US3750429A

US3750429A - Control for an automatic washer

Info

Publication number: US3750429A
Application number: US00128369A
Authority: US
Inventors: H Gorsuch
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1971-03-26
Filing date: 1971-03-26
Publication date: 1973-08-07
Anticipated expiration: 1990-08-07

Abstract

This invention provides a control for an automatic washer having a self-contained heating element for heating the wash water to the desired temperature. In the preferred embodiment the control is shown in conjunction with 380v/220v, three-phase, four wire circuit providing a high voltage for the heater and a lower voltage for the controls and drive means of the machine. The control includes a switch directly connected to a heat sensing element intimately disposed on the heater. The switch has a plurality of forward contacts connected to the heater and back contacts connected to a timer motor so that when the heat sensing element indicates heat should be added to the wash water, the forward contacts are closed and the back contacts opened so that the timer does not advance during the period the heater is energized. Further, the controls include two switches centrifugally operated which close when the motor is up to running speed. The switches are connected to the heater so the drive motor must be running before the heater can be energized. The heat sensing element in contact with the heater is grounded so that any electrical leakage from the heater flows through the sensing element causing it to become warm and move the switch to its heater open position thereby deenergizing the heater.

Description

United States Patent [191' Gorsuch 1 Aug. 7, 1973 CONTROL FOR AN AUTOMATIC WASHER [75] Inventor: Harold F. Gorsuch, Mansfield, Ohio [73] Assignee: Westinghouse Electric Corporation,

Pittsburgh, Pa.

[22] Filed: Mar. 26, 1971 [21] Appl. No.: 128,369

[52] [1.8. Ci. 68/12 R, 68/16 [51] Int. Cl D061. 33/02, D06f 39/04 [58] Field of Search 68/12 R, 15, 16

[56] References Cited UNITED STATES PATENTS 2,892,334 6/l959 Gray 68/12 R 3,388,566 6/1968 Kaper et al. 68/12 R 3,005,328 10/1961 Gehrig 68/16 R X 2,914,935 l2/l959 Sampsel 68/12 R Primary Examiner-William I. Price Assistant Examiner-Philip R. Coe Attorney-F. H. Henson, F. C. Arenz and F. A. Winans [57] ABSTRACT This invention provides a control for an automatic washer having a self-contained heating element for heating the wash water to the desired temperature. in

the preferred embodiment the control is shown in conjunction with 380v/220v, three-phase, four wire circuit providing a high voltage for the heater and a lower voltage t'or the controls and drive means of the machine. The control includes a switch directly connected to a heat sensing element intimately disposed on the heater. The switch has a plurality of forward contacts connected to the heater and back contacts connected to a timer motor so that when the heat sensing element indicates heat should be added to the wash water, the forward contacts are closed and the back contacts opened so that the timer does not advance during the period the heater is energizedl Further, the controls include two switches centrifugally operated which close when the motor is up to running speed. The switches are connected to the heater so the drive motor must be running before the heater can be energized. The heat sensing element in contact with the heater is grounded so that any electrical leakage from the heater flows through the sensing element causing it to become warm and move the switch to its heater open position thereby deenergizing the heater.

3 Claims, 3 Drawing Figures PATENIEU M16 7 I973 SHEET 1 0F 2 FIG. I

BACKGROUND OF THE INVENTION 1. Field of the Invention DESCRIPTION OF THE PREFERRED EMBODIMENT 1 The present invention of a control for an automatic This invention relates generally to an automatic washing machine has greatest utility in controlling a washer and more particularly to control means for such a washer having means for heating the water to the desired washing temperature after it has entered the washing machine.

2. Description of the Prior Art Washers of the type wherein the water is heated after it enters the machine are well known in the art and generally are extensively used in countries other than the United States.

Further. it is well known to have such washing machines operated through controls capable of a multiphase hook-up such as is common in Scandinavian countries, and described as: three-phase, four-wire, 380v/220v; three-phase, three-wire, 220v; and onephase, two-wire, 220v.

