BACKGROUND OF THE INVENTION
1. Field of the Invention
[0001] The present invention relates to a drum-type washer for washing laundry in a rotating
drum.
2. Background Art
[0002] Conventional drum-type washers have a structure shown in Fig. 8, which will be described
as follows.
[0003] As shown in Fig. 8, a drum-type washer includes drum 1 rotatably mounted in washing
tub 3. Drum 1 has a large number of water-through-holes 2 in the entire outer peripheral
surface. The washer also includes rotating shaft 4 fixed at one end to the rotation
center of drum 1 and at the other end to drum pulley 5. The washer also includes motor
6, which is connected to drum pulley 5 via belt 7 so as to rotate drum 1. Drum 1 has
an opening with lid 8. Washing tub 3 is suspended inside washer body 9 by spring 10
and vibro-isolatedly supported by vibration free damper 11. Vibration of washing tub
3 during spin cycle is prevented from being transmitted to washer body 9 by vibration
free damper 11 and is reduced by amount 12. Washing tub 3 has drain outlet 17a at
its bottom. The washer also includes feed valve 13 for feeding water into washing
tub 3, drainage pump 14 for draining water from washing tub 3, and heater 15 for heating
water in washing tub 3. The washer also includes control device 16, which controls
the operations of motor 6, feed valve 13, drainage pump 14, heater 15, and the like
so as to perform a series of cycles including wash, rinse, and spin cycles. An example
of a conventional technique related to the present invention is shown in Japanese
Patent Unexamined Publication No.
H10-201988.
[0004] The following is a description of the operation of the above-described drum-type
washer.
[0005] First, the user opens lid 8, loads laundry into drum 1, and turns the washer on to
start a wash cycle. As a result, feed valve 13 is opened to feed water into washing
tub 3. When the water reaches a predetermined level, feed valve 13 is closed to stop
feeding water. Then, drum 1 is rotated by motor 6 at low speed, raising the laundry
in drum 1 and then dropping it into the water during the wash cycle. When the wash
cycle is performed for a predetermined time, the water in washing tub 3 is drawn into
drainage pump 14 via drain outlet 17a. Then, drainage pump 14 is operated to drain
the water as intermediate spinning so as to start a rinse cycle. The rinse cycle includes
the same operation as the wash cycle. In a subsequent spin cycle, drum 1 is rotated
at high speed to centrifugally dehydrate the laundry.
[0006] In the wash cycle, the detergent poured into a detergent container (not shown) is
supposed to be poured into washing tub 3 together with the water flowing through feed
valve 13 immediately after washing is started. This operation is done manually or
by other means. When the cleaning water comes into contact with laundry stains, the
detergent cleans and removes stains, providing a high cleaning effect. In the above-described
conventional structure, however, the detergent poured at the start of washing often
drops directly through drain outlet 17a as detergent aggregates before it is completely
dissolved in the water in washing tub 3. This causes the detergent to get into the
drain space and then to be discharged without fulfilling its function.
SUMMARY OF THE INVENTION
[0007] In view of the above-described problem, the present invention provides a drum-type
washer which improves the solubility of detergent so as to allow the detergent to
provide an excellent cleaning effect in the following manner. In a feed-water cycle,
water is first fed into the drain space with the drain valve open; the drain valve
is closed; detergent is poured into the washing tub; the laundry is stirred for a
predetermined time; and the drain valve is opened and closed to produce the convection
of water. The convection of water functions, even if the detergent drops through drain
outlet 17a and accumulates in the drain space, to stir up the accumulated detergent
so as to accelerate to return it into washing tub 3.
