Washing machine

A washing basket doubling as a spin-drier is disposed rotatably in a water-tub. A motor drives the basket, which generates centrifugal force. The centrifugal force cause cleansing water to run through the fibers of clothes in the basket, thereby cleansing the clothes. A control device cause variation of the spinning of the basket so that the centrifugal force working on the clothes is varied, which cleanses the clothes more effectively. The clothes in the basket receive only water-moving-force, and they can be cleansed without being damage or entangled.

FIELD OF THE INVENTION
 The present invention relates to a washing machine for cleansing clothes.
 It relates more particularly to a washing machine that spins a washing
 basket containing clothes, thereby generating centrifugal force which
 produces a water stream, and the water stream runs through the clothes, so
 that soil is removed from the clothes.
 BACKGROUND OF THE INVENTION
 A conventional washing machine, in general, employs an agitating method.
 That is, a user puts the clothes into a washing basket doubling as a
 spin-dryer (hereinafter referred to as a "basket") in the first place,
 then supplies water into the basket up to a given level. After that, the
 user agitates the agitator (pulsator) disposed in the basket to cleanse
 and rinse the clothes.
 The agitating is performed by repeating the steps of clockwise spinning,
 halting, counterclockwise spinning of the pulsator, halting. Respective
 periods of clockwise spinning and counterclockwise spinning are determined
 at a given duration so that the clothes are sufficiently agitated. The
 halt period is also determined at a necessary time for starting the
 reverse spin after the agitating has been halted.
 In this conventional structure, the pulsator agitates the clothes, and the
 pulsator contacts the clothes directly or via water, thereby revolving the
 clothes to be cleansed. This structure produces a powerful cleansing
 effect; however, the clothes directly contact the pulsator, so that the
 clothes become vulnerable to damage.
 Further, the clothes frequently move and revolve up and down, and left and
 right, whereby the clothes get entangled in a complicated manner with each
 other. When the clothes get entangled, the centrifugal force due to
 spinning the basket in the next step, i.e. dehydrating; is impressed to
 the clothes, whereby the entangled clothes are forcibly stretched and
 pressed onto an inside wall of the basket. As a result, the clothes lose
 their shape, and are hard to take out from the basket after the
 dehydrating step.
 SUMMARY OF THE INVENTION
 The present invention addresses the problems discussed above and aims to
 provide a washing machine where only movements of the water only work to
 on articles to be cleansed so that the articles are kept free from damage
 and entanglement.
 The washing machine of the present invention comprises the following
 elements:
 (a) a water tub;
 (b) a washing basket doubling as a spin-drier rotatably disposed in the
 water tub;
 (c) a driving machine for driving the basket; and
 (d) a control device for controlling the driving machine.
 The control device is so structured that it spins the basket, and varies
 centrifugal force applied to the water in the basket in order to cleanse
 the articles.
 The structure discussed above allows the water stream including detergent
 to run through the fibers of the clothes thereby removing soil from the
 articles. As such, because the articles receive only the force due to
 water movement by the centrifugal force, the articles can be cleansed
 without damage and entangled.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS
 Exemplary embodiments of the present invention are described hereinafter
 with reference to the accompanying drawings.
 Exemplary Embodiment 1
 FIG. 1 is a cross section of a washing machine in accordance with the first
 exemplary embodiment of the present invention, and FIG. 2 is a block
 circuit diagram of the washing machine shown in FIG. 1.
 In FIG. 1, a water tub 1 has a washing basket doubling as a spin-drier 2
 therein. (Hereinafter the washing basket doubling as a spin-drier 2 is
 referred to as a "basket 2".) Water tub 1 is suspended by a suspension rod
 3 from an outer frame 4 so that vibration due to spinning of the basket
 and rotating of the driving machine, e.g. motor 5, is restrained.
 Motor 5 spins basket 2, and the rotating speed of motor 5 is controlled by
 a control device 6.
