US3088303A - Automatic washing machine having a variable speed drive - Google Patents

Automatic washing machine having a variable speed drive Download PDF

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Publication number
US3088303A
US3088303A US139584A US13958461A US3088303A US 3088303 A US3088303 A US 3088303A US 139584 A US139584 A US 139584A US 13958461 A US13958461 A US 13958461A US 3088303 A US3088303 A US 3088303A
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United States
Prior art keywords
speed
drum
transmission
sheave
belt
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Expired - Lifetime
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US139584A
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English (en)
Inventor
Schmettow Erich
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SEG Hausgeraete GmbH
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Siemens Elektrogaerate GmbH
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    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06F—LAUNDERING, DRYING, IRONING, PRESSING OR FOLDING TEXTILE ARTICLES
    • D06F37/00—Details specific to washing machines covered by groups D06F21/00 - D06F25/00
    • D06F37/30—Driving arrangements 
    • D06F37/36—Driving arrangements  for rotating the receptacle at more than one speed

Definitions

  • My invention relates to drum-type washing machines, particularly to automatic electric washers, in which a laundry-receiving drum is driven from an electric motor for slow rotation of the drum during washing and rinsing and fast rotation during subsequent spin-drying.
  • Such difierent rotating speeds of the drum can be obtained and exclusively controlled with the aid of -multi stage mechanical speed-change transmissions, but such transmissions occupy much space and represent an expensive component it three or more transmission rat1os are required.
  • the expenditure in material and space increases considerably with the ratio of the required maximum (spinning) and minimum (washing) speeds.
  • the spinning speed must be kept as high as feasible, Whereas the washing speed for best laundering must have a much lower value, usually at about 50 rpm.
  • the electric motors preferably employed for washing machines are of the squirrel-cage type, because they are not susceptible to trouble by sparking and require virtually no maintenance, and since such motors have a poor starting characteristic, namely a low torque at low speed and hence very low starting power, the design of a drive for drum-type washers employing such motors involves considerable difficulties which, as a rule, can be overcome only with heavy, large and expensive motors and/or with the aid of large and complicated transmission mechanisms.
  • Another possibility of adjusting different driving speeds resides in the use of a pole-switchable squirrelcage motor.
  • the necessary motors would have to have a very high pole-number ratio, for example 2:24 or more. Such motors are excessively heavy and expensive.
  • Another object of my invention is to devise a drive for such washing machines which, in the event the operating voltage should fail during the spinning operation, will automatically and without appreciable auxiliary devices, return into an operating condition in which the drive can readily commence with a new operating process. That is, the washing machine when operating in dryspinning operation and then encountering voltage failure is supposed to return with particularly simple means and in a reliable manner into an operating condition which, as to drum speed, either corresponds to the wash ing stage or approaches it sufficiently to permit restarting the motor with a sufdcient starting torque until the speed is automatically increased again up to the spinning value.
  • I provide the drum-type washing machine between the electric drive motor and the laundry-receiving drum with a variable-speed transmis- 3,988,393 Patented May 7, 1963 sion mechanism whose transmission ratio is continuously controllable from a lower to an upper limit value, in combination with a speed-responsive regulating means which preferably under direct or indirect control by the programming or other control device of the washing machine, automatically increase the drum speed up to the desired high spinning speed.
  • the transmission mech anism thus automatically controlled then operate constrainedly to always maintain the drive motor at a favorable point of its torque characteristic while the speed of the drum is being built up to the spin-drying value.
  • washing-machine drive can readily be so designed that it will automatically return to washing speed in the event the drive motor is subjected to voltage failure.
  • the above-mentioned control and resetting operations are obtained by providing the ratio-regulating means of the transmission with a centrifugal device, such as a weight movable in dependence upon centrifugal force, for continuously varying the drum-speed.
  • a centrifugally regulated transmission is automatically effective to increase the drum speed up to the desired maximum value at the beginning of a spin-drying operation and also sets the transmission mechanism back to low speed in the event of voltage failure.
  • the electric drive motor of the washing machine always operates at a fixed speed and the speed change of the drum is effected exclusively by the change in transmission ratio within the transmission mechanism connecting the motor with the drum.
  • a considerable further improvement is achieved by providing for the input member of the regulatable transmission mechanism two selective speed steps, a lower speed to be effective during washing operation and a higher speed to be effective for spin-drying operation, the transmission mechanism having a fixed transmission ratio at the lower speed of its input member and commencing its ratio-changing operation only when the speed of the input member is switched to the higher value.
  • This combination of the variable-ratio transmission with a twostep primary drive affords covering a particularly great range of speeds with relatively simple means.
  • the change between the two steps of input speed for the variable-ratio transmission is effected by means of a two-stage speed-change gearing between a single-speed electric motor and the input member of the transmission mechanism.
  • a control pulse supplied from the programming or control device of the washing machine namely so that when this device switches the machine from washing to spinning, the gear transmission is simultaneously switched from low gear to high gear