[0008] The drum-type washer of the present invention includes a rotating drum rotatable
in a washing tub, the rotating drum having a rotation axis horizontal or inclined
from a horizontal; a drain outlet in a bottom of the washing tub; a motor for rotating
the rotating drum; a feed-water unit for feeding water into the washing tub; a drainage
unit for draining water from the washing tub; a water circulation channel extended
from an opening in a rear side of the washing tub, the water circulation channel being
communicated with a drain space in a downstream of the drain outlet; a drainage channel
communicated with the drain space having a drain valve, the drainage channel being
extended upward via a drainage pump; and a controller for controlling the motor, the
feed-water unit, and the drainage unit so as to perform at least wash, rinse, and
spin cycles. The controller performs the following operations in this order: water
starts to be fed with the drain valve open; the drain valve is closed when a predetermined
water level is reached; detergent is poured into the washing tub; the rotating drum
is rotated for a predetermined time to perform washing; and the drain valve is opened
and closed.
[0009] With this structure, the drain valve is opened and closed to produce the convection
of water. The convection of water functions, even if the detergent drops through the
drain outlet and accumulates in the drain space, to stir up the accumulated detergent
so as to accelerate to return it into the washing tub. This achieves a drum-type washer
which improves the solubility of detergent, thereby allowing the detergent to provide
an excellent cleaning effect.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010]
Fig. 1 is a sectional view of a side of a drum-type washer according to a first embodiment
of the present invention.
Fig. 2 is a rear view of a washing tub of the washer according to the first embodiment.
Fig. 3 is a sectional view of a side of the washing tub, including a drain space,
of the washer according to the first embodiment.
Fig. 4 is a front view of the washer according to the first embodiment.
Fig. 5 is an operation flow of the washer according to the first and second embodiments
of the present invention.
Fig. 6 is an operation flow of a drum-type washer according to a third embodiment
of the present invention.
Fig. 7 is an operation flow of a drum-type washer according to a fourth embodiment
of the present invention.
Fig. 8 is a longitudinal sectional view of a side of a conventional drum-type washer.
DETAILED DESCRIPTION OF THE INVENTION
[0011] First to fourth embodiments of the present invention will be described as follows
with reference to drawings. In the drawings, the dimensions of some components are
exaggerated for clarity. In the second to fourth embodiments, like components are
labeled with like reference numerals with respect to the first embodiment, and the
description thereof will be sometimes omitted. Note that the present invention is
not limited to these embodiments.
FIRST EMBODIMENT
[0012] Fig. 1 a sectional view of a side of a drum-type washer according to a first embodiment
of the present invention. Fig. 2 is a rear view of a washing tub of the washer. Fig.
3 is a sectional view of a side of the washing tub, including a drain space, of the
washer. Fig. 4 is a front view of the washer. Fig. 5 is an operation flow of the washer.
[0013] As shown in Fig. 1, the drum-type washer includes rotating drum 17 rotatably mounted
in washing tub 19. Rotating drum 17 is formed in a bottomed cylindrical shape and
has a large number of water-through-holes 18 in the entire outer periphery. Rotating
drum 17 has rotating shaft 20 as its rotation axis, which is either horizontal or
slightly inclined from the horizontal. More specifically, the rotation axis is inclined
downward from the front side to the rear side of rotating drum 17. Rotating shaft
20 is connected via belt 44 to motor 21, which is fixed on the bottom of washing tub
19 so that rotating drum 17 can be rotated by motor 21 in the forward and reverse
directions. Rotating drum 17 is provided on its inner circumference wall with several
projection boards 22. One of projection boards 22 can be provided with fabric amount
detector 80 for measuring the laundry amount in rotating drum 17.
[0014] The washer also includes body 23 having opening 24, which is formed on the front
side of washing tub 19 and in the direction perpendicular to an upwardly inclined
surface of body 23. Opening 24 is covered with openable lid 25. When washing laundry,
the user opens lid 25 and loads the laundry into rotating drum 17 through opening
24, laundry loading-unloading opening 26 of washing tub 19, and laundry loading-unloading
opening 27 of drum 17. When washing is over, the user unloads the laundry from rotating
drum 17 through these openings. Providing lid 25 in the direction perpendicular to
the upwardly inclined surface of body 23 allows the user to load and unload laundry
without bending over too much.