 A water valve 8 supplies tap water to water tub 1. A drain valve 7 drains
 cleansing water in the washing machine outside the machine. A lid 9 covers
 a top section of basket 2, and articles, e.g. clothes 10 are loaded into
 basket 2. Spinning basket 2 generates centrifugal force, which works on
 the cleansing water in the basket, so that the cleansing water rises
 toward the inner wall of basket 2. As a result, the surface 11 of
 cleansing water forms a conical shape, in other words, a parabolic line
 from a cross sectional view in a broken line as shown by a broken line in
 FIG. 1.
 In FIG. 2, control device 6 is structured as follows: a controller 12
 comprising a microcomputer controls respective steps of cleansing, rinsing
 and dehydrating based on a mode set by an instruction through a operation
 panel 13. To be more specific, controller 12 controls motor 5 via a motor
 driver 14. Controller 12 also controls water valve 8 and drain valve 7 via
 a power switch 15. A storage 16 stores necessary data for controlling by
 controller 12.
 A rotor-positioning-detector 17 receives a signal from motor 5, and detects
 a position and rotating speed of a rotor, and then outputs the detection
 results to controller 12 and to a clothes-load-determiner 18. Based on the
 data from rotor-positioning-detector 17, clothes-load-determiner 18
 determines an amount of clothes, and outputs the result to controller 12.
 A water level detector 19 detects an amount of water in water tub 1, and
 outputs the result to controller 12.
 A power supply circuit 20, e.g. rectifies and smoothes the commercial power
 21 of ac 100V into a dc voltage, and then powers motor driver 14. Power
 supply circuit 20 also, e.g. lowers that dc voltage to dc 5V to operate
 controller 12. A power switch 22 is coupled to commercial power 21, and
 turns on and off the power.
 Controller 12 controls the spin of basket 2 by controlling motor 5, thereby
 varying the centrifugal force working on the cleansing water in basket 2
 to cleanse the clothes. Controller 12 varies the centrifugal force by
 spinning basket 2 intermittently or varying the spin speed periodically.
 A cleansing operation of the structure discussed above is described
 hereinafter. FIG. 3A shows a variation of spin speed with regard to the
 time lapse when basket 2 is spun intermittently. FIG. 3B shows a variation
 of spin speed with regard to the time lapse when basket 2 is spun by
 varying the spin speed periodically.
 First, the intermittent spin of basket 2 is described with reference to
 FIGS. 3A, 4A and 4B. When basket 2 are halted, clothes 10 is distributed
 in basket 2 almost uniformly, and the surface of the cleansing water stays
 level as shown in FIG. 4A. Then as shown in FIG. 3A, the spin speed is
 increased up to n2 along the time scale from t0 to t1, and the spin speed
 is maintained at n2 until the time=t2.
 When basket 2 spins at n2 spin-speed, centrifugal force works on the
 clothes and cleansing water therein, and the water surface forms a conical
 shape as shown by a broken line in FIG. 4B. If soil attached to the
 clothes has a greater specific gravity than the cleansing water, the soil
 is drawn toward the outside by the spin. Soil having a lower specific
 gravity than the cleansing water is drawn inwardly by the spinning.
 When controller 12 stops powering motor 5 at time=t2, the spin speed of
 basket 2 sharply decreases to 0 (zero) at time=t3, where centrifugal force
 does not work on the clothes nor the cleansing water, i.e. the status
 returns to that shown in FIG. 4A. Driving of motor 5 re-started at
 time=t4, and repeat the procedure discussed above is repeated so that
 basket 2 is spun intermittently. The soil attached to the clothes is thus
 repeatedly pulled and released.
 This intermittent spinning and cleansing power of the detergent causes the
 soil to be readily removed from the clothes. The centrifugal force removes
 the soil from the clothes, and draws some of the soil having a greater
 specific gravity than the cleansing water to the outside, while drawing
 the soil of a smaller specific gravity to the inside. The clothes are thus
 cleansed.