The control circuits are usually such that the threephase high voltage is used in the heaters, with a few countries even requiring the high voltage for heaters to shorten the overall wash time, and low voltage used in the control circuit and drive motor of the machine. This type of system is generally expensive and complex and being such, creates many service problems.

The present invention eliminates theabove deficiencies mainly by eliminating a rather expensive contactor switch and a thermal responsive switch, and provides a control circuit wherein the heaters can be connected for delta, wye, threeor single phase service with the connection to the phase lines of the heater controlled through the program timer, a hydraulic or hot gas remote thermostat, a door switch and centrifugally operated contacts responsive to the speed of the main m0- tor.

SUMMARY OF THE INVENTION The preferred invention provides a three-phase four wire 380v/220v hook-up for energizing heaters at a generally high voltage and operating the controls and the drive motor of the machine at a lower voltage. The controls utilize a hydraulic remote bulb thermostat intimately attachedto the heaters to control a switch which either closes a circuit to the timer motor or to the heater elements. This permits energization of the heaters without advancing the timer during the wash portion of the program cycle. The heater circuit further includes speed responsive switches associated with the drive motor so that the heater will not be energized unless the main drive motor is operating. The hydraulic thermostat is grounded so that any electrical leakage in the heater passes therethrough causing it to heat and open the switch to the elements.

DESCRIPTION OF THE DRAWINGS FIG. I is an isometric partial view of the heater element disposed in the outer tub of the washer and schematically showing the hydraulic remote bulb thermostat;

FIG. 2 is a schematic circuit of the previously used control; and

FIG. 3 is a schematic circuit of the control of the present invention.

washing machine having the capability of heating the water to the-desired washing temperature. As such, the controls are shown as used in a generally well known automatic washer of the type generally described in (LS. Pat. No. 2,914,935 relating to a front loading ty'pe automatic washer and having the same assignee as the present invention. That patent shows the heater in the recirculation line; however, the present practice is to place the heater structure in the sump portion of the outer tub for directly heating the water therein. Thus, referring to FIG. I, a section of the outer tub 10 of a well known front loading washer is shown having a sump portion -l2 formed in the bottom thereof. A heater structure 14 generally having three separate sheathed electrical resistance heater elements is positioned in the sump portion by a support plate 16 fastened, as by bolting, to a flange of the outer tub 10. The

terminals

14a, 14b and of the heater structure extend through the support plate for connection to the control as will be described. A well known manually adjustable hydraulic thermostat 18 having a remote bulb portion 20 attached in intimate contact to the heater as shown in FIG. 1, and a capillary tube 22 is provided to drive a three pole, single-throw switch 24 of the present invention which is remotely mounted on the washer. v

The prior control system for such a machine utilized two such hydraulic thermostats, one of which was manually adjustable and one of which was preset, plus a generally expensive relay controlled switch or contactor to control the energization of the heater structure. To better understand the prior control circuit reference is now made to the schematic diagram of the previous control as shown in FIG. 2. The control including the electrical components of the machine energized thereby, generally comprised a timer 26 which included a plurality of

contacts

28, 29, 30, 31, 32, 33 controlled by a preset program such as a plurality of cams (not shown) driven bya timer motor 34. The contacts opened and closed as the motor advanced the cams to provide various modes of operation of the machine.

Electricity from a household outlet supplying, -in this case, 380v/220v, three-phase current energized the circuit through a line switch 36 which was manually closed. The circuit can probably best be understood by explaining the sequence of the various modes which form a complete wash cycle.

On initiation of the cycle, line switch 36 was manually closed and timer 26 manually advanced to close contact 28 which energized a water solenoid 38 through a water level control switch 40 to permit water to enter the machine. Contacts 30 were closed simultaneously with contact 28 so that the main drive motor 42 was energized (assuming the door is closed so that door switch 44 is closed) through a line lead connecting the line to a terminal block 48. Another line lead 50 was also connected to the terminal block 48. The terminal block in turn was connected to a contactor 52 (shown connected by three wires in a wye configuration providing 380v between each wire). The contactor 52 included three normally

open heater switches

54, 55, 56 and a normally closed back switch 58 completing the circuit to the motor 42. Thus, the clothes tumbled at the same time the machine was being filled.