[0015] Washing tub 19 is swingably suspended from body 23 by spring 28 and damper 29. Washing
tub 19 is provided on its inside bottom with long U-shaped drainage ditch 30 along
the direction of rotating shaft 20. Drainage ditch 30 is equipped with heater 50,
and has drain outlet 31 at a position to its bottom rear side. Drain outlet 31 is
connected to drain space 37, which is connected at its outlet with drainage channel
32 via drain valve 49 as a component of drainage unit 60. Drainage channel 32 is connected
at the other end thereof with drainage pump 33 as another component of drainage unit
60, so that drainage pump 33 drains water from washing tub 19. The washer also includes
feed-water unit 65, which has first feed valve 34a and second feed valve 34b. First
feed valve 34a feeds water directly into washing tub 19 through feed-water channel
36, and second feed valve 34b feeds water into washing tub 19 via detergent container
35 and feed-water channel 36. The washer also includes water level detector 48 for
detecting the water level in washing tub 19.
[0016] The washer also includes control device 39, which has controller 38 composed of a
microcomputer. Controller 38 controls the operations of motor 21, drainage pump 33,
feed valves 34a and 34b, drain valve 49, and other components via a power switching
unit (not shown) so as to control wash, rinse, spin, and dry cycles.
[0017] Control device 39 receives information from an input setting unit (not shown) for
setting an operation course and other conditions, and displays the information on
a display unit (not shown) provided therein. The display unit is on the front side
of body 23, so that the user can see it easily. Control device 39 also has storage
unit 75, which stores data required for controller 38 to control. Storage unit 75
and the display unit can be provided in control device 39 together with controller
38.
[0018] As shown in Fig. 2, washing tub 19 of the washer is provided on its rear side with
rear-side opening 45. Rear-side opening 45 and opening 46 of drain space 37 shown
in Fig. 3 are connected to water circulation channel 47 so that water or air in washing
tub 19 can circulate there.
[0019] In general conventional drum-type washers, drainage channel 32 is extended directly
from the bottom of washing tub 19 and connected to the outside from the bottom of
body 23 of the washer. Therefore, drainage is discharged directly to an outside drainage
channel with gravitational effects.
[0020] Drum-type washers used to be installed in or near bathrooms or other places where
water is used frequently, but now are often installed as part of built-in kitchens,
and therefore, are required to reduce odor of drainage so as not to ruin food in the
kitchens. To reduce the odor, as shown in Fig. 4, drainage channel 32 is designed
in such a manner that water is once raised before being discharged outside through
drainage pump 33. This structure provides a water seal between drainage channel 32
and the outside drain outlet, thereby preventing the water in drainage channel 32
and the water in the outside drainage channel from coming into mutual contact when
the washer is in a normal operation such as a wash cycle.
[0021] The operation of the washer having the above-described structure will be described
as follows based on the flow of Fig. 5.
[0022] In Step 100, the user opens lid 25, loads laundry into rotating drum 17, and closes
lid 25 so that the drum-type washer can be started. In Step 101, the user turns on
the power switch (not shown). In Step 102, the user selects a course and cycles. In
Step 103, the selected program is displayed on the operation panel. In Step 104, the
user presses the start button (not shown) to start the program. In Step 105, lid 25
of the washer is locked.
[0023] Next, in a feed-water cycle, in Step 106, drainage unit 60 is turned on so as to
open drain valve 49. In Step 107, first feed valve 34a is turned on to feed water.
In Step 108, the water is fed into washing tub 19 through first feed-water channel
36. In Step 109, it is determined whether the water in washing tub 19 has reached
a predetermined water level S1 which is, for example, 0 mm or the reset water level.
[0024] When it is affirmatively determined, the process proceeds to Step 110 where first
feed valve 34a is turned off to stop feeding water; otherwise, the process returns
to Step 108 to continue to feed water. In Step 111, drainage unit 60 is turned off
so as to close drain valve 49. In Step 112, second feed valve 34b is turned on to
feed water. In Step 113, the water is made to pass through detergent container 35.
