 112
of the other latch holder.
[0227] The curved surface shape of rear inclined surface 231
provides for manually opening the door. When the user pulls the
door forward, the latch 200 escapes from the latch passage 110
while the rear inclined surface 231 of the hook member 230 of the
latch 200 on respective both sides of the door ride on the inner
inclined surface 112 of the latch passage 110. The present
disclosure provides a device that includes a lever 300, a pusher
500 and a pusher driver 600 in a latch holder 10 on one side of the
main body and allows a latch 200 to automatically escape from a
passage for a latch. However, there are times when the door has to
be manually opened due to, for example, a power outage, a failure
of a cooking appliance, servicing, and the like. Accordingly, the
present disclosure includes a rear inclined surface 231 formed in a
hook member 230 of both latches 200 so as to manually open the
door, and an inner inclined surface 112 and an outer inclined
surface 111 provided in both the latch holders.
[0228] FIG. 8 illustrates the state where the hook member 230 of
the latch 200 is drawn into the hook accommodating space 180, and
the rear inclined surface 231 of the latch 200 is held by the inner
inclined surface 112, i.e., the state where the door is closed. In
the state where the door is closed, the lower surface of the hook
member 230 rests on the upper surface 334 of the pushing member 330
of the lever 200. The pushing member 330 presses the trigger 420 of
the opening sensing switch 400 by means of the force applied
downward by the hook member 230.
[0229] Latch holders 10 are installed on both sides of the main
body. If the door is normally closed, opening sensing switches 400
of the two latch holders 10 are both pressed. Accordingly, the
controller 90 of the cooking appliance may confirm that the door is
closed. When the user manipulates the control panel installed on
the front surface of the door, the cooking appliance may start to
cook.
[0230] When the user inputs an instruction to open the door to the
control panel such as a display, a touch panel, and the like
installed on the front surface of the door, the door may
automatically open. In order for the door to automatically open,
one latch 200 of the door, locked by the latch holder 10 on one
side of the main body, has to be released, and, also, the other
latch of the door, locked by the latch holder 10 on the other side
of the main body has to be released.
[0231] To this end, the controller 90 rotates the motor 610. When
the motor 610 rotates, the pusher 500 rotates, and the pusher cam
540 rotates and pushes the effort arm 340 of the lever 300
backward, as in FIG. 9. Accordingly, the lever 300 rotates
counterclockwise about the shaft 310, and the pushing member 330 at
the front of the lever 300 moves upward and forward. According to
the embodiment, when the lever 300 rotates, the pushing member 330
swivels forward and upward because the shaft 310 of the lever 300
is placed further backward and upward than the pushing member
330.
[0232] In this case, the distance between the shaft 310 and the
effort arm 340 is longer than the distance between the shaft 310
and the pushing member 330. Thus, the force of the motor 610 is
increased and delivered to the pushing member 330.
[0233] The pushing member 330 itself slightly rotates because the
pushing member 330 moves upward while revolving around the shaft
310. Thus, the push-up inclined surface 333 of the pushing member
330 moves the latch 200 forward and upward while contacting the low
distal end inclined surface 232 of the latch 200. An outer
insertion member 332 of the pushing member 330 is preferably made
from a material having lubricativity and high wear resistance so as
to allow the push-up inclined surface 333 to contact the low distal
end inclined surface 232 and smoothly move. The movement is
sensitive to the path of the lever and latch. Accordingly, when the
pushing member 330 is made from a material causing friction or
having low wear resistance, the latch 200 may damage the pushing
member 330, and the pushing member 330 may not move the latch 200
upward.
[0234] When the pushing member 330 pushes the latch 200 forward and
moves the same upward while moving upward, the trigger 420 of the
opening sensing switch 400 is released from the press of the
pushing member 330.
[0235] Additionally, the hook member 230 of the latch 200 passes
over the inner inclined surface 112 and moves toward the outer
inclined surface 111.
[0236] As the pushing member 330 continues to move upward, the
push-end part 336 that is the lowest edge of the push-up inclined
surface 333 finally pushes the hook member 230 over the inner
inclined surface 112 and the latch 200 swivels downward by
elasticity of the latch 200, as in FIG. 11.
[0237] The force of the latch 200 swiveling downward is converted
as force in the horizontal direction while the latch 200 slides
down the outer inclined surface 111, and the door is opened further
forward.
[0238] When there is an obstacle, and the like blocking the path
where the door opens, a large amount of the force of opening the
door may be required in the direction in which the door opens. In
this case, even though the pushing member 330 moves upward, the
latch 200 may only move upward with the pushing member 330 and the
latch 200 may not move forward.
[0239] Even in this case, the upper inclined surface 221 of the
latch 200 contacts the upper ceiling 113 of the latch passage 110,
as in FIG. 10. When the pushing member 330 moves further upward in
the state where the latch 200 contacts the upper ceiling 113, the
push-end part 336 that is the lowest edge of the push-up inclined
surface 333 finally pushes the lever 300 farthest away, as in FIG.