 The variation of spin speed as shown in FIG. 3A varies the centrifugal
 force. The surface of the water in basket 2 varies from a level to a
 conical shape and vice versa as shown in FIG. 4A and FIG. 4B. This change
 moves the clothes from the center to the circumference and vice versa,
 which produces a press-washing effect. This effect contributes to removing
 soil from the clothes.
 Those effects discussed above produce a synergistic effect, thereby
 removing the soil from the clothes efficiently. The clothes receive only
 the force produced by the moving water, and thus remain free from damage
 as well as being entangled.
 Varying the spin speed of basket 2 periodically is another method to
 cleanse clothes, which is described hereinafter.
 As shown in FIG. 3B, the spin speed of basket 2 is increased along the time
 scale from t0 to t5. When the spin speed reaches n2, the speed is
 maintained until time=t6. Then, driving of motor 5 is stopped at time=t6,
 which lowers the spin speed sharply to n1 at time=t7, where a next driving
 operation is started.
 In this case, controller 12 controls power to motor 5 as follows: motor 5
 is powered so that the rotating speed is accelerated from time=t0 to t5,
 and stays at a constant speed from time=t5 to t6. Then the motor is
 stopped at time=t6, which lowers the rotating speed sharply to n1 at t7,
 where the motor is re-powered. This process is stopped so that the spin
 speed of basket 2 rises and falls between n1 and n2.
 This method also produces the same effect discussed previously and shown in
 FIG. 3A. Because the variation of centrifugal force becomes smaller than
 in the previous case, the cleansing power per variation cycle decreases.
 However, frequencies of variation of spin speed are greater than in the
 previous case. This method can thus often gain stronger cleansing power
 per period than the previous method. Either one of the methods shown in
 FIG. 3A and FIG. 3B can be selected as required.
 An operation of the washing machine is described with reference to FIG. 1
 and FIG. 2.
 First, clothes 10 into are loaded basket 2, an then a start-switch (not
 shown) disposed on operation panel 13 is pressed, which drives motor 5 for
 a given time via motor driver 14 based on an instruction of controller 12.
 The operation data of motor 5 during this given time is detected by
 rotor-positioning-detector 17, and transmitted to clothes-load-determiner
 18. Determiner 18 determines load data of the clothes and inputs it to
 controller 12. One of the load determination methods involves e.g.
 transition of rotating speed of motor 5 during the given time based on the
 signals from detector 17, and then the load of the clothes can be
 determined.
 Controller 12 instructs power switch 15 to open water valve 8, which starts
 supplying water to water tub 1. Water-level-detector 19 monitors a water
 level of tub 1, and inputs the report to controller 12. When controller 12
 determines that the water reached a level appropriate to the clothes load,
 controller 12 instructs switch 15 to close water valve 8, and stops
 supplying water. Controller 12 then drives motor 5 via motor driver 14,
 and moves the process to the cleansing step.
 In the cleansing step, controller 12 controls motor 5 to rotate
 intermittently as shown in FIG. 3A. The maximum spin speed n2 of basket 2
 is set based on the water volume, and the maximum spin speed n2 is
 increased at lower water volume. In other words, when tub 1 contains less
 water volume, the smaller load is applied to motor 5, thereby increasing
 the spin speed. When the spin speed is increased, the cleansing water
 won't splash out from the top of the basket, which allows the spin speed
 to increase. The centrifugal force increases at the higher spin speed, so
 that the cleansing power becomes stronger. As a result, a cleansing time
 can be shortened when water is at a low level.
 After the cleansing step is carried out for a given time, drain valve 7 is
 opened for draining the cleansing water. Then, rinsing and dehydrating
 steps are carried out before the washing is completed.
 As such, according to the first exemplary embodiment, the centrifugal force
 due to the spinning of basket 2 forces the cleansing water to run through
 the fibers of clothes, and produces a press-washing effect, whereby soil
 can be removed from the clothes. The clothes are thus cleansed without
 being damage, losing their shape or being entangled.