  • the regulator of the continuously variable transmission mechanism being so set that it responds to the switching to increased primary driving speed, thus commencing the above-described automatic increase of the drum speed up to the desired spinning speed.
  • the change in input speed applied to the input member of the variable-ratio transmission mechanism is effected by providing the machine with a pole-switchable induction motor which in this case may have a relatively simple design because its pole number ratio need only be moderate, for example 2:4, as the further increase in drum speed is effected by the variable transmission between motor and drum.
  • variable-ratio transmission comprises an endless V-belt with belt sheaves of adjustable effective diameter, belt transmission of this type being generally known as such.
  • the diameter-changing control of one or both belt sheaves can then be effected directly by the centrifugal regulator cooperating with a counter spring.
  • mount the spring it is preferable to mount the spring, to oppose the centrifugal force, upon the displaceable portion of one of the sheaves and to mount the centrifugal weights upon the displaceable portion of the other sheave.
  • the spring and the pro-tension produced thereby have the effect of determining the rotating speed at which the centrifugal regulator will commence operating, and the same spring then simultaneously serves to maintain substantially uniform tension in the belt.
  • a compensating spring is mounted on the intermediate shaft between an axially fixed belt portion and the axially movable belt portions, and the force of the compensating spring is directed against the action of the counter spring mounted on the drum shaft, thus reducing the axial stress imposed upon the belt in the fast running transmission stage.
  • FIG. 1 shows schematically the components of a drumtype washing machine essential to the invention including the laundry-receiving drum, the variable-ratio trans- 5- mission, a pole-switchable, drive motor and a programcontrol device.
  • FIG. 2 shows schematically in a substantially similar manner a washing machine with a single-speed motor and a two-stage speed-change gear interposed between the motor and the variable-ratio transmission.
  • FIG. 3 shows schematically a side view of part of FIG. 1 or 2.
  • FIG. 4 shows a side view similar to FIG. 3 but relating to a somewhat modified design.
  • FIGS. 5a and 5b illustrate in section the upper and lower belt sheaves respectively of the variable-ratio transmission according to FIGS. 1 to 4, each illustration showing two different operating positions.
  • FIG. 6 is a speed-time diagram explanatory of the performance of machines according to the invention.
  • FIG. 7 shows in section a two-stage belt transmission of variable ratio applicable in washing machines otherwise corresponding to those of the preceding embodiments.
  • FIG. 8 is an explanatory diagramrelating to the performance of the transmission according to FIG. 7.
  • the drum 1 of a washing machine is driven from a pole-switchable squirrel-cage motor capable of selectively operating at two speeds depending upon which group of poles is energized at a time.
  • motors are commercially available as standard products. They may have two and four poles, for example, to operate at a speed ratio of 2: 1.
  • Driving power is transmitted from the shaft 11 of the motor 2 to the shaft 19 of the drum by a variable-ratio mechanism consisting of a V-belt drive which comprises a two-part belt sheave 3 on the drum shaft 19, a two-part belt sheave 4 on the motor shaft 1 1, and an endless V-belt 8.
  • the motor 2 is energized from power-supply terminals 20 under control by a programming control device 7 illustrated as a drum-type contactor in planar developed form, which is provided with contact segments 5 and fixed contacts 6.
  • the control device 7 is essentially an electrically driven timer as customary for automatic washing machines.
  • the control device 7 When the control device 7 is in Low position, one group of poles in motor 2 is active for operation of low speed and the drum 1 is driven for washing operation.
  • the device 7 advances to High posi-' tion the other group of poles in motor 2 is energized for driving the drum 1 at higher speed.
  • the transmission 3, 4, 8 now becomes effective to change its transmission ratio so as to gradually increase the drum speed above the value that it would assume if the drum were simply driven at the speed of motor 2. Such increase continues until the drum 1 has reached the desired high spin-drying speed. Details of the variable-ratio transmission and its operation will be described in a later place.
  • FIG. 2 The embodiment schematically illustrated in FIG. 2 is to some extent similar to that of FIG. 1, identical components being denoted by the same reference numerals respectively.
  • a single-speed two-pole drive motor 22 is used. It drives a two-staged mechanical gear transmission 24 which in turn drives the input sheave 4 of the above-mentioned variableratio transmission.
  • the two speed steps of gear transmission 24 are electromagnetically controlled by respective control windings 26 and 28 so that only the one gear step is active whose appertaining control winding is energized at a time.
  • the program control device 27, when turning from Stop to Low position, energizes'by means of its contact segments 25, the motor 22 and simultaneously the control winding 26 so that the drum 1 is driven for washing operation at slow speed.
  • control device 27 switches .to High position, the motor 22 remains energized but now the control winding 28 is energized so that the input sheave 4 of the variable-ratio transmission operates at higher speed and the variable-ratio transmission commences to increase the drum speed up to the spinning value.
  • each belt sheave 3 and 4 in FIGS. 1 and 2 comprises a half-portion fixed to the shaft on which the sheave is mounted, whereas the other half portion is axially displaceable so that the V-groove of the sheave can become wider or narrower.
  • FIG. 4 illustrates a modified embodiment in which the belt sheave 3 on the shaft 19 or drum 1 has a fixed effective diameter (i.e. does not consist of two portions of which one is axially displaceable relative to the other) and only the belt sheave 4 on the motor shaft 11 can vary its effective diameter for changing the transmission ratio.
  • a tensioning roller 9 is provided for compensating the different belt lengths during changes in transmission ratio.
  • the roller 9 is pressed against the belt 3 in the direction of the arrow, for example by means of a spring, and may be journalled, for example, on an arm (not shown) pivotally mounted on the motor shaft 11.