10. Then the upper inclined surface 221 of the latch 200 is pushed
outward while contacting the upper ceiling 113 of the latch passage
110 and may move.
[0240] The upper inclined surface 221 may entirely contact the
upper ceiling 113 such that the upper inclined surface 221 smoothly
contacts the upper ceiling 113 and slides. To this end, when the
latch 200 is lifted, the upper inclined surface 221 contacting the
upper ceiling 113 may be approximately horizontal.
[0241] If the upper inclined surface 221 does not contact the
surface of the upper ceiling 113 entirely but is inclined slightly
to one side, the latch is not naturally drawn unlike the latch of
the upper inclined surface 221 that is horizontal.
[0242] According to the embodiment, when a small amount of the
opening force of the door is required, the latch 200 may move in
order of FIG. 8, FIG. 9 and FIG. 11 and then may escape from the
latch holder 10. Even when a large amount of the opening force of
the door is required, the latch 200 may move in order of FIG. 8,
FIG. 9, FIG. 10 and FIG. 11 and then may escape from the latch
holder 10. That is, in any case, the door may automatically open.
Also, even though there is a deviation in opening force applied to
the door for an automatic opening due to a deviation in forces
applied by the spring 823 of the hinge module 800 (see FIG. 14) in
the direction in which the door is closed depending on products,
the latch holder 10 described above may definitively unlock the
latch.
[0243] As in FIG. 11, since the force of the latch 200, reaching a
position where the latch is unlocked by the lever 300 and swiveling
downward, is converted in the horizontal direction while the latch
passes the outer inclined surface 111, the door opens further
forward and smoothly opens.
[0244] With reference to FIG. 18, when the lever 300 rotates around
the shaft hole 310, the upper end of the push-up inclined surface
333 starts to move the latch 200 upward while contacting the hook
member 230 of the latch 200 and moving. Next, as the lever 300
rotates further counterclockwise, the position of the hook member
230 contacting push-up inclined surface 333 moves to the lower part
of the push-up inclined surface 333. When the lever rotates further
counterclockwise and the push-end part 336 moves to a height the
same as that of the shaft hole 310, the lever 300 has pushed the
hook member 230 farthest away from the pushing member 330. That is,
as the lever 300 rotates counterclockwise, the push-up inclined
surface 333 lifts the hook member 230 and moves the hook member 230
upward in the direction of the arrow in FIG. 18 while pushing the
hook member 230 towards and onto the push-end part 336.
[0245] When the push-end part 336 is or above a height the same as
that of the shaft hole 310, the hook member 230 is released and the
latch 200 escapes from the path of the pushing member 330. Then the
latch 200 falls downward due to elasticity of the latch, as in FIG.
11. That is, the latch 200 contacting the upper ceiling 113 moves
downward again. In this case, the latch 200 is on the outer
inclined surface 111 because the latch has been pushed further
forward from the end of the arrow in FIG. 18. That is, the hook
member 230 of the latch 200 is no longer held by the inner inclined
surface 112, and the lower part of the hook member 230 moves
downward, sliding on the outer inclined surface 111, as the door
opens.
[0246] As the pushing member 330 moves upward to the height the
same as that of the shaft hole 310, the upper end of the push-up
inclined surface 333 moves forward from an initial position by m
because the pushing member 330 is disposed in the front lower part
of the shaft hole 310. According to the embodiment, the low distal
end inclined surface 232 of the latch 200 contacts the push-up
inclined surface 333 and moves from the upper end of the push-up
inclined surface to the lower end thereof. Thus, the latch 200 is
pushed further forward by n.
[0247] FIG. 12 illustrates an opening angle (a1) of the door caused
by the latch 200 being pushed outward. The door automatically opens
by means of self-weight as the door is now not perpendicular to the
front of the cooking appliance but is opened and inclined by an
angle of a1, as illustrated. However, if a speed at which the door
automatically opens by means of self-weight is not controlled, the
speed may increase while the door opens, and the door might slam
open. According to the embodiment, when the door 720 opens by a
predetermined angle (a2), a damper starts to operate so as to
slowly open the door at controlled speed to a final opening angle
(a3), thereby preventing damage to the door and a hinge module 800
of the door and providing a comfortable feeling to the user when
the user sees the door automatically opening and controllably.
[0248] When the user touches a touch panel, and the like in the
upper part of the front surface of a door and inputs an instruction
to open the door, the latch holder 10 operates in order of FIGS. 5
to 7. Accordingly, the latch 200 is released from the latch holder
10, and the door is pushed by a predetermined angle (a1) in order
of FIGS. 8 to 11.
