Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND OF THE INVENTION
.
This invention relates to a~ agitating type washing
machine inwhich an agitating wheel is driven to operate
reciprocally in opposite directions by a drive motor.
In an agitating type washing machine, an agitating
wheel disposed in the center of a bottom of the machlne is
reciprocally rotated within a predetermined angle to effect
intended washing operations, as widely known in the art.
Conventionally, in order to effect such a reciprocal motion,
such an agitating type washing machine includes a gearing,
a link me.chanism, and so on, by way of which rotation of
a motor is transmit~ed to an agitating wheel. Thus, an
agitating type washing machine is applicable particularly
to a large valume washing machine. However, since a mecha-
nism for producing a reciprocal motion therein is complicat-
ed and is thus expensive in cost, it is difficult to employ
such a mechanism for a small washing machine.
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In recent years, in order to introduce an agitating
type into a smallwashin~ machine, an agitating type washing
machine has been proposed in which a motor is directly ~
controlled to run in opposite directions using a timer and
so on to reciprocally rotate an agitating wheel. This
system only necessitates contxol o~ duration of energization '~~
of a motor and thus can be produced advantageously at a
low cost. However, it is disadvantageous in that reciprocal
angular rotations of an agitating wheel will not be held
constant depending upon variations in an amount of the wash-
ing, a voltage of a power supply, and so on, thus preventing
sufEicient perfoxmance of funFtions inherent to the agitat-
~Z. 835
ing type.
In particular, since this system is a timing control- -
ling system which utilizes a timer, an interval of time from
interruption of energization of a motor to actual stopping
thereof is long when the machine is run either without a
load, that is, without any washing, or with a little wash-
ingO On the contrary, when the machine has a large amount
of washing to wash, such washing acts to brake the motor and
hence the motor is stopped in a reduced interval of time.
Accordingly, if an interval of time required to stop a motor
of the machine is determined for no load running of the
machine which provides a maxi.mum interval of time for stop
pin~, then when there is a large amount of washing, some
waste~ul time will appear before the machine is run in the
opposite direction after deenergization of the motor,
resulting in deterioration in efficiency of washing.
Further, since durations of energization of a motor are
held constant, angular rotation of an agitating wheel will
be large when there is a little washing, but on the contra-
ry, when the machine has a large amount of washing, angular
rotation of the agitating wheel will be small. Thus, the
system is disadvantageous in that it presents characteris-
tics which are reverse tG those required for such a washing
machi~e. Accordingly, if it is intended, in such conditions,
to wash a given amount of washing, then when therè is no
water in a washing tank, that s, upon no load running of
the machine, the agitating wheel may rotate in several
rotations and thus there may possibly be a danger of a hand
of a man or the like being caught by the agitating wheel.
A system has a}so been proposed in which a plurality-of
water flows are determinPd in prior in accordancewlthamounts
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of washing and one of such water flows may be selected by
means of a push button switch or the l:ike each time the
machine is used, in order to prevent damage to a cloth of
washing. But, in this system, the amollnt of washing must
be measured accurately each time the machine is used.
However, such measurement is troublesome and hence is actu-
ally effected with the eye, resulting in insufficient
attainment of performance of the washing machine. Besides,
it is also disadvantageous in that, if an operator inadver-
tently forgot to selectively set a water flow, the clothing
might be damaged.
A further system has also been proposed in which a
number of controlled time intervals are provided in accor-
dance with amounts of washing and are changed over to wash
a given amount of washing~ But, this system is also dis-
advantageous in that it is accompanied by a complicated
control.
SUMMARY OF THE INVENTION
The present invention has thus been made in consider-
ation of the circumstances as described above, and it is
an object of the invention to provide an agitating type
washing machine which minimizes variations in angles of
rotation o an agitating wheel due to varying amounts of
washing and which can eliminate a loss of time which may
appear upon changing over of running of the machine from
one to the other direction or vice versa when the machine
has a large~amount of artlcles to wash.
It is another object of the invention to provide an
agitating type washing machine which can control to
attain a constant or uniEorm angle of reciprocal rotation
of an agitating wheel to improve reliability of washing
performances of the machine.
It is a further object of the invention to pro-
vide an agitating type washing machine wherein two different
angles of rotation of an agitating wheel for no load running
and running under a load which are both equal to or less
than 360 degrees are set in prior by means of a controller
composed of an operating processing device, a memory, and
so on, and they are automatically changed over for no load
running and for running under a load in response to an
angle signal detected by means for detecting an angle of
rotation of the agitating wheel so as to prevent a hand
of a man or the like from being caught by the agitating
wheel, wherein, ta~ing notice of a fact that a travel of
the agitating wheel by inertia after deenergization of a
motor i5 substantlally in proportional relationship to an
amount of articles to be washed, the motor is reversed
after the agitating wheel has been stopped so that an
angle of rotation of the agitating wheel which moves by
inertia is made relatively large when there is a small
amount of articles to be washed whereas such an angle is
made retalively small when there is a large amount of
articles to be washed, and wherein a period of time for a
reciprocal motion of the agitating wheel is varied depend-
ing upon an amount of articles to be washed so that the
optimum number of reciprocal motions may be automatically
set in accordance with the amount of articles to be
washed.
