Clothes washer with balancing devices for dynamically counteracting imbalances

A clothes washing machine has a spin basket with upper and lower balancing devices respectively disposed on upper and lower parts of the spin basket. The lower balancing device has a liquid such as a saline solution occupying the interior thereof. The lower balancing device includes an upper body integrally formed on the spin basket, and a lower body joined to the upper body. At least one of the bodies includes radially spaced concentric ribs that form annular chambers. Liquid is disposed in each chamber, and possibly also movable balls are disposed in each chamber.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a clothes washing machine. More 
particularly, it relates to a washing machine which has an improved 
unbalance compensating function by providing balancing devices for 
dynamically counteracting imbalances 
2. Discussion of Related Art 
FIG. 10 depicts a longitudinal sectional view of a washing machine equipped 
with a conventional balancing device. 
The washing machine includes a spin basket 2 and a fixed basket 3 disposed 
inside of a main body 1. The spin basket 2 has a number of drain holes on 
its surface and serves as a hydro-extracting (spin dry) member. The fixed 
basket 3 is mounted outside of the spin basket 2 and serves as a container 
for containing water. The fixed basket 3 is supported by suspension arms 4 
fixed to the top of the main body 1. The washing machine also includes a 
pulsator 5 which is located on the bottom of the spin basket 2, a driving 
unit 6 that is installed under the spin basket 2 so as to rotate the spin 
basket 2 and the pulsator 5. 
In such a washing machine, laundering is performed by the action of 
detergent and water put into the washing machine and water current 
generated by the rotation of the pulsator 5, and dehydrating is performed 
by centrifugal force applied during spinning of the spin basket 2 so as to 
leave the clothes with just enough moisture for ironing. Full automatic 
washing machines have a microcomputer that is programmed to automatically 
execute the overall laundering process such as the water filling, washing, 
rinsing, draining and dehydrating. 
When the spin basket 2 rotates at high speeds so as to extract excess 
moisture from the wet laundry in a condition that the laundry has gathered 
only at one side of the spin basket 2, its center of gravity deviates from 
the center of rotation, which causes the spin basket 2 to be in an 
out-of-balance state. The out-of-balance spin basket 2 results in 
excessive amounts of vibration and noise which increase the possibility of 
damaging; the components of the washing machine. 
A balancing device 7 containing liquid is installed on the upper part of 
the spin basket 2 in order to keep the dynamic balance of the spin basket 
2. The balancing device 7 includes a ring-shaped case formed by joining 
upper and lower parts together by thermal bonding, and a saline solution 
10 that is filled up to 50% in the case to counteract the imbalance. 
According to the conventional washing machine, because the balancing device 
7 is installed just on the upper part of the spin basket 2, it does not 
effectively offset unbalanced forces when a large amount of the laundry 
inside the spin basket 2 is concentrated at one side of the center of 
rotation. 
To explain it more specifically, referring to FIG. 11, when the spin basket 
2 begins to rotate at high speeds in order to extract excessive moisture 
from the laundry L concentrated into one spot within the spin basket 2, 
the saline solution 10 flows to the opposite side of the laundry. When the 
eccentricity of the laundry L in the spin basket 2, however, is too great 
compared with the single balancing device 7 to counteract it, the 
out-of-balance condition of the spin basket 2 cannot be properly corrected 
by the movement of the saline solution 10. In other words, because the 
centrifugal force F1 of the laundry L situated to one side is larger than 
the centrifugal force F2 of the saline solution 10 that serves to balance 
the out-of-balancing spin basket 2, the basket 2 does not tend to revolve 
on the geometric axis 0 but turns around the axis of rotation 0' leaning 
towards where the laundry L is located. 
Accordingly, as the axis of rotation 0' revolves around the geometric axis 
0 in direction R' in FIG. 11, the spin basket 2 is out-of-balance, and 
collides with the integrated components resulting in excessive noise and 
vibration. 
Besides, a moment M1 resulting from the weight of the laundry L is larger 
than an opposite moment M2 resulting from the saline solution 10 in the 
spin basket 2 to generate rotating forces acting to left and right. 