[0249] The predetermined angle (a1) may be set to the extent that
the door automatically opens by means of self-weight. The angle
(a1) may range from 1.degree. to 7.degree. and, preferably,
1.degree. to 30.degree..
[0250] Referring to FIGS. 13 and 14, the hinge module 800 connects
the main body 710 and the door 720. A door bar 840 of the hinge
module is fixed to the door 720, and a housing 810 of the hinge
module is fixed to the main body 710. The door bar 840 and housing
810 rotate around a rotational axis member 814.
[0251] As the door bar 840 rotates around the housing 810, damping
force is delivered to the door bar 840.
[0252] An inner link housing 830 capable of moving in a lengthwise
direction of the housing is provided in the housing 810. The distal
end of the inner link housing 830 is hinge-coupled to the door bar
840 by a door bar connecting hinge 831. Accordingly, when the door
720 (door bar 840) opens, the door bar connecting hinge 831 moves
forward while revolving around the rotational axis member 814
because the door bar connecting hinge 831 is eccentrically placed
from the rotational axis member 814 by a distance of r.
Accordingly, the inner link housing 830 moves forward in the
housing 810.
[0253] A maximum opening angle (a3) of the door or the door bar is
90.degree. because the door 720 or the door bar 840 opens from the
position where the door or the door bar perpendicularly stands to
the position where the door or the door bar lies forward and
horizontally. Accordingly, the connecting hinge 831 revolves
90.degree. around the rotational axis member 814. The inner link
housing 830 moves forward by a horizontal distance (d3) resulting
from the 90 degree revolving of the rotational axis member 814.
[0254] A spring insert pin 820 is installed at the rear of the
inner link housing 830. The spring insert pin 820 is connected with
the rear of the inner link housing 830 by an inner housing link pin
822. Both ends of the inner housing link pin 822 are fitted into a
link pin guide slot 815 in the housing 810. The link pin guide slot
815 has an elongated hole shape extending in the lengthwise
direction of the housing 810.
[0255] The spring insert pin 820 is inserted into a compression
coil spring 823 that has excellent elasticity and is already in the
state of being compressed. The spring insert pin 820 may penetrate
a spring stopper plate 811 fixed to the housing 810 and slide in
the lengthwise direction of the housing 810. However, the distal
end of the compression coil spring 823 is held by the spring
stopper plate 811 of the housing 810. A spring stopper plate
support pin 812 for additionally supporting the spring stopper
plate 811 may be further installed in the housing 810 so as to
support the spring stopper plate 811 from the force applied by the
compression coil spring 823.
[0256] A spring support pin 821 for fixing the rear end of the
spring 823 is installed at the rear end of the spring insert pin
820. The spring support pin 821 does not interfere with the housing
810.
[0257] When the door bar 840 opens, the inner link housing 830 and
the spring insert pin 820 may move forward while the inner housing
link pin 822 is guided by the guide slot 815 of the housing 810.
Accordingly, the elasticity of the spring 823 becomes greater while
the spring is compressed between the spring stopper plate 811 and
the spring support pin 821. A length of a compressed spring 823
corresponds to a distance (d3) horizontally moved by the rotational
axis member 814. When the opening angle of the door is small,
elasticity of the spring 823 is low while when the opening angle of
the door increases, elasticity of the spring 823 increases. The
elasticity is applied against the direction in which the door
opens.
[0258] Force applied by the spring 823 in the direction in which
the door is closed becomes greater from opening angle a1 to opening
angle a3 of the door. The force applied by the spring 823 at
opening angle a1 of the door is smaller than the force that the
door automatically opens by means of the self-weight (opening
force) at opening angle a1. Thus, the door pushed by the lever 300
to the opening angle a1 automatically opens.
[0259] A damper 850 is installed in the inner link housing 830. A
piston 851 of the damper 850 is supported by a damper presser 832
integrally fixed to the inner link housing 830. The piston 851 is
inserted into a cylinder 852. A slot 853 into which a damper
support pin 813 fixed to the housing 810 is fitted is provided in
the upper part of the cylinder 852. The cylinder 852 may move
forward and backward as far as a length of the slot 853. FIG. 14
illustrates positions of the slot 853 of the damper 850 and the
damper support pin 813 of the housing 810 in the state where the
door is closed.
[0260] As the door opens and swivels by a predetermined angle (a2),
the inner link housing 830 moves by d2 forward and horizontally,
and the damper 850 moves together with the inner link housing while
being pushed forward by the damper presser 832 of the inner link
housing 830. When the damper is pushed forward, the damper presser
832 pushes the piston 851 of the damper 850 forward. However, the
slot 853 of the cylinder 852 is not yet held by the damper support
pin 813. Accordingly, the damper 850 moves forward together with
the inner link housing 830 but does not generate any damping
force.