According to the present invention, there is
provided an agitating type washing machine in which a
washing drive motor is run reciprocally in opposite direc-
tions to rotate an agitating wheel within a washing tank
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alternatively in one and the other directions to perform
intended washing, comprising a rotational angle detecting
means for detecting an angle of rotation of said agitating
wheel, and control means for controlling said motor in
response to a detection signal from said rotational angle
detecting means, said control means interrupting ener~
gization of said motor when the angle of rotation of
said agitating wheel reaches a predetermined value, said
control means controlling said motor to run in a reverse
direction after rotation of said agitating wheel by inertia
in one direction has been almost stopped.
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BRIEF DESCRIPTION OF THE DRAWINGS
.
Fig. 1 is a sectional view showing an embodiment of
an agitating type washing machine of the present invention;
Fig. 2 is a sectional view taken along the line A-A of
the Fig. l;
Fig. 3 is a schematic diagram showing a ccntrol system
for the arrangement of Fig. l;
Fig. 4 is a flow chart showing the operation oE the
arrangement of Fig~ 1 and particularly of the control system
of Fi~. 3;
Fig~ 5 is a flow chart showing another manner of Collt-
rol;
Fig. 6 is a flow chart showing a further manner of
control;
Fig. 7 is an enIarged perspective view showing an
improved reduction gear mechanism;
Fig. 8 is a diagram showing a circuitry for the wash-
ing machine;
Fig. 9 is a diagram showlng the operation of the
motor;
Fig. 10 is a sectional view showing another embodiment
of the washing machine;
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Fig. 11 is a sectional view taken along the line A~A
of Fig. 10;
Fig. 12 is an enlarged partially cutaway perspective
view showing a rotation angle de~ector;
Fig. 13 is a sectional view showing a further embodi-
ment of the washing machine;
Fig. 14 is a sectional view taken along the line A-A
of FigO 13;
Fig. 15 is a perspective view showing another embodi-
ment of a rotation angle detector;
Fig. 16 is a sectional view similar to Fig. 13;
Fig. 17 is a sectional view taken along the line A-A
of FigO 16; and ,
Fig. 18 is an enlarged partially cutaway view showing
a rotation angle detector secured to the motor shaft.
DETAILED DESCRIPTION OF THE EMBODIMENT
_ _ ~ _ _ _ _
An embodiment of the present invention will now be
described with reference to the accompanying drawings.
Referring to Figs. 1 and 2, a washing tank 2 is secured~
within the outer housing 1 of a washing machine and articles
are washed in the washing tank 2. ~ main shaft 3 is mounted
water-tight in the center of a bottom of the washing tank 2
and is supported for rotation by~means of a main shaft bear-
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33S
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ing 4. An agitating wheel 5 is mounted on the rnain shaft 3within the washing tank 2, and a pulley 6 is mounted at a
bottom end of the main shaft 3 and has a plurality of de-
tection holes 7 for detection of a rotational angle of the
agitating wheel 5 perforated in a pred,_termined spaced
relationship along a circular line therein tFig. 2~.
A rotational angle detector 8 includes a light emitting
section 9 and a light receiving section 10 which receives,
at a position of a detection hole 7 of the pulley 6, a beam
of light projected from the light emitting section 9 and
produces a number of pulse signals corresponding to an angle
of rotation of the pulley 6 and hence an angle of rotation
of the agitating wheel 5. A washing machine drive motor 11
is mounted on the bottom in the outer housing 1. Another
pulley 12 is mounted on the motor 11. A belt 13 inter-
connects the pulleys 5 and 12. Rotation of the motor 11 is
thus transmitted to the agitating wheel 5 by way of the
pulleys 6 and 12 and the belt 13.
Fig. 3 shows a control system for the arrangement of
Figs. 1 and 2, and a control circuit 14 includes a memory
15, an operating processing device 16, an input control 17
and an output control 18. A power source is connected to
the control circuit 14 by way of a switch 19. Detection
signals representative of an angle of rotation of the
agitating wheel S detected by the rotational angle detector
8 are input~ted to the control circuit 14 through the input
control 17 and are operated and processed by the memory 15
and the operating pxocessing device 16. A signal produced
as a result of such processing is applied as a control
signal to the motor 11 through the output control 18 so as
to rotate the motor 11 in a clockwise or counterclockw}se
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direction in accordance with the output signal.