Imbalanced force and moment are then applied to the spin basket 2 which 
makes noise. 
In conclusion, if the spin basket of a washing machine with the 
conventional balancing device begins to rotate to remove excess moisture 
from wet laundry while a large amount of the laundry is situated to one 
side therein, dynamic forces and moments on the washing machine are 
unbalanced which cause the machine to vibrate thereby creating noise and 
damage to its mechanism. Accordingly, the conventional balancing device is 
inadequate for washing machines with a large hydro-extracting capacity. 
SUMMARY OF THE INVENTION 
Accordingly, the present invention is applied to a washing machine obviate 
one or more of the problems due to limitations and disadvantages of the 
related art. 
It is an object of the present invention to provide a washing machine 
having balancing devices formed on the upper and lower parts respectively, 
of the spin basket for the purpose of enhancing the unbalance compensating 
operation and hydro-extracting capacity. 
It is another object of the present invention to provide a washing machine 
having balancing devices in which a balancing liquid is filled in a spin 
basket's large lower part enough to balance the rotating forces and 
moments acting on the spin basket. 
It is still another object of the present invention to provide a washing 
machine having upper and lower balancing devices of which the lower 
balancing structure is improved for easy fabrication and for sure 
prevention against leakage of the balancing liquid contained in the 
balancing devices. 
According to one aspect of the present invention, there is provided a 
washing machine with a housing, a fixed basket installed in the housing, a 
spin basket mounted within the fixed basket, and upper and lower balancing 
devices respectively provided to upper and lower parts of the spin basket. 
The lower balancing device has a balancing member attached to the 
periphery of the lower part of the rotating cylinder by thermal bonding, 
and a liquid filling the interior of the balancing member. The liquid is 
preferably a saline solution. 
According to a further aspect of the present invention, there is provided a 
washing machine with a lower balancing device having an upper body 
integrally formed on a bottom cover attached to the lower part of the spin 
basket, and a lower body joined to the upper body. A plurality of upper 
ribs are mounted concentric to the axis of rotation and extend downward 
from the lower part of the upper body, and a plurality of lower ribs are 
formed concentric to the axis and extend upward from the upper part of the 
lower body. Each of the innermost and outermost ribs has flanges extending 
axially and having screw holes, and the upper and lower bodies are joined 
together by screws through the screw holes. The lower ribs respectively 
have grooves on the tops and seal rings are inserted into the grooves so 
that the upper ribs are joined to the corresponding lower ribs with the 
seals for forming a seal. 
According to a yet further aspect of the present invention, there is 
provided a washing machine with a lower body having a plurality of ribs 
formed concentric to its axis and extending upward on the upper part of 
the lower body, and an upper body having grooves which the ribs are fitted 
into on the lower part of the upper body. The outermost groove of the 
upper body and the outermost rib of the lower body have a plurality of 
screw holes on their respective sides so that the upper and lower bodies 
are joined together by screws through the screw holes. Of the spaces 
between the ribs, the innermost space is the smallest of all and the 
outermost space is the largest, and different sized tracks are formed by 
adjacent ribs. A liquid is contained in each track to dynamically 
counterbalance an out-of-balance spin basket. In addition, a plurality of 
different sized balls are movably located in the respective tracks, with 
the ball size corresponding to the track size. 
It is to be understood that both the foregoing general description and the 
following detailed description are exemplary and explanatory, which are 
intended to provide further explanation of the invention as claimed.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
Reference will now be made in detail to the preferred embodiments of the 
present invention, examples of which are illustrated in the accompanying 
drawings. 
As shown in FIG. 1, the construction of the washing machine is similar to 
that of FIG. 10, except for the balancing device. Thus, redundant 
descriptions of features common to the conventional system and the 
preferred embodiments of the present invention are omitted. 
The first preferred embodiment of the present invention has a feature that 
balancing devices 7 and 17 for dynamically balancing a spin basket 2 are 
respectively provided at the upper and lower parts of the spin basket 2. 