 Clothes-load-detector 18 gives the data clothes load to controller 12 so
 that controller 12 can vary the water level based on the data. As a
 result, the clothes can be cleansed with an appropriate volume of water,
 which saves water and detergent.
 In this exemplary embodiment, basket 2 having dehydrating holes is
 described as an example; however, a basket doubling as a spin-drier with
 no holes can also produce the same effect.
 Exemplary Embodiment 2
 FIG. 5 is an operational timing chart of a washing machine in accordance
 with the second exemplary embodiment of the present invention.
 The points in the second exemplary embodiment which are different from the
 first embodiment involve the manner of driving basket 2 which doubles as
 the spin-drier. Other structures remain the same as in the first
 embodiment.
 Controller 12 shown in FIG. 2 varies at least respective periods of driving
 and halting of basket 2 in an intermittent driving manner, or varies
 cycles of varying a spin speed of basket 2, based on a water level, the
 clothes load, and the kind of clothes.
 In this embodiment, a method of cleansing is changed responsive to the kind
 of clothes. For instance, a woolen sweater has totally different delicacy
 of fiber and constitution of soil from those of a cotton underwear. When
 mechanical force is impressed to the woolen sweater, fibers are entangled
 with each other, and crinkled, while the cotton is not so delicate as the
 woolen sweater. The cotton underwear is soiled with fatty skin, but the
 woolen sweater is lightly soiled. Accordingly, the woolen sweater does not
 demand so much cleansing power, and is desirably washed free from moving.
 On the other hand, the cotton underwear may be moved during the washing
 and it demands cleansing power.
 FIG. 5 illustrates the specific cleansing ways for these two types of
 clothes. FIG. 5 shows how to control the spin speed of basket 2. Solid
 lines 50 show the spin-speed-control for cleansing the woolen sweater, and
 broken lines 60 show that for the cotton underwear. In the case of the
 woolen sweater, a start-up spin speed varies in a narrow range, and the
 frequency of repetition is controlled to be a small number so that the
 sweater does not move so much. In the case of the cotton underwear, the
 start-up speed varies in a wide range, and the frequency of repetition is
 increased so that the underwear moves well. As such, the manner of varying
 the spin speed of basket 2 produces an appropriate cleansing method for
 the respective clothes.
 Regarding the water level, when the water stays at a lower level, an
 inertia moment of basket 2 containing the clothes and water becomes
 smaller. The spin speed can be thus controlled little by little. The cycle
 of spin speed variation can be shortened in order to increase the
 cleansing power so that the cleansing period can be shortened. The cycle
 of spin speed variation can be thus changed, whereby an appropriate
 cleansing method is produced as well as the cleansing period can be
 shortened.
 Exemplary Embodiment 3
 FIG. 6 is an operational timing chart of a washing machine in accordance
 with the third exemplary embodiment of the present invention.
 In this third embodiment, a point different from the first embodiment is
 the manner of spinning basket 2. Other structures remain the same as in
 the first embodiment.
 Controller 12 shown in FIG. 2 can alternate a spin direction of basket 2.
 An operation of the third exemplary embodiment is described hereinafter.
 The spin speed of basket 2 is controlled as shown in FIG. 6. The Y-axis of
 FIG. 6 represents spin speeds, and a speed of clockwise spin increases
 upwardly from the center, i.e. "0" (zero), while a speed of
 counterclockwise spin increases downwardly from the center "0" (zero).
 First, basket 2 spins clockwise and is the spin is increased in speed, and
 then stopped. Although the spin is halted, the inertia moment of basket 2
 per se keeps basket 2 spinning but with decreasing speed. When the spin
 speed reaches almost "0" (zero), basket 2 is driven to spin
 counterclockwise. Then the spin is increased speed and then stopped. The
 inertia moment of basket 2 keeps basket 2 spinning but with decreasing
 speed. When the spin speed reaches almost "0" (zero), basket 2 is driven
 to spin clockwise. One cycle is thus completed.
