WASHING MACHINE
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a washing machine for washing
clothes, for example.
2. Background Art
As a conventional washing machine, a description is provided for a
washing machine disclosed in Japanese Utility Model Unexamined
Publication No. 60-044790 (Patent Literature 1), for example. The washing
machine of Patent Literature 1 has an agitator on the bottom part of a water
tub. The agitator is rotated by a motor so that the water stored in the water
tub is agitated. The washing machine that washes laundry, such as clothes,
with water streams generated by the rotation of the agitator in this manner
is a washing machine having the simplest structure. The washing machine
of Patent Literature 1 is a one-tub washing machine capable of washing and
rinsing laundry in one tub.
As a washing machine having a spin-drying function for spin-drying
the laundry having been rinsed, a description is provided for a washing
machine disclosed in Japanese Utility Model Unexamined Publication No.
59-101986 (Patent Literature 2), for example. The washing machine of
Patent Literature 2 has a spinning tub formed separately from a washing tub.
That is, the washing machine of Patent Literature 2 is capable of spin-drying
the laundry having been washed and rinsed in the washing tub after the
laundry is transferred to the spinning tub. The washing tub has an agitator
for generating water streams, on the bottom part thereof. The agitator is
driven and rotated by a motor. The spinning tub has a spinning basket for

housing the laundry. The spinning basket is driven and rotated by a motor.
The washing machine of Patent Literature 2 is a two-tub washing machine
having the washing tub and the spinning tub inside the housing.
Further, as a washing machine that has a tub serving as both washing
tub and spinning tub (washing/spinning tub) inside the water tub, a
description is provided for a washing machine disclosed in Japanese Utility
Model Unexamined Publication No. 60-002486 (Patent Literature 3), for
example. The washing machine of Patent Literature 3 is capable of
sequentially washing, rinsing, and spin-drying the laundry in one
washing/spinning tub. The washing/spinning tub has an agitator on the
bottom part thereof. In washing and rinsing, the washing/spinning tub is
fixed and the. agitator is rotated so as to generate water streams. In
spin-drying, the washing/spinning tub rotates integrally with the agitator.
The washing machine of Patent Literature 3 is a fully automatic washing
machine.
Laundry operation includes the following steps' washing for removing
the dirt with detergent,' rinsing for removing the detergent used in washing
from the laundry,' and drying for drying the laundry having been washed
(and rinsed). In order to shorten the time taken for drying the laundry, it is
important to reduce the moisture contained in the laundry having been
washed. The spin-drying function of the washing machine reduces the
moisture contained in the laundry having been washed.
However, the two-tub washing machine of Patent Literature 2 requires
the operation of transferring the laundry from the washing tub to the
spinning tub when the laundry having been washed and rinsed in the
washing tub is spin-dried. That is, the washing machine is inconvenient to
use. Further, the washing tub and the spinning tub are formed separately,

and thus the washing machine is large in overall size and requires a large
installation space. Further, the washing machine requires two motors, i.e. a
motor for rotating the agitator of the washing tub, and a motor for rotating
the spinning tub. This makes the washing machine have a complicated
structure, and expensive.
The fully automatic washing machine of Patent Literature 3, washes,
rinses, and spin-dries the laundry in one washing/spinning tub. Thus, a
large washing/spinning tub appropriate to the laundry capacity is necessary.
Further, this washing machine requires a clutch mechanism that switches
the rotation drive of the motor between the washing/spinning tub and the
agitator for transmission in washing/rinsing and spin-drying. Thus, the
fully automatic washing machine of Patent Literature 3 has a more
complicated structure and is more expensive than the two-tub washing
machine of Patent Literature 2.
SUMMARY OF THE INVENTION
The present invention is directed to provide a washing machine that
has a simple structure, ease of use, and a spin-drying function, at a low price.
The washing machine of the present invention includes the following
elements;
a water/washing tub for storing washing water and for washing
laundry;
an agitator/spinning tub rotatably disposed inside the
water/washing tub on the bottom part thereof, the agitator/spinning tub
having a bottomed cylindrical shape open in the top portion thereof; and
a motor for rotating the agitator/spinning tub.
In the washing machine of the present invention, the agitator/spinning tub