[0261] At the moment when the opening angle of the door exceeds a2,
the slot 853 of the damper 850 moving forward is held by the damper
support pin 813, and then the damper 850 starts to be compressed as
the piston 851 presses into the cylinder 852. The damping force,
generated when the damper 850 is compressed, damps the opening
force of the door in a range of opening angles of a2 to a3, thereby
controlling the opening force of the door.
[0262] A maximum damping distance (Lmax) of the damper 850, i.e., a
maximum stroke for generating damping force while the damper is
compressed, is set to be greater than or equal to a distance
(d3-d2) moved by the inner link housing 830 while damping force is
applied to the door.
[0263] Specifically, while a closed door opens to a2, the door bar
connecting hinge 831 also rotates by a2. Accordingly, the inner
link housing 830 and the spring insert pin 820 move forward by d2.
While the inner link housing 830 and the spring insert pin 820 move
by d2, the slot 853 of the damper 850 rides on the damper support
pin 813 and moves. Thus, the damper is not pressed. That is,
elasticity of the spring 823 is applied against the direction where
the opening force of the door is applied in a range of opening
angles of the door of 0 to a2 so as to lower the opening speed of
the door.
[0264] While a closed door opens to a3, the door bar connecting
hinge 831 rotates by a3, and the inner link housing 830 and the
spring insert pin 820 move forward by d3. Accordingly, the spring
823 is compressed by d3. That is, elasticity of the spring 823 is
applied against the direction where the opening force of the door
is applied in a range of opening angles of the door of 0 to a3 so
as to lower the opening speed of the door.
[0265] The maximum opening angle (a3) may be controlled by the link
pin guide slot 815 of the housing 810 controlling a distance at
which the inner housing link pin 822 slides.
[0266] The damper 850 may continue to damp the opening force of the
door, for instance, from the opening angle of the door, which is
about 30.degree. to 40.degree. to the opening angle of the door,
which is about 90.degree.. Thus, the door may open to an initial
opening angle (a1) by a latch holder 10, then open by means of the
self-weight at an accelerated speed and when the door opens to a2
(about 30.degree. to 40.degree.), is slowed by means of the damping
force of the damper. The door opening method ensures a comfortable
feeling for the user.
[0267] If damping starts too fast while the door is opening, the
door opens too slowly. This makes the user feel uncomfortable.
Conversely, if damping of the door starts too late, the door opens
too fast until the door has opened to a considerable extent. This
can make the user feel uncomfortable or hit against the door.
[0268] A damping start angle (a2) at which the damper 850 starts to
damp the opening force of the door is preferably
35.degree..+-.5.degree. in this embodiment.
[0269] The damping force may continue until the door completely
opens to 90.degree. or until the door opens to 85.degree. that is
5.degree. less than 90.degree.. If the damping force is applied
even in a section where the door completely opens, the door might
open to 88.degree. to 89.degree. that is 1.degree. to 2.degree.
less than 90.degree.. Thus, in one embodiment, it can be considered
that damping force is not applied at an angle of greater than
85.degree..
[0270] The damping start angle (a2) is set to be greater than a
forcible opening angle (a1). Additionally, a section between the
forcible opening angle (a1) and damping start angle (a2), i.e., a
section from 1-7.degree. to 30-40.degree., is a section where the
opening force of the door is not damped by any damper 850 and where
the door automatically opens by means of the self-weight. The
elasticity of the spring 823 may be applied against the direction
in which the door opens in this section. Thus, the acceleration of
the door may be reduced or prevented in the section where the door
automatically opens by means of the self-weight.
[0271] Applying the above-described automatic door opening
structure makes the user feel less uncomfortable and enhances
emotional quality of a product. Further, a handle protruding from
the door may be removed, thereby providing aesthetic qualities to a
cooking appliance, in particular, a built-in cooking appliance.
[0272] A damper for the door of a building is a mechanical element
that prevents the door from slamming shut while a spring applies
force in the direction where the door is closed. The elasticity of
the spring applied in the direction where the door is closed is
maximized when the door opens to a maximum angle and is gradually
minimized as the door is gradually closed. When a damper providing
a proper level of damping force is installed, as the door is
gradually closed, the elasticity of the spring applied in the
direction where the door is closed is gradually minimized. Thus,
the damping force of the damper significantly affects the speed at
which the door is closed, and the speed at which the door is closed
is gradually lowered.
[0273] On the contrary, when a damper is closed while a door with a
pull-down type opening structure as in the present disclosure
opens, the opening force of the door consists of moment by means of
the self-weight of the door. Unlike building doors, an automatic
door opening system of the present disclosure is a system in which
the opening force increases as damping performed by a damper
proceeds.
[0274] Referring to FIG. 17, the opening force applied by the
self-weight of a door may be defined as a sign function of the
opening angle of the door. On the contrary, the force of preventing
an opening, applied by a spring 823, may be defined as a linear
function of a spring constant. The damping force of the damper is
proportional to the speed of damped movement. However, according to
the present disclosure, the damping force of the damper may be
expressed as a constant because the door is controlled so as to
fall nearly at a fixed speed.