After the water reached the desired level the water level control switch 40 moved to a back contact 40a and completed the circuit to the timer motor 34 (the other side of which was connected to back switch 58) which advanced the cams to open contact 28 and shut the incoming water off and closed contact 29 which had a lead 62 to water temperature thermostat 64 and contactor coil 66, which in turn were connected to line lead 46.

It should be noted that thermostat 64 comprised a manually adjustable hydraulic thermostat having aremote bulb disposed in the sump portion 12 to sense the water temperature and opened the heater circuit only when the water reached the desired temperature range.

Thus, with the thermostat 64 closed by the cold water introduced into the machine, the contactor coil 66 became energized which caused

heater switches

54, 55 and 56 of the contactor to close and back switch 58 to open. Closing-of

switches

54, 55 and 56 energized the heater structure 14 while opening back switch 58 deenergized the main drive motor 42 and the timer motor 34. Thus during the heating portion of the cycle the clothes were not tumbled and the program did not advance.

Once the water was heated-to the desired temperature and the contactor coil 66 deenergized, the clothes were tumbled by the main drive motor 42 in the washing mode of the cycle, with intermittent off periods whenever the water temperature fell below the preset range and the heater structure 14 was energized.

Just before termination of the washing mode, the timer motor 34 advanced the cams to close contacts 33 to energize the time motor directly from the line switch 36 (being energized through the water level control switch until this point insured that the timer would not advance unless there was sufficient water to wash the clothes). Further advancement of the cams then opened contacts 29 which removed the water temperature thermostat 64 and the contactor coil 66 from the circuit. This marked termination of the wash mode and removed heater switches 54, and 56 of the contactor 52 from the circuit throughout the remainder of the cycle. Subsequent sequential closing of

timer contacts

31 and 32, effected by further cam advancement, respectively energized the pump solenoid 68 and spin solenoid 70. A further rinse mode was provided by once againclosing timer contacts 28 which energized the water solenoid 38. However, normally the rinse water was not heated so the heater structure 14 remained deenergized by maintaining contacts 29 open. After the rinse the pump and spin

solenoids

68 and 70 were again energized to extract the water from the machine and complete the wash cycle.

Still referring to FIG. 2 it will be noted that the

heater lines

14a, 14b and [4c leading from the contactor 52 to the heater structure 14 contain a switch 72 in series with two of them. Switch 72 has typically been a second hydraulic thermostat preset to open at a high temperature and placed in intimate contact with the heater 14 to deenergize the heater should the tub fail to fill with water, yet through some malfunction, the contactor switches 54, 55 and 56 become closed. This provided a safety feature for the high voltage heaters.

Another feature of the prior control of FIG. 2 resided cuit of the present invention is shown and will be dc-' scribed using reference numerals identified in FIG. 2 for the same or equivalent structure but further identi' fied by a prime notation.

As before, the cycle is initiated by manually closing the line switch 36' and manually advancing the time 26' to close contacts 28' assuming door switch 44' is" also closed, to fill the machine to the desired level. It should be noted at this point that, contrary to the previously described control, timer contacts 30 to the main motor 42 are not closed upon initiation of the cycle and thus the clothes lie dormant in the machine while it is being filled. However, upon completion of the filling, water level control switch 40 moves to a back contact 40a having a lead to the main drive motor 42' to start the tumbling.

Again the main drive motor 42 is a capacitor start type motor; however, the centrifugal switch 43' for deenergizing the start winding 42a is a double-throw, single-pole switch having a back contact 72 such that when the motor has attained running speed the centrifugal switch 43' opens the circuit to the start winding- 42a' and closes on contact 72 which completes the cir cuit to cam controlled contacts 74 in the timer.