has a cylindrical wall. A plurality of holes is formed through the cylindrical
wall. A space portion open upwardly is formed between the outer surface of
the cylindrical wall and the inner surface of the water/washing tub.
This structure eliminates the need for the operation of transferring the
laundry when the laundry is spin-dried sequentially after being washed and
rinsed. With this structure, an inexpensive washing machine that has a
simple structure, ease of use, and a spin-drying function can be provided.
BRIEF DESCRIPTION OF DRAWINGS
Fig. 1 is a sectional view of a washing machine in accordance with a
first exemplary embodiment of the present invention.
Fig. 2 is a plan view of an essential part of the washing machine in
accordance with the exemplary embodiment.
Fig. 3 is a sectional view showing an operating state of the washing
machine in accordance with the exemplary embodiment.
Fig. 4 is a plan view of an essential part showing the operating state of
the washing machine in accordance with the exemplary embodiment.
Fig. 5 is a timing chart showing an operation of the washing machine
in accordance with the exemplary embodiment.
Fig. 6 is a timing chart showing an operation of a washing machine in
accordance with a second exemplary embodiment of the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
FIRST EXEMPLARY EMBODIMENT
Fig. 1 is a sectional view of a washing machine in accordance with the
first exemplary embodiment of the present invention. Fig. 2 is a plan view
of an essential part of the washing machine in accordance with the exemplary

embodiment. Fig. 3 is a sectional view showing an operating state of the
washing machine in accordance with the exemplary embodiment. Fig. 4 is a
plan view of an essential part showing the operating state of the washing
machine in accordance with the exemplary embodiment. Fig. 5 is a timing
chart showing an operation of the washing machine in accordance with the
exemplary embodiment.
With reference to Fig. 1 through Fig. 4, housing 1 of the washing
machine is installed with support legs 2 that are disposed at four corners of
the bottom surface of the housing. Housing 1 is formed of a
corrosion-treated steel sheet, for example, in the shape of a substantially
longitudinal rectangular parallelepiped (including a rectangular
parallelepiped). Inside housing 1, water/washing tub 3 formed of a stainless
steel sheet or by resin molding in a bottomed cylindrical shape or a bottomed
square shape is disposed. In water/washing tub 3, a predetermined amount
of washing water is stored and laundry, such as clothes, is placed.
Above water/washing tub 3, laundry inlet port 4 is disposed. Inlet
port 4 is opened or closed with lid 5 that is detachably attached to housing 1.
Inlet port 4 may be opened or closed with lid 5 that is rotatably attached to
housing 1 at one end. The periphery of inlet port 4 is held by top plate 6.
Top plate 6 fixes the top end of water/washing tub 3 to housing 1, and covers
the gap between housing 1 and water/washing tub 3 from the upward
direction.
Motor 7 is attached to the bottom part of water/washing tub 3 on the
outside thereof. Motor 7 is coupled to decelerator 8 via belt 9. Decelerator
8 decelerates the rotation of motor 7. Decelerator 8 is attached to the bottom
part of water/washing tub 3 on the outside thereof in a substantially central
position (including the center). Motor 7 is attached to the bottom part of

water/washing tub 3 on the outside thereof in a position biased to the outer
peripheral side from the substantially central position (including the center).
Inside water/washing tub 3 on the bottom part thereof,
agitator/spinning tub 10 is disposed rotatably. Agitator/spinning tub 10 is
coupled to decelerator 8 by rotary shaft 11 disposed in the vertical direction.
With this structure, the rotation of motor 7 is transmitted to
agitator/spinning tub 10 via decelerator 8. Agitator/spinning tub 10 is
rotated by driving motor 7, in normal and reverse directions.
Agitator/spinning tub 10 is in a bottomed cylindrical shape that is open
in the top portion and has a tilted inner surface spreading out upwardly.
Agitator/spinning tub 10 is formed by resin molding or formed of a
corrosion-resistant metal sheet, such as a stainless sheet. A plurality of
water flow holes 13 is formed through cylindrical wall 12, i.e. the outer
circumferential side surface of agitator/spinning tub 10. A large number of
water flow holes 13 are formed substantially across the entire circumference
of cylindrical wall 12. Agitator/spinning tub 10 is disposed in the
substantially central position (including the center) of water/washing tub 3.
Space portion 14 open upwardly is formed between the outer surface of
cylindrical wall 12 of agitator/spinning tub 10 and the inner surface of
water/washing tub 3. In space portion 14, the washing water and the
laundry agitated by the rotation of agitator/spinning tub 10 can flow.
Agitator/spinning tub 10 has first agitating part 15 that protrudes
upwardly from the inner bottom surface of the agitator/spinning tub. First
agitating part 15 has a plurality of protrusions 15a. Protrusions 15a are
formed radially from the center toward the outer circumferential direction.
Each protrusion is also formed in an arc shape in the upward direction.
First agitating part 15 agitates the washing water and the laundry, thereby