In Step 114, the water is made to pass through feed-water channel 36a. In Step 115,
the water is fed into washing tub 19 together with detergent. As a result, the detergent
is poured into washing tub 19.
[0025] In Step 116, it is determined whether the water has reached a predetermined water
level S2 which is, for example, 60 mm. When it is affirmatively determined, the process
proceeds to Step 117 where second feed valve 34b is turned off to stop feeding water;
otherwise, the process returns to Step 112 to continue to feed water. In Step 118,
motor 21 is driven to start stirring the laundry. In Step 119, it is determined whether
a predetermined stirring time T1 has been reached. When it is affirmatively determined,
the process proceeds to Step 120; otherwise, the process returns to Step 118 to continue
stirring the laundry.
[0026] In Step 120, drainage unit 60 is turned on for a short time, for example, about one
second so as to open drain valve 49, and then is turned off so as to close drain valve
49 quickly. This opening and closing of drain valve 49 causes a stream of water so
as to stir up the detergent accumulated in drain space 37. In Step 121, the stirring
of the laundry is restarted. In Step 122, it is determined whether a predetermined
stirring time T2 has been reached. When it is affirmatively determined, the stirring
of the laundry is stopped in Step 123 and the process proceed to the next cycle; otherwise,
the process returns to Step 121 to restart the stirring of the laundry.
[0027] Assume that in the feed-water cycle, detergent is poured into washing tub 19 after
water is fed and kept in drain space 37 and some of the detergent drops through drain
outlet 31 and accumulates in drain space 37. Even in such a case, the on-off operation
of drainage unit 60 to open and close drain valve 49 can cause the convection of water,
which stirs up the detergent accumulated in drain space 37 so as to accelerate to
return it into washing tub 19. This improves the solubility of detergent, thereby
allowing the detergent to provide an excellent cleaning effect.
[0028] As described above, the drum-type washer of the present invention includes rotating
drum 17, drain outlet 31, motor 21, feed-water unit 65, drainage unit 60, water circulation
channel 47, drainage channel 32, and controller 38. Rotating drum 17 is rotatably
mounted in washing tub 19, and has rotating shaft 20 as its rotation axis, which is
either horizontal or inclined from a horizontal. Drain outlet 31 is in the bottom
of washing tub 19. Motor 21 rotates rotating drum 17. Feed-water unit 65 feeds water
into washing tub 19. Drainage unit 60 drains water from washing tub 19. Water circulation
channel 47 is extended from rear-side opening 45 in the rear side of washing tub 19
in such a manner as to be communicated with drain space 37 in the downstream of drain
outlet 31. Drainage channel 32 is communicated with drain space 37 having drain valve
49, and extended upward via drainage pump 33. Controller 38 controls at least motor
21, feed-water unit 65, and drainage unit 60 so as to perform at least wash, rinse,
and spin cycles.
[0029] Controller 38 performs the following operations in this order: water starts to be
fed with drain valve 49 open; drain valve 49 is closed when a predetermined water
level is reached; detergent is poured into washing tub 19; drum 17 is rotated for
a predetermined time to perform washing; and then drain valve 49 is opened and closed.
[0030] With this structure, in the feed-water cycle, even if detergent poured into tub 19
after water is fed and kept in drain space 37 drops through drain outlet 31 and accumulates
in drain space 37, the convection of water produced by opening and closing drain valve
49 stirs up the accumulated detergent so as to accelerate to return it into tub 19.
This improves the solubility of detergent, thereby allowing the detergent to provide
an excellent cleaning effect.
SECOND EMBODIMENT
[0031] A drum-type washer of a second embodiment of the present invention has the same structure
as that of the first embodiment, and hence, will e described using Figs. 1 to 4.
[0032] The washer of the second embodiment is identical to that of the first embodiment
except that controller 38 controls so that after rotating drum 17 is rotated for a
predetermined time to perform washing, drain valve 49 is opened and closed a plurality
of times.
[0033] The following is a description, with reference to the operation flow of Fig. 5, of
the operation of the washer having the above-described structure of the second embodiment.