[0275] That is, the damping force is constant regardless of the
opening angle of the door. Accordingly, the damping coefficient of
a damper has to be very large so as to provide enough damping force
against a large opening force applied at the moment when the door
is close to opening. However, when the damping coefficient of a
damper is large, an initial opening is performed very slowly or is
not smoothly performed because the damping force against the
opening force increases in the step of the initial opening. That
is, when the damping force (Fd1) of a damper is too large, the
initial opening is not smoothly performed, while when the damping
force (Fd1) of a damper is small, the damping force does not
withstand the opening force that increases in accordance with an
increase in an opening angle.
[0276] Accordingly, the present disclosure presents a way of
designing different hinge modules 800 provided respectively in two
hinges of a pull-down door. For instance, as in FIG. 14, a damper
850 in one hinge module 800 starts damping with a first damping
force (Fd1) at a damping start angle (a2) while as in FIGS. 15 and
16, a damper 850 in the other hinge module 800 starts damping with
a second damping force (Fd2) at an additional damping start angle
(a2') following the damping start angle (a2).
[0277] Accordingly, enough damping force (Fd1+Fd2) to damp the
opening force increased in accordance with an increase in the
opening angle is applied at an additional damping start angle
(a2'). As a result, an increased opening force too large for one
damper to withstand may be damped.
[0278] The additional damping start angle (a2') may be about
60.degree. to 80.degree., i.e. 70.degree..+-.10.degree..
[0279] Referring to FIGS. 14 and 15, a length (d2') of a slot 853
of a cylinder 852 of a damper 850 of the hinge module 800 that
starts damping at an additional damping start angle (a2') in FIG.
15 may be longer than that of a length (d2) of a slot 853 of a
cylinder 852 of a damper of the hinge module 800 that starts
damping at a damping start angle (a2) in FIG. 14. A distance (r)
between a rotational axis member 814 and a door bar connecting
hinge 831 of the hinge module 800 in FIG. 14 is the same as that of
the hinge module 800 in FIG. 15. Accordingly, distances (d3) moved
by inner link housings 830 are the same. However, distances (d2,
d2') moved by the inner link housings 830 are different in the
state where the damping force of the damper is not applied because
of different lengths of the slots 853.
[0280] Additionally, a distance (r) between the rotational axis
member 814 and the door bar connecting hinge 831 of the hinge
module in FIG. 14 is the same as that of the hinge module in FIG.
15. Thus, damping forces generated at the same opening angle are
the same. That is, damping force Fd1 and damping force Fd2 in FIG.
17 may be substantially the same.
[0281] Referring to FIGS. 14 and 16, a distance (r') between a
rotational axis member 814 and a door bar connecting hinge 831 of
the hinge module 800 that starts damping at an additional damping
start angle (a2') in FIG. 16 may be shorter than that of the hinge
module 800 that starts damping at a damping start angle (a2) in
FIG. 14. That is, when a distance (r') between the rotational axis
member 814 and the door bar connecting hinge 831 becomes shorter, a
distance (d3') moved forward by an inner link housing 830 until the
door completely opens becomes shorter. That is, the distance (d3')
moved by an inner link housing 830 at the same opening angle is
shortened as much as a shortened distance (r') between the
rotational axis member 814 and the door bar connecting hinge
831.
[0282] Distances (d2) moved by inner link housings 830 to generate
damping force are the same because lengths (d2) of the slots 853 of
the cylinders 852 of the dampers 850 of two hinge modules 800 in
FIGS. 14 and 16 are the same. However, there is a difference in the
distances between the rotational axis members 814 and the door bar
connecting hinges 831. Accordingly, swivel angles of the door 720
or the door bar 840 are different so as to move the inner link
housing 830 by the same distance (d2). That is, in the hinge module
800 of FIG. 14, an opening angle of the door that has to swivel so
as to move the inner link housing 830 by d2 is a2 while in the
hinge module 800 of FIG. 16, an opening angle of the door that has
to swivel so as to move the inner link housing 830 by d2 is
a2'.
[0283] Meanwhile, a distance (r') between the rotational axis
member 814 and the door bar connecting hinge 831 of the hinge
module in FIG. 16 is shorter than that of the hinge module in FIG.
14. Accordingly, a damping distance of the damper in FIG. 16 is
shorter than that of the damper in FIG. 14 at the same opening
angle, and the damping force of the damper in FIG. 16 is smaller
than that of the damper in FIG. 14. That is, the damping force
generated when the hinge module in FIG. 16 swivels at the same
opening angle is smaller than the damping force generated when the
hinge module in FIG. 14 swivels at the same opening angle. To put
it another way, in FIG. 17, Fd2 may be smaller than Fd1.
