Sensor for detecting both water level and vibration in...

Textiles: fluid treating apparatus – Machines – Single tub and automatic sequential operation mechanism

Reexamination Certificate

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Details

C068S012210, C068S012050, C068S023300

Reexamination Certificate

active

06336348

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a sensor for a washing machine, and more particularly, to a sensor for detecting both a water level and a vibration in a washing machine, which permits detection both of the water level of washing water in a washing tub and the vibration of the washing tub.
2. Background of the Related Art
In general, the washing machine removes contaminant on laundry by conducting a washing, rinsing, spinning cycles in succession. In detail, the washing cycle is a process for separating the contaminant on the laundry by friction between washing water and the laundry caused by water circulation using water circulation producing means, such as a pulsator, and softening action of detergent. And, upon completion of the washing cycle, the rinsing cycle is conducted, in which contaminated water is discharged to outside of the washing machine, fresh water is supplied to the washing tub, and the pulsator is rotated to rinse the laundry. Upon completion of the rinsing cycle, the spinning cycle is started. That is, a motor is rotated at a high speed, to discharge water remained in the laundry to outside of the washing tub by using a centrifugal force.
In the meantime, a water level in the washing tub, quantity of detergent to be used, and a total washing time period are determined in general with reference to an amount of laundry introduced in the washing tub in the conduction of the washing cycle. Once an appropriate water level is determined with reference to the amount of laundry, the washing water is supplied to the washing tub until the washing water reaches to the set water level before the washing cycle or the rinsing cycle is started. In this instance, the water level in the washing tub is detected by means of a water level sensor.
In the meantime, it is unavoidable that vibration and noise are occurred in the spinning cycle as the washing tub spins at a high speed ranging around 1700 rpm. Therefore, in order to attenuate the vibration, vibration attenuation means, such as snubber bar, is provided between the washing tub and the washing machine case. However, in fact it is impossible to absorb the entire vibration generated in the high speed rotation by means of the vibration attenuation means. Therefore, recently, a vibration detection sensor is used for detecting the vibration of the washing tub generated during the spinning cycle, for controlling processing of the spinning cycle according to a degree of the vibration. A related art water level detecting sensor and a related art vibration detecting sensor will be explained.
First, a related art washing machine and a water level detecting sensor will be explained with reference to
FIG. 1 and 2
. There is an outer tub
5
inside of a washing machine case
1
, a washing and spinning tub(hereafter called as “washing tub”)
3
rotatably mounted in the outer tub
5
, and a pulsator inside of the washing tub
3
rotated by a motor
9
. And, there is a snubber bar
6
for attenuating the vibration between the outer tub
5
and the case
1
. And, there is a feed water valve
7
above the washing machine case
1
, and a drain valve
8
connected to the outer tub
5
. There are a water level detecting sensor
10
and a vibration detecting sensor
20
on an upper portion of the washing machine case
1
.
The water level detecting sensor will be explained in detail with reference to
FIGS. 2A
,
2
B and
3
.
The water level detecting sensor
10
is provided with a hydraulic pressure transmission means, such as bellows
12
and diaphragm
12
a
, in a lower portion of a cylindrical housing
11
, a body of the water level detecting sensor
10
, for expanding and contracting in up and down direction on reception of a hydraulic pressure generated by the water level of the washing tub. That is, there is a hydraulic pressure transmission passage
5
a
formed between the hydraulic pressure transmission means and the outer tub
5
, for converting the water level of the washing tub and transmitting to the hydraulic pressure transmission means. There is a coil part
15
having a coil with an inductance on an inside wall of the housing
11
, and a core holder
13
under the coil part
15
for accommodating a core
14
which moves in an inside space of the coil part
15
in an up and down direction for varying the inductance of the coil
15
a
. And, there is a cap
18
over the coil part
15
, and a spring
16
between the cap
18
and the core
14
. That is, when the bellows
12
expands or contracts, the core
14
and the core holder
13
, interlocked with a movement of the bellows
12
, move within a hollow of the coil part
15
in an up and down direction, with the inductance of the coil
15
a
varied.
The operation principle of the water level detecting sensor will be explained.
The coil
15
a
of the coil part
15
is connected to an LC resonance circuit
10
a
, an output terminal of which is connected to a microprocessor
2
. The microprocessor
2
controls the feed water valve
7
and the drain valve
8
with reference to a water level the water level detecting sensor senses. In the washing cycle, the water level is fixed according to an amount of the laundry, and the feed water valve
7
is opened to supply water to the washing tub
3
. During water is supplied to the washing tub
3
, a hydraulic pressure for the water level is transmitted to the hydraulic pressure transmission means, such as the diaphragm
12
a
, through the hydraulic pressure transmission passage
5
a
, to cause the diaphragm
12
a
to expand or contract in proportion to the transmitted hydraulic pressure. That is, as water is supplied to the washing tub
3
, the diaphragm overcomes an elastic force of the spring
16
to expand upward, along with the core
14
on the core holder
13
through the hollow in the coil part
15
. Then, the movement of the core
14
varies the inductance of the coil
15
a
, and the inductance variation of the coil
15
a
is converted into a predetermined resonance frequency at the LC resonance circuit
10
a
. The microprocessor
2
determines the water level in the washing tub with reference to a variation of the resonance frequency. When the measured water level reaches to a preset water level, the feed water valve
7
is closed, to stop water supply, and the motor is put into operation for conducting the washing cycle.
In the meantime, upon completion of the washing cycle, contaminated water in the washing tub is drained, and completion of the drain is also detected by using the water level detecting sensor
10
. That is, as the drain proceeds, the water level in the washing tub drops, to permit the diaphragm
12
a
to return to an initial position by the elastic force of the spring
16
. Accordingly, the core holder
13
having the core
14
mounted thereon also moves downward to an initial position. If the core
14
returns to the initial position, the inductance of the coil part
15
is also reduced, and the reduced inductance is converted into a resonance frequency at the LC resonance circuit
10
a
, with reference to which a drain completion time is determined.
A related art vibration detecting sensor will be explained, with reference to
FIGS. 1 and 4
. There are one pair of contacts
24
and
25
on the washing machine case
1
, and a switch leg
22
rotatably fitted under the contacts
24
and
25
for open or closing the contacts
24
and
25
, electrically. And, there are one pair of springs
23
under the switch leg
22
.
The operation of the vibration detecting sensor will be explained with reference to
FIGS. 3 and 4
. During washing, particularly, during spinning, if the washing tub hits the switch leg
22
of the vibration detecting sensor
20
due to severe vibration of the washing tub, the switch leg
22
overcomes the elastic force of the spring
23
, and rotates in a counter clockwise direction on the drawing, to short the contacts
24
and
25
. Upon occurrence of an electrical signal at any one of the pair of the contacts
24
and
25
, the microprocesso

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