Fig. 4 is ~flow chart which indicates operations of
the arrangement and particularly of the control system
thereof as described above~ ~ step 100 is a rotational
direction flag setting step at which a flag is set which
represents a running direction of the motor 11, and next
step 101 is a rotational angle setting step for setting an
angle of rotation of the aaitating wheel 5 (an angle over
which the motor is energized~. Thus, at step 101, the
number of pulses N corresponding to an angle of rotation is
set, and this value is stored in a register X at next step
10~. Subsequent step 103 is a rotational direction dis-
criminating step for discriminating a rotational direction
o~ the motor 11, and step 106 is a counter step ~or count-
ing an angle of rotation of the agitating wheel 5 (the
number of pulses from the rotational angle detector 8), and
the count is inputted to a register T. Step 137 is a com-
paring step at which the angle of rotation of the agitating
wheel 5 is compared with the preset value N in order to
determine if the former reaches the latter, step 109 is a
stopping discriminating.step at which it is discriminated
that pulse signals from the rotational angle detector 8
are terminated and hence the agitating wheel 5 is stoppted,
and step 110 is a rotational direction setting step at which
a direction of rotation of the motor is set.
Operations of the arrangement as described above will
now be described. At first, washing or articles to be
washedj water and a cleanser are put into the washing tank
2, and the power switch 19 is switched on. At step 100,
the flag F is set to I =o as ~o provide for rotation o- th~
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motor in a clockwise direction, and at next step 101, a
pulse nlImber N representative of an angle over which the
agitating wheel 5 is to be rotated is set and the value is
put into the register X at subsequent step 102. Since F=l
at the rotation direction discriminating step 103, control .:
advances to step 104 so that the motor 11 is rotated in the
clockwise direction thereby to rotate the agitating wheel 5
in the clockwise direction through the pulley 6 to thus
begin washing operations. At the same time~ pulse signals
are produced from the rotational angle detector 8. The
pulse signals are counted at the counter step 106 and are
placed into the T register, and at next step 107, contents
of the register T and the registar X are compared with each
other~ and if TX, control goes back to step 103 to continue
clockwise .rotation of the motor 11. On the contrary, if
T~X, then the motor 11 is deenergized at step 108. At next
step 109, it is d~tected that there is no pulsP signal
received from the rotational angle detector 8, thereby con-
firming stopping of the agitating wheel 5 which has continu-
ed its rotation due to an inertia force thereof. Then,
since F=l at step 110, control advances to step 11 at which
the flag F is set F=0 and then returns to step 103. Since
F-0 now, control advances to step 105 at which the motor 11
initiates its rotation in the counterclockwise direction.
The program will now proceed in a similar manner as for the
clockwise rotation of the motor 11. In this way, the agi-
tating wheel 5 will repeat its reciprocal rotational move-.
ment to continue washing operations until the power switch
19 is switched:off.
Fig. 5 is a flow chart showing another manner of
control. In this figure, refPrence numerals 100 to 113
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designate the same step as those of Fig. 4 and reference
numeral 120 designates a counter step, and reference
numerals 122 and 123 designate angle comparing steps at
which an angle of rotation before the agitating wheel 5 is
stopped is compared with a reference angle of rotation.
Further~ reference numerals 124, 125 and 126 designate each
an operating step at which the reference angle is added to
or subtracted from the angle of rotation of the agitating
wheel 5, and a result of any such operation i5 placed into
the X register so as to control energization of the motor
11 to coincide the angle of rotation with the reference
angle or rotation.