[0284] A damping force against an increasing opening force of a
door may be supplied by means of a difference in the damping start
angles of the hinge modules in both hinges of a pull-down door, as
illustrated in the relationship between the hinge modules of FIGS.
14 and 15, and the relationship between the hinge modules of FIGS.
14 and 16.
[0285] The difference in damping start angles may be made by means
of a difference in lengths (d2, d2') of slots 853 of cylinders or a
difference in distances (r, r') between a rotational axis member
814 and a door bar connecting hinge 831 in the same hinge module
structure, and the magnitude of damping forces (Fd1, Fd2) provided
at the two damping start angles (a2, a2') may be adjusted by means
of a difference in distances (r, r') between door bar connecting
hinges 831.
[0286] Thus, even though opening forces are different based on the
self-weight or size of doors, an optimum damping force against an
increasing opening force of the door may be provided by means of a
difference in lengths (d2, d2') of the slots 853 of the cylinders
of the hinge modules respectively on both sides of the door or a
difference in distances (r, r') between a rotational axis member
814 and a door bar connecting hinge 831, with no need to design a
new hinge module.
[0287] In addition to different damping forces and damping start
angles, the spring constant of a spring 823 (gradient in FIG. 17)
and a degree of the initial compression of the spring (initial
value in the graph of elasticity in FIG. 17) may be adjusted such
that a door may open at controlled speed against the opening force
of the door. The spring constant and the degree of the initial
compression of the spring are preferably less than or equal to the
opening force generated by means of the self-weight of a door at an
initial opening angle (a1; angle at which a door opens after a
latch holder pushes a latch) (resistance against opening force
generated by a damper and a spring by adjusting damping force and
spring constant is designated by the two dot chain line in FIG.
17).
[0288] Below, a control method for an automatic opening of a door
according to an embodiment will be described with reference to
FIGS. 19 to 21. A controller 90 may perform the control method for
the automatic opening of a door.
[0289] According to the embodiment, a door automatically opens by
means of one rotation of a motor 610. While a motor makes one
rotation, a pusher 500 rotates. Then, a pusher cam 540
eccentrically disposed in a pusher pushes a lever 300 and returns
to an initial position. The lever 300 pushes a latch 200 forward
and upward with the pusher cam 540. Then, the door automatically
opens.
[0290] According to the structure of the above-described latch
holder 10, the latch holder may be in four states in the state in
which the cooking appliance according to the embodiment is powered
off.
[0291] First, as in FIG. 8, the door is closed, the latch 200 is
held in the latch holder 10, the lever 300 moves clockwise and is
disposed at the end in a range of the swivel of the lever 300 by
means of the pressing force applied downward by the latch 200, and
the pusher 500 is in the correct position where the pusher 500
presses a return/stop switch 620.
[0292] Second, the door is open, and the pusher 500 is arranged in
the correct position and presses the return/stop switch 620, as in
FIG. 7.
[0293] Third, the pusher 500 stops rotating due to a power outage,
and, as in FIG. 6, is not in the position where the pusher 500
presses the return/stop switch, and a pushing member 330 of the
lever 300 is lifted, and the door is open. In the state of FIG. 6,
the latch 200 may not come into the latch holder 10, and,
accordingly, the door may not be closed because the pushing member
330 of the lever 300 blocks the inlet of the latch holder 10.
[0294] Fourth, the pushing member 330 slightly moves downward
without blocking the inlet of a latch holder 10, and a pressing
boss 530 of the pusher is in an initial state where the pressing
boss does not press the return/stop switch 620. This state is
between the state in FIG. 6 and the state in FIG. 7. In this state,
the latch 200 may come into the latch holder. When the latch comes
into the latch holder, the load of the latch presses the lever, and
the lever is forcibly rotated and moves the pusher 500 while
rotating. Accordingly, this state turns into the state in FIG.
8.
[0295] According to the embodiment, the pusher 500 makes one
rotation so as to open the door. The pusher 500 starts to rotate in
the correct position, i.e., the position in FIG. 8 and makes one
rotation. When the pusher 500 makes one rotation, the pushing
member 330 of the lever 300 makes exactly one upward movement, and,
accordingly, the door automatically opens. If the pusher 500 starts
to rotate so as to open the door in the state where the pusher 500
is placed in the position in FIG. 6, which is not in the correct
position, credibility of an automatic opening of a door may not be
ensured.
[0296] In this embodiment, when a cooking appliance starts to
operate, for instance, when the cooking appliance is plugged into
the socket, or the user presses the power button of the cooking
appliance so as to turn on the cooking appliance, the controller 90
controls operation of the pusher 500 such that the pusher is in the
correct position.
[0297] As in FIG. 7 or 8, when the pusher 500 has already pressed
the return/stop switch 620 and the return/stop switch is on, the
control 90 may confirm that the pusher has already been placed in
the correct position. Thus, there is no need to arrange the pusher
500 in the correct position. If the pusher 500 is rotated so as to
arrange the pusher in the correct position in the state where the
door is closed, as in FIG.8, the closed door might open.