Timer contacts

74 and 86 are also closed upon initiation of the cycle. Contacts 74 have one lead 76 connected to two

contacts

78 and 80 of a manually adjustable hydraulic thermostat controlled switch 24 with contacts 78 being normally closed to another timer controlled contact 330' and contact 80 being normally opened to one line 14b of the heater .14.

Timer contacts 86 have one lead 88 to a third contact 82 of switch 24 which is also normally open to another line 14a of the heater l4, and another lead 90 to another centrifugally controlled switch 92 mounted on the motor which is also closed upon the motor 42' at-' justed by the user. By placing the bulb 20 in contact with the heater, it also sets as a high temperature safety control thermostat.

Contacts 7! of switch 24 are connected to upper contacts 33a of cam controlled contacts 33 leading to the timer motor 34'. Contacts 33 are also closed upon initiation of the wash cycle.

Thus, it is seen that through the above-described circuitry, after the main drive motor has initially attained running speed, centrifugslly operated

contacts

72 and 92 are closed. Further, the hydraulic thermostat 18 having sensed the cool initial water, moves switch 24 so that contacts and 82 are closed and thus the heater 14' is energized.

As contacts 78 of switch 24 are opened when the

contacts

80 and 82 are closed, there is no complete circuit to the timer motor 34' during energization of the heater 14"but only after the thermostat 18 has been satisfied does it open

contacts

80 and 82, deenergizing the heater and closing contacts 78 to energizethe timer motor 34'.

Thus, contrary to the previously described control circuit, the main drive motor 42 continues to run even during the periods the heater 14' is energized; however, as before, the timer does not advance during heater on" time. Further, it is seen that the heater 14' will not be energized unless the main motor 42' is running as the heater requires the centrifugally controlled

switches

72 and 92 to be closed.

The heater 14' is intermittently energized during the washing mode as controlled through the

contacts

80 and 82 of the thermostatically controlled switch 24. Just prior to the termination of the washing mode, timer motor 34 advances the timer cams to close timer contacts 30' and 33 thus energizing both'the main motor 42' and the timer motor 34' from the line switch 36'. Further advancement of the timer opens

timer contacts

74 and 86 to permanently deenergize the heater 14' for the remainder of the cycle.

The cycle is completed by further sequential closing of

contacts

31 and 32 to energize the pump solenoid 68' and spin solenoid 70 respectively. A further rinse cycle can again he provided as previously discussed.

The controls of the present invention have been shown connected such that the timer 26' and motors 34' and 42' are operated on 220v by being connected between one phase and the center tap of a wye connection at the terminal block 48' with the heater 14, connected across three phases to accommodate 380 volts; however, it is apparent that this control is also adaptable to three-phase delta connection or to a singlephase source. V

An important safety feature of the presentinvention is provided by grounding the capillary tube of the hydraulic thermostat 18. As shown in FIG. 1 this is done by connecting a wire 96 directly from it to the cabinet of the machine which is grounded upon installation. Thus, with the bulb portion being in intimate contact with the high voltage heater 14', any current leakage will flow directly through the bulb and capillary tube to the ground. This will cause the hydraulic thermostat to heat (acting itself as a resistor) to the point where it causes switch 24 to open and deenergize the heater 14'.

it is seen that the control of the present invention eliminates a rather expensive relay type contactor to control the heaters and a hydrulic thermostat present in the prior art control and adds a pair of contacts to the centrifugally operated switch of the motor. The control also provides safer operation and more desirable washing mode in the following manner.

On initiation of the wash cycle the clothes are not tumbled until the tub has been filled, thereby reducing wear on the clothes and eliminating tangling effects that occur when dry or damp clothes are tumbled.

The tub continues to tumble during portions of the washmode when the heater is energized but the timer motor is deenergized thus, in effect, lengthening the wash mode by that amount of time (safely assuming some cleaning takes place even if the water is not at the desired elevated temperature).

perature safety thermostat, and by grounding the thermostat as a' safeguard against current leakage through the heater.