enhancing the effects of washing and rinsing.
Further, agitator/spinning tub 10 has second agitating part 16 formed
in the directions perpendicular to the inner surface of cylindrical wall 12.
Second agitating part 16 is shaped to have a plurality of projections 16a.
Each projection 16a projects inwardly toward the center of rotation of
agitator/spinning tub 10 and has a top portion formed into a smooth arc
shape toward the top end of cylindrical wall 12. Second agitating part 16
agitates the washing water and the laundry, thereby enhancing the effects of
washing and rinsing. As shown in Fig. 2, protrusions 15a of first agitating
part 15 are circumferentially displaced from respective projections 16a of
second agitating part 16 at an angle of approximately 45° (including 45°).
Further, agitator/spinning tub 10 has third agitating part 17 formed in
the directions perpendicular to the outer surface of cylindrical wall 12.
Third agitating part 17 has a plurality of projections 17a. Projections 17a
outwardly project toward space portion 14 formed between agitator/spinning
tub 10 and water/washing tub 3. By the rotation of agitator/spinning tub 10,
the washing water is properly agitated in space portion 14. That is, third
agitating part 17 agitates the washing water and the laundry, thereby
enhancing the effects of washing and rinsing.
First agitating part 15, second agitating part 16, and third agitating
part 17 are integrally formed so as to reinforce agitator/spinning tub 10.
With the integral formation, agitator/spinning tub 10 has a sturdy structure
resistant to the agitation of the washing water and laundry caused by
rotation, and the centrifugal force exerted on the moistened laundry. Second
agitating part 16 is circumferentially displaced from third agitating part 17
at an angle of approximately 45° (including 45°).
As shown in Fig. 3, the inner surface of cylindrical wall 12 of

agitator/spinning tub 10 is tilted so as to spread out upwardly. That is,
when the inner diameter of the bottom part of agitator/spinning tub 10 is ΦA
and the inner diameter of the opening at the top end of agitator/spinning tub
10 is ΦB, ΦB>ΦA. More specifically, the tilt angle of the inner surface of
cylindrical wall 12 of agitator/spinning tub 10 is 5 to 10°. The height of
cylindrical wall 12 is a 1/2 to 1/3 of height L of water/washing tub 3 from the
bottom. That is, the height of water/washing tub 3 is larger than the height
of cylindrical wall 12 of agitator/spinning tub 10. Thus, the washing water
can be stored to water surface W, which is above the top end of cylindrical
wall 12.
In washing and rinsing, agitator/spinning tub 10 rotates with the
washing water stored to water surface W, which is equal to or higher than a
1/2 of height L from the bottom. Thus, the laundry can be sufficiently
agitated in the washing water. On the other hand, as long as the height of
cylindrical wall 12 of agitator/spinning tub 10 is equal to or higher than a 1/3
of height L from the bottom, the laundry to be spin-dried is housed inside
agitator/spinning tub 10, in spin-drying.
Overflow water port 19 is formed on the side wall surface of
water/washing tub 3. When the water supplied from water supply port 20
exceeds a predetermined amount, overflow water port 19 allows the water to
flow out therefrom so as to prevent the water from overflowing from the top
end of water/washing tub 3. That is, when the supplied water reaches
overflow water port 19, the water flows out from overflow water port 19 and
is discharged outside the washing machine via overflow water pipe 21 and
drain pipe 22. The top end of cylindrical wall 12 is positioned below overflow
water port 19. Overflow water port 19 is disposed higher than water surface
W, which is raised in washing and rinsing, and thus the washing water