[0298] In this case, a wait state is maintained until the user
inputs an instruction to open the door.
[0299] When the pusher 500 is not in the correct position where the
pusher has pressed the return/stop switch 620, as in FIG. 6, the
door is open. Thus, even though the pusher 500 rotates so as to be
arranged in the correct position, the closed door does not
open.
[0300] That is, when the cooking appliance starts to operate (when
electric power is supplied to the cooking appliance or when the
power button of the cooking appliance is turned on), if the
controller 90 senses that the return/stop switch is off, that is, a
return/stop switch is not pressed, the controller 90 arranges the
pusher 500 in the correct position as in FIG. 20.
[0301] Below, a step of arranging a pusher to an initial correct
position by supplying power to a motor is described. Preferably,
uninterrupted power (possibly, alternating power) is supplied to a
motor so as to rotate the motor evenly, instead of electric power
(pulse power, and the like) for allowing a motor to rotate
differently.
[0302] Referring now to FIG. 20, when electric power is supplied to
the motor S201, the motor rotates, and the pusher 500 rotates and
reaches to the position in FIG. 7, The pusher 500 presses the
return/stop switch 620, and the power being supplied to the motor
is cut off. In this instance, the pusher is arranged in the correct
position.
[0303] The controller confirms whether the return/stop switch is
pressed after a period of time long enough for the motor to make
one rotation (t.sub.0) S202. When the return/stop switch is pressed
S203, the motor is normally operating, the return/stop switch is
normally operating S204, and the pusher 500 is arranged in the
initial correct position. In this case, a wait state is maintained
until the user inputs an instruction to open the door as described
above. See FIG. 19.
[0304] If the return/stop switch is not pressed even after the
period of time (t.sub.0) S203, the motor or the return/stop switch
is operating incorrectly S205. As described above, in the state of
FIG. 6, the door may not be closed. Accordingly, an opening sensing
switch 400 is off, and the door is open. Thus, it is difficult to
confirm whether the motor normally operates by confirming whether
the door is open by means of the movement of the motor. Then the
controller may generate a fourth error signal of a problem with the
motor or the return/stop switch S206. Additionally, the controller
may finish operation of the cooking appliance as a follow-up.
[0305] The state where the user's instruction to open the door is
waited for after the pusher 500 is arranged in the correct position
is the same as the state in FIG. 7 or FIG. 8. Even though an
instruction to open the door is inputted, and the pusher 500 makes
one rotation in the state of FIG. 7, i.e., in the state where the
door is open, the product operates correctly.
[0306] Certainly, even though the user inputs an instruction to
open the door in the state of FIG. 7, i.e., the state where the
return/stop switch is pressed while the opening sensing switch is
not pressed, electric power may not be supplied to the motor.
However, noteworthy is that there is no need to react to the
instruction to open the door based on each of the states in FIG. 7
and in FIG. 8 for simplifying control algorithm.
[0307] The door according to the embodiment may be opened
automatically and manually. With this in mind, a control method for
an automatic opening of the door will be better understood.
[0308] Referring now to FIG. 19, shortly after electric power is
supplied to the motor with the user's instruction to open the door
S101, S102, the controller 90 confirms whether the return/stop
switch is turned off S103. When the return/stop switch is turned
off, the motor has started to rotate normally S104.
[0309] After a period of time long enough for the motor to make one
rotation (t.sub.0) S105, i.e., the pusher 500 makes one rotation,
the controller confirms that the opening sensing switch is off
S106. In a state the same as the state of FIG. 8, the opening
sensing switch that was on as the door opened is turned off, while
in a state the same as the state of FIG. 7, the opening sensing
switch is kept off. Thus, in any case, when the opening sensing
switch is off after the predetermined period of time, the latch has
normally escaped from the latch holder S107.
[0310] Next, after a period of time long enough for the motor to
make one rotation (t.sub.0), the controller 90 confirms that the
return/stop switch is on again S108. If the motor has rotated and
returned to the initial position normally, the return/stop switch
is pressed. Accordingly, the return/stop switch is normally
operating S109. Additionally, when the return/stop switch is
pressed, electric power being supplied to the motor is immediately
cut off. Thus, the pusher is placed in the initial correct
position.
[0311] In this case, the controller is in the state of waiting for
the user's instruction to open the door again.
[0312] When the return/stop switch is not turned on even after a
period of time long enough for the motor to make one rotation, the
motor or the return/stop is operating incorrectly S110.
[0313] If the return/stop switch is not turned on after the
predetermined period of time while the opening sensing switch that
was on is turned off (that is, the door has opened), during the
predetermined period of time, the return/stop switch is operating
incorrectly. In this case, the controller 90 may generate a second
error signal of a problem with the return/stop switch and cut off
the power being supplied to the motor S111.
