Textiles: fluid treating apparatus – Machines – Combined
Reexamination Certificate
2000-01-14
2002-06-04
Stinson, Frankie L. (Department: 1746)
Textiles: fluid treating apparatus
Machines
Combined
C068S023100, C068S023200
Reexamination Certificate
active
06397643
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a washing machine for washing laundry such as clothes, and more particularly, to a suspension apparatus of a washing machine which makes a washing tub suspended in a casing of the washing machine so as to minimize vibrations and noises generated when the washing machine is operated.
2. Description of the Related Art
In general, automatic washing machines for washing clothes by using agitated water currents may be classified into various types of washing machines depending on the driving system thereof or the type of a pulsator.
FIG. 1
is a vertical sectional view illustrating the internal structure of a conventional directly coupled motor type washing machine, and
FIG. 2
is a vertical sectional view illustrating the internal structure of a conventional clutch type washing machine employing a pulsator.
First, the directly coupled motor type washing machine as shown in
FIG. 1
is rotationally driven according to the operation of a motor
15
since an inner drum
12
is directly connected to the driving shaft
14
of the motor
15
, a washing tub comprised of the inner drum
12
and an outer drum
13
is suspended by four suspension rods
16
in a casing
11
of the washing machine, and the motor
15
is positioned below the outer drum
13
.
The driving shaft
14
of the motor
15
is connected to the inner drum
12
through the outer drum
13
, and while the inner drum
12
rotates according to the operation of the motor
15
, washing operation is performed.
On the other hand, in the clutch type washing machine, a pulsator
29
attached to the bottom surface of an inner drum
22
is rotated by a driving shaft
24
connected to a motor
25
, and a clutch
28
is provided at the driving shaft
24
so that rotational power transmission can be connected or disconnected.
That is, the motor
25
is provided below an outer drum
23
of a washing tub, the motor
25
is connected to the driving shaft
24
via a pulley and a belt
27
, and the clutch
28
is installed in the middle of the driving shaft
24
so that the rotational power transmission can be connected or disconnected.
In addition, while in the directly coupled motor type washing machine the motor directly drives the inner drum, the driving shaft
24
is connected to the pulsator
29
provided in the inner drum
22
as a rotating body, and washing operation is performed as the pulsator
29
is driven to rotate in a state in which the inner drum
22
does not rotate.
The outer drum
23
is connected to a casing
21
of the washing machine by four suspension rods
26
in a suspended manner as in the directly coupled motor type washing machine.
As described above, in both the directly coupled motor type washing machine and the clutch type washing machine, the inner and outer drums in which wash operation is performed are connected in the casing of the washing by the suspension rods as shown in FIG.
3
. Referring to
FIGS. 1 and 3
, a suspension member
16
a
is installed at the upper end of the suspension rod
16
or
26
and fitted to a bracket
11
a
of the casing of the washing machine, and a damping force changing means
17
is installed at the lower end of the suspension rod
16
or
26
and performs damping function during the operation of the washing machine while supporting a bracket
13
a
of the outer drum.
In particular, the damping force changing means
17
is provided with a damper base
17
a
of a flange shape at the lower end of the suspension rod
16
as shown in
FIG. 3
, a damper spring
17
b
is disposed on the upper side of the damper base
17
a
, and a damper cap
17
c
which supports the outer drum
13
is capped over the damper spring
17
b.
Therefore, the load generated from the inner and outer drums is transferred to the damper spring
17
b
via the damper cap
17
c
, and at this time the damper spring
17
b
does buffering function while being supported by the suspension rod
16
.
Since, the distribution of laundry is not symmetrical with respect to the rotating shaft at the early stage of an extraction phase, eccentric load occurs in the washing tub, and accordingly vibrations and noises may be severely generated.
To form a damping force for buffering such vibrations is an important role of the damping force changing means
17
. That is, the damping force converts kinetic energy into thermal energy, etc. to decrease the amplitude of the vibrations, and is, in the damping force changing means
17
, generated by a friction force ++++between the damper base
17
a
and the damper cap
17
c
and the flow of air into or out of the damping force changing means
17
.
However, there is a problem in which when the conventional suspension apparatus employing the suspension rods
16
as described above is designed to have a greater damping force so as to suppress abnormal vibrations due to eccentric load generated at the early stage of an extraction phase, the amplitudes of noises become larger during the normal operation of the washing machine, and when the suspension apparatus is designed to have a lesser damping force so as to decrease the amplitudes of noises generated during the normal operation, excessive vibrations are generated at the early stage of the extraction phase and accordingly walking phenomena of the washing machine may occur.
Consequently, unless a damping force which satisfies the characteristics required during the early stage of the extraction phase and during the normal washing operation is formed, most portions of the vibrational forces generated at the inner and outer drums
12
and
13
are transferred to the casing
11
of the washing machine via the suspension rods
16
, the amplitude of the vibrations of the casing
11
is more increased by the components of the transferred vibrational forces which are near to the resonant frequency of the casing
11
. Therefore, the suspension rods
16
and the outer drum
13
are also vibrated, and accordingly more noises are generated when the washing machine is operated.
SUMMARY OF THE INVENTION
To solve the above problems, it is an objective of the present invention to provide a suspension apparatus of a washing machine which is capable of minimizing vibrations and noises by changing the structure of a damping force changing means so that the damping force of the damping force changing means can vary with acting load generated when the washing machine is operated.
To achieve the above objective, there is provided a suspension apparatus of a washing machine comprising:
suspension rods the upper portions of which are connected to a casing of the washing machine and the lower portions of which are connected to a washing tub so that the washing tub can be supported in the casing in a suspended state;
damper bases installed at the respective lower ends of the suspension rods;
damping force changing means fitted around the respective suspension rods and positioned above the respective damper bases, so as to be compressed according to the variations in load of the washing tub and change the damping force generated when contacting the respective suspension rods; and
elastic means installed between the damping force changing means and the damper bases, respectively, so as to do buffering action, and, in addition, providing compression forces for the damping force changing means, respectively.
REFERENCES:
patent: 3703091 (1972-11-01), Steele
patent: 4729458 (1988-03-01), Bauer et al.
patent: 4867317 (1989-09-01), Wildeman et al.
patent: 5117659 (1992-06-01), Sharp et al.
patent: 5606879 (1997-03-01), Frolicher et al.
patent: 5946946 (1999-09-01), Sharp et al.
patent: 6247687 (2001-06-01), Jensen et al.
patent: 1287037 (1969-01-01), None
patent: 52-54274 (1977-05-01), None
patent: 2-198592 (1990-08-01), None
Chang Jae Won
Hwang Jin Sang
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