including detergent dissolved therein does not flow out from overflow water
port 19. In short, with a predetermined amount of water and a
concentration of detergent appropriate for the amount of laundry, the effect of
washing is exerted. Further, in rinsing, no water flows out uselessly.
Operating part 23 disposed on the upper part of housing 1 has washing
timer 24, spin-drying timer 25, and changeover switch 26. Washing timer 24
also serving as a power supply switch is manually operated, and used to set a
washing time. Motor 7 is rotated at a predetermined number of rotations in
normal and reverse directions. The rotation of motor 7 is decelerated by
decelerator 8, thus rotating agitator/spinning tub 10 alternately in normal
and reverse directions. Thereby, washing operation is performed. In the
rotation in normal and reverse directions, agitator/spinning tub 10 is rotated
in a clockwise direction and a counterclockwise direction. The number of
rotations is 200 to 300 rpm, for example.
Spin-drying timer 25 also serving as a power supply switch is
manually operated, and used to set a spin-drying time, in a manner similar to
that of washing timer 24. Motor 7 is rotated at a predetermined number of
rotations in one direction. The rotation of motor 7 is decelerated by
decelerator 8, thus rotating agitator/spinning tub 10 in the clockwise
direction, for example. Thereby, spin-drying operation is performed. The
number of rotations in spin-drying is set substantially equal to that in
washing.
Water drain cock 27 for draining water (washing water) inside
water/washing tub 3 is opened and closed by manually operating changeover
switch 26. In washing and rinsing, water drain cock 27 is closed so that
water is stored in water/washing tub 3. After washing and rinsing, .water
drain cock 27 is opened so that the water stored in water/washing tub 3 is

drained. The bottom end of overflow water pipe 21 is coupled to drain pipe
22 on the downstream side of water drain cock 27. Therefore, even when
water drain cock 27 is closed, the water from overflow water pipe 21 is
discharged from drain pipe 22 to the outside of the washing machine.
Next, a description is provided for the operation of the washing
machine of this exemplary embodiment, with reference to Fig. 5. First, for
washing, the user opens lid 5, and places laundry, such as clothes, and a
proper amount of detergent in water/washing tub 3 from inlet port 4. Next,
the user operates changeover switch 26 so as to close water drain cock 27.
Thereafter, the user pours an amount of water appropriate for the laundry
into water/washing tub 3 from water supply port 20.
Water/washing tub 3 is capable of storing the supplied water, i.e.
washing water, to a level above the top end of cylindrical wall 12. The user
pours water until water surface W of the washing water becomes higher than
the top end of cylindrical wall 12 such that agitator/spinning tub 10 is
submerged in water. In this state, the laundry is properly agitated inside
water/washing tub 3, and the effects of washing and rinsing are enhanced.
After a predetermined amount of washing water has been poured in
water/washing tub 3 as described above, the user operates washing timer 24
so as to set a washing time. Since washing timer 24 also serves as the power
supply switch, this operation turns on the power supply switch. The
rotation of motor 7 energized by the power-on of the power supply switch is
decelerated by decelerator 8 in a preset reduction ratio, thus rotating
agitator/spinning tub 10 in normal and reverse directions at a speed of 200 to
300 rpm, for example. In short, as shown in Fig. 5, agitator/spinning tub 10
repeats clockwise rotation and counterclockwise rotation alternately.
Thereby, washing is performed.

For example, as shown by arrow R in Fig. 4, agitator/spinning tub 10 is
rotated in the counterclockwise direction as viewed from the top of the
washing machine. In this case, water streams are generated toward the
center of agitator/spinning tub 10 as shown by arrow F in Fig. 4. At this
time, the water surface of the washing water is lowered to height Wl in the
center and raised to height W2 in the periphery, as shown by the alternate
long and short dash lines in Fig. 3, from the initial height of water surface W.
The water surface of the washing water forms a conical shape. In other
words, the water surface of the washing water is lowered to height Wl in
agitator/spinning tub 10, and raised to height W2 outside agitator/spinning
tub 10. In this state, the conical water surface is higher than cylindrical
wall 12, and thus the washing water flows to the inside of agitator/spinning
tub 10, as shown by the arrows in Fig. 3.
When the rotation direction is reversed such that agitator/spinning tub
10 is rotated in the clockwise direction, water streams curved in the reverse
direction of arrow F in Fig. 4 are generated toward the center of
agitator/spinning tub 10. Also in this case, the water surface forms a conical
shape. Overflow water port 19 is disposed above height W2 of the peripheral
portion of the conical water surface, and thus the washing water does not
flow out from overflow water port 19.
The washing water and the laundry inside water/washing tub 3 are
agitated inside and outside agitator/spinning tub 10 by the above water
streams flowing toward the inside of agitator/spinning tub 10. Thereby, the
laundry is effectively washed. The laundry is washed in contact with first
agitating part 15, second agitating part 16, and third agitating part 17
disposed on agitator/spinning tub 10.
Next, rinsing is described. After the time set for washing has elapsed,

