CA1210835A - Agitating type washing machine - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

In an agitating type washing machine a washing drive motor is run reciprocally in opposite directions to rotate an agitating wheel within a washing tank alternately in one and the other directions to perform intended washing.
The agitating type washing machine comprises 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. The control means inter-rupts energization of said motor when the angle of rotation of said agitating wheel reaches a predetermined value and runs the motor in a reverse direction after rotation of said agitating wheel by inertia in one direction has been almost stopped.

Description

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BACKGROUND OF THE INVENTION
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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 e'.~, - 5a -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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~ ' .~, -6- ~2~835 BRIEF DESCRIPTION OF THE DRAWINGS
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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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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 .

-12- ~Z~35 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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-13~ 35 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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-15- ~2~ 5 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.

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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 -20- ~ 3~

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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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 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-

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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 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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Claims (27)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An agitating type washing machine in which a washing drive motor is run reciprocally in opposite directions to rotate an agitating wheel within a washing tank alternately 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 energization 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.

2. An agitating type washing machine according to claim 1, in which said control means controls in response to a detection signal from said rotational angle detecting means such that the angle of rotation of said agitating wheel including rotation by energization of said motor and rota-tion by inertia is kept substantially constant whether during running under load or during no load running.

3. An agitating type washing machine according to claim 1, in which said control means controls such that an angle of rotation of said agitating wheel by energization of said motor during running under no load is made smaller than that during a load running and that changing over between run-ning under a load and no load running is automatically effected in response to a detection signal from said rotational angle detecting means.

4. An agitating type washing machine according to any one of claims 1 to 3, in which said control means controls rotation of said agitating wheel to an angle equal to or less than 360 degrees including rotation by energization of said motor and rotation by inertia.

5. An agitating type washing machine according to any one of claims 1 to 3, in which said rotational angle detect-ing means includes a pulley for transmitting a driving force of said washing drive motor to said agitating wheel, said pulley having a plurality of detection holes perforated therein in a spaced relationship from each other by a pre-determined distance, and a light emitting means and a light receiving means disposed in opposing relationship with one of said detection holes positioned therebetween.

6. An agitating type washing machine according to claim 3, in which said rotational angle detect-ing means includes a detection disk secured horizontally to a rotary shaft of said agitating wheel and having a plura-lity of detection holes formed in a predetermined spaced relationship in a planar portion thereof, and detecting means disposed in an opposing relationship with one of said detection holes of said detection disk interposed there-between.

7. An agitating type washing machine according to claim 6, in which said last-mentioned detecting means includes a light emitting element and a light receiving element disposed in an opposing relationship to each other.

8. An agitating type washing machine according to claim 3, in which said rotational angle detect-ing means includes a detection disk made of a magnetic material having a plurality of recesses formed in an equally spaced relationship along an outer circumference thereof, said detection disk being rotated in response to rotation of said agitating wheel, and detecting means disposed at a position corresponding to the recessed portion of said detection disk.

9. An agitating type washing machine according to claim 8, in which said last-mentioned detecting means includes a light emitting element and a light receiving element disposed in an opposing relationship to each other.

10. An agitating type washing machine according to claim 8, in which said last-mentioned detecting means includes a magnetic resistor element and a magnet disposed in an opposing relationship to each other.

11. An agitating type washing machine according to claim 8, in which said last-mentioned means includes a Hall ele-ment and a magnet disposed in an opposing relationship to each other.

12. An agitating type washing machine according to claim 8, in which said detection disk has an outer circumferen-tial end bent substantially perpendicularly thereto to form a side wall in which a plurality of recesses of a predeter-mined width are formed in an equally spaced relationship from each other.

13. An agitating type washing machine according to claim 3, in which said rotational angle detecting means includes a magnet which rotates in response to rotation of said agitating wheel, and a detector disposed adjacent said magnet.

14. An agitating type washing machine according to claim 13, in which said magnet is integrally formed on a rotary shaft of said motor.

15. An agitating type washing machine according to claim 13, in which said detector is a generating coil.

16. An agitating type washing machine according to claim 13, in which said detector is a magnetic resistor element.

17. An agitating type washing machine according to claim 1, in which said rotational angle detecting means includes a detection disk secured horizontally to a rotary shaft of said agitating wheel and having a plurality of detection holes formed in a predetermined spaced relationship in a planar portion thereof, and detecting means disposed in an opposing relationship with one of said detection holes of said detection disk interposed therebetween.

18. An agitating type washing machine according to claim 17,in which said last-mentioned detecting means includes a light emitting element and a light receiving element disposed in an opposing relationship to each other.

19. An agitating type washing machine according to claim 1, in which said rotational angle detecting means includes a detection disk made of magnetic material having a plura-lity of recesses formed in an equally spaced relationship along an outer circumference thereof, said detection disk being rotated in response to rotation of said agitating wheel, and detecting means disposed at a position corres-ponding to the recessed portion of said detection disk.

20. An agitating type washing machine according to claim 19, in which said last-mentioned detecting means includes a light emitting element and a light receiving element disposed in an opposing relationship to each other.

21. An agitating type washing machine according to claim 19, in which said last-mentioned detecting means includes a magnetic resistor element and an magnet disposed in an opposing relationship to each other.

22. An agitating type washing machine according to claim 19, in which said last-mentioned means includes a Hall element and a magnet disposed in an opposing relationship to each other.

23. An agitating type washing machine according to claim 19, in which said detection disk has an outer circumferen-tial end bent substantially perpendicularly thereto to form a side wall in which a plurality of recesses of a predetermined width are formed in an equally spaced relation-ship from each other.

24. An agitating type washing machine according to claim 1, in which said rotational angle detecting means includes a magnet which rotates in response to rotation of said agitating wheel, and a detector disposed adjacent said magnet.

25. An agitating type washing machine according to claim 24, in which said magnet is integrally formed on a rotary shaft of said motor.

26. An agitating type washing machine according to claim 24, in which said detector is a generating coil.

27. An agitating type washing machine according to claim 24, in which said detector is a magnetic resistor element.