I claim: 1. A control for an automatic washing machine having a main drive motor and heater structure including three separate heater elements each energized from separate phase lines of a three phase electricsource for heating the water in the machine, said control including a plurality of movable contacts and means for selectively closing said contacts according to a predetermined program, and means for advancing said contact closing means through a complete cycle of operation, said control further comprising:

first circuit means forenergizing said main motor for a washing operation, said first circuit means including a water level control switch having a-position for maintaining said first circuit means in an open condition until water entering said machine reaches a predetermined level, and a first normally open door switch manually movable to a closed position whereby said main motor is not energized until said first normally open door switch is closedand said water reaches the predetermined level; second circuit means for energizing said heater structure, said second circuit means including a second normally open door switch manually movable to a closed position, a normally open speed responsive switch means operative to a closed position in response to a predetermined speed of said main motor, and a temperature responsive switch means operative to an open position in response to a predetermined adequate water temperatureand a closed positionin response to a predetermined minimum water temperature whereby energization of said heater structure requires said normally open door switch being closed, operation of said motor at a predetermined speed and said water temperature being at or below said predetermined minimum temperature; and,

third circuit means for energization of said contact advancing means, said third circuit means comprising a second temperature responsive switch means operative to an open position in response to a minimum water temperature and to a closed position in response to an adequate water temperature, and said first normally open door switch whereby energization of said advancing means during said washing operation requires both said first normally open door switch being manually closed and said water temperature being adequate.

2. The control of claim 1 further including a remote bulb hydraulic thermostat having a portion thereof in intimate contact withsaid heater structure and wherein both said temperature responsive switch means of said second circuit means and said temperature responsive switch means of said thirdeircuit means are operably connected to said thermostat whereby said thermostat either deenergizes the heaters and energizes the adture and operating said temperature responsive switch means of said second circuit meansfor energizing said heater structure to an open position thereby deenergizing said heaters.

Claims

1. A control for an automatic washing machine having a main drive motor and heater structure including three separate heater elements each energized from separate phase lines of a three phase electric source for heating the water in the machine, said control including a plurality of movable contacts and means for selectively closing said contacts according to a predetermined program, and means for advancing said contact closing means through a complete cycle of operation, said control further comprising: first circuit means for energizing said main motor for a washing operation, said first circuit means including a water level control switch having a positioN for maintaining said first circuit means in an open condition until water entering said machine reaches a predetermined level, and a first normally open door switch manually movable to a closed position whereby said main motor is not energized until said first normally open door switch is closed and said water reaches the predetermined level; second circuit means for energizing said heater structure, said second circuit means including a second normally open door switch manually movable to a closed position, a normally open speed responsive switch means operative to a closed position in response to a predetermined speed of said main motor, and a temperature responsive switch means operative to an open position in response to a predetermined adequate water temperature and a closed position in response to a predetermined minimum water temperature whereby energization of said heater structure requires said normally open door switch being closed, operation of said motor at a predetermined speed and said water temperature being at or below said predetermined minimum temperature; and, third circuit means for energization of said contact advancing means, said third circuit means comprising a second temperature responsive switch means operative to an open position in response to a minimum water temperature and to a closed position in response to an adequate water temperature, and said first normally open door switch whereby energization of said advancing means during said washing operation requires both said first normally open door switch being manually closed and said water temperature being adequate.

2. The control of claim 1 further including a remote bulb hydraulic thermostat having a portion thereof in intimate contact with said heater structure and wherein both said temperature responsive switch means of said second circuit means and said temperature responsive switch means of said third circuit means are operably connected to said thermostat whereby said thermostat either deenergizes the heaters and energizes the advancing means or energizes the heaters and deenergizes the advancing means respectively.

3. The control of claim 2 including means to ground said thermostat whereby current leakage from said heater will flow therethrough causing said thermostat to heat beyond said predetermined adequate temperature and operating said temperature responsive switch means of said second circuit means for energizing said heater structure to an open position thereby deenergizing said heaters.