Upon starting a washing operation, artilcles to be
washed, water and a cleanser are charged into the washing
tank 2, and the power switch 19 is switched on. Then, at
step 100, the flay F is set to 1 for clockwise rotation of
the motor 11, and at step 101, the number N of pulses cor-
responding to a reference angle of rotation of the agitating
wheel 5. The value X is stored in the X register at step
102. At step 103, it i5 determined if the motor 11 is to
rotate in the clockwise or counterclockwise direction, and
if F=l here, it is determined that the motor 11 is to rotate
in the clockwise direction. As a result, at subsequent step
104, the motor 11 thus begins to rotate in the clockwise
direction. The pulley 6 is thus rotated by the motor 11 to
rotate the agitating wheel 5 whereupon a pulse signal is
produced from the rotational angle detector 8. At next step
106, the pulse is counted by the counter, and the count is
put into the T register. At step lQ7, the contents of the
T register and the X register are compared with each other,
and if T<X, then control qoes back to step 103 to continue
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the clockwise rotation of the motor 11. On the contrary,
if T>X, that is, when the angle or clockwise rotation of
the agitating wheel 5 comes equal to or exceeds the refer
ence angle of rotation, control advances to step 108 at
which the motor 11 is deenergized. The motor 11 thereafter
continues its clockwise rotation due to its inertia, and
meanwhicl at step 120, pulse signals are further counted
and the count is put into the T register. At step 109, it
is determined from the presence or absence of pulse signals
if the agitating wheel 5 is actually stopped or not, and
when the agitating wheel 5 is not yet in a stopped condition,
then control goes back to step 120 to continue a counting
operation of such pulse signals. When i~ is determined that
the agitating wheel 5 is in a stopped condition, then ~ero
is put into the X register at step 121. At next step 122r
the pulse number N representative of the reference angle
of rotation which is preset at step 101 and the pulse number
T representative of the angle of actual roiation are compar-
ed with each other, and when T>N, control goes to step 124
which is an operation processing step at which the number
of pulses (T-N) corresponding to an angle by which the
actual angle of rotation exceeds the reference angle is
calculated, and a value of the reference rotational angle
pulse number N less (T-N) is put into the A register. On
the other hand, when T=N, then control goes from step 123
to step 136 at which the pulse number N is placed into the
X register. Further, if T<N from some reason, then control
goes from step 123 to step 125 at which the shortage pulse
number (N-T) is calculated, and the value (N-T) added by the
pulse number N is placed into the X register. Then, at next
step 110, it is determined that F=l, and accordingly control
goes to step 1ll at which the Fotational dlrection flag F
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for the motor 11 is reset to zero. Then at next step 113,
the T register is also reset, and contxol goes back to step
113. Since F=0 now, contorl advances Erom step 103 to step
105 at which the opposite counterclockwise rotation of the
motor 11 is star~ed to rotate the agitating wheel 5 in the
counterclockwise direction. The program will thereafter
proceed in a similar manner as for the clockwise rotation
of the motor 11. As a result, the agitating wheel 5 repeats
reciprocal rotations until the power switch 19 is switched
off to complete washing of the articles to be washecl.
Thus, in the present embodiment, a surplus or cLeficit
of an angle of actual rotation relative to a reference angle
of rotation of the agitating wheel 5 in a rotation in one
o~ clockwise and counterclockwise directions is compensated
in a rotation of the same in the other direction, as describ-
ed above. As a result, angles of reciprocal rotation of the
agitating wheel 5 in opposite directions are held substan-
tially uniform, thereby eliminatiny irregular washing per-
formances to improve reliability of washing performances of
a washing machine.
Fig. 6 is a flow chart showing a further embodiment of
the present invention in which an angle of rotation of the
agitating wheel during no load running of the machine is
smaller than that during running under a load, and changing
over between no load running and running under a load is
effected automatically in response to a detection signal as
described above. In the embodiment, the motor is reversed
after the agitating wheel has stopped, an angle or rotation
of the agitating wheel is held in any case less than 360
degree~ including rotation by inertia, and a period of time
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required for a reciprocal motion of the agitating wheel is
changed in accordance with an amount of articles to be wash-
ed, utilizing a difference in rotation by inertia.
Referring to Fig. 6, step 200 is a step at which a
no load running flag is set in order that a washing running
may be effected by all means under no load to enable detec-
tion of a load to be effected upon starting of running of
the machine. Step 201 is a step at which a rotational
direction flag for the motor 11 is set. Step 202 is a step
for setting an angle of rotation of the agita~ing wheel for
no load rl~nning (running in a condition in which there is
no water nor any artilce in the washing tank 2), and thus
at step 202, the number of pulses N~ is set corresponding
to an angle of rotation of the agitating wheel. Then at
ne~t step 203, the value Nl is placed into the register Xl.
Step 204 is a step for setting an angle of rotation of the
agitating wheel during running under a load, and at step
204, the number of pulses N2 is set, which value is input-
ted, at step 205, into a register X2 in a similar manner as
in the case of no load running~ Step 206 is a step at which
a direction of rotation of the motor 11 is chan~ed over.