 Repeating this cycle moves the clothes in basket 2 in a more dynamic manner
 than the one-way spinning method described in the first and second
 embodiments, which further increases the cleansing power. When basket 2 is
 halted and the spin speed decreases, braking is applied before the spin
 speed reaches "0" (zero), and basket 2 is spun in the reverse direction.
 Then the cleansing power can be still further increased.
 In this case, even if the clothes move in a more dynamic manner, the
 relative locations of clothes with each other are not changed, and
 therefore, the clothes are still free from damage that the conventional
 agitating method causes.
 In this third exemplary embodiment, controller 12 alternates the spin
 direction of basket 2 every spin; however, controller 12 can alternate the
 spin direction after a plurality of spins in the same direction, which
 also produces the same effect.
 Exemplary Embodiment 4
 FIG. 7 is a cross section of a washing machine in accordance with the
 fourth exemplary embodiment of the present invention, and FIG. 8 is a
 block circuit diagram of the washing machine shown in FIG. 7.
 In FIG. 7, a water-guard 23 is disposed on water tub 1. Due to spinning of
 basket 2, cleansing water rises into an annular space between basket 2 and
 water tub 1. The rising water forms a waterfall 24 toward the inside of
 the basket 2, and sprays over the clothes 25 and 26. At this moment, the
 surface 27 of the cleansing water in basket 2 forms a conical shape as
 shown in a broken line. In a lower section of the washing machine, a
 control device 28 for controlling motor 5 is disposed.
 Control device 28 shown in FIG. 8 has the following structure:
 A controller 29 sequentially controls respective steps of cleansing,
 rinsing and dehydrating based on a set mode supplied from an operation
 panel 30. In other words, controller 29 controls motor 5 via a motor
 driver 31. Controller 29 also controls a water valve 8 and a drain valve 7
 via a power switch 32. A storage device 33 stores data necessary for
 controller 29.
 A rotor-positioning-detector 34 receives signals from motor 5, and detects
 a rotor position and its rotating speed. Detector 34 outputs the results
 to controller 29 and a clothes-load-determiner 35. Clothes-load-determiner
 35 determines the load of the clothes based on the data from detector 34,
 and outputs the result to controller 29. A water-level-detector 36 detects
 a water level in water tub 1, and outputs the result to controller 29.
 A power-supply-circuit 37 rectifies and smoothes the commercial power 21 of
 ac 100V into a dc voltage, and then powers motor driver 31.
 Power-supply-circuit 37 lowers that dc voltage and supplies the lowered
 voltage to controller 29 and the like.
 Controller 29 controls a first step and a second step. The first step is to
 spin basket 2 and vary the centrifugal force applied to the cleansing
 water in basket 2, thereby cleansing the clothes. The second step is to
 spin basket 2 and spray the cleansing water rising from between
 water-guard 23 and basket 2 into basket 2, thereby cleansing the clothes.
 The first and second steps are combined so that the clothes can be
 cleansed. Other structures remain the same as the first exemplary
 embodiment.
 An operation of the fourth exemplary embodiment is described hereinafter.
 FIG. 7 illustrates a case where a bulk of clothes are cleansed. When the
 clothes are cleansed, the surface of cleansing water forms a conical shape
 as shown in a broken line in FIG. 7. Clothes 26 are immersed in the
 cleansing water, while clothes 25 are dipped but appear therefrom.
 Centrifugal force works on clothes 26 through the cleansing water, thereby
 cleansing the clothes 26 in the same manner as in the first exemplary
 embodiment. However, clothes 25 cannot be cleansed at this location.
 The second step discussed above is then introduced, i.e. the spinning of
 basket 2 allows the cleansing water to form the waterfall 24 and spray
 over clothes 25 from the location of water guard 23. Since basket 2 spins,
 centrifugal force allows the cleansing water to run through clothes 25,
 thereby cleansing them.