the rotation of agitator/spinning tub 10 is stopped. The user operates
changeover switch 26 so as to open water drain cock 27 and drain the
washing water. Thereafter, the user closes water drain cock 27 again and
pours a proper amount of water into water/washing tub 3 from water supply
port 20. Next, when a rinsing time is set by the operation of washing timer
24 in a manner similar to that in washing, the operation similar to that in
washing is performed. That is, the rotation of motor 7 is decelerated by
decelerator 8, thus rotating agitator/spinning tub 10 in normal and reverse
directions at a speed of 200 to 300 rpm, for example. As shown in Fig. 5,
agitator/spinning tub 10 repeats clockwise rotation and counterclockwise
rotation alternately. Thereby, rinsing is performed.
Next, a description is provided for spin-drying, which is performed
sequentially after washing and rinsing. After rinsing is completed, the user
operates changeover switch 26 so as to open water drain cock 27 and drain
water inside water/washing tub 3. The user sets a spin-drying time by
operating spin-drying timer 25 also serving as a power supply switch with
water drain cock 27 opened. Motor 7 energized by the power-on of the power
supply switch is rotated at a predetermined number of rotations in one
direction. The rotation of motor 7 is decelerated by decelerator 8, thus
rotating agitator/spinning tub 10 in the clockwise direction, for example.
Thereby, spin-drying operation is performed. The number of rotations in
spin-drying is set substantially equal to the number of rotations in washing
and rinsing, which is 200 to 300 rpm, for example. In short, the numbers of
rotations in washing, rinsing, and spin-drying are equal to each other, and
this eliminates the need for motor 7 having a plurality of numbers of
rotations. This structure also eliminates the need for a plurality of motors 7
having different numbers of rotations. Thus, the structure of the washing

machine is simplified.
Here, also in rinsing, water streams as shown by the arrows in Fig. 3
are generated such that the water flows to the inside of agitator/spinning tub
10 in a manner similar to that in washing. With these water streams, the
laundry also flows to the inside of agitator/spinning tub 10. When the
laundry placed in water/washing tub 3 is in an amount such that the laundry
can flow into agitator/spinning tub 10 with the water streams, the laundry is
drawn into agitator/spinning tub 10 and agitated. In short, when the
rinsing is completed, the laundry is in agitator/spinning tub 10. Therefore,
before spin-drying sequentially after rinsing, the user does not need to place
the laundry inside agitator/spinning tub 10. That is, the operation of
transferring the laundry is unnecessary. Further, since agitator/spinning
tub 10 is shorter than water/washing tub 3, agitator/spinning tub 10 can be
made small. Thus, an inexpensive washing machine having a simple
structure, ease of use, and a spin-drying function can be provided.
In spin-drying, the laundry is stuck to the inner surface of cylindrical
wall 12 of agitator/spinning tub 10 by a centrifugal force. The water
contained in the laundry flows to space portion 14 through water flow holes
13 formed through cylindrical wall 12. The water flowing into space portion
14 is discharged to the outside of the washing machine through opened water
drain cock 27 from drain pipe 22. The water separated from the laundry
stuck to the inner surface of cylindrical wall 12 by the centrifugal force rises
along the inner surface of cylindrical wall 12, i.e. a tilted surface spreading
out upwardly, goes over cylindrical wall 12, and is discharged to space portion
14 on the outside of agitator/spinning tub 10. The water thus discharged is
discharged to the outside of the washing machine through water drain cock
27 from drain pipe 22, in a manner similar to that of the water flowing out