Step 209 is a counter step a~ which an angle of rotation
of the agitating wheel 5 tthe number of pulses) upon energi-
zation of the motor 11 is counted, and at step 214, an angle
of rotation of the agitating wheel 5 is counted while the
agitating wheel 5 rotates by its own inertia after the motor
11 has been deenergized, such counts being placed into the
T register; a sum total of both counts represents an angle
or actual rotation of the agitating wheel 5. Step 210 is~
a load changing over ~tep at which an angle of rotation of
the agitating whe~l 5 (duration oL energization of the
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motor 11) is changed over between for no load running and
for running under a load, and at steps 211 and 212, angles
of rotation are compared~ Step 215 is a stopping discrimi
nating step at which it is discriminated that the agitating
wheel S has been stopped upon the basis of the fact that
there is no pulse signal received from the rotational angle
detector 8, and s~ep 218 i9 a step at which a direction of
rotation of the mo~or 11 is set. The r~o load running
rotational angle set value Nl and the load running rota-
tional angle set value N2 have a relation Nl<N2, and the
set value N} is determined such that the angle of rotation
of the agitating wheel 5 including rotation by inertia upon
no load running is smaller than 360 degrees and is greater
than an angle of rotation corresponding to the rotation
angle set value N2 including the rotation angle of the
agitating wheel 5 by inertia and on the other hand, the set
value Nl is determined such that it is smaller than the
angle of rotation corresponding to the set value N2 includ-
ing the anyle of rotation of the agitating wheel 5 including
rotation by inertia upon running under a load~ Further,
the set value N2 is determined such that the angle of rota
tion of the agitating wheel 5 including rotation by inertia
UpQn running under a load does not exceed 360 degrees.
Now, operations of the arrangement as described just
above will be described. At first, articles to be washed,
water and a cleanser are put into the washing tank 2 and
the power switch 19 is switched on. Then, at step 200, the
no load rllnning flag Fl is set to 1, and at step 201, the
running direction flag F2 is set to l-~for clockwise rota~
tion). At step 202, the no load running rotational angle N
of the agitating wheel 5 ~duration of energizatlon of the
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-16~ 35
motor 11) is set, and at step 203, the value Nl is put into
the register Xl. At next step 204, the load running rota-
tional angle N2 (duration of motor energization) is set,
and at step 205, the value N2 is put into the register X2,
thus completing initialization of the system.
Thenl control goes to step 206, at which F2=l is
determinea so that control further goes to step 207 at which
the motor 11 is rotated in the clockwise direction to rotate
the agitating wheel 5 clockwise, thus starting a washing
operation. At the same time at step 209, an angle of rota-
tion of the agitatingwheel 5 is detected by means of the
rotational angle detector 8 and a pulse signal is added to
the register T from the detector 8. At the load changing
over step 210,Fl-l is determined, and hence, control goes
to the no load running rotational angle. discriminating step
211 at which the count of the register T i5 compared with
the count of the register Xl. Here, when T<XI, that is,
when the agitating wheel 5 does not yet reach the preset
angle, control goes back to step 206 to continue the clock-
wise rotation of the motor 11. On the contrary, when ~_X~,
that is, when the agitating wheel 5 reaches the present
angle, control goes to step 213 at which the motor 11 is
deenergized. As a result, the agitating wheel 5 enters
rotation by inertia while an angle over which the agitating
wheel 5 further rotates is added to the register T at step
214. Such counting is continued until the agitating wheel
5 is stopped. The angle of rotation of the agitating wheel
5 by inertia is large when there are a small amount of
articles to be washed, and on the contrary when there are
a large amount of articles to be washed, it is small. Thus,
the angle of rotation of the agitating wheel 5 varies
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17- ~2~35
substantially in proportional relationship to the amount of
articles to be washed, and as a result, the number of reci-
procal motions of the agitating wheel 5 per minute varies
automatically.
Then at next stopping discriminating step 215, it is
confirmed that the agitating wheel 5 has been stopped upon
the basis of the fact that there is no more pulse signal
received from the rotational angle detector 8, and at step
216, a load condition is determined. Since now a washing
operation is proceeding and the machine is actually under
a load, an anyle of rotation by inertia is relative:Ly small
and thus T<X2. As a result, it is determined that the . .
machine is running under a load (that is, during washing) at
step 216, and at next step 217, the flag Fl is reset to zero.
Since F2=l at subsequent motor rotational direction setting
step 218, control goes to step 219 at which the flag ~2 iS
cleared, and at step 221, the register T is reset to zero
whereafter control goes back to step-206. Since now F2=0
at step 206, control goes to step 208 at which the motor 11
begins its counterclockwise rotation to rota~e the agitating
wheel 5 in the counterclockwise.direction. At step 209,
the number of pulses corresponding to an angle of rotation
of the agitating wheel 5 is put into the register T, and
then, since Fl-0 at next step 210, control goes to step 212
at which, since the w~shing machine is now under a load, the`
machine is rotated over a greater angle than during no load
running. The program will thereafter proceed in a similar
manner as fox the clockwise rotation of the machine~ Thus,
the agitating wheel 5 will repeat its reciprocal motions .
to continue its washing operations until the power switch
15 is switched off.