[0314] It might be difficult to confirm which of the motor and the
return/stop switch is operating incorrectly when the opening
sensing switch is kept off during the predetermined period of time
in the state where the door is open. In this case, the return/stop
switch that was on is turned off when electric power started to be
supplied to the motor. Thus, the return/stop switch is likely to
operate incorrectly rather than the motor. Accordingly, the
controller 90 may generate a second error signal of a problem with
the return/stop switch and cut off the power being supplied to the
motor.
[0315] That is, the controller 90 may confirm a problem with the
return/stop switch and generate a second error signal when the
return/stop switch is not turned on in any case.
[0316] Meanwhile, there are times when the opening sensing switch
is on following a period of time long enough for the motor to make
one rotation (t.sub.0) after electric power is supplied to the
motor with the user's instruction to open the door, and the
return/stop switch is turned off. In this case, the door might be
prevented from opening by an obstacle placed in the direction where
the door opens, or by the latch incorrectly held by the latch
holder, S112 while the motor is normally rotating. Then the
controller 90 may generate a first error signal of a problem with
the operation of the latch and cut off the power being supplied to
the motor S113.
[0317] When the return/stop switch is not turned off even after
electric power has been supplied to the motor with an instruction
to open the door input by the user, the step of generating an error
signal as in FIG. 20 may be required. In this case, there must be a
problem with any one of the motor and the return/stop switch.
Incorrect operation of any one of the motor and the return/stop
switch may be confirmed using additional signals.
[0318] Referring to FIG. 21, incorrect operation of any one of the
motor and the return/stop switch may be confirmed on the basis of
whether the door opens. The opening sensing switch was on, that is,
the door was closed when electric power was supplied to the motor
S211, and after a predetermined period of time S212, the opening
sensing switch is turned off S213. In this case, the door is open.
Thus, the motor is operating correctly S214. Accordingly, the
controller 90 may confirm that the return/stop switch is operating
incorrectly, generate a second error signal S215, cut off the
electric power being supplied to the motor and then finish
operation of the cooking appliance.
[0319] On the contrary, the opening sensing switch was on S213,
that is, the door was closed when electric power was supplied to
the motor, and, even after a predetermined period of time, the
opening sensing switch is kept on, the door is still closed. In
this case, the motor is operating incorrectly S214. Accordingly,
the controller 90 may confirm that the motor is operating
incorrectly S216, generate a third error signal S217, cut off the
power being supplied to the motor and then finish operation of the
cooking appliance.
[0320] However, when the opening sensing switch was off S211, that
is, the door was open, from the moment when electric power was
supplied to the motor, the controller 90 may not confirm whether
the motor operates correctly through the opening sensing switch
S218. In this case, the controller 90 may generate a fourth error
signal of a problem with any one of the motor and the return/stop
switch S219, cut off power being supplied to the motor and finish
control.
[0321] According to the control method of the embodiment, regular
electric power is supplied to a motor with no need to generate
another type of electric power and supply the same to a motor in
addition to usual uninterrupted AC power supplied to a cooking
appliance.
[0322] Additionally, signals from a return/stop switch for
determining where the motor stops and conventional opening sensing
switch for confirming whether the door opens are used to monitor
whether the automatic opening structure normally operates without a
sensor for sensing whether the motor operates.
[0323] FIG. 22 is block diagram of an electronic system to
implement an automatic opening structure and the control method in
FIGS. 19 to 21 according to an embodiment of the invention.
[0324] The electronic system includes, but not limited to, a
controller 90, an input device 110, such as a touch panel, and a
display 100. The display 100 may display time, various operation
status of the home appliance, and the like. The input device 110
may be used to input instructions pertaining to the operation of
the home appliance and the like. The controller 90 receives various
signals and instructions and controls the home appliance based on
the received signals and instructions. For instance, the controller
90 may receive instructions from the input device 110. The
controller 90 may receive signals from the opening sensing switch
400 and the return/stop switch 620. The controller 90 may control
the pusher driver 600 including the motor 610 to drive the pusher
500, which in turn lifts the lever 300. The actions of the
controller 90 above may be to operate an automatic door opening
function.
[0325] The controller may be a microprocessor, specific integrated
circuits (ASICs), digital signal processors (DSPs), digital signal
processing devices (DSPDs), programmable logic devices (PLDs),
field programmable gate arrays (FPGAs), and the like.
[0326] The present disclosure has been described with reference to
the attached drawings. However, it will be apparent that the
present disclosure should not be construed as being limited to the
implementations and drawings and that various modifications and
changes may be made by one having ordinary skill in the art within
the scope of the technical spirit of the invention. Further, even
though effects of the components of the invention are not
explicitly described, expected effects of the components should be
included in the scope of the invention.
* * * * *