The upper balancing device 7 is formed to be the same as a conventional 
one. The upper balancing device 7 has a tube 8, a cover 9 bonded to the 
upper section of the tube 8, and a saline solution 10 substantially 
filling 50% of the tube 8. 
The lower balancing device 17 is formed on the periphery of the lower part 
of the spin basket 2. The lower balancing device 17 is sealed up not by 
using a secondary cover but by thermally attaching its tube 18 to the 
lower part of the spin basket 2, and a saline solution 10 fills 
substantially half of the tube 18. The spin basket 2 and tubes 8 and 18 of 
the present invention can be formed by slightly modifying the conventional 
ones. In case that the periphery of the lower part of the spin basket 2 is 
not flat, a flat sheet 24 is provided thereto so that a conventional tube 
can be sealed up without any gap being created. 
In this washing machine, laundering is performed by the actions of 
detergent and water put into the washing machine and water current created 
by the low-speed rotation of the pulsator 5, and excess water can be 
removed from wet laundry by centrifugal force acting on the spin basket 2 
to thereby leave the wash with just enough moisture for ironing. 
The counterbalancing action of the inventive balancing devices at the time 
of hydro-extraction will be described as follows with reference to the 
embodiments of FIGS. 2 and 3. 
Referring first to FIG. 2, when the spin basket 2 containing laundry L 
rotates at high speeds for hydro-extraction, a liquid contained in each of 
the upper and lower balancing devices 7 and 17 moves to the opposite side 
of the laundry L. 
Centrifugal force F1 produced by the laundry L situated to one side in the 
spin basket 2 oppositely acts with respect to centrifugal forces F2 and F3 
generated by the liquid in the upper balancing devices 7 and 17 so as to 
keep a balance of the rotating forces acting on the washing machine. 
Referring now to FIGS. 3A, 3B and 3C, the balancing of moments is described 
as follows. 
As shown in FIGS. 3B and 3C, the reference numerals denote the following: w 
the weight of the laundry gathered; W the weight of the spin basket; O the 
center of gravity of the spin basket 2; .epsilon. the offset distance 
between the center of gravity O of the spin basket 2 and the center of 
rotation C; L the distance between the center of gravity of the laundry 
and the center of rotation C; w.sub.1 the weight of the saline solution 10 
of the upper balancing device 7; L.sub.1 the distance between the center 
of gravity of the saline solution 10 in the upper balancing device 7 and 
the center of rotation C; w.sub.2 the weight of the saline solution 10 of 
the lower balancing device 17; and L.sub.2 the distance between the center 
of gravity of the saline solution 10 in the lower balancing device 17 and 
the center of rotation C. 
The balancing of moments is achieved when the following equation is 
satisfied: 
EQU wL=(.epsilon..cndot.W)+(w.sub.1 .cndot.L.sub.1)+(w.sub.2 .cndot.L.sub.2) 
On the contrary, a conventional washing machine includes a balancing device 
formed just on an upper part of a spin basket and achieves a less 
effective counterbalancing action. Such a conventional washing machine can 
be in a perfect balance condition provided the following equation is 
satisfied: 
EQU wL=(.epsilon..cndot.W)+(w.sub.1 .cndot.L.sub.1) 
The inventive washing machine has a counterbalancing capacity increased by 
w.sub.2 and L.sub.2 as compared to the conventional machine. In other 
words, the eccentricity can be compensated by the moment (w.sub.2 
.cndot.L.sub.2) in the washing machine of the present invention whereby 
the overall counterbalancing capacity is increased. 
Accordingly, the axis of rotation is corrected to the geometric axis O by 
the upper and lower balancing devices 7 and 17 so that the spin basket 2 
can turn without vibration, despite the gathered laundry L. 
FIGS. 4 to 7 relate to a second preferred embodiment of the present 
invention. 
According to the second preferred embodiment of the present invention, a 
lower balancing device 20 may have an increased capacity for containing a 
liquid and is designed to be of a superior construction than that of the 
first preferred embodiment so as to facilitate its fabrication. 