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-18~ 35
Thus, the washing machine positively utilizes rotation
by inertia of an agitating wheel such that the agitating
wheel is rotated in a reverse direction after rotation
thereof in one direction has been stopped and, in consider- -
ation of a difference in rotation ~y inertia depending upon
an amount of articles to be washed, a period of time for a q
reciprocal motion of the agitating wheel is changed in
accordance with an amount of artilces to be washed so as to
cause water flows appropriate for the amount of such arti-
cles to be automatically produced, thereby preventing damage
to cloths of such articles. Further, an anyle of rotation
of the agitating wheel or duration of energization of a
motor during no load running in which relatively large
rotation by inertia is involved is made smaller than that
duriny running under a load while changing over between no
load running and running under a load is automatically
effected in response to a detection signal from a rotational
angle detector, whereby an angle or actual rotation of the
agitating wheel can be controlled less than 360 degrees.
Accordingly, a hand of a man or the like can be prevented
from being caught by the agitating wheel and articles being
washed are prevented from being entanyled with each other.
In this way, a washing machine of a high safety and of a
high quality can be provided.
,~
However, in the e~bodiments as described abo~e, the
duration of energization of the motor ~or the clockwise
rotation is equal to that or the counterclockwise rotationO
Accordingly, in the case of a washing machine which includes
reduction gears, it is disadvantageous in that force trans-
mitting portions of power input and output sides (contact
portionsj are normally limited to respective particular
2~ 35
ranges and hence wear at such portions is relativ~ly greater
than that at other portions, thus shortening the life of the
reduction gear mechanism.
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An embodiment as shown in Figs. 7 to 9 has been made
in consideration of this regard, and thus in this embodiment,
an angle of rotation of an agitating wheel in one direction
is differentiated from that in the opposite direction,
thereby improving the reliability of a reduction gear mecha~
nism. Referring to Fig. 7 which is an enlarged view showing
part of the main shaft 3 shown in Fig. 1, reference numeral
20 designates a brak~ band fitted on the main shaft 3 and
adapted to brake the same, and 21 a stop fixed to the bottom
of the washing tank 2 and positioned to be abutted by lugs
20a and Z0b at opposite ends of the brake band 20.
Fig. 8 shows a circuit construction of a washing
machine of the present embodiment. In Fig. 8, a power
source contact 22a is controlled by a timer 22. Reference
numerals lla and llb denote contacts for clockwise and
counterclockwise rotation of the motor 11, respectively,
reference numeral 23 denotes a power terminal, and 24 a
capacitor. FigO 9 isa diagram showing operations of the
motor 11, and during a particular period of time To between
points of time to and tl t the power source contact 22a is
held in contact with the contact lla for clockwise rotation.
On the other hand, during a subsequent particular period
of time Tl be~ween points of time tl and t~, the power
source contact 22a is in its neutral position without being
contacted with any of the cont cts lla and llb. During a
next period of time T2 between points of time t2 and t3,
the power source contact 22a is in contact with the contact
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llb for counterclockwise rotation, and during a following
period of time T3 between points of time t3 and t4, the
power source con~act 22a is again in its neutral position.
Such a sequence of operation~ will repeat during an intended
washing period of time T. Accordingly, the motor 11 is
rotated alternately in the clockwise and counterclockwise
directions with the predetermined stopped time periods Tl
and T3 interposed therebetween~ It is to ke noted here that
the time periods To and T2 for clockwise and counterclock-
wise rotation are determined such that the angle of rotation
of the agitating wheel 5 is limited to a range equal to or
less than 360 degrees with such factors taken into consider-
ation as washing capacity, a rotational frequency of the
motor 11, a reduction ra~io between the motor pulley 12 and
the agitator pulley 6, and so on, and a relation between the
time periods ~or the clockwise and counterclockwise rota-
-tions is set to To<T?. Thus, the timer 22, its and other
contacts 22ar lla and llb, brake band 20 and stop 21 co-
operate to constitute a control device.