 When a small amount of clothes are loaded, the first step can cleanse the
 clothes, in the same manner as in the first exemplary embodiment.
 How to use the first and second steps properly is discussed hereinafter in
 connection with the operation of the washing machine.
 The clothes are put into basket 2, and then a start-switch (not shown)
 disposed on operation panel 30, which drives motor 5 for a given time via
 motor driver 31 based on an instruction of controller 29. The operation
 data of motor 5 during this given time is detected by rotor positioning
 detection 34, and transmitted to clothes-load-determiner 35. Determiner 35
 determines load data of the clothes and inputs it to controller 29.
 Controller 29 compares an input signal from determiner 35 with the data
 stored in storage device 33 to determine which step, i.e. the first or the
 second step, is desirably taken, and then determines a water level and a
 spin speed. Controller 29 instructs power switch 32 to open water valve 8,
 which supplies water up to the determined level, and then controller 29
 instructs motor driver 31 to drive motor 5 intermittently at the
 determined spin speed.
 As such, the first and second steps can be combined so that various amount
 of clothes can be cleansed with the appropriate amount of water for the
 respective amounts of clothes. The clothes are, of course, cleansed free
 without damage.
 Exemplary Embodiment 5
 FIG. 9 is a cross section of a washing machine in accordance with the fifth
 exemplary embodiment of the present invention.
 In FIG. 9, a washing basket 37 doubling as a spin-drier has a pulsater 38
 disposed rotatably on a bottom section thereof. Motor 5 drives pulsator 38
 or basket 37 via a speed reduction mechanism 39 doubling as a clutch. A
 control device 40 controls a rotating speed of motor 5.
 Control device 40 is structured as shown in FIG. 8 the same as in the
 fourth exemplary embodiment. This fifth exemplary embodiment comprises the
 following three steps:
 Step 1. Spinning basket 37, and varying the centrifugal force working on he
 cleansing water in basket 37, thereby cleansing the clothes;
 Step 2. Spinning basket 37, and spraying the cleansing water into basket
 37, thereby cleansing the clothes;
 Step 3. Spinning pulsater 38, thereby cleansing the clothes. Other
 structures are the same as in the fourth exemplary embodiment.
 An operation of the fifth exemplary embodiment is described hereinafter.
 Responsive to an amount of clothes, one of the above three steps is
 selected, or two or three steps are combined to cleanse the amount of
 clothes. For instance, Step 1 and Step 2 are combined when delicate
 clothes are cleansed, which is same as in the fourth exemplary embodiment.
 When extremely soiled clothes are cleansed, Step 1 and Step 2 are combined,
 and further Step 3, i.e. agitating the clothes with the pulsator, is added
 in order to sufficiently remove soil. In this case, only Step 3 may work,
 but a combination of Step 1 and Step 2 can increase cleansing power and
 decrease damage.
 As such, the fifth exemplary embodiment proves that the washing machine of
 the present invention can accommodate a wide range of clothes, such as
 from a small amount to a bulk of clothes and from delicate clothes to
 extremely soiled clothes.
 As discussed above, the washing machine of the present invention comprises
 a water tub, a washing basket doubling as a spin-drier disposed rotatably
 in the water tub, a driving machine for driving the basket, and a control
 device for controlling the driving machine. The control device varies the
 centrifugal force working on the cleansing water, thereby cleansing the
 clothes. The centrifugal force is generated by spinning the basket.
 According to this structure, the clothes only receive water-moving-force
 generated by the centrifugal force, therefore and, the clothes can be
 cleansed without being from damaged or entangled.
 The present invention also drives the basket intermittently, or varies the
 spin speed thereof thereby varying the centrifugal force dynamically so
 that the surface of the cleansing water varies from a level to a conical
 shape. As a result, soil can be removed effectively.