  • the tensioning roller 9 is in the full-line position at the left, and the V-belt 8 ms with the smallest diameter of the driving sheave 4 on the motor shaft 11. At the highest drum speed, the roller 9 occupies the broken-line position, and the driving sheave 4 is active with its largest diameter.
  • the driving belt sheave 4 in a machine according to FIGS. 1 or 2 comprises a disc 12 rigidly joined with the shaft 11 of the electric motor 2, and a disc 13 axially displaceable on the shaft 11.
  • a helical pressure spring 14 tends to force the disc 13 away from disc 12 to the limit position shown in the upper portion of FIG. 5b.
  • the driving belt is in its innermost operating position 8a so that a relatively small driving-sheave diameter is effective.
  • This position corresponds to the washing operation of the drum.
  • the spin-drying operation initiated by switching of the motor 2 (FIG. 1) to high speed, the revolving speed of the motor shaft 11 increases.
  • the disc 13 is gradually forced toward the disc 12 in opposition to the force of spring 14 to the limit position shown in the lower portion of FIG. 5b.
  • the driving belt is in the position 8b in which the largest diameter of the driving sheave is effective.
  • the driven sheave 3 (FIG. 5a) comprises a disc 20 rigidly joined with the shaft 19 of the washer drum 1, and a disc 21 am'ally displaceable relative to disc 20.
  • a helical compression spring 22 forces the disc 21 toward the disc 20, so that the disc 21 assumes the brokenline position during washing operation and the driving belt occupies the position 8a corresponding to the largest effective diameter of the driven sheave 3.
  • the belt is forced downward to the position 8b so that the disc 21 occupies the fullline position in which a smaller diameter of the driven sheave 3 is effective. This is due to the action of the centrifugal Weight 15.
  • the upper sheave 3 may also be provided with a centrifugal device corresponding to that shown in FIG. Sb and set to operate simultaneously with, and in the same manner as, the device described above with reference to FIG. 5b.
  • the regulator 15 causes the speed of drum 1 to be increased by the continuously regulatable transmis sion up to the maximum value which is reached at the moment t That is, from moment 1 to moment t the drum speed is being increased from the low washing speed up to the spinning speed, and the spin-drying operation proper commences with the moment I
  • a two-stage variable-ratio transmission embodying the above-mentioned features of the invention will be described presently with reference to FIG. 7 and with reference to the diagram of FIG. 8 indicating the forces acting upon the counter spring and compensating spring in dependence upon the amount displacement.
  • the transmission mechanism "shown in FIG. 7 is applicable in lieu of the single-stage variable-ratio transmission of the embodiments described above, in conjunction with an electric drive motor and a control device as shown in FIG. 1, or in conjunction with a motor, twostep gear transmission and control device as shown in FIG. 2. It may be assumed, for example, that the input sheave of the variable-ratio mechanism according to FIG. 7 is driven from a pole-switchable motor with two and four selectively operable poles. Denoted by 31 in FIG. 7 is the shaft of the washer drum, by 32 the shaft of the motor, and by 33 the above-mentioned intermediate shaft.
  • the drum shaft 31 carries an axially fixed sheave disc 46 and an axially displaceable disc 47, both cooperating with the V-belt 45.
  • a helical counter spring 48 mounted on the drum shaft 31 tends to force the displaceable disc 47 toward the fixed disc 46.
  • a helical compensating spring 49 is mounted on the intermediate shaft 33 between the axially fixed portion 42 and the axially displaceable middle structure 43, 44. Spring 49 acts in opposition to the force of the counter spring 48.
  • the horizontal reference line indicates the direction of displacement caused by the centrifugal motion of the Weights 38, this motion being in the direction of the arrow 40 and causing a compression of the counter spring 48 and of the compensating spring 49.
  • the amount of displacement thus centrifugally effected extends from a to Plotted on the displacement line are the spring forces of the counter spring 48 (G G and the spring forces of the compensating spring 49 (A A so that the force difference F or F to be overcome 'by the centrifugal force of the weights 38 is apparent.
  • the increase of the difference valve from F to F can be dimensioned by corresponding choice of the springs 48 and 49 so that it corresponds to the increase in centrifugal force acting upon the weight 38 during automatic regulating operation.
  • the increase in force of the counter spring on the drum axis can be kept very small, in some cases even negative, corresponding to the torques to be transmitted on the drum shaft.
  • the increase in the difierence between the two spring forces can be so dimensioned that it corresponds to the increase of the centrifugal force acting upon the centrifugal regulator so that a favorable regulating characteristic is obtained.
  • a drum-type washing machine having a laundryreceiving rotatable drum, drive means for said drum, and a program control device connected with said drive means for sequentially switching it to operate at a lower speed range for Washing operation and at higher speed range for centrifuging operation
  • said V-belt transmission having a variable transmission ratio, said first sheave being of variable effective diameter and coaxial-1y joined with said drive means; a counter spring engaging said first sheave and biasing it in the direction required to reduce said transmission ratio, said centrifugal weight device being movable outwardly by centrifugal force and operatively connected with said first sheave for varying said diameter in opposition to said spring to increase said transmission ratio.
  • a washing machine including a counter spring in engagement with said displaceable disc of said first one of said sheaves for biasing it away from said fixed disc of said one sheave, and said weight means having a pivot axis in fixed relation to said axially fixed disc of said one sheave and being centrifugally movable outwardly about said axis for displacing said displaceable disc of said one sheave in opposition to force transmitted by said belt from said spring.
  • said counter spring and said compensating spring having respective spring characteristics adapted to each other so that the difference of their respective forces increases substantially in accordance with the increase in centrifugal force of said centrifugal device during the ratio-changing operation of the transmission mechanism.

