Bleaching and dyeing; fluid treatment and chemical modification – Fluid treatment – Manipulation of liquid
Reexamination Certificate
1999-07-13
2001-09-25
Stinson, Frankie L. (Department: 1746)
Bleaching and dyeing; fluid treatment and chemical modification
Fluid treatment
Manipulation of liquid
C008S159000, C068S012050, C068S012060, C068S012210
Reexamination Certificate
active
06292966
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for sensing a water level and vibration of a washtub for a washing machine based the amount of a laundry, and in particular, to a method and apparatus for accurately sensing a water level and vibration by detecting an abnormal vibration caused by an inclination of the laundry during a dehydration process of a washing control mode as a LC resonant frequency for thereby optimizing a washing control operation and implementing an accurate detection of a water level and vibration of a washing machine.
2. Description of the Background Art
Generally, a washing machine is designed to detect the amount of a laundry in a washtub. When the amount of the laundry is detected, the water level, the amount of a detergent, and the entire washing time are determined based on the thusly detected amount of the laundry.
Based upon the total washing time required, the washing machine executes a washing operation in which the water within the washtub swirls based on the operation of a pulsator to form a frictional force against the laundry for thereby washing the laundry.
After the washing operation, the washing machine discharges the polluted water to the outside of the washtub and then execute a rinsing operation in which a fresh water is supplied into the washtub to rinse the laundry by the preset number of times.
After the rinsing operation, the washing machine discharges the water to the outside of the washtub and then executes a dehydration operation in which an induction motor rotates at a certain high speed for thereby dehydrating the laundry based on a centrifugal separation force.
In the washing operation control of the washing machine, at an initial washing stage, the washing machine opens a water supply valve to receive a certain amount of water in accordance with the amount of the laundry within the washtub, until the water level reaches a set water level. At this time, as a water level sensing method, there is known a sensing method in which a LC resonant frequency is varied based on the pressure of water supplied within the washtub.
By way of example, if the pressure of water supplied within the washtub is varied, the LC resonant frequency is varied correspondingly thereto. Then, after the varied LC resonant frequency has been measured, the water level corresponding to the amount of the laundry is determined and the water supply valve is closed to stop the supply of water for thereby implementing a proper water level.
During the dehydration operation, since the motor is typically set to rotate at a high speed of about 1700 rotations per minute, a great centrifugal force is generated and drastically affects the laundry within the dehydration tub to thereby cause a strong vibration or noise. Meanwhile, the vibration can not be fully absorbed by means of a balancing device such as a snubber bar which is installed at an upper end portion of the washtub.
In addition, the rotation of the dehydration tub is stopped in accordance with a control of the induction motor. However, since the rotating force caused due to inertia is varied in accordance with the amount of the washing water, the rotation of the dehydration tub is temporarily decreased. In the case that the induction motor is stopped, it is gradually increased. Accordingly, it fails to control the rotation of the dehydration tub to prevent the generation of the vibration and noises.
To overcome the above problems, an improved washing machine capable of sensing the water level and vibration within the washtub during the washing operation is disclosed.
The above improved washing machine has a water level sensor and a vibration sensor. For instance, during the washing and rinsing operations, the water level sensor serves to supply and sense the optimal water level within the washtub, and during the dehydration operation, the vibration sensor functions to sense the vibration generated in the washing machine.
FIGS. 1
to
6
illustrate a conventional washing machine in which a water level sensor and a vibration sensor are installed independently.
As shown therein, the washing machine including a water level sensor and a vibration sensor includes a tank
100
installed within a casing
102
and having an opened top portion and a closed bottom portion, a snubber bar
107
lying between dampers
108
which are respectively assembled at the upper portion of the casing
102
and the lower portion of the tank
100
for absorbing the impact of the tank
100
, a washing and dehydration tub (hereinafter, called as a washtub)
101
installed in the interior of the tank
100
and mounted in a coaxial state with the tank
100
to execute the washing and dehydration operations, the washtub forming a plurality of conically shaped holes on the surface thereof, an induction motor
103
installed at a lower portion of the outer surface of the tank
100
for implementing a reverse rotation, a clutch
104
assembled with the induction motor
103
by means of a pulley belt
105
for delivering and decelerating the rotating force of the induction motor
103
, a pulsator
106
rotatably installed on the inner bottom surface of the washtub
101
and interposed between the washtub
101
and the clutch
104
for swirling the water within the washtub
101
, a water supply valve
109
connected with a water supply path installed at the upper portion of the tank
100
for supplying the water into the washtub
101
, a water discharging valve
110
installed on the bottom surface of the tank
100
for discharging the polluted water to the outside of the washtub
101
, a vibration sensor
112
installed on the inner surface of one side of the upper portion of the casing
102
for sensing the vibration formed by the contact with the tank
100
due to an eccentric rotation of the washtub
101
in accordance with an eccentrically formed laundry in a certain direction, a water pressure transfer path
113
having one end connected to the lower surface of the tank
100
and the other end vertically extended to the upper portion of the tank
100
for transferring the water pressure generated in accordance with the variation of the water level within the washtub
101
, a water level sensor
111
installed at the other end of the water pressure transfer path
113
for changing and outputting an inherent inductance in accordance with the transferred water pressure, a waveform shaping unit
116
for applying a fixed capacitance to the changed value of the inherent inductance to thereby generate a resonant frequency and for then stabilizing the generated resonant frequency with a voltage waveform to thereby amplify and output the resonant frequency, and a microprocessor
114
for determining the vibration and the water level with the vibration sensed by the vibration sensor
112
and the voltage waveform inputted through the waveform shaping unit
116
and for controlling the operation of the induction motor
103
using a motor driving member
115
and the opening and closing operation of the water supply and discharging valves
109
and
110
and a valve driving member
117
in accordance with the determined vibration and the water level.
FIGS. 2 and 3
illustrate the detailed configuration of the water level sensor
111
as shown in FIG.
1
.
The water level sensor
111
is comprised of a cylindrical housing
10
which has a through hole connected through the water pressure transfer path
113
to the tank
100
at one side thereof and an opening hole at the other side thereof, a bellows
11
which is installed within the housing
10
and is connected to the water pressure transfer path
113
to be extended or expanded in accordance with the pressure of water within the washtub
101
, a shielding member
12
which is sealed at the top portion of the bellows
11
and have a hook shape to shield the water pressure, a cylindrical coil
14
having an inherent inductance value, which is installed at the center portion of the inner wall of the housing
10
to be separated by a predetermined
Kim Hyong-Sup
Kwon Oh-Sung
Lim Hyong-Tack
Seo Sang-Ho
Birch & Stewart Kolasch & Birch, LLP
LG Electronics Inc.
Stinson Frankie L.
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