The same steps as those in the first embodiment will not be described in the present
embodiment.
[0034] In the feed-water cycle, in Step 120, drainage unit 60 is turned on for a short time,
for example, about one second so as to open drain valve 49, and then is turned off
so as to close drain valve 49 quickly. This opening and closing of drain valve 49
is performed a plurality of times, for example, four times, so that a stronger stream
of water is caused a plurality of times, thereby vigorously stirring up the detergent
accumulated in drain space 37.
[0035] As described above, in the feed-water cycle, even if detergent poured into washing
tub 19 after water is fed and kept in drain space 37 drops through drain outlet 31
and accumulates in drain space 37, the convection of water stirs up the accumulated
detergent so as to accelerate to return it into tub 19. The convection of water is
produced in drain space 37 by opening and closing drain valve 49 a plurality of times.
This improves the solubility of detergent, thereby allowing the detergent to provide
an excellent cleaning effect.
[0036] Thus, according to the drum-type washer of the present invention, the opening and
closing of drain valve 49 is performed a plurality of times.
[0037] With this structure, the detergent accumulated in drain space 37 can be stirred up
and returned to washing tub 19 more easily. This further improves the solubility of
detergent, thereby allowing the detergent to provide an excellent cleaning effect.
THIRD EMBODIMENT
[0038] Fig. 6 is an operation flow of a drum-type washer according to a third embodiment
of the present invention. A sectional view of a side of the washer, and a rear view
of washing tub 19 of the washer are identical to those in the first and second embodiments,
and hence, will be described with reference to Figs. 1 to 4.
[0039] The washer of the present third embodiment is identical to those of the first and
second embodiments except for the following differences. The washer of the present
embodiment includes water heater 50 for heating water in washing tub 19, and controller
38 controls so that drain valve 49 is opened and closed after water heater 50 is stopped.
[0040] The following is a description, with reference to the operation flow of Fig. 6, of
the operation of the washer having the above-described structure of the third embodiment.
The same steps as those in the first and second embodiments will not be described
in the present embodiment. More specifically, the description of Steps 100 to 105
before in the feed-water cycle, and Steps 106 to 118 in the feed-water cycle will
be omitted.
[0041] In feed-water cycle, in Step 118, the laundry starts to be stirred. In Step 201,
water heater 50 is turned on to heat the water in tub 19. In Step 202, it is determined
whether the water has reached a predetermined temperature X1. When it is affirmatively
determined, the process proceeds to Step 203 where water heater 50 is turned off;
otherwise, the process returns to Step 201 where water heater 50 is continued to be
turned on so as to increase the temperature of the water.
[0042] When the predetermined temperature X1 is reached, water heater 50 is turned off in
Step 203. In Step 120, drainage unit 60 is turned on for a short time, for example,
about one second so as to open drain valve 49, and then is turned off so as to close
drain valve 49 quickly.
[0043] Assume that in the feed-water cycle, detergent is poured into washing tub 19 after
water is fed and kept in drain space 37, and some of the detergent drops through drain
outlet 31 and accumulates in drain space 37. Even in such a case, the heated water
is brought into contact with the detergent accumulated in drain space 37. This improves
the solubility of the detergent stirred up by the convection of water produced in
drain space 37, thereby allowing the detergent to provide an excellent cleaning effect.
[0044] As described above, the drum-type washer of the present invention includes water
heater 50 for heating water in washing tub 19, and controller 38 controls so that
the opening and closing of drain valve 49 is performed after water heater 50 is stopped.
[0045] With this structure, the heated water is brought into contact with the detergent
accumulated in drain space 37, and the convection of water produced in drain space
37 stirs up the detergent. This improves the solubility of detergent, thereby allowing
the detergent to provide an excellent cleaning effect.
FOURTH EMBODIMENT
[0046] Fig. 7 is an operation flow of a drum-type washer according to a fourth embodiment
of the present invention. A sectional view of a side of the washer, and a rear view
of washing tub 19 of the washer are identical to those in the second and third embodiments,
and hence, will be described with reference to Figs. 1 to 4.