With the washing machine constructed as described
above, articles to be washed, water and some cleanser are
at first charged into the washing tank 2, and the timer 2~
is set to a predetermined time T whexeafter the power source
is connected. Then~ during the predetermined time period
To between time points t~ and tl, the motor 11 xotates in
the clockwise direction. This clockwise rotation of the
motor 11 is transmitted via the motor pulley 12, belt 13
and agitator pulley 6 to the main shaft 3 to rotate the
agitating shaft 5 in the clockwise direction thereby to
rock the articles in the cleanser-containing liquid within
the washing tank 2. Then, during the subse~uent predeter-
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mined time period Tl be~ween time points t1 and t2, themotor 11 is held in a deenergized condition and as a result,
although the agitating wheel 5 continues its rotation some-
what by inertia, its rotational speed drops gradually and it
comes to stop finally. Mowever, if the angle of rota~ion ;
of the agitating wheel 5 approaches 360 degrees before it
comes to stop, the lug 20a of the brake band 20 comes into
abutment with the stop 21. As a result, the agitating wheel
5 is stopped at an angle of rotation less than about 360
degrees while the main shaft 3 is braked thereby due to a
slip appearing between the main shaft 3 and the brake band
20. Then, duriny the next predetermined time period T2
between points of t.ime t2 and t3/ the motor 11 is rotated
in the counterclockwise direction, and the counterclockw:ise
rokation of the motor 11 rotates the agitating wheel 5 in
the counterclockwise direction thereby to rock the articles
in the counterclockwise direction reverse to that as de-
scribed above. During the subsequent time period T3 between
time poin~s t3 and t4, the agitating wheel 5 continues its
rotation due to its inertia, but dec~easing its sp~ed
gradually until it finally stops. In the meantime, when
the angle orrotation reaches a predetermined angular po~
tion near 360 degrees, the other lug 2Qb of the brake band
20 comes into abutment with the stop 21. As a result, the
agitating speed 5 is blocked and thus stops at such an
angular posit on less than 360 degrees. Since duration of
energization of the motor 11 for counterclockwise rotation
is made longer than that for clockwise rotation, contact
portions between.the speed reduction pulley 6 and the belt
13 and between the motor pulley 12 and the belt 13 will
gradually vary each time reciprocal rotational motion of
the motor 11 is transmitted to the agitating wheel 5.
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Such a sequence of operations wil:l repeat during ~he
period of time T preset by the timer 22, and thus articles
are rocked within an angle of rotation substantially within
360 degrees alternately in the clockwise and counterclock-
wise directions in the cleanser-containing liquid. In a
conven~ional washing machine in which an agitating wheel
rotates alternately in the clockwise and counterclockwise
directions to effect agitati.ng actions but in several rota-
tions, still there is a danger that~ if a hand of a man
should touch the agitating wheel in error, then it might be
caught thereby, and such a phenomenon may also appear that
articles being washed be entwined around the agitating wheel.
On the contrary, according to the embodiment as described
just above, the agitating wheel 5 is not rotated beyond an
angle of 360 degrees, and hence articles are not entwined
around the agitating wheel 5, assuring excellent results
of washing with minimized irregularities. Besides, should
a hand of man touch the agitating wheel 5 in error, it will
hardly be caught thereby since it changes its rotating
direction before completion of one complete rotation,
assuring sufficiently safe washing operations.
Now, description will be given of another example o~
detecting means which can be applied to the present .
invention.
While an example is shown in Fig. 1 in which the pulley
6 has a plurality of holes 7 perforated therein for detec-
tion of an angle of rotation and:is interposed between the
light emitting means 9 above and the light receiving means
10 below~ alternatively an independent detection disk 25
may be provided ~t an ~nd portlon of the main sh~ft 3, as
-23~ 35
shown in Figs. 10 to 12.
Referring to Figs. 10 to 12, the detection disk 25 is
made of a magnetic material such as iron which has a alter-
nate teeth 26 and recesses 27 formed i.n a predetermined
spaced relationship around an outer periphery thereof for
detecting an angle of rotati~n of the agitating wheel 5.
The detection disk Z5 is secured to the main shaft 3.
Reference numeral 8 designates an angle detector which in-
cludes a magnetic resistor element 9 and a permanent magnet
10 fixedly disposed in a spaced relationship by a predeter-
mined distance from each other and also from a radial end
of the detection disk 25. A pxedetermined voltage is
applied to the magnetic resistor element 9. As commonly
known in the art, the magnetic resistor Plement 9 has an
electric resistance which varies in response to the inten-
sity of a magnetic field, and the direction of a magnetic
field varies in response to presence and absence of a recess
27 of the disk 25. As a result, as the detection disk 25
which is a magnetic member is rotated, an electric current
flowing through the magnetic resistor element 9 varies each
time a recess 27 passes thereby. . In the present arrangement, ..
the electric current is processed electrically such that,
as the detection disk 25 is rotated, pulse-like electric
signal~ corresponding to an angle of actual rotation of
the agitating wheel 5 are detected.
Reference is now made to FigsO 13 to 15 which show
a further example of detecting means. The detecting means
includes a similar detectio~ disk 25 to that of Figs. 1:0
to 12, but this detection disk 25 has a side wall section 26
integrally formed to extend substantially perpendicularly in
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-24~ 3~
a downward direction from an outer circumferentiaI end
thereof. The side wall section 26 of the detection disk 25
has a plurality of detection r~cesses 27 formed in a cir-
cumferentially equally spaced relationship therein to pro
vide a comb like configuration to the side wall section 26.