through holes 13. In short, since cylindrical wall 12 has a tilt spreading out
upwardly, spin-drying effect is enhanced, in addition to dewatering through
holes 13.
SECOND EXEMPLARY EMBODIMENT
Fig. 6 is a timing chart showing an operation of a washing machine in
accordance with the second exemplary embodiment of the present invention.
The second exemplary embodiment is different from the first exemplary
embodiment in that the number of rotations of agitator/spinning tub 10 in
spin-drying is higher than that in washing and rinsing. The other
structures are the same as those of the first exemplary embodiment.
Since the number of rotations of agitator/spinning tub 10 in
spin-drying is higher than that in washing and rinsing, spin-drying effect is
enhanced and drying thereafter is facilitated. As the structure where the
number of rotations of agitator/spinning tub 10 in washing and rinsing is
different from that in spin-drying, power supply control can be used. For
example, in washing and rinsing, agitator/spinning tub 10 is rotated at a low
speed (e.g. 200 rpm) by half-wave control on the frequency of the AC power
supply. On the other hand, in spin-drying, agitator/spinning tub 10 is
rotated at a high speed (e.g. 400 rpm) by full-wave energization at the
frequency.

We Claim:
1. A washing machine comprising:
a water/washing tub for storing washing water and for washing
laundry,'
an agitator/spinning tub rotatably disposed inside the water/washing
tub on a bottom part thereof, the agitator/spinning tub having a bottomed
cylindrical shape open in a top portion thereof; and
a motor for rotating the agitator/spinning tub,
wherein the agitator/spinning tub has a cylindrical wall,
a plurality of holes is formed through the cylindrical wall, and
a space portion open upwardly is formed between an outer surface of
the cylindrical wall and an inner surface of the water/washing tub.
2. The washing machine of claim 1, wherein the water/washing tub is
capable of storing washing water to a level above a top end of the cylindrical
wall.
3. The washing machine of claim 1, wherein a height of the cylindrical
wall of the agitator/spinning tub is a 1/2 to 1/3 of a height of the
water/washing tub.
4. The washing machine of claim 1, wherein an overflow water port is
formed on a side wall surface of the water/washing tub, and a top end of the
cylindrical wall of the agitator/spinning tub is disposed below the overflow
water port.

5. The washing machine of claim 1, wherein the agitator/spinning tub
has a first agitating part that protrudes upwardly from an inner bottom
surface of the agitator/spinning tub.
6. The washing machine of claim 1, wherein the agitator/spinning tub
has a second agitating part that is formed in directions perpendicular to an
inner surface of the cylindrical wall and projects inwardly of the
agitator/spinning tub.
7. The washing machine of claim 1, wherein the agitator/spinning tub
has a third agitating part that is formed in directions perpendicular to the
outer surface of the cylindrical wall and projects outwardly of the
agitator/spinning tub.
8. The washing machine of claim 1, wherein an inner surface of the
cylindrical wall of the agitator/spinning tub is tilted so as to spread out
upwardly.
9. The washing machine of claim 1, wherein the number of rotations of
the agitator/spinning tub in washing and rinsing is equal to the number of
rotations of the agitator/spinning tub in spin-drying.

10. The washing machine of claim 1, wherein the number of rotations
of the agitator/spinning tub in spin-drying is higher than the number of
rotations of the agitator/spinning tub in washing and rinsing.
11. The washing machine of claim 1, wherein

in washing and rinsing, the agitator/spinning tub is rotated with a
predetermined amount of washing water stored inside the water/washing tub,
and
in spin-drying, the washing water inside the water/washing tub is
drained, and the agitator/spinning tub is rotated.

A washing machine includes the following elements: a water/washing
tub for storing washing water and for washing laundry; an agitator/spinning
tub rotatably disposed inside the water/washing tub on the bottom part
thereof; and a motor for rotating the agitator/spinning tub. The
agitator/spinning tub has a bottomed cylindrical shape open in a top portion
thereof. The agitator/spinning tub has a cylindrical wall. A plurality of
holes is formed through the cylindrical wall. A space portion open upwardly
is formed between the outer surface of the cylindrical wall and the inner
surface of the water/washing tub. This structure eliminates the need for the
operation of transferring the laundry when the laundry is spin dried
sequentially after being washed and rinsed.