Likewise, the second preferred embodiment includes upper and lower 
balancing devices 7 and 20 respectively provided to upper and lower parts 
of a spin basket 2, as shown in FIG. 4. The lower balancing device 20 is 
integrally mounted on a bottom cover 25 of the spin basket 2. 
The second embodiment of the present invention is featured by the 
construction of the lower balancing device 20 depicted in detail in FIG. 
5. The lower balancing device 20 includes upper and lower bodies 30 and 40 
that are made of aluminum by die-casting. 
The upper body 30 of the lower balancing device 20 is integrally formed on 
the bottom cover 25 of the spin basket 2. Therefore, the lower balancing 
device 20 can be more simply fabricated. Particularly, a relatively large 
space is ensured by the use of the bottom cover 25 so that the lower 
balancing device 20 may contain a large amount of liquid enough to 
effectively perform the counterbalancing action. Besides, the large amount 
of liquid lowers the center of gravity of the spin basket 2, and enables 
the basket 2 to be little influenced by the imbalances of rotation. 
The upper body 30 has on its lower edge a plurality of upper ribs 31, 31a 
and 31b extending downward and annularly concentric to the axis of 
rotation. The lower body 40 includes on its upper edge a plurality of 
lower ribs 41, 41a and 41b extending upwards and annularly concentric to 
the axis of rotation, the ribs 41, 41a and 41b corresponding to respective 
ribs 31, 31a and 31b. The lower balancing device 20 contains a saline 
solution filling 50% of each of the tracks or chambers formed by the upper 
and lower ribs coupled to each other. 
Each of the inner ribs 31a and 41a and the outer ribs 31b and 41b has a 
laterally extending flange 32 and 42. The flanges 32 and 42 are 
respectively disposed in circumferentially spaced relationship (se FIG. 
6), and have screw holes 33 and 43 so that the upper and lower bodies 30 
and 40 are fastened to each other by the use of screws. The lower ribs 41, 
41a and 41b each have one of groove 44 on its top, and rubber rings 50 fit 
into the grooves 44 so as to prevent the saline solution from leaking 
between the ribs 31 and 41 when the upper ribs 31, 31a and 31b and the 
corresponding lower ribs 41, 41a and 41b are joined together. 
FIG. 6 depicts a plan view of the upper body 30 of the lower balancing 
device 20 of FIG. 4. 
As shown in FIG. 6, a plurality of screw holes 35 are formed in the upper 
surface of the upper body 30 of the lower balancing device 20 (i.e. on the 
upper surface of the bottom cover 25) so that the upper body 30 of the 
lower balancing device 20 can be screwed to the spin basket 2. Reference 
numeral 26 denotes an opening into which a driving shaft of the pulsator 5 
is inserted and reference numeral 27 designates a plurality of drain holes 
formed in the bottom of the spin basket 2. 
The following description concerns the operations of the preferred 
embodiments of the present invention. 
FIG. 7 is a view for showing the balanced state achieved by the upper and 
lower balancing devices 7 and 20 during the rotation of the spin basket 2. 
If the spin basket 2 turns at high speeds in order to extract excess water 
from laundry L while the laundry L in the spin basket 2 is being situated 
to the left side in FIG. 7 and is in an out-of-balance condition, the 
saline solution 10 contained in the upper and lower balancing devices 7 
and 20 is concentrated into the right side, i.e. the opposite side of the 
laundry L by centrifugal force. Thus, the force and moment produced by the 
laundry L may be offset by the action of the saline solution 10 located on 
the opposite side of the laundry L so that the spin basket 2 can be in the 
balanced state. The rest of the second embodiment is similar to the first 
embodiment, and further descriptions are omitted. 
The lower balancing device 20 of the present invention is designed to have 
a large enough capacity to contain a large amount of the saline solution 
10, so even when the amount of the laundry L is large, the balancing of 
force and moment can be stable. On the contrary, in case that the laundry 
L is evenly distributed over the interior of the spin basket 2 and the 
center of gravity is located on the geometric axis O (FIG. 3A), the saline 
solution 10 is evenly distributed within the upper and lower balancing 
devices 7 and 20 so that the spin basket 2 can rotate without vibration. 