Reference numeral 8 denotes a ro~ational angle detector
mounted on the bottom of the washing tank 2 and including
a light emittimg element 9 and a li~ht receiving element 10
disposed in opposing relationship adjacent opposite sides
of the side wall sec~ion 26. Thus, when a detec-tion recess
27 is positioned between the light emitting element 9 and
the light rece.iving element 10,light from the light emitting
element 9 is received by the light receiving element 10.
On the ~ontrary, when a portion of the side wall section 26
other than the det~ction recesses 27 is positioned between
the light emitting element 9 and the light receiving element
10, light from the light emitting element 9 is interrupted
thereby. Accordingly, pulse signals which correspond to
an angle of rotation of the agitating wheel S are outputted
from the light receiving element 10.
It is to be noted that the rotational angle detector
8 o the example described just above may alternatively be
constituted such that the detection disk 25 is made of a
magnetic material such as, for example, iron and the light
emitting element 9 and the light receiving element 10 are
replaced by a Hall element and a permanent magnet, respec-
tively. In particular, a predetermined voltage is applied
to the Hall element 9, and as commonly known in the art,
an electric current flowing through the Hall element 9
varies in response to the intensity of a magnetic field
due to a Hall effect, and the direction of a magnetic
field varies Ln response to the presence and absence of a
-` ~Z~~83~i
-25-
recess 27 of the disk 25. As a result, as the detection
disk 25 which is a magnetic member is :rotated, an electric
current flowing through the Hall eleme:nt 9 varies each time
a recess 27 passes thereby. The electric current is pro-
cessed elec~rically such that, as the detection disk 25 is
rotated to rotate the side wall 26, pulse-like electric
signals corresponding to an angle of actual rotation of the
agitating wheel 5 are detected.
It is to be mentioned that an angle of rotation can
be detected similarly if the Hall element 9 is otherwise
repalced by a magnetic resistor element which has an elect-
ric resistance which varies in response to the intensity of
a magnetic field.
It is al..o to be mentioned that, while only the
examples of detecting means which involve detection of an
angle of rotation of the agitating wheel 5, an angle of
rotation of the agitating wheel can otherwise be detected
indirectly from detection of the number of rotation of the
agitating wheel. Such an example is illustrated in Figs~ 16
to 18. In this arrangement, a reduction ratio which is
determined by a pulley 6 and a motor pulley 12 is almost
10:1 so that one complete rotation of a motor will rotate
an agitating wheel 5 by an angle of about 36 degrees~
In the arrangement of Figs. 11 to 18, a motor 11
having a high rigidity includes a rotation detector 30
disposed therefor.for detecting the number of rotation of
the motor. The rotation detector 30 includes a cylindrical
permanent magnet 31 fixedly mounted on a lower end 29' of
a motor shaft 29, a generating coil 32 wound in a cylindri-
3~
-25~
cal form around an outer periphery of the permanent magnet
31 with a predetermined air gap left therebetween, and
a magnetic shield member 33 disposed in the air gap between
the permanent magnet 31 and the generating coil 32 to parti
ally in~errupt a magnetic field of the permanent magnet 31.
Since~ in the rotation detector 30 having such a construc
tion as described abovel rotation of the motor shaft 29 will
rotate the permanent magnet 31 fixedly mounted thereon, a
sinusoidal electric current is induced in the generating
coil 32 in synchronized relationship to rotation of the
permanent magn~t 31, as commonly known in the art. The
sinusoidal electric current is processed electrically so
that, as the motor 11 rotates, pulse-like electric signals
are outputted in synchronism therewith. In this way, the
rotation detector 30 is disposed in the motor 11 in which
most parts are made of metal materials so that rotational
conditions of the motor can be detected directly. This
construction thus assures high accuracy in assembly and
high workability and enables accurate and stabilized
detection of rotational conditions of a motor.
The ro~ation detector 30 which detects the numbe~,r of
rotations of the motor ll may comprise a cylindrical per-
manent magnet secured to the lower end of the motor shaft
27 and magneto-resistor elements which are disposed around
the permanent magnet in spaced relationship therewith. The
elements serve as detectors which change the resistivity
with the changes in the magnetic strength of the permanent
magnet.
In such an arrnagement the changes in magnetic strength
of the permanent magnet corresponding to the rotation of the
, ~
~2~ 5
-27-
motor 11 is detected by the magnetic resistor element and
is subjected to electrical processing to provide pulse like
electrical signals in synchronism with the rotation of th~
motor 11.
Alternatively Hall elements may ble disposed in lieu
of the magnetic resistor elements. In this arrangement,
the ~all elements detect the changes in the magnetic
sterngth corresponding to the rotation of the motor 11 to
generate pulsa like electrical signals in synchronism with
the rotation of the motor 11.
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