[0047] The washer of the present fourth embodiment is identical to those of the second and
third embodiments except for the following differences. The washer of the present
embodiment includes fabric amount detector 80 for measuring the laundry amount in
rotating drum 17, for example, near the outer periphery of washing tub 19, and controller
38 controls so that when the laundry amount is large, drain valve 49 is opened and
closed a larger number of times than when the laundry amount is small.
[0048] The following is a description of the operation of the washer having the above-described
structure of the present embodiment. The same steps as those in the second and third
embodiments will not be described in the present embodiment.
[0049] In Step 104, the user presses the start button to start the program. In Step 105,
lid 25 of the washer is locked. In Step 301, the fabric amount detector determines
the laundry amount in rotating drum 17. Next, in the feed-water cycle, water is fed
into washing tub 19 together with detergent in the same manner as in the second and
third embodiment during Steps 106 to 117.
[0050] Step 117 is followed by Step 302 where the laundry starts to be stirred. In Step
303, it is determined whether a predetermined stirring time T1 has been reached. When
it is affirmatively determined, the process proceeds to Step 304; otherwise, the process
returns to Step 302 where the laundry is continued to be stirred. In Step 304, it
is determined whether the laundry amount determined in Step 301 exceeds a predetermined
fabric amount R1, for example, one half the rated capacity. When it is affirmatively
determined, the process proceeds to Step 305 where drainage unit 60 is turned on for
a short time, for example, about one second so as to open drain valve 49, and then
is turned off so as to close drain valve 49 quickly. This opening and closing of drain
valve 49 is performed a plurality of times, for example four times.
[0051] When the laundry amount determined in Step 301 is determined to be less than the
predetermined fabric amount R1, on the other hand, the process proceeds to Step 306
where drainage unit 60 is turned on for a short time, for example, about one second
so as to open drain valve 49, and then is turned off so as to close drain valve 49
quickly. In this manner, when the laundry amount or the fabric amount is low, the
opening and closing of drain valve 49 is performed fewer times than in the case that
the fabric amount is high. The fewer times can be, for example, only once.
[0052] As described above, when the laundry amount is large, the opening and closing of
drain valve 49 is performed a large number of times. As a result, even when the amount
of detergent is large, the detergent accumulated in drain space 37 can be stirred
up and returned into washing tub 19 easily. This improves the solubility of detergent,
thereby allowing the detergent to provide an excellent cleaning effect.
[0053] When the laundry amount is small, the opening and closing of drain valve 49 is performed
a small number of times, thereby preventing part of the small amount of detergent
from dropping into drainage channel 32. As a result, the detergent provides an excellent
cleaning effect.
[0054] As described hereinbefore, the washer of the present invention includes fabric amount
detector 80 for measuring the laundry amount loaded into rotating drum 17, and controller
38 controls so that when the laundry amount is large, drain valve 49 is opened and
closed a larger number of times than when the laundry amount is small.
[0055] With this structure, when the laundry amount is large, even if a large amount of
detergent is accumulated in drain space 37, it can be stirred up and returned into
washing tub 19 easily by repeating opening and closing drain valve 49. This improves
the solubility of detergent, thereby allowing the detergent to provide an excellent
cleaning effect.
[0056] When the laundry amount is small, on the other hand, the opening and closing of drain
valve 49 is performed a small number of times, thereby preventing part of the small
amount of detergent from dropping into drainage channel 32. As a result, the detergent
provides an excellent cleaning effect.
[0057] As described hereinbefore, according to the drum-type washer of the present invention,
in the feed-water cycle, even if detergent drops through the drain outlet and accumulates
in the drain space, the drain valve is opened and closed to produce the convection
of water in the drain space, and the convection of water stirs up the accumulated
detergent so as to accelerate to return it into the washing tub. This achieves a drum-type
washer which improves the solubility of detergent, thereby allowing the detergent
to provide an excellent cleaning effect.