The lower balancing device 20 of the present invention is arranged to be 
divided into separate tracks or chambers by the ribs 31 and 41, and the 
counterbalance is separately created in each track so as to balance more 
stably the out-of-balance spin basket. 
FIGS. 8, 9A and 9B refer to a third preferred embodiment of the present 
invention. 
A lower balancing device 20a in accordance with the third preferred 
embodiment, is substantially similar to the second embodiment of this 
invention. The following description relates to features of the lower 
balancing device 20a of the third preferred embodiment compared to the 
lower one 20 of the second preferred embodiment. 
As shown in FIG. 8, the lower balancing device 20a of the third preferred 
embodiment is also integrally formed on a bottom cover 25 of a spin basket 
2. 
Referring now to FIG. 9A, the lower balancing device 20a includes upper and 
lower bodies 60 and 70 that are joined to each other. The upper body 60 
has a plurality of grooves 61 formed concentric with the axis, spaced 
radially from each other on the lower surface. The innermost space between 
the grooves 61c and 61d is the smallest (narrowest) of all, and the 
outermost space between the grooves 61a and 61b is the largest (widest). 
The lower body 70 has on the upper surface a plurality of upwardly 
projecting ribs 71 that are axially formed to correspond to the grooves 
61a, 61b, 61c and 61d. Seals 50 are respectively interposed between the 
grooves 61 and the ribs 71 for forming a seal. A plurality of screw holes 
65 and 75 are respectively formed along the sides of the outermost groove 
61a and the outermost rib 71a. 
The ribs 71a, 71b, 71c and 71d of the lower body 70 are fitted into the 
corresponding grooves 61a, 61b and 61c of the upper body 60 together with 
the seals 50, and screws are tightened to easily and firmly couple the 
upper and lower bodies 60 and 70 together. 
As shown in FIG. 9B, according to the third preferred embodiment of the 
present invention employ, a plurality of balls 74 and liquid are provided 
in the respective tracks 72a, 72b and 72c formed to be different in size 
by the ribs 71a, 71b, 71c and 71d. The balls are designed to be of 
different sizes corresponding to each track in which the balls are 
contained. The smallest ball size 74c is located in the innermost track 
72c, and the biggest ball size 74a is in the outermost track 72a. The 
different sized balls 74 are moved to the opposite side of the unbalanced 
laundry so that the imbalances can be removed and a greater magnitude of 
moment be created. 
It is preferable that the balls 74 are made from a relatively heavy 
metallic material such as steel. The liquid contained in the tracks 72 is 
preferably an oil 10a with high viscosity to reduce the noise made by the 
balls when the spin basket 2 is in operation. 
Therefore, the balls 74 that are situated in their respective tracks 72 
together with the oil 10a are evenly distributed to carry out a more 
enhanced balancing movement. Since the operation of the third preferred 
embodiment is similar to that of the second embodiment, further 
descriptions are omitted. 
As discussed above, the present invention can enhance the effectiveness of 
the counterbalance by the mutual actions of the upper and lower balancing 
devices respectively provided to the upper and lower parts of the spin 
basket so that the vibration of the high-speed spin basket can be more 
effectively removed. 
The lower balancing device is designed to be formed integrally on the 
bottom cover attached to the lower part of the spin basket, and its 
components, upper and lower bodies are joined by the simple use of screws 
thereby facilitating the assembling and ensuring a spacious area necessary 
for the counterbalance. 
Besides, the lower balancing device having a large area is designed to be 
divided into a plurality of tracks in such a manner that the 
counterbalancing movement is separately carried out by the liquid 
contained in each track to maximize the counterbalancing action of the 
lower balancing device. The tracks containing the oil are of different 
sizes and the plurality of the different sized balls are located in the 
corresponding tracks so as to dynamically balance the out-of-balance spin 
basket. 
It will be apparent to those skilled in the art that various modifications 
and variations can be made in a washing machine with balancing devices of 
the present invention without departing from the spirit or scope of the 
invention. Thus, it is intended that the present invention cover the 
modifications and variations of this invention provided they come within 
the scope of the appended claims and their equivalents.