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  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Control Of Washing Machine And Dryer (AREA)
US139584A 1960-09-23 1961-09-19 Automatic washing machine having a variable speed drive Expired - Lifetime US3088303A (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DES0070492 1960-09-23
DES0073564 1961-04-20
DES0074066 1961-05-19

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CH (1) CH400075A (fr)
FR (1) FR1301619A (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3381503A (en) * 1967-08-07 1968-05-07 Robertshaw Controls Co Washing machine system or the like
US4206659A (en) * 1977-04-15 1980-06-10 Volvo Car B.V. Variable V-belt drive for a vehicle

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2253634A (en) * 1939-03-31 1941-08-26 Briggs & Stratton Corp Pulley
US2311924A (en) * 1937-04-19 1943-02-23 Bendix Home Appliances Inc Cleaning machine
US2496061A (en) * 1946-07-19 1950-01-31 Charles H Miner Variable-speed clutch pulley
US2651210A (en) * 1951-05-26 1953-09-08 Int Harvester Co Centrifugally controlled variable speed v-belt power transmission
US2881633A (en) * 1956-07-19 1959-04-14 Gen Electric Combination washer-dryer drive mechanism
US2942447A (en) * 1957-08-07 1960-06-28 Whirlpool Co Clothes washing and extracting machine

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2311924A (en) * 1937-04-19 1943-02-23 Bendix Home Appliances Inc Cleaning machine
US2253634A (en) * 1939-03-31 1941-08-26 Briggs & Stratton Corp Pulley
US2496061A (en) * 1946-07-19 1950-01-31 Charles H Miner Variable-speed clutch pulley
US2651210A (en) * 1951-05-26 1953-09-08 Int Harvester Co Centrifugally controlled variable speed v-belt power transmission
US2881633A (en) * 1956-07-19 1959-04-14 Gen Electric Combination washer-dryer drive mechanism
US2942447A (en) * 1957-08-07 1960-06-28 Whirlpool Co Clothes washing and extracting machine

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3381503A (en) * 1967-08-07 1968-05-07 Robertshaw Controls Co Washing machine system or the like
US4206659A (en) * 1977-04-15 1980-06-10 Volvo Car B.V. Variable V-belt drive for a vehicle

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CH400075A (de) 1965-10-15
FR1301619A (fr) 1962-08-17

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